Patent ID: 8864443

Claim:
A sealing device for a steam turbine which includes a rotating region formed by a rotor and a member constructed to rotate integrally with the rotor, and a fixed region formed by a casing containing the rotating region, and by a member fixed to the casing, the sealing device being built into the steam turbine, the sealing device comprising: sealing fins provided in both or either of the rotating region and the fixed region; and spacers provided on the rotating region or fixed region, both facing the sealing fins, the spacers each using a free-cutting metal; wherein the fixed region includes a movable region that moves in the axial direction of the rotor by a pressure action of steam circulating through the steam turbine, the movable region being further constructed to move when urged by urging means acting in a direction opposite to that of the pressure action of the steam; when the fixed region includes each sealing fin, the sealing fin is mounted on the movable region, and each of the sealing fins is disposed to move in an axial direction of the rotor with respect to the rotating region; when the fixed region includes each spacer, the spacer is mounted on the movable region, and each of the spacers is disposed to move in the axial direction of the rotor with respect to the rotating region; when the fixed region includes the sealing fins and the spacers, the sealing fins and the spacers included in the fixed region are mounted on the movable region, and the sealing fins and the spacers included in the fixed region are disposed to move in the axial direction of the rotor with respect to the rotating region; when a loading pressure that the steam applies to move the movable region in the axial direction of the rotor is smaller than an urging force that the urging means uses to urge the movable region in the opposite direction, the sealing fin and spacer that face each other are ready to come into contact with each other; and upon the loading pressure exceeding the urging force, the movable region moves to a position at which a clearance between the sealing fin and spacer that face each other reaches a preset value.