An aerial optical cable

Abstract

The application belongs to the field of optical cables, and particularly relates to an overhead optical cable, the outer layer of which is a sheath, which is composed of a bearing part and a body, a metal reinforcing part is arranged at the axial center of the bearing part, the cross section of the body is in a U shape, the bearing part is arranged at the middle part of the upper end of the body, an accommodating cavity is arranged in the body, the accommodating cavity is filled with SAP material, an oval cavity is arranged at the lower end of the accommodating cavity, an optical unit is arranged in the cavity, grooves are symmetrically arranged at the upper end of the body and the two sides of the bearing part, holes are arranged in the grooves, the holes are communicated with the accommodating cavity, and a conductive unit is embedded between the accommodating cavity and the cavity and close to the middle and lower end of the body. Through the specific structure, the tensile and torsional properties of the optical cable can be effectively improved, the tension and swing amplitude of the optical cable under wind force can be reduced, the stability of the optical cable can be improved, and the discharge or lightning strike risk of the optical cable can be reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of cable, in particular to an aerial optical cable. BACKGROUND

[0002] The optical cable is a cable for transmitting optical signals, and its laying methods include aerial, direct burial, pipe, underwater, etc.

[0003] The direct burial optical cable is armored with steel belts or wires and directly buried underground, requiring the performance of resisting external mechanical damage and the performance of preventing soil corrosion. The pipe optical cable is generally used in urban areas and generally does not need to be armored. The underwater optical cable has a much worse laying environment than the pipe and direct burial laying, and must adopt a structure armored with steel wires or belts. The aerial optical cable is used for hanging on the electric pole, and is generally used for long-distance secondary or secondary lines, and is suitable for special network optical cable lines or some local special sections.

[0004] In the west and north of China, the terrain and environment are complex, and the optical cable is generally laid in an aerial manner, but the aerial optical cable is vulnerable to natural disasters such as typhoon, and in seasons with strong wind, the aerial optical cable is often pulled and twisted, resulting in communication interruption, so the failure rate of the aerial optical cable is higher than that of the direct burial and pipe laying optical cable. The existing improvement method is to also increase the metal reinforcing member and other anti-pulling elements in the aerial optical cable, but the setting of too many metal reinforcing members increases the weight of the optical cable, increases the erection difficulty and cost, and when the metal reinforcing members are set less, the anti-pulling strength may not reach the expected effect. In addition, the setting of the metal reinforcing member also increases the risk of lightning strike. SUMMARY

[0005] In order to solve the problems that the existing aerial optical cable is weak in anti-pulling and anti-twisting performance under the influence of natural disasters such as typhoon, the erection difficulty and cost are increased after the metal reinforcing member is set, or the anti-pulling effect is still not as expected, and the risk of lightning strike is also increased, the present application provides an aerial optical cable.

[0006] The present application aims to:

[0007] I. improve the anti-pulling and anti-twisting performance of the aerial optical cable;

[0008] II. reduce the swing amplitude of the optical cable under the action of wind and rain, and improve the stability of the optical cable;

[0009] III. reduce the discharge or lightning strike risk of the aerial optical cable, and improve the service life of the optical cable.

[0010] In order to achieve the above-mentioned purposes, the present application adopts the following technical solutions.

[0011] An aerial optical cable, an outer layer is a sheath, which is composed of a bearing part and a body, the bearing part is provided with a metal reinforcing member at the axial center, the body is in U-shaped cross section, the bearing part is arranged in the middle of the upper end of the body, the body is internally provided with a containing cavity, the containing cavity is filled with SAP material, the lower end of the containing cavity is provided with an elliptical cavity, the long axis of the cavity is in the vertical direction, the cavity is provided with an optical unit, the upper end of the body and both sides of the bearing part are symmetrically provided with a groove, the groove is provided with a hole, the hole is communicated with the containing cavity, and a conductive unit is embedded between the containing cavity and the cavity and close to the middle and lower end of the body.

[0012] As a preferred,

[0013] The optical unit is formed by bundling single or multiple bundle tubes, and single or multiple optical fibers are arranged in the bundle tubes, and the outer wall of the optical unit abuts against the short axis of the elliptical cavity.

[0014] The conductive unit comprises, from inside to outside, a metal conductor, an insulating layer, a shielding layer, an inner sheath and a moisture-proof layer.

[0015] As a preferred,

[0016] The conductive unit is semi-embedded in the body.

[0017] As a preferred,

[0018] The main component of the SAP material is sodium polyacrylate, which is subjected to pre-water absorption treatment, and the pre-water absorption ratio is controlled to be 20-25 times.

[0019] As a preferred,

[0020] A degradable film layer is attached to the inner wall of the containing cavity.

[0021] As a preferred,

[0022] The hole is uniformly and spacedly arranged along the axial direction of the optical cable.

[0023] As a preferred,

[0024] A capillary tube is arranged in the hole.

[0025] As a preferred,

[0026] An isolation layer is arranged on the outer side of the metal reinforcing member, the isolation layer comprises a straight part and a cladding part, the cladding part is cladded on the outer side of the metal reinforcing member, and the straight part is symmetrically arranged above and below the cladding part, extends upward to the outer side of the sheath of the bearing part, and extends downward to the sheath of the body.

[0027] As a preferred,

[0028] A metal film is sprayed on the joint of the isolation layer and the sheath of the bearing part, and the thickness of the metal film is 5-10 μm.

[0029] As preferred,

[0030] The metal film is a copper-zinc aluminum oxide composite, the thickness ratio of copper-zinc aluminum oxide is 7:3, and the doping amount of aluminum in zinc aluminum oxide is 0.5-2wt%.

[0031] The beneficial effects of the present application are:

[0032] The present application improves the tensile and torsional properties of the optical cable by cooperating the metal reinforcing member with the conductive unit; at the same time, the conductive unit adopts a semi-enclosed structure combined with the special shape of the optical cable body, which is easy to form a "sinking" effect under the action of wind, which can effectively reduce the tension of the metal reinforcing member; in windy or rainy weather, the optical cable is easy to accumulate static electricity, which can cause the optical cable to discharge and reduce the service life of the optical cable, the metal film is arranged in the bearing part, which can timely guide the charge in the optical cable out, reducing the discharge or lightning risk of the overhead optical cable; in addition, the accommodating cavity of the body is filled with SAP material, in rainy weather with strong wind, water vapor will penetrate into the accommodating cavity through the hole, the SAP material absorbs water and expands, increasing the weight of the optical cable, which can also reduce the swing amplitude of the optical cable under the action of wind. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the present application;

[0034] Figure 2 It is a schematic diagram of the hole along the axial direction of the optical cable of the present application;

[0035] Figure 3 It is a schematic diagram of the present application under the action of wind;

[0036] In the figure: bearing part 1, body 2, sheath 3, metal reinforcing member 4, accommodating cavity 5, SAP material 6, cavity 7, optical unit 8, groove 9, hole 10, conductive unit 11, degradable film layer 12, capillary tube 13, isolation layer 14, straight part 141, cladding part 142, metal film 15. DETAILED DESCRIPTION

[0037] The present application will be further described and illustrated in detail below in combination with specific embodiments and the accompanying drawings. Based on these descriptions, those skilled in the art will be able to implement the present application. In addition, the embodiments of the present application involved in the following description are generally only a part of the embodiments of the present application, not all the embodiments. Therefore, based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor shall fall within the scope of protection of the present application.

[0038] In the description of the application, it is to be understood that the terms "thickness", "upper", "lower", "horizontal", "top", "bottom", "inner", "outer", "circumferential" and the like are used as indicative of the orientation or positional relationship as shown in the drawings, and are merely intended to facilitate the description of the application and simplify the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In the description of the application, the meaning of "a plurality of" is at least two, such as two, three, etc., and the meaning of "several" is one or more, unless otherwise explicitly specified and limited.

[0039] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected or communicate with each other; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0040] Unless otherwise specified, the raw materials used in the embodiments of the present application are commercially available or can be obtained by those skilled in the art. Unless otherwise specified, the methods used in the embodiments of the present application are methods mastered by those skilled in the art.

[0041] Embodiment

[0042] A kind of as Figure 1The shown overhead optical cable is composed of a load bearing part 1 at the upper end and a body 2, the cross section of the body is U-shaped, the load bearing part is arranged at the middle of the upper end of the body, the outermost layer of the load bearing part and the body is a sheath 3, in actual manufacture, the outer sheath of the load bearing part and the body is integrally formed by the same extruding machine, the load bearing part is provided with a metal reinforcing member 4 at the axis, the metal reinforcing member plays a supporting role for the whole optical cable, in the embodiment, the metal reinforcing member is a steel strand, the body is provided with a containing cavity 5, the containing cavity is filled with SAP (high molecular water absorbing resin) material 6, the main component of which is low cross-linking type polyacrylic sodium, in the embodiment, the SAP material of Japan Sumitomo-60S type is used, the water absorption ratio of which to pure water is about 260, the water absorption ratio to 0.9% physiological saline is about 100, and the water absorption ratio to rainwater is only about 50 (the water absorption ratio of commercially available SAP material to pure water is quite different, but the water absorption ratio to tap water or water with more impurities is basically close), the lower end of the containing cavity is provided with an oval cavity 7, the oval cavity is arranged in an up-down structure, i.e. the long axis is along the vertical direction, the cavity is provided with an optical unit 8, the optical unit is formed by bundling single or multiple bundles, single or multiple optical fibers are arranged in the bundle, the bundle is filled with water blocking material, and the outer wall of the optical unit is in abutment with the short axis of the oval cavity.

[0043] As shown in Figure 1 , 2 , the upper end of the body and the two sides of the load bearing part are symmetrically provided with grooves 9, the grooves are provided with hole channels 10, the hole channels are uniformly and spacedly arranged along the axial direction of the optical cable, the hole channels are arranged as single column or multiple columns according to the requirement, in the embodiment, the hole channels are multiple columns, the hole channels are through the containing cavity, and the containing cavity and the cavity are embedded with a conductive unit 11 near the middle and lower end of the body, the conductive unit is sequentially composed of a metal conductor, an insulation layer, a shielding layer, an inner sheath and a moisture-proof layer from inside to outside, in the embodiment, the metal conductor is copper material.

[0044] The conductive unit is arranged at the middle and lower end of the body, the strength and toughness of the conductive unit is higher, when the optical cable is erected, the conductive unit can play a role of "lifting" the optical cable, and cooperates with the metal reinforcing member to support the optical cable, so that the tensile and torsional resistance of the optical cable is higher.

[0045] Further, the conductive unit is semi-embedded in the body, i.e. the circular arc surface of the conductive unit is higher than the U-shaped arc surface of the body. As shown in Figure 3 , when the wind is relatively large, the optical cable is taken as an example of being subjected to the right side wind (F arrow), the wind blows to a and b arrow directions respectively after meeting the conductive unit, due to the higher circular arc surface of the conductive unit, the arrangement near the lower end and the smaller cross section of the lower end of the body, the wind force will quickly flow through the lower end of the body (b arrow), so that the pressure at the lower end of the optical cable is smaller than that at the upper end, the optical cable has a "downward" trend (c arrow), so that the gravity center moves downward, which is helpful to reduce the swing amplitude of the optical cable under the action of the wind.

[0046] When encountering strong wind accompanied by rain (or higher humidity) weather, the groove at the upper end of the body helps to receive rainwater and penetrate downward through the channel until it is absorbed by the SAP material in the containing cavity. The SAP material has strong water absorption capacity, which will increase the weight of the optical cable and lower the center of gravity, reducing the swing amplitude of the optical cable. At this time, the weighted SAP material will press the oval cavity downward, the long axis of the cavity becomes shorter and the short axis becomes longer, the two ends of the optical unit are separated from the short axis of the cavity, and the optical unit is not pressed, and the optical fiber is not easily damaged.

[0047] The dry SAP material has very strong water absorption capacity. To avoid the deformation of the optical cable caused by the rapid expansion of SAP after absorbing water, the SAP needs to be pre-imbibed. The pre-imbibed ratio is controlled at 20-25 times, and then the pre-imbibed SAP material is filled into the containing cavity during cabling.

[0048] When the optical cable is just erected, the support of the metal reinforcing member and the conductive unit is the strongest. With the passage of time, its support will weaken, and the sag of the optical cable will increase. Under the action of wind force, the swing amplitude of the optical cable will increase compared to when it is just erected. The idea of the present application is to continue to slowly absorb water and expand the SAP to moderately increase the weight of the optical cable, that is, at the initial stage of the erection of the optical cable, the SAP does not need to play the effect of water absorption. Based on this, a degradable film layer 12 is attached to the inner wall of the containing cavity. In this embodiment, the main component of the degradable film layer is polylactic acid (PLA). The degradable film layer initially plays a role of covering and isolating the pre-imbibed SAP material. With the passage of time, under the action of water or air or both, the degradable film layer gradually decomposes. The water in the channel slowly penetrates into the SAP material, and the SAP material continues to slowly absorb water and gradually increases the weight of the optical cable until the SAP material is saturated. To speed up the water penetration rate, a capillary tube 13 can be provided in the channel.

[0049] In windy or thunderstorm weather, the optical cable is twisted, the internal parts rub against each other to generate static electricity, and induced charges are also easily generated around the metal reinforcing member. The accumulation of charges easily leads to discharge of the optical cable, causing damage to the surrounding cables and reducing the service life of the optical cable. Therefore, an isolation layer 14 is further provided on the outside of the metal reinforcing member. The isolation layer is made of thermal insulation material, which is FRP in this embodiment. The isolation layer includes a straight portion 141 and a cladding portion 142. The cladding portion is wrapped around the outside of the metal reinforcing member, and the straight portion is symmetrically arranged above and below the cladding portion. The straight portion extends upward to the outside of the sheath of the load-bearing portion and is flush with the outer wall of the sheath of the load-bearing portion. The straight portion extends downward to the sheath of the body and penetrates the sheath of the body by 1-3 mm. A metal film 15 is sprayed on the junction of the isolation layer and the sheath. The thickness of the metal film is 5-10 μm. The metal film is a copper-zinc-aluminum oxide composite. The thickness ratio of copper to zinc-aluminum oxide is 7:3. The doping amount of aluminum in zinc-aluminum oxide is 0.5-2 wt%. Copper is easily oxidized in air, so an aluminum-containing zinc-aluminum oxide with an aluminum content of 0.5-2 wt% is deposited on the surface of the copper. The aluminum-containing zinc-aluminum oxide with an aluminum content of 0.5-2 wt% has good electrical conductivity, which not only ensures the conduction of the internal charges of the optical cable but also protects the copper. The thickness of the metal film is controlled to be 5-10 μm. The conductive charge conduction capacity of the metal film with a thin thickness will be poor after oxidation. When the thickness is too large, the sheath is easily cracked due to stress. When the optical cable is erected, the shielding layer of the conductive unit is grounded, which can reduce the accumulation of charges in the body of the optical cable. Since the metal film extends downward to the sheath of the body, the excess charges in the body can also be discharged to the air through the upper end of the metal film.

[0050] When the optical cable is deformed and rubbed or when induced charges or static charges are generated around the metal reinforcing member due to lightning, the charges are transmitted to the metal film through the thin isolation layer and then conducted to the air through the metal film, thereby avoiding the accumulation of charges in the optical cable. Even if the isolation film is broken due to lightning or charges, since the isolation layer is made of thermal insulation material, heat is not easily conducted to the metal reinforcing member and the body of the optical cable, and the communication function of the optical cable is not affected.

[0051] To prevent the SAP material in the accommodation cavity from leaking out, the accommodation cavities can be arranged at intervals along the axis of the optical cable. Identification bands are arranged on the sheaths corresponding to the adjacent two accommodation cavities to facilitate the erection and cutting of the optical cable. The optical cable can also be prevented from leaking SAP material by plugging the two sides of the optical cable with a plug.

Claims

1. An aerial optical cable, the outer layer of which is a sheath, consisting of a load-bearing part and a body, the load-bearing part being provided with a metal reinforcement in the axial center, characterized in that, The body section is U-shaped, the bearing part is arranged in the middle of the upper end of the body, the body is internally provided with a containing cavity, the containing cavity is filled with SAP material, the lower end of the containing cavity is provided with an oval cavity, the long axis of the cavity is in the vertical direction, the cavity is provided with a light unit, the upper end of the body is symmetrically provided with a groove on both sides of the bearing part, the groove is provided with a hole, the hole is in communication with the containing cavity, and a conductive unit is embedded between the containing cavity and the cavity and close to the middle and lower end of the body.

2. The overhead optical cable according to claim 1, characterized in that, the light unit is formed by bundling a single bundle tube or multiple bundle tubes, and a single or multiple optical fibers are arranged in the bundle tube, and the outer wall of the light unit abuts against the short axis of the oval cavity; the conductive unit comprises, from the inside to the outside, a metal conductor, an insulating layer, a shielding layer, an inner sheath, and a moisture-proof layer.

3. The overhead optical cable according to claim 1, characterized in that, the conductive unit is partially wrapped in the body.

4. The overhead optical cable according to claim 1, characterized in that, the main component of the SAP material is sodium polyacrylate, which is subjected to pre-water absorption treatment, and the pre-water absorption ratio is controlled to be 20-25 times.

5. The overhead optical cable according to claim 4, characterized in that, a degradable film layer is arranged on the inner wall of the containing cavity.

6. The overhead optical cable according to claim 1, characterized in that, the holes are uniformly and spacedly arranged along the axial direction of the optical cable.

7. The overhead optical cable according to claim 6, characterized in that, a capillary tube is arranged in the hole.

8. The overhead optical cable according to claim 1, characterized in that, an isolation layer is arranged on the outer side of the metal reinforcing member, the isolation layer comprises a straight portion and a cladding portion, the cladding portion is wrapped on the outer side of the metal reinforcing member, and the straight portion is symmetrically arranged above and below the cladding portion, extends upward to the outer side of the sheath of the bearing part, and extends downward to penetrate into the sheath of the body.

9. The overhead optical cable according to claim 8, characterized in that, a metal film is sprayed on the joint between the isolation layer and the sheath of the bearing part, and the thickness of the metal film is 5-10 µm.

10. The overhead optical cable according to claim 9, characterized in that, the metal film is a copper-zinc oxide aluminum composite, the thickness ratio of copper-zinc oxide aluminum is 7:3, and the doping amount of aluminum in zinc oxide aluminum is 0.5-2 wt%.

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