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:
May. 26, 1987
Filed:
Apr. 24, 1986
Applicant:
Inventors:
Masahiro Mase, Tochigi, JP;
Takashi Nagaoka, Ibaraki, JP;
Yoshitsugu Tsutsumi, Ibaraki, JP;
Minoru Taniyama, Ibaraki, JP;
Makoto Terajima, Ibaraki, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F01D / ;
U.S. Cl.
CPC ...
415 90 ; 415143 ;
Abstract
A vacuum pump including a centrifugal compressor stage on the side of a suction opening and a circumferential flow compressor on the side of an exhaust opening. The centrifugal compressor pump works as a Siegbahn pump at a steady state, and works as a centrifugal compressor under a transient condition at the initial stage of the pump operation, thus obtaining a high pumping speed under the transient condition.