GAS MONITORING INSTRUMENT UTILIZING FIBER OPTIC, PIEZOELECTRIC AND GAS-SENSITIVE POLYMER TECHNIQUES

The most usual form of instrument for the monitoring of gases such as carbon dioxide involves absorption bands in the infra-red spectrum, wh ich in turn mandates the use of infra-red optics and sensors. The pres ent instrument dispenses with the use of infra-red by employing visibl e light along with a gas-sensitive polymer which changes colour in the presence of CO2, this being a reversible process. The instrument itse lf also utilises a novel realisation of the well-known double-beam-in- time principle in which fibre-optic light guides replace lens systems. The mechanical beam splitting is performed by a piezoelectric bimorph cantilever.