JP2012172688A - Structure and method for connecting composite pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure for connecting a composite pipe capable of easily connecting the composite pipe to another pipe material not only in working piping at a factory but also in site fabrication using an electric fusion joint, and a method for connecting the same.SOLUTION: An insertion sleeve 41 of the electric fusion joint 1a is inserted and fitted to an insertion sleeve fitting part 2a provided at the pipe end of the composite pipe 2 including the inner layer 23 made of a thermoplastic resin and a metal reinforcing layer 22 by diameter expansion treatment to feed a current to an electric resistance heating element 3a buried in a joint body 4a in a coil shape along the outer circumferential surface of the insertion sleeve 41. Thus, the outer circumferential surface of the insertion sleeve 41 and the inner circumferential surface of the inner layer 23 of the insertion sleeve fitting part 2a are fused.

Description

  The present invention is a composite pipe connection structure in which an inner layer used for water supply / hot water supply piping, cold / hot water piping for heating and cooling, or hot water equipment is formed of a thermoplastic resin, and a metal reinforcing layer is formed outside the inner layer. And a connection method.

  Conventionally, the inner and outer layers are made of thermoplastic resin as water / hot-water supply piping, cold / hot water piping for heating and cooling, or piping materials for hot water equipment, and a metal reinforcing layer made of aluminum or the like between the inner and outer layers. (For example, trade name ESLON SUPER ESMOMETAX manufactured by Sekisui Chemical Co., Ltd.) is used. In addition, there are a case where an outer layer is not provided if necessary and a metal reinforcing layer is exposed to the outside, and a case where a cylindrical heat insulating material is further fitted on the outside of the outer layer.

Since the above composite pipe is flexible, it can be bent easily at the site, so it is not necessary to have a joint such as cheese or elbow at the bent part, and simple piping is possible, and the shape can be maintained after bending. It has advantages such as quick positioning and quick connection between the hot and cold water mains and the fan coil unit.
In addition, as a pipe joint for connecting the pipe end of the composite pipe to another piping material, after inserting the composite pipe between the nozzle part (insertion part) fitted with the packing of the joint body and the sleeve, One-touch operation by simply inserting the piping material to be joined by providing a sleeve joint and joint with a sleeve caulking tool and connecting a composite pipe by caulking the sleeve, and having a stopper and water stop mechanism in advance. Pipe joints of a mechanical connection mechanism such as a pipe joint called a one-touch joint that can be connected with a pipe joint and a pipe joint that tightens a cap nut are used.

However, in the case of the pipe joint of the mechanical connection mechanism as described above, there are the following problems.
(1) Since most of the joint body and the like are mainly formed of metal (for example, copper alloy), the cost may increase due to fluctuations in the metal price, and the risk of stable supply is high.
(2) Since most of the joint body and the like are mainly formed of metal (for example, copper alloy), the weight increases and there is a risk of corrosion of the joint body.
(3) Since the number of members constituting the joint is large and they need to be assembled, there is a risk that assembly man-hours and time will be required, defective members may be used during assembly, and product defects such as assembly errors may occur. .
(4) Since the joint is provided with a retaining structure and a water stop structure, there is a problem that the whole joint becomes large and piping work in a narrow place becomes difficult.

  In addition to the mechanical connection structure as described above, there is a fusion method using a butt fusion or an electric fusion joint (Patent Document 1) as a connection method of the thermoplastic resin pipe.

However, there are the following problems in connecting a composite pipe to another piping material using a conventional butt fusion or electric fusion joint.
That is, the butt fusion is such that the end faces of the tubes are melted with a hot plate or the like, and the tube ends are brought into contact with each other. Since it is provided with a metal reinforcing layer that does not melt, it is difficult to apply a surface pressure to the molten resin when the tube end is pressed, and it is difficult to use it for connecting composite tubes.

On the other hand, in the case of the conventional electric fusion joint, after inserting the end portion of the thermoplastic resin pipe material to be connected into the receiving port, the electric resistance heating element provided along the inner peripheral surface of the receiving port is energized. The interface between the inner peripheral surface of the receiving port and the outer surface of the piping material is fused.
However, in the case of the above composite pipe, not only the metal reinforcement layer exposed to the outside, but also the one provided with the outer layer made of thermoplastic resin, the thickness of the outer layer is extremely thin. In the structure of the conventional electric fusion joint, it cannot be fused as it is.

  Therefore, a method has already been proposed in which the outer layer and the intermediate layer of the fusion part are cut off to expose the outer peripheral surface of the inner layer, and then the exposed part of the inner layer is inserted into the receptacle of the electric fusion joint for fusion. (Patent Document 2).

Japanese Patent No. 2639087 JP 2001-31493 A

However, the method of Patent Document 2 has a problem that the outer peripheral surface of the inner layer must be accurately exposed, and on-site construction is very difficult.
Further, in the case of a composite pipe having a metal reinforcing layer, the metal reinforcing layer must be removed by cutting, which makes it difficult to perform on-site construction.
In view of the above circumstances, the present invention uses a composite pipe connection structure that can easily connect a composite pipe to other piping materials in an on-site construction as well as a processing pipe in a factory using an electric fusion joint and It aims to provide a connection method.

  In order to achieve the above object, a composite pipe connection structure according to the present invention comprises a composite pipe comprising an inner layer made of a thermoplastic resin, a metal reinforcing layer surrounding the inner layer, and an insertion opening. The electric resistance heating element comprises an electric fusion joint embedded in the joint body in a coil shape so as to follow the outer peripheral surface of the insertion opening, and the insertion opening is fitted to the insertion opening of the composite pipe end. A composite in which the outer peripheral surface of the insertion port portion and the inner peripheral surface of the inner portion of the insertion port portion are fused by energizing the electric resistance heating element in a state of being inserted and fitted to the portion. In the pipe connection structure, the composite pipe is characterized in that an inner diameter of the insertion port portion fitting portion is formed to have an enlarged diameter substantially the same as an outer diameter of the insertion port portion.

In the present invention, the composite pipe is generally provided with an outer layer made of a thermoplastic resin surrounding the periphery of the metal reinforcing layer, but the outer layer may not be provided.
The thermoplastic resin constituting the inner layer and the outer layer of the composite pipe is not particularly limited, and examples thereof include olefin resins such as polyethylene, polypropylene, and polybutene, and polyvinyl chloride, which are used for applications requiring heat resistance. In the composite tube, it is preferable to use an inner layer having excellent heat resistance such as heat resistant polyethylene resin.

  The electric fusion joint has a cap shape with one insertion port portion, a cheese shape with a plurality of insertion port portions, a nipple shape, a single insertion port portion that is electrically fused to the composite pipe, and other than the composite pipe. The other end connected to the other piping material may have a screw structure, or a receiving shape that can be connected to the other piping material by adhesion or electrofusion.

The material of the joint body of the electric fusion joint is particularly limited as long as the portion contacting the inner peripheral surface when the pipe end of the composite pipe is inserted is formed of a thermoplastic resin that can be fused to the inner layer of the composite pipe. However, it is preferable that the inner layer of the composite pipe is made of the same kind of thermoplastic resin and is entirely made of the same thermoplastic resin.
In other words, if the portion that contacts the inner peripheral surface when the tube end of the composite tube is inserted is formed of at least the same kind of thermoplastic resin as the inner layer of the composite tube, the fusion is good, and the entire joint body is If formed from the same thermoplastic resin, the moldability is excellent.

Moreover, it is preferable that the joint main body is provided with an indicator hole which can visually recognize the electric resistance heating element embedded in the joint main body from a part of the wall surface.
The electric resistance heating element is not particularly limited, and includes a linear heating element body and a thermoplastic resin coating layer surrounding the heating element body, and the thermoplastic resin coating layer includes an inner layer and an inner layer. It is preferable to use those made of the same thermoplastic resin.

  The method for connecting composite pipes according to the present invention includes a pipe end portion of a composite pipe having an inner layer made of a thermoplastic resin and a metal reinforcing layer surrounding the inner layer, the inner diameter of which has an insertion port. The electric resistance heating element is expanded so as to be substantially the same as the outer diameter of the insertion port portion of the electric fusion joint embedded in the joint body in a coil shape so as to follow the outer peripheral surface of the insertion port portion. After forming the mouth fitting portion, the insertion mouth portion is inserted and fitted into the insertion mouth portion fitting portion to energize the electric resistance heating element, and the insertion mouth portion outer peripheral surface and the insertion mouth portion fitting. It is characterized in that the inner layer inner peripheral surface of the joint is fused.

As described above, the connection structure of the composite pipe according to the present invention includes a composite pipe including an inner layer made of a thermoplastic resin and a metal reinforcing layer surrounding the inner layer, an insertion port portion, and an electric resistance. The heating element is composed of an electrofusion joint embedded in the joint body in a coil shape so as to follow the outer peripheral surface of the insertion port portion, and the insertion port portion is inserted into the insertion port portion fitting portion of the composite tube end. Connection of the composite pipe in which the outer peripheral surface of the insertion port and the inner peripheral surface of the inner portion of the insertion port are fused by energizing the electric resistance heating element in a fitted state. It is a structure, Comprising: The said composite pipe is diameter-expanded and formed so that the internal diameter of the said insertion opening part fitting part may be substantially the same as the outer diameter of the said insertion opening part.
Therefore, the composite pipe can be easily connected to other piping materials in the field construction as well as the processing pipe in the factory by using the electric fusion joint.
That is, since the inner peripheral surface of the inner layer of the composite tube and the outer peripheral surface of the insertion port are fused at the insertion port fitting portion of the composite tube, there is no need to cut and remove the outer layer and the metal reinforcing layer of the composite tube. is there.
In addition, since the fusion part is made on the inner surface of the composite pipe, there is less risk of poor fusion due to scratches and dirt on the outer surface of the pipe, and stable connection without causing variations in strength due to the environment or people. Part quality.
Since the joint can be formed by resin injection molding, it is possible to easily produce a large amount of lightweight and inexpensive joints with stable dimensions and no internal defects.
Since the connection between the pipe and the joint can be performed by electric fusion, no special skills are required, and no large equipment is required.
In addition, since the place to connect is not chosen, it can be used not only for prefab production at the factory but also for connection at the construction site.

It is a perspective view showing 1st Embodiment of the connection structure of the composite pipe concerning this invention. It is sectional drawing of the connection structure of FIG. FIG. 3 is an enlarged cross-sectional view of a fused portion in FIG. 2. It is a perspective view of the composite pipe used for the connection structure of FIG. 1, and an electrofusion joint. It is the perspective view which looked at the electric fusion joint of FIG. 4 from the reverse direction. It is a perspective view of the electrical resistance heating element embedded in the electrical fusion joint of FIG. It is sectional drawing showing 2nd Embodiment of the connection structure of the composite pipe concerning this invention. It is sectional drawing showing 3rd Embodiment of the connection structure of the composite pipe concerning this invention. It is a perspective view of the electric fusion joint for bending parts used for the connection structure of the present invention. FIG. 10 is a perspective view of an electric resistance heating element embedded in the electric fusion joint of FIG. 9.

Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof.
1 to 3 show a first embodiment of a composite pipe connection structure according to the present invention.

As shown in FIGS. 1 and 2, in this connection structure A, two composite pipes 2 are connected via an electric fusion joint 1a.
That is, the composite pipe 2 is inserted into the insertion opening part fitting part 2 a provided at the pipe end part by inserting and fitting the insertion part 41 of the electric fusion joint 1 a, and is energized between the terminal terminals 31. The outer peripheral surface of the portion 41 and the outer peripheral surface of the inner layer 23 of the insertion port fitting portion 2a are fused.

More specifically, each composite pipe 2 has a three-layer structure including an inner layer 23 made of heat-resistant polyethylene resin, a metal reinforcing layer 22 made of aluminum, and an outer layer 21 made of high-density polyethylene resin. 2b and an insertion port fitting portion 2a provided at the end of the tube main body 2b.
The insertion port portion fitting portion 2a has a larger diameter than the tube main body portion 2b, and the inner diameter thereof is substantially the same as the outer diameter of the insertion port portion 41 of the electrofusion joint 1a described later.

As shown in FIGS. 4 and 5, the electric fusion joint 1 a has a flange portion 40 in the center, and has a nipple shape in which insertion portions 41 are provided on both sides of the flange portion 40. .
The electric fusion joint 1a includes a joint body 4a formed of the same heat-resistant polyethylene resin as the inner layer 23 of the composite pipe 2, an electric resistance heating element 3a embedded in the joint body 4a, two terminal terminals 31, It has.

As shown in FIG. 3, the electrical resistance heating element 3 a is composed of a linear heating element body 30 a such as a nickel chrome wire or an iron chrome wire, and a polyethylene resin or the like provided so as to surround the heating element body 30 a. It is obtained by bending one coated wire made of a thermoplastic resin coating 30 b, and includes two coil portions 33 and a connecting portion 32 that connects the two coil portions 33.
Then, one end of the terminal terminal 31 is welded and fixed to the heating element body 30a at the end opposite to the connecting portion 32 of each coil portion 33.

The coil portion 33 has an outer diameter that is substantially the same as the outer diameter of the insertion port 41.
The terminal terminal 31 is provided so as to protrude in parallel from the flange portion 40.

As shown in FIG. 5, the flange portion 40 has an indicator hole 42 at a position facing the central portion of the connecting portion 32 so that a part of the connecting portion 32 that is a part of the electric resistance heating element can be visually recognized from the outside. It is installed.
When the composite pipe 2 is normally fusion-bonded, the indicator hole 42 makes it easy to determine whether a part of the resin melted at the time of fusion enters the indicator hole 42 and the fusion is normally performed from the outside. It is provided so that it can be visually recognized.

  Moreover, the electrofusion joint 1a is as described above. The electric resistance heating element 3a obtained by bending the coated wire is set in an injection mold (not shown) while maintaining the bending state, and the thermoplastic resin that becomes the joint body 4a is placed in the injection mold. It is obtained by injection-filling and integrally molding.

This connection structure A is as described above, and the composite pipe 2 can be easily connected to another composite pipe 2 which is another pipe material via the electric fusion joint 1a.
Since the outer peripheral surface of the insertion port 41 is fused to the inner peripheral surface of the inner layer of the composite tube 2, the composite tube 2 is connected to the electrofusion joint 1a without cutting the outer layer 21 and the metal reinforcing layer 22. It is possible to connect to other composite pipes 2 which are other piping materials via.

Moreover, since it can fuse | fuse only by supplying with electricity between the terminal terminals 31, there is little danger and it can be set as the stable connection part quality, without producing the environment and the variation of construction by a person.
Furthermore, since the place to connect is not chosen, it can be used not only for prefab production at the factory but also for connection at the construction site.

Since the electric fusion joint 1a that can be formed by injection molding is used as the joint, the joint dimensions are stable, there is no internal defect, and the light weight can be produced in large quantities at low cost. Therefore, the construction cost can be reduced.
Moreover, since the insertion port part fitting part 2a is diameter-expanded from the pipe | tube main-body part 2b, when the internal diameter of the insertion port part 41 can be enlarged, the dew area in the electrofusion joint 1a part which flows through the inside of piping It is possible to reduce the pressure loss due to the reduction in size.

Next, the connection method of the present invention will be described by taking as an example the case of using the product name ESLON SUPER ESMOMETAX manufactured by Sekisui Chemical Co., Ltd. having a diameter of 13 mm as the composite pipe 1a used in the connection structure A.
(1) An electric fusion joint 1a (the wire diameter of the heating element body 30a is 1.2 mm) having an insertion opening 41 having an outer diameter of 15.6 mm and an inner diameter of 7.9 mm (wall thickness: 3.85 mm) is injection-molded. .
(2) The pipe end part of the above-mentioned Eslon Super Esromettax is expanded to form a composite pipe 2 having an insertion port fitting part 2a having an inner diameter of 15.6 mm.
(3) The insertion port portions 41 are respectively fitted to the insertion port portion fitting portions 2 a of the composite tube 2 until the tube end surface of the composite tube 2 contacts the flange portion 40.
(4) The composite pipe 2 and the electric fusion joint 1a are fixed so as not to be pulled out by a clamp (not shown) (the clamp is not essential in an environment where the risk of movement is small).
(5) The terminal of the fusion controller (not shown) is connected to the terminal terminal 31 and energized for 20 seconds.
(6) After the connecting portion has cooled sufficiently, the clamp is opened and it is confirmed that the molten resin has flowed out of the indicator hole 42.

FIG. 7 shows a second embodiment of the composite pipe connection structure according to the present invention.
As shown in FIG. 7, this connection structure B is arranged so that the joint body 4b of the electrofusion joint 1b surrounds the insertion port fitting portion 2a of the composite pipe 2 from the outside in parallel to the insertion port portion 44. It is the same as that of the said 1st Embodiment except having the outer cylinder part 45 which has the internal diameter substantially the same as the outer diameter of the insertion port part fitting part 2a, or a little larger.

Since the connection structure B includes the outer cylinder portion 45 as described above, the molten resin wraps around from the distal end surface of the insertion port fitting portion 2a to the outer peripheral surface of the insertion port fitting portion 2a, and is combined. The tube 2 and the electric fusion joint 1b can be fused more firmly, and the portion of the metal reinforcing layer 22 exposed at the distal end surface of the insertion port fitting portion 2a can be more reliably sealed.
In addition, the outer cylinder portion 45 can prevent the outer surface of the insertion port fitting portion 2a from being damaged and adhere to dust, which can cause poor fusion in the state of the joint before connection, and can be directly touched by hand. Can prevent the attachment of sebum and the like.

FIG. 8 shows a third embodiment of the composite pipe connection structure according to the present invention.
As shown in FIG. 8, this connection structure C is similar to the first embodiment except that the electrofusion joint 1c includes an in-core 5 for reinforcement inside the joint body 4c. It has become.
The in-core 5 is made of stainless steel, copper alloy (for example, gunmetal, brass), engineering plastic (for example, PPS, PPSU), etc., and generates electrical resistance in advance when the electric fusion joint 1c is injection molded. It is set in the injection mold together with the body 3a.

Since the in-core 5 is provided in the connection structure C as described above, the thickness of the insertion opening 41 of the joint body 4c can be reduced. Even if the thickness of the insertion opening 41 of the joint body 4c is reduced, the insertion opening 41 is not deformed in the inner diameter direction by heat melting.
That is, the inner diameter of the insertion opening 41 can be increased without increasing the outer diameter of the electric fusion joint 1c, and the fusion workability in a narrow area can be improved.

FIG. 9 shows another example of the electric fusion joint used for the connection structure of the composite pipe according to the present invention.
As shown in FIG. 9, this electric fusion joint 1d is provided so that two insertion openings 47 are orthogonal to each other, and is used for a bent pipe portion.

As shown in FIG. 10, the electric resistance heating element 3b is the same as the electric resistance heating element 3a except that the two coil portions 33 are arranged so that the central axes of the coils are orthogonal to each other. Yes.
In FIG. 9, reference numeral 46 denotes a flange portion.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the two insertion openings have the same diameter. However, the insertion openings may have different diameters so that composite pipes having different diameters can be connected to each other.
In the above embodiment, the two coil portions are conducted through the connecting portion, and the two composite pipes can be fused simultaneously by energizing the two terminal terminals. In addition, two terminal terminals may be fused for each insertion port, one composite tube.

In the above embodiment, there is one indicator hole, but a plurality of indicator holes may be provided.
In the above embodiment, the coated wire material in which the heating element body is coated with the thermoplastic resin is used as the electric resistance heating element. However, in the mold, the heating element body adjacent to the coil portion is not short-circuited at the time of injection molding. As long as it can arrange | position to this, you may make it use the thing with a heat generating body main body exposed.

A, B, C Connection structure 1a, 1b, 1c Electrical fusion joint 2 Composite tube 2a Insertion port fitting portion 2b Tube body 21 Outer layer 22 Metal reinforcement layer 23 Inner layers 3a, 3b Electric resistance heating element 30a Heating element body 30b Heat Plastic resin coating 31 Terminal terminal 32 Connecting part 33 Coil parts 4a, 4b, 4c Joint body 41, 44, 47 Insertion part 42 Indicator hole

Claims (3)

A composite pipe comprising an inner layer made of a thermoplastic resin and a metal reinforcing layer surrounding the inner layer;
It has an insertion opening part, and consists of an electric fusion joint embedded in the joint body in a coil shape so that the electric resistance heating element follows the outer peripheral surface of the insertion opening part,
In the state where the insertion port portion is inserted and fitted into the insertion port portion fitting portion of the composite pipe tube end, the electrical resistance heating element is energized, whereby the outer peripheral surface of the insertion port portion and the insertion port portion It is a connection structure of a composite pipe in which the inner layer inner peripheral surface of the fitting portion is fused,
The composite pipe connection structure according to claim 1, wherein an inner diameter of the insertion port portion fitting portion is formed so as to be increased in diameter substantially the same as an outer diameter of the insertion port portion.   The composite pipe connection structure according to claim 1, wherein the composite pipe includes an outer layer made of a thermoplastic resin surrounding the periphery of the metal reinforcing layer. A pipe end portion of a composite pipe comprising an inner layer made of a thermoplastic resin and a metal reinforcing layer surrounding the inner layer has an inner diameter of
It has an insertion opening, so that the electrical resistance heating element is substantially the same as the outer diameter of the insertion opening of the electric fusion joint embedded in the joint body in a coil shape so as to follow the outer peripheral surface of the insertion opening. After expanding the diameter and forming the insertion port fitting part,
The insertion port portion is inserted and fitted into this insertion port portion fitting portion, and the electric resistance heating element is energized to melt the insertion port portion outer peripheral surface and the inner layer inner peripheral surface of the insertion port portion fitting portion. A method of connecting composite pipes characterized by wearing.

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