Cavity composite pipe for conveying hydrogen
By designing a cavity composite pipe composed of multi-layer composite materials, the leakage and explosion risks caused by hydrogen corrosion in metal pipes under high temperature and high pressure are solved, and the safety and reliability of hydrogen transportation are achieved.
Patent Information
- Application Number
- CN202422377504.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2025-08-05
- Estimated Expiration
- 2034-09-27
AI Technical Summary
When existing metal pipes transport hydrogen in high temperature and high pressure environments, hydrogen corrosion is prone to occur, resulting in leakage and explosion risks, and leakage is difficult to detect in a timely manner.
The cavity composite tube consisting of PE-RT outer layer, outer glass fiber layer, aluminum tape layer, PE cavity layer, inner glass fiber layer, aramid layer and PE inner layer is adopted. Through the combined design and structural optimization of each layer, it blocks and accommodates hydrogen permeation to avoid direct hydrogen emissions.
It improves the safety of hydrogen transportation, can withstand high temperature and high pressure, reduces the permeability of hydrogen, and prevents hydrogen from being directly discharged into the air in the pipeline, enhancing the pressure bearing capacity and barrier effect of the pipeline.
Smart Images
Figure CN223191182U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of hydrogen transportation, and more specifically, to a cavity composite pipe for transporting hydrogen. Background Art
[0002] In the current industry, the pipelines for transporting hydrogen mainly use metal materials. When the hydrogen pipelines made of metal materials are transporting hydrogen, due to the small molecular diameter and low density of hydrogen, small-molecule hydrogen is easy to penetrate into the metal pipes. When hydrogen penetrates into the inner cavity of the metal pipelines, hydrogen will change the structure of the metal pipelines, resulting in hydrogen corrosion on the metal pipelines. When the problem of hydrogen corrosion occurs on the metal pipelines, it will cause permanent damage to the metal pipelines, greatly increasing the possibility of pipe material failure, extremely likely causing hydrogen leakage, and even leading to pipeline rupture or explosion in severe cases. And with the increase of the pressure inside the hydrogen pipeline and the rise of the pipeline temperature, the probability of hydrogen corrosion on the metal pipeline will further increase.
[0003] However, at the current stage, when using metal pipelines for hydrogen energy transportation, due to the excessively long length of the hydrogen pipelines, it is difficult to detect in time when the hydrogen pipelines in a high-temperature and high-pressure environment leak. The leaked hydrogen is directly discharged into the air, which is easy to cause an explosion, bringing huge hidden dangers to life safety and property safety. Content of the Utility Model
[0004] The purpose of the utility model is to overcome the deficiency that it is difficult to detect in time when the hydrogen pipeline in a high-temperature and high-pressure environment leaks in the prior art, resulting in the leaked hydrogen being directly discharged into the air and easily causing hydrogen explosion, and to provide a cavity composite pipe for transporting hydrogen. The pipeline in the utility model can withstand high temperature and high pressure during hydrogen transportation, and can also prevent hydrogen from being directly discharged into the air, improving the safety during hydrogen transportation.
[0005] To solve the above technical problems, the technical scheme adopted by the utility model is:
[0006] Provide a cavity composite pipe for transporting hydrogen. The composite pipe sequentially includes a PE-RT outer layer, an outer fiberglass layer, an aluminum tape layer, a PE cavity layer, an inner fiberglass layer, an aramid layer, and a PE inner layer from outside to inside. The PE cavity layer includes several cavities. The several cavities are arranged in a circumferential pattern with the axis of the composite pipe as the center of the circle. The adjacent two cavities are separated by partitions, and the several cavities are not connected to each other.
[0007] A cavity composite pipe for hydrogen transportation in the present utility model. The PE inner layer can achieve an excellent effect of blocking hydrogen; the aramid layer can play a role in bearing pressure; the inner fiberglass layer can further improve the pressure-bearing capacity of the pipeline. The PE cavity layer can not only further enhance the effect of blocking hydrogen, but the cavities provided inside it can also accommodate the hydrogen that penetrates into the PE cavity layer. After the hydrogen penetrates into the cavity, the difficulty of the hydrogen moving inside the cavity is significantly less than the difficulty of the hydrogen further penetrating outward, so that the hydrogen penetrating into the cavity is stored in the cavity, achieving the effect of preventing the hydrogen from continuing to penetrate and avoiding the leakage of hydrogen to the outside. The aluminum tape layer can further block the outward penetration of hydrogen in the PE cavity layer; the outer fiberglass layer serves the purpose of enhancing the pressure-bearing capacity of the cavity channel layer; the PE-RT outer layer can withstand high temperatures, isolate external fire sources and high temperatures, and avoid damaging the internal structure of the pipeline. Therefore, the composite pipe in the present utility model can withstand high temperatures and high pressures during hydrogen transportation, reduce the penetration speed of hydrogen in the pipeline, and can also prevent the hydrogen penetrating into the pipeline from being directly discharged into the air, improving the safety during hydrogen transportation.
[0008] Further, the PE inner layer is a composite co-extruded layer of high-density polyethylene and ethylene-vinyl alcohol copolymer, and the thickness of the PE inner layer is 6 mm - 7 mm. The PE inner layer is formed by the composite co-extrusion of high-density polyethylene and ethylene-vinyl alcohol copolymer. High-density polyethylene is the HDPE material, and ethylene-vinyl alcohol copolymer is the EVOH material. The PE inner layer formed after the composite co-extrusion of the two has a uniform texture and stable properties, and it is difficult for hydrogen to penetrate into the PE inner layer. Although the greater the thickness of the PE inner layer, the better the effect of blocking hydrogen, at the same time, the greater the thickness of the PE inner layer, the higher the cost of the composite pipe. Through experiments, it is measured that when the thickness of the PE inner layer is between 6 - 7 mm, it can not only have a good effect of blocking hydrogen, but also avoid increasing the cost of the composite pipe.
[0009] Further, the aramid layer includes aramid fiber tapes wound around the outside of the PE inner layer, and the thickness of the aramid layer is 1.5 mm - 2.5 mm. The aramid layer is formed by winding aramid fiber tapes. The aramid fiber tapes are wound around the outside of the PE inner layer. The winding methods of the aramid fiber tapes include but are not limited to spiral winding and circumferential winding. The aramid layer wound by the aramid fiber tapes has excellent impact resistance, and because it is tough and can absorb a large amount of energy and will not break under pressure, the pipeline has a good pressure-bearing effect. The greater the thickness of the aramid layer, the better the pressure-bearing effect, and at the same time the higher the cost. Through experiments, it is measured that when the thickness of the aramid layer is 1.5 mm - 2.5 mm, the composite pipe has a good pressure-bearing effect on the premise of avoiding increasing the cost of the composite pipe.
[0010] Furthermore, the inner fiberglass layer includes fiberglass tapes wound around the outer side of the aramid layer, and the thickness of the inner fiberglass layer is 1.5 mm - 2.5 mm. The inner fiberglass layer is formed by winding fiberglass tapes. The fiberglass tapes are wound around the outer side of the aramid layer. The winding methods of the fiberglass tapes include, but are not limited to, spiral winding and circumferential winding. The inner fiberglass layer formed by winding fiberglass tapes is not only high-temperature resistant and heat-insulating, but also has high tensile strength, further enhancing the pressure-bearing capacity of the pipeline. Similarly, the greater the thickness of the inner fiberglass layer, the higher the pressure-bearing effect, and the higher the cost at the same time. Through experiments, it is measured that when the thickness of the inner fiberglass layer is 1.5 mm - 2.5 mm, the composite pipe has a good pressure-bearing effect on the premise of avoiding increasing the cost of the composite pipe.
[0011] Furthermore, the PE cavity layer is a composite co-extrusion layer of high-density polyethylene and ethylene-vinyl alcohol copolymer. The thickness of the PE cavity layer is 12 mm - 13 mm. The thickness of the cavity is 0.4 - 0.6 times the thickness of the PE cavity layer. The central angle corresponding to each cavity is the same, and the central angle corresponding to each partition is the same. The ratio of the central angle corresponding to the partition to the central angle corresponding to the cavity is 1:4 - 1:6.
[0012] The PE cavity layer is a composite co-extrusion layer of high-density polyethylene and ethylene-vinyl alcohol copolymer. High-density polyethylene is the HDPE material, and ethylene-vinyl alcohol copolymer is the EVOH material. The PE cavity layer formed after the two are composite co-extruded has uniform texture and stable properties, and it is difficult for hydrogen to penetrate into the PE cavity layer. And there are cavities in the PE cavity layer. When hydrogen penetrates into the PE cavity layer, the hydrogen that penetrates into the PE cavity layer will enter the cavities in the PE cavity layer during the penetration process. The difficulty of the hydrogen that penetrates into the cavities moving in the cavities is significantly lower than the difficulty of the hydrogen continuing to penetrate outward. The hydrogen in the cavities will continue to move forward along the cavities instead of penetrating outward, achieving the purpose of avoiding hydrogen leakage to the outside. Through experiments, it is proved that when the thickness of the PE cavity layer is 12 mm - 13 mm and the thickness of the cavity is 0.4 - 0.6 times the thickness of the PE cavity layer, the PE cavity layer can play a good barrier role in hydrogen and prevent it from diffusing outward. On this basis, the cavities in the PE cavity layer can accommodate more hydrogen, so that the hydrogen that enters the cavity layer will not continue to diffuse outward. When the ratio of the central angle corresponding to the partition to the central angle corresponding to the cavity is 1:4 - 1:6, the partition can not only play a good supporting role for the PE cavity layer, but also avoid hydrogen penetration between adjacent cavities.
[0013] Furthermore, the number of the cavities is 3 - 8. The more the number of cavities is, the smaller the central angle corresponding to each cavity is, and the smaller the central angle corresponding to each partition is, that is, the smaller the thickness of the partition is, and the greater the probability of hydrogen permeation between adjacent cavities through the partition. Therefore, when the number of cavities is limited to 3 - 8, the partitions between the cavities can have both good supporting effects and anti - permeation functions.
[0014] Furthermore, the shapes of several of the cavities are the same or different. The shapes of the cavities can be the same or different. The shapes of the cavities can be arc - shaped, wavy or other irregular shapes.
[0015] Furthermore, the aluminum tape layer includes aluminum tapes wound around the outer surface of the PE cavity layer, and the aluminum tapes are fixed by welding. The thickness of the aluminum tape layer is 1.5 mm - 2.5 mm. The aluminum tape layer is formed by winding aluminum tapes. The aluminum tapes are wound on the outer side of the PE cavity layer. The winding methods of the aluminum tapes include but are not limited to spiral winding and circumferential winding. The aluminum tape layer formed by winding aluminum tapes can further isolate the hydrogen permeating outward from the PE cavity layer. The greater the thickness of the aluminum tape layer is, the better the hydrogen isolation effect is, and the higher the cost is. Through experiments, it is measured that when the thickness of the aluminum tape is 1.5 mm - 2.5 mm, on the premise of avoiding increasing the cost of the composite pipe, the aluminum tape layer in the composite pipe can have a good hydrogen isolation effect.
[0016] Furthermore, the outer glass fiber layer includes glass fiber tapes wound around the outer side of the aluminum tape layer. The thickness of the outer glass fiber layer is 1.5 mm - 2.5 mm. The outer glass fiber layer is formed by winding glass fiber tapes. The glass fiber tapes are wound on the outer side of the aramid layer. The winding methods of the glass fiber tapes include but are not limited to spiral winding and circumferential winding. The outer glass fiber layer formed by winding glass fiber tapes is not only high - temperature resistant and heat - insulating, but also has high tensile strength, further enhancing the pressure resistance of the pipeline. The greater the thickness of the outer glass fiber layer is, the better the pressure - bearing effect is, and the higher the cost is. Through experiments, it is measured that when the thickness of the outer glass fiber layer is 1.5 mm - 2.5 mm, on the premise of avoiding increasing the cost of the composite pipe, the outer glass fiber layer in the composite pipe can have a good pressure - bearing effect.
[0017] Furthermore, the PE - RT outer layer is a heat - resistant polyethylene extrusion layer, and the thickness of the PE - RT outer layer is 4 mm - 5 mm. The PE - RT outer layer is a medium - density heat - resistant polyethylene extrusion layer made of PE modified materials, which has good heat resistance and can isolate external fire sources and high - temperature objects, avoiding high - temperature damage to the pipeline. The greater the thickness of the PE - RT outer layer is, the better the heat resistance of the pipeline is, and the higher the cost is. Through experiments, it is measured that when the thickness of the PE - RT outer layer is 4 mm - 5 mm, on the premise of avoiding increasing the cost of the composite pipe, the PE - RT outer layer in the composite pipe can have a good heat - insulation effect.
[0018] Compared with the prior art, the beneficial effects of the utility model are as follows:
[0019] A cavity composite pipe for hydrogen transportation of the utility model can withstand high temperature and high pressure during hydrogen transportation, reduce the hydrogen permeation rate in the pipeline, and can also prevent the hydrogen permeating into the pipeline from being directly discharged into the air, improving the safety during hydrogen transportation.
[0020] A cavity composite pipe for hydrogen transportation of the utility model. The PE cavity layer in the composite pipe can not only have a good barrier effect on hydrogen, but the cavities therein can accommodate the hydrogen diffused into the PE cavity layer, preventing the outward diffusion of hydrogen and causing hydrogen leakage.
[0021] A cavity composite pipe for hydrogen transportation of the utility model. The PE inner layer in the composite pipe can achieve an excellent hydrogen barrier effect; the aramid layer can play a pressure-bearing role; the inner fiberglass layer can further improve the pressure-bearing capacity of the pipeline; the aluminum strip layer can further prevent the hydrogen in the PE cavity layer from permeating outward; the outer fiberglass layer serves to enhance the pressure-bearing capacity of the cavity channel layer; the PE-RT outer layer can withstand high temperature, isolate external ignition sources and high temperatures, and prevent it from damaging the internal structure of the pipeline. Description of the Drawings
[0022] Figure 1 It is a schematic structural diagram of the end face of a cavity composite pipe for hydrogen transportation;
[0023] Figure 2 It is a schematic internal structure diagram of a cavity composite pipe for hydrogen transportation;
[0024] Figure 3 It is a cavity composite pipe for hydrogen transportation Figure 2 Enlarged view of part A in;
[0025] Figure 4 It is a schematic structural diagram of a cavity composite pipe for hydrogen transportation.
[0026] In the drawings: 100, composite pipe; 1, PE-RT outer layer; 2, outer fiberglass layer; 3, aluminum strip layer; 4, PE cavity layer; 5, inner fiberglass layer; 6, aramid layer; 7, PE inner layer; 401, cavity; 402, partition. Detailed Embodiments
[0027] The present utility model will be further described in conjunction with specific embodiments. Among them, the attached drawings are only for illustrative purposes, showing only schematic diagrams rather than physical diagrams, and should not be construed as a limitation to this patent; in order to better illustrate the embodiments of the present utility model, some components in the attached drawings will be omitted, enlarged or reduced, and do not represent the dimensions of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the attached drawings may be omitted.
[0028] In the attached drawings of the embodiments of the present utility model, the same or similar reference numerals correspond to the same or similar components; in the description of the present utility model, it should be understood that if there are terms such as "upper", "lower", "left", "right", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the attached drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the attached drawings are only for illustrative purposes and should not be construed as a limitation to this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.
[0029] Embodiment 1
[0030] This embodiment is the first embodiment of a cavity composite pipe for hydrogen transportation. As Figures 1 - 4 shown, the composite pipe 100100 sequentially includes a PE-RT outer layer 1, an outer fiberglass layer 2, an aluminum tape layer 3, a PE cavity layer 4, an inner fiberglass layer 5, an aramid layer 6, and a PE inner layer 7 from the outside to the inside. The PE cavity layer 4 includes a plurality of cavities 401. The plurality of cavities 401 are arranged in a circular pattern with the axis of the composite pipe 100100 as the center. The adjacent two cavities 401 are separated by a partition 402, and the plurality of cavities 401 are not connected to each other.
[0031] The beneficial effects of this embodiment are as follows: When the composite pipe 100 transports hydrogen, it can withstand high temperatures, high pressures, reduce the hydrogen permeation rate in the pipeline, and also avoid the direct emission of hydrogen permeating into the pipeline into the air, improving the safety during hydrogen transportation. Specifically, the PE inner layer 7 can achieve an excellent effect of blocking hydrogen; the aramid layer 6 can play a role in bearing pressure; the inner fiberglass layer 5 can further improve the pressure-bearing capacity of the pipeline. The PE cavity layer 4 can not only further enhance the effect of blocking hydrogen, but the cavities 401 provided inside it can also accommodate the hydrogen permeating into the PE cavity layer 4. After the hydrogen permeates into the interior of the cavity 401, the hydrogen is more likely to move inside the cavity 401, so that the hydrogen permeating into the cavity 401 is stored in the cavity 401, achieving the effect of preventing the continuous permeation of hydrogen and avoiding the outward leakage of hydrogen. The aluminum strip layer 3 can further block the outward permeation of hydrogen in the PE cavity layer 4; the outer fiberglass layer 2 serves the purpose of enhancing the pressure-bearing capacity of the cavity 401 channel layer; the PE-RT outer layer 1 can withstand high temperatures, isolate external ignition sources and high temperatures, and avoid damaging the internal structure of the pipeline.
[0032] Embodiment Two
[0033] This embodiment is the second embodiment of a cavity composite pipe for hydrogen transportation. On the basis of Embodiment One, as Figure 1 and Figure 3 shown, the PE cavity layer 4 is further defined.
[0034] Specifically, the PE cavity layer 4 is a composite co-extrusion layer of high-density polyethylene and ethylene-vinyl alcohol copolymer. The thickness of the PE cavity layer 4 is 12.5 mm, and the thickness of the cavity 401 is 0.6 times the thickness of the PE cavity layer 4. The number of cavities 401 is five. The shapes of the five cavities 401 are the same, all being arc-shaped. The central angle corresponding to each cavity 401 is 60°, the central angle corresponding to each partition 402 is 12°, and the ratio of the central angle corresponding to the partition 402 to the central angle corresponding to the cavity 401 is 1:5.
[0035] The beneficial effects of this embodiment are as follows: The high-density polyethylene and ethylene-vinyl alcohol copolymer in the PE cavity layer 4 can reduce the hydrogen permeation rate, and most of the hydrogen permeating into the PE cavity layer 4 will enter the cavity 401 in the PE cavity layer 4 during the permeation process. The difficulty of the hydrogen permeating into the cavity 401 moving inside the cavity 401 is significantly lower than the difficulty of the hydrogen continuing to permeate outward. Therefore, the hydrogen in the cavity 401 will continue to move forward along the cavity 401 instead of permeating outward.
[0036] The thickness of the PE cavity layer 4 is 12.5 mm. When the thickness of the cavity 401 is 0.6 times that of the PE cavity layer 4, the cavity 401 layer of the e-cavity can play a good role in blocking hydrogen and preventing its outward diffusion. On this basis, the cavity 401 in the PE cavity layer 4 can accommodate more hydrogen, so that the hydrogen entering the cavity 401 layer will not continue to diffuse outward. The number of cavities 401 is five. When the central angle corresponding to each cavity 401 is 60° and the central angle corresponding to each partition 402 is 12°, the partition 402 can not only play a good supporting role for the PE cavity layer 4, but also prevent hydrogen from permeating between adjacent cavities 401. The shapes of the five cavities 401 are all arc-shaped, which is more convenient for the processing of the cavity 401.
[0037] Embodiment III
[0038] This embodiment is the third embodiment of a cavity composite pipe for transporting hydrogen. On the basis of Embodiment I and Embodiment II, as Figures 1 - 3 shown, other structures of the composite pipe 100 are further defined.
[0039] Specifically, the PE inner layer 7 is a composite co-extrusion layer of high-density polyethylene and ethylene-vinyl alcohol copolymer, and the thickness of the PE inner layer 7 is 6 mm.
[0040] Specifically, the aramid layer 6 includes aramid fiber tapes wound around the outer side of the PE inner layer 7. The thickness of the aramid layer 6 is 2 mm. The aramid layer 6 is formed by winding aramid fiber tapes, and the aramid fiber tapes are helically wound around the outer side of the PE inner layer 7.
[0041] Specifically, the inner glass fiber layer 5 includes glass fiber tapes wound around the outer side of the aramid layer 6. The thickness of the inner glass fiber layer 5 is 2 mm. The inner glass fiber layer 5 is formed by winding glass fiber tapes, and the glass fiber tapes are helically wound around the outer side of the aramid layer 6.
[0042] Specifically, the aluminum tape layer 3 includes aluminum tapes wound around the outer surface of the PE cavity layer 4. The aluminum tapes are welded and fixed. The thickness of the aluminum tape layer 3 is 2 mm. The aluminum tape layer 3 is formed by winding aluminum tapes, and the aluminum tapes are helically wound around the outer side of the PE cavity layer 4. The gap between the outermost aluminum tape and the aluminum tapes on the aluminum tape layer 3 is sealed by welding.
[0043] Specifically, the outer glass fiber layer 2 includes glass fiber tapes wound around the outer side of the aluminum tape layer 3. The thickness of the outer glass fiber layer 2 is 2 mm. The outer glass fiber layer 2 is formed by winding glass fiber tapes, and the glass fiber tapes are helically wound around the outer side of the aramid layer 6.
[0044] Specifically, the PE-RT outer layer 1 is a heat-resistant polyethylene extrusion layer, and the thickness of the PE-RT outer layer 1 is 4 mm.
[0045] The beneficial effects of this embodiment are as follows: The PE inner layer 7 can reduce the speed of hydrogen permeating into the PE inner layer 7. The aramid layer 6 has excellent impact resistance, enabling the pipe to have good pressure-bearing effect. The helically wound aramid fiber tape has a fast winding speed and high efficiency. The inner glass fiber layer 5 and the outer glass fiber layer 2 can further increase the pressure-bearing capacity of the composite pipe 100. The helically wound glass fiber tape has a fast winding speed and high production efficiency. The aluminum tape layer 3 formed by helically winding aluminum tape has a good hydrogen isolation effect, further preventing hydrogen from permeating outwards. The PE-RT outer layer 1 can isolate external ignition sources and high-temperature objects, avoiding damage to the pipeline caused by high temperature.
[0046] In the specific content of the above specific implementation manner, each technical feature can be combined arbitrarily without contradiction. For the sake of concise description, not all possible combinations of the above technical features are described. However, as long as the combinations of these technical features do not exist in contradiction, they should be considered as the scope recorded in this specification.
[0047] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the implementation manners here. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.
Claims
1. A cavity composite tube for transporting hydrogen, characterized in that: The composite pipe (100) comprises, from outside to inside, a PE-RT outer layer (1), an outer glass fiber layer (2), an aluminum tape layer (3), a PE cavity layer (4), an inner glass fiber layer (5), an aramid layer (6) and a PE inner layer (7); the PE cavity layer (4) comprises a plurality of cavities (401); the plurality of cavities (401) are arranged in a circle with the axis of the composite pipe (100) as the center; adjacent two cavities (401) are separated by a partition (402); and the plurality of cavities (401) are not connected to each other.
2. The cavity composite tube for transporting hydrogen according to claim 1, characterized in that: The PE inner layer is a composite co-extruded layer of high-density polyethylene and ethylene-vinyl alcohol copolymer, and the thickness of the PE inner layer is 6mm-7mm.
3. The cavity composite tube for transporting hydrogen according to claim 1, characterized in that: The aramid layer (6) comprises an aramid fiber tape wound around the outside of the PE inner layer, and the thickness of the aramid layer (6) is 1.5 mm to 2.5 mm.
4. The cavity composite tube for transporting hydrogen according to claim 1, characterized in that: The inner glass fiber layer (5) comprises a glass fiber tape wound around the outside of the aramid layer (6), and the thickness of the inner glass fiber layer (5) is 1.5 mm to 2.5 mm.
5. The cavity composite tube for transporting hydrogen according to claim 1, characterized in that: The PE cavity layer (4) is a composite co-extruded layer of high-density polyethylene and ethylene-vinyl alcohol copolymer, the thickness of the PE cavity layer (4) is 12 mm to 13 mm, the thickness of the cavity (401) is 0.4 to 0.6 times the thickness of the PE cavity layer (4), the central angle angle corresponding to each cavity (401) is the same, the central angle angle corresponding to each baffle (402) is the same, and the ratio of the central angle corresponding to the baffle (402) to the central angle angle corresponding to the cavity (401) is 1:4 to 1:
6.
6. The cavity composite tube for transporting hydrogen according to claim 5, characterized in that: The number of the cavities (401) is 3-8.
7. The cavity composite tube for transporting hydrogen according to claim 5, characterized in that: The shapes of each of the cavities (401) are the same or different.
8. The cavity composite tube for transporting hydrogen according to claim 1, characterized in that: The aluminum strip layer (3) comprises an aluminum strip wound around the outer surface of the PE cavity layer (4), the aluminum strip is fixed by welding, and the thickness of the aluminum strip layer (3) is 1.5 mm to 2.5 mm.
9. The cavity composite tube for transporting hydrogen according to claim 1, characterized in that: The outer glass fiber layer (2) comprises a glass fiber tape wound around the outside of the aluminum tape layer (3), and the thickness of the outer glass fiber layer (2) is 1.5 mm to 2.5 mm.
10. The cavity composite tube for transporting hydrogen according to claim 1, characterized in that: The PE-RT outer layer (1) is a heat-resistant polyethylene extrusion layer, and the thickness of the PE-RT outer layer (1) is 4 mm to 5 mm.