Positive Displacement Meters

Meters in which spring- or cam-driven vanes mounted on a rotor sweep a precise volume of liquid through the measuring chamber each revolution. Widely used for crude oil and refined-product custody transfer and loading-rack service due to high accuracy across moderate viscosities.

Meters using two intermeshing oval-shaped gears that trap a fixed volume between each gear and the chamber wall as they rotate. Favored for viscous fluids, additives, lubricants, and chemical injection because accuracy improves with increasing viscosity.

Meters with two contoured rotating lobes or a rotating piston that carry discrete fluid volumes around the chamber. Used for high-throughput liquid product transfer and gas measurement where low pressure drop is required.

Meters employing two intermeshing helical rotors that displace a constant volume per turn. Their non-pulsating, low-friction action suits high-flow pipeline product measurement and clean refined hydrocarbons.

Reciprocating-type meters in which a single disc wobbles (nutates) within a conical chamber, displacing a set volume each cycle. Common in lower-cost, lower-rate fuel dispensing and water service.

Gas-service PD meters that use flexing diaphragm chambers or rotating impellers to displace fixed gas volumes. Used for natural gas custody and utility metering, built to ANSI B109 and equivalent standards.

Reference volume devices such as bidirectional pipe provers, compact (small-volume) provers, and master meters used to determine the PD meter factor. Required to maintain traceable accuracy for fiscal and custody-transfer measurement.

Mechanical counters, pulse transmitters, electronic preset/batch registers, temperature compensators, and flow computers that convert meter cycles into corrected volume. Enable batch loading, ticketing, and remote data acquisition.