Crosslinked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable

Abstract

The application discloses a kind of crosslinking polyolefin insulation low-smoke halogen-free flame-retardant fire-resistant cable, including the reinforcing core in center, the reinforcing core outer circumference is arranged with multiple copper conductors, the outside of copper conductor is covered with protective layer, the outside of all copper conductors is covered with insulating layer, shielding layer, heat insulation layer and outer sheath in turn, the gap between the inside of insulating layer and each copper conductor and the gap between reinforcing core and each copper conductor are provided with filling, multiple locating racks are arranged in the filling, each copper conductor is clamped in the fork-shaped piece arranged on locating rack, buffer assembly is arranged on locating rack.The application can strengthen the positioning of each conductor in the cable by setting locating rack, prevent each conductor from slipping or twisting, in addition, the setting of fork-shaped piece is convenient to cooperate with multiple conductors, and the production and assembly of cable will not become difficult, and the impact resistance of cable is strengthened by buffer assembly.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a cross-linked polyolefin insulated low-smoke halogen-free flame-retardant and fire-resistant cable. Background Technology

[0002] The basic structure of a cable consists of four parts: the conductor, the insulation layer, the shielding layer, and the protective layer. The conductor is responsible for transmitting current or electrical signals and is the carrier of electrical energy and signals. The insulation layer wraps around the conductor to prevent current leakage, ensure electrical isolation between different conductors and between the conductor and the outside world, and ensure safe operation. The shielding layer is mainly used to resist external electromagnetic interference and prevent internal signals from interfering with the outside world, ensuring the stability of signal transmission. The protective layer is the outermost protective structure of the cable, which can resist the effects of mechanical damage, chemical corrosion, moisture, ultraviolet rays and other environmental factors, extending the service life of the cable. Existing cables can basically meet the needs of daily use, but there are still some shortcomings that need to be improved.

[0003] Patent document 202010886343.8 discloses a cross-linked polyethylene insulated low-smoke halogen-free fire-resistant power cable, including a main cable. The main cable includes an outer sheath, with steel tape armoring on the inner periphery of the outer sheath. An inner sheath is located near the center of the steel tape armoring, with wrapping tape on the inner periphery of the inner sheath. PVC filler is placed in the center of the wrapping tape, and three sets of guide bodies are evenly arranged on the inner side of the PVC filler. This invention improves the overall strength and toughness of the main cable, preventing damage from external forces, protecting the internal structure of the main cable, ensuring its normal use, effectively preventing the steel tape armoring from sliding inside the outer sheath, preventing slippage during cable pulling, and preventing cable slippage during internal disassembly. It also provides insulation and moisture protection for the internal conductors, preventing localized damage to the copper conductors that could affect normal use.

[0004] In the prior art, as described in the aforementioned patent, adding a separator structure to the cable can ensure that each conductor is independently isolated from each other, and improve anti-slip performance and overall cable strength. However, the existing separator structure is placed between each conductor. When the cable is subjected to external heavy objects or falls, the outer protection strength of the conductor is insufficient. Therefore, there is an urgent need for a cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable to overcome the above-mentioned shortcomings in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable includes a central reinforcing core, with multiple copper conductors arranged around the outer circumference of the reinforcing core. The outer sides of the copper conductors are covered with a protective layer. The outer sides of all copper conductors are sequentially covered with an insulation layer, a shielding layer, a heat insulation layer, and an outer sheath. The gaps between the insulation layer and each copper conductor, as well as the gaps between the reinforcing core and each copper conductor, are filled. Multiple positioning frames are spaced apart within the filling. The reinforcing core passes through the center of the positioning frame, and each copper conductor is embedded in a fork-shaped component on the positioning frame. A buffer assembly is provided on the positioning frame.

[0007] Preferably, the protective layer is made of mica tape.

[0008] Preferably, the insulating layer is made of cross-linked polyolefin.

[0009] Preferably, the material of the shielding layer is aluminum.

[0010] Preferably, the material of the heat insulation layer is a ceramicized polymer composite material.

[0011] Preferably, the outer sheath is made of low-smoke halogen-free polyolefin.

[0012] Preferably, the buffer assembly includes a support body disposed between two adjacent fork-shaped members. The support body supports the inner wall of the insulating layer. Two telescopic members are symmetrically disposed on the support body. One end of the telescopic member extends movably out of the support body and is hinged to one end of the nearby fork-shaped member. The ends of the fork-shaped members can be elastically bent.

[0013] Preferably, a marking line is provided on the outer side of the outer sheath along the length of the cable. When the cable is installed, the marking line faces upward, and a gas generating component is provided on the support body corresponding to the marking line. The gas generating component is triggered when the support body is compressed.

[0014] Preferably, the gas generating assembly includes a liquid cavity disposed within a support body, a reaction chamber disposed within a heat insulation layer, an interface on the support body for connecting the liquid cavity and the reaction chamber, and a partition component disposed within the interface. The partition component cancels the partition of the interface after the support body is pressed and moved to the position closest to the center of the cable.

[0015] Preferably, the partition assembly includes a partition body movably mounted on a support body, with sliding members at both ends of the partition body, a buffer cavity matching the sliding members inside the telescopic member, and a vulnerable section in the middle of the partition body that blocks the interaction opening.

[0016] In the above technical solution, the beneficial effects of the present invention are: This cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable features a positioning frame that strengthens the positioning of each conductor within the cable in sections, preventing slippage or twisting. Furthermore, the fork-shaped components facilitate compatibility with multiple conductors, minimizing difficulties in cable production and assembly. Additionally, the buffer components enhance the cable's impact resistance, ensuring safe operation in harsh environments and extending its service life.

[0017] It should be understood that the foregoing general description and the following detailed description are exemplary and illustrative only, and are not intended to limit this disclosure.

[0018] This application provides an overview of various implementations or examples of the technology described in this disclosure, and is not a full disclosure of the entire scope or all features of the disclosed technology. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0020] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a frontal cross-sectional view of the present invention. Figure 3 This is a front cross-sectional view of the positioning frame structure when the cable is not under pressure according to the present invention; Figure 4 For the present invention Figure 3 Enlarged structural diagram at point A; Figure 5 This is a front cross-sectional view of the positioning frame structure when the cable is under downward pressure according to the present invention; Figure 6 For the present invention Figure 5 Enlarged structural diagram at point B; Figure 7 This is a side cross-sectional view of the present invention. Figure 8 This is a schematic diagram of the positioning frame structure of the present invention.

[0021] Explanation of reference numerals in the attached figures: 1. Reinforcing core; 2. Copper conductor; 3. Protective layer; 4. Insulation layer; 5. Shielding layer; 6. Heat insulation layer; 7. Outer sheath; 8. Filler; 9. Positioning frame; 10. Fork-shaped component; 11. Support body; 12. Telescopic component; 13. Liquid chamber; 14. Reaction chamber; 15. Interchange port; 16. Partition body; 17. Sliding component; 18. Buffer chamber; 19. Piston; 20. Push rod; 21. Elastic component. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0023] Please see Figure 1-8 The present invention provides a cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable, comprising a reinforcing core 1 located at the center, multiple copper conductors 2 arranged around the outer circumference of the reinforcing core 1, a protective layer 3 covering the outer side of each copper conductor 2, and an insulation layer 4, a shielding layer 5, a heat insulation layer 6, and an outer sheath 7 sequentially covering the outer side of each copper conductor 2. The gaps between the insulation layer 4 and each copper conductor 2, as well as the gaps between the reinforcing core 1 and each copper conductor 2, are filled with fillers 8. Multiple positioning frames 9 are spaced apart within the fillers 8. The reinforcing core 1 passes through the center of the positioning frame 9, and each copper conductor 2 is embedded in a fork-shaped piece 10 provided on the positioning frame 9. A buffer assembly is provided on the positioning frame 9.

[0024] Specifically, the reinforcing core 1 is located at the center of the cable, and its main function is to improve the cable's mechanical strength and tensile and bending resistance. The preferred material is aramid fiber or galvanized steel wire, which combines lightweight, high strength, and heat resistance. The copper conductor 2 is preferably multi-strand oxygen-free copper stranded together, with an oxygen content of <0.001%, to prevent cuprous oxide embrittlement at high temperatures and ensure high conductivity and structural integrity even in flames below 1000℃, providing a stable current path for emergency power supply. The protective layer 3 is made of mica tape, which transforms into a dense ceramic layer under flame conditions, providing fire resistance, heat insulation, and a certain mechanical strength to protect the copper conductor 2. The insulation layer 4 is made of cross-linked polyolefin, which produces extremely low smoke during combustion and does not generate toxic hydrogen halide gas, exhibiting excellent performance. Insulation and water resistance; the shielding layer 5 is made of aluminum, which is pressure-resistant, impact-resistant, and prevents external damage. It can also provide electromagnetic shielding, suppress external interference and signal leakage, and serve as a grounding conductor (PE) wire to improve electrical safety. Aluminum is lightweight and has moderate thermal conductivity, which helps to distribute heat evenly and avoid local overheating. The insulation layer 6 is made of ceramicized polymer composite material, preferably ceramicized silicone rubber or ceramicized polyolefin, which is sintered into a ceramic shell at high temperatures to effectively block flames, heat and smoke. The outer sheath 7 is made of low-smoke halogen-free polyolefin. The filler 8 is made of inorganic flame-retardant powder, which is used to help fix the conductor position, block the lateral spread path of flames in the conductor gap, and at the same time give the cable appropriate bending flexibility. The positioning frame 9 is located within the insulation layer 4 and is used to position the reinforcing core 1 and the relative positions of each copper conductor 2. The inner wall of the fork-shaped member 10 is roughened and in close contact with the outside of the copper conductor 2 inside it to prevent the copper conductor 2 from slipping. The fork-shaped member 10 is preferably U-shaped with the opening facing outward. The buffer assembly buffers external pressure and, together with the positioning frame 9, keeps each copper conductor 2 in its original shape, maintaining circuit performance. In practical use, this technical solution, by setting the positioning frame 9, can strengthen the positioning of each conductor inside the cable in sections, preventing the conductors from slipping or twisting. In addition, the setting of the fork-shaped member 10 facilitates cooperation with multiple conductors, does not make the cable production and assembly difficult, and the buffer assembly enhances the cable's impact resistance, ensuring the cable's safe use in harsh environments and extending the cable's service life.

[0025] Compared with the prior art, the cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable proposed in this embodiment of the invention can strengthen the positioning of each conductor in the cable in sections by setting the positioning frame 9, so as to prevent the conductors from slipping or twisting. In addition, the setting of the fork-shaped part 10 facilitates the cooperation with multiple conductors and does not make the production and assembly of the cable difficult. Furthermore, the shock resistance of the cable is enhanced by the buffer component, ensuring the safety of the cable in harsh environments and extending the service life of the cable.

[0026] In environments such as high-rise buildings, cables are laid in cable tracks. When a fire occurs, burning materials from the upper floors of the building may fall and hit the cables. This impacts the cables while the burning materials continue to burn on top of them, causing heat to be transferred to the cables more quickly. This significantly affects the self-protection period of fire-resistant cables in a fire. The following embodiments are proposed to address this issue.

[0027] In another embodiment of the present invention, the buffer assembly includes a support body 11 disposed between two adjacent fork-shaped members 10. The support body 11 supports the inner wall of the insulating layer 4. Two telescopic members 12 are symmetrically disposed on the support body 11. One end of the telescopic member 12 extends movably out of the support body 11 and is hinged to one end of the nearby fork-shaped member 10. The ends of the fork-shaped members 10 are elastically bendable. Specifically, an isolation layer is fitted to the end face of the positioning frame 9. The isolation layer is used to prevent the filler 8 from entering the space between the two adjacent fork-shaped members 10, thereby satisfying the requirement that the support body 11 can be flexible. The insulation layer is soft and deformable under pressure. The support 11 is fan-shaped and matches the inner wall of the insulation layer 4. The support 11 can move closer to or away from the center of the positioning frame 9. The telescopic members 12 are arc-shaped, and the arc centers of the two telescopic members 12 are concentric with the fan-shaped center of the support 11. The ends of the fork-shaped members 10 are T-shaped. The elastic bending function of the ends of the fork-shaped members 10 allows them to further cover the outside of the conductor, thereby improving protection. In the unbent state, the opening of the fork-shaped members 10 is the largest, which facilitates cable production. In actual use, when the cable is subjected to external pressure, the support 11 moves closer to the center of the positioning frame 9, and then the ends of the fork-shaped members 10 are bent by the telescopic members 12 on both sides. At the same time, the telescopic members 12 extend to compensate for the displacement of the bending ends of the fork-shaped members 10. Thus, the elastic deformation of the fork-shaped members 10 buffers the external pressure on the cable. In addition, the bending of the fork-shaped members 10 further covers the outside of the conductor, thereby improving protection.

[0028] In another embodiment of the present invention, a marking line is provided on the outer side of the outer sheath 7 along the length of the cable. When the cable is installed, the marking line faces upward, and a gas generating component is provided on the support 11 corresponding to the marking line. The gas generating component is triggered when the support 11 is subjected to pressure. Specifically, by setting the marking line, it is convenient to lay the cable with the marking line facing upward, thereby ensuring the effective use of the gas generating component. When the marking line is facing upward, one of the support 11 faces upward and corresponds directly to the marking line. The gas generating component is used to generate flame-retardant gases such as nitrogen after the support 11 is subjected to a certain pressure, which helps to insulate heat, retard flames, and extinguish fires appropriately.

[0029] As a preferred embodiment, the gas generating assembly includes a liquid chamber 13 disposed within a support body 11, a reaction chamber 14 disposed within a heat insulation layer 6, and an interface 15 on the support body 11 for connecting the liquid chamber 13 and the reaction chamber 14. An isolation component is disposed within the interface 15. The isolation component cancels the isolation of the interface 15 after the support body 11 is pressed and moved to the position closest to the cable center. Specifically, the liquid chamber 13 is filled with a reaction liquid, preferably an ammonium salt solution, and the reaction chamber 14 is filled with a reactant, preferably sodium nitrite. The reaction liquid and reactant mix and react to generate a flame-retardant gas, such as nitrogen. The interface 15 extends upwards through the support body 11. The isolation component completely isolates the reaction liquid from the reactant. The isolation component is triggered after the support body 11 is pressed and moved to the position closest to the cable center, thus preventing accidental triggering during cable laying or other non-fire situations.

[0030] As a preferred technical solution of this embodiment, the partition assembly includes a partition body 16 movably disposed on the support body 11. Sliding members 17 are respectively disposed at both ends of the partition body 16. A buffer cavity 18 matching the sliding member 17 is disposed in the telescopic member 12. The middle part of the partition body 16 is set as a vulnerable part and blocks the interaction port 15. Specifically, the partition body 16 is sheet-shaped and passes through the interaction port 15 in a direction perpendicular to the axial direction of the interaction port 15. The sliding member 17 only moves within the buffer cavity 18. The vulnerable part is easy to break in the length direction of the partition body 16, but not easy to break in the normal direction of the partition body 16. In the initial state, the vulnerable part in the middle of the partition body 16 corresponds to the center of the interaction port 15, and the sliding members 17 at both ends of the partition body 16 are located in the buffer cavity 18 at the end close to the interaction port 15.

[0031] As a further preferred technical solution of this embodiment, a piston 19 is movably disposed in the liquid cavity 13. A stop rod 20 is disposed at the end of the piston 19 away from the interaction port 15. An elastic member 21 is disposed between the two fork-shaped members 10. The end of the stop rod 20 away from the interaction port 15 movably passes through the support body 11 and abuts against the elastic member 21. Specifically, the reaction liquid is located above the piston 19 in the liquid cavity 13. The elastic member 21 is preferably a spring or an elastic band. When the elastic member 21 is a spring, a protrusion is disposed on the surface between the two fork-shaped members 10. The two ends of the spring are limited to the lower side of the protrusion. When the spring is under pressure, it undergoes elastic bending and slides downward in an approximate V-shape. When the elastic member 21 is an elastic band, the two ends of the elastic band are connected to the two protrusions. When the elastic member 21 is under pressure, it undergoes elastic deformation, causing the middle to stretch downward in an approximate V-shape. When the elastic member 21 is not affected by external force, it remains straight, thereby supporting the stop rod 20. Furthermore, an annular air cavity is provided inside the heat insulation layer 6, which is located close to the outer sheath 7 and is connected to the reaction chamber 14.

[0032] In practical use, after the cable is correctly laid with the marked lines facing upwards, when a fire occurs and burning materials fall and hit the cable, the upper support 11 moves downwards under pressure. The telescopic members 12 on both sides compress the fork-shaped member 10, causing elastic deformation to achieve buffering. At this time, the partition 16 remains in place to block the interface 15, and the reaction liquid in the liquid chamber 13 is difficult to compress. Therefore, the support 11 drives the piston 19 and the push rod 20 to descend, compressing the elastic member 21. The elastic member 21 deforms and stores elastic potential energy. When the support 11 descends to its closest position to the center of the cable, the sliding member 17 moves within the buffer chamber 18 to one end close to the interface 15. Then, the telescopic members 12 pull the partition 16 along its length, causing... When the weak part in the middle of the partition 16 is broken, the interface 15 opens, the elastic potential energy of the elastic element 21 is released, and the push rod 20 and piston 19 are pushed. The piston 19 squeezes the reaction liquid in the liquid chamber 13 upward and enters the reaction chamber 14 through the interface 15. The reaction liquid mixes with the reactants in the reaction chamber 14 to produce a chemical reaction and continuously generate flame-retardant gas. On the one hand, the flame-retardant gas enters the gas cavity in the heat insulation layer 6, and as the heat insulation layer 6 is heated and ceramicized, uniform pores are formed on the heat insulation layer 6, which enhances the heat insulation effect. On the other hand, when the outer sheath 7 is burned and cracked, the excess flame-retardant gas is released, which can extinguish the burning materials on the cable to a certain extent, thereby ensuring the effectiveness of the cable's self-protection period.

[0033] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable, comprising a reinforcing core (1) located at the center, a plurality of copper conductors (2) arranged around the outer circumference of the reinforcing core (1), a protective layer (3) covering the outer side of each copper conductor (2), and an insulation layer (4), a shielding layer (5), a heat insulation layer (6), and an outer sheath (7) sequentially covering the outer side of each copper conductor (2), wherein the gaps between the insulation layer (4) and each copper conductor (2) and the gaps between the reinforcing core (1) and each copper conductor (2) are filled (8), characterized in that, Multiple positioning frames (9) are spaced apart inside the filling (8). The reinforcing core (1) passes through the center of the positioning frame (9). Each copper conductor (2) is embedded in the fork-shaped piece (10) set on the positioning frame (9). A buffer component is set on the positioning frame (9).

2. The cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable according to claim 1, characterized in that, The protective layer (3) is made of mica tape.

3. The cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable according to claim 1, characterized in that, The insulating layer (4) is made of cross-linked polyolefin.

4. The cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable according to claim 1, characterized in that, The material of the shielding layer (5) is aluminum.

5. The cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable according to claim 1, characterized in that, The material of the heat insulation layer (6) is a ceramicized polymer composite material.

6. The cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable according to claim 1, characterized in that, The outer sheath (7) is made of low-smoke halogen-free polyolefin.

7. The cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable according to claim 1, characterized in that, The buffer assembly includes a support (11) disposed between two adjacent fork-shaped members (10). The support (11) supports the inner wall of the insulating layer (4). Two telescopic members (12) are symmetrically disposed on the support (11). One end of the telescopic member (12) extends out of the support (11) and is hinged to one end of the fork-shaped member (10) on the near side. The end of the fork-shaped member (10) can be elastically bent.

8. The cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable according to claim 7, characterized in that, The outer sheath (7) has a marking line along the length of the cable. When the cable is installed, the marking line faces upward. A gas generating component is provided on the support (11) corresponding to the marking line. The gas generating component is triggered when the support (11) is pressed.

9. The cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable according to claim 8, characterized in that, The gas generating assembly includes a liquid chamber (13) disposed within a support body (11), a reaction chamber (14) disposed within a heat insulation layer (6), an interface (15) disposed on the support body (11) for connecting the liquid chamber (13) and the reaction chamber (14), an isolation component disposed within the interface (15), and the isolation component cancels the isolation of the interface (15) after the support body (11) is pressed and moved to the position closest to the center of the cable.

10. The cross-linked polyolefin insulated low-smoke halogen-free flame-retardant fire-resistant cable according to claim 9, characterized in that, The partition assembly includes a partition body (16) movably mounted on a support body (11), with sliding members (17) at both ends of the partition body (16), a buffer cavity (18) matching the sliding member (17) inside the telescopic member (12), and a vulnerable part in the middle of the partition body (16) blocking the interaction port (15).

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