Dry vacuum pump is a relative liquid ring pump, without sealing coolant in the working chamber.
Since there is no sealant and the exhaust pressure is greater than the atmospheric pressure, the dry vacuum pump can condense the exhaust gas from the exhaust side.
The dry vacuum pump includes piston, roots pump, claw type and twin screw type.
Dry screw vacuum pump has the advantages of high efficiency, long life, low cost and so on. It has gradually become the most widely used dry vacuum pump.
The dry screw vacuum pump rotor is a small, non contact screw, which drives the gas to drive the exit through the synchronous gear drive.
It has the advantage of being:
(1) work at full speed under atmospheric pressure and extreme vacuum;
(2) single stage can reach high vacuum, the ultimate pressure can reach 10 Pa;
(3) no oil or water contact gas in the working chamber of pump;
(4) the rotor does not contact each other to reduce wear;
The rotor can be coated with fluorine, nickel and other anti-corrosion layer;
(5) the gas passages in the pump are short and the exhaust is fast;
(6) it can be operated alone or as a front pump.
Dry screw vacuum pump has equal pitch and variable pitch, also called external pressure screw and internal pressure screw.
Compared with the screw pump, the exhaust temperature is low and the efficiency is high.