Electric fusion joint

Abstract

To provide a tee type electric fusion joint which achieves excellent workability while improving durability.SOLUTION: An electric fusion joint includes: a branch joint body 12 having a body pipe part 14 having electric fusion sockets 30 formed in at least one end, and a branch pipe part 16 branched from a center part of the body pipe part; and a long-belt-like reinforcement fiber 18 wound around an outer peripheral surface of the body pipe part. The reinforcement fiber is wound around the body pipe part so that power source connection terminals 32 and indicators 34 included in the electric fusion sockets are exposed.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an electric fusion joint, and more particularly to, for example, a Tee-type electric fusion joint including a main pipe portion and a spigot pipe portion having an electric fusion port. [Background technology]

[0002] Patent Document 1 discloses a technique relating to this type of conventional Tee-type pipe joint (branch pipe). The technique of Patent Document 1 includes a resin pipe, a resin branch pipe connected to the resin pipe and configured by joining a branch section to at least a part of a pipe section at a predetermined angle, and a reinforcing layer provided on the outer periphery of the branch pipe. The reinforcing layer is arranged along a shape corresponding to the outer surface shape in the vicinity of the joint between the pipe section and the branch section, and includes a reinforcing member covering the entire outer periphery in the vicinity of the joint, and a fiber reinforcing tape (reinforcing fiber) wrapped around the outer periphery of the branch pipe except at least the portion where the reinforcing member is arranged. The reinforcing member is fixed by a holding member provided on the outer periphery of the reinforcing member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-2489 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology of Patent Document 1, in addition to attaching a reinforcing member to the branch pipe, a fiber reinforcement tape is wrapped around the branch pipe to increase the pressure resistance (internal pressure resistance) of the branched portion of the pipe. In the technology of Patent Document 1, the fiber reinforcement tape is wrapped around the branch pipe after the piping is installed. This is because a resin pipe cannot be connected to the branch pipe when the fiber reinforcement tape is wrapped around the branch pipe. However, after the piping is installed, it is difficult to wrap the fiber reinforcement tape around the branch pipe in a narrow handhole, etc., and there is a risk that the desired pressure resistance cannot be obtained.

[0005] Furthermore, in the technology of Patent Document 1, both ends of the main pipe section of the branch pipe body are plain ends, and no consideration is given to a Tee-type electric fusion joint (EF Tee) having an electric fusion receiving port at the end of the main pipe section.

[0006] SUMMARY OF THE PRESENT EMBODIMENTS It is therefore a primary object of the present invention to provide a novel electrofusion joint.

[0007] Another object of the present invention is to provide an electric fusion joint which has improved pressure resistance and excellent workability. [Means for solving the problem]

[0008] The first invention is a Tee-type electric fusion joint comprising a branch joint body having a main pipe section with an electric fusion port formed at least at one end and a branch pipe section branching off from the center of the main pipe section, and a long strip-shaped reinforcing fiber wrapped around the outer peripheral surface of the main pipe section, the reinforcing fiber being wrapped around the main pipe section so that the power connection terminal and indicator of the electric fusion port are exposed.

[0009] In the first invention, the electric fusion joint is a tee-type electric fusion joint (EF tee) including a branch joint body having a main pipe section having an electric fusion receptacle formed at least at one end and a branch pipe section branched from the center of the main pipe section. A power supply connection terminal and an indicator are provided on the outer circumferential surface of the electric fusion receptacle. The electric fusion joint also includes a long strip-shaped reinforcing fiber wound around the outer circumferential surface of the main pipe section. This reinforcing fiber is wound around the main pipe section so that the power supply connection terminal and the indicator are exposed. By winding the reinforcing fiber around the main pipe section, the pressure resistance (internal pressure resistance characteristics) of the main pipe section and the electric fusion joint are improved. In addition, since the reinforcing fiber is wound around the main pipe section in advance and there is no need to wind the reinforcing fiber during construction, construction quality is stable. Furthermore, since the reinforcing fiber is wound around the main pipe section with the power supply connection terminal and the indicator exposed, the electric fusion joint can be constructed in the same way as a joint without reinforcing fiber.

[0010] According to the first invention, the reinforcing fiber is already wrapped around the main pipe portion so that the power connection terminal and the indicator are exposed, thereby improving the pressure resistance of the electric fusion joint while also improving ease of installation.

[0011] A second invention is dependent on the first invention, and the reinforcing fiber is wound three or more times at a branch intersection portion, which is an intersection portion of the main pipe portion and the branch pipe portion.

[0012] According to the second aspect of the present invention, the pressure resistance of the branch intersection portion can be more appropriately improved, and a pressure resistance applicable to a high-pressure fire extinguishing piping can be obtained.

[0013] The third invention is according to the first or second invention, and the reinforcing fiber is wound diagonally with respect to the axial center of the main pipe section at the branch intersection, which is the intersection of the main pipe section with the branch pipe section, so that the reinforcing fiber overlaps the base end of the branch pipe section and the branch opposing center, which is an extension of the axial center of the branch pipe section.

[0014] According to the third aspect of the present invention, the pressure resistance strength of the branch intersection portion can be improved more appropriately.

[0015] The fourth invention is dependent on the second invention, and the overlap width between the first and second layers of the reinforcing fibers and the overlap width between the second and third layers of the reinforcing fibers at the branch intersection are each at least half the width of the reinforcing fibers.

[0016] According to the fourth aspect of the present invention, the pressure resistance strength of the branch intersection portion can be appropriately improved.

[0017] A fifth invention is according to the first or second invention, and further comprises a protective tape wrapped around an outer circumferential surface of the reinforcing fiber.

[0018] According to the fifth aspect of the present invention, the reinforcing fibers are protected by the protective tape, and therefore the reinforcing fibers can be appropriately prevented from being damaged or deteriorated by ultraviolet rays.

[0019] A sixth invention is dependent on the fifth invention, and the protective tape is provided so as to cover the entire outer peripheral surface of the reinforcing fiber.

[0020] A seventh invention is according to the fifth invention, and the protective tape is provided so as to expose the power connection terminal and the indicator.

[0021] An eighth invention is according to the first or second invention, and includes a long strip-like second reinforcing fiber wound around an outer circumferential surface of the branch pipe portion.

[0022] According to the eighth aspect of the present invention, the pressure resistance of the branch pipe section can be appropriately improved.

[0023] A ninth invention is according to the first or second invention, and the branch pipe section includes a first pipe section and a second pipe section having the same outer diameter as the first pipe section and a larger pipe thickness than the first pipe section, an annular recess having the same inner diameter as the first pipe section is formed on the inner surface of the end of the second pipe section facing the first pipe section, the first pipe section and the second pipe section are connected by butt welding, and a long strip-shaped second reinforcing fiber is provided wound around the outer surface of the first pipe section and the outer surface of the end of the second pipe section facing the first pipe section.

[0024] According to the ninth invention, even when a branch pipe section is formed by butt welding a first pipe section and a second pipe section having different pipe thicknesses, the pressure resistance of the branch pipe section can be appropriately improved while reducing pressure loss. Effect of the Invention

[0025] According to this invention, since reinforcing fiber is wound around the main pipe portion so that the power connection terminal and the indicator are exposed, the pressure resistance of the electric fusion joint can be improved while also improving ease of installation.

[0026] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings. [Brief description of the drawings]

[0027] [Figure 1]1 is a plan view showing an electric fusion joint according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing a branch joint body of an electric fusion joint. [Diagram 3] FIG. 2 is a plan view showing an electric fusion joint with reinforcing fibers wound around the main pipe portion. [Figure 4] FIG. 2 is a plan view showing an electric fusion joint in a state in which reinforcing fibers are wound around a main pipe portion and a branch pipe portion. [Diagram 5] FIG. 4 is a half-sectional view showing a branch pipe portion of an electric fusion joint. [Figure 6] FIG. 6 is an enlarged partial cross-sectional view of a part of FIG. 5. [Figure 7] 11A to 11C are diagrams showing a procedure for winding reinforcing fibers around a main pipe portion. [Figure 8] FIG. 8 is a diagram showing the winding procedure following FIG. 7. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] 1, an electrofusion joint 10 according to one embodiment of the present invention is a Tee-type electrofusion joint (EF Tee), and includes a branch joint body 12 having a main pipe section 14 and a branch pipe section 16. As will be described in detail later, the electrofusion joint 10 includes reinforcing fibers 18 that are wrapped around the outer circumferential surface of the main pipe section 14 in advance (i.e., before construction), thereby increasing the pressure resistance (internal pressure resistance characteristics).

[0029] The use and nominal diameter of the piping constructed using the electric fusion joint 10 are not particularly limited, but since the electric fusion joint 10 has improved pressure resistance, it is suitable for use in high-pressure fire piping for sprinkler equipment or fire hydrant equipment. The nominal diameter (inner diameter) of the piping formed using the electric fusion joint 10 is, for example, 40 mm to 300 mm. In the following, an electric fusion joint 10 provided at a branching portion where a piping with a nominal diameter of 100 mm branches into a piping with a nominal diameter of 100 mm, that is, an electric fusion joint 10 in which the nominal diameters of the main pipe section 14 and the branch pipe section 16 are both 100 mm, will be described as an example. The SDR (Standard Dimension Ratio) described later is a value obtained by dividing the outer diameter of the pipe by the pipe thickness, and if this ratio is constant, the pressure resistance will be the same even if the outer diameter of the pipe changes.

[0030] 1, the electric fusion joint 10 includes a branch joint body 12 having a main pipe section 14 and a branch pipe section 16. The electric fusion joint 10 also includes a reinforcing fiber 18 (first reinforcing fiber) wrapped around the outer circumferential surface of the main pipe section 14, and a second reinforcing fiber 20 wrapped around the outer circumferential surface of the branch pipe section 16. The electric fusion joint 10 also includes a protective tape 22 (first protective tape) wrapped around the outer circumferential surface of the reinforcing fiber 18, and a second protective tape 24 wrapped around the outer circumferential surface of the second reinforcing fiber 20.

[0031] 2, the branch joint body 12 includes a main pipe portion 14 and a branch pipe portion 16, and is made of a polyolefin-based synthetic resin such as polyethylene or polybutene. In this embodiment, the branch joint body 12 is made of polyethylene (specifically, high-density polyethylene).

[0032] The main pipe section 14 has electric fusion sockets 30 at both ends for receiving the ends of a pipe member (not shown) made of synthetic resin. A heating wire (not shown) is embedded in the vicinity of the inner peripheral surface of the electric fusion socket 30 so as to extend in a spiral shape. Both ends of the heating wire are connected to power supply connection terminals 32 formed to protrude from the outer peripheral surface of the electric fusion socket 30. When the power supply connection terminals 32 are connected to a power supply and an electric current is passed through the heating wire, heat is generated. The resin on the joint surface between the electric fusion socket 30 and the pipe member is heated and melted by this heat, and the electric fusion socket 30 and the pipe member are fused and joined. Furthermore, an indicator 34 is formed on the outer peripheral surface of the electric fusion socket 30, closer to the center in the axial direction than the power supply connection terminals 32. The indicator 34 is for indicating that the joint surface between the electric fusion socket 30 and the pipe member has been fused (or the progress of fusion).

[0033] The branch pipe section 16 is formed by protruding from the center of the main pipe section 14. As will be described in detail later, the branch pipe section 16 in this embodiment includes a first pipe section 40 and a second pipe section 42 that has the same outer diameter as the first pipe section 40 and a larger pipe thickness than the first pipe section 40, and is formed by butt welding these sections. Therefore, a bead section 44 is formed at the connecting portion between the first pipe section 40 and the second pipe section 42.

[0034] In the electric fusion joint 10 having such a branch joint body 12, it is possible to wind fiber reinforcement around the outer circumferential surface of the branch joint body 12 in order to increase the pressure resistance (internal pressure resistance) of the joint. However, the method of winding fiber reinforcement around the branch joint body 12 after the piping is installed, as in the conventional technology, is difficult to install and may not provide the desired pressure resistance. In addition, the pressure resistance of both ends of the main pipe section 14 and the branch pipe section 16 can be easily improved by winding reinforcing fibers in the circumferential direction. On the other hand, the central section of the main pipe section 14, that is, the branch intersection section 14a which is the intersection with the branch pipe section 16, needs to be wound with reinforcing fibers while avoiding the branch pipe section 16, so some ingenuity is required to appropriately improve the pressure resistance.

[0035] Therefore, in this embodiment, the reinforcing fiber 18 is wound around the outer peripheral surface of the main pipe portion 14 in advance as described below, thereby improving the pressure resistance of the main pipe portion 14 and therefore the electric fusion joint 10, and improving the workability of the electric fusion joint 10. A specific explanation will be given below. However, Fig. 3 shows the electric fusion joint 10 in a state where the second reinforcing fiber 20 and the protective tapes 22, 24 described later are omitted, and Fig. 4 shows the electric fusion joint 10 in a state where the protective tapes 22, 24 are omitted.

[0036] As shown in Fig. 3, the electric fusion joint 10 includes a long strip-shaped reinforcing fiber 18 wound around the outer circumferential surface of the main pipe section 14. The reinforcing fiber 18 is made of high-strength fibers such as polyarylate fibers, aramid fibers, carbon fibers, and ultra-high molecular weight polyethylene fibers. The tensile strength of the reinforcing fiber 18 is, for example, 280 kg / mm 2 In this embodiment, Vectran (registered trademark) manufactured by Kuraray Co., Ltd., which is a polyarylate fiber, is used as the reinforcing fiber 18, and the tensile strength thereof is preferably 290 [kg / mm 2 ].

[0037] The reinforcing fiber 18 is wound around the main pipe portion 14 so that the power connection terminal 32 and the indicator 34 of the electric fusion socket 30 are exposed. This allows other pipe members to be connected to the electric fusion socket 30 in the same way as a joint without the reinforcing fiber 18. The reinforcing fiber 18 is composed of a single strip of material that is continuous in the circumferential direction (i.e., not cut in the longitudinal direction). This allows the expansion of the main pipe portion 14 due to internal pressure to be appropriately suppressed (i.e., pressure resistance to be increased). The width of the reinforcing fiber 18 is preferably 50 mm to 70 mm, for example, and is 60 mm in this embodiment.

[0038] In addition, the reinforcing fiber 18 is preferably wound around both ends of the main pipe portion 14 over at least the entire circumferential length (i.e., one or more turns). In addition, it is preferable to wind the reinforcing fiber 18 three or more times around the branch intersection portion 14a. The branch intersection portion 14a is a portion with low pressure resistance because a branch hole communicating with the branch pipe portion 16 is formed therein, but by winding the reinforcing fiber 18 three or more times around the branch intersection portion 14a, the pressure resistance of the branch intersection portion 14a (and therefore the electric fusion joint 10) can be appropriately improved. In particular, the effect of improving pressure resistance is greatly exhibited in the electric fusion joint 10 in which the main pipe portion 14 and the branch pipe portion 16 have the same diameter and the opening area of ​​the branch hole is large. According to a verification experiment by the inventors, it was confirmed that the breaking water pressure of the electric fusion joint 10 of this embodiment is 7.4 MPa by winding the reinforcing fiber 18 three times around the branch intersection portion 14a, which satisfies the pressure resistance standard (6.5 MPa) for high-pressure fire extinguishing piping with a sufficient margin.

[0039] In addition, at the branch intersection 14a, the reinforcing fiber 18 is preferably wound in a diagonal direction with respect to the axial center of the main pipe 14 so that it covers the base end 16a (rising portion) of the branch pipe 16 and the branch opposing center portion 14b, which is an extension of the axial center of the branch pipe 16. This allows the base end 16a of the branch pipe 16, i.e., the peripheral portion of the branch hole formed in the main pipe 14, to be appropriately reinforced. Furthermore, the reinforcing fiber 18 wound in multiple layers (i.e., multiple windings) at the branch intersection 14a is preferably wound so as not to shift in the width direction as much as possible, but it can also be wound so as to shift in the width direction. However, it is preferable that the overlap width between the first and second layers of the reinforcing fiber 18 and the overlap width between the second and third layers at the branch intersection 14a are at least half the width of the reinforcing fiber 18. In other words, the offset width between the vertically overlapping reinforcing fibers 18 is preferably less than half the width of the reinforcing fiber 18 (60 mm in this embodiment) (less than 30 mm in this embodiment).

[0040] 4 to 6, the electric fusion joint 10 further includes a long strip-like second reinforcing fiber 20 wound around the outer circumferential surface of the branch pipe portion 16. The second reinforcing fiber 20 is preferably wound around the branch pipe portion 16 at least once in the circumferential direction, and is preferably wound two or three times.

[0041] In addition, the branch pipe section 16 of this embodiment includes a first pipe section 40 formed on the base end side and a second pipe section 42 formed on the tip end side, and is formed by butt welding these. The second pipe section 42 has the same outer diameter as the first pipe section 40 and a pipe thickness larger than that of the first pipe section 40. In other words, the second pipe section 42 has a smaller SDR than the first pipe section 40, and the branch pipe section 16 is formed by connecting pipe sections with different SDRs. In this embodiment, the outer diameters of the first pipe section 40 and the second pipe section 42 are each 125 mm. In addition, the first pipe section 40 has a pipe thickness specification of SDR11, and its pipe thickness t1 is, for example, 11.4 mm, and its inner diameter d1 is, for example, 102 mm. On the other hand, the second pipe section 42 has a pipe thickness specification of SDR9, and its pipe thickness t2 is, for example, 14.0 mm, and its inner diameter d2 is, for example, 97 mm.

[0042] In this embodiment, an annular recess 46 having a diameter d3 equal to the inner diameter d1 of the first pipe section 40 is formed on the inner circumferential surface of the end of the second pipe section 42 on the first pipe section 40 side. That is, the pipe thickness t3 of the portion of the second pipe section 42 where the recess 46 is formed (the end of the second pipe section 40 side) is equal to the pipe thickness t1 of the first pipe section 40. By forming such a recess 46 in the second pipe section 42 and then connecting the first pipe section 40 and the second pipe section 42 by butt welding, the shapes and sizes of the end faces of the first pipe section 40 and the second pipe section 42 match, so that optimal joint strength can be obtained. In addition, since the bead section 44 does not protrude significantly from the inner circumferential surface of the second pipe section 42, the pressure loss occurring at the connecting portion between the first pipe section 40 and the second pipe section 42 can be reduced.

[0043] The size of the recess 46 is not particularly limited, but the axial length A of the recess 46 is preferably 0.03 to 0.60 times the diameter d3 of the recess 46. The axial length A of the recess 46 is preferably 0.3 to 4.5 times the pipe thickness t3 of the portion of the second pipe section 42 where the recess 46 is formed. This is because the pressure loss occurring at the connecting portion between the first pipe section 40 and the second pipe section 42 can be more appropriately reduced.

[0044] Furthermore, a tapered section 48 is formed on the wall of the recess 46 on the opposite side to the first pipe section 40 (i.e., the downstream side), the diameter of which decreases with increasing distance from the first pipe section 40. By providing the tapered section 48, pressure loss can be reduced more appropriately. The inclination angle θ of the tapered section 48 with respect to the axial direction is not particularly limited, but is preferably set to 25 degrees or more and 45 degrees or less. By setting the inclination angle θ of the tapered section 48 within this range, the stress in the tapered section 48 is effectively reduced, and a reduction in the strength of the connecting portion between the first pipe section 40 and the second pipe section 42 can be suppressed.

[0045] In this embodiment, the second reinforcing fiber 20 is wound so as to cover the outer peripheral surface of the first pipe section 40 and the outer peripheral surface of the end of the second pipe section 42 on the first pipe section 40 side. When winding the second reinforcing fiber 20 around the end of the second pipe section 42 on the first pipe section 40 side, it is preferable to wind the fiber so as to include at least the portion where the recess 46 and the tapered portion 48 are formed. This appropriately reinforces the portion of the branch pipe section 16 where the pipe thickness is small, and therefore the pressure resistance of the branch pipe section 16 and the electric fusion joint 10 can be appropriately improved. Furthermore, when winding the second reinforcing fiber 20 around the end of the second pipe section 42 on the first pipe section 40 side, it is preferable to wind the fiber so as to extend from the edge of the tapered portion 48 on the opposite side to the first pipe section 40 to a portion 5 mm to 50 mm on the opposite side to the first pipe section 40. That is, when the axial length of the recess 46 is A, the axial length of the tapered portion 48 is B, and the axial length from the edge of the recess 46 on the first pipe portion 40 side to the tip of the second reinforcing fiber 20 is C, it is preferable to wind the second reinforcing fiber 20 around the branch pipe portion 16 so that the relationship 5≦C-(A+B)≦50 [mm] is satisfied. This allows the branch pipe portion 16 to be reinforced more appropriately.

[0046] Returning to FIG. 1, in the electric fusion joint 10 of this embodiment, a protective tape 22 is wound around the outer circumferential surface of the reinforcing fiber 18, and a second protective tape 24 is wound around the outer circumferential surface of the second reinforcing fiber 20. These protective tapes 22, 24 are members for protecting the reinforcing fiber 18 and the second reinforcing fiber 20 from ultraviolet rays, external damage, and the like. In this embodiment, the protective tapes 22, 24 are made of Varco Tape (registered trademark) manufactured by Furukawa Electric Co., Ltd. When the protective tapes 22, 24 are wound around the outer circumferential surfaces of the reinforcing fiber 18 and the second reinforcing fiber 20, a part of the reinforcing fiber 18 or the second reinforcing fiber 20 may be exposed, but it is preferable to provide the protective tapes 22, 24 so as to cover the entire outer circumferential surfaces of the reinforcing fiber 18 and the second reinforcing fiber 20. The protective tape 22 is wound around the main pipe portion 14 so that the power supply connection terminal 32 and the indicator 34 are exposed. As a result, even when the protective tape 22 is provided, other pipe members can be connected to the electric fusion receiving port 30 in the same way as a joint that does not have the protective tape 22.

[0047] In this way, by providing the electric fusion joint 10 with the protective tapes 22, 24 in advance, the workability of the electric fusion joint 10 can be maintained while appropriately preventing the reinforcing fiber 18 and the second reinforcing fiber 20 from being deteriorated or damaged by ultraviolet rays.

[0048] Next, referring to Fig. 7 and Fig. 8, an example of a method for winding the reinforcing fiber 18 around the main pipe section 14 of the branch joint body 12 will be described. As shown in Fig. 7(a), winding of the reinforcing fiber 18 is started from one end of the main pipe section 14. For example, the reinforcing fiber 18 is wound around one circumferential turn from the apex of the main pipe section 14 so as not to cover the power connection terminal 32 and the indicator 34, and then wound in this manner for three-quarters of a turn. Next, as shown in Fig. 7(b), when the reinforcing fiber 18 reaches the position of the branch pipe section 16, the reinforcing fiber 18 is wound obliquely toward the branch-facing center section 14b while hanging the reinforcing fiber 18 around the base end section of the branch pipe section 16. Next, as shown in Fig. 7(c), after passing through the branch-facing center section 14b, the reinforcing fiber 18 is wound obliquely toward the base end section of the branch pipe section 16 on the other end side of the main pipe section 14. Then, when the reinforcing fiber 18 reaches the position of the branch pipe section 16, the reinforcing fiber 18 is wound diagonally toward the branch-facing center section 14b while hanging it around the base end of the branch pipe section 16. Then, as shown in Fig. 8(a) and Fig. 8(b), the same operation is repeated to wind the reinforcing fiber 18 three times around the branch intersection section 14a of the main pipe section 14. Thereafter, as shown in Fig. 8(c), the reinforcing fiber 18 is wound around the other end of the main pipe section 14, and the winding operation of the reinforcing fiber 18 around the main pipe section 14 is completed. At this time, for example, it is preferable to wind the reinforcing fiber 18 one turn in the circumferential direction from the base end of the branch pipe section 16 so as not to cover the power connection terminal 32 and the indicator 34, and then wind it one-quarter turn up to the apex of the main pipe section 14.

[0049] In addition, since there is nothing to obstruct the second reinforcing fibers 20 that are wound around the outer circumferential surface of the branch pipe portion 16, it is sufficient to simply wind them in the circumferential direction (spiral shape) as usual.

[0050] As described above, according to this embodiment, the reinforcing fiber 18 is wound around the main pipe portion 14, thereby improving the pressure resistance of the main pipe portion 14 and therefore the electric fusion joint 10. Furthermore, since the reinforcing fiber 18 is provided in advance with the power connection terminal 32 and the indicator 34 exposed, there is no need to wind the reinforcing fiber 18 during construction, and construction quality is stable. Furthermore, the electric fusion joint 10 can be constructed in the same way as one that does not have the reinforcing fiber 18. Therefore, the pressure resistance of the electric fusion joint 10 can be improved while improving construction ease.

[0051] In the above embodiment, the main pipe section has electric fusion ports at both ends, but the main pipe section only needs to have an electric fusion port at at least one end. In the above embodiment, the branch pipe section is formed by butt welding the first and second pipe sections with different SDRs, but the branch pipe section may be formed with a uniform pipe thickness. The branch pipe section may have a reducer structure, a flange structure, or the like.

[0052] Furthermore, the specific values ​​and specific configurations such as dimensions given above are merely examples and can be changed as appropriate according to the needs of product specifications, etc. [Explanation of symbols]

[0053] 10... Electric fusion joint 12 …Branch joint body 14 …Main Division 14a … Branch intersection 14b … Center of branch facing 16 ... Branch pipe section 18...Reinforcing fiber 20...Second reinforcing fiber 22 ... Protective tape 24 ...Second protective tape 30... Electric fusion socket 32 ... Power supply connection terminal 34 ... Indicator

Claims

1. A Tee-type electrofusion joint, A branch joint body having a main pipe portion having an electric fusion receiving port formed at least at one end thereof and a branch pipe portion branching from a central portion of the main pipe portion; A long strip-shaped reinforcing fiber is provided wound around the outer circumferential surface of the main pipe portion, an electric fusion joint, wherein the reinforcing fiber is wrapped around the main pipe portion so that a power supply connection terminal and an indicator of the electric fusion receiving port are exposed;

2. 2. The electric fusion joint according to claim 1, wherein the reinforcing fiber is wound three or more times at a branch intersection where the main pipe section intersects with the branch pipe section.

3. 3. The electric fusion joint according to claim 1, wherein the reinforcing fiber is wound in a direction oblique to the axial center of the main pipe section at a branch intersection where the main pipe section intersects with the branch pipe section, so as to overlap a base end of the branch pipe section and an opposing center of the branch pipe section, which is an extension of the axial center of the branch pipe section.

4. 3. The electric fusion joint according to claim 2, wherein the overlap width between the first and second layers of the reinforcing fibers and the overlap width between the second and third layers of the reinforcing fibers at the branch intersection are each at least half the width of the reinforcing fibers.

5. 3. The electric fusion joint according to claim 1, further comprising a protective tape wrapped around an outer peripheral surface of the reinforcing fiber.

6. 6. The electric fusion joint according to claim 5, wherein the protective tape is provided so as to cover the entire outer circumferential surface of the reinforcing fiber.

7. 6. The electric fusion joint according to claim 5, wherein the protective tape is provided so that the power supply connection terminal and the indicator are exposed.

8. 3. The electric fusion joint according to claim 1, further comprising a second reinforcing fiber in the form of a long strip wound around an outer circumferential surface of the branch pipe portion.

9. The branch pipe portion includes a first pipe portion and a second pipe portion having the same outer diameter as the first pipe portion and a pipe thickness larger than that of the first pipe portion, an annular recess having the same diameter as an inner diameter of the first pipe portion is formed on an inner circumferential surface of an end portion of the second pipe portion on the first pipe portion side, and the first pipe portion and the second pipe portion are connected by butt welding, 3. The electric fusion joint according to claim 1, further comprising a long strip-like second reinforcing fiber wound around an outer circumferential surface of the first pipe portion and an outer circumferential surface of an end portion of the second pipe portion on the first pipe portion side.

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