Rotary abutment meters are another form of positive displacement flow meter. As there is no metal contact within the chamber they have a long service life, also maintaining accuracy too. They have a wide viscosity range making them suitable with many types of fuels & lubrication fluids. The rotors are connected to timing gears, so each time a rotor turns, the displaced volume is transferred to the register and the controller calculates the flow.

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There is no metal-to-metal contact between the rotors and housing walls, which prolongs the life of the flowmeter.

Advantages:

• Sweeping action of vanes prevents buildup of sediment and keeps compartment clean.
• Wide choice of construction materials.
• High accuracy and repeatability.
• Low pressure drop over entire range of flow measuring capabilities.

Disadvantages:

• Relatively complex design increases cost.