Axial anti-pulling water-blocking cable

Abstract

The invention provides an axial anti-pulling water-blocking cable, and relates to the technical field of water-blocking cables, a cable core is spirally twisted on a central anti-pulling bearing unit, the central anti-pulling bearing unit is used for bearing main pulling force, and due to the winding mode of the cable core, when the cable core is subjected to pulling force, the cable core can be prevented from being damaged. The cable core can extrude the central tensile bearing unit towards the center so as to obtain a certain extension buffer space, so that the conductor is prevented from being broken, and the liquid foaming agent capsule in the central tensile bearing unit is extruded and broken by utilizing an extrusion force exceeding a limited value; therefore, the first foaming agent in the cable penetrates through the woven central tensile bearing unit to be combined with the second foaming agent in the twisting gap of the cable core, a large amount of foam colloid is generated, a high-stress area, where water leakage possibly occurs, of the cable is pressurized and subjected to leaking stoppage, and active response to water blocking according to local stress sudden change is achieved. Compared with a traditional passive water blocking technology, the response speed is higher, 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 water-blocking cable. Background Art

[0002] A 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 interior, thereby ensuring the stability of power or signal transmission. Its core function is to prevent the intrusion of water through physical or chemical means, and it is suitable for use in humid and high-humidity environments such as cables for offshore wind power and mining drag cables.

[0003] Traditional water-blocking cables adopt passive water-blocking technologies, such as the water-blocking method using water-blocking powder and water-blocking tape to absorb and expand. It takes effect only after a part of the water has penetrated, which has serious hysteresis and is difficult to actively block water. At the same time, for existing cables used for purposes such as offshore wind power cables and mining drag cables, due to the protection of steel tape armor, the reasons for their immersion failure are mostly not caused by sharp object cuts, but by high tensile force or local extrusion stress resulting in the rupture and failure of the waterproof layer. The traditional physical water-blocking layer is also prone to rupture when the cable is subjected to pulling or local extrusion, rendering its water-blocking ability ineffective and resulting in unstable water-blocking effects. Summary of the Invention

[0004] The purpose of the present invention is to provide an axially tensile water-blocking cable to solve the problems of serious hysteresis and unstable water-blocking effect in the traditional cable technology described in the above background.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is an axially tensile water-blocking cable, including: a central tensile load-bearing unit woven from high-strength metal wires; a hollow tubular structure is provided inside the central tensile load-bearing unit, a liquid foaming agent capsule is filled inside the central tensile load-bearing unit, and a first foaming agent is filled inside the liquid foaming agent capsule; a spiral stranded core group is wrapped outside the central tensile load-bearing unit, the spiral stranded core group includes cable cores, and there are two or more cable cores, which are wound around the outside of the central tensile load-bearing unit in a precise spiral stranding manner; a gradient composite water-blocking layer is wrapped outside the spiral stranded core group, a water-blocking filling layer is provided inside 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 spiral stranded core group; a spiral armor protection layer is wrapped outside the gradient composite water-blocking layer, and the spiral armor protection layer is formed by spiral winding of steel strips.

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

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

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

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

[0010] In one example, the gradient composite water-blocking layer includes a stress-enhancing layer. The stress-enhancing layer uses a rubber elastic restraint ring. The stress-enhancing layer is sleeved outside the spiral stranded core group at equal intervals, used to limit the foam diffusion and increase the foam pressure in this area.

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

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

[0013] In one example, the first blowing agent component is: hydrogen-containing silicone oil; the second blowing agent component is: 95% vinyl silicone oil and 5% fumed silica. 2000 ppm platinum catalyst is added to the vinyl silicone oil; its core advantages are: the temperature resistance range is -60°C to 200°C, the water absorption rate is < 0.1%, the long-term seawater immersion performance is stable, and the biocompatibility is good; limitations: the expansion ratio is 5 - 8 times, an additional physical blowing agent is required, the cost is high, about 500 yuan / kg, and a special mixing equipment is required.

[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 1.0 - 1.5 MPa, suitable for high-pressure scenarios with water depth ≥ 100m; limitations: high requirements for substrate surface treatment, relatively large brittleness after curing, elongation at break ≤ 150%.

[0015] Compared with the prior art, the beneficial effects of the present invention include: An axially tensile and water-blocking cable proposed by the present invention, by helically stranding the cable core on the central tensile load-bearing unit, using the central tensile load-bearing unit to bear the main pulling force, and due to its winding method, when the cable core is subjected to tensile force, the cable core can squeeze towards the center against the central tensile load-bearing unit to obtain a certain elongation buffer space, avoiding conductor breakage and at the same time using the extrusion force exceeding the limit value to break the liquid foaming agent capsule in the central tensile load-bearing unit, so that the first foaming agent therein penetrates through the woven central tensile load-bearing unit and combines with the second foaming agent in the stranding gap between the cable core, generating a large amount of foam colloid, pressurizing and plugging the high-stress areas where the cable may leak water, thereby realizing active response to water blocking based on local stress mutation. Compared with the 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 will be described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present invention. In the drawings, the same reference numerals are used to refer to the same components. Among them: Figure 1 Schematically shows a sectional structure diagram of an axially tensile and water-blocking cable according to an embodiment of the present invention.

[0017] Reference numerals in the figure: 1, central tensile load-bearing unit; 2, liquid foaming agent capsule; 3, helically stranded core group; 301, cable core; 3011, conductor core; 3012, insulating coating layer; 4, gradient composite water-blocking layer; 401, basic water-blocking layer; 402, water-blocking filling layer; 403, stress enhancement layer; 5, helical armor protection layer; 501, polyethylene anti-corrosion layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] It is easy to understand that according to the technical solution of the present invention, without changing the essence of the present invention, those of ordinary skill in the art can propose various replaceable structural forms and implementation methods. Therefore, the following detailed description and the accompanying drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the whole of the present invention or as a limitation or restriction on the technical solution of the present invention.

[0019] According to the embodiments of the present invention in combination with Figure 1Shown. An axially tensile and water-blocking cable includes a central tensile load-bearing unit 1, a liquid foaming agent capsule 2, a helically stranded core group 3, a gradient composite water-blocking layer 4, and a helical armor protection layer 5.

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

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

[0022] III. The central tensile load-bearing unit 1 is externally helically stranded and wrapped with a helically stranded core group 3. The helically stranded core group 3 is composed of two or more cable cores 301 wound around the outside of the central tensile load-bearing unit 1 in a precise helical stranding manner. The twist pitch is 8 - 10 times the diameter of the cable core 301. The cable core 301 is composed of a conductor core 3011 and an insulating coating 3012 wrapped outside the conductor core 3011. Optionally, the conductor core 3011 adopts a single-core conductor or a multi-strand stranded conductor structure. The conductor material is selected from tin-plated copper or aluminum with high electrical conductivity, and its conductivity is detected to be not less than 97% IACS. Optionally, the insulating coating 3012 adopts cross-linked polyethylene or ethylene-propylene rubber material. The thickness of the insulating layer is between 0.6 - 1.2 mm, with excellent temperature resistance. The operating temperature range is -40°C to 120°C, and the breakdown voltage standard is ≥30 kV / mm.

[0023] IV. A gradient composite water-blocking layer 4 is arranged outside the helically stranded core group 3. The gradient composite water-blocking layer 4 is tightly wrapped around the outside of the helically stranded core group 3. The thickness of the gradient composite water-blocking layer 4 is designed to be 1.8 - 2.2 mm. The gradient composite water-blocking layer 4 is composed of the following multi-layer structures: The basic water-blocking layer 401: Adopts a high-elastic butyl rubber elastomer, and the Shore hardness A value is controlled at 55 - 60, providing a basic physical water-blocking protection function. The water-blocking filling layer 402: Uniformly fills the second foaming agent in powder form in the gaps of the helically stranded 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 is ≥85% within 5 minutes after encountering water. The stress enhancement layer 403; The stress enhancement layer 403 adopts an EPDM rubber elastic restraint ring with a thickness of 1 mm, which is sleeved on the outside of the helically stranded core group 3 at equal intervals, can effectively limit the foam diffusion range, and can 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 wound with a spiral angle of 45° ± 3°. The overlapping rate of winding is strictly guaranteed to be ≥ 18%, and the winding gap is accurately controlled to be ≤ 0.25 mm. The outside of the spiral armored protective layer 5 is covered with a 0.35 mm thick polyethylene anti-corrosion layer 501, which has strong compressive performance. The compressive strength is 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 can increase the overall tensile strength of the cable by 20% - 25%.

[0025] Example 1: System A: Two-component polyurethane foam system.

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

[0027] The second blowing agent: 45% polyether polyol micropowder 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, and the surface of the triethylenediamine powder is coated with a 0.1 μm zinc stearate hydrophobic layer; 30% water-absorbing resin, the resin is SAP with a particle size of 100 - 200 μm and a water absorption ratio of 500 - 1000 times, and the surface is coated with a 0.1 μm zinc stearate hydrophobic layer.

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

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

[0030] Example 2: System B: Two-component silicone rubber foam system.

[0031] The first blowing agent: Hydrogen-containing silicone oil with a hydrogen content of 0.15% - 0.2% and a viscosity of 300 - 500 mPa•s.

[0032] The second blowing agent: 95% vinyl silicone oil with a vinyl content of 0.1% - 0.15%, and 2000 ppm platinum catalyst is added. 5% fumed silica is used as a thickening agent.

[0033] Core advantages: Temperature resistance range: -60°C to 200°C, water absorption rate < 0.1%, stable performance after long-term seawater immersion, good biocompatibility. Limitations: Expansion ratio is 5 - 8 times, requires additional physical foaming agent, high cost, about 500 yuan / kg, and requires special mixing equipment.

[0034] Table 2 is a summary table of key performance test data:

[0035] Example 3: System C: Two-component polyurea foaming system.

[0036] The first foaming agent: Isocyanate prepolymer, NCO content 30% - 35%, viscosity ≤ 100 mPa•s.

[0037] The second foaming agent: 85% amino polyether, amine value 200 - 250 mgKOH / g. 15% methylene chloride, used as a physical foaming agent.

[0038] Core advantages: Extremely fast reaction, can be cured within 30 seconds, compressive strength 1.0 - 1.5 MPa, suitable for high-pressure scenarios with water depth ≥ 100 m. Limitations: High requirements for substrate surface treatment, relatively brittle after curing, elongation at break ≤ 150%.

[0039] Table 3 is a summary table of key performance test data:

[0040] Working principle: When an axially tensile and water-blocking cable in the present invention encounters excessive tensile force, the cable core 301 helically stranded and wound around the outer side of the central tensile load-bearing unit 1 will slide, squeezing the central tensile load-bearing unit 1, so that the cable core 301 can be slightly stretched and yield, enabling the central tensile load-bearing unit 1 to bear the main tensile force, thereby avoiding the fracture of the conductor core 3011.

[0041] When the pulling force is too large, the basic water-blocking layer 401 is likely to rupture. At the same time, the extrusion pressure of the cable core 301 will crush the liquid foaming agent capsule 2 inside the central tensile load-bearing unit 1, causing the first foaming agent stored in the liquid foaming agent capsule 2 to leak. Since the central tensile load-bearing unit 1 is woven from high-strength metal wires and has poor water-blocking performance, the first foaming agent can pass through the central tensile load-bearing unit 1 and combine with the second foaming agent to produce a large amount of colloidal foam, blocking the 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 the radial leakage of water but also prevent the axial diffusion of water. At the same time, the setting of the stress enhancement layer 403 can, to a certain extent, block the axial diffusion path of the foam, causing the foam pressure in the local area to rise suddenly, and resisting the external water pressure through the internal high pressure, further preventing the external water from leaking and greatly increasing the waterproof depth of the cable.

[0042] The technical scope of the present invention is not limited to the content described above. 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 and water-blocking cable, characterized in that, Comprising: A central tensile load-bearing unit, which is woven from metal wires; a hollow tubular structure is provided inside the central tensile load-bearing unit, a liquid foaming agent capsule is filled inside the central tensile load-bearing unit, and a first foaming agent is filled inside the liquid foaming agent capsule; a spiral stranded wire core group is wrapped outside the central tensile load-bearing unit, the spiral stranded wire core group includes cable cores, and the number of cable cores is two or more, and the cable cores are wound around the outside of the central tensile load-bearing unit in a spiral stranded manner; a gradient composite water-blocking layer is wrapped outside the spiral stranded wire core group, a water-blocking filling layer is provided inside 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 spiral stranded wire core group; a spiral armor protection layer is wrapped outside the gradient composite water-blocking layer, and the spiral armor protection layer is formed by spiral winding of a steel strip.

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

3. The axial tensile and water-blocking cable according to claim 1, wherein, The lay length of the spiral stranded wire core group is 8-10 times the diameter of the cable core.

4. The axial tensile and water-blocking cable according to claim 1, characterized in that, The cable core includes a conductor wire core and an insulating coating layer, and the insulating coating layer is wrapped outside the conductor wire core.

5. The axial tensile and water-blocking cable according to claim 1, characterized in that, The gradient composite water-blocking layer includes the outside of a basic water-blocking layer.

6. The axial tensile and water-blocking cable according to claim 5, characterized in that, The gradient composite water-blocking layer includes a stress enhancement layer, the stress enhancement layer uses a rubber elastic restraint ring, and the stress enhancement layer is sleeved outside the spiral stranded wire core group at equal intervals.

7. The axial tensile and water-blocking cable according to claim 1, wherein The spiral armor protection layer is made of a galvanized steel strip with a thickness of 0.25 mm, and is wound with a spiral angle of 45°±3°, and the winding gap is less than 0.25 mm, and a polyethylene anticorrosion layer with a thickness of 0.35 mm is covered outside the spiral armor protection layer.

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

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

10. The axial tensile and water-blocking cable according to claim 1, wherein The component of the first foaming agent is: isocyanate prepolymer; the component of the second foaming agent is: 85% amino polyether and 15% dichloromethane.

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