Centrifugal Pump Piping

TRAINING MANUAL- PIPING

Uhde India Limited

PIPING STUDY PUMP (CENTRIFUGAL) PIPING

DOC No. : 29040-PI-UPS-1005 Rev.

: R0

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CONTENTS Page 0.0

Cover Sheet

1

List of drawings

2

1.0

General

3

2.0

Location

3

3.0

Steps to do Pump Piping

4

4.0

Pump Piping

4-5

5.0

Suction Basin of Pump

6

Applicable Revision: Prepared:

Checked:

Approved:

Date: First Edition: R0 Prepared: AKB

Date:

Date:

Checked: TNG

Approved: RUD

Date: File Name:

Date: Server:

Date: VKO: KUMUS 209

PUNE: KUMUS 207


Uhde India Limited


SR.NO. DWG.NO.


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DESCRIPTION

1

CPP1

CENTRIFUGAL PUMP

2

CPP2

TYPICAL CENTRIFUGAL PUMP

3

CPP3

FLUID FLOW IN A CENTRIFUGAL PUMP

4

CPP4

TYPICAL PUMP LOCATION - PLAN

5

CPP5

TYPICAL ACCESS FOR MAINTENANCE

6

CPP6

TYPICAL PUMP LOCATIONS - ELEVATION

7

CPP7

AIR POCKETS IN SUCTION PIPING

8

CPP8

TYPICAL PUMP SUCTION & DISCHARGE PIPING

9

CPP9

ELBOW AT PUMP SUCTION

10

CPP10

TYPICAL AUXILLIARY PUMP PIPING

11

CPP11

MAINTENANCE AND OPERATIONAL ACCESS REQUIREMENTS

12

CPP12

TYPICAL SUCTION / DISCHARGE PIPING, PLAN & ELEVATION

13

CPP13

TYPICAL SUCTION / DISCHARGE PIPING, FRONT VIEW

14

CPP14

MULTIPLE PUMP INSTALLATIONS (VERTICAL PUMP)

15

CPP15

SUMP DIMENSIONS, PLAN VIEW, WET PIT TYPE PUMPS

16

CPP16

TYPICAL SUMP WITH PUMP


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GENERAL The design of a piping system can have an important effect on the successful operation of a centrifugal pump. Such items as sump design, suction piping design, suction and discharge pipe size and pipe supports must all be carefully considered. A typical horizontal centrifugal pump installation is illustrated in Fig.CPP1, CPP2, CPP3. Selection of the discharge pipe size is primarily a matter of economics. The cost of various pipe sizes must be compared to the pump size and power cost required to overcome the resulting friction head.

1.1

The suction piping size and design is far more important. Many centrifugal pump troubles are caused by poor suction conditions.

1.2

The suction pipe should never be smaller than the suction nozzle of the pump and in most cases it should be at least one size larger. Suction pipes should be as short and as straight as possible. Suction pipe velocities should be in the 1.0 - 1.5 metre per second range, unless suction conditions are unusually good. Higher velocities will increase the friction loss and can result in trouble some air and vapour separation. This is further complicated when elbows or tees are located adjacent to the pump suction nozzle. In that case uneven flow patterns or vapour separation keeps the liquid from evenly filling the impeller. This upsets hydraulic balance leading to noise, vibration, possible cavitation and excessive shaft deflection. Cavitation, erosion damage, shaft breakage or permature bearing failure etc. may result.

1.3

On pump installations involving suction lift, air pockets in the suction line can be a source of trouble. The suction pipe should be exactly horizontal or with a uniform slope upward from the sump to the pump as illustrated in Fig.CPP7. There should be no high spots where air can collect and cause the pump to lose its prime. Eccentric rather than concentric reducers with flat side top should always be used.

1.4

If an elbow is required at the suction of a double suction pump, it should be in a vertical position if at all possible. Where it is necessary for some reason to use a horizontal elbow, it should be a long radius elbow and there should be a minimum of five diameters of straight pipe between elbow and the pump suction as illustrated in Fig.CPP9.

2.0

LOCATION

2.1

Common location of pumps in chemical and petrochemical plant is under the piperack at grade. Pumps are to be placed close to and below the vessels from which they take their suction in order to have net-positive suction head (NPSH) required by the pump.

2.2

Any reduction in suction line size required at pumps should be made with eccentric reducers, with flat side up to avoid accumulation of vapour pocket. Changes in direction of suction lines should be at least 600mm away from the pump suction.

2.3

Pumps should be arranged in line with drivers facing the access gangway. Clearances and piping should provide free access to one side of the driver and pump. There must be good access to gland / seal and coupling where most of the maintenance and adjustments are done.


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With normal piperack column spacing of 6m, it is generally found that only two pumps of average size can be arranged between the columns, with a preferred clearance of 1m between the pumps. The clearance between any structure / steel work and the pump discharge line shall be 0.75m minimum. For small pumps upto 18 KW, clearance between pumps should be 0.9m minimum. A space of 2 - 2.5 m should be provided for working aisle. A typical arrangement of pumps is illustrated in Fig.CPP4, CPP5, CPP6.

2.5

Means of lifting should be provided for pumps or motor weighing more than 25Kg.

3.0

"STEPS TO DO PUMP PIPING" Step 1 : Collect the P&ID and the pump data sheet. Step 2 : Study the pump data sheet and collect the similar (capacity / head) pump dimensions / nozzle position. Step 3 : Analyse the location and the space provided in the unit plot plan w.r.t. suction and discharge line routing. Step 4 : Review the maintenance / operation space around and lifting facility. Step 5 :

Locate the control station, Electrical push button station, Electrical-trench, process fluid drain, flushing / cooling connection as required for the pump model.

Step 6 : Check elevations of all valve handwheels on suction as well as discharge line and provide common platform for valve operation, if required. Step 7 :

Make Iso sketch for suction and discharge line with all the items as per P&ID and discuss with process engineer for any change.

Step 8 :

Finalise supports of the line and issue for stress analysis, if required.

Step 9 :

Get the stress analysis report for Nozzle loads. Compare the allowable loads with the actual load for any change & finalisation.

Step 10 : Finalise location of pump / drain or trench / Electrical cable route and issue civil information to civil for foundation design. Step 11 : Keep necessary insert plate on the foundation block for support of push button switch, small lines for flushing / cooling manifold.

4.0

PUMP PIPING :

4.1

HORIZONTAL CENTRIFUGAL PUMP : A typical horizontal centrifugal pump suction and discharge piping arrangements is illustrated in Fig.CPP7.

4.2

Pump suction piping shall be as short as possible and shall be arranged so that vapour pockets are avoided.

4.3

Reducers immediately connected to the pump suction shall be eccentric type flat side up to avoid accummulation of gas pocket.


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For end suction pumps, elbows shall not be directly connected to the suction flange. A straight piece 3 times the line size shall have to be provided at the suction nozzle. This is illustrated in Fig.CPP8. The effect of elbow directly on suction is illustrated in Fig.CPP9.

4.5

For top suction, pump elbow shall not be directly connected to suction flange. A straight piece of minimum 5 times the nozzle size shall have to be provided at the suction nozzle.

4.6

T-type strainers are to be used for permanent as well as temporary to avoid disassembly of suction piping for strainer cleaning.

4.7

Piping shall be so arranged that forces and moments imposed on the pump nozzles do not exceed the allowable values specified by the vendor.

4.8

When a suction vessel operates under vacuum the vent connection of the pump has to be permanently connected to vapour space of the suction vessel to allow possible filling of the pump with liquid before it is started.

4.9

For pumps handling hot fluid, the first factor concerns the support of pump piping which often includes large expansion loops for flexibility. When the pumps are located below the piperack (to reduce possibility of hydrogen leakage over motor), support becomes easy otherwise the designer should consult stress engineer for best location of stops and hanger. With the optimum layout and support, it is to be ensured that the loadings on the pump nozzles are not exceeded beyond the allowable limits.

4.10

Piping configuration for a group of pumps of similar size shall follow identical pattern and the stress analysis of one pump piping should be applicable to the other pumps.

4.11

Auxilliary Pump Piping Arrangements : The auxilliary piping are usually cooling water to mechanical seals, bearings, stuffing boxes, gland quench and lantern rring flush. When pump fluid is used, a line is attached to the vent connection on the pump case. The circulated seal fluid has to be sent back to pump stream or referred through the seal to pump internal clearances. In viscous or high temperature hydrocarbon liquids, the seal fluid medium circulates from external source through connections on the pump seal. Various auxilliary piping plan is recommended in API 610 for proper selection according to design requirements.

4.12

Pump vendors usually supply the auxilliary piping and the neat arrangements of these piping and its support are to be ensured by the designer while reviewing the vendor document. Fig.CPP10 illustrates one typical auxilliary pipig arrangement on the pump base plate.

4.13

A typical arrangement for piping and valves operation is illustrated in Fig.CPP11 with maintenance and operation access.

4.14

A typical suction and discharge piping arrangement with common platform for operation of valves connected to two adjacent pumps is illustrated in Fig.CPP12 and CPP13.


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5.0

SUCTION BASIN OF PUMP

5.1

The basin for the intake of centrifugal pump shall be designed and sized properly for smooth function of the pump. The recommendations of hydraulic institute is illustrated in Fig.CPP14.

5.2

The flow of fluid to the suction bell should be even, smooth and stream lined without any vortices.

5.3

A typical sump with the components and relative dimensions of clearance and submergence is illustrated in Fig.CPP15.

5.4

For multiple pump installations with high capacity pumps, the analysis of a proposed intake design are often made by use of a scale model of the intake basin with all parts such as baffles, screens, gates, separating walls etc. The large basin is required to ensure low inlet velocity (approx. 2 ft. per sec.) and to eliminate vortexing at the bell mouth.

5.5

A typical sump pit with pump is illustrated in Fig CPP16. This sump is the collection pit of waste material coming thru a pipeline. A screen at the mouth of the pump avoids choking / fouling of the pump during operation. The discharge of the pump may go to a slope tank / pond / waste-removal tanker.

TRAINING MANUAL - PIPING

DOC NO. : 29040-PI-UPS-1005

PIPING STUDY PUMP (CENTRIFUGAL)

Uhde India Limited

Rev.

: R0

Page

: 1 OF 1 DWG. NO. : CPP1

CENTRIFUGAL PUMP DISCHARGE (LIQUID OUTLET) CASING VENT

DRIVE ELECTRIC MOTOR

IMPELLER COUPLING

SUCTION (LIQUID INLET)

CASING

CASING DRAIN

COUPLING GUARD

STUFFING BOX DRAIN BASE PLATE DRAIN

BASE PLATE

ELECTRICAL TERMINAL BOX

COUPLING GUARD

CL DISCHARGE

ELEVATION

BASE PLATE

CL MOTOR

CL PUMP

AUXILLIARY PIPING

PLAN

C L SUCTION

C L BASE PLATE DRAIN


Uhde India Limited


DOC NO. : 29040-PI-UPS-1005 Rev.

: R0

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TYPICAL CENTRIFUGAL PUMP

SEALING AREA

DISCHARGE

THROAT

STUFFING BOX OR SEAL CHAMBER

ROTARY IMPELLER GLAND SHAFT SUCTION EYE

CASING

CENTRIFUGAL PUMP, LIQUID END


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FLUID FLOW IN A CENTRIFUGAL PUMP

DISCHARGE

CASING

IMPELLER VANES

SUCTION EYE

IMPELLER


DOC NO. : 29040-PI-UPS-1005


Uhde India Limited

Rev.

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TYPICAL PUMP LOCATION PLAN

4B

4A

3B

2B

C L OF DISCHARGE NOZZLE

750 750

2A

1B

1A

3A

EQUIPMENT LINE


C L OF PIPERACK COLUMN

PUMP ACCESS WAY

CL OF PIPERACK COLUMN

10C

10B

10A

9C

6B

6A

5B

5A


9B

9A

CL PUMPS (IN LINE)

EQUIPMENT LINE

7A

7B

8A

8B


DOC NO. : 29040-PI-UPS-1005


Uhde India Limited

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TYPICAL ACCESS FOR MAINTENANCE PULSATION DAMPENER

BUNDLE LENGTH

C L

ALLOW ADEQUATE ACCESS TO MOTOR

EXCHANGERS

DROP OUT AREA

CL CHANNEL NOZZLES

6000

CL KO DRUM

TOWER

C L

TOWER

C L

DROP OUT AREA

AIR FIN. COOLER

ENSURE CLEARANCE BETWEEN PLATFORMS

CABLE TRAYS (TYP)

COMPRESSOR HOUSE

CL

C TOWER L

TOWER

CL C L PUMP (TYP)

NO PERMANENT STRUCTURE FOR BUNDLE REMOVAL C L DRUM

L (TYP)

UP ACCESS STAIRWAY

MIN. CLEARANCE OF CL DRUM

ALL OBSTRUCTIONS C L TANK

EQUIPMENT ALIGNED ON COMMON TAN LINE RACK PLATFORM

750 PREFERRED

C L DISCHARGE

FOR BL VALVES

C ROADWAY L

DIMENSIONS ARE IN MM.

6000 MAX.


DOC NO. : 29040-PI-UPS-1005


Uhde India Limited

Rev.

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TYPICAL PUMP LOCATIONS - ELEVATION

AIR COOLER

3000

3000

750 750

5A-5B PUMPS

PUMP ACCESS WAY

(TYP)

IA-IB PUMPS

4A-4B PUMPS

7A-7B PUMPS


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AIR POCKETS IN SUCTION PIPING CHECK VALVE GATE VALVE

ECCENTRIC REDUCER(FST) LONG RADIUS ELBOW

(1a) CORRECT FOOT VALVE (IF USED) STRAINER

CHECK VALVE GATE VALVE ECCENTRIC REDUCER SUCTION PIPE SLOPES UPWARDS FROM SOURCE OF SUPPLY LONG RADIUS ELBOW

SLOPE

(1b) CORRECT FOOT VALVE (IF USED) STRAINER


DOC NO. : 29040-PI-UPS-1005


Uhde India Limited

Rev.

: R0

Page


TYPICAL PUMP SUCTION AND DISCHARGE PIPING

1 4 4 PI 6

PI 6

1 4

4 5

TEMP SUCTION STRAINER

TEMP SUCT. STRAINER

5

1

1

SIDE SUCTION - SIDE DISCHARGE

END SUCTION -TOP DISCHARGE

(BASIC INSTALLATION)

(BASIC INSTALLATION)

1) PIPE SUPPORTS (REST/GUIDE)SHALL BE PROVIDED AT PUMPS TO MINIMIZE WEIGHT AND THERMAL STRESSES BEING APPLIED TO PUMP NOZZLES (NOT TO EXCEED MANUFACTURER'S RECOMMENDATION). LOCATION AND TYPE OF SUPPORT MUST BE APPROVED BY PIPING STRESS ENGINEER. 2) REMOVABLE SPOOL PIECES IN SUCTION PIPING SHALL ALLOW FOR INSTALLATION AND REMOVAL OF TEMPORARY SUCTION STRAINERS. 3) PIPING SHALL BE DESIGNED AND ARRANGED SO THAT CLEARANCE IS PROVIDED FOR REMOVAL OF PUMPS AND / OR DRIVERS. FOR END SUCTION PUMPS THE SUCTION COVER AND PUMP IMPELLER SHALL BE REMOVABLE WHILE THE SUCTION AND DISCHARGE VALVES ARE IN PLACE. 4) VALVE HANDWHEELS SHALL BE ORIENTED WHENEVER PRACTICAL TO BE CONTAINED WITH IN THE PERIMETER OF THE PUMP. 5) PERMANENT SUCTION STRAINERS MAY BE REQUIRED AND SHALL BE SHOWN ON FLOW DIAGRAM. 6) SUITABLE TEMPORARY SUPPORTING FACILITIES AT SUCTON LINES WHEN REMOVING STRAINER. MOTOR

CL PUMP

PLAN VIEW (TOP SUCTION-TOP DISCHARGE)

CL PUMP

MOTOR

PLAN VIEW (END SUCTION-TOP DISCHARGE)

DO NOT LOCATE HANDWHEELS OVER DRIVER OR COUPLING

TRAINING MANUAL - PIPING PIPING STUDY PUMP (CENTRIFUGAL)

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MUST BE MIN. 5D

ECCENTRIC REDUCERWITH TOP HORIZONTAL

D

ELBOW MUST BE VERTICAL WHEN NEXT TO PUMP

(2b) WRONG (2a) PERMISSIBLE

ELBOWS AT PUMP SUCTION

EFFECT OF ELBOW DIRECTLY ON SUCTION


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TYPICAL AUXILLIARY PUMP PIPING

COOLING WATER SUPPLY AND RETURN

CASING VENT VALVE STEM LEAK OFF

CASE DRAIN

STEAM CHEST DRAIN

PEDESTAL COOLING WATER

BEARING COOLING WATER STUFFING BOX DRAIN

END

ELEVATION

COOLING WATER (IN-OUT)

BASE PLATE DRAIN

PLAN


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MAINTENANCE AND OPERATIONAL ACCESS REQUIREMENTS `T' TYPE SUPPORT

PUMP PLOT AREA

ELEVATION

HEIGHT 1500 MAX.

.. FOR OPERATION HEIGHT > 1500 ARRANGE SUITABLE PLATFORM

OPERATION

PLAN


Uhde India Limited

DOC NO. : 29040-PI-UPS-1005


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TYPICAL SUCTION/DISCHARGE PIPING PLAN AND ELEVATION

C PUMP L FO

FO CL PUMP

PLAN

CL PUMP SUCTION EL. VARIES

ELEVATION

B


DOC NO. : 29040-PI-UPS-1005


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1750

CL SUCTION

C SUCTION L

PI

2500

(TYP) 6000 (TYP)

FRONT VIEW

CL DISCHARGE

CL HC DRAIN

CL SUCTION

CL MIN. FLOW

TYPICAL SUCTION/DISCHARGE PIPING - FRONT VIEW


DOC NO. : 29040-PI-UPS-1005


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MULTIPLE PUMP INSTALLATIONS (VERTICAL PUMP) D

ALT.

W

B

Vs=1fps

Ve = 2fps & up if A = less than 4W Ve

w =11/2 to 2D

D

A

A

RECOMMENDED

W = (See Figure 2.26)

NOT RECOMMENDED

B

Add wall thickness to CLdist. round off to give wall ends

For B & C, see Figure CPP15

D

B

RECOMMENDED

NOT RECOMMENDED

D

A

Max. Preferred

= 15° = 10°

A 2

Y

C

RECOMMENDED

NOT RECOMMENDED

Y

D

P

Z

V

Z

V1

D

U

1.0

1.5

Y

2W

3W

V

1

2

2.5

4.0

4.5W 5.5W 4

5

Z = 2.5W or more (W = As per Figure 2.26) or V 1= 0.2 lps or less and Y = Same as chart to left U = Is greater than 40

10.0 9W 6

W = (refer to figure CPP15)

RECOMMENDED

D

NOT RECOMMENDED

F

V = 2 lps

V up to 8 lps

RECOMMENDED

Min. 2F

Z/P

Y

NOT RECOMMENDED UNLESS :

Baffles, grating or strainer should be introduced across inlet channel at beginning of maximum width section

E

NOT RECOMMENDED


DOC NO. : 29040-PI-UPS-1005


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SUMP DIMENSIONS, PLAN VIEW, WET PIT TYPE PUMPS

FLOW

W

SCREEN

TRASH RACK

W

W/2

SINGLE PUMP

W/2

PUMP

W

MULTIPLE SUMP

FLOW

B

Y A OPTIONAL PARTIAL DIVIDERS (INCREASE DIMENSION "W" BY THE DIVIDER THICKNESS) REQUIRED ABOVE 5000 GPM

A B

SCREEN

Y TRASH RACK

S

MIN. WATER LEVEL

C

NOTE: 10° OR LESS PREFERRED WITH 1 FT./SEC VELOCITY MAX. AT SCREEN LOCATION SHOWN. 15° MAX. WITH VELOCITY REDUCED TO 0.5 FT./SEC

D

SUMP DIMENSIONS, ELEVATION VIEW, WET PIT TYPE PUMPS D = (0.744Q) 0.5 RECOMMENDED W = 2D Y > 5D A > 5D C = 0.3D TO 0.5D B = 0.75D

S = D + 0.574Q/D WHERE S - INCHES Q - FLOW (GPM) D - INCHES

1.5


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TYPICAL SUMP WITH PUMP

MOTOR

DISCHARGE NOZZLE

FLOAT DRAIN OR COLLECTION LINE

PUMP WITH STRAINER

Centrifugal Pump Piping

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