Self-Test Procedures for Gas Sensors Embedded in Microreactor Systems

Autor: Andreas Helwig, Angelika Hackner, Gerhard Müller, Dario Zappa, Giorgio Sberveglieri
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Sensors, Vol 18, Iss 2, p 453 (2018)
Druh dokumentu: article
ISSN: 1424-8220
18020453
DOI: 10.3390/s18020453
Popis: Metal oxide (MOX) gas sensors sensitively respond to a wide variety of combustible, explosive and poisonous gases. However, due to the lack of a built-in self-test capability, MOX gas sensors have not yet been able to penetrate safety-critical applications. In the present work we report on gas sensing experiments performed on MOX gas sensors embedded in ceramic micro-reaction chambers. With the help of an external micro-pump, such systems can be operated in a periodic manner alternating between flow and no-flow conditions, thus allowing repetitive measurements of the sensor resistances under clean air, R 0 , and under gas exposure, R g a s , to be obtained, even under field conditions. With these pairs of resistance values, eventual drifts in the sensor baseline resistance can be detected and drift-corrected values of the relative resistance response R e s p = ( R 0 − R g a s ) / R 0 can be determined. Residual poisoning-induced changes in the relative resistance response can be detected by reference to humidity measurements taken with room-temperature-operated capacitive humidity sensors which are insensitive to the poisoning processes operative on heated MOX gas sensors.
Databáze: Directory of Open Access Journals
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