Fault voiceprint distributed optical fiber acoustic resonance enhancement monitoring device for belt conveyor
By improving fiber optic acoustic sensing technology and acoustic resonance structure, the problem of insufficient sensitivity in belt conveyor fault monitoring has been solved, enabling early warning and efficient monitoring of idler roller faults, and reducing production interruptions and maintenance costs.
Patent Information
- Application Number
- CN202511105261.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-07
- Publication Date
- 2025-11-14
AI Technical Summary
Existing technologies struggle to achieve highly sensitive distributed fault acoustic monitoring on belt conveyors, especially in complex field environments where it is difficult to identify weak fault signals. Traditional monitoring methods are inefficient and cannot comprehensively monitor the overall status.
By employing dual-channel distributed fiber optic acoustic wave sensing technology, designing an acoustic resonance structure and improving the laser structure, and deploying a pickup probe below the idler roller and above the quartz bracket, combined with an optical fiber fixing device, a resonant pickup probe is formed, which amplifies the acoustic wave signal and suppresses noise interference, thereby improving monitoring sensitivity.
It enables early warning of belt conveyor idler roller failures, can keenly detect weak fault signals, reduce production interruptions and maintenance costs, and improve system signal stability and detection sensitivity.
Smart Images
Figure CN120942858A_ABST
Abstract
Description
Technical Field
[0001] This invention provides a distributed fiber optic acoustic resonance enhancement monitoring device for belt conveyor fault acoustic signatures, belonging to the field of belt conveyor fault acoustic signature monitoring technology. Background Technology
[0002] Belt conveyors are widely used in mining, ports, power and other fields, and are key equipment for material transportation. During their long-term operation, various failures are prone to occur due to mechanical wear, material impact and component aging, such as conveyor belt tearing, idler damage and bearing jamming. These failures can not only lead to production interruption and increase maintenance costs, but may also cause safety accidents.
[0003] Currently, fault monitoring of belt conveyors mainly adopts traditional monitoring methods, such as manual inspection and monitoring based on vibration sensors or temperature sensors. However, manual inspection is inefficient, subjective, and difficult to detect early faults in real time. Traditional vibration sensors and temperature sensors can only perform point monitoring and cannot comprehensively monitor the overall condition of the belt conveyor.
[0004] With the development of fiber optic sensing technology, distributed fiber optic acoustic wave sensing technology has shown unique advantages in fields such as structural health monitoring. It features distributed measurement, high sensitivity, and resistance to electromagnetic interference, enabling real-time monitoring of acoustic wave signals distributed along optical fibers. However, in current applications of belt conveyor fault monitoring, the complex on-site environment, high background noise, and attenuation of the acoustic wave signals generated by the fault during propagation limit the detection sensitivity, making it difficult to accurately identify weak fault signals. Therefore, improving the current distributed fiber optic acoustic wave sensing system for conveyor fault monitoring by adding effective sound enhancement structures to enhance the acoustic detection effect of distributed fiber optic acoustic wave sensing in belt conveyor fault monitoring is of significant practical importance. Summary of the Invention
[0005] To address the technical problems existing in the background art, the present invention provides a distributed fiber optic acoustic resonance enhancement monitoring device for belt conveyor fault acoustic patterns, comprising a laser, a first pickup probe, a second pickup probe, and a computer. Inside the laser are arranged a circuit board, a pump source, a phase-shifting grating, a first wavelength division multiplexer, a first isolator, a second wavelength division multiplexer, an erbium-doped fiber, and a second isolator. The output of the circuit board is connected to the input of the pump source, the output of the pump source is connected to the input of the phase-shifting grating, the output of the phase-shifting grating is connected to the input port c of the first wavelength division multiplexer, the output port a of the first wavelength division multiplexer is connected to the input port a of the second wavelength division multiplexer, the output port b of the first wavelength division multiplexer is connected to the input port b of the second wavelength division multiplexer via the first isolator, the output port c of the second wavelength division multiplexer is connected to the input of the erbium-doped fiber, and the output of the erbium-doped fiber is connected to the input of the second isolator. The output of the second isolator is connected to the a input of the first fiber coupler as the output of the laser. The b output of the first fiber coupler is connected to the a input of the acousto-optic modulator. The c output of the first fiber coupler is connected to the a input of the third fiber coupler. The c-output terminal of the acousto-optic modulator is connected to the input terminal of the erbium-doped fiber amplifier, and the b-input terminal of the acousto-optic modulator is connected to the output terminal of the signal generator used to provide pulse signals. The output of the erbium-doped fiber amplifier is connected to the input of the dense wavelength division multiplexer, the output of the dense wavelength division multiplexer is connected to the input of the optical filter, and the output of the optical filter is connected to the a input of the second fiber coupler. The b-output terminal of the second fiber optic coupler is connected to the a-input terminal of the second circulator, and the c-output terminal of the second circulator is connected to the b-input terminal of the second photodetector. The c-output terminal of the second fiber optic coupler is connected to the a-input terminal of the first circulator, and the c-output terminal of the first circulator is connected to the b-input terminal of the first photodetector. The b-output terminal of the third fiber optic coupler is connected to the a-input terminal of the first photodetector; The c-output terminal of the third fiber optic coupler is connected to the a-input terminal of the second photodetector; The c output terminal of the first photodetector is connected to the a input terminal of the data acquisition card, the c output terminal of the second photodetector is connected to the b input terminal of the data acquisition card, and the c output terminal of the data acquisition card is connected to the input terminal of the computer. The first pickup probe is composed of a first sensing fiber, a first fiber fixing structure, a linear array resonant structure, and a third isolator, all encapsulated by a first acoustic encapsulation device. The second pickup probe is composed of a second sensing fiber, a second fiber fixing structure, a ring-converging resonant structure, and a fourth isolator, all encapsulated by a second acoustic encapsulation device. The output end b of the first circulator is connected to the input end of the first sensing fiber inside the first pickup probe. The first sensing fiber is fixed on the linear array resonant structure by the first fiber fixing structure. The output end of the first sensing fiber is connected to the input end of the third isolator. The output end b of the second circulator is connected to the input end of the second sensing fiber inside the second pickup probe. The second sensing fiber is laid on the ring resonant structure using the second fiber fixing structure. The output end of the second sensing fiber is connected to the input end of the fourth isolator.
[0006] Both the linear array resonance structure and the ring-converged resonance structure are composed of Mie resonance units.
[0007] The laser is specifically a 1550nm narrow linewidth laser.
[0008] The optical filter is specifically a 1550nm optical filter.
[0009] The present invention has the following advantages over the prior art: I. This invention employs dual-channel distributed fiber optic acoustic wave sensing technology to improve the fault acoustic signature monitoring scheme for belt conveyors. One of the sound pickup probes is positioned below the idler roller, directly contacting the conveyor. This allows for the sensitive detection of subtle vibration signals generated when the belt conveyor idler roller malfunctions, providing crucial evidence for early warning of idler roller mechanical failures. The other sound pickup probe is mounted above a quartz holder, avoiding direct contact with the conveyor and effectively preventing interference from mechanical contact. This installation structure can clearly monitor the acoustic signature signals radiated when the conveyor idler roller malfunctions. Furthermore, the quartz holder possesses excellent acoustic conduction and stability characteristics, ensuring the purity and stability of the acoustic signature signal acquisition.
[0010] Second, this invention introduces the principle of acoustic resonance. By designing and building an acoustic resonance structure, sound waves generate a strong resonance effect within a specific structure, amplifying the sound signal. Secondly, the sensing fiber is combined with the resonance structure through an optical fiber fixing device and then encapsulated to form a resonance pickup probe, which is used to monitor the subtle fault sounds of belt conveyor rollers. This improves the system's sensitivity to detecting belt conveyor fault sounds and can effectively detect early weak fault signals, such as the sound generated by slight wear of the rollers or small cracks in the conveyor belt. This provides a basis for early maintenance, reduces production interruptions caused by sudden failures, and lowers maintenance costs and economic losses.
[0011] Third, this invention improves the internal structure of the laser. The failure frequency of the belt conveyor roller is concentrated in the low frequency range. The monitoring device provided in this application is based on pump isolation, which can effectively isolate pump noise and optical feedback, prevent noise and fluctuations generated by the pump source from being fed back into the resonant cavity of the laser to amplify the frequency drift and phase noise of the laser, effectively suppress the frequency drift in the low frequency band, and ensure that the population inversion in the laser medium is in a relatively stable state through the effective coupling and power stabilization of the pump light by two wavelength division multiplexers. With reasonable component layout, heat can be better dissipated, which helps to improve the stability of the laser and improve the detection sensitivity of the system. Attached Figure Description
[0012] The present invention will be further described below with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of the distributed fiber optic acoustic resonance enhancement monitoring device for fault acoustic patterns in belt conveyors according to the present invention. Figure 2 This is a diagram illustrating the deployment effect of the monitoring device in an embodiment of the present invention. The meanings of the numbers in the diagram are as follows: 1 is a circuit board, 2 is a pump source, 3 is a phase-shifting grating, 4 is the first wavelength division multiplexer, 5 is the first isolator, 6 is the second wavelength division multiplexer, 7 is erbium-doped fiber, 8 is the second isolator, 9 is the first fiber coupler, 10 is an acousto-optic modulator, 11 is a signal generator, 12 is an erbium-doped fiber amplifier, 13 is a dense wavelength division multiplexer, 14 is an optical filter, 15 is the second fiber coupler, 16 is the first circulator, 17 is the second circulator, 18 is the first sensing fiber, and 19 is the first fiber fixing structure. 20 is a linear array resonant structure, 21 is a third isolator, 22 is a first acoustic encapsulation device, 23 is a second sensing fiber, 24 is a second fiber fixing structure, 25 is a ring-converged resonant structure, 26 is a fourth isolator, 27 is a second acoustic encapsulation device, 28 is a third fiber coupler, 29 is a first photodetector, 30 is a second photodetector, 31 is a data acquisition card, 32 is a computer, 33 is a laser, 34 is a first sound pickup probe, 35 is a second sound pickup probe, and 36 is a Mie resonant unit. Detailed Implementation
[0013] This invention provides a distributed fiber optic acoustic resonance enhancement monitoring device for belt conveyor faults. Its purpose is to overcome the shortcomings of insufficient sensitivity of existing distributed fiber optic acoustic wave sensing technology in belt conveyor fault monitoring by improving the internal structure of traditional lasers in the optical path system and designing sound enhancement structures.
[0014] This invention effectively reduces the phase noise and low-frequency drift of the laser by optimizing the laser optical path design and component layout, thereby significantly improving the signal stability and detection sensitivity of the system. Simultaneously, a sound enhancement structure is designed, and through a special acoustic resonance design, it can effectively amplify the weak fault acoustic signals generated during the operation of the belt conveyor, further enhancing the acoustic monitoring capability of the system. This invention deploys fiber optic pickup probes under the belt conveyor rollers and on a pre-built quartz support. By detecting the beat frequency of the pulsed light signal and the original laser signal, it enhances the detection of fault acoustic signals of the belt conveyor. A photodetector receives the beat frequency signals from each channel, converts them, processes them in the system, and issues an alarm for the fault signal, achieving timely capture and accurate identification of mechanical fault signals of the conveyor.
[0015] like Figure 1 As shown, the distributed fiber acoustic resonance enhancement monitoring device for fault acoustic patterns of belt conveyors provided by the present invention includes a laser 33 consisting of a circuit board 1, a pump source 2, a phase shift grating 3, a first wavelength division multiplexer 4, a first isolator 5, a second wavelength division multiplexer 6, an erbium-doped fiber 7, and a second isolator 8. It also includes a first fiber coupler 9, an acousto-optic modulator 10, a signal generator 11, an erbium-doped fiber amplifier 12, a dense wavelength division multiplexer 13, an optical filter 14, and a second fiber coupler 15; It also includes a first circulator 16, a second circulator 17, a third fiber optic coupler 28, a first photodetector 29, a second photodetector 30, a data acquisition card 31, and a computer 32; It also includes a first pickup probe 34 and a second pickup probe 35, wherein: The first pickup probe 34 is formed by encapsulating the first sensing fiber 18, the first fiber fixing structure 19, the linear array resonant structure 20 and the third isolator 21 through the first acoustic encapsulation device 22. The second pickup probe 35 is formed by encapsulating the second sensing fiber 23, the second fiber fixing structure 24, the ring resonant structure 25 and the fourth isolator 26 through the second acoustic encapsulation device 27.
[0016] The linear array resonance structure 20 and the ring-shaped resonance structure 25 are both composed of Mie resonance units 36.
[0017] Figure 2 This is a diagram illustrating the layout of the monitoring device in an embodiment of the present invention. It shows the positions and methods for deploying the first sound pickup probe 34 and the second sound pickup probe 35 on a belt conveyor. The sound pickup probes are all composed of a combination of sensing optical fiber and a resonance device. The resonance device is composed of several Mie resonance units 36 arranged in a certain manner. The resonance principle is used to enhance the sound signal, thereby greatly improving the detection sensitivity of the system.
[0018] The following is combined with Figure 1 and Figure 2 Specific embodiments of the present invention are described below: In laser 33, the output port of circuit board 1 is connected to the input port of pump source 2, controlling the pump source to emit a 980nm wavelength pump light to provide energy to the gain medium. The output port of pump source 2 is connected to the input port of phase shift grating 3, enabling it to perform frequency selection and feedback, generating high reflectivity for light of a specific wavelength, allowing light meeting specific wavelength conditions to travel back and forth multiple times within the resonant cavity and be continuously amplified. The output port of phase shift grating 3 is connected to port c of the first wavelength division multiplexer 4; port a of the first wavelength division multiplexer 4 is connected to port a of the second wavelength division multiplexer 6, and port b of the first wavelength division multiplexer 4 is connected to port b of the second wavelength division multiplexer 6 via the first isolator 5. Through the combination of the two wavelength division multiplexers, light of different wavelengths is combined and demultiplexed, and the 980nm pump light is coupled into the erbium-doped fiber, while the 1550nm laser generated in the laser resonant cavity can be output. The c-port of the second wavelength division multiplexer 6 is connected to the input of the erbium-doped fiber 7, which serves as the gain medium for the laser. Under the excitation of 980nm pump light, erbium ions in the erbium-doped fiber transition from the ground state to the excited state, generating laser light near 1550nm. The output of the erbium-doped fiber 7 is connected to the input of the second isolator 8 to prevent reflected light from affecting the narrow-linewidth laser. The output of the second isolator 8 serves as the output of the laser 33. The improved 1550nm narrow-linewidth laser 33 reduces its own frequency drift and phase noise, thereby improving the system's detection sensitivity.
[0019] The laser 33 emits a continuous narrow-linewidth laser with a center wavelength of 1550nm, which is input to the a input terminal of the first fiber coupler 9. The first fiber coupler 9 divides the laser into two parts: 80% and 20%. The 80% laser is output as probe light from the b port of the first fiber coupler 9, and the 20% laser is output as local light from the c port of the first fiber coupler 9 to the a input terminal of the third fiber coupler 28. The probe light output from the b port of the first fiber coupler 9 is input to the a input terminal of the acousto-optic modulator 10. The signal generator 11 is connected to the b input terminal of the acousto-optic modulator 10 and provides it with a periodically alternating high and low peak power pulse signal. Driven by the signal generator 11, the acousto-optic modulator 10 modulates the continuous probe light into pulsed light and generates a 200MHz frequency shift. The modulated pulsed light is output from the c output terminal of the acousto-optic modulator 10 to the input terminal of the erbium-doped fiber amplifier 12. The amplified pulsed light signal is input to the input terminal of the dense wavelength division multiplexer 13 for subsequent transmission. The pulsed light signal is input from the output terminal of the dense wavelength division multiplexer 13 to the input terminal of the 1550nm optical filter 14 for filtering. The filtered 1550nm optical signal is sent to the a input terminal of the second fiber coupler 15 and divided into two parts of optical signal, 50% and 50%, which are then detected by optical fiber.
[0020] The c-output terminal of the second fiber optic coupler 15 is connected to the a-input terminal of the first circulator 16; the first sensing fiber 18 is laid on the linear array resonant structure 20 via the first fiber fixing structure 19; the output terminal of the first sensing fiber 18 is connected to the input terminal of the third isolator 21; the first sensing fiber 18, the first fiber fixing structure 19, the linear array resonant structure 20, and the third isolator 21 are packaged into a first pickup probe 34 by the first acoustic packaging device 22; the b-output terminal of the first circulator 16 is connected to the first pickup probe 34 to improve the pickup sensitivity of the device. The b-output terminal of the second fiber optic coupler 15 is connected to the a-input terminal of the second circulator 17; the second sensing fiber optic cable 23 is laid on the ring-converging resonant structure 25 via the second fiber optic fixing structure 24; the output terminal of the second sensing fiber optic cable 23 is connected to the input terminal of the fourth isolator 26; the second sensing fiber optic cable 23, the second fiber optic fixing structure 24, the ring-converging resonant structure 25, and the fourth isolator 26 are packaged into a second acoustic pickup probe 35 via a second acoustic encapsulation device 27; the b-output terminal of the second circulator 17 is connected to the second pickup probe 35 to improve the pickup sensitivity of the device. Utilizing the non-reciprocity of the circulator ensures effective signal transmission and processing in the pickup probe, thereby enhancing the monitoring capability of vibration and acoustic signature signals.
[0021] like Figure 2As shown, the Mie resonant unit 36 is columnar with N=4 folds to enhance the low-frequency sound wave resonance effect. The linear array resonant structure 20 is composed of six Mie resonant units arranged in an array spaced 0.5m apart, which can focus the sound wave signal energy around the array, increase the area for capturing resonant frequency signals, and improve the receiving sensitivity; the first sensing fiber 18 is deployed on the linear array resonant structure 20 through the first fiber fixing structure 19. After being encapsulated by the first acoustic encapsulation device 22, it forms a first pickup probe 34 with the first sensing fiber 18 and is deployed on the linear array resonant structure 20. Figure 2 The second sensing fiber optic cable 23 is positioned below the conveyor rollers in the ring, thereby improving the system's detection sensitivity. The ring-shaped resonant structure 25 consists of six Mie resonant units spaced 0.2m apart in a regular hexagonal arrangement, with the central region serving as the sound focusing area, which can significantly amplify sound waves within the resonant frequency range. The second sensing fiber optic cable 23 is positioned at the center of the ring-shaped resonant structure 25 to sense the sound wave signal in the sound focusing area. After being encapsulated by the second acoustic encapsulation device 27, it works in conjunction with the second sensing fiber optic cable 23 to form a second pickup probe 35, which is mounted above the quartz support.
[0022] The b-output terminal of the third fiber optic coupler 28 is connected to the a-input terminal of the first photodetector 29; the c-output terminal of the first circulator 16 is connected to the b-input terminal of the first photodetector 29; the c-output terminal of the third fiber optic coupler 28 is connected to the a-input terminal of the second photodetector 30; and the c-output terminal of the second circulator 17 is connected to the b-input terminal of the second photodetector 30. The first photodetector 29 and the second photodetector 30 coherently superimpose the two optical signals and then convert them into electrical signals for subsequent processing such as amplification and demodulation. The c-output terminal of the first photodetector 29 is connected to the a-input terminal of the acquisition card 31, and the c-output terminal of the second photodetector 30 is connected to the b-input terminal of the acquisition card 31. The acquisition card 31 acquires the analog electrical signals at a certain sampling frequency and converts them into digital signals that can be processed by a computer. The C output terminal of the acquisition card 31 is connected to the input terminal of the computer 32. The computer 32 processes and analyzes the acquired data through the host computer software and displays it on the computer screen in an intuitive way, such as displaying the change of the belt conveyor sound signal over time in the form of a waveform graph, or presenting the frequency distribution of the signal in the form of a spectrum graph. Technicians can observe the dynamic changes of the belt conveyor sound in real time and intuitively understand its operating status.
[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A distributed fiber optic acoustic resonance enhancement monitoring device for fault acoustic patterns in belt conveyors, comprising a laser (33), a first acoustic pickup probe (34), a second acoustic pickup probe (35), and a computer (32), characterized in that: Inside the laser (33) are arranged a circuit board (1), a pump source (2), a phase shift grating (3), a first wavelength division multiplexer (4), a first isolator (5), a second wavelength division multiplexer (6), an erbium-doped fiber (7), and a second isolator (8). The output end of the circuit board (1) is connected to the input end of the pump source (2), the output end of the pump source (2) is connected to the input end of the phase shift grating (3), the output end of the phase shift grating (3) is connected to the input c port of the first wavelength division multiplexer (4), the output a port of the first wavelength division multiplexer (4) is connected to the input a port of the second wavelength division multiplexer (6), the output b port of the first wavelength division multiplexer (4) is connected to the input b port of the second wavelength division multiplexer (6) via the first isolator (5), the output c port of the second wavelength division multiplexer (6) is connected to the input end of the erbium-doped fiber (7), and the output end of the erbium-doped fiber (7) is connected to the input end of the second isolator (8). The output of the second isolator (8) is connected to the a input of the first fiber coupler (9) as the output of the laser (33), the b output of the first fiber coupler (9) is connected to the a input of the acousto-optic modulator (10), and the c output of the first fiber coupler (9) is connected to the a input of the third fiber coupler (28). The c output terminal of the acousto-optic modulator (10) is connected to the input terminal of the erbium-doped fiber amplifier (12), and the b input terminal of the acousto-optic modulator (10) is connected to the output terminal of the signal generator (11) used to provide pulse signals. The output of the erbium-doped fiber amplifier (12) is connected to the input of the dense wavelength division multiplexer (13), the output of the dense wavelength division multiplexer (13) is connected to the input of the optical filter (14), and the output of the optical filter (14) is connected to the a input of the second fiber coupler (15). The b output terminal of the second fiber coupler (15) is connected to the a input terminal of the second circulator (17), and the c output terminal of the second circulator (17) is connected to the b input terminal of the second photodetector (30). The c output terminal of the second fiber coupler (15) is connected to the a input terminal of the first circulator (16), and the c output terminal of the first circulator (16) is connected to the b input terminal of the first photodetector (29). The b output terminal of the third fiber optic coupler (28) is connected to the a input terminal of the first photodetector (29); The c-output terminal of the third fiber optic coupler (28) is connected to the a-input terminal of the second photodetector (30); The c output terminal of the first photodetector (29) is connected to the a input terminal of the acquisition card (31), the c output terminal of the second photodetector (30) is connected to the b input terminal of the acquisition card (31), and the c output terminal of the acquisition card (31) is connected to the input terminal of the computer (32). The first pickup probe (34) is formed by encapsulating the first sensing fiber (18), the first fiber fixing structure (19), the linear array resonant structure (20), and the third isolator (21) through the first acoustic encapsulation device (22); The second pickup probe (35) is formed by encapsulating the second sensing fiber (23), the second fiber fixing structure (24), the ring resonant structure (25), and the fourth isolator (26) through the second acoustic encapsulation device (27); The b output end of the first circulator (16) is connected to the input end of the first sensing fiber (18) inside the first pickup probe (34). The first sensing fiber (18) is fixed on the linear array resonant structure (20) by the first fiber fixing structure (19). The output end of the first sensing fiber (18) is connected to the input end of the third isolator (21). The output end of the second circulator (17) is connected to the input end of the second sensing fiber (23) inside the second pickup probe (35). The second sensing fiber (23) is laid on the ring resonant structure (25) by the second fiber fixing structure (24). The output end of the second sensing fiber (23) is connected to the input end of the fourth isolator (26).
2. The distributed fiber optic acoustic resonance enhancement monitoring device for belt conveyor fault acoustic patterns according to claim 1, characterized in that: Both the linear array resonance structure (20) and the annular resonance structure (25) are composed of Mie resonance units (36).
3. The distributed fiber optic acoustic resonance enhancement monitoring device for belt conveyor fault acoustic patterns according to claim 1, characterized in that: The laser (33) is specifically a 1550nm narrow linewidth laser.
4. The distributed fiber optic acoustic resonance enhancement monitoring device for fault acoustic patterns of belt conveyors according to claim 1, characterized in that: The optical filter (14) is specifically a 1550nm optical filter.