Maintenance and Maintenance of Dissolved Oxygen Meter
A dissolved oxygen meter measures the amount of oxygen dissolved in an aqueous solution. Oxygen is dissolved in water by the surrounding air, air movement and photosynthesis.
Can be used to measure and monitor processes where oxygen levels can affect reaction rates, process efficiency or the environment: e.g. aquaculture, biological reactions, environmental testing (lakes, streams, oceans), water/wastewater treatment, wine production.
Matters needing attention in the daily maintenance and maintenance of the dissolved oxygen meter:
1. Calibrate once a day before using the dissolved oxygen meter, use the water-saturated gas method, and do not need to calibrate again even if the machine is turned off within a day;
2. The temperature difference between calibration and measurement should not be too large, preferably no more than +-5°C;
3. If the reading is abnormal, you must change the membrane of the dissolved oxygen meter (such as the reading is unstable after starting up or does not tend to be stable from high to low);
4. When changing the membrane of the dissolved oxygen meter, there should be no air bubbles in the electrolyte, the membrane should not be wrinkled, and the excess membrane should be cut off;
5. The dissolved oxygen membrane must be replaced when the electrolyte of the sensor of the dissolved oxygen meter is dry;
6. When changing the dissolved oxygen membrane, wash away the old electrolyte with deionized water or distilled water, and drop in 2-3 drops of new electrolyte to dry it. The ordinary dissolved oxygen sensor should be dripped with new electrolyte until the liquid surface bulges, and the dissolved oxygen film should be pressed without leaving any air bubbles; the cover film should be filled with half the amount of new electrolyte and screwed tightly;
7. The cover membrane can be used after replacement, and the ordinary membrane should be left overnight after replacement to allow the membrane to fully restore its balance;
8. The surface of the dissolved oxygen membrane should be cleaned carefully if it is contaminated, and the membrane should not be damaged;
9. When the dissolved oxygen meter is measuring, if there are bubbles continuously at the bottom, the sensor head should be facing up and tied to the cable, so that the bubbles cannot stay on the surface of the dissolved oxygen film;
10. Ordinary dissolved oxygen sensors need to be stirred during measurement, and proper stirring is conducive to obtaining real dissolved oxygen readings. Fast pulse method and microelectrode array (MEA) measurement without stirring;
Calibration method of water-saturated gas method: use "%" method for calibration, unless there are specific requirements, avoid using "mg/l" method; place the sensor in the moisture in the bottle, do not directly contact with water, and do not completely contact the bottle with the atmosphere. Isolation; place it for more than 15 minutes, let the water vapor saturate, tend to balance, or the dissolved oxygen and temperature readings are stable; enter the correct atmospheric pressure value (in mmHg column); the difference between the stable calibration and the measured temperature is not more than +-5°C; confirm the calibration value.
