Vane pump: Vane pump is a positive displacement pump in which slotted rotor splinted to a drive shaft the rotor rotates between closely fitted side plates that are inside of an elliptical or circular shaped ring.
Fig. Vane pump
As the rotor rotates centrifugal forces causes the outer edge of each vane to slide along the surface of the housing cavity. Pumping chambers are formed between succeeding vanes carrying oil from the inlet to the outlet. A partial vacuum is created at the inlet as the space between vanes increases. The oil is squeezed out at the outlet as the pumping chamber’s size decreases.
A vane pump is the only design that has automatic wear compensation, built in. As wear occurs, the vanes simply slide farther out of the rotor slots and continue to follow a ring contour. Thus efficiency remains high throughout the life of the pump.
They are used for higher flow and low pressure applications.