Flexible light composite cable pipe with health monitoring function for seabed resource development

Abstract

The invention relates to a flexible light composite cable pipe with health monitoring for seabed resource development, which comprises a non-adhesive multi-layer heterostructure, and the multi-layer heterostructure sequentially comprises a reinforced lining layer, a tensile armor layer, a middle sheath layer, a functional cable layer and an outer sheath layer from inside to outside; the reinforced lining layer is formed by compounding a supporting structure and a rubber material, and the supporting structure is formed by spirally winding a stainless steel band with a special-shaped section at a large angle; the inner side and the outer side of the tensile armor layer are wear-resistant layers, at least two tensile mechanical armor layers are arranged in the tensile armor layer, the number of the tensile mechanical armor layers is an even number, and a wear-resistant layer is arranged between every two adjacent tensile mechanical armor layers; the functional cable layer is formed by spirally winding a plurality of functional cables and filling strips; the layers are in close contact and are independent from one another, and the layers can slide relative to one another. The weight and bending rigidity of the pipe body are reduced, and the tensile rigidity and flexibility of the pipe body are improved.

Description

Technical Field

[0001] This application relates to the field of marine engineering systems and equipment technology, and in particular to a flexible, lightweight composite cable with health monitoring for seabed resource development. Background Technology

[0002] The development of deep-sea mineral resources is of significant strategic importance and national public interest. Among the discovered deep-sea mineral resources, those with major applications to human production and daily life include polymetallic nodules, cobalt-rich crusts, and polymetallic sulfides, which generally exist in irregular geometric shapes at depths of 300 to 6000 meters on the international seabed. After being collected and crushed by ore-collecting trucks, these minerals need to be transported to surface production vessels via long-distance pipelines. Simultaneously, power cables extending from the production vessel are required to provide energy support for the ore-collecting trucks. Therefore, deep-sea mineral transport pipelines and deep-sea power cables are crucial equipment for ensuring the safe development of deep-sea mineral resources.

[0003] In the patent publication CN115183067B, entitled "Manufacturing Method of Lightweight Composite Flexible Cable Conduit for Integrated Deep-Sea Mineral and Power Transportation," the cable conduit wall structure employs a three-layer structure: a wear-resistant layer, a support layer, and an inner sheath. This structure achieves wear resistance, radial support, and internal sealing functions, respectively. However, this three-layer structure reduces the cable conduit's flexibility while increasing its size and weight. In other known methods, cable conduits achieve lightweighting by using high-strength fiber prefabricated strips to create a tensile armor layer. While these fiber prefabricated strips currently possess high tensile strength, their low tensile stiffness makes it difficult to control cable conduit deformation under the low allowable strain of the functional cable, potentially leading to cable damage and failure. In common knowledge, the functional cable layer of a cable conduit provides power transmission and optical signal communication functions, but it does not have the ability to monitor the temperature, strain and linearity of the cable conduit in real time. Furthermore, the filling material of the functional cable layer is only composed of foam material, which cannot effectively weaken the pressure load on the functional cable when facing large external pressure, leading to the functional cable being damaged and failing under pressure.

[0004] In summary, the existing technology has the following problems: the single function of the cross-sectional layer results in limited lightweighting and flexibility of the cable conduit; the general high-strength fiber precast strips cannot achieve strict deformation control of the cable conduit, which can easily cause large deformation of the functional cables and damage; it does not have the function of real-time monitoring of cable conduit shape, and the filling material has a weak ability to withstand external pressure loads, making the functional cables susceptible to pressure damage.

[0005] Therefore, we propose a flexible, lightweight composite cable with health monitoring capabilities for seabed resource development. Summary of the Invention

[0006] To address the shortcomings of existing production technologies, the applicant provides a flexible, lightweight composite cable duct for seabed resource development with health monitoring capabilities. This improves the cable duct's structural form and function, reduces the weight and bending stiffness of the duct structure, and enhances the tensile stiffness and flexibility of the duct. Furthermore, it integrates mineral and photoelectric transport while adding the ability to monitor the cable duct's temperature, strain, and alignment in real time.

[0007] The technical solution adopted in this application is as follows: A flexible, lightweight composite cable with health monitoring capabilities for seabed resource development includes a non-bonded, multi-layered heterogeneous structure, wherein the multi-layered heterogeneous structure, from the inside out, comprises: The reinforcing liner is composed of a support structure and rubber material. The support structure is formed by spirally winding stainless steel strips with irregular cross sections at a large angle. The tensile armor layer has wear-resistant layers on both its inner and outer sides. The tensile armor layer contains at least two tensile mechanical armor layers, and the number of tensile mechanical armor layers is even. A wear-resistant layer is provided between two adjacent tensile mechanical armor layers. The inner sheath layer is used for internal separation and isolation; The functional cable layer is formed by spirally winding multiple functional cables and filler strips together. The outer sheath layer is used to cover and mold the entire structure. Each layer is in close contact with the others yet independent of them, and can slide relative to each other.

[0008] Its further features are: Each of the tensile mechanical armor layers is formed by spirally winding multiple narrow strips of high tensile modulus fibers with the same cross section. The high tensile modulus fiber strips are made by unidirectional fiber bonding with soft resin composite curing.

[0009] The high tensile modulus fiber narrow strip winding angles are opposite between the odd and even layers of the tensile armor layer.

[0010] The winding angle of the high tensile modulus fiber narrow strip is 20°-60°, and the laying tension of each high tensile modulus fiber narrow strip is the same.

[0011] The winding angle of the functional cable layer is greater than that of the winding angle of the tensile mechanical armor layer.

[0012] The functional cables include stranded power cables, armored optical fibers, network cables, and multimodal integrated monitoring cables that are evenly distributed along the circumference of the attachment.

[0013] The filler strip is made of a built-in high-toughness metal armored round tube wrapped with neoprene rubber material. The cross-sectional thickness of the filler strip is slightly higher than that of the functional cable. The filler strip is laid in the remaining gap space of the functional cable.

[0014] The multimodal integrated monitoring cable is made using Brillouin scattering and fiber optic grating technologies, integrating distributed fiber temperature monitoring and three-dimensional spatial line shape monitoring functions to sense the internal temperature field of the cable conduit and potential bending, twisting, and concentrated stress loads on the cable conduit line shape.

[0015] The power supply cross-section of a single power cable is obtained by dividing the total transmission power of the strands, and then combined with an effective insulation thickness, while ensuring that the cross-sectional thickness of the power cable is consistent with the cross-sectional thickness of the armored optical fiber and the network cable.

[0016] The support structure is covered with rubber material on both the inner and outer sides, and the thickness of the rubber material on the outer side of the support structure is less than the thickness of the rubber material on the inner side of the support structure.

[0017] The beneficial effects of this application are as follows: This application features a compact and rational structure, and is easy to operate. By replacing the existing three-layer structure of wear-resistant layer, support layer, and inner sheath layer with a reinforced inner lining layer, it improves the cable conduit's structural form and function, reduces the weight of the conduit, and utilizes rubber materials—a material difficult to replace polymer materials in existing technologies—further enhancing the cable conduit's structural performance, wear resistance, flexibility, and reducing bending stiffness. Furthermore, by replacing the high-strength fiber preforms in existing technologies with high-modulus fiber tape, it improves the cable conduit's tensile stiffness, and while accommodating integrated mineral and optoelectronic transport, it also enhances the ability to monitor cable conduit temperature, strain, and alignment in real time.

[0018] In addition, this application also has the following advantages: (1) A single tensile mechanical armor layer is made of multiple high tensile modulus fiber narrow strips with the same cross section spirally wound. The high tensile modulus fiber narrow strips are made by unidirectional fiber combined with soft resin composite curing to obtain high tensile modulus control of cable tube deformation. The high tensile modulus fiber narrow strips are wound at opposite angles between the odd and even layers of the tensile mechanical armor layer to ensure torsional balance when the cable tube is subjected to axial load.

[0019] (2) Functional cables include stranded power cables, armored optical fibers, network cables, and multimode integrated monitoring cables. The stranded power cables, armored optical fibers, and network cables are evenly distributed along the attached circumference. The multimode integrated monitoring cables are laid out according to their technical requirements. Filler strips are laid in the remaining gaps of the functional cables. The power cables are designed in strands according to the total cross-sectional requirements of the cables. The multimode integrated monitoring cables are made using Brillouin scattering technology and fiber optic grating technology. They integrate distributed optical fiber temperature monitoring and three-dimensional spatial line shape monitoring functions to sense the internal temperature field of the cable conduit and the possible bending, twisting, and concentrated stress loads on the cable conduit line shape. They can monitor the cable conduit temperature, strain, and line shape in real time.

[0020] (3) The filler strip is made of neoprene rubber material wrapped around a built-in high-toughness metal armored round tube. While fixing the functional cable winding structure, the filler strip also weakens the external pressure load. Therefore, the cross-sectional thickness of the filler strip is slightly higher than that of the functional cable. Finally, a layer of wrapping tape is wrapped around the outside of the functional cable and the filler strip to further stabilize the internal structure. Attached Figure Description

[0021] Figure 1 This is a three-dimensional schematic diagram of the cable conduit in this application.

[0022] Figure 2 This is a schematic cross-sectional view of the cable conduit in this application.

[0023] Figure 3 This is a schematic diagram of the longitudinal section of the cable conduit in this application.

[0024] Figure 4 This is a schematic diagram of the support structure of the reinforced inner lining layer of this application after being spirally wound.

[0025] Figure 5 This is a three-dimensional schematic diagram of the reinforced inner lining layer of this application.

[0026] Figure 6 This is a schematic cross-sectional view of the reinforced inner lining layer of this application.

[0027] Figure 7 This is a schematic longitudinal section of the reinforced inner lining layer of this application.

[0028] Figure 8 This is a schematic diagram of the high tensile modulus fiber narrow strip of the tensile mechanical armor layer of this application.

[0029] Figure 9 This is a three-dimensional view of the spiral winding and laying of the functional cables in the middle sheath layer and functional cable layer of this application.

[0030] Figure 10 This is a schematic cross-sectional view of the functional cable layer of this application.

[0031] The components include: 1. Reinforced inner lining layer; 2. Abrasion-resistant layer; 3. Tensile mechanical armor layer; 4. Middle sheath layer; 5. Functional cable layer; 6. Outer sheath layer; 7. Unidirectional fiber; 8. Soft resin; 9. Power cable; 10. Armored optical fiber; 11. Network cable; 12. Multimodal integrated monitoring cable; 13. Filler strip. Detailed Implementation

[0032] The specific embodiments of this application are described below with reference to the accompanying drawings.

[0033] like Figures 1-10As shown, a flexible lightweight composite cable duct for seabed resource development with health monitoring capabilities includes a non-bonded multi-layer heterogeneous structure. The multi-layer heterogeneous structure consists of, from the inside out, a reinforcing inner lining layer 1, a tensile armor layer, a middle sheath layer 4, a functional cable layer 5, and an outer sheath layer 6. Each layer is in close contact with the others yet independent of each other, and the layers can slide relative to each other.

[0034] The tensile armor layer has wear-resistant layers 2 on both its inner and outer sides. The tensile armor layer contains at least two tensile mechanical armor layers 3, and the number of tensile mechanical armor layers 3 is even. A wear-resistant layer 2 is provided between two adjacent tensile mechanical armor layers 3.

[0035] Each tensile mechanical armor layer 3 is made of multiple high tensile modulus fiber narrow strips with the same cross section spirally wound. The high tensile modulus fiber narrow strips are made by composite curing unidirectional fiber 7 with soft resin 8 to obtain high tensile modulus control of cable tube deformation. The tensile mechanical armor layer has three odd and even layers with opposite winding angles of high tensile modulus fiber narrow strips to ensure torsional balance when the cable tube is subjected to axial load.

[0036] In one embodiment, such as Figure 8 As shown, the cross-sectional shape of the high tensile modulus fiber narrow strip is rectangular.

[0037] In one embodiment, the winding angle of the high tensile modulus fiber narrow strip is 20°-60°. Each high tensile modulus fiber narrow strip is laid with the same tension to ensure that they have the same initial strain state.

[0038] In one embodiment, the unidirectional fiber 7 is made of lightweight non-metallic fibers such as aramid fiber, carbon fiber, and glass fiber, which can reduce the structural weight.

[0039] The tensile mechanical armor layer 3 is based on the tensile mechanical principle of spiral wound cylinder to achieve the ability to bear the axial load of the cable pipe. At the same time, the spiral winding makes the tensile mechanical armor layer 3 have a small bending stiffness, ensuring the flexibility of the cable pipe.

[0040] Compared with existing technologies that use high tensile strength fiber prefabricated strips to make tensile armor layers, the tensile mechanical armor layer 3 of this application can effectively and strictly control cable tube deformation.

[0041] like Figures 1-3 As shown, the tensile mechanical armor layer 3 has two layers, and an anti-wear layer 2 is provided between the two tensile mechanical armor layers 3.

[0042] The reinforcing inner liner 1 is composed of a support structure and a rubber material. The support structure is formed by spirally winding stainless steel strips with an irregular cross-section at a large angle, and then encapsulating it in the rubber material through vulcanization, thereby forming the reinforcing inner liner 1.

[0043] The reinforced inner lining layer 1 replaces the three-layer structure of wear-resistant layer, support layer and inner sheath layer in the existing technology, and uses high wear-resistant, low modulus rubber material that is difficult to apply in the existing technology, which further improves the performance of the cable tube structure.

[0044] The wear-resistant layer 2 is made of an ultra-thin spiral wound material and has a low coefficient of friction. It is mainly used to alleviate the friction damage of the tensile mechanical armor layer 3 when it is under load and slides, thus extending the service life of the cable tube.

[0045] Both the middle sheath layer 4 and the outer sheath layer 6 are formed by extrusion of polyethylene material, which is heated to a molten state and then extruded. The middle sheath layer 4 and the outer sheath layer 6 are used to separate and isolate the inner layers and to cover and form the overall structure, respectively. The middle sheath layer 4 is thinner, and its main function is to isolate the internal mineral fluids and transmit interlayer contact pressure, as well as to provide a core foundation for the winding and laying of functional cables. The outer sheath layer 6 is thicker, and its main function is to isolate the external environment, form the cable tube as a whole, and transmit external seawater pressure loads.

[0046] The outer sheath layer 6 is thicker than the middle sheath layer 4.

[0047] like Figures 9-10 As shown, the functional cable layer 5 is formed by spirally winding multiple functional cables and filler strips 13, with a winding angle greater than that of the tensile mechanical armor layer 3, thereby weakening the deformation of the functional cables; the functional cable layer 5 is then wrapped with wrapping tape to stabilize the cable forming structure. The functional cables include stranded power cables 9, armored optical fibers 10, network cables 11, and multimode integrated monitoring cables 12. The stranded power cables 9, armored optical fibers 10, and network cables 11 are evenly distributed along the attachment circumference, and the multimode integrated monitoring cables 12 are laid out according to their technical requirements. Filler strips 13 are laid in the remaining gaps of the functional cables. The power cable 9 is designed in a stranded manner according to the total cross-sectional requirements of the cable; the multimode integrated monitoring cables 12 are made using Brillouin scattering technology and fiber optic grating technology, integrating distributed optical fiber temperature monitoring and three-dimensional spatial line shape monitoring functions to sense the internal temperature field of the cable conduit and conditions such as bending, twisting, and concentrated stress loads that may occur on the cable conduit line shape, and can monitor the cable conduit temperature, strain, and line shape in real time; The filler strip 13 is made of a built-in high-toughness metal-armored cylindrical tube wrapped with neoprene rubber. While fixing the functional cable winding structure, the filler strip 13 also weakens external pressure loads; therefore, the cross-sectional thickness of the filler strip 13 is slightly higher than that of the functional cable. Finally, a layer of wrapping tape is wrapped around the functional cable and the filler strip 13 to further stabilize the internal structure.

[0048] The power supply cross-section of a single power cable 9 is obtained by dividing the total transmission power into strands, and then combined with an effective insulation thickness, while ensuring that the cross-sectional thickness of the power cable 9 is consistent with the cross-sectional thickness of the armored optical fiber 10 and the network cable 11. The armored optical fiber 10 is placed in a high-toughness thin-walled metal tube, and the material and thickness of the metal tube are designed and adjusted according to the environmental pressure load of the cable tube.

[0049] It features cable conduit health monitoring and the filler strip 13 can more effectively reduce external pressure on the functional cables.

[0050] The structure and function of the cable conduit have been improved, reducing the weight and bending stiffness of the conduit structure, increasing the tensile stiffness and flexibility of the conduit, and adding the ability to monitor the temperature, strain and alignment of the cable conduit in real time while taking into account the integrated transportation of minerals and optoelectronics.

[0051] This application replaces the three-layer structure of wear-resistant layer, support layer and inner sheath in the prior art with reinforced inner lining layer 1, which optimizes the cable tube structure and reduces the structural weight. Moreover, the reinforced inner lining layer 1 is made of rubber material, which has better wear resistance. Furthermore, the material modulus of rubber is much lower than that of polymer materials. Therefore, the cable tube of this application has lower bending stiffness and better flexibility.

[0052] This application uses a high tensile modulus fiber narrow strip, which ensures lightweight while better controlling the deformation of the tube and ensuring the safety of the functional cable.

[0053] This application adds a cable conduit health monitoring function, which can realize real-time monitoring of cable conduit temperature, strain, and cable type to ensure the safe use of the cable conduit. The functional cable layer 5 of this application uses a filler strip 13 with internal armor, which can more effectively bear the support function.

[0054] like Figure 4 As shown, a support structure is formed by spirally winding stainless steel strips with irregular cross-sections at a large angle using a cold rolling process. like Figures 5-7 As shown, the support structure is then encapsulated in the rubber material through vulcanization, thereby forming the reinforced inner liner 1.

[0055] Both the inner and outer sides of the support structure are covered with rubber material of a certain thickness. The outer layer of the support structure requires only a thin layer of rubber material, primarily serving to isolate the internal mineral fluids and transmit interlayer contact pressure. The thickness of the inner layer of the support structure is determined according to the wear resistance design requirements of the cable duct's inner wall; its main function is to construct a mineral transport channel and resist the abrasive effect of high-speed flowing slurry on the inner wall of the cable duct. The support structure provides radial support for the entire cable duct, maintaining its structural stability while resisting radial pressure caused by the external environment. The support structure is formed by interlocking large-angle windings of irregularly shaped cross-section stainless steel strips. The rubber material also has a very low modulus, resulting in low bending stiffness and excellent flexibility in the reinforced inner lining layer 1.

[0056] This application employs a composite structure with a reinforced inner liner 1, achieving integrated functions of high wear resistance, radial support, and internal sealing. This effectively reduces the weight and bending stiffness of the cable conduit, improving flexibility. High-modulus fiber narrow strips are used as tensile armor, effectively controlling conduit deformation while achieving lightweight construction, ensuring the safety of the functional cables. A cable conduit health monitoring function is added, enabling real-time monitoring of conduit temperature, deformation, and cable profile. The structure of the filler strip 13 is optimized to better support the cable and help it withstand external pressure.

[0057] The above description is an explanation of this application and not a limitation thereof. The scope of this application is defined by the claims. Within the scope of protection of this application, any form of modification may be made.

Claims

1. A flexible, lightweight composite cable pipe for health monitoring in seabed resource development, characterized in that, Including non-bonded multilayer heterostructures, the multilayer heterostructures are arranged from the inside out as follows: The reinforcing liner (1) is composed of a support structure and rubber material. The support structure is formed by spiral winding of stainless steel strips with irregular cross sections at a large angle. The tensile armor layer has wear-resistant layers (2) on both its inner and outer sides. The tensile armor layer has at least two tensile mechanical armor layers (3) inside, and the number of tensile mechanical armor layers (3) is even. A wear-resistant layer (2) is provided between two adjacent tensile mechanical armor layers (3). The middle sheath layer (4) is used for internal separation and isolation; The functional cable layer (5) is formed by spirally winding multiple functional cables and filler strips (13); The outer sheath layer (6) is used to cover and form the whole; Each layer is in close contact with the others yet independent of them, and can slide relative to each other.

2. The flexible, lightweight composite cable duct for health monitoring in seabed resource development as described in claim 1, characterized in that: Each of the tensile mechanical armor layers (3) is made of multiple high tensile modulus fiber narrow strips with the same cross section spirally wound together. The high tensile modulus fiber narrow strips are made by composite curing unidirectional fiber (7) with soft resin (8).

3. The flexible, lightweight composite cable duct for health monitoring in seabed resource development as described in claim 2, characterized in that: The tensile mechanical armor layer (3) of the tensile armor layer has opposite winding angles between the odd and even layers of the high tensile modulus fiber narrow strip.

4. A flexible, lightweight composite cable duct for health monitoring in seabed resource development as described in claim 2, characterized in that: The winding angle of the high tensile modulus fiber narrow strip is 20°-60°, and the laying tension of each high tensile modulus fiber narrow strip is the same.

5. A flexible, lightweight composite cable duct for health monitoring in seabed resource development as described in claim 4, characterized in that: The winding angle of the functional cable layer (5) is greater than that of the winding angle of the tensile mechanical armor layer (3).

6. A flexible, lightweight composite cable duct for health monitoring in seabed resource development as described in claim 1, characterized in that: The functional cable includes a stranded power cable (9) evenly distributed along the attached circumference, armored optical fiber (10), network cable (11), and multimodal integrated monitoring cable (12).

7. A flexible, lightweight composite cable duct for health monitoring in seabed resource development as described in claim 6, characterized in that: The filler strip (13) is made of a built-in high-toughness metal armored round tube wrapped with neoprene rubber material. The cross-sectional thickness of the filler strip (13) is slightly higher than that of the functional cable. The filler strip (13) is arranged in the remaining gap space of the functional cable.

8. A flexible, lightweight composite cable duct for health monitoring in seabed resource development as described in claim 6, characterized in that: The multimodal integrated monitoring cable (12) is made using Brillouin scattering technology and fiber optic grating technology. It integrates distributed fiber temperature monitoring and three-dimensional spatial line shape monitoring functions to sense the internal temperature field of the cable tube and the bending, twisting, and concentrated stress loads that may occur on the cable tube line shape.

9. A flexible, lightweight composite cable duct for health monitoring in seabed resource development as described in claim 6, characterized in that: The power supply cross-section of a single power cable (9) is obtained by dividing the total transmission power of the strands and then adding an effective insulation thickness, while ensuring that the cross-sectional thickness of the power cable (9) is consistent with the cross-sectional thickness of the armored optical fiber (10) and the network cable (11).

10. A flexible, lightweight composite cable with health monitoring for seabed resource development as described in claim 1, characterized in that: The support structure is covered with rubber material on both the inner and outer sides, and the thickness of the rubber material on the outer side of the support structure is less than the thickness of the rubber material on the inner side of the support structure.

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