1 kV fire-resistant cable

Abstract

This application relates to the field of fire-resistant cables, especially fire-resistant cables with a voltage of 1 kV. From the inside to the outside, it successively includes a conductive bundle, an armor layer, and an outer protective layer. The conductive bundle includes a number of conductor cores and a filling layer. Each conductor core is successively wrapped with a fire-resistant layer and an insulating layer from the inside to the outside. A tape layer with fire separation and fire prevention properties is provided between the conductive bundle and the armor layer. At the same time, an inner isolation layer for isolating the insulating layer and the fire-resistant layer is provided between the fire-resistant layer and the insulating layer. The inner isolation layer includes a layered inner substrate and a number of inner isolation columns with high heat resistance arranged at intervals. The inner isolation columns are uniformly fixed on the side of the inner substrate facing the insulating layer. The tape layer material of this application is selected as a fire-resistant material. At the same time, the inner isolation layer is provided to provide a deformation space for the insulating layer, reduce the extrusion damage of the fire-resistant layer caused by the stress deformation generated after the insulating layer is heated and melted and changed, improve the fire-resistant performance of the cable, and improve the defect of insufficient fire-resistant performance of the fire-resistant cable with non-woven fabric tape.

Description

Technical Field

[0001] This application relates to the field of fire-resistant cables, especially fire-resistant cables with a voltage of 1 kV. Background Art

[0002] A fire-resistant cable refers to a cable that can maintain safe operation for a certain period of time under flame combustion conditions and is widely used in many places related to fire safety and fire fighting and rescue.

[0003] In related technologies, a fire-resistant cable includes several conductor cores. Each conductor core is sequentially wrapped with a fire-resistant layer and an insulating layer from the inside to the outside. The several wrapped conductor cores are simultaneously wrapped with a tape layer. Outside the tape layer, there are also an armor layer and a sheath layer. Among them, the tape layer plays a role in protecting the insulating layer from being damaged by the armor skin during cable armoring or has different functions such as heat insulation, anti-corrosion, and anti-aging for the cable insulation due to different materials. The commonly used tape layer is a combustible non-woven fabric to reduce the extrusion damage of the tape layer to the fire-resistant layer during combustion.

[0004] Regarding the above-mentioned related technologies, the inventor believes that when the tape layer is selected as non-woven fabric, the combustibility of the non-woven fabric causes the tape layer to be unable to add additional fire-resistant performance to the fire-resistant cable. The fire-resistant performance of the fire-resistant cable with non-woven fabric tape only depends on the fire-resistant layer, and there is a defect of insufficient fire-resistant performance.

[0005] Content of the Invention Patent

[0006] In order to improve the defect of insufficient fire-resistant performance of the fire-resistant cable with non-woven fabric tape, this application provides a 1 kV fire-resistant cable.

[0007] The 1 kV fire-resistant cable provided by this application adopts the following technical solution: The 1 kV fire-resistant cable sequentially includes a conductive bundle, an armor layer, and an outer protective layer from the inside to the outside. The conductive bundle includes several conductor cores and a filling layer. Each conductor core is sequentially wrapped with a fire-resistant layer and an insulating layer from the inside to the outside. A tape layer with fire separation and fire prevention performance is provided between the conductive bundle and the armor layer. At the same time, an inner isolation layer for isolating the insulating layer and the fire-resistant layer is provided between the fire-resistant layer and the insulating layer. The inner isolation layer includes a layered inner substrate and several heat-resistant inner isolation columns arranged at intervals. The inner isolation columns are uniformly fixed on the side of the inner substrate facing the insulating layer.

[0008] By adopting the above technical solution, a gap is formed between the refractory layer and the insulating layer through the supporting effect of the inner isolation columns, providing a deformation space for the insulating layer; when the cable is surrounded by fire and burns, the insulating layer will be heated and melted, and the setting of the inner isolation layer can reduce the extrusion damage to the refractory layer caused by the stress deformation generated after the change of the insulating layer due to heating and melting; the tape layer is made of a material with the same refractory performance, so that the tape layer can also play a refractory role, enabling the tape layer of the refractory material to maintain the roundness of the conductive bundle after being burned by fire, and trying to maintain and stabilize the strength and structure of the conductive bundle, extending the time for the cable to operate safely under flame combustion, extending the refractory performance of the cable, and improving the defect of insufficient refractory performance of the non-woven tape-wrapped refractory cable.

[0009] Optionally, several of the inner isolation columns are spirally wound and arranged along the length direction of the conductive bundle.

[0010] By adopting the above technical solution, the inner isolation columns can be produced in the form of winding during the production process, reducing the production process difficulty; at the same time, the spiral winding arrangement can also enable the cable to maintain a certain bending ability, improving the practicability.

[0011] Optionally, an arc surface is formed on the side wall of the inner isolation column facing the insulating layer, and the arc surface abuts against the insulating layer.

[0012] By adopting the above technical solution, after the insulating layer is wound around the inner isolation layer, the setting of the arc surface can reduce the physical damage of the edges and corners of the inner isolation column to the insulating layer, improving the insulation quality of the cable.

[0013] Optionally, an outer isolation layer is provided between the tape layer and the armor layer, and the outer isolation layer includes a layered outer base material and several outer isolation columns arranged at intervals, and the outer isolation columns are uniformly fixed on the side of the outer base material facing the armor layer.

[0014] By adopting the above technical solution, a gap is formed between the tape layer and the armor layer by setting the outer isolation layer, providing a deformation space for the armor layer, reducing the extrusion damage of the stress deformation generated by the temperature change of the armor layer to the refractory tape layer, and also reducing the damage to the internal structure of the cable, improving the structural stability of the cable after being burned by fire, and improving the refractory performance.

[0015] Optionally, several of the outer isolation columns are spirally wound and arranged along the length direction of the conductive bundle.

[0016] By adopting the above technical solution, the outer isolation columns can also be produced in the form of winding during the production process, reducing the production process difficulty; at the same time, the spiral winding arrangement can also enable the cable to maintain a certain bending ability, improving the practicability.

[0017] Optionally, a plurality of air bags for assisting in fire extinguishing are provided between two adjacent outer isolation columns, and solid carbon dioxide for reducing the fire is filled in the air bags.

[0018] By adopting the above technical solution, the processing environment is in a low temperature during production and processing, and solid carbon dioxide is added to the air bags. When the production is completed, the solid carbon dioxide sublimes at room temperature, so that the air bags are filled with high-pressure carbon dioxide. When a fire burns into the inside of the armor layer during use, after the air bags are melted by the high temperature of the external fire or broken by the deformation of the armor layer, the high-pressure carbon dioxide inside will leak out. Under the action of pressure, the high-pressure carbon dioxide will quickly fill the air near the ignition point, dilute the oxygen concentration around the cable, effectively inhibit the penetration of the flame, have the ability to prevent or delay the occurrence or spread of the flame, ensure the integrity of the circuit, and further improve the fire resistance of the cable.

[0019] Optionally, a communication pipe for connecting them is provided between two adjacent air bags.

[0020] By adopting the above technical solution, the high-pressure carbon dioxide in the air bags at room temperature can be interconnected. On the one hand, it is beneficial to the bending of the cable and also helps to reduce the probability of pressing the air bags due to the bending of the cable. On the other hand, when the cable burns, not only the air bags at the burning point can play a certain fire extinguishing role after being damaged, but also the high-pressure carbon dioxide in the other interconnected air bags can quickly move to the damaged part under the action of pressure and jointly play a fire extinguishing role, further improving the fire resistance of the cable.

[0021] Optionally, a plurality of interconnected air bags can form an air bag strip, and a plurality of head-to-tail connected air bag strips are filled between every two adjacent outer isolation columns, and the air bag strips are not interconnected with each other.

[0022] By adopting the above technical solution, after the cable is damaged by fire, the high-pressure carbon dioxide in the air bag strip where the air bag at the damaged part is located can be used for emergency. The air bag strips far from the damaged part remain intact, reducing the probability of the entire cable being scrapped due to damage in one place, which is beneficial to improving the service life of the cable and reducing the maintenance cost.

[0023] Optionally, the fire-resistant layer is a synthetic fluorophlogopite tape.

[0024] By adopting the above technical solution, the synthetic fluorophlogopite tape replaces the hydrocarbon group with fluorine ions, does not contain crystal water, has a melting point of 1375°C, and has a large safety margin. It has the characteristics of natural mica tape, that is, in addition to the characteristics of small expansion coefficient, high dielectric strength, high resistivity, and uniform dielectric constant, it also has the characteristic of high heat resistance grade, fully meeting the fire resistance requirements of 950°C - 1000°C, which is beneficial to enhancing the fire resistance performance.

[0025] Optionally, the filling layer is an inorganic nano refractory rope.

[0026] By adopting the above technical solution, the filling layer has the characteristics of high temperature resistance, super softness, light specific gravity, high strength, etc., and does not contain harmful substances such as halogens, asbestos, and glass fiber. It has less smoke generation during combustion, meets the requirements of environmental protection and flame retardancy, and is also suitable for production.

[0027] To sum up, this application includes at least one of the following beneficial technical effects:

[0028] 1. The inner isolation layer provides a deformation space for the insulating layer, reducing the extrusion damage of the refractory layer caused by the stress deformation generated after the insulating layer melts under heat. The tape layer of the refractory material can also maintain the roundness of the conductive bundle after being burned by fire, and try to maintain and stabilize the strength and structure of the conductive bundle, extending the time for the cable to operate safely under flame combustion, and improving the defect of insufficient fire resistance performance of the non-woven tape-wrapped refractory cable;

[0029] 2. The outer isolation layer provides a deformation space for the armor layer, reducing the extrusion damage of the armor layer to the refractory tape layer caused by stress deformation due to temperature change, and also reducing the damage to the internal refractory layer of the cable, improving the structural stability of the cable after being burned by fire, and improving the fire resistance performance;

[0030] 3. When producing, solid carbon dioxide is added to the airbag, so that the cable can be protected by high-pressure carbon dioxide under normal temperature use; when the cable is surrounded by fire and burned, the airbag at the burning part will release high-pressure carbon dioxide after being damaged. At the same time, the high-pressure carbon dioxide in the remaining airbags in the same airbag strip will move to the damaged part for emergency rescue, so as to dilute the oxygen concentration around the cable, effectively inhibit the penetration of the flame, and have the ability to prevent or delay the occurrence or spread of the flame, ensuring the integrity of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a cross-sectional view of an embodiment of the present application.

[0032] Figure 2 is Figure 1 an enlarged view of part A in

[0033] Figure 3 is a schematic diagram of the internal structure of an embodiment of the present application.

[0034] Description of the reference numerals: 1, conductor core; 2, refractory layer; 3, inner isolation layer; 4, insulating layer; 5, conductive bundle; 6, tape layer; 7, outer isolation layer; 8, armor layer; 9, outer protective layer; 10, filling layer; 11, inner base material; 12, inner isolation column; 13, outer base material; 14, outer isolation column; 15, airbag strip; 16, airbag; 17, connecting pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following further elaborates on this application with reference to the attached drawings. Figures 1 - 3 This further details the present application.

[0036] An embodiment of this application discloses a 1 kV fire-resistant cable. Referring to Figure 1 , it includes three conductor cores 1. Each conductor core 1 is successively wrapped with a fire-resistant layer 2, an inner isolation layer 3, and an insulating layer 4 from the inside to the outside. The three conductor cores 1 together form a conductive bundle 5. The conductive bundle 5 is successively wrapped with a tape layer 6, an outer isolation layer 7, an armor layer 8, and an outer protective layer 9. A filling layer 10 is also filled between the conductive bundle 5 and the tape layer 6. The tape layer 6 simultaneously wraps the conductive bundle 5 and the filling layer 10, making the cross-section of the entire cable present a complete circle, increasing the structural stability and compressive strength.

[0037] Among them, the material of the fire-resistant layer 2 is selected as synthetic fluorophlogopite tape, and its performance is shown in the following table. Synthetic fluorophlogopite tape can replace the hydrocarbon group with fluoride ions, does not contain crystal water, has a large safety margin, and has the characteristics of natural mica tape, that is, in addition to small expansion coefficient, high dielectric strength, high resistivity, and uniform dielectric constant, it also has the characteristic of high heat resistance grade and better fire-resistant performance than natural mica tape. In addition, the thickness range of synthetic fluorophlogopite tape can also meet the requirements of daily ordinary equipment processes and is suitable for production.

[0038] Table 1 Performance of Synthetic Fluorophlogopite Tape

[0039]

[0040] The material of the insulating layer 4 is selected as a cross-linked polyethylene insulating layer, which is beneficial to improving the insulation performance of low-voltage cables and thus improving the electrical safety of the cables.

[0041] The material of the tape layer 6 is selected as a material with fire separation and fire prevention properties, such as mica tape or coated fiberglass tape, so that the tape layer 6 can not only wrap the conductive bundle 5 and the filling layer 10 tightly into a cable, but also play a fire-resistant role. While setting the material of the tape layer 6 as a fire separation and fire prevention material, it is also necessary to consider the situation where the insulating layer 4 melts when heated at high temperatures. Therefore, the method of setting an inner isolation layer 3 between the fire-resistant layer 2 and the insulating layer 4 is adopted to reduce the damage of the stress deformation generated by the melting of the insulating layer 4 to the fire-resistant layer 2.

[0042] The material of the armor layer 8 is selected to be formed by winding a non-magnetic stainless steel tape to protect the integrity and electrical performance inside the cable. An outer isolation layer 7 is provided between the tape layer 6 and the armor layer 8, which can reduce the damage of the stress deformation generated by the heating of the armor layer 8 to the tape layer 6 or the fire-resistant layer 2.

[0043] The material of the outer protective layer 9 is selected as a low-smoke and halogen-free material, which has a low smoke emission and low toxicity when heated and is safer.

[0044] The material of the filling layer 10 is selected as an inorganic nano refractory filling material, such as an inorganic nano refractory filling rope or an inorganic nano refractory filling wire, which has the characteristics of high temperature resistance, ultra-softness, light specific gravity, high strength, etc., and does not contain harmful substances such as halogen, asbestos, and glass fiber. It has less smoke emission during combustion, meets the requirements of environmental protection and flame retardancy, and is suitable for actual production.

[0045] Refer to Figure 1 and Figure 2 The inner isolation layer 3 includes a layered inner base material 11 and a plurality of mutually parallel inner isolation columns 12. The material of the inner base material 11 is selected as non-woven fabric, and the material of the inner isolation columns 12 is selected as a ceramic material with high heat resistance. The inner isolation columns 12 are fixedly connected to one side of the inner base material 11 facing the insulating layer 4, and the side of the inner isolation columns 12 facing the insulating layer 4 is set to be arc-shaped; during actual production, the inner isolation columns 12 are produced in a wrapping manner, so that a plurality of inner isolation columns 12 are spirally wound and arranged along the length direction of the conductive bundle 5 on the inner base material 11.

[0046] Refer to Figure 1 and Figure 2 The outer isolation layer 7 includes a layered outer base material 13 and a plurality of mutually parallel outer isolation columns 14. The material of the outer base material 13 is selected as non-woven fabric, and the outer isolation columns 14 are fixedly connected to one side of the outer base material 13 facing the armor layer 8; the side of the outer isolation columns 14 facing the armor layer 8 is also set to be arc-shaped; during actual production, the outer isolation columns 14 are also produced in a wrapping manner, so that a plurality of outer isolation columns 14 are spirally wound and arranged along the length direction of the conductive bundle 5 on the outer base material 13.

[0047] Refer to Figure 2 and Figure 3 Between adjacent outer isolation columns 14, a plurality of airbag strips 15 are also filled. The plurality of airbag strips 15 are in butt contact with each other at the head and tail and are not communicated with each other. Each airbag strip 15 includes a plurality of airbags 16, and communicating pipes 17 are connected between every two adjacent airbags 16 at the same time. Each airbag 16 is filled with solid carbon dioxide during production; when the entire cable is produced and the cable is in a normal temperature environment, the solid carbon dioxide will sublimate into carbon dioxide gas, so that the airbags 16 are filled with high-pressure carbon dioxide gas at normal temperature; the wrapping material of the airbags 16 is composed of flammable materials, and when the airbags 16 are burned by an external fire, they will be damaged and release carbon dioxide gas.

[0048] The implementation principle of the 1 kV fire-resistant cable in Embodiment 1 of this application is as follows: When the cable burns under fire and rated voltage, each layer structure inside the cable will withstand a high temperature of at least 750 degrees Celsius. The armor layer 8 may undergo stress deformation due to temperature changes. The outer isolation layer 7 can provide a deformation space to buffer the stress deformation of the armor layer 8. At the same time, the airbag 16 in the outer isolation layer 7 can leak high-pressure carbon dioxide gas after being ignited by an external fire. At the same time, the high-pressure carbon dioxide gas in other airbags 16 on the same airbag strip 15 will also gather at the damaged part under the action of pressure and act together to dilute the oxygen concentration around the cable and inhibit the penetration of the flame, having the ability to prevent or delay the occurrence or spread of the flame. The tape layer 6 itself is a fire-resistant material that can provide further protection for fire prevention and fire resistance. The insulating layer 4 will melt due to heat after being subjected to high temperature. At this time, the inner isolation layer 3 can provide a deformation space for the insulating layer 4 to buffer the stress deformation of the insulating layer 4 and reduce the extrusion damage to the internal fire-resistant layer 2 of the cable. The above three work together to enhance the fire-resistant performance of the cable.

[0049] The above are the preferred embodiments of this application. The protection scope of this application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. 1 kV fire-resistant cable, which sequentially includes a conductive bundle (5), an armor layer (8) and an outer protective layer (9) from inside to outside, wherein the conductive bundle (5) includes a plurality of conductor cores (1) and a filling layer (10), and each conductor core (1) is sequentially wrapped with a fire-resistant layer (2) and an insulating layer (4) from inside to outside, characterized in that: A tape layer (6) with fire separation and fire prevention performance is provided between the conductive bundle (5) and the armor layer (8). At the same time, an inner isolation layer (3) for isolating the insulation layer (4) and the fire-resistant layer (2) is provided between the fire-resistant layer (2) and the insulation layer (4). The inner isolation layer (3) includes a layered inner base material (11) and a number of heat-resistant inner isolation columns (12) arranged at intervals. The inner isolation columns (12) are uniformly fixed on the side of the inner base material (11) facing the insulation layer (4). A number of the inner isolation columns (12) are spirally wound and arranged along the length direction of the conductive bundle (5). An arc surface is provided on the side wall of the inner isolation column (12) facing the insulation layer (4), and the arc surface abuts against the insulation layer (4). An outer isolation layer (7) is provided between the tape layer (6) and the armor layer (8). The outer isolation layer (7) includes a layered outer base material (13) and a number of outer isolation columns (14) arranged at intervals. The outer isolation columns (14) are uniformly fixed on the side of the outer base material (13) facing the armor layer (8). A number of the outer isolation columns (14) are spirally wound and arranged along the length direction of the conductive bundle (5). A number of air bags (16) for assisting in fire extinguishing are provided between adjacent two of the outer isolation columns (14). Solid carbon dioxide for reducing the fire is filled in the air bags (16).

2. The 1 kV fire-resistant cable according to claim 1, characterized in that: A communication pipe (17) for connecting them is provided between two adjacent air bags (16).

3. The fire-resistant cable of 1 kV according to claim 2, characterized in that: A number of interconnected air bags (16) can form an air bag strip (15). A number of end-to-end air bag strips (15) are filled between every two adjacent outer isolation columns (14). At the same time, the air bag strips (15) are not interconnected with each other.

4. The fire-resistant cable of 1 kV according to claim 1, characterized in that: The fire-resistant layer (2) is a synthetic fluorophlogopite tape.

5. The fire-resistant cable of 1 kV according to claim 1, characterized in that: The filling layer (10) is an inorganic nano fire-resistant rope.

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