| 摘要 |
PURPOSE:To prevent the condensation of steam flowing into the keyway parts of wheels so as prevent effectively stress corrosion cracking, by communicating the clearances between wheels on the upstream side with an exhaust chamber on the downstream side by means of communication passages provided on a rotor. CONSTITUTION:Plural number of wheels 12 each of which is provided with blades 11 on its periphery are shrink-fitted on a rotor 13 via fit drive keys 14 respectively. In this case, a clearance is provided between bore parts 15 of neighboring wheels 12, and outside space of each bore part 15 is communicated with an exhaust chamber 17 at the downstream of low-pressure stage wheel through the said clearance and a communication passage 16 formed in the rotor 13. And the communication passage 16 comprises a center hole 16a piercing through the center part of the rotor 13 along the axis and openings 16b and 16c piercing in the radial direction of rotor which communicate the center hole 16a with the clearance between bore parts 15 and with the exhaust chamber 17 respectively. Thus, the condensation of steam can be prevented because of the lowered saturated steam temperature caused by the reduced pressure at each bore part 15. |
