Polar low-temperature-resistant through-hull cable for ships and method for manufacturing the same

Abstract

The application provides a kind of polar low temperature resistant marine through-cabin cable and its preparation method, the through-cabin cable includes the insulated wire core being composed of longitudinally water-blocking stranded conductor and conductor insulation layer, and the cable core is stranded and formed with filling core, and the water-proof inner lining layer, braided armor layer, water-proof reinforcing layer, sheath layer and through-cabin buffer layer are designed layer by layer on the outer surface of the cable core.The application extrudes and packs pure EVA resin water-proof inner lining layer outside the cable core, adds a layer of through-cabin protective layer outside the sheath, and realizes the cable resistance-55 DEG C low temperature, resistance to seawater, easy through-cabin bonding performance through the compatibility of through-cabin protective layer and outer sheath layer, there is no plasticizer precipitation on the surface of the cable in low temperature seawater environment, the precipitation is still deposited in the buffer layer, the vulcanization seal between the cable and the through-cabin penetrating piece is not layered, the vulcanization seal between the cable body structure and the penetrating piece is prevented from being layered, so as to improve the through-sealing and bonding performance of the cable through-cabin in seawater corrosion and extremely low temperature environment.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and in particular to low-temperature resistant cables, specifically to a polar low-temperature resistant marine cable with a method for its preparation. Background Technology

[0002] With the implementation of the Arctic shipping strategy, polar vessels are developing rapidly, leading to a growing demand for supporting cables with stringent technical performance requirements. Due to the unique low-temperature environment of the polar regions, the supporting through-hull cables (cables that pass through the bulkhead from inside the hull to the outside) must not only withstand temperatures as low as -55°C, but also ensure reliable penetration sealing between the cable and fittings such as penetration components and stuffing boxes at this low temperature. Existing polar low-temperature resistant, oil-resistant, UV-resistant, and salt-spray resistant cables can meet the requirements for laying in the polar external environment, but they do not meet the requirements for through-hull laying in the low-temperature polar environment.

[0003] Existing polar marine cables only possess low-temperature resistance; however, in the environment of both extreme low temperatures and seawater, the sheath material suffers from plasticizer leaching, which adheres to the sheath surface and forms a barrier layer between the sheath and accessories such as penetrations. This makes the seal between the cable and accessories prone to delamination and failure, such as… Figure 1a , 1b As shown, the interface seal between the cable and the cabin accessory is damaged, resulting in a cabin seal failure, which leads to water leakage, air leakage, moisture corrosion and other faults between the cable and the accessory. Summary of the Invention

[0004] The purpose of this invention is to provide a polar cryogenic marine cable and its preparation method that can meet the requirements of cable laying through the cabin from inside to outside the cabin in polar low-temperature environments. While achieving the cable's resistance to low temperatures of -55℃, seawater corrosion, and salt spray electrical properties, it also improves the sealing performance of the polar cryogenic cable in the cabin laying environment, avoiding problems such as water leakage, air leakage, and seawater erosion caused by breakage, delamination, and separation between the cable and accessories.

[0005] According to a first aspect of the present invention, a polar cryogenic marine through-hull cable is provided, comprising:

[0006] Stranded conductors are formed by stranding multiple single wires together, with hydrophobic sealant filling the spaces between the stranded wires.

[0007] A conductor insulation layer is extruded onto the outer surface of the stranded conductor, and the stranded conductor and the conductor insulation layer form an insulated core.

[0008] A cable core with a circular cross-section is formed by twisting multiple insulated wire cores according to a predetermined pitch ratio. During the twisting process, the gaps between the insulated wire cores are filled with filler cores of the same material but different specifications as the conductor insulation layer. The insulated wire cores and filler cores come into contact with each other and are twisted together to form a cable. The remaining gaps between the insulated wire cores and filler cores in the cable core are filled with hydrophobic sealant.

[0009] A waterproof inner lining layer made of pure-grade EVA resin is extruded over the cable core of the cable.

[0010] A woven armor layer is formed on the outer surface of the waterproof inner lining.

[0011] EVA tape is overlapped and wrapped around the outer surface of the woven armor layer to form a waterproof reinforcement layer; and

[0012] A sheath layer and a buffer layer for penetration are sequentially formed on the outer surface of the waterproof reinforcement layer;

[0013] The sheath layer and the through-cabin buffer layer are formed by double-layer co-extrusion process, and both have the same low-temperature resistant and waterproof material as the base material, so that they can be co-extruded to form a compatible and tight bond. The through-cabin buffer layer constitutes the isolation layer between the cable sheath layer and the through-cabin penetrating component.

[0014] As an optional embodiment, in the combination of the sheath layer and the cabin buffer layer, the sheath layer serves as the inner layer and is made of a low-temperature resistant, waterproof, chlorosulfonated polyethylene mixture, while the cabin buffer layer serves as the outer layer and is made of a chlorosulfonated polyethylene mixture doped with hardness-modified fillers, with a Shore A hardness of 90-95.

[0015] As an optional embodiment, the extrusion thickness of the cabin buffer layer is (0.3~0.4) mm, and the thickness of the sheath layer is greater than the thickness of the cabin buffer layer.

[0016] As an optional embodiment, the conductor insulation layer is double-extruded, consisting of an insulating buffer layer bonded to a hydrophobic sealant filled between the stranded conductors and individual wires, and an insulating layer on the surface of the insulating buffer layer. The insulating buffer layer is made of vinyl resin material, and the insulating layer is made of vinyl waterproof rubber and plastic material.

[0017] As an optional embodiment, the pure-grade EVA resin used in the waterproof lining layer does not contain any rubber and plastic additives.

[0018] As an optional embodiment, the braided armor layer is made of tin-plated copper single wires woven on the outer surface of the waterproof inner lining layer. After the armor is woven, glue is injected between the tin-plated copper single wires to fill the gaps between the armor single wires with hydrophobic sealant, and then EVA tape is wrapped around it.

[0019] As an optional embodiment, an EVA tape is overlapped and wrapped around the woven armor layer to form a waterproof reinforcement layer. The waterproof reinforcement layer is penetrated and bonded by injected hydrophobic sealant and forms an integral seal with the woven armor layer.

[0020] In a second aspect of the present invention, a method for preparing a polar cryogenic marine through-hull cable is also provided, comprising:

[0021] Stranded conductor preparation: Multiple tin-plated copper single wires of the same diameter are regularly stranded together, and hydrophobic sealant is filled between the stranded single wires to prepare a stranded conductor;

[0022] Extruded insulation: A two-layer, multi-stage extrusion process is adopted. First, vinyl resin material is extruded onto the surface of the stranded conductor to form an insulating buffer layer. Then, vinyl waterproof rubber and plastic material is extruded onto the insulating buffer layer to form an insulating layer. The thickness of the insulating layer is greater than the thickness of the insulating buffer layer. After the stranded conductor is extruded with the insulating buffer layer and the insulating material, the insulated wire core is obtained.

[0023] Stranded cable: Multiple insulated wire cores are stranded together according to a predetermined pitch ratio to form a cable core with a circular cross-section. During the stranding process, the gaps between the insulated wire cores are filled with filler cores of the same material but different specifications as the conductor insulation layer. The insulated wire cores and filler cores are in contact with each other and stranded together to form a cable. The remaining gaps between the insulated wire cores and filler cores in the cable core are filled with hydrophobic sealant.

[0024] Extruded inner lining: A layer of pure-grade EVA resin is extruded onto the outside of the cable core to form a waterproof inner lining. No rubber and plastic additives are added to the pure-grade EVA resin.

[0025] Braided armor and glue injection: Braided armor is applied to the outer surface of the waterproof inner lining to form a braided armor layer. This braided armor layer is made of tin-plated copper single wires woven on the outer surface of the waterproof inner lining. After the armor is woven, glue is injected between the tin-plated copper single wires to fill the gaps between the armor single wires with hydrophobic sealant. Then, EVA tape is wrapped around it.

[0026] An EVA tape is overlapped and wrapped around the outer surface of the woven armor layer to form a waterproof reinforcement layer. The waterproof reinforcement layer is penetrated and bonded by the injected hydrophobic sealant and forms an integral seal with the woven armor layer.

[0027] Extruded sheath layer and through-cabin buffer layer: The sheath layer and through-cabin buffer layer are extruded on the outer surface of the waterproof reinforcement layer through a double-layer co-extrusion process. Both are extruded using the same low-temperature resistant waterproof material to form a compatible and tight bond between them through co-extrusion. The through-cabin buffer layer constitutes the isolation layer between the cable sheath layer and the through-cabin penetrating component.

[0028] As an optional embodiment, the extrusion insulation process further includes:

[0029] Before extruding the insulation layer, a preheating treatment is performed, using a temperature of 60±10℃ to preheat the conductor and the insulation buffer layer to increase the adhesion between the conductor wire, the hydrophobic sealant, the insulation buffer layer, and the insulation layer.

[0030] As an optional embodiment, in the extrusion bonding of the sheath layer and the cabin buffer layer, the sheath layer serves as the inner layer and is made of a low-temperature resistant, waterproof chlorosulfonated polyethylene mixture, while the cabin buffer layer serves as the outer layer and is made of a high-density rigid compound with the same substrate as the sheath (i.e., chlorosulfonated polyethylene material) and a Shore A hardness of 90 to 95.

[0031] As an optional embodiment, the high-density hard compound may in particular be a commercially available chlorosulfonated polyethylene mixture doped with hardness-modifying fillers, such as a chlorosulfonated polyethylene mixture doped with nano-diatomite, to improve the hardness and toughness of the buffer layer.

[0032] Based on the above embodiments, the polar cryogenic marine cable proposed in this invention achieves longitudinal watertightness, low-temperature resistance, and corrosion resistance. It also features a pure-grade EVA resin waterproof inner liner extruded over the cable core and an additional transom protection layer outside the sheath. Through the compatibility between the transom protection layer and the outer sheath, the cable achieves resistance to -55°C, seawater resistance, and easy transom bonding. In low-temperature seawater environments, no plasticizers precipitate on the cable surface, and the vulcanization seal between the cable and the transom penetrations (accessories) does not delaminate. The transom buffer layer forms an isolation layer between the penetrations and the cable sheath. When rubber and plastic additives in the outer sheath precipitate in low-temperature and seawater environments, they remain within the buffer layer, preventing vulcanization seal delamination between the cable body structure and the penetrations, which would affect the bonding effect. This improves the sealing and bonding performance of the cable transom under seawater corrosion and extremely low-temperature environments, ensuring no water leakage or sheath displacement, and reducing and avoiding problems such as water leakage, air leakage, and seawater erosion caused by breakage, delamination, and separation between the transom cable and accessories.

[0033] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below may be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other. Furthermore, all combinations of the claimed subject matter are considered part of the inventive subject matter of this disclosure.

[0034] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0035] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings.

[0036] Figure 1a , 1b This is a schematic diagram illustrating the delamination between the low-temperature resistant cable and the penetration fitting during use in a cabin, leading to seal failure in the existing technology.

[0037] Figure 2 This is a schematic diagram of the structure of the polar cryogenic marine cable through the cabin according to an embodiment of the present invention. Detailed Implementation

[0038] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0039] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, which illustrate numerous illustrative embodiments. The embodiments of this disclosure are not necessarily intended to encompass all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed herein are not limited to any particular implementation. Furthermore, some aspects of the invention disclosed may be used alone or in any suitable combination with other aspects of the invention disclosed.

[0040] {Polar Low Temperature Resistant Marine Through-Cavity Cables}

[0041] Combination Figure 2 The polar cryogenic marine cable shown in the embodiment includes an insulated core consisting of a longitudinally water-blocking stranded conductor 1 and a conductor insulation layer 2, which is stranded together with a filler core 3 to form a longitudinally water-blocking cable core, and a waterproof inner lining layer 5, a braided armor layer 6, a waterproof reinforcement layer 7, a sheath layer 8, and a cabin buffer layer 9 designed layer by layer on the outer surface of the cable core.

[0042] Multiple insulated wire cores are twisted together according to a predetermined pitch ratio to form a circular cable core with a longitudinal water-blocking cross-section. During the cable core twisting process, the gaps between the insulated wire cores are filled with filler cores 3 of the same material but different specifications as the conductor insulation layer 2. The insulated wire cores and filler cores 3 are in contact with each other and twisted together to form a cable. The remaining gaps between the insulated wire cores and filler cores 3 in the cable core are filled with hydrophobic sealant 4 to form a longitudinal waterproof barrier. The cable core is tightly formed and is not easily deformed when subjected to external pressure.

[0043] In an embodiment of the present invention, the stranded conductor 1 is formed by stranding multiple single wires, for example, 1+6+12+6n... strands (n is the number of stranded layers) of tin-plated copper single wires of the same diameter are regularly stranded, and during the stranding process of the single wires, hydrophobic sealant is filled between the single wires so that the single wires achieve a stable longitudinal water-blocking effect.

[0044] The hydrophobic sealant is a hydrophobic adhesive material, which uses an elastomer composite conductive water adhesive. It has excellent adhesion to copper conductors and temperature cycle stability. During heating / cooling temperature fluctuations, it will not shrink rapidly or expand significantly. While achieving stable water blocking, it will not affect the conductor resistance and current carrying capacity.

[0045] A conductor insulation layer 2 is extruded onto the outer surface of the stranded conductor 1, forming an insulated core with the stranded conductor 1. The conductor insulation layer 2 is double-extruded, consisting of an insulating buffer layer 2-1 bonded to the stranded conductor 1 and the individual wires with a hydrophobic sealant, and an insulation layer 202 on the surface of the insulating buffer layer. The insulating buffer layer 2-1 is made of vinyl ester resin with an extrusion thickness of 0.2–0.3 mm. The insulation layer 2-2 is made of vinyl ester waterproof rubber-plastic material with an extrusion thickness of 0.3–0.5 mm.

[0046] In an optional embodiment, the insulating buffer layer and the insulating layer are co-extruded onto the conductor using an extrusion die to fill the gaps on the outside of the conductor, forming a dense and rounded layer.

[0047] A layer of pure-grade EVA resin is extruded over the cable core to form a waterproof inner liner 5, which then solidifies the cable core structure. In this embodiment of the invention, the pure-grade EVA resin used in the waterproof inner liner 5 is selected based solely on low-temperature performance and extrusion process performance, without considering electrical or physical-mechanical properties. Pure-grade EVA resin has excellent waterproof performance, does not absorb water, and effectively ensures waterproofing. Furthermore, because it does not contain any rubber or plastic additives, the inner liner exhibits excellent low-temperature resistance and will not leach out in low-temperature or seawater environments.

[0048] A braided armor layer 6 is formed on the outer surface of the waterproof inner lining layer 5. In an embodiment of the present invention, the braided armor layer 6 is woven with tin-plated copper single wires on the outer surface of the waterproof inner lining layer 5. After the armor is woven, adhesive is injected between the tin-plated copper single wires to fill the gaps between the armor single wires with hydrophobic sealant, and then EVA tape is wrapped around it.

[0049] A waterproof reinforcing layer 7 is formed by overlapping and wrapping an EVA tape over the woven armor layer 6. In embodiments of the present invention, the wrapping thickness of the waterproof reinforcing layer 7 is 0.2–0.3 mm, and the wrapping overlap rate is 10%–15%.

[0050] The waterproof reinforcement layer 7 is penetrated and bonded by the injected hydrophobic sealant, forming an integral seal with the woven armor layer 6.

[0051] Finally, a sheath layer 8 and a penetration buffer layer 9 are extruded onto the outer surface of the waterproof reinforcement layer 7 using a double-layer co-extrusion process. The sheath layer 8 and the penetration buffer layer 9 are made of low-temperature resistant waterproof material with the same substrate, so that they can be co-extruded to form a compatible and tight bond. The penetration buffer layer 9 constitutes the isolation layer between the cable sheath layer 8 and the penetration component.

[0052] In an optional embodiment, in the tight bonding of the sheath layer 8 and the penetration buffer layer 9, the sheath layer 8 serves as the inner layer and is made of a low-temperature resistant, waterproof chlorosulfonated polyethylene mixture, while the penetration buffer layer 9 serves as the outer layer and is made of a high-density hard compound with the same substrate as the sheath (i.e., chlorosulfonated polyethylene material) and a Shore A hardness of 90 to 95, thereby ensuring the compatibility between the two.

[0053] As an optional embodiment, the high-density hard compound may in particular be a commercially available chlorosulfonated polyethylene mixture doped with hardness-modifying fillers, such as a chlorosulfonated polyethylene mixture doped with nano-diatomite, to improve the hardness and toughness of the buffer layer.

[0054] In an embodiment of the present invention, the extrusion thickness of the cabin penetration buffer layer 9 is 0.3 to 0.4 mm. During extrusion, the maximum thickness of the outer layer is no more than 1.15 times the minimum thickness. If the layer is too thin, it is easily damaged during the passivation treatment of the surface during cabin penetration construction; if it is too thick, it will easily lead to difficulties in bending construction. Furthermore, the thickness of the sheath layer 8 is greater than the thickness of the cabin penetration buffer layer 9.

[0055] Therefore, the sheath layer and the penetration buffer layer are made of the same base material, exhibiting good compatibility. They can be tightly bonded together through double-layer co-extrusion, with the penetration buffer layer forming an isolation layer between the penetration component and the cable sheath. When rubber and plastic additives in the sheath precipitate in low-temperature and seawater environments, they remain within the buffer layer, preventing vulcanization and delamination between the cable and the penetration component, which would affect the bonding effect.

[0056] {Preparation method of polar cryogenic marine through-hull cable}

[0057] Based on the design of the polar cryogenic marine through-hull cable of the above embodiments, the preparation method, as an example, includes the following steps:

[0058] (1) Stranded conductor preparation: Multiple tin-plated copper single wires of the same diameter are regularly stranded and formed, and hydrophobic sealant is filled between the stranded single wires. The stranding pitch ratio is controlled at 10 to 15 times to prepare stranded conductor 1.

[0059] (2) Extrusion insulation: A double-layer extrusion process is adopted. First, vinyl resin material is extruded on the surface of stranded conductor 1 to form an insulating buffer layer. Then, vinyl waterproof rubber and plastic material is extruded on the insulating buffer layer to form an insulating layer. The thickness of the insulating layer is greater than the thickness of the insulating buffer layer. After the stranded conductor 1 is extruded with the insulating buffer layer and the insulating material, an insulated wire core is obtained.

[0060] (3) Stranding into a cable: Multiple insulated wire cores are stranded together according to a predetermined pitch ratio to form a cable core with a circular cross-section. During the stranding process, the gaps between the insulated wire cores are filled with filler cores 3 of the same material but different specifications as the conductor insulation layer. The insulated wire cores and filler cores 3 are in contact with each other and stranded together to form a cable. The remaining gaps between the insulated wire cores and filler cores 3 in the cable core are filled with hydrophobic sealant.

[0061] (4) Extruded inner lining layer: A layer of pure-grade EVA resin is extruded on the outside of the cable core to form a waterproof inner lining layer 5, wherein no rubber and plastic additives are added to the pure-grade EVA resin.

[0062] (5) Braided armor and glue injection: Braided armor is applied to the outer surface of the waterproof inner lining layer 5 to form a braided armor layer 6. The braided armor layer 6 is made of tin-plated copper single wires braided on the outer surface of the waterproof inner lining layer 5. After the armor is braided, glue is injected between the tin-plated copper single wires to fill the gaps of the armor single wires with hydrophobic sealant, and then EVA tape is wrapped around it.

[0063] (6) An EVA tape is overlapped and wrapped around the outer surface of the braided armor layer 6 to form a waterproof reinforcement layer 7. The wrapping thickness of the waterproof reinforcement layer 7 is 0.2-0.3 mm and the wrapping overlap rate is 10%-15%. The waterproof reinforcement layer 7 is penetrated and bonded by the injected hydrophobic sealant and forms an integral seal with the braided armor layer 6.

[0064] (7) Extruded sheath layer 8 and through-cabin buffer layer 9: The sheath layer 8 and through-cabin buffer layer 9 are extruded on the outer surface of the waterproof reinforcement layer 7 by a double-layer co-extrusion process, and the two are extruded with the same low-temperature resistant waterproof material to form a compatible and tight bond between them through co-extrusion. The through-cabin buffer layer 9 constitutes the isolation layer between the cable sheath layer 8 and the through-cabin penetrating component.

[0065] As an optional embodiment, the aforementioned extrusion insulation process further includes:

[0066] Before extruding the insulation layer, a preheating treatment is performed, using a temperature of 60±10℃ to preheat the conductor and the insulation buffer layer to increase the adhesion between the conductor wire, the hydrophobic sealant, the insulation buffer layer, and the insulation layer.

[0067] As an optional embodiment, in the extrusion bonding of the sheath layer 8 and the penetration buffer layer 9, the sheath layer 8 serves as the inner layer and is made of a low-temperature resistant, waterproof chlorosulfonated polyethylene mixture, while the penetration buffer layer 9 serves as the outer layer and is made of a chlorosulfonated polyethylene mixture doped with hardness-modified fillers, with a Shore A hardness of 90-95. Furthermore, the extrusion thickness of the penetration buffer layer 9 is 0.3-0.4 mm, and the maximum thickness of the outer layer during extrusion is not greater than 1.15 times the minimum thickness. Additionally, the thickness of the sheath layer 8 is greater than the thickness of the penetration buffer layer 9.

[0068] {Example 1}

[0069] The design of the polar cryogenic marine cable according to the foregoing embodiments of the present invention, as an example of the cable preparation method, includes the following steps one to seven.

[0070] Step 1: Conductor stranding

[0071] The same diameter tinned copper single wires are regularly stranded using 1+6+12+6n…… (n is the number of strands), and the single wires are filled with hydrophobic sealant.

[0072] The hydrophobic sealant is a hydrophobic material made from commercially available elastomeric composite water-based adhesive. It has excellent adhesion to copper conductors and resistance to temperature cycling. During heating / cooling temperature fluctuations, it will not shrink rapidly or expand significantly. While achieving stable water blocking, it will not affect the conductor resistance and current carrying capacity.

[0073] In this embodiment, the properties of the hydrophobic sealant are as follows:

[0074] Melt Flow Index (50±10)g / 10min@150℃ Processing temperature (180±10)℃ coefficient of thermal expansion ≤8％ High temperature thermal stability No dripping occurs at 150℃ for 24 hours. Low temperature stability Keeps soft at -45℃

[0075] The conductor sealing and injection is completed simultaneously during conductor stranding.

[0076] During the stranding process of the conductor wires, the conductor wires are stranded by a tube stranding machine. Before the single wires are formed into a conical shape and rotated into the stranding and merging mold by passing through the wire separator, a heated pressure plate unloading machine is used to heat and melt the hydrophobic sealant. The sealant is then pressed into the channel set on the top of the merging mold sleeve through a conveying hose, thus entering the mold sleeve's glue cavity and forming a glue pool. As the conductor continues to rotate forward into the glue cavity and merging mold, the molten hydrophobic sealant is pushed into the mold and continuously deposited on the single wire. The conductor continues to move forward through the sizing mold, causing the hydrophobic sealant to compactly fill the gaps between the stranded conductors.

[0077] During this process, closed-loop feedback can be provided to the pressure plate unloader and regulating valve through optical scanners and sensors to control the flow rate of hydrophobic sealant, so as to achieve full loading of the sealant cavity and ensure that the hydrophobic sealant always completely fills the conductor gap, forming a longitudinal waterproof barrier.

[0078] Step 2: Insulating buffer layer and insulating layer

[0079] To enhance the compactness, compressive strength, and reliability of the entire insulated conductor, an insulating buffer layer is designed between the insulation layer and the conductor. This buffer layer is co-extruded onto the conductor using an extrusion die, filling the gaps on the outside of the conductor and forming a dense, rounded layer.

[0080] The insulating buffer layer is made of high-purity vinyl resin, such as polyvinyl chloride (PVC) and polyethylene, with an extrusion thickness of (0.2~0.3) mm. The insulating layer is made of waterproof rubber and plastic material with the same substrate as the insulating buffer layer. During double-layer extrusion, the conductor is preheated at a temperature of (60±10)℃ for (8~10) hours to increase the adhesion between the conductor wire, hydrophobic sealant, insulating buffer layer and insulating layer.

[0081] Step 3: Cable Formation

[0082] Several insulated wire cores are twisted together at a ratio of (10±5) to form a cable. To avoid affecting structural stability by using a large amount of sealant to fill the large gaps between the wire cores, filler cores of different specifications made of the same material as the insulation are used to fill the gaps, and then hydrophobic sealant is injected. The insulated wire cores and filler cores are in contact with each other and are tightly formed, making them less prone to deformation under external pressure.

[0083] The cable-forming process is carried out on a cage stranding machine. Its glue injection process is similar to that of conductor glue injection. It can provide closed-loop feedback to the pressure plate unloading machine and regulating valve through optical scanners and sensors to control the flow of hydrophobic sealant to achieve full loading of the glue cavity, so that the hydrophobic sealant always completely fills the gaps and forms a longitudinal waterproof barrier.

[0084] Step 4: Extruding the inner lining layer

[0085] A layer of pure-grade EVA resin waterproof liner is extruded over the cable core to solidify the cable core structure. In embodiments of the present invention, the liner is designed with low-temperature performance and extrusion process performance in mind only, without considering electrical or physical-mechanical properties. EVA resin has excellent waterproof performance and does not absorb water, effectively ensuring waterproofing. Furthermore, since no rubber or plastic additives are added, the liner exhibits excellent low-temperature resistance and will not leach out in low-temperature or seawater environments.

[0086] Step 5, Armor Weaving: Tin-plated copper single wires are used for weaving. The diameter of the single wires, the weaving angle, and the weaving coverage comply with GJB 1916A-2022. Hydrophobic sealant is injected between the armor single wires using an automatic glue injection machine to achieve watertightness in the weaving gaps.

[0087] Step Six: Waterproof Reinforcement Layer

[0088] An EVA strip is wrapped around the outside of the armor. The strip is 0.2-0.3 mm thick and has an overlap rate of 10%-15%. It has excellent waterproof performance and does not absorb water. On the one hand, it is fully bonded to the sheath by high temperature melting at the extruder head during the extrusion process. On the other hand, it is bonded to the inner hydrophobic sealant to form an integral seal, effectively ensuring waterproof performance.

[0089] Step 7: Sheathing layer and penetration buffer layer

[0090] The sheath layer and the buffer layer are extruded together using a double-layer co-extrusion process. The inner layer is a low-temperature resistant, waterproof, chlorosulfonated polyethylene mixture; the outer layer is a high-density rigid compound with the same substrate as the sheath, a Shore A hardness of 90-95, and the same temperature resistance as the sheath, which can effectively prevent the diffusion of additives in the outer layer.

[0091] In embodiments of the present invention, based on the diffusion of rubber additives in the sheath, the extrusion thickness of the outer layer (i.e., the through-hull buffer layer) is designed to be (0.3-0.4) mm. During extrusion, the maximum thickness of the outer layer should not exceed 1.15 times the minimum thickness. If this layer is too thin, it is prone to damage during the passivation treatment of the through-hull construction surface; if it is too thick, it will easily lead to difficulties in bending construction. The sheath and the through-hull buffer layer are made of the same matrix material, exhibiting good compatibility. They can be tightly bonded together through double-layer co-extrusion. The through-hull buffer layer constitutes an isolation layer between the through-hole component and the cable sheath. When rubber and plastic additives in the sheath precipitate in low-temperature and seawater environments, they will remain within the buffer layer, preventing vulcanization and delamination between the cable and the through-hole component, thus avoiding affecting the bonding effect.

[0092] {Test Results}

[0093] (1) Sealing and penetration performance test after high and low temperature shock cycle

[0094] Take a 1.5m long cable and conduct a high and low temperature shock test according to the requirements of GJB 150.5A-2009 Part 5 on temperature shock test, with 30 cycles, including a high temperature of 65℃ (held for 30 minutes) and a low temperature of -55℃ (held for 30 minutes).

[0095] The sample was then fitted with the through-hole component and placed in a hydraulic pressure vessel. The solution was a 3.5% NaCl saline solution (GJB1916A-2022) at a temperature of (20±5)℃. The water pressure was increased to 6.75 MPa within 5 minutes and maintained for 24 hours. Next, the cable and sealing assembly were removed from the hydraulic pressure vessel and subjected to temperature cycling. The temperature cycle consisted of two parts: a temperature of (110±5)℃ for 24 hours and a subsequent temperature of (20±2)℃ for 24 hours, alternating for three cycles.

[0096] The pressure cycling test was repeated for 4 hours during the last 12 hours of the third 20°C duration. No water leakage occurred through the stuffing box, and the cable did not shift within the stuffing box. Three more temperature cycles were then performed, followed by a 4-hour pressure cycling test during the last 12 hours of the final 20°C duration. No water leakage occurred through the stuffing box, and the cable displacement within the stuffing box did not exceed 5 mm. During the test with a water pressure of 6.75 MPa, the cable did not leak water, and the sheath did not shift, meeting the requirements of GJB 1916A-2022.

[0097] (2) Sealing and penetration performance test after alternating water pressure

[0098] A 1.5m long cable was placed in a hydrostatic container after being fitted with a penetration fitting. The solution was a 3.5% NaCl saline solution (GJB 1916A-2022). An alternating pressure cyclic test was conducted at room temperature to simulate the reliability of the longitudinal watertight cable under water pressure changes caused by repeated surfacing and diving of deep-sea equipment. The product underwent 500 cycles of alternating water pressure from 0MPa to 6.75MPa to 0MPa, with each pressure holding time of 10 minutes. The cable and the penetration fitting remained tightly sealed, with no displacement of the penetration fitting and no water leakage at the seal. Furthermore, the cable did not leak and the sheath did not shift, meeting the requirements of GJB 1916A-2022.

[0099] (3) 90-day seawater immersion test

[0100] The cable was placed in seawater at room temperature for 90 days, with both ends exposed above the water surface. The seawater solution met the requirements of GJB 1916A-2022. There were no exudates on the outer surface of the cable, and the sheath had no cracks. The insulation resistance and withstand voltage met the specified requirements. Then, a 1.5m sample was taken for a longitudinal watertight test at 6.75MPa for 24 hours. The cable did not leak water and the sheath did not shift.

[0101] (4) Low temperature performance test

[0102] According to GJB 1916A-2022, the cable undergoes low-temperature bending, low-temperature operation, and low-temperature impact at -55℃, and no sheath cracks occur.

[0103] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A polar cryogenic marine through-hull cable, characterized in that, include: A stranded conductor (1) is formed by stranding multiple single wires together, and hydrophobic sealant is filled between the stranded single wires; A conductor insulation layer (2) is extruded on the outer surface of the stranded conductor (1), and the stranded conductor (1) and the conductor insulation layer (2) form an insulated core; A cable core with a circular cross-section is formed by twisting multiple insulated wire cores according to a predetermined pitch ratio. During the twisting process, the gaps between the insulated wire cores are filled with filler cores (3) of the same material but different specifications as the conductor insulation layer (2). The insulated wire cores and filler cores (3) are in contact with each other and twisted together to form a cable. The remaining gaps between the insulated wire cores and filler cores (3) in the cable core are filled with hydrophobic sealant (4). A waterproof inner lining layer made of pure EVA resin is extruded over the cable core of the cable (5); A woven armor is applied to the outer surface of the waterproof inner lining (5) to form a woven armor layer (6); EVA tape is overlapped and wrapped around the outer surface of the woven armor layer (6) to form a waterproof reinforcement layer (7); and A sheath layer (8) and a buffer layer (9) are sequentially formed on the outer surface of the waterproof reinforcement layer (7); The sheath layer (8) and the through-cabin buffer layer (9) are formed by double-layer co-extrusion process, and both have the same low-temperature waterproof material as the base material, so that they can be co-extruded to form a compatible and tight bond. The through-cabin buffer layer (9) constitutes the isolation layer between the cable sheath layer (8) and the through-cabin penetrating part.

2. The polar cryogenic marine through-cabin cable according to claim 1, characterized in that, In the combination of the sheath layer (8) and the cabin buffer layer (9), the sheath layer (8) serves as the inner layer and is made of a low-temperature resistant, waterproof, chlorosulfonated polyethylene mixture, while the cabin buffer layer (9) serves as the outer layer and is made of a chlorosulfonated polyethylene mixture doped with hardness-modified fillers, with a Shore A hardness of 90 to 95.

3. The polar cryogenic marine through-tank cable according to claim 1, characterized in that, The extrusion thickness of the cabin buffer layer (9) is (0.3~0.4) mm, and the thickness of the sheath layer (8) is greater than the thickness of the cabin buffer layer (9).

4. The polar cryogenic marine through-tank cable according to claim 1, characterized in that, The conductor insulation layer (2) is double-extruded, consisting of an insulating buffer layer bonded to the stranded conductor (1) and the single wire filled with hydrophobic sealant, and an insulating layer on the surface of the insulating buffer layer. The insulating buffer layer is made of vinyl resin material with an extrusion thickness of (0.2-0.3) mm, and the insulating layer is made of vinyl waterproof rubber and plastic material with an extrusion thickness of (0.3-0.5) mm.

5. The polar cryogenic marine through-tank cable according to claim 1, characterized in that, The waterproof inner lining (5) uses pure-grade EVA resin without the addition of rubber and plastic additives.

6. The polar cryogenic marine through-hull cable according to claim 1, characterized in that, The braided armor layer (6) is woven with tin-plated copper single wires on the outer surface of the waterproof inner lining layer (5). After the armor is woven, glue is injected between the tin-plated copper single wires to fill the gaps between the armor single wires with hydrophobic sealant, and then EVA tape is wrapped around it.

7. The polar cryogenic marine through-tank cable according to claim 6, characterized in that, A waterproof reinforcing layer (7) is formed by wrapping an EVA tape over the woven armor layer (6). The wrapping thickness of the waterproof reinforcing layer (7) is (0.2~0.3) mm, and the wrapping overlap rate is 10%~15%. The waterproof reinforcing layer (7) is penetrated and bonded by the injected hydrophobic sealant and forms an integral seal with the woven armor layer (6).

8. A method for preparing a polar cryogenic marine through-hull cable according to any one of claims 1-7, characterized in that, The preparation method includes: (1) Stranded conductor preparation: Multiple tin-plated copper single wires of the same diameter are regularly stranded and formed, and hydrophobic sealant is filled between the stranded single wires. The stranding pitch ratio is controlled at (10~15) times to prepare stranded conductor (1). (2) Extrusion insulation: A double-layer extrusion process is adopted. First, vinyl resin material is extruded on the surface of the stranded conductor (1) to form an insulating buffer layer. Then, vinyl waterproof rubber and plastic material is extruded on the insulating buffer layer to form an insulating layer. The thickness of the insulating layer is greater than the thickness of the insulating buffer layer. After the stranded conductor (1) is extruded with the insulating buffer layer and the insulating material, an insulated wire core is obtained. (3) Stranding into a cable: Multiple insulated wire cores are stranded together according to a predetermined pitch ratio to form a cable core with a circular cross-section. During the stranding process, the gaps between the insulated wire cores are filled with filler cores (3) of the same material but different specifications as the conductor insulation layer. The insulated wire cores and filler cores (3) are in contact with each other and stranded together to form a cable. The remaining gaps between the insulated wire cores and filler cores (3) in the cable core are filled with hydrophobic sealant. (4) Extruded inner lining layer: A layer of pure-grade EVA resin is extruded on the outside of the cable core to form a waterproof inner lining layer (5), wherein no rubber and plastic additives are added to the pure-grade EVA resin. (5) Braided armor and glue injection: Braided armor is applied to the outer surface of the waterproof inner lining (5) to form a braided armor layer (6). The braided armor layer (6) is woven with tin-plated copper single wires on the outer surface of the waterproof inner lining (5). After the armor is braided, glue is injected between the tin-plated copper single wires to fill the gaps of the armor single wires with hydrophobic sealant. Then, EVA tape is wrapped around it. (6) An EVA tape is overlapped and wrapped around the outer surface of the woven armor layer (6) to form a waterproof reinforcement layer (7). The wrapping thickness of the waterproof reinforcement layer (7) is (0.2~0.3) mm, and the wrapping overlap rate is 10%~15%. The waterproof reinforcement layer (7) is penetrated and bonded by the injected hydrophobic sealant and forms an integral seal with the woven armor layer (6). (7) Extruded sheath layer (8) and through-cabin buffer layer (9): The sheath layer (8) and through-cabin buffer layer (9) are extruded on the outer surface of the waterproof reinforcement layer (7) by a double-layer co-extrusion process. Both are extruded with the same low-temperature waterproof material to form a compatible and tight bond between them through co-extrusion. The through-cabin buffer layer (9) constitutes the isolation layer between the cable sheath layer (8) and the through-cabin penetrating part.

9. The method for preparing the polar cryogenic marine through-cabin cable according to claim 8, characterized in that, The extrusion insulation process also includes: Before extruding the insulation layer, a preheating treatment is performed. The conductor and the insulation buffer layer are preheated at a temperature of (60±10)℃ to increase the adhesion between the conductor wire, the hydrophobic sealant, the insulation buffer layer and the insulation layer.

10. The method for preparing the polar cryogenic marine through-cabin cable according to claim 8, characterized in that, In the extrusion bonding of the sheath layer (8) and the cabin buffer layer (9), the sheath layer (8) serves as the inner layer and is made of a low-temperature resistant and waterproof chlorosulfonated polyethylene mixture, while the cabin buffer layer (9) serves as the outer layer and is made of a chlorosulfonated polyethylene mixture doped with hardness-modified fillers, with a Shore A hardness of 90 to 95. The extrusion thickness of the cabin buffer layer (9) is (0.3 to 0.4) mm, and the thickness of the sheath layer (8) is greater than the thickness of the cabin buffer layer (9).

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