Flange strain measuring jig

Abstract

To provide a flange strain measuring tool capable of highly accurately and easily measuring the surface strain of a flange functioning as a pipe joint.SOLUTION: The disc-shaped jig body 2 positioned on the flange by the positioning device is provided with a plurality of measurement holes 12a to 12c at intervals in the circumferential direction in the first facing annular portion 22 facing the target surface portion of the flange in the positioned state. The flange strain measuring jig 1 according to the present invention can easily and stably measure surface strain of a target surface portion of a flange by inserting a gauge head of a dial gage into each of the measurement holes 12a to 12c of the jig body 2 in a state where the jig body 2 is positioned on the flange.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a flange distortion measuring jig for measuring surface distortion of a flange that functions as a pipe joint. [Background technology]

[0002] A jig for measuring the surface distortion of a flange has been proposed, for example, in Patent Document 1. Patent Document 1 discloses a configuration including four support members attached to the peripheral edge of the flange, two shafts supported by the support members, a center block placed at the center of the flange by the shafts, and a rotation unit rotatably provided on the center block, in which a dial gauge is held on the rotation unit and rotated to measure the surface distortion of the flange. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-127667 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional configuration of Patent Document 1, the rotating unit is rotatably supported by a shaft supported by a support member. Therefore, due to tolerances set for the connection between the support member and the shaft, the connection between the shaft and the center block, and the connection between the center block and the rotating unit, rattles are likely to occur, which may result in measurement errors. Furthermore, there is a risk of measurement errors occurring depending on how the force that rotates the rotating unit is applied. For these reasons, it is difficult to accurately and stably measure the surface strain of a flange with the conventional configuration.

[0005] The present invention proposes a flange distortion measuring jig that can measure the surface distortion of a flange with high accuracy and stability. [Means for solving the problem]

[0006] The present invention is a flange strain measuring jig for measuring surface strain of an annular target surface portion defined on the surface of a flange that functions as a pipe joint, characterized in that it comprises a jig main body that is positioned with respect to the target surface portion of the flange, the jig main body having an annular opposing ring portion that faces the target surface portion in a state in which it is positioned with respect to the target surface portion, and the opposing ring portion has a plurality of measurement holes formed therein at intervals around the circumferential direction of the opposing ring portion, through which measuring probes of a measuring instrument that measures the surface strain can be inserted. The target surface of the flange may be a part of the surface or the entire surface. The former target surface may include, for example, at least a portion of the surface that contacts an annular packing interposed between the flanges to be connected. Furthermore, the present invention is preferably configured to include a positioning means for positioning the jig body.

[0007] In this configuration, by positioning the jig body, the multiple measurement holes provided in the opposing ring portions are positioned directly above the target surface portion of the flange, and the surface strain of the target surface portion can be measured by inserting the probes of a measuring instrument into these measurement holes. In addition, since the surface strain can be measured by inserting the probes into the measurement holes when the jig body is in the positioned state, the measurement of the surface strain can be easily performed, and since the measurement can be performed without applying unnecessary force to the jig body, the measurement can be performed with high accuracy.

[0008] In the flange distortion measuring jig of the present invention described above, a configuration is proposed in which the multiple measurement holes include measurement holes that are at different distances from a reference position located on the center line of the flange in the positioned state.

[0009] In this configuration, by measuring the surface strain using the measurement holes in the opposing ring portions, it is possible to measure the circumferential surface strain and the radial surface strain on the target surface portion of the flange. Here, since a flange, which is a pipe joint, can generally have distortion not only in the circumferential direction but also in the radial direction, in order to know the surface distortion more accurately, it is necessary to measure the surface distortion in both the circumferential direction and the radial direction. In the conventional configuration described above, in order to change the radial position of the flange and perform measurements, it is necessary to change the mounting position of the measuring instrument, which makes the device complicated and requires a lot of time and effort to change the mounting position. In contrast, in the present configuration, by using each measurement hole as described above, the surface distortion in the circumferential direction and the radial direction of the target surface can be measured easily and with high accuracy.

[0010] In the flange distortion measuring jig of the present invention described above, the jig body is provided with a plurality of holding protrusions that protrude toward the flange in the positioning state, and a configuration is proposed in which the holding protrusions abut against the surface of the flange in the positioning state, creating a predetermined gap between the opposing surface of the flange and the jig body.

[0011] In this configuration, the target surface portion of the flange and the opposing ring portion of the jig body are positioned via a gap, and by inserting the measuring probe of the measuring instrument into the measurement hole, the measurement accuracy of the surface distortion by the measuring instrument can be further stabilized.

[0012] In the flange distortion measurement jig of the present invention described above, a configuration is proposed in which the jig body is formed with a plurality of concentric opposing ring portions that, in the positioned state, face the respective target surfaces of the plurality of flanges having different diameters, and each opposing ring portion is formed with a plurality of measurement holes spaced apart in the circumferential direction. Here, the different diameters preferably represent the inner diameters of the flanges.

[0013] With this configuration, the surface distortion of each target surface portion can be measured for multiple flanges corresponding to each opposing ring portion, and the surface distortion of each target surface portion can be measured easily and stably with high accuracy.

[0014] In the flange distortion measuring jig of the present invention described above, it is proposed that the jig body has a configuration in which the measurement holes of each opposing ring portion are arranged radially along the radial direction of the flange in the positioned state.

[0015] With this configuration, when measuring flanges of different diameters, it is easy to insert the measuring probes of the measuring instrument into the respective measurement holes lined up in the circumferential direction, thereby improving the workability of the measurement work.

[0016] In the flange distortion measuring jig of the present invention described above, a configuration is proposed in which an identification display portion is provided on the surface of the jig body to identify the measurement holes belonging to each opposing ring portion.

[0017] In this configuration, the identification display portion makes it easy to distinguish the measurement holes belonging to each opposing ring portion, so that when measuring the surface strain of the flange, the operator can correctly select the measurement hole through which to insert the probe of the measuring instrument. This prevents the probe from being mistakenly inserted into a measurement hole that does not correspond to the flange to be measured, and overall makes the measurement work more efficient. [Effects of the Invention]

[0018] According to the flange distortion measuring jig of the present invention, by positioning the jig body and inserting the probe of the measuring instrument into each measurement hole, the surface distortion of the target surface of the flange can be measured with high accuracy, and the measurement can be performed easily and stably. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a plan view of a flange distortion measuring jig 1 of the present embodiment. [Figure 2]FIG. 2 is a bottom view of the flange distortion measuring jig 1. [Figure 3] 1 is a vertical cross-sectional view showing a state in which the flange distortion measuring jig 1 is attached to the flange 102 and positioned. [Figure 4] 2 is a plan view showing a first opposing ring portion 22 of the jig body 2 of the flange distortion measurement jig 1. FIG. [Figure 5] 2A is a plan view showing the second opposing ring portion 23 of the jig body 2, and FIG. 2B is a plan view showing the third opposing ring portion 24 of the jig body 2. FIG. [Figure 6] 1A is a plan view showing a fourth opposing ring portion 25 of the jig body 2, and FIG. 1B is a plan view showing a fifth opposing ring portion 26 of the jig body 2. FIG. [Figure 7] 2 is an enlarged plan view showing a part of the jig body 2. FIG. [Figure 8] 2A and 2B are a bottom view and a cross-sectional view taken along line XX, respectively, of the jig body 2. FIG. [Figure 9] 10 is a perspective view showing a state in which the jig body 2 is separated from the flange 102. FIG. [Figure 10] 10 is an explanatory diagram showing a state in which a probe 93 of a dial gauge 91 is set in measurement holes 12a to 12c of a first opposing ring portion 22. FIG. [Figure 11] 10 is an explanatory diagram showing a state in which a probe 93 of a dial gauge 91 is set in measurement holes 13a to 13c of a second opposing ring portion 23. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to the accompanying drawings. The flange strain measuring jig 1 of this embodiment is a jig used to measure the surface strain of a flange 102 that functions as a pipe joint using a dial gauge 91, and as will be described later, can measure the surface strain of an annular target surface portion 105 defined on the surface of the flange 102 as a measurement target. As shown in FIGS. 1 to 3 , this flange strain measuring jig 1 includes a disk-shaped jig main body 2, a positioning device (positioning means) 3 that positions the jig main body 2 to the flange 102 of a pipe 101, and a fixing device (fixing means) 4 that fixes the jig main body 2 to the flange 102. In this embodiment, three fixing devices 4 are provided at intervals around the circumferential direction of the jig main body 2.

[0021] In this embodiment, the front-back direction is defined as the back side in the direction toward the flange 102 and the front side in the opposite direction when the flange distortion measuring jig 1 is fixed to the flange 102. The inside-outside direction is defined along the radial direction of the jig body 2, and the direction toward the center P of the jig body 2 is defined as the inside and the opposite direction is defined as the outside.

[0022] The pipe 101 is used for gas pipes, water pipes, etc., and, as shown in Figures 3 and 9, comprises a circular pipe 103 and an annular flange 102 provided at the end of the circular pipe 103. The circular pipe 103 and flange 102 are made of steel, and the pipe 101 is formed by welding the flange 102 to the end of the circular pipe 103, with the flange 102 being a so-called welded joint. A plurality of insertion holes 104, through which connecting bolts (not shown) are inserted, are formed at intervals in the circumferential direction in the outer periphery of the flange 102. These pipes 101 are connected to each other by butting the flanges 102 of the pipes 101 together and fastening the bolts and nuts inserted into the respective insertion holes 104. Here, an annular rubber packing (not shown) is interposed between the flanges 102, 102, on the inner periphery of the flange 102, which is inside the outer periphery where the insertion hole 104 is provided. In this embodiment, the inner periphery of the surface of the flange 102 where the packing is arranged is the target surface 105 where the surface strain is measured by the flange strain measuring jig 1. The size (inner diameter dimension and outer diameter dimension) of this target surface 105 is determined according to the size (diameter dimension) of the flange 102.

[0023] 1 to 3, the jig body 2 of the flange distortion measuring jig 1 is formed into a disk shape from a metal flat plate and has a circular opening 11 in the center. The positioning device 3 is fixed to this opening 11, and the three fixing devices 4 are attached to the surface of the jig body 2.

[0024] The positioning device 3 includes a handle portion 51 disposed on the front side of the jig body 2, a device body portion 52 that accommodates the shaft portion of the handle portion 51, a fixing portion 53 that fixes the device body portion 52 to the opening 11, and support rod portions 54 that protrude outward from the device body portion 52 at equal intervals in the circumferential direction. Rotating the handle portion 51 causes each support rod portion 54 to move back and forth in its longitudinal direction. By abutting the tip end 55 of each support rod portion 54 against the inner circumferential surface of the pipe 101, the center of the opening 11 (center P of the jig body 2) can be aligned with the center line L of the pipe 101 (circular pipe 103 and flange 102). The state in which the center P of the jig body 2 is aligned with the center line L of the flange 102 by the positioning device 3 corresponds to the positioning state according to the present invention. Since a conventionally known configuration can be used for the positioning device 3, details thereof will be omitted.

[0025] The fixing device 4 includes a base 61 provided on the surface of the jig body 2 so as to be movable forward and backward in the radial direction of the jig body 2, a protruding rod 62 protruding from the outer end of the base 61 toward the rear of the jig body 2, a support rod 63 provided at the rear end of the protruding rod 62, and a pressure contact portion 64 protruding from the inner end of the support rod 63 toward the front. An operating portion 65 is provided at the outer end of the base 61 for moving the protruding rod 62 in the front-to-rear direction of the jig body 2. The fixing device 4 further includes a positioning means (not shown) for converting the base 61 between a state in which it is movable forward and backward in the radial direction of the jig body 2 and a state in which it is unable to move, and the support rod 63 is provided so as to be movable forward and backward in its longitudinal direction so that it can be positioned at a desired forward and backward position.

[0026] 3, such fixing device 4 can fix the jig body 2 to the flange 102 by operating the operating part 65 to press the pressure contact part 64 against the back surface of the flange 102 in a state where the jig body 2 is positioned on the surface of the flange 102 by the positioning device 3 (positioned state). In this embodiment, the fixing devices 4 provided at three locations around the circumferential direction of the jig body 2 can fix the jig body 2 in a substantially balanced manner in the circumferential direction.

[0027] As shown in FIGS. 4 to 7, the jig body 2 is formed with a plurality of measurement holes 12a, b, c to 16a, b, c. The measurement holes 12a, b, c to 16a, b, c penetrate the jig body 2 from front to back in a direction perpendicular to the surface of the jig body 2, and are formed with a diameter that allows a probe 93 of a dial gauge 91 to be inserted therethrough (see FIGS. 10 and 11). The dial gauge 91 is a typical spindle type, and can measure dimensional accuracy by abutting the probe 93 protruding downward from a stem 92 against a measurement target. In this embodiment, the stem 92 is supported by the hole edges of the measurement holes 12a, b, c to 16a, b, c, and the probe 93 inserted through the measurement holes 12a, b, c to 16a, b, c against a target surface 105 of the flange 102, thereby measuring the surface distortion of the target surface 105.

[0028] The measurement holes 12a, b, c to 16a, b, c are provided with first to fifth opposing ring portions 22 to 26 that are arranged opposite the target surface portion 105 of the flange 102 when the jig body 2 is positioned on the flange 102 by the positioning device 3. Here, there are multiple types of pipes 101, each with a different inner diameter dimension of the circular pipe 103, and flanges 102 of dimensions and shapes corresponding to these inner diameter dimensions are joined to the circular pipe 103. Different sizes of packing are also applied to be interposed between the flanges 102, depending on the inner diameter dimensions of the circular pipe 103 (and flanges 102). Therefore, the diameter dimensions (inner diameter dimension and outer diameter dimension) of the target surface portion 105 of the flange 102 differ depending on the size (inner diameter dimension) of the pipe 101. In order to be able to measure the surface strain of such target surface portions 105 with different diameter dimensions, the jig body 2 of this embodiment has the measurement holes 12a, b, c to 16a, b, c formed in the first to fifth opposing ring portions 22 to 26 that face each target surface portion 105 in the positioned state.

[0029] 4 to 6, the jig body 2 of this embodiment is provided with first to fifth opposing ring portions 22 to 26 that respectively face the five types of target surface portions 105 having different diameters. These first to fifth opposing ring portions 22 to 26 and the opening 11 are provided concentrically, and are disposed opposite the target surface portions 105 of the flange 102 in a state positioned by the positioning device 3.

[0030] As shown in Fig. 4, nine measurement holes 12a to 12c are formed at intervals in the circumferential direction in the first opposing ring portion 22, which has the largest diameter in the jig body 2. Here, as shown in Fig. 7, the first opposing ring portion 22 is formed with measurement hole 12a located at a distance r1 from the center P of opening 11, measurement hole 12b located at a distance r2 from the center P, and measurement hole 12c located at a distance r3 from the center P. These distances r1, r2, and r3 are different from one another, and have a relationship of r1 > r2 > r3. In this embodiment, three of each of these measurement holes 12a to 12c are formed in the first opposing ring portion 22.

[0031] As shown in Fig. 5(A), nine measurement holes 13a to 13c are formed in second opposing ring portion 23 at intervals in the circumferential direction. Here, as shown in Fig. 7, second opposing ring portion 23 is formed with measurement hole 13a located at a distance s1 from center P, measurement hole 13b located at a distance s2 from center P, and measurement hole 13c located at a distance s3 from center P, and three of each of these measurement holes 13a to 13c are provided. Distances s1, s2, and s3 are different from one another (s1>s2>s3).

[0032] As shown in Fig. 5(B), nine measurement holes 14a to 14c are formed in third opposing ring portion 24 at intervals in the circumferential direction. Here, as shown in Fig. 7, third opposing ring portion 24 is formed with measurement hole 14a located at a distance t1 from center P, measurement hole 14b located at a distance t2 from center P, and measurement hole 14c located at a distance t3 from center P, and three of each of these measurement holes 14a to 14c are provided. The distances t1, t2, and t3 are different from one another (t1>t2>t3).

[0033] As shown in Fig. 6(A), nine measurement holes 15a to 15c are formed in fourth opposing ring portion 25 at intervals in the circumferential direction. Here, as shown in Fig. 7, fourth opposing ring portion 25 is formed with measurement hole 15a located at a distance w1 from center P, measurement hole 15b located at a distance w2 from center P, and measurement hole 15c located at a distance w3 from center P, and three of each of these measurement holes 15a to 15c are provided. The distances w1, w2, and w3 are different from one another (w1>w2>w3). In this embodiment, since the outer periphery of the fourth opposing ring portion 25 overlaps with the inner periphery of the third opposing ring portion 24 (see Figures 5(B) and 6(A)), the measurement hole 15a of the fourth opposing ring portion 25 and the measurement hole 14c of the third opposing ring portion 24 are shared by a single measurement hole (distance w1 = distance t3).

[0034] As shown in Fig. 6(B), nine measurement holes 16a to 16c are formed in fifth opposing ring portion 26 at intervals in the circumferential direction. Here, as shown in Fig. 7, fifth opposing ring portion 26 is formed with measurement hole 16a located at a distance k1 from center P, measurement hole 16b located at a distance k2 from center P, and measurement hole 16c located at a distance k3 from center P, and three of each of these measurement holes 16a to 16c are provided. The distances k1, k2, and k3 are different from one another (k1>k2>k3).

[0035] In the jig body 2 of this embodiment, the measurement holes 12a, b, c to 16a, b, c provided in each of the opposing ring portions 22 to 26 are arranged radially from the center P (FIGS. 4 to 7).

[0036] Furthermore, identification symbols 17a-17f are provided on the jig body 2 at locations adjacent to each of the measurement holes 12a, b, c-16a, b, c, respectively, so that the opposing ring portions 22-26 to which each of the measurement holes 12a, b, c-16a, b, c belongs can be identified by the identification symbols 17a-17f. Specifically, as shown in FIGS. 4-7, identification symbols 17a are provided at locations adjacent to each of the measurement holes 12a-12c on the first opposing ring portion 22. Identification symbols 17b are provided at locations adjacent to each of the measurement holes 13a-13c on the second opposing ring portion 23. Identification symbols 17c or 17f are provided at locations adjacent to each of the measurement holes 14a-14c on the third opposing ring portion 24, and identification symbols 17d or 17f are provided at locations adjacent to each of the measurement holes 15a-15c on the fourth opposing ring portion 25. Here, since measurement hole 14c of third opposing ring portion 24 and measurement hole 15a of fourth opposing ring portion 25 are common, identification symbol 17f is provided to indicate that they belong to both third opposing ring portion 24 and fourth opposing ring portion 25. Furthermore, identification symbol 17e is provided at locations adjacent to measurement holes 16a to 16c of fifth opposing ring portion 26, respectively.

[0037] Furthermore, the jig body 2 is provided with a plurality of holding protrusions 29 that protrude rearward from the rear surface thereof. The holding protrusions 29 are intended to position the jig body 2 on the surface of the flange 102 via a gap, and are arranged at a plurality of positions at different distances from the center P of the jig body 2. These holding protrusions 29 allow the jig body 2 to be positioned from the surface of the flange 102 via a gap while fixed by the fixing device 4.

[0038] Next, a mode of measuring the surface strain of the flange 102 using the flange strain measuring jig 1 of this embodiment will be described. First, the flange distortion measuring jig 1 is fixed to the flange 102 in a positioned state in which the center P of the jig body 2 and the center line L of the flange 102 are aligned (see FIG. 3). More specifically, the holding protrusion 29 of the jig body 2 is brought into contact with the surface of the flange 102, and the center P of the jig body 2 is aligned with the center line L of the flange 102 by the positioning device 3, and in this aligned, positioned state, the flange distortion measuring jig 1 is fixed to the flange 102 by the fixing device 4.

[0039] For example, if the flange 102 has a target surface portion 105 facing the first opposing ring portion 22 of the jig body 2, the positioning device 3 and the fixing device 4 hold the first opposing ring portion 22 of the jig body 2 in a positioned state facing the target surface portion 105 of the flange 102 with a gap therebetween, as described above. In this state, the dial gauge 91 is set in one of the measurement holes 12a to 12c in the first opposing ring portion 22 of the jig body 2. Here, as described above, the dial gauge 91 has a stem 92 supported by the hole edges of the measurement holes 12a to 12c, and the probe 93 inserted through the measurement holes 12a to 12c is brought into contact with the target surface portion 105 of the flange 102 (see FIG. 10 ). When the dial gauge 91 is set in this manner, the measurement value of the dial gauge 91 is reset.

[0040] 10, the reset dial gauge 91 is sequentially set in all of the measurement holes 12a to 12c belonging to the first opposing ring portion 22 of the jig body 2 and measurements are taken, and the surface strain of the target surface portion 105 of the flange 102 is measured based on the measurement values ​​taken in each of the measurement holes 12a to 12c. Here, since the first opposing ring portion 22 has measurement holes 12a to 12c that are spaced apart in the circumferential direction and are located at different distances r1, r2, r3 from the center P, by setting the dial gauge 91 in each of these measurement holes 12a to 12c and taking measurements, the surface strain of the target surface portion 105 in the circumferential and radial directions can be measured.

[0041] Furthermore, even when the flange 102 is configured to include a target surface portion 105 facing the second opposing ring portion 23 of the jig body 2, the second opposing ring portion is held in a positioned state facing the target surface portion 105 via a gap by the positioning device 3 and the fixing device 4, similar to the case of the first opposing ring portion 22 described above. Then, in the positioned state, a dial gauge 91 is set in one of the measurement holes 13a to 13c in the second opposing ring portion 23 to reset the measurement value, and then, as shown in FIG. 11, the dial gauge 91 is set in each of the measurement holes 13a to 13c in turn to measure the surface strain.

[0042] Similarly, even when the flange 102 is configured to include a target surface portion 105 that faces the third to fifth opposing ring portions 24 to 26, it is possible to measure the surface strain of the target surface portion 105. Even when the flange 102 has different diameters, the surface strain of the target surface portion 105 can be measured by positioning any of the first to fifth opposing ring portions 22 to 26 of the jig body 2 so that they face the target surface portion 105.

[0043] As described above, the flange distortion measuring jig 1 of this embodiment allows for easy and stable measurement of the surface distortion of each target surface 105 of a flange 102 having different diameters by setting the probe 93 of the dial gauge 91 in the measurement holes 12a, b, c to 16a, b, c corresponding to each target surface 105. Furthermore, since the jig body 2 has a plurality of measurement holes 12a, b, c to 16a, b, c at different radial distances provided in the circumferential direction, each of the opposing ring portions 22 to 26, it is possible to measure the surface distortion of the target surface 105 in both the circumferential and radial directions, improving measurement accuracy. Furthermore, in the configuration of this embodiment, when the jig body 2 is positioned and fixed to the flange 102, the holding protrusion 29 provides a gap between the jig body 2 and the surface of the flange 102, allowing the probe 93 of the set dial gauge 91 to stably abut against the surface of the target surface 105, thereby enabling stable and highly accurate measurement of the surface distortion.

[0044] In the above-described embodiment, the first to fifth opposing ring portions of the jig body 2 correspond to the opposing ring portions according to the present invention. The center P of the jig body 2 corresponds to the reference position according to the present invention. The identification symbols 17a to 17f correspond to the identification display portions according to the present invention. The dial gauge 91 corresponds to the measuring instrument according to the present invention.

[0045] The present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present invention. In the above-described embodiment, the jig body is configured to have first to fifth opposing ring portions (measurement holes) corresponding to five types of flanges (target surfaces) with different diameters, respectively. However, this is not limiting, and the number of opposing ring portions provided on the jig body can be changed as appropriate. For example, it is possible to have two opposing ring portions facing two types of flanges with different diameters, or seven opposing ring portions facing seven types of flanges with different diameters, respectively. Alternatively, the jig body may be configured to have only one opposing ring portion.

[0046] In the above-described embodiment, nine measurement holes are provided in each of the opposing ring portions, but this is not a limitation and the number of measurement holes provided in each opposing ring portion can be changed as appropriate. Also, in the embodiment, the same number of measurement holes are provided in all opposing ring portions, but this is not a limitation and each opposing ring portion can have a different number of measurement holes. For example, opposing ring portions with larger diameters may have more measurement holes than opposing ring portions with smaller diameters.

[0047] In the above-described embodiment, each opposing ring portion is provided with three measurement holes at different distances from the center of the jig body, three on each side (a total of nine holes), but this is not limiting, and the number of measurement holes at different distances can be changed as appropriate. For example, each opposing ring portion may be provided with a plurality of measurement holes at different distances (two or four holes each), with two or five measurement holes at different distances. Furthermore, the number of measurement holes at different distances may differ between opposing ring portions.

[0048] The above-described embodiment is configured such that a common measurement hole is provided in the fourth opposing ring portion and the fifth opposing ring portion, but this is not limited to this, and even if the distance from the center of the jig body is approximately the same, it is also possible to provide separate measurement holes instead of a common measurement hole.

[0049] In the above-described embodiment, identification symbols are provided adjacent to the measurement holes belonging to each opposing ring portion, but this is not limiting and the identification symbols can be changed as appropriate. For example, numbers or letters, or different colored figures or letters, etc., may be used. Furthermore, instead of identification symbols, each opposing ring portion may be color-coded so that the measurement holes belonging to each opposing ring portion can be distinguished.

[0050] The above-described embodiment is a configuration equipped with a positioning device that positions the flange or the inner surface of the circular pipe as a reference, but the present invention is not limited to this. It is also possible to employ a positioning device that positions the flange (or the circular pipe) as a reference, or a positioning device that positions the flange using an insertion hole provided in the flange.

[0051] The above-described embodiment is configured to have a positioning device and a fixing device, but this is not limiting and a configuration may be adopted in which a single device is provided with both a positioning function and a fixing function.

[0052] Although the above-described embodiment is configured with a disk-shaped jig body, the shape of the jig body is not limited to this and can be changed as appropriate. For example, the jig body may be a polygonal flat plate such as a square or pentagonal plate, or may be an elliptical flat plate. [Explanation of symbols]

[0053] 1 Flange distortion measurement jig 2 Jig body 3 Positioning device (positioning means) 12a~12c First measurement hole 13a~13c Second measurement hole 14a~14c Third measurement hole 15a~15c No. 4 measurement hole 16a~16c First measurement hole 17a~17f Identification symbol (identification display part) 22~26 Opposing ring 29 Holding protrusion 91 Dial gauge (measuring instrument) 93 Probe 102 flange 105 Target surface area L center line P center (reference position)

Claims

1. A flange distortion measurement jig for measuring surface distortion of an annular target surface portion defined on the surface of a flange that functions as a pipe joint, comprising: a jig body that is positioned relative to the target surface portion of the flange, The jig body is A flange distortion measurement jig comprising an annular opposing ring portion that faces the target surface portion in a positioned state relative to the target surface portion, and a plurality of measurement holes through which probes of a measuring instrument that measures the surface distortion are inserted are formed at intervals around the circumferential direction of the opposing ring portion.

2. 2. The flange distortion measuring jig according to claim 1, wherein the plurality of measurement holes include measurement holes that are at different distances from a reference position located on the center line of the flange in the positioned state.

3. 2. A flange distortion measuring jig as described in claim 1, characterized in that the jig body is provided with a plurality of holding protrusions that protrude toward the flange when in the positioned state, and the holding protrusions abut against the surface of the flange when in the positioned state, creating a predetermined gap between the opposing surface of the flange and the jig body.

4. The jig body is provided with a plurality of concentric opposing ring portions that face the respective target surface portions of the plurality of flanges having different diameters in the positioned state, 4. The flange distortion measuring jig according to claim 1, wherein a plurality of the measurement holes are formed in each of the opposing ring portions at intervals in the circumferential direction.

5. The jig body is 5. The flange distortion measuring jig according to claim 4, wherein the measurement holes in each of the opposing ring portions are arranged radially along the radial direction of the flange in the positioned state.

6. 5. The flange distortion measurement jig according to claim 4, wherein an identification marking portion for identifying the measurement hole belonging to each of the opposing ring portions is provided on the surface of the jig body.

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