JP6523023B2 - Heat insulation piping system - Google Patents

Description

  The present invention relates to an insulation piping system. More specifically, the present invention relates to an adiabatic piping system in which the heat insulation effect is well maintained.

  BACKGROUND ART Conventionally, metal piping, particularly carbon steel pipe for piping (SGP) for piping, is mainly used as a piping material for hot and cold water of an air conditioning and heating fan coil. However, piping systems using metal piping have the problems of easy rusting and earthquake resistance (strain resistance) due to the characteristics of the material, and problems of piping workability and securing of building strength due to being heavy. There is.

  On the other hand, resin piping can solve the problems of easy rustability, earthquake resistance, piping workability, and building strength securing among the problems that metal piping has. Therefore, attempts have been made to replace metal piping with resin piping. For example, Japanese Patent Application Laid-Open No. 2002-256024 (Patent Document 1) has characteristics such as rigidity, creep characteristics, impact resistance strength, pressure resistance strength, heat resistance, abrasion resistance, flexibility, and crystallization speed. Furthermore, a pipe material for cold and hot water, which is made of a polybutene resin excellent in the balance between moldability, particularly high-speed formability of a small diameter pipe, and pressure resistance is disclosed.

Unexamined-Japanese-Patent No. 2002-256024

  The cold and hot water pipe of the above polybutene resin has heat resistant properties, which is the property of the resin itself. Therefore, the piping system has only a slight heat resistance improvement effect, and for example, a high degree of heat insulation which can prevent the occurrence of condensation can not be achieved.

  The present inventors adopted means for covering the surface of resin made piping for hot and cold water with a fibrous heat insulating material in order to significantly improve the heat insulation of the piping system. The heat insulating material has a large specific surface area to exhibit its characteristics, and contains a large amount of air. Therefore, the heat insulating material brings much air into contact with the surface of the pipe to exhibit the heat insulating property. However, when cold water flows in the piping, the air condenses depending on the temperature of the air in contact with the piping surface. When the heat insulating material gets wet due to condensation, the heat insulating effect decreases. In particular, in the case of a fibrous heat insulating material having air permeability, an environment in which condensation occurs repeatedly occurs, so that the heat insulating property is seriously deteriorated by the heat insulating material getting wet.

  Therefore, an object of the present invention is to provide an adiabatic piping system in which a high degree of thermal insulation effect is well maintained.

  In order to achieve the above object, the present invention includes the following inventions.

(1)
The heat insulation piping system of the present invention includes resin piping, a heat insulation fiber layer, and a covering layer. The heat insulating fiber layer covers the outer peripheral surface of the resin pipe. Furthermore, the heat insulation fiber layer includes a skin layer on the surface on the resin piping side. The covering layer covers the outer peripheral surface of the heat insulating fiber layer.

Thus, since the resin piping is covered with the heat insulation fiber layer, a high degree of heat insulation effect can be obtained. Furthermore, since the heat insulation fiber layer includes the skin layer on the surface on the resin pipe side, the air contacting the outer peripheral surface of the resin pipe is reduced, and the occurrence of dew condensation can be suppressed. Furthermore, the covering layer covers the outer peripheral surface of the heat insulating fiber layer, thereby preventing wetting from the outer peripheral surface side of the heat insulating fiber layer and suppressing permeation of moisture-containing air.
Therefore, the above-described configuration well maintains a high degree of thermal insulation.

In addition, resin piping is used as piping for flowing cold water at least.
The skin layer is a layer that constitutes the inner peripheral surface of the heat insulating fiber layer, and specifically, can be embodied by relatively increasing the fiber density and / or including the binder resin. it can.

(2)
The average density of the heat insulating fiber layer may be 20 kg / m ³ or more and 100 kg / m ³ or less.
By this configuration, a good heat insulating effect can be obtained.

(3)
The heat insulating fiber layer may include a plurality of thin tubular layers having a density higher than the average density substantially concentrically.

  According to this configuration, in the interior of the heat insulating fiber layer, there are many layers with high fiber density in the radial direction, so it is difficult for air to permeate in the radial direction. Therefore, the progress of condensation can be further favorably suppressed.

(4)
The resin pipe may be a multilayer pipe including a first layer, a second layer, and a third layer in the direction from the axial center to the outer periphery. In this case, the first layer is a thermoplastic resin, the second layer is a thermoplastic resin containing fibers, and the third layer is a thermoplastic resin.

This configuration is particularly useful when the resin pipe is a pipe through which cold and hot water flows.
Since resin piping inherently has a large linear expansion coefficient compared to metal piping, heat expansion and contraction due to the flow of cold and hot water in the piping is large, and the second layer is a resin containing fibers. Is suppressed and the dimensional stability is excellent. Therefore, even when cold / hot water flows in the piping, it is possible to preferably prevent the gap or distortion at the joint of the heat insulating fiber layer. For this reason, the stable thermal insulation effect can be acquired in a wide temperature range.

(5)
The fiber diameter of the fibers contained in the second layer is preferably larger than the fiber diameter of the fibers constituting the heat insulating fiber layer.

  With this configuration, in the heat insulating fiber layer in which thinner fibers are used, the thin fibers are easily intertwined to form an air phase, while the preferable heat insulating property is provided, whereas in the second layer of resin piping in which thicker fibers are used Have favorable strength and rigidity.

(6)
It is preferable that the fiber diameter of the fiber which comprises a heat insulation fiber layer is 5 micrometers or more and 10 micrometers or less, and the fiber diameter of the fiber contained in a 2nd layer is 12 micrometers or more and 50 micrometers or less.

  With this configuration, the heat insulating fiber layer has more preferable heat insulating property, whereas the second layer of resin piping has more preferable strength and rigidity.

(7)
It is preferable that the fiber length of the said fiber contained in a 2nd layer is larger than the fiber length of the fiber which comprises a heat insulation fiber layer.

  With this configuration, in the heat insulating fiber layer in which longer fibers are used, the shape in which the long fibers are entangled is less likely to be broken, and a preferable maintained heat insulating property can be provided. The two layers provide good formability and easy control of the orientation of the short fibers.

(8)
It is preferable that the fiber length of the fiber which comprises a heat insulation fiber layer is more than 5 mm, and the fiber length of the fiber contained in a 2nd layer is 5 mm or less.

  With this configuration, in the heat insulating fiber layer, the shape in which long fibers are entangled is less likely to be broken, and the heat insulating property maintained more preferably can be provided, while the second layer of resin piping has better formability. In addition, control of the orientation of short fibers is easier.

  In addition, although the upper limit included in the range of the fiber length of the fiber which comprises a heat insulation fiber layer is not specifically limited, For example, 15 mm may be sufficient. Also, the lower limit value included in the range of the fiber length of the fibers contained in the second layer is not particularly limited, but the fiber length of the fibers contained in the second layer is, for example, 0.10 mm or more from the viewpoint of strength and rigidity. Is preferred.

(9)
When the relative thickness of the first layer is 1, it is preferable that the relative thickness of the second layer is 2 or more and 6 or less, and the relative thickness of the third layer is 0.5 or more and 2 or less.

  With this configuration, thermal expansion and contraction of the resin piping can be preferably suppressed, and excellent dimensional stability can be provided. Therefore, a more stable thermal insulation effect can be obtained in a wide temperature range.

(10)
The content of fibers in the second layer is preferably 10% by weight or more and 60% by weight or less, where the total weight of the resin composition for producing the second layer is 100% by weight.

  By this configuration, it is possible to provide good formability while preferably providing dimensional stability.

(11)
The ten-point average roughness Rz of at least one of the interface between the first layer and the second layer and the interface between the second layer and the third layer is preferably 30 μm or more.

With this configuration, the layer interface is sufficiently rough, so interface peeling is unlikely to occur even when the resin pipe is deformed. In the present specification, the deformation that the resin piping can receive includes deformation due to the load of external force, temperature change, humidity change, and deformation due to environmental change such as aged deterioration.
The upper limit value included in the range of the ten-point average roughness Rz is not particularly limited, but is, for example, 300 μm from the viewpoint of manufacturability and the like. The ten-point average roughness Rz is a measured value in accordance with JIS B 0601.

(12)
In the heat insulation piping system of the above (1) to (3), the resin piping may be made of a polyolefin resin, and the covering layer may also be made of a polyolefin resin.

  With this configuration, the resin pipe has good flexibility and is excellent in earthquake resistance, and the mechanical properties of the resin pipe and the cover layer are uniform, so the heat expansion and contraction of the cover layer is similarly performed when the resin pipe is thermally expanded and contracted. By doing this, the effect of preventing wetting from the outer peripheral surface side of the heat insulating fiber layer and the effect of suppressing permeation of air containing moisture can be stably maintained.

It is a partially cutaway sectional view of the heat insulation piping system of a 1st embodiment. It is a schematic cross section of the heat insulation piping system of FIG. 1, and its elements on larger scale. It is a typical sectional view of the heat insulation piping system of a 2nd embodiment, and its elements on larger scale. It is a typical sectional view of resin piping in the heat insulation piping system of a 3rd embodiment. It is a schematic cross section of the 1st modification of resin piping in the heat insulation piping system of a 3rd embodiment. It is a partially expanded view of FIG. It is a schematic cross section of the 2nd modification of resin piping in the heat insulation piping system of a 3rd embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same elements are denoted by the same reference numerals, and the names and functions thereof are also the same. Therefore, detailed description about them will not be repeated.

First Embodiment
FIG. 1 is a partially cutaway cross-sectional view of the heat insulation piping system of the first embodiment. FIG. 2 is a schematic cross-sectional view of the heat insulation piping system of FIG. 1 and a partially enlarged view thereof.
The heat insulation piping system 100 shown in FIGS. 1 and 2 includes a resin pipe 200, a heat insulation fiber layer 400, and a covering layer 510. The heat insulation piping system 100 can further include a decorative sheet 520 and a restraint member 530 as shown in FIG. 1 (these elements are omitted in FIG. 2).

[Resin piping 200]
The resin pipe 200 is a pipe used for a hot and cold water pipe, a water and sewage pipe, and the like. The resin pipe 200 is mainly made of a polyolefin resin. By this, the piping itself has flexibility, and good earthquake resistance can be obtained.

  It does not specifically limit as polyolefin resin. For example, polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-α-olefin copolymer and the like can be mentioned. From the viewpoint of effectively enhancing the strength of the molded body, elongation at high temperature, and the like, polyethylene, polypropylene and polybutene are preferably selected, and polyethylene is more preferable.

Furthermore, as polyethylene (PE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE) and the like can be mentioned. Examples of polypropylene (PP) include homoPP, block PP and random PP. As polybutene, polybutene-1 etc. are mentioned. The ethylene-α-olefin copolymer is composed of several mol% of α-olefin such as propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene or 1-octene with respect to ethylene. It is preferable that it is a copolymer copolymerized in the ratio of
One of these polyolefin resins may be used alone, or two or more thereof may be used in combination.

  The resin pipe 200 may have a single-layer structure or a multi-layer structure. The resin constituting the resin pipe 200 (in the case of a multilayer structure, the resin constituting a part of the layer) may be a fiber reinforced resin (described later), and may be a foamed resin.

The resin pipe 200 is connected by a joint not shown. The joint is also preferably made of a polyolefin resin as a main component. By this, since the connecting part of the pipe also has flexibility, for example, even if the axial directions of the resin pipes 200 connected to each other are mutually displaced by an earthquake or the like, the joint is bent and both resin pipes are bent. It can follow 200 deviations. Therefore, earthquake resistance can be obtained as the whole heat insulation piping system 100.
As will be described later, although the outer peripheral surface of the illustrated resin pipe 200 is coated in multiple layers, the outer peripheral surface of the joint connecting the resin pipe 200 is also coated similarly without distinction.

[Adiabatic fiber layer 400]
The heat insulating fiber layer 400 covers the entire outer peripheral surface of the resin pipe 200. In FIG. 1, two heat insulating fiber layers 400 are axially joined to one resin pipe 200. The heat insulating fiber layer 400 is not particularly limited as long as it is configured to include a large amount of air and to increase the specific surface area by entangled fibers in three dimensions. For example, inorganic fibers are preferably employed as the heat insulating fiber layer 400 from the viewpoint of fire spread prevention. Specific examples of the inorganic fibers include glass fibers, ceramic fibers, artificial mineral fibers and the like. The fibers are preferably in a non-woven state in terms of containing a large amount of air.

The average density of the heat insulating fiber layer 400 is, for example, 20 kg / m ³ or more and 100 g / m ³ or less, preferably 45 kg / m ³ or more and 90 kg / m ³ or less. By this, a good heat insulation effect can be obtained. The thickness of the heat insulation fiber layer 400 may be 2% or more and 400% or less, preferably 5% or more and 350% or less, and more preferably 15% or more and 135% or less of the outer periphery radius of the resin pipe 200. By this, a good heat insulation effect can be obtained.

  Although the fiber diameter of the fiber which comprises the heat insulation fiber layer 400 is not specifically limited, For example, they are 5 micrometers or more and 10 micrometers or less. When the thickness is an appropriate thickness equal to or more than the above lower limit value, it is easy to maintain the shape in which the fibers are entangled three-dimensionally, and by being an appropriate thinness less than the above upper limit value, it is easy to form an air phase efficiently Therefore, preferable heat insulation can be provided. In addition, a fiber diameter is an average of the largest diameter of the cross section of the fiber which comprises the heat insulation fiber layer 400. FIG.

  Although the fiber length of the fiber which comprises the heat insulation fiber layer 400 is not specifically limited, For example, more than 5 mm, Preferably it is 7 mm or more, More preferably, it is 9 mm or more. By this, the shape in which the fibers are entangled is unlikely to be broken, and it is possible to provide heat insulation which is preferably maintained. Although the upper limit included in the range of the fiber length which comprises a heat insulation fiber layer is not specifically limited, For example, 20 mm, Preferably it may be 15 mm. The fiber length is the average of the lengths of the fibers constituting the heat insulating fiber layer 400.

  The heat insulating fiber layer 400 includes a skin layer 410 in contact with the outer peripheral surface of the resin pipe 200 and a heat insulating layer 420 occupying the other portion. The skin layer 410 may be configured to reduce air contacting the outer circumferential surface as compared with the case where the heat insulating layer 420 directly contacts the outer circumferential surface of the resin pipe 200. That is, the skin layer 410 is configured to have a smaller specific surface area than the heat insulating layer 420. By this, the air which contacts the outer peripheral surface of resin piping 200 is reduced, and it can control dew condensation generating.

  The skin layer 410 may be embodied, for example, by making the fiber density higher than the heat insulating layer 420, containing a binder resin, or making the fiber density higher than the heat insulating layer 420 and containing a binder resin. it can.

When the fiber density of the skin layer 410 is larger than the fiber density of the heat insulating layer 420, the average density of the heat insulating fiber layer 400 is preferably higher. In this case, for example, it may be 1.1 times or more and 3 times or less the average density of the heat insulating fiber layer 400, or 22 kg / m ³ or more and 300 kg / m ³ or less, preferably 26 kg ³ or more and 300 kg / m ³ or less, More preferably, it may be 50 kg / m ³ or more and 300 kg / m ³ or less. More preferably, the skin layer 410 is configured to have a small specific surface area to the extent that air does not permeate. By this, the surface of the skin layer 410 becomes smoother and is likely to be along the outer surface of the resin pipe 200, the air in contact with the outer peripheral surface of the resin pipe 200 is eliminated as much as possible, and dew condensation can be suppressed more preferably.

  When the binder resin is contained in the skin layer 410, the binder resin intervenes between the fiber and the fiber by coating the surface of the fiber with the binder resin. Therefore, the specific surface area is reduced by narrowing the distance between the fibers. Alternatively, the binder resin stably maintains the surface smoothness of the skin layer 410 by fixing the state in which the fibers are compressed and the specific surface area is reduced so that the surface of the skin layer 410 is smooth. The binder resin is not particularly limited, and examples thereof include thermosetting resins such as phenol resins.

  The thickness of the skin layer 410 may be, for example, 0.3 mm or more and 7 mm. A diameter of 0.3 mm or more is preferable in that the outer peripheral surface of the resin pipe 200 can be sufficiently covered, and a diameter of 7 mm or less is preferable in that the heat insulation performance of the entire heat insulation fiber layer 400 is well maintained. From the viewpoint of effectively suppressing the progression of condensation by reducing the amount of air itself near the outer surface of the resin piping 200 and reducing the amount of water contained in the air, the thickness of the skin layer 410 is more preferably 0. It is 5 mm or more and 6 mm or less, more preferably 1 mm or more and 5 mm or less.

[Covering Layer 510]
The covering layer 510 covers the entire surface of the heat insulating fiber layer 400. While this prevents the wetting from the outer peripheral surface side of the heat insulation fiber layer 400, permeation | transmission of the air containing moisture is suppressed. As shown in FIG. 1, the covering layer 510 also shields the seam S of the axially spliced insulation fiber layer 400. This also suppresses the inflow of damp air from the joint S.

  The material of the covering layer 510 may be a non-water permeable material. Specifically, non-foamed resin, that is, solid resin is preferable. By covering the surface of the heat insulating fiber layer 400 with such a water impermeable covering layer 510, it is possible to waterproof the heat insulating fiber layer 400 and to prevent a decrease in heat insulation due to wetting.

  Furthermore, when the resin pipe 200 is made of a polyolefin resin, it is more preferable that the material of the covering layer 510 is also a polyolefin resin. By this, the mechanical properties of the resin piping 200 and the covering layer 510 are equalized, so that when the resin piping 200 is thermally expanded and contracted, the covering layer 510 is similarly thermally expanded and contracted from the outer peripheral surface side of the heat insulating fiber layer 400. It is possible to stably maintain the anti-wetting effect and the anti-permeation effect of damp air.

  As polyolefin resin which may comprise the coating layer 510, what was illustrated above as resin which comprises the resin piping 200 can be used, without specifically limiting. The polyolefin resin constituting the resin pipe 200 and the polyolefin resin constituting the covering layer 510 may be identical to or different from each other.

[Cosmetic sheet 520, restraint member 530]
The decorative sheet 520 covers the entire surface of the covering sheet 510. This makes it possible to obtain good appearance. The decorative sheet 520 preferably has a metal film. The decorative sheet 520 may be in a mode in which a metal film is laminated on one surface of a substrate. In this case, the substrate may be coated so as to be on the side of the coating sheet 510, or the metal film may be coated so as to be on the side of the coating sheet 510. Also, the decorative sheet 520 may be in a sandwich mode in which a metal film is laminated on both sides of the substrate.
More specifically, the decorative sheet 520 is an aluminum glass cloth (ALGC) in which an aluminum foil and a glass cloth are laminated, an aluminum kraft (ALK) in which an aluminum foil and a kraft paper are laminated, and an aluminum foil and a split cloth. And aluminum laminated cloth (ALW) laminated together.

  The surface of the decorative sheet 520 is covered with a restraining member 530. By this, the heat insulation fiber layer 400, the coating layer 510, and the decorative sheet 520 laminated | stacked on the resin piping 200 can be restrained stably. The restraint member 530 can also prevent peeling of the decorative sheet 520. The restraint member 530 may be made of resin or metal, but is preferably made of metal from the viewpoint of fire resistance. The constraining member 530 is not particularly limited as long as it restrains the heat insulating fiber layer 400 and the decorative sheet 520 and can protect the surface of the decorative sheet, but in the present embodiment, a reticulated sheet is used.

[Construction]
The heat insulation piping system 100 may be constructed as follows.
The resin piping 200 is appropriately connected by a joint and fixed to a fixed base at an appropriate position. The heat insulating fiber layer 400 is coated on the outer peripheral surface of the resin pipe 200. The heat insulation fiber layer 400 can be sheathed in the resin piping 200 using the heat insulation fiber molding which is cut into a predetermined length and formed into an annular shape and in which a cut is formed in the axial direction.

After the heat insulating fiber layer 400 is covered with the resin pipe 200, the surface of the heat insulating fiber layer 400 is integrally covered with the covering layer 510. The covering layer 510 can be wound on the surface to be covered, for example, while taking out the sheet from a roll wound with a long sheet of resin sheet. In particular, the resin sheet is wound so as to completely shield the joint S of the heat insulating fiber layer 400.
After the covering layer 510 is provided, the decorative sheet 520 is overlaid and wound on the entire surface of the covering layer 510, and then the constraining member 530 is wound.

[Other embodiments]
Hereinafter, the second embodiment in which the aspect of the heat insulating fiber layer is different, and the third embodiment in which the aspect of the resin piping is different will be described. In these other embodiments, fundamentally differences from the first embodiment will be described, and description of the same points will be omitted.

Second Embodiment
FIG. 3 is a schematic cross-sectional view and a partially enlarged view of the heat insulating piping system of the second embodiment, and corresponds to FIG. 2 of the first embodiment. The heat insulation piping system 100a shown in FIG. 3 includes a resin pipe 200, a heat insulation fiber layer 400a, and a covering layer 510. Although not shown, the decorative sheet 520 and the restraining member 530 can be further included as in the first embodiment.

[Adiabatic fiber layer 400a]
The heat insulation fiber layer 400a includes a skin layer 410 located on the resin pipe 200 side, a plurality of thin layers 430, and a heat insulation layer 420 filling the space therebetween. The thin layer 430 is formed substantially concentrically with the skin layer 410. The thin layer 430, like the skin layer 410, is configured to have a smaller specific surface area than the heat insulating layer 420. By this, in the inside of the heat insulation fiber layer 400a, since many layers (thin layers 430) having a small specific surface area exist in the radial direction, it is difficult for the air to permeate in the radial direction. Therefore, the progress of condensation on the outer surface of the resin pipe 200 can be further favorably suppressed.

  The thin layer 430 is embodied by making the fiber density higher than the heat insulating layer 420, containing the binder resin, or making the fiber density higher than the heat insulating layer 420 and containing the binder resin.

When the fiber density of the thin layer 430 is larger than the fiber density of the heat insulating layer 420, the average density of the heat insulating fiber layer 400a is preferably higher. In this case, for example, it may be 1.1 times or more and 3 times or less the average density of the heat insulation fiber layer 400a, or 22 kg / m ³ or more and 300 kg / m ³ or less, preferably 26 kg ³ or more and 300 kg / m ³ or less, More preferably, it may be 50 kg / m ³ or more and 300 kg / m ³ or less. More preferably, the thin layer 430 is configured to have a small specific surface area to the extent that air can not permeate. This makes it more difficult for air to permeate in the radial direction. Therefore, the progress of condensation on the outer surface of the resin pipe 200 can be further favorably suppressed.

  When the thin layer 430 contains a binder resin, the binder resin coats the surface of the fibers, whereby the binder resin intervenes between the fibers. Therefore, the specific surface area is reduced by narrowing the distance between the fibers. Alternatively, the binder resin stably maintains a relatively high fiber density in the thin layer 430 by fixing the state in which the fibers are compressed and the specific surface area is reduced. The binder resin is not particularly limited, and examples thereof include thermosetting resins such as phenol resins.

  The thickness of the thin layer 430 may be, for example, 0.3 mm or more and 7 mm. Being 0.3 mm or more is preferable in that the inside of the heat insulation fiber layer 400a can be sufficiently divided, and being 7 mm or less is preferable in keeping the heat insulation performance as the whole heat insulation fiber layer 400a. The thickness of the thin layer 430 is more preferably 0.5 mm or more and 6 mm or less, and still more preferably 1 mm or more and 5 mm or less from the viewpoint of making it difficult to allow air to permeate in the radial direction.

[Production of heat insulation fiber layer]
The heat insulation fiber layers 400 and 400a can be manufactured, for example, as follows. First, glass wool is hot-pressed to form a sheet (step 1). Then, a glass wool sheet is concentrically stacked in layers (preferably, a long glass wool sheet is wound in layers) to form a thick tubular member (step 2). Further, the glass wool sheets overlapping each other are fixed (step 3). In the fixing of step 3, heat may be used for baking or bonding may be performed using a binder resin. When using binder resin, it is preferable that it is a water-resistant thing.

  The skin layer 410 can be formed by raising the heating temperature at the time of heat pressing and / or prolonging the heating time with respect to the portion of the innermost surface of the cylindrical member in step 2. In order to increase the thickness of these skin layers, the heating temperature may be adjusted by higher heating and / or longer heating time.

  The thin layer 430 may be created by increasing the heating temperature and / or heating time of the hot press of step 1; may be created by increasing the amount of binder resin in step 3; Two types of glass wool sheets with different heat press conditions in step 1 (that is, one glass wool sheet has a higher density) may be stacked and created by performing winding of step 2 in the stacked state Even if a glass wool sheet and a high density sheet of another material (a material that can be fixed to be adhered to glass, etc.) are laminated and created by performing step 2 winding in the superposed state You may make it by combining these methods arbitrarily.

Third Embodiment
FIG. 4 is a schematic cross-sectional view of resin piping in the heat insulation piping system of the third embodiment. As elements other than resin piping which constitutes the heat insulation piping system of a 3rd embodiment, an element in the above-mentioned 1st embodiment and a 2nd embodiment may be combined, without being limited in particular.

[Resin piping 200b]
The present embodiment is particularly useful when the resin pipe 200b shown in FIG. 4 is a pipe that allows both cold water and hot water to flow. In the resin pipe 200b, the first layer 210b, the second layer 220b, and the third layer 230b are stacked in this order in the direction from the axis O to the outer periphery. An adhesive layer or the like may or may not be interposed between the respective layers. In resin piping 200b, one or more other layers may be further laminated.

[First layer 210b, third layer 230b]
The first layer 210b and the third layer 230b do not contain fibers as in the second layer 220b described later. The inner layer 210b coats the inner circumferential surface of the second layer 220b so that the fibers contained in the second layer 220b are not mixed in the fluid flowing inside the resin pipe 200b. In addition, the third layer 230 b prevents the surface from being roughened so that the fibers contained in the second layer 220 b are not exposed to the outer peripheral surface of the resin pipe 200 b. As a result, the outer peripheral surface of the resin pipe 200b becomes smooth, so the skin layer 410 of the heat insulating fiber layer 400 (see FIG. 2 of the first embodiment and FIG. 3 of the second embodiment) and the outer peripheral surface of the resin pipe 200b. The contact is improved, the air contacting the outer peripheral surface of the resin pipe 200b is reduced, and the occurrence of condensation can be suppressed.

  The thickness of the first layer 210b and the third layer 230b may be 0.5 mm or more. By this, good surface smoothness and impact resistance performance can be obtained. Although the upper limit in the range of the thickness of the first layer and the third layer is not particularly limited, it is, for example, 10 mm in consideration of coexistence with dimensional stability.

  Each of the first layer 210b and the third layer 230b is made of a thermoplastic resin. As a result, mechanical characteristics are uniform on both surfaces of the second layer 220b, and the manufacturing efficiency of the resin pipe 200b is also good. The thermoplastic resins constituting the first layer 210b and the third layer 230b may be polyolefin resins. As polyolefin resin, what was illustrated above as resin which constitutes resin piping 200 of a 1st embodiment can be used without limiting in particular. The thermoplastic resin constituting the first layer 210b and the thermoplastic resin constituting the third layer 230b may be the same or different.

[The second layer 220b]
The second layer 220 b is made of a fiber reinforced resin containing fibers in a thermoplastic resin which is a matrix resin. Resin piping inherently has a large linear expansion coefficient compared to metal piping, so heat expansion and contraction due to the flow of cold water in the piping is large, but because the second layer 220b is a resin containing fibers, resin piping The thermal expansion and contraction of 200b is suppressed, and excellent dimensional stability is obtained. Therefore, even when cold / hot water flows into the resin pipe 200b, the gap or distortion at the joint S (see FIG. 1) of the heat insulating fiber layer 400 can be preferably prevented. For this reason, the stable thermal insulation effect can be acquired in a wide temperature range.

(Material of Second Layer 220b-Matrix Resin)
The matrix resin in the second layer 220b is a thermoplastic resin, preferably a polyolefin resin. As polyolefin resin, resin similar to resin which constitutes the 1st layer 210b and the 3rd layer 230b may be used. More preferably, the matrix resin of the second layer 220b is the same as the resin constituting the first layer 210b and the third layer 230b. As a result, the adjacent layers easily conform to each other, and interfacial peeling can be effectively suppressed.

(Material of Second Layer 220b-Fiber)
As materials of fibers contained in the second layer 220b, inorganic fibers such as glass fibers, carbon fibers, ceramic fibers and boron fibers; metal fibers; and aramid, polyester, polyethylene, polyamide, vinylon, polyacetal, polyparaphenylene benzoxazole And organic fibers such as high strength polypropylene. Examples of carbon fibers include PAN (polyacrylonitrile) carbon fibers, silicon-titanium-carbon fibers, pitch carbon fibers and the like. Moreover, as an organic fiber, natural fibers, such as kenaf and hemp, are also mentioned. In the present invention, the fiber is preferably glass fiber from the viewpoint of low linear expansion (low heat stretchability). The above fibers can be used alone or in combination of two or more.
Further, as a method of holding the matrix resin in such fibers, all known methods can be adopted.

  The fibers contained in the second layer 220b may be surface-treated. For example, when the fiber is glass fiber, examples of the surface treatment agent include methacrylic silane, acrylic silane, aminosilane, imidazole silane, vinyl silane and epoxy silane. Among these, aminosilane is preferable.

  As an embodiment in which these fibers are arranged, an embodiment in which continuous fibers are arranged in the longitudinal direction, an embodiment in which the continuous fibers arranged in the longitudinal direction and continuous fibers intersecting with the continuous fibers are arranged, and a finite length The aspect by which the fiber of these is distribute | arranged is mentioned.

  The fiber length of the fibers contained in the second layer 220b is shorter than the fiber length of the fibers constituting the heat insulation fiber layers 400 and 400a (see FIG. 2 of the first embodiment and FIG. 3 of the second embodiment). As a result, the formability is good and the orientation of the fibers can be easily controlled. Preferably, the fiber length of the fibers contained in the second layer 220b is 5 mm or less. By setting the fiber length of the fiber within this range, the strength, rigidity, dimensional stability and elongation at high temperature of the molded body are effectively increased. The fiber length of the fiber is preferably 3 mm or less, preferably 1 mm or less, from the viewpoint of more effectively enhancing the strength, rigidity, dimensional stability and elongation at high temperature of the molded body. The lower limit value included in the above fiber length range is not particularly limited, but may be, for example, 0.05 mm, preferably 0.1 mm from the viewpoint of strength and rigidity. The fiber length is an average of the lengths of fibers contained in the second layer 220b.

  The fiber diameter of the fibers contained in the second layer 220b is larger than the fiber diameter of the fibers constituting the heat insulation fiber layers 400 and 400a (see FIG. 2 of the first embodiment and FIG. 3 of the second embodiment). This can provide the desired strength and stiffness. Preferably, the fiber diameter of the fibers contained in the second layer 220b may be 5 μm to 50 μm, more preferably 12 μm to 50 μm. By setting the fiber diameter of the fiber within this range, the strength, rigidity, dimensional stability and elongation at high temperature of the molded body are effectively increased. The fiber diameter of the fibers may be preferably 10 μm to 20 μm, more preferably 12 μm to 14 μm from the viewpoint of more effectively enhancing the strength, rigidity, dimensional stability and elongation at high temperature of the molded body . The fiber diameter is an average of the maximum diameters of the cross sections of the fibers contained in the second layer 220b.

  The amount of fibers contained in the second layer 220b is 10% by weight or more and less than 60% by weight based on 100% by weight of the entire resin composition for producing the second layer 220b. By setting the amount of fibers to the above lower limit value or more, good dimensional stability of the resin piping 200b can be obtained. By setting the amount of fibers to the upper limit value or less, good moldability can be obtained, and furthermore, the fracture mode of the second layer 220b can be easily transitioned to ductile fracture. Therefore, brittle fracture of the second layer 220b can be less likely to occur.

(Material of second layer-polyolefin binder)
Furthermore, the fibers may be converged with a polyolefin binder. The polyolefin sizing agent is not particularly limited as long as glass fibers can be converged, but is specifically a polyolefin. The polyolefin may be similar to the matrix resin. That is, if the matrix resin is polyethylene, the focusing agent may also be polyethylene. Furthermore, the said polyolefin as a convergence agent contains modified polyolefin. Specific examples of the polyolefin binder include maleic acid-modified polyolefin and silane-modified polyolefin. From the viewpoint of providing the second layer 220b with a low linear expansion coefficient, the polyolefin binder is preferably a silane-modified polyolefin, and more preferably the fiber is glass fiber.

From the viewpoint of causing the fibers to converge well, the density of the polyolefin binder is preferably 0.85 g / cm ³ or more, and preferably 1.1 g / cm ³ or less.
From the viewpoint of causing the fibers to converge well, the MFR (melt mass flow rate) of the polyolefin sizing agent is preferably 0.01 g / 10 min or more, preferably 16 g / 10 min or less. The MFR is a value measured under the conditions of a temperature of 190 ° C. and a load of 2.16 kgf based on JIS K7210.

  Any method may be used to cause the fibers to converge with the polyolefin binder. The amount of fibers is preferably 6 parts by weight or more, more preferably 12 parts by weight or more, still more preferably 19 parts by weight or more, preferably 533 parts by weight or less, based on 100 parts by weight of the matrix resin and the polyolefin binder. Is 171 parts by weight or less, more preferably 138 parts by weight or less. By setting the amount of fibers in the above range, the strength, dimensional stability and elongation at high temperature of the molded article are effectively increased.

(Material of second layer-compatibilizer)
Furthermore, the second layer 220b may contain a compatibilizer. Examples of the compatibilizer include modified polyolefins and chlorinated polyolefins. Examples of modified polyolefins include maleic acid-modified polyolefins and silane-modified polyolefins. One type of compatibilizer may be used alone, or two or more types may be used in combination. From the viewpoint of providing the second layer 220b with a low linear expansion coefficient, the compatibilizer is preferably a silane-modified polyolefin, and more preferably, the fiber is glass fiber.

  In addition, the modified polyolefin as a compatibilizer is distinguished from the above-mentioned modified polyolefin as a convergence agent. The amount of the compatibilizer contained in the second layer 220b is 0.5% by weight or more and 20% by weight or less, preferably 1% by weight or more, based on 100% by weight of the entire resin composition for producing the second layer 220b. It is 10% by weight or less. By setting the content of the compatibilizer in such a range, the strength, dimensional stability and elongation at high temperature of the molded body are effectively increased. The amount of the compatibilizer contained in the second layer 220b is preferably 2% by weight or more and 10% by weight or less, from the viewpoint of more effectively enhancing the strength, dimensional stability and high temperature elongation of the molded body. Preferably it is 2 to 9 weight%.

[Layer thickness ratio]
When the relative thickness of the first layer 210b is 1, the ratio of each layer of the resin piping 200b is 2 to 6, preferably 3 to 5, and the relative thickness of the third layer 230b is 0. It is preferable that it is five or more and two or less. By setting the thickness of each layer to such a ratio, it is possible to obtain good surface smoothness by the first layer 210b and the third layer 230b and also obtain good dimensional stability by the second layer 220b.

[Manufacturing]
The resin pipe 200b prepares a resin composition for producing the first layer 210b and the third layer 230b and a resin composition for producing the second layer 220b, and forms the resin composition using a molding machine. The molding machine is not particularly limited, and examples thereof include a single-screw extruder, a twin-screw different-direction parallel extruder, a two-screw different-direction conical extruder, and a two-screw same-direction extruder. Furthermore, in the case of molding using a molding machine, the mold to be shaped, the temperature of the resin, etc. are not particularly limited.

Modified Example of Third Embodiment
Hereinafter, modifications in which the aspect of the boundary of each layer of resin piping is different will be described. In these modifications, basically the points different from the third embodiment will be described, and the description of the same points will be omitted.

First Modification
FIG. 5 is a schematic cross-sectional view of a first modification of resin piping in the heat insulating piping system of the third embodiment, and corresponds to FIG. 4 of the third embodiment. FIG. 6 is a partially enlarged view of FIG.

  In the resin pipe 200c shown in FIG. 5, the first layer 210c, the second layer 220c, and the third layer 230c are stacked in this order and in contact with each other in the direction from the axis O to the outer periphery. In this modification, although what has resin piping 200c comprised from three layers is mentioned, this invention does not exclude that resin piping 200c further has one or more other layers.

(Interface roughness)
In the resin pipe 200c, the interface 225c between the second layer 220c and the third layer 230c is roughened. Specifically, the ten-point average roughness Rz (in accordance with JIS B 0601) of the interface 225c is 30 μm or more, preferably 50 μm or more. Furthermore, the interface maximum height Ry (in accordance with JIS B 0601) of the interface 225c is 50 μm or more, preferably 100 μm or more. Thus, even if resin pipe 200c receives at least one of deformation due to external load and deformation due to environmental change such as temperature change, humidity change, and aging deterioration, the second layer 220c and the third layer It is hard to cause interface exfoliation with 230c.

The upper limit of the ten-point average roughness Rz of the interface 225c is, for example, 300 μm, preferably 200 μm. The upper limit of the interface maximum height Ry of the interface 225c is, for example, 500 μm, preferably 300 μm. This makes it easy to secure manufacturability and the like.
In FIG. 6, a surface serving as a reference of the ten-point average roughness Rz and the interface maximum height Ry is shown as an average surface 225V.

(Linear expansion performance)
The resin pipe 200c is configured such that the linear expansion coefficient of the second layer 220c is smaller than the linear expansion coefficient of the first layer 210c and the third layer 230c. Specifically, the linear expansion coefficient of the second layer 220c may be 0.8 times or less or 0.3 times or less the linear expansion coefficient of the first layer 210c and the third layer 230c. More specifically, if the linear expansion coefficient of the first layer 210c and the third layer 230c is, for example, 12 × 10 ⁻⁵ or more and 14 × 10 ⁻⁵ or less, the linear expansion coefficient of the second layer 220 c is 10 × 10 ⁻ It may be around ⁵ (9.6 × 10 ⁻⁵ or more and 11.2 × 10 ⁻⁵ or less).

  The linear expansion coefficient of the resin pipe 200c can be determined by the following method. The tube molded body is cut into an arbitrary length and aged for 2 hours or more (for example, 24 hours) in a thermostatic bath set to an arbitrary temperature (Thot). After curing, the length of the tube is measured (Lhot). Thereafter, the same formed tube is cured for 2 hours or more (for example, 24 hours) in a thermostat set at an arbitrary temperature (Tcool) lower than Thot, and the length of the formed tube is measured (Lcool). The obtained value is substituted into the following equation 1 to determine the linear expansion coefficient.

  In the resin pipe 200c, since the interface 225c is sufficiently rough, the linear expansion coefficient of the second layer 220c is smaller than that of the first layer 210c and the third layer 230c by 0.8 times or less. Since the first layer 210c and the third layer 230c, which have larger linear expansion coefficients, preferably follow the two-layer 220c, it is possible to obtain excellent releasability. The lower limit value included in the range of the linear expansion coefficient is not particularly limited, but is, for example, 0.01 times from the viewpoint of obtaining excellent hard peeling property.

(Hot internal pressure creep performance)
Resin piping 200c suppresses brittle fracture and does not generate a knee point (change point from ductile fracture to brittle fracture) in the hot internal pressure creep test at 80 ° C., or generation of knee point shifts to a longer side It is preferable to suppress the brittle fracture so that no knee point is generated.

The resin pipe 200c has high creep performance at high temperature, and has a wide application range as a pipe for flowing a high temperature fluid. The hot internal pressure creep test at 80 ° C. is tested at 80 ° C. using a hot internal pressure creep tester. The hot internal pressure creep tester includes a tester manufactured by Condo Science.
Specifically, with regard to the hot internal pressure creep performance at 80 ° C. of the multi-resin pipe 200c, the circumferential stress of 5.0 MPa is 1000 hours or more, preferably 5.1 MPa for 1000 hours or more, more preferably 5. It is 1000 hours or more at 2 MPa. The time in the above-mentioned hot internal pressure creep performance is the fracture time. It is preferable that the creep performance at high temperature of the multilayer tube is high. When the creep performance at high temperature of the multilayer pipe material is high, the application range as piping flowing high temperature fluid is expanded. Thus, the resin pipe 200c has long-term durability.

  The resin pipe 200c is particularly useful as a pipe for flowing cold water and hot water in order to achieve both the above-described linear expansion performance and the hot internal pressure creep performance.

(Layer thickness ratio)
When the relative thickness T1c (see FIG. 6) of the first layer 210c is 1 as in the third embodiment, the relative thickness T2c of the second layer 220c is preferably 2 or more and 6 or less, as in the third embodiment. The relative thickness T3c of the third layer 230c is preferably 0.5 or more and 2 or less. By setting the thickness of each layer to such a ratio, it is possible to obtain good surface smoothness by the first layer 210c and the third layer 230c, and to obtain good dimensional stability by the second layer 220c. The surface on the outer peripheral side serving as the reference of the relative thickness T2c of the second layer 220c and the surface on the axis O side serving as the reference for the relative thickness T3c of the third layer 230c are the average surface 225V.

  The resin piping 200c prepares a resin composition for producing the first layer 210c and the third layer 230c and a resin composition for producing the second layer 220c, and shapes the resin composition using a molding machine. The molding machine is not particularly limited, and examples thereof include a single-screw extruder, a twin-screw different-direction parallel extruder, a two-screw different-direction conical extruder, and a two-screw same-direction extruder. Furthermore, in the case of molding using a molding machine, the mold to be shaped, the temperature of the resin, etc. are not particularly limited.

  The extrusion speed of the resin composition layer constituting the second layer 220c and the extrusion speed of the resin composition layer constituting the third layer 230c are preferably different. This allows the interface 225c to be preferably roughened. In this case, the extrusion speed of the resin composition layer constituting the third layer 230c may be slower than the extrusion speed of the resin composition layer constituting the second layer 220c, so that distortion or the like hardly occurs in the resin piping 200c. It is more preferable in that it is compatible with mass production.

Second Modified Example
FIG. 7 is a schematic cross-sectional view of a second modification of resin piping in the heat insulation piping system of the third embodiment.
In the resin pipe 200d shown in FIG. 7, the first layer 210d, the second layer 220d, and the third layer 230c are stacked in order in the direction from the axis O to the outer periphery so as to be in contact with each other. The resin pipe 200d is roughened not only at the interface 225c between the second layer 220d and the third layer 230c but also at the interface 215d between the first layer 210d and the second layer 220d in the same manner as the interface 225c. The specific interface roughness of interface 215d is similar to interface 225c.

  In the production of the resin pipe 200d, the extrusion speed of the resin composition layer constituting the first layer 210d and the extrusion speed of the resin composition layer constituting the second layer 220d are made different, and the second layer 220d is constituted. It is preferable to make the extrusion rate of the resin composition layer different from the extrusion rate of the resin composition layer that constitutes the third layer 230c. This allows the interface 215d and the interface 225c to be preferably roughened. In this case, the extrusion speed of the resin composition layer constituting the second layer 220d is slower than the extrusion speed of the resin composition layer constituting the first layer 210d, and the resin composition layer constituting the second layer 220d is It is more preferable that the extrusion speed of the resin composition layer constituting the third layer 230c be slower than the extrusion speed, since distortion and the like are less likely to occur in the resin pipe 200d, and the affinity for mass production is obtained.

  In the present invention, in addition to the first and second modifications described above, the first layer of the interface between the first layer and the second layer and the interface between the second layer and the third layer The embodiment in which the interface between the second layer and the second layer is roughened is also included.

Example 1
The heat insulation piping system which combined the heat insulation piping system 100 shown in FIG. 2 and the resin piping 200b shown in FIG. 4 was created. That is, the heat insulation piping system by which resin piping 200b was covered with the heat insulation fiber layer 400 and the coating layer 510 was created.

The resin piping 200b is made of polyethylene (density 0.948 g / cm ³ , MFR 0.05 g / 10 min) to produce the first layer 210 b and the third layer 230 b, and polyethylene (density 0) to produce the second layer 220 b. Resin composition containing 20% by weight of glass fiber (fiber length 3 mm, fiber diameter 13 μm) and 3% by weight compatibilizer (silane-modified polyethylene) as matrix resin with 948 g / cm ³ , MFR 0.05 g / 10 min) And molded by coextrusion. The three layers were extruded using separate single extruders. A 40 mm for the first and third layers and a 75 mm single extruder for the second layer were used. The extrusion temperature was 200 ° C., and the mold used was a dedicated three-layer mold. The internal diameter of the obtained resin piping 200b was 51 mm, and the external diameter was 63 mm.

The linear expansion coefficient of the resin pipe was determined as follows. The resin piping was cut into a length of 1000 mm and aged for 24 hours in a thermostatic bath set at 60 ° C. (Thot). After curing, the length of the multilayer piping (Lhot) was measured. Thereafter, the same multilayer pipe was aged for 24 hours in a thermostatic bath set at 5 ° C. (Tcool), and the length (Lcool) of the multilayer pipe was measured. The obtained value was substituted into the following equation 1 to determine the linear expansion coefficient. As a result, the linear expansion coefficient of the resin pipe 200 b was 5 × 10 ⁻⁵ / ° C.

The outer surface of the resin pipe 200b was coated with glass wool, which is the heat insulating fiber layer 400, in a 23 ° C. (normal temperature) environment. The average density of the glass wool was 45 kg / m ³ , and the skin layer 410 was 66 kg / m ³ (average density within the thickness range of 5 mm from the innermost circumference of the glass wool). The surface of the glass wool was roll coated (thickness 60 μm) with a low density polyethylene film which is a coating layer 510.

(Test 1)
Cold water (5 ° C.) and warm water (50 ° C.) were alternately flowed 100 cycles at intervals of 10 minutes into the interior of the resin piping 200 b using the heat insulation piping system created as described above. During this time, it was confirmed that no deviation occurred in the glass wool.

(Test 2)
It exposed to the environment of 30 degreeC of external temperature, and the environment of 80% of humidity for 3 days, flowing cold water (5 degreeC) inside the resin piping 200b using the heat insulation piping system created as mentioned above. The weight before pouring cold water and the weight after pouring cold water under the above environment for 3 days were measured. If the weight difference between the two is within 1 g, it can be determined that there is no substantial change in weight, that is, good heat insulation is present. In the present example, the increase was only 0.2 g, and good heat insulation was confirmed.

Comparative Example 1
An adiabatic piping system was created in the same manner as in Example 1 except that the skin layer 410 was not provided. When Test 2 of Example 1 was performed, dew condensation on the surface of the resin piping 200b was confirmed.

  Although the preferred embodiments of the present invention are as described above, the present invention is not limited to them alone, and various other embodiments can be made without departing from the spirit of the present invention.

[Correspondence between each part in the embodiment and each component of the claims]
The heat insulation piping system 100, 100a in the present specification corresponds to "insulation pipe system" in the claims, the resin piping 200, 200b, 200c, 200d corresponds to "resin piping", and the first layers 210b, 210c, 210d The second layers 220b, 220c and 220d correspond to the "second layer", the third layers 230b and 230c correspond to the "third layer", and the heat insulating fiber layers 400 and 400a correspond to the "first layer". The skin layer 410 corresponds to the "skin layer", the thin layer 430 corresponds to the "annular thin layer", and the covering layer 510 corresponds to the "coating layer".

100, 100a heat insulation piping system 200, 200b, 200c, 200d resin piping 210b, 210c, 210d first layer 220b, 220c, 220d second layer 230b, 230c third layer 400, 400a insulation fiber layer 410 skin layer 430 thin layer ( Annular thin layer)
510 Coating layer

Claims (6)

A resin pipe, a heat insulating fiber layer covering the outer peripheral surface of the resin pipe, and a cover layer covering the outer peripheral surface of the heat insulating fiber layer,
The heat insulation fiber layer is made of glass fiber including a skin layer on the surface on the side of the resin pipe ,
The resin pipe is a multilayer pipe including a first layer, a second layer, and a third layer in the direction from the axial center to the outer periphery,
The first layer is a thermoplastic resin, the second layer is a thermoplastic resin containing glass fibers, the third layer is a thermoplastic resin, and the content of the fibers in the second layer is the second 10% by weight or more and 60% by weight or less, where the total weight of the resin composition for producing the layer is 100% by weight,
The fiber diameter of the fibers contained in the second layer is larger than the fiber diameter of the fibers constituting the heat insulating fiber layer, and the fiber length of the glass fibers constituting the heat insulating fiber layer is the second layer The fiber length of the glass fiber contained in is smaller,
Thermal insulation piping system. The heat insulation piping system according to claim 1, wherein an average density of the heat insulation fiber layer is 20 kg / m ³ or more and 100 kg / m ³ or less.   The heat insulation piping system according to claim 2, wherein the heat insulation fiber layer substantially concentrically includes a plurality of thin tubular layers having a density higher than the average density. The fiber diameter of the fibers constituting the heat insulation fiber layer is 5 μm or more and 10 μm or less,
The heat insulation piping system according to any one of claims 1 to 3, wherein a fiber diameter of the fibers contained in the second layer is 12 μm or more and 50 μm or less. The heat insulation according to any one of claims 1 to 4 , wherein the fiber length of the fibers constituting the heat insulation fiber layer is more than 5 mm, and the fiber length of the fibers contained in the second layer is 5 mm or less. Piping system. If set to 1 the relative thickness of the first layer, the relative thickness of the second layer is from 2 to 6, the relative thickness of the third layer is 0.5 to 2, claims 1 to 5 The heat insulation piping system according to any one of the above.

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