A fiber optic grating temperature monitoring and early warning system and method for belt conveyor idler rollers

Abstract

This invention relates to the field of safety monitoring technology for industrial conveying equipment, and in particular to a fiber Bragg grating temperature monitoring and early warning system and method for belt conveyor idlers. In the temperature monitoring and early warning system, the sensing layer, demodulation layer, and application layer are sequentially connected and work collaboratively. The sensing layer includes a distributed temperature sensing optical cable and a fixing fixture. The distributed temperature sensing optical cable includes a weak-reflection fiber Bragg grating array. The sensing unit of the weak-reflection fiber Bragg grating array is a fiber Bragg grating, and the spacing between the fiber Bragg gratings is consistent with the spacing between the idler roller shafts. Thus, on the one hand, the fiber Bragg grating spacing is completely equal to the idler roller shaft spacing, allowing the collected temperature data to accurately reflect the operating temperature of the idler roller. On the other hand, the fiber Bragg gratings and idler roller shafts are matched one-to-one, establishing a unique mapping relationship between the fiber Bragg grating sensing points and the physical positions of the idler rollers on site, solving the positioning failure problem caused by mismatched grating spacing, and eliminating the need for maintenance personnel to manually check each device individually.

Description

Technical Field

[0001] This invention relates to the field of safety monitoring technology for industrial conveying equipment, and in particular to a fiber optic grating temperature monitoring and early warning system and method for belt conveyor idlers. Background Technology

[0002] Belt conveyors are continuous conveying equipment used in industries such as mining, ports, thermal power, and chemicals for transporting bulk materials. Idler rollers, as the most frequently used and most prone to failure critical rotating components of belt conveyors, endure the pressure of the conveyor belt, material impact, and their own friction over long periods. Frequent malfunctions such as bearing jamming and insufficient lubrication lead to abnormal temperature rises in the idlers. If high-temperature idler roller malfunctions are not identified in time, they can easily ignite dust and coal dust around the conveyor belt and the belt itself, causing major safety accidents such as fires and conveyor belt tears.

[0003] Currently, the industry mainly uses two types of temperature monitoring methods for belt conveyor rollers. One type is traditional electrical temperature measurement methods such as infrared temperature measurement and thermocouple temperature measurement. This method relies on active electronic components for power supply, which poses a risk of electric spark ignition in flammable, explosive, and humid conditions such as underground mines and enclosed corridors. In addition, the wiring is complex and the resistance to electromagnetic interference is extremely poor. The other type is passive fiber optic grating temperature measurement technology. With its advantages of being passive and intrinsically safe, resistant to electromagnetic interference, long transmission distance, and high accuracy, it has gradually become the mainstream solution for temperature measurement of long-distance conveying equipment in mining and industrial areas.

[0004] However, the grating spacing inside existing commercial fiber Bragg grating sensing cables is a fixed and universal specification. Specifically, in conventional fiber Bragg grating arrays, the grating spacing is fixed and cannot be adjusted. Some gratings correspond to the position of the idler rollers, while some gratings are suspended in the conveyor belt cavity between two idler rollers. The suspended gratings collect ambient air temperature rather than the temperature of the idler roller itself, causing distortion in the temperature measurement data. In addition, fiber Bragg gratings themselves are affected by both strain and temperature. Ordinary weak fiber Bragg grating cables cannot accurately identify the actual temperature changes. At the same time, a single idler roller cannot be matched with a dedicated fiber Bragg grating sensing unit, and the system cannot establish a unique binding relationship between the grating number and the physical position of the idler roller. Even if an abnormal temperature signal is detected, it is impossible to accurately locate the specific idler roller with the temperature rise fault. Maintenance personnel still need to manually check each idler roller, which greatly reduces the efficiency of fault handling. Furthermore, invalid suspended gratings will also generate redundant optical signals, interfering with the signal recognition accuracy of the demodulation equipment, further reducing the accuracy of idler roller temperature monitoring.

[0005] Therefore, it is urgent for technical personnel to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a fiber optic grating temperature monitoring and early warning system for belt conveyor idler rollers, which aims to solve the problems of fixed grating spacing in existing fiber optic grating sensing cables, which cannot match the idler roller shaft arrangement spacing, and are prone to temperature measurement data distortion and positioning deviation of faulty idler rollers.

[0007] This invention relates to a fiber Bragg grating temperature monitoring and early warning system for belt conveyor idler rollers, comprising a sensing layer, a demodulation layer, and an application layer; the sensing layer, demodulation layer, and application layer are sequentially connected and work together to respectively realize the acquisition, signal demodulation, and early warning of belt conveyor idler roller temperature; The sensing layer includes a distributed temperature sensing optical cable and a fixing fixture; the distributed temperature sensing optical cable includes a weak reflection fiber grating array; the sensing unit of the weak reflection fiber grating array is a fiber grating, the middle section is a signal transmission optical fiber, and the spacing of the fiber gratings is consistent with the spacing of the belt conveyor idler rollers; the fixing fixture attaches the distributed temperature sensing optical cable to the surface of the belt conveyor idler rollers, and each fiber grating corresponds one-to-one with the belt conveyor idler roller.

[0008] As a further improvement to the technical solution disclosed in this invention, the distributed temperature sensing optical cable also includes an elastic sensitizing element and an armored sheath; the weak reflection fiber grating array, the elastic sensitizing element and the armored sheath are arranged coaxially from the inside to the outside.

[0009] As a further improvement to the technical solution disclosed in this invention, the elastic sensitizing element is attached to the fiber grating in a one-to-one correspondence and the length is matched; the elastic sensitizing element amplifies the wavelength drift of the fiber grating through the thermal expansion coefficient matching effect, and isolates the axial and radial mechanical strain generated by the operation of the belt conveyor.

[0010] As a further improvement to the technical solution disclosed in this invention, the elastic sensitizing element adopts a segmented structure, including multiple slotted metal strips; each slotted metal strip corresponds to a fiber grating and has an equal length; the slotted metal strip is preferably made of aluminum or copper.

[0011] As a further improvement to the technical solution disclosed in this invention, the armor sleeve is a composite structure of a stainless steel braided layer and a flame-retardant polyolefin outer sleeve; the stainless steel braided layer is wrapped around the outside of the elastic sensitive element; and the flame-retardant polyolefin outer sleeve is wrapped around the outside of the stainless steel braided layer.

[0012] As a further improvement to the technical solution disclosed in this invention, the fixing fixture includes a high-strength neodymium iron boron magnet, an anti-loosening fixing bolt, and an elastic stainless steel pressure plate; the high-strength neodymium iron boron magnet is adsorbed onto the belt conveyor roller bracket or metal frame, and the adsorption force is not less than 80N; the elastic stainless steel pressure plate is arc-shaped, and its arc-shaped inner surface holds the distributed temperature sensing optical cable; the anti-loosening fixing bolt passes through the elastic stainless steel pressure plate and is threadedly connected to the high-strength neodymium iron boron magnet.

[0013] As a further improvement to the technical solution disclosed in this invention, the demodulation layer includes a weak reflection fiber grating array demodulation device; the weak reflection fiber grating array demodulation device integrates temperature and strain dual-parameter demodulation functions, and realizes spatial positioning of temperature anomaly points based on the principle of optical time-domain reflection.

[0014] As a further improvement to the technical solution disclosed in this invention, the application layer includes a map visualization module, a warning management module, and a data storage and analysis module that are loosely coupled and integrated through a standard API interface.

[0015] As a further improvement to the technical solution disclosed in this invention, the map visualization module is based on a GIS geographic information system and supports switching between two-dimensional and three-dimensional map base maps, real-time heat map rendering, and playback of historical temperature trajectories; the warning management module supports multi-level alarm strategies and dynamically configures threshold parameters according to region, equipment type, and operating conditions; the data storage and analysis module adopts a hybrid architecture of time-series database and relational database, with a built-in intelligent analysis engine to perform rolling predictions of temperature evolution trends and identify potential thermal runaway risks.

[0016] Furthermore, the present invention also discloses a temperature monitoring and early warning method, which is implemented by means of the above-mentioned fiber optic grating temperature monitoring and early warning system for belt conveyor idler rollers; Temperature monitoring and early warning methods include the following steps: S1. Based on the actual spacing of the idlers along the entire belt conveyor, pre-write a weak reflection fiber grating array whose spacing is completely consistent with the spacing of the idler roller shaft. S2. The distributed temperature sensing optical cable with integrated weak reflection fiber grating array is continuously laid along the axis of the idler roller shaft. The distributed temperature sensing optical cable is made to form a surface contact with the surface of each idler roller shaft by fixing clamps, and a unique spatial correspondence between each fiber grating and the idler roller shaft is established. S3. The demodulation layer emits narrowband probe light pulses to the weakly reflective fiber Bragg grating array, receives the reflected light signals returned by each fiber Bragg grating based on the principle of optical time-domain reflection, identifies the spatial position of each fiber Bragg grating by the time difference of the reflected light, calculates the real-time temperature of the corresponding roller by the wavelength offset of the reflected light, and filters out invalid light signals from each signal transmission fiber. S4. The application layer establishes a mapping table for the relationship between idler position, fiber optic grating number, and temperature data. It compares the temperature data of all idlers on the belt conveyor with the preset threshold in real time. When the temperature of a single idler exceeds the first-level threshold or the temperature of multiple adjacent idlers is synchronously abnormal, it outputs the corresponding level of warning information and displays the precise location of the abnormal idler.

[0017] In practical applications, the fiber optic grating temperature monitoring and early warning system for belt conveyor idlers disclosed in this invention can achieve at least the following beneficial technical effects, specifically: 1) This solution abandons the existing design of using a universal fixed grating spacing in fiber Bragg grating sensing cables. Instead, it customizes a low-reflection fiber Bragg grating array based on the actual arrangement spacing of the conveyor belt rollers, ensuring that the fiber Bragg grating spacing is completely consistent with the roller shaft spacing. This solution fundamentally solves the inherent defect of mismatch between traditional grating spacing and roller arrangement dimensions, effectively avoiding the phenomenon of grating suspension during temperature measurement and eliminating the problem of temperature data distortion caused by ambient temperature. Simultaneously, the fiber Bragg grating is encased in metal components to isolate axial and radial mechanical strain interference generated by the conveyor belt operation, ensuring that the fiber Bragg grating only collects the temperature of the roller shaft itself. Ultimately, this guarantees that the collected temperature data can truly and accurately reflect the operating temperature of the roller itself. 2) By using a fixing clamp, the distributed temperature sensing optical cable is tightly attached to the surface of the idler roller shaft, realizing a one-to-one matching between the fiber optic grating and the idler roller shaft. This establishes a unique mapping relationship between the fiber optic grating sensing point and the physical position of the idler roller on site, thus completely solving the problem of large fault location deviation and inability to accurately locate faulty idlers in traditional monitoring systems. It eliminates the need for maintenance personnel to manually check each device one by one, effectively solving the problem of positioning failure caused by mismatched grating spacing. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the layout of the fiber optic grating temperature monitoring and early warning system for belt conveyor idlers disclosed in this invention.

[0020] Figure 2 This is a schematic diagram of the fixing method of the distributed temperature sensing optical cable in the belt conveyor idler roller fiber grating temperature monitoring and early warning system disclosed in this invention.

[0021] Figure 3 This is a flowchart of the fiber optic grating temperature monitoring and early warning method for belt conveyor idler rollers disclosed in this invention.

[0022] 1-Sensing Layer; 11-Distributed Temperature Sensing Optical Cable; 12-Fixing Fixture; 121-High-Strength Neodymium Iron Boron Magnet; 122-Anti-Loosening Fixing Bolt; 123-Elastic Stainless Steel Pressure Plate; 2-Demodulation Layer; 21-Weak Reflection Fiber Bragg Grating Array Demodulation Equipment; 3-Application Layer; 31-Map Visualization Module; 32-Warning Management Module; 33-Analysis Module. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. Figure 1 The diagram shows the layout of the fiber optic grating temperature monitoring and early warning system for belt conveyor idlers disclosed in this invention. It can be seen that it mainly consists of three parts: a sensing layer 1, a demodulation layer 2, and an application layer 3. The sensing layer 1, demodulation layer 2, and application layer 3 are sequentially connected to an industrial Ethernet network via fiber optic communication links. Working together, they can sequentially complete the accurate acquisition of idler temperatures across the entire belt conveyor line, optical signal demodulation and conversion, data correlation analysis, and tiered early warning push, achieving all-weather, all-time, high-precision online monitoring and fault early warning of idler operating temperatures under flammable, explosive, and humid conditions.

[0024] like Figure 1 , Figure 2 As shown, the sensing layer 1 mainly consists of a distributed temperature sensing optical cable 11 and multiple sets of fixing clamps 12. The distributed temperature sensing optical cable 11, as the core carrier for temperature sensing, is continuously laid along the axial direction of the idler roller shaft of the belt conveyor and directly contacts the surface of the idler roller shaft to collect real-time temperature signals of the idler roller body. The multiple sets of fixing clamps 12 are equally spaced along the laying direction of the distributed temperature sensing optical cable 11 to tightly adhere and fix the distributed temperature sensing optical cable 11 to the surface of the idler roller shaft.

[0025] like Figure 1 As shown, demodulation layer 2 is located in the central control room along the belt conveyor and is directly connected to sensing layer 1 via single-mode optical fiber. It is used to receive the reflected light signal transmitted by sensing layer 1 and interpret it into identifiable temperature data. Application layer 3 is deployed on an industrial cloud platform or local server and communicates with demodulation layer 2 via standard industrial Ethernet. It is used to realize the visualization of temperature data, anomaly warning and intelligent analysis.

[0026] It is particularly noteworthy that the distributed temperature sensing optical cable 11 integrates a weak reflection fiber grating array; the sensing unit of the weak reflection fiber grating array is a fiber grating, and the signal transmission optical fiber is between adjacent fiber gratings. Moreover, the writing spacing of the fiber gratings is completely consistent with the actual roller shaft arrangement spacing of the belt conveyor roller. This facilitates the accurate correspondence between the fiber grating placement points and the roller installation position, thereby ensuring that the collected temperature data accurately reflects the operating temperature of the roller body.

[0027] Furthermore, the distributed temperature sensing optical cable 11 preferably adopts a three-layer coaxial composite structure, consisting of a weak-reflection fiber Bragg grating array, an elastic sensitizing element, and an armored sheath, from the inside out. The elastic sensitizing element is fitted one-to-one with each fiber Bragg grating in the weak-reflection fiber Bragg grating array, and the length of a single elastic sensitizing element perfectly matches the length of the corresponding fiber Bragg grating. The elastic sensitizing element amplifies the wavelength shift of the fiber Bragg grating caused by temperature through the thermal expansion coefficient matching effect, improving temperature detection sensitivity. Simultaneously, it isolates the axial tensile and radial compressive mechanical strain generated during the operation of the belt conveyor, eliminating the influence of strain interference on the accuracy of temperature measurement.

[0028] As a preferred embodiment, the elastic sensitizing element adopts a segmented independent structure, including multiple slotted metal strips; each slotted metal strip corresponds to a fiber Bragg grating, and the lengths of each slotted metal strip are equal. The slotted metal strips are made of aluminum or copper, which have a high coefficient of thermal expansion and good thermal conductivity, to improve the sensitizing effect and simultaneously achieve rapid heat conduction between the idler roller shaft and the fiber Bragg grating.

[0029] The armored sheath is a composite structure consisting of a stainless steel braided layer and a flame-retardant polyolefin outer sheath. The stainless steel braided layer tightly wraps around the outside of the elastic sensitizing element, providing excellent tensile, impact, and abrasion resistance, effectively protecting the internal fiber optic grating array from external damage such as material impact and mechanical scratches. The flame-retardant polyolefin outer sheath wraps around the outside of the stainless steel braided layer, providing flame retardancy, moisture resistance, and corrosion resistance, making it suitable for long-term use in harsh industrial conditions such as underground mines and enclosed corridors.

[0030] like Figure 2 As shown, the fixing clamp 12 mainly consists of a high-strength neodymium iron boron magnet 121, an anti-loosening fixing bolt 122, and an elastic stainless steel pressure plate 123. The high-strength neodymium iron boron magnet 121 is adsorbed onto the belt conveyor roller bracket or metal frame, and the vertical adsorption force of a single magnet is not less than 80N, ensuring that the fixing clamp 12 does not shift or fall off under belt conveyor vibration conditions. The elastic stainless steel pressure plate 123 has an arc-shaped structure, and its arc-shaped inner surface completely conforms to the outer contour of the distributed temperature sensing optical cable 11, used to hold and fix the distributed temperature sensing optical cable 11. The anti-loosening fixing bolt 122 passes through the central through hole of the elastic stainless steel pressure plate 123 and forms a threaded connection with the threaded hole of the high-strength neodymium iron boron magnet 121. By tightening the anti-loosening fixing bolt 122, the clamping force of the elastic stainless steel pressure plate 123 can be adjusted, so that the distributed temperature sensing optical cable 11 forms a tight surface contact with the roller shaft surface, ensuring heat conduction efficiency and temperature measurement accuracy.

[0031] By precisely fixing the fixture 12, a one-to-one correspondence is achieved between each fiber grating in the weak reflection fiber grating array and the roller shaft of the entire belt conveyor, establishing a unique spatial mapping relationship between the fiber grating sensing point and the physical position of the roller on site, providing basic support for the accurate positioning of subsequent faulty rollers.

[0032] By leveraging the system's customized grating spacing design and one-to-one fixed deployment, precise temperature acquisition and fault location of the idler rollers are achieved. The customized, low-reflection fiber grating array ensures a perfect match between the sensing points and the idler roller installation positions, guaranteeing the authenticity and reliability of the temperature data. The unique spatial mapping relationship between the fiber grating and the idler roller shaft enables rapid location of faulty idlers, improving maintenance efficiency.

[0033] The optical signal collected by the sensing layer 1 is transmitted to the demodulation layer 2 for analysis and conversion. For example... Figure 1 As shown, demodulation layer 2 includes a weak-reflection fiber Bragg grating array demodulation device 21. This device 21 integrates dual-parameter demodulation functions for temperature and strain, and uses the principle of optical time-domain reflectometry to spatially locate temperature anomalies. During operation, the device 21 emits narrowband probe light pulses into the weak-reflection fiber Bragg grating array, receives reflected light signals from each fiber Bragg grating, identifies the spatial position of each fiber Bragg grating by the round-trip time difference of the reflected light, and calculates the real-time temperature of the corresponding idler roller by the center wavelength offset of the reflected light. Simultaneously, the demodulation device automatically identifies and filters invalid background light signals generated by the signal transmission fiber segment, avoiding redundant light signals from interfering with demodulation accuracy and further improving the accuracy and reliability of temperature monitoring.

[0034] The demodulated temperature data is uploaded to application layer 3 for unified management and intelligent analysis. For example... Figure 1 As shown, application layer 3 includes a map visualization module 31, a warning management module 32, and an analysis module 33, all loosely integrated through a standard API interface. The map visualization module 31 is built on a GIS geographic information system, supporting 2D / 3D map base map switching, real-time heat map rendering of the entire conveyor belt idler temperature, and playback of historical temperature trajectories, intuitively displaying the temperature distribution and evolution trend of the entire idler belt. The warning management module 32 supports multi-level alarm strategies, dynamically configuring different levels of temperature threshold parameters according to region, equipment type, and operating conditions, and supporting various warning methods such as audible and visual alarms, SMS push notifications, and platform pop-ups. The analysis module 33 adopts a hybrid architecture of time-series and relational databases. The time-series database stores frequently collected temperature time-series data, while the relational database stores structured data such as idler basic information and alarm records. The module has a built-in intelligent analysis engine that performs rolling predictions of idler temperature evolution trends based on historical temperature data, identifying potential thermal runaway risks in advance and realizing a shift from passive fault alarms to proactive prevention and early warning.

[0035] This invention also discloses a method for monitoring and early warning of fiber optic grating temperature on belt conveyor idler rollers. This method is implemented based on the aforementioned belt conveyor idler roller fiber optic grating temperature monitoring and early warning system, and the specific steps are as follows: Figure 3 As shown: S1. Conduct on-site surveys of the actual spacing and installation position of the idlers along the entire belt conveyor line. Based on the survey data, customize and inscribe a weak reflection fiber grating array to ensure that the spacing between adjacent fiber gratings in the array is completely consistent with the spacing between the idler roller shafts, thus completing the prefabrication of the distributed temperature sensing optical cable 11. S2. The prefabricated distributed temperature sensing optical cable 11 is continuously laid along the axial direction of the belt conveyor idler roller shaft. The distributed temperature sensing optical cable 11 is tightly attached and fixed to the surface of each idler roller shaft by multiple sets of fixing clamps 12, ensuring that each fiber grating is aligned with the center position of the corresponding idler roller shaft, and establishing a unique spatial correspondence between the fiber grating number and the physical position of the idler roller. S3. Start the weak reflection fiber grating array demodulation device 21, send narrowband probe light pulses to the weak reflection fiber grating array, receive the reflected light signals returned by each fiber grating based on the optical time domain reflection principle, calibrate the spatial position of each fiber grating by the time difference of the reflected light, calculate the real-time temperature of the corresponding idler roller by the wavelength offset of the reflected light, and automatically filter invalid background light signals generated by the signal transmission fiber segment. S4. Application Layer 3 receives temperature data transmitted from Demodulation Layer 2, establishes a mapping table linking the physical location of the idler roller, the fiber optic grating number, and the real-time temperature data, and compares the temperature data of all idler rollers on the line with the preset grade thresholds in real time. When the temperature of a single idler roller exceeds the first-level warning threshold, a first-level warning message is output and the precise location of the idler roller is displayed. When multiple adjacent idler rollers are detected to have synchronously abnormal temperatures or a single idler roller temperature exceeds the second-level alarm threshold, a second-level emergency alarm message is output and the relevant safety management system is activated to notify maintenance personnel to handle the situation promptly.

[0036] This method breaks away from the conventional process of fiber Bragg grating temperature measurement, which involves "deploying standard-specification optical cables on-site and then manually calibrating the sensor positions." Instead, it establishes an integrated implementation process of "on-site survey - customized marking - precise deployment - dual-dimensional calibration." During the physical installation phase, a one-to-one correspondence between the fiber Bragg gratings and the roller shafts is achieved using fixing clamps. In the signal demodulation phase, the spatial position of each fiber Bragg grating is calibrated a second time using the principle of optical time-domain reflectometry, forming a dual verification mechanism of physical alignment and optical calibration to eliminate positional offset errors generated during installation. Simultaneously, the demodulation equipment filters invalid background light signals and dynamically updates the sensor position mapping table during signal processing. When the rollers are replaced or the optical cable is partially shifted on-site, only one optical calibration is required to complete the system calibration, eliminating the need to redeploy the entire sensor cable.

[0037] Finally, it should be noted that this method addresses the needs of large-scale deployment and long-term stable operation in industrial settings by constructing a comprehensive engineering adaptation system to achieve seamless integration with existing belt conveyor management systems and low-cost implementation. The system connects to belt conveyor frequency converters, belt scales, and environmental monitoring terminals via standard Modbus and OPCUA protocols to acquire real-time operating parameters such as conveyor load rate, operating speed, and ambient temperature along the conveyor line. Based on these parameters, a dynamic threshold self-calibration model is constructed to replace the fixed threshold discrimination logic. For typical industrial conditions such as heavy-load start-up, material impact, and seasonal temperature differences, 12 standard operating condition templates are preset. Each template corresponds to an independent temperature threshold, temperature rise rate threshold, and adjacent idler roller temperature gradient threshold. The system automatically switches the corresponding discrimination parameters according to the real-time operating conditions.

[0038] At the engineering implementation level, a rapid deployment mode is adopted, combining prefabricated distributed temperature sensing optical cables with standardized fixing clamps. After the distributed temperature sensing optical cables have completed customized writing and full-link performance pre-testing in the factory, on-site installation only requires continuous laying along the roller axis using standardized fixing clamps. The deployment time per kilometer of conveyor does not exceed 8 hours, and no hot work is required throughout the process, making it suitable for special construction requirements such as underground and explosion-proof areas. During the operation and maintenance phase, the system supports online self-diagnosis and local section calibration functions. When a single roller is replaced or the optical cable is partially moved, there is no need to shut down the entire line. Only the optical calibration command for the corresponding section needs to be triggered in the central control room, and the system automatically completes the update of the sensor point mapping table, with a calibration time of no more than 30 seconds. Meanwhile, the system reserves standardized data interfaces, which can be directly connected to the enterprise's existing DCS, SCADA and safety production management platform. Early warning information is pushed to the central control operation interface, mobile operation and maintenance terminal and on-site sound and light alarm devices in a synchronized manner. It can also be linked with safety control systems such as belt conveyor emergency stop and automatic sprinkler system to form a closed-loop safety control process of monitoring-early warning-handling.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fiber optic grating temperature monitoring and early warning system for belt conveyor idler rollers, comprising a sensing layer, a demodulation layer, and an application layer; wherein the sensing layer, the demodulation layer, and the application layer are sequentially connected and work together to respectively realize the acquisition, signal demodulation, and early warning of belt conveyor idler roller temperature; Its features are, The sensing layer includes a distributed temperature sensing optical cable and a fixing clamp; the distributed temperature sensing optical cable includes a weak reflection fiber grating array; the sensing unit of the weak reflection fiber grating array is a fiber grating, the middle section is a signal transmission optical fiber, and the spacing of the fiber gratings is consistent with the spacing of the belt conveyor idler roller shafts; the fixing clamp attaches the distributed temperature sensing optical cable to the surface of the belt conveyor idler roller shafts, and each fiber grating corresponds one-to-one with the belt conveyor idler roller shaft.

2. The fiber optic grating temperature monitoring and early warning system for belt conveyor idlers according to claim 1, characterized in that, The distributed temperature sensing optical cable also includes an elastic sensitizing element and an armored sheath; the weak reflection fiber grating array, the elastic sensitizing element and the armored sheath are arranged coaxially from the inside to the outside.

3. The fiber optic grating temperature monitoring and early warning system for belt conveyor idlers according to claim 2, characterized in that, The elastic sensitizing element is attached to the fiber grating in a one-to-one correspondence and with matching length; the elastic sensitizing element amplifies the wavelength drift of the fiber grating through the thermal expansion coefficient matching effect, and isolates the axial and radial mechanical strain generated by the operation of the belt conveyor.

4. The fiber optic grating temperature monitoring and early warning system for belt conveyor idlers according to claim 3, characterized in that, The elastic sensitizing element adopts a segmented structure, including multiple slotted metal strips; each slotted metal strip corresponds to one fiber grating and has an equal length; the slotted metal strip is made of aluminum or copper.

5. The fiber optic grating temperature monitoring and early warning system for belt conveyor idlers according to claim 2, characterized in that, The armor sheath is a composite structure of a stainless steel braided layer and a flame-retardant polyolefin outer sheath; the stainless steel braided layer wraps around the outside of the elastic sensitive element; the flame-retardant polyolefin outer sheath wraps around the outside of the stainless steel braided layer.

6. The fiber optic grating temperature monitoring and early warning system for belt conveyor idlers according to claim 1, characterized in that, The fixing fixture includes a high-strength neodymium iron boron magnet, an anti-loosening fixing bolt, and an elastic stainless steel pressure plate; the high-strength neodymium iron boron magnet is attracted to the belt conveyor roller bracket or metal frame, and the attraction force is not less than 80N; the elastic stainless steel pressure plate is arc-shaped, and its inner arc surface holds the distributed temperature sensing optical cable; the anti-loosening fixing bolt passes through the elastic stainless steel pressure plate and is threadedly connected to the high-strength neodymium iron boron magnet.

7. The fiber optic grating temperature monitoring and early warning system for belt conveyor idlers according to claim 1, characterized in that, The demodulation layer includes a weak reflection fiber grating array demodulation device; the weak reflection fiber grating array demodulation device integrates temperature and strain dual-parameter demodulation functions, and realizes spatial positioning of temperature anomalies based on the principle of optical time-domain reflection.

8. The fiber optic grating temperature monitoring and early warning system for belt conveyor idlers according to claim 1, characterized in that, The application layer includes a map visualization module, a warning management module, and a data storage and analysis module, which are loosely integrated through a standard API interface.

9. The fiber optic grating temperature monitoring and early warning system for belt conveyor idlers according to claim 8, characterized in that, The map visualization module is based on a GIS geographic information system and supports switching between 2D / 3D map base maps, real-time heat map rendering, and playback of historical temperature trajectories. The warning management module supports multi-level alarm strategies and dynamically configures threshold parameters according to region, equipment type, and operating conditions. The data storage and analysis module adopts a hybrid architecture of time-series database and relational database, with a built-in intelligent analysis engine to perform rolling predictions of temperature evolution trends and identify potential thermal runaway risks.

10. A temperature monitoring and early warning method, characterized in that, Implemented by means of the fiber optic grating temperature monitoring and early warning system for belt conveyor idler rollers as described in any one of claims 1-9; The temperature monitoring and early warning method includes the following steps: S1. Based on the actual arrangement spacing of the idlers along the entire belt conveyor, pre-write the weak reflection fiber grating array whose fiber grating spacing is completely consistent with the idler roller shaft spacing. S2. The distributed temperature sensing optical cable integrating the weak reflection fiber grating array is continuously laid along the roller shaft axis. The fixed clamp is used to make the distributed temperature sensing optical cable form a surface contact with the surface of each roller shaft, and a unique spatial correspondence between each fiber grating and the roller shaft is established. S3. The demodulation layer emits narrowband probe light pulses to the weakly reflective fiber Bragg grating array, receives the reflected light signals returned by each fiber Bragg grating based on the principle of optical time-domain reflection, identifies the spatial position of each fiber Bragg grating by the time difference of the reflected light, calculates the real-time temperature of the corresponding roller by the wavelength offset of the reflected light, and filters out invalid light signals from each signal transmission fiber. S4. The application layer establishes an association mapping table of idler position - fiber optic grating number - temperature data, and compares the temperature data of all idlers on the belt conveyor with the preset threshold in real time. When the temperature of a single idler exceeds the first-level threshold or the temperature of multiple adjacent idlers is synchronously abnormal, the corresponding level of warning information is output, and the precise location of the abnormal idler is displayed simultaneously.

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