JPH06265083A - Electric fusion pipe coupling, joining method therefor, and anti-slip-off member used therefor - Google Patents

Abstract

PURPOSE:To provide an EF coupling and a joining method for the EF couplings wherein problems regarding a tool for fixing the EF coupling are dissolved, a work time can be shortened, there is no need to prepare a number of tools for a work during a fusion joining work, and a trouble required for recovery of the tool after cooling is eliminated. CONSTITUTION:An EF coupling comprises a pipe coupling body 3 made of thermoplastic resin; a plurality of connection holes 5 formed in the pipe coupling body; an electric member 7 laid on the pipe coupling body 3 along the inner surface of the connection hole; and an anti-slip-off member 21 having a taper- form stiffener part 23 inserted between the inner surface of the connection hole 5 and the outer surface of a plastic pipe 11. Since the EF coupling and the plastic pipe are fixed together through the wedge effect of the anti-slip-off member, there is no need for the tool for fixing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric fusion (electrofusion) pipe joint for joining a thermoplastic pipe such as a polyethylene pipe for gas and water by electric heat fusion, a joining method therefor, and a retainer used therefor. Regarding members. In particular, an electric fusion tube improved by including a retaining member having a wedge effect, which is inserted between the inner surface of the connection hole of the pipe joint and the outer surface of the plastic pipe, and which does not require a pipe fixing tool at the time of joining work. The present invention relates to a joint (hereinafter referred to as an EF joint), a joining method thereof, and the like.

[0002]

2. Description of the Related Art FIG. 8 is a perspective view showing a welding work situation of a conventional EF joint. The EF joint 81 is a tubular body made of a thermoplastic (polyethylene, polybutene, etc.), and has a connection hole 82 formed (opened). Along the inner surface of the connection hole 82, a heating wire is embedded within the fitting body, similar to that found in the EF fitting of the present invention of FIG. When a tube (polyethylene tube) 83 made of the same material is inserted into the connection hole 82 and then this heating wire is energized, the heating wire generates heat due to Joule heat and melts the surrounding polyethylene (melting point about 130 ° C.) to The pipe 83 and the pipe 83 ′ are formed by integrating the pipe joint 81.
Join with.

During this joining operation, the pipe 83 and the pipe 83 'to be joined are fixed by the fixing tool 85. During fusion and subsequent cooling (until the resin is completely solidified),
This is to prevent the pipes 83 and 83 'from coming out of the EF joint 81. If the pipes are misaligned in the pipe joint during joining work,
A defect may occur in the fusion-bonded portion, and the long-term life of the bonded portion may deteriorate. Therefore, this fixing has a great influence on the success or failure of the joining work.

The conventional fixing tool 85 has two sets of clamp arms 86 for holding the outer surface of the pipe 83 protruding from the connection hole 82 of the EF joint 81 on the left and right. After sandwiching the pipe 83 with the clamp arm 86, the tightening handle 87
Is turned to clamp and fix the clamp arm 86. The shape and dimensions of the fixing tool differ depending on the size of the joint or pipe and the type of joint. The EF joint 81 shown in FIG. 8 is a straight pipe type (socket) joint, and the EF joint 91 shown in FIG. 9 is an elbow type. The elbow fixing tool 95 shown in FIG. 9 has a polyethylene pipe 93 that intersects at an angle of 90 °.
It is structured so that it can be grabbed and fixed. The fixing tool is generally made of aluminum alloy, and in the case of a fixing tool for sockets that can also be used for 50A and 75A pipes, the weight per piece is about 2 kg,
The price is about 50,000 yen.

[0005]

The conventional EF joint fusion work using a fixing tool has the following problems. Depending on the type of joint (socket, elbow, cheese, etc.) and size, we had to prepare various types of fixing tools. Until cooling of EF joint is completed (10 to 25 minutes)
Since the tools cannot be removed, it was necessary to prepare a large number of fixing tools of the same type and size when joining a large number of places at the same time. Or, the next work had to be waited until the cooling was completed. In particular, in the case of the construction of piping buried in the road, even when it is desired to refill the road immediately after the fusing work, the time for cooling and collecting the tools has to be waited, and the road traffic is interrupted for a long time.

It takes a lot of time to collect the fixing tool after cooling. In order to reduce the weight of the tool, the tool is made of high-strength aluminum alloy casting, but since this material is relatively weak against impact, it sometimes cracked when dropped. In that case, in the worst case, the construction had to be stopped.

The present invention solves the above problems relating to the tool for fixing the EF joint, shortens the construction time, does not need to prepare a large number of work tools at the time of fusion bonding work, and collects the tools after cooling. An object of the present invention is to provide a labor-saving EF joint, a method for joining the joint, and a retaining member used for the joint.

[0008]

The electric fusion pipe joint of the present invention is an electric fusion pipe joint for joining a plurality of thermoplastic pipes by electric heating fusion, and is a thermoplastic pipe joint body. A plurality of connection holes formed in the pipe joint body, an electric heating member laid along the inner surface of the connection hole, and a tapered shape inserted between the inner surface of the connection hole and the outer surface of the plastic pipe. And a retaining member having a stiffener portion.

Here, the "electrical heating member embedded in the pipe joint body" is a member such as a heating wire, an electric heating film, a conductive resin layer or the like that generates heat when energized, and the whole or a part of the pipe joint. It means a member that is embedded or attached to the inside of the body. Any material, structure, and installation method may be used as long as it can sufficiently realize the electric fusion function of the electric fusion pipe joint.

The taper-shaped stiffener portion of the retaining member may have a tapered tubular shape such that it is entirely inserted between the inner surface of the pipe joint connection hole and the outer surface of the plastic pipe, but the portion between them is small. It may be a wedge-shaped piece to be inserted. On the surface of the stiffener portion, in order to enhance the retaining effect, it may be provided with a notch or a barb-like projection of a fishing hook.

In another embodiment, the electric fusion pipe joint of the present invention is an electric fusion pipe joint for joining a plurality of thermoplastic pipes by electric heating fusion, and a pipe joint body made of a thermoplastic resin. A portion of the pipe joint body having a plurality of connection holes and an electric heating member provided along the inner surface of the connection hole, wherein the electric heating member is not provided on the inner surface of the portion near the inlet of the connection hole. (Inlet cold zone)
Has a tapered inner surface of the connection hole that spreads toward the inlet,
By inserting a retaining member that exhibits a wedge effect between the tapered portion and the outer surface of the plastic pipe, it is possible to prevent the plastic pipe from coming out of the pipe joint.

The tapered portion may be provided over the entire circumference of the inner surface of the pipe joint connection hole. It may be provided partially (in the shape of a groove). The retaining member that exhibits the wedge effect does not need to taper the insertion portion itself, but it may be tapered. The knurls and the like on the surface of the insertion portion are the same as those of the above-mentioned stiffener portion.

A method of joining an electric fusion pipe joint according to the present invention comprises a pipe joint body made of a thermoplastic, a plurality of connection holes formed in the pipe joint body, and the inner surface of the connection hole. A method for joining a thermoplastic pipe using an electric fusion pipe joint comprising:
The plastic pipe inserted into the pipe joint exhibits a wedge effect between the inner surface of the connection hole and the outer surface of the plastic pipe in order to prevent the plastic pipe from coming out of the pipe joint during electric fusion and subsequent cooling. It is characterized in that a retaining member for preventing the insertion is inserted.

The taper of the stiffener portion of the retaining member or the taper portion of the inner surface of the pipe joint connecting hole is not particularly limited numerically, but is 1/1
It may be from 00 to 7/100.

[Operation] After inserting the plastic pipe into the pipe joint connection hole,
Before starting the electric fusion, it is necessary to fix the pipe joint and the plastic pipe so as not to shift. In the present invention, the retaining member having the wedge effect is inserted (inserted) between the inner surface of the pipe joint connection hole and the outer surface of the plastic pipe, and the both are fixed so as not to be displaced. In order to obtain the wedge effect, a tapered member may be inserted between both parallel gaps, or both gaps may be tapered,
You may insert a parallel member there. Both members and gaps,
It may be tapered. After mounting the retaining member, the pipe joint and the plastic pipe are electrically fused. Since the retaining member has a simple structure and can be manufactured at low cost, it can be left attached to the pipe joint. Therefore, it is not necessary to remove the pipe joint after waiting for the electric fusion portion to cool.

The retaining member used in the present invention is provided with an insertion portion and a flange portion following the insertion portion, which is used when the retaining member is inserted between the inner surface of the pipe joint connecting hole and the outer surface of the plastic pipe. It is preferable that the flange portion is in contact with the pipe joint end surface to determine the deepest insertion limit of the retaining member, and at the time of this deepest insertion, the tip of the retaining member insertion portion is in the cold zone of the pipe joint connecting hole.

When inserting the retaining member, the flange portion can be pushed with a finger or hit with a hammer. Further, when the retaining member is inserted, the end face of the flange portion comes into contact with the end face of the pipe joint, and the retaining member cannot be inserted deeper (becomes a stopper). At such time, the tip of the insertion part of the retaining member is in the cold zone of the pipe joint connection hole, that is, the entire insertion part stays in the cold zone and does not reach the electric heating member installation part (hot zone). Is preferred. This is because dust may be brought into the hot zone or extra boundary surfaces may be added, which may adversely affect the joining quality.

In one aspect, the retaining member of the present invention comprises a plurality of insert pieces, a flange erected at one end of the insert pieces, and a connecting portion connecting the insert pieces and the insert pieces in series. Then, between the inner surface of the electric fusion pipe joint connection hole and the outer surface of the plastic pipe to be inserted into the abutment connection hole, the above-mentioned insert piece, while keeping the interval determined by the connecting portion, by pressing the flange, and inserting. The plastic pipe can be prevented from coming out of the pipe joint during the electric fusion and the subsequent cooling. The details will be described in Examples.

According to another aspect of the retaining member of the present invention, the connecting portion of the retaining member is flexible and is connected in a C-shape as a whole, and the retaining member has a certain dimensional difference. The retaining member can also be wound around the pipe. The details will be described in Examples.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will be given below with reference to the accompanying drawings. Figure 1
FIG. 3 is a cross-sectional view showing a structure of an electric fusion pipe joint according to an embodiment of the present invention. The pipe joint body 3 of the electric fusion pipe joint 1 has a tubular shape as a whole, and its internal space serves as a connection hole 5 into which the end of the polyethylene pipe 11 is inserted. On the inner surface of the connection hole 5, along the same surface, a coil-shaped heating wire 7 as an electric heating member is embedded in the pipe joint body 3.
0.1 mm between the inner diameter of the heating wire 7 and the inner surface of the connection hole 5.
There is a resin layer (a part of the main body) having an order of thickness. The heating wire 7 is connected to a terminal 9 provided on the outer surface of the pipe joint, and power is supplied from a connection terminal connected to the terminal.

A stopper 6 is provided in the inner part of the connection hole 5 so as to project to the inner surface of the connection hole, and the end surface of the polyethylene pipe 11 inserted into the stopper 6 comes into contact with the stopper 6 to position the same. On the inner surface near the entrance of the connection hole 5,
Area where heating wire 7 is not buried (cold zone 8)
Exists. This portion hardly rises in temperature even during electric fusion and does not melt. The resin melted in the hot zone flows into this cold zone and hardens, so that it does not come out of the pipe joint.

The stiffener portion 23 of the retaining member 21
Has a plate-like shape (insertion piece) with a tapered cross section, and is inserted into the gap between the inner surface of the connecting hole 5 and the outer surface of the polyethylene pipe 11 from the inlet of the connecting hole 5. A flange 25 is provided at one end of the stiffener portion 23 of the retaining member 21 (the left side of the drawing, the thicker stiffener). The end surface of the flange 25 on the stiffener side is in contact with the end surface 4 of the pipe joint body, so that the retaining member 21 cannot be inserted further inward in the connection hole. At this time, the tip 24 of the stiffener portion 23 in the driving direction remains within the cold zone 8.

FIG. 2 shows a retaining member 21 of the embodiment shown in FIG.
It is a perspective view showing. FIG. 3 is a front view of the retaining member of the embodiment of FIG. 4 is a cross-sectional view of the insertion piece 23 of the retaining member of FIG. 2 as seen in the AA direction of FIG.

In FIG. 2, the retaining member 21 includes five insert pieces 23 forming a stiffener portion and a flange 25.
And a connecting portion 27. The insertion piece 25 has a plate-like shape and, as shown in FIG. 4, has a taper shape that gradually becomes thinner from a root portion (right side in the drawing) connected to the flange 25 toward the tip portion 24. Are doing All the five insertion pieces have the same shape, and are vertically arranged on a circumference of a circle at a predetermined interval so as to be substantially upright from the circle.

At the base of the insertion piece 23, a flange 25 which is raised at a right angle to the longitudinal direction of the insertion piece 2 is provided.
It is provided by connecting to 5. The flange 25 is a portion that can be manually pushed or tapped with a plastic hammer or the like when the insertion piece 23 is inserted (pushed) between the pipe joint connection hole and the polyethylene pipe. Further, the end surface 29 of the flange 25 on the insertion piece 23 side comes into contact with the end surface of the pipe joint body so that the insertion piece cannot be pushed further deeper.

The connecting portion 27 is a member for connecting the flanges 25 (therefore, the insertion pieces 23), and has a C-shaped ring shape with a part cut out as a whole. If the retaining members were five disjoint members composed only of the insert piece 23 and the flange 25, they could be inserted between the pipe joint connection hole and the polyethylene pipe at appropriate equal intervals. It will require some caution. On the contrary,
If there is a connecting portion 27, without paying such attention,
The insertion piece 23 can be properly arranged on the circumference.

The connecting portion 27 is not in the form of a perfect ring (closed circle), but is partially cut away.
Further, the width (thickness in the radial direction) of the connecting portion 27 is narrower than the width of the flange 25, and the connecting portion can be bent to widen or narrow the C-shaped notch. Therefore, the polyethylene pipe having a slightly different diameter can be attached (wound) to the outer periphery of the polyethylene pipe in a tightly wound state.

The retaining member of this embodiment can be manufactured by injection molding of plastic or sheet metal working of steel plate. As an example of the dimensions of the insertion piece 23, a nominal diameter 50A
For polyethylene pipes, the wall thickness of the insert tip is 0.2 m
With the m, the taper 2/100, and the insertion length of 20 mm, the predetermined purpose could be achieved. By the way, the inner diameter of the pipe joint connection hole at this time was 60.5 mm, the outer diameter of the polyethylene pipe was 59.6 mm (after peeling cutting), and the gap was 0.
It was 45 mm.

FIG. 5 is a side view showing a retaining member 31 according to another embodiment of the present invention. The insertion piece 33 of the retaining member 31 has a substantially rectangular plate shape (spatular shape) of the same thickness. One end (tip 34) thereof is slightly pointed so that it can be easily inserted into the gap. A large number of barb projections 39 are provided upright on the upper and lower surfaces of the insertion piece 33. The barb protrusion 39 has a triangular side surface shape like a shark's dorsal fin and has a gentle slope in the insertion direction of the insertion piece, so that the insertion piece can be inserted, but the insertion piece can be pulled out. In the direction, the corners of the barb projections 39 cut into the surface of the object forming the gap to be inserted, so that it is difficult to pull out the insertion piece.

A rising portion 35 is provided on the side opposite to the tip of the insertion piece 33.
Are connected so as to rise from the insertion piece 33 at a substantially right angle. The rising portion 35 has the same function as the flange 25 of the retaining member 21 shown in FIGS. The retaining member of the embodiment of FIG. 5 has a shape suitable for manufacturing by sheet metal pressing of steel.

FIG. 6 is a sectional view showing a state where the retaining member 31 of FIG. 5 is inserted between the pipe joint body 3 and the polyethylene pipe 11. FIG. 7 is a cross-sectional view showing a BB cross section of FIG. 6. The insertion piece 33 of the retaining member is inserted between the inner surface of the connection hole 5 of the pipe joint body 3 and the outer surface of the polyethylene pipe 11, and the barb projections 39 on the upper and lower surfaces of the insertion piece 33.
However, it bites into the inner surface of the connection hole 5 and the outer surface of the polyethylene pipe 11 to fix the polyethylene pipe 11 to the pipe joint body 3.

As shown in FIG. 7, the pipe joint body 3
A concave pocket 41 for accommodating the insertion piece 33 of the retaining member 31 is provided in some places on the inner surface of the. The pocket 41 is formed like a groove extending inward from the end surface 4 of the pipe joint body 3 to the inner surface of the connection hole 5. The groove is tapered so that the end face is deepest and becomes shallower as it goes deeper.

The pipe joint body 3 and the polyethylene pipe 11 can be fixed by inserting the insertion piece 33 of the retaining member into the pocket 41. The advantage of the pocket method is that even if the difference (skimmer) between the inner diameter of the pipe joint body connection hole and the outer diameter of the polyethylene pipe is narrow, it is possible to insert a retaining member insertion piece having a certain thickness. Further, by providing pockets at predetermined positions on the circumference of the end face of the pipe joint body, the retaining members can be naturally inserted at even intervals.

[0034]

As is apparent from the above description, the electric fusion splicing joint of the present invention exhibits the following effects. Since the same retaining member can be used regardless of the type of joint (socket, elbow, etc.), or in some cases, regardless of the size of the joint / pipe, it is not necessary to prepare many types of fixing tools.

Since it is not necessary to collect the retaining member even after the electric fusion of the joint, there is no adverse effect such that the work proceeds while waiting for the electric fusion zone to cool. In the case of road excavation work, the pipe assembly can be backfilled as soon as electric fusion is completed. No expensive and breakable tools are required. As a result of the above, it is extremely important to contribute to the speedup and labor saving of piping work for gas and water.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a structure of an electric fusion pipe joint according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a retaining member 21 of the embodiment shown in FIG.

3 is a front view of the retaining member of the embodiment of FIG. 1. FIG.

4 is a perspective view of the insertion piece 23 of the retaining member shown in FIG.
It is sectional drawing seen in the -A direction.

FIG. 5 is a retaining member 31 according to another embodiment of the present invention.
It is a side view showing.

6 is a sectional view showing a state in which the retaining member 31 of FIG. 5 is inserted between the pipe joint body 3 and the polyethylene pipe 11. FIG.

7 is a cross-sectional view showing a BB cross section of FIG.

FIG. 8 is a perspective view showing a joining work situation of a conventional EF joint.

FIG. 9 is a plan view showing a conventional elbow type EF joint and a fixing jig.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Electrofusion pipe joint 3 Pipe joint main body 4 Pipe joint end surface 5 Connection hole 6 Stopper 7 Heating wire 8 Cold zone 9 Terminal 11 Polyethylene pipe 21 Fall prevention member 23 Stiffener part (insertion piece) 24 Stiffener tip 25 Flange 27 Connection part 29 End face 31 Detachment prevention member 33 Insertion piece 34 Insertion piece tip 35 Start-up part 39 Barb protrusion 41 Pocket 81 Electrofusion pipe joint 82 Connection hole 83 Polyethylene pipe 85 Fixing tool 86 Clamp arm 87 Clamping handle 91 Elbow type electrofusion pipe Fitting 93 Polyethylene pipe 95 Fixing tool for elbow

Claims (9)

[Claims] 1. An electric fusion pipe joint for joining a plurality of thermoplastic pipes by electric heat fusion; a thermoplastic pipe joint body, and a plurality of connections formed in the pipe joint body. A hole, an electric heating member laid along the inner surface of the connection hole, and a retaining member having a tapered stiffener portion inserted between the inner surface of the connection hole and the outer surface of the plastic pipe. Characteristic electric fusion pipe joint. 2. An electric fusion pipe joint for joining a plurality of thermoplastic pipes by electric heat fusion; a thermoplastic pipe joint body, and a plurality of connections formed in the pipe joint body. A connection part, which comprises a hole and an electric heating member laid along the inner surface of the connection hole, and a portion of the inner surface near the inlet of the connection hole where the electric heating member is not installed (inlet cold zone) spreads toward the inlet. It is possible to prevent the plastic pipe from coming out of the pipe joint by having a tapered portion on the inner surface of the hole and by inserting a retaining member that exhibits a wedge effect between the tapered portion and the outer surface of the plastic pipe. An electric fusion pipe joint characterized in that 3. An electric fusion bond, comprising: a pipe joint body made of thermoplastics; a plurality of connection holes formed in the pipe joint body; and an electric heating member laid along the inner surface of the connection hole. A method of joining thermoplastic pipes using a pipe joint; for preventing the plastic pipe inserted into the pipe joint from coming out of the pipe joint during electrofusion and subsequent cooling. A method for joining an electric fusion pipe joint, characterized in that a retaining member having a wedge effect is inserted between the inner surface of the connection hole and the outer surface of the plastic pipe. 4. The retaining member is provided with an insertion portion and a flange portion following the insertion portion. When the retaining member is inserted between the inner surface of the pipe joint connection hole and the outer surface of the plastic pipe, the flange portion is provided. Is in contact with the pipe joint end face to determine the deepest insertion limit of the retaining member, and at the time of this deepest insertion, the tip of the retaining member inserting portion is in the cold zone of the pipe joint connecting hole. An electric fusion pipe joint or a method for joining the electric fusion pipe joint according to claim 1. 5. The taper of the stiffener part of the retaining member or the taper of the taper part of the inner surface of the pipe joint connecting hole is 1/100 to 7/100. A method for joining an electric fusion pipe joint or an electric fusion pipe joint. 6. A plurality of insert pieces, a flange erected at one end of the insert pieces, and a connecting portion that connects the insert pieces to each other in series;
Between the inner surface of the electric fusion pipe joint connection hole and the outer surface of the plastic pipe to be inserted into the contact connection hole, the insert piece is inserted by pressing the flange while leaving a space defined by the connecting portion, thereby the plastic A retaining member for an electric fusion pipe joint, characterized in that the pipe can be prevented from coming out of the pipe joint during the electric fusion and the subsequent cooling. 7. The retaining member is flexible and has a C-shaped coupling as a whole, and the retaining member is also wound around a plastic pipe having a certain dimensional difference. The retainer member for an electric fusion pipe joint according to claim 6, which can be formed. 8. A spatula-shaped insert piece, and a rising part provided upright at the rear end of the insert piece; a protrusion provided on the surface of the insert piece to enhance the wedge effect of the insert piece. A retaining member for an electric fusion pipe joint, which is characterized by being provided. 9. The taper portion on the inner surface of the connection hole is not provided all around the entrance portion of the connection hole, but in some places,
The electric fusion splicing joint according to claim 2, which is provided in a pocket shape like a groove extending from the end face of the pipe joint body to the inside of the connection hole.