A waterproof cable

Abstract

The utility model belongs to cable technical field especially relates to a waterproof cable, cable core is as the core component of electric power transmission, and the inside semiconductor layer concentrically covers the outside of cable core, the function of this layer is to fill the tiny gap between cable core and insulating layer, avoids partial discharge due to the gap, protects the insulating layer from being damaged, and the insulating layer concentrically covers the outside of inside semiconductor layer, and the outside semiconductor layer concentrically covers the outside of insulating layer, and its main function is even electric field distribution, the first water -resistant layer concentrically covers the outside of outside semiconductor layer, prevents moisture from entering, and the semiconductor polymer layer concentrically covers the outside of first water -resistant layer, this layer not only can play the electric field buffer effect, but also can enhance the bonding force between first water -resistant layer and second water -resistant layer, and the second water -resistant layer concentrically covers the outside of semiconductor polymer layer, and forms double waterproof guarantee with first water -resistant layer, and the outer sheath concentrically covers the outside of second water -resistant layer, provides protection for the whole cable.

Description

Technical Field

[0001] This utility model belongs to the field of cable technology, and in particular relates to a waterproof cable. Background Technology

[0002] A cable is a device for transmitting electrical energy or signals. Cables include power cables, control cables, compensating cables, shielded cables, high-temperature cables, computer cables, signal cables, coaxial cables, fire-resistant cables, marine cables, mining cables, and aluminum alloy cables, etc. They are made of one or more mutually insulated conductors and an outer insulating protective layer. They are wires that transmit electricity or information from one place to another. However, existing cables have poor waterproof performance. They are usually laid underground or erected in the air, and moisture can easily enter the inside of the cable, affecting its service life and safety. Utility Model Content

[0003] The purpose of this utility model is to provide a waterproof cable to address the aforementioned technical problems, thereby solving the issues raised in the background section.

[0004] In view of this, the present invention provides a waterproof cable, including a cable core; The inner semiconductor layer is concentrically wrapped around the outside of the cable core. An insulating layer is concentrically wrapped around the outer side of the inner semiconductor layer. The outer semiconductor layer is concentrically wrapped around the outside of the insulating layer. The first water-blocking layer is concentrically wrapped around the outer side of the outer semiconductor layer; A semiconductor polymer layer is concentrically wrapped around the outside of the first water-blocking layer. The second water-blocking layer is concentrically wrapped around the outside of the semiconductor polymer layer. The outer sheath is concentrically wrapped around the outside of the second water-blocking layer.

[0005] In the above technical solution, the longitudinal edges of the first water-blocking layer are overlapped and bonded together with adhesive to form a first connecting end extending along the cable core axis.

[0006] In the above technical solution, the longitudinal edges of the second water-blocking layer are overlapped and then soldered with lead-free solder to form a second connection end extending along the cable core axis.

[0007] In the above technical solution, the first connecting end and the second connecting end are further offset from each other in the circumferential direction of the cable core.

[0008] In the above technical solution, a conductive coating material is further filled between the insulating layer and the outer semiconductor layer.

[0009] In the above technical solution, furthermore, a number of hollow grooves are provided on the inner circumference of the insulating layer.

[0010] In the above technical solution, furthermore, the conductivity of the conductive coating material is not greater than the conductivity of the outer semiconductor layer.

[0011] In the above technical solution, further, the thickness of the conductive coating material after being coated on the outer peripheral surface of the insulating layer is not less than the thickness of the outer semiconductor layer.

[0012] The beneficial effects of this utility model are as follows: 1. The second water-blocking layer is concentrically wrapped around the outside of the semiconductor polymer layer and is also made of metal foil, forming a double waterproof protection with the first water-blocking layer.

[0013] 2. After the conductive coating material fills the gap between the insulating layer and the outer semiconductor layer, it forms a synergistic waterproofing with the first water-blocking layer and the second water-blocking layer. The outer water-blocking layer blocks the intrusion of external water, and the conductive coating material blocks the diffusion of the already infiltrated water to the core of the insulating layer, further reducing the probability of the occurrence of "external water tree".

[0014] 3. Several hollow grooves are provided on the inner circumference of the insulation layer, which can reduce the thickness of the insulation layer and reduce the size of the cable while ensuring insulation performance. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model; The markings in the diagram are as follows: 1-Cable core, 2-Inner semiconductor layer, 3-Insulation layer, 4-Outer semiconductor layer, 5-First water-blocking layer, 6-Semiconductor polymer layer, 7-Second water-blocking layer, 8-Outer sheath, 9-First connecting end, 10-Second connecting end, 11-Conductive coating material, 12-Hollow groove. Detailed Implementation

[0016] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0017] Example 1: This embodiment provides a waterproof cable, including: Cable core 1; Inner semiconductor layer 2, which concentrically covers the outside of cable core 1; Insulating layer 3 is concentrically wrapped around the outer side of inner semiconductor layer 2; The outer semiconductor layer 4 is concentrically wrapped around the outside of the insulating layer 3; The first water-blocking layer 5 is concentrically wrapped around the outside of the outer semiconductor layer 4. Semiconductor polymer layer 6, which is concentrically wrapped around the outside of the first water-blocking layer 5; The second water-blocking layer 7 is concentrically wrapped around the outside of the semiconductor polymer layer 6. Outer sheath 8 is concentrically wrapped around the outside of the second water-blocking layer 7.

[0018] As can be seen in this embodiment, the cable core 1, as the core component for power transmission, is made of a metal material with excellent conductivity. It can be a single solid metal wire, a multi-strand stranded metal wire, or a Milligan structure. Preferred metal materials include aluminum, aluminum alloys, copper, and copper alloys. The multi-strand stranded structure enhances the cable's flexibility, making it more adaptable to complex wiring environments. The inner semiconductor layer 2 concentrically covers the outside of the cable core 1 and is made of a polymer material with added conductive components (such as carbon black). The substrate can be cross-linked polyethylene (XLPE), polypropylene (PP), ethylene propylene diene monomer (EPDM), or ethylene propylene rubber (EPR). This layer fills the gap between the cable core 1 and the insulation layer 3. A tiny gap is formed to prevent partial discharge and protect the insulating layer 3 from damage. The insulating layer 3 concentrically covers the outer side of the inner semiconductor layer 2 and is made of a polymer material with excellent insulating properties, such as XLPE, PP, EPDM, or EPR. The outer semiconductor layer 4 concentrically covers the outer side of the insulating layer 3 and is made of a polymer with added conductive components, similar to the inner semiconductor layer. Its main function is to uniformly distribute the electric field. The first water-blocking layer 5 concentrically covers the outer side of the outer semiconductor layer 4 and is made of metal foil with a radial thickness of 0.1-0.5 mm to prevent moisture from entering. The semiconductor polymer layer 6 concentrically covers the outer side of the first water-blocking layer 5 and is made of XLPE, PP, or EPDM. It is made of polymers such as EPR with added conductive components and is coated by extrusion molding. This layer not only acts as an electric field buffer, but also enhances the bonding force between the first water-blocking layer 5 and the second water-blocking layer 7. The second water-blocking layer 7 is concentrically wrapped around the outside of the semiconductor polymer layer 6. It also uses metal foil with a radial thickness of 0.1-0.5mm, forming a double waterproof protection with the first water-blocking layer 5. The outer sheath 8 is concentrically wrapped around the outside of the second water-blocking layer 7, providing protection for the entire cable.

[0019] Example 2: This embodiment provides a waterproof cable, which, in addition to the technical solutions of the above embodiments, also has the following technical features.

[0020] The longitudinal edges of the first water-blocking layer 5 are overlapped and bonded together with adhesive to form the first connecting end 9 extending along the axial direction of the cable core 1.

[0021] As can be seen in this embodiment, the longitudinal edges of the first water-blocking layer 5 are overlapped and bonded together with adhesive to form the first connecting end 9 extending along the axial direction of the cable core 1. The adhesive is a high-temperature resistant hot melt adhesive to ensure stable bonding during cable processing and use, and to prevent moisture from entering from the joint.

[0022] Example 3: This embodiment provides a waterproof cable, which, in addition to the technical solutions of the above embodiments, also has the following technical features.

[0023] The longitudinal edges of the second water-blocking layer 7 are overlapped and then soldered with lead-free solder to form a second connecting end 10 extending along the axial direction of the cable core 1.

[0024] As can be seen in this embodiment, the longitudinal edges of the second water-blocking layer 7 are overlapped and then welded with lead-free solder to form the second connecting end 10 extending along the axial direction of the cable core 1. The lead-free solder can be a tin alloy containing elements such as silver, copper, antimony, bismuth, zinc, and nickel, which not only meets environmental protection requirements but also ensures high strength and high sealing performance of the joint.

[0025] Example 4: This embodiment provides a waterproof cable, which, in addition to the technical solutions of the above embodiments, also has the following technical features.

[0026] The first connecting end 9 and the second connecting end 10 are offset from each other in the circumferential direction of the cable core 1.

[0027] As can be seen from this embodiment, the first connecting end 9 and the second connecting end 10 are offset from each other by 90°-270° (preferably 160°-200°, most preferably 180°) in the circumferential direction of the cable core 1. Even if one of the joints has a sealing defect, the other joint can effectively block moisture, forming a double waterproof guarantee.

[0028] Example 5: This embodiment provides a waterproof cable, which, in addition to the technical solutions of the above embodiments, also has the following technical features.

[0029] A conductive coating material 11 is filled between the insulating layer 3 and the outer semiconductor layer 4.

[0030] As can be seen in this embodiment, a conductive coating material 11 is filled between the insulating layer 3 and the outer semiconductor layer 4. It needs to cover the entire circumference of the cable to fill the gap between the two layers. This material can be a viscous fluid or a paste, preferably conductive silicone. Filling with the conductive coating material 11 can prevent partial discharge. After the conductive coating material 11 fills the gap between the insulating layer 3 and the outer semiconductor layer 4, it forms a synergistic waterproofing with the first water-blocking layer 5 and the second water-blocking layer 7. The outer water-blocking layer blocks the intrusion of external water, and the conductive coating material 11 blocks the diffusion of the already infiltrated water to the core of the insulating layer 3, further reducing the probability of the occurrence of "external water tree".

[0031] Example 6: This embodiment provides a waterproof cable, which, in addition to the technical solutions of the above embodiments, also has the following technical features.

[0032] The inner circumference of the insulating layer 3 is provided with several hollow grooves 12.

[0033] As can be seen from this embodiment, a number of hollow grooves 12 are uniformly arranged on the inner circumference of the insulation layer 3. The number of hollow grooves can be selected according to actual needs, such as 3-12 (when a single core corresponds to an independent insulation layer) or 4-20 (when multiple cores share a common core insulation layer). Each hollow groove 12 is parallel to the axial direction of the cable core 1. The air (dielectric constant of about 1) in the hollow groove 12 and the insulating material (such as fluorinated ethylene propylene FEP with a dielectric constant of about 2.1) form a composite insulation structure, which can significantly reduce the overall dielectric constant. Under the premise of ensuring insulation performance, the thickness of the insulation layer can be reduced and the cable volume can be reduced.

[0034] Example 7: This embodiment provides a waterproof cable, which, in addition to the technical solutions of the above embodiments, also has the following technical features.

[0035] The conductivity of the conductive coating material 11 is not greater than the conductivity of the outer semiconductor layer 4.

[0036] As can be seen from this embodiment, the conductivity of the conductive coating material 11 is not greater than that of the outer semiconductor layer 4, forming a smooth conductivity gradient of "insulating layer (low conductivity) → conductive coating material (medium conductivity) → outer semiconductor layer (high conductivity)," which allows the electric field to "gradually transition" from the insulating layer 3 to the outer semiconductor layer 4, avoiding distortion and suppressing partial discharge from the source to protect the insulating layer 3.

[0037] Example 8: This embodiment provides a waterproof cable, which, in addition to the technical solutions of the above embodiments, also has the following technical features.

[0038] The thickness of the conductive coating material 11 after being coated on the outer peripheral surface of the insulating layer 3 is not less than the thickness of the outer semiconductor layer 4.

[0039] As can be seen from this embodiment, the thickness of the conductive coating material 11 after being coated on the outer peripheral surface of the insulating layer 3 is not less than the thickness of the outer semiconductor layer 4 and not less than 0.13 mm. The gap between the insulating layer 3 and the outer semiconductor layer 4 mainly comes from two aspects: the small unevenness (manufacturing error) on the surface of the insulating layer 3 and the bonding error when the outer semiconductor layer 4 is wrapped / extruded. If the thickness of the conductive coating material 11 is less than the thickness of the outer semiconductor layer 4, it may not be able to completely cover the contact interface between the outer semiconductor layer 4 and the insulating layer 3 due to insufficient thickness, resulting in local gaps not being filled and becoming discharge channels. The ease of peeling off the outer semiconductor layer 4 depends on the "flexible connection" effect of the conductive coating material 11. If the thickness of the conductive coating material 11 is too thin (e.g., less than 0.13 mm), the outer semiconductor layer 4 may directly contact the insulating layer 3 due to insufficient material (especially at the protrusions on the surface of the insulating layer 3), forming a "rigid bonding point," which will make peeling difficult or damage the insulating layer. The limit of "not less than 0.13 mm" is the minimum value based on actual process verification. This thickness can ensure that the conductive coating material 11 forms a continuous and complete "buffer layer" on the surface of the insulating layer, so that the outer semiconductor layer 4 is completely connected to the insulating layer 3 through the conductive coating material 11, ensuring the convenience and safety of peeling.

[0040] Connection method: The inner semiconductor layer 2 is concentrically wrapped around the outside of the cable core 1 by extrusion molding, and the fluidity of the molten polymer is used to tightly adhere to the surface of the cable core 1. The insulation layer 3 is directly wrapped around the outside of the inner semiconductor layer 2 by extrusion molding. The two form a "molecular-level bond" at high temperature. The insulation layer 3 and the outer semiconductor layer 4 are indirectly connected by a conductive coating material 11. The conductive coating material 11 is first uniformly coated on the surface of the insulation layer 3 to fill the tiny bumps on the surface of the insulation layer 3. The outer semiconductor layer 4 is wrapped around the outside of the coating material by extrusion or wrapping process, and the adhesion of the coating material is used to achieve a flexible bond. This connection method not only eliminates the gaps between layers, but also makes the outer semiconductor layer 4 more flexible. Semiconductor layer 4 can be easily peeled off. The first water-blocking layer 5 covers the outer semiconductor layer 4 by spiral winding or longitudinal wrapping. The overlapping parts of the foil edges are bonded with high-temperature resistant hot melt adhesive. The bonding process ensures that the metal foil and the outer semiconductor layer 4 are tightly bonded without wrinkles or bubbles, ensuring both water-blocking and sealing performance, and also assisting the outer semiconductor layer 4 in uniform electric field through the conductivity of the metal foil. Semiconductor polymer layer 6 is directly wrapped around the outside of the first water-blocking layer 5 by extrusion molding. The high temperature during extrusion (higher than the polymer melting temperature) makes the material tightly bonded to the surface of the metal foil. The molten polymer can fill the tiny unevenness on the surface of the metal foil, forming a "mechanical interlocking + The stable connection of "thermal bonding" is achieved, and the heat from extrusion helps to melt the hot melt adhesive at the joint of the first water-blocking layer 5, enhancing its sealing performance. The second water-blocking layer (also wrapped or covered by the semiconductor polymer layer 6, with the overlapping edges soldered with lead-free solder) achieves a high-strength seal for the metal foil, and the elasticity of the semiconductor polymer layer 6 can buffer the thermal stress during welding, preventing damage to the first water-blocking layer 5. The outer sheath 8 is extruded and integrally covers the outside of the second water-blocking layer 7, using a polymer material (such as PVC or FEP) that is compatible with the second water-blocking layer 7. During the extrusion process, the molten outer sheath material adheres tightly to the surface of the second water-blocking layer 7, and after cooling, it forms a "continuous and gapless" protective shell, which can not only fix the internal structure but also resist external mechanical damage and moisture ingress, providing final protection for the entire cable.

[0041] The embodiments of this application have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. This application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A waterproof cable, characterized in that, include: Cable core (1); An inner semiconductor layer (2) is concentrically wrapped around the outside of the cable core (1); An insulating layer (3) is concentrically wrapped around the outer side of the inner semiconductor layer (2); An outer semiconductor layer (4) is concentrically wrapped around the outside of the insulating layer (3); The first water-blocking layer (5) is concentrically wrapped around the outside of the outer semiconductor layer (4); A semiconductor polymer layer (6) is concentrically wrapped around the outside of the first water-blocking layer (5); The second water-blocking layer (7) is concentrically wrapped around the outside of the semiconductor polymer layer (6); Outer sheath (8), the outer sheath (8) is concentrically wrapped around the outside of the second water-blocking layer (7); The longitudinal edges of the first water-blocking layer (5) are overlapped and bonded together with adhesive to form a first connecting end (9) extending along the axial direction of the cable core (1). The longitudinal edges of the second water-blocking layer (7) are overlapped and then soldered with lead-free solder to form a second connection end (10) extending along the axial direction of the cable core (1). The first connecting end (9) and the second connecting end (10) are offset from each other in the circumferential direction of the cable core (1); The space between the insulating layer (3) and the outer semiconductor layer (4) is filled with a conductive coating material (11).

2. The waterproof cable according to claim 1, characterized in that, The insulating layer (3) has several hollow grooves (12) arranged on its inner circumference.

3. A waterproof cable according to claim 1, characterized in that, The conductivity of the conductive coating material (11) is not greater than that of the outer semiconductor layer (4).

4. A waterproof cable according to claim 1, characterized in that, The thickness of the conductive coating material (11) after being coated on the outer peripheral surface of the insulating layer (3) is not less than the thickness of the outer semiconductor layer (4).

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