Full-dry overhead laying optical cable and preparation method thereof

Abstract

The invention discloses a full-dry type overhead laying 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 located in the middle of the cable core and a plurality of sleeve units stranded around the structural middle core; polystyrene foam is filled between the adjacent sleeve units and the structural middle core, and axially continuous ribs on the outer side of the structural middle core are formed by the polystyrene foam. According to the full-dry aerial optical cable provided by the invention, the sleeve and the structural middle core which are fixed by polystyrene foam are adopted, so that the influence of wind vibration galloping on the sleeve unit, including vibration and slippage, is reduced while the rigidity of the optical cable is provided, and thus the performance stability, reliability and service life of the optical cable are ensured. And the cable core structure is stabilized by adopting the polystyrene foam, and yarn binding is not needed, so that the production cost is reduced, and defective product risks such as the sleeve is punctured and the cable core is broken due to the adoption of the yarn binding are also avoided.

Description

Technical Field

[0001] The present invention belongs to the field of optical communication, and more specifically, relates to a fully dry overhead optical cable and a preparation method thereof. Background Art

[0002] Aerial optical cables, generally including figure-8 optical cables, ADSS optical cables, and lightly armored layer-stranded optical cables, have been widely used in backbone networks, access networks, and FTTH applications due to their advantages such as convenient construction and maintenance and no restrictions on routing. However, due to the limitations of pole tower resources and load-bearing safety, the diameter and weight of the optical cables cannot be too large.

[0003] The full-dry structure eliminates the need for fiber grease and cable grease, which can significantly reduce the weight of the optical cable and is environmentally friendly and easy to install. However, due to the lack of fiber grease and cable grease buffering, the full-dry structure overhead laying of optical cables is significantly affected by wind vibration, resulting in a reduced service life of the optical cable and reduced communication reliability. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a fully dry overhead optical cable and a preparation method thereof, the purpose of which is to form ridges on the outer side of the core of the structure by means of foam glue, so as to improve the rigidity of the optical cable and reduce the influence of wind vibration on the optical fiber, thereby ensuring the reliability and service life of the optical cable, thereby solving the technical problem that the rigidity of the fully dry structure overhead optical cable is not enough to buffer the influence of wind vibration, resulting in reduced service life of the optical cable and low communication reliability.

[0005] To achieve the above object, according to one aspect of the present invention, a fully dry type aerial optical cable is provided, comprising: a cable core and an outer sheath accommodating the cable core; a gap is provided between the cable core and the outer sheath;

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

[0007] a plurality of sleeve units twisted around a core in the structure;

[0008] The space between adjacent sleeve units and the core of the structure is filled with foamed rubber, and the foamed rubber forms axially continuous convex ridges on the outer side of the core of the structure.

[0009] Preferably, the structural core of the fully dry overhead optical cable has a circular cross-section and is a lightweight filling rope, a reinforcement member or a reserved air blowing duct.

[0010] Preferably, in the fully dry aerial optical cable, the cross-sections of the casing units are all circular, the diameters of the multiple casing units are the same, and the ratio of the diameters of the core in the structure to the casing units is between 0.7 and 3.5.

[0011] Preferably, the foaming degree of the foamed glue in the fully dry overhead optical cable is between 20 and 25 times.

[0012] Preferably, the outer side of the cable core of the fully dry overhead optical cable is longitudinally wrapped with a water-blocking tape, and the outer surface of the water-blocking tape is adhered with water-blocking powder; the casing unit is a fully dry casing unit, having water-blocking yarn or water-blocking powder.

[0013] Preferably, the fully dry type aerial optical cable is an 8-shaped optical cable, and its outer sheath has a reinforcement member which is parallel to the cable core and extends axially.

[0014] According to another aspect of the present invention, there is provided a method for preparing the fully dry type aerial optical cable, comprising the following steps:

[0015] A foam glue is quantitatively coated on the outer side of the structure core, and a plurality of sleeve units are arranged circumferentially on the outer side of the structure core coated with the foam glue;

[0016] The foamable adhesive foams and fills the gap between the adjacent sleeve units and the core of the structure, forming axially continuous convex ridges on the outer side of the core of the structure.

[0017] Preferably, in the method for preparing the fully dry aerial optical cable, a plurality of casing units are arranged circumferentially and longitudinally wrapped with water-blocking tape on the outside to form a cable core, and water-blocking powder is adhered to the outer surface of the water-blocking tape.

[0018] Preferably, the method for preparing the fully dry type aerial optical cable comprises the following steps:

[0019] The sheath material is extruded on the outside of the cable core to form an outer sheath.

[0020] Preferably, the method for preparing the fully dry type aerial optical cable comprises extruding an 8-shaped sheath material on the outside of the cable core and the reinforcement member parallel to the cable core to form an outer sheath.

[0021] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0022] The fully dry overhead optical cable provided by the present invention adopts a casing and a structural core fixed by foam glue, which provides the rigidity of the optical cable while reducing the impact of wind vibration on the casing unit, including vibration and slippage, thereby ensuring the stable performance, reliability and service life of the optical cable. The cable core structure is stabilized by foam glue, and no yarn is required, which not only reduces the production cost, but also avoids the risk of inferior products such as casing being punctured and cable core being broken due to the use of yarn tying.

[0023] At the same time, the full dry structure without oil filling 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 solution, the sleeve unit in the cable core and the structural core are bonded together by foam adhesive to form an integral whole, and the rigidity is effectively improved. The reinforcing core can be replaced by a lower-cost filling rope, which is beneficial to reducing the cost and weight of the optical cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of the cross-sectional structure of a fully dry aerial optical cable provided in Example 1 of the present invention;

[0026] Figure 2 It is a schematic diagram of the enlarged structure of the core of the fully dry overhead optical cable provided in Example 1 of the present invention;

[0027] Figure 3 is a schematic diagram of the cross-sectional structure of a fully dry aerial optical cable provided in Example 2 of the present invention;

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

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

[0030] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] The fully dry type aerial optical cable provided by the present invention is as follows: Figure 1 As shown, it comprises: a cable core and an outer sheath for accommodating the cable core; there is a gap between the cable core and the outer sheath;

[0032] The cable core comprises a structural core 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 filling rope, a reinforcement member or a reserved air blowing pipeline.

[0034] The cross-section of the sleeve units is circular, the diameters of the multiple sleeve units are the same, the diameter ratio between the core of the structure and the sleeve units is between 0.7 and 3.5, and the sleeve units are fully dry sleeve units with water-blocking yarn or water-blocking powder. Circular sleeve units with the same diameter are used, and there is a triangular gap between adjacent sleeve units and the core of the structure, such as Figure 2 As shown. Considering the expansion process of the foaming volume of the foam glue, there needs to be a large enough space between the adjacent casing units and the structural core, and the ratio of the diameter of the structural core to the casing unit is greater than or equal to 0.7. If the diameter of the structural core is too large, the cable diameter will be too large and the optical fiber density will decrease. The reserved air blowing duct as the structural core generally has a larger size, and its diameter is generally less than or equal to 3.5 times the diameter of the casing unit.

[0035] The space between adjacent casing units and the core of the structure is filled with foamed glue, and the foamed glue forms axially continuous ridges on the outer side of the core of the structure. The foaming degree of the foamed glue is between 20 and 25 times. The ridges formed by the foamed glue have an anti-seismic function, but the foaming process may cause instability of the cable core, and the manufacturing process is difficult to control. Therefore, the use of foamed glue with a lower foaming degree is conducive to process stability, improving product consistency, and at the same time helping to improve the rigidity of the cable body.

[0036] Aerial optical cables generally have sag, and the cables bend downward to adapt to working at different temperatures. However, overhead optical cables are affected by natural wind or air blowing, and are significantly affected by wind vibration. Foam glue is used to fill the gaps between adjacent casing units and the structural core, thereby fixing the casing units and the structural core, preventing slippage between the casing units, and the protruding prismatic structure effectively improves the rigidity of the cable core. When the cable body or cable core is acted on by high-velocity air, the integrity of the cable core is enhanced due to the presence of foam glue, the rigidity is increased, and the vibration amplitude is reduced. At the same time, unlike other types of adhesives, foam glue can play a shock-absorbing role. When the cable body is vibrated by wind, it provides a buffer for the casing unit and the optical fiber inside it, thereby effectively ensuring the reliability and service life of the optical cable.

[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 weakens the influence of wind vibration.

[0038] Especially when the core of the structure is a lightweight filling rope and an air-blown duct, the foamed adhesive can compensate to a certain extent for the deterioration of the tensile properties caused by the lack of a central reinforcement.

[0039] At the same time, the adhesive effect of the foam helps to stabilize the cable core, and the sheath can be directly extruded without yarn binding. The preferred solution is to wrap a water-blocking tape longitudinally on the outside of the cable core, and the outer surface of the water-blocking tape is adhered with water-blocking powder. This helps to stabilize the circumferentially arranged casing units, which are typically layer-twisted cable cores.

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

[0041] A certain amount of foam glue is applied to the outer side of the structural core, and a plurality of sleeve units are arranged circumferentially on the outer side of the structural core coated with foam glue; the foam glue is allowed to foam and fill the gap between the adjacent sleeve units and the structural core, forming an axially continuous convex ridge on the outer side of the structural core. A plurality of sleeve units are arranged circumferentially and longitudinally wrapped with water blocking tape to form a cable core, and the outer surface of the water blocking tape is adhered with water blocking powder.

[0042] The sheath material is extruded on the outside of the cable core to form an outer sheath.

[0043] The following are examples:

[0044] Example 1

[0045] The fully dry type aerial optical cable provided in this embodiment has a cross-sectional structure schematic diagram as shown in FIG. Figure 1 As shown, it is an 8-shaped optical cable, comprising: a cable core and an outer sheath 7 for accommodating 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 in the middle of the cable core, and 9 sleeve units 3 twisted around the structural core 5; this embodiment adopts a 6-core full-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 light filling rope.

[0048] The cross-sections of the sleeve units 3 are all circular, and the diameters of the sleeve units 3 are the same. The diameter ratio between the structural core 5 and the sleeve units 3 is 1.95. There is a triangular gap between adjacent sleeve units 3 and the structural core 5. The gap between adjacent sleeve units 3 and the structural core 5 is filled with foam glue 4, and the foam glue 4 forms a continuous convex ridge on the outer side of the structural core. The foaming degree of the foam glue 4 is 22 times.

[0049] The outer side of the cable core is longitudinally wrapped with a water blocking tape 6, and the outer surface of the water blocking tape is adhered with water blocking powder, which helps to stabilize the circumferentially arranged casing units, which are typically layer-twisted cable cores.

[0050] The outer sheath 7 has a strength member 8 which is parallel to the cable core and extends axially, and the strength member is a twisted steel wire.

[0051] The method for preparing the fully dry type aerial optical cable provided in this embodiment comprises the following steps:

[0052] A foam glue 4 is quantitatively coated on the outer side 1 of the structural core, and 9 sleeve units 3 are arranged circumferentially on the outer side of the structural core 5 coated with the foam glue 4; the foam glue 4 is foamed and fills the gap between the adjacent sleeve units and the structural core to form an axially continuous convex ridge on the outer side of the structural core. A plurality of sleeve units 3 are arranged circumferentially and longitudinally wrapped with a water blocking tape 6 on the outer side to form a cable core, and the outer surface of the water blocking tape is adhered with water blocking powder.

[0053] An 8-shaped sheath material is extruded on the outside of the cable core and a reinforcement piece is arranged, and the sheath material is cooled and shaped to form an outer sheath 7 .

[0054] The fully dry type aerial optical cable provided in this embodiment does not need to be tied to form a cable core, and the rigidity test result is 8.4N*m 2 , with the same structure without foam filling and using yarn-bound 8-shaped optical cable (rigidity 7.5N*m 2 ) compared to the previous model, the rigidity is increased by 12%.

[0055] Example 2

[0056] The fully dry type aerial optical cable provided in this embodiment has a cross-sectional structure schematic diagram as shown in FIG. Figure 3 As shown, it is an 8-shaped optical cable, comprising: a cable core and an outer sheath 7 for accommodating 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 in the middle of the cable core, and 12 sleeve units 3 twisted around the structural core 5; this embodiment adopts a 6-core full-dry sleeve unit, which has 6 colored optical fibers 1 and a water-blocking yarn 2.

[0058] The core 5 in the structure has a circular cross section and is a reserved air blowing pipeline.

[0059] The cross-sections of the sleeve units 3 are all circular, the diameters of the sleeve units 3 are the same, and the diameter ratio between the structural core 5 and the sleeve units 3 is 3.1. There is a triangular gap between adjacent sleeve units 3 and the structural core 5, and the gap between adjacent sleeve units 3 and the structural core 5 is filled with foam glue 4, which forms axially continuous convex ridges on the outer side of the structural core. The foaming degree of the foam glue 4 is 22 times.

[0060] The outer side of the cable core is longitudinally wrapped with a water blocking tape 6, and the outer surface of the water blocking tape is adhered with water blocking powder, which helps to stabilize the circumferentially arranged casing units, which are typically layer-twisted cable cores.

[0061] The outer sheath 7 has a reinforcing member 8 which is parallel to the cable core and extends axially, and the reinforcing member is a twisted steel wire; the outer sheath of the cable core has an FRP reinforcing member which is arranged oppositely.

[0062] The method for preparing the fully dry type aerial optical cable provided in this embodiment comprises the following steps:

[0063] A foam glue 4 is quantitatively coated on the outer side 1 of the structural core, and 9 sleeve units 3 are arranged circumferentially on the outer side of the structural core 5 coated with the foam glue 4; the foam glue 4 is foamed and fills the gap between the adjacent sleeve units and the structural core to form an axially continuous convex ridge on the outer side of the structural core. A plurality of sleeve units 3 are arranged circumferentially and longitudinally wrapped with a water blocking tape 6 on the outer side to form a cable core, and the outer surface of the water blocking tape is adhered with water blocking powder.

[0064] An 8-shaped sheath material is extruded on the outside of the cable core and a reinforcement piece is arranged, and the sheath material is cooled and shaped to form an outer sheath 7 .

[0065] The fully dry type aerial optical cable provided in this embodiment does not need to be tied to form a cable core, and the rigidity test result is 8.1N*m 2 , with the same structure without foam filling and using yarn-bound 8-shaped optical cable (rigidity 7.2N*m 2 ) compared to the previous model, the rigidity is increased by 12.5%.

[0066] Example 3

[0067] The fully dry type aerial optical cable provided in this embodiment has a cross-sectional structure schematic diagram as shown in FIG. Figure 4 As shown, it is an ADSS optical cable, comprising: a cable core and an outer sheath 7 for accommodating the cable core; there is a gap between the cable core and the outer sheath 7;

[0068] The cable core includes a structural core 5 in the middle of the cable core, and 9 sleeve units 3 twisted around the structural core 5; this embodiment adopts a 6-core full-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 is a FRP central reinforcement.

[0070] The cross-sections of the sleeve units 3 are all circular, and the diameters of the sleeve units 3 are the same. The diameter ratio between the structural core 5 and the sleeve units 3 is 1.95. There is a triangular gap between adjacent sleeve units 3 and the structural core 5. The gap between adjacent sleeve units 3 and the structural core 5 is filled with foam glue 4, and the foam glue 4 forms a continuous convex ridge on the outer side of the structural core. The foaming degree of the foam glue 4 is 22 times.

[0071] The outer side of the cable core is longitudinally wrapped with a water blocking tape 6, and the outer surface of the water blocking tape is adhered with water blocking powder, which helps to stabilize the circumferentially arranged casing units, which are typically layer-twisted cable cores.

[0072] The outer sheath 7 has a reinforcing member 8 which is parallel to the cable core and extends axially, and the reinforcing member is a twisted steel wire; the outer sheath of the cable core has an FRP reinforcing member which is arranged oppositely.

[0073] The method for preparing the fully dry type aerial optical cable provided in this embodiment comprises the following steps:

[0074] A foam glue 4 is quantitatively coated on the outside of the structural core 5, and 9 sleeve units 3 are arranged circumferentially on the outside of the structural core 5 coated with the foam glue 4; the foam glue 4 is foamed and fills the gap between the adjacent sleeve units and the structural core to form an axially continuous convex ridge on the outside of the structural core. A plurality of sleeve units 3 are arranged circumferentially and longitudinally wrapped with a water blocking tape 6 to form a cable core, and the outer surface of the water blocking tape is adhered with water blocking powder.

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

[0076] The fully dry type aerial optical cable provided in this embodiment does not need to be tied to form a cable core, and the rigidity test result is 7.4N*m 2 , compared with the ADSS optical cable with the same structure and no foam filling and yarn-bound cable (rigidity test result is 6.3N*m 2 ) compared to the previous model, the rigidity is increased by 17.4%.

[0077] It will be easily understood by those skilled in the art that the above description is only 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 in the protection scope of the present invention.

Claims

1. A fully dry overhead optical cable, characterized in that: include: A cable core and an outer sheath accommodating the cable core; There is a gap between the cable core and the outer sheath; The cable core includes a structural core in the middle of the cable core, and a plurality of sleeve units twisted around a core in the structure; The space between adjacent sleeve units and the core of the structure is filled with foamed rubber, and the foamed rubber forms axially continuous convex ridges on the outer side of the core of the structure.

2. The fully dry overhead optical cable according to claim 1, characterized in that: The core of the structure has a circular cross section and is a lightweight filling rope, a reinforcement member or a reserved air blowing pipeline.

3. The fully dry overhead optical cable according to claim 1, characterized in that: The cross sections of the sleeve units are all circular, the diameters of the multiple sleeve units are the same, and the ratio of the diameters of the core in the structure to the sleeve units is between 0.7 and 3.

5.

4. The fully dry type aerial optical cable according to claim 1, characterized in that: The foaming degree of the foaming glue is between 20 and 25 times.

5. The fully dry type aerial optical cable according to claim 1, characterized in that: The outer side of the cable core is longitudinally wrapped with a water-blocking tape, and the outer surface of the water-blocking tape is adhered with water-blocking powder; the casing unit is a full-dry casing unit, which has water-blocking yarn or water-blocking powder.

6. The fully dry overhead optical cable according to claim 1, characterized in that: The optical cable is an 8-shaped optical cable, and its outer sheath has a reinforcing member which is parallel to the cable core and extends axially.

7. A method for preparing a fully dry overhead optical cable according to any one of claims 1 to 6, characterized in that: The following steps are involved: A foam glue is quantitatively coated on the outer side of the structure core, and a plurality of sleeve units are arranged circumferentially on the outer side of the structure core coated with the foam glue; The foamable adhesive foams and fills the gap between the adjacent sleeve units and the core of the structure, forming axially continuous convex ridges on the outer side of the core of the structure.

8. The method for preparing a fully dry overhead optical cable according to claim 7, characterized in that: A plurality of casing units are arranged circumferentially and longitudinally wrapped with water-blocking tapes to form a cable core, and water-blocking powder is adhered to the outer surface of the water-blocking tapes.

9. The method for preparing a fully dry overhead optical cable according to claim 7, characterized in that: The following steps are involved: The sheath material is extruded on the outside of the cable core to form an outer sheath.

10. The method for preparing a fully dry overhead optical cable according to claim 7, characterized in that: An 8-shaped sheath material is extruded outside the cable core and the reinforcement member parallel to the cable core to form an outer sheath.

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