A fire resistant cable having a physical fire barrier

Abstract

The present application relates to cable technical field, and disclose a kind of fire-retardant cable with physical fire barrier;The present application is provided with fire ring, when the sheath layer between adjacent fire ring is ignited, only a part of sheath layer can be burned under the action of fire ring, at the same time, when the sheath layer is burned and loses supporting force, support spring pushes support ring to move horizontally at this time, the sheath layer that burns is pushed away from the sheath layer that is not ignited, with the movement of support ring, capsule release shell starts to move away from fire-retardant capsule, when fire-retardant capsule is completely opened, the expandable graphite in fire-retardant capsule begins to react and form porous worm-like carbon body, after the expansion of expandable graphite, the interval between support ring and fire ring is filled, to form fire barrier, so that flame is away from adjacent sheath layer, at the same time, through heat absorption of expansion, the heat transfer is reduced by the low thermal conductivity of carbon body, to realize the double effect of fire prevention and heat insulation.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and in particular to a flame-retardant cable with a physical fire barrier. Background Technology

[0002] Cables are flexible conductive structures used to transmit electrical energy or signals. They are typically composed of a conductive core, an insulation layer, a protective layer, and other core components. They can enable the supply of power, data, and signals between different devices or areas in scenarios such as power systems, communication networks, and industrial equipment. Furthermore, the structure and materials can be adjusted according to the laying environment, combining conductivity, insulation, and environmental adaptability.

[0003] According to Chinese Patent Publication No. CN219180264U, this utility model relates to the field of cable technology, specifically to an aluminum-sheathed flexible fireproof cable, including an outer sheath mechanism and a cable mechanism, wherein the cable mechanism is placed inside the outer sheath mechanism; the outer sheath mechanism includes an outer sheath, a first fire-retardant sleeve, a second fire-retardant sleeve, a first wrapping tape, an aluminum sheath, and a second wrapping tape. This utility model overcomes the shortcomings of the prior art. Both the first and second fire-retardant sleeves are filled with fire-retardant powder, and both have fine holes. After the outer sheath is ignited, the first and second fire-retardant sleeves will burn, exposing the internal fire-retardant powder. The fire-retardant powder is aluminum hydroxide flame-retardant powder. When heated, aluminum hydroxide flame-retardant powder can release a large amount of water vapor. The large amount of water vapor can store heat and dilute the concentration of flammable polymer gases, and can also form a non-combustible barrier between the combustion source and the matrix material, thereby achieving the purpose of flame retardancy.

[0004] Regarding the above and existing related technologies, the inventors believe that the following defects often exist: When existing flame-retardant cables with physical fire barriers are used, if the cable sheath is ignited by a flame, the flame will continue to burn along the sheath, resulting in electrical safety problems such as short circuits and leakage. The spread of flames along the cable can cause secondary fires, leading to problems such as failure of critical equipment and system paralysis. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that when the cable sheath is ignited by a flame, the flame will continue to burn along the sheath. To address this, we propose a flame-retardant cable with a physical fire barrier.

[0006] To achieve the above objectives, this application adopts the following technical solution: a flame-retardant cable with a physical fire barrier, comprising a cable core, a filling layer surrounding the outer wall of the cable core, an insulation layer surrounding the outer wall of the filling layer, a fire-retardant layer surrounding the outer wall of the insulation layer, a sheath layer surrounding the outer wall of the fire-retardant layer, a fire-retardant ring provided on the side of the sheath layer, a spring groove provided inside the fire-retardant ring, a capsule groove provided on the side of the spring groove, a support spring fixedly connected to the inner wall of the spring groove, a flame-retardant capsule fixedly connected to the inner wall of the capsule groove, a capsule release shell engaged on the side of the flame-retardant capsule, and a support ring fixedly connected to the other side of the capsule release shell.

[0007] Preferably, the fire-arresting ring and the fire-arresting layer are fixedly connected, and the fire-arresting rings are spaced evenly with respect to the outer wall of the fire-arresting layer.

[0008] Preferably, both the flame arresting ring and the flame arresting layer are made of nickel-chromium alloy, and the outer diameter of the flame arresting ring is larger than the outer diameter of the sheath layer.

[0009] Preferably, the capsule slot is located on the side of the flame arrestor ring, and the capsule slot is symmetrically arranged about the vertical central axis of the spring slot.

[0010] Preferably, there is a one-to-one correspondence between the spring groove and the support spring, and the diameter of the spring groove is larger than the diameter of the support spring.

[0011] Preferably, the support spring is located between the spring groove and the support ring, and the support spring and the support ring are fixedly connected.

[0012] Preferably, there is a one-to-one correspondence between the flame-retardant capsule and the capsule groove, and the outer diameter of the flame-retardant capsule is equal to the inner diameter of the capsule groove.

[0013] Preferably, the flame-retardant capsule is hollow and its interior is filled with expandable graphite material.

[0014] Preferably, the support rings are arranged in six pairs at equal angles with respect to the horizontal central axis of the fire-arresting ring, and the inner diameter of the support rings is equal to the outer diameter of the fire-arresting layer.

[0015] Preferably, the support ring and the sheath layer are tightly fitted together, and the support ring is arranged in a ring shape.

[0016] The technical effects and advantages of this invention are as follows: This invention incorporates flame-arresting rings. When the sheath layer between adjacent flame-arresting rings is ignited, only a portion of the sheath layer burns under the action of the flame-arresting rings. Simultaneously, when the sheath layer loses its supporting force due to combustion, the supporting spring pushes the supporting ring horizontally, pushing the burning sheath layer away from the unignited sheath layer. As the supporting ring moves, the capsule release shell begins to move away from the flame-arresting capsule. When the flame-arresting capsule is fully opened, the expandable graphite inside the capsule begins to react, forming a porous, worm-like carbon body. After expanding, the expandable graphite fills the gap between the supporting ring and the flame-arresting ring, forming a flame-arresting barrier, thus keeping the flame away from adjacent sheath layers. Simultaneously, through expansion and heat absorption, and the low thermal conductivity of the carbon body, heat transfer is reduced, achieving both flame-arresting and heat-insulating effects. Attached Figure Description

[0017] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts:

[0018] Figure 1 This is a front view structural diagram of the flame-retardant cable with a physical fire barrier according to the present invention. Figure 2 This is a schematic diagram of the exploded structure of the flame-retardant cable with a physical fire barrier according to the present invention. Figure 3 This is an enlarged structural schematic diagram of the cable core portion of the present invention; Figure 4 This is an enlarged structural schematic diagram of the fire-retardant layer portion of the present invention; Figure 5 This is a schematic diagram of the disassembly structure of the fire-retardant layer portion of the present invention; Figure 6 This is an enlarged structural schematic diagram of the flame arrestor ring portion of the present invention; Figure 7 This is an exploded structural diagram of the support ring portion of the present invention; Figure 8 This is a schematic diagram of the exploded structure of the flame-retardant capsule portion of the present invention.

[0019] Legend: 1. Cable core; 2. Filler layer; 3. Insulation layer; 4. Flame-retardant layer; 5. Sheath layer; 6. Flame-retardant ring; 7. Spring groove; 8. Capsule groove; 9. Support spring; 10. Flame-retardant capsule; 11. Capsule release shell; 12. Support ring. Detailed Implementation

[0020] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0021] According to the embodiments of the present invention, Figures 1 to 8As shown.

[0022] While existing flame-retardant cables with physical fire barriers enhance fire resistance through built-in fire-retardant structures, in actual use, if exposed to direct high-temperature flames, the cable sheath layer 5 can be ignited. The flames will continue to burn along the sheath layer 5, leading to electrical safety issues such as short circuits and leakage. The spread of flames along the cable can cause secondary fires, resulting in critical equipment failure and system paralysis. The burning sheath can quickly ignite surrounding cables and combustibles, causing even greater losses. The continuous burning of the sheath layer 5 releases large amounts of toxic gases and high-concentration black smoke, causing poisoning and unconsciousness in personnel. The dense smoke significantly reduces environmental visibility, obstructs evacuation routes, and causes people to lose their way during escape, increasing the risk of trampling and entrapment. To solve this problem, this invention incorporates the following design into flame-retardant cables with physical fire barriers.

[0023] A flame-retardant cable with a physical fire barrier includes a cable core 1, which is the core functional carrier of the cable, mainly responsible for transmitting electrical energy or signals. It is the key part that determines the cable's conductivity and signal transmission capabilities, directly affecting the cable's transmission efficiency, voltage level, and safety performance. The outer wall of the cable core 1 is surrounded by a filling layer 2, and the outer wall of the filling layer 2 is surrounded by an insulation layer 3. The insulation layer 3 is the core safety protection layer of the cable, wrapping around the conductive core. Its core function is to isolate the conductive core from external current flow, preventing electrical safety accidents such as leakage and short circuits, while also protecting the core from environmental factors. It is a key structure for the cable to achieve safe power transmission and signal transmission. The outer wall of the insulation layer 3 is surrounded by a fire-retardant layer 4, a functional structural layer in the cable used to actively block the spread of flames and isolate high temperatures and oxygen. Its core function is to block the flames from reaching the cable during a fire through its own material properties or structural action. The fire-resistant layer 4 is a key component for improving the fire resistance of cables. It can spread internally or along the cable axis, delaying or even preventing the spread of fire and buying time for emergency rescue, equipment power outage, or personnel evacuation. The outer wall of the fire-resistant layer 4 is surrounded by the sheath layer 5. The sheath layer 5 is the outermost protective structure of the cable, wrapping around the cable core 1, insulation layer 3, and armor layer. Its core function is to isolate the cable from external environmental erosion and resist mechanical damage. At the same time, it helps to improve the fire resistance and weather resistance of the cable. It is an outer barrier that protects the key internal structure of the cable and extends the service life of the cable. The sheath layer 5 is provided with a fire-resistant ring 6 on its side. The fire-resistant ring 6 has a spring groove 7 inside. The spring groove 7 has a capsule groove 8 on its side. The inner wall of the spring groove 7 is fixedly connected to a support spring 9. The inner wall of the capsule groove 8 is fixedly connected to a flame-retardant capsule 10. The side of the flame-retardant capsule 10 is engaged with a capsule release shell 11. The other side of the capsule release shell 11 is fixedly connected to a support ring 12.

[0024] The flame-arresting ring 6 and the flame-arresting layer 4 are fixedly connected. The flame-arresting ring 6 is evenly spaced relative to the outer wall of the flame-arresting layer 4. Both the flame-arresting ring 6 and the flame-arresting layer 4 are made of nickel-chromium alloy. Nickel-chromium alloy has a high melting point and high temperature resistance. It is non-combustible and does not melt in flames. It can form a rigid fire barrier in the form of foil, wire, etc., directly blocking the penetration and spread of flames. Its chromium content forms a dense oxide film at high temperatures, and its low thermal conductivity reduces heat transfer to the inner core 1 of the cable, assisting in heat insulation and protection of the insulation layer 3. It also has a certain degree of flexibility. This design is suitable for cable bending installations and fire-retardant applications. The outer diameter of the fire-retardant ring 6 is larger than the outer diameter of the sheath layer 5. The capsule groove 8 is located on the side of the fire-retardant ring 6 and is symmetrically arranged about the vertical central axis of the spring groove 7. There is a one-to-one correspondence between the spring groove 7 and the support spring 9. The diameter of the spring groove 7 is larger than the diameter of the support spring 9. The support spring 9 is located between the spring groove 7 and the support ring 12, and the support spring 9 and the support ring 12 are fixedly connected. The flame-retardant capsule 10 corresponds one-to-one with the capsule groove 8. The outer diameter of the flame-retardant capsule 10 is equal to the inner diameter of the capsule groove 8. The flame-retardant capsule 10 is hollow and filled with expandable graphite material. Expandable graphite is a layered carbon material produced by inserting intercalating agents such as acids and oxidants between the layers of natural graphite and then treating it at high temperature. Its core characteristic is that when heated, the intercalating agents rapidly decompose to generate gas, which pushes the graphite layers to peel off, causing the volume to expand rapidly and form a loose, porous, worm-like carbon body. This carbon body has the characteristics of high temperature resistance, non-combustibility, and low thermal conductivity. The fire-resistant layer 12 can fill gaps to form a physical fire barrier, blocking the contact between flames and oxygen, and can also absorb heat and cool down through the expansion process. It is widely used in cable fire-resistant layers 4, fire-retardant coatings and other fields. It has both fire-resistant and heat-insulating functions, and is environmentally friendly and halogen-free. It is suitable for fire protection needs in densely populated or enclosed environments. There are six pairs of support rings 12 at the same angle to the horizontal central axis of the fire-resistant ring 6. The inner diameter of the support ring 12 is equal to the outer diameter of the fire-resistant layer 4. The support ring 12 is tightly fitted to the sheath layer 5. The support ring 12 is ring-shaped.

[0025] During cable use, when the sheath layer 5 is exposed to fire, due to the flame-retardant properties of the flame-arresting rings 6, only the sheath layer 5 between adjacent flame-arresting rings 6 can burn. The flame-arresting layer 4 is used to prevent the flame from spreading to the inner layer of the cable. However, when the flame is large, it may still ignite adjacent sheath layers 5. As the sheath layer 5 burns, the supporting force of the sheath layer 5 on the support ring 12 decreases due to the loss of the sheath layer 5. At this time, the elasticity of the support spring 9 is released, pushing the support ring 12 to slide on the outer wall of the flame-arresting layer 4, pushing the burning sheath layer 5 away from the position of the flame-arresting rings 6, and increasing the distance between adjacent sheath layers 5. At the same time, as the support ring 12 moves, it causes the capsule release shell 11 to move away from the flame-retardant capsule 10. When the opening of the flame-retardant capsule 10 opens, the expandable graphite inside the flame-retardant capsule 10 begins to react. The expandable graphite decomposes rapidly when heated, releasing a large amount of gas. Under the thrust of the gas, the originally layered expandable graphite undergoes significant interlayer delamination, gradually forming a loose and porous worm-like carbon body. This process is accompanied by significant volume expansion, and the carbon body itself has good high-temperature resistance. After the expandable graphite completes its expansion and transforms into a worm-like carbon body, it will quickly fill the gap between the support ring 12 and the flame arrestor ring 6 due to its own expansion characteristics. The loose and porous worm-like carbon body can closely adhere to the outer wall of the support ring 12 and the inner wall of the flame arrestor ring 6, filling the gaps and voids between them, forming a continuous and gapless filling layer 2. This carbon body itself is non-combustible and non-melting, and can effectively block the flow of oxygen. At the same time, its extremely low thermal conductivity can significantly reduce the conduction of external heat to the cable core, building a fire barrier between the support ring 12 and the flame arrestor ring 6, preventing the flame from spreading along the gap, and protecting the cable body from high-temperature damage.

[0026] Within the outer protective structure of the cable, flame-arresting rings 6 are specially installed. These rings are spaced apart along the cable's axial direction, forming a series of fire-resistant barriers. When the sheath layer 5 between adjacent flame-arresting rings 6 is ignited, the flame-arresting rings 6, with their non-combustible and high-temperature resistant material properties, can directly block the flame from spreading to both sides, preventing the flame from breaking through the limitations of the flame-arresting rings 6. This ensures that only a localized portion of the sheath layer 5 between two flame-arresting rings 6 is in a burning state, effectively controlling the initial spread of the flame and preventing the fire from expanding rapidly. Simultaneously, as the sheath layer 5 continues to burn, its polymer material gradually melts and carbonizes, significantly reducing or even completely eliminating its original support for the cable's internal structure. When the sheath layer 5 loses its support due to burning, the support spring 9, freed from the constraint of the sheath layer 5, releases its elastic potential energy, generating a horizontal thrust that pushes the connected support spring 9. The ring 12 moves along the cable axis, pushing the burning sheath layer 5 away from the unburned sheath layer 5, completely separating it from the unburned sheath layer 5. Through physical isolation, it cuts off the heat transfer between the burning area and the unburned area, preventing the unburned sheath layer 5 from being ignited by contact with high-temperature flames or molten drips, further reducing the scope of the fire and reducing the continuous supply of combustibles. As the support ring 12 moves, the capsule release shell 11 begins to move away from the flame-retardant capsule 10. When the flame-retardant capsule 10 is fully opened, the expandable graphite inside the flame-retardant capsule 10 begins to react to form a porous worm-like carbon body. After the expandable graphite expands, it fills the gap between the support ring 12 and the flame-retardant ring 6, forming a flame-retardant barrier, which keeps the flame away from the adjacent sheath layer 5. At the same time, through expansion and heat absorption, and the low thermal conductivity of the carbon body, it reduces heat transfer, achieving the dual effects of flame-retardant and heat insulation.

[0027] The flame arrestor ring 6 can directly act as a physical firewall. When the sheath layer 5 between adjacent flame arrestor rings 6 is ignited, it effectively prevents the flame from spreading across the rings, allowing only a localized portion of the sheath layer 5 to burn. This cuts off the path of flame propagation along the cable axis from the source, preventing the flame from breaching the fire compartment and igniting surrounding cables or combustibles, thus avoiding a small-scale fire from escalating into a large-scale fire. When the burning sheath layer 5 loses its support due to high temperature, the support spring 9 can actively push the support ring 12 to move horizontally, directly pushing the burning sheath layer 5 away from the unignited portion of the sheath layer 5. This mechanical action physically separates the fire source area from the safe area, preventing unburned sheath layers from being ignited by contact with high-temperature flames or molten drips, further reducing the fire's impact range and decreasing the fuel supply for continued fire combustion. During the movement of the support ring 12, it will cause the capsule release shell 11 to move away from the flame-retardant capsule 10, allowing the capsule to fully open. The internal expandable graphite reacts rapidly upon heating. A porous, worm-like carbon body is formed, tightly filling the gap between the support ring 12 and the flame-arresting ring 6. This carbon body not only physically blocks oxygen flow and prevents flame penetration, forming a stable flame-arresting barrier, but also reduces local temperature through the heat absorption effect during expansion. At the same time, its low thermal conductivity reduces the transfer of external high temperature to the cable core 1, preventing the core insulation layer 3 from melting and carbonizing due to high temperature failure, thereby reducing electrical safety risks such as short circuits and leakage, and ensuring the short-term stability of the cable's core functions. All actions rely solely on flame heat triggering and mechanical structure linkage, requiring no electrical or manual intervention, resulting in a fast response speed. Furthermore, the core flame-arresting material, expandable graphite, is an environmentally friendly, halogen-free material that does not release toxic gases or dense smoke during combustion or expansion, reducing the smoke toxicity at the fire scene, buying sufficient time for personnel evacuation and fire rescue, and reducing fire damage to equipment and buildings, minimizing casualties and property losses.

[0028] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A flame-retardant cable with a physical fire barrier, characterized in that, The cable includes an inner core, an outer wall surrounded by a filling layer, an outer wall surrounded by an insulation layer, an outer wall surrounded by a flame-retardant layer, and an outer wall surrounded by a sheath layer. A flame-retardant ring is provided on the side of the sheath layer. A spring groove is formed inside the flame-retardant ring, and a capsule groove is provided on the side of the spring groove. A support spring is fixedly connected to the inner wall of the spring groove, and a flame-retardant capsule is fixedly connected to the inner wall of the capsule groove. A capsule release shell is engaged on the side of the flame-retardant capsule, and a support ring is fixedly connected to the other side of the capsule release shell. The support ring and the sheath layer are tightly fitted together, and the support ring is annular. The spring is located between the spring groove and the support ring. The support spring and the support ring are fixedly connected. The inner diameter of the support ring is equal to the outer diameter of the flame-retardant layer. When the sheath layer is burned and loses its support, the support spring pushes the support ring to move horizontally, pushing the burning sheath layer away from the unignited sheath layer. As the support ring moves, the capsule release shell begins to move away from the flame-retardant capsule. The flame-retardant capsule is hollow and filled with expandable graphite material. When the flame-retardant capsule opens, the expandable graphite inside the flame-retardant capsule begins to react and form porous worm-like carbon bodies. After the expandable graphite expands, it fills the gap between the support ring and the flame-retardant ring, forming a flame-retardant barrier.

2. The flame-retardant cable with a physical fire barrier according to claim 1, characterized in that: The fire-arresting rings are fixedly connected to the fire-arresting layer, and the fire-arresting rings are evenly spaced about the outer wall of the fire-arresting layer.

3. The flame-retardant cable with a physical fire barrier according to claim 1, characterized in that: Both the flame arresting ring and the flame arresting layer are made of nickel-chromium alloy, and the outer diameter of the flame arresting ring is larger than the outer diameter of the sheath layer.

4. The flame-retardant cable with a physical fire barrier according to claim 1, characterized in that: The capsule slot is located on the side of the flame arrestor ring, and the capsule slot is symmetrically arranged about the vertical central axis of the spring slot.

5. The flame-retardant cable with a physical fire barrier according to claim 1, characterized in that: There is a one-to-one correspondence between the spring groove and the support spring, and the diameter of the spring groove is larger than the diameter of the support spring.

6. The flame-retardant cable with a physical fire barrier according to claim 1, characterized in that: There is a one-to-one correspondence between the flame-retardant capsule and the capsule groove, and the outer diameter of the flame-retardant capsule is equal to the inner diameter of the capsule groove.

7. The flame-retardant cable with a physical fire barrier according to claim 1, characterized in that: The support ring is provided in six pairs at equal angles with respect to the horizontal central axis of the flame arrester ring.

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