JP4436273B2 - Turbine partition plate and turbine provided with the same - Google Patents

Description

  The present invention relates to a turbine such as a steam turbine or a gas turbine, and more particularly to the turbine partition plate.

  Conventionally, for example, a steam turbine is configured by alternately providing a plurality of stages of stationary blades and moving blades in a steam passage. The rotor blade is integrated with the rotor shaft, and the rotor blade receives the steam pressure and rotates the rotor shaft. An outer ring for fixing the stationary blade to the passenger compartment is provided on the turbine outer peripheral side of the stationary blade, and on the turbine inner peripheral side of the stationary blade, the airtightness between the stationary blade and the moving blade is maintained. An inner ring to which a seal is attached is provided. These inner ring, stationary blade, and outer ring are joined by welding to form a partition plate. Further, after welding, annealing is performed to remove distortion. In addition, since the partition plate is formed in a substantially donut shape so as to surround the rotor shaft, it is manufactured by being divided into two parts by 180 degrees in consideration of assembly.

  However, in such a partition plate, it is necessary to weld and assemble dozens of stationary blades, and since the partition plate must be handled as a unit during maintenance, production efficiency and repair work efficiency are poor, and cost is low. Become high. In addition, after welding, an annealing process for strain removal is indispensable, and this annealing process deteriorates the surface roughness of the polished stationary blade surface, disturbs the steam flow near the blade, and thus deteriorates the performance of the turbine. There was a problem.

  In view of this, Patent Document 1 discloses a steam turbine partition plate that has a structure excellent in assembly efficiency without degrading turbine efficiency by devising a coupling means between a stationary blade and inner and outer rings. This is provided with a seal that closes the gap with the rotor shaft on the inner peripheral side, a substantially donut-shaped inner ring having a fitting part A on the outer peripheral side, and a fitting part that fits into the fitting part A of the inner ring And a stationary blade having B on the radially inner side attached to the turbine.

  Here, the inner ring has a fitting portion A having a concave shape, a convex shape, a T-shaped groove shape or the like on its outer peripheral side, while the stationary blade has a convex shape, a concave shape, a T-shaped projection shape, or the like on its radial inner side. It has a fitting part B. The steam turbine partition plate is configured by fitting these stationary blades and inner rings. As a result, the steam turbine partition plate sufficiently secures its rigidity and remarkably improves the efficiency of assembly and disassembly.

In addition, Patent Document 2 discloses a configuration in which a stationary blade and an inner ring are fixed by a dovetail structure.
JP 2004-36546 A JP 2002-180802 A

  However, in the configuration described in Patent Document 1 or Patent Document 2 described above, when the rigidity of the stationary blade is low, that is, in the case of a relatively elongated shape, the amount of collapse due to the gap between the fitting portions of the stationary blade and the inner ring is small. In addition, the stress generated due to steam pressure increases.

  In view of such problems, an object of the present invention is to provide a turbine partition plate that can reliably fix a stationary blade and an inner ring with a simple configuration.

In order to achieve the above object, a turbine partition plate according to a first aspect of the present invention includes a stationary blade having a first fitting portion of a dovetail groove at a tip toward an inner diameter, and a second fitting fitted into the dovetail groove. In the turbine partition plate including an inner ring having a joint portion, at least a surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape, and the second fitting is performed on the surface of the first fitting portion. A pressure supply that abuts the surface of the joint portion, introduces the pressure of the driving gas between the first fitting portion and the second fitting portion, and presses the inner ring in the inner circumferential direction by the pressure. A groove is provided.

A turbine partition plate according to a second aspect of the present invention includes a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove. In the turbine partition plate, at least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape so that the surface of the second fitting portion abuts the surface of the first fitting portion. to, between said first fitting part and the second fitting portion, characterized in that a leaf spring for pressing said inner ring in the inner peripheral direction.

A turbine partition plate according to a third aspect of the present invention includes a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove. In the turbine partition plate, at least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape so that the surface of the second fitting portion is in contact with the surface of the first fitting portion. In addition, a spring seal is provided between the first fitting portion and the second fitting portion to press the inner ring in the inner circumferential direction.

A turbine partition plate according to a fourth aspect of the present invention includes a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove. In the turbine partition plate, at least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape so that the surface of the second fitting portion is in contact with the surface of the first fitting portion. In addition, an expansion material that presses the inner ring in its inner circumferential direction by thermal expansion is provided between the first fitting portion and the second fitting portion.

A turbine partition plate according to a fifth aspect of the present invention includes a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove. In the turbine partition plate, at least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape so that the surface of the second fitting portion is in contact with the surface of the first fitting portion. In addition, a curable filler is provided between the first fitting portion and the second fitting portion to press the inner ring in the inner circumferential direction.

A turbine partition plate according to a sixth aspect of the present invention includes a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove. In the turbine partition plate, at least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape so that the surface of the second fitting portion is in contact with the surface of the first fitting portion. Then, a bolt is screwed and inserted from the inner peripheral side of the inner ring to the first fitting part side, and the tip of the bolt is pressed against the first fitting part, so that the inner ring is moved in the inner peripheral direction. It is characterized by being pressed.

A turbine partition plate according to a seventh aspect of the present invention includes a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove. In the turbine partition plate, at least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape so that the surface of the second fitting portion is in contact with the surface of the first fitting portion. The caulking piece is inserted between the first fitting portion and the second fitting portion to press the inner ring in the inner circumferential direction.

A turbine partition plate according to an eighth aspect of the present invention includes a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove. In the turbine partition plate, at least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape so that the surface of the second fitting portion is in contact with the surface of the first fitting portion. The caulking piece is inserted between the outer peripheral surface of the inner ring and the turbine radial direction inner end surface of the stationary blade, thereby pressing the inner ring in the inner peripheral direction.

The turbine partition plate according to the invention described in claim 9 is characterized in that both the upstream and downstream surfaces of the dovetail groove in the driving gas flow direction have an undercut shape provided with a taper.

  According to the present invention, the downstream surface of the dovetail groove in the driving gas flow direction is undercut, and the surface of the second fitting portion that is in contact with the downstream surface is also undercut. With this configuration, it is possible to provide a turbine partition plate that can reliably fix the stationary blade and the inner ring.

  Further, by providing a pressure supply groove in the dovetail fitting part and pressing the inner ring in the inner circumferential direction by steam pressure, the gap of the fitting part is set to 0 during turbine operation without using a welding structure. be able to. Thereby, a stationary blade can be restrained with an inner ring, the reliability of a turbine partition plate and by extension, a turbine improves, and turbine efficiency improves.

  In addition, by using a spring, an expansion / filling material, a bolt, a caulking piece, or the like instead of the steam pressure, the gap of the fitting portion can be set to 0 as a configuration for pressing the inner ring in the inner circumferential direction. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the internal structure of a steam turbine to which the present invention is applied. As shown in the figure, the steam turbine is provided with a plurality of stages (here, 3 stages) by alternately providing stationary blades 1, 2, 3 and moving blades 4, 5, 6 in the steam passage supplied as shown by arrows. Stage). However, the number of blade stages is not limited to that shown in the figure, and other stages may be used. The rotor blades 4, 5, 6 are integrated with the rotor shaft 7 and rotate the rotor shaft 7 in response to the steam pressure.

  On the outer peripheral side of the stationary blades 1, 2, and 3 in the radial direction of the turbine, an outer ring 8 is provided for fixing the stationary blades to a vehicle compartment (not shown). Inner rings 12, 13, and 14 are provided on the inner peripheral side of the turbine blades 1, 2, and 3 in the radial direction of the turbine, respectively, and the airtightness between the stationary blades and the moving blades is maintained on the inner peripheral side thereof. Seals 9, 10, and 11 are provided for the purpose. The outer ring 8, the stationary blades 1, 2, 3 and the inner rings 12, 13, 14 constitute a partition plate 15. The partition plate 15 functions to rectify the supplied steam and to maintain airtightness between the rotor blades 4, 5, and 6. In addition, seals 4a, 5a, and 6a for maintaining airtightness between the stationary blades and the moving blades are respectively attached to the outer peripheral sides of the moving blades 4, 5, and 6 in the turbine radial direction.

  The outer ring 8 has a substantially donut shape in which the outer peripheral side is assembled to a vehicle interior wall (not shown) and the inner peripheral side has fitting portions 8a, 8b, and 8c for fitting with the stationary blades. The outer ring 8 shown here is of a system that connects a plurality of stages of stationary blades, but is not limited to this, and may be a system in which separate outer rings are fitted to the stationary blades of each stage. The inner rings 12, 13, 14 are provided with the seals 9, 10, 11 that close the gap with the rotor shaft 7 on the inner peripheral side, and are fitted with fitting portions 12 a, 13 a, 14 a that fit the stationary blades on the outer peripheral side. Each has a substantially donut shape.

  The stationary blades 1, 2, and 3 have fitting portions 1 a, 2 a, and 3 a that fit into the fitting portions 8 a, 8 b, and 8 c of the outer ring 8, respectively, at the outer end in the turbine radial direction. , 13, and 14 have fitting portions 1b, 2b, and 3b that fit into the fitting portions 12a, 13a, and 14a, respectively, at the inner end in the turbine radial direction. When the partition plate 15 is assembled, the stationary vanes 1, 2, and 3 are respectively separated from the circumferential direction of the outer ring 8 that is divided into two parts by 180 degrees and the inner rings 12, 13, and 14 that are divided into four parts every 90 degrees. It is inserted while being fitted at the fitting portion.

  And the outer ring | wheel 8 and the stationary blades 1, 2, and 3 are fixed with respect to the circumferential direction by the caulks 16, 17, and 18. FIG. Further, the inner rings 12, 13, 14 and the stationary blades 1, 2, 3 are fixed in the circumferential direction by a set screw which will be described later. Moreover, 21 shown with the dashed-two dotted line is the volt | bolt which fastens the outer ring | wheel 8 divided | segmented up and down, and has shown the arrangement | positioning relationship seen from the circumferential direction here. Actually, it is provided on the turbine horizontal surface of the outer ring 8. Details will be described later.

  FIG. 2 is an enlarged cross-sectional view of the inner ring of the turbine partition plate and the vicinity thereof according to the first embodiment of the present invention. In this embodiment, as shown in the figure, a convex fitting portion 14a provided on the outer peripheral side of the inner ring 14 and a concave fitting portion 3b provided on the turbine radial direction inner end of the stationary blade 3 are fitted. is doing. And the fitting part 3b becomes what is called a dovetail whose width | variety of a bottom part is wider than an opening part, and is a structure which the fitting part 14a fits along this dovetail groove shape. In this embodiment, the stationary blade 3 and the inner ring 14 are representatively described, but the same applies to the relationship between the other stationary blades and the inner ring.

  Specifically, the rising surface downstream of the steam flow direction indicated by the arrow (the surface rising in the turbine radial direction), that is, the rising surface 3ba of the fitting portion 3b and the rising surface 14aa of the fitting portion 14a, respectively, are under. The structure is inclined (provided with a taper) in the direction of cutting. On the other hand, the rising surface on the upstream side in the steam flow direction, that is, the rising surface 3bb of the fitting portion 3b and the rising surface 14ab of the fitting portion 14a rise substantially vertically.

  In addition, a fitting convex portion 11 a provided on the outer peripheral side of the seal 11 is fitted in a fitting concave portion 14 b provided on the inner peripheral side of the inner ring 14, whereby the seal 11 is provided on the inner peripheral side of the inner ring 14. Has been. However, the inner ring and the seal may be integrated. Reference numeral 19 shown by a two-dot chain line is the set screw for fixing the inner ring 14 and the stationary blade 3, and here shows the positional relationship as seen from the circumferential direction. Actually, it is provided on the turbine horizontal surface of the inner ring 14. Details will be described later.

  As described above, by making the fitting part of the inner ring with respect to the stationary blade convex, the cross-sectional area of the inner ring can be increased, and the torsional rigidity of the inner ring can be kept high. Moreover, it becomes easy to ensure the space for attaching a seal | sticker. However, a configuration in which the fitting portion of the inner ring with respect to the stationary blade is concave is also possible. The inner ring shown in FIG. 2 and the structure in the vicinity thereof are similarly applied to the other inner rings in this embodiment.

  Further, as a method of bringing the convex fitting portion 14a provided on the outer peripheral side of the inner ring 14 into contact with the concave fitting portion 3b provided at the turbine radial direction inner end of the stationary blade 3, a convex fitting is employed. The portion 14a and the concave fitting portion 3b may be in contact with each other with almost no gap, or may be a close fit, and the member of the convex fitting portion 14a is more thermally expanded than the member of the concave fitting portion 3b. You may comprise as a thing with a big coefficient. In this case, the shape of the convex fitting part 14a and the concave fitting part 3b can be selected arbitrarily.

  Further, the rising surface (the surface rising in the substantially radial direction of the turbine) on the downstream side in the steam flow direction, that is, the rising surface 3ba of the fitting portion 3b and the rising surface 14aa of the fitting portion 14a are inclined in the direction of undercut. On the other hand, the rising surface on the upstream side in the steam flow direction, that is, the rising surface 3bb of the fitting portion 3b and the rising surface 14ab of the fitting portion 14a are configured to rise substantially vertically. However, the inner ring 14 and the stationary blade 3 can be securely fixed.

  FIG. 3 is a detailed cross-sectional view of the inner ring of the turbine partition plate according to the present embodiment and the vicinity thereof. As shown in the figure, a pressure supply groove a is provided from the outer peripheral surface of the inner ring 14 on the upstream side in the steam flow direction indicated by the arrow to the rising surface 14ab. This is provided corresponding to each stationary blade 3 arranged over the entire circumference of the turbine. Such a pressure supply groove may be provided on the opposite stationary blade 3 side. Or you may provide the pressure introduction hole which connects the fitting part 3b and the outer side of the stationary blade 3 instead of providing a pressure supply groove | channel. FIG. 4 is a view showing an example of the pressure supply groove as seen from the outer peripheral side of the inner ring. In this example, the outer peripheral surface of the inner ring 14 is started to be cut from the upstream side in the steam flow direction by an end mill or the like, and is cut to the rising surface 14ab to form a pressure supply groove a having an R surface. Of course, it is not limited to such a processing method.

  Thus, by providing the pressure supply groove, the upstream steam pressure is transmitted through the pressure supply groove a during turbine operation, and between the outer peripheral surface 14ac of the fitting portion 14a and the bottom surface 3bc of the fitting portion 3b. The inner ring 14 is pressed in the inner circumferential direction by this pressure. At this time, the rising surface 14aa of the fitting portion 14a contacts and slides on the rising surface 3ba of the fitting portion 3b, and the inner ring 14 moves upstream in the steam flow direction. As a result, the clearance between the rising surfaces 3ba and 14aa becomes 0, and the clearance between the rising surfaces 3bb and 14ab also becomes 0, so that the fitting portions 3b and 14a are securely fitted, and the inner ring 14 is against the stationary blade 3. Fixed. As described above, since the fitting portion comes into close contact with a simple configuration, the reliability of the turbine partition plate and thus the turbine is improved, and the turbine efficiency is improved.

  In addition, the leaf | plate spring 20 is provided between the outer peripheral surface 14ac of the fitting part 14a, and the bottom face 3bc of the fitting part 3b. This is to keep the inner ring lightly pressed and fixed to the inner peripheral side for the convenience of assembling the turbine partition plate. As shown in the perspective view of FIG. 5A, the shape of the leaf spring 20 is assumed to be provided with tongue-like cut-and-raised portions 20a at predetermined intervals on a belt-like plate. As the material of the leaf spring 20, for example, Inco718 (manufactured by Inconel), which is a heat-resistant alloy, is used.

  Further, as shown in FIG. 5B, a belt-shaped plate formed in a corrugated shape or other shapes, for example, a C-shaped spring seal having a C-shaped cross section may be used. As shown in FIG. 8, when the C-type spring seal 22 is used, the opening 22a is disposed so as to face the upstream side in the steam flow direction. In this case, the seal is expanded and deformed by the high-pressure vapor pressure entering from the nozzle dividing surface, so that the fitting portion 3b (precisely between the outer peripheral surface 14ac of the fitting portion 14a and the bottom surface 3bc of the fitting portion 3b). Will be spread. However, the nozzle dividing surface here is an adjacent surface between the turbine radial direction inner ends (so-called shrouds) of each stationary blade arranged in the turbine circumferential direction.

  In addition to the above-described belt-like plate springs, wave-like plate springs, and C-type spring seals, an expansion material, a curable filler, or the like may be used. As the expansion material, a material having a higher linear expansion coefficient than the material of the stationary blade shroud or the inner ring is selected. In the case of using an expansion material, the fitting portion 3b is pushed and expanded by thermal expansion during turbine operation. On the other hand, in the case of using a curable filler, the fitting portion 3b is pressurized by injecting into the fitting portion 3b. In either case, the gap between the rising surfaces 3ba and 14aa is zero, and the gap between the rising surfaces 3bb and 14ab is also zero, so that the fitting portions 3b and 14a are securely fitted, and the inner ring 14 Is fixed to the stationary blade 3.

  Further, as shown in FIG. 9, a bolt hole 14c is provided to penetrate from the fitting recess 14b of the inner ring 14 to the outer peripheral surface 14ac of the fitting portion 14a, and the bolt 23 is tightened from the side of the fitting recess 14b, that is, screwed. And it is good also as a structure which presses the front-end | tip against the bottom face 3bc of the fitting part 3b of the stationary blade 3. FIG. The inner ring 14 is pressed in the inner circumferential direction by pressing the bolt 23 against the bottom surface 3bc. At this time, since the rising surface 14aa of the fitting portion 14a is in contact with the rising surface 3ba of the fitting portion 3b and slides, the clearance between the rising surfaces 3ba and 14aa becomes 0, and between the rising surfaces 3bb and 14ab. The clearance is also zero, and the inner ring 14 is fixed to the stationary blade 3. Such a pressing structure using bolts is provided corresponding to each stationary blade arranged over the entire circumference of the turbine. Thus, the rising surface can be easily brought into close contact by inserting and pressing the bolt.

  Further, as shown in FIG. 10, a piece hole 3 c that communicates between the fitting portion 3 b and the outside of the stationary blade 3 is provided, and the outer peripheral surface 14 ac of the fitting portion 14 a passes through the piece hole 3 c from the outside of the stationary blade 3. The caulking piece 24 may be driven between the bottom surface 3bc of the fitting portion 3b. Thus, by driving the caulking piece 24, the inner ring 14 is pressed in the inner circumferential direction. At this time, since the rising surface 14aa of the fitting portion 14a is in contact with the rising surface 3bb of the fitting portion 3b and slides, the gap between the rising surfaces 3ba and 14aa becomes 0, and between the rising surfaces 3bb and 14ab The clearance is also zero, and the inner ring 14 is fixed to the stationary blade 3.

  Such a pressing structure by the caulking piece is arranged over the entire circumference of the turbine. The structure for driving the caulking piece may be provided on either the turbine inlet side, that is, the upstream side in the steam flow direction, or the turbine outlet side, that is, the downstream side in the steam flow direction. The figure shows a state where it is provided on the turbine inlet side. Such a driving structure by the caulking piece is provided corresponding to each stationary blade disposed over the entire circumference of the turbine. In this way, the rising surface can be easily brought into close contact with the caulking piece.

  Further, as shown in FIG. 11, in the gap between the outer peripheral surface of the inner ring 14 and the turbine radial direction inner end surface of the stationary blade 3, from both the turbine inlet side and the outlet side to the rising surfaces 14ab and 14aa of the fitting portion 14a, The caulking piece 25 may be driven in. Thus, by driving the caulking piece 25, the gap between the inner ring 14 and the stationary blade 3 is pushed wide. At this time, since the rising surface 14aa of the fitting portion 14a is in contact with the rising surface 3bb of the fitting portion 3b and slides, the gap between the rising surfaces 3ba and 14aa becomes 0, and between the rising surfaces 3bb and 14ab The clearance is also zero, and the inner ring 14 is fixed to the stationary blade 3. Such a driving structure by the caulking piece is provided corresponding to each stationary blade disposed over the entire circumference of the turbine. In this way, the rising surface can be easily brought into close contact with the caulking piece.

  FIG. 6 is a diagram schematically showing a modification of the inner ring of the turbine partition plate according to the present embodiment and its vicinity. Here, the rising surface downstream of the steam flow direction indicated by the arrow (the surface rising in the substantially radial direction of the turbine), that is, the rising surface 3ba of the fitting portion 3b, the rising surface 14aa of the fitting portion 14a, and the upstream of the steam flow direction. The rising surface on the side, that is, the rising surface 3bb of the fitting portion 3b and the rising surface 14ab of the fitting portion 14a are each inclined in the direction of undercut (provided with a taper). As a result, the fitting portions 3b and 14a are more reliably fitted in a balanced manner on the inclined surfaces on both the upstream and downstream sides.

  FIG. 7 is a view of the turbine partition plate according to the present embodiment as viewed from the upstream side in the steam flow direction. As shown in the figure, the partition plate 15 includes a stationary blade 1 on each of the upper and lower sides between an outer ring 8 divided into two parts vertically by 180 degrees and an inner ring 12 divided into four parts vertically and horizontally by 90 degrees. It is inserted from the circumferential direction while being fitted by the fitting portions 1a and 1b. Similarly to this, the stator blades 2, 3 of each stage not shown are arranged on the back side of the stator blade 1, and the inner rings 13, not shown of FIG. 14 are arranged. In addition, illustration is abbreviate | omitted about the stationary blade 1 of the lower half in the figure.

  As described above, the inner ring can be absorbed not only in the upper and lower but also in the left and right, so that the thermal elongation of the inner ring can be absorbed. In this thermal elongation, heat generated by sliding between the seal provided on the inner peripheral side of the inner ring and the rotor shaft is transmitted to the inner ring, and the inner ring expands in the circumferential direction. When the inner ring expands in the circumferential direction, it has an adverse effect of spreading in the outer circumferential direction and pressing the stationary blades, and crushing the caulks 16, 17, and 18 that fix the stationary blades to the outer ring. Therefore, a configuration is adopted in which the thermal elongation of the inner ring 12 is absorbed by providing a gap between the vertical alignment surfaces v of the inner ring 12 divided into left and right. The same applies to the inner rings 13 and 14. Another advantage is that the assemblability during production is greatly improved.

  The inner ring 12 and the stationary blade 1 are screwed and fixed in the circumferential direction by a set screw 19 on the horizontal alignment surface h on the left and right sides and are prevented from rotating. The same applies to the inner rings 13 and 14 and the stationary blades 2 and 3. After the partition plate 15 is assembled in a state where it is divided into two vertically, the left and right horizontal alignment surfaces H of the upper and lower outer rings 8 are in contact with each other (gap 0), and the upper and lower outer rings 8 and the upper and lower The partition plate 15 is fastened and fixed by bolts 21. Thereby, the partition plate 15 is assembled.

  At this time, a gap of about 0.2 mm is generated between the horizontal alignment surfaces h of the upper and lower inner rings 12. Therefore, overlay welding is performed on the horizontal alignment surface h in advance, and when the upper and lower outer rings 8 are fastened by the bolts 21, the overlay welding is crushed between the horizontal alignment surfaces h of the upper and lower inner rings 12. It is good also as a structure. As a result, the gap is filled, the airtightness of the horizontal alignment surface can be maintained, and the amount of collapse can be reduced. In the drawing, the set screw 19 and the bolt 21 positioned inside the partition plate 15 are seen through.

  As described in the above embodiments, in the turbine partition plate of the present invention, a pressure supply groove is provided in the dovetail fitting portion, and the inner ring is pressed in the inner circumferential direction by the steam pressure, so that the welding structure is Without using, the gap of the fitting portion can be set to zero during turbine operation. Thereby, a stationary blade can be restrained with an inner ring.

  More specifically, particularly when the stationary blade has low rigidity, that is, in a relatively elongated shape, when the stationary blade is subjected to steam pressure, the turbine inner end of the stationary blade moves downstream in the steam flow direction. At the same time, it is displaced in the outer circumferential direction. Therefore, the inner ring exerts the band effect, and by providing the dovetail fitting portion and the pressure supply groove, the inner ring pulls each stationary blade toward the inside of the turbine and suppresses the displacement of the turbine inner end of the stationary blade, The amount of elastic collapse can be reduced.

  In addition, by adopting a structure that does not use welding, high strength materials that cannot be welded, such as nickel chrome steel and nickel chrome molybdenum steel, can be used for the most severe stator blades in terms of strength. The turbine performance can be improved and the size can be reduced.

  In addition, since the steam pressure received is different between the stationary blade arranged upstream of the steam flow direction and the stationary blade arranged downstream, the inclination angle of the undercut surface is changed accordingly to adjust the fitting force. It is also possible to configure such that.

  The driving gas referred to in the claims corresponds to the vapor in the embodiment. In the above embodiment, the steam turbine is described, and the configuration in which the pressure of the steam that is the driving gas is introduced into the fitting portion is shown. However, the present invention can also be applied to the gas turbine. It can be set as the structure which introduce | transduces into a fitting part.

Sectional drawing which shows an example of the internal structure of the steam turbine to which this invention is applied. 1 is an enlarged cross-sectional view of an inner ring of a turbine partition plate and its vicinity according to a first embodiment of the present invention. The detailed cross section of the inner ring | wheel of the turbine partition plate which concerns on a present Example, and its vicinity. The figure which shows an example which looked at the pressure supply groove from the inner ring outer peripheral side. The perspective view which shows the shape of a leaf | plate spring. The figure which shows the modification of the inner ring | wheel of the turbine partition plate which concerns on a present Example, and its vicinity. The figure which looked at the turbine partition plate which concerns on a present Example from the flow direction upstream. The detailed cross-sectional view of the inner ring | wheel of the turbine partition plate using a C-type spring seal, and its vicinity. The detailed cross section of the inner ring | wheel of the turbine partition plate using a volt | bolt, and its vicinity. The detailed cross section of the inner ring | wheel of a turbine partition plate and its vicinity which used the caulking piece for the fitting part. The detailed cross section of the inner ring | wheel of a turbine partition plate and its vicinity which used the caulking piece for the clearance gap between an inner ring | wheel and a stationary blade.

Explanation of symbols

1-3 Stator blade 4-6 Rotor blade 7 Rotor shaft 8 Outer ring 9-11 Seal 12-14 Inner ring 15 Partition plate 16-18 Caulking 19 Set screw 20 Leaf spring 21, 23 Bolt 22 C spring seal 24, 25 Caulking piece

Claims (10)

In a turbine partition plate comprising a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove,
At least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape, and the surface of the second fitting portion is in contact with the surface of the first fitting portion,
Introducing pressure of the drive gas between the said second fitting portion and the first fitting part, you characterized in that a pressure supply grooves pressed against the inner circumferential direction of the inner ring by pressure turbines partition plate. In a turbine partition plate comprising a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove,
At least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape, and the surface of the second fitting portion is in contact with the surface of the first fitting portion,
Wherein between the first fitting part and the second fitting part, wherein the to filter turbine partition plate in that a leaf spring for pressing said inner ring in the inner peripheral direction. In a turbine partition plate comprising a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove,
At least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape, and the surface of the second fitting portion is in contact with the surface of the first fitting portion,
Wherein between the first fitting part and the second fitting part, wherein the to filter turbine partition plate in that a spring seal pressing said inner ring in the inner peripheral direction. In a turbine partition plate comprising a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove,
At least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape, and the surface of the second fitting portion is in contact with the surface of the first fitting portion,
Wherein between the first fitting part and the second fitting portion, the thermal expansion by the inner ring and the inner periphery, characterized in that the expansion material is provided for pressing in a direction to filter turbine partition plate. In a turbine partition plate comprising a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove,
At least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape, and the surface of the second fitting portion is in contact with the surface of the first fitting portion,
Wherein between the first fitting part and the second fitting part, wherein the to filter turbine partition plate in that a curable filling material is pressed against the inner ring in the inner peripheral direction. In a turbine partition plate comprising a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove,
At least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape, and the surface of the second fitting portion is in contact with the surface of the first fitting portion,
A bolt is screwed and inserted from the inner peripheral side of the inner ring to the first fitting part side, and the tip of the bolt is pressed against the first fitting part so as to press the inner ring in the inner peripheral direction. features and to filter turbine partition plate that was. In a turbine partition plate comprising a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove,
At least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape, and the surface of the second fitting portion is in contact with the surface of the first fitting portion,
Wherein by inserting the caulking piece between the first fitting part and the second fitting part, wherein the to filter turbine partition plate that was pressed against the inner ring in the inner peripheral direction. In a turbine partition plate comprising a stationary blade having a first fitting portion of a dovetail groove at a tip toward the inner diameter, and an inner ring having a second fitting portion fitted into the dovetail groove,
At least the surface on the downstream side in the driving gas flow direction of the dovetail groove has a tapered undercut shape, and the surface of the second fitting portion is in contact with the surface of the first fitting portion,
By inserting the caulking piece between the outer peripheral surface and the turbine radially inner end surface of the vane of the inner ring, features and to filter turbine partition plate that was pressed against the inner ring in the inner peripheral direction thereof. The turbine partition plate according to any one of claims 1 to 8, wherein both the upstream and downstream surfaces of the dovetail groove in the driving gas flow direction have an undercut shape provided with a taper. Turbine with turbine partition plate according to any one of claims 1 to 9.

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