A flame retardant, fire resistant and lightning protection optical cable

Abstract

The utility model provides a flame-retardant, fire-resistant and lightning-proof optical cable, comprising a layer-twisted cable core and a protective layer wrapped around the outside of the layer-twisted cable core; the layer-twisted cable core comprises a central reinforcement member arranged in the center and a plurality of fire-resistant optical units and filling units surrounding the outside of the central reinforcement member; the protective layer comprises a water-blocking tape, an inner sheath, a fire-retardant coating layer, an electrophobic layer and an outer sheath arranged in sequence from the inside to the outside, and the gap between the layer-twisted cable core and the inner sheath is filled with a cable core dry water-blocking yarn.

Description

Technical Field

[0001] The utility model relates to the technical field related to optical communication technology, and more precisely to a flame-retardant, fire-resistant and lightning-proof optical cable. Background Art

[0002] Optical communication networks are an indispensable infrastructure in current production and life. Optical cables are the foundation and key component of optical communication networks, providing basic support for optical communication ecosystems such as telephone communications, Internet access, and wireless communications. The stability of optical cables is crucial to the normal operation of optical communication networks.

[0003] At present, when laying optical communication networks, the commonly used optical cables are traditional conventional optical cables. Conventional optical cables are generally composed of optical fibers, fiber sleeves, casings, fillers, water-blocking grease, metal reinforcements and sheaths, which can meet the use requirements in general urban environments. However, the requirements of flame retardancy, fire resistance and lightning protection are not fully considered in the design of conventional optical cables. When extreme situations such as fire or lightning strike occur, the flammability and conductivity of conventional optical cable materials will aggravate the accident losses.

[0004] In order to solve the above problems, optical cables with flame retardant and fire resistant functions and optical cables with lightning protection functions have been developed in this field to meet the use requirements of special scenarios such as power, railways, tunnels, mines and data centers. The existing optical cables with flame retardant and fire resistant functions adopt a PBT loose tube layer twisted structure, and a flame retardant layer and a heat insulation layer are added to the outside of the PBT loose tube twisted cable core to achieve flame retardant and fire resistant functions. The main application scenarios of flame retardant and fire resistant optical cables cover various critical environments that require fire protection and communication connectivity, such as internal communications in buildings, data centers, petrochemical and chemical plants, subways and tunnel systems. Existing optical cables with lightning protection functions use non-metallic materials, insulating materials and shielding layer technology to reduce the risk of electrical breakdown caused by lightning. Common types of optical cables with lightning protection functions include OPGW (optical ground wire composite optical cable), ADSS (all-dielectric self-supporting optical cable) and all-dielectric reinforced optical cable. The structural composition of the all-dielectric optical cable does not contain metal materials, so it is suitable for electromagnetic interference environments and areas with frequent lightning. OPGW is a fiber optic communication cable for power transmission lines, which combines optical communication and power transmission functions, but the special properties of its optical fiber components and composite structure make it more expensive to manufacture and install. The outer sheath of ADSS cable is mainly composed of insulating materials, so it usually does not have high mechanical strength like traditional metal-reinforced optical cables, which makes it more susceptible to damage from external mechanical pressure or extrusion.

[0005] However, the fire resistance of existing flame-retardant and fire-resistant optical cables is usually limited. The external flame-retardant sheath cannot maintain a stable shape for a long time and will melt or deform at high temperatures, thereby damaging the internal optical fiber and causing communication interruption. Existing flame-retardant and fire-resistant optical cables will produce toxic gases and thick smoke when burning, endangering the lives of people in the installation space, and a large amount of smoke will interfere with people's vision and affect evacuation and fire fighting. In addition, the flame-retardant and fire-resistant optical cables have metal materials inside and no lightning protection layer, lacking lightning protection capabilities. They may be struck by lightning during frequent thunderstorms in summer, thus posing serious safety hazards to the operation of optical cable lines.

[0006] Existing lightning-proof optical cables can only reduce the probability of being struck by lightning. Once struck by lightning, the communication equipment connected to the optical cables will be damaged. The existing lightning-proof optical cables do not contain metal materials in their structure, so they are insufficiently strong and difficult to install over long distances. Optical cables reinforced with non-metallic armor cannot meet the needs of complex terrain environments due to their size, weight, bending radius, etc.

[0007] In summary, this field lacks optical cables that have flame retardant, fire resistant and lightning protection functions, and cannot meet the higher requirements of modern optical network communications for security, reliability and transmission performance. Utility Model Content

[0008] In view of this, the purpose of the present invention is to provide a flame retardant, fire resistant and lightning protection optical cable, which has the functions of flame retardant, fire resistant and lightning protection.

[0009] In order to achieve the above-mentioned purpose, the utility model provides a flame-retardant, fire-resistant and lightning-proof optical cable, comprising a twisted cable core and a protective layer wrapped around the outside of the twisted cable core; the twisted cable core comprises a central reinforcement member arranged in the center and a plurality of fire-resistant optical units and filling units surrounding the outside of the central reinforcement member; the protective layer comprises a water-blocking tape, an inner sheath, a fire-retardant coating layer, an electrophobic layer and an outer sheath arranged in sequence from the inside to the outside, and the gap between the twisted cable core and the inner sheath is filled with cable core dry water-blocking yarn.

[0010] Preferably, the electrophobic layer is partially embedded in the outer sheath, and the outer protrusion of the electrophobic layer embedded in the outer sheath is tangent to the outer surface of the outer sheath, and the electrophobic layer and the outer sheath are tightly wrapped together on the outside of the fire retardant coating layer.

[0011] Preferably, the fire-resistant optical unit comprises a plurality of optical fibers, a loose tube wrapped around the plurality of optical fibers, and a fire-resistant layer wrapped around the loose tube, and the gaps between the plurality of optical fibers and the loose tube are filled with dry water-blocking yarn of the optical unit.

[0012] Preferably, the fire-resistant layer is made of mica tape material.

[0013] Preferably, the loose tube is made of PBT material.

[0014] Preferably, the inner sheath is made of ceramic low-smoke halogen-free flame-retardant polyolefin refractory material.

[0015] Preferably, the fire retardant coating layer adopts solvent-free halogen-free water-based environmentally friendly fire retardant coating.

[0016] Preferably, the electrophobic layer is made of a lightning protection metal mesh.

[0017] Preferably, the outer sheath is made of low-smoke halogen-free polyolefin material.

[0018] Compared with the prior art, the flame retardant, fire-resistant and lightning-proof optical cable disclosed by the utility model has the following advantages: the flame retardant, fire-resistant and lightning-proof optical cable has both flame retardant, fire-resistant and lightning-proof functions, which effectively improves the safety of the optical cable; the flame retardant, fire-resistant and lightning-proof optical cable adopts a fully dry structure and is not filled with ointment, thereby avoiding the combustion-supporting effect of the ointment on the optical cable and reducing smoke during combustion; the flame retardant, fire-resistant and lightning-proof optical cable adopts an arched lightning protection metal mesh, which has better lightning protection effect and can improve the tensile strength of the optical cable; the fire-resistant layer of the flame retardant, fire-resistant and lightning-proof optical cable covers the outside of the loose sleeve of the optical fiber, reduces the internal space of the fire-resistant optical unit, improves the stability of the fire-resistant optical unit after combustion, and ensures that the optical fiber maintains transmission performance and structural integrity in a high temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] like Figure 1 Shown is a cross-sectional schematic diagram of a flame-retardant, fire-resistant and lightning-proof optical cable of the utility model. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] like Figure 1As shown, the present application is a flame-retardant, fire-resistant and lightning-proof optical cable, comprising a layer-twisted cable core 1 and a protective layer 2 wrapped around the outside of the layer-twisted cable core 1; the layer-twisted cable core 1 comprises a central reinforcement 11 arranged in the center and a plurality of fire-resistant optical units 12 and a filling unit 13 surrounding the outside of the central reinforcement 11; the protective layer 2 comprises a water-blocking tape 21, an inner sheath 22, a fire-retardant coating layer 23, an electrophobic layer 24 and an outer sheath 25 arranged in sequence from the inside to the outside, and the gap between the layer-twisted cable core 1 and the inner sheath 22 is filled with a cable core dry water-blocking yarn 211. The fire-resistant optical unit 12 itself has flame-retardant and fire-resistant functions, and can maintain the normal operation of the internal optical fiber after the protective layer 2 is damaged. The filling unit 13 is provided to make the cross-section of the layer-twisted cable core 1 more rounded. The layer-twisted cable core 1 and the inner sheath 22 are filled with a cable core dry water-blocking yarn 211, which replaces the traditional filling ointment, can avoid the combustion-supporting effect of the ointment, and can also avoid the generation of a large amount of smoke due to the burning of the ointment. The flame retardant, fire resistant and lightning protection optical cable has both flame retardant, fire resistant and lightning protection functions, effectively improves the safety of the optical cable, and can meet the higher requirements of modern optical network communications for safety, reliability and transmission performance.

[0023] Among them, the electrophobic layer 24 is partially embedded in the outer sheath 25, and the outer protrusion of the electrophobic layer 24 embedded in the outer sheath 25 is tangent to the outer surface of the outer sheath 25, and the electrophobic layer 24 and the outer sheath 25 are tightly wrapped together on the outside of the fire retardant coating layer 23. The protrusion of the electrophobic layer 24 is exposed to the outside of the optical cable. In a thunderstorm weather environment, under the action of the strong electric field of the natural environment, the lightning protection metal mesh will generate an induced electric field to form an induced current, and the lightning energy will dissipate on the surface of the micro-grid metal to prevent the current from invading the cable core and causing electrical breakdown of the optical cable; in addition, the electrophobic layer 24 is embedded in the outer sheath 25, which can improve the overall tensile performance of the optical cable, which is conducive to improving the overall mechanical strength of the optical cable.

[0024] The fire-resistant optical unit 12 comprises a plurality of optical fibers 121, a loose tube 123 wrapped outside the plurality of optical fibers 121, and a fire-resistant layer 124 wrapped outside the loose tube 123. The light unit dry water-blocking yarn 122 is filled in the gap between the plurality of optical fibers 121 and the loose tube 123. The oil paste filled by the dry water-blocking yarn can avoid the combustion-supporting effect of the oil paste, and can avoid the generation of a large amount of smoke due to the burning of the oil paste. By wrapping the fire-resistant layer 124 outside the loose tube 123, the independent fire-resistant function of the optical unit is realized, the internal space of the fire-resistant optical unit is reduced, the stability of the fire-resistant optical unit after burning is improved, and the transmission performance and structural integrity of the optical fiber are guaranteed to be maintained under high temperature environment. The fire-resistant layer 124 preferably adopts mica tape material, and the mica tape is directly coated on the outside of the loose tube 123. After the optical cable is destroyed by the flame, the mica tape wrapping can delay the heat generated when the optical cable burns and transfer it to the loose tube, reducing the impact of the environment on the optical fiber.

[0025] The loose tube 123 is made of PBT material. When designing the optical cable, the number of the loose tube 123 in the cable core is reduced as much as possible to reduce the amount of combustibles in the optical cable structure.

[0026] Specifically, the central reinforcement 11 is preferably made of FRP non-metallic material, which has the characteristics of light weight, high strength and good corrosion resistance. The inner sheath 21 is preferably made of ceramic low-smoke halogen-free flame-retardant polyolefin refractory material. Based on the characteristics of ceramic materials, it will quickly harden and gradually ceramicize under flame conditions or at high temperatures above 500°C, forming a hard and dense ceramic shell oxygen-isolating layer, and isolating the flame from spreading inward. It can withstand continuous high temperatures of 1200°C to 1600°C, and is safe, environmentally friendly and non-toxic. It can improve the fire-resistant and heat-insulating effect, and is more environmentally friendly. The fire-retardant coating layer 23 uses cable fire-retardant coating, which is a solvent-free halogen-free water-based environmentally friendly fire-retardant coating that is resistant to moisture, freeze-thaw cycles, ultraviolet radiation and various oils and chemicals. It can be used as a protective coating for cables. After encountering fire, it decomposes internally and releases cooling gas, and carbonization is formed on the surface to slow down heat transfer, with a temperature resistance of up to 1000°C.

[0027] It is worth noting that when the required flame retardant and fire resistant grade is low, the flame retardant and fire resistant material in the optical cable can be adjusted and replaced according to the use and performance requirements. For example, the inner sheath 21 can use conventional flame retardant materials instead of ceramic polyolefin to reduce the cost of raw materials and processing. When the diameter of the central reinforcement member is required to be larger to meet the tension requirements of the optical cable, the sheath layer can be wrapped around the non-metallic central reinforcement member to increase the diameter.

[0028] The electrophobic layer 24 is made of a lightning-proof metal mesh, which is light and thin, with tiny surface grids and uniform openings, and has a good flow-conducting effect. As an excellent conductive medium, the electrophobic layer 24 can conduct current and remove static electricity. The lightning energy will dissipate on the micro-grid metal surface to protect the core component of the optical cable, the optical fiber.

[0029] The outer sheath 25 is made of crack-resistant, highly flame-retardant, low-smoke, halogen-free polyolefin material, which has good flame-retardant properties as well as good mechanical properties and environmental properties.

[0030] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flame retardant, fire resistant and lightning protection optical cable, characterized in that: It comprises a twisted cable core and a protective layer wrapped around the outside of the twisted cable core; the twisted cable core comprises a central reinforcement member arranged in the center and a plurality of fire-resistant light units and filling units surrounding the outside of the central reinforcement member; the protective layer comprises a water-blocking tape, an inner sheath, a fire-retardant coating layer, an electrophobic layer and an outer sheath arranged in sequence from the inside to the outside, and the gap between the twisted cable core and the inner sheath is filled with cable core dry water-blocking yarn.

2. The flame-retardant, fire-resistant and lightning-proof optical cable according to claim 1, characterized in that: The electrophobic layer is partially embedded in the outer sheath, and the outer protrusion of the electrophobic layer embedded in the outer sheath is tangent to the outer surface of the outer sheath. The electrophobic layer and the outer sheath are tightly wrapped together outside the fire retardant coating layer.

3. The flame-retardant, fire-resistant and lightning-proof optical cable according to claim 1, characterized in that: The fire-resistant optical unit comprises a plurality of optical fibers, a loose tube wrapped outside the plurality of optical fibers, and a fire-resistant layer wrapped outside the loose tube, and the gaps between the plurality of optical fibers and the loose tube are filled with optical unit dry water-blocking yarn.

4. The flame-retardant, fire-resistant and lightning-proof optical cable according to claim 3, characterized in that: The fire-resistant layer is made of mica tape material.

5. The flame-retardant, fire-resistant and lightning-proof optical cable according to claim 3, characterized in that: The loose tube is made of PBT material.

6. The flame-retardant, fire-resistant and lightning-proof optical cable according to claim 1, characterized in that: The inner sheath is made of ceramic low-smoke halogen-free flame-retardant polyolefin refractory material.

7. The flame-retardant, fire-resistant and lightning-proof optical cable according to claim 1, characterized in that: The fire retardant coating layer adopts solvent-free halogen-free water-based environmentally friendly fire retardant coating.

8. The flame-retardant, fire-resistant and lightning-proof optical cable according to claim 1, characterized in that: The electrophobic layer adopts a lightning protection metal mesh.

9. The flame-retardant, fire-resistant and lightning-proof optical cable according to claim 1, characterized in that: The outer sheath is made of low-smoke halogen-free polyolefin material.

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