A high-density long-distance continuous high-precision temperature measurement sensing optical cable and a continuous preparation method thereof

Abstract

The application discloses a kind of high-density long-distance continuous high-precision temperature measurement sensing optical cable and continuous preparation method, including dense distribution type strain optical fiber, dense distribution type strain optical fiber is tightly fitted with tight sheath outside, multiple sensitive elements are intervally sheathed outside tight sheath along length direction, each sensitive element is fixedly arranged corresponding to each grid area of dense distribution type strain optical fiber;Sensitive element is used as carrier by effectively using the characteristics that sensitive element is stretched or compressed with the change of temperature, grid area can be deformed with sensitive element, high-precision monitoring of external temperature is realized, through the interval, multiple, continuous arrangement of sensitive element corresponding to grid area, continuity of measuring point is realized while high-precision monitoring;And, the optical cable can be long-distance continuous processing and form long-distance continuous high-precision temperature measurement sensing optical cable, so that long-distance, high-precision continuous temperature measurement is realized, especially suitable for kilometer length temperature monitoring.

Description

Technical Field

[0001] This invention relates to the field of optical cable monitoring technology, and in particular to a high-density, long-distance, continuous, high-precision temperature sensing optical cable and its continuous manufacturing method. Background Technology

[0002] Fiber optic monitoring technology is an emerging technology that uses fiber optic sensors to continuously monitor the temperature and moisture content of rock masses at multiple points. Its development can be traced back to the 1980s, when fiber optic sensor technology was first applied to structural health monitoring. Subsequently, fiber optic sensor technology has been widely used in civil engineering, geological exploration, and other fields.

[0003] In scenarios such as long-distance pipelines (oil and gas pipelines, heating networks, cable tunnels), large-scale energy storage power stations, mine roadways, dam slopes, rail transit, highway subgrades, large grain warehouses, and power transmission lines, safety risks are hidden, along the route, and sudden. It is necessary to conduct continuous real-time temperature monitoring along the entire route without blind spots to accurately locate abnormal heat points, leakage points, and fire hazard points, so as to achieve early warning, in-process monitoring, and post-event tracing.

[0004] Existing traditional temperature sensors (thermocouples, platinum resistance thermometers PT100, infrared thermometers, fiber optic gratings FBG) have significant shortcomings: they can only measure temperature at fixed points, have limited deployment density, and cannot achieve continuous spatial temperature measurement; when laid over long distances, they suffer from signal attenuation, complex wiring, high failure rate, and high cost, making it difficult to meet the needs of kilometer-level and meter-level spatial resolution, high precision, and long-term stable monitoring in the above scenarios.

[0005] FBG optical fiber, as a high-precision temperature sensor, can form multi-point measurement through fusion splicing, but the number of splices is limited, making it impossible to form long-distance (kilometer-level) continuous monitoring; while existing dense distributed temperature measurement optical cables can achieve long-distance continuous temperature measurement, their temperature coefficient is only 0.01nm / ℃, which is low in accuracy and cannot be used in places with high temperature accuracy requirements. Summary of the Invention

[0006] To address the aforementioned issues, this application provides a structurally sound, high-density, long-distance, continuous, high-precision temperature sensing optical cable and a continuous fabrication method, thereby enabling long-distance, high-precision continuous temperature measurement, particularly suitable for temperature monitoring at the kilometer level.

[0007] The technical solution adopted in this invention is as follows: A high-density, long-distance, continuous, high-precision temperature sensing optical cable includes a densely distributed strain fiber. The densely distributed strain fiber is tightly fitted with a tight-packed sheath. Multiple sensitive elements are spaced apart along the length of the tight-packed sheath, and each sensitive element is fixedly arranged corresponding to a grating region of the densely distributed strain fiber.

[0008] As a further improvement to the above technical solution: Each sensitive element is a circular tube structure formed by rolling and fixing corresponding thin metal sheets to the outside of a tightly wrapped sheath.

[0009] The metal sheet is an aluminum sheet with a dimension of 40mm-80mm along the length of the densely distributed strained optical fiber and a thickness of 0.15mm-0.3mm.

[0010] Adhesive is uniformly applied between the inner wall of the sensitive element and the outer wall of the sheath.

[0011] Each grating region on the densely distributed strain fiber is located in the middle of its corresponding sensing element.

[0012] The sensitive element is covered by an armored tube, and the inner side of the armored tube forms an accommodating space. The densely distributed strain optical fiber and its outer tightly wrapped sheath, along with multiple sensitive elements, are collectively enclosed within the accommodating space.

[0013] The outer side of the armored tube is fitted with a steel strand, and the outer side of the steel strand is fitted with an outer sheath.

[0014] A continuous fabrication method for the high-density, long-distance, continuous, high-precision temperature-sensing optical cable includes the following steps: Customized densely distributed strain optical fibers are produced according to the grid spacing requirements. A sheath is applied to densely distributed strain optical fibers using a sheathing machine to form a tight-buffered optical cable. Glue is evenly applied to the sides of each aluminum sheet, and each aluminum sheet is aligned with the center of each grating region on the densely distributed strain optical fiber. The aluminum sheet is rolled into a circular tube structure that is sleeved and fixed to the outside of the tightly wrapped optical cable using a rolling press, forming sensitive elements arranged at intervals along the length of the tightly wrapped optical cable, thus forming the fiber core. The fiber core is sequentially processed into armor tubes on a tube-making machine, into steel strands on a cabling machine, and into an outer sheath on a sheathing machine.

[0015] As a further improvement to the above technical solution: While covering the tight-packed sheath, inkjet markings are applied to the outside of the tight-packed sheath, with the inkjet markings corresponding to each grating region of the densely distributed strain optical fiber; the tight-packed optical cable is then wound into a coil.

[0016] The thickness of the adhesive coating on the side of the aluminum sheet is 0.5mm ± 0.05mm.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention effectively utilizes the property of the sensitive element to stretch or compress with temperature changes, using the sensitive element as a carrier, and the grid area can deform in tandem with the sensitive element, thereby achieving high-precision monitoring of the external temperature; by arranging the sensitive elements at intervals, multiple, and continuously corresponding to the grid area, the continuity of the measurement points is achieved while maintaining high-precision monitoring; furthermore, the optical cable can be continuously processed over long distances to form a long-distance continuous high-precision temperature sensing optical cable, thereby achieving long-distance, high-precision continuous temperature measurement, which is especially suitable for temperature monitoring at the kilometer level. The present invention also includes the following advantages: Using aluminum sheets as a carrier, the aluminum sheets are effectively, reliably, and stably fixed to the corresponding grating area of ​​the optical fiber through a process of glue and rolling to form a sensitive element. Its sensing accuracy can reach 38pm / nm, which is about four times that of ordinary temperature optical cables (10pm / nm), greatly improving the accuracy of temperature measurement.

[0018] By encasing a tight-packed sheath around the densely distributed strain optical fiber and then fixing a sensitive element outside the tight-packed sheath, the strength of the optical fiber fabrication is effectively increased, enabling the fabrication of kilometer-level optical cables and helping to solve the problem of long-distance continuous high-precision temperature monitoring in existing technologies. By installing an armored tube, the strength and tensile properties of the optical cable can be increased, preventing excessive stretching that could break the cable. At the same time, it also creates a containment space to protect the internal optical fibers. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the metal sheet being rolled and pressed into a sensitive element according to the present invention.

[0021] Figure 3 This is a graph showing the actual temperature measurement during the use of this invention.

[0022] The components include: 1. outer sheath; 2. steel strand; 3. armored tube; 4. sensing element; 5. adhesive; 6. tight-packed sheath; and 7. densely distributed strain optical fiber. Detailed Implementation

[0023] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0024] like Figure 1 As shown, a high-density, long-distance, continuous, high-precision temperature sensing optical cable of this embodiment includes a densely distributed strain fiber 7. The densely distributed strain fiber 7 is tightly fitted with a tight-packed sheath 6. Multiple sensitive elements 4 are spaced along the length direction outside the tight-packed sheath 6. Each sensitive element 4 is fixedly arranged corresponding to each grid area of ​​the densely distributed strain fiber 7.

[0025] In this embodiment, the characteristic of the sensitive element 4 being stretched or compressed with temperature changes is effectively utilized. The sensitive element 4 is used as a carrier, and the grid area can deform in tandem with the sensitive element 4, thereby achieving high-precision monitoring of the external temperature. By arranging the sensitive elements 4 at intervals, in multiples, and continuously corresponding to the grid area, the continuity of the measurement points can be achieved while maintaining high-precision monitoring. Furthermore, the optical cable can be continuously processed over long distances to form a long-distance continuous high-precision temperature sensing optical cable.

[0026] In this embodiment, a tight-fitting sheath 6 is fitted over the densely distributed strain fiber 7, and then the sensitive element 4 is fixed outside the tight-fitting sheath 6, instead of directly processing the bare fiber. By setting a tightly fitted tight-fitting sheath 6 outside the bare fiber, the strength of the fiber fabrication is effectively increased while ensuring that the densely distributed strain fiber 7 and the tight-fitting sheath 6 can deform together, so as to realize the fabrication of kilometer-level optical cables and help solve the problem of long-distance continuous high-precision temperature monitoring in the prior art.

[0027] like Figure 2 As shown, each sensitive element 4 is a circular tube structure formed by rolling and fixing the corresponding metal sheet to the outside of the tight-fitting sheath 6, which can effectively ensure the tight fit and fixation between the structures during the forming process.

[0028] The metal sheet is an aluminum sheet with dimensions of 40mm-80mm along the length of the densely distributed strained optical fiber 7 and a thickness of 0.15mm-0.3mm.

[0029] In this embodiment, an aluminum sheet is used as a carrier. The aluminum sheet is effectively, reliably, and stably fixed to the corresponding grating area of ​​the optical fiber through a process of glue and rolling to form a sensing element 4. Its sensing accuracy can reach 38 pm / nm, which is about four times that of ordinary temperature optical cables (10 pm / nm), greatly improving the accuracy of temperature measurement.

[0030] In this embodiment, the length of the aluminum sheet is set to 40mm-80mm, which is greater than the dimension of the gate area in the same direction, in order to avoid gate area error and ensure that the gate area can be reliably located inside the sensitive element 4.

[0031] Adhesive 5 is evenly applied between the inner wall of the sensitive element 4 and the outer wall of the tight-fitting sheath 6.

[0032] In this embodiment, glue 5 is used in combination with the rolling and pressing process to ensure that the metal sheet can be tightly attached to the grid area of ​​the optical fiber. The stretching or contraction deformation of the sensitive element 4 drives the synchronous deformation of the optical fiber, ensuring the reliability of their coordinated deformation.

[0033] Each grating region on the densely distributed strain fiber 7 is located in the center of its corresponding sensing element 4 to ensure the reliability and stability of the detection.

[0034] The outer side of the sensitive element 4 is covered by an armor tube 3, and the inner side of the armor tube 3 forms an accommodating space. The densely distributed strain optical fiber 7, its outer tightly wrapped sheath 6, and multiple sensitive elements 4 are collectively covered within the accommodating space.

[0035] By setting the armor tube 3, the strength and tensile properties of the optical cable can be increased, preventing excessive stretching and breakage. At the same time, it can also form a containment space to protect the internal optical fibers.

[0036] The outer side of the armor tube 3 is fitted with a steel strand 2, and the outer side of the steel strand 2 is fitted with an outer sheath 1.

[0037] In this embodiment, the steel strand 2 effectively increases the strength of the optical cable, ensuring that the optical cable is not easily damaged during use and extending its service life.

[0038] In this embodiment, the armor tube 3, combined with the steel strand 2 and the outer sheath 1, forms a relatively enclosed internal space, which can effectively overcome the problems of condensation and electromagnetic interference inside the optical cable in humid air, greatly extending the service life of the optical cable and improving its reliability.

[0039] This embodiment also proposes a continuous fabrication method for high-density, long-distance, continuous, high-precision temperature sensing optical cables, including the following steps: Step 1: Customize densely distributed strain fiber 7 according to the grid spacing requirements; Step 2: Use a coating machine to coat the tight-packed sheath 6 onto the densely distributed strain optical fiber 7 to form a tight-packed optical cable; In this embodiment, while covering the tight-packed sheath 6, inkjet markings are made on the outside of the tight-packed sheath 6, and the inkjet markings correspond to each grid area of ​​the densely distributed strain optical fiber 7; the tight-packed optical cable is wound into a coil.

[0040] In practice, a coating machine with length recognition function can be used to coat the tight-packed sheath 6 according to the grid spacing of the densely distributed strain fiber 7. At the same time, an inkjet printer is used to mark the grid points on the outside of the tight-packed sheath 6 according to the grid spacing. The tight-packed optical cable is then wound into a coil by the winding function on the coating machine for easy subsequent processing.

[0041] Step 3: Apply glue 5 evenly to the sides of each aluminum sheet, such as epoxy resin glue; align each aluminum sheet with the center of each grating region on the densely distributed strain optical fiber 7, and use a rolling press to roll the aluminum sheet into a round tube structure that is sleeved and fixed to the outside of the tightly wrapped optical cable, forming sensitive elements 4 arranged at intervals along the length of the tightly wrapped optical cable, thus forming the fiber core. In practice, aluminum sheets with a length of 40-80mm can be used to avoid gate area errors and ensure that the gate area is within the sensitive element 4.

[0042] In one embodiment, an aluminum sheet with a width of 4mm and a thickness of 0.2mm can be selected. In one embodiment, the thickness of the adhesive 5 coating on the side of the aluminum sheet is 0.5 mm ± 0.05 mm.

[0043] In actual operation, the marking point corresponding to the grid area on the tightly wrapped optical cable is placed at the center of the aluminum sheet, and then the aluminum sheet is rolled into a cylindrical shape by a rolling press to form the sensitive element 4.

[0044] In this embodiment, the sensitive element 4 can be set on a tightly wrapped optical cable of kilometer-long length according to actual needs.

[0045] Step 4: The fiber core is sequentially processed into armor tube 3 on the tube-making machine, steel strand 2 on the cabling machine, and outer sheath 1 on the sheathing machine to form the required high-density, long-distance, continuous, high-precision temperature-measuring optical cable.

[0046] like Figure 3 The figure shows a schematic diagram of the curve obtained by measuring the optical cable in actual use in this embodiment. The slope of 0.0288 nm / ℃ reflects the temperature sensitivity coefficient, which is significantly higher than the typical value of about 0.010~0.012 nm / ℃ for conventional bare optical fiber, effectively verifying the detection accuracy. After adopting the sensitive element 4, the thermal expansion effect of the metal material effectively amplifies the overall temperature sensitivity, achieving a typical effect enhancement. The goodness of fit is 0.9999, which is very close to 1. The data points almost perfectly fall on the straight line, with excellent linearity and no obvious nonlinearity, hysteresis or drift, indicating that the grating and the sensitive element 4 have good stability and good consistency of cooperative deformation.

[0047] The optical cable of this invention enables long-distance, high-precision continuous temperature measurement, and is especially suitable for temperature monitoring over long distances such as tunnels at the kilometer level.

[0048] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0049] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A high-density, long-distance, continuous, high-precision temperature sensing optical cable, comprising densely distributed strain optical fibers (7), characterized in that: The densely distributed strain fiber (7) is tightly fitted with a tight-packed sheath (6), and multiple sensitive elements (4) are spaced apart along the length direction on the outside of the tight-packed sheath (6). Each sensitive element (4) is fixedly arranged corresponding to each grid area of ​​the densely distributed strain fiber (7).

2. The high-density, long-distance, continuous, high-precision temperature sensing optical cable as described in claim 1, characterized in that: Each sensitive element (4) is a circular tube structure formed by rolling and fixing the corresponding metal sheet to the outside of the tight-fitting sheath (6).

3. The high-density, long-distance, continuous, high-precision temperature sensing optical cable as described in claim 2, characterized in that: The metal sheet is an aluminum sheet with a dimension of 40mm-80mm along the length of the densely distributed strained optical fiber (7) and a thickness of 0.15mm-0.3mm.

4. The high-density, long-distance, continuous, high-precision temperature sensing optical cable as described in claim 1, characterized in that: The inner wall of the sensitive element (4) and the outer wall of the tight-fitting sheath (6) are uniformly coated with adhesive (5).

5. The high-density, long-distance, continuous, high-precision temperature sensing optical cable as described in claim 1, characterized in that: Each grating region on the densely distributed strain fiber (7) is located in the middle of the corresponding sensing element (4).

6. The high-density, long-distance, continuous, high-precision temperature sensing optical cable as described in claim 1, characterized in that: The sensitive element (4) is covered with an armor tube (3) on the outside, and the inner side of the armor tube (3) forms a accommodating space. The densely distributed strain optical fiber (7) and its outer tightly wrapped sheath (6) and multiple sensitive elements (4) are together covered in the accommodating space.

7. The high-density, long-distance, continuous, high-precision temperature sensing optical cable as described in claim 6, characterized in that: The outer side of the armor tube (3) is fitted with a steel strand (2), and the outer side of the steel strand (2) is fitted with an outer sheath (1).

8. A continuous fabrication method for the high-density, long-distance, continuous, high-precision temperature sensing optical cable as described in claim 7, characterized in that: Includes the following steps: According to the requirements of grating spacing, a densely distributed strain fiber is customized (7). The tight-packed sheath (6) is applied onto the densely distributed strain optical fiber (7) using a coating machine to form a tight-packed optical cable; Apply glue evenly to the sides of each aluminum sheet (5), align each aluminum sheet with the center of each grating region on the densely distributed strain optical fiber (7), and use a rolling press to roll the aluminum sheet into a round tube structure that is sleeved and fixed on the outside of the tightly wrapped optical cable, forming sensitive elements (4) arranged at intervals along the length of the tightly wrapped optical cable, thus forming the fiber core. The fiber core is sequentially made into an armor tube on a tube-making machine (3), a steel strand on a cabling machine (2), and an outer sheath on a sheathing machine (1).

9. The continuous fabrication method of a high-density, long-distance, continuous, high-precision temperature sensing optical cable as described in claim 8, characterized in that: While covering the tight-packed sheath (6), inkjet markings are made on the outside of the tight-packed sheath (6), and the inkjet markings correspond to each grid area of ​​the densely distributed strain optical fiber (7); the tight-packed optical cable is wound into a coil.

10. The continuous fabrication method of a high-density, long-distance, continuous, high-precision temperature sensing optical cable as described in claim 8, characterized in that: The thickness of the adhesive (5) coating on the side of the aluminum sheet is 0.5mm ± 0.05mm.

Images