| 摘要 |
PROBLEM TO BE SOLVED: To prevent the flowing of a solid material into a cooling tube of a condenser by cleaning a filter when circulating water pumps are started by a cleaning drive means for cleaning the filter when a differential pressure between a front side and a rear side of the filter exceeds a predetermined value. SOLUTION: Start signals of circulating water pumps 1a, 1b are input to an OR circuit 22A. The signals of the pumps 1a, 1b are held by a self-holding circuit constituted of a timer 23A and a wipe-out circuit 24A for a predetermined time set by the timer 23A. The timer 23A is an on-delay timer operating after a predetermined time is elapsed, and self-holding of the self-holding circuit is released by the start signal of the timer 23A. The signals of the self-held pumps 1a, 1b are input to the circuit 23B, and output as a cleaning drive command to a filter through the circuit 24B.
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