Flame-retardant cable

Abstract

The embodiment of the utility model provides a flame-retardant cable. The flame-retardant cable comprises a plurality of insulated conductor structures, and each insulated conductor structure comprises a conductor and a crosslinked polyethylene insulating layer. Flame-retardant fillers are arranged among the insulated conductor structures; the outer layers of the insulated conductor structures and the flame-retardant filler are coated with a halogen-free low-smoke flame-retardant wrapping tape; the outer layer of the halogen-free low-smoke flame-retardant wrapping tape is coated with a halogen-free low-smoke oxygen barrier layer; the outer layer of the halogen-free low-smoke oxygen barrier layer is coated with a steel wire armor layer; and the outer layer of the steel wire armor layer is coated with a halogen-free low-smoke flame-retardant polyolefin outer protective layer. In this way, the cable has a better flame-retardant characteristic, the spreading speed of flames can be effectively slowed down, no halogen acid gas is released when the cable is burnt, and the harm of fire disasters to human bodies is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of power cable, and more particularly, to a flame-retardant cable. BACKGROUND

[0002] The current standard of mine cable gives the standard of flame-retardant cable, and the flame-retardant cable is the cable that the sample is burned under the prescribed test condition, the flame spreads only in the limited range after the test fire source is removed, and the afterflame can be self-extinguished within the limited time.

[0003] However, the common flame-retardant cable on the market is the flame-retardant cable with PVC as the main sheath material, and such cable material is generally a halogen-containing high polymer material, which will generate a large amount of smoke and release toxic gases such as halogen acid gas when the flame-retardant cable catches fire, causing serious harm to the human body after inhalation and resulting in casualties. CONTENT OF THE UTILITY MODEL

[0004] According to the embodiment of the utility model, a kind of flame-retardant cable is provided.The cable can effectively slow down the spread speed of flame when suffering high temperature, avoid generating toxic and harmful substances, and reduce the harm of fire to human body.

[0005] A kind of flame-retardant cable includes several insulated conductor structures, each of the insulated conductor structures includes a conductor and a cross-linked polyethylene insulation layer;Flame-retardant filler is arranged between the insulated conductor structures;The outer layer of the insulated conductor structure and the flame-retardant filler is covered with halogen-free low-smoke flame-retardant tape;The outer layer of the halogen-free low-smoke flame-retardant tape is covered with halogen-free low-smoke oxygen barrier layer;The outer layer of the halogen-free low-smoke oxygen barrier layer is covered with steel wire armor layer;The outer layer of the steel wire armor layer is covered with halogen-free low-smoke flame-retardant polyolefin outer protective layer.

[0006] Further, the insulated conductor structure further includes a conductor shielding layer;The conductor shielding layer is arranged between the conductor and the cross-linked polyethylene insulation layer.

[0007] Further, the insulated conductor structure further includes an insulation shielding layer;The insulation shielding layer is covered outside the cross-linked polyethylene insulation layer.

[0008] Further, the insulated conductor structure further includes a metal shielding layer;The metal shielding layer is covered outside the insulation shielding layer.

[0009] Further, the cross section of the conductor is circular or sector.

[0010] Further, if the cross section of the conductor is circular, the number of the insulated conductor structures is 3, and each of the insulated conductor structures is tangent, and the flame-retardant filler is filled between the insulated conductor structure and the halogen-free low-smoke flame-retardant tape.

[0011] Furthermore, if the cross-section of the conductor is sector-shaped, then the two straight sides of each sector are connected to the straight sides of the adjacent sector, and the flame-retardant filler is disposed at the center of all insulating conductor structures and abuts against the central angle of the insulating conductor structure. Attached Figure Description

[0012] The above and other features, advantages, and aspects of the various embodiments of the present invention will become more apparent from the accompanying drawings and the following detailed description. In the drawings, the same or similar reference numerals denote the same or similar elements, wherein:

[0013] Figure 1 A cross-sectional schematic diagram of a flame-retardant cable according to an embodiment of the present invention is shown;

[0014] Figure 2 A cross-sectional schematic diagram of a flame-retardant cable according to another embodiment of the present invention is shown;

[0015] Among them, 1 is a conductor, 2 is a conductor shielding layer, 3 is a cross-linked polyethylene insulation layer, 4 is an insulation shielding layer; 5 is a metal shielding layer, 6 is a flame-retardant filler, 7 is a halogen-free low-smoke flame-retardant wrapping tape, 8 is a halogen-free low-smoke oxygen barrier layer, 9 is a steel wire armor layer, and 10 is a halogen-free low-smoke flame-retardant polyolefin outer sheath. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0017] Example 1

[0018] like Figure 1 The diagram shown is a cross-sectional view of the flame-retardant cable according to an embodiment of the present invention.

[0019] A flame-retardant cable includes a plurality of insulated conductor structures, each of the insulated conductor structures including a conductor 1 and a cross-linked polyethylene insulation layer 3.

[0020] In the embodiment, the cross section of the conductor 1 is a sector, and the insulation conductor structure formed by the conductor 1 is also a sector, and the number of the sector insulation conductor structure can be 3 or 4; when the number of the sector insulation conductor structure is 3, the cross section of each sector insulation conductor structure is an equal cross section, that is, the angle of each sector is 120 degrees. When the number of the sector insulation conductor structure is 4, there are two cases; the first case: the cross section of each sector insulation conductor structure is an equal cross section, that is, the angle of each sector is 90 degrees. The second case: the cross section of 3 sector insulation conductor structures is an equal cross section, and the cross section of 1 sector insulation conductor structure is not the same as the cross section of the other 3 sector insulation conductor structures. For example, the angle of the sector of the cross section of 1 sector insulation conductor structure is 60 degrees, which is less than the angle of the sector of the cross section of the other 3 sector insulation conductor structures which is 100 degrees. In the above two cases, the two straight edges of each sector insulation conductor structure are connected with the straight edges of the adjacent sector insulation conductor structure.

[0021] In the embodiment, the conductor 1 is, for example, an electric core of WD-MYJY43 model; the rated voltage is 0.6 / 1KV. The conductor satisfies the requirements of surface finish, no oil stain, no damage to the shielding machine insulation burr, sharp edge, no protrusion or broken single wire.

[0022] In the embodiment, the cross-linked polyethylene insulation layer 3 is polyethylene under the action of high-energy rays (such as gamma rays, alpha rays, electron rays, etc.) or cross-linking agent, so that cross-linking is generated between the macromolecules, which can improve its heat resistance and other properties. The long-term working temperature of the cable using cross-linked polyethylene as insulation can be increased to 90℃, and the instantaneous short-circuit temperature that can be withstood can reach 170-250℃.

[0023] In the embodiment, the flame-retardant filler 6 is arranged between the insulation conductor structures.

[0024] As an embodiment of the embodiment, as shown in Figure 1 The flame-retardant filler can be arranged at the center of all sector insulation conductor structures and abut the central angle of the sector insulation conductor structure; the flame-retardant filler includes an extruded filler strip of flame-retardant polyolefin material, a glass fiber filler rope, etc.

[0025] Further, as shown in Figure 1As shown, the outer layer of the insulation conductor structure and the flame-retardant filler 6 is wrapped with a halogen-free low-smoke flame-retardant tape 7; the halogen-free low-smoke flame-retardant tape is made by impregnating a flame-retardant glue without any halogen on a glass fiber tape and curing, has high flame retardancy, is non-toxic and non-corrosive, and has low smoke density. It is suitable for various low-smoke halogen-free flame-retardant cables, fire-resistant cable cores and cable winding.

[0026] Further, as shown in Figure 1 , the outer layer of the halogen-free low-smoke flame-retardant tape 7 is wrapped with a halogen-free low-smoke oxygen barrier layer 8; the halogen-free low-smoke oxygen barrier layer is made by extruding a thermoplastic low-smoke halogen-free flame-retardant polyolefin oxygen barrier filler, which has excellent low-smoke performance, halogen-free performance, flame-retardant performance, self-extinguishing performance, and does not drip after burning, is completely adhered to the cable to form a hard carbon shell layer, and has the effects of isolating oxygen and heat, preventing burning, and completely protecting the cable.

[0027] Further, as shown in Figure 1 , the outer layer of the halogen-free low-smoke oxygen barrier layer 8 is wrapped with a steel wire armor layer 9; the steel wire armor refers to a protective layer made by braiding steel wires on the outer layer of a cable or a pipeline. It mainly plays the roles of protecting the cable or the pipeline and improving the wear resistance and external force damage resistance of the cable or the pipeline. In different cables and pipelines, the forms of the steel wire armor are also different, such as thick steel wire armor and thin steel wire armor. The cable or the pipeline with thick steel wire armor has high tensile strength and extrusion resistance, can be used for a long time in a relatively harsh environment, and has good corrosion resistance. The cable or the pipeline with thin steel wire armor has high flexibility and bending performance, and is suitable for use in curved terrain or small-radius bending.

[0028] In the embodiment, the steel wire of the steel wire armor is low-carbon galvanized steel wire.

[0029] Further, as shown in Figure 1 , the outer layer of the steel wire armor layer 9 is wrapped with a halogen-free low-smoke flame-retardant polyolefin outer protective layer 10. The halogen-free low-smoke flame-retardant polyolefin outer protective layer is made of high-flame-retardant thermoplastic low-smoke halogen-free flame-retardant sheath material, which has good flame-retardant performance, good self-extinguishing performance, low smoke release, and good crack resistance.

[0030] Embodiment 2

[0031] As shown in Figure 2 , it is a cross-sectional schematic view of a flame-retardant cable according to another embodiment of the utility model.

[0032] A flame-retardant cable includes a plurality of insulated conductor structures, each of the insulated conductor structures including a conductor 1 and a cross-linked polyethylene insulation layer 3.

[0033] In this embodiment, the conductor can be one or more conductive wire cores with a circular cross-section; an insulated conductor structure is formed by covering the conductor as the core with a cross-linked polyethylene insulation layer 3. For example... Figure 2 As shown, there are 3 insulating conductor structures; and each of the insulating conductor structures is tangent to the others.

[0034] In this embodiment, the conductor is, for example, a WD-MYJY43 type battery cell with a rated voltage of 8.7 / 10KV. The conductor meets the requirements of having a smooth surface, no oil stains, no burrs or sharp edges that damage the shielding and insulation, and no protrusions or breaks in the single wires.

[0035] In this embodiment, the cross-linked polyethylene insulation layer 3 is formed by cross-linking between the macromolecules of polyethylene under the action of high-energy rays (such as gamma rays, alpha rays, electron rays, etc.) or cross-linking agents, which can improve its heat resistance and other properties. Cables using cross-linked polyethylene as insulation can have a long-term operating temperature of up to 90°C and can withstand instantaneous short-circuit temperatures of 170-250°C. For example, XLPE cables.

[0036] Furthermore, such as Figure 2 As shown, the insulated conductor structure further includes a conductor shielding layer 2; the conductor shielding layer 2 is disposed between the conductor 1 and the cross-linked polyethylene insulation layer 3. The conductor shielding layer 2 is made of a semi-conductive material, tightly extruded onto the conductor, with a smooth surface, no obvious stranding marks, and no sharp corners or particles.

[0037] The conductive core is composed of multiple single wires. During the production process, gaps may exist between the single wires of the conductive core, and the surface may be uneven, which increases the surface electric field intensity. The main function of the conductor shielding layer is to eliminate the unevenness of the conductor surface, eliminate the sharp point effect of the conductor surface, eliminate the gaps between the conductor and the insulation, make a tight contact between the conductor and the insulation, and improve the electric field distribution around the conductor. For cross-linked cable conductor shielding layers, it also has the functions of inhibiting electric tree growth and thermal shielding.

[0038] Furthermore, the insulated conductor structure also includes an insulating shielding layer 4; the insulating shielding layer 4 covers the outside of the cross-linked polyethylene insulating layer. The insulating shielding layer 4 is an extruded semi-conductive layer.

[0039] The function of the insulation shielding layer is to provide a transition between the main cable insulation and the grounding metal shield, ensuring tight contact and eliminating gaps between the insulation and the grounding conductor; to eliminate the tip effect on the surface of the grounding copper tape; and to improve the electric field distribution around the insulation surface.

[0040] In the embodiment, the insulating shield is of a peelable type, and the peelable insulating shield has good adhesion and no semiconductive particles are left after peeling.

[0041] Further, the insulating conductor structure further comprises a metal shield layer 5; the metal shield layer 5 is wrapped outside the insulating shield layer. The metal shield layer 5 is a copper tape shield layer structure, which is composed of overlapped and wrapped soft copper tapes, and the thickness of the copper tape is 0.1 mm.

[0042] In the embodiment, the metal shield layer is wrapped outside the insulating shield layer, and the metal shield layer adopts copper tapes, which is a key structure for limiting electric field in the cable and protecting personal safety, and is also a grounding shield layer for protecting the cable from external electrical interference. When a grounding or short circuit fault occurs in the system, the metal shield layer is a channel for short circuit grounding current.

[0043] Further, as shown in Figure 2 the outer layer of the insulating conductor structure is wrapped with a halogen-free low-smoke flame-retardant tape 7; the halogen-free low-smoke flame-retardant tape is formed by impregnating a flame-retardant glue without any halogen on a glass fiber tape and curing, and has high flame retardancy, non-toxicity, non-corrosivity and low smoke density. It is suitable for various low-smoke halogen-free flame-retardant cables, fire-resistant cable cores and cable winding. The halogen-free low-smoke flame-retardant tape 7 can make the cable appearance round and ensure that the cable core is tight and not loose. It has high use value for winding of flame-retardant cables, fire-resistant cables, low-smoke halogen-free cables, marine cables, mining cables, crosslinked flame-retardant cables and large cross-section cables, is easy to wind, is not affected by temperature difference and humidity, and is a good ideal winding protective layer material in flame-retardant fire-resistant cable production.

[0044] Further, a flame-retardant filler 6 is arranged between the insulating conductor structure and the halogen-free low-smoke flame-retardant tape 7. The flame-retardant filler comprises an extruded filler strip of flame-retardant polyolefin material, a glass fiber filler rope and the like. Figure 2 As shown in

[0045] Further, as shown in Figure 2 the outer layer of the halogen-free low-smoke flame-retardant tape 7 is wrapped with a halogen-free low-smoke oxygen barrier layer 8; the halogen-free low-smoke oxygen barrier layer is formed by extruding a thermoplastic low-smoke halogen-free flame-retardant polyolefin oxygen barrier layer filler, which has excellent low-smoke performance, halogen-free performance, flame-retardant performance, fire-resistance performance, and after burning, does not drip, is completely adhered to the cable, forms a hard carbon shell layer, insulates oxygen and heat, and prevents burning, and has the effect of completely protecting the cable.

[0046] Further, as shown in Figure 2As shown, the outer layer of the halogen-free low-smoke oxygen barrier layer 8 is covered with a steel wire armor layer 9. The steel wire armor refers to a protective layer formed by braiding steel wires on the outer layer of a cable or a pipeline. In this embodiment, the steel wires of the steel wire armor are made of low-carbon galvanized steel wires. The steel wire armor mainly plays a role in protecting the cable or pipeline and improving the wear resistance and external force damage resistance of the cable or pipeline. In different cables and pipelines, the forms of the steel wire armor are also different, such as thick steel wire armor and thin steel wire armor. The cable or pipeline with thick steel wire armor has high tensile strength and extrusion resistance, can be used in harsh environments for a long time, and has good corrosion resistance. The cable or pipeline with thin steel wire armor has high flexibility and bending performance, and is suitable for use in curved terrain or small radius bending.

[0047] The halogen-free low-smoke oxygen barrier layer 8 is arranged between the halogen-free low-smoke flame-retardant wrapping tape 7 and the steel wire armor layer 9, which is implemented according to the relevant national standards. According to the relevant national standards, an isolation sleeve should be extruded between the 8.7 / 10kV power cable core and the armor layer to separate the copper tape from the armor layer. In this embodiment, the halogen-free low-smoke oxygen barrier layer 8 plays a role equivalent to the isolation sleeve.

[0048] Further, as shown in the figure, Figure 2 The outer layer of the steel wire armor layer 9 is covered with a halogen-free low-smoke flame-retardant polyolefin outer protective layer 10. The halogen-free low-smoke flame-retardant polyolefin outer protective layer is made of high-flame-retardant thermoplastic low-smoke halogen-free flame-retardant sheath material, which has good flame-retardant performance, good self-extinguishing property, low smoke release, and anti-cracking advantage.

[0049] The outer layer of the steel wire armor layer 9 is covered with a halogen-free low-smoke flame-retardant polyolefin outer protective layer 10, which is implemented according to the relevant national standards. The national standard requires that the 8.7 / 10kV power cable should have an outer sheath outside the armor. In this embodiment, the halogen-free low-smoke flame-retardant polyolefin outer protective layer 10 is arranged as the outer sheath corresponding to the national standard.

[0050] According to the embodiment of the utility model, the insulating layer, sheath, outer protective layer and auxiliary material (wrapping tape and filling) of the flame-retardant cable do not contain halogen elements such as fluorine, chlorine, bromine and iodine, and heavy metal elements such as mercury, chromium, cadmium and lead which have great pollution to the environment are excluded in the manufacturing process, not only have better flame-retardant characteristics, can effectively slow down the spread speed of flame, and no halogen acid gas is discharged when the cable burns, reducing the harm of fire to human body.

[0051] When a fire occurs, the smoke generated by the flame-retardant cable has a light transmittance greater than 60%, and the cable also has a small smoke emission, which can provide better visibility and escape time and reduce personnel casualties.

[0052] The specific embodiments described above do not constitute a limitation on the protection scope of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A flame-retardant cable, characterized in that, It includes several insulating conductor structures, each of which includes a conductor (1) and a cross-linked polyethylene insulation layer (3); a flame-retardant filler (6) is disposed between the insulating conductor structures; the insulating conductor structures and the flame-retardant filler (6) are covered with a halogen-free low-smoke flame-retardant wrapping tape (7); the halogen-free low-smoke flame-retardant wrapping tape (7) is covered with a halogen-free low-smoke oxygen barrier layer (8); the halogen-free low-smoke oxygen barrier layer is covered with a steel wire armor layer (9); the steel wire armor layer is covered with a halogen-free low-smoke flame-retardant polyolefin outer sheath layer (10).

2. The flame-retardant cable according to claim 1, characterized in that, The insulated conductor structure further includes a conductor shielding layer (2); the conductor shielding layer (2) is disposed between the conductor (1) and the cross-linked polyethylene insulation layer (3).

3. The flame-retardant cable according to claim 2, characterized in that, The insulating conductor structure further includes an insulating shielding layer (4); the insulating shielding layer (4) covers the outside of the cross-linked polyethylene insulating layer (3).

4. The flame-retardant cable according to claim 3, characterized in that, The insulating conductor structure further includes a metal shielding layer (5); the metal shielding layer (5) covers the outside of the insulating shielding layer (4).

5. The flame-retardant cable according to claim 1, characterized in that, The conductor (1) has a circular or fan-shaped cross-section.

6. The flame-retardant cable according to claim 5, characterized in that, If the cross-section of the conductor (1) is circular, then the number of the insulating conductor structures is 3, and each of the insulating conductor structures is tangent to the other. The flame-retardant filler (6) is filled between the insulating conductor structure and the halogen-free low-smoke flame-retardant wrapping tape (7).

7. The flame-retardant cable according to claim 5, characterized in that, If the cross-section of the conductor is sector-shaped, then the two straight sides of each sector are connected to the straight sides of the adjacent sector, and the flame-retardant filler is disposed at the center of all insulating conductor structures and abuts against the central angle of the insulating conductor structure.

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