For reducing leakage loss, the steam turbine rotor is generally a shaft of a small diameter with narrow clearances, so its operating speed is usually higher than the critical speed. For this reason, the turbine rotor shaft is liable to rub against seal fins in cases in which the casing is humped or the rotor is bent due to the temperature difference between top and bottom, which causes bending of the shaft and subsequent large vibrations, which may grow to a violent level if they take place at a critical speed. Rub check is considered to be an effective practice to prevent this rubbing vibration, and an instrument, named Rub-check Monitor, has been developed for this purpose. It enables rub check by remote control from the central control room. The sound transfered through the gland causing was measured and analyzed in several steam turbines under different conditions, during rubbing and during absence of rubbing. The shaft rubbing vibration was calculated by digital simulation and the results indicate the importance of rub check before increasing the turbine speed to a critical speed.

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  • Corporate Authors:

    Mitsubishi Heavy Industries Limited

    5-1 Marunouchi, 2-chome, Chiyoda-Ku
    Tokyo 100,   Japan 
  • Authors:
    • FUKUDA, S
    • Tsushima, T
    • Shimosakoda, A
  • Publication Date: 1974-10

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Filing Info

  • Accession Number: 00080061
  • Record Type: Publication
  • Source Agency: Mitsubishi Heavy Industries Limited
  • Report/Paper Numbers: Series No. 31
  • Files: TRIS
  • Created Date: May 1 1975 12:00AM