| 摘要 |
PROBLEM TO BE SOLVED: To provide a butterfly type steam valve of low cost that is usable even in high-temperature main steam or re-heating steam temperature conditions roughly over 600°C. SOLUTION: This device is provided with a valve box 26 connected to a steam pipe at a steam inlet part of a turbine main body, and integrally installed with the turbine main body, a valve rod 28 supported by a bearing 29 of the valve box 26, and having a through hole 30 for supply of cooling steam at an axial direction center part, and a valve element 27 that is opened and closed as the valve rod is rotated. To the through hole 30 in the valve rod 28, cooling steam of the turbine main body, extract steam introduced from a turbine extract line, or steam introduced from other system line is supplied to be cooled. As material of the valve box 26, the valve rod 28, or the valve element 27, ferrite-based heat-resistant steel is used. Preferably, austenite-based heat-resistant steel or Ni-based heat-resistant steel is used. COPYRIGHT: (C)2005,JPO&NCIPI
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