Photoacoustic gas detection for fire warning

摘要

A detector for measuring the gas concentration of carbon dioxide based on an infrared photoacoustic principle is presented. Many molecules and particles in the atmosphere cause extinction of an incident beam of infrared radiation due to absorption and scattering processes. The absorption occurs at wavelengths which are very specific for each molecule. In the miniaturized gas detector presented the ambient gas enters a small cell (approx. 1 cm~3) via a diffusion membrane. The gas is irradiated with pulsed infrared light at the specific absorption wavelength for carbon dioxide.