JPH0586744B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to a pipe lining method.

Conventional technology and its problems Conventionally, as a method for lining existing pipes such as water pipes, a pipe body (inner pipe) with a diameter one step smaller than that of the pipe is inserted into the pipe to be lined (outer pipe). However, a so-called pipe-in-pipe construction method has been proposed in which the inner tube is lined and fixed within the outer tube by filling a bonding material such as mortar in the periphery between the inner and outer tubes. This conventional construction method has excellent construction reliability because the inner pipe retains its shape, but it has the following problems.

The effective diameter of the pipe after lining becomes the diameter of the pipe body which is one step smaller than this, and the reduction in effective diameter is large.

In addition to the pipe body, a bonding material such as mortar is required as a lining material, resulting in high material costs.

In addition to the labor involved in centering the pipe and filling the joint material such as mortar, it also takes time to cure and harden the joint material, which requires a large amount of manpower and time, resulting in poor workability.

If the tube has a bend, insertion of the tube becomes difficult and cannot be carried out.

Moreover, instead of such a pipe-in-pipe construction method, a tube lining method has been proposed in which a flexible elastic tube having approximately the same diameter as the pipe is inserted into the pipe to be lined and is bonded and integrated with the tube. This conventional construction method can eliminate the problems of the pipe-in-pipe construction method described above, but since the tube does not have shape retention, if there is even a part of the tube with poor adhesion, it will peel and the lining will not be able to maintain its condition. However, the problem was that the construction was unreliable.

The present invention has been made with the aim of eliminating such conventional problems.

Means for Solving the Problems The present invention involves inserting a shape-retaining thermoplastic synthetic resin tube with a smaller diameter than the tube over the entire length of the tube to be lined, and then inserting it into the tube. A tube expansion plug, which is equipped with a heat heater and a through hole penetrating in the tube axis direction, is installed in the base end of the tube, and then a plug is inserted into the tube from the base end side of the tube. While supplying pressurized air, a portion of the pressurized air is heated by the heater and flows out to the plug tip side through the through hole, and the pipe body is prepared by the heated pressurized air at the plug tip side. While continuing this preliminary heating and the heating of the tubular body by the heater, the tubular body is forcibly advanced from the proximal end toward the distal end using the tubular body. The present invention relates to a pipe lining method characterized in that the shape-retaining pipe expands in the pipe radial direction, and the expanded shape-retaining pipe is cooled while being pressed against the inner surface of the pipe by the pressurized air supplied into the pipe.

In the construction method of the present invention, a shape-retaining pipe body for lining is used, which corresponds to the inner pipe in the pipe-in-pipe construction method, and this pipe body is used for lining pipes such as water pipes and city gas pipes. After being inserted into a pipe such as a gas chamber pipe, a heated fluid transport pipe, or an exhaust dust pipe, the pipe body is heated and softened and expanded in the radial direction.The pipe body must be made of thermoplastic synthetic resin, such as polyester. An appropriate selection is made from vinyl chloride pipes, polyethylene pipes, polypropylene pipes, etc. In particular, when heat resistance and chemical resistance are required, such as for the lining of heated fluid transport pipes, heat-resistant materials such as polytetrafluoroethylene (trade name: Teflon), etc.
Use a material with good chemical resistance. As the tube, it is preferable to use a flexible tube in consideration of ease of insertion into the tube. The outer diameter of the tube body is not particularly limited as long as it does not interfere with insertion into the tube, but if the diameter is too small compared to the diameter of the tube, the expansion rate during lining operation will become large. This may lead to unfavorable results in terms of expansion work, so
It is appropriate to use a tube with a diameter as large as possible within the range that does not interfere with the insertion work into the tube, and usually one with an outer diameter (diameter) of about 9/10 to 1/10 of the inner diameter of the tube is used. The wall thickness of the tube must be within a range that allows it to retain its shape and maintain its strength even after expansion and lining, and is usually between 1 and 2.
It is determined as appropriate from a range of about 10 mm depending on the expansion ratio, diameter, material, etc.

The plug installed inside the tubular body functions as a stopper for pressurized air supplied into the tubular body in order to press the expanded tubular body against the inner surface of the tubular body, and also serves as a lining for the unexpanded tubular body that has been softened by heating. It functions as an expansion member to expand in the radial direction to a state close to that of the original state. The plug has an outer diameter (diameter) slightly smaller than the inner diameter of the expanded tube lining the tube, for example, by about 1 to 3 mm. The shape of the plug may be arbitrary, such as a ball or a gourd shape.

In the present invention, the plug is equipped with a heater and a through hole penetrating in the tube axis direction. The heater has the function of heating the tubular body when the tubular body is expanded by the plug;
It serves to heat a portion of the pressurized air supplied into the tube, and the heated pressurized air is sent through the through hole into the tube on the side beyond the plug, and is used as a preliminary heating source for the tube. be done.

In the construction method of the present invention, when the tube body is expanded in the tube radial direction by the plug, the tube body is heated by the heater provided in the plug while being preliminarily heated by heated pressurized air on the side ahead of the plug. The time required for heating and softening can be shortened compared to the case of heating with a heater alone, and the speed of movement of the plug within the tube, and therefore the construction efficiency, can be improved.

In addition, the preliminary heating source can be created by using the pressurized air necessary to maintain the shape of the tube after expansion and the heater provided in the plug, so special equipment for creating the preliminary heating source is required. The purpose of preliminary heating can be easily achieved in terms of equipment and operation without requiring any installation or operation.

In the present invention, the heater may be built into the plug or provided outside the plug.
Further, the plug may have a structure in which a large diameter portion and a small diameter portion are connected directly or via a heater.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

FIG. 1 schematically shows the process of inserting a shape-retaining tube 2 made of thermoplastic synthetic resin into a tube a to be lined, and the tube body 2 is pulled through a joint fitting 3 at its tip. coupled to rope 4 and winch 5
It is pulled into the tube a and inserted over its entire length. In this case, it is convenient to pass the wire 6 through the tube body 2 in advance, but this may be done after the tube body 2 is inserted. As pipe body 2, the outer diameter (diameter) is approximately 6/10 of the inner diameter of pipe a in the figure.
The case where one is used is shown.

Figure 2 shows the situation before starting the lining operation, and shows the situation before starting the lining operation.
An enlarged diameter portion 2a having approximately the same diameter as the tube a is formed by applying appropriate means to the proximal end portion of the tube body 2 after the inner insertion,
A plug 1B is installed within this enlarged diameter portion 2a, and a lid 7 is provided at the mouth end of the enlarged diameter portion 2a. Above lid 7
has a supply port 7a, through which the inside of the enlarged diameter section 2a is communicated with a pressurized air supply section 8. The plug 1B shown in the figure consists of a large diameter portion 1B ₁ on the proximal end side and a small diameter portion 1B ₂ on the distal end side, and the large diameter portion 1B ₁ has an outer diameter approximately equivalent to the inner diameter of the enlarged diameter portion 2a. , and the small diameter portion 1B ₂ has an outer diameter approximately corresponding to the inner diameter of the unexpanded tubular body 2. The large diameter portion 1B ₁ and the small diameter portion 1B ₂ are respectively provided with through holes 14 and 15 penetrating in the tube axis direction, and the large and small diameter portions 1
An electric heater 12 is provided between B ₁ and 1B ₂ ,
Cord 12 for connecting the heater 12 to a power source
a penetrates the lid 7 and is drawn out to the outside on the proximal end side. Furthermore, a lid 16 can be provided on the tube 2 on the tip side of the tube body 2 as required, and a rope 17 for plug pulling operation is drawn out through the lid 16.

When carrying out the construction method of the present invention, the heater 12 provided in the plug 1B is energized in the state shown in FIG.
The heater 12 generates heat when energized and heats the surrounding tubular body 2 at a temperature between the softening point and melting point of the tubular body 2, thereby softening it.

On the other hand, pressurized air is supplied from the supply section 8 into the enlarged diameter section 2a. This pressurized air serves to prevent the expanded diameter portion 2a, which is still in a softened state immediately after the diameter expansion, from deforming in the direction away from the state of being crimped to the pipe a, and to harden the expanded diameter portion 2a by air cooling. The pressure range is usually 0.5Kg/cm ² to 5Kg/cm ²
(gauge pressure).

Heating and softening of the tubular body 2 by the heater 12 and the enlarged diameter portion 2
Plug 1 while continuing to supply pressurized air to
When B is moved from the proximal end to the distal end by pulling the rope 17, the tube body 2 is expanded in the tube radial direction as the plug 1B moves, and is crimped against the inner surface of the tube a. This crimped state is maintained by the action of pressurized air. Plug 1B like this
By continuing to move inside the tube 2, the expanded shape-retaining tube 2 can be lined over the entire length of the tube a.

At this time, in the present invention, through holes 14 and 15 are provided in the large diameter portion 1B ₁ and the small diameter portion 1B ₂ of the plug 1B, respectively.
are formed, and large and small diameter portions 1B ₁ , 1
Since the electric heater 12 is provided between B _{and 2} ,
A part of the pressurized air supplied into the enlarged diameter part 2a of the tube body 2 is transferred from the through hole 14 of the large diameter part 1B ₁ to the large diameter part 1B 1 , the small diameter part 1B ₁ ,
The heater 12 enters the space 13 between 1B _{and 2} .
Through hole 15 of small diameter part 1B ₂ while being heated by
It flows into the unexpanded tube body 2 on the forward side through the tube body 2 and preliminarily heats it.

Therefore, while the plug 1B is moving within the tube body 2, the tube body 2, which has been preliminary heated by the heated pressurized fluid, is heated by the heater 12 around the heater 12. The tubular body 2 quickly reaches a softened state by heating, and the speed at which the plug 1B moves within the tubular body 2 can be made faster than in the case where preliminary heating is not performed, contributing to improvement in construction efficiency.

Moreover, the preliminary heat source can be generated by using the heater 12 provided in the plug 1B and the pressurized air necessary for pressurizing and crimping the tube body 2a after expansion. The purpose of preheating can be achieved without substantial additional burden.

4 and 5 show a pipe a having a bent pipe part _a1 ,
An example of the case where the construction method of the present invention is applied is shown.

In this construction method, it is necessary that the pipe body 2 has flexibility, and this flexible pipe body 2 is used to improve the passage of the pipe a to the curved pipe section _a1 . As shown in FIG. 4, for example, a heating roll 9 is used to flatten the material. Due to its flat shape and flexibility, the tubular body 2 after flattening is shaped like an arrow 10 shown in FIG.
It has flexibility in direction.

FIG. 5 shows the process of inserting the flattened tube body 2 into the tube a. In this insertion process, the tube body 2 can pass through the curved tube section _a1 of the tube a without any trouble due to its bendability. .

After inserting the pipe body 2 into the pipe a, by applying the construction method of the present invention described above, the lining with the expanded pipe body 2 is lined over the entire length of the pipe a, including the bent pipe part _a1 . can be administered.

In the construction method of the present invention, the wall thickness of the pipe body 2 used as the lining material is reduced by expanding in the pipe radial direction, but by anticipating the thickness reduction in advance, shape retention and predetermined strength can be maintained. The inner lining can be obtained by holding the pipe body 2.

Effects of the Invention According to the construction method of the present invention, the following effects can be obtained.

The effective diameter of the pipe a after lining becomes the diameter of the expanded lining tube body, and the reduction width of the effective diameter becomes smaller by the amount corresponding to the expansion.

Since the tube body is expanded and lined directly to tube a,
There is no need to use any bonding materials such as mortar, reducing material costs.

After the pipe is expanded and lined, it is only necessary to harden it by air cooling, so it has excellent workability and is particularly useful for long-span lining construction.

Since the method expands the tube body after heating and softening it,
The shape of the tube body when inserted into the tube a does not have to be circular; for example, in a tube with a bend, insertability can be ensured by flattening the tube body.

The inner lining formed by expanding the tube retains its shape and has excellent construction reliability.

Since main heating by a heater and preliminary heating by heated pressurized air are used together, the tubular body can be heated and softened quickly, and construction efficiency can be improved.

Since the preliminary heating source can be created without increasing the burden on equipment and operations, the increase in construction costs due to preliminary heating can be substantially eliminated.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view schematically showing the state of insertion of the pipe into a straight pipe, Fig. 2 is a longitudinal sectional view schematically showing the situation immediately before the start of the method of the present invention, and Fig. 3 is a longitudinal sectional view schematically showing the state of insertion of the pipe into a straight pipe. Fig. 4 is an explanatory diagram showing the flattening process of the pipe body applied to the construction method of the present invention, and Fig. 5 shows the flattened pipe body as a pipe with a bent pipe section. FIG. 2 is an explanatory diagram showing a situation in which the device is being inserted into the body. In the figure, 1B is a plug, 2 is a shape-retaining tube body, 1
2 is an electric heater, and 14 and 15 are through holes.

Claims (1)

[Claims] 1. Insert a shape-retaining thermoplastic synthetic resin tube with a diameter smaller than that of the tube over the entire length of the tube to be lined, and then insert the tube into the proximal end of the tube inserted into the tube. A tube expansion plug equipped with a heater and a through hole penetrating in the tube axis direction is installed, and then pressurized air is supplied from the proximal end side of the tube to the inside of the tube, and the pressurization is performed. A portion of the air is heated by the heater and flows out through the through hole toward the tip of the plug, and then the tube body is preliminarily heated by heated pressurized air at the tip of the plug, and this preliminary heating and the above-mentioned While continuing to heat the tubular body with the heater, the plug is forcibly advanced within the tubular body from the proximal end toward the distal end, thereby expanding the tubular body in the radial direction, and after expansion. A pipe lining method characterized in that the shape-retaining pipe body is cooled while being pressed and held on the inner surface of the pipe by the pressurized air supplied into the pipe body.