GB963197A - Method and apparatus for gas analysis - Google Patents

Abstract

963,197. Gas analysis. E. H. COLEMAN, and G. H. J. ELKINS. Nov. 15, 1961 [Oct. 20, 1960], No. 35931/60. Heading G1B. In an apparatus for continuously analysing a gaseous mixture comprising a number of treatment vessels connected in series with a continuous passage of a stream of gas, different treatment vessels being for removal of different components of the gas mixture whereby the change in volume caused by the removal of the component in the mixture is a measure of the amount of component, the gas stream is initially heated to vaporise any entrained liquid and the first removal stage is for removing vapour from the gas. A katharometer may be connected to the outlet of the last measuring device. A gas mixture from a sampling point is passed through a pipe line, which is heated to prevent condensation therein, to a flow measuring device 11. The device has a vertical conical tube of narrow angle which contains a light bob. The vertical position of the bob in the tube is a measure of the rate of passage of gas. The flow measuring device 11 is enclosed in an insulated cabinet 12 which is maintained thermostatically at a temperature sufficient to vaporize any water contained in the gas, say 105‹C. From the device 11 the gas passes to a treatment column 13. It passes up this column in counterflow to a stream of water for condensing water vapour in the gas, the water running down from a reservoir on top of the apparatus. The gas leaving column 13 passes to flow measuring device 11a. The difference in reading between flow measuring devices 11 and 11a then gives a measure of the water content of the gas mixture expressed as volume of vapour. In calculating the initial water content of the gas mixture, allowance must be made for the water vapour content of the gas leaving the column 13 which is at a known value dependent on the temperature. The gas then passes to the next column, 13a, which removes another component of the mixture, carbon dioxide for example. The content of that component will be measured by the difference in reading between flow measuring devices 11a and 11b. Further components are removed by succeeding columns, each preceded and followed by a flow measuring device. In each of said succeeding columns the gas passes'in counterflow to an aqueous solution of an absorbent or reagent for removing one component of the mixture. Liquid U-trap seals 16, 16a &c. are provided in the liquid outlets from the columns. The movement of gas through the system is maintained by an aspirator or low pressure pump.