Stranded optical cable having no binding yarn layer and manufacturing system and method therefor

Abstract

The present application relates to the technical field of optical communication transmission, and relates to a stranded optical cable having no binding yarn layer and a manufacturing system and method therefor. Said stranded optical cable comprises: a cable core, wherein the cable core comprises a central strength member and a plurality of loose buffer tubes, a plurality of optical fibers are arranged in the loose buffer tubes, and the loose buffer tubes are stranded on the surface the central strength member; and an outer sheath, wherein the outer sheath covers and is attached to the outside of the cable core, so that the cable core is directly bound by the outer sheath, in addition, a non-yarn water blocking element is filled between the central strength member and the loose buffer tubes, and a non-strip water blocking element is filled between the cable core and the outer sheath. No binding yarn is provided outside the cable core of said stranded optical cable of the present application, and there is no water-blocking yarn inside the cable core; compared with a binding-yarn optical cable, the optical cable has a higher roundness and a smaller diameter.

Description

A stranded optical cable without braiding, its manufacturing system, and manufacturing method [Technical Field]

[0001] This application belongs to the field of optical communication transmission technology, and more specifically, relates to a stranded optical cable without braiding and its manufacturing system and manufacturing method. [Background Technology]

[0002] With the surge in global data traffic and the diversification of internet applications, traditional optical cables face challenges in terms of transmission capacity and space utilization. Currently, traditional optical cables often use water-blocking yarn to bind the stranded core, or use a thin-film extrusion process to extrude a thin layer of thermoplastic elastomer (i.e., a film layer) instead of binding yarn during the SZ stranding process. However, under these manufacturing processes, the diameter of the optical cable is constrained by the binding layer and the film layer, making it particularly difficult to reduce the diameter of the optical cable. This results in optical cables that are usually thick, making it difficult to meet the increasingly stringent communication requirements of high-density cabling and ultra-thin optical cable designs. [Summary of the Invention]

[0003] The purpose of this application is to provide a non-braided stranded optical cable and its manufacturing system and method that overcome or mitigate the above-mentioned defects. This type of optical cable can have a very small diameter.

[0004] This application provides a stranded optical cable without binding yarn, specifically comprising:

[0005] The cable core includes a central reinforcing member and several loose tubes, with several optical fibers disposed inside the loose tubes, and the loose tubes are twisted to the surface of the central reinforcing member;

[0006] Outer sheath, which covers and fits the outside of the cable core, so that the cable core is directly bound by the outer sheath;

[0007] Meanwhile, the space between the central reinforcing member and the loose tube is filled with a non-yarn-type water-blocking element, and the space between the cable core and the outer sheath is filled with a non-strip-shaped water-blocking element.

[0008] Compared with the prior art, the cable core of this optical cable is directly bound by the outer sheath through the above-described technical solution conceived in this application. Compared with the braided optical cable, the overall roundness of this optical cable is higher, and the internal water-blocking elements can be selected in various ways. Compared with the braided optical cable and the thin film layer bound optical cable, the diameter of this optical cable can be made smaller and the cost of the optical cable can be made lower. This makes this optical cable particularly suitable for meeting the increasingly stringent communication needs such as high-density cabling and ultra-fine optical cable design.

[0009] As a further preferred embodiment, the cable core also includes a plurality of filler ropes, and the loose tube and the filler ropes are twisted together on the surface of the central reinforcement;

[0010] The non-yarn-type water-blocking element is filled between the central reinforcement, the loose sleeve, and the filler rope.

[0011] As a further preferred embodiment, the non-yarn-based water-blocking element is water-blocking powder or water-blocking grease.

[0012] As a further preferred embodiment, the non-strip water-blocking element is water-blocking powder, water-blocking grease, or water-blocking yarn.

[0013] As a further preferred embodiment, the material of the non-strip water-blocking element is the same as that of the non-yarn water-blocking element.

[0014] As a further preferred embodiment, both the non-strip water-blocking element and the non-yarn water-blocking element are made of water-blocking powder, and the particle size of the water-blocking powder is between 50um and 1000um.

[0015] As a further preferred embodiment, a cable-opening rope is provided between the cable core and the outer sheath, or a water-blocking yarn extending axially for cable opening is provided.

[0016] As a further preferred embodiment, the outer sheath has at least one tearable portion that extends axially along the outer sheath.

[0017] As a further preferred embodiment, the diameter of the loose sleeve is less than 1.5 mm and the wall thickness is less than 0.3 mm.

[0018] As a further preferred embodiment, the material used for the central reinforcement includes single-strand metal or fiber-reinforced composite material FRP; and / or,

[0019] The outer sheath is made of at least one of the following materials: polyethylene (PE), polyvinyl chloride (PVC), polyurethane (TPU), nylon (PA), and flame-retardant polyolefin low-smoke halogen-free (LZSH); and / or,

[0020] The loose sleeve is made of at least one of the following materials: polybutylene terephthalate (PBT), polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET), and thermoplastic polyester elastomer (TPEE); and / or,

[0021] The loose sleeve is either a dry type or an oil-filled type.

[0022] The manufacturing system provided in the second aspect of this application adopts the following technical solution:

[0023] A manufacturing system for manufacturing the unbundled stranded optical cable as described in the first aspect, comprising:

[0024] A line-laying device is used for laying out the central reinforcing member, m loose tubing and n filler ropes, where m≥1 and n≥0;

[0025] A vacuum water-blocking powder filling system is used for the twisted cable of the central reinforcing member, m loose tubes and n filling ropes and the negative pressure overfilling of water-blocking powder.

[0026] The extrusion head is used to extrude and form the outer sheath, and to directly bind the cable core with water-blocking powder during the extrusion process.

[0027] As a further preferred embodiment, the manufacturing system also includes a pre-twisting device disposed between the wire feeding device and the vacuum water-blocking powder filling system, for the initial twisting and shaping of the central reinforcing member, m loose tubes and n filling ropes.

[0028] As a further preferred embodiment, the manufacturing system also includes a pre-twisting device disposed between the wire feeding device and the vacuum water-blocking powder filling system, for the initial twisting and shaping of the central reinforcing member, m loose tubes and n filling ropes.

[0029] As a further preferred embodiment, the vacuum-sealed water-blocking powder filling system includes a negative pressure chamber, wherein:

[0030] The outlet end of the negative pressure chamber protrudes outward to form a pointed cable extrusion head, and the negative pressure chamber forms a tapered cable output port at the cable extrusion head.

[0031] The inlet end of the negative pressure chamber is equipped with a rotating cover with multiple perforations. The rotating cover is rotatably connected to the inlet end and is used to wind the central reinforcing member, m loose sleeves and n filling ropes that extend into the inner cavity of the negative pressure chamber along the perforations.

[0032] As a further preferred embodiment, the negative pressure chamber also has a powder inlet and a powder outlet, and the line formed between the powder inlet and the powder outlet intersects with the conveying trajectory of the central reinforcing member in the negative pressure chamber.

[0033] As a further preferred embodiment, the die head has an extrusion chamber, which has an outer sheath material feeding port and an extrusion port. The cable output port of the negative pressure chamber extends into the extrusion port of the extrusion chamber, and the cable output port is coaxial with the extrusion port.

[0034] As a further preferred embodiment, the system also includes an electrostatic generator for generating static electricity in the central reinforcing member at the inlet end of the negative pressure chamber;

[0035] Alternatively, the system may further include a media supply device for carrying a media for attaching water-blocking powder to the central reinforcement at the inlet end of the negative pressure chamber.

[0036] The manufacturing method provided in the third aspect of this application adopts the following technical solution:

[0037] A manufacturing method for manufacturing the unbundled stranded optical cable as described in the first aspect, comprising:

[0038] Provide one central reinforcing member, n filler ropes, and m loose tubes containing optical fibers, where m≥1 and n≥0;

[0039] In the negative pressure chamber, n filler ropes and m loose tubes are twisted together on the outer surface of the central reinforcement to form a cable core. An outer sheath is extruded at the cable outlet of the negative pressure chamber and wraps around the cable core. The outer sheath cools and shrinks, directly shaping and binding the cable core.

[0040] Water-blocking powder is filled into the negative pressure chamber between the central reinforcing member, n filling ropes, m loose tubes, and the outer surface of the formed cable core.

[0041] As a further preferred option, the central reinforcement is made to carry static electricity before filling with water-blocking powder, or the surface of the central reinforcement is made to carry a medium for adhering the water-blocking powder.

[0042] As a further preferred embodiment, during the filling of water-blocking powder, an excessive amount of water-blocking powder is continuously drawn into the negative pressure chamber, and then the excessive water-blocking powder adhering to the surface of the cable core is reduced and shaped through the cable output port of the negative pressure chamber, and the water-blocking powder that has not been filled into the optical cable is output through the powder output port of the negative pressure chamber.

[0043] As a further preferred embodiment, in this method, the outer sheath extruded at the extrusion port and the cable with water-blocking powder at the cable output port are coaxially output and integrally cooled and shaped, so that the outer sheath directly binds the cable core and the water-blocking powder, thereby producing a stranded optical cable without binding yarn.

[0044] In summary, compared with the prior art, the technical solutions conceived in this application have the following main technical advantages:

[0045] 1. The cable core in this optical cable is directly bound by the outer sheath. Compared with the braided optical cable, this optical cable has a higher overall roundness. The internal water-blocking elements can be selected in various ways. Compared with the braided optical cable and the film-layer bound optical cable, the diameter of this optical cable can be smaller and the cost of the optical cable can be lower. This makes this optical cable particularly suitable for meeting the increasingly stringent communication needs such as high-density cabling and ultra-fine optical cable design.

[0046] 2. In the manufacturing process of this optical cable, water-blocking powder is added during the stranding of the cable cores. Subsequently, the cable cores with water-blocking powder are coaxially output at the cable output port with the newly extruded outer sheath and cooled and shaped as a whole, so as to quickly produce a stranded optical cable without yarn binding. This process is fast and precise, and the finished optical cable has high stability. [Attached Image Description]

[0047] Figure 1 is a radial cross-sectional view of an unbundled stranded optical cable with internal non-yarn water-blocking elements and non-ribbon water-blocking elements made of the same material as an embodiment of this application.

[0048] Figure 2 is a radial cross-sectional view of an unbundled stranded optical cable with internal non-yarn water-blocking elements and non-ribbon water-blocking elements made of different materials, according to an embodiment of this application.

[0049] Figure 3 is a manufacturing process diagram of a stranded optical cable without braiding provided in an embodiment of this application.

[0050] Figure 4 is a schematic diagram of the process of covering the cable core with the outer sheath and water-blocking powder according to an embodiment of this application.

[0051] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 1. Outer sheath; 1-1. Tear-prone section; 2. Central reinforcement; 3. Loose tube; 4. Non-yarn water-blocking element; 5. Non-strip water-blocking element; 6. Cable release rope; 7. Cable feeder; 7-1. Central reinforcement cable feeder; 7-2. Loose tube cable feeder; 8. Tension dance wheel; 9. Windlass; 10. Vacuum water-blocking powder filling system; 11. Die head; 12. Extruder; 13. Water tank; 13-1. Anti-twist device; 14. Drying device; 15. Labeling machine; 16. Main traction device; 17. Take-up frame; 18. Negative pressure chamber; 18-1. Cable output port; 18-2. Powder inlet; 18-3. Powder outlet; 19. Static generator; 20. Rotary cap; 21. Extrusion chamber; 21-1. Extrusion port; 21-2. Outer sheath material discharge port.

Detailed Implementation Methods

[0052] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0053] The present application will be further described in detail below with reference to Figures 1-4.

[0054] This application discloses an unbundled stranded optical cable and its manufacturing system and method.

[0055] Referring to Figures 1-2, the unbundled stranded optical cable includes a cable core and an outer sheath 1. The cable core includes a central reinforcing member 2 and several loose tubes 3, each containing several optical fibers. The loose tubes 3 are stranded onto the surface of the central reinforcing member 2. The outer sheath 1 covers and adheres to the cable core, directly binding the cable core. Simultaneously, a non-yarn-type water-blocking element 4 fills the space between the central reinforcing member 2 and the loose tubes 3. A non-ribbed water-blocking element 5 fills the space between the cable core and the outer sheath 1.

[0056] Furthermore, the cable core may also include filler ropes, with the loose tubes 3 and filler ropes twisted together on the surface of the central reinforcement 2; and non-yarn-type water-blocking elements 4 are filled between the central reinforcement 2, the loose tubes 3, and the filler ropes. That is, in some embodiments, the cable core includes one central reinforcement 2, m loose tubes 3, and n filler ropes, where m ≥ 1 and n ≥ 0. The m loose tubes 3 and n filler ropes are twisted together on the surface of the central reinforcement 2; non-yarn-type water-blocking elements 4 are filled between the central reinforcement 2 and the m loose tubes 3 and n filler ropes. In some preferred embodiments, m + n ≥ 3.

[0057] Furthermore, the materials used for the central reinforcement 2 include, but are not limited to, single-strand metal or fiber-reinforced composite materials (FRP).

[0058] Furthermore, the materials used in the loose sleeve 3 include, but are not limited to, at least one of polybutylene terephthalate (PBT), polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET), and thermoplastic polyester elastomer (TPEE).

[0059] In addition, the loose sleeve 3 can be a dry loose sleeve or an oil-filled loose sleeve; the loose sleeve 3 is preferably a micro sleeve with a diameter of less than 1.5 mm, the number of cores per tube is preferably between 1 and 24, and the wall thickness of the loose sleeve 3 is preferably less than 0.3 mm. In some specific embodiments, the loose sleeve 3 can be a micro sleeve with a diameter of less than 1.0 mm.

[0060] Furthermore, m loose sleeves 3 and n filler ropes are twisted together on the surface of the central reinforcing member 2 by an SZ twisting method.

[0061] Furthermore, the non-yarn-based water-blocking element 4 can be water-blocking powder or water-blocking grease.

[0062] Furthermore, in some embodiments, the non-strip water-blocking element 5 can be at least one of water-blocking powder, water-blocking grease, or water-blocking yarn. In some embodiments, the material used for the non-strip water-blocking element 5 can be the same as the material used for the non-yarn water-blocking element 4, for example, both the non-strip water-blocking element 5 and the non-yarn water-blocking element 4 are made of water-blocking powder.

[0063] Furthermore, when the non-yarn-type water-blocking element 4 and / or the non-ribbon-type water-blocking element 5 are selected as water-blocking powder, the particle size of the water-blocking powder is preferably between 50um and 1000um. The water absorption capacity of the water-blocking powder is not less than 100g1 / g2, where g1 represents the weight of water and g2 represents the weight of water-blocking powder.

[0064] It is understandable that in the entire optical cable, the gap formed between the central reinforcing member 2 in the cable core and the m loose tubes 3 and n filler ropes is the inner filling gap, and the gap formed between the outer surface of the cable core and the loose tubes is the outer filling gap. Among them, the non-yarn water-blocking element 4 will fill the inner filling gap, while the non-ribbon water-blocking element 5 will fill the outer filling gap.

[0065] Furthermore, the outer sheath 1 is a sleeve that is extruded and molded around the cable core, then cooled, shrunk, and shaped to bind the cable core and water-blocking powder. The materials used for the outer sheath 1 include, but are not limited to, at least one of polyethylene (PE), polyvinyl chloride (PVC), polyurethane (TPU), nylon (PA), and flame-retardant polyolefin low-smoke halogen-free (LZSH).

[0066] Furthermore, in some embodiments, the outer sheath 1 may also have at least one tearable portion 1-1, which preferably extends along the axial direction of the outer sheath 1.

[0067] Furthermore, a cable-opening cord 6 may be provided between the outer surface of the cable core and the outer sheath 1, or a water-blocking yarn extending axially for cable opening may be provided. It should be noted that the design of the tear-resistant part 1-1, the cable-opening cord 6, and / or the water-blocking yarn is not mandatory. These designs can be added or removed according to actual usage requirements.

[0068] For ease of understanding, in a specific embodiment of a stranded optical cable without braiding as shown in Figure 1, the cable core includes a central reinforcing member 2 and six loose tubes 3, wherein the six loose tubes 3 are stranded on the outer surface of the central reinforcing member 2 in an SZ twisted manner. The outer sheath 1 of the optical cable has two tear-prone sections 1-1, which are symmetrically distributed radially. Furthermore, the optical cable is filled with non-ribbed water-blocking elements 5 and non-yarn-type water-blocking elements 4, both of which are water-blocking powder. In addition, a cable-opening cord 6 is filled between the outer surface of the cable core and the outer sheath 1.

[0069] In this design, the cable core is directly bound by the outer sheath 1. Compared with the braided optical cable, the overall roundness of this optical cable is higher. Compared with the braided optical cable and the film-layer bound optical cable, the diameter of this optical cable can be smaller and the cost of the optical cable can be lower. This makes this optical cable particularly suitable for meeting the increasingly stringent communication requirements such as high-density cabling and ultra-fine optical cable design.

[0070] Since there is no water-blocking yarn in the cable core, the loose tubes 3 will not be squeezed by the water-blocking yarn during the cabling process. All the loose tubes 3 are evenly distributed around the central reinforcing member 2. After the outer sheath 1 is squeezed out and cooled and shrank, the optical cable can still maintain its roundness and good shape at the turning point. Moreover, the cost of water-blocking powder is much lower than that of water-blocking yarn.

[0071] In addition, compared with the traditional solution of using thermoplastic elastomers (i.e. film layers) instead of yarn binding, this solution adopts a one-time forming process for the cable sheath, which saves the cost of the special material of film layer and eliminates the step of applying film layer, thereby reducing labor costs and improving manufacturing efficiency.

[0072] Particularly noteworthy is its application in the manufacturing of ultra-small diameter optical cables. This design can replace traditional yarn binding processes, enabling the stranding of thin-walled ultra-micro sheaths with diameters below 1.0 mm into SZ stranded cables. This technology solves the problems of unstable tension control, sheath damage leading to excessive attenuation, or subsequent excessive attenuation due to subsequent temperature cycling, after yarn binding is used in ultra-micro sheaths. It also addresses the issue of water-blocking yarn inside the cable core squeezing and damaging the sheath, causing excessive attenuation or subsequent excessive attenuation due to temperature cycling.

[0073] Further, referring to Figures 3-4, a manufacturing system for a non-bundled stranded optical cable is described. The system mainly includes: a pay-off device, a vacuum water-blocking powder filling system 10, a die head 11, an extruder 12, a water tank 13, a drying device 14, and a labeling machine 15. The pay-off device is used to pay off the central reinforcing member 2, m loose tubes 3, and n filler ropes 4, where m ≥ 1 and n ≥ 0; the pay-off device includes, but is not limited to, a pay-off frame. The stranding device is used for the initial stranding and shaping of the central reinforcing member 2, m loose tubes 3, and n filler ropes 4; the stranding device includes, but is not limited to, a stranding cage 9. The vacuum water-blocking powder filling system 10 is used for the stranding of the central reinforcing member 2, m loose tubes 3, and n filler ropes 4 into a cable and for the negative pressure overfilling of water-blocking powder. The extrusion head 11 is installed at the cable output port of the vacuum water-blocking powder filling system 10 and is used to extrude and form the outer sheath so that the cable core with water-blocking powder is directly bound during the extrusion and forming of the outer sheath.

[0074] Furthermore, for manufacturing unbundled stranded optical cables, one manufacturing method mainly includes:

[0075] A central reinforcing member 2, n filler ropes 4, and m loose tubes 3 containing optical fibers are provided, where m≥1 and n≥0. In a negative pressure chamber 18, the n filler ropes 4 and m loose tubes 3 are twisted on the outer surface of the central reinforcing member 2 to form a cable core. An outer sheath 1 is extruded at the cable output port 18-1 of the negative pressure chamber 18 and the outer sheath 1 wraps around the cable core. The outer sheath 1 cools and shrinks and directly shapes and binds the cable core. During the twisting of the n filler ropes 4 and m loose tubes 3 until the outer sheath 1 is covered, water-blocking powder is filled into the space between the central reinforcing member 2, the n filler ropes 4, the m loose tubes 3, and the outer sheath 1 by negative pressure in the negative pressure chamber 18.

[0076] For ease of understanding, the detailed components of this manufacturing system and the detailed manufacturing method of the optical cable are described below:

[0077] First, the central reinforcing member 2, m loose tubes 3, and n filler ropes 4 on each pay-off frame 7 (such as the central reinforcing member pay-off frame 7-1, the loose tube pay-off frame 7-2, etc.) are pulled through their respective tension rollers 8, and guided by the tension rollers 8 into the pre-twisting device for pre-twisting of the central reinforcing member 2, m loose tubes 3, and n filler ropes 4. The pre-twisting device includes, but is not limited to, using a auger 9. When the auger 9 is selected, it performs preliminary twisting and shaping of the central reinforcing member 2, n filler ropes 4, and m loose tubes 3 at a preset twisting pitch.

[0078] Subsequently, the central reinforcing member 2, n filler ropes 4 and m loose tubes 3 enter the vacuum water-blocking powder filling system 10 to add water-blocking powder and twist them into a cable core. Then, at the head 11 of the cable output port 18-1 of the system, the outer sheath 1 is extruded and formed by the extruder 12, so that the outer sheath 1 is extruded and formed and wrapped around the outer periphery of the cable core. The cable core and water-blocking powder are bound by cooling shrinkage and shaping to form a stranded optical cable without braiding.

[0079] After the outer sheath 1 is extruded, the optical cable passes sequentially through a water tank 13, a drying device 14, and a labeling machine 15. The optical cable is cooled by water in the water tank 13, dried by the drying device 14, and labeled by the labeling machine 15. Subsequently, the optical cable is pulled by the main traction device 16 and guided by the tension roller 8 at the rear end, causing it to be wound into the take-up frame 17. Preferably, the water tank 13 can also be equipped with an anti-twist device 13-1 to prevent the optical cable from twisting or reversing, which could lead to untwisting of the stranded loose tube.

[0080] Generally, the size and installation position of the tension dance wheel 8 can be selected based on the size of the material to be guided and the required tension. For example, if the loose sleeve 3 and the filler rope 4 are small and the required tension is low, then the corresponding tension dance wheel 8 can be integrated onto the pay-off frame 7 that winds up the loose sleeve 3 or the filler rope 4, and the tension dance wheel 8 can also be selected as a small-sized tension dance wheel 8. Conversely, if the central reinforcement or optical cable is large and the required tension is high, then the corresponding tension dance wheel 8 can be installed independently using a bracket or other structure, and a large-sized tension dance wheel 8 can be selected accordingly.

[0081] Specifically, as shown in Figure 3, in some specific embodiments, the vacuum water-blocking powder filling system 10 includes a negative pressure chamber 18, and an electrostatic generator 19 is provided at the inlet end of the negative pressure chamber 18. The electrostatic generator 19 can generate static electricity in the central reinforcing member 2 so that after the central reinforcing member 2 enters the negative pressure chamber 18, water-blocking powder is attached by electrostatic adsorption.

[0082] Of course, in other embodiments, a medium supply device can also be provided at the inlet end of the negative pressure chamber 18. The medium supply device carries a medium capable of adhering to water-blocking powder on the central reinforcing member 2, so that the water-blocking powder adheres to the central reinforcing member 2. For example, the medium supply device includes a water mist generator, which sprays water mist onto the central reinforcing member 2. After the central reinforcing member 2 enters the negative pressure chamber 18, the water-blocking powder adheres to the central reinforcing member 2 through surface moisture.

[0083] Furthermore, as shown in Figure 3, a rotating cap 20 with multiple perforations is installed at the inlet end of the negative pressure chamber 18, and a pointed cable extrusion head protrudes outward from the outlet end of the negative pressure chamber 18. A constricted cable output port 18-1 is formed at the cable extrusion head of the negative pressure chamber 18. The rotating cap 20 is rotatably connected to the inlet end, and its rotation axis is coaxial with the transverse axis of the negative pressure chamber. The rotating cap 20 can rotate in conjunction with the SZ winding process of the winch 9 to wind the central reinforcing member 2, n filling ropes 4, and m loose tubes 3 that are inserted into the negative pressure chamber 18 through the perforations.

[0084] Furthermore, the negative pressure chamber 18 has a powder inlet 18-2 and a powder outlet 18-3, enabling it to be used as a water-blocking powder filling chamber. Preferably, the line connecting the powder inlet 18-2 and the powder outlet 18-3 in the negative pressure chamber 18 intersects the conveying trajectory of the central reinforcement 2 (or the length direction or extension direction of the central reinforcement 2). In some embodiments, multiple sets of powder inlets 18-2 and powder outlets 18-3 can be provided in the negative pressure chamber 18. For example, in addition to the powder inlets 18-2 and powder outlets 18-3 shown in FIG. 3, powder inlets 18-2 and powder outlets 18-3 can be added at the cable extrusion head to further fill the water-blocking powder.

[0085] Furthermore, the powder inlet 18-2 of the negative pressure chamber 18 is connected to a powder metering conveying device via a pipe. This device supplies water-blocking powder into the negative pressure chamber 18. The powder outlet 18-3 of the negative pressure chamber 18 is connected to a discharge pipe equipped with a blower. The blower creates negative pressure in the negative pressure chamber 18, extracting excess water-blocking powder and achieving directional conveying of the water-blocking powder within the chamber. For ease of understanding, the conveying direction of the water-blocking powder is roughly indicated by hollow arrows in Figure 3.

[0086] In addition, a centrifugal separation and filtration system can be installed on the discharge pipe for filtering and recovering water-blocking powder; the centrifugal separation and filtration system is preferably installed at the suction end of the blower to prevent water-blocking powder from entering the centrifugal blower and avoid dust explosion.

[0087] Furthermore, the die head 11 is also provided with an extrusion chamber 21 at the outlet end of the negative pressure chamber 18. The extrusion chamber 21 has an outer sheath material feeding port 21-2 and an extrusion port 21-1. The cable output port 18-1 of the negative pressure chamber 18 extends into the extrusion port 21-1 of the extrusion chamber 21, and the cable output port 18-1 is coaxial with the extrusion port 21-1. The outer sheath material feeding port 21-2 is connected to the extruder 12. The extruder 12 can extrude sheath material into the extrusion chamber 21 along the outer sheath material feeding port 21-2, so that the sheath material is extruded at the extrusion port 21-1 to form the outer sheath 1.

[0088] During use, an excessive amount of water-blocking powder is continuously fed into the negative pressure chamber 18 through a powder metering system. Then, the excess water-blocking powder adhering to the surface of the cable core is reduced and shaped through the inner wall of the cable output port 18-1 of the negative pressure chamber 18. The water-blocking powder that is not filled into the optical cable is output through the powder output port 18-3 of the negative pressure chamber 18. Meanwhile, the extruder 12 extrudes the outer sheath 1 at the extrusion port 21-1 of the extrusion chamber 21. The outer sheath 1 extruded at the extrusion port 21-1 is coaxially output with the cable core containing water-blocking powder at the cable output port 18-1 and cooled and shaped as a whole. This allows the outer sheath 1 to directly bind the cable core and the water-blocking powder, resulting in a stranded optical cable without binding yarn.

[0089] It is clear that the fans, extruders, and other mechanisms / equipment / devices in this optical cable manufacturing system can be controlled by a control terminal to achieve automated and controllable operation. The control principle is existing technology and will not be elaborated on here.

[0090] It should be understood that expressions such as "comprising" and "may include" as used in this application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In this application, terms such as "comprising" and / or "having" may be interpreted as indicating a specific characteristic, number, operation, constituent element, component, or combination thereof, but should not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0091] It should be understood that the terms “center,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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. Therefore, they should not be construed as limitations on this application.

[0092] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0093] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral 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; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0094] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A layer- free stranded optical cable characterized by comprising: include: The cable core includes a central reinforcing member (2) and several loose tubes (3), and several optical fibers are disposed inside the loose tubes (3). The loose tubes (3) are twisted to the surface of the central reinforcing member (2). Outer sheath (1), the outer sheath (1) covers and fits the outside of the cable core, so that the cable core is directly bound by the outer sheath (1); Meanwhile, a non-yarn-type water-blocking element (4) is filled between the central reinforcing member (2) and the loose tube (3), and a non-strip-shaped water-blocking element (5) is filled between the cable core and the outer sheath (1).

2. The layer-free stranded optical cable of claim 1, wherein The cable core also includes several filler ropes, and the loose tube (3) and the filler ropes are twisted together on the surface of the central reinforcing member (2); The non-yarn-type water-blocking element (4) is filled between the central reinforcing member (2), the loose sleeve (3), and the filling rope.

3. The layer- free stranded optical cable according to claim 1 or 2, characterized in that, The non-yarn-type water-blocking element (4) is water-blocking powder or water-blocking grease.

4. The unbundled stranded optical cable as described in claim 1, characterized in that, The non-strip water-blocking element (5) is water-blocking powder, water-blocking grease, or water-blocking yarn.

5. The unbundled stranded optical cable as described in claim 1, characterized in that, The material of the non-strip water-blocking element (5) is the same as that of the non-yarn water-blocking element (4).

6. The unbundled stranded optical cable as described in claim 5, characterized in that, The material of the non-strip water-blocking element (5) and the non-yarn water-blocking element (4) are both water-blocking powders, and the particle size of the water-blocking powders is between 50um and 1000um.

7. The unbundled stranded optical cable as described in claim 1 or 2, characterized in that, A cable-opening rope (6) is provided between the cable core and the outer sheath (1), or a water-blocking yarn that extends axially and can be used for cable opening is provided.

8. The unbundled stranded optical cable as described in claim 1 or 2, characterized in that, The outer sheath (1) has at least one tearable portion (1-1) that extends along the axial direction of the outer sheath (1).

9. The unbundled stranded optical cable as described in claim 1 or 2, characterized in that, The diameter of the loose sleeve (3) is less than 1.5 mm and the wall thickness is less than 0.3 mm.

10. The unbundled stranded optical cable as described in claim 1 or 2, characterized in that, The outer sheath (1) is made of at least one of the following materials: polyethylene (PE), polyvinyl chloride (PVC), polyurethane (TPU), nylon (PA), and flame-retardant polyolefin low-smoke halogen-free (LZSH); and / or, The material used for the central reinforcement (2) includes single-strand metal or fiber-reinforced composite material FRP; and / or, The loose sleeve (3) is made of at least one of polybutylene terephthalate (PBT), polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET), and thermoplastic polyester elastomer (TPEE); and / or, The loose sleeve (3) is a dry or grease-filled loose sleeve.

11. A manufacturing system for manufacturing unbundled stranded optical cables, characterized in that, include: A wire-laying device is used for laying out the central reinforcing member (2), m loose tubes (3) and n filler ropes (4), where m≥1 and n≥0; A vacuum water-blocking powder filling system (10) is used for the twisted cable of the central reinforcing member (2), m loose tubes (3) and n filling ropes (4) and the negative pressure overfilling of water-blocking powder. The extrusion head (11) is used to extrude and form the outer sheath (1), and to directly bind the cable core with water-blocking powder during the extrusion forming of the outer sheath (1).

12. The manufacturing system as claimed in claim 11, characterized in that, The manufacturing system also includes a pre-twisting device, which is located between the wire feeding device and the vacuum water-blocking powder filling system (10) for the initial twisting and shaping of the central reinforcing member (2), m loose tubes (3) and n filling ropes (4).

13. The manufacturing system as claimed in claim 11, characterized in that, The vacuum-sealed water-blocking powder filling system (10) includes a negative pressure chamber (18), wherein: The outlet end of the negative pressure chamber (18) protrudes outward to form a pointed cable extrusion head, and the cable extrusion head forms a tapered cable output port (18-1). The inlet end of the negative pressure chamber (18) is equipped with a rotating cover (20) with multiple perforations. The rotating cover (20) is rotatably connected to the inlet end to be used to twist together the central reinforcing member (2), m loose tubes (3) and n filler ropes (4).

14. The manufacturing system as claimed in claim 13, characterized in that, The negative pressure chamber (18) also has a powder inlet (18-2) and a powder outlet (18-3), and the line formed between the powder inlet (18-2) and the powder outlet (18-3) intersects with the conveying trajectory of the central reinforcing member (2) in the negative pressure chamber (18).

15. The manufacturing system as claimed in claim 13, characterized in that, The head (11) has an extrusion chamber (21), which has an outer sheath material feeding port (21-2) and an extrusion port (21-1). The cable output port (18-1) of the negative pressure chamber (18) extends into the extrusion port (21-1), and the cable output port (18-1) is coaxial with the extrusion port (21-1).

16. The manufacturing system as claimed in claim 11, characterized in that, The system also includes an electrostatic generator (19) for generating static electricity in the central reinforcing member (2) at the inlet end of the negative pressure chamber (18); Alternatively, the system may further include a media supply device for carrying a media for attaching water-blocking powder to the central reinforcement (2) at the inlet end of the negative pressure chamber (18).

17. A manufacturing method for manufacturing unbundled stranded optical cables, characterized in that, include: Provide one central reinforcing member (2), n filler ropes (4) and m loose tubes containing optical fibers (3), where m≥1 and n≥0; In the negative pressure chamber (18), n filler ropes (4) and m loose tubes (3) are twisted together on the outer surface of the central reinforcement (2) to form a cable core. An outer sheath (1) is extruded at the cable outlet (18-1) of the negative pressure chamber (18), and the outer sheath (1) wraps around the cable core. The outer sheath (1) cools and shrinks, directly shaping and binding the cable core. Water-blocking powder is filled in the negative pressure chamber (18) between the central reinforcing member (2), n filling ropes (4), m loose tubes (3), and the outer surface of the formed cable core.

18. The manufacturing method as described in claim 17, characterized in that, Before filling with water-blocking powder, make the central reinforcement (2) carry static electricity, or make the surface of the central reinforcement (2) carry a medium for adhering the water-blocking powder.

19. The manufacturing method as described in claim 17, characterized in that, When filling the water-blocking powder, an excessive amount of water-blocking powder is continuously sucked into the negative pressure chamber (18). Then, the excessive water-blocking powder adhering to the surface of the cable core is reduced and shaped through the inner wall of the cable output port (18-1) of the negative pressure chamber (18), and the water-blocking powder that has not been filled into the optical cable is output through the powder output port (18-3) of the negative pressure chamber (18).

20. The manufacturing method according to any one of claims 17-19, characterized in that, In the manufacturing method, the outer sheath (1) extruded at the extrusion port (21-1) and the cable core with water-blocking powder at the cable output port (18-1) are coaxially output and cooled and shaped as a whole, so that the outer sheath (1) directly binds the cable core and water-blocking powder, and a stranded optical cable without binding yarn is produced.

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