| Answer |
When there is a large amount of moisture in the sample gas, it might condense into water on a sensor and cause damage to the sensor. Hence, measurement should be performed after removing condensed water from the surface of the sensor. Besides, as described in Q6, when moisture is present at above 700°C which is the commonly required temperature range for zirconia oxygen sensors to function properly, it will be decomposed to oxygen and hydrogen to increase oxygen partial pressure. With no hydrogen in the gas, it is not very necessary to remove water vapor for measurement, but if hydrogen exists together in the gas, removal of water vapor will lead to smaller oxygen partial pressure measured than real. Therefore, for accurate measurement, it is recommended to keep moisture from condensing into water rather than to remove it from the gas. |
