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US 6,776,588 B1Granted
Dry compressing vacuum pump having a gas ballast device
AssigneeLeybold Vakuum GmbH
InventorsLutz Arndt, Thomas Dreifert, Michael Hölzemer, Jürgen Meyer, Frank Schönborn
Life of this patent
Estimating the term…
Abstract
A dry compressing vacuum pump (1) has a continuous or graduated inner compression. A gas ballast device (8) selectively adds a ballast gas to a pumped gas. The gas ballast device has an isolating valve (11), a non-return valve (12) which prevents the escape of gases from the pump through the gas ballast device to the outside, and a pressure differential valve (13).
Claims8
A dry compressing vacuum pump comprising:
- a continuous or graduated inner compression chamber;
- pumping element movably disposed in the compression chamber;
- a gas ballast device connected with the chamber and having connected in series:
- (1) an isolating valve;
- (2) a non-return valve preventing the escape of gases from the pump through the gas ballast device to the outside;
- and
- a differential pressure valve which attains its open position only when a difference between atmospheric pressure and a pressure present at the differential pressure valve on the pump side exceeds 500 mbar.
4 more elements
A multi-state vacuum pump comprising:
- a plurality of compression chambers interconnected to define a plurality of pumping stages;
- a pumping element movably mounted in each chamber;
- a gas ballast device having:
- an interconnected isolating valve and a non-return valve connected with one of the stages to prevent the escape of gases from the pump through the gas ballast device to the outside, and
- a differential pressure valve configured to open at a pressure difference of 500 to 1000 mbar to admit gas from the outside to pass through the gas ballast device into the one stage.
2 more elements
A compressing vacuum pump comprising:
- a plurality of compression stages with progressively higher compression from a first stage to a last stage;
- a gas ballast which selectively supplies a ballast gas to one of the stages after the first stage and before the last stage, the gas ballast including:
- a one-way valve and a pressure differential valve which permit the ballast gas to enter the one-stage when pressure in the one stage is below a pressure of the ballast gas by a 500-1000 mbar pressure differential and which block gases from leaving the one stage.
Dependencies are inferred from the claim text.