Resin jointing pipe, connecting pipe, resin pipe joining method, and support device for resin pipe joining

Abstract

This invention provides a configuration that allows resin pipes, formed by extending at least the end portion including the joint in the circumferential direction, to be joined in the axial direction. [Solution] The resin jointed pipe 1 is a resin jointed pipe in which two resin pipes P, P are joined by heat welding. At least one of the two joined resin pipes P, P is formed by stretching and expanding the diameter of at least the end including the joint portion in the circumferential direction. The two resin pipes P, P are joined by heating the two resin pipes P, P while the joint portion of at least one of the resin pipes is supported from the inside by the connecting pipe 10.

Description

Technical Field

[0001] The present invention relates to a resin joint pipe in which two resin pipes are connected by heat welding, a connecting pipe for connecting two resin pipes by heat welding, a method for joining resin pipes, and a support device for resin pipe joining.

Background Art

[0002] There is known a resin joint pipe in which two resin pipes are connected by heat welding. In such a resin joint pipe, the two resin pipes are connected by heat welding using, for example, an electric fusion joint. For example, Patent Document 1 discloses an electric fusion joint in which an electric heating wire is inserted into a spiral groove formed on the inner peripheral surface of a resin pipe. In this electric fusion joint, by energizing the electric heating wire from a pair of terminals provided on the outer peripheral surface of the electric fusion joint, the outer peripheral surface of the resin pipe inserted into the resin pipe and the inner surface of the connecting pipe are melted and heat welded.

[0003] On the other hand, as a resin pipe, a biaxially oriented pipe manufactured by stretching the pipe in the axial direction and the circumferential direction is known. As such a biaxially oriented pipe, Patent Document 2 discloses a biaxially oriented polyethylene pipe manufactured by stretching a polyethylene pipe in the axial direction and the circumferential direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the case of a biaxially oriented tube as disclosed in Patent Document 2, the tube is stretched axially and circumferentially while being heated, and then rapidly cooled to fix it to the stretched size, leaving internal strain. Therefore, if it is heated above a predetermined temperature after stretching, it will shrink in an attempt to return to its original size. Consequently, when a biaxially oriented tube as disclosed in Patent Document 2 is heat-welded using an electrofusion joint as disclosed in Patent Document 1, the biaxially oriented tube shrinks radially relative to the electrofusion joint, causing the electrofusion joint and the end of the biaxially oriented tube to separate radially. As a result, there is a possibility that the biaxially oriented tube cannot be sufficiently heat-welded by the electrofusion joint.

[0006] In response to this, there is a need for a configuration that allows for the axial joining of resin pipes, which are formed by extending and expanding the diameter of at least the end portion including the joint in the circumferential direction.

[0007] The object of the present invention is to realize a configuration that allows resin pipes, formed by expanding the diameter of at least the end portion including the joining portion by circumferential stretching, to be joined in the axial direction. [Means for solving the problem]

[0008] A resin-jointed pipe according to one embodiment of the present invention is a resin-jointed pipe in which a resin pipe is joined to a pipe. The joined resin pipe is formed by expanding the diameter of at least the end portion including the joint portion by circumferential stretching. The resin pipe is joined to the support member or the pipe by heating while the joint portion is supported from the inside by the support member (first configuration).

[0009] If the resin pipe to be joined to the main pipe is a resin pipe in which at least the end including the joining portion is stretched in the circumferential direction and its diameter is enlarged, then when the resin pipe is joined to the main pipe by heat welding, the joining portion of the resin pipe will shrink in diameter due to the heat because it is the portion that has been stretched in the circumferential direction and its diameter is enlarged.

[0010] In contrast, as described above, by joining the resin pipe to the pipe or the support while supporting the joint portion of the resin pipe from the inside with a support member, it is possible to suppress the reduction in diameter of the joint portion of the resin pipe. Therefore, a resin pipe whose end portion, including the joint portion, is circumferentially stretched and enlarged in diameter can be joined to another pipe or support by heating.

[0011] The first configuration further includes a connecting pipe which is configured to have less radial deformation due to heat compared to the resin pipe, and which functions as the support member by being located inside the end of the resin pipe and supporting the resin pipe from the inside, and whose outer surface is joined to the inner surface of the resin pipe by heating (second configuration).

[0012] This allows the pipe and the resin pipe to be joined by the connecting pipe, and the joining portion of the resin pipe is supported from the inside of the resin pipe, thereby preventing the joining portion of the resin pipe, which has been expanded in diameter by circumferential extension at least at the end including the joining portion, from shrinking in diameter. Therefore, the resin pipe can be joined to another pipe by heating.

[0013] Furthermore, the force of the resin pipe contracting radially due to heat acts in a direction that presses the resin pipe against the connecting pipe, thus enabling a more secure connection between the resin pipe and the connecting pipe.

[0014] In the first configuration described above, the connecting pipe has a heating element on its outer circumference facing the inner circumference of the resin pipe, and the outer circumference of the connecting pipe and the inner circumference of the resin pipe are joined together by melting due to the heating of the heating element (third configuration).

[0015] This allows the pipe and the resin pipe to be joined to the connecting pipe by passing an electric current through the heating element of the connecting pipe. Therefore, the pipe and the resin pipe can be easily joined by the connecting pipe without being affected by the reduction in diameter of the resin pipe due to the heat generated by the heating element.

[0016] In any one of the first to third configurations described above, the pipe is a resin pipe (fourth configuration). This allows the resin pipes to be joined together by heat welding.

[0017] A connecting pipe according to one embodiment of the present invention is a connecting pipe for joining two pipes, each containing at least one resin pipe. The connecting pipe has an electric heating wire on the outer circumference of the end portion inserted into the at least one resin pipe, and is configured to have less radial deformation due to heat compared to a resin pipe formed by circumferential stretching and diameter expansion (fifth configuration).

[0018] This allows the resin pipe to be joined to the connecting pipe by inserting the connecting pipe into the resin pipe and passing an electric current through the heating element. Furthermore, even if the resin pipe to be joined is formed by stretching and expanding the diameter of at least the end portion including the joining portion in the circumferential direction, the connecting pipe can suppress the shrinking of the diameter of the resin pipe when heated.

[0019] Furthermore, the connecting pipe does not necessarily have to connect the two pipes simultaneously; they may be connected one at a time. Alternatively, one of the two pipes may be pre-connected to the connecting pipe. In this case, only the other pipe needs to be connected to the connecting pipe on-site, thus improving work efficiency.

[0020] In the fourth configuration described above, the outer diameter of the end of the connecting pipe inserted into the resin pipe is smaller than the outer diameter of the axial central portion of the connecting pipe (sixth configuration).

[0021] This prevents the connecting pipe from protruding significantly radially outward from the resin pipe when its end is inserted into the resin pipe. Moreover, the difference in diameter of the connecting pipe acts as a stopper when inserting it into the resin pipe. Therefore, it is easy to visually confirm that the connecting pipe is properly inserted into the resin pipe.

[0022] In the fifth or sixth configuration, the connecting pipe is made of a resin material (seventh configuration). By passing an electric current through the heating wire of the connecting pipe, the outer peripheral side of the connecting pipe made of a resin material and the inner peripheral side of the resin pipe facing it can be melted to join the connecting pipe and the resin pipe.

[0023] A resin pipe joining method according to an embodiment of the present invention is a resin pipe joining method for joining a resin pipe to a pipe. The resin pipe to be joined is formed by expanding the diameter by extending the end portion including at least the joining portion in the circumferential direction. The resin pipe joining method includes a support member arranging step of arranging a support member inside the end portion of the resin pipe so that the amount of radial deformation due to heat is less than that of the resin pipe, and a resin pipe joining step of joining the end portion of the resin pipe to the support member or the pipe by heating the end portion of the resin pipe while supporting the end portion of the resin pipe from the inside by the support member (first method).

[0024] When the resin pipe to be joined is a resin pipe formed by expanding the diameter by extending the end portion including at least the joining portion in the circumferential direction, when the resin pipe is heated and joined to the pipe, the joining portion of the resin pipe contracts in diameter due to heat.

[0025] On the other hand, as described above, by heating the end portion of the resin pipe while supporting the joining portion of the resin pipe from the inside by the support member and joining the end portion to the support member or the pipe, it is possible to suppress the reduction in diameter of the joining portion of the resin pipe. Therefore, a resin pipe formed by expanding the diameter by extending the end portion including at least the joining portion in the circumferential direction can be joined to another pipe by heating.

[0026] In the first method, in the resin tube joining step, the joining portion of the resin tube is configured such that the amount of radial deformation due to heat is less than that of the resin tube, and while being supported from the inside of the resin tube by a connecting tube functioning as the support member, the outer peripheral surface of the connecting tube and the inner peripheral surface of the resin tube are heated and melted to join the connecting tube and the resin tube (second method).

[0027] Thereby, a resin tube can be joined to a connecting tube functioning as a support member. Thus, the resin tube and the tube can be joined via the connecting tube.

[0028] In the first method, in the resin tube joining step, the ends of the tube and the resin tube are abutted against each other, and while the end of the resin tube is supported from the inside by the support member, the resin tube is heated to be joined (third method).

[0029] Thereby, when the ends of the tube and the resin tube are abutted and joined, by supporting from the inside the end of the resin tube formed by being stretched in the circumferential direction and expanded in diameter by the support member, it is possible to suppress the resin tube from shrinking in diameter due to heat.

[0030] Moreover, by supporting the end of the resin tube from the inside by the support member, it is possible to suppress the formation of beads during resin tube joining on the inner surface of the joining portion between the tube and the resin tube.

[0031] In the third method, the resin tube joining method further includes a support member removal step of removing the support member from the inside of the resin tube after the resin tube joining step (fourth method).

[0032] As a result, the support member that supports the end of the resin pipe to be joined from the inside can be removed from inside the resin pipe, so that the support member can be used only when joining the resin pipe. Therefore, when the resin pipe shrinks in diameter due to heat welding, the support member supports the resin pipe from the inside, and after the joining of the resin pipe is complete, the support member can be removed to prevent it from obstructing the fluid flow inside the joined resin pipe.

[0033] In the fourth method described above, the support member is configured to be switchable between a radial size that allows the resin pipe to be supported from the inside during the resin pipe joining process and a radial size that allows the support member to move inside the resin pipe during the support member removal process (fifth method).

[0034] As a result, in the resin pipe joining process, the resin pipe formed by extending and expanding the diameter of at least the end portion including the joining portion in the circumferential direction can be supported from the inside by the support member, while in the support member removal process, the support member can be moved inside the resin pipe and removed. Thus, the fourth method can be easily implemented.

[0035] A support device for joining resin pipes according to one embodiment of the present invention is a support device for joining resin pipes to a pipe. It is configured to reduce the amount of radial deformation due to heat compared to a resin pipe formed by circumferential stretching and expansion of its diameter, and has a support part that can switch between a radial size that can support the end portion including the joining part of the resin pipe from the inside and a radial size that can move inside the resin pipe, and a size switching drive unit that switches the radial size of the support part (8th configuration).

[0036] As a result, even if the resin pipe is formed by circumferentially extending and expanding the diameter of at least the end portion including the joint, the resin pipe can be joined to the pipe by heat welding while the resin pipe is supported from the inside by the support portion. After joining the resin pipe to the pipe, the support portion can be removed from inside the resin pipe by changing the radial size of the support portion to a radial size that allows it to move inside the pipe or the resin pipe using the size switching drive unit.

[0037] In the eighth configuration described above, the support device for joining resin pipes further includes a movable part that moves the support part inside the pipe or the resin pipe (ninth configuration).

[0038] This allows the support portion to be moved inside the pipe or resin pipe, positioning it inside the joint between the pipe and the resin pipe. After joining the pipe and the resin pipe by heat welding, the support portion can be removed from inside the pipe or resin pipe. [Effects of the Invention]

[0039] In a resin-joined pipe according to one embodiment of the present invention, the resin pipe joined to the pipe is formed by stretching and expanding the diameter of at least the end portion including the joining portion in the circumferential direction. The resin pipe is joined to the support member or the pipe by heating the end portion while the joining portion is supported from the inside by the support member.

[0040] This makes it possible to realize a configuration in which resin pipes, formed by extending and expanding the diameter of at least the end portion including the joint in the circumferential direction, can be joined in the axial direction. [Brief explanation of the drawing]

[0041] [Figure 1] Figure 1 is a cross-sectional view showing the schematic configuration of a resin jointing tube 1 according to Embodiment 1 of the present invention. [Figure 2]Figure 2 illustrates the process of joining pipes together using electrofusion with a fusion splicer. [Figure 3] Figure 3 is a flowchart showing the resin pipe joining method of Embodiment 1. [Figure 4] Figure 4 shows a schematic configuration of a resin-joined pipe joined by the resin pipe joining method according to Embodiment 2. [Figure 5] Figure 5 is a schematic diagram showing the resin pipe joining support device positioned inside a resin pipe. [Figure 6] Figure 6 is a longitudinal cross-sectional view showing the schematic configuration of the support section. [Figure 7] Figure 7 is a flowchart showing the resin pipe joining method according to Embodiment 2. [Figure 8] Figure 8 shows an example of joining a connecting pipe to two resin pipes, with the ends of the two resin pipes being supported from the inside by a cylindrical holding member. [Figure 9] Figure 9 shows how the connecting pipe is moved to the joining position while the ends of the two resin pipes are supported from the inside by a cylindrical holding member. [Figure 10] Figure 10 shows an example of joining two resin pipes, where the ends of the two resin pipes to be joined are supported from the inside by cylindrical holding members. [Figure 11] Figure 11 shows a state in which grooves are formed on the end faces of the joining ends of two resin pipes. [Figure 12] Figure 12 shows an example of joining two resin tubes to a holding member by heating them to reduce their diameter. [Figure 13] Figure 13 is a cross-sectional view showing an example in which a pair of protrusions are provided side by side in the circumferential direction on the outer circumferential surface of a main body that is shorter in the axial direction than the main body of Embodiment 1. [Figure 14] Figure 14 is a view of the configuration shown in Figure 13, seen from the direction of extension of the pair of protrusions. [Figure 15] Figure 15 is a cross-sectional view showing an example where the connecting pipe does not have a main body and only has a pair of resin pipe insertion parts. [Figure 16] Figure 16 is a view of the configuration shown in Figure 15, seen from the direction of extension of the pair of protrusions. [Modes for carrying out the invention]

[0042] The following describes each embodiment with reference to the drawings. In each drawing, the same parts are denoted by the same reference numerals, and the description of those parts will not be repeated. Note that the dimensions of the components in each drawing do not faithfully represent the dimensions of the actual components or the dimensional ratios of each component.

[0043] Furthermore, in the following explanation, the expressions "fix," "connect," and "attach" (hereinafter referred to as "fixing, etc.") include not only cases where components are directly fixed to each other, but also cases where they are fixed to each other via other components. In other words, in the following explanation, the expressions "fixing, etc." include both direct and indirect fixing of components to each other.

[0044] [Embodiment 1] (Resin joint pipe) Figure 1 is a cross-sectional view showing the schematic configuration of a resin jointed pipe 1 according to Embodiment 1 of the present invention. The cross-sectional view shown in Figure 1 is a cross-sectional view of the resin jointed pipe 1 cut in the axial direction. The resin jointed pipe 1 is constructed by joining two resin pipes P, P to a resin connecting pipe 10. One of the two resin pipes P, P corresponds to the resin pipe of the present invention, and the other resin pipe corresponds to the pipe.

[0045] The resin pipe P is a biaxially stretched pipe formed by stretching and expanding its diameter in the circumferential and axial directions. That is, the resin pipe P is formed by stretching it in the circumferential and axial directions while heated. The resin pipe P is a pipe made of polyolefin resin material, such as polyethylene pipe or polypropylene pipe. In addition to polyolefin-based materials, vinyl chloride resin material can also be used, but the material is not limited to this. In the case of a pipe made of vinyl chloride resin material that has been stretched and expanded in the circumferential direction, it is preferable to apply hot melt (adhesive) or the like to the outer surface of the connecting pipe 10 so that it can be bonded by the shrinkage force caused by heat.

[0046] (Connecting pipe) The connecting pipe 10 connects two resin pipes P, P. The connecting pipe 10 is an annular member made of resin. The connecting pipe 10 has a greater thickness than the two resin pipes P, P so that it is less susceptible to radial deformation due to heat than the two resin pipes P, P. Both axial ends of the connecting pipe 10 are configured to be insertable into the ends of the two resin pipes P, P. Specifically, the connecting pipe 10 has a main body 11 and a pair of resin pipe insertion parts 12, 12.

[0047] The main body 11 is tubular and located in the axial central portion of the connecting pipe 10. The pair of resin pipe insertion portions 12, 12 are tubular and located at both ends of the connecting pipe 10 in the axial direction. In other words, the main body 11 is located between the pair of resin pipe insertion portions 12, 12.

[0048] The outer diameter of the main body 11 is larger than the outer diameter of the pair of resin pipe insertion sections 12, 12. For example, the outer diameter of the main body 11 is the same size as the outer diameter of the resin pipes P, P into which the pair of resin pipe insertion sections 12, 12 are inserted. This allows the resin pipes P, P to be positioned relative to the connecting pipe 10 when they are inserted into the pair of resin pipe insertion sections 12, 12. The outer diameter of the main body 11 may be larger or smaller than the outer diameter of the resin pipes P, P into which the pair of resin pipe insertion sections 12, 12 are inserted.

[0049] Each of the pair of resin pipe insertion sections 12, 12 has a heating element 20 extending in the circumferential direction inside its outer surface. The heating element 20 is positioned inside the resin pipe insertion section 12 so as to follow the outer surface of the resin pipe insertion section 12. The heating elements 20 inside the pair of resin pipe insertion sections 12, 12 are electrically connected to each other. The ends of the electrically connected heating elements 20 are electrically connected to terminals 22, which will be described later, and which protrude radially outward from the main body 11.

[0050] The main body 11 has a pair of projections 21 that project radially from its outer circumferential surface, and a pair of terminals 22 arranged within the pair of projections 21. The pair of projections 21 are made of cylindrical resin and cover the pair of terminals 22. In this embodiment, the pair of projections 21 are arranged axially on the outer circumferential surface of the main body 11. Although not specifically shown, the pair of terminals 22 are exposed within the pair of projections 21. Each of the pair of terminals 22 is electrically connected to the end of the heating wire 20 which is electrically connected to each other.

[0051] With the above configuration, as shown in Figure 2, by inserting the output cable V of the fusion splicer W into the pair of protrusions 21 as described later, the output cable V is electrically connected to the pair of terminals 22, and current can be passed through the output cable V and the pair of terminals 22 to the heating wire 20. Therefore, the heating wire 20 melts the outer surfaces of the pair of resin pipe insertion parts 12, 12 which are located inside the outer surface side, and also melts the inner surfaces of the resin pipes P, P into which the pair of resin pipe insertion parts 12, 12 are inserted, thereby joining the connecting pipe 10 and the resin pipes P, P. The configuration of the fusion splicer W is the same as the conventional configuration. Therefore, a detailed explanation of the configuration of the fusion splicer W is omitted.

[0052] Here, the resin pipes P,P are formed by being stretched and expanded in the circumferential and axial directions while heated, as described above. Therefore, as mentioned above, when the resin pipes P,P are heated by the heating element 20 of the connecting pipe 10, they contract radially.

[0053] If the connecting pipe has a configuration in which a resin pipe is inserted inside, as described above, when the resin pipe shrinks radially due to heat, a gap will be created between the resin pipes P,P and the resin pipe insertion portions 12,12 of the connecting pipe 10. Therefore, it may not be possible to melt and join the resin pipes P,P and the resin pipe insertion portions 12,12.

[0054] In contrast, in this embodiment, the resin pipe insertion portions 12, 12 of the connecting pipe 10 are inserted into the ends of the resin pipes P, P. Therefore, as described above, when the resin pipes P, P contract radially, the inner circumferential surfaces of the resin pipes P, P are pressed against the outer circumferential surfaces of the resin pipe insertion portions 12, 12 of the connecting pipe 10, and come into close contact with the outer circumferential surfaces of the resin pipe insertion portions 12, 12 of the connecting pipe 10. Thus, the inner circumferential surfaces of the resin pipes P, P and the outer circumferential surfaces of the resin pipe insertion portions 12, 12 of the connecting pipe 10 can be melted and joined more firmly. Reference numeral 30 in Figure 1 indicates the joint portion where the connecting pipe 10 and the resin pipes P, P are joined.

[0055] Thus, the connecting pipe 10 has resin pipe insertion portions 12, 12 located inside the resin pipes P, P, and can support the heated and shrunk resin pipes P, P from within. Therefore, the connecting pipe 10 functions as a support member of the present invention.

[0056] The resin jointed pipe 1 according to this embodiment is a resin jointed pipe in which two resin pipes P, P are joined by heat welding. At least one of the two joined resin pipes P, P is formed by extending and expanding the diameter of at least the end including the joint portion 30 in the circumferential direction. The two resin pipes P, P are joined by heating the connecting pipe 10 and the ends of the two resin pipes P, P while the joint portion 30 of at least one of the resin pipes is supported from the inside by the connecting pipe 10.

[0057] If at least one of the two resin pipes P, P to be joined is a resin pipe formed by stretching and expanding the diameter of at least the end including the joining portion 30 in the circumferential direction, then when the two resin pipes P, P are joined by heat welding, the joining portion 30 of at least one of the pipes will shrink in diameter due to the heat.

[0058] In contrast, as described above, by joining two resin pipes P, P while supporting the joint portion 30 of at least one of the resin pipes from the inside with the connecting pipe 10, it is possible to suppress the reduction in diameter of the joint portion 30 of at least one of the resin pipes. Therefore, a resin pipe formed by expanding the diameter by circumferential stretching of at least the end including the joint portion 30 can be joined to another resin pipe by heat welding.

[0059] Furthermore, in this embodiment, the resin jointing pipe 1 is configured to undergo less radial deformation due to heat compared to the two resin pipes P, P, and functions as a support member by being located inside the two resin pipes P, P and supporting the joint portion 30 between the two resin pipes P, P from inside the two resin pipes P, P, and has a connecting pipe 10 whose outer surface is joined to the inner surface of the two resin pipes P, P by heating.

[0060] As a result, the connecting pipe 10 allows two resin pipes P, P to be joined together, and the joining portion 30 of the two resin pipes P, P is supported from the inside of the two resin pipes P, P, preventing the joining portion 30 of the two resin pipes P, P from shrinking in diameter, which is formed by the circumferential extension and expansion of at least the end including the joining portion 30. Therefore, one resin pipe P can be joined to another resin pipe P via the connecting pipe 10.

[0061] Furthermore, the force of the resin pipe P contracting radially due to heat acts to press the resin pipe P against the connecting pipe 10, thus enabling more reliable heat welding of the resin pipe P and the connecting pipe 10.

[0062] In this embodiment, the connecting pipe 10 joins the two resin pipes P, P by heat welding. The connecting pipe 10 has heating wires 20 on its outer circumference, which are opposite the inner circumferences of the two resin pipes P, P. The outer circumference of the connecting pipe 10 is joined to the inner circumferences of the two resin pipes P, P by heating with the heating wires 20.

[0063] This allows the two resin pipes P,P to be joined to the connecting pipe 10 by passing an electric current through the heating element 20 of the connecting pipe 10. Therefore, the two resin pipes P,P can be easily joined by the connecting pipe 10 without being affected by the reduction in diameter of the two resin pipes P,P due to the heat generated by the heating element 20.

[0064] Furthermore, in this embodiment, the connecting pipe 10 has a heating element on the outer circumference of at least one of the ends that are inserted into the two resin pipes. The connecting pipe 10 is configured to undergo less radial deformation due to heat compared to the two resin pipes P, P which are formed by being stretched and expanded in the circumferential direction.

[0065] This allows the two resin pipes P, P to be joined to the connecting pipe 10 by inserting the connecting pipe 10 into the two resin pipes P, P and passing an electric current through the heating wire 20. Moreover, even if at least one of the two resin pipes P, P to be joined is a resin pipe formed by extending and expanding the diameter of at least the end including the joining portion 30 in the circumferential direction, the connecting pipe 10 can suppress the reduction in diameter of the resin pipe P during heat welding.

[0066] Furthermore, the connecting pipe 10 does not necessarily have to weld the two resin pipes P, P simultaneously; they may be joined one at a time. Alternatively, one of the two resin pipes P, P may be heat-welded to the connecting pipe 10 beforehand. In this case, only the other resin pipe P needs to be heat-welded to the connecting pipe 10 on-site, thus improving work efficiency.

[0067] Furthermore, in this embodiment, the outer diameter of the ends of the connecting pipe 10 that are inserted into the two resin pipes P, P is smaller than the outer diameter of the central portion in the axial direction.

[0068] This prevents the connecting pipe 10 from protruding significantly radially outward from the two resin pipes P, P when its end is inserted into each of them. Moreover, the difference in diameter of the connecting pipe 10 acts as a stopper when inserting it into the two resin pipes P, P. Therefore, it is easy to visually confirm that the connecting pipe 10 is properly inserted into the two resin pipes P, P.

[0069] Furthermore, in this embodiment, the connecting pipe 10 is made of a resin material. By passing an electric current through the heating element 20 of the connecting pipe 10, the outer circumference of the connecting pipe 10, which is made of resin material, and the inner circumferences of the two opposing resin pipes P, P can be melted, thereby joining the connecting pipe 10 to the two resin pipes P, P. Thus, the two resin pipes P, P can be easily joined by the connecting pipe 10.

[0070] (Resin pipe joining method) Next, a method for joining resin pipes P, P to the connecting pipe 10 in order to obtain the resin jointed pipe described above will be explained using Figure 3. Figure 3 is a flowchart of the resin pipe joining method of this embodiment.

[0071] When the flow shown in Figure 3 starts (START), first in step SA1, the resin pipe insertion sections 12, 12 located at both axial ends of the connecting pipe 10 are inserted into the ends of the two resin pipes P, P, respectively.

[0072] In the following step SA2, the output cable V of the fusion splicer W is electrically connected to the pair of terminals 22 of the connecting pipe 10. Then, in step SA3, current is passed from the output cable V of the fusion splicer W to the pair of terminals 22, 22 of the connecting pipe 10. As a result, the heating element 20 of the connecting pipe 10 is heated, melting the resin pipe insertion parts 12, 12 of the connecting pipe 10 and the two resin pipes P, P, and allowing them to be joined.

[0073] In this process, the two resin tubes P,P, formed by being stretched and expanded in the circumferential and axial directions while being heated, contract radially due to the heating of the heating element 20 of the connecting tube 10, pressing their inner surfaces against the outer surfaces of the resin tube insertion portions 12,12 of the connecting tube 10. This allows the two resin tubes P,P and the resin tube insertion portions 12,12 of the connecting tube 10 to be melted and joined in a more tightly fitted state.

[0074] Next, the power to the fusion splicer W is turned off (step SA4), and the output cable V of the fusion splicer W is disconnected from the pair of terminals 22, 22 of the connecting pipe 10 (step SA5). This flow is then completed (END).

[0075] Here, step SA1 corresponds to the support member placement process, and step SA3 corresponds to the resin pipe joining process.

[0076] The resin pipe joining method of this embodiment is a resin pipe joining method that joins two resin pipes P, P by heat welding. At least one of the two resin pipes P, P to be joined is formed by stretching and expanding the diameter of at least the end including the joining portion 30 in the circumferential direction. The resin pipe joining method includes a support member placement step SA1 in which a connecting pipe 10 (support member) is placed inside the end of at least one of the resin pipes, configured to undergo less radial deformation due to heat compared to the two resin pipes P, P, and a resin pipe joining step SA3 in which the two resin pipes P, P and the connecting pipe 10 are joined by heating them while the end of at least one of the resin pipes is supported from the inside by the connecting pipe 10.

[0077] If at least one of the two resin pipes P, P to be joined is a resin pipe formed by stretching and expanding the diameter of at least the end including the joining portion 30 in the circumferential direction, then when the two resin pipes P, P are joined by heat welding, the joining portion 30 of at least one of the pipes will shrink in diameter due to the heat.

[0078] In contrast, as described above, by joining two resin pipes P, P while supporting the joint portion 30 of at least one of the resin pipes from the inside with the connecting pipe 10, it is possible to suppress the reduction in diameter of the joint portion 30 of at least one of the resin pipes. Therefore, a resin pipe formed by expanding the diameter by circumferential stretching of at least the end including the joint portion 30 can be joined to another resin pipe by heat welding.

[0079] [Embodiment 2] Figure 4 shows a schematic configuration of a resin jointed pipe 100 joined by the resin pipe joining method according to Embodiment 2. The resin jointed pipe 100 is formed by joining the ends of resin pipes P, P in a butted position in the axial direction. The joint portion 130 in the resin jointed pipe 100 is also joined by melting the resin and heat welding it. Specifically, one end of each resin pipe P, P in the axial direction is heated to melt the resin, and then the end faces are butted together in the axial direction to join the resin pipes P, P.

[0080] As described above, when joining two resin pipes P,P together, the resin pipe joining support device 150, as shown in Figure 5, supports the inner surface of the joining portion 130 of the two resin pipes P,P. Figure 5 is a schematic diagram showing the resin pipe joining support device 150 positioned inside the resin pipes P,P. By supporting the inner surface of the joining portion 130 of the two resin pipes P,P with the resin pipe joining support device 150, it is possible to suppress the radial shrinkage of the ends of the resin pipes P,P due to heating. Therefore, the resin pipes P,P can be joined by heat welding without shrinking in diameter. Accordingly, the resin pipe joining support device 150 of this embodiment functions as a support member of the present invention.

[0081] The resin pipe joining support device 150 is configured to be movable axially within the resin pipes P, P and to support the inner surface of the joining portion 130 of the two resin pipes P, P. Specifically, the resin pipe joining support device 150 includes a motor 151 (size switching drive unit), a support unit 152, and a moving unit 156.

[0082] Figure 6 is a longitudinal cross-sectional view showing the schematic configuration of the support portion 152. The support portion 152 is a disc-shaped member that is configured to expand radially by the rotational driving force of the motor 151. More specifically, as shown in Figure 6, the support portion 152 has a pair of frustoconical disc portions 153, 153, an annular belt portion 154, and a threaded portion 155.

[0083] Each of the pair of disc portions 153, 153 has a slanted surface 153a on its outer circumference. The pair of disc portions 153, 153 are arranged so that their slanted surfaces 153a face each other and overlap in the thickness direction. A threaded portion 155 passes through and screws into the pair of disc portions 153, 153. One of the pair of disc portions 153, 153 is configured to move closer to the other disc portion 153 by the rotation of the threaded portion 155. In other words, the pair of disc portions 153, 153 are relatively movable in the axial direction of the threaded portion 155 by the rotation of the threaded portion 155. The threaded portion 155 is rotated by a motor 151.

[0084] The belt portion 154 is located on the inclined surfaces 153a, 153a of the pair of disc portions 153, 153. The belt portion 154 is a member that is circumferentially expandable (for example, a resin member such as rubber). When the pair of disc portions 153, 153 are separated in the axial direction of the screw portion 155, the belt portion 154 is located between the inclined surfaces 153a, 153a of the pair of disc portions 153, 153. On the other hand, when the pair of disc portions 153, 153 are close together, the belt portion 154 is radially expanded by the inclined surfaces 153a, 153a of the pair of disc portions 153, 153, and is located radially outward from the pair of disc portions 153, 153.

[0085] With the above configuration, the belt portion 154 can be switched between a position radially inward and a position radially outward relative to the pair of disc portions 153, 153. The resin pipe joining support device 150 is configured such that when the belt portion 154 is located radially outward relative to the pair of disc portions 153, 153, the belt portion 154 contacts and supports the inner circumferential surface of the resin pipes P, P. On the other hand, when the belt portion 154 is located radially inward relative to the pair of disc portions 153, 153, the resin pipe joining support device 150 is configured so that the belt portion 154 does not contact the inner surface of the resin pipes P, P.

[0086] As shown in Figure 5, the movable part 156 is configured to allow the resin pipe joining support device 150 to move axially within the resin pipes P, P. The movable part 156 has a base 157 on which the motor 151 and support part 152 are mounted, and a plurality of wheels 158 that can move the base 157. This allows the resin pipe joining support device 150 to be moved axially within the resin pipes P, P, and the support part 152 of the resin pipe joining support device 150 to be easily positioned on the inner circumference side of the joining portion 130 of the resin pipes P, P.

[0087] The resin pipe joining support device 150 according to this embodiment is used when joining two resin pipes P, P by heat welding. It is configured to reduce the amount of radial deformation due to heat compared to a resin pipe formed by circumferential stretching and diameter expansion, and includes a support part 152 that can switch between a radial size capable of supporting at least one of the two resin pipes P, P from the inside, which is formed by circumferential stretching and diameter expansion of at least one of the ends including the joining portion 130, and a radial size capable of moving the inside of at least one of the two resin pipes P, P, and a motor 151 as a size switching drive unit for switching the radial size of the support part 152.

[0088] As a result, even if at least one of the two resin pipes P,P is formed by circumferentially extending and expanding the diameter of at least one end including the joint portion 130, the two resin pipes P,P can be joined by heat welding while the at least one resin pipe is supported from the inside by the support portion 152. After joining the two resin pipes P,P, the motor 151 changes the radial size of the support portion 152 to a radial size that allows movement inside at least one of the two resin pipes P,P, thereby allowing the support portion 152 to be removed from inside the two resin pipes P,P.

[0089] Furthermore, in this embodiment, the resin pipe joining support device 150 further includes a moving part 156 that moves the support part 152 inside at least one of the two resin pipes P, P. This allows the support part 152 to be moved inside at least one of the two resin pipes P, P, and positioned inside the joining portion 130 of the two resin pipes P, P. After joining the two resin pipes P, P by heat welding, the support part 152 can be removed from inside the two resin pipes P, P.

[0090] (Resin pipe joining method) Figure 7 is a flowchart showing the resin pipe joining method according to Embodiment 2. The resin pipe joining method of Embodiment 2 will be described below with reference to Figure 7.

[0091] When the flow shown in Figure 7 starts (START), first in step SB1, the moving part 156 moves the resin pipe joining support device 150 axially within the two resin pipes P, P, positioning the resin pipe joining support device 150 near the joining position of the two resin pipes P, P.

[0092] In the following step SB2, the ends of the two resin pipes P, P to be joined are heated. At this time, the ends of the two resin pipes P, P are heated by a heating device such as a heater. After that, the two resin pipes P, P are joined together (step SB3).

[0093] Subsequently, in step SB4, the resin pipe joining support device 150 is moved to the joining position. In the following step SB5, the motor 151 is driven to rotate the threaded portion 155 of the support portion 152. This brings the pair of disc portions 153, 153 closer together and expands the diameter of the belt portion 154. The belt portion 154 of the support portion 152 is brought into contact with the joining portion 130 of the two resin pipes P, P, and the support portion 152 supports the joining portion 130 of the two resin pipes P, P (step SB6).

[0094] As described above, the support portion 152 of the resin pipe joining support device 150 supports the joining portion 130 of the two resin pipes P,P, thereby suppressing the reduction in diameter of the two resin pipes P,P due to heating. Therefore, the two resin pipes P,P can be joined while suppressing the reduction in diameter. Moreover, since the belt portion 154 of the support portion 152 contacts the inside of the joining portion 130 of the two resin pipes P,P, it is possible to suppress the leakage of molten resin from the joining portion 130 into the inside. Therefore, the fluidity of the fluid at the joining portion 130 of the two resin pipes P,P can be improved.

[0095] As described above, after joining the two resin pipes P, P, in step SB7, the motor 151 of the resin pipe joining support device 150 is driven to rotate the threaded portion 155 of the support portion 152. This separates the pair of disc portions 153, 153 and reduces the diameter of the belt portion 154. Thus, the belt portion 154 can be separated radially inward from the end portion including the joining portion 130 of the two resin pipes P, P.

[0096] Subsequently, the moving part 156 moves the resin pipe joining support device 150 from inside the two resin pipes P, P to the outside (step SB8). Then, this flow is completed (END).

[0097] Here, step SB1 corresponds to the support member placement process, steps SB2 and SB6 correspond to the resin pipe joining process, and steps SB7 and SB8 correspond to the support member removal process.

[0098] The resin pipe joining method according to this embodiment is a method of joining two resin pipes P, P by heat welding. At least one of the two resin pipes P, P to be joined is formed by stretching and expanding the diameter of at least one end including the joining portion 130 in the circumferential direction. The resin pipe joining method includes a support member placement step SB1 in which a support member is placed inside the end of the at least one resin pipe, configured to undergo less radial deformation due to heat compared to the two resin pipes P, P, and resin pipe joining steps SB3 to SB5 in which the two resin pipes P, P are joined by heating them while the end of the at least one resin pipe is supported from the inside by a resin pipe joining support device 150.

[0099] If at least one of the two resin pipes P, P to be joined is a resin pipe formed by stretching and expanding the diameter of at least the end including the joining portion in the circumferential direction, then when the two resin pipes P, P are joined by heat welding, the end including the joining portion 130 of at least one of the pipes will shrink in diameter due to the heat.

[0100] In contrast, as described above, by joining two resin pipes P, P while supporting the end of at least one of the resin pipes, including the joint portion 130, from the inside with a support member, it is possible to suppress the reduction in diameter of the end of at least one of the resin pipes, including the joint portion 130. Therefore, a resin pipe formed by the circumferential stretching and expansion of at least the end including the joint portion 130 can be joined to another resin pipe by heat welding.

[0101] Furthermore, in resin pipe joining processes SB3 to SB5, the ends of the two resin pipes P, P are butted together, and with at least one end of the resin pipe supported from the inside by the resin pipe joining support device 150, the two resin pipes P, P are joined by heating.

[0102] As a result, when joining the ends of two resin pipes P,P together, the resin pipe joining support device 150 supports the ends of the two resin pipes P,P from the inside, thereby suppressing the shrinking of the diameter of one of the two resin pipes P,P, which is formed by being stretched and expanded in the circumferential direction, due to heat.

[0103] Furthermore, by supporting the ends of the two resin pipes from the inside with the resin pipe joining support device 150, it is possible to suppress the formation of a bead on the inner surface of the joining portion 130 of the two resin pipes P, P during resin pipe joining.

[0104] Furthermore, the resin pipe joining method further includes support member removal steps SB6 and SB7, after the resin pipe joining steps SB3 to SB5, in which the resin pipe joining support device 150 is removed from inside at least one of the resin pipes.

[0105] This allows the resin pipe joining support device 150, which supports the ends of the resin pipes to be joined from the inside, to be removed from inside the resin pipes. Therefore, the resin pipe joining support device 150 can be used only when joining resin pipes together. Thus, when the resin pipe shrinks in diameter due to heat welding, the resin pipe joining support device 150 supports the resin pipe from the inside, and after the joining of the two resin pipes P, P is completed, the resin pipe joining support device 150 can be removed to prevent it from obstructing the fluid flow inside the joined resin pipes.

[0106] Furthermore, the resin pipe joining support device 150 is configured to be switchable between a radial size that allows for the support of at least one of the resin pipes from the inside during the resin pipe joining processes SB3 to SB5, and a radial size that allows for the movement of at least one of the two resin pipes P, P from the inside during the support member removal processes SB6 and SB7.

[0107] As a result, in resin pipe joining processes SB3 to SB5, at least one resin pipe formed by circumferentially extending and expanding the diameter of at least the end including the joining portion 130 can be supported from the inside by the resin pipe joining support device 150, while in support member removal processes SB6 and SB7, the resin pipe joining support device 150 can be moved inside at least one of the two resin pipes P, P to remove it.

[0108] (Other embodiments) Although embodiments of the present invention have been described above, the embodiments described above are merely examples for carrying out the present invention. Therefore, the invention is not limited to the embodiments described above, and it is possible to carry out the invention by appropriately modifying the embodiments described above without departing from the spirit of the invention.

[0109] In each of the embodiments described above, both resin pipes P, P are biaxially stretched pipes formed by stretching in the circumferential and axial directions. However, only one of the resin pipes may be a biaxially stretched pipe formed by stretching in the circumferential and axial directions. In this case, the configuration of each embodiment may be applied only to the portion where the biaxially stretched resin pipes are joined. Furthermore, only the end portion including the joining portion of the resin pipes may be formed by stretching in the circumferential and axial directions, or the entire resin pipe may be formed by stretching in the circumferential and axial directions. Also, only one of the two pipes to be joined may be a resin pipe. In this case, the other pipe may be made of a material other than resin, such as a metal pipe. In this case, the other pipe corresponds to the pipe of the present invention.

[0110] In the above embodiment 1, the connecting pipe 10 has a heating element 20 on the outer circumference of the resin pipe insertion portion 12. However, the connecting pipe does not have to have a heating element. The connecting pipe and the resin pipe may be heated and heat-welded together by means other than a heating element.

[0111] In the above embodiment 1, the connecting pipe 10 has a pipe thickness greater than the pipe thickness of the two resin pipes P, P so that the amount of radial deformation due to heat is less than that of the two resin pipes P, P. However, the connecting pipe does not have to have a pipe thickness greater than the pipe thickness of the two resin pipes P, P as long as it has a thickness that can suppress the reduction in diameter of the two resin pipes P, P. That is, the connecting pipe may have a pipe thickness equal to or smaller than the pipe thickness of the two resin pipes P, P as long as it can suppress the reduction in diameter of the two resin pipes P, P. Furthermore, the connecting pipe may be made of a material that undergoes less radial deformation due to heat than the two resin pipes. At least a part of the connecting pipe may be made of a material other than resin, such as a metal material.

[0112] In the above embodiment 1, a groove extending in the circumferential direction may be provided on the outer circumference of the resin pipe insertion portion 12 of the connecting pipe 10, and an annular sealing member may be placed in the groove. This allows the sealing member to seal the space between the outer circumference of the resin pipe insertion portion 12 of the connecting pipe 10 and the inner circumference of the resin pipes P, P into which the resin pipe insertion portion 12 is inserted.

[0113] In the above embodiment 2, the resin pipe joining support device 150 has a support portion 152 that is configured to expand radially by the rotational driving force of the motor 151. However, the resin pipe joining support device may have any configuration as long as it is capable of supporting the joint portion of the two resin pipes from the inside. For example, the resin pipe joining support device may have an expansion member that expands with gas. In this case, the expansion member supports the joint portion of the two resin pipes from the inside. In this case, a pump or the like that supplies gas to the expansion member corresponds to the size switching drive unit.

[0114] In the above embodiment 2, the resin pipe joining support device 150 may have an imaging unit capable of imaging the inside of the resin pipes P, P.

[0115] In the above embodiment 1, the connecting pipe 10 is placed inside the ends of the two resin pipes P, P, and the outer surface of the resin pipe insertion portion 12, 12 of the connecting pipe 10 and the inner surface of the ends of the two resin pipes P, P are melted by heating the electric heating element 20 of the connecting pipe 10 to join them. However, the connecting pipe may be placed outside the ends of the two resin pipes P, P, and a cylindrical holding member 250 may be placed inside the ends of the two resin pipes P, P, and the inner surface of the connecting pipe and the outer surface of the ends of the two resin pipes P, P may be melted by heating the electric heating element of the connecting pipe to join them.

[0116] Figure 8 shows an example of joining two resin pipes P, P with a connecting pipe 210 while the joining ends of the two resin pipes P, P are supported from the inside by a cylindrical holding member 250 (support member). This prevents the ends of the two resin pipes P, P from shrinking in diameter when the heating element 20 of the connecting pipe 210, positioned outside the ends of the two resin pipes P, P, is heated and melts the inner surface of the connecting pipe 210 and the outer surface of the ends of the two resin pipes P, P. In Figure 8, reference numeral 230 denotes the joining portion, and the same reference numerals are used for components similar to those in Embodiment 1, and their explanation is omitted.

[0117] As shown in Figure 8, when joining the connecting pipe 210 and the two resin pipes P, P using the retaining member 250, one of the resin pipes P is inserted into the connecting pipe 210 beforehand, the retaining member 250 is inserted into the end where the two resin pipes P, P are joined, and then, as shown in Figure 9, the connecting pipe 210 is moved to the joining position for the two resin pipes P, P.

[0118] Furthermore, at least the joint portion of the resin pipes P,P is formed by stretching in the circumferential direction. Therefore, as shown in Figure 12, a cylindrical retaining member 450 may be placed inside the ends of the two resin pipes P,P, and the portion of the outer surface of the two resin pipes P,P that overlaps radially with respect to the retaining member 450 (supporting member) may be heated, for example, with a sheet heater, to reduce the diameter of the two resin pipes P,P as shown by the dashed line and join them tightly to the retaining member 450. This allows the two resin pipes P,P and the retaining member 450 to be joined in a way that provides watertightness.

[0119] The shape of the outer surface of the retaining member 450 is not particularly limited, but it is preferable to provide multiple circumferentially extending protrusions on the outer surface of the joint portion of the retaining member 450 in order to prevent the resin pipes P,P from coming out of the joint portion of the retaining member 450. It is even more preferable to place an O-ring between the retaining member 450 and the resin pipes P,P. This improves the watertightness against bending of the resin pipes P,P. These configurations can be appropriately selected depending on the properties of the two resin pipes P,P and their applications.

[0120] In the above embodiment 2, when joining the resin pipes P, P together, the resin pipe joining support device 150 supports the inner surface of the joining portion 130 of the two resin pipes P, P. However, the joining ends of the two resin pipes P, P may be supported from the inside by a cylindrical holding member (support member).

[0121] Figure 10 shows an example of joining two resin pipes P, P with the ends to be joined supported from the inside by cylindrical holding members 350, 350 (support members). This suppresses the reduction in diameter of the ends when the ends of the two resin pipes P, P are joined by butting them together while they are molten. In this case, in order to suppress the formation of a bead on the inner surface of the joining portion 330 of the resin pipes P, P, it is preferable to provide a groove 331 on the inner circumference of the axial end face to be joined in the resin pipes P, P, as shown in Figure 11. After forming the groove 331 on the axial end face of the resin pipes P, P as shown in Figure 11, the holding members 350, 350 are inserted into the ends of the resin pipes P, P, respectively, and the end faces of the resin pipes P, P are heated and melted and butted together in the axial direction to join the ends of the resin pipes P, P as shown in Figure 10.

[0122] In the above embodiment 1, the pair of protrusions 21 of the connecting pipe 10 are arranged axially on the outer circumferential surface of the main body 11. However, the main body may be narrowed axially, and the pair of protrusions may be arranged circumferentially on the outer circumferential surface of the main body.

[0123] Figure 13 is a cross-sectional view showing an example in which a pair of protrusions 521 are provided circumferentially on the outer circumferential surface of a main body portion 511 that is shorter in the axial direction than the main body portion 11 of Embodiment 1. Figure 14 is a view of the configuration shown in Figure 13 from the direction of extension of the pair of protrusions 521. With the configurations shown in Figures 13 and 14, the axial length of the connecting pipe 510 can be shortened compared to the configuration of Embodiment 1. In Figures 13 and 14, reference numeral 512 denotes a resin pipe insertion portion, and reference numeral 522 denotes a terminal.

[0124] Figure 15 is a cross-sectional view showing an example in which the connecting pipe 610 has only a pair of resin pipe insertion portions 622 and no main body. The pair of protrusions 621 are provided so as to extend radially outward at the connection portion of the pair of resin pipe insertion portions 622. Figure 16 is a view of the configuration shown in Figure 15 from the direction of extension of the pair of protrusions 621. With the configurations shown in Figures 15 and 16, the axial length of the connecting pipe 610 can be made even shorter compared to the configuration of Embodiment 1 and the configuration shown in Figure 13. In Figures 15 and 16, reference numeral 622 denotes a terminal. [Industrial applicability]

[0125] The present invention can be used for a connecting pipe that joins two resin pipes by heat welding, a resin jointed pipe obtained thereby, and a resin pipe joining method. [Explanation of symbols]

[0126] 1, 100, 300 resin jointed pipe 10, 510, 610 connecting pipes (support members) 11, 511 Main body 12, 512, 612 Resin pipe insertion section 20 heating wire 21, 521, 621 protrusion Terminals 22, 522, 622 30, 130, 330 joint part 231 Groove 150 Support device (support member) for joining resin pipes 151 Motor (size switching drive unit) 152 Support part 153 Disc section 153a Slope 154 Belt section 155 Threaded section 156 Mobile section 210 connecting pipe 331 Groove 250, 350, 450 Holding members (support members) P resin pipe V output cable W Fusion Splicer

Claims

1. A resin jointed pipe in which a resin pipe is joined to a pipe, The joined resin tube is formed by extending and expanding the diameter of at least the end portion including the joining portion in the circumferential direction, The resin pipe is joined to the support member or the pipe by heating its end while the joint portion is supported from the inside by the support member. Resin jointed pipe.

2. In the resin jointed pipe according to claim 1, The present invention further comprises a connecting pipe which is configured to reduce the amount of radial deformation due to heat compared to the aforementioned resin pipe, and which functions as the support member by being located inside the end of the aforementioned resin pipe and supporting the aforementioned resin pipe from the inside, and whose outer surface is joined to the inner surface of the aforementioned resin pipe by heating. Resin jointed pipe.

3. In the resin jointed pipe according to claim 2, The connecting pipe has a heating element on its outer circumference facing the inner circumference of the resin pipe. The outer surface of the connecting pipe and the inner surface of the resin pipe are joined together by melting them with the heating of the electric heating element. Resin jointed pipe.

4. In the resin joint pipe according to any one of claims 1 to 3, The aforementioned pipe is a resin pipe. Resin jointed pipe.

5. A connecting pipe for joining two pipes, each containing at least one resin pipe, The outer circumference of the end portion inserted into the aforementioned at least one resin tube has a heating element, It is configured to have less radial deformation due to heat compared to a resin tube formed by circumferential stretching and expansion. Connecting pipe.

6. In the connecting pipe according to claim 5, The outer diameter of the end portion inserted into the resin tube is smaller than the outer diameter of the central portion in the axial direction. Connecting pipe.

7. In the connecting pipe according to claim 5 or 6, The connecting pipe is made of a resin material. Connecting pipe.

8. A method for joining resin pipes to a pipe, The resin pipe to be joined is formed by extending and expanding the diameter of at least the end portion including the joining portion in the circumferential direction, The resin pipe joining method described above is: A support member placement step involves placing a support member inside the end of the resin pipe, configured such that the amount of radial deformation due to heat is less than that of the resin pipe. A resin pipe joining step in which the end of the resin pipe is joined to the support member or the pipe by heating the end of the resin pipe while the end of the resin pipe is supported from the inside by the support member, Having, Resin pipe joining method.

9. In the resin pipe joining method according to claim 8, In the resin pipe joining process, The joint portion of the resin pipe is configured such that the amount of radial deformation due to heat is less than that of the resin pipe, and is supported from the inside of the resin pipe by the connecting pipe which functions as a support member. The connecting pipe and the resin pipe are joined by heating and melting the outer surface of the connecting pipe and the inner surface of the resin pipe. Resin pipe joining method.

10. In the resin pipe joining method according to claim 8, In the resin pipe joining process, the pipe and the ends of the resin pipes are butted together, and the ends of the resin pipes are supported from the inside by the support members, and the resin pipes are joined by heating them. Resin pipe joining method.

11. In the resin pipe joining method according to claim 10, The process further includes a support member removal step, in which the support member is removed from the inside of the resin pipe after the resin pipe joining step. Resin pipe joining method.

12. In the resin pipe joining method according to claim 11, The support member is configured to be switchable between a radial size that allows the resin pipe to be supported from the inside during the resin pipe joining process and a radial size that allows it to move inside the resin pipe during the support member removal process. Resin pipe joining method.

13. In the resin pipe joining method according to any one of claims 8 to 12, The aforementioned pipe is a resin pipe. Resin pipe joining method.

14. A support device for joining resin pipes, used when joining resin pipes to a pipe, The support portion is configured to reduce radial deformation due to heat compared to a resin pipe formed by circumferential stretching and expansion, and is configured to be switchable between a radial size capable of supporting the end portion including the joint of the resin pipe from the inside, and a radial size capable of moving inside the pipe or the resin pipe. A size switching drive unit for switching the radial size of the support portion, Having, Support device for resin pipe joining.

15. In the support device for joining resin pipes according to claim 14, The support portion further has a movable portion that moves inside the pipe or the resin pipe. Support device for resin pipe joining.

Images