JP2002267059A - Resin tube for burying pipe, and execution method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin tube capable of avoiding the effect of any damage on the resin tube caused by soil during the backfill in a construction method for cut-and-cover and installation of a burial part, preventing any damages on a resin tube body when installing the resin tube by a non-cut-and-cover construction method such as a flow-mall method, and preventing disorder and disconnection of a locating wire. SOLUTION: A conductive wire 3 is disposed along the axial direction of the resin tube body 1, a cover tube 2 is melted and laminated on the outer circumference of the resin tube body through extrusion molding, and the resin tube body and the conductive wire are protected by this cover tube 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin pipe used for burying a pipe and a method for installing the same.

[0002]

2. Description of the Related Art Recently, as a method of laying pipes in which resin pipes are buried in the ground, such as upper and lower water distribution pipes, gas pipes, etc., there is a method of digging a buried portion of the pipe from the ground and laying the pipe. A non-cutting method called “flow molding method” disclosed in Japanese Patent No. 38598/38 is used.

In the laying method in which the buried portion is cut and cut, especially in a flexible polyolefin pipe, a resin pipe is conventionally used to prevent a sharp stone from biting into the pipe body to prevent the outer circumference of the pipe body from being damaged. Prior to laying, it is necessary to lay back material such as mountain sand and recycled sand at the bottom of the resin pipe, and to lay improved soil for the top laying. In addition, in preparation for repair work, a locating wire for detecting the buried position is fixed with tape or the like and is routed along the resin pipe.

On the other hand, in the non-cutting method, pits are provided at both ends of the laid portion, and a drill is started by a propulsion device installed on the ground near one of the pits, and is guided to the other pit by the guidance of a tip position detector on the ground. After that, a resin pipe is connected to the tip of the drill and pulled into the starting pit. Thereafter, the incoming pipe is joined to the existing pipe to form a pipe.

However, in the above method, the pipe is drawn in.
Due to contact with sharp stones or concrete pieces, or existing metal pipes, sharp scratches are likely to occur on the outer circumference of the pipe in parallel with the pipe axis. In water distribution and gas applications where an internal pressure is applied, such flaws start from the flaw and expand in the thickness direction and eventually penetrate, resulting in water or gas leakage.

Further, in the above-mentioned method, when the locating wire fixed with the tape is pulled in at the same time, the fixing tape is cut and the wire is disturbed and / or the wire is broken and cut. Come.

Japanese Patent Application Laid-Open No. Hei 5-106779 discloses a protective cover and an outer surface provided with a locating wire holding portion to protect the pipe body and the locating wire.

However, in the above method, a notch is formed in the longitudinal direction so that the cover can be covered even after the cover is buried, and is suitable for an open-cutting method, but in a non-cutting method involving drawing in, the cover itself is formed at the cutout. Drop, and the locating wire holding portion is located on the outer peripheral surface of the cover, so that a large resistance is generated in the drill hole, the holding portion is damaged, and the effect is lost.

In order to prevent the pipe from being damaged by the non-cutting method,
For example, Japanese Patent Application Laid-Open No. Hei 10-246359 discloses a resin tube having a resin surface layer in a non-adhered state, and proposes that the surface layer is made of polyamide or vinyl chloride. However, when a polyolefin pipe is used for the pipe main body, it is necessary to remove the entire surface layer when performing the processing after moating, resulting in a large cost. Further, the publication does not describe means for preventing disconnection of a locating wire.

On the other hand, in order to prevent disconnection of the locating wire, for example, JP-A-8-219334 discloses that a conductive wire as a locating wire is sandwiched between a coating layer and a tube body. In the above configuration, when a coating layer formed into a tubular shape in advance is used, the locating wire can be sandwiched between the pipe body and the coating layer.

However, in a resin pipe in which a coating layer is melt-laminated on the outer periphery of a tube main body by extrusion molding, it is difficult to sandwich the locating wire between the tube main body and the molten coating layer. No layer is formed. Further, in this publication, the covering layer is intended to fix the locating wire and bury it smoothly, and does not describe the protection itself of the resin pipe main body.

When a butt-welded tube is used, the locating wire also needs to be sequentially joined, and the joining portion has a larger diameter than the non-joining portion, and the resistance at the time of drawing in increases. A large load is generated at the joint, and the joint lacks reliability.

[0013]

DISCLOSURE OF THE INVENTION The present invention has been made in view of such circumstances, and in a method of digging and laying a buried portion, the resin tube is not damaged due to soil at the time of backfilling. In order to avoid the effects, it is possible to reduce the construction cost by returning to the original soil without using sand or improved soil as in the past, while on the other hand when laying resin pipes by non-cutting method such as flow molding method It is an object of the present invention to provide a resin pipe which prevents damage to a resin pipe main body and prevents disturbance of a locating wire and disconnection.

[0014]

Means for Solving the Problems The present invention has been made to achieve this object, and a first invention is a resin pipe main body and a conductive pipe disposed along the axial direction of the resin pipe main body. A resin tube for burying a pipe, comprising: a wire; and a coating layer, which is melted and laminated on the outer periphery of the resin tube main body so as to be peelable by extrusion and protects the resin tube main body and the conductive wire.

According to a second aspect of the present invention, there is provided a resin pipe main body, a conductive wire disposed and fixed along an axial direction of the resin pipe main body, and a coating melt-laminated by extrusion molding on the outer circumference of the resin pipe main body. 2. The resin pipe for burying pipes according to 1, comprising a layer.

According to a third aspect of the present invention, there is provided a resin pipe main body, a conductive wire holding portion disposed and fixed along an axial direction of the resin pipe main body, a conductive wire housed in the holding portion, 2. The resin pipe for burying pipes according to 1, comprising a coating layer melt-laminated by extrusion molding on an outer periphery of the pipe main body.

According to a fourth aspect of the present invention, a groove-shaped conductive wire holding portion parallel to the pipe axis of the resin pipe main body is formed on the outer surface of the coating layer, and the groove-shaped conductive wire holding portion has an opening on the outer surface of the coating layer. 2. The resin pipe for burying piping according to 1, wherein the portion is narrower than the inside.

According to a fifth aspect of the present invention, an elongated conductive wire holding portion parallel to the pipe axis of the resin pipe main body is formed inside the coating layer.
The resin pipe for burying a pipe according to the above.

A sixth invention is the resin pipe for embedding piping according to any one of 1 to 5, wherein the coating layer is formed of a material through which the pipe body can be seen.

A seventh aspect of the present invention is the resin pipe for burying a pipe according to any one of 1 to 6, wherein the conductive wire and / or the conductive wire holding portion is fixed with a tape.

According to an eighth aspect of the present invention, the resin tube according to any one of claims 1 to 7, wherein the resin tube body is a polyolefin resin.

A ninth invention is the resin pipe for burying pipes according to any one of 1 to 7, wherein the coating layer is a polyolefin resin of a different material from the resin pipe main body.

According to a tenth aspect of the present invention, the resin tube according to any one of claims 1 to 8, wherein the resin layer has a thickness exceeding 1.5 mm.

An eleventh invention is the resin pipe for burying a pipe according to any one of 1 to 10, further comprising an exposed portion which is not covered at an end of the resin pipe main body.

A twelfth invention is the resin pipe for burying a pipe according to any one of 1 to 11, wherein a conductive wire disposed on the resin body projects from an end of the resin pipe body.

According to a thirteenth aspect, the invention is characterized in that an easy-peeling portion is previously provided on the coating layer over the end portion and / or the entire length of the resin tube main body.
3. The resin pipe for burying a pipe according to any one of 2.

According to a fourteenth aspect of the present invention, after the covering portion near the connection portion is peeled off and butt fusion or fusion bonding using a joint,
Protect the connection by covering the connection with a covering member
14. The method for constructing a resin pipe for burying a pipe according to any one of 13 to 13.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, the resin tube according to the present invention is required to have flexibility, and is preferably a polyolefin. Further, it is desirable that butt fusion bonding is possible, and examples of applicable resins include polyethylene, polypropylene, and polybutene.

In consideration of the post-hoiling treatment, the coating layer according to the present invention is easier to treat with a polyolefin-based resin. Particularly, when used as a fuel, the coating layer and the pipe main body composed of the polyolefin resin are separated. Desirable because there is no need. However, if the same olefin resin as the tube is used, fusion of the coating layer and the tube body may occur depending on the manufacturing method, and the coating layer may not be peelable.
It is preferable to use a type different from the resin tube main body for the coating layer. When the tube body uses a polyethylene resin, it is desirable to use a polypropylene homopolymer and / or copolymer resin or the like having a high hardness and a high protection function for the coating layer.

The thickness of the coating layer should be at least 1.5 m to prevent the pipe body and the locating wire from being damaged.
m and more than 2 mm is more desirable when sharp gravel is mixed.

For non-cutting, especially in the flow molding method,
When using a butt-fused tube, protection of the butt joint and the tubing near the butt-fused portion is essential when drawing in because the locating wire of the portion and the locating wire of the portion are exposed from the coating layer. It is desirable to coat.

As a method of melting and laminating the coating layer on the pipe main body, a polyolefin resin is extruded in a tubular shape around a polyolefin resin pipe as a molded pipe main body using a crosshead die connected to an extruder. No.

Next, the conductive wire holding portion according to the present invention is obtained by a resin tube which can withstand heat during molding of the coating layer.
It is prepared with a thermoplastic resin having a higher melting point than polyolefin. Examples of such a resin include polyester and polyamide resins.

A groove-shaped holding portion parallel to the tube axis and having an outer surface side narrower than the inner surface can be manufactured by narrowing a part of the clearance of the crosshead die from the outer periphery. Because the outer surface is narrower than the inside, after the butt fusion bonding, the coated locating wire can be pushed into the groove and embedded in the coating layer before the tube is drawn in, and the locating wire can be protected. I can do it.

For fixing the conductive wire and the conductive wire holding portion, a resin tape that can withstand the heat when forming the coating layer is used.
Examples of such a resin include polyester and polyamide resins. The fixing of the conductive wire or the conductive wire holding portion to the pipe main body is not particularly limited, but can be performed in front of the crosshead die for coating and prior to coating.

The conductive wire is not particularly limited, but any wire may be used as long as it can be detected by a locator by generating a magnetic field by supplying a current to the conductive wire during repair work after embedding.
The conductive wire may be used by coating with an insulator or may be used without a coating. However, in the case of the method of embedding in the outer periphery of the coating layer, at least the coated conductive wire is preferable.

The coating of the pipe body near the butt joint part and the butt fusion part and the locating wire of the part are as follows:
The coating may be carried out using a tubular coating layer having elasticity, or after covering with a shrinkable tubular coating, it may be coated by appropriately heating and shrinking.

Thus, according to the present invention, as described in the first aspect, the pipe main body and the coating layer are peelable. This is because the scratches generated in the coating layer prevent the growth on the tube body. As described in the fourth and fifth aspects of the present invention, the locating wire can be omitted from the resin tube on which the conductive wire holding portion is formed by inserting the locating wire after the butt fusion bonding, and the joining can be omitted. The stress concentration due to the increase of the diameter accompanying the above can be avoided. Furthermore, as described in the sixth invention, the coating layer can see through the pipe main body,
The pipe buried in the third party work can be recognized by the color of the pipe body. Generally, yellow is used for gas pipes, blue for polyethylene pipes for water distribution, and orange for power / cable protection pipes. Furthermore, as described in the seventh aspect, the display tape used for fixing can be seen through, so that the recognition is further facilitated. Also, in the repair work, the material grade and thickness, which are indicated at regular intervals on the resin pipe according to the standard, can be seen through, so that troubles in the work can be avoided.

Further, as described in the eleventh invention, since the resin pipe main body is connected to another resin pipe, it is necessary to remove a coating layer which hinders fusion at the time of performing fusion. Therefore,
It is desirable from the viewpoint of the fusion work that the fusion layer is removed from the end of the resin pipe main body to be fusion-bonded in advance.

As described in the twelfth aspect, the locating wire disposed on the surface of the resin pipe is required to be connected when the resin pipe body is joined. At this time, the locating wire needs to protrude at least from the resin tube main body end to the outside, and more preferably protrudes by 10 cm or more.

As described in the thirteenth invention, since the end of the resin tube main body is connected to another resin tube, it is necessary to remove a coating layer which hinders the fusion at the time of performing the fusion. Therefore, a structure in which the thickness of the coating layer is extremely thinner in the circumferential direction and in the tube length direction than the other coating layer portions so that the coating layer is easily peeled off in advance from the coating layer at the end of the resin pipe main body to be fusion-bonded, an example. As FIG.
It is desirable that a notch as shown in FIG.

The resin pipe of the present invention is applicable to both straight pipes (for example, short pipes of 5 m and 5.5 m in length) and coiled pipes (for example, long pipes of 30 to 90 m in length). The length of the resin tube is not limited.

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. (Example 1) Preformed polyethylene pipe for water distribution (1)
A 0.5 mm diameter copper wire is coated with polyethylene on the outer surface of the nominal diameter 75, and a conductive wire (3) having an outer diameter of 2 mm is coated at intervals of 60 cm in the tube axis direction with a PVC tape having an adhesive layer. The resin tube was fixed using (6) and extruded and coated with a polypropylene resin (2) to a thickness of 2 mm with a crosshead die to produce a resin tube. 2 schematically shows the resin tube of FIG. 1.

Example 2 A polyethylene pipe for gas extruded in front of a crosshead die (1) Nominal diameter 15
A polyamide tube (2) having an outer diameter of 4.5 mm and a thickness of 0.8 mm was fixed and coated on the outer surface of Sample No. 0 in the same manner as in Example 1 to produce a resin tube. FIG. 2 schematically shows the resin tube. In addition,
In the figure, reference numeral 4 denotes a conductive wire holding portion, and 6 denotes a fixing tape.

Example 3 A polyethylene pipe for gas extruded in front of a crosshead die (1) Nominal diameter 150
On the outer surface of the resin tube, a projection is provided on a part of the mouthpiece of the crosshead die extruder, and a polypropylene resin is extruded. A resin tube having a thickness of 2.5 mm and a depth of 2 mm on the outer circumferential side (groove 5) is provided. (2) was produced. FIG. 3 schematically shows the resin tube.

(Example 4) After the tube of Example 3 was subjected to butt fusion bonding, the portion and the vicinity thereof were covered with a heat-shrinkable tube made of crosslinked polyethylene having an outer diameter of 200 mm and a thickness of 2 mm.

(Embodiment 5) In FIG. 5, four notches 7a along the longitudinal direction of the coating layer 2 are formed at regular intervals in the circumferential direction, and notches 7b are further formed in the circumferential direction.

[0048]

As described above, since the resin pipe according to the present invention is constructed as described above, it can be used not only for the method of cutting the buried portion but also for the non-cutting method.
It is difficult to make sharp scratches on the pipe body. In addition, since the coating layer can be peeled off from the pipe main body, scratches on the coating layer do not affect the pipe main body. Thus, regardless of the construction method, it is possible to avoid the influence of the damage due to the soil at the time of backfilling, and it is not necessary to consider the soil, so that it is possible to return to the original soil, leading to a reduction in the construction cost. Further, the piping method covering the butt fusion joint is useful for protecting the pipe body and the locating wire, and can prevent disconnection of the locating wire.
Therefore, it is very useful as a resin pipe for water distribution and gas.

Further, the type of the tube main body can be easily recognized by the transparent coating layer. Further, by using a polyolefin resin as the coating layer, the processing after moating can be facilitated.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a resin tube of the present invention.

FIG. 2 is a diagram showing another embodiment of the present invention.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is an enlarged view of a part of FIG. 3;

FIG. 5 is a diagram showing still another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... resin pipe main body, 2 ... coating layer, 3 ... conductive wire (locating wire), 4 ... conductive wire holding part, 5 ... groove, 6 ... fixing tape 7a , 7b ... notch

Continued on the front page (72) Inventor Yuji Fukushima 6-16-3-901 Oshima, Koto-ku, Tokyo (72) Inventor Nozomi No. 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (72) Inventor Sachi Kitao, 1-2-1, Marunouchi, Chiyoda-ku, Tokyo, Japan Nihon Kokan Co., Ltd. (72) Inventor Takayuki Kato 1-1-2, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan F-term 3H024 EA02 EC10 ED04 EE06 3H111 AA02 BA15 CB03 CB14 CB23 CB29 DA03 DA26 DB03 DB05 DB17 EA04

Claims (14)

[Claims] 1. A resin pipe main body, a conductive wire disposed along the axial direction of the resin pipe main body, and melt-laminated so as to be peelable by extrusion on the outer periphery of the resin pipe main body. A resin tube for burying a pipe, comprising: a coating layer for protecting a conductive wire. 2. A resin pipe main body, a conductive wire disposed and fixed on an outer peripheral surface of the resin pipe main body along the axial direction thereof, and a coating layer melt-laminated by extrusion molding on the outer circumference of the resin pipe main body. The resin pipe for burying a pipe according to claim 1, which is formed. 3. A resin pipe main body, a conductive wire holding portion disposed and fixed along an axial direction of the resin pipe main body, a conductive wire housed in the holding portion, and an outer periphery of the resin pipe main body. The resin pipe for burying pipes according to claim 1, further comprising: a coating layer melt-stacked by extrusion molding. 4. A groove-shaped conductive wire holding portion parallel to the tube axis of the resin pipe main body is formed on the outer surface of the coating layer, and the groove-shaped conductive wire holding portion has an opening on the outer surface of the coating layer from the inside. The resin pipe for burying a pipe according to claim 1, which is narrowed. 5. The resin pipe for burying a pipe according to claim 1, wherein an elongated conductive wire holding portion parallel to the pipe axis of the resin pipe main body is formed inside the coating layer. 6. The resin pipe according to claim 1, wherein the coating layer is formed of a material through which the pipe body can be seen. 7. The resin pipe according to claim 1, wherein the conductive wire and / or the conductive wire holding portion is fixed with a tape. 8. The resin pipe according to claim 1, wherein the resin pipe body is a polyolefin resin. 9. The resin pipe for embedding piping according to claim 1, wherein the coating layer is a polyolefin resin of a material different from that of the resin pipe main body. 10. The resin pipe according to claim 1, wherein the resin layer has a thickness exceeding 1.5 mm. 11. The resin pipe for burying a pipe according to claim 1, further comprising an exposed portion that is not covered at an end of the resin pipe main body. 12. The resin pipe for burying a pipe according to claim 1, wherein the conductive wire disposed on the resin body protrudes from an end of the resin pipe body. 13. The resin tube for burying a pipe according to claim 1, wherein an easy-peeling portion is provided in advance in the coating layer over an end portion and / or the entire length of the resin tube main body. 14. The connecting portion is protected by peeling off a covering portion near the connecting portion and fusing and joining using a butt fusion or joint, and then covering the connecting portion with a covering member. The method for constructing resin pipes for burying pipes according to the above.