| 摘要 |
PURPOSE:To enable quick operation of a steam valve without any increase in the capacity of a servo valve, by a method wherein an electromagnetic valve is mounted parallel to the servo valve which controls the oil in the actuator of the steam valve. CONSTITUTION:In a system which feeds and discharges control oil P0 to and from an actuator 26 for driving the main steam check valve and the like of a steam turbine, an electromagnetic valve 43 is located parallel to a servo valve 25. During usual control such as the start of the turbine, a deviation between an opening instruction signal A and an actual opening signal B is inputted in a coil 25a of the servo valve 25 through amplifiers 23 and 24 to control opening of a valve. When the opening instruction A is widely varied during testing of a valve, detectors 40a and 40b for detecting the current of the amplifier 24 are operated to close contacts 41a and 41b and interconnect the electromagnetic valve 43 and a power supply 42, the electromagnetic valve 43 is operated in the same direction as that of the servo valve, and a steam valve is controlled quickly through simultaneous control of feed and discharge of control oil to and from the actuator by means of both valves. |
