JP2003307293A - Pipe line connection technique - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pipe line connection technique securing air tightness between connection surfaces and permitting connection by a simple manner without a complex connecting structure or a large facility. <P>SOLUTION: In this pipe line connection technique when polyethylene pipes 1, 1' are connected with each other or a branch is formed, recesses 3 are formed at positions opposing each other at part of connecting surfaces of a joint 2 inserted into a connecting position or a branch saddle, and an adhesive resin 6 is filled between the connecting surfaces including the recesses 3. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe connecting method, and more particularly to a pipe connecting method for a synthetic resin pipe such as polyethylene.

[0002]

2. Description of the Related Art Conventionally, as a gas pipe laid under a road, a synthetic resin pipe such as polyethylene may be used instead of a cast iron pipe or a steel pipe. This is because the flexural deformation is allowed to some extent with respect to an external force generated at the time of a disaster such as an earthquake to make it hard to be damaged. When a polyethylene pipe is used, a branching part may be provided in a part of the polyethylene pipe or a jointing process may be performed using an electrofusion joint (for example, JP-A-11-3441).
91 publication). This method is equipped with a heat source such as a nichrome wire in the branch saddle when forming a branch, and in the joint where the ends of the pipes are inserted when adding pipes. Then, the inner peripheral surface of the branch saddle or joint and the outer peripheral surface of the polyethylene pipe are fused by heat generated when the heat source is energized.

[0003]

SUMMARY OF THE INVENTION The pipe connection method by electrofusion has the following problems. First, since it is necessary to equip a heat source, the joints used for connection and the branch saddle itself have a complicated structure, which may increase costs. Secondly, at the time of bonding, if an oxide film or the like is present on the surfaces to be bonded, it will be difficult to fuse, so pre-preparation such as scraper treatment for removing the oxide film is required, and the number of work steps is reduced. It may increase. Further, as such a treatment, there is a primer treatment for reducing the difference in the wettability of the adhesive with respect to the target material and for surface protection. In order to solve such a problem, in the above publication, an adhesive resin made of an ethylene-acrylic acid ester copolymer resin is interposed between the bonding surfaces instead of performing a scraper treatment, and the adhesive resin is used as an intermediate layer. A method has been proposed in which the bonding surfaces are fused together. However, the material used as the adhesive resin including the primer treatment is influenced by the material to be joined, so that the selection range is narrow and the cost is increased. In addition, even when the adhesive resin as disclosed in the above-mentioned publication is interposed, since the joining by electrofusion is a prerequisite,
It does not solve the second problem. Third
In addition, since it is necessary to change the amount of heat generation depending on the area of the joint surface and the wall thickness of the pipeline, electrical safety treatment may be required when increasing the power supplied to the heat source, and the equipment is large. There is a risk that it will turn into.

The object of the present invention is to eliminate the problems of the conventional pipe connection method, particularly the connection method using electrofusion, without making the structure of the apparatus used for joining complicated and increasing the size of the equipment. It is an object of the present invention to provide a conduit connection construction method capable of ensuring the airtightness of the joint surfaces and capable of joining by a simple method.

The invention according to claim 1 relates to a pipe connecting method for forming a joint or a branch portion between polyethylene pipes, which is a part of a joint surface of a joint or a branch saddle to be fitted at a joint position. It is characterized in that recesses are formed at positions facing each other, and an adhesive resin is filled between joint surfaces including the recesses.

According to a second aspect of the present invention, in addition to the first aspect of the invention, the recesses are formed by using dovetail grooves formed at the same facing portions on the joint surface.

The invention described in claim 3 is characterized in that, in addition to the invention described in claim 1, a material having a natural foaming property is used as the adhesive resin.

The invention according to claim 4 is the invention according to claim 1 or 2.
In addition to the invention described above, in addition to being used as an adhesive portion that adheres to the joint surfaces by being cured, the adhesive resin is used as a shearing reinforcement portion at the joint surface by entering the concave portion. It has a feature.

[0009]

According to the first aspect of the present invention, the joining surfaces can be joined together without using electrofusion simply by filling the adhesive resin between the joining surfaces including the recesses formed in the facing surfaces. The airtightness between the joint surfaces can be ensured by the recess formed between the joint surfaces functioning as a weir, and the joint strength between the joint surfaces is filled with the adhesive resin that contacts the joint surfaces. Can be secured by

According to the second aspect of the present invention, the recess formed in the joint surface is dovetail-shaped so that the peel strength between the joint surfaces can be secured.

According to the third aspect of the invention, since the adhesive resin has a natural foaming property, when it is filled between the joint surfaces, the gap between the joint surfaces can be filled. In particular, foaming increases the volume in the gap between the joint surfaces, thereby improving the adhesion between the joint surfaces.

According to the fourth aspect of the present invention, since the adhesive resin filled between the joint surfaces is used as the shearing reinforcement portion between the joint surfaces in addition to the joint portion obtained by adhering the joint surfaces to each other, the joint is simply joined. Not only the peeling strength due to the adhesive function between the surfaces but also the reinforcing portion against shear fracture at the joint surface can be configured.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the illustrated examples. FIG. 1 is a partial sectional view of a pipeline to which the pipeline connecting method according to this embodiment is applied. In the figure, a polyethylene resin pipe is used for a pipe line 1, and a joint 2 is used for joining another pipe line (denoted by reference numeral 1'for convenience) using a polyethylene pipe to a part thereof. . On the joint surface between the joint 2 and the pipeline 1, 1 ',
As shown in FIG. 1B, at least one concave portion 3 is formed on the facing surface. In the embodiment shown in FIG. 1, the concave portions 3 are formed at the positions facing each other on the joint surface by the same phase.
Are formed. In addition, in FIG.
Shows a loading portion of the O-ring 5 which is formed at a position outside the joint surface and which can ensure airtightness in an auxiliary manner. As for the recessed portion 3, as shown in FIG. 2, it is possible to juxtapose at two locations along the longitudinal direction of the joint surface (indicated by reference numerals 3 and 3'for convenience) or not shown, but it is also possible to juxtapose more than this. Is.

In this embodiment, the pipes 1, 1'and the joint 2 configured as described above are bonded to each other. The adhesive 6 used for bonding has a property capable of spontaneous foaming. An adhesive resin (hereinafter, the adhesive resin is indicated by reference numeral 6) is used. As such an adhesive resin 6, a room temperature curable resin such as an epoxy resin is used as a material forming an adhesive body, and a foaming material having an affinity for the adhesive body is mixed.

The adhesive resin 6 is applied to the joint surfaces of the pipe lines 1 and 1 ′ and the joint 2, and is also filled in the recesses 2. As a result, when the pipe lines 1 and 1'are inserted into the joint 2, the adhesive resin 6 is filled between the joint surfaces. The adhesive resin 6 with which the joint surfaces are filled is naturally foamed to fill the gaps between the joint surfaces and is cured at room temperature.

The cured adhesive resin 6 can be brought into pressure contact with and closely adhered to both joint surfaces by the pressure during foaming, so that the airtightness between the joint surfaces is ensured. Moreover, the airtightness in the laying direction of the pipeline is ensured by the adhesive resin 6 filling the recess 2 forming a weir.
Particularly, at the contact surface between the bonding surface and the adhesive resin 6, the adhesive resin 6
In addition to the adhesion by the suction action of the joints, the joint 2 generated when the joint surface gap is expanded due to the volume expansion between the joint surfaces
The reaction force from the side allows the joint 2 to clamp the pipe lines 1, 1 ′. As a result, the conduits 1 and 1 ′ and the joint 2 can be brought into close contact with each other, so that a firm adhered state can be obtained.

Since the adhesive resin 6 filled in the concave portion 3 is cured to form a radial convex portion of the pipeline, a shear reinforcement portion for preventing relative displacement in the laying direction of the pipeline. Is functioning as. As a result, the peel strength is maintained over the entire joint surface other than the recess.

According to the above-described embodiment, since the joining of the joining surfaces can be performed by a simple operation of applying the adhesive resin 6,
It eliminates the need for large-scale power supply equipment and special structures for joints as in the case of using electrofusion. Moreover, since the adhesiveness between the bonding surfaces can be secured by the curing of the adhesive resin 6, it is possible to eliminate the conventional primer treatment.

Next, a partial modification of the configuration used in the above embodiment will be described. FIG. 3 is a partial cross-sectional view of a pipeline to which the pipeline connection method according to another embodiment is applied. Figure 3
The embodiment shown in is characterized by the shape of the recess. For the sake of convenience, the same members as those shown in FIGS. 1 and 2 in the configuration shown in FIG. In FIG. 3, the recess 30 is not formed in the rectangular shape shown in FIGS. 1 and 2, but is formed by a dovetail groove formed at the same position on the surfaces facing each other.

In the above structure, the adhesive resin 6 is filled between the bonding surfaces by the same procedure as described with reference to FIGS. Between the bonding surfaces, the bonding resin 6 is pressure-contacted and closely adheres to the bonding surface due to volume expansion due to foaming of the bonding resin 6 to bond the bonding surface, and the concave portion 30 is also filled with the bonding resin 6 so that the bonding surfaces face each other. A pair of dovetail-shaped cores are formed between the surfaces. As a result, the bonded surfaces are in a state of being difficult to peel from each other, and the peel strength at the bonded surfaces is kept high. The concave portion 30 is not limited to the dovetail groove shape, but has the same effect as this shape, that is, a shape in which a bulging portion is located inside the pipeline having a joint surface, in other words, a divergent portion is located inside the pipeline surface. If so, it is possible to make it circular or the like. Also, the recesses 3, 3 ',
30 is not limited to the same phase shown in the embodiment,
It is also possible to arrange them in different phases so that the rigidity with respect to the shearing function or the peel strength is different in the joint surface.

[0021]

According to the first aspect of the present invention, the joining surfaces are joined together without using any electrofusion simply by filling the adhesive resin between the joining surfaces including the recesses formed in the facing surfaces. You can Moreover, the airtightness between the joint surfaces can be ensured by the recess formed between the joint surfaces functioning as a weir, and the joint strength between the joint surfaces is filled with the adhesive resin that contacts the joint surfaces. It becomes possible to secure it by bonding.

According to the second aspect of the present invention, since the concave portion formed on the joint surface has a dovetail groove shape, it is possible to secure the peel strength between the joint surfaces.

According to the third aspect of the invention, since the adhesive resin has a natural foaming property, the gap between the joint surfaces can be filled when the adhesive resin is filled between the joint surfaces. In particular, since foaming increases the volume of the gap between the joint surfaces to increase the adhesion between the joint surfaces, it is possible to increase the airtightness between the joint surfaces.

According to the invention of claim 4, since the adhesive resin filled between the joint surfaces is used as a shearing reinforcement portion between the joint surfaces in addition to the joint portion obtained by closely adhering to the joint surfaces. It is possible to provide not only the peeling strength due to the adhesive function between the joint surfaces but also the multi-functionality of forming a reinforcing portion against shear fracture at the joint surfaces.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a configuration of a joint portion used in a pipe joint construction method according to an example for explaining an embodiment of the present invention, FIG. ) Indicates an enlarged cross section of a portion indicated by reference numeral B in (A).

FIG. 2 is a diagram showing a partially modified example of the configuration used for the joint portion shown in FIG. 1, where (A) shows a cross section of the joint portion and (B) shows
Shows an enlarged cross section of a portion indicated by reference numeral B in (A).

FIG. 3 is a diagram showing a partially modified example of the configuration used for the joint portion shown in FIG. 1, where (A) shows a cross section of the joint portion and (B) shows
Shows an enlarged cross section of a portion indicated by reference numeral B in (A).

[Explanation of symbols]

1,1 'pipeline 2 joints 3, 3 ', 30 recess 6 Adhesive resin

Claims (4)

[Claims] 1. A pipe connecting method for forming a joint or a branch portion between polyethylene pipes, wherein at least one recess is provided on a facing surface of a joint surface of a joint or a branch saddle to be fitted at a joint position. A pipe connecting method, which is characterized in that it is formed and an adhesive resin is filled between the joint surfaces including the recesses. 2. The pipeline connecting method according to claim 1, wherein the recesses are formed with dovetail grooves formed at the same facing portions on the joint surface. 3. The pipeline connecting method according to claim 1, wherein the adhesive resin is made of a material having a natural foaming property. 4. The pipe connecting method according to claim 1, wherein the adhesive resin filled between the joint surfaces including the recess is hardened to adhere to the joint surfaces. In addition to being used as a portion, the pipe connecting method is characterized in that it is used as a shearing reinforcement portion at a joint surface by entering into the recess.