Hydrogen is considered to be a hazardous gas since it forms a flammable mixture between 4 to 75%2by volume in air. Hence, the safety aspects of handling hydrogen are quite important. For this, ideally, highly selective, fast response, small size, hydrogen sensors are needed. Although sensors based on different technologies may be used, thin-film sensors based on palladium (Pd) are preferred due to their compactness and fast response. They detect hydrogen by monitoring the changes to the electrical, mechanical or optical properties of the films. We report the development of Pd-doped tin-oxide based gas sensors prepared on thin ceramic substrates with screen printed platinum (Pt) contacts and integrated nicrome wire heaters. The sensors are tested for their performances using hydrogen nitrogen gas mixtures to a maximum of 4 %2H(2) in N(2). The sensors detect hydrogen and their response times are less than a few seconds. Also, the sensor performance is not altered by the presence of helium in the test gas mixtures. By the above desired performance characteristics, field trials of these sensors have been undertaken. The paper presents the details of the sensor fabrication, electronic circuits, experimental setup for evaluation and the test results.
Times Cited: 0 Joint Cryogenic Engineering Conference/International Cryogenic Materials Conference Jun 28-jul 02, 2009 Tucson, AZ Adv Res Syst; Amuneal Mfg Corp; Cryofab; Cryomech; Cryocomp, DLH Ind; Essex Cryogen Mo Inc; GE Global Res Ctr; Janis Res Co; Linde Kryotech AG, Linde Nitrogen; Metropolitan Tucson Convent & Visitors; Meyer Tool & Mfg; Nexans; PHPK Technologies; Precis Cryogen Syst; RUAG; Sci Instruments; SuperPower Inc; SupraMagnetics; Velan 0