JP2001116182A - Resin pipe joint with electrothermal fusion joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin joint for a resin pipe comprising two layers having an electrothermal fusion joint preventing the leaking of water due to aging, inhibiting sagging deformation, and having little resistance to flow. SOLUTION: A hollow joint body has a base part with a tubular body and a ring-shaped portion, and also has a stopper in a portion inwardly away from the ring-shaped portion. The tubular body made from an uncrosslinked or crosslinked thermoplastic resin has an annular recess between a position inward of an open end and the side face of the ring-shaped portion, and the side face of the ring-shaped portion on at least the pipe insertion side of the base part is made from an uncrosslinked thermoplastic resin different from that of the tubular body. The electrothermal fusion joint is a bobbin-like hollow body formed of a helically wound coil of a continuous heating wire covered with an uncrosslinked thermoplastic resin. The bobbin-like hollow body is positioned within the recess in the tubular body and a turn of the resin-covered wire at the end of the hollow body is brought into contact with the side face of the base part of the ring-shaped portion throughout its periphery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin pipe joint having an electrothermal fusion joint, and more particularly, to a resin pipe joint used as a conduit for water or hot water and having a non-crosslinked thermoplastic resin on its surface layer. Resin joints that are connected via an electrothermal fusion joint, especially, while maintaining sufficient joint strength and excellent water leakage resistance at the joint, a resin pipe with greatly reduced flowing water resistance in the joint For joints.

[0002]

2. Description of the Related Art Crosslinked polyolefin pipes, such as crosslinked polyethylene, having a melting point higher than the ignition point under normal atmospheric pressure, excellent heat resistance, and sufficient strength are used for resin pipes as conduits for water or hot water. Is used. This kind of resin pipe cannot obtain a sufficient adhesive strength even if it is a joint made of the same kind of resin as well as a joint made of another material.

Further, since a working pressure of a water or hot water pipe is high, and particularly a hot water pipe is always in a high temperature state, two or more resin pipes are connected to each other by mechanical means such as sealing by compression. We have to rely on joints with means, for example metal joints.

[0004] However, such a joint having mechanical means causes a complicated structure and consequently a reduction in workability in connecting the resin pipe, and in addition, the use of the resin pipe and the sealing material with the passage of time. There is a problem in that the sealing property is reduced due to stress relaxation, and eventually water leakage is caused.

[0005] Therefore, an electrofusion joint that has solved the above-mentioned problems has come to be used. In other words, this type of joint having an electrothermal fusion joint uses a two-layer resin pipe in which a thin gauge non-crosslinked polyethylene layer is applied to the surface and a crosslinked polyethylene layer thicker than the surface is applied to the inner body layer. Therefore, it has a configuration that can prevent water leakage for a long period of time and can obtain sufficient bonding strength with the resin pipe.

However, even in the above-mentioned electrofusion joint, when connecting a thin resin pipe, there is a problem that the resin pipe portion of the joining portion is sagged inward due to heat.ー 2704
No. 990 proposes a joint 36 having an electrofusion portion 35 provided with a support layer 34 for supporting an inner surface of a resin pipe 33 inserted into an insertion groove 32 of a joint main body 31 as shown in a sectional view of FIG. are doing.

[0007]

However, in the joint 36 disclosed in the above publication, how thin the resin pipe 3 is
However, the support layer 34 must have the appropriate gauge to prevent inward deformation. This causes a problem in that the support layer 34 impedes the flow of water or hot water at the joint 36 and significantly increases the flow path resistance. In particular, in the case of the joint 36 of the resin pipe 33 having a small diameter, the accident of closing the joint 36 during the use of the hot water may occur, or the joint 36 may be deformed inward at the temperature of the hot water. There is a problem of a remarkable increase in flow path resistance, such as an extreme decrease in

Accordingly, the invention described in claims 1 to 13 of the present invention is characterized in that a non-crosslinked polyolefin layer such as a thin gauge non-crosslinked polyethylene layer is applied to the surface layer, and a crosslinked polyolefin layer such as a thicker gauge crosslinked polyethylene layer is applied. Assuming a joint that connects two or more resin pipes of polyolefin such as polyethylene with a two-layer structure applied to the inner layer body, it has sufficient joint strength and excellent durability in long-term use, water leakage, etc. It is an object of the present invention to provide a resin pipe joint having an electrothermal fusion joint that can minimize flow path resistance without causing the above problem.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a hollow joint body made of a thermoplastic resin, and a hollow joint body which is spaced apart from the inside of the joint body. In a resin pipe joint comprising at least one or more electrothermal fusion joints and a space inside each of the electrothermal fusion joints for inserting a resin pipe whose surface layer is made of a non-crosslinked thermoplastic resin, the joint main body is provided at two positions. A tubular body into which a pipe is inserted from the above opening, a base joined to the inner surface inside the tubular body opening, and having one or more ring-shaped portions on each pipe insertion side, and a ring-shaped portion of the base A stopper protruding from the remote portion toward the hollow space and locking each of the plurality of pipes to be inserted; the tubular body has an inner position at each open end into which the plurality of pipes are inserted; Ring-shaped part facing the position Has a plurality of annular recesses extending between the parts side, the tubular body is made of non-crosslinked thermoplastic resin and one of the resin of crosslinked thermoplastic resin, the base,
At least the ring-shaped portion side surface on the pipe insertion side is made of a non-crosslinked thermoplastic resin different from the tubular body, and each of the two or more electrothermally melted joints is formed of one or more continuous heating wires by the non-crosslinked thermoplastic resin. The bobbin-shaped hollow body of the spirally wound coil of the coated resin-coated wire is formed, and each bobbin-shaped hollow body is arranged in each concave portion of the tubular body, and one end of each bobbin-shaped hollow body is covered with the resin-coated wire. A resin pipe joint having an electrothermal fusion joint characterized by being brought into contact with a ring-shaped portion base side surface over the entire circumference.

According to the first aspect of the present invention, there is provided a second aspect.
As in the invention described in the above, the base has a joint surface with the tubular body on at least the outer peripheral surface of the outer peripheral surface and the ring-shaped partial side surface, and the ring-shaped partial base has a contact side surface with the bobbin-shaped hollow body. Has a concavo-convex surface covering the entire side surface of the one-turn resin-coated wire at the end of the bobbin-shaped hollow body.

According to the first and second aspects of the present invention, as in the third aspect, the ring-shaped portion base has an outer peripheral surface having a diameter equal to or larger than the outer diameter of the adjacent concave portion.

According to the invention described in claims 1 to 3, as in the invention described in claim 4, the stopper has a shape continuously projecting in the circumferential direction from the base of the ring-shaped portion.

[0013] In addition to the invention described in claim 4, with respect to the inventions described in claims 1 to 3, as in the invention described in claim 5, the stopper is interrupted in the circumferential direction from the ring-shaped portion base. It has a protruding shape.

According to the first to fifth aspects of the present invention, as in the sixth aspect of the present invention, the stopper has an inner diameter greater than the minimum inner diameter of the pipe to be inserted.

According to the invention described in the first to sixth aspects, as in the invention described in the seventh aspect, each bobbin-shaped hollow body is made of a tightly wound spiral wound coil of a resin-coated wire having a round cross-sectional shape. And a replenishing resin member in which the same type of resin is replenished at least in the concave portion on the surface side between adjacent resin-coated wires of the coil.

[0016] In addition to the invention described in claim 7, in the invention described in claims 1 to 6, each of the bobbin-shaped hollow bodies has a resin coating having a square cross section as in the invention described in claim 8. It has a wire tight spiral wound coil.

According to the first to eighth aspects of the present invention, as in the ninth aspect of the present invention, the plurality of bobbin-shaped hollow bodies have a minimum inner diameter smaller than the inner diameter of each resin pipe insertion opening of the tubular body. Have.

According to the first to ninth aspects of the present invention, as in the tenth aspect, the tubular body is made of a polypropylene resin as the non-crosslinked thermoplastic resin. Also,
Separately from this, as in the invention described in claim 11, the tubular body is made of one of a crosslinked polyethylene and a radiation crosslinked polypropylene as the crosslinked thermoplastic resin.

According to the invention described in the first to eleventh aspects, as in the invention described in the twelfth aspect, at least the ring-shaped part side portion of the base portion on the pipe insertion side, the stopper, and the heating wire coating resin are each formed of a non-crosslinking heat. The plastic resin is made of one of non-cross-linked polyethylene and poly-1-butene having an isotactic structure.

Regarding the entire invention described in claims 1 to 12, as in the invention described in claim 13, the tubular body of the joint body is formed of a straight pipe and a bent pipe of a single form and a T-shaped pipe of a composite form. It has one form to choose from.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 3 are sectional views of a plane including a center line of the resin pipe joint according to the present invention, and FIGS. 4 and 5 are partially enlarged cross sections of the left half of the resin pipe joint shown in FIG.

1 to 3, a resin pipe joint 1 is shown.
Is a hollow joint body 2 and two or more electrothermal fusion joints 3
-1, 3-2, 3-3 (shown only in FIG. 3) and two or more resin pipes (indicated by a two-dot chain line) inside each of the electrothermal fusion joints 3-1, 3-2, 3-3. ) Hollow space 5 for inserting 4
1, 5-2 and 5-3 (only shown in FIG. 3). These internal spaces 5-1, 5-2, and 5-3 communicate with each other via a space 6 in the center of the joint body 2. As the resin pipe 4, a small-diameter pipe having a diameter of 50 mm or less is suitable.

Electrothermal fusion joints 3-1, 3-2, 3-3
Are spaced apart inside the joint body 2. The joint body 2 is made of a thermoplastic resin. The resin pipe 4 has a two-layer structure, the surface layer 4a is made of a non-crosslinked thermoplastic resin, and the inner layer 4b
Consists of a crosslinked thermoplastic resin. The gauge of the surface layer 4a is 0.
The range is 2 to 0.6 mm, and the gauge of the inner layer 4b is within the range of 1.2 to 7.5 mm.

The joint body 2 has a tubular body 10, a base 11, and a stopper 12. The tubular body 10 has two or more openings corresponding to the number of the resin pipes 4 connected to each other, and the resin pipes 4 are inserted from the respective openings. The tubular body 10 shown in FIGS. 1 and 2 has two openings, and the tubular body 10 shown in FIG. 3 has three openings. The tubular body 10 shown in FIG. 1 is a single-shaped body that extends straight, and the tubular body 10 shown in FIG. 2 is a single-shaped body that is curved at the center and extends straight at both ends. The tubular body 10 shown in FIG. 3 is a T-shaped composite body extending straight.

The base 11 is joined to the inner surface inside the opening of the tubular body 10, and a ring-shaped portion 13
Is provided. The base 11 shown in FIG. 1 has one ring-shaped portion 13 over the entire width. The base 11 shown in FIG. 2 includes two ring-shaped portions 13 (one surface is indicated by a two-dot chain line) at both end portions. The base 11 shown in FIG. 3 includes two opposing ring-shaped portions 13 (one surface is indicated by a two-dot chain line) and 1
And two ring-shaped portions 13 (one surface is indicated by a two-dot chain line).

The stopper 12 protrudes from the remote portion inside the ring-shaped portion 13 of the base 11 toward the hollow space of the tubular body 10 and locks each of the plurality of resin pipes 4 to be inserted. The first important point is that the stopper 12 protrudes from the inner remote portion of the ring-shaped portion 13. That is, the projecting position of the stopper 12 is to be as far away as possible as far as possible inward from the outer end of the ring-shaped portion 13.

The tubular body 10 has a plurality of portions extending between an inner position of each open end into which two or more resin pipes 4 are inserted and a side surface of the ring-shaped portion 13 of the base 11 facing the inner position. It has an annular recess 14. The tubular body 10 shown in FIGS. 1 and 2 has two annular recesses 14, and the tubular body 10 shown in FIG. 3 has three annular recesses 14.

Hereinafter, referring to FIGS. 4 and 5, each of the two or more electrothermal fusion joints 3-1, 3-2, and 3-3 connects one or more continuous heating wires 15 with non-crosslinking heat. It is formed by a bobbin-shaped hollow body 18 having a spirally wound coil of a resin-coated wire 17 covered with a plastic resin 16. In addition, the electrothermal fusion joints 3-1, 3-2, and 3-3 have a lead wire that connects the resin-coated wire 17 at the end of the bobbin-shaped hollow body 18 to the terminal 20 embedded in the tubular body 10. The heating wire 15 is suitable for a general nickel chrome wire for heating.

Since the bobbin-shaped hollow body 18 does not have a bobbin shape if there is a gap between the adjacent resin-coated wires 17, as shown in FIGS. It is advantageous and may be advantageously formed. Heating wire 15
A resin that completely melts at a relatively low temperature is applied to the coated non-crosslinked thermoplastic resin.

The above-mentioned tubular body 10 can be formed by both a non-crosslinked thermoplastic resin and a crosslinked thermoplastic resin. On the other hand, the base 11
Is a ring-shaped portion 13 at least on the resin pipe 4 insertion side.
The side portion is formed of a non-crosslinked thermoplastic resin different from the tubular body 10. This is because it is necessary to apply a resin having the same properties as the resin pipe 4 having excellent heat resistance and sufficient strength to the tubular body 10, whereas the base 11 is
This is because at least the side surface of the ring-shaped portion 13 on the resin pipe 4 insertion side needs to have a characteristic of completely melting at a relatively low temperature, which will be described later. In each of the drawings, an example is shown in which the entire base 11 including the stopper 13 is formed of a non-crosslinked thermoplastic resin different from the tubular body 10.

Each bobbin-shaped hollow body 18 is arranged in each annular concave portion 14 of the tubular body 10. The second important point is that the one-turn resin-coated wire 17L at the end of each bobbin-shaped hollow body 18 is brought into contact with the side surface of the ring-shaped portion 13 of the base 11 over the entire circumference. The side surface of the ring-shaped portion 13 with which the one-turn resin-coated wire 17L contacts is the surface of the side surface of the ring-shaped portion 13 on the resin pipe 4 insertion side.

The resin pipe joint 1 having the configuration described above
Connects the resin pipes 4 to each other by the operation described below. That is, each resin pipe 4 is inserted into the tubular body 10 and locked to the stopper 13. In a state where the locking is held, electric power is supplied to the heating wire 15 of the bobbin-shaped hollow body 18 via the terminal 20. The heating wire 15 generated by energization melts the non-crosslinked thermoplastic resin of the bobbin-shaped hollow body 18, and simultaneously, the non-crosslinked thermoplastic resin of the surface layer 4 a of each resin pipe 4,
Ring-shaped portion 1 in contact with one turn of resin-coated wire 17L
3. Melt the non-crosslinked thermoplastic resin at the periphery of the three side surfaces.

The electrothermal fusion joints 3-1, 3-2, 3-
3, the coating resin 16 of the heating wire 15 and 1
The resin of the ring-shaped portion 13 on the side in contact with the wound resin-coated wire 17L and the resin of the surface layer 4a of the resin pipe 4 are integrated. By this integration, the resin pipes 4 are firmly connected to each other via the resin pipe joint 1.

When the coating resin 16 of the heating wire 15, the resin of the surface layer 4a, and the resin of the ring-shaped portion 13 are completely melted, these resins expand thermally and their volumes increase. The resin whose volume has increased breaks a thin diaphragm between each concave portion 14 and the indicator hole 21 due to the expansion pressure, and fills the inside of the indicator hole 21 and rises. Thereby, sufficient fusion bonding of each part can be visually confirmed.

Here, even if the resin 16 of the bobbin-shaped hollow body 18 and the resin of the tubular body 10 have not been melted and joined, the ring-shaped portion 13 on the side in contact with the single-turn resin-coated wire 17L is formed. Since the resin and the resin 16 filling the recess 14 are completely melt-bonded to each other, the high-pressure water or high-pressure hot water inside the resin pipe 4 does not leak to the outside. This is the key to preventing water leakage.

The dripping deformation of the resin pipe 4 into the hollow space due to the high temperature occurs at the tip of the cut end of the resin pipe 4. However, this resin pipe joint 1 has a stopper 12 protruding from a remote portion inward of the ring-shaped portion 13, and one end of the resin pipe 4 locked to the stopper 13 and one end of the end of the bobbin-shaped hollow body 18. Since the separation distance from the covering wire 17L is made as long as possible, as shown in FIG. 6, the tip of the resin pipe 4 is sagged without providing a support such as a support layer 34 for supporting the inner surface of the resin pipe 33. Can be prevented.

In general, a large number of resin pipe joints used for water supply and hot water supply for a building or the like are provided along a certain flow path, and especially when the resin pipe 4 has a small diameter of 50 mm or less, the resin pipe 4 The flow path resistance of the support for preventing the sagging deformation located inside the inside cannot be ignored. However, when the resin pipe joint 1 of the present invention is used, there is no extra matter that forms a flow path resistance inside the joint 1, and therefore, the desired flow rate (m ³ / min)
, Cm ³ / sec), and there is no need to increase the original water pressure or hot water pressure excessively, which enables smooth water supply and hot water supply.

Hereinafter, details of the resin pipe joint 1 will be described. First, the base 11 has a joint surface with the tubular body 10 on at least the outer peripheral surface of the outer peripheral surface and the side surface of the ring-shaped portion 13. That is, the base 11 shown in FIGS. 1 to 4 has a joint surface with the tubular body 10 only on its outer peripheral surface, and the base 11 shown in FIG. It has a joint surface with the tubular body 10. 5 is suitable for a case where the resin of the tubular body 10 and the resin of the base 11 are different and the joining force is low.

Further, the ring-shaped portion 13 of the base 11 has an uneven surface on the side in contact with the bobbin-shaped hollow body 18 so as to cover all the side faces of the one-turn resin-coated wire 17L at the end of the bobbin-shaped hollow body 18. By doing so, the side surface of the ring-shaped portion 13 and the resin-coated wire 17 including the lead-out of the ring-shaped portion 13 are drawn.
Full contact with L can be guaranteed.

Next, the ring-shaped portion 13 of the base 11 is
It has an outer peripheral surface having a diameter equal to or larger than the outer diameter of the adjacent concave portion 14. This case is the ring-shaped part 13 shown in FIGS. 2, 3 and 5.

Next, the stopper 12 has a shape continuously projecting in the circumferential direction from the ring-shaped portion 13 of the base 11. A typical example of this is the stopper 12 shown in FIG. However, the stopper 12 shown in FIGS. 2 and 3 may have a shape continuously projecting in the circumferential direction.

Next, the stopper 12 has a shape that protrudes from the ring-shaped portion 13 of the base 11 in the circumferential direction. A typical example of this is the stopper 12 shown in FIGS. 2 and 3, the way in which the stopper 12 is interrupted in the circumferential direction is indicated by a two-dot chain line. However, the stopper 12 shown in FIG. Stopper 12
One of the roles is to position the insertion of the resin pipe 4, so that it is not always necessary to continue in the circumferential direction. By doing so, the amount of resin used is reduced, which contributes to cost reduction. In this sense, the stopper 12 shown in FIGS. 2 and 3 is preferably cut out in the longitudinal direction of the tubular body 10. This notch is also indicated by a two-dot chain line.

Next, referring to FIGS. 1 to 4, each bobbin-shaped hollow body 18 has a tightly wound spiral wound coil of a resin-coated wire 17 having a round cross-sectional shape. In this case, at least the concave portion on the surface side between the resin-coated wires 17 adjacent to the coil,
The same resin as the coating resin 16 of the heating wire 15 is supplemented to make the surface of each bobbin-shaped hollow body 18 substantially smooth. By doing so, it is possible to prevent a part of the resin of the tubular body 10 from flowing into the inner surface of each bobbin-shaped hollow body 18 during the injection molding of the resin pipe joint 1 described later. The same resin may be replenished in the inner concave portion for safety.

In order to save the trouble of resin replenishment, FIG.
As shown in (1), each bobbin-shaped hollow body 18 is formed by a tightly wound spiral wound coil of a resin-coated wire having a rectangular cross-sectional shape. In this case, there is an advantage that the manufacturing cost can be reduced because the number of steps for replenishing the resin is small.

The plurality of bobbin-shaped hollow bodies 18 are
0 has a minimum inner diameter equal to or smaller than the inner diameter of the insertion opening of each resin pipe 4. Generally, the opening of the tubular body 10 has a clearance of about 0.1 to 0.4 mm with respect to the outer diameter of the resin pipe 4. In the case of a large clearance, when the minimum inner diameter of the bobbin-shaped hollow body 18 is adjusted to the inner diameter of the opening of the tubular body 10,
Resin pipe 4 and electrothermal fusion joints 3-1, 3-2, 3-3
Therefore, the minimum inner diameter of the bobbin-shaped hollow body 18 must be equal to or less than the inner diameter of the opening of the tubular body 10 because the mutual fusion bonding with the hollow body becomes insufficient. Note that the minimum inner diameter is when the resin-coated wire 17 having a round cross-sectional shape is applied to each bobbin-shaped hollow body 18.

Next, the types of resin will be described. For the resin of the tubular body 10, practically, preferably, a case where polypropylene is applied as a non-crosslinked thermoplastic resin and a case where either one of a crosslinked polyethylene and a radiation crosslinked polypropylene is applied as a crosslinked thermoplastic resin. Both fit.

At least the side surface of the ring-shaped portion 13 of the base 11 on the resin pipe 4 insertion side, the stopper 12 and the heating wire 1
For each of the coating resins 16 of No. 5, it is practically suitable to apply any one of non-crosslinked polyethylene and poly-1-butene having an isotactic structure as a non-crosslinked thermoplastic resin. The base 11 shown in each drawing is entirely made of one of the above resins. When a part of the base 11 is made of one of the resins as described above, the same resin as the tubular body 10 can be applied to the remaining base 11. In any case, the stopper 12
It is convenient on production for the base 11 and the stopper 12 to be made of the same resin.

Next, the tubular body 10 of the joint body 2 is shown in FIG.
A straight pipe having a single form as shown in FIG. 2, a bent pipe having a single form as shown in FIG. 2, and a T-shaped pipe having a composite form as shown in FIG. 3 are suitable. Although not shown, a U-shaped tube may be applied to the tubular body 10 as a bent tube. The resin pipe joint 1 having the joint body 2 has the names of a socket joint for a straight pipe, an elbow joint for a bent pipe, and a cheese joint for a T-shaped pipe.

Finally, a method of manufacturing the resin pipe joint 1 will be briefly described. First, a resin-coated wire 17 is attached to a cylindrical mandrel.
Are wound while being spirally contacted with each other to form a bobbin-shaped hollow body 18. At this time, in the case where the bobbin-shaped hollow body 18 does not have the terminals 20 on both sides in FIGS. 1 to 3, two bobbin-shaped hollow bodies 18 are formed by a continuous resin-coated wire 17. If the resin-coated wire 17 has a round cross section, the same resin is added to at least the concave portion on the surface side of the adjacent resin-coated wire 17 to finish the hollow body 18 into a bobbin shape. The lead wire of the bobbin-shaped hollow body 18 is connected to a terminal 20.

Next, when the mandrel for spirally winding the resin-coated wire 17 also serves as a mandrel for injection molding, a mandrel having a concave portion necessary for molding the stopper 12 and a base 11 outside the mandrel are provided. The base 11 including the ring-shaped portion 13 and the stopper 12 are molded by injection molding using an outer mold to be molded. At this time, the side surface of the ring-shaped portion 13 forms an uneven surface that covers the entire side surface of the one-turn resin-coated wire 17L at the end of the bobbin-shaped hollow body 18.

Subsequently, with the bobbin-shaped hollow body 18 and the base 11 including the stopper 12 and the ring-shaped portion 13 positioned on the mandrel, these are covered with an outer mold, and the applied resin is injected into an injection molding machine. The tubular body 10 is supplied and molded by injection molding. At this time, an indicator hole 21 is also formed.
When the resin of the tubular body 10 is cross-linked polyethylene, a resin material in which a cross-linking agent such as silane is blended in advance with polyethylene is supplied to an injection molding machine. With this, the molding of the resin pipe joint 1 is completed. Thereafter, the outer mold is opened, the mandrel is pulled out to the opening side of the tubular body 10, and the molded resin pipe joint 1 is taken out.

When the resin of the tubular body 10 is a crosslinked polyethylene, a heat treatment for causing the removed tubular body 10 to undergo a crosslinking reaction is required. The heat treatment conditions vary depending on the type of the cross-linking agent.
Exposure for about 10 hours in an atmosphere of ° C. Thus, the resin pipe joint 1 is completed. The heating source is hot water or steam. Base 1
When 1 or a portion thereof and the heating wire coating resin 16 are non-crosslinked polyethylene, the polyethylene of the tubular body 10 and the base portion 11 or a portion thereof and the heating wire coating resin 16 are strongly bonded to each other during the crosslinking reaction. It has the advantage of combining.

On the other hand, when the resin of the tubular body 10 is polypropylene, the resin pipe joint 1 is completed in a state where the resin is taken out from the outer mold and the mandrel is pulled out. Therefore,
In this case, the post-processing as described above can be omitted, and there are advantages of high productivity and low cost. When the resin of the tubular body 10 is radiation-crosslinked polypropylene, the extracted tubular body 10 is irradiated with radiation to complete the resin pipe joint 1.
In this case as well, there is an advantage of high productivity because radiation irradiation for a short time is sufficient.

[0054]

According to the first to thirteenth aspects of the present invention, the flow path can be formed without causing problems such as water leakage under sufficient bonding strength and excellent durability in long-term use. After suppressing the resistance to the minimum, it is possible to interconnect a two-layer resin pipe using a thin gauge non-crosslinked polyolefin layer on the surface layer and a thicker gauge crosslinked polyolefin layer for the inner layer body. A resin pipe joint having an electrothermal fusion joint can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a socket type resin pipe joint according to the present invention.

FIG. 2 is a sectional view of an elbow type resin pipe joint according to the present invention.

FIG. 3 is a sectional view of a teeth type resin pipe joint according to the present invention.

FIG. 4 is a partially enlarged cross section of the left half of the resin pipe joint shown in FIG.

FIG. 5 is a partially enlarged sectional view of a left half of a resin pipe joint having a resin-coated wire different from that of FIG. 4;

FIG. 6 is a sectional view of a conventional resin pipe joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin pipe joint 2 Joint main body 3 Electrothermal fusion joining part 4 Resin pipe 4a Resin pipe surface layer 4b Resin pipe inner layer 5 Hollow space 6 Joint main body central part space 10 Tubular body 11 Base 12 Stopper 13 Ring part 14 Annular concave part 15 Heating wire 16 Heating wire-coated resin 17 Resin-coated wire 17L One-turn resin-coated wire at end 18 Bobbin-shaped hollow body 20 Terminal 21 Indicator hole

Claims (13)

[Claims] 1. A hollow joint body made of a thermoplastic resin, two or more electrothermal fusion joints spaced apart inward of the joint body, and a non-crosslinked surface layer inside each of the electrothermal fusion joints. A resin pipe joint comprising a space for inserting a resin pipe made of a thermoplastic resin, wherein the joint body is joined to a tubular body into which a pipe is inserted from two or more openings and an inner surface inside the tubular body opening. A base having one or more ring-shaped portions on each pipe insertion side, and a stopper projecting from the inner remote portion of the ring-shaped portion of the base toward the hollow space and locking each of the plurality of pipes to be inserted; The tubular body has a plurality of annular recesses extending between an inner position of each open end into which the plurality of pipes are inserted, and a ring-shaped portion base side surface facing the inner position, Body is non-crosslinked thermoplastic resin And the base portion is made of a non-crosslinked thermoplastic resin having a ring-shaped portion side surface at least on the pipe insertion side different from the tubular body, and the two or more electrothermal fusion joints Each consists of a bobbin-shaped hollow body of a spirally wound coil of a resin-coated wire in which one or more continuous heating wires are coated with a non-crosslinked thermoplastic resin, and each bobbin-shaped hollow body is arranged in each concave portion of a tubular body. A resin pipe joint having an electrothermal fusion joint, wherein one end of a resin-coated wire at the end of each bobbin-shaped hollow body is brought into contact with the side surface of the ring-shaped portion base over the entire circumference. 2. The base has a joint surface with the tubular body on at least the outer peripheral surface of the outer peripheral surface and the ring-shaped portion side surface, and
2. The resin pipe joint according to claim 1, wherein the ring-shaped portion base has an uneven surface on the side surface in contact with the bobbin-shaped hollow body, which covers the entire side surface of the one-turn resin-coated wire at the end of the bobbin-shaped hollow body. 3. The resin pipe joint according to claim 1, wherein the ring-shaped portion base has an outer peripheral surface having a diameter equal to or larger than an outer diameter of an adjacent concave portion. 4. The resin pipe joint according to claim 1, wherein the stopper has a shape continuously projecting in a circumferential direction from the base of the ring-shaped portion. 5. The resin pipe joint according to claim 1, wherein the stopper has a shape intermittently projecting from the base of the ring-shaped portion in the circumferential direction. 6. The resin pipe joint according to claim 1, wherein the stopper has an inner diameter greater than or equal to a minimum inner diameter of the pipe to be inserted. 7. Each bobbin-shaped hollow body is filled with the same kind of resin in at least a surface-side concave portion between a resin-coated wire having a round cross-section and a resin-coated wire and between adjacent resin-coated wires of the coil. The resin pipe joint according to any one of claims 1 to 6, further comprising a supplementary resin member. 8. The resin pipe joint according to claim 1, wherein each bobbin-shaped hollow body has a tightly wound spirally wound coil of a resin-coated wire having a square cross section. 9. The resin pipe joint according to claim 1, wherein the plurality of bobbin-shaped hollow bodies have a minimum inner diameter that is equal to or less than the inner diameter of each resin pipe insertion opening of the tubular body. 10. The resin pipe joint according to claim 1, wherein the tubular body is made of a polypropylene resin as the non-crosslinked thermoplastic resin. 11. The tubular body as a crosslinked thermoplastic resin,
The resin pipe joint according to any one of claims 1 to 9, comprising a resin of one of crosslinked polyethylene and radiation crosslinked polypropylene. 12. The non-crosslinked thermoplastic resin is selected from non-crosslinked polyethylene and poly 1-butene having an isotactic structure. The resin pipe joint according to any one of claims 1 to 11, comprising one resin. 13. The joint body according to claim 1, wherein the tubular body of the joint body has one form selected from a single form of a straight pipe and a bent pipe, and a composite form of a T-shaped pipe. Resin pipe fitting.