Patent ID: 7981364
Filing Date: 2011-07-19
Classification: G01N,Y10T

Abstract:
1. A colorimetric gas detector system for detecting and/or measuring the presence of a target gas in an atmosphere being monitored, the system comprising: a) a gas sensing station configured to bring a sample of gas from the atmosphere into contact with a substrate that carries a colour-change material; b) a holder configured to support the substrate and advance successive substrates or successive parts of the same substrate to the gas sensing station; c) an applicator for applying a predetermined dose of a chemical held within the applicator onto a region of the substrate containing colour change material, d) a plenum chamber on a first side of the substrate, when the substrate is in the gas sensing station, the plenum chamber drawing gas from the atmosphere on a second side of the substrate to the first side of the substrate so that the gas travels through or past the region of the substrate containing the colour change material before entering the plenum chamber; e) a radiation detector downstream of the applicator and arranged to detect (i) the radiation absorbed or transmitted by the colour-change material carried by the substrate to which the chemical is applied and (ii) the radiation absorbed or transmitted by the colour-change material carried by the substrate that is contacted by gas from the atmosphere and then to generate signals in accordance with the radiation detected, the holder advances the region of the substrate containing the colour-change material from the applicator to the radiation detector; and f) a processor configured to process the signals from the radiation detector and calculate the amount of target gas in the atmosphere from the signal derived from the radiation detected at e)(ii).