Thermal Conductivity Detector for Gas Mixtures Having at Least Three Components

摘要

A gas analyzer for a gas mixture with at least three components includes a channel guiding the gas mixture, a thermoelement probe with a measuring point in the interior of the channel and a cold junction in thermal contact with the channel wall, a control device for pulsed activation of the thermoelement probe, a measuring device for measuring voltage at the cold junction in pauses between current pulses, and an evaluation device for determining temperature differences and calculating the ratio of the components of the gas mixture from temperature difference values determined at different time instant pauses, wherein the control device generates current pulses with at least two different energy contents and the temperature difference values at the first time instant in the pause after a current pulse with a higher energy content and used for the calculation is higher than with a current pulse with a lower energy content.