COSA Xentaur COSA 9610 - Manual (Page 6)

INSTALLATION, OPERATION AND MAINTENANCE MANUAL – COSA 9610™
Page 6 of 44
1.2.1. Oven with oxygen sensor
The gas/air mixture is burnt catalytically in an oven, which is kept at 812ºC with a burning
spiral. The temperature is maintained with a temperature controller using a K-type
thermocouple. The oxygen sensor in the oven is a zirconium oxide cell. This is mounted
such, that one side is in contact with the outside air and the other side with the flue
gasses. At high temperatures, (600ºC) O
2
-ions in the ZrO
2
grating become mobile through
vacancies herein. By fixing porous Pt-electrodes at both sides of the ZrO
2
, O
2,
gas
molecules can through diffusion by and uptake of two electrons from the Pt electrode enter
the ZrO
2
as O
2
-ion, move to the other electrodes and be converted in gaseous O
2
again by
release of the two electrons.
Inlet
Air/Gas
Mixture
Oven
Heating Spiral
Oxygen Sensor
Drain
Vent