JP4131739B2 - Steam turbine divider - Google Patents

Description

  The present invention relates to a steam turbine partition plate, and more particularly, to a steam turbine partition plate having excellent assembly efficiency without degrading turbine efficiency by devising a coupling means between a stationary blade and inner and outer rings.

  FIG. 6 is a turbine cross-sectional view showing a conventional steam turbine partition plate. In general, the internal structure of a turbine is configured by alternately providing a plurality of stages of stationary blades 71 and 72 and moving blades 73, 74, and 75 in a steam passage. The rotor blades 73, 74, and 75 are integrated with the rotor shaft 76, and rotate the rotor shaft 76 in response to the steam pressure. A partition plate (disk) 77 is provided between the rotor blade 73 (or 74) and the rotor blade 74 (or 75) to rectify steam and to maintain confidentiality between the rotor blades 73, 74, and 75. Yes. In addition, as shown to the figure, the partition plate 77 may be provided by connecting in multiple steps.

  The partition plate 77 includes stationary blades 71 and 72 serving as nozzles, inner rings 80 and 81 provided with seals 78 and 79 for maintaining confidentiality between the moving blades 73, 74, and 75, and a compartment 82. On the other hand, it is comprised with the outer ring | wheel 83 which fixes a stationary blade. The inner rings 80 and 81 are provided in order to ensure the static rigidity and dynamic rigidity of the stationary blades 71 and 72, and to reduce the leak amount, but may not be provided depending on the type of turbine. The stationary blades 71 and 72 are formed by cutting and then subjected to a manual polishing process.

  The inner rings 80 and 81, the stationary blades 71 and 72, and the outer ring 83 are welded and joined at a welding symbol 84 in the drawing. Further, after welding, annealing is performed to remove distortion. The partition plate 77 is formed in a donut shape so as to surround the rotor shaft 76, and therefore is manufactured by being divided into two by 180 degrees in consideration of assembly (for example, Patent Document 1).

JP 11-343807 A

  However, in the conventional steam turbine partition plate 77, dozens of the stationary blades 71 and 72 must be welded and assembled, or the partition plate 77 must be handled as an integral part during maintenance, so that production efficiency and repair work efficiency are poor. . Further, after welding, an annealing process for removing strain is indispensable, and this annealing process has a problem that the surface roughness of the polished stationary blades 71 and 72 is deteriorated.

  The surface roughness of the stationary blades 71 and 72 is one of the factors affecting the turbine efficiency for the steam turbine, and it is difficult to further polish after annealing. According to the latest pressure distribution analysis, it has been found that the stationary blades 71 and 72 do not necessarily have to be consolidated with the outer ring 83 and the inner rings 80 and 81 by welding.

  Accordingly, the present invention has been made in view of the above, and is a steam turbine that is excellent in assembly efficiency without deteriorating turbine efficiency by devising a coupling means between the stationary blades 71 and 72 and the inner and outer rings 80, 81, and 83. It aims at at least one of providing a partition plate and achieving cost reduction by drastically shortening the production period.

In order to achieve the above-described object, the steam turbine partition plate according to claim 1 is not required to be fixed to the generally donut-shaped inner ring having the fitting portion A on the outer peripheral side and the fitting portion A of the inner ring by welding. A stationary blade row including a plurality of stationary blades arranged in the radial direction in a state attached to the turbine. constrained to the turbine axial direction by fitting between the the a fitting portion B, and while being constrained locked circumferential direction by a key which is attached so as to protrude radially in the turbine axial direction side of the inner ring , And is not restricted in the radial direction .

In this invention, the inner ring has a fitting portion A such as a concave shape, a convex shape, or a T-shaped groove shape on the outer peripheral side, while the stationary blade has a convex shape, a concave shape, a T-shape on the radially inner side. It has a fitting part B such as a protruding shape. The steam turbine partition plate is configured by fitting these stationary blades and inner rings. Thereby, the steam turbine partition plate sufficiently secures its rigidity and significantly improves the efficiency of assembly and disassembly. In addition, assembling and disassembling efficiency is remarkably improved, so that the cost can be reduced by drastically shortening the production period. Here, the term “fitting” is a concept including, for example, engagement between a T-shaped groove shape and a T-shaped protrusion shape. In addition, the steam turbine partition plate configured by fitting the outer ring, the stationary blade, and the inner ring has sufficient rigidity, and remarkably improves the efficiency of assembly and disassembly. Here, the term “fitting” is a concept similar to the above-described invention. Further, when the stationary blade row is locked by the key protruding in the radial direction from the inner ring, the stator blade row is restrained in the circumferential direction. This eliminates the relative displacement between the stationary blade row and the inner ring. Further, since the stationary blade and the inner ring are coupled by fitting between the fitting portions, the stator blade is also restrained in the turbine axial direction in relation to the fitting portions, and the stationary blade row and the inner ring are not collapsed. On the other hand, the stator blade inner ring is not restrained in the radial direction. It is not necessary to lock all the stationary blades from the inner ring side with a key.

Further, the steam turbine partition plate according to claim 2 has a substantially donut-shaped outer ring having an outer peripheral side assembled to the vehicle interior wall and having a fitting portion E on the inner peripheral side, and an approximate donut having a fitting portion F on the outer peripheral side. When the turbine is provided with a fitting portion G that is fitted to the fitting portion E of the inner ring, the fitting portion E of the outer ring, and the fitting portion F of the inner ring without being fixed by welding. A stationary blade row having a plurality of stationary blades arranged at both ends, and is constrained in the turbine axial direction by the fitting of the fitting portion F and the fitting portion G, The inner ring is locked by a key attached so as to protrude in the radial direction on the side surface in the turbine axial direction of the inner ring and is restricted in the circumferential direction, but is not restricted in the radial direction .

In the present invention, the outer ring and the inner ring have fitting portions E and F having a concave shape, a convex shape, a T-shaped groove shape, etc. on the inner peripheral side and the outer peripheral side, respectively, while the stationary blade is on the radially outer side. Have fitting portions G and H such as a convex shape, a concave shape, and a T-shaped projection shape. By respectively fitting these, the steam turbine partition plate can be configured without going through a welding process. Therefore, the annealing process after welding can be omitted. In addition, the steam turbine partition plate configured by fitting the outer ring, the stationary blade, and the inner ring has sufficient rigidity, and remarkably improves the efficiency of assembly and disassembly. Here, the term “fitting” is a concept similar to the above-described invention. Further, when the stationary blade row is locked by the key protruding in the radial direction from the inner ring, the stator blade row is restrained in the circumferential direction. This eliminates the relative displacement between the stationary blade row and the inner ring. Further, since the stationary blade and the inner ring are coupled by fitting between the fitting portions, the stator blade is also restrained in the turbine axial direction by the relationship with the fitting portions, and the stationary blade row and the inner ring do not fall down. On the other hand, the stator blade inner ring is not restrained in the radial direction. It is not necessary to lock all the stationary blades from the inner ring side with a key.

Further, in the steam turbine partition plate according to claim 3, in the steam turbine partition plate, the fitting portion between the stationary blade and the inner ring has a shape that can be fitted at a central thickness portion of the inner ring. It is.

In this invention, the said fitting part is provided in the thickness center part of an inner ring | wheel. Here, the central portion of the inner ring thickness refers to a certain portion that crosses an imaginary line that bisects the thickness of the inner ring. By providing the fitting portion at the center of the thickness, the force on the inner ring due to the pressure change in the steam passage is less likely to affect the stationary blade.

  As described above, according to the steam turbine partition plate according to the present invention, since the steam turbine partition plate can be configured by fitting the stationary blade and the inner ring, the assembly efficiency is remarkably improved. Efficiency is also significantly improved. In particular, when maintaining a seal inside the inner ring, which is naturally expected to wear, only the inner ring can be easily removed, which is extremely convenient.

  Further, according to the steam turbine partition plate according to the present invention, the steam turbine partition plate can be configured by fitting the stationary blade and the outer ring, so that the assembly efficiency is remarkably improved and the maintenance efficiency is also remarkably improved. To do. Particularly during maintenance, it is possible to work on the adjacent moving blade and the moving blade seal attached to the tip of the moving blade without removing the outer ring, which is extremely convenient.

  In addition, according to the steam turbine partition plate according to the present invention, the steam turbine partition plate can be configured by mutual fitting with the inner ring, the stationary blade, and the outer ring, so that the welding process can be omitted. Therefore, an annealing process for the purpose of removing strain or the like can be omitted, and deterioration of the surface roughness of the stationary blade, which has been hitherto closed, can be prevented. Further, according to the present invention, the assembly efficiency is remarkably improved, and the efficiency during maintenance is remarkably improved. Particularly during maintenance, it is possible to work partially, which is extremely convenient.

  Further, according to the steam turbine partition plate according to the present invention, since the fitting portion between the stationary blade and the inner ring can be fitted at the central thickness portion of the inner ring, even if force is applied to the inner ring by the steam pressure. It is difficult to transmit to the stationary blade, and sufficient rigidity of the steam turbine partition plate can be secured.

  Further, according to the steam turbine partition plate according to the present invention, since the fitting portion between the stationary blade and the inner ring is joined through the pin through the overlapping portion, it is possible to prevent the stationary blade from being displaced and falling. Can do. As a result, the fitting between the stationary blade and the inner ring is ensured. On the other hand, in the steam turbine partition plate configured by fitting the stationary blade and the inner ring, the pins do not protrude in the turbine axial direction, and there is no need to consider pressure loss.

  Further, according to the steam turbine partition plate according to the present invention, the inner ring and the stationary blade are not restrained in the radial direction, so that a thermal expansion free structure is formed. That is, even when a temperature difference occurs in a transient state such as at the time of startup, the thermal stress can be made smaller than that of the conventional welded structure because they are not restrained from each other. Further, the inner ring is not displaced by the fitting portion between the stationary blade and the inner ring and the key attached to the side surface in the turbine axial direction, and the core can be held. Furthermore, since the inner ring is supported by the fitting portion and the key, the force applied to the inner ring is less likely to be transmitted as a moment to the stationary blade, and the burden on the nozzle is less than that of the conventional structure.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a cross-sectional view showing the internal structure of a steam turbine according to an embodiment of the present invention. Since the basic internal structure of the steam turbine is the same as that of the prior art, the description thereof will be omitted, and the description will focus on the steam turbine partition plate. The partition plates 4 and 5 provided between the rotor blades 1, 2, and 3 are constituted by an outer ring 6, stationary blades 7 and 8, and inner rings 9 and 10, respectively. The outer ring 6 has a generally donut-like shape with the outer peripheral side assembled to the inner wall of the passenger compartment 11 and the fitting part C (E) on the inner peripheral side. The outer ring 6 shown here is of a type that connects two partition plates, but is not limited to this and is often provided on each partition plate.

  The inner rings 9, 10 have a generally donut-like shape with carbon packing and labyrinth seals 15, 16 that close the gap with the rotor shaft 14 on the inner peripheral side, and a fitting portion A (F) on the outer peripheral side. Yes. The stationary blades 7 and 8 are composed of blades and members that support the blades, and are fitted into the fitting portion C (E) of the outer ring 6 and the fitting portion A (F) of the inner ring. Part D (G) and fitting part B (G) are provided at both ends in the radial direction when attached to the turbine.

  The outer ring 6, the stationary blade 7, and the inner ring 9 are fitted with respective fitting portions C (E), fitting portions D (G), fitting portions A (F), and fitting portions B (G). . Further, the outer ring 6, the stationary blade 8, and the inner ring 10 are fitted with respective fitting portions C (E), D (G), fitting portions A (F), and fitting portions B (G). Since the stator blades 7 and 8 are formed in a single block or a plurality of blocks, when the partition plates 4 and 5 are assembled, side entry is performed from the circumferential direction of the outer ring 6 and the inner rings 9 and 10 by 180 degrees. Moreover, if it is the shape of fitting part A (F) and fitting part B (G) as shown to the same figure, it can also be fitted to radial direction.

  In addition, the fitting portion A (F) between the stationary blades 7 and 8 and the inner rings 9 and 10 shown in FIG. . That is, when the fitting portion is formed as shown in the figure, even when the inner rings 9 and 10 are subjected to steam pressure and receive a force in the turbine axial direction, the force is not easily transmitted to the stationary blades 7 and 8 as a moment. . Therefore, only the thrust force acts on the stationary blades 7 and 8, the strength design of the stationary blades becomes easy, and sufficient rigidity can be secured. In addition, the thickness center part of the inner ring refers to a certain part straddling an imaginary line that bisects the thickness of the inner ring.

  The partition plates 4 and 5 are configured by fitting the outer ring 6, the stationary blades 7 and 8, and the inner rings 9 and 10 as described above, and the outer ring 6 and the stationary blades 7 and 8 are fixed in the circumferential direction by the caulks 23 and 24. The On the other hand, the stationary blades 7 and 8 and the inner rings 9 and 10 exist as many as the number of the stationary blades 7 and 8, but at least one of the fitting portions B (G) and A (F) is fitted by fitting. The overlapping portions are penetrated by pins 25 and 26 and joined. As a result, it is possible to prevent the displacement and fall of the stationary blade, and the fitting between the stationary blade and the inner ring can be ensured. Further, in the partition plates 4 and 5 thus configured, the pins 25 and 26 do not protrude in the turbine shaft direction, and it is not necessary to consider pressure loss.

  Thus, there are two significant meanings in configuring the partition plates 4 and 5 by fitting the fitting portions. One of them is that the assembly efficiency of the partition plates 4 and 5 and the work efficiency during maintenance can be remarkably improved. Conventionally, it has been considered that the stationary blades 7 and 8, which have a high pressure at a temperature of 500 ° C. or higher, must be firmly bonded to the outer ring 6 by welding. However, it has been found that the latest simulation technology advances that the stationary blades 7 and 8 do not necessarily have to be joined by welding in terms of strength.

  The other is that if it is not necessary to fix the stationary blades 7 and 8 to the outer ring 6 and the inner rings 9 and 10 by welding, annealing work after welding can be omitted. The annealing work has been performed for the purpose of removing distortion after welding and the like, but this work deteriorates the surface roughness of the stationary blades 7 and 8 that are manually polished after being cut out. The surface roughness of the stationary blades 7 and 8 is one factor that affects the turbine efficiency. It is known that if the surface roughness is deteriorated, the turbine efficiency is also deteriorated. Therefore, the present invention in which the steps of welding and annealing are omitted can improve the turbine efficiency as compared with the prior art.

  The above describes the case where the outer ring 6, the stationary blades 7 and 8, and the inner rings 9 and 10 are fitted to each other with the fitting portions to form the partition plate. , 8 may be fitted to form the partition plate. Even in this case, due to the fitting, the steam turbine partition plate can sufficiently secure its rigidity and can significantly improve the efficiency of assembly and disassembly. Further, assembling and disassembling efficiency is remarkably improved, so that the cost can be reduced by drastically shortening the production period.

  Contrary to the above, even if only the stationary blade and the inner ring are fitted to form the partition plate, the assembly efficiency is remarkably improved as described above, and the maintenance efficiency is remarkably improved. In particular, when maintaining a seal inside the inner ring that is naturally expected to be worn, only the inner ring can be easily removed, which is extremely convenient.

  2A to 2D are cross-sectional views illustrating the shape of the fitting portion between the outer ring and the stationary blade. In the type shown in FIG. 2A, the stationary blade side fitting portion D (G) is convex and the outer ring side fitting portion C (E) is concave, so that the stationary blade side can be prevented from falling in the turbine axis direction. The fitting portion D (G) is a type having small protrusions on the left and right. The type shown in FIG. 2-2 is a tree type and can be said to be a modification of the type shown in FIG. In the type shown in FIG. 2-3, the stationary blade side fitting portion D (G) is concave and the outer ring side fitting portion C (E) is convex, contrary to the types shown in FIGS. 2-1 and 2-2. It is a type. The point which has a small protrusion in the outer ring | wheel side for the fall prevention is the same as that of the type of FIGS. 2-1 and 2-2. The type shown in FIG. 2-4 is a type having a small protrusion on the stationary blade side in a modification of the type shown in FIG. 2-3. In addition, various shapes can be considered for the shape of the fitting portion between the outer ring and the stationary blade.

  3-1 to 3-4 are cross-sectional views illustrating the shape of the fitting portion between the stationary blade and the inner ring. The type shown in FIG. 3A is a type in which the inner ring side fitting portion A (F) is convex and the stationary blade side fitting portion B (G) is concave. The type shown in FIG. 3-2 is a modification of the type shown in FIG. 3A. The inner ring side fitting portion A (F) has a T-shaped projection, and the stationary blade side fitting portion B (G) has a T-shaped groove shape. It has become. The type shown in FIG. 3-3 is the opposite of the type shown in FIG. 3-2. The inner ring side fitting portion A (F) has a T-shaped groove shape, and the stationary blade side fitting portion B (G) has a T-shaped projection shape. It has become. The type shown in FIG. 3-4 is a so-called straddle tree type, in which the protrusion shape of the stationary blade side fitting portion B (G) has two stages, and has a straddle for stabilizing the fitting. Thus, the shape of the fitting portion between the stationary blade and the inner ring is not limited to the above, and various shapes are conceivable.

  FIGS. 4A and 4B are an external view and a cross-sectional view showing a structure for preventing the deviation between the stationary blade and the inner ring, and FIG. 4A is a front view and a cross-sectional view when a key is used. 4-2 is an external view when the stationary blades are arranged in a donut shape. As shown in these drawings, a row of stationary blades 41 configured by arranging a plurality of stationary blades 41 is locked by a key 43 attached so as to protrude radially on the side surface in the turbine axial direction of the inner ring 42. The

  When the row of the stationary blades 41 is locked by the key 43, it is restrained in the circumferential direction. As a result, the relative displacement between the row of the stationary blades 41 and the inner ring 42 is eliminated. Further, since the stationary blade 41 and the inner ring 42 are coupled by fitting the fitting portions of the thickness center portion, the stator blade 41 and the inner ring 42 are also constrained in the turbine axial direction in relation to the fitting portions. And the inner ring 42 will not fall over. On the other hand, the row of the stationary blades 41 and the inner ring 42 are not restrained in the radial direction. Note that it is not necessary to lock all the stationary blades with the key from the inner ring side, and the position of the key may be a boundary between the stationary blades.

  As described above, if the stationary blade 41 is restrained with respect to the inner ring 42, a structure free from thermal expansion caused by thermal expansion is obtained. That is, even when a temperature difference occurs in a transient state such as at the time of startup, the stationary blade 41 and the inner ring 42 do not restrain each other, so that the thermal stress can be made smaller than that of the conventional welded structure. Further, the inner ring 42 is not displaced by the fitting portion between the stationary blade 41 and the inner ring 42 and the key 43 attached to the side surface in the turbine axial direction, and the core can be held. Therefore, the seal 44 can also maintain an appropriate clearance with respect to the rotor shaft.

  Furthermore, since the inner ring 42 is supported by the fitting portion and the key 43, the force applied to the inner ring 42 is less likely to be transmitted as a moment to the stationary blade 41, and the burden on the nozzle is less than in the conventional structure. Since the inner ring 42 is only fitted, processing and assembly are facilitated, and the material yield is improved. Further, as in the prior art, the torsional rigidity of the inner ring 42 itself maintains sufficient rigidity against the pressure applied to the inner ring 42 and the stationary blade 41.

  FIG. 5 is a sectional view of a partition plate showing an application example of the partition plate. The partition plate 50 fits the fitting part C (E), the fitting part D (G), the fitting part B (G), and the fitting part A (F) of the outer ring 51, the stationary blade 52, and the inner ring 53. It is the same as the above that it is comprised by. This application example is characterized in that the piezoelectric element 58 is attached to the fitting portions D (G) and A (F) of the stationary blade. The wiring 59 to the piezoelectric element 58 is passed through holes formed in the stationary blade 52 and the outer ring 51.

  The thickness of the piezoelectric element 58 is changed by applying a voltage. By utilizing this, when the partition plate 50 is thermally stretched during a transition of the steam turbine or the like, it is possible to reduce the energized voltage and cancel the stretch. Therefore, the seal 60 attached to the inner peripheral portion of the inner ring 53 can always maintain an appropriate clearance with the rotor shaft 61 of the turbine, and thermal stress on the partition plate 50 can be suppressed. The attachment position of the piezoelectric element 58 is not limited to the illustrated position, and may be a fitting portion between the outer ring 51 and the stationary blade 52 or a fitting portion between the stationary blade 52 and the inner ring 53.

  In addition, since the piezoelectric element 58 can be used as a device that detects the force applied to the piezoelectric element 58 as a voltage, it is possible to detect which part of the partition plate 50 is applied with force and what deformation state it is caused by. it can. As described above, even when the piezoelectric element 58 is used, it can be used to maintain the appropriate clearance between the seal 60 and the rotor shaft 61. Note that the posture of the partition plate 50 may be maintained with a shape memory alloy that has been set to an appropriate temperature instead of the piezoelectric element.

  As described above, the steam turbine partition plate according to the present invention is useful for production and use of a steam turbine capable of improving assembly efficiency and improving maintainability.

It is sectional drawing which shows the internal structure of the steam turbine concerning embodiment of this invention. It is sectional drawing which shows the fitting part shape of an outer ring | wheel and a stationary blade. It is sectional drawing which shows the fitting part shape of an outer ring | wheel and a stationary blade. It is sectional drawing which shows the fitting part shape of an outer ring | wheel and a stationary blade. It is sectional drawing which shows the fitting part shape of an outer ring | wheel and a stationary blade. It is sectional drawing which shows the fitting part shape of a stationary blade and an inner ring | wheel. It is sectional drawing which shows the fitting part shape of a stationary blade and an inner ring | wheel. It is sectional drawing which shows the fitting part shape of a stationary blade and an inner ring | wheel. It is sectional drawing which shows the fitting part shape of a stationary blade and an inner ring | wheel. It is the front view and cross section which show the shift | offset | difference prevention structure of a stationary blade and an inner ring | wheel. It is an external view which shows the shift | offset | difference prevention structure of a stationary blade and an inner ring | wheel. It is sectional drawing of the partition plate which shows the application example of a partition plate. It is turbine sectional drawing which shows the conventional steam turbine partition plate.

Explanation of symbols

1, 2, 3, 73, 74, 75 Rotor blade 4, 5, 50, 77 Partition plate 6, 51, 83 Outer ring 7, 8, 41, 52, 71, 72 Stator blade 9, 10, 42, 53, 80 , 81 Inner ring 11, 82 Car compartment 15, 16, 60, 78, 79 Seal 23, 24 Caulking 25, 26 Pin 43 Key 58 Piezoelectric element 61, 76 Rotor shaft A (F), B (G), C (E) , D (G) Fitting part

Claims (3)

A generally donut-shaped inner ring having a fitting portion A on the outer peripheral side;
A stationary blade having a fitting portion B that is fitted to the fitting portion A of the inner ring without being fixed by welding on the radially inner side in a state attached to the turbine;
Have
A stationary blade row configured by arranging a plurality of the stationary blades is constrained in the turbine axial direction by the fitting of the fitting portion A and the fitting portion B, and is radial in the turbine axial direction side surface of the inner ring. A steam turbine partition plate characterized in that it is locked by a key attached so as to protrude in the circumferential direction and is restrained in the circumferential direction, but is not restricted in the radial direction . A substantially donut-shaped outer ring having an outer peripheral side assembled to the vehicle interior wall and having a fitting portion E on the inner peripheral side;
A generally donut-shaped inner ring having a fitting portion F on the outer peripheral side;
Stator blades having fitting portions G that are fitted to each of the fitting portion E of the outer ring and the fitting portion F of the inner ring without being fixed by welding at both ends in the radial direction when attached to the turbine. When,
Have
A stationary blade row configured by arranging a plurality of the stationary blades is constrained in the turbine axial direction by the fitting of the fitting portion F and the fitting portion G, and is radially in the turbine axial direction side surface of the inner ring. A steam turbine partition plate characterized in that it is locked by a key attached so as to protrude in the circumferential direction and is restrained in the circumferential direction, but is not restricted in the radial direction .   3. The steam turbine partition plate according to claim 1, wherein a fitting portion between the stationary blade and the inner ring has a shape that can be fitted at a thickness center portion of the inner ring.

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