JP2012021445A - Sealing structure for steam turbine and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing structure and a control method therefor capable of improving sealing performance between a rotating part and a fixed part, preventing fins from being damaged, and preventing increases in the amount of steam leakage from any of clearances newly formed by further abrasion of an abradable material.SOLUTION: The sealing structure is provided in which free-cutting spacers 28 on a sealing base plate 25 side and sealing fins 24 on a rotor 18 side are configured to be opposed to each other, and the sealing base plate 25 is disposed so as to be movable in an axial direction of the rotor 18. When a load of a steam turbine 3 increases, a pressure head 30 moves in an axial steam-pressure loading direction of the rotor 18 and the sealing base plate 25 connected to the pressure head 30 moves in the axial steam-pressure loading direction. Since the free-cutting spacers 28 at positions opposed to those of the sealing fins 24 existing after the movement of the sealing base plate are maintained in a non-contact state, clearances between the sealing fins 24 and the free-cutting spacers 28 are dimensionally minimized.

Description

  The present invention relates to a seal structure for a steam turbine.

  In the case of a power plant that generates electricity by rotating a turbine (steam turbine) with steam generated by a boiler, the steam turbine includes a high-pressure turbine, an intermediate-pressure turbine, and a low-pressure turbine from the upstream side of the steam flow. The rotated steam is introduced into the condenser via the exhaust chamber, is condensed in the condenser, becomes feed water, and returns to the steam generator.

  In a steam turbine constituting such a power plant, a stationary blade fixed to the inside of a casing is arranged between a moving blade and a moving blade that rotate integrally with a rotor, and a paragraph composed of the stationary blade and the moving blade is provided. It is formed.

  The steam introduced into the casing flows inside the casing of the steam turbine, and expands while alternately passing between the stationary blade and the moving blade fixed to the rotor that is rotatably supported by the casing. Rotate. The moving blade provided on the most downstream side of the rotor, that is, the steam that has passed through the moving blade in the final stage is configured to be discharged out of the casing.

  More specifically, the stationary blade is often fixed in a diaphragm installed inside the casing, and the moving blade is installed and fixed on the outer surface of the rotor so as to rotate integrally with the rotor. From the viewpoint of ease of maintenance, the casing and the diaphragm are often divided into two parts.

  In such a steam turbine, the steam rotates the rotor blades to rotate the rotor. Therefore, in order to use the steam efficiently, for example, a diaphragm and a rotor that contain a stationary blade and are held in a casing Improve the sealing performance between the fixed part and the rotating part so as to minimize the leakage of steam from the clearance between the fixed part and the rotating part, such as between the rotor blade tip and the casing. Is required.

  However, if the clearance between the rotating part and the fixed part is reduced to improve the sealing performance, the problem that the seal fin and the rotor come into contact with each other and the fin is damaged easily occurs. This causes the problem of increased steam leakage.

  As a cause of contact of the fins between the rotating part and the fixed part, thermal deformation of a casing, a diaphragm or the like is considered. It is well known that a thermal difference occurs between the top and bottom of the casing during operation, so that a temperature difference occurs and the upper side is larger than the lower side, and the thermal bending deformation called the dorsum is generated. Thereby, a casing (fixed part) position raises relatively with respect to a rotor (rotating part), and becomes a cause which a fin contacts.

  A temperature difference is generated in the radial direction of the diaphragm, and the inner peripheral temperature becomes higher than the outer peripheral temperature, so that the inner periphery extends from the outer periphery of the diaphragm. Due to this thermal elongation, the diaphragm undergoes bending deformation, and the position of the inner peripheral surface of the lower diaphragm rises relative to the end position of the outer peripheral dividing surface. In the lower diaphragm, the end of the outer peripheral dividing surface is fixed to the inside of the casing, and the inner peripheral position of the lower diaphragm rises relative to the casing position. Eventually, the diaphragm (fixed part) rises relative to the rotor (rotating part), which contributes to the contact of the fins.

  In recent years, steam turbine operation has been required to shorten the start-up time, and the steam temperature is increased and the flow rate is increased in a shorter time than before. Particularly in this case, a temperature difference tends to occur in the radial direction of the diaphragm, and thermal deformation easily occurs.

  This thermal deformation raises the position of the casing (fixed part) relative to the rotor (rotating part), which contributes to contact of the fins.

  In order to cope with such a problem, a labyrinth seal device having fins (seal fins) is conventionally provided between a rotating part such as a rotor and a fixed part such as a diaphragm, and a comfortable cutting performance is provided at a position facing the fins. A technology of a sealing device using a machinable metal member (abradable material) is disclosed (for example, see Patent Document 1). According to the technique disclosed in Patent Document 1, even if the fin and the abradable material come into contact with each other, the abradable material is cut by the fin, so that the fin is prevented from being damaged and the increase in steam leakage is reduced. There are effects such as being able to.

Japanese Patent Laid-Open No. 2002-228013

  However, if the fin and the abradable material are arranged so that the clearance between the rotating part and the fixed part becomes as small as possible to improve the sealing performance, the contact between the fin and the abradable material increases and the abradable material Since the material is free-cutting, the clearance for the free-cutting increases. Since the clearance increases due to free cutting, the amount of steam leakage from the increased clearance increases. In Patent Document 1, an increase in the amount of steam leakage from the clearance that is increased by free-cutting the abradable material is not considered.

  Also, if the clearance between the fin and the abradable material is increased in order to prevent contact between the fin and the abradable material, the clearance between the rotating part and the fixed part will increase and steam leakage will increase. Improve turbine efficiency of the turbine. Accordingly, the present invention further provides a seal structure in which the abradable material is further machined to prevent an increase in the amount of steam leakage from the increased clearance, to improve the sealing performance, and to improve the turbine efficiency of the steam turbine. It is an issue to provide.

  In order to solve the above-mentioned problems, the present invention is provided with a seal fin in a rotating part and / or a fixed part of a steam turbine, and a spacer using free-cutting metal in the rotating part or the fixed part facing the seal fin. The seal structure is provided with a seal fin or spacer provided in the fixed portion, wherein the seal device is movable in the rotor axial direction with respect to the rotating portion by the driving device.

  According to the present invention, even if the abradable material is free-cutting, there is no increase in clearance, an increase in the amount of steam leakage from the clearance can be prevented, the sealing performance can be improved, and the turbine efficiency of the steam turbine can be improved.

It is a schematic system diagram of a power plant provided with the steam turbine concerning this embodiment. It is a partial enlarged view of the steam turbine concerning this embodiment. It is a labyrinth seal enlarged view of FIG. It is a figure explaining the effect of this embodiment shown in FIG. It is another labyrinth seal enlarged view. It is a figure explaining the effect of this embodiment shown in FIG. It is another labyrinth seal enlarged view. It is the schematic which shows the front-end | tip of a moving blade. It is the schematic which shows one structural example of the labyrinth seal apparatus which flows in a pressure receiving chamber by flowing driving steam into a pressurized chamber from a high pressure steam supply source.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings as appropriate.

  FIG. 1 is a schematic system diagram illustrating an example of a power plant including a steam turbine according to the present embodiment. As shown in FIG. 1, the power plant 1 includes a boiler 2, a steam turbine 3 (a high pressure turbine 11, an intermediate pressure turbine 12, and a low pressure turbine 13), a generator 4, a condenser 5, and the like. The rotor 6 of the low-pressure turbine 13 is connected to the drive shaft 7 of the generator 4, and the generator 4 is driven by the rotation of the low-pressure turbine 13 to generate power.

  The boiler 2 is a steam generator, in which a reheater 8 is accommodated, and is connected to the inlet side of the high-pressure turbine 11 via a pipe 9. The outlet side of the high pressure turbine 11 is connected to the reheater 8 of the boiler 2 through the pipe 10. The reheater 8 is connected to the inlet side of the intermediate pressure turbine 12 via a pipe 14, and the outlet side of the intermediate pressure turbine 12 is connected to the inlet side of the low pressure turbine 13 via a pipe 47.

  The piping 9 and the piping 14 are provided with a control valve B, which functions as a control valve for controlling the amount of steam St flowing into the high-pressure turbine 11 and the intermediate-pressure turbine 12, respectively. These control valves B are controlled by the control device 15 to control the amount of steam St flowing into the high-pressure turbine 11 and the intermediate-pressure turbine 12.

  The steam St generated in the boiler 2 flows into the low-pressure turbine 13 via the high-pressure turbine 11 and the intermediate-pressure turbine 12 and rotates the rotor 6 provided in the low-pressure turbine 13. The steam St exhausted from the low-pressure turbine 13 by rotating the rotor 6 is condensed in the condenser 5 through the exhaust chamber 48 to become water (feed water), and then sent to the feed water heater 16 to supply water. It is heated by the heater 16 and is reintroduced into the boiler 2 that is a steam generator via another feed water heater, a high-pressure feed water pump, or the like.

  As shown in FIG. 2, in the steam turbine 3, a plurality of moving blades 17, 17,... Fixed in the direction along the outer periphery of the rotor 18 are arranged in a plurality of rows in the axial direction.

  Further, a casing 19 containing the rotor 18 and the moving blade 17 and a plurality of stationary blades 21, 21... Fixed to the casing 19 via a nozzle diaphragm outer ring 20 are provided. The stationary blades 21 and the moving blades 17 are alternately arranged in the axial direction of the rotor 18 to form a paragraph. The rotor 18 rotates in the circumferential direction.

  When the steam St generated in the boiler 2 flows into the casing 19 of the steam turbine 3, the steam St circulates alternately between the stationary blades 21 and the moving blades 17 while depressurizing and expanding, and rotates the rotor 18.

  The moving blade 17 provided on the most downstream side of the rotor 18, that is, the steam St that has passed through the moving blade 17 in the final stage is configured to be exhausted to the outside of the casing 19.

  In the steam turbine 3 configured in this manner, the rotor 18 is efficiently rotated by the steam St flowing inside the casing 19, so that the rotor 18 and the moving blades 17 that are rotating parts, the casing 19 that is a fixed part, and It is required to improve the sealing performance between the stationary blades 21 and suppress the amount of steam St (leakage steam) leaking from the clearance between the rotating part and the fixed part.

  For example, in order to reduce the rotational resistance against the rotation of the rotor 18, a clearance may be provided between the nozzle diaphragm inner ring 22 provided at the tip of the stationary blade 21 and the rotor 18, and this clearance is the steam flowing into the stationary blade 21. It causes St leaking steam.

  Since the steam St that becomes the leaked steam does not contribute to the rotation of the rotor 18, the turbine efficiency of the steam turbine 3 decreases when the amount of the leaked steam increases. Therefore, in order to improve the turbine efficiency of the steam turbine 3, it is preferable to reduce the amount of leaked steam.

  For this reason, a configuration in which a clearance between the rotor 18 and the stationary blade 21 is generally reduced by incorporating a seal device such as a labyrinth seal device 23 between the nozzle diaphragm inner ring 22 and the rotor 18 is common. With this configuration, the sealing performance between the rotor 18 and the stationary blade 21 can be improved, and the amount of leaked steam can be reduced.

  As shown in FIG. 3, a plurality of fixed seal fins 24... Are provided on the rotor 18 side of the high / low type labyrinth seal device 23 according to the present embodiment.

  A plurality of high portions 26 and low portions 27 formed in the circumferential direction along the axial direction of the rotor 18 are provided on the seal substrate 25 of the nozzle diaphragm inner ring 22 at predetermined intervals.

  Then, the high portion 26 and the low portion 27 on the seal substrate 25 side and the seal fin 24 on the rotor 18 side are arranged so as to face each other in the axial direction of the rotor 18.

  In this way, the labyrinth seal device 23 including a plurality of seal fins 24 is configured.

  Conventionally, the high portion 26 and the low portion 27 on the seal substrate 25 side and the seal fin 24 on the rotor 18 side are configured in a non-contact manner. With this configuration, a minute clearance is generated between the seal fin 24 and the seal substrate 25, and rotational resistance to rotation of the rotor 18 is reduced.

  However, the steam St passing through these clearances becomes leaked steam without contributing to the rotation of the rotor 18. And a steam leakage loss generate | occur | produces with leaking steam, and the turbine efficiency of the steam turbine 3 falls.

  Therefore, in this embodiment, a free-cutting spacer 28 (spacer) made of a free-cutting metal is attached between the seal fin 24 on the rotor 18 side and the seal substrate 25.

  Further, the sealing substrate 25 provided with the free-cutting spacer 28 is provided so as to be movable in the axial direction of the rotor 18.

  With this configuration, the free-cutting spacer 28 provided in the stationary blade 21 (see FIG. 2) that is a fixed portion can move in the axial direction with respect to the rotor 18 that is a rotating portion.

  The method for attaching the free-cutting spacer 28 to the seal substrate 25 is not limited, and may be fixed by brazing, for example.

  The free-cutting metal forming the free-cutting spacer 28 according to the present embodiment is a material (abradable material) excellent in machinability. For example, the free-cutting spacer 28 and the rotor 18 on the seal substrate 25 side. When the rotor 18 rotates with the tip of the side seal fin 24 in contact (contact state), for example, as shown in FIG. 4, the free-cutting spacer 28 is scraped and the seal fin 24 is not damaged.

  Here, in order to facilitate understanding of the present embodiment, a conventional technique and its problems will be described with reference to the drawings.

  In the prior art provided with a spacer made of a material having excellent machinability, such as an abradable material, at a position facing the seal fin 24, the free-cutting spacer 28 and the seal fin 24 are provided as shown in FIG. As a result of the contact, the free-cutting spacer 28 is cut and a clearance larger than the initial setting is generated on the seal fin 24. When the clearance is increased due to the contact in this way, the amount of steam leakage increases in the seal portion in accordance with the increase in the clearance, resulting in a problem that the turbine efficiency of the steam turbine decreases due to the increase in the amount of leakage. To do.

  That is, the following problems occur. (1) When the turbine is assembled, when a small amount of steam is introduced into the steam turbine with respect to the initial state, the free-cutting spacer 28 and the seal fin 24 (due to thermal deformation of the diaphragm, thermal deformation of the casing, thermal expansion of the rotor, etc.) 2) The process of contact between the free-cutting spacer 28 and the seal fin 24 is assumed in which contact is started and thermally stabilized after a lapse of time, (3) contact is terminated, and (4) a steady load position is reached. The It becomes possible to perform stable power generation by allowing high-temperature and high-pressure steam St to flow into the steam turbine in order to achieve a stable operation in a thermally stable state. As shown in FIG. 4A, the gap in this case is remarkably increased with respect to the gap in the initial state when the turbine is assembled (1).

  As a result, there is a problem that the amount of seal leakage during steady operation increases and the turbine efficiency decreases.

  The above is the problem of the prior art. Returning to the description of the present embodiment again.

  In the present embodiment, the free-cutting spacer 28 is configured to be movable in the axial direction with respect to the rotor 18 that is a rotating portion. For example, as shown in FIG. 4B, when a high-temperature and high-pressure steam St is caused to flow into the steam turbine so as to perform a steady operation after the contact is finished after the contact is completed, the free-cutting spacer 28 is used. Moves in the axial direction with respect to the rotor 18 which is a rotating part. Since the free-cutting spacer 28 at the position facing the position of the seal fin 24 after the movement is kept in a non-contact state, the clearance on the seal fin 24 is equal to the gap in the initial state. That is, even if the surface of the free-cutting spacer 28 is free-cut by contact, the seal gap during steady operation can be made equal to the gap in the initial state. Can be kept high.

  Thus, the free-cutting spacer 28 (spacer) is attached between the seal fin 24 on the rotor 18 side and the sealing substrate 25, and the sealing substrate 25 provided with the free-cutting spacer 28 can move in the axial direction of the rotor 18. As a result, even if the seal fin 24 and the free-cutting spacer 28 are in contact with each other, the amount of seal leakage during steady operation increases, and the problem of lowering turbine efficiency does not occur. Therefore, even if the surface of the free-cutting spacer 28 is free-cut to contact, the leakage amount does not increase and the turbine efficiency can be kept high.

  Furthermore, the seal substrate 25 according to the present embodiment is provided so as to be movable in the rotor axial direction with respect to the rotor 18. As shown in FIG. 3, a hollow pressurizing chamber 29 is formed in the nozzle diaphragm inner ring 22, and a pressure receiving head 30 that reciprocates in the rotor axial direction with respect to the rotor 18 is provided in the pressurizing chamber 29. Yes. The pressure receiving head 30 is elastically supported by a return spring 31 (biasing means), and is urged by the return spring 31 with a considerable urging force in a direction opposite to the pushing direction of the vapor pressure.

  The pressurizing chamber 29 is configured to communicate with the outside of the nozzle diaphragm inner ring 22 through the steam passage 46, so that the steam St flowing outside the nozzle diaphragm inner ring 22 flows into the pressurizing chamber 29. When the pressure of the steam St acts on the pressure receiving head 30, the pressure receiving head 30 is pushed by the steam pressure and moves in the rotor axial direction.

  A seal substrate 25 is attached to the pressure receiving head 30 at the inner circumferential tip. Further, the pressure receiving head 30 is provided with a guide 32. The guide 32 comes into contact with a guide receiver 33 projecting into the nozzle diaphragm inner ring 22, and the pressure receiving head 30 and the seal substrate 25 rotate due to the moment of vapor pressure received by the pressure receiving head 30 and the seal substrate 25. This makes it possible to smoothly reciprocate in the rotor axial direction.

  The guide 32 may be formed integrally with the pressure receiving head 30, for example. The method for attaching the pressure receiving head 30 seal substrate 25 is not limited. For example, the seal substrate 25 may be fixed to the pressure receiving head 30 with a screw (not shown).

  The movable portion is configured to include the pressure receiving head 30, the guide 32, and the seal substrate 25.

  When the pressure receiving head 30 is supported by the biasing force of the return spring 31 at a position opposite to the direction in which the vapor pressure is pushed, the seal substrate 25 is moved to a position opposite to the direction in which the vapor pressure is pushed. is there.

  The labyrinth seal device 23 in this embodiment includes a pressurizing chamber 29, a steam passage 46, a pressure receiving head 30, a guide 32, and a return spring 31 in addition to the seal substrate 25.

  Then, the seal structure including the labyrinth seal device 23 and the free-cutting spacer 28 on the seal substrate 25 side is incorporated into the steam turbine 3.

  When the steam St generated in the boiler 2 flows into the steam turbine 3, when the steam St passes between the stationary blade 21 and the moving blade 17, a part of the steam St flows through the steam passage 46 and enters the pressurized chamber 29. Inflow.

  If the force (pressing force) that moves the pressure receiving head 30 to the pressure of the steam St flowing into the pressurizing chamber 29 is smaller than the biasing force of the return spring 31, the return spring 31 causes the pressure receiving head 30 to move in the direction in which the steam pressure is pushed. It is supported at the opposite position.

  For example, when the load connected to the steam turbine 3 (see FIG. 1) increases and the pressure of the steam St flowing through the steam turbine 3 increases, the pressure of the steam St flowing into the pressurized chamber 29 also increases. When the pressing force for moving the pressure receiving head 30 in the axial direction of the rotor 18 by the pressure of the steam St becomes equal to or greater than the urging force of the return spring 31, the pressure receiving head 30 moves in the axial direction of the rotor 18 by the pressure of the steam St. The seal substrate 25 connected to the pressure receiving head 30 moves in the direction of the pressure axis of the vapor pressure.

When the pressure receiving head 30 is moved to the stop position in the vapor pressure pressing direction, the surface of the non-contact free-cutting spacer 28 on the seal substrate 25 side is opposed to the rotor 18 side seal fin 24. When the pressure of the steam St flowing into the pressurizing chamber 29 is increased, the gap between the seal fin 24 and the free-cutting spacer 28 facing each other can be set to the initial setting state.
And the clearance between the seal fin 24 and the free-cutting spacer 28 is minimized, and the sealing performance between the stationary blade 21 and the rotor 18 is improved.

  Note that the steam St flowing through the steam turbine 3 expands from the upstream toward the downstream and depressurizes. Therefore, the return spring 31 provided in the labyrinth seal device 23 of the stationary blade 21 is attached to the downstream of the steam St flow. The structure which weakens power may be sufficient.

  In the steam turbine 3 incorporating the seal structure configured as described above, when the steam St pressure is low, the free-cutting spacer 28 on the seal substrate 25 side steams against the seal fin 24 on the rotor 18 side. The position is in the direction opposite to the direction in which the pressure is pushed.

  Therefore, in the thermally unstable state at the time of start-up, the free-cutting spacer 28 on the seal substrate 25 side is in a position opposite to the direction in which the vapor pressure is pushed with respect to the seal fin 24 on the rotor 18 side. The seal fin 24 and the free-cutting spacer 28 may come into contact with each other due to deformation.

  At this time, although the free-cutting spacer 28 is dented due to contact, the seal fin 24 is not damaged because of contact with the free-cutting spacer 28.

When the load of the steam turbine 3 increases and the pressure of the steam St increases, the free-cutting spacer 28 moves to a stop position in the pressure axis direction of the steam pressure, and the clearance between the seal fin 24 and the free-cutting spacer 28 is minimized. In this state, the sealing performance between the stationary blade 21 and the rotor 18 is improved.
Therefore, the turbine efficiency of the steam turbine 3 is improved.

  As a method of using the load of the steam turbine 3, it is also conceivable to divide the seal substrate constituting the labyrinth seal device in the circumferential direction so as to be movable in the radial direction with respect to the rotor. That is, in the thermally unstable state at the time of start-up, the sealing substrate is pressed to a position away from the rotor in the radial direction by using the biasing force of the spring, the load of the steam turbine 3 is increased and the pressure of the steam St is increased. In this case, the seal substrate is configured to move to a position close to the rotor by pressing the vapor pressure. As a result, in the thermally unstable state at the time of start-up, the seal substrate is separated from the rotor to prevent contact with the rotor, and when the pressure of the steam St increases, the substrate approaches the rotor and the amount of leakage from the seal gap Can be reduced.

  However, in the case of this configuration, if the seal substrate is greatly separated in the radial direction, the circumferentially divided surface of the seal substrate opens widely, a large amount of steam leaks, and sufficient steam pressure cannot be obtained. The amount of movement in the radial direction cannot be increased too much.

  The amount of deformation may increase due to the above-described thermal deformation of the casing or diaphragm. In this case, contact with the rotor occurs, and if a free-cutting spacer is installed at a position facing the fin, the free-cutting spacer Will be free-cut. For this reason, even if the pressure of the steam St increases and the seal substrate moves to a position close to the rotor, a free-cutting recess is generated in the free-cutting spacer at the fin-facing position, and the gap at the fin tip portion eventually becomes large, The amount of leakage cannot be reduced.

  In the case of the present invention, there is no particular limitation on the amount of axial movement of the pressure receiving head 30 and the seal substrate 25. Therefore, even when there is a large difference in elongation between the rotor and the casing, it can be easily handled.

  The free-cutting spacer 28 may be a free-cutting spacer 28 using a breathable metal. The air-permeable metal is a metal material that has a structure in which porous metal space portions (pores) are connected, and allows gas (vapor St) to pass therethrough. Since the breathable metal is a material excellent in machinability, the free-cutting spacer 28 can be configured. By using the free-cutting spacer 28 using a breathable metal, not only can the seal fin 24 be prevented from being damaged, but also the contact heat generated by the contact between the seal fin 24 and the free-cutting spacer 28 can be removed. Thermal deformation can be prevented.

  As described above, the configuration example in which the free-cutting spacer 28 is attached to the labyrinth seal device 23 and the seal substrate 25 constituting the labyrinth seal device 23 are provided on the nozzle diaphragm inner ring side 22 so as to be movable in the axial direction with respect to the rotor 18. Although one configuration example has been described, the configuration of the present invention is not limited to this.

  For example, the labyrinth seal device 23 includes a high-low labyrinth seal device shown in FIG. 5 in addition to the shape shown in FIG. The present invention can also be applied to the high-low labyrinth seal device shown in FIG.

  In the present embodiment shown in FIG. 5, a free-cutting spacer 28 (spacer) made of a free-cutting metal is attached between the seal fin 34 on the seal substrate 25 side and the high portion 35 and the low portion 36 of the rotor 18. .

  Further, the seal substrate 25 provided with the seal fins 34 is provided so as to be movable in the rotor axial direction.

  The free-cutting metal forming the free-cutting spacer 28 according to the present embodiment is a material (abradable material) excellent in machinability, for example, the tip of the seal fin 34 on the seal substrate 25 side and the rotor 18. When the rotor 18 rotates with the free-cutting spacer 28 on the side in contact, for example, as shown in FIG. 6, the free-cutting spacer 28 is cut and the seal fins 34 are not damaged.

  Here, in order to facilitate understanding of the present embodiment, a conventional technique and its problems will be described with reference to the drawings.

  In the conventional technology in which a spacer made of a material having excellent machinability such as an abradable material is provided at a position facing the seal fin 34, as shown in FIG. 6A, the free-cutting spacer 28, the seal fin 34, As a result of this contact, the free-cutting spacer 28 is scraped, and a clearance larger than the initial setting is generated on the seal fin 34. Since the amount of steam leakage increases in the seal portion in accordance with the increase in the clearance, there arises a problem that the turbine efficiency of the steam turbine decreases due to the increase in the amount of leakage.

  As described above, the following problems occur. (1) When the steam is assembled, when a small amount of steam is introduced into the steam turbine with respect to the initial state, the free-cutting spacer 28 and the seal fin 34 (due to thermal deformation of the diaphragm, thermal deformation of the casing, thermal expansion of the rotor, etc.) 2) The process of contact between the free-cutting spacer 28 and the seal fin 34 is assumed in which the contact is started and thermally stabilized after a lapse of time, (3) the contact is terminated, and (4) the steady load position is reached. The It becomes possible to perform stable power generation by allowing high-temperature and high-pressure steam St to flow into the steam turbine in order to achieve a stable operation in a thermally stable state. As shown in FIG. 4A, the gap in this case is remarkably increased with respect to the gap in the initial state when the turbine is assembled (1).

  As a result, there is a problem that the amount of seal leakage during steady operation increases and the turbine efficiency decreases. The above is the problem of the prior art. Returning to the description of the present embodiment again.

  In the present embodiment, the seal fin 34 is configured to be movable in the axial direction with respect to the rotor 18. For example, as shown in FIG. 6B, when the high temperature / high pressure steam St is caused to flow into the steam turbine in order to perform the steady operation after the contact is completed after the contact is completed, the seal fin 34 rotates. It moves in the axial direction with respect to the free-cutting spacer 28 on the rotor 18 as a part. Since the free-cutting spacer 28 at the position facing the position of the seal fin 34 after moving is kept in a non-contact state, the clearance on the seal fin 34 is equal to the gap in the initial state. That is, even if the surface of the free-cutting spacer 28 is free-cut by contact, the seal gap during steady operation can be made equal to the gap in the initial state. Can be kept high.

  As described above, the seal substrate 25 provided with the seal fins 34 is provided so as to be movable in the axial direction of the rotor 18, so that even when the seal fins 34 and the free-cutting spacers 28 are in contact with each other, The amount of leakage increases and the problem of lowering turbine efficiency does not occur. Therefore, even if the surface of the free-cutting spacer 28 is free-cut to contact, the leakage amount does not increase and the turbine efficiency can be kept high.

  Furthermore, the seal substrate 25 according to the present embodiment is provided so as to be movable in the axial direction with respect to the rotor 18. As shown in FIG. 5, a hollow pressurizing chamber 29 is formed in the nozzle diaphragm inner ring 22, and a pressure receiving head 30 that reciprocates in the rotor axial direction with respect to the rotor 18 is provided in the pressurizing chamber 29. Yes. The pressure receiving head 30 is elastically supported by a return spring 31 and is urged by a considerable urging force in the direction opposite to the pushing direction of the vapor pressure.

  The pressurizing chamber 29 is configured to communicate with the outside of the nozzle diaphragm inner ring side 22 through the steam passage 46 so that the steam St flowing outside the nozzle diaphragm inner ring side 22 flows into the pressurizing chamber 29. When the pressure of the steam St acts on the pressure receiving head 30, the pressure receiving head 30 is pushed by the steam pressure and moves in the rotor axial direction.

  A seal substrate 25 is attached to the tip of the pressure receiving head 30. Further, the pressure receiving head 30 is provided with a guide 32. The guide 32 comes into contact with a guide receiver 33 protruding inside the nozzle diaphragm inner ring side 22, and the pressure receiving head 30 and the seal substrate 25 rotate due to the moment of the vapor pressure received by the pressure receiving head 30 and the seal substrate 25, and the posture is unstable. And reciprocating smoothly in the rotor axial direction.

  The movable portion is configured to include the pressure receiving head 30, the guide 32, and the seal substrate 25.

  When the pressure receiving head 30 is supported by the biasing force of the return spring 31 at a position opposite to the direction in which the vapor pressure is pushed, the seal substrate 25 is moved to a position opposite to the direction in which the vapor pressure is pushed. is there.

  The labyrinth seal device 23 in this embodiment includes a pressurizing chamber 29, a steam passage 46, a pressure receiving head 30, a guide 32, and a return spring 31 in addition to the seal substrate 25.

  A seal structure including the labyrinth seal device 23 and the free-cutting spacer 28 on the rotor 18 side is incorporated into the steam turbine 3.

  When the steam St generated in the boiler 2 flows into the steam turbine 3, when the steam St passes between the stationary blade 21 and the moving blade 17, a part of the steam St flows through the steam passage 46 and enters the pressurized chamber 29. Inflow.

  If the force (pressing force) that moves the pressure receiving head 30 to the pressure of the steam St flowing into the pressurizing chamber 29 is smaller than the biasing force of the return spring 31, the return spring 31 causes the pressure receiving head 30 to move in the direction in which the steam pressure is pushed. It is supported at the opposite position.

  For example, when the load connected to the steam turbine 3 increases and the pressure of the steam St flowing through the steam turbine 3 increases, the pressure of the steam St flowing into the pressurized chamber 29 also increases. When the pressing force for moving the pressure receiving head 30 in the axial direction of the rotor 18 by the pressure of the steam St becomes equal to or greater than the urging force of the return spring 31, the pressure receiving head 30 moves in the axial direction of the rotor 18 by the pressure of the steam St. The seal substrate 25 connected to the pressure receiving head 30 moves in the direction of the pressure axis of the vapor pressure.

When the pressure receiving head 30 moves to the stop position in the vapor pressure pressing direction, the surface of the non-contact free-cutting spacer 28 on the rotor 18 side is opposed to the seal fin 25 side seal fin 34. When the pressure of the steam St flowing into the pressurizing chamber 29 is increased, the gap between the seal fin 34 and the free-cutting spacer 28 facing each other can be set to the initial setting state.
Further, the clearance between the seal fin 34 and the free-cutting spacer 28 is minimized, and the sealing performance between the stationary blade 21 and the rotor 18 is improved.

  Note that the steam St flowing through the steam turbine 3 expands from the upstream toward the downstream and depressurizes. Therefore, the return spring 31 provided in the labyrinth seal device 23 of the stationary blade 21 is attached to the downstream of the steam St flow. The structure which weakens power may be sufficient.

  In the steam turbine 3 incorporating the seal structure configured as described above, when the steam St pressure is low, the seal fin 34 on the seal substrate 25 side steams against the free-cutting spacer 28 on the rotor 18 side. The position is in the direction opposite to the direction in which the pressure is pushed.

  Therefore, in the thermally unstable state at the time of start-up, the steam fins 34 on the seal substrate 25 side and the free-cutting spacer 28 on the rotor 18 side are in positions opposite to the direction in which the vapor pressure is pushed, and in this position, thermal deformation occurs. As a result, the seal fin 34 and the free-cutting spacer 28 may come into contact with each other.

  At this time, although the free-cutting spacer 28 is dented by contact, the seal-fin 34 is not damaged because of contact with the free-cutting spacer 28.

  When the load of the steam turbine 3 increases and the pressure of the steam St increases, the seal fin 34 moves to a stop position in the pressure axis direction of the steam pressure, and the clearance between the seal fin 34 and the free-cutting spacer 28 is minimized. Thus, the sealing performance between the stationary blade 21 and the rotor 6 is improved. Therefore, the turbine efficiency of the steam turbine 3 is improved.

  As the free-cutting spacer 28, a free-cutting spacer 28 using a breathable metal can be used. Since the breathable metal is a material excellent in machinability, the free-cutting spacer 28 can be configured. By using the free-cutting spacer 28 using a breathable metal, not only can the seal fin 34 be prevented from being damaged, but also the contact heat generated by the contact between the seal fin 34 and the free-cutting spacer 28 can be removed. Thermal deformation can be prevented.

  As described above, one configuration example in which the free-cutting spacer 28 is attached to the rotor 18 and one configuration in which the nozzle substrate inner ring 22 is provided so that the seal substrate 25 constituting the labyrinth seal device 23 is movable in the axial direction with respect to the rotor 18. Although an example has been described, the configuration of the present invention is not limited to this.

  For example, the labyrinth seal device 23 includes a high-low type labyrinth seal device shown in FIG. 7 in addition to the shape shown in FIGS. The present invention can also be applied to a high-low labyrinth seal device shown in FIG.

  As shown in FIG. 7, the nozzle diaphragm inner ring 22 according to the present embodiment includes a seal substrate 25 having a plurality of seal fins 34.

  The seal substrate 25 is provided with a plurality of grooves 37... Formed in the circumferential direction along the axial direction of the rotor 18 at predetermined intervals, and the seal fins 34 are caulked in each of the plurality of grooves 37. And fix.

  Further, the rotor 18 is provided with a plurality of grooves 38 formed in the circumferential direction along the axial direction of the rotor 18 at predetermined intervals, and the seal fins 24 are caulked in each of the plurality of grooves 38. And fix.

  The seal fins 34 on the seal substrate 25 side and the seal fins 24 on the rotor 18 side are arranged so as to alternately overlap in the axial direction of the rotor 18.

  In this way, the labyrinth seal device 23 is configured including the seal substrate 25 provided with a plurality of seal fins 34.

  A free-cutting spacer 28 (spacer) made of a free-cutting metal is attached between the seal fin 34 on the seal substrate 25 side and the rotor 18 and between the seal fin 24 on the rotor 18 side and the seal substrate 25.

  Further, the seal substrate 25 provided with the seal fins 34 and the free-cutting spacers 28 is provided so as to be movable in the rotor axial direction.

  With this configuration, any of the effects described in the embodiment of the present invention shown in FIGS. 3 and 5 can be obtained.

  That is, the labyrinth seal device 23 in the present embodiment includes a pressurizing chamber 29, a steam passage 46, a pressure receiving head 30, a guide 32, and a return spring 31 in addition to the seal substrate 25.

  Then, the seal structure including the labyrinth seal device 23 and the free-cutting spacer 28 on the rotor 18 side is incorporated into the steam turbine 3 (see FIG. 1).

  When the steam St generated in the boiler 2 flows into the steam turbine 3, when the steam St passes between the stationary blade 21 and the moving blade 17, a part of the steam St flows through the steam passage 46 and enters the pressurized chamber 29. Inflow.

  If the force (pressing force) that moves the pressure receiving head 30 to the pressure of the steam St flowing into the pressurizing chamber 29 is smaller than the biasing force of the return spring 31, the return spring 31 causes the pressure receiving head 30 to move in the direction in which the steam pressure is pushed. It is supported at the opposite position.

  For example, when the load connected to the steam turbine 3 increases and the pressure of the steam St flowing through the steam turbine 3 increases, the pressure of the steam St flowing into the pressurized chamber 29 also increases.

  When the pressure of the steam St moves the pressure receiving head 30 in the axial direction of the rotor 18 more than the urging force of the return spring 31, the pressure receiving head 30 moves in the axial direction of the rotor 18 with the pressure of the steam St. Then, the seal substrate 25 connected to the pressure receiving head 30 moves in the direction of the pressure axis of the vapor pressure.

  At this position, the heat-deformable spacer 28 facing the seal fins 34 on the seal substrate 25 and the seal fins 24 on the rotor 18 can come into contact with each other due to thermal deformation.

  At this time, although the free-cutting spacer 28 is dented by contact, the seal-fin 34 and the seal fin 24 are not damaged because of contact with the free-cutting spacer 28.

  After becoming thermally stable, the pressure of the steam St is increased to increase the load of the steam turbine 3. When the pressure of the steam St increases and the pressure receiving head 30 moves to the stop position in the direction of pressing the steam pressure, the free-cutting spacer 28 in the non-contact state on the rotor 18 side on the seal fin 34 on the seal substrate 25 side. When the surface of the non-contact free-cutting spacer 28 on the seal substrate 25 side is made to face the seal fin 24 on the rotor 18 side, the pressure of the steam St flowing into the pressurizing chamber 29 increases. The gap between the seal fins 34 facing each other and the free-cutting spacers 28 facing the seal fins 24 can be set to the initial setting state. Further, the clearance between the seal fin 34 and the free-cutting spacer 28 is minimized, and the sealing performance between the stationary blade 21 and the rotor 18 is improved.

  As the free-cutting spacer 28, a free-cutting spacer 28 using a breathable metal can be used. By using the free-cutting spacer 28 made of a breathable metal, not only is the damage of the seal fins 34 and the seal fins 24 prevented, but also the contact heat generated by the contact between the seal fins 34 and the seal fins 24 and the free-cutting spacers 28. And can prevent thermal deformation due to contact heat generation.

  The present embodiment can also be applied to a labyrinth seal device provided between the nozzle diaphragm outer ring 20 (see FIG. 2) and the moving blade 17 (see FIG. 2).

  As shown in FIG. 8, the seal substrate 25 is, for example, a high-low type, and the seal substrate 25 includes a plurality of high portions 26... Having a shape along the rotation direction of the rotor blade 17, that is, the circumferential direction. .. Are formed side by side in the axial direction of the rotor 18.

  A free-cutting spacer 28 is attached to each of the high portion 26 and the low portion 27 in a shape along the circumferential direction.

  The free-cutting spacer 28 provided in the casing 19 (see FIG. 2) that is a fixed part is configured to be movable in the rotor axial direction with respect to the rotor blade 17 that is a rotating part.

  A plurality of seal fins 40... Stand on the cover 39 of the rotor blade 17 along the circumferential direction at positions facing the high portions 26... And the low portions 27. It is provided.

  A pressure chamber 29 is formed in the nozzle diaphragm outer ring 20, and a pressure receiving head 30 that reciprocates in the rotor axial direction with respect to the rotor blade 17 is provided inside the pressure chamber 29. The pressure receiving head 30 is elastically supported by a return spring 31 (biasing means), and is urged by the return spring 31 in a direction opposite to the pushing direction of the vapor pressure.

  The pressurizing chamber 29 is configured to communicate with the outside of the nozzle diaphragm outer ring 20 through the steam passage 46 so that the steam St flowing outside the nozzle diaphragm outer ring 20 flows into the pressurizing chamber 29. When the pressure of the steam St acts on the pressure receiving head 30, the pressure receiving head 30 is pushed by the steam pressure and moves in the rotor axial direction.

  A seal substrate 25 is attached to the tip of the pressure receiving head 30. Further, the pressure receiving head 30 is provided with a guide 32. The guide 32 comes into contact with a guide receiver 41 projecting into the nozzle diaphragm outer ring 20, and the pressure receiving head 30 and the seal substrate 25 rotate due to the moment of the vapor pressure received by the pressure receiving head 30 and the seal substrate 25. This makes it possible to smoothly reciprocate in the rotor axial direction.

  The guide 32 may be formed integrally with the pressure receiving head 30, for example. The method for attaching the seal substrate 25 to the pressure receiving head 30 is not limited. For example, the seal substrate 25 may be fixed to the pressure receiving head 30 with a screw (not shown).

  The movable portion is configured to include the pressure receiving head 30, the guide 32, and the seal substrate 25.

  The labyrinth seal device 23 includes the seal substrate 25, the pressure receiving head 30, the guide 32, the return spring 31, the pressurizing chamber 29, and the steam passage 46.

  The steam turbine 3 (see FIG. 1) incorporates a seal structure including the labyrinth seal device 23 and the seal fins 40 on the moving blade 17 side.

  When the pressure receiving head 30 of the labyrinth seal device 23 is supported by the biasing force of the return spring 31 at a position opposite to the direction in which the steam pressure is pushed, the seal substrate 25 is in the direction opposite to the direction in which the steam pressure is pushed from the moving blade 17. It is in the state moved to position.

  When the steam St generated in the boiler 2 (see FIG. 1) flows into the steam turbine 3 (see FIG. 1), a part of the steam St flows through the steam passage 46 when the steam St passes outside the outer ring 20 of the nozzle diaphragm. Then, it flows into the pressurizing chamber 29.

  If the pressure of the steam St flowing into the pressurizing chamber 29 is smaller than the urging force of the return spring 31 to move the pressure receiving head 30 in the steam pressing axis direction, the return spring 31 causes the pressure receiving head 30 to It is supported at a position opposite to the pushing direction.

  When the pressure receiving head 30 is supported by a biasing force of the return spring 31 at a position opposite to the direction in which the vapor pressure is pushed, the seal substrate 25 is moved to a position opposite to the direction in which the vapor pressure is pushed. The free-cutting spacers 28 on the seal substrate 25 side facing each other have moved to positions opposite to the direction in which the vapor pressure is pushed with respect to the seal fins 40 on the cover 39 side of the rotor blade 17.

  In this position, the seal fin 40 on the cover 39 side of the moving blade 17 facing the free-cutting spacer 28 on the seal substrate 25 can be brought into contact with the seal substrate 25 due to thermal deformation.

  At this time, although the free-cutting spacer 28 is dented by contact, the seal fin 40 is not damaged because of contact with the free-cutting spacer 28.

  When the pressure of the steam St flowing into the steam turbine 3 (see FIG. 1) increases, the pressure of the steam St flowing into the pressurizing chamber 29 also increases. When the pressure of the steam St moves the pressure receiving head 30 in the direction of the steam pressing axis becomes equal to or greater than the urging force of the return spring 31, the pressure receiving head 30 moves in the axial direction with the pressure of the steam St, and the pressure receiving head 30. The seal substrate 25 connected to the nozzle moves in the direction of the steam pressing axis.

  When the pressure of the steam St increases and the pressure receiving head 30 moves to the stop position in the direction of pressing the steam pressure, the non-contact state on the seal substrate 25 side is placed on the seal fin 40 on the cover 39 side of the rotor blade 17. When configured to face the surface of the free-cutting spacer 28, when the pressure of the steam St flowing into the pressurizing chamber 29 increases, the gap between the free-cutting spacer 28 facing the opposing seal fin 40 is set to the initial setting state. can do.

  The clearance between the cover 39 of the moving blade 17 and the seal substrate 25 is minimized, and the sealing performance between the nozzle diaphragm outer ring 20 and the moving blade 17 is improved.

  This improves the turbine efficiency of the steam turbine.

  Further, since the steam St flowing in the steam turbine 3 (see FIG. 1) expands and depressurizes from the upstream to the downstream, the downstream of the flow of the steam St as in the labyrinth seal device 23 shown in FIG. As shown, the urging force of the return spring 31 may be weakened.

  The labyrinth seal device 23 shown in FIG. 8 has a structure in which the free-cutting spacer 28 is attached to the seal substrate 25 and the cover 39 is provided with the seal fin 40, but the seal substrate 25 is provided with the seal fin, The structure which a free-cutting spacer is attached to 39 may be sufficient.

  Alternatively, the seal substrate 25 and the cover 39 may be provided with seal fins. In this case, a free-cutting spacer may be attached to the position of the cover 39 facing the seal fin on the seal substrate 25 side and the position of the seal substrate 25 facing the seal fin on the cover 39 side.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and appropriate design changes can be made without departing from the spirit of the invention.

  Further, in the labyrinth seal device 23 shown in FIG. 7, the pressure receiving head 30 is configured to be driven by the pressure of the steam St flowing through the steam turbine 3. For example, as shown in FIG. The configuration may be such that the pressure receiving head 30 is moved in the direction of the steam load axis by the pressure of high-pressure steam (driving steam) for driving the pressure receiving head 30 flowing into the pressure chamber 29.

  The labyrinth seal device 23 shown in FIG. 9 includes a pressurizing chamber 29, a pressure receiving head 30, such as a return spring 31, a seal substrate 25, a valve control device 42, an operating state detection device 44, a high-pressure steam supply source 45, and an electromagnetic valve 43. Consists of including.

  The seal substrate 25 has the same configuration as the seal substrate 25 of the labyrinth seal device 23 shown in FIG.

  The steam turbine 3 incorporates a labyrinth seal device 23, a seal structure including the seal fin 24 and the free-cutting spacer 28 on the rotor 18 side.

  A high pressure steam supply source 45 is connected to the pressurizing chamber 29 via an electromagnetic valve 43. Further, a valve control device 42 that controls opening and closing of the electromagnetic valve 43 is provided.

  The valve control device 42 is preferably configured to control opening and closing of the electromagnetic valve 43 based on the operation state of the steam turbine 3, and includes an operation state detection device 44 that detects the operation state of the steam turbine 3.

  According to this configuration, the valve control device 42 can move the movable portion including the pressure receiving head 30 and the seal substrate 25 in the axial direction of the rotor 18 based on the operating state of the steam turbine 3. For example, not only the steam pressure but also the steam temperature, the vibration of the rotor 18 and the like can be used to discriminate an operating state that becomes unstable due to casing thermal deformation, diaphragm thermal deformation, or the like. Furthermore, not only the casing thermal deformation and diaphragm thermal deformation, but also the thermal expansion difference amount obtained by subtracting the casing axial thermal elongation amount from the rotor axial thermal elongation amount can also be used for discriminating the operating state in which it becomes unstable. It becomes like this.

  A driving device is configured including the pressurizing chamber 29, the valve control device 42, the high-pressure steam supply source 45, and the electromagnetic valve 43.

  The operating state of the steam turbine 3 is, for example, vibration of the rotor 18 of the steam turbine 3, steam temperature, steam pressure of the steam turbine 3, and a thermal expansion difference obtained by subtracting the casing axial thermal elongation from the rotor axial thermal elongation. The configuration of detecting by is preferable. Hereinafter, each detection target will be described.

(First form)
The operation state of the steam turbine 3 is preferably detected by, for example, vibration of the rotor 18 of the steam turbine 3, and the operation state detection device 44 is configured to detect vibration (vibration amplitude, vibration phase or its phase) of the rotor 18 of the steam turbine 3. The rotor vibration detection device detects both.

  The operating state detection device 44 that is a rotor vibration detection device detects rotor vibration (vibration amplitude, vibration phase or both) of the steam turbine 3, converts it into a detection signal, and inputs it to the valve control device 42.

  The valve control device 42 calculates rotor vibration based on a detection signal input from the operating state detection device 44 (rotor vibration detection device).

  When the calculated rotor vibration is larger than the preset rotor vibration, the valve control device 42 transmits a control signal for closing the electromagnetic valve 43 to the electromagnetic valve 43.

  The predetermined rotor vibration at this time may be appropriately set based on the performance of the steam turbine 3 or the like.

  The electromagnetic valve 43 is closed based on a control signal transmitted from the valve control device 42 and blocks the inflow of driving steam from the high-pressure steam supply source 45 into the pressurizing chamber 29.

  When the driving steam does not flow into the pressurizing chamber 29, the pressure receiving head 30 moves the pressure receiving head 30 in the direction opposite to the direction in which the steam pressure is pushed by the urging force of the return spring 31.

  When the pressure receiving head 30 moves in the direction opposite to the direction in which the vapor pressure is pushed, the seal substrate 25 moves in the direction opposite to the direction in which the vapor pressure is pushed. At this position, the heat-deformable spacer 28 facing the seal fins 34 on the seal substrate 25 and the seal fins 24 on the rotor 18 can come into contact with each other due to thermal deformation.

  At this time, although the free-cutting spacer 28 is dented by contact, the seal-fin 34 and the seal fin 24 are not damaged because of contact with the free-cutting spacer 28.

  Further, the valve control device 42 transmits a control signal for opening the electromagnetic valve 43 to the electromagnetic valve 43 when the calculated rotor vibration is equal to or less than a predetermined rotor vibration set in advance.

  The electromagnetic valve 43 is opened based on a control signal transmitted from the valve control device 42, and driving steam flows from the high-pressure steam supply source 45 into the pressurizing chamber 29.

  The pressure receiving head 30 moves in the direction of the pressure axis of the steam pressure by the pressure of the driving steam flowing from the high pressure steam supply source 45 into the pressurizing chamber 29.

  When the pressure receiving head 30 moves in the direction of the vapor pressure pressing axis, the seal substrate 25 moves in the direction of the vapor pressure pressing axis, and when the pressure receiving head 30 moves to a stop position in the direction of vapor pressure pressing, the seal substrate 25 is moved. The surface of the non-contact free-cutting spacer 28 on the rotor 18 side faces the seal fin 34 on the side, and the surface of the non-contact free-cutting spacer 28 on the seal substrate 25 side faces the seal fin 24 on the rotor 18 side. With this configuration, when the pressure of the steam St flowing into the pressurizing chamber 29 increases, the gap between the seal fins 34 facing each other and the free-cutting spacers 28 facing each of the seal fins 24 is set to an initial setting state. be able to. Further, the clearance between the seal fin 34 and the free-cutting spacer 28 is minimized, and the sealing performance between the stationary blade 21 and the rotor 18 is improved.

(Second form)
Further, it is preferable to detect the operation state of the steam turbine 3 based on, for example, the steam temperature of the steam turbine 3, and the operation state detection device 44 is a steam temperature detection device that detects the steam temperature of the steam turbine 3.

  The operation state detection device 44 which is a steam temperature detection device detects the steam temperature of the steam turbine 3, converts it into a detection signal, and inputs it to the valve control device 42.

  The valve control device 42 calculates the steam temperature based on the detection signal input from the operating state detection device 44 (steam temperature detection device).

  Then, the valve control device 42 transmits a control signal for closing the solenoid valve 43 to the solenoid valve 43 when the calculated steam temperature is lower than a predetermined steam temperature set in advance.

  The predetermined steam temperature at this time may be appropriately set based on the performance of the steam turbine 3 or the like.

  The electromagnetic valve 43 is closed based on a control signal transmitted from the valve control device 42 and blocks the inflow of driving steam from the high-pressure steam supply source 45 into the pressurizing chamber 29.

  When the driving steam does not flow into the pressurizing chamber 29, the pressure receiving head 30 moves the pressure receiving head 30 in the direction opposite to the direction in which the steam pressure is pushed by the urging force of the return spring 31.

  When the pressure receiving head 30 moves in the direction opposite to the direction in which the vapor pressure is pushed, the seal substrate 25 moves in the direction opposite to the direction in which the vapor pressure is pushed. At this position, the heat-deformable spacer 28 facing the seal fins 34 on the seal substrate 25 and the seal fins 24 on the rotor 18 can come into contact with each other due to thermal deformation.

  At this time, although the free-cutting spacer 28 is dented by contact, the seal-fin 34 and the seal fin 24 are not damaged because of contact with the free-cutting spacer 28.

  Further, the valve control device 42 transmits a control signal for opening the electromagnetic valve 43 to the electromagnetic valve 43 when the calculated vapor temperature is equal to or higher than a predetermined vapor temperature set in advance.

  The electromagnetic valve 43 is opened based on a control signal transmitted from the valve control device 42, and driving steam flows from the high-pressure steam supply source 45 into the pressurizing chamber 29.

  The pressure receiving head 30 moves in the direction of the pressure axis of the steam pressure by the pressure of the driving steam flowing from the high pressure steam supply source 45 into the pressurizing chamber 29.

  When the pressure receiving head 30 moves in the direction of the vapor pressure pressing axis, the seal substrate 25 moves in the direction of the vapor pressure pressing axis, and when the pressure receiving head 30 moves to a stop position in the direction of vapor pressure pressing, the seal substrate 25 is moved. The surface of the non-contact free-cutting spacer 28 on the rotor 18 side faces the seal fin 34 on the side, and the surface of the non-contact free-cutting spacer 28 on the seal substrate 25 side faces the seal fin 24 on the rotor 18 side. With this configuration, when the pressure of the steam St flowing into the pressurizing chamber 29 increases, the gap between the seal fins 34 facing each other and the free-cutting spacers 28 facing each of the seal fins 24 is set to an initial setting state. be able to. Further, the clearance between the seal fin 34 and the free-cutting spacer 28 is minimized, and the sealing performance between the stationary blade 21 and the rotor 18 is improved.

(Third form)
Moreover, the structure which detects the driving | running state of the steam turbine 3 by the pressure of the steam St may be sufficient, for example. In this case, the operation state detection device 44 is a pressure detection device that detects the pressure of the steam St.

  The operation state detection device 44 which is a pressure detection device detects the pressure of the steam St flowing through the steam turbine 3 and inputs a detection signal to the valve control device 42, and the valve control device 42 calculates the pressure of the steam St.

  The valve control device 42 transmits a control signal for closing the electromagnetic valve 43 to the electromagnetic valve 43 when the pressure of the steam St is lower than a predetermined pressure value set in advance.

  The electromagnetic valve 43 is closed based on a control signal transmitted from the valve control device 42 and blocks the inflow of driving steam from the high-pressure steam supply source 45 into the pressurizing chamber 29.

  The predetermined pressure value at this time may be appropriately set based on the performance of the steam turbine 3 or the like.

  When the driving steam does not flow into the pressurizing chamber 29, the pressure receiving head 30 moves the pressure receiving head 30 in the direction opposite to the direction in which the steam pressure is pushed by the urging force of the return spring 31.

  When the pressure receiving head 30 moves in the direction opposite to the pushing direction of the vapor pressure, the seal substrate 61 moves in the direction opposite to the pushing direction of the vapor pressure. At this position, the heat-deformable spacer 28 facing the seal fins 34 on the seal substrate 25 and the seal fins 24 on the rotor 18 can come into contact with each other due to thermal deformation.

  At this time, although the free-cutting spacer 28 is dented by contact, the seal-fin 34 and the seal fin 24 are not damaged because of contact with the free-cutting spacer 28.

  Further, the valve control device 42 transmits a control signal for opening the solenoid valve 43 to the solenoid valve 43 when the calculated steam pressure value is equal to or higher than a predetermined steam pressure value set in advance.

  The electromagnetic valve 43 is opened based on a control signal transmitted from the valve control device 42, and driving steam flows from the high-pressure steam supply source 45 into the pressurizing chamber 29.

  The pressure receiving head 30 moves in the direction of the pressure axis of the steam pressure by the pressure of the driving steam flowing from the high pressure steam supply source 45 into the pressurizing chamber 29.

  When the pressure receiving head 30 moves in the direction of the vapor pressure pressing axis, the seal substrate 25 moves in the direction of the vapor pressure pressing axis, and when the pressure receiving head 30 moves to a stop position in the direction of vapor pressure pressing, the seal substrate 25 is moved. The surface of the non-contact free-cutting spacer 28 on the rotor 18 side faces the seal fin 34 on the side, and the surface of the non-contact free-cutting spacer 28 on the seal substrate 25 side faces the seal fin 24 on the rotor 18 side. With this configuration, when the pressure of the steam St flowing into the pressurizing chamber 29 increases, the gap between the seal fins 34 facing each other and the free-cutting spacers 28 facing each of the seal fins 24 is set to an initial setting state. be able to. Further, the clearance between the seal fin 34 and the free-cutting spacer 28 is minimized, and the sealing performance between the stationary blade 21 and the rotor 18 is improved.

(4th form)
Moreover, the structure which detects the driving | running state of the steam turbine 3 by the amount of thermal expansion differences which subtracted the casing axial direction thermal elongation amount from the rotor axial direction thermal elongation amount, for example may be sufficient. In this case, the operation state detection device 44 is a thermal expansion difference detection device that detects the thermal expansion difference amount of the steam turbine.

  The operating state detection device 44 which is a thermal expansion difference detection device detects the thermal expansion difference amount of the steam turbine 3 and inputs a detection signal to the valve control device 42, and the valve control device 42 calculates the thermal expansion difference amount.

  And the valve control apparatus 42 transmits the control signal which closes the solenoid valve 43 to the solenoid valve 43, when a thermal elongation difference amount is smaller than the predetermined thermal elongation difference amount set beforehand.

  The electromagnetic valve 43 is closed based on a control signal transmitted from the valve control device 42 and blocks the inflow of driving steam from the high-pressure steam supply source 45 into the pressurizing chamber 29.

  What is necessary is just to set the predetermined amount of thermal expansion difference at this time suitably based on the performance of the steam turbine 3, etc. FIG.

  The electromagnetic valve 43 is closed based on a control signal transmitted from the valve control device 42 and blocks the inflow of driving steam from the high-pressure steam supply source 45 into the pressurizing chamber 29.

  When the driving steam does not flow into the pressurizing chamber 29, the pressure receiving head 30 moves the pressure receiving head 30 in the direction opposite to the direction in which the steam pressure is pushed by the urging force of the return spring 31.

  When the pressure receiving head 30 moves in the direction opposite to the direction in which the vapor pressure is pushed, the seal substrate 25 moves in the direction opposite to the direction in which the vapor pressure is pushed. At this position, the heat-deformable spacer 28 facing the seal fins 34 on the seal substrate 25 and the seal fins 24 on the rotor 18 can come into contact with each other due to thermal deformation.

  At this time, although the free-cutting spacer 28 is dented by contact, the seal-fin 34 and the seal fin 24 are not damaged because of contact with the free-cutting spacer 28.

  The valve control device 42 transmits a control signal for opening the electromagnetic valve 43 to the electromagnetic valve 43 when the calculated thermal expansion difference amount is equal to or larger than a predetermined thermal expansion difference amount set in advance.

  The electromagnetic valve 43 is opened based on a control signal transmitted from the valve control device 42, and driving steam flows from the high-pressure steam supply source 45 into the pressurizing chamber 29.

  The pressure receiving head 30 moves in the direction of the pressure axis of the steam pressure by the pressure of the driving steam flowing from the high pressure steam supply source 45 into the pressurizing chamber 29.

  When the pressure receiving head 30 moves in the direction of the vapor pressure pressing axis, the seal substrate 25 moves in the direction of the vapor pressure pressing axis, and when the pressure receiving head 30 moves to a stop position in the direction of vapor pressure pressing, the seal substrate 25 is moved. The surface of the non-contact free-cutting spacer 28 on the rotor 18 side faces the seal fin 34 on the side, and the surface of the non-contact free-cutting spacer 28 on the seal substrate 25 side faces the seal fin 24 on the rotor 18 side. With this configuration, when the pressure of the steam St flowing into the pressurizing chamber 29 increases, the gap between the seal fins 34 facing each other and the free-cutting spacers 28 facing each of the seal fins 24 is set to an initial setting state. be able to. Further, the clearance between the seal fin 34 and the free-cutting spacer 28 is minimized, and the sealing performance between the stationary blade 21 and the rotor 18 is improved.

In the description of FIG. 9, an example of one detection item has been described for the operation state detection example of the operation state detection device 44. However, a configuration in which a plurality of items are detected at the same time is possible.
For example, the steam temperature and the steam pressure are detected as the operation state, and the pressure receiving head 30 is moved in the direction of the steam pressure only when both values are equal to or higher than a predetermined steam temperature and a predetermined steam pressure. Can do. None of these differ from the essence of the present invention.

  As the free-cutting spacer 28, a free-cutting spacer 28 using a breathable metal can be used. By using the free-cutting spacer 28 using a breathable metal, not only can the seal fin 34 and the seal fin 24 be prevented from being damaged, but also the contact caused by the contact between the seal fin 34 and the seal fin 24 and the free-cutting spacer 28. Heat generation can be removed and thermal deformation due to contact heat generation can be prevented.

  Further, the labyrinth seal device 23 and the driving steam shown in FIG. 9 are configured to flow into the pressurizing chamber 29 from the high-pressure steam supply source 45 and move the pressure-receiving head 30 in the direction. The structure which moves 30 to a direction may be sufficient.

  Further, the seal structure incorporated between the nozzle diaphragm outer ring 20 and the moving blade 17 may be the same as the seal structure shown in FIG.

  As described above, the steam turbine 3 according to the present embodiment, as shown in FIG. A seal structure including the seal fin 24 and the free-cutting spacer 28 on the seal substrate side 25 is incorporated. The sealing substrate 25 provided with the free-cutting spacer 28 is provided so as to be movable in the axial direction of the rotor 18.

With this configuration, when the load on the steam turbine 3 increases, the pressure receiving head 30 moves in the direction of the steam load pressure axis of the rotor 18, and the seal substrate 25 connected to the pressure receiving head 30 moves in the direction of the steam load pressure axis. To do. Since the free-cutting spacer 28 at the position facing the position of the seal fin 24 after the movement is kept in a non-contact state, the clearance between the seal fin 24 and the free-cutting spacer 28 becomes the minimum state, and the stationary blade The sealing performance between 21 and the rotor 18 is improved.
Therefore, the sealing performance between the stationary blade 21 and the rotor 18 is improved, and an excellent effect is achieved in that a decrease in turbine efficiency due to leaked steam can be suppressed.

  Further, the free-cutting spacer 28 is formed of a free-cutting metal that is an abradable material having excellent machinability. With this configuration, even if the seal fins 34 and 24 and the free-cutting spacer 28 come into contact with each other, the free-cutting spacer 28 is cut so that the seal fin 34 and the seal fin 24 can be prevented from being damaged. Play.

  For example, the seal structure including the labyrinth seal device 23, the seal fin 24, and the free-cutting spacer 28 shown in FIG. 3 is not limited between the nozzle diaphragm inner ring side 22 and the rotor 18, but the casing 19 (FIG. 2) and the rotor 18, and can be incorporated between other fixed parts and rotating parts.

DESCRIPTION OF SYMBOLS 1 Power plant 3 Steam turbine 6 Rotor 17 Rotor blade 19 Casing 21 Stator blade 23 Labyrinth seal device 24, 34, 40 Seal fin 25 Seal substrate 26, 35 High part 27, 36 Low part 28 Free-cutting spacer 29 Pressurizing chamber ( Drive unit)
30 Pressure receiving head (movable part)
31 Return spring (biasing means)
32 Guide 33, 41 Guide receiver 39 Cover 42 Valve control device (drive device)
43 Solenoid valve (drive device)
44 Operating state detection device 45 High-pressure steam supply source (drive device)
46 Steam passage St Steam

Claims (16)

A rotating part composed of a rotor and a member that rotates integrally with the rotor;
Incorporated in a steam turbine having a casing containing the rotating part and a fixing part made of a member fixed to the casing;
Seal fins provided on both or one of the rotating part and the fixed part;
A seal structure of a steam turbine having a spacer using a free-cutting metal provided on the rotating part or the fixed part facing the seal fin,
In the case where the fixed portion is provided with the seal fin, the seal fin provided in the fixed portion by a driving device is movable in the rotor axial direction with respect to the rotating portion,
In the case where the fixed portion is provided with the spacer, the spacer provided in the fixed portion by the driving device is movable in the rotor axial direction with respect to the rotating portion. As the driving device,
The fixed portion has a movable portion that moves in the axial direction of the rotor by the pressure of the steam flowing through the steam turbine, and that is movable by being biased in a direction opposite to the direction in which the steam pressure acts by the biasing means. With
When the fixed portion is provided with the seal fin, the seal fin provided in the fixed portion is attached to the movable portion,
When the fixed portion is provided with the spacer, the spacer provided in the fixed portion is attached to the movable portion,
When the pressure of the steam moves the movable part in the rotor axial direction is smaller than the urging force by which the urging means urges the movable part in the opposite direction, the seal fins facing each other And the spacer are in contact with each other,
2. The steam according to claim 1, wherein when the pressing force becomes equal to or greater than the urging force, the movable portion moves to a position where a gap between the seal fin and the spacer facing each other becomes a predetermined set value. Turbine seal structure. As the driving device,
The movable portion includes a seal base to which the seal fin or the spacer is fixed, a pressure receiving head portion to which the seal base is fixed and receiving the pressing force, and a guide portion provided in the pressure receiving head,
The fixed portion includes a pressure chamber that holds the pressure receiving head portion therein, a guide receiver that is provided in the pressure chamber, supports the guide portion, and guides the movement of the pressure receiving head portion in the rotor axial direction; 3. The steam passage according to claim 2, further comprising: a steam flow path that communicates with the pressurizing chamber and guides the steam that flows through the steam turbine to the pressurizing chamber; and a spring that applies a biasing force to the pressure receiving head. Steam turbine seal structure. As the driving device,
The fixed portion includes a movable portion that moves in the axial direction of the rotor by the pressure of the steam and is movable by being biased in a direction opposite to the direction of the action of the steam pressure by the biasing means. When the seal fin is provided, the seal fin provided in the fixed portion is attached to the movable portion,
When the fixed part is provided with the spacer, the spacer provided in the fixed part is attached to the movable part,
A valve that is provided in the flow path of the steam that moves the movable part, and controls the supply amount of the steam;
An operation state detection device for detecting an operation state of the steam turbine;
A control device that controls the opening of the valve by a signal from the operating state detection device and controls the amount of movement of the movable part;
When the pressure of the steam moves the movable part in the rotor axial direction is smaller than the urging force by which the urging means urges the movable part in the opposite direction, the seal fins facing each other And the spacer are in contact with each other,
2. The steam according to claim 1, wherein when the pressing force becomes equal to or greater than the urging force, the movable portion moves to a position where a gap between the seal fin and the spacer facing each other becomes a predetermined set value. Turbine seal structure. The operation state detection device is a rotor vibration detection device that detects vibration of the rotor, and detects an operation state of the steam turbine by vibration of the rotor,
The control device, when the rotor vibration is equal to or less than a predetermined vibration value, moves the movable portion to a rotor axial position where a gap between the seal fin and the spacer becomes a predetermined set value. Item 5. A steam turbine seal structure according to Item 4. The operation state detection device is a temperature detection device that detects the temperature of the steam, detects the operation state of the steam turbine based on the temperature of the steam,
The control device moves the movable part to a rotor axial position where a gap between the seal fin and the spacer becomes a predetermined set value when the temperature of the steam is equal to or higher than a predetermined temperature value. The steam turbine seal structure according to claim 4. The operating state detecting device is a pressure detecting device that detects the pressure of the steam, and detects the operating state of the steam turbine based on the pressure of the steam,
The control device moves the movable part to a rotor axial direction position where a clearance between the seal fin and the spacer becomes a predetermined set value when the pressure of the steam is equal to or higher than a predetermined pressure value. The steam turbine seal structure according to claim 4. The operating state detection device is a thermal elongation difference detection device that detects a difference in thermal expansion between the rotor and the casing in the axial direction, and detects an operating state of the steam turbine based on the difference in thermal elongation.
The control device moves the movable part to a rotor axial position where a gap between the seal fin and the spacer becomes a predetermined set value when the difference in thermal expansion is equal to or greater than a predetermined difference in thermal expansion. The seal structure for a steam turbine according to claim 4. The movable portion includes a seal ring portion to which the seal fin or the spacer is fixed, a pressure receiving head portion to which the seal ring is fixed and receiving the pressing force, and a guide portion provided in the pressure receiving head,
The fixed portion includes a pressure chamber that holds the pressure receiving head therein, a guide receiver that is provided in the pressure chamber, supports the guide portion of the pressure receiving head, and guides the axial movement of the pressure receiving head. A steam passage that communicates with the pressurizing chamber, guides the steam to the pressurizing chamber, and a spring that applies a biasing force to the pressure receiving head,
The steam turbine seal structure according to any one of claims 4 to 8, wherein the valve is provided in the steam flow path.   The steam turbine seal structure according to any one of claims 1 to 9, wherein the free-cutting metal is a breathable metal. A rotating part composed of a rotor and a member that rotates integrally with the rotor;
Incorporated in a steam turbine having a casing containing the rotating part and a fixing part made of a member fixed to the casing;
Seal fins provided on both or any one of the rotating part and the fixing part, spacers using free-cutting metal provided on the rotating part or the fixing part facing the seal fin, and the fixing And a movable part that is movable by a drive device,
When the fixed portion is provided with the seal fin, the seal fin provided in the fixed portion is attached to the movable portion,
When the fixed part is provided with the spacer, the spacer provided in the fixed part is a control method of a seal structure attached to the movable part,
Along with the steady load operation of the steam turbine, the moving part is moved in the rotor axial direction, and a procedure for moving the movable part to a position where a gap between the seal fin and the spacer facing each other becomes a predetermined set value is provided. A control method of the seal structure which is characterized. Detecting the vibration of the rotor;
A step of moving the movable part to a position in the rotor axial direction where a gap between the seal fin and the spacer becomes a predetermined set value when the vibration of the rotor is equal to or less than the vibration of the predetermined rotor. The method for controlling a seal structure according to claim 11. Detecting the temperature of the steam;
A step of moving the movable part to a position in the rotor axial direction where a gap between the seal fin and the spacer becomes a predetermined set value when the steam temperature is equal to or higher than a predetermined steam temperature. The method for controlling a seal structure according to claim 11. Detecting a pressure of steam flowing through the steam turbine;
And a step of moving the movable part to a rotor axial position where a gap between the seal fin and the spacer becomes a predetermined set value when the steam pressure is equal to or higher than a predetermined pressure value. The method for controlling a seal structure according to claim 11. Detecting a difference in axial thermal expansion between the rotor and the casing;
A step of moving the movable part to a position in the rotor axial direction where a gap between the seal fin and the spacer becomes a predetermined set value when the difference in thermal expansion is equal to or greater than a predetermined difference in thermal elongation. The method for controlling a seal structure according to claim 11.   The method for controlling a seal structure according to any one of claims 11 to 15, wherein the free-cutting metal is a breathable metal.

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