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Abstract: The mining laser dust sensor is developed based on the light scattering principle. It features high detection accuracy, a long service life, and stable, reliable performance, particularly in nonlinear signal processing and signal filtering. It possesses outstanding characteristics, and the sensor's design scheme is elaborated in detail.
Coal is a pillar industry for the development of the national economy in China. As a non-renewable resource, coal accounts for 70% of the primary energy structure. Coal mine production safety issues encompass many aspects. From a monitoring perspective, major gases such as carbon monoxide, carbon dioxide, and other hazardous substances can exceed limits, leading to gas explosions, poisoning incidents, and dust explosions caused by excessive dust concentrations during and after gas explosions. While coal mines currently have comprehensive equipment for monitoring underground hazardous gases, the effectiveness of existing equipment in monitoring dust concentration remains inadequate.
A large amount of coal and rock dust is generated during the mining and transportation of coal. With the increasing mechanization and mining intensity of coal mines, both dust production and concentration have risen significantly as coal production increases. The rise in dust concentration has caused significant harm to the health and safety of coal mine workers. From a health perspective, long-term exposure to a dust-polluted environment can lead to pneumoconiosis, seriously endangering workers' health. From a safety perspective, excessive dust concentration can lead to dust explosions, particularly those triggered by gas explosions, escalating the danger and causing greater harm. In response to these issues, extensive research has been conducted worldwide on monitoring and preventing underground dust in coal mines. Currently, the main types of dust monitoring instruments include dust samplers, dust meters, and dust concentration sensors.
The measurement cycle of dust samplers is long, and their complex method cannot reflect real-time data promptly; however, the high accuracy of samplers is essential for calibrating dust meters and dust concentration sensors. Dust meters are generally portable devices that can monitor dust concentration in industrial and mining environments in real-time; however, they currently lack wireless capabilities, preventing the timely upload of monitoring data to the system. Dust concentration sensors provide continuous monitoring and can upload data to the system in real-time. They also detect and process changes in dust concentration promptly, effectively performing early warning and dust reduction functions. The dust concentration sensor, designed based on the principle of laser light scattering, features high reliability, long service life, and high precision. It is now being gradually promoted in coal mine safety monitoring, which is significant for production operations, worker safety, and environmental protection.
Coal is a pillar industry for the development of the national economy in China. As a non-renewable resource, coal accounts for 70% of the primary energy structure. Coal mine production safety issues encompass many aspects. From a monitoring perspective, major gases such as carbon monoxide, carbon dioxide, and other hazardous substances can exceed limits, leading to gas explosions, poisoning incidents, and dust explosions caused by excessive dust concentrations during and after gas explosions. While coal mines currently have comprehensive equipment for monitoring underground hazardous gases, the effectiveness of existing equipment in monitoring dust concentration remains inadequate.
A large amount of coal and rock dust is generated during the mining and transportation of coal. With the increasing mechanization and mining intensity of coal mines, both dust production and concentration have risen significantly as coal production increases. The rise in dust concentration has caused significant harm to the health and safety of coal mine workers. From a health perspective, long-term exposure to a dust-polluted environment can lead to pneumoconiosis, seriously endangering workers' health. From a safety perspective, excessive dust concentration can lead to dust explosions, particularly those triggered by gas explosions, escalating the danger and causing greater harm. In response to these issues, extensive research has been conducted worldwide on monitoring and preventing underground dust in coal mines. Currently, the main types of dust monitoring instruments include dust samplers, dust meters, and dust concentration sensors.
The measurement cycle of dust samplers is long, and their complex method cannot reflect real-time data promptly; however, the high accuracy of samplers is essential for calibrating dust meters and dust concentration sensors. Dust meters are generally portable devices that can monitor dust concentration in industrial and mining environments in real-time; however, they currently lack wireless capabilities, preventing the timely upload of monitoring data to the system. Dust concentration sensors provide continuous monitoring and can upload data to the system in real-time. They also detect and process changes in dust concentration promptly, effectively performing early warning and dust reduction functions. The dust concentration sensor, designed based on the principle of laser light scattering, features high reliability, long service life, and high precision. It is now being gradually promoted in coal mine safety monitoring, which is significant for production operations, worker safety, and environmental protection.
Overall Design Scheme
The dust concentration sensor consists mainly of the following components: a light emission signal control unit, a signal acquisition and processing unit, a main control function unit, and a dust collection unit.
The light emission signal control unit primarily consists of a current drive circuit and a laser light source. The current drive circuit provides a constant and regulated current for the laser light source, enabling it to emit continuous laser light, with the laser photons projected into the dust collection chamber through the front lens.
The dust collection unit primarily consists of a dust collection chamber and an air pump. Once the sensor is powered on, the air pump starts, creating negative pressure extraction. Dust continuously enters the collection chamber through the air inlet, forming a dust-laden airflow. The light emitted by the source is focused onto the dust flow through the focusing lens, and the scattered light is collected by the photodiode, sending the relevant dust concentration signal to the signal acquisition and processing unit.
The signal acquisition and processing unit primarily consists of a pre-processing circuit, a filter amplifier circuit, and a data acquisition circuit. The dust collection unit processes the received light scattering signal sequentially through the pre-processing circuit, where the light signal is converted into a current signal via the photodiode, and the current signal is further converted into a voltage signal by the operational circuit. The scattering signal is then filtered and amplified before being transmitted to the main control function unit through the data acquisition circuit.
The main control function unit primarily consists of a single-chip control unit, a communication transmission module (digital, frequency, wireless), a human-computer interaction module (display, control), and a monitoring host. The control chip receives the dust concentration signal, processes it, calculates the dust concentration in the current environment, and transmits the data to the monitoring host via the communication transmission module. The three data transmission modes—frequency, digital, and wireless—are combined, and the human-computer interaction module ensures efficient signal transmission through signal switching control. Additionally, the human-computer interaction module includes functions for display, alarm, and debugging. The entire detection process enables comprehensive monitoring of dust concentration.
The light emission signal control unit primarily consists of a current drive circuit and a laser light source. The current drive circuit provides a constant and regulated current for the laser light source, enabling it to emit continuous laser light, with the laser photons projected into the dust collection chamber through the front lens.
The dust collection unit primarily consists of a dust collection chamber and an air pump. Once the sensor is powered on, the air pump starts, creating negative pressure extraction. Dust continuously enters the collection chamber through the air inlet, forming a dust-laden airflow. The light emitted by the source is focused onto the dust flow through the focusing lens, and the scattered light is collected by the photodiode, sending the relevant dust concentration signal to the signal acquisition and processing unit.
The signal acquisition and processing unit primarily consists of a pre-processing circuit, a filter amplifier circuit, and a data acquisition circuit. The dust collection unit processes the received light scattering signal sequentially through the pre-processing circuit, where the light signal is converted into a current signal via the photodiode, and the current signal is further converted into a voltage signal by the operational circuit. The scattering signal is then filtered and amplified before being transmitted to the main control function unit through the data acquisition circuit.
The main control function unit primarily consists of a single-chip control unit, a communication transmission module (digital, frequency, wireless), a human-computer interaction module (display, control), and a monitoring host. The control chip receives the dust concentration signal, processes it, calculates the dust concentration in the current environment, and transmits the data to the monitoring host via the communication transmission module. The three data transmission modes—frequency, digital, and wireless—are combined, and the human-computer interaction module ensures efficient signal transmission through signal switching control. Additionally, the human-computer interaction module includes functions for display, alarm, and debugging. The entire detection process enables comprehensive monitoring of dust concentration.
Conclusion
The design scheme for the mine laser dust concentration sensor, based on the principle of light scattering, is explained in detail. The mine dust sensor, based on the principle of light scattering, offers more accurate and timely detection of coal mine dust concentration, while the high reliability and long lifespan of the laser will contribute to safer production and monitoring conditions. The mine laser dust sensor offers a more convenient, efficient, and accurate method for detecting dust in coal mines.
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