Calibration method and maintenance of dissolved oxygen meter

Core tips: dissolved oxygen analyzer is a polarographic analysis instrument, specially designed for ppb level dissolved oxygen measurement of boiler feed water and condensate. It ensures the stability and accuracy in (ultra) low concentration, and greatly improves the measurement performance and use environment. Dissolved oxygen meter (2 pieces) dissolved oxygen meter is mainly used for continuous monitoring of dissolved oxygen value in chemical fertilizer, metallurgy, environmental protection, pharmaceutical, biochemical, food and tap water solutions。

　　Dissolved oxygen analyzer is a polarographic analysis instrument, specially designed for ppb level dissolved oxygen measurement of boiler feed water and condensate. It ensures the stability and accuracy in (ultra) low concentration, and greatly improves the measurement performance and use environment. Dissolved oxygen meter (2 pieces) dissolved oxygen meter is mainly used for continuous monitoring of dissolved oxygen value in chemical fertilizer, metallurgy, environmental protection, pharmaceutical, biochemical, food and tap water solutions。

 

　　Dissolved oxygen analyzer has the advantages of easy installation, long calibration cycle (3-4 months), insensitive to other substances, and can monitor the usage of electrolyte in the coated and probe. Generally, the electrolyte and coated can be replaced every one to three years. Dissolved oxygen analyzer can be calibrated by standard solution or on-site sampling. Standard solution calibration method of dissolved oxygen analyzer: standard solution calibration generally adopts two-point calibration, namely zero calibration and range calibration. The zero calibration solution can be 2% Na2SO3 solution. The range calibration solution can be 4 M KCl solution (2 mg / L) and 50% methanol solution (21.9 mg / L) according to the measurement range of the instrument. On site sampling calibration method of dissolved oxygen analyzer (Winkler method): in the actual use of dissolved oxygen analyzer, Winkler method is often used for on-site calibration of dissolved oxygen analyzer. When using this method, there are two situations: when sampling, the meter reading is M1, and the analytical value is a. when calibrating the meter, the meter reading is still M1, and then just adjust the meter reading to be equal to a; When sampling, the meter reading is M1 and the analytical value is a. when calibrating the meter, the meter reading is changed to m2. In this case, the meter reading should be adjusted to 1mA & times; M2 instead of equal to a。

 

　　The electrode of dissolved oxygen meter should be cleaned once every 1 ~ 2 weeks of maintenance. If there are pollutants on the diaphragm, the measurement error will be caused. Be careful not to damage the diaphragm during cleaning. Rinse the electrode of dissolved oxygen meter in clean water. If the dirt can't be washed away, scrub it carefully with soft cloth or cotton cloth. The zero point and range of dissolved oxygen meter electrode should be calibrated again in February to March. The electrode regeneration of dissolved oxygen analyzer is about once a year. When the measurement range cannot be adjusted, it is necessary to regenerate the dissolved oxygen electrode. Electrode regeneration includes changing internal electrolyte, replacing diaphragm and cleaning silver electrode. If the silver electrode is oxidized, it can be polished with fine sandpaper. If the electrode of dissolved oxygen meter is found leaking in use, the electrolyte must be replaced. Referring to the above, the use of dissolved oxygen meter is not only to use it correctly, but also to maintain it. Many customers have problems before they use it. Most of them are technicians who accidentally touch the membrane head and break the membrane when they take the electrode. As a result, there is too much negotiation and turnover repair between customers and suppliers Therefore, when using it, you can be formal and careful, which will avoid a lot of unnecessary trouble。