To reduce the total weight of a bucket by maximum about 30% by a hybrid bucket, to reduce the mounting stress and to enhance the reliability without changing any aerodynamic characteristic of a blade-shaped portion.
A steam turbine rotor wheel includes a plurality of buckets (10 and 34), each of which has a shank portion (12) and a blade-shaped portion (14) and is fixed around a circumferential part of the wheel, and a plurality of buckets include two groups of buckets (10 and 34) having predetermined resonance frequencies different from each other. A method for reducing the vibration in the bucket row on the steam turbine rotor wheel includes (a) a step of preparing the bucket (10) of the first group having the first predetermined natural frequency range, (b) a step of preparing the bucket (34) of the second group having the second predetermined natural frequency range different from the first predetermined natural frequency range, and (c) a step of assembling the bucket out of the buckets in the first and second groups on the rotor wheel in an alternate manner.
| US4097192A | 1978-06-27 | |||
| US6042338A | 2000-03-28 | |||
| US5931641A | 1999-08-03 |
Hirokazu Ogura
Nobukazu Ito
Toshihisa Kurokawa
Next Patent: TEMPERATURE CONTROL OF EXHAUST SYSTEM