Technical Note 1.Principal Fig. 1 shows a structure of sensing element. The Zirconia disk has oxygen ion conductivity at high temperature. A pair of electrodes is provided for the disk and sensing voltage is applied to them. Oxygen gas is converted to ions at the electrode (Cathode), moving to the other electrode (Anode), then the ions are inverted to oxygen gas once again. The correlation between applied voltage and output current is shown in Fig. 2a. When the sensing voltage is fixed, correlation between oxygen purity and output current is shown in Fig. 2b. Heater: 1.5WDC O2 Current output O2A A Sensing voltage V O2 Fig.1 Cross section of sensing element Current (uA) Current (uA) Oxygen purity 90% 100 100 Sensing voltage=1.5V const. 80% 50 50 60% 40% 21% 0 0 1 2 Sensing voltage (V) Fig. 2a Sensing voltage vs. output current 0 0 20 40 60 80 90 Oxygen purity (%O 2) Fig. 2b Oxygen purity vs output current - Technical note of Fujikura oxygen sensor Fujikura Ltd. Sensor Department 1-5-1, Kiba, Koto-ku, Tokyo 135-8512, Japan phone +81-3-5606-1072 E-mail : [email protected] 1 2.Useful information a) Gas flow rate Applicable flow rate is 100cc/min ~ 5 litter/min. b) Operation temperature Sensor output is stable at –10 ~ +60degC. See appendix for the detail. c) Operation pressure Applicable pressure range is –40kPa ~ +500kPa gauge. Pressure (or flow rate) must be stabilized because the sensor’s output is sensitive to sudden pressure changes, however, the output quickly recovers and becomes stable when the pressure is stable. Slow pressure drift, like atmospheric pressure change, does not affect to sensor output. See appendix for the detail. d) Sampling gas Fujikura oxygen module/monitor is calibrated by O2/N2 mixture gas. If any other gases are contained in sampling gas in the field application, the calibrated accuracy may not be guaranteed. See appendix for the detail. - Appendix - Influence of temperature on the output of a module - Technical note of Fujikura oxygen sensor Fujikura Ltd. Sensor Department 1-5-1, Kiba, Koto-ku, Tokyo 135-8512, Japan phone +81-3-5606-1072 E-mail : [email protected] 2 Influence of humidity on the output of a module Sensor output is stable down to 0.6atm. Pressure drift (Static) in free air - Technical note of Fujikura oxygen sensor Fujikura Ltd. Sensor Department 1-5-1, Kiba, Koto-ku, Tokyo 135-8512, Japan phone +81-3-5606-1072 E-mail : [email protected] 3 Sensor output is drifted by rapid pressure change, but it recovers in short period. Sensor output is stable to slow pressure change. Pressure drift (Dynamic) in free air Influence of Ar on the output of a module - Technical note of Fujikura oxygen sensor Fujikura Ltd. Sensor Department 1-5-1, Kiba, Koto-ku, Tokyo 135-8512, Japan phone +81-3-5606-1072 E-mail : [email protected] 4 Influence of CO2 on the output of a module 1st October , 2011 - Technical note of Fujikura oxygen sensor Fujikura Ltd. Sensor Department 1-5-1, Kiba, Koto-ku, Tokyo 135-8512, Japan phone +81-3-5606-1072 E-mail : [email protected] 5