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:
Oct. 26, 1993
Filed:
Dec. 20, 1991
Ken-ichi Kajiwara, Tokyo, JP;
Ebara Corporation, Tokyo, JP;
Abstract
A multistage centrifugal pump has a plurality of series-connected interstage casings of pressed sheet metal housing respective impellers. Each of the interstage casings includes a cylindrical side wall for housing an impeller, a bottom wall joined to the cylindrical side wall and extending around an inlet for the impeller, and a return blade attached to the bottom wall remotely from the impeller. The bottom wall has a central region projecting conically or spherically radially inwardly toward the impeller by a distance corresponding to the extent to which the bottom wall is deformable under an interstage pressure difference. The deformation of the bottom wall that is developed under the pressure generated by the impeller is borne only by the casing body itself without affecting the welded spots, which are prevented from being ripped off under stresses that would otherwise concentrate on the welded spots.