A full-dry overhead optical cable and a method for manufacturing the same

Abstract

The application discloses a full-dry overhead optical cable, which comprises a cable core and an outer sheath for accommodating the cable core; a gap exists between the cable core and the outer sheath; the cable core comprises a structural middle core in the middle of the cable core and a plurality of sleeve units twisted around the structural middle core; foamed glue is filled between adjacent sleeve units and the structural middle core, and the foamed glue forms axially continuous convex ridges outside the structural middle core. The full-dry overhead optical cable provided by the application adopts the foamed glue to fix the sleeve and the structural middle core, provides the rigidity of the optical cable, reduces the influence of wind vibration on the sleeve unit, including vibration and sliding, and thus guarantees the stable performance, reliability and service life of the optical cable. The foamed glue is adopted to stabilize the cable core structure, and no binding yarn is needed, so that the production cost is reduced, and the risk of the sleeve being damaged and the cable core being broken caused by the binding yarn is avoided.

Description

Technical Field

[0001] This invention belongs to the field of optical communication, and more specifically, relates to a fully dry overhead optical cable and its preparation method. Background Technology

[0002] Aerial fiber optic cables, typically including figure-eight type, ADSS type, and lightly armored stranded fiber optic cables, have been widely used in backbone networks, access networks, and FTTH applications due to their advantages such as convenient construction and maintenance and lack of route restrictions. However, aerial fiber optic cable laying is limited by pole and tower resources and load-bearing safety, restricting the cable diameter and weight from being too large.

[0003] The use of a fully dry structure eliminates the need for fiber optic paste and cable grease, significantly reducing the weight of the optical cable and offering advantages such as environmental friendliness and ease of installation. However, aerial optical cables with a fully dry structure are significantly affected by wind vibration due to the lack of fiber optic paste and cable grease cushioning, leading to a reduction in cable lifespan and communication reliability. Summary of the Invention

[0004] To address the aforementioned deficiencies or improvement needs of existing technologies, this invention provides a fully dry overhead optical cable and its preparation method. The purpose is to form convex ridges on the outer side of the core of the structure using foam adhesive, thereby improving the rigidity of the optical cable and reducing the impact of wind vibration on the optical fiber, ensuring the reliability and service life of the optical cable. This solves the technical problem that the rigidity of fully dry overhead optical cables is insufficient to buffer the impact of wind vibration, resulting in reduced service life and lower communication reliability.

[0005] To achieve the above objectives, according to one aspect of the present invention, a fully dry overhead optical cable is provided, comprising: a cable core and an outer sheath for housing the cable core; a gap exists between the cable core and the outer sheath;

[0006] The cable core includes a structural core located in the middle of the cable core, and

[0007] Multiple sleeve units are stranded around the core of the structure;

[0008] Foam is used to fill the space between adjacent sleeve units and the core of the structure, and the foam forms axially continuous convex ridges on the outer side of the core of the structure.

[0009] Preferably, the fully dry overhead optical cable has a circular cross-section in its core structure, which is a lightweight filler rope, a reinforcing member, or a reserved air blowing pipe.

[0010] Preferably, in the fully dry overhead optical cable, the cross-section of each of the sheath units is circular, the diameter of the plurality of sheath units is the same, and the ratio of the diameter between the core and the sheath unit is between 0.7 and 3.5.

[0011] Preferably, the foaming degree of the foaming adhesive in the all-dry overhead optical cable is between 20 and 25 times.

[0012] Preferably, the all-dry overhead optical cable has a water-blocking tape wrapped longitudinally around the outside of the cable core, and water-blocking powder is adhered to the outer surface of the water-blocking tape; the sleeve unit is an all-dry sleeve unit, which has water-blocking yarn or water-blocking powder.

[0013] Preferably, the fully dry overhead optical cable is a figure-eight type optical cable, and its outer sheath has a reinforcing member that is parallel to the cable core and extends axially.

[0014] According to another aspect of the present invention, a method for preparing the aforementioned all-dry overhead optical cable is provided, comprising the following steps:

[0015] A certain amount of foam adhesive is applied to the outside of the core of the structure, and multiple sleeve units are arranged circumferentially on the outside of the core of the structure coated with foam adhesive.

[0016] The foaming adhesive is foamed and fills the gap between adjacent sleeve units and the core of the structure, forming an axially continuous convex ridge on the outer side of the core of the structure.

[0017] Preferably, in the method for preparing the all-dry overhead optical cable, a water-blocking strip is longitudinally wrapped around the outside of multiple sleeve units arranged in a circle to form a cable core, and water-blocking powder is adhered to the outer surface of the water-blocking strip.

[0018] Preferably, the method for preparing the all-dry overhead optical cable includes the following steps:

[0019] Sheath material is extruded from the outside of the cable core to form the outer sheath.

[0020] Preferably, the method for preparing the all-dry overhead optical cable involves extruding figure-eight shaped sheath material onto the outside of the cable core and the reinforcing member parallel to the cable core to form an outer sheath.

[0021] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects:

[0022] The all-dry overhead optical cable provided by this invention uses a foam-fixed sheath and structural core, which provides rigidity to the optical cable while reducing the impact of wind vibration and galloping on the sheath unit, including vibration and slippage, thereby ensuring the stability, reliability, and service life of the optical cable. Using foam to stabilize the cable core structure eliminates the need for yarn binding, reducing production costs and avoiding the risks of defective products such as punctured sheaths and broken cable cores caused by yarn binding.

[0023] Meanwhile, the use of an oil-free, fully dry structure greatly reduces the weight of the optical cable, which is conducive to increasing the number of optical fiber cores in the overhead optical cable while ensuring the safety of the tower load.

[0024] In the preferred embodiment, the sheath unit in the cable core is bonded to the core of the structure with foam to form an integral rigidity, which effectively improves the rigidity. The reinforcing core can be replaced with a lower-cost filler rope, which helps to reduce costs and lighten the weight of the optical cable. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the cross-sectional structure of the all-dry overhead optical cable provided in Embodiment 1 of the present invention;

[0026] Figure 2 This is an enlarged structural diagram of the all-dry overhead optical cable core provided in Embodiment 1 of the present invention;

[0027] Figure 3 This is a schematic diagram of the cross-sectional structure of the all-dry overhead optical cable provided in Embodiment 2 of the present invention;

[0028] Figure 4 This is a schematic diagram of the cross-sectional structure of the all-dry overhead optical cable provided in Embodiment 3 of the present invention.

[0029] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1 is optical fiber, 2 is water-blocking yarn, 3 is sleeve unit, 4 is foam, 5 is structural core, 6 is water-blocking tape, 7 is outer sheath, and 8 is reinforcement. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0031] The all-dry overhead optical cable provided by this invention, such as Figure 1 As shown, it includes: a cable core and an outer sheath for housing the cable core; a gap exists between the cable core and the outer sheath;

[0032] The cable core includes a structural core located in the middle of the cable core, and a plurality of sleeve units twisted around the structural core;

[0033] The core of the structure has a circular cross-section and is a lightweight filler rope, reinforcing member, or reserved air blowing pipe.

[0034] The cross-section of each sleeve unit is circular, and the multiple sleeve units have the same diameter. The diameter ratio between the core of the structure and the sleeve unit is between 0.7 and 3.5. The sleeve unit is a fully dry sleeve unit, equipped with water-blocking yarn or water-blocking powder. Circular sleeve units of the same diameter are used, and there is a triangular-like gap between adjacent sleeve units and the core of the structure. Figure 2 As shown. Considering the expansion process of the foam, a sufficiently large space is required between adjacent sleeve units and the structural core. The ratio of the diameter of the structural core to the diameter of the sleeve unit should be greater than or equal to 0.7. An excessively large diameter of the structural core will result in an excessively large cable diameter and a decrease in fiber density. The reserved air-blowing duct, serving as the structural core, generally has a relatively large size, with its diameter typically less than or equal to 3.5 times the diameter of the sleeve unit.

[0035] Foam is used to fill the space between adjacent sleeve units and the core of the structure, forming axially continuous raised ridges on the outer side of the core. The foaming degree of the foam is between 20 and 25 times. The raised ridges formed by the foam have a shock-resistant function; however, the foaming process may cause instability in the cable core, and the manufacturing process is not easy to control. Therefore, using foam with a lower foaming degree is beneficial to process stability, improving product consistency, and also to improving cable rigidity.

[0036] Aerial optical cables typically exhibit sag, bending downwards to adapt to varying temperatures. However, they are significantly affected by wind vibrations caused by natural wind or airflow. Foam is used to fill the gaps between adjacent sheath units and the core structure, thus fixing them in place, preventing slippage, and the protruding prismatic structure effectively improves the core's rigidity. When subjected to high-velocity airflow, the foam strengthens the core's integrity, increases rigidity, and reduces vibration amplitude. Unlike other adhesives, foam acts as a shock absorber, providing cushioning for the sheath units and internal optical fibers when the cable is subjected to wind vibrations, effectively ensuring the cable's reliability and lifespan.

[0037] In addition, since there is a gap between the cable core and the outer sheath, there is a certain buffer space between the sheath and the cable core, which reduces the impact of wind vibration.

[0038] Especially when the core of the structure is a lightweight filler rope and an air-blown pipe, the foam can compensate to some extent for the deterioration of tensile strength caused by the lack of a central reinforcing member.

[0039] Simultaneously, the adhesive effect of the foam helps stabilize the cable core, allowing the sheath to be extruded directly without yarn binding. A preferred embodiment involves longitudinally wrapping a water-blocking tape around the outside of the cable core, with water-blocking powder adhered to its outer surface. This helps stabilize the circumferentially arranged sleeve units, typically a stranded cable core.

[0040] The method for preparing a fully dry overhead optical cable provided by the present invention includes the following steps:

[0041] A quantitative amount of expanding foam is applied to the outside of the core structure. Multiple sleeve units are arranged circumferentially around the outside of the core structure coated with expanding foam. The expanding foam foams and fills the gaps between adjacent sleeve units and the core structure, forming axially continuous convex ridges on the outside of the core structure. A water-blocking tape is longitudinally wrapped around the outside of the multiple sleeve units arranged circumferentially to form the cable core. Water-blocking powder is adhered to the outer surface of the water-blocking tape.

[0042] Sheath material is extruded from the outside of the cable core to form the outer sheath.

[0043] The following is an example:

[0044] Example 1

[0045] The cross-sectional structure diagram of the all-dry overhead optical cable provided in this embodiment is shown below. Figure 1 As shown, the cable is a figure-eight type, comprising: a cable core and an outer sheath 7 for housing the cable core; there is a gap between the cable core and the outer sheath 7.

[0046] The cable core, such as Figure 2 As shown, it includes a structural core 5 located in the middle of the cable core, and nine sleeve units 3 twisted around the structural core 5; this embodiment adopts a 6-core dry sleeve unit, which has 6 colored optical fibers 1 and a water-blocking yarn 2.

[0047] The core 5 in the structure has a circular cross-section and is a lightweight filler rope.

[0048] All sleeve units 3 have circular cross-sections and the same diameter. The diameter ratio between the structural core 5 and the sleeve unit 3 is 1.95. A triangular gap exists between adjacent sleeve units 3 and the structural core 5. Expanding foam 4 fills the gap between adjacent sleeve units 3 and the structural core 5, forming axially continuous convex ridges on the outer side of the structural core. The expansion ratio of the expanding foam 4 is 22 times.

[0049] A water-blocking tape 6 is longitudinally wrapped around the outside of the cable core, and water-blocking powder is adhered to the outer surface of the water-blocking tape. This helps stabilize the circumferentially arranged sleeve units, which are typically stranded cable cores.

[0050] Its outer sheath 7 has a reinforcing member 8 that is parallel to and extends axially with the cable core, and the reinforcing member is stranded steel wire.

[0051] The method for preparing a fully dry overhead optical cable provided in this embodiment includes the following steps:

[0052] A quantitative amount of expanding foam 4 is applied to the outer side of the core 5 of the structure. Nine sleeve units 3 are arranged circumferentially on the outer side of the core 5 coated with expanding foam 4. The expanding foam 4 foams and fills the gap between adjacent sleeve units and the core 5, forming an axially continuous convex ridge on the outer side of the core 5. A water-blocking tape 6 is longitudinally wrapped around the outer side of the multiple sleeve units 3 arranged circumferentially to form a cable core. Water-blocking powder is adhered to the outer surface of the water-blocking tape.

[0053] The outer sheath 7 is formed by extruding a figure-eight shaped sheath material on the outside of the cable core and setting reinforcements, then cooling and shaping.

[0054] The fully dry overhead optical cable provided in this embodiment does not require yarn binding to form the cable core, and its rigidity test result is 8.4 N*m. 2 Similar to the figure-eight optical cable with the same structure but without foam filling and formed by binding yarn (rigidity 7.5 N*m) 2 Compared to the previous version, rigidity has increased by 12%.

[0055] Example 2

[0056] The cross-sectional structure diagram of the all-dry overhead optical cable provided in this embodiment is shown below. Figure 3 As shown, the cable is a figure-eight type, comprising: a cable core and an outer sheath 7 for housing the cable core; there is a gap between the cable core and the outer sheath 7.

[0057] The cable core includes a structural core 5 located in the middle of the cable core, and 12 sleeve units 3 twisted around the structural core 5; this embodiment adopts a 6-core dry sleeve unit, which has 6 colored optical fibers 1 and a water-blocking yarn 2.

[0058] The core 5 of the structure has a circular cross-section, which serves as a pre-reserved air blowing pipe.

[0059] All sleeve units 3 have circular cross-sections and the same diameter. The diameter ratio between the structural core 5 and the sleeve unit 3 is 3.1. A triangular gap exists between adjacent sleeve units 3 and the structural core 5. Expanding foam 4 fills the gap between adjacent sleeve units 3 and the structural core 5, forming axially continuous convex ridges on the outer side of the structural core. The expansion ratio of the expanding foam 4 is 22 times.

[0060] A water-blocking tape 6 is longitudinally wrapped around the outside of the cable core, and water-blocking powder is adhered to the outer surface of the water-blocking tape. This helps stabilize the circumferentially arranged sleeve units, which are typically stranded cable cores.

[0061] Its outer sheath 7 has a reinforcing member 8 that is parallel to and extends axially with the cable core. The reinforcing member is a stranded steel wire. The outer sheath of the cable core has an FRP reinforcing member that is disposed opposite to it.

[0062] The method for preparing a fully dry overhead optical cable provided in this embodiment includes the following steps:

[0063] A quantitative amount of expanding foam 4 is applied to the outer side of the core 5 of the structure. Nine sleeve units 3 are arranged circumferentially on the outer side of the core 5 coated with expanding foam 4. The expanding foam 4 foams and fills the gap between adjacent sleeve units and the core 5, forming an axially continuous convex ridge on the outer side of the core 5. A water-blocking tape 6 is longitudinally wrapped around the outer side of the multiple sleeve units 3 arranged circumferentially to form a cable core. Water-blocking powder is adhered to the outer surface of the water-blocking tape.

[0064] The outer sheath 7 is formed by extruding a figure-eight shaped sheath material on the outside of the cable core and setting reinforcements, then cooling and shaping.

[0065] The fully dry overhead optical cable provided in this embodiment does not require yarn binding to form the cable core, and its rigidity test result is 8.1 N*m. 2 Similar to the figure-eight optical cable with the same structure but without foam filling and constructed using yarn binding (rigidity 7.2 N*m), this cable is a figure-eight shaped cable. 2 Compared to the previous version, rigidity has increased by 12.5%.

[0066] Example 3

[0067] The cross-sectional structure diagram of the all-dry overhead optical cable provided in this embodiment is shown below. Figure 4 As shown, an ADSS optical cable includes: a cable core and an outer sheath 7 for housing the cable core; a gap exists between the cable core and the outer sheath 7.

[0068] The cable core includes a structural core 5 located in the middle of the cable core, and nine sleeve units 3 twisted around the structural core 5; this embodiment adopts a 6-core dry sleeve unit, which has 6 colored optical fibers 1 and a water-blocking yarn 2.

[0069] The core 5 in the structure has a circular cross-section and serves as an FRP central reinforcement.

[0070] All sleeve units 3 have circular cross-sections and the same diameter. The diameter ratio between the structural core 5 and the sleeve unit 3 is 1.95. A triangular gap exists between adjacent sleeve units 3 and the structural core 5. Expanding foam 4 fills the gap between adjacent sleeve units 3 and the structural core 5, forming axially continuous convex ridges on the outer side of the structural core. The expansion ratio of the expanding foam 4 is 22 times.

[0071] A water-blocking tape 6 is longitudinally wrapped around the outside of the cable core, and water-blocking powder is adhered to the outer surface of the water-blocking tape. This helps stabilize the circumferentially arranged sleeve units, which are typically stranded cable cores.

[0072] Its outer sheath 7 has a reinforcing member 8 that is parallel to and extends axially with the cable core. The reinforcing member is a stranded steel wire. The outer sheath of the cable core has an FRP reinforcing member that is disposed opposite to it.

[0073] The method for preparing a fully dry overhead optical cable provided in this embodiment includes the following steps:

[0074] A quantitative amount of expanding foam 4 is applied to the outside of the core 5 of the structure. Nine sleeve units 3 are arranged circumferentially around the outside of the core 5 coated with expanding foam 4. The expanding foam 4 foams and fills the gaps between adjacent sleeve units and the core structure, forming axially continuous convex ridges on the outside of the core structure. A water-blocking tape 6 is longitudinally wrapped around the outside of the multiple sleeve units 3 arranged circumferentially to form a cable core. Water-blocking powder is adhered to the outer surface of the water-blocking tape.

[0075] Sheath material is extruded from the outside of the cable core, cooled and shaped to form the outer sheath 7.

[0076] The fully dry overhead optical cable provided in this embodiment does not require yarn binding to form the cable core, and its rigidity test result is 7.4 N*m. 2 Compared to ADSS optical cables with the same structure but without foam filling and constructed using yarn binding (rigidity test result: 6.3 N*m),... 2 Compared to the previous version, rigidity increased by 17.4%.

[0077] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A fully dry overhead optical cable, characterized in that, include: Cable core and outer sheath housing the cable core; There is a gap between the cable core and the outer sheath; The cable core includes a structural core located in the middle of the cable core, and Multiple sleeve units are stranded around the core of the structure; The core of the structure has a circular cross-section; Foam is used to fill the space between adjacent sleeve units and the core of the structure, and the foam forms axially continuous convex ridges on the outer side of the core of the structure; the sleeve units in the cable core are bonded together with the core of the structure by the foam.

2. The all-dry overhead optical cable as described in claim 1, characterized in that, The core of the structure is a lightweight filler rope, a reinforcing member, or a pre-installed air blowing pipe.

3. The all-dry overhead optical cable as described in claim 1, characterized in that, The cross-section of each sleeve unit is circular, and the diameters of the multiple sleeve units are the same. The ratio of the diameter of the core in the structure to the diameter of each sleeve unit is between 0.7 and 3.

5.

4. The all-dry overhead optical cable as described in claim 1, characterized in that, The expansion degree of the foam is between 20 and 25 times.

5. The all-dry overhead optical cable as described in claim 1, characterized in that, The cable core is longitudinally wrapped with a water-blocking tape, and the outer surface of the water-blocking tape is coated with water-blocking powder; the sleeve unit is a fully dry sleeve unit, which has water-blocking yarn or water-blocking powder.

6. The all-dry overhead optical cable as described in claim 1, characterized in that, The optical cable is a figure-eight type, and its outer sheath has a reinforcing member that is parallel to the cable core and extends axially.

7. A method for preparing a fully dry overhead optical cable as described in any one of claims 1 to 6, characterized in that, Includes the following steps: A certain amount of foam adhesive is applied to the outside of the core of the structure, and multiple sleeve units are arranged circumferentially on the outside of the core of the structure coated with foam adhesive. The foaming adhesive is foamed and fills the gap between adjacent sleeve units and the core of the structure, forming an axially continuous convex ridge on the outer side of the core of the structure.

8. The method for preparing a fully dry overhead optical cable as described in claim 7, characterized in that, A cable core is formed by longitudinally wrapping water-blocking tape around the outer side of multiple sleeve units arranged in a circle, and water-blocking powder is adhered to the outer surface of the water-blocking tape.

9. The method for preparing a fully dry overhead optical cable as described in claim 7, characterized in that, Includes the following steps: Sheath material is extruded from the outside of the cable core to form the outer sheath.

10. The method for preparing a fully dry overhead optical cable as described in claim 7, characterized in that, The outer sheath is formed by extruding figure-eight shaped sheath material on the outside of the cable core and the reinforcing member parallel to the cable core.

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