The structure of the zirconium oxide sensor The zirconium oxide film is sandwiched between two Pt electrodes. The working principle of the zirconium oxide sensor is that the oxygen ions in the zirconium oxide can move freely at high temperatures (>700oC), and can conduct oxygen ions but not conduct electricity. When the oxygen concentration on both sides of the zirconia film is different, a voltage will be generated between the two electrodes, and the voltage is proportional to the logarithm of the oxygen concentration. Therefore, the zirconia sensor detects the difference in oxygen concentration on both sides of the zirconia film. When detecting the oxygen concentration in an unknown gas, the other side of the zirconia film needs to be a gas with a known oxygen concentration, that is, the reference gas. The reference gas of the ordinary zirconia sensor is air.
2. Analysis of the advantages and disadvantages of the two oxygen probes.
1, electrochemical fuel cell
Advantages: 1) The zero point is accurate, not easy to drift, and only a single point calibration is required; from the chemical reaction formula, it can be seen that when there is no oxygen, there is no current, so the zero point of the electrochemical fuel cell is accurate, and only a single point is required for calibration. Correction.
2) Strong resistance to the influence of organic solvents. Electrochemical fuel cell detection of oxygen is a redox chemical process at room temperature, so it is less affected by a small amount of common organic solvents.
3) The replacement cost is low, only the fuel cell needs to be replaced. When the fuel cell fails and the oxygen analyzer fails, the user only needs to replace the chemical fuel cell in the oxygen probe, and the replacement cost is less than one-third of the price of the entire probe.
Disadvantages: 1) Prolonged contact of the oxygen probe with high-concentration oxygen will affect its life. The battery needs to be stored in a high-purity inert gas, which is not a problem in glove box applications.
2) Cannot be used to detect high temperature gas
2, zirconia sensor
Advantages: 1) Fast reaction time, can measure oxygen concentration under high temperature, high pressure and low pressure, such as boiler exhaust, etc.;
2) It can be in contact with air when it is not detected, and can be stored in the air for a long time, because the reference gas of the zirconia sensor is air.
Disadvantages: 1) Not suitable for use in gases containing organic solvents; zirconia sensors need to work at high temperatures. When the detection gas contains an organic solvent, the organic solvent will chemically react on the electrode, and the oxygen will react with the organic matter and be consumed, making the measured oxygen value lower than the actual value.
2) The zero point is easy to deviate. When measuring PPM gas, it is necessary to frequently use standard gas calibration; because air is used as the reference gas, when detecting 1PPM gas, the concentration difference is more than 200,000 times. It is more difficult to accurately detect and needs to be calibrated frequently. Before each test, use a standard gas for calibration.
3) Only the entire oxygen probe can be replaced, and the replacement cost is high.
3. Which oxygen probe is more suitable for glove box?
Based on the above analysis, the electrochemical fuel cell technology is more suitable for testing the trace oxygen in the glove box. Huali Company uses electrochemical fuel cells.
Features of Dew Point Meter
1. A variety of output parameters: display a variety of humidity parameters, such as dew point/frost point temperature, relative humidity, ppmv (volume of moisture/dry gas) and ambient temperature;
2. The measurement data is displayed on the LCD display in digital or graphical manner, and the output readings can be converted into real-time graphics with a single button.
3. Easy-to-use user interface, fixed keys refer to graphics, hold/save and record keys;
4. It can record on-site data, Z can reach up to 2700 points, and can be equipped with MI70 to connect to Windows software programs;
5. Lightweight and sturdy structure, protected by a waterproof and dust-proof shell, can be used stably in extremely harsh environments, suitable for various occasions;
6. The battery can make the meter be used outdoors for a long time.
Dew point meter application field
1. Dew point measurement of SF6 gas in power system and hydrogen in power plant;
2. Quality control of compressed dry air and power air;
3. Drying industry;
4. Food industry;
The dew point meter is mainly used in petrochemicals, natural gas, dry gas and compressed gas, generator cooling hydrogen, transformer and high-voltage switch insulation gas, welding gas, and oxygen for ships and aviation.
Oxygen sensor working principle PDF
Semiconductor temperature sensor
Zirconia oxygen sensor working principle
Zirconia oxygen sensor calibration