| 摘要 |
PROBLEM TO BE SOLVED: To carry out the changing over of two or more cooling systems through a simple device by providing a directional control valve which is actuated through pressure difference between two kinds of cooling fluids to change over the supply of the two kinds of cooling fluids to a high temperature section. SOLUTION: In the case where in a combined cycle gas turbine plant, cooled air from a compressor is used as cooling fluid for the gas turbine at the time of starting or just after starting the gas turbine, a directional control valve 50 is provided at a meeting place of a cooling pipe line and a cooling steam pipe line. The directional control valve 50 has a valve plug which moves right and left according to a difference between force (P1×S1 ) depending on the pressure P1 of cooling fluid A acting on a valve 52 (area S1 ) and force (P2×S2 ) depending on the pressure P2 of cooling fluid B acting on a valve 53 (area S2 ) to open and close an entrance for the cooling fluid. In the case of P1×S1 >P2×S2 an inlet 55 is communicated with an outlet 57, and an inlet 56 is shut off, and the cooling fluid A is sent through the outlet 57 to the required cooling spot of the high temperature parts of a burner and the turbine.
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