A fire resistant cable

Abstract

This invention discloses a fire-resistant cable, comprising an inner core and an outer sheath composed of one or more arc-shaped splicing portions. Each adjacent arc-shaped splicing portion has a receiving cavity on its splicing surface, and a flexible protective layer is disposed within each cavity. The two sides of the flexible protective layer are respectively embedded in the arc-shaped splicing portions and fixed with adhesive. Adjacent arc-shaped splicing portions are spliced ​​together. A telescopic shaft is provided between the inner core and the outer sheath, comprising an upper shaft and a lower shaft, which are slidably connected. Magnet assemblies are disposed at both ends of the telescopic shaft, and the magnet assemblies are connected by springs. When an external fire occurs, the outer sheath can be ejected; when an internal fire occurs, the outer sheath can be contracted inward to extinguish the internal flames, thus providing better fire resistance.

Description

Technical Field

[0001] This invention relates to the field of cables, and more specifically to a fire-resistant cable. Background Technology

[0002] Wires and cables are wire products used to transmit electrical (magnetic) energy, information, and realize the conversion of electromagnetic energy. In a broad sense, wires and cables are also simply called cables. In a narrow sense, a cable refers to an insulated cable, which can be defined as: an assembly consisting of one or more insulated cores, and each of them may have a sheath, a protective layer, and an outer sheath. Cables may also have additional uninsulated conductors. Current technology mainly improves the sheath, protective layer, and outer sheath by developing flame-retardant materials to be added to the sheath and protective layer. However, the multi-layered insulation structure of wires and cables does not allow for the addition of flame-retardant materials to every layer. This can mitigate spontaneous combustion caused by overheating to some extent, but it cannot completely prevent it. Overheating can still ignite parts of the sheath or protective layer, potentially igniting external objects and causing a fire. External ignition sources can only prevent the sheath from being ignited; the protective layer will not be ignited. If the outer sheath of the wire or cable is damaged or broken, it can still be ignited.

[0003] There are many existing technologies that can improve its fire resistance.

[0004] For example, Chinese patent application number 201910932799.0 discloses a composite cable, including an outer sheath composed of one or more arc-shaped splicing parts. Each adjacent arc-shaped splicing part has a receiving cavity on its splicing surface, and a flexible protective layer is disposed within each cavity. The two sides of the flexible protective layer are respectively embedded in the arc-shaped splicing parts and fixed with adhesive. Adjacent arc-shaped splicing parts are spliced ​​together. The outer sheath has a mounting cavity in the middle, and a cable core wire is installed within the mounting cavity. One or more fixing bushings protrude from the outer protective layer of the cable core wire. A spring is inserted into each bushing, extending beyond the fixed bushing and connected to a magnetic attraction part. A connecting rod is fixed to the other end of the magnetic attraction part, and the other end of the connecting rod is inserted into the arc-shaped splice and fixed. The magnetic attraction part and the end face of the fixed bushing are attracted and fixed by a magnetic structure, causing the spring to be pressed into the fixed bushing. The magnetic structure includes a magnetic attraction part and a metal sheet. The metal sheet is embedded in the top end face of the fixed bushing, and the magnetic attraction part and the metal sheet are attracted and fixed. The magnetic attraction part uses a magnet block, which is a neodymium iron boron magnet. The attraction force of the magnetic structure is greater than the elastic force of the compressed spring.

[0005] The aforementioned improvements allow the outer cladding to pop out in the event of an external fire, providing good fire resistance. However, they cannot extinguish fires that start inside the cladding. Summary of the Invention

[0006] Purpose of the invention: In order to overcome the problems existing in the prior art, the present invention provides a fireproof cable that can pop out the outer sheath when the outside is on fire and can retract the outer sheath inward when the inside is on fire, thereby extinguishing the internal flames and having better fireproof performance.

[0007] To solve the above problems, the present invention adopts the following technical solution:

[0008] A fire-resistant cable includes an inner core and an outer sheath composed of one or more arc-shaped splicing portions. Each adjacent arc-shaped splicing portion has a receiving cavity on its splicing surface, and a flexible protective layer is disposed within each cavity. The two sides of the flexible protective layer are respectively embedded in the arc-shaped splicing portions and fixed with adhesive. Adjacent arc-shaped splicing portions are spliced ​​together. A telescopic shaft is provided between the inner core and the outer sheath. The telescopic shaft includes an upper shaft and a lower shaft, which are slidably connected. Magnet assemblies are disposed at both ends of the telescopic shaft and connected by springs. Each magnet assembly includes a first magnet assembly and a second magnet assembly. The first magnet assembly includes two mutually repelling first magnets connected by a first spring, which is in a compressed state. The second magnet assembly includes a second magnet and an iron sheet, with the second magnet disposed on the side of the telescopic shaft near the outer sheath. The second magnet is connected to the iron sheet by a second spring, which is in a stretched state. The repulsive force between the two first magnets is A, the attractive force between the second magnet and the iron sheet is B, the stretching force of the second spring is C, and the compressive force of the first spring is D. C > D, A + C = B + D, and B + D > C.

[0009] Preferably, the inner core consists of a conductor, a first fireproof layer, and a first insulating layer from the inside out.

[0010] Preferably, the outer sheath consists of a second fireproof layer, a waterproof layer, a second insulating layer, and a protective layer from the inside out.

[0011] Preferably, the two ends of the telescopic shaft are fixed inside the outer sheath and the inner core, respectively.

[0012] Preferably, the lengths of the first spring and the second spring minus their extensions are both greater than or equal to the distance from the inner core to the outer sheath.

[0013] Preferably, the space between the inner core and the outer sheath is filled with an inert gas.

[0014] Preferably, the number of telescopic shafts equipped with the first magnet group and the number of telescopic shafts equipped with the second magnet group are equal and they are staggered and equidistant from each other.

[0015] Working principle: When the external ignition temperature rises to a certain level, the first and second magnets near the outside fail, the repulsive force A between the two first magnets and the attractive force B between the second magnet and the iron sheet fail. At this time, the extension force C of the second spring is greater than the contraction force D of the first spring, and the extension shaft drives the outer layer to move outward.

[0016] When the internal fire temperature rises to a certain level, the first magnet near the inside fails, and the repulsive force A between the two first magnets fails. At this time, the attractive force B between the second magnet and the iron sheet, plus the compression force D of the first spring, is greater than the extension force C of the second spring. The extension shaft drives the outer layer to move inward, extinguishing the internal flame.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following advantages: when the outside is on fire, the outer layer can be ejected, and when the inside is on fire, the outer layer can be contracted inward to extinguish the internal flames, thus having better fireproof performance. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of the present invention along its width.

[0019] Figure 2 This is a cross-sectional view of the present invention along its length.

[0020] Figure 3 This is a cross-sectional view of the core structure of the present invention;

[0021] Figure 4 This is a cross-sectional structural diagram of the outer sheath of the present invention;

[0022] The components are: 1. Inner core; 11. Conductor; 12. First fireproof layer; 13. First insulation layer; 2. Outer sheath; 21. Second fireproof layer; 22. Waterproof layer; 23. Second insulation layer; 24. Protective layer; 3. Telescopic shaft; 4. First magnet assembly; 41. First magnet; 5. First spring; 6. Second magnet assembly; 61. Second magnet; 62. Iron sheet; 7. Second spring. Detailed Implementation

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] like Figure 1-4As shown, a fireproof cable includes an inner core 1 and an outer sheath 2 composed of one or more arc-shaped splicing parts. Each splicing surface of an adjacent arc-shaped splicing part has a receiving cavity, and a flexible protective layer is provided in each receiving cavity. The two sides of the flexible protective layer are respectively embedded in the arc-shaped splicing parts and fixed with glue. Adjacent arc-shaped splicing parts are spliced ​​together. A telescopic shaft 3 is provided between the inner core 1 and the outer sheath 2. The telescopic shaft 3 includes an upper shaft and a lower shaft, which are slidably connected. Magnet groups are provided at both ends of the telescopic shaft 3. The magnet groups are connected by springs. The magnet groups include a first magnet group 4 and a second magnet group 6. The first magnet group 4 includes two mutually repelling first magnets 41, which are connected by a first spring 5. The first spring 5 is in a compressed state. The second magnet group 6 includes a second magnet 61 and an iron sheet 62. The second magnet 61 is located on the side of the telescopic shaft 3 near the outer sheath 2. The second magnet 61 and the iron sheet 62 are connected by the second spring 7. The second spring 7 is in a stretched state. The repulsive force between the two first magnets 41 is A, the attractive force between the second magnet 61 and the iron sheet 62 is B, the stretching force of the second spring 7 is C, and the compressive force of the first spring 5 is D. C > D, A + C = B + D, and B + D > C.

[0025] Preferably, the inner core 1 consists of a conductor 11, a first fireproof layer 12, and a first insulating layer 13 from the inside out.

[0026] Preferably, the outer sheath 2 consists of a second fireproof layer 21, a waterproof layer 22, a second insulating layer 23, and a protective layer 24 from the inside out.

[0027] Preferably, the two ends of the telescopic shaft 3 are fixed inside the outer sheath 2 and the inner core 1, respectively.

[0028] Preferably, the lengths of the first spring 5 and the second spring 7 minus their extensions are both greater than or equal to the distance from the inner core 1 to the outer sheath 2.

[0029] Preferably, the space between the inner core 1 and the outer sheath 2 is filled with an inert gas.

[0030] Preferably, the number of telescopic shafts 3 with the first magnet group 4 and the number of telescopic shafts 3 with the second magnet group 6 are equal and they are staggered and equidistant from each other.

[0031] Working principle: When the external ignition temperature rises to a certain level, the first magnet 41 and the second magnet 61 near the outside fail, the repulsive force A between the two first magnets 41 and the attractive force B between the second magnet 61 and the iron sheet 62 fail, at this time the extension force C of the second spring 7 is greater than the contraction force D of the first spring 5, and the extension shaft 3 drives the outer layer 2 to move outward.

[0032] When the internal fire temperature rises to a certain level, the first magnet 41 near the inside fails, and the repulsive force A between the two first magnets 41 fails. At this time, the attractive force B between the second magnet 61 and the iron plate 62, plus the compression force D of the first spring 5, is greater than the extension force C of the second spring 7. The extension shaft 3 drives the outer layer to move inward, extinguishing the internal flame.

[0033] The purpose of the above embodiments is to reproduce and derive the technical solution of the present invention by way of example, and to fully describe the technical solution, purpose and effect of the present invention. The purpose is to enable the public to have a more thorough and comprehensive understanding of the disclosure of the present invention, and not to limit the scope of protection of the present invention.

[0034] The above embodiments are not an exhaustive list based on the present invention, and there may be many other embodiments not listed. Any substitutions and improvements made without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A fire-resistant cable, comprising an inner core (1) and an outer sheath (2) composed of one or more arc-shaped splicing portions, wherein a receiving cavity is formed on the splicing surface of adjacent arc-shaped splicing portions, and a flexible protective layer is provided in each receiving cavity, wherein the two sides of the flexible protective layer are respectively embedded in the arc-shaped splicing portions and fixed with glue, and adjacent arc-shaped splicing portions are spliced ​​together, characterized in that: A telescopic shaft (3) is provided between the inner core (1) and the outer sheath (2). The telescopic shaft (3) includes an upper shaft and a lower shaft, which are slidably connected. Magnet groups are provided at both ends of the telescopic shaft (3), and the magnet groups are connected by springs. The magnet groups include a first magnet group (4) and a second magnet group (6). The first magnet group (4) includes two mutually repelling first magnets (41), which are connected by a first spring (5) which is in a compressed state. The second magnet group (6) includes a second magnet (61) and an iron sheet (62). 1) Set on the side of the telescopic shaft (3) close to the outer sheath (2), the second magnet (61) and the iron sheet (62) are connected by the second spring (7), the second spring (7) is in a stretched state, the repulsive force between the two first magnets (41) is A, the attractive force between the second magnet (61) and the iron sheet (62) is B, the stretching force of the second spring (7) is C, the contraction force of the first spring (5) is D, C>D, A+C=B+D, B+D>C, the length of the first spring (5) and the second spring (7) minus their stretching amount are both greater than or equal to the distance from the inner core (1) to the outer sheath (2).

2. The fire-resistant cable according to claim 1, characterized in that: The inner core (1) consists of a conductor (11), a first fireproof layer (12), and a first insulating layer (13) from the inside out.

3. A fire-resistant cable according to claim 1 or 2, characterized in that: The outer layer (2) consists of a second fireproof layer (21), a waterproof layer (22), a second insulation layer (23), and a protective layer (24) from the inside out.

4. A fire-resistant cable according to claim 3, characterized in that: The two ends of the telescopic shaft (3) are fixed inside the outer sheath (2) and the inner core (1), respectively.

5. A fire-resistant cable according to claim 1, characterized in that: An inert gas is filled between the inner core (1) and the outer sheath (2).

6. A fire-resistant cable according to claim 1, characterized in that: The telescopic shafts (3) equipped with the first magnet group (4) and the telescopic shafts (3) equipped with the second magnet group (6) are of equal number and are staggered and equidistant from each other.

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