JPH028189B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synthetic resin pipe having a through hole in the pipe axis direction in the pipe wall.

In recent years, synthetic resin pipes that have thickened pipe walls to increase rigidity and have many through holes parallel to each other in the pipe axis direction to reduce weight are being used for piping in areas with high earth pressure. However, when connecting this pipe, as in the conventional method, a socket is formed at one end of the pipe into which the pipe socket is inserted, and the socket for the other pipe is inserted into this socket. In the method of piping by fitting, the through hole in the pipe axis direction of the pipe wall communicates with the outside of the pipe at the socket and the inside of the pipe at the insertion part, so the inside and outside of the pipe communicate through the through hole. There are disadvantages in that fluids such as sewage flowing inside the pipes flow out of the pipes, and fluids such as groundwater flow into the pipes from outside the pipes.

Therefore, in order to block this hole, a request was made in 1974.
As described in Publication No. 83024, it has been proposed to fit each protrusion of a ring with a large number of conical protrusions on the side surface into a through hole, but the shapes of the through holes vary; In particular, the through holes at the ends of the tubes in which the sockets are formed have large variations in shape due to deformation during molding of the sockets, and there is a drawback that the conical protrusion cannot be fitted into them. Also,
When a socket is formed by inserting a core mold that matches the inner shape of the socket into the heated tube end, irregularities corresponding to the through hole are created on the inner and outer surfaces of the socket, which improves the sealing between the socket and the socket. The appearance is poor, and furthermore, the strength and strength are deteriorated due to deformation.
In particular, it had the disadvantage of poor impact strength.

In addition, as a method of blocking the through hole,
Publication No. 52222 discloses that when forming a socket at the end of a tube, an expanding pin is inserted into a heated tube and pressed against the inner and outer walls of the tube to close it.
JP-A No. 55-73512 discloses that a plug material is inserted into the through hole to form an enlarged diameter socket, and the plug material and the pipe are tightly sealed to close the hole. Also, since an inner mold and an outer mold must be used to close the through hole and form the socket, there is a drawback that the device is complicated and expensive.

The present invention has been made to solve the above-mentioned drawbacks and to easily and reliably close the holes of synthetic resin pipes having holes in the pipe wall in the tube axis direction during socket molding. A socket into which a tube insertion port is inserted is formed at the end of the resin pipe which has a through hole in the pipe axial direction, and the socket covers almost the entire inner surface of the pipe wall and is folded back at the end surface of the pipe. The present invention relates to a synthetic resin pipe characterized in that a coating material covering almost the entire outer surface of the pipe wall is in close contact with the pipe wall surface either directly or through a sealing material.

Next, the synthetic resin pipe of the present invention will be explained with reference to the drawings.

FIG. 1 is a partially sectional front view of an example of the synthetic resin pipe of the present invention. Reference numeral 1 is a resin tube made of hard vinyl chloride resin or the like by extrusion molding or the like, and has a through hole 11 formed in the tube wall in the tube axis direction. A large number of through holes 11 are formed at approximately equal intervals in the circumferential direction of the tube 1. The cross-sectional shape of the resin tube 1 is not limited to a circular shape, but may be oval, elliptical, or square. Similarly, the cross-sectional shape of the through hole is not limited to a circular shape, and its size is determined as appropriate. A socket 2 into which a pipe socket is inserted is formed at the end of the resin pipe 1.

The illustrated socket 2 is for inserting a tube inlet of another pipe through an annular rubber packing, and an annular groove 21 into which the annular rubber packing is fitted is formed on the inner surface of the socket 2. The socket 2 may be one in which a tube insertion port is fitted and joined with an adhesive, or the annular groove 21 may be formed in two stages, deep and shallow.

A covering material 3 that covers almost the entire inner surface of the tube wall and is folded back at the end surface of the tube to cover almost the entire outer surface of the tube wall is attached to the socket 2 in close contact with the tube wall surface either directly or through a sealing material. ing. The covering material 3 may cover almost the entire inner surface of the tube wall of the socket 2, be folded back at the tube end surface, and cover almost the entire outer surface of the tube wall. Since it is covered to the depths deeper than the annular packing fitted to the pipe 21, it has excellent watertightness, and in the case of a socket to be joined with an adhesive, it is preferable that the pipe insertion port be covered to the position where it is tightly fitted. In addition, the covering material 3 is provided on the outer surface of the socket 2 to the depths beyond the part that bulges out corresponding to the annular groove 21, and furthermore, it is provided so as to cover almost the entire outer surface of the socket, so that it improves the appearance and impact strength. It will be excellent.

This covering material 3 is brought into close contact with the tube wall surface of the socket 2 either directly or through a sealing material, and the through hole 11 is sealed.

In order for the covering material 3 to be in close contact with the pipe wall surface of the socket 2, it is made of a heat-deformable synthetic resin that covers almost the entire inner and outer surfaces of the end of the resin pipe 1 and is connected at the end of the pipe. A double cylindrical body 31 as shown in FIG.
is placed over the end of the resin tube 1 having the through hole 11,
The socket 2 may be formed by heating and softening the material as it is and inserting a core mold therein. At this time, the double cylindrical body 31
It is preferable that the outer cylinder 32 and the inner cylinder 33 have as little space as possible between the outer surface and the inner surface of the resin tube 1, respectively. In addition, when the double cylindrical body 31 is heated and softened, the outer cylinder 32 contracts to a smaller diameter and the inner cylinder 33 expands to a larger diameter, so that when the socket 2 is formed, the pipe wall surface and It will be closely related to.

The double cylindrical body 31 can be made by injection molding, but it is possible to extrude a resin pipe with a larger diameter than the inner cylinder 33 and mold it while reducing the diameter so that it has the same outer diameter as the inner cylinder 33. A cylindrical body 4 having a thermally expandable diameter is made by this method, and this cylindrical body is heated and pushed into a mold 5 as shown in FIG. 3 to be folded outward to form an inner cylinder. A double cylindrical body 31 that expands thermally and whose outer cylinder thermally contracts can be formed.

If the double cylindrical body 31 is thin, it will break when inserting the tube into the socket 2, and if it is too thick, cracks and wrinkles will occur at the folded part during heat processing.
Although it depends on the diameter of the resin tube 1, it is preferably about 1.5 mm to 10 mm.

Further, a sealing material may be present between the covering material 3 and the pipe wall surface of the socket 2 to fill the gap. This sealing material may be an adhesive layer such as a hot melt adhesive or a sealing material such as rubber packing. Alternatively, a foaming composition may be applied to form a foam layer by heating during molding of the socket 2 to fill the gap between the tube wall and the covering material 3. These sealants are inserted from the through hole 11 to the socket 2.
It is only necessary to set it in a position that can prevent fluid from leaking between the wall surface and the covering material 3, and it is necessary to set the socket 2 when placing the double cylindrical body 31 over the end of the resin pipe. It is better to form.

The synthetic resin pipe of the present invention has the above-mentioned configuration, and since almost the entire inner and outer surfaces of the socket are tightly covered with a continuous covering material, the through hole is closed and the fluid flowing inside the pipe through the through hole is prevented. This prevents water from leaking or flowing in from outside the pipe. Also,
The covering material makes the entire inner and outer surfaces of the socket smooth even when the socket is formed, which improves the appearance, and also creates an annular groove in which the rubber packing fits when connected to a pipe inlet via the annular rubber packing. This prevents leakage between the rubber packing and the rubber packing. Furthermore,
There is no need to cover the hole with covering material to prevent leakage from the inside and outside walls of the socket, and to form the socket, it is only necessary to insert a core mold and expand the diameter of the resin pipe. The deformation of the pipe wall at the socket is small, and the outer surface of the socket is closely covered with the covering material, resulting in high strength, particularly impact strength.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway front view showing an embodiment of the present invention in cross section, Fig. 2 is a front view partially showing an example of a covering material in cross section, and Fig. 3 is an example of a method for forming the covering material. FIG. 1: Resin pipe, 11: Through hole, 2: Socket, 21: Annular groove, 3: Covering material.

Claims (1)

[Scope of Claims] 1. A socket into which a tube insertion port is inserted is formed at the end of a resin pipe that has a through hole in the pipe axis direction in the pipe wall, and the socket has a socket that extends approximately from the inner surface of the pipe wall. 1. A synthetic resin pipe characterized in that a coating material that covers the entire surface and is folded back at the end face of the pipe to cover almost the entire outer surface of the pipe wall is in close contact with the pipe wall surface either directly or through a sealing material. 2. The synthetic resin pipe according to claim 1, wherein the covering material covers the entire inner and outer surfaces of the pipe wall of the socket.