Central tube type full-dry air-blowing belt cable and manufacturing method thereof

Abstract

The invention discloses a central tube type full-dry air-blowing belt cable, which comprises an optical fiber unit, an aramid yarn and an outer sheath, the optical fiber unit comprises an optical fiber ribbon matrix, a water-blocking tape and a loose tube, the loose tube comprises an inner layer and an outer layer, the inner layer and the outer layer are formed by a double-layer co-extrusion process, the inner layer and the outer layer are respectively made of a PC material and a PBT material, and the outer sheath is made of an aramid yarn. After the loose tube is formed through a co-extrusion process, the inner layer and the outer layer are pressed together through a vacuum sizing process, so that the interface bonding force of the inner layer and the outer layer is improved; the aramid yarn is wound on the loose tube and exerts winding force on the loose tube, so that the outer layer of the loose tube exerts pressure on the inner layer; the outer sheath wraps the aramid yarn. The vacuum sizing process is adopted to improve the bonding force of the interface of the inner layer and the outer layer, so that the inner layer and the outer layer are bonded more firmly, and the inner layer and the outer layer of the loose tube are further pressed together by means of the measure that the aramid yarn is tied outside the loose tube, so that the inner layer and the outer layer of the loose tube are prevented from being separated and misplaced during air blowing construction.

Description

Technical Field

[0001] The invention belongs to the field of optical cables, and more specifically, relates to a central tube type fully dry air-blown ribbon cable and a manufacturing method thereof. Background Art

[0002] Fiber ribbon cables are often called ribbon cables or ribbon cables. Center tube ribbon cables are characterized by light weight, small diameter, and low cost. If the number of optical fiber cores is not large, center tube ribbon cables are a better choice in the project. Center tube ribbon cables have strong temperature adaptability and can fully meet the use requirements of most scenarios.

[0003] The optical cable air blowing method uses high-pressure airflow to blow the optical cable into the pre-buried silicon core tube. The cable blowing machine blows high-pressure and high-speed compressed air into the silicon core tube, and the high-pressure airflow pushes the air blowing head, so that the air blowing head connected to the end of the optical cable forms a settable uniform pulling force on the optical cable. At the same time, the hydraulic crawler conveying mechanism of the cable blowing machine clamps the optical cable and conveys it forward to form a conveying force. The combination of pulling force and conveying force allows the inserted optical cable to quickly pass through the pipeline in a suspended state along with the high-speed airflow.

[0004] Loose tube is a tube in which optical fiber can be loosely placed in the optical cable to protect the optical fiber from internal stress and external side pressure. It is generally made of polypropylene or nylon. There are also optical fiber loose tubes made of PC and PBT materials. PC and PBT resins can be extruded and molded separately to form a double-layer loose tube with PC layer and PBT layer. However, in the double-layer loose tube, PBT is a crystalline polymer and PC is a non-crystalline polymer. The interface bonding between the two is poor. If a double-layer loose tube with PC layer and PBT layer is used in the central tube air-blown micro cable, the multi-layer structure from outside to inside of the central tube air-blown micro cable will be subjected to the same friction force in the circumferential direction during the air-blowing installation of the central tube air-blown micro cable, which is easy to separate the PC layer and the PBT layer and loosen and dislocate, destroying the complete structure of the optical cable and reducing the protective effect of the loose tube on the optical fiber. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the present invention provides a central tube type fully dry air-blown ribbon cable and a manufacturing method thereof, wherein the loose tube adopts a double-layer structure, and the loose tube adopts a vacuum sizing process to ensure the bonding force between the inner and outer layers, and the outer layer of the loose tube is wound with aramid yarn to allow the outer layer to further press the inner layer, further ensuring that the inner and outer layers will not separate and misalign during air-blowing construction.

[0006] To achieve the above object, according to one aspect of the present invention, a central tube type fully dry air-blown ribbon cable is provided, characterized in that it comprises an optical fiber unit, an aramid yarn and an outer sheath arranged in sequence from the inside to the outside, wherein:

[0007] The optical fiber unit comprises an optical fiber ribbon matrix, a water blocking tape and a loose tube arranged in sequence from the inside to the outside, the water blocking tape wraps the optical fiber ribbon matrix, the loose tube wraps the water blocking tape, the loose tube comprises an inner layer and an outer layer, and the inner layer and the outer layer are formed by a double-layer co-extrusion process, the inner layer and the outer layer are respectively made of PC material and PBT material, and the loose tube is formed by the co-extrusion process, and then the inner layer and the outer layer are pressed together by a vacuum sizing process to improve the interface bonding force between the inner layer and the outer layer;

[0008] The aramid yarn is wound on the loose tube and a winding force is applied to the loose tube, so that the outer layer of the loose tube applies pressure on the inner layer, thereby preventing the inner and outer layers of the loose tube from being separated during the air blowing construction of the central tube type full dry air blowing ribbon cable, thereby causing dislocation and delamination;

[0009] The outer sheath encases the aramid yarn.

[0010] Preferably, the pay-off tension of the aramid yarn is 3N-4N.

[0011] Preferably, the excess length of the optical fiber ribbon matrix is ​​+0.05% to +0.1%.

[0012] Preferably, the spiral pitch of the optical fiber ribbon matrix is ​​500mm-600mm, and the winding pitch of the aramid yarn is 500mm-600mm.

[0013] Preferably, an open cable is provided between the aramid yarn and the outer sheath.

[0014] Preferably, the outer sheath is made of HDPE material, and the thickness of the outer sheath is 0.35mm-0.5mm.

[0015] According to another aspect of the present invention, a method for manufacturing a central tube type fully dry air-blown ribbon cable is provided, characterized in that it comprises the following steps:

[0016] 1) Fiber coloring: A layer of ink is applied to the surface of each natural-colored optical fiber to distinguish different optical fibers by the color of the ink;

[0017] 2) Optical fiber ribbon matrix molding: After arranging the optical fibers in the order of color spectrum, a layer of resin is coated on the outside of the optical fibers, and then cured in a curing furnace to form an optical fiber ribbon matrix from the scattered optical fibers;

[0018] 3) Loose tube molding: The optical fiber ribbon matrix is ​​released from the pay-off frame according to the set tension, a layer of flexible water-blocking tape is wrapped around the optical fiber ribbon matrix, and then the inner and outer layers of the loose tube are extruded outside the water-blocking tape through a double-layer co-extrusion process;

[0019] 4) Vacuum sizing: The vacuum sizing process is used to ensure the bonding strength between the inner and outer layers of the loose tube;

[0020] 5) Winding aramid yarn: multiple aramid yarns are wound on the loose tube;

[0021] 6) Molding outer sheath: The outer sheath is formed by extruding on the outside of the aramid.

[0022] Preferably, in step 2), after the optical fiber ribbon matrix is ​​formed, coding is performed on the surface of each optical fiber ribbon to distinguish them.

[0023] Preferably, in step 3), the excess length of the optical fiber ribbon matrix in the loose tube is made to be +0.05%-+0.1% by controlling the pay-out tension of the optical fiber ribbon matrix, the pulling tension of the loose tube and the take-up tension.

[0024] Preferably, in step 5), the pay-off tension of each aramid yarn is consistent, so that the winding force applied by each aramid yarn to the loose tube is consistent.

[0025] In general, the above technical solution conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0026] 1) A central tube type fully dry air-blown ribbon cable of the present invention, the loose tube adopts an inner layer of PC material and an outer layer of PBT material, and its chemical properties, heat resistance, high impact resistance and molding shrinkage are all relatively appropriate, which ensures the compressive performance of the optical cable, and the low shrinkage and hardness of the PC material can not only effectively ensure the excess length of the optical fiber ribbon, but also effectively increase the air-blowing distance. The loose tube adopts a vacuum sizing process after the double-layer co-extrusion process to improve the bonding force at the interface between the inner layer and the outer layer, so that the inner layer and the outer layer are bonded more firmly, in addition, the loose tube is tied with aramid yarn outside, so that the outer layer of the loose tube applies pressure on the inner layer to bind the loose tube, further ensuring that the inner layer and the outer layer of the loose tube will not separate and dislocate during air-blowing construction.

[0027] 2) The central tube type fully dry air-blown ribbon cable of the present invention is reinforced with aramid yarn, so that the optical cable has good tensile resistance and can well adapt to the air blowing head pulling the optical cable forward in the air-blown micro-tube during air-blowing construction. In the preferred embodiment, the wound aramid yarn will be elongated and deformed when subjected to tension, which will apply greater pressure to the loose tube, and more tightly compress and bind the PBT outer layer to the PC inner layer to prevent separation, thereby playing a self-regulating role of "strengthening when encountering strong forces".

[0028] 3) The manufacturing method of the central tube type fully dry air-blown cable of the present invention is easy to operate and has high production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a central tube type fully dry air-blown cable in the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and 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] Reference Figure 1 A central tube type fully dry air-blown ribbon cable comprises an optical fiber unit, an aramid yarn 5 and an outer sheath 7 arranged in sequence from the inside to the outside, wherein:

[0032] The optical fiber unit comprises an optical fiber ribbon matrix 1, a water blocking tape 2 and a loose tube arranged sequentially from the inside to the outside, and a plurality of optical fiber ribbons are arranged as an optical fiber ribbon matrix 1, and the water blocking tape 2 wraps the optical fiber ribbon matrix 1, and the thickness of the water blocking tape 2 is preferably 0.15mm-0.18mm. The loose tube wraps the water blocking tape 2, and the loose tube comprises an inner layer 3 and an outer layer 4, and the inner layer 3 and the outer layer 4 are formed by a double-layer co-extrusion process, and the inner layer 3 and the outer layer 4 are respectively made of PC material and PBT material. After the loose tube is formed by the co-extrusion process, the interface bonding force of the inner layer 3 and the outer layer 4 is improved by a vacuum sizing process. The loose tube of the present invention adopts the design of the PC+PBT double-layer structure, which ensures the compressive performance of the optical cable, and the low shrinkage and hardness of the PC material can not only effectively ensure the excess length of the optical fiber ribbon matrix 1, but also effectively increase the distance of the air blowing.

[0033] The aramid yarn 5 is wound on the loose tube and applies a winding force to the loose tube, so that the outer layer 4 of the loose tube applies pressure on the inner layer 3, preventing the inner layer 3 and the outer layer 4 of the loose tube from being separated and causing dislocation and delamination during the air blowing construction of the central tube type full dry air blowing cable; the outer tube is reinforced with aramid, and the optical cable has good tensile properties. The aramid yarn 5 can make the inner layer 3 and the outer layer 4 of the loose tube more closely combined, preventing the inner layer 3 and the outer layer 4 from being separated and loosened during the air blowing laying of the air blowing cable. The pay-off tension of the aramid yarn 5 is 3N-4N, so that the aramid yarn 5 can not only apply a certain binding force to the loose tube, but also will not strangle the loose tube. The aramid yarn 5 is evenly arranged around the loose tube using a winding process.

[0034] The outer sheath 7 wraps the aramid yarn 5. The surface of the outer sheath 7 is relatively smooth, ensuring a smaller friction force when contacting the pipeline during the air blowing process.

[0035] Furthermore, the excess length of the optical fiber ribbon matrix 1 is +0.05%-+0.1%, so that when the optical cable is subjected to external forces, the optical fiber can obtain sufficient strain space so that the optical fiber will not be damaged by external forces.

[0036] Furthermore, the spiral pitch of the optical fiber ribbon matrix 1 is 500mm-600mm, and the winding pitch of the aramid yarn 5 is 500mm-600mm. The two pitches are equivalent, and the winding force on the loose tube is relatively uniform, ensuring that the inner layer 3 and the outer layer 4 of the loose tube are also uniformly stressed and not easy to separate.

[0037] Furthermore, a cable opening rope 6 is provided between the aramid yarn 5 and the outer sheath 7. The cable opening rope 6 is made of white 1670 polyester yarn. The cable opening rope 6 can tear the outer sheath 7, which is convenient for stripping the optical cable. The outer sheath 7 is preferably made of HDPE. The cable opening rope 6 ensures that the optical cable can be easily stripped. The thickness of the outer sheath 7 is only 0.35-0.5 mm. When stripping, it is only necessary to cut out a section of the polyester cable opening rope 6, and then the cable can be easily stripped directly with the polyester cable opening rope 6.

[0038] According to another aspect of the present invention, there is provided a method for manufacturing a central tube type fully dry air-blown ribbon cable, comprising the following steps:

[0039] 1) Fiber coloring: A layer of ink is applied to the surface of each natural-colored optical fiber to distinguish different optical fibers by the color of the ink;

[0040] 2) Fiber ribbon matrix 1 molding: After arranging the optical fibers in chromatographic order, a layer of resin is coated on the outside of the optical fibers, and the fibers are cured in a curing furnace to form a fiber ribbon matrix 1 from the scattered optical fibers; after forming the fiber ribbon matrix 1, the surface of each optical fiber ribbon is coded to distinguish them, such as spraying 1#, 2#, 3#, 4#, etc. to distinguish them, and coding and identification can also be performed according to customer requirements; specifically, the optical fibers are colored to form the fiber ribbon matrix 1, and a mold is used to coat a layer of resin on the outside of the optical fiber ribbon to arrange the optical fibers flatly. During the production of the fiber ribbon matrix 1, strict requirements are imposed on the flatness, thickness, width, etc. of the optical fibers. The fiber ribbon matrix 1 that comes out of the mold needs to be cured by ultraviolet light. The number of fiber ribbon cores can be 6F / 12F / 24F according to customer requirements;

[0041] 3) Loose tube molding: The optical fiber ribbon matrix 1 is released from the pay-off frame according to the set tension, a flexible water-blocking tape 2 is wrapped outside the optical fiber ribbon matrix 1, and then the inner layer 3 and the outer layer 4 of the loose tube are extruded outside the water-blocking tape 2 by a double-layer co-extrusion process, and a layer of PC material can be extruded outside the water-blocking tape 2 by a main extruder to form the inner layer 3 of the loose tube, and a layer of PBT material is extruded on the inner layer 3 by a color strip extruder to form the outer layer 4 of the loose tube, the thickness of the inner layer 3 is preferably 0.3mm, and the thickness of the outer layer 4 is preferably 0.1mm; By controlling the pay-off tension of the optical fiber ribbon matrix 1, the traction tension of the loose tube and the take-up tension, the excess length of the optical fiber ribbon matrix 1 in the loose tube is made to be +0.05%-+0.1%. In order to ensure the attenuation of the optical fiber, it is necessary to effectively control the excess length of the optical fiber ribbon matrix 1. By adjusting the pay-off tension of the optical fiber ribbon matrix 1, the auxiliary pulling tension of the loose tube, and the take-up tension, the excess length of the loose tube can meet the process requirements. Through effective control, the attenuation of the optical fiber is effectively controlled, and the core density of the optical cable can be significantly improved. The attenuation of the optical fiber at a wavelength of 1550 meets the standard of 0.22dB / km. After the loose tube is produced, the optical fiber attenuation test is required. Only the loose tube that passes the attenuation test can enter the next process.

[0042] According to the process, PP material is selected to make loose tubes. The optical fiber ribbon matrix 1 is installed on the rotating pay-off frame. In order to ensure the longitudinal water seepage performance of the loose tube, it is necessary to longitudinally wrap the water blocking tape 2 outside the optical fiber ribbon matrix 1. The thickness of the water blocking tape 2 is generally controlled at 0.15mm-0.18mm. When producing loose tubes, the pay-off tension of the optical fiber ribbon matrix 1, the twisted pitch of the optical fiber ribbon matrix 1, and the pay-off tension of the water blocking tape 2 are set according to the process. The loose tube production uses a drawing tube mold, and the drawing tube mold is installed flush. When the optical fiber ribbon matrix 1 longitudinally wrapped with the water blocking tape 2 enters the head, it will be wrapped by the double-layer co-extruded PC+PBT material to make a full dry loose tube. The loose tube is made of PC+PBT material, so that the loose tube has good compressive resistance, and also has good air blowing performance.

[0043] 4) Vacuum sizing: The bonding strength between the inner layer 3 and the outer layer 4 of the loose tube is ensured by the vacuum sizing process; the loose tube needs to adopt the vacuum sizing process during production, and the extruded loose tube needs to pass through the vacuum sizing die to make the inner layer 3 and the outer layer 4 of the loose tube tightly connected. Generally, the size of the vacuum sizing die is slightly larger than the diameter of the loose tube (generally 0.5mm). When the loose tube enters the entrance of the vacuum sizing die, the loose tube is preliminarily cooled by circulating water, and the vacuum water tank is sealed by a water ring, and then the water tank vacuum pump is turned on to extract the air in the water tank, and the negative pressure in the vacuum sizing water tank is adjusted by the vacuum negative pressure control valve. The greater the negative pressure, the better the inner layer 3 and the outer layer 4 are combined, but if the negative pressure is too large, it may cause the risk of the loose tube being broken. Therefore, as long as it can be ensured that the inner layer 3 and the outer layer 4 are not separated and loosened during air blowing construction, the loose tube is cooled after passing through the vacuum sizing water tank;

[0044] 5) Winding and releasing the aramid yarn 5: multiple aramid yarns 5 are wound on the loose tube; the pay-off tension of each aramid yarn 5 is consistent, so that the winding force applied by each aramid yarn 5 to the loose tube is consistent; specifically, according to different optical cable structures, the aramid yarn 5 adopts 1610 aramid or 3220 aramid, the type and number of aramid are designed according to the structure of the optical cable, and the aramid is evenly arranged around the tube using an aramid machine. The pay-off tension of aramid is generally controlled at 3-4N, and the twisting pitch of aramid is controlled at 500-600mm. The aramid twisting arrangement not only ensures the tensile performance of the optical cable, but also satisfies the bending performance of the optical cable. In the production process, the aramid must be evenly arranged, and the pay-off tension of each aramid must be kept consistent, so as to avoid bending of the optical cable during the production process and affect the appearance quality of the optical cable.

[0045] 6) Forming the outer sheath 7: Extruding the outer sheath 7 on the outside of the aramid fiber. The outer sheath 7 is made of HDPE material, and the thickness of the outer sheath 7 is 0.4mm-0.5mm. Therefore, the concentricity must be adjusted during the production of the sheath to ensure that the outer sheath 7 of the optical cable is not broken or damaged during the air blowing process. The HDPE material is evenly extruded around the cable core by an extruder. A mold is required during production. The mold core and the mold cover need to be installed flush. The concentricity of the mold needs to be adjusted before production. The thickness of the outer sheath 7 is generally controlled at 0.35-0.5mm. If the concentricity is not good, the outer sheath 7 will be stripped and broken during the production process. It is also possible that the outer sheath 7 will be broken during the air blowing process. At the same time, in order to ensure the air blowing effect, imported HDPE materials are used when producing the outer sheath 7. During the processing, the appropriate extrusion temperature and mold must be set to ensure that the surface of the optical cable is smooth. During the air blowing construction process, the friction between the surface of the outer sheath 7 of the optical cable and the pipeline is as small as possible.

[0046] 7) After the extruded air-blown cable is cooled in a water tank, it is necessary to spray a printed mark on the surface of the outer sheath 7. Because the wall thickness of the outer sheath 7 is relatively thin, only the inkjet method can be used. At the same time, the surface of the outer sheath 7 is relatively smooth, and the printed mark is not resistant to friction. It is necessary to use the method of inkjet coding on the machine head. During the cooling process of the outer sheath 7 in the water tank, the inkjet coding ink can penetrate into the surface of the outer sheath 7, so that the printed mark is resistant to friction, so as to avoid the printed mark being worn away when encountering external force during the construction process.

[0047] Furthermore, the pay-off tension of the optical fiber ribbon matrix 1 is 1.3N-1.8N, the auxiliary traction tension of the loose tube is 100N-150N, and the take-up tension of the air-blown ribbon cable is 25N-30N, so that the excess length of the optical fiber ribbon matrix 1 in the loose tube is +0.05%-+0.1%.

[0048] The fully dry air-blown cable provided by the present invention uses aramid as the main tensile element, and is reinforced with aramid yarn 5 inside, so that the excess length of the optical fiber ribbon and the elongation rate of the optical cable under the short-term allowable tension can be guaranteed to effectively avoid the tension of the optical fiber ribbon matrix 1 under the tension, avoid the increase of optical fiber transmission loss or fiber breakage caused by tension, and ensure the safe and reliable operation of the optical cable. Overall, the air-blown cable provided by the present invention has the advantages of simple structure, large number of optical fiber cores, and good tensile performance. Moreover, the aramid yarn 5 can exert a winding force on the loose sleeve, so that the inner layer 3 and the outer layer 4 of the loose sleeve are pressed tightly together. The present invention adopts a belt-type structural design, with large optical fiber capacity and high density, and the maximum number of optical cable cores can be 432. The present invention adopts a fully dry design, without adding water-blocking fiber paste and cable paste, which is clean and environmentally friendly; using an optical fiber ribbon structure, the construction efficiency is high

[0049] Optical fiber ribbon matrix 1 of the present invention comprises that multiple optical fiber ribbons adopt the optical fiber ribbon matrix 1 formed in a stacked manner, and coding is arranged on the optical fiber ribbon matrix 1 to distinguish, and water blocking tape 2 is coated outside the optical fiber ribbon matrix 1 bundle, so as to ensure the longitudinal water-proof performance of loose tube, and then the double-layer material of PC+PBT outer coat of water blocking tape 2 is formed into loose tube by extruder, and optical fiber ribbon matrix 1 is protected. Optical fiber ribbon matrix 1 has certain excess length in loose tube, so as to ensure the optical performance of optical fiber, and also ensure the tensile performance of optical cable. Aramid yarn 5 is wound around outside the loose tube again, and aramid yarn 5 is used as tensile element, so as to improve the tensile performance of optical cable, and then a layer of HDPE material is extruded outside aramid to form outer sheath 7, and the surface of optical cable is smooth and complete, so as to ensure air blowing performance. Optical cable structure of the present invention is simple, and optical cable is a full dry structure, and convenient construction and high construction efficiency of band structure meet environmental protection requirements. The optical cable is a central tube structure. Compared with the layer-twisted ribbon cable structure, the outer diameter of the optical cable is smaller. Under the current situation of tight pipeline resources, it saves pipeline resources and reduces engineering costs. At the same time, the optical cable adopts a central tube type, the optical cable is light in weight, and the air blowing distance of the optical cable is long, which effectively improves the efficiency of construction. The optical cable adopts a ribbon structure, with high fiber density, a large number of optical cable cores, and a large communication capacity, providing effective protection in big data and 5G communications.

[0050] 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 central tube type fully dry air-blown ribbon cable, characterized in that: It includes an optical fiber unit, an aramid yarn and an outer sheath arranged in sequence from the inside to the outside, wherein: The optical fiber unit comprises an optical fiber ribbon matrix, a water blocking tape and a loose tube arranged in sequence from the inside to the outside, the water blocking tape wraps the optical fiber ribbon matrix, the loose tube wraps the water blocking tape, the loose tube comprises an inner layer and an outer layer, and the inner layer and the outer layer are formed by a double-layer co-extrusion process, the inner layer and the outer layer are respectively made of PC material and PBT material, and the loose tube is formed by the co-extrusion process, and then the inner layer and the outer layer are pressed together by a vacuum sizing process to improve the interface bonding force between the inner layer and the outer layer; The aramid yarn is wound on the loose tube and a winding force is applied to the loose tube, so that the outer layer of the loose tube applies pressure on the inner layer, thereby preventing the inner and outer layers of the loose tube from being separated during the air blowing construction of the central tube type full dry air blowing ribbon cable, thereby causing dislocation and delamination; The outer sheath encases the aramid yarn.

2. The central tube type fully dry air-blown ribbon cable according to claim 1 is characterized in that: The pay-off tension of the aramid yarn is 3N-4N.

3. The central tube type fully dry air-blown ribbon cable according to claim 1, characterized in that: The excess length of the optical fiber ribbon matrix is ​​+0.05%-+0.1%.

4. The central tube type fully dry air-blown ribbon cable according to claim 1, characterized in that: The spiral pitch of the optical fiber ribbon matrix is ​​500mm-600mm, and the winding pitch of the aramid yarn is 500mm-600mm.

5. The central tube type fully dry air-blown ribbon cable according to claim 1, characterized in that: An open cable is arranged between the aramid yarn and the outer sheath.

6. The central tube type fully dry air-blown ribbon cable according to claim 1, characterized in that: The outer sheath is made of HDPE material, and the thickness of the outer sheath is 0.35mm-0.5mm.

7. A method for manufacturing a central tube type fully dry air-blown ribbon cable according to any one of claims 1 to 6, characterized in that: The following steps are involved: 1) Fiber coloring: A layer of ink is applied to the surface of each natural-colored optical fiber to distinguish different optical fibers by the color of the ink; 2) Optical fiber ribbon matrix molding: After arranging the optical fibers in the order of color spectrum, a layer of resin is coated on the outside of the optical fibers, and then cured in a curing furnace to form an optical fiber ribbon matrix from the scattered optical fibers; 3) Loose tube molding: The optical fiber ribbon matrix is ​​released from the pay-off frame according to the set tension, a layer of flexible water-blocking tape is wrapped around the optical fiber ribbon matrix, and then the inner and outer layers of the loose tube are extruded outside the water-blocking tape through a double-layer co-extrusion process; 4) Vacuum sizing: The vacuum sizing process is used to ensure the bonding strength between the inner and outer layers of the loose tube; 5) Winding aramid yarn: multiple aramid yarns are wound on the loose tube; 6) Molding outer sheath: The outer sheath is formed by extruding on the outside of the aramid.

8. The manufacturing method according to claim 1, characterized in that: In step 2), after the optical fiber ribbon matrix is ​​formed, coding is performed on the surface of each optical fiber ribbon to distinguish them.

9. The manufacturing method according to claim 1, characterized in that: In step 3), the excess length of the optical fiber ribbon matrix in the loose tube is made +0.05% to +0.1% by controlling the pay-off tension of the optical fiber ribbon matrix, the pulling tension of the loose tube and the take-up tension.

10. The manufacturing method according to claim 1, characterized in that: In step 5), the pay-off tension of each aramid yarn is consistent, so that the winding force applied by each aramid yarn to the loose tube is consistent.

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