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US 9,869,317 B2Granted
Pump
AssigneeEdwards Limited
InventorNigel Schofield
Life of this patent
Estimating the term…
Abstract
The present invention relates to a multi-stage vacuum pump having a plurality of compression stages 12, 14, 16, 18 20 and a booster stage 22. The pump 10 is arranged to pump a chamber 24. The pumping stages include respective rotors supported for rotation on one or more common drive shafts 26. A recirculation valve 28 is associated with the booster stage 22 for selective recirculation of pumped fluid from an outlet 32 to an inlet 30 of the booster stage above a predetermined pressure.
Claims18
A multi-stage vacuum pump comprising:
- a plurality of compression stages;
- a booster stage, wherein the plurality of compression stages and the booster stage comprise respective rotors supported for rotation on one or more common drive shafts;
- and
- a recirculation valve associated with the booster stage configured to cause selective recirculation of pumped fluid from an outlet of the booster stage to an inlet of the booster stage above a predetermined pressure.
1 more element
A stator for a multi-stage pump, wherein the stator comprises:
- an outer casing portion that forms respective pumping chambers of a plurality of compression stages and a booster stage and defines a booster inlet, a booster outlet, and a recirculation channel that extends through the outer casing portion between the booster outlet and the booster inlet;
- and
- inter-stage walls for forming partitions between the respective pumping chamber.
Dependencies are inferred from the claim text.