Effect of a Series Connection of a Bi-Electrolyte Hydrogen Sensor in a Leak Detector

Abstract

Conventional leak detectors are widely based on helium gas sensors. However, the usage of hydrogen sensors in leak detectors has increased because of the high prices of helium leak detectors and the dearth in the supply of helium gas. In this study, a hydrogen leak detector was developed using solid-state hydrogen sensors. The hydrogen sensors are based on Park–Rapp probes with heterojunctions made by oxygen-ion conducting Yttria-stabilized zirconia and proton-conducting In-doped CaZrO3. The hydrogen sensors were used for determining the potential difference between air and air balanced 5 ppm of H2. Even though the Park–Rapp probe shows an excellent selectivity for hydrogen, the sensitivity of the sensor was low because of the low concentration of hydrogen, and the oxygen on the surface of the sensor. In order to increase the sensitivity of the sensor, the sensors were connected in series by Pt wires to increase the potential difference. The sensors were tested at temperatures ranging from 500–600oC