Maintenance method of steam turbine and steam turbine

Abstract

A maintenance method for a steam turbine, which is a maintenance method for a steam turbine including a rotor, a casing for housing the rotor, and a bearing housing for housing bearings that support the rotor, wherein the maintenance method for the steam turbine includes: a step of providing a telescopic member using an upward-facing flat surface located between the casing and the bearing housing in the axial direction below the rotor; and a step of pushing up the rotor upward using the telescopic member.

Description

Technical Field

[0001] The present invention relates to a maintenance method for a steam turbine and a steam turbine.

[0002] This application claims priority based on Japanese Patent Application No. 2020-093637 filed with the Japan Patent Office on May 28, 2020, and incorporates its content herein. Background Art

[0003] When maintaining a steam turbine, in order to remove internal objects (such as bearings) from the casing housing the rotor, the rotor is sometimes lifted, and for this purpose, telescopic members such as hydraulic jacks are sometimes used.

[0004] Patent Document 1 does not relate to maintenance, but Patent Document 1 describes that a jack provided inside a bearing housing assists in the floating of a turbine rotor during turbine startup.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2012-62872 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] However, in recent years, in order to reduce the cost and improve the performance of steam turbines, the axial length of turbines has a tendency to be shortened. Along with this, the bearing housing that houses the bearings for supporting the turbine rotor also has a tendency to be shortened axially. As a result, there is a situation where the space inside or near the bearing housing becomes narrow, and it is not easy to set telescopic members (such as hydraulic jacks) during maintenance, resulting in a decrease in maintainability.

[0010] In view of the above situation, an object of at least one embodiment of the present invention is to provide a maintenance method for a steam turbine and a steam turbine that can suppress a decrease in maintainability associated with the shortening of the steam turbine.

[0011] Means for Solving the Problems

[0012] A maintenance method for a steam turbine according to at least one embodiment of the present invention is a maintenance method for a steam turbine including a rotor, a casing for housing the rotor, and a bearing housing for housing bearings that support the rotor, wherein,

[0013] The maintenance method for the steam turbine includes:

[0014] A step of setting a telescopic member by using a flat surface axially located between the casing and the bearing housing below the rotor; and

[0015] The step of pushing up the rotor upward by using the telescopic member.

[0016] In addition, a steam turbine according to at least one embodiment of the present invention includes:

[0017] A rotor;

[0018] A casing for housing the rotor;

[0019] A bearing housing for housing a bearing that supports the rotor; and

[0020] A protruding portion that protrudes axially from the bearing housing toward the casing below the rotor and can be fitted into the casing,

[0021] The protruding portion has an upper surface that is a flat surface located between the casing and the bearing housing in the axial direction below the rotor.

[0022] Advantageous Effects of the Invention

[0023] According to at least one embodiment of the present invention, there are provided a maintenance method for a steam turbine and a steam turbine that can suppress a decrease in maintainability associated with shortening of the steam turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of a steam turbine according to one embodiment.

[0025] Figure 2 is including Figure 1 A schematic cross-sectional view of the bearing housing of the steam turbine shown.

[0026] Figure 3A is including Figure 2 A partial cross-sectional view of the steam turbine of the A-A cross-section.

[0027] Figure 3B is showing Figure 3A The B-B cross-section of.

[0028] Figure 4 is a flowchart of a maintenance method according to one embodiment.

[0029] Figure 5 is a diagram for explaining the steps of a maintenance method according to one embodiment.

[0030] Figure 6 is a diagram for explaining the steps of a maintenance method according to one embodiment.

[0031] Figure 7 is showing Figure 6 The C-C cross-section of. DETAILED DESCRIPTION OF THE INVENTION

[0032] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. Among them, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples.

[0033] (Structure of steam turbine)

[0034] Figure 1 is a schematic diagram of a steam turbine according to an embodiment. Figure 2 includes Figure 1 is a schematic cross-sectional view of the bearing housing of the steam turbine shown. Figure 3A includes Figure 2 is a partial cross-sectional view of the steam turbine of the A-A section including Figure 3B shows Figure 3A is a view of the B-B section of

[0035] As Figure 1 and Figure 2 shown, a steam turbine 1 according to an embodiment includes: a rotor 5 (refer to Figure 2 ), which is rotatable about a central axis O; a casing 2, which is provided so as to cover the rotor 5; a bearing 6 (refer to Figure 2 ), which supports the rotor 5 so as to be rotatable; and a bearing housing 10, which is for housing the bearing 6. As Figure 2 shown, the rotor 5 is provided so as to penetrate the casing 2 and the bearing housing 10. It should be noted that a steam flow path is provided inside the casing 2, and the casing 2 houses a plurality of blades (not shown) provided in the steam flow path around the rotor 5.

[0036] The casing 2 includes an upper half casing 2A located on the upper side in the vertical direction (i.e., the vertical direction), and a lower half casing 2B located on the lower side in the vertical direction. The upper flange portion 3A provided on the upper half casing 2A and the lower flange portion 3B provided on the lower half casing 2B are fastened and connected by bolts (not shown).

[0037] The casing 2 is supported by a casing support portion 8 fixed to a base 7. In the illustrated embodiment, the lower half casing 2B has cat feet 4 protruding in the axial direction (the direction of the central axis O of the rotor), and is supported by the casing support portion 8 by means of the cat feet 4. It should be noted that in the Figure 1 shown casing 2, in the lower half casing 2B, a pair of cat feet 4 are provided on both sides of the central axis O in a plan view at both axial ends, that is, a total of 4 cat feet 4 are provided in the lower half casing 2B.

[0038] The bearing housing 10 includes an upper half 10A of the bearing housing located on the upper side in the vertical direction and a lower half 10B of the bearing housing located on the lower side in the vertical direction. The upper half 10A of the bearing housing and the lower half 10B of the bearing housing are fixedly connected by bolts (not shown) or the like. The bearing housing 10 is provided on the base 7. The bearing housing 10 may also include a bearing pedestal portion 46 for supporting the bearing 6 and a seal mounting portion 48 for mounting a seal member 24 described later. The bearing pedestal portion 46 is provided so as to at least partially overlap the bearing 6 in the axial direction and has axial end faces 47a, 47b.

[0039] As Figure 2 shown, in a through hole 11 of the bearing housing 10 provided based on the rotor 5, a seal member 24 for suppressing leakage of fluid (such as oil) from the inside of the bearing housing 10 to the outside space is provided. In one embodiment, the seal member 24 includes: a ring member 25 provided so as to surround the rotor 5 on the radially outer side of the rotor 5; and a fin portion 27 provided in a gap between the rotor 5 and the ring member 25 in the radial direction. The ring member 25 has a plurality of bolt holes extending in the axial direction, and the seal member 24 is mounted on the seal mounting portion 48 of the bearing housing 10 by screwing bolts 26 into the bolt holes. The seal mounting portion 48 may also be provided so as to axially protrude from the axial end face 47a on the machine room side of the axial end faces 47a, 47b of the bearing pedestal portion 46 toward the machine room 2. In addition, the seal mounting portion 48 may also be provided so as to be adjacent to the seal member 24 in the axial direction.

[0040] The seal member 24 may also have a structure that can be divided into an upper half and a lower half. Figure 2 The seal member 24 shown includes an upper half 24A of the seal member located on the upper side in the vertical direction and a lower half 24B of the seal member located on the lower side in the vertical direction, and has a structure that can be divided into an upper half and a lower half.

[0041] As Figure 1 and Figure 2 shown, the steam turbine 1 includes a protruding portion 16 that axially protrudes from the bearing housing 10 toward the machine room 2 below the rotor 5 and can be fitted into the machine room 2. The protruding portion 16 is provided so as to axially protrude more than a portion of the bearing housing 10 and the base 7 to which the bearing housing 10 is fixed that are opposed to each other in the vertical direction. In the illustrated embodiment, the protruding portion 16 is provided so as to axially protrude from the lower half 10B of the bearing housing.

[0042] In addition, the machine room 2 of the steam turbine 1 has a groove portion 15 that can be fitted with the above-mentioned protruding portion 16 below the rotor. In the illustrated embodiment, the groove portion 15 is provided in a receiving portion 14 provided so as to axially protrude from the lower half 2B of the machine room toward the bearing housing 10. A fitting portion 13 is formed by fitting the protruding portion 16 and the groove portion 15.

[0043] As Figure 3A and Figure 3B shown, with the protrusion 16 on the bearing housing 10 side engaged with the groove portion 15 on the machine chamber 2 side, a gap is formed between the front end face 16a of the protrusion 16 and the bottom face 15a of the groove portion 15, allowing for relative axial movement of the machine chamber 2 relative to the bearing housing 10 caused by thermal elongation or the like. Additionally, as Figure 3A shown, when viewed from above, there is almost no gap in the direction orthogonal to the central axis of the rotor 5 between the protrusion 16 and the groove portion 15, restricting relative movement of the machine chamber 2 relative to the bearing housing 10 in this direction. Therefore, through the engagement of the protrusion 16 and the groove portion 15, relative axial movement of the machine chamber 2 relative to the bearing housing 10 is allowed, and centering of the bearing housing 10 and the machine chamber 2 can be achieved. It should be noted that Figure 3A the straight line O' in represents the position of the central axis O of the rotor 5 when viewed from above.

[0044] In Figures 2 to 3B the exemplary embodiment shown, the protrusion 16 protruding axially from the bearing housing 10 includes a base portion 18 connected to the bearing housing 10 and a front end portion 20 located on the side closer to the machine chamber 2 than the base portion 18. The base portion 18 has an upper surface 19 located above the upper surface 21 of the front end portion 20. The front end portion 20 is at least partially located below the upper surface of the base 7 on which the bearing housing 10 is provided.

[0045] In the case where the bearing housing 10 is axially shortened along with the shortening of the steam turbine 1, for purposes such as preventing the bearing housing 10 from tipping over, there may be a case where the bearing housing 10 is also shortened in the vertical direction. In this case, it is necessary to set the upper surface of the base 7 at a position higher than before. On the other hand, the structure on the machine chamber 2 side remains unchanged, so the position of the groove portion 15 on the machine chamber 2 side engaged with the protrusion 16 on the bearing housing 10 side remains unchanged, and the engagement position of the groove portion 15 and the protrusion 16 remains unchanged. Therefore, the protrusion 16 engages with the groove portion 15 at a position below the installation position of the bearing housing 10 on the base 7. Thus, in the axially shortened steam turbine 1, in order to enable proper engagement of the protrusion 16 and the groove portion 15, the protrusion 16 has a base portion 18 connected to the machine chamber 2 and a front end portion 20 at least partially located below the upper surface of the base 7 as described above. Additionally, the front end portion 20 is at least partially located below the bottom face of the bearing housing 10. It should be noted that the base 7 refers to the base on which the bearing housing 10 is provided, and the bearing housing 10 is provided on the upper surface of the base 7.

[0046] The steam turbine 1 has an upward flat surface 12 located between the machine chamber 2 and the bearing housing 10 below the rotor 5. As described later, during the maintenance of the steam turbine 1, a telescopic member (such as a hydraulic jack) for pushing up the rotor 5 is arranged using this flat surface 12. That is, the flat surface 12 is configured to be able to carry the telescopic member.

[0047] In several embodiments, the above-mentioned flat surface 12 may also be formed on the upper surface of a protruding portion 16 that protrudes axially from the bearing housing 10 toward the machine chamber 2 below the rotor 5. In Figures 2 to 3B the illustrated exemplary embodiment shown, the upper surface 19 of the base portion 18 in the protruding portion 16 functions as the above-mentioned flat surface 12.

[0048] It should be noted that the dimension in the vertical direction of the portion of the base portion 18 of the protruding portion 16 where the flat surface 12 exists is larger than the dimension in the vertical direction of the front end portion 20. And, the dimension in the vertical direction of the portion of the base portion 18 where the flat surface 12 exists is larger than the dimension in the vertical direction of the portion of the base portion 18 that is closer to the bearing housing 10 than the portion where the flat surface 12 exists.

[0049] The flat surface 12, for example, as Figure 2 shown, may also be located below the sealing member 24 provided in the bearing housing 10. In this case, during maintenance, the space formed by removing the sealing member 24 can be used to arrange the telescopic member.

[0050] In addition, for example, as Figure 2 shown, the flat surface 12 may also be located axially on the side closer to the bearing housing 10 than the fitting portion 13 that fits into the groove portion 15 (machine chamber 2) of the receiving portion 14 in the protruding portion 16. In this case, it is easy to avoid interference between the telescopic member arranged on the flat surface 12 and the machine chamber 10 during maintenance.

[0051] In addition, for example, as Figure 2 shown, it may also be that a sealing mounting portion 48 protruding axially from the bearing pedestal portion 46 of the bearing housing 10 is located in the vertical direction (up and down direction) between the rotor 5 and the flat surface 12 and is arranged adjacent to the sealing member 24 axially. In this case, a space is formed in the region radially outside the sealing member 24 and the sealing mounting portion 48, so that when the sealing member 24 is removed during maintenance, this space can be used to easily arrange the telescopic member.

[0052] In addition, a concave portion or a convex portion into which a jig (described later) capable of carrying the telescopic member can be fitted may also be provided on the flat surface 12. In this case, the jig can be appropriately arranged on the flat surface 12 in a relatively narrow space. In Figures 2 to 3BIn the exemplary embodiment shown, a recess 22 that is recessed downward is provided on the upper surface 19 of the base 18 of the protruding portion 16 that is the flat surface 12, and this recess can engage with the protruding portion provided on the above-described jig.

[0053] (Maintenance method for steam turbine)

[0054] Hereinafter, according to Figure 4 the flowchart shown, the maintenance method for the steam turbine of several embodiments will be described. Here, the above-described steam turbine 1 will be described as an example of the object to be maintained. Figure 4 is a flowchart of the maintenance method of one embodiment. Figure 5 And Figure 6 are respectively diagrams for explaining the steps of the maintenance method of one embodiment, and are schematic cross-sectional views of the bearing housing including the same steam turbine as Figure 2 shown. Figure 7 is a diagram showing Figure 6 the C-C cross section of

[0055] In the maintenance method of one embodiment, first, the bolts that fasten and connect the upper half 10A of the bearing housing (refer to Figure 2 ) to the lower half 10B of the bearing housing are removed, and the upper half 10A of the bearing housing is removed (step S102). In addition, the sealing member 24 is removed by removing the bolts 26 (step S104). In addition, the upper half 2A of the machine room is removed. Thus, as Figure 5 shown, the upper half of the steam turbine 1 is in an open state, and it becomes a state where the rotor 5 can be lifted.

[0056] It should be noted that step S102 and step S104 can be carried out sequentially, or at least partially simultaneously. For example, the upper half 24A of the sealing member can be removed while the upper half 10A of the bearing housing is removed, and then the lower half 24B of the sealing member can be removed.

[0057] Next, as Figure 6 and Figure 7 shown, a ring-shaped member 36 is provided facing the lower side region of the outer peripheral surface 5a of the rotor 5 (step S106). When the rotor 5 is pushed up in the subsequent steps, the pushing force generated by the telescopic member is applied to the rotor 5 via the ring-shaped member 36, so that the rotor 5 can be easily and properly pushed up. In step S106, the ring-shaped member 36 can also be provided in such a manner that at least a part of the ring-shaped member 36 is located in the space S1 (refer to Figure 2 ) formed by removing the sealing member 24 (refer to Figure 5 ) in step S104. It should be noted that when the rotor 5 is lifted without using the ring-shaped member 36, step S106 can be omitted.

[0058] Next, as Figure 6 and Figure 7 shown, a hydraulic jack (expansion and contraction member) 30 is provided using the upward flat surface 12 axially located between the machine chamber 2 and the bearing housing 10 below the rotor 5 (step S108).

[0059] In step S108, at least a part of the hydraulic jack 30 may be provided in such a manner that it is located in the space S1 (refer to Figure 2 ) formed by removing the seal member 24 (refer to Figure 5 ) in step S104.

[0060] As Figure 6 and Figure 7 shown, the above-mentioned flat surface 12 may also be the upper surface 19 of the base 18 of the above-mentioned protruding portion 16 protruding axially from the bearing housing 10 toward the machine chamber 2. That is, in step S108, the hydraulic jack 30 may be provided using the upper surface 19 of the base 18 as the flat surface 12.

[0061] In step S108, for example, as Figure 6 and Figure 7 shown, a jig 32 capable of mounting the hydraulic jack 30 may be provided on the flat surface 12, and the hydraulic jack 30 may be provided on the upper surface 33 of the jig 32. The jig 32 is configured to have an upper surface 33 at a height suitable for setting the hydraulic jack 30.

[0062] As Figure 6 and Figure 7 shown, the flat surface 12 may have a recess 22 (or a convex portion protruding upward) recessed downward, and the lower end portion of the jig 32 may have a convex portion 34 (or a recess recessed upward) protruding downward. By fitting the recess 22 (or convex portion) of the flat surface 12 with the convex portion 34 (or recess) of the jig 32, the jig 32 is provided on the flat surface 12.

[0063] It should be noted that although not particularly illustrated, in step S108, the hydraulic jack 30 may also be provided on the flat surface 12 (for example, the upper surface 19 of the base 18 of the protruding portion 16).

[0064] Next, using the hydraulic jack 30 provided in step S108, the pushing force of the hydraulic jack 30 is applied to the rotor to push the rotor 5 upward (step S110). In the case where the annular member 36 has been provided in step S106, the pushing force generated by the expansion and contraction member is applied to the rotor 5 via the annular member 36.

[0065] According to the method of the above-described embodiment, a hydraulic jack 30 (a telescopic member) is provided on the flat surface 12 that is axially located between the machine chamber 2 and the bearing housing 10 below the rotor 5. Therefore, for example, even when there is insufficient installation space in the bearing housing 10 or the like due to the shortening of the turbine, the hydraulic jack 30 can be easily installed using the flat surface 12 during maintenance. Thus, even when the steam turbine 1 is shortened axially, maintenance can be efficiently performed, and a decrease in maintainability associated with the shortening of the steam turbine 1 can be suppressed.

[0066] In step S110, the hydraulic jack 30 and the jack bolt 42 (refer to Figure 7 ) may be used in combination to lift the rotor 5 upward. In one embodiment, as Figure 7 shown, for example, an arm 38 having a through-hole 43 is mounted to a member 44 (such as the lower half 10B of the bearing housing) provided or fixed on the base 7 using a bolt 40. The front end of the jack bolt 42 passing through the through-hole 43 is screwed into a threaded hole 37 provided on the upper surface of the annular member 36. And by screwing the jack bolt 42 into the threaded hole 37, the rotor 5 and the annular member 36 can be jacked up relative to the lower half 2B of the machine chamber (machine chamber 2).

[0067] In this way, by using the hydraulic jack 30 and the jack bolt 42 in combination, a greater force can be applied to the rotor 5, and the rotor 5 can be lifted higher. In addition, by using the hydraulic jack 30 to push up the rotor 5, the height of the rotor 5 can be adjusted with good accuracy.

[0068] It should be noted that in the above-described embodiment, the case where the upper surface of the protruding portion 16 protruding axially from the bearing housing 10 is used as the flat surface 12 for the installation of the hydraulic jack 30 (telescopic member) has been described. However, in other embodiments, for example, the upward-facing surface of a beam axially provided between the machine chamber 2 and the bearing housing 10 may be used as the above-mentioned flat surface 12 for the installation of the hydraulic jack 30. The beam may be provided so as to extend along the axial direction or along a direction orthogonal to the axial direction in a plan view.

[0069] The content described in each of the above embodiments can be grasped as follows, for example.

[0070] (1) The maintenance method of a steam turbine according to at least one embodiment of the present invention is a maintenance method of a steam turbine (1) including a rotor (5), a machine chamber (2) for housing the rotor, and a bearing housing (10) for housing a bearing (6) that supports the rotor, wherein,

[0071] The maintenance method of the steam turbine includes:

[0072] A step (such as the above-mentioned step S108) of providing a telescopic member (such as the above-mentioned hydraulic jack 30) by using an upward flat surface (12) axially located between the machine chamber and the bearing box below the rotor; and

[0073] A step (such as the above-mentioned step S110) of pushing up the rotor upward by using the telescopic member.

[0074] According to the method in the above (1), since a telescopic member is provided by using the flat surface axially located between the machine chamber and the bearing box below the rotor, for example, even when there is insufficient installation space in the bearing box or the like due to the shortening of the turbine, the telescopic member can be easily provided by using the above-mentioned flat surface during maintenance. Therefore, according to the structure in the above (1), even when the steam turbine is shortened axially, maintenance can be efficiently performed, and a decrease in maintainability associated with the shortening of the steam turbine can be suppressed.

[0075] (2) In several embodiments, on the basis of the method in the above (1),

[0076] The maintenance method includes a step (such as the above-mentioned step S104) of removing a sealing member provided in a through-hole of the bearing box provided based on the rotor from the bearing box,

[0077] In the step of providing the telescopic member, the telescopic member is provided in such a manner that at least a part of the telescopic member is located in a space (S1) formed by removing the sealing member.

[0078] During the maintenance of the bearings of the steam turbine, the sealing member provided in the bearing box is usually removed. In this regard, according to the method in the above (2), the telescopic member is provided by using the space formed by removing the sealing member provided in the bearing box. Therefore, even without performing special operations for providing an installation space during maintenance, the telescopic member can be easily provided. Thus, a decrease in maintainability associated with the shortening of the steam turbine can be suppressed.

[0079] (3) In several embodiments, on the basis of the method in the above (1) or (2),

[0080] In the step of pushing up, a pushing force generated by the telescopic member is applied to the rotor via an annular member (36) provided on the lower side region facing the outer peripheral surface (5a) of the rotor.

[0081] According to the method in the above (3), the pushing force generated by the telescopic member is applied to the rotor via the annular member provided on the lower side region facing the outer peripheral surface of the rotor. Therefore, the pushing force generated by the telescopic member can be appropriately applied to the rotor to push up the rotor.

[0082] (4)In several embodiments, based on any one of the methods in (1) to (3) above,

[0083] the maintenance method includes the step of jacking up the rotor and the annular member relative to the machine chamber using a jacking bolt (42), the jacking bolt (42) passing through a through hole (43) provided in the arm (38), and the arm (38) being mounted on the base (7) or on a member (44) provided or fixed on the base.

[0084] According to the method in (4) above, for jacking up the rotor and using a telescopic member and a jacking bolt, the rotor can be jacked up more reliably upward.

[0085] (5)In several embodiments, based on any one of the methods in (1) to (4) above,

[0086] the steam turbine includes a protruding portion (16) that axially protrudes from the bearing housing toward the machine chamber below the rotor and can be fitted into the machine chamber.

[0087] The flat surface includes the upper surface of the protruding portion (for example, the upper surface 19 of the base 18 of the protruding portion 16 described above).

[0088] For the alignment of the machine chamber and the bearing housing, the steam turbine sometimes has a protruding portion that axially protrudes and can be fitted into the machine chamber. Regarding this point, according to the method in (5) above, the upper surface of the protruding portion that axially protrudes from the bearing housing toward the machine chamber below the rotor and can be fitted into the machine chamber can be used to easily set the telescopic member during maintenance. Thereby, the reduction in maintainability associated with the shortening of the steam turbine can be suppressed.

[0089] (6)In several embodiments, based on the method in (5) above,

[0090] In the step of setting the telescopic member, the telescopic member is set on the upper surface of the protruding portion.

[0091] According to the method in (6) above, the telescopic member is set on the upper surface of the protruding portion, so the telescopic member can be easily set during maintenance. Thereby, the reduction in maintainability associated with the shortening of the steam turbine can be suppressed.

[0092] (7)In several embodiments, based on the method in (5) above,

[0093] the maintenance method includes the step of setting a jig (32) capable of placing the telescopic member on the upper surface of the protruding portion.

[0094] In the step of setting the telescopic member, the telescopic member is set on the upper surface (33) of the jig.

[0095] According to the method of (7) above, the telescopic member is set on the upper surface of the jig provided on the upper surface of the protrusion, so that the telescopic member can be easily set during maintenance. Thus, it is possible to suppress the reduction in maintainability associated with the shortening of the steam turbine.

[0096] (8) In several embodiments, based on the method of (7) above,

[0097] In the step of setting the jig, the convex portion or concave portion (such as the convex portion 34 described above) provided at the lower portion of the jig is engaged with the concave portion or convex portion (such as the concave portion 22 described above) provided on the upper surface of the protrusion.

[0098] According to the method of (8) above, by engaging the convex portion or concave portion provided at the lower portion of the jig with the concave portion or convex portion provided on the upper surface of the protrusion, the jig can be easily and reliably set even when the installation space of the jig is narrow. Thus, the telescopic member can be easily set during maintenance, and accordingly, it is possible to suppress the reduction in maintainability associated with the shortening of the steam turbine.

[0099] (9) The steam turbine (1) according to at least one embodiment of the present invention includes:

[0100] A rotor (5);

[0101] A casing (2) for housing the rotor;

[0102] A bearing housing (10) for housing a bearing that supports the rotor; and

[0103] A protrusion (16) that protrudes axially from the bearing housing toward the casing below the rotor and can be engaged with the casing,

[0104] The protrusion has an upper surface (for example, the upper surface 19 of the base 18 of the protrusion 16 described above) that is a flat surface (12) facing upward and located between the casing and the bearing housing in the axial direction below the rotor, and the flat surface is configured to be able to support a telescopic member (such as the hydraulic jack described above) for pushing the rotor upward.

[0105] In order to align the casing and the bearing housing of a steam turbine, a protruding portion that protrudes axially and can be fitted into the casing is sometimes provided. Regarding this point, according to the structure of (9) above, the upper surface of the protruding portion that protrudes axially from the bearing housing toward the casing and can be fitted into the casing below the rotor can be used to easily install the telescopic member during maintenance. Therefore, according to the structure of (9) above, even when the steam turbine is shortened axially, maintenance can be performed efficiently, and a decrease in maintainability associated with the shortening of the steam turbine can be suppressed.

[0106] (10)In several embodiments, based on the structure of (9) above,

[0107] The steam turbine includes a sealing member (24) provided in a through portion of the bearing housing provided based on the rotor,

[0108] The upper surface of the protruding portion is located below the sealing member.

[0109] During maintenance of the bearings of the steam turbine, the sealing member provided in the bearing housing is usually removed. Regarding this point, according to the structure of (10) above, the space formed by removing the sealing member provided in the bearing housing can be used to install the telescopic member. Therefore, even without performing special operations for providing a setting space during maintenance, the telescopic member can be easily installed. Thus, a decrease in maintainability associated with the shortening of the steam turbine can be suppressed.

[0110] (11)In several embodiments, based on the structure of (10) above,

[0111] The bearing housing includes:

[0112] A bearing pedestal portion (46) for supporting the bearing; and

[0113] A seal mounting portion (48) provided in the vertical direction between the rotor and the flat surface, protruding axially from the axial end surface (47a) of the bearing pedestal portion toward the casing, and for providing the sealing member.

[0114] According to the structure of (11) above, a sealing member is provided in the seal mounting portion of the bearing housing, so a space is formed in the region radially outside the sealing member. Therefore, the space can be used to easily install the telescopic member when the sealing member is removed during maintenance. Thus, a decrease in maintainability associated with the shortening of the steam turbine can be suppressed.

[0115] (12)In several embodiments, based on any of the structures of (9) to (11) above,

[0116] On the upper surface of the protrusion, there is a recess or a protrusion (such as the above-mentioned recess 22) into which the fixture (32) can be fitted, and the fixture (32) can carry a telescopic member for pushing the rotor upward.

[0117] According to the structure of the above (12), a telescopic member can be arranged on the upper surface of the fixture arranged on the upper surface of the protrusion, so that the telescopic member can be easily arranged during maintenance. In addition, by fitting the recess or protrusion arranged on the upper surface of the protrusion with the fixture, the fixture can be easily and reliably arranged even when the installation space of the fixture is narrow. Therefore, it is possible to suppress the reduction in maintainability associated with the shortening of the steam turbine.

[0118] (13) In several embodiments, based on any of the structures in the above (9) to (12),

[0119] The protrusion includes:

[0120] A base portion (18) connected to the bearing housing; and

[0121] A front end portion (20) located on the side of the machine chamber with respect to the base portion.

[0122] The base portion has an upper surface (19) as the flat surface,

[0123] The upper surface of the base portion is located above the upper surface (21) of the front end portion.

[0124] According to the structure of the above (13), the upper surface of the base portion of the protrusion connected to the bearing housing can be used to easily arrange the telescopic member during maintenance. Therefore, according to the structure of the above (13), even when the steam turbine is shortened axially, maintenance can be efficiently performed, and the reduction in maintainability associated with the shortening of the steam turbine can be suppressed.

[0125] (14) In several embodiments, based on any of the structures in the above (9) to (13),

[0126] The flat surface is located on the side of the bearing housing with respect to the fitting portion (13) of the protrusion that fits with the machine chamber in the axial direction.

[0127] According to the structure of the above (14), the flat surface on which the telescopic member can be arranged is arranged on the side of the bearing housing with respect to the fitting portion of the protrusion that fits with the machine chamber, so it is easy to avoid interference between the telescopic member arranged on the flat surface and the machine chamber during maintenance.

[0128] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments, and also includes embodiments obtained by modifying the above-described embodiments and embodiments obtained by appropriately combining these embodiments.

[0129] In this specification, expressions indicating relative or absolute configurations, such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial", not only represent such strict configurations, but also represent states in which there are tolerances or displacements in relative positions by angles and distances to such an extent that the same functions can be obtained.

[0130] For example, expressions indicating equal states of things, such as "same", "equal", and "homogeneous", not only represent strictly equal states, but also represent states in which there are tolerances or differences to such an extent that the same functions can be obtained.

[0131] In addition, in this specification, expressions indicating shapes, such as a quadrilateral shape and a cylindrical shape, not only represent quadrilateral shapes, cylindrical shapes, etc. in a strictly geometric sense, but also represent shapes including concavo-convex portions, chamfered portions, etc. within a range where the same effects can be obtained.

[0132] In addition, in this specification, expressions such as "comprising", "including", or "having" a constituent element are not exclusive expressions that exclude the existence of other constituent elements.

[0133] Description of Reference Numerals

[0134] 1 Steam turbine

[0135] 2 Machine chamber

[0136] 2A Upper half of the machine chamber

[0137] 2B Lower half of the machine chamber

[0138] 3A Upper flange portion

[0139] 3B Lower flange portion

[0140] 4 Cat foot

[0141] 5 Rotor

[0142] 5a Outer peripheral surface

[0143] 6 Bearing

[0144] 7 Base

[0145] 8 Machine chamber support portion

[0146] 10 Bearing housing

[0147] 10A Upper half of the bearing housing

[0148] Lower half of the 10B bearing housing

[0149] 11 Through-hole

[0150] 12 Flat surface

[0151] 13 Fitting part

[0152] 14 Receiving part

[0153] 15 Groove part

[0154] 15a Bottom surface

[0155] 16 Protrusion

[0156] 16a Front end surface

[0157] 18 Base

[0158] 19 Upper surface

[0159] 20 Front end part

[0160] 21 Upper surface

[0161] 22 Concave part

[0162] 24 Sealing member

[0163] 24A Upper half of the sealing member

[0164] 24B Lower half of the sealing member

[0165] 25 Ring member

[0166] 26 Bolt

[0167] 27 Fin part

[0168] 30 Hydraulic jack

[0169] 32 Clamp

[0170] 33 Upper surface

[0171] 34 Protrusion

[0172] 36 Ring-shaped member

[0173] 37 Threaded hole

[0174] 38 Arm

[0175] 40 Bolt

[0176] 42 Jack bolt

[0177] 43 Through-hole

[0178] 44 Member

[0179] 46 Bearing table

[0180] 47a, 47b Axial end faces

[0181] 48 Sealing mounting part

[0182] O Central axis

[0183] S1 Space

Claims

1. A maintenance method for a steam turbine, the steam turbine including a turbine rotor, a casing for housing a portion of the turbine rotor provided with a plurality of blades, and a bearing housing for housing bearings that support the turbine rotor, wherein, the steam turbine has an upward flat surface below the turbine rotor and axially located between the casing and the bearing housing, the maintenance method for the steam turbine includes: a step of arranging a telescopic member using the flat surface; and a step of pushing up the turbine rotor upward using the telescopic member.

2. The maintenance method for the steam turbine according to claim 1, wherein, the maintenance method for the steam turbine includes a step of removing a sealing member provided in a through-hole of the bearing housing provided based on the turbine rotor from the bearing housing, in the step of arranging the telescopic member, the telescopic member is arranged such that at least a part of the telescopic member is located in a space formed by removing the sealing member.

3. The maintenance method for the steam turbine according to claim 1 or 2, wherein, in the step of pushing up, a pushing force generated by the telescopic member is applied to the turbine rotor via an annular member provided on a lower region facing the outer peripheral surface of the turbine rotor.

4. The maintenance method for the steam turbine according to claim 3, wherein, the maintenance method for the steam turbine includes a step of jacking up the turbine rotor and the annular member relative to the casing using a jacking bolt that passes through a through-hole provided in an arm, and the arm is mounted on a base for supporting the casing and the bearing housing or on a member provided on the base.

5. The maintenance method for the steam turbine according to claim 1 or 2, wherein, the steam turbine includes a protruding portion that protrudes axially from the bearing housing toward the casing below the turbine rotor and can be fitted into the casing, the flat surface includes the upper surface of the protruding portion.

6. The maintenance method for the steam turbine according to claim 5, wherein, in the step of arranging the telescopic member, the telescopic member is arranged on the upper surface of the protruding portion.

7. The maintenance method for the steam turbine according to claim 5, wherein, the maintenance method for the steam turbine includes a step of arranging a fixture capable of mounting the telescopic member on the upper surface of the protruding portion, in the step of arranging the telescopic member, the telescopic member is arranged on the upper surface of the fixture.

8. The maintenance method for the steam turbine according to claim 7, wherein, in the step of arranging the fixture, a convex portion or a concave portion provided on the lower part of the fixture is fitted with a concave portion or a convex portion provided on the upper surface of the protruding portion.

9. A steam turbine, wherein, the steam turbine includes: a turbine rotor; a casing for housing a portion of the turbine rotor provided with a plurality of blades; a bearing housing for housing bearings that support the turbine rotor; and A protrusion that axially protrudes from the bearing housing toward the machine chamber below the turbine rotor and is capable of fitting into the machine chamber. The protrusion has an upper surface that is an upward-facing flat surface located between the machine chamber and the bearing housing in the axial direction below the turbine rotor. The flat surface is configured to be able to support a telescopic member for pushing the turbine rotor upward.

10. The steam turbine according to claim 9, wherein The steam turbine includes a sealing member provided in a through-hole of the bearing housing provided based on the turbine rotor. The upper surface of the protrusion is located below the sealing member.

11. The steam turbine according to claim 10, wherein The bearing housing includes: A bearing pedestal for supporting the bearing; and A sealing mounting portion provided between the turbine rotor and the flat surface in the vertical direction, protruding axially from an axial end surface of the bearing pedestal toward the machine chamber, and provided with the sealing member.

12. The steam turbine according to any one of claims 9 to 11, wherein A concave portion or a convex portion into which a jig can be fitted is provided on the upper surface of the protrusion, and the jig can support a telescopic member for pushing the turbine rotor upward.

13. The steam turbine according to any one of claims 9 to 11, wherein The protrusion includes: A base portion connected to the bearing housing; and A front end portion located on the machine chamber side relative to the base portion. The base portion has an upper surface that is the flat surface. The upper surface of the base portion is located above the upper surface of the front end portion.

14. The steam turbine according to any one of claims 9 to 11, wherein The flat surface is located on the bearing housing side relative to a fitting portion of the protrusion that fits into the machine chamber in the axial direction.

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