Vacuum Pump Common Parameters

Vacuum pump refers to a device or equipment that uses mechanical, physical, chemical methods to pump air from the pumped container to obtain a vacuum. Generally speaking, a vacuum pump is a device that uses various methods to improve, generate and maintain a vacuum in a closed space.

According to the working principle of vacuum pumps, vacuum pumps can basically be divided into two types, namely gas capture pumps and gas transmission pumps. It is widely used in metallurgy, chemical, food, electronic coating and other industries.


  1. Maximum foreline pressure

The foreline pressure that can damage the pump is exceeded.


  1. Ultimate pressure (ultimate vacuum) (unit: Pa/Mpa/mmHg)

The pump is equipped with a standard test cover and works according to the specified conditions, and tends to a stable minimum pressure under the condition of normal operation without introducing gas. That is, the lowest stable pressure that can be reached at the inlet end of the vacuum pump after full exhaustion.


  1. Compression ratio

The ratio of the outlet pressure of the pump to the inlet pressure of a given gas.


  1. Starting pressure

The pump starts without damage and has a pumping pressure.


  1. Pre-pressure

The discharge pressure is lower than the outlet pressure of a vacuum pump at atmospheric pressure.


  1. Maximum working pressure

The inlet pressure corresponding to the maximum pumping volume. Under this pressure, the pump can work continuously without deterioration or damage.


  1. Suction capacity(“Q” unit: Pa·m3·S-1, Pa·L·S-1)

Gas flow volume through the pump inlet. When the pump is equipped with a standard test cover and works under specified conditions, the ratio of the gas flow through the test cover to the equilibrium pressure measured at the specified position on the test cover referred to as the pumping speed of the pump. That is, under a certain pressure and temperature, the volume of gas drawn by the vacuum pump from the pumped container in a unit time.

In summary, the pumping speed and ultimate pressure of the vacuum pump are the most important parameters for selecting a suitable vacuum pump.

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