| 摘要 |
PURPOSE:To withstand the increased temperature and increased pressure of main steam requirements by forming a high pressure outside casing in a barrel-type structure divided in two in the axial direction and with no horizontal flange in the high pressure section of a high powered steam turbine. CONSTITUTION:Double discharge type nozzle boxes 4c, 4d are arranged at both ends of a high pressure stage group. High pressure outside casing 2a, 2b have no flange and are formed in a barrel-type structure divided in two in the axial direction. The steam passing a nozzle 4b and blade 5b flows between the outside casings 2b, 2a and an inside casing 3, and mixing with the steam flown out of the first high pressure blade 5a, then flows into the second high pressure nozzle. Therefore, the high pressure inside casing 3 is invariably kept at a higher pressure at its outside, thus its strength design is made very easy. Accordingly, the steam turbine can withstand an increase of main steam requirements, and the operability can be improved. |
