Temperature sensing optical cable based on fiber grating array

Abstract

The utility model relates to a temperature sensing optical cable based on a fiber bragg grating array, comprising a fiber bragg grating array, a hollow tube and a sheath, the fiber bragg grating array is packaged in the hollow tube in a spiral shape, and the hollow tube is filled with a heat conduction material. A plurality of gratings are evenly distributed on the fiber grating array at intervals in the length direction, hole positions are formed in the corresponding hollow pipes according to the point positions of the gratings, the hollow pipes are wrapped with aramid fibers in a winding mode, and the hollow pipes are sleeved with the protective sleeves. The temperature sensing optical cable based on the fiber grating array is high in temperature response speed and high in real-time performance; the influence of external stress can be isolated, and grating positioning can be realized.

Description

Technical field:

[0001] The utility model relates to the technical field of optical fiber cables, in particular to a temperature sensing optical cable based on an optical fiber grating array. Background technology:

[0002] With the continuous development of optical fiber technology, fiber Bragg grating sensors have been widely used in monitoring due to their advantages such as high precision, intrinsic safety, and anti-electromagnetic interference. At the same time, due to the limitations of point sensing, fiber Bragg grating array sensing technology has been developed. This technology etches a large number of fiber Bragg gratings on one optical fiber to achieve quasi-distributed optical fiber sensing monitoring. This technology is widely used in pipeline leakage, large-scale building structure monitoring, etc. in response to the development strategy of national water conservancy project modernization.

[0003] The fiber optic temperature sensing cable based on fiber grating array can not only use the entire cable as a temperature sensor, but also as a signal transmission medium. By laying the optical cable at different locations of the monitored structure, the temperature field of the structure can be obtained, and the life cycle management of the structure and the prediction of the future structure model can be realized.

[0004] Traditional temperature measurement optical cables encapsulate optical fibers in stainless steel spiral tubes, which are then protected by Kevlar and polyethylene sheaths. However, fiber grating arrays are susceptible to stress, and when traditional temperature measurement optical cables are used to monitor temperature outdoors, they will cause errors in temperature measurement results due to external stress. To ensure the strength of the optical cable, high-strength materials are used for wrapping and protection, which can easily affect the temperature response time of the optical cable, resulting in a lag in temperature monitoring and early warning. In addition, the positioning of the grating sensing points in the fiber grating array cannot be achieved. Utility model content:

[0005] The technical problem to be solved by the utility model is to provide a temperature sensing optical cable based on a fiber grating array. The temperature sensing optical cable based on the fiber grating array has a fast temperature response rate and high real-time performance; it can isolate the influence of external stress and realize grating positioning.

[0006] The technical solution of the utility model is to provide a temperature sensing optical cable based on a fiber grating array, comprising a fiber grating array, a hollow tube and a sheath, wherein the fiber grating array is longer than the length of the hollow tube and is spirally packaged inside the hollow tube, the two ends of the fiber grating array are respectively flush with the two ends of the hollow tube, the hollow tube is also filled with a heat-conducting material, a plurality of gratings are evenly spaced along the length direction of the fiber grating array, and holes are opened on the corresponding hollow tube according to the point positions of each grating, the outside of the hollow tube is wrapped with aramid fiber, and the sheath is arranged outside the hollow tube, wherein the hollow tube is a metal tube, and the sheath is an anti-ultraviolet sheath.

[0007] In the utility model, a fiber grating array with a grating interval of 1 meter is spirally packaged inside a hollow tube, and a fiber grating array of 1005 meters is evenly packaged in a 1 km optical cable, and the redundancy of the fiber grating array per kilometer is 5 meters, thereby isolating the influence of external stress on the fiber grating array inside the optical cable. Among them, the fiber grating array refers to etching several gratings on an optical fiber, each grating is a sensing point, and there is a certain spacing between the gratings.

[0008] Furthermore, the spacing between the gratings of the fiber grating array is equal, which is 1 meter. Correspondingly, two adjacent holes on the hollow tube are staggered on both sides of the hollow tube, and the spacing between them is 0.995 meters.

[0009] Preferably, the hollow tube is processed using metal with good thermal conductivity, such as stainless steel, to ensure rapid temperature response.

[0010] Preferably, according to the packaging ratio of the fiber grating array, holes are staggered on the upper and lower sides of the hollow tube with an interval of 0.995 meters. At the same time, the first grating point is aligned with the first hole, which not only increases the temperature response rate but also realizes the point positioning of the fiber grating in the array.

[0011] Preferably, the interior of the hollow tube is filled with a heat-conducting material such as thermal grease to help conduct temperature and reduce the temperature response time.

[0012] Preferably, the outer side of the hollow tube is wrapped with four strands of aramid fibers, which improves the strength of the optical cable and achieves tensile and compressive strengths of up to 400N.

[0013] Preferably, the sheath is a polyvinyl chloride sheath, and the outermost sheath is made of UV-proof material, which is suitable for long-term outdoor monitoring. The UV-proof material can be polyvinyl chloride.

[0014] Compared with the prior art, the present invention has the following advantages after adopting the above scheme:

[0015] 1. Fast temperature response rate and high real-time performance: The two sides of the hollow tube are perforated at the intervals of the corresponding gratings, and the interior is filled with thermal conductive materials, which reduces the temperature conduction hysteresis caused by the optical cable packaging structure, improves the temperature response rate, and realizes real-time monitoring;

[0016] 2. Isolation from external stress: The fiber grating array is packaged in a spiral shape, and there is a 5-meter fiber grating array (optical fiber with grating etched) redundancy for every kilometer of optical cable, ensuring that the optical cable is not affected by external stress;

[0017] 3. Realize grating positioning: According to the redundancy ratio of the fiber grating array, the interval between the holes on both sides of the hollow tube is 0.995 meters. The first grating point is aligned with the first hole, which can realize the point positioning of the fiber grating array;

[0018] 4. The optical cable has high strength and strong tensile strength: it uses aramid fiber and UV-proof sheath as the protective structure, which is suitable for long-term monitoring of large outdoor building structures. Description of the drawings:

[0019] Figure 1 This is a cross-sectional diagram of an optical fiber temperature sensing cable based on a fiber grating array;

[0020] Figure 2 This is a cross-sectional diagram of the optical fiber temperature sensing cable based on fiber grating array. Specific implementation method:

[0021] The present invention will be further described below with reference to the accompanying drawings:

[0022] The utility model discloses an optical fiber temperature measurement sensor cable based on a fiber grating array. Figure 1 As shown, it includes a fiber grating array 1, a hollow tube 2, a sheath 3 and an aramid fiber 4; wherein the hollow tube is a stainless steel tube, and the sheath is made of polyvinyl chloride material.

[0023] like Figure 2 As shown, in this embodiment, holes are punched up and down on both sides of the hollow tube 2 at a spacing of 0.995 meters, and then the fiber grating array 1 with a grating uniformly spaced 1 meter is spirally packaged inside the hollow tube 2, and 1005 meters of the fiber grating array 1 are uniformly packaged per kilometer of optical cable. The 5-meter optical fiber redundancy ensures that the optical cable is isolated from the influence of external stress during outdoor real-time monitoring; at the same time, the first grating point is aligned with the first hole position to achieve the point positioning of the fiber grating array 1; and then the inside of the hollow tube 2 is filled with thermal conductive silicone grease to increase the temperature response rate.

[0024] The outer side of the hollow tube 2 is protected by four strands of aramid fibers 4, and the tensile and compressive strength can reach 400N, which increases the strength of the optical cable; the outermost side is protected by an anti-ultraviolet sheath 3, which is suitable for long-term monitoring of large outdoor building structures.

[0025] Moreover, the spacing between adjacent gratings of the fiber grating array 1 is 1 meter. Correspondingly, two adjacent holes on the hollow tube 2 are staggered on both sides of the hollow tube, and the spacing between them is 0.995 meters.

[0026] The utility model reduces the temperature conduction hysteresis caused by the optical cable packaging structure by drilling holes on both sides of the hollow tube and filling the inside with heat-conducting material, improves the temperature response rate, and realizes real-time monitoring; the fiber grating array is packaged in a spiral shape, and there is 5 meters of optical fiber redundancy per kilometer of optical cable, which ensures that the optical cable is not affected by external stress; at the same time, according to the redundancy ratio of the fiber grating array, the hole spacing on both sides of the hollow tube is 0.995 meters, so that the point positioning of the fiber grating array is realized; and aramid fiber and UV-proof sheath are used as protective structures for long-term monitoring of large outdoor building structures.

[0027] The above is only an explanation of the preferred embodiments of the utility model, which cannot be understood as a limitation of the claims. Any equivalent structure or equivalent process changes made using the utility model specification are included in the patent protection scope of the utility model.

Claims

1. A temperature sensing optical cable based on fiber grating array, Features: It includes a fiber grating array, a hollow tube and a sheath. The fiber grating array is longer than the hollow tube and is packaged in a spiral shape inside the hollow tube. The two ends of the fiber grating array are flush with the two ends of the hollow tube respectively. The hollow tube is also filled with heat-conducting material. The fiber grating array has a plurality of gratings evenly spaced along the length direction and holes are opened on the corresponding hollow tube according to the point positions of each grating. The hollow tube is wrapped with aramid fiber, and the sheath is arranged outside the hollow tube. The hollow tube is a metal tube and the sheath is an anti-ultraviolet sheath.

2. The temperature sensing optical cable based on fiber grating array according to claim 1, Features: Adjacent holes are arranged alternately on both sides of the hollow tube.

3. The temperature sensing optical cable based on fiber grating array according to claim 2, Features: The spacing between adjacent gratings is 1 meter, and the spacing between adjacent holes along the length of the optical cable is 0.995 meters.

4. The temperature sensing optical cable based on fiber grating array according to claim 1, Features: For every kilometer of optical cable, the length of the fiber grating array is 1005 meters and the length of the hollow tube is 1000 meters.

5. The temperature sensing optical cable based on fiber grating array according to claim 1, Features: The points of each grating are aligned one by one with the holes opened on the corresponding hollow tube.

6. The temperature sensing optical cable based on fiber grating array according to claim 1, Features: The outside of the hollow tube is wrapped with aramid fibers, and its tensile and compressive strength reaches 400N.

7. The temperature sensing optical cable based on fiber grating array according to claim 1, Features: The metal pipe is a stainless steel pipe.

8. The temperature sensing optical cable based on fiber grating array according to claim 1, Features: The sheath is polyvinyl chloride.

9. The temperature sensing optical cable based on fiber grating array according to claim 1, Features: The thermal conductive material is thermal grease.

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