Flange mounting jig unit and method for manufacturing flanged pipe structure

Abstract

To assist attachment of flanges to branch pipes which extend from a pipe body in various directions.SOLUTION: A flange attachment jig unit 1 according to the invention is used to attach a flange F to a pipe structure TF. The pipe structure includes a pipe body T1, a first branch pipe body T2, and a second branch pipe body T3. The flange includes a first flange F1, a second flange F2, and a third flange F3. The flange attachment jig unit has: first jigs 10, 20 for assisting attachment of the first flange; a second jig 30 for assisting attachment of the second flange; and a third jig 40 for assisting attachment of the third flange. When viewed in an axial direction of the pipe body, the second jig and the third jig are arranged at the side of the pipe body. The first jig may hold the pipe body through the first flange so that a first center axis of the first branch pipe body is parallel to a horizontal direction, and hold the pipe body through the first flange so that a second center axis of the second branch pipe body is parallel to the horizontal direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a flange installation jig unit and a method for manufacturing a flanged pipe structure. [Background technology]

[0002] Large-scale factory equipment (e.g., coke ovens and blast furnaces) that use large amounts of combustion gas have a complex piping structure formed by connecting pipe structures each made up of a main pipe corresponding to the main flow of gas and multiple branch pipes branching off from the main pipe. The pipe structures are connected to each other via flanges attached to the end of the main pipe. Furthermore, each branch pipe is connected to various branch pipes that supply gas to various locations within the equipment via flanges attached to the end of the branch pipe. Therefore, each branch pipe is connected to the main pipe in various directions when viewed in the axial direction of the main pipe.

[0003] To accommodate the supply of large amounts of gas, each pipe structure is large (for example, the main pipe is several meters long) and has a complex structure in which multiple branch pipes are connected. Therefore, even the slightest deviation in the mounting positions of the flanges relative to the main pipe and branch pipes (the circumferential and axial positions of the pipe body, the angle relative to the axial direction, etc.) increases the further away from those positions the greater the deviation becomes. Therefore, high precision is required for mounting the flanges to the pipe structure. For this reason, the flanges are welded to the pipe body while being aligned with the pipe body at the site where the pipe structure is to be installed.

[0004] Such a tube structure is made of a metal such as carbon steel. Therefore, the tube structure may be corroded by the gas itself or the moisture contained in the gas. Therefore, the inner surface of the tube structure may be coated with a resin such as a fluororesin.

[0005] If there is a gap (air gap) between the pipe structure or the inner surface of the flange, the expansion of air due to the heat of the gas will cause problems such as cracks and peeling of the coating. For this reason, the inner surfaces of the pipe structure and flanges are finished smoothly to avoid gaps and unevenness. Furthermore, the coating is prone to peeling off from the ends. Therefore, after the flange is attached to the pipe structure and the inner surface is smoothed, the coating is applied to the entire inner surface of the pipe structure so as to cover the welded parts between the flange and the pipe. In other words, the flange must be attached in advance to the pipe structure to which the coating is applied. For this reason, the attachment of flanges to main pipes and branch pipes requires high precision equivalent to that required for attachment by on-site alignment.

[0006] Techniques for attaching flanges to both ends of a pipe with high precision have been proposed (see, for example, Patent Documents 1 to 3).

[0007] In the technology disclosed in Patent Document 1, the end of the pipe is inserted into a flange fixed to a face plate arranged to face the open faces of both ends of the pipe, and the flange is aligned with the pipe. Next, the flange is pre-welded to the pipe, and then the flange is removed from the face plate, and the flange is finally welded to the pipe. In this technology, the face plate has bolt holes corresponding to a plurality of types of flanges, so that one jig (face plate) can be used to attach flanges to pipes of a plurality of sizes. However, this technology cannot be used to attach flanges to branch pipes. In addition, in this technology, in order to perform the final welding of the flange, the flange must be removed from the face plate together with the pipe, which makes the work process complicated.

[0008] In the technique disclosed in Patent Document 2, the end of a pipe is inserted into a flange fixed to a rotatable claw, and the flange is aligned with respect to the pipe. Next, the flange and the pipe are rotated by rotating the claw while simultaneously welding the inside and outside of the pipe with a welding torch. As a result, this technique realizes the actual welding while positioning the flange on the end of the pipe. However, in this technique, the pipe rotates through the welded points, and the number of welded points increases by the rotation. Therefore, stress is concentrated at the welded points at the beginning of the rotation, and defects such as breakage of the welded points may occur. In addition, this technique cannot accommodate the attachment of a flange to a branch pipe.

[0009] In the technique disclosed in Patent Document 3, the end of a pipe body is inserted into a flange fixed to a rotatable chuck section, and the flange is aligned with respect to the pipe body. A branch pipe protruding in a 90° direction from the outer circumferential surface of the pipe body is connected to the pipe body. Next, a second branch pipe with a flange fixed to its end is fixed to a branch pipe positioner arranged on the side of the pipe body. Next, the chuck section is rotated, so that the branch pipe of the pipe body is oriented horizontally. Next, the position of the branch pipe positioner is adjusted, so that the end of the branch pipe of the pipe body and the end of the second branch pipe are positioned. As a result, the technique realizes alignment of the pipe body and the flange as well as alignment of the branch pipe. However, the technique can accommodate attachment of a flange to one branch pipe, but cannot accommodate attachment of a flange to branch pipes oriented in various directions. In addition, the technique cannot accommodate main welding of the flange and the pipe body while the flange is chucked. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Jpn. Jpn. Published No. 51-44755 [Patent Document 2] JP 2013-18047 A [Patent Document 3] JP 2002-45994 A Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention is directed to aiding in the attachment of flanges to branch pipes that may be oriented in various directions from a main pipe. [Means for solving the problem]

[0012] The flange mounting jig unit according to the present invention is a flange mounting jig unit used for mounting a flange to a tube structure. The tube structure includes a cylindrical tube, a first branch tube connected to an outer peripheral surface of the tube, and a second branch tube connected to the outer peripheral surface in a direction different from that of the first branch tube. The flange includes a first flange attached to each of the first end and the second end of the tube, a second flange attached to the end of the first branch tube, and a third flange attached to the end of the second branch tube. The flange mounting jig unit includes a pair of first jigs that assist the mounting of the first flange to each of the first end and the second end of the tube, a second jig that assists the mounting of the second flange to the end of the first branch tube, and a third jig that assists the mounting of the third flange to the end of the second branch tube. When viewed in the axial direction of the tube, the second jig and the third jig are each disposed on a side of the tube. The first jig is capable of holding the pipe body via the first flange so that the first central axis of the first branch pipe body is parallel to the horizontal direction, and is capable of holding the pipe body via the first flange so that the second central axis of the second branch pipe body is parallel to the horizontal direction. Effect of the Invention

[0013] The present invention can assist in mounting flanges to branch pipes that are oriented in various directions from a main pipe. [Brief description of the drawings]

[0014] [Figure 1] 1 is a perspective view showing an embodiment of a flange mounting jig unit according to the present invention and a flanged pipe structure manufactured using the flange mounting jig unit. FIG. [Diagram 2] FIG. 2 is a view of the flanged pipe structure of FIG. 1 taken along the arrow A. [Diagram 3] 3 is a cross-sectional view of the flanged tube structure of FIG. 2 taken along line BB. [Figure 4] FIG. 2A is a front view of a first flange included in the flanged pipe structure of FIG. 1, and FIG. 2B is a cross-sectional view of the first flange taken along line CC of FIG. [Diagram 5] 2A is a front view of a first jig provided in the flange mounting jig unit of FIG. 1, and FIG. 2B is a right side view of the first jig. [Figure 6] 6 is a schematic diagram illustrating a positional relationship of a first rotation hole with respect to a first mounting hole provided in the first jig in FIG. 5. FIG. [Figure 7] 1. FIG. 4(a): A front view of another first jig provided in the flange mounting jig unit of FIG. 1. FIG. [Figure 8] 2A is a front view of a second jig provided in the flange mounting jig unit of FIG. 1, and FIG. 2B is a right side view of the second jig. [Figure 9] 1. (a) is a front view of a third jig provided in the flange mounting jig unit of FIG. 1, and (b) is a right side view of the third jig. FIG. [Figure 10] 2 is a schematic diagram showing an example of a jig unit included in the flange mounting jig unit of FIG. 1. [Figure 11] 1 is a flowchart showing an embodiment of a method for manufacturing a flanged tube structure according to the present invention. [Figure 12] 12A to 12C are schematic diagrams showing a flange mounting jig unit, and a pipe structure and a flange included in the flanged pipe structure of FIG. 1, at each stage of the manufacturing method of FIG. 11. [Figure 13] FIG. 11 is a perspective view showing another embodiment of a flange mounting jig unit according to the present invention and a flanged pipe structure manufactured using the flange mounting jig unit. [Figure 14] 14(a): a front view of a first jig provided in the flange mounting jig unit of FIG. 13, and FIG. 14(b): a right side view of the first jig. [Figure 15]15 is a schematic diagram for explaining the positional relationship of a first rotation hole and a second rotation hole with respect to a first mounting hole provided in the first jig in FIG. 14. FIG. [Figure 16] 14(a): a front view of another first jig provided in the flange mounting jig unit of FIG. 13, and FIG. 14(b): a right side view of the same first jig. [Figure 17] 5 is a flowchart showing another embodiment of a method for manufacturing a flanged tube structure according to the present invention. [Figure 18] 18A to 18C are schematic diagrams showing a flange mounting jig unit, and a pipe structure and a flange included in the flanged pipe structure of FIG. 13, at each stage of the manufacturing method of FIG. 17. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of a flange installation jig unit (hereinafter referred to as "this unit") according to the present invention and a manufacturing method of a flanged pipe structure (hereinafter referred to as "this method") according to the present invention using this unit will be described with reference to the drawings. In the following description, the flanged pipe structure in the present invention is a horizontal pipe located below a coke oven and supplying gas to the coke oven.

[0016] ●Flanged pipe structure● Configuration of flanged tube structure First, a flanged pipe structure manufactured by this method will be described.

[0017] FIG. 1 is a perspective view showing an embodiment of the unit and a flanged pipe structure. FIG. 2 is a view of the flanged pipe structure taken along the line A in FIG. FIG. 3 is a cross-sectional view of the flanged tube structure taken along line BB in FIG.

[0018] The flanged pipe structure TF constitutes, for example, a part of a piping structure for supplying fuel gas to a coke oven. The flanged pipe structure TF includes a pipe structure T and a flange F. The pipe structure T includes a main pipe T1, a branch pipe T2, and a plurality of (three in this embodiment) branch pipes T3. The flange F includes a pair of first flanges F1, a second flange F2, and a plurality of (three in this embodiment) third flanges F3.

[0019] Each of the main pipe T1, the branch pipe T2, and the branch pipe T3 is cylindrical and made of a metal such as carbon steel. The inner diameter (outer diameter) of the branch pipe T2 is smaller than the inner diameter (outer diameter) of the main pipe T1 and larger than the inner diameter (outer diameter) of the branch pipe T3. The configurations (shape, inner diameter, outer diameter, length) of the branch pipes T3 are the same. In this embodiment, the main pipe T1 is an example of a pipe body in the present invention, the branch pipe T2 is an example of a first branch pipe body in the present invention, and the branch pipe T3 is an example of a second branch pipe body in the present invention.

[0020] The branch pipe T2 protrudes from the outer circumferential surface of the main pipe T1 in the radial direction of the main pipe T1 so that the central axis L2 of the branch pipe T2 is perpendicular to the central axis L1 of the main pipe T1. The central axis L2 is an example of a first central axis in the present invention.

[0021] Each of the three branch pipes T3 protrudes from the outer circumferential surface of the main pipe T1 in a radial direction of the main pipe T1 different from the branch pipe T2 so that the central axis L3 of the branch pipe T3 is perpendicular to the central axis L1 of the main pipe T1. That is, the central axis L3 of the branch pipe T3 is oriented in a direction different from the central axis L2 of the branch pipe T2 when viewed in the axial direction of the main pipe T1. The angle θ between the branch pipe T2 and the branch pipe T3 when viewed in the axial direction of the main pipe T1 is an obtuse angle. The branch pipes T3 are arranged parallel to each other, and the opening surfaces of the ends T3a of the branch pipes T3 are arranged on the same imaginary plane. The central axis L3 is an example of a second central axis in the present invention.

[0022] A pair of first flanges F1 are attached to both ends T1a, T1b of the main pipe T1, respectively, and are connected, for example, to a flange (not shown, same below) of another adjacent pipe structure. The configuration of the first flange F1 will be described later. Both ends T1a, T1b of the main pipe T1 are examples of the first end and the second end of the present invention.

[0023] The second flange F2 is attached to the end T2a of the branch pipe T2 and is connected to a flange (not shown) of a corresponding piping of the equipment. The configuration of the second flange F2 will be described later.

[0024] The three third flanges F3 are attached to the ends T3a of the branch pipes T3, respectively, and are connected to corresponding flanges (not shown) of the piping of the equipment. The configuration of the third flanges F3 will be described later.

[0025] The first flange F1 and the second flange F2 have the same configuration except for the difference in size. The first flange F1 and the third flange F3 have the same configuration except for the difference in size and the number of bolt holes described below. Therefore, in the following explanation, the configuration of the first flange F1 will be used as an example to explain the configurations of the second flange F2 and the third flange F3 as well. In the following explanation of the flange F, the direction of the flange F facing the tube structure T is the rear of the flange F, and the opposite direction is the front of the flange F.

[0026] FIG. 4(a) is a front view of the first flange F1, and (b) is a cross-sectional view of the first flange F1 taken along line CC in (a). For ease of explanation, the reference characters in [ ] in the figure indicate the reference characters given to the elements of the second flange F2 and the third flange F3. In the figure, the end T1a (T1b) of the main pipe T1, the end T2a of the branch pipe T2, and the end T3a of the branch pipe T3 are indicated by two-dot chain lines.

[0027] The first flange F1 is in the shape of a ring plate and is made of a metal such as carbon steel. The first flange F1 has an insertion hole F1h1 and a plurality of (12 in this embodiment) bolt holes F1h2. The insertion hole F1h1 is an example of a first insertion hole in the present invention, and the bolt hole F1h2 is an example of a first bolt hole in the present invention.

[0028] The insertion hole F1h1 is a through hole into which one of the ends T1a, T1b of the main pipe T1 is inserted. The insertion hole F1h1 is disposed in the center of the first flange F1. The inner surface of the front end of the insertion hole F1h1 juts out radially inward of the insertion hole F1h1 to form a reduced diameter section F1h1a. The inner surface of the reduced diameter section F1h1a is a curved surface that has been subjected to R-chamfering and is an arc-shaped surface in cross-sectional view. The rear surface of the reduced diameter section F1h1a stands upright from the inner peripheral surface of the insertion hole F1h1 and forms an abutting surface F1h1b against which the end face of the end T1a (T1b) of the main pipe T1 abuts. In the radial direction of the first flange F1, the length of the abutting surface F1h1b is the same as the thickness of the main pipe T1.

[0029] Here, in a flange (e.g., a plate flange) that does not have a reduced diameter portion F1h1a, after welding between the inner surface of the flange and the end of the tube body, R-chamfering is performed on the excess portion of the weld. This processing is usually performed manually using a grinder or the like. Therefore, it is difficult to maintain the processing accuracy, the processing time is likely to be long, and the processing cost is likely to be high. In addition, defects such as undercuts and damage to the sealing surface of the flange are likely to occur. However, since the first flange F1 has a reduced diameter portion F1h1a, the R-chamfering of the excess portion described above is not necessary. As a result, it is easy to maintain the accuracy of the R surface, and no damage occurs due to processing. In addition, processing using a grinder is limited to smoothing processing, which will be described later, and the processing time and processing cost are reduced.

[0030] The bolt holes F1h2 are through holes through which bolts (not shown) are inserted to fix the first flange F1 to a flange of another tube structure. The bolt holes F1h2 are arranged radially outward from the insertion hole F1h1 at equal angular intervals on an imaginary circle concentric with the insertion hole F1h1.

[0031] As described above, the configuration of the second flange F2 is the same as that of the first flange F1. That is, the second flange F2 includes an insertion hole F2h1, a reduced diameter portion F2h1a, an abutting surface F2h1b, and a plurality of (12 in this embodiment) bolt holes F2h2. The insertion hole F2h1 is an example of a second insertion hole in the present invention.

[0032] As described above, the configuration of the third flange F3 is the same as that of the first flange F1. That is, the third flange F3 includes an insertion hole F3h1, a reduced diameter portion F3h1a, an abutment surface F3h1b, and a plurality of (four in this embodiment) bolt holes F3h2. The insertion hole F3h1 is an example of a third insertion hole in the present invention. The bolt holes F3h2 are arranged radially outward from the insertion hole F3h1 at equal angular intervals on a virtual circle concentric with the insertion hole F3h1.

[0033] ●Flange mounting jig unit (1)● ●Configuration of flange mounting jig unit (1) Next, an embodiment of the unit 1 will be described with reference to Figures 1 to 4. In the following description of the unit 1, the direction facing the tube structure T is the front of the unit 1, and the opposite direction is the rear of the unit 1.

[0034] This unit 1 is an assembly of jigs used by a user of this unit 1 when attaching a flange F to a tube structure T. This unit 1 includes a pair of first jigs 10, 20, a second jig 30, a plurality of (three in this embodiment) third jigs 40, a pedestal 50, a base 60, and a tube holding jig 70.

[0035] FIG. 5(a) is a front view of the first jig 10, and (b) is a right side view of the first jig 10. As shown in FIG. For ease of explanation, in the figure, a first fixing member 13, which will be described later, is indicated by a two-dot chain line.

[0036] The first jig 10 is a jig that assists in mounting the first flange F1 to the end T1a of the main pipe T1. The first jig 10 is L-shaped in a side view and is made of a metal such as carbon steel or stainless steel. The first jig 10 includes a bottom plate 11, a holding plate 12, a first central hole 10h1, a first mounting hole 10h2, a first rotation hole 10h3, and a first fixing member 13.

[0037] The bottom plate 11 supports the retaining plate 12 and fixes the retaining plate 12 to a predetermined position on the base 60. The retaining plate 12 holds the first flange F1 and holds the main pipe T1 via the first flange F1. The bottom plate 11 and the retaining plate 12 are rectangular plates. The retaining plate 12 stands upright from the front end of the bottom plate 11 facing upward. The front surface of the retaining plate 12 is a first abutment surface 12a with which the first flange F1 abuts when the first flange F1 is fixed and held by the retaining plate 12. The first abutment surface 12a is parallel to the vertical direction.

[0038] The first central hole 10h1 is a through hole through which a user can perform predetermined operations (such as alignment and inner surface welding, which will be described later) when the first flange F1 is attached to the main pipe T1. The first central hole 10h1 is disposed in the center of the retaining plate 12. The inner diameter of the first central hole 10h1 is approximately the same as the inner diameter of the insertion hole F1h1 of the first flange F1, and is larger than the outer diameter of the main pipe T1.

[0039] The first mounting holes 10h2 are holes through which the first fixing members 13 are passed (threaded) to fix the first flange F1 to the first contact surface 12a when the first flange F1 is attached to the end T1a of the main pipe T1. In this embodiment, the first mounting holes 10h2 include four first mounting holes 10h21 to 10h24. The first mounting holes 10h21 and 10h22 are through holes corresponding to the first fixing members 131 and 132 described later, and the first mounting holes 10h23 and 10h24 are female threaded holes corresponding to the first fixing members 133 and 134 described later. In the following description, each of the first mounting holes 10h21 to 10h24 will be referred to as the first mounting hole 10h2 unless otherwise specified.

[0040] In a front view, the first mounting holes 10h2 are arranged at equal angular intervals (90° intervals in this embodiment) on a virtual circle C1 concentric with the first central hole 10h1. The first mounting hole 10h21 is arranged above the first central hole 10h1, the first mounting hole 10h22 is arranged below the first central hole 10h1, the first mounting hole 10h23 is arranged to the left of the first central hole 10h1, and the first mounting hole 10h24 is arranged to the right of the first central hole 10h1. The two first mounting holes 10h21 and 10h22 are arranged in point symmetry with respect to the center point O1 of the first central hole 10h1, and the two first mounting holes 10h23 and 10h24 are arranged in point symmetry with respect to the center point O1. The two first mounting holes 10h21, 10h22 and the two first mounting holes 10h23, 10h24 each constitute a pair of first mounting holes in the present invention.

[0041] The first rotation hole 10h3 is a hole through which the first fixing member 13 is passed (screwed) to fix the first flange F1 to the first abutment surface 12a when the third flange F3 is attached to the end T3a of the branch pipe T3. In this embodiment, the first rotation hole 10h3 includes four first rotation holes 10h31 to 10h34. The first rotation holes 10h31 and 10h32 are through holes corresponding to the first fixing members 131 and 132 described later, and the first rotation holes 10h33 and 10h34 are female thread holes corresponding to the first fixing members 133 and 134 described later. In the following description, each of the first rotation holes 10h31 to 10h34 will be referred to as the first rotation hole 10h3 unless otherwise specified.

[0042] The first rotation holes 10h3 are arranged at equal angular intervals (90° intervals in this embodiment) on a virtual circle C1 in a front view. The first rotation hole 10h31 is arranged at a position rotated counterclockwise by a first angle "θ1" from the corresponding first mounting hole 10h21 around a center point O1 in a front view. Similarly, the first rotation holes 10h32-10h34 are arranged at positions rotated counterclockwise by a first angle "θ1" from the corresponding first mounting holes 10h22-10h24. That is, the two first rotation holes 10h31 and 10h32 are arranged at positions symmetrical with respect to the center point O1 of the first central hole 10h1, and the two first rotation holes 10h33 and 10h34 are arranged at positions symmetrical with respect to the center point O1. The first angle "θ1" will be described later. The two first rotation holes 10h31, 10h32 and the two first rotation holes 10h33, 10h34 each constitute a pair of first rotation holes in the present invention.

[0043] The first fixing members 13 are bolts that fix the first flange F1 to the first contact surface 12a. The first fixing members 13 are made of metal such as high-strength steel. In this embodiment, the first fixing members 13 include four first fixing members 131 to 134. The first fixing members 131 and 132 are, for example, hexagonal reamer bolts. The first fixing members 133 and 134 are, for example, hexagonal bolts having fully threaded portions.

[0044] 6 is a schematic diagram for explaining the positional relationship of the first rotation hole 10h3 with respect to the first mounting hole 10h2. The figure shows the first jig 10 as viewed from the back (as viewed in the axial direction of the main pipe T1). For convenience of explanation, the figure also shows the central axes L2 and L3.

[0045] The first angle "θ1" is determined by the angle (90° or less) between the central axis L3 and the horizontal direction in the axial view of the main pipe T1 when the end T1a of the main pipe T1 is inserted into the insertion hole F1h1 of the first flange F1 fixed to the first abutment surface 12a by the first fixing member 13 passed through the first mounting hole 10h2 and the bolt hole F1h2, and the central axis L2 of the branch pipe T2 is oriented horizontally (parallel to the horizontal direction). That is, for example, the first angle "θ1" is the same as the angle between the central axis L3 and the horizontal direction.

[0046] The position of the first rotation hole 10h3 relative to the first mounting hole 10h2 is a position rotated by a first angle "θ1" from the position of the first mounting hole 10h2 about the center point O1 so that the central axis L3 is horizontal in rear view.

[0047] Here, the first angle "θ1" is different from the angle between the bolt holes F1h2 of the first flange F1 (any of 30°, 45°, and 90°). That is, when the first flange F1 is fixed to the first contact surface 12a by the first fixing member 13 passed through the first mounting hole 10h2 and the bolt hole F1h2, the position of the first rotation hole 10h3 differs from the position of each of the bolt holes F1h2 of the first flange F1 in the circumferential direction of the first flange F1 (the circumferential direction of the imaginary circle C1).

[0048] 7(a) is a front view of the first jig 20, and (b) is a right side view of the first jig 20. FIG.

[0049] The first jig 20 is a jig that assists in mounting the first flange F1 to the end T1b of the main pipe T1. The first jig 20 includes a bottom plate 21, a holding plate 22, a first central hole 20h1, four first mounting holes 20h21-20h24, four first rotation holes 20h31-20h34, and four first fixing members 231-234. In the following description, unless otherwise specified, the four first mounting holes 20h21-20h24 will be referred to as first mounting holes 20h2, and the four first rotation holes 20h31-20h34 will be referred to as first rotation holes 20h3.

[0050] The configuration of the first jig 20 is the same as that of the first jig 10, except that the left and right directions in a front view are in a mirror image relationship with respect to the first jig 10. Therefore, details of the configuration of the first jig 20 will be omitted.

[0051] 8(a) is a front view of the second jig 30, and (b) is a right side view of the second jig 30. FIG.

[0052] The second jig 30 is a jig that assists in mounting the second flange F2 to the end T2a of the branch pipe T2. The second jig 30 is L-shaped in a side view and is made of a metal such as carbon steel or stainless steel. The second jig 30 includes a bottom plate 31, a holding plate 32, a second central hole 30h1, a second mounting hole 30h2, and a second fixing member 33. The configuration of the second jig 30 is the same as that of the first jig 10, except for the size and the fact that the second jig 30 does not include a first rotation hole and a second rotation hole. Therefore, a description of the configuration of the second jig 30 will be omitted.

[0053] The bottom plate 31 and the holding plate 32 are rectangular plates. The holding plate 32 stands upward from the front end of the bottom plate 31. The front surface of the holding plate 32 is a second abutment surface 32a with which the second flange F2 abuts when the holding plate 32 holds the second flange F2. The second abutment surface 32a is parallel to the vertical direction.

[0054] The second central hole 30h1 is disposed in the center of the retaining plate 32. The inner diameter of the second central hole 30h1 is approximately the same as the inner diameter of the insertion hole F2h1 of the second flange F2, and is larger than the outer diameter of the branch pipe T2.

[0055] The second mounting hole 30h2 includes four second mounting holes 30h21 to 30h24. The second mounting holes 30h21 and 30h22 are through holes corresponding to second fixing members 331 and 332, which will be described later, and the second mounting holes 30h23 and 30h24 are female threaded holes corresponding to second fixing members 333 and 334, which will be described later. In the following description, each of the second mounting holes 30h21 to 30h24 will be referred to as a second mounting hole 30h2 unless otherwise specified.

[0056] The second fixing member 33 includes four second fixing members 331 to 334. The second fixing members 331 and 332 are, for example, hexagonal reamer bolts. The second fixing members 333 and 334 are, for example, hexagonal bolts having a fully threaded portion.

[0057] 9(a) is a front view of the third jig 40, and (b) is a right side view of the third jig 40. FIG.

[0058] The third jig 40 is a jig that assists in mounting the third flange F3 to the end T3a of the branch pipe T3. The third jig 40 is L-shaped in a side view and is made of a metal such as carbon steel or stainless steel. The third jig 40 includes a bottom plate 41, a holding plate 42, a third central hole 40h1, a third mounting hole 40h2, and a third fixing member 43. The configuration of the third jig 40 is the same as that of the second jig 30, except for the size. Therefore, a description of the configuration of the third jig 40 will be partially omitted.

[0059] The bottom plate 41 and the holding plate 42 are rectangular plates. The holding plate 42 stands upward from the front end of the bottom plate 41. The front surface of the holding plate 42 is a third abutment surface 42a with which the third flange F3 abuts when the holding plate 42 holds the third flange F3. The third abutment surface 42a is parallel to the vertical direction.

[0060] The third central hole 40h1 is disposed in the center of the retaining plate 42. The inner diameter of the third central hole 40h1 is approximately the same as the inner diameter of the insertion hole F3h1 of the third flange F3, and is larger than the outer diameter of the branch pipe T3.

[0061] The third mounting hole 40h2 includes four third mounting holes 40h21 to 40h24. The third mounting holes 40h21 and 40h22 are through holes corresponding to the third fixing members 431 and 432 described later, and the third mounting holes 40h23 and 40h24 are female threaded holes corresponding to the third fixing members 433 and 434 described later. In the following description, the third mounting holes 40h21 to 40h24 will be referred to as the third mounting hole 40h2 unless otherwise specified.

[0062] The third fixing member 43 includes four third fixing members 431 to 434. The third fixing members 431 and 432 are, for example, hexagonal reamer bolts. The third fixing members 433 and 434 are, for example, hexagonal bolts having a fully threaded portion.

[0063] Return to Figure 1. The pedestal 50 fixes the relative positions of the multiple third jigs 40, and together with the multiple (three in this embodiment) third jigs 40, constitutes an integrated jig unit U. The pedestal 50 has a rectangular plate shape and is made of a metal such as carbon steel or stainless steel.

[0064] FIG. 10 is a schematic diagram showing an example of the jig unit U. As shown in FIG. 10, in this embodiment, the unit 1 includes a plurality of jig units U (U1 to U4 in FIG. 10) in which the position and / or number of the third jigs 40 differ. The position and number of the third jigs 40 in each jig unit U correspond to the configuration (length, position, number) of the branch pipe T3. The jig units U are interchangeable with each other. In this embodiment, the third contact surfaces 42a of the third jigs 40 fixed to the pedestals 50 on the jig units U1 to U3 are arranged on the same imaginary plane.

[0065] In addition, the third contact surfaces of the third jigs on the jig unit of the present invention do not have to be arranged on the same imaginary plane. That is, for example, when the lengths of the branch pipes are different, the contact surfaces of the third jigs may be arranged shifted in the front-rear direction according to the lengths of the corresponding branch pipes, as in the jig unit marked with the symbol "U4" in Fig. 10.

[0066] Return to Figure 1. The base 60 fixes the unit 1 (first jigs 10, 20, second jig 30, jig unit U (third jig 40 and base 50)) to a predetermined position relative to the pipe structure T. Specifically, the first jig 10 is disposed on one axial side of the main pipe T1, and the first jig 20 is disposed on the other axial side of the main pipe T1. Also, when viewed in the axial direction of the main pipe T1, the second jig 30 is disposed on one side of the main pipe T1, and the third jig 40 is disposed on the other side of the main pipe T1. The base 60 has a rectangular plate shape and is made of a metal such as carbon steel. The base 60 has, for example, a plurality of bolt holes (not shown) into which bolts (not shown) are screwed to fix the unit 1 in a predetermined position.

[0067] The pipe holding jig 70 holds the pipe structure T at a predetermined height. The pipe holding jig 70 includes a frame 71 and a pair of rollers 72 (one of which is not shown; the same applies below). The frame 71 rotatably holds the rollers 72 so that the rollers 72 are positioned at a predetermined height. When the main pipe T1 (described later) is rotated, the rollers 72 rotate together with the main pipe T1, thereby assisting the rotation of the main pipe T1.

[0068] ●Manufacturing method of flanged tube structure (1)● Next, an embodiment of the present method will be described with reference to Figures 1 to 9. In the following, the present method will be described taking as an example a case in which a flange F is attached to a tube structure T using the present unit 1.

[0069] FIG. 11 is a flow chart illustrating an embodiment of the method. Fig. 12 is a schematic diagram showing the unit 1, the pipe structure T, and the flange F at each stage of the method. For ease of explanation, Fig. 12 shows the first mounting holes 10h21-24 and the first rotation holes 10h31-10h34 with reduced diameters and indicated by "●". Fig. 12 also shows the first fixing members 131-134 with two-dot chain lines. Fig. 12 also shows the first jig 10 as viewed from the back (as viewed in the axial direction of the main pipe T1).

[0070] First, the first jigs 10, 20, the second jig 30, the jig unit U and the pipe holding jig 70 are placed on the base 60 (installation of the main unit 1), and the pipe structure T is held at a predetermined height from the base 60 by the pipe holding jig 70 (S1). At this time, the first jig 10 is disposed and fixed on one axial side of the main pipe T1, the first jig 20 is disposed on the other axial side of the main pipe T1, the second jig 30 is disposed on one radial side of the main pipe T1, and the third jig 40 is disposed on the other radial side of the main pipe T1.

[0071] Next, the flanges F are fixed to the unit 1 (S2). That is, the first flange F1 is fixed to the first jigs 10 and 20, the second flange F2 is fixed to the second jig 30, and the third flange F3 is fixed to the third jig 40.

[0072] Here, the first flange F1 is fixed to the first abutment surface 12a by the first fixing member 13. Specifically, in a state where the front surface of the first flange F1 abuts against the first abutment surface 12a of the first jig 10, the first fixing members 131, 132 are inserted into the bolt hole F1h2 and the first mounting holes 10h21, 10h22. As a result, the first flange F1 is positioned with respect to the first abutment surface 12a. Also, the first fixing members 133, 134 are inserted into the bolt holes F1h2 and screwed into the first mounting holes 10h23, 10h24. As a result, the first flange F1 is fixed to the first abutment surface 12a of the first jig 10. Similarly, the first flange F1 is fixed to the first jig 20. At this time, the first central hole 10h1 communicates with the insertion hole F1h1 of the first flange F1. When viewed in the axial direction of the main pipe T1, the center point O1 of the first central hole 10h1 overlaps with the center point of the insertion hole F1h1.

[0073] In the following description, the bolt hole F1h2 through which the first fixing members 131, 132 (first fixing members 231, 232) are inserted may be referred to as the first reference hole, and the bolt hole F1h2 through which the first fixing members 133, 134 (first fixing members 233, 234) are inserted may be referred to as the second reference hole.

[0074] The second flange F2 is fixed to the second abutment surface 32a by the second fixing member 33. At this time, the second central hole 30h1 communicates with the insertion hole F2h1 of the second flange F2. When viewed in the axial direction of the branch pipe T2, the center point O3 of the second central hole 30h1 overlaps with the center point of the insertion hole F2h1. The method of fixing the second flange F2 to the second jig 30 is similar to the method of fixing the first flange F1 to the first jig 10, so details will be omitted.

[0075] Furthermore, the third flange F3 is fixed to each third abutment surface 42a of the jig unit U by the third fixing member 43. At this time, the third central hole 40h1 communicates with the insertion hole F3h1 of the third flange F3. The center point O4 of the third central hole 40h1 overlaps with the center point of the insertion hole F3h1. Here, the jig unit U is selected in advance by the user. The method of fixing the third flange F3 to the third jig 40 is similar to the method of fixing the first flange F1 to the first jig 10, so details will be omitted.

[0076] Next, the end portion T1a of the main pipe T1 is inserted into the insertion hole F1h1 of the first flange F1 fixed to the first jig 10 (S3).

[0077] Next, the end portion T1b of the main pipe T1 is inserted into the insertion hole F1h1 of the first flange F1 fixed to the first jig 20 (S4). At this time, for example, the user moves the first jig 20 forward (towards the main pipe T1), whereby the end portion T1b is inserted into the insertion hole F1h1.

[0078] Next, the first jig 20 and the pipe structure T are pushed toward the first jig 10 in the axial direction of the main pipe T1 until the end faces of the ends T1a and T1b of the main pipe T1 relative to the insertion hole F1h1 abut against the corresponding abutment surfaces F1h1b (S5). As a result, the end T1a is aligned with respect to the insertion hole F1h1. As described above, the first central holes 10h1 and 20h1 having approximately the same diameter as the inner diameter of the insertion hole F1h1 of the first flange F1 are arranged in the holding plates 12 and 22. Therefore, the user can easily visually confirm the positions of the ends T1a and T1b of the main pipe T1 in the insertion hole F1h1 through the first central holes 10h1 and 20h1. That is, it becomes easy to align the ends T1a and T1b with respect to the first flange F1 (insertion hole F1h1).

[0079] Next, the main pipe T1 is rotated circumferentially around the first flange F1 so that the central axis L2 of the branch pipe T2 is aligned horizontally (parallel to the horizontal), thereby aligning the position of the main pipe T1 relative to the first jigs 10, 20 (S6: first alignment process).

[0080] Next, the position of the second jig 30 to which the second flange F2 is fixed is adjusted with respect to the pipe structure T (S7). Specifically, the second contact surface 32a is arranged parallel to the opening surface of the end portion T2a of the branch pipe T2, and the central axis L2 is directed to the center point O3 of the second central hole 30h1.

[0081] Next, the end portion T2a of the branch pipe T2 is inserted into the insertion hole F2h1 of the second flange F2 (S8). At this time, for example, the user moves the second jig 30 toward the branch pipe T2 side, whereby the end portion T2a is inserted into the insertion hole F2h1.

[0082] Next, the second jig 30 is pushed into the branch pipe T2 in the axial direction of the branch pipe T2 until the end face of the end T2a of the branch pipe T2 relative to the insertion hole F2h1 abuts against the corresponding abutment surface F2h1b (S9). As a result, the position of the end T2a is aligned with respect to the insertion hole F2h1. At this time, the user can easily visually confirm the position of the end face of the end T2a of the branch pipe T2 in the insertion hole F2h1 through the second central hole 30h1. That is, it becomes easy to align the end T2a with respect to the second flange F2.

[0083] At this time, the first flange F1 is not attached (welded) to the ends T1a, T1b of the main pipe T1. Therefore, the main pipe T1 is subjected to a stress due to the weight of the branch pipe T2 (or branch pipe T3) that rotates in a direction in which the branch pipe T2 (branch pipe T3) descends. However, the end T2a of the branch pipe T2 is inserted into the insertion hole F2h1 of the second flange F2, so that the end T2a is held by the second jig 30 via the second flange F2 (holding step). That is, in this method, the holding step is performed after the first alignment step. Therefore, even before the first flange F1 is attached, the main pipe T1 is held by the first jigs 10, 20 and the second jig 30 via the first flange F1 and the second flange F2 so that the central axis L2 is parallel to the horizontal direction without rotating.

[0084] Next, each of the first flanges F1 is welded to the ends T1a, T1b of the main pipe T1 (S10). As a result, each of the first flanges F1 is attached to the ends T1a, T1b of the main pipe T1 (first flange attachment process). At this time, the outer peripheral surface of the main pipe T1 is welded to the rear surface of the first flange F1 (outer surface welding), and each end surface of the ends T1a, T1b of the main pipe T1 is welded to the corresponding abutment surface F1h1b (inner surface welding). At this time, a user can easily perform inner surface welding with the first flange F1 fixed to the first jig 10, 20 by inserting a welding torch into the insertion hole F1h1 of the first flange F1 through the first central hole 10h1, 20h1.

[0085] Here, the end faces of the ends T1a and T1b of the main pipe T1 are grooved, and the inner surface is welded to fill the gap between the end face and the abutting surface F1h1b, including the grooved portion. As a result, no air remains in the inner surface welded portion, and the expansion of the remaining air due to the heat of the gas (expansion of the inner surface welded portion) does not occur. Therefore, even if a coating is applied to the inner surface of the flanged pipe structure TF, problems such as peeling of the coating starting from the inner surface welded portion do not occur.

[0086] Next, the excess portion of the inner welded portion is smoothed by a grinder or the like (S11). At this time, the user can easily perform the smoothing process while the first flange F1 is fixed to the first jig 10, 20 by inserting a grinder into the insertion hole F1h1 of the first flange F1 through the first central hole 10h1, 20h1. In addition, since this smoothing process only smooths the inner welded portion to match the inner diameter of the main pipe T1, the process can be easily performed in a short time. By performing the smoothing process in this manner, even if a coating is applied to the inner surface of the flanged pipe structure TF, the inner welded portion does not have any unevenness that may cause the coating to break, and defects such as peeling of the coating starting from the inner welded portion do not occur.

[0087] Here, in a state (first mounting state) in which the first flange F1 attached to the main pipe T1 is fixed to the first jig 10, 20, the central axis L2 of the branch pipe T2 is parallel to the horizontal direction, and the central axis L3 of the branch pipe T3 is inclined at a first angle "θ1" from the horizontal direction. Meanwhile, the first rotation holes 10h3, 20h3 are disposed at positions rotated at the first angle "θ1" from the positions of the first mounting holes 10h2, 20h2 (first reference hole, second reference hole). In this way, the first jig 10, 20 can fix the first flanges F1 attached to the ends T1a, T1b, respectively, so that the central axis L2 of the branch pipe T2 is parallel to the horizontal direction. In other words, the first jig 10, 20 can hold the main pipe T1 via the first flange F1 so that the central axis L2 is parallel to the horizontal direction.

[0088] In the axial view of the main pipe T1 in the first mounting state, the positions of the first mounting holes 10h2 coincide with the positions of the bolt holes F1h2, which are the first and second reference holes. The central axis L2 is parallel to the horizontal direction. In the axial view, the first rotation holes 10h3 and 20h3 are disposed at positions rotated by a first angle "θ1" around the center points O1 and O2 of the first central holes 10h1 and 20h1 from the respective positions of the bolt holes F1h2, which are the first reference hole and the bolt holes F1h2, which are the second reference hole, among the multiple bolt holes F1h2.

[0089] Next, the second flange F2 is welded to the end T2a of the branch pipe T2 in the same manner as in the first attachment step (S12). As a result, the second flange F2 is attached to the end T2a of the branch pipe T2 (second flange attachment step). At this time, with the second flange F2 fixed to the second jig 30, the user can easily perform inner surface welding through the second central hole 30h1.

[0090] Next, similarly to the first flange F1, the excess portion of the inner surface weld is smoothed with a grinder or the like (S13). At this time, with the second flange F2 fixed to the second jig 30, the user can easily perform the smoothing process through the second central hole 30h1.

[0091] Here, when the second flange F2 attached to the branch pipe T2 is fixed to the second jig 30 (second mounting state), the central axis L2 of the branch pipe T2 is parallel to the horizontal direction, and the central axis L3 of the branch pipe T3 is inclined at a predetermined angle "θ1" from the horizontal direction.

[0092] Next, the second flange F2 attached to the branch pipe T2 and the first flange F1 attached to the main pipe T1 are removed from the first jig 10, 20 and the second jig 30 (S14). Specifically, the second flange F2 is removed from the second jig 30, and then the first flange F1 is removed from the first jig 10, 20. As a result, the pipe structure T to which the first flange F1 is attached becomes movable.

[0093] Next, the main pipe T1 is rotated in the circumferential direction of the first flange F1 so that the central axis L3 of the branch pipe T3 is aligned along the horizontal direction (parallel to the horizontal direction), thereby aligning the position of the main pipe T1 with respect to the first jig 10, 20 (S15: second alignment step). Specifically, the main pipe T1 is rotated by a predetermined angle ("θ1") in the circumferential direction of the main pipe T1 around the central axis L1 of the main pipe T1 so that the first reference hole (bolt hole F1h2) overlaps with the first rotation holes 10h31, 10h32, 20h31, 20h32 of the first jig 10, 20 when viewed in the axial direction of the main pipe T1. At this time, the roller 72 of the pipe holding jig 70 rotates together with the main pipe T1, allowing the main pipe T1 to rotate smoothly. After the main pipe T1 is rotated, the first flange F1 is fixed to the first jig 10, 20 (rotation and fixation step). That is, for example, in a state where the front surface of the first flange F1 is in contact with the first abutment surface 12a of the first jig 10, the first fixing members 131, 132 are inserted into the first reference hole and the first rotation holes 10h31, 10h32. As a result, the first flange F1 is positioned at a position where the first reference hole is rotated by the first angle "θ1" from the first mounting holes 10h21, 10h22 in the circumferential direction of the first flange F1 with respect to the first abutment surface 12a. Also, the first fixing members 133, 134 are inserted into the second reference hole and screwed into the first rotation holes 10h33, 10h34. As a result, the first flange F1 is fixed to the first abutment surface 12a of the first jig 10. Similarly, the first flange F1 is fixed to the first abutment surface 22a of the first jig 20. At this time, the central axis L3 of the branch pipe T3 is parallel to the horizontal direction. In this way, the first jigs 10 and 20 can fix the first flanges F1 attached to the ends T1a and T1b of the branch pipe T3 so that the central axis L3 of the branch pipe T3 is parallel to the horizontal direction. In other words, the first jigs 10 and 20 can hold the main pipe T1 via the first flanges F1 so that the central axis L3 is parallel to the horizontal direction.

[0094] Next, the position of the jig unit U (the third jig 40, the base 50) to which the third flange F3 is fixed is adjusted with respect to the pipe structure T (S16). Specifically, the third contact surface 42a is arranged parallel to the opening surface of the end portion T3a of the branch pipe T3, and each central axis L3 is directed toward the center point O4 of the corresponding third central hole 40h1.

[0095] Next, the ends T3a of the branch pipes T3 are inserted into the corresponding insertion holes F3h1 of the third flange F3 (S17). At this time, for example, the user moves the jig unit U (the third jig 40, the base 50) toward the branch pipe T3, whereby the ends T3a are inserted into the insertion holes F3h1.

[0096] Next, the jig unit U (third jig 40, base 50) is pushed toward the branch pipe T3 in the axial direction of the branch pipe T3 until the end face of the end T3a of the branch pipe T3 relative to the insertion hole F3h1 abuts against the abutment surface F3h1b (S18). As a result, the position of the end T3a is aligned with respect to the insertion hole F3h1. At this time, the user can easily visually confirm the position of the end T3a of the branch pipe T3 within the insertion hole F3h1 through the third central hole 40h1. That is, it becomes easier to align the end T3a with respect to the third flange F3.

[0097] Here, as described above, the three third abutment surfaces 42a of the jig unit U are disposed on the same imaginary plane. Therefore, the user can abut (position) the end faces of the ends T3a of the corresponding branch pipes T3 against the abutment surfaces F3h1b of the three third flanges F3 all at once. Even if the lengths of the branch pipes T3 are different to the extent that the attachment of the third flanges F3 is not hindered, the user can attach the third flanges F3 to the ends T3a of the branch pipes T3 while aligning them on the same imaginary plane.

[0098] Next, the third flange F3 is welded to the end T3a of the branch pipe T3 (S19) in the same manner as in the first attachment step. As a result, the third flange F3 is attached to the end T3a of the branch pipe T3 (third flange attachment step). At this time, with the third flange F3 fixed to the third jig 40, the user can easily perform inner surface welding through the third central hole 40h1.

[0099] Next, similarly to the first flange F1, the excess portion of the inner surface weld is smoothed with a grinder or the like (S20). At this time, with the third flange F3 fixed to the third jig 40, the user can easily perform the smoothing process through the third central hole 40h1.

[0100] Next, the third flange F3 attached to the branch pipe T3 and the first flange F1 attached to the main pipe T1 are removed from the first jigs 10, 20 and the third jig 40 (S21). As a result, the pipe structure T with all the flanges F attached (i.e., the flanged pipe structure TF) is removed from the unit 1. Thereafter, the flanged pipe structure TF is coated on the inner surface as necessary.

[0101] Thus, the method includes a first positioning step, a first flange mounting step, a second flange mounting step, a second positioning step, and a third flange mounting step. In this configuration, the user can easily mount the first flange F1 at an appropriate position relative to the ends T1a and T1b of the main pipe T1. In addition, the user can easily position and mount the second flange F2 at an appropriate position relative to the end T2a of the branch pipe T2 by rotating the pipe structure T so that the central axis L2 is parallel to the horizontal direction and fixing the pipe structure T to the first jig 10 or 20. Similarly, the user can easily position and mount the third flange F3 at an appropriate position relative to the end T3a of the branch pipe T3 by rotating the pipe structure T so that the central axis L3 is parallel to the horizontal direction and fixing the pipe structure T to the first jig 10 or 20. In other words, the method can assist in mounting the flanges F to the branch pipe T2 and the branch pipe T3 that are connected to the outer circumferential surface of the main pipe T1 at different angles.

[0102] Moreover, the first flange attachment step and the second flange attachment step are each performed after the first positioning step. In this configuration, after the first flange F1 is positioned at an appropriate position relative to the ends T1a, T1b of the main pipe T1 and the second flange F2 is positioned at an appropriate position relative to the end T2a of the branch pipe T2, the user can attach the first flange F1 and the second flange F2 to the corresponding ends T1a, T1b, T2a successively (or simultaneously).

[0103] Furthermore, the second alignment step is performed after the first flange attachment step and the second flange attachment step, and includes a rotation and fixing step. In this configuration, the user can hold the pipe structure T in the first jig 10, 20 with the central axis L3 parallel to the horizontal direction simply by fixing the first flange F1 rotated together with the pipe structure T to the first jig 10, 20. As a result, the third flange F3 can be easily attached to the branch pipe T3.

[0104] Furthermore, in the present unit 1, the first jigs 10 and 20 have a function of holding the pipe structure T via the first flange F1 and adjusting the position of the first flange F1 relative to the main pipe T1 when the first flange F1 is attached to the main pipe T1, a function of holding the pipe structure T when the second flange F2 is attached to the branch pipe T2, and a function of holding the pipe structure T when the third flange F3 is attached to the branch pipe T3. In other words, in the present unit 1, when the first to third flanges F1 to F3 are attached to the pipe structure T, the pipe structure T can be held only by the first jigs 10 and 20. Furthermore, in the present unit 1, an operator can successively perform the first alignment step, the first flange attachment step, the second flange attachment step, the second alignment step, the rotation and fixation step, and the third flange attachment step without moving or replacing the first jigs 10 and 20.

[0105] The second flange and the third flange in the present invention may be fixed to the second jig 30 and the third jig 40 when the positions of the second jig 30 and the third jig 40 are adjusted, respectively.

[0106] In order to improve the rotation efficiency of the flange attachment using this unit, temporary welding of only the outer surface may be performed in steps (S10, S12, S19), and inner surface welding may be performed after step (S21). In this case, steps (S11, S13, S20) may be performed consecutively or simultaneously after the inner surface welding.

[0107] Furthermore, in this method, the process (S12) may be performed consecutively or simultaneously with the process (S10), in which case the process (S13) may then be performed consecutively or simultaneously with the process (S11).

[0108] Summary (1) According to the embodiment described above, the unit 1 includes the first jigs 10 and 20, the second jigs 30, and the third jigs 40. When viewed in the axial direction of the main pipe T1, the second jigs 30 and the third jigs 40 are disposed on the sides of the main pipe T1. The first jigs 10 and 20 can hold the main pipe T1 via the first flange F1 so that the central axis L2 of the branch pipe T2 is parallel to the horizontal direction, and can hold the main pipe T1 via the first flange F1 so that the central axis L3 of the branch pipe T3 is parallel to the horizontal direction. According to this configuration, the user can attach the second flange F2 to the end T2a of the branch pipe T2 using the second jig 30 by orienting the central axis L2 parallel to the horizontal direction toward the second jig 30 disposed on one side of the main pipe T1. Meanwhile, the user can orient the central axis L3 parallel to the horizontal direction toward the third jig 40 arranged on the other side of the main pipe T1, and use the third jig 40 to attach the third flange F3 to the end T3a of the branch pipe T3. That is, with a simple configuration in which the unit 1 holds the main pipe T1 via the first flange F1 so that the central axes L2, L3 are each parallel to the horizontal direction, it can assist in the attachment of the flanges F to the branch pipe T2 and branch pipe T3, which are connected to the outer circumferential surface of the main pipe T1 at different angles.

[0109] Furthermore, according to the embodiment described above, each of the first jigs 10, 20 includes a first abutment surface 12a, 22a parallel to the vertical direction, a first central hole 10h1, 20h1, a pair of first mounting holes 10h2, 20h2 and a pair of first rotation holes 10h3, 20h3 arranged on the same imaginary circle as the first central holes 10h1, 20h1, and a first fixing member 13, 23. When the first flange F1 is attached to ends T1a, T1b of the main pipe T1, and when viewed in the axial direction of the main pipe T1, the positions of each of the first mounting holes 10h2 coincide with the positions of the bolt holes F1h2 which are the first reference hole and the second reference hole, and the central axis L2 is parallel to the horizontal direction, when viewed in the same axial direction, the first rotation holes 10h3, 20h3 are positioned at a position rotated by the first angle "θ1" from one of the positions of the multiple bolt holes F1h2 (in this embodiment, the respective positions of the bolt hole F1h2 which is the first reference hole and the bolt hole F1h2 which is the second reference hole). According to this configuration, the user can easily make the central axis L3 parallel to the horizontal direction by passing the first fixing members 13, 23 through the bolt holes (first reference holes) F1h2 and the first rotation holes 10h3, 20h3 through which the first fixing members 13, 23 were passed when the first flange F1 was attached to the ends T1a, T1b of the main pipe T1. In other words, with the simple configuration in which the first jigs 10, 20 have the first rotation holes 10h3, 20h3 corresponding to the first angle "θ1", the unit 1 can make the central axes L2, L3 parallel to the horizontal direction and assist in the attachment of the flange F to the branch pipe T2 and the branch pipe T3 that are connected to the outer circumferential surface of the main pipe T1 at different angles.

[0110] Further, according to the embodiment described above, the first rotation holes 10h3, 20h3 are disposed at positions rotated by the first angle "θ1" from the positions of the first mounting holes 10h2, 20h2 about the center point O1 of the first central holes 10h1, 20h1. According to this configuration, the user can easily make the central axis L3 parallel to the horizontal direction by passing the first fixing members 13, 23 through the bolt holes (first reference holes) F1h2 and the first rotation holes 10h3, 20h3 through which the first fixing members 13, 23 were passed when the first flange F1 was attached to the ends T1a, T1b of the main pipe T1. That is, the user can perform the rotation and fixation process using only the first and second reference holes among the multiple bolt holes F1h2. Therefore, the user can perform the rotation and fixation process quickly and without errors.

[0111] Furthermore, according to the embodiment described above, when the first flange F1 is fixed to the first abutment surfaces 12a, 22a by the first fixing members 13, 23 passed through the first mounting holes 10h2, 20h2 and the bolt holes F1h2, the positions of the first rotation holes 10h3, 20h3 are different from the positions of the bolt holes F1h2 of the first flange F1 in the circumferential direction of the first flange F1 (the circumferential direction of the imaginary circle C1). According to this configuration, the first rotation holes 10h3, 20h3 can be disposed at any angle with respect to the first mounting holes 10h2, 20h2 that is different from the angle between the bolt holes F1h2 of the first flange F1. As a result, the unit 1 can fix the tube structure T so that the central axes L2, L3, which are oriented at an angle different from the angle between the bolt holes F1h2 with respect to the horizontal direction, are parallel to the horizontal direction.

[0112] Furthermore, according to the embodiment described above, when the central axis L2 is parallel to the horizontal direction, the second abutment surface 32a is disposed parallel to the opening surface of the end T2a of the branch pipe T2, and the central axis L2 is directed to the center point O3 of the second central hole 30h1. With this configuration, the user can easily align the second flange F2 with the end T2a by pushing the second jig 30 toward the end T2a.

[0113] Furthermore, according to the embodiment described above, when the first flange F1 attached to the main pipe T1 is fixed to the first jig 10, 20 so that the central axis L3 is parallel to the horizontal direction, the third contact surface 42a is arranged parallel to the opening surface of the end T3a of the branch pipe T3, and the central axis L3 is directed to the center point O4 of the third central hole 40h1. With this configuration, the user can easily align the third flange F3 with the end T3a by pushing the third jig 40 toward the end T3a.

[0114] Furthermore, according to the embodiment described above, the third abutment surfaces 42a of the multiple (three) third jigs 40 are arranged on the same imaginary plane. With this configuration, the user can align each of the multiple third flanges F3 with the end surface of the end T3a of the corresponding branch pipe T3 all at once. Even if the lengths of the branch pipes T3 differ to the extent that the attachment of the third flanges F3 is not hindered, the user can attach each third flange F3 to the end T3a of the branch pipe T3 with the third flanges F3 aligned on the same imaginary plane.

[0115] Furthermore, according to the embodiment described above, the multiple third jigs 40 and the base 50 configure an integrated jig unit U. With this configuration, the user can move all of the third jigs 40 while keeping the positional relationships of the multiple third jigs 40 fixed, simply by moving the jig unit U, in which the positional relationships of the multiple third jigs 40 are fixed to the base 50.

[0116] Furthermore, according to the embodiment described above, the unit 1 includes a plurality of jig units corresponding to the configurations (number, arrangement) of the branch pipes T3. With this configuration, the user can align the third flanges F3 all at once by replacing the jig units U with those corresponding to the pipe structures T having various configurations of the branch pipes T3.

[0117] Furthermore, according to the embodiment described above, the configuration of each of the second jig and the third jig is common to the configuration of the first jig, except for the presence or absence and size of the first rotation hole. With this configuration, the unit 1 does not require a jig with a special configuration for each of the main pipe T1, the branch pipe T2, and the branch pipe T3, and can assist in the attachment of the flanges F to the branch pipe T2 and the branch pipe T3, which are connected to the outer circumferential surface of the main pipe T1 at different angles, with a simple configuration of holding the main pipe T1 via the first flange F1 so that each of the central axes L2, L3 is parallel to the horizontal direction.

[0118] ●Flange mounting jig unit (2)● Next, another embodiment of the present unit (hereinafter referred to as the "second embodiment") will be described, focusing on the parts that differ from the previously described embodiment (hereinafter referred to as the "first embodiment"). In the second embodiment, the configuration of the first jig differs from that of the first embodiment. In the following description, elements that are common to the first embodiment and elements that differ from the first embodiment only in their posture (placement and orientation) are given the same symbols, and some or all of the description of these elements will be omitted. In the following description of the present unit, the direction facing the tube structure is the front of the present unit, and the opposite direction is the rear of the present unit.

[0119] ●Configuration of flanged pipe structure (2) FIG. 13 is a perspective view showing a second embodiment of the unit and a flanged pipe structure.

[0120] In the second embodiment, the configuration of the flanged pipe structure TFA differs from the configuration of the flanged pipe structure TF in the first embodiment in the positions of the branch pipe T2 and the branch pipe T3 relative to the bolt hole F1h2, which is the first reference hole, when viewed in the axial direction of the main pipe T1. The positions of the branch pipe T2 and the branch pipe T3 will be described in detail later.

[0121] ●Configuration of flange mounting jig unit (2)

[0122] This unit 1A is an assembly of jigs used by a user of this unit 1A when attaching a flange F to a tube structure T. This unit 1A includes a pair of first jigs 10A, 20A, a second jig 30, a plurality of (three in this embodiment) third jigs 40, a pedestal 50, a base 60, and a tube holding jig 70.

[0123] FIG. 14(a) is a front view of the first jig 10A, and (b) is a right side view of the first jig 10A.

[0124] The first jig 10A is a jig that assists in mounting the first flange F1 to the end T1a of the main pipe T1. The configuration of the first jig 10A is the same as the configuration of the first jig 10 in the first embodiment, except that the first jig 10A has a second rotation hole 10Ah4. That is, the first jig 10A is L-shaped in a side view and is made of a metal such as carbon steel or stainless steel. The first jig 10A has a bottom plate 11, a holding plate 12, a first central hole 10h1, a first mounting hole 10h2, a first rotation hole 10h3, a second rotation hole 10Ah4, and a first fixing member 13.

[0125] The second rotation hole 10Ah4 is a hole through which the first fixing member 13 is passed (screwed) to fix the first flange F1 to the first contact surface 12a when the second flange F2 is attached to the end T2a of the branch pipe T2. In this embodiment, the second rotation hole 10Ah4 includes four second rotation holes 10Ah41 to 10Ah44. The second rotation holes 10Ah41 and 10Ah42 are through holes corresponding to the first fixing members 131 and 132 described later, and the second rotation holes 10Ah43 and 10Ah44 are female screw holes corresponding to the first fixing members 133 and 134 described later. In the following description, each of the second rotation holes 10Ah41 to 10Ah44 will be referred to as the second rotation hole 10Ah4 unless otherwise specified.

[0126] The second rotation holes 10Ah4 are arranged at equal angular intervals (90° intervals in this embodiment) on a virtual circle C1 in a front view. In this embodiment, the second rotation hole 10Ah41 is arranged at a position rotated clockwise by a second angle "θ2" from the corresponding first mounting hole 10h21 around the center point O1 in a front view. Similarly, the second rotation holes 10Ah42-10Ah44 are arranged at positions rotated clockwise by a second angle "θ2" from the corresponding first mounting holes 10h22-10h24. That is, the two second rotation holes 10Ah41, 10Ah42 are arranged at positions symmetrical with respect to the center point O1 of the first central hole 10h1, and the two second rotation holes 10Ah43, 10Ah44 are arranged at positions symmetrical with respect to the center point O1. The second angle "θ2" will be described later. The two second rotation holes 10Ah41, 10Ah42 and the two second rotation holes 10Ah43, 10Ah44 each constitute a pair of second rotation holes in the present invention.

[0127] Fig. 15 is a schematic diagram for explaining the positional relationship of the first rotation hole 10h3 and the second rotation hole 10Ah4 with respect to the first mounting hole 10h2. The figure shows the first jig 10A as seen from the back (as seen in the axial direction of the main pipe T1). For convenience of explanation, the figure also shows the central axes L2 and L3.

[0128] The first angle "θ1" and the second angle "θ2" are determined by the angle (90° or less) between the central axes L2, L3 and the horizontal direction when viewed in the axial direction of the main pipe T1 when the first flange F1 fixed to the first abutment surface 12a by the first fixing member 13 passed through the first mounting hole 10h2 and the bolt hole F1h2 is attached to the end T1a of the main pipe T1. That is, for example, the first angle "θ1" is the same as the angle between the central axis L3 and the horizontal direction, and the second angle "θ2" is the same as the angle between the central axis L2 and the horizontal direction.

[0129] The position of the first rotation hole 10h3 relative to the first mounting hole 10h2 is a position rotated a first angle "θ1" from the position of the first mounting hole 10h2 about the center point O1 so that the central axis L3 is horizontal in rear view. On the other hand, the position of the second rotation hole 10Ah4 relative to the first mounting hole 10h2 is a position rotated a second angle "θ2" from the position of the first mounting hole 10h2 about the center point O1 so that the central axis L2 is horizontal in rear view.

[0130] Here, the second angle "θ2" is different from the angle between the bolt holes F1h2 of the first flange F1 (any of 30°, 45°, and 90°). That is, when the first flange F1 is fixed to the first contact surface 12a by the first fixing member 13 passed through the first mounting hole 10h2 and the bolt hole F1h2, the position of the second rotation hole 10Ah4 differs from the position of each of the bolt holes F1h2 of the first flange F1 in the circumferential direction of the first flange F1 (the circumferential direction of the imaginary circle C1).

[0131] FIG. 16(a) is a front view of the first jig 20A, and (b) is a right side view of the first jig 20A.

[0132] The configuration of the first jig 20A is the same as that of the first jig 10A, except that the left and right directions in a front view are mirror images of the first jig 10A, so details of the configuration of the first jig 20A will be omitted.

[0133] ●Manufacturing method of flanged tube structure (2)● Next, another embodiment of the present method (hereinafter referred to as the "second embodiment") will be described with reference to Figures 1 to 9 and 13 to 16, focusing on the differences from the previously described embodiment (hereinafter referred to as the "first embodiment"). The following description will explain the second embodiment of the present method by taking as an example a case in which a flange F is attached to a tube structure T using the present unit 1A.

[0134] FIG. 17 is a flow chart illustrating a second embodiment of the method. Fig. 18 is a schematic diagram showing the unit 1A, the pipe structure T, and the flange F at each stage of the method. For ease of explanation, Fig. 17 shows the first mounting holes 10h21-24, the first rotating holes 10h31-10h34, and the second rotating holes 10Ah41-10Ah44 with reduced diameters and indicated by "●". In addition, Fig. 17 shows the first fixing members 131-134 with two-dot chain lines. Furthermore, Fig. 17 shows the first jig 10A as viewed from the back (as viewed in the axial direction of the main pipe T1).

[0135] First, similar to the process (S1) of the present method in the first embodiment, the first jig 10A, 20A, the second jig 30, the jig unit U and the pipe holding jig 70 are placed on the base 60 (installation of this unit 1A), and the pipe structure T is held at a predetermined height from the base 60 by the pipe holding jig 70 (S101).

[0136] Next, similarly to the process (S2) of the present method in the first embodiment, the flange F is fixed to the present unit 1A (S102).

[0137] In the following description, the bolt hole F1h2 through which the first fixing members 131, 132 (first fixing members 231, 232) are inserted may be referred to as the first reference hole, and the bolt hole F1h2 through which the first fixing members 133, 134 (first fixing members 233, 234) are inserted may be referred to as the second reference hole.

[0138] Next, similarly to the process (S3) of the present method in the first embodiment, the end portion T1a of the main pipe T1 is inserted into the insertion hole F1h1 of the first flange F1 fixed to the first jig 10A (S103).

[0139] Next, similarly to the process (S4) of the present method in the first embodiment, the end portion T1b of the main pipe T1 is inserted into the insertion hole F1h1 of the first flange F1 fixed to the first jig 20A (S104).

[0140] Next, similar to the process (S5) of the method in the first embodiment, the first jig 20A and the pipe structure T are pushed toward the first jig 10A in the axial direction of the main pipe T1 until the end faces of the ends T1a, T1b of the main pipe T1 relative to the insertion hole F1h1 abut against the corresponding abutment surfaces F1h1b (S105).

[0141] Next, the main pipe T1 is rotated in the circumferential direction of the first flange F1, so that the position of the main pipe T1 is adjusted relative to the circumferential direction of the first flange F1 (bolt holes F1h2) (S106). The position of the main pipe T1 relative to the first flange F1 is determined in advance, for example, in accordance with the piping structure in which the flanged pipe structure TFA is to be installed.

[0142] Next, similarly to the process (S7) of the present method in the first embodiment, the first flanges F1 are welded to the ends T1a, T1b of the main pipe T1 (S107: first flange attachment process).

[0143] Next, similarly to the process (S11) of the present method in the first embodiment, the excess portion of the inner surface weld is smoothed by a grinder or the like (S108).

[0144] Here, in a state where the first flange F1 attached to the main pipe T1 is fixed to the first jig 10A, 20A (first attachment state), the central axis L2 of the branch pipe T2 is inclined at a second angle "θ2" from the horizontal direction, and the central axis L3 of the branch pipe T3 is inclined at a first angle "θ1" from the horizontal direction. Meanwhile, the first rotation holes 10h3, 20h3 are disposed at positions rotated at the first angle "θ1" from the positions of the first mounting holes 10h2, 20h2, and the second rotation holes 10Ah4, 20Ah4 are disposed at positions rotated at the second angle "θ2" from the positions of the first mounting holes 10h2, 20h2.

[0145] Next, the first flange F1 attached to the main pipe T1 is removed from the first jigs 10A and 20A (S109). As a result, the pipe structure T to which the first flange F1 is attached becomes movable.

[0146] Next, the main pipe T1 is rotated in the circumferential direction of the first flange F1 so that the central axis L3 of the branch pipe T3 is aligned along the horizontal direction (parallel to the horizontal direction), thereby aligning the position of the main pipe T1 with respect to the first jigs 10 and 20 (S110: first alignment step). Specifically, the main pipe T1 is rotated in the circumferential direction of the main pipe T1 by a predetermined angle ("θ1") around the central axis L1 of the main pipe T1 so that the first reference hole (bolt hole F1h2) overlaps with the first rotation holes 10h31, 10h32, 20h31, and 20h32 of the first jigs 10A and 20A when viewed in the axial direction of the main pipe T1. At this time, the rollers 72 of the pipe holding jig 70 rotate together with the main pipe T1, allowing the main pipe T1 to rotate smoothly. After the main pipe T1 is rotated, the first flange F1 is fixed to the first jigs 10A and 20A (first rotation and fixation step). That is, for example, in a state where the front surface of the first flange F1 is in contact with the first abutment surface 12a of the first jig 10A, the first fixing members 131, 132 are inserted into the first reference hole and the first rotation holes 10h31, 10h32. As a result, the first flange F1 is positioned at a position where the first reference hole is rotated by the first angle "θ1" from the first mounting holes 10h21, 10h22 in the circumferential direction of the first flange F1 with respect to the first abutment surface 12a. Also, the first fixing members 133, 134 are inserted into the second reference hole and screwed into the first rotation holes 10h33, 10h34. As a result, the first flange F1 is fixed to the first abutment surface 12a of the first jig 10A. Similarly, the first flange F1 is fixed to the first abutment surface 22a of the first jig 20A. At this time, the central axis L3 of the branch pipe T3 is parallel to the horizontal direction. In this manner, the first jigs 10A, 20A can fix the first flanges F1 attached to the ends T1a, T1b, respectively, so that the central axis L3 of the branch pipe T3 is parallel to the horizontal direction. In other words, the first jigs 10A, 20A can hold the main pipe T1 via the first flanges F1 so that the central axis L3 is parallel to the horizontal direction. Here, the process (S110) corresponds to the second alignment step in the first embodiment.

[0147] Next, similarly to the process (S16) of the present method in the first embodiment, the position of the jig unit U (the third jig 40, the base 50) to which the third flange F3 is fixed is adjusted with respect to the tube structure T (S111).

[0148] Next, similarly to the process (S17) of the method in the first embodiment, each end T3a of the branch pipe T3 is inserted into the corresponding insertion hole F3h1 of the third flange F3 (S112).

[0149] Next, similar to the processing (S18) of the method in the first embodiment, the jig unit U (third jig 40, base 50) is pushed toward the branch pipe T3 in the axial direction of the branch pipe T3 until the end face of the end T3a of the branch pipe T3 relative to the insertion hole F3h1 abuts against the abutment surface F3h1b (S113).

[0150] Next, similar to the process (S19) of the method in the first embodiment, the third flange F3 is welded to the end T3a of the branch pipe T3 (S114) similar to the first attachment step, so that the third flange F3 is attached to the end T3a of the branch pipe T3 (third flange attachment step).

[0151] Next, in the same manner as in the process (S20) of the present method in the first embodiment, the excess portion of the inner surface weld is smoothed by a grinder or the like (S115), in the same manner as in the first flange F1.

[0152] Here, when the third flange F3 attached to the branch pipe T3 is fixed to the third jig 40 (second mounting state), the central axis L3 of the branch pipe T3 is parallel to the horizontal direction, and the central axis L2 of the branch pipe T2 is inclined at a predetermined angle (in this embodiment, the angle "|θ1+θ2|") from the horizontal direction.

[0153] Next, similarly to the process (S21) of the method in the first embodiment, the third flange F3 attached to the branch pipe T3 and the first flange F1 attached to the main pipe T1 are removed from the first jigs 10A, 20A and the third jig 40 (S116). As a result, the pipe structure T to which the first flange F1 is attached becomes movable.

[0154] Next, the main pipe T1 is rotated in the circumferential direction of the first flange F1 so that the central axis L2 of the branch pipe T2 is aligned along the horizontal direction (parallel to the horizontal direction), thereby aligning the position of the main pipe T1 with respect to the first jigs 10A and 20A (S117: second alignment step). Specifically, the main pipe T1 is rotated in the circumferential direction of the main pipe T1 by a predetermined angle (|θ1+θ2|) around the central axis L1 of the main pipe T1 so that the first reference hole (bolt hole F1h2) overlaps with the second rotation holes 10Ah41, 10Ah42, 20Ah41, and 20Ah42 of the first jigs 10A and 20A when viewed in the axial direction of the main pipe T1. At this time, the rollers 72 of the pipe holding jig 70 rotate together with the main pipe T1, allowing the main pipe T1 to rotate smoothly. After the main pipe T1 is rotated, the first flange F1 is fixed to the first jig 10A, 20A (second rotation and fixing step). Specifically, with the front surface of the first flange F1 in contact with the first abutment surface 12a of the first jig 10, the first fixing members 131, 132 are inserted into the first reference hole and the second rotation holes 10Ah41, 10Ah42. As a result, the first flange F1 is positioned at a position where the first reference hole is rotated by a second angle "θ2" from the first mounting holes 10h21, 10h22 in the circumferential direction of the first flange F1 with respect to the first abutment surface 12a. In addition, the first fixing members 133, 134 are inserted into the second reference hole and screwed into the second rotation holes 10Ah43, 10Ah44. As a result, the first flange F1 is fixed to the first abutment surface 12a of the first jig 10A. Similarly, the first flange F1 is fixed to the first abutment surface 22a of the first jig 20A. At this time, the central axis L2 of the branch pipe T2 is parallel to the horizontal direction. In this manner, the first jigs 10A and 20A can fix the first flanges F1 attached to the ends T1a and T1b, respectively, so that the central axis L2 of the branch pipe T2 is parallel to the horizontal direction. In other words, the first jigs 10A and 20A can hold the main pipe T1 via the first flange F1 so that the central axis L2 is parallel to the horizontal direction. Here, the process (S117) corresponds to the first alignment process in the first embodiment.

[0155] Next, similarly to the process (S7) of the present method in the first embodiment, the position of the second jig 30 to which the second flange F2 is fixed is adjusted with respect to the tube structure T (S118).

[0156] Next, similarly to the process (S8) of the present method in the first embodiment, the end portion T2a of the branch pipe T2 is inserted into the insertion hole F2h1 of the second flange F2 (S119).

[0157] Next, similar to the process (S9) of the method in the first embodiment, the second jig 30 is pushed toward the branch pipe T2 in the axial direction of the branch pipe T2 until the end face of the end T2a of the branch pipe T2 relative to the insertion hole F2h1 abuts against the corresponding abutment surface F2h1b (S120).

[0158] Next, similarly to the process (S12) of the method in the first embodiment, the second flange F2 is welded to the end T2a of the branch pipe T2 (S121), so that the second flange F2 is attached to the end T2a of the branch pipe T2 (second flange attachment process).

[0159] Next, similarly to the process (S13) of the present method in the first embodiment, the excess portion of the inner surface weld is smoothed by a grinder or the like (S122).

[0160] Here, when the second flange F2 attached to the branch pipe T2 is fixed to the second jig 30 (third mounting state), the central axis L2 of the branch pipe T2 is parallel to the horizontal direction, and the central axis L3 of the branch pipe T3 is inclined at an angle "θ1 + θ2" from the horizontal direction.

[0161] Next, the second flange F2 attached to the branch pipe T2 and the first flange F1 attached to the main pipe T1 are removed from the unit 1A (the first jigs 10A and 20A and the second jig 30) (S123). As a result, the pipe structure T to which all the flanges F are attached (i.e., the flanged pipe structure TFA) is removed from the unit 1. Thereafter, the flanged pipe structure TFA is subjected to an inner surface coating as necessary.

[0162] Thus, the method includes a first flange mounting step, a first alignment step, a third flange mounting step, a second alignment step, and a second flange mounting step. In this configuration, a user can easily mount the first flange F1 at an appropriate position relative to the ends T1a and T1b of the main pipe T1. In addition, a user can easily position and mount the second flange F2 at an appropriate position relative to the end T2a of the branch pipe T2 by rotating the pipe structure T so that the central axis L2 is parallel to the horizontal direction and fixing the pipe structure T to the first jig 10A or 20A. Similarly, a user can easily position and mount the third flange F3 at an appropriate position relative to the end T3a of the branch pipe T3 by rotating the pipe structure T so that the central axis L3 is parallel to the horizontal direction and fixing the pipe structure T to the first jig 10A or 20A. That is, this method can assist in the attachment of the flange F to the branch pipe T2 and the branch pipe T3 which are connected to the outer circumferential surface of the main pipe T1 at different angles.

[0163] The second flange and the third flange in the present invention may be fixed to the second jig and the third jig when the positions of the second jig and the third jig are adjusted, respectively.

[0164] In order to improve the rotation efficiency of the flange attachment using this unit, temporary welding of only the outer surface may be performed in steps (S107, S114, S121), and inner surface welding may be performed after step (S123). In this case, steps (S108, S115, S122) may be performed consecutively or simultaneously after the inner surface welding.

[0165] Summary (2) According to the embodiment described above, the unit 1A includes the first jigs 10A and 20A, the second jigs 30, and the third jigs 40. When viewed in the axial direction of the main pipe T1, the second jigs 30 and the third jigs 40 are disposed on the sides of the main pipe T1. The first jigs 10A and 20A can hold the main pipe T1 via the first flange F1 so that the central axis L2 of the branch pipe T2 is parallel to the horizontal direction, and can hold the main pipe T1 via the first flange F1 so that the central axis L3 of the branch pipe T3 is parallel to the horizontal direction. According to this configuration, the user can attach the second flange F2 to the end T2a of the branch pipe T2 using the second jig 30 by orienting the central axis L2 parallel to the horizontal direction toward the second jig 30 disposed on one side of the main pipe T1. Meanwhile, the user can orient the central axis L3 parallel to the horizontal direction toward the third jig 40 arranged on the other side of the main pipe T1, and use the third jig 40 to attach the third flange F3 to the end T3a of the branch pipe T3. That is, with a simple configuration in which the unit 1A holds the main pipe T1 via the first flange F1 so that the central axes L2, L3 are each parallel to the horizontal direction, it can assist in the attachment of the flanges F to the branch pipe T2 and branch pipe T3, which are connected to the outer circumferential surface of the main pipe T1 at different angles.

[0166] Furthermore, according to the embodiment described above, each of the first jigs 10A, 20A includes a first abutment surface 12a, 22a parallel to the vertical direction, a first central hole 10h1, 20h1, a pair of first mounting holes 10h2, 20h2 arranged on the same imaginary circle as the first central holes 10h1, 20h1, a pair of first rotation holes 10h3, 20h3, and a pair of second rotation holes 10Ah4, 20Ah4, and a first fixing member 13, 23. When the positions of the first mounting holes 10h2 and the bolt holes F1h2 serving as the first and second reference holes coincide with each other in the axial view of the main pipe T1, and the central axis L2 is parallel to the horizontal direction, the first rotation holes 10h3 and 20h3 are disposed in positions rotated by a first angle "θ1" from the positions of the bolt holes F1h2 serving as the first reference hole and the bolt holes F1h2 serving as the second reference hole among the multiple bolt holes F1h2, respectively, in the axial view. On the other hand, the second rotation holes 10Ah4 and 20Ah4 are disposed in positions rotated by a second angle "θ2" from the positions of the bolt holes F1h2 serving as the first reference hole and the bolt holes F1h2 serving as the second reference hole among the multiple bolt holes F1h2, respectively, in the axial view. According to this configuration, the user can easily make the central axis L3 parallel to the horizontal direction by passing the first fixing members 13, 23 through the bolt holes (first reference holes) F1h2 and the first rotation holes 10h3, 20h3 through which the first fixing members 13, 23 were passed when the first flange F1 was attached to the ends T1a, T1b of the main pipe T1. On the other hand, the user can easily make the central axis L2 parallel to the horizontal direction by passing the first fixing members 13, 23 through the bolt holes (first reference holes) F1h2 and the second rotation holes 10Ah4, 20Ah4 through which the first fixing members 13, 23 were passed when the first flange F1 was attached to the ends T1a, T1b of the main pipe T1. In other words, this unit 1A has a simple configuration in which the first jig 10A, 20A has a first rotation hole 10h3, 20h3 corresponding to the first angle "θ1" and a second rotation hole 10Ah4, 20Ah4 corresponding to the second angle "θ2", thereby making the central axes L2, L3 parallel to the horizontal direction and assisting in the installation of the flange F to the branch pipe T2 and branch pipe T3 that are connected at different angles to the outer peripheral surface of the main pipe T1.

[0167] Further, according to the embodiment described above, the first rotation holes 10h3, 20h3 are disposed at positions rotated by the first angle "θ1" from the positions of the first mounting holes 10h2, 20h2 about the center point O1 of the first central holes 10h1, 20h1. Meanwhile, the second rotation holes 10Ah4, 20Ah4 are disposed at positions rotated by the second angle "θ2" from the positions of the first mounting holes 10h2, 20h2 about the center point O1. According to this configuration, the user can easily make the central axis L3 parallel to the horizontal direction by passing the first fixing members 13, 23 through the bolt holes (first reference holes) F1h2 and the first rotation holes 10h3, 20h3 through which the first fixing members 13, 23 were passed when the first flange F1 was attached to the ends T1a, T1b of the main pipe T1. On the other hand, the user can easily make the central axis L2 parallel to the horizontal direction by passing the first fixing members 13, 23 through the bolt holes (first reference holes) F1h2 and the second rotation holes 10Ah4, 20Ah4 through which the first fixing members 13, 23 were passed when the first flange F1 was attached to the ends T1a, T1b of the main pipe T1. That is, the user can perform the first and second rotation and fixing steps using only the first and second reference holes out of the multiple bolt holes F1h2. Therefore, the user can perform the first and second rotation and fixing steps quickly and without error.

[0168] Furthermore, according to the embodiment described above, when the first flange F1 is fixed to the first abutment surface 12a, 22a by the first fixing members 13, 23 passed through the first mounting holes 10h2, 20h2 and the bolt holes F1h2, the positions of the first rotation holes 10h3, 20h3 and the second rotation holes 10Ah4, 20Ah4 are different from the position of the bolt holes F1h2 of the first flange F1 in the circumferential direction of the first flange F1 (the circumferential direction of the imaginary circle C1). According to this configuration, the first rotation holes 10h3, 20h3 and the second rotation holes 10Ah4, 20Ah4 can be disposed at any angle with respect to the first mounting holes 10h2, 20h2 that is different from the angle between the bolt holes F1h2 of the first flange F1. As a result, the unit 1 can fix the tube structure T so that the central axes L2, L3, which are oriented at an angle different from the angle between the bolt holes F1h2 with respect to the horizontal direction, are parallel to the horizontal direction.

[0169] Furthermore, according to the embodiment described above, when the first flange F1 attached to the main pipe T1 is fixed to the first jig 10A, 20A so that the central axis L2 is parallel to the horizontal direction (when the central axis L2 is parallel to the horizontal direction), the second abutment surface 32a is arranged parallel to the opening surface of the end T2a of the branch pipe T2, and the central axis L2 is directed to the center point O3 of the second central hole 30h1. With this configuration, the user can easily align the second flange F2 with the end T2a by pushing the second jig 30 toward the end T2a.

[0170] Furthermore, according to the embodiment described above, when the first flange F1 attached to the main pipe T1 is fixed to the first jig 10A, 20A so that the central axis L3 is parallel to the horizontal direction, the third abutment surface 42a is arranged parallel to the opening surface of the end T3a of the branch pipe T3, and the central axis L3 is directed to the center point O4 of the third central hole 40h1. With this configuration, the user can easily align the third flange F3 with the end T3a by pushing the third jig 40 toward the end T3a.

[0171] Furthermore, according to the embodiment described above, the third abutment surfaces 42a of the multiple (three) third jigs 40 are arranged on the same imaginary plane. With this configuration, the user can align each of the multiple third flanges F3 with the end surface of the end T3a of the corresponding branch pipe T3 all at once. Even if the lengths of the branch pipes T3 differ to the extent that the attachment of the third flanges F3 is not hindered, the user can attach each third flange F3 to the end T3a of the branch pipe T3 with the third flanges F3 aligned on the same imaginary plane.

[0172] Furthermore, according to the embodiment described above, the multiple third jigs 40 and the base 50 configure an integrated jig unit U. With this configuration, the user can move all of the third jigs 40 while keeping the positional relationships of the multiple third jigs 40 fixed, simply by moving the jig unit U, in which the positional relationships of the multiple third jigs 40 are fixed to the base 50.

[0173] Furthermore, according to the embodiment described above, the unit 1 includes a plurality of jig units corresponding to the configurations (number, arrangement) of the branch pipes T3. With this configuration, the user can align the third flanges F3 all at once by replacing the jig units U with those corresponding to the pipe structures T having various configurations of the branch pipes T3.

[0174] Furthermore, according to the embodiment described above, each of the first jigs 10A, 20A includes a first abutment surface 12a, 22a, a first central hole 10h1, 20h1, a pair of first mounting holes 10h2, 20h2, a pair of first rotation holes 10h3, 20h3, a pair of second rotation holes 10Ah4, 20Ah4, and a first fixing member 13. When the first flange F1 fixed to the first abutment surface 12a, 22a by the first fixing member 13 passed through the first mounting holes 10h2, 20h2 and the bolt hole F1h2 is attached to the ends T1a, T1b of the main pipe T1, when viewed in the axial direction of the main pipe T1, the first rotation holes 10h3, 20h3 are positioned at a position rotated by a first angle "θ1" from the position of the first mounting holes 10h2, 20h2, and the second rotation holes 10Ah4, 20Ah4 are positioned at a position rotated by a second angle "θ2" from the position of the first mounting holes 10h2, 20h2. According to this configuration, the unit 1A has a simple configuration in which the first jig 10A, 20A has a first rotation hole 10h3, 20h3 corresponding to the first angle "θ1" and the second rotation hole 10Ah4, 20Ah4 corresponding to the second angle "θ2", which makes the central axes L2, L3 parallel to the horizontal direction and assists in the attachment of the flange F to the branch pipe T2 and branch pipe T3 that are connected at different angles to the outer peripheral surface of the main pipe T1.

[0175] ●Other embodiments● The configuration of the flanged pipe structure according to the present invention is not limited to the above-described embodiments. That is, for example, the flanged pipe structure according to the present invention may include a plurality of branch pipes, or may include one or more branch pipes instead of the branch pipes. For example, the number of branch pipes in the present invention may be "2" or less, or "4" or more. Furthermore, for example, the lengths of the branch pipes may be different.

[0176] In each of the embodiments described above, the branch pipe may function as the first branch pipe in the present invention, and the branch pipe may function as the second branch pipe in the present invention. In this case, for example, in each of the embodiments, the second jig functions as the third jig in the present invention, and the third jig functions as the second jig in the present invention.

[0177] Furthermore, in each of the above-described embodiments, the positions of the branch pipe and the branch pipe may be interchanged when viewed in the axial direction of the main pipe. In this case, for example, when viewed in the axial direction of the main pipe, the second jig and the third jig for the pipe structure are disposed in positions opposite to those in each of the above-described embodiments.

[0178] Furthermore, in each of the above-described embodiments, the central axis of each of the branch pipes and the branch pipes in the present invention may intersect with the central axis of the main pipe at an acute angle (obtuse angle) when viewed from the side of the main pipe, as long as the central axis of each of the branch pipes and the branch pipes in the present invention intersect with the central axis of the main pipe at an acute angle (obtuse angle).

[0179] Furthermore, in each of the embodiments described above, the angle between the central axes of the branch pipe and the branch pipe in the present invention may be an acute angle.

[0180] Furthermore, in each of the above-described embodiments, the flange of the present invention may be any flange that can be attached to the end of a cylindrical pipe, and the configuration is not limited to the present embodiment. That is, for example, the flange of the present invention may be various flanges (e.g., plate flanges) that comply with JIS (Japanese Industrial Standards). In this configuration, for example, in step (S5), the position of the end face of the end of the main pipe relative to the insertion hole is visually aligned to an appropriate position (a position that can be welded), and in step (S11), the excess portion of the inner weld is R-chamfered with a grinder or the like.

[0181] Furthermore, the numbers of bolt holes in the first to third flanges are not limited to those in the respective embodiments. That is, for example, the number of bolt holes in the third flange may be the same as the number of bolt holes in the first flange (12).

[0182] Furthermore, the arrangement of the first rotation hole in the present invention only needs to correspond to the direction in which the central axis of the branch pipe in the present invention is oriented, and is not limited to that in the first embodiment. That is, for example, the first rotation hole in the present invention may be arranged in the clockwise direction from the first mounting hole in the front view.

[0183] Furthermore, the arrangement of the first rotation hole and the second rotation hole in the present invention only needs to correspond to the direction in which the central axis of the branch pipe and the branch pipe in the present invention are oriented, and is not limited to the second embodiment. That is, for example, the second rotation hole in the present invention may be arranged side by side with the first rotation hole in the counterclockwise direction from the first mounting hole in a front view.

[0184] Furthermore, in each of the embodiments described above, the first mounting hole, first rotation hole, and second rotation hole of the present invention may be arranged in pairs (point-symmetrical with respect to the center point) on the extension of the diameter line of the first central hole, and the number of these may be two. Similarly, the number of the second mounting holes and third mounting holes of the present invention may be two. In this case, the first fixing member, second fixing member, and third fixing member of the present invention may each be composed of only a reamer bolt.

[0185] Furthermore, in the second embodiment described above, the first jig in the present invention may have a third rotation hole (third rotation hole) at a position different from the first and second rotation holes. In this case, the third rotation hole is disposed at a position rotated by a third angle (an angle different from the first angle and the second angle) between the second or third central axis and the horizontal direction, for example.

[0186] Furthermore, in the first embodiment described above, the first jig of the present invention may have a plurality of types of first rotation holes. That is, for example, the first jig of the present invention may have three types of first rotation holes arranged at positions rotated by first angles "θ1", "θ11", and "θ12" from the first mounting hole. In this configuration, the first jig of the present invention can also be used for two types of pipe structures in which the branch pipes protrude in different directions from the first embodiment.

[0187] Furthermore, in the second embodiment described above, the first jig of the present invention may include a plurality of types of first rotation holes and second rotation holes. That is, for example, the first jig of the present invention may include two types of first rotation holes arranged at positions rotated by a first angle "θ1" and "θ11" from the first mounting hole, and two types of second rotation holes arranged at positions rotated by a second angle "θ2" and "θ21" from the first mounting hole. In this configuration, the first jig of the present invention can also be used for three types of pipe structures in which the protruding direction of at least one of the branch pipe and the branch pipe is different from that of the second embodiment.

[0188] Furthermore, in each of the embodiments described above, the first fixing member, the second fixing member and the third fixing member of the present invention may each be constituted solely by a bolt having a fully threaded portion.

[0189] Furthermore, in each of the embodiments described above, the first jig, the second jig and the third jig (jig unit) of the present invention may each be attached to a base so as to be slidable relative to the tube structure.

[0190] Furthermore, in each of the above-described embodiments, the first jig of the present invention may include a "U"-shaped plate-shaped holding plate with two plate-shaped arms facing upward. In this case, the distance between the two arms is greater than the outer diameter of the main pipe. In this case, the crotch of the two arms functions as a central hole, and the main pipe can be removed upward from between the two arms. In this configuration, the first flange may be attached to the back side of the first jig.

[0191] Furthermore, in each of the embodiments described above, the inner diameter of the first central hole (second central hole, third central hole) in the present invention may be large enough to enable a user to perform specified work (e.g., alignment and inner surface welding, as described below), and may be equal to or smaller than the inner diameter of the insertion hole of the corresponding main pipe (branch pipe, branch pipe).

[0192] Furthermore, in each of the above-described embodiments, the first jig in the present invention may have an arc-shaped long hole that also functions as the first mounting hole and the first rotation hole (and the second rotation hole). In other words, the first mounting hole and the first rotation hole (and the second rotation hole) may be integrally configured as an arc-shaped long hole. With this configuration, the user can rotate the first flange and the main pipe at any angle within the long hole. At this time, the user can rotate the first flange and the main pipe by loosening the first fixing member and sliding the first fixing member within the long hole without removing the first fixing jig. As a result, the workability of this unit is improved. Furthermore, this unit can be adapted to a plurality of types of pipe structures having different first and second angles with a pair of first jigs.

[0193] Furthermore, in the above-described configuration of the long hole, both ends of the long hole may function as two of the attachment hole and the first rotation hole (second rotation hole). With this configuration, the user can position the first flange simply by sliding the fixing member inside the long hole until it abuts against both ends of the long hole.

[0194] Furthermore, in each of the above-described embodiments, when the positions of the first mounting holes and the positions of the bolt holes of the first flange are aligned in the axial view of the main pipe T1 in the first mounting state, and the central axis of the branch pipe is parallel to the horizontal direction, the arrangement of the first rotation hole in the present invention may be a position rotated by the first angle "θ1" from any of the positions of the multiple bolt holes around the center point of the first central hole in the axial view of the main pipe T1, and is not limited to a position rotated by the first angle "θ1" from each of the positions of the bolt hole that is the first reference hole and the bolt hole that is the second reference hole. That is, for example, the first rotation hole in the present invention may be arranged at a position rotated by the first angle "θ1" from the position of the bolt hole next to the bolt hole that is the first reference hole. In this configuration, the position of the first rotation hole is not limited to a position rotated by the first angle "θ1" from the position of the first mounting hole, and for example, the first rotation hole can be arranged so as to be adjacent to the first mounting hole. That is, in the first jig, regardless of the magnitude of the first angle "θ1," the first mounting hole and the first rotation hole can be arranged adjacent to each other within an angular range smaller than the first angle "θ1." As a result, various rotation holes can be arranged in a concentrated manner within a more adjacent range.

[0195] Furthermore, in each of the above-described embodiments, the position of the first mounting hole in the present invention only needs to be located on an imaginary circle concentric with the central hole, and is not limited to being above, below, left, or right of the central hole. In other words, for example, the first mounting hole in the present invention may be located based on the position of a branch pipe or a branch pipe relative to the piping structure.

[0196] Furthermore, in each of the above-described embodiments, the unit does not need to include a base. That is, the third jig in the present invention does not need to constitute a jig unit. In this case, each of the third jigs is individually attached to a base and individually adjusted in position.

[0197] Furthermore, in the second embodiment described above, a third flange may be attached to an end of a branch pipe after a second flange is attached to an end of the branch pipe. That is, for example, in the first alignment step, the position of the main pipe relative to the first jig may be aligned so that the central axis of the branch pipe is aligned horizontally, and in the second alignment step, the position of the main pipe relative to the first jig may be aligned so that the central axis of the branch pipe is aligned horizontally.

[0198] Furthermore, in each of the embodiments described above, the pipe holding jig may be provided with a semicircular surface having an inner diameter substantially the same as the outer diameter of the main pipe, instead of the roller. [Explanation of symbols]

[0199] 1 Flange mounting jig unit 10 First jig 10h1 1st center hole 10h2 First mounting hole 10h3 1st Rotary Hole 12a 1st contact surface 13 First fixing member 20 First jig 20h1 1st center hole 20h2 1st mounting hole 20h3 1st Rotary Hole 22a 1st contact surface 23 First fixing member 30 Second jig 30h1 2nd center hole 32a Second contact surface 40 Third jig 40h1 3rd center hole 42a 3rd contact surface 50 Pedestal U Jig Unit FT Flanged Tube Structure F flange F1 First flange F1h1 Insertion hole (first insertion hole) F1h2 bolt hole (first bolt hole) F2 Second flange F2h1 Insertion hole (Second insertion hole) F3 3rd flange F3h1 Insertion hole (third insertion hole) T-tube structure T1 Main pipe (body) T1a end (first end) T1b end (second end) T2 Branch pipe (first branch pipe body) T2a end T3 Branch (Second Branch) T3a end 1A Flange mounting jig unit 10A First Jig 10Ah4 2nd Rotary Hole 20A Second jig 20Ah4 2nd Rotary Hole

Claims

1. A flange mounting jig unit used for mounting a flange to a pipe structure, comprising: The tube structure includes: A cylindrical tube; A first branch pipe body connected to an outer peripheral surface of the pipe body; a second branch pipe body connected to the outer circumferential surface in a direction different from that of the first branch pipe body; Including, The flange is a first flange attached to each of the first and second ends of the tube; a second flange attached to an end of the first branch pipe; a third flange attached to an end of the second branch pipe; Including, The flange mounting jig unit includes: a pair of first jigs that assist in attaching the first flange to the first end and the second end of the pipe; a second jig that assists in attaching the second flange to the end of the first branch pipe; a third jig that assists in attaching the third flange to the end of the second branch pipe; and When viewed in the axial direction of the tube, The second jig and the third jig are each disposed on a side of the tube, the first jig is capable of holding the tube via the first flange such that a first central axis of the first branch tube is parallel to a horizontal direction, and is capable of holding the tube via the first flange such that a second central axis of the second branch tube is parallel to the horizontal direction. A flange mounting jig unit.

2. The first flange is a first insertion hole into which the end of the tube is inserted; a plurality of first bolt holes arranged at equal angular intervals radially outward from the first insertion hole; Equipped with Each of the first jigs is a first abutment surface that is parallel to a vertical direction and that is configured to abut against the first flange; A first central hole is disposed on the first contact surface and configured to communicate with the first insertion hole; a pair of first mounting holes and a pair of first rotation holes, the pair of first mounting holes and the pair of first rotation holes being arranged on a virtual circle concentric with the first central hole and at positions point-symmetrical with respect to a center point of the first central hole, in the first contact surface; a first fixing member configured to be passed through the first mounting hole or the first rotation hole and any one of the first bolt holes of the first flange to fix the first flange to the first contact surface; Equipped with When the first flange is attached to the first end and the second end of the pipe body, when viewed in the axial direction, the positions of each of the pair of first mounting holes coincide with the positions of two of the first bolt holes, and the first central axis is parallel to the horizontal direction, When viewed in the axial direction, the first rotation hole is disposed at a position rotated from any one of the plurality of first bolt holes by a first angle between the second central axis and the horizontal direction, with the center point of the first central hole as a center.

2. The flange mounting jig unit according to claim 1.

3. When viewed in the axial direction, the first rotation hole is disposed at a position rotated by the first angle from the position of the first mounting hole around the center point of the first central hole.

3. The flange mounting jig unit according to claim 2.

4. When the first flange is fixed to the first contact surface by the first fixing member that is passed through the first mounting hole and the first bolt hole, In the circumferential direction of the virtual circle, a position of the first rotation hole is different from a position of the first bolt hole of the first flange.

4. A flange mounting jig unit according to claim 2 or 3.

5. The first mounting hole and the first rotation hole are integrally formed as an arc-shaped elongated hole.

5. A flange mounting jig unit according to claim 2.

6. Both ends of the long hole function as the first mounting hole and the first rotation hole.

6. A flange mounting jig unit according to claim 5.

7. The second flange is a second insertion hole into which the end of the first branch pipe body is inserted; Equipped with The second jig is a second abutment surface that is parallel to the vertical direction and that is configured to abut against the second flange; A second central hole is disposed on the second contact surface and configured to communicate with the second insertion hole; Equipped with When the first central axis is parallel to the horizontal direction, The second abutment surface is disposed parallel to an opening surface of the end of the first branch pipe body, The first central axis is directed toward a center point of the second central hole.

7. A flange mounting jig unit according to claim 1.

8. The third flange is a third insertion hole into which the end of the second branch pipe body is inserted; Equipped with The third jig is a third abutment surface that is parallel to the vertical direction and that is configured to abut against the third flange; a third central hole disposed on the third contact surface and configured to communicate with the third insertion hole; Equipped with When the first flange attached to the pipe body is fixed to the first jig so that the second central axis is parallel to the horizontal direction, the third contact surface is disposed parallel to an opening surface of the end of the second branch pipe body, The second central axis is directed toward a center point of the third central hole.

8. A flange mounting jig unit according to claim 1.

9. A plurality of the second branch pipes are connected to the outer peripheral surface of the pipe body, A plurality of the third jigs corresponding to a plurality of the second branch pipe bodies; and The third contact surfaces of the plurality of third jigs are disposed on the same virtual plane.

9. The flange mounting jig unit according to claim 8.

10. A base on which a plurality of the third jigs are attached; and The plurality of third jigs and the base constitute an integral jig unit. The flange mounting jig unit according to claim 9.

11. There are a plurality of configurations of the second branch pipe bodies with respect to the pipe body, A plurality of the jig units corresponding to a plurality of the configurations; and The plurality of jig units are interchangeable with each other. The flange mounting jig unit according to claim 10.

12. The first flange is a first insertion hole into which the end of the tube is inserted; a plurality of first bolt holes arranged at equal angular intervals radially outward from the first insertion hole; Equipped with Each of the first jigs is a first abutment surface that is parallel to a vertical direction and that is configured to abut against the first flange; A first central hole is disposed on the first contact surface and configured to communicate with the first insertion hole; a pair of first mounting holes, a pair of first rotation holes, and a pair of second rotation holes, which are arranged on a virtual circle concentric with the first central hole and at positions point-symmetrical with respect to a center point of the first central hole, on the first contact surface; a first fixing member configured to be passed through the first mounting hole, the first rotation hole or the second rotation hole and any one of the first bolt holes of the first flange to fix the first flange to the first contact surface; Equipped with When the first flange is attached to the end of the pipe body, the first flange is fixed to the first contact surface by the first fixing member passed through the first mounting hole and the first bolt hole, and the first flange is attached to the end of the pipe body, as viewed in the axial direction of the pipe body, the first rotation hole is disposed at a position rotated from the position of the first mounting hole by a first angle between the second central axis and the horizontal direction, the second rotation hole is disposed at a position rotated from the position of the first mounting hole by a second angle between the first central axis and the horizontal direction.

2. The flange mounting jig unit according to claim 1.

13. A method for manufacturing a flanged pipe structure using a flange mounting jig unit used for mounting a flange to a pipe structure, comprising the steps of: The tube structure includes: A cylindrical tube; a first branch pipe body protruding from an outer circumferential surface of the pipe body in a radial direction of the pipe body; a second branch pipe body protruding from the outer circumferential surface in the radial direction different from that of the first branch pipe body; Including, The flange is a first flange attached to each of the first and second ends of the tube; a second flange attached to an end of the first branch pipe; a third flange attached to an end of the second branch pipe; Including, The flange mounting jig unit includes: a pair of first jigs that assist in attaching the first flange to the first end and the second end of the pipe; a second jig that assists in attaching the second flange to the end of the first branch pipe; a third jig that assists in attaching the third flange to the end of the second branch pipe; and The method for manufacturing the flanged tube structure includes the steps of: a first flange attachment step of attaching the first flange fixed to the first jig to the first end portion and the second end portion of the pipe body, respectively; a first alignment step of aligning the pipe body with respect to the first jig so that a first central axis of the first branch pipe body is aligned along a horizontal direction; a second flange attachment step of attaching the second flange fixed to the second jig to the end portion of the first branch pipe body; a second alignment step of aligning the pipe body with respect to the first jig so that a second central axis of the second branch pipe body is aligned along the horizontal direction; a third flange attachment step of attaching the third flange fixed to the third jig to the end portion of the second branch pipe body; Including, 4. A method for manufacturing a flanged tube structure comprising the steps of:

14. The method for manufacturing the flanged tube structure includes the steps of: a holding step in which the first branch pipe body is held by the second flange; Including, The holding step is performed after the first alignment step. The method for producing the flanged tube structure according to claim 13.

15. each of the first flange mounting step and the second flange mounting step is performed after the first alignment step; The second alignment step includes: This is performed after the first flange mounting step and the second flange mounting step, a rotating and fixing step of rotating the first flange attached to the pipe body so that the second central axis is aligned along the horizontal direction, and then fixing the first flange to the first jig; Including, A method for manufacturing a flanged tube structure according to claim 13 or 14.

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