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APPENDIX A
GENERAL OPERATION INFORMATION
Abrupt closure of valves in a system can create forces
in excess of normal line pressure. This could result in
damage to the meter and other equipment.
Counters or printers must not be reset when the meter is
operating.
The ticket securing pin in a printer head must be in the
down or locked position when the meter is operating.
Meter calibration is accomplished by adjusting the
calibrator dial or knobs. See calibration section.
Meters equipped with G, ATG or AMR calibrators can be
operated in either direction.
If accuracy or repeatability cannot be obtained, or if
excessive noise is present, it is an indication that meter
should be disassembled for inspection and/or repair.
Probable causes for inaccuracy and non repeatability
are:
1.
Excess clearances allowing slippage.
2.
Rotor not turning freely.
If rotor does not turn freely, adjust for end clearance
after removal of outer cover and before disassembly of
meter. See Rotor Adjustment End Clearance.
Excessive noise may be an indication of worn parts.
Before any disassembly of meter:
1.
Be sure that the meter is being operated within
the proper flow rate (refer to the name plate).
2.
Remove and check calibrator to be sure that it is
operating properly.
Calibrator should turn smoothly when top coupling is
held and bottom coupling is turned counter-clockwise.
Uneven or rough operation indicates presence of burrs
or foreign material.
Lack of torque or too much side-play in shaft is
indication of worn bearings.
ACCESSORIES AND PROTECTIVE DEVICES
Air Eliminators
The presence of air or vapor in a liquid stream being
measured by a positive displacement meter will cause
inaccurate measurement. And under some conditions
damage to the meter. If there is a possibility of air
entering the stream, an air eliminator or deaerator of
adequate size should be installed upstream of the
meter. In some cases, it may be necessary to install a
back pressure valve between meter and air eliminator to
permit the air eliminator to operate efficiently.
Flow Control
In any system where there is a possibility of flow
exceeding the maximum rated capacity of the meter, a
flow limiting valve or device should be installed
upstream of the meter.
Strainers
A strainer of adequate size and with proper mesh
basket, should be installed upstream of the meter to
protect it from foreign material.
A9-36
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