A radioisotope dilution method for the precise absolute determination of the flowrate of gas under industrial conditions

A radioisotope dilution method for the determination of the volume flowrate of gas under industrial conditions is described. Since the technique is independent of the pipeline characteristics and the compressibility of the gas, and depends only on the measurement of volume, time and relative count rates it is absolute and inherently accurate. The r.m.s. error is of the order of a few tenths of a per cent of the mean flowrate. In order to correct the volume flow measurement to mass flow it is only necessary to know the density of the sampled gas at accurately monitored temperature and pressure close to ambient laboratory conditions. The technique has been tested with flows ranging from 62 to 16 000 m3h-1 at pressures from 70 to 3100 kPa. It is recommended that the method be evaluated as international standard for the determination of flowrate of gases under a very wide range of conditions. (author)