1、water ring vacuum pump
The impeller’s rotation of the pump to form the water ring. Owing to the Rotor rotates ecentrically to make the volume between the water ring and vanes changed periodically. The mechanical vacuum pump using this kind to pump air is called water ring pump.
2、Reciprocating vacuum pump
This mechanical vacuum pump is using the piston’s to and pro movement to pump the air.
3、Oil seal mechanical vacuum pump
This mechanical vacuum pump is using the oil to keep seal. It can class the Statory type, Rotary type, Rotary Piston etc.
4、Roots vacuum pump
It has a pair of shoes shape Rotor which rotates high speed.This pump can not use alone, the fore stage must assemble the oil seal pump or water ring pump that can aspirate the air directly.
5、Turbo molecule vacuum pump
It has a high speed impeller,when the air molecule meets the high speed turbo vanes to push to the outlet, then is pumped by the fore pump.
6、Oil diffusion vacuum pump
The high speed steam current is spouted out from the outlet port of the diffusion. Under the molecule current, the air molecule diffuses into the steam current continually, and carries by the steam to the outlet, then is pumped by the next stage in turn, at last, is pumped out by the fore pump.
7、Low temperature vacuum pump
The vacuum pump is using the low temperature surface that under the 20K to absorb the air.
8、Cryogenic well（water cooled intercepting plate）
It is set between the container and pump. Using as the device to absorb the air and collect the oil steam.
9、Gas ballast valve
To open a hole in the compressed room of the oil seal vacuum pump and install a adjust valve.When turn on the valve and adjust the intaking volume, the Rotor turns a definite position, the air passes the hole to enter the compressed room, then the compressure rate is reduced. So that most of the steam can not coagurate to pump outside of the pipe with the aerifed air. Possess the function above valve is called gas ballast valve.