Elichens

Other

Thanh Trung Le

Hélène Duprez

Method for measuring an amount of a gas species—able to absorb light in an absorption spectral band—includes placing a gas between a measurement photodetector and a light source able to emit an incident light wave propagating through the gas to the photodetector. Electrical supply current passes through the light source to bring it to a temperature value. At multiple times: the light source illuminates the gas; the measurement photodetector measures a 'measurement' intensity of a light wave transmitted by the gas in a measurement spectral band; and a reference photodetector measures a “reference” intensity of a reference light wave emitted by the light source in a reference spectral band. At each measurement time, a correction function—representative of a variation in the incident light wave's intensity in the measurement band relative to in the reference spectral band—is taken into account based on the measured reference intensity.

Method for analysing a gas using an optical sensor

A method for measuring an amount of a gaseous species present in a gas, the gaseous species absorbing light in an absorption spectral band, comprises placing the gas between a light source and a measuring photodetector. The light source is configured to emit a light wave that propagates through the gas to the measuring photodetector. The light source is activated so as to illuminate the gas, so that the light source emits a light pulse. The method also includes measuring, with the measuring photodetector, a measurement intensity of a light wave transmitted by the gas during the illumination, in a measurement spectral band. The measurement spectral band comprises the absorption spectral band. The light source is activated using a pulsed activation signal, each pulse having a specific form, notably to reduce aging of the source.

Gas sensor comprising a pulsed light source

A method&#x2014;for measuring an amount of a gaseous species present in a gas&#x2014;comprises placing the gas between a light source and a measurement photodetector. The light source is able to emit an incident light wave that propagates through the gas to the measurement photodetector. The gas is illuminated with the light source. A measurement intensity, of the light wave transmitted by the gas, is measured with the measurement photodetector. An intensity of a reference light wave, emitted by the light source in a reference spectral band, is measured with a reference photodetector. The illumination and measuring are performed at multiple measurement times, at each of which the gas's absorption of the incident light wave is estimated and an amount of the gaseous species is estimated on the basis of the estimated absorption. Estimating the absorption comprises applying a correction function, that varies over time, to the reference intensity.

Method for analysing a gas by means of double illumination

A device for measuring and tracking over time the quantity or concentration of a component in a fluid comprises: a sensor capable of measuring a quantity or concentration of the component in the fluid and providing a quantitative signal for tracking this quantity or concentration over time; a signal-processing module comprising a low-pass filter of the quantitative tracking signal; and an output interface for providing the filtered quantitative tracking signal. The signal-processing module comprises an estimator of a value of instantaneous trend of variation of the quantitative tracking signal in a predetermined sliding time window. Also provided is means for adjusting over time a high cutoff frequency of the low-pass filter according to the estimated value of instantaneous trend of variation.

Device and method for measuring and tracking the quantity or concentration of a compound in a fluid

A method for analyzing a gaseous sample, by comparing an incident light wave and a transmitted light wave, the method comprising: i) illuminating the sample with a light source emitting the incident light wave propagating up to the sample; ii) detecting a light wave transmitted by the sample; iii) detecting a reference light wave emitted by the light source and representing a light wave reaching a reference photodetector without interacting with the sample; iv) repeating i) to iii) at different measurement instants; v) estimating, at each measurement instant, an intensity of the reference light wave; vi) taking into account the estimated intensity of the reference light wave and the detected intensity of the transmitted light wave to perform a comparison, at each measurement instant; and vii) analyzing the gaseous sample as a function of the comparison.

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Grenoble, France

Thanh Trung Le