Oval Gear Flow Meter

The oval gear flow meter is a type of positive displacement flowmeter. Fluid forces the meshed gears to rotate; each rotation corresponds to a fixed volume of fluid. Counting the revolutions totalizes volume, and the rate is proportional to flow.

Oval Gear Flow meter Overview

Oval Gear Flow Meters can be used in a wide range of media applications and are designed for clean process fluids. No flow conditioning allows for superior design flexibility. Maintenance is minimal and changing viscosities do not affect meter accuracy. The cost of ownership can be very attractive compared to other flow technologies while providing highly accurate and repeatable results. Oval Gear Meters are mechanical meters and should not be used in fluids with non-soluble particulate. This is a liquids only meter – gases are not suitable.

Oval Gear Flow meter Principle

The oval gear flow meter comprises oval-shaped, geared rotors that rotate within a housing of specified geometry. Fluid differential pressure causes the intermeshing gears to rotate, trapping a ‘pocket’ of fluid between the gear and the outer housing and subsequently emptying the fluid pocket into the downstream flow.
Capillary action of the metered fluid forms a liquid seal. Each ‘pocket’ holds a precise and known volume of fluid so counting the pocket frequency gives a measurement of the volumetric flow rate. This is typically achieved by embedding magnets in the rotors, which then actuate a reed switch or provide a pulse output as they rotate.



Mass & Volumetric flow monitoring of most conductive liquids

  • Traditional proven flow technology
  • Simple to install
  • No straight pipe runs are required so flow meters can be installed in restricted areas

Easy to Install, lots of field installation options

Rugged, long-lasting design for the toughest applications


Pipe diameter:1/4″inch to 8″inch



Pressure rate:≤10 Bar,≤16 Bar,≤25 Bar,≤40 Bar

Temperature:≤80℃(Normal),≤300℃(High temperature)



Ambient temperature:
Operating: -20° to 60°C
Storage: -40° to 65°C


Power supply:24VDC 500mA,3.6V Battery,Mechanical

Output signal:

  • 4-20mA
  • Pulse
  • User-definable pulse output for totalized flow

Digital communications: RS485, Hart

Hazardous-Area Location Enclosure



Filed indicator

High temperature

steam tracing

Resettable counter



  • inline oval gear Flow meter 1“ inch drawing
  • inline oval gear Flow meter 1.5“ inch drawing


  • RS485 Protocol
  • Hart Protocol

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