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Thermal-magnetic oxygen analyzer and the principle of Zirconium Dioxide Oxygen Sensor

2010-11-12 17:19:14

The oxygen analyzer used mainly zirconia thermal magnetic type and two.

Dew point meter, oxygen analyzer, infrared analyzer, hydrogen analyzer, coke oven gas oxygen analyzer, Alarm, calcium carbide furnace exhaust gas analyzer, gas analyzer cement kilns, semi-water gas analyzer pulverized coal injection system.

(1) Zirconium Dioxide Oxygen Sensor analyzer

Zirconia (ZrO2) is a ceramic, a solid character with ionic conductivity. At room temperature for single crystal, when the temperature was increased to 1150 ℃, the crystal structure into a cubic crystal, while about 7% of the volume shrinkage; when the temperature decreases, and becomes monoclinic crystal. If the repeated heating and cooling, ZrO2 will rupture. Therefore, the pure ZrO2 not be used as measuring element. If a certain amount of ZrO2 added calcium oxide (CaO) or yttria (Y2O3) as stabilizer, and then roasted at high temperatures, then becomes stabilized zirconia materials, time, zirconium by tetravalent or divalent calcium trivalent yttrium replacement, while producing oxygen ion hole, so the solid electrolyte ZrO2 are anions. ZrO2 movement mainly through the hole conductivity, when the temperature reaches above 600 ℃, ZrO2 becomes a good oxygen ion conductor.

(2) thermal-magnetic oxygen analyzer

The principle is the use of oxygen in flue gas composition are particularly high susceptibility to determine the physical properties of the oxygen content in flue gas. Paramagnetic oxygen gas (gas that can be attracted by the magnetic field is called paramagnetic gas), non-uniform magnetic field in the flow field are attracted to strong place. With heating wire in the area, so that here the magnetic susceptibility of oxygen and temperature decrease, and thus reduce the magnetic attraction, not by heating the back of the higher susceptibility of oxygen molecules push the discharge magnetic field, resulting "magnetic wind" or "thermal magnetic flow" phenomenon. Gas sample at a certain temperature, pressure and flow rate, by measuring the size of the magnetic wind can be measured oxygen content in air samples. Because the thermal elements (platinum wire) both as unbalanced bridge arm resistance of the two bridges, shopping search and as a heating resistance wire, under the effect of the magnetic wind of the temperature gradient, that is, the intake side of the leg below the outlet temperature side of the bridge arm of the temperature. With the unbalanced bridge to the oxygen content in gas samples from the different, the output voltage accordingly.

Zirconia electrolyte in the sintering of a platinum electrode on each side, when the zirconia oxygen partial pressure on both sides is not the same side of the high oxygen partial pressure of oxygen in the form of ions migrate to the side of the low partial pressure of oxygen, resulting in partial pressure of oxygen the high side of the platinum electrode lose electrons were positive, while the low side of the partial pressure of oxygen by platinum electrode negatively charged electron, and thus the two platinum electrodes in the oxygen concentration difference between electric potential. The potential at a certain temperature only on both sides of the gas when the oxygen content difference (oxygen concentration) related. If the oxygen content in the side is known, the other side of the oxygen content in comparison and can be potential with oxygen concentration that the measured oxygen concentration potential, he will know the flue gas oxygen content.