JPS61157889A - Composite pipe and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a composite pipe in which an outer pipe such as a hume pipe, a metal pipe, an asbestos pipe, etc. is lined with a synthetic resin inner pipe made of vinyl chloride resin, polyethylene resin, etc. and its manufacturing method.

(Prior art) Composite pipes, in which outer pipes such as hume pipes and metal pipes are lined with synthetic resin inner pipes, have traditionally been used as water and sewage pipes buried underground or as fireproof pipes for sewage in high-rise buildings. ing.

In addition, various methods have been known for manufacturing this composite pipe, and the applicant has previously proposed
In 49@, we proposed the most advanced method for manufacturing composite pipes.

The method for manufacturing this composite pipe will be explained below based on FIGS. 4 and 5.

The outer tube 1-, such as a fume tube or a metal tube, has an enlarged-diameter socket 11' at one end, and a spigot 12' whose diameter is reduced with a step at the other end. A heat-sensitive adhesive is applied to the outer circumferential surface of the outer tube 1' in advance to prevent thermal expansion.
Insert the synthetic resin inner tube 2- into the outer tube 1' by applying the mold 7-1 and the closing plate 8- to the end of the inner tube 2-.
Set.

Next, a heating medium such as steam is introduced into the inner tube 2' to enlarge its diameter, and the inner tube 2- is brought into close contact with the inner peripheral surface of the outer tube 1'.

After that, the mold 7' and the closing plate 8' are removed, and the inner tube 2 is removed.
- is cut at the end of the enlarged diameter socket 11', then the inner mold 9' is press-fitted into the enlarged diameter socket as shown in FIG. It was held close to the surface.

(Problems to be Solved by the Invention) However, this conventional manufacturing method has the disadvantage that it requires a heating medium to heat and expand the synthetic resin inner tube, which requires a large amount of equipment. Increased product costs were inevitable. Furthermore, when a hume tube is used as the outer tube, there is a drawback that the performance of the hume tube is degraded due to the thermal influence of the heating medium.

Moreover, since the composite tube thus obtained has an outer tube and an inner tube with different coefficients of thermal expansion joined together via an adhesive, it is difficult to use this composite tube as a transportation piping for aS fluid. In some cases, the outer or inner tube may be damaged when the inner tube thermally expands in the radial direction.

(Means for Solving the Problems) The present invention solves all of the problems that conventional composite pipes have had, and provides a composite pipe that will not be damaged by heat effects. The present invention provides a method for manufacturing a composite pipe in which the lining process can be performed quickly and reliably without requiring special equipment.

That is, the first invention of the present application has an enlarged diameter socket 11 at one end.
and a spigot 12 at the other end, a receptacle having an outer diameter slightly smaller than the inner diameter of the outer pipe 1, and a socket at one end having an outer diameter slightly smaller than the inner diameter of the enlarged diameter socket 11. An inner tube 1!2 made of synthetic resin having a spout 21 is inserted, and a foaming adhesive 3 is interposed between the outer tube 1 and the inner tube 2, and an outer tube 4 is inserted at the end of the spout 12.
1 and an inner tube 42 are fitted together to cover the outer peripheral surface of the spout 12 with the outer tube 41, and the inner tube 42 is overlapped with the other end of the inner tube 2. It is in a composite pipe.

Further, the second invention provides an outer tube 1 having an enlarged diameter socket 11 at one end and a spigot 12 at the other end, and an outer tube 1 having an outer diameter slightly smaller than the inner diameter of the outer tube 1 and having an outer diameter at one end. A synthetic resin inner tube 2 having a socket 21 with an outer diameter slightly smaller than the inner diameter of the expanded diameter socket 11 is prepared, and an outer tube 41 and an inner tube 42 are formed at the end of the opening 12 of the outer tube 1. While fitting the tube end cap 4, the inner tube 2 is inserted into the outer tube 1 to connect the other end of the inner tube 2 and the inner tube 42.
This method of manufacturing a composite tube is characterized in that the outer tube 1 and the inner tube 2 are joined, and then a foaming adhesive 3 is filled between the outer tube 1 and the inner tube 2.

(Example) Hereinafter, a specific configuration of the present invention will be described in detail based on an example.

Fig. 1 is a longitudinal cross-sectional view of a composite pipe showing one embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view showing the manufacturing process of this composite pipe, and Fig. 3 is a main part showing another embodiment of the present invention. In the cross-sectional view, reference numeral 1 indicates an outer tube such as a hume tube, metal tube, or asbestos tube, 2 indicates an inner tube made of synthetic resin such as vinyl chloride resin, polyethylene resin, polypropylene resin, etc., and 3 indicates a foamable adhesive. , 4 is a tube end cap made of the same kind of synthetic resin material as the inner tube 2.

The outer tube 1 has an enlarged-diameter socket 11 at one end, and a spigot 12 whose diameter is reduced with a step at the other end. A tube end cap 4 is fitted to the end of this spout 12 via an adhesive.

The tube end cap 4 has a structure in which an outer tube 41 and an inner tube 42 are joined to a bottom plate 40. The bottom plate 40 is in close contact with the tube end surface, the outer tube 41 covers the outer peripheral surface of the spout 12, and the inner tube A tube 42 is joined to the inner peripheral surface of the tube end.

An inner tube 2 having a socket 21 at one end is inserted into the outer tube 1, and the outer tube 1 and the inner tube 2 are tightly bonded with a foam adhesive 3 interposed therebetween.

The other end of the inner tube 2 is joined to the inner tube 42.

The gap between the outer tube 1 and the inner tube 2, that is, the thickness of the foamable adhesive 3, can be appropriately selected depending on the material of the outer tube 1, its inner diameter, etc., but is generally within the range of 0.5 to 5+ nm. The inner cylinder 42 of the tube end cap 4 may be formed in accordance with this gap.

Next, the manufacturing process of this composite pipe will be explained based on the longitudinal sectional view shown in FIG. 2.

First, an outer tube 1 is prepared which has an enlarged-diameter socket 11 at one end and a spigot 12 whose diameter is reduced with a step on the outer periphery of the other end. mate.

On the other hand, the inner tube 2 lining the outer tube 1 has an outer diameter slightly smaller than the inner diameter of the outer tube 1 and has a length approximately equal to that of the outer tube 1, and one end of the inner tube 2 is used. is enlarged to form a socket 21 with an outer diameter slightly smaller than the inner diameter of the expanded diameter socket 11.
to form. The socket 21 may be formed by any conventionally known means.

Next, the inner tube 2 is inserted into the outer tube 1, the other end of the inner tube 2 is joined to the inner tube 42, and one socket 21 is fixed to the outer tube 1 using the fixture 5. do.

At this time, it is important to fix the outer tube 1 and the inner tube 2 so that the gap between them is uniform in the circumferential direction.
is inserted into the socket 21, and the inner insertion tool 52 is inserted into the half annular body 51.
Fix it to the enlarged diameter socket 11 using.

Thereafter, the gap between the outer tube 1 and the inner tube 2 is filled with foamable adhesive 3.

Although this filling operation is not particularly limited, through holes 13 and 14 are bored at appropriate intervals in the tube wall of the outer tube 1, and the through holes 13 and 14 are
It is preferable to inject the foamable adhesive 3 through the hole 14 and exhaust the air through the through hole 14 to fill the gap between the outer tube 1 and the inner tube 2 with the adhesive 3.

As the foamable adhesive used in the present invention, a two-component adhesive in which a polyester resin and an isocyanate resin are bonded to each other to form a polyurethane resin is suitable,
This adhesive is foamed at room temperature to fill the gap between the outer tube 1 and the inner tube 2.

In this way, the inner peripheral surface of the outer tube 1 is covered with the inner tube 2 via the foaming adhesive 3, and the tube end of the spout 12 is covered with the tube end cap 4.
A composite tube coated with is obtained.

In the manufacturing method described above, the process of fitting the tube end cap 4 to the end of the spout 12 of the outer tube 1 and then inserting the inner tube 2 into the outer tube 1 was described. The tube is not limited to this manufacturing method; as shown in FIG. 3, after the inner tube 2 is pushed through the outer tube 1, the tube end cap 4 is fitted to the end of the tube to form the outer tube. A foamable adhesive 3 may be filled between the inner tube 1 and the inner tube 2.

In this case, a composite pipe having a spout as shown in the figure is obtained.

The composite tube thus obtained is one in which the spigot of the other tube is inserted into the enlarged diameter socket of one tube, and the two tubes are successively joined via an adhesive.

(Operations and Effects of the Invention) As described above, the method for manufacturing a composite tube of the present invention includes preparing an outer tube and an inner tube that matches the inner surface shape of the outer tube, and inserting an inner tube into the outer tube. After that, the gap between the outer tube and the inner tube is simply filled with foaming adhesive, so if the diameter of the inner tube is made accurate in advance, the inner diameter of the tube, especially the compound with the exact socket size, can be adjusted. A tube is obtained.

In addition, manufacturing this composite tube requires no special equipment other than an injection machine to fill the foam adhesive and a fixture to fix the inner tube to the outer tube. Therefore, it can be manufactured extremely easily and quickly, and the product cost can be significantly reduced.

The thus obtained composite tube has a foaming adhesive between the outer tube and the inner tube, so even when this composite tube is used as a transportation piping for a hot fluid, the heat in the radial direction of the inner tube is The expansion is absorbed by the foam adhesive so that the outer tube or inner tube will not be damaged.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a composite pipe showing one embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view showing the manufacturing process of the composite pipe, and Fig. 3 is a longitudinal cross-sectional view of a composite pipe showing another embodiment of the present invention. Main part. The cross-sectional views, FIGS. 4 and 5, are vertical cross-sectional views showing the manufacturing process of a conventional composite pipe. 1... Outer pipe 11... Expanded diameter socket 12
...... Socket 2 ... Synthetic resin inner tube 21 ... Socket 3 ... Foaming adhesive 4 ... Tube end cap 40...Bottom plate 41...Outer cylinder 42...Inner cylinder 5...
・・・Fixing tool'g twice

Claims (1)

[Scope of Claims] 1. An outer tube having an enlarged diameter socket at one end and a spigot at the other end has an outer diameter slightly smaller than the inner diameter of the outer tube, and the expanded diameter socket at one end thereof. A synthetic resin inner tube having a socket with an outer diameter slightly smaller than the inner diameter of the tube is inserted, and a foaming adhesive is interposed between the outer tube and the inner tube. Composite tube 2 characterized in that a tube end cap consisting of a tube is fitted, the outer tube covers the outer peripheral surface of the spout, and the inner tube is overlapped with the other end of the inner tube. an outer tube having a socket and a spigot at the other end; an outer tube having an outer diameter slightly smaller than the inner diameter of the outer tube; and a socket at one end having an outer diameter slightly smaller than the inner diameter of the enlarged diameter socket. A synthetic resin inner tube is prepared, and a tube end cap consisting of an outer tube and an inner tube is fitted to the spigot end of the outer tube, and the inner tube is inserted into the outer tube and the other end of the inner tube is inserted. and the inner cylinder,
A method for manufacturing a composite tube, characterized in that a foaming adhesive is then filled between the outer tube and the inner tube.