Any machine that takes out gas from the equipment and makes the inside of the equipment reach a vacuum is called vacuum aspirator or vacuum pump. From the structure of the vacuum pump can be roughly divided into: reciprocating vacuum pumps, rotary vacuum pumps and jet vacuum pumps. 1, reciprocating vacuum pump Reciprocating vacuum pump is suitable for pumping non-solid particles, non-corrosive gases. This vacuum pump pumping speed larger vacuum degree higher. It is widely used in chemical plants. However, its complex structure, large amount of maintenance. 2, water ring vacuum pump. Water ring vacuum pump is a rotary vacuum pump. 3, jet vacuum pump. Jet vacuum pumps use a higher pressure working fluid to deliver another fluid.