VFF

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