Title:
CENTRIFUGAL FLUID MACHINERY
Document Type and Number:
Japanese Patent JP3497962
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To improve unstable characteristics caused by reduction of all pump head in a low flow rate region by forming a blade outlet diameter of a spurn water blade smaller than a stage push outer diameter arranged on a sliding part between a stage and a main shaft.
SOLUTION: In centrifugal fluid machinery, the entrifugal force by turning at an inlet part of an impeller 3 generates flow from a core plate side in a radial direction, and reverse flow is generated in the vicinity of an inlet side plate of the impeller 3. When the reverse flow is invaded into a return flow passage 7, pre-turning component is enlarged in an equation of a theoretical pump head, and thereby, a unstable characteristic of a pump head characteristic is generated as well as reducing the all pump head. The outlet diameter &phiv D of a spurn water blade 6 is formed smaller than an outer diameter &phiv D' of a stage bush 8. When it is suppressed that flow in a return flow passage 7 is influenced by reverse flow of a low flow rate region, reduction of the all pump head is eliminated, and the stable characteristic is obtained.
Inventors:
Yuji Nagai
Yoshiharu Ueyama
Yoshiharu Ueyama
Application Number:
JP33335296A
Publication Date:
February 16, 2004
Filing Date:
December 13, 1996
Export Citation:
Assignee:
Hitachi Industries Co., Ltd.
International Classes:
F04D1/08; F04D29/44; (IPC1-7): F04D29/44; F04D1/08
Domestic Patent References:
| JP6249200A | ||||
| JP3138497A | ||||
| JP633891A | ||||
| JP1318790A | ||||
| JP6019985A |
Attorney, Agent or Firm:
Yasuo Sakuta
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