All-dielectric self-supporting aerial optical cable

Abstract

The present application relates to an all-dielectric self-supporting aerial optical cable, comprising a cable core, an inner sheath, a non-metallic reinforcing layer, and an outer sheath that are sequentially arranged from inside to outside; the cable core comprises a plurality of micro-bundled tubes stranded into an integral body; a rigid non-metallic reinforcing member is embedded in the inner sheath; the non-metallic reinforcing layer is stranded on the outer periphery of the inner sheath; and the outer sheath covers the non-metallic reinforcing layer. In the optical cable provided by the present application, under the clamping of a fitting, a clamping force on the outer sheath can be directly conducted to the non-metallic reinforcing layer between the inner sheath and the outer sheath, and the non-metallic reinforcing layer then transmits the clamping force to the rigid non-metallic reinforcing member by means of the inner sheath, so as to implement effective transmission of the clamping force, so that the rigid non-metallic reinforcing member can fully play a tensile role, thereby ensuring that the optical cable provided in the embodiments of the present application can be applied not only to small spans and relatively mild meteorological conditions, but also to medium-long spans and extreme meteorological conditions.

Description

A self-supporting all-dielectric overhead optical cable Technical Field

[0001] This application relates to the field of optical fiber and cable technology, and in particular to an all-dielectric self-supporting overhead optical cable. Background Technology

[0002] All-dielectric self-supporting aerial optical cables, due to their all-dielectric and self-supporting advantages, can be laid directly using existing utility poles. Compared to methods such as ducting or direct burial, this type of optical cable offers lower construction costs and greater ease of installation.

[0003] All-dielectric self-supporting optical cables using micro-tubes as optical units benefit from the compact structure and small size of the micro-tubes, resulting in small outer diameter and light weight, making them suitable for aerial applications. Furthermore, the flexible texture and ease of stripping of the micro-tubes greatly facilitate fiber coiling and fiber splicing operations within junction boxes and fiber distribution boxes.

[0004] On the other hand, microtubes also have some shortcomings:

[0005] (1) The wall of the microtube is almost in close contact with the internal optical fiber, and the optical fiber does not have enough space to form excess length inside the microtube.

[0006] (2) The walls of microtubes are thin and soft, making them less resistant to external mechanical damage.

[0007] Self-supporting aerial optical cables rely on their own tensile strength components to withstand long-term stress and the effects of wind and ice loads. Conventional self-supporting aerial optical cables using micro-tubes as optical units pose significant application risks in areas with medium to long spans and frequent extreme weather conditions. The main reason is that self-supporting aerial optical cables typically use pre-twisted wires or wedge-shaped clamping hardware for installation. Optical cables using micro-tubes as optical units have a loose internal structure, with the micro-tubes and non-metallic reinforcing layer integrated. When using the aforementioned hardware, it is difficult to fully transfer the clamping force on the sheath to the non-metallic reinforcing layer inside the cable. Therefore, this type of optical cable can only be used for short spans and relatively mild weather conditions. Summary of the Invention

[0008] This application provides a self-supporting all-dielectric aerial optical cable to solve the problem in related technologies where it is difficult to fully transmit the clamping force on the sheath to the non-metallic reinforcing layer inside the optical cable when using hardware, which limits its application to small spans and relatively mild weather conditions.

[0009] This application provides a fully dielectric self-supporting overhead optical cable, which includes a cable core, an inner sheath, a non-metallic reinforcing layer and an outer sheath arranged sequentially from the inside to the outside.

[0010] The cable core comprises several microtubes stranded together.

[0011] The inner sheath is embedded with a rigid non-metallic reinforcing member;

[0012] The non-metallic reinforcing layer is twisted to the outer periphery of the inner sheath;

[0013] The outer sheath covers the non-metallic reinforcing layer.

[0014] In some embodiments, the non-metallic reinforcing layer is made of aramid or fiberglass yarn, which is twisted to the outer periphery of the inner sheath in a unidirectional or bidirectional twisting manner.

[0015] In some embodiments, the outer sheath is configured such that a stripping force of not less than 600N is required to strip a 30cm length of the outer sheath longitudinally.

[0016] In some embodiments, an anti-adhesion isolation layer is provided between the inner sheath and the cable core, and the anti-adhesion isolation layer is located on the inner wall of the inner sheath.

[0017] In some embodiments, the material of the anti-sticking barrier layer includes one or more of aramid, fiberglass yarn, polyester tape, and nonwoven fabric.

[0018] In some embodiments, the cross-sectional area of ​​the cable core accounts for 40% to 70% of the cross-sectional area inside the anti-adhesion insulating layer.

[0019] In some embodiments, the stranding pitch H of the non-metallic reinforcing layer satisfies:

[0020] H = D × π × K;

[0021] D is the outer diameter of the inner sheath, and K is the twisting coefficient, 15≤K≤45.

[0022] In some embodiments, the cable core further includes a water-blocking material, which is disposed between the microtube bundles.

[0023] In some embodiments, the water-blocking material includes one or more of water-blocking yarn and water-blocking powder.

[0024] In some embodiments, the microtube is made of one of thermoplastic polyester elastomer, thermoplastic elastomer, polyurethane, and polyolefin.

[0025] And / or, the optical fiber in the micro-tube is provided with a water-blocking material, which includes one or more of water-blocking yarn, water-blocking powder and water-blocking fiber paste;

[0026] And / or, the number of optical fibers in the micro-bundle tube is 1 to 24;

[0027] And / or, the number of micro-tube bundles is 1 to 48, and multiple micro-tube bundles are arranged in an orderly manner by SZ twisting or unidirectional twisting and loosely bundled by tie yarn;

[0028] And / or, the inner sheath is made of one of polyethylene or low-smoke halogen-free flame-retardant polyolefin.

[0029] And / or, the rigid non-metallic reinforcing member is made of one of glass fiber reinforced plastic rods or aramid reinforced plastic rods;

[0030] And / or, the diameter of the rigid non-metallic reinforcing member is 0.5 to 2.5 mm;

[0031] And / or, the number of the rigid non-metallic reinforcing members is even, and they are symmetrically distributed on both sides of the inner sheath;

[0032] And / or, the cross-sectional area of ​​the cable core accounts for 40% to 70% of the cross-sectional area inside the inner sheath.

[0033] The beneficial effects of the technical solution provided in this application include:

[0034] This application employs a double-layer sheath structure. A rigid non-metallic reinforcing member is embedded within the inner sheath. This rigid non-metallic reinforcing member enables the inner sheath to maintain relative dimensional stability under temperature changes and external mechanical forces. The non-metallic reinforcing layer is twisted onto the outer wall of the inner sheath, and then tightly wrapped with an outer sheath, forming a tightly connected integral structure of the inner sheath, the non-metallic reinforcing layer, and the outer sheath. Under the clamping of the fittings, the clamping force on the outer sheath can be directly transmitted to the non-metallic reinforcing layer between the inner and outer sheaths. The non-metallic reinforcing layer then transmits the clamping force through the inner sheath to the rigid non-metallic reinforcing member, achieving effective transmission of clamping force. This allows the rigid non-metallic reinforcing member to fully perform its tensile function, thereby ensuring that the optical cable provided in this application embodiment can be applied not only to short spans and relatively mild weather conditions, but also to medium and long spans and extreme weather conditions. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 is a schematic diagram of the all-dielectric self-supporting overhead optical cable provided in the embodiment of this application.

[0037] In the diagram: 1. Microtube bundle; 2. Water-blocking material; 3. Anti-sticking isolation layer; 4. Rigid non-metallic reinforcement; 5. Inner sheath; 6. Non-metallic reinforcement layer; 7. Outer sheath. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. 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.

[0039] Referring to Figure 1, this application embodiment provides an all-dielectric self-supporting overhead optical cable, which includes, from the inside out, a cable core, an inner sheath 5, a non-metallic reinforcing layer 6, and an outer sheath 7. The cable core in this application includes several micro-tube bundles 1 twisted together. The inner sheath 5 is embedded with a rigid non-metallic reinforcing member 4. The non-metallic reinforcing layer 6 is twisted around the outer periphery of the inner sheath 5. The outer sheath 7 covers the non-metallic reinforcing layer 6.

[0040] This application adopts a double-layer sheath structure. A rigid non-metallic reinforcing member 4 is embedded in the inner sheath 5. The rigid non-metallic reinforcing member 4 enables the inner sheath 5 to maintain relative dimensional stability under the influence of temperature changes and external mechanical forces. The non-metallic reinforcing layer 6 is twisted onto the outer wall of the inner sheath 5, and then tightly wrapped with an outer sheath 7, so that the inner sheath 5, the non-metallic reinforcing layer 6 and the outer sheath 7 form a tightly connected integral structure. Under the clamping of the fittings, the clamping force on the outer sheath 7 can be directly transmitted to the non-metallic reinforcing layer 6 between the inner sheath 5 and the outer sheath 7. The non-metallic reinforcing layer 6 then transmits the clamping force through the inner sheath 5 to the rigid non-metallic reinforcing member 4, realizing the effective transmission of clamping force. This allows the rigid non-metallic reinforcing member 4 to fully play its tensile role, thereby ensuring that the optical cable provided in this embodiment can be applied not only to short spans and relatively mild weather conditions, but also to medium and long spans and extreme weather conditions.

[0041] In this application, the material of the non-metallic reinforcing layer 6 includes aramid or glass fiber yarn, and the aramid or glass fiber yarn is twisted to the outer periphery of the inner sheath 5 in a unidirectional or bidirectional twisting manner.

[0042] The outer sheath 7 tightly covers the outer periphery of the non-metallic reinforcing layer 6. The outer sheath 7 can be made of common materials such as polyethylene. The outer sheath 7 must have sufficient covering force to transmit the clamping force to the inner non-metallic reinforcing layer 6 and the rigid non-metallic reinforcing member 4 inside the inner sheath 5 when subjected to hardware clamping. Therefore, this application specifies the covering condition of the outer sheath 7; specifically, the outer sheath 7 is configured such that the peeling force required to longitudinally peel off a 30cm length of the outer sheath is not less than 600N.

[0043] To prevent the micro-tube 1 from sticking to the inner wall of the inner sheath 5 and causing optical cable attenuation, as shown in Figure 1, an anti-sticking isolation layer 3 is provided between the inner sheath 5 and the cable core. The anti-sticking isolation layer 3 is located on the inner wall of the inner sheath 5.

[0044] In this application, the material of the anti-sticking isolation layer 3 includes one or more of aramid, fiberglass yarn, polyester tape and non-woven fabric.

[0045] In this application, in order to allow the micro-tube 1 to have a certain amount of room to move, the cross-sectional area of ​​the cable core accounts for 40% to 70% of the cross-sectional area inside the anti-adhesion isolation layer 3.

[0046] It is understandable that when the anti-sticking isolation layer 3 is not added, the cross-sectional area of ​​the cable core accounts for 40% to 70% of the cross-sectional area inside the inner sheath 5.

[0047] Because this application features a double-sheath structure, the clamping force applied to the outer sheath 7 by the hardware must pass through the non-metallic reinforcing layer 6 to be transmitted to the inner sheath 5. The non-metallic reinforcing layer 6 is typically made of aramid or fiberglass yarn, which is relatively soft. During manufacturing or use, this may result in force loss or prevent the transfer of the clamping force to the inner sheath 5. Consequently, the rigid non-metallic reinforcing member 4 cannot perform its work, leading to inconsistent elongation of the inner and outer sheaths, stress accumulation, and even phenomena such as pull-out or delamination of the outer sheath 7, affecting the performance of the optical cable. Therefore, this application optimizes the stranding pitch of the non-metallic reinforcing layer 6, ensuring it tightly wraps around the outer periphery of the inner sheath 5, thereby achieving effective force transmission.

[0048] Specifically, the twist pitch H of the non-metallic reinforcing layer 6 satisfies: H=D×π×K;

[0049] D is the outer diameter of the inner sheath 5, and K is the twisting coefficient, 15≤K≤45.

[0050] The reason for using the outer diameter D of the inner sheath 5 as a basis to limit the stranding pitch H of the non-metallic reinforcing layer 6 is to alleviate phenomena such as pull-out and delamination of the outer sheath 7 of the optical cable and to achieve effective force transmission.

[0051] The inner sheath 5, supported by rigid non-metallic reinforcing elements 4, is highly rigid and exhibits virtually no shrinkage. During the outer sheath process, non-metallic reinforcing layers 6, such as aramid yarn or glass yarn, are wrapped around the inner sheath 5 and then together covered by the outer sheath 7. During the molding and cooling process, the outer sheath 7 shrinks dramatically, causing the yarn-like elements to shrink as well. This results in the yarn-like elements not being fully straightened between the inner and outer sheaths 5 and 7. Consequently, when this portion of the yarn is subjected to tension, it must first straighten before bearing the force, significantly reducing the yarn's tensile strength.

[0052] The yarn-like element is wrapped around the inner sheath 5, which has strong rigid support, with an appropriate twisting pitch. This creates friction between the yarn-like element and the inner sheath 5 due to the winding effect, greatly reducing the impact of the outer sheath 7's shrinkage on the yarn length. If the twisting pitch of the yarn-like element is too large, the winding effect is insufficient, making it difficult to resist the shrinkage of the outer sheath 7. If the pitch is too small, the yarn will be too tightly wound, resulting in excessive length, which also makes it difficult to provide sufficient tensile strength.

[0053] By setting a suitable stranding pitch, the yarn length can be made as close as possible to the optical cable length, thereby fully leveraging the tensile strength of the reinforcing element.

[0054] Extensive experiments have shown that by limiting the twist pitch H of the non-metallic reinforcing layer 6 as described above, effective force transmission can be achieved.

[0055] Referring to Figure 1, in this application, the cable core further includes a water-blocking material 2, which is disposed between the micro-tube bundles 1. The water-blocking material 2 includes one or more of water-blocking yarn and water-blocking powder.

[0056] In some preferred embodiments, the microtube 1 is made of one of thermoplastic polyester elastomer, thermoplastic elastomer, polyurethane, and polyolefin.

[0057] In some preferred embodiments, a water-blocking material 2 is disposed in the optical fiber inside the micro-tube 1, and the water-blocking material 2 includes one or more of water-blocking yarn, water-blocking powder and water-blocking fiber paste.

[0058] In some preferred embodiments, the number of optical fibers in the micro-bundle tube 1 is 1 to 24.

[0059] In some preferred embodiments, the number of micro-tube bundles 1 is 1 to 48, and the multiple micro-tube bundles 1 are arranged in an orderly manner by SZ twisting or unidirectional twisting and loosely bundled by yarn binding.

[0060] In some preferred embodiments, the inner sheath 5 is made of polyethylene or low-smoke halogen-free flame-retardant polyolefin.

[0061] In some preferred embodiments, the rigid non-metallic reinforcing member 4 is made of either glass fiber reinforced plastic rod or aramid reinforced plastic rod.

[0062] In some preferred embodiments, the diameter of the rigid non-metallic reinforcing member 4 is 0.5 to 2.5 mm.

[0063] In some preferred embodiments, the number of the rigid non-metallic reinforcing members 4 is even, such as two or four, and they are symmetrically distributed on both sides of the inner sheath 5.

[0064] Example 1

[0065] A self-supporting all-dielectric overhead optical cable comprises a micro-bubble tube 1, a water-blocking material 2, an anti-sticking isolation layer 3, an inner sheath 5, a non-metallic reinforcing layer 6, and an outer sheath 7.

[0066] Water-blocking material 2 is made of water-blocking yarn, anti-sticking isolation layer 3 is made of water-blocking tape, and non-metallic reinforcing layer 6 is made of aramid fiber.

[0067] This optical cable structure is suitable for spans of up to 150m. Compared to the traditional micro-tube with a span of 70m, this structure increases the span by more than double.

[0068] The bundle consists of 24 microtubes 1, each containing 12 optical fibers. The gaps between the optical fibers inside the microtubes are filled with fiber grease. The 24 microtubes 1 are unidirectionally twisted together to form a single bundle. Water-blocking material 2 fills the spaces between the microtubes.

[0069] The anti-adhesion isolation layer 3 longitudinally encloses the bundled microtubes 1 and water-blocking material 2. The circular cross-sectional area enclosed by the anti-adhesion isolation layer 3 is twice the sum of the cross-sectional areas of the microtubes 1 and the water-blocking material 2.

[0070] The inner sheath 5 covers the aforementioned water-blocking tape. Four GFRP (fluorinated fiber reinforced polymer) strips (GFRP) with a diameter of 1.6 mm are embedded inside the inner sheath, arranged in two symmetrical groups. To ensure the GFRP can function effectively under stress, the minimum thickness of the sheath surrounding the GFRP is 0.3 mm. Using four 1.6 mm GFRP strips, compared to two 2.0 mm GFRP strips, allows for a smaller outer diameter of the optical cable while enabling it to withstand greater forces and achieve better tensile strength.

[0071] A portion of aramid fibers is wrapped around the inner sheath 5 by clockwise unidirectional twisting, and another portion of aramid fibers is wrapped around the inner sheath 5 by counterclockwise unidirectional twisting, thus forming a non-metallic reinforcing layer 6.

[0072] The outer sheath 7 is tightly extruded onto the outside of the non-metallic reinforcing layer 6 using an extrusion process. To ensure that the aramid fiber and the inner GFRP sheath can withstand sufficient stress when the optical cable is suspended in the air, the outer sheath stripping force needs to be tested to verify whether the extrusion process can ensure that the outer sheath tightly covers the aramid fiber. Typically, the stripping force for a 30cm long outer sheath is at least 600N.

[0073] Example 2

[0074] A self-supporting all-dielectric overhead optical cable comprises a micro-bubble tube 1, a water-blocking material 2, an anti-sticking isolation layer 3, an inner sheath 5, a non-metallic reinforcing layer 6, and an outer sheath 7.

[0075] Water-blocking material 2 is made of water-blocking yarn, anti-sticking isolation layer 3 is made of water-blocking tape, and non-metallic reinforcing layer 6 is made of aramid fiber.

[0076] The bundle consists of 24 microtubes 1, each containing 12 optical fibers. The gaps between the optical fibers inside the microtubes are filled with fiber grease. The 24 microtubes 1 are unidirectionally twisted together to form a single bundle. Water-blocking material 2 fills the spaces between the microtubes.

[0077] The anti-adhesion isolation layer 3 longitudinally encloses the bundled microtubes 1 and water-blocking material 2. The circular cross-sectional area enclosed by the anti-adhesion isolation layer 3 is twice the sum of the cross-sectional areas of the microtubes 1 and the water-blocking material 2.

[0078] The inner sheath 5 covers the aforementioned water-blocking tape. The outer diameter D of the inner sheath 5 is 12mm, and 15≤K≤45, resulting in a calculated diameter of 565mm≤H≤1696mm. Four GFRP fibers (1.6mm in diameter) are embedded inside the inner sheath, arranged symmetrically in two groups. To ensure the GFRP fibers function effectively under stress, the minimum sheath thickness around the GFRP fibers is 0.3mm. A portion of aramid fibers is unidirectionally twisted clockwise and another portion is unidirectionally twisted counterclockwise, forming the non-metallic reinforcing layer 6. The outer sheath 7 is tightly extruded onto the outside of the non-metallic reinforcing layer 6 using an extrusion process.

[0079] Based on the above embodiment 2, the twist pitch H of the non-metallic reinforcing layer 6 is adjusted to form the five cases shown in Table 1 below:

[0080] Table 1

[0081] Method for measuring aramid excess length: Take a 5m length of optical cable, strip the outer sheath, and measure the aramid length, accurate to mm. The formula is: Aramid excess length (‰) = Aramid length (mm) / 5000 (mm) * 1000.

[0082] The tensile test was conducted according to Method E1 of GB / T 7424.21 "General Specification for Optical Cables Part 21: Basic Test Methods for Mechanical Properties of Optical Cables", and the strain value of the optical fiber under a tensile force of 3000N was measured.

[0083] From the five cases in Table 1 above, it can be seen that when the stranding pitch H of the non-metallic reinforcing layer 6 is limited to: H=D×π×K, 15≤K≤45, the aramid excess length and fiber strain effect are the best. However, for conditions below or above this, the above performance test results deteriorate.

[0084] It is evident that by limiting the twist pitch H of the non-metallic reinforcing layer 6, the force can be effectively transmitted.

[0085] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and 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. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0086] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0087] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A self-supporting all-dielectric overhead optical cable, characterized in that, It includes, from the inside out, a cable core, an inner sheath (5), a non-metallic reinforcing layer (6), and an outer sheath (7); The cable core comprises several microtube bundles (1) twisted together as one piece; The inner sheath (5) is embedded with a rigid non-metallic reinforcing member (4); The non-metallic reinforcing layer (6) is twisted around the outer periphery of the inner sheath (5); The outer sheath (7) covers the non-metallic reinforcing layer (6).

2. The all-dielectric self-supporting overhead optical cable as described in claim 1, characterized in that: The non-metallic reinforcing layer (6) is made of aramid or fiberglass yarn, which is twisted to the outer periphery of the inner sheath (5) in a unidirectional or bidirectional twisting manner.

3. The all-dielectric self-supporting overhead optical cable as described in claim 1, characterized in that: The outer sheath (7) is configured such that the stripping force required to strip the 30cm long outer sheath (7) longitudinally is not less than 600N.

4. The all-dielectric self-supporting overhead optical cable as described in claim 1, characterized in that: An anti-sticking isolation layer (3) is provided between the inner sheath (5) and the cable core, and the anti-sticking isolation layer (3) is located on the inner wall of the inner sheath (5).

5. The all-dielectric self-supporting overhead optical cable as described in claim 4, characterized in that: The material of the anti-stick isolation layer (3) includes one or more of aramid, fiberglass yarn, polyester tape and non-woven fabric.

6. The all-dielectric self-supporting overhead optical cable as described in claim 4, characterized in that: The cross-sectional area of ​​the cable core accounts for 40% to 70% of the cross-sectional area inside the anti-sticking isolation layer (3).

7. The all-dielectric self-supporting overhead optical cable as described in claim 1, characterized in that: The stranding pitch H of the non-metallic reinforcing layer (6) satisfies: H = D × π × K; D is the outer diameter of the inner sheath (5), K is the twisting coefficient, 15≤K≤45.

8. The all-dielectric self-supporting overhead optical cable as described in claim 1, characterized in that: The cable core also includes a water-blocking material (2), and the water-blocking material (2) is disposed between the micro-tubes (1).

9. The all-dielectric self-supporting overhead optical cable as described in claim 8, characterized in that: The water-blocking material (2) includes one or more of water-blocking yarn and water-blocking powder.

10. The all-dielectric self-supporting overhead optical cable as described in claim 1, characterized in that: The microtube (1) is made of one of thermoplastic polyester elastomer, thermoplastic elastomer, polyurethane and polyolefin. And / or, the optical fiber in the micro-tube (1) is provided with a water-blocking material (2), the water-blocking material (2) including one or more of water-blocking yarn, water-blocking powder and water-blocking fiber paste; And / or, the number of optical fibers in the micro-bundle tube (1) is 1 to 24; And / or, the number of micro-tube bundles (1) is 1 to 48, and multiple micro-tube bundles (1) are arranged in an orderly manner by SZ twisting or unidirectional twisting and loosely bundled by tie yarn; And / or, the inner sheath (5) is made of one of polyethylene or low-smoke halogen-free flame-retardant polyolefin; And / or, the rigid non-metallic reinforcing member (4) is made of either glass fiber reinforced plastic rod or aramid reinforced plastic rod; And / or, the diameter of the rigid non-metallic reinforcing member (4) is 0.5 to 2.5 mm; And / or, the number of the rigid non-metallic reinforcing members (4) is even, and they are symmetrically distributed on both sides of the inner sheath (5); And / or, the cross-sectional area of ​​the cable core accounts for 40% to 70% of the cross-sectional area inside the inner sheath (5).

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