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:
Feb. 26, 1991
Filed:
Nov. 20, 1989
Applicant:
Inventor:
Noboru Tsuboi, Kakogawa, JP;
Assignee:
Kabushiki Kaisha Kobe Seiko Sho, Kobe, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F04C / ; F04C / ; F04C / ;
U.S. Cl.
CPC ...
418 84 ; 4182011 ; 418D / ; 418 87 ;
Abstract
A screw vacuum pump which includes a pair of screw rotors meshing each other with a small gap defined therebetween. A closing valve is provided in an oil circulation line leading from an oil stripper to a rotor chamber accommodating the screw rotors. A pressure switch for detecting a suction pressure is connected to the closing valve. When the suction pressure is lower than a predetermined value (i.e., at high level of vacuum), the closing valve is opened to supply the oil into the rotor chamber.