Primary vane segment and unit, stationary vane unit, and steam turbine

Abstract

A primary vane segment has: an outer ring extending in a circumferential direction; and a plurality of primary vanes arranged and installed in the circumferential direction on a radially inner side of the outer ring. The primary vanes have: a vane body extending in the radial direction; and an outer shroud formed on a radially outer side of the vane body with respect to the axis. The outer shroud has: a shroud main body; and a buried portion connected to the radially outer side of the shroud main body. The buried portion has: a buried front end surface facing an upstream side of the axis; and a buried rear end surface facing a downstream side of the axis. The outer ring has an outer ring groove into which the outer shroud of each of the plurality of primary vanes enters. The buried front end surface is located at a position more on the upstream side of the axis than a leading edge of the vane body. The buried rear end surface is located at a position more on the upstream side of the axis than a trailing edge of the vane body.

Description

Technical Field

[0001] The present invention relates to a primary stationary blade segment having multiple primary stationary blades, a primary stationary blade segment unit having the primary stationary blade segment, a stationary unit having the primary stationary blade segment, and a steam turbine having the primary stationary blade segment.

[0002] This application claims priority under Japanese Patent Application No. 2021-104776, filed in Japan on June 24, 2021, the contents of which are incorporated herein by reference. Background Technology

[0003] One type of steam turbine is the dual-flow steam turbine described in Patent Document 1. This dual-flow steam turbine includes a first steam turbine section and a second steam turbine section. Both the first and second steam turbine sections include a rotor that rotates around an axis, a housing covering the rotor, multiple stationary blade segments fixed to the housing, a steam inlet pipe, and a flow-splitting component. Furthermore, for ease of explanation below, the direction in which the axis extends is defined as the axial direction. And, of the two sides in the axial direction, one side is designated as the first side, and the other side as the second side.

[0004] The first and second steam turbine sections share a steam inlet pipe and a flow divider. In the first steam turbine section, components other than the steam inlet pipe and the flow divider are arranged on a first side along the axial direction with the steam inlet pipe as a reference. In this first steam turbine section, a second side forms an upstream side along the axial direction, and a first side forms a downstream side along the axial direction. Similarly, in the second steam turbine section, components other than the steam inlet pipe are arranged on a second side with the steam inlet pipe as a reference. In the second steam turbine section, a first side forms an upstream side along the axial direction, and a second side forms a downstream side along the axial direction.

[0005] Each rotor in the first and second steam turbine sections has a rotor shaft extending along an axial direction centered on an axis, and multiple rows of moving blades fixed to the outer periphery of the rotor shaft and arranged along the axial direction. Each row of moving blades has multiple moving blades arranged circumferentially relative to the axis. One of multiple rows of stationary blades is positioned upstream of the axis of each row of moving blades. Each row of stationary blades has multiple stationary blades arranged circumferentially. Each stationary blade segment has a circumferentially extending outer ring and multiple stationary blades disposed radially inward of the outer ring. An outer ring groove is formed in the outer ring, recessed from radially inward relative to the axis toward radially outward, and extending circumferentially. Outer shrouds of the multiple stationary blades are embedded in the outer ring groove of the outer ring. The outer ring is fixed to the radially inward portion of the housing (or blade ring). The rotors of the first and second steam turbine sections are located on the same axis and connected to each other.

[0006] The stationary blade has a blade body with a cross-section that is radially perpendicular to the axis and is blade-shaped and extends radially, an inner shroud formed on the radially inner side of the blade body, and an outer shroud formed on the radially outer side of the blade body.

[0007] The flow divider connects the inner shrouds of the primary stationary blades in the first steam turbine section and the inner shrouds of the primary stationary blades in the second steam turbine section. This flow divider allows a portion of the steam flowing in from the steam inlet pipe to be guided to the primary stationary blades in the first steam turbine section, and the remaining portion of the steam flowing in from the steam inlet pipe to be guided to the primary stationary blades in the second steam turbine section.

[0008] The outer shroud of the primary stationary blade has a shroud body, a recessed portion, and a downstream extension. The shroud body has an outer gas path surface facing radially inward and connected to the blade body. The recessed portion protrudes radially outward from the shroud body. The recessed portion in the outer shroud is embedded in the outer ring groove of the primary outer ring. The downstream extension protrudes downstream of the axial direction from the shroud body. The downstream extension and the primary moving blade are radially opposed.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Utility Model Application Publication No. 60-082502 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] In steam turbines, from the perspective of turbine efficiency, the stationary blade segments, casing, and rotor are subject to design constraints. However, it is desirable for these components to meet turbine efficiency requirements and to offer a high degree of design freedom.

[0014] Therefore, the object of the present invention is to provide a technology that can meet requirements such as turbine efficiency and improve the design freedom of the casing.

[0015] Methods for solving problems

[0016] As an embodiment of the present invention for achieving the above-mentioned objectives, the primary stationary blade segment comprises:

[0017] An outer ring extends circumferentially relative to an axis; and a plurality of primary stationary blades are arranged and mounted circumferentially on the radially inner side of the outer ring relative to the axis. Of a first side and a second side in the axial direction of the extended axis, the second side forms an upstream side of the axis, and the first side forms a downstream side of the axis. Each of the plurality of primary stationary blades has: a blade body extending radially relative to the axis; an inner shroud formed on the radially inner side of the blade body; and an outer shroud formed on the radially outer side of the blade body relative to the axis. The blade body has: a leading edge forming an edge on the upstream side of the axis; and a trailing edge forming an edge on the downstream side of the axis. The inner shroud has an inner gas path surface facing the radially outer side and connected to the blade body. The outer shroud has: a shroud body having an outer gas path surface facing the radially inner side and connected to the blade body; and an embedded portion connected to the radially outer side of the shroud body. The embedded portion has: an embedded front end face facing upstream of the axis; an embedded rear end face facing downstream of the axis and having a back-to-back relationship with the embedded front end face; and an embedded bottom face facing radially outward and connecting the embedded front end face and the embedded rear end face. The outer ring has an outer ring groove, an outer ring gas path surface, an outer ring rear end face, and an outer ring outer peripheral surface for the outer shroud of each of the plurality of primary stationary blades to enter. The outer ring groove is recessed from the downstream end of the outer ring gas path surface towards the radially outward and extends circumferentially. The outer ring groove has: a groove front side facing downstream of the axis and facing the embedded front end face; a groove rear side facing upstream of the axis and facing the embedded rear end face; and a groove bottom surface facing radially inward and facing the embedded bottom face. The outer ring gas path surface has a surface that curves gradually from a position further upstream of the axis than the groove front side and further radially outward than the outer ring gas path surface, toward the radially inward side and downstream of the axis, and connects to the outer ring gas path surface. The outer ring rear end face is located further downstream of the axis than the outer ring groove and faces the downstream side of the axis. The outer ring outer peripheral surface faces the radially outward side and connects the radially outward edge of the outer ring gas path surface and the radially outward edge of the outer ring rear end face. The embedded front end face is located further upstream of the axis than the leading edge. The embedded rear end face is located further upstream of the axis than the trailing edge.

[0018] In the primary stator blade segment of this embodiment, the embedded front face of the embedded portion is located upstream of the axis than the leading edge of the blade body, and the embedded rear face of the embedded portion is located upstream of the axis than the trailing edge of the blade body. Therefore, in the primary stator blade of this embodiment, the embedded portion is displaced upstream of the axis relative to the blade body. Consequently, the groove rear face of the outer ring groove into which the embedded portion of the primary stator blade enters is located upstream of the axis than the trailing edge of the blade body, thus suppressing the outer ring rear face from being downstream of the axis relative to the primary stator blade. In other words, this embodiment reduces, or eliminates, the portion protruding downstream of the axis from the primary stator blade in the outer ring.

[0019] Therefore, this approach increases the design freedom of the housing with the outer ring installed. Because of this increased design freedom, a portion of the housing can also exist within the common region of the axial region where the primary moving blade exists and the radial region where the outer ring exists. If a portion of the housing can exist within this common region, it is not necessary to expand the axial distance between the primary stationary blade and the primary moving blade; a primary sealing ring that seals the gap between the housing and the primary moving blade can be installed within this portion of the housing.

[0020] Expanding the axial spacing between the primary stationary blades and the primary moving blades would likely decrease turbine efficiency. However, in this design, as described above, the primary sealing ring can be installed on a portion of the housing without expanding the axial spacing between the primary stationary blades and the primary moving blades. Therefore, this design satisfies requirements such as turbine efficiency and increases the design freedom of the housing.

[0021] As a static unit of the present invention for achieving the above-mentioned objectives, it comprises:

[0022] As one embodiment, a primary stationary blade segment and a blade ring are provided, wherein the primary stationary blade segment and a primary sealing ring are mounted. The blade ring has: a blade ring gas path surface facing the radially inward side; an outer ring mounting portion on which the outer ring is mounted; and a primary sealing ring mounting portion on which the primary sealing ring is mounted. The primary sealing ring mounting portion is recessed from the blade ring gas path surface toward the radially outward side and extends circumferentially. The entire outer ring mounting portion is located upstream of the axis than the primary sealing ring mounting portion.

[0023] As one embodiment of the present invention for achieving the above-mentioned objectives, a steam turbine comprises:

[0024] As a stationary unit of the aforementioned configuration: a steam inlet pipe; a rotor capable of rotating about the said axis; and a housing covering the outer periphery of the rotor. The housing has the blade ring. The steam inlet pipe is configured such that steam flows from the upstream side of the said axis between the outer periphery of the rotor and the inner periphery of the housing.

[0025] As an embodiment of the present invention for achieving the above-mentioned objectives, the primary stationary blade segment unit comprises:

[0026] The primary stationary blade segment of the aforementioned configuration comprises: a first primary stationary blade segment; a second primary stationary blade segment disposed at a distance from the first primary stationary blade segment on a second side; and a flow divider extending circumferentially and connecting the first and second primary stationary blade segments. The second primary stationary blade segment includes: a second outer ring extending circumferentially and having the same shape as the outer ring of the first primary stationary blade segment (i.e., the first outer ring), with the first side as the upstream side of the axis and the second side as the downstream side of the axis; and a plurality of second primary stationary blades arranged circumferentially on the radially inner side of the second outer ring, having the same shape as the plurality of primary stationary blades of the first primary stationary blade segment (i.e., the plurality of first primary stationary blades), with the first side as the upstream side of the axis and the second side as the downstream side of the axis. The flow divider includes: a first connecting portion connected to the inner shroud of each of the plurality of first primary stationary blades; a second connecting portion connected to the inner shroud of each of the plurality of second primary stationary blades; and a body connecting the first connecting portion and the second connecting portion. The main body has a gas path surface that extends radially outward along the axial direction and is connected to the inner gas path surface of each of the plurality of first primary stationary blades and the inner gas path surface of each of the plurality of second primary stationary blades.

[0027] As another embodiment of the present invention for achieving the above-mentioned objectives, the steam turbine comprises:

[0028] The primary stationary blade segment unit, as described in one embodiment, includes: a steam inlet pipe; a first rotor rotatable about the axis; a plurality of first downstream stationary blade rows arranged along the axis on the outer periphery of the first rotor; a first housing covering the outer periphery of the first rotor and housing the first primary stationary blade segment and the plurality of first downstream stationary blade rows; a second rotor rotatable about the axis; a plurality of second downstream stationary blade rows arranged along the axis on the outer periphery of the second rotor; and a second housing covering the outer periphery of the second rotor and housing the second primary stationary blade segment and the plurality of second downstream stationary blade rows. The first rotor and the second rotor are located on the same axis and connected to each other. The steam inlet pipe is positioned radially outward from the gas path direction of the splitter component and connects the first housing and the second housing.

[0029] Invention Effects

[0030] According to one aspect of the present invention, requirements such as turbine efficiency can be met, and the design freedom of the casing can be increased. Attached Figure Description

[0031] Figure 1 This is a cross-sectional view of a steam turbine in one embodiment of the present invention.

[0032] Figure 2 yes Figure 1 Enlarged view of Part II.

[0033] Figure 3 yes Figure 1 Enlarged view of Part III.

[0034] Figure 4 yes Figure 2 Enlarged view of part IV.

[0035] Figure 5 This is a perspective view of a primary stationary blade segment unit in one embodiment of the present invention.

[0036] Figure 6 yes Figure 5 Enlarged view of section VI.

[0037] Figure 7 yes Figure 5 An enlarged view of part VII. Detailed Implementation

[0038] The following is for reference. Figures 1 to 7 The embodiments of the steam turbine involved in this invention will be described in detail.

[0039] like Figure 1As shown, the steam turbine in this embodiment is a dual-flow steam turbine. This steam turbine has a first steam turbine section ST1 and a second steam turbine section ST2. Both the first steam turbine section ST1 and the second steam turbine section ST2 include a rotor 10 that rotates around an axis Ar, a housing 20 covering the rotor 10, multiple rows of stationary blades 50 mounted on the housing 20, a bearing 15, a steam inlet pipe 16, and a flow splitting component 71. The rotor 10 of the first steam turbine section ST1 and the rotor 10 of the second steam turbine section ST2 are located on the same axis Ar and are rotatably connected. Furthermore, for ease of explanation below, the direction in which the axis Ar extends is designated as the axial direction Da. And, of the two sides in the axial direction Da, one side is designated as the first side Da1, and the other side as the second side Da2.

[0040] The first steam turbine section ST1 and the second steam turbine section ST2 share a steam inlet pipe 16 and a flow divider 71. In the first steam turbine section ST1, components other than the steam inlet pipe 16 and the flow divider 71 are arranged on a first side Da1 in the axial direction Da, with the steam inlet pipe 16 as the reference. In the first steam turbine section ST1, a second side Da2 forms an upstream side Dau, and the first side Da1 forms a downstream side Dad. Similarly, in the second steam turbine section ST2, components other than the steam inlet pipe 16 and the flow divider 71 are arranged on a second side Da2, with the steam inlet pipe 16 as the reference. In the second steam turbine section ST2, the first side Da1 forms an upstream side Dau, and the second side Da2 forms a downstream side Dad. The first steam turbine section ST1 and the second steam turbine section ST2 have the same shape and structure. However, the upstream side Dau in the second steam turbine section ST2 and the upstream side Dau in the first steam turbine section ST1 are opposite sides in the axial direction Da.

[0041] like Figure 2 As shown, each rotor 10 in the first steam turbine section ST1 and the second steam turbine section ST2 has a rotor shaft 11 extending along the axial direction Da with the axis Ar as the center, and a plurality of moving blade rows 12 fixed to the outer periphery of the rotor shaft 11 and arranged along the axial direction Da. A bearing 15 rotatably supports the rotor shaft 11 at the Dad portion downstream of the axis of the rotor shaft 11 (see reference). Figure 1 Each moving blade row 12 has a plurality of moving blades 13 arranged circumferentially along axis Ar (Dc). Each moving blade 13 has a blade body with a blade-shaped cross-section perpendicular to the radial direction Dr relative to axis Ar and extending radially along Dr. A plurality of stationary blade rows 50 are arranged along the axial direction Da. Any one of the plurality of stationary blade rows 50 is positioned upstream of the axis of each moving blade row 12 at a position Dau. Each stationary blade row 50 has a plurality of stationary blades 51 arranged circumferentially along axis Dc.

[0042] The stationary blade 51 has a blade body 52, an inner shroud 53, and an outer shroud 55. The blade body 52 has a blade-shaped cross-section perpendicular to the radial direction Dr and extends along the radial direction Dr. The inner shroud 53 is disposed at the radially inner end Dri of the blade body 52. ​​The outer shroud 55 is disposed at the radially outer end Dro of the blade body 52. ​​The inner shroud 53 and the outer shroud 55 form part of a steam flow path 17 through which steam S flows. Therefore, the blade body 52 is disposed within this steam flow path 17.

[0043] Here, among the plurality of stationary blade rows 50 arranged along the axial direction Da, the stationary blade row 50 closest to the upstream side Dau of the axial direction is designated as the primary stationary blade row 50a. Furthermore, among the plurality of stationary blade rows 50 arranged along the axial direction Da, the plurality of stationary blade rows 50 other than the primary stationary blade row 50a are designated as subsequent stage stationary blade rows 50r. In this embodiment, the plurality of subsequent stage stationary blade rows 50r include a second stage stationary blade row 50b, a third stage stationary blade row 50c, a fourth stage stationary blade row 50d, a fifth stage stationary blade row 50e, and a sixth stage stationary blade row 50f (see reference). Figure 3 ) and 50g of the seventh-grade static leaflet (reference) Figure 3 ).

[0044] And, as Figure 1 As shown, the rotor 10 of the first steam turbine unit ST1 is designated as the first rotor 10f, and the rotor 10 of the second steam turbine unit ST2 is designated as the second rotor 10s. Figure 2 As shown, the primary stationary blade row 50a of the first steam turbine section ST1 is designated as the first primary stationary blade row 50af, and the primary stationary blade row 50a of the second steam turbine section ST2 is designated as the second primary stationary blade row 50as. The plurality of subsequent stage stationary blade rows 50r of the first steam turbine section ST1 are designated as the plurality of first subsequent stage stationary blade rows 50rf, and the plurality of subsequent stage stationary blade rows 50r of the second steam turbine section ST2 are designated as the plurality of second subsequent stage stationary blade rows 50rs. Furthermore, the housing 20 of the first steam turbine section ST1 is designated as the first housing 20f, and the housing 20 of the second steam turbine section ST2 is designated as the second housing 20s. As described above, the first steam turbine section ST1 and the second steam turbine section ST2 have the same shape and structure. Therefore, the first steam turbine section ST1 will be mainly described below. And, hereafter, when "first" and "second" are not distinguished, the respective constituent elements of the first steam turbine section ST1 and the second steam turbine section ST2 will be referred to.

[0045] Each casing 20 in the first steam turbine section ST1 and the second steam turbine section ST2 has an inner casing 21, an exhaust casing 22, and three blade rings 30. The three blade rings 30 are all cylindrical with the axis Ar as the center. Furthermore, the three blade rings 30 are arranged along the axial direction Da. Figure 2 As shown, the first blade ring 30a, which is the blade ring 30 closest to the upstream side of the axis (Dau) among the three blade rings 30, is equipped with a primary stationary blade row 50a, a second-stage stationary blade row 50b, a third-stage stationary blade row 50c, a fourth-stage stationary blade row 50d, and a fifth-stage stationary blade row 50e. Figure 3 As shown, a sixth-stage stationary blade row 50f is mounted on the second blade ring 30b, which is adjacent to the downstream side of the axis of the first blade ring 30a (Dad). A seventh-stage stationary blade row 50g is mounted on the third blade ring 30c, which is adjacent to the downstream side of the axis of the second blade ring 30b (Dad). Each of the three blade rings 30 has a semi-circular upper blade ring forming a portion higher than the axis Ar and a semi-circular lower blade ring forming a portion lower than the axis Ar.

[0046] like Figure 1 As shown, the inner casing 21 is cylindrical with axis Ar as its center. Multiple blade rings 30 are installed on the inner circumferential side of the inner casing 21. The exhaust casing 22 has a diffuser 23 and a downstream end plate 24, an upstream end plate 25, and a circumferential plate 26.

[0047] The diffuser 23 is annular relative to the axis Ar, and forms a diffuser space 23s that gradually expands radially outward toward the downstream side Dad of the axis. Steam S passing through the last stage moving blade row 12g of the rotor 10 flows into the diffuser space 23s. In addition, the last stage moving blade row 12g is the moving blade row that is located closest to the downstream side Dad of the axis among the multiple moving blade rows 12.

[0048] The exhaust casing 22 has an exhaust port 27. This exhaust port 27 opens radially outward (Dro) and vertically downward. A condenser C, which converts steam S back into water, is connected to this exhaust port 27. The downstream end plate 24, upstream end plate 25, and peripheral plate 26 of the exhaust casing 22 form an exhaust space 22s through which steam S passing through the diffuser space 23s flows. This exhaust space 22s extends circumferentially (Dc) relative to the axis Ar on the outer periphery of the diffuser 23, guiding the steam S flowing into the diffuser space 23s to the exhaust port 27.

[0049] The downstream end plate 24 defines the edge of the exhaust space 22s downstream of the axis Da. This downstream end plate 24 is substantially perpendicular to the axis Ar. The portion of the downstream end plate 24 that is higher than the axis Ar has a generally semi-circular shape when viewed from the axial direction Da. On the other hand, the portion of the downstream end plate 24 that is lower than the axis Ar has a generally rectangular shape when viewed from the axial direction Da. The lower edge of this downstream end plate 24 forms part of the edge of the exhaust port 27.

[0050] The upstream end plate 25 is positioned further upstream of the diffuser 23 on the axial side (Dau). This upstream end plate 25 defines the edge of the exhaust space 22s on the axial side (Dau). This upstream end plate 25 is substantially perpendicular to the axis Ar. Therefore, this upstream end plate 25 is spaced apart from the downstream end plate 24 in the axial direction Da. An inner housing 21 is connected to the radially inner edge (Dri) of the upstream end plate 25. The lower edge of the upstream end plate 25 forms part of the edge of the exhaust port 27.

[0051] The side circumferential plate 26 connects to the radially outer edge (Dro) of the downstream side end plate 24 and the radially outer edge (Dro) of the upstream side end plate 25, and extends along the axial direction (Da) and circumferentially (Dc) with the axis (Ar) as the center to define the radially outer edge portion of the exhaust space 22s (Dro). The side circumferential plate 26 has a semi-cylindrical shape with a semi-cylindrical upper side. The lower edge of the side circumferential plate 26 forms part of the edge of the exhaust port 27.

[0052] The exhaust casing 22 of the first steam turbine section ST1 and the exhaust casing 22 of the second steam turbine section ST2 are connected to each other to form an integrated unit.

[0053] The steam inlet pipe 16 is cylindrical with the pipe axis Ap as its center. The pipe axis Ap passes through the midpoint between the first primary stationary blade row 50af and the second primary stationary blade row 50as in the axial direction Da and extends vertically. The steam inlet pipe 16 is positioned higher than the axis Ap. The inner casing 21 and the side peripheral plate 26 of the first steam turbine section ST1 are connected to the first side Da1 of the steam inlet pipe 16. Furthermore, the inner casing 21 and the side peripheral plate 26 of the second steam turbine section ST2 are connected to the second side Da2 of the steam inlet pipe 16.

[0054] like Figure 2 and Figure 4As shown, the first blade ring 30a has a blade ring gas path surface 32 facing the radially inward side Dri, an outer ring mounting portion 33a, a primary sealing ring mounting portion 36a, a second-stage stationary blade row mounting portion 33b, a second-stage sealing ring mounting portion 36b, a third-stage stationary blade row mounting portion 33c, a third-stage sealing ring mounting portion 36c, a fourth-stage stationary blade row mounting portion 33d, a fourth-stage sealing ring mounting portion 36d, a fifth-stage stationary blade row mounting portion 33e, and a fifth-stage sealing ring mounting portion 36e. The outer ring mounting portion 33a, the primary sealing ring mounting portion 36a, the second-stage stationary blade row mounting portion 33b, the second-stage sealing ring mounting portion 36b, the third-stage stationary blade row mounting portion 33c, the third-stage sealing ring mounting portion 36c, the fourth-stage stationary blade row mounting portion 33d, the fourth-stage sealing ring mounting portion 36d, the fifth-stage stationary blade row mounting portion 33e, and the fifth-stage sealing ring mounting portion 36e are arranged in the above order from the upstream side Dau of the axis towards the downstream side Dad of the axis. Furthermore, the outer ring mounting portion 33a, the primary sealing ring mounting portion 36a, the second-stage stationary blade row mounting portion 33b, the second-stage sealing ring mounting portion 36b, the third-stage stationary blade row mounting portion 33c, the third-stage sealing ring mounting portion 36c, the fourth-stage stationary blade row mounting portion 33d, the fourth-stage sealing ring mounting portion 36d, the fifth-stage stationary blade row mounting portion 33e, and the fifth-stage sealing ring mounting portion 36e are all recessed from the gas path surface 32 of the blade ring toward the radially outward direction.

[0055] As described above, the first blade ring 30a has a semi-circular upper blade ring 30au forming a portion higher than the axis Ar and a semi-circular lower blade ring forming a portion lower than the axis Ar. The ends of the first upper blade ring 30au and the first lower blade ring on the circumferential direction Dc are connected by blade ring connecting bolts 32b. Bolt holes 31 for inserting the blade ring connecting bolts 32b are formed in the regions on the axial direction Da of the primary sealing ring mounting portions 36a disposed at both ends of the first upper blade ring 30au and the first lower blade ring, and in the region radially outward Dro of the primary sealing ring mounting portions 36a.

[0056] like Figure 4 As shown, the outer ring mounting portion 33a has a mounting side surface 34 and a mounting inner circumferential surface 35. The mounting side surface 34 extends radially outward from a position on the upstream side (Dau) of the blade ring gas path surface 32, which is further upstream on the axis than the primary sealing ring mounting portion 36a, and extends circumferentially (Dc). The mounting inner circumferential surface 35 extends radially outward from the edge of the mounting side surface 34 on the upstream side (Dau) of the axis, and extends circumferentially (Dc). The outer ring 61 of the primary stationary blade segment 60 is mounted on this outer ring mounting portion 33a.

[0057] The primary stationary blade segment 60 has the aforementioned outer ring 61 extending circumferentially Dc with axis Ar as the center, a primary stationary blade row 50a mounted on the radially inner side Dri of the outer ring 61, a caulking member 63, and a plurality of fixing nuts 64. The stationary unit 80 is constituted by the primary stationary blade segment 60 and the first blade ring 30a.

[0058] like Figure 5 As shown, the outer ring 61 of the primary stationary blade segment 60 also has a semi-circular upper outer ring 61u forming a portion higher than the axis Ar and a semi-circular lower outer ring 61d forming a portion lower than the axis Ar. Figure 5 and Figure 7 As shown, the ends on the circumferential direction Dc of the upper outer ring 61u and the ends on the circumferential direction Dc of the lower outer ring 61d are connected by outer ring connecting bolts 62. The aforementioned primary stationary blade row 50a is composed of a plurality of primary stationary blades 51a mounted on the upper outer ring 61u and a plurality of primary stationary blades 51a mounted on the lower outer ring 61d. Furthermore, the upper outer ring 61u is mounted on the outer ring mounting portion 33a in the first upper blade ring 30au, and the lower outer ring 61d is mounted on the outer ring mounting portion 33a in the first lower blade ring. Support plates 69 protruding radially outward from the lower outer ring 61d are provided at both ends on the circumferential direction Dc of the lower outer ring 61d. The lower outer ring 61d, which is connected to the upper outer ring 61u by the outer ring connecting bolts 62, is supported on the first lower blade ring by the support plates 69.

[0059] As described above, the primary stationary blade 51a has a blade body 52, an inner shroud 53, and an outer shroud 55. Figure 4 As shown, the blade body 52 has a leading edge 52f forming the edge of the upstream side of the axis Dau and a trailing edge 52r forming the edge of the downstream side of the axis Dad.

[0060] The inner shroud 53 of the primary stationary blade 51a has an inner gas path surface 53p, a gas path opposite surface 53q, and a connecting groove 53g. The inner gas path surface 53p faces radially outward (Dro) and is connected to the blade body 52. ​​This inner gas path surface 53p defines a portion of the steam flow path 17. The gas path opposite surface 53q faces radially inward (Dri) and has a back-to-back relationship with the inner gas path surface 53p. The connecting groove 53g is recessed from the gas path opposite surface 53q towards radially outward (Dro) and extends circumferentially (Dc). The connecting groove 53g is formed such that its width gradually increases in the axial direction (Da) as it faces radially outward (Dro). That is, the connecting groove 53g is a dovetail groove.

[0061] The outer shroud 55 of the primary stationary blade 51a has a shroud body 56 and an embedded portion 57 connected to the radially outer Dro of the shroud body 56. The shroud body 56 has an outer gas path surface 56p, a shroud front end surface 56f, and a shroud rear end surface 56r. The outer gas path surface 56p faces the radially inner Dri and is connected to the blade body 52. ​​The outer gas path surface 56p is a surface that defines a portion of the steam flow path 17. The shroud front end surface 56f faces the upstream side Dau of the axis and extends radially outward from the edge of the upstream side Dau of the outer gas path surface 56p towards the radially outer Dro. The shroud rear end surface 56r faces the downstream side Dad of the axis and extends radially outward from the edge of the downstream side Dad of the outer gas path surface 56p towards the radially outer Dro. The embedded portion 57 has an embedded front end surface 57f, an embedded rear end surface 57r, an embedded bottom surface 57b, and an engagement groove 57g. The embedded front end face 57f faces upstream of the axis (Dau) and is located further upstream of the axis than the leading edge 52f of the blade body 52. ​​The embedded rear end face 57r faces downstream of the axis (Dad) and is back-to-back with the embedded front end face 57f, located further upstream of the axis than the trailing edge 52r of the blade body 52. ​​The embedded bottom face 57b faces radially outward (Dro) and connects the embedded front end face 57f and the embedded rear end face 57r. The engaging groove 57g is recessed from the embedded rear end face 57r towards the upstream axis (Dau) and extends circumferentially (Dc).

[0062] The outer ring 61 has an outer ring groove 65 for the outer shroud 55 of each of the plurality of primary stationary blades 51a to enter, an outer ring gas path surface 61p, an outer ring rear end surface 61r, and an outer ring outer peripheral surface 61o. The outer ring groove 65 has a groove front surface 65f facing downstream of the axis (Dad) and opposite to the embedded front end surface 57f, a groove rear surface 65r facing upstream of the axis (Dau) and opposite to the embedded rear end surface 57r, a groove bottom surface 65b facing radially inward (Dri) and opposite to the embedded bottom surface 57b, and a protrusion 65c. The protrusion 65c protrudes from the groove rear surface 65r toward upstream of the axis (Dau) and extends circumferentially (Dc). The protrusion 65c is embedded in each of the engagement grooves 57g of the embedded portion 57 in the plurality of primary stationary blades 51a. The outer gas path surface 61p has a surface that curves gradually from a position further upstream on the axis than the tank front side 65f (Dau) and further radially outward (Dro) than the tank bottom surface 65b, toward the radially inward (Dri) and towards the downstream side (Dad) of the axis, and connects to the outer gas path surface 56p. Alternatively, the outer gas path surface 61p may also gradually extend from a position further upstream on the axis than the tank front side 65f (Dau) and further radially outward (Dro) than the tank bottom surface 65b, toward the radially inward (Dri) and towards the downstream side (Dad) of the axis. The aforementioned outer ring groove 65 is recessed from the downstream side Dad of the outer ring gas path surface 61p toward the radially outward Dro and extends circumferentially Dc. The outer ring rear end face 61r faces the downstream side Dad and is located further downstream than the outer ring groove 65. The outer ring rear end face 61r and the mounting side face 34 of the first blade ring 30a are opposite each other in the axial direction Da. The outer ring outer peripheral surface 61o faces the radially outward Dro and connects the edge of the radially outward Dro of the outer ring gas path surface 61p and the edge of the radially outward Dro of the outer ring rear end face 61r. The outer ring outer peripheral surface 61o and the mounting inner peripheral surface 35 of the first blade ring 30a are opposite each other in the radial direction Dr.

[0063] The maximum distance *do* along the axial direction *Da* between the groove rear side 65r in the outer ring 61 and the outer ring rear end face 61r is less than the minimum distance *ds* along the axial direction *Da* between the embedded front end face 57f and the embedded rear end face 57r in the outer shield 55. Furthermore, the outer ring rear end face 61r and the shield rear end face 56r are on the same horizontal plane. This same horizontal plane includes not only the case where the outer ring rear end face 61r and the shield rear end face 56r are located on the same virtual plane, but also the case where a first virtual plane containing the outer ring rear end face 61r and a second virtual plane containing the shield rear end face 56r are parallel to each other, and the distance between the first virtual plane and the second virtual plane is, for example, within 2 mm.

[0064] The outer ring 61 also has a receiving space forming part 67. The receiving space forming part 67 is connected to the radially inner end of the groove front side 65f, Dri. The receiving space forming part 67, together with the outer guards 55 of the plurality of primary stationary blades 51a, forms a receiving space 67s for the caulking member 63 to enter. The radially inner Dri of the receiving space 67s is open.

[0065] The accommodating space forming section 67 has a space bottom surface 67b, a space inner surface 67r, a space bottom opposing surface 67o, and a space side surface 67p. The space bottom surface 67b faces radially inward Dri and extends circumferentially Dc, extending from the end of the radially inward Dri of the front side surface 65f towards the upstream side Dau of the axis. The space inner surface 67r faces radially downstream Dad and extends circumferentially Dc, extending from the end of the upstream side Dau of the space bottom surface 67b towards the radially inward Dri. The space bottom opposing surface 67o faces radially outward Dro and extends circumferentially Dc, extending from the end of the radially inward Dri of the space inner surface 67r towards the downstream side Dad of the axis. This space bottom opposing surface 67o is opposite the space bottom surface 67b in the radial Dr direction. The spatial side 67p faces downstream of the axis Dad and extends circumferentially Dc, extending radially inward from the end of Dad downstream of the spatial bottom opposing surface 67o toward the radially inward Dri. The radially inward end of the spatial side 67p Dri forms part of the edge of the opening 68 of the accommodating space 67s.

[0066] The receiving space 67s is defined by the surfaces 67b, 67o, 67p, and 67r of the receiving space forming portion 67 and the outer protective cover 55 that enters the outer ring groove 65. The cross-sectional shape of the receiving space 67s perpendicular to the circumferential direction Dc is L-shaped. The caulking member 63 is formed of a metal that is softer than the metal forming the stationary blade 51. After the outer protective covers 55 of the plurality of primary stationary blades 51a are placed into the outer ring groove 65, the caulking member 63 is inserted into the receiving space 67s through the opening 68. At this time, the caulking member 63 is struck with a hammer or the like to make it enter the receiving space 67s. If the caulking member 63 falls into the receiving space 67s, it contacts the surfaces 67b, 67o, 67p, and 67r of the receiving space forming portion 67 and the outer protective cover 55. Therefore, the cross-sectional shape of the sealant 63, perpendicular to the circumferential direction Dc, is L-shaped so that it falls into the L-shaped receiving space 67s. Additionally, a portion of the sealant 63 protrudes from the opening 68 of the receiving space 67s. The sealant 63 serves to constrain the relative movement of the plurality of primary stationary blades 51a with respect to the outer ring groove 65 along the axial direction Da and radial direction Dr.

[0067] The aforementioned retaining nut 64 is screwed in across the primary stationary blades 51a at the circumferential end of the plurality of primary stationary blades 51a mounted on the upper outer ring 61u, and across the upper outer ring 61u. Furthermore, other retaining nuts 64 are screwed in across the primary stationary blades 51a at the circumferential end of the plurality of primary stationary blades 51a mounted on the lower outer ring 61d, and across the lower outer ring 61d. These retaining nuts 64 serve the function of constraining the relative movement of the plurality of primary stationary blades 51a with respect to the outer ring groove 65 along the circumferential direction Dc.

[0068] like Figure 2 As shown, a primary sealing ring 40a is installed in the primary sealing ring mounting portion 36a. A second-stage sealing ring 40b is installed in the second-stage sealing ring mounting portion 36b. A third-stage sealing ring 40c is installed in the third-stage sealing ring mounting portion 36c. A fourth-stage sealing ring 40d is installed in the fourth-stage sealing ring mounting portion 36d. A fifth-stage sealing ring 40e is installed in the fifth-stage sealing ring mounting portion 36e. The primary moving blade row 12a of the plurality of moving blade rows 12 of the rotor 10 is radially opposed to the primary sealing ring 40a. The second-stage moving blade row 12b of the plurality of moving blade rows 12 of the rotor 10 is radially opposed to the second-stage sealing ring 40b. The third-stage moving blade row 12c of the plurality of moving blade rows 12 of the rotor 10 is radially opposed to the third-stage sealing ring 40c. The fourth-stage moving blade row 12d of the plurality of moving blade rows 12 of the rotor 10 is opposite to the fourth-stage sealing ring 40d in the radial direction Dr. The fifth-stage moving blade row 12e of the plurality of moving blade rows 12 of the rotor 10 is opposite to the fifth-stage sealing ring 40e in the radial direction Dr.

[0069] like Figure 4 As shown, each sealing ring has a cylindrical sealing ring base 41 centered on axis Ar, multiple fins 42 protruding radially inward (Dri) from the inner circumference of the sealing ring base 41 and extending circumferentially (Dc), and a pair of base support feet 43 protruding radially outward (Dro) from the outer circumference of the sealing ring base 41 and extending circumferentially (Dc). Each sealing ring mounting portion 36a-36b has a base receiving groove 37 recessed from the gas path surface 32 of the blade ring towards the radially outward (Dro) and extending circumferentially (Dc), and a foot receiving groove 38 recessed from the bottom surface of the base receiving groove 37 towards the radially outward (Dro) and extending circumferentially (Dc). The sealing ring base 41 is received in the base receiving groove 37 in a manner that allows it to move radially (Dr). A pair of base support feet 43 are received in the foot receiving groove 38 in a manner that allows them to move radially (Dr).

[0070] The aforementioned outer ring mounting portion 33a is located on the upstream side of the axis, Dau, which is further from the primary sealing ring mounting portion 36a described above.

[0071] A second-stage stationary blade row 50b is installed in the second-stage stationary blade row mounting section 33b. A third-stage stationary blade row 50c is installed in the third-stage stationary blade row mounting section 33c. A fourth-stage stationary blade row 50d is installed in the fourth-stage stationary blade row mounting section 33d. A fifth-stage stationary blade row 50e is installed in the fifth-stage stationary blade row mounting section 33e. Each stationary blade row mounting section 33b to 33e has a blade annular groove 39 into which the outer shroud 55 of the stationary blade 51 is inserted. Furthermore, the constraint structure of the outer shroud 55 relative to the blade annular groove 39 is substantially the same as the constraint structure of the outer shroud 55 of the primary stationary blade 51a relative to the outer ring groove 65. That is, the outer shroud 55 is constrained relative to the blade annular groove 39 by using a caulking member and connecting bolts.

[0072] Here, as Figure 2 and Figure 5As shown, the primary stationary blade segment 60 of the first steam turbine section ST1 is designated as the first primary stationary blade segment 60f, and the primary stationary blade segment 60 of the second steam turbine section ST2 is designated as the second primary stationary blade segment 60s. The second primary stationary blade segment 60s is arranged at a distance from the first primary stationary blade segment 60f on the second side Da2. The second primary stationary blade segment 60s has the same shape and structure as the first primary stationary blade segment 60f. Therefore, the second primary stationary blade segment 60s has a second outer ring 61s with the same shape and structure as the outer ring 61, i.e., the first outer ring 61f, in the first primary stationary blade segment 60f; multiple second primary stationary blades 51as with the same shape and structure as the multiple first primary stationary blades 51af of the multiple primary stationary blades 51a in the first primary stationary blade segment 60f; a caulking member 63 with the same shape and structure as the caulking member 63 in the first primary stationary blade segment 60f; and multiple fixing nuts 64. However, in the second primary stationary blade segment 60s, the upstream side Dau of the axis is the first side Da1 in the axial direction Da, and the downstream side Dad of the second primary stationary blade segment 60s is the second side Da2 in the axial direction Da.

[0073] The primary stationary blade segment unit 70 includes the aforementioned flow-diverting component 71 and the first primary stationary blade segment 60f and the second primary stationary blade segment 60s described above. The flow-diverting component 71 is cylindrical about the axis Ar and connects the first primary stationary blade segment 60f and the second primary stationary blade segment 60s. Figure 5 As shown, the flow splitter 71 has an upper flow splitter 71u forming a portion higher than the axis Ar and a lower flow splitter 71d forming a portion lower than the axis Ar. The upper flow splitter 71u connects to a plurality of first primary stationary blades 51af mounted on the upper outer ring 61u of the first primary stationary blade segment 60f and a plurality of second primary stationary blades 51as mounted on the upper outer ring 61u of the second primary stationary blade segment 60s. The lower flow splitter 71d connects to a plurality of first primary stationary blades 51af mounted on the lower outer ring 61d of the first primary stationary blade segment 60f and a plurality of second primary stationary blades 51as mounted on the lower outer ring 61d of the second primary stationary blade segment 60s. Both the upper flow splitter 71u and the lower flow splitter 71d have a first flow splitter 71f, a second flow splitter 71s, and a connecting member 76.

[0074] like Figure 2 , Figure 4 and Figure 6As shown, the first diverter 71f has a first connecting portion 72f connected to the inner shroud 53 of each of the plurality of first primary stationary blades 51af and a first body 73f extending from the first connecting portion 72f toward a second side Da2. The first body 73f has a first gas path surface 74f and a first flange 75f. The first gas path surface 74f extends radially outward Dro from the first connecting portion 72f toward the second side Da2 in the axial direction Da. The first gas path surface 74f is connected to the inner gas path surface 53p of each of the plurality of first primary stationary blades 51af. The first flange 75f protrudes radially inward Dri from the end of the second side Da2 of the first gas path surface 74f. The first connecting portion 72f has a protrusion 72fc that is embedded in a connecting groove 53g in the inner shroud 53 of each of the plurality of first primary stationary blades 51af. Similar to the shape of the connecting groove 53g, the protrusion 72fc is formed such that its convex width in the axial direction Da gradually increases as it moves radially outward Dro.

[0075] The second diverter 71s has a second connecting portion 72s connected to the inner shroud 53 of each of the plurality of second primary stationary blades 51as, and a second body 73s extending from the second connecting portion 72s toward a first side Da1. The second body 73s has a second gas path surface 74s and a second flange 75s. The second gas path surface 74s extends radially outward from the second connecting portion 72s toward the first side Da1 in the axial direction Da. The second gas path surface 74s is connected to the inner gas path surface 53p of each of the plurality of second primary stationary blades 51as. The second flange 75s protrudes radially inward from the end of the first side Da1 of the second gas path surface 74s. The second connecting portion 72s has a protrusion 72sc that is embedded in a connecting groove 53g in the inner shroud 53 of each of the plurality of second primary stationary blades 51as. Similar to the shape of the connecting groove 53g, the protrusion 72sc is formed such that its convex width in the axial direction Da gradually increases as it moves radially outward toward Dro. In addition, the main body 73 of the diversion component 71 is composed of the first main body 73f and the second main body 73s.

[0076] The first flange 75f of the first diversion component 71f and the second flange 75s of the second diversion component 71s are connected by bolts, which serve as connecting members, through a spacer 77.

[0077] The central position of the flow divider 71 along the axial direction Da is approximately the same as the position along the axial direction Da of the aforementioned pipe axis Ap. Furthermore, the flow divider 71 is positioned to separate from the steam inlet pipe 16 radially inward (Dri). In other words, the steam inlet pipe 16 is positioned to separate from the gas path surfaces 74f and 74s of the flow divider 71 radially outward (Dro).

[0078] Steam S passing through steam inlet pipe 16 is split by gas path surfaces 74f and 74s of splitting member 71 into a first side Da1 and a second side Da2 in the axial direction Da. Steam S toward the first side Da1 flows into the steam flow path 17 of the first steam turbine section ST1. And steam S toward the second side Da2 flows into the steam flow path 17 of the second steam turbine section ST2.

[0079] As described above, in the primary stationary blade segment 60 of this embodiment, the front end face 57f of the embedded portion 57 in the primary stationary blade 51a is located upstream of the axis (Dau) than the leading edge 52f of the blade body 52 in the primary stationary blade 51a, and the rear end face 57r of the embedded portion 57 is located upstream of the axis (Dau) than the trailing edge 52r of the blade body 52. ​​Therefore, in the primary stationary blade 51a of the primary stationary blade segment 60 of this embodiment, the embedded portion 57 is displaced upstream of the axis (Dau) relative to the blade body 52. ​​Therefore, the rear side face 65r of the outer ring groove 65 into which the embedded portion 57 of the primary stationary blade 51a enters is located upstream of the axis (Dau) than the trailing edge 52r of the blade body 52, which can suppress the rear end face 61r of the outer ring from being located downstream of the axis (Dad) relative to the primary stationary blade 51a. In other words, in this embodiment, the portion of the outer ring 61 that protrudes downstream of the primary stationary blade 51a towards the axis (Dad) can be reduced, or the portion of the outer ring 61 that protrudes downstream of the primary stationary blade 51a towards the axis (Dad) can be eliminated. Furthermore, in this embodiment, the rear end face 61r of the outer ring and the rear end face 56r of the shroud are at the same horizontal plane, therefore, there is no portion of the outer ring 61 that protrudes downstream of the primary stationary blade 51a towards the axis (Dad).

[0080] Therefore, in this embodiment, the design freedom of the first blade ring 30a (part of the housing 20) on which the outer ring 61 is mounted can be increased. Thus, since the design freedom of the first blade ring 30a can be increased, a portion of the first blade ring 30a can also exist in the common region of the axial direction Da region where the primary moving blade row 12a exists and the radial Dr region where the outer ring 61 exists. Therefore, in this embodiment, by having a portion of the first blade ring 30a exist in this common region, a primary sealing ring 40a that seals the gap between the primary stationary blade 51a and the primary moving blade 13 can be mounted on a portion of the first blade ring 30a without expanding the axial direction Da interval between the primary stationary blade 51a and the primary moving blade 13.

[0081] If the axial distance Da between the primary stationary blade 51a and the primary moving blade 13 is increased, the turbine efficiency is likely to decrease. However, in this embodiment, as described above, the primary sealing ring 40a can be installed on a portion of the first blade ring 30a without increasing the axial distance Da between the primary stationary blade 51a and the primary moving blade 13. Therefore, in this embodiment, requirements such as turbine efficiency can be met, and the design freedom of the first blade ring 30a, which is part of the housing 20, is increased.

[0082] If the primary sealing ring 40a can be installed on a portion of the first blade ring 30a instead of a portion of the outer ring 61, the radial width Dr of the primary sealing ring mounting portion 36a in the blade ring 30 can be increased, allowing the primary sealing ring 40a to be movably mounted relative to the blade ring 30 along the radial width Dr. Furthermore, even with increased radial width Dr of the primary sealing ring mounting portion 36a, the bolt hole 31 for the blade ring connecting bolt 32b to be inserted can be formed in the radially outer region Dro of the primary sealing ring mounting portion 36a in the first blade ring 30a.

[0083] In this embodiment, even without welding the outer cover 55 of each of the plurality of first primary stationary blades 51af to the first outer ring 61f, the outer cover 55 of each of the plurality of first primary stationary blades 51af can be securely installed to the first outer ring 61f using the caulking member 63 and the fixing nut 64. Furthermore, even without welding the outer cover 55 of each of the plurality of second primary stationary blades 51as to the second outer ring 61s, the outer cover 55 of each of the plurality of second primary stationary blades 51as can be securely installed to the second outer ring 61s using the caulking member 63 and the fixing nut 64. Moreover, in this embodiment, even without welding the inner cover 53 of each of the plurality of first primary stationary blades 51af to the diverter 71, the inner cover 53 of each of the plurality of first primary stationary blades 51af can be securely connected to the diverter 71. Furthermore, in this embodiment, even without welding the inner shroud 53 and the diversion component 71 of each of the plurality of second primary stationary blades 51as together, the inner shroud 53 and the diversion component 71 of each of the plurality of second primary stationary blades 51as can be securely connected.

[0084] Therefore, in this embodiment, the components constituting the primary stationary blade segment unit 70 can be securely connected even without welding them together.

[0085] Furthermore, in this embodiment, the diversion component 71 is divided into a first diversion component 71f and a second diversion component 71s. Therefore, it is not necessary to perform the operations of inserting the protrusion 72fc of the first connecting portion 72f in the first diversion component 71f into the connecting groove 53g of each of the plurality of first primary stationary blades 51af and the operations of inserting the protrusion 72sc of the second connecting portion 72s in the second diversion component 71s into the connecting groove 53g of each of the plurality of second primary stationary blades 51as in parallel. Therefore, in this embodiment, the first connecting portion 72f of the diversion component 71 can be easily connected to the plurality of first primary stationary blades 51af, and the second connecting portion 72s of the diversion component 71 can be easily connected to the plurality of second primary stationary blades 51as.

[0086] In the middle portion of the diversion component 71 along the axial direction Da, there are a first flange 75f of the first diversion component 71f and a second flange 75s of the second diversion component 71s. Therefore, in the middle portion of the main body 73 in the diversion component 71 along the axial direction Da, these flanges 75f and 75s function as reinforcing ribs of the main body 73. Therefore, in this embodiment, the rigidity of the diversion component 71 can be improved.

[0087] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Various additions, modifications, substitutions, and partial deletions may be made without departing from the conceptual idea and spirit of the present invention derived from the content specified in the technical solution and its equivalents.

[0088] Postscript

[0089] The primary stationary blade segment in the above embodiments can be understood as follows.

[0090] (1) The primary stationary blade segment in the first method has:

[0091] An outer ring 61 extends along a circumferential direction Dc relative to the axis Ar; and a plurality of primary stationary blades 51a are arranged and mounted along the circumferential direction Dc on the radially inner side Dri of the outer ring 61 relative to the axis Ar.

[0092] Of the first side Da1 and the second side Da2 along the axial direction Da extending from the axis Ar, the second side Da2 forms the upstream side Dau, and the first side Da1 forms the downstream side Dad. The plurality of primary stationary blades 51a each have: a blade body 52 extending radially Dr relative to the axis Ar; an inner shroud 53 formed on the radially inner side Dri of the blade body 52; and an outer shroud 55 formed on the radially outer side Dro of the blade body 52 relative to the axis Ar. The blade body 52 has: a leading edge 52f forming the edge of the upstream side Dau; and a trailing edge 52r forming the edge of the downstream side Dad. The inner shroud 53 has an inner gas path surface 53p facing the radially outer side Dro and connected to the blade body 52. The outer shield 55 includes: a shield body 56 having an outer gas path surface 56p facing the radially inward side Dri and connected to the blade body 52; and an embedded portion 57 connected to the radially outward side Dro of the shield body 56. The embedded portion 57 includes: an embedded front end face 57f facing the upstream side Dau of the axis; an embedded rear end face 57r facing the downstream side Dad of the axis and having a back-to-back relationship with the embedded front end face 57f; and an embedded bottom face 57b facing the radially outward side Dro and connecting the embedded front end face 57f and the embedded rear end face 57r. The outer ring 61 has an outer ring groove 65, an outer ring gas path surface 61p, an outer ring rear end face 61r, and an outer ring outer peripheral surface 61o for each of the plurality of primary stationary blades 51a to enter the outer shield 55. The outer ring groove 65 is recessed from the downstream side Dad of the outer ring gas path surface 61p toward the radially outer side Dro and extends along the circumferential direction Dc. The outer ring groove 65 has: a groove front side 65f, facing the downstream side Dad and opposite the embedded front end face 57f; a groove rear side 65r, facing the upstream side Dau and opposite the embedded rear end face 57r; and a groove bottom surface 65b, facing the radially inner side Dri and opposite the embedded bottom surface 57b. The outer ring gas path surface 61p has a surface that curves gradually from a position closer to the upstream side Dau than the groove front side 65f and closer to the radially outer side Dro than the outer gas path surface 56p, toward the radially inner side Dri and toward the downstream side Dad, and connects to the outer gas path surface 56p. The outer ring rear end face 61r is located further downstream of the axis on the Dad than the outer ring groove 65, and faces the downstream side of the axis on the Dad. The outer ring outer peripheral surface 61o faces the radially outer Dro, and connects the edge of the radially outer Dro of the outer ring gas path surface 61p and the edge of the radially outer Dro of the outer ring rear end face 61r.The embedded front end face 57f is located at a position Dau further upstream on the axis than the leading edge 52f. The embedded rear end face 57r is located at a position Dau further upstream on the axis than the trailing edge 52r.

[0093] In the primary stationary blade segment 60 of this embodiment, the embedded front face 57f of the embedded portion 57 in the primary stationary blade 51a is located upstream of the axis (Dau) than the leading edge 52f of the blade body 52 in the primary stationary blade 51a, and the embedded rear face 57r of the embedded portion 57 is located upstream of the axis (Dau) than the trailing edge 52r of the blade body 52. ​​Therefore, in the primary stationary blade 51a of the primary stationary blade segment 60 of this embodiment, the embedded portion 57 is displaced upstream of the axis (Dau) relative to the blade body 52. ​​Consequently, the groove rear face 65r in the outer ring groove 65 into which the embedded portion 57 of the primary stationary blade 51a enters is located upstream of the axis (Dau) than the trailing edge 52r of the blade body 52, which can suppress the outer ring rear face 61r from being located downstream of the axis (Dau) relative to the primary stationary blade 51a. In other words, in this method, the portion of the outer ring 61 that protrudes downstream of the primary stationary blade 51a towards the axis can be reduced, or the portion of the outer ring 61 that protrudes downstream of the primary stationary blade 51a towards the axis can be eliminated.

[0094] Therefore, this approach increases the design freedom of the housing 20 on which the outer ring 61 is mounted. Because of this increased design freedom, a portion of the housing 20 can exist within the common region of the area along the axial direction Da where the primary moving blade 13 is located and the area along the radial direction Dr where the outer ring 61 is located. If a portion of the housing 20 can exist within this common region, it is not necessary to expand the axial distance Da between the primary stationary blade 51a and the primary moving blade 13, and a primary sealing ring 40a that seals the gap between the housing 20 and the primary moving blade 13 can be installed within this portion of the housing 20.

[0095] If the axial distance Da between the primary stationary blade 51a and the primary moving blade 13 is increased, the turbine efficiency is likely to decrease. However, in this embodiment, as described above, the primary sealing ring 40a can be installed on a portion of the housing 20 without increasing the axial distance Da between the primary stationary blade 51a and the primary moving blade 13. Therefore, in this embodiment, requirements such as turbine efficiency can be met, and the design freedom of the housing 20 is increased.

[0096] (2) The primary stationary blade segment in the second method is the same as the primary stationary blade segment 60 in the first method.

[0097] The maximum distance do in the axial direction Da between the rear side surface 65r of the groove and the rear end surface 61r of the outer ring is less than the minimum distance ds in the axial direction Da between the front end surface 57f and the rear end surface 57r of the embedded end ring.

[0098] In this method, compared with the first method, the portion of the outer ring 61 that protrudes downstream of the primary stationary blade 51a towards the axis can be reliably reduced, or the portion of the outer ring 61 that protrudes downstream of the primary stationary blade 51a towards the axis can be eliminated.

[0099] (3) The primary stationary blade segment in the third method is the primary stationary blade segment 60 in the first method or the second method.

[0100] It also includes a caulking component 63, which constrains the relative movement of the plurality of primary stationary blades 51a relative to the outer ring 61.

[0101] The outer ring 61 also has a receiving space forming portion 67. The receiving space forming portion 67, together with the outer shield 55 of the plurality of primary stationary blades 51a, has a surface that forms a receiving space 67s for the caulking member 63 to enter and an opening on the radially inner side Dri. The embedded portion 57 also has an engaging groove 57g, which is recessed from the embedded rear end face 57r towards the upstream side Dau of the axis and extends along the circumferential direction Dc. The outer ring groove 65 also has a protrusion 65c, which protrudes from the groove rear side face 65r towards the upstream side Dau of the axis and extends along the circumferential direction Dc, and is embedded in each of the engaging grooves 57g of the embedded portion 57 of the plurality of primary stationary blades 51a. The receiving space forming portion 67 is connected to the end of the radially inner side Dri of the groove front side face 65f. The caulking member 63 extends along the circumferential direction Dc and falls into the receiving space 67s, and contacts the surface of the receiving space forming part 67, and contacts each of the outer shields 55 in the plurality of primary stationary blades 51a, and is exposed from the opening 68 of the receiving space 67s.

[0102] In this method, the caulking member 63 can be used to constrain the relative movement of the primary stationary blade 51a relative to the outer ring 61.

[0103] (4) The primary stationary blade segment in the fourth method is the primary stationary blade segment 60 in any of the first to third methods.

[0104] The shield body 56 has a shield rear end face 56r, which faces the downstream side Dad of the axis and extends radially outward from the end of the downstream side Dad of the outer gas path surface 56p to the radially outward Dro.

[0105] The outer ring rear end face 61r and the protective cover rear end face 56r are on the same horizontal plane.

[0106] In this method, the portion of the outer ring 61 that protrudes downstream of the primary stationary blade 51a towards the axis can be eliminated.

[0107] The stationary unit in the above embodiments can be understood as follows, for example.

[0108] (5) The stationary unit in the fifth method has the following characteristics:

[0109] The primary stationary blade segment 60 and the blade ring 30a in any of the first to fourth methods are equipped with the primary stationary blade segment 60 and the primary sealing ring 40a.

[0110] The blade ring 30a has: a blade ring gas path surface 32 facing the radially inner side Dri; an outer ring mounting portion 33a on which the outer ring 61 is mounted; and a primary sealing ring mounting portion 36a on which the primary sealing ring 40a is mounted. The primary sealing ring mounting portion 36a is recessed from the blade ring gas path surface 32 toward the radially outer side Dro and extends along the circumferential direction Dc. The outer ring mounting portion 33a is located entirely at a position Dau further upstream on the axis than the primary sealing ring mounting portion 36a.

[0111] In this method, a primary sealing ring 40a can be installed on the blade ring 30a that forms part of the housing 20 to seal the gap between the primary stationary blade 51a and the primary moving blade 13 without expanding the axial distance between them.

[0112] (6) The stationary unit in the sixth embodiment is located in the stationary unit 80 of the fifth embodiment.

[0113] The outer ring mounting portion 33a of the blade ring 30a has a mounting side surface 34 and a mounting inner circumferential surface 35.

[0114] The mounting side 34 extends radially outward from the gas path surface 32 of the blade ring, at a position on the upstream side Dau of the axis, beyond the primary sealing ring mounting portion 36a, and extends along the circumferential direction Dc, opposite the rear end face 61r of the outer ring. The mounting inner circumferential surface 35 extends from the edge of the radially outward Dro of the mounting side 34 toward the upstream side Dau of the axis, and extends along the circumferential direction Dc, opposite the outer circumferential surface 61o of the outer ring.

[0115] In this method, the mounting side 34 of the blade ring 30a can be positioned close to the rear end face 61r of the outer ring.

[0116] (7) The stationary unit in the seventh method is the stationary unit 80 in the fifth or sixth method.

[0117] It also has multiple rows of post-stage stationary blades 50r arranged along the axial direction Da.

[0118] The plurality of subsequent stage stationary blade rows 50r each have a plurality of stationary blades 51 extending along the circumferential direction Dc. The blade ring 30a has a plurality of blade ring grooves 39 extending along the axial direction Da in a region further downstream of the primary sealing ring mounting portion 36a on the axial side Dad. The plurality of blade ring grooves 39 are all recessed from the blade ring gas path surface 32 toward the radially outward direction Dro and extend along the circumferential direction Dc. The plurality of stationary blades 51 constituting any one of the plurality of subsequent stage stationary blade rows 50r are embedded in each of the plurality of blade ring grooves 39.

[0119] The steam turbine in the above embodiments can be understood, for example, as follows.

[0120] (8) The steam turbine in the eighth method has:

[0121] The static unit 80 in any of the fifth to seventh methods; the steam inlet pipe 16; the rotor 10, which is capable of rotating about the axis Ar; and the housing 20, which covers the outer periphery of the rotor 10.

[0122] The housing 20 has the blade ring 30a. The steam inlet pipe 16 is configured such that steam S flows from the upstream side of the axis Dau into the space between the outer peripheral side of the rotor 10 and the inner peripheral side of the housing 20.

[0123] The primary stationary blade segment unit in the above embodiments can be understood as follows.

[0124] (9) The primary stationary blade segment unit in the ninth method has:

[0125] The primary stationary blade segment 60 in any of the first to fourth methods is the first primary stationary blade segment 60f; the second primary stationary blade segment 60s is arranged at a distance from the first primary stationary blade segment 60f on the second side Da2; and the flow splitter 71 extends along the circumferential direction Dc and connects the first primary stationary blade segment 60f and the second primary stationary blade segment 60s.

[0126] The second primary stationary blade segment 60s includes: a second outer ring 61s extending along the circumferential direction Dc and having the same shape as the outer ring 61 of the first primary stationary blade segment 60f, i.e., the first outer ring 61f, with the first side Da1 as the upstream side Dau and the second side Da2 as the downstream side Dad; and a plurality of second primary stationary blades 51as arranged and mounted along the circumferential direction Dc on the radially inner side Dri of the second outer ring 61s, having the same shape as the plurality of primary stationary blades 51a of the first primary stationary blade segment 60f, i.e., the plurality of first primary stationary blades 51af, with the first side Da1 as the upstream side Dau and the second side Da2 as the downstream side Dad. The diversion component 71 includes: a first connecting portion 72f, connected to the inner shroud 53 of each of the plurality of first primary stationary blades 51af; a second connecting portion 72s, connected to the inner shroud 53 of each of the plurality of second primary stationary blades 51as; and a body 73, connecting the first connecting portion 72f and the second connecting portion 72s. The body 73 has gas path surfaces 74f and 74s, which extend radially outward toward the radially outward Dro along the axial direction Da, and are connected to the inner gas path surface 53p of each of the plurality of first primary stationary blades 51af and the inner gas path surface 53p of each of the plurality of second primary stationary blades 51as.

[0127] In this manner, a portion of the steam S flowing from the radially outer side Dro of the diversion component 71 toward the radially inner side Dri can be guided to the first primary stationary blade 51af, and the remaining portion of the steam S can be guided to the second primary stationary blade 51as.

[0128] (10) The primary stationary blade segment unit in the tenth embodiment is the primary stationary blade segment unit 70 in the ninth embodiment.

[0129] The inner shield 53 has: a gas path opposite surface 53q, which faces the radially inner side Dri and has a back-to-back relationship with the inner gas path surface 53p; and a connecting groove 53g, which is recessed from the gas path opposite surface 53q toward the radially outer side Dro and extends along the circumferential direction Dc.

[0130] The first connecting portion 72f has a protrusion 72fc, which is embedded in the connecting groove 53g in the inner shroud 53 of each of the plurality of first primary stationary blades 51af. The second connecting portion 72s has a protrusion 72sc, which is embedded in the connecting groove 53g in the inner shroud 53 of each of the plurality of second primary stationary blades 51as. The connecting groove 53g is formed such that the groove width in the axial direction Da gradually increases as it moves toward the radially outward Dro. The protrusions 72fc and 72sc are formed such that the convex width in the axial direction Da gradually increases as it moves toward the radially outward Dro.

[0131] In this method, even without welding the inner shroud 53 and the flow divider 71 of each of the plurality of first primary stationary blades 51af, the inner shroud 53 and the flow divider 71 of each of the plurality of first primary stationary blades 51af can be securely connected. Furthermore, in this method, even without welding the inner shroud 53 and the flow divider 71 of each of the plurality of second primary stationary blades 51as, the inner shroud 53 and the flow divider 71 of each of the plurality of second primary stationary blades 51as can be securely connected.

[0132] (11) The primary stationary blade segment unit in the eleventh embodiment is in the primary stationary blade segment unit 70 of the ninth or tenth embodiment.

[0133] The diversion component 71 includes a first diversion component 71f, a second diversion component 71s, and a connecting member 76.

[0134] The first diverting component 71f has: a first connecting portion 72f; and a first body 73f, extending from the first connecting portion 72f toward the second side Da2 and forming a portion of the body. The second diverting component 71s has: a second connecting portion 72s; and a second body 73s, extending from the second connecting portion 72s toward the first side Da1 and forming the remaining portion of the body. The connecting member 76 connects the first body 73f and the second body 73s.

[0135] In this configuration, the diversion component 71 is divided into a first diversion component 71f and a second diversion component 71s. Therefore, it is not necessary to perform the operations of inserting the protrusion 72fc of the first connecting portion 72f in the first diversion component 71f into the connecting groove 53g of each of the plurality of first primary stationary blades 51af and the operations of inserting the protrusion 72sc of the second connecting portion 72s in the second diversion component 71s into the connecting groove 53g of each of the plurality of second primary stationary blades 51as in parallel. Therefore, in this configuration, the first connecting portion 72f of the diversion component 71 can be easily connected to the plurality of first primary stationary blades 51af, and the second connecting portion 72s of the diversion component 71 can be easily connected to the plurality of second primary stationary blades 51as.

[0136] The steam turbine in the above embodiments can be understood, for example, as follows.

[0137] (12) The steam turbine in the twelfth method has:

[0138] The following components are included in the ninth to eleventh embodiments: a primary stationary blade segment unit 70; a steam inlet pipe 16; a first rotor 10f, capable of rotating about the axis Ar; a plurality of first subsequent stage stationary blade rows 50rf, arranged along the axial direction Da on the outer periphery of the first rotor 10f; a first housing 20f, covering the outer periphery of the first rotor 10f and mounting the first primary stationary blade segment 60f and the plurality of first subsequent stage stationary blade rows 50rf; a second rotor 10s, capable of rotating about the axis Ar; a plurality of second subsequent stage stationary blade rows 50rs, arranged along the axial direction Da on the outer periphery of the second rotor 10s; and a second housing 20s, covering the outer periphery of the second rotor 10s and mounting the second primary stationary blade segment 60s and the plurality of second subsequent stage stationary blade rows 50rs.

[0139] The first rotor 10f and the second rotor 10s are located on the same axis Ar and are connected to each other. The steam inlet pipe 16 is positioned at a point where it separates from the gas path of the splitter 71 toward the radially outward Dro and connects the first housing 20f and the second housing 20s.

[0140] Industrial availability

[0141] According to one aspect of the present invention, requirements such as turbine efficiency can be met, and the design freedom of the casing can be increased.

[0142] Symbol Explanation

[0143] 10-Rotor, 10f-First rotor, 10s-Second rotor, 11-Rotor shaft, 12-Wheel blade row, 12a-Primary rotor blade row, 12b-Second stage rotor blade row, 12c-Third stage rotor blade row, 12d-Fourth stage rotor blade row, 12e-Fifth stage rotor blade row, 12g-Final stage rotor blade row, 13-Wheel blade, 15-Bearing, 16-Steam inlet pipe, 17-Steam flow path, 20-Shell, 20f-First shell, 20s-Second shell, 21-Inner shell, 22-Exhaust shell, 22s-Exhaust space, 23-Diffuser, 23s-Diffuser space, 24-Downstream end plate, 25-Upstream end plate, 26-Side circumferential plate, 27-Exhaust port, 30-Blade ring, 30a- First blade ring, 30au - First upper blade ring, 30b - Second blade ring, 30c - Third blade ring, 31 - Bolt hole, 32b - Blade ring connecting bolt, 32 - Blade ring gas path surface, 33a - Outer ring mounting part, 33b - Second stage stationary blade row mounting part, 33c - Third stage stationary blade row mounting part, 33d - Fourth stage stationary blade row mounting part, 33e - Fifth stage stationary blade row mounting part, 34 - Mounting side, 35 - Mounting inner circumferential surface, 36a - Primary sealing ring mounting part, 36b - Second stage sealing ring mounting part, 36c - Third stage sealing ring mounting part, 36d - Fourth stage sealing ring mounting part, 36e - Fifth stage sealing ring mounting part, 37 - Base receiving groove, 38 - Foot receiving groove, 39 - Blade ring Groove, 40a - Primary sealing ring, 40b - Secondary sealing ring, 40c - Tertiary sealing ring, 40d - Fourth stage sealing ring, 40e - Fifth stage sealing ring, 41 - Sealing ring base, 42 - Fin, 43 - Base support foot, 50 - Stationary vane row, 50a - Primary stationary vane row, 50af - First primary stationary vane row, 50as - Second primary stationary vane row, 50r - Rear stationary vane row, 50rf - First rear stationary vane row, 50rs - Second rear stationary vane row, 50b - Second stage stationary vane row, 50c - Third stage stationary vane row, 50d - Fourth stage stationary vane row, 50e - Fifth stage stationary vane row, 50f - Sixth stage stationary vane row, 50g - Seventh stage stationary vane row, 51 - Stationary vane, 51a - Primary stationary blade, 51af- First primary stationary blade, 51as- Second primary stationary blade, 52- Blade body, 52f- Leading edge, 52r- Trailing edge, 53- Inner shroud, 53p- Inner gas path surface, 53q- Opposite gas path surface, 53g- Connecting groove, 55- Outer shroud, 56- Shroud body, 56p- Outer gas path surface, 56f- Shroud front end face, 56r- Shroud rear end face, 57- Embedded part, 57f- Embedded front end face, 57r- Embedded rear end face, 57b- Embedded bottom face, 57g- Engaging groove, 60- Primary stationary blade segment, 60f- First primary stationary blade segment, 60s- Second primary stationary blade segment, 61- Outer ring, 61f- First outer ring, 61s- Second outer ring61u - Upper outer ring, 61d - Lower outer ring, 61p - Outer ring gas path surface, 61r - Outer ring rear end face, 61o - Outer ring outer circumferential surface, 62 - Outer ring connecting bolt, 63 - Sealing component, 64 - Fixing nut, 65 - Outer ring groove, 65f - Groove front side, 65r - Groove rear side, 65b - Groove bottom surface, 65c - Protrusion, 67 - Receiving space forming part, 67s - Receiving space, 67b - Space bottom surface, 67r - Space inner surface, 67o - Space bottom opposing surface, 67p - Space side surface, 68 - Opening, 69 - Support plate, 70 - Primary stationary blade segment unit, 71 - Flow splitting component, 71u - Upper half flow splitting component, 71d - Lower half flow splitting component, 71f - First flow splitting component, 71s - Second Diverter component, 72f-first connecting part, 72s-second connecting part, 72fc, 72sc-protrusions, 73-main body, 73f-first main body, 73s-second main body, 74f-first gas path surface, 74s-second gas path surface, 75f-first flange, 75s-second flange, 76-connector, 77-spacer, 80-stationary unit, Ar-axis, Ap-pipe axis, Da-axis direction, Da1-first side, Da2-second side, Dau-upstream side of axis, Dad-downstream side of axis, Dc-circumferential, Dr-radial, Dri-inner radial side, Dro-outer radial side, C-condenser, S-steam, ST1-first steam turbine section, ST2-second steam turbine section.

Claims

1. A primary stationary blade segment, comprising: The outer ring extends circumferentially relative to the axis; and Multiple primary stationary blades are arranged circumferentially on the radially inner side of the outer ring relative to the axis. Of the first and second sides along the axial direction of the extended axis, the second side forms the upstream side of the axis, and the first side forms the downstream side of the axis. The plurality of primary stationary blades each have: a blade body extending radially relative to the axis; an inner shroud formed on the radially inner side of the blade body; and an outer shroud formed on the radially outer side of the blade body relative to the axis. The blade body has: a leading edge forming an edge upstream of the axis; and a trailing edge forming an edge downstream of the axis. The inner shield has an inner gas path surface, which faces radially outward and is connected to the blade body. The outer shield includes: a shield body having an outer gas path surface facing the radially inward side and connected to the blade body; and an embedded portion connected to the radially outer side of the shield body. The embedded part has: an embedded front end face facing upstream of the axis; an embedded rear end face facing downstream of the axis and having a back-to-back relationship with the embedded front end face; and an embedded bottom face facing radially outward and connecting the embedded front end face and the embedded rear end face. The outer ring has an outer ring groove for the outer shroud of each of the plurality of primary stationary blades to enter, an outer ring gas path surface, an outer ring rear end face, and an outer ring outer peripheral surface. The outer groove is recessed from the downstream end of the axis of the outer gas path surface toward the radially outward direction and extends along the circumferential direction. The outer groove has: a front side facing downstream of the axis and opposite to the embedded front end; a rear side facing upstream of the axis and opposite to the embedded rear end; and a bottom surface facing radially inward and opposite to the embedded bottom. The outer gas path surface has a surface that curves gradually from a position upstream of the axis (more so than the front side of the groove) and radially outward (more so than the outer gas path surface) towards the radially inward and downstream of the axis, and connects to the outer gas path surface. The rear end face of the outer ring is located further downstream of the axis than the outer ring groove, and faces downstream of the axis. The outer peripheral surface of the outer ring faces the radially outward side and connects the radially outer edge of the outer ring gas path surface and the radially outer edge of the outer ring rear end face. The embedded front end face is located upstream of the axis than the leading edge. The embedded rear end face is located on the upstream side of the axis, which is closer to the rear edge.

2. The primary stationary blade segment according to claim 1, wherein, The maximum distance in the axial direction between the rear side of the groove and the rear end face of the outer ring is less than the minimum distance in the axial direction between the front end face and the rear end face of the embedded section.

3. The primary stationary blade segment according to claim 1 or 2, further comprising a caulking component, the caulking component constraining the relative movement of the plurality of primary stationary blades relative to the outer ring. The outer ring also has a space-forming section. The accommodating space forming portion and the outer shield of the plurality of primary stationary blades together have a surface that forms an accommodating space for the caulking component to enter and has an opening on the radially inner side. The embedded part also has a locking groove, which is recessed from the rear end of the embedded part towards the upstream side of the axis and extends along the circumferential direction. The outer groove also has a protrusion that protrudes from the rear side of the groove toward the upstream side of the axis and extends circumferentially, and is embedded in each of the engagement grooves of the embedded portion in the plurality of primary stationary blades. The accommodating space forming part is connected to the radially inner end of the front side of the groove. The caulking member extends circumferentially and falls into the receiving space, and contacts the surface of the receiving space forming part that forms the receiving space, and contacts each of the outer shields of the plurality of primary stationary blades, and is exposed from the opening of the receiving space.

4. The primary stationary blade segment according to claim 1 or 2, wherein, The shield body has a rear end face facing downstream of the axis and extending radially outward from the downstream end of the outer gas path surface. The rear end face of the outer ring is at the same horizontal plane as the rear end face of the protective cover.

5. A stationary unit, comprising: The primary stationary blade segment as described in claim 1 or 2; and The blade ring is equipped with the primary stationary blade segment and the primary sealing ring. The blade ring has: a blade ring gas path surface facing the radially inward side; an outer ring mounting portion on which the outer ring is mounted; and a primary sealing ring mounting portion on which the primary sealing ring is mounted. The primary sealing ring mounting portion is recessed from the gas path surface of the blade ring toward the radially outward direction and extends along the circumferential direction. The outer ring mounting portion is located further upstream on the axis than the primary sealing ring mounting portion.

6. The stationary unit according to claim 5, wherein, The outer ring mounting portion of the blade ring has a mounting side surface and a mounting inner circumferential surface. The mounting side extends radially outward from a position on the upstream side of the axis of the blade ring gas path surface, which is further upstream than the primary sealing ring mounting portion, and extends circumferentially, facing the rear end of the outer ring. The mounting inner circumferential surface extends from the radially outer edge of the mounting side towards the upstream side of the axis and extends along the circumferential direction, and faces the outer circumferential surface of the outer ring.

7. The stationary unit according to claim 5, further comprising a plurality of subsequent stationary blade rows arranged along the axial direction. The plurality of subsequent stationary blade rows each have a plurality of stationary blades arranged along the circumferential direction. The blade ring has a plurality of blade ring grooves arranged along the axial direction in a region further downstream of the primary sealing ring mounting portion than the primary sealing ring mounting portion. The plurality of blade annular grooves are all recessed from the blade annular gas path surface toward the radially outer side and extend along the circumferential direction. Each of the plurality of blade annular grooves contains embedded a plurality of stationary blades constituting any one of the plurality of subsequent stationary blade rows.

8. A steam turbine comprising: The stationary unit as described in claim 5; Steam inlet pipe; The rotor is capable of rotating about the said axis; and Housing, covering the outer periphery of the rotor, The housing has the blade ring. The steam inlet pipe is configured such that steam flows from the upstream side of the axis into the space between the outer peripheral side of the rotor and the inner peripheral side of the housing.

9. A primary stationary blade segment unit, comprising: The primary stationary blade segment as described in claim 1 or 2 is the first primary stationary blade segment; The second primary stationary blade segment is arranged at a distance from the first primary stationary blade segment on the second side; and The flow divider extends along the circumferential direction and connects the first primary stationary blade segment and the second primary stationary blade segment. The second primary stationary blade segment has: The second outer ring extends along the circumferential direction and has the same shape as the outer ring of the first primary stationary blade segment, i.e., the first outer ring, with the first side as the upstream side of the axis and the second side as the downstream side of the axis. and Multiple second primary stationary blades are arranged circumferentially on the radially inner side of the second outer ring, and their shape is the same as that of the multiple primary stationary blades of the first primary stationary blade segment, i.e., the multiple first primary stationary blades. The first side is taken as the upstream side of the axis and the second side is taken as the downstream side of the axis. The diversion component includes: a first connecting portion connected to the inner cover of each of the plurality of first primary stationary blades; a second connecting portion connected to the inner cover of each of the plurality of second primary stationary blades; and a main body connecting the first connecting portion and the second connecting portion. The main body has a gas path surface that extends radially outward along the axial direction and is connected to the inner gas path surface of each of the plurality of first primary stationary blades and the inner gas path surface of each of the plurality of second primary stationary blades.

10. The primary stationary blade segment unit according to claim 9, wherein, The inner protective cover has: a gas path opposite surface facing the radially inward side and having a back-to-back relationship with the inner gas path surface; and a connecting groove recessed from the gas path opposite surface to the radially outward side and extending along the circumferential direction. The first connecting portion has a protrusion that is embedded in the connecting groove in the inner shroud of each of the plurality of first primary stationary blades. The second connecting portion has a protrusion that is embedded in the connecting groove in the inner shroud of each of the plurality of second primary stationary blades. The connecting groove is formed such that its width gradually increases in the axial direction as it moves toward the radially outward direction. The protrusion is formed such that its width gradually increases in the axial direction as it moves radially outward.

11. The primary stationary blade segment unit according to claim 9, wherein, The diversion component includes a first diversion component, a second diversion component, and a connecting component. The first diverting component has: a first connecting portion; and a first body extending from the first connecting portion toward the second side and forming a portion of the body. The second diverting component has: a second connecting portion; and a second body extending from the second connecting portion toward the first side and forming the remainder of the body. The connector connects the first body and the second body.

12. A steam turbine comprising: The primary stationary blade segment unit as described in claim 9; Steam inlet pipe; The first rotor is capable of rotating about the axis mentioned above; Multiple rows of first-stage stationary blades are arranged along the axial direction on the outer periphery of the first rotor; A first housing covers the outer periphery of the first rotor and is equipped with the first primary stationary blade segment and the plurality of first subsequent stationary blade rows. The second rotor is capable of rotating about the axis mentioned above; Multiple rows of second-stage stationary blades are arranged along the axial direction on the outer periphery of the second rotor; and The second housing covers the outer periphery of the second rotor and is equipped with the second primary stationary blade segment and the plurality of second subsequent stage stationary blade rows. The first rotor and the second rotor are located on the same axis and are connected to each other. The steam inlet pipe is positioned at a point that separates from the gas path of the splitter component toward the radially outward direction, and connects the first housing and the second housing.

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