| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a pump controller for a direct feed water supplying system of a large rate of flow controlled by a presumptive terminate pressure constant control capable of preventing a pump from cavitation even in the large rate-of-flow water supplying operation in which the main pipe pressure has lowered to the prescribed minimum value or a level near it and provide a method therefor. Ž<P>SOLUTION: The pump controller is designed so as to lower the loss of check valves for counterflow prevention and embodied in a parallel arrangement of check valves selected so that the dispersion in the loss characteristics of the check valves lessens. Even when one of the check valves goes in failure, or one of them is removed temporarily for maintenance, the constitution allows continuing the parallel water supplying operation with the remaining check valves by limiting the inverter frequency to a value corresponding to the limit rate of flow suppliable. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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