Title :
Ambient hydrogen chloride sensing with a zinc-coated piezoelectric crystal resonator
Author_Institution :
Bell Commun. Res., Red Bank, NJ, USA
Abstract :
The author discusses a simple yet reliable scheme for the selective and sensitive detection of gaseous HCl utilizing a zinc-coated quartz-crystal resonator as the sensing element in a piezoelectric microbalance operating in a frequency-time differential mode. Detection is based on the rapid formation of the hygroscopic ZnCl/sub 2/ salt with the concomitant uptake of water for ambient relative humidities greater than 10%. The sensitivity ratio for detection of HCl as compared to other common ambient gases is 100:1 or greater. The author also discusses the results of small-scale fire tests, conducted in a telecommunications central office (CO), that demonstrate the benefits derived from ambient HCl sensing with an emphasis on the comparison of the response to commercial fire/smoke detection methods. Studies conducted in several COs have shown that sensor lifetime is expected to exceed about three years.<>
Keywords :
chemical variables measurement; crystal resonators; electric sensing devices; fires; gas sensors; hydrogen compounds; piezoelectric transducers; PVC; fire/smoke detection; frequency-time differential mode; gaseous HCl; hygroscopic ZnCl/sub 2/ salt; piezoelectric microbalance; sensor lifetime; small-scale fire tests; telecommunications central office; Central office; Chemicals; Electronic equipment; Fires; Gas detectors; Hydrogen; Polymers; Smoke detectors; Thermal decomposition; Zinc;
Conference_Titel :
Solid-State Sensors and Actuators, 1991. Digest of Technical Papers, TRANSDUCERS '91., 1991 International Conference on
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-87942-585-7
DOI :
10.1109/SENSOR.1991.148946