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Dry Screw Vacuum Pumps

Dry compressing screw vacuum pumps belong to the group of positive displacement pumps. Two screw rotors arranged in parallel which are synchronised by means of a gear revolve in opposite directions in the pump housing. The gas which is to be pumped is trapped inside the pump and compressed in the direction of the exhaust by the rotary movement of the screws. Dry compressing screw vacuum pumps offer a constant pumping speed across a broad pressure range and low ultimate pressures, but are quite involved engineering-wise. They are, for example, well suited for continuous distillation processes which require a low pumping speed, and they are well suited as a backing pump for Roots vacuum pumps. In processes involving traces of solids and/or vapours which have a sublimation tendency, screw vacuum pumps are only of limited service.