JPH06344443A - Manufacturing method of synthetic resin lining tube with inner spiral rib - Google Patents

Abstract

(57) [Abstract] [Purpose] Synthetic resin lining pipe with internal spiral ribs that does not give residual strain to the synthetic resin pipe that is the inner pipe during manufacturing and does not create a gap between the outer pipe and the inner pipe. It is intended to provide a manufacturing method of. [Structure] To obtain a synthetic resin lining pipe with an inner surface spiral rib, which comprises a synthetic resin inner pipe having multiple spiral ribs provided on the inner surface and a metal outer pipe surrounding the inner pipe, the inner pipe is used. After the adhesive is applied to at least one of the outer peripheral surface of the synthetic resin tube and the inner peripheral surface of the metal tube to be the outer tube, the outer diameter of the inner tube is the synthetic resin tube with the synthetic resin tube inserted in the metal tube. The diameter was reduced from the metal pipe side by using a diameter reducing device so that the diameter reduction ratio was 4% or less with respect to the outer diameter of the pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a synthetic resin lining pipe with an inner spiral rib.

[0002]

2. Description of the Related Art When a large amount of waste water flows down, the upper part of the pipe temporarily becomes negative pressure and the trap water is broken.
In order to solve problems such as drainage noise and air bubbles rolling up, and odors flowing into the room through the drainage pipe, a multi-row spiral rib is provided on the inner surface of the pipe, and drainage is always used as a swirling flow. There is an inner spiral rib tube that is designed to flow down while forming an air core in the center.

As the inner spiral rib tube, a synthetic resin inner tube having spiral ribs formed on the inner surface is lined from the outside with a metal outer tube in consideration of various problems such as fire resistance, corrosion resistance, and dew condensation. A synthetic resin lining pipe with an inner spiral rib (hereinafter, simply referred to as "lining pipe") is preferably used. Therefore, the applicant has applied an adhesive to at least one of the inner peripheral surface of the metal tube to be the outer tube and the outer peripheral surface of the synthetic resin tube to be the inner tube, and then insert the synthetic resin tube into the metal tube, Further, a method for manufacturing a lining pipe in which the diameter of the synthetic resin pipe is expanded by heating and pressurizing (or depressurizing) expansion so that the metal pipe and the expanded synthetic resin pipe as the inner pipe are brought into close contact with each other (JP-A-3-193431) (See Japanese Patent Publication) has already been proposed.

[0004]

However, the method of manufacturing the lining pipe described above has the following problems. That is, since the lining pipe obtained by the above method utilizes the heat pressurization (or depressurization) expansion when expanding the diameter of the synthetic resin pipe, the residual stress due to molding is large. Therefore, when this lining pipe is used as a drainage pipe, hot water flows down in the drainage pipe, so that the residual stress is released due to the temperature rise of the pipe body, that is, the inner pipe becomes smaller in diameter. The adhesive acting to bond the outer tube and the inner tube tends to peel off. In particular, when cold / hot water repeatedly flows down, a thermal expansion / contraction force is applied, and the inner tube is likely to contract.

Further, in the above manufacturing method, in order to facilitate the expansion, the synthetic resin pipe having a large thickness is used for the thick portion provided with the rib and the thin portion having no rib.
When heated and expanded from the inside of a synthetic resin pipe, the expandability differs between the thick part and the thin part, and the inner surface of the pipe tends to be distorted, and the thin part easily expands and follows the inner surface of the metal pipe, There is also a problem that the thick portion is less likely to expand and is likely to be molded with a part of air included in the metal tube.

In view of such circumstances, the present invention provides a lining pipe which does not give residual strain to a synthetic resin pipe which is an inner pipe at the time of manufacturing and does not generate a gap between the outer pipe and the inner pipe. It is intended to provide a manufacturing method of.

[0007]

In order to achieve such an object, the method of manufacturing a lining pipe according to the present invention comprises:
In obtaining a synthetic resin lining pipe with an internal spiral rib, which comprises a synthetic resin inner pipe provided with multiple helical ribs on the inner surface and a metal outer pipe surrounding the inner pipe, the synthetic resin pipe to be the inner pipe is obtained. After applying an adhesive to at least one of the outer peripheral surface of the metal pipe and the inner peripheral surface of the metal pipe to be the outer pipe, the outer diameter of the inner pipe is the outer diameter of the synthetic resin pipe when the synthetic resin pipe is inserted into the metal pipe. The diameter was reduced from the metal tube side by using a diameter reducing device so that the diameter reduction ratio was 4% or less with respect to the diameter.

In the above construction, the material of the synthetic resin pipe is not particularly limited, but examples thereof include vinyl chloride resin (PVC), polypropylene resin (PP), polyethylene resin (PE) and the like. The metal pipe is not particularly limited, but examples thereof include a steel pipe and a stainless steel pipe.

Various adhesives can be selected depending on the material of the synthetic resin pipe. For example, when the synthetic resin pipe is made of PVC, a chloroprene rubber adhesive, a urethane adhesive, an acrylic adhesive or the like is preferable. If the adhesive coating thickness is uniform, it is preferable that it be as thin as possible.
About 0.02 mm to 0.1 mm is suitable.

The diameter reducing device is not particularly limited,
For example, a roll reducing device generally used for reducing the diameter of steel pipes and a (tapping) reducing device using a rotary swaging machine can be cited. Note that heat treatment is preferably performed after the diameter reduction. The heating time and temperature are appropriately determined depending on the rigidity, melting point, etc. of the synthetic resin pipe and the adherence and temperature dependency of the adhesive itself, but when the synthetic resin pipe is made of PVC, the heating time and temperature are 10 to 60 ° C. It is preferably about 60 minutes.

The diameter reduction ratio is not particularly limited, but is 0.2%
It is particularly preferable to be about 3%, and if it is 0%, sufficient adhesion between the metal tube and the synthetic resin tube cannot be obtained, and if it exceeds 4%,
There is a concern that wrinkles may occur in the synthetic resin pipe that serves as the inner pipe and a gap may be formed between the synthetic resin pipe and the metal pipe.

[0012]

According to the above structure, the inner peripheral surface of the metal pipe is pressed against the outer peripheral surface of the synthetic resin pipe as the inner pipe by reducing the diameter of the metal pipe as the outer pipe by the diameter reducing device. Since the diameter of the pipe is slightly reduced, residual strain does not remain in the synthetic resin pipe serving as the inner pipe, and the outer pipe and the inner pipe are reliably integrated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. (Example 1) The following materials were prepared as materials to be used. Metal tube (steel tube for diameter reduction) outer diameter 120.0mm, inner diameter 114.
4mm, wall thickness 2.8mm Synthetic resin tube outer diameter 110.0mm, inner diameter excluding rib 105
mm, rib height 3 mm, rib pitch 750 mm, number of ribs 12 on the circumference (equal spacing) Adhesive chloroprene rubber adhesive diluted with solvent such as toluene Then, the following steps are shown in Fig. 1. Such a lining tube 1 was manufactured. In FIG. 1, 11 is an outer tube,
Reference numeral 12 is an inner tube, and 13 is a spiral rib.

The metal tube was washed with hydrochloric acid. An adhesive was applied to the inner surface of the metal tube and the outer surface of the synthetic resin tube. After air-drying the solvent of the adhesive, a synthetic resin tube was inserted into the inner surface of the metal tube. The outer surface of the metal pipe with the synthetic resin pipe inserted is reduced in diameter from the outside of the metal pipe 3 by using the roll reducing device 2 shown in FIG. 2, and then heat-treated at 80 ° C. for 60 minutes to obtain the lining pipe 1. It was

In the obtained lining pipe 1, the outer pipe 11 has an outer diameter of 114.3 mm, an inner diameter of 108.7 mm, and a wall thickness of 2.8 mm, and the inner pipe 12 has an outer diameter of 108.7 mm and an inner diameter of 103. 6 mm, the height of the rib 13 was 3 mm, and the pitch of the rib 13 was 770 mm. The outer diameter of the inner pipe 12 was 1.2% of the outer diameter of the synthetic resin pipe. (Embodiment 2) As shown in FIGS. 3 and 4, a lining pipe 1 as shown in FIG.
Got In FIG. 3, 41 is a feed roller and 42 is a take-up roller.

When the lining pipe 1 obtained in Example 1 and Example 2 was used as a drainage vertical pipe, the inner pipe 1
Even if a large amount of drainage flows in due to the spiral rib 13 provided on the inner surface of No. 2, an air core is always formed at the center of the pipe, and the trap is not broken at all. Further, since the synthetic resin pipe forming the inner pipe 12 has no residual strain, hot water,
Even when the cold water was repeatedly flowed through the drain pipe, the inner tube 12 had a small heat shrinkage, and the adhesion between the outer tube 11 and the inner tube 12 was not separated. In addition, in Examples 1 and 2, since the lining pipe 1 was heat-treated after the diameter reduction, the residual strain of the diameter-reduced synthetic resin pipe is further reduced, the adhesive force is improved, and the pipe end is also contracted. It was small.

[0017]

The method for manufacturing a synthetic resin lining pipe with an inner surface spiral rib according to the present invention is configured as described above, so that residual strain is not given to the synthetic resin pipe as the inner pipe during molding. Then, when the obtained lining pipe is used as a drain pipe after construction, in addition to the residual stress of the inner pipe being small, a direction in which hot water flows down and the tubular body temperature rises to release the residual stress, In other words, the synthetic resin pipe expands, becomes large in diameter, and works in a good direction of pressing the adhesive against the steel pipe, so that the adhesion between the outer pipe and the inner pipe does not peel off.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a lining pipe obtained by a method for manufacturing a lining pipe according to the present invention.

FIG. 2 is an explanatory view illustrating a state in which the diameter is reduced by using a roll diameter reducing device which is one embodiment of the method for manufacturing a lining pipe according to the present invention.

FIG. 3 is an explanatory view illustrating a state in which the diameter of the lining pipe is reduced by using a Tataki diameter reducing device using a rotary swaging machine, which is an embodiment of the method for manufacturing the lining pipe according to the present invention.

4 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

 1 Lining pipe 11 Outer pipe 12 Inner pipe 13 Spiral rib

Claims (1)

[Claims] 1. A synthetic resin lining pipe with an inner surface spiral rib, comprising: a synthetic resin inner tube having an inner surface provided with multiple helical ribs; and a metal outer tube surrounding the inner tube.
After applying an adhesive to at least one of the outer peripheral surface of the synthetic resin pipe to be the inner pipe and the inner peripheral surface of the metal pipe to be the outer pipe, in a state in which the synthetic resin pipe is inserted into the metal pipe, A synthetic resin lining pipe with an inner surface spiral rib, characterized in that the outer diameter is reduced from the metal pipe side by using a diameter reducing device so that the outer diameter of the synthetic resin pipe is 4% or less. Production method.