Electrode Calibration of Dissolved Oxygen Meter
(1) The electrode should be cleaned once every 1 to 2 weeks. If there are pollutants on the diaphragm, it will cause measurement errors. Care should be taken when cleaning, taking care not to damage the diaphragm. Rinse the electrode in clean water. If the dirt cannot be washed off, carefully scrub it with a soft cloth or cotton cloth.
(2) The zero point and span should be re-calibrated every 2 to 3 months.
(3) Electrode regeneration is performed about once a year. When the measurement range cannot be adjusted, the dissolved oxygen electrode needs to be regenerated. Electrode regeneration includes replacing the internal electrolyte, replacing the diaphragm, and cleaning the silver electrode. If the silver electrode is observed to be oxidized, it can be polished with fine sandpaper.
(4) If in use
If the electrode leaks, the electrolyte must be replaced.
Referring to the above, the use of the instrument is not only to use it correctly, but also to maintain it. Customers and friends must understand these things in their hearts and learn to protect these instruments and meters, not just the dissolved oxygen meter. Prolonging its service life is to save a lot of money for more businesses.
1. Calibration method of dissolved oxygen meter: Generally, standard liquid calibration or on-site sampling calibration can be used.
(1) Standard solution calibration method: 2% Na2SO3 solution. Range calibration solution can choose 4M KCl solution (2mg/L) or 50% methanol solution (21.9mg/L) according to the measurement range of the meter. Standard solution calibration generally adopts two-point calibration, that is, zero point calibration and span calibration. Zero calibration solution can be used
(2) On-site sampling calibration method (Winkler method): In actual use, the Winkler method is often used for on-site calibration of dissolved oxygen analyzers. When using this method, there are two situations: when sampling, the meter reading is M1, and the analytical value is A. When the meter is calibrated, the meter reading is still M1. At this time, it is only necessary to adjust the meter reading to be equal to A; when sampling, the meter reading is M1, the laboratory analysis value is A, and the meter reading is changed to M2 when the meter is calibrated. At this time, the meter reading cannot be adjusted to be equal to A, but the meter reading should be adjusted to 1MA×M2.
