| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a countermeasure technology against some defects found in a device in which an operation and a stopping of a submerged pump are carried out under application of the conventional water level sensor so as to control a water level in a discharge water reservoir, the water level sensor is frequently troubled due to discharging of water and the water level control cannot be performed.SOLUTION: The conventional water level sensor is eliminated and in place of it, an idling operation sensor 12d is used. When the idling operation sensor 12d detects an idling operation signal, a control unit 12b immediately stops a submerged pump 12c. After that, the control unit 12b energizes the submerged pump 12c. This stopping and re-energization are repeated to control a water level 13a in a discharged water reservoir within a pre-set range. The re-energization is carried out at a specified period (a mode A), after specified time after stopping (a mode B), and after a time corresponding to an operation time of the submerged pump 12c after stopping (a mode C) and the like.</p> |
