| 摘要 |
PROBLEM TO BE SOLVED: To improve an impeller of pump so that a centrifugal pump can be used with a capacity bigger than that of optimal operation reference point, and without a risk damaging a shaft seal device or the like. SOLUTION: The centrifugal pump, comprising a pump volute 2, a rear wall 4 of the pump, a shroud 22, and an impeller 20 having a balance hole extending through the shroud, has the impeller attached to a pump shaft 6 and rotates inside the volute. In an arrangement of the balance hole 26 passing through the shroud 22, an opening 30 of the hole 26 located in front of the impeller shroud 22 is located ahead of an opening 32 positioning in a back face of the impeller shroud 22, and located, in rotating direction, nearer to a shaft 8 of the pump than the opening 32 of the back face of the impeller shroud 22. COPYRIGHT: (C)2007,JPO&INPIT
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