Multistage pump is a type of centrifugal pump in which the inlet and outlet sections and the middle section are combined through a pull rod. Its output water pressure can be very high, and it also relies on the rotation of the impeller to obtain centrifugal force, thereby transporting materials. When the gas density reaches the working range of the mechanical vacuum pump, it is extracted, thereby gradually achieving high vacuum.

Multistage pumps achieve suction, compression and exhaust by changing the volume of the pump cavity, so they are variable-volume centrifugal pumps. 

Multistage pumps are a type of centrifugal pump. They also rely on the rotation of the impeller to obtain centrifugal force, thereby transporting materials. When the gas density reaches the working range of the mechanical vacuum pump, it is extracted, thereby gradually achieving high vacuum.

Multistage pumps can be used in many industrial sectors such as petroleum, chemical engineering, machinery, mining, light industry, medicine and food. In many technological processes of industrial production, such as vacuum filtration, vacuum water drawing, vacuum material conveying, vacuum evaporation, vacuum concentration, vacuum rehumidification and vacuum degassing, multistage pumps are widely applied. Water ring pumps can extract flammable and explosive gases. Besides, they can also extract gases containing dust and water. Therefore, the application of water ring pumps is increasing day by day.