Positive Displacement Flow Meters

Addmas offer Positive displacement meter , which is a type of flow meter that requires fluid to mechanically displace components in the meter in order for flow measurement. Positive displacement (PD) flow meters measure the volumetric flow rate of a moving fluid or gas by dividing the media into fixed, metered volumes (finite increments or volumes of the fluid). A basic analogy would be holding a bucket below a tap, filling it to a set level, then quickly replacing it with another bucket and timing the rate at which the buckets are filled (or the total number of buckets for the “totalized” flow). With appropriate pressure and temperature compensation, the mass flow rate can be accurately determined.
These devices consist of a chamber that obstructs the media flow and a rotating or reciprocating mechanism that allows the passage of fixed-volume amounts. The number of parcels that pass through the chamber determines the media volume. The rate of revolution or reciprocation determines the flow rate. There are two basic types of positive displacement flow meters.

  • Oval Gear Meter
  • Rotating Piston

Features :

  • Positive displacement flowmeters are very accurate and have high turndown.
  • It can be used in very viscous, dirty and corrosive fluids and essentially require no straight runs of pipe for fluid flow stream conditioning though pressure drop can be an issue.

Application :

  • Widely used in the custody transfer of oils and liquid fluids (gasoline) and are applied on residential home natural gas and water metering.
  • PD flow meters work best with clean, non-corrosive, and non-erosive liquids.
  • Because of their high accuracy, PD meters are widely used at residences to measure the amount of water used. Other applications include: chemical injection, fuel measurement, precision test stands, high pressure, hydraulic testing, and similar precision applications.