Polyurethane thermal insulation pipe with multi-layer composite cavity structure

Abstract

The utility model discloses a polyurethane thermal insulation pipe with a multi-layer composite cavity structure, which belongs to the technical field of thermal insulation pipes, and comprises an inner-layer steel pipe for bearing flowing liquid, an inner wall layer for improving thermal insulation effect is attached to the outer part of the inner-layer steel pipe in a heat-sealing manner, and the outer part of the inner-layer steel pipe is provided with an outer wall layer for improving thermal insulation effect. A cavity layer group for slowing down the heat flow rate is attached to the outer part of the inner wall layer in a heat-sealing manner, and an outer wall layer is attached to the outer part of the cavity layer group in a heat-sealing manner; the inner wall layer is made of a polyurethane foam material, the thickness of the inner wall layer is 2-5 mm, and the thermal conductivity of the polyurethane foam material ranges from 0.018 W / (m.K) to 0.033 W / (m.K); the outer wall layer is made of a high-density polyethylene material, and the thickness of the outer wall layer is 2-4 mm; and by reasonably configuring the cavity layer group structures with different thermal conductivities, heat transfer and loss can be effectively reduced, and the overall energy-saving effect of the thermal insulation pipe is improved.

Description

Technical Field

[0001] This utility model relates to the field of thermal insulation pipe technology, specifically a polyurethane thermal insulation pipe with a multi-layer composite cavity structure. Background Technology

[0002] Insulated pipes are used to reduce the temperature difference between the inside and outside of pipelines and are widely used in liquid and gas transmission networks, centralized heating, refrigeration, petroleum, chemical and other industries. The main function of insulated pipes is to reduce the loss of heat or cold through insulation materials, thereby improving the energy efficiency and operating efficiency of the system.

[0003] For example, patent CN206409822U discloses an insulated pipe, including an inner pipe, an insulation layer on the outside of the inner pipe, a metal outer pipe sleeved on the outside of the insulation layer, a chlorosulfonated polyethylene anti-corrosion paint layer on the outside of the metal outer pipe, and a polytetrafluoroethylene film covering the chlorosulfonated polyethylene anti-corrosion paint layer. Because the chlorosulfonated polyethylene anti-corrosion paint layer has good resistance to atmosphere, moisture, salt, alkali, acid, oxidants, and petroleum, it has excellent outdoor weather resistance, a tough coating, excellent wear resistance and stability, and strong adhesion, thus greatly improving the corrosion resistance of the insulated pipe. Furthermore, the chlorosulfonation... The polyethylene anti-corrosion paint layer is also elastic, which can effectively improve the overall toughness of the insulation pipe and reduce the possibility of breakage. Some existing composite insulation pipes adopt a multi-layer structure design. Different materials have different thermal conductivity. The materials, combination and arrangement, and material thickness of the composite pipe directly affect the overall insulation effect. For example, placing high thermal conductivity materials in the inner layer, low thermal conductivity materials in the outer layer, and adding a reflective layer or other heat insulation materials in the middle can further reduce the heat flux density. However, some existing insulation pipes have unreasonable material distribution, insufficient insulation performance, and serious heat loss.

[0004] To address the aforementioned issues, innovative designs are urgently needed based on existing insulation pipes. Utility Model Content

[0005] The purpose of this invention is to provide a polyurethane insulation pipe with a multi-layer composite cavity structure to solve the problems mentioned in the background art, such as unreasonable distribution of constituent materials, insufficient insulation performance, and serious heat loss in some existing insulation pipes.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a multi-layer composite cavity structure polyurethane insulation pipe, comprising an inner steel pipe that carries the liquid flowing through it, an inner wall layer that enhances the insulation effect is heat-sealed and bonded to the outside of the inner steel pipe, and a cavity layer assembly that slows down the heat flow rate is heat-sealed and bonded to the outside of the inner wall layer, and an outer wall layer is heat-sealed and bonded to the outside of the cavity layer assembly; the inner wall layer is made of polyurethane foam material with a thickness of 2-5mm, and the thermal conductivity of the polyurethane foam material is between 0.018W / (m·K) and 0.033W / (m·K); the outer wall layer is made of high-density polyethylene material with a thickness of 2-4mm.

[0007] Preferably, the cavity layer group includes a first cavity layer disposed outside the inner wall layer, a second cavity layer disposed outside the first cavity layer, and a third cavity layer disposed outside the second cavity layer.

[0008] Preferably, the first cavity is filled with polystyrene foam material with a thickness of 10-20 mm and the thermal conductivity of the polystyrene foam material is between 0.035-0.042 W / (m·K).

[0009] Preferably, the second cavity-filling gel material has a thickness of 5-15 mm and a thermal conductivity of 0.012-0.016 W / (m·K).

[0010] Preferably, the third cavity is a vacuum layer with a thickness of 1-5 mm and a thermal conductivity range of 0.002-0.0046 W / (m·K).

[0011] Preferably, a gas leakage prevention sealing mechanism is provided between the third cavity and the outer wall layer.

[0012] Preferably, the sealing mechanism includes a foam ring fitted in the third cavity, and multiple foam strips are fixed at equal angles between adjacent foam rings; the inner and outer sides of the foam ring and foam strips are respectively in contact with the second cavity filler and the outer wall surface.

[0013] Preferably, the inner side of the outer wall layer has multiple longitudinally spaced grooves, and heat-sealing rings are fitted into the grooves; the positions of the heat-sealing rings correspond to the positions of the foam rings, and the heat-sealing rings are bonded and fixed between the foam rings and the outer wall layer by heat.

[0014] Compared with the prior art, the beneficial effects of this utility model are: the polyurethane insulation pipe with multi-layer composite cavity structure has a multi-layer structure, namely an inner steel pipe, an inner wall layer, a cavity layer group and an outer wall layer. The inner wall layer can improve the insulation effect and increase the mechanical strength of the pipe, while the outer wall layer provides external protection, strength and wear resistance of the pipe.

[0015] Furthermore, the cavity layer assembly consists of a first cavity, a second cavity, and a third cavity. The thermal conductivity of the third cavity is lower than that of the first cavity. This allows the first cavity material within the insulation pipe to achieve higher heat resistance and less deformation while reducing heat loss. The low thermal conductivity of the third cavity further reduces heat transfer, and the second cavity, positioned between the third and first cavities, also provides good insulation, further reducing heat flux density. By rationally distributing the materials within the insulation pipe, heat loss can be effectively mitigated, improving the insulation performance and thus reducing energy consumption, achieving energy-saving effects.

[0016] The first cavity is filled with polystyrene foam to increase the resistance to heat conduction and reduce heat loss. The second cavity is filled with gel material to further improve the thermal insulation effect and reduce temperature loss. The third cavity is a vacuum layer. Through the reasonable combination of these three layers, the thermal insulation effect is effectively enhanced, thereby effectively improving the thermal insulation performance and thus effectively reducing heat loss.

[0017] Furthermore, a sealing mechanism is provided in the third cavity, which is a vacuum layer. The sealing performance of the vacuum layer affects the vacuum insulation effect.

[0018] The foam rings and foam strips in the sealing mechanism are embedded inside the vacuum layer, dividing the vacuum layer into multiple sealed spaces. A heat-sealing ring is set between the foam ring and the outer wall layer. The heat-sealing ring can improve the sealing of the vacuum space between two adjacent foam rings, prevent gas leakage between the layers of the insulation pipe, and thus improve the insulation performance and energy-saving effect of the insulation pipe. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the three-dimensional structure of the outer wall layer of this utility model.

[0020] Figure 2 This is a schematic diagram of the cross-sectional structure of the inner wall layer of this utility model.

[0021] Figure 3 This is a schematic diagram of the cross-sectional structure of the first cavity layer of this utility model.

[0022] Figure 4 This is a schematic diagram of the three-dimensional structure of the foam ring of this utility model.

[0023] Figure 5 This is a schematic diagram of the three-dimensional structure of the heat-sealing ring of this utility model.

[0024] Figure 6 This is a schematic diagram of the three-dimensional structure of the embedded groove of this utility model.

[0025] In the diagram: 1. Inner steel pipe; 2. Inner wall layer; 3. First cavity layer; 4. Second cavity layer; 5. Third cavity layer; 6. Outer wall layer; 7. Foam ring; 8. Foam strip; 9. Embedded groove; 10. Heat sealing ring. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0027] Example 1: Please refer to Figures 1-6 The present invention provides the following technical solution: a polyurethane insulation pipe with a multi-layer composite cavity structure, comprising an inner steel pipe 1 that carries the liquid flowing through it, an inner wall layer 2 that enhances the insulation effect and is heat-sealed to the outside of the inner steel pipe 1, and a cavity layer group that slows down the heat flow rate and is heat-sealed to the outside of the inner wall layer 2, and an outer wall layer 6 that is heat-sealed to the outside of the cavity layer group; the inner wall layer 2 is made of polyurethane foam material with a thickness of 2-5mm, and the thermal conductivity of the polyurethane foam material is between 0.018W / (m·K) and 0.033W / (m·K); the outer wall layer 6 is made of high-density polyethylene material with a thickness of 2-4mm.

[0028] The cavity layer group includes a first cavity 3 disposed outside the inner wall layer 2, a second cavity 4 disposed outside the first cavity 3, and a third cavity 5 disposed outside the second cavity 4.

[0029] The first cavity 3 is filled with polystyrene foam, with a thickness of 10-20 mm. The thermal conductivity of the polystyrene foam ranges from 0.035 to 0.042 W / (m·K). The thermal stability of the polystyrene foam is 95℃ for short periods and 80-85℃ for long periods. Its placement in the innermost layer of the insulation pipe prevents physical deformation of the first cavity 3 under high-temperature conditions, maintaining stable insulation performance. The density of the polystyrene foam ranges from 15-32 kg / m³. 3 The compressive strength of polystyrene foam is typically between 100-350 kPa, which improves the structural strength and load-bearing capacity of the first cavity 3 filled with polystyrene foam. Furthermore, it effectively resists external pressure and mechanical impact, maintaining its shape and functional stability. Its water absorption rate is generally less than 1.0%, effectively preventing physical expansion or deformation caused by water absorption, ensuring the stability of the insulation performance of the insulated pipe during long-term use.

[0030] The second cavity 4 is filled with a gel material with a thickness of 5-15 mm. The thermal conductivity of the gel material ranges from 0.012 to 0.016 W / (m·K). By filling the second cavity 4 with gel material, the overall thermal insulation effect of the insulation pipe can be further improved, thereby further reducing heat loss and improving the insulation performance. In one possible embodiment, the gel material can be aerogel. Aerogel not only has low thermal conductivity but also possesses waterproof and fireproof properties. Under high-temperature conditions, the thermal conductivity of aerogel changes little, exhibiting excellent stability. Aerogel is also used in composite materials to further improve their insulation performance; for example, the thermal conductivity of composite materials doped with silicon aerogel can be as low as 0.0173 W / (m·K).

[0031] The third cavity 5 is a vacuum layer with a thickness of 1-5 mm. The thermal conductivity of the vacuum layer is between 0.002-0.0046 W / (m·K). Since the vacuum layer has almost no gas medium, it can effectively suppress heat convection and heat conduction, thereby reducing heat loss. Furthermore, the thermal conductivity of the vacuum layer will further decrease as the pressure decreases. For example, when the vacuum layer pressure drops to 0.1 Pa, the overall thermal conductivity can be less than 0.002 W / (m·K). Under high temperature conditions, the thermal conductivity of the vacuum layer may increase slightly, but it is still much lower than that of conventional insulation materials. For example, at 75 degrees Celsius, the thermal conductivity in a vacuum is about 0.00829 W / (m·K). The insulation pipe consists of a multi-layer structure, consisting of an inner steel pipe 1, an inner wall layer 2, a first cavity layer 3, a second cavity layer 4, a third cavity layer 5, and an outer wall layer 6, arranged sequentially from the inside out. The inner wall layer 2 is bonded to the polystyrene foam material filled in the first cavity layer 3 using adhesive. The polystyrene foam material filled in the first cavity layer 3 is bonded to the gel material filled in the second cavity layer 4 using adhesive. The second cavity layer 4 and the outer wall layer 6 are bonded to the foam rings 7 in the third cavity layer 5 using adhesive. The inner steel pipe 1 provides structural strength. Although the steel pipe has a high thermal conductivity, the inner wall layer 2, the cavity layer group, and the outer wall layer 6 are located outside the inner steel pipe 1, effectively mitigating heat loss.

[0032] Inner wall layer 2 is made of polyurethane foam material, with a rigid polyurethane foam density of 35-40 kg / m³. 3At this point, its thermal conductivity is only 0.018-0.023 W / (m·K), and its insulation effect is equivalent to that of a 40mm thick polystyrene board or a 380mm thick concrete, which can improve the insulation effect and increase the mechanical strength of the pipe; the first cavity 3 is filled with foamed polystyrene material, which has a micro-closed-cell structure and its thermal conductivity is usually between 0.035-0.042 W / (m·K), increasing the resistance to heat conduction and having good heat resistance to avoid high-temperature deformation; the second cavity 4 is filled with gel material, and the thermal conductivity of the gel material is between 0.012-0.016 W / (m·K). With a thermal conductivity between 0.002 and 0.0046 W / (m·K), aerogel exhibits excellent thermal insulation properties, effectively blocking heat transfer. The third cavity 5 is designed as a vacuum layer. Under vacuum conditions, the mean free path of gas molecules is much greater than the thickness of the vacuum layer, resulting in a gas thermal conductivity range between 0.002 and 0.0046 W / (m·K), effectively reducing heat loss. This multi-layer composite cavity structure of polyurethane insulation pipe, through the combination and composite design of different materials, has a reasonable distribution of materials between each layer. This arrangement can effectively slow down heat loss, improve the overall thermal insulation performance of the insulation pipe, and thus achieve energy-saving effects.

[0033] Example 2: Based on Example 1, a sealing mechanism is also disclosed, the specific structure of which is as follows: a sealing mechanism to prevent gas leakage is provided between the third cavity 5 and the outer wall layer 6; preferably, the sealing mechanism includes a foam ring 7 embedded in the third cavity 5, and multiple foam strips 8 are fixed at equal angles between adjacent foam rings 7; the inner and outer sides of the foam rings 7 and foam strips 8 are respectively in contact with the filling material of the second cavity 4 and the surface of the outer wall layer 6.

[0034] Multiple embedded grooves 9 are longitudinally and equally spaced on the inner side of the outer wall layer 6, and heat sealing rings 10 are fitted into the embedded grooves 9; the position of the heat sealing rings 10 corresponds to the position of the foam rings 7, and the heat sealing rings 10 are bonded and fixed between the foam rings 7 and the outer wall layer 6 by heat.

[0035] The third cavity 5 is set as a vacuum layer with extremely low thermal conductivity. The thermal conductivity of the vacuum layer is directly related to the vacuum's sealing performance. Multiple foam rings 7 are arranged longitudinally at equal intervals in the third cavity 5, forming a sealed space between adjacent foam rings 7. Multiple foam strips 8 are arranged at equal angles between adjacent foam rings 7. The foam strips 8 can further separate the vacuum space and improve the sealing performance of the vacuum layer. A heat sealing ring 10 is set between the foam rings 7 and the outer wall layer 6. The heat sealing ring 10 adheres to the foam rings 7 and the outer wall layer 6 when heated, which can further enhance the sealing performance of the vacuum layer and effectively prevent gas in the pipe wall from penetrating into the vacuum layer. This avoids the increase in thermal conductivity of the vacuum layer due to gas leakage, thus enabling the polyurethane insulation pipe with this multi-layer composite cavity structure to have a long-term energy-saving effect.

[0036] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0037] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polyurethane insulation pipe with a multi-layer composite cavity structure, comprising an inner steel pipe (1) that carries the liquid flowing through it, characterized in that: The inner steel pipe (1) is heat-sealed with an inner wall layer (2) to enhance the heat insulation effect, and the inner wall layer (2) is heat-sealed with a cavity layer group to slow down the heat flow rate, and the cavity layer group is heat-sealed with an outer wall layer (6). The inner wall layer (2) is made of polyurethane foam material with a thickness of 2-5 mm and a thermal conductivity of 0.018 W / (m·K)-0.033 W / (m·K). The outer wall layer (6) is made of high-density polyethylene material with a thickness of 2-4 mm.

2. The polyurethane insulation pipe with a multi-layer composite cavity structure according to claim 1, characterized in that: The cavity layer group includes a first cavity (3) disposed outside the inner wall layer (2), a second cavity (4) disposed outside the first cavity (3), and a third cavity (5) disposed outside the second cavity (4).

3. The polyurethane insulation pipe with a multi-layer composite cavity structure according to claim 2, characterized in that: The first cavity (3) is filled with polystyrene foam material with a thickness of 10-20 mm and a thermal conductivity of 0.035-0.042 W / (m·K).

4. The polyurethane insulation pipe with a multi-layer composite cavity structure according to claim 2, characterized in that: The second cavity (4) is filled with gel material with a thickness of 5-15 mm and a thermal conductivity of 0.012-0.016 W / (m·K).

5. The polyurethane insulation pipe with a multi-layer composite cavity structure according to claim 2, characterized in that: The third cavity (5) is a vacuum layer with a thickness of 1-5 mm and a thermal conductivity range of 0.002-0.0046 W / (m·K).

6. The polyurethane insulation pipe with a multi-layer composite cavity structure according to claim 2, characterized in that: A gas leakage prevention sealing mechanism is provided between the third cavity (5) and the outer wall layer (6).

7. The polyurethane insulation pipe with a multi-layer composite cavity structure according to claim 6, characterized in that: The sealing mechanism includes a foam ring (7) fitted in the third cavity (5), and multiple foam strips (8) are fixed at equal angles between adjacent foam rings (7); The inner and outer sides of the foam ring (7) and foam strip (8) are respectively attached to the filling material of the second cavity (4) and the surface of the outer wall layer (6).

8. The polyurethane insulation pipe with a multi-layer composite cavity structure according to claim 7, characterized in that: The outer wall layer (6) has multiple embedded grooves (9) spaced longitudinally on its inner side, and heat sealing rings (10) are fitted into the embedded grooves (9); The position of the heat-sealing ring (10) corresponds to the position of the foam ring (7), and the heat-sealing ring (10) is bonded and fixed between the foam ring (7) and the outer wall layer (6) by heat.

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