| 摘要 |
PURPOSE:To restrain vibration of a rotor, by providing such an arrangement that the gap between a packing body and the outer peripheral surface of the rotor is wider along the lower half section of the rotor than the upper half section thereof. CONSTITUTION:A packing body 10 and a rotor are arranged such that the gap between the packing body and the outer peripheral surface of the rotor is wider along the lower half section of the rotor than along the upper half section of thereof. The length of a fin 11 projected from the inner surface of the paking body is set to be longer along the lower half section of the rotor 1 than along the upper half section of the rotor 1 so that the gap S between the rotor 1 and the fin 11 is made to be constant. The circumferential pressure distribution of steam flowing into the fin 11 is such that the pressure of steam along the upper half section of the rotor 1 is higher than that along the lower half section of the rotor 1, and therefore, the rotor 1 is always pressed down. With this arrangement, it is possible to restrain vibration of the rotor 1.
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