METHOD OF DETERMINING HYDROGEN CONCENTRATION IN PRESENCE OF GASEOUS IMPURITIES Russian patent published in 2009 - IPC G01N27/14 

FIELD: physics.

SUBSTANCE: method of determining hydrogen concentration in the presence of gaseous impurities involves measurement of an electrical signal at the output of a semiconductor sensor with a metal oxide sensitive layer while heating it to a given temperature. The value of conductivity of the sensitive layer of the semiconductor sensor is determined from the value of this signal, stored, compared with a calibration value and hydrogen concentration is determined. The signal at the output of the semiconductor sensor is continuously measured, while periodically heating the sensor to temperature T₁ and cooling to temperature T₂. The time derivative of the conductivity of the sensitive layer of the sensor is determined during the interval between the end of the heating to T₁ and the end of cooling to T₂. The value of conductivity, which is a function of gas concentration, is determined. Presence and number of local minimums on the graph of conductivity of the sensitive layer versus time in the interval between the end of heating and the end of cooling is then determined. If there are two local minimums, the electrical signal at the output of the semiconductor sensor is measured in the time interval between the first and last local minimums, in which the absolute value the time derivative of conductivity is minimal. If there is one local minimum, the electrical signal at the output of the semiconductor sensor is measured in the time interval between the end of heating and the last local minimum, in which the absolute value of the time derivative of conductivity is minimal, and from the value of the measured electrical signal, the value of conductivity of the sensitive layer of the semiconductor sensor is determined, from which hydrogen concentration is determined.

EFFECT: increased accuracy and selectivity of determining hydrogen concentration.

3 cl, 2 dwg