GB448234A - Apparatus for measuring the acidity of gases - Google Patents

Abstract

<PICT:0448234/III/1> The acidity of sulphuric acid plant exit gases and the like is determined by contacting the gas with a standard oxidizing and absorbing solution such as hydrogen peroxide and then testing the latter, e.g. by the electric conductivity method. The solution and the gas are contacted first in an oxidizing chamber and then in an absorption chamber so arranged that the same portions of gas and liquid are in contact with each other in each case. The gas pressure and the head of solution are also maintained constant. As shown, solution from the reservoir 1 flows under constant head 2--3 into the oxidizing chamber 6, then through constant-head device 11 into absorption chamber 12, and finally through constanthead device 20 into the conductivity cell 26. The gas enters at 8 and is drawn in turn through the oxidation and absorption chambers by the siphon 24 at a rate indicated by flow gauge 21, a drying-vessel 19 being provided to prevent condensation in the flow gauge. The conductivity cell is connected to a recording ohmmeter (not shown). At regular intervals a standard resistance may be momentarily inserted in the circuit in place of the cell to provide a calibration point on the chart.