JP2002192622A - Method for confirming welding of pipe joint made of thermoplastic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of simply and certainly confirming the completion of weld connection. SOLUTION: An electric heating wire is wound around the outer peripheral surface of the spigot of a connection pipe made of a thermoplastic resin or the inner peripheral surface of the receiving port of a pipe to be connected made of a thermoplastic resin along the circumferential direction thereof, the spigot of the connection pipe is inserted into the receiving port of the pipe to be connected and, next, a current is supplied to the electric heating wire to integrally connect the connection pipe and the pipe to be connected. In this case, a small hole is preliminarily bored in the receiving port of the pipe to be connected and, after a current is supplied to the electric heating wire, a fine rod is pushed in the receiving port through the small hole and, by the insertion of the fine rod into the spigot of the connection pipe over a predetermined depth or more, the completion of the weld connection of the connection pipe and the pipe to be connected is confirmed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for confirming the welded connection of a pipe joint made of a thermoplastic resin, and more particularly, to the outer peripheral surface of an inlet of a connection pipe made of a thermoplastic resin or a socket of a connection pipe made of a thermoplastic resin. A heating wire is wound on the inner peripheral surface along the circumferential direction, and the connection pipe is inserted into the socket of the connection pipe, and then the heating wire is energized, whereby the connection pipe and the connection pipe are connected. And a method for confirming the welded connection of pipe joints used for water and sewer pipes, etc.
In particular, pipe joints from φ200 mm to φ2000 mm or more are targeted.

[0002]

2. Description of the Related Art Conventionally, a method for confirming the welded state of an electrically welded pipe joint, that is, an electrofusion pipe joint, has not been put to practical use with a large diameter. On the other hand, in the case of small-diameter pipe joints, especially synthetic resin pipe joints having a diameter of 200 or less, there are generally specification examples of socket-type joints. In other words, a method for confirming welding is to insert-mold a pin or the like when molding the socket, and to complete the energization of the heating wire if the pin is raised by expansion of the resin from the inner surface during welding. Was.

[0003]

However, in the prior art, as described above, the method is such that the thermoplastic resin is confirmed by the protrusion of the thermoplastic resin from the inner surface. Unlike a small-diameter pipe joint, a pipe joint having a large diameter has a very large pipe thickness, and therefore, it is very difficult to make a quantitative determination based on the protrusion of the thermoplastic resin. In addition, since a large-diameter resin pipe is usually formed by extrusion, it is difficult to perform insert molding.

[0004]

SUMMARY OF THE INVENTION The present invention provides an electric heating wire along the circumferential direction on the outer peripheral surface of an inlet of a thermoplastic resin connecting pipe or the inner peripheral surface of a receiving port of a thermoplastic resin connecting pipe. After the connection pipe is inserted into the socket of the pipe to be connected, and then the heating wire is energized, the connection pipe and the pipe to be connected are integrally welded and connected. A small hole is drilled in advance, and after the heating wire is energized, a thin rod is pushed through the small hole, and the connection pipe and the connection pipe are welded by biting a predetermined depth or more into the insertion opening of the connection pipe. A method for confirming the welded connection of a thermoplastic resin pipe joint, characterized by confirming the completion of the connection.

That is, according to the present invention, when the connection pipe and the connection pipe are integrally welded and connected to each other, a small hole is previously formed in a socket of the connection pipe, and after a heating wire is energized, the small hole is passed through the small hole. By pushing the thin rod and inserting it into the outlet of the connecting pipe at a predetermined depth or more, it is intended to confirm the completion of the welding connection between the connecting pipe and the connected pipe, so that simply pushing the thin rod The welded connection of the connecting tube can be confirmed nondestructively simply and reliably.

[0006] That is, for example, from the position of the heating wire wound on the inner surface of the receiving port of the connected pipe or the outer surface of the outlet of the connecting pipe, toward the center of both connecting pipes, complete welding (fusion)
The length in the depth direction in which the cutting is performed is measured in advance for each product, and a value that cannot be pushed unless melted is set as a predetermined depth of the biting. For example, caliber 200
In the case of a pipe joint of about mm, the predetermined depth of the
0 mm, preferably 6 mm.

That is, specifically, a small hole is formed with a diameter of 3 to 5 mm.
mm, the diameter of the thin rod is set to 2.8 to 4.8 mm, and the length is set to a value obtained by adding a predetermined depth to the thickness (depth of the small hole) of the connected pipe. It is preferable to use the same thermoplastic resin as both connecting pipes.) Only by performing the work of pushing to the position of the uniform surface on the outer surface of the receiving port, the melting state of the resin near the heating wire can be easily judged, and The rod is integrated with the thermoplastic resin in the vicinity of the melted portion, and the state can be maintained as it is without affecting the welded connection even after confirming the welded connection. Preferably, the rod is slightly smaller than the small hole diameter.

According to another aspect of the present invention, there is provided a connecting pipe made of a thermoplastic resin having an outlet, and a receiving port for receiving the connecting port of the connecting pipe, and a small hole formed in advance in the receiving port. A connecting pipe made of a thermoplastic resin, and a connecting pipe wound around the inner peripheral surface of the receiving port of the connecting pipe or the outer peripheral surface of the insertion port of the connecting pipe along its circumferential direction, and connected to the receiving port of the connecting pipe. After the insertion of the insertion hole, a heating wire for integrally welding and connecting the connection pipe and the connected pipe by energization, and after the heating wire is energized, pushed through the small hole and into the insertion port of the connection pipe at a predetermined depth Provided is a pipe joint made of a thermoplastic resin, which comprises a thin rod for confirming a welded connection inserted therein.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for confirming the welded connection of a thermoplastic resin pipe joint according to the present invention will be described in detail based on an embodiment shown in the drawings. Note that the present invention is not limited by this.

FIG. 1 is a perspective view showing a state before connection of a thermoplastic resin pipe joint for explaining a method for confirming welding connection of a thermoplastic resin pipe joint according to the present invention, and has a receiving port at one end. . FIG. 2 is a cross-sectional view showing a state in which a small hole is formed in the receiving portion, and FIG. 3 is a perspective view showing a thermoplastic resin cylindrical rod as a thin rod used as an index of welding connection in the small hole. FIG. 4 is a cross-sectional view of a main part in which the insertion of the thin rod is completed, comparing the case where the main part is completely melted (a) and the case where the main part is incompletely melted (b). FIG. 5 is a cross-sectional view of a main part showing a state in which the pipe joint is melted as a temperature distribution.

First, in FIG. 1, reference numeral 1 denotes a polyethylene pipe as a thermoplastic resin pipe (connection pipe), 4 denotes an opening of the thermoplastic resin pipe 1, and 2 denotes a thermoplastic resin pipe (connection pipe). ) Represents the socket of the polyethylene joint 1a. Reference numeral 3 denotes a heating wire wound around the receptacle 2. In FIG. 2, a small hole 6 having a diameter of 3 to 5 mm is formed in the socket 5 corresponding to 2 in FIG. After the energization is completed, the thermoplastic resin cylindrical rod 7 shown in FIG. Therefore, the thermoplastic resin cylindrical rod 7 may be designed to be slightly smaller than the diameter of the small hole 6. FIGS. 4A and 4B show examples of different states after completion of energization. The condition shown in FIG.
The receiving portion 8 of the thermoplastic resin tube and the insertion portion 9 of the thermoplastic resin tube are fitted, and a heating wire 10 inserted in advance is energized to perform welding and integration of the pipe joint. Is not supplied to the joint of the pipe joint. In this case, the thermoplastic resin cylindrical rod 7 cannot be pushed into a position corresponding to the outer surface of the receptacle. However, when the welding is completely performed, as shown in FIG.
1 (corresponding to 7 in FIG. 4a) can be pushed into a position equivalent to the outer surface of the receptacle.

To explain the embodiment of the present invention from another viewpoint, the thickness of the receiving port 5 of the thermoplastic resin pipe shown in FIG.
mm, the cylindrical rod made of thermoplastic resin as a thin rod shown in FIG. 3 molded with the same thermoplastic resin as the base material is (t
+6) mm is desirable. Immediately after the energization is completed, a thermoplastic cylindrical rod is inserted from the outer surface of the receiving port. As shown in FIG. 5, a thermoplastic resin cylindrical rod 15 designed at (t + 6) mm has an inlet 1 of a thermoplastic resin pipe to which a portion corresponding to a length of 6 mm is welded.
7 is inserted. According to this, the temperature distribution in the circumferential direction of the pipe from the wound heating wire 18 decreases as the distance from the heating wire portion increases, and the temperature distribution decreases by 6 mm in the circumferential direction from the heating wire portion. The material temperature is between 130 ° C and 150 ° C. Therefore, the cylindrical rod 15 made of thermoplastic resin inserted from the outer surface of the receiving port has a thickness of 6 mm from the receiving port thickness tmm.
If it is designed to be mm long and can be pushed down to the same level as the outer surface of the receptacle, it can be easily confirmed that sufficient welding has been performed. Furthermore, since the thermoplastic resin cylindrical rod 15 pushed in is made of the same resin as the base material, it is integrated with the pipe after pushing.

[0013]

According to the present invention, when the connection pipe and the connection pipe are integrally welded and connected to each other, a small hole is previously drilled in the socket of the connection pipe, and after the heating wire is energized, the small hole is closed. A thin rod is pushed into the connection pipe to check the completion of the welded connection between the connection pipe and the connected pipe by biting the connection pipe into the outlet at a predetermined depth or more. In this way, the welded connection of the connection pipe can be simply and reliably confirmed nondestructively.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state before connection of a thermoplastic resin pipe joint for explaining a method for confirming welding connection of a thermoplastic resin pipe joint according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of a receiving port of a thermoplastic resin pipe.

FIG. 3 is a perspective view of a cylindrical rod made of a thermoplastic resin.

FIG. 4 is a cross-sectional view of a main part showing a configuration around a thermoplastic resin cylindrical rod inserted into a receiving portion of a thermoplastic resin tube.

FIG. 5 is a cross-sectional view of a main part showing a temperature distribution of a cross section where the pipe joint is welded.

[Explanation of symbols]

 Reference Signs List 1 polyethylene pipe (thermoplastic resin pipe) 2 receptacle 3 heating wire 4 outlet 5 receptacle 6 small hole

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H019 GA02 GA12 4F211 AD05 AD12 AG03 AG08 AH11 TA01 TC11 TD11 TH20 TN18 TN31 TW39

Claims (6)

[Claims] 1. A heating wire is wound along the circumferential direction on the outer peripheral surface of an inlet of a thermoplastic resin connecting pipe or the inner peripheral surface of a receiving port of a thermoplastic resin connecting pipe, and then connected. When the connection pipe is inserted into the socket of the pipe, and then the heating wire is energized, the connection pipe and the pipe to be connected are welded together to form a small hole in the socket of the pipe to be connected in advance. After energizing the heating wire, a thin rod is pushed in through the small hole, and the completion of the welding connection between the connection pipe and the connected pipe is confirmed by biting a predetermined depth or more into the mouth of the connection pipe. To check the welded connection of thermoplastic resin pipe joints. 2. The method according to claim 1, wherein the small holes are through holes having a diameter of 3 to 5 mm. 3. The method according to claim 1, wherein the predetermined depth of the penetration is 4 to 10 mm. 4. The method for confirming welding connection according to claim 1, wherein the thin rod has a length obtained by adding a predetermined depth of the small hole. 5. The connection pipe according to claim 1, wherein the connection pipe, the connection pipe, and the thin rod are formed of the same thermoplastic resin.
The welding connection confirmation method described in (1). 6. A connecting pipe made of a thermoplastic resin having an inlet, a connecting pipe made of a thermoplastic resin having a receiving port for receiving the connecting port of the connecting pipe, and having a small hole formed in the receiving port in advance. It is wound along the circumferential direction on the inner peripheral surface of the socket of the connected pipe or the outer peripheral surface of the socket of the connecting pipe, and after inserting the socket of the connecting pipe into the socket of the connected pipe, A heating wire for integrally welding and connecting the connecting pipe and the connected pipe; and a welding connection check which is pushed through the small hole after being energized to the heating wire and inserted into the opening of the connecting pipe at a predetermined depth or more. Thermoplastic pipe joint consisting of a thin rod.