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:
Jan. 02, 2001
Filed:
Feb. 05, 1999
Applicant:
Inventors:
Assignee:
Leybold Vakuum GmbH, Cologne, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F01D 1/36 ;
U.S. Cl.
CPC ...
F01D 1/36 ;
Abstract
The present invention relates to a friction vacuum pump having at least one turbomolecular pump stage (,) joined at its pressure side to a screw pump stage (,). In order to improve the pump properties it is proposed that a filling stage (,) be arranged between the turbomolecular pump stage (,) and the screw pump stage (,) that has blades (,) whose length corresponds at the suction side to the active length of the blades at the pressure side of the turbomolecular pump stage (,), and at the pressure side to the depth of the suction-side region of the screw (,) of the screw stage (,).