Since 1985, we’ve supplied businesses worldwide with a large selection of durable, industry-standard Positive Displacement flow meters.

For the last four decades, we’ve built a huge catalogue of products to suit your every need organised by flow ranges – from our standard range of flow meters (popular in the UK, EU and US), to our bespoke range of customisable flow meters that can be adjusted to suit to almost any flow application. You can read more on our standard flow meters here.

The VFF range is ideally suited to low flow/high pressure services such as those found in chemical injection, hydraulics and subsea.

What is a VFF Flow Meter?

In the VFF the rotor is basically a disc shape with an annular groove on its underside capable of holding and transporting flow from the chamber inlet to the outlet. Some fluid is also transported in a cavity formed between the rotor outside wall and the chamber wall. A centre ‘peg’ under the rotor is constrained to run in a circular groove in the body. A web (or plate) in the body is engaged with a slot in the rotor and this modifies the rotation to that of an oscillation as flow passes. It is this oscillation that produces the compartmentation of the fluid into ‘positively displaced pockets’. The top of the rotor is equipped with a powerful magnet directly above the ‘peg’ that is on the underside and so this also has a circular path which allows it to engage and disengage a reed switch sensor located in the top cap above.

Pressure Balanced Chamber (PBC)

This describes the rotor and the chamber in which it rotates. It’s a separate item that can be removed for inspection and calibration. A side benefit is that it enables pressure independent measurement.

Key Benefits:

  • No distortion of the chamber at higher pressures
  • No measurement inaccuracy due to pressure
  • Enables selection of optimal materials for the chamber to match the rotor
  • PVD coated stainless steel
  • Enables selection of optimal materials for the pressure vessel. i.e. super duplex stainless steel
  • Enables construction of a duplex bodied flow meter – duplex material does not lend itself to the tolerances required in machining

All VFF flow meters are custom calibrated across the customer specified min – max flow conditions and working viscosity. The minimum flow rates achievable are dependent on fluid viscosity.

Typical VFF Application?

♦ Chemical Injection ♦ Hydraulics ♦ Wax Dispersant ♦ Corrosion Inhibitor ♦ Subsea Control fluid ♦ PIB ♦ Scale Inhibitor ♦ Subsea flow ♦ Ashalphtene Dispersant ♦ Pour Point Depressant ♦ Demulsifier


±1% of reading, requires linearisation

Pressure Rating

Dependent on Connection size and rating

Temperature Rating

-40°C to +100°C dependent on material and instrument; +75°C with FlowPod in a Hazardous Area

Viscosity Range

0.5 to 100,000 cP or greater

Recommended Filtration

A 100 micron filter is advisable for 100% long life serviceability

VFF Flowmeter Datasheet PDF Download
VFFs for Chemical Injection PDF Download
VFF meters for 20,000psi - and higher PDF Download
FlowPod Exd-Rated Flow Display Datasheet PDF Download
VFF Quick Start Instructions PDF Download
VFF Installation and Maintenance Manual PDF Download
FlowPod Installation, Operating Instructions including Ex certificates PDF Download
Wiring VFF FlowPod - 2 wire PDF Download
Wiring VFF FlowPod - 4 wire PDF Download
Return to Factory form (RTFF) (return to KEM Germany for service and calibration) PDF Download