Optoacoustic gas sensor
AssigneeCerberus AG
InventorMartin Forster
Life of this patent
Estimating the term…
Abstract
In an optoacoustic gas sensor having a sensor body (1, 2), a light source (10), a measurement cell (6) with a gas-permeable membrane (15), a measurement microphone (13), and an optical measurement filter (11) between the light source (10) and the measurement cell (6), a reference cell (7) is included that is separate from the measurement cell (6). The reference cell (7) has a reference microphone (14) that is shielded against optoacoustic signals from the gas to be detected via the reference cell being substantially free from intensity-modulated optical radiation having an absorption wavelength of the gas to be detected. The measurement signal, which indicates gas concentration, is obtained by subtraction of the signals from the two microphones (13, 14).
Claims10
An optoacoustic gas sensor having a sensor body comprising:
- a light source (10) for emitting intensity-modulated optical radiation including an absorption wavelength of a gas to be detected;
- a measurement cell (6) in optical communication with the light source (10) and in atmospheric communication with an ambient atmosphere, and comprising a measurement microphone (13) disposed for generating a measurement signal which at least in part is due to optoacoustic pressure variations from the gas to be detected;
- a reference cell (7) in atmospheric communication with the ambient atmosphere said reference cell being substantially free from intensity modulated optical radiation having an absorption wavelength of the gas to be detected and comprising a reference microphone (14) disposed of generating a reference signal which is substantially free of a signal component due to optoacoustic pressure variations from the gas to be detected;
- and
- evaluation electronics connected to the measurement microphone (13) and the reference microphone (14) for generating an output signal which represents the measurement signal minus the reference signal.
Dependencies are inferred from the claim text.