A lightweight flame-retardant sensing optical cable for rapid positioning

Abstract

The application belongs to the field of optical communication transmission technology, and discloses a light-weight fire-retardant sensing optical cable with rapid positioning, which comprises, from inside to outside, a sensing optical fiber, a water-blocking layer, a reinforcing element and a fire-retardant layer, and is provided with a self-adhesive layer on the side surface, wherein the sensing optical fiber is used for performing real-time sensing on external disturbances, the water-blocking layer is arranged on the outer periphery of the sensing optical fiber and plays a water-proof role, the reinforcing element is used for improving the mechanical properties of the whole sensing optical cable, the fire-retardant layer is arranged on the outermost layer of the sensing optical cable and plays a fire-retardant role, and the self-adhesive layer is used for attaching and installing the sensing optical cable on a target object. Through the application, the sensing optical cable can not only be installed in a non-underground laying mode in an efficient, reliable and convenient-to-control manner, but also has the advantages of high positioning accuracy, light weight, good fire resistance and the like, and greatly facilitates the later maintenance work, and is particularly suitable for application occasions such as accident positioning of highways and elevated roads.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of optical communication transmission technology, and more particularly, relates to a light-weight flame-retardant sensing optical cable with rapid positioning. BACKGROUND

[0002] As an important part of the national traffic road network, expressways, elevated roads and the like have a significant role in improving traffic efficiency, improving regional traffic conditions, and facilitating travel services. Such roads are more prone to traffic safety accidents due to their own road conditions, design, and fast driving speed. Therefore, in order to protect vehicles from falling sideways from the road when a vehicle collision or other safety accident occurs, guardrails are generally installed on both sides of such roads, mainly to absorb energy and also to provide good protection for vehicles and passengers. The requirements for such guardrails are generally not easily damaged, and need to increase certain aesthetic properties, and have characteristics such as corrosion resistance, anti-aging, and sun resistance.

[0003] Due to the widespread use of expressways, elevated roads, or other similar guardrails, the maintenance of the guardrails is therefore critical. Currently, the discovery of damage, collapse, and fracture of the guardrails is generally through video monitoring, dedicated patrols, and reports from concerned citizens, and it is difficult to achieve timely, efficient, and full-line coverage. Moreover, once a traffic accident such as a collision with a guardrail is discovered, it is difficult to accurately locate the accident site due to the lack of reference points, which further leads to difficulties in providing timely medical treatment for the injured and the dead, and therefore there is a need to provide alarm services for various types of road collision guardrail accidents.

[0004] In view of the above technical problems, the existing technology generally chooses to lay a vibration sensing optical cable under the guardrail to locate the position of the accident by monitoring the change in light intensity when a vehicle collides, or to determine the precise location by the point of signal disappearance if the guardrail collapses, fractures, or the like under the impact of a collision. However, further research has shown that the existing technology still has the following defects or deficiencies: first, since such optical cables are buried underground, the perception of vibration is not clear, and they are easily affected by the vibration interference caused by large vehicles driving at high speeds, which may result in insufficient positioning accuracy; second, such sensing optical cables need to be planned at the initial stage of road design, otherwise, if they need to be laid or maintained later, the road surface needs to be excavated, which seriously affects the smoothness of the road and causes great inconvenience for later maintenance.

[0005] Correspondingly, there is a need in the art to further improve it to better meet the comprehensive needs of various road positionings. SUMMARY

[0006] In response to one or more of the above-mentioned defects or needs in the prior art, the present invention provides a lightweight flame-retardant sensing optical cable with rapid positioning, in which the internal structure and setting method of the sensing optical cable are re-studied and designed, and targeted improvements are made to some key performance indicators and other aspects. This not only ensures that the sensing optical cable can be installed in a non-underground manner in an efficient, reliable and easy-to-control manner, but also has the advantages of high positioning accuracy, light weight, and good flame retardancy. At the same time, it greatly facilitates subsequent maintenance work, and is therefore particularly suitable for application scenarios such as accident positioning on highways and elevated roads.

[0007] To achieve the above object, according to the present invention, a fast-positioning lightweight flame-retardant sensing optical cable is provided, characterized in that the sensing optical cable comprises, from the inside to the outside, a sensing optical fiber, a water-blocking layer, a reinforcing element, and a flame-retardant layer, and a self-adhesive layer is provided on the side, wherein:

[0008] The sensing optical fiber is used to perform real-time sensing of external disturbances;

[0009] The water-blocking layer is arranged on the periphery of the sensing optical fiber and plays a waterproof role;

[0010] The reinforcing element is used to improve the mechanical properties of the entire sensing optical cable;

[0011] The flame retardant layer is arranged on the outermost layer of the sensor optical cable and plays a flame retardant role;

[0012] In addition, the above-mentioned sensing optical cable is attached and installed on the target object through the self-adhesive layer.

[0013] As a further preferred embodiment of the present invention, the sensing optical fiber may adopt a loose tube structure, wherein the optical fibers are centrally placed in the tube, and then a water-blocking tape is longitudinally wrapped on the outside of the tube and bound with water-blocking yarn.

[0014] As a further preferred embodiment of the present invention, the sensing optical fiber can be a tight-buffered optical fiber to further reduce the overall size of the sensing optical cable, wherein water-blocking yarn is placed parallel to the outside of the tight-buffered optical fiber or a water-blocking tape is used to longitudinally wrap it.

[0015] As a further preferred embodiment of the present invention, the reinforcing elements are made of fiber-reinforced composite materials and are arranged in parallel on both horizontal sides of the sensing optical fiber.

[0016] As a further preferred embodiment of the present invention, the performance index of the reinforcing element is designed as follows: the bending strength is above 900 MPa, and more preferably 1000 MPa to 1400 MPa.

[0017] As a further preferred embodiment of the present application, the main component of the flame-retardant layer is polyethylene, and a proper amount of flame retardant and other blending materials are added; wherein the polyethylene material is preferably cylindrical particles with a diameter of 3mm to 4mm and a height of 3mm to 6mm.

[0018] As a further preferred embodiment of the present application, the performance indicators of the flame-retardant layer are designed as follows: the tensile strength change rate is less than 30% after 1008H UV aging, and further preferably less than 25%; the elongation at break change rate is less than 25% after 1008H UV aging, and further preferably less than 20%.

[0019] As a further preferred embodiment of the present application, the main component of the self-adhesive layer is polyethylene, and 10% to 15% of polyester polyol and 4% to 8% of polybutene are added according to the weight percentage.

[0020] As a further preferred embodiment of the present application, the performance indicators of the self-adhesive layer are designed as follows: the thickness is greater than 20μm, and further preferably 20μm to 50μm; the width occupies more than 50% of the width of the area, and further preferably 100%.

[0021] As a further preferred embodiment of the present application, the sensing optical cable is preferably flat and has an elliptical cross-section, and the self-adhesive layer is arranged on one side of the non-circular arc area of the flat structure.

[0022] As a further preferred embodiment of the present application, the sensing optical cable is used for accident positioning monitoring of various roads.

[0023] Overall, compared with the prior art, the above technical solutions conceived by the present application mainly have the following technical advantages:

[0024] (1) The present application re-designs the internal structure and composition of the sensing optical cable and sets a self-adhesive layer on the side, which can not only ensure that the sensing optical fiber has appropriate flame-retardant, waterproof and structural strength properties, but also can be adhered to the target object such as the guardrail on both sides of the highway and elevated road in a high-efficiency, reliable and easy-to-control manner through the self-adhesive layer only, which not only greatly facilitates the pre-construction and post-maintenance, but also significantly improves the optical fiber sensing accuracy compared with the prior art, effectively avoiding the adverse effects of external interference factors;

[0025] (2) The present application also optimizes the material and key performance indicators of the reinforcing element, an important component: wherein the reinforcing element is made of FRP material and arranged in parallel on both sides of the sensing optical fiber, and the performance indicators of the bending strength are specifically limited, which not only ensures that the entire optical cable has the required mechanical properties, but also effectively prevents the guardrail from being damaged and exposing the optical cable inside after being severely impacted, causing secondary injury to the driver.

[0026] (3) The present application also optimizes the material and key performance indicators of the self-adhesive layer, an important component: by using a similar material to the flame-retardant layer as the base resin for the self-adhesive layer, adding appropriate other components, and making targeted limitations on the thickness and width, etc., sufficient adhesion and flexibility can be provided, and the sensing optical cable can be more closely attached to the guardrail, which helps to improve the response of the sensing optical cable to external disturbances;

[0027] (4) The present application also optimizes the specific types and mutual arrangement of the sensing optical fiber, the flame-retardant layer, and the water-blocking layer: the tightly sleeved optical fiber can further reduce the overall size of the sensing optical cable; the flame-retardant layer using polyethylene as the main component can be better arranged with the self-adhesive layer, and its performance indicators can ensure that it still provides sufficient tensile strength and a small elongation at break after long-term use and aging, thereby improving the reliability and environmental adaptability of the sensing optical cable;

[0028] (5) The sensing optical cable of the present application has a lightweight and compact overall structure, good flame retardancy, and high positioning accuracy, easy installation, and post-maintenance, etc., and is particularly suitable for accident positioning applications such as highways and elevated roads, and has good practical value and application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a structural cross-sectional view of a lightweight flame-retardant sensing optical cable according to a preferred embodiment of the present application;

[0030] In all the drawings, the same reference signs are used to represent the same elements or structures, specifically:

[0031] 1 - flame-retardant layer; 2 - sensing optical fiber; 3 - reinforcing element; 4 - water-blocking yarn; 5 - water-blocking yarn; 6 - self-adhesive layer. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0033] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0034] 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 the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0035] In the present invention, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0036] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0037] Figure 1 This is a cross-sectional view of the structure of a lightweight flame-retardant sensor optical cable according to a preferred embodiment of the present invention, which will be referred to below. Figure 1 The present invention will be explained in more detail.

[0038] See Figure 1The optical sensing cable of the present invention is, for example, flat as a whole and has an elliptical cross-section. It includes, from the inside to the outside, a sensing optical fiber 2, a water-blocking layer, a reinforcing element 3, and a flame-retardant layer 1, and a self-adhesive layer 6 is provided on the side, wherein the sensing optical fiber 2 is used to perform real-time sensing of external disturbances; the water-blocking layer is provided on the periphery of the sensing optical fiber and plays a waterproof role; the reinforcing element 3 is used to improve the mechanical properties of the entire sensing optical cable; the flame-retardant layer 1 is provided on the outermost layer of the sensing optical cable and plays a flame-retardant role; in addition, the above-mentioned optical sensing cable is adhered and installed on the target object through the self-adhesive layer 6.

[0039] Through the above conception, compared with the conventional laying methods of optical cables in the prior art, such as direct burial, pipeline, overhead, etc., the sensor optical cable is laid using a self-adhesive method. Compared with direct burial, the construction will not damage the original road surface, resulting in unnecessary costs; compared with the pipeline construction method, the transmission of vibration will be clearer and more specific, reducing the risk of unidentified; compared with the overhead construction method, the overhead laying is generally suspended between two fixed frames, and the distance between the two fixed frames should not be too long, otherwise the optical cable will be easily bent due to the influence of gravity, and the overhead method can only rely on the fixed frame to collect vibrations, and there is also a risk of not being able to fully collect signals. Therefore, the advantage of using the self-adhesive method is that the optical cable can fit the object to be monitored more closely and can clearly identify changes; and the self-adhesive method is simple to operate, can improve construction efficiency, and does not require additional costs. In addition, the flat-shaped optical cable preferably designed by the present invention can further increase the direct contact area between the optical cable and the monitored object such as the guardrail, improve the monitoring sensitivity, and enhance the signal collection capability.

[0040] Specifically, according to a preferred embodiment of the present invention, the sensing optical fiber 2 can adopt a loose tube structure, wherein the optical fibers are centrally placed in the tube. The sensing optical fiber can also adopt a tight tube structure, which can further reduce the overall size of the sensing optical cable. In addition, the number of sensing optical fibers is generally 1 to 12, preferably 2 to 6.

[0041] According to another preferred embodiment of the present invention, for the water-blocking layer, its main function is to prevent water penetration. The main component of optical fiber is silicon dioxide. When optical fiber is exposed to water, water molecules will gradually penetrate into the optical fiber surface and react with silicon atoms to hydrolyze, resulting in the rupture of silicon-oxygen bonds, thereby causing damage and cracks inside the optical fiber. When using a tight-buffered optical fiber, it is preferred to place a water-blocking yarn or use a water-blocking tape to wrap it longitudinally outside the optical fiber to strengthen the water-blocking performance of the optical cable; and when using a sensor optical cable with a loose tube structure, it is preferred to add a water-blocking yarn 4 or fill it with water-blocking powder in the loose tube, and place another water-blocking yarn 4 or use a water-blocking tape to wrap it longitudinally outside the tube, thereby reducing the impact of water on the performance of the sensing optical fiber.

[0042] According to another preferred embodiment of the present invention, the reinforcing elements are preferably designed as two parallel reinforcing elements on either side of the sensor unit to ensure the mechanical performance of the optical cable. The reinforcing elements are preferably made of FRP, which is composed of glass fiber and resin and has a bending strength requirement of ≥900 MPa, preferably 1000 MPa to 1400 MPa. This prevents severe impacts on the guardrail, which could damage the guardrail and expose the optical cable within, potentially causing secondary injury to the driver.

[0043] According to another preferred embodiment of the present invention, the flame-retardant layer is preferably a flame-retardant blended material whose primary component is polyethylene, with appropriate amounts of flame retardants and other modifying agents added, which is then mixed, plasticized, and granulated to produce the material. Considering that the sensor cable is laid on the guardrail in a self-adhesive manner, its performance indicators are preferably a change in tensile strength after 1008 hours of UV aging of ≤30%, more preferably ≤25%; and a change in elongation at break after 1008 hours of UV aging of ≤25%, more preferably ≤20%. Furthermore, the flame-retardant polyethylene material used is preferably cylindrical particles with a diameter of 3mm to 4mm and a height of 3mm or more, or other granular shapes of comparable size.

[0044] According to another preferred embodiment of the present invention, the main function of the self-adhesive layer is to enable the sensing optical cable to effectively adhere to the guardrail and play a sensing role. The self-adhesive layer used in the present invention mainly uses polyethylene as the base resin, and a certain amount of tackifier and plasticizer are added thereto to give the self-adhesive layer a certain adhesive force and flexibility. For example, the main component of the self-adhesive layer is polyethylene, and is added with 10% to 15% by weight of polyester polyol and 4% to 8% by weight of polybutene, wherein the molecular chain of polybutene is preferably ≤100000. In order to ensure that it can meet the use of various complex working conditions, the thickness of the self-adhesive layer of the sensing optical cable provided by the present invention is required to be ≥20um, and more preferably 30 to 50um; the width of the self-adhesive layer needs to occupy 50% to 100% of the width of the side of the setting, preferably 100%, in this way to ensure that the optical cable fits tightly to the guardrail and further improve the response of the sensing optical cable to external disturbances.

[0045] In order to better understand the products of the present invention, the following specific examples are provided.

[0046] Example 1:

[0047] In this embodiment, a loose tube structure optical fiber is used. There are two sensing optical fibers in the tube. The two optical fibers are different in color. The tube is also filled with a water-blocking yarn. A water-blocking tape is longitudinally wrapped around the outside of the tube and bound with water-blocking yarn. Two FRPs with a diameter of 1.6 mm are placed on both sides of the optical fiber. The outer layer uses a black flame-retardant sheath material, and a self-adhesive layer is attached to one side.

[0048] Embodiment 2

[0049] In this embodiment, a tight-fitting sensing optical fiber is used, a water-blocking tape is placed parallel to the outside of the optical fiber, and two FRPs with a diameter of 1.0 mm are placed on both sides of the optical fiber. A black flame-retardant sheath material is used for the outer layer, and a self-adhesive layer is attached to one side.

[0050] The working process of the sensing optical cable according to the present application will be briefly explained below.

[0051] When the sensing optical cable is subjected to external force or abnormal vibration, the transmitted light wave signal will be disturbed. The main controller monitors the fluctuation of the electrical signal converted from the variation of the light wave signal, and converts the electrical signal into a digital signal through the main controller. After processing the received signal, the point of signal abnormality on the line can be accurately located, and the accident point can be quickly located.

[0052] In summary, the sensing optical cable according to the present application is re-designed by studying its internal structure and setting method, and some key performance indicators are improved. The sensing optical cable not only ensures efficient and reliable installation of non-underground buried type, but also has the advantages of high positioning accuracy, light weight, good flame retardancy, etc. It greatly facilitates the maintenance work in the later stage, and is especially suitable for applications such as accident positioning of highways and elevated roads, and has good practical value and application prospect.

[0053] Those skilled in the art will readily understand that the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A fast-positioning, lightweight, flame-retardant sensor optical cable, characterized in that: The sensing optical cable comprises a sensing optical fiber, a water-blocking layer, a strengthening element and a flame-retardant layer from the inside to the outside, and a self-adhesive layer is provided on the side, wherein: The sensing optical fiber is used to perform real-time sensing of external disturbances; The water-blocking layer is arranged on the periphery of the sensing optical fiber and plays a waterproof role; The reinforcing element is used to improve the mechanical properties of the entire sensing optical cable; The flame retardant layer is arranged on the outermost layer of the sensor optical cable and plays a flame retardant role; the main component of the flame retardant layer is polyethylene, and an appropriate amount of flame retardant and other blending materials are added; In addition, the above-mentioned sensing optical cable is attached to the target object through the self-adhesive layer; wherein the main component of the self-adhesive layer is polyethylene, and polyester polyol is added in an amount of 10% to 15% by weight, and polybutylene is added in an amount of 4% to 8% by weight.

2. The lightweight flame-retardant sensor optical cable according to claim 1, characterized in that: The sensing optical fiber adopts a loose tube structure, wherein the optical fibers are centrally placed in the tube, and then a water-blocking tape is longitudinally wrapped on the outside of the tube and bound with water-blocking yarn.

3. The lightweight flame-retardant sensor optical cable according to claim 1, characterized in that: The sensing optical fiber adopts a tight-buffered optical fiber to further reduce the overall size of the sensing optical cable, wherein a water-blocking yarn is placed parallel to the outside of the tight-buffered optical fiber, or a water-blocking tape is used to longitudinally wrap it.

4. The lightweight flame-retardant sensor optical cable according to any one of claims 1 to 3, characterized in that: The reinforcing elements are made of fiber-reinforced composite materials and are arranged in parallel on both horizontal sides of the sensing optical fiber.

5. The lightweight flame-retardant sensor optical cable according to claim 4, characterized in that: The performance index of the reinforcing element is designed as follows: the bending strength is above 900 MPa.

6. The lightweight flame-retardant sensor optical cable according to claim 5, characterized in that: The bending strength of the reinforcing element is 1000Mpa to 1400Mpa.

7. The lightweight flame-retardant sensor optical cable according to claim 4, characterized in that: The performance indicators of the flame retardant layer are designed as follows: after 1008H UV aging, the change rate of tensile strength is less than 30%, and the change rate of elongation at break is less than 25%.

8. The lightweight flame-retardant sensor optical cable according to claim 7, characterized in that: The performance indicators of the flame retardant layer are designed as follows: after 1008H UV aging, the change rate of tensile strength is less than 25%, and the change rate of elongation at break is less than 20%.

9. The lightweight flame-retardant sensor optical cable according to claim 4, characterized in that: The performance indicators of the self-adhesive layer are designed as follows: the thickness is 20 μm to 50 μm, and the width occupies 50% to 100% of the width of the area where it is located.

10. The lightweight flame-retardant sensor optical cable according to claim 4, characterized in that: The above-mentioned sensing optical cable is flat and has an elliptical cross-section, wherein the self-adhesive layer is arranged on one side of the non-arc region of the elliptical cross-section structure.

11. The lightweight flame-retardant sensor optical cable according to any one of claims 1 to 3, characterized in that: The above-mentioned optical sensor cables are used for accident location monitoring on various types of roads.

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