Temperature self-compensated strain sensing optical cable

Abstract

The utility model discloses a kind of temperature self-compensating strain sensing optical cable, it is related to optical fiber sensing technical field, including optical cable sheath, strain sensing unit and temperature sensing unit;The strain sensing unit is coaxially extended and arranged in the inside of the optical cable sheath, and it uses distributed strain sensing structure;The temperature sensing unit is coaxially extended and arranged in the inside of the optical cable sheath, and it uses distributed temperature sensing structure.Based on the technical scheme disclosed in the utility model, the temperature self-compensating function of sensing system is realized, the strain interference of sensing system itself is overcome, the deviation of monitoring result is reduced, and the accuracy of strain monitoring result is improved.

Description

Technical Field

[0001] This utility model relates to the field of fiber optic sensing technology, specifically to a temperature self-compensating strain sensing optical cable. Background Technology

[0002] With the development of the Internet of Things and sensing technology, distributed fiber optic strain sensing technology, due to its strong anti-interference ability, wide monitoring range, high precision and high spatial resolution, is increasingly valued and promoted in the field of structural health monitoring of large-scale geotechnical engineering. Examples include BOTDR (Brillouin Optical Time Domain Reflectometer) and BOTDA (Brillouin Optical Time Domain Analyzer) technologies based on the Brillouin scattering signal monitoring principle, as well as grating array strain sensing fiber optic technology based on ultra-weak reflectivity Bragg grating sensing technology.

[0003] In related technologies, because the strain of a material or structure is affected by the combined effects of external stress and temperature changes, the strain monitored by the strain sensor in the strain monitoring system comes from the strain of the measured object and the strain generated by the temperature of the sensor itself. The strain generated by the temperature of the sensor itself will affect the monitoring results and cause deviations in the strain monitoring results. Utility Model Content

[0004] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a temperature self-compensating strain sensing optical cable to solve the technical problem that strain monitoring is affected by the strain of the sensor itself, resulting in deviations in the strain monitoring results.

[0005] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: This utility model provides a temperature self-compensating strain sensing optical cable, comprising: Optical cable sheath; A strain sensing unit, extending in the same direction inside the optical cable sheath, employs a distributed strain sensing structure; and The temperature sensing unit extends in the same direction and is disposed inside the optical cable sheath, and adopts a distributed temperature sensing structure.

[0006] In some embodiments, the strain sensing unit includes: Distributed strain sensing optical fibers, extending in the same direction, are disposed inside the optical cable sheath; and A strain-encapsulating sheath extends in the same direction and is disposed inside the optical cable sheath, and is fixedly sleeved on the outside of the distributed strain-sensing optical fiber.

[0007] In some embodiments, the distributed strain sensing fiber is a single-mode communication fiber, the strain encapsulation sheath is disposed on the outside of the single-mode communication fiber using a polymer material tight-packing extrusion encapsulation process, and the strain sensing unit realizes distributed strain sensing through BOTDR and BOTDA demodulation.

[0008] In some embodiments, the distributed strain sensing fiber is a grating array sensing fiber, and the strain encapsulation sheath is disposed on the outside of the grating array sensing fiber using a polymer tight-buffered fiber and a spiral armor inner fixed-point process, so that the strain sensing unit forms a continuous large gauge length grating array strain sensing unit, and the strain sensing unit realizes distributed strain sensing through grating wavelength demodulation.

[0009] In some embodiments, the temperature sensing unit includes: Distributed temperature sensing optical fibers extend in the same direction and are disposed inside the optical cable sheath; and A temperature encapsulation sheath extends in the same direction and is disposed inside the optical cable sheath, and is sleeved on the outside of the distributed temperature sensing optical fiber.

[0010] In some embodiments, the distributed temperature sensing optical fiber is a multimode communication optical fiber, the temperature encapsulation sheath is disposed on the outside of the multimode communication optical fiber using a polymer tight-buffered or oil-filled loose-buffered encapsulation process, and the temperature sensing unit uses DTS demodulation to realize distributed temperature sensing.

[0011] In some embodiments, the distributed temperature sensing fiber is a grating array sensing fiber, the temperature encapsulation sheath is disposed on the outside of the grating array sensing fiber using a metal dry loose tube encapsulation process, and the temperature sensing unit realizes distributed temperature sensing through grating wavelength demodulation.

[0012] In some embodiments, the temperature self-compensating strain sensing optical cable further includes a plurality of reinforcing cores, which extend in the same direction and are disposed inside the optical cable sheath, and are respectively located on both sides of the strain sensing unit.

[0013] In some embodiments, the optical cable sheath has a flat structure and grooves are symmetrically arranged on its two sides.

[0014] In some embodiments, the optical cable sheath is provided with chamfers and rounded corners on opposite sides, and the chamfers and rounded corners are respectively close to the strain sensing unit and the temperature sensing unit.

[0015] Compared with the prior art, the present invention provides a temperature self-compensating strain sensing optical cable. By simultaneously placing a strain sensing unit and a temperature sensing unit in a single sensing optical cable, the strain sensing unit is cross-sensitive to stress and temperature, while the temperature sensing unit only monitors temperature changes. Through Boolean operations on the two data quantities, high-precision analysis of the strain of the measured object can be achieved, thereby realizing the temperature self-compensation function of the sensing system. This overcomes the strain interference of the sensing system itself, reduces the deviation of the monitoring results, and improves the accuracy of the strain monitoring results. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a temperature self-compensating strain sensing optical cable in one embodiment of this utility model.

[0017] Explanation of reference numerals in the attached diagram: 1. Optical cable sheath; 11. Chamfer; 12. Rounded corner; 13. Groove; 2. Strain sensing unit; 21. Distributed strain sensing fiber; 22. Strain encapsulation sheath; 3. Temperature sensing unit; 31. Distributed temperature sensing fiber; 32. Temperature encapsulation sheath; 4. Reinforcing core. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0019] To address the aforementioned technical problems, this utility model provides a temperature self-compensating strain sensing optical cable, which enables the temperature self-compensation function of the sensing system to overcome strain interference from the sensing system itself, reduce the deviation of monitoring results, and improve the accuracy of strain monitoring results.

[0020] Please see Figure 1 , Figure 1 This is a schematic diagram of the overall structure of a temperature self-compensating strain sensing optical cable in one embodiment of the present invention. The temperature self-compensating strain sensing optical cable includes an optical cable sheath 1, a strain sensing unit 2, and a temperature sensing unit 3. Both the strain sensing unit 2 and the temperature sensing unit 3 are disposed inside the optical cable sheath 1. The strain sensing unit 2 is cross-sensitive to stress and temperature, while the temperature sensing unit can monitor temperature changes.

[0021] In practical applications, based on the data collected by strain sensing unit 2 and temperature sensing unit 3, Boolean operations on the two data quantities can be performed to achieve high-precision analysis of the strain of the measured object, thereby realizing the temperature self-compensation function of the sensing system.

[0022] In this embodiment, the strain sensing unit 2 is arranged in the same direction as the optical cable sheath 1 inside the optical cable sheath 1, and it can adopt a distributed strain sensing structure.

[0023] Specifically, the strain sensing unit 2 may include a distributed strain sensing fiber 21 and a strain encapsulation sleeve 22, with the distributed strain sensing fiber 21 located inside the strain encapsulation sleeve 22.

[0024] In one embodiment, the distributed strain sensing fiber 21 can be a single-mode communication fiber; the strain encapsulation sheath 22 can be formed on the outside of the single-mode communication fiber using a polymer material tight-packing extrusion encapsulation process to form the strain sensing unit 2. In this case, the strain sensing unit 2 can realize distributed strain sensing through BOTDR and BOTDA demodulation.

[0025] In another embodiment, the distributed strain sensing fiber 21 can also be a grating array sensing fiber; and the strain encapsulation sheath 22 can be formed on the outside of the grating array sensing fiber using a polymer tight-buffered fiber and a spiral armor inner fixed point process, so that the strain sensing unit 2 constitutes a continuous large gauge length grating array strain sensing unit 2, and the continuous large gauge length grating array strain sensing unit 2 can realize distributed strain sensing through grating wavelength demodulation.

[0026] It should be noted that the above-mentioned polymer material tight-packing extrusion encapsulation process and polymer tight-buffered optical fiber and spiral armor inner positioning process are all existing technologies in this field. In this application, the strain encapsulation sheath 22 is defined by existing processes. The focus is not on the process part, but on emphasizing that the specific structure of the strain encapsulation sheath 22 is formed according to the relevant processes, so as to facilitate those skilled in the art to understand the specific structure of the strain encapsulation sheath 22 in the relevant embodiments.

[0027] In this embodiment, the temperature sensing unit 3 is arranged in the same direction as the optical cable sheath 1 inside the optical cable sheath 1, and it can adopt a distributed temperature sensing structure.

[0028] Specifically, the temperature sensing unit 3 may include a distributed temperature sensing fiber 31 and a temperature encapsulation sleeve 32, with the distributed temperature sensing fiber 31 located inside the temperature encapsulation sleeve 32.

[0029] In one embodiment, the distributed temperature sensing fiber 31 can be a multimode communication fiber; the strain-encapsulated sheath 22 can be formed on the outside of the multimode communication fiber using a polymer tight-fitting or oil-filled loose-fitting encapsulation process to form the temperature sensing unit 3. In this case, the temperature sensing unit 3 can use DTS demodulation to achieve distributed temperature sensing.

[0030] In another embodiment, the distributed temperature sensing fiber 31 can also be a grating array sensing fiber; and the temperature encapsulation sleeve 32 can be formed on the outside of the grating array sensing fiber using a metal dry loose tube encapsulation process, so that the temperature sensing unit 3 constitutes a grating array temperature sensing unit 3, and the grating array temperature sensing unit 3 can realize distributed strain sensing through grating wavelength demodulation.

[0031] Similarly, the aforementioned polymer tight-fitting or oil-filled loose-fitting encapsulation process and metal dry loose-fitting encapsulation process are all existing technologies in this field. The specific structure of the strain-encapsulated sheath 22 can be defined by these existing processes, and will not be elaborated here.

[0032] In this embodiment, the optical cable sheath 1 can be formed on the outside of the strain sensing unit 2 and the temperature sensing unit 3 by thermoplastic polymer material extrusion molding process, so that the strain sensing unit 2 and the temperature sensing unit 3 are arranged side by side inside the optical cable sheath 1.

[0033] In one embodiment, please refer to Figure 1 The optical cable sheath 1 can be configured as a flat structure to facilitate installation, labeling, or embedding. In this case, the strain sensing unit 2 and temperature sensing unit 3 mentioned above can be arranged inside the optical cable sheath 1 along the width direction.

[0034] Based on this, in one embodiment, chamfers 11 and rounded corners 12 can be respectively provided on opposite sides of the optical cable sheath 1. The chamfer 11 can be provided on the side of the optical cable sheath 1 closer to the strain sensing unit 2, while the rounded corner 12 can be provided on the side of the optical cable sheath 1 closer to the temperature sensing unit 3. In this way, users can easily distinguish the locations of the strain sensing unit 2 and the temperature sensing unit 3 from their appearance.

[0035] In one embodiment, grooves 13 may be symmetrically provided on opposite sides of the optical cable sheath 1 in the height direction. The grooves 13 may be right-angled grooves, or they may be U-shaped grooves or other shaped grooves depending on the size of the optical cable sheath 1. There is no specific limitation on this.

[0036] At this time, in the width direction of the optical cable sheath 1, the groove 13 is located between the strain sensing unit 2 and the temperature sensing unit 3. During construction, it can facilitate branch stripping and protection, and increase the bonding contact area between the strain sensing unit 2 and the measured object, thereby improving the coupling strength and the strain transmission of the system.

[0037] The material and outer diameter of the temperature sensing unit 3 can be defined according to the length requirements, thereby adapting to strain sensing units 2 with different outer diameters.

[0038] It should be noted that in this embodiment, the optical cable sheath 1 can be formed by thermoplastic polymer material extrusion molding process, which facilitates large-scale continuous production; in practical applications, the material of the optical cable sheath 1 can be any one of LDPE, LLDPE, MDPE, HDPE, PA, PVC, LSZH, TPE and TPU, and there is no specific limitation on this.

[0039] Meanwhile, the width and height of the optical cable sheath 1 depend on the requirements of different application environments for the material and mechanical properties of the optical cable sheath 1, and no specific limitations are required.

[0040] In addition, the material and outer diameter of the temperature sensing unit 3 can be defined according to the length requirements, so as to adapt to strain sensing units 2 with different outer diameters. Then, different materials and minimum wall thicknesses can be selected for the optical cable sheath 1 according to different application scenarios, and finally the width and height of the optical cable sheath 1 can be defined.

[0041] In this embodiment, the temperature self-compensating strain sensing optical cable may also include multiple reinforcing cores 4, which may extend in the same direction along the optical cable sheath 1 and be disposed inside the optical cable sheath 1 to improve the mechanical tensile strength of the optical cable.

[0042] In one embodiment, please refer to Figure 1 Two reinforcing cores 4 can be provided. The two reinforcing cores 4 can be provided on opposite sides of the strain sensing unit 2. For example, one reinforcing core 4 can be provided on the side of the strain sensing unit 2 near the chamfer 11, while the other reinforcing core 4 can be provided between the strain sensing unit 2 and the temperature sensing unit 3.

[0043] Based on this, the material of the reinforcing core 4 can be FRP, steel wire, copper wire, aramid, and metal-edged braided yarn, etc., and there is no specific limitation on this.

[0044] It is understandable that the material and outer diameter of the reinforcing core 4 can be determined according to the overall mechanical performance requirements and outline size requirements of the sensing optical cable. For example, the material of the reinforcing core 4 can be any of FRP, steel wire, copper wire, aramid, and metal-edged braided wire, without specific limitations.

[0045] Meanwhile, by setting the aforementioned reinforcing core 4 inside the optical cable sheath 1, the mechanical tensile strength of the sensing optical cable can be improved, thereby increasing the survival rate of the sensing optical cable during engineering installation.

[0046] It should be noted that in this embodiment, by simultaneously placing the strain sensing unit 2 and the temperature sensing unit 3 in a single sensing optical cable, the strain sensing unit 2 is cross-sensitive to stress and temperature, while the temperature sensing unit 3 only monitors temperature changes. Through Boolean operations on the two data quantities, high-precision analysis of the strain of the measured object can be achieved, thereby realizing the temperature self-compensation function of the sensing system to overcome the strain interference of the sensing system itself, reduce the deviation of the monitoring results, and improve the accuracy of the strain monitoring results.

[0047] In the description of this application, it should be noted that the terms "upper" and "lower," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element 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 application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" 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; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0048] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0049] The specific embodiments of this utility model described above do not constitute a limitation on the scope of protection of this utility model. Any other corresponding changes and modifications made based on the technical concept of this utility model should be included within the scope of protection of the claims of this utility model.

Claims

1. A temperature-self-compensating strain-sensing optical cable, characterized in that, include: Optical cable sheath; The strain sensing unit extends in the same direction and is disposed inside the optical cable sheath, and adopts a distributed strain sensing structure. as well as The temperature sensing unit extends in the same direction and is disposed inside the optical cable sheath, and adopts a distributed temperature sensing structure.

2. The temperature self-compensating strain sensing optical cable according to claim 1, characterized in that, The strain sensing unit includes: Distributed strain sensing optical fibers, extending in the same direction, are disposed inside the optical cable sheath; and A strain-encapsulating sheath extends in the same direction and is disposed inside the optical cable sheath, and is fixedly sleeved on the outside of the distributed strain-sensing optical fiber.

3. The temperature self-compensating strain sensing optical cable according to claim 2, characterized in that, The distributed strain sensing fiber is a single-mode communication fiber. The strain encapsulation sheath is set on the outside of the single-mode communication fiber using a polymer material tight-packing extrusion encapsulation process. The strain sensing unit realizes distributed strain sensing through BOTDR and BOTDA demodulation.

4. The temperature self-compensating strain sensing optical cable according to claim 2, characterized in that, The distributed strain sensing fiber is a grating array sensing fiber. The strain encapsulation sheath is set on the outside of the grating array sensing fiber using a polymer tight-buffered fiber and a spiral armor inner fixed point process, so that the strain sensing unit forms a continuous large gauge length grating array strain sensing unit, and the strain sensing unit realizes distributed strain sensing through grating wavelength demodulation.

5. The temperature self-compensating strain sensing optical cable according to claim 1, characterized in that, The temperature sensing unit includes: Distributed temperature sensing optical fibers extend in the same direction and are disposed inside the optical cable sheath; and A temperature encapsulation sheath extends in the same direction and is disposed inside the optical cable sheath, and is sleeved on the outside of the distributed temperature sensing optical fiber.

6. The temperature self-compensating strain sensing optical cable according to claim 5, characterized in that, The distributed temperature sensing fiber is a multimode communication fiber. The temperature encapsulation sleeve is set on the outside of the multimode communication fiber using a polymer tight-buffered or oil-filled loose-buffered encapsulation process. The temperature sensing unit uses DTS demodulation to realize distributed temperature sensing.

7. The temperature self-compensating strain sensing optical cable according to claim 5, characterized in that, The distributed temperature sensing fiber is a grating array sensing fiber. The temperature encapsulation sheath is set on the outside of the grating array sensing fiber using a metal dry loose tube encapsulation process. The temperature sensing unit realizes distributed temperature sensing through grating wavelength demodulation.

8. The temperature self-compensating strain sensing optical cable according to claim 1, characterized in that, Also includes: Multiple reinforcing cores extend in the same direction and are disposed inside the optical cable sheath, respectively located on both sides of the strain sensing unit.

9. The temperature self-compensating strain sensing optical cable according to any one of claims 1-8, characterized in that, The optical cable sheath has a flat structure and grooves are symmetrically arranged on its two sides.

10. The temperature self-compensating strain sensing optical cable according to claim 9, characterized in that, The optical cable sheath has chamfers and rounded corners on opposite sides, respectively, with the chamfers and rounded corners located near the strain sensing unit and the temperature sensing unit.

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