JPH11300832A - Resin pipe for lining steel pipe and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly bond a steel pipe and a resin pipe without generating a gap between the steel pipe and the resin pipe at a time of the bonding of both pipes and to prevent the generation of trouble such as peeling or expansion. SOLUTION: A hot melt adhesive is applied to the outer peripheral surface of a vinyl chloride resin pipe 2 having thermal expansion properties in its radial direction to form an adhesive layer 3 and a plurality of ridges continuing in the axial direction of the resin pipe 2 are formed to the outer peripheral surface 3a of the adhesive layer 3. If this lining resin pipe 1 is inserted into a steel pipe to be bonded to the steel pipe by heat treatment, air bubbles or void air generated at a time of heating simultaneously with the thermal expansion in the steel pipe escapes in a pipe axial direction by the ridges 4 on the outer peripheral surface of the adhesive layer 3 and the outer peripheral surface of the lining resin pipe 1 and the inner peripheral surface of the steel pipe can be mutually closely bonded without leaving air such as air bubbles between both surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin for lining a steel pipe having a hot-melt adhesive layer formed on an outer peripheral surface thereof, such as a lining resin pipe for coating an inner wall surface of a steel pipe such as a water pipe or a drain pipe. The present invention relates to a pipe and a method for manufacturing the pipe.

[0002]

2. Description of the Related Art In recent years, vinyl chloride resin pipes have been lined on the inner surface of steel pipes for water pipes and drainage pipes in buildings and the like, so that both the strength of iron and the corrosion resistance and chemical resistance of vinyl chloride resin have been achieved. A lining steel pipe having the advantages of the above is used.

[0003] As a method of manufacturing this lining steel pipe, an adhesive is applied to an outer peripheral surface of a vinyl chloride resin pipe which is an inner lining surface of the steel pipe, inserted into the steel pipe, and then the steel pipe is drawn or drawn. After the diameter is reduced by cold working, a method of obtaining a steel pipe and a vinyl chloride resin pipe by pressure contact, or after inserting a heat-expandable vinyl chloride resin pipe coated with an adhesive on the outer peripheral surface into the steel pipe, There is a method of bonding and fixing the inner surface of the steel pipe by heating and expanding the vinyl chloride resin pipe.

[0004]

However, in the above-mentioned conventional method for manufacturing a lining steel pipe, the steel pipe and the vinyl chloride resin pipe are bonded and fixed to each other with an adhesive. When the gap between the adhesive on the outer peripheral surface of the resin pipe inserted into the steel pipe and the inner peripheral surface of the steel pipe is narrowed during heating or thermal expansion, air such as air bubbles may remain.

[0005] When there is residual air or the like, the bonding state between the steel pipe and the resin pipe becomes non-uniform, that is, there is a possibility that poor adhesion occurs and a problem such as peeling occurs with the passage of time. In addition, corrosion may occur again between the peeled portion and the inner surface of the steel pipe, and further, the inner surface of the peeled portion between the resins may swell to obstruct the flow as a pipeline.

In order to solve the above-mentioned problems, the present invention does not generate a gap between the steel pipe and the resin pipe when the steel pipe and the resin pipe are bonded, so that the two pipes are securely bonded to each other. It is an object of the present invention to provide a resin pipe for steel pipe lining which does not cause problems such as peeling and swelling, and a method for manufacturing the same.

[0007]

Next, means for solving the above problems will be described with reference to the drawings corresponding to the embodiments. The resin pipe for steel pipe lining according to the present invention is a resin pipe for steel pipe lining 1 in which a hot-melt adhesive is applied to an outer peripheral surface 2a of a resin pipe 2 having a thermal expansion property in a radial direction and an adhesive layer 3 is formed. In addition, a plurality of ridges 4 that are continuous in the axial direction of the resin tube 2 are formed on the outer peripheral surface 3 a of the adhesive layer 3.

The resin pipe for lining a steel pipe according to the present invention has an outer peripheral surface 2a of a resin pipe 2 having a thermal expansion property in a radial direction.
Is coated with a hot-melt adhesive to form an adhesive layer 3. The outer peripheral surface 3 a of the adhesive layer 3 is continuous with the resin pipe 2 in the axial direction. It is characterized in that a plurality of concave grooves 5 are formed.

Further, according to the method for manufacturing a resin pipe for steel pipe lining of the present invention, the outer peripheral surface 2 of the heat-expandable resin pipe body 2 is continuously extruded and conveyed at a predetermined speed.
a, the molten hot-melt adhesive is continuously applied in the form of a film, and the uneven portions 1 b are formed on the inner peripheral edges 13 b and 23 b.
4 and 24 are passed through the bases 13 and 23 to form a continuous ridge 4 or a concave groove 5 in the tube axis direction on the outer peripheral surface of the applied adhesive to form the adhesive layer 3. It is characterized by gaining.

The method for manufacturing a resin pipe for lining a steel pipe according to the present invention is characterized in that the outer peripheral surface 2a of the thermally expandable resin pipe 2 which is continuously extruded and conveyed at a predetermined speed.
The melted hot-melt adhesive is continuously applied in the form of a film, and a projecting piece 2 is formed on the outer peripheral surface of the film by the adhesive.
5 is pressed to form a continuous groove 5 in the tube axis direction on the outer peripheral surface of the applied adhesive, thereby forming an adhesive layer 3.

According to such a configuration and a manufacturing method, the steel pipe lining resin pipes 1, 21 are inserted into the steel pipes, and then subjected to a treatment such as heating to bond the steel pipes to the lining resin pipes 21, 21. At this time, simultaneously with the thermal expansion in the steel pipe, air generated by air bubbles and gaps generated at the time of heating escapes in the pipe axis direction by the ridges 4 or the concave grooves 5 formed on the outer peripheral surface of the adhesive. The above effect can be obtained, and it is possible to adhere to each other in a close contact state without leaving air such as air bubbles between the outer peripheral surfaces of the lining resin tubes 1 and 21 and the inner peripheral surface of the steel pipe. From this, the steel pipe and the lining resin pipe 1, 21
Means that the adhesive is fixed securely, does not cause problems such as peeling, and does not cause bulging (bulging) of the inner surface of the tube.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, each embodiment will be described.

First Embodiment FIG. 1 is a schematic perspective view showing a first embodiment of a resin pipe for steel pipe lining according to the present invention, and FIG. 2 is an apparatus for manufacturing a resin pipe for steel pipe lining according to the first embodiment. It is a schematic side view.

The steel pipe lining resin pipe 1 of the first embodiment has a chlorinated resin having a thermal expansion property in a radial direction set to an outer diameter slightly smaller than the inner diameter of a steel pipe (not shown) to be lined. A resin tube 2 made of vinyl resin is used as a base material.

The outer peripheral surface 2a of the resin tube 2 is coated with, for example, a soft grade saturated copolymerized polyester resin hot melt adhesive having excellent adhesion to a vinyl chloride resin as a material of the resin tube 2. Thus, the adhesive layer 3 is formed substantially uniformly.

As shown in FIG. 1, the adhesive layer 3 has a plurality of ridges 4 formed on the outer peripheral surface 3a thereof along the tube axis direction of the resin tube 2.

The ridges 4 formed on the adhesive layer 3
The number is appropriately increased or decreased depending on the diameter of the resin tube 2. For example, when the nominal diameter is 15A and 20A, the number is four, and when the nominal diameter is 50A, the number is eight. It is formed on the outer peripheral surface 3a of the agent layer 3 so as to be substantially equally spaced.

The hot-melt adhesive forming the adhesive layer 3 is made of, for example, a saturated copolymerized polyester resin. As the hot-melt adhesive, PES-
111EE (trade name; manufactured by Toa Gosei Co., Ltd.) or a hot-melt adhesive made of an ethylene-vinyl acetate copolymer. 7554 (trade name; manufactured by Hirodyne Co., Ltd.) and Konishi No. MK-25 (trade name; manufactured by Konishi Co., Ltd.) and the like.

Then, this hot melt adhesive is melted by an adhesive ruder and formed into a substantially uniform film on the outer peripheral surface 2a of the resin tube 2 by using a mold so that the adhesive layer 3 is obtained. It has become.

Next, a schematic configuration of a manufacturing apparatus 7 used for manufacturing the resin pipe 1 for steel pipe lining will be described.

As shown in FIG. 2, the manufacturing apparatus 7 is generally constituted by an extruder 8, a cooling water tank 9, an adhesive ruder 10, a mold 12, and a reheating furnace 15.

The extruder 8 is supplied with a pellet or a powdery vinyl chloride resin as a material of the resin tube 2 as a base material, and heats and softens and melts the resin material.
This resin material is extruded from a mold constituted by an annular die to continuously form a resin tube 2 having a hollow circular cross section.

The cooling water tank 9 is disposed adjacent to the extruder 8, cools the resin tube 2 molded by the extruder 8, and slightly reduces the diameter of the heated resin tube 2 immediately after molding. That is, the molded resin tube 2 has thermal expansion properties in the radial direction.

The adhesive melter 10 is supplied with a hot-melt adhesive in the form of pellets or powder, for example, and heats and melts the adhesive. The melt adhesive is continuously extruded in a molten state.

The mold 12 is disposed adjacent to the cooling water tank 9 and has a transport path penetrating the center. This conveying path is a through hole having a circular cross section, and is set to have an inner diameter slightly larger than the outer diameter of the resin pipe 2 formed in the cooling water layer 9, and the outlet of the conveying path which is the tip of the mold 12. A base 13 is provided on the side.

The mold 12 is provided around a central conveyance path.
The flow path is formed in an annular shape. A part of the base end of this flow path is provided with a connection flow path that opens to the outer surface of the mold 12, and the heat hose 11 of the adhesive ruder 10 is connected to this connection flow path and is melted. Adhesive is sent in. A slit-shaped outlet is formed at the end of the mold 12 around the outlet 12a of the transport path at the center of the mold 12, and is opened concentrically. The slit is located around the outlet. The base 13 is provided as described above. The slit interval of the outlet is set to a uniform interval, and the adhesive extruded from the outlet is formed into a ring shape and is formed into a film shape and applied to the surface of the resin pipe 2.

As shown in FIG. 3, the base 13 is a plate-like member having a substantially circular through hole 13a formed in the center. The inner diameter of the through hole 13a is formed to be slightly larger than the outer diameter of the resin tube 2 entering the mold 12, and is coaxial with the resin tube 2, that is, from the outer peripheral surface 2a of the resin tube 2 to the base. The gap distance between the inner peripheral edge 13b and the inner peripheral edge 13b is substantially uniform in the circumferential direction.

As shown in FIG. 3, concave portions 14 are formed at equal intervals from each other on the inner peripheral edge 13b of the through hole 13a of the base 13. As shown in FIG.

The shape of the through hole 13a and the concave portion 14 of the base 13 is such that the gap from the outer peripheral surface 2a of the resin tube 2 passing through the through hole 13a to the inner peripheral edge 13b of the through hole 13a is 50 to 150 μm, preferably 100 μm. The depth of the recess 14 is 50 to 100 μm, and the width of the recess 14 is 0.5 to 2
mm, and in the present embodiment, four portions are formed at equal intervals.

Although not shown, the mold 12 has
A suction pump such as a vacuum pump is connected to lower the pressure in the space between the inner peripheral surface in the mold 12 and the outer peripheral surface 2a of the resin tube 2 so that an annularly formed film-like adhesive is applied to the resin tube. The outer peripheral surface 2a of the second member 2 is brought into close contact with the outer peripheral surface 2a. Further, the mold 12 is provided with a fine adjustment mechanism such as an adjustment bolt so that the distance between the base 13 and the resin pipe outer peripheral surface 2a can be finely adjusted.

Next, as shown in FIG. 2, the reheating furnace 15 is arranged following the mold 12, and the resin tube 2 having the adhesive coated on the outer peripheral surface 2a by the mold 12 is loosely inserted. ,
Resin tube 2 that can pass through, that is, coated with adhesive
It has a penetrating portion formed with an inner diameter slightly larger than the outer diameter of the above, and is provided with a heater on the inner peripheral surface.

The inside of the reheating furnace 15 is heated to a predetermined temperature by a heater and maintained at the predetermined temperature, and the adhesive on the outer peripheral surface 2a of the resin tube 2 moving in the through portion is provided. Is heated and crystallized to make the adhesion with the resin tube 2 more complete.

Although not shown, a cutting portion or the like is arranged following the reheating furnace 15, and the resin tube 2 on which the adhesive layer 3 is formed is separated by a predetermined length. It is designed to be cut with a push-cut disk-shaped cutter.

Next, the manufacturing apparatus 7 configured as described above
A method of manufacturing the resin pipe 1 for steel pipe lining according to the first embodiment will be described.

First, a pellet or a powdery vinyl chloride resin as a material of the resin tube 2 is heated and softened and melted by the extruder 8, and the resin is extruded from a mold of an annular die to form a hollow circular resin tube. 2 are continuously formed.

The resin tube 2 immediately after molding is then passed through a sizing die, and is cooled by cooling water by passing through a cooling water tank 9, and is extruded from an extruder 8 by this diameter reducing cooling action. Immediately after molding, the diameter is reduced by several percent and molded.

Next, the resin tube 2 enters the conveying path of the mold 12. At the same time, the hot melt-based adhesive melted by heating is fed into the flow path in the mold 12 through the heat hose 11 from the adhesive ruder 10 connected to the mold 12, and is extruded from the outlet. At this outlet,
The adhesive in the molten state is formed into an annular film shape,
2 outer peripheral surface 2 of the resin pipe 2 carried out from the outlet of the conveying path 2
Extruded continuously to a.

At the same time, by operating the suction pump, a film-like adhesive is provided between the outer peripheral surface 2a of the resin tube 2 in the mold 12 and the inner peripheral surface of the mold conveying path and on the outlet side. The pressure in the enclosed space is lowered, whereby the adhesive in the form of an annular film extruded from the outlet is brought into close contact with the outer peripheral surface 2a of the resin tube 2 and is applied. The outer peripheral surface 2a is formed into a layer having a substantially uniform thickness.

At the same time, the adhesive applied to the outer peripheral surface 2a of the resin pipe 2 in a film-like form is passed through the die 13 provided at the outlet of the mold 12 so as to narrow the adhesive so as to narrow the adhesive. The protrusions 4 are formed on the outer peripheral surface 3a of the adhesive layer 3 by the concave portions 14 formed on the inner peripheral edge 13b of the die 13.

Next, the resin tube 2 coated with the adhesive having the ridges 4 enters the through portion of the reheating furnace 15 and is subjected to heat treatment by a heater in the through portion. Thereby, crystallization of the hot-melt adhesive is promoted, and the adhesion to the vinyl chloride resin, which is a material of the resin pipe, is improved, and the adhesive layer 3 is formed, whereby the resin pipe 1 for steel pipe lining is obtained.

Thereafter, after the adhesive layer 3 is subjected to a drying treatment, etc., the lining resin tube 1 which is conveyed to the cutting section and conveyed continuously is cut and formed by a cutter at predetermined lengths.

Accordingly, this resin pipe 1 for steel pipe lining
Is bonded and fixed to the inner surface of the steel pipe, the resin pipe 1 for steel pipe lining is inserted into the steel pipe, and then, high-frequency heating treatment or the like is performed along the axial direction of the steel pipe, so that The lining resin pipe 1 undergoes thermal expansion in the radial direction, and the lining resin pipe 1 is bonded to the inner peripheral surface of the steel pipe by a hot melt adhesive.

Since a plurality of ridges 4 are formed on the adhesive layer 3 applied to the outer peripheral surface of the lining resin tube 1 at the time of bonding, air bubbles generated at the time of heating escape in the axial direction. Thus, the lining resin tube 1 is adhered in a close contact state without leaving air such as air bubbles between the outer peripheral surface of the lining resin pipe 1 and the inner peripheral surface of the steel pipe.

Thus, the steel pipe and the lining resin pipe 1
Are securely bonded and fixed, and no trouble such as peeling occurs, and swelling of the inner surface does not occur.

According to the resin pipe 1 for lining steel pipes, since a plurality of ridges 4 are formed on the outer peripheral surface, these ridges 4 serve as buffer portions, and can buffer the steel pipe at the time of insertion. Also, it becomes a buffering part when inserted into the steel pipe, and can provide a buffering effect against an impact during transportation in a state where the lining resin pipe 1 is inserted into the steel pipe before the heat bonding process, and the lining resin is formed inside the steel pipe. The tube 1 is not damaged.

In the first embodiment, as a means for forming the ridge 4 on the hot melt adhesive applied to the outer peripheral surface 2a of the resin tube 2, the base 13 mounted on the mold 12 is used. In this embodiment, the die 13 is formed separately from the die 14, but the slit-shaped outlet of the die 12 is used as a die. May be provided to form the ridge 4.

Second Embodiment FIG. 4 is a schematic perspective view showing a second embodiment of a resin pipe for steel pipe lining according to the present invention, and FIG. 5 is an apparatus for manufacturing a resin pipe for steel pipe lining of the same embodiment. It is a front view of the base used. In addition, the same code | symbol is attached | subjected and demonstrated to the same or equivalent part as the resin pipe 1 for steel pipe lining in 1st Embodiment mentioned above, and its manufacturing apparatus 7.

The resin pipe 21 for steel pipe lining according to the second embodiment has an outer diameter slightly smaller than the inner diameter of the steel pipe to be lined, similarly to the first embodiment. A resin tube 2 made of a vinyl chloride resin having thermal expansion property is used as a base material.

On the outer peripheral surface 2a of the resin tube 2, for example, a soft grade saturated copolymerized polyester resin hot melt adhesive having excellent adhesion to a vinyl chloride resin as a material of the resin tube 2 is applied. Thus, the adhesive layer 3 is formed substantially uniformly.

As shown in FIG. 4, the adhesive layer 3 has a plurality of concave grooves 5 formed on the outer peripheral surface 3a thereof along the tube axis direction of the resin tube 2.

The groove 5 formed in the adhesive layer 3
The number is appropriately increased or decreased depending on the diameter of the resin tube 2. For example, when the nominal diameter is 15A and 20A, the number is four, and when the nominal diameter is 50A, the number is eight. It is formed on the outer peripheral surface 3a of the agent layer 3 so as to be substantially equally spaced.

The hot melt adhesive forming the adhesive layer 3 is, for example, made of a saturated copolymerized polyester resin in the same manner as in the first embodiment. , PES-111EE (trade name; manufactured by Toa Gosei Co., Ltd.), or a hot melt adhesive made of an ethylene-vinyl acetate copolymer. The hot melt adhesive may be Hirodine N.
o. 7554 (trade name; manufactured by Hirodyne Co., Ltd.) and Konishi No. MK-25 (trade name; manufactured by Konishi Co., Ltd.) and the like.

Then, the hot melt adhesive is melted by an adhesive ruler and formed into a substantially uniform film on the outer peripheral surface 2a of the resin tube 2 by using a mold.

Next, a schematic configuration of a manufacturing apparatus used for manufacturing the resin pipe 21 for steel pipe lining of the second embodiment will be described.

This manufacturing apparatus comprises an extruder, a cooling water tank,
It is roughly composed of an adhesive ruder, a mold, and a reheating furnace.

The extruder, the cooling water tank, the adhesive ruder and the reheating furnace in this manufacturing apparatus have the same structure as those of the manufacturing apparatus in the first embodiment. , And the description thereof will be omitted with reference to FIG.

The mold 22 constituting the manufacturing apparatus 7 of the second embodiment is similar to that of the first embodiment described above.
A transport path 22a is provided adjacent to the cooling water tank 9 and penetrates the center. The conveying path 22 a is a through hole having a circular cross section, and is set to have an inner diameter slightly larger than the outer diameter of the resin tube 2 molded by the extruder 8. Is provided with a base 23.

This mold 22 is placed around a central conveyance path.
A flow path is formed in an annular shape, and a part of the base end of the flow path is provided with a connection flow path that opens to the outer surface of the mold 22. Hose 1
1 are connected so that the molten adhesive can be fed. A slit-shaped outlet is formed at the front end of the mold 22 around the outlet of the conveying path at the center of the mold, and is opened concentrically so as to be located around the outlet. A base 23 is provided. The slit interval of the outlet is set to a uniform interval, and the adhesive extruded from the outlet is formed into a ring shape and is formed into a film shape and applied to the surface of the resin pipe 2.

As shown in FIG. 5, the base 23 is a plate-like member having a substantially circular through hole 23a formed in the center. The inner diameter of the through hole 23a is formed to be slightly larger than the outer diameter of the resin tube 2 entering the mold, and is coaxial with the resin tube 2, that is, from the outer peripheral surface 2a of the resin tube 2 to the base 23. The gap distance to the inner peripheral edge 23b is substantially uniform in the circumferential direction, and is provided in the mold.

The inner peripheral edge 23b of the through hole 23a of the base 23 is formed at equal intervals from each other.
A plurality of protrusions 24 extending in the direction of the center of 3a are provided.

The shape of the through hole 23a and the projection 24 of the base 23 is such that the gap from the outer peripheral surface 2a of the resin tube 2 passing through the through hole 23a to the inner peripheral edge 23b is 50 to 150.
μm, preferably 100 μm, the height (extended length) of the projections is set to 50 to 100 μm, and the width of the projections is set to 0.5 to 2 mm. In the present embodiment, four portions are formed at regular intervals. Have been.

Next, the manufacturing apparatus 7 configured as described above
Pipe 21 for steel pipe lining according to the second embodiment
A method of manufacturing the device will be described.

First, the extruder 8 heats and softens and melts the pellet or powder-like vinyl chloride resin used as the material of the resin tube 2, extrudes the resin from a mold of an annular die, and forms a hollow circular resin tube. 2 are continuously formed.

The resin tube 2 immediately after molding is then passed through a sizing die, and is cooled by cooling water by passing through a cooling water tank 9, and is extruded from the extruder 8 by this diameter-reducing cooling action. Immediately after molding, the diameter is reduced by several percent and molded.

Next, the resin pipe 2 enters the conveying path of the mold 22. At the same time, the hot-melt adhesive that has been heated and melted is sent into the flow path in the mold 22 via the heat hose 11 from the adhesive ruder 10 connected to the mold, and is extruded from the outlet. At the outlet, the adhesive in a molten state is formed into an annular film shape, and is continuously extruded to the outer peripheral surface 2a of the resin tube 2 which is carried out from the outlet of the conveying path of the mold 22.

At the same time, by operating the suction pump, a film-like adhesive is formed between the outer peripheral surface 2a of the resin tube 2 in the mold 22 and the inner peripheral surface of the mold conveying path and on the outlet side. The pressure in the enclosed space is lowered, whereby the adhesive in the form of an annular film extruded from the outlet is brought into close contact with the outer peripheral surface 2a of the resin tube 2 and is applied. The outer peripheral surface 2a is formed into a layer having a substantially uniform thickness.

At the same time, the adhesive applied to the outer peripheral surface 2a of the resin tube 2 in a film form is passed through the die 23 provided at the outlet of the die 22 so as to narrow the adhesive to a uniform thickness. The protrusions 24 formed on the inner peripheral edge 23b of the base 23 form the concave grooves 5 on the outer peripheral surface of the adhesive.

Next, the resin pipe 2 coated with the adhesive having the continuous concave grooves 5 enters a through portion of the reheating furnace 15 and is subjected to heat treatment by a heater in the through portion. .
Thereby, the crystallization of the hot-melt adhesive is promoted, the adhesion to the vinyl chloride resin as a material of the resin tube 2 is improved, and the adhesive layer 3 is formed, whereby the resin tube 21 for steel pipe lining is obtained. .

After the adhesive layer 3 is dried, the lining resin tube 21 which is conveyed to the cutting section and conveyed continuously is cut and formed by a cutter at predetermined lengths.

Accordingly, the steel pipe lining resin pipe 21
Is bonded and fixed to the inner surface of the steel pipe, the resin pipe 21 for steel pipe lining is inserted into the steel pipe, and then, high-frequency heating treatment or the like is performed along the axial direction of the steel pipe, so that The lining resin pipe 21 undergoes thermal expansion in the radial direction, and the lining resin pipe 21 is bonded to the inner peripheral surface of the steel pipe by a hot melt adhesive.

Since a plurality of concave grooves 5 are formed in the adhesive layer 3 applied to the outer peripheral surface of the lining resin tube 21 at the time of bonding, air bubbles and the like generated during heating are removed by the concave grooves 5. In this case, the lining resin tube 21 is adhered in a close contact state without leaving air such as air bubbles between the outer peripheral surface of the lining resin tube 21 and the inner peripheral surface of the steel pipe.

Thus, the steel pipe and the lining resin pipe 2
1 is securely bonded and fixed, and no trouble such as peeling occurs, and swelling of the inner surface does not occur.

According to the steel pipe lining resin pipe 21, since the plurality of concave grooves 5 are formed on the outer peripheral surface, these concave grooves 5 serve as buffer portions, so that the impact at the time of inserting the steel pipe can be reduced. In addition, it becomes a buffer portion when inserted into a steel pipe, and can provide a buffering effect against an impact during transportation in a state where the lining resin pipe 21 is inserted into the steel pipe prior to the heat bonding treatment, so that the lining inside the steel pipe can be obtained. The resin pipe 21 is not damaged.

In the above-described second embodiment, as a means for forming the concave groove 5 in the hot melt adhesive applied to the outer peripheral surface 2a of the resin tube 2, the die 23 attached to the die 22 is used. In the above, an example is described in which the die 23 is formed separately from the die 22. However, the slit-shaped outlet of the die is used as the die, and the peripheral portion of the outlet is formed. May be provided with a convex portion 24 to form a concave groove.

In the above-described second embodiment, the concave groove 5 formed in the adhesive on the outer peripheral surface 2a of the resin pipe is formed by the mold 2
2, the adhesive layer 3 is used.
The example in which the concave groove 5 is formed at the same time as the molding is described. However, as shown in FIG. 6, a plurality of brackets 27 extending in an arm shape along the axial direction are provided on the outlet side of the mold 22. The tip of the bracket 27 has a knife-like projection 25.
May be attached, and the tips of the protruding pieces 25 may be disposed so as to be pressed against the adhesive applied to the surface of the resin tube 2.

That is, in the mold 22, the outer surface 2a of the resin tube 2 is made to have a uniform thickness at the outlet.
An adhesive is applied on the outer surface 2a of the resin tube 2 to form a film-like adhesive layer 3. As shown in FIG. 25, the tips formed at the acute angles of the projecting pieces 25 are arranged so as to face the center direction, and the distance from the resin pipe outer peripheral surface 2a to the tip of the projecting piece 25 is set to a predetermined distance. The configuration is such that the concave groove 5 is formed.

In the case of the configuration using the protruding pieces 25, since the adhesive applied in the form of a film has not yet dried and solidified, the concave groove 5 is cut and formed. This concave groove 5 is formed continuously in the tube axis direction of the resin tube 2.

Further, in the case of the configuration in which the protruding piece 25 is provided,
A plurality of knife-shaped protruding pieces 25 are provided not on the outlet side of the mold 22 but on the penetration side entrance side of the reheating furnace 15 or on the penetration side exit side of the reheating furnace 15 in the same manner as described above. It may be configured.

[0079]

As described above, in the resin pipe for lining a steel pipe according to the present invention, a ridge or a groove continuous in the pipe axis direction is formed on the outer peripheral surface of the adhesive layer.
After being inserted into the steel pipe, by performing processing such as heating in the steel pipe, when bonding the steel pipe and the lining resin pipe, simultaneously with the radial thermal expansion in the steel pipe, due to bubbles and gaps generated during heating Air escapes in the direction of the pipe axis, that is, the effect of air release is obtained, and these bubbles adhere to each other without leaving air such as air bubbles between the outer peripheral surface of the lining resin pipe and the inner peripheral surface of the steel pipe. Therefore, there is an effect that the reliability as a product can be improved.

As a result, the steel pipe and the lining resin pipe are securely bonded and fixed to each other, so that there is no problem such as peeling or the like, and there is no swelling (bulging) of the inner surface of the pipe. can get.

Further, according to the resin pipe for steel pipe lining of the present invention, since a plurality of ridges or grooves are formed on the outer peripheral surface of the adhesive layer, these ridges or grooves serve as buffer portions. It is possible to alleviate the impact during transportation after becoming a product, and it is possible to obtain the effect that damage such as cracking of the resin pipe for steel pipe lining is less likely to occur and also to reduce the impact when inserting the steel pipe. Also, it becomes a buffering part even when inserted in the steel pipe, and a buffering effect against an impact in the case where the lining resin pipe is inserted into the steel pipe before carrying out the heat bonding process is obtained, so that a shock absorbing effect can be obtained. Thus, the effect that the lining resin pipe is not broken can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing a first embodiment of a resin pipe for steel pipe lining according to the present invention.

FIG. 2 is a schematic side view of the apparatus for manufacturing a resin pipe for steel pipe lining according to the embodiment.

FIG. 3 is a front view of a base constituting the manufacturing apparatus.

FIG. 4 is a schematic perspective view showing a second embodiment of the resin pipe for steel pipe lining according to the present invention.

FIG. 5 is a front view of a base used in the apparatus for manufacturing a resin pipe for steel pipe lining of the embodiment.

FIG. 6 is a partially enlarged side view of an apparatus for manufacturing a resin pipe for steel pipe lining according to another embodiment.

[Explanation of symbols]

 1, 21 ... resin pipe for lining steel pipe 2 ... resin pipe 2a ... outer peripheral surface 3 ... adhesive layer 3a ... outer peripheral surface 4 ... ridge 5 ... concave groove 13, 21 ... base 13b, 23b ... inner peripheral edge 14 ... concave portion 24 ... Convex part 25: protruding piece

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F16L 58/10 F16L 58/10 // B29L 9:00 23:00

Claims (4)

[Claims] 1. A resin pipe for lining a steel pipe in which a hot-melt adhesive is applied to an outer peripheral surface of a resin pipe having a thermal expansion property in a radial direction, and an adhesive layer is formed. A resin pipe for lining a steel pipe, wherein a plurality of ridges continuous in the axial direction of the resin pipe are formed on an outer peripheral surface. 2. A resin pipe for lining a steel pipe in which a hot-melt adhesive is applied to an outer peripheral surface of a resin pipe having a thermal expansion property in a radial direction to form an adhesive layer. A resin pipe for lining a steel pipe, wherein a plurality of concave grooves continuous in the axial direction of the resin pipe are formed on an outer peripheral surface. 3. A molten hot-melt adhesive is continuously applied on the outer peripheral surface of a heat-expandable resin pipe body which is continuously extruded and conveyed at a predetermined speed in a film form. Passing a base having an uneven portion formed on the inner peripheral edge thereof, forming a continuous ridge or groove in the tube axis direction on the outer peripheral surface of the applied adhesive, and forming an adhesive layer to obtain the adhesive. A method for producing a resin pipe for a steel pipe lining. 4. A hot-melt adhesive that is continuously extruded and melted is applied to the outer peripheral surface of a thermally expandable resin tube conveyed at a predetermined speed in a film form. A protruding piece is pressed against the outer peripheral surface of the film made of the adhesive to form a continuous groove in the tube axis direction on the outer peripheral surface of the applied adhesive, thereby obtaining an adhesive layer. Of manufacturing resin pipe for steel pipe lining.