JP2009299752A - Composite pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite pipe for reducing damaging and breaking of an outer layer pipe, superior in heat insulation performance, and further superior in construction performance. <P>SOLUTION: This composite pipe is composed of an inner layer pipe and the outer layer pipe composed of an elastic resin material extruded so as to surround this inner layer pipe from the outside, and is formed so that the outer layer pipe has a tubular part of a plurality of layers supported so as to form an air layer between the adjacent tubular parts by a plurality of strips of interval holding ribs radially arranged at an interval in the peripheral direction, and has a plurality of strips of leg part ribs radially extending at an interval in the peripheral direction from an inner wall surface in the innermost side tubular part, received by an outer wall of the inner layer pipe and forming the air layer between the innermost side tubular part and the inner layer pipe, and is characterized in that a part tearable by hand is continuously arranged in the pipe axis direction in a tubular layer except for the outermost side tubular layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a composite pipe excellent in high heat insulation and workability, and in preventing damage to the outer surface.

  In a flexible resin tube such as cross-linked polyethylene and polybutene used for water supply and hot water supply and the like, if heat insulation is required, a polyolefin foam is coated on the outside of the resin tube. However, in composite pipes in which the resin pipe and foam are integrated before construction, the outer surface of the foam is easily damaged and torn due to dragging during construction. There is a problem that not only the body needs to be cut by the amount of the joint insertion, and that the construction takes time, but the inner resin pipe is damaged at the time of cutting.

On the other hand, a composite pipe 100 in which the periphery of the inner layer pipe 120 is covered with a tubular outer layer pipe (sheath pipe) 110 formed of a thermoplastic elastomer as shown in FIG. 9 has already been proposed (Patent Document 1). reference). That is, the composite pipe 100 is formed into a tubular shape while ensuring the scratch resistance performance, the ability to prevent tearing, and the ease of connection to the joint by forming the outer layer pipe 110 from a thermoplastic elastomer having rubber elasticity and flexibility. The ribs 112 are provided radially on the inner surface of the outer layer tube main body 111 at an equal pitch in the circumferential direction, and a heat insulating air layer 300 is formed between the inner layer tube 120 and the outer layer tube main body 111 to ensure heat insulation.
However, in the case of the composite pipe 100, the problem of being damaged or torn and connecting the joint can be solved, but the heat insulating performance is slightly inferior to that of the polyolefin foam.

Therefore, as shown in FIG. 10, the inventor of the present invention comprises an inner layer pipe 210 and an outer layer pipe 220 made of a thermoplastic elastomer extruded so as to surround the inner layer pipe 210 from the outside. A plurality of layers 220 are supported so that an air layer 260 is formed between the adjacent tubular portions 240 and 250 by a plurality of interval holding ribs 230 provided radially at intervals in the circumferential direction. 2), and the innermost tubular portion 250 is radially extended from the inner wall surface at intervals in the circumferential direction, and is received by the outer wall of the inner layer tube 210 to be the innermost tubular portion. It was considered that the above problem could be solved if the composite pipe 200 was provided with a plurality of leg ribs 280 forming the air layer 270 between the section 250 and the inner layer pipe 210.
However, since the composite pipe 200 can form the air layers 260 and 270 by providing the spacing ribs 230 and the leg ribs 280, not only can the problem of scratches and tears be solved, but also a polyolefin foam. Although the same heat insulation performance can be secured, it has been found that there are some problems in terms of workability.

  That is, in the composite pipe 200, when the end portion of the outer layer tube 220 is folded outward to expose the end portion of the inner layer tube 210, and the exposed portion is fitted and connected to the joint, the inner tubular portion 250 is folded back. It was found that the diameter of the tube had to be larger than that of the outer tubular portion 240, and it was difficult to turn back and the workability was poor.

Japanese Patent No. 3822893

  In view of the above circumstances, an object of the present invention is to provide a composite pipe with less damage and tearing of the outer layer pipe, excellent heat insulation performance, and more excellent workability.

  In order to achieve the above object, a composite pipe according to claim 1 of the present invention (hereinafter referred to as "composite pipe of claim 1") includes an inner layer pipe and an elastic resin material surrounding the inner layer pipe from the outside. The outer layer tube is supported so as to form an air layer between adjacent tubular portions by a plurality of spacing ribs provided radially at intervals in the circumferential direction. It has a multi-layered tubular part, extends radially from the inner wall surface to the innermost tubular part at intervals in the circumferential direction, and is received by the outer wall of the inner layer pipe, between the innermost tubular part and the inner layer pipe A composite pipe having a plurality of leg ribs for forming an air layer in which a portion that can be cut by hand is provided continuously in a tube axis direction in a tubular layer other than the outermost tubular layer. It is characterized by.

  The composite pipe according to claim 2 of the present invention (hereinafter referred to as "composite pipe of claim 2") is the composite pipe according to claim 1, wherein the manually tearable portion is a thin portion of the tubular layer. It is a feature.

  The composite pipe according to claim 3 of the present invention (hereinafter referred to as "composite pipe of claim 3") comprises an inner layer pipe and an outer layer pipe made of an elastic resin material surrounding the inner layer pipe from the outside, The outer layer pipe has a plurality of tubular portions supported so as to form an air layer between adjacent tubular layers by a plurality of interval holding ribs provided radially at intervals in the circumferential direction. A plurality of strips extending radially from the inner wall surface to the innermost tubular portion at intervals in the circumferential direction and received by the outer wall of the inner layer tube to form an air layer between the innermost tube portion and the inner layer tube. The outermost tubular portion has a substantially circular cross section, and the tubular portions other than the outermost tubular portion have a substantially gear-shaped cross section, The circumferential length of the tubular part is longer than the circumferential length of the outer tubular part It is characterized.

  The composite pipe according to claim 4 of the present invention (hereinafter referred to as "composite pipe of claim 4") is the composite pipe of any one of claims 1 to 3, wherein the height of the spacing rib is the rib width. It is characterized by being 2.5 times or less.

  The composite pipe according to claim 5 of the present invention (hereinafter referred to as “composite pipe of claim 5”) is the composite pipe according to any one of claims 1 to 4, and the innermost tubular portion thereof. An R shape in which the height of the spacing rib between the outer tubular portion is 4.0 times or less of the rib width, and the corner portion between the outermost tubular portion and the spacing rib is a curvature radius of 0.5 mm or more. It is characterized by being curved.

  The composite pipe according to claim 6 of the present invention (hereinafter referred to as "composite pipe of claim 6") is the composite pipe of any one of claims 1 to 5, wherein the cross-sectional area of the resin portion of the outer layer pipe is The cross-sectional area between the outer peripheral surface of the outer layer pipe and the outer peripheral surface of the inner layer pipe is 25 to 45%.

  The composite pipe according to claim 7 of the present invention (hereinafter referred to as "composite pipe of claim 7") is the composite pipe of any one of claims 1 to 6, wherein the outer layer pipe includes an elastic elastomer. It is characterized by comprising a resin material.

  In the present invention, the material of the inner tube is not particularly limited, and examples thereof include polyethylene, crosslinked polyethylene, polybutene, polypropylene, polyvinyl chloride, ethylene-vinyl acetate copolymer, thermoplastic elastomer, and the like. It may be reinforced.

  The material of the outer layer pipe is not particularly limited, and examples thereof include elastic resin materials including base resin components such as polyethylene, crosslinked polyethylene, polybutene, polypropylene, polyvinyl chloride, ethylene-vinyl acetate copolymer, and thermoplastic elastomer. When used for hot water supply or hot water supply, it is preferable to use a thermoplastic elastomer such as the composite pipe of claim 7, and among them, the one containing a polypropylene-based thermoplastic elastomer is preferable.

Although it does not specifically limit in the said elastic resin material, It is preferable that a rubber component, oil, etc. are included in addition to the said base resin component.
The rubber component is not particularly limited, but ethylene / propylene / diene copolymer rubber, ethylene propylene rubber, polyisobutylene, cis 1,4 polybutadiene, butyl rubber, styrene butylene rubber, hydrogenated styrene butylene rubber, styrene-ethylene butylene- Olefin Crystal Copolymer, Olefin Crystal-Ethylene Butylene-Olefin Crystal Copolymer, Styrene Butadiene Copolymer, Styrene-Butadiene-Styrene Block Copolymer, Styrene-Isoprene-Styrene Block Copolymer, Styrene-Ethylene-Butylene- Examples thereof include styrene block copolymers, and ethylene / propylene / diene copolymer rubbers and styrene thermoplastic elastomers are preferably used.
Although it does not specifically limit as oil, Mineral oil etc. are mentioned.

In the composite pipe of the present invention, the entire outer layer pipe is made of a foam, or most of the outer layer pipe is made of a foam, and a coating layer made of a non-foamed resin is provided on the outermost layer of the outer layer pipe. It doesn't matter.
The expansion ratio of the foam is not particularly limited, but is preferably 1.5 to 3.0 times. That is, if the expansion ratio is less than 1.5 times, improvement in heat insulation performance due to the foam cannot be expected, and if it exceeds 3.0 times, there is a possibility that a problem in strength occurs or an appearance defect is caused.

Further, the thermoplastic elastomer is not particularly limited, but it is preferable to use a thermoplastic elastomer having a high temperature tension of 40 mN or more in a molten state at 180 ° C. and an elongation at break of 100% or more. That is, when a thermoplastic elastomer having a high-temperature tension of less than 40 mN in a molten state at 180 ° C. is used, there is a possibility that a sufficient expansion ratio cannot be obtained, and a thermoplastic elastomer having an elongation at break of less than 100% may be obtained. If it is used, a sufficient expansion ratio cannot be obtained, and there is a risk that bubbles will break.
Incidentally, when the base resin is polypropylene, the blending amount of polypropylene is preferably 30 to 60% by weight of the entire elastic resin material. That is, when the blending amount of polypropylene is less than 30% by weight, there is a problem in heat resistance, and when it exceeds 60% by weight, flexibility may be poor.

In the elastic resin material, in addition to the thermoplastic elastomer, a processing aid for adjusting the melt tension and preventing the eyes may be added as necessary.
The processing aid for adjusting the melt tension is not particularly limited, but a fluorine resin such as polytetrafluoroethylene is preferable.

When polytetrafluoroethylene is used as a processing aid for adjusting the melt tension, the amount added is not particularly limited, but polytetrafluoroethylene is 1 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic elastomer. Is preferred.
That is, when the addition ratio of polytetrafluoroethylene is less than 1 part by weight relative to 100 parts by weight of the thermoplastic elastomer, the resin may be extruded from the extruder and may be broken due to insufficient tension when taken out. If it exceeds 1, the flexibility characteristic of the thermoplastic elastomer may be lost.

Further, the processing aid for preventing the eyes is not particularly limited, but an ethylene / vinyl acetate copolymer is preferable.
When an ethylene / vinyl acetate copolymer is used as a processing aid for preventing the eyes, the addition amount is not particularly limited, but the ethylene / vinyl acetate copolymer is added in an amount of 5 to 100 parts by weight of the thermoplastic elastomer. The amount is preferably 15 parts by weight.
That is, when the addition ratio of the ethylene / vinyl acetate copolymer is less than 5.0 parts by weight with respect to 100 parts by weight of the thermoplastic elastomer, a large amount of eyes may be generated, and the productivity may be lowered. If it exceeds 1, the heat resistance characteristic of the thermoplastic elastomer may be lost.

  Furthermore, additives such as pigments and inorganic fillers may be added to the elastic resin material as necessary within a range that does not impair the object of the present invention.

The coating layer is provided to obtain foam protection and surface smoothness. If this purpose can be achieved, it is preferable to reduce the thickness as much as possible, and it varies depending on the pipe diameter and the type of resin, but it is costly. In consideration of the thickness, the thickness is preferably about 0.2 mm.
The resin constituting the coating layer is not particularly limited as long as it is compatible with the resin constituting the foam, and examples thereof include polyethylene, polypropylene, and a thermoplastic resin elastomer.

  In addition, as for the addition amount of the foaming agent added in order to form a foam, 1.0-10 weight part of a foaming agent is preferable with respect to 100 weight part of thermoplastic elastomers. That is, if the foaming agent is less than 1.0 part by weight, a foaming ratio of 1.5 times or more cannot be obtained, and if it exceeds 10 parts by weight, the foaming ratio exceeds 3 times, resulting in poor appearance or There is a risk of tearing due to insufficient strength of the surface.

The foaming agent used for producing the composite pipe of the present invention is not particularly limited, and examples thereof include azodicarbonamide, hydrazodicarbonamide, azodicarboxylic acid barium salt, nitrosoguanidine, p, p ^, -oxybis. Thermal decomposition types such as benzenesulfonyl semicarbazide, benzenesulfonylhydrazide, N, N ^, -dinitrosopentamethylenetetramine, toluenesulfonylhydrazide, 4,4-oxybis (benzenesulfonylhydrazide), azobisisobutyronitrile, sodium bicarbonate, Thermally expandable foam particles and the like may be used, and these foaming agents may be used in combination. However, it is preferable to use at least thermally expandable foam particles, and a combination of sodium hydrogen carbonate and thermally expandable foam particles is more preferable. preferable.

The thermally expandable foamed particles refer to radical polymerizable monomers such as ethane, ethylene, propane, propene, n-butane, iso-butane, butene, iso-, as described in JP-A-2006-45532. Low molecular weight hydrocarbons such as butene, n-pentane, iso-pentane, n-hexane, heptane, petroleum ether, n-octane, iso-octane; CCl ₃ F, CCl ₂ F ₂ , CClF ₃ , CClF ₂ -CCl ₂ F and other chlorofluorocarbons; particles obtained by suspension polymerization in the presence of a volatile swelling agent such as tetramethylsilane, trimethylethylsilane, trimethylisopropylsilane, and trialkyl-n-propylsilane. For example, commercially available products such as trade name Microsphere F manufactured by Matsumoto Yushi Co., Ltd. can be used. .

When a coating layer is provided on the foam as described above, the resin composition forming the coating layer is extruded onto the resin composition constituting the foam before the resin composition constituting the foam is solidified. It is preferable to mold.
That is, it is preferable that the foam and the coating layer are thermally bonded from the viewpoint of workability and appearance.
In the composite pipe of the present invention, the number of layers of the tubular portion is not particularly limited, but it is preferably 2 to 3 layers in consideration of productivity and handleability.

In the composite pipe of claim 1, the method for providing the tearable portion by hand is not particularly limited. For example, a method for providing a low-strength portion such as a weld line generated during resin molding, or a method for providing a thin portion. However, it is preferable to provide a thin portion as in the composite pipe of claim 2.
The thickness of the thin portion is not particularly limited, but may be about 0.05 mm to 0.1 mm when the outer tube is formed of a thermoplastic elastomer.

  4. The composite pipe according to claim 3, wherein the peripheral length of the inner tubular portion is preferably longer than the peripheral length of the outer tubular portion. For example, when the tubular portion has two layers, the inner tubular portion Is obtained by the formula 4 × π × t (2π (r + t) −2πr) from the outer peripheral length of the outer tubular portion, where π is the circumferential ratio and t is the air layer thickness between the tubular portions. , R is a radius from the tube center of the inner tubular portion) and is preferably longer.

The number and shape of the spacing ribs are not particularly limited as long as a predetermined air layer can be secured between the tubular portion and the tubular portion. However, as in the composite pipe of claim 4, the height of the spacing ribs is rib. The width is preferably 2.5 times or less.
That is, if the height of the spacing ribs exceeds 2.5 times the rib width, when the composite pipe is bent at the time of construction, the ribs of the coating layer are twisted (lateral buckling) at the inner part of the bend. Wrinkles will occur on the surface of the outer layer tube, and the appearance after construction may be deteriorated.

Further, as in the composite pipe according to claim 5, the spacing ribs have a height of the spacing ribs of 4.0 times or less of the rib width, and the corner portion between the outermost tubular portion and the spacing ribs has a curvature. It is good also as a structure curved in the R shape of radius 0.5mm or more.
That is, if the corner portion between the outermost tubular portion and the spacing rib is curved in an R shape having a radius of curvature of 0.5 mm or more, the height of the spacing rib may exceed 2.5 times the rib width. Unless the height of the spacing ribs exceeds 4.0 times the rib width, when the composite pipe is bent at the time of construction, the ribs of the coating layer cause torsion (lateral buckling) at the inner part of the bend. There is no risk that wrinkles will enter the surface of the outer tube and the appearance after construction will not deteriorate.

  Further, the cross-sectional area of the resin portion of the outer layer pipe is not particularly limited, but as in the composite pipe of claim 6, 25 to 45% of the cross-sectional area between the outer peripheral surface of the outer layer pipe and the outer peripheral surface of the inner layer pipe. It is preferable that That is, if the cross-sectional area of the resin portion of the outer tube is too small, there may be a problem with the strength of the outer tube, and if the cross-sectional area of the resin portion of the outer tube is too large, a sufficient heat insulating effect may not be obtained. is there.

  As described above, the composite pipe according to claim 1 is composed of an inner layer pipe and an outer layer pipe made of an elastic resin material surrounding the inner layer pipe from the outside, and the outer layer pipes are radially spaced apart in the circumferential direction. It has a plurality of tubular portions supported so as to form an air layer between adjacent tubular layers by a plurality of spaced spacing ribs provided, and is spaced in the circumferential direction from the inner wall surface to the innermost tubular portion. A composite tube having a plurality of leg ribs extending radially and spaced apart from each other and received by the outer wall of the inner layer tube to form an air layer between the innermost tubular portion and the inner layer tube, Since the tearable portion is continuously provided in the tube axial direction on the tubular layer other than the outermost tubular layer, the tubular portion can be axially cut by the manually tearable portion except for the outermost tubular portion. Can be easily torn.

Therefore, even if the outer layer tube is formed of a resin that is not easily elastically deformed, the end portion of the outer layer tube can be easily folded outward if the tearable portion of the inverted portion of the tubular portion is torn.
That is, connection work to the joint can be easily performed. Of course, since the air layer is provided, the heat insulation performance is excellent, and since the outer layer pipe is provided, the inner layer pipe serving as the pipe body is hardly damaged.

  In addition, the composite pipe of claim 1 can be accurately formed by extruding by manually forming the part that can be cut by hand, as in the case of the composite pipe of claim 2, if the part that can be cut by hand is a thin part of the tubular layer. can do.

  The composite pipe according to claim 3 is composed of an inner layer pipe and an outer layer pipe made of an elastic resin material surrounding the inner layer pipe from the outside, and the outer layer pipes are radially provided at intervals in the circumferential direction. A plurality of tubular portions supported so as to form an air layer between adjacent tubular layers by the spacing retaining ribs, and radially spaced from the inner wall surface in the circumferential direction to the innermost tubular portion. A composite tube comprising a plurality of leg ribs extending and received by the outer wall of the inner layer tube to form an air layer between the innermost tubular portion and the inner layer tube, wherein the outermost tubular portion is The cross section has a substantially circular shape, and the tubular portion other than the outermost tubular portion has a substantially cross-sectional gear shape, and the circumferential length of the inner tubular portion is longer than the circumferential length of the outer tubular portion. ing. That is, since the inner tubular portion is curved between the spacing ribs, if the end portion of the outer tube is reversed, the curved portion extends in a straight line and can be easily reversed.

Therefore, even if the outer tube is made of a resin that is not easily elastically deformed, the end of the outer tube can be easily folded outward.
That is, connection work to the joint can be easily performed. Of course, since the air layer is provided, the heat insulation performance is excellent, and since the outer layer pipe is provided, the inner layer pipe serving as the pipe body is hardly damaged.

  Further, as in the composite pipe of claim 4, the height of the spacing rib is set to 2.5 times or less of the rib width, or as in the composite pipe of claim 5, the innermost tubular portion and its The height of the spacing rib between the outer tubular portion is 4.0 times or less the rib width, and the corner portion between the outermost tubular portion and the spacing rib has a radius of curvature of 0.5 mm or more. If the composition is curved in shape, when the composite pipe is bent during construction, the ribs of the coating layer cause twisting phenomenon (lateral buckling) at the inner part of the bend, and the outer pipe surface is wrinkled. In addition, there is no risk that the appearance after construction will deteriorate.

And like the composite pipe of claim 6, when the cross-sectional area of the resin portion of the outer layer pipe is 25 to 45% of the cross-sectional area between the outer peripheral surface of the outer layer pipe and the outer peripheral surface of the inner layer pipe, The outer tube can be surely provided with sufficient strength and heat insulation performance.
Furthermore, if the outer layer pipe is formed of an elastic resin material containing a thermoplastic elastomer as in the composite pipe of claim 7, the composite pipe is damaged or broken, and the problem of workability when connecting the joints In addition to being effective in solving the problem, it can be suitably used for water supply and hot water supply.

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof.
FIG. 1 shows a first embodiment of a composite pipe according to the present invention.

As shown in FIG. 1, the composite pipe 1a includes a cross-linked polyethylene inner layer pipe 2 and a tubular thermoplastic elastomer (for example, olefin resin (PP, PE) provided so as to surround the inner layer pipe 2). The outer layer pipe 3a made of Mitsubishi Chemical Corp. thermorun in which an olefinic rubber (EPR, EPDM) is finely dispersed in the above matrix.
The outer layer tube 3 a includes an outer layer tube main body 4 a and a coating layer 5.

The outer tube main body 4a is made of a thermoplastic elastomer 2 to 5 times foam, and includes two tubular portions 41, 42, twelve spacing ribs 43, and twelve leg ribs 44. .
The two tubular portions 41 and 42 are provided substantially concentrically around the central axis of the inner layer tube 2, and the inner tubular portion 42 is provided with 12 thin-walled portions 42a continuous in the axial direction at equal pitches in the circumferential direction. It has been.
The thin-walled portion 42a is formed to have a minimum thickness of 0.05 mm to 0.1 mm by providing a substantially U-shaped concave groove 42b on the outer peripheral surface of the tubular portion 42 so that it can be easily cut by hand. It has become.

The interval holding ribs 43 are provided radially at equal intervals in the circumferential direction at an intermediate position between the thin portion 42a and the thin portion 42a, and maintain the interval between the tubular portion 41 and the tubular portion 42 so as to be between the tubular portions 41, 42. The outer air layer 45a is formed continuously in the tube axis direction.
The spacing rib 43 has a height of 4.0 times or less of the rib width, and the corner portions of the tubular portions 41 and 42 and the spacing rib are curved into an R shape having a curvature radius of 0.5 mm or more. ing.

  The leg ribs 44 extend from the position corresponding to the interval holding ribs 43 of the inner tubular portion 42 in the direction of the inner layer tube 2 in a tapered shape having an inverted triangular cross section, and abut the outer peripheral surface of the inner layer tube 2 at the apex portion. An inner air layer 45 b that is continuous in the tube axis direction is formed between the portion 42 and the inner layer tube 2.

The coating layer 5 is non-foamed, is formed of the same thermoplastic elastomer as the outer layer tube main body 4a, and covers the entire outer peripheral surface of the outer layer tube main body 4a.
Further, in this composite pipe 1a, the cross-sectional area of the resin portion of the outer layer pipe 3a has a section between the outer peripheral surface of the inner layer pipe 2 and the outer peripheral surface of the outer layer pipe 3a including the air layer 45a and the air layer 45b. It is 25 to 45% of the area.

  The method for manufacturing the composite pipe 1a is not particularly limited. For example, the cross-linked polyethylene pipe that becomes the inner-layer pipe 2 is extruded, and the outer-layer pipe 3a and the outer-layer pipe main body 4a are formed around the extruded cross-linked polyethylene pipe. The coating layer 5 can be obtained by coextrusion molding.

  As described above, since the outer tube 3a is formed of a thermoplastic elastomer, the composite tube 1a is hard to be damaged and excellent in strength, and has air layers 45a and 45b, so that the heat insulating performance is also provided. Are better. Moreover, since the inner tubular portion 42 is provided with a thin portion 42a that can be cut by hand, it is not shown, but if the thin portion 42a is torn when connecting the pipe end to the joint, the outer layer The tube end portion of the inner layer tube 2 can be easily exposed by inverting the tube end portion of the tube 3a. Therefore, piping workability such as connection work to the joint is improved.

FIG. 2 shows a second embodiment of the composite pipe according to the present invention.
As shown in FIG. 2, the composite pipe 1b is the same as the composite pipe 1a except that the outer pipe main body 4b of the outer pipe 3b has a leg rib 44 at a position shifted from the spacing rib 43. It has become.
That is, the composite pipe 1b has the same effect as the composite pipe 1a, and the leg ribs 45 are provided at positions shifted from the spacing ribs 44. Therefore, the inner pipe 2 through the outer pipe 3b. In addition, the heat conduction path to the outside of the composite pipe 1b becomes longer, and the heat insulation performance is further improved.

FIG. 3 shows a third embodiment of the composite pipe according to the present invention.
As shown in FIG. 3, this composite pipe 1 c is formed except that the outer pipe main body 4 c of the outer pipe 3 c is formed by providing a thin groove 42 c with a substantially V-shaped groove 42 d on the outer peripheral surface of the tubular portion 42. Is the same as that of the composite pipe 1a.

FIG. 4 shows a fourth embodiment of the composite pipe according to the present invention.
As shown in FIG. 4, this composite pipe 1d is formed by providing the outer-layer pipe main body part 4d of the outer-layer pipe 3d by providing a thin-walled part 42e with a substantially U-shaped concave groove 42f on the inner peripheral surface of the tubular part 42. Except for this, it is the same as the composite pipe 1a.

FIG. 5 shows a fifth embodiment of the composite pipe according to the present invention.
As shown in FIG. 5, this composite pipe 1e is the same as the composite pipe 1a except that the outer layer pipe main body 4e of the outer layer pipe 3e is as follows.

  That is, the outer tube main body 4e is substantially U-shaped toward the inner tube 2 between the leg ribs 44 and the leg ribs 44 of the tubular portion 46, instead of providing a thin portion on the inner tubular portion 46. A curved portion 46a that is curved in a letter shape is formed, and the peripheral length of the inner tubular portion 46 is expressed by the formula (4 × π × t (t is the thickness of the air layer 45a)) from the outer peripheral length of the tubular layer 41. It is longer than the required length.

  In the composite pipe 1e, as described above, since the peripheral length of the inner tubular portion 46 is longer than the outer peripheral length of the tubular layer 41, when the tube end portion of the outer layer tube 3e is reversed, the curved portion 46a. Therefore, the tube end portion of the inner layer tube 2 can be easily exposed.

FIG. 6 shows a sixth embodiment of the composite pipe according to the present invention.
As shown in FIG. 6, the composite pipe 1f is the same as the composite pipe 1a except that the outer layer pipe body 4f of the outer layer pipe 3f is as follows.

  That is, the outer tube main body 4f is curved in a substantially U shape outwardly between the leg rib 44 and the leg rib 44 of the tubular portion 47, instead of providing a thin portion on the inner tubular portion 47. And the circumferential length of the inner tubular portion 47 is determined by the formula (4 × π × t (t is the thickness of the air layer 45a)) from the outer circumferential length of the tubular layer 41. It is longer than a minute.

FIG. 7 shows a seventh embodiment of the composite pipe according to the present invention.
As shown in FIG. 7, the composite tube 1g is the same as the composite tube 1f except that the outer layer tube main body 4g of the outer layer tube 3g is as follows.

  That is, the outer-layer tube main body 4g is provided with a substantially V-shaped bent portion 48a in the inner tubular portion 48 instead of the curved portion 47a that bends in a substantially U shape, and the tip of the bent portion 48a is disposed on the inner layer. The bent portion 48a is used as a leg rib in contact with the outer peripheral surface of the tube 2, so that the leg rib continuous to the interval holding rib 43 is eliminated.

FIG. 8 shows an eighth embodiment of the composite pipe according to the present invention.
As shown in FIG. 8, this composite tube 1h is the same as the composite tube 1g except that the bent portion 49a of the outer layer tube main body 4h of the outer layer tube 3h has a cross-sectional waveform. In FIG. 8, 49 is an inner tubular part.

It is sectional drawing showing 1st Embodiment of the composite pipe | tube concerning this invention. It is sectional drawing showing 2nd Embodiment of the composite pipe concerning this invention. It is sectional drawing showing 3rd Embodiment of the composite pipe | tube concerning this invention. It is sectional drawing showing 4th Embodiment of the composite pipe concerning this invention. It is sectional drawing showing 5th Embodiment of the composite pipe concerning this invention. It is sectional drawing showing 6th Embodiment of the composite pipe concerning this invention. It is sectional drawing showing 7th Embodiment of the composite pipe concerning this invention. It is sectional drawing showing 8th Embodiment of the composite pipe | tube concerning this invention. It is sectional drawing of the conventional composite pipe. It is sectional drawing of the composite pipe which the inventor of this invention proposed previously.

Explanation of symbols

1a, 1b, 1c, 1d, 1e, 1f, 1g, 1h Composite tube 2 Inner layer tube 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h Outer layer tube 4a, 4b, 4c, 4d, 4e, 4f, 4g 4h Outer tube main body 41 Tubular part (outside)
42, 46, 47, 48, 49 Tubular part (inside)
42a, 42c, 42e Thin wall portion 43 Interval holding rib 44 Leg ribs 45a, 45b Air layers 46a, 47a Curved portions 48a, 49a Bent portion 5 Cover layer

Claims (7)

An inner layer tube and an outer layer tube made of an elastic resin material that surrounds the inner layer tube from the outside, and the outer layer tube is adjacent to each other by a plurality of spaced spacing ribs provided radially in the circumferential direction. A plurality of tubular portions supported so as to form an air layer between them and extending radially from the inner wall surface to the inner wall surface at intervals in the circumferential direction; A composite pipe comprising a plurality of leg ribs which is received and forms an air layer between the innermost tubular section and the inner layer pipe;
A composite tube characterized in that a portion that can be cut by hand is provided continuously in a tube axis direction in a tubular layer other than the outermost tubular layer.   The composite pipe according to claim 1, wherein the manually tearable part is a thin part of the tubular layer. An inner layer tube and an outer layer tube made of an elastic resin material that surrounds the inner layer tube from the outside, and the outer layer tube is adjacent to each other by a plurality of spaced spacing ribs provided radially in the circumferential direction. A plurality of tubular portions supported so as to form an air layer between them and extending radially from the inner wall surface to the inner wall surface at intervals in the circumferential direction; A composite pipe comprising a plurality of leg ribs which is received and forms an air layer between the innermost tubular section and the inner layer pipe;
The outermost tubular part has a substantially circular cross section, and the tubular parts other than the outermost tubular part have a substantially gear-shaped cross section, and the inner tubular part has a peripheral length of the outer tubular part. A composite pipe characterized in that it is formed longer than the circumferential length of.   The composite pipe according to any one of claims 1 to 3, wherein a height of the spacing rib is 2.5 times or less of a rib width.   The height of the spacing rib between the innermost tubular portion and one outer tubular portion is 4.0 times or less of the rib width, and the corner portion between the outermost tubular portion and the spacing rib is The composite pipe according to any one of claims 1 to 4, wherein the composite pipe is curved into an R shape having a curvature radius of 0.5 mm or more.   The composite pipe according to any one of claims 1 to 5, wherein the cross-sectional area of the resin portion of the outer pipe is 25 to 45% of the cross-sectional area between the outer peripheral face of the outer pipe and the outer peripheral face of the inner pipe. .   The composite pipe according to any one of claims 1 to 6, wherein the outer pipe is made of an elastic resin material containing a thermoplastic elastomer.

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