Composite flame-retardant control cable

Abstract

This utility model discloses a composite flame-retardant control cable, comprising a conductor core, a double-layer co-extruded insulation layer, a flame-retardant shielding structure layer, and a flame-retardant sheath. The double-layer co-extruded insulation layer, the flame-retardant shielding structure layer, and the flame-retardant sheath are sequentially wrapped around the conductor core from the inside out and are uniformly arranged coaxially. The flame-retardant shielding structure layer includes a wrapped magnetic shielding layer and an electromagnetic shielding braided layer. The wrapped magnetic shielding layer covers the outside of the double-layer co-extruded insulation layer, and the electromagnetic shielding braided layer covers the outside of the wrapped magnetic shielding layer. Several grounding leads extending along the axial direction of the conductor core are arranged between the wrapped magnetic shielding layer and the electromagnetic shielding braided layer. By adopting a composite structure of a wrapped magnetic shielding layer, an electromagnetic shielding braided layer, and embedded grounding leads in the flame-retardant shielding structure layer, the anti-interference capability and charge release efficiency are improved. It can operate stably in scenarios with high requirements for flame retardancy, anti-interference, heat dissipation, and structural stability, ensuring reliable transmission of control signals or electrical energy.

Description

Technical Field

[0001] This utility model relates to the field of cables, and more specifically, to a composite flame-retardant control cable. Background Technology

[0002] A cable is a transmission component that can transmit signals or electrical energy, typically composed of one or more conductors. Cables are classified into DC cables and AC cables based on their environment and application. DC cables are generally used indoors, while AC cables are mostly used outdoors. With continuous technological advancements, different materials can be applied to the cable sheath, allowing for a wider range of applications across various industries. However, traditional cables often have unsatisfactory flame-retardant properties. Due to the materials and design of the cables, they are often unable to effectively prevent the spread of fire in the event of a fire, and may even become the source of the fire themselves. This is particularly common in industrial and construction fields, where high flame-retardant performance requirements for cables are necessary. This application (CN202323397645.7) discloses a flame-retardant composite cable, comprising an outer sheath, which, from the inside out, consists of an inner shielding layer, a heat dissipation layer, and a flame-retardant outer layer. The inner surface of the outer sheath has several grooves arranged at equal intervals. A barrier ring is longitudinally arranged inside the outer sheath, and three mounting rings are longitudinally arranged on the barrier ring, with the mounting rings being hollow. A battery core is longitudinally inserted inside the mounting rings, and its outer surface is sequentially wrapped with an inner sheath and a high-temperature resistant layer. Compared to existing technologies, this application includes a flame-retardant outer layer and barrier rings. The flame-retardant outer layer is made of flame-retardant polyvinyl chloride, possessing excellent flame-retardant and heat-resistant properties. In the event of a fire or high temperature, it can slow the spread of fire, reduce the rate of flame propagation, and improve the safety of the battery core. Combined with the barrier rings, it achieves excellent flame-retardant performance.

[0003] However, the above solutions still have certain drawbacks. Although the above solutions can achieve a certain flame retardant effect by means of outer sheath and radial barrier structure, there are problems such as incomplete longitudinal flame retardancy, the discrete barrier ring is prone to forming flame spread channels, poor anti-interference and heat dissipation coordination, and low charge release efficiency of shielding layer. It is difficult to meet the stringent requirements of flame retardancy, anti-interference, heat dissipation and structural stability at the same time in high-risk scenarios.

[0004] How to invent a composite flame-retardant control cable to improve these problems has become an urgent issue for those skilled in the art. Utility Model Content

[0005] To overcome the above shortcomings, this utility model provides a composite flame-retardant control cable, which aims to improve the problems of incomplete longitudinal flame retardancy, poor anti-interference and heat dissipation coordination, and low charge release efficiency of the shielding layer of existing cables, making it difficult to meet the stringent requirements of flame retardancy, anti-interference, heat dissipation and structural stability in high-risk scenarios.

[0006] This utility model is implemented as follows: A composite flame-retardant control cable includes a conductor core, a double-layer co-extruded insulation layer, a flame-retardant shielding structure layer, and a flame-retardant sheath. The double-layer co-extruded insulation layer, the flame-retardant shielding structure layer, and the flame-retardant sheath are sequentially wrapped around the conductor core from the inside out and are uniformly arranged coaxially. The flame-retardant shielding structure layer includes a wrapped magnetic shielding layer and an electromagnetic shielding braided layer. The wrapped magnetic shielding layer covers the outside of the double-layer co-extruded insulation layer, and the electromagnetic shielding braided layer covers the outside of the wrapped magnetic shielding layer. Several grounding leads extending along the axial direction of the conductor core are arranged between the wrapped magnetic shielding layer and the electromagnetic shielding braided layer.

[0007] In a preferred embodiment of this utility model, a plurality of heat-conducting cavities extending axially and uniformly distributed radially are provided between the inner and outer layers of the double-layer co-extruded insulating layer, and each heat-conducting cavity is filled with a heat-conducting strip.

[0008] In a preferred embodiment of this utility model, each of the grounding leads is in close contact with the magnetic shielding layer and the electromagnetic shielding braided layer on both sides, and a plurality of the grounding leads are evenly distributed in a ring between the magnetic shielding layer and the electromagnetic shielding braided layer.

[0009] In a preferred embodiment of this utility model, both ends of each grounding lead wire are electrically connected to a grounding wire assembly.

[0010] In a preferred embodiment of this utility model, the electromagnetic shielding braided layer is covered with an inner flame-retardant layer on its outer side, and the inner flame-retardant layer includes a substrate layer and a flame-retardant adhesive layer disposed on the outer wall of the substrate layer.

[0011] In a preferred embodiment of this utility model, the flame-retardant adhesive layer is coated on the outer wall of the substrate layer in a spiral winding structure.

[0012] In a preferred embodiment of this utility model, the inner wall of the flame-retardant sheath is provided with a plurality of abutting protrusions that are evenly distributed in a ring and extend in the elongation direction, and each abutting protrusion is tightly fitted to the outer wall of the inner flame-retardant layer.

[0013] The beneficial effects of this utility model are as follows: The composite flame-retardant control cable obtained by the above design has the following advantages: When in use, the heat dissipation effect is optimized by using a double-layer co-extruded insulation layer in conjunction with a heat-conducting cavity and heat-conducting strip. The flame-retardant shielding structure layer adopts a composite structure of a wrapped magnetic shielding layer, an electromagnetic shielding braided layer and an embedded grounding lead wire to improve anti-interference ability and charge release efficiency. The inner flame-retardant layer achieves active expansion flame retardancy by spirally coated expansion flame-retardant adhesive. The synergistic effect of each structural layer enables stable operation in scenarios with high requirements for flame retardancy, anti-interference, heat dissipation and structural stability, such as petrochemical industry and subway tunnels, ensuring reliable transmission of control signals or electrical energy. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0015] Figure 1 This is a schematic perspective view of the overall structure provided by the embodiment of this utility model;

[0016] Figure 2 A schematic perspective view of the overall cross-sectional separation structure provided for an embodiment of this utility model;

[0017] Figure 3 A schematic perspective view of the overall cross-sectional separation structure of the double-layer co-extruded insulation layer provided for the embodiments of this utility model;

[0018] Figure 4 A three-dimensional schematic diagram of the overall cross-sectional separation structure of the flame-retardant shielding structure layer provided for an embodiment of this utility model;

[0019] Figure 5 A three-dimensional cross-sectional view of the flame-retardant sheath provided for an embodiment of this utility model.

[0020] In the diagram: 1-Conductor core; 2-Double co-extruded insulation layer; 3-Flame-retardant shielding structure layer; 4-Flame-retardant sheath; 201-Heat-conducting strip; 301-Wrapped magnetic shielding layer; 302-Electromagnetic shielding braided layer; 303-Grounding lead wire; 304-Inner flame-retardant layer; 401-Abutting protrusion. Detailed Implementation

[0021] 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.

[0022] Please see Figures 1 to 5 This utility model provides a technical solution: a composite flame-retardant control cable, including a conductor core 1, a double-layer co-extruded insulation layer 2, a flame-retardant shielding structure layer 3, and a flame-retardant sheath 4. The double-layer co-extruded insulation layer 2, the flame-retardant shielding structure layer 3, and the flame-retardant sheath 4 are sequentially wrapped around the conductor core 1 from the inside out and are uniformly arranged coaxially. The flame-retardant shielding structure layer 3 includes a wrapped magnetic shielding layer 301 and an electromagnetic shielding braided layer 302. The wrapped magnetic shielding layer 301 covers the outside of the double-layer co-extruded insulation layer 2, and the electromagnetic shielding braided layer 302 covers the outside of the wrapped magnetic shielding layer 301. A plurality of grounding leads 303 extending along the axial direction of the conductor core 1 are arranged between the wrapped magnetic shielding layer 301 and the electromagnetic shielding braided layer 302.

[0023] It should be noted that the conductor core 1 is made of multiple strands of annealed soft copper wire with a diameter of 0.1-0.3mm, with flame-retardant talc powder filled in the gaps between the strands, ensuring both conductivity and flexibility while providing primary flame-retardant buffering. The double-layer co-extruded insulation layer 2 is formed in one step through a co-extrusion process. The inner layer is a ceramicized silicone rubber with a thickness of 0.2-0.4mm, which quickly forms a dense ceramic layer to block the flame during combustion. The outer layer is a flame-retardant cross-linked polyethylene with a thickness of 0.3-0.5mm, which combines insulation and flame retardancy. The two layers are coaxially wrapped around the outside of the conductor core 1, providing basic insulation and flame-retardant protection. The flame-retardant shielding structure layer 3 serves as the core composite shielding flame-retardant structure. The magnetic shielding layer 301 is wrapped around the outside of the double-layer co-extruded insulation layer 2 in a spiral manner with an overlap rate of ≥30% using an aluminum-plastic composite tape with a thickness of 0.05-0.1mm. The aluminum layer reflects low-frequency electromagnetic interference. To mitigate interference, the electromagnetic shielding braided layer 302 is woven with tinned copper wires (0.1-0.15mm in diameter) at a braiding density ≥90% around the outer surface of the magnetic shielding layer 301, absorbing high-frequency electromagnetic interference. Together, they achieve full-band electromagnetic interference shielding. Between the magnetic shielding layer 301 and the electromagnetic shielding braided layer 302, 2-4 tinned copper wires (0.2-0.3mm in diameter) are evenly arranged along the axial direction of the conductor core 1 as grounding leads 303. Each grounding lead 303 is in close contact with the aluminum layer of the magnetic shielding layer 301 and the tinned copper wires of the electromagnetic shielding braided layer 302, allowing for rapid conduction of interference charges intercepted by the shielding layer. The flame-retardant sheath 4, made of low-smoke halogen-free flame-retardant polyolefin material, is extruded over the flame-retardant shielding structure layer 3, with a thickness of 0.8-1.2mm, providing the outermost flame retardant, wear-resistant, and environmental protection. This ensures the cable maintains both signal stability and fire safety in high-risk environments.

[0024] Please see Figures 2 to 5 A number of heat-conducting cavities extending axially and evenly distributed radially are provided between the inner and outer layers of the double-layer co-extruded insulating layer 2, and each heat-conducting cavity is filled with a heat-conducting strip 201.

[0025] During the co-extrusion molding of the inner ceramicized silicone rubber and the outer flame-retardant cross-linked polyethylene of the double-layer co-extruded insulation layer 2, 4-6 radially distributed heat-conducting cavities with a diameter of 0.1-0.2 mm are simultaneously opened between the two layers along the axial direction. Each heat-conducting cavity is filled with a heat-conducting strip 201 made of high thermal conductivity silicone. When the conductor core 1 is energized and heats up or is subjected to heat transfer from the external environment, the heat is transferred through the inner ceramicized silicone rubber to the heat-conducting strip 201, and then quickly conducted by the heat-conducting strip 201 to the outer flame-retardant cross-linked polyethylene, and then dissipated to the flame-retardant shielding structure layer 3 and the outside world. At the same time, the heat-conducting cavity provides deformation buffer space for the insulation layer, enhancing the cable's bending resistance. Under the premise of ensuring insulation and flame retardancy, the synergistic optimization of insulation, flame retardancy and heat dissipation is achieved.

[0026] Furthermore, each grounding lead 303 is in close contact with the magnetic shielding layer 301 and the electromagnetic shielding braided layer 302 on both sides, and several grounding lead 303 are evenly distributed in a ring between the magnetic shielding layer 301 and the electromagnetic shielding braided layer 302.

[0027] After the magnetic shielding layer 301 is wrapped with aluminum-plastic composite tape, several grounding leads 303 are laid parallel to the axial direction of the conductor core 1 on the outer surface of the magnetic shielding layer 301, ensuring tight adhesion with the aluminum layer of the magnetic shielding layer 301. Then, the electromagnetic shielding braided layer 302 is braided. The tension of the braiding machine is used to tightly press the tinned copper wire braided layer onto the grounding leads 303, creating multi-point cross contact between the tinned copper wire of the electromagnetic shielding braided layer 302 and the grounding leads 303. This ensures that each grounding lead 303 simultaneously achieves low-resistance, tight contact with both sides of the magnetic shielding layer 301 and the electromagnetic shielding braided layer 302. Furthermore, the grounding leads 303 are evenly distributed in a ring along the circumference, ensuring uniform conduction of interference charges in all circumferential directions. This allows the electromagnetic interference charges intercepted by the shielding layer to be conducted to the grounding leads 303 through the shortest path. The tight contact and uniform distribution of the grounding leads enhance the cable's electromagnetic interference resistance and ensure the accuracy of control signal transmission.

[0028] Furthermore, each grounding lead 303 is electrically connected to the grounding assembly at both ends.

[0029] At both ends of the cable joint, the outer layers, including the flame-retardant sheath 4 and the inner flame-retardant layer 304, are stripped to expose the flame-retardant shielding layer 301, the electromagnetic shielding braided layer 302, and the grounding lead-in wire 303. Both ends of each grounding lead-in wire 303 are connected to a copper grounding terminal by crimping or welding. Simultaneously, the aluminum layer wrapping the magnetic shielding layer 301 and the tinned copper wire of the electromagnetic shielding braided layer 302 are fixed to the grounding terminal. The grounding terminal is then connected to the field grounding busbar or grounding grid via a multi-strand copper core grounding wire. In this way, interference charges conducted by the grounding lead-in wire 303 can be quickly released to the ground through the grounding assembly, preventing residual charges from causing secondary interference. It also releases static electricity generated during cable operation due to friction and electromagnetic induction, eliminating the risk of electrostatic discharge in flammable and explosive environments. This ensures the cable's anti-interference performance and operational safety at the system level.

[0030] Furthermore, the electromagnetic shielding braided layer 302 is covered with an inner flame-retardant layer 304, which includes a substrate layer and a flame-retardant adhesive layer disposed on the outer wall of the substrate layer.

[0031] The inner flame-retardant layer 304 uses a 0.1-0.2mm thick flame-retardant fiberglass cloth as its base layer, which is wrapped around the outside of the electromagnetic shielding braided layer 302 using a winding process. The high temperature resistance and flame retardancy of the fiberglass cloth provide structural support. A 0.05-0.1mm thick intumescent flame-retardant adhesive is coated around the outer wall of the base layer as a flame-retardant layer. At room temperature, the flame-retardant adhesive layer is flexible and tightly bonded to the base layer. In the event of a fire, it rapidly expands 5-10 times to form a dense charcoal flame-retardant barrier, preventing the flames from spreading into the cable. This achieves an active expansion flame-retardant effect, enhancing the cable's protective capabilities in fire scenarios.

[0032] Furthermore, the flame-retardant adhesive layer is coated on the outer wall of the substrate layer in a spiral winding structure.

[0033] When applying the flame-retardant adhesive layer, a spiral winding process is used. The intumescent flame-retardant adhesive is applied to the outer wall of the flame-retardant fiberglass cloth substrate layer with a pitch of 5-10mm and an overlap rate of ≥20%, forming a continuous and overlapping spiral band on the outer wall of the substrate layer. When the cable is subjected to bending or tensile forces, the spiral structure of the flame-retardant adhesive layer, due to its good deformation adaptability, is not prone to cracking or falling off, ensuring the integrity of the flame-retardant layer. In the event of a fire, the spirally wound flame-retardant adhesive layer expands, forming overlapping expanded char layers in the circumferential direction, avoiding flame-retardant blind spots. The spiral winding process optimizes the structure of the flame-retardant adhesive layer, making it better adaptable to cable operating conditions and fire scenarios, improving structural stability and flame-retardant effect.

[0034] Furthermore, the inner wall of the flame-retardant sheath is provided with several abutting protrusions 401 that are evenly distributed in a ring and extend in the elongation direction. Each abutting protrusion 401 is tightly attached to the outer wall of the inner flame-retardant layer 304.

[0035] When the flame-retardant sheath 4 is extruded from low-smoke halogen-free flame-retardant polyolefin material, 3-5 evenly distributed, ring-shaped abutment protrusions 401 extending along the length are simultaneously formed on its inner circumference. During cable assembly, the flame-retardant sheath 4 is fitted over the outer side of the inner flame-retardant layer 304, ensuring that each abutment protrusion 401 is tightly fitted to the outer wall of the flame-retardant adhesive layer of the inner flame-retardant layer 304. At room temperature, the abutment protrusions 401 are embedded in the flexible flame-retardant adhesive layer to form a protrusion and groove interlocking structure, restricting the relative sliding between layers along the circumference or axis. At the same time, the gaps between the abutment protrusions 401 form micro-air ducts, assisting in the dissipation of internal heat from the cable to the outside, and the protrusions increase the heat dissipation area of ​​the inner surface of the flame-retardant sheath 4. In case of fire, the abutment protrusions 401 fill the tiny gaps between the sheath and the inner flame-retardant layer, preventing flame penetration and guiding the uniform expansion of the flame-retardant adhesive layer to ensure the continuity of the flame-retardant barrier.

[0036] Working principle: The conductor core 1 transmits electrical energy or control signals, and the flame-retardant talc powder in its stranded gaps provides primary flame retardancy; the inner ceramicized silicone rubber and outer flame-retardant cross-linked polyethylene of the double-layer co-extruded insulation layer 2 provide insulation protection, and the heat-conducting strip 201 in the interlayer heat-conducting cavity quickly dissipates heat from the conductor core and insulation layer; the wrapped magnetic shielding layer 301 of the flame-retardant shielding structure layer 3 reflects low-frequency electromagnetic interference, and the electromagnetic shielding braided layer 302 absorbs high-frequency electromagnetic interference. The grounding lead-in wire 303, which is in close contact between the two, quickly dissipates the intercepted interference charge through the grounding wire assemblies at both ends. Rapid release; the flame-retardant glass fiber cloth substrate layer of the inner flame-retardant layer 304 provides support, and the spirally coated intumescent flame-retardant adhesive expands rapidly upon contact with fire to form a dense charcoal flame-retardant barrier; the abutting protrusion 401 of the outermost flame-retardant sheath 4 tightly engages with the inner flame-retardant adhesive layer, which not only restricts relative sliding between layers and assists in heat dissipation, but also fills the gaps between layers to block flame penetration. The synergistic effect of each structural layer enables the cable to ensure stable transmission of signals or electrical energy while possessing anti-electromagnetic interference, efficient heat dissipation and multi-level flame-retardant performance, meeting the usage requirements in high-risk scenarios.

[0037] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A composite flame-retardant control cable, comprising a conductor core, a double-layer co-extruded insulation layer, a flame-retardant shielding structure layer, and a flame-retardant sheath, characterized in that, The double-layer co-extruded insulation layer, flame-retardant shielding structure layer, and flame-retardant sheath are sequentially wrapped around the core from the inside out and are uniformly arranged coaxially. The flame-retardant shielding structure layer includes a wrapped magnetic shielding layer and an electromagnetic shielding braided layer. The wrapped magnetic shielding layer covers the outside of the double-layer co-extruded insulation layer, and the electromagnetic shielding braided layer covers the outside of the wrapped magnetic shielding layer. Several grounding leads extending along the core axis are arranged between the wrapped magnetic shielding layer and the electromagnetic shielding braided layer.

2. The composite flame-retardant control cable as described in claim 1, characterized in that: The inner and outer layers of the double-layer co-extruded insulating layer are provided with several heat-conducting cavities that extend axially and are uniformly distributed radially, and each heat-conducting cavity is filled with a heat-conducting strip.

3. The composite flame-retardant control cable as described in claim 1, characterized in that: Each of the grounding leads is in close contact with the magnetic shielding layer and the electromagnetic shielding braided layer on both sides, and the grounding leads are evenly distributed in a ring between the magnetic shielding layer and the electromagnetic shielding braided layer.

4. The composite flame-retardant control cable as described in claim 1, characterized in that: Each of the grounding leads is electrically connected to a grounding assembly at both ends.

5. The composite flame-retardant control cable as described in claim 1, characterized in that: The electromagnetic shielding braided layer is covered with an inner flame-retardant layer, which includes a substrate layer and a flame-retardant adhesive layer disposed on the outer wall of the substrate layer.

6. The composite flame-retardant control cable as described in claim 5, characterized in that: The flame-retardant adhesive layer is coated on the outer wall of the substrate layer in a spiral winding structure.

7. The composite flame-retardant control cable as described in claim 5, characterized in that: The flame-retardant sheath has several evenly distributed, ring-shaped abutting protrusions on its inner wall, each of which is tightly fitted to the outer wall of the inner flame-retardant layer.

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