WAGNER INSTRUMENTATION 2000 INC. 8020 El Rio Houston, Texas 77054 Phone: 713-741-9470 Fax: 713-741-9473
E-Mail:
[email protected] World Wide Custom Instrumentation
Committed to our Customers since 1980 Instruction Manual Hydraulic Load Cell Systems
IMPORTANT SAFETY NOTICE
Proper service and repair is important to the safe, reliable operation of all Wagner Instrumentation equipment. The service procedures recommended by Wagner Instrumentation and described in the service manuals are recommended methods of performing service operations. Some of these service operations require the use of tools specially designed for the purpose. The special tools should be used when and as recommended. The importance to note that some warnings against the use of specific service methods that can damage the equipment or render is unsafe are stated in the manuals. It is also important to understand these warnings are not exclusive, Wagner Instrumentation could not possible know, evaluate and advise the service people of all conceivable ways in which service might be done or of the possible hazardous consequences of each way. Accordingly anyone who uses service procedures, or tools, which are not recommended by Wagner Instrumentation, must first satisfy himself thoroughly that neither his safety nor equipment safety will be jeopardized by the method selected.
CONTENTS
Section 1 Introduction and Description 1.1 Introduction 1.3 Description
Page No. 2 2 2
2 2.3 2.4 2.5 2.6 2.7 2.9
Installation and Operation Pre-Installation Loadcell Installation Indicator Installation Hydraulic Hose Installation Post Installation Checkout System Operation
3 3 4 4 4 4 4
3
System Accuracy
5
4 4.1 4.3 4.5 4.6
Repair Repair Component Repair Loadcell Gap Charging and Bleeding System
5 5 5 5 6
4.1
Nominal Cell Gap
6
1.1 1.2 1.3 1.4
1.5 1.6 1.7
1.8 1.9
1.10 1.11
1.12 1.13 1.14 1.15 1.16 1.17
Introduction This manual provides Installation and Operation maintenance instructions for Compression Loadcell Systems. Description The Loadcell Systems are hydraulically operated, pre-loaded and are fully assembled prior to shipment. They are available in several sizes up to 150,000 Single Point load. Gauges are available in 6”, 8 ½, 12” and 16” to meet your specifications. Theses systems are designed to operate in the temperature range of –50^F to 150^ F. The Loadcell System consists of three basic components: The Indicator, Hydraulic Hose assemblies and Hydraulic Loadcell. System Components The loadcell system consists of the following components and attached hardware as needed. A. Indicator B. Sensator Loadcells C. Hydraulic Hoses D. Disconnects Indicator The indicator provides a dial faceplate, calibrated in pounds, tons or kilograms. As specified, the indicator has a damper to smooth pointer sensitivity and to adjust the pointers response to the Operators’ preference. The indicator has a dial adjust to zero out the tank weight. Loadcell The loadcell transmits a no-lag linear load indication signal to the indicator be transforming the applied load to the hydraulic signal. This is accomplished by a sensator diaphragm-sensing element held in place by the loadcell housing. Hose A ¼” diameter hose is of double wire braid construction and rubber covered. The connection is of ¼” NPT male. Disconnects A disconnect set is provided to provide in-line separation of the indicator from the hose and loadcell. Tubing Tubing may be used if long runs, from the cell to the indicator are needed.
1.18 1.19
2.1 2.2
2.3 2.4
Attached and Support Hardware The system is furnished with all necessary attaching support hardware to facilitate installation and maintenance. A. Check Valve- Mounted at the indicator for loading B. Hand Pump for pumping hydraulic fluid to load C. Hydraulic fluid supplied for field loading Pre-Installation The pre-installation procedure consists primarily of insuring that the loadcell system is the correct system to be installed. Items to be confirmed: A. Indicator dial is calibrated in the units of measurement compatible with what will be measured. Ex: Pounds, Tons, Kilograms or SI Metric. B. Check Disconnect o-rings for damage. C. Loadcell capacity suitable for load to be weighed. D. Determine that the Loadcell and hydraulic hose is located in a position to move freely, considering any obstructions that may interfere with the load to be measured. Also, determine that hydraulic hose is of sufficient length for routing from the indicator to the Loadcell. E. Verify condition of hose, disconnects and fittings to ensure that they will not leak fluid when mated. System Installation Loadcell Installation The Loadcell can be mounted in any position, dependent upon the application. The load plates of the cell may be tilted a maximum on 2^ from the parallel position to facilitate installation without causing a measurement error. Misalignment (lateral displacement) of the load plates is tolerable; however is misalignment exceeds .06”, it will produce a slight error in indication and increased wear to the diaphragm will result. CAUTION
The Loadcells are incapable of supporting torsion loads of any significance. Torsion loads will case the diaphragm to rotate over the pressure plate, resulting in early failure. In applications where twisting in encountered, a swiveling device must be used to relieve the Loadcell from torsion loads.
2.5
2.6
Indicator Installation Select a location for the indicator that will provide convenient visual access to the operator. A. Drill four mounting holes for bracket. B. Install Indicator. Hydraulic hose Installation A. Route hose so that it will not be crushed, cut or otherwise damaged. B. Tie hose to structures where permitted. CAUTION Allow sufficient slack in the hose to avoid pulling hose taut. Excess tension could cause fitting or connector failure.
C.
2.7 2.8
2.9 2.10 2.11
Connect disconnects in accordance with the following procedures. 1. Carefully align male and female coupling. 2. Push two halves together firmly. 3. Thread nut onto male half of coupling tight. NOTE O-ring may be damaged if not inserted straight. If so, see paragraph 4-4 Post installation check out After system installation, check to insure that it is operating properly. A. Check Loadcell for proper gap. (See table 4-1) B. Check the damper. It should be closed off and backed off two turns. If pointers are too sensitive, turn clockwise. If pointers are slow to move, turn damper counter clockwise. System operation The load indicating system is automatic, but two adjustments of the Loadcell system indicator are necessary prior to initial use of the system. Load pointer zero (tare) adjustment A. Apply load to the system B. Remove load C. Adjust tare, then adjust knob until indicator pointer reads zero with all tare loads acting on loadcells.
2.12
3.1 3.2
4.1 4.2
4.3 4.4
4.5 4.6
Pointer damping adjustment The adjustment is designed to adjust pointer sensitivity to the operator’s preference. However, the adjustment can affect indicator response if too much dampening is applied. The following procedure is recommended to achieve desired sensitivity. The dampers are located on the front panel of indicator. A. Fully engage all dampers by pushing stem into thread engagement and turn stems clockwise to close. B. Open all dampers by turning stems counterclockwise (2) complete revolutions. C. If pointer is too sensitive, turn all damper stems clockwise ½ revolution. D. If pointer is sluggish, turn all damper stems counter clockwise ½ revolution. E. Re-check sensitivity and repeat appropriate steps until desired sensitivity is reached. System Accuracy System accuracy is such that the indicated load should not differ from actual load more the +/-0.5 of one percent of full scale. System Repair System repair is limited to removing a faulty component and replacing it with one in serviceable condition. This section of the manual explains repairs that may be readily preformed in the field and does not include detailed disassembly/assembly procedures of the indicator and Loadcell. Field repairs consist of charging or bleeding the hydraulic system, removing and replacing the indictor, Loadcell and/or hydraulic hose. Component Repair Disconnect O-ring replacement. If the O-ring in the female half of the disconnect becomes damaged during mating or other cause, it must be replaced to preserve the integrity of the system. A. Remove damaged O-ring for the female half. B. Clean O-ring groove. C. Lubricate and install new O-ring (WR107-011). D. Disconnect is ready to be returned to service. Loadcell Gap Refer to figure 4.1. The Loadcell gap is the distance measured between the load plate and the Loadcell retaining ring. The nominal gap is the proper gap for a Loadcell, as specified in table 4.1. The nominal gap may vary up to - + 1/8” to achieve accuracy.
4.7 4.8 4.9
Charging and Bleeding System Hydraulic Fluid Application The system must maintain the proper load at all times to achieve proper system accuracy. A quick check for adequate fluid in the system is the gap between Loadcell, load late and retainer ring. Hydraulic fluid addition is as follows: A. Remove all weight from Loadcell B. Insure that hose is free of twists and sharp bends C. Remove cap from check valve D. Close dampers E. Attach hand pump to check valve F. Fill hand pump reservoir with hydraulic fluid G. Operate hand pump plunger slowly H. Loosen Loadcell ¼” plug I. Hold cell, so plug bleed point is at the top J. Pump through system and bleed until no air bubbles K. Replace plug and tighten L. Pump enough fluid into the system to slightly overcharge the Loadcell M. After loading all loadcells, bleed to proper gap
Nominal Cell Gap Table 4-1
Effective Area Sq Inch. 6.44 8.00 12.00 16.10 25.00 36.77 50.00
Nominal Gap 7/16 3/8 7/16 7.16 ½ 5/8 ¾
Figure 4-2
