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:
Mar. 04, 2008
Filed:
Jul. 06, 2005
Shusaku Nabesaka, Tokyo, JP;
Sadashi Tanaka, Tokyo, JP;
Shinsuke Sakurai, Tokyo, JP;
Hitachi Industries Co., Ltd., Tokyo, JP;
Abstract
A turbo-type fluid machine comprises a mouth ring part provided between a shroud of an impeller and a pump casing and having a seal function. The mouth ring part comprises an impeller ring on a side of the shroud of the impeller and a casing ring provided on a side of a non-rotating body wall surface of the casing. The impeller ring is structured to have a stepped portion that is in the form of a staircase with at least two steps to be small in diameter toward a suction side of the impeller and large in diameter toward an outlet of the impeller. The casing ring is labyrinth-shaped to comprise a projection and a recess. A narrow clearance part having a narrow radial clearance is formed between the projection and the impeller ring. A flow passage spatial portion defining an enlarged portion of the narrow radial clearance is formed by the recess and the stepped portion of the impeller ring.