KR20080057794A - Foaming sheet for connecting underground pipes and method for making the foaming sheet - Google Patents

Abstract

A foaming sheet for connecting underground pipes and a method for making the foaming sheet are provided to uniformly foam a sheet with respect to the entire circumference of two pipes. Underground pipes(10,10') are arranged such that end portions of the underground pipes are connected to each other. A foaming sheet(12) is wounded around adjacent end portions of the pipes. The end portions of the pipes are fixed by using a fixture band(16) and then the foaming sheet is foamed. The foaming sheet includes a wrapped wire buried in a zig-zag way. The foaming sheet includes a first sheet material and a second sheet material. A heating wire panel is interposed between the first and second sheet materials.

Description

Foam sheet for underground buried pipe and manufacturing method {FOAMING SHEET FOR CONNECTING UNDERGROUND PIPES AND METHOD FOR MAKING THE FOAMING SHEET}

1 is a cross-sectional view showing a state in which two pipes constituting the underground buried pipe using the foam sheet and the fixing band of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1. FIG.

Figure 3 is a perspective view of the foam sheet of the present invention.

4 is a partial cross-sectional view.

5 is a plan view showing a heating element sheet structure used in the present invention.

6 is a partially enlarged plan view of the heating element sheet structure shown in FIG.

7 is an explanatory diagram showing a process of manufacturing the foam sheet of the present invention.

FIG. 8 is a diagram illustrating a modification of the heating wire sheet structures and showing a structure for preventing the heating wires from being concentrated at overlapping portions when they are cut and used. FIG.

Explanation of Signs of Major Parts of Drawings

10, 10 '... pipe 12 ... foam sheet

16 ... fixed band 18 ... sheathed heating wire

20 ... Heating panel 22, 24 ... Sheet material

26 ... bevel 28, 30 ... roll

The present invention relates to a foam sheet for connecting underground buried pipe, and in particular, each section of the heating wire embedded in the foam sheet in a zigzag shape is wound around the end of the two pipes constituting the underground pipe by maintaining a constant distance. It relates to a foam sheet for underground buried pipe connecting the foam sheet is uniformly foamed and fused through the entire peripheral edge.

Conventionally, in the periphery of the connecting end of the two pipes to be connected in order to connect the connecting ends of the two underground pipes without leakage, a fusion sheet in which the heating wires are arranged in a zigzag form is wound on the inner surface side and restrained to the connecting end of the pipe The fixing band was fastened. As such, the fusion sheet constrained by the fixing band with respect to the connection end of the pipe is applied with a voltage to the heating wire disposed on the inner surface thereof so that the connection surface between the pipe and the fusion sheet to be connected by heat generation is heat-sealed.

However, it is very difficult to arrange the heating wires in a zigzag form on the inner surface of the fusion sheet in contact with the main surface of the connecting end of the two pipes, and the spacing between the sections of the heating wires arranged in such a zigzag form cannot be kept constant. There was a defect that the thermal fusion between the end face and the fusion sheet became uneven.

In addition, the applicant's registration Utility Model Publication No. 20-01402687 discloses that the foam sheet is heated and foamed while the foam sheet is constrained by the support sheet by winding the foam sheet and the support sheet superimposed on the outer surfaces of the connection ends of the two pipes to be connected. The undergrounding pipe connecting device is introduced to securely seal the connecting end of the pipe. In the prior art, a heating wire is embedded in the foam sheet, and when a voltage is applied thereto, the heating wire generates heat to melt and foam the foam sheet, and the support sheet has a function of supporting the foam sheet. However, this prior art also has a drawback in that the spacing of the sections of the heating wire cannot be kept constant when the heating wire is arranged in a zigzag form in the foam sheet.

In the present invention, in view of such a conventional point, the two pipes constituting the underground buried pipe by making the heating wire arranged in a zigzag form in the foam sheet so that the interval between each section portion of the heating wire can be kept constant. It is an object of the present invention to provide a foam sheet for underground buried pipe connection in which the foam sheet wound around the end edge of the foam sheet can be uniformly foamed and fused through the entire peripheral edge.

Still another object of the present invention is to provide a manufacturing method capable of continuously manufacturing such a foam sheet for underground buried pipe connection.

To this end, in the present invention, at least once around the adjacent end portions of the two pipes constituting the underground buried pipe and fixed by fastening to the end portion of the pipe with a fixing band fastened by a bolt-nut assembly to be connected by foaming Foam seat for connecting underground buried pipes to be fusion-fixed to the connecting ends of two pipes, wherein the foam seat is provided with a foam seat for connecting underground buried pipes comprising a sheet material in which coated heating wires are arranged in a zigzag form. do. According to the present invention, each of the coated heating wires constituting the weft yarn by knitting by inserting the coated heating wires in the process of forming a plurality of warp yarns into the chain knitting tissue and weaving them at regular intervals into the warp loops formed into the chain knitting tissue. It is characterized in that the section portion is composed of the heating wire panels arranged to be spaced at regular intervals and disposed between the sheet materials.

In this invention, the material of the sheet is a metallocene polyethylene mixed with 0.5 to 1.5% by weight of azodicarbonamide as a blowing agent, and the slope is polyethylene similar to the main constituent of the sheet material.

In addition, the present invention can be fused and fixed to the connecting end of the two pipes to be connected by foaming after winding at least once around the adjacent end portion of the two pipes constituting the underground pipe and fixed to the end portion of the pipe with a fixing band In order to provide a method for manufacturing a foam sheet for underground buried pipe connection consisting of a sheet material arranged in a zig-zag form so that the coated heating wire therein. This method of the present invention comprises the steps of preparing a first sheet material in the form of a roll by mixing the metallocene polyethylene as a main material with 0.5 to 1.5% by weight of azodicarbonamide as a blowing agent and low-temperature extrusion into a sheet by an extruder, In the process of forming a large number of slopes of polyethylene material into the chain piece structure, the coated heating wire is fed into the weft yarn and inserted at regular intervals into the inclined loops, so that each section of the coated heating wire is arranged at regular intervals in the form of a roll. The step of preparing, supplying the continuous first sheet material and the continuous heating wire panel each prepared in the form of a roll in the form that the heating wire panel is superimposed on the first sheet material, and the heating wire panel is superimposed on the first sheet material 0.5-1.5% by weight of azodicarbon flax as a blowing agent to the metallocene polyethylene on the heating panel Degas by low temperature extrusion of the foam of the resin solution of a mixed composition layer and the second sheet material is characterized by consisting of a copolymer comprising: a foamed sheet.

Referring to the present invention in more detail based on the accompanying drawings as follows.

1 and 2 illustrate a structure in which two pipes 10 and 10 'are connected by using a foam sheet for underground buried pipe connection of the present invention. These two pipes 10, 10 'constitute the underground burial pipe.

As such, the two pipes 10 and 10 'constituting the underground burial pipe are arranged to excavate the buried trench at the place to be buried, and then arrange the pipes 10 and 10' having a predetermined length so that the end to the end face each other. The end portions of the pipes 10, 10 'are then secured with a fixing band 16 which is wound around the end portions of these pipes 10, 10' with the foam sheet 12 and fastened to the bolt-nut assemblies 14. After fastening with respect to the foam sheet 12 is foamed so that it can be fused and fixed to the connecting end of the two pipes (10) (10 ') to be connected.

The foam sheet 12 used for such underground buried pipe connection is configured as follows according to the present invention.

As shown in FIG. 3, the foam sheet 12 of the present invention has a structure in which the coated heating wire 18 is embedded in a zigzag form.

The covered heating wire 18 is embedded in the form of a heating wire panel 20, as will be described in detail later.

The foam sheet 12 is composed of a first sheet material 22 and a second sheet material 24, and the heating wire panel 20 is interposed between the first sheet material 22 and the second sheet material 24. .

The first sheet material 22 and the second sheet material 24 are made of metallocene PE (polyethylene), and 0.5 to 1.5% by weight of azodicarbonamide is mixed as a foaming agent, and then extruded at a low temperature of 1 to 3 mm. It consists of a sheet form of thickness.

On the other hand, the heating wire panel 20, as shown in Figures 5 and 6 is a plurality of warp 26 is formed into a chain stitch (chain stitch) in the process of knitting the coated heating wire (18) in the weft and is knitted into a chain knitting structure By inserting and knitting at regular intervals in the loop of the warp 26, each section portion of the coated heating wire 18 constituting the weft yarn is arranged at regular intervals. The warp 26 of this heating panel 20 is made of polyethylene similar to the material of the first and second sheet materials 22, 24 mentioned above, for example. The coated heating wire 18 has a property of generating heat when a power source is connected and is coated for insulation.

Such a heating wire panel 20 is embedded between the first sheet material 22 and the second sheet material 24 to manufacture the foam sheet 12 of the present invention will be described as follows with reference to FIG.

First, the first sheet material 22 is prepared. As mentioned above, the first sheet material 22 is mixed with metallocene PE as a main material and 0.5 to 1.5% by weight of azodicarbonamide as a blowing agent, and is extruded at low temperature with an extruder to form a sheet of 1 to 3 mm thickness. Is prepared. Such a first sheet material 22 may be prepared in the form of a roll 28.

Next, the heating wire panel 20 is prepared. As mentioned above, in the process of forming a large number of warp yarns 26 made of polyethylene, the coated heat transfer wire 18 is spun into the weft yarn and inserted into the loop of the warp 26 at regular intervals. Each section portion has a structure arranged at regular intervals. Such a heating panel 20 may also be prepared in the form of a roll (30).

As described above, the continuous first sheet material 22 and the continuous heating wire panel 20 prepared in the form of the rolls 28 and 30 are respectively formed on the first sheet material 22 on the flat support 32. 20 is supplied in an overlapping form. In the process of supplying the heating panel 20 overlapping the heating sheet 20 on the first sheet material 22, the foam having a composition in which 0.5 to 1.5% by weight of azodicarbonamide is mixed as the blowing agent to the metallocene PE on the heating panel. The resin liquid is extruded from the extruder 34 at low temperature so that the second sheet material 24 is laminated. As described above, the second sheet member 24 laminated on the heating panel 20 overlapped with the first sheet member 22 has a thickness of about 1 to 3 mm and the first sheet member 22 and the heating panel 20. When the foam sheet 12 is formed by being incorporated and cured, the total thickness thereof is about 3 to 7 mm.

The foam sheet 12, which is continuously manufactured in this manner, is cut and used to a suitable length capable of winding one or more connecting ends of the two pipes 10, 10 'constituting the underground buried pipe. The foam sheet 12 cut to an appropriate length can be used as a terminal for feeding power by drawing the end of the coated insulating wire 18 on both end sides.

Such a foam sheet for buried underground pipe connection of the present invention is foamed at least once around the adjacent end portion of the two pipes (10) (10 ') constituting the underground buried pipe as shown in FIG. The sheet 12 was wound and the fixing band 16 was placed on the foam sheet 12, and then tightened with the bolt-nut assembly 14 to press the foam sheet 12 against the pipes 10 and 10 '. In the state, a voltage is applied to the end of the coated heating wire 18 drawn out from the end of the foam sheet 12. When a voltage is applied to the coated heating wire 18, the heating wire panel 20 in which the coated heating wire is arranged in a zigzag form is uniformly generated by the resistance heat, and the sheet material incorporated in both sides of the heating wire panel 20 by such heating. (22) (24) are melt-foamed and filled with the melt expanding in the limited space between the two pipes (10) (10 ') and the fixed band (16), so that after cooling the end portions of the pipes (10) (10') And the fixing band 16 can be completely sealed. In this way, when the coated heating wire 18 generates resistance heat by application of voltage, the heating wire panel 20 constituted by the coated heating wire 18 maintains the interval between the sections of the coated heating wire 18 arranged in a zigzag form. The inclined 26 to maintain the interval between the sections of the coated heating wire 18 so that the generated heat can be generated in a uniform distribution, while the material of the inclined 26 in the final melting step It is made of the same polyethylene as the main constituents of the ashes 22 and 24 and can be melted integrally upon the melt foaming of the foam sheet 12.

8 is a view showing the deformation of the heating wire sheet structure, when they are used to cut the heating wire in the cut portion to eliminate the possibility of partial overheating may occur by concentrating the heating wire in the overlapping portion when placed around the pipe The structure of the gap is wider than the other parts.

As described above, the present invention allows the heating sheet arranged in a zigzag form in the foam sheet to maintain a constant interval between the sections of the heating coil so that the foam sheet wound around the end of the two pipes constituting the underground buried pipe is transferred. Provided is a foam sheet for underground buried pipe connection to be uniformly foamed and fused through the periphery.

Claims (3)

The pipe (10) (10) with a fixing band (16) wound at least once around the adjacent end portions of the two pipes (10) (10 ') constituting the underground pipe and fastened by bolt-nut assemblies (14). A foam sheet for underground buried pipe connection, which is fused and secured to a connection end of the two pipes 10, 10 'to be connected by foaming after being fixed to an end portion of'), wherein the foam sheet ( 12, which is composed of sheet members 22 and 24 in which the coated heating wires 18 are arranged in a zigzag form, wherein the coated heating wires 18 have a plurality of warp yarns 26 knitted into a chain piece structure. Each section portion of the coated heating wire 18 constituting the weft yarn is formed by weaving by inserting the coated heating wire 18 as a weft yarn and inserting it at regular intervals in a loop of the warp 26 knitted into a chain knitting structure. With heating wire panel 20 to be placed It consists of the foamed sheet for Buried pipe connection, characterized by disposed between the sheet material 22, 24. The material of the sheets 22 and 24 is metallocene polyethylene mixed with 0.5 to 1.5% by weight of azodicarbonamide as a blowing agent, and the inclined 26 is a sheet material 22 ( Foam sheet for underground buried pipe connection, characterized by polyethylene similar to the main constituent of 24). At least one time is wound around the adjacent end portions of the two pipes 10, 10 'constituting the underground pipe and fastened to the end portions of the pipes 10, 10' with a fixing band 16. Underground buried consisting of sheet materials 22 and 24 in which the coated heating wires 18 are arranged in a zigzag form so as to be fused and fixed to the connection ends of the two pipes 10 and 10 'to be foamed and connected. In the method for producing the foamed sheet 12 for pipe connection, this method is mixed with metallocene polyethylene as a main material and 0.5 to 1.5% by weight of azodicarbonamide as a foaming agent, and is extruded at low temperature onto a sheet by an extruder to form a roll ( Preparing the first sheet material 22 in the form of 28, in the process of forming a large number of warp 26 made of polyethylene material into a chain piece structure, the coated heating wire 18 is fed to the weft yarn and the warp 26 Are inserted at regular intervals in the loop of Preparing a heating wire panel 20 in the form of a roll 30, wherein each section portion of the coated heating wire 18 is arranged at regular intervals, the continuous of the prepared in the form of each of the rolls 28, 30 Supplying the first sheet member 22 and the heating element panel 20 continuous to the first sheet member 22 in such a manner that the heating element panel 20 overlaps the first sheet member 22, and the first sheet member 22; In the process of supplying the heating panel 20 in the form of overlapping), the foamed resin having a composition of 0.5 to 1.5% by weight of azodicarbonamide as a blowing agent on the metallocene polyethylene on the heating panel 20 The method of manufacturing a foam sheet for underground buried pipe connection, comprising the step of low-temperature extrusion of the liquid and forming the second sheet material (24) to form a coalescing into the foam sheet (12).

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