Piping connection device

Abstract

To reduce a risk of damage in the vicinity of a connection end of a synthetic resin pipe.SOLUTION: A piping connection device 10 comprises: a seal ring 20; a pair of housings 22 and 22; fastening means 24; and a pair of joints 26 and 26. The paired housings 22 and 22 hold an outer peripheral surface of the seal ring 20 therebetween. The fastening means 24 fastens a gap between ends of the housings 22 and 22. The joint 26 includes a cylindrical body for fusion and a protective body. The cylindrical body for fusion is fused to an end of a synthetic resin pipe 200. The protective body is fitted to an outer periphery of the cylindrical body for fusion. The protective body is disposed to cover a part estimated to be in contact.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a pipe connection device. [Background technology]

[0002] Patent Document 1 discloses an electric fusion pipe joint. This electric fusion pipe joint includes a pipe joint body made of thermoplastic resin, a heating wire, and an impedance element. The heating wire is provided inside or on the inner surface of the pipe joint body. The impedance elements are connected to both ends of the heating wire.

[0003] Patent Document 2 discloses a joint. This joint includes two opposing flanges, a gasket, and a flange. A synthetic resin pipe is connected to the two flanges in a one-to-one ratio. The gasket is sandwiched between the two flanges. The flange tightens the two flanges.

[0004] Patent Document 3 discloses a pipe connection device. This pipe connection device connects water supply and sewerage pipes and the like that are installed in a building or the like. This pipe connection device includes a seal ring, a housing-type pipe joint, a locking ridge, and a fastening means. The seal ring seals the outer peripheral surfaces of the connection ends of the pipes to be connected to each other. The housing-type pipe joint is formed by dividing an annular body in the circumferential direction. The housing-type pipe joint is composed of a plurality of housings. The outer peripheral surface of the seal ring is sandwiched between the plurality of housings. The locking ridge is provided in an annular shape and protrudes from the outer peripheral surface of the connection end of the pipe. The locking ridge engages with the inner peripheral opening edge of the housing from the inside, thereby preventing the pipe from coming out of the housing. The fastening means presses the seal ring against the outer peripheral surface of the connection end of the pipe by fastening the ends of the housing together. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 4-166325 [Patent Document 2] CD-ROM of Japanese Utility Model Application No. 1-116068 (Japanese Utility Model Application No. 3-55986) [Patent Document 3] JP 2020-16246 A Summary of the Invention [Problem to be solved by the invention]

[0006] The electric fusion pipe joint disclosed in Patent Document 1 has problems in that the large amount of electric power required for fusion and the length of time required for curing after fusion tend to be constraints on construction.

[0007] The joint disclosed in Patent Document 2 can solve the problems of the electric fusion pipe joint disclosed in Patent Document 1. However, the joint disclosed in Patent Document 2 has a problem in that the sealing function of the gasket is easily deteriorated.

[0008] The pipe connection device disclosed in Patent Document 3 can solve the problems of the joint portion disclosed in Patent Document 2. However, the pipe connection device disclosed in Patent Document 3 has a problem in that when the material of a pipe is a synthetic resin, the pipe expands and becomes easily deformed when hot water flows through the pipe, which may cause damage near the connection end of the pipe.

[0009] An object of the present invention is to provide a pipe connection device which can reduce the risk of damage to the vicinity of the connection end of a synthetic resin pipe. [Means for solving the problem]

[0010] The pipe connecting device of the present invention will be described with reference to the drawings. Note that the reference numerals in the drawings are used in this section to facilitate understanding of the contents of the invention, and are not intended to limit the contents to the scope of the drawings.

[0011] In order to achieve the above-mentioned object, according to one aspect of the present invention, the pipe connection device 10 includes a seal ring 20, a plurality of housings 22, 22, and a fastening means 24. The seal ring 20 is for sealing the outer circumferential surface of the connection portion. The connection portion is any portion between a pair of synthetic resin pipes 200, 200 to be connected to each other. The plurality of housings 22, 22 clamp the outer circumferential surface of the seal ring 20. The fastening means 24 presses the seal ring 20 against the connection portion by fastening the ends of the plurality of housings 22, 22. The pipe connection device 10 further includes a protector 62. The protector 62 is arranged to cover a portion 102, among any portion adjacent to the connection portion, where any of the plurality of housings 22, 22 may come into contact as the ends of the plurality of housings 22, 22 are fastened by the fastening means 24.

[0012] The protector 62 is disposed at a location 102, which will be described below, among locations adjacent to the connection location. This location is a location where any of the multiple housings 22, 22 may come into contact with each other as the ends of the multiple housings 22, 22 are fastened by the fastening means 24. The protector 62 is disposed so as to cover this location 102. This reduces the risk that any of the multiple housings 22, 22 will damage the vicinity of the connection end of the synthetic resin pipe 200, even if the synthetic resin pipe 200 expands and becomes easily deformed due to hot water flowing through it.

[0013] It is also desirable that the above-mentioned protector 62 has an outer fitting tubular portion 80 and an annular protruding portion 82. The annular protruding portion 82 protrudes from the outer circumferential surface on the other side of a portion 102 where any one of the multiple housings 22, 22 may come into contact, as viewed from the position of one end portion 100 of the outer fitting tubular portion 80 that faces the connection portion. The annular protruding portion 82 is integral with the outer fitting tubular portion 80.

[0014] The annular protrusion 82 protrudes from the outer circumferential surface of the outer fitting tubular portion 80 on the other side of a point 102 where any one of the multiple housings 22, 22 may come into contact as viewed from the position of one end 100 of the outer fitting tubular portion 80 that faces the connection point. The annular protrusion 82 is integral with the outer fitting tubular portion 80. As a result, even if any one of the multiple housings 22, 22 comes into contact with the outer fitting tubular portion 80 as the multiple housings 22, 22 clamp the outer circumferential surface of the seal ring 20, the outer fitting tubular portion 80 reinforced by the annular protrusion 82 is less likely to deform. As a result, the risk of damage to the vicinity of the connection end of the synthetic resin pipe 200 can be further reduced.

[0015] Alternatively, it is preferable that the annular protrusion 82 protrudes at a position closer to the one end 100 than the other end 104. The other end 104 is on the opposite side of the outer circumferential surface of the outer fitting tubular portion 80 to the one end 100. In this case, since the annular protrusion 82 is closer to the housing 22, even if any of the multiple housings 22, 22 contacts the outer fitting tubular portion 80, the outer fitting tubular portion 80 is less likely to deform. As a result, the risk of damage to the vicinity of the connection end of the synthetic resin pipe 200 can be further reduced.

[0016] Alternatively, it is preferable that the above-mentioned protector 62 further has an other end side protrusion 86. The other end side protrusion 86 protrudes from the outer peripheral surface of the outer fitting tubular portion 80 on the other end 104 side as viewed from the position of the annular protrusion 82. The other end side protrusion 86 is integral with the outer fitting tubular portion 80. In this case, even if the pipe connection device 10 is fixed between the annular protrusion 82 and the other end side protrusion 86 with a known fastener, the outer fitting tubular portion 80 reinforced by the annular protrusion 82 and the other end side protrusion 86 is unlikely to deform. As a result, the risk of the pipe connection device 10 itself being damaged when fixed can be reduced.

[0017] In addition, it is preferable that the above-mentioned pipe connection device 10 further includes a fusion tubular body 60. The fusion tubular body 60 is arranged from the connection point to the adjacent portion of the connection point and across one of the pair of synthetic resin pipes 200, 200. The fusion tubular body 60 is intended to be fused to one end of the pair of synthetic resin pipes 200. In this case, it is preferable that the fusion tubular body 60 has a space forming portion 120, a tightly fitting annular portion 122, and an opposing surface forming portion 124. The space forming portion 120 forms a space communicating with the inside of one of the pair of synthetic resin pipes 200, 200. The tightly fitting annular portion 122 protrudes from the end of the space forming portion 120 on the connection point side. The tightly fitting annular portion 122 is integral with the space forming portion 120. The seal ring 20 is directly in contact with the tightly fitting annular portion 122. The opposing surface forming portion 124 forms a surface opposing the tightly fitting annular portion 122 across the protector 62.

[0018] The tightly contacted annular portion 122 protrudes from the end of the space forming portion 120 on the connection portion side. The tightly contacted annular portion 122 is integral with the space forming portion 120. The seal ring 20 is directly in contact with the tightly contacted annular portion 122. The facing surface forming portion 124 forms a surface facing the tightly contacted annular portion 122 with the protector 62 sandwiched therebetween. In this case, the protector 62 is sandwiched between the tightly contacted annular portion 122 and the facing surface forming portion 124. This makes it difficult for the protector 62 to fall off from the fusion tubular body 60. As a result, the risk of the protector 62 being lost can be reduced.

[0019] In addition, a synthetic resin flow path is formed at a location 102 adjacent to the above-mentioned connection location where any of the multiple housings 22, 22 may come into contact. do. In this case, a gap 130 is formed between the protective body 62 and the portion where the synthetic resin flow path is formed. do. In this case, when the hot water flowing through the synthetic resin pipe 200 flows into the flow path and the flow path expands and becomes easily deformed, the risk of the protective body 62 biting into the outer circumferential surface of the fusion tubular body 60 is reduced. As a result, the risk of damage to the vicinity of the connection end of the synthetic resin pipe 200 can be further reduced. Effect of the Invention

[0020] According to the present invention, the risk of damage to the vicinity of the connection end of the synthetic resin pipe can be reduced. [Brief description of the drawings]

[0021] [Figure 1] 1 is an overall view of a pipe connection device according to an embodiment of the present invention. [Diagram 2] 1 is a diagram showing an internal structure of a pipe connection device according to an embodiment of the present invention; [Diagram 3] FIG. 2 is a diagram showing the internal structure of a shimok according to an embodiment of the present invention. [Figure 4] 1 is an overall view of a fusion tube according to an embodiment of the present invention; [Diagram 5] FIG. 1 is an overall view of a protective body according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are the same. Therefore, detailed descriptions thereof will not be repeated.

[0023] [Configuration of piping connection device] Fig. 1 is an overall view of a pipe connection device 10 according to this embodiment. Fig. 2 is a view showing the internal structure of the pipe connection device 10 according to this embodiment. In Fig. 2, two synthetic resin pipes 200, 200 are connected to the pipe connection device 10 according to this embodiment. In Fig. 2, a part of the pipe connection device 10 is cut away. Hereinafter, the configuration of the pipe connection device 10 according to this embodiment will be described with reference to Figs. 1 and 2.

[0024] The pipe connection device 10 according to this embodiment is used to connect a pair of synthetic resin pipes 200, 200. As is clear from Fig. 1, the pipe connection device 10 according to this embodiment can be fixed by a U-bolt 250 or other well-known fasteners. The pipe connection device 10 according to this embodiment includes a seal ring 20, a pair of housings 22, 22, a pair of fastening means 24, and a pair of shims 26, 26.

[0025] The seal ring 20 is for sealing the connection point. In the case of this embodiment, the connection point is a point where the pair of stubs 26, 26 face each other and contact each other. As a result, the seal ring 20 seals between the pair of synthetic resin pipes 200, 200 to be connected to each other.

[0026] The pair of housings 22, 22 is used to fix the seal ring 20. In the present embodiment, the pair of housings 22, 22 sandwich the outer circumferential surface of the seal ring 20. The configuration of the housing 22 is the same as that of a known one. Therefore, detailed description thereof will not be repeated here.

[0027] The fastening means 24 presses the seal ring 20 against the connection portion by fastening the ends of the housings 22, 22. In this embodiment, the fastening means 24 is realized by well-known bolts and nuts, and therefore, detailed description thereof will not be repeated here.

[0028] The shim 26 is a member for connecting one end of the pair of synthetic resin pipes 200, 200 to the other end of the pair of synthetic resin pipes 200, 200. The pair of shim 26, 26 is connected to the pair of synthetic resin pipes 200, 200 in a one-to-one ratio.

[0029] Fig. 3 is a diagram showing the internal structure of the shield 26 according to this embodiment. The configuration of the shield 26 according to this embodiment will be described below with reference to Figs. 1 to 3. As is clear from Fig. 3, the shield 26 according to this embodiment has a fusion tubular body 60 and a protective body 62.

[0030] The fusion tubular body 60 is to be fused to the end of the synthetic resin pipe 200. In this embodiment, the tip of the synthetic resin pipe 200 is inserted into the fusion tubular body 60. In this state, the outer peripheral surface of the tip of the synthetic resin pipe 200 is fused to the inner peripheral surface of the fusion tubular body 60. As a result, one of the fusion tubular bodies 60 of the shimoku 26 is arranged from the connection point to one of the pair of synthetic resin pipes 200, 200, passing next to the connection point. In addition, the fusion tubular body 60 forms a flow path through which hot water or other fluids flowing inside the synthetic resin pipe 200 flow. In addition, the flow path is arranged at a location (in the case of this embodiment, the expected contact location 102 described later) that may come into contact with any of the locations of the housings 22, 22 (in the case of this embodiment, the inner peripheral side opening edge 170 shown in FIG. 2) among any location next to the connection point. The other fusion tubular body 60 of the bottom plate 26 is disposed across the other of the pair of synthetic resin pipes 200, 200, from the connection point, passing next to the connection point. In the present embodiment, the material of the fusion tubular body 60 is the same as the material of the synthetic resin pipe 200. As a result, the material of the fusion tubular body 60 is a synthetic resin that can be fused to the end of the synthetic resin pipe 200. As a result, the fusion tubular body 60 forms a flow path made of synthetic resin.

[0031] The protective body 62 is fitted onto the outer periphery of the fusion cylindrical body 60. The protective body 62 is disposed so as to cover an assumed contact point 102 (to be described later) of the fusion cylindrical body 60. In the case of this embodiment, the material of the protective body 62 is metal.

[0032] As is clear from FIG. 3, a gap 130 is formed between the portion of the outer circumferential surface of the fusion cylinder 60 where the protector 62 is disposed and the protector 62 .

[0033] Fig. 4 is an overall view of the fusion tubular body 60 according to this embodiment. In Fig. 4, a part of the fusion tubular body 60 is cut away. Hereinafter, the configuration of the fusion tubular body 60 according to this embodiment will be described with reference to Fig. 4. In this embodiment, the fusion tubular body 60 has a space forming portion 120, a close contact annular portion 122, an opposing surface forming portion 124, and a tube end accommodating portion 126.

[0034] The space forming portion 120 forms a cylindrical space that communicates with the inside of the synthetic resin pipe 200. In the case of this embodiment, the diameter of the space formed by the space forming portion 120 is the same as the inner diameter of the synthetic resin pipe 200.

[0035] The tightly contacting annular portion 122 protrudes from the end of the space forming portion 120 on the connection portion side. In this embodiment, the tightly contacting annular portion 122 is integral with the space forming portion 120. In this embodiment, the seal ring 20 is directly in contact with the tightly contacting annular portion 122. The seal ring 20 is in contact with the outer circumferential surfaces of the pair of fusion cylindrical bodies 60, 60 that are in contact with each other. This seals the connection portion described above.

[0036] The facing surface forming portion 124 forms a surface facing the tightly contacting annular portion 122 with the protector 62 sandwiched therebetween, whereby the protector 62 is sandwiched between the tightly contacting annular portion 122 and the surface facing thereto.

[0037] The pipe end accommodating section 126 forms a space in which the synthetic resin pipe 200 is accommodated. In this embodiment, the diameter of the space formed by the pipe end accommodating section 126 is smaller than the outer diameter of the synthetic resin pipe 200. This is because the outer peripheral surface of the tip of the synthetic resin pipe 200 is melted in advance when the tip of the synthetic resin pipe 200 is inserted into the fusion tubular body 60 of the shimoku 26. Therefore, the outer diameter of the synthetic resin pipe 200 is larger than the diameter of the space formed by the pipe end accommodating section 126 by the thickness of the layer that is expected to melt.

[0038] Fig. 5 is an overall view of the protector 62 according to this embodiment. In Fig. 5, a part of the protector 62 is cut away. Hereinafter, the configuration of the protector 62 according to this embodiment will be described with reference to Fig. 5. In this embodiment, the protector 62 has an outer fitting tubular portion 80, an annular protruding portion 82, a one end side protruding portion 84, and an other end side protruding portion 86.

[0039] The outer fitting tubular portion 80 is a tubular portion that serves as the base of the annular protrusion 82. The end of the outer fitting tubular portion 80 that faces the connection point is one end 100. The next location on the outer circumferential surface of the outer fitting tubular portion 80 is the assumed contact location 102. This location is a location where any location of the multiple housings 22, 22 (in the case of this embodiment, the inner circumferential opening edge 170 shown in FIG. 2) may come into contact. The end of the outer fitting tubular portion 80 opposite the one end 100 is the other end 104.

[0040] The annular protrusion 82 protrudes from the outer peripheral surface of the outer fitting cylindrical portion 80 on the other side of the assumed contact point 102 when viewed from the position of the one end 100. In the case of this embodiment, the annular protrusion 82 protrudes from a position on the outer peripheral surface of the outer fitting cylindrical portion 80 adjacent to the inner peripheral opening edge 170 of the housing 22. As a result, the position of the annular protrusion 82 is closer to the one end 100 than to the other end 104. In the case of this embodiment, the shape of the annular protrusion 82 is circular.

[0041] The one-end protrusion 84 protrudes from the position of one end 100 on the outer circumferential surface of the outer fitting cylindrical portion 80. In the case of this embodiment, the one-end protrusion 84 also has an annular shape.

[0042] The other end protrusion 86 protrudes from the position of the other end 104 on the outer circumferential surface of the outer fitting tubular portion 80. As a result, the other end protrusion 86 protrudes from a position on the other end 104 side as viewed from the position of the annular protrusion 82. In this embodiment, the shape of the other end protrusion 86 is also annular.

[0043] [Manufacturing method of pipe connection device] The manufacturing method of the pipe connection device 10 according to this embodiment is as follows. First, the manufacturer manufactures the seal ring 20, the pair of housings 22, 22, the fastening means 24, and the protective body 62 by a known method. After these are manufactured, the manufacturer places the protective body 62 in a mold (not shown). This mold is a mold for manufacturing the fusion tubular body 60. After the protective body 62 is placed in the mold, the manufacturer injects synthetic resin into the mold. When the injected synthetic resin solidifies, the manufacturer removes the die 26 from the mold. That is, the die 26 according to this embodiment is manufactured by insert molding. A more specific procedure for the insert molding is known. Therefore, the detailed description thereof will not be repeated. After the pair of die 26, 26 is manufactured, the manufacturer assembles the seal ring 20, the pair of housings 22, 22, the fastening means 24, and the pair of die 26, 26. This completes the pipe connection device 10 according to this embodiment.

[0044] [How to use the piping connection device] The method of using the pipe connection device 10 according to this embodiment is as follows. In advance, the worker connects one of the pair of synthetic resin pipes 200, 200 to the fusion tubular body 60 of one of the pair of the shims 26, 26, and also connects the other of the pair of the synthetic resin pipes 200, 200 to the fusion tubular body 60 of the other of the pair of the shims 26, 26. To this end, the worker first melts the outer circumferential surface of the tip of the synthetic resin pipe 200 by a known method, and then inserts the tip of the synthetic resin pipe 200 into the fusion tubular body 60 of the shim 26. The molten outer circumferential surface of the tip of the synthetic resin pipe 200 solidifies, and the synthetic resin pipe 200 and the fusion tubular body 60 are fused together. Next, the worker butts the fusion tubular bodies 60 of the pair of the shims 26, 26 together, and brings the seal ring 20 into close contact with the outer circumferential surfaces of the close contact annular portions 122 of the pair of the shims 26, 26. Once the seal ring 20 is in close contact, the worker places the pair of housings 22, 22 over the seal ring 20. Once the pair of housings 22, 22 are placed over the seal ring 20, the worker tightens the ends of the housings 22, 22 with the tightening means 24. In this way, the pair of synthetic resin pipes 200, 200 are connected to each other by the piping connection device 10 according to this embodiment.

[0045] [Explanation of Effects of the Present Embodiment] As described above, in the pipe connection device 10 according to this embodiment, the protector 62 is fitted to the assumed contact location 102 on the outer circumferential surface of the fusion tubular body 60. The protector 62 is fitted so as to cover the assumed contact location 102. This reduces the risk that any of the multiple housings 22, 22 will destroy the fusion tubular body 60 even if the fusion tubular body 60 expands and becomes easily deformed due to the flow of hot water inside the fusion tubular body 60.

[0046] Furthermore, in the case of the pipe connection device 10 according to this embodiment, the annular protrusion 82 protrudes from the outer circumferential surface of the outer fitting tubular portion 80 on the other side of the assumed contact point 102. The annular protrusion 82 is integral with the outer fitting tubular portion 80. As a result, even if any of the multiple housings 22, 22 contacts the outer fitting tubular portion 80 as the multiple housings 22, 22 sandwich the outer circumferential surface of the seal ring 20, the outer fitting tubular portion 80 reinforced by the annular protrusion 82 is unlikely to deform. As a result, the risk of damage to the fusion tubular body 60 is further reduced.

[0047] Moreover, in the case of the pipe connection device 10 according to this embodiment, since the annular protrusion 82 is close to the housing 22, even if any of the multiple housings 22, 22 contacts the outer fitting tubular portion 80, the outer fitting tubular portion 80 is less likely to deform. As a result, the risk of the fusion tubular body 60 being damaged is further reduced.

[0048] Moreover, in the case of the pipe connection device 10 according to this embodiment, even if the pipe connection device 10 is fixed between the annular protrusion 82 and the other end protrusion 86 by a known fastener, the outer fitting tubular portion 80 reinforced by the annular protrusion 82 and the other end protrusion 86 is unlikely to deform. As a result, the pipe connection device 10 itself is less likely to be damaged when it is fixed.

[0049] In addition, in the case of the pipe connection device 10 according to this embodiment, the fusion tubular body 60 can be connected to the synthetic resin pipe 200 in advance. As a result, the possibility that connecting the fusion tubular body 60 to the synthetic resin pipe 200 becomes a constraint on construction is reduced.

[0050] Moreover, in the case of the pipe connection device 10 according to this embodiment, the protector 62 is sandwiched between the tightly contacting annular portion 122 and the opposing surface forming portion 124. This makes it difficult for the protector 62 to fall off from the fusion cylindrical body 60. As a result, the risk of losing the protector 62 is reduced.

[0051] [Variations] The embodiments disclosed herein are illustrative in all respects. The scope of the present invention is not limited to the above-described embodiments. Of course, various design modifications can be made to the above-described embodiments without departing from the spirit of the present invention.

[0052] for example , melt The facing surface forming portion 124 may not be formed on the wearing tubular body 60 .

[0053] Furthermore, the specific locations sealed by the seal ring 20 are not limited to those described above. The locations may be any location between the pair of synthetic resin pipes 200, 200 to be connected to each other. Therefore, the ends of the pair of synthetic resin pipes 200, 200 may be directly sealed by the seal ring 20. In this case, the pair of protectors 62, 62 are fitted one-to-one to the pair of synthetic resin pipes 200, 200. [Explanation of symbols]

[0054] 10...Pipe connection device 20…Seal ring 22. Housing 24... Fastening means 26…Shimoku 60...Cylindrical body for fusion 62...Protection body 80...External fitting cylindrical part 82...Annular protrusion 84...Protrusion on one end side 86...Other end side protrusion 100...One end 102…Expected contact points 104...Other end 120...Space forming part 122…Closed annular part 124…Opposing surface forming part 126... Pipe end housing 130…Gap 170…Inner periphery opening edge 200…Synthetic resin pipe 250…U-bolt

Claims

1. a seal ring for sealing an outer circumferential surface of a connection portion between a pair of synthetic resin pipes to be connected to each other; a plurality of housings that sandwich an outer circumferential surface of the seal ring; A pipe connection device including a fastening means for fastening ends of the housings together to press the seal ring against the connection portion, a protective body arranged to cover a portion of the connection portion adjacent to the connection portion where any of the housings may come into contact with each other as the ends of the housings are fastened by the fastening means; a flow path made of a synthetic resin is formed at a location adjacent to the connection location where any of the plurality of housings may come into contact; The pipe connection device according to claim 1, wherein a gap is formed between the protective body and the location where the synthetic resin flow path is formed.

2. The protector is An outer fitting cylindrical portion; The piping connection device as described in claim 1, characterized in that it has an annular protrusion that protrudes from the outer peripheral surface on the other side of the point at which any of the multiple housings may contact, as viewed from the position of one end of the outer fitting cylindrical portion facing the connection point, and is integral with the outer fitting cylindrical portion.

3. The piping connection device according to claim 2, characterized in that the annular protrusion protrudes at a position closer to the one end than the other end of the outer circumferential surface of the outer fitting cylindrical portion, which is opposite to the one end.

4. The piping connection device as described in claim 2, characterized in that the protective body further has an other end side protrusion protruding from the outer peripheral surface of the other end side of the outer fitting cylindrical portion as viewed from the position of the annular protrusion and being integral with the outer fitting cylindrical portion.

5. the pipe connection device further includes a fusion tubular body arranged across one end of the pair of synthetic resin pipes from the connection point through the adjacent portion of the connection point and to be fused to the one end of the pair of synthetic resin pipes, The fusion tube is a space forming portion that forms a space communicating with the inside of the one of the pair of synthetic resin pipes; a contact annular portion that protrudes from an end of the outer periphery of the space forming portion on the connection portion side, is integral with the space forming portion, and is directly contacted with the seal ring; 2. The pipe connection device according to claim 1, further comprising an opposing surface forming portion that forms a surface opposing the contact annular portion with the protector interposed therebetween.

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