Flame-retardant optical cable structure and optical cable bundle

Abstract

The utility model provides a flame-retardant optical cable structure and an optical cable bundle, relates to the technical field of optical cables, and solves the technical problem of poor flame-retardant performance of optical cables. The flame-retardant optical cable structure of the device comprises a sheath, an optical fiber and a tearing groove, the optical fiber is located in the sheath, and the cross section of the sheath is rectangular; the tearing grooves are formed in one side or two opposite sides of the sheath, and in the tearing grooves in the two opposite sides of the sheath, the cross sections of the tearing grooves are rotationally symmetrical about the center line of the sheath; when the two sheaths are spliced, the tearing grooves located on the different sheaths are isolated from each other. When the optical cables are bundled into an optical cable bundle, the sheaths are mutually spliced, so that gaps among the optical cables can be effectively reduced, and the air content among the sheaths is reduced; the axially symmetrical tearing grooves in the sheath are changed into the rotationally symmetrical tearing grooves, so that on one hand, the air content of gaps of the tearing grooves can be further reduced, and on the other hand, the supporting effect of air accumulation between the tearing grooves on combustion is reduced; the flame-retardant optical cable structure has more excellent flame-retardant performance.

Description

Technical Field

[0001] This utility model relates to the field of optical cable technology, and in particular to a flame-retardant optical cable structure and optical cable bundle. Background Technology

[0002] In recent years, the demand for flame-retardant B1 optical cables in China has been gradually increasing. Indoor butterfly drop cables have become the most widely used optical cables for indoor cabling by domestic operators due to their small size, convenient wiring, low cost, and stable mechanical and environmental performance.

[0003] Currently, most butterfly-shaped optical cables in large quantities used in China have a flame-retardant rating of single-strand vertical combustion. Existing optical cables include a sheath, optical fibers within the sheath, and reinforcing members. Because the high flame-retardant LSZH sheath material primarily uses inorganic flame retardants such as aluminum hydroxide and magnesium hydroxide, with a filling ratio exceeding 50%, and because these inorganic flame retardants are relatively inert and do not easily form chemical bonds with metal materials such as steel wires, the pull-out force of high flame-retardant butterfly cables is generally lower than that of ordinary single-strand flame-retardant butterfly cables. This means that when the optical cable is subjected to external forces, the force is easily transmitted directly through the sheath to the optical fiber, which is detrimental to the fiber's lifespan. Using adhesive-coated reinforcing members can effectively solve the problem of steel wire pull-out force; that is, the reinforcing members can improve the tensile strength of the optical cable. Furthermore, the reinforcing members are mostly parallel single steel wires, and to ensure that the reinforcing members adhere to the inside of the sheath, a surface coating of adhesive is applied to the outside of the reinforcing members.

[0004] The applicant has discovered that the prior art has at least the following technical problems: on the one hand, the reinforcing member (mostly steel wire) itself has good thermal conductivity, the surface coating adhesive outside the reinforcing member has poor flame retardant properties, and the flammability of the surface coating adhesive is not conducive to improving the flame retardant performance of the optical cable.

[0005] On the other hand, because the national standard B1 flame retardant test requires optical cables with an outer diameter of 5mm or less to be installed in cable bundles, and the cable bundles must not be twisted, in the existing technology of optical cable bundles, see [reference needed] Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of optical cables forming optical cable bundles in the existing technology; the sheath 1' has a circular or elliptical outline, and a V-shaped tear groove 3' needs to be set on the sheath 1'. The function of the tear groove 3' is to allow construction personnel to easily tear the sheath from the tear groove 3' during construction and installation, and take out the optical fiber for splicing, thereby simplifying the installation and maintenance process; the above results in more gaps between the sheaths 1' of different optical cables, and the air in the gaps reduces the flame retardant performance of the optical cable. Utility Model Content

[0006] The purpose of this utility model is to provide a flame-retardant optical cable structure and optical cable bundle to solve the technical problem of poor flame-retardant performance of optical cables in the prior art; the various technical effects of the preferred technical solutions among the many technical solutions provided by this utility model are described in detail below.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] The flame-retardant optical cable structure provided by this utility model includes a sheath, optical fibers, and tear grooves, wherein:

[0009] The optical fiber is located inside the sheath, and the cross-section of the sheath is rectangular;

[0010] The tear groove is formed on one side or opposite sides of the sheath. The cross-section of the tear groove on opposite sides of the sheath is rotationally symmetrical about the center line of the sheath. When two sheaths are spliced ​​together, the tear grooves on different sheaths are isolated from each other.

[0011] Preferably, the inner diameter of the tear groove gradually decreases along the direction close to the optical fiber.

[0012] Preferably, the flame-retardant optical cable structure further includes a reinforcing member located inside the sheath and on opposite sides of the optical fiber, the reinforcing member being arranged parallel to the optical fiber.

[0013] Preferably, on one side of the optical fiber, there are two or more reinforcing members, all of which are parallel to each other and attached to each other. The reinforcing members include adhesive-coated reinforcing members and smooth reinforcing members, with only the outer surface of the adhesive-coated reinforcing members being coated with adhesive.

[0014] Preferably, on one side of the optical fiber, the number of the reinforcing members is one or more, and the reinforcing members are coated with an ETEF thin film layer.

[0015] Preferably, the cross-section of the ETEF film layer is a regular polygon or an irregular shape, or the ETEF film layer is a sleeve formed by connecting multiple protrusions.

[0016] Preferably, the flame-retardant optical cable structure further includes a reinforcing tube, wherein the reinforcing tube is sleeved outside the optical fiber, and the reinforcing tube and the optical fiber are arranged coaxially.

[0017] Preferably, the optical fiber is coated with a first ETEF coating, and the first ETEF coating is coated with a high-temperature resistant fiber paste layer, which is located inside the reinforcing tube.

[0018] Preferably, the reinforcing tube is coated with a second ETEF coating.

[0019] This utility model also provides an optical cable bundle, including multiple optical cables, the optical cables having the above-mentioned flame-retardant optical cable structure, all the optical cables being arranged in a matrix, and adjacent sheaths being fitted together.

[0020] Compared with the prior art, the flame-retardant optical cable structure and optical cable bundle provided by this utility model have the following beneficial effects: the sheath is changed from a circular outline to a rectangular outline. When the optical cable is bundled into an optical cable bundle, the sheaths are spliced ​​together, which can effectively reduce the gap between the optical cables and reduce the air content between the sheaths; and the axially symmetrical tear groove on the sheath is changed to a rotationally symmetrical tear groove, which can further reduce the air content in the tear groove gaps and reduce the air accumulation between the tear grooves from supporting combustion; the flame-retardant optical cable structure has superior flame-retardant performance. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of optical cables forming optical cable bundles in the existing technology; in the diagram, 1' is the sheath; 3' is the tear groove;

[0023] Figure 2 This is a schematic diagram of the flame-retardant optical cable structure of the optical cable bundle of this utility model using Embodiment 1;

[0024] Figure 3 This is a schematic diagram of another embodiment of the flame-retardant optical cable structure of the optical cable bundle of this utility model;

[0025] Figure 4 This is a comparison diagram of several reinforcement configurations in Embodiment 2 of the flame-retardant optical cable structure;

[0026] Figure 5 This is a schematic diagram of the structure of embodiment three of the flame-retardant optical cable;

[0027] Figure 6 This is a schematic diagram of the structure of embodiment four of the flame-retardant optical cable;

[0028] Figure 7 This is a structural schematic diagram of embodiment five of the flame-retardant optical cable structure.

[0029] In the figure: 1. Sheath; 2. Optical fiber; 3. Tear groove; 4. Reinforcing member; 41. Adhesive-coated reinforcing member; 42. Smooth reinforcing member; 5. ETEF thin film layer; 6. Reinforcing tube; 7. High-temperature resistant fiber paste layer; 8. Second ETEF coating; 9. First ETEF coating. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0031] In the description of this utility model, it should be understood that the terms "center," "length," "width," "height," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and "side," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0032] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" 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 of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0033] This utility model provides a flame-retardant optical cable structure and optical cable bundle, which has superior flame-retardant performance.

[0034] The following is combined with Figures 2-7 The technical solution provided by this utility model will be described in more detail below.

[0035] Example 1

[0036] See Figure 2 , Figure 3 , Figures 5-7 As shown, this utility model provides a flame-retardant optical cable structure, including a sheath 1, an optical fiber 2, and a tear groove 3, wherein: the optical fiber 2 is located inside the sheath 1, and the cross-section of the sheath 1 is rectangular; the tear groove 3 is formed on one side or opposite sides of the sheath 1, and when the tear groove 3 is formed on opposite sides of the sheath 1, the cross-section of the tear groove 3 on opposite sides of the sheath 1 is rotationally symmetric about the centerline of the sheath 1; see also Figure 2 and Figure 3As shown, when multiple optical cables are bundled into an optical cable bundle, two adjacent sheaths 1 are spliced ​​together, and the tear grooves 3 located on different sheaths 1 are isolated from each other.

[0037] In this embodiment, the cross-section of the tear groove 3 on both sides of the sheath 1 is a centrally symmetrical figure about the center line of the sheath 1.

[0038] The flame-retardant optical cable structure provided by this utility model changes the sheath 1 from a circular outline to a rectangular outline. When the optical cable is bundled into a bundle, the sheaths 1 are spliced ​​together, which can effectively reduce the gaps between the optical cables and reduce the air content between the sheaths 1. Furthermore, the axially symmetrical tear groove 3 on the sheath 1 is changed to a rotationally symmetrical tear groove 3, which can further reduce the air content in the gaps of the tear groove 3 and reduce the supporting effect of air accumulation between the tear grooves 3 on combustion. This flame-retardant optical cable structure has superior flame-retardant performance.

[0039] The flame-retardant optical cable structure provided by this utility model improves the flame-retardant performance of the optical cable by reducing the gaps between the optical cables when the optical cables are bundled into optical cable bundles.

[0040] As an optional implementation, see Figure 2 , Figure 3 , Figures 5-7 As shown, the inner diameter of the tear groove 3 gradually decreases along the direction close to the optical fiber 2, further reducing the gap between the optical cables.

[0041] As an optional implementation, see Figure 2 , Figure 3 , Figures 5-7 As shown, the flame-retardant optical cable structure also includes a reinforcing member 4, which is located inside the sheath 1 and on opposite sides of the optical fiber 2. The reinforcing member 4 is arranged parallel to the optical fiber 2.

[0042] The reinforcing member 4 can be coated steel wire with a specification of 0.42*0.45mm. The reinforcing member 4 can be phosphated steel wire, galvanized steel wire, copper-plated steel wire, stainless steel wire, etc. The elastic modulus of the steel wire is greater than or equal to 190Gpa. The diameter of the reinforcing member 4 should be 0.42±0.01mm. The double parallel steel wires can ensure the theoretical requirement of 200N for short-term and 100N for long-term tensile force of the optical cable.

[0043] Example 2

[0044] This embodiment is an improvement based on Embodiment 1. See [link / reference] Figure 2 , Figure 3 As shown, on one side of optical fiber 2, there are two or more reinforcing members 4. All reinforcing members 4 are parallel to each other and fit together. (See Figure 1) Figure 4 The reinforcing member 4 includes an adhesive-coated reinforcing member 41 and a smooth reinforcing member 41, with only the outer surface of the adhesive-coated reinforcing member 41 being coated with adhesive.

[0045] To ensure that the reinforcing member 4 adheres to the inside of the sheath 1, a surface coating adhesive is applied to the outside of the reinforcing member 4. However, the surface coating adhesive in the prior art is flammable and does not improve the flame-retardant performance of the optical cable.

[0046] The reinforcing member 4 can also be steel strand, with specifications of 7*0.16mm or 3*0.24mm, consisting of 7 single steel wires with a diameter of 0.16mm or 3 single steel wires with a diameter of 0.24mm, respectively. The modulus of a single steel wire is greater than 190Gpa, and the outer diameter of the stranded strand is 0.48mm and 0.52mm, respectively. Compared to single steel wires, the steel strand bonds more tightly to the sheath 1. The surface of the steel strand can be coated with adhesive or not, or one, two, or three steel wires can be coated with adhesive. This can further reduce the adverse effects of adhesive usage on the flame-retardant performance of the optical cable, while increasing the pull-out force of the optical cable reinforcing member 4.

[0047] See Figure 4 As shown, in this embodiment, by reducing the diameter of the reinforcing member 4 and increasing the number of reinforcing members 4, the structural strength is ensured. While meeting the theoretical tensile strength of the optical cable, the problem of insufficient pull-out force between the sheath 1 and the reinforcing member 4 can be effectively solved. Only one or part of the reinforcing members 4 are coated with a coating adhesive, which can improve the flame retardant performance by reducing the amount of coating adhesive used.

[0048] Example 3

[0049] This embodiment is an improvement based on Embodiment 1. See [link / reference] Figure 5 As shown, on one side of the optical fiber 2, there is one or more reinforcing members 4, and the reinforcing members 4 are coated with an ETEF thin film layer 5.

[0050] As an optional implementation, the cross-section of the ETEF thin film layer 5 is a regular polygon or an irregular shape.

[0051] The ETEF film layer 5, made of ETFE material, possesses excellent flame-retardant properties and strong adhesion to metals. The cross-section of the ETEF film layer 5 is a regular polygon or irregular shape, ensuring a tight bond between the sheath 1 and the ETFE film layer. Simultaneously, the ETFE film layer is tightly bonded to the reinforcing member 4, enabling the reinforcing member 4 to fully withstand external forces on the optical cable and protect the optical fiber 2 from external stress. The high flame-retardant properties of the ETFE film layer significantly mitigate the adverse effects of ordinary adhesive-coated reinforcing members on the flame-retardant performance of the optical cable. Furthermore, the high elastic modulus of ETFE material can improve the tensile strength of the optical cable to a certain extent.

[0052] Example 4

[0053] This embodiment is an improvement based on Embodiment 1. See [link / reference] Figure 6As shown, the difference between this embodiment and embodiment three is that the ETEF thin film layer 5 is a sleeve formed by connecting multiple protrusions.

[0054] This structure also improves the tight adhesion between the ETFE film layer 5 and the sheath 1, while ensuring that the ETFE film layer is tightly bonded to the reinforcing member 4, so that the reinforcing member 4 can fully withstand the external forces on the optical cable and protect the optical fiber 2 from external forces.

[0055] Example 5

[0056] This embodiment is an improvement based on Embodiment 1. See [link / reference] Figure 7 As shown, the flame-retardant optical cable structure also includes a reinforcing tube 6, wherein the reinforcing tube 6 is sleeved outside the optical fiber 2, and the reinforcing tube 6 and the optical fiber 2 are arranged coaxially.

[0057] The reinforcing tube 6 can be a stainless steel tube; in this embodiment, steel wire or the like is not used as the reinforcing element 4.

[0058] See Figure 7 In this embodiment, a stainless steel tube is used to cover the optical fiber 2. The outer diameter of the stainless steel tube is 1.0 mm and the wall thickness is 0.1 mm. Theoretically, it is equivalent to the tensile force provided by two 0.42 mm steel wires, which can meet the tensile force of 200 N in the short term and 100 N in the long term. At the same time, it improves the pressure resistance and anti-fire performance of the optical cable, and can isolate the burning flame from the optical fiber 2.

[0059] As an optional implementation, see Figure 7 The optical fiber 2 is coated with a first ETEF coating 9, and the first ETEF coating 9 is coated with a high-temperature resistant fiber paste layer 7, which is located inside the reinforcing tube 6. The reinforcing tube 6 is coated with a second ETEF coating 8.

[0060] A 0.4mm diameter ETFE-coated optical fiber 2 is placed inside the reinforcing tube 6 (stainless steel tube), and filled with a high-temperature resistant fiber paste layer 7 that can withstand temperatures up to 300℃. This paste layer contains a certain proportion of magnesium hydroxide, which decomposes at high temperatures, absorbing a large amount of heat and thus reducing the surface temperature of the burning material and slowing down the combustion rate. The reinforcing tube 6 is coated with a first ETFE coating, which has a fire resistance rating of B1 and is classified as a flame-retardant material. During combustion, the ETFE film will not drip, and the fire will not spread. Overall, it exhibits strong high-temperature resistance and fire resistance, meeting the requirements of GB / T19216.25, and maintaining normal communication for 90 minutes under flames exceeding 750℃.

[0061] See Figure 2 , Figure 3 and Figure 7In this embodiment, the sheath 1 does not have a reinforcing member 4 inside; only a reinforcing tube 6 is provided at the center, and two pairs of rotationally symmetrical narrow tear grooves 3 are provided on the four sides. The sheath 1 is square in shape, and the outer diameter can be 3.0*3.0mm or other sizes. Compared with common butterfly cables with parallel reinforcing members 4, this structure can ensure the consistency and stability of the bundled burning of the optical cable, reduce the impact of the uncertainty of the position of multiple optical cable reinforcing wires on the burning result, and reduce the gaps between optical cables. By rotating the tear grooves 3, the tear grooves 3 of the connected butterfly cables are staggered, further reducing the air accumulation between the tear grooves 3 and the support effect on combustion. The outer sheath 1 is made of high flame-retardant, low-smoke, halogen-free flame-retardant polyolefin with an oxygen index higher than 45%, ensuring that the flame retardant level of the optical cable meets the B1 level specified in GB 3127.

[0062] In this embodiment, a reinforcing tube 6 (stainless steel tube) is used instead of the glued steel wire reinforcing member 4 to improve the flame retardant performance of the optical cable.

[0063] Example 6

[0064] This embodiment is an improvement based on Embodiment 1. See [link / reference] Figure 2 and Figure 3 As shown, this embodiment provides an optical cable bundle, including multiple optical cables. The optical cables have the above-mentioned flame-retardant optical cable structure. All optical cables are arranged in a matrix, and adjacent sheaths 1 are bonded to each other.

[0065] The optical cable can be a butterfly cable or other types of optical cable. This embodiment uses a butterfly cable as an example. 4. Because the national standard B1 flame retardant test requires optical cables with an outer diameter less than or equal to 5mm to be installed in bundles, each bundle having a diameter of approximately 10mm, and the bundles must not be twisted. See [link / reference] Figures 1-3 As shown, the size of the butterfly cable can be changed from 3.0*2.0mm to 3.0*3.0mm, and the number of optical cables in the flame retardant test bundle can be reduced from 15 to 9. Figure 2 As shown, 15 optical cables are bundled together. (See attached image) Figure 3 As shown, the nine optical cables are bundled together, which increases the proportion of the flame-retardant sheath 1 and reduces the adverse effects of the non-flame-retardant components (adhesive layer) in the reinforcing member 4 on the flame-retardant test, thus effectively improving the flame-retardant test results of the butterfly cable B1.

[0066] The specific features, structures, or characteristics described in this specification may be combined in any suitable manner in one or more embodiments or examples.

[0067] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0068] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A flame-retardant optical cable structure, characterized by, The flame-retardant optical cable structure comprises a jacket, an optical fiber and a tear groove, wherein: the optical fiber is located in the jacket, and the jacket has a rectangular cross section; the tear groove is formed on one side or opposite sides of the jacket, and the cross section of the tear groove on the opposite sides of the jacket is a rotationally symmetric figure about the center line of the jacket; when two jackets are spliced, the tear grooves on the different jackets are isolated from each other.

2. The flame retardant optical cable structure of claim 1, wherein, The inner diameter of the tear groove gradually decreases in the direction close to the optical fiber.

3. The flame retardant optical cable structure of claim 1, wherein, The flame-retardant optical cable structure further comprises a reinforcing member, which is located in the jacket and on opposite sides of the optical fiber, and is arranged in parallel with the optical fiber.

4. The flame retardant optical cable structure of claim 3, wherein, On one side of the optical fiber, the number of the reinforcing members is two or more, all the reinforcing members are parallel to and in contact with each other, the reinforcing members comprise a coated reinforcing member and a smooth reinforcing member, and only the outer surface of the coated reinforcing member is coated with a coating glue.

5. The flame retardant optical cable structure of claim 3, wherein, On one side of the optical fiber, the number of the reinforcing members is one or two or more, and the reinforcing members are coated with an ETEF film layer.

6. The flame retardant optical cable structure of claim 5, wherein, The cross section of the ETEF film layer is a regular polygon or an irregular shape, or the ETEF film layer is a sleeve formed by connecting a plurality of convex parts.

7. The flame retardant optical cable structure of claim 1, wherein, The flame-retardant optical cable structure further comprises a reinforcing tube, wherein the reinforcing tube is sleeved on the optical fiber, and the reinforcing tube is coaxial with the optical fiber.

8. The flame retardant optical cable structure of claim 7, wherein, The optical fiber is coated with a first ETEF coating layer, the first ETEF coating layer is coated with a high-temperature-resistant fiber paste layer, and the high-temperature-resistant fiber paste layer is located in the reinforcing tube.

9. The flame retardant optical cable structure according to claim 7 or 8, characterized in that, The reinforcing tube is coated with a second ETEF coating layer.

10. An optical cable bundle characterized in that, The flame-retardant optical cable structure comprises a plurality of optical cables, each of which has the flame-retardant optical cable structure as claimed in any one of claims 1-9, all the optical cables are arranged in a matrix, and adjacent jackets are in contact with each other.

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