JP4603680B2 - Welding confirmation method for thermoplastic resin pipe joints - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for confirming a welded connection of a pipe joint made of thermoplastic resin, and more specifically, on the outer peripheral surface of the insertion port of the thermoplastic resin connection pipe or the inner peripheral surface of the receptacle of the thermoplastic resin connection pipe. A heating wire is wound along the circumferential direction, and after inserting the connection tube outlet into the receiving port of the connected tube, the connecting wire and the connecting tube are integrally welded and connected by energizing the heating wire. It relates to a method for confirming the welded connection of pipe joints used for water and sewer pipes. In particular, pipe joints of φ200mm to φ2000mm or more are targeted.
[0002]
[Prior art]
Conventionally, a method for confirming the welded state of an electric 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 a synthetic resin pipe joint having a small diameter, particularly φ200 or less, there is generally a specification example of a socket type joint. In other words, the welding confirmation method is a method in which a pin-like object is insert-molded when molding the socket, and if the pin is raised by the expansion of the resin from the inner surface during welding, the energization to the heating wire is completed. It was.
[0003]
[Problems to be solved by the invention]
However, in the conventional technology, as described above, since it is a method of confirming by the rising of the thermoplastic resin from the inner surface, it is necessary to be surely raised, but a large-diameter pipe joint is a small-diameter Unlike pipe joints, the thickness of the pipe is very large, so it was very difficult to make a quantitative judgment based on the rise of the thermoplastic resin. Moreover, since a large diameter resin pipe is usually extrusion molding, insert molding is difficult.
[0004]
[Means for Solving the Problems]
The present invention relates to a pipe to be connected after winding a heating wire along the circumferential direction on the outer peripheral surface of the outlet of the connecting pipe made of thermoplastic resin or the inner peripheral face of the receiving pipe of the connecting pipe made of thermoplastic resin. When the connecting pipe and the connected pipe are integrally welded and connected by inserting the connecting pipe outlet into the receiving hole and then energizing the heating wire, a small hole is previously drilled in the receiving pipe of the connected pipe, After energizing the heating wire, a process of confirming the completion of the welding connection between the connecting pipe and the connected pipe by pushing a thin rod through the small hole and biting into the outlet of the connecting pipe at a predetermined depth or more , The connection pipe, the pipe to be connected, and the thin rod are formed of the same thermoplastic resin, and a welded connection confirmation method for a thermoplastic resin pipe joint is provided.
[0005]
That is, according to the present invention, when the connecting pipe and the connected pipe are welded and connected integrally, a small hole is formed in advance in the receiving port of the connected pipe, and after passing through the heating wire, the thin rod is inserted through the small hole. It is intended to confirm the completion of the welded connection between the connecting pipe and the connected pipe by pushing in and inserting into the outlet of the connecting pipe at a predetermined depth or more. And, the welded connection of the connecting pipe can be confirmed nondestructively.
[0006]
That is, for example, the depth direction in which complete welding (fusion) is performed from the position of the heating wire wound on the inner surface of the receiving port of the connected tube or the outer surface of the connecting tube toward the center of both connecting tubes. Is measured in advance for each product, and a value that cannot be pushed in unless melted is set as a predetermined depth of biting. For example, in the case of a pipe joint having a diameter of about 200 mm, the predetermined depth of the connected pipe is 4 to 10 mm, preferably 6 mm.
[0007]
Specifically, the small hole is a through hole having a diameter of 3 to 5 mm, the thin rod is 2.8 to 4.8 mm in diameter, and the length is a predetermined depth corresponding to the thickness of the connected pipe (depth of the small hole). If this value is added, it is only necessary to push the thin rod (preferably made of the same thermoplastic resin as both connecting pipes) to the position of the uniform surface on the outer surface of the mouth, and melt the resin near the heating wire. The state can be easily judged, and the pressed-in thin bar is integrated with the molten thermoplastic resin in the vicinity, and it can be maintained as it is without affecting the welded connection even after confirmation of the welded connection. . Preferably, a thin rod having a slightly smaller diameter than the small hole diameter is used.
[0008]
According to another aspect of the present invention, there is provided a thermoplastic resin connecting pipe having an insertion opening and a receiving opening for receiving the insertion opening of the connecting pipe, and a thermoplastic having a small hole previously formed in the receiving opening. It is wound along the circumferential direction on the inner peripheral surface of the connecting pipe made of resin and the receiving port of the connecting pipe or the outer peripheral surface of the connecting pipe, and the connecting pipe is inserted into the receiving port of the connecting pipe. After inserting, the heating wire that welds and connects the connecting pipe and the connected pipe together by energization, and after energizing this heating wire, it is pushed through the small hole and inserted into the outlet of the connecting pipe to a predetermined depth or more. the Ri Do and a welding connection confirmation wand, said connection tube and the connection tube and the rods, provides a thermoplastic resin pipe joint made of formed of the same thermoplastic resin.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the welding connection confirmation method of the pipe joint made of thermoplastic resin according to the present invention will be described in detail based on the embodiments shown in the drawings. Note that the present invention is not limited thereby.
[0010]
FIG. 1 is a perspective view showing a state before connection of a thermoplastic resin pipe joint for explaining a welding connection confirmation method for 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 port, and FIG. 3 is a perspective view showing a thermoplastic resin cylindrical rod as a thin rod used as an index for welding connection in the small hole. FIG. 4 is a cross-sectional view of the main part comparing the state in which the insertion of the thin rod is completed when the main part is completely melted (a) and when the incomplete melting is performed (b). Further, FIG. 5 shows a state where the pipe joint is melted as a temperature distribution in a cross-sectional view of the main part.
[0011]
First, in FIG. 1, 1 is a polyethylene pipe as a thermoplastic resin pipe (connecting pipe), 4 is an inlet of the thermoplastic resin pipe 1, and 2 is a thermoplastic resin pipe (connected pipe). The receptacle part of the polyethylene joint 1a is shown. Further, 3 is a heating wire wound around the receiving port 2.
In FIG. 2, a small hole 6 having a diameter of 3 to 5 mm is formed in the receiving portion 5 corresponding to 2 in FIG. The cylindrical hole 7 made of a thermoplastic resin shown in FIG. 3 is pushed into the small hole 6 after completion of energization. Therefore, the thermoplastic resin cylindrical rod 7 is preferably designed to be slightly smaller than the diameter of the small hole 6.
4a and 4b show examples of different states after completion of energization. The state shown in FIG. 4a is that the receiving port portion 8 of the thermoplastic resin tube and the insertion port portion 9 of the thermoplastic resin tube are fitted, and the heating wire 10 inserted in advance is energized to weld the pipe joint. This shows a case where a predetermined amount of energy is not supplied to the joint portion of the pipe joint after the integration. In this case, the cylindrical rod 7 made of thermoplastic resin cannot be pushed to the position corresponding to the outer surface of the receiving port. However, when the welding is complete, as shown in FIG. 4b, the thermoplastic resin cylindrical rod 11 (corresponding to 7 in FIG. 4a) can be pushed to the same position as the outer surface of the receiving port.
[0012]
The embodiment of the present invention will be described from another point of view. When the thickness of the receiving port 5 of the thermoplastic resin pipe shown in FIG. 2 is tmm, it is shown in FIG. 3 which is formed of a thermoplastic resin equivalent to the base material. The cylindrical rod made of thermoplastic resin as the thin rod is preferably designed to be (t + 6) mm. Immediately after the energization is completed, a thermoplastic resin cylindrical rod is inserted from the outer surface of the receptacle.
As shown in FIG. 5, a thermoplastic resin cylindrical rod 15 designed with (t + 6) mm is inserted into the outlet 17 of a thermoplastic resin pipe to which a portion corresponding to a length of 6 mm is welded. According to this, the temperature distribution in the circumferential direction of the tube from the wound heating wire 18 decreases as the distance from the heating wire portion increases, and in the portion 6 mm away from the heating wire portion in the circumferential direction, the mother The material temperature is 130 ° C to 150 ° C. Therefore, the thermoplastic resin cylindrical rod 15 inserted from the outer surface of the receiving port is designed to be 6 mm longer than the receiving port thickness tmm, and if it can be pushed to the same surface as the outer surface of the receiving port, sufficient welding is performed. This can be easily confirmed. Further, since the cylindrical rod 15 made of thermoplastic resin is made of the same resin as the base material, it is integrated with the pipe after being pushed.
[0013]
【The invention's effect】
According to the present invention, when the connecting pipe and the connected pipe are integrally welded and connected, a small hole is made in advance in the receiving port of the connected pipe, and after passing through the heating wire, the thin rod is inserted through the small hole. It is intended to confirm the completion of the welded connection between the connecting pipe and the connected pipe by pushing in and inserting into the outlet of the connecting pipe at a predetermined depth or more. And, the welded connection of the connecting pipe can be 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 weld connection of a thermoplastic resin pipe joint according to the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part of a receptacle of a thermoplastic resin pipe.
FIG. 3 is a perspective view of a cylindrical rod made of thermoplastic resin.
FIG. 4 is a cross-sectional view of a principal part showing a configuration around a thermoplastic resin cylindrical rod inserted into a receiving portion of a thermoplastic resin pipe.
FIG. 5 is a cross-sectional view of a main part showing a temperature distribution of a cross section of a pipe joint to be welded.
[Explanation of symbols]
1 Polyethylene pipe (thermoplastic resin pipe)
2 Receptacle part 3 Heating wire 4 Insertion part 5 Receptacle part 6 Small hole

Claims (5)

On the outer peripheral surface of the outlet of the thermoplastic resin connecting pipe or the inner peripheral surface of the receiving port of the thermoplastic resin connected pipe, a heating wire is wound along the circumferential direction, and then connected to the receiving port of the connected pipe When connecting the connecting pipe and the pipe to be connected together by welding by inserting the inlet of the pipe and then energizing the heating wire, a small hole is made in advance in the receptacle of the pipe to be connected and the heating wire is energized. Thereafter, a step of checking the completion of the welding connection between the connecting pipe and the connected pipe by pushing a thin rod through the small hole and biting into the inlet of the connecting pipe at a predetermined depth or more , the connecting pipe, A welded connection confirmation method for a pipe joint made of thermoplastic resin, wherein the pipe to be connected and the thin rod are formed of the same thermoplastic resin .   The welding connection confirmation method according to claim 1, wherein the small hole is a through hole having a diameter of 3 to 5 mm.   The welding connection confirmation method according to claim 1 or 2, wherein the predetermined depth of biting is 4 to 10 mm.   The welding connection confirmation method according to any one of claims 1 to 3, wherein the thin rod has a length obtained by adding a predetermined depth that is difficult to make the small hole deep. A thermoplastic resin connecting pipe having an inlet;
A connecting pipe made of a thermoplastic resin having a receiving opening for receiving the insertion opening of the connecting pipe, and having a small hole previously drilled in the receiving opening;
It is wound around the inner peripheral surface of the receiving port of this connected pipe or the outer peripheral surface of the connecting tube's outlet along the circumferential direction. After inserting the connecting port's outlet into the receiving port of the connected pipe, it is connected by energization A heating wire that welds and connects the pipe and the connected pipe together;
After energizing the heating wire, said pushed through a small hole, Ri Do from the connection pipe to insert the mouth with a predetermined depth or bite the welded connection confirmation thin rod of the connecting pipe, the connecting pipe and the rods Are thermoplastic resin pipe joints formed of the same thermoplastic resin .

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