JP2012251636A - Flexible pipe for gas transportation, and method for improving external damage resistance thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pipe for gas transportation which is resistant to external damage from the outside even if the pipe is made of resin.SOLUTION: The gas pipe 1 mainly includes a pipe body 3, a reinforced layer 5, a buffer layer 7, an outer pipe 9, and the like. The pipe body 3 is positioned in the innermost later of the gas pipe 1. The pipe body 3 is made of resin, for example, polyethylene (high-density polyethylene). The reinforced layer 5 is provided on the outer periphery of the pipe body 3. The reinforced layer 5 is a reinforced layer against an internal pressure of gas flowing through the pipe body 3. The pipe body 3 wound with the reinforced layer 5 is formed as a composite pipe 6. The buffer layer 7 is provided on the outer periphery of the composite pipe 6. The buffer layer 7, which is an elastic member with elasticity, can use a resin foam such as polyurethane and crosslinked foamed polyethylene. The outer pipe 9 is provided on the outer periphery of the buffer layer 7.

Description

  The present invention relates to a flexible tube for gas transportation for transporting a gas such as natural gas.

  Usually, a steel pipe is used for piping for transporting a gas such as natural gas. As long as the steel pipe has pressure resistance, it can be applied regardless of the pressure of the gas used.

  Here, the gas pressure is determined according to the gas business method as low pressure (water column gauge pressure less than 0.1 MPa), medium pressure B (water column gauge pressure 0.1 MPa to less than 0.3 MPa), medium pressure A (water column gauge pressure 0. 3 MPa to less than 1.0 MPa) and high pressure (water column gauge pressure of 1 MPa or more).

  Further, according to JIS K6774, it is stipulated that a polyethylene base pipe (PE80) can be used as a gas pipe for low pressure to medium pressure B applications. For example, Patent Document 1 describes that a polyethylene pipe or a metal flexible pipe can be used as a gas pipe drawn into the primary side of a gas meter in a site. (Patent Document 1).

JP 2006-194349 A

  By the way, normally, piping for gas transportation is buried and laid in the ground. However, not only gas pipes but also water, electricity and other pipes are buried in the normal ground. Each such piping may be dug as needed. However, for example, when excavating other piping, a heavy machine for ground excavation may accidentally contact the gas piping.

  In such a case, if the steel pipe is conventionally used, the piping will not be easily deformed or damaged, and the internal gas will not leak out, but if a resin pipe is used, it will contact the heavy machinery. May damage the piping.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a gas transportation pipe that is not easily damaged from the outside even if a resin pipe is used.

  In order to achieve the above-described object, the first invention provides a resin outer tube on the outer periphery of a composite tube comprising a flexible resin tube and a reinforcing layer provided on the outer periphery of the tube. When a tube is provided, a buffer layer is provided between the outer surface of the composite tube and the inner surface of the outer tube, the outer tube is deformed or damaged, and an external force is applied in the center direction of the composite tube, The flexible tube for gas transport, wherein the outer surface of the composite tube can be prevented from being damaged by the collapse of the buffer layer.

  The buffer layer may be formed of a resin foam. A metal tape may be further wound around the inner layer side of the reinforcing layer. A resin protective layer may be further formed on the outer periphery of the reinforcing layer of the composite pipe. A nylon layer may be further provided on at least one of the inner layer side and the outer layer side of the protective layer.

  According to the first invention, since the buffer layer is provided between the outer tube and the composite tube, the buffer layer is crushed by the earth pressure because, for example, the outer tube is subjected to earth pressure even in a state where it is buried in the ground. It will not be. Even when an external force is applied from the outside by a heavy machine or the like, the influence of the external force on the composite tube can be reduced by the buffer layer.

  That is, when the outer pipe is deformed or damaged by a heavy machine or the like and an external force is applied from above to the lower side of the composite pipe through the buffer material, the outer surface of the composite pipe is formed by the buffer material between the heavy machine and the composite pipe. The force applied to the composite pipe is reduced and the cushioning material on the lower side of the composite pipe is crushed, so that the composite pipe is bent downward and the force applied to the outer surface of the composite pipe can be reduced. Therefore, damage to the outer surface of the composite pipe can be prevented.

  Even when such a buffer layer is formed, the outer tube is used, so that even if rolling is performed after being buried in the ground, the buffer layer is not crushed and the ground is reliably rolled. be able to. As such a buffer layer, a resin foam is applicable as a buffer material.

  Moreover, wound resistance can be further improved by forming a metal layer by winding a metal tape around the inner layer side of the reinforcing layer. In addition, the metal layer can function as a gas barrier layer that prevents internal gas from leaking out of the tube.

  In addition, by forming a protective layer on the outer periphery of the composite pipe, the reinforcing layer and the like are not damaged during pipe laying work or transportation. Further, by forming a nylon layer, it is possible to prevent the inside of the composite tube from being damaged when contacting heavy machinery or the like.

  According to a second aspect of the present invention, a buffer material is provided on the outer periphery of a composite tube including a flexible resin tube and a reinforcing layer provided on the outer periphery of the tube, and the buffer material is provided. The composite pipe is inserted into a resin outer pipe and buried in the ground, and the outer pipe receives a force against earth pressure from the ground, and the outer pipe is deformed or damaged when excavating the ground. When the external force is applied in the central direction of the composite pipe through the buffer material, the force applied to the outer surface of the composite pipe by the buffer material on the upper side of the composite pipe is reduced, and the composite pipe Damage to the flexible tube for transporting gas, wherein the composite tube itself is bent downward and the force applied to the outer surface of the composite tube is reduced when the cushioning material on the lower side is crushed It is an improvement method.

  According to the second aspect, since the buffer layer is provided between the outer tube and the composite tube, the buffer layer is not crushed by earth pressure even in a state where it is buried in the ground. Even when an external force is applied from the outside by a heavy machine or the like, the influence of the external force on the composite tube can be reduced by the buffer layer.

  ADVANTAGE OF THE INVENTION According to this invention, even if it uses resin piping, the piping for gas transport etc. which are hard to receive the damage from the outside can be provided.

It is a figure which shows the piping 1 for gas, (a) is a perspective view, (b) is sectional drawing. The longitudinal cross-sectional view which shows the state by which the piping 1 for gas was embed | buried under the ground. The figure which shows the state which the heavy machinery 13 contacts the piping 1 for gas. It is a figure which shows the piping 20 for gas, (a) is a perspective view, (b) is sectional drawing. It is a figure which shows the piping 30a for gas, (a) is a perspective view, (b) is sectional drawing. It is a figure which shows the piping 30b for gas, (a) is a perspective view, (b) is sectional drawing. It is a figure which shows the piping 40 for gas, (a) is a perspective view, (b) is sectional drawing.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a view showing a gas pipe 1, FIG. 1 (a) is a perspective view, and FIG. 1 (b) is a cross-sectional view. A gas pipe 1 which is a flexible pipe for gas transportation is mainly composed of a pipe body 3, a reinforcing layer 5, a buffer layer 7, an outer pipe 9, and the like. The gas pipe 1 is a flexible pipe used for transporting natural gas or the like.

  The pipe body 3 is located in the innermost layer of the gas pipe 1. The tube body 3 is made of resin, for example, made of polyethylene (high density polyethylene). The tube body 3 is excellent in flexibility, and a gas flows inside.

  A reinforcing layer 5 is provided on the outer periphery of the tube body 3. The outer periphery of the tube body 3 means outside the tube body 3 in a cross section unless otherwise specified, and may have another layer structure between the tube body 3 and the reinforcing layer 5. Is included. In the following description, in the positional relationship of each layer, it is simply referred to as “periphery”, but it is needless to say that similarly, those having other layer structures between the respective layers are included.

  The reinforcing layer 5 is a reinforcing layer against the internal pressure of the gas flowing in the tube body 3. Therefore, the pressure resistance strength of the reinforcing layer 5 is set according to the internal pressure used. The reinforcing layer 5 is formed, for example, by winding a fiber reinforcing tape. The pipe body 3 around which the reinforcing layer 5 is wound is referred to as a composite pipe 6.

  A buffer layer 7 is provided on the outer periphery of the composite tube 6. The buffer layer 7 is an elastic member having elasticity, and for example, a resin foam such as polyurethane or crosslinked foamed polyethylene can be used.

  An outer tube 9 is provided on the outer periphery of the buffer layer 7. The outer tube 9 is made of resin, for example, made of polyethylene. The outer tube 9 is preferably a corrugated tube (not shown). Further, the composite pipe 6 is preferably arranged at the approximate center of the outer pipe 9. As described above, the gas pipe 1 includes the pipe body 3, the reinforcing layer 5, the buffer layer 7, and the outer pipe 9 in order from the inside.

  For example, the gas pipe 1 has a reinforcing layer 5 in which a reinforcing tape having a thickness of 1 mm and a width of 100 mm is wound around the outer periphery of a high-density polyethylene tube 3 having an outer diameter of 180φ and a thickness of 13.3 mm. A formed buffer layer 7 made of a resin foam having a thickness of 30 mm and an outer tube 9 made of polyethylene having an outer diameter of 250 and a thickness of 3 mm can be used.

  Next, a method for manufacturing the gas pipe 1 will be described. A fiber reinforced tape is supplied to the outer periphery of the tube 3 from a fiber reinforced tape feeder or the like with respect to the resin tube 3 manufactured by extrusion in advance. The fiber reinforced tape is spirally wound around the outer periphery of the tube body 3 so that the end portion wraps in the axial direction of the tube body 3. Here, it is preferable that the fiber reinforced tape is wound in a double spiral in the same direction or wound in a spiral in the forward and reverse directions.

  A resin foam is provided on the outer periphery of the tube body 3 (composite tube 6) on which the reinforcing layer 5 is provided. The resin foam is a pipe body that is vertically cut, and may be put on the outer periphery of the composite pipe 6 with the cut open, and a resin foam provided in half on the outer periphery of the composite pipe 6 may be used. The composite tube 6 may be inserted through a tubular resin foam. Further, the composite pipe 6 covered with the resin foam is inserted through an outer pipe formed by extrusion in advance. Thus, the gas pipe 1 is manufactured. In addition to the above, a resin foam sheet may be wound around the outer periphery of the composite tube by multiple turns. The number of spiral windings can be appropriately determined depending on the thickness of the resin foam sheet and the required thickness of the buffer layer. For example, the thickness of the resin foam sheet is 5 to 10 mm, and it is desirable to perform spiral winding at least twice, preferably 3 to 4 times. The sheet is wound preferably by aligning the end faces of the sheets and spirally winding so that adjacent sheets do not overlap, but may be spirally wound by wrapping that partially overlaps the sheet end portions. Further, cross winding may be performed in which a plurality of upper and lower layers are alternately wound in opposite directions.

  Next, the function of the gas pipe 1 will be described. FIG. 2 is a schematic cross-sectional view showing a state where the gas pipe 1 is embedded. As shown in FIG. 2, a buffer layer 7 is formed inside the gas pipe 1. The buffer layer 7 is a flexible material. However, since the outer tube 9 is provided on the outermost periphery, even if earth pressure in a state of being buried in the ground is applied to the gas pipe 1, the internal buffer layer 7 is not crushed. In addition, when the ground 11 is rolled, even if a force is applied from the top of the ground 11 (in the direction of arrow A in the figure), the buffer layer 7 is covered with the outer tube 9, so that the ground 11 can be firmly solidified. it can.

  Here, as shown in FIG. 3A, the ground may be excavated from the ground in a state where the gas pipe 1 is buried in the ground. For example, it is a case where another pipe or the like is buried in the vicinity of the position where the gas pipe 1 is buried, or a case where the gas pipe 1 is exchanged or confirmed. At this time, there is a possibility that the excavating heavy machine 13 (for example, excavator) may come into contact with the gas pipe 1 by mistake.

  Even in this case, as shown in FIG. 3A, the outer tube 9 itself functions as a protective layer for preventing damage to the inner tube body 3. That is, the inner tube 3 can be protected by the outer tube 9.

  Further, as shown in FIG. 3B, even when the outer pipe 9 is deformed or damaged and an external force is applied from the outer surface of the gas pipe 1 by the heavy machine 13 (pressed by the heavy machine 13), the heavy machine 13 and the outer surface of the tube body 3 (above the tube body 3 and B portion in the figure) serve as a cushion to prevent the heavy machinery 13 from directly contacting the tube body 3 (composite tube 6). At the same time, the buffer layer 7 on the side opposite to the heavy machine 13 (below the tube 3 and part C in the figure) is crushed, so that the composite pipe 6 escapes from the heavy machine 13 so that it bends downward. It is possible to prevent the heavy machine 13 from coming into contact with the composite pipe 6.

  As described above, according to the gas pipe 1 according to the first embodiment, since the buffer layer 7 is provided, the composite pipe 6 inside is protected even if the heavy machine 13 or the like contacts the gas pipe 1. can do. Therefore, even when the heavy machine 13 accidentally contacts the gas pipe 1, the composite pipe 6 is not damaged, and the internal gas can be prevented from leaking.

  In addition, by providing the outer tube 9, the inner composite tube 6 can be more reliably protected, and even if the flexible buffer layer 7 is provided, the gas pipe 1 is protected against earth pressure from the outer periphery. The buffer layer 7 is not crushed when the ground is further crushed, and the ground cannot be crushed.

  Next, a second embodiment will be described. In the following embodiment, components having the same functions as those shown in FIG. 1 are given the same reference numerals as those in FIG. 1 to avoid redundant description.

  FIGS. 4A and 4B are views showing the gas pipe 20 used in the second embodiment. FIG. 4A is a perspective view and FIG. 4B is a cross-sectional view. The gas pipe 20 has substantially the same configuration as the gas pipe 1, but differs in that a protective layer 21 is provided.

  The protective layer 21 is a layer for preventing the reinforcing layer 5 from being damaged at the time of laying or handling, and for preventing the reinforcing layer 5 and the like from being irradiated with ultraviolet rays. The protective layer 21 is made of, for example, low density polyethylene. The protective layer 21 may be formed by extruding a resin on the outer periphery in a state where the reinforcing tape is wound around the outer periphery of the tubular body 3 as described above.

  According to the gas pipe 20 according to the second embodiment, the same effect as the gas pipe 1 can be obtained. Moreover, since the protective layer 21 is formed in the outer periphery of the reinforcement layer 5, it can prevent that the reinforcement layer 5 is damaged at the time of handling. Further, the reinforcing tape does not peel off or shift during handling. Further, the protective layer 21 can prevent the reinforcing layer 5 from being damaged when the heavy machinery 13 or the like comes into contact.

  Next, a third embodiment will be described. FIGS. 5A and 5B are views showing a gas pipe 30a used in the third embodiment. FIG. 5A is a perspective view and FIG. 5B is a cross-sectional view. The gas pipe 30 a has substantially the same configuration as the gas pipe 20, but differs in that a nylon layer 31 is further provided on the outer periphery of the protective layer 21.

  The nylon layer 31 may be about 0.5 mm, for example. The nylon layer 31 is formed by extrusion-coating nylon on the outer periphery of the protective layer 21. The nylon layer 31 has a high hardness. For this reason, when a heavy machine etc. contact, the surface will not be easily removed. Therefore, it is possible to prevent heavy machinery from coming into contact with the reinforcing layer 5 inside the nylon layer 31. That is, by providing the nylon layer 31, higher damage resistance can be obtained.

  A gas pipe 30b as shown in FIG. 6 may be used. 6A is a perspective view of the gas pipe 30b, and FIG. 6B is a cross-sectional view. The nylon layer 31 may be formed not on the outer peripheral side of the protective layer 21 but on the inner peripheral side. Even in this way, the nylon layer 31 can prevent damage to the internal composite pipe (the reinforcing layer 5).

  Although the entire protective layer 21 in the gas pipe 20 can be made of nylon, the expensive nylon layer becomes thick. For this reason, it is desirable to form a nylon layer 31 thinner than the protective layer 21 on the inner peripheral side or the outer peripheral side of the protective layer 21.

  According to the gas pipes 30a and 30b according to the third embodiment, the same effect as that of the gas pipe 1 can be obtained. Moreover, since the nylon layer 31 with high trauma resistance is formed on the outer periphery of the reinforcing layer 5, it is possible to more reliably prevent the internal layers from being damaged.

  Next, a fourth embodiment will be described. 7A and 7B are views showing a gas pipe 40 used in the fourth embodiment. FIG. 7A is a perspective view and FIG. 7B is a cross-sectional view. The gas pipe 40 has substantially the same configuration as the gas pipe 1, but differs in that a metal layer 41 is further provided on the inner peripheral side of the reinforcing layer 5.

  The metal layer 41 enhances the damage resistance due to the reinforcing layer 7. That is, when the heavy machinery comes into contact with the gas pipe 40, the inner tube body is prevented from being damaged by the reinforcing layer 5, but by forming the metal layer 41 inside the reinforcing layer 5, it is more reliable. Damage to the tube body 3 can be prevented.

  The metal layer 41 is configured by winding a metal tape made of stainless steel, aluminum or the like around the outer periphery of the tube body 3 without a gap. The winding method of the metal tape may be spiral winding or vertical side winding. The metal tape and the tube 3 may be bonded with an adhesive or the like.

  According to the gas pipe 40 according to the fourth embodiment, the same effect as the gas pipe 1 can be obtained. Moreover, since the metal layer 41 with high trauma resistance is formed on the inner periphery of the reinforcing layer 5, it is possible to more reliably prevent the tubular body 3 from being damaged.

  Further, the metal layer 41 can prevent the gas flowing inside the tube body 3 from penetrating through and passing through the resin tube body 3. That is, by providing the metal layer 41 inside the reinforcing layer 5, it is possible to obtain high damage resistance to the internal tube 3 when contacting heavy machinery from the outside, and the gas from the inside can be obtained. Leakage can be reliably prevented.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, the nylon layer 31 and the metal layer 41 may be provided simultaneously. Further, instead of the metal layer 41, a gas barrier layer for preventing the permeation of gas may be provided separately.

1, 20, 30a, 30b, 40 ......... Gas piping 3 ......... Pipe 5 ......... Reinforcement layer 6 ...... Composite tube 7 ...... Buffer layer 9 ......... Outer tube 11 ......... Ground 13 ……… Heavy machinery 21 ……… Protective layer 31 ……… Nylon layer 41 ……… Metal layer

Claims (6)

A resin outer tube is provided on the outer periphery of a composite tube including a flexible resin tube and a reinforcing layer provided on the outer periphery of the tube,
A buffer layer is provided between the outer surface of the composite tube and the inner surface of the outer tube,
When the outer tube is deformed or damaged and an external force is applied in the center direction of the composite tube, the outer surface of the composite tube can be prevented from being damaged by collapsing the buffer layer. Flexible tube for gas transport.   The flexible tube for gas transportation according to claim 1, wherein the buffer layer is formed of a resin foam.   The flexible tube for gas transportation according to claim 1 or 2, wherein a metal tape is further wound around the inner layer side of the reinforcing layer.   The flexible tube for gas transport according to any one of claims 1 to 3, wherein a protective layer made of resin is further formed on an outer periphery of the reinforcing layer of the composite tube.   The flexible tube for gas transport according to claim 4, further comprising a nylon layer on at least one of the inner layer side and the outer layer side of the protective layer. A resin-made tubular body having flexibility;
Providing a cushioning material on the outer periphery of the composite pipe comprising a reinforcing layer provided on the outer periphery of the pipe body;
The composite pipe provided with the cushioning material is inserted into a resin outer pipe and buried in the ground,
The outer pipe receives force against earth pressure from the ground,
When the outer pipe is deformed or damaged during excavation of the ground, and an external force is applied to the composite pipe in the center direction through the buffer material, the outer surface of the composite pipe is formed by the buffer material on the upper side of the composite pipe. And reducing the force applied to the outer surface of the composite pipe by bending the composite pipe itself downward by crushing the cushioning material on the lower side of the composite pipe. A method for improving the damage resistance of a flexible tube for transporting gas.

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