River water pump it is the use of the volume of the pump chamber to complete the cycle of the suction and exhaust to achieve the purpose of pumping the vacuum pump. Gas in the discharge pump chamber before being compressed. This pump is divided into two kinds of reciprocating and rotary type.

1, reciprocating vacuum pump

Use of pump chamber piston reciprocating motion, the gas inhalation, compression and discharge. Also known as piston type vacuum pump.

2, rotary vacuum pump

Gas suction, compression and discharge through the rotating movement of the rotor part of the pump. It is roughly classified as follows:

1) the oil seal type vacuum pump is the use of vacuum pump to seal the gap between the moving parts of the pump to reduce the harmful space of a rotary variable capacity vacuum pump. The pump is usually equipped with a gas ballast. It mainly includes the rotary vane vacuum pump, vacuum pump stator, vacuum pump, vacuum pump trochoid etc..

2) liquid ring vacuum pump with a plurality of blades of the rotor eccentric loaded in the pump casing. When it is rotating, the working fluid is pumped into the pump shell and the pump casing is formed and the liquid ring, the liquid ring and the rotor blade form a small rotary variable capacity absorbing and exhausting cavity. The working fluid is usually water or oil, so it is also called a water ring vacuum pump or an oil ring vacuum pump.

3) a dry vacuum pump is a variable capacity vacuum pump without oil (or liquid). Since the dry vacuum pump cavity does not require working liquid and, therefore, is applicable to non oil vacuum cleaning technology in semiconductor industry, chemical industry, pharmaceutical industry and food industry and so on.