| 摘要 |
PURPOSE:To reduce the quantity of steam per unit life of an intercept valve and increase the stability upon starting the turbine by using an assembled reheating steam check valve incorporating a bypass small valve in a main valve, as a reheating stream check valve. CONSTITUTION:The assembled reheating steam tight valve 21 is interposed at the intermediate part of a high-pressure reheating pipe causing steam to flow out toward a middle pressure turbine, and a valve box 22 contains therein an intercept valve 23, a main valve 24 and a bypass small valve 25. Upon starting the turbine, the bypass small valve 25 is first raised by a suitable driving source, and a point (the valve 25 fully open) where the head part of the small valve 25 makes contact with the shoulder part 24b of the main valve 24, is detected by a differential transformer 23. By this detection signal, an open signal to a reheating steam tight valve is locked and held, and valves 23 and 24 are fully closed and held. Thereafter, the intercepted surface 23 is gradually opened, and by the double throttling of the valves 23 and 25, the steam quantity 35 to the intermediate pressure turbine is controlled, and the turbine is raised to the rated rotational speed. |
