The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 17, 2004
Filed:
Jun. 17, 2002
Applicant:
Inventors:
Lutz Arndt, Troisdorf, DE;
Thomas Dreifert, Köln, DE;
Michael Hölzemer, Bergheim, DE;
Jürgen Meyer, Pulheim, DE;
Frank Schönborn, Köln, DE;
Assignee:
Leybold Vakuum GmbH, Cologne, DE;
Primary Examiner:
Int. Cl.
CPC ...
F04B 2/500 ;
U.S. Cl.
CPC ...
F04B 2/500 ;
Abstract
A dry compressing vacuum pump ( ) has a continuous or graduated inner compression. A gas ballast device ( ) selectively adds a ballast gas to a pumped gas. The gas ballast device has an isolating valve ( ), a non-return valve ( ) which prevents the escape of gases from the pump through the gas ballast device to the outside, and a pressure differential valve ( ).