Simple thermal conductivity cell using a miniature thin film printed circuit for analysis of binary gas mixtures

摘要

We describe a thermal conductivity cell for the measurements of the composition of binary gas mixtures. The main advantage of the cell is that its response is pressure independent in the range 20ndash;100 Torr. The apparatus, of the parallel plate type, uses a very thin printed circuit film as the hot plate in order to achieve a fast response time. The cell was designed and operated to determine the orthohyphen;parahyphen;composition of hydrogen gas samples but it also works reliably as an analyser of3Hendash;4He gas mixtures. In both cases the precision of the instrument is better than 10minus;2for the mole fraction.