Axial tensile-resistant water-blocking cable

Abstract

The present invention proposes an axially tensile-resistant water-blocking cable, which relates to the technical field of water-blocking cables. The present invention spirally twists the cable core on a central tensile-resistant bearing unit, and uses the central tensile-resistant bearing unit to bear the main tensile force. Due to the winding method of the cable core, when subjected to tension, the cable core can squeeze the central tensile-resistant bearing unit toward the center in exchange for a certain elongation buffer space to avoid conductor breakage. At the same time, the extrusion force exceeding a specified value is used to squeeze and rupture the liquid foaming agent capsules in the central tensile-resistant bearing unit, so that the first foaming agent therein is combined with the second foaming agent in the twisted gap of the cable core through the woven central tensile-resistant bearing unit to produce a large amount of foam colloid, which pressurizes and seals high stress areas of the cable where water leakage may occur, thereby realizing active response to water blocking based on local stress mutations. Compared with traditional passive water blocking technology, the response speed is faster and the water blocking effect is better.

Description

Technical Field

[0001] The present invention relates to the technical field of water-blocking cables, and in particular to an axially tensile-resistant water-blocking cable. Background Art

[0002] Water-blocking cable is a type of cable with a special structure and material design that can effectively prevent moisture from penetrating into the cable, thereby ensuring the stability of power or signal transmission. Its core function is to prevent water intrusion through physical or chemical means. It is suitable for use in humid and high-humidity environments such as offshore wind power cables and mining towing cables.

[0003] Traditional water-blocking cables use passive water-blocking technology, such as water-blocking powder and water-blocking tape that absorb and expand due to water. These technologies have to wait for water to penetrate a portion of the cable before they can take effect. This technology has severe hysteresis and makes it difficult to actively block moisture. At the same time, existing cables used for marine wind power cables, mining towing cables, etc., due to the protection of steel belt armor, their failure due to water immersion is mostly not caused by sharp cuts, but by rupture of the waterproof layer caused by high tension or local extrusion stress. Traditional physical water-blocking layers are also prone to rupture when the cable is pulled or locally squeezed, which makes its water-blocking ability ineffective and leads to unstable water-blocking effect. Summary of the Invention

[0004] The object of the present invention is to provide an axially tensile-resistant water-blocking cable to solve the problem that the traditional cable technology proposed in the above background has serious hysteresis and unstable water-blocking effect.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is an axial tensile-resistant water-blocking cable, including: a central tensile-resistant bearing unit, the central tensile-resistant bearing unit is woven from high-strength metal wire; a hollow tubular structure is arranged in the central tensile-resistant bearing unit, the central tensile-resistant bearing unit is filled with liquid foaming agent capsules, and the liquid foaming agent capsules are filled with a first foaming agent; the central tensile-resistant bearing unit is wrapped with a spirally twisted wire core group, the spirally twisted wire core group includes a cable core, the cable core is provided with two or more strands, and is wound around the outside of the central tensile-resistant bearing unit in a precise spiral twisted manner; the outside of the spirally twisted wire core group is wrapped with a gradient composite water-blocking layer, the gradient composite water-blocking layer is provided with a water-blocking filling layer, the water-blocking filling layer is composed of a second foaming agent, the second foaming agent contains a water-absorbing resin, and the water-blocking filling layer is filled in the gaps of the spirally twisted wire core group; the outside of the gradient composite water-blocking layer is wrapped with a spiral armored protective layer, the spiral armored protective layer is formed by spirally winding a steel belt.

[0006] In one example, the liquid foaming agent capsule is sealed with a three-layer composite of polyester plastic film, aluminum foil film and polyethylene film.

[0007] In one example, the twist pitch of the helically stranded core group is 8-10 times the cable core diameter.

[0008] In one example, the cable core includes a conductor core and an insulation coating layer, wherein the insulation coating layer is wrapped around the outside of the conductor core.

[0009] In one example, the gradient composite water-blocking layer includes an outer side of the basic water-blocking layer, providing basic physical water-blocking protection function.

[0010] In one example, the gradient composite water-blocking layer includes a stress enhancement layer, which uses a rubber elastic constraint ring. The stress enhancement layer is evenly spaced outside the spirally twisted wire core group to limit foam diffusion and increase the foam pressure in the area.

[0011] In one example, the spiral armored protective layer uses 0.25mm thick galvanized steel strip, which is wrapped with a spiral angle of 45°±3°, and the wrapping gap is less than 0.25mm. The outside of the spiral armored protective layer is covered with a 0.35mm thick polyethylene anti-corrosion layer, which has strong compressive resistance. The compressive strength has been tested to be ≥55MPa, which can effectively resist radial extrusion and sharp cutting, provide reliable protection for the internal gradient composite water-blocking layer, and at the same time increase the overall tensile strength of the cable by 20% to 25%.

[0012] In one example, the first foaming agent component is: 90% low-viscosity isocyanate prepolymer and 10% ethylene glycol butyl ether; the second foaming agent component is: 45% polyether polyol powder, 20% sodium bicarbonate, 5% triethylenediamine and 30% water-absorbent resin, wherein the particle size of the polyether polyol powder is 50-80μm, and the surface of the triethylenediamine powder is coated with a 0.1μm zinc stearate hydrophobic layer; the core advantages are: fast reaction speed, can be cured within 90 seconds, expansion multiples of 15-20 times, bonding strength with metal and rubber substrates of 1.5-2.0MPa, and moderate cost.

[0013] In one example, the first foaming agent component is hydrogenated silicone oil; the second foaming agent component is 95% vinyl silicone oil and 5% fumed silica, with 2000ppm of platinum catalyst added to the vinyl silicone oil; its core advantages are: temperature resistance range of -60℃~200℃, water absorption rate of <0.1%, stable performance in long-term seawater immersion, and good biocompatibility; limitations: expansion multiple of 5-8 times, requiring additional physical foaming agents, high cost of about 500 yuan / kg, and requiring special mixing equipment.

[0014] In one example, the first foaming agent component is an isocyanate prepolymer; the second foaming agent component is: 85% amino polyether and 15% dichloromethane; its core advantages are: extremely fast reaction, can be cured within 30 seconds, compressive strength of 1.0-1.5MPa, suitable for high-pressure scenarios with water depth ≥100m; limitations: high requirements for substrate surface treatment, high brittleness after curing, and elongation at break ≤150%.

[0015] Compared with the prior art, the beneficial effects of the present invention include: an axially tensile-resistant water-blocking cable proposed in the present invention, which spirally twists the cable core on a central tensile-resistant bearing unit, and uses the central tensile-resistant bearing unit to bear the main tensile force. Due to its winding method, when the cable core is subjected to tension, the cable core can squeeze the central tensile-resistant bearing unit toward the center in exchange for a certain elongation buffer space to avoid conductor breakage. At the same time, the extrusion force exceeding the specified value is used to capsule the liquid foaming agent in the central tensile-resistant bearing unit, so that the first foaming agent therein is combined with the second foaming agent in the twisted gap of the cable core through the woven central tensile-resistant bearing unit to produce a large amount of foam colloid, which pressurizes and seals high-stress areas of the cable where water leakage may occur, thereby realizing active response to water blocking based on local stress mutations. Compared with traditional passive water blocking technology, the response speed is faster and the water blocking effect is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The disclosure of the present invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components. Among them: Figure 1 The figure schematically shows a layered cross-sectional structure diagram of an axially tensile-resistant water-blocking cable proposed according to one embodiment of the present invention.

[0017] Numbers in the figure: 1. Central tensile bearing unit; 2. Liquid foaming agent capsule; 3. Spiral twisted wire core group; 301. Cable core; 3011. Conductor core; 3012. Insulation coating; 4. Gradient composite water-blocking layer; 401. Basic water-blocking layer; 402. Water-blocking filling layer; 403. Stress enhancement layer; 5. Spiral armor protection layer; 501. Polyethylene anti-corrosion layer. DETAILED DESCRIPTION

[0018] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the entire invention or as a limitation or restriction of the technical solution of the present invention.

[0019] According to the embodiment of the present invention, Figure 1An axially tensile-resistant water-blocking cable comprises a central tensile-resistant bearing unit 1, a liquid foaming agent capsule 2, a spirally twisted wire core group 3, a gradient composite water-blocking layer 4 and a spiral armored protective layer 5.

[0020] 1. The central tensile load-bearing unit 1 is woven from high-strength metal wires. 0.3mm diameter stainless steel wire is selected and formed using a double-helix cross-weaving process. The weaving density is strictly controlled at ≥85%. The interior of the central tensile load-bearing unit 1 constructs a hollow tubular structure with an inner diameter in the range of 4-8mm.

[0021] 2. The central tensile bearing unit 1 is filled with a liquid foaming agent capsule 2 sealed by a PETG / AL / PE three-layer composite film, and the liquid foaming agent capsule 2 is filled with a first foaming agent.

[0022] 3. The central tensile load-bearing unit 1 is wrapped with a spirally stranded core assembly 3. This spirally stranded core assembly 3 consists of two or more cable cores 301, twisted in a precise spiral, wrapped around the central tensile load-bearing unit 1. The twist pitch is 8-10 times the diameter of the cable core 301. Cable core 301 consists of a conductor core 3011 and an insulating sheath 3012 surrounding the conductor core 3011. The conductor core 3011 can optionally be a single-core or multi-stranded conductor, made of highly conductive tinned copper or aluminum with a tested conductivity of no less than 97% IACS. The insulating sheath 3012 can optionally be made of cross-linked polyethylene or ethylene propylene rubber, with a thickness ranging from 0.6 to 1.2 mm. It has excellent temperature resistance, an operating temperature range of -40°C to 120°C, and a breakdown voltage of ≥30 kV / mm.

[0023] Fourth, a gradient composite water-blocking layer 4 is provided outside the spirally twisted wire core group 3. The gradient composite water-blocking layer 4 tightly wraps around the outside of the spirally twisted wire core group 3 and is designed to have a thickness of 1.8-2.2 mm. The gradient composite water-blocking layer 4 is composed of the following multi-layer structure: Base water-blocking layer 401: Utilizing a highly elastic butyl rubber elastomer with a Shore A hardness of 55-60, it provides basic physical water-blocking protection. Water-blocking filling layer 402: A powdered second foaming agent is evenly filled within the gaps of the spirally twisted wire core group 3. The second foaming agent is a mixture of a foaming agent component and a water-absorbing resin. The filling density of the water-blocking filling layer 402 is maintained at 650-750 g / m³, and the expansion rate of the water-blocking filling layer 402 within 5 minutes after contact with water is ≥85%. Stress enhancement layer 403; stress enhancement layer 403 adopts EPDM rubber elastic restraint ring with a thickness of 1mm, which is evenly spaced and sleeved on the outside of the spiral stranded wire core group 3, which can effectively limit the foam diffusion range and increase the foam pressure in this area by 60%.

[0024] 5. The gradient composite water-blocking layer 4 is wrapped with a spiral armored protective layer 5. The spiral armored protective layer 5 is made of high-quality galvanized steel strip with a thickness of 0.25 mm and is wrapped with a spiral angle of 45°±3°. The wrapping overlap rate is strictly guaranteed to be ≥18%, and the wrapping gap is precisely controlled to be ≤0.25 mm. The spiral armored protective layer 5 is covered with a 0.35 mm thick polyethylene anti-corrosion layer 501 on the outside, which has strong compressive performance. The compressive strength has been tested to be ≥55 MPa, which can effectively resist radial extrusion and sharp cutting, provide reliable protection for the internal gradient composite water-blocking layer, and at the same time increase the overall tensile strength of the cable by 20% to 25%.

[0025] Example 1: System A: two-component polyurethane foaming system.

[0026] The first foaming agent: 90% low-viscosity isocyanate prepolymer with an NCO content of 22% to 25%, 10% ethylene glycol butyl ether as a reactive diluent, and a viscosity of 180-220 mPa•s (25°C).

[0027] The second foaming agent is composed of 45% polyether polyol powder with a hydroxyl value of 300-400 mgKOH / g and a particle size of 50-80 μm; 20% sodium bicarbonate; 5% triethylenediamine powder as an additive, the surface of which is coated with a 0.1 μm zinc stearate hydrophobic layer; and 30% water-absorbent resin, the resin is SAP, with a particle size of 100-200 μm, a water absorption rate of 500-1000 times, and a surface coated with a 0.1 μm zinc stearate hydrophobic layer.

[0028] Core advantages: fast reaction speed, can be cured within 90 seconds, expansion ratio is 15-20 times, bonding strength with metal and rubber substrates is 1.5-2.0MPa, and the cost is moderate, about 80 yuan / kg.

[0029] Table 1 is a summary of key performance experimental data:

[0030]

[0031] Example 2: System B: two-component silicone rubber foaming system.

[0032] The first foaming agent: hydrogen-containing silicone oil, with a hydrogen content of 0.15% to 0.2% and a viscosity of 300-500 mPa•s.

[0033] Secondary foaming agent: 95% vinyl silicone oil, vinyl content 0.1% to 0.15%, with 2000ppm platinum catalyst. 5% fumed silica as a thickener.

[0034] Core advantages: Temperature resistance range of -60°C to 200°C, water absorption rate <0.1%, stable performance even after long-term seawater immersion, and good biocompatibility. Limitations: Expansion ratio of 5-8 times, requiring additional physical foaming agents, high cost (approximately 500 yuan / kg), and requiring specialized mixing equipment.

[0035] Table 2 is a summary of key performance experimental data:

[0036]

[0037] Example 3: System C: two-component polyurea foaming system.

[0038] First foaming agent: isocyanate prepolymer, NCO content 30% to 35%, viscosity ≤100mPa•s.

[0039] Secondary foaming agent: 85% amino polyether, amine value 200-250mgKOH / g. 15% dichloromethane, as a physical foaming agent.

[0040] Core Advantages: Extremely fast reaction, curing within 30 seconds, compressive strength of 1.0-1.5 MPa, suitable for high-pressure scenarios at water depths ≥ 100 m. Limitations: Requires high surface preparation of the substrate, exhibits high brittleness after curing, and has an elongation at break of ≤ 150%.

[0041] Table 3 is a summary of key performance experimental data:

[0042]

[0043] Working principle: When an axially tensile-resistant water-blocking cable of the present invention encounters excessive tension, the cable core 301 spirally twisted and wound around the outside of the central tensile-resistant bearing unit 1 will slide, squeezing the central tensile-resistant bearing unit 1, so that the cable core 301 can be slightly stretched and retracted, allowing the central tensile-resistant bearing unit 1 to bear the main tension, thereby avoiding the breakage of the conductor core 3011.

[0044] When the tension is too great, the base water-blocking layer 401 is prone to rupture. At the same time, the squeezing force of the cable core 301 will crush the liquid foaming agent capsule 2 in the central tensile bearing unit 1, causing the first foaming agent stored in the liquid foaming agent capsule 2 to leak. The central tensile bearing unit 1 is woven from high-strength metal wire and has poor water resistance. The first foaming agent can pass through the central tensile bearing unit 1 and combine with the second foaming agent to produce a large amount of colloidal foam, blocking possible water leakage channels. The water-absorbing resin in the second foaming agent can quickly absorb water and expand, thereby removing the leaked water, which can not only prevent radial water leakage, but also prevent water from diffusing axially. At the same time, the setting of the stress enhancement layer 403 can block the axial diffusion path of the foam to a certain extent, causing the foam pressure in the local area to rise sharply. The internal high pressure can resist the external water pressure, further preventing external water leakage and significantly improving the waterproof depth of the cable.

[0045] The technical scope of the present invention is not limited to the contents of the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of ​​the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. An axially tensile-resistant water-blocking cable, characterized in that: include: A central tensile bearing unit, the central tensile bearing unit is woven from metal wires; a hollow tubular structure is provided in the central tensile bearing unit, the central tensile bearing unit is filled with liquid foaming agent capsules, and the liquid foaming agent capsules are filled with a first foaming agent; the central tensile bearing unit is wrapped with a spirally twisted wire core group, the spirally twisted wire core group includes a cable core, the cable core is provided with two or more strands, and the cable core is wound around the outside of the central tensile bearing unit in a spirally twisted manner; the outside of the spirally twisted wire core group is wrapped with a gradient composite water-blocking layer, a water-blocking filling layer is provided in the gradient composite water-blocking layer, the water-blocking filling layer is composed of a second foaming agent, the second foaming agent contains a water-absorbing resin, and the water-blocking filling layer is filled in the gaps of the spirally twisted wire core group; the outside of the gradient composite water-blocking layer is wrapped with a spiral armored protective layer, and the spiral armored protective layer is formed by spirally winding a steel belt.

2. The axially tensile-resistant water-blocking cable according to claim 1, characterized in that: The liquid foaming agent capsule is sealed by a three-layer composite of polyester plastic film, aluminum foil film and polyethylene film.

3. The axially tensile-resistant water-blocking cable according to claim 1, characterized in that: The twisting pitch of the spirally stranded wire core group is 8-10 times the cable core diameter.

4. The axially tensile-resistant water-blocking cable according to claim 1, characterized in that: The cable core comprises a conductor core and an insulating coating layer, wherein the insulating coating layer is wrapped around the outer side of the conductor core.

5. The axially tensile-resistant water-blocking cable according to claim 1, characterized in that: The gradient composite water-blocking layer includes the outer side of the basic water-blocking layer.

6. The axially tensile-resistant water-blocking cable according to claim 5, characterized in that: The gradient composite water-blocking layer comprises a stress enhancement layer, the stress enhancement layer adopts a rubber elastic constraint ring, and the stress enhancement layer is sleeved on the outside of the spiral twisted wire core group at equal intervals.

7. The axially tensile-resistant water-blocking cable according to claim 1, characterized in that: The spiral armored protective layer is made of 0.25mm thick galvanized steel strip, wrapped at a spiral angle of 45°±3°, with a wrapping gap less than 0.25mm. The outside of the spiral armored protective layer is covered with a 0.35mm thick polyethylene anti-corrosion layer.

8. The axially tensile-resistant water-blocking cable according to claim 1, characterized in that: The first foaming agent component is: 90% isocyanate prepolymer and 10% ethylene glycol butyl ether; The second foaming agent component is: 45% polyether polyol powder, 20% sodium bicarbonate, 5% triethylenediamine and 30% water-absorbing resin, wherein the particle size of the polyether polyol powder is 50-80 μm, and the surface of the triethylenediamine powder is coated with a 0.1 μm zinc stearate hydrophobic layer.

9. The axially tensile-resistant water-blocking cable according to claim 1, characterized in that: The first foaming agent component is: hydrogen-containing silicone oil; The second foaming agent component is: 95% vinyl silicone oil and 5% fumed silica, wherein 2000ppm of platinum catalyst is added to the vinyl silicone oil.

10. The axially tensile-resistant water-blocking cable according to claim 1, characterized in that: The first foaming agent component is: isocyanate prepolymer; the second foaming agent component is: 85% amino polyether and 15% dichloromethane.

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