How zirconia probes work

Zirconium oxide sensor is a zirconium oxide ceramic sensor used to measure the oxygen content in the flue gas of a large supercritical boiler.It is a large number of boiler oxygen content measurement equipment, simple structure and rapid response, accurate measurement and other advantages.

Zirconia probe is the use of stable cubic zirconia ceramic in the above 650 ℃ environment produce oxygen ionic conduction properties and design, in a certain temperature conditions, if the zirconium dioxide gases on either side of the block ceramics exist in different oxygen concentration in the zirconium dioxide oxygen ion migration in ceramic, by zirconium dioxide leads on both sides of the electrode, measurable to stable millivolt level signal, we call it the oxygen potential.The sensor device consists of metal housing, measuring battery, heater, thermocouple, filter element and cable terminal.The measurement battery body is divided into three layers: platinum (electrode) - zirconium oxide (electrolyte) - platinum (electrode).Platinum electrodes are porous.Flue gas passes through the filter or the calibration gas passes through the conduction tube to the measured gas side of the measuring battery, while the other side is the reference air (20.60% oxygen).
 

Two gases with different oxygen concentrations act on the cell to produce a logarithmic potential (the greater the difference in oxygen concentrations on either side, the greater the potential signal).The millivolt signal is converted to a standard current of 0 -- 10mA or 4 -- 20mA by an oxygen analyzer.This current is output by the oxygen analyzer terminal.In engineering practice, one side of zirconia is injected with a gas with known oxygen concentration, which we call reference gas, such as air, standard gas, etc., and the other side is the measured gas, which is the flue gas of the furnace that we want to detect.The zirconia probe's output signal is the oxygen potential signal.