INSTALLATION DE MESURE DE LA CONCENTRATION D'ECHANTILLONS GAZEUX PAR EFFET PHOTOACOUSTIQUE, NOTAMMENT POUR DETECTION DES FUITES DES RECIPIENTS DE GAZ DE PETROLE LIQUEFIES

摘要

A sample of the atmosphere to be analysed is taken and brought to an air-tight chamber (10). This chamber (10) has a reflective surface (15,16) which produces multiple light reflections. A transparent or semi-transparent input window (17) fitted in this wall (15,16) directs a light beam towards the chamber. The light beam is an approximately monochromatic infrared radiation which is modulated at an acoustic frequency and whose wavelength corresponds to an absorption band of the gas to be detected.A sensor (41) moves in response to the pressure variations in the chamber (10). The movements of this sensor (41) are transformed into an electrical signal.