Non=dispersive two beam gas analyser

摘要

The analyser has a measurement vessel (2) which can be filled with a measurement gas and irradiated by a measurement beam (6). The analyser also has a comparator vessel (3) which can be filled with a comparison gas and irradiated by a comparison beam (7). The comparison vessel (3) is connected to two spaced apart terminals (10,11) in a closed comparison gas circuit. The circuit contains an absorption substance (21). A device (13) which conveys the comparison gas by heat convection is arranged in the circuit. The gas conveying device (13) may have an essentially perpendicular tube arranged at its ends in the comparison circuit via gas terminals. A heating element may be arranged in the lower end of the tube.