Rotary screw vacuum pumps
AssigneeEdwards Limited
InventorNigel Paul Schofield
Life of this patent
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Abstract
A rotary screw vacuum pump 10 comprises a housing 12 that has a lower pressure inlet region 14 and a higher pressure outlet region 16 and two intermeshing screws 18 disposed in the chamber and configured to cooperably rotate to compress a gas in working chambers formed between them and the housing while pumping the gas from the lower pressure inlet region to the higher pressure outlet region. The housing 12 has a least one liquid inlet 20 to admit a sealing liquid to seal the working chambers. The intermeshing screws 18 comprise Quimby-type screws.
Claims21
A rotary screw vacuum pump comprising:
- a housing having a lower pressure inlet region and a higher pressure outlet region;
- and
- two intermeshing screw rotors disposed in the housing and configured to cooperably rotate to compress a gas in working chambers formed between said screw rotors and said housing while pumping said gas from said lower pressure inlet region to said higher pressure outlet region,
- wherein said housing has at least one inlet to admit a liquid into said housing to seal said working chambers, and
- said intermeshing screw rotors comprise Quimby-type screw rotors.
A rotary screw vacuum pump comprising:
- a housing having walls defining a rotor chamber;
- two intermeshing screw rotors in said rotor chamber that are configured to cooperably rotate to compress a gas in working chambers formed between respective threads of said screw rotors and at least one said wall, each said thread having a crest, a root, a first flank and a second flank, said first and second flanks extending from said crest to said root and said second flank comprising a concave cross section;
- an exhaust port to receive compressed gas from said working chambers and provided with an exhaust valve operable to prevent gas entry to said rotor chamber via said exhaust port;
- and
- a liquid feed system operable to feed a liquid into said rotor chamber to seal said working chambers.
(canceled)
Dependencies are inferred from the claim text.