Centrifugal pump impeller

Abstract

An impeller include a substantially cylindrical impeller body with an internal flow path connecting between an inlet opening through a first end surface and an outlet opening through a circumferential surface; and a balance weight embedded in the impeller body. The balance weight has a vertically-elongated shape in which its height in a cylindrical axis direction is larger than its thickness in a radial direction. The vertically-elongated balance weight is embedded in a circumferential section of the cylindrical impeller body.

1 . A centrifugal pump impeller, comprising:
 an impeller body having a substantially cylindrical shape with first and second end surfaces facing each other in a cylindrical axis direction, and with a circumferential surface interposed between the first and second end surfaces, and including an internal flow path which connects between an inlet opening through the first end surface and an outlet opening through the circumferential surface; and   a balance weight embedded in the impeller body,   wherein the balance weight has a vertically-elongated shape in which its height in the cylindrical axis direction is larger than its thickness in a radial direction, and the vertically-elongated balance weight is embedded in a circumferential section of the cylindrical impeller body.   
     
     
         2 . The centrifugal pump impeller of  claim 1 , wherein
 one end section of the impeller body serves as a relatively-thin wear ring section provided so as to surround the inlet; and   the balance weight is embedded in the wear ring section.   
     
     
         3 . The centrifugal pump impeller of  claim 2 , wherein
 a lower end surface of the balance weight embedded in the wear ring section is exposed in the first end surface of the impeller body, and a though-hole passing through the balance weight in a thickness direction or a notch recessed in the lower end surface is formed in the balance weight; and   the impeller body includes a retaining section of the balance weight, which is formed by filling the through-hole or the notch of the balance weight with resin when forming the impeller body by molding.   
     
     
         4 . The centrifugal pump impeller of  claim 1 , wherein
 a plurality of positioning holes are formed in the balance weight; and   a positioning pin for positioning the balance weight in a predetermined section inside a mold when forming the impeller body by molding is inserted into each of the positioning holes.