Rotary vane pumps: Technical overview

This article aims to describe the main features of the vane pump technology, how it works, its advantages and disadvantages, and where it is most commonly used. Finally, we will briefly mention the Fluid-o-Tech vane pumps.

Below is a brief summary of the contents:

• How does a vane pump work

• Main fields of application

• Advantages and disadvantages of the rotary vane pumps

• The Fluid-o-Tech vane pumps

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How a rotary vane pumps works

Rotary vane pumps are a type of positive displacement pump. Like all positive displacement pumps, the flow rate is always directly proportional to the speed.

Vane pumps are available with different types of vane: sliding, flexible, oscillating, rotating, and external vanes. The vane pumps are known for their dry-priming, easy maintenance, and good suction characteristics throughout the life of the pump.

Despite the different configurations, most vane pumps operate according to the same general principle as described below.

A splined rotor is supported eccentrically in a cycloidal cam. The rotor sits close to the cam wall to form a crescent-shaped cavity. The rotor is sealed in the cam by two side plates. The vanes or blades fit into the rotor cavities. When the rotor rotates and fluid enters the pump, the centrifugal force, the hydraulic pressure, and/or the pushrods push the vanes towards the housing walls. The tight seal between the vanes, the rotor, the cam, and the side plate makes this technology powerful for good suction, which is common to the vane pumping principle.

The housing and cam force the fluid into the pumping chamber through holes in the cam (small red arrow on the bottom of the pump). The fluid enters the pockets created by the vanes, the rotor, the cam, and the side plate.

As the rotor continues to spin, the vanes sweep the fluid to the opposite side of the crescent where it is squeezed through the cam discharge holes as the vane approaches the point of the crescent. The fluid then exits through the discharge port.

In addition, this technology is available with both direct and magnet drive. This latter option removes the shaft seal by introducing a magnetic coupling.

Main applications of rotary vane pumps

The rotary vane pump is very versatile and can be used in a variety of sectors and applications, from dosing to transferring and repressurizing fluids. Depending on the choice of materials, rotary vane pumps can handle a wide range of clean fluids.

Advantages and disadvantages of the vane pumps

Advantages of rotary vane pumps:

• Delivery of a stable, low-pulsation flow rate

• Capable of generating a high differential pressure

• Operate in both directions of rotation

• Compensate for wear through vane extension

• Self-priming design

• Low noise and vibration levels

Disadvantages of rotary vane pumps:

• Not suitable for high pressures

• Not suitable for viscous fluids

• Not suitable for abrasive fluids

Fluid-o-Tech rotary vane pumps

Fluid-o-Tech is able to supply a wide range of rotary vane pumps covering a variety of applications in different sectors. In stainless steel, low-lead brass, technopolymer, direct coupled, magnetic or electromagnetic drive at variable speed, our pumps cover a flow rate range from 30 to 2200 l/h at pressures up to 18 bar. The built-in safety valve, available on request, limits the pressure to protect the pump and the hydraulic circuit.

The Fluid-o-Tech rotary vane pumps, WRAS or NSF certified for use with potable water, are the reference choice in the market of espresso machines and beverage dispensers for professional use.

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