| 摘要 |
PURPOSE:To shorten the starting and the stopping times of a steam turbine by avoiding the increase in thickness of the wall of a casing resulted by the increase of its capacity, and by reducing the thermal stress, by weld-bonding the outer casing of a high and intermediate pressure opposed type turbine, using forged steel and rolled sheet. CONSTITUTION:A main steam inlet 2 and a reheated steam inlet 3 are formed of forged steel, and shell parts 4 and 5 of the outer casing are formed of rolled sheet, and the main steam inlet 2 and the reheated steam inlet 3 are weld-bonded to a shell part 4. The distance between bearings accompanying large increase of the capacity of a casing can be shortened by making the sectional form of a reheated steam inlet 3 oblong and setting its minor diameter to the axial direction. With such an arrangement, the increase in thickness of a casing by the increase of its capacity can be avoided, and the thermal stress is reduced, so that the starting and the stopping times of a steam turbine can be shortened, thus operability of the turbine can be improved. |
