Method for estimating seal clearance in axial flow rotating machinery

Abstract

To suppress man-hours for grasping a seal clearance of an axial flow rotating machine.SOLUTION: A clearance estimation method performs: an upper-half holding ring temporary axis grasping step for grasping an upper-half seal holding ring temporary axis of an upper-half seal holding ring; a lower-half holding ring temporary axis grasping step for grasping a lower-half holding ring temporary axis of a lower-half seal holding ring; an upper-half ring temporary radius measurement step for measuring an upper-half ring temporary radius from the upper-half holding ring temporary axis up to an internal peripheral edge of the upper-half seal ring; a lower-half ring temporary radius measurement step for measuring a lower-half ring temporary radius from the lower-half holding ring temporary axis up to an internal peripheral edge of a lower-half seal ring; a casing temporary axis grasping step for grasping a casing temporary axis of a lower casing; an assembled temporary axis grasping step for grasping an assembled temporary axis being a temporary center axis of the lower-half seal holding ring which is assembled into the lower-half casing; and a clearance calculation step for acquiring a clearance of the upper-half seal ring and a clearance of the lower-half seal ring on the basis of data which are obtained in each of the steps.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present disclosure relates to a method for estimating the seal clearance of an axial flow rotary machine that estimates the clearance between a seal ring and a rotor in the axial flow rotary machine.

Background Art

[0002] As a type of axial flow rotary machine, there is a steam turbine. This steam turbine generally has a rotor that rotates about an axis, a casing that covers the outer periphery of the rotor, and a plurality of internal components disposed within the casing. Examples of the internal components include a seal ring that faces the outer peripheral surface of the rotor, a seal retaining ring that holds the seal ring, and the like. The casing, the seal ring, and the seal retaining ring each have an upper half portion that is above the axis and a lower half portion that is below the axis.

[0003] In the axial flow rotary machine as described above, it is important to manage the seal clearance, which is the clearance between the seal ring and the rotor.

[0004] Therefore, in Patent Document 1 below, the seal clearance is grasped by the following method. In this Patent Document 1, after disassembling a steam turbine, which is a type of axial flow rotary machine, once, all of the plurality of components that make up this steam turbine, namely, the upper half casing, the lower half casing, the upper half seal ring, the lower half seal ring, the upper half seal retaining ring, the lower half seal retaining ring, and the rotor, are temporarily assembled. In the process of this temporary assembly, a plurality of shims are inserted between the outer periphery of the rotor and the inner peripheral surface of the seal ring, and the seal clearance is obtained from the number of inserted shims.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] In the technology described in Patent Document 1, it is necessary to temporarily assemble the upper casing, lower casing, upper seal ring, lower seal ring, upper seal retaining ring, lower seal retaining ring, and rotor in order to determine the seal clearance.

[0007] Therefore, the technology described in Patent Document 1 requires a great deal of effort to determine the seal clearance.

[0008] Therefore, this disclosure aims to provide a technology that can reduce the effort required to determine seal clearance. [Means for solving the problem]

[0009] A method for estimating the seal clearance of an axial flow rotating machine, as one embodiment for achieving the aforementioned objective, is applicable to the following axial flow rotating machine. This axial flow rotary machine comprises a rotor rotatable about a rotor axis extending horizontally, a casing covering the outer circumference of the rotor, a seal ring forming an annular shape around the rotor axis and positioned on the inner circumference of the casing and the outer circumference of the rotor, and a seal retaining ring forming an annular shape around the rotor axis, attached to the inner circumference of the casing, and holding the seal ring on its own inner circumference. The casing has a semi-circular upper half casing forming the upper part with respect to the rotor axis, and a semi-circular lower half casing forming the lower part with respect to the rotor axis. The seal retaining ring has a semi-circular upper half seal retaining ring forming the upper part with respect to the rotor axis and attached to the upper half casing, and a semi-circular lower half seal retaining ring forming the lower part with respect to the rotor axis and attached to the lower half casing. The seal ring comprises a semi-circular upper seal ring that forms the upper portion with respect to the rotor axis and is held on the inner circumference side of the upper seal retaining ring, and a semi-circular lower seal ring that forms the lower portion with respect to the rotor axis and is held on the inner circumference side of the lower seal retaining ring. The lower seal retaining ring is supported from below by the lower casing and has a support position. The above method for estimating the seal clearance between the seal ring and the rotor in an axial flow rotating machine includes: an upper half retaining ring temporary axis grasping step for grasping the upper half retaining ring temporary axis, which is the temporary central axis of the upper half seal retaining ring in a standalone state; a lower half retaining ring temporary axis grasping step for grasping the lower half retaining ring temporary axis, which is the temporary central axis of the lower half seal retaining ring in a standalone state; an upper half ring temporary radius measuring step for assembling the upper half seal ring into the upper half seal retaining ring and measuring the upper half ring temporary radius, which is the distance from the upper half retaining ring temporary axis to a predetermined position in the circumferential direction relative to the upper half seal ring on the inner peripheral edge of the upper half seal ring; and the lower half seal The lower half seal ring is assembled into the retaining ring, and the lower half ring temporary radius is measured, which is the distance from the temporary axis of the lower half retaining ring to a predetermined position in the circumferential direction relative to the lower half seal ring on the inner peripheral edge of the lower half seal ring; the casing temporary axis is grasped, which is the temporary central axis of the lower half casing; the assembly temporary axis is grasped, which is the temporary central axis of the lower half seal retaining ring assembled into the lower half casing; and the clearance is calculated, which determines the clearance of the upper half seal ring at the predetermined position and the clearance of the lower half seal ring at the predetermined position.In the upper half retaining ring temporary axis grasping process, the lower half retaining ring temporary axis grasping process, the casing temporary axis grasping process, and the assembly temporary axis grasping process, each of the upper half seal retaining ring in its individual state, the lower half seal retaining ring in its individual state, the lower half casing, and the lower half seal retaining ring assembled into the lower half casing are treated as half retaining rings, and each of the upper half retaining ring temporary axis, the lower half retaining ring temporary axis, the casing temporary axis, and the assembly temporary axis are treated as temporary central axes, and in the half retaining ring, at the first cross section, which is the cross section at the first position in the axial direction in which the central axis of the half retaining ring extends, multiple inner surface positions that are different from each other in the circumferential direction with respect to the central axis are measured. The process includes: a first measurement step; a second measurement step of measuring a plurality of inner circumferential surface positions that are different from each other in the circumferential direction with respect to the central axis in a second cross section, which is a cross section at a second position in the semi-holding ring that is different from the first position in the axial direction; and a provisional central axis calculation step of determining a first central position, which is the center position of a first approximate circle that passes through positions close to each of the plurality of inner circumferential surface positions obtained in the first measurement step, and determining a second central position, which is the center position of a second approximate circle that passes through positions close to each of the plurality of inner circumferential surface positions obtained in the second measurement step, and setting a provisional central axis as a straight line connecting the first central position and the second central position. In the clearance calculation step, the amount of axial misalignment, which is the amount of misalignment of the assembled temporary shaft relative to the casing temporary shaft, is determined. The upper half basic clearance is determined by subtracting the rotor radius, which is the radius of the portion of the rotor facing the upper half seal ring, from the upper half ring basic radius, which is the value obtained by adding or subtracting the amount of axial misalignment from the upper half ring temporary radius. Based on the upper half basic clearance, the clearance of the upper half seal ring at the predetermined position is determined. The lower half basic clearance is determined by subtracting the rotor radius, which is the radius of the portion of the rotor facing the lower half seal ring, from the lower half ring basic radius, which is the value obtained by subtracting or adding the amount of axial misalignment from the lower half ring temporary radius. Based on the lower half basic clearance, the clearance of the lower half seal ring at the predetermined position is determined.

[0010] In this embodiment, the clearance between the seal ring and the rotor can be obtained without temporarily assembling the rotor inside the casing, thus reducing the effort required to determine the seal clearance. [Effects of the Invention]

[0011] In one aspect of this disclosure, the effort required to determine the seal clearance of an axial flow rotating machine can be reduced. [Brief explanation of the drawing]

[0012] [Figure 1] This is a cross-sectional view of a steam turbine as an axial-flow rotating machine in one embodiment of the present disclosure. [Figure 2] This is a perspective view of the lower half portion of a steam turbine as an axial flow machine in one embodiment of the present disclosure. [Figure 3] This is a cross-sectional view of the main parts of a high-pressure seal retaining ring, a low-pressure seal retaining ring, and a partition seal retaining ring, and an axial seal ring held by these retaining rings, according to one embodiment of the present disclosure. [Figure 4] This is a cross-sectional view of a blade ring, an axial seal ring held by the blade ring, and a rotor blade row seal ring in one embodiment of the present disclosure. [Figure 5] This flowchart shows the procedure for executing a seal clearance estimation method in one embodiment of the present disclosure. [Figure 6] This flowchart shows the execution procedures for the upper half-holding ring temporary shaft gripping step, the lower half-holding ring temporary shaft gripping step, the casing temporary shaft gripping step, and the assembled temporary shaft gripping step in one embodiment of the present disclosure. [Figure 7] This flowchart shows the procedure for executing the connection status determination step in one embodiment of the present disclosure. [Figure 8] This is an explanatory diagram illustrating the upper half-holding ring temporary axis gripping step and the lower half-holding ring temporary axis gripping step in one embodiment relating to this disclosure. [Figure 9]It is an explanatory diagram for explaining the installation state of the semi-retaining ring during the first measurement process and the installation state of the semi-retaining ring in the second measurement process in one embodiment according to the present disclosure. [Figure 10] It is an explanatory diagram for explaining the upper half ring provisional radius measurement process and the lower half ring provisional radius measurement process in one embodiment according to the present disclosure. [Figure 11] It is an explanatory diagram showing the installation state of the semi-retaining ring during the upper half ring provisional radius measurement process and the installation state of the semi-retaining ring during the lower half ring provisional radius measurement process in one embodiment according to the present disclosure. [Figure 12] It is an explanatory diagram showing the state of measuring the semi-ring provisional radius of the semi-sealing ring incorporated in the semi-wing ring in one embodiment according to the present disclosure with a three-dimensional shape device. [Figure 13] It is an explanatory diagram showing the state of measuring the semi-ring provisional radius of the semi-sealing ring incorporated in the semi-wing ring in the comparative example with a three-dimensional shape device. [Figure 14] It is an explanatory diagram for explaining the support state grasping process in one embodiment according to the present disclosure. [Figure 15] It is an explanatory diagram for explaining the connection state grasping process in one embodiment according to the present disclosure. [Figure 16] It is an explanatory diagram for explaining the casing provisional axis grasping process in one embodiment according to the present disclosure. [Figure 17] It is an explanatory diagram for explaining the incorporated state vertical distance measurement process in one embodiment according to the present disclosure. [Figure 18] It is an explanatory diagram for explaining the incorporated connection state vertical distance measurement process in one embodiment according to the present disclosure. [Figure 19] It is an explanatory diagram showing each clearance in one embodiment according to the present disclosure.

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of a seal clearance estimation method for an axial flow rotating machine according to the present disclosure will be described.

[0014] 「Embodiments of Axial Flow Rotating Machines」 The axial flow rotating machine in this embodiment will be described with reference to Figures 1 to 4.

[0015] The axial-flow rotating machine in this embodiment is a steam turbine, as shown in Figures 1 and 2. This steam turbine comprises a rotor 10 rotatable about a rotor axis Ar, a casing 20 covering the outer circumference of the rotor 10, a plurality of stator blade rows 27, a blade ring 30, a high-pressure seal retaining ring 32, a first low-pressure seal retaining ring 33, and a second low-pressure seal retaining ring 34. Here, the direction in which the rotor axis Ar extends is called the rotor axis direction Da, the circumferential direction relative to the rotor axis Ar is simply called the circumferential direction Dc, and the radial direction relative to the rotor axis Ar is simply called the radial direction Dr. Furthermore, in this radial direction Dr, the side approaching the rotor axis Ar is called the radial inner direction Dri, and the side moving away from the rotor axis Ar is called the radial outer direction Dr. Note that the rotor axis Ar is the axis when the plurality of components constituting the steam turbine are assembled.

[0016] The casing 20 includes a steam expansion chamber 21, a steam inlet 22 for introducing steam into the steam expansion chamber 21, a steam outlet 23 for exhausting steam from the steam expansion chamber 21, a high-pressure side gland bore section 24h, and a low-pressure side gland bore section 24l.

[0017] The steam expansion chamber 21 is an annular space around the rotor 10, extending in the rotor axial direction Da. The steam inlet 22 is formed in the steam expansion chamber 21 so that steam can be introduced into the first side Da1 portion of the two sides in the rotor axial direction Da. The steam outlet 23 is formed in the steam expansion chamber 21 so that steam can be exhausted from the second side Da2 portion in the rotor axial direction Da. Therefore, in the steam expansion chamber 21, in the rotor axial direction Da, the side where the steam inlet 22 is located relative to the steam outlet 23 is the upstream side, and in the rotor axial direction Da, the side where the steam outlet 23 is located relative to the steam inlet 22 is the downstream side. The high-pressure side gland bore section 24h is formed in the casing 20 at the end of the first side Da1 in the rotor axial direction Da. The low-pressure side gland bore section 24l is formed in the casing 20 at the end of the second side Da2 in the rotor axial direction Da. Both the high-pressure side gland bore section 24h and the low-pressure side gland bore section 24l have an annular inner circumferential surface around the rotor axis Ar.

[0018] The casing 20 comprises an upper casing 20u and a lower casing 20l. The upper casing 20u forms the upper part of the casing 20 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular. The lower casing 20l forms the lower part of the casing 20 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular.

[0019] The rotor 10 has a rotor shaft portion 11 extending in the direction of the rotor axis Da with respect to the rotor axis Ar, and a plurality of rotor blade rows 12 provided on the rotor shaft portion 11. The plurality of rotor blade rows 12 are arranged in the direction of the rotor axis Da within the steam expansion chamber 21. Each of the plurality of rotor blade rows 12 has a plurality of rotor blades arranged in the circumferential direction Dc. The plurality of stator blade rows 27 are arranged in the direction of the rotor axis Da within the steam expansion chamber 21. Upstream of each plurality of rotor blade rows 12, one of the plurality of stator blade rows 27 within the steam expansion chamber 21 is located.

[0020] The wing ring 30 is located inside the casing 20. Multiple rows of stator blades 27 are attached to this wing ring 30.

[0021] The blade ring 30 comprises an upper blade ring 30u and a lower blade ring 30l. The upper blade ring 30u forms the upper part of the blade ring 30 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular. This upper blade ring 30u is located within the upper casing 20u. The lower blade ring 30l forms the lower part of the blade ring 30 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular. This lower blade ring 30l is located within the lower casing 20l.

[0022] The high-pressure seal retaining ring 32 is located in the casing 20 at the high-pressure side gland bore portion 24h in the rotor axial direction Da. The first low-pressure seal retaining ring 33 is located in the casing 20 between the low-pressure side gland bore portion 24l and the steam outlet 23 in the rotor axial direction Da. The second low-pressure seal retaining ring 34 is located at the low-pressure side gland bore portion 24l in the rotor axial direction Da. The high-pressure seal retaining ring 32, the first low-pressure seal retaining ring 33, and the second low-pressure seal retaining ring 34 are all annular around the rotor axis Ar.

[0023] The high-pressure seal retaining ring 32, the first low-pressure seal retaining ring 33, and the second low-pressure seal retaining ring 34 all hold a plurality of shaft seal rings 36 on their inner circumference, as shown in Figure 3. Each shaft seal ring 36 faces the rotor shaft portion 11 with a small gap in the radial direction Dr. Each shaft seal ring 36 has the function of suppressing the steam flow in the rotor axial direction Da.

[0024] As shown in Figures 1 and 3, the high-pressure seal retaining ring 32, the first low-pressure seal retaining ring 33, and the second low-pressure seal retaining ring 34 each have an upper seal retaining ring 35u and a lower seal retaining ring 35l. The upper seal retaining ring 35u forms the upper part of each seal retaining ring 32, 33, and 34 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular. This upper seal retaining ring 35u is located within the upper casing 20u. The lower seal retaining ring 35l forms the lower part of each seal retaining ring 32, 33, and 34 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular. This lower seal retaining ring 35l is located within the lower casing 20l.

[0025] The multiple shaft seal rings 36 held on the inner circumference side of the high-pressure seal retaining ring 32, the first low-pressure seal retaining ring 33, and the second low-pressure seal retaining ring 34 each have an upper seal ring 38u and a lower seal ring 38l. The upper seal ring 38u forms the upper part of the shaft seal ring 36 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular. This upper seal ring 38u is held on the inner circumference side of the upper seal retaining ring 35u. The lower seal ring 38l forms the lower part of the shaft seal ring 36 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular. This lower seal ring 38l is held on the inner circumference side of the lower seal retaining ring 35l.

[0026] As shown in Figure 4, each of the multiple rotor blades 13 constituting the rotor blade row 12 has an airfoil cross-section and comprises a blade body 13b extending in the radial direction Dr, and a blade root 13r provided on the radially inward Dri of the blade body 13b. The rotor blade 13 is attached to the rotor shaft 11 by having its blade root 13r fitted into the rotor shaft 11. Each of the multiple stator blades 28 constituting the stator blade row 27 has an airfoil cross-section and comprises a blade body 28b extending in the radial direction Dr, an inner shroud 28i provided on the radially inward Dri of the blade body 28b, and an outer shroud 28o provided on the radially outward Dro of the blade body 28b. The stator blade 28 is attached to the blade ring 30 by having its outer shroud 28o fitted into the blade ring 30.

[0027] Within the blade ring 30, a rotor blade row seal ring 37 is held in the portion facing each of the multiple rotor blade rows 12 in the radial direction Dr. Each rotor blade row seal ring 37 has a small gap in the radial direction Dr with respect to the opposing rotor blade row 12. An axial seal ring 36 is attached to the inner shroud 28i of each of the multiple stator blade rows 27. Each axial seal ring 36 faces the rotor shaft portion 11 with a small gap in the radial direction Dr. Therefore, the blade ring 30 also functions as a seal retaining ring that holds the multiple rotor blade row seal rings 37 and the multiple axial seal rings 36 on its inner circumference. Each rotor blade row seal ring 37 and each axial seal ring 36 have the function of suppressing the steam flow in the rotor axial direction Da.

[0028] Each rotor blade row seal ring 37 and each shaft seal ring 36 each have an upper seal ring 38u and a lower seal ring 38l. The upper seal ring 38u forms the upper part of the seal rings 36 and 37 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular. This upper seal ring 38u is held on the inner circumference side of the upper blade ring 30u. The lower seal ring 38l forms the lower part of the seal rings 36 and 37 with respect to the rotor axis Ar, and its cross-section perpendicular to the rotor axis Ar is semi-circular. This lower seal ring 38l is held on the inner circumference side of the lower blade ring 30l.

[0029] The lower half seal retaining rings 35l of the high-pressure seal retaining ring 32, the first low-pressure seal retaining ring 33, and the second low-pressure seal retaining ring 34, as well as the lower half wing ring 30l, have flanges 35f that protrude horizontally and radially outward Dro, as shown in Figure 2. The lower surface of these flanges 35f forms a support position 35s (see Figure 18) where the lower half casing 20l supports the above rings from below.

[0030] "Embodiment of a method for estimating seal clearance" The seal clearance, which is the radial clearance Dr between the multiple shaft seal rings 36 and the rotor shaft portion 11 of the rotor 10, and the radial clearance Dr between the multiple rotor blade row seal rings 37 and the rotor blade row 12 of the rotor 10, is an important factor in managing the performance of a steam turbine. Therefore, one embodiment of the seal clearance estimation method will be described below according to the flowchart shown in Figures 5 to 7.

[0031] Here, to simplify the explanation of the seal clearance estimation method, the high-pressure seal retaining ring 32, the first low-pressure seal retaining ring 33, the second low-pressure seal retaining ring 34, and the blade ring 30 are referred to as the seal retaining ring 40. The upper half seal retaining ring 35u of the high-pressure seal retaining ring 32, the upper half seal retaining ring 35u of the first low-pressure seal retaining ring 33, the upper half seal retaining ring 35u of the second low-pressure seal retaining ring 34, and the upper half blade ring 30u of the blade ring 30 are referred to as the upper half seal retaining ring 40u. The lower half seal retaining ring 35l of the high-pressure seal retaining ring 32, the lower half seal retaining ring 35l of the first low-pressure seal retaining ring 33, the lower half seal retaining ring 35l of the second low-pressure seal retaining ring 34, and the lower half blade ring 30l of the blade ring 30 are referred to as the lower half seal retaining ring 40l. The shaft seal ring 36 and the rotor blade row seal ring 37 are simply referred to as the seal ring 45. The upper seal ring 38u of the shaft seal ring 36 and the upper seal ring 38u of the rotor blade row seal ring 37 are simply referred to as the upper seal ring 45u. The lower seal ring 38l of the shaft seal ring 36 and the lower seal ring 38l of the rotor blade row seal ring 37 are simply referred to as the lower seal ring 45l.

[0032] In the seal clearance estimation method of this embodiment, as shown in the flowchart of Figure 5, first, the upper half-holding ring temporary axis grasping step S1 and the lower half-holding ring temporary axis grasping step S2 are performed. Note that either the upper half-holding ring temporary axis grasping step S1 or the lower half-holding ring temporary axis grasping step S2 may be performed first.

[0033] As shown in Figure 8, in the upper half retaining ring temporary axis grasping step S1, the temporary axis Ah of the upper half seal retaining ring 40u in its standalone state, which is the upper half retaining ring temporary axis Ahu, is grasped. In the lower half retaining ring temporary axis grasping step S2, the temporary axis Ah of the lower half seal retaining ring 40l in its standalone state, which is the lower half retaining ring temporary axis Ahl, is grasped.

[0034] In the upper half-retaining ring temporary axis gripping step S1, as shown in Figure 9, the upper half-seal retaining ring 40u is placed on the work surface as a single unit so that the central axis Arc of the semicircular arc in the upper half-seal retaining ring 40u extends in the vertical direction Dv. The upper half-retaining ring temporary axis Ahu gripped in the upper half-retaining ring temporary axis gripping step S1 is approximately coincident with the central axis Arc of the upper half-seal retaining ring 40u, but is not necessarily a perfect coincidence. Similarly, in the lower half-retaining ring temporary axis gripping step S2, the lower half-seal retaining ring 40l is placed on the work surface as a single unit so that the central axis Arc of the semicircular arc in the lower half-seal retaining ring 40l extends in the vertical direction Dv. The lower half-retaining ring temporary axis Ahl gripped in the lower half-retaining ring temporary axis gripping step S2 is approximately coincident with the central axis Arc of the lower half-seal retaining ring 40l, but is not necessarily a perfect coincidence.

[0035] Here, the semi-circular upper seal retaining ring 40u and the semi-circular lower seal retaining ring 40l are referred to as the semi-retaining ring 40h. Furthermore, the temporary upper retaining ring axis Ahu of the upper seal retaining ring 40u in its standalone state and the temporary lower retaining ring axis Ahl of the lower seal retaining ring 40l in its standalone state are referred to as the temporary central axis Ah.

[0036] In the upper half-holding ring temporary axis grasping process S1 and the lower half-holding ring temporary axis grasping process S2, the first measurement process S21, the second measurement process S22, and the temporary center axis calculation process S23 are performed, as shown in the flowchart in Figure 6.

[0037] In the first measurement step S21, as shown in Figure 9, multiple distinct inner surface positions Ph1 are measured in the circumferential direction Dch with respect to the central axis Arc of the semi-retaining ring 40h at the first cross-section, which is the cross-section at the first position in the axial direction along which the central axis Arc of the semi-retaining ring 40h extends. In the second measurement step S22, multiple distinct inner surface positions Ph2 are measured in the circumferential direction Dch with respect to the central axis Arc at the second cross-section, which is the cross-section at a second position different from the first position in the axial direction of the semi-retaining ring 40h.

[0038] When measuring multiple inner surface positions, a three-dimensional measuring device 50 is used. The three-dimensional measuring device 50 used in this embodiment has, for example, a laser tracker that irradiates a target with laser light, receives the laser light reflected from the target, and measures the three-dimensional position of the target.

[0039] In the provisional central axis calculation step S23, the first central position Cc1 is determined, which is the center position of the approximate circle CA1 that passes through positions close to each of the multiple inner surface positions Ph1 obtained in the first measurement step S21. At the same time, the second central position Cc2 is determined, which is the center position of the approximate circle CA2 that passes through positions close to each of the multiple inner surface positions Ph2 obtained in the second measurement step S22. The approximate circles CA1 and CA2 may pass through any of the multiple inner surface positions Ph1 and Ph2. Then, in this provisional central axis calculation step S23, the line connecting the first central position Cc1 and the second central position Cc2 is defined as the provisional central axis Ah, and the position of this provisional central axis Ah is determined.

[0040] As described above, in the temporary central axis calculation step S23 of the temporary axis grasping step S1 of the upper half-holding ring, the position of the temporary central axis Ah, which is the temporary axis Ahu of the upper half-holding ring, is determined, and in the temporary central axis calculation step S23 of the temporary axis grasping step S2 of the lower half-holding ring, the position of the temporary central axis Ah, which is the temporary axis Ahl of the lower half-holding ring, is determined.

[0041] Next, as shown in the flowchart of Figure 5, the temporary radius measurement process S3 for the upper ring and the temporary radius measurement process S4 for the lower ring are performed. Note that either the temporary radius measurement process S3 for the upper ring or the temporary radius measurement process S4 for the lower ring may be performed first. Also, the temporary radius measurement process S3 for the upper ring may be performed before the temporary axis gripping process S2 for the lower ring, provided it is performed after the temporary axis gripping process S1 for the upper ring. Furthermore, the temporary radius measurement process S4 for the lower ring may be performed before the temporary axis gripping process S1 for the lower ring, provided it is performed after the temporary axis gripping process S2 for the lower ring.

[0042] As shown in Figure 10, in the upper half-ring temporary radius measurement process S3, the upper half-seal ring 45u is assembled into the upper half-seal retaining ring 40u, and the upper half-ring temporary radius rst is measured, which is the distance from the upper half-retaining ring temporary axis Ahu to a predetermined position in the circumferential direction Dcs with respect to the upper half-seal ring 45u on the inner circumference of the upper half-seal ring 45u. Here, the predetermined position in the circumferential direction Dcs with respect to the upper half-seal ring 45u on the inner circumference of the upper half-seal ring 45u is the central position in the circumferential direction Dcs with respect to the upper half-seal ring 45u on the inner circumference of the upper half-seal ring 45u. When the multiple components constituting the steam turbine are assembled, the central position in the circumferential direction Dcs with respect to the upper half-seal ring 45u is the position vertically above the rotor axis Ar on the inner circumference of the upper half-seal ring 45u. For this reason, the upper half-ring temporary radius measured in the upper half-ring temporary radius measurement process S3 may be referred to as the ring top temporary radius rst below.

[0043] In the lower half-ring temporary radius measurement process S4, the lower half-seal ring 45l is assembled into the lower half-seal retaining ring 40l, and the lower half-ring temporary radii rsb, rsl, and rsr are measured, which are the distances from the lower half-retaining ring temporary axis Ahl to predetermined positions in the circumferential direction Dcs with respect to the lower half-seal ring 45l within the inner circumference of the lower half-seal ring 45l. Here, the predetermined positions in the circumferential direction Dcs with respect to the lower half-seal ring 45l within the inner circumference of the lower half-seal ring 45l include the central position in the circumferential direction Dcs with respect to the lower half-seal ring 45l within the inner circumference of the lower half-seal ring 45l, and the first end position and the second end position, which are the positions at both ends of the circumferential direction Dcs with respect to the lower half-seal ring 45l within the inner circumference of the lower half-seal ring 45l. The central position in the circumferential direction Dcs with respect to the lower half-seal ring 45l is the position vertically below the rotor axis Ar within the inner circumference of the lower half-seal ring 45l when the multiple components constituting the steam turbine are assembled. Therefore, in the following, among the three lower half-ring temporary radii rsb, rsl, and rsr measured in the lower half-ring temporary radius measurement process S4, the distance from the lower half-holding ring temporary shaft Ahl to the center position in the circumferential direction Dcs with respect to the lower half-seal ring 45l within the inner circumference of the lower half-seal ring 45l may be referred to as the ring bottom temporary radius rsb. The first end position in the circumferential direction Dcs with respect to the lower half-seal ring 45l is, when the multiple components constituting the steam turbine are assembled, the position to the left of the rotor axis Ar within the inner circumference of the lower half-seal ring 45l. Therefore, in the following, among the three lower half-ring temporary radii rsb, rsl, and rsr measured in the lower half-ring temporary radius measurement process S4, the distance from the lower half-holding ring temporary shaft Ahl to the first end position in the circumferential direction Dcs with respect to the lower half-seal ring 45l within the inner circumference of the lower half-seal ring 45l may be referred to as the ring left temporary radius rsl. The second end position of the circumferential Dcs with respect to the lower seal ring 45l is located to the right horizontally with respect to the rotor axis Ar within the inner circumferential edge of the lower seal ring 45l when the multiple components constituting the steam turbine are assembled.Therefore, in the following, among the three lower half ring temporary radii rsb, rsl, and rsr measured in the lower half ring temporary radius measurement process S4, the distance from the lower half holding ring temporary axis Ahl to the second end position in the circumferential direction Dcs with respect to the lower half seal ring 45l within the inner circumference of the lower half seal ring 45l may be referred to as the ring right temporary radius rsr.

[0044] In the upper half-ring temporary radius measurement process S3 and the lower half-ring temporary radius measurement process S4, as shown in Figure 11, the semi-retaining ring 40h is placed on the work area in a single unit state so that its central axis Arc extends in the vertical direction Dv, similar to the upper half-retaining ring temporary axis gripping process S1 and the lower half-retaining ring temporary axis gripping process S2. That is, the upper half-ring temporary radius measurement process S3 is performed while the installation state of the semi-retaining ring 40h in the upper half-retaining ring temporary axis gripping process S1 is maintained, and the lower half-ring temporary radius measurement process S4 is performed while the installation state of the semi-retaining ring 40h in the lower half-retaining ring temporary axis gripping process S2 is maintained.

[0045] In the upper half-ring temporary radius measurement process S3 and the lower half-ring temporary radius measurement process S4, the upper half-seal ring 45u or the lower half-seal ring 45l, which is the half-seal ring 45h, is incorporated into the half-retaining ring 40h in the above-described installation state. Next, the predetermined position in the circumferential direction Dcs relative to the half-seal ring 45h is measured using the three-dimensional measuring device 50 described above. Then, the distance from the temporary central axis Ah, which is the temporary axis Ahu of the upper half-retaining ring or the temporary axis Ahl of the lower half-retaining ring, to the predetermined position is determined, and these distances are defined as the upper half-ring temporary radius rst or the lower half-ring temporary radii rsb, rsl, rsr.

[0046] If the semi-retaining ring 40h is the upper half-wing ring 30u, in the upper half-ring temporary radius measurement process S3, the upper half-seal rings 38u of the multiple rotor blade row seal rings 37 and the multiple stator blades 28 are attached to the upper half-wing ring 30u. Furthermore, in this upper half-ring temporary radius measurement process S3, the upper half-seal ring 38u of the shaft seal ring 36 is attached to the multiple stator blades 28 that are already attached to the upper half-wing ring 30u. Also, if the semi-retaining ring 40h is the lower half-wing ring 30l, in the lower half-ring temporary radius measurement process S4, the lower half-seal rings 38l of the multiple rotor blade row seal rings 37 and the multiple stator blades 28 are attached to the lower half-wing ring 30l. Furthermore, in this lower half-ring temporary radius measurement process S4, the lower half-seal ring 38l of the shaft seal ring 36 is attached to the multiple stator blades 28 that are already attached to the lower half-wing ring 30l.

[0047] Suppose, as shown in Figure 13, the upper half-wing ring 30u or lower half-wing ring 30l, which is the semi-retaining ring 40h, is placed on the work site so that the central axis Arc of the semi-circular arc of the upper half-wing ring 30u or lower half-wing ring 30l extends in the horizontal direction Dh, and the semi-ring temporary radius measurement process S3,4 is performed. In this case, if the three-dimensional measuring device 50 is to be placed in a position opposite the inner circumferential surface of the semi-retaining ring 40h, that is, above the semi-retaining ring 40h, a special support jig to support the three-dimensional measuring device 50 will be required, increasing the cost of executing the seal clearance estimation method. Therefore, it is conceivable to place the three-dimensional measuring device 50 on one side and the other side in the axial direction in which the central axis Arc extends, using the semi-wing ring 30 as a reference. Thus, when the three-dimensional measuring device 50 is positioned, the position of the inner edge of the rotor blade row seal ring 37 on the half-seal rings 38u and 38l, which is located further from the three-dimensional measuring device 50 in the axial direction (horizontal direction) than the multiple stator vanes 28 attached to the semi-retaining ring 40h, cannot be measured by the three-dimensional measuring device 50.

[0048] On the other hand, in this embodiment, as shown in Figure 12, the semi-retaining ring 40h, which is the upper semi-wing ring 30u or the lower semi-wing ring 30l, is placed on the work surface so that the central axis Arc of the semi-circular arc of the semi-circular ring 40h, which is the upper semi-wing ring 30u or the lower semi-wing ring 30l, extends in the vertical direction Dv, and the semi-ring temporary radius measurement process S3,4 is performed. In this case, the three-dimensional measuring device 50 can be easily positioned opposite the inner circumferential surface of the semi-retaining ring 40h. In this case, by moving the three-dimensional measuring device 50 up and down at the position opposite the inner circumferential surface of the semi-retaining ring 40h, the positions of the inner circumferential edges of the semi-seal rings 38u, 38l of all the rotor blade row seal rings 37 attached to the semi-retaining ring 40h, and the positions of the inner circumferential edges of the semi-seal rings 38u, 38l of all the shaft seal rings 36 attached to the semi-retaining ring 40h can be measured by the three-dimensional measuring device 50.

[0049] Therefore, it is preferable to perform the upper half-ring temporary radius measurement step S3 and the lower half-ring temporary radius measurement step S4 on the semi-retaining ring 40h in a state where the central axis Arc of the semi-circular arc extends in the vertical direction Dv. Furthermore, it is preferable to perform the first measurement step S21 and the second measurement step S22 in the upper half-retaining ring temporary axis gripping step S1 and the lower half-retaining ring temporary axis gripping step S2 on the semi-retaining ring 40h in a state where the central axis Arc of the semi-circular arc extends in the vertical direction Dv. This is because the upper half-ring temporary radius measurement step S3 and the lower half-ring temporary radius measurement step S4 can be performed after the upper half-retaining ring temporary axis gripping step S1 and the lower half-retaining ring temporary axis gripping step S2 without changing the installation state of the semi-retaining ring 40h.

[0050] Next, as shown in the flowchart of Figure 5, the support state determination step S5 is performed. In this support state determination step S5, as shown in Figure 14, the temporary radius of the lower seal retaining ring 40l, which is the temporary radius of the lower seal retaining ring 40l, and the vertical distance hb of the support state are determined when the lower seal retaining ring 40l is supported from below at the support position 35s, is not connected to the upper seal retaining ring 40u, and the lower seal ring 45l is not incorporated.

[0051] Next, as shown in the flowchart of Figure 5, the connection state determination step S6 is performed. In this connection state determination step S6, as shown in Figure 15, the connection state temporary radius rc, which is the temporary radius of the lower half seal retaining ring 40l, and the connection state vertical distance hc are determined when the lower half seal retaining ring 40l is supported from below at the support position 35s and connected to the upper half seal retaining ring 40u, and the lower half seal ring 45l is not incorporated.

[0052] The details of the support state determination process S5 and the connection state determination process S6 will now be explained. In the connection state determination process S6, the measurement process S31 and the approximate circle setting process S32 are performed as shown in Figure 7.

[0053] Here, the lower half seal retaining ring 40l in the state where it is supported from below at support position 35s, is not connected to the upper half seal retaining ring 40u, and the lower half seal retaining ring 45l is not incorporated, and the lower half seal retaining ring 40l in the state where it is supported from below at support position 35s, is connected to the upper half seal retaining ring 40u, and the lower half seal retaining ring 45l is not incorporated, are defined as the specific state semi-retaining ring 46. Furthermore, the temporary radius rb in the support state and the temporary radius rc in the connected state are defined as the temporary radius rh in the specific state.

[0054] In the support state determination step S5, as shown in Figure 14, the radius of the first approximate circle CA1 or the second approximate circle CA2 obtained in the lower half-holding ring temporary axis determination step S2 is set to the specific state temporary radius rh, or in other words, the support state temporary radius rb. Furthermore, the support state vertical distance hb is determined, which is the vertical distance Dv between the center Ahl of the first approximate circle CA1 or the second approximate circle CA2 and the support position 35s. Here, the first approximate circle CA1 or the second approximate circle CA2 is the approximate circle at the position where the lower half-seal ring 45l is attached in the specific state semi-holding ring 46, in the axial direction in which the central axis of the specific state semi-holding ring 46 extends.

[0055] In the measurement step S31 of the connection state determination step S6, as shown in Figure 15, multiple inner circumferential surface positions Phs are measured in the specific state semi-holding ring 46 at positions where the lower half-seal ring 45l and the upper half-seal ring 45u are attached in the axial direction in which the central axis of the specific state semi-holding ring 46 extends, and where they are different in the circumferential direction Dch. In the approximate circle setting step S32 of the connection state determination step S6, an approximate circle CAs is determined that passes through positions close to each of the multiple inner circumferential surface positions Phs obtained in the measurement step S31. The radius of this approximate circle CAs is then defined as the specific state temporary radius rh, or in other words, the connection state temporary radius rc. Furthermore, the connection state vertical distance hc, which is the vertical distance Dv between the center of this approximate circle CAs and the support position 35s, is determined. Note that in the above, only one approximate circle is used in the support state determination step S5 and the connection state determination step S6, but two or more approximate circles may be used. In this case, it is desirable to use two or more approximate circles to determine the temporary radius rh (i.e., rb, rc) for a specific state. In the case of structural components with length in the axial direction Da, such as airfoil rings, the temporary radius rh for a specific state may not be uniform in the axial direction Da. By setting approximate circles for two or more cross-sections and obtaining the temporary radius rh for a specific state, the accuracy of clearance calculation can be improved.

[0056] Next, as shown in the flowchart of Figure 5, the casing temporary axis grasping process S7 is performed. In this casing temporary axis grasping process S7, as shown in Figure 16, the casing temporary axis Ac, which is the temporary central axis of the lower half casing 20l, is grasped. In this casing temporary axis grasping process S7, as shown in the flowchart of Figure 6, the first measurement process S21, the second measurement process S22, and the temporary central axis calculation process S23 are also performed.

[0057] In the first measurement step S21 of the casing temporary axis gripping step S7, as shown in Figure 9, in the semi-retaining ring 40h, which is the lower half casing 20l, multiple different inner surface positions Ph1 are measured in the circumferential direction Dch with respect to the central axis Arc at the first cross-section, which is the cross-section at the first position in the axial direction in which the central axis Arc of the semi-retaining ring 40h extends. In the second measurement step S22, multiple different inner surface positions Ph2 are measured in the circumferential direction Dch with respect to the central axis Arc at the second cross-section, which is the cross-section at the second position in the semi-retaining ring 40h, which is different from the first position in the axial direction. Note that the first cross-section here is the cross-section of the high-pressure side ground bore portion 24h of the lower half casing 20l, as shown in Figure 2, and the second cross-section is the cross-section of the low-pressure side ground bore portion 24l of the lower half casing 20l.

[0058] In the temporary central axis calculation step S23 of the casing temporary axis grasping step S7, as shown in Figures 9 and 16, the first central position Cc1 is determined, which is the center position of the approximate circle CA1 that passes through positions close to each of the multiple inner surface positions Ph1 obtained in the first measurement step S21, and the second central position Cc2 is determined, which is the center position of the approximate circle CA2 that passes through positions close to each of the multiple inner surface positions Ph2 obtained in the second measurement step S22. The approximate circles CA1 and CA2 may pass through any of the multiple inner surface positions Ph1 and Ph2. Then, in this temporary central axis calculation step S23, the temporary central axis Ah, which is the casing temporary axis Ac, is determined based on the straight line connecting the first central position Cc1 and the second central position Cc1.

[0059] Next, as shown in the flowchart of Figure 5, the temporary shaft assembly and grasping process S8 is performed. In this temporary shaft assembly and grasping process S8, as shown in Figure 17, the temporary shaft Ahc, which is the temporary center axis Ah of the lower seal retaining ring 40l assembled in the lower casing 20l, is grasped. In this temporary shaft assembly and grasping process, as shown in the flowchart of Figure 6, the first measurement process S21, the second measurement process S22, and the temporary center axis calculation process S23 are also performed.

[0060] In the first measurement step S21 of the assembly temporary shaft gripping step S8, as shown in Figure 9, in the semi-retaining ring 40h, which is the lower half seal retaining ring 40l incorporated into the lower half casing 20l, multiple different inner surface positions Ph1 are measured in the circumferential direction Dch with respect to the central axis Arc at the first cross-section, which is the cross-section at the first position in the axial direction in which the central axis Arc of the semi-retaining ring 40h extends. In the second measurement step S22, multiple different inner surface positions Ph2 are measured in the circumferential direction Dch with respect to the central axis Arc at the second cross-section, which is the cross-section at the second position in the semi-retaining ring 40h, which is different from the first position in the axial direction.

[0061] In the temporary central axis calculation step S23 of the temporary shaft acquisition step S8, the first central position Cc1 is determined, which is the center position of the approximate circle CA1 that passes through positions close to each of the multiple inner surface positions Ph1 obtained in the first measurement step S21. At the same time, the second central position Cc2 is determined, which is the center position of the approximate circle CA2 that passes through positions close to each of the multiple inner surface positions Ph2 obtained in the second measurement step S22. The approximate circles CA1 and CA2 may pass through any of the multiple inner surface positions Ph1 and Ph2. Then, in this temporary central axis calculation step S23, the straight line connecting the first central position Cc1 and the second central position Cc2 is defined as the temporary central axis Ah, which is the temporary shaft Ahc.

[0062] Next, as shown in the flowchart of Figure 5, the assembled vertical distance measurement process S9 is performed. In this assembled vertical distance measurement process S9, as shown in Figure 17, with the upper casing 20u not connected to the lower casing 20l, the assembled vertical distance Hb is measured, which is the vertical distance Dv between the casing temporary axis Ac and the support position 35s of the lower seal retaining ring 40l, which is supported from below by the lower casing 20l.

[0063] Next, as shown in the flowchart of Figure 5, the embedded connection state vertical distance measurement process S10 is performed. In this embedded connection state vertical distance measurement process S10, as shown in Figure 18, with the upper half casing 20u connected to the lower half casing 20l, the embedded connection state vertical distance Hc is measured, which is the vertical distance Dv between the casing temporary axis Ac and the support position 35s of the lower half seal retaining ring 40l, which is supported from below by the lower half casing 20l.

[0064] Next, the clearance calculation process S11 is performed as shown in the flowchart of Figure 5.

[0065] In the clearance calculation step S11, the clearance between a predetermined position of the upper seal ring 45u and the rotor 10, and the clearance between a predetermined position of the lower seal ring 45l and the rotor 10 are determined. The predetermined position of the upper seal ring 45u is, as previously described using Figure 10, the position vertically above the rotor axis Ar within the inner circumference of the upper seal ring 45u when the multiple components constituting the steam turbine are assembled. Therefore, in the clearance calculation step S11, the top clearance Ct between the seal ring 45 and the rotor 10 is determined, as shown in Figure 19. The predetermined positions of the lower seal ring 45l are, as previously described using Figure 10, the position vertically below the rotor axis Ar within the inner circumference of the lower seal ring 45l, the position horizontally to the left of the rotor axis Ar within the inner circumference of the lower seal ring 45l, and the position horizontally to the right of the rotor axis Ar within the inner circumference of the lower seal ring 45l when the multiple components constituting the steam turbine are assembled. Therefore, in the clearance calculation step S11, as shown in Figure 19, the bottom clearance Cb, left-side clearance Cl, and right-side clearance Cr between the seal ring 45 and the rotor 10 are further determined.

[0066] In the clearance calculation step S11, the rotor radius R, which is the radius of the portion of the rotor 10 facing the seal ring 45 in the rotor axial direction Da, and the rotor deflection d in the vertical direction Dv in the same portion are obtained in advance.

[0067] In addition, in the clearance calculation process S11, the vertical axis misalignment (axis misalignment) Ecv, the horizontal axis misalignment (axis misalignment) Ech, the radial deformation Δr, the axis displacement Δh, and the casing displacement ΔH are determined.

[0068] The vertical axis misalignment (axis misalignment) Ecv is the value obtained by subtracting the coordinate value Ahcv of the assembled temporary shaft Ahc, obtained in the assembled temporary shaft gripping process S8, from the coordinate value Acv of the casing temporary shaft Ac, obtained in the casing temporary shaft gripping process S7, as shown in Figure 17. Ecv = Acv - Ahcv

[0069] The horizontal axis misalignment (axis misalignment) Ech is the value obtained by subtracting the horizontal coordinate value Ahch of the assembled temporary shaft Ahc, obtained in the assembled temporary shaft gripping process S8, from the horizontal coordinate value Ach of the casing temporary shaft Ac, obtained in the casing temporary shaft gripping process S7, as shown in Figure 17. Ech=Ach-Ahch

[0070] The radial deformation amount Δr is the value obtained by subtracting the temporary support state radius rb, determined in the support state determination step S5, from the temporary connection state radius rc, determined in the connection state determination step S6. The temporary support state radius rb is the radius of the approximate circle CA1 or CA2, determined in the temporary axis determination step S2 of the lower half-holding ring. Δr = rc - rb

[0071] The axial displacement Δh is the value obtained by subtracting the vertical support distance hb obtained in the support state determination process S5 from the vertical connection distance hc obtained in the connection state determination process S6. Δh = hc - hb

[0072] The casing displacement ΔH is the value obtained by subtracting the vertical distance Hb measured in the vertical distance measurement process S9 (see Figure 17) from the vertical distance Hc measured in the vertical distance measurement process S10 (see Figure 18). ΔH = Hc - Hb

[0073] In the clearance calculation step S11, as shown in the following formula, the top clearance Ct is obtained by adding or subtracting the vertical axis misalignment amount Ecv, radius change amount Δr, axis change amount Δh, and casing displacement amount ΔH to the ring top temporary radius rst measured in the upper half ring temporary radius measurement step S3, subtracting the rotor radius R, and then adding the rotor deflection amount d. Ct=[rst-Ecv+Δr+Δh+ΔH]-R+d

[0074] In the above formula, the vertical axis misalignment Ecv is subtracted from the temporary radius rst of the ring top because, in this case, the vertical axis misalignment Ecv (=Acv-Ahcv) is a positive value. On the other hand, if the vertical axis misalignment Ecv (=Acv-Ahcv) is a negative value, the vertical axis misalignment Ecv will be added to the temporary radius rst of the ring top. Also, in the above formula, the radius change Δr (=rc-rb) is added to the temporary radius rst of the ring top. If the radius change Δr is defined as the value obtained by subtracting the connection state temporary radius rc from the support state temporary radius rb (rb-rc), then the radius change Δr will be subtracted from the temporary radius rst of the ring top. Furthermore, in the above formula, the axial displacement Δh is added to the temporary radius rst of the ring top because, in this case, the axial displacement Δh (=hc-hb) is a positive value. On the other hand, if the axial displacement Δh (=hc-hb) is a negative value, the axial displacement Δh is subtracted from the temporary radius of the ring top rst. Also, in the above formula, the casing displacement ΔH is subtracted from the temporary radius of the ring top rst because the casing displacement ΔH (=Hc-Hb) is a positive value in this case. On the other hand, if the casing displacement ΔH (=Hc-Hb) is a negative value, the casing displacement ΔH is added to the temporary radius of the ring top rst.

[0075] As described above, whether to add or subtract the vertical axis displacement Ecv, radius change Δr, axis change Δh, and casing displacement ΔH from the temporary ring top radius rst depends on whether these values ​​are positive or negative, and further, on the definitions of these values.

[0076] Furthermore, the value obtained by adding or subtracting the vertical axis misalignment amount Ecv from the ring top temporary radius rst in the above formula is the upper half ring basic radius (rst±Ecv). Also, the value obtained by subtracting the rotor radius R from this upper half ring basic radius (rst±Ecv) is the upper half basic clearance (rst±Ecv-R).

[0077] In the clearance calculation step S11, as shown in the following formula, the rotor radius R is subtracted from the value obtained by adding or subtracting the vertical axis misalignment Ecv, radius change Δr, axis change Δh, and casing displacement ΔH to the ring bottom temporary radius rsb measured in the lower half ring temporary radius measurement step S4, and then the rotor deflection d is subtracted to obtain the bottom clearance Cb. Cb=[rsb+Ecv+Δr-Δh-ΔH]-Rd

[0078] In the above formula, the vertical axis displacement Ecv is added to the temporary radius rsb of the ring bottom because, in this case, the vertical axis displacement Ecv (=Acv-Ahcv) is a positive value. On the other hand, if the vertical axis displacement Ecv (=Acv-Ahcv) is a negative value, then the vertical axis displacement Ecv is subtracted from the temporary radius rsb of the ring bottom. That is, when calculating the top clearance Ct, the vertical axis displacement Ecv is subtracted, and when calculating the bottom clearance Ct, this vertical axis displacement Ecv is added. Also, in the above formula, the axis displacement Δh is subtracted from the temporary radius rsb of the ring bottom because, in this case, the axis displacement Δh (=hc-hb) is a positive value. On the other hand, if the axis displacement Δh (=hc-hb) is a negative value, then the axis displacement Δh is added to the temporary radius rsb of the ring bottom. In other words, when calculating the top clearance Ct, if the axial displacement Δh is subtracted, then when calculating the bottom clearance Ct, this axial displacement Δh is added. Also, in the above formula, the casing displacement ΔH is added to the temporary radius of the ring bottom rsbrbt because the casing displacement ΔH (=Hc-Hb) is a positive value here. On the other hand, if the casing displacement ΔH (=Hc-Hb) is a negative value, then the casing displacement ΔH is subtracted from the temporary radius of the ring bottom rsb. In other words, when calculating the top clearance Ct, if the casing displacement ΔH is subtracted, then when calculating the bottom clearance Ct, this casing displacement ΔH is added.

[0079] As described above, whether to add or subtract the vertical axial displacement Ecv, radius change Δr, axial change Δh, and casing displacement ΔH from the temporary ring bottom radius rsb depends on whether these values ​​are positive or negative, and further, on the definitions of these values.

[0080] Furthermore, the value obtained by adding or subtracting the vertical axis misalignment amount Ecv from the ring bottom temporary radius rsb in the above formula is the lower half ring basic radius (rsb±Ecv). Also, the value obtained by subtracting the rotor radius R from this lower half ring basic radius (rsb±Ecv) is the lower half basic clearance (rsb±Ecv-R).

[0081] In the clearance calculation step S11, the left clearance Cl is obtained by subtracting the rotor radius R from the value obtained by adding or subtracting the horizontal axis misalignment amount Ecl and the radius change amount Δr to the left temporary radius rsl of the ring measured in the lower half ring temporary radius measurement step S4, as shown in the following formula. Cl=[rsl-Ecl+Δr]-R

[0082] In the above formula, the horizontal axis displacement Ecl is subtracted from the left temporary radius rsl of the ring because the horizontal axis displacement Ecl (=Acl-Ahcl) is a positive value. On the other hand, if the horizontal axis displacement Ecl (=Acl-Ahcl) is a negative value, the horizontal axis displacement Ecl is added to the left temporary radius rsl of the ring. Also, in the above formula, the radius change Δr (=rc-rb) is added to the left temporary radius rsl of the ring. However, if the radius change Δr is defined as the value obtained by subtracting the connection state temporary radius rc from the support state temporary radius rb (rb-rc), then the radius change Δr is subtracted from the left temporary radius rsl of the ring.

[0083] As described above, whether to add or subtract the horizontal axis displacement Ecl and the radius change Δr from the left temporary radius rsl of the ring depends on whether these values ​​are positive or negative, and further, on the definitions of these values.

[0084] Furthermore, the value obtained by adding or subtracting the horizontal axis misalignment amount Ecl from the left temporary radius of the ring rsl in the above formula is the lower half ring basic radius (rsl ± Ecl). Also, the value obtained by subtracting the rotor radius R from this lower half ring basic radius (rsl ± Ecl) is the lower half basic clearance (rsl ± Ecl - R).

[0085] In the clearance calculation step S11, the right-side clearance Cr is obtained by subtracting the rotor radius R from the value obtained by adding or subtracting the horizontal axis misalignment amount Ecl and the radius change amount Δr to the right temporary radius rsr of the ring measured in the lower half-ring temporary radius measurement step S4, as shown in the following formula. Cr = [rsr + Ecl + Δr] - R

[0086] Note that in the above formula, the horizontal axis misalignment amount Ecl is added to the right temporary radius rsr of the ring because, in this case, the horizontal axis misalignment amount Ecl (=Acl-Ahcl) is a positive value. On the other hand, if the horizontal axis misalignment amount Ecl (=Acl-Ahcl) is a negative value, then the horizontal axis misalignment amount Ecl is subtracted from the right temporary radius rsr of the ring. In other words, when calculating the left clearance Cl, the horizontal axis misalignment amount Ecl is added, and when calculating the right clearance Cl, this horizontal axis misalignment amount Ecl is subtracted.

[0087] As described above, whether to add or subtract the horizontal axis displacement Ecl and the radius change Δr from the right temporary radius rsr of the ring depends on whether these values ​​are positive or negative, and further, on the definitions of these values.

[0088] Furthermore, the value obtained by adding or subtracting the horizontal axis misalignment amount Ecl from the right temporary radius of the ring rsr in the above formula is the lower half ring basic radius (rsr±Ecl). Also, the value obtained by subtracting the rotor radius R from this lower half ring basic radius (rsr±Ecl) is the lower half basic clearance (rsr±Ecl-R).

[0089] The above allows us to determine the top clearance Ct, bottom clearance Cb, left-side clearance Cl, and right-side clearance Cr between the seal ring 45 and the rotor 10.

[0090] As described above, in this embodiment, the clearances Ct, Cb, Cl, and Cr between the seal ring 45 and the rotor 10 can be obtained without temporarily assembling the rotor 10 inside the casing 20, thus reducing the effort required to determine the seal clearance.

[0091] In the above embodiments, the upper half clearance is obtained by adding or subtracting the radius change amount Δr, etc., to the upper half basic clearance, but the upper half basic clearance may be used as is. Also, in the above embodiments, the lower half clearance is obtained by adding or subtracting the radius change amount Δr, etc., to the lower half basic clearance, but the lower half basic clearance may be used as is.

[0092] The axial-flow rotating machine in the above embodiment is a single-flow steam turbine into which one type of steam flows. However, the axial-flow fluid machine may also be a double-flow steam turbine into which two types of steam, namely high-pressure steam and low-pressure steam, flow. In this case, one side of the casing in the direction of the rotor axis forms a high-pressure chamber, and the other side of the casing in the direction of the rotor axis forms a low-pressure chamber. High-pressure steam flows into the high-pressure chamber, and low-pressure steam flows into the low-pressure chamber.

[0093] Although embodiments of this disclosure have been described in detail above, this disclosure is not limited to the embodiments described above. Various additions, modifications, substitutions, and partial deletions are possible, provided that they do not depart from the conceptual idea and spirit of the present invention derived from the claims and their equivalents.

[0094] "Addendum" The method for estimating the seal clearance of an axial flow rotating machine in the above embodiments can be understood, for example, as follows.

[0095] (1) The method for estimating the seal clearance of an axial flow rotating machine in the first embodiment is applicable to the following axial flow rotating machines. This axial flow rotary machine comprises a rotor 10 rotatable about a rotor axis Ar extending horizontally, a casing 20 covering the outer circumference of the rotor 10, a seal ring 45 forming an annular shape around the rotor axis Ar and positioned on the inner circumference of the casing 20 and the outer circumference of the rotor 10, and a seal retaining ring 40 forming an annular shape around the rotor axis Ar, attached to the inner circumference of the casing 20, and holding the seal ring 45 on its own inner circumference. The casing 20 has a semi-circular upper casing 20u forming the upper part with respect to the rotor axis Ar, and a semi-circular lower casing 20l forming the lower part with respect to the rotor axis Ar. The seal retaining ring 40 has a semi-circular upper seal retaining ring 40u that forms the upper part with respect to the rotor axis Ar and is attached to the upper half casing 20u, and a semi-circular lower seal retaining ring 40l that forms the lower part with respect to the rotor axis Ar and is attached to the lower half casing 20l. The seal ring 45 has a semi-circular upper seal retaining ring 45u that forms the upper part with respect to the rotor axis Ar and is held on the inner circumference side of the upper seal retaining ring 40u, and a semi-circular lower seal retaining ring 45l that forms the lower part with respect to the rotor axis Ar and is held on the inner circumference side of the lower seal retaining ring 40l. The lower seal retaining ring 40l is supported from below by the lower half casing 20l and has a support position 35s. The above method for estimating the seal clearance between the seal ring 45 and the rotor 10 in an axial flow rotating machine includes: an upper half-seal retaining ring temporary axis grasping step S1 for grasping the upper half-seal retaining ring temporary axis Ahu, which is the temporary central axis Ah of the upper half-seal retaining ring 40u in a standalone state; a lower half-seal retaining ring temporary axis grasping step S2 for grasping the lower half-seal retaining ring temporary axis Ahl, which is the temporary central axis Ah of the lower half-seal retaining ring 40l in a standalone state; an upper half-seal retaining ring temporary radius measuring step S3 for assembling the upper half-seal retaining ring 45u into the upper half-seal retaining ring 40u and measuring the upper half-ring temporary radius rst, which is the distance from the upper half-seal retaining ring temporary axis Ahu to a predetermined position in the circumferential direction Dch with respect to the upper half-seal retaining ring 45u within the inner peripheral edge of the upper half-seal retaining ring 45u; and an upper half-ring temporary radius measuring step S3 for assembling the upper half-seal retaining ring 45u into the upper half-seal retaining ring 40u. The lower half seal ring 45l is assembled, and the following steps are performed: lower half ring temporary radius measurement step S4, which measures the distances from the lower half retaining ring temporary axis Ahl to a predetermined position in the circumferential direction Dch on the inner peripheral edge of the lower half seal ring 45l, which are the lower half ring temporary radii rsb, rsl, rsr; casing temporary axis grasping step S7, which grasps the casing temporary axis Ac, which is the temporary central axis Ah of the lower half casing 20l; assembly temporary axis grasping step S8, which grasps the assembly temporary axis Ahc, which is the temporary central axis Ah of the lower half seal retaining ring 40l assembled into the lower half casing 20l; and clearance calculation step S11, which determines the clearance of the upper half seal ring 45u at the predetermined position and the clearance of the lower half seal ring 45l at the predetermined position.In the upper half retaining ring temporary axis gripping step S1, the lower half retaining ring temporary axis gripping step S2, the casing temporary axis gripping step S7, and the assembly temporary axis gripping step S8, each of the upper half seal retaining ring 40u in its standalone state, the lower half seal retaining ring 40l in its standalone state, the lower half casing 20l, and the lower half seal retaining ring 40l assembled into the lower half casing 20l are designated as half retaining rings 40h, and each of the upper half retaining ring temporary axis Ahu, the lower half retaining ring temporary axis Ahl, the casing temporary axis Ac, and the assembly temporary axis Ahc are designated as temporary central axes Ah. In the half retaining ring 40h, in the first cross section which is the cross section at the first position in the axial direction to which the central axis Arc of the half retaining ring 40h extends, there are a plurality of mutually different inner circumferential surface positions Ph1 in the circumferential direction Dch with respect to the central axis Arc. The process includes: a first measurement step S21 to take measurements; a second measurement step S22 to measure a plurality of different inner circumferential surface positions Ph2 in the circumferential direction Dch with respect to the central axis Arc, using a second cross-section which is a cross-section at a second position different from the first position in the axial direction within the semi-holding ring 40h; and a provisional central axis calculation step S23 which determines a first central position Cc1 which is the center position of a first approximate circle CA1 that passes through positions close to each of the plurality of inner circumferential surface positions Ph1 obtained in the first measurement step S21, and a second central position Cc2 which is the center position of a second approximate circle CA2 that passes through positions close to each of the plurality of inner circumferential surface positions Ph2 obtained in the second measurement step S22, and sets the line connecting the first central position Cc1 and the second central position Cc2 as a provisional central axis Ah.In the clearance calculation step S11, the axial misalignment amounts Ecv and Ech, which are the amount of misalignment of the assembled temporary shaft Ahc relative to the casing temporary shaft Ac, are determined, and the upper basic clearance is determined by subtracting the rotor radius R, which is the radius of the portion of the rotor 10 facing the upper seal ring 45u, from the upper basic radius, which is the value obtained by adding or subtracting the axial misalignment amount Ecv from the upper basic radius rst, and based on the upper basic clearance, the front of the upper seal ring 45u The clearance Ct at the predetermined position is determined, the lower half basic clearance is determined by subtracting the rotor radius R, which is the radius of the portion of the rotor 10 facing the lower half seal ring 45l, from the lower half basic radius, which is the value obtained by subtracting or adding the axial misalignment amounts Ecv and Ech to the lower half ring temporary radii rsb, rsl, and rsr, and based on the lower half basic clearance, the clearances Cb, Cl, and Cr of the lower half seal ring 45l at the predetermined position are determined.

[0096] In this embodiment, the clearance between the seal ring 45 and the rotor 10 can be obtained without temporarily assembling the rotor 10 inside the casing 20, thus reducing the effort required to determine the seal clearance.

[0097] (2) The method for estimating the seal clearance of an axial flow rotating machine in the second embodiment is: In the method for estimating the seal clearance of an axial flow rotating machine according to the first embodiment, in the upper half ring temporary radius measurement step S3, the upper half seal ring 45u is assembled into the upper half seal retaining ring 40u in a state where the central axis Arc of the semicircle extends in the vertical direction Dv, and the upper half ring temporary radius rst is measured. In the lower half ring temporary radius measurement step S4, the lower half seal ring 45l is assembled into the lower half seal retaining ring 40l in a state where the central axis Arc of the semicircle extends in the vertical direction Dv, and the lower half ring temporary radii rsb, rsl, and rsr are measured.

[0098] When measuring a predetermined position within the inner circumference of the upper seal ring 45u or the lower seal ring 45l, a three-dimensional measuring device 50 is used. This three-dimensional measuring device 50 generally irradiates a target with laser light, receives the laser light reflected from the target, and measures the three-dimensional position of the target. In addition, the upper seal retaining ring 40u in an axial flow rotating machine basically holds multiple upper seal rings 45u. The lower seal retaining ring 40l in an axial flow rotating machine basically holds multiple lower seal rings 45l. That is, the half-seal retaining ring 40 in an axial flow rotating machine basically holds multiple half-seal rings 38u, 38l. Moreover, the distance from the central axis Arc of the semi-circular half-seal retaining ring 40 to the inner circumference of each of the multiple half-seal rings 38u, 38l may differ for each of the multiple half-seal rings 38u, 38l.

[0099] Here, we assume that multiple semi-seal rings 38u, 38l are incorporated into a semi-seal retaining ring 40 in which the central axis Arc extends horizontally, and that predetermined positions on the inner circumference of each of the multiple semi-seal rings 38u, 38l are measured using the aforementioned three-dimensional measuring device 50. In this case, since it is difficult to position the three-dimensional measuring device 50 opposite the inner circumference of the semi-seal retaining ring 40, the three-dimensional measuring device 50 will be positioned on one side and the other side of the axial direction (horizontal direction) in which the central axis of the semi-seal retaining ring 40 extends, with the semi-seal retaining ring 40 as the reference. When the three-dimensional measuring device 50 is positioned in this way, the laser beam from the three-dimensional measuring device 50 may interfere with the semi-seal rings 38u, 38l, etc., which have a long distance from the central axis Arc of the semi-seal retaining ring 40 to their inner circumference, when measuring the position of the inner circumference of the semi-seal rings 38u, 38l, which have a short distance from the central axis Arc of the semi-seal retaining ring 40 to their inner circumference. In other words, it may not be possible to measure the position of the inner periphery of some of the multiple semi-seal rings 38u, 38l.

[0100] On the other hand, in this embodiment, when a plurality of semi-seal rings 38u, 38l are incorporated into a semi-seal retaining ring 40 in which the central axis Arc extends in the vertical direction Dv, and a predetermined position on the inner circumference of each of the plurality of semi-seal rings 38u, 38l is measured using the three-dimensional measuring device 50 described above, it is easy to position the three-dimensional measuring device 50 opposite the inner circumference of the semi-seal retaining ring 40. For this reason, in this embodiment, when measuring the position of the inner circumference of some of the semi-seal rings 38u, 38l, as in the case described above, interference between the laser beam from the three-dimensional measuring device 50 and other semi-seal rings 38u, 38l can be easily avoided. Thus, in this embodiment, even if the distance from the central axis Arc of the semi-circular semi-seal retaining ring 40 to the inner circumference of each of the plurality of semi-seal rings 38u, 38l differs for each of the plurality of semi-seal rings 38u, 38l, the position of the inner circumference of all of the semi-seal rings 38u, 38l can be easily measured.

[0101] (3) The method for estimating the seal clearance of an axial flow rotating machine in the third embodiment is: In the method for estimating the seal clearance of an axial flow rotating machine according to the second embodiment, in the upper half retaining ring temporary axis grasping step S1, the first measurement step S21 and the second measurement step S22 are performed on the upper half seal retaining ring 40u in a standalone state where the central axis Arc of the semicircular arc of the upper half seal retaining ring 40u extends in the vertical direction Dv, to grasp the upper half retaining ring temporary axis Ahu. In the lower half retaining ring temporary axis grasping step S2, the first measurement step S21 and the second measurement step S22 are performed on the lower half seal retaining ring 40l in a standalone state where the central axis Arc of the semicircular arc of the lower half seal retaining ring 40l extends in the vertical direction Dv, to grasp the lower half retaining ring temporary axis Ahl.

[0102] In this embodiment, after the upper half-holding ring temporary axis gripping step S1 and the lower half-holding ring temporary axis gripping step S2, the upper half-ring temporary radius measurement step S3 and the lower half-ring temporary radius measurement step S4 can be performed without changing the installation state of the half-holding ring 40h.

[0103] (4) The method for estimating the seal clearance of an axial flow rotating machine in the fourth embodiment is: In the method for estimating the seal clearance of an axial flow rotating machine according to the third embodiment, a connection state determination step S6 is performed to determine the connection state temporary radius rc, which is the distance from the temporary central axis Ah of the connection state, which is the connection state temporary axis, to the inner circumferential surface of the lower half seal retaining ring 40l, when the lower half seal retaining ring 40l is supported from below at the support position 35s and connected to the upper half seal retaining ring 40u, and the lower half seal ring 45l is not incorporated. The connection state determination step S6 includes a measurement step S31 in which a plurality of inner circumferential surface positions Phs that are different in the circumferential direction Dch within the lower half seal retaining ring 40l in a state in which the lower half seal retaining ring 40l is supported from below at the support position 35s and connected to the upper half seal retaining ring 40u and the lower half seal ring 45l is not incorporated, and an approximate circle setting step S32 in which an approximate circle CAs passing through positions close to each of the plurality of inner circumferential surface positions Phs obtained in the measurement step S31 is determined and the radius of the approximate circle CAs is set as the connection state temporary radius rc. In the clearance calculation step S11, the radius change amount Δr is obtained by subtracting the support state temporary radius rb, which is the radius of the first approximate circle CA1 or the second approximate circle CA2 obtained in the lower half holding ring temporary axis grasping step S2, from the connection state temporary radius rc. Based on the value obtained by adding or subtracting the radius change amount Δr to the upper half basic clearance, the clearance Ct at the predetermined position of the upper half seal ring 45u is determined, and based on the value obtained by subtracting or adding the radius change amount to the lower half basic clearance, the clearances Cb,Cl,Cr at the predetermined position of the lower half seal ring 45l are determined.

[0104] In this embodiment, the change in the radius of the half-seal retaining ring 40 when the lower half-seal retaining ring 40l and the upper half-seal retaining ring 40u are connected can be reflected in the clearance.

[0105] (5) The method for estimating the seal clearance of an axial flow rotating machine in the fifth embodiment is: In the method for estimating the seal clearance of an axial flow rotating machine according to any one of the first to fourth embodiments, the predetermined position of the upper seal ring 45u includes the central position of the circumferential Dcs with respect to the upper seal ring 45u within the inner peripheral edge of the upper seal ring 45u. The predetermined position of the lower seal ring 45l includes the central position of the circumferential Dcs with respect to the lower seal ring 45l within the inner peripheral edge of the lower seal ring 45l. In the clearance calculation step S11, the vertical axial misalignment amount Ecv is determined as the axial misalignment amount Ecv, Ech, which is the axial misalignment amount Ecv of the assembled temporary shaft Ahc in the vertical direction Dv relative to the casing temporary shaft Ac. When determining the clearance Ct at the center position in the circumferential direction Dcs with respect to the upper half seal ring 45u, the vertical axial misalignment amount Ecv is used as the axial misalignment amount Ecv, Ech. When determining the clearance Cb at the center position in the circumferential direction Dcs with respect to the lower half seal ring 45l, the vertical axial misalignment amount Ecv is used as the axial misalignment amount Ecv, Ech.

[0106] In this embodiment, a top clearance Ct can be obtained between the seal ring 45 and the rotor 10 at a position vertically above the rotor axis Ar, and a bottom clearance Cb can be obtained between the seal ring 45 and the rotor 10 at a position vertically above the rotor axis Ar.

[0107] (6) The method for estimating the seal clearance of an axial flow rotating machine in the sixth embodiment is: In the fifth embodiment of the method for estimating the seal clearance of an axial flow rotating machine, the amount of deflection d of the rotor 10 at the position where the seal ring 45 is provided in the axial direction in which the rotor axis Ar extends is obtained in advance. In the clearance calculation step S11, the clearance Ct at the predetermined position of the upper seal ring 45u is determined based on the value obtained by adding the amount of deflection d to the upper basic clearance, and the clearance Cb at the predetermined position of the lower seal ring 45l is determined based on the value obtained by subtracting the amount of deflection d from the lower basic clearance.

[0108] In this embodiment, the amount of deflection d of the rotor 10 can be reflected in the top clearance Ct and the bottom clearance Cb.

[0109] (7) The method for estimating the seal clearance of an axial flow rotating machine in the seventh embodiment is: In the fifth or sixth embodiment of the method for estimating the seal clearance of an axial flow rotating machine, a support state determination step S5 and a connection state determination step S6 are further performed. In the support state determination step S5, the radius of the first approximate circle CA1 or the second approximate circle CA2 obtained in the lower half retaining ring temporary axis determination step S2 is set as the temporary support state radius rb, and further, the vertical support state distance hb is determined, which is the distance in the vertical direction Dv between the center of the first approximate circle CA1 or the second approximate circle CA2 of the lower half seal retaining ring 40l and the support position 35s when the lower half seal retaining ring 40l is supported from below at the support position 35s, is not connected to the upper half seal retaining ring 40u, and the lower half seal ring 45l is not incorporated. The connection state determination step S6 includes a measurement step S31 in which a plurality of inner circumferential surface positions that are different in the circumferential direction are measured in the lower half seal retaining ring 40l in a state in which the lower half seal retaining ring 40l is supported from below at the support position 35s and connected to the upper half seal retaining ring 40u and the lower half seal ring 45l is not incorporated, and an approximate circle setting step S32 in which an approximate circle CAs is determined that passes through positions close to each of the plurality of inner circumferential surface positions obtained in the measurement step, the radius of the approximate circle CAs is set as the connection state temporary radius rc, and the connection state vertical distance hc is determined to be the distance in the vertical direction Dv between the center of the approximate circle CAs and the support position 35s. In the clearance calculation step S11, the vertical axial misalignment amount Ecv is determined as the axial misalignment amount Ecv, Ech, which is the axial misalignment amount Ecv of the assembled temporary shaft Ahc in the vertical direction Dv relative to the casing temporary shaft Ac. The axial displacement amount Δh is determined as the value obtained by subtracting the vertical distance hb of the support state from the vertical distance hc of the connection state. When determining the clearance Ct at the center position of the circumferential direction Dcs with respect to the upper half seal ring 45u, the vertical axial misalignment amount Ecv is used as the axial misalignment amount Ecv, Ech, including the axial displacement amount Δh, and when determining the clearance Cb at the center position of the circumferential direction Dcs with respect to the lower half seal ring 45l.

[0110] In this embodiment, a top clearance Ct can be obtained between the seal ring 45 and the rotor 10 at a position vertically above the rotor axis Ar, and a bottom clearance Cb can be obtained between the seal ring 45 and the rotor 10 at a position vertically above the rotor axis Ar. Furthermore, in this embodiment, the change in the radius of the half-seal retaining ring 40 when the lower half-seal retaining ring 40l and the upper half-seal retaining ring 40u are connected can be reflected in the top clearance Ct and the bottom clearance Cb.

[0111] (8) The method for estimating the seal clearance of an axial flow rotating machine in the eighth aspect is: In the method for estimating the seal clearance of an axial flow rotating machine according to any one of the fifth to seventh embodiments described above, the method further includes: an assembly state vertical distance measurement step S9, which measures the assembled state vertical distance Hb, which is the vertical distance Dv between the temporary casing shaft Ac and the support position 35s of the lower seal retaining ring 40l incorporated into the lower casing 20l, with the upper casing 20u not connected; and an assembly connection state vertical distance measurement step S10, which measures the assembled connection state vertical distance Hc, which is the vertical distance Dv between the temporary casing shaft Ac and the support position 35s of the lower seal retaining ring 40l incorporated into the lower casing 20l, with the upper casing 20u connected. In the clearance calculation step S11, the casing displacement ΔH is obtained by subtracting the vertical distance Hb of the assembled state from the vertical distance Hc of the assembled connection state, and the clearance Ct of the upper seal ring 45u at the predetermined position is determined by including the casing displacement ΔH as the target for addition or subtraction to the upper basic clearance, and the clearance Cb of the lower seal ring 45l at the predetermined position is determined by including the casing displacement ΔH as the target for subtraction or addition to the lower basic clearance.

[0112] In this embodiment, the change in the height of the lower casing 20l when it changes from a state where the lower casing 20l and the upper casing 20u are not connected to a state where the lower casing 20l and the upper casing 20u are connected can be reflected in the top clearance Ct and bottom clearance Cb.

[0113] (9) The method for estimating the seal clearance of an axial flow rotating machine in the ninth aspect is: In the method for estimating the seal clearance of an axial flow rotating machine according to any one of the first to eight embodiments described above, the predetermined position of the lower half seal ring 45l includes the first end position and the second end position, which are the positions of both ends of the circumferential direction Dcs with respect to the lower half seal ring 45l, on the inner peripheral edge of the lower half seal ring 45l. In the clearance calculation step S11, the horizontal axial misalignment amount Ech is determined, which is the amount of axial misalignment in the horizontal direction of the built-in temporary shaft Ahc relative to the casing temporary shaft Ac, and when determining the clearances Cl and Cr at the first end position and the second end position of the circumferential direction Dcs with respect to the lower half seal ring 45l, the horizontal axial misalignment amount Ech is used as the axial misalignment amounts Ecv and Ech.

[0114] In this embodiment, a left-side clearance Cl can be obtained between the seal ring 45 and the rotor 10 at a position horizontally to the left of the rotor axis Ar, and a right-side clearance Cr can be obtained between the seal ring 45 and the rotor 10 at a position horizontally to the right of the rotor axis Ar. [Explanation of symbols]

[0115] 10: Rotor 11: Rotor shaft 12: Moving blade row 13: Moving blade 13b: Wing body 13r: Wing root 20: Casing 20u: Upper casing 20L: Lower half casing 21: Steam expansion chamber 22: Steam Inlet 23: Steam outlet 24h: High-pressure side gland bore section 24L: Low-pressure side gland bore section 27: Stationary Wing Arrow 28: Silent Wing 28b: Wing body 28i: Inner shroud 28o: Outer shroud 30: Wing ring 30u: upper half wing ring 30l: lower half wing ring 32: High-pressure seal retaining ring 33: First low-pressure seal retaining ring 34: Second low-pressure seal retaining ring 35u: Upper seal retaining ring 35L: Lower half seal retaining ring 35f: Flange 35s: Support position 36: Shaft seal ring 37: Rotary blade row seal ring 38u: Upper sealing ring 38L: Lower half sealing ring 40: Seal retaining ring 40h: Half retention ring 40u: Upper seal retaining ring 40L: Lower half seal retaining ring 45: Seal ring 45h: Half-seal ring 45u: Upper sealing ring 45L: Lower half sealing ring 46: Semi-holding ring of a specific state 50: Three-dimensional measuring device Ar: Rotor axis Ah: Temporary central axis Arc: Central axis line Ahu: Upper half retaining ring temporary axis Ahl: lower half retaining ring temporary shaft Ac: Casing temporary shaft Ahc: Built-in temporary shaft CA1, CA2, CAs: Approximate circles Cc1: First center position Cc2: Second center position rst: Link top temporary radius (upper half ring temporary radius) rsb: Ring bottom temporary radius (lower half ring temporary radius) rsl: Left temporary radius of the ring (lower half temporary radius of the ring) rsr: Right temporary radius of the ring (temporary radius of the lower half of the ring) rb: Support state temporary radius rc: Connection status temporary radius rh: Temporary radius in a specific state Δr: Radius change Ecv: Vertical axis misalignment (axis misalignment) Ech: Horizontal axis misalignment (axis misalignment) hb: Vertical distance of support state hc: Connection status vertical distance Δh: Axis displacement Hb: Vertical distance in the installed state Hc: Built-in connection state vertical distance ΔH: Casing displacement Ct: Top clearance (clearance) Cb: Bottom clearance (clearance) Cl: Left side clearance (clearance) Cr: Right side clearance (clearance) Ph1,Ph2,Phs: Inner surface position Da: Rotor axis direction Da1: First side Da2: Second side Dc, Dch, Dcs: Circumferential direction Dr: Radial direction Dri: Radial inner side Dro: Radial outer side Dh:Horizontal direction Dv; Vertical direction

Claims

1. A rotor that can rotate around a rotor axis that extends horizontally, A casing covering the outer circumference of the rotor, A seal ring is formed in an annular shape around the rotor axis and is positioned on the inner circumference of the casing and on the outer circumference of the rotor, A seal retaining ring is formed annularly around the rotor axis, attached to the inner circumference of the casing, and holds the seal ring on its own inner circumference, Equipped with, The casing comprises a semi-circular upper casing that forms the upper part with respect to the rotor axis, and a semi-circular lower casing that forms the lower part with respect to the rotor axis. The seal retaining ring comprises a semi-circular upper seal retaining ring that forms the upper portion with respect to the rotor axis and is attached to the upper half casing, and a semi-circular lower seal retaining ring that forms the lower portion with respect to the rotor axis and is attached to the lower half casing. The seal ring comprises a semi-circular upper seal ring that forms the upper portion with respect to the rotor axis and is held on the inner circumference side of the upper seal retaining ring, and a semi-circular lower seal ring that forms the lower portion with respect to the rotor axis and is held on the inner circumference side of the lower seal retaining ring, The lower half seal retaining ring is supported from below by the lower half casing and has a support position. In a method for estimating the seal clearance between the seal ring and the rotor in an axial flow rotating machine, A step of grasping the temporary axis of the upper half retaining ring, which is the temporary central axis of the upper half seal retaining ring in its standalone state, A step of grasping the temporary axis of the lower half retaining ring, which is the temporary central axis of the lower half seal retaining ring in its individual state, The upper half-ring temporary radius measurement step involves assembling the upper half-seal ring into the upper half-seal retaining ring and measuring the upper half-ring temporary radius, which is the distance from the temporary axis of the upper half-seal retaining ring to a predetermined position in the circumferential direction relative to the upper half-seal ring on the inner peripheral edge of the upper half-seal ring. A lower half-ring temporary radius measurement step, which involves assembling the lower half-seal ring into the lower half-seal retaining ring and measuring the lower half-ring temporary radius, which is the distance from the temporary axis of the lower half-seal retaining ring to a predetermined position in the circumferential direction relative to the lower half-seal ring on the inner peripheral edge of the lower half-seal ring, A casing temporary axis grasping step for grasping the casing temporary axis, which is the temporary central axis of the lower half casing, A temporary shaft grasping step for grasping the temporary shaft, which is the temporary central axis of the lower seal retaining ring incorporated into the lower casing, A clearance calculation step to determine the clearance of the upper seal ring at the predetermined position and the clearance of the lower seal ring at the predetermined position, Execute, The upper half-holding ring temporary shaft gripping process, the lower half-holding ring temporary shaft gripping process, the casing temporary shaft gripping process, and the assembly temporary shaft gripping process are as follows: Each of the upper half seal retaining ring in its standalone state, the lower half seal retaining ring in its standalone state, the lower half casing, and the lower half seal retaining ring incorporated into the lower half casing are defined as a half retaining ring. When the upper half-holding ring temporary axis, the lower half-holding ring temporary axis, the casing temporary axis, and the assembled temporary axis are each designated as temporary central axes, A first measurement step involves measuring a plurality of inner surface positions that are different from each other in the circumferential direction with respect to the central axis in the first cross section, which is the cross section at a first position in the axial direction in which the central axis of the semi-retaining ring extends, A second measurement step involves measuring a plurality of inner circumferential surface positions that are different from each other in the circumferential direction with respect to the central axis, in a second cross-section which is a cross-section at a second position different from the first position in the axial direction within the semi-retaining ring, A provisional center axis calculation step is performed by determining the first center position, which is the center position of the first approximate circle passing through positions close to each of the multiple inner surface positions obtained in the first measurement step, and determining the second center position, which is the center position of the second approximate circle passing through positions close to each of the multiple inner surface positions obtained in the second measurement step, and setting the line connecting the first center position and the second center position as the provisional center axis. Includes, In the clearance calculation process, The amount of axial misalignment, which is the amount of misalignment of the assembled temporary shaft relative to the casing temporary shaft, is determined. The upper half basic clearance is obtained by subtracting the rotor radius, which is the radius of the portion of the rotor facing the upper half seal ring, from the upper half basic radius, which is the value obtained by adding or subtracting the amount of axial misalignment from the upper half ring temporary radius. Based on the above upper basic clearance, the clearance at the predetermined position of the upper sealing ring is determined. The lower half basic clearance is obtained by subtracting or adding the amount of axial misalignment from the lower half basic radius, which is the value obtained by subtracting the rotor radius, which is the radius of the portion of the rotor facing the lower half seal ring. Based on the lower half basic clearance, the clearance at the predetermined position of the lower half seal ring is determined. A method for estimating seal clearance in axial flow rotating machinery.

2. In the method for estimating the seal clearance of an axial flow rotating machine according to claim 1, In the upper half ring temporary radius measurement step, the upper half seal ring is assembled into the upper half seal retaining ring in a state where the central axis of the semicircular arc extends in the vertical direction, and the upper half ring temporary radius is measured. In the lower half-ring temporary radius measurement step, the lower half-seal ring is assembled into the lower half-seal retaining ring in a state where the central axis of the semi-circular arc extends in the vertical direction, and the lower half-ring temporary radius is measured. A method for estimating seal clearance in axial flow rotating machinery.

3. In the method for estimating the seal clearance of an axial flow rotating machine according to claim 2, In the upper half retaining ring temporary axis grasping step, the first measurement step and the second measurement step are performed on the upper half seal retaining ring in a state where the central axis of the semicircular arc of the upper half seal retaining ring extends in the vertical direction, in which case the temporary axis of the upper half retaining ring is grasped. In the lower half retaining ring temporary axis grasping step, the first measurement step and the second measurement step are performed on the lower half seal retaining ring in a state where the central axis of the semicircular arc of the lower half seal retaining ring extends in the vertical direction, in which case the temporary axis of the lower half retaining ring is grasped. A method for estimating seal clearance in axial flow rotating machinery.

4. In the method for estimating the seal clearance of an axial flow rotating machine according to claim 3, Furthermore, a connection state determination step is performed to determine the connection state temporary radius, which is the distance from the temporary central axis of the lower seal retaining ring to the inner circumferential surface of the lower seal retaining ring, when the lower seal retaining ring is supported from below at the support position and connected to the upper seal retaining ring, and the lower seal ring is not assembled. The aforementioned connection status determination step is: A measurement step of measuring multiple inner surface positions that are different from each other in the circumferential direction within the lower seal retaining ring, in a state where the lower seal retaining ring is supported from below at the support position and connected to the upper seal retaining ring, and the lower seal ring is not incorporated therein, An approximate circle setting step is to determine an approximate circle that passes through a position close to each of the multiple inner surface positions obtained in the measurement step, and set the radius of the approximate circle as the temporary radius of the connection state, Includes, In the clearance calculation process, The radius change is obtained by subtracting the temporary radius of the support state, which is the radius of the first approximate circle or the second approximate circle obtained in the lower half-holding ring temporary axis grasping step, from the temporary radius of the connection state. Based on the value obtained by adding or subtracting the radius change amount to the upper half basic clearance, the clearance at the predetermined position of the upper half seal ring is determined. The clearance at the predetermined position of the lower seal ring is determined based on the value obtained by subtracting or adding the radius change amount to the lower basic clearance. A method for estimating seal clearance in axial flow rotating machinery.

5. In the method for estimating the seal clearance of an axial flow rotating machine according to claim 1, The predetermined position of the upper seal ring includes the central position in the circumferential direction relative to the upper seal ring, within the inner peripheral edge of the upper seal ring. The predetermined position of the lower half seal ring includes the central position in the circumferential direction relative to the lower half seal ring, within the inner peripheral edge of the lower half seal ring. In the clearance calculation process, As the amount of axial misalignment, the vertical axial misalignment is determined, which is the amount of axial misalignment of the assembled temporary shaft in the vertical direction relative to the casing temporary shaft. When determining the clearance at the circumferential center position of the upper seal ring, the amount of vertical axial misalignment is used as the amount of axial misalignment. When determining the clearance at the circumferential center position of the lower half seal ring, the amount of vertical axial misalignment is used as the amount of axial misalignment. A method for estimating seal clearance in axial flow rotating machinery.

6. In the method for estimating the seal clearance of an axial flow rotating machine according to claim 5, The amount of deflection of the rotor at the position where the seal ring is provided, in the axial direction in which the rotor axis extends, is obtained in advance. In the clearance calculation process, Based on the value obtained by adding the deflection amount to the upper half basic clearance, the clearance at the predetermined position of the upper half seal ring is determined. Based on the value obtained by subtracting the amount of deflection from the lower half basic clearance, the clearance of the lower half seal ring at the predetermined position is determined. A method for estimating seal clearance in axial flow rotating machinery.

7. In the method for estimating the seal clearance of an axial flow rotating machine according to claim 5 or 6, Furthermore, the support state determination process and the connection state determination process are performed. In the support state determination step, the radius of the first approximate circle or the second approximate circle determined in the lower half retaining ring temporary axis determination step is set as the temporary radius of the support state, and further, the vertical distance of the support state is determined, which is the vertical distance between the center of the first approximate circle or the second approximate circle of the lower half seal retaining ring and the support position when the lower half seal retaining ring is supported from below at the support position, is not connected to the upper half seal retaining ring, and the lower half seal ring is not assembled. The aforementioned connection status determination step is: A measurement step of measuring multiple inner surface positions that are different from each other in the circumferential direction within the lower seal retaining ring, in a state where the lower seal retaining ring is supported from below at the support position and connected to the upper seal retaining ring, and the lower seal ring is not incorporated therein, An approximate circle setting step is performed in which an approximate circle is determined that passes through a position close to each of the multiple inner surface positions obtained in the measurement step, the radius of the approximate circle is set as the temporary radius of the connection state, and the vertical distance of the connection state, which is the vertical distance between the center of the approximate circle and the support position, Includes In the clearance calculation process, As the amount of axial misalignment, the vertical axial misalignment is determined, which is the amount of axial misalignment of the assembled temporary shaft in the vertical direction relative to the casing temporary shaft. The axial displacement is obtained by subtracting the vertical distance of the support state from the vertical distance of the connection state. When determining the clearance at the circumferential center position of the upper seal ring, The amount of vertical axial misalignment is used as the amount of axial misalignment, including the amount of axial displacement, to be added to or subtracted from the upper basic clearance. When determining the clearance at the circumferential center position of the lower half seal ring, the amount of vertical axial misalignment is used as the amount of axial misalignment, including the amount of axial displacement, to be subtracted from or added to the lower half basic clearance. A method for estimating seal clearance in axial flow rotating machinery.

8. In the method for estimating the seal clearance of an axial flow rotating machine according to claim 5 or 6, Furthermore, the assembly state vertical distance measurement step measures the vertical distance between the temporary shaft of the casing and the support position of the lower seal retaining ring incorporated into the lower casing, while the upper casing is not connected. With the upper half casing connected, the vertical distance of the assembled connection state is measured, which is the vertical distance between the temporary axis of the casing and the support position of the lower half seal retaining ring incorporated into the lower half casing. Execute, In the clearance calculation process, The casing displacement is obtained by subtracting the vertical distance of the assembled connection state from the vertical distance of the assembled connection state. The clearance at the predetermined position of the upper seal ring is determined by including the casing displacement amount as an item to be added to or subtracted from the upper basic clearance, The clearance at the predetermined position of the lower seal ring is determined by including the casing displacement amount as the target for subtraction or addition to the lower basic clearance. A method for estimating seal clearance in axial flow rotating machinery.

9. A method for estimating the seal clearance of an axial flow rotating machine according to any one of claims 1 to 6, The predetermined position of the lower half seal ring includes the first end position and the second end position, which are the circumferential positions of both ends of the lower half seal ring on its inner periphery, In the clearance calculation process, The amount of horizontal axial misalignment, which is the amount of axial misalignment of the assembled temporary shaft relative to the casing temporary shaft, is determined. When determining the clearance at the first and second end positions in the circumferential direction with respect to the lower half seal ring, the amount of horizontal axial misalignment is used as the amount of axial misalignment. A method for estimating seal clearance in axial flow rotating machinery.

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