| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a pump direct water supply system and a pump direct water supply method in which a flow relay installed in piping is eliminated. Ž<P>SOLUTION: The head coefficient and discharge coefficient of a pump using a flow relay operation point flow as the rated flow are measured. The head approximate quadratic expression of the pump applicable in the small flow operating range is obtained from the measured values. The flow-loss head characteristic of a check valve for reverse flow prevention placed on the pump push-in side are measured. A pre-measured loss head of the check valve is deducted from the actually measured push-in head to calculate the actual net push-in head. Utilizing the head approximate quadratic expression of the pump applicable in the small flow operating range, the square value of the flow at that time is estimated and calculated by the principle that the sum of the pump head and the net push-in head is equal to the frictional loss head of the pump. By the square root of the value, the flow is calculated and estimated. The pre-set small flow detection set value is compared with the calculated flow to detect that the pump flow is equal to or lower than the set flow. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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