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. 26, 1980
Filed:
Oct. 20, 1978
Applicant:
Inventors:
Hidetomo Mori, Ebina, JP;
Shingo Ishizawa, Ebina, JP;
Assignee:
Hitachi, Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F04B / ; F04B / ; F04B / ;
U.S. Cl.
CPC ...
417295 ; 417302 ;
Abstract
In a compressor unit of a type wherein the ratio of delivery pressure relative to intake pressure, i.e., pressure ratio, is required to be as uniform as possible during unloaded and loaded operating conditions, as is in screw compressors of dry type, solenoids are used to drive an intake throttle valve and a pressure relief valve in such a manner that, when the throttle valve is closed, the pressure relief valve is opened to avoid an increase of the pressure ratio. When signals are produced to close the throttle valve and open the pressure relief valve, the solenoids are instantanously operative to close the throttle valve and open the pressure relief valve.