Central tube optical cable

Abstract

This application relates to the field of optical cable technology, and more particularly to a central tube type optical cable. The central tube type optical cable includes a reinforcing core, an optical transmission unit, a heat transfer layer, an enhancement layer, and an outer sheath. The optical transmission unit is disposed on the outer periphery of the reinforcing core; the heat transfer layer is disposed on the outer periphery of the optical transmission unit and includes an oil reservoir and thermally conductive silicone oil filled in the oil reservoir; the enhancement layer is disposed on the outer periphery of the heat transfer layer; and the outer sheath is fitted on the outer periphery of the heat transfer layer. When the thermally conductive silicone oil flows from the inner oil cavity to the outer oil cavity, the high thermal conductivity of the thermally conductive silicone oil carries away the heat of the optical fiber; when the thermally conductive silicone oil flows from the outer oil cavity to the inner oil cavity, the low-temperature thermally conductive silicone oil on the outside flows back into the inner oil cavity, cooling the high-temperature optical fiber. This forms a heat dissipation and cooling cycle, effectively transferring the heat generated by the optical fiber or reinforcing core in a short time to the outside, avoiding permanent damage to the optical fiber due to excessive temperature.

Description

Technical Field

[0001] This application relates to the field of optical cable technology, and more particularly to a central tube type optical cable. Background Technology

[0002] Centralized tube optical cables are an important type of optical cable, occupying a vital position in modern communication and information technology. This type of cable features a unique design and superior performance. Historically, centralized tube optical cables gradually emerged against the backdrop of continuous development in optical fiber communication technology. Since the application of the first practical multimode optical cable in China in 1982, China's optical cable manufacturing and industrialization have undergone decades of development. During this process, centralized tube optical cables, as an important type of optical cable, have been widely used and developed.

[0003] Currently, under certain special circumstances, central tube optical cables can generate a large amount of heat in a short period of time, leading to overheating and damage. For example, the reinforcing core of the optical cable may be electrified. When the reinforcing core is energized, it will generate heat. For instance, 1 second after being energized, the current in a 100m optical cable reaches 24A, generating 5.518KJ of heat. The temperature in the eddy current region can rapidly rise to 406.1℃ within 18 minutes. Alternatively, if the signal transmission volume or current carried by the optical cable exceeds its designed allowable current carrying capacity, it will also cause the optical cable to generate a large amount of heat in a short period of time. If the heat cannot be dissipated in time, it will lead to damage to the optical cable. Summary of the Invention

[0004] This application provides a central tube optical cable to solve the problem that, under certain special circumstances, the central tube optical cable in the prior art will generate a large amount of heat in a short time, causing the optical cable to overheat and be damaged.

[0005] This application provides a central tube type optical cable, comprising:

[0006] Reinforced core;

[0007] The optical transmission unit is located on the outer periphery of the reinforcing core;

[0008] A heat transfer layer is disposed on the outer periphery of the optical transmission unit. The heat transfer layer includes an oil reservoir and thermally conductive silicone oil filled in the oil reservoir.

[0009] A reinforcement layer is disposed on the outer periphery of the heat transfer layer;

[0010] The outer sheath is fitted around the periphery of the reinforcing layer.

[0011] In one possible design, the oil storage pipe has a double-walled structure, which includes an inner wall, an outer wall, and a central wall. An inner oil cavity is formed between the inner wall and the central wall, and an outer oil cavity is formed between the outer wall and the central wall. A forward oil hole and a reverse oil hole are provided on the central wall, and the thermally conductive silicone oil can flow between the inner and outer oil cavities through the forward and reverse oil holes.

[0012] In one possible design, an expansion body is provided in the inner oil cavity. The volume of the expansion body can expand when the temperature is higher than a preset temperature. The thermally conductive silicone oil that squeezes the inner oil cavity flows into the outer oil cavity through the forward oil hole, and the thermally conductive silicone oil in the outer oil cavity flows into the inner oil cavity through the reverse oil hole.

[0013] In one possible design, the expander includes a flexible outer shell and an expanded core material, which is a fluorinated liquid or expanded graphite.

[0014] In one possible design, the expansion bodies are spaced circumferentially along the inner tube wall.

[0015] In one possible design, forward oil holes and reverse oil holes are spaced circumferentially along the central pipe wall.

[0016] In one possible design, the forward oil hole and the reverse oil hole are respectively provided with:

[0017] The adapter has a horn-shaped flow channel inside, and the small end of the horn-shaped flow channel has a flat opening.

[0018] The extension tube is connected to the flat opening, and the inner walls of the extension tubes abut against each other to achieve closure.

[0019] In one possible design, the optical transmission unit includes an optical fiber, an inner sheath, and fiber grease. The inner sheath is fitted around the outer periphery of the optical fiber, and fiber grease is coated between the inner sheath and the optical fiber.

[0020] In one possible design, the enhancement layer includes:

[0021] Non-metallic yarn, twisted around the outer periphery of the heat transfer layer;

[0022] The strap is fitted around the outer periphery of the non-metallic yarn;

[0023] Water-blocking tape is fitted around the outer perimeter of the wrapping tape;

[0024] The reinforcing member is embedded in the outer sheath along the axial direction of the outer sheath.

[0025] In one possible design, water-blocking yarn is also included, which is twisted around the periphery of the optical transmission unit.

[0026] The beneficial effects of this application are as follows:

[0027] The central tube optical cable of this application uses an oil storage tube installed around the outer periphery of the optical fiber and the reinforcing core. Both the inner and outer oil cavities of the oil storage tube are filled with thermally conductive silicone oil. When the thermally conductive silicone oil flows from the inner oil cavity to the outer oil cavity, its high thermal conductivity carries away the heat from the optical fiber. When the thermally conductive silicone oil flows from the outer oil cavity to the inner oil cavity, the low-temperature thermally conductive silicone oil on the outside flows back into the inner oil cavity, cooling the high-temperature optical fiber. This forms a heat dissipation and cooling cycle, effectively transferring the heat generated by the optical fiber or reinforcing core in a short time to the outside, and preventing the optical fiber from being permanently damaged due to excessive temperature. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of the central tube optical cable provided in the embodiments of this application;

[0030] Figure 2 A schematic diagram of the heat transfer layer of the central tube optical cable provided in this application under normal temperature conditions;

[0031] Figure 3 A schematic diagram of the heat transfer layer of the central tube optical cable provided in this application under an abnormal temperature rise state;

[0032] Figure 4 This is a schematic diagram of the structure of the central tube optical cable provided in the embodiments of this application, showing the forward and reverse oil holes in closed states;

[0033] Figure 5 This is a schematic diagram of the structure of the central tube optical cable with the forward and reverse oil holes open, as provided in the embodiments of this application.

[0034] Figure label:

[0035] 100. Reinforcing core; 200. Optical transmission unit; 210. Optical fiber; 220. Inner sheath; 300. Heat transfer layer; 310. Oil reservoir; 311. Inner tube wall; 312. Outer tube wall; 313. Central tube wall; 314. Inner oil cavity; 315. Outer oil cavity; 316. Forward oil hole; 317. Reverse oil hole; 320. Thermally conductive silicone oil; 330. Expansion body; 331. Flexible outer shell; 332. Expansion core material; 400. Reinforcing layer; 410. Non-metallic yarn; 420. Wrapping tape; 430. Water-blocking tape; 440. Reinforcing component; 450. Water-blocking yarn; 500. Outer sheath; 610. Adapter; 620. Extension tube. Detailed Implementation

[0036] The technical solutions of this application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0037] The following is combined Figures 1-5 This describes the central tube optical cable provided in the embodiments of this application.

[0038] Reference Figure 1 As shown, the central tube optical cable provided in this application embodiment includes a reinforcing core 100, an optical transmission unit 200, a heat transfer layer 300, an enhancement layer 400, and an outer sheath 500. The optical transmission unit 200 is disposed on the outer periphery of the reinforcing core 100, the heat transfer layer 300 is disposed on the outer periphery of the optical transmission unit 200, the enhancement layer 400 is disposed on the outer periphery of the heat transfer layer 300, and the outer sheath 500 is sleeved on the outer periphery of the enhancement layer 400.

[0039] The reinforcing core 100 is located at the center of the optical cable. The reinforcing core 100 can be made of a single steel wire, steel strand, or fiber-reinforced plastic. It is used to fix other structures of the optical cable and enhance the tensile and compressive strength of the optical cable.

[0040] Multiple optical transmission units 200 are circumferentially twisted around the outer periphery of the reinforcing core 100. Each optical transmission unit 200 includes an optical fiber 210, an inner sheath 220, and fiber optic grease. The optical fiber 210 is a single-mode or multimode optical fiber. The inner sheath 220 is fitted around the outer periphery of the optical fiber 210. The material of the inner sheath 220 is polyvinyl chloride or low-smoke halogen-free polyolefin, which is lightweight, moisture-proof, flame-retardant, and has good stability and dielectric properties. It can protect the internal optical fiber 210, giving the optical cable high bending strength and impact toughness during the laying process. A fiber grease is coated between the inner sheath 220 and the optical fiber 210. The fiber grease is a viscous semi-solid substance formed by dispersing one or more gelling agents in one or more base oils. By coating the inner sheath 220 and the optical fiber 210 with fiber grease, a waterproof and moisture-proof sealing effect can be achieved. At the same time, it plays a buffering role during the manufacturing and use of the optical cable, which can reduce the stress loss of the optical fiber 210 under mechanical stress and improve the transmission stability and reliability of the optical fiber 210 optical cable.

[0041] The heat transfer layer 300 is sleeved on the outer periphery of all inner sheaths 220. The heat transfer layer 300 includes an oil storage tube 310 and thermally conductive silicone oil 320 filled in the oil storage tube 310. The silicone oil has high heat resistance, electrical insulation and physiological inertness. The high thermal conductivity of the thermally conductive silicone oil 320 can timely conduct the heat generated by the optical fiber 210 or the reinforcing core 100 to the outside of the optical cable.

[0042] Reference Figure 2 As shown, in some specific embodiments, the oil storage pipe 310 has a double-walled structure, including an inner pipe wall 311, an outer pipe wall 312, and a central pipe wall 313. An inner oil cavity 314 is formed between the inner pipe wall 311 and the central pipe wall 313, and an outer oil cavity 315 is formed between the outer pipe wall 312 and the central pipe wall 313. Thermally conductive silicone oil 320 is filled in the inner oil cavity 314 and the outer oil cavity 315 respectively. The inner pipe wall 311, the outer pipe wall 312, and the central pipe wall 313 are made of polybutylene terephthalate or modified polypropylene, which has a high modulus and good toughness, enabling it to withstand large oil pressure loads without deformation. The central tube wall 313 is provided with a forward oil hole 316 and a reverse oil hole 317. Under normal conditions, both the inner oil cavity 314 and the outer oil cavity 315 are filled with thermally conductive silicone oil 320, ensuring that the oil pressure in the inner oil cavity 314 and the outer oil cavity 315 is equal. When the oil pressure is equal, both the forward oil hole 316 and the reverse oil hole 317 are closed. When the oil pressure in the inner oil cavity 314 is higher, the thermally conductive silicone oil 320 in the inner oil cavity 314 can flow to the outer oil cavity 315 through the forward oil hole 316; when the oil pressure in the outer oil cavity 315 is higher, the thermally conductive silicone oil 320 in the outer oil cavity 315 can flow to the inner oil cavity 314 through the reverse oil hole 317.

[0043] An expansion body 330 is provided in the inner oil cavity 314. The volume of the expansion body 330 can expand when the temperature is higher than the preset temperature. The typical operating temperature range of ordinary optical cables is -40℃ to 70℃. When the temperature is higher than 70℃, the optical fiber 210 material thermally expands, and at the same time, the refractive index of the optical fiber 210 changes, which causes the optical signal transmission path to change and causes signal distortion. Therefore, the expansion initiation temperature of the expander 330 can be set to 50-70℃. For example, if the expansion initiation temperature of the expander 330 is 60℃, when the temperature of the thermally conductive silicone oil 320 in the inner oil cavity 314 reaches 60℃, the expander 330 begins to expand rapidly, causing the oil pressure in the inner oil cavity 314 to increase rapidly. Under the squeezing action of the oil pressure, the high-temperature thermally conductive silicone oil 320 in the inner oil cavity 314 opens the forward oil hole 316 and flows into the outer oil cavity 315. At the same time, due to the inflow of the high-temperature thermally conductive silicone oil 320, the oil pressure in the outer oil cavity 315 will also increase rapidly until the oil pressure in the outer oil cavity 315 is higher than that in the inner oil cavity 314. Then, the low-temperature thermally conductive silicone oil 320 in the outer oil cavity 315 opens the reverse oil hole 317 and flows into the inner oil cavity 314. In this way, a heat dissipation and cooling cycle is formed between the inner oil cavity 314 and the outer oil cavity 315, which effectively transfers the heat generated by the optical fiber 210 or the reinforcing core 100 in a short time to the outside, avoiding permanent damage caused by excessive temperature of the optical fiber 210.

[0044] The expansion body 330 includes a flexible outer shell 331 and an expansion core material 332. The flexible outer shell 331 can be made of silicone film or polyurethane elastomer film, which has high elasticity. The expansion core material 332 can be made of fluorinated liquid or expanded graphite. For example, it can be "OPTEON SF70," a fluorinated liquid product developed by Chemours Chemicals, which has a boiling point of 70°C, is non-flammable, and has stable chemical properties. When the temperature is above 70°C, the liquid turns into a gas, thereby gradually expanding the flexible outer shell 331 and achieving rapid expansion. When the temperature returns to normal, it turns back into a liquid, and the oil pressure in the inner oil cavity 314 and the outer oil cavity 315 returns to an equal state. Alternatively, it can be made of expanded graphite, which is a loose and porous worm-like material obtained by intercalation, washing, drying, and high-temperature expansion of natural graphite flakes. When the temperature is above 60°C, the expanded graphite begins to expand, changing from a sheet shape to a worm shape, and its volume gradually increases, thereby gradually expanding the flexible outer shell 331 and achieving rapid expansion. When the temperature recovers, its volume gradually returns to its original state, and the oil pressure in the inner oil cavity 314 and the outer oil cavity 315 returns to equal, thus ensuring sustainable recycling.

[0045] Reference Figure 2 , Figure 3As shown, in some specific embodiments, the expansion body 330 has a curved structure, and multiple expansion bodies 330 are arranged circumferentially along the inner tube wall 311 to form a group of expansion bodies 330. Specifically, the group of expansion bodies 330 are connected by a ring cable, and elastic sleeves are provided at intervals on the ring cable. The outer surface of the flexible outer shell 331 has an annular groove. When the expansion body 330 is not expanded, the elastic sleeve can be tightly clamped in the annular groove to prevent the expansion body 330 from shifting. This ensures that when the temperature of the optical fiber 210 rises in any direction, the expansion body 330 at the corresponding position can be quickly triggered to expand, squeezing out the high-temperature thermally conductive silicone oil 320 at that location and allowing the low-temperature thermally conductive silicone oil 320 to flow in, thereby dissipating heat in a timely manner.

[0046] Reference Figure 2 , Figure 3 As shown, in some specific embodiments, forward oil holes 316 and reverse oil holes 317 are arranged circumferentially along the central tube wall 313. Specifically, one end of the expansion body 330 is provided with a forward oil hole 316 and the other end is provided with a reverse oil hole 317. In this way, when any expansion body 330 begins to expand, a circulation path can be formed between two adjacent forward oil holes 316 and reverse oil holes 317, thereby accelerating the flow of thermally conductive silicone oil 320 in the inner oil cavity 314 and the outer oil cavity 315, allowing the thermally conductive silicone oil 320 at lower temperatures to flow quickly to higher temperatures, thus accelerating the heat dissipation and cooling cycle.

[0047] Reference Figure 4 , Figure 5 As shown, in some specific embodiments, a connector 610 and an extension tube 620 are respectively provided at the forward oil hole 316 and the reverse oil hole 317. The interior of the connector 610 forms a horn-shaped flow channel. The large end of the horn-shaped flow channel is connected to the forward oil hole 316 / reverse oil hole 317 on the central tube wall 313, and the small end of the horn-shaped flow channel forms a flat opening. The extension tube 620 is connected to the flat opening. The two sides of the extension tube 620 have symmetrical creases. When the oil pressure of the inner oil cavity 314 and the outer oil cavity 315 are equal, the extension tube 620 is folded along the creases into a sheet shape, so that its inner walls abut against each other to close the forward oil hole 316 / reverse oil hole 317. When the oil pressure of the inner oil cavity 314 and the outer oil cavity 315 are not equal, the thermally conductive silicone oil 320 will be ejected from the side with higher oil pressure, opening the extension tube 620 into an elliptical shape and opening the forward oil hole 316 / reverse oil hole 317.

[0048] Reference Figure 1As shown, in some specific embodiments, the reinforcing layer 400 includes non-metallic yarn 410, wrapping tape 420, water-blocking tape 430, a sheath, and water-blocking yarn 450. The non-metallic yarn 410 is twisted around the outer periphery of the heat transfer layer 300. The non-metallic yarn 410 is aramid yarn, which has high strength and high modulus; its strength is 5-6 times that of steel wire, and its modulus is also very high, significantly improving the tensile strength of the optical cable. The wrapping tape 420 is fitted around the outer periphery of the non-metallic yarn 410. The wrapping tape 420 is FRP tape, preventing the optical fiber 210, reinforcing member 440, etc., in the cable core from adhering to the outer sheath 500, and also preventing electromagnetic interference. The water-blocking tape 430 is fitted around the outer periphery of the wrapping tape 420, serving as a moisture-proof and water-resistant barrier. The outer sheath 500 is fitted around the outer periphery of the water-blocking tape 430. The outer sheath 500 is made of polyethylene, thus providing protective covering for the internal structure of the optical cable. The reinforcing member 440 is embedded in the outer sheath 500 along the axial direction of the outer sheath 500. The reinforcing member 440 is a steel wire or FRP rod, which improves the tensile and compressive strength of the optical cable. A water-blocking yarn 450 is also provided between the inner tube wall 311 and the inner sheath 220. The water-blocking yarn 450 is twisted around the outer periphery of the inner sheath 220 to further prevent moisture from intruding into and spreading into the inner sheath 220.

[0049] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0050] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0051] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between components; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0052] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0053] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A central tube type optical cable, characterized in that, include: Reinforced core; The optical transmission unit is disposed on the outer periphery of the reinforcing core; A heat transfer layer is disposed on the outer periphery of the optical transmission unit, and the heat transfer layer includes an oil storage tube and thermally conductive silicone oil filled in the oil storage tube; A reinforcement layer is disposed on the outer periphery of the heat transfer layer; An outer sheath is fitted around the outer periphery of the reinforcing layer; The oil storage pipe has a double-walled structure, comprising an inner wall, an outer wall, and a central wall. An inner oil cavity is formed between the inner wall and the central wall, and an outer oil cavity is formed between the outer wall and the central wall. A forward oil hole and a reverse oil hole are provided on the central wall, allowing the thermally conductive silicone oil to flow between the inner and outer oil cavities through the forward and reverse oil holes. An expander is provided in the inner oil cavity. The volume of the expander can expand when the temperature is higher than a preset temperature. The thermally conductive silicone oil squeezed into the inner oil cavity flows into the outer oil cavity through the forward oil hole, and the thermally conductive silicone oil in the outer oil cavity flows into the inner oil cavity through the reverse oil hole.

2. The central tube optical cable according to claim 1, characterized in that: The expander includes a flexible outer shell and an expandable core material, wherein the expandable core material is a fluorinated liquid or expanded graphite.

3. The central tube optical cable according to claim 1, characterized in that: The expansion bodies are arranged at circumferential intervals along the inner tube wall.

4. The central tube optical cable according to any one of claims 1-3, characterized in that: The forward oil holes and the reverse oil holes are spaced apart circumferentially along the central pipe wall.

5. The central tube optical cable according to any one of claims 1-3, characterized in that, The forward oil hole and the reverse oil hole are respectively provided with: The adapter has a horn-shaped flow channel inside, and the small end of the horn-shaped flow channel has a flat opening. An extension tube is connected to the flat opening, and the inner walls of the extension tubes abut against each other to achieve closure.

6. The central tube optical cable according to any one of claims 1-3, characterized in that: The optical transmission unit includes an optical fiber, an inner sheath, and fiber grease. The inner sheath is fitted around the outer periphery of the optical fiber, and fiber grease is coated between the inner sheath and the optical fiber.

7. The central tube optical cable according to any one of claims 1-3, characterized in that: The enhancement layer includes: Non-metallic yarn is twisted around the outer periphery of the heat transfer layer; A strap is fitted around the outer periphery of the non-metallic yarn; Water-blocking tape is fitted around the outer periphery of the wrapping tape; The reinforcing member is embedded in the outer sheath along the axial direction of the outer sheath.

8. The central tube optical cable according to any one of claims 1-3, characterized in that: It also includes water-blocking yarn, which is twisted around the outer periphery of the optical transmission unit.

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