| 摘要 |
PROBLEM TO BE SOLVED: To provide a pump structure for reducing fluid exciting force acting on a casing and reducing vibration noise of a pump in the multistage diffuser pump having a multistage guide vane diffuser and a return vane flow path disposed in the casing with respect to a multistage impeller installed on a rotary shaft rotatably mounted in the casing. SOLUTION: The multistage diffuser pump has the multistage guide vane diffuser and the return vane flow path disposed in the casing with respect to the multistage impeller installed on the rotary shaft rotatably mounted in the casing. In the impeller having the combination of front and rear two stages using the same configuration and the same number of vanes, phases in the circumferential mounting positions of at least a set of impellers are staggered by 0.47 pitch or more but not exceeding 0.53 pitch between the front and rear impellers. With this arrangement, the fluid exciting force acting on the casing in an axial direction is reduced and vibration noise of the pump is reduced. COPYRIGHT: (C)2008,JPO&INPIT
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