rotary vane pump working principle

Rotary vane pump is mainly composed of pump body, rotor, rotary vane, end cover, spring and so on. A rotor is eccentrically installed in the cavity of the rotary vane pump. The outer circle of the rotor is tangent to the inner surface of the pump cavity (there is a small gap between them). Two rotary vanes with springs are installed in the rotor groove. When rotating, centrifugal force and spring tension keep the top of the rotor in contact with the inner wall of the pump chamber. Rotor rotation drives the blade to slide along the inner wall of the pump chamber.

The two rotating vanes divide the crescent-shaped space enclosed by the rotor, pump chamber and two end caps into three parts: A, B and C, as shown in the figure. When the rotor rotates in the direction of arrow, the volume of space A connected with the suction port increases gradually and is in the process of suction. The volume of the space C connected with the exhaust port is gradually shrinking, and it is in the exhaust process. The volume of B in the middle space is also gradually decreasing, and it is in compression process. Because the volume of space A increases gradually (i.e. expands), the pressure of gas decreases, and the pressure of gas outside the inlet of the pump is stronger than that inside space A, the gas is inhaled. When space A is isolated from the suction port, that is to say, when it moves to space B, the gas begins to be compressed, the volume gradually reduces, and finally communicates with the exhaust port.

When the compressed gas exceeds the exhaust pressure, the exhaust valve is pushed open by the compressed gas, and the gas is discharged into the atmosphere through the oil layer in the tank. By continuous operation of the pump, the purpose of continuous pumping is achieved. If the exhausted gas passes through the airway and transfers to another stage (low vacuum stage), it is pumped out by the low vacuum stage, and then compressed by the low vacuum stage and discharged into the atmosphere, a two-stage pump is formed. At this time, the total compression ratio is borne by the two stage, thus raising the limit vacuum degree.