METHODS AND ALGORITHMS FOR MONITORING THE STATE OF THE GAS DIFFUSION FILTER OF METHANE ANALYZERS

"The results of research aimed at improving the reliability of stationary gas analyzers of gas protection systems are given. It is shown that it is possible to identify cases of contamination of the gas diffusion filter in methane analyzers, which can significantly affect the results of methane concentration measurement and lead to the failure of the protective shutdown system in the event of a danger of explosion, by analyzing the transient processes that occur in the analyzer after a short-term decrease in current through thermocouples of the sensor to the value at which the process of methane oxidation on the sensitive element stops. It is shown that in a thermocatalytic sensor with a double diffusion filter, when its filter element is significantly contaminated, the ratio of the amplitude of the bridge output voltage surge after a short-term decrease in current through the thermoelements to the value at which the methane oxidation process stops (after the pause) to the initial value of the bridge output voltage (before the pause) significantly increases, which makes it possible to detect pollution cases by analyzing the change in this ratio. The process of detecting significant pollution of the gas diffusion filter can be combined with the previously proposed process of automatic remote control of zero readings of the analyzers, which is carried out by reducing the power supply voltage of the thermogroup to the value at which the methane oxidation reaction does not occur on the working thermocouple. The method of detecting dangerous contamination of the gas diffusion filter is substantiated and the algorithm of operation of the ATmega8 microcontroller based on which the methane analyzer is implemented is described. "