Seal ring for steam turbine

Abstract

Seal ring provided between rotating portion and fixed portion in rotating machine of steam turbine and the like is improved to carry out predetermined movement accurately so as not to cause deterioration of sealing performance. Seal ring is split into upper, lower, right side and left side seal ring pieces 1a, 1b, 1c, 1d, contacting slidably with each other via split planes 3a, 3b, 3c, 3d with spaces 9a, 9b, 9c, 9d being formed in the respective split planes. Springs 4a, 4b, 4c, 4d are interposed in the spaces 9a to 9d for activation in upward and downward directions. The upper and lower seal ring pieces 1a, 1b are engaged with seal ring guides 5a, 5b and 6a, 6b and the right side and left side seal ring pieces 1c, 1d are engaged with seal ring guides 7, 8 so that all of the seal ring pieces 1a to 1d are slidable in the upward and downward directions. Further, on the respective tips of the seal ring guides 5a, 5b and 6a, 6b, spaces 10a, 10b of the upper seal ring piece 1a and spaces 10c, 10d of the lower seal ring piece 1b are formed and springs 11a, 11b, 11e, 11d are provided in the spaces 10a to 10d for activation in the upward and downward directions. The respective seal ring pieces are prevented from skirmishing with each other and the upper and lower seal ring pieces move toward the inner side at the time of load so as to make narrower the clearances between seal fins 2a, 2b and corresponding rotor surface.

Description

technical field [0001] The present invention relates to a seal ring used between rotating parts of a rotating machine such as a steam turbine. technical background [0002] In rotary machines such as steam turbines, for example, between the rotating peripheral surface divided by the front end of the moving blade and the blade holding ring, or between the inner peripheral front end of the stationary blade and the rotor surface opposite to it, in order to align the rotating part with it. A sealing comb is provided for sealing between the opposite fixing parts, and a sealing ring is provided to support the sealing comb. [0003] image 3 is a schematic diagram of a representative seal ring available at image 3 In the circumferential direction, the split pieces 21a, 21b, 21c, and 21d divided into four pieces of upper, lower, left and right are arranged, and the split pieces 21c of the left and right seal rings are arranged in the horizontal direction with the supporting parts 2...

AI Technical Summary

Problems solved by technology

Therefore, the urging direction of the spring 22 is inconsistent with the moving direction, and the end faces of the adjacent split pieces 21a, 21b, 21c, and 21d are separated from each other on the prescribed moving locus, and engaged abnormally, resulting in the so-called mutual interference phenomenon of the split pieces. Tablets may be stuck (occurrence of biting phenomenon)

[0005] Moreover, if such a stuck phenomenon occurs, the gap between the rotor and the rotating body will increase, causing air leakage, and there is a disadvantage that the sealing performance will be lowered.

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