JPH0752246A - Lining technique for inner face of pipe now in use - Google Patents

Abstract

PURPOSE:To obtain a lining technique in which when a lining resin pipe is made of a crystalline thermoplastic resin, an inner face of a pipe now in use is lined with the resin pipe with the inhibition of the shrinkage of the resin pipe. CONSTITUTION:In a lining technique for an inner face of a pipe in use, a lining resin pipe made of a crystalline thermoplastic resin is inserted into a pipe line of an installed pipe 4, thereafter being softened and expanded in diameter to be brought into close contact with the inner face of the pipe. In this technique, the both ends of the expanded-diameter resin pipe 1' are sealed with tapered inner pipes 8a, 8b, and an internal pressure us applied by a heating fluid. While this state is maintained, a heating means 14, i.e., either an infrared radiation generator or a dielectric heater, is swept from one end 1a of the expanded- diameter resin pipe 1' to the other end 1b thereof to successively heat the resin pipe 1' to at least the melting point of the resin forming the resin pipe from the end 1a of the expanded-diameter resin pipe 1' to the other end 1b thereof.

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. For example, JP-A-1-29
According to Japanese Patent No. 5828, a polyethylene pipe having a diameter smaller than that of the existing pipe is inserted into the pipeline of the existing pipe, and then both ends of the polyethylene pipe are made into a sealed structure so that steam at a predetermined temperature (predetermined pressure) is inside. A method has been proposed in which the polyethylene pipe is heated and softened by press-fitting, and at the same time, the polyethylene pipe is expanded in diameter and brought into close contact with the inner surface of the existing pipe.

In this construction method, the resin pipe for lining is made of an amorphous thermoplastic resin (for example, polyvinyl chloride) having a relatively low melting point.
If it is composed of etc., it is sufficiently applicable,
However, when the constituent resin of the resin tube is a crystalline thermoplastic resin having a relatively high melting point such as polyethylene or polypropylene, the following disadvantages occur. That is, the crystalline thermoplastic resin has a strong molecular orientation,
Since the volume ratio changes greatly with temperature, the original restoring force is strong,
It shows the behavior to restore the shape at the time of molding.

When steam is used as a heating / pressurizing medium in the lining method, the steam has a temperature of 110 ° C. and a pressure of about 1.5 kgf / cm ² (gauge pressure) and a temperature of 120.
It is customarily used at a pressure of about 2 kgf / cm ² at ℃. This is because the steam pressure becomes higher when used at higher temperatures, which is dangerous during construction. However, if the resin pipe is, for example, high density polyethylene (melting point is 1
(30 to 140 ° C), polyethylene is not heated above the melting point even if the resin pipe is softened and expanded by steam at the above temperature and pressure, so the expanded pipe is expanded. Due to the original shape restoring force generated, the cross-sectional area of the resin pipe that has once come into close contact with the inner surface of No. 3 gradually decreases and may peel off from 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 problems caused by the generation of internal residual stress, Japanese Patent Laid-Open No. 175018/1993 proposes the following method. 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 slidably contacts the inner surface of the resin pipe from one end of the resin pipe while press-fitting steam into the resin pipe, for example. Run to the other end. As a result, the lined resin pipe is reheated, and the internal residual stress of the resin pipe after the diameter expansion is released from the other end.

However, since steam is used to heat and pressurize the resin pipe in this method as well, when the resin pipe is made of polyethylene, for example, polyethylene is softened when the sliding plug is swept. Although the stress relaxation of the resin pipe can be achieved, the next time the resin pipe is cooled, the resin pipe will be fixed in a shape memory state corresponding to the steam temperature. That is, the original restoring force is still in operation.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems in the conventional lining method when a tube made of a crystalline thermoplastic resin such as a polyethylene tube or a polypropylene tube is used as the resin tube, An object of the present invention is to provide a lining construction method for the inner surface of an existing pipe, which is capable of preventing the shrinkage of the diameter-expanded resin pipe that has been expanded in diameter and once brought into close contact with the inner surface of the existing pipe.

[0009]

In order to achieve the above-mentioned object, in the present invention, a resin pipe for lining made of a crystalline thermoplastic resin is inserted into the pipeline of an existing pipe, and then the resin for lining is provided. In the lining method for the inner surface of the existing pipe that softens and expands the diameter of the pipe to adhere it to the inner surface of the existing pipe, both ends of the expanded resin pipe are sealed and internal pressure is applied by heating fluid to maintain that state. As it is, the heating means of either the infrared ray generator or the dielectric heating device is swept from one end to the other end of the diameter-expanded resin pipe, and the diameter-expansion resin pipe is applied from one end to the other end of the pipe to obtain the melting point of the constituent resin. There is provided a lining method for an inner surface of an existing pipe, which is characterized by sequentially heating to the above temperature.

In the method of the present invention, a dielectric heating device or an infrared ray generating device is used as the heating means in order to rapidly generate heat in the expanded resin tube and quickly fix the shape of the expanded resin tube. is necessary. 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 which involves a heat medium as in the case of steam heating, but the diameter-expanded resin pipe can directly cause self-heating, so its thermal efficiency is extremely high and Rapid heating can be achieved.

[0011]

In the construction method of the present invention, first, in the same manner as in the conventional construction method, the resin pipe is once softened / expanded and then adhered to the inner surface of the existing pipe. After that, both ends of the diameter-expanded resin pipe are made into a sealed structure, and the state in which a force for expanding the diameter of the diameter-expanding resin tube is constantly maintained by the heated fluid such as hot air or steam.

A heating means having a diameter smaller than the inner diameter of the resin tube is arranged at one end of the diameter-expanded resin tube, and the heating means is operated to run to the other end of the diameter-expanded resin tube. By using a dielectric heating device or an infrared generator as the heating means used at this time, the temperature of the expanded diameter resin tube can be efficiently set in a short time so as to be a temperature equal to or higher than the melting point of the resin.

Therefore, in the constituent resin of the diameter-expanded resin pipe, the internal residual stress generated during the diameter expansion is released, and above all, the original shape restoring force is lost. As a result, after cooling, recrystallization occurs and the shape at the applied temperature is memorized, and shrinkage in the radial direction and the longitudinal direction is suppressed. At the same time, the expanded resin tube melts once,
Under the action of internal pressure, it will adhere to the inner surface of the existing pipe,
The adhesion between the two becomes extremely excellent.

[0014]

Examples of the invention

Example 1 First, a resin pipe for lining made of a crystalline thermoplastic resin is inserted into a pipeline of an existing pipe. The crystalline thermoplastic resin that is the material of the resin pipe is not particularly limited, but polyethylene, polypropylene, or nylon can be used.

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 inserting the resin pipe 1 over the entire length of the pipe line 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.
The tapered inner pipes 8a and 8b, which are closed at one end, are fitted into the openings of the one end 1a and the other end 1b of the resin pipe 1, respectively.
Ring-shaped tapered outer pipes 9a, 9b are fitted respectively on the outer side of one end 1a and the outer side of the other end b, and these tapered inner pipes 8a, 8b are pressed by jacks 10a, 10b, respectively. As a result, the openings at both ends 1a, 1b of the resin pipe 1 are expanded in diameter by the tapered surfaces of the inner pipes 8a, 8b, and the openings are sealed by the tapered inner pipes 8a, 8b.

Here, for example, a pipe 11b having a valve 11d is connected to the taper inner pipe 8b, and this pipe 11b is further connected to a heat medium generator 12 for supplying hot air or steam into the pipe 11b. ing. Further, the other tapered inner pipe 8b is also provided with a valve 11c, and the pipe 1 having one end opened
1a is connected. Then, jacks 10a, 10
b to press the taper inner pipes 8a and 8b, respectively, so that the resin pipe 1
With both ends sealed, the valve 11c is closed and the valve 11d is opened to operate the heat medium generator 12, and for example, steam having a predetermined temperature and a predetermined pressure is press-fitted into the resin pipe 1 from the pipe 11b.

As a result, the resin pipe 1 is heated and softened,
The pressure is increased by steam and the diameter of the existing pipe 4 is closely contacted.
For example, if the resin pipe 1 is a polyethylene pipe with a diameter of 150 mm and a wall thickness of 8 mm (density 0.946 g / cm ³ ), and the pressure of the steam to be press-fitted is selected to be ² to 4 kg / cm ² (temperature 100 to 130 ° C.). It is possible to expand the diameter of the polyethylene pipe in a time of about 1 to 2 hours so that the polyethylene pipe can be closely attached to the inner surface of the existing pipe.

After the diameter of the resin pipe 1 is expanded and brought into close contact with the inner surface of the existing pipe 4, the valve 11c is then opened and the valve 11d is opened.
Is closed to return the pressure in the expanded resin tube to atmospheric pressure, the pressing operation of the jacks 10a, 10b on the tapered inner tubes 81a, 8b is also released, and the tapered inner tube and the tapered outer tube are removed to remove the expanded resin tube. Unseal the sealing structure. Then, as shown in FIG. 5, a dielectric heating device 14 described later is arranged at one end 1a of the conduit of the diameter-expanded resin pipe 1 ', and conductive wires 14a and 14b for operating the dielectric heating device 14 are tapered. After being pulled out airtightly and slidably with the pipe 8a and connected to the high-frequency power source 13, both ends 1a and 1b of the expanded resin pipe 1'are again made into a sealed structure by the above-mentioned method, the valve 11c is closed, and the valve 11d. Is opened and internal pressure is applied to the expanded resin tube 1 '.

In this state, by pulling the conductive wires 14a and 14b while operating the dielectric heating device 14, the dielectric heating device 14 is moved into the conduit of the expanded diameter resin pipe 1'at one end 1a thereof.
To the other end 1b. Here, the dielectric heating device 14
Will be described. 6 and 7 are schematic views of an induction heating device assembled with hollow conductors. In this device,
A plurality of circular spiral wire portions 14d are formed as electrodes without contacting each other with one hollow conducting wire 14c, and the distance between the circular spiral wire portions on the one end 1a side of the expanded diameter resin pipe 1 ′ is
It is narrower at an equal ratio than the distance between the circular spiral wire portions on the other end 1b side of the expanded diameter resin pipe 1 '. Here, the hollow portion of the hollow conductive wire 14c forming the circular spiral wire portion 14d is an outward hole of the cooling water circulated and supplied, and the circular spiral wire portion 14
The hollow portion of the hollow conductor 14c passing through the center of d is a return hole for cooling water, and each of them is connected to a cooling water circulating device (not shown). Further, the outer diameter of the circular spiral wire portion 14d is smaller than the inner diameter of the resin pipe 1 before the diameter expansion, and the inside of the circular spiral wire portion 14d has a flexible heat insulation such as glass fiber. The material 14e is filled and shaped into a bulk body as a whole.

This dielectric heating device 14 has an overall skeleton of 1
Since it has a circular spiral wire structure formed of two hollow conductors, it can be flexibly bent in the longitudinal direction. Therefore, even if the resin pipe is bent to some extent, 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 14f are machined with a non-perforated wire, and the circular electrode rings 14f are reduced at an equal ratio to each other on the one end 1a side of the diameter-expanding resin pipe than on the other end 1b side. The two non-hole conducting wires 14a, 14b are alternately arranged so that each circular electrode ring 14
f and the reinforcing wire 14g of each circular electrode ring,
It has a two-electrode structure electrically. If necessary, the inner space of the circular electrode ring 14f may be filled with a flexible heat insulating material such as glass fiber to shape the whole into a bulk body.

In these dielectric heating devices 14, when a predetermined high frequency voltage is applied from the high frequency power source 13, an electric field is generated between the circular electrodes. Then, in the diameter-expanded resin pipe 1 ′ that is close to these circular electrodes, the atoms and electrons of the constituent resin are polarized in the length portion corresponding to the interval between these circular electrodes, causing a friction heating phenomenon, The diameter resin tube 1'heats itself.

At this time, the temperature of the expanded resin tube 1'is adjusted by adjusting the output power from the dielectric heating device 14.
The temperature is set to a temperature equal to or higher than the melting point of the constituent resin. as a result,
While operating the dielectric heating device 14, the diameter-expanded resin pipe 1 '
When the wire is swept from one end 1a to the other end 1b, the diameter-expanded resin pipe 1 ′ sequentially self-heats from its one end 1a to a temperature equal to or higher than its own melting point and melts at the same time. Since the inner pressure for expanding the diameter of 1'is applied, the diameter-expanded resin pipe 1'is always kept pressed against the inner surface of the existing pipe 4.

In this process, the diameter-expanded resin pipe 1'is replaced by the existing pipe 4.
The internal residual stress generated at the time of adhesion due to softening / expansion of the inner surface of the tube is released, and in the state where the original shape restoring force is lost, the inner tube of the existing pipe 4 is pressed again and adheres thereto. Therefore, the diameter-expanded resin pipe 1 ′ is adhesively fixed to the inner surface of the existing pipe 4 in a shape memory state corresponding to the applied temperature, and does not shrink even in the cooling process.

For example, the above-mentioned caliber 150 mm, wall thickness 5 mm
Polyethylene pipe (density 0.946 g / cm ³ , melting point 130
C.) was once lined on the existing pipe 4 and then the dielectric heating device 14 was operated at 30 kW, the time required to reheat the polyethylene pipe from room temperature to 140 ° C. was within 2 minutes. It was Then, the expanded diameter resin tube 1 ′ after the treatment was allowed to cool naturally, and the amount of shrinkage in the radial direction after about 100 hours was measured. As a result, shrinkage of 1% or more on average was not observed. The contraction had stopped.

After terminating the running from the one end 1a to the other end 1b of the expanded resin tube 1'while operating the dielectric heating device 14, the operation of the dielectric heating device 14 is stopped and the pipe 11
From b, a pressure medium is pressed in and the internal pressure is maintained for a desired time, and the expanded diameter resin pipe 1'is allowed to cool, and the method of the present invention is completed. In addition, 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.
The high-frequency voltage may be applied so that the existing pipe 4 serves as one electrode and the circular electrode of the dielectric heating device serves as the other electrode.

Embodiment 2 FIG. 10 is a schematic view showing a case where an infrared ray generator 15 is used as a heating means. In this case, in place of the dielectric heating device 14 used in Example 1, an infrared ray generating device 15 to be described later was swept from one end 1a to the other end 1b of the diameter-expanding resin tube 1 ', and The construction method proceeds in the same manner as in Example 1.

As shown in the partially cutaway perspective view of FIG. 11, the infrared ray generator 15 includes a cylindrical body 15a made of, for example, stainless steel, an infrared radiation layer 15b formed on the outer periphery thereof, and an inside of the cylindrical body. It is composed of a thin tube 15c which is spirally wound around and arranged, and a heat insulating material 15d such as a glass fiber filled inside the cylindrical body. Examples of the infrared radiation layer 15b include a black oxide coating film formed by firing a stainless steel cylindrical body 15a at a temperature of 1000 ° C. or higher in the air, a black baking coating containing ceramics, cordierite, or aluminum titanate. The spray coating film of ceramics can be mentioned. Each of these layers can emit heat rays from far infrared rays to infrared rays.

Further, the thin tube 15c arranged in the cylindrical body 15a is made of, for example, stainless steel, and the center thereof has nichrome as a heating radiation source.
A core wire 15e made of tungsten, platinum or the like is wired, and a thin tube 15c is filled with an inorganic powder 15f such as magnesia. One end and the other end of the core wire 15e of the thin tube 15c are connected to a flexible covered electric wire 16 via a mounting plug 15g, and the covered electric wire 16 is connected to a power source 17.

In the case of this infrared generator 15, a power source 17
When the coated electric wire 16 is energized from the core wire 15e, the core wire 15e generates heat,
Due to the heat energy, infrared rays or far infrared rays having a predetermined wavelength are radiated from the infrared radiation layer 15b and reach the inner surface of the diameter-expanded resin pipe 1'located outside the device 15. 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
μHz, 14 μHz, etc.

Therefore, when the wavelength of infrared rays or far infrared rays radiated from the infrared radiation layer 15b 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 15
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.

[0032]

As is apparent from the above description, according to the method of the present invention, the infrared ray generating device or the infrared ray generating device is applied to the resin pipe lined with the inner surface of the existing pipe by expanding the diameter of the existing pipe while applying the internal pressure with the heating fluid. By running one of the dielectric heating devices, the expanded resin tube can be rapidly and reliably self-heated to a temperature above the melting point of its constituent resin.
The original shape restoring force of the diameter-expanded resin pipe is erased, and the internal residual stress generated at the time of diameter expansion is released, and as a result, the diameter-expanded resin pipe continues to memorize the shape at the applied temperature,
It does not cause shrinkage in the cross-sectional direction or shrinkage in the longitudinal direction after cooling.

[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 lining resin pipe of FIG. 3 is expanded in diameter to the inner surface of an existing pipe.

FIG. 5 is a partial enlarged view showing a state where the construction method of the present invention is carried out.

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 diameter-expanded resin pipe.

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]

 DESCRIPTION OF SYMBOLS 1 Resin pipe for lining 1'Expansion resin pipe 1a One end 1b of resin pipe 1 for lining 1 Other end of resin pipe 1 for lining 2 Pull-in rope 3 Winding winch 4 Existing pipe 5 Drum 6a Pipe 7 Heat medium generator 8a, 8b Inner taper pipe 9a, 9b Outer taper pipe 10a, 10b Jack 11a, 11b Piping 11c, 11d Valve 12 Heat medium generator 13 High frequency power supply 14 Dielectric heating device (heating means) 14a, 14b Conductor wire 14c Hollow conductor wire 14d Circular spiral wire part ( Circular electrode) 14e Heat insulating material 14f Circular coil (circular electrode) 14g Reinforcing wire 15 Infrared generator (heating means) 15a Cylindrical body 15b Infrared radiation layer 15c Capillary tube 15d Thermal insulation material 15f Core wire 15g Inorganic powder 16 Coated wire 17 Power source

 ─────────────────────────────────────────────────── ─── 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. An inside of an existing pipe in which a resin pipe for lining made of a crystalline thermoplastic resin is inserted into a pipe line of the existing pipe, and then the resin pipe for lining is softened / expanded to be in close contact with an inner surface of the existing pipe. In the surface lining method, both ends of the expanded resin tube are sealed and internal pressure is applied by a heating fluid, and while maintaining this state, an infrared generator or a dielectric is applied from one end to the other end of the expanded resin tube. A lining method for lining the inner surface of an existing pipe, characterized in that one of the heating means of the heating device is run and heated, and one end to the other end of the expanded resin pipe are sequentially heated to a temperature equal to or higher than the melting point of the constituent resin. .