A sealing structure in which free-cutting spacers on a sealing base plate and sealing fins on a rotor are opposed to each other is provided. The sealing base plate is disposed so as to be movable in an axial direction of the rotor. When a steam turbine increases in load, a pressure head moves in an
A sealing structure in which free-cutting spacers on a sealing base plate and sealing fins on a rotor are opposed to each other is provided. The sealing base plate is disposed so as to be movable in an axial direction of the rotor. When a steam turbine increases in load, a pressure head moves in an axial steam-pressure loading direction of the rotor and the sealing base plate connected to the pressure head moves in the axial steam-pressure loading direction. Since the free-cutting spacers at positions opposed to those of the sealing fins existing after the movement of the sealing base plate are maintained in a non-contact state, clearances between the sealing fins and the free-cutting spacers are dimensionally minimized.
대표청구항▼
1. 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
1. 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; andspacers 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; andupon 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. 2. The sealing device for the steam turbine according to claim 1, wherein: the movable region includes a sealing base plate to which the sealing fin or the spacer is fixed, a pressure head to which the sealing base plate is fixed and which receives the loading pressure of the steam, and a guide provided on the pressure head; andthe fixed region includes a preload chamber that internally retains the pressure head, a guide acceptor provided in the preload chamber to support the guide and guide the pressure head in an axial direction of the rotor, a steam passageway that communicates with the preload chamber and guides into the preload chamber the steam circulating through the steam turbine, and a spring that imparts an urging force to the pressure head. 3. The sealing device for the steam turbine according to claim 1, the sealing device comprising:a valve provided on a steam passageway for moving the movable region controls a supply rate of the steam;an operational state detector detects an operational state of the steam turbine; anda control device controls a moving distance of the movable region by controlling an opening angle of the valve in accordance with a signal from the operational state detector. 4. The sealing device for the steam turbine according to claim 3, wherein: the operational state detector is a rotor vibration detector that detects a vibration level of the rotor, the detector using the vibration level of the rotor to detect the operational state of the steam turbine; andthe control device, upon the rotor vibration level being equal to or less than a predetermined value, moves the movable region to a rotor axial position at which a clearance between the sealing fin and spacer reaches a preset value. 5. The sealing device for the steam turbine according to claim 3, wherein: the operational state detector is a temperature detector that detects a temperature of the steam, the detector using the temperature of the steam to detect the operational state of the steam turbine; andthe control device, upon the steam temperature exceeding a predetermined value, moves the movable region to a rotor axial position at which a clearance between the sealing fin and spacer reaches a preset value. 6. The sealing device for the steam turbine according to claim 3, wherein: the operational state detector is a pressure detector that detects a pressure of the steam, the detector using the steam pressure to detect the operational state of the steam turbine; andthe control device, upon the steam pressure exceeding a predetermined value, moves the movable region to a rotor axial position at which a clearance between the sealing fin and spacer reaches a preset value. 7. The sealing device for the steam turbine according to claim 3, wherein: the operational state detector is a differential thermal elongation detector that detects a difference in axial thermal elongation level between the rotor and the casing, the detector using the differential thermal elongation level to detect the operational state of the steam turbine; andthe control device, upon the differential thermal elongation level exceeding a predetermined value, moves the movable region to a rotor axial position at which a clearance between the sealing fin and spacer reaches a preset value. 8. The sealing device for the steam turbine according to claim 1, wherein the free-cutting metal is a gas-permeable metal. 9. A method for controlling 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 and being inclusive of 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, the method comprising: a sequence which, when the sealing fins are disposed on the fixed region, includes in addition to executing steady load operation of the steam turbine, moving each of the sealing fins of the fixed region in the axial direction of the rotor so that the sealing fin moves to a position at which a clearance between the sealing fin and spacer that face each other reaches a preset value;a sequence which, when the spacers are disposed on the fixed region, includes in addition to executing steady load operation of the steam turbine, moving each of the spacers of the fixed region in an axial direction of the rotor so that the spacer moves to a position at which a clearance between the sealing fin and spacer that face each other reaches a preset value;a sequence which, when the sealing fins and the spacers are disposed on the fixed region, includes in addition to executing steady load operation of the steam turbine, moving each of the sealing fins and spacers of the fixed region in an axial direction of the rotor so that the spacer moves to a position at which a clearance between the sealing fin and spacer that face each other reaches a preset value: anda sequence which detects vibration of the rotor,wherein, upon a level of the rotor vibration being equal to or lower than a predetermined rotor vibration level, the sealing fin or spacer on the fixed region side moves to the position at which the clearance between the sealing fin and spacer that face each other reaches the preset value. 10. The sealing device control method according to claim 9, further comprising: a sequence which detects a temperature of steam,wherein, upon the steam temperature being equal to or higher than a predetermined steam temperature, the sealing fin or spacer on the fixed region side moves to the position at which the clearance between the sealing fin and spacer that face each other reaches the preset value. 11. The sealing device control method according to claim 9, further comprising: a sequence which detects a pressure of steam circulating through the steam turbine,wherein, upon the steam pressure being equal to or greater than a predetermined pressure value, the sealing fin or spacer on the fixed region side moves to the position at which the clearance between the sealing fin and spacer that face each other reaches the preset value. 12. The sealing device control method according to claim 9, further comprising: a sequence which detects a difference in axial thermal elongation level between the rotor and the casing,wherein, upon the differential thermal elongation level being equal to or higher than a predetermined differential thermal elongation level, the sealing fin or spacer on the fixed region side moves to the position at which the clearance between the sealing fin and spacer that face each other reaches the preset value. 13. The sealing device control method according to claim 9, wherein the free-cutting metal is a gas-permeable metal. 14. 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 projected in the radial direction of the rotor; andspacers provided in both or either of the rotating region and the fixed region, both facing the sealing fins, the spacers each using a free-cutting metal, wherein when the fixed region includes the sealing fins, upon a driving mechanism, the sealing fins included in the fixed region move to positions opposed to surfaces of the spacer that are not cut, from positions opposed to regions of the spacer that are already cut, in an axial direction of the rotor with respect to the rotating region; andwhen the fixed region includes the spacers, since the spacers included in the fixed region move in the axial direction of the rotor with respect to the rotating region by the driving mechanism, the sealing fins included in the rotating region move to positions opposed to surfaces of the spacer that are not cut, from positions opposed to regions of the spacer that are already cut.
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이 특허에 인용된 특허 (4)
Glahn, Jorn A.; Munsell, Peter M., Gas turbine engine systems involving hydrostatic face seals with integrated back-up seals.
Casavant, Matthew Stephen; Johnson, David Martin, System and method relating to axial positioning turbine casings and blade tip clearance in gas turbine engines.
Casavant, Matthew Stephen; Black, Kenneth Damon; Cox, Christopher Paul, Systems relating to axial positioning turbine casings and blade tip clearance in gas turbine engines.
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