STEAM INCREASE/DECREASE VALVE DRIVER FOR STEAM TURBINE

PURPOSE:In a device for controlling a steam increase/decrease valve through operation of a hydraulic cylinder, to enable abrupt stoppage of said valve by providing a bypath line which detours the controller for a hydraulic cylinder and extracts the pressurized oil quickly upon breaking of load. CONSTITUTION:A servo valve 19 is controlled to feed pressurized oil from an oil pressure source OS through a line II into a hydraulic cylinder 21 to roll a lever 22 thus to function regulating valves 25, 28 for upper and lower steam through levers 23, 26 and cams 24, 27. In such device, a bypath line I including a line I b for draining the pressurized feed line I a to said cylinder 21 and the lower section of said cylinder 21 is provided. Said bypath line I will detour the servo valve 19 while an exchange valve 23 and check valve 35 are placed in the line I . The exchange valve 33 will function upon breaking of load to close the steam regulating valves 25, 28 quickly.