| 摘要 |
PROBLEM TO BE SOLVED: To protect a narrow part and sliding part by setting the axial cross section of each seal ring to an asymmetric shape of a labyrinth block having a projection in the high pressure side. SOLUTION: A rotor 1 has a seal ring receiver 7 in its circumference and the seal ring receiver 7 supports a movable seal ring 8 embedding a sealed fin 5 extended toward the circumference of the rotor 1. A steam pressure acting face 10 is provided in the outer circumference of the movable seal ring 8 in a space toward a seal ring retreat face, communicated with a plurality of bypass holes in the circumferential direction, and reaches the outer circumference of the rotor 1 from the bypass holes via a clearance between the circumference of the movable seal ring 8 itself and the seal ring receiver 7. The internal circumferential side of the movable seal ring 8 opposite to the steam pressure acting face 10 has the sealed fin 5 embedded as a labyrinth block, however, has a projection formed in the high pressure side, has no projection formed in the low-pressure side, and is constituted into a asymmetrical shape completed in a position corresponding to a thrust receiver face 11.
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