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:
Sep. 24, 1991
Filed:
Dec. 05, 1989
Kiyoshi Yanagisawa, Kanagawa, JP;
Mitsuru Maeda, Kanagawa, JP;
Yoshiyuki Maruta, Kanagawa, JP;
Toshitsugu Sase, Kanagawa, JP;
Ebara Corporation, Tokyo, JP;
Abstract
The present invention is drawn to a screw compressor having a wide operating range with respect to flow rate and pressure ratio, wherein a discharge opening portion of a casing is provided with a generally tapered notch portion so that compressed gas is gradually discharged from a certain fixed point where a volume ratio of one groove defined by rotors and the casing is smaller than an inherent built-in volume ratio. Since the present invention is arranged in the above-mentioned manner, the flow of the gas at the discharge opening portion is reduced by the notch portion which is readily formed. Thereby the variation range of the pressure (the amplitude of pulsation of the pressure) is decreased and the noise level is lowered. Further, a loss of pressure resulting from the rapid flow of the gas is restricted to thereby widen a range of preferable performance of the compressor.