Mining laser dust concentration sensor based on the principle of light scattering

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Coal is a pillar industry for the development of China’s national economy. When it comes to the threats faced by coal mines, terms such as \"gas explosions,\" \"water inrush,\" and \"collapses\" come to mind. In fact, behind these disasters, there is another very dangerous threat: dust. During the mining, transportation, and processing of coal, large amounts of dust are generated. Excessively high dust concentrations can pose a risk of explosions, especially those caused by gas explosions in combination with dust explosions. Rising dust levels threaten the health of workers in coal mines; from the perspective of safe production, it is essential to monitor and control dust levels in coal mine environments in order to ensure safe operations. Current instruments for dust monitoring include dust samplers, dust meters, and dust concentration sensors. To measure the dust concentration in existing coal mine monitoring wells, the principle of laser scattering is utilized (the scattering of light refers to the phenomenon whereby part of the light deviates from its original path as it passes through a non-uniform medium). Light that deviates from its original direction is called scattered light. The high-tech sensors developed can monitor and display the dust concentration underground in real time, on-site, and continuously under natural airflow conditions; at the same time, they output digital signals related to the operation of dust suppression devices such as sprinklers, thereby achieving the best results for dust detection and suppression. The Laser Dust Sensor, Dust Sensor PM2.5 – DL0001, is a digital, general-purpose particle concentration sensor based on the principle of laser scattering; it can detect the concentration of suspended particles of various sizes in the air, including PM2.5. This sensor uses a laser diode as the light source, which shines on the suspended particles in the air to cause scattering; simultaneously, a photodetector is used to collect the scattered light. The scattered light collected generates a current signal due to the photoelectric effect; after being amplified and processed by electronic circuits, the concentration of particulate matter can be determined. This value is then converted into a mass concentration (μg/m3) using an algorithm based on the Mie theory, via a microprocessor, and is output in the form of a standard digital interface.