METHOD OF MEASURING GAS CONCENTRATION BY A CATALYTIC SENSOR Russian patent published in 2019 - IPC G01N27/12 

FIELD: measuring equipment.

SUBSTANCE: invention relates to measurement equipment and can be used in gas analysers of combustible gases. Method of measuring gas concentration by a catalytic sensor consists of heating to a given temperature of a heater sensitive sensor element, which is simultaneously a resistance thermometer, electric pulses, controlling the duty cycle of which is carried out using PWM generator, wherein temperature of heater is stabilized by feeding to feedback input PWM generator value of amplitude drop of voltage on heater, which is proportional to its resistance, depending on temperature, wherein heater is heated by current pulses of stable voltage source, flowing through heater and series-connected reference resistor, stabilizing resistance of heater by changing ratio of pulse duration to period T_PUL/T_PERIOD (filling factor) in the control signal supplied from the output of the program-controlled PWM generator, memorizing value of filling factor, at that coefficient of filling is determined for two values of temperature – working, at which reaction of catalytic oxidation takes place, and reduced, at which reaction does not flow, and the pulse duration value is used to compensate for the ambient temperature variation error, at that, informative parameter, which is proportional to power of analyte released during catalytic reaction and, consequently, concentration of analyte, is difference of control signal filling factor at working temperature of heater and duty ratio at lower temperature of heater, multiplied by a correction factor determined by a single calculation method as a product of voltage amplitudes on the heater and a reference resistor in a compensation mode divided by the product of the same voltages in the operating mode, compensated by subtracting the value of the same difference but obtained in the absence of the analyte in single calibration.

EFFECT: reduced measurement errors related to ambient temperature fluctuations.

1 cl, 3 dwg