A neutral buoyancy cable for ROV

Abstract

The present invention relates to a neutral buoyancy cable for ROV, comprising an outer sheath, a foaming layer is arranged inside the outer sheath, a cable sheath is arranged inside the foaming layer, a plurality of core conductors are wrapped inside the cable sheath, and a filling layer is arranged in the gap between the cable sheath and the core conductors. In the present invention, by arranging the foaming layer and the filling layer inside the cable, the cable has neutral buoyancy, a breaking strength of 300KG, and is embedded with waterproof fibers to seal any leakage. The core of the cable includes a braided layer formed by Kevlar wire for strength and polyester fibers for space filling, and both fibers are impregnated with waterproof compounds to prevent any leakage caused by nicks or tears in the cable. It is not only light in weight and easy to float on the sea surface, but also has good tensile strength and flexural strength, and has great economic promotion value.

Description

Technical Field

[0001] The invention relates to the technical field of cables, in particular to a neutral buoyancy cable for ROV. Background Art

[0002] Wires and cables are wire products used to transmit electrical (magnetic) energy, information and realize electromagnetic energy conversion. Wires and cables in a broad sense are also referred to as cables. Cables in a narrow sense refer to insulated cables, which can be defined as: a collection of the following parts; one or more insulated cores, and their respective coatings, total protective layers and outer sheaths. Cables may also have additional uninsulated conductors.

[0003] In the existing technology, such as the Chinese patent with publication number CN104751991B, it discloses a cable, including a first sheath, a first shielding layer, a first cable core and a cable core coating layer, the first cable core includes a plurality of second cable cores, the second cable cores are rotationally twisted with each other, one of the second cable cores is arranged in the center, and the remaining second cable cores are evenly distributed around it, the cable core coating layer is rotated and coated around the first cable core in a clockwise direction, the first shielding layer is wrapped around the outer periphery of the cable core coating layer, and the first shielding layer, the first cable core and the cable core coating layer are all arranged inside the first sheath.

[0004] The above-mentioned prior art solutions have the following defects: Although the above-mentioned cables can reduce the interference signals generated by the data cable, separate the double shielding layers from each other, and avoid mutual influence of the shielding layers. However, they are similar to traditional cables in that they use copper as conductors and steel wire as tensile elements. Since the specific gravity of copper and steel wire is very large, if the cable is to float on the water, its insulation and sheath materials must be lighter than water and thicker, which not only increases the external size of the cable, but also wastes raw materials. In particular, cables with tensile elements made of steel wire will increase the weight of the cable a lot, and are not easy to bend, which affects the use function of the cable. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a neutral buoyancy cable for ROV, which is not only light in weight and easy to float on the sea surface, but also has good tensile strength and flexural strength, and has great economic promotion value.

[0006] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0007] A neutral buoyancy cable for ROV comprises an outer sheath, a foaming layer is arranged in the outer sheath, a cable wrapping layer is arranged in the foaming layer, a plurality of core conductors are wrapped in the cable wrapping layer, and a filling layer is arranged in the gap between the cable wrapping layer and the core conductors.

[0008] In a preferred example, the present invention can be further configured as follows: the cable wrapping layer is woven from a Kevlar braided layer and a non-woven fabric.

[0009] Through the above technical solution, the Kevlar braided layer is woven from multiple Kevlar lines, with a high strength of 20.92cN / dtex; line density: 1.667, heavier than water, sinking in water; resistant to cutting, good thermal stability, not melting at high temperatures, glass transition temperature of about 345℃; general bending performance, easy to form burrs when knotted; good tensile performance, elongation at break: 3.55%; resistant to common organic solvents and salt solutions, poor resistance to strong acids and strong alkalis; sensitive to ultraviolet rays, long-term exposure to sunlight, strength decay of about 40%; yellow appearance; relatively cheap price. It is woven into a cable wrapping layer with non-woven fabric, which not only improves the tensile and flexural strength of the cable, but also has a light weight and is easy to transport.

[0010] In a preferred example, the present invention can be further configured as follows: the outer sheath is a TPU sheath.

[0011] Through the above technical solution, the buoyant cable is used in harsh environments with a wide range of ambient temperature changes. It needs to have corrosion resistance, mildew resistance, oil resistance and moisture resistance. Therefore, the cable part that directly withstands this harsh environment - the outer sheath is an important part to ensure that the cable can achieve the above functions. Comparing the performance of materials such as PVC, PE, chlorosulfonated polyethylene (CSM) and various elastomers, polyurethane (TPU) was finally selected as the outer sheath material of the floating cable, which is the best choice. TPU is very balanced in density, corrosion resistance, mildew resistance, oil resistance and moisture resistance, and as a sheath material, its excellent mechanical strength and softness are unmatched by other materials. In addition, when the cable is connected, the sheath connection can be cold or hot, and the cable repair is also very convenient compared to rubber.

[0012] In a preferred example, the present invention can be further configured as follows: the foaming layer is a TPU foaming layer.

[0013] In a preferred example, the present invention can be further configured as follows: the filling layer is woven from water-blocking yarn and polyester fiber.

[0014] In a preferred example, the present invention can be further configured as follows: the core conductor is a bare copper or tinned copper wire multi-strand twisted conductor, and the gaps in the tinned copper wire multi-strand twisted conductor are filled with a water-blocking agent.

[0015] Through the above technical solution, the conductor adopts the 5th category tinned copper wire stranded conductor that complies with GB / T3956-2008. After twisting, the conductor is round, which effectively ensures the stability of power transmission and the high flexibility of the core. The single wire joint is cold welded and anti-corrosion treatment is performed at the joint; at the same time, a special water-blocking agent is filled in the gap of the twisted conductor to make the twisted conductor form a stable whole, which can prevent water from corroding the conductor and affecting the transmission performance and cable life.

[0016] In a preferred example, the present invention can be further configured as follows: the core conductor is wrapped with an insulating layer, and the insulating layer is a thermoplastic rubber material or PE polyethylene with EPDM rubber and polypropylene as the base material and vulcanized.

[0017] Through the above technical solutions, the insulating material is an important component of the cable. From the perspective of insulation performance, the selection range is relatively wide. But for buoyant cables, the selection of insulating materials is more characteristic: first, it must be soft and easy to bend; second, the density should be as small as possible to ensure buoyancy; third, it has good processing performance. Through the performance analysis of soft polyvinyl chloride (PVC), cross-linked polyethylene (XLPE), ethylene propylene diene monomer (EPDM), etc., none of them are suitable. After comparing and testing new materials at home and abroad, thermoplastic rubber materials (TPV) or PE polyethylene with ethylene propylene diene monomer (EPDM) and polypropylene (PP) as the base material and vulcanized are more suitable.

[0018] The remarkable features of thermoplastic rubber material (TPV) are excellent electrical properties, low density, good mechanical properties, easy processing, and recyclability. It is an ideal insulation material for floating cables. This material can also be widely used in other cable products. The insulation layer is made of ultraviolet radiation cross-linked polyolefin material with low material density, heat resistance and good flexibility. The insulation is tightly wrapped outside the conductor and cross-linked by ultraviolet radiation. After cooling, the insulation has good mechanical properties and electrical insulation properties.

[0019] In a preferred example, the present invention can be further configured as follows: a protective layer is provided on the outside of the outer sheath, and a plurality of elastic plastic parts in a “>” shape are fixedly connected between the protective layer and the outer sheath.

[0020] Through the above technical scheme, the protective layer is a flame-retardant, flexible polyether polyurethane elastomer (polyether polyurethane elastomer has excellent hydrolysis resistance and waterproof penetration) material, which is produced by semi-extrusion, round and non-eccentric. Among them, the elastic plastic part in the shape of “>” can be deformed in the first time when the cable is bent, avoiding damage to the outer conductor and inner conductor inside the cable, greatly improving the anti-bending performance of the buoyant cable. And due to the special working environment of the buoyant cable, it needs to be suspended on the water surface in most cases, and some fish will gnaw the cable, causing damage to the cable. However, the elastic plastic part separates the protective layer from the outer sheath to form a gap. When the fish bites the cable, the teeth will be stuck on the elastic plastic part, and the elastic plastic part will be deformed at the same time, thereby effectively avoiding damage to the core conductor.

[0021] In summary, the present invention includes at least one of the following beneficial technical effects:

[0022] 1. The present invention provides a neutral buoyancy, a breaking strength of 300KG, and is embedded with waterproof fibers to seal any leaks by arranging a foaming layer and a filling layer inside the cable. The rope has a diameter of 6.0 mm, which is much thinner than most ROV tethers. The core of the cable contains a braided layer formed by Kevlar wire for strength and polyester fiber for space filling, both of which are impregnated with waterproof compounds to prevent any leakage caused by nicks or tears in the cable. It is not only light in weight and easy to float on the sea, but also has good tensile strength and flexural strength, and has great economic promotion value.

[0023] 2. The protective layer is made of flame-retardant and flexible polyether polyurethane elastomer (polyether polyurethane elastomer has excellent hydrolysis resistance and can resist water penetration) material, which is produced by semi-extrusion, round and non-eccentric. Among them, the elastic plastic part in the shape of “>” can be deformed at the first time when the cable is bent, avoiding damage to the outer conductor and inner conductor inside the cable, greatly improving the anti-bending performance of the buoyant cable. And due to the special working environment of the buoyant cable, it needs to be suspended on the water surface in most cases, and some fish will gnaw on the cable, causing damage to the cable. However, the elastic plastic part separates the protective layer from the outer sheath to form a gap. When the fish bites the cable, its teeth will be stuck on the elastic plastic part, and the elastic plastic part will be deformed at the same time, thereby effectively avoiding damage to the core conductor. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a cross-sectional view of the first embodiment.

[0025] Figure 2 This is a cross-sectional view of the second embodiment.

[0026] Figure numerals: 1, outer sheath; 2, foaming layer; 3, cable wrapping layer; 31, Kevlar braided layer; 32, non-woven fabric; 4, core conductor 5, filling layer; 6, insulation layer; 7, protective layer; 8, elastic plastic part. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application; obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application without making creative work are within the scope of protection of the present application.

[0028] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0029] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "provided with", "set / connected", "connected", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] Embodiment 1:

[0031] Reference Figure 1 , which is a neutral buoyancy cable for ROV disclosed in the present invention, comprises an outer sheath 1, a foaming layer 2 is arranged in the outer sheath 1, a cable wrapping layer 3 is arranged in the foaming layer 2, a plurality of core conductors 4 are wrapped in the cable wrapping layer 3, and a filling layer 5 is arranged in the gap between the cable wrapping layer 3 and the core conductor 4.

[0032] The cable sheath 3 is woven from a Kevlar braided layer 31 and a non-woven fabric 32. The Kevlar braided layer 31 is woven from a plurality of Kevlar lines, and has a high strength of 20.92 cN / dtex; a line density of 1.667, heavier than water, and sinks in water; it is resistant to cutting, has good thermal stability, does not melt at high temperatures, and has a glass transition temperature of about 345°C; it has average bending performance, and knots are prone to forming burrs; it has good tensile performance, and its elongation at break is 3.55%; it is resistant to common organic solvents and salt solutions, but poorly resistant to strong acids and alkalis; it is sensitive to ultraviolet rays, and its strength decays by about 40% after long-term exposure to sunlight; it has a yellow appearance; and it is relatively cheap. It is woven into the cable sheath 3 with the non-woven fabric 32, which not only improves the tensile and flexural strength of the cable, but also has a light weight and is easy to transport.

[0033] The outer sheath 1 is a TPU sheath. The buoyant cable is used in a harsh environment with a wide range of ambient temperature changes. It needs to have corrosion resistance, mold resistance, oil resistance, and moisture resistance. Therefore, the cable directly bears this harsh environment - the outer sheath 1 is an important part to ensure that the cable can achieve the above functions. Comparing the performance of materials such as PVC, PE, chlorosulfonated polyethylene (CSM) and various elastomers, polyurethane (TPU) is finally selected as the material for the outer sheath 1 of the floating cable, which is the best choice.

[0034] TPU is well balanced in density, corrosion resistance, mildew resistance, oil resistance and moisture resistance, and as a sheath material, its excellent mechanical strength and softness are unmatched by other materials. In addition, when the cable is connected, the sheath connection can be cold or hot, and the cable repair is also very convenient compared to rubber.

[0035] The foaming layer 2 is a TPU foaming layer, and the filling layer 5 is woven from water-blocking yarn and polyester fiber. The core conductor 4 is a tinned copper wire stranded conductor, and the gaps of the tinned copper wire stranded conductor are filled with a water-blocking agent.

[0036] The conductor is a Class 5 tinned copper wire stranded conductor that complies with GB / T3956-2008. After stranding, the conductor is round, effectively ensuring the stability of power transmission and the high flexibility of the core. The single-wire joint is cold-welded and anti-corrosion treatment is performed at the joint; at the same time, a special water-blocking agent is filled in the gap between the stranded conductors to form a stable whole, which can prevent water from corroding the conductor and affecting the transmission performance and cable life.

[0037] Since the core conductor 4 is made of copper, the density of metal copper is relatively high (density is 8.9g / cm3). In order to ensure that the cable overcomes its own weight and floats on the water surface, a foaming layer 2 is added to the cable to adjust the overall density of the cable. The foaming layer 2 adopts a foam + skin structure and is produced by a double-layer simultaneous extrusion process. The CO2 physical foaming of thermoplastic elastomer (TPE) is adopted, the foaming degree is about 70%, and the density of the foaming layer 2 is not more than 0.3g / cm3. The thickness of the foaming layer 2 is adjusted according to the weight of the cable structure so that the overall density of the cable is 0.9 or less of the water density.

[0038] The core conductor 4 is wrapped with an insulating layer 6, which is a thermoplastic rubber material or PE polyethylene with EPDM and polypropylene as the base material and vulcanized. The insulating material is an important component of the cable. From the perspective of insulation performance, the selection range is relatively wide. But as far as buoyancy cables are concerned, the selection of insulating materials is more special: first, it must be soft and easy to bend; second, the density should be as small as possible to ensure buoyancy; third, it has good processing performance. Through performance analysis of soft polyvinyl chloride (PVC), cross-linked polyethylene (XLPE), ethylene propylene diene monomer rubber (EPDM), etc., none of them are suitable. After comparison and testing of new materials at home and abroad, thermoplastic rubber materials (TPV) or PE polyethylene with EPDM and polypropylene (PP) as the base material and vulcanized are more suitable.

[0039] The remarkable features of thermoplastic rubber material (TPV) are excellent electrical properties, low density, good mechanical properties, easy processing, and recyclability. It is an ideal insulation material for floating cables. This material can also be widely used in other cable products. The insulation layer 6 is made of ultraviolet radiation cross-linked polyolefin material with low material density, heat resistance, and good flexibility. The insulation is tightly wrapped outside the conductor and cross-linked by ultraviolet radiation. After the insulation is cooled, it has good mechanical properties and electrical insulation properties.

[0040] Embodiment 2:

[0041] Reference Figure 2 , a neutral buoyancy cable for ROV, which is different from the first embodiment in that a protective layer 7 is provided on the outside of the outer sheath 1, and a plurality of elastic plastic parts 8 in the shape of ">" are fixedly connected between the protective layer 7 and the outer sheath 1. The protective layer 7 is made of a flame-retardant and flexible polyether polyurethane elastomer (polyether polyurethane elastomer has excellent hydrolysis resistance and can resist water penetration), is produced by semi-extrusion, is rounded, and has no eccentricity.

[0042] Among them, the elastic plastic part 8 in the shape of “>” can be deformed immediately when the cable is bent, avoiding damage to the outer conductor 42 and the inner conductor 41 inside the cable, greatly improving the anti-bending performance of the buoyant cable. In addition, due to the special working environment of the buoyant cable, it needs to be suspended on the water surface in most cases, and some fish will gnaw the cable, causing damage to the cable. However, the elastic plastic part 8 separates the protective layer 7 from the outer sheath 1 to form a gap. When the fish bites the cable, its teeth will be stuck on the elastic plastic part 8, and the elastic plastic part 8 will be deformed at the same time, thereby effectively avoiding damage to the core conductor 4.

[0043] The implementation principle of this embodiment is as follows: In the present invention, a foaming layer 2 and a filling layer 5 are arranged inside the cable to make it neutrally buoyant, have a breaking strength of 300KG, and be embedded with waterproof fibers to seal any leakage. The diameter of the rope is 6.0 mm, which is much thinner than most ROV tethers. The core of the cable contains a braided layer formed by Kevlar wire for strength and polyester fiber for space filling. Both fibers are impregnated with waterproof compounds to prevent any leakage caused by nicks or tears in the cable. It is not only light in weight and easy to float on the sea, but also has good tensile strength and flexural strength, and has great economic promotion value.

[0044] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A neutral buoyancy cable for ROV, comprising an outer sheath (1), characterized in that: The outer sheath (1) is provided with a foaming layer (2), the foaming layer (2) is provided with a cable wrapping layer (3), the cable wrapping layer (3) wraps a plurality of wire core conductors (4), and a filling layer (5) is provided in the gap between the cable wrapping layer (3) and the wire core conductors (4); A protective layer (7) is arranged on the outside of the outer sheath (1), and a plurality of elastic plastic parts (8) in a "">" shape are fixedly connected between the protective layer (7) and the outer sheath (1).

2. A neutral buoyancy cable for ROV according to claim 1, characterized in that: The cable wrapping layer (3) is woven from a Kevlar braided layer (31) and a non-woven fabric (32).

3. A neutral buoyancy cable for ROV according to claim 1, characterized in that: The outer sheath (1) is a TPU sheath.

4. A neutral buoyancy cable for ROV according to claim 1, characterized in that: The foaming layer (2) is a TPU foaming layer.

5. The neutral buoyancy cable for ROV according to claim 1, characterized in that: The filling layer (5) is woven from water-blocking yarn and polyester fibers.

6. A neutral buoyancy cable for ROV according to claim 1, characterized in that: The core conductor is a bare copper or tinned copper wire stranded conductor, and the gaps of the tinned copper wire stranded conductor are filled with a water-blocking agent.

7. A neutral buoyancy cable for ROV according to claim 1, characterized in that: The core conductor (4) is wrapped with an insulating layer (6), and the insulating layer (6) is a thermoplastic rubber material or PE polyethylene with EPDM rubber and polypropylene as the base material and vulcanized.

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