Seal detachment jig, seal detachment method, and seal part

Abstract

To easily detach a seal part from a casing.SOLUTION: A seal detachment jig is used to detach a seal part from a casing of a rotating machine. The seal detachment jig comprises a jig body to be pushed up from below in a vertical direction by a jack, and a jig fixing part for detachably fixing the jig body to an end surface of the seal part. The jig body comprises: a jig contact part capable of being in contact with an end surface of an upper half seal part or a lower half seal part in a circumferential direction around an axis of the rotating machine; and a jig protrusion part protruding outward in a radial direction with respect to the jig contact part, and to be pushed up from below in the vertical direction by the jack. The ratio of a first distance to the outside diameter of the upper half seal part or the lower half seal part is 0.01 or more and 0.1 or less.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a seal removal tool, a seal removal method, and a seal portion. [Background technology]

[0002] A multi-stage centrifugal compressor is known as a compressor having multiple stages of impellers that compress gas. In a multi-stage centrifugal compressor, gas is drawn into a casing through a suction port, compressed sequentially by multiple stages of impellers, and then discharged out of the casing through a discharge port.

[0003] In such a centrifugal compressor, an impeller is housed in a casing. The casing has a plurality of diaphragms that cover the impeller and a cylindrical outer casing that covers the plurality of diaphragms from the radial outside. For example, Patent Document 1 describes a centrifugal compressor in which a seal is used to seal between the rotating impeller and the stationary diaphragm. The seal in Patent Document 1 seals the radial gap between the impeller cover and the diaphragm. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-150035 A Summary of the Invention [Problem to be solved by the invention]

[0005] Such a seal is formed in a semicircular ring shape. The seal is fixed to the inner circumferential surface of a member constituting the casing, such as a diaphragm divided into upper and lower parts. As the size of the centrifugal compressor increases, the casing and seal become larger. Therefore, removing the seal from the casing during maintenance becomes a complex task. Furthermore, when the working fluid to be compressed is a fluid such as ethylene-based gas, adhesion occurs between the casing and the seal, making removal even more difficult. Therefore, it is desirable to be able to easily remove the seal from the casing.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a seal removal tool, a seal removal method, and a seal portion that can easily remove a seal portion from a casing. [Means for solving the problem]

[0007] In order to solve the above problems, a seal removal jig according to the present disclosure is a seal removal jig used when removing a seal portion from a casing of a rotary machine, and includes a jig main body that is pushed up from below in the vertical direction by a jack, and a jig fixing part that detachably fixes the jig main body to the seal portion, the casing is capable of accommodating an impeller that is rotatable about an axis line therein, and has a casing inner peripheral surface that faces an outer peripheral surface of the impeller in a radial direction based on the axis line, the seal portion is arranged on the casing inner peripheral surface and faces the outer peripheral surface of the impeller from the outside in the radial direction so as to be able to seal a gap with the impeller, the casing forms an upper part in the vertical direction with respect to the axis line, and has an upper half that forms a semicircular arc in cross section perpendicular to the axis line, and a lower half that forms a semicircular arc in cross section perpendicular to the axis line and a lower half portion having a semicircular cross section perpendicular to the axis, the seal portion further having an upper half seal portion attached to the upper half portion and a lower half seal portion attached to the lower half portion, the jig body having a jig contact portion capable of contacting an end face of the upper half seal portion or the lower half seal portion in a circumferential direction centered on the axis, and a jig protruding portion that protrudes radially outward from the jig contact portion and is pushed up from below in the vertical direction by a jack, wherein a first distance is defined as the horizontal distance between a fixed center position of the jig fixing portion with respect to the end face and a load-bearing position of the jig protruding portion with which the jack makes contact and to which a force from the jack is applied, and the ratio of the first distance to the outer diameter of the upper half seal portion or the lower half seal portion is 0.01 or more and 0.1 or less.

[0008] Furthermore, the seal removal method according to the present disclosure is a seal removal method using the seal removal jig, and includes the steps of positioning the upper half or the lower half so that the end face of the upper half seal or the lower half seal faces upward in the vertical direction, positioning the jig body in contact with the end face and fixing the end face and the jig body with the jig fixing portion, and using the jack to push the jig protruding portion upward from below in the vertical direction.

[0009] Further, a seal portion according to the present disclosure is a seal portion that can house an impeller rotatable about an axis therein, the seal portion including a casing having an inner peripheral surface of the casing facing an outer peripheral surface of the impeller in a radial direction based on the axis, an upper half portion that forms an upper portion in a direction perpendicular to the axis and has a semicircular arc shape in cross section perpendicular to the axis, and a lower half portion that forms a lower portion in the direction perpendicular to the axis and has a semicircular arc shape in cross section perpendicular to the axis, and the seal portion is capable of sealing a gap with the impeller, the seal portion having an L-shaped cross section when viewed from the circumferential direction, and is disposed on the inner peripheral surface of the casing so as to face the outer peripheral surface of the impeller from the outside in the radial direction, The casing has an upper half seal portion attached to the upper half portion and a lower half seal portion attached to the lower half portion, and the upper half portion and the lower half portion have seal mounting recesses formed therein that are recessed radially from the inner peripheral surface of the casing, and the upper half seal portion and the lower half seal portion have a seal main body on which a seal surface that faces the outer peripheral surface of the impeller from the outside in the radial direction is formed, and a seal insertion portion that protrudes radially from the seal main body and can be inserted radially into the seal mounting recess, and the surface of the seal insertion portion that faces the inner surface of the recess extending radially in the seal mounting recess is formed only by an insertion surface that extends radially and is capable of sliding contact with the inner surface of the recess. [Effects of the Invention]

[0010] According to the seal removal tool, seal removal method, and seal portion of the present disclosure, the seal portion can be easily removed from the casing. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a cross-sectional view of a centrifugal compressor according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing the configuration of the impeller and its surroundings of the centrifugal compressor. [Figure 3] FIG. 2 is a cross-sectional view showing a seal portion of the centrifugal compressor as viewed from the axial direction. [Figure 4]FIG. 4 is an enlarged cross-sectional view illustrating the sealing portion. [Figure 5] FIG. 2 is a cross-sectional view showing the seal removal tool of the present disclosure. [Figure 6] FIG. 1 is a flow diagram illustrating a seal removal method of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, with reference to the accompanying drawings, an embodiment for carrying out the seal removal jig 8, the seal removal method S1, and the seal unit 5 according to the present disclosure will be described. However, the present disclosure is not limited to only this embodiment.

[0013] (Configuration of centrifugal compressor) First, a centrifugal compressor 1 to which the seal removal jig 8, seal removal method S1, and seal unit 5 of the present disclosure are applied will be described. As shown in Fig. 1, the centrifugal compressor 1 in this embodiment is a single-shaft multi-stage centrifugal compressor. The centrifugal compressor 1 mainly includes a rotating shaft 2 that rotates about an axis O, a casing 10 formed to surround the rotating shaft 2, and a seal unit 5.

[0014] (Configuration of the rotating shaft) The rotating shaft 2 extends in the axial direction Da. The rotating shaft 2 extends so as to penetrate the inside of the casing 10 along the axis O. The rotating shaft 2 has a rotating shaft main body 21 and an impeller 22.

[0015] In this embodiment, the direction in which the axis O extends is referred to as the axial direction Da. The axial direction Da of the rotating shaft 2 is along a horizontal plane. In other words, the axis O extends horizontally. The radial direction based on the axis O is simply referred to as the radial direction Dr. Furthermore, the direction around the rotating shaft 2 centered on the axis O is referred to as the circumferential direction Dc.

[0016] The rotating shaft body 21 is formed in a cylindrical shape extending in the axial direction Da. An end of the rotating shaft body 21 on a first side Da1 in the axial direction Da is supported by the casing 10 by a journal bearing 32A and a thrust bearing 31 so as to be rotatable about the axis O. An end of the rotating shaft body 21 on a second side Da2 in the axial direction Da is supported by the casing 10 by a journal bearing 32B so as to be rotatable about the axis O.

[0017] The impeller 22 is arranged on the outer side Dro of the rotary shaft body 21 in a radial direction Dr based on the axis O. A plurality of impellers 22 are arranged in the casing 10, spaced apart from each other in the axial direction Da.

[0018] Each impeller 22 compresses and discharges a working fluid (e.g., gas) supplied from a first side Da1 in the axial direction Da to an outer side Dro in the radial direction Dr. An impeller flow path 23 is formed inside each impeller 22. The cross-sectional area of ​​the impeller flow path 23 gradually decreases from the inner side Dri in the radial direction Dr to the outer side Dro in the radial direction Dr. As a result, the working fluid flowing through the impeller flow path 23 while the impeller 22 is rotating is gradually compressed and becomes highly pressurized.

[0019] (Casing configuration) The casing 10 is formed to surround the rotary shaft main body 21 and the plurality of impellers 22 from the outer side Dro in the radial direction Dr. The casing 10 includes an outer casing 11, a suction port 111, a discharge port 112, a plurality of diaphragms 15, and a head 17.

[0020] The outer casing 11 is formed in a cylindrical shape extending in the axial direction Da. The outer casing 11 is formed so as to cover the rotating shaft 2, the plurality of diaphragms 15, and the head 17 from the outside Dro in the radial direction Dr.

[0021] The outer casing 11 has an upper half casing 11A above the vertical direction Dv and a lower half casing 11B below the vertical direction Dv. The upper half casing 11A and the lower half casing 11B are fixed together by detachable fixing means such as bolts.

[0022] The upper half casing 11A has a cross section perpendicular to the axis O that forms a semicircular ring shape centered on the axis O and extends in the axial direction Da. The upper half casing 11A opens downward in the vertical direction Dv so that the multiple diaphragms 15 can fit into it. As a result, the upper half casing 11A covers from above the outer peripheral surfaces of the multiple diaphragms 15 housed inside.

[0023] The lower half casing 11B has a cross section perpendicular to the axis O that forms a semicircular ring shape centered on the axis O and extends in the axial direction Da. The lower half casing 11B opens upward in the vertical direction Dv so that the multiple diaphragms 15 can fit into it. As a result, the lower half casing 11B covers from below the outer peripheral surfaces of the multiple diaphragms 15 housed inside.

[0024] The suction port 111 is formed on a first side Da1 in the axial direction Da of the outer casing 11. The suction port 111 allows the working fluid to flow into the outer casing 11 from the outside.

[0025] The discharge port 112 is formed on the second side Da2 in the axial direction Da of the outer casing 11. The discharge port 112 discharges the working fluid compressed through all the impellers 22 inside the outer casing 11 to the outside of the outer casing 11. In other words, the discharge port 112 is disposed away from the suction port 111 on the second side Da2 in the axial direction Da.

[0026] The multiple diaphragms 15 are arranged on the inner side Dri of the outer casing 11 in the radial direction Dr. The multiple diaphragms 15 are formed as a whole in a cylindrical shape extending in the axial direction Da so as to cover the impellers 22 of each stage. Each diaphragm 15 is formed in a disk shape centered on the axis O. The multiple diaphragms 15 are stacked in the axial direction Da, and adjacent diaphragms 15 are fixed to each other by welding or bolts. By being fixed to each other, the multiple diaphragms 15 cover the periphery of the rotating shaft 2 and form a casing flow path 40 therein that connects the multiple impellers 22. The multiple diaphragms 15, together with the rotating shaft 2, the head 17, the journal bearings 32A and 32B, and the thrust bearing 31, form a bundle. The bundle is housed in the outer casing 11. In the bundle, the plurality of diaphragms 15, the rotary shaft 2, the head 17, the journal bearings 32A and 32B, and the thrust bearing 31 are movable together to form a single unit.

[0027] Each diaphragm 15 has an upper half diaphragm (upper half) 15A that forms a semicircular ring above the vertical direction Dv based on the center line of the rotation shaft 2, and a lower half diaphragm (lower half) 15B that forms a semicircular ring below the vertical direction Dv based on the center line of the rotation shaft 2. The upper half diaphragm 15A and the lower half diaphragm 15B are fixed by detachable fixing means such as bolts.

[0028] The upper half diaphragm 15A extends in the circumferential direction Dc so that a cross section perpendicular to the axis O forms a semicircular ring shape centered on the axis O. The upper half diaphragm 15A opens downward in the vertical direction Dv so as to cover the upper half of the impeller 22. As a result, the upper half diaphragm 15A accommodates the upper half of the impeller 22 inside so as to cover the impeller 22 from above.

[0029] The lower half diaphragm 15B extends in the circumferential direction Dc so that a cross section perpendicular to the axis O forms a semicircular ring shape centered on the axis O. The lower half diaphragm 15B opens upward in the vertical direction Dv so that the lower half of the impeller 22 fits into it. As a result, the lower half diaphragm 15B accommodates the lower half of the impeller 22 inside so as to cover the impeller 22 from below.

[0030] The diaphragms 15 also have a casing flow path 40 including an introduction flow path 41, a diffuser flow path 42, and a return flow path 43.

[0031] The introduction flow path 41 guides the working fluid from the outer side Dro in the radial direction Dr toward the inner side Dri in the radial direction Dr. The introduction flow path 41 changes the working fluid heading toward the inner side Dri in the radial direction Dr into a flow toward the second side Da2 in the axial direction Da, and guides it to the impeller 22. In this way, the introduction flow path 41 changes the flow direction of the working fluid to the second side Da2 in the axial direction Da, and guides it to the impeller flow path 23 of the impeller 22.

[0032] The diffuser passage 42 extends from the inner side Dri to the outer side Dro in the radial direction Dr. An end of the diffuser passage 42 on the inner side Dri in the radial direction Dr is connected to an end of the impeller passage 23 on the outer side Dro in the radial direction Dr. The diffuser passage 42 guides the working fluid compressed by the impeller 22 from the inner side Dri in the radial direction Dr to the outer side Dro in the radial direction Dr.

[0033] The return flow passage 43 reverses the flow direction of the working fluid that has passed through the diffuser flow passage 42 and flowed from the inner side Dri in the radial direction Dr to the outer side Dro in the radial direction Dr. The return flow passage 43 guides the working fluid flowing toward the outer side Dro in the radial direction Dr to the inner side Dri in the radial direction Dr. One end of the return flow passage 43 (a first side Da1 in the axial direction Da), which is upstream in the flow direction of the working fluid, is connected to the diffuser flow passage 42. The other end of the return flow passage 43 (a second side Da2 in the axial direction Da), which is downstream in the flow direction of the working fluid, is connected to the subsequent introduction flow passage 41.

[0034] A pair of heads 17 are arranged to close openings at both ends in the axial direction Da of the cylindrical outer casing 11. They are annular members centered on the axis O. The pair of heads 17 are arranged inside the outer casing 11. The heads 17 of this embodiment have a first casing head 171 and a second casing head 172.

[0035] The first casing head 171 is disposed so as to close an opening on a first side Da1 in the axial direction Da of the outer casing 11. That is, the first casing head 171 is disposed adjacent to the first side Da1 in the axial direction Da with respect to the plurality of diaphragms 15. A suction scroll that takes in external working fluid into the casing flow path 40 through the suction port 111 is formed between the first casing head 171 and the first-stage diaphragm 15, which is disposed furthest to the first side Da1 in the axial direction Da, among the plurality of diaphragms 15. The first casing head 171 is fixed to the plurality of integrated diaphragms 15 with bolts or the like. As a result, the first casing head 171 is integrated with the diaphragms 15.

[0036] The second casing head 172 is disposed so as to close an opening on the second side Da2 in the axial direction Da of the outer casing 11. In other words, the second casing head 172 is disposed adjacent to the multiple diaphragms 15 on the second side Da2 in the axial direction Da. Therefore, the second casing head 172 is adjacent to the final-stage diaphragm 15 of the multiple diaphragms 15, which is disposed furthest on the second side Da2 in the axial direction Da. The second casing head 172 is fixed to the integrated multiple diaphragms 15 with bolts or the like. In this way, the second casing head 172 is integrated with the diaphragms 15.

[0037] (Impeller detailed configuration) Next, the detailed configuration of the impeller 22 will be described with reference to Fig. 2. The impeller 22 is a so-called closed impeller having a disk 25, blades 26, and a cover 27.

[0038] The disk 25 is formed in a disk shape centered on the axis O. A through-hole 251 is formed in the disk 25, which has a circular shape centered on the axis O and penetrates in the axial direction Da. The inner peripheral surface of the through-hole 251 fits into the outer peripheral surface of the rotating shaft 2, thereby fixing the impeller 22 integrally to the rotating shaft 2.

[0039] The surface of the disk 25 facing the second side Da2 in the axial direction Da is a disk back surface 252 that is planar and perpendicular to the axis O. A disk main surface 253 is formed from the end of the through hole 251 on the first side Da1 in the axial direction Da to the end of the disk back surface 252 on the outer side Dro in the radial direction Dr. The disk main surface 253 extends so as to gradually widen toward the outer side Dro in the radial direction Dr as it moves from the first side Da1 in the axial direction Da to the other side. The disk main surface 253 on the first side Da1 in the axial direction Da faces the outer side Dro in the radial direction Dr, and gradually curves toward the first side Da1 in the axial direction Da as it moves toward the second side Da2 in the axial direction Da. That is, the disk main surface 253 gradually widens in diameter as it moves from the first side Da1 in the axial direction Da to the other side. The disk main surface 253 has a concave curved shape.

[0040] The blades 26 are arranged at intervals in the circumferential direction Dc of the axis O on the disk main surface 253 of the disk 25. Each blade 26 curves backward in the rotation direction of the impeller 22 as it moves from the inner side Dri in the radial direction Dr to the outer side Dro in the radial direction Dr. Each blade 26 extends while forming a curved surface that convexly faces forward in the rotation direction.

[0041] The cover 27 covers the plurality of blades 26 from a first side Da1 in the axial direction Da. The cover 27 is disposed opposite the disk 25 so that the blades 26 are sandwiched between the cover 27 and the disk 25. The inner circumferential surface of the cover 27 (hereinafter referred to as the cover inner circumferential surface 271) is formed so as to gradually increase in diameter from the first side Da1 to the other side in the axial direction Da. The cover inner circumferential surface 271 is curved while facing the disk main surface 253 so as to correspond to the disk main surface 253. Ends of the blades 26 on the opposite side to the disk main surface 253 are fixed to the cover inner circumferential surface 271. The cover inner circumferential surface 271, the disk main surface 253, and the blades 26 form an impeller flow path 23 therebetween, which curves in the circumferential direction Dc and extends to the outer side Dro in the radial direction Dr as it moves from the first side Da1 in the axial direction Da to the other side. The cover 27 also has a cover outer peripheral surface 272 that faces the opposite direction to the cover inner peripheral surface 271 and faces the inner peripheral surface of the casing 10. The cover outer peripheral surface 272 is the outer peripheral surface of the impeller 22.

[0042] (Casing structure around the impeller) Next, the detailed structure of the casing 10 will be described with reference to Fig. 2. The casing 10 has an impeller accommodating portion 151 between the inlet flow path 41 and the diffuser flow path 42 as a space for accommodating the impeller 22 inside Dri. A plurality of impeller accommodating portions 151 are formed corresponding to the number of impellers 22. One impeller accommodating portion 151 is formed for each diaphragm 15.

[0043] A portion of the impeller 22 facing the cover outer peripheral surface 272 is defined as a casing inner peripheral surface 152. An end portion of the casing inner peripheral surface 152 on a second side Da2 in the axial direction Da is connected to the diffuser flow path 42. An end portion of the casing inner peripheral surface 152 on a first side Da1 in the axial direction Da is connected to the introduction flow path 41. The casing inner peripheral surface 152 is formed as an inner peripheral surface of the diaphragm 15 facing inward Dri in the radial direction Dr.

[0044] The casing inner peripheral surface 152 has a seal mounting recess 155. The seal mounting recess 155 is recessed from the casing inner peripheral surface 152 toward the outer side Dro in the radial direction Dr. As shown in FIG. 4, a recess inner surface 157, which is the inner surface of the seal mounting recess 155, is a flat surface extending in the radial direction Dr. The recess inner surface 157 is a flat surface on which no protrusions or recesses are formed. In other words, the seal mounting recess 155 is recessed only toward the outer side Dro in the radial direction Dr, with the recess inner surface 157 being smooth. The seal mounting recess 155 is formed in the upper half diaphragm 15A and the lower half diaphragm 15B.

[0045] (Sealing part) As shown in Fig. 2, the seal unit 5 is capable of sealing the gap between the casing 10 and the impeller 22. The seal unit 5 of this embodiment is a labyrinth seal that seals the gap in the radial direction Dr between the cover outer peripheral surface 272 and the casing inner peripheral surface 152. The seal unit 5 is arranged on the casing inner peripheral surface 152 so as to face the cover outer peripheral surface 272, which is the outer peripheral surface of the impeller 22, from the outside Dro in the radial direction Dr. As shown in Fig. 1, the seal unit 5 has an upper half seal unit 5A attached to the upper half diaphragm 15A and a lower half seal unit 5B attached to the lower half diaphragm 15B.

[0046] As shown in FIG. 2, the upper half seal portion 5A is fixed to the upper half diaphragm 15A while being inserted into the seal mounting recess 155 of the upper half diaphragm 15A. As shown in FIG. 3, the movement of the upper half seal portion 5A in the vertical direction Dv is restricted by the head of a restriction bolt 19 fixed to the upper half diaphragm 15A, preventing it from coming off the upper half diaphragm 15A. As shown in FIG. 2, the lower half seal portion 5B is fixed to the lower half diaphragm 15B while being inserted into the seal mounting recess 155 of the lower half diaphragm 15B. As shown in FIG. 3, the movement of the lower half seal portion 5B in the vertical direction Dv is restricted by the head of a restriction bolt 19 fixed to the lower half diaphragm 15B, preventing it from coming off the lower half diaphragm 15B. The upper half seal portion 5A and the lower half seal portion 5B are formed to have the same shape. The upper half seal portion 5A and the lower half seal portion 5B are formed in a semi-annular shape when viewed from the axial direction Da. Bolt insertion holes 52 are formed in end faces 51 of the upper half seal portion 5A and the lower half seal portion 5B in the circumferential direction Dc. When attached to the upper half diaphragm 15A or the lower half diaphragm 15B, the end face 51 is positioned at the same position as the dividing plane, which is the end face of the upper half diaphragm 15A or the lower half diaphragm 15B in the circumferential direction Dc. The bolt insertion holes 52 are threaded holes into which headless bolts such as long screws are inserted for fastening. The upper half seal portion 5A and the lower half seal portion 5B are fastened to each other by fastening the bolts in the bolt insertion holes 52 of the upper half seal portion 5A and the lower half seal portion 5B. As shown in FIG. 4 , the upper half seal portion 5A and the lower half seal portion 5B each have a seal body 55 and a seal insertion portion 56.

[0047] The seal body 55 is formed with a seal surface 551 that faces the outer circumferential surface of the impeller 22 from the outside Dro in the radial direction Dr. The seal body 55 is formed in a semi-annular shape with the inner circumferential surface serving as the seal surface 551. Fins that protrude toward the outer circumferential surface of the impeller 22 are formed on the seal surface 551.

[0048] The seal insertion portion 56 protrudes from the seal main body 55 toward the outer side Dro in the radial direction Dr. The seal insertion portion 56 is insertable into the seal mounting recess 155 in the radial direction Dr. The seal insertion portion 56 protrudes from the end of the seal main body 55 on the second side Da2 in the axial direction Da. As a result, the seal portion 5 has an L-shaped cross section when viewed from the circumferential direction Dc. The seal insertion portion 56 has an insertion surface 561 that faces the recess inner surface 157. The insertion surface 561 is formed as a flat surface that extends in the radial direction Dr and is capable of sliding contact with the recess inner surface 157. In other words, the insertion surface 561 is a smooth surface that is free of irregularities that may catch on the recess inner surface 157, such as recesses, protrusions, or curved surfaces.

[0049] (Seal removal tool) Next, the seal removal jig 8 used when removing the seal portion 5 from the casing 10 will be described. As shown in FIG. 5 , the seal removal jig 8 of this embodiment is used when removing the upper half seal portion 5A from the upper half diaphragm 15A and when removing the lower half seal portion 5B from the lower half diaphragm 15B. One seal removal jig 8 is disposed on each end face 51 of the upper half seal portion 5A or the lower half seal portion 5B. The seal removal jig 8 of this embodiment has a jig main body 81 and a jig fixing portion 82. Therefore, the jig main body 81 and the jig fixing portion 82 can be independently disposed on both the end face 51 of the upper half seal portion 5A or the end face 51 of the lower half seal portion 5B in the circumferential direction Dc.

[0050] The jig body 81 is pushed up from below in the vertical direction Dv by the jack 9. The jig body 81 of this embodiment has a jig contact portion 811 and a jig protruding portion 812.

[0051] The jig contact portion 811 is capable of contacting the end face 51 of the upper half seal portion 5A or the lower half seal portion 5B in the circumferential direction Dc. The jig contact portion 811 is formed in a rectangular parallelepiped shape so that its lower end can contact the end face 51 of the seal portion 5. The jig main body 81 has a jig through hole 816 that penetrates the interior in the vertical direction Dv. The jig through hole 816 is formed with a size that allows the jig fixing portion 82, which is inserted into the bolt insertion holes 52 formed in the upper half seal portion 5A and the lower half seal portion 5B, to pass through.

[0052] The jig protrusion 812 is pushed up from below in the vertical direction Dv by the jack 9. The jig protrusion 812 protrudes toward the outer side Dro in the radial direction Dr relative to the jig contact portion 811. The jig protrusion 812 is formed at a position spaced apart from the lower end of the jig contact portion 811 in the vertical direction Dv. The jig protrusion 812 protrudes only from the upper end of the jig contact portion 811 toward the outer side in the horizontal direction, that is, the outer side Dro in the radial direction Dr. In other words, when the seal removal jig 8 is fixed to the upper half seal portion 5A or the lower half seal portion 5B, the jig protrusion 812 is formed at a position spaced apart from the end surface 51 of the upper half seal portion 5A or the lower half seal portion 5B in the vertical direction Dv. The jig protrusion 812 is formed integrally with the jig contact portion 811. The jig protrusion 812 also has a supported surface 817 that comes into contact with the jack 9. The supported surface 817 is a flat surface facing downward in the vertical direction Dv.

[0053] The jig fixing portion 82 detachably fixes the jig body 81 to the end surface 51 of the seal portion 5. In this embodiment, the jig fixing portion 82 is a bolt member that is detachably attached to the bolt insertion hole 52. The jig fixing portion 82 is formed in a shape that can be inserted into the jig through hole 816. The jig fixing portion 82 has a head portion with a diameter larger than that of the jig through hole 816.

[0054] (jack) The jack 9 is a jack with claws 91. The jack with claws 91 is hydraulic, and is capable of lifting a heavy object from a low position by placing the claws 91 under the heavy object. In other words, even if there is not enough space under the heavy object for the entire jack 9 to fit, the jack 9 can lift the heavy object by simply placing the claws 91 under the heavy object and moving the claws 91 upward in the vertical direction Dv.

[0055] Here, the position where the jig fixing portion 82 is fixed to the end face 51 of the upper half seal portion 5A or the lower half seal portion 5B is referred to as the fixed center position. The fixed center position is the horizontal center position of the jig through hole 816. Furthermore, the load point on the jig protruding portion 812 where the jack 9 contacts and the force from the jack 9 is applied is referred to as the loaded position. The loaded position is the position where the jig protruding portion 812 contacts the claw 91 of the jack 9, and is the horizontal center position of the contact portion between the supported surface 817 and the claw 91. Furthermore, the horizontal distance between the fixed center position and the loaded position is referred to as the first distance A. The first distance A is the horizontal length between the fixed center position and the loaded position when viewed from the axial direction Da. In other words, the first distance A is a value representing the amount of protrusion of the jig protruding portion 812 from the jig contact portion 811 in the radial direction Dr.

[0056] It is preferable that the amount of protrusion of the jig protruding portion 812 from the jig contact portion 811 in the radial direction Dr be kept as small as possible. Specifically, it is preferable that the ratio of the first distance A to the outer diameter of the seal portion 5 (upper half seal portion 5A or lower half seal portion 5B) be 0.01 or more and 0.1 or less. It is more preferable that the ratio of the first distance A to the outer diameter of the seal portion 5 be 0.01 or more and 0.04 or less. It is even more preferable that the ratio of the first distance A to the outer diameter of the seal portion 5 be 0.01 or more and 0.25 or less. Furthermore, in order to accommodate seal portions 5 of a plurality of sizes, it is preferable that the first distance A in the seal removal jig 8 be constant regardless of the outer diameter of the seal portion 5.

[0057] (How to remove the seal) The seal unit 5 described above is removed from the casing 10 by a seal removal method S1 using a seal removal jig 8. In the seal removal method S1, the seal removal jig 8 attached to the seal unit 5 is lifted with a jack 9 to remove the seal unit 5 from the casing 10. The seal removal method S1 is applicable to both the upper half diaphragm 15A and the lower half diaphragm 15B. However, for the sake of explanation, this embodiment only exemplifies the removal of the lower half seal unit 5B from the lower half diaphragm 15B. Note that a similar procedure is also used when removing the upper half seal unit 5A from the upper half diaphragm 15A. Therefore, when removing the upper half seal unit 5A from the upper half diaphragm 15A, the lower half diaphragm (lower half) 15B is replaced with the upper half diaphragm (upper half) 15A, and the lower half seal unit 5B is replaced with the upper half seal unit 5A.

[0058] As shown in Fig. 6, in the seal removal method S1, first, the upper half or the lower half is positioned (step S10). Specifically, the upper half diaphragm 15A or the lower half diaphragm 15B is positioned so that the end face 51 of the upper half seal portion 5A or the lower half seal portion 5B faces upward in the vertical direction Dv. For example, the lower half diaphragm 15B is positioned so that its opening faces upward in the vertical direction Dv. At this time, it is preferable that the lower half diaphragm 15B is removed from the lower half casing 11B, but depending on the structure of the centrifugal compressor 1, it may remain housed in the lower half casing 11B.

[0059] After the lower half diaphragm 15B is placed, the seal removal jig 8 is fixed to the end face 51 of the lower half seal portion 5B (step S20). Specifically, the jig body 81 is placed in contact with the end face 51 of the lower half seal portion 5B. At this time, the jig body 81 is placed so that the bolt insertion holes 52 and the jig through holes 816 are horizontally aligned. Thereafter, the end face 51 of the lower half seal portion 5B and the jig body 81 are fixed by the jig fixing portion 82. Specifically, the jig fixing portion 82 is inserted through the jig through holes 816, and the jig fixing portion 82 is fixed to the bolt insertion holes 52 with the head of the jig fixing portion 82 in contact with the upper end of the jig contact portion 811. This fixes the jig body 81 so that it cannot move relative to the lower half seal portion 5B.

[0060] After the lower half seal portion 5B and the jig main body 81 are fixed, the jig protruding portion 812 is pushed upward from below in the vertical direction Dv by the jack 9 (step S30). Specifically, the claw 91 is inserted below the jig protruding portion 812 and brought into contact with the supported surface 817. The jack 9 is then operated to move the claw 91 upward in the vertical direction Dv. As a result, the jig protruding portion 812 is pushed upward from below in the vertical direction Dv by the claw 91. This causes the jig protruding portion 812 to be pulled out from the seal insertion portion 56 inserted in the seal mounting recess 155, and the lower half seal portion 5B is peeled off from the lower half diaphragm 15B even if the lower half seal portion 5B and the lower half diaphragm 15B are fixed together.

[0061] (Action and effect) In the seal removal jig 8 and seal removal method S1 configured as described above, the jig body 81 is fixed in contact with the lower half seal portion 5B by the jig protrusion 812. The ratio of the first distance A to the outer diameter of the seal portion 5 is 0.01 or greater and 0.1 or less. That is, the fixed center position of the jig fixing portion 82 relative to the end face 51 of the lower half seal portion 5B and the load-bearing position of the jig protrusion 812 to which the force from the jack 9 is applied are very close to each other. Therefore, when the jig protrusion 812 is lifted using the jack 9, the moment generated in the jig protrusion 812 about the fixed center position can be suppressed. Therefore, when the jig protrusion 812 is lifted using the jack 9, rotation of the jig body 81 relative to the end face 51 of the lower half seal portion 5B can be suppressed. As a result, the force received from the jack 9 can be accurately transmitted to the end face 51 of the lower half seal portion 5B via the jig body 81. This allows the lower half seal portion 5B to be moved straight upward in the vertical direction Dv relative to the lower half diaphragm 15B, and the lower half seal portion 5B to be peeled off from the lower half diaphragm 15B. Therefore, the seal portion 5 can be easily removed from the casing 10.

[0062] Furthermore, the jig body 81 and the jig fixing portion 82 can be independently arranged on both end faces 51 of the seal unit 5 in the circumferential direction Dc. In other words, two jig bodies 81 and two jig fixing portions 82 can be independently arranged for one lower half seal unit 5B. Therefore, both ends of the lower half seal unit 5B can be pushed upward in the vertical direction Dv while minimizing the space occupied by the seal removal jig 8. Furthermore, by arranging the jig bodies 81 on both ends, the amount of upward movement of both ends of the lower half seal unit 5B in the vertical direction Dv relative to the lower half diaphragm 15B can be adjusted using two jacks 9. Therefore, the lower half seal unit 5B can be peeled off from the lower half diaphragm 15B while maintaining a stable posture. This makes it easier to remove the seal unit 5 from the casing 10.

[0063] Moreover, the jig protruding portion 812 protrudes only toward the outer side Dro in the radial direction Dr relative to the jig contact portion 811. Therefore, it is possible to ensure an area for contacting the jack 9 while suppressing the size of the jig main body 81 in the radial direction Dr.

[0064] Furthermore, a jack with claws 91 is used as the jack 9. Therefore, the claws 91 can be inserted under the jig protrusion 812 without ensuring a large space under the jig protrusion 812. This reduces the distance in the vertical direction Dv between the end surface 51 of the lower half seal portion 5B and the jig protrusion 812. It is possible to ensure an area for contact with the jack 9 while reducing the size of the jig main body 81 in the vertical direction Dv.

[0065] The seal unit 5 also has a seal insertion portion 56 that is inserted into the seal mounting recess 155. The surface of the seal insertion portion 56 that faces the recess inner surface 157 is formed solely by an insertion surface 561 that extends in the radial direction Dr. In other words, the flat recess inner surface 157 and the flat insertion surface 561 face each other across the radial direction Dr while extending parallel to each other. This prevents the seal insertion portion 56 from getting caught on the seal mounting recess 155 when inserting or removing the seal insertion portion 56 into or from the seal mounting recess 155. This allows the lower half seal unit 5B to be removed from the lower half diaphragm 15B with reduced resistance when removing the seal unit 5 using the seal removal jig 8. This makes it easier to remove the seal unit 5 from the casing 10.

[0066] Furthermore, the movement of the lower half seal portion 5B in the vertical direction Dv is restricted by the restricting bolt 19 fixed to the lower half diaphragm 15B, so that the lower half seal portion 5B cannot fall off from the lower half diaphragm 15B. Therefore, even if the seal insertion portion 56 is not caught in the seal mounting recess 155, it is possible to prevent the lower half seal portion 5B from falling off from the lower half diaphragm 15B.

[0067] (Other embodiments) The above describes in detail the embodiments of the present disclosure with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present disclosure.

[0068] It should be noted that the casing 10 is not limited to a structure having the outer casing 11 and the diaphragm 15. For example, the casing 10 may have a structure that does not have the diaphragm 15. In such a structure, the seal portion 5 has an upper half seal portion 5A and a lower half seal portion 5B that are directly attached to the upper half and lower half of the semi-annular casing 10.

[0069] Furthermore, the centrifugal compressor 1 is not limited to being a straight-type single-shaft multi-stage centrifugal compressor in which all of the impellers 22 face the same direction as in this embodiment. The centrifugal compressor 1 may be a back-to-back single-shaft multi-stage centrifugal compressor in which the impellers 22 face in opposite directions in the axial direction Da, or a geared compressor.

[0070] Furthermore, the seal portion 5 removed by the seal removal jig 8 is not limited to a structure having only the seal main body 55 and the seal insertion portion 56, as in this embodiment. For example, the seal portion 5 may have a structure in which recesses and protrusions are formed in the seal insertion portion 56.

[0071] Furthermore, the seal removal jig 8 is not limited to the structure of this embodiment. For example, the seal removal jig 8 is not limited to a structure in which it is independently and simultaneously placed on both the end faces 51 of the upper half seal portion 5A and the lower half seal portion 5B in the circumferential direction Dc. Furthermore, the seal removal jig 8 is not limited to a structure having only the jig contact portion 811 and the jig protruding portion 812.

[0072] <Additional Notes> The seal removal jig 8, seal removal method S1, and seal unit 5 described in the embodiment can be understood, for example, as follows.

[0073] (1) The seal removal jig 8 according to the first aspect is a seal removal jig 8 used when removing a seal portion 5 from a casing 10 of a rotary machine, and includes a jig body 81 that is pushed up from below in a vertical direction Dv by a jack 9, and a jig fixing part 82 that detachably fixes the jig body 81 to the seal portion 5, and the casing 10 is capable of accommodating therein an impeller 22 that can rotate around an axis O, and the impeller 22 is rotatable about the axis O in a radial direction Dr based on the axis O. The casing 10 has a casing inner peripheral surface 152 facing the outer peripheral surface of the impeller 22, and the seal portion 5 is arranged on the casing inner peripheral surface 152 and faces the outer peripheral surface of the impeller 22 from the outside Dro in the radial direction Dr to be able to seal the gap with the impeller 22. The casing 10 has an upper half portion that forms an upper part in the vertical direction Dv with respect to the axis O, and a cross section perpendicular to the axis O is semicircular arc-shaped, and a lower part in the vertical direction Dv with respect to the axis O. The seal portion 5 further has an upper half seal portion 5A attached to the upper half portion and a lower half seal portion 5B attached to the lower half portion, and the jig body 81 has a jig contact portion 811 that can come into contact with an end face 51 of the upper half seal portion 5A or the lower half seal portion 5B in a circumferential direction Dc about the axis O, and a jig contact portion 811 that faces an outer side Dro in the radial direction Dr with respect to the jig contact portion 811. The jig has a jig protrusion 812 that protrudes upward and is pushed up from below in the vertical direction Dv by a jack 9, and when the horizontal distance between the fixed center position of the jig fixing portion 82 with respect to the end face 51 and the load-bearing position of the jig protrusion 812 where the jack 9 comes into contact and where the force from the jack 9 is applied is defined as a first distance A, the ratio of the first distance A to the outer diameter of the upper half seal portion 5A or the lower half seal portion 5B is 0.01 or more and 0.1 or less.

[0074] With this configuration, the fixed center position of the jig fixing portion 82 relative to the end face 51 of the upper half seal portion 5A or the lower half seal portion 5B is very close to the load-bearing position of the jig protruding portion 812 to which the force from the jack 9 is applied. Therefore, when the jig protruding portion 812 is lifted using the jack 9, the moment generated in the jig protruding portion 812 about the fixed center position can be reduced. Therefore, when the jig protruding portion 812 is lifted using the jack 9, rotation of the jig main body 81 relative to the end face 51 of the upper half seal portion 5A or the lower half seal portion 5B can be reduced. As a result, the force received from the jack 9 can be accurately transmitted to the end face 51 of the upper half seal portion 5A or the lower half seal portion 5B via the jig main body 81. This allows the upper half seal portion 5A to move straight upward in the vertical direction Dv relative to the upper half diaphragm 15A, thereby peeling the upper half seal portion 5A off the upper half diaphragm 15A. Similarly, the lower half seal portion 5B can be moved straight upward in the vertical direction Dv relative to the lower half diaphragm 15B, and can be peeled off from the lower half diaphragm 15B. Therefore, the seal portion 5 can be easily removed from the casing 10.

[0075] (2) The seal removal jig 8 of the second aspect is the seal removal jig 8 of (1), in which the jig body 81 and the jig fixing portion 82 can be independently positioned on both the end face 51 of the upper half seal portion 5A or the lower half seal portion 5B in the circumferential direction Dc.

[0076] With this configuration, two independent jig bodies 81 and jig fixing portions 82 can be arranged for one upper half seal portion 5A or one lower half seal portion 5B. Therefore, both ends of the upper half seal portion 5A or the lower half seal portion 5B can be pushed upward in the vertical direction Dv while minimizing the space occupied by the seal removal jig 8. Furthermore, by arranging the jig bodies 81 at both ends, the amount of upward movement of both ends of the upper half seal portion 5A in the vertical direction Dv relative to the upper half diaphragm 15A can be adjusted using two jacks 9. Therefore, the upper half seal portion 5A can be peeled off from the upper half diaphragm 15A while maintaining a stable position. Similarly, the amount of upward movement of both ends of the lower half seal portion 5B in the vertical direction Dv relative to the lower half diaphragm 15B can be adjusted. Therefore, the lower half seal portion 5B can be peeled off from the lower half diaphragm 15B while maintaining a stable position. Therefore, the seal portion 5 can be more easily removed from the casing 10.

[0077] (3) The seal removal jig 8 according to the third aspect is the seal removal jig 8 of (1) or (2), in which the jig protrusion 812 protrudes only toward the outer side Dro in the radial direction Dr relative to the jig contact portion 811.

[0078] According to this configuration, it is possible to ensure an area for contacting the jack 9 while suppressing the size of the jig body 81 in the radial direction Dr.

[0079] (4) A seal removal method S1 according to a fourth aspect is a seal removal method S1 using a seal removal jig 8 of any one of (1) to (3), and includes the steps of positioning the upper half or the lower half so that the end face 51 of the upper half seal portion 5A or the lower half seal portion 5B faces upward in the vertical direction Dv, positioning the jig body 81 in contact with the end face 51 and fixing the end face 51 and the jig body 81 with the jig fixing portion 82, and pushing the jig protrusion 812 upward from below in the vertical direction Dv using the jack 9.

[0080] With this configuration, two independent jig bodies 81 and jig fixing portions 82 can be arranged for one upper half seal portion 5A or one lower half seal portion 5B. Therefore, both ends of the upper half seal portion 5A or the lower half seal portion 5B can be pushed upward in the vertical direction Dv while minimizing the space occupied by the seal removal jig 8. Furthermore, by arranging the jig bodies 81 at both ends, the amount of upward movement of both ends of the upper half seal portion 5A in the vertical direction Dv relative to the upper half diaphragm 15A can be adjusted using two jacks 9. Therefore, the upper half seal portion 5A can be peeled off from the upper half diaphragm 15A while maintaining a stable position. Similarly, the amount of upward movement of both ends of the lower half seal portion 5B in the vertical direction Dv relative to the lower half diaphragm 15B can be adjusted. Therefore, the lower half seal portion 5B can be peeled off from the lower half diaphragm 15B while maintaining a stable position. Therefore, the seal portion 5 can be more easily removed from the casing 10.

[0081] (5) A fifth aspect of the seal removal method S1 is the seal removal method S1 of (4), in which the jack 9 is a jack 9 with a claw 91, and after the non-contact surface of the jig protrusion 812 facing downward in the vertical direction Dv is brought into contact with the upper surface of the claw 91 of the jack 9 facing upward in the vertical direction Dv, the jig protrusion 812 is pushed upward from below in the vertical direction Dv.

[0082] With this configuration, the claws 91 can be inserted under the jig protrusion 812 without ensuring a large space under the jig protrusion 812. Therefore, it is possible to reduce the distance in the vertical direction Dv between the end face 51 of the upper half seal portion 5A or the lower half seal portion 5B and the jig protrusion 812. It is possible to ensure an area for contact with the jack 9 while reducing the size of the jig main body 81 in the vertical direction Dv.

[0083] (6) A seal unit 5 according to a sixth aspect is a seal unit 5 capable of sealing a gap between a casing 10 and the impeller 22, the seal unit 5 being capable of accommodating therein an impeller 22 rotatable about an axis O, the seal unit 5 including: a casing inner peripheral surface 152 facing an outer peripheral surface of the impeller 22 in a radial direction Dr based on the axis O; an upper half portion forming an upper portion in a vertical direction Dv with respect to the axis O and having a semicircular arc cross section perpendicular to the axis O; and a lower half portion forming a lower portion in the vertical direction Dv with respect to the axis O and having a semicircular arc cross section perpendicular to the axis O; and the seal unit 5 being capable of sealing a gap between the casing 10 and the impeller 22, the seal unit 5 having an L-shaped cross section when viewed from a circumferential direction Dc centered on the axis O, and being disposed on the casing inner peripheral surface 152 so as to face the outer peripheral surface of the impeller 22 from an outside Dro in the radial direction Dr, and the upper half portion The casing 22 has an upper half seal portion 5A attached to the casing 22 and a lower half seal portion 5B attached to the lower half portion, and the upper half portion and the lower half portion form a seal mounting recess 155 recessed in the radial direction Dr from the casing inner surface 152, and the upper half seal portion 5A and the lower half seal portion 5B have a seal main body 55 on which a seal surface 551 is formed that faces the outer peripheral surface of the impeller 22 from the outside Dro in the radial direction Dr, and a seal insertion portion 56 that protrudes from the seal main body 55 in the radial direction Dr and can be inserted into the seal mounting recess 155 in the radial direction Dr, and the surface of the seal insertion portion 56 that faces a recess inner surface 157 extending in the radial direction Dr in the seal mounting recess 155 is formed only by an insertion surface 561 that is capable of sliding contact with the recess inner surface 157 and extends in the radial direction Dr.

[0084] With this configuration, the recess inner surface 157 and the flat insertion surface 561 face each other in the radial direction Dr. Therefore, when the seal insertion portion 56 is inserted into or removed from the seal mounting recess 155, the seal insertion portion 56 is prevented from getting caught on the seal mounting recess 155. Therefore, when removing the seal portion 5 with the seal removal jig 8, the upper half seal portion 5A can be removed from the upper half diaphragm 15A with little resistance. Similarly, the lower half seal portion 5B can be removed from the lower half diaphragm 15B with little resistance. This makes it easier to remove the seal portion 5 from the casing 10. [Explanation of symbols]

[0085] 1...Centrifugal compressor O…Central axis 2...Rotation axis 21...Rotating shaft body 22...Impeller 23...Impeller passage 25...Disc 251...Through hole 252...Back of disc 253...Main surface of disk 26...Blade 27...Cover 271...Inner surface of cover 272...Cover outer surface 10...Casing 11...Outer casing 111...Intake port 112…Discharge port 11A...Upper casing 11B...Lower casing 15...Diaphragm 15A...Upper diaphragm 15B...Lower diaphragm 151...Impeller housing 152... Casing inner surface 155...Seal mounting recess 157...Inner surface of recess 40...Casing flow path 41...Inlet channel 42...Diffuser flow path 43...Return flow path 17...Head 171...First casing head 172...Second casing head 5...Sealing part 5A...Upper seal part 5B...Lower seal part 51...End face 52...Bolt insertion hole 55...Seal body 551...Sealing surface 56...Seal insertion part 561...insertion surface 19...Regulation bolt 31...Thrust bearing 32A, 32B...Journal bearings S1...Seal removal method 8...Seal removal tool 81...Jig body 811...Jig contact part 812...Jig protrusion 816...Jig through hole 817…Supported surface 82...Jig fixing part A…first distance 9...Jack 91...Claws Da...Axial direction Da1…first side Da2…Second side Dr…Radial direction Dro...outside Dri…inside Dc…Circumferential direction Dv: vertical direction

Claims

1. A seal removal tool used when removing a seal portion from a casing of a rotary machine, a jig body that is pushed up from below in the vertical direction by a jack; a jig fixing portion that detachably fixes the jig body to the seal portion, the casing is capable of accommodating therein an impeller rotatable about an axis, and has a casing inner peripheral surface facing an outer peripheral surface of the impeller in a radial direction based on the axis, the seal portion is disposed on the inner peripheral surface of the casing and faces the outer peripheral surface of the impeller from the outside in the radial direction to seal a gap between the impeller and the seal portion; The casing comprises: an upper half portion that forms an upper portion in the vertical direction with respect to the axis line and has a cross section perpendicular to the axis line that is semicircular; a lower half portion that forms a portion below the axis in the vertical direction and has a cross section perpendicular to the axis that is semicircular, The sealing portion is an upper half seal portion attached to the upper half portion; a lower half seal portion attached to the lower half portion, The jig body is a jig contact portion that can come into contact with an end surface of the upper half seal portion or the lower half seal portion in a circumferential direction about the axis; a jig protruding portion that protrudes radially outward relative to the jig contact portion and is pushed up from below in the vertical direction by a jack, A seal removal jig in which, when the horizontal distance between the fixed center position of the jig fixing portion relative to the end face and the load-bearing position of the jig protrusion portion where the jack comes into contact and the force from the jack is applied is defined as a first distance, the ratio of the first distance to the outer diameter of the upper half seal portion or the lower half seal portion is 0.01 or more and 0.1 or less.

2. The seal removal jig according to claim 1 , wherein the jig body and the jig fixing portion can be independently arranged on both of the end faces of the upper half seal portion and the lower half seal portion in the circumferential direction.

3. The seal removal jig according to claim 1 or 2, wherein the jig protruding portion protrudes only radially outward from the jig contact portion.

4. A seal removal method using the seal removal jig according to claim 1, positioning the upper half portion or the lower half portion such that the end surface of the upper half seal portion or the lower half seal portion faces upward in the vertical direction; placing the jig body in contact with the end surface and fixing the end surface and the jig body with the jig fixing portion; and a step of pushing the jig protrusion upward in the vertical direction using the jack.

5. The jack is a claw jack, 5. A seal removal method according to claim 4, wherein the non-contact surface of the jig protruding portion facing downward in the vertical direction is brought into contact with the upper surface of the jack claw facing upward in the vertical direction, and then the jig protruding portion is pushed upward from below in the vertical direction.

6. a casing inner peripheral surface that can accommodate an impeller rotatable about an axis and that faces an outer peripheral surface of the impeller in a radial direction based on the axis; an upper half portion that forms an upper portion in a direction vertical to the axis line and has a cross section perpendicular to the axis line that is semicircular; a casing having a lower half portion that forms a portion below the axis in the vertical direction and has a semicircular cross section perpendicular to the axis; A seal portion capable of sealing a gap with the impeller, The cross-sectional shape when viewed from the circumferential direction about the axis is formed in an L-shape, the impeller is disposed on the inner peripheral surface of the casing so as to face the outer peripheral surface of the impeller from the outside in the radial direction; an upper half seal portion attached to the upper half portion and a lower half seal portion attached to the lower half portion; The upper half portion and the lower half portion are formed with seal mounting recesses recessed in the radial direction from the inner peripheral surface of the casing, The upper half seal portion and the lower half seal portion are a seal body having a seal surface facing the outer peripheral surface of the impeller from the outside in the radial direction; a seal insertion portion that protrudes from the seal body in the radial direction and is insertable into the seal mounting recess in the radial direction, The seal insertion portion is a seal portion in which the surface facing the inner surface of the recess extending in the radial direction in the seal mounting recess is formed only by an insertion surface extending in the radial direction and capable of sliding contact with the inner surface of the recess.

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