Measurement and regulation of oxygen content in gases using solid electrolyte cells. III. Oxygen pump-gauge

The technical problems of the conventional one-tube oxygen pump-gauge are reviewed. Several causes of error are shown: the semipermeability of the electrolyte tube, the electric coupling between the pump and the gauge, the existence of local cells due to electric leads deposited on the electrolyte, spurious zero-current voltages. A new set-up involving a microgauge is described. It is capable of producing and measuring within a few per cent accuracy, oxygen-inert gas mixtures with oxygen concentrations ranging down to a few 10−2ppm.