JP2008144687A - Turbine stationary blade structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbine stationary blade structure enabling effective cost reduction of a turbine. <P>SOLUTION: In the turbine stationary blade structure provided with an outer ring implant outer shroud 3 on one end of each nozzle blade 2 and an inner shroud 4 on which a labyrinth seal 5 installed in a gap with a turbine rotor can be installed on another end thereof, alternate steps 4a, 4b in opposing surfaces of the inner shroud of adjoining nozzle blades are provided and are made in contact on over-all surface as a self restraint means increasing rigidity in a circumference direction of the inner shroud of each nozzle blade. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a turbine vane structure suitable for use in a steam turbine or a gas turbine.

  In a steam turbine or a gas turbine, a combination of moving blades that protrude radially from a rotor and stationary blades that cause a working fluid to collide with the moving blades at a predetermined angle are arranged in series. The stationary blade is attached between the outer ring and the inner ring, and constitutes an annular turbine partition plate (also expressed as a nozzle diaphragm).

  Conventionally, a turbine partition plate has been manufactured by welding a large number of parts. However, manufacturing in this manner is inferior in workability and cost. In addition, since distortion occurs when welding is performed, it is necessary to remove the strain by annealing in a later process.However, the stationary blade that has undergone the annealing process has a rough surface that has been polished, and disturbs the flow of the working fluid. Therefore, there is a problem that the turbine performance deteriorates.

  Therefore, recently, assembling-type turbine partition plates that complete the final form without using welding are often used. Specifically, the outer ring and the inner ring are divided at a predetermined angle, and the stationary blade divided pieces are fitted between the outer ring and the inner ring. Finally, the outer ring divided pieces and the inner ring divided pieces are bolted together. By combining them, an annular turbine partition plate is completed. Examples of such an assembly type turbine partition plate can be seen in Patent Document 1 and Patent Document 2.

JP 2003-97218 A (page 8-13, FIG. 1-23) Japanese Patent Laying-Open No. 2005-146896 (page 6-9, FIG. 1-5)

  By the way, in the turbine stationary blade structure disclosed in Patent Literature 1 and Patent Literature 2, by adopting an assembly type without welding, cost reduction by man-hour reduction and avoidance of deterioration of blade surface roughness due to heat treatment are achieved. Although the performance improvement based on this can be achieved, in recent intense international competition, the demand for lower cost and higher performance of the turbine has become more intense, and further simplification of the turbine vane structure is desired.

  The present invention has been made in view of the above-described situation, and an object of the present invention is to provide a turbine vane structure capable of effectively reducing the cost of a turbine.

In order to achieve such an object, a turbine stationary blade structure according to the present invention includes an outer shroud for implanting an outer ring at one end of each nozzle blade, and a seal member interposed in a gap with the turbine rotor at the other end. In a turbine vane structure with an inner shroud that can be mounted,
Self-restraining means for improving the circumferential rigidity of the inner shroud in each nozzle blade is provided.

  Further, the self-restraining means is characterized in that staggered steps are provided on the opposing surfaces of the inner shrouds of adjacent nozzle blades so as to be brought into full contact with each other.

  Further, as the self-restraining means, an open groove that penetrates in the circumferential direction on the side surface of the inner shroud is formed so as to communicate with at least the plurality of nozzle blades, and at least the plurality of nozzle blades are inserted into these open grooves. It is characterized in that a linear piece having a length extending over is fitted.

  Further, as the self-restraining means, a caulking allowance capable of being tightened at the time of assembling the outer ring is provided on the end face of the inner shroud of the nozzle blade located on the mating surface of the outer ring divided in the circumferential direction. .

  Further, the self-restraining means is characterized in that recesses capable of being driven in the radial direction and / or the axial direction are formed opposite to each other between the opposing surfaces of the inner shrouds of adjacent nozzle blades.

  Further, as the self-restraining means, a shearing key is formed so as to straddle the adjacent inner shroud in the fitting hole formed so as to face each other on the opposing surfaces of the inner shrouds of the adjacent nozzle blades. It is characterized by inserting.

  Further, as the self-restraining means, a locking structure including a groove and a protrusion is provided between the opposing surfaces of the inner shrouds of adjacent nozzle blades.

  Further, as the self-restraining means, a plurality of nozzle blades are integrally formed to form a spelling blade.

  According to the turbine vane structure according to the present invention, the cost can be further reduced by simplification due to the elimination of the inner ring, while the circumferential rigidity of the inner shroud in each nozzle blade is improved by self-restraining means. Can be avoided, and damage to the nozzle blades can be avoided.

  Hereinafter, a turbine stationary blade structure according to the present invention will be described in detail with reference to the drawings by way of examples.

  FIG. 1 is a structural explanatory view of a turbine vane structure showing Embodiment 1 of the present invention, where FIG. 1 (a) is a front view of the main part, and FIG. is there.

  As shown in the figure, an outer shroud 3 formed integrally with one end of each nozzle blade 2 is implanted on the inner surfaces of the outer rings 1A and 1B divided in half, and the other end of each nozzle blade 2 is illustrated. An inner shroud 4 to which a labyrinth seal (seal material) 5 interposed in a gap with the turbine rotor not to be attached is integrally formed.

  The outer shroud 3 of each nozzle blade 2 is fitted in a fitting groove 6 formed on the inner surface side of the outer rings 1A, 1B by sequentially sliding from the circumferential direction. Further, the labyrinth seal 5 is fitted in a fitting groove 7 formed on the inner surface side of the inner shroud 4 of each nozzle blade 2 by sliding from the circumferential direction.

  In this embodiment, at least a plurality of nozzle blades 2 are provided with open grooves 8a and 8b penetrating in the circumferential direction on both side surfaces of the inner shroud 4 of each nozzle blade 2 in the turbine stage (rotor shaft) direction. The metal linear pieces 9a and 9b having a length straddling at least a plurality of the nozzle blades 2 are fitted into the open grooves 8a and 8b, respectively. Accordingly, the open grooves 8a and 8b and the linear pieces 9a and 9b fitted therein constitute self-restraining means for improving the circumferential rigidity of the inner shroud 4 in each nozzle blade 2.

  As described above, in this embodiment, the inner ring 102 in the conventional turbine stationary blade structure shown in FIG. 10 is eliminated, so that the cost can be further reduced by the simplification of the structure, while the rigidity of the linear pieces 9a and 9b described above is achieved. The rigidity in the circumferential direction of the inner shroud 4 in each nozzle blade 2 is improved, thereby reducing the collapse of the nozzle blade 2 and preventing the nozzle blade 2 from being damaged.

  Incidentally, since the stationary blade of the steam turbine receives a load in the rotor axial direction due to the steam differential pressure, the rigidity of the circumferential direction is reduced by eliminating the inner ring, and there is a problem that it is easy to collapse. By providing the self-restraining means as described above, the above-described problems can be effectively solved.

  When fitting the metal linear pieces 9a and 9b into the open grooves 8a and 8b, the opening edges of the open grooves 8a and 8b are caulked, or the linear pieces 9a and 9b are made of a material or shape having a large linear expansion coefficient. When the temperature rises using a memory alloy or the like, it is preferable that the memory alloy is fitted into the open grooves 8a and 8b so as not to come out.

  FIGS. 2A and 2B are structural explanatory views of a turbine vane structure showing Embodiment 2 of the present invention, in which FIG. 2A is a front view of the main part and FIG. 2B is a perspective view of the main part.

  As a self-restraining means in the first embodiment, the steps (radial contact surfaces) 4a and 4b that are alternately provided between the circumferentially opposed (contact) surfaces of the inner shrouds 4 of the adjacent nozzle blades 2 are provided on the entire surface. This is an example of contact. That is, between the adjacent nozzle blades 2, the upward step 4a of one inner shroud 4 is aligned with the downward step 4b of the other inner shroud 4. Since the other configuration is the same as that of the first embodiment, the same members as those in FIG.

  According to this, when the nozzle blade 2 falls down, self-restraint with respect to the circumferential direction and the rotor axial direction is caused by the contact and friction in the circumferential direction and the radial direction of the adjacent nozzle blade 2 with the inner shroud 4. Thus, it is possible to reduce the collapse of the nozzle blade 2 and to prevent the nozzle blade 2 from being damaged. In this embodiment, there is an effect even when there is a gap in the circumferential direction only by contact in the radial direction.

  FIG. 3 is a front view of an essential part of a turbine stationary blade structure showing Embodiment 3 of the present invention, and FIG. 4 is a structure explanatory view of each modification.

  As a self-restraining means in the first embodiment, a bolt (not shown) is used on the end surface of the inner shroud 4 of an arbitrary nozzle blade 2 located on the mating surface of the outer rings 1A and 1B divided in half. This is an example in which the caulking allowance 10a (10b) that can be tightened is provided as a separate body (or an integral body). Since the other configuration is the same as that of the first embodiment, the same members as those in FIG.

  In the above case, as shown in FIG. 4 (a), the inner shroud 4 of the nozzle blade 2 assembled as before may be simply provided with a caulking allowance 10a (10b), or FIG. 4 (b). As shown, the initial shapes of the nozzle blades 2 and the inner shroud 4 may be preliminarily inclined (twisted) by a few degrees so as to be aligned by tightening with bolts.

  According to this, contact / friction with the inner shroud 4 of the adjacent nozzle blade 2 occurs after assembly, and the rigidity in the circumferential direction is increased, and the fall of the nozzle blade 2 is reduced as in the first embodiment. In addition, damage to the nozzle blades 2 can be avoided in advance.

  FIG. 5 is a structural explanatory view of a turbine stationary blade structure showing Embodiment 4 of the present invention, where FIG. 5 (a) is a front view of the main part, and FIG. .

  This is because, as a self-restraining means in the first embodiment, two (or more than one) metal rod-like pieces 11 may be arranged in the radial direction between the opposing surfaces of the inner shrouds 4 of the adjacent nozzle blades 2. This is an example in which recessed portions 4c that can be driven are formed to face each other. Since the other configuration is the same as that of the first embodiment, the same members as those in FIG.

  According to this, contact / friction occurs between the rod-shaped piece 11 and the inner shroud 4 through the recess 4c, and the rigidity in the circumferential direction is increased, and the fall of the nozzle blade 2 is reduced as in the first embodiment. Thus, damage to the nozzle blades 2 can be avoided in advance.

  FIGS. 6A and 6B are structural explanatory views of a turbine vane structure showing Embodiment 5 of the present invention. FIG. 6A is a front view of the main part, and FIG. .

  As a self-restraining means in the first embodiment, one (or a plurality of) metal bar-like pieces 11 can be driven from the rotor axial direction between the opposing surfaces of the inner shrouds 4 of the adjacent nozzle blades 2. In this example, the recesses 4c are formed to face each other. Since the other configuration is the same as that of the first embodiment, the same members as those in FIG.

  According to this, as in the fourth embodiment, contact / friction between the rod-shaped piece 11 and the inner shroud 4 through the recess 4c is generated, and the rigidity in the circumferential direction is increased. It is possible to reduce the collapse of the nozzle blade 2 and to prevent the nozzle blade 2 from being damaged.

  FIG. 7 is a structural explanatory view of a turbine vane structure showing Embodiment 6 of the present invention. FIG. 7 (a) is a perspective view of the inner shroud connected, and FIG. 7 (b) is a perspective view of the inner shroud alone. .

  This is because, as a self-restraining means in the first embodiment, the fitting holes 12 formed so as to face each other on the opposing surfaces of the inner shroud 4 of the adjacent nozzle blade 2 are formed in the adjacent inner shroud 4 at the time of assembly. This is an example in which one (or a plurality of) shear keys 13 are inserted so as to straddle. Since other configurations are the same as those of the first embodiment, detailed description thereof is omitted here with reference to FIG.

  According to this, as in the fourth embodiment, contact / friction between the shear key 13 and the inner shroud 4 through the fitting hole 12 is generated, the rigidity in the circumferential direction is increased, and the shear of the shear key 13 is increased. Sawtooth deformation is prevented by the action, and the fall of the nozzle blade 2 can be reduced and the breakage of the nozzle blade 2 can be avoided as in the first embodiment.

  FIG. 8 is a view of the inner shroud as seen from the inside in the turbine vane structure showing Embodiment 7 of the present invention.

  This is an example in which a locking structure including a groove 14 and a protrusion 15 is provided between the opposing surfaces of the inner shrouds 4 of the adjacent nozzle blades 2 as self-restraining means in the first embodiment. In the illustrated example, the groove 14 and the protrusion 15 are reversed in the radial direction and two locking structures are provided. However, one or three or more locking structures may be provided. In the illustrated example, the depth of the locking structure is changed in the circumferential direction, but may be constant. Since other configurations are the same as those of the first embodiment, detailed description thereof is omitted here with reference to FIG.

  According to this, the adjacent inner shrouds 4 influence each other due to the locking structure, and the circumferential rigidity is increased. As in the first embodiment, the falling of the nozzle blade 2 is reduced, and the nozzle blade 2 Damage or the like can be avoided in advance.

  FIG. 9 is a front view of a main part of a turbine vane structure showing an eighth embodiment of the present invention.

  This is an example in which a plurality of (four and three in the illustrated example) nozzle blades 2 are integrally formed as self-restraining means in the first embodiment to form a spell blade. Since the other configuration is the same as that of the first embodiment, the same members as those in FIG.

  According to this, relative movement between the nozzle blades 2 is prevented and rigidity in the circumferential direction is enhanced, and sawtooth-shaped deformation in the circumferential direction and the rotor shaft direction is prevented. 2 can be reduced, and damage to the nozzle blades 2 can be avoided in advance.

  In this embodiment, since it is difficult to integrally form 180 °, a gap may be formed every several sheets. However, it is preferable to apply the other embodiments described above to the gap.

  Needless to say, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. For example, the embodiments can be implemented in combination as appropriate in addition to the embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS It is structural explanatory drawing of the turbine stationary blade structure which shows Example 1 of this invention, The figure (a) is a principal part front view, The figure (b) is A sectional view taken on the A arrow of the figure (a). FIG. 4 is a structural explanatory view of a turbine stationary blade structure showing Embodiment 2 of the present invention, in which FIG. (A) is a front view of relevant parts and (b) is a perspective view of relevant parts. It is a principal part front view of the turbine stationary blade structure which shows Example 3 of this invention. It is structure explanatory drawing of each modification. FIG. 4 is a structural explanatory view of a turbine stationary blade structure showing Embodiment 4 of the present invention, in which FIG. (A) is a front view of an essential part, and (b) is a view taken in the direction of arrow B in FIG. FIG. 6 is a structural explanatory view of a turbine stationary blade structure showing Embodiment 5 of the present invention, in which FIG. (A) is a front view of the main part, and FIG. FIG. 6 is a structural explanatory view of a turbine stationary blade structure showing Embodiment 6 of the present invention, in which FIG. (A) is a perspective view of an inner shroud connected, and FIG. (B) is a perspective view of an inner shroud alone. It is the figure which looked at the inner shroud in the turbine stationary blade structure which shows Example 7 of this invention from the inside. It is a principal part front view of the turbine stationary blade structure which shows Example 8 of this invention.

Explanation of symbols

1A, 1B Outer ring 2 Nozzle blade 3 Outer shroud 4 Inner shroud 4a, 4b Step 4c Recessed portion 5 Labyrinth seal 8a, 8b Open groove 9a, 9b Linear piece 10a, 10b Caulking allowance 11 Rod-like piece 12 Fitting hole 13 Shear key 14 Groove 15 protrusions

Claims (8)

In the turbine stationary blade structure including an outer shroud for implanting an outer ring at one end of each nozzle blade and an inner shroud capable of mounting a seal material interposed in a gap with the turbine rotor at the other end,
A turbine stationary blade structure characterized in that self-restraining means for improving the circumferential rigidity of the inner shroud in each nozzle blade is provided.   The turbine stationary blade structure according to claim 1, wherein the self-restraining means is provided in such a manner that a staggered step is provided between opposing surfaces of inner shrouds of adjacent nozzle blades so as to be brought into full contact with each other.   As the self-restraining means, an open groove penetrating in the circumferential direction is formed on the side surface of the inner shroud so as to communicate with at least the plurality of nozzle blades, and spans at least the plurality of nozzle blades into the open grooves. The turbine stationary blade structure according to claim 1, wherein a linear piece having a long length is fitted.   The self-restraining means is provided with a caulking allowance that can be tightened at the time of assembling the outer ring on the end surface of the inner shroud of the nozzle blade located on the mating surface of the outer ring divided in a plurality in the circumferential direction. The turbine stationary blade structure according to claim 1.   2. The self-restraining means is characterized in that a concave part capable of being driven in a radial direction and / or an axial direction is formed opposite to each other between opposing faces of inner shrouds of adjacent nozzle blades. The turbine stationary blade structure described.   As a self-restraining means, a shear key is inserted into a fitting hole formed so as to face each other on the opposing surfaces of the inner shrouds of adjacent nozzle blades so as to straddle the adjacent inner shroud during assembly. The turbine stationary blade structure according to claim 1, wherein:   2. The turbine stationary blade structure according to claim 1, wherein a locking structure including a groove and a protrusion is provided between the opposing surfaces of the inner shrouds of adjacent nozzle blades as the self-restraining means.   The turbine stationary blade structure according to claim 1, wherein a plurality of nozzle blades are integrally formed as the self-restraining means to form a spell blade.

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