| 摘要 |
PURPOSE:To enable various kinds of valves to be replaced safely, by providing such constitution as having the 1st and the 2nd stop valves closed completely so as to interrupt the supply of pressure oil to various kinds of said valves and loosening the 1st and the 2nd plugs in order to enable the sealing condition of each stop valve to be ensured, during the operation of a steam turbine. CONSTITUTION:A hydraulic valve is replaced by removing a stopper block 24, closing the 1st stop valve 20, and then closing the 2nd stop valve 21. In this case, the 2nd handle 21a is located in an upper position and the 1st handle 20a is located in a lower position, respectively, and therefore no reverse operation is possible. Closing the stop valve 21 of an emergency oil line 16, at first, may cause a disk dump valve 8 to open, resulting in a possible danger of a large amount of control-oil drain, if there are failures in a cutoff valve 11 and a servo valve 7. However, this danger can be avoided surely. The aforesaid operations are followed by the loosening of the 1st and the 2nd plugs 23, 28 so that the complete sealing of each of stop valves 20, 21 may be ensured. Then, the stopper block 24 is attached to the handle 21a of the 2nd stop valve 21 to prevent its looseness.
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