Self-extinguishing flexible mineral insulated cable

Abstract

The utility model provides a self-extinguishing flexible mineral insulated cable, which comprises a plurality of wire cores, a wrapping layer wrapping the periphery of each wire core, a flame-retardant filler filled between the wrapping layer and the wire cores, and a sheath layer group wrapping the periphery of the wrapping layer, wherein the material of the flame-retardant filler is any one or more of sodium bicarbonate, ammonium dihydrogen phosphate and diammonium hydrogen phosphate, and by selecting the material of the flame-retardant filler, when the cable works under an extremely high temperature condition, on one hand, the sheath layer group has relatively high flame-retardant performance, and on the other hand, the sheath layer group has relatively high flame-retardant performance; on the other hand, even if the sheath layer group is carbonized or melted at a high temperature, the flame-retardant filler can quickly extinguish flames, quickly inhibit fire spreading and protect the cable core, the whole cable does not need to be replaced, the spreading speed of a fire disaster is reduced, and the service life of the cable is prolonged. And the device has the advantages of being simple in structure, low in production cost and convenient to popularize and implement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of flame-retardant cable production, and particularly relates to a self-extinguishing flexible mineral insulated cable. BACKGROUND

[0002] In the prior art, a traditional flexible mineral insulated cable, referred to as MI cable, is a cable wrapped with a copper sheath around a copper conductor core, and with magnesium oxide powder as an inorganic insulation material to isolate the conductor and the sheath. The outermost layer can be selected as needed. Such a cable has excellent fire resistance, high temperature resistance, corrosion resistance, explosion-proof and other characteristics, and is widely used in high-rise buildings, petrochemical industry, airports, tunnels, ships and other occasions.

[0003] In the prior art, the traditional flexible mineral insulated cable is favored due to its fire resistance. The cable shows excellent fire resistance under ordinary fire conditions, and can effectively prevent damage to the internal circuit by fire. However, when faced with extreme high temperature environment or long time fire test, the limitations of the traditional flexible mineral insulated cable become more and more obvious. Under extreme conditions, the copper sheath of the traditional cable may melt due to high temperature and thus lose structural strength, thereby directly affecting the overall fire stability of the cable. These high temperature conditions not only can damage the integrity of the copper sheath, but also can cause the magnesium oxide as the inner insulation material to react chemically, thereby affecting the insulation effect of the cable. Although the traditional mineral insulated cable can maintain short-term power supply in a fire, after the fire is over, the sheath and insulation layer of the cable may be damaged and cannot be used, and must be replaced. This can cause secondary loss to some critical facilities that need to maintain power supply for a long time, such as fire fighting systems and emergency lighting, and cannot quickly suppress the spread of fire, increasing the maintenance cost and difficulty after the fire. Therefore, there is an urgent need for improvement. CONTENT OF THE UTILITY MODEL

[0004] The present application is proposed to solve the technical problem in the prior art that the structural strength of the traditional flexible mineral insulated cable will be significantly reduced under extreme high temperature conditions, the copper sheath layer inside the cable will melt due to high temperature and thus lose structural strength, the mineral filler magnesium oxide inside the cable will react chemically under extreme high temperature conditions, thereby directly affecting the overall fire stability of the cable, the flame retardant performance is limited, and when the fire is large, the spread of the fire cannot be stopped. During the fire, the fire will spread to the inside of the cable, and after the fire is over, the whole cable needs to be replaced, and the maintenance cost and difficulty after the disaster are high.

[0005] The application adopts the following scheme, a self-extinguishing flexible mineral insulated cable, comprising a root core, a wrapping layer wrapped on the outer periphery of each of the core, a fire-retardant filler filled between the wrapping layer and the core, and a sheath layer group wrapped on the outer periphery of the wrapping layer, the material of the fire-retardant filler is any one or any multiple of sodium bicarbonate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate.

[0006] In some possible embodiments, the core comprises a conductor and an insulating layer wrapped on the outer periphery of the conductor, the material of the insulating layer is halogen-free cross-linked polyethylene.

[0007] In some possible embodiments, the conductor is composed of N strands of conductor single wires, the material of the conductor single wire is the fifth type of copper conductor, and the value range of N is a positive integer of 2-38.

[0008] In some possible embodiments, the material of the wrapping layer is any one of non-woven fabric, PVC tape, glass silk tape, mica tape, calcined mica tape and PTFE raw material tape.

[0009] In some possible embodiments, the sheath layer group comprises a first sheath layer wrapped on the outer periphery of the wrapping layer, a second sheath layer wrapped on the outer periphery of the first sheath layer, and a third sheath layer wrapped on the outer periphery of the second sheath layer, and the cross-sectional shape of the second sheath layer is gear-shaped.

[0010] In some possible embodiments, the second sheath layer comprises a sheath body wrapped on the outer periphery of the first sheath layer, and gear protrusions are spaced and arranged on the outer periphery of the sheath body with the center of the sheath body as the center, and the material of the second sheath layer is silicone rubber.

[0011] In some possible embodiments, the thickness of the sheath body is less than or equal to the thickness of the gear protrusions.

[0012] In some possible embodiments, the material of the first sheath layer is corrugated copper.

[0013] In some possible embodiments, the material of the third sheath layer is any one of cross-linked polyethylene, chlorosulfonated polyethylene, neoprene, styrene butadiene rubber, methyl vinyl silicone rubber and linear low density polyethylene.

[0014] Compared with the prior art, the application has the following beneficial effects:

[0015] The application provides a self-extinguishing flexible mineral insulated cable, which comprises a plurality of cores, a wrapping layer wrapped on the outer periphery of each core, a fire-retardant filler filled between the wrapping layer and the core, and a sheath layer group wrapped on the outer periphery of the wrapping layer, wherein the material of the fire-retardant filler is any one or more of sodium bicarbonate, ammonium dihydrogen phosphate and di-ammonium hydrogen phosphate. By selecting the material of the fire-retardant filler, when the cable works under extremely high temperature, on the one hand, the sheath layer group has high fire-retardant performance, and the cable can also ensure high mechanical strength under extremely high temperature; on the other hand, even if the sheath layer group is carbonized or melted at high temperature, the fire-retardant filler can quickly extinguish the flame and quickly suppress the spread of the fire, thereby protecting the core of the cable, reducing the spread speed of the fire, and reducing the maintenance cost and difficulty after the disaster, and the application has the advantages of simple structure, low production cost and easy popularization and implementation. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a cross-sectional structure schematic diagram of the self-extinguishing flexible mineral insulated cable. DETAILED DESCRIPTION

[0017] In combination with the content shown in the drawings, the technical scheme provided by the application is further described as follows. Figure 1 A self-extinguishing flexible mineral insulated cable comprises a core 1, a wrapping layer 2 wrapped on the outer periphery of each core 1, a fire-retardant filler 3 filled between the wrapping layer 2 and the core 1, and a sheath layer group 4 wrapped on the outer periphery of the wrapping layer 2, wherein the material of the fire-retardant filler 3 is any one or more of sodium bicarbonate, ammonium dihydrogen phosphate and di-ammonium hydrogen phosphate.

[0018] In the actual implementation process, by using any one or more of sodium bicarbonate, ammonium dihydrogen phosphate or di-ammonium hydrogen phosphate as the material of the fire-retardant filler 3, the cable can be effectively prevented from burning in a high-temperature environment, and a large amount of carbon dioxide and water vapor can be released by the decomposition of the filler when the cable core 1 is on fire in the early stage, so as to rapidly reduce the oxygen concentration around the cable, thereby effectively suppressing the spread of the fire and achieving the effect of self-extinguishing, improving the safety performance and fireproof grade of the cable, ensuring that the fire source can be put out or controlled as soon as possible in the early stage of the fire, reducing the damage that the fire may cause to the cable and the surrounding environment, and reducing the scope of the fire to the minimum.

[0019] In the implementation process of the embodiment, the core 1 comprises a conductor 10 and an insulating layer 11 wrapped on the outer periphery of the conductor, and the material of the insulating layer 11 is halogen-free cross-linked polyethylene.

[0020] In actual implementation, by adopting the design of the conductor 10 being externally coated with the insulating layer 11 made of halogen-free cross-linked polyethylene material, the flame-retardant performance and electrical performance of the core 1 are effectively improved, the release of harmful halogen is avoided, the safety and stability in high-temperature environment are ensured, and thus the overall performance and use safety of the cable are significantly improved.

[0021] In actual implementation, the conductor 10 is formed by twisting N conductor single wires, and the material of the conductor single wire is the fifth type of copper conductor, and N is a positive integer in the range of 2-38.

[0022] In actual implementation, for example, N is 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, or 38.

[0023] In actual implementation, by selecting the sixth type of copper conductor material as the material of the conductor single wire and combining with reasonable N value setting, the electrical performance of the conductor can be effectively improved, the current-carrying capacity of the conductor can be enhanced, and the energy loss of the conductor in the transmission process can be reduced, so as to improve the efficiency and stability of the overall circuit and meet the specific requirements of different application scenarios on the performance of the conductor.

[0024] In actual implementation, the material of the conductor 10 is the fifth type of copper conductor.

[0025] In actual implementation, by setting the wrapping layer, good electrical insulation and mechanical protection effects can be provided in different application environments, and the stability and reliability of the overall structure are enhanced. No matter whether it is a harsh environmental condition or a complex use scenario, the diversified material options of the wrapping layer 2 can provide effective performance support, thereby improving the safety and durability of the product.

[0026] In actual implementation, the sheath layer group 4 includes the first sheath layer 40 wrapped on the outer periphery of the wrapping layer 2, the second sheath layer 41 wrapped on the outer periphery of the first sheath layer 40, and the third sheath layer 42 wrapped on the outer periphery of the second sheath layer 41, and the cross-sectional shape of the second sheath layer 41 is a gear shape.

[0027] In actual implementation, the sheath layer group 4 is arranged by sequentially coating the first sheath layer 40, the second sheath layer 41 and the third sheath layer 42 on the outer periphery of the wrapping layer 2, thereby forming a multi-layer protection structure and effectively improving the overall protection performance of the cable. In particular, the cross-sectional shape of the second sheath layer 41 is designed as a gear shape, which not only increases the contact area and friction of the sheath and enhances the anti-sliding performance of the cable, but also can disperse external force to a certain extent and reduce stress concentration, thereby effectively improving the mechanical strength and service life of the cable.

[0028] In actual implementation, the sheath layer group 4 is arranged by sequentially coating the first sheath layer 40, the second sheath layer 41 and the third sheath layer 42 on the outer periphery of the wrapping layer 2, thereby forming a multi-layer protection structure and effectively improving the overall protection performance of the cable. In particular, the cross-sectional shape of the second sheath layer 41 is designed as a gear shape, which not only increases the contact area and friction of the sheath and enhances the anti-sliding performance of the cable, but also can disperse external force to a certain extent and reduce stress concentration, thereby effectively improving the mechanical strength and service life of the cable.

[0029] In actual implementation, by arranging the sheath body and the gear protrusion, the gear protrusion and the inner side of the third sheath layer can form a flame-retardant cavity, thereby improving the protection level of the first sheath layer, avoiding melting of the copper first sheath layer under extreme high temperature conditions, and improving the service life of the cable.

[0030] In actual implementation, by arranging the sheath body and the gear protrusion, the gear protrusion and the inner side of the third sheath layer can form a flame-retardant cavity, thereby improving the protection level of the first sheath layer, avoiding melting of the copper first sheath layer under extreme high temperature conditions, and improving the service life of the cable.

[0031] In actual implementation, by arranging the sheath body and the gear protrusion, the gear protrusion and the inner side of the third sheath layer can form a flame-retardant cavity, thereby improving the protection level of the first sheath layer, avoiding melting of the copper first sheath layer under extreme high temperature conditions, and improving the service life of the cable.

[0032] In actual implementation, by arranging the sheath body and the gear protrusion, the gear protrusion and the inner side of the third sheath layer can form a flame-retardant cavity, thereby improving the protection level of the first sheath layer, avoiding melting of the copper first sheath layer under extreme high temperature conditions, and improving the service life of the cable.

[0033] In actual implementation, by arranging the sheath body and the gear protrusion, the gear protrusion and the inner side of the third sheath layer can form a flame-retardant cavity, thereby improving the protection level of the first sheath layer, avoiding melting of the copper first sheath layer under extreme high temperature conditions, and improving the service life of the cable.

[0034] In actual implementation, by arranging the sheath body and the gear protrusion, the gear protrusion and the inner side of the third sheath layer can form a flame-retardant cavity, thereby improving the protection level of the first sheath layer, avoiding melting of the copper first sheath layer under extreme high temperature conditions, and improving the service life of the cable.

[0035] The above is only an embodiment of the present application, and is not used to limit the present application, and any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A self-extinguishing flexible mineral insulated electrical cable, characterized in that, The root core (1), the wrapping layer (2) wrapped on the outer periphery of each core (1), the flame-retardant filler (3) filled between the wrapping layer (2) and the core (1), and the sheath layer group (4) wrapped on the outer periphery of the wrapping layer (2) are included, and the material of the flame-retardant filler (3) is any one or more of sodium bicarbonate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate.

2. A self-extinguishing flexible mineral insulated electrical cable according to claim 1, characterized in that The core (1) includes a conductor (10) and an insulating layer (11) wrapped on the outer periphery of the conductor, and the material of the insulating layer (11) is halogen-free cross-linked polyethylene.

3. A self-extinguishing flexible mineral insulated electrical cable according to claim 2, c h a r a c t e r i s e d in that The conductor (10) is twisted by N strands of conductor single wires, and the material of the conductor single wire is a fifth type of copper conductor, and the value range of N is a positive integer of 2-38.

4. A self-extinguishing flexible mineral insulated electrical cable according to claim 1, characterized in that The material of the wrapping layer (2) is any one of non-woven fabric, PVC tape, glass tape, mica tape, calcined mica tape, and PTFE raw material tape.

5. A self-extinguishing flexible mineral insulated electrical cable according to claim 1, characterized in that The sheath layer group (4) includes a first sheath layer (40) wrapped on the outer periphery of the wrapping layer (2), a second sheath layer (41) wrapped on the outer periphery of the first sheath layer (40), and a third sheath layer (42) wrapped on the outer periphery of the second sheath layer (41), and the cross-sectional shape of the second sheath layer (41) is gear-shaped.

6. A self-extinguishing flexible mineral insulated electrical cable according to claim 5, c h a r a c t e r i s e d in that The second sheath layer (41) includes a sheath body (410) wrapped on the outer periphery of the first sheath layer (40), and gear protrusions (411) are spaced and arranged on the outer periphery of the sheath body (410) with the center of the sheath body (410) as the center, and the material of the second sheath layer (41) is silicone rubber.

7. A self-extinguishing flexible mineral insulated electrical cable according to claim 6, c h a r a c t e r i s e d in that The thickness of the sheath body (410) is less than or equal to the thickness of the gear protrusions (411).

8. A self-extinguishing flexible mineral insulated electrical cable according to claim 5, characterized in that The material of the first sheath layer (40) is corrugated copper.

9. A self-extinguishing flexible mineral insulated electrical cable according to claim 5, characterized in that The material of the third sheath layer (42) is any one of cross-linked polyethylene, chlorosulfonated polyethylene, neoprene, styrene-butadiene rubber, methyl vinyl silicone rubber, and linear low-density polyethylene.

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