| 摘要 |
PURPOSE:To prevent a serious accident with a hydraulic driver for a main steam stop valve, by providing a limit switch which performs action below the overtravel at the time of entire closure, to detect the rupture of the valve spindle in testing and after starting. CONSTITUTION:When a solenoid valve 12a is energized, compressed air is introduced into the upper part of a cylinder 12c to push a pilot valve 12d down. At that time, control oil 10 flows from a port 10b to another 10a and is released out of the cylinder 12c to entirely close an accessory valve 1 and a main valve 1. As a result, an entire closure indication limit switch 21 performs action if a valve spindle 3 is normal. If the valve spindle 3 is ruptured, an oil cylinder descends below an entire closre position A and the valve spindle rupture indication limit switch 21 performs action. According to this constitution, the abnormality of the valve spindle 3 is detected from the fact that the limit switch 21 is acting in the testing of operation of before the starting of a turbine. |
