BEST PRACTICE DESIGN GUIDE FOR PUMPING SYSTEMS Version 1.0 October 2011
OCT 2011
BEST PRACTICE DESIGN GUIDE FOR PUMPING SYSTEMS VERSION 1.0 Date: October 2011
Quality Assurance Statement
Office Address
DEN-1
Prepared by
Timur Ayvaz (see list of contributors)
Reviewed by
Tino Senon, George Tey
Approved for issue by
Tino Senon
Revision Schedule Rev No.
Date
Description
Prepared By
Reviewed By
Page | Chapter 1-1
Approved By
Disclaimer This document contains information from MWH which may be confidential or proprietary. Any unauthorized use of the information contained herein is strictly prohibited and MWH shall not be liable for any use outside the intended and approved purpose.
OCT 2011
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Page | Chapter 1-1
OCT 2011
1.
INTRODUCTION The design of pumping systems is an important component of MWH’s core business in the municipal water and wastewater industry. Pumping systems convey a variety of liquids into, and out of, treatment plants as well as conveyance systems. It is the responsibility of the pump system design engineer to fully understand the system hydraulics and operating scenarios required by the project. Although many textbooks, reference guides, standards and other publications describing how to design pumping systems exist, most of these publications focus on either general or very specific pumping applications. In addition, some of these publications reflect the authors’ experiences and opinions, but may not necessarily apply to project design applications. This Best Practices Design Guide ("the Guide") provides the design engineer with the relevant information and MWH Best Practices required selecting and sizing the right pump for the required application. The MWH Best Practice Guide was originally developed to document best practices in early 1990 by Tino Senon, Julian Strassle, and Brian Stone under the direction of Dewey Dickson, JMM’s Engineering Director. The first edition was completed and distributed in the Americas but later withdrawn because of some issues in Chapter 1, Hydraulic Considerations. Soon after that, there were several attempts to finish the Guide but were not successful. The 2011 Edition of this Best Practice Guide should be considered the first release and it is a compilation of experience in the US and overseas in designing small, medium and large size pump stations with an aggregate total connected load in excess of 2,000,000 horsepower. In 2008, MWH became a Hydraulic Institute Standards (HIS) Partner and has provided valuable time to review and provide input to the Standards. The Engineer should use the HIS as a reference. This Guide would never been completed without contribution of the following MWH Staff: Atul Yadav
Michael Arroyo
Chris Michalos
Rich Atoulikian
David Baar
Shane Ramcharansingh
David Sudibyo
Steve Hyland
Ed Pascua
Steven Hinman
George Tey
Sushrut Joshi
Jagannath Hosmani
Tim Ayvaz
Jakub Adidjaja
Constantino Senon
Lou Yaussi
1.1.
Scope The purpose of the Guide is to provide guidance for the design of pumping systems for water and wastewater treatment plants and water conveyance systems. It focuses on eight areas: development of the design criteria, sizing and section of pumps, system and efficiency, construction optimization, ancillary systems, interdisciplinary coordination, specification development, and safety. This Guide also includes the following:
MWH Standard P&ID’s for pumping systems
Pump data sheets
Best practices for pumping system layouts
Reference Attachments Page | Chapter 1-1
OCT 2011
Attachment No. A – Pump Station Design Procedure Flow Chart Attachment No. B – Typical Treatment Plant Process Flow Diagrams (C.1, C.2, C.3 and C.4) Attachment No. C – Design of Trench Type Wet Wells by Sanks Attachment No. D – CFD Modelling of Proposed Pump Station by Constantino Senon Attachment No. E - Design Worksheets Attachment No. F - Example Drawings
o Not included in this version of the Guide are valve selection, electrical schematics and conduit drawings, Input/Output (I/O) lists, and valve and auxiliary equipment lists. This information is currently being developed and will be included in future editions. The Guide is applies only to fluids (liquids) typically encountered in water and wastewater treatment facilities, including potable and non-potable water and dilute water/chemical mixtures (for the pumping of chemical solutions, refer to MWH Best Practice Design Guides for Chemical Feed System).
1.2.
Usage
1.2.1.
How to Use this Guide It is impossible for one guide to cover all aspects of pump station design. The Guide is a starting point for the design of pumping system projects designed by MWH Americas, and combines best industry practices with MWH experience. Refer to Attachment A – Pump Station Design Procedure Flow Chart. In addition to this Guide, the design engineer should consider project-specific requirements, MWH quality control, client input and manufacturer’s recommendations. Furthermore, the design engineer must be cognizant of and carefully review requirements mandated by local codes, the governing regulatory agency having jurisdiction and client preferences. Where compliance with such requirements appears to be in conflict with the Guide, the MWH Chief Mechanical Engineer and the MWH Water or Wastewater National Practice Leader must be consulted to reconcile those differences. Each project has its own unique and specific requirements, which may require customization of the Guide's recommended practices. The design engineer should always verify the client’s operational, performance criteria and review them with the design team throughout the design process. Customization of design may be required in order for the pumping system to meet the required operational performance as well as the client’s expectations. However, the design engineer should not deviate from the Guide without the review and acceptance of the MWH Chief Mechanical Engineer or an approved alternative reviewer. The design engineer should provide the Chief Mechanical Engineer with a list of any deviations on the modification form located in the Appendix G. Although an attempt is made to discuss hydraulic theory, the Guide assumes the design engineer has a fundamental understanding of hydraulics and design. Basic hydraulics, pump characteristics and pump theories are included in the Hydraulic Institute Standards as reference.
1.2.2.
Design Philosophy Regardless of the level at which an engineer becomes involved in the design of a pumping station, whether it be at the conceptual, pre-design or final design phase, it is important to have as complete a picture as possible of the entire system. The Guide attempts to discuss the major topics relevant at all phases of design. Topics include recommendations relative to consultation with the client to determine preferences that may affect the design of equipment. This process involves review of pertinent data, referral to standard designs, manuals and previous designs, discussions with accompany experts and site reconnaissance. Once all data is collected, the engineer should then determine the magnitude and principal features of the pumping station; such as location, capacity, Page | Chapter 1-2
OCT 2011 suction and discharge conditions (including transmission pipeline diameters and lengths), power requirements, and type of pumps (with reasonable alternatives). In addition, all available data regarding the system should be obtained. These data allows the design engineer to determine the magnitude of the total capacity, power requirements, type and number of pumps, type of driving units, and other major features sufficient for preparation of preliminary design. Data collection and calculations involved at all stages of the investigation and design should be summarized and recorded. Final calculations (civil, mechanical, structural, electrical, controls, surge, and cost estimates) should be checked and well documented. A project file should be maintained and records of all computations, memos and letters should be kept in accordance with the project and MWH standards. It is MWH’s policy that pumping systems be as simple and maintenance free as possible, equipment and materials shall be selected to be long-lasting and, in general, to employ designs that have a long record of success. Innovative designs and equipment selection is not discouraged when there are compelling reasons, such as a , project specific requirement, client’s requirements or significant cost savings, but with the knowledge that there may be limited risks involved. In which case, the Engineer must seek the assistance of the Chief Mechanical Engineer or his designated pump station design specialist and exercise due diligence in working with the pump manufacturer to insure that all aspects of design have been addressed to make sure that the pumping system work. Table 1-1 indicates the typical scope of design services relative to the size of the pumps at the station. Table 1-1 Typical Scope of Design Services Relative to Pump Station Size Description
Typical Scope of Design Services
Fractional horsepower pumps (less than 1.0 HP (0.75 kW) such as sump pumps, sample pumps, small lift stations, utility water pumps, etc.
Utilize package system as much as possible. Determine flow, head, horsepower and controls requirement. Select pumps and manufacturer. Establish foot print and show single line piping layout. Normally no detail layout is required other than reference to standard details. Indicate in schematics, if appropriate. Use standard specifications Utilize standard designs if available. Show simple outline layout of equipment and single line piping details. Utilize standard specifications. Proceed on the basis of pre-design then detail design. Utilize Criteria Committee Meeting review (CCM) as discussed in the Delivery Framework. The designs may require additional services such as geo tech, surge analysis, vibration analysis, architectural input and constructability review. Design team should include the Mechanical Chief Engineer or his designated pump station design specialist. All design discipline shall be involved especially electrical and I & C as early as the predesign phase. Alternative layout studies consultation and extensive coordination with equipment manufacturers and substantial (electrical and mechanical) input.
Water and wastewater pumps 2 to 40 hp (1.5 to 30 kW)1 Water and wastewater pumping facilities 50 to 1000 HP (40 to 750 kW)
Water and wastewater pumping facilities with installed total capacity in excess of 1000 HP (750 kW)
1
Low lift pumps (head less than 60 ft (20 m)) require careful review of the system head loss calculation hydraulics. Include velocity head through the pump column in the pump TDH. All pump station hydraulics shall be supported by a system head curve with pump curves superimposed over the system curve.
Page | Chapter 1-3
OCT 2011
1.2.3.
Abbreviations and Definitions Pump nomenclature, abbreviations and definitions as used by the Hydraulic Institute Standards are provided in Appendix F.
1.2.4.
Symbols and Specification References The MWH General Drawing Sheets included pump symbols and can be accessed from the CAD Drafting Standards in the Delivery Framework. The MWH Guide Specifications for pumping equipment is provided in the Delivery Framework arranged by pump type.
1.2.5.
Glossary Appendix E includes commonly used terms through this guide and within the Water and Waste-water Industries.
1.3.
Codes and Standards The codes and standards listed in our Guide Specifications are available through MWH's IHS subscription service as indicated in the Delivery Framework. In addition, the design engineer should become knowledgeable of project-specific and local codes and ordinances within the jurisdiction of the project.
1.4.
References The Guide is based on the references listed below. The design guide attempts to summarize the main discussions in the references; however the design engineer is encouraged to become familiar with these references. In order to determine if there is a copy available in your local office, please contact your supervisor. For further information regarding the delivery process, please see the delivery framework at the following link: http://design-framework/
1.4.1.
Industry
Hydraulic Institute Standards, Parsippany, New Jersey
Internal Flow Systems 2nd Edition, D.S. Miller (2009)
Pumping Station Design, Robert L. Sanks, et al. (1989), Butterworths, Stancham, Massachusetts
Cameron Hydraulic Data, 18th edition, Liberty Corner, New Jersey
Pump Handbook, 4th edition, Igor J. Karassik, et a.l, McGraw-Hill Book Company, New York, New York
Design of Trench-Type Wet Wells for Pumping Stations, Robert Sanks, reviewed by Senon (May 2008 Pumps & Systems magazine)
Computation Fluid Dynamic Modeling of a Proposed Influent Pump Station, Wicklein, Sweeney, Senon, et al., WEFTEC 2006
Machinery Malfunction Diagnosis and Correction, Robert Eisenman, Hewlett-Packard Professional Books
Friction Factors for Non-Newtonian Fluids (Sludge), Design of Municipal Wastewater Treatment Plants, 4th Ed., WEF Manual of Practice 8, ASCE and Report on Engineering Practice No.76, Volume 3, Chapter 8: Solids Storage and Transport
Flow of Fluids Through Valves, Fittings and Pipes Crane Technical Paper No. 410. Page | Chapter 1-4
OCT 2011
1.4.2.
MWH Contacts NAME
TELEPHONE
E-MAIL
Constantino (Tino) Senon
Cell 425 421-6842 Direct 360 387-7851
[email protected]
Timur Ayvaz
Cell 713 501-6784 Direct 303 291-2124
[email protected]
George Tey
Direct 626 568-6259
[email protected]
Page | Chapter 1-5
OCT 2011
2.
DESIGN CRITERIA DEVELOPMENT
2.1.
General The following information is presented as a standard methodology in order to ensure consistent and accurate MWH designs. Information is presented in a sequence typically encountered during a design project.
2.1.1.
Client Preferences With every new project, MWH employees have the opportunity to work with multiple clients throughout the world. Each client has a unique perspective of their environment. As consultants we must listen to our Clients in order to ensure our Clients’ success. Many times, Clients have very specific preferences regarding the type of design, equipment used or how the system is controlled. These preferences could be based on a new direction the client is interested in pursuing, past experiences or even the level of local vendor support. In developing the design criteria, it is essential to first determine the Client’s preferences with regards to the project.
2.1.2.
Site Constraints A design engineer must also understand the site details surrounding the new or existing pump station. In some instances, there may be limitations influencing the design of the station. These constraints could range from geotechnical information, such as settlement, seismic requirements, flood elevation or high ground water to neighbors on adjacent properties. The design engineer should always be mindful of the environment the pump station is being constructed.
2.2.
Fluid Properties Determining the process fluids properties to define the fluid service and pump materials is the first step in developing the pump station design criteria. The properties of fluids which are of fundamental importance to the subject of the Guide are discussed in the following sections. These properties are specific gravity (based on density or specific weight), viscosity, temperature and corrosion and erosion potential.
2.2.1.
Specific Gravity The density of a substance is a measure of the concentration of matter, and is expressed in terms of mass per volume. The specific gravity is a term used to compare the density of a substance with the density of water. Because the density of liquids depends on temperature, the temperature of the liquid in question as well as the reference temperature of water should be stated in giving precise values of specific gravity. When dealing with fluids other than water, identifying the specific gravity is essential as it directly affects the pump station power demand. The power input (horsepower) of the pump is directly proportional to the specific gravity (S.G.) of the fluid. Therefore, if the horsepower for a pump conveying water (S.G. =1.0) is 100 HP, then a liquid with a specific gravity of 1.2 requires 120 HP. The following are two reference tables for the design engineer. Table 2-1 indicates the density of water with respect to temperatures. Table 2-2 identifies the specific gravity of typical fluids the design engineer may come across. More detailed information is available in the Cameron Hydraulic Data reference book.
Page | Chapter 2-1
OCT 2011
Table 2-1: Density of Water at Various Temperatures Temperature °F
Density (slugs/ft3)
Specific Weight (lb/ft3)
32
1.94
62.41
40
1.94
62.43
50
1.94
62.41
60
1.94
62.37
70
1.94
62.31
80
1.93
62.22
90
1.93
62.12
100
1.93
62.00
120
1.92
61.71
140
1.91
61.38
160
1.90
60.99
180
1.88
60.57
200
1.87
60.11
212
1.86
59.81
Table 2-2: Specific Gravity of Some Liquids at 60°F
2.2.2
Liquid
Specific Gravity
Gasoline
0.66-0.74
Kerosene
0.78-0.82
Sea Water
1.03
SAE Oils
0.88-0.94
100% Glycerin
1.26
Ethyl Alcohol
0.79
40% Caustic Soda
1.43
Mercury
13.57
Water
1.00
Viscosity Another major factor affecting pump behavior and system response is the fluid's viscosity, which is the fluid's resistance to shearing. Fluids differ from solids by continuing to deform in the presence of a shearing stress; when a shearing stress causes a liquid to flow, it continues to flow as long as the shear stress acts on it. Therefore, viscosity can also be defined as a fluid's resistance to flow. A general formula developed by Isaac Newton is:
μ Where = the shear stress exerted by the fluid (its "drag") µ = the fluid's viscosity (a constant of proportionality) = the velocity gradient perpendicular to the direction of shear
Page | Chapter 2-2
OCT 2011 Fluids which behave in the above manner are called Newtonian fluids, and continue to behave this way no matter how fast it is stirred or mixed. With a non-Newtonian fluid, on the other hand, stirring can leave a "hole" that gradually fills in over time, or cause the fluid to become thinner. The viscosity of a Newtonian fluid depends only on temperature, pressure and the chemical composition of the fluid. Therefore, for a given substance and pressure, these fluids have a straightline slope when plotting viscosity against temperature on the viscosity charts included in standard references. Non-Newtonian fluids are classified as thixotropic, dilatent, or rheopectic, depending on how the viscosity changes with respect to the rate of shear (see Figure 2-1). Of particular importance in wastewater engineering are thixotropic fluids, which include thick sludges and some chemical precipitants. A thixotropic fluid is one in which the viscosity decreases as the rate of shear increases (a characteristic of ketchup, difficult to start, but once started it is difficult to stop – shaking the bottle first "pre-shears" the ketchup, making it easier to pour).
VISCOSITY
Newtonian
thixotropic
SHEAR RATE Figure 2-1: Newtonian versus Thixotropic Materials The "pumpability" of a thickened sludge, dewatered sludge or a chemical precipitant depends on many factors and should be assessed by specialists in this type of pumping. In some cases, a representative sample of the fluid is sent to the laboratory for testing. Based on the test, the pumping design criteria can be established especially for mine slurry and sludge. Another good reference is Moyno Pumps by Robbins Meyers Company. They have compiled actual test data of different Newtonian fluids especially for sludge. In fact Moyno will test any sludge for a minimal fee. For this type of analysis, the design engineer should seek assistance from the Chief Mechanical Engineer. Viscosity is expressed as either dynamic or kinematic viscosity. The kinematic viscosity is the ratio of dynamic viscosity to density:
μ
Where = kinematic viscosity µ = dynamic viscosity = density As with specific gravity the viscosities effect on the pump performance. There are many guidelines and tables published to predict pump performance when pumping highly viscous solutions. The design engineer should seek assistance from the Chief Mechanical Engineer when dealing with viscous solutions. The following Figure predicts the affect of a viscous solution on the performance of a pump. The effect on pump performance is presented in the form of percentage changed as compared to pumping water. Page | Chapter 2-3
OCT 2011
Figure 2-2: Viscosity Corrections for Large Pumps Obtained from Cameron Hydraulic Data, 19th Edition
2.2.3.
Temperature The previous sections discuss the impact of specific gravity and viscosity on the pumping system. These properties are not always constant; temperature affects both the density (specific gravity) and viscosity of the pumped fluid. A design engineer must incorporate the affects of temperature in the hydraulic calculations especially if the process covers a wide range of temperatures greater than 68 F. Furthermore, temperatures may directly impact the Net Positive Suction Head (NPSH) for the pumps. (NPSH is discussed in greater detail in section 2.6.4). Hydraulically, for optimum pump performance, the pump requires a minimum amount of pressure at the eye of the impeller. This minimum pressure at the eye of the impeller is affected by the temperature of the solution. At higher temperatures, the vapor pressure of the fluid increases thereby decreasing the overall inlet pressure. The design engineer should always consider the fluid temperatures and vapor pressure when determining the NPSH available in a system. Temperature can also affect pump efficiency. Usually, pumps are tested at the factory using water at ambient temperature. If the test water temperature is higher or lower than the ambient temperature of approximately 50 F, the pump efficiency shall be corrected to ambient temperature. Conversely, if the test pressure is lower than the water temperature at field condition such as for hot water circulating service. The test efficiency should also be corrected to field condition. Refer to the Hydraulic Institute Standards, Rotodynamics Acceptance Test Criteria. When designing a system, certain materials or components are temperature dependent. The MWH Guide Specifications provides guidance in the form of Notes to Specifier when dealing with special considerations for high temperature applications. For example, Section 43 10 50, Piping General provides guidance on the selection of gaskets, couplings, connectors and other piping components for various temperature conditions.
Page | Chapter 2-4
OCT 2011
2.2.4.
Corrosion and Erosion Considerations The discussion presented in the previous sections considers the fluid property’s effect on the hydraulics of the pumping system. Corrosion and erosion are a fluid characteristic with no effect affect on the hydraulics, but if not considered may be detrimental to the life of pumps, valves and piping. The effects of corrosion and erosion should always be considered when dealing with fluids other than potable water. Corrosion is an undesirable degradation of material resulting from a chemical or physical reaction with the environment. Erosion is the deterioration of metals buffeted by the entrained solids in a corrosive medium. The corrosive or erosive potential of a service would dictate the materials of construction, hardness and ductility of material and special liners such as rubber are required. Figures below show an example of corrosion and erosion on the pump impeller.
Figure 2-3: Corrosion on Pump Impeller
Figure 2-4: Erosion on Pump Impeller The following is a brief list of potential corrosive services the design engineer may encounter. Note this list is a small excerpt of various corrosive services defined in the Pump Handbook by Igor Karrassik. When designing a pump station with a fluid containing corrosive constituents such as the Colorado River Water, water known to be corrosive, or fluids other than water, a sample must be taken and tested. Results should be reviewed by the corrosion engineer and the pump manufacturer Page | Chapter 2-5
OCT 2011 for proper material selection of pump components. An example of water constituent analysis is included in the MWH Guide Specifications for Pumps.
Common Corrosive Applications o
Sea Water
o
Water with high sulfides (hydrogen sulfide in wastewater)
o
Chemical Acids and bases with lower and higher pH
The following is commonly used terms the design engineer should be familiar with.
Erosion Corrosion – The deterioration of metals buffeted by the entrained solids in a corrosive medium. This corrosion also depends on flow angle of attack of liquid relative to the component
Abrasive wear – Erosion of any material as a result of the following suspended solids characteristics o
Solid concentration
o
Solid size and mass
o
Solids shape
o
Solid hardness
o
Relative velocity between solids and surface
Abrasive material – Suspended solids which contribute to abrasive wear such as grit and sand.
Cavitation erosion – Pumps experiencing inadequate NPSH margin, air entrainment, freesurface and sub-surface vortices are susceptible to cavitation erosion. Cavitation erosion is the degradation of the material surface due to cavitation. Pump materials resistance to cavitation erosion in increasing order are as follows: o
Cast iron (least resistant)
o
Bronze
o
Cast steel
o
Manganese bronze
o
Monel
o
400 Series stainless steel
o
300 Series stainless steel
o
Nickel-aluminum bronze
o
Ni-resist ductile iron ( Ni-Hard) (most resistant)
Corrosion Fatigue – Related to the endurance stress of material based on cyclic reversal of load applications.
Galvanic Corrosion – Galvanic corrosion occurs when two dissimilar materials are in contact or electrically connected in a corrosive medium. Corrosion of less noble material is accelerated and corrosion of more noble material is decreased.
Graphitization – In the presence of an electrolyte, a galvanic cell exists between the cast or ductile iron and the graphite particles. In the galvanic cell of iron and graphite, iron becomes the anode and the graphite becomes the cathode. A galvanic current flows from the iron to graphite; therefore, the iron goes into solution resulting in gradual depletion of iron until only graphite remains. While the casting appears sound on the outside, pieces may be broken off with the fingers.
Page | Chapter 2-6
OCT 2011
Concentration cell, or crevice, corrosion – When an electric current flows between two areas causing a localized attack. This usually occurs where water is stagnant, such as threads, gasket surfaces, holes, crevices, surface deposits and in the underside of bolts and rivet heads. When concentration of corrosion occurs, the concentration of metal ions or oxygen in the stagnant area is different from the concentration in the main body of the liquid.
Selective Leaching – Removal of one element of material from solid alloy in a corrosive medium such as the process of dezincification, dealuminumification, and graphitization. For example where a certain water source is known to have dezincification characteristics, low zinc bronze is normally recommended
Intergranular – Materials can look sound on the surface but intergranular corrosion can progress to a point that the material literally disintegrates. Intergranular corrosion of austenitic stainless steel occurs as a result of carbides precipitating out the grain boundaries during slow cooling of the casting.
Buried piping – Corrosive soils are a factor when designing buried piping systems. The geotechnical reports shall consider the overall corrosive properties of the soils, and recommend a method to mitigate its affect on the buried piping.
Corrosive Constituents in Municipal type Wastewater Systems When designing a wastewater pump station, the design engineer shall pay special attention to any air/wastewater surfaces. Anaerobic sulfate-reducing bacteria (such as Desulfovibrio) thrive in wastewater. This bacteria utilizes the oxygen in sulfate (commonly found in wastewater) to create hydrogen sulfide, which escapes from the wastewater to the atmosphere above. At that point, an aerobic bacteria (Thiobacillus) converts the hydrogen sulfide to sulfuric acid. Sulfuric acid is extremely corrosive whether it is concrete, steel or ductile iron. Process design should minimize hydraulic jumps, turbulence which could cause off-gassing of H2S. If off-gassing cannot be prevented by alternate design, materials resistant to H2S shall be specified such as 316 stainless steel. Iron Reducing Bacteria found in Deep Wells Iron reducing bacteria have been found in deep wells which corrode pumps components made of cast iron, ductile iron, carbon steel or even 304 stainless steel. Recommend using 316 stainless steel. During development of deep wells, a water sample shall be tested for its corrosivity and look for the presence of iron reducing bacteria as well.
Page | Chapter 2-7
OCT 2011
Table 2-3 Galvanic Series of Metals and Alloys
<<<<<<<<<<<<<<<<<<<<<<<<<<< GALVANIC SERIES >>>>>>>>>>>>>>>>>>>>>>>>>>>>
Sacrificial Anodes Magnesium Magnesium alloys Zinc Aluminum 2S Cadmium Aluminum 17ST Steel or iron Chromium stainless steel, 400 series (active) Austenitic nickel or nickel-copper cast iron alloy 18-8 Chromium-nickel stainless steel, Type 304 (active) 18-8-3 Chromium-nickel-molybdenum stainless steel, Type 316 (active) Lead-tin solders Lead Tin Nickel (active) Nickel-base alloy (active) Nickel-molybdenum-chromium-iron alloy (active) Brasses Copper Bronzes Copper-nickel alloy Nickel-copper alloy Silver solder Nickel (passive) Nickel-base alloy (passive) 18-8 Chromium-nickel stainless steel, Type 304 (passive) Chromium stainless steel, 400 series (passive) 18-8 Chromium-nickel-molybdenum stainless steel, Type 316 (passive) 18-8-3 Chromium-nickel-molybdenum stainless steel, Type 316 (passive) Nickel-moly Silver Graphite Gold Platinum Protected End (cathodic, or most noble)
Reprinted by courtesy of The International Nickel Company Inc.,67 Wall St., New York, NY Page | Chapter 2-8
OCT 2011
2.3.
Pump Station Configuration Unfortunately, no single pump station configuration fits every application. The design engineer is urged to review the pump station examples provided in this Guide as a starting point. If the required features do not closely resemble the examples, contact the Chief Mechanical Engineer or any of the persons listed in the contact list for any other examples. The type of pump station configuration varies greatly depending on different factors such as hydraulic considerations, Client’s preference, and the type of pumps, the control and maintenance expectations and the size of the station. The following sections provide a brief overview of the various types of pump station configurations available.
2.3.1.
Suction Configuration Depending on the hydraulics of the specific application, a variety of pump suction configurations may be used.
2.3.1.1.
Wet wells are typically used to provide storage volume or a hydraulic break. Typical pump stations which use wet wells are sewage lift station, treated water high service pump station, raw water booster pump station or submersible sewage pump station.
A “can” (also called a barrel) is typically used for a vertical turbine pump connected to an adjacent forebay or reservoir.
Piping manifold suction headers are typically used for horizontal centrifugal pumps stations connected to an adjacent forebay or reservoir. This configuration may also be used for inline booster pump stations. (Inline booster pump station is usually discouraged because it complicates the surge protection and controls)
Wet Well A wet well is a below-grade structure (above grade is possible, but not typical) of a pumping station. It is the structure into which the liquid flows from, and where the pumps draw water. The wet well serves three purposes. First, it creates a hydraulic break minimizing the effects of upstream system on the current system. The free water surface is allowed to rise and fall buffering the system from any fluctuations in flow and pressure. Second, it provides storage volume to allow constant speed pumps to start and stop without exceeding the number of starts required for a certain size motor. Third, it provides adequate submergence above the suction bell of pump to prevent formation of vortices and provide adequate Net Positive Suction Head (NPSH). Fourth, it provides free-board to allow the level to rise during upset or emergency operation without overflowing. Additionally, the wet well shall be configured to preclude formations of free-surface or subsurface vortices or prerotations that can be carried through the pump suction volute. At a minimum the wet well design shall meet the flow distribution based on the accepted criteria recommended by the Hydraulic Institute’s Intake Design Standard. These recommendations mitigate adverse hydraulic phenomenon that may occur in the pump station wet well. In summary, the geometry of the wet well, operation of the pumps, and the depth of water in the sump influence the approach flow hydrodynamics and can result in the following adverse hydraulic phenomena (Sweeney and Rockwell 1982):
Pre-swirl of flow approaching the pump impeller
Free surface vortex formation
Spatial asymmetry of the flow approaching the pump impeller
Temporal fluctuation (turbulence) in the flow approaching the pump impeller
Air Entrainment
Page | Chapter 2-9
OCT 2011 The following section describes typical wet well configurations used by MWH. The appendix includes example drawings of these configurations.
Rectangular with flat bottom used for clean water application such as treated water high service pump stations, and potable water storage reservoirs.
Rectangular with hopper bottom used for solids bearing fluids such as raw sewage, grit chamber, sludge, raw water, etc.
Rectangular with sloped bottom and flow distribution inlet channel for sewage and sludge pump stations. Refer to Wet Well Design Guide for Large Submersible Pumps by ITT Flygt Pump.
Open-trench Type wet well with an Ogee weir for liquids bearing solids especially raw unscreened municipal sewage.
For design guides, refer to the following references:
ANSI 9.6-1998 HI Pump Intake,
Design of Trench-Type Wet Wells for Pumping Stations, Robert Sanks, reviewed by Constantino Senon (May 2008 Pumps & Systems magazine)
Computational Fluid Dynamic Modelling of a Proposed Influent Pump Station, Wicklein, Sweeney, Senon, et al., WEFTEC 2006
MWH exceptions and improvements to HI recommendations based on lessons learned from Durham and Tacoma IPS. For list of exceptions, refer to Computational Fluid Dynamic Modeling of a Proposed Influent Pump Station, Wicklein, Sweeney, Senon, et al., WEFTEC 2006. For detailed drawings, refer to example drawings from Durham and Tacoma IPS.
Use minimum submergence S=4x suction bell diameter “D” or greater.
Use long radius suction elbow with flare bottom.
Provide flow straightening device downstream of the suction elbow
Use long radius reducing elbow to connect the horizontal suction pipe to the pump suction.
When is Physical Hydraulic Model Study Required? A physical hydraulic model study can be expensive, but in many cases will provide insight into specific hydraulic issues that may adversely affect the pump station. Based on ANSI/HI 9.8-1998, the Hydraulic Institute Standards recommend physical model testing if one or more of the following features exist in the project:
Sump or piping geometry deviates from the intake design standards.
Non-uniform or non-symmetric approach flow to the pump sump exists.
Pumps have flows greater than 2520 l/s (40,000 gpm) per pump or the total suction flow with all pumps running would be greater than 6310 l/s (100,000 gpm).
Pumps with an open bottom barrel or riser arrangement with flow greater than 315 l/s (5,000 gpm) per pump.
Proper pump operation is critical and pump repair, remediation of a poor design, and the impacts of inadequate performance or pump failure all together would cost more than ten times the cost of model study.
When is the Computational Fluid Dynamics (CFD) Study Required? The computational fluid dynamics study could be performed as a pre-requisite to the physical model study for the following reasons:
The CFD model is less expensive as the physical model study.
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OCT 2011
The CFD model can be used to optimize the wet well design for least cost. The model can be revised easily in the computer and operational flow scenarios can be simulated without the need to modify fabricated physical model.
Although the result of the CFD model have not been endorsed by HI as a substitute to the physical model because of the accuracy of the software available in the market, MWH experience indicate that if the result of the CFD model is gauged against the HI acceptance criteria used for physical model, the result of CFD model could be conclusive in lieu of conducting physical model study if approved by the Senior CFD modeller and Chief Mechanical Engineer. The approval criteria shall be based from previous experience of similar wet well configuration that had been proven to work.
An example of the CFD Study of the wet well configuration that demonstrate non-conformance to the HI acceptance criteria is shown in Figure 2-5 below. This wet well was an existing wet well designed by another consulting engineering firm and it is in the process of being modified by MWH using physical model test.
Figure 2-5 Example CFD Study of a Wet Well Configuration with Flow Distribution Deficiency
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OCT 2011 MWH has taken exception to the HI guidelines regarding when to perform a CFD or physical model study under the following circumstances. If the wet well design is identical in flow, wet well configuration with a pump station that has been previously modeled, constructed and have a record of successful operating experience such as the Durham IPS and City of Tacoma IPS, etc., a physical hydraulic model test may not be required. Please contact the Chief Mechanical Engineer for the additional list of projects. Example of a physical model is shown in Figure 2-6.
Figure 2-6 Example Physical Model What is Model Performance Acceptance Criteria The Hydraulic Institute Standards established criteria for evaluating performance of pump station designs through the use of physical model studies. ANSI/HI 9.8-1988 details the physical modeling procedures and the interpretation of the results. The following is a list of minimum performance criteria for a physical model:
Free surface and subsurface vortices entering the pump must be less severe than vortices with coherent (dye) cores (free surface vortices of Type 3 and sub-surface vortices of Type 2 – from HI 9.856). Dye core vortices may be acceptable only if they occur for less than 10% of the time or only for infrequent pump operating conditions.
Swirl angles, both short-term and long term as defined in the Standard.
Time-averaged velocities at points in the throat of the bell or at the pump suction in a piping system shall be within 10% of the cross-sectional area average velocity as defined in the Standard.
For special case pumps with double suction impellers, distribution of flow at the pump suction flange shall provide equal flows to each side of the pump within 3% of the total flow.
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OCT 2011 2.3.1.2.
Design Considerations The wet well or forebay volume should be designed with adequate storage to prevent frequent starting and stopping of the pump. This starting and stopping is called cycling of the pumps. The maximum number of allowable starts is typically dependent on the characteristics of the electric motors and typically ranges between 6 for large motors and 15 for small motors. The design engineer is responsible for contacting the pump/motor manufacturer to obtain the minimum cycle time. Furthermore, the wet-well should be sized to allow for the pump starting sequence. The starting sequence usually takes between one to three minutes, depending on the required opening and closing time of the pump control valves. The opening and closing delays may be field adjusted to prevent extended operation of the pumps between shut off and operating duty point. The starting and stopping times for pumping units equipped with check valves, is usually less than a minute. The wet well should be sized to provide adequate storage during this time period. For multiple-speed pumps, the available storage volume in the wet well does not need to be as conservative. As flow rate is controlled by the speed of the pump, the pump does not need to start against a closed valve. The pumps can start, and increase speed to immediately contribute flow into the system. One design criteria often overlooked is the storage volume required in the event of a power out-age. With a constant flow rate entering the pump station wet well, a disruption in local power will immediately be reflected with a rise in the water surface elevation as in the case of booster pumps in series. In this example, it is impossible to provide storage for an extended power outage. Therefore, the SCADA system shall be configured such that in the event of power failure in a downstream pump station, the upstream pump station shall be signaled to stop. In collection system applications, the flow can be allowed to back-up into the system, otherwise the wet well should be designed with adequate storage volume or overflow potential during a power outage. The design engineer shall review the local codes and client’s preferences regarding the design power outage duration. Most state regulatory agencies in the US include maximum retention time in the wet well design criteria, when pumping wastewater. The intent is to minimize the potential for the development of septic conditions and resultant odors. A maximum retention time of 10 minutes, at average design flow rates is often quoted. Unfortunately, this requirement may conflict with the need for adequate volume to prevent short-cycling of the pumps. In such cases, multiple pumps or variable-speed pumps should be considered to reduce the required volume. Furthermore, in addition to minimizing retention times, odors can be minimized if the lowest liquid level in the well is set above the sloping portion of the wet well. This can be accomplished by making this level the stop point for the lead pump in the sequence. For Sizing of Wet well or sump Volume, refer to HI Pump Intake Design, Appendix B
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OCT 2011
Figure 2-7: Hydraulic Institute Wet Well Volume Calculation Procedure
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OCT 2011 When designing the wet well, the design engineer shall consider the following:
2.3.2.
Provide an opening in the deck with adequate clearance to allow removal of any pump components or piping from the wet well.
The wet well shall be provided with an air vent sized to release or admit outside air due to the rise and fall in water levels. Area of vent is typically equal to at least half of the inlet pipes area this dimension is a minimum, the required dimension may be larger. For se-wage or sludge pump station, vent pipe shall be connected to the foul air scrubber
Provide a hatchway for access to the wet well. Hatchway size to be at least 4 ft by 4 ft with appropriately sized safety net or equivalent safety system.
Permanent ladders shall NOT be included in the wet well due to corrosion and the potential safety concerns.
Address Confined Space requirement and fire and safety requirement per NFPA 820. Consult the MWH HVAC Lead Engineer.
Dry Well or Dry Pit As mentioned previously, pumps draw water from the wet well. Locating the pump adjacent to the wet well minimizes the suction losses. The pump would need to be installed below the water surface elevation. To accomplish this, a second structure is installed adjacent to the wet well. This below grade structure, called a dry well, contains the pumps, drive shafts, valves and piping. For this configuration, there is no liquid surrounding the pump and valves, therefore the equipment are accessible for maintenance. This maintenance accessibility is the main advantage of the dry well configuration.
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OCT 2011
Figure 2-8: Typical Dry Well Configurations
2.3.3.
Submersible Pump Station Another type of pump station configuration typically used for sewage lift stations is a submersible pump station. A submersible pump station does not have a dry well. The pump and piping is located within the wet well. The pump and motors is specially designed for submergence in the water or wastewater.
Figure 2-9: Typical Submersible Pump Station Page | Chapter 2-16
OCT 2011 The advantage of this type of station is cost. The overall building footprint is much smaller than a dry pit station. Furthermore, the entire pump station, excluding electrical panels and SCADA system, can be located below grade, which might have its advantages if the pump station is located in a visually sensitive area. Unless otherwise preferred by the Client, MWH’s preference regarding when to utilize a submersible configuration versus a dry well configuration is related to the pump horsepower. For pumping stations equipped with pumps sized up to 700 HP the installation costs of a submersible pumping system is normally less than the dry well pumping systems because the pumps can be installed without the need of building a dry pit. However for larger installations with pumps larger than1, 000 hp, a dry-pit pumping system is preferred by most Clients because it is easier to inspect and maintain. Dry pit pumping systems; however have a risk of being flooded. The clients’ policies and/or preferences should be given careful consideration. For small manhole type sewage lift stations, submersible pumping system offer advantages over drypit systems because they are less expensive to build and they are also available from the manufacturer as a package unit. The manufacturers are Smith and Loveless and Gorman-Rupp. Submersible pump stations can be installed underground, below streets, or in a limited space by the roadside with the motor control panel mounted above ground.
2.3.4.
Vertical Turbine Installations Vertical turbine pumps are typically suspended from the structure, with only the pump unit (bowl assembly) submerged below the water surface. The motor is typically installed above a wet well or above ground and supported by the discharge head. Vertical turbine pumps can also be installed inside the can or barrel. Barrel mounted vertical turbine pumps are highly sensitive to the intake hydraulics. The vertical turbine pumps are classified into three types based on their specific speed; bowl assembly and impellers.
Radial and Francis-Vane turbine impeller [Ns: 500 to 4000] – enclosed or open type, multi-stage, low flow high head
Mixed flow impeller [Ns: 4500 to 8000] –enclosed or open type, maximum two stage, medium flow, medium head
Axial/propeller flow impeller [Ns: 8000 to 15000] – open type, maximum single stage, high flow, low head
Figure 2-10: Typical Vertical Turbine Pump Installation Vertical turbine pumps are sensitive to intake design configuration, including submergence over the 1st stage impeller, spacing between two adjacent pumps or the wall; and spacing from the bottom of Page | Chapter 2-17
OCT 2011 the pump to the floor. Complying with these requirements mitigates vortices, and a wet well designed to establish uniform flow velocity distribution at the suction bell. Uneven velocity distribution, compounded by insufficient submergence can result in the formation of vortices which may introduce air into the pump suction causing a reduction in capacity, unbalanced impeller loading, rough operation or impeller damage due to cavitation. For vertical turbine pump intake design guidelines, refer to the Hydraulic Institute Standards. For submergence over the bell requirements, refer to the pump manufacturer’s published performance curves and pump data. Design Considerations When mounting vertical turbine above a wet well, the design engineer shall consider the following requirements:
The top structure of the wet well shall be designed for the maximum down thrust generated from pumping the liquid. The down thrust generated by the pump is absorbed by the motor top bearing and transferred to the structure. The pump thrust information is available from the pump manufacturer. Thrust factor is normally indicated on the pump performance data sheet in terms of pounds per foot of head.
The top deck should be designed so that the natural frequency is at least two times the maximum speed of the pump. The design engineer shall coordinate design with the structural engineer.
Pump pads should be designed integral with the top of the wet well deck.
Location of piping and valves for access needs to be coordinated with the tank and nearby area.
For pump stations with flow rates in excess of 5,000 gpm, provide isolation baffles between the pumps.
Provide adequate submergence over the suction bell to prevent vortexing at low water level, create NPSH available greater than what is required by the pump, avoid cycling on/ off pump operation and free board above high water level. Provide NPSH margin of at least 5 feet absolute. Minimum submergence shall be equal to or greater than the pump manufacturer’s recommendation.
Note to Design Engineer: The terms minimum submergence and NPSHr refer to two separate items. Minimum submergence is the minimum water level required regardless of NPSHr. It is the Design Engineer’s responsibility to ensure that requirements are met.
Provide a combination air release and vacuum valve mounted on the discharge pipe located between the pump discharge and the check valve. Size air valve using APCO valve calculator.
Provide opening in deck with adequate clearance to allow removal of pump assembly. Use the maximum diameter of the column pipe flange, bowl assembly or suction bell whichever is the largest.
Wet well shall be provided with an air vent sized to release or admit outside air due to the rise and fall in water levels. The area of vent is usually equal to at least half of the area of inlet pipe. Provide a hatchway for access to the wet well. Hatchway size to be at least 4 ft by 4 ft with appropriately sized safety net or equivalent safety system. Design engineer shall also consider potential debris removal when sizing and locating hatches.
For wastewater pump stations, permanent ladders shall NOT be included due to corrosion and create a potential safety concerns.
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OCT 2011
When using a vertical turbine installed in a barrel/can, the design engineer shall consider the following requirements:
The annular velocity between the inside diameter of the barrel and the pump shall be between 3 to 5 fps. The annular velocity shall be calculated using the maximum flow for each pump. This size should be confirmed with the manufacturer requirements for the selected model.
MWH’s exception to HI design criteria. The vertical distance from the centerline of the inlet pipe to the barrel to the suction bell shall be at a minimum 3 to 4 times the diameter of the barrel instead of 2 times the diameter of the barrel per HI. MWH exceptions are annotated in Figure 212.
Pump foundation or inertia base should be designed with a mass equal to or greater than 4 times the weight of the motor or adequate to support the pump and motor assembly whichever is the largest. Pump foundations shall be isolated from the concrete area or floor of the building. This design will limit transferring vibrations to the slab or building. Any exceptions shall be brought to the Chief Mechanical Engineer attention.
Calculate hydraulic grade line at the pump suction with friction loss based from the maximum pump flow. The hydraulic grade line at the centerline of the pump shall be at least: o
One diameter higher than the crown of the inlet pipe
o
Net Positive Suction Head Available (NPSHa) referenced to the datum of the pump shall be calculated using the hydraulic grade line inside the barrel, including friction loss through the annular space between the pump and the barrel. Figure 2-11: Excerpt from Hydraulic Institute Intake Design Various Vertical Turbine Intakes
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OCT 2011
Figure 2-12: Excerpt from Hydraulic Institute Intake Design Vertical Turbine Can/Barrel Pumps
Figure 2-13: Suction and Discharge Piping for Vertical Turbine Can/Barrel Pumps
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OCT 2011
2.3.5.
Hydraulic Institute Self-Cleaning Wet Well (Trench Type) The self cleaning wet well design can be used for wastewater or solids bearing fluids with end suction, non-clog pumps. Vertical turbine or submersible type pumps have been used by other consultant and they have been known to have problems with flow distribution and stringy materials depositing around the pump column and slide rails and cables in the case of submersible pumps especially for unscreened and wider screen spacing. Trench type wet wells were developed based on the philosophy that variable speed pumps do not require significant wet well storage volumes. The speed of the pump can be adjusted using a Variable Frequency Drive (VFD) to maintain a constant water level (water entering the wet well equals the water leaving the wet well) thereby minimizing the time the fluid is in the wet well. Over the years, this concept has progressed through much iteration in the design. The most current design shown in Figure 2-12 is obtained from the Hydraulic Institute Intake Design Guidelines. MWH exceptions are annotated within the figure.
Figure 2-14: Open Trench Type Wet Well, Hydraulic Institute Standards, ANSI/HI 9.8-1998 The two main benefits of the open trench wet well design are minimizing wet well storage volume and the ability to convey solids without the need to have varying water surface elevations for pump control. This feature results in a compact pump station design. With regards to the ability to convey solids, the operational guidelines for this type of wet well includes a cleaning cycle in which the water surface elevation is lowered. The influent flow cascades down the “ogee” weir at the entrance of the Page | Chapter 2-21
OCT 2011 wet well. The cascading flow accelerates, with the flow velocity reaching a scouring velocity removing settlement and debris from the bottom of the wet well. The solids become suspended, enter the pump and are conveyed downstream. Self cleaning wet well design should be provided for sewage pumping stations as indicated within Hydraulic Institute Standards. MWH’s previous experience has taken exception to the minimum submergence over the suction bell of 2 times pump bell diameter. The design engineer shall use 4 times pump bell diameter for the minimum submergence. In the three models performed, submergence of 2D or as calculated using Froude’s equation, any turbulence in the water surface is carried to the pump suction bell. However using a submergence of 4 times D, when the wet well was drawn down to the operating low water level, the flow entering the suction bell was not affected by any turbulence in the surface.
2.3.6.
Forebay / Reservoir Pump Station Wet wells are typically used to create hydraulic breaks between two separate systems. In water distribution or conveyance systems, the wet wells or reservoirs are required to handle large variations in flow so that the pumps can be controlled by level and/or flow. The wet well or reservoir shall be designed with a storage volume for the following:
The storage volume at the bottom of the wet well or reservoir shall provide adequate submergence over the pump suction bell or adequate NPSH margin over the pump datum.
The storage volume at the middle shall provide adequate level or dead band to control the pumps preventing it from cycling motor that the number of starts per hour as recommended by the motor manufacturer.
The top storage volume shall provide free board to prevent the wet well or reservoir from over flowing in the event of abnormal operation. The volume shall also be adequate to allow w all of the pumps to stop during abnormal condition without overflowing.
As a result, it becomes advantageous to store large volumes of water upstream of the pump station. The pump station must rely on a forebay or reservoir as the source of water for the pump station. The forebays or reservoirs are typically above ground concrete structures used for storage of large volumes of water. The forebay/reservoir pump station arrangement can be used with horizontal end suction, split case pumps or vertical turbine pumps. The design engineer shall use MWH Best Practices for designing reservoirs.
FOREBAY
PUMP STATION
Figure 2-15: Aurora Forebay/Reservoir and Pump Station Page | Chapter 2-22
OCT 2011
2.3.7.
Industry Standards and Guidelines The following sections identify commonly used design guides in the water/wastewater industry. The design engineer should be familiar with these standards.
2.3.7.1.
Hydraulic Institute Intake Design Guide The Hydraulic Institute Standards were established to promote the continued growth and well-being of pump manufacturers and further the interests of the public in the areas of pumping systems. It is a collection of best practices when designing pumping systems. The guide covers topics ranging from pump placement in wet wells to maximum and minimum velocities in the flow stream. The use of the HI Standard is voluntary and the Design Engineer (Engineer of Record) is responsible for his design and therefore shall use his or her engineering judgment in using this Standard. As a minimum, MWH designs shall use the Hydraulic Institute Intake Design Guidelines where ever applicable to the project. The design engineer should be very familiar with the technical content in the guide.
2.3.7.2.
Flygt Design Recommendation Guides The design engineer is not always required to develop a wet well design from scratch. Not only are guidelines a useful resource, but under certain circumstances templates are available to aid the design engineer. ITT Flygt is a pump manufacturer who invested a significant amount of time in developing, verifying by Computation Fluid Dynamic (CFD) Models and physical model testing wet well designs. Flygt has developed design guides and templates for large submersible and axial flow pump installations. Although HI has not endorsed the Flygt design guides, these are industry accepted design methods. The HI Standard Committee has agreed to include it as a reference attached to the appendix of the Hydraulic Institute Standards. MWH has used the Flygt design guide in many successful wastewater installation. The Flygt guide includes a table which relates the individual pump capacities to various dimensions in the wet well. The two templates developed by Flygt are Pump Stations with Large Submersible Centrifugal Pumps and PL Pump Station Design Guidelines. The following is a link to the Flygt website: http://www.flygtus.com/
2.3.7.2.1.1. Pumping Stations with Large Submersible Centrifugal Pumps
This design guide identifies key dimensions for the wet well, and correlates these dimensions to the individual pump capacity. The design engineer should review footnotes in the design guide concerning appropriateness of use. There are known limitations of the design with regards to overall capacity and number of pumps. The Flygt pump station design guide utilizes a baffle region in the wet well with ports aligned with each individual pump. The influent line conveys flow into a baffled region, directing it downward along the finished floor towards the pump intakes. The intent on the design is not only to align the flow through the ports with the centerline of the pumps and mitigate short circuiting, but to increase the velocity along the finished floor. The higher velocities along the bottom of the wet well scour solids from the floor. In some instances, the design may call for the ability to take half of the wet well off line for cleaning or maintenance. In this type of situation, it is necessary to connect two adjacent wet wells using a slide gate. The main advantage of this configuration is to allow one wet well to be taken off line while other station remains fully operational. If the design calls for two wet wells to be joined, the connection point shall be in the baffle area of the wet well or upstream of the baffle area. Positioning the slide gate in the baffle area, or upstream of the baffle, minimizes the extent of cross flow at the pump intake. For any deviations from the design guide, no matter how minor, the design engineer shall consult the MWH Chief Mechanical Engineer. The concern is small changes (which may seem minor), could potentially have hydraulic ramifications to the design. For example, the port openings at the base of the baffle should have a velocity for 7 to 10 ft/sec and, subsequently, large head losses. If the design Page | Chapter 2-23
OCT 2011 engineer is concerned the velocity is too high, he or she may incorporate larger openings. To the design engineer, it may be a small change, however hydraulically the high head loss is beneficial and helps to ensure even flow distribution between the ports. Increasing the size of the ports is actually detrimental to the pump station. MWH has in-house capabilities to perform Computational Fluid Dynamic (CFD) simulations. Any wet well design which deviates from a recognized wet well design guideline shall be verified using CFD Modeling. The design engineer shall seek advice from the Chief Mechanical Engineer and Hydraulic Specialist if a CFD Model is appropriate. Figure 2-16. Includes images of the various configurations included in the Flygt design guide.
Figure 2-16: Excerpt from Flygt Design Guide Pump Stations with Large Submersible Centrifugal Pumps
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OCT 2011
The radial type wet well shown to the left has been used in the past in wastewater systems. To our knowledge, the pump station worked well. The main complaint was that this design was difficult to isolation individual flow to one side. If this configuration is to be used, a dual wet well is recommended.
Figure 2-17: Excerpt from Flygt Design Guide Pump Stations with Large Submersible Centrifugal Pumps 2.3.7.2.2.
Propeller (PL) Pump Station Design General Principles
In addition to the design guide for large submersible pumps, Flygt also publishes a design guide for submersible propeller pumps. The submersible propeller pump is a high flow – low head vertically suspended pump. The PL designation is a Flygt sales code for: P: Multi-blade propeller pump with bowl assembly, bell-mouth and outlet cone, for large capacity pumping of clean liquids. L: Semi-permanent vertical installation in large diameter discharge column made of steel or concrete. Typically this type of arrangement is used for flood control applications. The pump and motor are inserted into a pipe or caisson and submerged below the water surface. The discharge from the propeller is conveyed over the exterior of the motor, and then vertically to the discharge fitting at the surface.
Figure 2-18: Submersible Propeller Pump Propeller pumps are more sensitive to inlet flow disturbances relative to other pumps. Ideally the flow at the pump inlet should be uniform and steady without swirl, vortices or entrained air. To aid the design engineer in creating ideal hydraulics at the suction of the pump, Flygt developed the PL Pump Station Design General Principles. The recommendations presented in the design guide utilize established principles of hydraulic design obtained from the Hydraulic Institute Standards. The guide Page | Chapter 2-25
OCT 2011 also includes design information based on model and full scale tests, specific to propeller pumps, conducted by Flygt. The guide provides the design engineer a reliable hydraulic configuration for this type of pump. CAUTION: The design engineer shall request Flygt to review the design. If possible, request Flygt to verify by CFD simulation at no or minimal cost. CFD Model can also be prepared by our MWH specialist. The Flygt design is typically suited for their pumps. If an or equal is required on the project, the design engineer must indicate on the drawing that the pump manufacturer shall verify the intake design configuration and recommend to the engineer any modifications required to suit the or equal pump. The Flygt guide is a combination of narratives describing the various wet well configurations and dimensional drawings. The following text and images were obtained from the Flygt guide. The exact dimensions for each configuration are not included. The design engineer shall refer to the Flygt PL Pump Station Design General Principles for more information. The designs are divided into three configurations “A”, “B” and “C”. Configuration “A” – Standard Open Sump This configuration is the simplest to build and is often the first alternative considered. However, as it requires more submergence and possibly a longer approach than other configurations, the total cost of the station may be higher than other options.
Figure 2-19: Configuration A with Plain Intake or Vortex Cone and Swirl Plate
Figure 2-20: Configuration A with Intake Modifications for Asymmetrical Flows Configuration “B” – Compact Closed Intake This type of configuration is typically constructed of concrete or steel. The geometric features, like the curvature of the front wall, the corner fillets and the benching at the back wall, have been developed to allow smooth acceleration and turning as the flow enters the pump. Page | Chapter 2-26
OCT 2011
Figure 2-21: Configuration B With Concrete Construction Configuration “C” – A Closed Intake of the Draft-Tube Type This type of configuration utilizes a draft-tube intake, (also called a formed suction intake) and can be constructed of either steel or concrete. The intake reduces inconsistencies and swirl in the approaching flow. This intake is more effective than Configuration “B” because the sloping front wall is designed to minimize stagnation of the surface flow. The geometrical features of this intake provide for smooth acceleration and turning as the flow enters the pump. The minimum inlet submergence should not be less than 1xD.
Figure 2-22: Configuration C Closed Intake with Draft Tube
2.3.8.
Hydraulic Intake Design Intakes are considered to be an integral part of “pumping facilities”. Intakes vary in design, requiring special knowledge and expertise. A comprehensive discussion of intake layouts is beyond the scope of this Guide. This section is meant only to introduce the topic to the design engineer. Intakes include necessary structures located within a lake, reservoir, river, stream, canal or other body of water. The structures are inlet points for the pump station, and serve to minimize hydraulic disturbance and/or attempt to prohibit debris from entering the suction pipe. Pumping equipment may be mounted directly on the intake structure or may be located some distance away on dry land. When intakes provide a supply to remotely located pumps, the conveyance between the intake and pumps must be designed for gravity flow.
Page | Chapter 2-27
OCT 2011 In large bodies of water the actual intake may be located some distance from the shore. The intake should be located at a sufficient distance from shore (or edge of the reservoir) to assure adequate submergence under all anticipated seasonal and cyclic conditions. Frequently water quality considerations or ice influence the depth and/or distance from the shore. Potential damage of submerged intakes (by vandalism and anchors) needs to be considered if the area is used for recreational activities. The simplest intake consists of a screened pipe or concrete box, which supplies a pipeline extending to the pumping stations. Where the body of water is deep (more than 30 ft), and may experience seasonal turnover, a tower may be constructed with valve or gated intake ports to enable selection of the best quality water. The tower may also serve as the suction sump for vertical pumps. The latter requires a bridge, floats or other means for the discharge piping and electrical equipment to reach shore. In some lake intakes, fish screens are required. If fish screens are required, consult our fish screens expert in the MWH US Seattle Office. Example of a lake intake design at Lake Meade, Lake Powell and Morse Lake is shown in Figure 2-23.
Figure 2-23: Example Lake Intake Design
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OCT 2011
2.4.
Preliminary Design, Equipment and Piping Layout The design engineer shall follow the design and quality review requirement in the MWH Delivery Framework. In summary, the delivery framework consists of a list of activities and tasks required to implement a project from the preliminary design phase through detailed design and construction document development. The delivery framework requires the design engineer to follow the steps in chronological order to enhance efficiency, accuracy, avoid rework to meet quality, budget and schedule. Once the Client and MWH have selected a specific pump station configuration, the design engineer shall develop a preliminary piping layout. The preliminary piping layout shall be thoroughly developed as it directs further work by Structural, Architectural and Civil disciplines with respect to the overall building size. Future changes in the piping layout could result in a ripple effect through other disciplines forcing hours of additional rework. As a minimum, the design engineer shall comply with the piping layout guidelines identified in the Hydraulic Institute Standards and within this guide. The first step in defining the piping layout is to determine the total number of pumps. The number of pumping units and operating range of each pump is partially defined by the minimum and maximum capacities required by the pump station. The combination of pumps in the pump system must be capable of covering the entire range of required operational conditions. The Engineer shall identify the minimum pump station flow and the maximum flow at full build out. Providing a system which covers this range is a critical component of the design criteria. If the lower flow and head range is beyond the operating range of the main pump(s), a small “jockey” pump may be required. The jockey pump would operate at low flow and low head conditions. The design point of the jockey pump should be determined such that the flow and head range will slightly overlap with the operational envelope of the first large system pump. Once the quantity of pumps is defined, the design engineer shall proceed with designing the piping layout. The design engineer shall determine the following as part of the preliminary piping layout.
2.4.1.
Flow, TDH, horsepower, speed
System head curve and pump curve operating envelope
Type and number of pumps
Define characteristics of fluids, temperature, specific gravity, and fluids constituents
Identify corrosivity of fluid
Pump, valves and piping material selection
The system boundary for the piping layout.
Size of the suction and discharge piping.
Pressure rating of the piping and valves
Pipe materials of construction
Types of valves
Select ancillary equipment such as air compressors, HVAC, electrical rooms
Hydraulics Before commencing on hydraulic calculations, basic criteria should be summarized. The design engineer must know the full range of conditions that will be expected of the pumping facility. The following criteria should be obtained and summarized;
Maximum design capacity including the estimated seasonal, daily (or hourly rates) and other aspects of flow patterns.
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OCT 2011
The minimum required plant capacity including whether or not such flows need to be intermittent or continuous and the estimated percentage of the time that minimum or low flows may persist.
Future and/or estimated ultimate flows.
Where applicable, determine the pump station flow for which the pumps will operate most of the time or exceedence flow. For example, a sewage pump station in a collection system is to be designed for 200 MGD, but the 90% exceedence flow would be approximately 24 MGD.
The range of pressure or water levels that may be available on the suction side of the facility
The discharge conditions including the range of pressure and/or levels, that may exist at discharge locations
Details of existing (or proposed) discharge piping including materials, pressure rating, age, condition, diameters, layout lengths, valves and fittings.
Figure 2-24: Example Exceedance Curve
In most cases, the degree of accuracy required for computation of friction losses (and static heads) in pumping systems needs to be in the range of plus or minus 2 percent. If losses thru valves and fittings are not computed, include an allowance for minor losses and velocity head in the range of 2 to 4 percent of calculated pipeline friction, depending on the complexity of the discharge piping. For low lift applications (total pumping heads of less than 60 ft) minor losses (including velocity heads) may be a significant portion of total pumping head and need to be individually calculated. If information on discharge system dynamic losses is available from actual field tests and/or other hydraulic analyses, it should be scrutinized and if representative utilized in preference to computed data. It is important to note, that total dynamic head estimates are frequency over-estimated. A rare or extreme condition should not be the basis of design. There is a tendency to use conservative friction factors in computing dynamic losses in pumping systems, particularly transmission mains. Overly conservative assumptions should be avoided because they may result in misapplication of pumping equipment. Always use realistic and applicable assumptions and confirm with in-house advice. Use hydraulic data that you are familiar with. Hazen-Williams, Manning and Darcy-Weisbach/Colebrook formulas are all applicable. For water and wastewater friction loss calculation, use Hazen-Williams equation with C-factor per AWWA M-11. For viscous fluids such as chemical solutions, water and wastewater with velocity greater than 10 fps, use Darcy-Weisbach/Colebrook equation. 2.4.1.1.
Pump Station Capacity Considerations The design capacity of pumping facilities should be based on detailed investigations and projections. For most municipal applications, the station infrastructure such as buildings, embedded pipes and Page | Chapter 2-30
OCT 2011 electrical conduits will have a design life of more than 50 to 75 years and equipment can be replaced every 25 years. It may be appropriate to design the facility so that it could be expanded to meet anticipated demands of a 50 to 75-year planning period. Wastewater pumping stations and certain water applications may need to be designed to meet projected peak hour demands. Other water pump stations may be designed to meet estimated maximum-day demands. It is necessary to be familiar with the rationale of how the proposed plant capacity was determined and to be sure that it is appropriate and objective. It is also necessary to know what changes may be proposed on the discharge side of the pumping station in the future. Future pipeline improvements within a distribution system, for example, can significantly influence head (and capacity) of a pump station. The design criteria for the pump station should be shown on the design drawings. The criteria should show initial and future pump station capacity, number of units at each stage of development, key piping diameters, nominal velocity in suction and discharge piping, maximum operating pressure and motor ratings. For storm water pumping stations there are significant risks and exposure. All assumptions that were made to estimate peak flows need to be confirmed and indicated on a design criteria sheet that is part of the contract drawings. Key criteria should be listed such as:
Design storm frequency
Rainfall intensity
Watershed area
Runoff coefficient
Percentage impervious area
Storage basin capacity
Basin operating levels
If there is uncertainty due to such variables as rainfall intensity or demand forecasting assumptions, such uncertainties should be exposed and discussed with the client. Frequently the agreed solution is to provide for staged construction. The design criteria and other data on the drawings should clearly indicate if future stages were assumed. The criteria sheet should be signed by a responsible person representing the client. Be cautious in adopting past designs and criteria, for both wastewater and treated (potable) water. In the past, temporary overflows from wet wells or forebays, due to short term power out-ages may have been acceptable. Currently in the US, however, releases of untreated wastewater (or even disinfected potable water) due to negligence, including deficient designs can result in legal action and criminal charges. It is imperative that all foreseeable conditions and events should be considered to ensure that inadequate station capacity or design deficiencies will not result in releases. Once the design capacity of a pump station is established, subsequent steps should ensure that the capacity can be delivered by the proposed pump station with at least one pumping unit off line. For water pumping stations that directly serve a distribution area, the capacity determination (on whether the pump station capacity should be based on peak hour or maximum day projections) is related to the capacity of on-line service reservoirs and/or elevated storage. It will be necessary to confirm that there is sufficient storage to provide for peak hour demands and fire requirements.
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OCT 2011 2.4.1.2.
Total Dynamic Head Total dynamic head under a given flow is the sum of
Static lift
Friction head
Velocity head
Static head is the difference in elevation between the water level (or equivalent hydraulic grade line) on the suction side of a pump and the level on the discharge side. It is a measured or estimated under zero flow (static) conditions. Friction head is the sum of losses due to friction in suction and discharge piping and valves and fittings. For most applications it needs only be computed for one flow condition and at other flow conditions it can be estimated by assuming that total friction is proportional to flow squared. Velocity head is the energy required to move liquid. It is equivalent to V2/2g. It usually is a minor consideration but can be significant in low-lift pumping applications that are why velocity head should always be included in the calculation. Normally kinetic energy (or velocity head) is lost when flows are discharged into a larger pipe or into a reservoir. The kinetic energy can be recovered with gradual velocity reduction. If the velocity head is a significant factor (more than say 5 percent of TDH) which may be the case in low lift applications, particular attention should be given to hydraulic computations and all minor losses should be computed. TDH is the steady state head that will need to be developed by pumping equipment under operating conditions. TDH does not include temporary surges or increased head conditions (due to starting and stopping and associated valve operation) that may prevail for less than 30 seconds. In the US, TDH is normally quoted in feet of water of head. For SI units, the correct term for head (pressure) is kilo Pascal (kPa) but in practice it is often quoted in meters. (1 meter of head is equivalent to ten kPa) One reason that head is quoted in linear units (feet or meter) instead of pressure units is that head produced by a pump may be quoted linear units without correction for specific gravity. Thus, head is interchangeable for pump performance at different specific gravities. Whenever there is an application using sea water (or liquids other than fresh water), the head developed by the pump must be multiplied by specific gravity in order to compute pressure and energy requirements. 2.4.1.3.
System Head Curves In order to establish typical pump operating conditions, it is advisable to graphically represent the total range of pumping conditions with system head curves. Once such curves are prepared, they can be overlaid with pump performance curves. See Section 5.1 for methodology for creating a system curve.
2.4.1.4.
Major Pump Stations For major pump stations (in excess of 10,000 HP connected loads) factors which may influence the number or units include:
Limitations of size for commercially available pumps. Large pumps and motor are available up to 30,000 horsepower
Impact on power grid of starting large motors based on motor starting current
Matching power demands with generation capacity and other pumping stations.
A review of major large pump stations with capacities to 5,000 cfs for the US Bureau of Reclamation, California Aqueduct Pump Stations by State Water Resources Board, Central Arizona Water Project, Southern Nevada Water Authority and MWD of Southern California, indicates that the number of pumps ranges from 2 to nine units.
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OCT 2011 2.4.1.5.
Medium Size Pump Stations For medium size plans, say 500 to 10000 HP there may not be size limitations on commercially available equipment but starting electrical loads may influence the maximum motor size. Other factors which may influence the number of units include:
Starting and stopping frequency due to forebay size or delivery side storage limitations
Client’s standards, or requirements for more than one standby unit
Provisions for future expansion
Delivery to more than one water system pressure zone
The unit costs of design and construction are increased when more than one-size (of pumping unit) is specified. Not only are pump layouts and specifications affected by more than one size of pumps but mechanical appurtenances (including valves and pipe fittings) and electrical (motors, starters ad controls) details are also more complicated. The client’s requirements for stocking spare parts and other operating considerations, such as maintenance manuals, servicing and records, may be increased. In the long run, the perceived advantage of providing smaller pumps “for in-between flows,” may be lost. Unless there are specific limitations on electrical loads or frequency of stopping and starting (due to inlet or discharge considerations) the “one size” layout is preferable. 2.4.1.6.
Small Pump Stations Pumping stations with total installed capacity of less than 500 HP are the most numerous applications for water and sewage. For sewage pumping plants, there is a need to be more conservative than for most water applications. It is common practice to provide two standby pumps for sewage pumps and it also may be the clients’ preference to provide two sizes of units (one size for normal dry weather flows and one size for peak wet weather flows). Thus, the minimum number of units for sewage plants may be three (or four if the client so directs) For water applications, it is necessary to consider if the facility that is being proposed is the sole source of water for the area being served or if there are other pumping or gravity sources available. If the facility is the sole source of water and it serves an area with limited storage (less than 6 hours) or high fire risk (industrial and/or heavy commercial) then two standby units could be provided. For stations servicing residential areas and areas with adequate storage (capable of furnishing peak hour demands, fire flow and emergency provisions) a simple 2-unit stations (one duty and one standby unit) may be applicable.
2.4.1.7.
Standby Units and Standby Power Supply The number of standby pumping units is usually based from the Clients preference or as mandated by the EPA or other applicable government agency to meet the reliability design criteria. Standby unit is defined as the additional pump unit(s) in addition to the minimum number of unit required to deliver the maximum pump station capacity with one largest unit out of service. The capacity of the standby pump shall be equal to the largest pump unit. Several factors enter into an analysis of the risk of power interruption (vulnerability) associated with the pumping design. The risk factors that need to be evaluated include: equipment reliability, electrical demand patterns, power interruption frequency and available forebay storage or emergency storage. It is seldom possible to compute and accurate or comparable risk factor. Historical data is generally not representative of future interruptions because the causes of past interruptions may have been partially corrected. Also future conditions may not have been experienced in the past. Unless it is a contract requirement, risk analysis should be avoided and the rationale for standby units (and power supplies) should be evaluated based on the following considerations.
In the case of water systems, most short-durations power interruptions are not a serious concern because of the provision of system storage. Most water pumping stations therefore, do not include standby power provisions but do include an electrically-driven standby pumping unit with Page | Chapter 2-33
OCT 2011 a capacity equivalent to the largest unit. Generally, the standby unit is identical and interchangeable with other units and there are provisions in the control system for any pump to be designated as the ‘lead pump” and any unit to be designated the standby unit.
2.4.1.8.
Power interruption is more of a concern with sewage pumping plants because of accidental sewage overflow to the nearby river or ocean. Also the risks associated with maintenance on pumps are significantly higher with sewage pumps, as compared to water pumps. If the client has adopted policies with respect to standby units and/or standby power, they should be accepted, unless it is apparent that they are not adequate. In general, two standby pumps should be considered for sewage pumping stations.
Net Positive Suction Head (NPSH) The NPSH available (NPSHa) in the system is the total suction head in feet of liquid being pumped (absolute measured at the pump centerline or impeller eye) less the absolute vapor pressure (in feet) of liquid being pumped. Please refer to the Cameron Hydraulic Book or the Hydraulic Institute Standards. NPSHa = (144/w)(Pa-Pvp) + hs Where; Pa = atmospheric pressure, psia Pvp = vapor pressure of liquid in psia W = specific weight of liquid in pounds per cubic foot The NPSH required (NPSHr) by the pump is usually indicated on the pump data sheet or pump curve and it is referred to at the pumps’ best efficiency point. The information must be obtained from the pump manufacturer. NPSH characteristics are particular to each pump. It is important for pump station design engineers to understand the relationship between the impeller design versus, head, capacity, speed and suction condition which determine the shape of the pump curve. Refer to the Hydraulic Institute Standards for additional information regarding the relationship between NPSHr and Suction Specific Speed “S”. S=rpm(gpm)0.5/(NPSHr)0.75 Where: S = specific speed rpm = speed NPSHr = feet absolute The recommended suction specific speed value should be limited to 8,500. Higher or lower values maybe used depending on liquid properties, intake design, impeller suction capability, materials of construction and application experience. If higher specific speed is to be used, consult the pump manufacturer. The data from one pump model or impeller type cannot be extrapolated to a larger mode or to a high speed application. The only safe assumptions that can be made are:
NPSH margin shall not be less than 5 feet ( NPSHa=/>NPSHr +5 ft)
If higher specific speed is to be used, consult the pump manufacturer
Figure 2-25 is typical of information on NPSH that may be made available by pump manufacturers. NPSH requirement are often shown on the lower right hands side of pump performance curves and generally have a separate vertical head scale as shown.
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OCT 2011
Figure 2-25 Typical Manufacturer’s Performance Curve Showing Required NPSH
The following facts should be noted regarding NPSH:
Required NPSH is always inversely related to pumping head but is not otherwise related.
The NPSH data is generally only shown for performance on the right side of the performance curve. It may be assumed that requirements on the left of the curve will not be critical.
Required NPSH is normally applicable to all impeller trims shown on pump performance curves.
The NPSH data is applicable only at the speed shown. Small increases in speed (i.e. from indication speeds to synchronous speeds) may cause significant changes in requirements.
The data is not transferable from one pump manufacturer (or one pump model) to another, even though other performance characteristics appear almost identical.
In practice, not less than three NPSH curves from different manufacturers should be obtained for each pump size application. If all curves indicate that the required NPSH, under maximum flow conditions is less than 30 ft than normal submergence requirements will be applicable (except for warm or volatile fluids). At elevations above 1,000 feet above sea level adjust barometric pressure for elevation change when calculating for NPSHa. The higher the site elevation, the higher the required submergence. If during design for a certain application, it is determined that NPSH may be a problem, it may be necessary to consider the following alternatives
The greatest risk of cavitation occurs when a pump operates at lower than anticipated discharge pressures and the operating point moves to the far right of the performance curve. Design criteria should always be reviewed to determine if the original selected design head is too high. In practice many cavitation problems are due to over-estimation of the head requirement and consequent operation to the right of the performance curve, in the zone of high required NPSH.
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OCT 2011
NPSH requirements are influenced significantly by pump speed. If required NPSH adversely influences design, it may be necessary to consider lower speed pumps.
An obvious solution would appear to be to increase adequate available NPSH at the suction of the pump by increasing submergence of the pump impeller and/or reducing friction and/or velocity head losses on the suction side of the pump. Such solutions however may not be feasible.
In some instances, it may be possible to minimize cavitation problems in existing installation by changing impellers or changing metallurgy of impellers and/or pump suction components but such potential solutions should never be relied upon during the design stage or consult the pump manufacturer.
2.4.2.
Material Considerations Welded steel is typically used for pump station piping. However, certain clients and regional practice may dictate the use of ductile iron or PVC pipe and fittings. In such instances, the primary concern is the cost and space requirements for flanges. Welded steel pipe is normally devoid of flanges, except where connections to flanged valves and other flanged equipment are required. However, it is sometimes convenient to provide a flanged elbow to facilitate removal of a valve and avoid the use of a mechanical couplings or dismantling joints. (i.e. Victaulic) Steel pipe and fittings have many advantages over ductile iron and/or PVC for pump station applications because it can be fabricated to suit. It is normally structurally superior and can be fabricated to conform to most configurations. Steel pipe is almost always prefabricated in a shop, using shop drawings prepared by the manufacturer and reviewed by the design engineer. Included with the prefabricated pieces and fittings are makeup pieces, usually in the form of butt straps, to facilitate mating up continuously welded pipe. Elbows, tees, wyes and specialty fittings are fabricated from previously rolled and testing straight pipe. Outlets on the suction and discharge header are reinforced to comply with design standards shown in AWWA Steel Pipe Manual M-11. Flanges are usually furnished loose for field welding. Steel pipe and fittings are generally furnished with cement mortar lining and mortar coating for buried installations, and mortar lining with no coating for exposed use. On-site buried pipe should be consistent with adjacent pipelines and coating systems and corrosion protection should be coordinated with adjacent pipeline design and practice. To aid the design engineer, MWH has developed a Piping Schedule based on experience and industry standards. The Pipe Schedule correlates the process and the typical pipe and valve materials used for a specific process. The design engineer should always callout the pipe size, fluid and pipe material using the MWH Standard Tagging system as indicated in the Piping Schedule. The Piping Schedule is included in Appendix B and is available on Delivery Framework. The station piping is usually lined with material compatible with the fluid handles and to protect the pipe from corrosion or erosion. The design engineer has a variety of options available with regards to pipe lining. The lining should be selected based on the process and specific properties of the fluid. Ideally the lining should protect the interior of the pipe and extend its useful life. The lining material and its thickness are based on the characteristics of the liquid being pumped; there-fore, the design engineer needs to confirm what liquid(s) are transported through the piping system prior to making this selection. The following pipe lining materials are commonly available:
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OCT 2011
Table 2-4: Commonly Used Pipeline Materials Lining Material
2.4.3.
Service
Mortar Lined
General raw water, treated water; reclaimed water; raw sewage, wastewater
Epoxy
General raw water, treated water; reclaimed water; raw sewage, wastewater
Glass Lined
raw/primary sludge; scum; thickened sludge; digested sludge dewatered sludge;
Polyurethane
Raw sewage up to aeration basins; any piping systems that are intermittently wet and dry
System Boundary for the Piping Layout Design work is typically divided based on specific disciplines. Some of the disciplines have clear dividing lines with regards to the extent of the work, while others are less clear. Mechanical and civil tend to overlap in responsibility when it comes to buried piping. The interface point between mechanical should be clearly decided before the start of the design. Typically, the interface between mechanical and civil occurs at approximately 3 ft beyond the exterior of the building wall at a buried pipe coupling. Where differential settlement between the building and the yard piping due to type of soil condition, the piping system shall be provided with two sleeve couplings spaced at least 5 to 10 feet between centers to allow the pipe to articulate and adjust for differential settlement. Where the differential settlement exceeds the capability of the sleeve coupling, ball type coupling by EBAA shall be used. The amount of differential settlement shall be recommended by the Geotechnical Engineer.
2.4.4.
Sizing the Suction and Discharge Piping In development of the piping layout, the design engineer shall determine the size of the suction and discharge piping. For purposes of this discussion, suction and discharge piping refers to the piping immediately upstream and downstream of the pump. The terms suction and discharge header refer to manifolded piping where flow streams from multiple pumps are combined. The suction and discharge pipe sizes for each pump are usually dictated by the flow stream velocity within the pipe when only one pump is operating. The flow where the system head curve intersects with the pump performance curve is usually the worst case flow scenario. The suction and discharge header shall be determined using the pump station firm capacity. Firm capacity is the maximum capacity of the pumps station with the largest pump out of service. The design engineer shall also evaluate the full range of flows including minimum flows and future flows. Based on the process, a minimum flow rate may be required to keep solids suspended in the flow stream. Furthermore, higher flows in the future may be the controlling factor when sizing the suction and discharge pipe sizes.
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OCT 2011
Figure 2-26: Typical Suction and Discharge Piping 2.4.4.1.
Suction Piping Suction Pipe Size In order to optimize the suction piping, the design engineer shall select a size which results in a maximum flow velocity between 2 and 5 feet per second (fps) at maximum pump flow rate. Typically suction side velocity is low to minimize the impact on the NPSHa. High velocities induce suction side losses which reduce the overall NPSHa. Furthermore, high velocities on the suction side could result in non-uniform velocity distributions entering the pump impeller, creating impeller imbalance and vibration issues. Table 2-5: Recommended Suction Side Velocities Special Applications
Recommended Minimum Suction Side Velocity
Solids Handling
>2.5 ft/sec
Slurries
>5 ft/sec
Mining Slurries
Representative sample should be sent to a testing facility to determine the carrying velocity, settlement velocity, shear, specific gravity, corrosivity, and friction factor
Suction Pipe Length Suction piping must have a straight approach length leading into the pump greater than 5 times the pipe diameter. Straightening vanes may be provided to reduce the approach length, however, the design engineer must consult with the Chief Mechanical Engineer before using straightening vanes in a project.
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OCT 2011
Figure 2-27: Suction Piping Configuration Excerpt from Hydraulic Institute Intake Design Standard Suction Pipe Fittings Provide suction piping with eccentric reducers adjacent to the pump. The reducers shall be mounted with the straight section on top, to preclude the trapping of air inside the pipe. (If an eccentric reducer cannot be provided, DO NOT provide an automatic air vacuum release valve because the air valve can leak and admit air into the suction piping – rather, provide a manually operated ball valve for venting air during initial startup.) Eccentric reducers may be mounted directly on the suction flange of the pump. Suction Valves The design engineer shall also review the design, for any features which would create an uneven flow distribution in the pump. For example, horizontal split-case double-suction centrifugal pumps include a horizontal suction nozzle baffle. If the pump experiences an uneven flow with the same orientation as the suction baffle, one side of the baffle receives more flow than the other. This uneven flow distribution is detrimental to the pump performance. The source of an uneven flow could be a butterfly valve on the suction piping. As flow passes through a partially open butterfly valve, it is directed towards one side of the downstream pipe creating an unbalanced flow distribution. If the unbalanced flow distribution is aligned with the suction baffle, more flow enters one side of the baffle as opposed to the other side. As a result, the unbalanced flow distribution enters the eye of the impeller. To maintain an even flow distribution into the pump, the suction isolation butterfly valve should be installed with the shaft in the vertical position perpendicular to the pump suction nozzle baffle. The uneven flow distribution is guided downward allowing an equal amount of flow to enter each baffle area.
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OCT 2011
Figure 2-28: Vertical Turbine Intake Flange Excerpt from Floway Pumps Turbine Pump Handbook Vertical Turbine Pump Barrel/Can Installation Vertical turbine pumps in a “barrel or can” installation, the suction piping are connected to the barrel. Flow enters the barrel, and is guided downward entering the suction bell of the bowl assembly. Where the suction inlet is connected above the suction bell, the barrel inside diameter should be sized for a velocity in the annular space between the ID of the barrel and the OD of the pump bell, bowl or flanged column, (whichever is greater) does not to exceed 3 ft/sec, based on the maximum flow of the pump. For small and medium sized pumps (200 to 2000 gpm) barrel velocities to 5 ft/sec may be applicable. For large applications, refer to pump manufacturer. Mixed flow and propeller pumps should not be barrel mounted due to the high capacities confined to the barrel. The Hydraulic Institute Guidelines for Intake Design Standards identifies specific dimensional criteria for the suction piping associated with vertical turbine barrel/can installations. This criteria describes the suction pipe approach length and the inlet location relative to the pump suction bell. With regards to the approach length, the horizontal suction piping must have straight approach length (i.e., no flow disturbances such as valves) greater than 5 times the suction pipe diameter. As stated previously, the intent of the approach length is to establish a uniform velocity distribution at the inlet to the barrel. The second dimensional criteria indentified in HIS are the distance between the barrel/can inlet and the pump suction bell. MWH exception to HI, the vertical distance between the centerline of the suction piping and the pump suction bell must be a minimum of 3 to 4 times the pump "can" inside diameter instead of 2D. Refer to the Hydraulic Institute Standards for additional requirements, however HIS requires only twice the can diameter based on MWH experience, additional distance is required in order to allow the flow to straighten before it reaches the suction bell. The pump “can” or “barrel” must be furnished with air/ vacuum valve in accordance with MWH Standard Detail M-119.
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OCT 2011 2.4.4.2.
Discharge Piping The velocity limitations at the suction piping are primarily due to the inlet conditions of the pump. On the discharge side, however, the flow velocities can be higher. The discharge pipe diameter is dictated by balancing the most economical pipe size with the effects of high velocity flow. At a specific flow rate, as the pipe diameter is reduced, the flow velocity increases thereby increasing the head loss through the pipe. It is normally economical to design on-site discharge piping for higher velocities because of the higher average unit costs of the more complex piping and more numerous valves and fittings appurtenant to pumping stations. Velocities leaving pumping units are frequently in the range of 10 ft/sec and it is practical and economical to pass such flows through valves and manifolds before the velocity head is dissipated. The off-site piping is often designed with velocities between 6 and 10 ft/sec. For water conveyance piping longer than one mile, a pump-pipeline economic analysis study shall be performed to determine present worth versus pipe size. A copy of an example pump-pipeline economic analysis study is shown in Figure 2-29.
Pumped Pipeline System Economic Analysis 10
$50,000,000 $45,000,000
9
$40,000,000 8 $35,000,000
Annual Cost ($)
6
$25,000,000 $20,000,000
5
$15,000,000 4 $10,000,000 3
$5,000,000
Water Velocity
7
$30,000,000
2
$60
62
64
66
68
70
72
74
76
78
80
82
Pipe Diameter Total Annual Cost
Annual Pumping Cost
Annual Pipe Cost
Water Velocity
Figure 2-29: Example Economic Analysis of Pump and Pipeline system The following table is a guide for velocities to be utilized for water and wastewater pumping plants. Detailed hydraulic investigations and consultation with equipment manufacturers may result in adjustment to the listed velocities. Reducing the velocities indicated is safe but may result in a less economical design. Increasing the velocities by more than 10 percent, however, should not be undertaken without careful investigation and approval from the Chief Mechanical Engineer.
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OCT 2011
Table 2-6: Summary of Recommended Maximum Pipe Velocities Piping Segment Description
Ft/sec
m/sec
On-site suction delivery pipe
5.0
1.52
Suction pipe to individual pump units or pump barrels
5.0
1.52
Nominal velocity through suction valve (90% minimum port area)
5.0
1.52
Maximum actual downward velocity in the vertical pump barrel.
3.0
0.91
Net velocity in vertical pump discharge column after reduction of column shaft or inclosing tube
10.0
3.05
Discharge pipe from each pump Nominal velocity through discharge
8.0
2.44
Valves (90% minimum port area)
8.0
2.44
Discharge manifold
10.0
3.05
Fire Pump Manifold
12.0
3.66
Bypass or return flow piping
20.0
6.09
Maximum nominal flow through a butterfly valve
16.0
4.88
* Based on nominal capacity of pumping facilities or the design capacity of individual units as Applicable.
Figure 2-30: Example Photograph of Discharge Piping 2.4.4.3.
Pumps without Suction Piping Submersible non-clog centrifugal pumps and vertical turbine pumps which are directly taking suction from the wet well do not require suction piping. Wet well suction configuration shall be designed in accordance with the Hydraulic Institute Standards.
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OCT 2011
2.4.5.
Pressure Rating of the Piping and Valves The maximum allowable design pressure of the pipe flanges or valve shall be based on the design head or shut-off head of the pump whichever is larger. The maximum transient pressure is kept less than 125 percent of the pipe design pressure by providing proper surge protection devices. The piping system, valves and flanges are tested 125 percent of the maximum allowable pressure rating to allow for transient pressure rating. This information is used to determine the pipe wall thickness and the class of flanges used on the equipment and fittings. To mate flanges of different standards and ratings requires that both flanges have pressure ratings equal or above the maximum anticipated line pressure Table 2-7: Summary of Flange Pressure Ratings and Fit Up AWWA Flanges
Mate to ANSI Flanges
Class B (86 psi, steel) Nominal sizes from 6” - 96”
Class 125 lb Std., Cast Iron
Class B (86 psi, steel) Nominal sizes from 6” - 96”
Class 25 lb. Std., Cast Iron
Class B (86 psi, steel) Nominal sizes from 6” - 24”
Class 150 lb. Std., Steel
Class D (175 & 150 psi, steel) Nominal pipe sizes 6” - 96”)
Class 125 lb. Std., Cast Iron 6” – 12” inclusive 175 psi; larger sizes 150 psi Class 150 lb. Std., Steel 6” – 12” inclusive 175 psi; larger sizes 150 psi Class 125 lb. Std., Cast Iron 6” – 12” inclusive 175 psi; larger sizes 150 psi Class 150 lb. Std., Steel
Class D (175 & 150 psi, steel) Nominal pipe sizes 6” - 24”) Class E (275 & 150 psi, steel) Nominal pipe sizes 1” - 96”) Class E (275 & 150 psi, steel) Nominal pipe sizes 1/2” - 24”)
The design engineer must identify the maximum system pressure during normal and abnormal operation for a specific section of pipe. A good starting point for determining the maximum pressure rating of the piping is to determine the shutoff head for the pumps. The shutoff head is the maximum pressure created by the pump at zero flow. Shut off head is a differential pressure; therefore the suction pressure should be added to the shutoff head in order to determine the total discharge pressure of the pump. This discharge pressure represents the highest pressure generated by the pump. In some cases, it may be necessary to increase the pressure rating of the suction piping. Pump systems are typically equipped with check valves on the discharge side of the pump. In the event check valve fails, the valve allows the system pressure to migrate through the pump to the suction piping. The suction isolation valve, flanges, piping, sleeve (or Victaulic-style) coupling, and suction nozzle must be rated at the pressure rating of the discharge piping. Harness or restrained joints must be designed for a maximum pressure equal to the discharge piping. The design engineer must also account for transient conditions. In the event of a hydraulic surge, the pressures in the piping can dramatically increase. Hydraulic Transients are discussed in further detail in Section 2.9. The design engineer should consult the Senior Hydraulic Specialist to determine a realistic maximum pressure for the piping.
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OCT 2011
2.4.6.
Flexible Couplings and Dismantling Joints When designing the piping layout, the engineer, shall include features considered good practice when it comes to maintenance and operations. The piping system shall be designed for flexibility and ease of disassembly. It is typically good practice to include dismantling joints upstream and downstream of a pump to facilitate removal of the pump. Dismantling joints are flanged adaptors or sleeve couplings or grooved mechanical joints. This flexible connection or expansion joints such as rubber or stainless steel bellows shall be allowed only for high temperature applications such as in the hot water or digester sludge pumping application. The use of flexible bellows connection at the suction and discharge have been misapplied in many situation because the contractor relies on the flexibility of the joints to make up for the misalignment between the pump and the piping system instead of aligning the piping to the pipe in the first place. The end result was the bellows was forced to connect to the pump, causing the pump to misalign. The pump suction and discharge nozzles are not designed to support the piping system loads. Significant loads on the suction and discharge piping may distort the pump casing (or discharge head) applying unnecessary stresses to the casing. In some cases, exceeding the allowable nozzle load has been associated with excess vibration. The design engineer should also consider the maintenance aspects of the design. Pump and valves need to be removed for periodic maintenance. During removal of a valve, the operators pull the piping apart axially to separate the flanges. To assist in this process, the piping should be designed with dismantling joints. A dismantling joint is a type of pipe coupling specially designed with a small gap. The operators are able to collapse the dismantling joint creating a gap which can be used to move the piping axially. The design engineer should be familiar with the various types of dismantling joints and pipe couplings. The design intent may suggest one coupling over another. The following is a list of typical coupling types.
Flexible Coupling
Dismantling Joint
Sleeve Coupling
Victaulic Coupling
Figure 2-31: Examples of Various Pipe Coupling Fittings
2.4.7.
Bridge Cranes Limitations to Piping Layout When utilizing a bridge crane, the design engineer shall verify the full range of motion for the lifting hook, in both the vertical and horizontal planes. The range of motion (and lifting capability) of bridge crane is limited by the physical constraints of the trolley and hoist. The design engineer shall verify that equipment and valves are located within the lifting range of the bridge crane. This verification is critical to finalizing the overall building dimensions. Any errors in determining the range and lifting capability may lead to costly rework of the structural design.
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OCT 2011
Vertical Range The design engineer shall verify each piece of equipment can be lifted and moved to various locations in the pump station. The lifted components must be able to clear the height of railing and adjacent equipment and piping. The most common mistake in determining the high hook elevation, is not accounting for the lifting straps or chains. The bridge crane hook is never connected directly to the equipment. Typically lifting strap or spreader bar is used. The design engineer shall determine how the equipment shall be lifted (straps or spreader bar) and include these dimensions in determining the high hook elevation. Special spreader bar can be specified for large vertical motor and vertical turbine pump removal. The design engineer must pay special attention when dealing with vertical turbine pumps. Due to the overall length of the pump, it may not be possible to remove the pump as one unit. In an enclosed building, it may be necessary to disassemble the pump as it is being removed from the wet well. Initially, the discharge head and motor are disassembled and removed. Next, the remaining column and bowl assembly is lifted out of the water until he next joint is visible. The intermediate column pieces may be as long as 20 feet unless otherwise stated in the project specifications. The bridge crane high hook elevation must be high enough to allow this range of lifting. OSHA requires minimum clearance of 3 inch from the top of the trolley assembly or any component of the crane and the bottom of the roof support structure and 2 inch on the sides. Provide a minimum clearance of 18 inches on the top and 12 inches on the sides to allow for any variation of dimensions between specified manufacturers. Horizontal Range The design engineer must also verify the horizontal lifting range. When the bridge crane is installed, the hoist and trolley have a limited range of motion. The design engineer shall review the bridge crane manufacturer’s drawings to determine the full range of horizontal motion for the bridge crane hook. The design engineer shall include this lifting zone on the pump station plan drawings as a separate layer than can be turned on and off.
Figure 2-32: Typical Bridge Crane
2.4.8.
Pipe Differential Settlement Where differential settlement of buried piping is anticipated and cannot be prevented, means must be provided to prevent damage to the pump and/or stresses on the pump or appurtenant fittings. This can be accomplished in two ways: 1. By providing at least two flexible couplings at a minimum spacing of 10 ft. The couplings nearest the point of maximum shear) adjacent to the wall of a structure) should be located no more than two feet from that point. Coupling manufacturer’s data indicate the maximum allowable deflection
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OCT 2011 per coupling and assed upon the estimated differential settlement (if available) the minimum spacing of coupling can be estimated. 2. By providing articulated piping at the interface where settlement is expected to be the greatest. This is usually accomplished with two offset 90 degree elbows and mechanical-type ductile iron fittings to allow for rotation of the elbows. Groove joints are not allowed for buried application because they are prone to leakage. 3. By providing ball type joints where differential settlement is in excess of what the sleeve coupling or mechanical type DIP fittings can absorb. Whether for installation and removal of appurtenances, for differential settlement or for ease of joining two pieces of pipe, couplings should be kept to a minimum practicable number. They should be placed where needed but should not be placed indiscriminately, as they can be a source of leaks. Couplings most commonly used in pumping station piping are mechanical or grooved-type (Victaulic) and sleeve-type (Dresser or Baker). The mechanical-type can move axially only a fraction of an inch while sleeve-type units are designed to allow for considerably more movement. A harness set on such couplings may be necessary if additional forces can be developed.
2.4.9.
Thrust Restraint and Pipe Anchorage All pressure pipes should be axially restrained in order to contain hydraulic thrust internally within the pipe. Piping connections such as welded, flange, sleeve coupling with harness bolts, groove type coupling such as Victaulic couplings and DIP mechanical joints with thrust restraints are among the few method of providing thrust restraint. Residual thrust external to the elbows and bends can either be supported using thrust blocks or thrust supports with forces transferred to the ground. The pump should not be used as an anchor for piping. Pumps should be isolated for the piping system using expansion joints for high temperature applications. Site piping must be adequately anchored and isolated in a manner that prevents forces being transmitted to the pump and appurtenant fittings. Anchorage of such piping by concrete thrust blocks or wall flanges is normal practice. A flexible coupling between such anchor and the pump may be necessary to ensure that pipe forces can be relieved and to ensure that the pump and adjacent valves can be removed. Continuously joined and buried pipe may be self-anchored if the length of pipe and type of soils are suitable. The required length of joined pipe necessary to provide anchorage is proportional to the maximum operating pressure. Other design factors include: diameter, soil types, coating type, depth of cover. The length of pipe required for anchorage should be determined based on soils report data and reviewed by an expert in anchorage. Refer to AWWA M-11 for design guideline. High temperature piping shall be designed by calculating the thermal expansion of the pipe per unit length. The piping system shall be supported using pipe anchors, fixed and sliding supports strategically located along the piping alignment to direct the expansion away from the pipe anchor and contained within the expansion joints. Expansion loops is another alternate means of absorbing thermal expansion of piping. For more information, refer to Crane Piping handbook for pipe supports. Pump supports shall be per pump manufacturer recommendation. It is recommended that the pump be relieved with any external thrust associated with the piping system. Consult the pump manufacturer as to the maximum allowable nozzle load to be imparted by the piping system.
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OCT 2011
2.5.
Preliminary Valve Selection Once the piping layout concept is defined, the design engineer shall select the appropriate valves for the system. The type of valves used at the pump station is of significant importance as they must not only be applicable to the process, but work with the pump station control scheme. Typical valves used in pump stations are isolation, check, pump control, air and vacuum valves. Depending on the system operational requirement more specialized valves can be utilized including pressure reducing, pressure relief, pressure sustaining, energy dissipation and other specialty valves. The following sections briefly discuss the various types of valves.
2.5.1.
Isolation Valve Considerations Isolation valves are typically located both upstream and downstream of the pump in fully open or fully closed valve positions. If a pump is to be taken off line, the upstream and downstream valves are closed. Otherwise the valves are fully open. The most common type of isolation valve is the butterfly valve. Butterfly valves are preferred for water applications, while raw sewage and storm water applications require full port gate valves, eccentric plug valves, bonneted knife gates or other appropriate valves. The reason for the distinction is butterfly valves do not have a full-port opening and it is not suitable for fluids with stringy materials. The disc (sealing element) rotates about the centerline of the valve in the center of the flow stream. Therefore, the disc has the potential to catch stringy material and debris commonly found in raw sewage and storm water. Butterfly valves are also preferred for isolation applications in large water transmission and distribution pipelines operating at less than 150 psi. High pressure butterfly valves rated from 250 to 400 psi are available in triple offset configuration. In buried pipelines, valves 24-inch and larger should be installed in a vault for ease of repair and/or removal. When dealing with flow meters, full port valves are required to minimize flow disturbance through the meters, affecting its accuracy. At a minimum, a single isolation valve should normally be in-stalled on the discharge header, downstream of the flow meter, to allow removal of the meter without dewatering the entire pipeline.
2.5.2.
Check Valve Considerations Check valves shall be installed at each pump discharge to prevent the flow from draining back through the pump. There are a number of different types of check valves available to prevent flow reversal, such as globe type silent check, slanting disc, and swing check with air or hydraulic cushion-type. For small and medium sized potable water applications, slanted disc check valves are most common. For sewage applications, swing check valves with external weight or springs are applicable. MWH does not recommend the use of double door check valves because they have been found to fail during surge conditions. These valves typically do not have any type of the external visual confirmation that the valve is open. As a result, not only is it impossible to tell what position the valve is in, but if there was a valve failure, there would be no way to know. Furthermore, the quick closing response of these valves has been known to create slamming issues. During a surge event, the slamming may be great enough to break the valve.
2.5.3.
Control Valve Considerations Automatically controlled valves are typically used in lieu of the conventional check valve when the surge analysis requires controlled opening and closing in order to alleviate surge pressures. It functions like a check valve but it offers an adjustable opening and closing periods. These are known as pump control valves. They are designed to be fully closed when the pump starts and, through an operator, slowly open over a pre-determined time period. When the pump is required to stop, the controller calls for the valve to slowly close before the pump actually stops. Control valves shall be capable of closing automatically after a power failure event using stored energy such as an air or nitrogen accumulator. Thus, through the control valves, the system transitions from no flow to full Page | Chapter 2-47
OCT 2011 flow and back. Pump control valves may be actuated by diaphragm, pneumatic or hydraulic piston operators. Valves used for pump control should have good throttling characteristics, such as globe, plug, and cone or ball configurations. Typically valves on discharge piping are designed for a velocity of approximately 8 ft/sec. When required, globe pattern valves, globe pattern valves may be utilized as combined pump control and check valves. Under such applications, normal velocities through such valves should be less than 12 ft/sec.
Figure 2-33: Example Control Valve Installation 2.5.3.1.
Butterfly Valve The butterfly valve is a quarter turn rotary valve that controls flow and pressure by rotating a circular disc supported on a shaft to a circular seat. The AWWA C504 valve is equipped with a rubber seat. For pressures higher than 250 psi and beyond the rating of AWWA butterfly valves, triple offset butterfly valves are recommended. The rubber seat is not conducive to high velocities and sustained throttling and may fail in a low angled throttled position (<20º). Similar to the ball and cone valve, if a butterfly valve is being used for flow and pressure control the seat should be metal to metal to mitigate damage from high velocities occurring during the throttling process. The butterfly valve has a limited throttling range of 20º or higher. When throttled at lower angles the velocity through the butterfly valve becomes high on two sides of the disc and may induce vibration due to high unbalanced dynamic torque on the disc. Valve cavitation may also occur at a low angled throttled position. Below is a list of the valve characteristics of the butterfly valve.
Lightweight, compact, and relatively inexpensive
Moderate head-loss across the valve when in a fully open position and properly sized
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OCT 2011
Susceptible to cavitation in a throttled position and if severe cavitation persist the valve is subject to damage
Limited pressure control characteristics in low flow high pressure drop conditions
Susceptible to cavitation and choking in low back pressure conditions
Figure 2-34: Example Butterfly Valve Details 2.5.3.2.
Cone Valve The cone valve is representatively named. The valve controls flow and pressure by seating a cone into a conical shaped valve body through a rotary (90º) movement. Because cone valves are commonly used for throttling, the seat is typically metal to metal to mitigate damage from high velocities occurring during the throttling process. The cone valve is capable of precise throttling under high head and high flow velocity conditions. Below is a list of the valve characteristics of the cone valve.
Low head-loss across the valve when the valve is in a full open position and properly sized
Good throttling characteristics in low flow conditions
With metal seating the valve is suitable for continuous throttling
Has large dimensions requiring adequate space in a vault or dry pit
The actuator associated with the valve is tall
Figure 2-35: Example Cone Valve Details
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OCT 2011 2.5.3.3.
Ball Valve The ball valve is a rotary (90º) valve which controls flow and pressure by rotating a spherical shape with a hollow cylindrical core. Ball valves are typically equipped with either a metal to metal seat or a rubber to metal seat. Resilient seated ball valves are normally used for bubble tight application. When ball valves are being used for flow and pressure control the seat should be either reliant seated or metal seated. When being used as a throttling valve, the ball valve actuator can be made to provide a direct 1:1 ratio to open and closing position allowing for precise control of the valve. Below is a list of the valve characteristics of the ball valve.
Low head-loss across the valve is in a full open and properly sized
Good pressure control characteristics in low flow conditions
Durable valve suitable for continuous throttling
The actuator associated with the valve is tall
Susceptible to cavitation and choking in low back pressure conditions
The metal seated ball valve may experience a small amount of leakage even when fully closed
Figure 2-36: Example Ball Valve Details 2.5.3.4.
In-Line Sleeve Valve The in-line sleeve valve has a linear axial action that controls flow and pressure by advancing or retracting a valve gate along a fixed perforated sleeve with a hollow cylindrical core. Sleeve valves are typically equipped with a metal to metal seat consisting of the sleeve and gate. The sleeve valve is specifically engineered to provide a range of flow and pressure control and is ideally suited for low flow and high pressure reduction applications. The valve design is engineered to minimize damage to valve components during cavitation by directing the cavitation to the center of the fixed sleeve and away from metal components. The sleeve valve actuator can be made to provide a direct 1:1 ratio for opening and closing position or made to follow a proportional curve. Below is a list of the valve characteristics of the Henry Pratt sleeve valve.
Excellent pressure control characteristics in low flow conditions
Usually less prone to cavitation as compared to other types of valves
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OCT 2011
Durable valve suitable for continuous throttling
High head-loss across the valve
Has large dimensions requiring adequate space in a vault
Relatively expensive
Figure 2-37: Example Sleeve Valve Details
2.5.4.
Specialty Valve Considerations
2.5.4.1.
Pressure Relief Valves Pressure relief valves are provided when it is necessary to protect the system against excessively high pressures. Protection is provided by relieving the high pressure to the suction side of a pump station or to atmospheric pressure in the wet well. These types of valves are not typically provided adjacent to the pump because of the other safety features normally provided, such as pump control valves and pressure switches. Pressure relief valves are usually of the globe pattern or diaphragmtype. With regards to design criteria, the flow velocities should not exceed 20 ft/sec based on the nominal diameter. MWH does not recommend the use pressure relief valve in lieu of surge tank for surge protection. Relief valves do not activate fast enough to relieve surge pressure in the pipeline.
Figure 2-38: Pressure Relief Valve
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OCT 2011 2.5.4.2.
Pressure Sustaining Valves Pressure sustaining valves are utilized where it is necessary to maintain a minimum pressure in the system upstream of the valve. They are seldom used at pumping stations because it burns energy but may be provided in distribution systems. They are usually of a similar design as valves used for pressure reduction.
Figure 2-39: Pressure Sustaining Valve 2.5.4.3.
Pressure Reducing Valves Pressure reducing valves are frequently installed within the distribution system to reduce pressure and maintain constant pressure downstream into a sub-system. They are rarely located at the pumping station unless the sub-system is so small the cost of providing separate pumps is unwarranted. Pressure reducing valves may be of several types. However, globe-pattern, diaphragm or piston type is usually the valve of choice. With regards to design criteria, velocities across globepattern valves (used for pressure reducing) should be limited to 20 ft/sec (based on nominal diameter). Globe-pattern valves are normally not suitable for raw sewage applications.
Figure 2-40: Pressure Reducing Valve 2.5.4.4.
Energy Dissipation Valves The use of energy dissipation valves at pumping stations is almost always limited to cases where it is necessary to allow a high pressure supply to enter a wet-well and it is impossible to conserve the high pressure by connecting the supply to the suction side of the booster pumps. Dissipation of energy can be achieved through the type of valves used for pressure reduction or pressure relief, i.e., globe-patterned valves, or cylinder sleeve valves. Sleeve valves are essentially two fabricated concentric or eccentric cylinders, one of which is provided with a series of holes. The outer cylinder remains stationary, while the inner cylinder is moved by a motor-operated screw to expose as many holes as necessary to reduce a variable upstream pressure to essentially zero. Sleeves valves may be installed in either the horizontal or vertical position. The most common orientation is vertical, where the valve is located in a stilling well. Unlike other types of energy dissipation valves, the sleeve valve is dynamically balanced for designed flow pressure conditions and there is essentially no vibration. Sleeve valves are not suitable for raw sewage applications or storm water applications.
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OCT 2011
2.5.5.
Air Release / Air Vacuum Valves Air release valves are frequently provided at the highest point of horizontal centrifugal pumps and on top of the discharge piping of vertical turbine pumps. These valves allow the release of air trapped in the piping, enabling the full volume of the piping to be used for conveying flow. For vertical units, the air release valve is generally located upstream of the check valve due to the large volume of air vented during start up. When vertical turbine pumps energize, the pump column and discharge head is typically full of air. This large volume of air must be vented before the flow makes contact with the check valve. In addition, for vertical turbine barrel-installed pumps a combination air release-air inlet valve (or separate valves) should be provided on top of the annular space between the pump barrel and the pump discharge pipe, especially if the normal water surface in the barrel is below the discharge head flange. Failure to install an air valve on the top of pump barrels may result in a trapped air pocket causing the level controls to be inoperable. Air release valves are designed to seat when water fills the valve body raising the float. The seating process does not happen instantly; therefore the valves expel water prior to seating. The design engineer shall include piping necessary to route the expelled water from the air release valve to a drain or back to the wet well. Air valves are also available for sewage and sludge application.
Figure 2-41: Examples of Various Air Release Valve Configurations
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OCT 2011
2.6.
System-Head Curve Development For most projects, the maximum design flow and TDH for the pump station is established and approved by the client to meet the scope of work, by way of Technical Memorandum(TM), criteria document or other means of documentation. The approved criteria should be met by the designed pumping system. The design engineer after determining the pumping system flow ranges, hydraulic grade line and materials of construction should prepare the hydraulic calculations, including friction loss, static and dynamic head losses (TDH), non-overloading horsepower and Net Positive Suction Head Available (NPSHa). The design engineer should consult with pump manufacturers to obtain the best fit pump for the determined application. Hydraulic design includes sizing the force main and developing the system head curves, which are then used to select the number and size of the pumps. Developing the hydraulic design is a significant responsibility placed on the design engineer. The sizing of the pumps drives the designs for the other disciplines. Structural and architectural develop their respective designs based on the physical size of the pumps and piping. Electrical develops their design based on the power requirements for the pump. Instrumentation and Controls discipline prepares P & I Ds and controls description in coordination with the process mechanical engineer. Any errors in the hydraulic design propagate through the disciplines creating a significant amount of rework. Due to the risk associated with rework, the design engineer should develop the design to the best of his or her ability with all available information. Then the preliminary design undergoes a peer review before being sent to the Chief Engineers for review. The hydraulic design for a pumping system is primarily conveyed visually through a system-head curve. A system-head curve is a graph which depicts the total head loss (static and dynamic) in a piping system for the full range of flow for the system. With regards to the curve, the independent variable (x-axis) is flow rate and the dependent variable (y-axis) is system head. (Typically indicated in units of GPM and FT or M3/Hr and M.) As the flow rate increases, the system head increases. Below is an example of a system curve and its characteristic shape. The pump performance curve can be superimposed on the system curve to determine the pump operating point, which is where the pump performance curve and the system-head curve cross. Coordinating with the pump manufacturer, the design engineer shall use the system-head curve to select the appropriate size and quantity of pump. The following sections describe the individual components of a system-head curve. These components are the static and dynamic head.
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OCT 2011
Intake Pump Station Total PS Flow = 144 cfs System Head Curve Flow/ pump = 12930 gpm
1200
3 - Pump @ Max Speed
1 - Pump @ Max Speed
4 - Pump @ Max Speed
2- Pump @ Max Speed
1000
High head design point = 724 ft High Static System Curve
800
TDH (ft)
5 - Pump @ Max Speed
600
400
200
Low Static System Curve
1 pump @ 875 rpm
Operating Envelope 0 0
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
90,000
100,000
Total flow (gpm) Notes: 1. Preliminary pump selection is Sulzer SJT-33NMC; 20.59" Impeller; 1180 rpm; 6 stages
Figure 2-42: Example System Head Curve
2.6.1.
Static Head The static head portion of a system curve is based on the water surface elevations at the boundaries of the pumping system (upstream and downstream). In order to convey flow from one elevation to another elevation, regardless of flow rate the minimum pressure required is the static head. This represents the pressure required to lift flow from one elevation to the next. This term is constant at all flow rates when the upstream and downstream water surface elevations are held constant. Pump stations typically operate over a range of water surface elevations at the upstream and downstream boundaries of the pumping system. The design engineer shall evaluate the systemhead curve for various operating scenarios. The worst case scenario is typically the low water surface on the upstream side of the pumping system and a high water surface elevation on the downstream side of the pumping system. These two elevations mark the point in which the static head is maximized. Furthermore, the design engineer should also evaluate the minimum static head required for the system. This occurs when the upstream water surface elevation, of the pumping system, is at a maximum and the downstream water surface elevation is at a minimum. The elevation difference between these two water surfaces is minimized. When the system curve is developed for one scenario, the design engineer can quickly generate multiple system curves based on a variety of upstream and downstream water surface elevations. The difference between two system curves for the same system, one using a high static head and the other using a low static head, is a vertical displacement. The slope and inflection point of the curves do not change. Therefore, if the design engineer has calculated the system curve at worst case scenario (low water level at the suction side of the pump station and high water level at the
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OCT 2011 discharge point) it can easily be used to generate the system curve at the lowest static head value. The curve shifts downward equivalent to the difference in the static heads.
2.6.2.
Dynamic Head The second component used in generating a system-head curve is the dynamic head. The dynamic head is more complicated as it varies with the flow rate in the pumping system. The dynamic head represents the head loss created by moving flow through the pump station, valves, fittings and piping system. This head loss increases approximately proportional to the velocity rose to a certain power. For the Darcy Wesibach velocity is raised to the 2, for the Hazen-Williams Equation velocity is raised to the 1.85. This relationship explains why the dynamic system curves always appear as a parabola. In order to determine the dynamic head for a system, the design engineer should have relevant data regarding the piping network including pipe sizes, lengths and materials, fittings, valves, fluid properties and flow operating range for the system. In the water and wastewater industries, two methods are accepted for determining the dynamic losses in a piping system. The two accepted methods are the Darcy-Weisbach and Hazen-Williams Methods. For waterworks application, MWH recommend to use the Hazen-Williams Method because it has been proven to work, is calibrated for water conveyance system and uses the friction factor “C” established by AWWA M11. Use Darcy-Weisbach for piping velocities higher than 15 fps and for viscous fluid other than water such as chemicals, polymers and others. Both methods are described in detail in the following sections.
2.6.2.1.
Hydraulic Losses: Darcy-Weisbach The Darcy-Weisbach equation is the most often used equation when calculating pipe friction losses. The equation relates head loss through the pipe to known features of the design, such as the friction factor, length of pipe, velocity of the flow, viscosity, the diameter of the pipe and the force of gravity. The Darcy-Weisbach equation is:
2 Where: hf =
friction loss, ft of liquid
L=
pipe length, ft
D=
inside diameter of pipe, ft
V=
pipe velocity of the fluid, ft/sec
g=
acceleration of gravity, 32.2 ft/sec2
f=
friction factor, dimensionless
Note, the Darcy Weisbach equation is used to calculate losses associated with the piping only. Losses associated with fittings are discussed in section 2.6.2.3. At this point in the design, the design engineer has developed the preliminary piping layout therefore; most of this information is available to the design engineer, except for the friction factor. The friction factor is a variable which depends on the fluid characteristics and the roughness of the pipe. With regards to the fluid characteristics associated with the friction factor, the design engineer must take into account the kinematic viscosity and velocity of the fluid by using the Reynolds Number. The Reynolds (Re) number is a non-dimensional value indicating of the smoothness of flow. At low Reynolds numbers (Re<2100), flow is laminar. As the Reynolds number increases (Re>4000), flow becomes turbulent. The friction factor also takes into account the surface roughness of the material. Depending on the material used for the piping, the smoothness of the pipe inner surface has a direct bearing on the amount of head loss created. Smooth pipe, such as plastics or glass have very low head loss, while concrete pipe has a much higher lead loss. One disadvantage Page | Chapter 2-56
OCT 2011 in using the Darcy Weisbach equation is how to determine the correct roughness factor for the type of pipe or lining material. The Design Engineer is encouraged to consult the pipe manufacturer for the recommended roughness factor (for concrete from 0.001 to 0.01) which have been proven and calibrated in the field. Otherwise if a conservative roughness factor is used, the TDH will be overly conservative. This surface roughness is divided by the diameter of the pipe to determine a relative roughness coefficient. By using the Reynolds number and the surface roughness of the pipe, the design engineer has enough information to determine the friction factor. For laminar flow, the friction factor can be directly calculated by using formula below: 64 For turbulent flow, the design engineer has the option of either calculating the friction factor using the Colebrook/White equation or through use of the Moody Diagrams. Both methods provide the same value for the friction factor. However, the Colebrook/White formula is an implicit equation requiring iterative solution. The Swamee-Jain, shown below, provides direct solution for friction factor value, and is accurate to within 2.5% of Colebrook equation or Moody Diagram. This explicit equation can be used when 5000
0.25 log 2.6.2.2.
5.74
3.7
.
Hydraulic Losses: Hazen-Williams Another method for determining head loss in a pipe is by using the Hazen-Williams Equation. This equation is well recognized and is water and wastewater industry accepted method used for determining head loss in pipes in the water and wastewater industries. This equation initially gained its popularity due to its simplicity compared to the Darcy-Weisbach Equation. The head loss could quickly be calculated without computers or use of the Moody Diagrams. The Hazen-Williams equation relates the pipe friction losses to the system flow rate, pipe diameter and a C-factor. The C factor, determined by experimentation, captures the effects of the roughness of the pipe. The HazenWilliams Equation is: 10,500
.
10,700
.
.
.
US Customary Units (gpm, in)
.
.
. .
SI Units (m3/sec, m)
For the two above equations, hf is given in head loss per 1000 ft (US Customary Units) of length or 1000 m (SI Units) of length As mentioned previously, the equation utilizes a C factor to account for varying pipe materials and surface roughness. C factors are determined experimentally for various pipe materials, surface roughness values and age of pipe. As can be expected, the C factors are accurate for pipe sizes and flow ranges used in the experiments. This limitation is the one drawback of using the Hazen-Williams equation. MWH typically requires head loss calculations be performed using Hazen-Williams in lieu of DarcyWeisbach. Due to the overall ease of using Hazen-Williams, it is good engineering practice for the design engineer to use the Hazen Williams and use Darcy-Weisbach method as a check. The justification for this requirement is the concern over the accuracy of the results. As stated above, the C factors are developed through experimentation for certain size pipes with specific velocities. If the design engineer is performing calculations for pipe sizes or flow velocities outside of this range, there Page | Chapter 2-57
OCT 2011 is the possibility for misleading results with the Hazen-Williams Equation. This is why; the Design Engineer is urged to bracket the head loss between the new and the old pipe. The Hazen-Williams equation should not be used for pipe sizes below 8-inches or above 60-inches. The Darcy-Weisbach Equation, on the other hand, is valid for all pipe sizes and flow velocities as long as the roughness factor is carefully determined. The design engineer shall pay special attention when using C factors for large diameter pipes. The concern regards the accuracy of the C factors. As the pipe diameters increase, the accuracy of the C factor decreases, therefore the C factor must be adjusted. AWWA Manual M11 describes the correlation for C factors and pipe diameters. For smooth internal lining in good condition, the average value of C maybe approximated by the formula C = 140 + 0.17d Piping with long term lining deterioration, slime buildup, etc, a lower design value is recommended, as follows C = 130 + 0.16d Where: D = inside diameter of piping after lining in inches Comments regarding the use of C Values:
2.6.2.3.
C values of 140 to 150 are suitable for smooth (or lined) pipes larger than 300 mm (12 in).
For smaller smooth pipes, C varies from 130 to 140 depending on diameter
C values from 100 to 150 are applicable in the transitional zone (between laminar and turbulent flow), but the scale effect for different diameters is not included in the formula
The formula is unsuitable and not recommended for old, rough or tuberculated pipes with C values below 100,
Force mains for wastewater can become coated with grease and C valves may vary down to 120 or less for severe grease deposition
C factors and ranges shall be approved by the Chief Mechanical Engineer
Hydraulic Losses: Fittings The Darcy Weisbach and Hazen-Williams equations both address hydraulic losses for the pipe only. As flow passes through fittings or valves, hydraulic losses are created. The losses are proportional to the velocity, or velocity head, of the flow. The velocity head represents the energy in the system required to move the flow at a specific velocity.
2 2 Where: V=
pipe velocity of the fluid
g=
acceleration of gravity
As can be expected, the losses experienced at the fittings and valves are directly proportional to this flow energy. This proportionality is described through a K factor. Based on experimentation, numerous types of valves and fittings have been tested to identify the K factor.
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OCT 2011 When the design engineer is calculating the system hydraulics, the dynamic losses need to include the fitting losses. A summation of K factors for each experiencing the same flow rate and velocity will provide information regarding the system losses. See the MWH Pump Station Evaluation Tool for more information regarding the use of K factors.
2.6.3.
System Curve Manipulation The system-head curve is a snap shot of the hydraulic losses in a piping system for a set of specific boundary conditions and component settings. Boundary conditions typically refer to the up-stream and downstream water surface elevations. The term component settings refer to any piece of equipment affecting the head loss through the system. If either the boundary conditions or component settings change, the system curve changes with it. The design engineer should have a clear understanding of how boundary conditions or system components affect the system curve.
2.6.3.1.
Effects of Throttling In hydraulic systems, pumps can be controlled in many different ways. Throttling the pump is the simplest way to control the pump flow rate, however it is discouraged as it is not an efficient use of energy. Throttling valves are located on the downstream side of the pump. By opening or closing the throttling valve the flow through the pump can be manipulated. The throttling valve indirectly affects the pump by directly manipulating the system-head curve. Long term throttle leads to premature wear and should be avoided. In these cases, consider using variable frequency drives. Throttling the flow can significantly change the slope of the system curve. As we discussed previously, the system curve is composed of a static element and a frictional element. The static element is constant and the frictional element increases with flow rate. The introduction of a throttling valve to the discharge side of a pump affects the frictional element. Throttling the flow increases the system losses proportional to the velocity of the flow. As a result, the slope of the system curve becomes steeper. The pump operates at a point where the system-head curve intersects the pump performance curve. As a result, by adjusting the degree of throttling, the operator has the ability to achieve a specific operating point on the pump performance curve.
2.6.4.
Net Positive Suction Head (NPSH) and Cavitation Design criteria involving the NPSH, if overlooked, could result in pump damage due to cavitation. The NPSH is a measure of the net positive fluid pressure at the entrance of the pump. (The specific reference point for the entrance to the pump is the eye of the impeller.) If the NPSH at the eye of the impeller is insufficient, cavitation will occur decreasing the pump performance and reducing the life of the pump. Cavitation is a phenomenon in which the localized fluid pressure drops below the vapor pressure of the fluid. On a microscopic level, the fluid vaporizes forming a bubble. As the bubble moves further into the pump, the surrounding pressures increase causing the bubble to collapse. The collapsing bubble initiates a shockwave which propagates through the fluid. These shockwaves deteriorate the material surface of the impeller. The extent of cavitation can be severe enough to decrease the pump performance and significantly increase the equipment vibration levels. It is very difficult to determine when cavitation actually starts. Many tests and observations conducted by members of the Hydraulic Institute have concluded that cavitation starts as early as 1% drop in head. The Hydraulic Institute’s definition of pump cavitation occurs when damaging cavitation starts. This occurs when the performance of the pumps drops by 3%. MWH recommends a minimum margin of 5 ft between the NPSHr and NPSHa or NPSHa =/>NPSHr + 5 ft.
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OCT 2011
Figure 2-43: Cavitation Damage 2.6.4.1.
Theoretical Discussion of NPSH The Hydraulic Institute defines NPSH as the total suction head in feet absolute, determined at the suction nozzle and corrected to datum, less the vapor pressure of the liquid in feet absolute. Simply stated, it is an analysis of energy conditions on the suction side of a pump to determine if the liquid will vaporize at the lowest pressure point in the pump The pressure which a liquid exerts on its surroundings is dependent upon its temperature. This pressure, called vapor pressure, is a unique characteristic of every fluid and increases with increasing temperature. When the vapor pressure within the fluid reaches the pressure of the surrounding medium, the fluid changes phase, from liquid to gas. The fluid will appear to vaporize or boil. The temperature at which this vaporization occurs will decrease as the pressure of the surrounding medium decreases. The volume occupied by the gas phase is significantly greater than the volume occupied by the liquid phase. One cubic foot of liquid water at room temperatures becomes 1700 cubic feet of water vapor at the same temperature. This volume difference is what is responsible for the collapsing bubbles as the vapour bubble changes phase back to liquid. It is obvious from the previous discussion that if we are to pump a fluid effectively, we must keep it in liquid form. Another way to interpret NPSH is a measure of the amount of suction head present to prevent this vaporization at the lowest pressure point in the pump. NPSH required is a function of the pump design. As the liquid passes from the pump suction to the eye of the impeller, the velocity increases as the pressure decreases. There are also pressure losses due to shock and turbulence as the liquid strikes the impeller. The centrifugal force produced by the impeller vanes, further increase the velocity and decrease the pressure on the liquid. The NPSH required is the positive head in feet absolute required at the pump suction to overcome these pressure drops in the pump and maintain the liquid above its vapor pressure. The NPSH required varies with speed and capacity within any particular pump. Pump manufacturer’s curves normally provide this information. The NPSH available is a function of the system in which the pump operates. It is the excess pressure of the liquid in feet absolute over its vapor pressure as it arrives at the pump suction. Figure 2-44 shows four typical suction systems with the NPSH available formulas applicable to each. It is important to correct for the specific gravity of the liquid and to convert all terms to units of “feet absolute” in using the formulas.
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OCT 2011
Table 2-8: Water Vapor Pressures at Various Temperatures Temperature °F
Pressure of Saturated Vapor (psi abs)
Temperature °F
Pressure of Saturated Vapor (psi abs)
32 40 50 60 70 80 90
0.089 0.122 0.178 0.256 0.363 0.507 0.698
100 120 140 160 180 200 212
0.949 1.693 2.889 4.741 7.511 11.526 14.696
Figure 2-44: Calculation of system NPSHa for typical suction conditions Excerpt from Goulds/ITT Pumps
Page | Chapter 2-61
OCT 2011 2.6.4.2.
Practical Discussion of NPSH The NPSH available to a centrifugal pump combines the effect of atmospheric pressure, water temperature, supply elevation and the dynamics of the suction piping. The following equation illustrates this relationship. All values are in feet of water because this is easy to determine from drawings or installations. The sum of these components represents the total pressure available at the pump suction, NPSHa. NPSHa = patm / γ + hz - hf - pv / γ NPSHa = hatm +/- hz - hf – hvp Where: hatm = hz =
hf = hvp = γ =
the atmospheric or absolute pressure, ft. the vertical distance from the surface of the water to the pump impeller eye centerline. This value can be positive or negative, depending on the relative location of the water surface elevation to the pump impeller eye, ft the friction head created by the suction piping, ft the vapor pressure of the water at its pumping temperature, ft Specific weight of water, 62.4 lbs/ft3
Table 2-6 below indicated atmospheric pressures at various altitudes. Table 2-9: Atmospheric Pressures or Barometric Pressure at Different Altitudes
2.6.4.3.
Altitude (Feet)
Atmospheric Pressure PSI ( FT )
-1000 -500 0 500 1000 2000 3000 4000 5000 6000
15.2 (35.2) 15.0 (34.7) 14.7 (34.0) 14.4 (33.4) 14.2 (32.8) 13.7 (31.6) 13.2 (30.5) 12.7 (29.4) 12.2 (28.3) 11.8 (27.3)
Altitude (Feet)
Atmospheric Pressure PSI (FT)
7000 8000 9000 10000 15000 20000 30000 40000 50000
11.3 (26.2) 10.9 (25.2) 10.5 (24.3) 10.1 (23.4) 8.3 (19.1) 6.7 (15.2) 4.4 (10.2) 2.7 (6.3) 1.7 (3.9)
Discussion of NPSH Required (NPSHr) and NPSH Margin The previous section states if the NPSH available to the pumps is not adequate, cavitation occurs. Adequate refers to the margin between what is available and what is required by the pump. Based on historic test data, manufacturers determine the minimum NPSH necessary at the impeller eye to comply with HI’s definition of minimum NPSH for a pump. This minimum NPSH necessary is called the NSPH Required (NPSHr). NPSHr information is typically represented on the pump manufacturer’s performance curves. The curve is identified as the NPSHr curve and typically increases slightly with the flow for a majority of the operating range. At pump run out, however, the NPSHr curve becomes parabolic and increases significantly. The design engineer shall not only verify the NPSH margin at the design point, but also at the maximum flow operating point. The design engineer shall confirm the NPSH available is greater than the NPSH required by at least 5 feet for normal water and wastewater applications. The 5 ft margin is only applicable at the design point. For some applications (e.g., high-temperature fluids and volatile liquids), the
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OCT 2011
NPSH margin should be greater. Note Hydraulic Institute Standards require only 3 feet, but MWH recommends 5 feet based on project history and experience.
2.6.5.
Minimum Submergence Minimum submergence is used to describe two distinct requirements when it comes to pumps. It is the design engineer’s responsibility to verify that the installation complies with both requirements. First requirement is NPSHa varies as a function of submergence above the pump datum. Due to the NPSH required by the pump, each pump has an equivalent minimum water surface elevation to meet the NPSH requirements (including the 5 ft margin). The second requirement is typically seen with vertical turbines and suction flared elbow for dry pit non-clog and horizontal split case pump, and accounts for the creation of surface vortices. Surface vortices are related to the submergence above the suction bell (for vertical turbine pumps). The physics of spinning the impeller just below a free water surface creates a swirling effect around the pump. This swirling action has the potential to create smaller vortices and draw an air cone into the pump suction. For pump station designs, the design engineer shall not only verify the minimum submergence for NPSH, but also the minimum submergence to prevent surface vortices that could be drawn into the pump suction. This minimum submergence to prevent surface vortices could be less than or greater than the submergence required to meet the NPSHr. This information is usually indicated on the pump curve for vertical turbine pumps or available from the pump manufacturer.
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OCT 2011
2.6.6.
Hydraulic Grade Line System-head curves are typically used to select pumps for a specific service. They indicate the maximum pump TDH at the pump station for the entire flow range. These curves are essential when selecting pumps and evaluating the pump station. In addition to understanding system curves, the design engineer needs to understand the hydraulics of the suction and discharge pipeline. System curves do not address the pressures occurring through the pipe line. To analyze the pipeline, a design engineer must create a hydraulic grade line. A hydraulic grade line is a plot of the local pressure in the pipeline (where pressure is indicated in units of feet) versus the horizontal displacement along the pipeline. This information is visually shown on the pipeline profile drawing by including a line at an elevation corresponding to the pressure in the pipe. For example, if the centerline of the pipeline is at an elevation of 1000 ft, and the pressure in the pipeline is 250 ft, then the hydraulic grade line is draw at 1250 ft. For a relatively flat pipeline, pressures are highest adjacent to the pump station, and continuously decrease to and join the free water surface at the discharge location. See the following example of pumping system hydraulic grade line.
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OCT 2011
Figure 2-45: Pumping System Hydraulic Grade Line
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OCT 2011
2.7.
MWH Pumping System Evaluation Tool (PSET) The hydraulic calculations necessary for the system-head curve and pump curve manipulation are very comprehensive and difficult to check. In order to establish a method of producing consistent and accurate calculations to meet the needs of the engineer, MWH has developed a proprietary tool to aid the design engineer. The MWH Pumping System Evaluation Tool (PSET) allows the user to create system-head curves and manipulate pump curves in order to analyze the pumping system.
2.7.1.
Introduction Pumping System Evaluation Tool (PSET) is a Microsoft Excel based program, developed by MWH for its own use, specifically designed for evaluating typical pumping systems in MWH’s core Water business. The use of this tool or other approved MWH hydraulic calculation tools such as PIPEFLO is required by MWH Americas for performing a thorough pumping system analysis and the hydraulic selection of pumps. A PSET guide is available to assist Users through the process of analyzing various pumping system configurations, such as single and multiple pump operation at steady state conditions. This process utilizes industry standard methodologies for the calculations and analysis. The methodology and equations have been verified for accuracy. The tool ultimately produces and graphical representation of the hydraulic system head and pump performance curves in the format required by the MWH America’s Chief Mechanical Engineer.
2.7.2.
Purpose The purpose of this tool is to provide a standard approach for evaluating and designing of pumping systems throughout MWH Americas. By standardizing the process of approach, the methods and assumptions have been reviewed for accuracy. Utilizing this tool limits liability associated with improperly checked templates. PSET allows the USER and REVIEWER to focus on the design of the system and not on the development and checking of common procedures, assumptions and calculations.
2.7.3.
Assumptions The tool is valid for any single phase flows of Newtonian, steady state incompressible fluids in a linear (non-looped) model. This tool does not address issues associated with transient flow conditions and surge which should be considered for every pumping system. At this time, this tool is only setup for US customary units.
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OCT 2011
2.8.
Sludge Pumping The following section provides a summary for the approach to pumping wastewater and water treatment plant sludges. Other pumpable materials such as chemical slurries, ash, grit and screenings are not covered and would require a case by case investigation and consultation with equipment suppliers and specialists. The principle problem with handling sludge is the variability of the material and the resulting impact on hydraulics. In addition, there may be unique problems associated with starting sludge systems, both in overcoming inertia and the solids like characteristics of certain sludges when they are stationary plus problems of assuring satisfactory delivery to the pump suction. In some instances, such as handling screened return biological sludges (with less than 2 percent solids) the hydraulics of pumping sludge may be very similar to handling water or raw sewage. With thicker sludges, however, the hydraulics is often different, head losses (friction) are higher and pumping equipment selection is significantly different. For positive displacement pumps there are (unlike centrifugal pumps) compelling reasons to add safety factors to estimated head. Before undertaking the task of establishing design criteria for sludge pumping applications, it is essential to read and become familiar with Chapter ”System Design for Sludge Piping”, Pumping Station Design, Robert L. Sanks, Butterworth, 1989. Note the summary of sludge characteristics and classifications outlined in Tables 2-10 and 11.2. Note that Class A and Class B sludges may be regarded as raw water or sewage. Refer to previous sections for guides to pump selection and hydraulics.
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OCT 2011
Table 2-10: Liquid Sludge Classification Percent Range
Solids Typical
Class
Comments
0.5 – 1.0 2.0 – 6.0 5.0 – 9.0
0.5 4.0 6.0
B C C
Handle as raw sewage Higher head losses Laminar flows – see text
Biotower and Trickling Filter Sludges
0.3 – 0.7
0.5
A
Hydraulics similar to raw water
Waste Activated Sludge
0.3 – 1.0
0.5
A
Hydraulics similar to raw water
Thickened Biological Sludges Dissolved Air Float w/o Polymer Dissolved Air Float w/ Polymer Gravity Belt Thickening Centrifuge Thickening
3.5 – 5.0 4.0 – 6.0 5.0 – 9.0 4.0 – 7.0
4.0 5.0 6.0 5.0
C C C C
See Table 2-11 See Table 2-11 See Table 2-11 See Table 2-11
10.0 – 25.0
20.0
D
Special consideration, see Table 11
1.0 2.0
A C
See Table 2-11 See Table 2-11
15
D
Pump Table
22
D
May require moisture
Gravity (Lagoon) Thickened
0.5 – 2.0 0.5 – 4.0 10.0 – 20.0 20.0 – 25.0 3.0 – 6.0
5.0
C
See Table 2-11
Lime Sludges Continuous Withdrawal
0.5 – 4.0
2.0
B
Intermittent Withdrawal
1.0 – 10.0
6.0
C
Gravity Thickened
5.0 – 10.0
8.0
C
Characteristics vary May require resuspension May require resuspension
Description WASTEWATER TREATMENT Primary Sludges Continuous Withdrawal Intermittent Withdrawal Thickened
Secondary Sludges
Dewatered (Digested)
WATER TREATEMENT Alum Sludges1 Continuous Withdrawal Intermittent Withdrawal Centrifuge Thickened Belt Thickened
25.0 – --Non pumpable 70.0 1 Ferric sludges and sludges derived mainly from polymers may tend to have solids contents slightly higher than alum sludge. Centrifuge Thickened
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OCT 2011
Table 2-11: Sludge Handling Classification
2.8.1.1.
Classification (See Table 2-10)
Comments on Hydraulics and Pumpability
A
May be handled as raw water but check to ensure that rags and plastic materials will be absent. Use centrifugal pumps. May be pumps 50 miles (80 km).
B
May be handled as raw sewage. Use non-clog centrifugal pumps. Do not use butterfly valves. May be pumped 50 miles (80 km).
C
Utilize Fig 2-39, Pipe Friction of Sludges Headloss Prediction for Worst-Case Design to compute head loss plus solids percent safety factor. Provide water flush to suction side of pump. Utilize positive displacement pumps. May be pumped moderate distances.
D
Requires concrete type pumping equipment, very high heads, to 1000 psi (7000 kPa). Maximum pumping distance limited to onsite transfers. May require rewetting. Investigate in depth. Consult with equipment suppliers. Conduct field trials.
Hydraulics of Sludge Pumping (Class C & D) The hydraulics of handling sludge with less than 2 percent solids is essentially the same as water or sewage. Some allowance may be appropriate for grease build up but be cautious not to overestimate total dynamic head. Hydraulic computations may be based on water (increase friction losses by 5 percent) but utilize median conditions for static lift for low-head applications (less than 20 feet (6 meters)) be sure to include velocity head in total dynamic head. For sludges with more than 2 percent solids, however, the pattern of flow is often laminar but the head losses (friction) may be 5 to 100 times higher than equivalent turbulent flow water losses. Figure 11-1 herein provides a guide for the computation of friction losses for Class C sludges. The figure indicates that the data is for “worse-case” predictions. For positive displacement pump applications, however, it is advisable to add a safety factor to the data. An appropriate safety factor would be to raise, by one third, the estimated percentage of solids to be pumped. The use of Mulbarger’s design curves involves the computation of head losses in the piping system based on normal hydraulic analyses. (Hazen-Williams or Darcy-Weisbach formulas are both applicable). After the normal water head losses are computed, they should be corrected to estimated sludge losses by use of the Mulbarger factors (Figure 2-47)
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OCT 2011
Figure 2-46: Friction Loss Multiplier for Various Sludges
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OCT 2011
Figure 2-47: Pipe Friction of Sludges Headloss Prediction for Worst-Case Design
Page | Chapter 2-71
OCT 2011 Analysis of the Mulbarger data indicates that for a given pipe diameter there is no significant increase in friction with increases in velocity. For sludge pump applications, therefore, system head curves are not appropriate and estimation of total dynamic head (friction plus static lift) plus a safety factor is appropriate for estimating design head. Typical velocities for sludges, 2 to 10 percent solids (Class C) are in the range of 1.5 to 3.0 fps (0.5 to 1.0 m/s) for dewatered sludges (10 to 25 percent solids) velocities of 0.3 to 0.6 fps (0.1 to 0.2 m/s) may be applicable. For dewatered sludges (10 to 22 percent solids) see Figure 2-46 for pipe friction criteria. (Note that recommended velocities are based on maximum velocity and not average velocity. See comments on flow characteristics of reciprocating pumps). Particular attention also needs to be given to certain features of piping, fittings and valves. a. Consideration should be given to smooth pipe linings such as glass, epoxy (or in some instances, stainless steel). For applications where maximum discharge pressures do not exceed 100 psi (700 kPa) PVC pipe and fittings may be appropriate, except in cases where steam cleaning is possible. b. Use long radius bends where possible. Avoid tees (use “wyes” and 45 degree bends if possible). c. Use full-port valves such as ball valves, knife-gate valves, cone valves, ball valves or solid wedge gate valves. Do not use globe pattern valves or butterfly valves. Check valves should be swing check valves mounted in the horizontal position.
Figure 2-48: Pipe Friction, Dewatered Sludge (20-22% Solids)
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OCT 2011
Table 2-12: Sludge Pumping Distance Sludge Type Liquid Liquid Liquid Liquid Dewatered
1 Percent Solids 2 Percent Solids 5 Percent Solids 10 Percent Solids 20 Percent Solids
Classification
Max Distance
A B C C D
50 miles (80 km) 50 miles (80 km) 5 miles (8 km) 1 mile ( 1.5 km) 500 ft (150m)
The maximum distance that sludge may be pumped (by a single pumping facility) will be limited by pressure considerations and percentage solids. Table X provides a guide for the maximum pumping distance of various sludges. The above guidelines should not be exceeded unless client experience or field test indicate otherwise, and criteria committee approval is specifically obtained. 2.8.1.2.
Water Flushing Consideration should be given to water flushing provisions for applications where it is possible for sludge to be in excess of 4 percent solids and for all air and vacuum valves utilized for sludge handling systems. (Sludge piping systems should be tested with water prior to priming with sludge. The provision for filling (and draining) with water will dictate the location of air and vacuum valves.) The principle purpose of water flushing is to assure that sludge (on the suction side) may be liquefied prior to starting operations. Water flushing on the suction side may be essential for ensuring reliable startup with thickened biological sludges (or any sludge that may contain more than 4 percent solids under any foreseeable conditions). Provisions for manual water flushing on the discharge side of the pump and at intervals along a pumping main should be considered for cleaning and removing thickened sludge if there is a blockage or for decreasing solids content under unanticipated conditions. For major sludge transfer stations (installed total motor rating in excess of 20 HP (15 kW) or for off-site pumping mains in excess of 2000 feet (600 mm) or where directed by the client and or in cases where starting pumping is an operational problem, consideration should be given to automatic suction flushing. Such systems should provide for a water flush connection (capacity approximately equal to pump design capacity) to the suction side of operating sludge pumps. Controls should provide for flushing for 30 seconds prior to starting and prior to stopping pumps. On long pumping mains (off-site) it may be necessary to provide a parallel pressure water line for flushing air valves and for unclogging and maintenance. The design of off-site sludge pumping mains requires very detailed investigations and environmental analyses to determine the risks and impacts of line breakage and releases of sludge to the environment. In general pumping lines must be capable of being drained to the origin sump, receiving point, to sanitary sewers or to sumps that can contain the volume of the pumping main. Such sumps must be capable of being legally drained or otherwise emptied by pumper trucks.
2.8.1.3.
Sludge Pumping Equipment Sludges vary from homogenous, watery, soup-like liquids to viscous, non-homogenous semisolid materials. Consequently, there is a broad range of pump applications. Also, because pumping heads, may vary significantly, pumps that can tolerate a wide band of head conditions are often required. Centrifugal pumps are not suited for variable head applications and are, therefore, only suitable for low-solids, predictable quality sludges. A summary of available pumps and their application to previously-listed sludge classifications is included in Table 2-13. The following section describes the specific application of various pumps for conveying sludge. For a more general application of pumps, see Section 3.
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OCT 2011
Table 2-13: Sludge Pump Application Classification Type of Pump
Sludge Application Classification A
B
C
D
a.
Centrifugal Pumps
X
--
--
--
b.
Turbine Pumps
--
--
--
--
c.
Non-Clog Centrifugal
X
X
--
--
d.
Torque-flow Pumps (Recessed Impeller)
X
X
--
--
e.
Plunger Pumps
--
X
X
--
f.
Piston Pumps
--
X
X
--
g.
Progressive Cavity Pumps
--
X
X
--
h.
Diaphragm Pumps
--
X
--
i.
Rotary Lobe Pumps
--
X
--
--
j.
Hydraulic Piston Pumps (Concrete Pumps such as Putz-meizer Pumps)
--
--
--
X
a. Centrifugal Pumps. For sludge pumping applications, centrifugal pumps may be utilized for Class A sludge that has been screened and/or thin water treatment plant sludges. All configurations (horizontal, vertical and submersible) may be utilized. b. Vertical Turbine Solids Handling Pumps by Fairbanks-Morse. For sludge pumping applications, vertical turbine pumps may be utilized for Class A sludges that do not contain any stringy materials such as rags or plastics. Generally turbine pumps are not used for handling primary wastewater sludges but they may be used for thin secondary and tertiary treatment (Class A) sludges and water treatment sludges. Conventional and submersible configurations may be utilized. c. Non-clog centrifugal pumps may be used for Class A & B sludges. They may be utilized in all configurations (horizontal, vertical and submersible). Caution should be exercised to ensure that motors will not be overloaded because of higher specific gravity or viscosity. d. Torque-flow (recessed impeller) pumps are also known as vortex pumps. They have an open impeller designed to pass solids and to minimize wear. They are essentially centrifugal pumps. They are normally installed in a horizontal position. They are ideal for Class A&B sludges and may be used for Class C sludges if the percentage of solids will not exceed 4 percent. e. Plunger pumps are piston pumps, with an exposed drive crank. The eccentricity of the crank is adjustable and the capacity of the pump may be varied by stroke adjustment (and speed adjustment). Plunger pumps are positive displacement pumps and can be operated over a range of heads from zero to design head. There are one adverse operating head conditions within the total possible range of heads (zero to maximum) and power input is approximately proportional to operating head. Plunger pumps are suitable for Class A, Class B and C sludges and may be used for Class D sludges if the percentage of solids does not exceed 15 percent. Plunger pumps may be operated with a suction lift of not more than 10 ft (3 m). There is some risk of surging of sludge (and resulting compaction). Multiple piston units reduce surging impacts. The pumps may require daily inspection and also may require flushing water connection for seals and priming.
Page | Chapter 2-74
OCT 2011 Piston pumps are similar to plunger pumps but are more refined and may include such features as piston guides, hydraulic drive and enclosed crank shaft. They may be speed controlled and require less attention than plunger pumps. On the other hand, they are more expensive than either plunger pumps or progressive cavity pumps. They are suitable for handling Class A, B and C sludges but their primary application is for feeding thickened sludges to filter presses. g. Progressive cavity pumps are the preferred selection for handling Class B and C sludges [In the US, Robbins and Myers (Moyno) pumps are the most accepted manufacturer]. They may be installed for fixed speed, intermittent operation or variable speed applications, if consistent feed is preferred. Progressive cavity pumps include a stator made of resilient material, such as rubber, and a stainless steel or specially plated helix rotor. They are normally installed in a horizontal configuration. Three feet (0.9 meters) of submergence should be provided on the suction side. Avoid suction lift conditions if possible. If existing conditions force you to consider a suction lift, arrange pump so that the stuffing box or seal is on the discharge side of the pump so that air leakage through seal will not cause suction vacuum to fail. Check with manufacturer. Although progressive cavity pumps are reliable and relatively maintenance-free, stator wear is a problem. It can be minimized by up-stream grit removal but also by minimizing the head per stage. In order to compensate for the wear and tear of the stator, it is recommended to specify a minimum of 2-stage rotor and stator even though the pressure rating do not require 2-stage pump. As a conservative guide, provide one stage per 25 psi (175 k Pa). Pump speed should not exceed 250 rpm. Specify motor ratings 50 percent higher than indicated under pump design conditions. Where adequate suction head is furnished, progressive cavity pumps provide accurate and repeatable capacity characteristics. They may be utilized for metering functions. For further details of progressive cavity pumps, refer to MWH standard specification 43 22 33. h. Diaphragm pumps (ODS) (pulse transfer systems) utilize an air or hydraulic fluid on one side of a flexible diaphragm to push “pulses” of liquid out of a cavity. Check valves on the suction and discharge side of the pump are essential and critical components. Diaphragm pumps may be utilized for handling Class C sludge. Some clients may require them, but they generally are not as accepted as progressive cavity pumps and are limited in capacity and head. The pulsing action may causes thickening on the suction and/or discharge side of the units. [The principle supplier in the US is Dorr-Oliver]. i. Rotary pumps (or rotary lobe pumps) are similar to rotary lobe air blowers. The pumps are positive displacement type units that comprised essentially of two enclosed and synchronized rotating lobes that form cavities between the lobe and the enclosure and force the liquid from the inlet side of the enclosure to the outlet. For sludge application, speeds are low. Provide 3 feet (0.9 meters) of submergence on the suction side. Rotary pumps are an alternative to progressive cavity pumps but they do not have the same level of acceptance. The principle manufacturer in the US is WEMCO pump. j. Hydraulic piston pumps (concrete pumps) are heavy-duty, high pressure reciprocating pumps that can be applied to transferring viscous (Class D) sludge with solids contents to 22 percent. They are expensive, but may be preferred to screw conveyor systems. Dewatered sludges (1022% solids) may be pumped for distances of 500 feet (150 m). Starting conditions are critical and suction water flushing should be provided. Before proposing pump of Class D sludge, thorough consultation with equipment manufacturers should be undertaken to ensure that the application would be reliable and that similar applications utilizing identical model pumps are operating satisfactorily.
f.
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OCT 2011
Figure 2-49: Typical Progressive Cavity Pump Layout (Plan View) 2.8.1.4.
Appurtenances The following section describes ancillary equipments typically encountered in sludge pumping systems. The ancillary components are:
Valves
Meters
Density Meters
VALVES Valves for sludge applications may be divided into two groups:
Class A & B sludges. Eccentric plug valves and gate valves.
Class C & D sludges. Full port diameter valves including ball valves and gate valves
In general, butterfly valves should not be used on any application where there could be rags, stringy materials, and plastics. Gate valves of solid wedge type, eccentric plug valves, ball valves or bonneted knife gates are recommended for sludge service. METERS Venturi meters may be used for Class A & Class B sludges. Venturi throat velocities from 3 to 20 fps (6.25 m/s) may be necessary (at maximum flow rates) to develop adequate pressure differentials. On small capacity systems, small throats may be a potential clogging problem. Metering of sludges with magnetic flow meters can be difficult because of grease (for primary wastewater sludges) and because of the need for relatively high velocities for viscous sludges. Teflon liners with ultrasonic cleaning are available to minimize build up of grease inside the meter. Magnetic flow meters should not be used on Class C & D sludges. If line velocities are low, less than 5 fps (1.5 meters per second) accurate flow measurement may be difficult. Calibrating the known capacity of progressive cavity pumps may be the most reliable measuring devise available. DENSITY METERS Where densities of sludge may exceed 3 percent solids, two types of density meters are commonly used.
Nuclear density gauges
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OCT 2011
Ultrasonic density gauges
Optical type meters
Optical type meters are also available but they are usually utilized for low (less than 3 percent) range. Ultrasonic density meters are less expensive than nuclear gauges and avoid the safety concerns of the radioactive materials that are used in nuclear gauges. Ultrasonic meters may be mounted on pipe sections and can monitor flows on a continuous basis. The meters can be coupled to flow meters so that the weight of total solids can be computed.
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OCT 2011
2.9.
Pump Control Philosophy Pump stations in the water and wastewater industries are designed to be flexible with regards to flow rate. These stations service local communities and could experience large variations in flow from peak hours to off-peak hours. As a result, stations are not designed to convey one flow rate, but a range of flow rates. In order to design a system which is flexible, the design engineer must consider how the pumps are controlled. The pump control philosophy is divided into three main categories.
Level Control
Flow Control
Level with flow feedback loop as secondary control
Pressure Control
Each category requires different instrumentation and control equipment. Furthermore, some pumps are better suited for one control method over another. The following sections describe each of the main control strategies. The design engineer shall work closely with the Instrumentation and Controls group to ensure the client’s expectations are met. See Section 4.2 Instrumentation and Controls for equipment typically used in these control philosophies.
2.9.1.
Level Control Level control is the most common method for controlling pumps. This philosophy involves controlling the pump based on the free water surface elevation in the wet well. An introduction and sample calculations for this section area included in Section 2.3.1.2 as flow enters the wet well, the water surface elevation rises. There are two types of level control, a) Fill-and Draw; b.) Flow-Match Constant Level Control.
Fill-and Draw Level Control using constant speed pumps At a predetermined level, the pump energizes and operates at full speed. If the water surface elevation drops, the pump eventually turns off. However, if the free water surface continues to rise, the next pump turns on. When the level drops, the pumps will be controlled in the reverse order. An automatic alternator will sequence the pumps so that the last pump to start would be the last pump to stop in order to make the cycle time of the pumps longer and distribute the running hours more evenly. See section 2.3.1.2 Design Considerations regarding cycling pumps in a wet well. The following is an example of a level control strategy where pumps are designed to energize in 1-foot increments.
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Table 2-14: Example Level Control Strategy Set points Control Initiated
Elevation (ft)
Rising Water Level
Falling Water Level
18.0
Overflow Alarm
---
15.5
High-High (All Pumps Including Standby Start
---
14.5
Pump #5 Start (4th Lag)
---
14.0
---
Pump #5 Stop (4th Lag)
13.5
Pump #4 Start (3rd Lag)
---
13.0
---
Pump #4 Stop (3rd Lag)
12.5
Pump #3 Start (2nd Lag)
---
12.0
---
Pump #3 Stop (2nd Lag)
11.5
Pump #2 Start (Ist Lag)
---
11.0
---
Pump #2 Stop (Ist Lag)
10.5
Pump #1 Start (Lead)
---
8.5
Low-Low (Lead Pump Shut-Down)
Low-Low (Lead Pump Shut-Down)
Flow-Match Constant Level Control
This type of control is usually used in applications such as a lift station or plant influent pump station where the incoming flow into the wet well is pumped at the same rate as the incoming flow in order to maintain a constant volume. Variable speed driven pumps are used and controlled by the wet well level. The wet well level usually has a certain band where the pumps operate within that dead band. From a preset level in the wet well, the lead pump is energized and operated from zero to a minimum speed. If the wet well level starts to rise, the pump speed will increase to deliver the same amount of flow as the incoming flow until the level is maintained. When the pump reaches its 95% speed, the first lag pump shall start and increases speed passed the minimum, while the lead pump decrease speed due to falling level until the two pumps match speed to share the load to match the incoming flow. The second lag pump will operate in the same sequence as the first lag pump as additional flow is needed to be pumped. Decrease in the incoming flow will cause the level to drop and the pumps shall operate in the reverse order until the first pump to start, will be the last pump to stop.
2.9.2.
Flow Control Controlling the pump operation based on the pump station discharge flow rate is another control philosophy used. This philosophy relies on signals from a downstream flow meter to determine if the station is operating at the correct flow rate. This type of control is usually used for water treatment influent pump station where the water distribution orders certain flow to be treated for that particular period during the in anticipation with the drinking water demand. If the instantaneous flow rate though the flow meter is above or below a desired flow rate, the control system speeds up or slows down the operating pump units, or could energize or shut down a new unit. This type of control would require either a constant speed or variable speed drive pump depending on the flow turndown ratio. If the turndown ratio is infinitely variable, then VFD driven pumps are required. Under this control Page | Chapter 2-79
OCT 2011 philosophy, the storage in the forebay such as the Lake, River or very large must be sufficient to provide adequate wet well water surface elevations (submergence) for all flow conditions.
2.9.3.
Pressure Control The system discharge pressure can also be used to control the pump operation. This type of control philosophy is typically used for a pressurized distribution system with a hydro-pneumatic tank where it is essential to maintain constant pressure usually in a closed loop system. When the flow demand increases, the system pressure decreases and more flow are required to be pumped to maintain pressure. Conversely, as the flow demand decreases, the pressure will increase and less flow is required to be pumped to maintain pressure. A change in the distribution system pressure, the pumps shall be controlled to maintain pressure energizes or increases in speed. This type of control would usually require VFD driven pumps or constant speed pumps with a bypass relief valve to trim excess flow. The later is not as energy efficient as the VFD driven pumps. The design engineer shall avoid running the VFD at speeds less than 40% of full speed. Note the storage capacity shall be infinite such as the treated water conveyance pipeline so that the water level in the wet well needs to be maintained at an adequate level at all times. Similar to a flow controlled system discussed previously.
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2.10.
Hydraulic Transient Analysis Hydraulic transient analysis, preliminary or detailed surge analysis is required for all pressurized pumping systems with static head of greater than 50 feet, flows in excess of one mgd and velocity greater than 5 fps. The design engineer shall always seek advice from a Senior Hydraulics Specialist if surge analysis is required or not. The following sections provide a brief summary of hydraulic transient analysis. It is meant to introduce the topic of transient analysis to the design engineer. This is not a comprehensive discussion regarding all aspects related to transient analysis. The design engineer should NOT perform a transient analysis without the supervision of the Senior Hydraulics Specialist. During steady state (normal) operation, the pump station adds energy to the water to move it from one location to the other. If the system abruptly changes, the energy in the water has the potential to create extremely high and low pressures, or surges. These hydraulic surges have been known to cause catastrophic failures of pump stations and pipelines. Hydraulic transient pressures are not the same in every system and that is why surge protection system should be determined as a result of rigorous hydraulic transient or surge analysis. It is the intent of every pumping system design to use the simple, safest, economical but extremely reliable type of surge protection system.
2.10.1.
General – Hydraulic Model In general, the continuity and momentum equations are the primary equation used to predict transient flow conditions. When coupled, these equations form a pair of quasi-linear hyperbolic partial differential equations in terms of two dependent variables, velocity and HGL, and two independent variables, distance along the pipeline and time. To solve these equations, MWH uses one of two software applications, H20surge or TransAM. The software modeling application called H20surge is distributed by MWHSoft, and is an add-on feature to H20net. H20surge utilizes the Wave Characteristic Method (previously published as the Wave Plan Method) to numerically solve the continuity and momentum equations. This model methodology provides a very rapid solution for large, looped systems, such as water distribution systems. The second application, TransAM transforms both equations into four ordinary differential equations by the characteristics method. The program was developed by Professor Bryan Karney at the University of Toronto and is based on the method of characteristics and forms the core of the surge analysis program used for analysis in pipelines.
2.10.2.
Primary Causes of Transient Pressures in a Pumped System Hydraulic transient pressures in a pipeline system are caused by a sudden change of flow velocity resulting from either normal or abnormal conditions in the system. Normal flow velocity changes can be caused by opening or closure of a valve, or a normal startup or shutdown of the pump station. Abnormal flow velocity changes typically result from a rapid closure of an in-line valve or a sudden uncontrolled shutdown of a pump station during a power outage. Each of these situations is briefly discussed below.
2.10.3.
Normal Flow Pump Station Startup. In normal operations, pump startups follow an orderly, predetermined procedure. When a pump is energized, a positive hydraulic transient pressure (pressure rise or upsurge) is generated in the discharge pipeline as the flow velocity increases. The magnitude of the upsurge varies with the rate of change of the flow increase. High upsurges are not normally generated by normal pump startups; as long as the flow increases steadily, the pump shutoff head is not exceptionally high, and there are no air pockets in the pipeline. If Variable Frequency Drives (VFD) is used, the VFD controls equipment startup by allowing the pumps to ramp up slowly through a two-stage startup procedure. Where the first stage ramps the VFD to the static head condition and then the second stage slowly ramps the VFD to the desired operating head and flow condition. If Page | Chapter 2-81
OCT 2011 constant speed pumps are used, a pump control valve is highly recommended. This valve should be installed to startup the pump and slowly introduce flow to the system in a similar fashion to VFD startup. Surge control devices (e.g. hydro-pneumatic pressure vessel, flywheel, and slow opening control valve) can also improve normal startup conditions by dampening the initial upsurge pressures. Note: Reduced Voltage solid state starters (soft-start units) are another option to use on constant speed pump motors. Pump Station Shutdown. In normal operations, pump shutdown also follows an orderly, predetermined procedure. The shutdown procedure allows the flow rate in the pipeline to slowly decrease. Under these conditions, the pipeline does not experience uncontrolled pressure drops, and therefore does not experience a significant down surge or adverse hydraulic transient pressure drops. An uncontrolled pump shutdown may result in a down surge followed by a high upsurge in the pipeline. Again, if a hydropneumatic pressure vessel is present, the tank mitigates transient pressures on the discharge side of the pump station during a normal pump station shutdown. Valve Operation. Rapid closing or opening of an in-line valve in a pipeline is a potential source of surge in a system. Rapid closure of a valve could generate a sudden pressure rise upstream of the valve as the flow velocity rapidly decreases. Whereas, a rapid opening of a valve could cause a sudden upstream pressure drop which propagates throughout the pipeline system resulting in unacceptable down surge or vacuum pressure conditions. Under normal operation, no valve should be closed or opened rapidly. For instance, isolation valves installed in a long pipeline requires a closing time of no less than 15 minutes.
2.10.4.
Abnormal Flow Pump Station Power Failure. A pump suddenly stopping due to power failure generally causes the most severe surge condition. The sudden stopping of a pump creates a rapid down surge immediately downstream of the pump. The magnitude of the down surge is primarily controlled by the polar (rotational) moment of inertia of the pump and motor and its influence on the rate of change of the flow velocity of the fluid. Under certain conditions, the down surge may reach full vacuum (14.7psig), causing the water to vaporize (boil) and create vapor pockets. Subsequently, depending on the pipeline profile, column separation may occur from a full vacuum pressure condition, resulting in the formation of vapor cavities. As time elapses after the pump failure, the forward velocity diminishes, and flow reversal follows. The rejoining of water columns at the location of the vapor cavity may result in the cavities collapsing explosively, thereby generating extremely high, localized pressures. This phenomenon is typically referred to as “waterhammer”. It is difficult to accurately predict the location and magnitude of vapor cavities and resulting “waterhammer” pressures. However, a possible consequence of inadequate design for “waterhammer” pressures can be the collapse of the pipeline from repeated vacuum conditions and/or the failure of pipeline joint systems resulting in significant leakage or bursting of the pipeline from a “waterhammer” pressure spike. In design, MWH does not allow full vacuum pressures to exist along the pipeline.
2.10.5.
Surge Control Methodologies for Pumped Pipeline Systems Surge control devices, generally mechanical devices, mitigate or lessen the impact of an uncontrolled or unplanned hydraulic condition. Because surge control devices are mechanical, the surge control system itself can be susceptible to failure if not properly maintained. Therefore the best way to control adverse hydraulic transient conditions is not through the addition of mechanical surge control devices but through design. If the hydraulic system can be designed to react to uncontrolled and/or unplanned hydraulic conditions without additional mechanical devices and without putting the system at risk, then these design considerations should always be applied. These may include larger or parallel piping systems to reduced flow velocity, or pipeline route and profile selection to limit the static head and potential “waterhammer” effect. Rarely are these types of design solutions practical because of inherent operating or physical requirements or even feasibility of the design solution relative to cost. As a result, mechanical surge control devices are commonly used to mitigate and control adverse hydraulic transient conditions. These surge control devices can be categorized into two groups: one Page | Chapter 2-82
OCT 2011 being a Primary Control device and the other being a Secondary Control device. A primary surge control device immediately begins to influence the system’s hydraulic behavior once positive control is lost, as in the case of an uncontrolled pump shutdown. These primary control devices prevent the hydraulic transient pressures from fully forming or becoming severe. Also, a primary control device provides a positive benefit to all components of the system including pumps, valves, pipelines and other hydraulically connected appurtenances. A secondary surge control device is a reactive device. Generally, these devices respond to already developed severe hydraulic transient pressures and then react to reduce or localize the severe pressure conditions. These secondary surge control devices are very capable of protecting local areas from adverse transient conditions, but individually do not provide a comprehensive surge control for all components of the system (i.e. pumps, valves, pipelines). A description of various Primary and Secondary surge control devices utilized to control surge are briefly described below.
2.10.6.
Primary Control As previously mentioned, power failure at a pump station is the primary cause of surge problems due to a rapid decrease in the flow velocity. Therefore, the primary method of controlling surge caused by pump failure is to control the rate of change of flow at the pump station. The rate of change of flow needs to consist of a slow decrease and eventual stopping of the flow in an orderly fashion. Increase the Rotational Moment of Inertia of the Pump/Motor System. The increase in rotational moment of inertia (WR2) in a pump station for surge control is typically accomplished by the addition of a flywheel. A flywheel is a bladed or spoked wheel rotating mass attached to the rotating assembly of a pump and motor providing additional rotating moment of inertia to the pump assembly. If the pump stops suddenly, the flywheel continues to spin, and water continues to be pushed into the system but with decreasing head. This ensures the water supply does not stop instantaneously and the system pressure drops slowly upon power failure. The amount of water pushed, and the length of time the flywheel spins, is based on the rotating system’s WR2, and therefore on the flywheel’s size and weight. Increasing a system’s WR2 by the addition of a flywheel is an effective method of controlling surge in limited situations, typically when the pipeline is relatively short and the profile is flat.
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Figure 2-50: Vertical Flywheel Sketch
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Figure 2-51: Horizontal Flywheel Sketch
Figure 2-52: Horizontal Internal Motor Flywheel Installation Utilize a Hydropneumatic Pressure Vessel. Hydropneumatic pressure vessels are normally connected to the pump station discharge header, and each pump is normally equipped with a check valve. The upper portion of the pressurized tank is filled with a volume of compressed air, designed to balance the pump head. For very low lift pump stations, the pressurized tank can be replaced by an open tank or by a standpipe. Upon power failure, pump forward rotation stops rapidly, normally in a matter of a few seconds. The sudden cessation of water flow causes the head downstream of the pump station to decrease sharply. As this occurs, flow is supplied by the surge tank to the discharge header, shutting off the check valves to the pump. The flow supplied by the surge tank continues decreasing slowly as the pressurized air in the tank expands. The surge tank provides sufficient pressure to maintain positive pressure throughout the entire length of the pipeline and so no vapor Page | Chapter 2-85
OCT 2011 pockets form in the pipeline. As time progresses following the surge event, the pressure in the surge tank decreases, the forward flow of water decreases, and the water flow eventually reverses direction in relation to the static head in the terminal reservoir. This flow then enters the surge tank, re-compressing the air in the tank. The pressure rises as the water volume in the tank increases. This process repeats itself in cycles until the water’s motion is dampened out to an equilibrium situation due to system friction and energy losses.
Figure 2-53: Horizontal Hydropneumatic Surge Tank
Figure 2-54: Typical Surge Tank Installation
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Figure 2-55: Small Capacity Bladder Type Pressure Vessel
2.10.7.
Secondary Control Depending on the pipeline profile downstream of the pump station, mitigation of surge pressure by primary surge control measures at the pump station may be impractical or inadequate. Under these conditions, secondary control devices can be installed on the pipeline at selected locations. Depending on the situation, secondary control measures can be used alone or to supplement the primary control facilities at the pump station. Commonly employed secondary control devices include (1) combination vacuum relief and air release valves, (2) one-way surge tanks, (3) pressure relief valve, (4) slow closing control or check valves and (5) surge anticipator valves. Vacuum Relief and Air Release Valves. Vacuum relief valves are used to allow air to enter the pipeline whenever the pipeline pressure falls below atmospheric pressure. The entrained air must later be released slowly through a corresponding air release valve when the pipeline regains pressure. Combination air/vacuum valves for transient control shall be designed for air release or is equipped with surge dampening/check mechanisms to prevent damage to the float or seat. A scheduled maintenance and repair program is required for an air valve to retain it’s ‘like new’ level of performance. To facilitate maintenance for critical combination air/vacuum valves required for surge control, a tandem valve should be considered to adequately protect the system while valve service and maintenance is performed. In a system where the air valves and air valve vaults are not properly maintained the air valve may not be perform adequately when required. This may result in severe Page | Chapter 2-87
OCT 2011 vacuum conditions causing damage to elastomeric seals and gaskets used at joints and flanges within the pipeline system. This damage leads to potential leakage and under sustained vacuum condition standing ground water may be drawn into the pipeline creating a contaminated water condition. Also, if an air valve vault is not properly drained and storm water runoff is allowed to flood the vault another potential cross connection may occur when the vacuum valve opens. One-Way Surge Tank. In pipelines operating under pressure, the normal Hydraulic Grade Line (HGL) is often far above the pipeline. Under this condition, it is impractical to install an open standpipe on the pipeline, and a one-way surge tank is often used. A one-way surge tank has a check valve between the tank and the pipeline it is protecting. The water surface elevation in the tank is kept above the pipeline crown elevation but far below the normal HGL. During a surge event, when the HGL in the pipeline at the one-way surge tank location drops below the water surface elevation in the tank, water flows from the tank into the pipeline. This operation provides additional water to the pipeline, preventing water column separation, and thereby reducing the possibility of “waterhammer” due to separated water columns rejoining. Slow Closing Check Valve. Another way to provide surge relief is to require a very slow closing check valve. With this type of check valve the surge pressure is translated back through the pumps which act like a surge dampening device as it slows down and begins to spin backwards. The check valve is then closed before a runaway pump condition is achieved. Surge Anticipator Valve. A surge anticipator valve is installed on a pipeline system to provide relief from high pressures. Instead of operating upon detection of a high pressure, a surge anticipator valve is actuated by detection of a specific occurrence known to cause surge conditions in the pipeline (power failure). Similar to the pressure relief valve, the surge anticipator valve discharges to the atmosphere or a system with a lower HGL than the pipeline. Upon opening, most surge anticipator valves initiate a slow closure to stop the flow of water from the system.
2.10.8.
Hydraulic Design Package The Senior Hydraulic Design Specialist will not have detailed knowledge of each specific project. It is the design engineer’s responsibility to provide all the relevant project data to the Senior Hy-draulic Design Specialist. The following page includes a list of the data requirements necessary to perform a hydraulic transient analysis. It is the design engineer’s responsibility to gather all the data together in a neat and orderly manner.
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Hydraulic Design and Data Package Requirements Data Requirements for System: 1. Provide a description of the system. 1 2. Provide influent flow and/or design flow rationale. What is the range of flow required? 1 3. Provide the hydraulic boundary conditions: water surface elevations or pressures (define range) at pump station wet well and pipeline end.1 Data Requirements for Pipeline: 1. Provide the pipeline design criteria. Include requirements for maximum pressure and maximum velocity and pipeline system curve. 1 2. Provide plan and profiles for the suction and discharge piping. Include the pipeline materials, linings, pressure class, restraint, joint types, pipeline age (if existing), pipeline length. 1 3. Provide a data file which includes the pipeline stationing and pipe invert elevations. Data Requirements for Pump Station: 1. Provide the wet well geometry, including the wet well size and volume. 2. Provide the pump cycle time. 3. Provide the proposed pump station layout, including number of pumps, TDH, preliminary curves, yard piping and meter and valve vaults. 1 4. Provide pump information including pump type, design flow rate, pump and system curves, pump and motor rotational inertia (WR2), do the pumps include non-reverse ratchets? 1 5. Provide information regarding check valves and characteristics of any pump control valves. 1
Data Requirements for Air Valve Design: 1. Provide the client preferred air release valve? 2. Provide client specific air release valve maintenance history or lack thereof. 3. Provide the air valve station data: type of air valves proposed, size of valves, level of redundancy at each station (are there two or one at each station?) Data Requirements for Other: 1. Provide information (drawing and verbal description) of Receiving Structure or Reservoir. This information should also include the free water surfaces at the respective structures. 2. Provide client design criteria or preferences and experience in surge control. 3. Provide project design criteria or preferences. 4. Provide a description of the control strategy (automatic, manual, set points, etc) 5. Provide any pump system operating information that the client may have. 6. Realistic deadline for completion of work and job number. 1 1
Required for Preliminary Analysis
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2.10.9.
Advantages and Disadvantages of Various Surge Mitigation Strategies The following section identifies the advantages and disadvantages of various surge mitigation strategies. As mentioned previously, the Design Engineer shall contact the MWH Hydraulics Specialist for assistance when evaluating different strategies. a. Hydropneumatic Tanks with Distributed Air Valves – This option includes a pressurized tank hydraulically connected to the discharge header. During pump/power failure, a low pressure wave is created downstream of the pumps. The pressurized tank discharges water into the pipeline reducing the severity of the low pressure wave, lessening water column separation and minimizing the reflected high pressure wave.
Advantages: Since there are no moving parts, it reacts instantly to the pressure waves. This strategy is reliable and mitigates both low pressure waves and high pressure waves. Furthermore, it helps with normal operating changes such as startup and shut down and changes in flow condition.
Disadvantages: The pressurized tank includes a compressor to maintain air water surface in the tank. The compressor requires regular maintenance. Furthermore, the tank is connected to the system through an isolation valve. If the valve is accidently closed, the system has no protection or can be mitigated by using a chain and lock around the actuator.
b. Standpipes – A standpipe is a vertical pipe with one end connected to the discharge header, while the other is open to atmosphere. Standpipes are designed to hold a water column extending up to the hydraulic grade line. When the HGL fluctuates during a surge event, the water flows from the standpipe into the pipeline, allowing the HGL to fall and rise, dampening the energy.
Advantages: Standpipes are intrinsically safe and reliable.
Disadvantages: Standpipes could be very tall (~300 to 400 Ft)
c. One-way Surge Tank – These tanks are small, non-pressurized tanks installed at high-points along the pipeline. One-way surge tanks provide a source of water to replace water displaced by low pressure waves or a reduced hydraulic grade line in the pipeline. When a low pressure wave reaches the one-way surge tank or the HGL falls below the water surface level in the tank, a check valve between the tank and the pipeline opens. Water flows from the one-way surge tank into the pipeline. This same check valve also prevents water from flowing back into the surge tank.
Advantages: Provides reliable and effective down surge protection at localized high points.
Disadvantages: Tanks are generally sited in lieu of air vacuum valves. The tanks re-quire a much larger footprint than air valves. The one-way surge tanks only provide protection at the specific location.
d. Pump Flywheel – Flywheels minimize the initial down surge by increasing the pump/motor rotational moment of inertia (WR2). In the event of a power failure, the duration of the pump/motor rundown increases significantly. This strategy is typically used for low static head and high flow rate applications.
Advantages: Flywheels are intrinsically safe and reliable
Disadvantages: Depending on the size of pumps and the WR2 required to mitigate the down surge, the flywheel could be very large. As a result the pump layout and footprint of the building would increase. Furthermore, flywheels are not effective for high static head systems.
e. Pump Flywheel & Hydropneumatic Tank – Combining surge mitigation strategies could also provide advantages. Utilizing a flywheel and a hydropneumatic tank combines the advantages of
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OCT 2011 both strategies. Flywheels attached to the pumps would help to minimize the size of hydropneumatic tanks required to mitigate pressure surges.
f.
Advantages: The combined solution is intrinsically safe and requires a smaller hydropneumatic tank than is only a tank was used.
Disadvantage: Flywheels would be very large, and would require larger pump station footprint.
Surge Anticipator Valve with Distributed Air Valves – A surge anticipator valve at a pumping station opens on general power failure or low pressure to protect pumping system equipment from the reflect upsurge pressures. The distributed air valves provide local pipeline protection from low pressures.
Advantages: A hydropneumatic surge tank is not required.
Disadvantages: The anticipator valves are mechanical devices, and therefore, not fast acting. The response method is reactive to a surge in lieu of preventative (as with a hydropneumatic tank). As a surge wave has been created, the pipeline may still experience full vacuum pressure. The anticipator valves are used to minimize the reflected high pressure wave. Anticipator valves require exact adjustment through a needle valve, and are prone to operator error or mechanical failure. The surge anticipator valve diverts the upsurge to a storage area as a means of dissipating energy. This requires additional storage space in forebays to receive back-flow water while anticipator valves are open.
2.10.10. Final Comments As stated previously, hydraulic surges could have the potential to create a catastrophic failure at the pump station or within the pipeline. This aspect of surge analysis represents a substantial risk to not only the operators and client, but MWH Global. Under no circumstances is the design engineer to design a surge mitigating method without the involvement of the Senior Hydraulic Specialist. No one solution applies to all pump stations. Just because a similar size station has a pump with a flywheel, it does not mean another pump station requires a flywheel.
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2.11.
Deliverables Once the design criteria are identified, the design engineer shall summarize and document the criteria in the form of drawings and calculations. Summarizing and documenting the design criteria serves two purposes. First it provides a benchmark to track future design changes either initiated internally or by the Client. Any future changes to the design criteria must be well documented in the design Change Log. Failure to capture changes prevents MWH from recuperating additional costs required for the rework. The second purpose is to provide a starting point for other disciplines to progress their individual designs. In order to avoid rework, the design engineer shall verify calculations have been peer reviewed prior to submitting calculations to other disciplines. The following is a summary of the minimum design criteria required for internal use (examples of the deliverables are included in Appendix B):
System flow and head information
Fluid type, characteristics and material constituents
Pipe Schedule
Pipe sizing and velocity calculations
Pumping Station System Schematic Diagram
Hydraulic Profile
Piping Preliminary Layout
System-head curve with pump performance curves superimposed (PSET)
System NPSHAVAILABLE calculation and NPSHREQUIRED (supplied by the pump manufacturer.)
Pump selection and data sheet
Wet well sizing calculations
Valve and equipment schedule (including power requirements)
Control Strategy Summary
System flow and head information Define minimum, average and maximum system design flows. Determine static heads and friction losses. Fluid type, characteristics and material constituents Determine type of fluid, temperature, specific gravity and percent solution. Determine material constituents of fluid based from laboratory test results. Use material constituents as basis for material selection of pump component Pipe Schedule The pipe schedule is an MWH standard drawing indicating the piping materials used for each process fluid in the water and waste water industry. The pipe schedule is typically modified on a job by job basis. The design engineer shall identify and select the process fluid designations needed, identify the fluid abbreviation used, determine the acceptable materials for the piping and determine the appropriate pipe testing procedures. This information should be made available, by the design engineer, to other disciplines for consistency when identifying process piping on the mechanical, civil and instrumentation and controls drawings. Pipe Sizing and Velocity Calculations
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OCT 2011 The design engineer shall provide calculations detailing the requirements of the piping upstream and downstream of the pumps. The requirements shall include the pipe size, wall thickness and flow velocity. The pipe sizes and velocities shall comply with MWH guidelines pertaining to minimum and maximum flow velocity. Prepare Schematic Diagram of the Pumping System: The Design engineer shall develop a schematic diagram for each pump train and the entire pump station. This diagram, similar to a flow process diagram, shows the quantity, location and sizes of equipment, fittings and valves, flow meters, back pressure valves and any other inline pressure loss devices. Included on this schematic diagram should be unique numbers corresponding to each valve, fitting, pipe section and miscellaneous pipeline items (i.e. flow meter) to aid the input of these items into the Pumping System Evaluation Tool (PSET) a hydraulic calculation program. Design engineer to refer to the appendix for an example schematic diagram. Hydraulic Profile The design engineer shall prepare a hydraulic profile and establish an approximate Hydraulic Grade Line (HGL) for the system. The hydraulic profile shall include the static elevations of the free water surfaces at the upstream and downstream boundaries of the system. The hydraulic profile shall also show the HGL at pump centerline at suction condition, and the HGL equivalent to the TDH of the pump plus the friction losses at the pump discharge. Refer to a sample HGL drawing located in Appendix B.
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Preliminary Piping Layout The design engineer shall develop a preliminary piping layout. The piping layout shall be a plan and section drawing of the pump station, indicating the equipment, valves and piping arrangement, pressure rating and wall thickness of piping. The layout shall take into consideration the required equipment and piping sizes, adequate clearance surrounding the equipment for maintenance and space requirements for ancillary systems. This piping layout shall utilize available information as it will be used by other disciplines to size the overall structure. System-Head Curve with Pump Performance Curves Superimposed As part of the design criteria documentation, the design engineer shall create a system-head and pump performance curve to evaluate the hydraulic fit of the pump to the system curve. The design engineer shall utilize the Pumping System Evaluation Tool to develop a system-head curve for the project with all known bends, elevations and fitting k factors. The design engineer may also want to consider including the pump performance curves from multiple manufacturers. The curve is to visually verify that the specified operating range, efficiencies and pressures can be met by the selected pumps. NPSH Calculations As mentioned previously, the NPSH margin is critical to maintain stable pump station operation. The design engineer shall formalize the NPSH calculations, and include a copy in the design criteria documentation. The calculations would be referred to if the operating levels for the pump station are ever modified. Furthermore, occasionally the submitted or test NPSH curves do not match the pump manufacturer’s catalogue information. The design engineer should have the NPSH calculations finalized and readily for comparison to the submitted pump manufacturer’s NPSHREQUIRED curve. Pump Selection Data Sheet Summary of equipment information shall be listed in a data sheet. The data sheet shall be distributed to all design discipline. Use the MWH Standard data sheet form. Wet Well Sizing Calculations To finalize the wet well hydraulics, the design engineer shall identify the type of wet well configuration utilized in the design. Based on the design selected, the design engineer shall provide sizing calculations per the Hydraulic Institute Standards or the Flygt design recommendations. Calculations should include spacing between the pumps, baffle walls and straight approach distance. The calculations shall also include retention time at minimum flows, and storage capability during a power outage. Valve and Equipment Schedule The design engineer shall develop an equipment list. This is required as early as the Design Development Phase. The equipment list shall include the tag numbers, location, and type of equipment, design capacity and head, motor horsepower, size of valves, pressure, actuator type and horsepower. Use the MWH Standard Equipment Schedule Form.
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3.
PUMP SELECTION To assist the design engineer in selecting the appropriate pumps for a specific process, the Appendix of this Guide includes Schematic Diagrams indicating the typical pump type used for various applications in the treatment processes. The various pumping applications depicted are based on MWH’s core business in the Water and Wastewater Treatment industries. The schematics focus on the types of pumps commonly used in each process unit in the treatment plants. For example, at the water treatment plant pumps are used for raw water, transfer, distribution, aquifer storage and recovery, injection wells. For the wastewater treatment plants, they are used for raw sewage collection, transfer, and reclaimed water distribution. The schematic diagrams provided in the appendix to identify typical locations and use of each type of pump according to treatment plant type. Following is a list of these flow diagrams. a. Process Flow Diagram C.1 – Conventional Water Treatment Plant b. Process Flow Diagram C.2 – Membrane Water Treatment Plant c. Process Flow Diagram C.3 – Conventional (BNR) with Primary Clarifiers – Wastewater Treatment Plant d. Process Flow Diagram C.4 – Membrane Wastewater Treatment Plant
3.1. General The subject matter of pumps is broad and a thorough review is beyond the scope of this design guide. The guide makes no attempt to cover all aspects and variation of pumps. This section is meant to introduce the design engineer to commonly used pumps and discuss some of the subtle differences between various pump types. For details pertaining to each pump type, the design engineer shall utilize MWH standard pump specifications. These specifications cover such details as preferred materials or construction, testing and inspection requirements and optional pump construction features. This section of the guide is divided into two parts, a general overview of pump nomenclature and a technical summary of specific types. The overview section includes a high level description of the various types of pumps and pump naming strategies. The intent is to familiarize the design engineer with various types of pumps and their unique features. The technical summary section contains a detailed datasheet summarizing the specific design features and recommendations when using a specific pump.
3.2. Horizontal and Vertical Centrifugal Pumps The Hydraulic Institute Standards (HIS) define a centrifugal pump as a kinetic machine that converts mechanical energy into hydraulic energy through centrifugal activity. As fluid enters the pump, it is directed to the center of a rotating impeller. The rotational movement of the impeller creates centrifugal force accelerating the fluid radially outward into the diffuser (volute chamber), from which the fluid exits with higher energy than when it entered. The following section describes pumps from both categories horizontal centrifugal and vertical centrifugal.
3.2.1. Design Nomenclature Classifying pumps into categories is a difficult task. The evolution of pumps has created many custom designs for specific applications. As a result, no one classification strategy can capture all pump types. The following section describes a commonly used naming technique when referring to horizontal and vertical centrifugal pumps. The naming terminology, for the pumps, is based on specific design characteristics or pump configurations. A design engineer should be able to define the key characteristics of a pump based on its descriptive name. The end result is a series of terms, from general to specific, that describe the pump and some of its design features. One way to describe this concept is by using a multiple tiered naming structure. Each tier conveys detailed information about the construction of the pump.
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Figure 3-1: Hydraulic Institute Centrifugal Pump Nomenclature – ANSI/HI 1.1
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Figure 3-2: Hydraulic Institute Rotary Pump Nomenclature – ANSI/HI 3.1-3.5-2000
Figure 3-3: Hydraulic Institute Reciprocating Pump Nomenclature – ANSI/HI 6.1-6.5-2000
3.2.2. Overall Pump Design The first tier is used to describe applicable industry standards that govern the construction of a pump. If no industry standards govern, it is acceptable to leave this tier blank. API Pumps The American Petroleum Institute (API) is a governing body that provides recommendations for equipment that service industrial markets. The guidelines governing pump construction is API 610, which
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is very descriptive with regards to construction, materials and performance. API pumps are not normally used for the water industry. ANSI Pumps The American National Standards Institute (ANSI) is governing body that provides recommendations for equipment that service chemical and less critical industrial markets. The ANSI guidelines are not as descriptive with regards to pump construction, but focus on pump interchangeability. Pumps of the same ANSI class should be dimensionally interchangeable with regards to mounting dimensions, size, and location of suction and discharge nozzles, input shafts, base plates, and foundation bolt holes. If this category of pumps is used in the water industry, it would be more expensive than the conventional pumps and therefore they are not usually specified unless requested by the Owner.
3.2.3. Horizontal versus Vertical Centrifugal The second tier involves the configuration of the shafting. This is the most basic method to categorize pumps as it can be visually determined based on pump and piping arrangements. Horizontal versus vertical refers to the orientation of the shaft. The shaft can either be supported in the horizontal plane (cantilevered or between bearings) or suspended vertically. Typically, stating a pump is a horizontal configuration is acceptable. The design engineer has the option be more specific with regards to configuration. Horizontal pumps can be subdivided based on how the shafting is supported. If the shaft is cantilevered from a bearing housing, with the impeller fixed to the end of the shaft, the pump is called overhung. This arrangement is typically referred to as an end suction arrangement. The suction flange is at the front of the pump, and with a top discharge connection mounted tangentially to the outer diameter of the pump casing. The pump casing or nozzle can be rotated at 45or 90-degree increments to allow for connecting at the side or bottom, if required. A horizontal shaft can also be supported by two bearings, one on each side of the impeller. This type of arrangement is typically called a between bearing pump
3.2.4. Impeller Variations The third tier refers to specific characteristics associated with the impeller. Pump manufacturers have developed a wide variety of impeller types, each serving a unique purpose. Listed below are a few typically impeller variations. Non-clog Non-clog terminology refers to a modified pump impeller and volute design. Internal flow passages of the impeller and volute are widened and streamlined to minimize the potential to trap debris. These pumps are able to pass solids contained in the process liquid through the pump’s impeller flow passages without clogging. These style pumps can be configured to be either horizontal or vertical. Typically used for raw sewage, sludge and other solid bearing fluids. Note, although the terminology used is non-clog, clogging can still occur, especially if the materials are, long stringy ropes or rags, cans, rubber, plastic items, and grease. Radial Flow Radial impellers are common throughout the pump industry. Flow enters the impeller, and is directed radially outward from the shaft axis such as vertical turbine pumps. The hydraulics created by this type of configuration is high head – low flow. Typically used for deep wells, lake intakes, high service treated water and booster pump stations. Mixed Flow Mixed flow impellers, are unique design where the impeller vanes sweep backwards. Flow is directed, not only radially, but axially along the shaft centerline. The hydraulics created by this type of design is medium flow and medium head. Typically used to transfer water from the rivers to canals, flash mixers, filter-to-waste or intermediate pumping stations. Axial Flow
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Axial flow impellers convey flow in the axial direction only such as propeller type pumps. The hydraulics created by this type of configuration is very high flow and low head. Typically used for flood control. Recessed Recessed impellers are impellers whose vanes do not extend into the pump volute or extend only partially into the volute, essentially leaving the volute as an open flow passage. Recessed impeller pumps are well-suited for handling slurries, solids, and stringy materials. The maximum solid size is typically limited by the pump suction opening – any solid that enters the pump passes through. The efficiency of a recessed impeller pump is less than the efficiency of a traditional centrifugal pump operating within the same flow and head parameters. Efficiency losses result from flow recirculation around the impeller passages, and from the fluid rotating around the volute numerous times prior to exiting through the pump discharge. Efficiencies in the 40- to 50-percent range are common for recessed impeller pumps. This type of pump can be mounted in the horizontal or vertical position. These types of pumps are typically used for grit, small raw sewage, raw sludge and digested sludge. Screw Centrifugal A screw centrifugal pump refers to a modification made to the pump impeller. In lieu of a radial impeller, this design utilizes a screw centrifugal impeller. It combines the hydraulic action of a positive displacement screw and single-vane centrifugal impeller. Screw centrifugal pumps are typically used in low NPSH applications that include conveying scum, thickened sludge, digested sludge, digester mixing and digester recirculating pumps. The pump can be operated in reverse rotation, which permits the clearing of clogged suction lines.
3.2.5. Coupling Methods (4th Tier) With each tier, the pump nomenclatures describe further details regarding the pump construction. The 4th tier describes how the pump and motor are coupled or connected to the driver. There are three options: close coupled, separately coupled or magnetic driven Close-coupled Pumps Both horizontal and vertical pumps can also be classified as close-coupled. A close coupled pump is directly mounted to the motor shaft using a NEMA C-face motor. The pump casing is mounted to the motor housing, and the impeller is directly fastened to the end of motor shaft. This configuration provides a smaller pumping unit footprint by eliminating the need for a coupling assembly and a bearing housing. Because of their design and low-capacity limitations, horizontal close coupled end suction pumps are not typically utilized as main process pumps in a pump station. Typical applications of this type of pumps include utility fluid recirculation, sampling, and low-capacity booster service. Separately-coupled Pumps Separately coupled pumps are used when joining two separate pieces of equipment with a coupling. The motor and pump are two individual pieces of equipment, both mounted to a common frame. When assembled, there is a small gap between the drive shaft and the pump shaft for which a coupling is mounted to physically connect the two shafts together. Although this creates a larger footprint, the advantage of this configuration is the motor can be removed for repair without disturbing the pump and/or the motor. Horizontal Magnetic-driven Pumps A horizontal magnetic driven pump as shown in Figure 3-1 utilizes a coaxial magnetic coupling to connect the drive shaft and the pump shaft. A magnetic drive assembly is mounted at the end of the motor shaft, and drives the inner magnet or rotor assembly to the rotating element assembly of the impeller. A non-metallic thin shell or casing in the annular space of the drive and inner magnets completely encapsulates the inner magnet and is attached to the pump casing. This design eliminates the need for a mechanical seal or packing, because the Page | Chapter 3-5
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rotating elements at the liquid end of the pump are separated from its driver end. This type of pump is normally used to convey chemicals and other corrosive materials that are confined inside the fluid end of the pump. Magnetic-driven pumps are considered "seal-less". This can be desirable when pumping corrosive chemicals. Some disadvantages occur with magnetic-driven pumps:
The connection between pump and motor is dependent on the magnetic couple. If the torque developed in the fluid end exceeds the rated magnetic torque, toe couple can be lost especially when pumping viscous fluids
the pump is designed with close clearances – not desirable when handling abrasive solutions
Figure 3-4: Horizontal Magnetic-Driven Pump
3.3. Submersible Pumps - Centrifugal The term submersible pump is used interchangeably to describe both vertical centrifugal and vertical turbine submersible pumps. For clarity, this guide will describe each configuration separately. One will be referred to as Submersible Pumps – Centrifugal and the other will be Submersible Pumps – Turbine. Submersible pumps – turbine is discussed in section 3.4.2. Submersible pumps – centrifugal are typically vertical non-clog close-coupled pumps. The pumps and motors are specially designed for both the pump and motor to be submerged below the water surface. The electrical components are designed to be water tight up to a predetermined distance of 65 feet. For submergence over 65 ft the design engineer shall verify with the manufacturer the required submergence is acceptable for the pump. Maintenance for submersible centrifugal pumps could be a concern for certain Owners, as the pumps are not accessible. The pump and motor are typically submerged, and therefore cannot be inspected while in operation. In these situations the pump and motor would needed to be removed from the wet well for inspection and repair. Submersible pump – centrifugal installations are typically provided with guide rails to allow for removal of the pumps from the exterior of the wet well. Guide rails are typically provided by the manufacturer. This type of pump is typically used for raw sewage and other solids bearing fluids.
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3.4. Vertical Turbine Pumps Vertical turbine pumps originally were developed for the agricultural market. The volute is elongated and the impellers are swept back to maximize the pumping ability while minimizing overall diameter. Originally designed as well pumps, vertical turbine pumps include a surface discharge fitting with motor support, while the pumping unit is suspended from the surface, potentially hundreds of feet below grade. Over the years, other industries realized the benefits of using this style of pump as they have a small foot print, and can easily be customized for various wet well configurations. Vertical turbine pumps are now found in both the municipal and industrial markets. The three main advantages of vertical turbines are multi-stage impellers to suit variations in TDH, the ability to change the pump length to meet the submergence and NPSH requirements and a vertical configuration to minimize the equipment footprint. Pump Staging The impeller and volute (called impeller and bowls) are designed to stack on top of one another. The discharge from the first stage is directed into the eye of the impeller for the second stage. As a result, multiple stages can be stacked one on top of the other to increase the total pump head. The number of stages is customized for each project. Create NPSH The column length for the vertical turbine pump is job specific. The length can be manufactured to fit any installation. The benefit of this feature is that the pump length can be increased there by increasing the submergence above the eye of the impeller. An adjustment in pump length results in a change to the NPSH available for the pump at the required operating levels. Low NPSH 1st Stage In order to minimize the length of the pump or depth of the wet well, pumps requiring low NSPH are advantageous. The industry responded to this need by providing specially designed 1st stage impellers that require less NPSH than a typical impeller. Foot Print One feature commonly overlooked is the advantage gained by reducing the size of the equipment foot print. The motor is vertically mounted on top of the pump. As a result – the foot print for the equipment is relatively small. Couple this with the fact that a vertical turbine pump can be mounted directly above a wet well means the suction piping may no longer be necessary. Other Considerations
Hydraulic down thrust is imparted to the top motor bearing. Always check the maximum thrust load versus rated thrust load by the motor with the pump manufacturer. Specify thrust bearings rated at design head of the pump and not shut-off head. DO NOT oversize thrust bearings. Oversized thrust bearings are partially loaded during normal operation and therefore the bearings are not in full contact with each other and they are subject to noise and overheating. Specify bearing life of 60,000 hrs and not 100,000 hrs.
Drive shafts for long or deep setting vertical turbine pumps are subject to shaft elongation or shaft stretch. If shaft stretch is not carefully estimated by the manufacturer, the impeller wear ring could interfere with the bowl wear ring and damage the pump. For deep well pumps, with above ground mounted driver should be limited to 500 to 750 feet deep. Although there are few known well installation in the world with wells as deep as 1,500 feet using suspended shaft VTP, such as at the West Bank, special design have been adopted by pump manufacturers (EMS Pumps in Palestine and National Pump in Arizona) to accommodate clearances due to shaft stretch. In order to prevent problems associated with shaft stretch or bearing problems due to misaligned well shaft, for deep wells deeper than 500-750 feet, use submersible motor driven vertical turbine pumps as manufactured by Centri-lift or Schlumberger. For large lake intake pumps, the maximum size and Page | Chapter 3-7
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length with successful record of experience is 37 inch diameter bowl by 300 feet long, 3,000 horsepower. Smaller bowl diameter and longer shaft pumps maybe extended to 400 feet. Consult the pump manufacturer.
3.4.1. Impeller Variations Similar to the horizontal and vertical centrifugal pumps, custom impellers were developed for special applications. Vertical turbine pumps typically use Francis-Vane impellers. This type of impeller is a blend between radial and mixed-flow. The water is discharged from the impeller radially, but needs an axial component to guide the water into the next stage. As manufacturer’s developed their product lines, impeller variations were introduced to meet specific application needs. Mixed Flow and Axial Flow (Propellers) are common.
Figure 3-5 Comparison of Pump Impeller Profiles
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Radial Flow The original Francis-Vane design focused primarily on the radial component. Flow enters the impeller, and is directed radially outward from the shaft axis. The hydraulics created by this type of configuration is high head – low flow. Mixed Flow Mixed flow impellers, are unique design where the impeller vanes sweep backwards. Flow is directed, not only radially, but axially along the shaft centerline. The hydraulics created by this type of design is high flow and medium head. Axial Flow (Propeller) As mentioned previously, mixed flow impellers convey flow radially and axially. Axial flow impellers convey flow in the axial direction only. The hydraulics created by this type of configuration is very high flow and low head. Note to designer: Propeller pumps are typically single stage. Although adding stages is possible but limited to two stage, a higher head requirement
3.4.2. Submersible Pumps - Turbine The pumping unit (bowl assembly) of a vertical turbine pump can be used in a fully submersible application. A submersible motor is attached to the base of the bowl assembly and both components are lowered into the well. This type of arrangement is typically used in very deep well applications to avoid problems with down thrust which causes stretching of the pump shaft by the weight of the pump and shaft. The main advantage of using a submersible pump – turbine in lieu of a typical suspended vertical turbine is the pump speed. With the motor coupled directly to the bowl assembly, the pump can be operated at 3600 RPM (nominal). When a pump and line shaft arrangement is used for deep well applications, the pumps are typically limited to 1800 RPM (nominal) due to lateral critical frequency vibration associated with the shafting. Double Suction Double Volute Submersible Pumps The latest advances in deep well pumping have lead to the development of a double suction submersible pump. A German Manufacturer, RITZ Pumps, has developed a unique design originally used for mining dewatering application which incorporates a suction inlet above and below the pump assembly. This variation in design not only allows high flows and long setting, but it utilizes a double suction double volute impeller installed in a vertical position. These impellers are hydraulically thrust balanced, creating minimal thrust to the pump bearings. Less shaft thrust equates to less shaft elongation or stretch. Please refer to the pump summary sheet for more information. This type of pump has been used successfully on a lake intake application beyond the length of vertical turbine pumps with above ground motor, where the shaft stretch is of concern. The only disadvantage over the conventional vertical turbine pump using conventional above ground motor is that the submersible motors has approximately 5 percent less efficiency as the standard motors.
3.4.3. Vertical Turbine Solids Handling (VTSH) This variation of the vertical turbine pump was developed out of the need to convey solids. Vertical turbines have very tight clearances in order to minimize space requirements and improve efficiency. This makes the vertical turbine pump ideal for conveying clean water or chemicals. Fairbanks-Morse used their standard Angle-Flow solids handling impeller and mounted it to a vertical bowl and shaft assembly. The bearing supports were also designed to minimize clogging due to stringy materials. Originally developed for use in the storm water industry, the Vertical Turbine Solids Handling pump was developed with the benefits of a vertical turbine, yet has the solids handling capabilities of a vertical non-clog pump. The VTSH pump is a proprietary design manufactured by Fairbanks Morse Pumps. Although other manufacturers (Patterson, for example, has a Multi-purpose Vertical Turbine Pump) have solids handling pumps, the key features described in this section are not common. The design engineer should be careful Page | Chapter 3-9
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when specifying the VTSH pumps, as some municipalities require two manufacturers capable of supplying each equipment. Being too descriptive regarding the design features of a VTSH pump may prevent other manufacturers from bidding the project. See the pump summary sheet for a detailed list of the product features.
3.5. Positive Displacement Pumps Sections 3.1 to 3.4 discuss centrifugal pumps, where energy is imparted to the fluid through centrifugal forces generated by the rotating impeller. Positive displacement (PD) pumps rely on a different physical process to impart energy into the fluid. Fluid enters the pump, and is trapped in a cavity between moving and stationary elements. The moving element pushes the fluid out through the discharge side of the pump. This process can be thought of as a batch process when it comes to pumping. Energy is not imparted through centrifugal motion, but by direct application of forces to an individual cavity of fluid. With each rotation, only a specific volume is discharged from the pump, regardless of the system pressure. As a result of this feature, positive displacement pump should include a pressure relief valve on the discharge piping arrangement. PD pumps are typically used in the water and wastewater fields for pumping chemical solutions and viscous liquids at relatively small capacities and/or high pressures. Applications include sludge conveyance, either inter-plant, intra-plant or for long distance pumping to a sludge disposal site and chemical conveyance and feed. Positive displacement pumps are usually of the rotary or reciprocating type.
3.5.1. Rotary Pumps Rotary pumps are classified as vane, progressive cavity, flexible membrane (diaphragm) and lobe types, with numerous variations of these classifications. Each type of Rotary Pump isolates an individual pocket of fluid, and pushes it out the pump discharge. Table 3-1 from the Hydraulic Institute describes the various types of rotary Pumps. Table 3-2 lists the advantages and disadvantages of a few of the common types of rotary pumps. For specific details on individual pump construction, see the Pump Summary Sheets.
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Table 3-1: Various Types of Positive Displacement Rotary Pumps Internal Gear. Internal gear pumps (Figure 2) carry fluid between the gear teeth from the inlet to outlet ports. The outer gear (rotor) drives the inner or idler gear on a stationary pin. The gears create voids as they come out of mesh and liquid flows into the cavities. As the gears come back into mesh, the volume is reduced and the liquid is forced out of the discharge port. The crescent prevents liquid from flowing backwards from the outlet to the inlet port. External Gear. External gear pumps (Figure 3) also use gears which come in and out of mesh. As the teeth come out of mesh, liquid flows into the pump and is carried between the teeth and the casing to the discharge side of the pump. The teeth come back into mesh and the liquid is forced out the discharge port. External gear pumps rotate two identical gears against each other. Both gears are on a shaft with bearings on either side of the gears.
Figure 2
Figure 3
Vane. The vanes - blades, buckets, rollers, or slippers - work with a cam to draw fluid into and force it out of the pump chamber. The vanes may be in either the rotor or stator. The vane-in rotor pumps may be made with constant or variable displacement pumping elements. Figure 4 shows a sliding vane pump. Figure 4 Flexible Member. This principle is similar to the Vane principle except the vanes flex rather than slide. The fluid pumping and sealing action depends on the elasticity of the flexible members. The flexible members may be a tube, a vane, or a liner. Figure 5 shows a flexible vane pump. Figure 5 Lobe. Fluid is carried between the rotor teeth and the pumping chamber. The rotor surfaces create continuous sealing. Both gears are driven and are synchronized by timing gears. Rotors include bi-wing, tri-lobe, and multi-lobe configurations. Figure 6 is a tri-lobe pump. Figure 6 Circumferential Piston. Fluid is carried from inlet to outlet in spaces between piston surfaces. Rotors must be timed by separate means, and each rotor may have one or more piston elements. See Figure 7.
Figure 7 Screw. Screw pumps carry fluid in the spaces between the screw threads. The fluid is displaced axially as the screws mesh. Single screw pumps (Figure 8) are commonly called progressive cavity pumps. They have a rotor with external threads and a stator with internal threads. The rotor threads are eccentric to the axis of rotation.
Figure 8
Multiple screw pumps have multiple external screw threads. These pumps may be timed or untimed. Figure 9 shows a three-screw pump.
Figure 9 The above table was obtained from the Hydraulic Institute Pump Type and Nomenclature, 1994
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Table 3-2: Advantages and Disadvantages of Various Rotary Pumps Pump Type Internal Gear
Advantages Only two moving parts Only one stuffing box Non-pulsating discharge Excellent for high-viscosity liquids Constant and even discharge flow regardless of pressure conditions
Disadvantages Usually requires moderate speeds Medium pressure limitations One bearing runs in the product pumped Overhung load on shaft bearing
Operates well in either direction Can be made to operate with one direction of flow with either rotation Low NPSH required Single adjustable end clearance Easy to maintain Flexible design offers application customization External Gear
High speed
Four bushings in liquid area
High pressure
No solids allowed
No overhung bearing loads
Fixed End Clearances
Relatively quiet operation Design accommodates wide variety of materials Rotary Lobe
Pass medium solids
Requires timing gears
No metal-to-metal contact
Requires two seals
Superior Clean-in-Place and Service-in-Place capabilities
Reduced lift with thin liquids
Non-pulsating discharge Vane
Handles thin liquids at relatively higher pressures
Dry running may damage lobes Can have two stuffing boxes
Compensates for wear through vane extension
Complex housing and many parts
Sometimes preferred for solvents, LPG
Not suitable for high pressures
Can run dry for short periods
Not suitable for high viscosity
Can have one seal or stuffing box
Not good with abrasives
Develops good vacuum Table of advantages and disadvantages was obtained from Viking Pumps Progressive Cavity Pumps The most common type of rotary positive displacement pump is the progressive cavity pump. Progressive cavity pumps are characterized by an external-helical rotor turning inside of an internal-helical stator tube. The mating surfaces of the rotor against the stator create a series of cavities along its length. As the rotor turns inside of the stator, these cavities close as adjacent cavities open thereby creating a “progressing” cavity moving axially towards the discharge end of the stator. The fluid being pumped travels within these cavities from the suction side of the pump to its discharge. For more information regarding the progressive cavity pump, see the pump summary sheet. Progressive cavity pumps are typically used to convey primary, thickened, de-watered sludge and polymers. Page | Chapter 3-12
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Note to Design Engineer: Progressive Cavity Pumps require dry running protection or else the stator may be damaged. Inclined Screw “Archimedes Screw Pump” The inclined screw pump is a continuous spiral vane attached to a central shaft, mounted in a trough or pipe. When the screw is rotated, the spiral vane scoop water from the free water surface at the entrance of the pump and discharges it at a higher elevation. It is a continuous propeller pump and flows are axial, with no centrifugal action. The primary advantage of an inclined screw pump is that it is a natural variable flow pump which operates at a constant speed. As the free water surface at the suction rises, the submergence of the inlet increases and the pump is able to scoop more liquid. The Archimedes screw pump is usually large capacity low head, non-clogging and therefore advantageous in raw sewage and wastewater applications. MWH Largest installation is 96-inch diameter rated for 100 mgd each at the Helix Water Treatment plant, CA. For more information on the inclined screw pump, see the pump summary sheet.
3.5.2. Reciprocating Pumps Reciprocating pumps are classified as a positive displacement pump because they also impart energy into a single cavity of fluid. Unlike a rotary pump, which imparts energy through a rotating element, reciprocating pumps impart energy linearly through a piston arrangement. With each stroke, the pump cylinder first fills with fresh liquid and then discharges through a check valve. A constant volume of water is displaced with each stroke, regardless of pressure. As a result, the head capacity curve of a reciprocating pump at constant speed is a straight vertical line. The actual flow rate is only a function of the speed of the pump, not the system pressure. Reciprocating pumps have the capability to generate extremely high pressures. As a result of this characteristic, reciprocating pumps typically require protection to avoid damaging the pump or piping. A pressure relief valve is affixed to the discharge piping of the pump. A situation where this over pressurizing of the discharge piping might occur involves a downstream valve. If for example, a downstream valve is closed while the pump is running; the pressure in the discharge piping rapidly increases. The pressure relief valve will protect the pump and piping by opening and diverting the flow to a drain or storage tank until the pump is turned off. Hydraulic Diaphragm Pumps (JESCO, Milton Roy, Wallace & Tiernan) Diaphragm pumps are reciprocating positive displacement pumps that employ a flexible membrane instead of a piston plunger to displace the pumped liquid. High pressure hydraulic diaphragm pumps have a pressure chamber on one side of a diaphragm and a fluid delivery chamber on the other side of the diaphragm. The pumping forces are generated by a reciprocating piston assembly. The assembly includes a piston, a hydraulic fluid chamber and a pressure regulator which maintains the desired discharge pressure. Note, these types of pumps are self priming and may be run dry without damage.
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3.6. Pump Summary sheets The following subsections discuss the various types of pumps used in water and wastewater treatment plant designs. The pumps are categorized by type (centrifugal, metering, rotary, etc.) and are described in sufficient detail for the design engineer to select the appropriate pump for the application being considered. The pump summary sheets shall be used in conjunction with the MWH Guide Specifications to provide the design engineer a clear understanding of the pumps. A basic description of the pump characteristics is provided in each subsection, including a graphic representation of the pump as well as its typical usage application. The hydraulic (flow rate), head (pressure), and power (horsepower) ranges of typical units are provided. Finally, the application of the pump based on usage in MWH projects is provided in tabular form; the same information is provided graphically in Appendix C. Included Pumps
Horizontal Split Case
Horizontal End Suction (ANSI)
Horizontal Non-Clog
Axial Flow
Vertical In-line
Vertical Sump
Submersible Non-clog
Submersible Chopper Pump
Submersible Propeller
Vertical Turbine
Vertical Turbine – Can or barrel Type
Vertical Turbine – Axial and Mixed Flow
Submersible Deep Well
Progressive Cavity
Archimedes Screw
Reciprocating (Double Diaphragm)
Gear
Double Suction Submersible (RITZ)
Vertical Turbine Solids Handling
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Pump Type:
Horizontal Split-Case (HSC)
H.I. Designation:
BB1 (Between Bearing)
Clean and raw water with limited solids Typical Performance 60 to 16,000 Capacity (GPM): 20 to 750 Head (ft): Application:
Power (HP):
1.5
to
1,500
Guide Specifications:
Horizontal Split Case Pumps 43 22 19 and Large Horizontal Split Case Pumps 43 22 20
Reference Projects:
Prairie Waters Project and Aurora and Olivenhain PS SPECIAL FEATURES Split Casing – The casing is divided into an upper and lower half. The upper half can be removed to allow for maintenance of the internal components without disassembly of the piping Double Suction Impellers – Water enters the impeller from both sides, hydraulically balancing the thrust forces. Reduced thrust forces improve bearing life and reduce maintenance. Double Volute – A horizontal partition in the casing designed to minimize radial forces on the impeller. (not shown) Mechanical Seals – The shaft penetrates the volute in two locations. As a result, two seals (packing or mechanical seals) are required. For clean water applications, pump seals are lubricated using pumped liquid supplied from the top casing. For solids bearing fluids, external flushing water is required.
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1. Pump dimensions vary per manufacturer, design engineer should consult with multiple manufacturers comparing dimensional layouts to ensure pump envelope accounts for all manufacturers’ designs. The variation in dimensions applies to the centerline elevation of the suction and discharge flange connections. Depending on the manufacturer, the suction and discharge flanges for the pump may be at the same elevation or they may be off set. Design engineer should review pump and piping alignment at design and submittal phases. 2. Large Horizontal Split-Case pumps may incorporate a double-suction, double- volute design. A double volute is a horizontal partition within the volute that divides the flow into two geometrically similar regions, both on the suction and discharge side of the impeller. The intent of the double volute design is to reduce the hydraulic forces on the impeller. When pumps incorporate a double volute design, the design engineer shall ensure that flow entering the pump is symmetrical in the vertical direction. For example, and upstream butterfly valve shall be positioned such that the axis of the disc is in the vertical direction. Any flow disruptions due to a partially open valve will cause an uneven flow distribution in the horizontal direction, not the vertical direction. It is recommended that the flow distribution entering both sides of the double suction nozzle shall not exceed 3 percent. 3. Due to the nature of the design, the between bearing pump will require two seals and flush plans. The design engineer shall take this into account when sizing seal flush or cooling water requirements and when identifying spare parts.
REFERENCE PROJECTS Project Narrative – The Prairie Waters Project consists of three conveyance pump stations in series. Each pump station includes an onsite forebay for water storage and flow equalization. The stations consist of pumps are Large Horizontal Split Case, 1250 HP with a maximum pump station capacity of 50 MGD at final build out.
Photograph 3-1: Prairie Waters Project Pump Room
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REFERENCE PROJECTS Olivenhain Pump Station Project Narrative: The Olivenhain PS was designed for 325 CFS pump station with 3 – 2,500 hp horizontal split-case pumps with VFD drives and flow control valves station.
Photograph 3-2: Pump Room - 1
Photograph 3-3: Pump Casing (Lower)
Photograph 3-4: Impeller Dynamic Balance
Photograph 3-5: Factory Acceptance Test
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Horizontal End Suction - ANSI
Pump Type:
(Separately Coupled - Frame Mounted) OH1 (Overhung)
H.I. Designation:
Application:
Clean and raw water with limited solids
Typical Performance Capacity (GPM):
30
to
6,000
Head (ft):
18
to
700
Power (HP):
1
to
400
Guide Specifications:
Horizontal ANSI End Suction Pumps 43 22 03
Reference Projects:
LA County Sanitation
SPECIAL FEATURES Casing – Top centerline discharge for self venting of air. The design also permits removal of pump’s impeller from the casing without disturbing the suction and discharge piping connections or the driver. Impeller – Fully open impeller design. (Enclosed impellers are available from most manufacturers) Seals – Custom engineered seal chambers for various applications. Rigid frame feet – Reduces effect of pipe loads on alignments.
Page | Chapter 3-19
OCT 2011
DESIGN CONSIDERATIONS:
1. Pumps are designed to meet ANSI B73.1, which defines the dimensional requirements for various sizes such that horizontal ANSI end suctions pumps of the same standard dimensional designation from all manufacturers are interchangeable. 2. ANSI Pumps are more expensive than the standard end suction pumps. The advantage of ANSI pumps is that most parts are interchangeable and therefore less stocking of spare parts.
REFERENCE PROJECTS Rialto Plant 5 expansion RAS and WAS Pump Station
Photograph 3-6: Horizontal Pump Installation
Page | Chapter 3-20
OCT 2011
Axial Flow
Pump Type:
(Overhung Impeller Separately Coupled) ---
H.I. Designation:
Application:
High flow applications with clean, abrasive, or corrosive solutions
Typical Performance Capacity (GPM):
800
to
200,000
Head (ft):
5
to
30
Power (HP):
100
to
1000
Guide Specifications:
Axial Flow Pumps 43 22 53
Reference Projects:
Not Available
SPECIAL FEATURES Frame – Horizontally split bearing frame for ease of maintenance. Mounting – Can be base mounted or suspended.
Sleeve – Replaceable shaft sleeve for long life. Impeller – Multiple impeller designs and configurations available.
Page | Chapter 3-21
OCT 2011
DESIGN CONSIDERATIONS: 1. This type of pump is typically used for high flow and low head applications. 2. More sensitive to suction configuration. Provide straight approach of at least 4 times diameter
REFERENCE PROJECTS
No example photo available.
None
Page | Chapter 3-22
OCT 2011
Vertical In-line
Pump Type:
(Overhung Impeller Separately Coupled) OH4
H.I. Designation:
Application:
Clean and raw water with limited solids
Typical Performance Capacity (GPM):
50
to
1,400
Head (ft):
25
to
700
Power (HP):
1.0
to
100
Guide Specifications:
Vertical In-Line Pumps 43 21 39
Reference Projects:
Not Available
SPECIAL FEATURES In-line Arrangement – No field alignment required. Mounting – For use with standard Cface motors (low thrust carrying). Casing – Incorporates a back pullout design for ease of maintenance.
Streamlined Suction – Contoured suction baffle reduces turbulence assuring low NPSH requirements. Coupling – Design available in flexiblycoupled (shown above), close coupled and rigid-coupled.
Page | Chapter 3-23
OCT 2011
DESIGN CONSIDERATIONS:
1. Vertical inline pumps are typically used for hot water circulating services. 2. These pumps are supported by the suction and discharge piping. The design engineer shall account for this extra load when selecting pipe support locations. 3. The main advantage of a vertical inline pump is the small equipment foot print. The main disadvantage is that vertical in-line pumps typically have a lower efficiency than a similar horizontal pump. 4.
A typical characteristic of these pumps is low pump efficiency.
REFERENCE PROJECTS
No example photo available.
No reference project available
Page | Chapter 3-24
OCT 2011
Pump Type:
Vertical Sump (Overhung Impeller Separately Coupled)
H.I. Designation:
Application:
VS4, VS5
Clean and raw water, corrosive or non-corrosive chemical, industrial waste
Typical Performance Capacity (GPM):
20
to
3,180
Head (ft):
10
to
310
Power (HP):
1/3
to
75
Guide Specifications:
Vertical Fiberglass Reinforced Plastic Pumps 43 21 36
Reference Projects:
Not Available
SPECIAL FEATURES Mounting – For use with standard Cface motors (low thrust carrying). Double row thrust bearing – Grease lubricated to carry pump thrust load.
Discharge – Designed to comply with any mounting configuration
Grease lubrication – Designed for lubrication of bearings from the surface.
Shaft – One piece heavy duty shaft. Materials – Available in special materials for chemical handling.
Page | Chapter 3-25
OCT 2011
DESIGN CONSIDERATIONS: 1. Typically this type of pump is used for sump dewatering in an intermittent service 2. Based on MWH experience, the bearing design typically used in this style of pump is not suitable for continuous operation 3. Available in thermoplastic or fiberglass construction suitable for chemical or corrosive service.
REFERENCE PROJECTS
No example photo available.
No reference project available
Page | Chapter 3-26
OCT 2011
Application:
Pump Type:
Submersible Non-Clog
H.I. Designation:
VS3
Clean and raw water with limited solids
Typical Performance Capacity (GPM):
30
to
440,000
Head (ft):
25
to
295
Power (HP):
10
to
5,000
Guide Specifications:
Vertical Non-Clog Pumps 43 21 49
Reference Projects:
-------
SPECIAL FEATURES Water Tight – All electrical connections are designed for submergence. Mechanical Seal – Double mechanical seal with leak detection sensors. Impeller – Non clog impeller construction shown. Adjustable suction fittings – Various suction fittings are possible. Pumps may have a flared intake, or be designed for mounting directly to suction piping.
Page | Chapter 3-27
OCT 2011
DESIGN CONSIDERATIONS: 1. When designing large pumping station using submersible pumps, consult with the Flygt Wet Well Design Guide for Large Submersible Pumps. 2. The standard electrical connections have limitations with regards to submergence. Ensure the specification clearly states the maximum submergence required in order for the electrical components to be designed appropriately. 3. Available for dry pit installation. Make sure that motors are rated for dry pit installation. Some manufacturers provide cooling jackets, while others provide Class H insulation to withstand higher temperature rise for dry pit installation. 4. See requirements for NFPA 820 regarding this type of pump in waste water applications.
OPTIONAL MOUNTING CONFIGURATIONS:
REFERENCE PROJECTS Moss Ave PS, City of Santa Monica, CA The 40-mgd pump station was designed to replace and expand the capacity of an existing pump station located in a congested space near the marina and apartment buildings. Architectural theme, high ground water, construction access, construction sequencing, odor, and noise mitigation compounded the complexity of the project. Designed an underground pump station using 5- 200-hp dry pit submersible pumps with standby generators, and wet wells, all located on a very constrained site.
Photograph 3-7: Typical Dry Pit Submersible Pump Installation
Page | Chapter 3-28
OCT 2011
Application:
Pump Type:
Large Centrifugal Non-Clog
H.I. Designation:
VS3
Clean and raw water with limited solids
Typical Performance Capacity (GPM):
30
to
440,000
Head (ft):
25
to
295
Power (HP):
10
to
5,000
Guide Specifications:
Vertical Non-Clog Pumps 43 21 49
Reference Projects:
-------
SPECIAL FEATURES Bearings – Combinations of single and double row bearings for long life, deep groove and grease lubricated. L10 life of 100,000 hrs. Packing/Stuffing Box – Integrally cast for use with packing or mechanical seals. Impeller – Available in radial flow, nonclog two vanes or bladeless design.
Page | Chapter 3-29
OCT 2011
DESIGN CONSIDERATIONS:
REFERENCE PROJECTS Durham Pump Station Project Narrative: The raw sewer influent pump station with firm capacity to 200 mgd, consisting of four 25-mgd and two 40-mgd pumps for Phase 1, and a total of six 40-mgd, 1,000-hp pumps for Phase 2.
Photograph 3-8: Motor Room
Photograph 3-9: Pump Room
Photograph 3-10: Discharge Piping
Page | Chapter 3-30
OCT 2011
Application:
Pump Type:
Submersible Propeller Pump
H.I. Designation:
-----
Clean and raw water with limited solids (Mixed Liquor Recycle)
Typical Performance Capacity (GPM):
30
to
55,000
Head (ft):
25
to
55
Power (HP):
10
to
800
Guide Specifications:
Axial Flow Pumps 43 21 53
Reference Projects:
-------
SPECIAL FEATURES Cable – Water tight cable entry to protect against moisture. Junction Area – Terminal board for cable connects allowing for fast efficient replacement. Electric Motor – Heavy duty, high efficiency, air filled motor. Bearings – Double and triple row grease bearings. Leak Detector – Float type leakage detector provides early warning of mechanical seal failure. Seals – Cartridge type, duplex mechanical seals. Lining – Replaceable case liner Impeller – Axial flow propeller for high flow low head application.
Page | Chapter 3-31
OCT 2011
DESIGN CONSIDERATIONS: 1. The design engineer shall review the Flygt Design Guide for Submersible Axial Flow Pumps. 2. Typical installation is for flood control system where high flow and low head is required.
REFERENCE PROJECTS
No photos available at this type.
No reference project available
Page | Chapter 3-32
OCT 2011
Vertical Turbine
Pump Type:
(Short Setting – Open Lineshaft) VS1
H.I. Designation:
Application:
Clean and raw water with limited solids
Typical Performance Capacity (GPM):
800
to
60,000
Head (ft):
25
to
3,500
Power (HP):
10
to
3,000
Guide Specifications:
Vertical Turbine Pumps 43 21 15
Reference Projects:
East Baton Rouge Trickling Filter PS
SPECIAL FEATURES Staged Configuration – One pumping unit (impeller and bowl) can be stacked on another unit to increase the pressure at the same flow rate. The number of stages varies depending on the hydraulic conditions required. Frame – Custom designed discharge head for motor support and control of critical frequencies. Coupling – Multiple styles of adjustable couplings are available. Lineshaft – Open or enclosed for process lubricated, fresh water injection or oil lubricated bearings. Column – Column length can be provided at any length to match installation. Impeller – Multiple impeller designs and configurations available.
Page | Chapter 3-33
OCT 2011
DESIGN CONSIDERATIONS: 1. Vertical turbine pumps are very sensitive to hydraulic intake design. Design engineer shall closely follow the requirements of hydraulic institute when designing a vertical turbine pumping installation. 2. The design engineer shall define the minimum column length suitable for specific installation requirements. Typically the column lengths are limited by height clearance issues within the pump station. 3. Upon start up, vertical turbine pumps typically expel a large volume of air as the water rises up the column pipe. Vertical turbine pumps are typically provided with a combination air release-vacuum valve adjacent to the pump discharge flange.
REFERENCE PROJECTS Encina Project
Photograph 3-11: Vertical Turbine Pump Installation
Page | Chapter 3-34
OCT 2011
Application:
Pump Type:
Vertical Turbine – Can/Barrel Type
H.I. Designation:
VS6
Clean and raw water with limited solids
Typical Performance Capacity (GPM):
800
to
60,000
Head (ft):
25
to
3,500
Power (HP):
10
to
3,000
Guide Specifications:
Vertical Turbine Pumps 43 21 15
Reference Projects:
Use Helix PS
SPECIAL FEATURES Staged Configuration – One pumping unit (impeller and bowl) can be stacked on another unit to increase the pressure at the same flow rate. The number of stages varies depending on the hydraulic conditions required. Frame – Custom designed discharge head for motor support and control of critical frequencies. Coupling – Multiple styles of adjustable couplings are available. Lineshaft – Open or enclosed for process lubricated, fresh water injection or oil lubricated bearings. Barrel and Column – Length can be increased to increase NPSHa . Suction flange – Suction flange can be above grade or below grade. Impeller – Multiple impeller designs and configurations available.
Page | Chapter 3-35
OCT 2011
DESIGN CONSIDERATIONS: 1. Design engineer shall determine the minimum hydraulic grade line at the pump suction flange to ensure adequate submergence is available. 2. Large capacity barrel/can pumps require straightening vanes on interior of the barrel. See Hydraulic Institute Intake Design Guides for more information. 3. Refer to MWH exception for the vertical distance from centerline of inlet pipe to bottom of pump bell shall be 4 times D, instead of HIS recommendation of 2 times D. 3. Upon start up, vertical turbine pumps typically expel a large volume of air as the water rises up the column pipe. Vertical turbine pumps are typically provided with a combination air release-vacuum valve adjacent to the pump discharge flange.
REFERENCE PROJECTS Refer to Helix Water District project for the City of Las Coches The pump station was designed for 64 mgd with 5-450 hp vertical turbine pumps mounted inside a barrel.
Photograph 3-12: Pump Room – 1
Photograph 3-13: Building Exterior
Photograph 3-14: Pump Room - 2
Photographs 3-15: Building Exterior Page | Chapter 3-36
OCT 2011
Application:
Pump Type:
Vertical Turbine – Axial and Mixed Flow
H.I. Designation:
VS3
Clean and raw water with limited solids
Typical Performance Capacity (GPM):
30
to
440,000
Head (ft):
25
to
295
Power (HP):
10
to
5,000
Guide Specifications:
Vertical Propeller Pump 43 21 53
Reference Projects:
Clark County Tertiary PS
SPECIAL FEATURES Configuration – Available in above grade or below grade discharge. (Below grade discharge shown in detail.) Coupling – Multiple styles of adjustable couplings are available. Lineshaft – Open or enclosed for process lubricated, fresh water injection or oil lubricated bearings. (enclosed shown) Propeller – Custom designed impeller for high flow applications. Vortex Suppressor – Pump may be provided with option vortex suppression plates.
Page | Chapter 3-37
OCT 2011
DESIGN CONSIDERATIONS: 1. Vertical turbine pumps are very sensitive to hydraulic intake design. Design engineer shall closely follow the requirements of hydraulic institute when designing a vertical turbine pumping installation. 2. Upon start up, vertical turbine pumps typically expel a large volume of air as the water rises up the column pipe. Vertical turbine pumps are typically provided with a combination air release-vacuum valve adjacent to the pump discharge flange.
REFERENCE PROJECTS Baton Rouge Trickling Filter PS Project Narrative: The pump station was designed for 200 mgd with 4-200 hp and 4-600 mgd vertical propeller pumps.
Photograph 3-16: Trickling Filter Pump Station
Page | Chapter 3-38
OCT 2011
Application:
Pump Type:
Submersible Deep Well Pump
H.I. Designation:
-----
Clean and raw water for deep setting well water
Typical Performance Capacity (GPM):
50
to
0,000
Head (ft):
25
to
1,400
Power (HP):
5
to
600
Guide Specifications:
Submersible Deep Well Pumps 43 21 23
Reference Projects:
City of Fountain Valley
SPECIAL FEATURES Mounting – Surface mounting plate can be custom designed for most installations.
Inlet – Stainless steel suction strainer. Coupling – with the motor coupled directly to the pump (i.e. no lineshaft), the motor can operate at high speeds maximizing output. Motor – Specially designed submersible motor Efficient use of space to minimize the diameter of the pump for installation into a well.
Page | Chapter 3-39
OCT 2011
DESIGN CONSIDERATIONS: 1. These pumps are typically used in deep well application where high flow and high discharge pressure are critical. As a result, these pumps are typically operated at 1750 or 3500 RPM. 2. Upon start up, vertical turbine pumps typically expel a large volume of air as the water rises up the column pipe. Submersible deep well pumps are typically provided with a combination air release-vacuum valve at the above grade pump discharge flange.
REFERENCE PROJECTS
No photos available at this type.
Page | Chapter 3-40
OCT 2011
Application:
Pump Type:
Progressive Cavity (Moyno)
H.I. Designation:
VS3
Polymers, slurries, sludge, high viscous solutions
Typical Performance Capacity (GPM):
100
to
4,500
Head (ft):
50
to
3,000
Power (HP):
---
to
-----
Guide Specifications:
Progressing Cavity Pumps 43 22 33
Reference Projects:
----------
SPECIAL FEATURES Ultra Flex – Stator elastomers formulated for specific fluids. Wear Resistant – High capacity, high efficiency, low velocity. Bearings – Tapered roller bearings
Page | Chapter 3-41
OCT 2011
DESIGN CONSIDERATIONS: 1. Progressive cavity pumps have the ability to pump highly viscous fluids and fluids sensitive to shear forces. Because of this, they are commonly used in pumping polymers, sludge, slurries, grease, fluids with high solids content, and chemicals commonly found on water or wastewater treatment processes. 2. Note that for municipal applications, MWH recommends a maximum of 50 psi per stage for light abrasive fluids, 35 psi per stage for medium abrasive fluids (most municipal sludges), and 15 psi per stage for highly abrasive fluids. If the fluid type requires the designer to specify a natural rubber stator, then the applicable maximum pressures per stage shall be 40, 30, and 10 psi, respectively. If the fluid type is polymer, the maximum pressure per stage shall be limited to 50 psi, due to the high shear sensitivity of polymer. If the pump is used in abrasive applications such as sludge, MWH recommends using a minimum of two stages so that as the stator wears down, more lobes would be used to push the fluid. Additionally the maximum speed is kept between 250 to 300 rpm in order to minimize wear. 3. Progressive cavity pumps require run dry protection to prevent stator damage.
REFERENCE PROJECTS No Reference Project
Photograph 3-16: Trickling Filter Pump Station
Page | Chapter 3-42
OCT 2011
Application:
Pump Type:
Archimedes Screw
H.I. Designation:
-----
Raw water, variable flow, with solids
Typical Performance Capacity (GPM):
30
to
---, ---
Head (ft):
25
to
---
Power (HP):
10
to
----
Guide Specifications:
Inclined Screw Pump 43 22 26 and Large Inclined Screw Pump 43 22 27
Reference Projects:
Use Helix WTP
SPECIAL FEATURES Intake – Archimedes Screw Pumps are a variable flow pump. As the water level in the intake rises, more water is scooped into the vanes. Construction – Enclosed or open variations in design are available. Flights – Variable number of flights (vanes). Each additional vane increases the pump capacity.
Page | Chapter 3-43
OCT 2011
DESIGN CONSIDERATIONS: 1. In the past 20 years, screw pumps have become common for sewage applications, due to capital costs considerations and reliability. Screw pumps may be installed in the open on an incline of about 30 degrees to the horizontal, or in a pipe, where the incline is usually about 45 degrees. There are no hydraulic friction or velocity head losses in the open case so the total dynamic head is merely the difference in liquid levels. In an enclosed installation, additional losses due to entrance, and discharge losses must be considered in the design. Screw pumps are mostly used for pumping raw sewage or other waste flows with high solids content and when the total lift does not exceed 10 feet. They are also utilized as a least cost alternative for intake pumping stations from rivers and channels, especially for irrigation applications. The selection of screw pumps and the layout needs to be closely coordinated with manufacturers. Screw pumps can be installed outside, however, for raw sewage applications they are often enclosed or covered. 2. Capacity of the pumps is based on the diameter, number of flights and speed of the pump. 3. Design engineer shall consult the pump manufacturer to determine if external lubrication of the bottom bearing is necessary.
REFERENCE PROJECTS Project Narrative: The pump station was designed for 100 mgd with 2-108-inch diameter archimedes screw pumps to lift water from the sedimatation basins to the ozone contactor.
Photograph 3-18: Typical Pump Installation
Page | Chapter 3-44
OCT 2011
Application:
Pump Type:
Reciprocating Pumps (Double Diaphragm)
H.I. Designation:
---
Chemical solutions or liquids containing minimal solids
Typical Performance Capacity (GPM):
--
to
---
Head (ft):
--
to
---
Power (HP):
--
to
---
Guide Specifications:
Diaphragm Pumps 43 22 59
Reference Projects:
Use Helix WTP
SPECIAL FEATURES Check Valve – Double diaphragm pumps include a series of ball check valves that oscillate depending on which side is operating. Diaphragm – Pressure is transferred to the fluid chamber through the diaphragm. Piston – The piston oscillates back and forth engaging each diaphragm.
Page | Chapter 3-45
OCT 2011
DESIGN CONSIDERATIONS: 1. Applications involving diaphragm pumps may be susceptible to pulsation issues. As a result pulsation dampeners or pressure relief valves may be required. The design engineer shall evaluate the system to determine the appropriate design features.
REFERENCE PROJECTS No Reference Project
Page | Chapter 3-46
OCT 2011
Application:
Pump Type:
Gear Pump
H.I. Designation:
---
Clean and raw water with limited solids
Typical Performance Capacity (GPM):
30
to
600
Head (ft):
25
to
550
Power (HP):
10
to
-----
Guide Specifications:
Gear Pump 43 22 66
Reference Projects:
----------
SPECIAL FEATURES Fluid Cavity – zone in which the fluid is pushed through the pump.
Page | Chapter 3-47
OCT 2011
DESIGN CONSIDERATIONS: 1. No special design considerations other than what is shown on Table 3-1 and 3-2
REFERENCE PROJECTS No project identified at this time.
Photograph 3-18: Typical Pump Installation
Page | Chapter 3-48
OCT 2011
Application:
Pump Type:
Double Suction Submersible (RITZ Pumps – HDM)
H.I. Designation:
VS3
Clean water – deep well applications
Typical Performance Capacity (GPM):
30
to
26,500
Head (ft):
25
to
5,000
Power (HP):
10
to
---
Guide Specifications:
-- -- --
Reference Projects:
Use SNWA
SPECIAL FEATURES Suction Intake – Double suction design reduces the intake velocities, creating more favorable hydraulics. Zero Thrust – The double suction design is utilized to balance the axial forces created by the impellers. Suction Intake – Double suction design reduces the intake velocities, creating more favorable hydraulics. [ This design is a proprietary design by Ritz Pumps ]
Page | Chapter 3-49
OCT 2011
Fluid Path Through Pump
DESIGN CONSIDERATIONS: 1. Used for deep setting Lake Intake PS to 400 ft. Typical use is for mine dewatering system 2. Balanced hydraulic thrust therefore less hydraulic imbalance. 3. Example installation is at IPS-2, SNWA, Las Vegas. 4. The design engineer is cautioned with regards to specifying this type of pump. Currently only one manufacturer can supply a pump with these unique features.
Page | Chapter 3-50
OCT 2011
REFERENCE PROJECTS SNWA IPS-2 Two submersible horizontal split-case pumps with approximate rating of 30 mgd, 3000 hp, 300 ft deep was installed as a test pump I n place of the vertical turbime pumps.
Photograph 3-20: Submersible Pump
Page | Chapter 3-51
OCT 2011
This page left intentionally blank
Page | Chapter 3-52
OCT 2011
Application:
Pump Type:
Vertical Turbine Solids Handling (VTSH)
H.I. Designation:
VS3
Flow with solids and stringy materials
Typical Performance Capacity (GPM):
2,000
to
70,000
Head (ft):
10
to
100
Power (HP):
10
to
-----
Guide Specifications:
-- -- --
Reference Projects:
--------
SPECIAL FEATURES Line shaft – Fully enclosed lineshaft Column – Furnished with an internal vertical splitter plate aligned with the vertical axis of the bowl vane. This feature prevents trash accumulation on the enclosing tube. Bowls – The pump bowls are elongated to provide a smooth transition and avoid clogging. Diffusers – Discharge diffuser has three symmetrically arranged well rounded valves to eliminate radial loads of the impeller. Impellers – Designed with blunt, well rounded leading vanes and thick hydrofoil shape to ensure passage of large solids and stringy material.
Page | Chapter 3-53
OCT 2011
DESIGN CONSIDERATIONS: 1. The design engineer is cautioned about using this pump. Very few manufacturers have a product that can compete as a non-clog vertical turbine. The VTSH is a proprietary design by Fairbanks Morse Pumps. 2. Typical application is in raw sewage and wastewater treatment transfer pumps. 3. Upon start up, vertical turbine pumps typically expel a large volume of air as the water rises up the column pipe. Vertical turbine pumps are typically provided with a combination air release-vacuum valve adjacent to the pump discharge flange.
REFERENCE PROJECTS Project Narrative:
Page | Chapter 3-54
OCT 2011
4.
ANCILLARY SYSTEMS AND COMPONENTS
4.1.
Ancillary Systems This section of the Guide discusses other systems which are present at most pump stations. The design engineer, must be familiar with these systems, and be closely involved in their design. The following section provides a brief overview of the ancillary systems for information purposes only. The design engineer shall work with other company experts when designing these systems. The ancillary systems discussed further are:
Motors
Variable Frequency Drives
Supplementary Water Needs
Odor Control System
Screens and Strainers
Flow Meters
4.1.1. Electrical Electrical systems at a pump station typically includes the power supply, power transformers, motor control centers, electric motors, electric variable speed drives, electrical wires and conduits, luminaries (lighting fixtures), and other associated interfaces with the instrumentation and control systems. The codes, standards and practices are very specific with regards to electrical systems. The design shall only be done by a qualified electrical engineer. Most of the subsequent comments on electrical systems apply to US applications. For designs locations other than the US, the design should be coordinated with technical personnel who are familiar with the applicable local power supplies, codes, standards and practice. POWER SYSTEMS In the US, typical power supplies to the pumping stations are 12/13 kV, 4160 V, 480 V and 240/120 V depending on the size of electrical loads required by the pumping equipment. The range of electrical motor sizes corresponding to line voltage may be as follows: Up to ½ HP
120 to 240 Volts, single phase
½ HP to 500 HP
480 Volts, three phase
600 HP to 2500 HP
4160 Volts, three phase
From time to time, pump stations may lose power during a storm event. When a pump station serves a system where a power failure could result in harm to the public, a sewage spill or fire protection risks for example, the power supply is often required to be connected to a dual grid or standby generator. The purpose of dual grid or stand by generator is to provide a secondary source of power. In the event a local electric grid losses power, an automatic transfer switch will transfer to a second power grid or generator. Sewage pumping stations require individual consideration and the consequences of spills or local flooding require careful evaluation. Depending on how the codes are interpreted, they are often required to have dual feeds, or legally required standby power. This is required to be in compliance with Standards for Class I Reliability Criteria for wastewater treatment plants, as set forth by the U.S. Environmental Protection Agency (EPA), in bulletin EPA-430-99-74-001. This has often been adopted into various state laws, so be sure to check them. Also, the project engineer should investigate historical power outage records and evaluate future potential risks before discussing power supply reliability options or policies with the Client. Page | Chapter 4-1
OCT 2011
MOTOR CONTROL CENTERS All motor starters and disconnect switches are normally installed in the Motor Control Center (MCC). MCC rooms should be located in a separate room away from the source of hazardous gas (such as chlorine fumes and/or sewer gas) or other corrosive environment. Mechanical ventilation equipment should be provided to maintain air circulation. Fresh air inlets to the MCC rooms should be provided with adequate filters with a minimum or 30 percent collection efficiency. The MCC room should be sized with an eye to the future, in addition to providing space for all starters, switchgear and PLC cabinets. Remember there are often needs for security equipment and life safety equipment. Where environmental problems exist, such as the presence of dust, moisture from sea water, or corrosive gas, the MCC room should be designed to have adequate ventilation and air cleaning equipment such as de-humidifiers, filters or carbon adsorbers. Variable frequency drives (VFD) should be housed in an air conditioned room or cabinet with a minimum inlet air filter of 30 percent collection efficiency. For dusty environments, the filtration system should be per VFD manufacturer’s recommendation. Consult our MWH HVAC lead engineer for cooling and ventilation requirements. The MCC circuit breaker should be provided with safety interlocks, as required. In some locations, it is required to have a means of shutting down the system from outdoors. AREA CLASSIFICATION For pumping applications which are integral with a water or wastewater treatment plant, there may be conditions and/or standards that differentiate designs, based on the application, or the proximity to certain plant functions. The location of the pumping equipment relative to the other unit processes will vary from one project to the other; therefore, each area for pumping facilities should be reviewed as early as practical during design to integrate fire prevention and protection or safety recommendations. Locations for pump installations may include wet-pits, dry-pits, digesters, chemical storage facilities, future storage facilities and reservoir roofs. It is not possible to standardize layout and requirements. The project engineer should request applicable code related information from the Fire Department that serves the Client’s site. For the wastewater pump stations in the US, MWH must design pumping stations to meet NFPA 820 (Fire Protection for Wastewater Treatment and Collection Facilities). Fire Protection in the Wastewater Treatment and Collection System facilities has been adopted by most Clients to define area classification and other requirements. Remember, there may be liabilities involved in decisions relating to hazardous ratings. All designs in areas designated as hazardous must be reviewed by the Lead HVAC Engineer and Chief Electrical Engineer or his designated reviewer. During the preliminary design phase, the type of pump and motor is selected based on Client preferences, voltage, strength of the power supply, starting system ( across the line or reduced voltage), location (indoor or outdoor), type of driven equipment ( centrifugal or positive displacement pump, compressor), type of pump (constant speed or variable speed) and site constraints (such as power availability). During conceptual design phase, the detailed design of the pump and motor are determined. The design engineer shall evaluate the pump and motor as one unit, to ensure equipment compatibility. Although the motors are typically handled through the electrical discipline, the design engineer or project engineer should have sufficient knowledge about drivers and appurtenances to understand their function and application. The following sections provide a brief overview of electric and diesel motors for non-electrical engineers. 4.1.1.1. Electric Motors Electric motors are the most common driver for all types and sizes of pumps. They come in an array of styles with specially designed features. There are two types of motors used in the water and wastewater industry namely induction and synchronous motors. The great majority of motors with sizes from fractional to 3,000 hp are induction motors. In larger sizes, (1,000 and larger horsepower) synchronous motors are also used. These motors have a power factor of approximately unity, and are therefore able to help the power factor of the pumping station. They typically cost of a synchronous motor is more than an induction motor and requires special starters. A life cycle analysis is required to justify the use of synchronous motor over induction motors unless otherwise preferred by the Owner. If variable speed
Page | Chapter 4-2
OCT 2011 pumps are required, induction motors are more compatible with VFDs while it is more complicated to match the VFD with synchronous motors. Motors are available in vertical or horizontal position. There is confusion regarding how prime movers such as engines, turbines and especially electric motors are rated. All prime movers are rated based on their output shaft horsepower at a given speed, also called as brake horsepower (bhp). The rating for prime movers is NOT based on the electrical power input. Pumps are rated based on the required bhp measured at the input shaft of the pump. If the pump is directly driven by the motor, the nominal standard bhp rating of the motor shall be equal to or greater than the required non-overloading bhp of the pump without encroaching into the service factor of the motor. The pump bhp is determined using the water or hydraulic horsepower divided by the pump efficiency. The nameplate rating of motor indicates maximum output power, while the input power accounts for motor losses and motor efficiencies. Motor efficiencies, are generally in the 95 to 96 percent efficiency range. x
x 3960
The speed of the pump and motor directly affect the hydraulics of the pump. The design engineer should be familiar with the motor speed terminology, standard synchronous speed, and the effects of electrical frequency (50 Hz versus 60 Hz) on the overall speed. The motor speed is sometimes described in terms of poles. Based on the number of poles and power supply frequency, the design engineer can derive the nominal speed of the motor. The following equation can be used to estimate the motor speed based on the number of poles and frequency of the power supply. The number of poles is only available in even increments.
120 # Based on the above equation, the frequency of the power supply also affects the speed of the motor. This relationship is used when the design engineer is designing a station to be installed in country with 50 Hz power supply. If the manufacturer only supplies pump curves at 60 Hz speed, the design engineer must evaluate the pump with a 50 Hz power supply. Below is a table derived from the motor speed equation. The speeds identified are nominal speeds; motor slip is not shown for clarity. Table 4-1: Standard Synchronous Speed at 60 Hz and 50 Hz # of Poles
60 Hz
50 Hz
2 4 6 8 10 12
3600 RPM 1800 RPM 1200 RPM 900 RPM 720 RPM 600 RPM
3000 RPM 1500 RPM 1000 RPM 750 RPM 600 RPM 500 RPM
Furthermore, when using the motor speed table, maximum running speed of an induction motors are typically 1 to 2 percent below the listed speed due to slippage. For example, the speed of a 4-pole induction motor is approximately 1780 RPM. Synchronous motors, however, their maximum speeds are equal to its synchronous speed because the slip is zero. The speeds are designed to meet the speeds indicated on the above table. Page | Chapter 4-3
OCT 2011
Design Considerations For some installations, electric motors can be supplied with a number of various monitoring sensors. Unless otherwise preferred by the Owner, typically, MWH designs the monitoring system based on the horsepower required by the pump. The following is a list of monitoring criteria guidelines relative to the HP of the electric motor: Less than 50 HP
No temperature monitoring
No vibration monitoring
50 to 90 HP
Provide temperature switches for windings and bearings.
No vibration monitoring unless required by Client.
100 to 350 HP
Provide local resistance temperature detectors (RTDs) on windings and bearings.
No vibration switches or monitoring unless requested by the Client, or other special conditions (vertical motors on wells often get these).
400 to 900 HP
Provide local resistance temperature detectors (RTDs) on windings and bearings.
Pre-alarm switch set at vibration amplitude of 150% of the vibration amplitude at normal operating range.
Shut down switch set at vibration amplitude of 200% of the vibration amplitude at normal operating range.
Vibration switch shall be provided with a time delay to ignore the transient vibration during startup. The timer shall be built into the switch or be part of the PLC.
1000 HP and greater
Provide local and remote temperature detectors (RTDs) on windings and bearings.
Pre-alarm switch set at vibration amplitude of 150% of the vibration amplitude at normal operating range.
Shut down switch set at vibration amplitude of 200% of the vibration amplitude at normal operating range.
Vibration switch shall be provided with a time delay to ignore the transient vibration during start up. The timer shall be either built into the switch or be part of the PLC.
If required by the Client, vibration monitoring equipment should be included in the design instead of vibration switches to have the ability provide alarms and to trend data over time.
4.1.1.2. Engines For some installations, electrical power may not be available or the design criteria may require a backup power in the event of a power failure event. In these situations, diesel engine drivers are a viable option as the prime mover for the pump or to power an onsite generator. As a prime mover, the engine can be coupled to the pump using a gear box, or in the case of vertical turbines, a right angle gear drive. In very few instances, a combination motor and engine gear drive with clutch can be used so that one pump can be driven by either the engine or electric motor. The engine-generator sets may be used to provide Page | Chapter 4-4
OCT 2011 backup electrical power to motor drivers during power outages. Engines can be powered by natural gas, digester gas, LPG, diesel fuel or gasoline. There are a large number of manufacturers of all types and sizes of engines for almost any pumping requirement. Engine drivers are more costly than electric motors for the following reasons:
Initial capital cost
Space requirements
Weight/vibration attenuation require massive foundations
Generally must be located in a secure building
Noise – particularly external exhaust noise
Lubrication requirements
Starting requirements
Engine cooling/building cooling requirements
Increased maintenance costs
Drive lines and gearing required between engine and pump
Fuel storage requirements
Recommended continuous duty shaft speeds for engines, 100-400 HP are usually in the range of 6001200 RPM, a geared increaser may be required to meet pump operating speeds. For small engines, particularly gasoline engines, direct drive applications are common. In such situations, for horizontal pump installations, a simple clutch may be provided. Generally, either parallel or right-angle gear drives are required to match pump speeds. In a vertical pump configuration where an engine is to serve as standby to a motor drive, a combination right-angle drive is installed between the discharge head and the motor. Critical frequency vibrations occur when the speeds of two closely connected rotating units are identical. It is good practice to select units with speed no closer than 25%; i.e. gear ratios 4:3 or 3:4. Senior mechanical engineering staff should be consulted during design of an engine-driven pumping station and should be responsible for detailed design of the engine, pump and appurtenances. Drive Lines and Gears Whether used as a prime mover (directly driving the pump) or as a standby in combination with an electric motor drive, the drive line and gearing between the engine and pump must be carefully designed. The engine must be mounted securely on a concrete pad of a mass of about 4 times the engine’s weight, and then it is normally isolated from the concrete by means of heavy-duty isolators to minimize transfer of vibrations to the concrete base. This allows some small movement of the output shaft which is to be connected to a pump or gear box shaft. It is necessary to provide a flexible coupling or couplings. To insure proper lubrication of the coupling(s), the connecting shaft (drive line) is generally installed at about a 2 to 3 degree offset from exact alignment. A common method for providing this eccentricity is to the use of two U joint-type couplings, such as the Eaton-spicer. On larger units, gear couplings, such as Koppers Fast, have been used with success.
Page | Chapter 4-5
OCT 2011
Figure 4-1: Diesel Engine and Enclosure
4.1.2. Variable Frequency Drives (VFD) Where pump stations are to operate against an infinitely varying flow and head, VFDs are used. By modulating the frequency of the electrical power to the electric motor, the speed of the unit can be adjusted. Variable speed motors should be considered in the following situations:
If pumped-flow must match influent flow from either a limited capacity sump or a sewer collection system, water treatment plant or a water conveyance system.
If the pumped-flow must match varying water demands, such as in a closed distribution system or water/waste water effluent
If the pump station is required to meet a broad operating flow or head range
In some instances such as for the water conveyance pumping system where flow varies with demand but with fore bays and terminal reservoirs, a combination of constant speed pumps two VFDs to trim flows can be used. The only drawback is that the control system would be more complicated as compared to using all variable speed drives. In which case, the capacities of variable speed pumps are normally equal to or 150% greater than the constant speed pumps depending on how steep the system head curve.
4.1.3. Electrical Equipment Space Limitations With regards to the preliminary layout of the pump station, the mechanical design engineer must involve the electrical engineers when estimating the size of the electrical room. The electrical codes indicate minimum clearances in front of and above the electrical cabinets. Failure to follow these code requirements in the preliminary design phase could result in costly rework of the pump station structure. Note that the required working space increases for medium voltage equipment. Two means of egress are typically required for an electrical room. The following is an excerpt from the National Electric Code: (a)
Dedicated Electrical Space – The space equal to the width and depth of the equipment and extending from the floor to a height of 6 ft above the equipment, or to the structural ceiling, whichever is lower, shall be dedicated to the electrical installation. No piping, ducts, leak protection apparatus, or other equipment foreign to the electrical installation shall be located in this zone.
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OCT 2011
Figure 4-2: Figure Indicating Dedicated Space
4.1.4. Supplementary Water Needs (Cooling, Flushing, Injection) When designing pumping systems, the design engineer shall be cognizant of the pump’s supplementary water needs. Not all installations require supplementary water, but where required, the design engineer will need to develop a supplementary water system. The design engineer must verify that potable water is available on site, and coordinate the location of the lines with the civil disciplines. Furthermore, supplementary water systems typically include some type of control panel requiring involvement of electrical and instrumentation disciplines. These panels may include gauges, switches and solenoid valves which need to be included on the P&ID drawings and supplied with power. The need for this type of control panel should be identified early in the project. There are three reasons a pump may need supplementary water: bearing and/or motor cooling, flushing debris from the seal or packing, or lubrication such as an enclosed line shaft on vertical turbine pumps. The design engineer shall coordinate with the pump and motor manufacturer to determine the equipments specific needs, including the flow rate and pressure of the supplementary water. Cooling Water For smaller pumps, cooling water is not typically used. Only in large installations is the dissipation of heat a concern. In these situations, cooling water may be necessary for the mechanical seal or for the electric motor. Due to the high velocities of the seal faces heat buildup is a concern. Mechanical seals may require additional cooling. In these situations, a cooling water line is piped to the seal gland. The seal may also be equipped with a drain line or the cooling water may enter the fluid being pumped. Large totally-enclosed water cooled (TWAC) electric motors may also require cooling water. In these situations, the motor is provided with cooling jackets which surround the enclosure. Water is circulated through these jackets to dissipate heat. The design engineer shall verify that adequate drainage for the cooling water is available. Flushing Debris Supplementary water is typically associated with flushing debris from the pump. The pump’s mechanical seal relies on extremely tight clearances to vaporize fluids across in the seal face. Any debris which enters this area could potentially damage the seal. Potable water at a higher pressure than the stuffing box shall connect to the mechanical seal. The potable water is flushed across the seal face, and into the pumping fluid. When flushing of the mechanical seal is required, the design engineer shall provide a system in accordance with MWH standard detail M-826. Page | Chapter 4-7
OCT 2011
Lubrication Using water for lubricating purposes is typically only an option with vertical turbine pumps. Vertical turbine pumps typically have an open line shaft which relies on the pumping fluid to lubricate the line shaft with rubber fluted bearings. This reliance on the pumping fluid creates two lubrication issues. First, for very deep pumping installations, lubrication of the top bearing will be delayed until the water reaches the bearing. The second issue is the concerns if the pumping fluid may not be acceptable as a lubricant. For deep setting pumping installations, such as deep well pumping, the design engineer will need to design a pre-startup lubrication system (referred to as a pre-lube system). The primary reason for a prestartup lubrication with vertical turbines is to avoid running the bearings dry. For extremely deep pumping installations, the water surface may be a few hundred feet below ground. Since the pump line shaft bearings are lubricated by the pumping fluid, for the first few seconds of operation the upper bearings are running with no lubrication. The pre-lube system is designed to flush the top shaft and bearing with water. The water not only lubricates the top shaft bearings, but trickles down the entire shaft. A few minutes of pre-lube prior to start up will ensure the entire line shaft remains lubricated. Consult pump manufacturer for flushing water requirement. When relying on the pumping fluid for lubrication; there may be situations where the fluid is not suitable for the lubrication needs. The pumping fluid may contain solids or debris that would significantly reduce the life of the bearing. In these types of installations, the line shaft is enclosed in a tube. The interior of the tube is flushed with water while the pump is in operation. This external flushing of the bearings provides adequate lubrication without contact between the pumping fluid and the bearings. When permissible with water quality, food grade oil lubricated bearings can be used.
4.1.5. Odor Control System MWH values the relationships with our clients and their local communities. The pump stations we design typically serve the people in those local communities. Therefore we must be very cognizant of the pump stations impact on the community. The odors created at a wastewater treatment plant or wastewater pump station have the ability to permeate through the community. Wastewater conveyance systems produce odors. These odors can be reduced through design, such as minimizing retention time and avoiding turbulent flow, but cannot be prevented. In the interest of local communities, odor control systems may be installed at wastewater pump stations and treatment plants. Odor control systems are packaged systems designed to remove odor causing gasses from the air. Blowers are installed to provide negative air pressure at the atmosphere above the wet well (or other odor source), drawing foul air into the odor control system. Odor control processes has three methods of capturing odors: absorption, chemical reactions and biological growth. Prepackaged systems can contain one, two or three of these methods. Each of these methods is briefly discussed in the following sections. The design engineer shall work with MWH odor control experts and the odor control system vendors to select and size the appropriate system. 4.1.5.1. Absorption Absorption is process of capturing the odors without the use chemicals or biological growth. Air is generally forced through a media bed of carbon pellets. One of the characteristics of carbon is an ability to absorb odors. Absorption systems are particularly useful for small air flow applications, remote locations or to control specific volatile organic compounds not removed in by the other methods. 4.1.5.2. Chemical Odor Control System Chemical odor control systems, also called chemical scrubbers, use chemicals to initiate a reaction to remove odors from the air stream. A chemical stream irrigates media that provides surface area on which the air flow passes. As foul air passes over the media, odor causing chemicals are removed through a chemical reaction. After the chemical reaction has taken place, the by-products are non-odor causing compounds. NaOH and NaOCl are typically used for the reaction with the H2S (a common odor causing gas).
Page | Chapter 4-8
OCT 2011 In some situations, the odor may be a combination of various odor causing gasses. In these situations, chemical systems can be staged, where each stage introduces a different chemical for targeted odor removal. Additional odor causing gasses, not identified in this Guide, can be removed by the introduction of an array of chemicals. The design engineer shall coordinate with packaged system manufacturers to design the most appropriate system. 4.1.5.3. Biological Odor Control Systems Biological odor control systems do not rely on chemicals to remove odor, but organic growth. The air stream is directed through a porous media bed. The media is kept moist and supplied with nutrients for the biomass (bacteria) growth. Based on the type of odor causing gasses, different bacteria thrive in the environment. Over time, the extent of biological growth reduces the amount of odor causing gasses.
4.1.6. Screens and Strainers The topic of screens include a broad range of suction side barriers varying from mechanically-cleaned fish screens, manually-raked trash racks to fine screens. Strainers, on the other hand, generally refer to a protection devices attached to the suction of a pump that are used to filter out large particles. Screens and strainers should be specified when there is the potential for solids to enter the flow stream. Screens and strainers are not necessary for treated water pumping stations. Pumping stations do not require screens or strainers when drawing water from lakes and off-river storage reservoirs. The reason for not requiring screens and strainers in this application is because seasonal leaf and algae debris can cause maintenance problems more adverse than if screens or strainers are provided. When local existing applications are not available for guidance, provisions for future screening facilities is a safe decision. The following sections describe commonly used screens and strainers: Fish Screens, Trash Racks and Strainers. 4.1.6.1. Fish Screens The design of fish screens is a specialized procedure requiring input from an MWH fish screen expert. Many factors need to be considered, especially permits from state and federal fish and wildlife departments. Protection of fish screens from ice, logs, invasive mussels (Quagga and Zebra) and boats also needs evaluation. As a guide, small slots 3/32 inches wide may be required and mechanical cleaning or air burst is often necessary. Approach velocities may be assumed to be 0.3 ft per sec for initial layouts (based on total screen area and maximum plant design flows). Note, a minimum velocity of 0.25 ft/sec is required to protect against frazil ice. Screen materials are normally type 304 or 316 stainless steel for fresh water intakes. Bronze and other copper alloys are generally utilized for brackish and sea water applications not only they are corrosion resistant but also are repellant to shell fish. The dissimilar metals require protection with sacrificial anodes and insulating flange kits to prevent galvanic. Mechanical cleaning or air bursts are normally necessary for fish screens to prevent seasonal clogging from leaves and debris. 4.1.6.2. Trash Racks Coarse bar screens with 1.5 to 3-inch spacing may be used for protecting pumps from debris. When Tow-Bro sludge scrapers are used for secondary clarifiers, many major sewage authorities do not include trash racks on their standard designs. There is, however, no consistent policy and a clients’ experience is the best guide. Trash racks are more common on large sewage pumping plants. For nonclog sewage pumps, the most dangerous materials are often construction debris such as wooden pipe struts, 2 x 4 wood and other solids inadvertently thrown into manholes. For vertical turbine pumps, stringy debris and rags can clog pumps or wrap around the shaft. 4.1.6.3. Strainers Cylindrical, basket type strainers fabricated from stainless steel wire, may be specified for the suction of pumps. Similar devices may be utilized as vortex suppressors to enhance flow distribution into the pump suction. The design engineer shall consult the Chief Mechanical Engineer if a vortex suppressor is required for the pumping application. Strainer details vary, but the typical wire spacing is in the range of
Page | Chapter 4-9
OCT 2011 ½ to ¾ inches. Strainers may also be mandated on fire pumps (where continuous operation is not anticipated and subsequent accumulation of debris is not a risk.) Strainers are normally not specified due to the risk of clogging (and subsequent damage due to cavitation) which exceeds the risk of damage to the interior of the pump from debris. Except for fire pumps, strainers are not necessary on treated water systems. For raw water applications, strainers are often omitted unless there is a known risk from submerged wood or other debris. Conical wire strainers are sometimes specified for installation on the suction of vertical well pumps. If the well is sealed, there is no need for strainers on encased wells unless it is practiced in the region and/or specifically requested by the client. Furthermore, self-backwashing in-line basket strainers may be required on raw water applications to protect downstream equipment (such as nozzles or spray heads) from clogging. It is good practice to install in-line strainers on the discharge side of the pump in such situations. If a discharge strainer is specified, the size of the mesh in the strainer should be chosen for the particular application; i.e., ¼-inch mesh strainer to protect, say, 3/8-inch orifices downstream. Periodic debris such as clam shells or fish may not be of measurable risk to most pumps but can cause maintenance problems elsewhere in a system.
4.1.7. Flow Meters Measuring pump station capacity using flow meters is common practice in the water and wastewater industry. The instantaneous flow rate can be used in control applications or for monitoring through a SCADA system. There are many types of meters, each based on different operating principles (pressure, sound, electro-magnetic). The design engineer shall work with the client and instrumentation group to determine the appropriate type of flow meter for the specific installation. The design engineer should also discuss the use of flow meters with the Client. If an energy audit is required, accurate flow measurements are necessary. Obtaining accurate flow measurements may require the design criteria to include additional piping and a highly accurate flow meter. Commonly utilized flow meters are listed in the following table. Other devices such as flumes, pitot tubes and tee weirs have applications but they are not generally associated with pumping stations. Table 4-2: Summary of Commonly Used Flow Meters Flow Range
Accuracy
Application
Comments
Venturi & Flow Tubes
10:1
± 1%
Water, Raw and Treated Water
Reliable, accurate
Magnetic Type
25:1
± 1%
Water, Raw and Treated Water, slurries
Accurate, Calibration difficulties
Orifice Plate
4:1
± 2%
Water
Inexpensive, highest pressure drop
Propeller
10:1
± 2%
Calibration difficulties
Multi-path Ultrasonic
25:1
± 1%
Treated Water, screen raw water Water, Raw and Treated Water, slurries
Type
4.1.7.1. Venturi Meters and Flow Tubes Historically, the venturi meter is the most reliable and accepted device for measuring flows. It has the advantage of providing an accurate and repeatable pressure differential which permits for easy field calibration. Two disadvantages of the meter are costs (it is relatively expensive compared to other types of meters) and it is not as reliable for raw sewage applications as “magnetic” and “ultrasonic” flow meters.
Page | Chapter 4-10
OCT 2011 The true venturi flow tube meter is a relatively long (5 pipe diameter) tube with both upstream and “throat” pressure taps. Head losses across the tube are normally less than 12 inches and, in most instances, such losses are not critical. The pressure differential-producing tubes provide similar performance to Venturi tube but are shorter and less expensive. (See Venturi Meter MWH Standard Guide Specification). Venturi type flow tubes are generally utilized for treated water and raw water metering applications. The maximum velocity through such flow tubes is approximately 16 ft/sec based on the nominal inlet diameter. The maximum pressure differential is 300 inches. Water metering applications typically provide 10 pipe diameter of straight pipe flow upstream (and 5 diameters downstream) of the flow tube. 4.1.7.2. Magnetic Flow Meters Magnetic type (or electro-magnetic) meters are non-clogging, full port, low head loss devices suitable for handling fluids with the solids, chemical feed systems and grease found in municipal wastewater. The primary tube is generally flanged tube fabricated from steel and lined with neoprene or Teflon. The maximum allowable velocity through such tubes is 25 ft/sec but most applications are much lower velocities, typically 8 to 12 ft/sec. Consult with manufacturer’s representative for upstream and downstream piping requirements. Typically, the flow meter is installed in between straight pipe sections with minimum length of 5D upstream and 2D downstream. 4.1.7.3. Orifice Plates Orifice plates are highest pressure drop, low-cost pressure differential producing devices. The orifice plates have limited flow measuring range capabilities, typically 4:1, but may be appropriate for measuring flows from a single-unit or two-unit pumping station. They are applicable for such metering applications as sump pumps, lagoon dewatering pumps, side stream flows in water and wastewater plants and other applications where flow confirmation (rather than range of flow) is important. The flow plate is normally a ¼-inch thick stainless steel plate inserted between two standard pipe flanges. The diameter of the orifice should be selected by the manufacturer. Typical maximum flow velocities (based on nominal diameter of adjacent piping) should be in the range of 8 to 12 ft/sec. For the piping configuration, it is important to provide 10 diameters of straight pipe upstream, and 5 diameters downstream. 4.1.7.4. Propeller Meters Propeller meters include full size and a miniature propeller with a drive and gear mechanism. The drive from the propeller to the meter-head, or “register”, can be direct or may include a magnetic drive (which eliminates the need for a drive seal). Propeller meters can be provided with a flanged tube or may be saddle-mounted onto piping. Propeller meters are low-cost and reliable meters. There is need to periodically replace bearings and gears, but maintenance and adjustment requirements are not necessarily greater than static type meters. They are, however, usually utilized for clean water applications, but are also used extensively for non-potable water, free of stringy materials applications, such as measuring irrigation flows. Normally the maximum velocity in appurtenant piping is 10 ft/sec. Straightening vanes are often provided upstream of the propeller. Five diameters of straight pipe are required upstream and only one diameter is necessary downstream. Straightening vanes are often provided within the tube. The meters can be utilized for measuring reverse flows, if 5 diameters of straight piping are provided on each side of the meter. Flows not exceeding 150 percent of nominal capacity may be applied, but high flow rates reduce bearing life. Normal expected period between repairs is 5 years. 4.1.7.5. Ultrasonic Meters The most reliable multi-path ultrasonic flow meters are those meters utilizing varying frequency technology. They are also known as transmissive ultrasonic meters (Doppler ultrasonic flow meters are excluded from the following comments because their accuracy is dependent upon field calibration). Ultrasonic meters are most accurate at high velocities. The normal range of velocity is from 1.0 to 25.0 ft/sec. Higher velocities can be accurately measured but such velocities are seldom incorporated into the design of municipal pumping applications. At normal velocities, say 1.0 to 12 ft/sec, accuracies of +/Page | Chapter 4-11
OCT 2011 1% are achievable. They are suitable for measuring most aqueous liquids ranging from potable water to raw sewage. They are, however, most suitable for clean water applications. They are not suitable for metering sludge or slurries. Head losses associated with ultrasonic meters are negligible. They are particularly applicable to large diameter piping. No special tube is required and for large diameter piping, the cost of equipment may be less than other acceptable meters. Ten diameters of straight pipe upstream of the meter should be provided to ensure accuracy. Some manufactures state downstream conditions do not influence accuracy.
4.2.
Instrumentation and Controls (For Mechanical Group) The design engineer is responsible for the performance of equipment and the overall system. The design engineer must work closely with the instrumentation group to ensure the overall strategy of control is appropriate for the equipment. As a result, the design engineer requires a fundamental understanding of the instrumentation and control methods available. The following section provides a brief overview of the instrumentation and control the design engineer may come across. The control system may be based on either: (a) Programmable Logic Controllers (PLCs), which are solid state devices configured to monitor, control and support display functions, using flat screen display devices or; (b) hard-wired relay logic configured to perform required functions and enclosed in a local control panel (LCP), complete with analog indicators and manual hand stations. Principle monitoring devices include:
Water level sensing equipment
Water pressure sensors
Flow meters
Analyzers (such as pH, residual chlorine and temperature)
Valve positioners and position indicators (Valves and gates)
Gas detection instruments
Switches
Monitoring devices may be local adjacent to the controller or may be remote and transferred to the controller by telephone, radio wave or other modes of transmission.
4.2.1. Pump Control System 4.2.1.1. General This section discusses commonly used station control systems in the water and wastewater industry. Each pumping unit or station must be designed with an appropriate control system to meet requirements of the overall system design. The design engineer must be familiar with the layout and advantages and disadvantages of each system. In many cases, two (or more) independent control concepts can be initiated from monitored information through pre-established programs. 4.2.1.2. Overall Control Strategies Control System Utilizing Water Surface Elevations Sewage pumps are typically controlled by water surface elevations in a wet well. The control system is linked to at least two (one primary and one backup) level sensors. The level sensor could be one of several types, including bubbler, pressure transducer or ultrasonic type. These sensors convey the instantaneous water level at the wet well back to the PLC. As the level rises, the PLC will energize the lead and lag pumps accordingly.
Page | Chapter 4-12
OCT 2011 In addition to operating the pumps, the design engineer should also consider any required alarms hard wired to the pump control panel. Typically, pump stations are provided with a low-low and a high-high float type level switches. At “low-low” level all pumps are turned off and an alarm is initiated. At “highhigh” level a high water alarm is initiated. (Typically all pumps are turned on) These safety back up switches are typically hardwired to operate the pumps without the use of the VFD. For individual pump protection, each pump is provided with a high pressure discharge switch to shutdown the pump in the event of a significant rise in pressure. During accidental closure of the discharge valve, failure of the pump control valve to open, or failure of the check valve to open the unit will pump against a closed valve. As a result, discharge pressure will approach the shut off pressure of the pump. The pressure switch will notify the PLC that the pressure is approaching the shut off head of the pump, and will turn the pump off. These pressure switches are hardwired to protect the pump, without the use of a PLC. If a check valve is used, each check valve should be provided with a micro switch to provide a signal to the pump controller to verify flow after the pump start-up sequence is completed. Variable Speed Pumps in a Control Strategy Variable speed pumps are typically used for the following conditions:
Where more uniform discharge flow to the wastewater treatment plant is required.
Where there is not enough space in the pumping plant to accept installations of multiple smaller constant speed pumps.
Where the wet well volume is limited to satisfy a maximum of number of starts per hour per pump.
Where sewer gas emissions due to rise and fall of the water level in the sewage system to the atmosphere are limited
Where the required speed variation does not exceed 10:1 for variable frequency drives (In practice, it is seldom necessary to operate pumps at speed ranges in excess of 3 to 1.)
Variable speed drive pumps may be controlled as follows.
The following control sequence applies to a station with all pumps capable of variable speed operation:
When the water surface elevation reaches the first set point, the lead pump energizes and ramps to the minimum preset speed. As the flow increases the pump speed increases in proportion to the increase of flow in order to maintain the level in the wet well until the pump has reached its maximum speed.
When the inflow to the wet well exceeds the maximum capacity of the lead pump, the control system energizes the lag pump. The lag pump increases its speed while the lead pump decrease speed to the point where the two pumps share the flow equally, each at the same speed. As the inflow increases, the two pumps increase their speeds together in proportion to the inflow until the pumps have reached their maximum pumping plant design flow in the case of a two pump combination.
In the event a lead or lag pump fails, or the inflow exceeds the capacity of the programmed pumps, the wet well level rises and the standby pump energizes at the same time the failure alarm is activated. The standby pump should be provided with a variable speed drive.
A drop in wet well level equivalent to decrease in pumping plant inflow signals the pumps to reduce speed until the preset speed is reached. The lag pump stops, and the lead pump increases its speed in proportion to the inflow.
Further drop in wet well level signals the lead pump to slow down until the minimum level is reached at which level the lead pump stops. Page | Chapter 4-13
OCT 2011
For pumping plants equipped with more than three variable speed pumps, a similar operating sequence may be followed.
Combination Constant Speed and Variable Speed Drive Pumps The design engineer may consider the use of constant and variable speed units in the same pump station. This type of configuration utilizes the variable speed pump as a jockey pump. Although this system is a potential configuration available to the design engineer, its use is discouraged due to the complexity of the control system. A jockey pump, with variable speed drive, should be sized 150 percent larger than as a lead pump and provide flows in excess of the capacity of the constant speed units. The sequence of operation can be as follows:
When the water surface elevation in the wet well reaches the set point, the lead pump with variable speed drive energizes and increases its speed to a minimum preset speed. As the inflow into the wet well increases, the pump speed increases to match the incoming flow. When the pump speed has reached the maximum speed and the water surface elevation is rising, a constant speed pump energizes and the variable speed drive decreases to minimum speed.
Further increases in the incoming inflow increases the speed of the variable speed pump until the maximum capacity of the pumping equipment is reached. A decrease in wet well inflow reverses the sequence until the lead pump has reached its minimum speed. When the inflow is less than the capacity of the pump at its minimum speed, the lead pump stops after a preset time delay.
4.2.2. Level Sensing Instrumentation The level sensing instrumentation is discussed in the following section. The design engineer shall be aware of any additional equipment necessary to implement one of the following level control systems. 4.2.2.1. Bubbler Level Control System The bubbler tube level control system operates on the principle of measuring the back pressure from the tip of a submerged bubbler tube to the water surface in the wet well and converting this pressure to a physical height. The operating concept involves air bubbling into the wet well. As the surface elevation rises and the depth of liquid increases, the pressure required to force a constant air flow stream out of the open end of the bubbler tube increases. This force, backpressure, is converted to an electrical signal by a linear variable differential pressure transducer and then transferred to a programmable controller. Output from the controller is used to start pumps and adjust the speed of the motor in the case of a VFD or control the magnetic coupling in the case of a magnetic drive. The bubbler level sensor needs an air supply which is usually available in major pumping plants or water and wastewater plants. If plant air is not available, air compressors with automatic alternator are required. Bubbler sensor devices should be utilized when directed by a client or when there is no convenient method of installing a differential pressure transducer. The preferred method of sending level is by use of a flange mounted differential level transducer. 4.2.2.2. Float Level Switches The simplest method of level control is through the use of float switches. As the water surface elevation in the wet well increases, the float is vertically displaced engaging a contact and conveying a signal to the control panel. Float level switches are typically used as hardwire backup for the primary control system. A typical level switch is a float-type switch (specify without mercury). The switch should be designed and manufactured for Class 1 Division 1, Hazardous Conditions 4.2.2.3. Sonic Level Switches The design engineer has the option of using sonic level switches. A sonic level switch emits sound waves that reflect off of the water surface. As the water surface rises, the level sensor can detect a change in the reflected wave. There are space limitations when using an ultrasonic level switch. The Page | Chapter 4-14
OCT 2011 levels switches are installed directly above the water surface. The emitted sound wave propagates out in a cone shape as to moves vertically towards to the water surface. The further down the wave propagates the wider the cone of influence becomes. As a result, sonic level switches cannot be used in small wet wells. The following describes a typical installation: If required, a sonic level sensor can be mounted inside a wet-well, 54-inches (1.375 m) above the high water level. (They can be mounted at a minimum of 12 inches (300 mm) above high water level.) The selection of the level controller should be checked for maximum range and control span. A sonic level sensor has a range of either 25 or 50 ft (7.5 or 15 meters) and should be installed at a minimum 1 foot per 10-foot range (300 mm per 3.0 meters) from the wet-well wall in order not to obscure the sonic wave pattern. The mounting for the sonic level switch should be designed to allow for cleaning of the sensor. Where a sonic device is used, the wet-well should be provided with a mercury type level switch to activate the low-low level pump cutoff and the high-high level alarm. The water surface should also be a concern to the design engineer. To obtain an accurate reading, the sonic wave should reflect off of a clearly defined surface. Wet well debris, turbulence or foam on the water surface has the potential to produce inaccurate results.
4.2.3. Pressure Sensing Instrumentation Pressure sensing upstream and downstream of the pump is critical in evaluating the system for equipment acceptance and long term maintenance. Typical pressure monitoring of the pump includes compound pressure gages/switches on the suction and discharge side of the pump. The pressure gage should be at least 4.5 inches in diameter and positioned on the centerline of the pipe. Furthermore, when seal (flushing) water is required, an interlocked solenoid valve with a flow or pressure switch should be provided (with a delay) to shut down the pump until it is manually restarted. In sewage applications, pressure gages and switches should utilize annular ring seals (not diaphragms) to protect the mechanisms from process contamination. For pumps with constant speed drive, a pressure switch should be provided between the pump and check valve or pump control valve to shut down the pump in the event of failure of the valve to open or accidental closure of any isolation valve located in the pump discharge piping. A microswitch attached to the check valve shaft should be provided in lieu of a pressure switch for VFD driven pumps.
4.2.4. Gas Detectors The use of gas detectors in wet well (and dry pit) areas should be considered and are often required by NFPA 820. Gas sensors should be located with respect to the density of the gas being detected. Methane, which is lighter than air, accumulates towards the ceiling elevations as opposed to hydrogen sulfide which tends to accumulate at lower levels, closer to the floor. Per NFPA 820, gas detectors should be designed to be failsafe and activate warning lights and beacons at ingress and egress points of the monitored space.
4.2.5. Supervisory Control and Data Acquisition (SCADA) System The local control panel at the pump station displays critical information regarding the system. Information pertaining to operating equipment, alarms, open or closed valves and even pressures and flow rates. This critical information is used to monitor and diagnose pump station performance. Many water and wastewater systems link the local pump station control panels to a central control facility. These remote monitoring systems consist of local Remote Terminal Unit (RTU) linked to a computer at the designated central control facility. The central control facility has the ability to display critical information available at the local control panel and a remote location. The remote link gives the operator the ability to remotely monitor all stations in the area. This configuration provides a substantial savings to the authority have jurisdiction as one person could monitor and control several pump stations simultaneously. Information collected through the SCADA system can also be used for preventative maintenance. By comparing historical data, an operator may be able to detect trends in system performance. These Page | Chapter 4-15
OCT 2011 systems typically have the ability to generate multiple reports based on the SCADA information. An application of this feature would be to provide the maintenance team alarms which activated in the past six hours. Each morning a report could be run for all the alarms that activated over night. These daily reports provide the operator additional information that can be used to schedule the maintenance efforts. The previous section discussed SCADA systems that monitored a pump station remotely. The operator has the ability to view the current status of the station. The same process used for receiving signals from the pump station can be used to send signals to the pump station. An operator has the ability to control the pump station remotely. Pumps, valves or any piece of equipment connected to the SCADA system can be designed to activate remotely. The design engineer should also consider the method used to transmit the signal. Client preference is a major factor in determining how the signal should be transmitted. Other factors include the distance the signal needs to travel and the terrain. Methods of transmitting the signal include telephone lines, Ethernet, radio, or satellites. Consult the lead I & C Engineer.
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5.
PUMPING SYSTEM DESIGN This section of the Guide discusses the optimization of pumping systems. No system can be fully developed in one step, it is an iterative process. The design engineer constantly refines the pump selection, piping layout and control strategy. The design engineer is expected to review the pump selection for appropriateness (referred to as the right fit for the system the pump is serving) and evaluate various operating scenarios. The following sections discuss the selected pump’s fit to the system curve and evaluation scenarios.
5.1.
Pump and System Curve Optimization Pump and system head curves can be optimized by establishing the operating range of the pumps as developed by way of the system head curve. The pumps must be selected so that:
The operating points must be near the best efficiency point (BEP). Where possible, the BEP shall be as close as possible to the optimized flow or near the exceedence flow and head point in the system head curve. Exceedence point is defined as the flow in which the pump will operate between 10 to 95 percent at time or operating point of the pump MOST of the time. Refer to Section 2.4.1 for Exceedence Flow Curve.
The pumps’ operating range must be within the Preferred Operating Range (POR)
From the Preliminary Design Phase (PDP) to the design development phase (DDP), the design engineer is expected to perform several iterations with regards to pump and system curves. With each iteration, the fit of the pump curve may change. If the head losses in the system increase, the pump efficiency may decrease and the pump operating point may change. The design engineer must have the ability to analyze the fit of the pump curve to a system. Curve shape When evaluating the fit of a pump curve, the first step is to examine the slope of the curve. An ideal pump curve will always be downward sloping. A flat spot (zero slope) or an upward slope (identified as a dip in the curve) is of concern as this is an unstable operating range. The physics of a centrifugal pump establishes pump head as the independent variable and flow rate as the dependent variable. Meaning the flow rate generated depends on the pump head. In areas where the pump curve is flat or a dip is present, a specific pump head may have a range or multiple possible flow rates. The hydraulics will become unstable and the pump drifts between flow rates. The flat region on the pump curve before the minimum continuous flow region (MCF) is where internal recirculation usually occurs. When the pump is allowed to operate at the flat region of the pump curve, higher vibration is expected due to flow reversal within the water passage of the impeller which would result to cavitation, higher vibration which ultimately reduce bearing and seal life. Conversely if the operating point along the pump curve exceeds the run-out point on the pump curve at high flow low head, not only that the pump will be operating at the lower efficiency but also the NPSHr is the highest and cavitation could also present. For this reason, a pump should not be selected if there is a flat spot or dip in the performance curve; or the operating range is past the run-out point. Design Point The design engineer shall select a pump with the best efficiency at, or close to, the design point. Ideally the design point must be within 25 percent of the best efficiency point. The design engineer shall also verify that multiple pump manufactures are able to meet the required design point. Operating Range The design engineer shall check the maximum and minimum operating points along the pump curve. The system’s maximum and minimum operating points must be within the manufacturer’s recommended pump preferred operating range (POR). The limits of the safe operating range are normally represented on the pump curve by dashed lines near the shut-off head and at the maximum-flow end of the curve. Page | Chapter 5-1
OCT 2011 With regards to multiple manufacturers’ curves, no two manufacturers will have an identical pump performance curve. By specifying certain operating points, such as design points, max flow and min flow, the design criteria may inadvertently exclude certain manufacturers. The design engineer shall review the potential pump curves from various manufacturers to determine what is available. The pump specification should then be modified to include tolerances on the various operating points. The tolerances shall be adjusted to encompass pump curves from various manufacturers. This process will allow multiple manufactures to bid. Non-Overloading Horsepower The design engineer shall review the power requirements for the pump. The required input horsepower to drive the pump is indicated on the pump curve is defined as “brake horsepower” or “shaft horsepower”. All electric motors are rated based on the output shaft horse power or brake horsepower. Electric motors are not rated based on the motor input horsepower or kilowatt. Thus the output horsepower of the motor should be the same as the input horsepower of the pump. The design engineer shall verify the required horsepower is non-overloading throughout the entire pump curve (i.e. power required by the pump does not exceed the nominal rated horsepower of the motor). For mixed flow pumps, the maximum non-overloading horsepower is typically at shut off head. This creates a decision regarding sizing of the electric motors. Covering the entire pump curve may lead to over sizing of the motor. That being said, the shut off head may not be an operating point the pump will ever operate. Unless otherwise stated the pump will never operate near shut off head in which case the motor horsepower can be determine equal to the non-overloading horsepower within the operating range. For variable speed pumping applications, the non-overloading requirement can be limited to the operating range, provided that the pump will never operate beyond this specified range. For pumps driven by VFDs, the motor horsepower shall be determined as follows: Example: Calculate the non-overloading or the maximum brake horsepower of the motor (shaft horsepower) throughout the pump curve. Example maximum bhp = 290 hp. Multiply the brake horsepower by 110% to provide safety factor for any harmonic imparted by the VFD to the motor, which can cause the motor to operate at a higher temperature. Example 290 x 1.10 = 319 bhp. Use the next standard motor size of 350 bhp. Always remember that the motor rated horsepower is based on how much the motor can deliver in terms of brake horsepower. System Curve Preparation refer to Figure 4-3 1. The vertical axis of the graph represents head in feet of water. The horizontal axis represents capacity in mgd or gpm. 2. Designate the maximum static head at point “A” at zero flow. 3. Designate the minimum static head at point “B”. 4. Designate the maximum TDH, point “C” at maximum capacity “D”. Designate the intersection of point “C” and “D” as design point “E”. 5. Select the pump which has the best efficiency point (BEP) near the design point. If the optimized flow and head is other than the design point, select pumps so that when they operate at the optimized flow and head, the BEP should be as close as possible to the optimized flow and head point. For this example, the optimized flow and head is at 700 gpm. 6. Select three pumps so that when all three pumps operate at the same time, they can deliver and meet the design point total pump station capacity of 1,700 gpm @ 130 ft TDH. Make sure that the pumps operate within their POR. 7. Check if only one pump is operating, the operating point is not exceeding the maximum POR or within the run-out point in the pump curve “F”) 8. Plot the performance curve of one pump. Curve “G”. 9. Plot the performance curve for two pumps operating. Curve “H”. Page | Chapter 5-2
OCT 2011 10. Plot the system head curve for three pumps operating. Curve “I”. 11. The design capacity of each pump will be approximately the point where a selected pump curve intersects the design head. 12. Make a tentative pump selection from manufacturer’s curves and superimpose the cumulative pump performance curves on the system head curve as indicated in Figure 4-3. Note the maximum range of head that could possibly be imposed on any pump when running alone or if all pumps were operating. 13. Ensure that the selected pumps can operate over the range of head conditions that are possible. Check NPSH, energy requirements and thrust requirements over the range of head for each type of pump included in the accumulative curves. 14. It is possible to make a detailed investigation of several manufacturers’ curves and specify one or two performance points in addition to the design capacity. For complex application, attach a copy of the pump and system head curve at the end of the specifications. Such an analysis is not necessary during preliminary design and usually it is adequate to specify only the following data. a. Design capacity and design head (design point) b. Minimum pump efficiency at design point c. Maximum shut off head d. Range of heads over which pump may operate e. Maximum required power input at any point within operating range 15. Figure 4-4 shows a typical hydraulic profile of a pump station lifting one from one reservoir and discharging into another. The profile could be applied to sewage applications also. It is important to note that the design head of the pumping units must exceed the mean static lift and should also be designed to exceed the maximum possible total dynamic head Figure 4-3: Typical System Head-Capacity Schematic
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Figure 4-3: Typical System Head-Capacity Schematic
Number of Pumps Several factors influence the appropriate number of pumping units. There are applications where only one unit is necessary (such as a standby fire pump) but in general, two units (one in service and one standby unit) is the minimum number of units that should be provided for municipal water, wastewater and storm water applications. On the other hand, there may be circumstances where ten or more units may be warranted.
5.2.
Multiple Speed Curves For variable speed driven pumps, locate the minimum operating point (intersection of the minimum flow and head) at minimum speed. By using the Affinity Laws (refer to Cameron Hydraulics Handbook), calculate and plot the pump curve at low speed to intersect the minimum operating point on the system head curve. Verify that the envelope bounded by the pump curve at maximum speed and minimum speed will “cover” the entire system head curve. Check to make sure that the pump operating points will not cross unstable areas of the pump curve.
5.2.1. Pump Affinity Laws When optimizing a pump station, the design engineer may need to manipulate the pump performance curves. The reason for the manipulation is typically to identify secondary operating points through speed changing or adjusting the trim of the impeller. Both of these processes affect the performance curves by changing the flow and head by a specific ratio in a predictable manner. The affinity laws of centrifugal pumps predict the effect of changes in pump speed and/or impeller diameter on the pump flow rate, head (pressure), or the power consumption. In the following equations the subscript "1" indicates the initial configuration of the pump, whereas the subscript "2" indicates the final configuration. Any appropriate units may be used as long as they are used consistently within an equation.
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Flow Rate The change in flow rate of a centrifugal pump can be expressed as:
Where q = flow rate n = pump speed d = impeller diameter Head The change in head of a centrifugal pump can be expressed as:
Where h = head Power The change in power consumption of a centrifugal pump can be expressed as:
Where P = power If the impeller diameter is constant the affinity laws become simply:
And if the pump speed remains constant the affinity laws become:
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5.2.2. Pump and System Curve Presentation The presentation of the pump and system curve will primarily be dictated by the output module of the Pumping System Evaluation Tool (PSET). The following is a summary of the type of information to be indicated on the pump and system performance curves. These requirements may be modified depending on the specific requirements of the project. In general, the intent of the graph is to visually describe the operating range of the pump station and show that the selected pump can meet the desired range. In order to accomplish this, the graph must include information on the pump station design, such as operating ranges, and specific pump information such as efficiency. The following is a brief list of the typical information included on a pump and system curve.
Envelope of operation defined by the minimum and maximum system curve
Minimum and maximum flow required for the pump station
Normal operating range for the pump station
Pump performance curve at reduced speed to meet minimum flow requirement
Multiple pump performance curves (i.e. one pump operating, two pumps operating, etc.)
The pump curves must indicate all points between minimum and maximum flow can be achieved
The design engineer shall also indicate the BEP of the pump(s) throughout the entire operating range. The intent of indicating the BEP is to determine when new pumps should be energized to maximize overall efficiency
Figure 5-1: Example System Head Curve The design engineer shall create a summary sheet or graphic comparing the pump performance characteristics of multiple manufacturers. The intent is to develop tolerances between the minimum and maximum operating points to ensue multiple vendors can participate in the bidding process. The pumps need to be evaluated for tolerances with respect to head, power and efficiency at minimum, maximum and the design point. The graphic also allows the reviewer to verify the overall power requirements and maximum shut off head that should be indicated in the specifications. The following graphic is an example of the type of graphic that should be created by the design engineer.
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Figure 5-2: Example System Head Curve
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6.
SPECIFICATION DEVELOPMENT
6.1.
General Considerations The technical and design calculations only represent half of the design engineer’s responsibilities. Not only must the design be technically sound, but the design engineer must develop the equipment specifications required for the construction Contract Documents. The following sections describe the MWH approach to specification development.
6.2.
MWH Guide Specifications The specifications contain technical definitions, detailed equipment descriptions, quality and performance requirements. The MWH format is organized into three parts of related information. “PART I – GENERAL” covers administrative and procedural requirements. “PART 2 – PRODUCTS” defines the quality and performance requirements of materials and equipment which are incorporated into the WORK. In public works contracts, you must specify at least two manufacturers or equal. When specifying multiple manufacturers, specify the minimum efficiency, highest speed and highest required horsepower among the selected top best three manufacturers so that any of the three manufacturers would be acceptable. Procedures which are carried out at the point of manufacturer, such as factory tests, are included in PART 2. “PART 3 – EXECUTION” describes preparatory, installation and other required site activities. The guide specification provides a minimum requirement on the installation, testing and start-up. If additional requirement is needed, specify it under PART 3 – EXECUTION. The design engineer must be familiar with the philosophy of the specifications. The General Conditions state the CONTRACTOR, not the ENGINEER, is solely responsible for the means, methods, techniques, sequences and procedures of construction. The specifications must give the CONTRACTOR freedom to determine the means, methods and decisions as long as quality is not diminished. “PART 3 – EXECUTION” requirements should refer to product manufacturer’s written installation instructions or industry standards without restating them. Any deviations or additions to manufacturer’s instructions should be clearly identified as such.
6.2.1. Relationship to Drawings The drawings show the form and shape of the required facility with locations, sizes, and dimensions of materials and equipment. The specifications should supplement information presented on the drawings, not restate it. The drawings should refer to products by generic names described in the specifications and not contain trade names, manufacturer names, or excessive text information. Drawings and specifications should complement each other without gaps or overlaps, but in case of conflicts or discrepancies, in most public works contracts, the specifications take precedence.
6.2.2. Salient Features Salient features are qualities of a product which are project requirements and which are not common to all competing products. Salient features are the only criteria upon which judgments of product equality can be made. To illustrate the salient features concept, suppose a project has a small floor drain in a room where caustic liquid might spill. A floor drain grating is needed which will not suffer chemical attack or be slippery when wet. Suppose gratings of the needed size come in both cast iron for normal areas and high silicon content cast iron for chemical areas and come in flat and pebbly surfaces. All gratings are strong enough for foot traffic, and all gratings have adequate openings. The grating specification requires high silicon content cast iron with a pebbly surface (the salient features) and does not mention structural strength of the size of openings. The latter two features are not salient because they are common to all competing products. Both are made project requirements by including the specifications and example of quality, say Josam Model 2202. Page | Chapter 6-1
OCT 2011 In shop drawing review, the ENGINEER compares the proposed grating to Josam Model 2202 for structural strength and openings and checks the proposed grating for high silicon content cast iron and pebbly surface. If the proposed grating meets these four criteria, the ENGINEER must approve it.
6.2.3. Descriptive vs. Performance Specifications Technical specifications rely on three approaches to specifying material and equipment items.
Purely descriptive
Purely performance
Hybrid of the two (descriptive and performance based)
A purely descriptive specification describes “hard” salient features: size, shape, color, thickness, surface finish, material composition, rotating speed, required components, etc. Such an approach is appropriate where function and quality are completely controlled by “hard” features and all suppliers or manufacturers offer acceptable quality. A purely performance specification describes only the “soft” function features: parameters such as resistance to compressive force, capacity, efficiency, response time, capability, etc. The purely performance approach is appropriate where the “hard” features make little difference, the “soft” features can be quantified, and all suppliers on manufacturers can meet the specification with acceptable quality. Few “pure” approach specifications are written because the appropriateness criteria are rarely satisfied. Hybrids of the “pure” approaches are used to control quality in a market where product qualities and manufacturer capabilities vary widely. However, the design engineer must be careful to include parameters which do not cause conflicts between the descriptive and performance-based salient features. For example, a specification containing both materials of construction and wear hardness criteria may contain conflicts.
6.2.4. Named Manufacturers Product specifications include manufacturer’s names (and occasionally model numbers) to set the type, the function, and the product quality. This is equivalent to setting the non-salient requirements (the characteristics which are common to competing products where acceptable to the ENGINEER). The design engineer must be aware that he or she cannot enforce any attempt to obtain unique (salient) features or performance by naming a manufacturer’s product. The design engineer must clearly set forth the salient requirements of the material or equipment product in the specification. It is wise to have newly drafted project specifications of major products reviewed by the prospective named manufacturers at early stages of the development of the Contract Documents. The prospective manufacturers should be requested to review and comment on the draft specification as a condition of being specified as a “named manufacturer.” This approach has the following benefits:
Assures the named manufacturers are capable of furnishing products conforming to the requirement specified.
Avoids subsequent disputes regarding the specified requirements not being feasible or attainable
Identifies additional design needs to equipment features necessary for proper installation, operation and maintenance early in the project with sufficient time to accommodate any design modifications.
In addition, to assist the design effort, early manufacturer-review of draft specifications can be utilized to acquire related design information such as dimensions, weights, support utilities, auxiliary equipment access requirements, and electrical service and control requirements.
Be alert, some manufacturer representative will try to offer inferior product or performance to gain advantage over their competition. When this situation occurs, the Design Engineer must use his own judgment which option to consider to meet performance, reliability, longevity and reasonably economical to your Client.
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6.2.5. Specification Issues Unit Responsibility The components of a pumping system (driver, motor and pump) must work together in close harmony for the system to perform efficiently over a long useful life. MWH specifies in the pump sections that the pump manufacturer is to select the motor (within certain limitations imposed by motor and drive sections of the specification) and be responsible for the component system performance. On occasion, with engine-driven pumps we require the manufacturers of the driver to be responsible for the overall pumping equipment. Cross reference between sections Certain technical requirements are common to the equipment specified in separate sections, such as pumps, valves and instrumentation. To avoid repetition in specifying the same requirements in many sections, the common requirements have been consolidated into “parent” sections for incorporation by cross reference. For example, a “parent” section, Section 43 10 50 - Pumps, General defines factory testing, manufacturer’s inspection and training services, and field testing. A “child” section, such as Section 43 21 15 – Vertical Turbine Pumps, places the tests and manufacturer’s services into the scope of the CONTRACTOR’s responsibilities. The MWH Master Guide Specifications are structured into certain “parent-child” families, and contracts in which only one child section appears must include the corresponding parent section also. Proprietary Specifications Proprietary specifications which only one manufacturer can satisfy should be used only with extreme caution with Client’s approval. Most municipalities are bound by State Law, City Charter or their own funding agency procurement regulations which prohibit single-source procurement unless certain steps are taken to obtain approval from higher authority. The ENGINEEER is often caught between the prohibition on one side and the desire on the other side for only a certain product which has ease of maintenance, excellent performance record, long service life, or other desirable characteristics. Unfortunately, manufacturers of competing lower cost products may disrupt the bid and award process, embarrassing the ENGINEER and client staff and delaying the project. The MWH Master Guide Specifications allow price competition between at least two products in almost all cases. A note to Specified warns of proprietary language when a single manufacturer’s product is specified. When the design engineer faces a proprietary situation, he or she should first determine what alternate approval procedures may be available and then discuss the situations with the client. The client must understand the situation and must decide how to proceed. The client must make an informed decision, not the design engineer.
6.2.6. Part I: General Requirements The design engineer may be tempted to pay little attention to this section during the design phase. Clearly defining the contractor responsibilities does not seem as critical. This section is very important during construction and should not be taken lightly. It clearly defines the contractor’s responsibility with regards to performing the work and providing thorough documentation. This documentation is generally submitted to the design engineer for approval, therefore the engineer should have a clear understanding of the type and scope of documentation that will be received. The contractor’s responsibility with regards to submittals is clearly defined. This includes what submittals are to be provided and the technical scope of each submittal. Typical submittals included (this list may vary depending on the equipment specification):
Shop drawings
Materials Certificates
Testing procedures Page | Chapter 6-3
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Torsional or Vibration Analysis
Delivery and storage requirements
Scope of O&M Manuals
Spare Parts Lists
Installation and start up certificates
6.2.7. Part 2: Products The technical information regarding a product or piece of equipment is described in detail in Part 2: Products. This section describes both the performance aspects of the equipment and the salient features. Specifications can present information in different ways depending on the specific attributes of a product. Information is typically presented in table form or narrative paragraphs. As equipment specifications are distributed to specific manufacturers, the design engineer should include all relevant information that may be required to properly select and size the equipment. In some cases, with pumps, it may be beneficial to paste a pump system curve into the specification. The design engineer should always review the notes to specifier located in the guide specifications. These notes draw attention to special features, various options and additional details. They are meant to aid the design engineer in developing a specification that is technically sound and minimizes issues during construction.
6.2.8. Part 3: Execution As the construction of a pump station nears completion, the equipment needs to be installed and field tested to ensure proper operation. In this type of situation, responsibility of the Contractor, Engineer and Client may overlap. To avoid confusion, the intent of Part 3 is to clearly define the responsibility of each party involved. This section details the manufacturer’s, contractor’s, engineer’s and client’s responsibility for during installation and start up. The scope of this section typically includes:
Installation assistance
Field testing for equipment acceptance
Start-up assistance
Training the operators
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7.
DISCIPLINE COORDINATION The final design of a pump station represents the contributions from multiple disciplines. Each discipline’s contribution must not only be functional, but must interface with all other disciplines. As a result, no discipline can work in isolation. Coordination between disciplines throughout the design process is essential in developing a high quality product. The design engineer must actively engage in inter-discipline coordination. The following provides a brief discussion of the coordination points between the mechanical design engineer, and other disciplines. The following is not a complete list of coordination points, but is a starting point to initiate further discussions.
7.1.
Instrumentation and Controls The P&IDs represent a graphical summary of the design of the station and the method in which it is controlled. As the design progresses subtle changes in the mechanical drawing might not be picked up in the P&IDs. These drawings must be checked for consistency with the mechanical drawings. The following identifies a brief list of coordination points between I&C and mechanical.
7.2.
Check P&IDs for physical agreement with mechanical layout for piping, piping sizes and any materials or process call outs.
Verify all valves in mechanical drawings are also shown in the P&IDs including drain valves and air release valves. The design engineer shall verify the size and tag numbers associated with each valve.
Verify control strategy for the equipment is consistent with mechanical approach.
Verify monitoring instrumentation associated with the equipment are shown on the P&IDs (for vibration monitor or temperature monitoring).
Safety showers
Electrical During the progression of the design, it is possible the mechanical equipment may change. The new mechanical equipment may have a different requirement with regards to power. The design engineer shall verify that the power requirements of each piece of equipment agree with the power supply indicated in the electrical drawings. The following identifies a brief list of coordination points between electrical and mechanical.
Verify equipment voltage requirements and RPM requirements for the pumps
Verify equipment power and amperage
Verify any motor references in the equipment specifications are in agreement with the electrical specifications.
Verify electrical has accounted for any piping that requires heat tracing.
Verify electrical has provided power connections to solenoid valves, temperature and vibrations switches.
Electrical cable routing.
Electric unit heaters.
Wiring for safety shower alarms.
Lighting requirements
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7.3.
Structural The design engineer must also coordinate with the structural group regarding the pump station design. The mechanical design engineer is primarily concerned with the interface points between the equipment and the building structure. The following identifies a brief list of coordination points between structural and mechanical.
7.4.
Confirm clearances between the bridge cranes and supporting structures
Verify wall penetrations do not occur at wall joints
If wall penetrations are close to corners or floors, verify adequate clearance for a wall sleeve or link seal.
Verify equipment pad dimensions comply with mechanical equipment cut sheets
When dealing with vertical turbines, confirm the actual weight of the equipment was provided to the structural group.
Pipe supports and piping loads.
Civil As can be expected, there may be overlap between the civil and mechanical design engineer’s scope of work. The following identifies a brief list of coordination points between civil and mechanical
7.5.
Verify pipe invert elevations and sizes at interface between mechanical and civil drawings.
Verify if double couplings are provided to take up differential settlement between the building and yard piping.
Verify any yard piping upstream or downstream of the pump agree with hydraulic calculations performed previously.
Verify the 100 year flood plain elevation. Use the Federal Emergency Management Agency (FEMA) guidelines.
HVAC and Plumbing The design engineer must also coordinate with the HVAC group regarding the pump station design. The mechanical design engineer is primarily concerned with the proper HVAC system(s) for the pump station and any other areas related to the Pump station. The following identifies a brief list of coordination points between HVAC and mechanical.
7.6.
Verify proper ventilation is provided, based on area classification and heat generated by pumps.
Verify with owner the desired room temperatures for the pump station and any other areas related to the pump station, and relate the information to HVAC engineer.
Verify proper heating system is provided to prevent freezing
Verify floor drains, sinks and hose bibs are coordinated with HVAC engineer
Coordinate Fire protection requirements with HVAC engineer.
Architectural There are a few coordination points between mechanical and architectural.
Confirm clearances between the bridge cranes and supporting structures Page | Chapter 7-2
OCT 2011
Confirm ton capacity of bridge crane for architectural signage
Confirm size of pumps for roof/floor hatch access openings if needed
Confirm maintenance and access walking clearance around all mechanical equipment is a minimum of 3’-0”
Coordinate location of sump pump, trench, and access to below if needed. Ladders, grating, etc. Do not place near or in front of any doors or required egress paths
Coordinate any wall penetrations of pipe or above grade penetrations
Coordinate height of overhead coiling door, if needed, for truck/equipment clearances, etc.
Page | Chapter 7-3
OCT 2011
8.
SAFETY ISSUES Most chemicals used for water or wastewater treatment require safety precautions and safety equipment. A list of safety equipment recommended for specific chemicals is indicated below:
Safety Guards around rotating equipment
Negative ventilation
Protective clothing
Rubber gloves
Rubber boots
Goggles
Face Shields
Respirator is not required
Eyewash and safety showers located at chemical fill station, near the chemical storage and feed systems and at each injection location. All eyewashes and safety showers should be served from the potable water system, not a utility water system.
Safety equipment should be specified and shown on the drawings where required (i.e., safety showers/eyewash, ventilation equipment). Local codes and OWNER preferences should be consulted for each project.
Page | Chapter 8-1
OCT 2011
9.
KEY MWH CONTACTS AND REFERENCES: MWH Contacts: i.
Tino Senon
ii.
Tim Ayvaz
iii.
George Tey
Page | Chapter 9-1
Cell No: 425 241-6842 Direct: 360 3870908) Cell No: 713 501-6784 Direct: 303 2912124 Cell No:626 272-1864 Direct: 626 5686259
OCT 2011
10.
REFERENCE DOCUMENTS
Page | Chapter 10-1
OCT 2011
This page left intentionally blank
Page | Chapter 10-2
ATTACHMENT A
PUMP STATION DESIGN PROCEDURE FLOW CHART
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PUMP STATION DESIGN PROCEDURE FLOW CHART PRELIMINARY DESIGN PHASE (PDP)
DESIGN DEVELOPMENT PHASE (DDP) CLIENT’S COMMENTS
- REVIEW BASIS OF DESIGN REPORT - DETERMINE DESIGN FLOW RANGE
DESIGN CRITERIA DEVELOPMENT
- DETERMINE STATIC HEADS - DETERMINE DISCHARGE PIPE LENGTH - PREPARE EXCEEDANCE FLOW RANGE CURVE - IDENTIFY FLUID PROPERTIES
- PROGRESS PRELIMINARY LAYOUT DEVELOPED DURING PDP
PREPARE PRELIMINARY PUMP STATION DESIGN LAYOUT
- DOCUMENTATION: FLUID PROPERTIES WORKSHEET - DETERMINE FRICTION FACTOR (C-VALUE) - DETERMINE PIPING LAYOUT
PREPARE HEADLOSS/TDH CALCULATION
- DOCUMENTATION:
- COORDINATE W/ I&C, DEVELOPMENT OF P&ID
- DETERMINE SIZE & LENGTH OF PIPELINE
- COORDINIATE STRUCTURAL EQUIMENT, FOUNDATION, VIBRATION, EQUIPMENT LOADS
COORDINATION W/ OTHER DISCIPLINES
- IDENTIFY DYNAMIC LOSSES - IDENTIFY MAX DESIGN POINT (Q&H) - IDENTIFY OPERATING ENVELOPE SYSTEM HEAD CURVES - DETERMINE NO. OF PUMPS - DETERMINE IMPELLER PROFILES USING SPECIFIC SPEED EQUATION - DETERMINE MAXIMUM SPEED USING SUCTION SPECIFIC SPEED EQUATION
- COODINATE W/ CIVIL SITE LAYOUT: PUMP STATION MUST BE ABOVE FLOOD ELEVATION, YARD PIPING ROAD ACCESS TO PUMP STATION TURNING RADIUS TO ALLOW TRUCK (SEMI) TRUNING RADUS OR MOBIL CRANE REACH DISTANCE, SITE DRAINAGE - COORDINATE W/ I&C ALL EQUIPMENT INSTRUMENTAITON AND OPERATIONAL SCENARIOS - DOCUMENTATION INPUT FROM OTHER DISCIPLINES - PUMP GENERAL - PUMP SPECS
DEVELOP PRELIMINARY SPECIFICATION OF MAJOR EQUIPMENT
- DETERMINE PUMP TYPE - DETERMINE NPSHr VERSUS NPSHa - SELECT PUMP CURVE
- PROVIDE STRUCTURAL BACKGROUND DRAWING OF PUMP ROOM SO THAT THEY CAN ESTIMATE WALL THICKNESS, COLUMN SIZE, ETC.
- PROVIDE ELECTRICAL W/ ELECTRICAL LOADS
(OPTIONAL) CCM REVIEW BASED ON SIZE & PROJECT COMPLEXITY
- DOCUMENTATION:
- VALVE GENERAL - VALVE SPECS - ELECTRIC MOTORS - COUNDUIT & CABLES - PRELIMINARY LOOP DESCRIPTION OF MAJOR SYSTEMS - MAJOR PIPING - MAJOR CIVIL WORK
- DOCUMENTATION:
- DOCUMENTATION
PUMP PERFORMANCE CURVE
PRELIMINARY SPECIFICATIONS
NPSH WORKSHEET
CONDUCT PEER REVIEW
- PLANT WATER DRAINAGE
- COORDINATE WALKWAYS, PLATFORM, DOORS WITH STRUCTURAL & ARCHITECTURAL
- ESTIMATE NPSH
- IDENTIFY STATIC HEADS
PLOT PUMP CURVE OVER SYSTEM HEAD CURVE
- INCLUDE FOR HOISTS & CRANES, HEADROOM CLEARANCE
- DETERMINE PIPE JOINTS & FITTINGS
TDH CALCULATIONS
PUMP SELECTION
- SHOW SPACE BETWEEN EQUIPMENT FOR O&M ACCESS FOR REMOVAL & INSTALLATION
PRELIMINARY DESIGN LAYOUT AND SECTIONS
- DETERMINE PIPE SIZE & VALVE TYPES
- DOCUMENTATION:
PLOT SYSTEM HEAD CURVES
- SHOW OUTLINE OF MAJOR EQUIPMENT: PUMPS, MOTORS, VFD, ELECTRIC GEARS, HVAC AND PIPING
- DETERMINE IF CONSTANT SPEED OR VFDs ARE REQUIRED - DETERMINE POR AND MCF LIMITS - OPTIMIZE PUMP EFFICIENCY AS CLOSE AS POSSIBLE TO 90% EXCEEDENCE FLOW - DETERMINE MOTOR NON-OVERLOADING-HP
- DOCUMENTATION
QUALITY REVIEW BY THE CHIEFS
REVIEW COMMENTS
- CHECK NPSHa VS NPSHr AT WORST FLOW CONDTION - DOCUMENTATION: SYSTEM HEAD CURVE W/ PUMP CURVE SUPERIMPOSED
CONTRACT DEVELOPMENT PHASE (CDP)
OPERATING ENVELOPE WORKSHEET
Pl otScal e: 2:1
- DETERMINE OPERATIONAL AND CONTROL PHILOSOPHY
CONFIGURE OPERATIONAL SCENARIOS
- DETERMINE SYSTEMWIDE REQUIREMENT ON HOW THE PUMP MUST OPERATE - WILL THE PUMPS BE CONTROLLED BY FLOW OR LEVEL
REFER TO SCR OF DESIGN FRAMEWORK
PROGRESS DWGS TO MEET DDP CRITERIA OF COMPLETION
CLIENT’S COMMENTS
- DETERMINE IF PUMPS ARE CONSTANT SPEED OR VFD - DOCUMENTATION:
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
PRELIMINARY OPERATIONAL DESCRIPTION
PREPARE SURGE ANALYSIS
PROPER PLANS AND SECTIONS
SUBMITTAL TO CLIENT
- DETERMINE SIMPLEST, SAFEST AND COST-EFFECTIVE SURGE PROTECTION SYSTEM - SIMULATE NORMAL STARTING & STOPPING OF PUMP, PLUS POWER FAILURE EVENT - DOCUMENTATION:
-
UPDATE ALL DRAWINGS, CALCULATIONS
-
SHOW ALL PLANS & SECTIONS, MAJOR & MINOR EQUIPMENT
-
SHOW ALL MAJOR & MINOR PIPING & VALVES
-
SHOW ALL CLEARANCES BETWEEN EQUIPMENT
-
COORDINATE W/ ALL DISCIPLINES
-
DOCUMENTATION DRAWINGS & SPECIFICATIONS
SURGE ANALYSIS REPORT SURGE ANLAYSIS WORKSHEET
CONDUCT PEER REVIEW
DETERMINE MATERIAL OF PUMP CONSTRUCTION
REFER TO SCR OF DESIGN FRAMEWORK
- SECURE TEST RESULTS OF FLUID CONSTITUENTS - DETERMINE PUMP MATERIALS - SUITABLE/COMPATIBLE WITH FLUID - CONSULT/CONFIRM WITH PUMP MANUFACTURER
Col orTabl e: bw.ctb
- UPDATE ALL SPECIFICATIONS - COMPARE ALL SPECIFICATIONS - COORDINATE SPECIFICATIONS W/ ALL DISCIPLINES
- DOCUMENTATION MATERIAL LIST SPECIFICATION
SUBMITTAL TO CLIENT
- SHOW PUMPS, MOTORS, ELECTRICAL GEARS, HVAC
PRELIMINARY DESIGN LAYOUT AND PUMP STATION CONFIGURATION
PROGRESS ALL SPECIFICATION SECTIONS
DESIGN CRITERIA, LARGE PIPING & VALVES
QUALITY REVIEW OF THE DRAWINGS AND SPECS BY THE CHIEFS
- PREPARE SUCTION CONFIGURATION - SHOW ACCESS - DOCUMENTATION PRELIMINARY LAYOUT WET WELL CONFIG. WORKSHEET
CLIENT’S COMMENTS
Model : Defaul t
(OPTIONAL) PHYSICAL MODEL STUDY OF SUCTION CONFIGURATION
PREPARE TECHNICAL MEMORANDUM
CONDUCT CCM REVIEW
INCORPORATE COMMENTS
- SUMMARIZE HYDRAULIC ANLAYSIS, PUMP MATERIALS SURGE ANLAYSIS, ANY ALTERNATIVE COMPARISON PREOVIDE RECOMMENDATION - DOCUMENTATION TECHNICAL MEMORANDUM
FINAL PRINTING OF CONTRACT DOCUMENT
- CHECK DESIGN CRITIERA - CHECK HYDRAULICS - CHECK OPERATION SCENARIO - CHECK PRELIMINARY LAYOUT - VALIDATE RECOMMENDATIONS - CHECK CONSTRUCTABILITY & SCHEDULE - DOCUMENTATION:
END
di agram .dgn
REVIEW COMMENTS
Fi l e: process fl ow
SUBMITTAL TO CLIENT
SCALE
SUBMITTED BY
WARNING 0
1
(PROJECT MANAGER’S NAME) NO SCALE
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
*
DESIGNED LICENSE NO.
DATE
DRAWN
*
PUMP STATION BEST PRACTICES
*
DESIGN PROCEDURE FLOW CHART
* CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
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ATTACHMENT B
TYPICAL TREATMENT PLANT PROCESS FLOW DIAGRAMS
G-1 : General Pump Types Conventional Surface Water Schematic Membrane Water Treatment Plant Schematic Wastewater Membrane General Schematic Conventional (BNR) with Primary Clarifiers – Wastewater Treatment Plant Schematic Conventional (BNR) Wastewater Treatment Plant Schematic
This page left intentionally blank
TURBIDITY
pH/TEMP
CHLORINE RESIDUAL
FINISHED WATER
SAMPLE #15
TURBIDITY
pH/TEMP
FLUORIDE RESIDUAL
CHLORINE RESIDUAL
CLEARWELL INFLUENT
SAMPLE #14
pH/TEMP
FLUORIDE RESIDUAL
CHLORINE RESIDUAL
CT END OF SECOND CHANNEL
SAMPLE #13
pH/TEMP
CHLORINE RESIDUAL
TURBIDITY
FILTER EFFLUENT COMMON
SAMPLE #12
PARTICLE COUNT (FILT #1 ONLY)
TURBIDITY
FILTER EFFLUENT
SAMPLE #4-#11
pH/TEMP
CHLORINE RESIDUAL
TURBIDITY
SETTLED WATER
SAMPLE #3
pH/TEMP
STREAMING CURRENT
COAGULATED WATER
SAMPLE #2
TURBIDITY
FWW EFFLUENT
SAMPLE #17
TURBIDITY
THICKENER DECANT
SAMPLE #16
TURBIDITY
CONDUCTIVITY/pH/TEMP
RAW WATER
SAMPLE #1
TO FLUSHING BASIN FOR FRWA PIPELINE FLUSHING & PLANT OVERFLOW
TO ADMIN/OPS BLDG LAB
TO ADMIN/OPS BLDG LAB M
ALT M TRANSFER 2
PUMP
2
2
ALT 8
STATION
FLASH MIX
2
2 3
4
BACKWASH
LAKE, 2
RIVER, M
PIPELINE
PUMPS
RAW
OVERFLOW
WELL OR
2
WATER RESERVOIR
7
M
1 M
M FILTER SURFACE
RAW WATER RESERVOIR BYPASS INTAKE PUMP
FLOW CONTROL
FLOW
STRUCTURE
DISTRIBUTION
FLOCCULATION
SEDIMENTATION
BASINS
BASINS
6
SURGE
WATER WASH
TANKS
FILTERS CT TANK
TRANSFER PUMPS
AIR
STRUCTURE
STORAGE TANK
5
TO SERVICE
SCOUR 9
SLUDGE
BLOWERS
M
AREA
FILTER TO WASTE PUMP FTW FLOW
TYPE
PLANT WATER
HIGH SERVICE PUMP STATION
WW
M
SYSTEM
UV DISINFECTION
SLUDGE 11
PUMP TYPE
FWW CLARIFIERS
RECYCLE PUMP FWW RECYCLE M 10
SLUDGE
WASTE WW EQUALIZATION BASIN
SLUDGE 11
PUMP
M
THICKENED SLUDGE HOMOGENIZING
M
TANK BYPASS SOLIDS THICKENERS M
PLANT DRAIN PUMP STATION M
CENTRATE 13
CENTRIFUGES 12
DRIED SLUDGE
TO LANDFILL
CENTRIFUGE FEED PUMP
THICKENED SLUDGE HOMOGENIZING TANK
(13) PLANT DRAIN PUMP STATION TYPE
(8) BACKWASH PUMP TYPE
(10) WASTE RECYCLE PUMP TYPE
VERTICAL TURBINE
VERTICAL TURBINE MIX FLOW
SUBMERSIBLE NON CLOG CENTRIFUGAL
HORIZONTAL SPLIT CASE
HORIZONTAL SPLIT CASE CENTRIFUGAL
SELF PRIMING NON CLOG CENTRIFUGAL
CENTRIFUGAL HORIZONTAL ANSI END SUCTION CENTRIFUGAL HORIZONTAL ANSI END SUCTION CENTRIFUGAL
HORIZONTAL NON CLOG CENTRIFUGAL (12) CENTRIFUGAL FEED PUMP TYPE
THICKENER DECANT RETURN BY GRAVITY
PROGRESSIVE CAVITY
(1) INTAKE PUMP TYPE
(2) SAMPLE PUMP TYPE
(3) TRANSFER PUMP TYPE
(4) FLASH MIX PUMP TYPE
(5) FILTER TO WASTE PUMP TYPE
(6) TRANSFER PUMP TYPE
VERTICAL TURBINE
VERTICAL TURBINE
VERTICAL MIX FLOW
HORIZONTAL END SUCTION
HORIZONTAL SPLIT CASE
VERTICAL TURBINE MIX FLOW
CENTRIFUGAL
CENTRIFUGAL
HORIZONTAL SPLIT CASE CENTRIFUGAL
HORIZONTAL CENTRIFUGAL
HORIZONTAL MIX FLOW CENTRIFUGAL
INCLINED SCREW
SELF PRIMING CENTRIFUGAL
INCLINED SCREW PUMPS
(7) FILTER SURFACE WATER WASH
(9) HIGH SERVICE PUMP TYPE
(11) SLUDGE PUMP TYPE (TWO LOCATIONS)
PUMP TYPE
DEEP WELL SUBMERSIBLE
REGENERATIVE TURBINE CENTRIFUGAL
VERTICAL TURBINE
HORIZONTAL NON CLOG CENTRIFUGAL
VERTICAL TURBINE HORIZONTAL NON CLOG
DRY PIT SUBMERSIBLE
VERTICAL TURBINE MIX FLOW
CENTRIFUGAL
VERTICAL TURBINE
HORIZONTAL ANSI END SUCTION
HORIZONTAL ANSI END SUCTION
CENTRIFUGAL
CENTRIFUGAL
HORIZONTAL SPLIT CASE CENTRIFUGAL
VERTICAL NON CLOG CENRIFUGAL
HORIZONTAL SPLIT CASE CENTRIFUGAL
HORIZONTAL ANSI END SUCTION
PROGRESSIVE CAVITY
CENTRIFUGAL HORIZONTAL ANSI END SUCTION
SUBMERSIBLE NON CLOG CENTRIFUGAL
CENTRIFUGAL
VERTICAL TURBINE DEEP WELL HORIZONTAL SPLIT CASE SUBMERSIBLE (RITZ)
CONVENTIONAL SURFACE WATER SCHEMATIC REV120908
MEMBRANE CLEANING WASTE
PROCESS AND CONTAINMENT DRAINS SCRUBBER WASTE
MONITORING WELLS WASTE SUMP PUMPS
5 TO ATMOSPHERE
WASTE
BYPASS
SUMP
TO ATMOSPHERE BLEND CARTRIDGE FILTERS E X
H A U
ALTERNATE
S T
G A S S PERMEATE
T A
7
C K RECIRCULATION 2-STAGE
PUMP
ODOR SCRUBBER
RAW WATER LAKE, 3
2
RIVER, 1
PIPELINE
INTER-STAGE
CARTRIDGE
PLANT WATER
BOOSTER PUMP
FILTERS FIRST STAGE
(NOTE 1)
SYSTEM SECOND STAGE
PROCESSES
PRIMARY TREATMENT PROCESS
BLOWERS
DEGASIFIER
TO DISTRIBUTION
CLEARWELL
8
TRANSFER
TOWERS
PUMPS POST-TREATMENT PROCESSES
HIGH SERVICE PUMPS
GROUND STORAGE
OVERFLOW
PUMPS
OVERFLOW
R.O. FEED
CONCENTRATE
PRE-TREATMENT
BYPASS
6 START-UP
WELL OR
STORM WATER DETENTION
STORM WATER STORM WATER
DETENTION AREAS
DETENTION
INJECTION WASTE
4
INJECTION PUMP
INJECTION WELL(S)
(1) RAW WATER PUMP TYPE
(2) R.O. FEED PUMP TYPE
(3) INTERSTAGE BOOSTER PUMP TYPE
(4) INJECTION PUMP TYPE
(5) WASTE SUMP PUMP TYPE
(6) TRANSFER PUMP TYPE
(7) RECIRCULATION PUMP TYPE
(8) HIGH SERVICE PUMP TYPE
DEEP WELL SUBMERSIBLE
VERTICAL TURBINE
HORIZONTAL CENTRIFUGAL
VERTICAL TURBINE
VERTICAL TURBINE MIX FLOW
VERTICAL TURBINE MIX FLOW
HORIZONTAL END SUCTION
VERTICAL TURBINE
VERTICAL TURBINE DEEP WELL
HORIZONTAL SPLIT CASE CENTRIFUGAL
R.O. VESSEL TURBO
HORIZONTAL SPLIT CASE CENTRIFUGAL
HORIZONTAL NON CLOG CENTRIFUGAL
HORIZONTAL END SUCTION CENTRIFUGAL
HORIZONTAL END SUCTION CENTRIFUGAL
VERTICAL TURBINE
HORIZONTAL ANSI END SUCTION
SUBMERSIBLE NON CLOG
HORIZONTAL ANSI END SUCTION
HORIZONTAL SPLIT CASE CENTRIFUGAL
CENTRIFUGAL
VERTICAL TURBINE
CENTRIFUGAL
CENTRIFUGAL
HORIZONTAL SPLIT CASE CENTRIFUGAL
HORIZONTAL END SECTION CENTRIFUGAL HORIZONTAL SPLIT CASE SUBMERSIBLE (RITZ)
NOTES ENGINEER TO DELETE INTERSTAGE PUMPING IF NOT INCLUDED IN PROJECT.
MEMBRANE WATER TREATMENT PLANT SCHEMATIC REV120908
PRELIMINARY
SECONDARY
TERTIARY + EFFLUENT MANAGEMENT
FLOW MEASUREMENT -
6 MM
GRIT
2 MM
ANAEROBIC
ANOXIC
AERATION
MAGMETER
COARSE SCREENING
REMOVAL
FINE SCREENS
ZONE
ZONE
ZONE
MEMBRANE TANKS
UV DISINFECTION
9
MEMBRANE
COMPRESSED
BLOWER
AIR
PLANT NON-POTABLE WATER SYSTEM PUMP RECLAIMED WATER STORAGE TANK
SCUM PUMPS
6
8
MLT
MEMBRANE CLEANING
10
PUMP
RECLAIMED PUMPING
UV
STATION
7 MM 1 5 MLR RAW SEWAGE
PERMEATE
PUMPS
ML TRANSFER
(INFLUENT)
(TRANSFER)
FORWARD 4
PUMP
PUMP
TO IRRIGATION 2
SYSTEM
PROCESS 3
BLOWER
GRIT PUMPS
AMLR PUMPS
11
MIXING AIR BLOWERS
WAS
15
PUMPS
DEEP INJECTION WELL PUMP STATION DEEP INJECTION WELL 13
14
DEWATERING FEED
SLUDGE
PUMPS
TRANSFER
16
MIXING OR
SLUDGE STORAGE,
REJECT
AEROBIC OR
HOLDING
ANAEROBIC DIGESTERS
TANK
RECIRCULATION PUMPS
PLANT DRAINS
12
PLANT LIFT STATION
(1) RAW SEWAGE PUMP TYPE
(2) GRIT PUMPS
(3) AERATION MIXED LIQUOR RECYCLE (AMLR) PUMPS
(5) MIXED LIQUOR (ML) TRANSFER PUMPS
(7) PERMEATE TRANSFER PUMPS
(9) PLANT NON-POTABLE WATER PUMPS
(11) DEEP WELL INJECTION PUMPING PUMPS
(13) SLUDGE TRANSFER PUMPS
(15) WAS PUMPS
HORIZONTAL NON CLOG CENTRIFUGAL
HORIZONTAL RECESSED IMPELLER
PROPELLER
HORIZONTAL END SUCTION
HORIZONTAL END SUCTION
VERTICAL TURBINE
VERTICAL TURBINE
HORIZONTAL NON CLOG CENTRIFUGAL
HORIZONTAL NON CLOG
CENTRIFUGAL
CENTRIFUGAL
VERTICAL NON CLOG CENTRIFUGAL
VERTICAL DRYPIT RECESSED IMPELLER
HORIZONTAL NON CLOG CENTRIFUGAL
HORIZONTAL END SUCTION
HORIZONTAL END SUCTION
VERTICAL NON CLOG CENTRIFUGAL
CENTRIFUGAL
CENTRIFUGAL
VERTICAL TURBINE
VERTICAL TURBINE
CENTRIFUGAL
INCLINED SCREW
VERTICAL NON CLOG ROTARY LOBE
CENTRIFUGAL
PLUNGER
ROTARY LOBE
PROGRESSIVE CAVITY
PROGRESSIVE CAVITY
(14) DEWATERING FEED PUMPS
(16) MIXING OR RECIRCULATION PUMPS
HORIZONTAL SPLIT CASE CENTRIFUGAL
VERTICAL TURBINE SOLIDS HANDLING SUBMERSIBLE NON CLOG CENTRIFUGAL DRY PIT SUBMERSIBLE NON CLOG CENTRIFUGAL
(4) MIXED LIQUOR RECYCLE (MLR) PUMPS
(6) SCUM PUMPS
(8) MEMBRANE CLEANING PUMPS
(10) RECLAIMED WATER PUMPING STATION PUMPS
(12) PLANT LIFT STATION PUMPS
PROPELLER
HORIZONTAL SCREW CENTRIFUGAL
HORIZONTAL END SUCTION
VERTICAL TURBINE
SUBMERSIBLE NON CLOG CENTRIFUGAL
PROGRESSIVE CAVITY
SCREW CENTRIFUGAL
CENTRIFUGAL HORIZONTAL NON CLOG CENTRIFUGAL
HORIZONTAL ANSI END SUCTION CENTRIFUGAL HORIZONTAL SPLIT CASE CENTRIFUGAL
WASTEWATER MEMBRANE
GENERAL SCHEMATIC
REV120908
PRELIMINARY
SECONDARY
TERTIARY + EFFLUENT MANAGEMENT
FLOW MEASUREMENT -
6 MM
GRIT
PRIMARY
INFLUENT
ANAEROBIC
ANOXIC
AERATION
SECOND
MAGMETER
COARSE SCREENING
REMOVAL
CLARIFIERS
CHANNEL
ZONE
ZONE
ZONE
ANOXIC
REAERATION
EFFLUENT
SECONDARY
CHANNEL
CLARIFIERS
FILTERS
DISINFECTION TANK
10
PLANT NON-POTABLE WATER SYSTEM DISINFECTION
RECLAIMED
TANK (CCT)
WATER STORAGE TANK
11
MM 1 9 MLR PUMPS
RAW SEWAGE
TRANSFER
(INFLUENT)
RECLAIMED PUMPING
3
STATION
PROCESS
7
6
BLOWER
FILTER
SCUM BACKWASH 4
BACKWASH
HOLDING TANK TO IRRIGATION
RAS
SYSTEM
8
FILTER 12
BACKWASH RETURN
DEEP INJECTION
4
WELL PUMP STATION RAS
DEEP INJECTION WELL
5
WAS
MIXING AIR BLOWERS
REJECT
5
HOLDING 5
TANK
WAS
GRIT PUMPS 14 6 SLUDGE
15
SCUM
TRANSFER
DEWATERING FEED PUMPS
16
MIXING OR RECIRCULATION PUMPS
PLANT
SLUDGE STORAGE,
DRAINS
AEROBIC OR ANAEROBIC DIGESTERS
13
PLANT LIFT STATION
(1) RAW SEWAGE PUMP TYPE
(3) MIXED LIQUOR RETURN (MLR) PUMPS
(5) WAS PUMPS
(7) FILTER BACKWASH PUMPS
(9) TRANSFER PUMPS
(11) RECLAIMED WATER PUMPING STATION PUMPS
(13) PLANT LIFT STATION PUMPS
(15) DEWATERING FEED PUMPS
HORIZONTAL NON CLOG CENTRIFUGAL
PROPELLER
HORIZONTAL NON CLOG CENTRIFUGAL
HORIZONTAL END SUCTION CENTRIFUGAL
HORIZONTAL END SUCTION
VERTICAL TURBINE
SUBMERSIBLE NON CLOG CENTRIFUGAL
PROGRESSIVE CAVITY
VERTICAL NON CLOG CENTRIFUGAL
HORIZONTAL NON CLOG CENTRIFUGAL
VERTICAL NON CLOG CENTRIFUGAL
VERTICAL TURBINE
ROTARY LOBE
HORIZONTAL SPLIT CASE
CENTRIFUGAL HORIZONTAL END SUCTION VERTICAL TURBINE INCLINED SCREW
CENTRIFUGAL HORIZONTAL SPLIT CASE
VERTICAL TURBINE SOLIDS HANDLING SUBMERSIBLE NON CLOG CENTRIFUGAL DRY PIT SUBMERSIBLE NON CLOG CENTRIFUGAL
(4) RAS PUMPS
PROGRESSIVE CAVITY
CENTRIFUGAL
HORIZONTAL NON CLOG CENTRIFUGAL VERTICAL NON CLOG CENTRIFUGAL (6) SCUM PUMPS
(8) FILTER BACKWASH RETURN PUMPS
(10) PLANT NON-POTABLE WATER PUMPS
(12) DEEP WELL INJECTION PUMPING PUMPS
(14) SLUDGE TRANSFER PUMPS
(16) MIXING OR RECIRCULATION PUMPS
HORIZONTAL SCREW CENTRIFUGAL
HORIZONTAL NON CLOG CENTRIFUGAL
VERTICAL TURBINE
VERTICAL TURBINE
HORIZONTAL NON CLOG CENTRIFUGAL
SCREW CENTRIFUGAL
VERTICAL SCREW CENTRIFUGAL
VERTICAL NON CLOG CENRIFUGAL
HORIZONTAL ANSI END SUCTION
HORIZONTAL END SUCTION
VERTICAL NON CLOG CENTRIFUGAL
CENTRIFUGAL
CENTRIFUGAL
VERTICAL TURBINE SOLIDS HANDLING (2) GRIT PUMPS HORIZONTAL SCREW CENTRIFUGAL HORIZONTAL RECESSED IMPELLER VERTICAL SCREW CENTRIFUGAL VERTICAL DRYPIT RECESSED IMPELLER
VERTICAL MIX FLOW
ROTARY LOBE
SUBMERSIBLE NON CLOG CENTRIFUGAL PLUNGER PROGRESSIVE CAVITY
CONVENTIONAL (BNR) WITH PRIMARY CLARIFIERS - WASTEWATER TREATMENT PLANT SCHEMATIC REV120908
PRELIMINARY
SECONDARY
TERTIARY + EFFLUENT MANAGEMENT
FLOW MEASUREMENT -
6 MM
GRIT
INFLUENT
ANAEROBIC
ANOXIC
AERATION
SECOND
MAGMETER
COARSE SCREENING
REMOVAL
CHANNEL
ZONE
ZONE
ZONE
ANOXIC
REAERATION
EFFLUENT
SECONDARY
CHANNEL
CLARIFIERS
FILTERS
DISINFECTION TANK
10
PLANT NON-POTABLE WATER SYSTEM DISINFECTION
RECLAIMED
TANK (CCT)
WATER STORAGE TANK
11
MM 1 9 MLR PUMPS
RAW SEWAGE
TRANSFER
(INFLUENT)
RECLAIMED PUMPING
3
STATION
PROCESS
7
6
BLOWER
FILTER
SCUM BACKWASH
BACKWASH
HOLDING TANK TO IRRIGATION SYSTEM
8
FILTER 12
BACKWASH RETURN
DEEP INJECTION
4
WELL PUMP STATION
RAS
DEEP INJECTION WELL
5
WAS
MIXING AIR BLOWERS 2
REJECT HOLDING GRIT
TANK
PUMPS
14
15
DEWATERING FEED
SLUDGE
PUMPS
TRANSFER
16
MIXING OR
PLANT
SLUDGE STORAGE,
RECIRCULATION PUMPS
DRAINS
AEROBIC OR ANAEROBIC DIGESTERS
13
PLANT LIFT STATION
(1) RAW SEWAGE PUMP TYPE
(3) MIXED LIQUOR RETURN (MLR) PUMPS
(5) WAS PUMPS
(7) FILTER BACKWASH PUMPS
(9) TRANSFER PUMPS
(11) RECLAIMED WATER PUMPING STATION PUMPS
(13) PLANT LIFT STATION PUMPS
(15) DEWATERING FEED PUMPS
HORIZONTAL NON CLOG CENTRIFUGAL
PROPELLER
HORIZONTAL NON CLOG CENTRIFUGAL
HORIZONTAL END SUCTION CENTRIFUGAL
HORIZONTAL END SUCTION
VERTICAL TURBINE
SUBMERSIBLE NON CLOG CENTRIFUGAL
PROGRESSIVE CAVITY
VERTICAL NON CLOG CENTRIFUGAL
HORIZONTAL NON CLOG CENTRIFUGAL
VERTICAL NON CLOG CENTRIFUGAL
VERTICAL TURBINE
ROTARY LOBE
HORIZONTAL SPLIT CASE
CENTRIFUGAL HORIZONTAL END SUCTION VERTICAL TURBINE INCLINED SCREW
CENTRIFUGAL HORIZONTAL SPLIT CASE
VERTICAL TURBINE SOLIDS HANDLING SUBMERSIBLE NON CLOG CENTRIFUGAL DRY PIT SUBMERSIBLE NON CLOG CENTRIFUGAL
(4) RAS PUMPS
PROGRESSIVE CAVITY
CENTRIFUGAL
HORIZONTAL NON CLOG CENTRIFUGAL VERTICAL NON CLOG CENTRIFUGAL (6) SCUM PUMPS
(8) FILTER BACKWASH RETURN PUMPS
(10) PLANT NON-POTABLE WATER PUMPS
(12) DEEP WELL INJECTION PUMPING PUMPS
(14) SLUDGE TRANSFER PUMPS
(16) MIXING OR RECIRCULATION PUMPS
HORIZONTAL SCREW CENTRIFUGAL
HORIZONTAL NON CLOG CENTRIFUGAL
VERTICAL TURBINE
VERTICAL TURBINE
HORIZONTAL NON CLOG CENTRIFUGAL
SCREW CENTRIFUGAL
VERTICAL SCREW CENTRIFUGAL
VERTICAL NON CLOG CENRIFUGAL
HORIZONTAL ANSI END SUCTION
HORIZONTAL END SUCTION
VERTICAL NON CLOG CENTRIFUGAL
CENTRIFUGAL
CENTRIFUGAL
VERTICAL TURBINE SOLIDS HANDLING (2) GRIT PUMPS HORIZONTAL SCREW CENTRIFUGAL HORIZONTAL RECESSED IMPELLER VERTICAL SCREW CENTRIFUGAL VERTICAL DRYPIT RECESSED IMPELLER
VERTICAL MIX FLOW
ROTARY LOBE
SUBMERSIBLE NON CLOG CENTRIFUGAL PLUNGER PROGRESSIVE CAVITY
CONVENTIONAL (BNR) WASTEWATER TREATMENT PLANT SCHEMATIC REV120908
ATTACHMENT C DESIGN OF TRENCH-TYPE WET WELLS FOR PUMPING STATIONS
By Robert L. Sanks, PE, PhD and Theodore T. Williams
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DESIGN OF TRENCH-TYPE WET WELLS FOR PUMPING STATIONS
To be published May 2008 in Pumps & Systems magazine By Robert L. Sanks, PE, PhD and Theodore T. Williams In trench-type wet wells, the pump intakes are placed near the bottom of a deep, narrow trench coaxial with the inlet pipe but well below it. See Figure 1. The closely confining walls of the trench prevent cross currents and hence create a good hydraulic environment for the pump intakes. The trench works very well for both water and wastewater. The ramp shown in Figure 1 is omitted in clear water applications, and the row of pumps starts immediately downstream from the end of the inlet pipe. Pumping stations with capacities in the range of as little as 2.5 Mgal/d to as much as 220 Mgal/d for both water and wastewater are currently in service and performing well. Some of these installations are more than 40 years old with
self-cleaning by using only the main pumps. Other types of wet wells must be cleaned manually or by vacuum truck. During the cleaning cycle in a trench-type wet well, all scum, sludge, grit, gravel, rags and other trash are swept into the last pump by water accelerated to a high velocity by flowing down the curved ramp. Cleaning can be completed in a few (typically between one and three or four) minutes with no manual labor beyond the touch of a button. The process can be automated to occur at any wanted time intervals such as once every three days or once per week. Because the trench can so easily be kept clean and odor-free, this type of wet well can be placed anywhere (in residential, commercial, or business districts) without adverse odor Water guide Water guide Flow splitter end Flow splitter impact. Sluce Fillet-45° gate Trench-type wet wells are gaining popularity in the 2D SECTION A-A Midwest, South, and East coast of the United States, 2.5D 2.5D D 0.75D min min 0.3 m/s (1.0 ft/s) and they are already so max above trench PLAN popular on the West coast Flow splitter that some large utilities have Fillet- 45° Water guide Flow splitter A adopted them as standard. B Min level Note 3 0.38D Recommended 45-63° Anti-rotation baffle dimensions in terms of D (outside diameter of the r2 SECTION B-B S 2D A min pump intake suction bell) r1 NOTES are given in American 45° B 1. Flow splitter and fillets may be omitted 0.5D 0.38D in a trench less than 1.0 m (39 in.) wide. National Standard for Pump Lower floor as needed at last pump 2. r1 > 2.33 x v 2/2g where v = velocity at Intake Design (ANSI/HI 9.8LONGITUDINAL SECTION top of ramp (2D min), r2 > 1.25D, 45° MWH takes tangent between r1 and r2 . 2007) [1] reproduced in exception to HI, 3. 1.2 m/s (4 ft/s) max wet pit pumps, Sequent depth Figure 1. They were 1.0 m/s (3 ft/s) max dry pit pumps and recommends 30° 4. > 45° smooth surface (plastic lining) developed by years of both 0.5D min a submergence of 5. > 60° concrete surface model and prototype testing. Fillet- 45° 6. S > (1+2.3F )D 4D 0.25D Vanes 7. See Appendix D for details and tutorials However, some Cone Figure 1. Dimensions of open trench-type wet wells for wastwater. Taken from American recommendations are still National Standard for Pump Intake Design, ANSI/HI 9.8-2007 occasionally ignored, and the result is usually a flawed no indication of poor or unacceptable pump product that will not give satisfactory performance. performance. The feature that makes the trench-type wet well so attractive to those wastewater operators who have used one is its ability for D
1
If the disparity between peak wet weather flow and average dry weather flow is large, energy use can be decreased and flow matching improved by installing more pumps and in two different sizes so as to place most of the expected average dry weather flow rates in the pumps’ Preferred Operating Region. Using more pumps, however, increases capital and maintenance costs, and decreasing the size of the last pump adversely affects cleaning. Decisions here depend on the artfulness of the designer.
The purpose of this paper is to assist designers by giving the reasons for the recommendations in ANSI/HI 9.8. CHOOSING PUMPS This subject is covered thoroughly in both second and third editions of Pumping Station Design, Chapter 12 [2, 3]. In addition, some considerations specific to trench-type wet wells are given below. Types of Pumps Any type of water or wastewater pump (dry pit centrifugal, vertical turbine solids handling, or both dry pit and wet pit submersible solids handling pumps) can be used in trench-type wet wells. Dry pit pumps can be used by installing a flare for the suction bell followed immediately by an elbow (preferably long radius) and a horizontal pipe to the dry well. Submersible pull-up pumps can be used by casting a recess for the discharge elbow in the side of the trench; after the elbow and discharge pipe are placed, the recess can be filled with lean concrete. Column pumps are ideal in trenches.
Effect of number of pumps on cleaning Cleaning is accomplished by dewatering the wet well with the last main pump, so the pump operates under the severe service conditions of inadequate submergence and inadequate net positive suction head. It is therefore desirable to reduce running time during cleaning as much as possible. If the wet well is cleaned when inflow rate to the pumping station is, say, half the capacity of the last pump, then the net dewatering flow rate is also about half the last pump's capacity. If the pumping station contains three pumps (one is a standby), the net dewatering flow rate would be about 25 percent of the total station capacity. Increasing the number of pumps to four reduces the dewatering rate to about 17 percent of the station capacity, and, of course, reduces the scouring potential as well. The result is increased running time for the pump and reduced effectiveness of cleaning. Keep the number of pumps to a minimum commensurate with other considerations such as providing for minimum flows. Analyze each set of pumps using Trench2.0 [4], a program for calculating velocity and depth of water, Froude number, and sequent depth along the trench at pumpdown. Velocities less than about 7 ft/s and Froude numbers less than 3.5 are not very effective. For long wet wells, velocities can be increased by three ways: (1) widening flow splitters and fillets to increase the hydraulic radius, (2) covering the bottom with plastic
Number of pumps An ideal number is three; two pumps to carry the maximum load plus a standby. If they are variable speed units, the lowest flow rate that can be pumped is usually about 25 percent (half the capacity of a single pump) of the station capacity. Check with the manufacturer; some machines can pump at lesser capacities. All centrifugal pumps have a lower limit, however, and below the tolerable flow rate for a single pump, the pump must be turned off and on as with constant speed pumps. That may be a problem for downstream processes. Sedimentation basins are upset by sudden changes in incoming flow. Other processes, such as chlorination and de-chlorination may not meet requirements at all with sudden changes in flow rates. Confer with the treatment plant designer. 2
better), and (3) shedding of stringy material by making vane noses smooth, round, and inclined less than 45 degrees to the streamlines. As cast iron should not be welded, vanes can be bolted to cast iron flares used as suction bells. Of course, vanes can be welded in fabricated steel suction bells. For clear water applications, the vanes can A A extend the full width of the flare. Four vanes work Plan fairly well, but more are better. Similar to the wastewater vane Section A-A application, Figure 3. Straightening vanes in a suction bell for clear water vanes can be bolted to cast iron flares used as suction bells. Vanes in fabricated steel bells can be welded to the bell.
coatings or linings, and (3) sloping the floor beginning at the point where the velocity is too low. Use a safety factor, because, as friction factors are only estimates, hydraulic calculations are never precise. For pumping clean water, there is no need to clean the wet well, hence no need for the ramp, and no need to limit the number of pumps except for considerations of cost and maintenance effort. NORMAL PUMPING Water should flow into the wet well from a straight pipe (or channel) at least 8 pipe diameters long and coaxial with the trench to prevent deleterious cross-currents in the basin. The incoming current flows above the trench to the end wall, dives and flows upstream along the bottom of the trench. The flow that passes pump intakes joins the incoming flow near the top of the ramp. Swirling The narrow trench tends to keep currents evenly distributed, but swirling is sometimes greater than allowed in ANSI/HI 9.8. Although not mentioned in that publication, swirling can be controlled by adding straightening vanes (Figures 2 and 3) in the suction bell or in the horizontal pipe between the suction elbow and a dry pit pump. For wastewater applications, the vane design should allow for: (1) a A A sphere passageway of at least 3 in. and at Plan least equivalent to the pump's passageway , (2) at least four vanes Section A-A (six are Figure 2. Straightening vanes in a suction bell 3"
M
in
Entrance Baffle Another means for improving performance, especially for reducing swirling and changing a "good pump environment" to an "ideal pump environment" is to reduce incoming currents with a baffle. Almost any baffle that intercepts the incoming current is beneficial, but a large, vertical rectangular baffle that forces flow under it as well as around its sides is superb. A horizontal baffle is easier to install, but it can be a rag catcher and it forces all the current to go over it or under it and not around the sides. Vertical baffles (see Figure 4) were found in model tests to be more effective than horizontal ones in eliminating swirling, and in a prototype, rags can slide down and off of them. The best width was 5/6 Dp, which for this 18 Mgal/d wet well just happens to equal D. The best bottom elevation was D/2 below 3
the inlet invert, and the best location was 60 percent of the distance from the end of the pipe to the centerline of the first pump. The baffle can, however, be moved back and forth 5'-0"
Vortices Strong vortices form at the trench floor under suction bells and at the trench walls about 0.28 D below the bells. As vortices tend to cause vibration and cavitation, they should either be eliminated or at least attenuated. Otherwise, impellers and casings should be made of material more resistant than cast iron. Addition of nickel to cast iron is a partial palliative, but there are other metals far more cavitation (but not vibration) resistant. Side wall vortices can be eliminated by fillets sloped 45 degrees if sufficiently high. The ANSI/HI 9.8 recommendations for upstream suction bells are D/2 for floor clearance and 3/8 D for fillet height thereby placing the top of the fillet D/8 below the bell rim--a safety factor of about 2. Floor vortices can be virtually eliminated by a flow splitter with 45-degree sides and also 3/8 D high. Flow splitters with base width equal to height (side slopes of 63.4 degrees) are the steepest that can keep floor vortices under reasonable control. A slope of 45 degrees is preferable if it leaves room for workers' feet during installation. In clear water applications, cones under suction bells are also effective at eliminating floor vortices. The diameter of the cone must be twice the floor clearance and the apex must be in the plane of the bell rim. Four, or preferably six, vanes can reduce swirling to much less than the maximum allowed in ANSI/HI 9.8. Some hydraulic model testing experts greatly prefer flow splitters instead of cones. Trenches narrower than 38 inches are physically too confining for workers. If there are two duty pumps in a trench, that difficulty essentially precludes the use of fillets and flow splitters for capacities much less than about 10 Mg/d. Just omit flow splitters and fillets for smaller pumping stations and use materials more resistant to cavitation than gray cast iron. Many trench-type stations that have no fillets or flow splitters but do have nickel in the iron have operated very satisfactorily for many years.
10'-0"
Railing Walkway
Pipe or box beam
5'-0"
Ø30"
HWL 2'-11"
Inlet baffle 1'-0.5" 5'-2.5"
2'-1" Ø2'-1"
1'-0.5" (3" Min)
1'-0.5" 9.4"
9.4" 4'-2"
Figure 4. Cross-section of 18-Mgal/d wet well with baffle for reducing incoming currents. Walkway makes it easy to access pump intakes and to wash grease off sidewalls.
with only minor effects. The baffle should be a thin (say, 4 in.) box section, because a simple plate would probably flutter. It can be supported in many different ways. The way shown in Figure 4 is to install a box or pipe beam (that can resist both bending and torsion) above high water level (HWL). Another way is by a beam above HWL and another (or even the roof) above that. Another way is by means of a beam above HWL and another at the bottom of the baffle, but the lower beam would prevent shedding stringy material. The structure should be stiff enough to resist vibration due to von Karman vortices. Use stainless steel and fill box sections with concrete to resist microbial corrosion, which attacks even stainless steel in stagnant wastewater. The need for and the design of baffles should be established by hydraulic model testing.
4
ft or more with a velocity of 12 ft/s or more and if the Froude number at the end of the wet well were at least 3. The cleaning performance indicated by Figure 5 (depth 0.27 ft, velocity 18 ft/s at foot of ramp and Froude number 6.2 at end of trench) is superb.
Uneven Distribution of Throat Velocities ANSI/HI 9.8 limits the variation in throat velocities to 10 percent. Uneven and fluctuating throat velocities in the suction bell have not been a problem in trench-type wet wells with column, wet pit submersible, horizontal dry pit, or vertical dry pit pumps when the vertical dry pit pump is preceded by a long-radius reducing elbow wherein the exit velocity is at least twice the inlet velocity.
Cleaning Time The time can be calculated by estimating the volume to be discharged and the net flow rate into and out of the basin. The volume in the sewer pipe is that between the drawdown curve and the original depth. If 18 Mgal/d (27.9 ft3/s) fills a 3.0 ft pipe, 7.8 ft3/s fills it to a depth of 1.25 ft. (See Figure B-5 in Pumping Station Design [3].) Critical depth is 0.88 ft from UnifCrit2.2 [5], so drawdown at the end of the pipe is 1.25 - 0.88 = 0.37 ft. If the drawdown curve is roughly 600 ft long at the end of pump-down, the volume, V1, in a parabolic wedge is
SELF-CLEANING The wet well is cleaned by dewatering it rapidly (pump-down) with the last pump. Choose a time when the inflow is about half the capacity of the last pump. As the water level falls below the top of the ramp, a hydraulic jump is formed. As the water level continues to fall and the hydraulic jump approaches the foot of the ramp, the currents wash floating material to the last pump where it is entrained in the fluid and pumped out. As the jump progresses along the floor, it suspends all remaining debris and the currents wash the debris into the pump. Consider, for example, a wet well featuring three equal variable-speed pumps (two duty pumps) with 25-in. suction bells having an entrance velocity of 4 ft/s--an 18 Mgal/d facility. A single duty pump would have a capacity of about 10 Mgal/d (15.5 ft3/s). Assume cleaning occurs when the inflow is 7.8 ft3/s. At the bottom of the ramp, the velocity is about 17 ft/s from Figure 5, and the depth of flow is only 0.3 ft. The flow splitter ends at Node 15 and the average water depth drops accordingly. The Froude number never falls much below 6 and the sequent depth (height of jump) remains above 1.3 ft. As the last bell should be no higher than D/2 below the sequent depth to prevent loss of prime, the bell should be at an elevation no higher than 1.3 - 25/ (2x12) = 0.26 ft above the upstream floor. It should also be D/4 or 0.52 ft above the floor below, so the floor must be lowered by 0.52 - 0.26 = 0.26 ft. Cleaning would be adequate if, at the foot of the ramp, the depth of water were 0.1
V1, Approximate volume of drawdown, 600 x 3 x 0.37 x (1/3) ≈ 220 ft3 V2, Volume above trench, 3 1.85(4.17+8.0)(1/2)21.04 ≈ 240 ft V3, Top of trench to 0.3 ft above floor, 4.97 x 4.17 x 17 ≈ 350 ft3 V4, Empty two column 2 (18/12) π/4 x 2 x 30 ≈ 110 ft3
pumps
Pumping at 15.5 ft3/s with an inflow of 7.8 ft3/s gives a net discharge-pumping rate of 7.7 ft3/s. The volume in the wet well is 220 + 240 + about half of 350 = 635 ft3. The time required to pump this amount is 635/7.7 = 82 s. The pump probably loses about 15 percent of its capacity at low submergences, so the rest of the water (110 + 350/2 = 285 ft3) is discharged at a net flow rate of 15.5 x 0.85 7.8 = 5.4 ft3/s. This part takes about 53 s. The total time is about 2.3 minutes. If two pumps are used to discharge the 635 ft3, the net pumping rate is 27.9 - 7.8 = 27.1 ft3/s, and the 82 s shrinks to 23 s for a net cleanout time of about 1.3 minutes.
5
Details… Assumptions… Web Address… The Spreadsheet… Version 2.0 Posted on web January 3, 2003. Date: January 31, 2007 Project Title: 18 MGD Trench-Type Self-Cleaning Wet Well Client: N/A Location: NA Job No.: N/A Calculation by: Sanks Remarks: Save this worksheet unaltered to use as the default. Program developed by Dr. Joel Cahoon, Montana State University. Access: http://www.coe.montana Uniform Flow Depth in the Circular Inlet Channel Section A - B Section B - C b= 4.17 ft b= 4.17 ft 7.80 cfs Flow Rate = bf = bf = 2.61 ft 2.61 ft 0.0015 ft/ft Slope = zf = bs = 1.56 ft 1.00 3.00 ft Diameter = zf = zs =
1.00
yf =
0.78 ft
Ramp Height (ft) =
5.90
Flow Area =
ys =
0.78 ft
Upper Radius (ft) =
4.20
Wetted Perimeter =
3.87 ft 0.59 ft
yf = nconcrete =
1.00
Manning's n =
0.78 ft
nsplitter =
0.009
Lower Radius (ft) =
2.60
Hydraulic Radius =
nconcrete =
0.011
Length 1 (ft) = Length 2 (ft) =
8.90 4.20
Velocity = r.h.s. =
EL1 = EL2 = r1 = r2 = L1 = L2 =
5.9 0.0 4.2 2.6 8.9 4.2
ft ft ft ft ft ft
Vertical Lines for L1 and L2:
0.012 1.08 ft 2 2.30 ft
Flow Depth =
0.011
i 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
Bed Elevation Data Scroll down for diagram.
Author…
3.39 ft/sec 0.0000 cfs
21.82 21.82
0.00 5.90
17.62 17.62
0.00 5.90
8.72 8.72
0.00 5.90
x(i) 0.00 0.82 1.61 2.33 2.97 3.95 4.92 5.90 6.88 7.39 7.87 8.32 8.72 11.68 14.65 18.67 19.72 20.77 21.82
y(i) 5.90 5.82 5.58 5.19 4.67 3.69 2.72 1.74 0.76 0.44 0.20 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00
7.00 Distance from Elevation
Run Run
Vertical Flow
Water Surface
Mean
Froude
Depth Elevation
Velocity
Number
Energy
F
E, (ft)
1.11 1.48 2.08 2.75 3.48 4.51 5.36 6.10 6.76 6.97 7.07 7.10 7.07 6.67 6.30 6.76 6.58 6.41 6.24
6.95 6.95 6.94 6.93 6.91 6.85 6.74 6.59 6.39 6.33 6.24 6.15 6.08 5.60 5.17 4.58 4.42 4.27 4.13
Normal Flow
6.00
Control
Head
Depth
Node
x, (ft)
z, (ft)
yv, (ft)
y, (ft)
y, (ft) V, (ft/sec)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
0.00 0.82 1.61 2.33 2.97 3.95 4.92 5.90 6.88 7.39 7.87 8.32 8.72 11.68 14.65 18.67 19.72 20.77 21.82
5.90 5.82 5.58 5.19 4.67 3.69 2.72 1.74 0.76 0.44 0.20 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00
0.73 0.64 0.57 0.55 0.57 0.49 0.45 0.42 0.39 0.39 0.33 0.29 0.27 0.28 0.29 0.18 0.18 0.18 0.19
0.73 0.63 0.53 0.46 0.40 0.35 0.32 0.29 0.28 0.27 0.27 0.27 0.27 0.28 0.29 0.18 0.18 0.18 0.19
6.63 6.46 6.15 5.74 5.24 4.19 3.16 2.16 1.16 0.82 0.52 0.34 0.27 0.28 0.29 0.18 0.18 0.18 0.19
Channel Floor
Water Surface
4.27 5.36 7.00 8.72 10.47 12.78 14.59 16.12 17.45 17.86 18.04 18.10 18.04 17.26 16.53 15.70 15.41 15.13 14.85
Energy Grade Line
Sequent
5.00
Depth y2, (ft)
4.00 3.00 2.00 1.00 0.00 0
5
10
15
20
25
1.76 1.72 1.69 1.42 1.40 1.39 1.38
Sequent Depth
8.00 7.00
Elevation (ft)
6.00 5.00 4.00 3.00 2.00
Figure 6 Trench 2.0 Bed Characteristics and definitions for the trench of figure 6
1.00 0.00 0
5
10
15
20
25
Easy access to all wall areas with the water jet helps to facilitate removing grease. The jet must be close to the wall to be effective, so attach a nozzle to the end of a long tube to make a water "lance" that can reach to within a yard or so of the surface to be washed. Access hatches make washing possible, but they are a nuisance. A better solution is an inside walkway the full length of the wet well as shown in Figure 4, but the entire space must then be well-ventilated and the vented air treated, all of which results in additional cost. However, ventilation and treatment protects concrete from corrosion and does allow easy access (not readily
Distance from Control (ft)
Figure 5. Trench2.0. Flow along the trench at pump-down. From www.coe.montana.edu/ce/joelc/wetwell, available free on the internet.
Grease Grease accumulates on walls between high and low water levels and must be occasionally removed. It clings tightly to concrete and may have to be scraped off. It can be more readily washed off walls coated or lined with plastic with a water jet of about 25 to 30 gal/min at a nozzle Pitot pressure of about 90 lb/in.2. Although expensive, coating is well worth the cost. 6
but they are small, and the deleterious effect is not pronounced.
achieved otherwise) to the suction bells for clearing out trash or for other needs, so the walkway can be justified in many pumping stations.
Caveat 3. Elevation of last pump intake Pumps in confined trenches often lose prime when the suction bell submergence is less than D/2. So place the bell rim at least D/2 below the sequent depth (given in Figure 5), and drop the floor under it to give a floor clearance of D/4. At greater floor clearances, larger grit and small stones may not be picked up by inlet velocities around 4 ft/s. ANSI/I 9.8 allows inlet velocities between 3 and 8 ft/s with a recommendation of 5.5 ft/s for medium-size pumping stations. One manufacturer designs solids handling column pumps for 3.5 to about 5 ft/s, and the authors recommend these lower velocities to prevent large, heavy trash such as parts of bricks or concrete blocks from being sucked into the pump and damaging it. (Include a rock trap upstream or just remove large, heavy trash manually from the trench as necessary.) Submersible pumps are designed for very high inlet velocities; so if the last pump is a submersible, add a suction nozzle with a flare to reduce the inlet velocity to 5 ft/s or less.
CAVEATS There are some caveats that must be heeded for a trench-type wet well to be completely successful. Caveat 1. Flow Splitter on Ramp To retain the energy developed by the ramp and to obtain a swift flow of water along the floor during cleaning (as in Figure 5), the flow splitter must begin at the top of the ramp and continue without interruption to some point between the last two pumps. (See the section entitled "Model" for an extensive discussion of flow splitters.) At super-critical velocities, any type of obstruction saps energy, may send a jet of water flying, and certainly reduces cleaning capability. If the flow splitter begins at the base of the ramp, the water--now at very high velocity--strikes this obstruction, jumps off the floor, probably impacts the first pump bell, loses nearly all of its energy, and never regains it. Quick cleaning is prevented. The trench can still be cleaned, but now it is by turbulence and attrition only. That process is slow, and the pump must run for many minutes under severe conditions As with flow splitters, the fillets also must begin at the top of the ramp. They should extend to the back wall to prevent the formation of sidewall vortices at the last pump.
Caveat 4. Cone Under Last Pump Because the last pump has a floor clearance of only D/4 (so as to scour grit effectively) and any flow splitter must clear the rim by 3 in. to pass solids, there is not enough room for an effective flow splitter in moderate-size pumping stations. Consequently, a cone under the last suction bell is a logical substitute for the flow splitter. See Figure 7. During pump-down for cleaning, water has a strong tendency to circulate between the last pump and the end wall. That circulation results in an upstream current on one side of the trench that keeps the hydraulic jump far upstream. The circulation can be so strong that it can go under the suction bell (even though the pump is running) and travel upstream. To prevent this
Caveat 2. Water Guide If the water from the inlet pipe is allowed to spread wider than the trench itself, some of it runs up on the sloping wall above the trench, where it slows and then falls back into the main stream at low velocity and disrupts the main flow. To prevent this occurrence, raise the sides of the trench near the top of the ramp to form a "water guide" that keeps all the water confined to the width of the trench. Water may run up on the fillets, 7
into the bottom of a ramp largely destroyed the energy of the flowing water and caused downstream flow to become sub-critical, a machinist at Montana State University suggested making the curved portions of flow splitters and fillets of a two-component casting compound [6]. The one chosen is very strong but flexible. Pour a slight excess into a wooden mold coated with floor wax. If the nose is gently tapered, one end of the mold can be suitably tapered to form a continuous nose. As soon as the compound cures enough to allow it, trim off the excess with a sharp knife. After final cure, warm the flow splitter with a bathroom heater and bend it over curves cut into wood with a band saw. The compound takes a permanent set upon cooling, but it does relax a little, so make the curves a little (say, 10 percent) sharper than the ramp curves. Fasten the pieces to the ramp with rubber cement, or screws, or both. Straight sections of fillets and flow splitters can be more easily made of wood well painted to resist moisture change and warping. With model flow splitter and fillets installed all the way up the ramp, the improvement in cleaning was dramatic. Velocities were very high and held up well to the end of the trench. But when the flow splitter was changed to end at the toe of the ramp, the energy and high velocity were destroyed. The downstream flow was turbulent but of sub-critical velocity that would not scour quickly. There is just no comparison between the performances of the two designs. Therefore, both flow splitter and fillets must extend to the top of the ramp for adequate cleaning potential.
occurrence, a fore-and-aft vane on the cone is needed as shown in Figure 7. a) 3" min (Notch apex of flow splitter if needed for 3" clearance under bell rim) Flow 2.5D Min 0.75D splitter Water surface See D sequent depth note a) Anti-rotation baffles 0.5D 0.38D Vanes Cone
0.25D
Figure 7. Construction at last pump intake.
Caveat 5. Anti-Rotation Baffle The tendency of water to circulate behind the last pump has been described in Caveat 4. To complete the suppression of flow between pump and end wall, an antirotation baffle (or barrier) is also required. Allow a minimum of construction clearance between the pump column and the baffle, but note that column pumps move slightly when pumping. Consult the manufacturer to find how much to allow for that movement. Caveat 6. End Wall During normal pumping, the stagnant water behind the last pump tends to form a surface vortex. Such vortices take the form of the letter "J". If the wall is moved close to the pump (ANSI/HI 9.8 recommends 0.75 D from the pump centerline), it intersects the "J" and the vortex does not organize. Sloping back walls outward allows the creation of a vortex. FORMING FLOW SPLITTERS AND FILLETS In the early stages of development, there were problems of how to design a flow splitter or fillets on a curving ramp--at that time not an easy task with either models or prototypes.
Other Means of Fabricating Model Flow Splitters and Fillets. Although casting compound is by far the most satisfactory material when installed, its use is involved and time-consuming. One way is to make the flow splitter and fillets entirely of wood. Cut it into thin cross-sections over curves, and set the sections in bathtub caulking compound such as Dap. After the
Models After a model test in a commercial laboratory showed that a flow splitter merging 8
cut with tin snips. These are glued to the plastic strip with Dap or super glue at intervals of three to six inches as appropriate. These are illustrated in Figure 8. Plastic sheets (for models and steel plates for prototypes) over ramp curves must be cut to the proper curvature. If the ramp curve has a radius of r, the formula for the radius, R, of a flat sheet to fit it is
Dap cures, coat the entire unit with Dap to waterproof it and fill the cracks. The result is ugly and rough but reasonably quick and easy.
R = r/Sinα, equation 1, where α is the angle between ramp and sheet. Flow Splitter Noses. A flow splitter must have some kind of nose. One of the easiest to make and best in performance tapers linearly from full size where it joins the prismatic flow splitter to zero at the top of the ramp. If β is the angle between the centerline of the ramp and the contact between nose and ramp (see Plan in Figure 9), the formula for the radius of curvature becomes
(a). Background: fillet of casting compound. Middle: 1D long (α =63o, β ≈17o) flow splitter nose of segmented wood followed by thin plastic sheet with triangular spreaders. Foreground: thin plastic sheet on supports of balsa wood triangles.
R = r/(Sin α Cos β), equation 2 The nose of a flow splitter separates 1.96D the Plan, developed incoming A flow into two A 45° streams B 1.96D that must have B R = 2.5D enough Longitudinal section depth and velocity max = 63.4° everywher preferred = 45° Section B-B Section A-A e to wash Figure 9. An excellent flow splitter nose debris off the ramp. Tests of inflow from horizontal pipe (low fluid velocity) and from approach pipe (high fluid velocity) were made at flow rates of 50 and 75 percent of the last pump's capacity. The best of several noses tried is shown in Figures 8(b) and 9. The apex angle (2 α ) is constant and
(b). 2D long (α =45 o, β ≈11 o) flow splitter nose of plastic sheet fastened with duct tape. Figure 8. Construction of model fillets and flow splitters.
One quick, easy way is to make flow splitter and fillets of thin (40 mil) plastic. It can be cut with tin snips and has about the right amount of stiffness. The strips for a flow splitter can be joined at the apex and to the floor with either Dap or long, narrow strips of duct tape pressed down firmly. Supports for fillets can be triangular pieces of plastic or thin (1/8 in.) balsa wood, which can also be 9
316L, or 347. Straight sections can be bent as shown in Figure 11a and held by 5/8- in. anchors either cast in the concrete or set in two-component adhesive in drilled holes. Alternatively, the construction shown in Figure 11b can be used. Along ramp curves, the plates must be cut to the radii given in Equation 1 (or 2 for noses), and then they must be flexed and stitch-welded at the apex. Either the type of construction in Figure 11b can be used, or the detail in Figure 11a can be followed if the plates are cut off a little below the floor and tabs are fastened to them for the bolts.
the nose height tapers linearly over a length of approximately 2D from the bottom of the upper ramp curve to the top of the ramp. A very long (4.3 D) nose was very good, and a very short (D long) one was adequate. Other Model Materials. Still another way is to cut fillets and flow splitters from plastic foam with a knife, table saw, or band saw, bend them to follow the contour of the ramp, and fasten them with rubber cement or even duct tape. One suitable material is Ethafoam [7], a polystyrene closed-cell, relatively rigid, strong foam. It holds a curvature if warmed and bent while cooling.
Alternate: bend plate at 3/8" radius
Choice. If the model floor can be removed for convenience in constructing fillets and flow splitters, the use of thin plastic sheet material is as easy and quick as any method. If not, the use of foam on ramp curves and either foam or wood for straight sections is easier. Either kind of flow splitters and fillets is easy to remove and replace--an advantage for demonstrating their value.
1-1/2" holes at 4'-0" C-C for pumpcrete
1/4" Type 304L S.S. Pumpcrete fill
Epoxy grout
2" 5/8" S.S.bolt x 8" at 12" C-C a. Detail for flow splitter straight sections
Prototype Fillets and Flow splitters Prototype fillets are easily made with shotcrete anchored into the corners with dowels (and with a rebar or two running the full length), screeded, and troweled smooth. If greater smoothness is needed as in long wet wells, coat the concrete with epoxy or line it with PVC. See Figure 10.
63.4°< 2"
3/4"x 4" (or as required by ogee curve) type 304L S.S. plate, at 2'-0" C-C max
Pumpcrete fill
<45°
3/16"
3/4" dia x 9" S.S. headed studs
b. Detail for flow splitter on ramp curves
2D Practically D 0.12D the only load max on flow Fillet splitters is #4 Rebar 0.5D during Dowel construction 45° when the Shotcrete 0.38D min Screed and trowel pumpcrete Figure 10. Prototype fillets can exert a pressure of 1 or 2 lb/in.2, so fastenings are needed primarily to hold the shape. Flow splitters can be made of 1/4-in. or even (for very large ones) of 3/8-in. stainless steel (ss) plate Type 304L,
Figure 11. Flow splitter for 18 Mgal/d wet well. After concepts developed by Brown and Caldwell.
The optimum slope for the sides of flow splitters is 45 degrees, but if the trench is narrow and the width of the floor too confining, steeper slopes (up to 2:1 = 63.4o) are acceptable. In the 18 Mgal/d pumping station example, a flow splitter with sides sloping 45 degrees leaves floors only 6 in. wide, whereas a 2:1 slope provides floors 11 in. wide. It is designer's choice. For the detail in Figure 11b, specify that on ramp curves the contractor shall (before cutting expensive stainless steel) 10
electronic form. The authors express their gratitude to all those who contributed.
make wood patterns of the flow splitter (and its nose) of thin (1/8 to 1/4- in.) plywood, transport them to the field, and scribe accurate offset lines on them so that the steel sheets follow all the imperfections of the concrete surface. The cost of flow splitters varies greatly with contractor and circumstance, but a budget figure today is about $550/linear ft for the flow splitter in Figure 11b--mostly for labor. It may cost more on the ramp. The flow splitter in Figure 11a is probably less expensive.
LIST OF REFERENCES 1. ANSI/HI 9.8-2007. American National Standard for Pump Intake Design, Hydraulic Institute, Parsippany, NJ (scheduled for publication in 2008). 2. Sanks, R.L., G. Tchobanoglous, B.E. Bosserman, and G.M. Jones. Pumping Station Design, 2cd Ed., ButterworthHeineman, Boston (1998).
CONCLUSION A trench-type wet well built to the recommendations of the American National Standard for Pump Intake Design [1] augmented by the advice herein is a superb performer and needs no improvement. Model study is, however, required if a pump exceeds a capacity of 40,000 gal/min, if the station capacity exceeds 100,000 gal/min, if pump operation and reliability is exceedingly critical, if approach flow is non-uniform or asymmetric, or if the geometry of Figure 1 is altered.
3. G.M. Jones, R.L. Sanks, G. Tchobanoglous, B.E. Bosserman. Pumping Station Design, 3rd Ed., Elsevier, Boston (2006). 4. Trench2.0. A user-friendly computer program developed by Prof. Joel Cahoon, to calculate water depths, velocity, Froude numbers, and sequent depths along the trench in trenchtype wet wells. Available free at www.coe.montana.edu/ce/joelc/wetwell. 5. UnifCrit2.2. A user-friendly computer program developed by Prof. Joel Cahoon to calculate flow rate, velocities, water depths, and critical water depth in circular and trapezoidal open conduits. Available free at www.coe.montana.edu/ce/joelc/wetwell.
ACKNOWLEDGEMENTS This paper was sent to all commercial laboratories that test hydraulic models of pumping station wet wells. The correspondents were Thomas Demlow of Northwest Hydraulic Consultants, Inc., Andrew E. Johansson of Alden Research Laboratory, Richard E. Long of ENSR, and Tatsuaki Nakato, recently retired from the University of Iowa. There were suggestions for additions and word changes but no disagreements. Other reviewers were Garr M. Jones and Lawrence Oeth of Brown and Caldwell, Arnold Sdano of Fairbanks Morse Pump – Pentair Water., Sateesh Nabar of Nabor Stanley Brown, Inc., Sarwan Wason and Mike Zappone of Carollo Engineers, Constantino Senon of MWH Americas, and William Wheeler of Wheeler Designs. Arnold Sdano converted the penciled figures into
6. Obtainable from McMaster-Carr Supply Co., Santa Fe Springs, CA. (www.mcmaster.com) as two-part casting compound No. 8644K11 for 1 lb (25 in3) or as No 8644K12 for 10 lb (250 in3). 7. Obtainable from many sources including McMaster-Carr Supply Co. as Item No. 86155K33.
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ATTACHMENT D COMPUTATIONAL FLUID DYNAMIC MODELING OF A PROPOSED INFLUENT PUMP STATION
By Edward Wicklein, Charles Sweeney, Constantino Senon, Doug Hattersley, Brian Schultz and Randy Naef
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Computation Fluid Dynamic Modeling of a Proposed Influent Pump Station Edward Wicklein, Charles Sweeney, Constantino Senon1, Doug Hattersley1, Brian Schultz1, and Randy Naef 2 ENSR 9521 Willows Road NE Redmond, WA 98053 1) MWH Americas, 2) Clean Water Services ABSTRACT Traditionally pump intake hydraulics have been investigated using scale physical hydraulic models. Computational fluid dynamics (CFD) is a rapidly improving technology that in some cases can be used as a cost or time effective alternative to traditional physical model methods for evaluation of pump intake hydraulics. This paper presents a case study on the use of CFD modeling to re-evaluate and modify the design of a large wastewater treatment plant influent pump station. The pump station has two a self cleaning trench wet wells, which was physically modeled early in the design process. Changes were made to the pump station layout and capacity during subsequent facility design. A CFD model was used to refine the design of the wet wells and evaluate the effects of upstream sewer alignment on the pump hydraulics. This paper presents the results of the CFD model analysis and design refinement. KEYWORDS CFD modeling, Physical Modeling, Pump Intake Hydraulics, Wastewater INTRODUCTION A new wastewater treatment plant influent pump station is being designed and constructed as part of an overall wastewater treatment plant facility upgrade. The pump station has two parallel self cleaning trench wet wells with an initial pumping capacity of 180 mgd, and an ultimate capacity of 240 mgd. The parallel trench wet wells will be mirror images of each other, with the inside wall common to both wet wells and the pump and control rooms located on the outside of the wet wells. Pump stations of this size and type are typically evaluated with a scale physical model to investigate and verify the hydraulic conditions approaching the pumps. Early in the design process a scale physical hydraulic model study was conducted to improve the hydraulic performance of the proposed pump station (ENSR 1999). Through extensive model testing, a series of geometric modifications were developed to improve the hydraulic conditions. Subsequent analysis to reconcile station inflow rates led to several changes in the proposed pump station design. These changes included a reduction in flow rate leading to fewer required pumps, and a revised influent sewer design that simplifies construction. The design of the revised pump station was different enough from the previously modeled design that additional analysis was desired. An additional goal was to evaluate the effects of proposed upstream sewer changes on
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the pump hydraulics; therefore an innovative modeling approach was taken to aid in refining and verifying the hydraulic design of the proposed pump station utilizing a CFD model. POTENTIAL PUMP STATION HYDRAULIC PROBLEMS Hydraulic conditions have been identified such as air entrainment, vortex action, pre-swirl, and excessive turbulence in the approach flow to pumps can lead to fluctuating loads on pump impellers, vibration, cavitation, loss of pump capacity, and decreased efficiency (Sweeney and Rockwell 1982). It has been shown that these problems are strongly influenced by the approach flow hydraulics upstream from the pump, caused by the wet well geometry coupled with the influent conditions. Straight and uniform approach flow reduces the tendency for pump problems, whereas variable approach flow direction and non-uniform velocity distribution generate eddies and circulation patterns, which may adversely affect pump operation. Providing uniform approach flow conditions may reduce the potential for pre-swirl and vortex formation. Tullis (1979) and Sweeney et al. (1982) have documented repeated cases in which preclusion of submerged vortices has required the installation of anti-vortex devices such as flow splitters, guide vanes, and/or cones. The geometry of the wet well, operation of the pump(s), and depth of water in the sump influence the approach flow hydrodynamics and can result in the following adverse hydraulic phenomena (Sweeney and Rockwell 1982): •
pre-swirl of flow approaching the pump impeller;
•
free surface vortex formation;
•
submerged vortex formation;
•
spatial asymmetry of the flow approaching the pump impeller; and
•
temporal fluctuations (turbulence) in the flow approaching the pump impeller.
Pump impellers are designed with the assumption that flow approaches the impeller axially. Preswirl of the flow in a pump inlet causes the flow to approach the impeller at an angle, which can result in a change in pump performance (head and flow). Pre-swirl may also reduce the minimum pressure on the impeller blade if the direction of pre-swirl is opposite the direction of rotation of the impeller. Excessive low pressure on the suction side of the pump impeller blades may ultimately cause cavitation damage. In addition, if the pre-swirl is not constant, it will result in load fluctuations. Free surface vortices and submerged vortices can also influence pump operation. Strong free surface vortices may cause air to be entrained into the pump, potentially resulting in loss of prime and loss of pump capacity. Submerged and free surface vortices entering the pump, even without air entertainment, will impose a fluctuating load on the pump impeller blades as each blade passes through the lower pressure vortex core. Stable vortices produce load fluctuations at blade pass frequency (or multiples thereof) capable of causing vibration, accelerated bearing wear and, in extreme cases, impeller and diffuser component fatigue. If the natural frequency of
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the pump vibration approaches the blade pass frequency, destructive resonance results. The lowpressure vortex cores may reduce the local pressure at the impeller below the fluid pressure and induce cavitation of the impeller blades. Spatial asymmetry in the distribution of velocities around the pump may cause an unbalanced loading on the impeller and vibration, while temporal fluctuations (turbulence) in the velocities at a particular point may result in broad-spectrum noise and vibration. Deviations in the spatial and temporal velocity distributions also can produce cavitation. PUMP STATION HYDRAULIC ANALYSIS METHODS Traditionally, scale model studies have been conducted to optimize the design of large pump stations; however, an emerging technology for pump station analysis through CFD modeling. Applications of CFD models to simulate flow fields associated with pump intakes have been underway for several years. Reports and papers have been published on the use of CFD modeling for analysis of pump station hydraulics, including: Constantinescu and Patel (1998); Nagahara et al. (2001); Li et al. (2001); and Ansar et al. (2002). Much of this research has focused on the simulation of vortex formation in pump sumps and circulation for pump stations with a single operating pump. Wicklein et al. (2002) have shown that a CFD model can accurately reproduce the flow field associated with cooling water pump intakes with multiple bays for a range of pump operations and water levels. Wicklein and Rashid (2006) have demonstrated that CFD models are very valuable tools for investigating pump station hydraulics and developing modifications to address performance deficiencies. CFD Modeling Commercially available CFD models numerically solve the fundamental equations of fluid flow, conservation of mass and momentum, known as the Reynolds-averaged Navier-Stokes (RANS) equations. These equations do not form a closed set (ASCE Task Committee 1988), owing to the non-linearity of the original Navier-Stokes equations and their temporal averaging. Current CFD models solve additional equations representing the turbulence characteristics of a flow field, which is a key parameter in determining the nature of flow, eddy formation, circulation, flow separation, and flow interaction with structures. The turbulence models commonly used in hydraulic engineering have been reviewed by the ASCE Task Committee (1988) and Rodi (1980). Commercial CFD models offer various turbulence closure models, the most common of which are based on second order closures using k-ε and k-ω formulations. In their general form, RANS equations cannot be solved analytically. Commercial CFD models approximate the differential equations by the finite difference method which resolves the equations into a set of algebraic equations (Lomax et al. 2003). These algebraic equations are solved to provide hydraulic information (e.g., velocity, water surface elevation, and pressure) at a finite number of discrete points within the flow domain. Most finite difference-based CFD models use the finite volume method, as this approach allows the use of unstructured computational grids. As the RANS equations are typically solved by the finite difference method, it is necessary to discretize the flow domain into a computational grid to define the actual locations where
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equations of flow will be solved. Traditionally the individual computational cells are hexahedral (6 faces), pyramidal (5 faces), prismatic (5 faces) or tetrahedral (4 faces), defined by the corner vertices. The task of grid generation is accomplished through the use of grid generating software that allows for definition of the model geometry, computational cell size, and grid density, and provides tools for grid quality analysis. Unstructured computational grids are the most common type, as they allow the greatest flexibility in defining the model domain and meshing properties. The flow field computed by the CFD model is a direct function of the flow conditions applied at the domain boundaries, known as boundary conditions. Typical boundaries include inflow boundaries, outlet boundaries, pressure boundaries, symmetry boundaries, and wall boundaries. Inlet boundaries provide a constant velocity in the three vector components into or out of the model domain, as well as constant turbulence characteristics. Pressure boundaries have constant pressure and turbulence characteristics, and flow can move in or out of the domain. Outlet boundaries only allow flow to travel out of the domain, and have no pressure or turbulence constraints. Symmetry boundaries allow no vector component normal to the boundary. Wall boundaries are considered solid with no flow through the boundary. The wall boundary type can either be no slip, with a roughness component, or a slip wall with no roughness component. Typically the law of the wall function is used to approximate the transition from the zero velocity at the boundary through the boundary layer into the free stream, which models the effective drag from the roughness at the wall, without requiring the large number of computational elements required to resolve the flow field within the boundary layer. Typically the boundary layer is not resolved when investigating large scale flow features due to significant computational overhead requirements in resolving this flow feature. Model Performance Criteria The Hydraulic Institute (HI) established criteria for evaluating performance of pump station designs through the use of physical hydraulic model studies. The details of physical modeling procedures and results interpretation are explained in ANSI/HI 9.8-1998. The summarized minimum performance criteria for physical models are: •
No organized free surface and/or subsurface vortices of greater magnitude than a Type 2 shall enter the pump for Froude-scaled model operation (referring to HI 1998 Figure 9.8.23). Dye cores must not be coherent for more than 10 percent of the time.
•
The level of pre-swirl should be less than 5 degrees from axial and should be steady.
•
Time-averaged velocities measured at eight locations in the pump throat should be within ± 10 percent of the spatial mean of time-averaged velocities.
•
The temporal fluctuations of velocities measured at each of the eight locations should be less than 10 percent of the average measured at that location.
To date, a similar detailed set of performance criteria for evaluation of pump station performance using numerical model results has not been established by HI. The key difference between current CFD model results and the results from physical model studies is that physical models are run in a quasi-steady state, whereas CFD models are run in an Copyright ©2006 Water Environment Foundation. All Rights Reserved
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absolute steady state. A physical model has a fixed inflow, outflow, and average water level, but the velocity and water level at a given point fluctuate due to turbulence and local flow instabilities. Currently, CFD models provide the averaged solution of velocity at all points in the domain, and have a non-fluctuating water surface. The CFD model results therefore cannot be exactly compared with the current physical model criteria, as the fluctuating components of the flow field are averaged out. It was previously established that the physical model study conducted by ENSR developed a set of geometric changes that brought the pump station performance within established HI criteria for physical model testing. Therefore, analysis of the same station with a CFD model should produce model results that would similarly meet HI criteria. For comparison and presentation of pre-rotation and velocity results, point data were extracted from the CFD results in the pump suction piping to replicate the data taken from physical model. Eight points were taken on 45-degree increments on a radial traverse at the impeller elevation, and eight points were taken on similar 45-degree radial traverse at the point where a rotometer would be located in the physical model. The data taken at rotometer location were used to calculate a rotational velocity within the pump suction piping. The angle of flow rotation approaching the impeller, θ, is reported in degrees from axial, and typically referred to as pre-swirl. The angle is calculated by equation 1:
ș = Tan −1 (U t /U a )
(1)
where: Ut = tangential component of velocity Ua = axial component of velocity In this case the approach angle was calculated for each of the eight points, and averaged to find the average flow angle. For this study a positive angle indicates flow rotating clockwise looking downstream at the rotation location. The maximum and minimum velocity is found by dividing the velocity found at each of the eight points by the cross sectional average velocity. The velocity is then expressed as a nondimensional ratio, which facilitates comparison between different flow rates and scales. BASELINE CFD MODEL
A CFD model of the final design of the physically modeled pump station was developed. The physical model included two parallel straight influent conduits 40-prototype feet long and 6.75 feet wide by 7 feet high. The conduits ended at an ogee crest at the start of the wet well. The wet well contained 4 pumps. The capacity of the two upstream pumps was 45 million gallons per day (mgd) each, and capacity of the two downstream pumps was 30 mgd each. The pump suction piping included a short radius flared turndown elbow, a horizontal spool, an eccentric reducer, and a long radius reducing elbow which ended at the pump flange. The wet well width
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was narrowed through several transitions from the upstream end to the downstream end. A fillet ran the length of the wet well between the walls and floor. A center triangular cross section flow splitter also ran the length of the wet well. A horizontal baffle blocked the top portion of flow on the centerline of the inflow jet to better distribute flow in the wet well. The CFD model geometry was developed from the CAD drawings of the final modified wet well design reported by ENSR (1999). The drawings were in two dimensions and at the model scale of 1:4.8. They were scaled to project dimensions, and the three-dimensional geometry was developed from the files. Figure 1 shows and isometric view of the model grid of the physically modeled wet well configuration. The model grid is made up of over 567,000 hexahedral (6 faces) and prismatic (5 faces) cells. The grid is sufficiently refined to include a 1.2-inch thick wall on all pump piping within the wet well. Figure 1 - Baseline Model Grid
Baseline Test Program
The CFD model was run for 5 different flow rates/pump operating conditions that were run in the physical model. Table 1 summarizes the tests run, and the corresponding physical model documentation test numbers.Table 1 – Baseline Pump Operating Conditions Test No.
Water Surface Elevation (ft)
Pump Flow (mgd) Pump 1
Station Flow (mgd)
Pump 2 Pump 3 Pump 4 1 92.2 45 45 2 93.3 45 30 75 3 93.6 45 45 90 4 94.5 45 45 30 120 5 95.6 45 45 30 30 150 The tests chosen represented the range of operating flows, pump operations and water levels tested in the physical model. In addition, tests were chosen that included operation of pump 2, Copyright ©2006 Water Environment Foundation. All Rights Reserved
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which had the most detailed instrumentation in the physical model. In all cases the CFD model was run to a converged steady state solution, defined for this project as a global residual of key computed values of less than or equal to 0.001. Baseline Run Model Results
The results of the CFD model runs were compared with the physical model results using the typical parameters that are used to present physical model results: pre-swirl, and the maximum and minimum velocity at the impeller location. The tabular results of point data locations from the CFD model are compared with the physical model results for all 5 tests in Table 2. Results are reported from all pumps operating in the CFD model. Velocity information is only reported from pump 2 in the physical model as this was the only pump with an instrument to record velocity data. The velocity information was included for all pumps in the CFD model, as it was readily available. Table 2 – Baseline Model Result Comparisons Between CFD Model and Physical Model Test No. 1 2
3 4
5
Pump
2 2 3 1 2 1 2 3 1 2 3 4
Degrees from Axial CFD Physical -5.3 0.7 -2.1 0.6 0.4 0.7 0.4 1.1 -1.1 -1.2 0.6 2.8 -4.6 1.7 4.6 -0.2 0.9 1.6 -6.9 0.5 4.5 -3.4 4.5 0.8
Vmin/Vavg CFD Physical 0.97 0.98 0.97 0.99 0.95 0.97 0.96 0.97 0.97 0.97 0.98 0.95 0.95 0.97 0.97 0.95 0.97
Vmax/Vavg CFD Physical 1.03 1.05 1.02 1.04 1.04 1.03 1.03 1.03 1.03 1.03 1.03 1.04 1.03 1.03 1.04 1.04 1.03
The pre-swirl of flow approaching the impeller is typically higher in the CFD results for most of the cases. This is not surprising, as the means of calculating the angle is slightly different for the two models. In the physical model the tangential velocity is measured by a rotometer for a fixed amount of time, which is assumed to be representative of the flow field. Because of flow instability, the tangential velocity is not steady and can reverse direction during a course of measurement. In this case the reversal reduces the average, leading to a lower reported value. This type of flow instability is very common in trench wet wells with a strong inflow jet. Review of the complete data from the physical model testing reveals that for very similar operations with minor or no geometric changes, the angle reported could be either positive or negative. The CFD results represent a true average condition. The established criterion for the
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approach angle is 5 degrees from axial. The CFD model results show that this criterion is met in almost all of the cases, as it had been in the physical model study. Both the maximum and minimum velocity compare very well between the CFD model and the physical model. In both cases the velocity is nearly uniform at the impeller location. This uniformity is expected, as the piping has both an eccentric reducer and a long radius reducing elbow with a 61 percent area reduction. Flow acceleration attenuates velocity profile variations. Figure 2 shows three views of the velocity magnitude in the wet well for test condition 1. The top image shows the velocity magnitude at the water surface, which is generally symmetric along the centerline. The middle image shows a section view through pump 2, the only operating pump in this condition. The velocity is generally low in the top portion of the wet well, and higher near the pump inlet. There is considerable flow separation within the flared suction elbow in, as evident by the low velocity region on the downstream side of the elbow. The bottom image shows a vertical section view along the wet well centerline. The flow dives below the baffle location, to the operating pump, and the velocity is generally low in the rest of the wet well. Figure 3 shows streamtraces through the wet well. Flow enters the wet well, and dives below the baffle, setting up two vertical circulations. Flow moves up the ogee, where it is reentrained in the inflow jet. A second circulation cell develops in the downstream end of the wet well, with flow moving toward the baffle near the surface, and then being pulled down at the baffle location. In general, we can conclude that the CFD model results compare reasonably well with the physical model results, and the CFD model is therefore representative of the system. As the physical model and the CFD model of the same configuration met established performance criteria, we assumed subsequent CFD model runs should similarly be held to the same performance standards.
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Figure 2 – Three Views of the Initial Flow Field, Test 1
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Figure 3 – Streamtraces of Flow Path For Initial Flow Field, Test 1
REVISED WET WELL CFD MODEL
The pump station design was modified to account for a new flow capacity, geometric changes to the influent sewer, and a new pump phase-in program. The phase 1 maximum pump station capacity will be 180 mgd, or 90 mgd per wet well. The wet wells were moved adjacent to each other with so that separate pump mechanical rooms could be located on the outside of the station. The first two pumps in each side of the station will have a capacity of 25 mgd, and the last pump will have a capacity of 40 mgd. The piping through the wall and in the wet well will be 42 inches in diameter for all pumps so that a future capacity expansion can be carried out without the need to replace piping within the wet well. All pipe fittings used were standard ductile iron. The wet well was shortened by 9 feet and the three pumps located on 15-foot centers. The invert of the ogee crest was raised to an elevation of 92.15 feet, and the entire wet well elevation was adjusted to account for the change in ogee elevation. The box culvert at the influent was replaced with a 72-inch diameter pipe that enters a 36 foot long transition section, which ends at the ogee. The model was revised to reflect the new pump station geometry, which included raising and shortening the wet well, replacing the pump piping, and modifying the upstream sewer system. The model grid depicted in Figure 4 shows an isometric internal view of the wet well and suction piping.
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Figure 4 - Revised Model Grid
Revised Model Test and Results
The new wet well will operate at different flow rates, water levels, and pump operations than the previous physical model. One test was carried out with the new design. For this test pumps 1 and 2 operated at 25 mgd each, and the water level was set to maintain critical flow depth at the ogee crest. At wet well water levels below the critical depth at the ogee for the given flow, the pumps will pump down the wet well and the condition therefore couldn’t be maintained. The test results are summarized in Table 3 Table 3 – Revised CFD Model Initial Results
Pump
Discharge (mgd)
1 2
25 25
Water Level (ft)
Degrees from Axial
Vmin/Vavg
Vmax/Vavg
5.87 -6.54
0.97 0.95
1.03 1.04
94.51
With the revised pumps, the velocity distribution at the pump impeller location was not changed significantly from baseline results. The pre-swirl increased significantly in the two operating pumps, as compared with the initial tests. Figure 5 shows contours of velocity magnitude for the run, similar to the previous Figure 2. The flow field in the wet well was driven by the strong inflow jet from the 72-inch diameter pipe. Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Replacing the inflow box culvert with a pipe significantly reduced the flow area, and lead to a corresponding increase in flow velocity entering the wet well. The expansion transition from the circular pipe to the wet well did not significantly dissipate the inflow jet energy. The jet attached to the wall adjacent to the pump mechanical room. The top of the horizontal baffle extended above the water surface, which forced the jet to dive toward the first two operating pumps. Significant flow separation was evident at the inside bend of the flared suction elbow in pump 2. In addition, it appeared that much of the flow entering the elbow was coming from the right side of the center floor flow splitter which contributes to pre-swirl. Figure 6 shows streamtraces colored by velocity magnitude within the wet well. A recirculation zone developed in a portion of the expansion, adjacent to the jet after it attached to the wall. Flow dove beneath the baffle and reached the floor near pump 2. From there flow traveled along the floor and rose at the downstream end of the wet well. The flow then traveled upstream at the wet well surface to the baffle wall, where it was pulled down to pump 1. There was swirling of flow between pumps 2 and 3. DESIGN DEVELOPMENT TESTING
Extensive changes were made to the wet well design through a series of tests. These changes addressed the excessive pre-swirl of flow, reduced the flow separation in the suction piping and reduced the tendency for surface vortices to develop. Figure 7 shows typical coherent flow swirl from the surface that reached the pumps. Modifications included replacing the suction elbows with long radius elbows and flares to reduce the observed flow separation. This change necessitated lowering the wet well floor elevation, which reduced the tendency for the surface swirl develop and reach the pump inlet locations. The wet well was shortened and the water levels were raised above critical depth at the ogee. Finally, non-clog anti-rotation vanes were added in the suction piping to reduce pre-swirl of flow approaching the pumps. The vanes significantly reduced pre-rotation of flow approaching the pumps. The wet wells still included the fillets and center flow splitter developed in the previous physical hydraulic model study that were necessary to minimize development of submerged vortices, and aid in the self cleaning cycle. The final model grid is shown in Figure 8.
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Figure 5 – Three Views of the Revised Model Flow Field
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Figure – 6: Baseline Results
Figure 7 – Typical Surface Swirl Reaching the Pump Suction Inlets
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Figure 8 - Final Model Grid
FINAL MODEL RUNS
A series of documentation tests were run with the final model to verify the pump station performance for a range of pump operations. The test program used for documentation testing is presented in Table 4. The wet well water level was set based on the normal depth of flow where the 72-inch diameter influent entered the wet well transition section. Only one wet well was modeled in detail for these operations. Table 4 – Pump Station Documentation Tests Operations Pump Flow (mgd)
Test No.
Pump 1
Pump 2
Pump 3
Total Station Flow (mgd)
1 2 3
0 25 25
25 25 25
0 0 40
25 100 155
Minimum Operating Water El 94.30 95.30 96.90
Three tests were run documenting the flow conditions in the wet well for phase 1. The results of the three tests are summarized in Table 5. For these tests the pre-swirl was very low, with a peak computed value of 2.6 degrees which was less than the peak value calculated for the physical model configuration of 6.9 degrees. The velocity distribution was almost uniform, with only slight variations.
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Table 5 – Documentation Tests Results
Test No. 1
Pump 2
2
1 2 1 2 3
3
Discharge (mgd) 25 25 25 25 25 40
Water Level (ft) 94.30 95.30
96.9
Degrees from Axial 1.3 2.6 2.3 1.0 0.4 0.7
Vmin/Vavg 0.99 0.98 0.99 0.98 0.98 0.96
Vmax/Vavg 1.01 1.01 1.01 1.01 1.01 1.04
Figures 9 through 11 show the results of the runs. The figures all show the wet well surface velocity magnitude, the velocity magnitude at a centerline section through the wet well, and a section through pump 2. The results of all three tests were well within the performance criteria established previously during analysis of the physical model. SUMMARY AND CONCULSIONS
The wet well hydraulics of an influent pump station were investigated with a CFD model for the original recommended sump design developed through a physical model study. Performance criteria for evaluating the CFD model were established through comparison of the CFD results with the physical model study results. The CFD model was then used to evaluate the proposed system changes. The flow details at the pump impeller location were very dependent on the suction piping. The tendency for surface vortex formation was dependent on the wet well geometry. Modification tests were conducted that led to a wet well design that decreased the potential for vortices to develop, improved the velocity distribution, reduced flow separation in suction elbows, and reduced pre-swirl of flow to acceptable levels for a wide range of operating conditions. The model was also used to aid in design of an upstream sewer junction. The model was used again after the studies reported on in this paper closer to the time of field construction to evaluate the effects of changes in the sewer design geometry on the hydraulic conditions at the pump suction locations. This proved to be a great advantage over traditional physical model methods as the upstream sewer is seldom included in the physical model, and the physical model is seldom kept until field construction is completed. The CFD model is digital, and is available for use at any time after it is developed. Further, the modeling is conducted at prototype scale with fewer practical restrictions on the overall domain of the model.
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Figure 9 – Three Views of the Final Model Flow Field, Test 1
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Figure 10 – Three Views of the Final Model Flow Field, Test 2
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Figure 11 – Three Views of the Final Model Flow Field, Test 3
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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REFERENCES
Ansar, M., T. Nakato, and G. Constantinescu. 2002. Numerical Simulations of Inviscid ThreeDimensional Flow at Single-and Duel-Pump Intakes. Journal of Hydraulic Research, 40(4), pp. 461-470. ASCE Task Committee. 1998. Turbulence Modeling of Surface Water Flow and Transport: Part I, II, III, IV, V, Task Committee on Turbulence Models in Hydraulic Computations. Journal of Hydraulic Engineering, 114(9), pp. 970-1073. Computational Dynamics Ltd., 2002a, Methodology, STAR-CD Version 3.15, Computational Dynamics Ltd. London, U.K. Computational Dynamics Ltd., 2002b, User Guide, STAR-CD Version 3.15, Computational Dynamics Ltd. London, U.K. Constantinescu, G. S., and V. C. Patel. 1998. Numerical Model for Simulation of Pump-Intake Flow and Vortices. Journal of Hydraulic Engineering, 124(2), pp. 123-134. ENSR. 1999. Final Report, Durham Wastewater Treatment Plant 3 Expansion Influent Pump Station Hydraulic Model Study. Prepared for HDR Engineering, Portland, Oregon. E. Wicklein, and M. Rashid. Use of Computational Fluid Dynamic Modeling to Evaluate Pump Intake Performance and Develop Design Modifications. Published in the Proceedings of the 2006 ASCE Environmental Water Resources Conference, Omaha, Nebraska, May 2006 Hydraulic Institute. 1998. American National Standard for Pump Intake Design. ANSI/HI 9.81998. Li, S., L. Yong, J. Silva, and V. C. Patel. 2001. CFD Modeling of Three-Dimensional Flow in Practical Water-Pump Intakes. IIHR Technical Report No. 419. Lomax, H., T. Pulliam, and D. Zingg. 2003. Fundamentals of Computational Fluid Dynamics, Springer, Berlin, Germany. Nagahara, T., T. Sato, and T. Okamura. 2001. Effect of the Submerged Vortex Cavitation Occurred in Pump Suction Intake on Hydraulic Forces of Mixed Flow Pump Impeller. Presented at CAV 2001: Fourth International Symposium on Cavitation, California Institute of Technology, Pasadena, CA USA. June 20-23. Rodi, W., 1980. Turbulence Models and their Application in Hydraulic Models. International Association for Hydraulic Research, Delft, The Netherlands. Sweeney, C.E., D. Hay, and R.A. Elder. 1982. Pump Sump Design Experience: Summary. Journal of Hydraulic Division, A.S.C.E. Vol. 108, No. HY3: pp. 361-78.
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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Sweeney, C.E., and G.E. Rockwell. 1982. Pump Sump Design Acceptance Through Hydraulic Model Testing. 11 pp. In: Proc. of the International Association for Hydraulic Research: Symposium on Operating Problems of Pump Stations and Power Plants. Amsterdam, The Netherlands, 13-17 September 1982. Tullis, J.P. 1979. Modeling in Design of Pumping Pits. Journal of Hydraulics Division, A.S.C.E. Vol. 105, No. HY9: pp. 1053-63. Wicklein, E., C. Allaben, and M. Rashid. 2002. Optimizing Cooling Tower Pump Intakes Using Computational Fluid Dynamics Models. Published in the Proceedings of the 2002 Industrial Water Conference, Orlando, Florida.
Copyright ©2006 Water Environment Foundation. All Rights Reserved
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ATTACHMENT E DESIGN WORKSHEETS
This page left intentionally blank
Appendix E.1 Fluid Properties CALCULATIONS Client: (Client Name Here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Description:
Job No:
Summary of Fluid Properties
By:
(Author)
(Enter Job Number) Chkd By:
Fluid Properties The design engineer shall complete the following table with all relavent information.
Fluid type Temperature Specific Gravity / Density Vapor Pressure Kinematic Viscostity Solids Content Sphere Size pH Corrosivity
Circle in Not Applicable N/A N/A N/A N/A N/A N/A N/A N/A N/A
Properties of Water
Calculations Page 1 of 11
PF - 6.6.#
Appendix E.2 Physical Properties of Water CALCULATIONS Client: (Client Name Here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Description:
Summary of Fluid Properties
Job No: By:
(Author)
(Enter Job Number) Chkd By:
Physical Properties of Water
Calculations Page 2 of 11
PF - 6.6.#
Appendix E.3 Operating Envelop Worksheet CALCULATIONS Client: (Client Name Here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Description:
Definition of Pump Station Operating Envelope
Job No: By:
(Author)
(Enter Job Number) Chkd By:
Operating Conditions The design of the pumping system must take into account the range of flows that the facility will be expected to accommodate over the life of the project. The minimum, average, and peak flows for both current and future conditions should be established to characterize the range of flow conditions. The diurnal varations in water demand and wastewater flow are typically important for the design of related pumping facilities. In most cases it is important to characterize weekly, monthly or seasonal differences Minimum Daily Flow Average Daily Flow maximum Daily Flow
MGD MGD MGD
Client Provided Information [ Paste any Client Provided Flow Information }
Calculations Page 3 of 11
PF - 6.6.#
Appendix E.4.1 Suction Configuration Worksheet CALCULATIONS Client: (Client Name Here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Description:
Preliminary Suction Configuration Calculations
Job No:
(Enter Job Number)
(Author)
By:
Chkd By:
Wet Well Design [HAND DRAWN SKETCH OF PIPING LAYOUT]
Horizontal End Suction or Horizontal Split Case Suction Pipe Diameter D= in
Calculations Page 4 of 11
Straight Run of Pipe X=
in
L1 =
in
L2 =
in
D1 =
in
D2 =
in
PF - 6.6.#
Appendix E.4.2 Suction Configuration Worksheet CALCULATIONS Client: (Client Name Here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Description:
Preliminary Suction Configuration Calculations
Job No: (Author)
By:
(Enter Job Number) Chkd By:
Wet Well Design Hydraulic Institute Type of Wet Well Dimensions D= B= w= W= X= a= Z= H= h= S= C=
in in in in in in in in in in in
[HAND DRAWN SKETCH OF PIPING LAYOUT]
Notes : 1. 2. 3. 4. 5. 6. Calculations Page 5 of 11
PF - 6.6.#
Appendix A.5.2 Suction Configuration Worksheet CALCULATIONS Client: (Client Name Here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Description:
Preliminary Suction Configuration Calculations
Job No: (Author)
By:
(Enter Job Number) Chkd By:
Wet Well Design Flygt Large Submersible Pump Station Design A= B= C= D= E= F=
in in in in in in
Note: For additional wet well design information, see Flygt Design Guide.
[HAND DRAWN SKETCH OF PIPING LAYOUT]
Notes : 1. 2.
Calculations Page 6 of 11
PF - 6.6.#
Appendix E.4.3 Suction Configuration Worksheet CALCULATIONS Client: (Client Name Here)
Sheet:
Project: (Project Name Here) Description:
Date: Job No:
Preliminary Pump Barrel Configuration Calculations
(Author)
By:
of mm/dd/yy (Enter Job Number) Chkd By:
Wet Well Design Vertical Turbine Can Pump Installation
D= D1 = X= H=
X
in in in in
Y
H (H>4D) X Y H (H>3D)
X = 5 times Pipe Diameter D = Bell O.D. H = 3 to 4 times D (MWH exception to HI) 0 time Y = The min HGL shall be 1 1.0 the pump barrel diameter above the centerline of the suction piping.
[HAND DRAWN SKETCH OF PIPING LAYOUT]
Calculations Page 7 of 11
PF - 6.6.#
Appendix E.4.4 Suction Configuration Worksheet
CALCULATIONS
Client: (Client Name Here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Description:
Preliminary Suction Configuration Calculations
Job No: (Author)
By:
(Enter Job Number) Chkd By:
Wet Well Design Self Cleaning Wet Well D= W= B= S=
in in in in
4D min
Exception: 1. Submergence S is great than or equal to 4 times the pump bell diameter. (MWH exception to the HI standard based on model study from Durham and Tacoma Pump Station 2. See Pump Station Design Guide section on Self Cleaning Wet Wells. Calculations Page 8 of 11
PF - 6.6.#
Appendix E.5.1 NPSH Worksheet for Vertical Turbine Pumps CALCULATIONS Client: (Client Name Here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Description:
Job No:
Preliminary NPSH Calculations
By:
(Author)
(Enter Job Number) Chkd By:
Header (edit ) The following calculations are to determine the NPSH available for a specific installation. There are generic templates to aid the design engineer setting up the calculations. Two templates are included, one for a vertical turbine pump and one for a horizontal pump. Vertical Turbine NPSH Calculation versus
+
Hatmospheric
ft
submergence above the suction bell.
+
Hsubmergence
ft
-
Hmargin
Compare H submergence versus
-
Hlosses
ft
S submergence, use the greater of the two.
-
Hvapor pressure
ft
NPSHavailable
ft
Altitude (feet) -1000 -500 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000
Hatmospheric (feet) 35.2 34.7 34 33.4 32 8 32.8 32.2 31.6 31 30.5 29.9 29.4 28.8 28.3 27.8 27.3
Temperature Vapor ºF Pressure (ft) 0.2 32 40 0.3 50 0.4 60 0.6 08 70 0.8 1.2 80 90 1.6 100 2.2 2.9 110 3.9 120 5.2 130
5
ft
Electric Motor
Discharge H d Head
Hatmospheric
Low Water Surface Ssubmergence The minimum submergence to
Hsubmergence Ssubmergence
preclude surface vortexing. Refer to pump manufacturer Impeller Eye EL. From Manufacturer Lip of Suction Bell Calculations Page 9 of 11
PF - 6.6.#
Appendix E.5.2 NSPH Worksheet for Horizontal Pumps CALCULATIONS Client: (Client Name Here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Description:
Job No:
Preliminary NPSH Calculations
By:
(Author)
(Enter Job Number) Chkd By:
Header (edit ) Horizontal End Suction or Horizontal Split Case NPSH Calculation Suction Lift Arrangement +
Hatmospheric
ft
-
Hsuction lift
ft
-
Hmargin
-
Hlosses
ft
-
Hvapor pressure
ft
NPSHavailable
ft
5
ft
Horizontal End Suction or Horizontal Split Case NPSH Calculation Suction Head Arrangement Hatmospheric +
ft
+
Hsuction head
ft
-
Hmargin g
-
Hlosses
ft
-
Hvapor pressure
ft
NPSHavailable
ft
Altitude (feet) -1000 -500 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 Calculations Page 10 of 11
Hatmospheric (feet) 35.2 34.7 34 33.4 32.8 32.2 31.6 31 30.5 29.9 29.4 28.8 28.3 27.8 27.3
5
ft
Temperature Vapor ºF Pressure (ft) 32 0.2 40 0.3 50 0.4 60 0.6 70 0.8 80 1.2 90 1.6 100 2.2 110 2.9 120 3.9 130 5.2
PF - 6.6.#
Appendix E.6 Hydraulic Transient Screening Analysis
CALCULATIONS Client: (Client Name here)
Sheet:
of
Project: (Project Name Here)
Date:
mm/dd/yy
Job No:
########
Description: (Description of what is being calculated, specific building, system, discipline, etc…)
By:
(Author)
Chkd By:
Hydraulic Transient Screening Analysis The period is the time it takes the transient to travel the full length of piping and reflect back to the pump. Period = T sec = L/2a , Calculate the period for the suction and discharge piping. L = Pipeline length Suction Piping Period a = speed of pressure wave Discharge Piping Period Pump Moment of Ineria - WR2 Type of System Single transmission pipeline of single diameter Single transmission pipeline of multiple diameters with fluid velocity > 4 fps in smallest diameter Two or more parallel transmission pipelines. One or more transmission pipelines connected to a distribution system
Low
High
Profile of Transmission Line Flat or mild ascending slope (pipeline length > 20x pump TDH) Steep ascending slope (pipeline length < 20x pump TDH) Descending Slope Intermediate High Point Intermediate In-line Pumps Pump S P Suction i Conditions C di i Direct pump suction from wet well, clearwell, or tank Period (2L/a) of suction piping < 1 sec Period (2L/a) of suction piping > 1 sec Questions
Answer (Yes/No)
1. Is the transmission pipeline critical period > 1.5 secs? 2. Is the trasnmission pipeline maximum velocity > 4.0 ft/sec? 3. Will the pump or driver be damaged if the pump is allowed to rotate backward at a reverse speed equipvalent to the maximum forwards speed? 4. Is the factor of safety of the trasmission pipeline < 3.5 for normal operating pressure? 5. Are any transmission piping valves or pump control valves set to automatically open and/or close in < 5 sec? 6. Are any transmission piping valves or pump control valves designed to automatically operate that become inoperative upon loss of pumping system pressure? 7. Will the pump shutdown before the pump discahrge check valve is fully closed? 8. Will the pump startup with the pump discharge valve partially or fully closed?
Calculations Page 11 of 11
PF - 6.6.#
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ATTACHMENT F EXAMPLE DRAWINGS TABLE OF CONTENTS PROCESS AND INSTRUMENTATION DRAWINGS
Dry Pit Submersible Pumps Horizontal Split Case Centrifugal Pumps Progressive Cavity Pumps Rotary Lobe Pumps
Submersible Non-Clog Pumps Vertical Turbine Pumps In Can(w/ Pressure Control) Vertical Turbine Pumps In Wet Well (w/ Level Control) Horizontal Split Case Pumps
Vertical Turbine Pumps (Clear Well) Plant Lift Station Chopper Pump Rotary Lobe Pump Deep Well Pumps Additional Details
MECHANICAL DRAWINGS Large Horizontal Split Case Pumps Large Vertical Non-Clog Pumps / Close Coupled to Motor Large Vertical Non-Clog Pumps / Pumps With Extended Shafts and Flywheels Small Horizontal Split Case Pumps Submersible Non-Clog Pumps Vertical Turbine Can Pumps
This page left intentionally blank
EXAMPLE DRAWINGS PROCESS AND INSTRUMENTATION DRAWINGS
Dry Pit Submersible Pumps Horizontal Split Case Centrifugal Pumps Progressive Cavity Pumps Rotary Lobe Pumps Submersible Non-Clog Pumps Vertical Turbine Pumps In Can(w/ Pressure Control) Vertical Turbine Pumps In Wet Well (w/ Level Control) Horizontal Split Case Pumps
This page left intentionally blank
PUMP NO.1
PUMP NO.2
Pl ot Date: 15-SEP-2011 15:46
LEVEL CONTROL
SPRAY VALVE
RUNTIME
PMP
LAH LAHH 300
300
YA 300
KQI
S/S
SEQ
SEQ
ROT
SETPT
SEL
SEL
TMR
ALL STOP
LK
HS
HS
KIK
LALL LAHH
LIR
300 300A 300A 300B
300
300
AUTO S/S 310A ZL
300
HS
YL
310A 310A 310A
KQI
*
FAIL YA
IIR
PAH
TAH
LAH
310
310
310
310
310
AUTO S/S ZL
HS
*
320A FAIL YL
YA
320A 320A 320A 320
IIR
PAH
TAH
LAH
320
320
320
320
A/M
O/C
HS
HS
TIMER TIMER SET PT
AUTO ZL
302A 302B 302
ZLC
KI
KK
302
302
302
FIR
FQIR
336
336
HMI
HMI
I
I
300B
YA
LIT
300
300
I
I
I
310
320
302
I
300C 300C
* LALL
LSLL LSHH 300
User: tayvaz
RUNTIME
START
SEN WARN FLOOD FAIL
300
300A
ZL
HS
YL
YA
II
310A 310A 310A 310 310
I 3
336
*
PAH
TAH
LAH
LALL
310
310
310
300B
ZL
HS
YL
YA
320A 320A 320A 320
II PAH TAH 320 320 320
FIT HS
LAH 320
ZL
ZLC
302B 302
336
302
L S A
L S A
PLC XX
PLC XX
FIELD
FIELD
RUN
FAIL
RUN RESET
II
YL
YA
TAH
LAH
PAH
310
310
310
310
310
310
HMS
*
310C
0I
II 320
FAIL
YL
YA
TAH
LAH
PAH
320
320
320
320
320
*
0I
I
RESET HMS 320C
I
310
320 PUMP NO.1 STARTER
PUMP NO.2 STARTER
ELECTRICAL ROOM-X
ELECTRICAL ROOM-X
PUMP NO.1 HOA
RUN
FAIL
*
SPRAY VALVE
OFF
PUMP NO.2 HOA
OCA
RUN
FAIL
*
OFF
HS
YL
YA
YL
HS
LALL
HS
YL
YA
YL
310A
310A
310
310B
302
300
320A
320A
320
320B
START
STOP
CLOSED
2
*
FI
Pl otScal e: 2:1
S
START STOP
336A
KQI
PAH
HMS
HMS
I
ZLC
KQI
PAH
HMS
HMS
I
310
310A
310A
310B
310
302
320
320A
320A
320B
310
I I
PUMP NO.1 AND 2 LCP
ZSC 302
UTILITY WATER
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
XX-SOV-302
120VAC
L S A
XX" YY (ZZ)
ENGINEER TO MODIFY BASED ON PROJECT REQUIREMENTS
*
NOTES TO DESIGNER:
LIT 1
300
YS
1.
300 LSHH
LE
LSLL
300
300
ENGINEER TO DECIDE IF PUMPS ARE CONSTANT SPEED OR DRIVEN BY VFD.
300
120VAC DISC HS
M
310
5
PSH
PI
310
310
AND TOP AND BOTTOM BEARINGS AS SHOWN. 3. IF PUMP MOTOR GREATER THAN 300HP, PROVIDE VIBRATION HIGH AND HIGH-HIGH SWITCHES AS SHOWN.
FSL
TSH
310
310
4
XX-V-310C
4
4. IF PUMP IS DRIVEN BY VFD, USE THERMAL FLOW SWITCH TO CONFIRM DISCHARGE FLOW.
*
XX" YY (ZZ)
XX-V-310A XXYY
*
2. IF PUMP MOTOR GREATER THAN 200HP, PROVIDE HIGH TEMPERATURE SWITCHES FOR STATORS
XX-V-310B XXYY
XX-V-310D XXYY
XX-V-310E XXYY
L S A
5. OPTICALLY ISOLATED CURRENT REPEATER MAY BE OPTIONALLY EMPLOYED TO DRIVE LCP DIGITAL DISPLAY.
XX-P-310 PUMP NO.1
ALLOW FOR SUN EXPOSURE WHEN MOUNTING. 120VAC
Col orTabl e: bw.ctb
1" YY (ZZ)
FROM XXX
120VAC
*
DISC HS 320
5
PSH
PI
FIT
320
320
336
1
FSL M
TSH
320
320
XX-V-320C
4
4
XX" YY (ZZ)
XX" YY (ZZ)
TO XXXXX
M M
* XX" YY (ZZ)
XX-V-320A
Model : Defaul t
XXYY
XX-V-320B XXYY
XX-V-320D XXYY
XX-V-320E XXYY
XX-P-320 PUMP NO.2
XX-V-335 XXYY
FE336 XX-V-337 XXYY
METER BYPASS
1" YY (ZZ)
XX-V-338 XXYY
XX" YY (ZZ)
Fi l e: 001 PI D Dry Subm ersi bl e.dgn
NOTES
1
FURNISH AND INSTALL SUNSHIELD.
2
PROGRAMMABLE DIGITAL DISPLAY SHALL BE LOOP POWERED, DUAL RANGE LCD READOUT WITH NEGATIVE AND OVER RANGE INDICATION. DISPLAY UNIT SHALL BE EQUIPPED WITH A NEMA 4X FRONT PANEL.
SCALE
1
REV
DATE
BY
DESCRIPTION
ANNULAR RING SEAL
5
PIPE ARV’S TO SANITARY SEWER
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
*
DESIGNED (PROJECT MANAGER’S NAME)
NO SCALE
SPRAY VALVE INTERLOCKED WITH PUMP RUN STATUS.
4
SUBMITTED BY
WARNING 0
3
LICENSE NO.
DATE
DRAWN
*
PROCESS AND INSTRUMENTATION DIAGRAM
*
DRY PIT SUBMERSIBLE PUMPS
* CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
I-01
FLOW CONTROL LOGIC XXX PUMP NO. 1
XXX PUMP NO. 2
Pl ot Date: 15-SEP-2011 15:46
RUNTIME VFD BY
RUNTIME VFD BY
KQI
REMOTE PASS RDY
S/S
XXX PUMP NO. 3
110
FAIL
ZL
ZL
YL
HS
SC
SI
YL
YA
PAH
PAL
II
TAH
110A
110C
110A
110B
110
110
110B
110
110
110
110
110
ZL
RUNTIME VFD BY
KQI
REMOTE PASS RDY ZL
120
S/S
YL
HS
110A 120C 120A 120B
KQI
REMOTE PASS RDY
FAIL
SC
SI
YL
YA
PAH
PAL
II
TAH
120
120
120B
120
120
120
120
120
ZL
ZL
130
S/S
YL
INF RATIO SETPT
PMP SEQ A/M
PMP SEQ SEL
SC
SI
YL
YA
PAH
PAL
II
TAH
HS
FK
HS
UK
FQIR
FIR
FAL
130
130
130B
130
130
130
130
130
140A
140A
140B
140
122
122
122
HS
110A 130C 130A 130B
A/M
FAIL
I
I
I
I
I
110
120
130
140
140
FI
User: tayvaz
122 ZL
ZL
HS
HS
SC
SI
YL
YA
PAH
PAL
II
TAH
110A
110C
110A
110
110
110
110B
110
110
110
110
110
ZL
ZL
HS
SC
SI
YL
YA
PAH
PAL
II
TAH
120
120
120
120B
120
120
120
120
110
HS
120A 120C 120A
ZL
ZL
HS
SC
SI
YL
YA
PAH
PAL
II
TAH
130
130
130
130B
130
130
130
130
110
HS
130A 130C 130A
L S A
PLC XX
PLC XX
FIELD
FIELD
HOR HS 110A
START
STOP
AMPS
HMS
HMS
II
110A
INV/OFF RESET BYPASS HMS
HS
110
110C
110B
I
2
110 RUN
FAIL
SIC
YL
YA
110
110
110A
110
INV ON
TAH
110
PAH
BYPASS ON
110
HOR PAL
110
ZL
YL
YL
110
110
START
STOP
AMPS
HMS
HMS
II
120A
INV/OFF RESET BYPASS
STDBY ON
110C
HS 120A
HMS
HS
120
120C
120B
HOR PAL
120 RUN
120 FAIL
SIC
YL
YA
FAL
120
120
120A
120
120
BYPASS ON
INV ON
130A
120
PAH
HMS
HS
130
130C
I
ZL
YL
YL
120
120C
120
120
STOP
AMPS
HMS
HMS
II
PAL
TAH
130A
130B
130
130
130
RUN
INV/OFF RESET BYPASS
STDBY ON
VFD OI
START
HS
TAH
FAIL
PAH
SIC
YL
YA
FAL
130
130
130A
130
130
BYPASS ON
INV ON
STDBY ON
I
ZL
YL
YL
130
130C
130
130
VFD OI
VFD OI
NOTES XXX PUMP NO.2 VFD
XXX PUMP NO.3 VFD
Pl otScal e: 2:1
XXX PUMP NO.1 VFD
1
FURNISH AND INSTALL SUNSHIELD.
2
BY PASS STARTER TO VFD OPTIONAL. ENGINEER TO DECIDE.
3
ANNULAR RING SEAL
4
PIPE ARV’S TO SANITARY SEWER
* NOTES TO DESIGNER: 1. IF THE PUMP MOTOR HORSEPOWER IS GREATER THAN 200 HP, PROVIDE HIGH TEMPERATURE SWITCHES FOR STATORS AND TOP AND BOTTOM BEARING AS SHOWN.
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
PSL 110
PI 110B
PSH
PI
110
110A
2. IF PUMP MOTOR GREATER THAN 300 HP, PROVIDE VIBRATION HIGH AND HIGH-HIGH SWITCHES AS SHOWN.
4
LOS TSH
HS M
110
XX-V-140C
110
XX" YY (ZZ)
FROM XX XX-V-110B
XX-V-110C
XX-V-110D
XX-YY
XX-YY
3 XX-P-110 PUMP NO.1
XX" YY (ZZ) L S A
PSL
PI
120
120B
ENGINEER TO MODIFY BASED ON PROJECT REQUIREMENTS
PSH
PI
FIT
120
120A
122
1
LOS HS 120
TSH M
XX-V-140C
110
XX" YY (ZZ)
XX" YY (ZZ)
XX" YY (ZZ)
XX" YY (ZZ) Col orTabl e: bw.ctb
120VAC
TO XX
M M
XX-V-120C XX-YY
XX-V-120B XX-YY
XX-V-120D XX-YY
XX-V-121 XX-YY
FE122
XX-V-123 XX-YY
XX-P-120 XX" YY (ZZ)
PUMP NO.2
XX" YY (ZZ)
XX" YY (ZZ)
XX" YY (ZZ)
Model : Defaul t
XX-V-124 XX-YY
PSL
PI
130
130B
PSH
PI
130
130A
LOS HS 130
TSH M
XX-V-140C
110
XX" YY (ZZ) XX-V-130C XX-YY
Fi l e: 001 PI D Hori zontalSpl i t Case.dgn
XX-V-130B XX-YY
XX-V-130D XX-YY
XX-P-130 PUMP NO.3
XX" YY (ZZ)
XX" YY (ZZ)
SCALE
SUBMITTED BY
WARNING 0
1
(PROJECT MANAGER’S NAME) NO SCALE
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
*
DESIGNED LICENSE NO.
DATE
DRAWN
*
PROCESS AND INSTRUMENTATION DIAGRAM
*
HORIZONTAL SPLIT CASE CENTRIFUGAL PUMPS
* CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
I-02
Pl ot Date: 15-SEP-2011 15:46
PROGRESSIVE CAVITY PUMP NO.1
PROGRESSIVE CAVITY PUMP NO.2
RUNTIME VFD BYPASS REMOTE
RUNTIME VFD BYPASS
KQI 110
FAIL
REMOTE
RDY
S/S
ZL
ZL
YL
HS
SC
SI
YL
YA
PAH
FAL
TAH
PAL
110A
110C
110B
110B
110
110
110A
110
110
110
110
110
ZL
ZL
KQI
RDY
S/S
YL
HS
120
120A 120C 120B 120B
FAIL
SC
SI
YL
YA
PAH
FAL
TAH
PAL
FIR
FQIR
120
120
120A
120
120
120
120
120
110
110
HMI
HMI
I
I
110
120 FI
User: tayvaz
110
LALL
ZL
ZL
HS
SC
SI
YL
YA
PAH
FAL
TAH
PAL
LALL
110A
110C
110A
110
110
110
110B
110
110
110
110
110
100B
ZL
ZL
120C 120A
HS
SC
SI
YL
YA
PAH
FAL
TAH
PAL
120
120
120
120B
120
120
120
120
120
L S A
PLC XX
PLC XX
FIELD
FIELD
HOR
START
STOP
AMPS
HMS
HMS
II
HS 110A
110A
INV/OFF RESET BYPASS HMS
HS
110
110C
110B
I
3
110
110 FAIL
SIC
YL
YA
FAL
110
110
110A
110
110
INV ON
120A
110
RUN
ZL
YL
YL
110
110
HMS
HS
120
120C
I
STOP
AMPS
HMS
HMS
II
PAL
TAH
120A
120B
120
120
120
RUN
INV/OFF RESET BYPASS
STDBY ON
110C
START
HS
TAH
PAH
BYPASS ON
110
HOR PAL
FAIL
PAH
SIC
YL
YA
FAL
120
120
120A
120
120
BYPASS ON
INV ON
STDBY ON
ZL
YL
YL
120C
120
120
3
120 VFD OI
VFD OI
PROGRESSIVE CAVITY PUMP NO.1 VFD
PROGRESSIVE CAVITY PUMP NO.2 VFD
120VAC
XX-V-XXXX
FSL
Pl otScal e: 2:1
S
L S A
110 FI
UTILITY WATER
110 XX-V-110G
XX-V-110I
XX-V-110H
PI
PSL
110A
110
XX" YY (ZZ)
METER BYPASS
120VAC
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
2
2 WIND LOS
XX-V-110A XXYY
M
TSH
HS
110
110
PI
PSH
FIT
110B
110
110
XX-V-110F XXYY
1 2
XX" WAS (26)
2
XX" YY (ZZ) TO XXXXX
M M
XX" WAS (26) XX-P-110 PROGRESSIVE CAVITY PUMP NO.1
XX-V-110B
XX-V-110C
XXYY
XXYY
XX-V-110D XXYY
FE-110
XX-V-110E XXYY
XX-V-110D XXYY
120VAC
XX-V-XXXX
ENGINEER TO MODIFY BASED ON PROJECT REQUIREMENTS
FSL S
120
XX-V-XXXX
FI 120
Col orTabl e: bw.ctb
XX-V-120G
XX-V-120H
XX-V-120I
PI
PSL
120A
120
2
FROM XXXXX
2 WIND LOS
XX-V-120A XXYY
M
TSH
HS
120
120
PI
PSH
120B
120
Model : Defaul t
2
2
6" WAS (26)
XX-P-120
XX-V-120B
XX-V-120C
PROGRESSIVE CAVITY PUMP NO.2
XXYY
XXYY
XX-V-120D XXYY
Fi l e: 001 PI D Progressi ve Cavi ty.dgn
NOTES
SCALE
1
REV
DATE
BY
DESCRIPTION
ANNULAR RING SEAL
3
BYPASS STARTER TO VFD OPTIONAL. ENGINEER TO DECIDE.
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
*
DESIGNED (PROJECT MANAGER’S NAME)
NO SCALE
FURNISH AND INSTALL SUNSHIELD.
2
SUBMITTED BY
WARNING 0
1
LICENSE NO.
DATE
DRAWN
*
PROCESS AND INSTRUMENTATION DIAGRAM
*
PROGRESSIVE CAVITY PUMPS
* CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
I-03
XX PUMP NO. 1
XX PUMP NO. 2
Pl ot Date: 15-SEP-2011 15:46
RUNTIME VFD BYPASS RDY S/S
ZL
YL
ZL
HS
220A 210B 210C 210
RUNTIME VFD BYPASS S/S RDY
KQI
REMOTE
FAIL
SC
SI
YL
YA
PAH
PAL
II
TAH
210
210
210A
210
210
210
210
210
I
ZL
YL
220
HS
ZL
SC
220A 220B 220C 220
SI
220
YA
PAH
PAL
II
TAH
220
220
220
220
I
FROM PUMP CONTROL LOGIC
210
FAIL
YL
220 220A 220
ZL
YL
ZL
230
HS
SC
220A 230B 230C 230
SI
230
FAIL YA
230 230A 230
PAH
PAL
II
TAH
230
230
230
220
I
FROM PUMP CONTROL LOGIC
220
REMOTE
YL
FLOW/
RUNTIME VFD BYPASS S/S RDY
KQI
REMOTE
XX PUMP CONTROL LOGIC
XX PUMP NO. 4
RUNTIME VFD BYPASS S/S RDY
KQI
REMOTE
210
XX PUMP NO. 3
ZL
YL
ZL
HS
SC
220A 240B 240C 240
SI
240
24-HOUR HOUR
PMP
SET
FQI
SEQ
SEQ SYSTEM
240
SEL
PT
246
SEL
A/M
FAIL
YL
YA
240 240A 240
VARIES
XX
PMP
TOTAL
DEPENDING ON SOURCE
A/M
PAH
PAL
II
TAH
PIR
PAH
HS
FQK
FK
FIR
FAL
UK
HS
HS
HS
240
240
240
240
247
247
246
246
246
246
246
246
246
246
246
I
FROM PUMP CONTROL LOGIC
230
24-
KQI
I
FROM PUMP CONTROL LOGIC
240
I
I 246
TO XX
277
PUMPS
246B SEL TANK LAHH
LAHH
ZL
ZL
User: tayvaz
200A 210A 210C
HS
SC
SI
YL
YA
PAH
PAL
II
TAH
LAHH
210
210
210
210A
210
210
210
210
210
200B 220A 220C 220
ZL
ZL
HS
SC
SI
220
YL
YA
220 220A 220
PAH
PAL
II
TAH
LAHH
220
220
220
220
200C 230A 230C 230
ZL
ZL
HS
SC 230
SI
YL
YA
230 230A 230
PAH
PAL
II
TAH
LAHH
230
230
230
230
200D 240A 240C 240
ZL
ZL
HS
SC
SI
240
YL
YA
240 240A 240
PAH
PAL
II
TAH
PI
FI
240
240
240
240
277
276
L S A
L S A
PLANT PLC
PLANT PLC FIELD
FIELD
HOR
HOR HS 210A
INV/OFF RESET BYPASS HMS
HS
210
210C
START
STOP
AMPS
HMS
HMS
II
PAL
TAH
210A
210B
210
210
210
RUN
FAIL
PAH
SIC
YL
YA
210
210
210A
210
BYPASS ON I 210
4
INV ON
HMS
HS
220
220C
ZL
YL
YL
210
210
HMS
II
PAL
TAH
220B
220
220
220
RUN SIC
YL
YA
220
220A
220
220
INV ON YL
YL
220C
220
220
HMS
HS
230
230C
STOP
AMPS
HMS
HMS
II
PAL
TAH
230B
230
230
230
SIC
YL
YA
230
230A
230
4
INV ON
230
YL
YL
230C
230
230
HS
240
240C
AMPS
HMS
II
PAL
TAH
240B
240
240
240
RUN
FAIL
PAH
SIC
YL
YA
240
240
240A
240
BYPASS ON
INV ON
STDBY ON
ZL
YL
YL
240C
240
240
4
240
STOP
HMS 240A
VFD OI
VFD OI
XX PUMP NO.2 VFD
XX PUMP NO.1 VFD
HMS
I
VFD OI
VFD OI
INV/OFF RESET BYPASS
STDBY ON
ZL
START
HS 240A
FAIL
PAH 230 BYPASS ON
I
HOR
230A
RUN
INV/OFF RESET BYPASS
STDBY ON
ZL
4
START
HS 230A
FAIL
PAH 220 BYPASS ON
I
AMPS
HMS 220A
INV/OFF RESET BYPASS
STDBY ON
210C
STOP
START
HS 220A
HOR
XX PUMP NO.4 VFD
XX PUMP NO.3 VFD
ENGINEER TO MODIFY BASED ON PROJECT REQUIREMENTS
XX" YY (ZZ) XX-V-210C XXYY
PI
Pl otScal e: 2:1
3 TSH
HS
210
210
XX-V-210D XXYY
210B
PSH 210
M
PSL
XX-P-210
210
XX PUMP NO.1
PI
3
L S A
2
L S
BYPASS
120VAC A
210A
1
XX" YY (ZZ)
XX" YY (ZZ)
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
FROM XX
PIT
1
FIT
247
XX-V-210A XXYY 1" YY (ZZ)
XX-V-210B XXYY
XX-V-220C XXYY
PI 3
246
XX-V-220D XXYY
220B XX" YY (ZZ)
TSH
HS
220
220
M M
PSH XX-V-248 XXYY
220
FE-246
M
XX" YY (ZZ)
PSL 220
XX-P-220 XX PUMP NO.2
PI 3
2 XX-V-250D
220A
XX" YY (ZZ)
BYPASS LINE
XXYY XX-V-220A XXYY
XX-V-220B XXYY
XX" YY (ZZ)
1" YY (ZZ) 3
Col orTabl e: bw.ctb
TO XX
XX-V-249 XXYY
TSH
HS
230
230
XX-V-230C
XX-V-230D
XXYY
XXYY
PI
NOTES
230B
1
FURNISH AND INSTALL SUNSHIELD
PSH 230
2
THE FURNISHED PUMP SHALL BE EQUIPPED WITH AN INTEGRAL PRESSURE RELIEF OR BYPASS SYSTEM TO
M
PROTECT THE PUMP FROM OVER PRESSURIZATION
PSL
XX-V-230
3
WILL BE AS DEFINED IN THE DIVISION 11 SPECIFICATIONS.
2
230A
XX" YY (ZZ)
XX-V-230A XXYY
Model : Defaul t
PI
XX-V-230B XXYY
DURING A DEAD-HEAD CONDITION. THIS SYSTEM
XX" YY (ZZ)
230 XX PUMP NO.3
3
TSH
HS
240
240
PI
XX-V-240C
XX-V-240D
XXYY
XXYY
3
ANNULAR RING SEAL.
4
BY PASS STARTER TO VFD OPTIONAL. ENGINEER TO DECIDE.
240B
PSH 240
1" YY (ZZ)
M
PSL 240
XX-V-240 XX PUMP NO.4
Fi l e: 001 PI D Rotary Lobe.dgn
XX-V-240A XXYY 1" YY (ZZ)
SCALE
BY
DESCRIPTION
2
XX-V-240B XXYY
1
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
*
DESIGNED (PROJECT MANAGER’S NAME)
NO SCALE
DATE
PI
SUBMITTED BY
WARNING 0
REV
3
240A
XX" YY (ZZ)
LICENSE NO.
DATE
DRAWN
*
PROCESS AND INSTRUMENTATION DIAGRAM
*
ROTARY LOBE-XX PUMPS
* CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
I-04
PUMP NO.1
PUMP NO.2
PUMP NO.3
PUMP NO.4
RUNTIME
RUNTIME
RUNTIME
RUNTIME
LIFT STATION LEVEL CONTROL LOGIC
PMP
Pl ot Date: 15-SEP-2011 15:46
KQI AUTO 110A
KQI AUTO 120A
FAIL
KQI AUTO 130A
FAIL
KQI AUTO 140A
FAIL
FAIL
LEVEL
SEN
SEN
A/M
DIFF
FAIL
FAIL
FIR
YL
YL
YA
YL
YL
YA
YL
YL
YA
YL
YL
YA
HS
LDAH
130
110
110A
110
120
120A
120
130
130A
130
140
140A
140
130A
130
I
I
I
I
110
120
130
140
FIT
YA
LALL 135A
HS
YL
110
110
YL 110A
YA 110
LALL
HS
135B
120
YL YL 120 120A
YA 120
LALL
HS
135C
130
YL YL 130 130A
YA 130
LALL
HS
135D
140
YL YL 140 140A
YA
LAHH LALL
LK
HS
US
130
130B
130
135
135
I
I
140
135
YA 140
LAHH LALL 135
L S A
PLC XX
LIR
PMP FLOOD STOP
LIT LIT YA YA 130A 130A 130B 130B
130
User: tayvaz
LIR
130A 130A 130A 130B
S/S LEVEL SEQ SEL SEL
SET
L S A
135
L S A
PLC XX
FIELD
FIELD
1
BEACON
PUMP NO.1
HOA
RUN
PUMP NO.2
HOA
RUN
PUMP NO.3
HOA
RUN
PUMP NO.4
HOA
RUN
ALARM HORN
PAH
TAH
HS
YL
PAH
TAH
HS
YL
PAH
TAH
HS
YL
PAH
TAH
HS
YL
YA
LAHH
LALL
140
140
110
110A
140
140
120
120A
140
140
130
130A
140
140
140
140A
130
135
135
HORN SILENCE
FAIL
FAIL
FAIL
FAIL
MAH
YA
KQI
MAH
YA
KQI
MAH
YA
KQI
MAH
YA
KQI
140
110
110
140
120
120
140
130
130
140
140
140
2 HMS
I
I
I
I
110
120
130
140
130 LIFT STATION NO.XX LCP (REFERENCE SPECIFICATION SECTION 11148)
TS
Pl otScal e: 2:1
L S A
130 SHUT DOWN FOR
120VAC 2 FIT 130
PI
MOISTURE AND
150
HIGH TEMP.
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
XX-V-151 XX" YY (ZZ) TO XX
TO XX
M M
FE-130
XX-V-150
XX-YY
XX-V-120B XX-YY
XX-V-130B XX-YY
XX-V-140B XX-YY
XX-V-110A
XX-V-120A
XX-V-130A XX-YY
XX-V-140A
XX-V-110B
XX-YY
Col orTabl e: bw.ctb
XX-V-153
3
XX-YY
XX-YY
PSH
PSH
PSH
PSH
130
130
130
130
L S
L S
120VAC A
120VAC A
LSHH 135
2
LIT
YS
130
130
2
LIT
YS
130
130
LSLL
LE
LE
135
130
130
ENGINEER TO MODIFY BASED ON PROJECT REQUIREMENT
XX" YY (ZZ)
Model : Defaul t
FROM XY
FROM XX
XX" YY (ZZ)
XX" YY (ZZ)
MSH
MSH
MSH
150
150
150
TSH 150
TSH M
150
MSH 150
TSH M
150
TSH M
150
M
NOTES:
Fi l e: 001 PI D Subm ersi bl e Noncl og.dgn
1
XX-P-110
XX-P-120
PUMP NO.1
PUMP NO.2
XX-P-130 PUMP NO.3
2
XX-P-140
BEACON ACTIVATED UPON LAHH DETECTION.
STANCHION MOUNT OUTSIDE CLASSIFIED AREA. FURNISH AND INSTALL SUNSHIELD.
PUMP NO.4 3
ANNULAR RING SEAL
PUMP STATION-XXX
SCALE
SUBMITTED BY
WARNING 0
1
(PROJECT MANAGER’S NAME) NO SCALE
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
*
DESIGNED LICENSE NO.
DATE
DRAWN
*
PROCESS AND INSTRUMENTATION DIAGRAM
*
SUBMERSIBLE NON-CLOG PUMP STATION XXX
* CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
I-05
Pl ot Date: 15-SEP-2011 15:46
VFD BYPASS REMOTE RDY
PUMP NO. 1
PUMP NO. 2
PUMP NO. 3
PUMP NO. 4
RUNTIME
RUNTIME
RUNTIME
RUNTIME
VFD BYPASS REMOTE RDY
KQI S/S
110
FAIL
LALL
ZL
ZL
YL
HS
SC
SI
YL
YA
PAH
FAL
TAH
VAH
110A
110A
110C
110A
110B
110
110
110B
110
110
110
110
110
ZL
ZL
VFD BYPASS REMOTE RDY
KQI S/S
YL
HS
120A 120C 120A 120B
120
FAIL
SC
SI
YL
YA
PAH
FAL
TAH
VAH
120
120
120B
120
120
120
120
120
ZL
ZL
VFD BYPASS REMOTE RDY
KQI S/S
YL
HS
130A 130C 130A 130B
130
FAIL
SC
SI
YL
YA
PAH
FAL
TAH
VAH
130
130
130B
130
130
130
130
130
ZL
ZL
PRESSURE CONTROL LOGIC
TOT FLOW RECLAIM SYS. A/M A/M SEQ
KQI 140
S/S
YL
SC
SI
YL
YA
PAH
FAL
TAH
VAH
HS
140
140
140B
140
140
140
140
140
150A
HS
140A 140C 140A 140B
FAIL
HS
SEQ SEL
TXD SEL
HS
HS
A/M TXD PRESS SEL SETPT HS
150B 150C 150D 150E
PDAH
FQIR
FAH
150
150
150
PK
PAL
PAH
150
150
150
PIR
150A 150B
FIR 150A
VAULT FLOOD
FK
LAH
150
150
HMI
HMI FLOW LIMITER
I
I
I
I
I
110
120
130
140
I
150B
LSLL User: tayvaz
PIR
MAX DISCH RATE PER PMP
150
VALUE
150A
LALL
ZL
100A 110C
ZL
HS
SC
SI
YL
YA
PAH
FAL
TAH
VAH
110A
110
110
110
110B
110
110
110
110
110
ZL
LALL
ZL
100B 120C 120A
HS
SC
SI
YL
YA
PAH
FAL
120
120
120
120B
120
120
120
TAH 120
VAH 120
LALL
ZL
HS
SC
SI
YL
YA
PAH
130
130
130
130B
130
130
ZL
100C 130C 130A
FAL 130
TAH 130
VAH 130
LALL
ZL
HS
SC
SI
YL
YA
PAH
FAL
TAH
VAH
140
140
140
140B
140
140
140
140
140
ZL
100D 140C 140A
PI
PI
LAH
150A 150B
150
TO PUMP L S A
L S A
CONTROL LOGIC
L S A
PLC XX
PLC XX
FIELD
FIELD
HOR HS 110A
START
STOP
AMPS
HMS
HMS
II
110A
INV/OFF RESET BYPASS HMS
HS
110
110C
I
110
110
RUN
FAIL
SIC
YL
YA
VAH
110
110
110A
110
110
BYPASS ON
INV ON
HS 120A
110
PAH
START
STOP
AMPS
HMS
HMS
II
120A
INV/OFF RESET BYPASS HMS
HS
120
120C
STDBY ON
ZL
YL
YL
LALL
I
110C
110
110
100A
120
6
110
110B
HOR FAL
TAH
120B
HOR TAH 120
RUN
FAIL
PAH
SIC
YL
YA
VAH
120
120
120A
120
120
BYPASS ON
INV ON
II
INV/OFF RESET BYPASS
STDBY ON
HMS
HS
130
130C
ZL
YL
YL
LALL
I
120
120
100B
130
130B
HOR TAH 130
RUN
FAIL
PAH
SIC
YL
YA
VAH
130
130
130A
130
130
BYPASS ON
INV ON
PUMP NO.1 VFD
140A
130
130
INV/OFF RESET BYPASS
STDBY ON
HMS
HS
140
140C
ZL
YL
YL
LALL
I
130C
130
130
100C
140
6
PUMP NO.2 VFD
6
STOP
AMPS
HMS
HMS
II
TAH
FAL
140A
140B
140
140
140
RUN
FAIL
PAH
SIC
YL
YA
VAH
140
140
140A
140
140
BYPASS ON
INV ON
STDBY ON
ZL
YL
YL
LALL
140C
140
140
100D
VFD OI
VFD OI
PUMP NO.3 VFD
PUMP NO.4 VFD
ENGINEER TO MODIFY BASED ON PROJECT REQUIREMENT FROM BACKUP SEAL WATER SYSTEM
" UW (14)
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
UTILITY SEAL WATER
L S A
L S A
2
S
S
S
L S A
2 120VAC
2
PIT
PIT
FIT
150A
150B
150
S
LSH 150 XX-V-110A
XX-V-110B
XX-V-130A
XX-V-120B
XX-V-120A
1
XX-V-130B
1
XX-V-140B
XX-V-140A
1
1
FI
FI
FI
FI
110
120
130
140
120VAC
120VAC
120VAC
120VAC M M
XX-V-151 FSL
FSL
110
LOS
5 Col orTabl e: bw.ctb
HS 110
WIND
FSL
120
130
5
LOS
M
VSH
140
5
LOS
110 VIB
110
WIND
5
LOS
WIND FLOWMETER VAULT
HS 120
L S A
WIND
TO XXXXXX
FE-150 XX-V-152
FSL
TSH
M
PSH
PI
110
110
VSH 120
TSH 120 VIB
2
PI
120
120
TSH
HS
TSH
130
130
140
140
VSH 130
VIB
M
PSH
PI
130
130
VSH
4
VIB
140
4
XX-V-120C
XX-V-110C
LSLL
HS M
PSH
4
XX-V-153 PSH
PI
140
140
FLOWMETER BYPASS 4
XX-V-130C
XX-V-140C NOTES:
150A XX-V-110D XX-V-110E
XX-V-120D XX-V-120E
XX-V-130D XX-V-130E
XX" YY (ZZ)
XX-V-140D
XX" YY (ZZ)
XX" YY (ZZ)
Model : Defaul t
XX" YY (ZZ)
Fi l e: 001 PI D Verti calTurb CAN.dgn
START
HS
FAL
VFD OI
VFD OI
Pl otScal e: 2:1
AMPS
HMS
130A
120C
6
STOP
HMS
130A
120
120
START
HS
FAL
XX-P-110
XX-P-120
XX-P-130
XX-P-140
XX PUMP NO.1
XX PUMP NO.2
XX PUMP NO.3
XX PUMP NO.4
XX-V-110F
XX-V-120F
XX-V-130F
XXYY
XXYY
XXYY
XX-V-140E
1
REFER STANDARD DETAIL M-826 FOR SEAL WATER SYSTEM DETAILS
2
FURNISH AND INSTALL SUNSHIELD.
3
REJECT MODE PUMP SHUTDOWN OUTPUT
4
PIPE ARV’S TO SANITARY SEWER
5
SEAL WATER PANEL. SEE DETAIL M-XX.
6
BYPASS STARTER TO VFD OPTIONAL. ENGINEER TO DECIDE.
XX-V-140F XXYY
FROM XXXX
SCALE
SUBMITTED BY
WARNING 0
1
(PROJECT MANAGER’S NAME) NO SCALE
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
*
DESIGNED LICENSE NO.
DATE
DRAWN
CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
*
PROCESS AND INSTRUMENTATION DIAGRAM
*
VERTICAL TURBINE PUMPS IN CAN
*
WITH PRESSURE CONTROL
I-06
TRANSFER STATION WET WELL
XX PUMP NO. 1
LEVEL CONTROL LOGIC
XX PUMP NO. 2
Pl ot Date: 15-SEP-2011 15:46
RUNTIME
HS
HS
100A 100B
VFD BY REMOTE PASS
LEAD/ LEVEL LAG SETPT SEL
TRANS SEL TRANS A/M 1 /2 LIR
LK
UK
100
100
100
LALL LAHH 100
100
KQI 110
FAIL
RDY
S/S
ZL
ZL
YL
HS
SC
SI
YL
YA
PAH
FAL
II
TAH
VAH
110A
110C
110B
110
110
110
110A
110
110
110
110
110
110
ZL
FAIL
RDY
S/S
YL
HS
SC
SI
YL
YA
PAH
FAL
II
TAH
VAH
120
120
120
120A
120
120
120
120
120
120
ZL
120A 120C 120B
I
I
I
I
100A
100B
110
120
RUNTIME
VFD BY REMOTE PASS RDY
KQI 120
XX PUMP NO. 4
XX PUMP NO. 3
RUNTIME VFD BY REMOTE PASS
ZL
ZL
KQI S/S
YL
130A 130C 130B
HS 130
SC
130
FAIL
YL
YA
SI
130
130
130A
PAH
130
RUNTIME
VFD BY REMOTE PASS RDY FAL
130
130
II 130
TAH 130
ZL
VAH
ZL
KQI
YL
140A 140C 140B
130
140
S/S
FAIL
HS
SC
SI
YL
YA
PAH
FAL
II
TAH
VAH
PIR
FIR
FQIR
140
140
140
140A
140
140
140
140
140
140
120
120
120
I
I
130
140
I 140
SEL TANK LAHH LI
LI
100A 100B
LALL LAHH 100
100 LALL
ZL
User: tayvaz
100A 110C L S A
ZL
HS
SC
SI
YL
YA
PAH
FAL
II
TAH
VAH
110A
110
110
110
110A
110
110
110
110
110
110
LALL
ZL
ZL
100B 120C 120A
HS
SC
SI
YL
YA
PAH
FAL
II
TAH
VAH
120
120
120
120A
120
120
120
120
120
120
ZL
HS
SC
SI
YL
YA
PAH
FAL
II
TAH
VAH
LALL
130
130
130
130A
130
130
130
130
130
130
100D 140C 140A
ZL
100C 130C 130A
L S A
ZL
ZL
HS
SC
SI
YL
YA
PAH
FAL
II
TAH
VAH
140
140
140
140A
140
140
140
140
140
140
PLANT PLC
PI
FI
120
120
L S A
L S A
FIELD
PLC XX FIELD
HOR HS 110A
START
STOP
AMPS
HMS
HMS
II
110A
INV/OFF RESET BYPASS HMS
HS
110
110C
110B
HOR TAH
110
110
RUN
FAIL
SIC
YL
YA
VAH
110
110A
110
110
INV ON
120A
110
110
START
STOP
AMPS
HMS
HMS
II
HS
FAL
PAH
BYPASS ON
120A
HS
120
120C
STDBY ON
120
120
RUN
INV/OFF RESET BYPASS HMS
120B
HOR TAH
SIC
YL
YA
VAH
120
120
120A
120
120
BYPASS ON
INV ON
130A
120
PAH
START
STOP
AMPS
HMS
HMS
II
HS
FAL
FAIL
130A
HMS
HS
130
130C
130B
HOR TAH
130 RUN
INV/OFF RESET BYPASS
STDBY ON
130
140A
130
FAIL
SIC
YL
YA
VAH
130
130
130A
130
130
INV ON
START
STOP
HMS
HMS
II
TAH
FAL
140A
140B
140
140
140
HS
FAL
PAH
BYPASS ON
RUN
INV/OFF RESET BYPASS
STDBY ON
HMS
HS
140
140C
AMPS
FAIL
PAH
SIC
YL
YA
VAH
140
140
140A
140
140
BYPASS ON
INV ON
STDBY ON
I
ZL
YL
YL
LALL
I
ZL
YL
YL
LALL
I
ZL
YL
YL
LALL
I
ZL
YL
YL
LALL
110
110C
110
110
100A
120
120C
120
120
100B
130
130C
130
130
100C
140
140C
140
140
100D
VFD OI
VFD OI
VFD OI
XX PUMP NO.3 VFD
XX PUMP NO.4 VFD
VFD OI XX PUMP NO.2 VFD
XX PUMP NO.1 VFD
Pl otScal e: 2:1
UTILITY SEAL WATER " UW (14)
NOTES:
1
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
ENGINEER TO MODIFY BASED ON PROJECT REQUIREMENT
2
S
FROM BACKUP SEAL WATER SYSTEM
S
XX-V-110B
XX-V-110A
1
XX-V-120A
S
XX-V-120B
FI
1
FI 120
FURNISH AND INSTALL SUNSHIELD
3
SEAL WATER PANEL. SEE DETAIL M-XX.
4
BYPASS STARTER TO VFD OPTIONAL. ENGINEER TO DECIDE.
XX-V-140B
XX-V-140A
1
FI 130
L S A
FI 140
120VAC
120VAC
120VAC
REFER TO STANDARD DETAIL M-826 FOR SEAL WATER SYSTEM DETAILS
S
XX-V-130B
XX-V-130A
1
110
FSL
FSL
FSL
110
120
130
120VAC
120VAC
FSL 140
L S A
FIT 120
PIT 120
LOS HS
Col orTabl e: bw.ctb
L S 120VAC A
LSHH 100
YS
LIT
100A 100A
L S A
2 LIT
110
3
WIND
M M
LOS
TSH 110 3
VSH 120VAC
M
VIB
HS
TSH
120
120
3
LOS
WIND
HS
TSH
130
130
WIND XX-V-150A
3
HS
TSH
140
140
FE120
XX-V-150B TO XXXXXX BYPASS LINE
110
YS
LOS
WIND
M
PSH
PI
110
110
VSH
VIB
120
M
PSH
PI
120
120
VSH 130
VIB
M
PSH
PI
130
130
VSH 140
VIB PSH
PI
140
140
XX-V-150C
100B 100B XX-V-120C
XX-V-110C LSLL
LE
LE
100
100A
100B XX-V-110D
XX-V-110E
XX-V-140C
XX-V-130C
XX-V-120D XX-V-120E
XX" YY (ZZ)
XX" YY (ZZ)
XX-V-130D XX-V-130E
XX-V-140D XX-V-140E
XX" YY (ZZ)
XX" YY (ZZ)
XX" YY (ZZ) FROM XXXX
Fi l e: 001 PI D Verti calTurb W W .dgn
Model : Defaul t
LALL
XX-P-110
XX-P-120
XX-P-130
XX-P-140
XX PUMP NO.1
XX PUMP NO.2
XX PUMP NO.3
XX PUMP NO.4
ENGINEER TO MODIFY BASED ON PROJECT REQUIREMENT
WET WELL
SCALE
SUBMITTED BY
WARNING 0
1
(PROJECT MANAGER’S NAME) NO SCALE
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
*
DESIGNED LICENSE NO.
DATE
DRAWN
CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
*
PROCESS AND INSTRUMENTATION DIAGRAM
*
VERTICAL TURBINE PUMPS IN WET WELL
*
WITH LEVEL CONTROL
I-07
Pl ot Date: 15-SEP-2011 15:46
MASTER PLC
EMERG.
NORMAL.
SHUTDOWN
SHUTDOWN
SYS. LOW DIFF. PRESS.
VALVES
DIVERSION
PROPERLY
STRUCTURE
FLOW
POSITION
LEVEL
CONTROL
RUN STATUS I-13 FROM VFD P-200 PLC
HS
HS
PDAL
ZL
LAL
FIC
271
272
073-2
074-2
060-2
022-2
TO VFD P-300 PLC I-9[A]
AI-7[A]
SERIAL COMMUNICATIONS
REM/MAN RST
ZL
ALARM
ZL
YL
ZL
CONE
PUMP
FLOW
VALVE
VIB.
PRESS.
LOW
FAIL
HIGH
HI-HI PRESS
VIB.
VLV
DIV.
DISCH.
DIFF
STRUCT.
ISO VLV
ISO VLV ISO VLV
SPEED
FLOW
TRANS.
VLV
VLV
FCV
INTMED
FCV
FCV
TEMP
TEMP
HYD.
VFD
DPRES
SPEED
PRESS
LEVEL
INTERM
CLOSED
OPEN
INDIC.
LOW
HI TEMP
CLSD
OPEN
POS.
POS.
CLSD
OPEN
HI-HI
HIGH
PRESS
FAIL
CLSD
STPNT
STPNT
INDIC.
ZLO
SI
FAL
TAH
ZLC
ZLO
ZI
ZLM
ZLC
ZLO
TAHH
TAH
PI
YA
ZLC
SK
PDIK
SI
260B
201B
201B
202B
202B
202B
202B
264B
264B
270B
213B
266B
251B
202B
251-2B
DIFF
DISCH.
PAL
YA
KQI
PAL
FAL
YA
VAH
VAHH
PDI
PDI
LAL
ZL
ZLC
252B
233B
211B
253B
203B
202B
264B
264B
211B
202B
060B-2
204B
204B
YL
215-1A 215-2A 215-3A 216A 217A 212A 218A 261A
VAH
VAHH
ZLO
ZLC
PAL
TAHH
TAH
264A
264A
201A
201A
252A
264A
264A
LAL
YL
KQI
060A-2 232A
FAL
216A 251-1A 203A
211A
WATER ISOLATION
204B 251-1B 221B
SI
YL
DISCH.
ZLC
ZLO
TAH
204A
204A
260A
INLET
PDI 211A
INLET
FCV
VFD
YL
YA
YA
ZLO
ZLC
213A
213A
202A
202A
202A
TSH
ZI
HS
PDI
HS
202A 202-1A202-2A 202A
260 VIBRATION MONITOR PANEL
UPS
VFD MOTOR CONTROL
MOTOR PROTECTION RELAY
FCV
CNTCTR SPEED
PI
ZL
PAL
202A
220A
253A
SI
PI
270A 251-2A
READY
ZL
RESET
CONTROL
SPEED
ZL
TIME
SYSTEM
ZL
SEAL LOW
ELAPSED DISCH.
M AJOR VI B. ALARM (COM M ON)
FAL 221A
FAIL
MI NOR VI B. ALARM (COM M ON)
YA 233A
STOP
START
STOP
EM ERG.
HAND
REM OTE
OFF
NORM AL
PLC
MTR UPS
PRESS.
POW ER ON
PUMP
LOW SUCTION
CONTROL
HMI
SHTDW N
220
EM ERG.
251
RUN
218
OFF
217
M OTOR
216
COM M S
215
SERI AL
HS
I SOLATI ON TRANSF. HI GH TEM P
HS
COM M S
HS
SERI AL
STOP
HS
PREALARM
START
HS
EM - SHTDW N
ESTOP
COM M S
HOR
HS
SERI AL
User: tayvaz
PLC COMMUNICATIONS NETWORK
YL
YL
YL
YL
YL
212
213
216
232
261
C
ZSO
HS
HS
201B
201A
201
M
252
2
FLY WHEEL 2
VE
VE
2
DI FF. PRESSURE
VE
ZSC
212-2
202
VE
PI 253
212-1
2
OPEN
CLOSED ZSC 204
202 O
2
VE
2
FLOW
ZSO
TE 233
215
LOW
DI FF. PRESSURE
CLOSED
OPEN
POSI TI ON
CLOSED
OPEN
FAI L
PRESSURE LOW
PRESSURE
M OTOR CONTROL
TEM P. SENSOR 1
2
213-2
213-1 2
HYDRAULIC CONTROL SYS. LCP POSI TI ON
236
270
CLOSED
TE
235
PLC PIT
OPEN
TE
2
238
2
SENSOR 2
SENSOR 2 TE
M
237
PUM P OUTBOARD BEARI NG
TE 240
PUM P TACHOM ETER SPEED
TE 239
TE
TEM P. SENSOR 2
2
M OTOR W I NDI NG
TE 232 2
TEM P. SENSOR 4
2
M OTOR W I NDI NG
VE 214-2
214-1
PUM P I NBOARD RADI AL BEARI NG
SENSOR 2
2 2
VE
TEM P. SENSOR 6
214-3
BEARI NG
SIT 251-2
VE
M OTOR W I NDI NG
M TR TEM P
M TR OUTB
M TR AXI AL, BEAR. 3
2 VE 214-4
M OTOR OUTBOARD RADI AL
BEARI NG
SENSOR 1
M OTOR OUTBOARD RADI AL
2
2
M OTOR I NBOARD RADI AL BEARI NG
2
TEM P. SENSOR 1
M OTOR OUTBOARD BEARI NG
TEM P. SENSOR 5 M OTOR W I NDI NG
TEM P. SENSOR 3 M OTOR W I NDI NG
SENSOR 1
TEM P. SENSOR 1 M OTOR W I NDI NG
M OTOR I NBOARD RADI AL BEARI NG
M OTOR I NBOARD BEARI NG
TEM P. SENSOR 1
SENSOR 1
KEYPHASOR SENSOR
PUM P I NBOARD RADI AL BEARI NG
PUM P I NBOARD BEARI NG
SENSOR 3
SENSOR 1
TEM P. SENSOR 1
PSL
SENSOR 2
SENSOR 4
PI 252
PUM P OUTBOARD RADI AL BEARI NG
201
L/R
PUM P OUTBOARD RADI AL BEARI NG
Model : Model Col orTabl e: bw.ctb
O/C
PUM P OUTBOARD RADI AL BEARI NG
ZSC
PUM P OUTBOARD AXI AL BEARI NG
PRESSURE LOW OPEN
CLOSED
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
Pl otScal e: 2:1
VARIABLE FREQUENCY DRIVE 2
PSL
E
253
H
TE
O/C C
ZIT 202
HS FSL 203
L/R HS
204B
C ZSO 204 O
204A
234
O
2
36" UW (8) I-6[D]
54" UW (8) I-6[C] PI 221
P-200
HV-201
2 2 2
NOTES:
VE
SIT
211-3
251-2
211-1
ALL NECESSARY I/O POINTS TO THE PLCS IN ADDITION TO THE HARDWIRED I/O. 2
221
CV-203
FCV-202
HV-204
PDI SET 50PSI
221
PDIT
SET 60PSI
202
2 VE
1. ALL COMMUNICATION LINKS SHALL PROVIDE
FSL
TE 2
231 VE 211-2
PREPURCHASED EXISTING EQUIPMENT
VE
CYCLONE SEPARATOR
2
211-4 PDIT
RELOCATED AND / OR INSTALLED BY CONTRACTOR.
PW
DUPLEX STRAINER
D
Fi l e: 001 PI D z Large HSC
PI D.dgn
211
SCALE
SUBMITTED BY
WARNING 0
1
DESIGNED
DESIGN
DRAWN
DRAWN
(PROJECT MANAGER’S NAME) SCALE
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
CHECKED
CHECKED
SHEET
LICENSE NO.
DATE
OLIVEHAVEN PUMP STATION
EXAMPLE HORIZONTAL SPLIT CASE PUMP STATION
AND OLV8FCF PROJECT
MECHANICAL
I-08
P & ID (COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
Job No.
EXAMPLE DRAWINGS MECHANICAL – LARGE HORIZONTAL SPLIT CASE Mechanical Plan Mechanical Section
This page left intentionally blank
Pl ot Date: 15-SEP-2011 16:01
-
A
152’-0"
ISOLATION VALVE VAULT IVV2
1
2
3
4
5
6
7
8
9
CONE VALVE ACCUMULATOR RACK (TYP)
78" UW (8)
User: tayvaz
PIPE ENCASEMENT
78" UW (8)
CONE VALVE HYDRAULIC POWER UNIT (TYP)
AIR COMPRESSOR
OUTLINE OF MAT FOUNDATION AND PIPE ENCASEMENT
48" UW (8) HV-021
60" UW (8) 6" UW (8)
TO AND FROM OLV PL
48" UW (8) TO OLV R
STR-1
36" UW (8)
STRAINER
STR-2 STRAINER
PIPE ENCASEMENT,
36" UW (8)
A
36" BLIND FLANGE (CLASS 250)
HV-503
FUTURE FILL/DRAIN LINE IN FUTURE VALVE VAULT
B BALL VALVE (TYP)
SF-1 44’ 10"
SUMP PUMP (TYP)
SLANTING DISC CHECK VALVE (TYP) CONE VALVE (TYP)
SP-3
FCV-502 FILL/DRAIN FLOW CONTROL VALVE (TYP)
SP-2 SP-1
HV-204
HV-104
CV-303
CV-203
CV-103
FCV-302
FCV-202
FCV-102
36" UW (8)
36" UW (8)
P-300
P-200
SF-1
36" UW (8)
SUPPLY FAN (TYP)
C
*
P-100
SF-4
70’ 8"
GUTTER W/ GRATING (TYP)
HV-304
SF-2 PUMP FLOOR EL 795.0
Pl otScal e: 2:1
PUMP PAD FOR FUTURE PUMP
SF-5
PUMP (TYP)
D FCV-501
45’ 10"
HV-504 CV-505
36" BLIND FLANGE (CLASS 150)
BUTTERFLY VALVE (TYP)
54" UW (8)
54" UW (8)
54" UW (8)
SF-3 E
18" EPD (8) 54" UW (8)
36" UW (8)
HV-301
HV-201
HV-101
PIPE ENCASEMENT
F 10’ 6"
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
BUTTERFLY VALVE
SWING CHECK VALVE
48" UW (8) 6" CWR (24)
TO OLV WTP
13’-6"
102" UW (16) 28’-0"
28’-0"
28’-0"
53’-0"
Col orTabl e: bw.ctb
M ATCH LI NE
27’-0"
TO AND FROM OLV R
PIPE ENCASEMENT,
NOTES TO DESIGNER: 1. COAT ALL BURIED EXTERIOR SURFACES OF BURIED FLANGES WITH 15 MILS OF 2 PART EPOXY PAINT OR APPROVED EQUAL COATINGS
Fi l e: 002 Large HSC
Pl an.dgn
Model : Layout1
GENERAL PLAN
SCALE
SUBMITTED BY
WARNING 0
1
DESIGNED
DESIGNED
DRAWN
DRAWN
(PROJECT MANAGER’S NAME) SCALE
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
CHECKED
CHECKED
SHEET
LICENSE NO.
DATE
OLIVHAVEN PUMP STATION
EXAMPLE HORIZONTAL SPLIT CASE PUMP STATION
AND OLV8FCF PROJECT
MECHANICAL
M-5
PLAN (COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
Job No.
Pl ot Date: 15-SEP-2011 16:01
F
E
D
C
B
User: tayvaz
EXHAUST ACOUSTIC LOUVERS
A
EXHAUST ACOUSTIC LOUVERS
HOIST CENTER LINE HOIST CENTER LINE
CR-1
BRIDGE CRANE
6’-10"
6’-10"
6’ 6"
M AXI M UM
CRANE STOP BLOCK CRANE STOP BLOCK
BRIDGE CRANE CAT WALK
PLATFORM TO BRIDGE CRANE CAT WALK (SHOWN OUT OF SECTION)
24’ 9"
Pl otScal e: 2:1
MCC/VFD BEYOND PIPE WALL THICKNESS 0.5" EPOXY LINED AND COATED STEEL PIPE TEST PRESSURE = 250 PSI
PIPE WALL THICKNESS 0.5" EPOXY LINED AND COATED STEEL PIPE TEST PRESSURE = 150 PSI
2" SW (24) AIR DUCT SUPPORT
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
M-111
SLEEVE PIPE OPENING METHOB "B"
TIT-805 1" AVAR (TYP)
CABLE RACKS
FL EL 809.0
M-804
GR EL 808.5 +-
STAIRWAY TO PUMP ROOM
GR EL 808.5
2" V (24) P-300
M-160
INSULATING FLANGE
INSULATING FLANGE
* PUMP
36" COUPLING WITH HARNESS SET
EL 806.0
2" AIR VENT TYP 4 PLACES
END OF MORTAR COATING 6" FROM WALL
FROM PUM P ROOM FLOOR TO TOP OF PLATFORM
34’ 0" CONTROL ROOM
MI NI M UM HOOK LI FT TO PUM P FLOOR
BRIDGE CRANE CAB OPERATED TYPE
MORTAR LINED
M-160
END OF MORTAR COATING 6" FROM WALL
M-821
EPOXY LINED
EXIST GR EL 800 +
CL EL 799.50
CL EL 799.0
(CONTRACTOR SHALL VERIFY ACTUAL DISCHARGE PIPING CENTERLINE ELEVATION FROM OWNER FURNISHED PUMP EQUIPMENT REQUIREMENTS PRIOR TO PIPING AND VALVE INSTALLATION)
FL EL 795.0 MAT FOUNDATION AND PIPE ENCASEMENT
Col orTabl e: bw.ctb
M-139
PIPE SUPPORT MAX. 4’ SPACING (TYP)
102" UW (8) 54" UW (8)
M-109
PIPE SUPPORT
FCV-302 PUMP BASE
ADJUSTABLE PIPE SUPPORT
M-109A 54" BUTTERFLY VALVE
78" UW (8)
4" FLANGED BALL VALVE W/ BLIND FLANGE
HV-301
Model : Layout1
1" PA (7) MAT FOUNDATION AND PIPE ENCASEMENT SEE STR DWG (TYP)
2" SW (24) 4" UW (24)
1" SW (24)
CONE VALVE OPERATOR SUPPORT PER VALVE MANUFACTURER’S RECOMMENDATIONS
36" UW (8) VALVE SUPPORT (TYP)
M-193
TO PUMP SEAL WATER
M-196
VALVE SUPPORT (TYP)
M-156A
36" BALL VALVE
M-900
M-109A
ADJUSTABLE PIPE SUPPORT 54" COUPLING WITH HARNESS SET
HV-304
36" CONE VALVE
PIPE SUPPORT (TYP)
M-102
M-192 CV-303 36" SLANTING DISC CHECK VALVE
54" FLANGED COUPLING ADAPTER WITH HARNESS SET 2" FLANGED BALL VALVE W/ BLIND FLANGE
45’-10"
Secti on 1.dgn
90’-8"
SECTION
Fi l e: 002 Large HSC
SCALE:
SCALE
1
DESIGNED
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
DRAWN
CHECKED
SHEET
DESIGNED
(PROJECT MANAGER’S NAME) SCALE
*
SUBMITTED BY
WARNING 0
A
LICENSE NO.
DATE
DRAWN
CHECKED
OLIVHAVEN PUMP STATION
EXAMPLE - LARGE HORIZONTAL SPLIT CASE PUMP STATION
AND OLV8FCF PROJECT
MECHANICAL SECTION
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
2
EXAMPLE DRAWINGS MECHANICAL – LARGE VERTICAL NON-CLOG PUMP – PUMPS CLOSE COUPLED TO MOTOR Mechanical Plan Mechanical Section 1 Mechanical Section 2
This page left intentionally blank
CONCRETE UTILITY TRENCH. SEE CIVIL SHEETS FOR CONTINUATION
3" PRW (1)
3" HWS (1)
3" HWR (1)
26’-5"
14’-0"
14’-0" 2" YW (1)
2" PI (1) VENT, TYP
42" PI (8)
"PRW(1)
M-102
PIPE SUPPORT
1" PW (1)
TYP
WET WELL
TYP
ACCESS HATCH
N1-SLG1
Pl ot Date: 15-SEP-2011 16:10
D
D
N2-M-3
PIPE SUPPORT TYP
2" PRW (1)
6" SD (12)
VFD ROOM
N2-M-3
1 1/2" H/B-3 M-839
M-102
N2-RWP3
FROM SCREEN FACILITY
1 " PW(24)
2" YW (1)
SEAL WATER PANEL, SEE NOTE 2
2 " YW(1)
N2-RWP2 N2-PV1 N2-RWP1
TO SCREEN FACILITY N2-RWP2-GV1 N2-RWP1-GV1
C
17’ -0"
N2-M-3
FD, TYP
N2-RWP2 N2-RWP1
N2-RWP3-GV1
DISMANTLING JOINT TYP OF 6
N2-RWP3 N2-RWP2-CV N2-RWP1-CV
17’ -9"
N2-RWP2-GV2 N2-RWP3-CV N2-RWP1-GV2 CO/ VTR
N2-GV3
N2-RWP3-GV2
M-110
6" SD (12)
CO
48" PI (8)
TYP METER BYPASS
6" SPD (26) ROUTE TO SCREEN INFLUENT CHANNEL M
1" PRW (1) TO N1-SMP1
Col orTabl e: bw.ctb Model : N2-M-1
1 1/2" PRW(1) TO DISINFECTION
(SEE SHEET C-8 FOR
Fi l e: Large Non Cl og DP cose coupl ed pl an.dgn
C
N2-SBMP2
4’ -6"
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89. pen Pl otScal e: 10.666667:1 User : tayvaz
N2-SBMP1
CO/ VTR
N2-M-3
1" H/B-3 2" PI (1)
6" SD (12) M-110
B
6" PI (8)
A
N2-M-2
FROM N2-CAV
N2-M-2
N2-GV1 TYP
3" SD (12)
12’-8"
ROOF DRAIN
48" PI (8) ROUTE TO NEW
N2-FLM
48" PI (8)
FROM HEADER DRAIN ABOVE
NF-PW-BV7
M-839
15’-6"
3" SD (12)
3’-3"
OVERFLOW ROOF DRAIN
AERATED GRIT BASINS
26’-10"
3" SD (12)
B
OVERFLOW ROOF DRAIN
N2-M-2
PUMP ROOM FLOOR PLAN
CONTINUATION)
3’-6"
3" SD (12)
A
OVERFLOW ROOF DRAIN
N2-M-2 3" SD (12)
N2-GV2
ROOF DRAIN
3" SD (12) ROOF DRAIN
48" PI (8)
"=1’-0" NOTES: 1 PROVIDED YARD WATER HOSE BIBBS WITH HOSE RACK. HOSE BIBBS ARE LOCATED IN THE PUMP ROOM AND ONE NEAR THE WET WELL ACCESS HATCH.
GROUND FLOOR PLAN
4 ROUTE SEAL WATER DRAIN THE NEAREST FLOOR DRAIN.
"=1’-0"
5 ROUTE ALL FLOOR DRAINAGE TO DRAINAGE SUMP AT A" PER FT MINIMUM SLOPE.
2 PROVIDED RACK MOUNTED PUMP SEAL WATER CONTROL PIPING PER DETAIL M-826 DETAIL ON SHEET GM-7.
6 ROUTE ROOF DRAINS THE THE NEAREST STORM DRAIN, SEE CIVIL SHEETS. 3 ROUTE A " PRW (24) LINE TO EACH SEAL WATER PANEL AND THE PUMP SEAL WATER CONECTION. COORDINATE SIZE AND LOCATION WITH APPROVED PUMP SHOP DRAWINGS.
FINAL
CONSTRUCTION RECORD DRAWING This record drawing has been prepared,
WARNING 1
furnished by others to the preparer who is not responsible for any inaccuracies, errors or omissions
BY
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
B GRAVETTE DRAWN
DATE
D PATRICK FIELD BOOKS
which may have been incorporated into the document as a result
5/20/05 DESIGNED
entirely or in
part on the basis of unverified information compiled and
DATE
SCALE
CONSTRUCTION CHECKED
0
NO
R E V I S I O N
DATE
APPD
DRAWING NAME
CITY OF TACOMA
3/16"=1’-0" CHECKED
S LACY PROJECT NAME
DEPARTMENT OF PUBLIC WORKS
N2-M-1
CTP UPGRADE AND EXPANSION PHASE III NEW INFLUENT PUMPING STATION PUMP LEVEL AND GRADE LEVEL PLANS
SHEET NO.
SHEET
OF
N2-HST1
Pl ot 5-SEP-201 1 6: 1 0 Pl ot Dat Date: e: 1 1 5-SEP-201 11 1 6: 1 0
N2-HST1
N2-GV1 N2-GV2 FABRICATED PIPE SUPPORT FABRICATED PIPE SUPPORT
6" PI (8) FROM N2-CAV AND HEADER DRAIN EL 14.85
EL 14.85
48" PI (8)
Pl otScal e: 10.666667:1
EL 11.00
EL 11.00
N2-RWP3
N2-RWP1
48" PI (8)
2" PI (1)
2" PI (1)
N2-GV3
VENT
VENT 2" MANUAL PLUG VALVE, TYP
RACK MOUNTED SEAL WATER PIPING, TYP
2" ARV
3/4" PRW (1) 2" MANUAL PLUG VALVE
N2-RWP3-CV
2" ARV
6" SPD (26)
S
S
G
G
N2-RWP3-GV1 EL -5.39
S
STRAIGHTENING VANES
EL -5.39
S
6" HAND HOLE 6" HAND HOLE STRAIGHTENING VANES
EL -9.25 42" PI (8)
42" DISMANTLING JOINT, TYP
EL -13.31
EL -13.31
N2-RWP1-GV2
7" DIA TUBE WELDED TO SUCTION FLARE "
42" PI (8)
N2-RWP3-GV2
2 GM-8
1
EL -21.80
N2-RWP1-CV
PUMP MOUNTING BASE
7" DIA TUBE WELDED TO SUCTION FLARE
PROVIDE CONCRETE VALVE SUPPORT
1
2 GM-8
EL -21.98
PUMP MOUNTING BASE PROVIDE CONCRETE VALVE SUPPORT
2’-2" 1
1
EL -23.08
M-140
"
1
6" HAND HOLE, TYP GROUT FILL
1’ -5
1
1
EL -23.25
1’ -6"
EL -23.25
1’ -0"
EL -19.32
1
M-140
CROWN PLATE 6" HAND HOLE, TYP
TYP
Model : N2-M-2
Col orTabl e: bw.ctb
2" MANUAL PLUG VALVE
48" PI (8)
N2-RWP1-GV1
2’ -2
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89. pen User : t ayvaz
3/4" PRW (1)
M-112
2" MANUAL PLUG VALVE, TYP
M-110
42" DISMANTLING
M-112
6" SD (12)
JOINT, TYP
CROWN PLATE
2" MANUAL PLUG VALVE, TYP
6" PI (26)
GROUT FILL
N2-PV1
SECTION
6" SD (12)
B
Fi l e: Large Non Cl og DP cl ose coupl ed sec 1.dgn
N2-SP2 SCALE: "=1’-0"
N2-M-1
NOTES:
N2-SP1
1 SEE SHEETS N2-I-1 THROUGH N2-I-3 FOR ADDITIONAL PIPING APPURTENANCES.
SECTION
2 PROVIDE RACK MOUNTED PUMP SEAL WATER CONTROL PIPING PER DETAIL M-826 DETAIL ON SHEET GM-7.
SCALE:
A N2-M-1
3 ROUTE A 3/4" PRW (1) LINE TO EACH SEAL WATER PANEL AND THE THE PUMP SEAL WATER CONECTION. COORDINATE SIZE AND LOCATION WITH APPROVED PUMP SHOP DRAWINGS. 4 ROUTE SEAL WATER DRAIN THE NEAREST FLOOR DRAIN. FINAL FINAL
CONSTRUCTION RECORD DRAWING This record drawing has been prepared, entirely or in part on the basis of unverified information compiled and furnished by others to the preparer who is not responsible for any inaccuracies, errors or omissions which may have been incorporated into the document as a result
WARNING
DATE DATE
SCALE SCALE
CONSTRUCTION CONSTRUCTION CHECKED CHECKED
0
1
5/20/05 DESIGNED DESIGNED
BY BY
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
B GRAVETTE DRAWN DRAWN
DATE DATE
D PATRICK FIELD BOOKS BOOKS FIELD
NO NO
R E E V V I I S S I I O O N N R
DATE DATE
APPD APPD
DRAWING NAME NAME DRAWING
CITY OF TACOMA
3/16"=1’-0" CHECKED CHECKED
S LACY PROJECT NAME NAME PROJECT
DEPARTMENT OF PUBLIC WORKS
N2-M-2
CTP UPGRADE AND EXPANSION PHASE III NEW INFLUENT PUMPING STATION SECTIONS - 1
SHEET NO. NO. SHEET
SHEET SHEET
OF OF
3" SD (12) OVERFLOW ROOF DRAIN
3" SD (12)
Pl ot Date: 15-SEP-2011 16:10
OVERFLOW ROOF DRAIN
3" SD (12) ROOF DRAIN
3" SD (12) ROOF DRAIN
3’-7"
30’-7" N2-FLM-GV2 N2-FLM-GV1 3" HWS (1)
N2-CAV
3" HWR (1)
N2-CAV-BV1
N2-FLM
2" YW (1)
3" SD (12) 2" PI (1)
3" PRW (1)
OVERFLOW ROOF DRAIN
DRAIN
VFD ROOM
3" SD (12) ROOF DRAIN
M-113
TYP
EL 11.00
TYP
EL 11.00
M-101 2" PI (1)
EL 5.91
12" DIA FRP ODOR CONTROL DUCT
VENT BEYOND, TYP
SCREENING
6" PI (8)
EL 1.00
TO WET WELL
FACILITY
48" PI (8)
16’-3"
WET WELL
6" PI (8) FROM N2-CAV AND UPPER HEADER DRAIN
EL -5.13
EL -9.25
EL -9.50
EL -13.31
"
"
7"
EL -21.98 2" PI (1)
R
7’ -8
6 ’ 3 "
EL -19.32
GROUT
TOG
EL -21.82
DRAIN
TOG
EL -23.25
M-110
N2-RWP1
2’ -2
Model : N2-M-3
SECTION SCALE:
1’ -6"
N2-RWP2
"
N2-RWP3
Fi l e: Large Non Cl og DP cl ose coupl ed sec 2.dgn
EL -23.08
5’ -8"
Col orTabl e: bw.ctb
TYP
SIDE FILLET
N2-M-1
SCALE:
FINAL
This record drawing has been prepared, entirely or in part on the basis of unverified information compiled and furnished by others to the preparer who is not responsible for any inaccuracies, errors or omissions which may have been incorporated into the document as a result
CENTER SPLITTER
C
SECTION
CONSTRUCTION RECORD DRAWING
N1-SLG1
2’-0"
7’ -6"
5’-9"
N2-FLM-GV3
3 ’6
3’-0"
EL -13.31
R
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89. pen User : tayvaz
Pl otScal e: 10.666667:1
EL 14.85
WARNING
DATE
SCALE
CONSTRUCTION CHECKED
0
1
5/20/05 DESIGNED
BY
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
B GRAVETTE DRAWN
DATE
D PATRICK FIELD BOOKS
NO
R E V I S I O N
DATE
APPD
DRAWING NAME
D N2-M-1
CITY OF TACOMA
3/16"=1’-9" CHECKED
S LACY PROJECT NAME
DEPARTMENT OF PUBLIC WORKS
N2-M-3
CTP UPGRADE AND EXPANSION PHASE III NEW INFLUENT PUMPING STATION SECTIONS - 2
SHEET NO.
SHEET
OF
This page left intentionally blank
EXAMPLE DRAWINGS MECHANICAL – LARGE VERTICAL NON-CLOG PUMP – PUMPS w/ EXTENDED SHAFT AND FLYWHEEL Mechanical Plan Mechanical Section 1 Mechanical Section 2
This page left intentionally blank
This page left intentionally blank
EXAMPLE DRAWINGS MECHANICAL – SMALL HORIZONTAL SPLIT CASE Mechanical Plan Mechanical Section
This page left intentionally blank
A
9M 3
Pl otDat e: 01SEP2011 15: 18
MATCH LINE CONT. ON DWG 09M-2
TREATED WATER PANEL SEE NOTE 1
ELECTRICAL ROOM
User :t ayvaz
36" TW (11)
42" TW (11)
3 4"
6’-4"
6’-9"
13’-4 3/4 "
15’-0"
PA (7) FIELD ROUTE TO SURGE TANK
COMPRESSOR TANK
15’-0"
15’-0"
15’-0"
15’-0"
1’-0"
9’-7 1/4 "
10’ 0"
09 - AH - 300 MOUNT SWITCH WITH RESTRAINED HEAVY DUTY SPRING TYPE VIBRATION ISOLATORS
(TYP)
09 - AH - 310 COMPRESSOR 09 - V - 203
42" BLIND FLG 09 - V - 201 PIPE THIMBLE 09 - V - 250
09 - V - 240
09 - V - 260
09 - V - 230
09 - V - 220
M-122
09 - V - 210
(TYP)
STEM UP (TYP) 18’
24" BLD FLG (TYP)
(TYP) M-110 24" TW (11)
24" TW (11)
18" TW (11)
18" TW (11)
5 TON BRIDGE CRANE 24"x18" RED
09 - ME - 400
18"x14" RED 5’ MIN 2
18"x12" RED 09 - HP - 210
(TYP)
FUTURE PUMP PAD
12"x10" RED
09 - HP - 220
18"x10" RED 09 - HP - 240
09 - HP - 230
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
09 - V - 202
09 - V - 231
09 - V - 242
09 - V - 232
09 - V - 221 C
M-109
09 - V - 212
09 - V - 222
18" TW (11)
18" TW (11)
12" TW (11)
4’ 2"
36" BLIND FLG STEM HORIZ. HW UP (TYP)
12" TW (11)
4 ’ -1 0 "
19’ 0"
FIELD ROUTE TO COMPRESSOR
09 - SOV - 351
M-116 09 - SOV - 353 NOTES: 3 4"
M odel : Unt i t l ed Sheet Col or Tabl e: bw. ct b Fi l e: 002 HSC Pl an1. dgn
09 - V - 241
9M 3
Pl ot Scal e: 2: 1
09 - V - 262
(TYP)
14’
09 - V - 211
09 - V - 252 18" BLD FLG (TYP)
PA (7)
1. FIELD ROUTE DRAIN PIPING TO NEAREST DRAIN HUB
09 - TK - 350
NOTES TO ENGINEER: SURGE TANK
2. CONFIRM PUMP TO PUMP DIMENSION PROVIDES MINIMUM CLEARANCE AS APPROVED BY CLIENT MAINTAINANCE STAFF. PUMP GUIDE PROVIDES GUIDANCE 4’-3" B 9M-3
SCALE
WARNING 0
SCALE
A REV
06/30/09 DATE
GUIDE BY
DESCRIPTION
1 2
PROJECT 1
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
DESIGNED
DESIGN
DRAWN
DRAWN
CHECKED
CHECKED
SHEET
* *
HIGH SERVICE PUMP STATION
*
MECHANICAL
*
PLAN
9M-1 Job No.
Pl otDat e: 01SEP2011 15: 18
3 4"
PA (7)
VACUUM RELIEF VALVE 09-V-350 LE 350
SEE NOTE 1
9’ 0"
User :t ayvaz
09-TK-350
SURGE TANK 12’-0" 6’-0"
6’ 6"
12"x16" MANWAY
10"
2" DRAIN
09-V-350 FOUNDATION DESIGN BY SUBCONTRACTOR PER MANUFACTURER RECOMMENDATION
3 4"
09-ME-400
12" TW (11)
PA (7)
SECTION
5 TON BRIDGE CRANE
B 9M-1
ELECTRICAL ROOM (TYP)
M-110 18" SILENT CHECK 18"x14" RED PIPE CLAMP (TYP)
24"x18" RED
10"x18" RED
24" BUTTERFLY VALVE STEM UP (TYP)
18" BUTTERFLY VALVE
09-V-355 09-AH-300
6’-5" 6’ 6"
18" TW (11)
Pl ot Scal e: 2: 1
6’ 0"
5’ 10"
8’-6"
4’-6"
24" TW (11)
OSHA LADDER
PA (7)
42" TW (11)
36" TW (11)
5’-0" SUCTION HEADER
DISCHARGE HEADER
(TYP)
2’ 0"
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
M-109
SECTION
A 9M-1
09-V-350
12" TW (11)
36 TW (11)
M odel : Layout Col or Tabl e: bw. ct b Fi l e: 002 HSC Sect i on 1. dgn
3 4"
2’ 8 3/ 4"
COMPRESSOR TANK
FF 15’-0"
VACUUM RELIEF VALVE
NOTES:
SECTION
C 9M-1
1. SURGE TANK VENDOR SUPPLIED PACKAGE PIPING AND APPURTENANCES SHALL BE DESIGNED AND SUPPLIED BY MANUFACTURER 2. ALL FITTINGS TO BE FLANGED
SCALE
WARNING 0
SCALE
A REV
07/01/09 DATE
GUIDE BY
DESCRIPTION
1 2
PROJECT 1
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
DESIGNED
DESIGN
DRAWN
DRAWN
CHECKED
CHECKED
SHEET
* *
HIGH SERVIVE PUMP STATION
*
MECHANICAL
*
SECTIONS
9M-3 Job No.
EXAMPLE DRAWINGS MECHANICAL – SUBMERSIBLE NON-CLOG PUMP
Mechanical Plan I Mechanical Plan II Mechanical Section I Mechanical Section II
This page left intentionally blank
Pl ot Date: 01-SEP-2011 15:05 User: tayvaz
7’-0" (TYP)
16" FM (26)
Pl otScal e: 1.99992:1
(TYP)
B 4
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
P-5
P-4
P-3
P-2
BAFFLE WALL
HATCH ABOVE
Col orTabl e: bw.ctb
WET WELL
M-902
A
3
54" SS (11)
Model : Layout1 Fi l e: 005 sub noncl og pum p-wetpi t-PLAN1.dgn
P-1
GENERAL PLAN
SCALE
SUBMITTED BY
WARNING 0
1
DESIGNED
DESIGNED
DRAWN
DRAWN
(PROJECT MANAGER’S NAME) SCALE
A
10/28/09
REV
DATE
GUIDE BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
CHECKED
SHEET
CLEAN WATER SERVICES
CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
LICENSE NO.
DATE
DATE
EXAMPLE - SUBMERSIBLE NON - CLOG PUMP STATION
LOWER TUALATIN
- WET PIT
PUMP STATION
MECHANICAL PLAN
1
Pl ot Date: 01-SEP-2011 15:05
4
-0 "
20" FM (26) ’
ROUTE CONDENSATE DRAIN
20" FM (26)
BETWEEN CONCRETE WALL FORCEMAIN 1,
AND BRICK VENEER, TERMINATE PIPE THRU BOTTOM OF VENEER
C EL 114.36 L PIPE SUPPORT,
20" FM (26)
OMIT U-BOLT WHEN
(TYP)
USED AT FLGS
M-902
C EL 114.36 L
M-108
(TYP)
INSTALL TWO JOINTS WITHIN 5 FEET OF
45-DEG BEND
ELBOW
W/ RESTRAINED JOINTS (TYP)
20" FM (26)
(TYP)
M-907
20" FM (26)
FORCEMAIN 2, C L EL 114.36
C EL 113.00 L 90-DEG BEND, RESTRAINED JOINTS,
4’-0"
PV-6
2’-6"
PV-7
5’ 6"
User: tayvaz
(2) 11.25-DEG VERTICAL BENDS W/ RESTRAINED JOINTS 5’-0"
20" FM (26)
90-DEG BEND, FLG X RESTRAINED
2’-0"
C EL 113.00 L
INSULATED FLANGE FOR CATHODIC
HD
HD
HD
HD
PROTECTION SYSTEM
9’ 10"
2’ 0"
JOINT, ROTATE UP FROM HORIZONTAL
C-905
PV-3
PV-9
PV-5 20" FM (26)
PROTECTION SYSTEM
HD
FD
8" FM (26)
PV-1 FD
FD
FD
(TYP)
16" FM (26)
M-904
(TYP)
M-108
(TYP)
CKV-5
CKV-4
CKV-3
CKV-2
BLIND FLANGE C EL 122.50 L Pl otScal e: 1.99992:1
C-905
4" FM (26)
PV-2
PV-4
FD
1’-0"
INSULATED FLANGE FOR CATHODIC
7’-0" (TYP)
PV-8
BY-PASS
CKV-1
4" SEWAGE COMBINATION AIR VALVES
PIPE SUPPORT
HATCH ABOVE
PRESSURE
M-140
GAUGE (TYP)
I-903
B
ME-2 ME-1
4
NOTE 5
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
NOTE 5 1’-0"
B-1
HB-3
B-2
LSHHH-1 WET WELL BELOW
BLIND FLANGE, TYP BOTH SIDES OF SPOOL,
LSHH-1
PIPE SUPPORT (TYP)
M-102
I-900
LSH-1
C L EL 122.50
LT-2 I-901 LT-3 3" D (16)
BF-1
BF-2
EMBED IN CONC SLAB,
(TYP)
M-116
ROUTE TO WET WELL WH-1, BELOW SINK
1-1/2" NPW (24) 1/2" BACKFLOW WCO
Col orTabl e: bw.ctb
SS
PREVENTER
1-1/2" PW (24) HB-3
1/2" PW (24) 1 1- 2" BACKFLOW PREVENTER
METHOD ’A’
M-111 (TYP) HOSE BIBB AND RACK (TYP)
NOTES :
M-824
2" PW (24)
M-825 1. THIS ENTIRE LEVEL IS CLASSIFIED AS A CORROSIVE AREA. ALL PIPE SUPPORTS SHALL BE CONSTRUCTED OF TYPE 316 STAINLESS STEEL.
C EL 118.50 L
Model : Layout1 Fi l e: 005 sub noncl og pum p-wetpi t-PLAN2.dgn
ROTATE DOWN FROM HORIZONTAL
1-1/2" PW (24)
INSTALL TWO JOINTS WITHIN 4 FEET OF FACE OF WALL
CAP ON INSIDE FACE OF WALL, C EL 118.50, L
2. ALL FORCEMAIN PIPING, INCLUDING MECHANICAL COUPLINGS SHALL BE RESTRAINED 3. SLOPE ALL DRAIN LINES 1/4" PER FOOT MINIMUM TO WET WELL.
12" FA(13)
A
54" SS (11)
3
PLAN
SCALE
SUBMITTED BY
WARNING 0
1
DESIGNED
DESIGNED
DRAWN
DRAWN
(PROJECT MANAGER’S NAME) SCALE
A
11/19/09
REV
DATE
GUIDE BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
CHECKED
SHEET
CLEAN WATER SERVICES
CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
LICENSE NO.
DATE
DATE
EXAMPLE - SUBMERSIBLE NON - CLOG PUMP STATION
LOWER TUALATIN
- WET PIT
PUMP STATION
MECHANICAL FLOOR PLAN
2
Pl ot Date: 01-SEP-2011 15:05
RUNWAY BEAM
MAINTENANCE RUNWAY BEAM
FOR ME-2
RUNWAY BEAM
BAY
FOR ME-1
User: tayvaz
FOR ME-1 AND ME-2
SADDLE ON
PV-3
HIGH HOOK FLANGED
8" FM (26)
COUPLING
ME-2
ADAPTER
BRIDGE CRANE
20" FM (26) 9’ 9"M I N
CKV-3
20" FM (26)
EL 113.00
C EL 114.36 L
EL 110.17 FD LIFTING CHAIN,
M-902
TEATHER TO SIDE
Pl otScal e: 1.9992:1
12" FA (13)
OF OPENING
16" FM (26) OMIT U-BOLT WHEN USED AT FLANGES (TYP)
54" SS (11)
EL 103.17, NOTE 2, 4
(TYP EACH
EL 102.29, NOTE 2, 4
TRENCH)
M-108
M-904
INV EL 104.00 EL 101.25, NOTE 2, 4
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
HWL 99.14, NOTE 2, 4
LWL 96.67, NOTE 4
WET WELL M-902
16" FM (26) INV EL 95.54
EL 88.40, NOTE 3, 4
P-3
CONCRETE
NOTES OT DESIGNER:
FILLET, SEE STR DWGS
1. ALL FORCEMAIN PIPING, INCLUDING MECHANICAL COUPLINGS SHALL BE RESTRAINED
OPENING Col orTabl e: bw.ctb
2. ELEVATIONS INDICATE THE BALL FLOAT SETPOINT ELEVATION FOR LSH-1, LSHH-1, AND LSHHH-1
16"X12" ECCENTRIC
3. ELEVATIONS INDICATE THE LOW LEVEL CUT OFF ELEVATION
REDUCER
EL 81.40
FOR LSL-2 AND LSL-3 4. WATER SURFACE ELEVATIONS SHALL BE PER HYDRAULIC INSTITUTE GUIDELINES AND PUMP MANUFACTURER
Fi l e: 005 sub noncl og pum p-wetpi t-SEC1.dgn
Model : Layout1
RECOMMENDATIONS WITH REGARDS TO NPSH CRITERIA
SECTION
A 1 2
SCALE
SUBMITTED BY
WARNING 0
1
DESIGNED
DESIGNED
DRAWN
DRAWN
(PROJECT MANAGER’S NAME) SCALE
A
11/19/09
REV
DATE
GUIDE BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
CHECKED
CHECKED
SHEET
CLEAN WATER SERVICES
(COMPANY OFFICER’S NAME)
LICENSE NO.
LICENSE NO.
DATE
DATE
EXAMPLE - SUBMERSIBLE NON - CLOG PUMP STATION
LOWER TUALATIN
- WET PIT
PUMP STATION
MECHANICAL SECTION-II
3
Pl ot Date: 01-SEP-2011 15:06
EQUIPMENT ROOM
C 4
MAINTENANCE User: tayvaz
4" SEWAGE COMBINATION
BAY
RUNWAY
AIR VALVE (TYP OF 2)
BEAM BLIND FLANGE
4" FM (26) (TYP)
EL 122.50
M-104
8" FM (26)
C L EL 120.50
8" FM (26) 20" FM (26)
(TYP)
M-902
C L EL 116.00
ME-1
M-104
8X4 REDUCER
4" FM (26)
(TYP)
20" FM (26)
BYPASS BRIDGE CRANE
20" FM (26)
PRESSURE
PV-7
20" FM (26)
GAUGE PV-9
(TYP)
PV-6
EL 113.00 INSULATED FLANGE FOR CATHODIC
Pl otScal e: 1.9992:1
EL 110.17
PROTECTION SYSTEM
C-905
16" FM (26) M-116
(TYP)
SEE NOTE 2 HWL 99.14
3’-9"
(TYP)
5’-8"
7’-0"
EL 124.75
(TYP)
LWL 96.67
UNDERSIDE OF Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
CONC BEAM TO WET WELL
4" SEWAGE COMBINATION
4" FM (26)
8 1/2"
AIR VALVE (TYP OF 2)
4" PLUG
C L EL 120.50
VALVE (TYP) EL 119.34
EL 81.40 8X4
P-5
REDUCER
P-4
P-3
P-2
P-1
2’-0" Col orTabl e: bw.ctb
8" FM (26)
(TYP)
M-104
C L EL 116.00 FROM HEADER
INSIDE FACE OF CONC WALL
EL 110.17
Fi l e: 005 sub noncl og pum p-wetpi t-SECI I .dgn
Model : Layout1
NOTES : 1. ALL FORCEMAIN PIPING, INCLUDING MECHANICAL COUPLINGS SHALL BE RESTRAINED. 2. WATER SURFACE ELEVATIONS SHALL BE PER HYDRAULIC INSTITUTE GUIDELINES AND PUMP MANUFACTURE RECOMMENDATIONS.
SECTION
C SECTION
-
B 1 2
SCALE
SUBMITTED BY
WARNING 0
1
DESIGNED
DESIGNED
DRAWN
DRAWN
(PROJECT MANAGER’S NAME) SCALE
A
11/19/09
REV
DATE
GUIDE BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
CHECKED
CHECKED
SHEET
CLEAN WATER SERVICE
(COMPANY OFFICER’S NAME)
LICENSE NO.
LICENSE NO.
DATE
DATE
EXAMPLE - SUBMERSIBLE NON - CLOG PUMP STATION
LOWER TUALATIN
- WET PIT
PUMP STATION
MECHANICAL PLAN
4
EXAMPLE DRAWINGS MECHANICAL – VERTICAL TURBINE CAN PUMP Mechanical Plan Mechanical Section
This page left intentionally blank
Pl otDat e: 01SEP2011 15: 03
TO DEEP INJECTION WELL
24" RCW (11)
TO ANALYZER SHED, SEE SHT. 6M-21
36" MOTORIZED B’FLY VALVE
12" RCW (11)
C-913 SA (16)
36" MOTORIZED B’FLY VALVE
C-913
3 4"
SERVICE TAP
M
3 4"
RECLAIMED TANK REFILL
C-913
24" MOTORIZED B’FLY VALVE
36" RCW (11)
M-923
36"x16" TEE
M A
1" AVAR VALVE, TYP
6M-12 36" RCW (11)
36" MJ PLUG
5’-0"
3
M-922
EX 1" AVAR
REMOVE EX. PLUG AND CONNECT TO EX. 36" RCW
36" RCW (11) EX 18" EXPANSION COUPLING, TYP
2" SERVICE TAP
EX 18" B’FLY VALVE, TYP
(TYP)
M-923
16" TAPPING SLEEVE AND VALVE
TO REUSE DISTRIBUTION SYSTEM
7’ 2"
User :t ayvaz
TO SANITARY 4 SEWER (TYP)
M-804
TO REUSE DISTRIBUTION SYSTEM
36"x24" TEE
PIT-169
G
18" EXPANSION COUPLING, TYP W/HARNESS SET
18" RCW (11)
06P165
06P164
06P163
EX PLANT JOCKEY PUMP EX RECLAIMED WATER PUMP, TYP
7’-6"
7’-6"
4’-0"
S
7’-6"
FUTURE PUMP
S
7’-6"
M-136 MOUNTING BASE EX 24" B’FLY VALVE
NEW ACCESS DRIVE, SEE CIVIL
NEW PUMP STATION
TYP OF 5
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
EMERGENCY EYEWASH WITH FLOW SWITCH
C-120
M-910
4’x6’ CONC SPLASH PAD
M-803
2" UW (16) SEAL WATER
NEW CHEMICAL INJECTION VAULT
24" RCW (11) NEW ACCESS DRIVE, SEE CIVIL
TYP
NOTES: 1. FIELD ROUTE SEAL WATER FROM SEAL WATER PANEL TO EACH PUMP.
24" B’FLY VALVE EXISTING CHEMICAL INJECTION MANHOLE, DEMOLISH EXISTING CHEMICAL PIPE AND ABANDON IN PLACE
24" LONG SPOOL, TYP
2. PROVIDE SEAL WATER DRAIN FOR EACH PUMP. FIELD ROUTE TO FINISHED GRADE.
NOTES TO ENGINEER:
21’-0" NTS
M odel : Layout Col or Tabl e: bw. ct b Fi l e: 003 Ver t i calTur bi ne Can Pl an. dgn
EXISTING PUMP STATION
24" RCW (11)
25’ 7"
M-911
SURGE TANK SEE SHEET 6M-13
32’-0"
11’-0"
FI ELD VERI FY
Pl ot Scal e: 2: 1
38’-0"
TO PLANT UTILITY WATER SYSTEM
10"x18" REDUCER
VERTICAL PUMP MOUNTING BASE, TYP 4’-0"
16" RCW (11)
EX PRESSURE GAUGE
4’ 9"
RECLAIMED WATER PUMP, TYP
EX 18" SWING CHECK VALVE, TYP
06P162
SEAL WATER PANEL
12" UW (11)
TYP
13’ 6"
14’ 0"
( FUTURE)
M-917
06P144
06P143
06P142
06P140
PRESSURE SWITCH AND PRESSURE GAUGE, TYP
06P141
18" SWING CHECK VALVE, TYP
M-135
18" RCW (26) 14"x18" REDUCER (TYP OF 4)
TYP
I-110
M
18" BLIND FLANGE
06P161
M-902
FI ELD VERI FY
3’ 7 1/ 4"
18" B’FLY VALVE, TYP
3. CONFIRM PUMP TO PUMP DIMENSION PROVIDES MINIMUM CLEARANCE AS APPROVED BY CLIENT MAINTAINANCE STAFF. PUMP GUIDE PROVIDES GUIDANCE 4. PIPE ALL ARV’S TO SANITARY SEWER
36" LONG SPOOL, TYP FROM RECLAIMED WATER STORAGE TANKS 1 2"
1
48" RCW (11) 48" SLEEVE COUPLING
36" SLEEVE COUPLING
WARNING 0
SCALE
REV
06/25/09 DATE
GUIDE BY
PLAN
PW (16)
SCALE
A
48" RCW (11)
48" LONG SPOOL, TYP
DESCRIPTION
1 2
PROJECT 1
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
DESIGNED
DESIGN
DRAWN
DRAWN
CHECKED
CHECKED
SHEET
* *
RECLAMIED WATER PUMP STATION
*
MECHANICAL
*
PLAN
DWG# Job No.
Pl otDat e: 01SEP2011 15: 03 User :t ayvaz
18"x10" CONCENTRIC REDUCER PRESSURE SWITCH AND PRESSURE GAUGE
I-110
18" SWING CHECK VALVE 18" EXPANSION COUPLING 18" B’FLY VALVE 1" AVAR VALVE S
RECLAIMED WATER PUMP
M-135
M-804
G
CL EL 12.00
CONCRETE EQUIPMENT BASE
FINISH GRADE EL 9.0 FF EL 9.25
2’ SQ CONC PAD ON GRADE
M-108
48" RCW (11)
PIPE SUPPORT, TYP
18" RCW (11)
24" RCW (11)
M-902
HARNESS SET CL EL 4.50
CL EL 4.25
36" RCW (11)
24" BURIED B’FLY VALVE WITH EXTENDED BONNET
TO SANITARY SEWER 4
PUMP CAN
Pl ot Scal e: 2: 1
M-803
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
PER PUMP MFR RECOMMENDATIONS
EL -4.50
3’-0" DIA
TYP SECTION
A
Fi l e: 003 Ver t i calTur bi ne Can Sect i on. dgn
M odel : Layout Col or Tabl e: bw. ct b
6M-11
SCALE
WARNING 0
SCALE
A REV
06/24/09 DATE
GUIDE BY
DESCRIPTION
1 2
PROJECT 1
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
DESIGNED
DESIGN
DRAWN
DRAWN
CHECKED
CHECKED
SHEET
* *
RECALIMED WATER PUMP STATION
*
MECHANICAL
*
PLAN
DWG# Job No.
EXAMPLE DRAWINGS MECHANICAL – VERTICAL TURBINE PUMP (CLEAR WELL) Mechanical Plan & Section
This page left intentionally blank
REFER TO CIVIL DWGS FOR GRADING REQUIREMENTS TO SET LENGTH
3’-0" Pl otDat e: 01SEP2011 15: 04
MINIMUM
A
B
---
--CLEARWELL
18’’ FLAP VALVE 5’-0"
18" OF (11) (TYP)
1
(TYP)
EL 17.00 2’ 0"
MATCHLINE - SEE SHEET 6M-2
08-P-110
C L EL 15.0 +/-
08-P-130
08-P-120
FUTURE
FUTURE
08-P-140
08-P-150
GROUND EL 15.0’
MI NI M UM
6"
GROUND EL 13.5 +/-
FLAP GATE (TYP)
S-190
SPLASH PAD
FUTURE
User :t ayvaz
08-ARV-111
12"x 16" RED (TYP.)
08-ARV-121
08-ARV-131
08-ARV-141
PSH
PSH
PSH
PSH
110
120
130
140
FUTURE
FUTURE
PSH
08-V-125
08-V-135
FUTURE
150
FUTURE 08-V-115
SPLASH PAD
08-ARV-151
FUTURE
08-V-145
08-V-155
16" TW (11) (TYP)
08-V-116
M-902
08-V-126
08-V-146
08-V-136
08-V-156
HARNESS JOINT TYP
B
SECTION
36" BLIND FLANGE
-
8’-4" (TYP) 36" TW (11)
36" RESTRAINED COUPLING
AIR RELEASE VALVE
PLAN
M-804
08-V-131
08-P-130
PRESSURE INDICATOR/ PRESSURE SWITCH
PSH 130
CHECK VALVE BUTTERFLY VALVE
08-V-135
Pl ot Scal e: 2: 1
08-V-136
M-135
C L EL 18.67
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
EL. 17.00
16" TW (11)
36" TW (11)
GRADE = 14.5 CLEARWELL
HWL 12.00 C L EL 10.00 NOTES TO ENGINEER: MIN DISTANCE REQUIRED PER PUMP MANUFACTURER RECOMMENDATIONS
LWL 8.00
1. CONFIRM PUMP TO PUMP DIMENSION PROVIDES MINIMUM CLEARANCE AS APPROVED BY CLIENT MAINTAINANCE STAFF. PUMP GUIDE PROVIDES GUIDANCE 2. FLOW BAFFLE TO MEET HYDRAULIC INSTITUTE (H.I.) REQUIREMENTS
FLOW BAFFLE
PIPE SUPPORT
2
3. PIPE ALL ARV’S TO WET WELL
M-110
4. PROVIDE GROUT FOR BOTTOM SLOPE PER H.I. STANDARDS
M odel : Layout Col or Tabl e: bw. ct b Fi l e: 003 Ver t i calTur bi ne W W 1. dgn
M-136
5. PROVIDE SECTIONS FOR EASE OF REMOVING
EL 3.00 MIN DISTANCE REQUIRED PER PUMP MANUFACTURER RECOMMENDATIONS
VORTEX BREAKER
SECTION
A -
SCALE
WARNING 0
1 2
PROJECT 1
DESIGNED
DESIGN
DRAWN
DRAWN
* SCALE
A REV
06/18/09 DATE
GUIDE BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
CHECKED
CHECKED
SHEET
* EXAMPLE - CLEARWELL AND TRANSFER PUMPS
*
MECHANICAL
*
PLAN AND SECTION
DWG# Job No.
This page left intentionally blank
EXAMPLE DRAWINGS MECHANICAL –PLANT LIFT STATION Mechanical Plan & Section
This page left intentionally blank
Pl otDat e: 01SEP2011 15: 06
M-108
1
5’-0"
1" AVAR VALVE
M-902
1’-9" TO GRIT TANKS INFLUENT BOX
FIBERGLASS LADDER 4’ 4"
5’-0"
( TYP)
1’ 3"
16"x8" TEE, (TYP)
1 5’-0"
16" SLEEVE CPLG w/HARNESS SET
5
M-804
SUMP PUMP (TYP) 3’-6"
PIPE SUPPORT w/U-BOLT, (TYP)
16" BLIND FLANGE 16" FM (26) CL EL 2.56
8" PLUG VALVE (TYP) 8" SWING CHECK VALVE (TYP) 10-P-230
10-P-220
10-P-210
8" PLUG VALVE
10-P-200
8" FM (26) 16’ 0"
User :t ayvaz
FUTURE PUMP
M-803
6"
FLOW BAFFLE
6" CD (27)
2’ 0"
1’-0" 16" PD (26) FROM CLARIFIERS NO. 3,4,5 AND 6
M-116
3’x3’ ACCESS HATCH WITH FALL PROTECTION
1’-0"
FROM ODOR CONTROL
2’ 0"
6’ 4"
6"
8" PD (26) FROM ACTIVATED SLUDGE BASINS
2’ 0"
FROM TANK DRAINS
8" FLG’D CPLG ADAPTOR
4" DIA FLG’D PIPE, TYP OF 2
REMOVABLE GRATE COVERED OPENING
WALL PIPE
25’-0"
WALL PIPE (TYP)
M-116
A ---
PLAN AT ELEV. 5.00 A ---
PLAN AT ELEV. 10.00 16" FM (26)
Pl ot Scal e: 2: 1
REMOVABLE GRATING WITH FALL PRTECTION
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
C L EL 12.00
EL 10.00 FG 9.5
M-108
PIPE SUPPORT WITH U-BOLT, TYP
NOTES TO ENGINEER:
1. CONFIRM PUMP TO PUMP DIMENSION PROVIDES MINIMUM CLEARANCE AS APPROVED BY CLIENT MAINTAINANCE STAFF. PUMP GUIDE PROVIDES GUIDANCE
GUIDE RAILS 2. FLOW BAFFLE TO MEET HYDRAULIC INSTITUTE (H.I.) REQUIREMENTS 3. PROVIDE GROUT FOR BOTTOM SLOPE PER H.I. STANDARDS
16" WW (27)
4. PROVIDE SECTIONS FOR EASE OF REMOVING
M odel : Layout Col or Tabl e: bw. ct b Fi l e: 006 sm al lsub st at i on pl an and sec. dgn
8" FLANGED COUPLING ADAPTER
FLOW BAFFLE
5. PIPE ALL ARV’S TO WET WELL
PUMP LEVEL ELEVATIONS NON-SHRINK GROUT FILL
INV EL -3.4 8" FM (26)
EL -5.92
HWLALARM = -3.4 LAG 2 PUMP ON = -4.4 LAG 1 PUMP ON = -4.9 LEAD PUMP ON = -5.4 ALL PUMPS OFF = -5.9
6"x8" REDUCER
EL -7.58
TOP OF GROUT EL -7.4
SUMP PUMP 10-P-220
A
SECTION
---
SCALE
WARNING 0
SCALE
A REV
06/18/09 DATE
GUIDE BY
DESCRIPTION
1 2
PROJECT 1
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
DESIGNED
DESIGN
DRAWN
DRAWN
CHECKED
CHECKED
SHEET
* *
EXAMPLE
*
MECHANICAL
*
PLANT LIFT STATION
DWG# Job No.
This page left intentionally blank
EXAMPLE DRAWINGS MECHANICAL – CHOPPER PUMP Mechanical Plan Mechanical Section Instrumentation
This page left intentionally blank
CONCRETE BAFFLE WALL
M-919
T R U E
ACTIVATED SLUDGE BASIN
8" FA (18)
EFFLUENT CHANNEL
STN STL WALL PIPE
8"
2’-0" 1’-0"
SCUM WET WELL 2’-1"
2’-9"
M-113
1 " NPW (24)
1’ -6"
8" PD (26)
User: tayvaz
MOTORIZED STN STL M-217 SLIDE GATE
ACTIVATED SLUDGE BASIN
PLANT
EFFLUENT CHANNEL
1’ -6"
PLANT
1’ -6"
2’-0" WALL PIPE, MJxPE
T R U E
SPRAY NOZZLE, M-937 TYP, NOTE 1
SCUM WET WELL
2’-6"
1" NPW (24) 8" FA (31)
STILLING WELLS
1" NPW (24) (SPRAY SYSTEM) NOTE 3
2" SA5 (16)
A
A 1’-10"
2" SA4 (16)
4"
M-WCM-2 1’ -1"
1 " NPW (16)
1’ -10"
"
STILLING WELLS
3’ -8
M-918
PUMP GUIDE RAILS
9"
2’-9"
DRAINAGE SUMP, SEE CIVIL
2’-8"
2" SA3 (16)
PRECAST CONCRETE VALVE VAULT
4"
1’ -6"
Pl ot Date: 16-SEP-2011 08:17
1 ---
1’-0"
M-WCM-2
2" NPW (16)
2" SA5 (16)
SMP352
2" SA3 (16) 3-WAY PLUG VALVE WITH BLIND FLANGE, NOTE 2
SCUM PUMP
B
1 " NPW (16) 4’ -6"
SMP351
M-WCM-2
14" OF (19) SOLID SLEEVE COUPLING, TYP
FLOOR PLAN
18" FA (41) FUTURE FOUL AIR PIPE MOTORIZED STN STL SLIDE GATE
8" FA (18)
18"x45^ BEND
M-217
2" NPW (16)
1’ -6"
6"x4" REDUCER ACTIVATED SLUDGE BASIN
6"x4" TEE
EFFLUENT CHANNEL
6" S (19)
6"
11"
2’-11"
M-WCM-2 M-927
PORTABLE EQUIPMENT HOIST, TYP
11"
INTERMEDIATE PLAN
1 1/2" NON-FREEZE M-935 HOSE BIBB 1’-0"
B
4" S (30)
ACCESS COVERS, TYP
1" NPW (24) (SPRAY SYSTEM) NOTE 3
S
1’ -2" ELECTRICAL CONTROL PANEL
SCUM WET WELL
6" " CHAMFER, TYP
8" V (18)
A
8"
NO. 4 AT 6" O.C.
Fi l e: 008 Chopper Pum p - Pl an.dgn
STILLING WELLS
1’-8"
2’ -0"
M-WCM-2
1’ -6"
PLANT
18" HDPE PLUG
18"x8" TEE
Model : Defaul t
Col orTabl e: bw.ctb
2" SA4 (16) 4" S (30)
SCUM PUMP
T R U E
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
Pl otScal e: 5.333333:1
1’-1"
STRUCTURAL CONCRETE BAFFLE WALL
NO. 4 AT 12" O.C.
8"
4’-6"
M-917
4’ -6"
1 " NON-FREEZE YARD HYDRANT
DRILL AND EPOXY, 6" MIN EMBED
C-627
EXISTING FLOOR
GENERAL SHEET NOTES SECTION
30" WATERTIGHT MANHOLE LID AND FRAME
FRONT VIEW
CONCRETE BAFFLE WALL DETAIL NTS
1.
4 SPRAY NOZZLES REQUIRED FOR SPRAY SYSTEM. (2) OUTSIDE NOZZLES SHALL BE BETE MODEL MP281N. (2) INSIDE NOZZLES SHALL BE BETE MODEL NC0706K.
2.
3-WAY PLUG VALVE SHALL BE DEZURIK, COMBINATION ’O’ OR EQUAL.
3.
HEAT TRACE AND INSULATE ALL EXPOSED NPW PIPES.
1 VARIES
B
PRECAST CONCRETE VALVE VAULT
JOB NO: 1700665
M-WCM-2
ROOF PLAN DESIGNED BY:
DRAWN BY:
CHECKED BY:
APPROVED BY:
VERIFY SCALE 0
APPROVED BY
LICENSE NO.
DATE
SUBMITTED BY
LICENSE NO.
DATE
1/2
Denver 1
Colorado
ACTIVATED SLUDGE BASIN SCUM PUMP STATION - PLANS
IF THIS BAR DOES NOT MEASURE 1" SCALE:
ADJUST SCALES
REV.
DATE
BY
DESCRIPTION
ACCORDINGLY
DRAWING NO.:
" = 1’-0"
REV.
M-WCM-1
SHEET
OF
1
GENERAL SHEET NOTES 1.
4 SPRAY NOZZLES REQUIRED FOR SPRAY SYSTEM. (2) OUTSIDE NOZZLES SHALL BE BETE MODEL MP281N. (2) INSIDE NOZZLES SHALL BE BETE MODEL NC0706K.
2.
3-WAY PLUG VALVE SHALL BE DEZURIK, COMBINATION ’O’ OR EQUAL.
3.
HEAT TRACE AND INSULATE ALL EXPOSED NPW PIPES.
POPRTABLE M-927 EQUIP HOIST M-917 ELECTRICAL CONTROL PANEL
PIPE SUPPORT
1" NPW (16) SPRAY HEADER SPRAY NOZZLE, M-937 NOTE 1
8" V (18)
24"W x 42" H MOTORIZED STN STL SLIDE GATE 2’ -7"
User: tayvaz
Pl ot Date: 16-SEP-2011 08:17
24"W x 42" H MOTORIZED M-217 STN STL SLIDE GATE
M-217
6" V (16) SEE STRUCTURAL EL 4949.50
EL 4949.50
CL EL 4948.17
RECIRCULATION CONTROL HANDLES 8" FA (18)
1 " TO HOSE BIBB PRECAST CONCRETE VALVE VAULT
1" NPW (16) C-907
30" DIA WATERTIGHT MANHOLE LID
FG 4943.00
SPRAY HEADER
2" SA5 (16) INV 4938.58
6" V (16)
3’ -6"
EL 4943.50
FG 4943.00
2" SA4 (16)
Pl otScal e: 5.333332:1
INV 4938.58 VIC CPLG, TYP
2" SA3 (16) 1 " NPW (24)
INV 4938.58
1" NPW (24) 2" NPW (16)
GUIDE RAILS
EL 4941.50
3-WAY PLUG VALVE w/ BLIND FALNGE
6" S (19)
WALL PIPE, M-920 MJxVIC
8" FA (31)
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
CL EL 4937.67
STN STL WALL PIPE
CL EL 4937.67
INV 4937.42 EL 4936.50
M-113
4" S (30)
6"x4" TEE
INV 4935.50 6"x4" REDUCER
SOLID SLEEVE CPLG
4" S (30)
GUIDE RAILS
4" S (30)
18" FA (41) INV 4934.42 HWS EL 4930.62
HWS EL 4930.62 INV 4931.92
M-918
STILLING WELLS 36" ML (19) SOLID SLEEVE CPLG, TYP RECIRCULATION CONTROL HANDLES
M-919
WALL PIPE, MJxPE
14" OF (19)
JOB NO: 1700665
Fi l e: 008 Chopper Pum p - Secti on.dgn
Model : Defaul t
Col orTabl e: bw.ctb
GUIDE RAIL SUPPORTS LWS EL 4924.98
LWS EL 4924.98 INV 4926.00
EL 4925.00
EL 4925.00
M-919 8" PD (26)
WALL PIPE, MJxPE
INV 4920.33 EL 4919.67
EL 4919.67
1
S-171
CONCRETE BAFFLE WALL M-WCM-1
CONCRETE ENCASEMENT SMP352
SMP352
SMP351 SCUM PUMP
SECTION
SECTION
A
DRAWN BY:
B M-WCM-1
M-WCM-1
DESIGNED BY:
8" PD (26)
SCUM PUMP
SCUM PUMP
CHECKED BY:
APPROVED BY:
VERIFY SCALE 0
APPROVED BY
LICENSE NO.
DATE
SUBMITTED BY
LICENSE NO.
DATE
1/2
CITY OF FORT COLLINS UTILITIES 2008 MWRF IMPROVEMENTS
Denver 1
Colorado
ACTIVATED SLUDGE BASIN SCUM PUMP STATION - SECTIONS
IF THIS BAR DOES
1
REV.
051309
SRT
DATE
BY
DESIGN PACKAGE 4 - IFC DESCRIPTION
NOT MEASURE 1" SCALE:
ADJUST SCALES ACCORDINGLY
DRAWING NO.:
" = 1’-0"
REV.
M-WCM-2
SHEET
OF
1
DESCRIPTION
Pl otDat e: 16SEP2011 08: 17
KEY NOTES: 1
MOTOR STARTER PROGRAMMMED TO SHUT DOWN THE PUMP UPON ACTIVATION OF EITHER TEMPERATURE OR MOISTURE SWITCH TO RETAIN WARRANTY.
SUPERVISORY
CONTROL
DP HAND SMP351
DP
DI
HAND SMP352
PLCM11
DP
User :t ayvaz
MOISTURE U351A
T351A
MOISTURE U352A
PLCM11
MS
%DO
%DO
ON HTU351
OPEN NWS351
PLCM11
%DI
TEMP T352A
PLCM11
PLCM11
AUTO
NWS351
SMP351
PLCM11
PLCM12
DI
PLCM12
DP
FVNR
MS SMP352
PLCM11
DP
AUTO
DI
DP
DI
DP
SMP351
PLCM12
DP
DI
DP TEMP
DI
%AI
DP
DI
LEVEL
PLCM11
L351C
DI
INST
LEVEL
PLCM11
L353
PLCM11
%AI LEVEL L352
FVNR
PLCM12
DP
INST
AUTO SMP352
PLCM12
DI
PLCM12
DP LEVEL L352A
DI
PLCM12
PRO
PRO
POWER
OL
NC
OL
SMP351
R1
CPT
CPT
HTU351
SMP351
SMP352
120VAC
CB HTU351
MS SMP351
1103LP1
NC
SMP352
FVNR
MCC1101
R1
MS
SMP351
SMP352
FVNR
MCC1102
R1 SMP352
FIELD WET WELL HTU351
ASB SCUM
HEAT TRACE
NWS351
NON-POT WATER
UNIT
SOLENOID
ML_313
ML_313
ASB
OIL HOA
SS
HOA SMP351
NWS351
SS
L351C
SWITCH
SMP351
SMP351
HYDROSTATIC
SCUM
U351A
MOISTURE
LEVEL
L353
SMP351
PUMP ML_313
ASB
HYDROSTATIC L352
LEVEL
HOA
0-15 FT
0-15 FT
ML_313
ML_313
SS
SMP352
SMP352
SCUM
PUMP
OIL U352A
MOISTURE
SMP352
L352A
SWITCH
SMP352
ML_313
1
1 T351A
TEMP
T352A
SMP351
TEMP
SMP352
S NON-POT WATER LOOP
1 1/2" NPW SCUM WETWELL CONTINUED ON DRAWING PI-ABM-4
3" S
3" S
6" S
TO MH-47 REFER TO PI-IVM-2
VALVE VAULT
14" PD
TO MH-47 REFER TO PI-IVM-2
NL131 TYP
(TYP OF 2)
RECORD DRAWING
$$$$PLOT_I NFO$$$$
THESE RECORD DRAWINGS HAVE BEEN PREPARED BASED IN PART ON INFORMATION PROVIDED BY OTHERS THIS DRAWING WAS PREPARED ONLY FOR THE PROJECT AND SITE SPECIFICALLY IDENTIFIED HEREON AND IS NOT TO BE USED ELSEWHERE SMP351
SMP352
ASB SCUM PUMP
ASB SCUM PUMP
5HP, 480VAC, 3PH
5HP, 480VAC, 3PH
Date
JOB NO: 1700665
By
DESIGNED BY:
MKR
DRAWN BY:
SMW
CHECKED BY:
APPROVED BY:
ALM
VERIFY SCALE 0
APPROVED BY:
LICENSE NO.
DATE
SUBMITTED BY:
LICENSE NO.
DATE
1/2
CITY OF FORT COLLINS UTILITIES MWRF IMPROVEMENTS
Denver 1
Colorado
PROCESS & INSTRUMENTATION DIAGRAM IF THIS BAR DOES
REV. DATE
CAH BY
RECORD DRAWING DESCRIPTION
ACTIVATED SLUDGE BASIN SCUM PUMP STATION
NOT MEASURE 1" ADJUST SCALES ACCORDINGLY
SCALE:
REV.
DRAWING NO.:
N/A
PI-WCM-1
SHEET
OF
This page left intentionally blank
EXAMPLE DRAWINGS MECHANICAL – ROTARY LOBE PUMP Mechanical Plan Mechanical Section
This page left intentionally blank
Pl ot Date: 16-SEP-2011 08:22
3’-0"
8’-10"
8" WAS (26) SECONDARY CLARIFIER NO. 4
SECONDARY CLARIFIER NO. 3 6" WAS (26)
03-FCL-210
LANDING
03-FCL-200
FLOW METER 12" RAS (26)
24" RAS (26)
03-FE-276
UP
UP
12" RAS (26) 4" S (16) 3’-4" 6" WAS (26)
D
BEND, TYP
5’ -0"
3’ -0"
User: tayvaz
3M-16
TYP WAS PUMP
2" PW (16)
INSTALLATION
TO 18" RAS
6" WAS (26)
HEADER TYP TYP SCUM PUMP 1" H (32)
INSTALLATION 2" PD (16) 2’-1"
4" CT" (16)
6’-6" SCUM PUMP
03-P-273
8 " PD (26)
03-P-272
03-P-270
03-P-271
03-P-201
4" PD (27)
36" DIAMETER
SCUM PUMP
SCUM HOPPER,
03-P-211 6’-6"
3’-4"
3’-2"
6’-6"
M-826
2" PW (16)
2" PD (16)
48" SE (11)
14’ -7
" 03-P-254
36" SE (11) M-917
SEAL WATER
S
RAS PUMP #8
10’ -0"
7’ -0"
3" HD
G
S G
10’ -0"
" 14’ -7
3M-16
3" HD
7’ -0"
TYP OF 4
Pl otScal e: 8:1
2’-1"
S
C PUMP STATI ON L
WAS PUMPS,
03-P-255
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
18’ -6"
RAS PUMP #7
SUCTION
12" RAS (26)
C 6’-6"
SUPPLY, TYP
PUMP
48" SE (11)
TYP SEAL WATER
PANEL
2" PD (16) 3" HD
03-P-256
C PUMP STATION L
RAS PUMP
WATER S
PANEL
4" PD (27)
B "
3M-15
14’ -7
SEAL
G
TYP RAS PUMP
G
M-917
3" HD
14’ -5"
03-P-257
G
S
FUTURE
10’ -0"
FLANGE
48"x48" TEE
S
12" BLIND
7’ -0"
3" HD
2" UW (16)
7’ -0"
G
S
16" PD (26) 03-P-253
INSTALLATION
48"x36" REDUCER
03-P-252
M-304 3" HD, TYP FUTURE SCUM HOPPER 36" SE (11)
Col orTabl e: bw.ctb
AND SCUM PUMP
6’-1"
20’-4"
20’-4"
6’-1"
2" UW (16)
03-P-241 2" VTR
2" VTR
1" H (32) 4" CT" (16)
3" FLOOR M-304 DRAIN,
(FUTURE)
03-P-221
RAS/WAS PUMP STATION
6’-6"
TYP M-803
Model : Defaul t
2’-1"
SCUM PUMP
8" PD (26)
12" PLUG VALVE, TYP OF 4
M-803
FUTURE
12"x8" WYE, TYP OF 4
SECONDARY CLARIFIER NO. 6
EFFLUENT DROP BOX, TYP
03-FCL-240 Rotary Lobe Pum p-Pl an.dgn
8" PLUG VALVE, TYP OF 4
ACCESS ROAD 2" PW (16)
12" RAS (26)
12" RAS (26) SECONDARY CLARIFIER NO. 5
A
03-FCL-220
3M-15 SCALE
Fi l e: 007
SUBMITTED BY
WARNING 0
1
DESIGNED
DESIGN
DRAWN
DRAWN
(PROJECT MANAGER’S NAME) " = 1’-0"
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
CITY OF CAPE CORAL LICENSE NO.
DATE
SOUTHWEST WATER RECLAMATION FACILITY EXPANSION (WW-2)
CHECKED
CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
EXAMPLE - ROATARY LOBE PUMP MECHANICAL
1
PLAN Job No.
Pl ot Date: 16-SEP-2011 08:22
(TYP)
4" S (16)
M-106
4" S (16)
S
S
CL EL 20.67 6" S (16)
4" CK
24" RAS (26)
VALVE 4" S (16)
6" WAS (26)
6"x8"
DISCHARGE
RED
CL EL 16.50 User: tayvaz
SUCTION CL EL 15.67
CL EL 15.58
36" DIA
4" S (16)
6" WAS (26)
6" S (16)
SCUM HOPPER TYP
6" RUPTURE CL EL 14.17 S
DISC, TYP CL EL 12.83
G
G
S
CL EL 11.87
CL PUMP
CL EL 10.96
EL 11.50 FF EL 10.00 03-P-211
PIPE SUPPORT
03-P-270 2" BALL VALVE, TYP
M-150
03-P-271
03-P-272
03-P-273
03-P-201
36" SE (11)
2" PD (16) M-140
M-108
WITH U-BOLT M-304
3" HD
1
4" PD (27)
8" RAS (26) 8" RAS (26)
TO MH #21 12" RAS (26)
12" RAS (26)
SECTION
C
Pl otScal e: 8:1
3M-11
Desi gnScri pt: MW H_I pl ot_Pentabl e_v89.pen
3M-12
24" RAS (26) 6" WAS (26)
4" S (16)
DISCHARGE
6" WAS (26) SUCTION
6" RUPTURE
Col orTabl e: bw.ctb
DISC, TYP
03-P-273
03-P-271
03-P-270
CL EL 6.67 CL EL 4.50
Model : Defaul t
4" S (16)
Rotary Lobe Pum p-Sect.dgn
(TYP) M-108 WITH U-BOLT
SECTION
D 3M-11 3M-12
SCALE
Fi l e: 007
SUBMITTED BY
WARNING 0
1
DESIGNED
DESIGN
DRAWN
DRAWN
(PROJECT MANAGER’S NAME) " = 1’-0"
REV
DATE
BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
SHEET
CITY OF CAPE CORAL LICENSE NO.
DATE
SOUTHWEST WATER RECLAMATION FACILITY EXPANSION (WW-2)
CHECKED
CHECKED
(COMPANY OFFICER’S NAME)
LICENSE NO.
DATE
EXAMPLE - ROTARY LOBE PUMP MECAHNICAL
2
SECTION Job No.
EXAMPLE DRAWINGS MECHANICAL – DEEP WELL PUMP STATION
Mechanical Plan – Submersible Pump Mechanical Section – Submersible Pump Mechanical Plan – Vertical Turbine Pump Mechanical Section – Vertical Turbine Pump
This page left intentionally blank
Pl otDat e: 01SEP2011 15: 08 User :t ayvaz
7450
STANDARD TEMPLATE
*
600
TO SURGE TANK
SUBMERSIBLE TURBINE WELL PUMP
M108
PIPE SUPPORT, (TYP)
FLOWMETER
’A’ mm W (DI) TO DISTRIBUTION OR BALANCE TANK, SEE TABLE FOR PIPE SIZE
1020 (MIN)
600
1200
610 (MIN)
A STWM-2
GATE VALVE, (TYP)
AIR VACUUM AND AIR RELEASE VALVE
’B’ mm BO (DI) BLOWOFF
CHECK VALVE
M156
SLEEVE TYPE COUPLING WITH
Fi l e: 009 Deep W el lSub Pl an. dgn
M odel : Layout 1
Col or Tabl e: bw. ct b
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
Pl ot Scal e: 54: 1
HARNESS, (TYP)
WARNING 0
1
2
SHEET 3
IF THIS BAR DOES 0
06/30/10
MWH
ISSUED FOR TENDER PACKAGE
REV
DATE
BY
DESCRIPTION
DESIGNED
DRAWN
NOT MEASURE 3 cm THEN DRAWING IS NOT TO SCALE
CHECKED
J ADIDJAJA
R SASAKI
PALESTINIAN WATER AUTHORITY PROGRAM FUNDED BY THE U.S. AGENCY FOR INTERNATIONAL DEVELOPMENT (USAID) INFRASTRUCTURE NEEDS PROGRAM
SUBMERSIBLE TURBINE WELL MECHANICAL
STWM-1
DWG:
WB-GM-STW-01
DATE:
JULY, 2010
SUBMERSIBLE TURBINE WELL PUMP - PLAN SCALE:
1:25
Pl otDat e: 01SEP2011 15: 08 User :t ayvaz
AIR VACUUM AND AIR RELEASE VALVE
GATE VALVE, (TYP)
TO BLOWOFF FLOWMETER
’A’ mm W (DI)
450
TO DISTRIBUTION OR BALANCE TANK, SEE TABLE FOR PIPE SIZE
Pl ot Scal e: 54: 1
M108
PIPE SUPPORT, (TYP)
CENTRALIZER, (TYP)
1500 M156
SLEEVE TYPE COUPLING WITH
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
HARNESS, (TYP)
DATA LOGGER
SECTION 1:25
A
SUBMERSIBLE VERTICAL TURBINE PUMP
STWM-1
Fi l e: 009 Deep W el lSub Sect i on. dgn
M odel : Layout 1
Col or Tabl e: bw. ct b
SEE WELL DETAIL, XX/XX
WARNING 0
1
2
SHEET 3
IF THIS BAR DOES 0
06/30/10
MWH
ISSUED FOR TENDER PACKAGE
REV
DATE
BY
DESCRIPTION
DESIGNED
DRAWN
NOT MEASURE 3 cm THEN DRAWING IS NOT TO SCALE
CHECKED
J ADIDJAJA
R SASAKI
PALESTINIAN WATER AUTHORITY PROGRAM FUNDED BY THE U.S. AGENCY FOR INTERNATIONAL DEVELOPMENT (USAID) INFRASTRUCTURE NEEDS PROGRAM
SUBMERSIBLE TURBINE WELL MECHANICAL
STWM-2
DWG:
WB-GM-STW-02
DATE:
JULY, 2010
SUBMERSIBLE TURBINE PUMP WELL - SECTION SCALE:
1:25
Pl otDat e: 01SEP2011 15: 08 User :t ayvaz
7450
STANDARD TEMPLATE
*
600
TO SURGE TANK
LINESHAFT TURBINE WELL PUMP
FLOWMETER
GATE VALVE, (TYP)
’A’ mm W (DI) TO DISTRIBUTION OR BALANCE TANK, SEE TABLE FOR PIPE SIZE
1020 (MIN)
600
1200
610 (MIN)
A VTWM-2
M108
PIPE SUPPORT, (TYP)
AIR VACUUM AND AIR RELEASE VALVE
’B’ mm BO (DI) TO BLOWOFF
CHECK VALVE
M156
SLEEVE TYPE COUPLING WITH
Fi l e: 009 Deep W el lVTP Pl an. dgn
M odel : Layout 1
Col or Tabl e: bw. ct b
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
Pl ot Scal e: 54: 1
HARNESS, (TYP)
WARNING 0
1
2
SHEET 3
IF THIS BAR DOES 0
06/30/10
MWH
ISSUED FOR TENDER PACKAGE
REV
DATE
BY
DESCRIPTION
DESIGNED
DRAWN
NOT MEASURE 3 cm THEN DRAWING IS NOT TO SCALE
CHECKED
T AYVAZ
R SASAKI
PALESTINIAN WATER AUTHORITY PROGRAM FUNDED BY THE U.S. AGENCY FOR INTERNATIONAL DEVELOPMENT (USAID) INFRASTRUCTURE NEEDS PROGRAM
VERTICAL TURBINE WELL MECHANICAL
VTWM-1
DWG:
WB-GM-VTW-01
DATE:
JULY, 2010
LINESHAFT TURBINE WELL PUMP - PLAN SCALE:
1:25
Pl otDat e: 01SEP2011 15: 08 User :t ayvaz
AIR VACUUM AND AIR RELEASE VALVE
GATE VALVE, (TYP)
TO BLOWOFF FLOWMETER
’A’ mm W (DI)
450
TO DISTRIBUTION OR BALANCE TANK, SEE TABLE FOR PIPE SIZE
Pl ot Scal e: 54: 1
M108
PIPE SUPPORT, (TYP)
1500 M156
SLEEVE TYPE COUPLING WITH
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
HARNESS, (TYP)
CENTRALIZER, (TYP) DATA LOGGER
SECTION
A
LINESHAFT VERTICAL TURBINE PUMP
VTWM-1
Fi l e: 009 Deep W el lVTP Sec. dgn
M odel : Layout 1
Col or Tabl e: bw. ct b
SEE WELL DETAIL, XX/XX
WARNING 0
1
2
SHEET 3
IF THIS BAR DOES 0
06/30/10
MWH
ISSUED FOR TENDER PACKAGE
REV
DATE
BY
DESCRIPTION
DESIGNED
DRAWN
NOT MEASURE 3 cm THEN DRAWING IS NOT TO SCALE
CHECKED
J ADIDJAJA
R SASAKI
PALESTINIAN WATER AUTHORITY PROGRAM FUNDED BY THE U.S. AGENCY FOR INTERNATIONAL DEVELOPMENT (USAID) INFRASTRUCTURE NEEDS PROGRAM
VERTICAL TURBINE WELL MECHANICAL
VTWM-2
DWG:
WB-GM-VTW-02
DATE:
JULY, 2010
LINESHAFT TURBINE WELL SITE - SECTION SCALE:
1:25
EXAMPLE DRAWINGS MECHANICAL – ADDITIONAL DETAILS Meter Run Plan and Section
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B -
Pl otDat e: 16SEP2011 08: 27
EDGE OF ROAD
44’-8"
1
9’-3 2"
8’-6"
FE 366
34’-6"
10’-2"
36" TW (11) C L 09-ME-377
2’-5 1/2 "
C L 2’-0"
2" DRAIN VALVE BELOW 4’-6"
BACKFLOW PREVENTER
1
8’-7 4"
20’-0"
8’ 3"
User :t ayvaz
4’ 10"
36" TW (11)
6’-4"
MAG METER 2’-0"
09-V-376
09-V-365
09-V-367
FE-363
A
36"x36" TEE (TYP)
09-FIT-375
9’-7"
7’ 9"
8" PW (11)
09-V-362
09-V-364 15’-0"
9’-0"
30’ 8"
METER RUN - PLAN
42" TW (11)
ENGINEER TO CONFIRM MINIMUM UPSTREAM AND DOWNSTREAM PIPE RUNS WITH METER MANUFACTURER. MINIMUM DISTANCES ARE REQUIRED FOR ACCURACY.
CONCRETE ENCASED SEE STRUCTURAL MATCH LINE SEE DWG 09M-1
X
Pl ot Scal e: 2: 1
X
09-ARV-361 09-PIT-368A
M-804
Desi gnScr i pt : M W H_I pl ot _Pent abl e_v89. pen
36"x36" TEE (TYP) 09-V-362 MAG METER
M-902
09-FE-363
11’ 0"
3’ 10"
8’ 6"
5’ 0"
36" TW (11)
36" TW (11) 09-V-374 FF 15.0’
3’ 6"
6’ 3"
FG 14.5’
M odel : Layout Col or Tabl e: bw. ct b Fi l e: Det ai l s M et erRun. dgn
09-PIT-368B
09-V-365
M-804
M-110
2" DRAIN LINES 1 2"
SA-5(30)
36" TW (11) 09-V-364
8" PW (11) 8" PW (11) CONCRETE PIER PIPE SUPPORT (TYP)
36" TW (11) 42" TW (11)
36" TW (11)
M-110
M-150
SECTION
SECTION
B -
SCALE
WARNING 0
1 2
PROJECT 1
DESIGNED
DESIGN
REV
07/01/09 DATE
GUIDE BY
DESCRIPTION
IF THIS BAR DOES NOT MEASURE 1" THEN DRAWING IS NOT TO SCALE
DRAWN
DRAWN
CHECKED
CHECKED
SHEET
* *
SCALE
A
A -
HIGH SERVICE PUMP STATION
*
MECHANICAL
*
METER RUN PLAN AND SECTIONS
9M-2 Job No.
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