A B1 class flame-retardant low-voltage cable

Abstract

The application discloses a B1-grade flame-retardant low-voltage cable, which comprises a plurality of conductor cores and a first flame-retardant sheath, each of the conductor cores is externally wrapped with an insulating layer, and the insulating layer is externally wrapped with a second flame-retardant sheath, and belongs to the technical field of low-voltage cables.The B1-grade flame-retardant low-voltage cable has the beneficial effects that the second flame-retardant sheath, the first flame-retardant sheath and the third flame-retardant sheath are combined to form a multilayer flame-retardant structure, and the outer sheath is combined with an intumescent foam layer, the outer sheath is encrusted when on fire, thereby forming a heat-insulating and oxygen-insulating protective layer and preventing molten droplets, the internal hydroxide flame retardant absorbs heat, decomposes and releases water vapor, thereby effectively reducing temperature and diluting oxygen, the foam layer sharply expands under high temperature, thereby forming a dense and thick carbonized layer, the carbonized layer physically blocks the flame and the hot air flow channel, thereby achieving asphyxiation and fire extinguishing and blocking heat conduction to the inside, so that the B1-grade flame-retardant standard is reached, and the risk of flame spreading along the cable is reduced.

Description

Technical Field

[0001] This invention relates to the field of low-voltage cable technology, and in particular to a B1-grade flame-retardant low-voltage cable. Background Technology

[0002] Flame-retardant low-voltage power cables are widely used in applications requiring high safety, environmental protection, and temperature resistance. They possess characteristics such as halogen-free, low-smoke, flame-retardant, and temperature-resistant properties, providing safe and reliable power supply for high-rise buildings and residences, protecting residents' lives and property. They are also used in public places such as hospitals, schools, and shopping malls to provide power to facilities and ensure the normal operation of the power system in emergencies. However, in existing flame-retardant power cable designs, the internal insulation layer softens when heated, causing localized water molecules or hydrates in the cable to bulge, deform, or crack, and dripping. This weakens or eliminates the cable's protective capabilities, resulting in poor performance. Therefore, this case study addresses these issues in depth. Summary of the Invention

[0003] The purpose of this invention is to solve the above-mentioned problems by designing a B1-grade flame-retardant low-voltage cable. This invention addresses the issue in existing flame-retardant power cable structures where the internal insulation layer softens upon heating, causing localized water molecules or hydrates in the cable to bulge, deform, or crack, and drip, resulting in weakened or lost protective capabilities and poor performance.

[0004] The technical solution of the present invention to achieve the above objectives is as follows: a Class B flame-retardant low-voltage cable, comprising multiple conductor cores and a first flame-retardant sheath, each conductor core being wrapped with an insulation layer, the insulation layer being wrapped with a second flame-retardant sheath, a foaming layer being filled between the second flame-retardant sheath and the first flame-retardant sheath, the first flame-retardant sheath being wrapped with an armor layer, the armor layer being wrapped with a third flame-retardant sheath, and a tensile reinforcement component being provided on the outside of the third flame-retardant sheath; The tensile reinforcement component includes a fourth flame-retardant sheath, which is fitted onto the outer wall of the third flame-retardant sheath. The inner wall of the fourth flame-retardant sheath has a support cavity arranged in a circular array. Tensile ropes are inserted into the support cavities and are attached to the outer wall of the third flame-retardant sheath. Multiple limiting strips are provided on the inner wall of the support cavity, and one end of each limiting strip is movably attached to the outer wall of the tensile rope.

[0005] Preferably, the armor layer is composed of several woven galvanized wires connected together.

[0006] Preferably, the foamed layer is made of an intumescent flame-retardant material, and the foamed layer can expand at high temperatures to form a porous carbonized layer.

[0007] Preferably, the first flame-retardant sheath, the second flame-retardant sheath, the third flame-retardant sheath, the fourth flame-retardant sheath, and the plurality of limiting strips are all made of halogen-free low-smoke flame-retardant polyolefin material; Preferably, the oxygen index of the first flame-retardant sheath, the second flame-retardant sheath, the third flame-retardant sheath, the fourth flame-retardant sheath, and the plurality of limiting strips is not less than 38.

[0008] Preferably, the first flame-retardant sheath is formed by wrapping halogen-free low-smoke flame-retardant tape, and is used to twist and fix multiple wire cores wrapped with the second flame-retardant sheath into conductor wire cores.

[0009] Preferably, the tensile rope is made of glass fiber reinforced plastic material.

[0010] The B1-grade flame-retardant low-voltage cable manufactured using the technical solution of this invention adopts a multi-layer flame-retardant structure consisting of a second flame-retardant sheath, a first flame-retardant sheath, and a third flame-retardant sheath, combined with an intumescent foam layer. When the outer sheath is exposed to fire, it forms a shell, creating a heat-insulating and oxygen-barrier protective layer that prevents molten droplets. The internal hydroxide flame retardant absorbs heat and decomposes, releasing water vapor, effectively cooling and diluting oxygen. The foam layer expands rapidly at high temperatures, forming a dense and thick carbonized layer that physically blocks the channels of flames and hot airflow, achieving suffocation fire suppression and preventing heat conduction to the interior, thereby achieving the B1-grade flame-retardant standard and reducing the risk of flames spreading along the cable. Attached Figure Description

[0011] Figure 1 This is a three-dimensional structural diagram of a B1-grade flame-retardant low-voltage cable according to the present invention.

[0012] Figure 2 This is a schematic diagram of the main structure of a B1-grade flame-retardant low-voltage cable according to the present invention.

[0013] In the diagram: 1. Conductor core, 2. First flame-retardant sheath, 3. Limiting strip, 4. Insulation layer, 5. Second flame-retardant sheath, 6. Foaming layer, 7. Armoring layer, 8. Third flame-retardant sheath, 9. Fourth flame-retardant sheath, 10. Support cavity, 11. Tension rope. Detailed Implementation

[0014] The present invention will now be described in detail with reference to the accompanying drawings, such as... Figure 1-2 As shown, a B1-grade flame-retardant low-voltage cable.

[0015] Those skilled in the art can connect the components in this case sequentially. The specific connection and operation sequence should refer to the working principle described below. The detailed connection methods are well-known technologies in the field. The working principle and process are mainly described below.

[0016] Example: A B1-grade flame-retardant low-voltage cable includes multiple conductor cores 1 and a first flame-retardant sheath 2. Each conductor core 1 is wrapped with an insulation layer 4. The insulation layer 4 is wrapped with a second flame-retardant sheath 5. A foam layer 6 is filled between the second flame-retardant sheath 5 and the first flame-retardant sheath 2. The first flame-retardant sheath 2 is wrapped with an armor layer 7. The armor layer 7 is wrapped with a third flame-retardant sheath 8. Tensile reinforcement components are provided on the outside of the third flame-retardant sheath 8. As a preferred and further option, the first flame-retardant sheath 2 is formed by wrapping flame-retardant tape, and is used to twist and fix multiple wire cores wrapped with the second flame-retardant sheath 5 into conductor wire core 1. It should be noted that the first flame-retardant sheath 2 is made into a flame-retardant tape, and multiple wire cores that have been wrapped in the second flame-retardant sheath 5 are twisted into a cable and bundled and fixed to form a round cable core. Multiple conductor cores 1 are responsible for transmitting electrical energy. The insulation layer 4 is wrapped around the outside of the conductor cores 1 to ensure electrical isolation between multiple conductor cores 1 and between conductor cores 1 and ground, and to prevent short circuits. Specifically, the tensile reinforcement component includes a fourth flame-retardant sheath 9, which is fitted onto the outer wall of the third flame-retardant sheath 8. The inner wall of the fourth flame-retardant sheath 9 has a support cavity 10 arranged in a circular array. A tensile rope 11 is inserted into the support cavity 10 and is attached to the outer wall of the third flame-retardant sheath 8. Multiple limiting strips 3 are provided on the inner wall of the support cavity 10, and one end of each limiting strip 3 is movably attached to the outer wall of the tensile rope 11. It should be noted that, as a preferred and further option, the tensile rope 11 is made of glass fiber reinforced plastic material, and the limiting strip 3 is made of high-strength and lightweight glass fiber reinforced plastic, which has tensile strength and corrosion resistance. It mainly bears the axial tensile force on the cable during laying, suspension or long-term operation, and prevents the sheath from being stretched and deformed or the internal structure from being damaged. The support cavity 10 is used to accommodate the tensile rope 11. By using multiple limiting strips 3 to prevent the tensile rope 11 from moving radially in the support cavity 10, it ensures that the tensile rope 11 is firmly positioned and closely attached to the third flame-retardant sheath 8, so that the tensile force is effectively transmitted and dispersed. At the same time, it prevents the tensile rope from moving or twisting in the cavity, optimizes the mechanical structure, and integrates the tensile function into the fourth flame-retardant sheath 9, making the cable structure more compact and round, with a better appearance, and easier to install and lay. As a preferred and further option, the first flame-retardant sheath 2, the second flame-retardant sheath 5, the third flame-retardant sheath 8, the fourth flame-retardant sheath 9 and the multiple limiting strips 3 are all made of halogen-free flame-retardant polyolefin material. As a preferred and further option, the oxygen index of the first flame-retardant sheath 2, the second flame-retardant sheath 5, the third flame-retardant sheath 8, the fourth flame-retardant sheath 9 and the multiple limiting strips 3 is not less than 38. It should be noted that the first flame-retardant sheath 2, the second flame-retardant sheath 5, the third flame-retardant sheath 8, the fourth flame-retardant sheath 9, and the multiple limiting strips 3 are made of halogen-free, low-smoke flame-retardant polyolefin material. By adding inorganic flame retardants magnesium hydroxide and aluminum hydroxide, their flame-retardant ability and synergistic flame-retardant ability are improved. Their oxygen index is not less than 38. In the event of a fire, the hydroxides absorb heat from the outside environment and decompose into water and metal oxides at high temperatures. This not only lowers the outside temperature, but the water produced further cools the cable and blocks outside oxygen. Simultaneously, the cable sheath forms a crust after a fire, and the flame-retardant material forms a heat-insulating layer to achieve heat insulation and oxygen isolation, further preventing the spread of flames, forming a protective layer, and preventing burning materials from dripping. As a preferred and further option, the foamed layer 6 is made of an intumescent flame-retardant material, and the foamed layer 6 can expand at high temperatures to form a porous carbonized layer. It should be noted that, in order to prevent further ignition of external combustibles, the foam layer 6 is made of intumescent flame retardant material. Under normal conditions, it is used to fill gaps, make the cable round and improve its flexibility. When exposed to fire, the foam layer 6 expands rapidly at high temperature to form a hard, porous carbonized layer that is dozens of times thicker than the original layer. This blocks the channels of flame and hot air flow, isolates the oxygen supply, suffocates and extinguishes the flame, and significantly blocks external high temperatures. As a preferred and further option, the armor layer 7 is made of several braided galvanized wires connected together; It should be noted that the armor layer 7 provides radial compressive strength, protecting the internal structure of the cable from external mechanical pressure, impact, and crushing, such as soil pressure during direct burial, construction misoperation, and vehicle crushing, to avoid damage to the internal structure of the cable. As a preferred and further option, the shielding layer 3 is a copper wire braided shielding layer or an aluminum-plastic composite tape shielding layer.

[0017] The above technical solutions only embody the preferred technical solutions of the present invention. Any modifications that may be made by those skilled in the art to certain parts thereof embody the principles of the present invention and fall within the protection scope of the present invention.

Claims

1. A B1-grade flame-retardant low-voltage cable, characterized in that, It includes multiple conductor cores (1) and a first flame-retardant sheath (2). Each conductor core (1) is wrapped with an insulation layer (4). The insulation layer (4) is wrapped with a second flame-retardant sheath (5). A foam layer (6) is filled between the second flame-retardant sheath (5) and the first flame-retardant sheath (2). The first flame-retardant sheath (2) is wrapped with an armor layer (7). The armor layer (7) is wrapped with a third flame-retardant sheath (8). The third flame-retardant sheath (8) is provided with tensile reinforcement components on its exterior. The tensile reinforcement component includes a fourth flame-retardant sheath (9), which is fitted onto the outer wall of the third flame-retardant sheath (8). The inner wall of the fourth flame-retardant sheath (9) is provided with a support cavity (10) in a circular array. A tensile rope (11) is inserted into the support cavity (10). The tensile rope (11) is attached to the outer wall of the third flame-retardant sheath (8). A plurality of limiting strips (3) are provided on the inner wall of the support cavity (10). One end of each of the limiting strips (3) is movably attached to the outer wall of the tensile rope (11).

2. The B1-grade flame-retardant low-voltage cable according to claim 1, characterized in that, The armor layer (7) is made of several woven galvanized wires connected together.

3. The B1-grade flame-retardant low-voltage cable according to claim 1, characterized in that, The foamed layer (6) is made of an intumescent flame retardant material, and the foamed layer (6) can expand at high temperature to form a porous carbonized layer.

4. A B1-grade flame-retardant low-voltage cable according to claim 1, characterized in that, The first flame-retardant sheath (2), the second flame-retardant sheath (5), the third flame-retardant sheath (8), the fourth flame-retardant sheath (9) and the multiple limiting strips (3) are all made of halogen-free low-smoke flame-retardant polyolefin material.

5. A B1-grade flame-retardant low-voltage cable according to claim 1, characterized in that, The oxygen index of the first flame-retardant sheath (2), the second flame-retardant sheath (5), the third flame-retardant sheath (8), the fourth flame-retardant sheath (9), and the plurality of limiting strips (3) is not less than 38.

6. A B1-grade flame-retardant low-voltage cable according to claim 1, characterized in that, The first flame-retardant sheath (2) is formed by wrapping halogen-free low-smoke flame-retardant strip material, and is used to twist and fix multiple wire cores wrapped with the second flame-retardant sheath (5) into conductor wire cores (1).

7. A B1-grade flame-retardant low-voltage cable according to claim 1, characterized in that, The tensile rope (11) is made of glass fiber reinforced plastic material.

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