| 摘要 |
PURPOSE:To stably control pressure by obtaining the control width for the number of revolution in order to obtain the same operation point before and after the increase and the reduction of the number of units in a variable-speed pump group from the characteristic curve of the pump and outputting the number-of-revolution control width, corresponding to the resistance characteristic of a discharge valve. CONSTITUTION:A pressure gauge 5 and a flow-rate meter 6 are installed through a discharge valve 3 into the water distribution conduit 4 of a variable-speed pump 2, and a sequence controler 7 controls the linkage operation of a motor and the discharge valve 3. An automatic pump controller 9 controls the number of units and pressure on the basis of the number of revolution, opening degree of the valve, pressure, and the flow rate. In order to obtain the same operation point before and after the increase and the reduction of the number of units, the control width for the number of revolution is obtained according to the characteristic curve of the pump, flow rate, and the number of revolution, by a number-of-revolution adjusting width calculating apparatus 14 and outputted from a number-of-revolution adjusting width output apparatus 15, corresponding to the resistance characteristic of the discharge valve. Therefore, the sharp variation of pressure in the case when the number of units increases or reduces can be prevented.
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