Flow Meters › Positive Displacement Flow Meters
Positive displacement flow meters trap a known volume of fluid and count how many times it passes, so they read by volume directly rather than from velocity. That makes them accurate on viscous and changing fluids, and able to work with no straight pipe run. The oval gear type is the most common, for oils and other thick, clean liquids.
Positive displacement flow meters
Oval Gear Flow MeterPositive displacement metering for diesel, fuel and lube oil, resin, and other viscous liquid. DN10 to DN200, 0.5 percent of reading.
Spiral Rotor Flow MeterTwin helical rotors for heavy, high-viscosity oil at flow. Low pulsation, DN15 to DN200.
Rotary Gas MeterRoots-type PD gas meter for natural gas custody and utility billing, corrected to standard volume.
Gear Flow MeterSpur-gear PD meter for micro and small flow of viscous, high-pressure liquid. From 0.1 L/h.
Choosing a positive displacement flow meter
| If you need | Consider |
|---|---|
| Viscous oil or resin | Oval gear flow meter, cast iron or stainless, normal or high-viscosity rotor |
| Corrosive liquid | Oval gear in 304 or 316L stainless |
| Higher pressure | Oval gear in cast steel, with the pressure rating set to the service |
| A local total, no power | Mechanical pointer register; add an LCD and pulse where a signal is needed |
| Clean, low-viscosity liquid | A turbine flow meter is usually the better fit at higher flow |
Tell us the fluid, the viscosity, and the flow range and we set the build.
FAQ
What is a positive displacement flow meter?
It is a meter that traps a known volume of fluid and counts how many times that volume passes, rather than inferring flow from velocity. Because it measures volume directly, it stays accurate on viscous and changing liquids and needs no straight pipe run.
What types are there?
The oval gear meter is the most common, with two meshing oval gears. Others include the rotary piston and the nutating disc. For viscous oils and resins, the oval gear type is the usual choice.
How accurate are they?
An oval gear meter reads to 0.5 percent of reading as standard, and 0.2 percent on request. The accuracy holds across viscosity and temperature, which is the main reason to choose displacement metering for thick fluids.
Request a quote
Tell us the fluid, the viscosity, the size, and the flow range, and we set the meter, the material, and the register.