| 摘要 |
PURPOSE:To effectively prevent the deflection of a rotary main shaft near an impeller by supporting the upper end of the rotary main shaft with a ball bearing and supporting its lower end with a ball bearing provided on the boss section of a pump casing so that the rotary main shaft can be supported with its length made short. CONSTITUTION:The upper end of a rotary main shaft 4 is supported by a ball bearing as before. The lowermost impeller 8 is fitted to the lower stage of the rotary main shaft 4, and pump casings 10 of the uppermost and lowermost impellers 8 among multi-stage impellers 8 are provided with ball bearings 5C. The inner ring of this ball bearing 5C is directly and loosely coupled with the rotary main shaft 4 so as to facilitate the vertical movement, and its outer ring is firmly held by the boss section 35 of the pump casing 10. The impeller 8 is fitted with a rotary split sleeve 37 on its inner diameter side and is fixed at a predetermined gap (c) from the ball bearing 5C. Accordingly, the rotary main shaft 4 can be supported with its shaft length made short, and the deflection of the main shaft 4 can be effectively prevented.
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