Enhanced hydrogen gas detectability of sweep heating thin-wire thermal conductivity detector

Abstract

Enhanced hydrogen gas detectability was demonstrated with the sweep heating thin-wire thermal conductivity detector. The employment of the thinner wire contributes to expanding the detectability. Also, the method for compensating room temperature is proposed based on the resistance measured at the minimum current, which represents room temperature. Therefore, the temperature compensation can be performed without an additional thermometer. Nevertheless, the effect of the compensation is significant, and the fluctuations due to room temperature were removed almost completely. Accordingly, the sensor can detect down to 0.3%H2 (3000 ppm) concentration with 0.1%H2 resolution (0.00007 W/(m∙K) resolution in thermal conductivity), even though the sensing element is only the bulk thin-wire and the operation temperature is near room temperature. This detectability is comparable to the MEMS-based sensor. Therefore, the sweep heating is very powerful, practical, and cost-effective driving method. This is because the sweep heating can acquire much more information as compared with the typical heating methods.