Fire-resistant coaxial cable

Abstract

The present invention relates to a fire-resistant coaxial cable having an insulator capable of maintaining the shape of an inner conductor and an outer conductor at a high temperature of 750 ℃ or higher during a fire, thereby reliably maintaining a communication function for a predetermined period. To achieve the objective of the present invention, the present invention provides the fire-resistant coaxial cable comprising: the inner conductor disposed at the center; the insulator transversely wound on the outer side of the inner conductor and having fire-resistant properties; the outer conductor surrounding the outer side of the insulator and forming a coaxial structure with the inner conductor; and a cable jacket surrounding the outer side of the outer conductor, wherein the insulator has a dielectric constant of 2.7 to 9.0, an inclination angle of 20° to 60° during transverse winding, and an outer diameter of 75% to 98% of the outer diameter of the inner conductor.

Description

Fireproof coaxial cable

[0001] The present invention relates to a fire-resistant coaxial cable. More specifically, the present invention relates to a fire-resistant coaxial cable capable of stably maintaining communication functions for a certain period of time at high temperatures of 750°C or higher in the event of a fire, while also exhibiting superior characteristic impedance, flexibility, and structural stability.

[0002] Materials such as PE and PTFE, which are used as insulators in general coaxial cables, have a melting point of 100 to 325°C, which causes them to melt in a fire environment of at least 750°C or higher, and thus have the problem of not being able to sufficiently perform the insulating role between the inner and outer conductors.

[0003] Therefore, in a fire environment, a structure between the inner conductor and the outer conductor is maintained to secure insulation performance so that communication functions can be maintained for a certain period of time, and at the same time, a fire-resistant coaxial cable including an insulation structure that forms a concentric circle between the inner conductor and the outer conductor and has a dielectric constant equivalent to that of materials such as PE and PTFE so that the communication cable can faithfully perform its role as a transmission line even in an environment where there is no fire is required.

[0004] In particular, firefighting wireless communication auxiliary equipment is essential to be installed in high-rise and large buildings. In order to provide smooth wireless communication for firefighters at the scene of a fire in the event of a fire, it is desirable that the fire-resistant coaxial cable used in the firefighting wireless communication auxiliary equipment satisfies the fire resistance performance according to the standards IEC 60331-11 and IEC 60331-23. IEC 60331-11 and IEC 60331-23, which are fire resistance standards for fire-resistant coaxial cables, evaluate whether there is a short circuit between the inner conductor and the outer conductor for a certain period of time when a test voltage is applied at a flame temperature of at least 750℃.

[0005] Meanwhile, when applying a refractory material to an insulator to satisfy the standards IEC 60331-11 and IEC 60331-23, the curvature may be reduced or the characteristic impedance may be reduced due to an increase in permittivity, and when the structure of the insulator, etc. is modified to minimize the increase in permittivity, the structural stability of the cable may be reduced.

[0006] Therefore, there is an urgent need for a fire-resistant coaxial cable that can stably maintain communication functions for a certain period of time at high temperatures of 750℃ or higher when a fire occurs, while also having excellent characteristic impedance, flexibility, and structural stability.

[0007] The present invention aims to provide a fire-resistant coaxial cable capable of stably maintaining communication functions for a certain period of time at a high temperature of 750°C or higher when a fire occurs.

[0008] In addition, the present invention aims to provide a fire-resistant coaxial cable having excellent characteristic impedance, flexibility, structural stability, etc., despite the application of a fire-resistant material to the insulator.

[0009] In order to solve the above problem, the present invention,

[0010] A fire-resistant coaxial cable is provided, comprising: an inner conductor arranged in the center; an insulator having fire-resistant properties, which is wound transversely around the outer side of the inner conductor; an outer conductor that wraps around the outer side of the insulator and forms a coaxial structure with the inner conductor; and a cable jacket that wraps around the outer side of the outer conductor; wherein the insulator has a dielectric constant of 2.7 to 9.0, an inclination angle of 20 to 60° during transverse winding, and an outer diameter of 75 to 98% of the outer diameter of the inner conductor.

[0011] Here, a fire-resistant coaxial cable is provided, characterized in that the outer diameter of the inner conductor of the insulator is 75 to 95%.

[0012] Furthermore, a fire-resistant coaxial cable is provided, characterized in that the insulator comprises a refractory elastomer material.

[0013] In addition, the present invention provides a fire-resistant coaxial cable, characterized in that the insulator comprises an insulating core and a refractory layer surrounding the insulating core, the insulating core includes a tensile member, and the refractory layer includes a refractory elastomer material.

[0014] And, a fire-resistant coaxial cable is provided, characterized in that the fire-resistant elastomer material is silicone rubber.

[0015] Furthermore, a fire-resistant coaxial cable is provided, characterized in that the tensile strength of the insulating core including the tensile member is 5 g / TEX or more.

[0016] Meanwhile, a fire-resistant coaxial cable is provided, characterized in that the tensile member includes at least one of basalt fiber, glass fiber, silica fiber, ceramic fiber, or aramid fiber materials.

[0017] Here, a fire-resistant coaxial cable is provided, characterized in that the tensile member includes glass yarn.

[0018] In addition, the above-mentioned insulating core provides a fire-resistant coaxial cable characterized in that the temperature at which shape deformation occurs is higher than that of the above-mentioned fire-resistant layer.

[0019] Meanwhile, a fire-resistant coaxial cable is provided, characterized in that it includes a low-dielectric layer surrounding the insulator, and the dielectric constant of the low-dielectric layer is 2.5 or less.

[0020] Here, a fire-resistant coaxial cable is provided, characterized in that the low-pass filter layer includes at least one of PE (Polyethylene), HDPE (High-Density Polyethylene), PTFE (Polytetrafluoroethylene), and FEP (Fluorinated ethylene propylene).

[0021] In addition, a fire-resistant coaxial cable is provided, characterized in that it includes an insulating fire-resistant reinforcing layer that surrounds the insulator and reinforces the fire-resistant performance of the fire-resistant coaxial cable.

[0022] Here, a fire-resistant coaxial cable is provided, characterized in that the insulating refractory reinforcing layer includes at least one of basalt fiber, silica fiber, ceramic fiber, glass fiber, and mica tape.

[0023] Meanwhile, a fire-resistant coaxial cable is provided, characterized in that it further includes one or more fire-resistant tape layers wrapping the outer side of the outer conductor to enhance the fire-resistant performance of the fire-resistant coaxial cable.

[0024] And, a fire-resistant coaxial cable is provided, characterized in that the fire-resistant tape layer includes at least one of a mica tape, a glass tape, and a metal tape.

[0025] In addition, a fire-resistant coaxial cable is provided, characterized in that it further includes a conductor fire-resistant reinforcing layer that wraps around the outer side of the inner conductor to enhance the fire-resistant performance of the fire-resistant coaxial cable.

[0026] Here, a fire-resistant coaxial cable is provided, characterized in that the conductor refractory reinforcing layer includes at least one of basalt fiber, silica fiber, ceramic fiber, glass fiber, and mica tape.

[0027] Meanwhile, a fire-resistant coaxial cable is provided, characterized in that the insulator includes an insulating core and a refractory layer surrounding the insulating core, the insulating core of the insulator includes polyethylene, and the refractory layer of the insulator includes at least one of basalt fiber, silica fiber, ceramic fiber, glass fiber, and mica tape.

[0028] In addition, a fire-resistant coaxial cable is provided, characterized in that the inner conductor and the outer conductor are made of copper or a copper alloy material.

[0029] And, the outer conductor provides a fire-resistant coaxial cable characterized by having a corrugated pipe structure in which corrugated mountains and corrugated valleys are repeatedly formed.

[0030] According to the fire-resistant coaxial cable according to the present invention, the insulator arranged between the inner conductor and the outer conductor is composed of a fire-resistant material, and can maintain insulation between the inner conductor and the outer conductor at a high temperature of 750°C or higher when a fire occurs, thereby realizing excellent fire-resistant performance.

[0031] In addition, according to the fire-resistant coaxial cable according to the present invention, the insulator is arranged to be wound transversely on the outside of the inner conductor, and by precisely designing the inclination of the transverse winding of the insulator and the outer diameter of the insulator, the characteristic impedance, flexibility, structural stability, etc. can be maximized.

[0032] In addition, according to the fire-resistant coaxial cable of the present invention, communication performance can be further improved by adding a low-dielectric layer to the outside of the insulator.

[0033] In addition, according to the fire-resistant coaxial cable of the present invention, the fire-resistant characteristics can be further improved by adding an insulating fire-resistant reinforcing layer to the outside of the insulator.

[0034] Figure 1 illustrates a configuration diagram of a firefighting wireless communication auxiliary equipment including a fire-resistant coaxial cable according to the present invention.

[0035] Figure 2 illustrates a multi-stage stripped perspective view of one embodiment of a fire-resistant coaxial cable according to the present invention.

[0036] Figure 3 shows a partially enlarged perspective view of the refractory coaxial cable illustrated in Figure 2.

[0037] FIG. 4 illustrates a cross-sectional view of one embodiment of the refractory coaxial cable illustrated in FIG. 2.

[0038] Figure 5 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0039] Figure 6 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0040] Figure 7 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0041] Figure 8 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0042] Figure 9 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosure is thorough and complete, and to sufficiently convey the spirit of the invention to those skilled in the art. Like reference numbers designate like elements throughout the specification.

[0044] Figure 1 illustrates a configuration diagram of a firefighting wireless communication auxiliary equipment including a fire-resistant coaxial cable according to the present invention.

[0045] As illustrated in FIG. 1, the auxiliary equipment for firefighting wireless communication may include a fire-resistant coaxial cable (100) constituting a wired communication network, a fire-resistant leaky coaxial cable (100L) constituting a wireless communication network, an indoor antenna (200) for transmitting and receiving wireless signals to and from a wireless terminal (t) carried by a firefighter, a central amplifier (300) installed in a disaster prevention room (d) or the like for amplifying and relaying wireless signals transmitted and received, a line amplifier (400) for amplifying signals on a transmission and reception line, a distributor (500) for distributing signals, an outdoor antenna (600) for transmitting and receiving wireless signals to and from a wireless terminal (t) outside a building, a power supply device (700) for supplying power to the line amplifier (400), etc.

[0046] As illustrated in FIG. 1, the auxiliary fire-fighting wireless communication equipment may be equipped with a fire-resistant coaxial cable (100) for constructing a wired communication network composed of various equipment used for fire prevention and disaster prevention, such as an indoor antenna (200), a central amplifier (300), a line amplifier (400), a distributor (500), an outdoor antenna (600), a power supply device (700), and lines connecting them. In addition, a fire-resistant leakage coaxial cable (100L) may be laid in an underground space, such as an underground parking lot, where the area inside a building is wide and the space is not partitioned, to construct a wireless communication network. Of course, if necessary, not only the fire-resistant leakage coaxial cable but also the indoor antenna (200) may be installed in the underground space of a building.

[0047] For reference, according to the fire safety standards for wireless communication auxiliary equipment (NFSC 505), the leaky coaxial cable and indoor antenna (200) can transmit and receive electromagnetic waves in the range of 440 MHz to 450 MHz, which is a fire communication frequency.

[0048] This type of wireless communication network can enable communication between firefighters and the fire command center or control room.

[0049] The above fire-fighting wireless communication auxiliary equipment is installed above and below ground of the building (b) and may be equipped with multiple indoor antennas (200) capable of wireless communication with each wireless terminal (t) carried by firefighters.

[0050] The above indoor antenna (200) can be installed in the indoor space of each floor of the building (b), and enables mutual communication between firefighters carrying wireless terminals (t) or between firefighters carrying wireless terminals (t) and personnel within the fire prevention room (d).

[0051] Here, the indoor antenna (200) can be connected to the central amplifier (300) of the fire prevention room (d) located within the building (b) via a fire-resistant coaxial cable (100).

[0052] In addition, the above fire-fighting wireless communication auxiliary equipment may be configured to include a plurality of line amplifiers (400) that are connected to the indoor antenna (200) via a fire-resistant coaxial cable (100) and amplify signals transmitted and received from the indoor antenna (200).

[0053] In addition, the firefighting wireless communication auxiliary equipment illustrated in FIG. 1 may be configured to include a plurality of distributors (500) for branching signals transmitted and received from a plurality of indoor antennas (200).

[0054] The above-mentioned distributor (500) may be provided in each area where a signal is branched into multiple coaxial cables, and the distributor (500) may synthesize a signal received from the indoor antenna (200) or branch a signal provided from a central amplifier and transmit each branched signal to the indoor antenna (200).

[0055] In addition, the above fire-fighting wireless communication auxiliary equipment may be configured to include an outdoor antenna (600) installed outdoors. The outdoor antenna (600) enables voice communication between a wireless terminal (t) carried by a firefighter or fire commander outside a building and a firefighter inside a building or communication with a central amplifier (300) in a fire prevention room (d).

[0056] Here, even if the outdoor antenna (600) is not installed, the firefighting wireless communication auxiliary equipment can be connected by wire to a wireless terminal (t) carried by a firefighter or fire commander outside the building to enable voice communication with firefighters inside the building or communication with the central amplifier (300) of the fire prevention room (d).

[0057] In addition, the above fire-fighting wireless communication auxiliary equipment may be configured to include a power supply device (700) for supplying commercial power or emergency power. The power supply device (700) may provide power to a line amplifier (400) or the like through a fire-resistant coaxial cable (100) or a separate power cable.

[0058] Meanwhile, the overall configuration of the fire-fighting wireless communication auxiliary equipment to which the fire-resistant coaxial cable (100) according to the present invention is applied is not limited to the configuration shown in FIG. 1, and may be configured by selectively combining at least some of the indoor antenna (200), central amplifier (300), line amplifier (400), distributor (500), outdoor antenna (600), and power supply device (700), or may be configured by additionally including various equipment constituting a typical fire-fighting wireless communication auxiliary equipment in addition to the configuration described above.

[0059] Meanwhile, although an example in which a fire-resistant coaxial cable (100) according to the present invention is applied to a firefighting wireless communication auxiliary device is presented through FIG. 1, the fire-resistant coaxial cable according to the present invention can be applied to various environments in which it is necessary to maintain a communication function when a high temperature occurs.

[0060] Hereinafter, the structure of the fire-resistant coaxial cable (100) according to the present invention will be examined in detail with reference to FIG. 2 and below.

[0061] FIG. 2 illustrates a multi-stage stripped perspective view of one embodiment of a fire-resistant coaxial cable according to the present invention, FIG. 3 illustrates a partial enlarged perspective view of the fire-resistant coaxial cable illustrated in FIG. 2, and FIG. 4 illustrates a cross-sectional view of the fire-resistant coaxial cable illustrated in FIG. 2.

[0062] As illustrated in FIGS. 2 to 4, a fire-resistant coaxial cable (100) according to the present invention may be configured to include an inner conductor (10) disposed at a central portion; an insulator (20) wound transversely around the outer side of the inner conductor (10) and including a fire-resistant composition; an outer conductor (30) wrapping around the outer side of the insulator (20) and forming a coaxial structure with the inner conductor (10); and a cable jacket (40) wrapping around the outer side of the outer conductor (30).

[0063] The inner conductor (10) is provided at the center and serves to transmit communication signals. Typically, copper or aluminum is used as the material for the inner conductor (10) of a coaxial cable. However, since the melting point of copper is 1,084°C, while the melting point of aluminum is 660°C, the inner conductor (10) is preferably made of copper or a copper alloy material. The cross-section of the inner conductor (10) is circular and the diameter can be configured to be 5.0 millimeters (mm) or less.

[0064] The above outer conductor (30), like the above inner conductor (10), may be composed of copper or a copper alloy material, and may have a corrugated pipe structure for ease of bending. The corrugations of the corrugated pipe may be spiral or circular. The spiral corrugated structure increases flexibility, allowing the cable to be easily bent, facilitating installation and increasing durability by increasing resistance to external pressure. On the other hand, the circular corrugated structure may be less expensive due to a relatively simple manufacturing process and may be lighter due to its simple structure. Therefore, the spiral corrugated structure is advantageously applied in installation environments that require movement or bending, while the circular corrugated structure is advantageously applied in fixed installation environments where cost reduction is important.

[0065] The above outer conductor (30) forms a coaxial structure with the inner conductor (10) and is provided so as to be spaced apart from the inner conductor (10). The above outer conductor (30) is provided so as to circularly wrap the radially outer side of the insulator (20) provided between the inner conductor (10) and the outer conductor (30).

[0066] In this way, the fire-resistant coaxial cable (100) according to the present invention is formed in a coaxial structure in which the inner conductor (10) and the outer conductor (30) have the same central axis.

[0067] Typically, coaxial cables generally use a flexible and thin metal material as the outer conductor (30), but the outer conductor (30) constituting the fire-resistant coaxial cable (100) according to the present invention may be composed of a metal material having excellent rigidity in order to maintain a gap with the inner conductor (10) to secure electrical characteristics, and preferably, the outer conductor (30) may be composed of copper or a copper alloy material, like the inner conductor (10).

[0068] In addition, the external conductor (30) is formed as a corrugation structure in which wrinkles and wrinkle valleys are repeatedly formed, and the flexibility and rigidity of the external conductor (30) can be reinforced by the corrugation structure.

[0069] In addition, the thickness of the outer conductor (30) may be configured in the range of 0.14 millimeters (mm) to 0.45 millimeters (mm). If the thickness of the outer conductor (30) is less than 0.14 millimeters (mm), the rigidity is insufficient, so that the gap between the inner conductor (10) and the outer conductor (30) cannot be maintained well, whereas if the thickness is greater than 0.45 millimeters (mm), the bending characteristics are deteriorated, so that the outer conductor (30) may be easily damaged due to cable bending or bending.

[0070] The outer side of the above outer conductor (30) may be covered with a cable jacket (40). The cable jacket (40) may be made of polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polyethylene (PE), etc. as a base resin, and may be composed of an insulating composition in which a refractory filler is added to the base resin, if necessary.

[0071] An insulator (20) is provided on the outside of the inner conductor (10). The insulator (20) is configured in the form of a rope or wire and may be provided in a transverse manner with a preset pitch (P) range on the outside of the inner conductor (10). The insulator (20) maintains a constant gap between the inner conductor (10) and the outer conductor (30) and serves to insulate the inner conductor (10).

[0072] The fire-resistant coaxial cable (100) according to the present invention is not formed in a form in which the insulator (20) is entirely filled around the outer circumference of the inner conductor (10) as in the past, but is formed in the form of a rope or wire and spirally wound around the outer side of the inner conductor (10), thereby reducing the cross-sectional area of ​​the insulator (20), thereby reducing the absolute amount of the insulator (20), which is relatively weak in fire resistance compared to the inner conductor (10) and the outer conductor (30), thereby improving the flame retardancy, while improving the flexibility of the cable and minimizing the cable manufacturing cost, and stably maintaining the coaxial structure between the inner conductor (10) and the outer conductor (30) through the insulator (20).

[0073] In addition, the insulator (20) may be provided with a material described below to satisfy the fire resistance characteristics and may have a dielectric constant of 2.7 to 9.0. However, if such an insulator (20) fills the space between the inner conductor (10) and the outer conductor (30), the dielectric constant may be excessively high, which may deteriorate the communication performance of the coaxial cable. Therefore, as described above, the insulator (20) is wound horizontally on the outside of the inner conductor (10) so that an air layer is formed around the insulator (20), thereby reducing the dielectric constant between the inner conductor (10) and the outer conductor (30), thereby improving the transmission characteristics of electromagnetic wave signals transmitted and received through the fire resistance coaxial cable (100).

[0074] Specifically, the inclination angle (θ) at which the insulator (20) is wound transversely around the outer side of the inner conductor (10) may be 20 to 60°. The inclination angle (θ) may be defined as the angle between the base and the hypotenuse of a right triangle having a base equal to half the pitch (P) of the insulator (20) when wound transversely as illustrated in FIG. 3 and a height equal to the inner diameter (D) of the outer conductor (30). The inner diameter (D) of the outer conductor (30) may be the inner diameter between the valleys of the wrinkles in the outer conductor (30) in which wrinkles are formed.

[0075] Here, if the above-mentioned inclination angle (θ) exceeds 60°, the structure of the cable is stable, but the dielectric constant between the inner conductor (10) and the outer conductor (30) increases due to the insulator (20), so that the communication characteristics of the cable deteriorate, the cable becomes excessively stiff, so that the flexibility deteriorates, and the manufacturing cost may increase due to an unnecessary increase in material costs.

[0076] On the other hand, if the above-mentioned inclination angle (θ) is less than 20°, the manufacturing cost is reduced due to the reduction in material cost, and the dielectric constant is lowered, so the attenuation rate during communication is small, but the cable is structurally unstable, such as the outer conductor being easily crushed when bent, and a short circuit may occur due to the inner conductor and outer conductor coming into contact.

[0077] Meanwhile, the outer diameter of the insulator (20) may be 75 to 98%, more preferably 75 to 95%, of the diameter of the inner conductor (10). Here, if the outer diameter of the insulator (20) is less than 75% of the diameter of the inner conductor (10), it is difficult to secure a gap between the inner conductor (10) and the outer conductor (30) to satisfy the characteristic impedance of 50±5 Ω, and if it is more than 98%, when the insulator (20) is horizontally wound on the outside of the inner conductor (10), excessive tension may be applied to the inner conductor (10), making it difficult for the inner conductor (10) to maintain a straight line in the longitudinal direction, which may deteriorate structural stability.

[0078] Meanwhile, fire-resistant coaxial cables for signal transmission within firefighting radio communication auxiliary equipment should preferably satisfy the fire resistance performance specified in international standards IEC 60331-11 and IEC 60331-23. As mentioned above, standards IEC 60331-11 and IEC 60331-23 assess whether there is a short circuit between the inner and outer conductors when a test voltage is applied at a flame temperature of at least 750°C.

[0079] Accordingly, in order to satisfy the fire resistance performance according to the standards IEC 60331-11 and IEC 60331-23, the fire-resistant coaxial cable (100) according to the present invention can be designed so that the insulator (20) constituting the fire-resistant coaxial cable (100) can secure excellent fire resistance performance at a high temperature of 750°C or higher when a fire occurs, while at the same time being able to maintain the internal structure of the insulator at a high temperature.

[0080] In addition, the fire-resistant coaxial cable (100) including the insulator (20) includes a high-conductivity center conductor (10), a low-permittivity insulator (20), and a high-conductivity outer conductor (30) so that the inherent function of the communication cable can be properly performed even in an environment where no fire occurs, and can be designed and manufactured to maintain a constant structure between the center conductor (10) and the outer conductor (30).

[0081] The insulator (20) constituting the fire-resistant coaxial cable (100) according to the present invention may include a fire-resistant insulating material. The fire-resistant insulating material may be an insulating material having fire-resistant properties, such as a fire-resistant elastomer material, basalt, silica, glass fiber, ceramic, mica, etc., and among these, the fire-resistant elastomer material may be silicone rubber, fluororubber, fluorosilicone, ethylene acrylate rubber, acrylic rubber, etc. In particular, in order to form the insulator (20) into a wire or rope shape with a certain diameter and to be wound transversely around the inner conductor (10), it is preferable that it is a refractory elastomer material that is easy to implement in thickness and is flexible. Hard fire-resistant materials such as basalt or silica may be difficult to be wound transversely around the outer side of the inner conductor, and although they may be formed into a fiber shape to implement the insulator, it may be difficult to form them to have a certain diameter.

[0082] The above insulator (20) may preferably include refractory silicone rubber, in particular, among the refractory elastomer materials, in order to implement high refractory performance and low dielectric constant between the inner conductor (10) and the outer conductor (30).

[0083] Figure 5 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0084] As illustrated in FIG. 5, another embodiment of a fire-resistant coaxial cable (100) according to the present invention is configured to include an inner conductor (10), an insulator (20), an outer conductor (30), and a cable jacket (40) similar to the embodiment illustrated in FIG. 4, but the insulator (20) of the fire-resistant coaxial cable (100) may be configured to include an insulating core (21) formed by being embedded along the longitudinal direction, and a fire-resistant layer (23) formed of a refractory composition and surrounding the insulating core (21).

[0085] In the embodiment illustrated in FIG. 5, a detailed description of the dielectric constant, transverse winding inclination angle, and outer diameter of the inner conductor (10), outer conductor (30), cable jacket (40), and insulator (20) constituting the fire-resistant coaxial cable (100) of the present invention is omitted as it overlaps with the description referring to FIG. 4.

[0086] The above-mentioned refractory layer (23) may be configured to include the refractory insulating material presented in the above-mentioned Figure 4, and in particular, may include a refractory elastomer material. For example, the above-mentioned refractory layer (23) may include at least one of silicone rubber, fluororubber, fluorosilicone, ethylene acrylate rubber, acrylic rubber, etc. When the above-mentioned refractory layer (23) includes an elastomeric material, the above-mentioned insulator (20) can be easily rolled in close contact with the outside of the inner conductor (10), thereby improving structural stability.

[0087] In particular, the refractory layer (23) may include silicone rubber. When an insulator made of silicone rubber as a main material is wound horizontally, the insulator can be sufficiently closely adhered to the outer surface of the inner conductor (10) and the inner surface of the outer conductor (30), respectively. Silicone rubber has a refractory performance that is far superior to that of general elastic polymer materials, a low dielectric constant, and is a thermosetting material, so that it can be cured at high temperatures to maintain the separation structure between the inner conductor (10) and the outer conductor (30) even in a high-temperature environment, thereby allowing the refractory coaxial cable to maintain its function.

[0088] The above-mentioned refractory layer (23) can be formed to have a circular cross-section on the outside of the insulating core (21) by extruding a refractory elastomer material, etc. As an example of the refractory elastomer material constituting the above-mentioned refractory layer (23), it can be formed by adding various refractory fillers, such as magnesium hydroxide (MDH), aluminum hydroxide (ATH), mineral powders such as quartz or wollastonite, mineral fibers, and glass fibers, to silicone rubber as a base resin.

[0089] Silicone rubber, as the above-mentioned refractory elastomer material, may be a polymer in which silicon (Si) and oxygen containing organic groups are chemically bonded to each other through siloxane bonds. This siloxane bond exhibits excellent bonding stability at high temperatures, making it suitable as a refractory material. In addition, silicone rubber has a relatively low heat release rate and does not emit toxic gases when burned, making it an advantageous environmentally friendly refractory material.

[0090] The refractory silicone rubber as the refractory elastomer material constituting the refractory layer (23) may include a silicone rubber as a base resin and a refractory filler, thereby realizing sufficient refractory performance that can maintain the separation structure between the inner conductor (10) and the outer conductor (30) of the refractory coaxial cable (100) even when the refractory coaxial cable (100) is placed in a high-temperature environment and the silicone rubber is partially thermally decomposed, oxidized, or burned.

[0091] The above insulating core (21) can be formed by being embedded within the fire-resistant layer (23) in the shape of a long wire, rope, or thread. By further including the insulating core (21), the tensile strength of the insulator (23) can be reinforced and the fire-resistant performance can be further improved.

[0092] To impart the above-described tension, the insulating core (21) may be configured to include a tensile member. The tensile member may include a fiber yarn such as a reinforcing fiber, for example, basalt fiber, glass fiber, silica fiber, ceramic fiber, or aramid fiber material, and preferably, may include glass yarn in consideration of fire resistance and processability.

[0093] The glass yarn constituting the above insulating core (21) can be formed by twisting fine inorganic glass fibers of 5 μm to 13 μm obtained by melt spinning refined raw materials at a high temperature of 1,200 to 1,500°C into a yarn shape by focusing hundreds of them.

[0094] The above insulating core (21) has a long fiber, wire or rope shape to maintain the shape of the insulator (20) and reinforce the tensile strength, and may have a tensile strength higher than that of the fire-resistant layer (23) including the tensile member, and preferably, the tensile strength may be 5 g / TEX or more. If the tensile strength of the insulating core (21) including the tensile member is less than 5 g / TEX, the functions of maintaining the shape of the insulator (20) and reinforcing the tensile strength may not be sufficiently performed. The tensile strength of the insulating core (21) may be a value measured by the ASTM D885 standard test method.

[0095] The outer diameter of the insulating core (21) may be 30% or less of the outer diameter of the refractory layer (23). If the outer diameter of the insulating core (21) is 30% or more of the outer diameter of the refractory layer (23), the flexibility of the insulator (20) decreases, the adhesion between the insulator (20) and the inner conductor (10) deteriorates, and workability may deteriorate or cracks may occur during transverse winding.

[0096] That is, if the outer diameter of the inflexible material insulating core (21) embedded inside the flexible material refractory layer (23) constituting the insulator (20) is too large, the structural stability of the coaxial structure in which the insulator (20) is interposed is reduced, a large force is required during the transverse winding operation, and there is a problem that the insulator (20) may be damaged during the transverse winding process.

[0097] In addition, the insulating core (21) may include an insulating material having higher refractory performance than the refractory layer (23), so that the temperature at which shape deformation occurs in a high-temperature environment may be higher. For example, even when the refractory layer (23) is deformed in an extreme situation of 1000°C or higher, the insulating core (21) may be configured to space the inner conductor (10) and the outer conductor (30) so that the refractory coaxial cable maintains its function as a cable.

[0098] In this way, the insulator (20) constituting the fire-resistant coaxial cable (100) according to the present invention is configured to include an insulating core (21) and a fire-resistant layer (23) made of a fire-resistant composition that surrounds the insulating core (21), thereby ensuring excellent fire-resistant performance at high temperatures of 750°C or higher, which is the test temperature of standards IEC 60331-11 and IEC 60331-23, while maintaining the internal structure between the inner and outer conductors by the insulator (20).

[0099] The dielectric constant of the insulator (20) including the insulating core (21) and the refractory layer (23) may be 2.7 to 9.0 as described in the above-described Fig. 4, which may be calculated as ((dielectric constant of the insulating core * cross-sectional area of ​​the insulating core) + (dielectric constant of the refractory layer * cross-sectional area of ​​the refractory layer)) / (cross-sectional area of ​​the insulating core + cross-sectional area of ​​the refractory layer).

[0100] Figure 6 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0101] As illustrated in FIG. 6, another embodiment of a fire-resistant coaxial cable (100) according to the present invention is configured to include an inner conductor (10), an insulator (20), an outer conductor (30), and a cable jacket (40) similar to the embodiment illustrated in FIG. 5, but the fire-resistant coaxial cable (100) may further include a low-dielectric constant layer (50) wrapping around the outer circumference of the insulator (20). A detailed description of the inner conductor (10), the insulator (20), the outer conductor (30), and the cable jacket (40) constituting the fire-resistant coaxial cable (100) of the present invention in the embodiment illustrated in FIG. 6 overlaps with the description with reference to FIGS. 4 and 5, and thus will be omitted. In particular, the insulator (20) may be applied to one of the embodiments illustrated in FIG. 4 and FIG. 5.

[0102] The fire-resistant coaxial cable (100) according to the present invention may additionally include a low-dielectric constant layer (50) that wraps the outer side of the insulator (20) in the longitudinal direction.

[0103] The low-dielectric layer (50) above is composed of a layer having a dielectric constant of 2.5 or less, and can reinforce the dielectric properties of the cable. The low-dielectric layer can be composed of one or at least two or more low-dielectric materials selected from the group consisting of polyethylene (PE), high-density polyethylene (HDPE), polytetrafluoroethylene (PTFE), and fluorinated ethylene propylene (FEP). The low-dielectric material can be coated or extruded on the outside of the insulator (20).

[0104] In this way, by coating a low-dielectric constant material on the outside of the insulator (20) to add a low-dielectric constant layer (50) and winding the insulator (20) transversely on the outside of the inner conductor (10) in a preset pitch range to form an insulating structure between the inner conductor (10) and the outer conductor (30), the fire resistance performance can be maintained while reducing the dielectric constant, and the original communication performance of the coaxial cable can be improved through this reduction in the dielectric constant.

[0105] As another example, an insulating refractory reinforcing layer (not shown) having high refractory properties may be further included, which wraps around the outer side of the low-k layer (50) or the outer circumferential surface of the insulator (20) in the longitudinal direction. Since the insulating refractory reinforcing layer wraps around the outer side of the insulator (20), it can block mutual contact between the inner conductor (10) and the outer conductor (30), thereby enhancing the insulating function of the insulator (20).

[0106] The above-mentioned insulating refractory reinforcement layer may be composed of one or at least two or more highly refractory insulating materials selected from the group consisting of basalt fiber, mica tape, silica fiber, ceramic fiber, and glass fiber.

[0107] The basalt fiber constituting the above-mentioned insulating refractory reinforcing layer can be manufactured by melting basalt powder made of basalt at 1,500°C and spinning it into filaments of 9 μm to 20 μm in size using centrifugal force.

[0108] The chemical composition of basalt is high in Cao, MgO, and FeO+Fe2O3, and the SiO2 content is less than 52%. Due to this chemical composition, basalt has excellent chemical stability and has excellent heat resistance at high temperatures.

[0109] The basalt fibers constituting the above-mentioned insulating refractory reinforcing layer may be configured in the form of braided basalt fibers or may be configured in the form of coating the basalt fibers by applying a coating material such as carbon-based, silicone-based or urethane-based.

[0110] The mica tape constituting the above-mentioned insulating refractory reinforcing layer can be manufactured in the form of a tape by bonding white mica (soft mica, hard mica) powder obtained from the natural mineral muscovite onto a PE film or glass fiber fabric. The number of turns of the mica tape can be varied depending on the required refractory performance, cable structure, and intended use.

[0111] The glass fibers constituting the above insulating refractory reinforcing layer can be either long fibers wound by high-speed drawing out molten glass or short fibers manufactured into a plane by blowing molten glass using a centrifugal force method or a flame method.

[0112] Here, the glass fibers constituting the insulating refractory reinforcement layer may be provided in the form of a glass tape by bonding glass fibers coated with silicone adhesive or acrylic adhesive, etc., to a polymer substrate. In addition, the glass fibers constituting the insulating refractory reinforcement layer may be provided in the form of horizontally winding glass fibers on the outer surface of the insulator (20) and coating the glass yarns using a non-metallic or metallic coating material.

[0113] The fire-resistant coaxial cable (100) according to the present invention further includes an insulating fire-resistant reinforcing layer on the outside of the insulator (20), thereby further reinforcing the fire-resistant and insulating functions through the insulator, thereby allowing the cable to maintain its function for a certain period of time even at high temperatures of 1000°C or higher.

[0114] In addition, the insulating refractory reinforcement layer that wraps around the outside of the insulator (20) may include an insulating material with higher refractory performance than the refractory layer (23), so that the temperature at which shape deformation occurs in a high-temperature environment may be higher. For example, even when the insulator (20) is deformed in an extreme situation of 1000°C or higher, the insulating refractory reinforcement layer may be configured to separate the inner conductor (10) and the outer conductor (30) so that the cable can maintain its communication function.

[0115] Figure 7 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0116] As illustrated in FIG. 7, another embodiment of a fire-resistant coaxial cable (100) according to the present invention is configured to include an inner conductor (10), an insulator (20), an outer conductor (30), a cable jacket (40), a low-dielectric constant layer (50), and an insulating fire-resistant reinforcement layer, similar to the embodiment illustrated in FIG. 6, but may further include a fire-resistant tape layer (60) that wraps around the outer circumference of the outer conductor (30) to reinforce the fire-resistant performance of the fire-resistant coaxial cable (100).

[0117] In the embodiment illustrated in Fig. 7, any duplicate content with reference to Figs. 4 to 6 will be omitted.

[0118] The fire-resistant coaxial cable (100) according to the present invention may be provided with a fire-resistant tape layer (60) having high fire-resistant properties that wraps the outer side of the outer conductor (30) in the longitudinal direction.

[0119] The above-mentioned refractory tape layer (60) may be composed of one or more highly refractory materials, such as a mica tape, a glass tape, and a metal tape. In this way, the refractory tape layer (60) may be composed of a tape member to secure flexibility and bending characteristics of the refractory coaxial cable (100).

[0120] The description of the mica tape or glass tape constituting the above refractory tape layer (60) is the same as that described in the above insulating refractory reinforcement layer.

[0121] The metal tape constituting the above refractory tape layer (60) may be made of a refractory metal material such as copper, aluminum, iron, copper alloy, or aluminum alloy.

[0122] As shown in FIG. 7, when the fire-resistant coaxial cable (100) according to the present invention has the fire-resistant tape layer (60), not only the insulator (20) and the insulating fire-resistant reinforcement layer, but also the fire-resistant tape layer (60) additionally performs a fire-resistant function, so that the fire-resistant coaxial cable (100) according to the present invention has excellent fire resistance even at high temperatures of 1000°C or higher, and can maintain the cable function for a certain period of time.

[0123] Figure 8 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0124] As illustrated in FIG. 8, another embodiment of a fire-resistant coaxial cable (100) according to the present invention is configured to include an inner conductor (10), an insulator (20), an outer conductor (30), a cable jacket (40), a low-dielectric layer (50), an insulating fire-resistant reinforcement layer, and a fire-resistant tape layer (60), similar to the embodiment illustrated in FIG. 7, but the fire-resistant coaxial cable (100) may further include a conductor fire-resistant reinforcement layer (70) that wraps around the outer circumference of the inner conductor (10) to further improve fire-resistant performance.

[0125] In the embodiment illustrated in Fig. 8, any duplicate content with reference to Figs. 4 to 7 will be omitted.

[0126] A fire-resistant coaxial cable (100) according to the present invention may be provided with a conductor fire-resistant reinforcing layer (70) having high fire-resistant insulation properties, which wraps around the outer surface of an inner conductor (10) disposed in the center in the longitudinal direction.

[0127] The conductor refractory reinforcement layer (70) may be composed of one or at least two or more highly refractory insulating materials selected from among basalt fibers, mica tapes, silica fibers, ceramic fibers, and glass fibers, similar to the insulation refractory reinforcement layer. Each refractory material of the conductor refractory reinforcement layer (70) is as described in the insulation refractory reinforcement layer.

[0128] As shown in FIG. 8, when the fire-resistant coaxial cable (100) according to the present invention has a conductor fire-resistant reinforcement layer (70), the conductor fire-resistant reinforcement layer (70) as well as the insulator (20), the insulation fire-resistant reinforcement layer and the fire-resistant tape layer (60) additionally perform a fire-resistant function, so that the fire-resistant coaxial cable (100) according to the present invention has excellent fire resistance even at high temperatures of 1000°C or higher and can maintain the fire-resistant coaxial cable function for a certain period of time.

[0129] Furthermore, the conductor refractory reinforcement layer (70) can reinforce the insulation function of the inner conductor (10) by preventing a short circuit caused by mutual contact between the inner conductor (10) and the outer conductor (30) in addition to further improving the refractory performance of the cable.

[0130] The conductor refractory reinforcement layer (70) may include an insulating material having higher refractory performance than the refractory layer (23), and thus the temperature at which shape deformation occurs in a high-temperature environment may be higher. For example, even when the insulator (20) is deformed in an extreme situation of 1000°C or higher, the conductor refractory reinforcement layer (70) may be configured to space the inner conductor (10) and the outer conductor (30) so that the refractory coaxial cable (100) can maintain its cable function for a certain period of time.

[0131] Here, the fire-resistant coaxial cable (100) according to the present invention is presented as including all of a low-dielectric layer (50), an insulating fire-resistant reinforcement layer, a fire-resistant tape layer (60), and a conductor fire-resistant reinforcement layer (70), but in addition, it may be configured to include one or at least two or more of the low-dielectric layer (50), the insulating fire-resistant reinforcement layer, the fire-resistant tape layer (60), and the conductor fire-resistant reinforcement layer (70).

[0132] Figure 9 illustrates a cross-sectional view of another embodiment of a fire-resistant coaxial cable according to the present invention.

[0133] As illustrated in FIG. 9, the fire-resistant coaxial cable (100) according to the present invention is configured to include an inner conductor (10), an insulator (20), an outer conductor (30), and a cable jacket (40) similar to the embodiment illustrated in FIG. 4. However, in the embodiment illustrated in FIG. 9, the insulator (20) may be configured to include an insulating core (21`) and a fire-resistant layer (23`) that wraps the insulating core (21`) in the longitudinal direction. In addition, the insulating core (21`) may be configured to include a material other than glass yarn, and the fire-resistant layer (23`) may be configured to include a material other than refractory silicone rubber.

[0134] Specifically, the insulating core (21') of the insulator (20) includes flexible polyethylene having a low dielectric constant, and the refractory layer (23') of the insulator (20) can be formed by combining one or at least two high-refractory insulating materials selected from the group consisting of basalt fiber, mica tape, silica fiber, ceramic fiber, and glass fiber. Accordingly, an insulator (20) that can maintain refractory performance while implementing a low dielectric constant and flexibility can be formed.

[0135] When the above refractory layer (23') includes basalt fibers, the basalt fibers may be configured in a braided or coated form.

[0136] When the above refractory layer (23') includes glass fiber, it may be configured in the form of a tape or coated form of glass fiber.

[0137] The above-mentioned refractory layer (23') may be composed of a refractory material having high refractory properties that wraps the outer surface of the insulating core (21') in the longitudinal direction. The above-mentioned insulator (20) has a refractory layer (23') composed of one or at least two or more refractory insulating materials selected from among basalt fiber, mica tape, and glass fiber, so that even if the insulating core (21') having a relatively low melting point completely burns or melts at a high temperature, the refractory layer (23') arranged on the outside of the insulating core (21') can remain and perform its refractory function.

[0138] The fire-resistant coaxial cable according to the present embodiment may omit the low-dielectric constant layer (50) or the insulating refractory reinforcement layer (see FIGS. 6 to 8) provided on the outside of the insulator (20). This is because the insulating core (21') of the insulator (20) already contains polyethylene and thus may have a sufficiently low dielectric constant, and the refractory layer (23') is already composed of a high-refractory insulating material such as basalt fiber, mica tape, or glass fiber. In addition, the fire-resistant coaxial cable (100) according to the present embodiment applies a high-refractory insulating material to the refractory layer (23') of the insulator (20), as illustrated in FIG. 9, and further includes at least one of a refractory tape layer (60) wrapping the outer conductor (30) or a conductor refractory reinforcement layer (70) wrapping the inner conductor (10), thereby ensuring excellent fire resistance even at high temperatures of 1000°C or higher, thereby allowing the cable to maintain its function for a certain period of time.

[0139] The fire-resistant coaxial cable (100) according to the present invention can be applied to various environments such as specific fire-fighting objects requiring installation of wireless communication auxiliary equipment, other buildings, road tunnels, hazardous material storage and processing facilities, and underground facilities.

[0140]

[0141] [Example]

[0142]

[0143] 1. Manufacturing example

[0144]

[0145] Coaxial cable specimens were manufactured according to the design described in Table 1 below. Examples 1 to 4 and Comparative Examples 1 to 3 follow the structure of Fig. 5, with the inner conductor and outer conductor made of copper and the insulator made of silicone rubber and glass yarn as the refractory layer and the insulating core, respectively.

[0146]

[0147] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Inner conductor outer diameter (mm) 3.6 4.8 3.6 3.6 3.6 3.6 Insulator outer diameter (mm) 3.1 3.9 3.13 13 13 12.3 Insulator inclination angle (°) 40 45 20 60 10 7 0 40 Outer conductor corrugation shape Screw type Annular Screw type Annular Screw type Screw type

[0148]

[0149] 2. Physical property evaluation

[0150]

[0151] 1) Fire resistance evaluation

[0152] For each of the examples and comparative examples, a coaxial cable specimen (length: 1,200 mm) is installed horizontally on the ground on a support, and the jacket at both ends of the specimen is removed by about 100 mm. The inner conductor and the outer conductor are connected to a voltage application device so that they do not come into contact with each other. The center of the burner that applies the flame is positioned 70±10 mm below the bottom of the specimen, and the front of the burner and the central vertical plane of the specimen are separated by 45 mm. A flame of 750°C is applied for 90 minutes. The voltage must be maintained during the flame application, the inner conductor and the outer conductor must not be short-circuited, and the conductor must not be ruptured or disconnected.

[0153]

[0154] 2) Characteristic impedance evaluation

[0155] For each coaxial cable specimen (length: 100 m) of the examples and comparative examples, the characteristic impedance was measured by measuring the average value of the corresponding frequency in the frequency band of 30 to 1000 MHz using a measuring instrument (Network Analyzer), and it should be 45 to 55 Ω.

[0156]

[0157] 3) Flexibility evaluation

[0158] For each of the examples and comparative examples, the coaxial cable specimens were wound once on a circular mandrel with a diameter of 120 mm when the corrugation shape of the coaxial cable was spiral, and once on a circular mandrel with a diameter of 280 mm when the corrugation shape of the coaxial cable was annular, and the sensory workability of the worker was evaluated. If excessive force was required when winding once compared to a cable of similar size, it was evaluated as defective.

[0159]

[0160] 4) Structural stability (short) evaluation

[0161] For each of the examples and comparative examples, the coaxial cable specimens were wound once on a circular mandrel with a diameter of 120 mm when the corrugation shape of the coaxial cable was spiral, and once on a circular mandrel with a diameter of 280 mm when the corrugation shape of the coaxial cable was annular. A multimeter was connected to the inner conductor and the outer conductor to evaluate whether the inner conductor and the outer conductor were in contact, and if they were in contact, the specimen was evaluated as failing.

[0162]

[0163] The results of the above property evaluation are as described in Table 2 below.

[0164]

[0165] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Fire resistance characteristics Satisfactory Satisfactory Satisfactory Satisfactory Satisfactory Satisfactory Characteristics Impedance 52515350495640 Flexibility Good Good Good Good Good Poor Good Structural stability Pass Pass Pass Pass Fail Pass Pass Pass

[0166]

[0167] As described in Table 2 above, the coaxial cable specimens of Examples 1 to 4, in which the inclination angle and outer diameter of the insulator during lateral winding were precisely designed, were confirmed to have excellent fire resistance, characteristic impedance, flexibility, structural stability, etc. Meanwhile, the coaxial cable specimen of Comparative Example 1 suffered a short circuit due to contact between the inner and outer conductors during bending due to the inclination angle of the insulator falling below the standard during lateral winding, and the coaxial cable specimen of Comparative Example 2 suffered a characteristic impedance exceeding the standard, a decrease in flexibility, and an increase in manufacturing cost due to the inclination angle of the insulator exceeding the standard during lateral winding, and the coaxial cable specimen of Comparative Example 3 suffered a decrease in characteristic impedance due to insufficient gap between the inner and outer conductors due to the outer diameter of the insulator falling below the standard.

[0168] While this specification has described preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the claims below. Therefore, any modified implementation that fundamentally includes the elements of the claims should be considered within the technical scope of the present invention.

Claims

1. Internal conductor placed in the center; An insulator having fire-resistant properties and wound transversely on the outside of the inner conductor; An outer conductor that surrounds the outer side of the insulator and forms a coaxial structure with the inner conductor; and It comprises a cable jacket that wraps around the outside of the outer conductor; A fire-resistant coaxial cable, wherein the insulation has a dielectric constant of 2.7 to 9.0, an inclination angle of 20 to 60° during transverse winding, and an outer diameter of 75 to 98% of the outer diameter of the inner conductor.

2. In paragraph 1, A fire-resistant coaxial cable, characterized in that the outer diameter of the insulator is 75 to 95% of the outer diameter of the inner conductor.

3. In paragraph 1, A fire-resistant coaxial cable, characterized in that the insulator comprises a refractory elastomer material.

4. In paragraph 1, The above insulator has an insulating core and a refractory layer surrounding the insulating core, The above insulating core includes a tensile member, A fire-resistant coaxial cable, characterized in that the fire-resistant layer comprises a fire-resistant elastomer material.

5. In paragraph 3 or 4, A fire-resistant coaxial cable, characterized in that the above-mentioned fire-resistant elastomer material is silicone rubber.

6. In paragraph 4, A fire-resistant coaxial cable, characterized in that the tensile strength of the insulating core including the above tensile member is 5 g / TEX or more.

7. In paragraph 4, A fire-resistant coaxial cable, characterized in that the above tensile member comprises at least one of basalt fiber, glass fiber, silica fiber, ceramic fiber, or aramid fiber materials.

8. In paragraph 7, A fire-resistant coaxial cable, characterized in that the above tensile member includes glass yarn.

9. In paragraph 4, A fire-resistant coaxial cable, characterized in that the temperature at which the above insulating core undergoes shape deformation at a higher temperature than the above refractory layer.

10. In paragraph 1, Including a low-k dielectric layer surrounding the above insulator, A fire-resistant coaxial cable, characterized in that the dielectric constant of the low-k layer is 2.5 or less.

11. In paragraph 10, A fire-resistant coaxial cable, characterized in that the low-pass layer comprises at least one of PE (Polyethylene), HDPE (High-Density Polyethylene), PTFE (Polytetrafluoroethylene), and FEP (Fluorinated ethylene propylene).

12. In paragraph 1, A fire-resistant coaxial cable characterized by including an insulating refractory reinforcing layer that surrounds the above-mentioned insulator and reinforces the fire-resistant performance of the fire-resistant coaxial cable.

13. In paragraph 12, A fire-resistant coaxial cable, characterized in that the insulating refractory reinforcement layer comprises at least one of basalt fiber, silica fiber, ceramic fiber, glass fiber, and mica tape.

14. In paragraph 1, A fire-resistant coaxial cable characterized in that it further includes one or more fire-resistant tape layers wrapping the outer side of the outer conductor to enhance the fire-resistant performance of the fire-resistant coaxial cable.

15. In paragraph 14, A fire-resistant coaxial cable, characterized in that the above fire-resistant tape layer comprises at least one of a mica tape, a glass tape, and a metal tape.

16. In paragraph 1, A fire-resistant coaxial cable characterized in that it further includes a conductor fire-resistant reinforcing layer wrapping the outer side of the inner conductor to enhance the fire-resistant performance of the fire-resistant coaxial cable.

17. In paragraph 16, A fire-resistant coaxial cable, characterized in that the conductor refractory reinforcement layer comprises at least one of basalt fiber, silica fiber, ceramic fiber, glass fiber, and mica tape.

18. In paragraph 1, The above insulator includes an insulating core and a refractory layer surrounding the insulating core, The insulating core of the above insulator comprises polyethylene, A fire-resistant coaxial cable, characterized in that the fire-resistant layer of the above insulation comprises at least one of basalt fiber, silica fiber, ceramic fiber, glass fiber, and mica tape.

19. In paragraph 1, A fire-resistant coaxial cable, characterized in that the inner conductor and the outer conductor are made of copper or a copper alloy material.

20. In paragraph 1, A fire-resistant coaxial cable characterized in that the outer conductor has a corrugated pipe structure in which corrugated mountains and corrugated valleys are repeatedly formed.

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