Crosslinked polyethylene insulated low-smoke halogen-free flame-retardant fireproof power cable

Abstract

The invention discloses a crosslinked polyethylene insulated low-smoke halogen-free flame-retardant fireproof power cable, which relates to the technical field of cables, and specifically comprises a cable inner core, the cable inner core is of a layered structure, the cable inner core comprises a shielding net and a cable conductor arranged in the shielding net, the cable conductor is in a spiral shape, and the shielding net is arranged in the cable conductor. The shielding net comprises metal rings which are uniformly distributed, every two adjacent metal rings are connected through a metal wire, and the metal wires are wavy; an isolating layer is wound outside the cable inner core, a heat dissipation gap is formed between the isolating layer and the cable inner core, and a cable protection layer is coated outside the isolating layer. According to the cable, the isolation layer is arranged between the cable inner core and the cable protection layer, so that heat on the cable inner core can be quickly discharged, the heat is prevented from being accumulated in the cable inner core, the probability that the cable is damaged due to heat accumulation is reduced, the service life of the cable is prolonged, and the water-blocking and flame-retardant performance of the cable is improved.

Description

TECHNICAL FIELD

[0001] The application relates to the cable technology field, in particular to a cross-linked polyethylene insulation low-smoke halogen-free flame-retardant fire-resistant power cable. BACKGROUND

[0002] The development of the flame-retardant fire-resistant power cable started in the 1970s, and it has the functions of excellent fire resistance, non-spreading and maintaining normal power operation for a certain time in the case of fire, the flame resistance of the cable means that the cable can delay and postpone the spread and extension of the flame along the cable, and the cable has the characteristics of self-extinguishing after being ignited. In general, the cable product does not continue to burn or burns for a very short time after the fire source is extinguished when the cable product is ignited by itself or by an external heat source. The cable is widely used in important departments and public places such as high-rise buildings, subways, power plants, nuclear power plants and tunnels, and is gradually developing towards low-smoke, low-toxicity, low-halogen or non-smoke and non-halogen.

[0003] However, the existing fire-resistant cable is mostly tightly covered and stacked in a multi-layer structure, and the tight structure improves the heat superconductivity between the cable mechanisms to a certain extent, so that the heat is easily accumulated in the internal structure of the cable and the cable is easily damaged due to heat accumulation. Meanwhile, the existing heat-resistant cable has insufficient pressure resistance and bending resistance, and is easily damaged by bending when subjected to external force. Based on this, the application provides a cross-linked polyethylene insulation low-smoke halogen-free flame-retardant fire-resistant power cable. SUMMARY

[0004] The application provides a cross-linked polyethylene insulation low-smoke halogen-free flame-retardant fire-resistant power cable, which solves the problem of tight adhesion between the cable core and the protective layer in the background technology, so that heat is easily accumulated in the cable, the cable is easily damaged due to heat accumulation, and the existing heat-resistant cable has insufficient pressure resistance and bending resistance.

[0005] The application provides the following technical scheme: a cross-linked polyethylene insulation low-smoke halogen-free flame-retardant fire-resistant power cable, which comprises a cable inner core, the cable inner core is a layered structure, the cable inner core comprises a shielding net and a cable conductor arranged in the shielding net, the cable conductor is in a spiral shape, the shielding net comprises uniformly distributed metal rings, and adjacent two metal rings are connected by a metal wire, and the metal wire is in a wave shape; an isolation layer is wound outside the cable inner core, a heat dissipation gap is formed between the isolation layer and the cable inner core, and a cable protective layer is arranged outside the isolation layer.

[0006] Preferably, the isolation layer comprises a belt body, isolation strips are arranged at both ends of the inner side of the belt body, the two isolation strips are arranged in parallel along the length direction of the belt body, and through holes are uniformly arranged on the isolation strips.

[0007] Preferably, the inner side of the belt adopts a non-smooth surface design, and the inner side of the belt is provided with a continuous corrugated texture structure.

[0008] Preferably, the outer side wall of the isolation layer is provided with a connecting layer, and the isolation layer is connected with the cable protection layer through the connecting layer.

[0009] Preferably, metal wires are uniformly distributed between the two adjacent metal rings, and the inner wall of the metal ring is provided with an isolation pad, and the shielding net is in contact with the cable conductor through the isolation pad.

[0010] Preferably, the metal ring comprises two symmetrical half rings, and the flat sections of the two half rings are connected.

[0011] Preferably, the cable protection layer is of a layered structure, and sequentially comprises an insulation shielding layer, a water-blocking layer, a fire-resistant layer and a flame-retardant sheath layer from inside to outside.

[0012] Preferably, the water-blocking layer comprises a limiting sleeve, the limiting sleeve is filled with water-blocking particles, the limiting sleeve is uniformly provided with water-absorbing micropores, and the inner wall of the limiting sleeve is provided with a water-absorbing expansion pad.

[0013] Preferably, the fire-resistant layer is of a hollow structure, and the fire-resistant layer is filled with heat-conducting particles.

[0014] Preferably, the outer surface of the flame-retardant sheath layer is uniformly embedded with reinforcing ribs, the outer surface of the flame-retardant sheath layer is provided with a reflective layer, the flame-retardant sheath layer is of a hollow structure, and the inner cavity of the flame-retardant sheath layer is filled with inorganic metal hydrate.

[0015] Compared with the prior art, the present application has the following beneficial effects:

[0016] 1. The cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable, through the optimization of the cable inner core, the cable inner core can be elastically deformed under the action of bending force, the influence of external force on the cable inner core is reduced, the bending resistance is improved, the cable inner core has high current-carrying performance, and the adaptability of the cable is improved.

[0017] 2. The cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable, through the optimization of the cable protection layer, reinforcing ribs are arranged outside the cable protection layer to improve the bending resistance of the cable protection layer, the water-absorbing expansion pad is used to realize dynamic plugging at the crack of the cable protection layer, the cable protection layer has precise self-repairing and double waterproof mechanism functions, and the water-blocking performance of the cable protection layer is improved.

[0018] 3、The crosslinked polyethylene insulation low-smoke halogen-free flame-retardant fire-resistant power cable, through setting the isolation layer between the cable core and the cable protection layer, heat on the cable core can be quickly discharged, heat accumulation in the cable core is avoided, the probability of cable damage due to heat accumulation is reduced, the service life of the cable is prolonged, and the isolation layer improves the water resistance and flame resistance of the cable. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a front view of the structure of the present application.

[0020] Figure 2 It is a schematic view of the structure of the present application, and the cable core is wrapped with an isolation strip.

[0021] Figure 3 It is a schematic view of the structure of the present application.

[0022] Figure 4 It is a partial view of the structure of the present application.

[0023] Figure 5 It is a structure of the present application Figure 4 a top view schematic view;

[0024] Figure 6 It is a structure of the present application Figure 4 a front view schematic view;

[0025] Figure 7 It is a cross-sectional view of the cable protection layer of the structure of the present application.

[0026] In the figure: 1, cable core; 2, isolation layer; 3, cable protection layer; 4, belt; 5, isolation strip; 6, metal ring; 7, metal wire; 8, isolation pad; 9, cable conductor; 10, semicircular ring; 11, insulation shielding layer; 12, water blocking layer; 13, fire-resistant layer; 14, flame-retardant sheath layer; 15, limiting sleeve; 16, elastic pad; 17, water-absorbing expansion pad; 18, reinforcing rib; 19, connecting layer. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0028] An embodiment of the present application is provided: please refer to Figures 1-7The application discloses a cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable, which comprises a cable inner core 1, the cable inner core 1 is of a layered structure, and the cable inner core 1 comprises a shielding net and a cable conductor 9 arranged in the shielding net. The shielding net can uniformly distribute the electric field of the cable conductor 9, avoid the insulation layer of the cable conductor 9 from being punctured, reduce dielectric loss, reduce the operation temperature of the cable, and can absorb external high-frequency electromagnetic interference and inhibit the influence of electromagnetic interference on the cable conductor 9, thereby facilitating the use of the cable.

[0029] The shielding net comprises uniformly distributed metal rings 6, and adjacent two metal rings 6 are connected through metal wires 7; the metal wires 7 are in a wave shape, and the metal wires 7 are uniformly distributed between the adjacent two metal rings 6. Through the arrangement of the shielding net structure, the metal rings can provide rigid support for the cable during use, reduce the risk of deformation of the shielding net when the cable is bent, and when the cable is bent, the metal wires 7 can improve the bending resistance of the cable, so that the cable can have a longer service life and better reliability in application scenarios that need to be frequently bent or wound.

[0030] The material of the shielding net can be selected according to requirements, which is not limited herein. In an embodiment of the application, the material of the shielding net is metal copper, which facilitates heat dissipation of the cable inner core 1.

[0031] The inner wall of the metal ring 6 is provided with a separation pad 8, and the shielding net is in contact with the cable conductor 9 through the separation pad 8. Through the arrangement of the separation pad 8, interference fit can be realized between the metal ring 6 and the cable conductor 9, the shielding stability of the shielding net is improved, and the rebound force of the separation pad 8 can reduce the extrusion of the metal ring 6 on the cable conductor 9 when the metal ring 6 expands, so as to avoid damage to the insulation layer of the cable conductor 9 due to the extrusion and deformation of the conductor, thereby facilitating the use of the cable. The thickness and material of the separation pad 8 can be selected according to requirements, which is not limited herein. In an embodiment of the application, the material of the separation pad 8 is heat-conducting silica gel, which can realize mechanical buffering and facilitate heat dissipation of the cable conductor 9.

[0032] The metal ring 6 comprises two symmetrical half circular rings 10, and the flat sections of the two half circular rings 10 are connected, that is, the shielding net is composed of two half pipe nets, each half pipe net of the shielding net is provided with a plurality of half circular rings 10 at equal intervals, and adjacent two half circular rings 10 are connected through the metal wires 7, so that the cable conductor 9 can be placed into one half pipe net of the shielding net during production, and the other half pipe net is combined, and the two plates are connected through welding or other conventional ways. When the two half pipe nets are connected through welding, pulse laser sealing welding technology can be used to improve the butt joint precision of the flat sections of the two half circular rings 10.

[0033] The cable conductor 9 is in a spiral shape, and through the arrangement of the spiral cable conductor 9, when the cable is bent, the cable conductor 9 can be elastically deformed under the action of external force, reducing the influence of external force on the cable, thereby improving the tensile and torsional resistance of the cable, reducing the risk of cable breakage, increasing the surface area of the cable conductor, improving the current carrying capacity of the cable, and improving the adaptability of the cable.

[0034] As described above, when the cable is used, the cable core 1 can be elastically deformed under the action of bending force through the optimization of the cable core 1, reducing the influence of external force on the cable core 1, thereby improving the bending resistance and enabling the cable core 1 to have high current carrying capacity, thereby improving the adaptability of the cable.

[0035] The cable core 1 is wrapped with an isolation layer 2, and a heat dissipation gap is formed between the isolation layer 2 and the cable core 1. Through the arrangement of the heat dissipation gap, the heat dissipation speed of the cable core 1 can be improved, the risk of heat accumulation of the cable core 1 can be reduced, thereby alleviating the insulation aging of the cable core, prolonging the service life of the cable, and the air in the heat dissipation gap can delay the spread of flames, so that the cable can prolong the power supply time in a fire and improve the reliability of the cable.

[0036] In the production of the cable, the isolation layer 2 can be wrapped around the cable core 1 in a wrapping manner. When the isolation layer 2 is connected to the cable core 1 in this way, the isolation layer 2 includes a belt body 4, both ends of the inner side of the belt body 4 are provided with isolation strips 5, the two isolation strips 5 are arranged in parallel along the length direction of the belt body 4, and the isolation strips 5 are uniformly provided with through holes. When the belt body 4 is wrapped, the isolation strips 5 are wound around the outer surface of the cable core 1, at this time, a heat dissipation gap is formed between the two isolation strips 5, and under the action of the through holes, heat convection can occur in the heat dissipation gap, so that the heat in the high temperature area of the cable can be quickly dispersed to the low temperature area of the cable, improving the heat dissipation efficiency of the cable.

[0037] In addition, the inner side of the belt body 4 is designed as a non-smooth surface, and the inner side of the belt body 4 is provided with a continuous corrugated texture structure. Through the periodic concave-convex design of the belt body 4, the contact area of the belt body 4 and the air in the heat dissipation gap can be improved, the heat conduction speed of the belt body 4 can be improved, the laminar flow can be easily destroyed, the air flow speed in the heat dissipation gap can be improved, and the heat dissipation efficiency of the isolation layer 2 can be improved.

[0038] The material of the isolation layer 2 can be selected according to requirements, which is not limited herein. In an embodiment of the present application, the material of the isolation layer 2 is copper.

[0039] The outer part of the isolation layer 2 is covered by the cable protection layer 3, and the outer side wall of the isolation layer 2 is provided with a connecting layer 19, and the isolation layer 2 is connected with the cable protection layer 3 through the connecting layer 19. Through the setting of the connecting layer 19, the small gap that may exist at the overlapping part or the joint of the belt 4 can be compensated, so that the isolation layer 2 can form a sealed structure, and the isolation layer 2 can simultaneously have a water blocking function. The material of the connecting layer 19 can be selected according to the requirements, which is not limited here. In an embodiment of the present application, the material of the connecting layer 19 is a heat-conducting silica gel with flame retardance, so that the isolation layer 2 has a flame retardant function.

[0040] As can be known from the above description, when the cable is used, the cable inner core 1 and the cable protection layer 3 have a heat dissipation gap, so that the heat on the cable inner core 1 can be quickly discharged, avoiding the accumulation of heat in the cable inner core 1, reducing the probability of damage of the cable due to heat accumulation, prolonging the service life of the cable, and improving the water blocking and flame retardant performance of the cable by the isolation layer 2.

[0041] The cable protection layer 3 has a layered structure, and from the inside to the outside, it includes an insulating shielding layer 11, a water blocking layer 12, a fire resistant layer 13, and a flame retardant sheath layer 14.

[0042] Through the setting of the insulating shielding layer 11, the electric field can be uniform, the electric field distortion caused by the burr on the surface of the cable conductor 9 can be eliminated, partial discharge can be avoided, and the accumulation of electric charge at the interface can be reduced. In order to improve the heat conduction effect of the insulating shielding layer 11, the insulating shielding layer 11 can be embedded with insulating heat-conducting particles. The insulating heat-conducting particles can be used to speed up the heat conduction speed of the insulating shielding layer 11. The materials of the insulating shielding layer 11 and the insulating heat-conducting particles can be selected according to the requirements, which is not limited here. In an embodiment of the present application, the material of the insulating shielding layer 11 can be cross-linked polyethylene, and the material of the insulating heat-conducting particles can be modified graphene oxide.

[0043] The water blocking layer 12 is used to prevent water from penetrating along the longitudinal direction of the cable and to protect the cable inner core 1. In an embodiment of the present application, the water blocking layer 12 includes a limiting sleeve 15, which has a hollow structure and is filled with water blocking particles. The limiting sleeve 15 is uniformly provided with water absorption micropores, and the inner wall of the limiting sleeve 15 is provided with a water absorption expansion pad 17. Through the setting of the water blocking layer 12, the water on the outer side of the water blocking layer 12 can be adsorbed by the water absorption expansion pad 17 and the water blocking particles through the water absorption micropores. The expansion of the water absorption expansion pad 17 can block the water absorption micropores at the water penetration position or the damaged holes on the water blocking layer 12, preventing the water from continuing to spread and improving the water blocking reliability of the water blocking layer 12. In this process, the limiting sleeve 15 limits the expansion of the water absorption expansion pad 17 and the water blocking particles, limits the expansion amount of the water absorption expansion pad 17 and the water blocking particles, avoids the extrusion of the water blocking particles on the isolation layer 2 and the cable inner core 1 due to over-expansion, and facilitates the use of the cable.

[0044] In addition, the water-absorbing expansion pad 17 is uniformly provided with an elastic pad 16 close to one side of the water-blocking particles. The elastic pad 16 can be used to limit the water-blocking particles, so that the position of the water-blocking particles in the inner cavity of the water-blocking layer 12 is stable. The elastic force of the elastic pad 16 can reserve space for the expansion of both the water-blocking particles and the water-absorbing expansion pad 17, facilitating the expansion of the water-blocking particles and the water-absorbing expansion pad 17. The materials of the water-absorbing expansion pad 17 and the water-blocking particles can be selected according to requirements, which are not limited herein. In an embodiment of the present application, the materials of the water-absorbing expansion pad 17 and the water-blocking particles are both water-absorbing resin. The material of the limiting sleeve 15 can be copper, and the material of the elastic pad 16 is heat-conducting silica gel.

[0045] The water-absorbing micropores allow a small amount of water vapor to penetrate, but block liquid water, avoiding the accumulation of condensed water caused by temperature difference. The water-absorbing micropores form micro-airflow channels, facilitating heat conduction. The size of the water-absorbing micropores can be set according to requirements, which are not limited herein.

[0046] The fire-resistant layer 13 is used to delay the transmission of high temperature to the inside of the cable and maintain the insulation integrity in the flame. The fire-resistant layer 13 of the present application is a hollow structure, and the inner cavity of the fire-resistant layer 13 is filled with heat-conducting particles. The heat-conducting particles can make the fire-resistant layer 13 have both heat dissipation and fire-resistant integrity. The material of the heat-conducting particles can be selected according to requirements, which are not limited herein. The material of the fire-resistant layer 13 can be mica tape, and the material of the heat-conducting particles can be boron nitride.

[0047] The flame-retardant sheath layer 14 is used for flame retardation and combustion suppression. The material of the flame-retardant sheath layer 14 can be low-smoke halogen-free flame-retardant polyolefin. The outer surface of the flame-retardant sheath layer 14 in the present application is uniformly embedded with reinforcing ribs 18, which can improve the bending resistance of the flame-retardant sheath layer 14. The outer surface of the flame-retardant sheath layer 14 is provided with a reflective layer, which can reflect heat and reduce the influence of external heat on the cable. The flame-retardant sheath layer 14 is a hollow structure, and the inner cavity of the flame-retardant sheath layer 14 is filled with inorganic metal hydrate. The inorganic metal hydrate can decompose and absorb a large amount of heat in a high-temperature environment, thereby reducing the temperature of the flame-retardant sheath layer 14 and delaying combustion, significantly improving the waterproof safety and comprehensive performance of the cable. The materials of the reinforcing ribs 18 and the inorganic metal hydrate can be selected according to requirements, which are not limited herein. In an embodiment of the present application, the material of the inorganic metal hydrate is aluminum hydroxide.

[0048] In summary: the crosslinked polyethylene insulation low-smoke halogen-free flame-retardant fire-resistant power cable, by optimizing the cable core 1, the cable core 1 can be elastically deformed under the action of bending force, reduce the influence of external force on the cable core 1, thereby improving the bending resistance, and the cable core 1 has the performance of high current, improve the adaptability of the cable. Through the optimization of the cable protection layer 3, the reinforcing rib 18 is arranged outside the cable protection layer 3, the bending resistance of the cable protection layer 3 is improved, the water absorption expansion pad 17 is used to realize the dynamic sealing of the crack of the cable protection layer 3, so that the cable protection layer 3 has the functions of precise self-repairing and double waterproof mechanism, and the water resistance of the cable protection layer 3 is improved. By setting the isolation layer 2 between the cable core 1 and the cable protection layer 3, the heat on the cable core 1 can be quickly discharged, avoiding the accumulation of heat in the cable core 1, reducing the probability of damage of the cable due to heat accumulation, prolonging the service life of the cable, and the isolation layer 2 improves the water resistance and flame resistance of the cable.

[0049] The standard parts used in the application can be purchased from the market, the special-shaped parts can be ordered according to the description and the drawings, the specific connection mode of each structure adopts the conventional technical means such as bolt connection in the prior art, the mechanical, part and equipment adopt the conventional type in the prior art, the material of each component of the application can be selected according to the requirement, which will not be described in detail, the contents not described in detail in the specification belong to the prior art known by the person skilled in the art, although the embodiments of the application have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to the embodiments without departing from the principles and spirits of the application, the scope of the application is defined by the appended claims and their equivalents.

Claims

1. A cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable, comprising a cable core (1), characterized in that: The cable core (1) has a layered structure. The cable core (1) includes a shielding mesh and a cable conductor (9) disposed within the shielding mesh. The cable conductor (9) is spiral-shaped. The shielding mesh includes uniformly distributed metal rings (6). Two adjacent metal rings (6) are connected by metal wires (7). The metal wires (7) are wavy. An isolation layer (2) is wound around the outside of the cable core (1). A heat dissipation gap is formed between the isolation layer (2) and the cable core (1). The outside of the isolation layer (2) is covered with a cable protection layer (3).

2. The cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable according to claim 1, characterized in that: The isolation layer (2) includes a belt (4), and isolation strips (5) are provided at both ends of the inner side of the belt (4). The two isolation strips (5) are arranged parallel to each other along the length of the belt (4), and through holes are evenly provided on the isolation strips (5).

3. The cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable according to claim 2, characterized in that: The inner side of the belt (4) is designed with a non-smooth surface and has a continuous wavy texture structure.

4. The cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable according to claim 1, characterized in that: The outer wall of the isolation layer (2) is provided with a connecting layer (19), and the isolation layer (2) is connected to the cable protection layer (3) through the connecting layer (19).

5. The cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable according to claim 1, characterized in that: Metal wires (7) are evenly distributed between two adjacent metal rings (6), and an isolation pad (8) is provided on the inner wall of the metal ring (6). The shielding mesh contacts the cable conductor (9) through the isolation pad (8).

6. The cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable according to claim 5, characterized in that: The metal ring (6) includes two symmetrical semicircular rings (10), and the straight sections of the two semicircular rings (10) are connected.

7. The cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable according to claim 1, characterized in that: The cable protection layer (3) has a layered structure, which includes an insulating shielding layer (11), a water-blocking layer (12), a fire-resistant layer (13), and a flame-retardant sheath layer (14) from the inside to the outside.

8. The cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable according to claim 7, characterized in that: The water-blocking layer (12) includes a limiting sleeve (15), which is filled with water-blocking particles. Water-absorbing micropores are uniformly arranged on the limiting sleeve (15), and a water-absorbing expansion pad (17) is provided on the inner wall of the limiting sleeve (15).

9. A cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable according to claim 7, characterized in that: The refractory layer (13) is a hollow structure, and the refractory layer (13) is filled with thermally conductive particles.

10. A cross-linked polyethylene insulated low-smoke halogen-free flame-retardant fire-resistant power cable according to claim 7, characterized in that: The outer surface of the flame-retardant sheath layer (14) is uniformly inlaid with reinforcing ribs (18), the outer surface of the flame-retardant sheath layer (14) is provided with a reflective layer, the flame-retardant sheath layer (14) is a hollow structure, and the inner cavity of the flame-retardant sheath layer (14) is filled with inorganic metal hydrates.

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