| 摘要 |
PURPOSE:To prevent the overloading of a pump by increasing the resistance of a flow path on a water chamber side for perfomring back washing to a given value during the period from the beginning of switching a switch valve in the flow path to the direction of back washing to the ending of the switching operation. CONSTITUTION:The flow paths of cooling water to the water chambers 7 and 8 of a condenser are each switched toward the direction of back washing orderly by four-way back washing valves 5 and 6 provided to the flow paths of cooling water from a pump 1. In this case, the four-way back washing valves 5 and 6 of the water chambers 7 and 8 to be back-washed selectively are switched orderly toward the direction of back washing, and at the same time throttle valves 9 and 13 or 10 and 14 provided in the flow path on the water chamber to be back- washed are operated to increase the resistance of the corresponding flow path above that of the water chamber. |
