| 摘要 |
PURPOSE:To prevent increase of vibration and reduction in the durability of pump shafts, by connecting pump units in a multiplicity of stages, and obtaining a required total pump head by discharging a fluid introduced into the first-stage unit from the final-stage unit. CONSTITUTION:Pump units 11A-11C are stacked in three stages by connecting them together by the intermediary of head covers 18A, 18B fixed respectively to the units 11A, 11B. In case that the apparatus is designed for two-mode operation, for instance, at 100% capacity and 60% capacity, a pump head H1 for the 100%-capacity operation can be obtained by driving all of motors 15A-15C. In 60%-capacity operation, on the other hand, the pump head at the same flow rate of a fluid to be handled can be reduced from H1 to H2 by stopping operation of the motor 15B of an intermediate unit 11B. With such an arrangement, it is enabled to reduce vibration of the shafts and to prolong the service life of bearings. |
