Nozzle ring, nozzle diaphragm, steam turbine, nozzle diaphragm assembling method, steam turbine assembling method, and steam turbine disassembly method

Abstract

To easily and reliably manufacture a nozzle ring having high accuracy.SOLUTION: A nozzle module constituting a nozzle ring which can be arranged between an inner ring extending in a circumferential direction around a center axis and an outer ring arranged on a radially outer side with respect to the inner ring around the center axis and extending in the circumferential direction, comprises: a nozzle body being of an airfoil shape in cross section and extending in a radial direction; and platform members integrally connected to radial ends of the nozzle body. The platform members each have a first portion which is formed on a first side in an axial direction in which the center axis extends when viewed from the radial direction, and has a pair of first side faces extending in the axial direction, and a second portion which is formed so as to extend to a second side in the axial direction with respect to the first portion when viewed from the radial direction, and has a second side face extending obliquely with respect to the first side face.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a nozzle ring The present invention relates to a nozzle diaphragm, a steam turbine, a method for assembling a nozzle diaphragm, a method for assembling a steam turbine, and a method for disassembling a steam turbine. [Background technology]

[0002] A steam turbine mainly comprises a rotor that rotates around an axis and a casing that covers the rotor from the outside and forms a steam flow path between the rotor and the rotor. The rotor has a rotating shaft extending along the axis and a plurality of moving blades arranged on the outer surface of the rotating shaft. A nozzle diaphragm having a plurality of stationary vanes (nozzles) arranged alternately with the plurality of moving blades in the axial direction is arranged on the inner surface of the casing.

[0003] A specific example of such a nozzle diaphragm is known from Patent Document 1. The nozzle diaphragm described in Patent Document 1 includes a nozzle having an inner shroud in contact with the outer peripheral surface of an inner ring and a nozzle body having an integral structure that protrudes radially outward from the inner shroud, and an outer shroud ring having through holes that penetrate radially so that the outer peripheral ends of the nozzle bodies can be inserted therethrough. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-84768 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the configuration described in Patent Document 1, the outer peripheral end of the nozzle body needs to be inserted through the through-hole in the outer shroud ring. Therefore, particularly in a bow nozzle in which the nozzle body is curved three-dimensionally, high machining accuracy is required for the through-holes formed in the nozzle body and the outer shroud ring. Furthermore, assembling the nozzle diaphragm requires a high level of skill to align the nozzle bodies in an annular shape, and the workers who perform the assembly work are limited to highly skilled personnel. As a result, manufacturing the nozzle diaphragm involves problems of time and cost.

[0006] The present disclosure has been made to solve the above-mentioned problems, and provides a nozzle ring that can be easily and reliably manufactured with high precision. ring The present invention aims to provide a nozzle ring, a steam turbine, a method for assembling a nozzle ring, a method for assembling a steam turbine, and a method for disassembling a steam turbine. [Means for solving the problem]

[0007] In order to solve the above problems, the present disclosure Nozzle Ring The nozzle ring can be disposed between an inner ring extending in a circumferential direction around a central axis and an outer ring disposed radially outward from the inner ring around the central axis and extending in the circumferential direction. Gu There was, an upper half nozzle ring disposed vertically above the central axis and formed in a semicircular ring shape centered on the central axis; and a lower half nozzle ring disposed vertically below the central axis and formed in a semicircular ring shape centered on the central axis, wherein the upper half nozzle ring and the lower half nozzle ring each have a plurality of nozzle modules arranged side by side in the circumferential direction, and the nozzle module comprises: The nozzle body has a cross section that forms an airfoil shape and extends in the radial direction, and platform members that are integrally connected to end portions of the nozzle body in the radial direction, wherein the platform member has a first portion that is formed on a first side in the axial direction in which the central axis extends and has a pair of first side surfaces that extend in the axial direction when viewed from the radial direction, and a second portion that is formed to extend on a second side in the axial direction relative to the first portion and has a second side surface that extends at an angle to the first side surfaces. The upper half nozzle ring and the lower half nozzle ring include a first nozzle module, a second nozzle module, a third nozzle module, and a fourth nozzle module as the plurality of nozzle modules, and the first nozzle module, the second nozzle module, the third nozzle module, and the fourth nozzle module each have a different configuration of the platform member, and the second nozzle module and the third nozzle module are arranged at a first end of the upper half nozzle ring and the lower half nozzle ring in the circumferential direction, and the upper half nozzle ring and the lower half nozzle ring have a second end of the upper half nozzle ring and the lower half nozzle ring in the circumferential direction. the fourth nozzle module is disposed, and in the upper half-nozzle ring and the lower half-nozzle ring, a plurality of the first nozzle modules are disposed between the second nozzle module and the third nozzle module and the fourth nozzle module in the circumferential direction, the upper half-nozzle ring has two upper half-ring divided surfaces which are horizontal surfaces facing downward in the vertical direction, and the lower half-nozzle ring has two lower half-ring divided surfaces which are horizontal surfaces facing upward in the vertical direction, one of the upper half-ring divided surfaces and the lower half-ring divided surfaces being formed by the second nozzle module and the third nozzle module, and the other being formed by the fourth nozzle module. do.

[0008] The nozzle diaphragm according to the present disclosure is a nozzle diaphragm as described above. ringan inner ring arranged radially inward relative to the nozzle module and extending in the circumferential direction, and an outer ring arranged radially outward relative to the nozzle module and extending in the circumferential direction, and multiple nozzle modules are arranged side by side between the inner ring and the outer ring to form a nozzle ring.

[0009] The steam turbine of the present disclosure comprises a nozzle diaphragm as described above, a cylindrical casing arranged radially outward from the nozzle diaphragm and extending in the axial direction, and a rotor arranged rotatably around the central axis relative to the nozzle diaphragm and the casing and housed in the casing.

[0010] The nozzle ring assembly method according to the present disclosure is a method for assembling a nozzle diaphragm as described above, and includes the steps of preparing the inner ring, the outer ring, and a plurality of the nozzle modules, positioning the inner ring, positioning the nozzle module radially outward from the inner ring, positioning the outer ring radially outward from the plurality of the nozzle modules, welding the inner ring to the platform member, and welding the outer ring to the platform member.

[0011] A method of assembling a steam turbine according to the present disclosure includes the steps of providing a casing and assembling a nozzle diaphragm as described above within the casing.

[0012] A method of disassembling a steam turbine according to the present disclosure includes the steps of opening a portion of a casing and removing the nozzle diaphragm described above from the casing. [Effects of the Invention]

[0013] Nozzle of the present disclosure ring According to the nozzle diaphragm, steam turbine, nozzle diaphragm assembling method, steam turbine assembling method, and steam turbine disassembly method, a nozzle ring with high precision can be manufactured easily and reliably. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram illustrating a schematic configuration of a steam turbine according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a view of the nozzle diaphragm of the steam turbine as viewed from the axial direction. [Figure 3] FIG. 3 is a cross-sectional view taken along the line A-A in FIG. 2. [Figure 4] 3 is a development view of inner platform members of a plurality of nozzle modules that make up the nozzle diaphragm of FIG. 2, as viewed from the inside in the radial direction. [Figure 5] 3 is a development view of outer platform members of a plurality of nozzle modules that make up the nozzle diaphragm of FIG. 2, as viewed from the outside in the radial direction. [Figure 6] 5 is a radially inner view of an inner platform member of a first nozzle module of the plurality of nozzle modules of FIG. 4. FIG. [Figure 7] 5 is a view of an outer platform member of a first nozzle module of the plurality of nozzle modules of FIG. 4, viewed from the radially outer side. [Figure 8] 5 is a view of the inner platform members of the second and third nozzle modules of the plurality of nozzle modules of FIG. 4, as viewed from the radially inner side. FIG. [Figure 9] 5 is a view of the outer platform members of the second and third nozzle modules of the plurality of nozzle modules of FIG. 4, viewed from the outside in the radial direction. FIG. [Figure 10] 5 is a view of an inner platform member of a fourth nozzle module of the plurality of nozzle modules of FIG. 4, viewed from the inside in the radial direction. FIG. [Figure 11] 5 is a view of an outer platform member of a fourth nozzle module among the plurality of nozzle modules of FIG. 4, viewed from the outside in the radial direction. FIG. [Figure 12] 1 is a flowchart showing the steps of a method for assembling a noise diaphragm according to an embodiment of the present disclosure. [Figure 13] 10A to 10C are diagrams illustrating a step of placing an inner ring in a method of assembling a noise diaphragm according to an embodiment of the present disclosure. [Figure 14] 10A and 10B are diagrams illustrating a step of placing a nozzle module in a method of assembling a noise diaphragm according to an embodiment of the present disclosure. [Figure 15] 10A to 10C are diagrams illustrating a step of placing an outer ring in a method of assembling a noise diaphragm according to an embodiment of the present disclosure. [Figure 16] 3 is a flowchart illustrating steps in a method for assembling a steam turbine according to an embodiment of the present disclosure. [Figure 17] 1A to 1C are diagrams illustrating a step of preparing a casing in a method of assembling a steam turbine according to an embodiment of the present disclosure, and a step of removing a nozzle diaphragm in a method of disassembling a steam turbine according to an embodiment of the present disclosure. [Figure 18] 1A to 1C are diagrams illustrating a process of installing a nozzle diaphragm in a method of assembling a steam turbine according to an embodiment of the present disclosure, and a process of opening a portion of a casing in a method of disassembling a steam turbine according to an embodiment of the present disclosure. [Figure 19] 1 is a flowchart illustrating steps in a method for disassembling a steam turbine according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments for carrying out a nozzle module, a nozzle diaphragm, a steam turbine, a method for assembling a nozzle diaphragm, a method for assembling a steam turbine, and a method for disassembling a steam turbine according to the present disclosure will be described with reference to the accompanying drawings. However, the present disclosure is not limited to only these embodiments.

[0016] (Steam turbine configuration) The steam turbine 1 converts the energy of steam into rotational energy to rotate it. As shown in FIG. 1, the steam turbine 1 includes a casing 2, a rotor 3, and a nozzle diaphragm 5.

[0017] (Casing configuration) The casing 2 is formed in a cylindrical shape extending in the axial direction Da around the central axis O of the rotor 3. The casing 2 has a steam inlet 27 that introduces steam into the casing 2 and a steam outlet 28 that discharges steam from inside the casing 2 to the outside. In this embodiment, the casing 2 has an upper half casing 21 arranged Dvu above the central axis O of the rotor 3 in the vertical direction Dv, and a lower half casing 22 arranged Dvd below.

[0018] The upper half casing 21 extends in the circumferential direction Dc. A cross section of the upper half casing 21 perpendicular to the central axis O has a semicircular ring shape centered on the central axis O. The upper half casing 21 opens downward Dvd in the vertical direction Dv so as to be able to accommodate the rotor 3 and the nozzle diaphragm 5. The upper half casing 21 has upper half casing dividing surfaces (not shown) at both ends in the circumferential direction Dc.

[0019] The lower half casing 22 extends in the circumferential direction Dc. A cross section of the lower half casing 22 perpendicular to the central axis O has a semicircular ring shape centered on the central axis O. The inner diameter of the lower half casing 22 is the same as the inner diameter of the upper half casing 21. The lower half casing 22 opens toward an upper side Dvu in the vertical direction Dv so as to accommodate the rotor 3 and the nozzle diaphragm 5. The lower half casing 22 has lower half casing dividing surfaces (not shown) at both ends in the circumferential direction Dc. The upper half casing 21 is placed above the lower half casing 22 at a position Dvu above the vertical direction Dv. The upper half casing 21 and the lower half casing 22 are fixed together with fastening members such as bolts (not shown) with the upper half casing dividing surface and the lower half casing dividing surface in contact with each other. In this manner, the casing 2 is formed.

[0020] (Rotor configuration) The rotor 3 includes a rotating shaft 31 and rotor blades 32. The rotor 3 is covered by a casing 2 from the outside Dro in the radial direction Dr about the central axis O.

[0021] The rotating shaft 31 has a cylindrical shape extending along the axial direction Da. Both end portions 31a and 31b of the rotating shaft 31 in the axial direction Da are supported by a first bearing 33A and a second bearing 33B, respectively, so as to be rotatable around a central axis O. The rotating shaft 31 is housed inside the casing 2.

[0022] The rotor blades 32 are arranged in multiple stages at intervals in the axial direction Da of the rotary shaft 31. Each rotor blade 32 extends from the outer circumferential surface of the rotary shaft 31 toward the outside Dro in the radial direction Dr.

[0023] (Nozzle diaphragm configuration) A plurality of nozzle diaphragms 5 are arranged at intervals in the axial direction Da inside the casing 2. Each nozzle diaphragm 5 is arranged on the outer side Dro in the radial direction Dr of the rotating shaft 31. The nozzle diaphragms 5 are arranged alternately with the rotor blades 32 of each stage in the axial direction Da. Each nozzle diaphragm 5 is annular about the central axis O. As shown in FIGS. 2 and 3 , the nozzle diaphragm 5 of this embodiment includes an inner ring 6, an outer ring 7, and a nozzle ring 51.

[0024] The inner ring 6 is disposed on the outer side Dro in the radial direction Dr of the rotating shaft 31 (see FIG. 1). As shown in FIG. 2, the inner ring 6 extends in the circumferential direction Dc. The inner ring 6 has an annular shape centered on the central axis O. The inner ring 6 is disposed on the inner side Dri in the radial direction Dr of the nozzle ring 51. The inner ring 6 has an upper half inner ring member 61 disposed above Dvu in the vertical direction Dv with respect to the central axis O of the rotor 3 as the reference, and a lower half inner ring member 62 disposed below Dvd.

[0025] The upper half inner ring member 61 extends in the circumferential direction Dc. The upper half inner ring member 61 has a semicircular ring shape centered on the central axis O. The upper half inner ring member 61 opens facing downward Dvd in the vertical direction Dv. The lower half inner ring member 62 extends in the circumferential direction Dc. The lower half inner ring member 62 has a semicircular ring shape centered on the central axis O. The inner diameter of the lower half inner ring member 62 is formed to be the same size as the inner diameter of the upper half inner ring member 61. The lower half inner ring member 62 opens facing upward Dvu in the vertical direction Dv. The upper half inner ring member 61 is placed above Dvu in the vertical direction Dv with respect to the lower half inner ring member 62. Both end portions 61a and 61b of the upper-half inner ring member 61 in the circumferential direction Dc and both end portions 62a and 62b of the lower-half inner ring member 62 in the circumferential direction Dc are fixed together with fastening members such as bolts (not shown), thereby forming the inner ring 6.

[0026] The outer ring 7 is disposed on the inner side Dri in the radial direction Dr of the casing 2. The outer ring 7 extends in the circumferential direction Dc. The outer ring 7 has an annular shape centered on the central axis O. The outer ring 7 is disposed on the outer side Dro in the radial direction Dr of the nozzle ring 51. The outer ring 7 has an upper half outer ring member 71 disposed above Dvu in the vertical direction Dv with respect to the central axis O of the rotor 3 as the reference, and a lower half outer ring member 72 disposed below Dvd.

[0027] The upper half outer ring member 71 extends in the circumferential direction Dc. The upper half outer ring member 71 has a semicircular ring shape centered on the central axis O. The upper half outer ring member 71 opens facing downward Dvd in the vertical direction Dv. The lower half outer ring member 72 extends in the circumferential direction Dc. The lower half outer ring member 72 has a semicircular ring shape centered on the central axis O. The inner diameter of the lower half outer ring member 72 is formed to be the same size as the inner diameter of the upper half outer ring member 71. The lower half outer ring member 72 opens facing upward Dvu in the vertical direction Dv. The upper half outer ring member 71 is placed above Dvu in the vertical direction Dv with respect to the lower half outer ring member 72. Both end portions 71a, 71b of the upper-half outer ring member 71 in the circumferential direction Dc and both end portions 72a, 72b of the lower-half outer ring member 72 in the circumferential direction Dc are fixed together with fastening members such as bolts (not shown), thereby forming the outer ring 7.

[0028] (Nozzle ring configuration) The nozzle ring 51 is disposed between the inner ring 6 and the outer ring 7. The nozzle ring 51 as a whole has an annular shape centered on the central axis O. The nozzle ring 51 is disposed on the outer side Dro in the radial direction Dr relative to the inner ring 6 and on the inner side Dri in the radial direction Dr relative to the outer ring 7. The nozzle ring 51 is composed of a plurality of nozzle modules 52 disposed side by side in the circumferential direction Dc. The nozzle ring 51 has an upper half nozzle ring 511 disposed above Dvu in the vertical direction Dv with respect to the central axis O, and a lower half nozzle ring 512 disposed below Dvd.

[0029] The upper half nozzle ring 511 extends in the circumferential direction Dc. The upper half nozzle ring 511 has a semicircular ring shape centered on the central axis O. The upper half nozzle ring 511 opens toward the downward direction Dvd in the vertical direction Dv. The upper half nozzle ring 511 has upper half ring divided surfaces 511f on both ends in the circumferential direction Dc. The upper half ring divided surfaces 511f of the upper half nozzle ring 511 are horizontal surfaces facing downward direction Dvd in the vertical direction Dv.

[0030] The lower half nozzle ring 512 extends in the circumferential direction Dc. The lower half nozzle ring 512 has a semicircular ring shape centered on the central axis O. The outer and inner diameters of the lower half nozzle ring 512 are the same as those of the upper half nozzle ring 511. The lower half nozzle ring 512 opens toward the upward direction Dvu in the vertical direction Dv. The lower half nozzle ring 512 has lower half ring divided surfaces 512f at both ends in the circumferential direction Dc. The lower half ring divided surfaces 512f are horizontal surfaces facing the upward direction Dvu in the vertical direction Dv. The upper half nozzle ring 511 is placed above the lower half nozzle ring 512 at the upward direction Dvu in the vertical direction Dv. The upper half nozzle ring 511 and the lower half nozzle ring 512 are arranged with the upper half ring divided surface 511f and the lower half ring divided surface 512f in contact with each other.

[0031] The upper half-nozzle ring 511 and the lower half-nozzle ring 512 are each composed of a plurality of nozzle modules 52 arranged side by side in the circumferential direction Dc. As shown in Fig. 4 and Fig. 5, the upper half-nozzle ring 511 and the lower half-nozzle ring 512 each include a plurality of nozzle modules 52, for example, a plurality of types of nozzle modules 52A to 52D. Specifically, the upper half-nozzle ring 511 and the lower half-nozzle ring 512 each include a first nozzle module 52A, a second nozzle module 52B, a third nozzle module 52C, and a fourth nozzle module 52D as the nozzle modules 52. The second nozzle module 52B, the third nozzle module 52C, and the fourth nozzle module 52D are arranged at both ends of the upper half-nozzle ring 511 and the lower half-nozzle ring 512 in the circumferential direction Dc, in regions facing the upper half-ring divided surface 511f and the lower half-ring divided surface 512f. In the area other than the areas where the second nozzle module 52B, the third nozzle module 52C, and the fourth nozzle module 52D are arranged, a plurality of first nozzle modules 52A of the same shape are arranged.

[0032] (Nozzle module configuration) As shown in FIGS. 2 and 3, the nozzle module 52 constituting the nozzle ring 51 (upper half nozzle ring 511, lower half nozzle ring 512) includes a nozzle body 53 and a platform member .

[0033] 4 and 5 , the nozzle body 53 extends in the radial direction Dr and has a blade-shaped cross section when viewed in the radial direction Dr. In the nozzle body 53, an end portion 53a forming a leading edge of the nozzle body 53 on a first side Da1 in the axial direction Da when viewed in the radial direction Dr faces the first side Da1 in the axial direction Da. In the nozzle body 53, an end portion 53b forming a trailing edge of the nozzle body 53 on a second side Da2 in the axial direction Da when viewed in the radial direction Dr faces a direction inclined toward the first side Dc1 in the circumferential direction Dc with respect to the axial direction Da. Here, the first side Da1 in the axial direction Da is the upstream side in the flow direction of steam in the steam turbine 1, and is the side of the casing 2 where the steam inlet 27 is located relative to the steam outlet 28 in the axial direction Da. The second side Da2 in the axial direction Da is the downstream side in the steam flow direction in the steam turbine 1, and is the side of the casing 2 where the steam outlet 28 is arranged relative to the steam inlet 27 in the axial direction Da. The nozzle body 53 is curved so as to be recessed toward the second side Dc2 in the circumferential direction Dc between the end portion 53a and the end portion 53b. The nozzle body 53 is formed in a three-dimensional shape such that the cross section gradually changes from the inner side Dri to the outer side Dro in the radial direction Dr.

[0034] The platform member 54 is integrally connected to both end portions of the nozzle body 53 in the radial direction Dr. The platform member 54 has an inner circumferential surface 54f connected to the nozzle body 53, and an outer circumferential surface 54g facing the opposite side to the inner circumferential surface 54f in the radial direction Dr. As shown in FIGS. 2 to 5, the platform member 54 includes an inner platform member 55 and an outer platform member 56.

[0035] As shown in FIG. 3 , the inner platform member 55 is integrally connected to an inner peripheral end portion 53i of the nozzle body 53 on the inner side Dri in the radial direction Dr. The inner platform member 55 has an inner inner peripheral surface 55f facing the outer side Dro in the radial direction Dr and an inner outer peripheral surface 55g facing the opposite side from the inner inner peripheral surface 55f in the radial direction Dr. The inner inner peripheral surface 55f is the inner peripheral surface 54f connected to the nozzle body 53. The inner outer peripheral surface 55g is the outer peripheral surface 54g facing the inner side Dri in the radial direction Dr. The inner outer peripheral surface 55g extends in the circumferential direction Dc and is formed parallel to the central axis O when viewed from the circumferential direction Dc. The inner outer peripheral surface 55g is joined to the inner ring 6 by, for example, electron beam welding. That is, the nozzle diaphragm 5 has an inner weld 58 between the inner ring 6 and the inner platform member 55. In addition, in the inner platform member 55, in order to form the inner weld 58, the distance between the inner inner peripheral surface 55f and the inner outer peripheral surface 55g in the radial direction Dr is set to a length that allows electron beam welding (EBW) (e.g., 10 mm or more).

[0036] Furthermore, as shown in FIG. 6, the inner platform member 55 has, when viewed in the radial direction Dr, an inner first portion (first portion) 551 formed on a first side Da1 in the axial direction Da, and an inner second portion (second portion) 552 formed on a second side Da2 in the axial direction Da.

[0037] As shown in FIG. 3 , the outer platform member 56 is integrally connected to an outer peripheral end portion 53o of the nozzle body 53 on the outer side Dro in the radial direction Dr. The outer platform member 56 has an outer inner peripheral surface 56f facing the inner side Dri in the radial direction Dr and an outer outer peripheral surface 56g facing the opposite side of the outer inner peripheral surface 56f in the radial direction Dr. The outer inner peripheral surface 56f is the inner peripheral surface 54f connected to the nozzle body 53. The outer outer peripheral surface 56g is the outer peripheral surface 54g facing the outer side Dro in the radial direction Dr. The outer inner peripheral surface 56f is inclined from the first side Da1 to the second side Da2 in the axial direction Da toward the outer side Dro in the radial direction Dr. The outer outer peripheral surface 56g extends in the circumferential direction Dc and is parallel to the central axis O when viewed from the circumferential direction Dc. The outer outer peripheral surface 56g is joined to the outer ring 7 by, for example, electron beam welding. That is, the nozzle diaphragm 5 has an outer weld 59 between the outer ring 7 and the outer platform member 56. In order to form the outer weld 59, the distance between the outer inner circumferential surface 56f and the outer outer circumferential surface 56g in the radial direction Dr of the outer platform member 56 is set to a length (e.g., 10 mm or more) that allows electron beam welding (EBW).

[0038] 7, the outer platform member 56 has an outer first portion (first portion) 561 formed on a first side Da1 in the axial direction Da, and an outer second portion (second portion) 562 formed on a second side Da2 in the axial direction Da, when viewed in the radial direction Dr. In this embodiment, the inner first portion 551 and the outer first portion 561, and the inner second portion 552 and the outer second portion 562 are formed in different shapes. More specifically, the inner first portion 551 and the outer first portion 561 are different in size, and the inner second portion 552 and the outer second portion 562 are different in size.

[0039] Here, the structure of each of the nozzle modules 52 will be described in more detail, starting with the first nozzle module 52A to the fourth nozzle module 52D. As shown in Fig. 6, the inner platform member 55A of the first nozzle module 52A integrally includes a first inner portion 551A and a second inner portion 552A.

[0040] The inner first portion 551A has an inner front surface (front surface) 551f and a pair of inner first side surfaces (first side surfaces) 551a and 551b when viewed from the radial direction Dr. The inner front surface 551f extends in the circumferential direction Dc when viewed from the radial direction Dr. The inner front surface 551f is formed to face the first side Da1 in the axial direction Da. The inner front surface 551f intersects with the inner inner circumferential surface 55f. The inner front surface 551f is perpendicular to (intersects with) the inner outer circumferential surface 55g.

[0041] The pair of inner first side surfaces 551a and 551b extend in the axial direction Da so as to be perpendicular to the inner front surface 551f when viewed in the radial direction Dr. The pair of inner first side surfaces 551a and 551b extend from both ends of the inner front surface 551f in the circumferential direction Dc toward the second side Da2 in the axial direction Da. The pair of inner first side surfaces 551a and 551b extend parallel to each other when viewed in the radial direction Dr. The pair of inner first side surfaces 551a and 551b are surfaces facing opposite directions in the circumferential direction Dc. The inner first side surfaces 551a and 551b intersect with the inner inner circumferential surface 55f. The inner first side surfaces 551a and 551b are perpendicular to (intersect with) the inner outer circumferential surface 55g.

[0042] The inner second portion 552A is formed to extend integrally with the inner first portion 551A on the second side Da2 in the axial direction Da. When viewed from the radial direction Dr, the inner second portion 552A has an inner rear surface (rear surface) 552r and a pair of inner second side surfaces (second side surfaces) 552a and 552b.

[0043] The inner rear surface 552r extends in the circumferential direction Dc when viewed from the radial direction Dr. The inner rear surface 552r is formed to face the second side Da2 in the axial direction Da so as to face away from the inner front surface 551f. The inner front surface 551f intersects with the inner inner circumferential surface 55f. The inner front surface 551f is perpendicular to (intersects with) the inner outer circumferential surface 55g.

[0044] The pair of inner second side surfaces 552a and 552b extend at an incline relative to the pair of inner first side surfaces 551a and 551b when viewed from the radial direction Dr. The pair of inner second side surfaces 552a and 552b are inclined toward the first side surface Dc1 in the circumferential direction Dc as they extend from the pair of inner first side surfaces 551a and 551b toward the second side surface Da2 in the axial direction Da. The inner second side surface 552a is connected to the inner first side surface 551a, and the inner second side surface 552b is connected to the inner first side surface 551b. The pair of inner second side surfaces 552a and 552b extend parallel to each other when viewed from the radial direction Dr. The pair of inner second side surfaces 552a and 552b are surfaces facing in opposite directions in a direction intersecting the circumferential direction Dc and the axial direction Da. The inner first side surfaces 551a and 551b intersect with the inner inner circumferential surface 55f. The inner first side surfaces 551a and 551b are perpendicular to (intersect with) the inner outer peripheral surface 55g. When viewed from the radial direction Dr, the distance L1 between the pair of inner first side surfaces 551a and 551b is equal to the distance L2 between the pair of inner second side surfaces 552a and 552b. Here, the distance L1 is the distance in a direction perpendicular to the inner first side surfaces 551a and 551b, and is the distance between the inner first side surfaces 551a and 551b in the circumferential direction Dc. Furthermore, the distance L2 is the distance in a direction perpendicular to the inner second side surfaces 552a and 552b, and is the distance between the inner second side surfaces 552a and 552b in a direction intersecting the circumferential direction Dc and the axial direction Da.

[0045] The inner platform member 55A of the first nozzle module 52A has inner curved surfaces (curved surfaces) 553a and 553b on a first side Da1 and a second side Da2 in the circumferential direction Dc when viewed in the radial direction Dr. The inner curved surface 553a curves and smoothly connects between the inner first side surface 551a and the inner second side surface 552a on the first side Da1 in the circumferential direction Dc of the inner platform member 55A. The inner curved surface 553a is a concave surface when viewed in the radial direction Dr. The inner curved surface 553b curves and smoothly connects between the inner first side surface 551b and the inner second side surface 552b on the second side Da2 in the circumferential direction Dc of the inner platform member 55A. The inner curved surface 553b is a convex surface when viewed in the radial direction Dr. The inner curved surface 553b is formed in a shape that overlaps the inner curved surface 553a without any gap when viewed from the radial direction Dr.

[0046] The inner platform member 55A of the first nozzle module 52A is connected to the entire inner circumferential end 53i of the nozzle body 53 when viewed in the radial direction Dr. The inner first portion 551A is arranged to overlap with the end 53a of the nozzle body 53 on the first side Da1 in the axial direction Da when viewed in the radial direction Dr. The inner second portion 552A is arranged to overlap with the end 53b of the nozzle body 53 on the second side Da2 in the axial direction Da when viewed in the radial direction Dr.

[0047] As shown in FIG. 7, in the first nozzle module 52A, the outer platform member 56A integrally includes an outer first portion 561A and an outer second portion 562A.

[0048] The outer first portion 561A has an outer front surface (front face) 561f and a pair of outer first side surfaces 561a and 561b when viewed in the radial direction Dr.

[0049] The outer front surface 561f extends in the circumferential direction Dc when viewed from the radial direction Dr. The outer front surface 561f is formed to face the first side Da1 in the axial direction Da. As shown in FIG. 3, the outer front surface 561f is disposed at the same position as the inner front surface 551f of the inner platform member 55 in the axial direction Da. The outer front surface 561f intersects with the outer inner circumferential surface 56f. The outer front surface 561f is perpendicular to (intersects with) the outer outer circumferential surface 56g.

[0050] As shown in FIG. 7 , the pair of outer first side surfaces 561a and 561b extend in the axial direction Da so as to be perpendicular to the outer front surface 561f when viewed in the radial direction Dr. The pair of outer first side surfaces 561a and 561b extend from both ends of the outer front surface 561f in the circumferential direction Dc toward the second side Da2 in the axial direction Da. The pair of outer first side surfaces 561a and 561b extend parallel to each other when viewed in the radial direction Dr. The pair of outer first side surfaces 561a and 561b are surfaces facing opposite directions in the circumferential direction Dc. The outer first side surfaces 561a and 561b intersect with the outer inner circumferential surface 56f. The outer first side surfaces 561a and 561b are perpendicular to (intersect with) the outer outer peripheral surface 56g. The distance L3 between the pair of outer first side surfaces 561a and 561b may be the same as or different from the distance L1 between the pair of inner first side surfaces 551a and 551b of the inner platform member 55A. That is, the outer first portion 561A may have the same size (shape) as or a different size (shape) from the inner first portion 551A. Here, the distance L3 is the distance in a direction perpendicular to the outer first side surfaces 561a and 561b, and is the distance between the outer first side surfaces 561a and 561b in the circumferential direction Dc.

[0051] The outer second portion 562A is formed to extend integrally with the outer first portion 561A on the second side Da2 in the axial direction Da. When viewed from the radial direction Dr, the outer second portion 562A has an outer rear surface 562r and a pair of outer second side surfaces (second side surfaces) 562a and 562b.

[0052] The outer rear surface 562r extends in the circumferential direction Dc when viewed from the radial direction Dr. The outer rear surface 562r is formed to face the second side Da2 in the axial direction Da so as to face away from the outer front surface 561f. The outer rear surface 562r intersects with the outer inner circumferential surface 56f. The outer rear surface 562r is perpendicular to (intersects with) the outer outer circumferential surface 56g.

[0053] The pair of outer second side surfaces 562a and 562b extend at an incline relative to the pair of outer first side surfaces 561a and 561b when viewed from the radial direction Dr. The pair of outer second side surfaces 562a and 562b are inclined toward the first side surface Dc1 in the circumferential direction Dc as they extend from the pair of outer first side surfaces 561a and 561b toward the second side surface Da2 in the axial direction Da. The outer second side surface 562a is connected to the outer first side surface 561a, and the outer second side surface 562b is connected to the outer first side surface 561b. The pair of outer second side surfaces 562a and 562b extend parallel to each other when viewed from the radial direction Dr. The pair of outer second side surfaces 562a and 562b are surfaces facing in opposite directions in a direction intersecting the circumferential direction Dc and the axial direction Da. The outer first side surfaces 561a and 561b intersect with the outer inner circumferential surface 56f. The outer first side surfaces 561a and 561b are perpendicular to (intersect with) the outer outer peripheral surface 56g. When viewed from the radial direction Dr, the distance L3 between the pair of outer first side surfaces 561a and 561b is equal to the distance L4 between the pair of outer second side surfaces 562a and 562b. The distance L4 between the pair of outer second side surfaces 562a and 562b is greater than the distance L2 between the pair of inner second side surfaces 552a and 552b of the inner platform member 55A. Here, the distance L4 is the distance in a direction perpendicular to the outer second side surfaces 562a and 562b, and is the distance between the outer second side surfaces 562a and 562b in a direction intersecting the circumferential direction Dc and the axial direction Da.

[0054] Note that the distance L4 may be different from or the same as the distance L2. Furthermore, the inclination of the pair of outer second side surfaces 562a and 562b may be different from or the same as the inclination of the pair of inner second side surfaces 552a and 552b of the inner platform member 55A. In other words, the outer first portion 561A may have the same size (shape) as the inner first portion 551A or may have a different size (shape).

[0055] The outer platform member 56A of the first nozzle module 52A has outer curved surfaces (curved surfaces) 563a and 563b on a first side Da1 and a second side Da2 in the circumferential direction Dc when viewed from the radial direction Dr. The outer curved surface 563a curves and smoothly connects between the outer first side surface 561a and the outer second side surface 562a on the first side Da1 in the circumferential direction Dc of the outer platform member 56A. The outer curved surface 563a is a concave surface when viewed from the radial direction Dr. The outer curved surface 563b curves and smoothly connects between the outer first side surface 561b and the outer second side surface 562b on the second side Da2 in the circumferential direction Dc of the outer platform member 56A. The outer curved surface 563b is a concave surface when viewed from the radial direction Dr. The outer curved surface 563b is formed in a shape that overlaps the outer curved surface 563a without any gap when viewed in the radial direction Dr. The outer curved surfaces 563a and 563b may have the same curvature as the inner curved surfaces 553a and 553b of the inner platform member 55A when viewed in the radial direction Dr, or may have a different curvature.

[0056] The outer platform member 56A of the first nozzle module 52A is connected to the entire outer peripheral end 53o of the nozzle body 53 when viewed in the radial direction Dr. The outer first portion 561A is arranged to overlap with the end 53a of the nozzle body 53 on the first side Da1 in the axial direction Da when viewed in the radial direction Dr. The outer second portion 562A is arranged to overlap with the end 53b of the nozzle body 53 on the second side Da2 in the axial direction Da when viewed in the radial direction Dr.

[0057] As shown in FIGS. 4 and 5, the second nozzle module 52B of the plurality of nozzle modules 52 is disposed at the end of the upper half nozzle ring 511 and the lower half nozzle ring 512 on the first side Dc1 in the circumferential direction Dc.

[0058] As shown in FIG. 8, the inner platform member 55B of the second nozzle module 52B integrally has an inner first portion 551B formed on a first side Da1 in the axial direction Da and an inner second portion 552B formed on a second side Da2 in the axial direction Da.

[0059] The inner first portion 551B is formed in the same shape as the inner first portion 551A of the first nozzle module 52A. That is, when viewed from the radial direction Dr, the inner first portion 551B has an inner front surface 551f and a pair of inner first side surfaces 551a and 551b.

[0060] The inner second portion 552B is formed in a shape different from the inner second portion 552A of the first nozzle module 52A. The inner second portion 552B is formed to extend integrally with the inner first portion 551B on the second side Da2 in the axial direction Da. When viewed from the radial direction Dr, the inner second portion 552B has one inner second side surface 552c and one inner third side surface (third side surface) 558c. The inner second portion 552B has only one inner second side surface 552c and one inner third side surface 558c, and does not have an inner rear surface 552r.

[0061] The inner second side surface 552c extends at an incline relative to the inner first side surface 551b when viewed in the radial direction Dr. The inner second side surface 552c extends at an incline from the inner first side surface 551b toward the second side Da2 in the axial direction Da and toward the first side Dc1 in the circumferential direction Dc. The inner second side surface 552c is connected to the inner first side surface 551b. The inner second side surface 552c intersects with the inner inner circumferential surface 55f. The inner second side surface 552c is perpendicular to (intersects with) the inner outer circumferential surface 55g. The inner second side surface 552c is formed parallel to the inner second side surface 552b of the first nozzle module 52A. When viewed in the radial direction Dr, the inner second side surface 552c is formed shorter than the inner second side surface 552b of the first nozzle module 52A.

[0062] The inner third side surface 558c extends and intersects with the inner second side surface 552c when viewed in the radial direction Dr. The inner third side surface 558c is connected to the inner second side surface 552c so as to form an acute angle with it when viewed in the radial direction Dr. That is, in the inner second portion 552B, when viewed in the radial direction Dr, the distance between the inner second side surface 552c and the inner third side surface 558c is formed in a substantially triangular shape, gradually decreasing toward the second side Da2 in the axial direction Da. The inner third side surface 558c is a surface continuous with the inner first side surface 551a and extends in the axial direction Da parallel to the inner first side surface 551a. The inner third side surface 558c intersects with the inner inner circumferential surface 55f. The inner third side surface 558c is perpendicular to (intersects with) the inner outer circumferential surface 55g. The inner third side surface 558c is disposed on a first side Dc1 in the circumferential direction Dc of the inner second portion 552B when viewed in the radial direction Dr. In the second nozzle module 52B, the inner first side surface 551a and the inner third side surface 558c form part of an upper half ring divided surface 511f of the upper half nozzle ring 511 and a lower half ring divided surface 512f of the lower half nozzle ring 512.

[0063] The inner platform member 55B has an inner curved surface 553c on a second side Da2 in the circumferential direction Dc when viewed from the radial direction Dr. The inner curved surface 553c curves smoothly between the inner first side surface 551b and the inner second side surface 552c on the second side Da2 in the circumferential direction Dc of the inner platform member 55B. The inner curved surface 553c is a convex surface that protrudes when viewed from the radial direction Dr. The inner curved surface 553b is formed in a shape that overlaps with the inner curved surface 553a of the first nozzle module 52A without any gap when viewed from the radial direction Dr.

[0064] When viewed in the radial direction Dr, the inner platform member 55B of the second nozzle module 52B is connected to a partial region of the inner circumferential end portion 53i on the inner side Dri in the radial direction Dr of the nozzle body 53. When viewed in the radial direction Dr, the inner first portion 551B is arranged to overlap with the end 53a of the nozzle body 53 on the first side Da1 in the axial direction Da. When viewed in the radial direction Dr, a partial region including the end 53b of the nozzle body 53 is arranged to protrude from the inner second portion 552B to the first side Dc1 in the circumferential direction Dc. In other words, when viewed in the radial direction Dr, the inner second portion 552B overlaps only a partial region of the inner circumferential end portion 53i and does not overlap with the end 53b of the nozzle body 53.

[0065] As shown in FIG. 9, the outer platform member 56B of the second nozzle module 52B integrally has an outer first portion 561B formed on a first side Da1 in the axial direction Da and an outer second portion 562B formed on a second side Da2 in the axial direction Da.

[0066] The outer first portion 561B is formed in the same shape as the outer first portion 561A of the first nozzle module 52A. That is, when viewed from the radial direction Dr, the outer first portion 561B has an outer front surface 561f and a pair of outer first side surfaces 561a and 561b.

[0067] The outer second portion 562B is formed in a shape different from the outer second portion 562A of the first nozzle module 52A. The outer second portion 562B is formed to extend integrally with the outer first portion 561B on the second side Da2 in the axial direction Da. When viewed from the radial direction Dr, the outer second portion 562B has one outer second side surface 562c and one outer third side surface (third side surface) 568c. The outer second portion 562B has only one outer second side surface 562c and one outer third side surface 568c, and does not have an outer rear surface 562r.

[0068] The outer second side surface 562c extends at an incline relative to the outer first side surface 561b when viewed in the radial direction Dr. The outer second side surface 562c extends at an incline from the outer first side surface 561b toward the second side Da2 in the axial direction Da and toward the first side Dc1 in the circumferential direction Dc. The outer second side surface 562c is connected to the outer first side surface 561b. The outer second side surface 562c intersects with the outer inner circumferential surface 56f. The outer second side surface 562c is perpendicular to (intersects with) the outer outer circumferential surface 56g. The outer second side surface 562c is formed parallel to the outer second side surface 562b of the first nozzle module 52A. When viewed in the radial direction Dr, the outer second side surface 562c is formed shorter than the outer second side surface 562b of the first nozzle module 52A.

[0069] The outer third side surface 568c extends and intersects with the outer second side surface 562c when viewed in the radial direction Dr. The outer third side surface 568c is connected to the outer second side surface 562c so as to form an acute angle with it when viewed in the radial direction Dr. That is, in the outer second portion 562B, when viewed in the radial direction Dr, the distance between the outer second side surface 562c and the outer third side surface 568c is formed in a substantially triangular shape, gradually decreasing toward the second side Da2 in the axial direction Da. The outer third side surface 568c is a surface continuous with the outer first side surface 561a and extends in the axial direction Da parallel to the outer first side surface 561a. When viewed in the radial direction Dr, the outer third side surface 568c is disposed on the first side Dc1 in the circumferential direction Dc of the outer second portion 562B. The outer third side surface 568c intersects with the outer inner circumferential surface 56f. The outer third side surface 568c is perpendicular to (intersects with) the outer outer peripheral surface 56g. In the second nozzle module 52B, the outer first side surface 561a and the outer third side surface 568c form part of an upper half ring divided surface 511f of the upper half nozzle ring 511 and a lower half ring divided surface 512f of the lower half nozzle ring 512.

[0070] The outer platform member 56B has an outer curved surface 563c on a second side Da2 in the circumferential direction Dc when viewed from the radial direction Dr. The outer curved surface 563c smoothly curves and connects between the outer first side surface 561b and the outer second side surface 562c on the second side Da2 in the circumferential direction Dc of the outer platform member 56B. The outer curved surface 563c is a convex surface that protrudes when viewed from the radial direction Dr.

[0071] When viewed in the radial direction Dr, the outer platform member 56B of the second nozzle module 52B is connected to a partial region of the outer peripheral end 53o of the nozzle body 53 on the outer side Dro in the radial direction Dr. When viewed in the radial direction Dr, the outer first portion 561B is arranged to overlap with the end 53a of the nozzle body 53 on the first side Da1 in the axial direction Da. When viewed in the radial direction Dr, a partial region including the end 53b of the nozzle body 53 is arranged to protrude from the outer second portion 562B to the first side Dc1 in the circumferential direction Dc. In other words, when viewed in the radial direction Dr, the outer second portion 562B overlaps only a partial region of the outer peripheral end 53o and does not overlap with the end 53b of the nozzle body 53.

[0072] As shown in Figures 4 and 5, among the multiple nozzle modules 52, the third nozzle module 52C is arranged between the second nozzle module 52B, which is arranged at the end of the first side Dc1 in the circumferential direction Dc, and the first nozzle module 52A in the upper half nozzle ring 511 and the lower half nozzle ring 512.

[0073] As shown in FIG. 8, the inner platform member 55C of the third nozzle module 52C integrally has an inner first portion 551C formed on a first side Da1 in the axial direction Da and an inner second portion 552C formed on a second side Da2 in the axial direction Da.

[0074] The inner first portion 551C is formed in the same shape as the inner first portion 551A of the first nozzle module 52A and the inner first portion 551B of the second nozzle module 52B. That is, when viewed from the radial direction Dr, the inner first portion 551C has an inner front surface 551f and a pair of inner first side surfaces 551a and 551b.

[0075] The inner second portion 552C is formed in a shape different from the inner second portion 552A of the first nozzle module 52A and the inner second portion 552B of the second nozzle module 52B. The inner second portion 552C is formed to extend integrally with the inner first portion 551C on the second side Da2 in the axial direction Da. When viewed from the radial direction Dr, the inner second portion 552C has an inner rear surface 552s, a pair of inner second side surfaces 552d and 552b, and an inner third side surface 558d.

[0076] The inner rear surface 552s extends in the circumferential direction Dc when viewed in the radial direction Dr. The inner rear surface 552s is formed to face the second side Da2 in the axial direction Da so as to face away from the inner front surface 551f. When viewed in the radial direction Dr, the inner rear surface 552s is formed to be shorter than the inner rear surface 552r of the first nozzle module 52A. The inner rear surface 552s intersects with the inner inner circumferential surface 55f. The inner rear surface 552s is perpendicular to (intersects with) the inner outer circumferential surface 55g.

[0077] The pair of inner second side surfaces 552d and 552b extend at an incline relative to the pair of inner first side surfaces 551a and 551b when viewed in the radial direction Dr. The pair of inner second side surfaces 552d and 552b are inclined toward the first side surface Dc1 in the circumferential direction Dc as they extend from the pair of inner first side surfaces 551a and 551b toward the second side surface Da2 in the axial direction Da. The inner second side surface 552d is connected to the inner first side surface 551a. The pair of inner second side surfaces 552d and 552b extend parallel to each other when viewed in the radial direction Dr. The distance between the pair of inner second side surfaces 552d and 552b is equal to the distance L2 between the pair of inner second side surfaces 552a and 552b in the first nozzle module 52A. The inner second side surface 552d is formed to have the same length as the inner second side surface 552c of the second nozzle module 52B when viewed in the radial direction Dr. The inner second side surface 552d intersects with the inner inner circumferential surface 55f. The inner second side surface 552d is perpendicular to (intersects with) the inner outer circumferential surface 55g.

[0078] The inner third side surface 558d extends so as to intersect with the inner second side surface 552d when viewed in the radial direction Dr. The inner third side surface 558d is connected to the inner second side surface 552d at an obtuse angle when viewed in the radial direction Dr. The inner third side surface 558d is connected to the inner rear surface 552s at a right angle when viewed in the radial direction Dr. In the third nozzle module 52C, the inner third side surface 558d is not continuous with the inner first side surfaces 551a and 551b, but is continuous with the inner second side surface 552d and the inner rear surface 552r. The inner third side surface 558d extends in the axial direction Da parallel to the inner first side surfaces 551a and 551b. The inner third side surface 558d intersects with the inner inner circumferential surface 55f. The inner third side surface 558d is perpendicular to (intersects with) the inner outer circumferential surface 55g. The inner third side surface 558d is disposed on a first side Dc1 in the circumferential direction Dc of the inner second portion 552C when viewed in the radial direction Dr. The inner third side surface 558d is formed to be continuous with the inner third side surface 558c of the second nozzle module 52B on a second side Da2 in the axial direction Da. In the second nozzle module 52B, the inner third side surface 558d forms part of an upper half ring divided surface 511f of the upper half nozzle ring 511 and a lower half ring divided surface 512f of the lower half nozzle ring 512.

[0079] The inner platform member 55C of the third nozzle module 52C has inner curved surfaces 553a and 553b on a first side Da1 and a second side Da2 in the circumferential direction Dc when viewed in the radial direction Dr.

[0080] The inner platform member 55C of the third nozzle module 52C is connected to the entire inner circumferential end portion 53i of the nozzle body 53 on the inner side Dri in the radial direction Dr, as viewed in the radial direction Dr. The inner first portion 551C is arranged to overlap with the end portion 53a of the nozzle body 53 on the first side Da1 in the axial direction Da, as viewed in the radial direction Dr. The inner second portion 552C is arranged to overlap with the end portion 53b of the nozzle body 53 on the second side Da2 in the axial direction Da, as viewed in the radial direction Dr.

[0081] As shown in FIG. 9, the outer platform member 56C of the third nozzle module 52C integrally has an outer first portion 561C formed on a first side Da1 in the axial direction Da and an outer second portion 562C formed on a second side Da2 in the axial direction Da.

[0082] The outer first portion 561C is formed in the same shape as the outer first portion 561A of the first nozzle module 52A and the outer first portion 561B of the second nozzle module 52B. That is, when viewed from the radial direction Dr, the outer first portion 561C has an outer front surface 561f and a pair of outer first side surfaces 561a and 561b.

[0083] The outer second portion 562C is formed in a shape different from the outer second portion 562A of the first nozzle module 52A and the outer second portion 562B of the second nozzle module 52B. The outer second portion 562C is formed to extend integrally with the outer first portion 561C on the second side Da2 in the axial direction Da. When viewed in the radial direction Dr, the outer second portion 562C has an outer rear surface 562s, a pair of outer second side surfaces 562a and 562b, and an outer third side surface 568d.

[0084] The outer rear surface 562s extends in the circumferential direction Dc when viewed in the radial direction Dr. The outer rear surface 562s is formed to face the second side Da2 in the axial direction Da so as to face away from the outer front surface 561f. When viewed in the radial direction Dr, the outer rear surface 562s is formed to be shorter than the outer rear surface 562r of the first nozzle module 52A. The outer rear surface 562s intersects with the outer inner circumferential surface 56f. The outer rear surface 562s is perpendicular to (intersects with) the outer outer circumferential surface 56g.

[0085] The pair of outer second side surfaces 562d and 562b extend at an incline relative to the pair of outer first side surfaces 561a and 561b when viewed in the radial direction Dr. The pair of outer second side surfaces 562d and 562b are inclined toward the first side surface Dc1 in the circumferential direction Dc as they extend from the pair of outer first side surfaces 561a and 561b toward the second side surface Da2 in the axial direction Da. The outer second side surface 562d is connected to the outer first side surface 561a. The pair of outer second side surfaces 562d and 562b extend parallel to each other when viewed in the radial direction Dr. The distance between the pair of outer second side surfaces 562d and 562b is equal to the distance L2 between the pair of outer second side surfaces 562a and 562b in the first nozzle module 52A. The outer second side surface 562d is formed to have the same length as the outer second side surface 562c of the second nozzle module 52B when viewed in the radial direction Dr. The outer second side surface 562d intersects with the outer inner circumferential surface 56f. The outer second side surface 562d is perpendicular to (intersects with) the outer outer circumferential surface 56g.

[0086] The outer third side surface 568d extends so as to intersect with the outer second side surface 562d when viewed in the radial direction Dr. The outer third side surface 568d is connected to the outer second side surface 562d at an obtuse angle when viewed in the radial direction Dr. The outer third side surface 568d is connected to the outer rear surface 562s at a right angle when viewed in the radial direction Dr. In the third nozzle module 52C, the outer third side surface 568d is not continuous with the inner first side surfaces 551a and 551b, but is continuous with the outer second side surface 562d and the outer rear surface 562s. The outer third side surface 568d extends in the axial direction Da parallel to the outer first side surfaces 561a and 561b. The outer third side surface 568d intersects with the outer inner circumferential surface 56f. The outer third side surface 568d is perpendicular to (intersects with) the outer outer circumferential surface 56g. The outer third side surface 568d is disposed on a first side Dc1 in the circumferential direction Dc of the outer second portion 562C when viewed in the radial direction Dr. The outer third side surface 568d is formed so as to be continuous with the outer third side surface 568c of the second nozzle module 52B on a second side Da2 in the axial direction Da. In the second nozzle module 52B, the outer third side surface 568d forms part of an upper half ring divided surface 511f of the upper half nozzle ring 511 and a lower half ring divided surface 512f of the lower half nozzle ring 512.

[0087] The outer platform member 56C of the third nozzle module 52C has outer curved surfaces 563a and 563b on a first side Da1 and a second side Da2 in the circumferential direction Dc when viewed in the radial direction Dr.

[0088] The outer platform member 56C of the third nozzle module 52C is connected to the entire outer peripheral end 53o of the outer side Dro in the radial direction Dr of the nozzle body 53. The outer first portion 561C is arranged to overlap with the end 53a of the nozzle body 53 on the first side Da1 in the axial direction Da as viewed in the radial direction Dr. The outer second portion 562C is arranged to overlap with the end 53b of the nozzle body 53 on the second side Da2 in the axial direction Da as viewed in the radial direction Dr.

[0089] As shown in FIGS. 4 and 5, the fourth nozzle module 52D of the plurality of nozzle modules 52 is disposed at the end of the upper half nozzle ring 511 and the lower half nozzle ring 512 on the second side Dc2 in the circumferential direction Dc.

[0090] As shown in FIG. 10, the inner platform member 55D of the fourth nozzle module 52D integrally has an inner first portion 551D formed on a first side Da1 in the axial direction Da and an inner second portion 552D formed on a second side Da2 in the axial direction Da.

[0091] The inner first portion 551D is formed to have a size (shape) different from the inner first portion 551A of the first nozzle module 52A, the inner first portion 551B of the second nozzle module 52B, and the inner first portion 551C of the third nozzle module 52C. When viewed from the radial direction Dr, the inner first portion 551D has an inner front surface 551g and a pair of inner first side surfaces 551c and 551d.

[0092] The inner front surface 551g extends in the circumferential direction Dc when viewed in the radial direction Dr. The inner front surface 551g is formed to face the first side Da1 in the axial direction Da. When viewed in the radial direction Dr, the inner front surface 551g is formed to be longer than the inner front surface 551f of the first nozzle module 52A. The inner front surface 551g intersects with the inner inner circumferential surface 55f. The inner front surface 551g is perpendicular to (intersects with) the inner outer circumferential surface 55g.

[0093] The pair of inner first side surfaces 551c and 551d extend in the axial direction Da so as to be perpendicular to the inner front surface 551g when viewed in the radial direction Dr. The pair of inner first side surfaces 551c and 551d extend from both ends of the inner front surface 551g in the circumferential direction Dc toward the second side Da2 in the axial direction Da. The pair of inner first side surfaces 551c and 551d extend parallel to each other when viewed in the radial direction Dr. The pair of inner first side surfaces 551c and 551d are surfaces facing opposite directions in the circumferential direction Dc. The inner first side surfaces 551c and 551d intersect with the inner inner circumferential surface 55f. The inner first side surfaces 551c and 551d are perpendicular to (intersect with) the inner outer circumferential surface 55g. When viewed from the radial direction Dr, the distance L5 between the pair of inner first side surfaces 551c and 551d is different from the distance L1 between the pair of inner first side surfaces 551a and 551b of the first nozzle module 52A. In the present embodiment, the distance L5 is greater than the distance L1.

[0094] Note that the interval L5 is not limited to being larger than the interval L1, and is set appropriately according to the size of the nozzle ring 51 to be formed. Therefore, the interval L5 may be smaller than or the same as the interval L1.

[0095] The inner second portion 552D is formed in a shape different from the inner second portion 552A of the first nozzle module 52A, the inner second portion 552B of the second nozzle module 52B, and the inner second portion 552C of the third nozzle module 52C. The inner second portion 552D is formed to extend integrally with the inner first portion 551D on the second side Da2 in the axial direction Da. When viewed from the radial direction Dr, the inner second portion 552D has one inner second side surface 552d, one inner third side surface 558e, and an inner rear surface 552t. The inner second portion 552D has only one inner second side surface 552d and one inner third side surface 558e.

[0096] The inner rear surface 552t extends in the circumferential direction Dc when viewed in the radial direction Dr. The inner rear surface 552t is formed to face the second side Da2 in the axial direction Da so as to face away from the inner front surface 551g. When viewed in the radial direction Dr, the inner rear surface 552t is formed to be longer than the inner rear surface 552r of the first nozzle module 52A. The inner rear surface 552t intersects with the inner inner circumferential surface 55f. The inner rear surface 552t is perpendicular to (intersects with) the inner outer circumferential surface 55g.

[0097] The inner second side surface 552d extends at an incline relative to the inner first side surface 551c on the first side Dc1 in the circumferential direction Dc. The inner second side surface 552d extends at an incline from the inner first side surface 551c toward the second side Da2 in the axial direction Da, toward the first side Dc1 in the circumferential direction Dc. The inner second side surface 552d is connected to the inner first side surface 551c. The inner second side surface 552d is formed parallel to the inner second side surface 552b of the first nozzle module 52A. The inner second side surface 552d intersects with the inner inner circumferential surface 55f. The inner second side surface 552d is perpendicular to (intersects with) the inner outer circumferential surface 55g.

[0098] The inner third side surface 558e extends so as to intersect with the inner second side surface 552d when viewed in the radial direction Dr. The inner third side surface 558e is connected to the inner rear surface 552t so as to form a right angle when viewed in the radial direction Dr. The inner third side surface 558e is a surface that is continuous with the inner first side surface 551d and extends in the axial direction Da parallel to the inner first side surface 551d. The inner third side surface 558e intersects with the inner inner circumferential surface 55f. The inner third side surface 558e is perpendicular to (intersects with) the inner outer circumferential surface 55g. When viewed in the radial direction Dr, the inner third side surface 558e is disposed on the second side Dc2 of the inner second portion 552D in the circumferential direction Dc. As a result, the inner second portion 552D is formed into a generally trapezoidal shape when viewed in the radial direction Dr, with the distance between the inner second side surface 552d and the inner third side surface 558e gradually increasing toward the second side Da2 in the axial direction Da. In the fourth nozzle module 52D, the inner first side surface 551d and the inner third side surface 558e form an upper half ring divided surface 511g of the upper half nozzle ring 511 and a lower half ring divided surface 512g of the lower half nozzle ring 512.

[0099] The inner platform member 55D has an inner curved surface 553e on a first side Dc1 in the circumferential direction Dc when viewed in the radial direction Dr. The inner curved surface 553e curves smoothly between the inner first side surface 551c and the inner second side surface 552d on the first side Da1 in the circumferential direction Dc of the inner platform member 55D. The inner curved surface 553e is a concave surface when viewed in the radial direction Dr. The inner curved surface 553e is preferably formed in a shape that allows it to make contact with the inner curved surface 553b of the first nozzle module 52A without any gaps.

[0100] The inner platform member 55D of the fourth nozzle module 52D is connected to the entire inner circumferential end portion 53i of the nozzle body 53 on the inner side Dri in the radial direction Dr, as viewed in the radial direction Dr. The inner first portion 551D is arranged to overlap with the end portion 53a of the nozzle body 53 on the first side Da1 in the axial direction Da, as viewed in the radial direction Dr. The inner second portion 552D is arranged to overlap with the end portion 53b of the nozzle body 53 on the second side Da2 in the axial direction Da, as viewed in the radial direction Dr.

[0101] As shown in FIG. 11, the outer platform member 56D of the fourth nozzle module 52D integrally has an outer first portion 561D formed on a first side Da1 in the axial direction Da and an outer second portion 562D formed on a second side Da2 in the axial direction Da.

[0102] The outer first portion 561D is formed to have a size (shape) different from the outer first portion 561A of the first nozzle module 52A, the outer first portion 561B of the second nozzle module 52B, and the outer first portion 561C of the third nozzle module 52C. When viewed from the radial direction Dr, the outer first portion 561D has an outer front surface 561g and a pair of outer first side surfaces 561c and 561d.

[0103] The outer front surface 561g extends in the circumferential direction Dc when viewed in the radial direction Dr. The outer front surface 561g is formed to face the first side Da1 in the axial direction Da. When viewed in the radial direction Dr, the outer front surface 561g is formed to be longer than the outer front surface 561f of the first nozzle module 52A. The outer front surface 561g intersects with the outer inner circumferential surface 56f. The outer front surface 561g is perpendicular to (intersects with) the outer outer circumferential surface 56g.

[0104] The pair of outer first side surfaces 561c and 561d extend in the axial direction Da so as to be perpendicular to the outer front surface 561g when viewed in the radial direction Dr. The pair of outer first side surfaces 561c and 561d extend from both ends of the outer front surface 561g in the circumferential direction Dc toward the second side Da2 in the axial direction Da. The pair of outer first side surfaces 561c and 561d extend parallel to each other when viewed in the radial direction Dr. The pair of outer first side surfaces 561c and 561d are surfaces facing opposite directions in the circumferential direction Dc. The outer first side surfaces 561c and 561d intersect with the outer inner circumferential surface 56f. The outer first side surfaces 561c and 561d are perpendicular to (intersect with) the outer outer peripheral surface 56g. When viewed from the radial direction Dr, the distance L6 between the pair of outer first side surfaces 561c and 561d is different from the distance L3 between the pair of outer first side surfaces 561a and 561b of the first nozzle module 52A. In the present embodiment, the distance L6 is greater than the distance L3.

[0105] Note that the interval L6 is not limited to being larger than the interval L3, and is set appropriately according to the size of the nozzle ring 51 to be formed. Therefore, the interval L6 may be smaller than or the same as the interval L3.

[0106] The outer second portion 562D is formed in a shape different from the outer second portion 562A of the first nozzle module 52A, the outer second portion 562B of the second nozzle module 52B, and the outer second portion 562C of the third nozzle module 52C. The outer second portion 562D is formed to extend integrally with the outer first portion 561D on the second side Da2 in the axial direction Da. When viewed from the radial direction Dr, the outer second portion 562D has one outer second side surface 562d, one outer third side surface 568e, and an outer rear surface 562t. The outer second portion 562D has only one outer second side surface 562d and one outer third side surface 568e.

[0107] The outer rear surface 562t extends in the circumferential direction Dc when viewed in the radial direction Dr. The outer rear surface 562t is formed to face the second side Da2 in the axial direction Da so as to face away from the outer front surface 561g. When viewed in the radial direction Dr, the outer rear surface 562t is formed to be longer than the outer rear surface 562r of the first nozzle module 52A. The outer rear surface 562t intersects with the outer inner circumferential surface 56f. The outer rear surface 562t is perpendicular to (intersects with) the outer outer circumferential surface 56g.

[0108] The outer second side surface 562d extends at an incline relative to the outer first side surface 561c on the first side Dc1 in the circumferential direction Dc. The outer second side surface 562d extends at an incline from the outer first side surface 561c toward the second side Da2 in the axial direction Da, toward the first side Dc1 in the circumferential direction Dc. The outer second side surface 562d is connected to the outer first side surface 561c. The outer second side surface 552d is formed parallel to the outer second side surface 562b of the first nozzle module 52A. The outer second side surface 562d intersects with the outer inner circumferential surface 56f. The outer second side surface 562d is perpendicular to (intersects with) the outer outer circumferential surface 56g.

[0109] The outer third side surface 568e extends so as to intersect with the outer second side surface 562d when viewed in the radial direction Dr. The outer third side surface 568e is connected to the outer rear surface 562t so as to form a right angle when viewed in the radial direction Dr. The outer third side surface 568e is a surface that is continuous with the outer first side surface 561d and extends parallel to the outer first side surface 561d in the axial direction Da. The outer third side surface 568e intersects with the outer inner circumferential surface 56f. The outer second side surface 562d is perpendicular to (intersects with) the outer third side surface 568e. When viewed in the radial direction Dr, the outer third side surface 568e is disposed on the second side Dc2 of the outer second portion 562D in the circumferential direction Dc. As a result, the outer second portion 562D is formed in a generally trapezoidal shape when viewed in the radial direction Dr, with the distance between the outer second side surface 562d and the outer third side surface 568e gradually increasing toward the second side Da2 in the axial direction Da. In the fourth nozzle module 52D, the outer first side surface 561d and the outer third side surface 568e form an upper half ring divided surface 511g of the upper half nozzle ring 511 and a lower half ring divided surface 512g of the lower half nozzle ring 512.

[0110] The outer platform member 56D has an outer curved surface 563e on a first side Dc1 in the circumferential direction Dc when viewed from the radial direction Dr. The outer curved surface 563e curves smoothly between the outer first side surface 561c and the outer second side surface 562d on the first side Da1 in the circumferential direction Dc of the outer platform member 56D. The outer curved surface 563e is a concave surface when viewed from the radial direction Dr. The outer curved surface 563e is preferably formed in a shape that allows it to make contact with the outer curved surface 563b of the first nozzle module 52A without any gaps.

[0111] The outer platform member 56D of the fourth nozzle module 52D is connected to the entire outer peripheral end 53o of the nozzle body 53 on the inner side Dri in the radial direction Dr, as viewed in the radial direction Dr. The outer first portion 561D is arranged to overlap with the end 53a of the nozzle body 53 on the first side Da1 in the axial direction Da, as viewed in the radial direction Dr. The outer second portion 562D is arranged to overlap with the end 53b of the nozzle body 53 on the second side Da2 in the axial direction Da, as viewed in the radial direction Dr.

[0112] (Nozzle diaphragm assembly method) As shown in FIG. 12, an assembly method S10 for a nozzle diaphragm 5 according to an embodiment of the present disclosure includes a step S11 of preparing an inner ring 6, an outer ring 7, and a nozzle module 52, a step S12 of positioning the inner ring 6, a step S13 of positioning the nozzle module 52, a step S14 of positioning the outer ring 7, a step S15 of welding the inner ring 6 to the inner platform member 55, and a step S16 of welding the outer ring 7 to the outer platform member 56.

[0113] In step S11 of preparing the inner ring 6, the outer ring 7, and the nozzle modules 52, the inner ring 6, the outer ring 7, and the plurality of nozzle modules 52 are prepared. For the inner ring 6, an upper-half inner ring member 61 and a lower-half inner ring member 62 constituting the inner ring 6 are manufactured into predetermined shapes. For the outer ring 7, an upper-half outer ring member 71 and a lower-half outer ring member 72 constituting the outer ring 7 are manufactured into predetermined shapes. Furthermore, as the plurality of nozzle modules 52, a plurality of types of nozzle modules 52 with different configurations of the platform member 54 are manufactured. In this embodiment, a plurality of nozzle modules 52 are prepared, including a first nozzle module 52A, a second nozzle module 52B, a third nozzle module 52C, and a fourth nozzle module 52D. The first nozzle module 52A, the second nozzle module 52B, the third nozzle module 52C, and the fourth nozzle module 52D are each manufactured as a single component by cutting a predetermined metal material using a processing machine. Here, a single member does not mean a member made by joining a plurality of parts by welding or the like, but a member formed as a single part without any joining surface by cutting out from a material or the like.

[0114] In step S12 of placing the inner ring 6, as shown in FIG. 13, first, an upper-half inner ring member 61 and a lower-half inner ring member 62 are combined vertically to assemble the annular inner ring 6. Both end portions 61a and 61b of the upper-half inner ring member 61 in the circumferential direction Dc are connected to both end portions 62a and 62b of the lower-half inner ring member 62 in the circumferential direction Dc with connecting members such as bolts. The assembled inner ring 6 is placed in a predetermined location where the nozzle diaphragm 5 will be assembled. The inner ring 6 may be supported by a stand (not shown) or the like, as needed.

[0115] In the process S13 of arranging the nozzle modules 52, as shown in FIG. 14, multiple nozzle modules 52 are arranged on the outer side Dro of the inner ring 6 in the radial direction Dr. Each nozzle module 52 is arranged with the inner platform member 55 aligned along the outer peripheral surface of the inner ring 6. Adjacent nozzle modules 52 in the circumferential direction Dc are arranged so that the inner platform members 55 and the outer platform members 56 are adjacent to each other. A predetermined number of first nozzle modules 52A are arranged side by side in the circumferential direction Dc on the outer sides Dro of the upper-half inner ring member 61 and the lower-half inner ring member 62 in the radial direction Dr. A second nozzle module 52B and a third nozzle module 52C are arranged at the end of the first side Dc1 in the circumferential direction Dc. A fourth nozzle module 52D is arranged at the end of the second side Dc2 in the circumferential direction Dc. As a result, the plurality of nozzle modules 52 are arranged side by side over the entire circumference in the circumferential direction Dc, and an upper half nozzle ring 511 and a lower half nozzle ring 512 are formed.

[0116] In step S13, between the inner platform members 55 adjacent to each other in the circumferential direction Dc, the inner first portions 551A come into contact with each other in the circumferential direction Dc on a first side Da1 in the axial direction Da, such that the inner first portions 551A come into contact with each other in the circumferential direction Dc, the inner first portions 551A and 551C, the inner first portions 551B and 551C, and the inner first portions 551A and 551D. Furthermore, on a second side Da2 in the axial direction Da, the inner second portions 552A come into contact with each other in the circumferential direction Dc, such that the inner second portions 552A come into contact with each other in the circumferential direction Dc, the inner second portions 552A and 552C, the inner second portions 552B and 552C, and the inner second portions 552A and 552D. Similarly, between adjacent outer platform members 56 in the circumferential direction Dc, the outer first portions 561A contact each other in the circumferential direction Dc on a first side Da1 in the axial direction Da, and the outer first portions 561A and 561C, the outer first portion 561B and 561C, and the outer first portion 561A and 561D contact each other in the circumferential direction Dc. Furthermore, on a second side Da2 in the axial direction Da, the outer second portions 562A contact each other in the circumferential direction Dc, and the outer second portions 562A and 562C, the outer second portion 562B and 562C, and the outer second portion 562A and 562D contact each other in the circumferential direction Dc. At this time, the first side surfaces and second side surfaces of the inner platform member 55 and the outer platform member 56, which are side surfaces in the circumferential direction Dc, contact each other. As a result, the inner platform members 55 adjacent to each other in the circumferential direction Dc are arranged in a state where relative positional deviation in the axial direction Da is suppressed.

[0117] In step S14 of arranging the outer ring 7, an upper-half outer ring member 71 and a lower-half outer ring member 72 are combined vertically to assemble the annular outer ring 7, as shown in Fig. 15. Both ends 71a and 71b of the upper-half outer ring member 71 in the circumferential direction Dc are connected to both ends 72a and 72b of the lower-half outer ring member 72 in the circumferential direction Dc with connecting members such as bolts. Thereafter, as shown in Fig. 2, the assembled outer ring 7 is arranged on the outer side Dro in the radial direction Dr of the multiple nozzle modules 52 arranged outward in the radial direction Dr relative to the inner ring 6.

[0118] In step S15 of welding the inner ring 6 and the inner platform member 55, the outer peripheral surface of the inner ring 6 and the inner platform member 55 of each nozzle module 52 are joined by, for example, electron beam welding (EBW). As a result, an inner weld 58 is formed between the inner ring 6 and the inner peripheral surface 55f of the inner platform member 55. Here, step S15 may be performed after step S14 of placing the outer ring 7 is completed, or it may be performed prior to step S14 of placing the outer ring 7, at a stage when multiple nozzle modules 52 have been placed on the outer side Dro of the inner ring 6 in the radial direction Dr. Furthermore, each time one nozzle module 52 is placed on the outer side Dro of the inner ring 6 in the radial direction Dr, each nozzle module 52 may be welded to the inner ring 6 in sequence.

[0119] In process S16 of welding the outer ring 7 and the outer platform member 56, the inner circumferential surface of the outer ring 7 and the outer outer circumferential surface 56g of the outer platform member 56 of each nozzle module 52 are joined by, for example, electron beam welding (EBW). As a result, an outer weld 59 is formed between the outer ring 7 and the outer inner circumferential surface 56f of the outer platform member 56 in each of the nozzle modules 52 arranged side by side in the circumferential direction Dc. In this manner, assembly of the nozzle diaphragm 5 is completed.

[0120] In the above description, the plurality of nozzle modules 52 are arranged on the outer side Dro in the radial direction Dr of the annular inner ring 6, and the annular outer ring 7 is further arranged on the outer side Dro in the radial direction Dr. However, the present invention is not limited to this method. For example, the plurality of nozzle modules 52 may be joined to the outer side Dro in the radial direction Dr of the upper-half inner ring member 61, and then the upper-half outer ring member 71 may be joined to the outer side Dro in the radial direction Dr. Alternatively, the plurality of nozzle modules 52 may be joined to the outer side Dro in the radial direction Dr of the lower-half inner ring member 62, and then the lower-half outer ring member 72 may be joined to the outer side Dro in the radial direction Dr. The annular nozzle diaphragm 5 can then be constructed by connecting the upper-half inner ring member 61 and the lower-half inner ring member 62, and the upper-half outer ring member 71 and the lower-half outer ring member 72.

[0121] (Method of assembling a steam turbine) Next, a description will be given of a method S20 for assembling a steam turbine 1 using the above-described nozzle diaphragm 5. As shown in Fig. 16 , the method S20 for assembling a steam turbine 1 according to the embodiment of the present disclosure includes a step S21 of preparing a casing 2, a step S22 of incorporating the nozzle diaphragm 5, and a step S23 of closing the casing 2.

[0122] In step S21 of preparing the casing 2, the upper half casing 21 and the lower half casing 22 that constitute the casing 2 are manufactured into a predetermined shape. As shown in Fig. 17, the lower half casing 22 is placed via support legs (not shown) at the installation location of the steam turbine 1. When assembling the steam turbine 1 during maintenance of an already installed steam turbine 1, it is not necessary to newly install the lower half casing 22. Furthermore, the upper half casing 21 is not placed on the lower half casing 22, and the lower half casing 22 is open toward the upper Dvu in the vertical direction Dv.

[0123] 18, in step S22 of assembling the nozzle diaphragm 5, the rotor 3 and the nozzle diaphragm 5 are assembled into the casing 2. In the embodiment of the present disclosure, the nozzle diaphragm 5 is an annular shaped diaphragm that has been assembled in advance by the nozzle diaphragm 5 assembling method S10, and is then assembled into the casing 2. Here, the specific procedure for assembling the rotor 3 and the nozzle diaphragm 5 is not limited in any way.

[0124] In step S23 of closing the casing 2, the casing 2 incorporating the rotor 3 and the nozzle diaphragm 5 is closed. In the embodiment of the present disclosure, the upper half casing 21 is placed on the lower half casing 22, and the lower half casing 22 and the upper half casing 21 are fixed together with fastening members such as bolts (not shown) in a state where the upper half casing divided surface and the lower half casing divided surface are in contact with each other. This closes the casing 2, completing the assembly of the steam turbine 1 as shown in FIG. 1.

[0125] (Method of disassembling a steam turbine) Next, a description will be given of a method S30 for disassembling a steam turbine 1 using the above-described nozzle diaphragm 5. As shown in Fig. 19 , the method S30 for disassembling a steam turbine 1 according to the embodiment of the present disclosure includes a step S31 of opening a part of the casing 2 and a step S32 of removing the nozzle diaphragm 5.

[0126] In step S31 of opening a portion of the casing 2, the casing 2 is opened in order to remove the nozzle diaphragm 5. To do this, the fastening members are removed at the contact points between the upper half casing divided surface and the lower half casing divided surface, and the connection between the lower half casing 22 and the upper half casing 21 is released. Then, the upper half casing 21 is removed. As a result, the lower half casing 22 opens upward Dvu in the vertical direction Dv, as shown in FIG. 18 .

[0127] In step S32 of removing the nozzle diaphragm 5, the rotor 3 and the nozzle diaphragm 5 are removed from the casing 2. In the embodiment of the present disclosure, the rotor 3 and the nozzle diaphragm 5 are removed upward from the lower half casing 22. Here, the specific procedure for removing the rotor 3 and the nozzle diaphragm 5 is not limited in any way. As a result, as shown in FIG. 19 , only the lower half casing 22 remains open toward the upward direction Dvu in the vertical direction Dv.

[0128] In this way, disassembly of the steam turbine 1 is completed. Thereafter, maintenance is performed on the casing 2, the rotor 3, and the nozzle diaphragm 5 as necessary. The nozzle diaphragm 5 may be replaced with a new nozzle diaphragm 5 after use. In this case, after disassembly of the steam turbine 1, the new nozzle diaphragm 5 is assembled into the steam turbine 1 by the method S20 for assembling the steam turbine 1.

[0129] (Action and effect) A plurality of nozzle modules 52 as described above are arranged in the circumferential direction Dc between the inner ring 6 and the outer ring 7 to form a nozzle ring 51. The platform member 54 of each nozzle module 52 has a first portion, an inner first portion 551 and an outer first portion 561, and a second portion, an inner second portion 552 and an outer second portion 562. The inner first portion 551 has a pair of inner first side surfaces 551a, 551b, 551c, and 551d extending in the axial direction Da. In contrast, the inner second portion 552 has inner second side surfaces 552a, 552b, 552c, and 552d. Similarly, the outer first portion 561 has a pair of outer first side surfaces 561a, 561b, 561c, and 561d extending in the axial direction Da. In contrast, the outer second portion 562 has outer second side surfaces 562a, 562b, 562c, and 562d. As a result, when viewed from the radial direction Dr, the inner second portion 552 and the outer second portion 562 extend at an incline so as to bend relative to the inner first portion 551 and the outer first portion 561. By combining such inner first portions 551 with each other and inner second portions 552 with each other, or outer first portions 561 with each other and outer second portions 562 with each other, relative positional deviation in the axial direction Da between the nozzle modules 52 can be suppressed. As a result, positional deviation can be suppressed and multiple nozzle modules 52 can be reliably assembled with high precision. Furthermore, the inner first side surfaces 551a, 551b, 551c, and 551d and the outer first side surfaces 561a, 561b, 561c, and 561d extend parallel to the central axis O. Therefore, when arranging multiple nozzle modules 52, a highly accurate nozzle ring 51 can be easily formed simply by arranging the inner first portion 551 and the outer first portion 561. As a result, the nozzle module 52 that allows the nozzle ring 51 to be manufactured with high precision can be easily and reliably obtained.

[0130] Furthermore, in the first nozzle module 52A, the third nozzle module 52C, and the fourth nozzle module 52D, the inner first portion 551 and the outer first portion 561 are arranged to overlap the end portion 53a of the nozzle body 53 on the first side Da1 in the axial direction Da, as viewed in the radial direction Dr. Furthermore, the inner second portion 552 and the outer second portion 562 are arranged to overlap the end portion 53b of the nozzle body 53 on the second side Da2 in the axial direction Da, as viewed in the radial direction Dr. This allows the platform member 54 to be formed in a shape corresponding to the shape of the nozzle body 53, which has a blade-like shape. As a result, the platform member 54, which has the first portion and the second portion, can be formed in a minimum size while stably supporting the nozzle body 53.

[0131] Furthermore, in the first nozzle module 52A, the distance L1 between the pair of inner first side surfaces 551a and 551b in the inner first portion 551A is the same as the distance L2 between the pair of inner second side surfaces 552a and 552b in the inner second portion 552A. As a result, there is no need to complexly design the shapes of the second portions 552 and 562 relative to the first portions 551 and 561. This allows the nozzle module 52 to be easily designed and manufactured.

[0132] Furthermore, when viewed from the radial direction Dr, each platform member 54 has inner curved surfaces 553a, 553b, 553c, and 553e and outer curved surfaces 563a, 563b, 563c, and 563e on at least one of the first side Da1 and the second side Da2 in the circumferential direction Dc. This allows smooth connections between the inner first side surfaces 551a, 551b, 551c, and 551d and the inner second side surfaces 552a, 552b, 552c, and 552d, and between the outer first side surfaces 561a, 561b, 561c, and 561d and the outer second side surfaces 562a, 562b, 562c, and 562d. Therefore, when manufacturing each platform member 54, the first side surfaces and the second side surfaces can be easily processed into a continuous surface.

[0133] Furthermore, in the second nozzle module 52B, the third nozzle module 52C, and the fourth nozzle module 52D, the second portions 552 and 562 have inner third side surfaces 558c, 558d, and 558e extending in the axial direction Da and outer third side surfaces 568c, 568d, and 568e. As a result, in the second portions 552 and 562, surfaces parallel to the inner first side surfaces 551a, 551b, 551c, and 551d and the outer first side surfaces 561a, 561b, 561c, and 561d are formed. As a result, in a configuration in which the nozzle ring 51 is divided into two in the vertical direction Dv, including an upper half nozzle ring 511 and a lower half nozzle ring 512, the dividing surface between the upper half nozzle ring 511 and the lower half nozzle ring 512 can also be formed in the second portions 552 and 562. In particular, in this embodiment, the inner first side surface 551a, the inner third side surface 558c, and the inner third side surface 558d, the outer first side surface 561a, the outer third side surface 568c, and the outer third side surface 568d, the inner first side surface 551d and the inner third side surface 558e, and the outer first side surface 561d and the outer third side surface 568e extend continuously in a straight line when viewed in the radial direction Dr. This makes it possible to easily form the dividing surface between the upper half nozzle ring 511 and the lower half nozzle ring 512 in a straight line extending in the axial direction Da.

[0134] Furthermore, the platform member 54 of each nozzle module 52 has an inner outer peripheral surface 55g and an outer outer peripheral surface 56g that extend in the circumferential direction Dc on the side opposite the inner inner peripheral surface 55f and outer inner inner peripheral surface 56f connected to the nozzle body 53 and are parallel to the central axis O when viewed from the circumferential direction Dc. Therefore, the inner outer peripheral surface 55g and the outer outer peripheral surface 56g, which are outermost in the radial direction Dr, of the platform member 54, extend straight in the axial direction Da. As a result, the boundary between the outer peripheral surface of the inner ring 6 and the inner outer peripheral surface 55g, which faces the inner outer peripheral surface 55g in the radial direction Dr, and the boundary between the inner peripheral surface of the outer ring 7 and the outer outer peripheral surface 56g, which faces the outer outer peripheral surface 56g in the radial direction Dr, have simple shapes that are straight lines extending parallel to the central axis O when viewed from the circumferential direction Dc. This facilitates the welding operation when forming the inner weld 58 and the outer weld 59. Therefore, the efficiency of welding work can be improved when joining the platform member 54 to the inner ring 6 and the outer ring 7 by welding.

[0135] Furthermore, the platform members 54 of each nozzle module 52 include an inner platform member 55 and an outer platform member 56. Therefore, the inner platform member 55 and the outer platform member 56 can be firmly connected to each other on both sides in the radial direction Dr, sandwiching the nozzle body 53 therebetween. This makes it possible to more effectively suppress relative positional deviation in the axial direction Da.

[0136] Furthermore, the inner first portions 551A, 551B, 551C, and 551D have different intervals L1 and L3 than the outer first portions 561A, 561B, 561C, and 561D, and are therefore different in size. Similarly, the inner second portions 552A, 552B, 552C, and 552D have different intervals L2 and L3 than the outer second portions 562A, 562B, 562C, and 562D, and are therefore different in size. Therefore, the shape of the platform member 54 is changed on both sides of the nozzle body 53 in the radial direction Dr. This allows the nozzle module 52 to be formed appropriately to match the shape and size of the inner ring 6 and the outer ring 7.

[0137] Furthermore, in the nozzle diaphragm 5 and the method S10 for assembling the nozzle diaphragm 5, a plurality of nozzle modules 52 as described above are arranged side by side between the inner ring 6 and the outer ring 7 to form the nozzle ring 51. As a result, the nozzle diaphragm 5 equipped with a highly accurate nozzle ring 51 can be manufactured easily and reliably.

[0138] Furthermore, the nozzle diaphragm 5 has the inner ring 6 and the platform member 54 joined at an inner weld 58, and the outer ring 7 and the platform member 54 joined at an outer weld 59. As a result, it is possible to manufacture a robust nozzle diaphragm 5 equipped with a highly accurate nozzle ring 51.

[0139] Furthermore, the nozzle diaphragm 5 includes a plurality of first nozzle modules 52A of the same shape. By including a plurality of first nozzle modules 52A of the same shape, it is possible to reduce the number of types of parts that make up the nozzle ring 51. Therefore, the nozzle modules 52 that make up the nozzle ring 51 can be manufactured efficiently.

[0140] In the steam turbine 1 and the method for assembling the steam turbine 1 S20 described above, the steam turbine 1 can be manufactured with improved work efficiency during assembly by using a highly accurate nozzle diaphragm 5 constructed using the nozzle module 52 described above.

[0141] In the method S30 for disassembling the steam turbine 1 as described above, the nozzle module 52 as described above is used, so that the steam turbine 1 can be easily disassembled.

[0142] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0143] In the above embodiment, the casing 2 is configured to be divided into two halves, the upper half casing 21 and the lower half casing 22, and the rotor 3 and nozzle diaphragm 5 are installed or removed with the upper half casing 21 removed, but this is not limited to this. For example, the casing 2 may be configured to be cylindrical and extend in the axial direction Da, and the rotor 3 and nozzle diaphragm 5 may be installed or removed by moving them in the axial direction Da relative to the casing 2.

[0144] In the above embodiment, the procedure has been described as the method S10 for assembling the nozzle diaphragm 5, the method S20 for assembling the steam turbine 1, and the method S30 for disassembling the steam turbine 1, but the order can be changed as appropriate.

[0145] The nozzle module 52, nozzle diaphragm 5, steam turbine 1, nozzle diaphragm 5 assembling method S10, steam turbine 1 assembling method S20, and steam turbine 1 disassembling method S30 described in the embodiment can be understood, for example, as follows.

[0146] (1) A nozzle module 52 according to a first aspect is a nozzle module 52 constituting a nozzle ring 51 that can be arranged between an inner ring 6 extending in a circumferential direction Dc about a central axis O and an outer ring 7 that is arranged on an outer side Dro in a radial direction Dr centered on the central axis O relative to the inner ring 6 and extends in the circumferential direction Dc, the nozzle module 52 including: a nozzle body 53 having a wing-shaped cross section extending in the radial direction Dr; and platform members 54 integrally connected to end portions of the nozzle body 53 in the radial direction Dr, wherein the platform members 54 are formed on a first side Da1 in an axial direction Da in which the central axis O extends, when viewed from the radial direction Dr, and have a pair of first side surfaces 551 a, 551 b extending in the axial direction Da. , 551c, and 551d, and a second side Da2 in the axial direction Da with respect to the first portions 551, 551A, 551B, 551C, 551D, 561, 561A, 561B, 561C, and 561D when viewed from the radial direction Dr. and second portions 552, 552A, 552B, 552C, 552D, 562, 562A, 562B, 562C, 562D having second side surfaces 552a, 552b, 552c, 552d, 562a, 562b, 562c, 562d extending at an angle relative to the first side surfaces 551a, 551b, 551c, 551d.

[0147] As a result, when viewed from the radial direction Dr, the second portions 552 and 562 extend at an angle so as to bend relative to the first portions 551 and 561. By combining such first portions 551 and second portions 552, relative positional deviation in the axial direction Da between the nozzle modules 52 can be suppressed. As a result, positional deviation can be suppressed and multiple nozzle modules 52 can be reliably assembled with high precision. Furthermore, the first side surfaces 551a, 551b, 551c, 551d, 561a, 561b, 561c, and 561d extend parallel to the central axis O. Therefore, when arranging multiple nozzle modules 52, a highly accurate nozzle ring 51 can be easily formed simply by arranging the first portions 551 and 561. These features make it possible to obtain nozzle modules 52 that enable the easy and reliable manufacture of highly accurate nozzle rings 51.

[0148] (2) The nozzle module 52 of the second aspect is the nozzle module 52 of (1), wherein the first portions 551, 551A, 551B, 551C, 551D, 561, 561A, 561B, 561C, and 561D are arranged to overlap with the end portion 53a of the nozzle body 53 on the first side Da1 of the axial direction Da when viewed from the radial direction Dr, and the second portions 552, 552A, 552C, 552D, 562, 562A, 562C, and 562D are arranged to overlap with the end portion 53b of the nozzle body 53 on the second side Da2 of the axial direction Da when viewed from the radial direction Dr.

[0149] This allows the platform member 54 to be formed in a shape that corresponds to the shape of the airfoil-shaped nozzle body 53. As a result, the platform member 54, which has the first and second portions, can be formed in a minimum size while stably supporting the nozzle body 53.

[0150] (3) The nozzle module 52 according to the third aspect is the nozzle module 52 of (1) or (2), wherein the second portions 552, 552A, 552C, 562, 562A, 562C have a pair of second side surfaces 552a, 552b, 562a, 562b when viewed from the radial direction Dr, and the spacing L1 between the pair of first side surfaces 551a, 551b, 551c, 551d is equal to the spacing L2 between the pair of second side surfaces 552a, 552b, 562a, 562b when viewed from the radial direction Dr.

[0151] This eliminates the need to design complex shapes for the second portions 552 and 562 relative to the first portions 551 and 561. This allows the nozzle module 52 to be easily designed and manufactured.

[0152] (4) The nozzle module 52 according to the fourth aspect is any one of the nozzle modules 52 of (1) to (3), wherein the platform member 54 has, when viewed from the radial direction Dr, curved surfaces 553a, 553b, 553c, 553e, 563a, 563b, 563c, 563e on at least one of the first side Da1 and the second side Da2 in the circumferential direction Dc that curve and connect between the first side surfaces 551a, 551b, 551c, 551d, 561a, 561b, 561c, and 561d and the second side surfaces 552a, 552b, 552c, 552d, 562a, 562b, 562c, and 562d.

[0153] This allows smooth connection between the first side surfaces 551a, 551b, 551c, 551d, 561a, 561b, 561c, and 561d and the second side surfaces 552a, 552b, 552c, 552d, 562a, 562b, 562c, and 562d. Therefore, when manufacturing each platform member 54, the first side surface and the second side surface can be easily processed into a continuous surface.

[0154] (5) The nozzle module 52 relating to the fifth aspect is any one of the nozzle modules 52 of (1) to (4), and the second portions 552, 552B, 552C, 552D, 562, 562B, 562C, 562D have third side surfaces 558c, 558d, 558e, 568c, 568d, 568e extending in the axial direction Da parallel to the first side surfaces 551a, 551b, 551c, 551d, 561a, 561b, 561c, 561d.

[0155] As a result, a surface parallel to the first side surfaces 551a, 551b, 551c, 551d, 561a, 561b, 561c, and 561d is formed in the second portions 552 and 562. As a result, when the nozzle ring 51 is configured to include an upper half nozzle ring 511 and a lower half nozzle ring 512 that are divided in half in the vertical direction Dv, the dividing surface between the upper half nozzle ring 511 and the lower half nozzle ring 512 can also be formed in the second portions 552 and 562.

[0156] (6) A nozzle module 52 according to a sixth aspect is any one of the nozzle modules 52 of (1) to (5), wherein the platform member 54 has inner circumferential surfaces 55f, 56f connected to the nozzle main body 53, and outer circumferential surfaces 55g, 56g that face the opposite side of the inner circumferential surfaces 55f, 56f in the radial direction Dr, extend in the circumferential direction Dc so as to intersect with the first side surfaces 551a, 551b, 551c, 551d, 561a, 561b, 561c, 561d and the second side surfaces 552a, 552b, 552c, 552d, 562a, 562b, 562c, 562d, and are parallel to the central axis when viewed from the circumferential direction Dc.

[0157] As a result, the outer peripheral surfaces 55g and 56g, which are the outermost of the platform member 54 in the radial direction Dr, extend straight in the axial direction Da. Therefore, the boundaries between the outer peripheral surfaces 55g and 56g and the inner ring 6 and the outer ring 7 that face each other in the radial direction Dr have a simple shape, such as a straight line extending parallel to the center axis O when viewed from the circumferential direction Dc. This makes welding easier. Therefore, it is possible to improve the efficiency of welding when joining the platform member 54 to the inner ring 6 and the outer ring 7 by welding.

[0158] (7) A nozzle module 52 according to a seventh aspect is the nozzle module 52 of any one of (1) to (6), wherein the platform member 54 includes an inner platform member 55 integrally connected to an inner peripheral end 55i of an inner side Dri in the radial direction Dr of the nozzle body 53, and an outer platform member 56 integrally connected to an outer peripheral end 55o of an outer side Dro in the radial direction Dr of the nozzle body 53, and the inner platform member 55 includes inner first portions 551, 551A, 551B, 551C, and 551D as the first portion, and inner second portions 552, 552E as the second portion. The outer platform member 56 has outer first portions 561, 561A, 561B, 561C, 561D as the first portion and outer second portions 562, 562A, 562B, 562C, 562D as the second portion, and the inner first portions 551, 551A, 551B, 551C, 551D and the outer first portions 561, 561A, 561B, 561C, 561D, and the inner second portions 552, 552A, 552B, 552C, 552D and the outer second portions 562, 562A, 562B, 562C, 562D are formed in different shapes, respectively.

[0159] This allows the inner platform member 55 and the outer platform member 56 to be firmly connected on both sides of the nozzle body 53 in the radial direction Dr. This makes it possible to more effectively prevent relative positional deviation in the axial direction Da. Furthermore, the shapes of the platform members 54 are different on both sides of the nozzle body 53 in the radial direction Dr. This allows the nozzle module 52 to be formed appropriately to match the shapes and sizes of the inner ring 6 and the outer ring 7.

[0160] (8) The nozzle diaphragm 5 according to the eighth aspect comprises any one of the nozzle modules 52 of (1) to (7), an inner ring 6 arranged on the inner side Dri of the nozzle module 52 in the radial direction Dr and extending in the circumferential direction Dc, and an outer ring 7 arranged on the outer side Dro of the nozzle module 52 in the radial direction Dr and extending in the circumferential direction Dc, and a plurality of the nozzle modules 52 are arranged side by side between the inner ring 6 and the outer ring 7 to form a nozzle ring 51.

[0161] This makes it possible to easily and reliably manufacture the nozzle diaphragm 5 equipped with the nozzle ring 51 with high precision.

[0162] (9) The nozzle diaphragm 5 according to the ninth aspect is the nozzle diaphragm 5 of (8), further comprising an inner weld 58 formed between the inner ring 6 and the plurality of platform members 54, joining the inner ring 6 and the platform members 54, and an outer weld 59 formed between the outer ring 7 and the plurality of platform members 54, joining the outer ring 7 and the platform members 54.

[0163] This makes it possible to manufacture a robust nozzle diaphragm 5 equipped with a highly accurate nozzle ring 51.

[0164] (10) The nozzle diaphragm 5 according to a tenth aspect is the nozzle diaphragm 5 of (8) or (9), and includes a plurality of the nozzle modules 52 of the same shape.

[0165] In this way, by providing a plurality of nozzle modules 52A of the same shape, it is possible to reduce the number of types of parts that make up the nozzle ring 51. Therefore, the nozzle modules 52 that make up the nozzle ring 51 can be manufactured efficiently.

[0166] (11) A steam turbine 1 according to an eleventh aspect comprises a nozzle diaphragm 5 selected from any one of (8) to (10), a cylindrical casing 2 arranged on the outer side Dro of the nozzle diaphragm 5 in the radial direction Dr and extending in the axial direction Da, and a rotor 3 arranged rotatably around the central axis O relative to the nozzle diaphragm 5 and the casing 2 and housed in the casing 2.

[0167] This allows the steam turbine 1 to be manufactured with improved work efficiency during assembly.

[0168] (12) A method S10 for assembling a nozzle diaphragm 5 according to a twelfth aspect is a method S10 for assembling a nozzle diaphragm 5 according to any one of (8) to (10), and includes a step S11 of preparing the inner ring 6, the outer ring 7, and a plurality of the nozzle modules 52, a step S12 of arranging the inner ring 6, a step S13 of arranging the nozzle module 52 on the outer side Dro in the radial direction Dr relative to the inner ring 6, a step S14 of arranging the outer ring 7 on the outer side Dro in the radial direction Dr relative to the plurality of the nozzle modules 52, a step S15 of welding the inner ring 6 and the platform member 55 together, and a step S16 of welding the outer ring 7 and the platform member 56 together.

[0169] This makes it possible to easily and reliably manufacture the nozzle diaphragm 5 equipped with the nozzle ring 51 with high precision.

[0170] (13) A method S20 for assembling a steam turbine 1 according to a thirteenth aspect includes a step S21 of preparing a casing 2 and a step S22 of incorporating any one of nozzle diaphragms 5 (8) to (10) into the casing 2.

[0171] This allows the steam turbine 1 to be manufactured with improved work efficiency during assembly.

[0172] (14) A disassembly method S30 for a steam turbine 1 according to a fourteenth aspect includes a step S31 of opening a portion of a casing 2, and a step S32 of removing any one of nozzle diaphragms 5 (8) to (10) from the casing 2.

[0173] This allows the steam turbine 1 to be easily disassembled. [Explanation of symbols]

[0174] 1. Steam turbine 2...Casing 3...Rotor 5...Nozzle diaphragm 6...Inner circle 7...Outer ring 21...Upper casing 22...Lower casing 27...Steam inlet 28...Steam outlet 31...Rotation axis 31a, 31b...ends 32... Moving blade 33A…First bearing 33B…Second bearing 51...Nozzle ring 52...Nozzle module 52A...First nozzle module 52B...Second nozzle module 52C...Third nozzle module 52D...Fourth nozzle module 53...Nozzle body 53a, 53b...ends 53i...Inner edge 53o...Outer edge 54...Platform member 54f…Inner peripheral surface 54g…Outer surface 55, 55A, 55B, 55C, 55D...Inner platform members 55f…inner circumferential surface 55g…inner and outer circumferential surfaces 56, 56A, 56B, 56C, 56D...outside プラットフォーム material 56f…outer inner circumferential surface 56g…outer peripheral surface 58…inside welding part 59...Outside welding part 61… Upper inner wheel component 61a, 61b... Ends 62… Lower inner wheel component 62a, 62b... Ends 71…Upper half outer wheel parts 71a, 71b... Ends 72…Lower half outer wheel parts 72a, 72b... Ends 511…upper halfノズルリング 511f, 511g…upper half リング split surface 512…The second half of ノズルリング 512f, 512g…lower half リング split surface 551, 551A, 551B, 551C, 551D… Inner First Part (Part 1) 551a, 551b, 551c, 551d… Inner first lateral surface (first lateral surface) 551f, 551g... inner front (front) 552, 552A, 552B, 552C, 552D… Inner Second Part (Second Part) 552a, 552b, 552c, 552d… inner second lateral surface (second lateral surface) 552r, 552s, 552t… inside rear (rear) 553a, 553b, 553c, 553e… Inner curved surfaces (curved surfaces) 558c, 558d, 558e… inner third side (third side) 561, 561A, 561B, 561C, 561D…Outer first part (first part) 561a, 561b, 561c, 561d… outer first lateral surface (first lateral surface) 561f, 561g… outer front (front) 562, 562A, 562B, 562C, 562D… Outer second part (second part) 562a, 562b, 562c, 562d...Outer second side (second side) 562r, 562s, 562t...Outer rear surface (rear surface) 563a, 563b, 563c, 563e...Outer curved surface (curved surface) 568c, 568d, 568e...Outer third side (third side) Da...Axial direction Da1…First side (axial direction) Da2…Second side (axial direction) Dc…Circumferential direction Dc1…First side (circumferential direction) Dc2…Second side (circumferential direction) Dr…Radial direction Dri…inside Dro...outside Dv: vertical direction Dvu…upper DVD…Downward L1, L2, L3, L4, L5, L6...interval O…Central axis S10...Nozzle diaphragm assembly method S11: A step of preparing an inner ring, an outer ring, and a nozzle module S12: Placement of the inner ring S13: Step of arranging the nozzle module S14: The outer ring is placed S15: A process of welding the inner ring and the inner platform member S16: A process of welding the outer ring and the outer platform member S20...Steam turbine assembly method S21: Casing preparation process S22: Process of assembling the nozzle diaphragm S23: Closing the casing S30...Steam turbine disassembly method S31: Opening part of the casing S32: Removing the nozzle diaphragm

Claims

1. A nozzle ring that can be disposed between an inner ring that extends in a circumferential direction about a central axis and an outer ring that is disposed radially outward of the inner ring about the central axis and extends in the circumferential direction, an upper half nozzle ring disposed vertically above the central axis and formed in a semicircular ring shape centered on the central axis; and a lower half nozzle ring disposed vertically below the central axis and formed in a semicircular ring shape centered on the central axis, the upper half nozzle ring and the lower half nozzle ring each have a plurality of nozzle modules arranged side by side in the circumferential direction, The nozzle module includes: a nozzle body having a wing-shaped cross section extending in the radial direction; and platform members each integrally connected to an end of the nozzle body in the radial direction, The platform member is a first portion formed on a first side in an axial direction in which the central axis extends when viewed from the radial direction and having a pair of first side surfaces extending in the axial direction; a second portion formed to extend toward a second side in the axial direction relative to the first portion when viewed from the radial direction, and having a second side surface extending at an angle relative to the first side surface, the upper half nozzle ring and the lower half nozzle ring each include a first nozzle module, a second nozzle module, a third nozzle module, and a fourth nozzle module as the plurality of nozzle modules; the first nozzle module, the second nozzle module, the third nozzle module, and the fourth nozzle module each have a different platform member configuration; the second nozzle module and the third nozzle module are arranged at first circumferential side ends of the upper half nozzle ring and the lower half nozzle ring, the fourth nozzle module is disposed at an end portion of the upper half nozzle ring and the lower half nozzle ring on a second side in the circumferential direction, In the upper half nozzle ring and the lower half nozzle ring, a plurality of the first nozzle modules are arranged between the second nozzle module and the third nozzle module and the fourth nozzle module in the circumferential direction, the upper half nozzle ring has two upper half ring dividing surfaces which are horizontal surfaces facing downward in the vertical direction, the lower half nozzle ring has two lower half ring dividing surfaces which are horizontal surfaces facing upward in the vertical direction, a nozzle ring in which one of the upper half-ring divided surface and the lower half-ring divided surface is formed by the second nozzle module and the third nozzle module, and the other is formed by the fourth nozzle module;

2. the first portion is disposed so as to overlap an end of the nozzle body on a first side in the axial direction when viewed from the radial direction, The nozzle ring according to claim 1 , wherein the second portion is arranged to overlap an end of the nozzle body on the second side in the axial direction when viewed from the radial direction.

3. The second portion has a pair of second side surfaces when viewed in the radial direction, The nozzle ring according to claim 1 or 2, wherein, when viewed from the radial direction, the distance between the pair of first side surfaces is equal to the distance between the pair of second side surfaces.

4. 4. The nozzle ring according to claim 1, wherein the platform member has a curved surface on at least one of a first side and a second side in the circumferential direction, the curved surface connecting the first side surface and the second side surface in a curved manner, when viewed from the radial direction.

5. The nozzle ring according to claim 1 , wherein the second portion has a third side surface that extends in the axial direction parallel to the first side surface when viewed in the radial direction.

6. The platform member is an inner circumferential surface connected to the nozzle body; 6. The nozzle ring according to claim 1, further comprising an outer circumferential surface that faces a side opposite to the inner circumferential surface in the radial direction, extends in the circumferential direction so as to intersect with the first side surface and the second side surface, and is parallel to the central axis when viewed in the circumferential direction.

7. The platform member is an inner platform member integrally connected to the radially inner inner circumferential end of the nozzle body; an outer platform member integrally connected to the radially outer peripheral end of the nozzle body, the inner platform member has an inner first portion as the first portion and an inner second portion as the second portion; the outer platform member has an outer first portion as the first portion and an outer second portion as the second portion; The nozzle ring according to claim 1 , wherein the first inner portion and the first outer portion, and the second inner portion and the second outer portion are formed in different shapes.

8. A nozzle ring according to any one of claims 1 to 7; an inner ring disposed radially inward relative to the nozzle module and extending in the circumferential direction; an outer ring disposed radially outward of the nozzle module and extending in the circumferential direction; The nozzle modules are nozzle diaphragms arranged side by side between the inner ring and the outer ring to form the nozzle ring.

9. an inner weld formed between the inner ring and a plurality of the platform members, joining the inner ring and the platform members; The nozzle diaphragm of claim 8 , further comprising: outer welds formed between said outer ring and a plurality of said platform members, said outer ring and said platform members joining said outer ring and said platform members.

10. The nozzle diaphragm according to claim 8 or 9, comprising a plurality of the nozzle modules having the same shape.

11. A nozzle diaphragm according to any one of claims 8 to 10; a cylindrical casing disposed radially outward of the nozzle diaphragm and extending in the axial direction; a rotor disposed rotatably about the central axis relative to the nozzle diaphragm and the casing and housed in the casing.

12. A method for assembling the nozzle diaphragm according to any one of claims 8 to 10, comprising the steps of: providing the inner ring, the outer ring, and a plurality of the nozzle modules; disposing the inner ring; disposing the nozzle module radially outwardly of the inner ring; disposing the outer ring radially outward of the plurality of nozzle modules; welding the inner ring and the platform member together; and welding the outer ring and the platform member together.

13. providing a casing; and a step of incorporating the nozzle diaphragm according to any one of claims 8 to 10 into the casing.

14. opening a portion of the casing; A method for disassembling a steam turbine, comprising: removing the nozzle diaphragm according to any one of claims 8 to 10 from the casing.

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