Low-smoke halogen-free crosslinked polyethylene sheath flame-retardant cable

Abstract

The utility model discloses a low-smoke halogen-free crosslinked polyethylene sheath flame-retardant cable, which comprises a cable core, a composite flame-retardant layer is arranged outside the cable core, the composite flame-retardant layer is composed of a high-crosslinking high-temperature-resistant layer, a crosslinking water-producing flame-retardant layer and a flame-retardant outer layer, a composite shock-resistant layer is arranged outside the composite flame-retardant layer, and the flame-retardant outer layer is composed of a high-crosslinking high-temperature-resistant layer, a crosslinking water-producing flame-retardant layer and a flame-retardant outer layer. The composite anti-seismic layer is composed of a flexible buffer layer, a fiber reinforcement layer and an elastic shock absorption layer, and a low-smoke halogen-free flame-retardant protective sleeve is arranged outside the composite anti-seismic layer, so that the problem that fire rescue and personnel evacuation work can be hindered by smoke generated during combustion of halogen contained in the flame-retardant cable is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of cables, in particular to a low-smoke, halogen-free, cross-linked polyethylene sheathed flame-retardant cable. Background Art

[0002] Flame-retardant cables refer to cables that, under specific test conditions, after the sample is burned, the fire source is removed, the spread of the flame is limited to a limited range, and the residual flame or residual burning can be extinguished within a limited time. Its fundamental characteristic is that although the cable may be burned in a fire and cannot operate normally, it can effectively prevent the further spread of the fire, thereby protecting other equipment and reducing losses. Flame-retardant cables use materials with good flame-retardant properties as conductors, insulation layers and sheaths. These materials are usually added with additives such as flame retardants and antioxidants to improve their flame retardant properties and ensure that the materials are not easy to burn or burn slowly when a fire occurs.

[0003] For example, the Chinese authorized patent "A high-temperature resistant flame-retardant cable" with announcement number CN211350177U includes nitrile polyvinyl chloride rubber, a nylon rope is arranged inside the nitrile polyvinyl chloride rubber, an epoxy resin layer is arranged on the inner surface of the nitrile polyvinyl chloride rubber, a steel mesh layer is arranged on the inner surface of the epoxy resin layer by weaving, a chlorosulfonated polyethylene rubber is arranged on the inner surface of the steel mesh layer, and a nylon woven mesh is arranged on the inner surface of the chlorosulfonated polyethylene rubber; the nylon rope arranged inside the nitrile polyvinyl chloride rubber makes it easier to strengthen the structure of the nitrile polyvinyl chloride rubber through the nylon rope, thereby increasing the tensile strength of the nitrile polyvinyl chloride rubber, and at the same time, an epoxy resin layer is arranged between the nitrile polyvinyl chloride rubber and the steel mesh layer.

[0004] Although the above-mentioned prior art has certain flame retardant properties, the flame retardant material contains halogen. The large amount of smoke generated when the halogen-containing cable burns will seriously hinder fire rescue and personnel evacuation. The smoke reduces visibility, making it difficult for rescuers to find the trapped, and also increases the difficulty for the trapped to escape. Therefore, it does not meet the existing needs. In this regard, we propose a low-smoke halogen-free cross-linked polyethylene sheathed flame retardant cable. Utility Model Content

[0005] The utility model aims to provide a low-smoke halogen-free cross-linked polyethylene sheathed flame-retardant cable to solve the problem in the above background technology that the smoke generated by the halogen contained in the flame-retardant cable during combustion will hinder fire rescue and personnel evacuation.

[0006] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a low-smoke halogen-free cross-linked polyethylene sheathed flame-retardant cable, comprising a cable core, a composite flame-retardant layer is arranged on the outside of the cable core, the composite flame-retardant layer is composed of a high-cross-linked high-temperature resistant layer, a cross-linked water-producing flame-retardant layer and a flame-retardant outer layer, a composite seismic-resistant layer is arranged on the outside of the composite flame-retardant layer, the composite seismic-resistant layer is composed of a flexible buffer layer, a fiber reinforced layer and an elastic shock-absorbing layer, and a low-smoke halogen-free flame-retardant protective sleeve is arranged on the outside of the composite seismic-resistant layer.

[0007] Preferably, the cross-linked water-producing flame-retardant layer is arranged on the outer wall of the highly cross-linked high-temperature resistant layer, and the flame-retardant outer layer is arranged on the outer wall of the cross-linked water-producing flame-retardant layer. The highly cross-linked high-temperature resistant layer, the cross-linked water-producing flame-retardant layer and the flame-retardant outer layer are extruded separately and coated on the cable core at the same time by multi-layer co-extrusion equipment to form an integrated composite flame-retardant layer.

[0008] Preferably, the fiber reinforced layer is wrapped on the outer wall of the flexible buffer layer in a mesh shape by weaving or winding, and the elastic shock-absorbing layer is wrapped on the outer wall of the fiber reinforced layer by hot pressing equipment.

[0009] Preferably, three first wire cores distributed in an annular manner are provided inside the cable core, and second wire cores are provided between adjacent first wire cores, and the diameter of the second wire cores is smaller than that of the first wire cores.

[0010] Preferably, the first wire core and the second wire core are both composed of a conductor and an insulating layer, the conductor is formed by twisting a plurality of metal wires together, and the insulating layer is extruded and wrapped around the outside of the conductor.

[0011] Preferably, a filler is injected into the gap between the first wire core and the second wire core.

[0012] Preferably, the low-smoke halogen-free flame-retardant protective sleeve is wrapped around the outside of the composite earthquake-resistant layer by means of a heating extrusion device.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] 1. The utility model is provided with a composite flame retardant layer, which is composed of a high-cross-linked high-temperature resistant layer, a cross-linked water-producing flame retardant layer and a flame retardant outer layer. The use of halogen-free flame retardants ensures that the cable will not release toxic halogen-containing gases and a large amount of smoke when burning, which is conducive to personnel evacuation and fire fighting. The inner layer material with a high degree of cross-linking can withstand high temperatures and maintain structural stability. At the same time, the good combination between the layers improves the overall mechanical strength of the cable. The entire composite flame retardant layer is made of halogen-free, low-smoke, non-toxic materials, meets environmental protection requirements, and is harmless to human health. The excellent flame retardant and heat-resistant properties can reduce the damage to the cable caused by fire or high temperature environment, thereby extending the service life of the cable.

[0015] 2. The utility model is provided with a composite seismic-resistant layer, which is composed of a flexible buffer layer, a fiber reinforced layer and an elastic shock-absorbing layer. Through the triple protection of outer layer shock absorption, middle layer reinforcement and inner layer buffering, it ensures that the conductor and insulation layer inside the cable can remain intact under strong vibration, reduces cable damage and maintenance needs caused by vibration, thereby reducing maintenance costs and extending the overall service life of the cable. The composite seismic-resistant layer is made of weather-resistant materials, so that the cable can maintain stable seismic performance in harsh natural environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a three-dimensional diagram of the utility model;

[0017] Figure 2 It is a schematic diagram of the internal structure of the utility model;

[0018] Figure 3 This is a schematic diagram of the composite flame retardant layer structure of the utility model;

[0019] Figure 4 It is a schematic diagram of the composite earthquake-resistant layer structure of the utility model.

[0020] In the figure: 1. Cable core; 2. Composite flame retardant layer; 21. High cross-linked high temperature resistant layer; 22. Cross-linked water-producing flame retardant layer; 23. Flame retardant outer layer; 3. Composite seismic resistant layer; 31. Flexible buffer layer; 32. Fiber reinforced layer; 33. Elastic shock absorbing layer; 4. Low smoke halogen-free flame retardant protective sleeve; 5. First core; 6. Second core; 7. Filler; 8. Conductor; 9. Insulation layer. DETAILED DESCRIPTION

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0022] See also Figure 1-4 The utility model provides an embodiment: a low-smoke halogen-free cross-linked polyethylene sheathed flame-retardant cable, comprising a cable core 1, a composite flame-retardant layer 2 is arranged on the outside of the cable core 1, the composite flame-retardant layer 2 is composed of a high-cross-linked high-temperature resistant layer 21, a cross-linked water-producing flame-retardant layer 22 and a flame-retardant outer layer 23, a composite seismic-resistant layer 3 is arranged on the outside of the composite flame-retardant layer 2, the composite seismic-resistant layer 3 is composed of a flexible buffer layer 31, a fiber reinforced layer 32 and an elastic shock-absorbing layer 33, a low-smoke halogen-free flame-retardant protective sleeve 4 is arranged on the outside of the composite seismic-resistant layer 3, the low-smoke halogen-free flame-retardant protective sleeve 4 is wrapped on the outside of the composite seismic-resistant layer 3 by a heating and extrusion device, and a filler 7 is injected into the gap between the first core 5 and the second core 6.

[0023] The multi-layer composite flame retardant structure can play its own flame retardant advantages in different temperature ranges, forming multiple barriers to effectively prevent the spread of flames. The multi-layer composite seismic structure can effectively absorb and disperse vibration energy, reducing the risk of cable damage under external forces such as earthquakes and mechanical vibrations. The low-smoke halogen-free flame retardant protective cover 4 can significantly reduce smoke generation in extreme cases such as fire, and does not contain harmful substances such as halogens, which is friendly to personnel health and the environment.

[0024] See also Figure 2 and Figure 3 The cross-linked water-generating flame-retardant layer 22 is arranged on the outer wall of the high cross-linked high temperature resistant layer 21, and the flame-retardant outer layer 23 is arranged on the outer wall of the cross-linked water-generating flame-retardant layer 22. The high cross-linked high temperature resistant layer 21, the cross-linked water-generating flame-retardant layer 22 and the flame-retardant outer layer 23 are extruded separately and coated on the cable core 1 at the same time by a multi-layer co-extrusion device to form an integrated composite flame-retardant layer 2. The high cross-linked high temperature resistant layer 21 adopts a polyolefin material with a high cross-linking degree. By increasing the content of silane and peroxide, the layer has extremely high heat resistance and tensile strength. As the core protective layer inside the cable, it can withstand the high temperature generated by the conductor and maintain the integrity of the structure in extreme cases such as short circuits, preventing the short circuit inside the cable from causing a larger fire; the cross-linked water-generating flame-retardant layer 22 adopts a mixture of cross-linked polyolefin and a small amount of silane cross-linking agent, peroxide cross-linking catalyst and water-generating agent. The cross-linking degree of this layer is moderate, and it can cross-link naturally in the absence of external moisture, while providing the inner layer with the moisture required for cross-linking. This layer not only has flame retardant properties, but also can produce water vapor during the combustion process, further diluting the combustible gas. At the same time, its moderate cross-linking degree increases the toughness and deformation resistance of the material. The flame retardant outer layer 23 uses halogen-free flame retardant polyolefin as the main base material, and adds high-efficiency low-smoke halogen-free flame retardant (such as aluminum hydroxide and magnesium hydroxide). It can decompose and produce water vapor at high temperatures to dilute the concentration of combustible gases, and at the same time form a dense carbon layer to play a role in heat insulation and oxygen isolation. As the first line of defense of the cable, it directly faces the fire source and effectively prevents the spread of flames.

[0025] See also Figure 2 and Figure 4The fiber reinforcement layer 32 is wrapped in a mesh on the outer wall of the flexible buffer layer 31 by weaving or winding, and the elastic shock-absorbing layer 33 is wrapped on the outer wall of the fiber reinforcement layer 32 by hot pressing equipment. The flexible buffer layer 31 adopts low-density, high-energy-absorbing polyethylene foam, which can quickly deform and absorb a large amount of energy when compressed. As the last layer of protective barrier inside the cable, it provides soft support and buffering for the cable core, ensuring that the conductor and insulation layer inside the cable will not be directly impacted under strong vibration; the fiber reinforcement layer 32 adopts Kevlar fiber, which is formed into a mesh or layered structure by weaving or winding, enhancing the overall structural strength of the cable and preventing the cable from breaking or deforming under strong vibration. At the same time, the fiber layer can also provide a certain damping effect to further reduce vibration transmission; the elastic shock-absorbing layer 33 adopts silicone material, which has good elastic recovery ability and certain damping performance, and can effectively absorb energy and reduce vibration transmission when impacted by external force. As the first layer of anti-seismic barrier of the cable, it directly faces the vibration source in the external environment, such as seismic waves, mechanical vibrations, etc., and reduces the impact of vibration through the elastic deformation of the material.

[0026] See also Figure 1 and Figure 2 The cable core 1 is provided with three first cores 5 distributed in an annular pattern, and a second core 6 is provided between adjacent first cores 5. The diameter of the second core 6 is smaller than that of the first core 5. The first core 5 and the second core 6 are both composed of a conductor 8 and an insulating layer 9. The conductor 8 is twisted together by a plurality of metal wires, and the insulating layer 9 is extruded and wrapped on the outside of the conductor 8. The conductor 8 uses high-purity oxygen-free copper as the core conductor to ensure excellent electrical conductivity and mechanical strength. Oxygen-free copper not only has high conductivity, but also has strong antioxidant ability, which is conducive to the long-term stable operation of the cable. The inner insulating layer 9 uses cross-linked polyethylene as the insulating material, which is a halogen-free and high-temperature resistant polymer, and has excellent electrical insulation and physical and mechanical properties, and can maintain stable electrical properties in high temperature environments.

[0027] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

Claims

1. A low-smoke, halogen-free, cross-linked polyethylene sheathed flame-retardant cable, comprising a cable core (1), characterized in that: A composite flame retardant layer (2) is arranged outside the cable core (1), the composite flame retardant layer (2) is composed of a highly cross-linked high temperature resistant layer (21), a cross-linked water-generating flame retardant layer (22) and a flame retardant outer layer (23), a composite earthquake-resistant layer (3) is arranged outside the composite flame retardant layer (2), the composite earthquake-resistant layer (3) is composed of a flexible buffer layer (31), a fiber reinforcement layer (32) and an elastic shock-absorbing layer (33), and a low-smoke halogen-free flame retardant protective sleeve (4) is arranged outside the composite earthquake-resistant layer (3).

2. The low-smoke zero-halogen cross-linked polyethylene sheathed flame-retardant cable according to claim 1, characterized in that: The cross-linked water-generating flame-retardant layer (22) is arranged on the outer wall of the highly cross-linked high-temperature resistant layer (21), and the flame-retardant outer layer (23) is arranged on the outer wall of the cross-linked water-generating flame-retardant layer (22). The highly cross-linked high-temperature resistant layer (21), the cross-linked water-generating flame-retardant layer (22), and the flame-retardant outer layer (23) are extruded separately and simultaneously coated on the cable core (1) using a multi-layer co-extrusion device to form an integrated composite flame-retardant layer (2).

3. The low-smoke zero-halogen cross-linked polyethylene sheathed flame-retardant cable according to claim 1, characterized in that: The fiber reinforced layer (32) is wrapped in a mesh shape on the outer wall of the flexible buffer layer (31) by weaving or winding, and the elastic shock absorbing layer (33) is wrapped on the outer wall of the fiber reinforced layer (32) by hot pressing equipment.

4. The low-smoke zero-halogen cross-linked polyethylene sheathed flame-retardant cable according to claim 1, characterized in that: Three first wire cores (5) distributed in an annular manner are arranged inside the cable core (1), and second wire cores (6) are arranged between adjacent first wire cores (5), wherein the diameter of the second wire cores (6) is smaller than that of the first wire cores (5).

5. The low-smoke zero-halogen cross-linked polyethylene sheathed flame-retardant cable according to claim 4, characterized in that: The first wire core (5) and the second wire core (6) are both composed of a conductor (8) and an insulating layer (9); the conductor (8) is composed of a plurality of metal wires twisted together; and the insulating layer (9) is extruded and wrapped around the outside of the conductor (8).

6. The low-smoke zero-halogen cross-linked polyethylene sheathed flame-retardant cable according to claim 4, characterized in that: A filler (7) is injected into the gap between the first wire core (5) and the second wire core (6).

7. The low-smoke zero-halogen cross-linked polyethylene sheathed flame-retardant cable according to claim 1, characterized in that: The low-smoke halogen-free flame-retardant protective sleeve (4) is wrapped around the outside of the composite anti-seismic layer (3) by means of a heating extrusion device.

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