JP2022142286A - Connection method and piping structure - Google Patents

Abstract

To provide a connection method which can suppress the formation of a clearance and an irregular rise of resin.SOLUTION: Step S1 in a connection method heats a pipe end 11a of a resin pipe 11 including a thermoplastic resin, and a pipe end 12a of a resin pipe 12 including a thermoplastic resin. Step S3 brings the pipe end 11a of the resin pipe 11 inserted to the inside of a joint receptacle part 23 arranged at one end of both ends of an electrical fusion joint 1, and a pipe end 12a of the resin pipe 12 inserted to the inside of a joint receptacle part 24 arranged at the other side into contact with each other at the inside of the electrical fusion joint 1, and fuses the pipe ends 11a, 12a to each other. Step S4 fuses the joint receptacle part 23 and the resin pipe 11 to each other by carrying electricity to a receptacle power generation part 3 arranged at the joint receptacle part 23 and including a heating wire 31, and fuses the joint receptacle part 24 and the resin pipe 12 to each other by carrying electricity to the receptacle power generation part 4 arranged at the joint receptacle part 24 and including the heating wire 31.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present disclosure relates to a method of connecting an electric fusion joint and a pipe, and a pipe structure.

Electric fusion joints are often used when connecting pipes using resin such as resin pipes and metal-reinforced composite pipes having a resin layer and a metal reinforcing layer (see, for example, Patent Documents 1 and 2). .

For example, the electric fusion joint shown in Patent Document 1 includes a joint body made of thermoplastic resin, in which pipe sockets into which pipes to be connected are inserted are formed at both ends, and an inner peripheral surface of the joint body. A stopper portion projecting toward is provided. The stopper portion regulates the position of the pipe inserted into the pipe socket. A heating element is provided in each of the pipe socket and the stopper portion, and by heating the heating element, the resin around the heating element and the resin of the pipe are fused to connect the electric fusion joint and the pipe. .

For example, the electrofusion pipe joint shown in Patent Document 2 is a joint for butt-joining two thermoplastic pipes, and is a thermoplastic ring-shaped body having an inner and outer diameter equal to the inner and outer diameters of the pipes to be joined. , a heating wire laid on the end face of the ring-shaped main body, and a terminal for supplying electricity to the heating wire. The coupling and the pipe are fused together by heating the heating wire while the pipe is in contact with the ring-shaped body.

JP-A-5-87286 JP-A-9-144983

However, in Patent Document 1, since the stopper portion and the pipe receiving port are fused at two locations at the same time, the air trapped between the two locations expands due to heat, making it easier for the resin to blow out, and In some cases, the height of the rising resin becomes uneven in the circumferential direction. In addition, when air is mixed into the resin and the mixed air is expanded and bursts, the resin that rises inward may be dented.

Moreover, in Patent Document 2, since butt fusion is performed using an electric fusion joint, it may be difficult to sufficiently heat, and a gap (clevis) may occur.

If uneven resin rises or crevices are formed, turbulent flow will occur, making it easier for some water or chemicals to stay in the piping. As a result, there is a possibility that microorganisms will propagate and cause deterioration of water quality, and that deterioration of the chemical solution will cause a decrease in purity.

An object of the present disclosure is to provide a connection method and a piping structure capable of suppressing formation of gaps and uneven swelling of resin.

To achieve the above object, a connection method according to a first aspect includes a pipe end heating step, a first fusion step, a second fusion step, and a third fusion step. The tube end heating step heats the tube end of the first tube containing the thermoplastic resin and the tube end of the second tube containing the thermoplastic resin. In the first fusion step, after the pipe end heating step, the pipe end of the first pipe inserted into the first joint receptacle provided at one of the ends of the electric fusion joint and the pipe end provided at the other end of the electric fusion joint. The pipe ends of the second pipe inserted into the second joint receptacle are brought into contact with each other inside the electric fusion joint to fuse the pipe ends. In the second fusion step, the first joint socket portion and the first pipe are fused together by energizing the first socket heating portion, which is arranged in the first joint socket portion and includes a heating wire. In the third fusing step, the second joint socket portion and the second pipe are fused by energizing the second socket heat generating portion which is arranged in the second joint socket portion and includes a heating wire.

In this way, after the pipe ends of the first pipe and the second pipe are fused together, the outer circumferential surface of the first pipe and the inner circumferential surface of the first joint receptacle portion, and the outer circumferential surface of the second pipe and the second pipe are separated. Since the inner peripheral surfaces of the two joint receptacles are fused together, the expanded air can escape, the air is not trapped, and the height of the resin rising inside can be made uniform.

Since the tube end of the first tube and the tube end of the second tube are joined by butt fusion, there is more space between the first tube and the second tube than in the conventional fusion only by heating the heating wire. Gaps are less likely to occur.

Also, by performing butt fusion, the size of the bead can be reduced to the extent that air is not entrained. Conventionally, the resin of the electrofusion joint other than the stopper portion is also melted and incorporated into the bead resin. can be done.

A connection method according to a second aspect includes a pipe end heating step, a stopper heating step, a first fusion bonding step, a second fusion bonding step, and a third fusion bonding step. The tube end heating step heats the tube end of the first tube containing the thermoplastic resin and the tube end of the second tube containing the thermoplastic resin. In the step of heating the stopper, a stopper portion is provided on the inner surface of the tubular portion of the electric fusion joint so as to protrude inward, and the stopper heating portion including the heating wire is energized and heated. In the first fusing step, after the pipe end heating step, the pipe end of the first pipe inserted into the inside of the first joint receiving portion provided on one of both ends of the cylindrical portion and the pipe end provided on the other The pipe end of the second pipe inserted inside the second joint socket portion is fused to the stopper portion. In the second fusion step, the first joint socket portion and the first pipe are fused together by energizing the first socket heating portion, which is arranged in the first joint socket portion and includes a heating wire. In the third fusing step, the second joint socket portion and the second pipe are fused by energizing the second socket heat generating portion which is arranged in the second joint socket portion and includes a heating wire.

Thus, after the pipe ends of the first pipe and the second pipe are fused to the stopper portion, the gap between the outer peripheral surface of the first pipe and the inner peripheral surface of the first joint receptacle portion and the outer peripheral surface of the second pipe and the inner peripheral surface of the second joint receptacle are fused, the expanded air can escape, the air is not trapped, and the height of the resin rising inside can be made uniform. .

Not only the stopper portion is heated, but also the tube ends of the first tube and the tube end of the second tube are heated and fused with the stopper portion. A gap is less likely to occur between the first pipe and the second pipe.

Also, by performing butt fusion, the size of the bead can be reduced.

A connection method according to a third aspect is the connection method according to the second aspect, in which the first fusion step is performed after energization of the stopper heat generating portion in the stopper heating step is completed.

In this manner, after the heating of the stopper portion is finished, the heated pipe ends of the first pipe and the heated second pipe are fused to the stopper portion, so that the generation of gaps can be suppressed.

A connection method according to a fourth aspect is the connection method according to any one of the first to third aspects, wherein the second fusion step and the third fusion step are performed simultaneously.
As a result, the first joint receptacle and the first pipe and the second joint receptacle and the second pipe can be fused at the same time.
A piping structure according to a fifth aspect includes a first pipe, a second pipe, and an electrofusion joint. The first tube contains a thermoplastic resin. The second tube contains a thermoplastic resin. The electric fusion joint is arranged in the first joint receptacle into which the first pipe is inserted, the second joint receptacle into which the second pipe is inserted, and the first joint receptacle, and includes a heating wire. It has a first receptacle heat-generating part and a second receptacle heat-generating part arranged at the second joint receptacle part and including a heating wire. The tube end of the first tube and the tube end of the second tube are butted and fused together inside the electric fusion joint.

After the pipe ends of the first pipe and the second pipe are fused together, the outer peripheral surface of the first pipe and the inner peripheral surface of the first joint receptacle portion and the outer peripheral surface of the second pipe and the second joint receptacle are separated. Since the inner peripheral surfaces of the portions can be fused together, air is not trapped, and the height of the resin rising inside can be made uniform.

Since the tube end of the first tube and the tube end of the second tube are joined by butt fusion, there is more space between the first tube and the second tube than in the conventional fusion only by heating the heating wire. Gaps are less likely to occur.

Advantageous Effects of Invention According to the present disclosure, it is possible to provide a connection method and a piping structure capable of suppressing formation of gaps and uneven swelling of resin.

1 is an external view showing an electrical fusion joint, a resin pipe connected to the electrical fusion joint, and a resin pipe according to the first embodiment of the present disclosure; FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional configuration diagram showing an electric fusion joint according to Embodiment 1 of the present disclosure; FIG. 2 is a cross-sectional configuration diagram showing a resin pipe and a state in which the resin pipe is inserted into the electric fusion joint according to the first embodiment of the present disclosure; FIG. 2 is a schematic diagram of an electric fusion joint showing a connection relationship between a socket heat-generating portion and a stopper heat-generating portion of the electric fusion joint according to Embodiment 1 of the present disclosure, and a connector mounting portion; FIG. 2 is a perspective view showing a jig used in the connection method according to Embodiment 1 of the present disclosure; FIG. 2 is a perspective view showing a state in which an electric fusion joint and two resin pipes are attached to a jig in the connection method according to the first embodiment of the present disclosure; FIG. 2 is a front view showing a state in which an electric fusion joint and two resin pipes are attached to a jig in the connection method according to the first embodiment of the present disclosure; FIG. 2 is a flowchart showing a connection method according to the first embodiment of the present disclosure; FIG. (a) A diagram for explaining the heating of the pipe end of the resin pipe in the connection method of the first embodiment according to the present disclosure, (b) the electric fusion joint in the connection method of the first embodiment according to the present disclosure The figure for demonstrating insertion of a resin pipe. (a) Diagram for explaining the fusion between the ends of resin pipes in the connection method according to the first embodiment of the present disclosure, (b) Electric fusion joint in the connection method according to the first embodiment of the present disclosure Fig. 3 is a view for explaining fusion bonding between the joint receiving portion and the resin pipe; The schematic diagram which shows the bead by which resin rose uniformly. FIG. 4 is a cross-sectional configuration diagram showing an electric fusion joint according to Embodiment 2 of the present disclosure; FIG. 5 is a cross-sectional configuration diagram showing a resin pipe and a state in which the resin pipe is inserted into an electric fusion joint according to a second embodiment of the present disclosure; FIG. 10 is a schematic diagram of an electric fusion joint showing a connection relationship between a socket heat-generating portion and a stopper heat-generating portion of the electric fusion joint and two connector mounting portions having a pair of pins according to the second embodiment of the present disclosure; FIG. 10 is a flowchart showing a connection method according to the second embodiment of the present disclosure; FIG. (a) A diagram for explaining the heating of the pipe end of the resin pipe in the connection method of the second embodiment according to the present disclosure, (b) the embodiment according to the present disclosure (a) A diagram for explaining insertion of a resin pipe into an electric fusion joint in the connection method of the second embodiment according to the present disclosure, (b) Electric fusion in the connection method of the second embodiment according to the present disclosure FIG. 4 is a view for explaining fusion bonding between a stopper portion of a joint and a pipe end of a resin pipe; FIG. 10 is a diagram for explaining fusion between a joint socket portion of an electric fusion joint and a pipe end of a resin pipe in the connection method of the second embodiment according to the present disclosure; FIG. 2 is a cross-sectional view showing the configuration of an electrofusion joint of a comparative example; (a) and (b) are diagrams for explaining the fusion process in the electrical fusion joint of the comparative example. FIG. 4 is a schematic diagram showing a state in which the resin rises unevenly.

Embodiments according to the present disclosure will be described below with reference to the drawings.

(Embodiment 1)
A piping structure and a connection method in Embodiment 1 according to the present disclosure will be described below.

<Configuration>
(Overview of Piping Structure 100)
FIG. 1 is an exploded view of a piping structure 100 according to Embodiment 1 of the present disclosure. The piping structure 100 of Embodiment 1 includes an electric fusion joint 1, a resin pipe 11 (an example of a pipe containing a thermoplastic resin), and a resin pipe 12 (an example of a pipe containing a thermoplastic resin). ing.

As shown in the figure, the electrical fusion joint 1 is fused to a resin pipe 11 and a resin pipe 12 to connect the resin pipe 11 and the resin pipe 12 .

The resin pipe 11 and the resin pipe 12 are each made of thermoplastic resin.

Channels 11 f and 12 f having a circular cross section extend inside the resin pipes 11 and 12 . In the electric fusion joint 1, a channel 1f having a circular cross section extends inside. When the resin pipe 11 and the resin pipe 12 are connected by the electric fusion joint 1, the respective flow path axes of the resin pipe 11, the resin pipe 12, and the electric fusion joint 1 are arranged on the same straight line.

The axial direction A is the direction in which the respective axes of the electric fusion joint 1 , the resin pipe 11 , and the resin pipe 12 extend with respect to the flow path. In the electric fusion joint 1, the resin pipe 11, and the resin pipe 12, the radial direction B is the direction perpendicular to the respective axes, and the circumferential direction C is the direction around the respective axes.

The resin pipe 11 moves relative to the electric fusion joint 1 in the axial direction A in the arrow A1 direction and is connected to the electric fusion joint 1 . Further, the resin pipe 12 is moved relative to the electric fusion joint 1 in the axial direction A in the arrow A2 direction and connected to the electric fusion joint 1 . A state in which the resin pipe 11 and the resin pipe 12 are connected to the electric fusion joint 1 constitutes a piping structure 100 .

FIG. 2 is a diagram showing a cross-sectional configuration of the electrofusion joint 1. As shown in FIG.

The electric fusion joint 1 has a cylindrical portion 21, socket heat generating portions 3 and 4, and a connector mounting portion 5, as shown in FIGS.

(cylindrical portion 21)
The tubular portion 21 is made of a thermoplastic resin, and has a tubular shape as shown in FIG. One end along the axial direction A of the cylindrical portion 21 is defined as an end 21b, and the other end is defined as an end 21c. The cylindrical portion 21 has a joint socket portion 23 and a joint socket portion 24 . The resin pipe 11 is inserted inside the joint receiving portion 23 . The resin pipe 12 is inserted inside the joint receiving portion 24 . The joint socket portion 23 is provided on the opposite side of the joint socket portion 24 . The joint socket portion 23 is a portion on the end 21b side of the tubular portion 21 , and the joint socket portion 24 is a portion on the end 21c side of the tubular portion 21 . The end of the joint socket portion 23 opposite to the end 21b and the end of the joint socket portion 24 opposite to the end 21c are connected.

The thermoplastic resin used for the cylindrical portion 21 is not particularly limited, but preferably has a melting point of less than 230°C. As the thermoplastic resin, for example, polyethylene is used in the first embodiment. Moreover, the thermoplastic resin is not particularly limited, and for example, an olefin-based resin, a vinyl chloride resin, or the like can be used.

Moreover, the polyolefin resin is not particularly limited, but for example, polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer, and the like can be used. From the viewpoint of more effectively increasing the strength, dimensional stability and elongation at high temperatures of the multilayer pipe, polyethylene or polypropylene is preferable, and polyethylene is more preferable.

Moreover, LDPE, LLDPE, HDPE, etc. are mentioned as said polyethylene (PE). HDPE is more preferable from the viewpoint of increasing the strength of the multilayer pipe material more effectively.

FIG. 3 is a cross-sectional configuration diagram showing a state in which the resin pipe 11 is inserted inside the joint socket portion 23 of the electrical fusion joint 1 and the resin pipe 12 is inserted inside the joint socket portion 24 .

The inner diameter of the joint receiving portion 23 is formed to be equal to or larger than the outer diameter of the resin pipe 11 . Also, the inner diameter of the joint receiving portion 24 is formed to be equal to or larger than the outer diameter of the resin pipe 12 .

(Receptacle heat generating parts 3 and 4)
FIG. 4 is a schematic diagram of the electrical fusion joint 1 showing the connection relationship between the socket heat generating portions 3 and 4 and the connector mounting portion 5. As shown in FIG.

The socket heat generating portion 3 is provided in the joint socket portion 23 as shown in FIGS. 2 and 4 . The socket heat generating portion 4 is provided in the joint socket portion 24 .

The socket heat generating portion 3 has a heating wire 31 embedded in the inner surface 21 a of the joint socket portion 23 . The socket heat generating portion 4 has a heating wire 31 embedded in the inner surface 21 a of the joint socket portion 24 . The heating wire 31 is arranged so as to be wound in the circumferential direction along the inner surface 21 a of the joint socket portion 23 and the joint socket portion 24 . The heating wire 31 is arranged near the inner surface 21a. The heating wire 31 may be partially embedded in the cylindrical portion 21 so as to be exposed on the flow path 1f side, or may be completely embedded.

A portion of the heating wire 31 disposed at the joint socket portion 23 is referred to as a heating wire portion 31a, and a portion of the heating wire 31 disposed at the joint socket portion 24 is referred to as a heating wire portion 31b. The heating wire portion 31a and the heating wire portion 31b of the heating wire 31 are connected by a heating wire portion 31c arranged so as to be wound in the circumferential direction. Note that the heating wire portion 31c may not be arranged so as to be wound, and may be arranged parallel to the axial direction A as shown in FIG. 14 described later, for example.

In the present embodiment, one heating wire 31 is arranged over the joint socket portion 23 and the joint socket portion 24, but the heating wire portion 31a and the heating wire portion 31b are separate heating wires. and the heating wires may be connected.

The heating wire 31 preferably has a conducting wire and an insulating coating, but it may have only a conducting wire without the insulating coating. As the conducting wire, for example, a nichrome wire, an iron-chromium class 2 wire, an iron-chromium class 1 wire, a nickel-chromium wire, or the like can be used. The insulating film is provided so as to cover the circumference of the conducting wire. If the heating wire 31 is provided with an insulating film, the insulating film preferably has a melting point of 230° C. or higher. This is because the melting point of the insulation film is preferably set to a temperature at which the thermoplastic resin in this embodiment does not melt (for example, in the case of polyethylene, the heating wire is heated up to 220 degrees). be. The insulating film can be formed of, for example, a fluorine-based resin or an imide-based resin, but is more preferably formed of a polyimide-based resin. For example, the thickness of the conducting wire may be set to 0.1 mm or more and 10 mm or less. Also, the heating wire 31 generates heat at about 180 to 230 degrees.

Arrangement of the heating wire 31 in the socket heat generating portions 3 and 4 will be described. The socket heat generating portions 3 and 4 are provided symmetrically with respect to the center of the tubular portion 21 .

At the joint receptacle portion 23, the heating wire 31 is wound 8 times so as to be in contact therewith. At the joint receptacle portion 24, the heating wire 31 is wound 8 times so as to be in contact therewith.

A predetermined space L0 is provided in the axial direction A between the heating wire portion 31a of the socket heating portion 3 and the heating wire portion 31b of the socket heating portion 4, as shown in FIG.

In order to heat the socket heat generating parts 3 and 4, the clearance W1 (see FIG. 3) between the inner surface 21a of the joint socket part 23 and the outer surface of the resin pipe 11 and the inner surface 21a of the joint socket part 24 and the resin pipe 11 are required. The clearance W1 between the outer surface of the pipe 12 is filled with molten resin, and the joint socket portion 23 and the resin pipe 11, and the joint socket portion 24 and the resin pipe 12 are fused.

(Connector mounting portion 5)
As shown in FIGS. 2 and 4, the connector attachment portion 5 has two pins 51b and 51c (an example of a pair of first terminals). The two pins 51 b and 51 c are provided so as to protrude radially outward from the outer surface 21 d of the cylindrical portion 21 . One pin 51b of the two pins 51b and 51c is arranged near the end 21b of the cylindrical portion 21, and the other pin 51c is arranged near the end 21c, as shown in FIG.

The end of the heating wire portion 31a of the heating wire 31 on the side of the end 21b is connected to the pin 51b. The end of the heating wire portion 31b of the heating wire 31 on the side of the end 21c is connected to the pin 51c. By attaching a connector of an electric fusion device to the pin 51b and the pin 51c and applying a current, the socket heating portions 3 and 4 can generate heat.

<Jig 200>
Next, the jig 200 used for the connection method of the embodiment according to the present disclosure will be described. The resin pipe 11 , the electric fusion joint 1 and the resin pipe 12 are arranged on the jig 200 . FIG. 5 is a diagram showing the jig 200. As shown in FIG. FIG. 6 is a diagram showing a state in which the resin pipe 11, the electric fusion joint 1, and the resin pipe 12 are attached to the jig 200. FIG. FIG. 7 is a side view of FIG. 6;

The jig 200 includes a first clamp portion 210 , a second clamp portion 220 , a shaft portion 230 , a pressing portion 240 , a restricting portion 250 and a base 260 .

(pedestal 260)
The pedestal 260 is a plate-like member. The pedestal 260 supports the first clamp portion 210, the second clamp portion 220, the shaft portion 230, the pressing portion 240, and the restricting portion 250 arranged on the upper surface side.

(First clamp part 210)
The first clamp part 210 clamps and fixes the resin pipe 11 . The first clamp portion 210 has a lower clamp portion 211 , an upper clamp portion 212 , a hinge portion 213 , a fastening portion 214 and a bearing portion 215 . The lower clamp part 211 is a member having a semicircular concave portion 211a formed on its upper surface. In the present embodiment, the lower clamping part 211 is a substantially rectangular parallelepiped member having a semicircular concave portion formed on its upper surface.

The bearing portion 215 is provided on the lower clamp portion 211 . The bearing portion 215 is inserted into a through hole formed in the lower clamp portion 211 . The bearing portion 215 is arranged below the recess 211a. A shaft portion 230 , which will be described later, is inserted inside the bearing portion 215 . The axial direction of the bearing portion 215 is arranged parallel to the central axis of the recess 211a. Thereby, the first clamp part 210 can move along the shaft part 230 . The axial direction of the bearing portion 215 is parallel to the axial direction A when the resin pipe 11, the resin pipe 12 and the electric fusion joint 1 are arranged on the jig.

The upper clamp part 212 is a member in which a semicircular recessed part 212a is formed. In this embodiment, the upper clamp part 212 is a substantially rectangular parallelepiped member having a semicircular concave portion 212a formed on one predetermined surface.
The upper clamping part 212 and the lower clamping part 211 can clamp the outer periphery of the resin pipe 11 with recesses 212a and 211a formed therein. The center axes of the recess 212a and the recess 211a generally coincide with each other when the resin pipe 11 is sandwiched between them. Further, in the state where the resin pipe 11 is sandwiched, the center axis coincides with the axial direction A described above.

The hinge portion 213 rotatably connects the ends of the lower clamp portion 211 and the upper clamp portion 212 . The upper clamp portion 212 is configured to be rotatable with respect to the lower clamp portion 211 about the hinge portion 213 . The upper clamp portion 212 is attached to the lower clamp portion 211 via the hinge portion 213 so that the concave portion 212a of the upper clamp portion 212 faces the concave portion 211a of the lower clamp portion 211 when the upper clamp portion 212 rotates about the hinge portion 213. there is

The resin pipe 11 is arranged along the concave portion 211 a of the lower clamp portion 211 with the hinge portion 213 as the center and the gap between the lower clamp portion 211 and the upper clamp portion 212 opened. After that, the upper clamp portion 212 rotates about the hinge portion 213, and the resin pipe 11 is arranged so as to be fitted in the concave portion 212a.

The fastening portion 214 is a so-called snap lock. The fastening portion 214 has a lock body 214a and a projection 214b. The fastening portion 214 is provided on the side opposite to the hinge portion 213 with the concave portions 211 a and 212 a of the lower clamp portion 211 and the upper clamp portion 212 interposed therebetween. The lock body 214 a is arranged on the side surface of the lower clamp portion 211 , and the projection 214 b is arranged on the side surface of the upper clamp portion 212 . The lock body 214a has a lever 214c and an annular portion 214d. With the upper clamping part 212 rotated above the lower clamping part 211, the upper clamping part 212 is attached to the lower clamping part 211 by hooking the annular part 214d on the protrusion 214b and tilting the lever 214c downward. can be fastened in the closed state.

(Second clamp part 220)
The second clamp part 220 clamps and fixes the resin pipe 12 . The second clamp part 220 fixes the resin pipe 12 so that the central axis of the resin pipe 12 coincides with the central axis of the resin pipe 11 .

The second clamp part 220 has a lower clamp part 221 , an upper clamp part 222 , a hinge part 223 and a fastening part 224 . The lower clamp part 221 is a member having a semicircular concave portion 221a formed on its upper surface. In this embodiment, the lower clamping part 221 is a substantially rectangular parallelepiped member having a semicircular concave portion formed on the upper surface thereof. The lower clamp part 211 is fixed to the pedestal 260 via a bracket 270 .

The upper clamp part 222 is a member in which a semicircular recessed part 222a is formed. In this embodiment, the upper clamp part 222 is a substantially rectangular parallelepiped member having a semicircular concave portion 222a formed on one predetermined surface.
The upper clamping part 222 and the lower clamping part 221 can clamp the outer circumference of the resin pipe 12 with recesses 222a and 221a formed therein. In a state in which the resin pipe 12 is sandwiched, the central axes of the recess 222a and the recess 221a are substantially aligned. In addition, in a state in which the resin pipe 12 is sandwiched, this central axis coincides with the axial direction A described above.

The hinge portion 223 rotatably connects the ends of the lower clamp portion 221 and the upper clamp portion 222 . The upper clamp portion 222 is configured to be rotatable with respect to the lower clamp portion 221 about the hinge portion 223 . The upper clamp part 222 is attached to the lower clamp part 221 via the hinge part 223 so that the concave part 222a faces the concave part 221a of the lower clamp part 221 when the upper clamp part 222 rotates about the hinge part 223. there is

The resin pipe 12 is arranged along the concave portion 221 a of the lower clamp portion 221 with the hinge portion 223 as the center and the gap between the lower clamp portion 221 and the upper clamp portion 222 opened. After that, the upper clamp portion 222 rotates about the hinge portion 223, and the resin pipe 12 is arranged so as to be fitted in the concave portion 222a.

The fastening portion 224 is a so-called snap lock. The fastening portion 224 has a lock body 224a and a projection 224b. The fastening portion 224 is provided on the side opposite to the hinge portion 223 with the concave portions 221 a and 222 a of the lower clamp portion 221 and the upper clamp portion 222 interposed therebetween. The lock body 224 a is arranged on the side surface of the lower clamping portion 221 , and the protrusion 224 b is arranged on the side surface of the upper clamping portion 222 . The lock body 224a has a lever 224c and an annular portion 224d. With the upper clamp part 222 rotated above the lower clamp part 221, the upper clamp part 222 is clamped against the lower clamp part 221 by hooking the annular part 224d on the projection 224b and tilting the lever 224c downward. can be fastened in the closed state.

With the resin pipe 11 and the resin pipe 12 inserted into the electric fusion joint 1 , the resin pipe 11 is clamped by the first clamping part 210 and the resin pipe 12 is clamped by the second clamping part 220 . A tube 11, a resin tube 12 and an electrofusion joint 1 can be arranged.

(Shaft portion 230)
Axial portion 230 is supported by pedestal 260 . Axial portion 230 is arranged parallel to the central axis of recess 211 a and recess 212 a of first clamp portion 210 . The shaft portion 230 is arranged parallel to the central axis of the recesses 221 a and 222 a of the second clamp portion 220 . The shaft portion 230 is arranged parallel to the central axes of the resin pipe 11 fixed to the first clamp portion 210 and the resin pipe 12 fixed to the second clamp portion 220 . The shaft portion 230 is arranged along the axial direction A described above.

The shaft portion 230 extends from the second clamp portion 220 toward the first clamp portion 210 side. The first clamp part 210 is attached to the shaft part 230 so as to be movable along the shaft part 230 . The shaft portion 230 is arranged from the lower clamp portion 221 to the lower clamp portion 211 . A bearing portion 215 is arranged below the concave portion 211 a of the lower clamp portion 211 of the first clamp portion 210 , and the shaft portion 230 is inserted through the bearing portion 215 .

(Pressing portion 240)
The pressing portion 240 presses the first clamp portion 210 toward the second clamp portion 220 along the shaft portion 230 . The pressing portion 240 has a spring 241 and a nut 242 .

A spring 241 is arranged around the shaft portion 230 of the first clamp portion 210 opposite to the second clamp portion 220 .

The nut 242 is arranged on the shaft portion 230 of the spring 241 opposite to the first clamp portion 210 . A male thread is formed around the end of the shaft portion 230 opposite to the second clamp portion 220 , and is screwed with a female thread formed inside the nut 242 . Nut 242 is movable along shaft 230 by rotating it.

A spring 241 is arranged between the nut 242 and the first clamping part 210 . Since the nut 242 is screwed onto the shaft portion 230 and fixed in position on the shaft portion 230 , a load directed toward the second clamp portion 220 is applied to the first clamp portion 210 by the spring 241 . The load can be set, for example, in the range of 1-50 kgf, more preferably in the range of 3-20 kgf. Further, when the nut 242 is rotated and brought close to the first clamp portion 210 with the resin pipes 11 and 12 and the electric fusion joint 1 arranged on the jig 200, the spring 241 is compressed. load can be increased. On the other hand, when the nut 242 is rotated to move away from the first clamp portion 210, the spring 241 expands, so the load applied to the first clamp portion 210 can be reduced.

As shown in FIG. 7 , the resin pipe 11 is clamped by applying a load to the first clamp portion 210 with the pressing portion 240 in a state where the resin pipe 11 , the resin pipe 12 and the electric fusion joint 1 are arranged on the jig 200 . A load is applied to the pipe end 11 a of the resin pipe 12 and the pipe end 12 a of the resin pipe 12 so as to be pressed against the stopper portion 22 .

(regulator 250)
The restricting portion 250 restricts the first clamping portion 210 from excessively moving toward the second clamping portion 220 by the pressing portion 240 .

The restricting portion 250 is arranged between the first clamping portion 210 and the second clamping portion 220 .

The restricting portion 250 has a fixing portion 251 and a contact portion 252 . The fixed part 251 is fixed to the pedestal 260 . The contact portion 252 is a portion that extends upward from the fixed portion 251 and is arranged around the shaft portion 230 . Since the bearing portion 215 of the first clamp portion 210 contacts the contact portion 252 , further movement of the first clamp portion 210 toward the second clamp portion 220 can be restricted.

<Connection method>
Next, a connection method according to an embodiment of the present invention will be described. FIG. 8 is a flow chart for explaining the connection method of this embodiment.

First, in step S1, the pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 are heated by heaters. As shown in FIG. 9A, the pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 are pressed against the heater 300 to heat the pipe ends 11a and 12a. The temperature of the heating wire during heating may be any temperature that can melt the cylindrical portion 21, and in the case of polyolefin, it is preferably 220 degrees or less.

Next, in step S2, as shown in FIG. 9B, the pipe end 11a of the resin pipe 11 is inserted into the joint receptacle 23 of the electric fusion joint 1 (in the direction of arrow A1), and the resin pipe 12 is is inserted into the joint receptacle portion 24 of the electric fusion joint 1 (in the direction of arrow A2).

Next, in step S3, the resin pipe 11, the electric fusion joint 1 and the resin pipe 12 are attached to the jig 200 as shown in FIG. A load directed toward the second clamp portion 220 is applied to the first clamp portion 210 by the pressing portion 240 of the jig 200, and as shown in FIG. can be abutted while pressurizing the tube ends 12a. As a result, a bead R in which the resin rises is formed on the inner and outer peripheries of the pipe end 11a and the pipe end 12a (see dotted line P1 in FIG. 10(a)). In this manner, the resin pipe 11 and the resin pipe 12 are butt-fused inside the electric fusion joint 1 .

In step S3, the pipe end 11a of the melted resin pipe 11 and the pipe end 12a of the melted resin pipe 12 are pressed against each other. By moving toward the clamp part 220 side, the magnitude of the load applied to the first clamp part 210 by the spring 241 can be maintained. Thus, the pressure applied by the pressing portion 240 can be adjusted. For example, pressurization may be applied for a predetermined period of time, and then the nut 242 may be adjusted to prevent pressurization.

Next, in step S4, the connector 81 of the electric fusion device is attached to the two pins 51b and 51c of the connector attachment portion 5, and the socket heat generating portions 3 and 4 are energized for a predetermined time. The temperature of the heating wire during energization may be any temperature that can melt the cylindrical portion 21, and is preferably 220° C. or less in the case of polyolefin. Note that step S4 is preferably performed after the resin pipes 11 and 12 fused in step S3 are cooled.

The socket heat generating parts 3 and 4 generate heat due to the energization, and as shown in FIG. reference).

Next, in step S5, the energization of the socket heat generating parts 3 and 4 is terminated, and the joint socket parts 23 and 24 are cooled to complete the fusion between the inner surfaces 21a of the joint socket parts 23 and 24 and the outer peripheral surfaces of the resin pipes 11 and 12. .

<Use of piping structure 100 for ultrapure water>
The piping structure 100 of the embodiment according to the present disclosure can be used for transporting ultrapure water, for example. Specifically, the ultrapure water piping structure 100 of the embodiment according to the present disclosure includes piping in the ultrapure water production apparatus, piping for transporting ultrapure water from the ultrapure water production apparatus to the point of use, and It can be used as a pipe for returning ultrapure water from the point of use, or the like.

Ultrapure water is water of extremely high purity, and is suitably used for cleaning electronic devices such as semiconductor devices. Although there are many indices for expressing the grade of ultrapure water, in this embodiment, the ultrapure water has an electrical resistivity of 18.2 MΩ·cm or more and a TOC of 50 ppb or less.

The piping structure 100 of the embodiment according to the present disclosure is used for nuclear power generation water piping, or in the manufacturing process of pharmaceuticals, semiconductor elements or liquid crystals, more preferably in the manufacturing process of semiconductor elements, where the required water quality for ultrapure water is particularly strict. It is preferably an ultrapure water transport pipe used in a wet treatment process such as cleaning. The semiconductor element is preferably one having a higher degree of integration, and more specifically, it is more preferably used in the manufacturing process of a semiconductor element having a minimum line width of 65 nm or less. Standards relating to the quality of ultrapure water used in semiconductor manufacturing include, for example, SEMI F75.

Moreover, since the piping structure 100 of the embodiment according to the present disclosure has a polyethylene-based resin layer, it is excellent in workability. For example, it is possible to easily perform a fusion process such as EF (Electrical Fusion) bonding at a relatively low temperature.

<Features>
The connection method according to the present embodiment includes step S1 (an example of a tube end heating step), step S3 (an example of a first fusion step), and step S4 (an example of a second fusion step, a third fusion step). An example of) and. A step S1 heats the pipe end 11a of the resin pipe 11 containing thermoplastic resin (an example of a first pipe) and the pipe end 12a of the resin pipe 12 containing a thermoplastic resin (an example of a second pipe). In step S3, after step S1, the pipe end 11a of the resin pipe 11 inserted into the joint receptacle portion 23 (an example of the first joint receptacle portion) provided at one of both ends of the electric fusion joint 1 is Then, the pipe end 12a of the resin pipe 12 inserted into the joint socket portion 24 (an example of the second joint socket portion) provided on the other side is brought into contact with the inside of the electric fusion joint 1 to 11a and 12a are fused together. In step S4, the joint socket portion 23 and the resin pipe 11 are fused by energizing the socket heat generating portion 3 (an example of the first socket heat generating portion) that is arranged in the joint socket portion 23 and includes the heating wire 31. Then, the socket heating portion 4 (an example of the second socket heating portion) arranged in the joint socket portion 24 and including the heating wire 31 is energized to melt the second joint socket portion and the resin pipe 12 . to wear

A piping structure 100 according to the present embodiment includes a resin pipe 11 (an example of a first pipe), a resin pipe 12 (an example of a second pipe), and an electric fusion joint 1 . The resin pipe 11 contains thermoplastic resin. The resin pipe 12 contains thermoplastic resin. The electric fusion joint 1 includes a joint receptacle portion 23 (an example of a first joint receptacle portion) into which the resin pipe 11 is inserted, and a joint receptacle portion 24 (an example of a second joint receptacle portion) into which the resin pipe 12 is inserted. example), a socket heat generating portion 3 (an example of a first socket heat generating portion) arranged in the joint socket portion 23 and including the heating wire 31, and a socket portion 3 arranged in the joint socket portion 24 and including the heating wire 31 and a receptacle heat-generating part 4 (an example of a second receptacle heat-generating part). The pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 are butted against each other inside the electric fusion joint 1 and fused.

After the pipe ends of the resin pipe 11 and the resin pipe 12 are fused together in this manner, the outer surface of the resin pipe 12 and the outer surface of the resin pipe 11 and the inner surface 21a of the joint receptacle portion 23 of the electric fusion joint 1 and the outer surface of the resin pipe 12 are separated. and the inner surface 21a of the joint receptacle 24 are fused together, air is not trapped, and the height of the resin rising inside can be made uniform. FIG. 11 is a diagram showing a state in which the height of the resin rising inside is uniform. FIG. 11 is a diagram of the piping structure 100 viewed from the resin pipe 11 side. As shown in the figure, a bead R is formed in which the resin is uniformly raised along the circumferential direction C. As shown in FIG.

Since the pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 are joined by butt fusion, the resin pipe 11 and the resin pipe 12 are joined together more easily than in the conventional case where the fusion is performed only by heating the electric heating wire. It is difficult to create a gap between them.

Also, the bead R can be reduced by performing butt fusion.

(Embodiment 2)
Next, the piping structure 400 in Embodiment 2 according to the present disclosure will be described. A piping structure 400 according to the second embodiment has an electric fusion joint 500 having a different configuration from that of the first embodiment. In the description of the second embodiment, the same reference numerals are given to the same configurations as in the first embodiment, and the description thereof will be omitted.

FIG. 12 is a cross-sectional view showing the configuration of the electrofusion joint 500 of the second embodiment.

Unlike the electrical fusion joint 1 of the first embodiment, the electrical fusion joint 500 of the second embodiment includes a stopper portion 22 that restricts the inserted resin pipes 11 and 12 . The stopper portion 22 is arranged between the joint socket portion 23 and the joint socket portion 24 .

As shown in FIG. 12 , the electric fusion joint 1 has a body portion 2 , socket heat generating portions 3 and 4 , a stopper heat generating portion 7 , a connector mounting portion 5 and a connector mounting portion 6 .

(Body part 2)
The body portion 2 is made of thermoplastic resin, and has a tubular portion 21 and a stopper portion 22 as shown in FIG. 12 . The tubular portion 21 is tubular and has a joint socket portion 23 , a joint socket portion 24 , and a connecting portion 25 . The resin pipe 11 is inserted inside the joint receiving portion 23 . The resin pipe 12 is inserted inside the joint receiving portion 24 .

The thermoplastic resin used in the main body 2 is not particularly limited, but preferably has a melting point of less than 230°C.

FIG. 13 is a cross-sectional configuration diagram showing a state in which the resin pipe 11 is inserted inside the joint receptacle portion 23 of the electric fusion joint 500 and the resin pipe 12 is inserted inside the joint receptacle portion 24 .

The inner diameter of the joint receiving portion 23 is formed to be equal to or larger than the outer diameter of the resin pipe 11 . Also, the inner diameter of the joint receiving portion 24 is formed to be equal to or larger than the outer diameter of the resin pipe 12 .

As shown in FIG. 12 , the connecting portion 25 continues to the joint socket portion 23 and the joint socket portion 24 and connects the joint socket portion 23 and the joint socket portion 24 . The connecting portion 25 is a portion that connects the joint socket portion 23 and the joint socket portion 24, and a stopper portion 22, which will be described later, is provided inside in the radial direction B. As shown in FIG. A connecting portion 25 is arranged between the side opposite to the end 21b of the joint socket portion 23 and the opposite side to the end 21c of the joint socket portion 24 .

(Stopper portion 22)
The stopper portion 22 is an annular portion. The stopper portion 22 is a ridge along the circumferential direction C on the inner surface 21a of the cylindrical portion 21 and is formed over the entire circumference. The stopper portion 22 also contains a thermoplastic resin, and is preferably made of the same thermoplastic resin as the thermoplastic resin used in the tubular portion 21 .

As shown in FIG. 12, the stopper portion 22 is formed to protrude radially inward from the inner surface 21a of the tubular portion 21 . Further, the stopper portion 22 is arranged inside the connecting portion 25 of the cylindrical portion 21 in the radial direction B. As shown in FIG. The stopper portion 22 may be formed as one member with the tubular portion 21 or may be formed as a separate member from the tubular portion 21 .

The stopper portion 22 has a first side surface 22a, a second side surface 22b, and a peripheral surface 22c. The peripheral surface 22 c is a radially inner end surface of the stopper portion 22 .

The first side surface 22a is formed substantially perpendicular to the axial direction A from the inner surface 21a of the cylindrical portion 21 toward the inside in the radial direction B. As shown in FIG.

The second side surface 22b is formed substantially perpendicular to the axial direction A from the inner surface 21a of the cylindrical portion 21 toward the inside in the radial direction B. As shown in FIG.

The peripheral surface 22c connects the radially inner end of the first side surface 22a and the radially inner end of the second side surface 22b. The peripheral surface 22 c is formed substantially parallel to the inner surface 21 a of the cylindrical portion 21 .

When the resin pipe 11 is inserted into the joint receptacle portion 23, the stopper portion 22 regulates the insertion position of the pipe end 11a, as shown in FIG. 13, the pipe end 11a contacts the first side surface 22a of the stopper portion 22 and the stopper portion 22 directly regulates the insertion position of the pipe end 11a. This includes the case where the stopper portion 22 indirectly restricts the contact with the heating wire 41 (described later) of the heat generating portion 7 .

When the resin pipe 12 is inserted into the joint receptacle portion 24, the stopper portion 22 regulates the insertion position of the pipe end 12a, as shown in FIG. 13, the pipe end 12a contacts the second side surface 22b of the stopper portion 22 and the stopper portion 22 directly regulates the insertion position of the pipe end 12a. This includes the case where the stopper portion 22 indirectly restricts the contact with the heating wire 41 (described later) of the heat generating portion 7 .

In addition, in the present embodiment, crevices are suppressed from occurring between the pipe end 11a and the first side surface 22a and between the pipe end 12a and the second side surface 22b (see position V).

(Stopper heating portion 7)
The stopper heat generating portion 7 is provided in the stopper portion 22 . The stopper heat generating portion 7 has a heating wire 41 . The heating wire 41 is provided on the stopper portion 22 so as to be wound in the circumferential direction C along the axial direction A. As shown in FIG. In the present embodiment, the heating wire 41 is wound around the stopper portion 22, for example, four turns, but the number of turns is not limited to four, and may be five or more or three or less. may In the stopper heat generating portion 7 of the present embodiment, all the adjacent heating wires 41 are in contact with each other, but a gap may be provided between all or part of the adjacent heating wires 41 .

The heating wire 41 can be made of the same material and structure as the heating wire 31 . The heating wire 41 is heated at about 180 to 230 degrees.

As shown in FIG. 12, a predetermined gap L1 is provided along the axial direction A between the stopper heat generating portion 7 and the heating wire portion 31a closest to the stopper heat generating portion 7. As shown in FIG. Further, along the axial direction A, a predetermined interval L1 is provided between the stopper heat generating portion 7 and the heating wire portion 31b closest to the stopper heat generating portion 7. As shown in FIG. In the present embodiment, the socket heat-generating portion 3 and the socket heat-generating portion 4 are provided bilaterally symmetrically, but they do not have to be bilaterally symmetrical.

The diameter of the heating wire 41 wound in the stopper heat generating portion 7 is set smaller than the diameter of the heating wire 31 wound in the socket heat generating portions 3 and 4 .

Further, the diameter of the heating wire 41 wound in the stopper heat generating portion 7 is set so that the position of the heating wire 41 is set to fit between the wall thicknesses of the resin pipes 11 and 12 into which it is inserted.

In order to heat the stopper heat-generating portion 7, the first side surface 22a of the stopper portion 22 and the pipe end 11a of the resin pipe 11 (see position V in FIG. 13), the second side surface 22b of the stopper portion 22 and the resin pipe 12 and the pipe end 12a (see position V in FIG. 13) is filled with molten resin, and the stopper portion 22 and the resin pipe 11 and the stopper portion 22 and the resin pipe 12 are fused.

(Connector attachment portion 6)
As shown in FIG. 12, the connector attachment portion 6 has two pins 61b and 61c (an example of a pair of second terminals). The two pins 61b and 61c are provided so as to protrude radially outward from the outer surface 21d of the tubular portion 21 . The two pins 61b and 61c are arranged side by side along the axial direction A near the center of the tubular portion 21 .

One pin 61b of the two pins 61b and 61c is arranged on the end 21b side, and the other pin 61c is arranged on the end 21c side.

FIG. 14 is a schematic diagram showing the connection relationship between the connector mounting portions 5 and 6 and the heating wires 31 and 41. As shown in FIG.

As shown in FIG. 14, one end of the heating wire 41 is connected to the pin 61b, and the other end of the heating wire 41 is connected to the pin 61c. The stopper heat generating portion 7 can generate heat by attaching a connector of an electric fusion device to the pins 61b and 61c and energizing them.

Further, as shown in FIG. 14, the socket heat generating part 3 has a heating wire 31 wound eight times, and the socket heating part 4 has a heating wire 31 wound eight times. ing. The socket heat-generating part 3 and the socket heat-generating part 4 are connected by one heating wire 31, and both ends thereof are connected to pins 51b and 51c. A heating wire portion 31 c of the heating wire 31 that connects between a heating wire portion 31 a forming the socket heat generating portion 3 and a heating wire portion 31 b forming the socket heat generating portion 4 is embedded in the connecting portion 25 . . In the second embodiment, the heating wire portion 31c is embedded in the connecting portion 25 along the axial direction A instead of being wound in the circumferential direction as in the first embodiment. , and embedded in the connecting portion 25 .

In this way, since the connector mounting portion 5 for generating heat in the socket heat generating portions 3 and 4 and the connector mounting portion 6 for generating heat in the stopper heat generating portion 7 are provided separately, the socket heat generating portion 3 and the timing of energizing the stopper heating portion 7 can be changed.

<Connection method>
Next, a connection method according to an embodiment of the present disclosure will be described. FIG. 15 is a flowchart for explaining the connection method of this embodiment.

First, in step S10, the pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 are heated by heaters. As shown in FIG. 16A, the pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 are pressed against the heater 300 to heat the pipe ends 11a and 12a. The temperature of the heating wire during heating may be any temperature that can melt the cylindrical portion 21, and in the case of polyolefin, it is preferably 220 degrees or less.

Next, in step S11, as shown in FIG. 16(b), the connector 81 of the electrofusion device is attached to the two pins 61b and 61c of the connector attachment portion 6, and energization of the stopper heat generating portion 7 is started. be done. Thereby, the stopper portion 22 is heated (see dotted line P3). Steps S10 and S11 may be performed at the same time.

After a predetermined period of time has elapsed, in step S12, power supply to the stopper heat generating portion 7 is stopped.

Next, in step S13, as shown in FIG. 17A, the resin pipe 11 is inserted from the heated pipe end 11a side into the socket heating portion 3 until it is regulated by the stopper portion 22, and the heated pipe end 12a is The resin pipe 12 is inserted from the side into the socket heating portion 4 until it is regulated by the stopper portion 22 . By warming the stopper portion 22 in step S11, it is possible to suppress the temperature drop of the tube ends 11a and 12a. Moreover, step S13 is preferably performed as soon as possible after the completion of energizing the stopper heat generating portion 7 in step S12.

Next, in step S14, the resin pipe 11, the electric fusion joint 500 and the resin pipe 12 are attached to the jig 200 described in the first embodiment.

As a result, as shown in FIG. 17B, the pipe end 11a of the resin pipe 11 is pressed against the first side surface 22a of the stopper portion 22, and the first side surface 22a of the stopper portion 22 and the pipe end 11a of the resin pipe 11 are separated. The pipe end 12a of the resin pipe 12 is pressed against the second side face 22b of the stopper portion 22, and the second side face 22b of the stopper portion 22 and the pipe end 12a of the resin pipe 12 are fused. In step S14, since the pipe end 11a of the melted resin pipe 11 and the pipe end 12a of the melted resin pipe 12 are pressed against the melted stopper portion 22, the pressure of the pressing portion 240 gradually decreases. By moving the nut 242 toward the second clamp portion 220 side, the magnitude of the load applied to the first clamp portion 210 by the spring 241 can be maintained. Thus, the pressure applied by the pressing portion 240 can be adjusted. For example, pressurization may be applied for a predetermined period of time, and then the nut 242 may be adjusted to prevent pressurization.

Next, in step S15, as shown in FIG. 18, the connector 81 of the electric fusion device is attached to the two pins 51b and 51c of the connector attachment portion 5, and the electricity is supplied for a predetermined time. The temperature of the heating wire during energization may be any temperature that can melt the cylindrical portion 21, and is preferably 220° C. or less in the case of polyolefin. Step S15 is preferably performed after the resin pipes 11 and 12 fused in step S14 are cooled.

This energization heats the socket heat generating parts 3 and 4, melting the inner surfaces 21a of the joint socket parts 23 and 24 and the outer peripheral surfaces of the resin pipes 11 and 12 (see dotted line P2).

Next, in step S16, the energization of the socket heat generating parts 3 and 4 is terminated, and the joint socket parts 23 and 24 are cooled to complete the fusion between the inner surfaces 21a of the joint socket parts 23 and 24 and the outer peripheral surfaces of the resin pipes 11 and 12. .

Note that the piping structure 400 of the second embodiment can be used for transporting ultrapure water, as in the case of the first embodiment.

<Features>
The connection method according to the second embodiment of the present disclosure includes step S10 (an example of a pipe end heating step), step S11 (an example of a stopper heating step), step S14 (an example of a first fusion step), and steps and S15 (an example of the second fusion step and the third fusion step). A step S10 heats the pipe end 11a of the resin pipe 11 containing the thermoplastic resin (an example of the first pipe) and the pipe end 12a of the resin pipe 12 containing the thermoplastic resin (an example of the second pipe). In step S11, the stopper portion 22 is provided on the inner surface of the cylindrical portion 21 of the electric fusion joint 500 so as to protrude inward, and the stopper heat generating portion 7 including the heating wire 41 is energized to heat it. In step S14, after step S11, the pipe end 11a of the resin pipe 11 inserted inside the joint socket portion 23 (an example of the first joint socket portion) provided at one of both ends of the cylindrical portion 21 and , and the pipe end 12 a of the resin pipe 12 inserted into the joint socket portion 24 (an example of the second joint socket portion) provided on the other side are fused to the stopper portion 22 . A step S15 energizes the socket heating portion 3 (an example of the first socket heating portion) arranged in the joint socket portion 23 and including the heating wire 31 to fuse the socket heating portion 3 and the resin pipe 12 together. The socket heating portion 4 (an example of the second joint socket portion) is placed in the socket heating portion 4 (an example of the second joint socket portion), and the socket heating portion 4 (an example of the second socket heating portion) including the heating wire 31 is energized to The heat generating part 4 and the resin pipe 12 are fused.

After the pipe ends 11a and 12a of the resin pipe 11 and the resin pipe 12 are fused to the stopper portion 22 in this manner, the outer surface of the resin pipe 12 and the outer surface of the resin pipe 11 and the inner surface 21a of the joint receptacle portion 23 are separated. and the inner surface 21a of the joint receptacle 24 are fused together, air is not trapped, and the height of the resin rising inside can be made uniform.

Not only the stopper portion 22 is heated, but also the pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 are heated and fused to the stopper portion 22, so that heating of the heating wire is sufficient as in the conventional art. A gap is less likely to occur between the resin pipes 11 and 12 than by fusing.

Also, the bead R can be reduced by performing butt fusion.

In the connection method according to the second embodiment of the present disclosure, step S14 (an example of the first fusion bonding step) is performed after step S12 of ending the energization of the stopper heat generating portion 7 in step S11 (an example of the stopper heating step). conduct.

In this way, after the heating of the stopper portion 22 is completed, the pipe end 11a of the heated resin pipe 11 and the pipe end 12a of the resin pipe 12 are fused to the stopper portion 22, thereby suppressing the occurrence of gaps. can be done.

<Other embodiments>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the invention.

(A)
In the second embodiment, the pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 are pressed against the stopper portion 22 after the energization of the stopper heat generating portion 7 is completed. Alternatively, the pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 may be pressed against the stopper portion 22 while the stopper heat generating portion 7 is energized.

(B)
In the second embodiment, the outer diameter of the stopper portion 22 is circular when viewed along the axial direction A, but it is not limited to a circle and may be polygonal.

(C)
In Embodiments 1 and 2 above, all the heating wires 31 are wound so that the adjacent portions of the heat generating sockets 3 and 4 are in contact with each other. Also, as in Comparative Example 1 to be described later, the portions of the heating wire adjacent to each other may be in contact with each other with a predetermined interval therebetween, or the socket heat generating portions 3 and 4 may be in contact with each other at intervals. The numbers can be different.

(D)
In the above-described embodiment, the socket heat-generating portion 3 and the socket heat-generating portion 4 are provided symmetrically with the stopper portion 22 interposed therebetween, but this need not be the case. For example, the heating wire 31 may be wound 7 turns around the joint receiving portion 23 on one side and the heating wire 31 may be wound around 8 turns around the joint receiving portion 24 on the other side of the stopper portion 22 .

(E)
In the above-described embodiment, the flow paths of the electrofusion joint 1 are all formed in a straight line, but an elbow joint having a curved flow path may also be used.

(F)
In the second embodiment, since the same heating wire 31 of the socket heating portion 3 and the heating wire 41 of the stopper heating portion 7 are used, all the heating wires 31, 41 are provided with an insulating coating. However, it does not have to be limited to this. However, it is preferable that at least the heating wire 41 is provided with an insulating coating. This is because the heating wires 41 are likely to come into contact with each other due to the pressure applied by the resin pipes 11 and 12 .

(G)
In the above embodiment, the resin pipes 11 and 12 are used as an example of pipes, but the pipes are not limited to this, and pipes using resin such as metal-reinforced composite pipes having metal-reinforced layers may be used.

(H)
In Embodiments 1 and 2 above, the socket heat-generating portion 3 and the socket heat-generating portion 4 are heated at the same time. In this case, either one of the socket heat-generating portion 3 and the socket heat-generating portion 4 may be heated before the other is heated.

(I)
In Embodiments 1 and 2 described above, the spring 241 and the nut 242 are used as the pressing portion that applies a load to the first clamp portion 210, but the present invention is not limited to this. There may be. Further, the pressing of the tube ends 11a and 12a against the stopper portion 22 may be due to either the addition of a load to the first clamp portion 210 or the amount of movement thereof.

Further, when the load is applied using a motor or cylinder, it may be controlled in conjunction with the electric fusion device. For example, according to a preset program, the motor and cylinder may be controlled according to the elapse of the heating time by the electro-fusion apparatus so that a predetermined load or more is maintained.

(Example)
Embodiments 1 and 2 described above will be described in detail below using examples.

(Example 1)
In Example 1, resin pipes 11 and 12 were joined using the electric fusion joint 1 having the configuration shown in the first embodiment.

The material of the electrofusion joint 1 is olefin resin. The total length of the electrofusion joint 1 is 70-300 mm. The material of the resin pipes 11 and 12 is olefin resin. The heating wire 31 has an insulating film made of imide or amide-imide. The diameter of the heating wire 31 is 0.3-2.0 mm. The nominal diameter of the resin pipes 11 and 12 is 20-200A. The length of L0 is at least twice the diameter of the coated heating wire.

In Example 1, the electric fusion joint 1 and the resin pipes 11 and 12 were connected according to the flowchart of FIG. 8 described in the first embodiment.

The heating conditions for the pipe ends 11a and 12a of the resin pipes 11 and 12 shown in FIG. be. The pressure when the resin pipe 11 and the resin pipe 12 are fused together is 0.15 MPa×cross-sectional area. The conditions for heating the socket heat generating portions 3 and 4 are to apply a heating time and voltage exceeding 230°C.

(Comparative example 1)
In Comparative Example 1, resin pipes 11 and 12 were joined using an electric fusion joint 1100 having the configuration shown in FIG. Compared with the electric fusion joint 500 of Embodiment 2, the electric fusion joint 1100 shown in FIG. 31, the connector mounting portion 6 is not provided, and the winding configuration of the heating wire in the socket heat generating portion 1003 and the socket heat generating portion 1004 is different. In the receptacle heat generating portion 1003 of the electric fusion joint 1100 of Comparative Example 1, the heating wire 31 is wound two turns so that the heating wire 31 is in contact, and the heating wire 31 is in contact with the heating wire 31 with a predetermined interval L3 along the axial direction A. The winding is repeated twice. As shown in FIG. 19, for example, the heating wire 31 is wound eight turns in the socket heat generating portion 1003 . In the socket heat generating portion 1004, the heating wire 31 is wound two times so as to be in contact with the heating wire 31, and the heating wire 31 is repeatedly wound two times so as to be in contact with the heating wire 31 with a predetermined interval L3 along the axial direction A. ing. As shown in FIG. 19, for example, the heating wire 31 is wound eight turns in the socket heat generating portion 1004 .

In the electrofusion joint 1100, the stopper heat generating portion 1007 is formed by winding the heating wire 31 four times. A portion of the heating wire 31 that forms the socket heating portion 1003 is a heating wire portion 31a, a portion that forms the socket heating portion 1004 is a heating wire portion 31b, and a portion that forms the stopper heating portion 1007 is a heating wire portion 31d. Then, the heating wire portion 31a, the heating wire portion 31d, and the heating wire portion 31b are connected in this order.

The end of the heating wire portion 31a on the side of the end 21b is connected to the pin 51b, and the end of the heating wire portion 31b on the side of the end 21c is connected to the pin 51c. That is, by energizing the pins 51b and 51c, the stopper heat-generating portion 1007, the socket heat-generating portion 1003, and the socket heat-generating portion 1004 are heated at the same time.

A gap L2 is provided along the axial direction A between the stopper heat generating portion 1007 and two adjacent heating wire portions 31a arranged closest to the stopper heat generating portion 1007. A gap L2 is provided along the axial direction A between 1007 and two adjacent heating wire portions 31b arranged closest to the stopper heat generating portion 1007. As shown in FIG.

The material of the electrofusion joint 1100 is olefin resin. The total length of the electrofusion joint 1100 is 70-300 mm. The material of the resin pipes 11 and 12 is olefin resin. The heating wire 31 has an insulating film made of imide or amide-imide. The nominal diameter of the resin pipes 11 and 12 is 20-200A. The lengths of L2 and L3 are at least twice the diameter of the coated heating wire.

In Comparative Example 1, the structure in which the resin pipe 11 was inserted into the joint receptacle 23 of the electric fusion joint 1100 and the resin pipe 12 was inserted into the joint receptacle 24 was mounted on the jig 200 described above, and 0.15 The socket heat generating portions 1003 and 1004 and the stopper heat generating portion 1007 were heated by energizing the pins 51b and 51c while applying pressure of MPa×cross-sectional area.

The piping structures of Example 1 and Comparative Example 1 were cut, and it was visually confirmed whether or not a bead was ejected or a dent was generated.

The results are shown in (Table 1) below.

比較例１では、ビードの噴出若しくは窪みの発生が確認できたが、実施例１ではビードの噴出および窪みの発生が見られなかった。 (Table 1)

In Comparative Example 1, ejection of beads or occurrence of depressions could be confirmed, but in Example 1, ejection of beads and occurrence of depressions were not observed.

The ejection of the beads R or the occurrence of depressions in Comparative Example 1 will be described with reference to FIGS. 20(a) and 20(b). FIG. 20(a) is a partially enlarged view for explaining the fusion between the electrical fusion joint 1100 and the resin pipe 11 of Comparative Example 1. FIG. As shown in FIG. 20(a), in the portion (cold zone) between the stopper heat-generating portion 1007 and the socket heat-generating portion 1003, the clearance between the inner surface of the electric fusion joint 1100 and the outer surface of the resin pipe 11 ( (denoted by E) is air. When the fusion is started, fusion between the stopper heat-generating portion 1007 and the pipe end 11a of the resin pipe 11 (the fusion-bonded portion is indicated by Q2 in the figure) and the portion where the socket heat-generating portion 1003 is provided. Since fusion between the inner surface and the outer surface of the resin pipe 11 (the fused portion is indicated by Q1 in the figure) progresses simultaneously, the air in the clearance E is trapped between the fused portions Q1 and Q2. 20(b), the molten resin in the process of forming the bead R is pushed up, and the bead R is ejected. In addition, when air bubbles are mixed in the resin due to the expansion of air, and the mixed bubbles burst due to further expansion, the bead R is dented.

21A and 21B are diagrams showing an example of ejection and depression of the bead R. FIG. FIG. 21 is a view seen from the end 21b side. In FIG. 21 , R indicates the resin rising inward from the stopper portion 22 and the inner peripheral surface of the resin pipe 11 , and Q indicates the recess.

On the other hand, in Example 1, after the pipe end 11a of the resin pipe 11 and the pipe end 12a of the resin pipe 12 are joined by butt fusion, the outer surface of the resin pipe 11 and the joint receptacle portion 23 of the electric fusion joint 1 are joined. Since the inner surface 21a and the outer surface of the resin pipe 12 and the inner surface 21a of the joint receptacle 24 are fused, air is not trapped, and the resin (bead R) rises inward as shown in FIG. ) can be made uniform.

(Example 2)
In Example 2, the resin pipes 11 and 12 were joined using the electric fusion joint 500 having the configuration shown in the second embodiment.

The material of the electrofusion joint 500 is olefin resin. The total length of the electrofusion joint 500 is 70-300 mm. The material of the resin pipes 11 and 12 is olefin resin. The heating wire 31 has an insulating film made of imide or amide-imide. The nominal diameter of the resin pipes 11 and 12 is 20-200A. The length of L1 is at least twice the diameter of the coated heating wire.

In Example 2, the electric fusion joint 1 and the resin pipes 11 and 12 were connected according to the flowchart of FIG. 15 described in the second embodiment.

The conditions for heating the pipe ends 11a and 12a of the resin pipes 11 and 12 in FIG. The pressure when the resin pipe 11 and the resin pipe 12 are fused together is 0.15 MPa×cross-sectional area. The heating condition of the stopper heat generating portion 7 in FIG. 16(b) is
It is to apply a heating time and voltage that exceeds 230 degrees. The pressure applied to the electric fusion joint 500 of the resin pipes 11 and 12 in FIGS. 17(a) and 17(b) is 0.15 MPa×cross-sectional area. The conditions for heating the socket heat generating portions 3 and 4 in FIG. 18 are to apply a heating time and voltage exceeding 230 degrees.

The piping structure of Example 2 produced in this way was cut, and it was visually confirmed whether or not there was a bead ejection or a dent. The results of Example 2 are shown together with the results of Comparative Example 1 in Table 2 below.

実施例２では、樹脂管１１と樹脂管１２の管端１１ａ、１２ａをストッパ部２２と融着した後に、樹脂管１１の外面と継手受口部２３の内面２１ａの間と、樹脂管１２の外面と継手受口部２４の内面２１ａの間とが融着されるため、空気が閉じ込められず、内側に盛り上がる樹脂の高さを均一にすることができる。 (Table 2)

In Example 2, after the pipe ends 11a and 12a of the resin pipe 11 and the resin pipe 12 are fused to the stopper portion 22, a gap between the outer surface of the resin pipe 11 and the inner surface 21a of the joint receptacle portion 23 and between the resin pipe 12 Since the outer surface and the inner surface 21a of the joint receptacle 24 are fused together, air is not trapped, and the height of the resin rising inside can be made uniform.

Reference Signs List 1: electric fusion joint 3: socket heat-generating portion 4: socket heat-generating portion 11: resin pipe 11a: pipe end 12: resin pipe 12a: pipe end

Claims (5)

a tube end heating step of heating the tube ends of the first tube containing the thermoplastic resin and the tube ends of the second tube containing the thermoplastic resin;
After the pipe end heating step, the pipe end of the first pipe inserted inside the first joint receptacle part provided at one of both ends of the electric fusion joint and the second joint receptacle provided at the other end a first fusion step of bringing the pipe ends of the second pipe inserted into the mouth into contact with each other inside the electric fusion joint to fuse the pipe ends;
a second fusing step of energizing a first socket heating portion arranged in the first joint socket portion and including a heating wire to fuse the first joint socket portion and the first pipe;
a third fusing step of energizing a second socket heat-generating portion disposed in the second joint socket portion and including a heating wire to fuse the second joint socket portion and the second pipe; connection method. a tube end heating step of heating the tube ends of the first tube containing the thermoplastic resin and the tube ends of the second tube containing the thermoplastic resin;
a stopper heating step of energizing and heating a stopper heating portion including a heating wire arranged in a stopper portion provided so as to protrude inward from the inner surface of the cylindrical portion of the electric fusion joint;
After the pipe end heating step, the pipe end of the first pipe inserted into the inside of the first joint receptacle provided on one of both ends of the cylindrical portion and the second joint receptacle provided on the other end a first fusing step of fusing the pipe end of the second pipe inserted inside the mouth portion to the stopper portion;
a second fusing step of energizing a first socket heating portion arranged in the first joint socket portion and including a heating wire to fuse the first joint socket portion and the first pipe;
a third fusing step of energizing a second socket heat-generating portion disposed in the second joint socket portion and including a heating wire to fuse the second joint socket portion and the second pipe; connection method. performing the first fusion step after energization of the stopper heat generating portion in the stopper heating step is completed;
The connection method according to claim 2. The second fusing step and the third fusing step are performed simultaneously,
The connection method according to any one of claims 1 to 3. a first tube comprising a thermoplastic resin;
a second tube comprising a thermoplastic resin;
A first joint receiving portion into which the first pipe is inserted, a second joint receiving portion into which the second pipe is inserted, and a first receiving portion arranged in the first joint receiving portion and including a heating wire an electrical fusion joint having a mouth heating portion and a second socket heating portion disposed in the second joint socket portion and including a heating wire;
The tube end of the first tube and the tube end of the second tube are butted and fused together inside the electric fusion joint,
plumbing structure.

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