| 摘要 |
PURPOSE:To eliminate a flow switch by executing the speed control when the quantity of water consumed is high while executing the constant speed control when said quantity is low and stopping a pump through the delivery pressure rise. CONSTITUTION:When the quantity of water consumed is high, a pressure detection signal is compared with a setting pressure by means of a first comparison means 3 which provides a signal to a speed control means 4 so as to execute the speed control. When the quantity of water consumed drops, a timer 6 functions if the output level of the speed control means 4 is lower than a setting level, and a switch 9 is switched upon elapse of predetermined time so as to execute the constant speed operation of pump based upon a constant signal produced from a constant speed generator 8. Consequently, pressure control can be executed without requiring a flow switch.
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