Gas analyser resolving mixt. by heated catalyser wire - automatically limits concn. of resulting highly aggressive components

摘要

After passing through a diffusion zone, a gas mixt. for analysis is catalytically broken down with components by a heated catalytic wire, with the individual components then delivered to an electro-chemical sensor producing signals related to the concn. of each component, to be processed in a comparison circuit. To counter the highly corrosive effect of particular components, the detector signal is compared with a threshold value representing the max. desired concn. of that component, and above that threshold forms a control signal keeping the concn. of the component generally constant, e.g. by controlling the temp. of the catalytic wire, or at least the surface thereof. Such modulation may be continuous or intermittent. The diffusion zone may be a `TEFLON' membrane, and the heating wire formed of Pd and/or Pt and the detector formed as an array of individual detectors. ADVANTAGE - Analyser can dial with chlorinated hydrocarbons which form corrosive Cl2 which could shorten operative life.