A screw vacuum pump consists of two screws, one with right-hand thread and the other with left-hand thread. Both screws turn in the compression housing without friction and at very tight clearances. They are synchronized via a precise gear. The compression housing and the specially shaped screws form the compression chambers. Due to the opposite rotation of both screws, the chamber connected with the suction port is enlarged and the gas is transported into the compression chamber. Then the chamber moves axially from the suction side to the pressure side. During transportation, plenty of gas increases in the chamber due to bigger flow. On the pressure side, the chamber is moved against the axial housing wall and the volume is reduced gradually until the front surface of the screw opens the pressure channel and the pre-compressed gas is discharged through the pressure connection.
The chamber is full of vacuum pump oil, which plays a role in lubrication, sealing and cooling. After oil-air mixture discharged out of the chamber undergoes three-level oil-air separation, clean gas is exhausted to the atmosphere. After being cooled by the air cooler, lubricating oil is injected to the vacuum pump chamber again for recycling.
