Types and characteristics of vacuum pumps

A vacuum is a gas in which the molecular density of a gas is lower than the standard pressure. The degree of vacuum is a measure of the thinness of a gas, and its most direct physical quantity should be the number of molecules per unit volume. But because of the history, the vacuum is usually expressed as the pressure of the gas, and the lower the pressure of the gas is, the higher the vacuum. There are two types of vacuum pumps.

(1) reciprocating vacuum pump:

Reciprocating vacuum pump is one of the main equipment to obtain vacuum. Used to remove air and other gases from closed container or reaction pan, not suitable for corrosive gas or gas with hard particle ash powder. W-type vacuum pump has the advantages of small volume, simple maintenance and long service life of valve disc, etc.

(2) rotary vane vacuum pump:

The type 2X rotary vane vacuum pump is a bipolar structure volume vacuum pump, which is rotated at high speed by the rotor with rotary vane installed eccentrically, so that the volume of the pump chamber changes continuously and the pumping function is completed. The pump is equipped with a pneumatic valve. When a small amount of water vapor is contained in the pumped gas, the valve is opened to inject air into the exhaust chamber of the pump. The type 2X vacuum pump can be used as the main pump separately, or as the front stage pump of the booster pump, diffusion pump and molecular pump.

The 2XZ rotary vane vacuum pump is a two-stage direct connection structure, and its pumping principle is the same as the 2X type. This pump has the advantages of small volume, light weight, low noise, easy to start and move, and is suitable for laboratory use. The 2XZ type vacuum pump can be used independently, and can also be used as the front stage pump and maintenance pump of the booster pump, diffusion pump and molecular pump. The pump is not suitable for corrosive gas and gas containing granular ash powder.