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. 20, 1991
Filed:
Jun. 01, 1990
Applicant:
Inventors:
Jean-Marie Crinquette, Annecy le Vieux, FR;
Jacques Long, Annecy, FR;
Assignee:
Alcatel Cit, Paris, FR;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F04B / ; F04B / ; F04B / ; F01C / ;
U.S. Cl.
CPC ...
417205 ; 417251 ; 417310 ; 418 83 ; 415 90 ;
Abstract
A two stage dry primary pump comprises, in a single common stator: a screw pump at its low pressure end; and a fluid viscous effect, single rotary screw gas exhaust pump at its high pressure end; with a link duct providing communication between the screw pump and the viscous effect, single rotary screw gas exhaust pump. The invention is applicable to vacuum pumps.