AW Gear Meters GEAR METERS - Manual (Page 12)

Positive Displacement Flow Meters
Operation and Installation Manual
11
Flow Meter Do’s and Don’ts
DO Leave flushing fluid in the lines overnight or during extended off-times. This keeps internals
wet, prevents residual fluids from drying, and facilitates startups.
DO Follow the Maintenance Guide instructions when opening and cleaning a flow meter. During
cleaning, separate the gears from the shafts. On carbide bearings, clean inside the center of the gear
bearing and on the outer surface of the shafts at the point where the gear rotates on the shaft. Apply a
suitable lubricating fluid before closing the flow meter. After tightening the bolts, a short squirt of shop
air will briefly spin the gears, which should be easily audible.
DO Install and maintain filters. Install the recommended filter to eliminate potential plugging.
Should plugging occur, the flow meter will still pass fluid but with no signal output.
DO Check electrical compatibility between the flow meter’s output signal and the input of the
PLC. If signals are not being detected at startup, first check wiring and electrical compatibility.
DO Verify reliable grounding of electrical parts, as per installation guidelines. A dedicated power
supply is recommended. Voltage spikes on shared power lines, negligent grounding and sloppy wiring
will likely produce erratic readings and chronic maintenance.
DO Install the flow meter immediately upstream of the regulator or control valve. The control
valve provides backpressure, which stabilizes the flow.
DON’T Allow air into the flow meter. Always keep the flow meter internally wet.
DON’T Dry lines using pressurized air. Flow meters are designed to flow liquids. Close meters to air
except when air is part of an automated purge cycle. Do not dry lines after purging.
DON’T Allow materials to dry inside the flow meter. When a flow meter is removed from the line
during maintenance, clean the internals immediately, lubricate the gears, and cap the fluid ports.
DON’T Over tighten the pick-up sensor beyond hand tight. When installing the pickup sensor, turn it in
lightly to a hand-tight torque. Do not use a wrench on the pickup as over tightening may cause a dimple
of metal under the sensor nose to protrude into the gear cavity and interfere with the gear’s rotation.
DON’T Use water or solvent for calibration or test purposes. Water or solvent may not turn the gears
at low flow and may leave the impression that the flow meter is not functioning. A calibration factor (k-
factor) is issued with the flow meter, which is valid for most fluids except water or equivalent viscosities.