Positive displacement (PD) meters are volumetric flow measurement instruments ideal for low flow rates, highly viscous fluids, and measurement of flows involving starts and stops or pulsing. Positive displacement meters are similar in design to the gear pump.  The principle of operation is reversed however; instead of the gears driving the fluid, the fluid drives the gears.  A non-intrusive hall-effect sensor detects the movement of the gear and as each gear tooth passes the sensor, a square wave pulse is produced and a discrete volume of liquid is measured. The resulting pulse train is proportional to the actual flow rate and provides a highly accurate representation of the fluid flow.
Positive displacement meters come in a variety of styles, and we carry three of them… read more