AW Gear Meters GEAR METERS - Manual (Page 7)

Positive Displacement Flow Meters
Operation and Installation Manual
6
Location
It is important to make sure that the flowmeter is always full of fluid and never partially filled. Do this by
making sure there is always a small amount of backpressure on the meter, usually 2 to 5 psi minimum.
Create backpressure by making sure there is some flow restriction downstream from the flowmeter
such as a check valve, regulator, or piping rising above location of flowmeter. See Figure 1.
Backpressure from control valving is beneficial for stable running. In similar fashion, if a flowmeter is
installed with fluid flow in a downward direction, the fluid cannot exit the flowmeter directly into a
container with no restriction due to the fact the meter will not be full of fluid, causing inaccurate
measurement.
Eliminate all dirt, debris and metal shavings from the piping, as the liquid must be free from any particles
larger than what the manufacturer’s specifications allow. Install any recommended filtration before
operation, as potential plugging most often occurs at startup.
Installing a Bypass
If possible, install a bypass around the flow meter, and flush existing piping with the appropriate liquid
before first use. See Figure 1.
Pickup Sensor
Review the pickup instructional guide prior to installation.
Location
Locate the pickup and wiring away from A/C motors, actuators, heaters, relays, etc. Use only shielded
cable and if possible, a dedicated power supply for the electronics. If sharing power with other devices
in the system, be aware that power-draw spikes from other equipment could cause a surge into the
sensor, which in turn can cause sensor to give erroneous pulses. Ensure clean power supplies that utilize
a true earth ground. Install Intrinsic Safety Barriers if the circuit is intended to be intrinsically safe.
Caution