GB824854A - A method of and an apparatus for gas analysis - Google Patents

Abstract

<PICT:0824854/III/1> The constituents of a gas mixture, e.g. flue gas and inflammable gas mixtures, are measured by combustion with the oxygen contained in the mixture, or added thereto, measuring the change in oxygen content in a paramagnetic oxygen meter where the flowing gases are exposed in a thermal conductivity cell to a constant inhomogeneous magnetic field both before and after combustion, and in then determining the difference in oxygen content. From this result the calorific value of the combustible constituents, or the proportion of other reactable components can be determined. The consumption of oxygen in combustion with a range of combustible gases is given in the Specification. The gas mixture enters a pipe 1, Fig. 1, and a part flows through combustion chamber 4, and the other part through a compensating chamber 5, together with a known amount of oxygen or air from a pipe 20 if required. The outlets from chambers 4 and 5 lead through two-way valves 6, 7 to a paramagnetic oxygen meter 10. The gas not under measurement passes through a by-pass 14, 15. The oxygen concentration is indicated on a meter 13, and co-ordinated measurements shown on a recorder 12. In modifications, two or four paramagnetic oxygen meters are used, and connected in a Wheatstone bridge circuit, the unreacted gas to be tested passing through one meter or a pair of meters, and the reacted gas passing through the second, whereby a direct reading of the combustible constituent is obtained. In addition the circuit may be unbalanced so that the zero reading accounts for the air of oxygen added.