| 摘要 |
PURPOSE:To improve the performance and the efficiency of a steam turbine without any increase in thickness of the inlet part of main steam and in size of the turbine by displacing the center point of the internal radius of the inner casing which contains a nozzle box from the center point of the external radius of the chest part of the nozzle box. CONSTITUTION:An inner casing 4 is disposed inside an external casing 5 and communicated therewith by a straight pipe part 26 and a sleeve pipe 7. A nozzle box 8 is disposed inside the inner casing 4 and the lower end part of the sleeve pipe 7 is engaged with inlet part 31 of the casing 4. There is provided a distance 29 between the center point 27 of the external radius of the chest part 15 of the nozzle box 8 and the center point 28 of the internal radius 14 of the inner casing 4. Consequently, the external radius of the chest part 15 may be reduced and the cracking pressure of the flange 18 be also reduced, thereby reducing the height of the horizontal flange 18 without need of gaining the thickness of the inner casing. Additionally, the size of the horizontal flange bolt 19, the length of the internal radius 30 of the external casing, the thickness of the external casing, the size of the horizontal flange 24 of the external casing and the size of the horizontal flange bolt 25 thereof may be reduced, whereby making the main steam inlet compact. |
