| 摘要 |
PURPOSE:To improve minimum flow operation of a multi-stage pump, by providing a cooler at a portion of a balance pipe. CONSTITUTION:Water carried from a balance chamber 6 through a balance pipe 8 is cooled by a cooler 15 and then introduced into a suction chamber 5. Thus, since water cooled by the cooler 15 is supplied to the suction chamber 5 via the balance pipe 8, temperature of water drawn into a first-stage runner 3 from the suction chamber 5 is lowered to theutmost. Therefore, if a pump 1 is operated with a minimum flow, the temperature of pumped-up water is not raised abruptly and generation of cavitation due to the temperature rise can be minimized. Here, it is to be noted that the cooler 15 can be of any type if it can cool water recirculated from the balance pipe 8 to the suction chamber 5. |
