| 摘要 |
PROBLEM TO BE SOLVED: To obtain a device for controlling the movement of a packing ring/ segment between a rotary member and a stationary member of a steam turbine or the like between the position of a large clearance at the starting time and the position of a small clearance position at the constant operation time. SOLUTION: A variable clearance packing ring includes a plurality of segments extending in the circumferential direction which is disposed in a dovetail slot provided in the stationary member, a circular arc form of seal surface facing a rotor, and a flange extending in the axial direction in the dovetail slot. A pin is protruded in the axial direction from both the sides of the stationary member in the position between the flange of the segment and the seal surface. A centering ring 50 is mounted to the pin, and the thermal expansion coefficient of the ring is larger than that of the segment. The centering ring is engaged with the flange of the segment at a first position and is engaged with the flange at a second position in response to the relative thermal expansion of the segment and centering ring, and the biasing force of the spring inwardly moves the segment in the radial direction.
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