Multi-tube for optical cables with flame retardancy

Abstract

The present invention discloses a multi-tube for an optical cable having flame retardancy, comprising: a plurality of inner tubes; an outer tube surrounding the plurality of inner tubes; and an outer flame retardant layer disposed on the outer surface of the outer tube.

Description

Technology Field

[0001] The present invention relates to a multi-tube for optical cables having flame retardancy. Background Technology

[0003] Ducts for protecting communication and power cables are installed in various environments and play an important role in protecting cables from external impacts and fire. In particular, Corrugated Optic Ducts (CODs) are frequently used inside buildings, underground facilities, and above-ground structures, so fire safety is considered an important factor.

[0004] However, conventional COD pipes lack sufficient flame-retardant performance, making them highly likely to emit toxic gases accompanied by rapid combustion in the event of a fire. Generally, COD pipes are manufactured from polymer plastics, which can combust rapidly above a certain temperature. In particular, while conventional flame retardants are typically applied to the surface, this method can lead to the loss of the protective layer or performance degradation at high temperatures. Furthermore, the combustion of conventional COD pipes generates high concentrations of smoke, which can impede visibility and hinder evacuation and rescue operations. Additionally, if used indoors or in enclosed spaces, the release of toxic gases poses a significant risk of increased casualties.

[0005] Although some COD pipes utilize a method of adding fire retardants (FR) to enhance flame retardant performance, existing fire retardants may degrade over time or decompose at high temperatures, making it difficult to guarantee long-term performance; furthermore, some fire retardants contain chemicals harmful to the environment and human health, which may limit their continued use.

[0006] Therefore, it is necessary to develop technology that can simultaneously improve the flame retardancy and low smoke resistance of COD pipes, and the application of new materials capable of overcoming the limitations of existing flame retardants is required. The problem to be solved

[0008] The present invention aims to provide a multi-tube for optical cables that has flame resistance capable of minimizing toxic gases in the event of a fire, reducing smoke generation, and maintaining long-term flame resistance performance by applying an FR-LSZH (Fire Resistant-Low Smoke Zero Halogen) flame-retardant layer to the outer and inner tubes of a COD tube.

[0009] Meanwhile, the technical problems to be solved by the present invention are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0011] An embodiment of the present invention is

[0012] Multiple internal tubes;

[0013] An outer casing surrounding a plurality of the above inner tubes; and

[0014] A flame-retardant layer disposed on the outer surface of the above exterior; comprising

[0015] It is possible to provide a multi-tube for optical cables that has flame retardancy.

[0016] In addition, embodiments of the present invention

[0017] The above exterior is molded into a corrogate shape,

[0018] It is possible to provide a multi-tube for optical cables that has flame retardancy.

[0019] In addition, embodiments of the present invention

[0020] The thickness of the above exterior and the thickness of the above exterior flame-retardant layer are the same.

[0021] It is possible to provide a multi-tube for optical cables that has flame retardancy.

[0022] In addition, embodiments of the present invention

[0023] At least one of the inner tube and the outer tube is

[0024] including high density polyethylene (HDPE),

[0025] It is possible to provide a multi-tube for optical cables that has flame retardancy.

[0026] In addition, embodiments of the present invention

[0027] The above exterior flame-retardant layer

[0028] Formed as FR-LSZH (Flame Retardancy-Low Smoke Zero Halogen), which minimizes smoke and minimizes the generation of halogen gases through the oxidation of magnesium hydroxide even when burned in strong flames during a fire,

[0029] It is possible to provide a multi-tube for optical cables that has flame retardancy.

[0030] In addition, embodiments of the present invention

[0031] A silicone layer further comprising a silicone layer disposed on the inner surface of the inner tube.

[0032] It is possible to provide a multi-tube for optical cables that has flame retardancy.

[0033] In addition, embodiments of the present invention

[0034] A traction line further comprising the inner tube of the above-mentioned inner tube

[0035] It is possible to provide a multi-tube for optical cables that has flame retardancy.

[0036] In addition, embodiments of the present invention

[0037] Appearance; and

[0038] A flame-retardant layer disposed on the outer surface of the above exterior; comprising

[0039] It is possible to provide a multi-tube for optical cables that has flame retardancy. Effects of the invention

[0041] According to an embodiment of the present invention, by applying a FR-LSZH (Fire Resistant-Low Smoke Zero Halogen) flame-retardant layer to the outer and inner tubes of a COD tube, it is possible to minimize toxic gases in the event of a fire, reduce smoke generation, and maintain long-term flame-retardant performance.

[0042] Meanwhile, the effects obtainable from the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art to which the present invention belongs from the description below. Brief explanation of the drawing

[0044] FIG. 1 is a perspective view showing a multi-tube for an optical cable having flame retardancy according to one embodiment of the present invention, and FIG. 2 is a side cross-sectional view illustrating a multi-tube for an optical cable having flame retardancy according to one embodiment of the present invention, and FIG. 3 is a side cross-sectional view illustrating a multitube for an optical cable having flame retardancy according to another embodiment of the present invention, and FIG. 4 is a side cross-sectional view illustrating a multitube for an optical cable having flame retardancy according to another embodiment of the present invention, and FIG. 5 is a side cross-sectional view illustrating a multi-tube for an optical cable having flame retardancy according to another embodiment of the present invention. Specific details for implementing the invention

[0045] Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be interpreted as being limited to the embodiments below. These embodiments are provided to more fully explain the present invention to those with average knowledge in the art. Accordingly, the shapes of the elements in the drawings have been exaggerated to emphasize clearer explanations.

[0046] The configuration of the invention to clarify the solution to the problem to be solved by the present invention is described in detail with reference to the attached drawings based on preferred embodiments of the present invention. In assigning reference numbers to the components of the drawings, the same reference number is assigned to identical components even if they are located in different drawings, and it is noted in advance that components of other drawings may be cited if necessary when describing the drawings.

[0047] FIG. 1 is a perspective view showing a multi-tube for an optical cable having flame retardancy according to one embodiment of the present invention, and FIG. 2 is a side cross-sectional view for explaining a multi-tube for an optical cable having flame retardancy according to one embodiment of the present invention.

[0048] First, referring to FIGS. 1 and 2, a multi-tube for a flame-retardant optical cable according to one embodiment of the present invention may include a plurality of inner tubes (100) into which an optical cable is inserted, an outer tube (200) that protects the inner tubes (100) from earth pressure or external force, and an outer tube flame-retardant layer (250) disposed on the outer surface of the outer tube (200).

[0049] The inner tube (100) is an important structural element that directly accommodates the optical cable and is designed to maximize protection of the optical cable and ease of installation. The inner tube (100) may be composed of multiple tubes, and each inner tube (100) provides an independent cable accommodation space to minimize interference between optical cables and to create a stable data transmission environment.

[0050] The inner tube (100) is formed from high-density polyethylene (HDPE), thereby ensuring excellent durability and flexibility. HDPE has excellent mechanical strength, which can effectively protect the optical cable from external impact or pressure, and the inner surface can be formed smoothly, which minimizes frictional resistance when inserting the optical cable. In addition, since HDPE is relatively lightweight and has excellent chemical resistance, it can be used for a long time in various environments and also prevents the penetration of moisture and external contaminants.

[0051] The structure of the inner tube (100) is designed to have a constant diameter and length, and maintains an appropriate inner diameter so that the optical cable can be easily inserted into the inner tube (100). In addition, the arrangement method of the inner tube (100) is considered so that the optical cable can be evenly distributed, and can be aligned while maintaining a constant spacing as needed. Although the inner tubes (100) have independent structures, they form a multi-tube system through combination with the outer tube, and the joint portion can be designed in a specific way to increase the bonding strength between the outer tube and the inner tube (100).

[0052] In addition, the inner tube (100) of the present invention may be provided in various sizes depending on the installation environment, and the diameter and wall thickness of the inner tube (100) may be adjusted according to the type and use of the optical cable. For example, when accommodating an optical cable for large-capacity data transmission, an inner tube (100) having a relatively wide inner diameter may be applied, and when accommodating multiple optical cables, an inner tube (100) having a denser arrangement may be configured.

[0053] In this embodiment, the inner tube (100) is designed to go beyond simply accommodating optical cables to maximize mechanical protection performance and to consider long-term durability and ease of installation. Through this, the multi-tube of the present invention can provide more stable performance than conventional COD tubes and can perform reliable optical cable protection functions in various environments.

[0054] In one embodiment of the present invention, the outer casing (200) serves as a key element that surrounds a plurality of inner tubes (100) and provides overall structural stability, and plays a role in protecting the optical cable from the external environment and supporting the inner tubes (100). The outer casing (200) is designed to protect the internal optical cable from various external shocks and environmental factors, while simultaneously enabling the formation of a multi-tube system through combination with the inner tubes (100).

[0055] The exterior (200) of the present invention can be formed into a corrugated shape, which contributes to increasing the mechanical strength of the exterior (200) and improving resilience against external impact. The corrugated structure is a structure in which curves are formed at regular intervals, which increases flexibility, making installation easy and allowing it to be applied without difficulty even in curved sections. In addition, this structure has resistance to external pressure, so it can provide high durability even in underground buried environments.

[0056] The outer casing (200) may be formed from high-density polyethylene (HDPE), thereby providing excellent mechanical strength and environmental resistance. HDPE has excellent impact resistance and chemical resistance, which can minimize the effects of moisture, acid rain, and contaminants. Additionally, the internal structure of the outer casing (200) may be optimized for bonding with the inner tube (100), and a design may be applied to increase the bonding strength between the outer casing (200) and the inner tube (100).

[0058] The outer casing (200) may be provided in various sizes depending on the installation environment, and the diameter, thickness, and cologage pattern of the outer casing (200) may be adjusted to suit specific optical cable system or infrastructure requirements. Additionally, the outer casing (200) of the present invention is designed to facilitate the placement of the optical cable and the inner tube (100) during construction, and the inner structure may be optimized to stably secure the inner tube (100).

[0059] In this embodiment, the outer casing (200) functions as a key element designed to simultaneously secure mechanical strength, flexibility, durability, and flame retardant performance, going beyond a protective structure that merely surrounds the inner tube (100), thereby providing optical cable protection performance that is significantly improved compared to conventional COD tubes.

[0060] The exterior flame-retardant layer (250) of the present invention is placed on the outer surface of the exterior to prevent the spread of combustion in the event of a fire and to minimize the generation of toxic gases and smoke.

[0061] The flame-retardant materials used in conventional optical cable tubes have the problem of emitting harmful gases when burned, and some flame retardants have limitations in that their performance deteriorates over time. In contrast, the outer flame-retardant layer (250) of the present invention uses FR-LSZH (Flame Retardancy-Low Smoke Zero Halogen) material to maximize fire safety.

[0062] The FR-LSZH flame retardant layer has a special structure containing magnesium hydroxide (Mg(OH)2), and in the event of a fire, magnesium hydroxide decomposes at high temperatures to cause an endothermic reaction that absorbs heat and simultaneously releases water vapor, thereby blocking the supply of oxygen necessary for combustion.

[0063] This significantly reduces the combustion speed and allows for the continuous suppression of flame spread while the flame-retardant layer is maintained. Furthermore, unlike conventional flame-retardant plastics, the flame-retardant layer of the present invention does not emit halogen compounds during combustion and produces extremely low smoke, thereby facilitating evacuation and rescue activities in the event of a fire. The outer flame-retardant layer (250) is formed with a uniform thickness, and in this embodiment, it is designed to be in the same ratio as the thickness of the outer surface to provide uniform flame-retardant performance while maintaining the durability of the outer surface. Through these structural characteristics, the outer flame-retardant layer (250) of the present invention possesses higher heat resistance and durability compared to conventional flame-retardant materials, and can exhibit stable performance over the long term in various environments. In particular, since it does not emit gases harmful to the human body even when used indoors or in enclosed spaces, it can be applied as an eco-friendly flame-retardant solution and can dramatically improve the fire safety of multi-tubes for protecting optical cables.

[0064] That is, one of the important features of the present invention is that an FR-LSZH (Flame Retardancy-Low Smoke Zero Halogen) exterior flame retardant layer (250) is disposed on the outer surface of the exterior (200). Even if the FR-LSZH flame retardant layer burns in a strong flame when a fire occurs, it minimizes smoke generation by utilizing the oxidation action of magnesium hydroxide and suppresses the release of toxic halogen gases. While general plastic-based materials can emit toxic gases when burned during a fire, the flame retardant layer of the exterior (200) of the present invention is designed to solve this problem. In addition, in this embodiment, the thickness of the exterior (200) and the thickness of the flame retardant layer of the exterior (200) can be formed to be the same, thereby ensuring uniform flame retardant performance while maximizing overall mechanical strength.

[0066] FIG. 3 is a side cross-sectional view illustrating a multi-tube for an optical cable having flame retardancy according to another embodiment of the present invention.

[0067] Referring to FIG. 3, a multi-tube for a flame-retardant optical cable according to another embodiment of the present invention may further include a silicon layer (150).

[0068] Below, only the silicon layer (150) is described in detail.

[0069] In another embodiment of the present invention, a silicone layer (150) is additionally formed on the inner surface of the inner tube (100) to minimize frictional resistance when inserting an optical cable and to simultaneously improve construction efficiency and cable protection performance.

[0070] The silicone layer (150) is formed in a uniform coating on the inner surface of the inner tube (100), and by lowering the friction coefficient between the optical cable and the inner tube (100), the optical cable can be inserted more smoothly and without damage. This enables stable installation by preventing the cable from bending or wearing out, especially in construction environments with long distances or many curved sections.

[0071] The silicone layer (150) applied in this embodiment may be formed using a special silicone-based thermosetting resin or liquid silicone rubber (LSR) having high heat resistance and wear resistance, and is selected considering the adhesion and durability with HDPE, which is the material of the inner tube (100). The silicone layer is generally applied with a thickness of approximately tens of micrometers (μm) and is precisely coated so as not to affect the strength or flexibility of the entire inner tube.

[0072] In addition, the silicon layer (150) can provide an anti-static function, thereby reducing cable damage or electromagnetic interference problems caused by the accumulation of static electricity that may occur during the insertion process of the optical cable. This allows for a more stable operating environment even when using a sensitive optical cable for data transmission.

[0073] The silicone layer (150) may be formed with a hardened or double structure to maintain adhesion with the inner tube (100) and ensure long-term durability, and is designed so that it does not easily peel off even with bending or compression deformation of the inner tube. In addition, since the inner wall of the inner tube is kept smooth, it acts favorably for the movement of the optical cable, contributing to improving overall constructability.

[0074] Accordingly, the silicon layer (150) of the present embodiment acts as a high-performance internal treatment layer capable of improving optical cable protection performance, ease of installation, durability, and electrostatic safety beyond simple coating functions, and is configured to provide reliable performance in various installation environments.

[0075] Thus, the multi-tube for optical cables of the present invention can be implemented as a premium protection system that simultaneously considers constructability and performance, and can provide enhanced user satisfaction compared to existing COD tubes.

[0076] FIG. 4 is a side cross-sectional view illustrating a multi-tube for an optical cable having flame retardancy according to another embodiment of the present invention.

[0077] Referring to FIG. 4, a multi-tube for a flame-retardant optical cable according to another embodiment of the present invention may further include a traction line (300).

[0078] Below, only the towing line (300) is described in detail.

[0079] In another embodiment of the present invention, a traction line (300) is additionally placed inside the inner tube (100) to maximize ease and efficiency of construction when installing an optical cable.

[0080] The traction line (300) is extended along the interior of the inner tube (100) and performs the function of assisting in the rapid and safe insertion of the optical cable into the interior of the inner tube (100). In particular, when an optical cable needs to be installed over a long distance or a complex path, a method of simply pushing the optical cable in may have limitations due to frictional resistance and the influence of gravity, and in such situations, the traction line (300) enables an efficient pulling method.

[0081] The traction line (300) of this embodiment is formed from a high-strength synthetic fiber material (e.g., polyester, nylon, polypropylene, etc.) and is configured to have excellent tensile strength while remaining flexible so that it can be stably positioned inside the inner tube without twisting. This minimizes the risk of the traction line breaking or being damaged by internal friction when the optical cable is inserted.

[0082] The traction line (300) can be installed in a state where it is exposed at both ends of the inner tube (100), and after connecting an optical cable to one end, the optical cable can be inserted into the inner tube by manually or mechanically pulling the traction line from the opposite end. This method is particularly useful in underground buried conduits, wiring inside indoor walls, and the construction of long-distance communication networks.

[0083] In addition, in this embodiment, the towing line (300) may be arranged at regular intervals along the center or wall surface to minimize structural interference with the inner tube (100), and if necessary, a fixing device or a guide part may be installed together on the inner circumference of the inner tube to prevent the towing line from twisting or being pulled out while moving.

[0084] The towing line (300) may be subjected to a surface treatment (e.g., Teflon coating, wax, etc.) to reduce friction in the section where it contacts the inner wall of the inner tube (100), thereby minimizing frictional resistance when inserting the optical cable, which can increase the speed and stability of construction. Additionally, the aforementioned flame-retardant layer (FR-LSZH) (not shown) may be applied to the surface of the towing line (300).

[0085] Additionally, the traction line (300) can be configured with various diameters and tensile strength specifications as needed, allowing for selection to provide appropriate traction force depending on the weight or length of the optical cable. This enables customized construction according to site conditions, and by independently applying the traction line to each of the multiple inner tubes in a multi-tube structure, the simultaneous or sequential installation of multiple lines can be performed more efficiently.

[0086] Accordingly, the traction line (300) of this embodiment provides substantial advantages that can compensate for the installation limitations of existing optical cable multi-tubes and significantly improve the convenience and efficiency of construction. In particular, rapid and stable optical cable placement is possible even in installation environments with many fault-prone conduits or curved sections, which can consequently contribute to improving the construction quality and maintenance efficiency of the entire optical communication system.

[0087] Through this, the multitube of the present invention is designed as a high-performance optical cable protection system that takes into account constructability during the installation phase, enabling it to provide high practicality and reliability in various environments and conditions.

[0088] FIG. 5 is a side cross-sectional view illustrating a multi-tube for an optical cable having flame retardancy according to another embodiment of the present invention.

[0089] Referring to FIG. 5, a multi-tube for a flame-retardant optical cable according to another embodiment of the present invention may have a single tube structure consisting only of an outer tube (200) and an outer flame-retardant layer (250) formed on the outer surface thereof, without an inner tube. Such a structure is suitable for environments requiring simple cable protection or sites where economic efficiency and ease of construction are important, and is designed to provide sufficient flame retardancy and mechanical protection functions while simplifying the structure.

[0090] Below, only the exterior (200) and the exterior flame-retardant layer (250) are described in detail.

[0091] The outer casing (200) of this embodiment is a structure that directly accommodates an optical cable, and the optical cable is placed directly inside without a separate inner tube. Accordingly, the outer casing (200) is designed to be a single tube while ensuring mechanical protection, moisture resistance, chemical resistance, and shock resistance of the optical cable. The outer casing (200) is typically formed of high-density polyethylene (HDPE) or a polymer material equivalent thereto, and has sufficient strength to protect the optical cable without deformation even under external load or impact.

[0092] In particular, in this embodiment, the exterior (200) can be formed into a corrugated structure, which improves resistance to external pressure and enables flexible construction even in curved sections or irregular terrain. The corrugated structure is a shape in which waves are formed at regular intervals, and because it has excellent mechanical restoring force and a superior effect in dispersing external loads, it can increase stability when buried underground or wiring within a structure.

[0093] The inner surface of the outer casing (200) is processed smoothly to reduce friction when inserting the cable, and the curvature or diameter of the inner wall can be adjusted to allow for smooth movement of the optical cable. The diameter, thickness, and spacing and depth of the waveform of the outer casing can be selected in various ways depending on the installation environment and cable specifications, and a high-capacity design capable of accommodating large or large quantities of cables is also possible.

[0094] Meanwhile, an exterior flame-retardant layer (250) is integrally formed on the outer surface of the exterior (200) to prevent the spread of combustion from the outside in the event of a fire and to minimize cable damage.

[0096] The outer flame retardant layer (250) is composed of FR-LSZH (Flame Retardancy-Low Smoke Zero Halogen) material, which is characteristically applied in the present invention. This material suppresses combustion conditions by utilizing the endothermic decomposition reaction of magnesium hydroxide (Mg(OH)2), which is the main component, to absorb heat and release water vapor even in high-temperature environments. As a result, flame spread is delayed, and the generation of smoke and toxic gases can be minimized.

[0097] In addition, since FR-LSZH does not emit halogen gases even during combustion, it can be safely used in indoor spaces, enclosed spaces, or densely populated areas, and is highly regarded as an eco-friendly flame-retardant material. The outer flame-retardant layer (250) is applied with a uniform thickness along the outer surface of the outer surface (200) and is designed to maintain a strong bonding strength with the outer surface. The ratio of the outer surface thickness to the flame-retardant layer thickness can be adjusted according to performance requirements and may be manufactured as an integrated structure.

[0098] In this way, the exterior (200) and the exterior flame-retardant layer (250) of the present embodiment simultaneously realize high-strength mechanical protection and excellent flame-retardant performance even within a simplified structure, thereby enabling stable use in various installation environments and, in particular, providing a solution suitable for building small and medium-sized optical cable infrastructure where economic efficiency and constructability are important.

[0099] The above detailed description is illustrative of the present invention. Furthermore, the foregoing describes preferred embodiments of the present invention, and the present invention may be used in various other combinations, modifications, and environments. That is, modifications or alterations are possible within the scope of the concept of the invention disclosed herein, the scope equivalent to the disclosed content, and / or the scope of the art or knowledge. The described embodiments describe the best state for implementing the technical concept of the present invention, and various modifications required for specific fields of application and uses of the present invention are possible. Accordingly, the above detailed description of the invention is not intended to limit the present invention to the disclosed embodiments. Additionally, the appended claims should be interpreted as including other embodiments. Explanation of the symbols

[0101] 100: Internal organ 150: Silicon layer 200: Appearance 250: Exterior flame-retardant layer 300: Towing line

Claims

Claim 1 An inner tube formed of High Density Polyethylene (HDPE), composed of multiple tubes to provide independent cable accommodation spaces; an outer tube formed of High Density Polyethylene (HDPE), formed to surround multiple inner tubes and molded into a corrugated shape; an outer flame-retardant layer formed of FR-LSZH (Flame Retardancy-Low Smoke Zero Halogen), disposed on the outer surface of the outer tube and formed with a thickness equal to that of the outer tube to maintain uniform flame-retardant performance while maximizing mechanical strength, and which minimizes smoke and the generation of halogen gases through the oxidation action of magnesium hydroxide even when burned in strong flames during a fire; and a silicone layer disposed on the inner surface of the inner tube, formed using a special silicone-based thermosetting resin or Liquid Silicone Rubber (LSR) having high heat resistance and wear resistance, and uniformly coated on the inner surface of the inner tube with a thickness of 10 to 100 μm. A flame-retardant multitube for optical cables, comprising: a traction line disposed inside the inner tube and installed in a pre-exposed state at both ends of the inner tube; wherein the silicone layer is formed with a curing treatment or a double structure to maintain adhesion with the inner tube and ensure long-term durability, the traction line is formed of a high-strength synthetic fiber material including polyester, nylon, polypropylene, or a combination thereof, and a surface treatment including Teflon coating, wax, or a combination thereof is applied to the section in contact with the inner wall of the inner tube to reduce friction. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 delete

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