STEAM EXTRACTION EQUIPMENT FOR STEAM TURBINE

PURPOSE:To enhance the internal efficiency of a steam turbine and enlarge the steam extraction control range by providing a plurality of steam extraction adjusting valves and performing steam extraction by suitably switching each adjusting valve, thereby reducing pressure loss caused by throttling the adjusting. valve. CONSTITUTION:Two steam extraction passages 7 and 8 are arranged in parallel, rang ing from the high pressure side to the low pressure side of a steam turbine 1, and the end of each of which is connected to a header 9, The steam extraction passages 7 and 8 are provided with steam extraction adjusting valves 10 and 11 respectively interposed therein, while check valves 12 and 13 are interposed downstream therefrom. When the steam turbine 1 is run under a low load, if extracted steam pressure at a measuring point 14 on the high pressure side is equal to or higher than the header pressure and moreover the extracted steam pressure at a measuring point 15 on the low pressure side is lower than the header pressure, the steam extraction adjusting valve 11 is closed while the steam extraction adjusting valve 10 is opened, thereby extracting the steam having the set pressure from the header 9. When the extracted steam pressure at the measuring point 15 becomes higher than the header pressure, the steam extraction adjusting valve 10 is closed while the steam extraction adjusting valve 11 is opened.