METHOD FOR CALCULATING THE AMOUNT OF CHANGE IN THE GAME OF THE SHOVEL RING AND METHOD FOR ADJUSTING THE POSITION OF THE SHOVEL RING

Abstract

The present invention relates to a method for calculating the amount of a change in the clearance of a blade ring and a method for adjusting the position of the blade ring. This method for calculating the amount of change in the clearance of a blade ring calculates the amount of change in the clearance in a vertical direction between an inner circumferential surface of the blade ring and an outer circumferential surface of a rotating shaft arranged inside the blade ring, wherein the blade ring is configured with a ring shape by joining a blade ring upper half section and a blade ring lower half section.The procedure comprises: a step to detect a displacement magnitude in a horizontal direction of the blade ring between a first state in which the blade ring upper half section is connected to the blade ring lower half section, and a second state in which the blade ring upper half section has been removed from the blade ring lower half section; a step to calculate a second neutral axis of the blade ring in the second state based on the displacement magnitude; and a step to calculate the magnitude of change of a clearance between the first state and the second state by comparing a first neutral axis of the blade ring in the first state with the second neutral axis.

Description

Technical field

[0001] The present disclosure relates to a method for calculating the amount of a change in the play of a paddle ring and a method for adjusting the position of a paddle ring. State of the art

[0002] A steam turbine, as a rotary machine, comprises a casing, a rotor, a stator blade, and a rotor blade. Within the casing, a rotor is rotatably mounted, and several rotor blades are attached to the rotor at axial intervals. Additionally, several stator blades are attached to the casing at axial intervals. The stator and rotor blades are arranged alternately in the axial direction. A blade ring is attached to an inner circumferential section of the casing. The blade ring is configured such that the multiple stator blades are spaced circumferentially between an outer and an inner ring and has an annular shape. The blade ring is divided into two sections in an up-down direction and is secured by a bolt to maintain its annular shape.

[0003] The casing is disassembled in such a way that an outer casing upper half section, an inner casing upper half section, and a blade ring upper half section are removed in that order, and finally the rotor is removed. The casing is assembled using the reverse disassembly procedure. It is necessary to adjust the clearance between the outer circumferential surface of the rotor and the inner circumferential surface of the blade ring so that it has a suitable value when the casing is assembled. In particular, the blade ring may gradually deform over time, and creep deformation may occur. Therefore, the casing is temporarily pre-assembled, and the clearance between the outer circumferential surface of the rotor and the inner circumferential surface of the blade ring is measured using measuring equipment. For example, this technique is disclosed in PTL 1. List of citations from patent literature

[0004] [PTL 1] Japanese Patent No. 5501875 Summary of the invention: Technical problem

[0005] According to the technique disclosed in PTL 1, the clearance between the outer circumferential surface of the rotor and the inner circumferential surface of the blade ring is measured using measuring technology. In this case, it is necessary to perform temporary assembly work on the housing or the blade ring, and this temporary assembly work is time-consuming, resulting in poor work efficiency.

[0006] The present disclosure was made to solve the problems described above, and one objective of the present disclosure is to provide a method for calculating the amount of a change in the clearance of a blade ring and a method for adjusting the position of a blade ring to achieve improved machinability in housing assembly work. Solution to the problem

[0007] According to the present disclosure, to achieve the above-described problem, a method is provided for calculating the amount of a change in the clearance of a blade ring, wherein a blade ring having a ring shape is configured by connecting a blade ring upper half section and a blade ring lower half section, and the amount of the change in the clearance in a vertical direction between an inner circumferential surface of the blade ring and an outer circumferential surface of a rotating shaft arranged inside the blade ring is calculated.The method comprises a step of detecting a displacement magnitude in a horizontal direction of the blade ring in a first state in which the blade ring upper half section is connected to the blade ring lower half section, and a second state in which the blade ring upper half section has been removed from the blade ring lower half section, a step of calculating a second neutral axis of the blade ring in the second state based on the displacement magnitude, and a step of calculating the magnitude of the change in clearance between the first state and the second state by comparing a first neutral axis of the blade ring in the first state with the second neutral axis.

[0008] Furthermore, according to the present disclosure, a method for adjusting the position of a blade ring is provided. When a blade ring upper half section is assembled with a blade ring lower half section, the position of the blade ring is adjusted in a vertical direction based on the amount of the change in clearance, which is calculated by the method for calculating the amount of a change in clearance of a blade ring. Advantageous effects of the invention

[0009] According to the method for calculating the amount of the change in the blade ring clearance and the method for adjusting the position of the blade ring of the present disclosure, improved machinability can be achieved during housing assembly work. Brief description of the drawings Fig. Figure 1 is a schematic diagram showing an internal configuration of a steam turbine. Fig. Figure 2 is a schematic diagram showing the interior of a steam turbine casing. Fig. Figure 3 is a view for describing the amount of a change in a game that corresponds to the creep deformation of a paddle ring. Fig. Figure 4 is a flowchart showing a method for calculating the amount of change in the clearance of the paddle ring of a first embodiment. Fig. Figure 5 is a view describing a procedure for calculating the amount of change in the play of the paddle ring. Fig. Figure 6 is a flowchart showing a procedure for adjusting the position of the paddle ring. Fig. Figure 7 is a view describing a method for calculating the amount of a change in the clearance of a paddle ring of a second embodiment. Fig. Figure 8 is an enlarged view to describe the procedure for calculating the amount of change in the paddle ring's play. Fig. Figure 9 is a flowchart showing a procedure for calculating the amount of change in the clearance of the paddle ring of the second embodiment. Description of embodiments

[0010] Preferred embodiments of the present disclosure are described in detail below with reference to the drawings. The present disclosure is not limited by the embodiments, and where several embodiments are provided, the present disclosure also includes a configuration in which the respective embodiments are combined. Furthermore, configuration elements in the embodiments include those that a person skilled in the art can readily deduce, those that are substantially the same, and those that have a so-called equivalent scope of protection. [First embodiment] <dampfturbine>

[0011] In a first embodiment, a method for calculating the magnitude of a change in the clearance of a blade ring and a method for adjusting the position of a blade ring are described by applying the methods to a steam turbine as a lathe. However, the lathe is not limited to the steam turbine. Fig. Figure 1 is a schematic diagram showing an internal configuration of the steam turbine.

[0012] In the first embodiment, the steam turbine is described as the lathe. However, the lathe is not limited to the steam turbine and can have a configuration in which a rotating body is rotatably mounted relative to a stationary body.

[0013] As in Fig. Figure 1 shows a steam turbine (rotary machine) 10, a casing (stationary body) 11, a rotor (rotating shaft) 12, a stator blade 13 and a rotor blade 14.

[0014] The housing 11 has a hollow shape, and the rotor 12 is arranged inside the housing 11 along a horizontal direction. The rotor 12 is rotatably mounted about an axis O1 by bearings 21 and 22, which are provided in the housing 11 (or a foundation of a system). Several of the stator blades 13 are attached to an inner circumferential section of the housing 11 at intervals along an axial direction A of the rotor 12. Several of the rotor blades 14 are attached to an outer circumferential section of the rotor 12 at intervals along the axial direction A. The stator blades 13 are arranged along a radial direction R of the rotor 12 and are spaced at intervals along a circumferential direction of the rotor 12. The rotor blades 14 are arranged along the radial direction R of the rotor 12 and are spaced at intervals along the circumferential direction of the rotor 12. The stator blades 13 and the rotor blades 14 are arranged alternately in the axial direction A.

[0015] The housing 11 has a steam supply port 23 in one end section in the axial direction A. The steam supply port 23 communicates with a blade row section 25, in which the stator blade 13 and the rotor blade 14 are arranged, via a steam channel 24. The blade row section 25 communicates with an exhaust chamber 26. The housing 11 has a steam discharge port 27 in the other end section in the axial direction A. The steam discharge port 27 communicates with the exhaust chamber 26.

[0016] High-pressure steam is supplied to the rotor blade section 25 from the steam supply port 23 through the steam channel 24. The rotor 12 is driven and rotated via each of the rotor blades 14 by the steam flowing over the multiple stator blades 13 and the multiple rotor blades 14. A generator (not shown) is connected to the rotor 12, and the generator is driven by a motive force from the rotor 12. The steam driving each of the rotor blades 14 is discharged to the outside from the steam discharge port 27 through the exhaust chamber 26. <schaufelring>

[0017] Fig. Figure 2 is a schematic diagram showing the interior of a steam turbine casing.

[0018] As in Fig. As shown in Figure 2, a housing 31, forming the housing 11, is of a type divided into two sections in an up-down direction and has a ring shape in which an upper housing half section 32 and a lower housing half section 33 are connected by a bolt (not shown). The blade ring 34 comprises an outer ring 35, an inner ring 36, and the multiple stator blades 13. The multiple stator blades 13 are arranged at a circumferential distance between the outer ring 35 and the inner ring 36. As with the housing 31, the blade ring 34 is of the type divided into two sections in the up-down direction and has a ring shape in which an upper blade ring half section 37 and a lower blade ring half section 38 are connected by a bolt (not shown). The blade ring 34 is arranged inside the housing 31 and is supported by support sections 39 and 40. <Kriechverformung von Schaufelring>

[0019] Fig. Figure 3 is a view to describe the amount of the change in play that corresponds to the creep deformation of the paddle ring.

[0020] As in Fig. As shown in Figure 3, creep deformation occurs in the blade ring 34 during operation of the steam turbine. Therefore, when the casing 31 is disassembled and the blade ring 34 is subsequently removed, the blade ring upper half section 37 and the blade ring lower half section 38 are released from their bolt fixings. Consequently, creep deformation occurs. That is, the blade ring upper half section 37 and the blade ring lower half section 38 are slightly curved towards one inner circumferential side, and the mounting surfaces 37a and 37b and mounting surfaces 38a and 38b are not parallel to each other.

[0021] When the blade ring 34 is mounted, the creep deformation is corrected in a case where the blade ring upper half section 37 and the blade ring lower half section 38 are connected by a bolt. That is, the blade ring upper half section 37 and the blade ring lower half section 38 are slightly curved on an outer circumferential side, and the mounting surfaces 37a and 37b and the mounting surfaces 38a and 38b are parallel to each other. However, since the blade ring lower half section 38 rises slightly with respect to the rotor 12, the clearance S in a vertical direction in a lower section is reduced and narrowed at an outer circumferential surface of the rotor 12 and at an inner circumferential surface of the blade ring 34. <Verfahren zum Berechnen von Betrag an Änderung von Spiel von Schaufelring>

[0022] Fig. Figure 4 is a flowchart showing a method for calculating the amount of change in the clearance of the paddle ring of the first embodiment, and Fig. Figure 5 is a view describing a procedure for calculating the amount of change in the play of the paddle ring.

[0023] As in Fig. As shown in Figure 3, in the method for calculating the amount of the change in the clearance of the blade ring of the first embodiment, the blade ring 34 is configured such that it has a ring shape by connecting the blade ring upper half section 37 and the blade ring lower half section 38, and the amount of the change in the clearance in the vertical direction between the inner circumferential surface of the blade ring 34 and the outer circumferential surface of the rotor (rotating shaft) 12, which is arranged inside the blade ring 34, is calculated.

[0024] The process for calculating the change in the blade ring clearance is handled by a control device. This control device is implemented, for example, by a central processing unit (CPU) or a microprocessing unit (MPU) executing various programs stored in a memory unit using RAM as a workspace. Furthermore, the control device is connected to an operator device, such as a keyboard, and an operator inputs various command or control signals to the control device using the operator device to perform the process of calculating the change in the blade ring clearance.

[0025] In the procedure for calculating the amount of the change in the clearance of the blade ring of the first embodiment, the amount of the change in clearance is predicted and calculated by using geometric calculation based on the following assumption from a back surface measurement when the blade ring 34 is disassembled. 1. Back surface measurement is a measurement in the horizontal direction in the vicinity of the mounting surfaces 37a, 37b, 38a and 38b. Therefore, a change in the back surface measurement coincides with a change in the radius of curvature. 2. The inclined mounting surfaces 38a and 38b, before the blade ring 34 is mounted, become the horizontal mounting surfaces 37a and 37b after mounting, and a uniform bending moment acts on the entire blade ring upper half section 37 or the entire blade ring lower half section 38. Therefore, deformation, rather than elliptical deformation, indicates that the radius of curvature is changed. Consequently, the neutral axes of the upper half section 37 and the lower half section 38 of the blade ring 34 maintain a perfect circle after the blade ring 34 is mounted. 3. The arc length of a first neutral axis after the bucket ring 34 has been fitted is the same as the arc length of a second neutral axis before the bucket ring 34 has been fitted.

[0026] At every step in Fig. Steps S11 to S15 are processes for the blade ring 34 in a first state, in which the blade ring upper half section 37 is connected to the blade ring lower half section 38. Furthermore, steps S16 to S20 are processes for the blade ring 34 in a second state, in which the blade ring upper half section 37 is removed from the blade ring lower half section 38.

[0027] As in Fig. As shown in Figure 4, in step S11, a cross-sectional shape of the blade ring 34 is determined. The cross-sectional shape of the blade ring 34 in the first state is determined from a design value of the blade ring 34 or a measured value of the blade ring 34 in the first state. In step S12, the first neutral axis of the blade ring 34 in the first state is calculated. In step S13, a first radius of curvature is calculated based on a first neutral axis VA1.

[0028] That is, as in Fig. As shown in Figure 5, the lower half section 38 of the blade ring 34 is supported by two support sections 39 and 40. Here, the first neutral axis VA1 is a position of a cross-section that exhibits no stress when a bending moment is generated with respect to the blade ring 34 in the first state. In this case, with support points 39a and 40a located on the first neutral axis VA1, the support sections 39 and 40 support the first neutral axis VA1 of the blade ring 34 in the first state. Here, the support points 39a and 40a of the support sections 39 and 40 are set with respect to the first neutral axis VA1. A first radius of curvature R1 of the first neutral axis VA1 is calculated.

[0029] Back to Fig. In step S14, the first neutral axis VA1 is drawn, and in step S15, the first measurement point is drawn. That is, as in Fig. Figure 5 shows the first neutral axis VA1, which runs through support sections 39 and 40, at points 39a and 40a. Support sections 39 and 40 at points 39a and 40a are the first measurement points.

[0030] Back to Fig. 4. In step S16, a back surface measurement of the blade ring 34 is recorded in the second state. That is, as in Fig. As shown in Figure 3, a back-surface measurement H2 is a horizontal length between an inner wall surface of the casing 31 (upper half section 32 and lower half section 33) and the support point 39b (40b) when the blade ring 34 is in the second state. In this case, the back-surface measurement H2 is obtained by taking the back-surface measurements on both sides of the blade ring 34 and averaging the back-surface measurements on both sides. A back-surface measurement H1 (to be described later) is a horizontal length between the inner wall surface of the casing 31 (upper half section 32 and lower half section 33) and the support point 39a (40a) when the blade ring 34 is in the first state, and is a design value or a measured value.

[0031] Back to Fig. In step S17, the magnitude of a change in the back surface measurement is calculated. That is, a displacement in the horizontal direction between the blade ring 34 in the first state and the blade ring 34 in the second state is recorded as the magnitude of the change in the back surface measurement. In other words, a deviation between the back surface measurement H1 of the blade ring 34 in the first state and the back surface measurement H2 of the blade ring 34 in the second state is calculated as the magnitude of a change ΔH in the back surface measurement. In this case, a second measurement point is drawn in step S18. In step S19, a second radius of curvature is calculated. In step S20, the second neutral axis is drawn.

[0032] That is, as in Fig. As shown in Figure 5, support points 39b and 40b, the second measurement points, are drawn with respect to the first neutral axis VA1 of the blade ring in the first state, and support points 39a and 40a, the first measurement points, are drawn in steps S14 and S15 based on the magnitude of the change ΔH of the back surface measurement. A second radius of curvature R2, where the arc lengths of support points 39a and 40a and the arc lengths of support points 39b and 40b at the first neutral axis VA1 are equal, is calculated, and the second neutral axis VA2 is drawn.

[0033] With renewed reference to Fig. In step S21, the rate of change of the game is calculated. That is, as in Fig. As shown in Figure 5, the amount of change ΔH of the back surface measurement is output as the displacement amount in the horizontal direction with respect to the blade ring 34 as the amount of a change in the clearance ΔS. <Verfahren zum Anpassen von Position von Schaufelring>

[0034] Fig. Figure 6 is a flowchart showing a procedure for adjusting the position of the paddle ring.

[0035] As in Fig. 2 and Fig. As shown in Figure 6, the upper housing section 32 is removed in step S31. In step S32, the back surface measurement H1 of the blade ring 34 is measured. In step S33, the upper blade ring section 37 is removed. In step S34, the back surface measurement H2 of the blade ring 34 is measured. Then, in step S35, the amount of the change in clearance ΔS caused by the change in the radius of curvature is determined by performing the process described above (steps S11 to S21). When the upper blade ring section 37 is installed, the position of the blade ring 34 in the vertical direction is adjusted using the amount of the change in clearance ΔS in step S36. [Second embodiment]

[0036] Fig. Figure 7 is a view describing a method for calculating the amount of a change in the clearance of the paddle ring of a second embodiment, and Fig. Figure 8 is an enlarged view to describe the procedure for calculating the amount of change in the paddle ring's play.

[0037] As in Fig. Figure 7 shows that in the first embodiment, a case is described in which, while the support points 39a and 40a are located on the first neutral axis VA1, the support sections 39 and 40 support the first neutral axis VA1 of the blade ring 34 in the first state. In this case, however, if the support points 39a and 40a (39b and 40b) of the blade ring 34 are separated from the neutral axis, it is necessary to take into account a displacement of the blade ring 34 in the vertical direction caused by the assembly.

[0038] When the support point 40b is located on an outer circumferential surface of the blade ring lower half section 38 in the second state, a distance L is set to a point VA2a, which is located at the shortest distance from the support point 40b to the second neutral axis VA2. Similarly, when the blade ring lower half section 38 is in the first state, if the support point 40a is located on the outer circumferential surface of the blade ring lower half section 38, the distance L is set to a point VA1a, which is located at the shortest distance from the support point 40a to the first neutral axis VA1.

[0039] In this case, as in Fig. Figure 8 shows that, in the second state, a second connecting line of distance L connects the support point 40b on the outer circumferential surface of the blade ring lower half section 38 and the point VA2a on the second neutral axis VA2 with respect to a horizontal line, a line inclined at an angle α2. Furthermore, in the first state, a first connecting line of distance L connects the support point 40a on the outer circumferential surface of the blade ring lower half section 38 and the point V12a on the first neutral axis VA1 with respect to the horizontal line, a line inclined at an angle α1.Here is a relationship between the angles α1 and α2 of the connecting lines α1 < α2, since the angles of the fastening surfaces 38a and 38b change between the blade ring lower half section 38 in the first state and the blade ring lower half section 38 in the second state.

[0040] Consequently, the vertical distance S2 between support point 40b and point VA2a in the lower blade ring section 38 differs in the second state, as does the vertical distance S1 between support point 40a and point VA1a in the lower blade ring section 38 in the first state. That is, the relationship between distances S1 and S2 is S1 > S2, and when the lower blade ring section 38 is changed from the second state to the first state, the lower blade ring section 38 moves upwards in the vertical direction, and the clearance S in the vertical direction in the lower section of the outer circumferential surface of the rotor 12 and the inner circumferential surface of the blade ring 34 is reduced and narrowed.

[0041] If the distance L between the support points 40a and 40b, which are located on the outer circumferential surface of the blade ring lower half section 38, and the neutral axes VA1 and VA2, the angle α2 of the second connecting line (support point 40b - point VA2a) with respect to the horizontal line and the amount of the change of an angle Δα from the angle α2 to the angle α1 are defined, the amount of a change in the clearance (correction value of the amount of the change in the clearance) ΔSa can be calculated by the following equation. ΔSa=S1−S2=L×{sin(α2+Δα)−sinα2]

[0042] In Fig. 5 In the first embodiment, the amount of the change of the angle Δα can be calculated from an angle formed by a tangent line of the first neutral axis VA1 at the support points 39a and 40a of the blade ring 34 in the first state and a tangent line of the second neutral axis VA2 at the support points 39b and 40b of the blade ring 34 in the second state.

[0043] Fig. Figure 9 is a flowchart showing a method for calculating the magnitude of a change in the clearance of a paddle ring of a second embodiment.

[0044] As in Fig. As shown in Figure 9, in step S31 the upper housing half section 32 is removed. In step S32, the back surface measurement H1 of the blade ring 34 is measured. In step S33, the upper blade ring half section 37 is removed. In step S34, the back surface measurement H2 of the blade ring 34 is measured. Then, in step S35, the amount of the change in clearance ΔS caused by the change in the radius of curvature is determined by performing the process described above (steps S11 to S21).

[0045] Furthermore, in step S41, the amount of the change in clearance ΔSa caused by the distance between the support point and the neutral axis is determined by performing the process described above. In step S42, the amount of the change in clearance ΔS is corrected by the amount of the change in clearance ΔSa; that is, the amount of the change in clearance ΔS is corrected by recalculating and adding the amount of the change in clearance ΔSa to the amount of the change in clearance ΔS. Then, when the blade ring upper half section 37 is mounted, in step S36 the position of the blade ring 34 in the vertical direction is adjusted using the amount of the change in clearance ΔS. [Operational effects of the present embodiment]

[0046] A method for calculating the amount of change in the clearance of the blade ring according to a first aspect comprises a step of capturing the displacement amount in the horizontal direction of the blade ring 34 in the first state, in which the blade ring upper half section 37 is connected to the blade ring lower half section 38, and in the second state, in which the blade ring upper half section 37 has been removed from the blade ring lower half section 38; a step of calculating the second neutral axis of the blade ring 34 in the second state based on the displacement amount; and a step of calculating the amount of change in clearance between the first state and the second state by comparing the first neutral axis of the blade ring 34 in the first state with the second neutral axis.

[0047] According to the procedure for calculating the amount of change in the blade ring clearance in the first aspect, and assuming that the change in the back surface measurement corresponds to the change in the radius of curvature, that the neutral axes of the blade ring upper half section 37 and the blade ring lower half section 38 maintain a perfect circle after the blade ring 34 has been mounted, and that the arc length of the first neutral axis after the blade ring 34 has been mounted corresponds to the arc length of the second neutral axis before the blade ring 34 has been mounted, it is possible to estimate the amount of change in the clearance in the vertical direction between the outer circumferential surface of the rotor 12 and the inner circumferential surface of the blade ring 34. Therefore, improved machinability of the housing assembly work can be achieved.

[0048] According to the procedure for calculating the amount of change in the blade ring clearance under a second aspect, the first neutral axis of the blade ring 34 in the first state is further calculated based on the design value or the measured value of the blade ring 34, and the second neutral axis of the blade ring 34 in the second state is calculated based on the measured value of the blade ring 34. In this way, the first and second neutral axes can be easily calculated.

[0049] According to the procedure for calculating the amount of change in the blade ring clearance in a third aspect, the procedure for calculating the amount of change in the blade ring clearance according to the first aspect or the second aspect further assumes that the two support points 39a, 39b, 40a and 40b for supporting the blade ring 34 from below are assumed to pass through the first neutral axis or the second neutral axis. In this way, the amount of change in clearance can be easily estimated.

[0050] According to the procedure for calculating the amount of change in the blade ring clearance for a fourth aspect, the correction value for the amount of change in the blade ring clearance according to one of the first to third aspects is further calculated based on the angle of the first connecting line that links the support points 39a, 39b, 40a, and 40b for supporting the blade ring 34 from below and the first neutral axis with the shortest length, and the angle of the second connecting line that links the support points 39a, 39b, 40a, and 40b and the second neutral axis with the shortest length. The amount of change in clearance is then corrected by applying this correction value. In this way, the amount of change in clearance can be calculated with high accuracy.

[0051] According to the procedure for adjusting the position of the blade ring at a fifth aspect, when the blade ring upper half section 37 is mounted with the blade ring lower half section 38, the position of the blade ring 34 in the vertical direction is adjusted based on the amount of the change in clearance, which is calculated by the procedure for calculating the amount of the change in clearance of the blade ring. In this way, the position of the blade ring 34 can be adjusted with high precision. Reference symbol list 10 Steam turbine (lathe) 11 cases 12 Rotor (rotating shaft) 13 Stator blade 14 Rotor blade 31 cases 32 Housing upper half section 33 Housing lower half section 34 shovel ring 35 Outer ring 36 inner ring 37 Bucket ring upper half section 38 Bucket ring lower half section 39, 40 Support section 39a, 39b, 40a, 40b base QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 5501875

[0004] < / schaufelring> < / dampfturbine>

Claims

[1] Method for calculating the amount of a change in the clearance of a blade ring, wherein a blade ring having a ring shape is configured by joining a blade ring upper half section and a blade ring lower half section, and the amount of the change in the clearance in a vertical direction between an inner circumferential surface of the blade ring and an outer circumferential surface of a rotating shaft arranged inside the blade ring is calculated, the method comprising: a step of capturing a displacement amount in a horizontal direction of the blade ring in a first state in which the blade ring upper half section is connected to the blade ring lower half section, and a second state in which the blade ring upper half section is removed from the blade ring lower half section; a step of calculating a second neutral axis of the blade ring in the second state based on the displacement magnitude; and a step of calculating the magnitude of the change in the clearance between the first state and the second state by comparing a first neutral axis of the paddle ring in the first state with the second neutral axis. [2] Method for calculating the amount of a change in the clearance of a blade ring according to claim 1, wherein the first neutral axis of the blade ring in the first state is calculated on the basis of a design value or a measured value of the blade ring and the second neutral axis of the blade ring in the second state is calculated on the basis of the measured value of the blade ring. [3] Method for calculating the amount of a change in a clearance of a blade ring according to claim 1 or 2, wherein it is assumed that two support points for supporting the blade ring from below pass through the first neutral axis or the second neutral axis. [4] Method for calculating the amount of a change in the clearance of a blade ring according to claim 1, wherein a correction value of the amount of the change in the clearance in the vertical direction between the first state and the second state is calculated on the basis of an angle of a first connecting line connecting a support point for supporting the blade ring from below and the first neutral axis with a shortest length, and an angle of a second connecting line connecting the support point and the second neutral axis with a shortest length, and the amount of the change in clearance is corrected by using the correction value of the amount of the change in clearance. [5] Method for adjusting the position of a blade ring, wherein, when a blade ring upper half section is mounted with a blade ring lower half section, the position of the blade ring is adjusted in a vertical direction on the basis of the amount of the change in clearance calculated by the method for calculating the amount of a change in clearance of a blade ring according to claim 1.

Images