The pumping rate of the vacuum pump refers to the volume of gas discharged per unit time. The common unit is liters second (L S)

1. Nominal pumping speed
The nominal pumping speed is the label pumping speed of the rotary vane pump. According to the national standard, the nominal pumping speed of the rotary vane pump has been standardized.

2. Geometric pumping speed
The geometric pumping speed is the geometric volume discharged per unit time of the rotary vane pump at the rated speed. It is related to the volume of the suction chamber at the end of the suction, the speed of the rotor, and the number of times of suction and discharge during one rotation of the rotor.

In order to make the pump fully inhale, the closed suction cavity should be the largest at the end of the inhalation. Considering the existence of backflow, leakage and resistance of the intake passage in the pump. In order to ensure that the pump can reach its nominal pumping speed, the geometric pumping speed should be 1.1 to 1.15 times the nominal pumping speed during design. Increasing the speed of the pump can increase the pumping speed and reduce the geometric size of the pump.

3. Actual pumping speed
The actual pumping speed is the actual measured pumping speed of the rotary vane pump. It is a function of the inlet pressure. The pump maintains a certain pumping speed within a certain pressure range. When the inlet pressure of the pump is low, its actual pumping speed will decrease. When the ultimate pressure of the pump is reached. The actual pumping speed is zero.