Measuring apparatus for determining a quantity correlated with the Wobbe index of a gas or gas mixture and method for maintaining the Wobbe index of gas mixtures constant

摘要

The gas analysis appts. is used to measure the Wobbe number of a heating gas as defined by the calorific value of the gas in M Joules per cubic metre divided by the density of the gas relative to air. The probe line (1) supplied with the gas to be analysed has a throttle (3), with valve and control (2, 4) for monitoring the pressure difference across the latter to ensure that it maintains a constant value. A constant volumetric air stream is delivered to the gas flow before supplying it to a burner jet (10) within a combustion chamber (9) for complete combustion of the gas/air mixt. The exhaust line (11) from the combustion chamber has measuring elements (12, 13) for measuring the oxygen content of the exhaust gases from which the Wobbe number can be obtained.