Flexible mineral-insulated fire-resistant cable

Abstract

The utility model discloses a kind of flexible mineral insulation fireproof cables, the flexible mineral insulation fireproof cable includes outer sheath layer, metal sheath layer, fireproof insulation layer, fire-retardant filling layer, fireproof insulation layer and several cable core units, several cable core units are covered in fireproof insulation layer, the gap between the periphery of each cable core unit and the inside of fireproof insulation layer is filled with the fire-retardant filling layer, the fireproof insulation layer is covered in the periphery, the metal sheath layer is covered in the periphery of fireproof insulation layer, the outer sheath layer is covered in the periphery of metal sheath layer, the metal sheath layer is made of corrugated pipe sheath layer by metal band continuous welding rolling pattern.The flexible mineral insulation fireproof cable of the utility model has excellent fireproof performance, flexibility, corrosion resistance and long life etc. Characteristics, and can effectively block the damage of flame or high temperature to cable core conductor, improve the safety performance of cable use.

Description

Technical Field

[0001] The utility model belongs to the technical field of cables, and particularly relates to a flexible mineral insulated fireproof cable. Background Art

[0002] Cables are mainly used for power conduction. There are various types of cables and their applications are becoming increasingly widespread. The insulating materials of cables usually use organic polymer materials. Under flame conditions, organic materials will quickly carbonize, resulting in the destruction of the insulation level until the loss of insulation function. Thus, a cable insulated with minerals has been developed; Mineral insulated cable is a cable with a copper conductor core wire wrapped by a copper sheath and an inorganic insulating material separating the conductor and the sheath. Although mineral insulated cables have good insulation properties and high efficiency in fire prevention, water prevention, corrosion prevention, etc. However, the existing mineral insulated cables have problems such as unstable use, poor flexibility, hard cables, difficult construction, and are not easy to install and lay. Moreover, the manufacturing cost is relatively high. Therefore, it is of great significance to develop a flexible mineral insulated fireproof cable with lower production cost and better performance to replace traditional rigid fireproof cables. <able> Content of the Utility Model

[0003] The purpose of the utility model is to provide a flexible mineral insulated fireproof cable. The flexible mineral insulated fireproof cable of the utility model has excellent fireproof performance, flexibility, corrosion resistance and long life, etc. Moreover, it can effectively block the damage of flames or high temperatures to the cable core conductor and improve the safety performance of cable use. To achieve the above purpose, the following technical solutions are adopted: According to one aspect of the utility model, the utility model provides a flexible mineral insulated fireproof cable. The flexible mineral insulated fireproof cable includes an outer sheath layer, a metal sheath layer, a refractory insulation layer, a flame retardant filling layer, a fireproof insulation layer and a plurality of cable core units. A plurality of cable core units are covered in the fireproof insulation layer, and the flame retardant filling layer is filled in the gap between the periphery of each cable core unit and the inside of the fireproof insulation layer. The refractory insulation layer is covered outside the fireproof insulation layer, the metal sheath layer is covered outside the refractory insulation layer, and the outer sheath layer is covered outside the metal sheath layer.

[0004] Preferably, the above solution is further improved as follows: the metal sheath layer is a corrugated sheath layer made by continuously welding and corrugating a metal strip. Among them, the depth of the welding corrugation is 1 mm to 3 mm, and the corrugation pitch is 3 to 10 mm.

[0005] Preferably, the above solution is further improved as follows: the corrugated sheath layer is made by continuously welding and corrugating a copper strip with a thickness of 0.2 to 1.5 mm. A plurality of concave notches are arranged on the outer peripheral surface of the wave crest of the corrugated sheath along the axial direction.

[0006] Further preferably, in the above solution, the thickness of the outer sheath layer is 1 - 2.5 mm, and the flame-retardant filling layer is made of a nano-carbon fiber fireproof silicone rubber insulating material.

[0007] Further preferably, in the above solution, the fire-resistant insulating layer is formed by concentrically winding multiple layers of inorganic mineral fire-resistant synthetic mica tape in an overlapping manner. The thickness ratio of the fireproof insulating layer to the fire-resistant insulating layer is 1:3, and the thickness of the fireproof insulating layer is 0.3 mm - 1 mm.

[0008] Further preferably, in the above solution, the cable core unit includes a core conductor, and a shielding layer, an inner flame-retardant layer, and an inner sheath layer that are coated on the core conductor from the inside out.

[0009] Further preferably, in the above solution, the core conductor is composed of a central conductor, multiple layers of inner conductors surrounding the central conductor, and an outer conductor surrounding the inner conductors. Each layer of inner conductors is formed by arranging multiple identical circular conductors in a circular and tightly arranged manner, and the outer conductor is formed by tightly distributing shaped wire conductors with a fan-shaped cross-section.

[0010] Further preferably, in the above solution, the shielding layer is a metal braided layer, and the metal braided layer is woven from copper wires with a weaving density not less than 80%.

[0011] Further preferably, in the above solution, the inner flame-retardant layer is made of a nano-ceramic fireproof and fire-resistant silicone rubber material with a thickness of 45 nm - 150 nm. <​​​​​​​​​​​​​​Figure 2 It is a schematic cross-sectional structure diagram of a flexible mineral insulated fireproof cable of the present utility model; Figure 3 It is a schematic structure diagram of the cable core unit of the present utility model; In the drawings, the outer sheath layer 1, the metal sheath layer 2, the fireproof insulation 3, the flame retardant filling layer 4, the cable core unit 5, the fireproof insulation 6, the concave notch 20, the core conductor 50, the central conductor 50a, the inner conductor 50b, the outer conductor 50c, the shielding layer 51, the inner flame retardant layer 52, and the inner sheath layer 53. Specific embodiments

[0015] To make the purpose, technical solutions and advantages of the present utility model clearer and more understandable, the following gives preferred embodiments by referring to the attached drawings and further elaborates on the present utility model in detail. However, it should be noted that many details listed in the specification are only for enabling the reader to have a thorough understanding of one or more aspects of the present utility model, and these aspects of the present utility model can also be realized even without these specific details.

[0016] Combined with Figure 1 and Figure 2 As shown, according to a flexible mineral insulated fireproof cable of the present utility model, the flexible mineral insulated fireproof cable includes an outer sheath layer 1, a metal sheath layer 2, a fireproof insulation layer 3, a flame retardant filling layer 4, a fireproof insulation layer 6 and a plurality of cable core units 5. A plurality of cable core units 5 are covered in the fireproof insulation layer 6, and the flame retardant filling layer 4 is filled in the gap between the periphery of each cable core unit 5 and the inside of the fireproof insulation layer 6. The fireproof insulation layer 3 is covered on the periphery of the fireproof insulation layer 6, the metal sheath layer 2 is covered on the periphery of the fireproof insulation layer 3, and the outer sheath layer 1 is covered on the periphery of the metal sheath layer 2.

[0017] In the present utility model, combined with Figure 1 and Figure 2 As shown, the metal sheath layer 2 is a corrugated sheath layer made of continuously welded and corrugated metal strips. Among them, the depth of the welded corrugation is 1 mm to 3 mm, and the corrugation pitch is 3 to 10 mm; the corrugated sheath layer is made of continuously welded and corrugated copper strips with a thickness of 0.2 to 1.5 mm; a spiral corrugated groove is formed by continuous welding and rolling, so that the cable has enough expansion and contraction space during the bending process, thus realizing the true flexible function of the cable. A plurality of concave notches 20 are provided on the outer peripheral surface of the wave crest of the corrugated sheath and along the axial direction. When the outer sheath layer 1 is co-extruded and cast on the surface of the metal sheath layer 2, the high-temperature molten material of the sheath layer 1 is poured into the corrugations and the concave notches 20, making the sheath layer 1 more compact and reducing the torsion of the outer sheath layer 1 on the outer periphery of the metal sheath layer 2.

[0018] In the present utility model, combined with Figure 1 and Figure 2As shown, the thickness of the outer sheath layer 1 is 1 mm to 2.5 mm. The outer sheath layer 1 is made of an environment-friendly low-smoke and halogen-free flame-retardant polyolefin material. Specifically, ethylene-vinyl acetate copolymer (ethylene-vinyl acetate copolymer, abbreviated as EVA plastic) is used, which has good flexibility, no corrosive gas, and can reduce the smoke hazard and inhibit the spread of flames. The flame-retardant filling layer 4 is made of a nano-carbon fiber fire-proof silicone rubber insulating material with a diameter of 10 - 50 nm. The carbon fibers dispersed in the silicone rubber matrix can form a dense network, effectively blocking the heat and flame propagation, and playing an effective fire-proof role.

[0019] In the present utility model, in combination with Figure 1 and Figure 2 As shown, the refractory insulation layer 3 is formed by multi-layer overlapping and concentric winding of an inorganic mineral refractory synthetic mica tape. The inorganic mineral refractory synthetic mica tape is overlapped and wound 2 - 5 layers. The melting point of the inorganic mineral refractory synthetic mica tape is as high as 1200 - 1300 °C. Even during combustion, it does not produce any harmful gases or combustion products. The cable will not have a self-ignition phenomenon, nor will it cause secondary pollution. It will not easily melt under an external high-temperature flame, greatly enhancing its temperature resistance and fire-proof level, thereby improving its safety performance and service life. At the same time, the metal sheath layer 2 is continuously welded and rolled to form a spiral corrugation and wrapped around the periphery of the refractory insulation layer 3, enabling the metal sheath layer 2 and the refractory insulation layer 3, as well as the refractory insulation layer 3 and the fire-proof insulation layer 6, to be more tightly wrapped together. By setting the inorganic mineral refractory synthetic mica tape, the flexibility of the fire-proof cable can be enhanced, reducing the breakage of the cable during use, and improving the fire-proof and insulation performance, as well as the use safety. The thickness ratio of the fire-proof insulation layer 6 to the refractory insulation layer 3 is 1:3, and the thickness of the fire-proof insulation layer 6 is 0.3 mm - 1 mm. The fire-proof insulation layer is made of a ceramized refractory fiber material. The ceramized refractory fiber material has very stable performance, is soft at room temperature and has good elasticity, is resistant to ultraviolet rays and heat aging, has a high ignition point, and has strong fire-proof performance. When burning, it does not emit any toxic and harmful gases. The fire-proof insulation layer can significantly improve the fire-proof, refractory and mechanical properties of the cable.

[0020] In the present utility model, in combination with Figure 2 and Figure 3As shown, the cable core unit 5 includes a core conductor 50, a shielding layer 51, an inner flame-retardant layer 52, and an inner sheath layer 53 that are coated on the core conductor 50 from the inside out; the core conductor 50 is composed of a central conductor 50a, multiple layers of inner conductors 50b surrounding the central conductor 50a, and an outer conductor 50c surrounding the inner conductors 50b; each layer of the inner conductor 50b is formed by arranging multiple identical circular conductors in a circular and tightly arranged manner, and the outer conductor 50c is formed by tightly distributing profile conductors with a fan-shaped cross-section; the central conductor 50a, the inner conductor 50b, and the outer conductor 50c are tightly pressed and stranded by single-wire metal conductors, and the single-wire metal conductors are copper wires, aluminum wires, or aluminum alloy wires, etc. The cross-section of the outer conductor 50c is fan-shaped and is coated on the outer periphery of the inner conductor 50b. The contact gap between adjacent outer conductors 50b is smaller. When the shielding layer 51 is coated on the outer periphery of the outer conductor 50c, it can increase the contact surface area between the shielding layer 51 and the outer conductor 50c, ensuring that the shielding layer 51 is more tightly and smoothly coated on the outer peripheral surface of the outer conductor 50c.

[0021] In the present utility model, the shielding layer 51 is a metal braided layer, and the metal braided layer is woven from copper wires with a braiding density of not less than 80%. The metal braided layer structure is soft and can also play a shielding role to prevent electronic interference between the flexible cable and the outside world, and can reduce the influence of external electromagnetic signals on the cable; the inner flame-retardant layer 52 is made of a nano-ceramic fireproof and refractory silicone rubber material with a thickness of 45nm to 150nm; the nano-ceramic fireproof and refractory silicone rubber material has the characteristics of flame retardancy, high temperature resistance, cold resistance, resistance to acids, alkalis, and corrosive gases, and waterproofness. It is soft and elastic at room temperature, making the cable have a good flexible structure, and can also play a role in high-temperature fire resistance and heat insulation; it ensures that the cable has good fire resistance, bending performance, insulation performance, high breakdown voltage, large heat resistance index, tensile strength to prevent mechanical damage, resistance to strong electromagnetic interference, and strong electrostatic interference.

[0022] The above are only the preferred embodiments of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present utility model.

Claims

1. A flexible mineral-insulated fire-resistant cable, characterized in that: The flexible mineral-insulated fireproof cable includes an outer sheath layer (1), a metal sheath layer (2), a fire-resistant insulation layer (3), a flame-retardant filling layer (4), a fireproof insulation layer (6), and several cable core units (5). Several cable core units (5) are wrapped inside the fireproof insulation layer (6). The gap between the periphery of each cable core unit (5) and the interior of the fireproof insulation layer (6) is filled with the flame-retardant filling layer (4). The fire-resistant insulation layer (3) is wrapped around the fireproof insulation layer (6). The metal sheath layer (2) is wrapped around the fire-resistant insulation layer (3). The outer sheath layer (1) is wrapped around the metal sheath layer (2).

2. The flexible mineral-insulated fire-resistant cable according to claim 1, characterized in that: The metal sheath layer (2) is a corrugated pipe sheath layer made of metal strip continuously welded and rolled, wherein the depth of the welded and rolled lines is 1mm to 3mm and the spacing between the lines is 3mm to 10mm.

3. A flexible mineral-insulated fire-resistant cable according to claim 2, characterized in that: The corrugated pipe sheath is made of 0.2mm to 1.5mm thick copper strip continuously welded and rolled, and the outer peripheral surface of the corrugated pipe sheath is provided with multiple recessed notches (20) along the axial direction.

4. A flexible mineral-insulated fire-resistant cable according to claim 1, characterized in that: The outer sheath layer (1) has a thickness of 1mm to 2.5mm, and the flame-retardant filling layer is made of nano-grade carbon fiber fireproof silicone rubber insulation material.

5. A flexible mineral-insulated fire-resistant cable according to claim 1, characterized in that: The fire-resistant insulation layer (3) is formed by multiple layers of inorganic mineral refractory synthetic mica tape wrapped concentrically. The thickness ratio of the fireproof insulation layer (6) to the fire-resistant insulation layer (3) is 1:3, and the thickness of the fireproof insulation layer (6) is 0.3mm-1mm.

6. A flexible mineral-insulated fire-resistant cable according to claim 1, characterized in that: The cable core unit (5) includes a conductor core (50) and a shielding layer (51), an inner flame-retardant layer (52), and an inner sheath layer (53) that are wrapped around the conductor core (50) from the inside out.

7. A flexible mineral-insulated fire-resistant cable according to claim 6, characterized in that: The conductor core (50) consists of a center conductor (50a), multiple inner conductors (50b) surrounding the center conductor (50a), and an outer conductor (50c) surrounding the inner conductors (50b). Each inner conductor (50b) is composed of multiple identical circular conductors arranged in a circular and close arrangement, and the outer conductor (50c) is composed of closely distributed conductors with a fan-shaped cross-section.

8. A flexible mineral-insulated fire-resistant cable according to claim 6, characterized in that: The shielding layer (51) is a metal braided layer, which is made of copper wire and has a braiding density of not less than 80%.

9. A flexible mineral-insulated fire-resistant cable according to claim 6, characterized in that: The inner flame-retardant layer (52) is made of nano-scale ceramicized fire-resistant and fire-retardant silicone rubber material of 45nm to 150nm.

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