The lower end of the rotor is excluded and the rotor rotates once to exhaust. A sealing structure is formed on the surface of the rotor and the pump body, and the leakage of the clearance of the rectangular section is less. Therefore, a higher compression ratio can be obtained. The compression ratio and pumping speed of the pump are related to the guide angle of the rotor, the clearance between the rotor and the pump body, the meshing rate, the number of cycles, the diameter of the rotor and the rotating speed.

Because of its large number of cycles, higher compression ratio than the screw type and lower pumping speed, the pump can be pumped from atmospheric pressure to the limit pressure of 10-1Pa. Pumps with pumping speed of 40-80m3/h are available on the market.

The larger the angle of the piston for the rotation of the non-oil supply level is, the larger the distance between the upper end of the plunger and the inclined side of the opening of the return hole of the plunger sleeve is, and the larger the oil supply is. If the angle of the piston rotation is small, the oil break starts earlier and the oil supply is smaller. When the diesel engine stops, the oil must be cut off. Therefore, the longitudinal groove on the plunger can be transferred to the oil return hole directly opposite the plunger sleeve. At this time, during the whole plunger stroke, the fuel in the plunger sleeve has been flowing back through the longitudinal groove and the return hole, and there is no pressure process, so the fuel supply is equal to zero. When the plunger rotates, the fuel supply is adjusted by changing the end point of the fuel supply.

The method of regulating oil quantity by dry vacuum pump is introduced in this paper. It is necessary to know all kinds of technology and operation methods of the product for operators and factory application.

In dry vacuum pumps, suction valves and exhaust valves are very important parts and vulnerable parts. Their working quality directly affects the limit pressure, pumping rate, power consumption and operation reliability of reciprocating pumps.