JPH0752247A - Lining technique for inner face of pipe now in use - Google Patents

Abstract

PURPOSE:To obtain a lining technique in which an inner face of a pipe now in use is lined with a resin pipe without the shrinkage of the resin pipe after cooling and a loss of a section. CONSTITUTION:In this technique, a lining resin pipe 1 made of a thermoplastic resin is inserted into a pipe line of a pipe 4 now in use; both ends 1a, 1b of the resin pipe are sealed with tapered inner pipes 9a, 9b; an internal pressure is applied by injecting a heating fluid from a pipe 13; and while this state is maintained, a heating means, i.e., either an infrared radiation generator or a dielectric heater, is swept from the end 1a of the lining resin pipe to the other end 1b thereof to successively expand the diameter of the lining resin pipe from the end 1a to the other end 1b so as to bring the lining resin pipe 1 into close contact with an inner face of the pipe 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lining method for an inner surface of an existing pipe.

[0002]

2. Description of the Related Art For example, a conventional method for lining a pipeline of an existing pipe buried in the ground with a resin pipe is as follows.
Many construction methods have been proposed. In all of these construction methods, insert a resin pipe for lining made of a thermoplastic resin having a diameter smaller than that of the existing pipe into the pipeline of the existing pipe, and then heat the resin pipe for the lining. The common work is to soften the inner pipe by applying internal pressure to expand the diameter, and thus to bring the resin pipe for lining into close contact with the inner surface of the existing pipe.

In this case, as a typical example of the softening / expanding of the lining resin pipe, the lining resin pipe is arranged in the pipeline of the existing pipe as described in, for example, JP-A-1-253425. Then, a method is known in which both ends of the resin pipe are sealed, and then steam having a predetermined temperature (predetermined pressure) is press-fitted into the resin pipe. In this method, the resin pipe is heated and softened by the steam that is press-fitted,
At the same time, the steam pressure will expand the diameter.

However, in the above-mentioned prior art, for example, when the existing pipe has a curved pipe portion such as an elbow pipe, a gap is partially formed between the expanded resin pipe and the inner surface of the existing pipe. Occurs, causing a problem that the cross-section loss increases. This is because the steam that is press-fitted when softening and expanding the diameter of the resin pipe preferentially softens and expands at both ends of the resin pipe, that is, both ends of the existing pipe, and adheres to the inner surface of the existing pipe. Therefore, the air existing between the resin pipe and the inner surface of the existing pipe is sealed at other portions in the longitudinal direction of the existing pipe, particularly at the central portion in the longitudinal direction.

Further, in the above-mentioned prior art, when the existing pipe has, for example, a recess of the joint portion or a joint step, when the resin pipe is expanded over its entire length, parts are formed at those portions. Due to the mechanical restraint, there is a case where the diameter is completely expanded and it is not possible to make close contact with the inner surface of the existing pipe. Furthermore,
Since the resin pipe expands from a small diameter state, internal residual stress is latent in the longitudinal direction during the process of expanding the diameter. Therefore, when the resin pipe after the diameter expansion is allowed to cool and its shape is fixed, the residual stress is instantaneously released. That is, the resin pipe after the diameter expansion starts to shrink mainly in the longitudinal direction, and as a result, the situation where the resin pipe separates from the inner surface of the existing pipe begins to occur.

In order to solve the above-mentioned problems in the construction method disclosed in JP-A-1-253425, the following construction method is proposed in JP-A-3-175018. In this method, after softening and expanding the diameter of the resin pipe and once lining it on the inner surface of the existing pipe, a slip stopper that slides into contact with the inner surface of the resin pipe while press-fitting steam into the resin pipe is inserted from one end of the resin pipe. By running to the other end, the lined resin pipe is reheated, and the internal residual stress of the expanded resin pipe is released from the other end.

[0007] With this method, it is possible to greatly reduce the shrinkage of the resin pipe in the longitudinal direction after cooling. But,
After lining the resin pipe once and reheating it,
The number of processes has increased, and it is hard to say that it is appropriate as an actual construction method. Further, in Japanese Patent Laid-Open No. 63-285395, a resin pipe having a flattened cross-section is inserted into a pipe line of an existing pipe, and then both ends of the resin pipe are sealed and steam is press-fitted into the resin pipe. There is disclosed a method of gradually softening and expanding the diameter of the resin pipe in the longitudinal direction by passing a heating pig having a predetermined diameter from one end to the other end inside the resin.

In this method, heating and softening of the resin pipe proceeds by heat conduction with the heating pig or convection of the press-fitting steam. However, the inserted resin tube is usually a heat-defective conductor, and a low temperature layer is formed on the surface thereof. Therefore, when softening and expanding the diameter of this heat-defective conductor, the resin pipe is a heat-defective conductor. There is no choice but to set the steam temperature to be high.

This means that the thermal efficiency during the lining work becomes poor, the time required for the lining work becomes long, and the pressure of the steam to be press-fitted becomes high. It is hard to say that it is appropriate as a construction method.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems in the conventional lining method, to enable the lining work to be advanced with high thermal efficiency, and for the existing pipe to have a curved pipe portion. Also provides a lining method for the inner surface of the existing pipe, which can be lined without creating a gap between the inner surface of the existing pipe and the resin pipe, and which can proceed with the lining work while releasing the internal residual stress in the longitudinal direction. It is to be.

[0011]

In order to achieve the above-mentioned object, in the present invention, a resin pipe for lining made of a thermoplastic resin is inserted into the pipeline of an existing pipe, and both ends of the resin pipe for lining are inserted. Is sealed and internal pressure is applied by a heating fluid, and while maintaining this state, the heating means of either the infrared ray generator or the dielectric heating device is driven from one end to the other end in the resin pipe for lining, and the lining for There is provided a lining method for an inner surface of an existing pipe, wherein the diameter of the resin pipe is gradually increased from one end to the other end and the inner surface of the existing pipe is closely contacted with the resin pipe.

In the method of the present invention, a dielectric heating device or an infrared generator is used as the heating means in order to increase the thermal efficiency when the resin pipe is softened and expanded. When the dielectric heating device is activated, the constituent atoms of the resin tube located on the outer circumference are polarized and rub against each other to generate heat, and when the infrared generator is activated, the generated infrared rays are generated. Energy is converted into molecular vibration energy of the resin forming the resin tube, and as a result, the resin tube self-heats. The heating by these devices is not heat transfer heating in which a heat medium is interposed unlike in the case of steam heating, but the resin pipe can directly generate heat to raise the temperature to a desired temperature, so that its thermal efficiency is extremely high. The rapid heating of the resin tube can be achieved.

[0013]

In the construction method of the present invention, the resin pipe inserted into the pipeline of the existing pipe has a sealed structure at both ends thereof, and is constantly radiated in the radial direction by a heating fluid such as hot air or steam injected into the inside. Is receiving the force to expand the diameter. Then, at one end of the resin pipe, a heating means having a diameter smaller than the inner diameter of the resin pipe and having extremely high thermal efficiency is arranged. While operating the heating means, the heating means is driven to the other end of the resin pipe.

In this process, the resin pipe is gradually softened by sequentially self-heating from one end to the other end, and at the same time, the softened portion is gradually expanded in diameter by the action of the internal pressure of the heating fluid described above. It adheres to the inner surface of the tube. Therefore, the air present between the resin pipe and the inner surface of the existing pipe will be expelled from one end of the expanding resin pipe toward the other end, and the inner surface of the resin pipe and the existing pipe will be expelled. No void is generated between the and. That is, the cross-section loss is greatly reduced.

Further, the internal residual stress generated in the process of expanding the diameter is also gradually released from one end of the resin pipe to the other end, so that shrinkage in the longitudinal direction of the resin pipe after cooling is reduced. Furthermore, by controlling the output energy of the heating means to be used according to the type of the resin tube to be inserted, that is, the softening point and the melting point of the constituent resin, the heating means can be swept once. The resin pipe can be lined on the inner surface of the existing pipe while suppressing the contraction in the longitudinal direction.

[0016]

Examples of the invention

Example 1 First, a resin pipe for lining made of a thermoplastic resin is inserted into a pipeline of an existing pipe. The thermoplastic resin that is the material of the resin pipe is not particularly limited, but for example, a low melting point amorphous resin such as polyvinyl chloride, or a crystalline resin such as polyethylene, polypropylene or nylon is used. You can

The resin pipe may be inserted into the pipeline of the existing pipe in the same manner as the conventional construction method. For example, as shown in FIG. 1, the resin pipe 1 is carried into the construction site, the tip of the resin pipe 1 is fixed to the pull-in rope 2, and the pull-in rope 2 is wound up by the winding winch 3, whereby the resin pipe 1 is already installed. Insert into the conduit of tube 4. Further, as shown in FIG. 2, for example, the resin pipe 1 having a flattened cross section and wound around a drum 5 is carried into a construction site, and its tip is fixed to a pull-in rope 2 which is wound up by a winding winch 3. Then, the drum is housed in a container 6 having a closed structure, and warm air or steam is introduced from the heat medium generator 7 into the container 6 and a pipe 6a extending from the container 6 to near one end of the existing pipe 4. By softening the resin pipe 1 and letting in the warm air or steam similarly generated by the heat medium generator 7 from the other end of the existing pipe 4, the winding rope 2 is wound by the winding winch 3. Alternatively, the softened resin pipe 1 may be inserted into the pipeline of the existing pipe 4.

After the resin pipe 1 is inserted over the entire length of the pipeline of the existing pipe 4, as shown in FIG. 3, the length of the resin pipe 1 is longer than that of the existing pipe 4. Both ends of the resin pipe 1 are cut. Then, as shown in FIG.
A dielectric heating device 8 to be described later is disposed as a heating means on the side of the one end 1a in the conduit of the resin pipe 1, and a tapered inner pipe 9a for sealing the one end is fitted into the opening of the one end 1a of the resin pipe 1.
A ring-shaped tapered outer tube 10a is fitted on the outer side of
This tapered inner pipe 9a is pressed by the jack 11 to spread the opening of the resin pipe 1 by the tapered surface, and the portion of the one end 1a of the resin pipe 1 is crimped to the inner surface of the one end 4a of the existing pipe 4, whereby At the same time as the one end 1a of the resin pipe 1 is sealed, the one end 4a of the existing pipe 4 is also sealed.

On the other hand, the taper inner tube 9b sealed at one end and the taper outer tube 10b having a ring shape are fitted into the other end 1b of the resin pipe 1, and the other end 1b is tapered by a jack as in the case of the one end 1a. Do not press the inner tube 9b. As a result, the other end 4b of the existing pipe 4 and the other end 1b of the resin pipe 1 are not crimped,
As shown as a partially enlarged view in FIG. 5, a clearance is formed between the other end 1b of the resin pipe 1 and the other end 4b of the existing pipe 4, and both are in a free state.

From the tapered inner tube 9b, the conductors 8a, 8b for operating the above-mentioned dielectric heating device 8 are pulled out airtightly and slidably with the tapered inner tube 9b and connected to the high frequency power source 12. . Further, a pipe 13 for press-fitting a pressure medium such as warm air or steam is connected to the tapered inner pipe 9b, and the flow rate (pressure) of the pressure medium can be adjusted by a valve 13a.

In this way, both ends 1a, 1 of the resin pipe 1 are
b has a sealed structure with the tapered inner pipes 9a and 9b. Therefore, by pressurizing the pressure medium from the pipe 13, the resin pipe 1 can always be applied with an inner pressure for expanding the diameter. In addition, one end 1a of the resin pipe 1 and the existing pipe 4
Since the one end 4a is pressure-bonded and the other end is free, the internal residual stress generated when the resin pipe 1 is softened / expanded can be released and removed from the other end 1b.

In this state, by pulling the conductive wires 8a and 8b while operating the dielectric heating device 8, the dielectric heating device 8 is swept in the conduit of the resin pipe 1 from one end 1a to the other end 1b. It Here, the dielectric heating device 8 will be described. 6 and 7 are schematic views of an induction heating device assembled with hollow conductors. In this device, one hollow conductor wire 8c forms a plurality of circular spiral wire portions 8d as electrodes without contacting each other, and the distance between the circular spiral wire portions on the one end 1a side of the resin pipe 1 is It is narrower than the distance between the circular spiral portions on the side of the other end 1b of the resin pipe 1 at a constant ratio. Here, the hollow conducting wire 8c forming the circular spiral portion 8d
Is a forward hole of the cooling water that is circulated and supplied, and a hollow portion of the hollow conductor 8c that passes through the center of the circular spiral wire portion 8d is a return hole of the cooling water. It is connected. Further, the outer diameter of the circular spiral portion 8d is smaller than the inner diameter of the resin pipe 1 before the diameter expansion, and inside the circular spiral portion 8d, a flexible heat insulating material such as glass fiber is used. The material 8e is filled and shaped into a bulk body as a whole.

The dielectric heating device 8 has a circular spiral wire structure in which the entire skeleton is formed of one hollow conductive wire, so that it can be flexibly bent in the longitudinal direction. Therefore, even if the resin pipe is bent, it can also pass through the pipe line while bending itself. FIG. 8 is a schematic view showing an example of another dielectric heating device. In this device, a plurality of circular electrode rings 8f are machined with non-perforated conductors, and the circular electrode rings 8f are narrowed at the same ratio as the mutual spacing on the one end 1a side of the resin tube is smaller than the mutual spacing on the other end 1b side. The two non-perforated conducting wires 8a and 8b are alternately connected to the circular electrode rings 8f and the reinforcing wires 8g of the circular electrode rings without coming into contact with each other, and are electrically connected to two electrodes. It is structured. Then, if necessary, the inner space of these circular electrode rings 8f may be filled with a flexible heat insulating material such as glass fiber, and the whole may be shaped into a bulk body.

In these dielectric heating devices 8, when a predetermined high frequency voltage is applied from the high frequency power source 12, an electric field is generated between the circular electrodes. Then, in the resin tube 1 that is close to these circular electrodes, the atoms and electrons of the constituent resin are polarized in a length portion corresponding to the interval between these circular electrodes, and a frictional heating phenomenon occurs, so that the resin tube 1 Self-heating.

Therefore, when the dielectric heating device 8 is operated to run from one end 1a of the resin pipe 1 toward the other end 1b, the resin pipe 1 sequentially self-heats from its one end 1a.
It will soften. At the same time, since the internal pressure for expanding the diameter of the resin pipe 1 is applied to the resin pipe 1, the resin pipe 1 is gradually expanded in diameter from the softened portion.

That is, as shown in FIG. 7, the resin pipe 1
Gradually softens and expands in diameter from one end 1a to the other end 1b thereof and adheres to the inner surface of the existing pipe 4. And this softening
Since the internal residual stress generated in the resin pipe 1 in the process of expanding the diameter is released toward the other end of the resin pipe 1 which is a free end, it shrinks even in the cooling process after the completion of the entire expansion of the diameter. Things will not happen.

Furthermore, the air existing between the resin pipe 1 and the inner surface of the existing pipe 4 also becomes the other end 4b of the existing pipe 4 as the diameter expansion of the resin pipe 1 progresses in one direction. The resin pipe 1 will be smoothly expelled from the clearance with the other end 1b, and no void will be formed between them. In the process of softening and expanding the diameter of this resin pipe, the internal pressure applied to the resin pipe is
It is preferably 0.5 to ^2.5 kg / cm ² . Further, the temperature of the resin pipe is set to 90 ° C. or higher, though it depends on the constituent resin.

For example, in the case of a tube made of an amorphous resin such as polyvinyl chloride, it is sufficient to raise the temperature to about 90 to 130 ° C. Further, in the case of a tube made of a non-polar crystalline resin such as crosslinked medium density polyethylene, it is necessary to raise the temperature above its melting point, that is, above the recrystallization temperature. In the case of the crosslinked medium density polyethylene pipe described above, the temperature is raised to a temperature of 140 to 160 ° C.

When the resin pipe is a polyvinyl chloride pipe, since polyvinyl chloride is a polar and non-crystalline resin, a dipole moment is also generated when the dielectric heating device is operated, so that a low frequency is generated. Even with a power supply, the temperature can be raised to a desired temperature in a short time. That is, at this time, it is possible to use the dielectric heating device assembled with the non-perforated wire as shown in FIG.

For a resin tube made of a crystalline resin which has to be heated to a relatively high temperature, after inserting it into an existing tube, the whole is steamed at 90 to 125 ° C.
Preheating to a certain temperature is effective because the temperature can be raised to the required temperature in a short time. Resin tube 1
If the diameter is increased and the inner surface of the existing pipe 4 is closely contacted, then
The operation of the dielectric heating device 8 is stopped, the pressure medium is continuously injected from the pipe 13, the resin pipe 1 is allowed to cool while the internal pressure is maintained for a desired time, and the method of the present invention is completed.

When the existing pipe 4 is a pipe of a good electric conductor such as a welded steel pipe or a cast iron pipe, as shown in FIG. 9, the existing pipe 4 is used as one electrode and the circular electrode of the dielectric heating device is used. A high-frequency voltage may be applied so that the other electrode becomes the other electrode. Example 2 FIG. 10 is a schematic view showing a case where an infrared ray generator 14 is used as a heating means. In this case, instead of the dielectric heating device used in Example 1, an infrared ray generating device 14 described later is used.
The entire process is performed in the same procedure as in Example 1 except that the resin is swept from one end 1a to the other end 1b of the resin pipe 1.

As shown in the partially cutaway perspective view of FIG. 11, the infrared ray generator 14 has a cylindrical body 14a made of, for example, stainless steel, an infrared radiation layer 14b formed on the outer periphery thereof, and an inside of the cylindrical body. It is composed of a thin tube 14c which is spirally wound around and is arranged, and a heat insulating material 14d such as a glass fiber filled inside the cylindrical body. Examples of the infrared radiation layer 14b include a black oxide film formed by firing a stainless steel cylindrical body 14a in the atmosphere at a temperature of 1000 ° C. or higher, a black baking coating film containing ceramics such as cordierite or titanium. An example is a thermal spray coating of ceramics such as aluminum oxide. Each of these layers can emit heat rays from far infrared rays to infrared rays.

The thin tube 14c disposed in the cylindrical body 14a is made of, for example, stainless steel, and its center is made of nichrome as a heating radiation source.
A core wire 14e made of tungsten, platinum or the like is wired, and a thin tube 14c is filled with an inorganic powder 14f such as magnesia. One end and the other end of the core wire 14e of the thin tube 14c are connected to a flexible covered electric wire 15 via a mounting plug 14g, and the covered electric wire 15 is connected to a power source 16.

In the case of this infrared generator 14, a power source 16
When the coated electric wire 15 is energized from the core wire 14e, heat is generated,
Due to the heat energy, infrared rays or far infrared rays having a predetermined wavelength are radiated from the infrared radiating layer 14b and reach the inner surface of the resin pipe 1 located outside the device 14. Generally, an organic compound has an absorption spectrum at a natural frequency defined by its molecular structure, atomic weight, binding force and the like. For example, in the case of polyethylene resin, the natural frequency showing its absorption spectrum is about 3 μHz, 7 μH
z, 14 μHz, etc.

Therefore, when the wavelength of infrared rays or far infrared rays radiated from the infrared radiation layer 14b is synchronized with the natural frequency of the resin forming the resin tube, these light energies are absorbed by the resin forming the resin tube, This is converted into molecular vibrational energy, and as a result, the resin tube starts self-heating. In addition, this infrared generator 14
It is preferable to connect an appropriate number of them in series and run them inside the resin pipe because the thermal efficiency of the resin pipe can be increased.

[0036]

As is clear from the above description, according to the method of the present invention, softening of the resin pipe for lining by traversing a heating means having an extremely high thermal efficiency such as an infrared generator or a dielectric device. The diameter expansion and the adhesion to the inner surface of the existing pipe can be performed in one step. The softening / expanding of the resin pipe is continuously progressed from one end to the other end, and the other end is a free end. The resin pipe is released from the end and the shrinkage of the resin pipe after cooling is prevented. Also,
Air existing between the resin pipe and the inner surface of the existing pipe is also expelled sequentially from the free end of the existing pipe, so there is no gap between the resin pipe and the inner surface of the existing pipe, and cross-section loss is almost eliminated. can do.

Further, the operating conditions of the heating means can be controlled in accordance with the characteristics of the resin pipe used.

[Brief description of drawings]

FIG. 1 is a schematic view showing a state in which a resin pipe for lining is inserted into a pipeline of an existing pipe.

FIG. 2 is a schematic view showing another state in which a resin pipe for lining is inserted into a pipeline of an existing pipe.

FIG. 3 is a schematic view showing a state in which a resin pipe for lining is inserted into a pipeline of an existing pipe.

FIG. 4 is a schematic view showing a state in which the construction method of the present invention is carried out.

5 is a partially enlarged view showing the other end side of the resin pipe for lining in FIG.

FIG. 6 is a schematic view showing a part of an induction heating device.

FIG. 7 is a schematic view showing a dielectric heating device arranged in a resin pipe for lining.

FIG. 8 is a schematic view showing another dielectric heating device.

FIG. 9 is a schematic view showing an example of carrying out the method of the present invention on an existing pipe having a good electric conductor.

FIG. 10 is a schematic view showing a method of the present invention using an infrared generator.

FIG. 11 is a partially cutaway perspective view showing an infrared generator.

12 is a perspective view showing a thin tube in FIG.

[Explanation of symbols]

 1 Resin Pipe for Lining 1a One End of Resin Pipe 1 for Lining 1b Other End of Resin Pipe for Lining 2 Pulling Rope 3 Winding Winch 4 Existing Pipe 4a One End of Existing Pipe 4 4b Other End of Existing Pipe 4 Drum 6a Pipe 7 Heat medium generating device 8 Dielectric heating device (heating means) 8a, 8b Conducting wire 8c Hollow conducting wire 8d Circular spiral wire portion (circular electrode) 8e Heat insulating material 8f Circular coil (circular electrode) 8g Reinforcing wire 9a, 9b Tapered inner tube 10a, 10b Tapered outer tube 11 Jack 12 High frequency power supply 13 Piping 13a Valve 14 Infrared generator (heating means) 14a Cylinder 14b Infrared radiation layer 14c Capillary tube 14d Thermal insulation material 14f Core wire 14g Inorganic powder 15 Coated wire 16 Power supply

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuo Sadamitsu 2-6-1, Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Inventor Shintaro Ikeda 347-44 Unomori, Sagamihara City, Kanagawa Prefecture (72 ) Inventor Toru Fukusato 3-3-7 Fukamihigashi, Yamato City, Kanagawa Prefecture Bonur Fukami A

Claims (1)

[Claims] 1. A lining resin pipe made of a thermoplastic resin is inserted into a pipeline of an existing pipe, both ends of the lining resin pipe are sealed, and an internal pressure is applied by a heating fluid, while maintaining the state. The heating means of either the infrared ray generator or the dielectric heating device is traversed from one end to the other end in the resin pipe for lining, and the diameter of the resin pipe for lining is sequentially expanded from one end to the other end of the existing pipe. Inner surface lining method for existing pipes, which is closely attached to the inner surface.