PURPOSE: To eliminate an outlet adjusting valve at a water supplying pump driven by a turbine and enable a construction cost to be reduced by a method wherein a communication pipe and a water supplying stop valve are arranged between a pipe after a check value of the water supplying pump driven by a turbine and a pipe after another check valve of the water supplying pump driven by a motor and the water supplying stopper valve is arranged in a pipe after the check valve for the water supplying pump driven by the motor.
CONSTITUTION: There is added a water supplying stopper valve 14 fixed on a connecting pipe for connecting a pipe after a check valve for a water supplying pump driven by a turbine (T-BFP) with another pipe 13 for connecting the pipe after a check valve for a water supplying pump driven by a motor (M-BFP). In the case that T-BFP 7 is used when a plant is start a water supplying stopper valve 15 after a check valve 3 of M-BFP is fully closed so as to cut M-BFP 2. In addition, the water supplying stopper valve 14 and an outlet valve 5 of M-BFP are fully closed and T-BFP 7 is increased in its number of rotation up to a predetermined value, thereby a re-circulation operation of BFP is performed. Then, an outlet adjusting valve 4 for M-BFP is gradually opened to get a desired flow rate. In this way, an operation in the system can be carried out with the less-expensive communicating pipes and water supplying stopper valves to perform an economic operation.
KANBARA HIDEYASU
KUWANA MAMORU
MATSUSHITA TSUGIYOSHI
WATANABE YOSHIE
IKETANI SATORU
HITACHI ENG CO LTD
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