Exhaust chamber, steam turbine provided with the exhaust chamber, and method for modifying an exhaust chamber

Abstract

An exhaust chamber includes a diffuser forming a diffuser space, an exhaust casing forming an exhaust space that guides steam flowing from the diffuser space to an exhaust port, a plurality of inner liner members arranged along a circumferential direction across the exhaust space from the diffuser space, and a plurality of support columns respectively provided for the plurality of inner liner members. The exhaust casing has a downstream side end plate that defines an edge of a downstream side of the axis in the exhaust space. The plurality of inner liner members each extend from a position along an inner side diffuser of the diffuser to a position along the downstream side end plate. A first end portion of the support column is engaged with the downstream side end plate. A second end portion of the support column is engaged with the inner liner member.

Description

Technical Field

[0001] This invention relates to an exhaust chamber, a steam turbine having the exhaust chamber, and a method for modifying the exhaust chamber.

[0002] This application claims priority based on Japanese Patent Application No. 2024-064524, filed on April 12, 2024, the contents of which are incorporated herein by reference. Background Technology

[0003] Patent Document 1 discloses a steam turbine with an exhaust chamber. The exhaust chamber serves to guide the steam flowing from the last stage moving blades of the turbine rotor to the outside. The exhaust chamber has a diffuser and an exhaust casing.

[0004] The diffuser forms a diffuser space that is annular relative to the axis of rotation of the rotor, gradually moving radially outward towards the downstream side of the axis. The diffuser has an outer diffuser defining the radially outer edge of the diffuser space and an inner diffuser defining the radially inner edge of the diffuser space. Steam flowing from the last-stage moving blades of the turbine rotor flows into the diffuser space.

[0005] The exhaust casing has an exhaust port that opens radially outward. This exhaust casing communicates with the diffuser space and extends circumferentially relative to the axis, thereby forming an exhaust space that guides steam flowing into the diffuser space to the exhaust port.

[0006] Previous technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2006-329148 Summary of the Invention

[0009] The technical problem to be solved by the invention

[0010] Within the exhaust chamber, pressure recovery of the steam exiting the last-stage moving blades is achieved. The greater this pressure recovery, the lower the pressure of the steam exiting the last-stage moving blades, and the higher the turbine efficiency. Furthermore, in recent years, flexible operation to absorb load variations has been required in thermal power generation equipment. Performing such flexible operation necessitates operating at the design point, i.e., operating at partial load in addition to rated operation. If partial load operation is performed, steam backflow occurs in a portion of the diffuser space and exhaust space, increasing exhaust resistance and reducing pressure recovery.

[0011] Therefore, the object of the present invention is to provide a technique that can suppress the exhaust resistance of steam.

[0012] means for solving technical problems

[0013] An exhaust chamber, one aspect of the invention for achieving the stated purpose, is an exhaust chamber for a steam turbine capable of discharging steam flowing from the last-stage moving blades of a turbine rotor rotating about an axis to the outside. The exhaust chamber comprises: a diffuser forming a diffuser space into which steam flowing from the last-stage moving blades can flow, the diffuser space being annular relative to the axis and gradually expanding radially outward relative to the axis as it moves downstream of the axis; an exhaust casing having an exhaust port opening towards the radially outward direction and communicating with the diffuser space, extending circumferentially relative to the axis to form an exhaust space guiding steam flowing from the diffuser space to the exhaust port; a plurality of liner members disposed across the exhaust space from the diffuser space and arranged circumferentially; and support columns respectively provided for the plurality of liner members.

[0014] The diffuser has an inner diffuser, the cross-section of which is annular relative to the axis and gradually extends radially outward toward the downstream side of the axis, defining the radially inward edge of the diffuser space relative to the axis. The exhaust housing has a downstream end plate defining the downstream edge of the exhaust space relative to the axis. The downstream end plate extends circumferentially in a direction including a radial component relative to the axis. The radially inward edge of the downstream end plate connects to the downstream edge of the inner diffuser. A plurality of liner members extend from a position along the spatial side of the radially inward edge of the diffuser space defined by the inner diffuser, gradually extending radially outward toward the downstream side of the axis, to a position along the spatial side of the exhaust space defined by the downstream end plate. Each of the plurality of liner members has a support post with a first end and a second end. The first end of the support post engages with the inner diffuser or the downstream end plate. The second end of the support column engages with any one of the plurality of liner components. None of the plurality of liner components engage with the inner diffuser or the downstream end plate.

[0015] A steam turbine according to one aspect of the invention for achieving the stated purpose comprises: an exhaust chamber as said aspect; the turbine rotor; and a casing covering the outer periphery of the turbine rotor.

[0016] One aspect of the invention for achieving the stated objective is a method for modifying the exhaust chamber of a steam turbine, which allows steam flowing from the last-stage moving blades of a turbine rotor rotating around an axis to be discharged to the outside. The exhaust chamber comprises: a diffuser forming a diffuser space into which steam flowing from the last-stage moving blades of the turbine rotor rotating around an axis can flow, the diffuser space being annular relative to the axis and gradually expanding radially outward relative to the axis as it moves downstream of the axis; and an exhaust casing having an exhaust port opening towards the radially outward side and communicating with the diffuser space, expanding circumferentially relative to the axis to form an exhaust space that guides steam flowing from the diffuser space to the exhaust port.

[0017] The diffuser has an inner diffuser, the cross-section of which is annular relative to the axis and gradually extends radially outward toward the downstream side of the axis, defining the radially inner edge of the diffuser space relative to the axis. The exhaust housing has a downstream end plate that defines the downstream edge of the exhaust space relative to the axis. The downstream end plate extends circumferentially along a direction including a radial component relative to the axis. The radially inner edge of the downstream end plate connects to the downstream edge of the inner diffuser.

[0018] The method for modifying the exhaust chamber involves the following steps: a preparation step, preparing multiple liner components and their respective support columns; a first joining step, joining the first end of a first end and a second end of the support column to the inner diffuser or the downstream end plate, such that the support columns of the multiple liner components are spaced apart from each other in the circumferential direction; and a second joining step, joining the multiple liner components to the second end of any one of the support columns, such that the multiple liner components are arranged circumferentially, and each of the multiple liner components extends from a position outside the space along the radially inner edge of the diffuser space defined by the inner diffuser, gradually moving towards the downstream side of the axis as it moves towards the radially outer side, to a position along the side of the exhaust space defined by the downstream end plate. In the second joining step, the multiple liner components are not joined to the inner diffuser and the downstream end plate.

[0019] Invention Effects

[0020] According to one aspect of the present invention, steam exhaust resistance can be suppressed. Furthermore, according to one aspect of the present invention, welding deformation of the inner diffuser and downstream end plate can be suppressed. Attached Figure Description

[0021] Figure 1 This is a perspective view of a steam turbine in one embodiment of the present invention.

[0022] Figure 2 It is along Figure 1 A sectional view cut along line II-II.

[0023] Figure 3 It is along Figure 1 A sectional view cut along line III-III.

[0024] Figure 4 It is along Figure 3 A sectional view cut along line IV-IV.

[0025] Figure 5 This is a perspective view of the lining component and the support column, viewed from the reverse side of the lining component in one embodiment of the present invention.

[0026] Figure 6 This is a perspective view of the lining component and the support column as seen from a spatial side view of the lining component in one embodiment of the present invention.

[0027] Figure 7 This is a flowchart illustrating the steps of modifying the exhaust chamber in one embodiment of the present invention.

[0028] Figure 8 This is a perspective view of the lining component and support column after the first joining process and before the second joining process in one embodiment of the present invention.

[0029] Figure 9 This is an explanatory diagram showing the flow of steam in the exhaust chamber before modification in one embodiment of the present invention.

[0030] Figure 10 This is an explanatory diagram showing the flow of steam in a modified exhaust chamber according to one embodiment of the present invention.

[0031] Figure 11 This is a cross-sectional view of the exhaust chamber in the comparative example. Detailed Implementation

[0032] The following is a detailed description of one embodiment of the steam turbine in this invention.

[0033] "Implementation Method"

[0034] refer to Figures 1 to 11 An embodiment of the steam turbine involved in this invention will be described.

[0035] The steam turbine in this embodiment is a dual-flow exhaust type steam turbine. Therefore, as... Figure 1 and Figure 2 As shown, the steam turbine includes a first steam turbine section 10a and a second steam turbine section 10b. Figure 2 As shown, both the first steam turbine section 10a and the second steam turbine section 10b include a turbine rotor 11 rotating around an axis Ar, a housing 20 covering the turbine rotor 11, a plurality of stator vanes 17 fixed to the housing 20, and a steam inlet pipe 19. Furthermore, hereinafter, the circumferential direction centered on the axis Ar will be referred to as the circumferential direction Dc, and the radial direction relative to the axis Ar will be referred to as the radial direction Dr. Moreover, on this radial direction Dr, the side closer to the axis Ar is designated as the radial inner side Dri, and the side opposite to it is designated as the radial outer side Dro.

[0036] The first steam turbine section 10a and the second steam turbine section 10b share a steam inlet pipe 19. In the first steam turbine section 10a, components other than the steam inlet pipe 19 are arranged on one side of the axial direction Da with reference to the steam inlet pipe 19. Similarly, in the second steam turbine section 10b, components other than the steam inlet pipe 19 are arranged on the other side of the axial direction Da with reference to the steam inlet pipe 19. Furthermore, in each steam turbine section 10a and 10b, in the aforementioned axial direction Da, one side of the steam inlet pipe 19 is designated as the upstream side Dau, and the opposite side is designated as the downstream side Dad.

[0037] The structure of the first steam turbine section 10a is basically the same as that of the second steam turbine section 10b. Therefore, the first steam turbine section 10a will be mainly described below.

[0038] The turbine rotor 11 includes: a rotor shaft 12 extending along the axial direction Da with axis Ar as its center; and a plurality of moving blades 13 mounted on the rotor shaft 12. The turbine rotor 11 is supported by a bearing 18 in a manner that enables it to rotate around axis Ar. The plurality of moving blades 13 are arranged along the axial direction Da. Each moving blade 13 is composed of a plurality of moving blades arranged circumferentially Dc. The turbine rotor 11 of the first steam turbine section 10a and the turbine rotor 11 of the second steam turbine section 10b are located on the same axis Ar and connected to each other, and rotate integrally around axis Ar.

[0039] The housing 20 has a body shell 21 and an exhaust chamber 25. The body shell 21 forms a generally conical space with the axis Ar as the center and covers the outer periphery of the turbine rotor 11.

[0040] Multiple moving blades 13 of the turbine rotor 11 are disposed within the conical space. Multiple stationary blades 17 are arranged along the axial direction and disposed within the conical space. The multiple stationary blades 17 are respectively disposed on the upstream side of the axial direction of any one of the multiple moving blades 13. The multiple stationary blades 17 are fixed to the casing 21.

[0041] like Figure 3 As shown, the exhaust chamber 25 has a diffuser 26, an exhaust housing 30, a plurality of liner components 40 and support columns 45 for each of the plurality of liner components 40.

[0042] The diffuser 26 is annular relative to the axis Ar, and forms a diffuser space 26s that gradually extends radially outward toward the downstream side Dad. Steam flowing out from the last-stage vane 13a of the turbine rotor 11 flows into the diffuser space 26s. The last-stage vane 13a is the vane 13 located furthest downstream of the axis Dad among the multiple vane 13s. The diffuser 26 has an outer diffuser (or steam guide, deflector) 27 that defines the edge of the radially outward side Dad of the diffuser space 26s, and an inner diffuser (or bearing cone) 29 that defines the edge of the radially inward side Dri of the diffuser space 26s. The cross-section of the outer diffuser 27 perpendicular to the axis Ar is annular, and gradually extends radially outward toward the downstream side Dad. The cross-section of the inner diffuser 29 perpendicular to the axis Ar is also annular, and also gradually extends radially outward toward the downstream side Dad. The outer diffuser 27 is connected to the body shell 21.

[0043] The exhaust casing 30 has an exhaust port 31. This exhaust port 31 opens radially outward (Dro) and vertically downward. A condenser Co, which converts steam back into water, is connected to this exhaust port 31. Therefore, the steam turbine of this embodiment is a bottom-exhaust type condensing steam turbine. Here, in the orthogonal direction orthogonal to the axis Ar, with the axis Ar as a reference, the side where the exhaust port 31 is located is designated as the exhaust side (Dpe), and the side opposite to the exhaust side (Dpe) is designated as the non-exhaust side (Dpu). Furthermore, as described above, since the steam turbine of this embodiment is a bottom-exhaust type condensing steam turbine, the exhaust side (Dpe) is the vertically lower side, and the non-exhaust side (Dpu) is the vertically upper side.

[0044] The exhaust casing 30 forms an exhaust space 30s communicating with the diffuser 26. This exhaust space 30s extends circumferentially Dc relative to the axis Ar along the outer periphery of the diffuser 26, guiding the steam flowing into the diffuser space 26s to the exhaust port 31. The exhaust casing 30 has a downstream end plate 32, an upstream end plate 34, and an outer peripheral plate 36.

[0045] like Figures 1-3As shown, the downstream end plate 32 defines the edge of the downstream side Dad of the exhaust space 30s. This downstream end plate 32 extends along a direction including the radial Dr component and the circumferential Dc, and is substantially perpendicular to the axis Ar. The portion of the downstream end plate 32 that is higher than the axis Ar is approximately semi-circular. On the other hand, the portion of the downstream end plate 32 that is lower than the axis Ar is approximately rectangular. However, a circular opening centered on the axis Ar is formed on this downstream end plate 32. The edge of this circular opening forms the edge of the radially inner Dri of the downstream end plate 32. The edge of the downstream side Dad of the axis of the inner diffuser is connected to the edge of the radially inner Dri of the downstream end plate 32. The lower edge of this downstream end plate 32 forms part of the edge of the exhaust port 31.

[0046] The outer peripheral plate 36 defines the radially outer edge of the exhaust space 30s (Dro). This outer peripheral plate 36 extends along the axial direction (Da) and along a direction containing a circumferential component (Dc) centered on the axis (Ar). The outer peripheral plate 36 has a semi-cylindrical shape on its upper side. The downstream edge of the outer peripheral plate 36 (Dad) connects to the downstream end plate 32. Furthermore, the lower edge of the outer peripheral plate 36 forms part of the edge of the exhaust port 31.

[0047] The upstream end plate 34 defines the edge of the upstream side Dau of the exhaust space 30s. The upstream end plate 34 is positioned further upstream of the diffuser 26 than the upstream side Dau. The upstream end plate 34 extends radially outward Dro from the outer periphery of the housing 21. The upstream end plate 34 is substantially perpendicular to the axis Ar. Therefore, the upstream end plate 34 is spaced apart from the downstream end plate 32 in the axial direction Da. The lower edge of the upstream end plate 34 forms part of the edge of the exhaust port 31. The portion of the radially outward Dro edge of the upstream end plate 34, excluding the portion forming the edge of the exhaust port 31, is connected to the outer peripheral plate 36.

[0048] The exhaust casing 30 of the first steam turbine section 10a and the exhaust casing 30 of the second steam turbine section 10b are connected to each other to form a single unit.

[0049] like Figure 3 and Figure 4As shown, multiple liner components 40 are disposed only on the non-exhaust side Dpu with reference to the axis Ar, and are arranged circumferentially Dc. The multiple liner components 40 are disposed across the exhaust space 30s from the diffuser space 26s. The multiple liner components 40 extend from a position on the spatial side 29p along the edge of the radially inner side Dri of the diffuser space 26s defined by the inner diffuser 29, gradually moving towards the downstream side Dad along the axis as they move towards the radially outer side Dro, to a position on the spatial side 32p along the exhaust space 30s defined by the downstream end plate 32.

[0050] As described above, the support columns 45 are provided for each of the plurality of liner components 40. Therefore, the number of support columns 45 is the same as the number of the plurality of liner components 40. The support column 45 has a first end 45a and a second end 45b. The second end 45b of the support column 45 is joined to the liner component 40 opposite to the support column 45 by welding. And, the first end 45a of the support column 45 is joined to the downstream end plate 32 by welding.

[0051] like Figure 5 , Figure 6 and Figure 8 As shown, the inner lining component 40 has an inner lining plate 41 and a plurality of reinforcing ribs 43.

[0052] The inner liner 41 has a spatial side 41p and an anti-spatial side 41pa positioned back-to-back, and a circular opening 42. The spatial side 41p faces radially outward (Dro), and the anti-spatial side 41pa faces radially inward (Dri). The edges of both the spatial side 41p and the anti-spatial side 41pa have an arc-shaped or straight outer edge 41o, an arc-shaped or straight inner edge 41i, and a pair of side edges 41s. The inner edge 41i is positioned back-to-back with the outer edge 41o. The length of the inner edge 41i is shorter than the length of the outer edge 41o. The pair of side edges 41s are positioned back-to-back with each other. The lengths of the pair of side edges 41s are the same. The opening 42 extends from the spatial side 41p to the anti-spatial side 41pa, passing through the middle of the pair of side edges 41s of the inner liner 41.

[0053] The plurality of reinforcing ribs 43 include: a first reinforcing rib 43a, disposed on one side of one of a pair of side edges 41s with reference to the position of the opening 42 in the inner liner 41; and a second reinforcing rib 43b, disposed on one side of the other side edge 41s. Both the first reinforcing rib 43a and the second reinforcing rib 43b extend from the outer edge 41o to the inner edge 41i along the anti-space side 41pa of the inner liner 41. The spacing between the first reinforcing rib 43a and the second reinforcing rib 43b gradually widens from the inner edge 41i toward the outer edge 41o.

[0054] A second end 45b of a support post 45 enters through an opening 42 in the inner liner 41, the second end 45b being joined to the edge of the opening 42 by welding.

[0055] Of the multiple liner components 40, the radial dimension Lre of the liner plate 41 located on the exhaust side Dpe on the circumferential Dc is smaller than that of the liner plate 41 located on the non-exhaust side Dpu on the circumferential Dc. Specifically, in this embodiment, the radial dimension Lr of the liner plates 41 arranged along the circumferential Dc gradually decreases as they are located on the exhaust side Dpe on the circumferential Dc.

[0056] Next, according to Figure 7 The flowchart shown illustrates the modification method for exhaust chamber 25.

[0057] Additionally, the modification method here is to install multiple inner lining components 40 and multiple support columns 45 in the exhaust chamber 25a ( Figure 9 The method of setting multiple inner lining components 40 and multiple support columns 45 as shown in the figure.

[0058] First, prepare the multiple inner lining components 40 and multiple support columns 45 as described above (preparation step S1).

[0059] Next, the first end 45a of each support column 45 is welded to the spatial side 32p of the downstream end plate 32 so that the multiple support columns 45 are spaced apart from each other in the circumferential direction Dc (first joining step S2).

[0060] Next, as Figure 8 As shown, the second end 45b of the support column 45, which is fixed to the downstream end plate 32, is inserted into the opening 42 of the liner component 40, and the second end 45b is welded to the liner component 40 (second joining step S3). At this time, the spatial side 41p of the liner plate 41 faces radially outward Dro, and the anti-spatial side 41pa of the liner plate 41 faces radially outward Dro. The outer edge 41o of the liner plate 41 is located radially outward Dro relative to the outer edge 41o of the liner plate 41. The liner plate 41 extends from the position along the spatial side 29p of the inner diffuser 29 towards the downstream side Dad of the axis as it faces radially outward Dro, to the position along the spatial side 32p of the downstream end plate 32. When the second end 45b of the support column 45 is joined to the liner component 40, the liner component 40 is slightly rotated about the central axis of the support column 45, thereby adjusting the angle of the liner component 40 about the central axis of the support column 45. After the adjustment is completed, the edge of the opening 42 of the liner component 40 is joined to the support column 45 by welding.

[0061] The modification of exhaust chamber 25a is now complete.

[0062] At the time the modification of exhaust chamber 25a was completed, several liner components 40 were not connected to the inner diffuser 29 and the downstream end plate 32. That is, as Figure 3 As shown, the outer edge 41o of the inner liner 41 is not connected to the spatial side 32p of the downstream end plate 32, and a gap c exists between the inner liner 41 and the spatial side 32p of the downstream end plate 32. Furthermore, the inner edge 41i of the inner liner 41 is not connected to the spatial side 29p of the inner diffuser 29, and a gap c exists between the inner liner 41 and the spatial side 29p of the inner diffuser 29. Moreover, as... Figure 4 As shown, the lining components 40 that are adjacent to each other on the circumferential direction Dc are not joined to each other, and there is also a gap c between the lining components 40 that are adjacent to each other on the circumferential direction Dc.

[0063] As described above, in the modification method of this embodiment, firstly, after the support column 45 is joined to the downstream end plate 32, the inner liner component 40 is installed from the radially outer side (Dro) towards the radially inner side (Dri) within the diffuser space 26s and the exhaust space 30s. Therefore, the inner liner component 40 can be easily joined to the support column 45. Furthermore, in this embodiment, the support column 45 is cylindrical, and the opening 42 of the inner liner component 40 is circular, thus allowing the inner liner component 40 to be slightly rotated around the central axis of the support column 45, thereby adjusting the angle of the inner liner component 40 around the central axis of the support column 45.

[0064] Next, the effects of the modified exhaust chamber 25 will be explained.

[0065] like Figure 9 As shown, in the exhaust chamber 25a before modification, steam flowing from the last stage moving blade 13a of the turbine rotor 11 to the downstream side Dad of the axis flows into the diffuser space 26s. During the diffuser space 26s, the steam flows towards the downstream side Dad of the axis while simultaneously flowing towards the radially outward Dro, and then flows into the exhaust space 30s.

[0066] With axis Ar as the reference, in the region of non-exhaust side Dpu, the steam flowing into exhaust space 30s along the spatial side 27p of the outer diffuser 27 extends tangentially to the radially outer end of the spatial side 27p, i.e., in the tangential direction. If the steam collides with the outer peripheral plate 36, part of it flows along the outer peripheral plate 36 upstream of the axis, Dau, and the other part flows along the outer peripheral plate 36 circumferentially, Dc, i.e., exhaust side Dpe.

[0067] The steam flowing upstream along the outer peripheral plate 36 gradually changes its flow direction to circumferential Dc, and flows along the inner circumference of the outer peripheral plate 36 to the exhaust side Dpe. The steam flowing along the outer peripheral plate 36 to the exhaust side Dpe is discharged from the exhaust port 31.

[0068] Furthermore, with axis Ar as the reference, in the region outside the exhaust side Dpu, the steam flowing into the exhaust space 30s along the spatial side 29p of the inner diffuser 29 collides with the downstream end plate 32, and a portion flows radially outward along the downstream end plate 32 to Dro. The steam flowing radially outward to Dro collides with the outer peripheral plate 36 and flows circumferentially along the outer peripheral plate 36 to Dc, i.e., the exhaust side Dpe. This steam is discharged from the exhaust port 31.

[0069] The remaining steam, which flows along the spatial side 29p of the inner diffuser 29 and collides with the downstream end plate 32, flows radially inward along the downstream end plate 32, and then flows upstream along the axis towards ...

[0070] That is, in the region where the diffuser space 26s and the exhaust space 30s meet, and along the inner diffuser 29 and the downstream end plate 32, a backflow of steam occurs. If a backflow of steam occurs, the exhaust resistance of the steam increases and the pressure recovery decreases.

[0071] On the other hand, with axis Ar as a reference, in the region of exhaust side Dpe, the flow direction of steam flowing into exhaust space 30s along the spatial side 27p of the outer diffuser 27 is defined as the tangential direction extending from the tangent of the radially outer end of the spatial side 27p (i.e., the direction component near the exhaust port 31), relative to axis Ar in the circumferential direction Dc, the direction component near the exhaust port 31. This is because steam from the region of non-exhaust side Dpu within exhaust chamber 25, containing a larger circumferential Dc component, flows into the region of exhaust side Dpe. As described above, since the flow direction component of steam flowing into exhaust space 30s along the spatial side 27p of the outer diffuser 27 includes a component near the exhaust port 31, the steam flowing into exhaust space 30s along the spatial side 27p of the outer diffuser 27 does not flow backwards but is discharged from exhaust port 31.

[0072] Furthermore, with axis Ar as the reference, in the region of exhaust side Dpe, the steam flowing into exhaust space 30s along the spatial side 29p of the inner diffuser 29 collides with the downstream end plate 32 and flows radially outward towards exhaust port 31. This is because the directional component of the steam flowing along the spatial side 29p of the inner diffuser 29 includes the directional component of the exhaust port 31. As a result, the steam flowing into exhaust space 30s along the spatial side 29p of the inner diffuser 29 does not flow backwards but is discharged from exhaust port 31.

[0073] Under low-load operation conditions with low steam flow into the steam turbine or low vacuum conditions in the condenser Co, the circumferential Dc component (rotational component) centered on the axis Ar becomes relatively larger in the directional component of the steam flowing out of the last-stage moving vane 13a of the turbine rotor 11 compared to the directional component towards the downstream side Dad. Therefore, in this case, the tendency of the steam flowing out of the last-stage moving vane 13a of the turbine rotor 11 to deflect radially outward (Dro) within the diffuser space 26s increases. Consequently, the steam flow rate on the outer diffuser 27 side becomes greater than the steam flow rate on the inner diffuser 29 side within the diffuser space 26s. That is, under low-load operation conditions or low vacuum conditions in the condenser Co, the steam flow along the inner circumferential surface of the outer diffuser 27 increases. Therefore, in the original exhaust chamber 25, with the axis Ar as the reference, in the non-exhaust side Dpu, under low load operation or low vacuum in the condenser Co, the amount of steam backflow in this area becomes more, the exhaust resistance of steam increases, and the pressure recovery decreases.

[0074] Furthermore, in the region closer to the non-exhaust side Dpu than the axis Ar, the area of ​​steam backflow gradually decreases as it approaches the exhaust side Dpe on the circumferential Dc. This is because, as it approaches the exhaust side Dpe on the circumferential Dc, the directional component of the steam flowing into the exhaust space 30s along the side 29p of the inner diffuser 29 gradually increases towards the exhaust port 31. Moreover, this is because, within the exhaust space 30s, steam containing a larger circumferential Dc component flows from the region of the non-exhaust side Dpu on the circumferential Dc.

[0075] like Figure 10 As shown, in the modified exhaust chamber 25, similarly to the original exhaust chamber 25a, the steam flowing from the last stage moving blade 13a of the turbine rotor 11 to the downstream side Dad of the axis also flows into the diffuser space 26s. This steam flows towards the downstream side Dad of the axis and towards the radially outward Dro in the diffuser space 26s, and flows into the exhaust space 30s.

[0076] With axis Ar as the reference, in the region of non-exhaust side Dpu, similarly to the original exhaust chamber 25a, the steam flowing into the exhaust space 30s along the spatial side 27p of the outer diffuser 27 extends tangentially to the end of the radially outer Dro of the spatial side 27p. If the steam collides with the outer peripheral plate 36, part of it flows along the outer peripheral plate 36 upstream of the axis Dau, and the other part flows along the outer peripheral plate 36 circumferentially Dc, i.e., the exhaust side Dpe.

[0077] The steam flowing upstream along the outer peripheral plate 36 gradually changes its flow direction to circumferential Dc, and flows along the inner peripheral surface of the outer diffuser 27 to the exhaust side Dpe. The steam flowing along the outer peripheral plate 36 to the exhaust side Dpe is discharged from the exhaust port 31.

[0078] Furthermore, with axis Ar as the reference, in the region of non-exhaust side Dpu, steam flows along the spatial side 29p of the inner diffuser 29, then along the spatial side 41p of the liner component 40, and collides with the downstream end plate 32. The steam colliding with the downstream end plate 32 flows substantially entirely along the downstream end plate 32 radially outward Dro. The steam flowing radially outward Dro collides with the outer peripheral plate 36 and flows along the outer peripheral plate 36 circumferentially Dc, i.e., the exhaust side Dpe. The steam flowing along the outer peripheral plate 36 towards the exhaust side Dpe is discharged from the exhaust port 31.

[0079] As described above, in the modified exhaust chamber 25, with the axis Ar as the reference, the steam flowing along the spatial side 29p of the inner diffuser 29 in the non-exhaust side Dpu is substantially non-reverse.

[0080] This is mainly due to the following reasons.

[0081] (1) The space side 41p of the liner 40 is located further radially outward than the inner diffuser 29, and the flow rate of steam flowing along the liner 40 is greater than the flow rate of steam flowing along the inner diffuser 29.

[0082] (2) The space side 41p of the inner liner 40 is located further radially outward than the inner diffuser 29, and will not form a bag-like portion like the corner of the inner diffuser 29 and the downstream end plate 32, as in the exhaust chamber 25a before the modification.

[0083] (3) The angle between the spatial side 41p of the inner liner 40 and the spatial side 32p of the downstream end plate 32 is larger than the angle between the spatial side 29p of the inner diffuser 29 and the spatial side 32p of the downstream end plate 32, and the collision angle of the steam flowing along the inner liner 40 relative to the downstream end plate 32 becomes shallower.

[0084] On the other hand, with axis Ar as the reference, in the area of ​​exhaust side Dpe, similar to the exhaust chamber 25a before the modification, the steam flowing into the exhaust space 30s along the space side 27p of the outer diffuser 27 will not flow backward, but will be discharged from the exhaust port 31.

[0085] Furthermore, with axis Ar as the reference, in the region of exhaust side Dpe, similar to the exhaust chamber 25a before the modification, the steam flowing into the exhaust space 30s along the space side 29p of the inner diffuser 29 will not flow backward, but will be discharged from the exhaust port 31.

[0086] As described above, in the modified exhaust chamber 25 of this embodiment, the backflow of steam generated in the diffuser space 26s and the exhaust space 30s can be suppressed, thereby suppressing the exhaust resistance of steam.

[0087] Furthermore, in this embodiment, as described above, among the inner liner plates 41 of each of the plurality of inner liner components 40, the radial dimension Lre of the inner liner plate 41 located on the exhaust side Dpe on the circumferential Dc is smaller than the radial dimension Lru of the inner liner plate 41 located on the non-exhaust side Dpu on the circumferential Dc. This is because, as described above, in the region closer to the non-exhaust side Dpu than the axis Ar, the area of ​​steam backflow gradually decreases as it approaches the exhaust side Dpe on the circumferential Dc. Therefore, in this embodiment, it is possible to reduce the amount of plate material used to manufacture the inner liner components 40.

[0088] Furthermore, regarding the effect of the modified exhaust chamber 25 in this embodiment, and as a Figure 10 The exhaust chamber 25b of the comparative example shown will be used for comparison in the explanation.

[0089] The exhaust chamber 25b of this comparative example, like the modified exhaust chamber 25 in this embodiment, has multiple liner components 40. These multiple liner components 40, like those in the modified exhaust chamber 25 in this embodiment, are arranged across the exhaust space 30s from the diffuser space 26s and are arranged circumferentially Dc. Each of the multiple liner components 40 extends from the spatial side 29p of the inner diffuser 29 towards the downstream side Dad along the radially outward direction Dro, to the spatial side 32p of the downstream end plate 32. The multiple liner components 40 are connected to the inner diffuser 29 by welding. Furthermore, the multiple liner components 40 are connected to the downstream end plate 32 by welding. Moreover, the multiple liner components 40 are also connected to each other by welding.

[0090] In this comparative example, during the welding of multiple liner components 40 to the inner diffuser 29, welding deformation occurs in the inner diffuser 29. Furthermore, during the welding of the multiple liner components 40 to the downstream end plate 32, welding deformation occurs in the downstream end plate 32. If welding deformation occurs in the inner diffuser 29 or the downstream end plate 32, the weldability of the subsequently welded liner components 40 decreases. Moreover, if the inner diffuser 29 or the downstream end plate 32 deforms, steam flow becomes turbulent in the deformed portion, increasing the steam exhaust resistance.

[0091] Furthermore, in this comparative example, since the multiple liner components 40 are connected to each other by welding, thermal stress is generated in the multiple liner components 40 due to the difference in thermal expansion between when the steam in the multiple liner components 40 flows in the exhaust chamber 25 and when the steam does not flow in the exhaust chamber 25, thus increasing the possibility of damage to the multiple liner components 40.

[0092] On the other hand, in the modified exhaust chamber 25 of this embodiment, when an inner liner component 40 is fixed inside the exhaust chamber 25, a welded portion is only formed on the downstream end plate 32, and the area of ​​the welded portion is much smaller than that in the comparative example. Therefore, the occurrence of welding deformation of the downstream end plate 32 can be suppressed. Furthermore, in the modified exhaust chamber 25 of this embodiment, when an inner liner component 40 is fixed inside the exhaust chamber 25, no welded portion is formed in the inner diffuser 29, and therefore no welding deformation occurs in the inner diffuser 29. Therefore, in the modified exhaust chamber 25 of this embodiment, the weldability of the inner liner component 40 is improved compared to the comparative example. Moreover, since the deformation of the inner diffuser 29 or the downstream end plate 32 is suppressed, the increase in steam exhaust resistance can be suppressed.

[0093] Furthermore, in this embodiment, the plurality of inner liner components 40 do not contact the inner diffuser 29, and there is a gap c between them. Therefore, in this embodiment, even if the inner liner components 40 thermally expand, the stress generated in the inner liner components 40 and the inner diffuser 29 caused by such thermal expansion can be suppressed.

[0094] Furthermore, in this embodiment, the plurality of inner lining components 40 do not contact the downstream end plate 32, and there is a gap c between them. Therefore, in this embodiment, even if the inner lining components 40 thermally expand, the stress generated in the inner lining components 40 and the downstream end plate 32 caused by such thermal expansion can be suppressed.

[0095] Furthermore, in this embodiment, the multiple inner lining components 40 are not connected to each other by welding, and there is a gap c between them. Therefore, even if the multiple inner lining components 40 are thermally stretched, the stress generated in the inner lining components 40 caused by the thermal stretching can be suppressed.

[0096] "Variations"

[0097] In the exhaust chamber 25 of the above embodiment, the liner member 40 is not provided at a position closer to the exhaust side Dpe than the axis Ar. However, the liner member 40 may be provided at a position closer to the exhaust side Dpe than the axis Ar. However, since the effect of the liner member 40 is small at a position closer to the exhaust side Dpe than the axis Ar, it is preferable to determine whether to provide the liner member 40 at a position closer to the exhaust side Dpe than the axis Ar, considering cost-effectiveness.

[0098] In the above embodiment, among the plurality of inner liner plates 41, the radial dimension Lre of the inner liner plate 41 located on the exhaust side Dpe in the circumferential direction Dc is smaller than the radial dimension Lru of the inner liner plate 41 located on the non-exhaust side Dpu in the circumferential direction Dc. However, it is also possible to make the radial dimensions of all inner liner plates 41 the same as each other.

[0099] In the above embodiment, the first end 45a of the support column 45 is welded to the downstream end plate 32. However, the first end 45a of the support column 45 may also be connected to the inner diffuser 29. However, since the spatial side 29p of the inner diffuser 29 is curved, from the viewpoint of welding construction, it is preferable to weld it to the flat spatial side 32p of the downstream end plate 32.

[0100] This invention is not limited to the embodiments described above. Various additions, modifications, substitutions, partial deletions, etc., can be made without departing from the scope of the patent claims and the conceptual ideas and spirit of the invention derived from their equivalents.

[0101] Postscript

[0102] The exhaust chamber 25 in the above embodiments can be understood, for example, as follows.

[0103] (1) The exhaust chamber 25 in the first embodiment is an exhaust chamber 25 of a steam turbine that can exhaust steam flowing out from the last stage moving blade 13a of the turbine rotor 11 rotating around the axis Ar to the outside. The exhaust chamber 25 includes: a diffuser 26 forming a diffuser space 26s, which allows steam flowing out from the last stage moving blade 13a to flow into, and is annular relative to the axis Ar, and gradually moves radially outward relative to the axis Ar as it moves towards the downstream side Dad of the axis Ar. Extended; an exhaust housing 30 having an exhaust port 31 opening toward the radially outward Dro and communicating with the diffuser space 26s, extending in a circumferential direction Dc relative to the axis Ar, thereby forming an exhaust space 30s that guides steam flowing into the diffuser space 26s to the exhaust port 31; a plurality of liner members 40 configured across the exhaust space 30s from the diffuser space 26s and arranged in a circumferential direction Dc; and support columns 45, each provided for the plurality of liner members 40.

[0104] The diffuser 26 has an inner diffuser 29, the cross-section of which is annular relative to the axis Ar, gradually extending towards the radially outer side Dro as it moves towards the downstream side Dad of the axis, and defining the edge of the diffuser space 26s relative to the radially inner side Dri of the axis Ar. The exhaust housing 30 has a downstream end plate 32, which defines the edge of the downstream side Dad of the axis in the exhaust space 30s. The downstream end plate 32 extends along a direction including a radial Dr component relative to the axis Ar and the circumferential Dc. The edge of the radially inner side Dri of the downstream end plate 32 connects to the edge of the downstream side Dad of the axis of the inner diffuser 29. The plurality of liner components 40 extend from a position on a spatial side 29p along the edge of the radially inner side Dri that defines the diffuser space 26s by the inner diffuser 29, gradually moving towards the downstream side Dad along the radially outer side Dro, to a position on a spatial side 32p along the exhaust space 30s defined by the downstream end plate 32. Each of the plurality of liner components 40 has a support post 45 having a first end 45a and a second end 45b. The first end 45a of the support post 45 engages with either the inner diffuser 29 or the downstream end plate 32. The second end 45b of the support post 45 engages with any one of the plurality of liner components 40. None of the plurality of liner components 40 engages with either the inner diffuser 29 or the downstream end plate 32.

[0105] First, Comparative Example 1 for this embodiment will be described. The exhaust chamber 25a in Comparative Example 1 is an exhaust chamber that omits the multiple liner components 40 and the support columns 45 of each of the multiple liner components 40 from the exhaust chamber 25 of this embodiment.

[0106] In this Comparative Example 1, steam flowing from the last stage moving blade 13a of the turbine rotor 11 toward the downstream side Dad of the axis flows into the diffuser space within 26s. Within the diffuser space within 26s, the steam flows toward the downstream side Dad of the axis while simultaneously flowing toward the radially outward Dro, and flows into the exhaust space within 30s.

[0107] Steam flowing into the exhaust space 30s along the space side 29p of the inner diffuser 29 collides with the downstream end plate 32, and a portion of it flows radially outward along the downstream end plate 32.

[0108] Steam flowing radially outward (Dro) collides with the outer peripheral plate 36 and flows circumferentially (Dc), i.e., the exhaust side (Dpe), along the outer peripheral plate 36. Steam flowing along the outer peripheral plate 36 to the exhaust side (Dpe) is discharged from the exhaust port 31.

[0109] The remaining steam, which flows along the spatial side 29p of the inner diffuser 29 and collides with the downstream end plate 32, flows radially inward along the downstream end plate 32 as appropriate, and then flows upstream along the axial side 29p of the inner diffuser 29 to the axial side 30. This steam merges with the steam flowing from the last stage moving blade 13a of the turbine rotor 11 to the downstream axial side 30, and flows radially outward to the axial side 30 within the diffuser space 26s, simultaneously towards the downstream axial side 30 and the axial side 30.

[0110] That is, in Comparative Example 1, in the region at the junction of diffuser space 26s and exhaust space 30s and along the inner diffuser 29 and downstream end plate 32, steam backflow sometimes occurs. If steam backflow occurs, the exhaust resistance of steam increases and the pressure recovery decreases.

[0111] Similar to the exhaust chamber 25 in Comparative Example 1, in the exhaust chamber 25 of this embodiment, the steam flowing from the last stage moving blade 13a of the turbine rotor 11 to the downstream side Dad of the axis also flows into the diffuser space 26s. This steam flows towards the downstream side Dad of the axis and towards the radially outward Dro in the diffuser space 26s, and flows into the exhaust space 30s.

[0112] In this configuration, steam flows along the spatial side 29p of the inner diffuser 29, then along the spatial side 41p of the liner 40, and collides with the downstream end plate 32. The steam colliding with the downstream end plate 32 flows substantially entirely along the downstream end plate 32 radially outward (Dro). The steam flowing radially outward (Dro) collides with the outer peripheral plate 36 and flows along the outer peripheral plate 36 circumferentially (Dc), i.e., the exhaust side (Dpe). The steam flowing along the outer peripheral plate 36 towards the exhaust side (Dpe) is discharged from the exhaust port 31.

[0113] In this configuration, the steam flowing along the spatial side 29p of the inner diffuser 29 is substantially non-reverse. This is primarily due to the following reasons.

[0114] (1) The space side 41p of the liner 40 is located further radially outward than the inner diffuser 29, and the flow rate of steam flowing along the liner 40 is greater than the flow rate of steam flowing along the inner diffuser 29.

[0115] (2) The space side 41p of the inner liner 40 is located further radially outward than the inner diffuser 29, and will not form a bag-like portion like the corner of the inner diffuser 29 and the downstream end plate 32, as in the exhaust chamber 25a before the modification.

[0116] (3) The angle between the spatial side 41p of the inner liner 40 and the spatial side 32p of the downstream end plate 32 is larger than the angle between the spatial side 29p of the inner diffuser 29 and the spatial side 32p of the downstream end plate 32, and the collision angle of the steam flowing along the inner liner 40 relative to the downstream end plate 32 becomes shallower.

[0117] As described above, in this method, the generation of steam backflow can be suppressed, thereby suppressing the steam exhaust resistance.

[0118] Next, Comparative Example 2 for this embodiment will be described. Similar to the exhaust chamber 25 in this embodiment, the exhaust chamber 25b in Comparative Example 2 has a plurality of liner members 40. Also similar to the exhaust chamber 25 in this embodiment, the plurality of liner members 40 are arranged across the exhaust space 30s from the diffuser space 26s and are arranged circumferentially Dc. The plurality of liner members 40 extend from the spatial side 29p of the inner diffuser 29 towards the downstream side Dad of the axis, gradually moving towards the radially outward side Dro. The plurality of liner members 40 are connected to the inner diffuser 29 by welding. Furthermore, the plurality of liner members 40 are connected to the downstream side end plate 32 by welding. Moreover, the plurality of liner members 40 are also connected to each other by welding.

[0119] In Comparative Example 2, during the welding of multiple liner components 40 to the inner diffuser 29, welding deformation occurred in the inner diffuser 29. Furthermore, during the welding of the multiple liner components 40 to the downstream end plate 32, welding deformation occurred in the downstream end plate 32. If welding deformation occurs in the inner diffuser 29 or the downstream end plate 32, the weldability of the subsequently welded liner components 40 decreases. Moreover, if the inner diffuser 29 or the downstream end plate 32 deforms, steam flow becomes turbulent in the deformed portion, increasing the steam exhaust resistance.

[0120] On the other hand, in the exhaust chamber 25 of this embodiment, when fixing an inner liner component 40, the welding area is only generated in the downstream end plate 32 or the inner diffuser 29, and the area of ​​the welding area is much smaller than that in Comparative Example 2. Therefore, the occurrence of welding deformation of the downstream end plate 32 and the inner diffuser 29 can be suppressed. Therefore, in the exhaust chamber 25 of this embodiment, the weldability of the inner liner component 40 is improved compared with Comparative Example 2. Moreover, since the deformation of the inner diffuser 29 or the downstream end plate 32 is suppressed, the increase in steam exhaust resistance can be suppressed.

[0121] (2) Regarding the exhaust chamber 25 in the second method, In the exhaust chamber 25 of the first embodiment, the plurality of liner components 40 do not contact the inner diffuser 29.

[0122] In this method, even if the inner liner 40 thermally expands, the stress generated by the thermal expansion in the inner liner 40 and the inner diffuser 29 can be suppressed.

[0123] (3) Regarding the exhaust chamber 25 in the third method, In the exhaust chamber 25 of either the first or second method, the plurality of liner components 40 do not contact the downstream end plate 32.

[0124] In this method, even if the inner liner 40 thermally expands, the stress generated by the thermal expansion in the inner liner 40 and the downstream end plate 32 can be suppressed.

[0125] (4) Regarding the exhaust chamber 25 in the fourth method, In the exhaust chamber 25 of any of the first to the third methods, the plurality of liner components 40 do not contact each other.

[0126] In this method, even if multiple inner lining components 40 are thermally stretched, the stress generated in the inner lining components 40 caused by the thermal stretching can be suppressed.

[0127] (5) Regarding the exhaust chamber 25 in the fifth method, In the exhaust chamber 25 of any of the first to fourth methods, the plurality of liner components 40 are arranged with reference to the axis Ar on at least the non-exhaust side Dpu of the exhaust side Dpe where the exhaust port 31 is located and the non-exhaust side Dpu on the side opposite to the exhaust side Dpe.

[0128] As described in Comparative Example 1 above, backflow of steam is easily generated on the non-exhaust side Dpu with respect to the axis Ar. Therefore, by arranging at least a plurality of liner components 40 on the non-exhaust side Dpu, backflow of steam generated throughout the entire exhaust chamber 25 can be effectively suppressed.

[0129] (6) Regarding the exhaust chamber 25 in the sixth method, In the exhaust chamber 25 of any of the first to fourth methods, the plurality of liner components 40 are configured only on the non-exhaust side Dpu, with the axis Ar as a reference, on the exhaust side Dpe where the exhaust port 31 is located and on the non-exhaust side Dpu on the side opposite to the exhaust side Dpe.

[0130] As described in Comparative Example 1 above, steam backflow is easily generated on the non-exhaust side Dpu with respect to the axis Ar. Therefore, by configuring multiple liner components 40 only on the non-exhaust side Dpu, it is possible to suppress steam backflow generated throughout the entire exhaust chamber 25. Moreover, by configuring them only on the non-exhaust side Dpu, it is possible to reduce the material cost and installation cost of the liner components 40.

[0131] (7) Regarding the exhaust chamber 25 in the seventh method, In the exhaust chamber 25 of any of the first to sixth methods, among the plurality of liner members 40 arranged along the circumferential direction Dc, the radial Dr length of the liner member 40 located on the non-exhaust side Dpu opposite to the exhaust side Dpe where the exhaust port 31 is located is longer than the radial Dr length of the liner member 40 located on the exhaust side Dpe compared to the liner member 40 located on the non-exhaust side Dpu.

[0132] In the aforementioned Comparative Example 1, the area of ​​steam backflow gradually decreases as it approaches the exhaust side Dpe on the circumferential Dc. Therefore, in this method, steam backflow can be suppressed and the amount of material used to manufacture the liner component 40 can be reduced.

[0133] (8) Regarding the exhaust chamber 25 in the eighth method, In the exhaust chamber 25 of any of the first to seventh embodiments, the support column 45 is cylindrical. Each of the plurality of liner components 40 has a liner plate 41 that extends from a position along the spatial side 29p of the inner diffuser 29 towards the radially outward Dro towards the downstream side Dad, to a position along the spatial side 32p of the downstream end plate 32. A circular opening 42 is formed in the liner plate 41. The second end 45b of the support column 45 enters the opening 42 of the liner plate 41 and engages with the edge of the opening 42.

[0134] In this method, when the second end 45b of the support column 45 is engaged with the liner member 40, the liner member 40 is slightly rotated about the central axis of the support column 45, thereby making it easy to adjust the angle of the liner member 40 about the central axis of the support column 45.

[0135] (9) Regarding the exhaust chamber 25 in the ninth method, In the exhaust chamber 25 of any of the first to the seventh embodiments, each of the plurality of liner components 40 has: a liner plate 41 extending from a position along the spatial side 29p of the inner diffuser 29 toward the downstream side Dad of the axis as it gradually moves toward the radially outer Dro; and to a position along the spatial side 32p of the downstream end plate 32; and one or more reinforcing ribs 43 engaging with the anti-spatial side 41pa of the liner plate 41 toward the radially inner Dri.

[0136] In this method, deformation of the inner liner component 40 can be suppressed.

[0137] (10) Regarding the exhaust chamber 25 in the tenth method, In the exhaust chamber 25 of the ninth embodiment, one or more reinforcing ribs 43 have: a first reinforcing rib 43a, disposed on one side of the circumferential direction Dc, with reference to the engagement position with the support column 45 in the inner liner 41; and a second reinforcing rib 43b, disposed on the other side of the circumferential direction Dc. Both the first reinforcing rib 43a and the second reinforcing rib 43b extend along the anti-space side 41pa in a manner that gradually moves towards the downstream side Dad of the axis as it moves towards the radially outward Dro.

[0138] (11) Regarding the exhaust chamber 25 in the eleventh method, In the exhaust chamber 25 of the tenth embodiment, the circumferential spacing Dc between the first reinforcing rib 43a and the second reinforcing rib 43b gradually widens toward the downstream side Dad of the axis.

[0139] The steam turbine in the above embodiments can be understood, for example, as follows.

[0140] (12) The steam turbine in the twelfth method has: The exhaust chamber 25 in any of the first to eleventh methods; the turbine rotor 11; and the shell 21, covering the outer periphery of the turbine rotor 11.

[0141] The steam turbine in this embodiment has the exhaust chamber 25 as in the first embodiment, thus suppressing the generation of steam backflow and thereby suppressing steam exhaust resistance. Furthermore, the steam turbine in this embodiment can suppress the generation of welding deformation of the downstream end plate 32 and the inner diffuser 29.

[0142] The method for modifying the exhaust chamber in the above embodiments can be understood as follows.

[0143] (13) The method for modifying the exhaust chamber in the thirteenth method is a method for modifying the exhaust chamber 25a of a steam turbine, which can guide the steam flowing out of the last stage moving blade 13a of the turbine rotor 11 rotating around the axis Ar to the outside. The exhaust chamber 25a includes: a diffuser 26 forming a diffuser space 26s, which allows the steam flowing out of the last stage moving blade 13a of the turbine rotor 11 rotating around the axis Ar to flow in, and is annular relative to the axis Ar, and gradually expands towards the radially outer side Dro relative to the axis Ar as it moves towards the downstream side Dad of the axis; and an exhaust casing 30 having an exhaust port 31 opening towards the radially outer side Dro and communicating with the diffuser space 26s, and expanding along the circumferential direction Dc relative to the axis Ar, thereby forming an exhaust space 30s that guides the steam flowing in from the diffuser space 26s to the exhaust port 31.

[0144] The diffuser 26 has an inner diffuser 29, the cross-section of which is annular relative to the axis Ar, gradually extending towards the radially outer side Dro as it moves towards the downstream side Dad of the axis, and defining the edge of the diffuser space 26s relative to the radially inner side Dri of the axis Ar. The exhaust housing 30 has a downstream end plate 32, which defines the edge of the downstream side Dad of the axis in the exhaust space 30s. The downstream end plate 32 extends along a direction including a radial Dr component relative to the axis Ar and the circumferential Dc. The edge of the radially inner side Dri of the downstream end plate 32 connects to the edge of the downstream side Dad of the axis of the inner diffuser 29.

[0145] The modification method for the exhaust chamber 25a includes the following steps: a preparation step S1, preparing a plurality of inner liner components 40 and support columns 45 for each of the plurality of inner liner components 40; a first joining step S2, joining the first end 45a of the first end 45a and the second end 45b of the support column 45 to the inner diffuser 29 or the downstream end plate 32, such that the support columns 45 of each of the plurality of inner liner components 40 are spaced apart from each other on the circumferential direction Dc; and a second joining step S3, connecting the plurality of inner liner components... The member 40 is respectively engaged with the second end 45b of any one of the support columns 45, such that the plurality of liner members 40 are arranged along the circumferential direction Dc, and the plurality of liner members 40 extend from a position outside the space outside the edge of the radially inner side Dri defined by the inner diffuser 29, gradually moving towards the downstream side Dad of the axis as they move towards the radially outer side Dro, to a position along the space side 32p defined by the downstream end plate 32 of the exhaust space 30s. In the second engagement step S3, the plurality of liner members 40 are not engaged with the inner diffuser 29 and the downstream end plate 32.

[0146] In the exhaust chamber 25 modified by the modification method of this embodiment, similarly to the exhaust chamber 25 of the first embodiment, the generation of steam backflow can be suppressed, thereby suppressing the exhaust resistance of steam. Moreover, in the exhaust chamber 25 modified by the modification method of this embodiment, the generation of welding deformation of the downstream end plate 32 and the inner diffuser 29 can be suppressed.

[0147] Furthermore, in this modification method, firstly, after the support column 45 is joined to the inner diffuser 29 or the downstream end plate 32, the inner liner component 40 is joined to the support column 45 from the radially outer side (Dro) towards the radially inner side (Dri) within the diffuser space 26s and the exhaust space 30s. Therefore, in this method, the inner liner component 40 can be easily joined to the support column 45.

[0148] Industrial availability

[0149] According to one aspect of the present invention, steam exhaust resistance can be suppressed. Furthermore, according to one aspect of the present invention, welding deformation of the inner diffuser and downstream end plate can be suppressed.

[0150] Symbol Explanation

[0151] 10a - First steam turbine section, 10b - Second steam turbine section, 11 - Turbine rotor, 12 - Rotor shaft, 13 - Moving blades, 13a - Last stage moving blades, 17 - Stationary blades, 18 - Bearing, 19 - Steam inlet pipe, 20 - Shell, 21 - Trunk shell, 25, 25a, 25b - Exhaust chamber, 26 - Diffuser, 26s - Diffuser space, 27 - Outer diffuser, 27p - Space side, 29 - Inner diffuser, 29p - Space side, 30 - Exhaust shell, 30s - Exhaust space, 31 - Exhaust port, 32 - Downstream end plate, 32p - Space side, 34 - Upstream end plate , 36-Outer peripheral plate, 40-Inner liner component, 41-Inner liner plate, 41p-Space side, 41pa-Anti-space side, 41o-Outer edge, 41i-Inner edge, 41s-Side edge, 42-Opening, 43-Reinforcing rib, 43a-First reinforcing rib, 43b-Second reinforcing rib, 45-Support column, 45a-First end, 45b-Second end, Co-Condenser, Ar-Axis axis, Da-Axis direction, Dau-Upstream side of axis, Dad-Downstream side of axis, Dc-Circumferential, Dr-Radial, Dri-Radially inner side, Dro-Radially outer side, Dpu-Non-exhaust side, Dpe-Exhaust side.

Claims

1. An exhaust chamber for a steam turbine, capable of discharging steam flowing from the last-stage moving blades of a turbine rotor rotating about an axis to the outside, said exhaust chamber comprising: A diffuser forms a diffuser space that allows steam flowing out from the last stage moving blades to flow in, is annular relative to the axis, and gradually expands radially outward relative to the axis as it moves downstream of the axis. The exhaust casing has an exhaust port that opens toward the radially outward side and communicates with the diffuser space, extending circumferentially relative to the axis to form an exhaust space that guides steam flowing into the diffuser space to the exhaust port. Multiple liner components are configured to extend from the diffuser space across the exhaust space and are arranged circumferentially; and Support columns are provided for each of the plurality of inner lining components. The diffuser has an inner diffuser, the cross-section of which is annular relative to the axis, gradually expanding radially outward towards the downstream side of the axis, and defining the radially inner edge of the diffuser space relative to the axis. The exhaust housing has a downstream end plate that defines the edge of the exhaust space downstream of the axis. The downstream end plate extends along a direction including a radial component relative to the axis and in the circumferential direction. The radially inner edge of the downstream end plate connects to the downstream edge of the axis of the inner diffuser. The plurality of liner components extend from a position along the radially inner edge of the diffuser space defined by the inner diffuser, gradually moving towards the downstream side of the axis as they move towards the radially outer side, to a position along the spatial side of the exhaust space defined by the downstream end plate. Each of the plurality of lining components has a first end and a second end as its support column. The first end of the support column engages with the inner diffuser or the downstream end plate. The second end of the support column engages with any one of the plurality of lining components. None of the multiple liner components are engaged with the inner diffuser and the downstream end plate.

2. The exhaust chamber according to claim 1, wherein, The plurality of inner lining components do not contact the inner diffuser.

3. The exhaust chamber according to claim 1, wherein, The plurality of inner lining components do not contact the downstream end plate.

4. The exhaust chamber according to claim 1, wherein, The plurality of inner lining components do not contact each other.

5. The exhaust chamber according to claim 1, wherein, The plurality of lining components are arranged with reference to the axis on at least the non-exhaust side of the exhaust side where the exhaust port is located and the non-exhaust side opposite to the exhaust side.

6. The exhaust chamber according to claim 1, wherein, The plurality of lining components are positioned relative to the axis and are located only on the non-exhaust side, which is the exhaust side where the exhaust port is located and on the non-exhaust side opposite to the exhaust side.

7. The exhaust chamber according to claim 1, wherein, In the plurality of liner components arranged along the circumference, the radial length of the liner component located on the non-exhaust side, opposite to the exhaust side where the exhaust port is located, is longer than the radial length of the liner component located on the exhaust side.

8. The exhaust chamber according to claim 1, wherein, The support column is cylindrical. Each of the plurality of liner components has a liner plate that extends from a position along the spatial side of the inner diffuser toward the radially outward side toward the downstream side of the axis, to a position along the spatial side of the downstream end plate. A circular opening is formed in the inner lining plate. The second end of the support column enters the opening of the liner and engages with the edge of the opening.

9. The exhaust chamber according to claim 1, wherein, Each of the plurality of liner components has: a liner plate extending from a position along the spatial side of the inner diffuser toward the radially outer side toward the downstream side of the axis, to a position along the spatial side of the downstream end plate; and one or more reinforcing ribs engaging with the anti-spatial side of the liner plate toward the radially inner side.

10. The exhaust chamber according to claim 9, wherein, One or more reinforcing ribs include: a first reinforcing rib disposed on one side of the circumferential direction in the liner, with reference to its engagement position with the support column; and a second reinforcing rib disposed on the other side of the circumferential direction. Both the first reinforcing rib and the second reinforcing rib extend along the anti-space side in a manner that gradually moves toward the downstream side of the axis as it moves toward the radially outward side.

11. The exhaust chamber according to claim 10, wherein, The circumferential spacing between the first reinforcing rib and the second reinforcing rib gradually widens as it moves toward the downstream side of the axis.

12. A steam turbine comprising: The exhaust chamber according to any one of claims 1 to 11; The turbine rotor; and A casing that covers the outer periphery of the turbine rotor.

13. A method for modifying the exhaust chamber of a steam turbine, which enables the steam flowing from the last-stage moving blades of a turbine rotor rotating around its axis to be discharged to the outside, wherein, The exhaust chamber includes: A diffuser, forming a diffuser space, into which steam exiting from the last-stage moving blades of a turbine rotor rotating about an axis flows in, forming an annular shape relative to the axis and gradually expanding radially outward relative to the axis as it moves downstream of the axis; and The exhaust casing has an exhaust port that opens towards the radially outward side and communicates with the diffuser space, extending circumferentially relative to the axis, thereby forming an exhaust space that guides steam flowing into the diffuser space to the exhaust port. The diffuser has an inner diffuser, the cross-section of which is annular relative to the axis, gradually expanding radially outward towards the downstream side of the axis, and defining the radially inner edge of the diffuser space relative to the axis. The exhaust housing has a downstream end plate that defines the edge of the exhaust space downstream of the axis. The downstream end plate extends along a direction including a radial component relative to the axis and in the circumferential direction. The radially inner edge of the downstream end plate connects to the downstream edge of the axis of the inner diffuser. The following procedures are performed in the modification method of this exhaust chamber: The preparation process involves preparing multiple inner lining components and their respective support columns. In the first joining step, the first end of the first end and the second end of the support column are joined to the inner diffuser or the downstream end plate, so that the support columns of the plurality of liner components are spaced apart from each other in the circumferential direction. and In the second joining process, the plurality of inner liner components are respectively joined to the second end of any one of the support columns, such that the plurality of inner liner components are arranged circumferentially, and each of the plurality of inner liner components extends from a position outside the space along the radially inner edge of the diffuser space defined by the inner diffuser, gradually moving towards the downstream side of the axis as it moves towards the radially outer side, to a position along the side of the exhaust space defined by the downstream end plate. In the second joining process, the plurality of inner liner components are not joined to the inner diffuser and the downstream end plate.

Images