To provide a water feed pump device suppressed in an excessive/insufficient water amount stop and a pressure variation at restart.
In a water feed pump device, a variable speed control device has: upper limit target pressure on a piping resistance curve of a pump; a pump rotation speed (inverter frequency) for imparting the Q-H performance of the pump which satisfies the pressure; pump stop pressure which takes pressure keeping in consideration; a pump rotation speed (inverter frequency) at a stop which is defined by the stop pressure; and a control parameter with a lower limit value on the resistance curve as start pressure. Normally, upper limit target pressure on the resistance curve is set as an upper limit coordinate, and the stop pressure taking the pressure keeping in consideration is set as a lower limit coordinate. Prescribed pressure is constantly controlled on a line connecting the upper limit coordinate and the lower limit coordinate, a flow rate switch detects the excessive/insufficient water amount, the pump is stopped when a sufficient prescribed time has elapsed in this state for the suppression of a pump start frequency, and when the detected pressure reaches pump start pressure after the stop of the pump, the pump is restarted.
JPS5954797A | 1984-03-29 |