A flame-retardant B1 class mineral insulated cable with aluminum sheath

Abstract

The utility model belongs to cable technical field especially a kind of flame-retardant B1 level aluminium sheath mineral insulated cable, present and propose the following scheme, including conductor layer, the outside of conductor layer is surrounded and is wrapped with conductor shielding layer, the outside of conductor shielding layer is wrapped with damp-proof insulation layer;By setting damp-proof insulation layer and aluminium impact-resistant insulation layer, it can prevent external object from causing damage to conductor layer;Damp-proof insulation layer adopts super-clean 35KV and below crosslinking polyethylene insulation material extrusion and is wrapped on conductor shielding layer as insulation layer, the structure has less impurity, and it is not easy to induce electrical tree phenomenon to destroy insulation, avoid insulation aging deterioration;Aluminium impact-resistant insulation layer adopts 920 million ultrahigh molecular weight polyethylene fiber and aluminium material bonding and is wound outside copper tape shielding layer, the structure absorption energy capacity and the ability of resisting impact than carbon fiber, the bonding of polyethylene and aluminium material can be realized by surface modification or using hot melt adhesive, the polyethylene after modification and aluminium material can reach good bonding effect.

Description

Technical Field

[0001] This utility model relates to the field of cable technology, and in particular to a flame-retardant B1 grade aluminum sheathed mineral insulated cable. Background Technology

[0002] Flame-retardant B1-grade aluminum-sheathed mineral-insulated cable is a special cable that combines high flame retardancy, strong insulation, and mechanical protection. Its core uses mineral materials (such as magnesium oxide and aluminum oxide) as the insulating medium, and aluminum is used as the sheath. Its flame retardant performance meets the B1 grade standard in GB / T19666 "Flame-retardant and fire-resistant wires, cables or optical cables" (i.e., a high flame retardant level with "low smoke density, low toxicity, and low heat release rate"). It is suitable for places with extremely high safety and fire protection requirements.

[0003] As the conductive core of a cable, the material of the cable conductor directly affects the cable's current carrying capacity, weight, and cost. They are mainly divided into two categories: copper conductor, aluminum sheath, and mineral insulated cables. Copper conductors offer excellent conductivity (approximately 58 S / m), high current carrying capacity, and are resistant to oxidation and corrosion, exhibiting strong long-term operational stability. Aluminum conductor, aluminum sheath, and mineral insulated cables feature both conductors and sheaths made of aluminum. This "all-aluminum structure" significantly reduces costs (20%-30% lower than similar copper conductor products) and results in a lighter overall weight (density only 1 / 3 that of copper), making them particularly suitable for long-distance laying or scenarios with weight restrictions.

[0004] While existing aluminum sheaths are lightweight and less expensive than copper sheaths, they are less corrosion resistant. In humid, saline (such as coastal areas) or chemical environments, the oxide film on the aluminum surface is easily damaged. Long-term use may lead to sheath corrosion and perforation, which in turn causes the internal mineral insulation layer to absorb moisture (especially magnesium oxide insulation type), resulting in a decline in insulation performance.

[0005] Therefore, a flame-retardant B1-grade aluminum-sheathed mineral-insulated cable is needed. Utility Model Content

[0006] This utility model proposes a flame-retardant B1-grade aluminum-sheathed mineral-insulated cable, which solves the problem that although the aluminum sheath is lightweight and cheaper than the copper sheath, it has weak corrosion resistance. In humid, saline (such as coastal areas) or chemical environments, the oxide film on the aluminum surface is easily damaged, and long-term use may lead to sheath corrosion and perforation, which in turn causes the internal mineral insulation layer to absorb moisture (especially magnesium oxide insulation type), resulting in a decline in insulation performance.

[0007] To achieve the above objectives, this utility model provides the following technical solution: A flame-retardant B1-grade aluminum-sheathed mineral-insulated cable includes a conductor layer, a conductor shielding layer surrounding the outside of the conductor layer, and a moisture-proof insulation layer surrounding the outside of the conductor shielding layer. The moisture-proof insulation layer is surrounded by an insulating shielding layer, the insulating shielding layer is surrounded by a copper strip shielding layer, and the copper strip shielding layer is surrounded by an aluminum impact-resistant insulation layer.

[0008] Preferably, the aluminum impact-resistant insulation layer is externally filled with a halogen-free, low-smoke, and highly flame-retardant filler layer.

[0009] Preferably, the outer side of the halogen-free, low-smoke, high-flame-retardant filling layer is surrounded by a cable core impact-resistant layer, the outer side of the cable core impact-resistant layer is surrounded by an isolation layer, the outer side of the isolation layer is surrounded by an armor layer, the outer side of the armor layer is surrounded by a flame-retardant protective layer, and the outer side of the flame-retardant protective layer is surrounded by an outer sheath layer.

[0010] Preferably, a trapezoidal soft copper wire is provided on the outer side of the conductor layer, and the trapezoidal soft copper wire serves as an outer layer for rotating and tightly pressing the conductor layer.

[0011] Preferably, the conductor shielding layer is arranged in a fan-shaped ring, and the conductor shielding layer uses an ultra-slippery semi-conductive shielding material with acetylene black conductive filler. The moisture-proof insulation layer uses ultra-clean 35kV and below cross-linked polyethylene insulation material, and the insulation shielding layer uses an ultra-slippery semi-conductive shielding material with acetylene black conductive filler. The copper strip shielding layer is made of soft copper strips overlapping and wrapped, and the soft copper strips are distributed vertically at equal intervals. The aluminum impact-resistant insulation layer is made of 9.2 million ultra-high molecular weight polyethylene fiber and aluminum material bonded and layered.

[0012] Preferably, the halogen-free, low-smoke, and highly flame-retardant filler layer is made of lightweight halogen-free, low-smoke, and highly flame-retardant filler rope.

[0013] Preferably, the impact-resistant layer of the cable core is made of 9.2 million ultra-high molecular weight polyethylene fiber tape, the edge of the impact-resistant layer of the cable core has a hollow structure, the isolation layer is made of halogen-free polymer, and the outer side of the isolation layer has a convex structure.

[0014] Preferably, the armor layer is composed of double-layer galvanized steel strips wrapped in a crisscross pattern, the flame-retardant protective layer is composed of alkali-free fiberglass tape wrapped in an overlapping pattern, the outer sheath layer is made of halogen-free, low-smoke, flame-retardant polyolefin high flame-retardant sheath material, and the outer wall of the outer sheath layer has an arc-shaped structure design.

[0015] This utility model proposes a flame-retardant B1-grade aluminum-sheathed mineral-insulated cable. Compared with the prior art, the beneficial effects of this utility model are: By setting up a moisture-proof insulation layer and an aluminum impact-resistant insulation layer, damage to the conductor layer by foreign objects can be prevented. The moisture-proof insulation layer uses ultra-clean 35kV and below cross-linked polyethylene insulation material extruded and wrapped on the conductor shielding layer as an insulation layer. This structure has fewer impurities and is less likely to induce electric tree phenomenon that damages the insulation, thus avoiding insulation aging and deterioration. The aluminum impact-resistant insulation layer uses 9.2 million ultra-high molecular weight polyethylene fibers and aluminum materials bonded and wrapped around the copper strip shielding layer. This structure has a higher energy absorption capacity and impact resistance than carbon fiber. The bonding between polyethylene and aluminum materials can be achieved through surface modification or the use of hot melt adhesive. Modified polyethylene and aluminum materials can achieve good bonding effect. 2. By setting up an armor layer, a flame-retardant protective layer, and an outer sheath layer, the fire resistance of the cable is improved while its compressive strength is enhanced. The armor layer is composed of double-layer galvanized steel strips wrapped with gaps, and this structure can withstand high radial pressure. The flame-retardant protective layer is composed of alkali-free fiberglass tape wrapped in overlapping layers. This structure does not spread flames when exposed to fire and can also prevent the steel strip edges from embedding into the sheath and causing damage. The outer sheath layer uses halogen-free, low-smoke, flame-retardant polyolefin high flame-retardant sheath material, which not only has conventional properties such as halogen-free, low smoke, flame retardancy, and low toxicity, but also has good combustion crusting properties, low heat release during combustion, and short-term self-extinguishing properties, which greatly improves the overall flame-retardant performance of the cable. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a flame-retardant B1-grade aluminum-sheathed mineral-insulated cable proposed in this utility model. Figure 2 This is a schematic diagram of the overall structure of a flame-retardant B1-grade aluminum-sheathed mineral-insulated cable proposed in this utility model. Figure 3 This is a partial structural schematic diagram of a flame-retardant B1-grade aluminum-sheathed mineral-insulated cable proposed in this utility model. Figure 4 This is a partial structural schematic diagram of a flame-retardant B1-grade aluminum-sheathed mineral-insulated cable proposed in this utility model.

[0017] In the diagram: 1. Conductor layer; 2. Conductor shielding layer; 3. Moisture-proof insulation layer; 4. Insulation shielding layer; 5. Copper tape shielding layer; 6. Aluminum impact-resistant insulation layer; 7. Halogen-free, low-smoke, high flame-retardant filling layer; 8. Cable core impact-resistant layer; 9. Insulation layer; 10. Armoring layer; 11. Flame-retardant protective layer; 12. Outer sheath layer. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Please see Figure 1-4 This utility model provides a technical solution: a flame-retardant B1 grade aluminum sheath mineral insulated cable, including a conductor layer 1, a conductor shielding layer 2 wrapped around the outside of the conductor layer 1, and a moisture-proof insulation layer 3 wrapped around the outside of the conductor shielding layer 2. The moisture-proof insulation layer 3 is surrounded by an insulating shielding layer 4, the insulating shielding layer 4 is surrounded by a copper strip shielding layer 5, and the copper strip shielding layer 5 is surrounded by an aluminum impact-resistant insulation layer 6.

[0020] Furthermore, the aluminum impact-resistant insulation layer 6 is externally filled with a halogen-free, low-smoke, high-flame-retardant filler layer 7.

[0021] Furthermore, the outer side of the halogen-free, low-smoke, high flame-retardant filling layer 7 is wrapped with a cable core impact-resistant layer 8, the outer side of the cable core impact-resistant layer 8 is wrapped with an isolation layer 9, the outer side of the isolation layer 9 is wrapped with an armor layer 10, the outer side of the armor layer 10 is wrapped with a flame-retardant protective layer 11, and the outer side of the flame-retardant protective layer 11 is wrapped with an outer sheath layer 12.

[0022] Furthermore, a trapezoidal soft copper wire is provided on the outer side of conductor layer 1. The trapezoidal soft copper wire is used as an outer layer to rotate and twist to compress conductor layer 1. The compression coefficient of conductor layer 1 is higher than 0.98, the outer layer gap is small, the electric field is uniform, and the current carrying capacity and service life of the cable are improved.

[0023] Furthermore, the conductor shielding layer 2 is arranged in a fan-shaped ring structure. The conductor shielding layer 2 uses a super-smooth semi-conductive shielding material with acetylene black conductive filler. The moisture-proof insulation layer 3 uses ultra-clean 35kV and below cross-linked polyethylene insulation material. The insulation shielding layer 4 uses a super-smooth semi-conductive shielding material with acetylene black conductive filler. The copper strip shielding layer 5 is made of overlapping soft copper strips, which are distributed vertically at equal intervals. The aluminum impact-resistant insulation layer 6 is made of 9.2 million kcal / m³ ultra-high molecular weight polyethylene fiber bonded and layered with aluminum. The conductor shielding layer 2 uses a super-smooth semi-conductive shielding material with acetylene black conductive filler extruded and wrapped on the conductor layer 1 as the conductor shielding layer. This structure has a high surface smoothness and strong uniform electric field capability, effectively enabling shielding operations. The moisture-proof insulation layer 3 uses ultra-clean 35kV and below cross-linked polyethylene insulation material extruded... The insulating layer is wrapped around the conductor shielding layer 2. This structure has few impurities, making it less prone to inducing electric tree phenomena that could damage the insulation and preventing insulation aging and deterioration. The insulating shielding layer 4 is made of a super-smooth semi-conductive shielding material with acetylene black conductive filler, extruded and wrapped around the moisture-proof insulating layer 3. This structure has a high surface smoothness and strong uniform electric field capability. The copper strip shielding layer 5 is made of soft copper strips overlapped and wrapped around the insulating shielding layer 4. This structure also serves to create a uniform electric field. The aluminum impact-resistant insulating layer 6 is made of 9.2 million ultra-high molecular weight polyethylene fiber and aluminum material bonded and overlapped around the copper strip shielding layer 5. This structure has a higher energy absorption capacity and impact resistance than carbon fiber. The bonding between polyethylene and aluminum material can be achieved through surface modification or the use of hot melt adhesive. Modified polyethylene and aluminum material can achieve good bonding effect.

[0024] Furthermore, the halogen-free, low-smoke, high-flame-retardant filler layer 7 adopts a lightweight halogen-free, low-smoke, high-flame-retardant filler rope; the use of lightweight halogen-free, low-smoke, high-flame-retardant filler rope in the halogen-free, low-smoke, high-flame-retardant filler layer 7 can ensure the stability of the cable core structure at higher temperatures and reduce the probability of ignition between insulated cores.

[0025] Furthermore, the impact-resistant layer 8 of the cable core is made of 9.2 million ultra-high molecular weight polyethylene fiber tape, and the edge of the impact-resistant layer 8 has a hollow structure. The isolation layer 9 is made of halogen-free polymer, and the outer side of the isolation layer 9 has a convex structure. The impact-resistant layer 8 of the cable core is made of 9.2 million ultra-high molecular weight polyethylene fiber tape wrapped around the copper tape shielding layer 5. This structure has a higher energy absorption capacity and impact resistance than carbon fiber, which can prevent external impacts and sharp objects from piercing the cable core. The hollow structure design at the edge can further resist and buffer external impact forces. The isolation layer 9 is made of halogen-free polymer as raw material, with the addition of halogen-free flame retardants, antioxidants, lubricants and other additives, and is made by mixing, plasticizing and granulation. The oxygen index is not less than 40, and it has excellent flame retardant performance, halogen-free performance and low smoke performance.

[0026] Furthermore, the armor layer 10 is constructed by interlacing double-layer galvanized steel strips, the flame-retardant protective layer 11 is constructed by overlapping alkali-free fiberglass tapes, and the outer sheath layer 12 is constructed by using halogen-free, low-smoke, flame-retardant polyolefin high flame-retardant sheath material. The outer wall of the outer sheath layer 12 has an arc-shaped structure design. The armor layer 10 is constructed by interlacing double-layer galvanized steel strips, which can withstand high radial pressure. The flame-retardant protective layer 11 is constructed by overlapping alkali-free fiberglass tapes, which does not propagate flame when exposed to fire. The outer sheath layer 12 is constructed by using halogen-free, low-smoke, flame-retardant polyolefin high flame-retardant sheath material, which not only has conventional properties such as halogen-free, low-smoke, flame-retardant, and low-toxicity, but also has good combustion crusting properties, low heat release during combustion, and short-term self-extinguishing properties. The arc-shaped structure design of the outer sheath layer 12 can increase the friction coefficient and facilitate handling operations.

[0027] Working principle: First, this flame-retardant B1 grade aluminum sheath mineral insulated cable is composed of multiple layers. The conductor layer 1 has a compression coefficient higher than 0.98, small gaps between outer layers, and uniform electric field, which improves the current carrying capacity and service life of the cable. A conductor shielding layer 2, a moisture-proof insulation layer 3, and an aluminum impact-resistant insulation layer 6 are set on the outside of the conductor layer 1 to prevent foreign objects from damaging the conductor layer. The moisture-proof insulation layer 3 is made of ultra-clean 35kV and below cross-linked polyethylene insulation material extruded and wrapped on the conductor shielding layer 2 as an insulation layer. This structure has fewer impurities and is less likely to induce electric tree phenomenon to damage the insulation, thus avoiding insulation aging and deterioration. The aluminum impact-resistant insulation layer 6 is made of 9.2 million ultra-high molecular weight polyethylene fiber and aluminum material bonded and wrapped around the copper strip shielding layer 5. This structure has a higher energy absorption capacity and impact resistance than carbon fiber. The bonding between polyethylene and aluminum material can be achieved through surface modification or the use of hot melt adhesive. The modified polyethylene and aluminum material can achieve a good bonding effect. Secondly, the impact-resistant layer 8 of the cable core is made of 9.2 million ultra-high molecular weight polyethylene fiber tape wrapped around the copper tape shielding layer 5. This structure has a higher energy absorption capacity and impact resistance than carbon fiber, and can prevent external impacts and sharp objects from damaging the cable core. The isolation layer 9 is made of halogen-free polymer as raw material, with the addition of halogen-free flame retardants, antioxidants, lubricants and other additives, and is made by mixing, plasticizing and granulation. The oxygen index is not less than 40, and it has excellent flame retardant performance, halogen-free performance and low smoke performance.

[0028] Finally, the armor layer 10 is constructed by wrapping double-layer galvanized steel strips with gaps, which can withstand high radial pressure; the flame-retardant protective layer 11 is constructed by overlapping alkali-free fiberglass tapes, which does not spread flame when exposed to fire; the outer sheath layer 12 is made of halogen-free, low-smoke, flame-retardant polyolefin high flame-retardant sheath material, which not only has conventional properties such as halogen-free, low-smoke, flame-retardant and low-toxicity, but also has good combustion crusting properties, low heat release during combustion and short-term self-extinguishing properties.

[0029] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flame-retardant B1-grade aluminum-sheathed mineral-insulated cable, comprising a conductor layer (1), characterized in that: The conductor layer (1) is surrounded by a conductor shielding layer (2), and the conductor shielding layer (2) is surrounded by a moisture-proof insulating layer (3). The moisture-proof insulation layer (3) is surrounded by an insulating shielding layer (4), the insulating shielding layer (4) is surrounded by a copper strip shielding layer (5), and the copper strip shielding layer (5) is surrounded by an aluminum impact-resistant insulation layer (6).

2. The flame-retardant B1-grade aluminum-sheathed mineral-insulated cable according to claim 1, characterized in that: The aluminum impact-resistant insulation layer (6) is filled with a halogen-free, low-smoke, high flame-retardant filler layer (7).

3. The flame-retardant B1-grade aluminum-sheathed mineral-insulated cable according to claim 2, characterized in that: The outer side of the halogen-free, low-smoke, high flame-retardant filling layer (7) is surrounded by a core impact-resistant layer (8), the outer side of the core impact-resistant layer (8) is surrounded by an isolation layer (9), the outer side of the isolation layer (9) is surrounded by an armor layer (10), the outer side of the armor layer (10) is surrounded by a flame-retardant protective layer (11), and the outer side of the flame-retardant protective layer (11) is surrounded by an outer sheath layer (12).

4. The flame-retardant B1-grade aluminum-sheathed mineral-insulated cable according to claim 1, characterized in that: The outer side of the conductor layer (1) is provided with a trapezoidal soft copper wire, which serves as an outer layer for rotating and tightly pressing the conductor layer (1).

5. A flame-retardant B1-grade aluminum-sheathed mineral-insulated cable according to claim 1, characterized in that: The conductor shielding layer (2) is arranged in a fan-shaped ring. The conductor shielding layer (2) is made of super-slippery semi-conductive shielding material with acetylene carbon black conductive filler. The moisture-proof insulation layer (3) is made of ultra-clean 35kV and below cross-linked polyethylene insulation material. The insulation shielding layer (4) is made of super-slippery semi-conductive shielding material with acetylene carbon black conductive filler. The copper strip shielding layer (5) is made of soft copper strips overlapping and wrapped. The soft copper strips are arranged in a vertical structure and are evenly distributed. The aluminum impact-resistant insulation layer (6) is made of 9.2 million ultra-high molecular weight polyethylene fiber and aluminum material bonded and wrapped.

6. A flame-retardant B1-grade aluminum-sheathed mineral-insulated cable according to claim 2, characterized in that: The halogen-free, low-smoke, high-flame-retardant filler layer (7) is made of lightweight halogen-free, low-smoke, high-flame-retardant filler rope.

7. A flame-retardant B1-grade aluminum-sheathed mineral-insulated cable according to claim 3, characterized in that: The impact-resistant layer (8) of the cable core is made of 9.2 million ultra-high molecular weight polyethylene fiber tape. The edge of the impact-resistant layer (8) of the cable core has a hollow structure. The isolation layer (9) is made of halogen-free polymer. The outer side of the isolation layer (9) has a convex structure.

8. A flame-retardant B1-grade aluminum-sheathed mineral-insulated cable according to claim 3, characterized in that: The armor layer (10) is made of double-layer galvanized steel strips wrapped in a gap, the flame-retardant protective layer (11) is made of alkali-free fiberglass tape wrapped in an overlapping manner, the outer sheath layer (12) is made of halogen-free low-smoke flame-retardant polyolefin high flame-retardant sheath material, and the outer wall of the outer sheath layer (12) is designed with an arc-shaped structure.

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