JPS62273828A - Manufacture of lining pipe - Google Patents

Abstract

PURPOSE:To enable the title lining pipe to stick close a synthetic resin pipe to an inner circumferential surface of an outer pipe by shortening a heating time of the synthetic resin pipe, by a method wherein the outer pipe composed of an inorganic material is heated at a temperature close to a softening temperature of the synthetic resin pipe, then a heat-expandable synthetic resin pipe pierced through the inside of the outer pipe is expanded by heating from the inner circumferential side. CONSTITUTION:An outer pipe 1 composed of an inorganic material is heated at the temperature of the softening temperature + or -10 deg.C of a synthetic resin pipe 2, then an adhesive agent is applied evenly to an inner circumferential surface of the pipe 1 or an outer circumferential surface of the pipe 2, and the pipe 2 is inserted into the pipe 1. Then a socket 21 of the pipe 2 is fitted in a socket 11 whose diameter has been expanded. Then those pipes 1, 2 are set up under a state where the other end part 22 of the pipe 2 is protruded through the other pipe end of the pipe 1, and stoppers 3, 4 are fitted respectively to the socket 21 and the other end part 22. Thus both ends of the synthetic resin pipe 2 have been sealed up, then a heating medium is introduced into the pipe 2 through the side of the stopper 3, and the pipe 2 is soften by discharging the heating medium through the stopper 4, so that the pipe 2 is expanded to adhere close to the inner circumferential surface of the outer pipe 1. Then stoppers 3 and 4 are removed, and the other end part 22 of the pipe 2 is soften by reheating, and turned reversely in the direction of the outside diameter to cover the outer circumferential surface of a spigot 12.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention (Field of Industrial Application) The present invention is directed to an outer tube made of an inorganic material such as concrete or asbestos having an expanded diameter socket at one end. vinyl chloride resin,
The present invention relates to a method of manufacturing a lining pipe by covering it with a synthetic resin pipe such as polyethylene resin.

(Prior art and its problems) In recent years, in underground pipes or sewage pipes for high-rise residential buildings, the inner circumferential surface of the outer pipe made of inorganic material such as concrete or asbestos is covered with synthetic resin pipes such as vinyl chloride resin. Lined pipes are used.

Conventionally, this lining tube has been made by inserting a thermally expandable synthetic resin tube into the outer tube, and then introducing a heating medium into the synthetic resin tube to soften the synthetic resin tube and expand it in the longitudinal direction. It was manufactured by increasing the internal pressure of the tube and bringing it into close contact with the inner peripheral surface of the outer tube.

However, heating a synthetic resin pipe only from the inner circumference takes time to heat the synthetic resin pipe to a predetermined softening temperature, and the entire pipe wall does not have a uniform temperature, resulting in uneven thickness due to uneven heating. However, there was a problem in that there were some areas where the adhesive did not stick properly. Moreover, if the outer tube is at room temperature,
As soon as the heated and expanded synthetic resin tube comes into contact with the inner circumferential surface of the outer tube, it is cooled and stops expanding, or its outer diameter shrinks, making it difficult to make close contact with the inner circumferential surface of the outer tube.

On the other hand, the outer pipe is made of inorganic materials such as concrete and asbestos.
Since the synthetic resin tube has relatively poor pressure resistance, when pressure is applied inside the synthetic resin tube to expand its diameter, this expansion pressure also acts on the inner circumferential surface of the outer tube, which may cause cracks in the outer tube. In particular, in the case of outer pipes made of inorganic materials such as asbestos, the inner diameter of the expanded diameter socket is considerably larger than that of the straight pipe part, so the synthetic resin pipe is attached to the inner circumferential surface of the expanded diameter socket. Applying sufficient internal pressure to achieve close contact not only caused cracks but also caused damage.

(Means for Solving the Problems) The present invention provides a method for covering the inner circumferential surface of an outer tube 1 made of an inorganic material such as concrete and having an enlarged diameter socket 11 at one end with a synthetic resin tube 2. A heat-expandable synthetic resin tube that is slightly longer than 1 and has an outer diameter slightly smaller than its inner diameter is prepared, and a socket 21 having an outer diameter that can fit into the expanded diameter socket 11 is formed at one end thereof. . On the other hand, the outer tube 1 is heated to a temperature close to the softening temperature of the synthetic resin tube 2, the synthetic resin tube 2 is inserted into the outer tube 1, and the socket 21 is inserted into the enlarged diameter socket 11 of the outer tube 1. At the same time, the other ends 22 of the synthetic resin tubes 2 are set to protrude from the other ends of the outer tubes 1. Therefore, a closure device 3.4 is attached to the socket 21 and the other end 22 of the synthetic resin pipe 2, respectively, to seal and close the synthetic resin pipe 2, and a heating medium is introduced into the heat-expandable synthetic resin pipe 2 to close the synthetic resin pipe 2. It is characterized by being expanded in the radial direction and brought into close contact with the inner circumferential surface of the outer tube 1.

EMBODIMENT OF THE INVENTION Hereinafter, the concrete structure of this invention is demonstrated in detail based on an Example with drawing.

(Example) FIG. 1 is a longitudinal sectional view of the manufacturing process showing an example of the present invention.
Figure 2 is a vertical cross-sectional view showing the synthetic resin tube in close contact with the inner peripheral surface of the outer tube, and Figure 3 is a longitudinal cross-sectional view showing the synthetic resin tube with the other end inverted to cover the outer peripheral surface of the outer tube's entrance. This is a cross-sectional view of main parts showing the state, and reference numeral 1 in the figure is an outer tube made of an inorganic material such as cement or asbestos, and 2 is a synthetic resin tube made of vinyl chloride resin, polyethylene resin, or the like.

The outer tube 1 has an enlarged-diameter socket 11 at one end of a straight tube having a predetermined length, and a socket 12 having a reduced outer diameter with a step at the other end.

On the other hand, the synthetic resin pipe 2 covering the inner peripheral surface of the outer pipe 1 is
A heat-expandable synthetic resin tube that is slightly longer than the outer tube 1 and has an outer diameter slightly smaller than its inner diameter is used, and one end of the synthetic resin tube 2 is fitted in advance into the expanded diameter socket 11. A socket 21 having an outer diameter that can be adjusted is formed in advance.

In the present invention, before inserting the synthetic resin tube 2 into the outer tube 1 and heating and expanding the synthetic resin tube 2, the outer tube 1 is first heated to a temperature close to the softening temperature of the synthetic resin tube 2.

In this heating step, it is preferable to immerse the outer tube 1 in an electric heating furnace or a bath of heated oil for a predetermined period of time, and heat the outer tube 1 to a temperature within ±10'C of the softening temperature of the synthetic resin tube 2. . This heating temperature is 10° higher than the softening temperature of the synthetic resin pipe 2.
℃ or more, the synthetic resin tube 2 contacts the inner peripheral surface of the outer tube 1 during the expansion process of the synthetic resin tube 2, which will be described later, and is simultaneously cooled and stops expanding, or the synthetic resin tube 2 contracts. Therefore, there may be an inconvenience that the inner circumferential surface of the outer tube 1 does not come into close contact with the outer tube 1.

After heating the outer tube 1 to a predetermined temperature, adhesive is uniformly applied to the inner circumferential surface of the extracurricular v11 or the outer circumferential surface of the synthetic resin tube 2,
A synthetic resin pipe 2 is inserted into the outer pipe 1.

Then, the socket 21 is fitted into the expanded diameter socket 11 of the outer tube 1, and the other end 22 of the synthetic resin tube 2 is set to protrude from the other end of the outer tube 1. As shown in FIG. 1, the obturator 3 is inserted into the socket 21 of the synthetic resin pipe 2, and
A closed MR 4 is attached to the other end 22.

After both ends of the synthetic resin pipe 2 are sealed and closed in this way, heated oil is injected into the synthetic resin pipe 2 from one of the obturators 3.
The synthetic resin pipe 2 is heated and softened by introducing a heating medium such as water vapor and discharging it from the other obturator 4. When the synthetic resin tube 2 softens, its diameter expands due to its self-expanding property, and expands until it comes into close contact with the inner circumferential surface of the outer tube 1.

During this heating and expansion process, the synthetic resin tube 2 is also heated from the outer circumferential side by the radiant heat of the outer tube 1, so the entire tube wall has a uniform temperature, and since there is no temperature unevenness, the radial stretching is uniform. It is applied to the inner peripheral surface of the outer tube 1! 511. In addition, since the outer tube 1 is heated to a temperature almost equal to the softening temperature of the synthetic resin tube 2, even if the synthetic resin tube 2 contacts the inner peripheral surface of the outer tube 1, it will not be cooled. There is no possibility of poor adhesion due to stoppage of expansion, contraction, etc.

After the synthetic resin tube 2 is completely in contact with the inner peripheral surface of the outer tube 1, the obturator 3.4 is inserted from both ends of the synthetic resin tube 2 as shown in FIG.
is removed, and the other end 22 of the synthetic resin tube 2 protruding from the opening 12 of the outer tube 1 is heated again to soften it. Therefore, as shown in FIG. 3, this tube end portion 22 is reversed in the outer diameter direction to cover the outer circumferential surface of the opening 12 w1. In this inversion process,
It is preferable to use a tube end folding mold previously proposed by the applicant in Japanese Patent Application No. 58-212125.

(Operations and Effects of the Invention) As described above, the present invention provides a method for covering an outer tube made of an inorganic material such as concrete or asbestos with a heat-expandable synthetic resin tube having a diameter-expanding port at one end. is heated to a temperature close to the softening temperature of the synthetic resin tube, and then the heat-expandable synthetic resin tube inserted into the outer tube is heated and expanded from the inner circumferential side, which greatly reduces the heating time of the synthetic resin tube. Can be shortened. In addition, during this heating process, the synthetic resin tube is heated from both the outer and inner circumferences, and the entire tube wall has a nearly uniform concentration, so that the radial stretching is uniform and the synthetic resin tube is heated from both sides. (closely adheres to the inner peripheral surface of the outer tube).

In addition, a socket having an outer diameter that can fit into the expanded diameter socket of the outer tube is formed in advance at one end of the synthetic resin pipe, and this socket is fitted into the expanded diameter socket of the outer tube. As a result, the inner diameter of the synthetic resin tube covering the inner circumferential surface of the enlarged-diameter socket of the outer tube is always constant, and a socket with extremely high dimensional accuracy can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a manufacturing process showing an embodiment of the present invention;
Figure 2 is a longitudinal cross-sectional view showing the inner peripheral surface of the outer tube covered with a synthetic resin pipe, and Figure 3 is a cross-sectional view of essential parts showing the outer peripheral surface of the outer tube inlet covered with a synthetic resin pipe. be. 1... Outer pipe 11... Expanded diameter socket 12
...Inlet 2...Synthetic resin pipe 21.
...Socket 22...Other end 3.4...
... Obturator v1 same

Claims (1)

[Claims] When covering the inner circumferential surface of an outer tube (1) made of inorganic material such as concrete with an enlarged diameter socket (11) at one end with a synthetic resin tube (2), it is necessary to A heat-expandable synthetic resin pipe with an outer diameter slightly smaller than its inner diameter (
2) is prepared, and a socket (21) having an outer diameter that can fit into the enlarged diameter socket (11) is formed at one end thereof, and the outer pipe (1) is replaced with a synthetic resin pipe (2). The synthetic resin pipe (2) is inserted into the outer pipe (1) and the socket (21) is inserted into the enlarged diameter socket (11) of the outer pipe (1). At the same time, the other end (22) of the synthetic resin pipe (2) is set to protrude from the other end of the outer pipe (1), and the socket (21) of the synthetic resin pipe (2) is fitted. and the other end (22)
After the obturators (3) and (4) are attached to the tubes and the tubes are sealed, a heating medium is introduced into the thermoplastic synthetic resin pipe (2) to expand the synthetic resin pipe (2) in the radial direction. Outer tube (1)
A method for manufacturing a lining pipe, characterized in that the lining pipe is brought into close contact with the inner circumferential surface of the pipe.