| 摘要 |
PROBLEM TO BE SOLVED: To provide a multiple stage centrifugal pump of long life and easy assembly. SOLUTION: This pump is provided with a pump part having two impellers 16, 17 built therein in series, a pump case having a suction port and a delivery port of liquid arranged thereon, a motor part driving the pump part, a hollow delivery side projection part 24 and a hollow suction side projection part 26 having predetermined inner diameter and length at a center part of one of opposing sides of the impellers, a shaft passing through the delivery side projection part, the suction side projection part and the impellers and rotatably supporting the impellers, a plain bearing reducing sliding friction by introducing liquid in a gap with the shaft, a projecting fitting parts 24a, 26a having predetermined width and length provided on surfaces of the delivery side projection part and the suction side projection part, a connecting pipe 20 forming recessed fitting parts 25a, 25b fitting with the projecting fitting parts and rotating the two impellers as one unit with fitting the projecting fitting parts and the recessed fitting parts, and at least one recirculation hole 28 formed on the connecting pipe and communicating to an inside of the connecting pipe. COPYRIGHT: (C)2008,JPO&INPIT
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