Packaging and testing of a hydrogen safety sensor prototype

In this article, testing of an electrochemical, potentiometric hydrogen safety sensor is reported within a proposed packaging scheme. Device packaging under static and flow testing conditions are presented. During the static volume sensor testing, the sensors response is compared against a calibrated Gas Chromatography (GC) measurement. Also, a commercial H2 sensor is incorporated into the test chamber to act as a benchmark for the sensor prototype. In the testing phase, H2 selectivity is demonstrated using pulsed discharge technique.The packaging schemes for static and flow condition testing permit easy handling and exchange of the laboratory prototype sensors with other agencies for independent testing/performance validation. Upon testing, for a fixed inlet concentration of 2% (20,000 ppm) H2 and within the duration of the typical experiment conducted within a non-sealed test chamber, the sensor sees only around 6200 ppm as confirmed by the GC measurements. The sensitivity is around 105 mV for 6200 ppm of H2. While a logarithmic correlation of the sensor output with H2 concentration is observed in laboratory based H2 sensor, the commercial device suffered from an elevated baseline (due to reduced barometric pressure conditions of 2195 m elevation), humidity and uncorrelated sensor output for different H2 concentrations. The pulsed discharge scheme for achieving hydrogen selectivity holds a great potential for tackling cross-sensitivity problems that affect many H2 sensor technologies.

► A unique test apparatus was built to simulate the hydrogen leak in static environment.
► The hydrogen sensors were packaged to permit easy handling and field testing.
► The hydrogen sensor response was compared against a calibrated Gas Chromatography measurement.
► Hydrogen selectivity was demonstrated using a novel signal conditioning technique.