抄録
An electrical-type distributed hydrogen sensor for detection of leak location has been proposed and evaluated. Platinum-supported tungsten trioxide (Pt/WO3) was used as a hydrogen switch material whose electrical characteristics change from insulative to conductive with the exposure to hydrogen gas. This film was firstly coated on the glass substrate using sol-gel technique. Secondly, a couple of Al and Ni-Cr long interdigital electrodes were sputtered onto this film. The operation principle of this sensor is analogous to that of PSD (Position Sensitive Detector). If a part of line-type device is exposed to hydrogen gas, Al and Ni-Cr electrodes are short-circuited because Pt/WO3 hydrogen switch of this point becomes on-state. Therefore, electrical resistance of long electrode is divided at this point and corresponding currents are detected. In our experiments, it was demonstrated that leak location could be determined with the ratio of the currents obtained from both ends as a sensor signal. The response speed was very fast and no influence of leak rate and distance from the device surface to the leakage point on steady-state sensor signal was observed. It is suggested that this method is suitable to detect the leak location of fuel cell equipments with lower-cost and ease.
