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US 2015/0085288 A1Published application
Method and Gas Analyzer for Measuring the Concentration of a Gas Component in a Sample Gas
AssigneeSiemens Aktiengesellschaft
InventorFranz STEINBACHER
Life of this patent
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Abstract
Gas analyzer and method for measuring the concentration of a gas component in a sample gas, wherein the wavelength of the light of a wavelength-tunable light source is varied within periodically successive sampling intervals and, in the process, additionally modulated with a frequency to perform wavelength dependent sampling of an absorption line of a gas component to be measured in the sample gas.
Claims8
A method for measuring concentration of a gas component in a sample gas via a gas analyzer, the method comprising:
- varying a wavelength of tight of a wavelength-tunable light source in periodically successive sampling intervals and, during which, sinusoidal modulation with a modulation frequency is also implemented to perform wavelength-dependent sampling of an absorption line of interest of the gas component;
- guiding modulated light through the sample gas to a detector, demodulating a measurement signal generated by the detector at a second harmonic of the modulation frequency;
- evaluating an obtained demodulated measurement signal to form a measurement result for each sampling interval;
- additionally modulating the wavelength of the light of the light source with at least one further frequency which is greater than a next lowest further frequency or the modulation frequency by twice a magnitude of the modulation frequency;
- additionally demodulating the measurement signal at the second harmonic of the at least one further frequency;
- and
- combining at least one further obtained demodulated measurement signal with the demodulated measurement signal or evaluating the at least one further obtained demodulated measurement signal to form a further measurement result which is combined with the measurement result.
4 more elements
A gas analyzer for measuring the concentration of a gas component in a sample gas, comprising:
- a wavelength-tunable light source;
- a modulation apparatus which varies the wavelength of the light of the light source within periodically successive sampling intervals and simultaneously additionally modulates wavelength of the light of the light source with a modulation frequency to obtain wavelength-dependent sampling of an absorption line of interest of the gas component;
- means for guiding the modulated light through the sample gas to a detector;
- and
- an evaluator which demodulates a measurement signal generated by the detector at a second harmonic of the frequency and evaluates the measurement signal to form a measurement result for each sampling interval,
- wherein the modulation apparatus is configured to additionally modulate the wavelength of the light of the light source with at least one further frequency which is greater than a next lowest further frequency or modulation frequency by an amount which is twice a magnitude of the modulation frequency;
- and
- wherein the evaluation apparatus is configured to additionally demodulate the measurement signal at a second harmonic of the at least one further frequency and one of (i) combine at least one further obtained demodulated measurement signal with the demodulated measurement signal and (ii) evaluate the at least one further obtained demodulated measurement signal to form a further measurement result which is combined with the measurement result.
5 more elements
Dependencies are inferred from the claim text.