Ensuring Explosion Safety of the Mine Methane Flow Meter during Operation, as well as at Primary and Periodic Calibration
At the mines where hazardous and threatening with sudden outburst emissions coal seams are developed, it is required to conduct a current forecast of the coal seams outburst hazard, which is based on an estimate of methane consumption from the control drill holes. Previously, the gas flow rate was measured using PG2-MA and IG-1 pressure gauges. Pressure gauges have some significant drawbacks. Their capillaries are regularly clogged with coal dust coming out from the control drill hole, which results in distortion of the measurement results. Pressure gauges do not register measured flow rate values, they do not have compensation for temperature errors. Metrological support is developed for pressure gauges that reduces the forecast accuracy and reliability. For eliminating above shortcomings, the development of modern mine methane flow meters was conducted based on the hot-wire measurement principle with electronic processing of the measured information. Cross-sectional area of the flow meter primary sensor is dozens of times larger compared to the pressure gauges, therefore the coal dust does not clog the gas path. The temperature error is automatically corrected. High-speed response ensures recording the real dynamics of gas release from the control drill hole. Several additional service functions are implemented. For electronic flow meters, the metrological support is developed and certified in accordance with the established procedure, including a method for checking the device with clean air (instead of methane) and an exemplary installation. Due to special circuitry solutions, the explosion-proof design of the CoalAwakeningBeast device with the type of protection «intrinsically safe electrical circuit» is provided, which is confirmed by the results of testing the flowmeter in the laboratories of MakNII and VostNII. Industrial tests conducted at the mines in four coal-mining basins confirmed the functionality of the device. In the Karaganda Technical University based on the development of Scientific and technical producer's cooperative NTPK Microclim (Karaganda, Kazakhstan), preparations are being made for a small-scale production of CoalAwakeningBeast flow meters.