RU136900U1 - FIBER OPTICAL CABLE NAVY - Google Patents

Abstract

The invention relates to the construction of suspended fiber-optic communication cables, in particular, designed for suspension by winding onto a supporting element when creating FTTH aerial networks. A design of coiled fiber optic cable with miniature transverse dimensions is proposed. FIG. 3, the use of which reduces material and time costs in the construction and maintenance of FTTH air networks. A coiled fiber optic cable, the materials and construction of which allow it to be used outdoors, containing at least one telecommunication optical fiber and a plastic sheath, is characterized in that it contains one longitudinal rigid power element that prevents compression and bending, one optical module, covering all optical fibers of the cable, longitudinal flexible power elements that prevent stretching, in the form of at least one strand, has transverse dimensions limited to 5 mm, and also It can be completely dielectric.

Description

The technical field to which the utility model relates.

The invention relates to fiber-optic communication cables, namely, to designs of suspended fiber-optic communication cables, in particular, intended for suspension by winding onto a carrier element when creating FTTH aerial networks (optical fiber is brought into the house to the subscriber).

State of the art

The main component of FTTH networks, affecting the cost of connecting subscribers, is the cable system. Aerial cable system is much more economical than underground. During the construction of FTTH aerial networks in low-rise areas, distribution and subscriber fiber-optic cables are suspended in the spans between the supports of the overhead telecommunication line and / or the supports of the overhead power transmission line (OHL) and / or the outdoor lighting poles and / or the supports of the contact network , and / or between buildings and / or structures. Due to the need to suspend a relatively large number of FTTH cables in the spans, on the one hand, and the limited space for suspension on the existing infrastructure, on the other hand, it is required to use a cable system with the possibility of compact suspension. For the effectiveness of an overhead cable system, it is also required that the FTTH network overhead cables have the ability to enter into the building and lay along internal walls, under baseboards, in ducts, cable ducts, etc., allow small bending radii without increasing the attenuation of the optical signal in the fiber, and also had the technical ability to terminate with standard optical connectors with installation directly on the cable. An important factor is the small transverse dimensions of the cables, in particular to reduce the material consumption of the cables, reduce the size of the bays of technological stock, ease of wiring indoors and to simplify termination with standard optical connectors. To suspend FTTH network fiber optic cables on overhead power transmission towers, it is necessary to comply with electrical installation rules, which in particular require fiber optic cables to be dielectric. When openly routing indoor fiber optic cables, it may be necessary that the cable sheath produces little smoke when heated and does not contain halogens. Attaching optical connectors to the ends of a single-fiber cable designed to connect a subscriber to an FTTH network is greatly simplified if the cable has flexible power elements, such as aramid threads. Important is the compatibility of the cable design with standard cable clamps, in particular with wedge clamps, which greatly simplify cable suspension and setting its sag.

The prior art design of a fiber optic overhead cable, proposed, in particular, for the connection section of subscribers of the FTTH network (drop cable), which contains two rigid power elements located on either side of one or more optical fibers, and has an additional remote a power element used to suspend cable on supports (US Pat. No. 6,728,455 of April 27, 2004, Fujikura Ltd.). The cable has small transverse dimensions and is easy to manufacture. For its suspension, clamps of a simplified design are used. The cable is easy to cut. The disadvantage of this design is that the remote power element is either made in the form of a steel wire, which makes the cable non-dielectric, or not strong enough for suspension in spans of typical lengths, for example, between OHL supports. The cable design does not allow its use in a wide temperature range, in particular, the cable may not be applicable in climatic zones with a temperature minimum of minus 40 ° C or lower.

Another design of a fiber optic overhead cable contains one dielectric rigid power element and one optical module containing optical fibers (US Pat. No. 6,928,217 of 08/09/2005, Corning Cable Systems LLC). The design of the cable simplifies its production. The disadvantage of this design is that to ensure the necessary length of the free suspension, a power element of such strength is required that is achieved with large transverse dimensions of the power element, which leads to an increase in the transverse dimensions of the cables and to a decrease in its flexibility. This, in particular, makes it difficult to lay the cable indoors and creates difficulties when terminating the cable with standard optical connectors.

Similar disadvantages of the above design have the design of a fiber optic flat cable with two rigid power elements and one optical module between them (US patent No.6,542,674 from 04/01/2003, Corning Cable Systems LLC), but this design has better flexibility in one direction. In addition, if the power elements have a transverse dimension close to or greater than the diameter of the optical module, they protect it from the effect of crushing force perpendicular to the plane of the cable. This makes it possible to use wedge clamps with its free suspension, into which the cable is inserted completely in the place of fastening.

The prior art methods of suspension of fiber optic cables on a carrier element, in particular, fiber optic cables can be wound on a carrier element, which acts as a wire or cable (US patent No.4,715.582 from 12/29/1987, Furukawa Electric Co.) . At the same time, the requirements for the allowable stretching of coiled fiber optic cables are significantly reduced, but at the same time the requirements for their flexibility, as well as for the smallness of their linear weight and transverse dimensions, are increasing.

A design in which a fiber-optic cable has two rigid tensile, compressive, and bend power elements, flexible tensile forces together with rigid, and one optical module (US Pat. No. 8,355,613 of January 15, 2013, OFS Fitel , LLC) allows you to increase the value of the allowable stretching and at the same time increase the flexibility of the cable. An optical module with loose fiber laying can be used in the cable. Rigid power elements provide cable operation in a given temperature range, ensuring application in various climatic zones. The presence of a flexible power element allows you to reduce the transverse dimensions of the cable while maintaining the possibility of free suspension and this allows you to have bays of technological stock of small sizes, facilitates laying indoors, makes it possible to directly terminate the cable with standard optical connectors. The cable is dielectric, may not contain halogens and emit little smoke when heated. A cable of this design can be suspended by winding on a supporting element. The disadvantage of this design is the excessive complexity due to the fact that the rigid elements are not one, but two. Another disadvantage of the design with two rigid elements is that for flexibility it is required that the rigid power elements have small transverse dimensions, and this does not allow them to protect the optical module from crushing. This technical solution is the closest among the known to the proposed utility model for a combination of features.

Utility Model Disclosure

The task was to develop the design of an economical fiber-optic cable for primary use as an overhead coiled cable for FTTH aerial networks, but not limited to this application. The cable should be characterized by small transverse dimensions, sufficient tensile strength for free suspension, resistance to longitudinal and lateral loads, flexibility and resistance to bending, the ability to function in outdoor conditions in a wide temperature range, be able to lay indoors, be dielectric, be convenient for terminate it with standard optical connectors and be compatible with widely used wedge clamps in case of freedom of suspension.

The technical result of the utility model consists in obtaining the design of a coiled fiber optic cable with miniature transverse dimensions, the use of which leads to a reduction in material and time costs in the construction and maintenance of FTTH air networks.

The technical result is achieved in that the fiber-optic cable is coiled, the materials and construction of which allow it to be used in outdoor conditions, containing at least one optical fiber designed to transmit information and a plastic sheath, characterized in that it contains one longitudinal rigid power element , preventing compression and bending, one optical module, covering all optical fibers of the cable, longitudinal flexible power elements that prevent stretching, in the form of at least one and contains no metal or other conductive components and has transverse dimensions, the limited size of 5 mm (hereinafter lock seam OK).

This design makes it possible to produce miniature dielectric fiber cables for hanging them by winding them with a special winding device onto a cable, wire or cable located on the existing infrastructure of overhead power lines, overhead telephone and telecommunication lines, etc., which speeds up and cheapens the construction of overhead networks FTTH.

In one embodiment of the utility model of Navivny OK, a fiberglass (a plastic bar reinforced with fiberglass) is used as the only rigid dielectric power element. In another embodiment of the utility model, an aramid rod (a plastic rod reinforced with aramid fibers) is used as the only rigid dielectric power element. A rigid force element counteracts the longitudinal compression of the cable upon cooling, limits the bending radius and counteracts the stretching of the cable when it is tensioned or when heated. In particular, the rigid power element and cable design allow the use of the cable in a wide temperature range, for example, the cable can be used in climatic zones with a temperature minimum of minus 40 ° C and below.

In yet another embodiment of the utility model, at least one yarn containing glass fibers (glass fiber) is used as flexible power elements. In yet another embodiment of the utility model, at least one yarn containing aramid fibers (aramid yarn) is used as flexible force elements. In addition to the rigid one, flexible power elements counteract the cable stretching when it is stretched or when heated, which allows for the same maximum permissible tensile load to have a rigid power element with a smaller cross-sectional area compared to the cross-sectional area of a rigid power element in the cable, which has only power element and no flexible. The smaller transverse dimensions of the rigid power element give greater flexibility of the cable, which is important when using the cable as a winding cable. A flexible power element, a rigid power element and cable design determine its maximum allowable tensile load, which must meet the generally accepted requirements for fiber-optic communication cables. For example, for free suspension in typical spans from poles to houses, it may be required that the maximum allowable tensile load exceeds 0.3 kN. This, in particular, is determined by the area of use and the maximum span in which the cable is supposed to be suspended freely (without attaching to the supporting element). A flexible power element, if it has sufficient strength, can be used when cutting the cable to break the sheath and / or to attach optical connectors to the ends of the cable.

In yet another embodiment of the utility model, the cable comprises at least one water blocking thread. Hydrophilic components of a water-blocking thread when water enters the cable due to violation of the integrity of the outer sheath increases several times in volume and prevents the longitudinal distribution of water in the cable, in particular along the threads of flexible power elements.

In another embodiment of the utility model, the cable uses single-mode telecommunication fibers that are insensitive to bending. This, in particular, makes it possible to run the cable into the premises of the subscriber of the FTTH network and lay it indoors, observing less stringent requirements on bending radii than for a cable with standard fibers.

In another embodiment of the utility model, the optical module is made in the form of a tube with free laying of fibers in it. Such a module allows for the operation of a cable containing one or more optical fibers in a wide temperature range.

In another embodiment of the utility model, if the cable contains one fiber, the optical module is made in the form of a sheath, tightly covering the fiber and having an outer diameter of 900 microns. This, in particular, facilitates cable termination with standard optical connectors.

In another embodiment of the utility model, the cable sheath consists of plastic that emits little smoke when heated, and does not contain halogens. This, in particular, makes it possible to lay the cable indoors in an open way, without violating generally accepted fire safety rules.

In yet another embodiment of the utility model, a rigid power element and an optical module are arranged in parallel and have a longitudinal touch line. In this case, the most compact installation of cable components is achieved.

In yet another embodiment of the utility model, the optical module has a circular cross section, and the transverse dimension of the rigid power element along an axis perpendicular to the plane passing through the center lines of the optical module and the rigid power element is greater than or approximately equal to the diameter of the optical module. At the same time, the power element additionally protects the optical module from crushing, for example, if wedge clamps are used for free suspension of the cable, completely covering the cable at the fixing point.

In yet another embodiment of the utility model, the cable has a cross section close to rectangular, which is more convenient for applying wedge clamps and winding the cable into tight bays with a row layout.

Brief Description of the Drawings

FIG. 1 - Cross section of Navivny OK with an optical module with free laying of optical fibers, for which the diameter of the module exceeds the diameter of the rigid power element (Option No. 1);

FIG. 2 - Cross section of Navivny OK with an optical module with a diameter of 900 μm with a tight coverage of one optical fiber with a shell of the module for which the diameter of the rigid power element exceeds the diameter of the module (Option No. 2);

FIG. 3 - Cross section of Navivny OK with an optical module with free laying of optical fibers, for which the diameter of the module is approximately equal to the diameter of a rigid power element. (Option No. 3).

In the figures:

1 - the outer sheath of the cable;

2 - hard power element;

3 - threads of flexible power elements containing fiberglass or aramid fibers;

4 - the shell of the optical module with free laying of fibers;

5 - optical fibers with a diameter of 250 microns;

6 - module shell with an outer diameter of 900 μm with a dense coverage of one optical fiber;

7 - hydrophobic gel filling module.

Utility Model Implementation

The main application of Navivny OK is the construction of FTTH air networks for areas of private residential development, including in cottage and summer cottages. Such networks typically consist of backbone, distribution, and subscriber branches. Navivnoy OK is used in the distribution part and for subscriber taps.

In the distribution part of the FTTH network, Navivnaya OK is used to connect subscriber connection couplings (drop-couplings) to the distribution cabinet. In this use case, Navivnaya OK contains from four to eight single-mode optical fibers. A coiled OK is suspended by coiling using a special device to a self-supporting fiber-optic cable or cable, forming a dense bundle.

When used as a FTTH network subscriber, Navivnaya OK contains from one to four single-mode optical fibers. In this case, Navivnaya OK is suspended by winding from a distribution cabinet or drop clutch to a support located in the vicinity of the subscriber’s house. From this support to the subscriber’s house, the subscriber can be suspended as a self-supporting cable or wound onto a cable, or pulled into a protective polyethylene pipe laid in the ground.

Variants of implementation of Navivny OK (hereinafter Variants No.№) shown in FIG. 1, FIG. 2, FIG. 3, as examples, but not limited to, the following.

For Option # 1, schematically shown in FIG. 1, fiberglass 2 of circular cross section with a diameter of 1 mm is used as a rigid power element. Four aramid yarns 3 with a density of 1600 dtex are used as flexible power elements. They are arranged on different sides of the touch line of the fiberglass and optical module 4. The module is a tube made of polybutylene terephthalate (PBT) with an external diameter of 1.6 mm and an inner diameter of 1 mm. From one to eight optical fibers 5 with a diameter of 250 μm freely fit into the module. The module is filled with hydrophobic gel 7. The cable has a transverse dimension of 2.5 mm by 3.5 mm.

For Option # 2, schematically shown in FIG. 2, module 6 with an outer sheath diameter of 900 μm tightly covers one optical fiber 5, while the cable has a transverse dimension of 2 mm by 3 mm.

The cable of Option No. 1 has an operating temperature range of no worse than from minus 40 ° С to plus 70 ° С, and the cable of Option No. 2 is no worse than from minus 20 ° С to plus 70 ° С. The maximum allowable tensile load in both versions exceeds 0.35 kN. Cable sheath 1 of Options No. 1 and No. 2 may be made of medium or high density polyethylene, ensuring its use in outdoor conditions. Another option is LSZH (low-smoke, halogen-free) plastic, stabilized to counteract ultraviolet radiation. In some cases, the implementation of Options No. 1 and No. 2, optical fibers of the G.657A1 standard are used, which allows bending of a cable with a radius of 10 mm or more. In other cases of the implementation of Options No. 1 and No. 2, optical fibers of the G.657A2 standard are used, which allows bending of a cable with a radius of 7 mm or more. A smaller bending radius does not allow fiberglass.

For Option No. 1, the cable bay with a length of 100 m has, in particular, the following dimensions: diameter 210 mm, width 35 mm and weight 930 g, and for Option No. 2-185 mm, 35 mm and 670 g, respectively. Such dimensions and weight make it possible to use a small winding device for both cable options, easily installed manually on a carrier cable or a cable on which the winding is carried out.

For cable of Option No. 1, you should use ring clamps with its free suspension, which is a container in the form of two nested cylinders, between which three to five turns of cable are wound, which self-tighten when tensioned.

In Option No. 2, the diameter of the fiberglass is larger than the diameter of the optical module, and with free suspension of the cable, wedge clamps can be applied, which consist of a housing and a wedge, between which the cable is clamped. The cable pulls the wedge into the housing under tension and is thereby held even more firmly by the clamp.

Option number 3. schematically shown in FIG. 3 is similar to Option No. 1, but the outer diameter of the optical module 4 is 1.1 mm. The transverse dimensions of the cable are 2 mm by 3 mm, and weight - 6.6 kg / km. Such a cable contains from one to four freely laid optical fibers 5 with a diameter of 250 μm and has an operating temperature range of no worse than minus 40 ° C to plus 70 ° C. In this cable, the diameters of fiberglass 2 and optical module 4 have close values and wedge clamps can be used for its free suspension. In all three variants, aramid filaments 3 can be used to break the sheath when cutting the end of the cable.

Cables of Options No. 1 and No. 3 are used as distribution cables of the FTTH network and as subscriber connection cables (drop cables). The cable of Option No. 2 is used as a drop cable. Cables of all three options allow termination with standard optical connectors with installation directly on the cable, if in Options No. 1 and No. 3 they contain one fiber.

Claims (13)

1. A fiber-optic cable, coiled, the materials and construction of which allow its use in outdoor conditions, containing at least one optical fiber designed to transmit information, and a plastic sheath, characterized in that it contains one longitudinal rigid power element that prevents compression and bending, one optical module, covering all optical fibers of the cable, longitudinal flexible power elements that prevent stretching, in the form of at least one thread, does not contain metal or other current conducting components and has transverse dimensions, the limited size of 5 mm. 2. A fiber-optic cable coiled according to claim 1, characterized in that a fiberglass (a plastic bar reinforced with fiberglass) is used as a rigid power element. 3. A fiber-optic cable coiled according to claim 1, characterized in that an aramid bar (a plastic bar reinforced with aramid fibers) is used as a rigid power element. 4. A fiber-optic cable coiled according to claim 1, characterized in that at least one thread containing fiberglass (glass fiber) is used as flexible power elements. 5. A fiber-optic cable coiled according to claim 1, characterized in that at least one yarn containing aramid fibers (aramid yarn) is used as flexible power elements. 6. A fiber-optic cable coiled according to claim 1, characterized in that it comprises at least one water blocking thread. 7. A fiber-optic cable navivnogo according to claim 1, characterized in that as the optical fibers are applied bend-sensitive single mode telecommunication optical fibers. 8. A fiber-optic cable coiled according to claim 1, characterized in that a module with free laying of one or more optical fibers is used as an optical module. 9. A fiber-optic cable coiled according to claim 1, characterized in that a module with a tight coverage of one optical fiber by a sheath of a module is used as an optical module. 10. A fiber-optic cable coiled according to claim 1, characterized in that the plastic sheath consists of plastic that emits little smoke when heated, and does not contain halogens. 11. A fiber-optic cable navivnogo according to claim 1, characterized in that the rigid power element and the optical module are parallel and have a longitudinal touch line. 12. A fiber-optic cable coiled according to claim 1, characterized in that the optical module has a circular cross section, and the transverse dimension of the rigid power element along an axis perpendicular to the plane passing through the center lines of the optical module and the rigid power element is greater than or approximately equal to diameter of the optical module. 13. A fiber-optic cable coiled according to claim 1, characterized in that it has a cross section close to a rectangular one.

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