JP2008297980A - Shaft seal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft seal device stabilized in the flow of the main flow and further improved in heat efficiency by preventing leaked vapor from flowing out and in. <P>SOLUTION: This shaft seal device is provided with a moving blade tip upstream side vapor leak inhibition part 33 preventing a leak of working vapor in a gap between the upstream side tip of a shroud 29 and a diaphragm outer ring 24, and a moving blade root downstream side vapor leak inhibition part 34 preventing a leak of working vapor in a gap between the downstream side of a turbine disk 26 having the turbine moving blade 27 implanted thereon and a diaphragm inner ring 25 supporting an adjoining turbine nozzle 23. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is used in fluid machines such as a steam turbine, a gas turbine, and an air compressor, and effectively suppresses the working fluid from leaking out of the working fluid passage through the gap between the stationary part and the rotating part during operation. The present invention relates to a shaft seal device.

  For example, in a steam turbine, a stationary part such as a turbine nozzle and a rotating part such as a turbine blade are combined, and the speed energy of the fluid ejected from the turbine nozzle or the like is used to rotate the turbine blade and the like. For example, a driven machine such as a generator is driven by the generated power (rotational torque).

  In a steam turbine having such a configuration, the rotating part has a smaller mass than the stationary part, so that the heat capacity is small and the heat transfer when it is rotating with respect to temperature changes during start-up, stop, and load interruption. Since the rate is large, it expands and contracts sensitively, so the stationary part expands and contracts behind the rotating part.

  For this reason, the stationary part and the rotating part may come into contact during thermal expansion and contraction.To avoid this contact, the difference in elongation between the rotating part and the stationary part is calculated, and a margin based on experience is added to the calculated value. In addition, a gap between the stationary part and the rotating part has been set.

  That is, if the gap between the stationary part and the rotating part is large, the working fluid leaks out of the working fluid passage, and the generation of power does not contribute, resulting in a decrease in thermal efficiency. On the other hand, if the gap is reduced, the leakage of the working fluid to the outside of the passage is reduced and the heat is effectively utilized to increase the thermal efficiency, but there is a concern of a contact accident.

  Considering such an event, a gap between the stationary part and the rotating part is set, and there is a structure shown in FIG.

  FIG. 14 is a longitudinal sectional view of a turbine stage in which a part of the steam turbine is extracted.

  Of the turbine stage 11 in which the turbine nozzle 3 disposed on the upstream side and the turbine blade 5 disposed on the downstream side are combined along the flow of the main flow (working steam) 4, the turbine nozzle 3 has the turbine blade on the outer peripheral side. A stationary portion 12 is supported and fixed by a diaphragm outer ring 1 extending to 5 and is supported and fixed in an annular row along the circumferential direction of the diaphragm inner ring 2 on the inner peripheral side.

  Further, the turbine rotor blade 5 includes a shroud 6 facing the labyrinth fin 9 fixed to the diaphragm outer ring 1 on the tip side, and a turbine disk formed and processed integrally with a turbine rotor (not shown) on the root side. The rotating part 13 is planted in an annular row along the circumferential direction.

  During operation, the main flow 4 that obtains velocity energy at the turbine nozzle 3 and turns the flow rotates the turbine blades 5 and generates power (rotational torque).

  Most of the main flow 4 to which turning force is applied from the turbine nozzle 3 flows along the blade surface of the turbine rotor blade 5, but a part of the main flow 4 becomes leakage steam 7 and flows through the gap between the labyrinth fin 9 and the shroud 6. In some cases, the flow was disturbed by the leaked steam 8 flowing out from the gap between the diaphragm inner ring 2 and the turbine disk 10. The partial leakage of the main flow 4 and the turbulence of the flow of the main flow 4 due to the inflow of the leaked steam are part of the factors of the reduction in the thermal efficiency of the steam turbine.

On the other hand, in consideration of thermal expansion during operation, the turbine rotor blade 5 is, when assembled, the rotor blade upstream clearance dimension C1 between the shroud 6 and the diaphragm outer ring 1 and the diaphragm inner ring 2 adjacent to the turbine disk 10 (downstream side). each of the moving blade downstream gap dimension C ₂ and were set as follows.

The moving blade upstream side clearance dimension C ₁ is calculated by calculating the dimension of the position where the turbine moving blade 5 is closest to the upstream turbine nozzle 3 at the time of starting, stopping, or when the load is interrupted, as indicated by a broken line. It was set as (D ₁ + M ₁ ) obtained by adding a margin value M ₁ based on experience to the elongation dimension D ₁ as a predicted value.

Further, the moving blade downstream side clearance dimension C ₂ is the dimension at which the turbine moving blade 5 is closest to the downstream diaphragm inner ring 2 as shown by a two-dot chain line at the time of starting, stopping, or load interruption. The margin value M ₂ based on experience is added to the elongation dimension D ₂ that is the predicted value calculated by calculation, and is set as (D ₂ + M ₂ ).

As described above, the conventional steam turbine is set by adding the margin values M ₁ and M _{2 to} the moving blade upstream clearance C ₁ and the moving blade downstream clearance C ₂ of the turbine moving blade 5. In addition, it was possible to prevent the leakage of the steam 7 from the gap between the diaphragm outer ring 1 and the shroud 6 and to prevent the thermal efficiency from being lowered due to the disturbance of the main flow 4 caused by the leaked steam 8 flowing out from the gap between the diaphragm inner ring 2 and the turbine disk 10. .

As a technique for reducing the amount of steam leaking from the gap between the labyrinth fin and the shroud on the tip side of the turbine rotor blade, for example, as described in Patent Document 1, a diaphragm outer ring located on the upstream side of the shroud Protrusions are formed on the cylindrical ring provided on the surface, and the diameter of the tip of the protrusion is set large so as not to contact the shroud. For example, as described in Patent Document 2, a notch is provided in the shroud facing the labyrinth fin. In this proposal, the notch is made shallower as it goes in the direction of rotation, and vortexes are generated in the leaked steam flowing along the notch to prevent the leaked steam from being blown out.
Japanese Patent Publication No. 4-35601 JP 2001-32948 A

The shaft seal device applied to the steam turbine shown in FIG. 14 has margin values M ₁ and M when setting the moving blade upstream gap size C ₁ and the moving blade downstream clearance size C ₂ of the turbine moving blade. Each of ₂ is added, but the judgment of these margin values M ₁ and M ₂ is left to experience.

However, since the margin values M ₁ and M ₂ are based on experience and may not be the optimum values, in the conventional shaft seal device, the leakage steam 7 blows out from the gap between the diaphragm outer ring 1 and the shroud 6, Or, there was some concern, such as a decrease in thermal efficiency due to the disturbance of the main flow 4 due to the leaked steam 8 flowing out from the gap between the diaphragm inner ring 2 and the turbine disk 10.

  The present invention has been made based on such a situation, and when setting the moving blade upstream side clearance dimension and the moving blade downstream side clearance dimension of the turbine rotor blade, the inflow and outflow of the leaked steam can be performed without adding a margin value. An object of the present invention is to provide a shaft seal device that further stabilizes the mainstream flow and further improves the thermal efficiency.

  In order to achieve the above-described object, the present invention provides a stationary portion that sandwiches an outer peripheral side and an inner peripheral side of a turbine nozzle between a diaphragm outer ring and a diaphragm inner ring, and a turbine rotor blade positioned downstream of the turbine nozzle. A shaft seal device provided with a labyrinth fin provided on the outer ring of the diaphragm, and provided on a front end side of the turbine rotor blade. A turbine blade adjacent to the downstream side of the turbine disk on which the turbine rotor blade is implanted, and a turbine blade tip upstream steam leakage suppression portion for preventing leakage of working steam in a gap between the side tip and the diaphragm outer ring A moving blade root portion downstream side steam leakage suppressing portion for preventing leakage of working steam is provided in a gap with the supporting inner ring of the diaphragm.

  Further, in order to achieve the above-mentioned object, the present invention provides a rotor blade upstream side steam leakage suppressing portion for a shroud piece protruding from the upstream end of the shroud and a diaphragm outer ring provided on the diaphragm outer ring. And further comprising a seal fin provided on the downstream side of the turbine disk and a diaphragm inner ring free cutting part provided on an adjacent diaphragm inner ring. It consists of.

  Further, in order to achieve the above-described object, the present invention can make the container tip upstream side steam leakage suppression portion detachable from the diaphragm outer ring with respect to the diaphragm outer ring. Further, the moving blade tip upstream steam leakage suppression portion is provided in a storage container for storing the diaphragm outer ring free cutting portion, and a piston sliding in a space chamber formed in the diaphragm outer ring, And a spring that applies a pressing force to the piston.

  In the present invention, in order to achieve the above-mentioned object, the piston has a protruding portion at the tip.

  In order to achieve the above-described object, the present invention provides that the steam blade tip upstream side steam leakage suppression portion is discretely arranged along the circumferential direction on the free cutting portion for the diaphragm outer ring accommodated in the accommodating container. Further, the moving blade tip upstream steam leakage suppression portion is provided with a circumferential groove along the circumferential direction in the diaphragm outer ring free cutting portion accommodated in the accommodating container. Is.

  In the present invention, in order to achieve the above-mentioned object, the circumferential groove includes a flat side extending inward from the surface of the free-cutting portion for the diaphragm outer ring, and the diaphragm outer ring cover from an end of the side. It is comprised with the inclined side formed in the inclined shape which faces the surface of a free-cutting part.

  In order to achieve the above-mentioned object, the present invention provides the above-described moving blade tip upstream steam leakage suppression portion, in which a free-cutting portion for a diaphragm outer ring is provided with a radial groove along the radial direction, Further, the radial groove has a flat side extending from the surface of the diaphragm outer ring free-cutting portion at a right angle toward the inside, and an inclined shape extending from an end of the side toward the surface of the diaphragm outer ring free-cutting portion. And the inclined side to be formed.

  In the present invention, in order to achieve the above-mentioned object, the radial groove is provided along a radial line passing through the center of the turbine rotor, and further, the radial groove has a rotational direction of the turbine rotor. It is configured to be inclined in the reverse direction and with respect to the radial line.

  In order to achieve the above-mentioned object, the present invention provides the steam blade tip upstream side steam leakage suppression portion in which a circumferential groove and a radial groove are combined in a free cutting portion for a diaphragm outer ring. is there.

  In order to achieve the above-mentioned object, the free-cutting portion for the diaphragm outer ring is made of any member of Ni, Cr, Al, bentonite and Ni, Cr, Fe, Al, boron nitride. On the other hand, the free-cutting portion for the inner ring of the diaphragm is a member selected from Ni, Cr, Al, bentonite, Ni, Cr, Fe, Al, and boron nitride.

  In order to achieve the above-mentioned object, the present invention applies any one of claims 1 to 16 to a steam turbine.

  The shaft seal device according to the present invention includes a rotor blade in a gap between the upstream side of the tip of the turbine blade and the diaphragm outer ring and a gap between the downstream side of the turbine blade and the turbine nozzle adjacent to and supporting the adjacent turbine nozzle. Since each of the tip upstream steam leakage suppression part and the rotor blade root downstream steam leakage suppression part is provided, leakage of working steam to the outside of the passage can be further prevented, and the mainstream thermal energy is effective. Can be used.

  An embodiment of a shaft seal device according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a longitudinal sectional view showing a first embodiment of a shaft seal device according to the present invention, which is incorporated in an exemplary steam turbine and extracted from a part thereof.

  The steam turbine is roughly divided and includes stationary portions 21 and rotating portions 22 that are alternately arranged along the flow of the main flow (working steam) 31.

  The stationary portion 21 includes a turbine nozzle 23 arranged in an annular row along a circumferential direction of a turbine rotor (rotating shaft) (not shown), and an outer peripheral side and an inner peripheral portion side of the turbine nozzle 23 arranged in an annular row. A diaphragm outer ring 24 and a diaphragm inner ring 25 are provided which are sandwiched and fixedly supported. The diaphragm outer ring 24 is fixedly supported by a turbine casing (not shown).

  The rotating portion 22 is provided on the turbine rotor blade 27 planted in an annular row on a turbine disk 26 molded integrally with the turbine rotor, and on the tip side of the turbine rotor blade 27 arranged in the annular row. A shroud 29 facing a labyrinth fin 28 fixed to and supported by a diaphragm outer ring 24 extending from the nozzle 23 is provided.

  In the steam turbine having such a configuration, the turbine nozzle 23 of the stationary part 21 and the turbine rotor blades 27 of the rotating part 22 are combined to form a turbine stage 30, and a plurality of turbine stages 30 are arranged in the axial direction. The main flow (working steam) 31 flowing through 30 is caused to perform expansion work, and the power generated at that time is taken out.

  On the other hand, when the power is extracted, most of the main flow 31 exiting the turbine nozzle 23 flows along the blade surface of the turbine rotor blade 27 and turns, and is guided to the next (downstream) turbine stage. However, a part thereof is affected by the centrifugal force and flows as a leaked steam 32 a through a gap between the shroud 29 of the turbine rotor blade 27 and the labyrinth fin 28 of the diaphragm outer ring 24.

  The leaked steam 32 b flowing out from the gap between the diaphragm inner ring 25 that fixes and supports the turbine nozzle 23 and the turbine disk 26 that supports the turbine rotor blade 27 flows in the main flow 31 that flows through the bottom (base) of the turbine rotor blade 27. Then, the gas again flows into the gap between the turbine disk 26 on the downstream side and the diaphragm inner ring 25 in the next paragraph.

  Since these leaked steams 32a and 32b do not contribute to the expansion work, they have been one of the causes of a decrease in thermal efficiency.

Further, since the steam turbine uses, for example, a mainstream 31 having a high pressure and a high temperature of 250 kg / cm ² and 538 ° C. as the working steam, expansion and contraction due to heat occurs. In particular, at the time of starting, stopping or shutting off the load, the turbine rotor blade 27 is moved to the upstream turbine nozzle 23 side as indicated by a broken line, or is indicated by a two-dot chain line, as shown by a broken line. It is remarkable that it moves to a downstream turbine nozzle (not shown). Due to the movement at this time, a contact accident may occur between the shroud 29 and the diaphragm outer ring 24.

  The shaft seal device according to the present embodiment is made to cope with such an event, and as shown in FIG. 1, faces the upstream side of the shroud 29 provided on the tip side of the turbine rotor blade 27. The tip of the turbine disk 26 is provided on the side facing the diaphragm outer ring 24 that supports and fixes the turbine nozzle 23, and the turbine blade 26 upstream side steam leakage suppression part 33 is provided, and the turbine disk 26 that supports the root side of the turbine rotor blade 27 is provided. A turbine blade 26 facing the diaphragm inner ring 25 that supports and fixes the adjacent turbine nozzle on the downstream side and the turbine disk 26 facing the adjacent diaphragm inner ring 25 is provided with a steam blade downstream downstream steam leakage suppressing portion 34.

  As shown in FIG. 2, the moving blade tip upstream side steam leakage suppression portion 33 includes a protruding shroud piece 35 provided on the upstream tip portion of the shroud 29 and on the side facing the diaphragm outer ring 24, and the protruding shroud piece 35. The diaphragm outer ring free-cutting portion (abradable member) 36 provided on the diaphragm outer ring 24 facing the front.

  Further, as shown in FIG. 3, the moving blade root downstream side steam leakage suppression unit 34 is provided between the downstream side of the turbine disk 26 that supports the turbine moving blade 27 and the diaphragm inner ring 25 that supports and fixes the adjacent turbine nozzle. And a seal fin 37 provided on the downstream side of the turbine disk 26 and a diaphragm inner ring free cutting portion 38 provided on the diaphragm inner ring 25 facing and adjacent to the seal fin 37.

  Each of the diaphragm outer ring free cutting part 36 and the diaphragm inner ring free cutting part 38 provided as the moving blade tip upstream steam leakage suppression part 33 and the rotor blade root downstream steam leakage suppression part 34 is both , Ni, Cr, Al, bentonite and Ni, Cr, Al, and each of the shroud pieces 35 and the seal fins 37 projecting toward the upstream side of the shroud 29 is broken or double-pointed from the position of the solid line by the heat of steam. When moving, contacting, and biting into the position indicated by the chain line, it is made of a member having high machinability that forms the recesses 39a and 39b without breaking or wearing.

  In the shaft seal device having such a configuration, when starting, stopping, or when the load is interrupted, the main flow 31 is stretched by heat, and the turbine rotor blade 27 is directed toward, for example, the upstream turbine nozzle 23 in FIG. As shown in FIG. 4, when the movable shroud 35 moves from the position indicated by the solid line to the position indicated by the broken line, the protruding shroud piece 35 contacts and advances the diaphragm outer ring free-cutting portion 36 and wears the diaphragm outer ring free-cutting portion 36. Eventually, the recess 39a is formed.

  When the protruding shroud piece 35 is in contact with the free-cutting portion 36 for the diaphragm outer ring. Since the gap between the shroud 29 of the turbine blade 27 and the diaphragm outer ring 24 is closed, the flow of the leaked steam 32a is sealed.

  When the turbine rotor blade 27 enters steady operation (rated operation) and the temperature difference from the mainstream 31 decreases and stabilizes, the projecting shroud piece 35 is subjected to a diaphragm outer ring cover as shown in FIG. It leaves | separates from the free-cutting part 36 and leaves the recessed part 39a.

  In this case, the leaked steam 32a tries to blow through toward the labyrinth fin 28 from the gap between the shroud piece 35 protruding toward the upstream side of the shroud 29 and the free cut portion 36 for the diaphragm outer ring, but collides with the recess 39a. The flow is blocked by the flow of vortices generated during the process.

  On the other hand, at the time of startup or the like, the heat flow of the main flow 31 occurs, and the turbine rotor blade 27 is indicated by a two-dot chain line from the position of the solid line as shown in FIG. 3, for example, toward the diaphragm inner ring 25 side on the downstream side. When moving to the position, the seal fin 37 advances in contact with the diaphragm inner ring free-cutting portion 39, wears the diaphragm inner ring free-cutting portion 39, and a recess 39b is formed.

  When the seal fin 37 is in contact with the diaphragm inner ring free cutting portion 39, the flow of the leaked steam 32b is sealed in the same manner as described above, and the steady operation is started. As shown in FIG. When the recess 39b is formed in the free-cutting portion 39, the flow of the leaked steam 32b is blocked by the vortex flow generated from the recess 39b.

  As described above, in the present embodiment, the steam blade tip upstream side steam leakage suppression portion 33 is provided in the gap between the shroud 29 of the turbine rotor blade 27 and the diaphragm outer ring 24, and the root portion side of the turbine rotor blade 27 is disposed on the root side. A moving blade root downstream steam leakage suppressing portion 34 is provided in a gap between the turbine disk 26 to be supported and the diaphragm inner ring 25 adjacent to the next (downstream side), and the size of each gap is narrower without including a margin. Since the configuration can be set to a value, it is possible to further reduce the leakage of the main flow 31 from the shroud 29 side of the turbine blade 27 to the shroud 29 side, and from the upstream side of the blade root portion of the turbine blade 27. The unstable flow of the main flow 31 based on the leaked steam 32b that flows in can be further reduced.

  Further, the present embodiment includes a diaphragm outer ring free-cutting portion 36 as the moving blade tip upstream steam leakage suppressing portion 33 and a diaphragm inner ring free-cutting portion as the moving blade root downstream downstream steam leakage suppressing portion 34. 38, the shroud piece 35 protruding upstream from the shroud 29 contacts the diaphragm outer ring 24, or even if the seal fin 37 of the turbine disk 26 contacts the adjacent diaphragm inner ring 25, The cutting portions 36 and 38 absorb the impact force and the like, and do not cause breakage or wear.

  Therefore, according to the present embodiment, coupled with increasing the work efficiency of the mainstream 31 and improving the thermal efficiency, it is possible to perform a stable operation with few accidents such as breakage for a long time.

  FIG. 4 is a longitudinal sectional view showing a second embodiment of the shaft sealing device according to the present invention.

  In addition, the same code | symbol is attached | subjected to the same structure as the structure of 1st Embodiment, or a corresponding part, and duplication description is abbreviate | omitted.

  In the shaft seal device according to the present embodiment, the steam blade tip upstream side steam leakage suppression portion 33 provided between the upstream side of the shroud 29 provided on the tip side of the turbine rotor blade 27 and the diaphragm outer ring 24 is provided with a diaphragm outer ring. 24 is configured to be detachable.

  The moving blade tip upstream side steam leakage suppression portion 33 accommodates a housing container 40 having an open side on the three side surfaces, and the diaphragm outer ring free-cutting portion 36 in the housing container 40, and against the diaphragm outer ring 24, It is provided with a connection tool 41 such as a bolt that is detachable.

  As described above, in the present embodiment, the moving blade tip upstream steam leakage suppression portion 33 is configured as a three-sided opening-shaped storage container 40 for storing the diaphragm outer ring free-cutting portion 36, and the storage container 40 is Since it is configured to be detachable with respect to the diaphragm outer ring 24, the thermal spraying work of the free-cutting member can be easily performed from any position by removing the container 40 from the diaphragm outer ring 24, and the workability in manufacturing. Further, the maintenance work can be easily performed even if the concave portion 39a formed in the diaphragm outer ring free cut portion 36 becomes too large to be replaced.

  In the present embodiment, the moving blade tip upstream steam leakage suppressing portion 33 is configured as a three-sided opening-shaped storage container 40 for storing the diaphragm outer ring free-cutting portion 36, and the storage container 40 is configured as the diaphragm outer ring 24. However, the present invention is not limited to this example. For example, as shown in FIG. 5 of the third embodiment, the piston 43 having a protruding portion 42 on the closed surface of the storage container 40 is provided. And a spring 45 that applies a pressing force using elastic force when the piston 43 slides in the space 44 provided in the diaphragm outer ring 24.

  In the present embodiment, since the piston 43 is pressed using the elastic force of the spring 45, the shroud piece 35 protruding toward the upstream side from the shroud 29 comes into contact with the free cutting portion 36 for the diaphragm outer ring and advances. However, the impact can be reduced and damage can be suppressed. Furthermore, even if the shroud piece 35 protruding upstream from the shroud 29 is about to be separated from the free cutting portion 36 for the diaphragm outer ring, the gap is further reduced. Further, it is possible to reduce the leakage of the leaked steam 32a and to further effectively use the heat energy of the main stream 31.

  FIG. 6 is a longitudinal sectional view showing a fourth embodiment of the shaft seal device according to the present invention.

  In addition, the same code | symbol is attached | subjected to the same structure as the structure of 1st Embodiment, or a corresponding part, and duplication description is abbreviate | omitted.

  The shaft seal device according to the present embodiment includes indentations discretely arranged in a diaphragm outer ring free cutting portion 36 housed in a three-side-opening containing container 40 as a moving blade tip upstream steam leakage suppression portion 33. 46 is provided.

  When the recess 46 is provided in the diaphragm outer ring free-cutting portion 36, the leaked steam 32a attempting to pass through the moving blade top upstream steam leakage suppressing portion 33 is shroud pieces protruding from the shroud 29 toward the upstream side (see FIG. A vortex is generated by colliding with the concave portion 39a formed by (not shown), and a vortex is also generated in the recess 46, and a large number of vortices are generated.

  As described above, in this embodiment, since the hollow 46 for generating a large number of vortices in the leaked steam 32a that attempts to pass through the upstream-side steam leak suppressing part 33 of the rotor blade is provided in the free cutting part 36 for the diaphragm outer ring. A large number of vortices can serve as barriers to reduce leakage of the leaked steam 32a, and further effective utilization of the heat energy of the mainstream 31 can be achieved.

  FIG. 7 is a longitudinal sectional view showing a fifth embodiment of the shaft seal device according to the present invention.

  In addition, the same code | symbol is attached | subjected to the same structure as the structure of 1st Embodiment, or a corresponding part, and duplication description is abbreviate | omitted.

  The shaft seal device according to the present embodiment has a diaphragm outer ring free cutting portion 36 housed in a three-side-opening containing container 40 as a moving blade tip upstream steam leakage suppressing portion 33 along the circumferential direction thereof. A circumferential groove 47 is provided.

  As shown in FIG. 8, the circumferential groove 47 includes a flat side 49 extending inward at a right angle to the end edge (surface) 48 of the diaphragm outer ring free-cutting portion 36, and an end of the side 49. And an oblique side 50 extending in an inclined manner from the section toward the edge (surface) 48, and when the leaked steam 32a passes through this, the radial inner peripheral side passing through the center of the turbine rotor (not shown). A vortex is generated by flowing along the inclined side 50 and eventually colliding with the flat side 49, and the flow of the leaked steam 32a is stopped by the generated vortex.

  As described above, in this embodiment, the flat outer edge 49 and the inclined edge 50 provided along the circumferential direction of the diaphragm outer ring free-cutting portion 36 as the moving blade tip upstream steam leakage suppressing portion 33. And the leakage steam 32a flowing along the inclined side 50 is caused to collide with the side 49 to generate a vortex, and the flow of the leakage steam 32a is blocked by the generated vortex. Leakage of the leaked steam 32a can be reduced, and more effective utilization of the heat energy of the mainstream 31 can be achieved.

  FIG. 9 is a longitudinal sectional view showing a sixth embodiment of the shaft seal device according to the present invention.

  In addition, the same code | symbol is attached | subjected to the same structure as the structure of 1st Embodiment, or a corresponding part, and duplication description is abbreviate | omitted.

  The shaft seal device according to the present embodiment is provided with a radial groove 51 in the diaphragm outer ring free-cutting portion 36 housed in the three-side-opening containing container 40 as the moving blade tip upstream steam leakage suppressing portion 33. It is a thing.

  As shown in FIG. 10, the radial groove 51 includes a flat side 49 extending inward at a right angle to the end edge (surface) 48 of the diaphragm outer ring free cut portion 36, and an end of the side 49. And an inclined side 50 extending in an inclined manner from the portion toward the edge (surface).

  Further, as shown in FIG. 11, the radial groove 51 is formed in an annular row along the radial line RL in which the edge of the side 49 passes through the center O of the turbine rotor 52 and along the rotational direction R of the turbine rotor 52. Is provided.

  As shown in FIG. 9, the radial groove 51 having such a configuration causes a collision at the side 49 when the leaked steam 32 a accompanied by the swirling flow flows along the inclined side 50, thereby reducing the swirling speed component. Instead, the radial velocity component is increased to cause more collision with a labyrinth fin (not shown), and the flow is stopped.

  Thus, in this embodiment, the flat side 49 and the inclined side 50 provided along the radial direction of the free-cutting portion 36 for the diaphragm outer ring as the upstream-side steam leakage suppression portion 33 of the rotor blade tip. And the leaked steam 32a accompanied by the swirling flow flowing along the inclined side 50 is caused to collide with the side 49, the swirling speed component is decreased and the radial speed component is increased, and the labyrinth fin is more collided. Thus, since the flow is blocked, the leakage of the leaked steam 32a can be reduced, and the thermal energy of the main flow 31 can be further effectively utilized.

  In the present embodiment, the diaphragm outer ring free-cutting portion 36 as the moving blade tip upstream side steam leakage suppression portion 33 is provided with the radial groove 51 along the radial direction, but the present invention is not limited to this example. For example, as shown in FIG. 12 of the seventh embodiment, the radial groove 51 may be provided in a direction opposite to the rotational direction R of the turbine rotor 52 and inclined at an angle α with respect to the radial line RL. Good.

  If the radial groove 51 is provided in the direction opposite to the rotational direction R of the turbine rotor 52, the swirl speed component of the leaked steam 32a can be further reduced to increase the radial speed component. Therefore, in order to prevent the leaked steam 32a from leaking, Even more effective.

  Further, in the present embodiment, the diaphragm outer ring free-cutting portion 36 as the rotor blade upstream portion steam leakage suppression portion 33 is provided with the radial groove 51 along the radial direction, but the present invention is not limited to this example. For example, as shown in FIG. 13 of the eighth embodiment, the radial groove 51 shown in the sixth embodiment may be combined with the circumferential groove 47 shown in the fifth embodiment.

  Combining the circumferential groove 47 with the radial groove 51 is more effective for preventing leakage of the leaked steam 32a.

1 is a longitudinal sectional view showing a first embodiment of a shaft sealing device according to the present invention. The elements on larger scale of the X section shown in FIG. The elements on larger scale of the Y section shown in FIG. The longitudinal cross-sectional view which shows 2nd Embodiment of the shaft-seal apparatus which concerns on this invention. The longitudinal cross-sectional view which shows 3rd Embodiment of the shaft-seal apparatus which concerns on this invention. The longitudinal cross-sectional view which shows 4th Embodiment of the shaft-seal apparatus which concerns on this invention. The longitudinal cross-sectional view which shows 5th Embodiment of the shaft-seal apparatus which concerns on this invention. Sectional drawing cut | disconnected from the AA arrow direction shown in FIG. The longitudinal cross-sectional view which shows 6th Embodiment of the shaft-seal apparatus which concerns on this invention. Sectional drawing cut | disconnected from the BB arrow direction shown in FIG. The front view seen from the CC arrow direction shown in FIG. The conceptual diagram which shows 7th Embodiment of the shaft-seal apparatus which concerns on this invention. The longitudinal cross-sectional view which shows 8th Embodiment of the shaft-seal apparatus which concerns on this invention. The longitudinal cross-sectional view which shows the conventional shaft seal apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Diaphragm outer ring 2 Diaphragm inner ring 3 Turbine nozzle 4 Main flow 5 Turbine rotor blade 6 Shroud 7, 8 Leakage steam 9 Labyrinth fin 10 Turbine disk 11 Turbine stage 12 Stationary part 13 Rotating part 21 Stationary part 22 Rotating part 23 Turbine nozzle 24 Diaphragm outer ring 25 Diaphragm inner ring 26 Turbine disk 27 Turbine rotor blade 28 Labyrinth fin 29 Shroud 30 Turbine stage 31 Main flow 32a, 32b Leakage steam 33 Rotor blade tip upstream steam leak suppression part 34 Rotor blade tip downstream steam leak suppression part 35 Shroud piece 36 Diaphragm outer ring free-cutting portion 37 Seal fin 38 Diaphragm inner ring free-cutting portion 39a, 39b Recess 40 Storage container 41 Connector 42 Projecting portion 43 Piston 44 Space chamber 45 Spring 46 Recess 47 Circumferential groove 48 Edge 4 9 Side 50 Inclined side 51 Radial groove 52 Turbine rotor

Claims (17)

A stationary part that sandwiches the outer peripheral side and inner peripheral side of the turbine nozzle between the diaphragm outer ring and the diaphragm inner ring, and a rotating part that implants the turbine rotor blade located downstream of the turbine nozzle in the turbine disk, In a shaft seal device provided with a labyrinth fin provided on the outer ring of the diaphragm, facing a shroud provided on the tip side of the turbine rotor blade, working steam is introduced into a gap between the upstream end of the shroud and the outer ring of the diaphragm. Leakage of working steam is caused in a gap between the upstream-side steam leakage suppression part for preventing the leakage and the downstream side of the turbine disk for planting the turbine blade and the inner ring of the diaphragm for supporting the adjacent turbine nozzle. A shaft seal device, comprising: a rotor blade root portion downstream side steam leakage suppression portion to prevent. 2. The moving blade tip upstream steam leakage suppression portion is configured by a shroud piece that protrudes from an upstream tip of a shroud, and a diaphragm outer ring free cut portion provided in a diaphragm outer ring. The shaft seal device according to 1. 2. The moving blade root downstream side steam leakage suppression portion is configured by a seal fin provided on the downstream side of the turbine disk and a diaphragm inner ring free cutting portion provided on an adjacent diaphragm inner ring. The shaft seal device according to 1. 3. The structure according to claim 1, wherein the moving blade tip upstream side steam leakage suppression portion is configured such that a housing container that houses the free-cutting portion for the diaphragm outer ring can be attached to and detached from the diaphragm outer ring. Shaft seal device. The upstream end of the moving blade tip steam leakage suppression portion is provided in a container that houses the free-cutting portion for the diaphragm outer ring, and a piston that slides in a space chamber formed in the diaphragm outer ring and a pressing force applied to the piston. 2. The shaft seal device according to claim 1, wherein the shaft seal device comprises a spring to be applied. The shaft sealing device according to claim 5, wherein the piston has a protruding portion at a tip. 2. The upstream end of the moving blade tip steam leakage suppression portion is provided with recesses arranged discretely along a circumferential direction in a free-cutting portion for a diaphragm outer ring housed in a housing container. The shaft seal device according to 4, or 5. The said moving blade front-end | tip part upstream steam leak suppression part provided the circumferential groove | channel along the circumferential direction in the free-cutting part for diaphragm outer rings accommodated in a storage container, Or the shaft seal device of 5. The circumferential groove has a flat side extending inward from the surface of the diaphragm outer ring free-cutting portion, and an inclination formed from an end portion of the side toward the surface of the diaphragm outer ring free-cutting portion. The shaft seal device according to claim 8, wherein the shaft seal device is formed by a side. The shaft seal according to claim 1, 4, or 5, wherein the upstream end of the moving blade tip steam leakage suppressing portion is provided with a radial groove along a radial direction in a free cutting portion for a diaphragm outer ring. apparatus. The radial groove is formed in a flat side extending perpendicularly from the surface of the free-cutting portion for the diaphragm outer ring toward the inside, and in an inclined shape from the end of this side toward the surface of the free-cutting portion for the diaphragm outer ring. The shaft sealing device according to claim 10, wherein the shaft sealing device is formed with an inclined side. The shaft sealing device according to claim 10, wherein the radial groove is provided along a radial line passing through a center of the turbine rotor. The shaft seal device according to claim 10, wherein the radial groove is configured to be inclined in a direction opposite to a rotation direction of the turbine rotor and with respect to a radial line. The shaft seal device according to claim 1, wherein the upstream end of the moving blade tip steam leakage suppressing portion is provided by combining a circumferential groove and a radial groove on the diaphragm outer ring free cut portion. The free-cutting portion for the outer ring ring is selected from Ni, Cr, Al, bentonite, Ni, Cr, Fe, Al, and boron nitride. The shaft seal device according to any one of? 8. The free-cutting portion for the inner ring of the diaphragm is selected from any of Ni, Cr, Al, bentonite, Ni, Cr, Fe, Al, and boron nitride. The shaft seal device according to any one of? A shaft seal device in which any one of claims 1 to 16 is applied to a steam turbine.

Images