METHOD OF MONITORING CHANGES IN INTEGRAL GAS MEDIUM COMPOSITION Russian patent published in 2016 - IPC G01N22/00 E21F17/00 A62B15/00 

FIELD: mining.

SUBSTANCE: one of the main tasks for providing safety of works in coal mines is monitoring the content of dangerous gases and mixtures in the mine atmosphere, among which the highest threats are methane and coal dust. Proposed method relates to electrical measurements and can be used for monitoring a change in the composition of integral gas medium in coal mines, in systems for monitoring exhaust gases released as the result of human industrial activities, or in similar complex systems, where there is the critical task of monitoring the concentration of secondary explosion and fire hazardous products. Monitoring changes of the integral gas medium is based on measuring changes in phase progression of a microwave signal at its multiple propagation along a closed waveguide structure, through which ambient air is also passed. By adjusting both total length of the waveguide structure serving as the measuring route and tuning frequency of the band-pass low-frequency filter identifying an informational low-frequency signal it is possible to obtain various sensitivity of the system as a whole. As per the proposed method it is a variable parameter. This allows performing common calibration relative to a certain type of controlled substance with a known value of its dielectric permeability, for example, inflammable, explosive and/or toxic gases. Owing to the use of the waveguide structure, inside which an ambient air flow circulates, the need to use additional repeaters remote from the measurement unit is completely excluded. Accuracy of measuring changes of the integral air composition operating as per the proposed method is high and in general case it will be directly proportional to the number of cycles of microwave oscillations passes inside the waveguide structure of a known length.

EFFECT: system built and functioning as per the proposed method is a complete functional unit, the need for spatial division of the system elements herewith with is absent, and, in contrast to short-lived thermochemical, expensive optical, catalytic and other gas analyzers, is resistant to dust and contaminants.

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