How to maintain the hottest dissolved oxygen teste

I. precautions for daily use of dissolved oxygen meter 1 Calibrate once a day before use, using the water saturated gas method, and there is no 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, and should not exceed ＋－ 5 ℃

3. If the reading is abnormal, the dissolved oxygen meter membrane must be replaced (for example, the reading is unstable after startup 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 bubbles in the electrolyte, the membrane should not be wrinkled, and the excess membrane should be cut off completely

5. When the electrolyte of the sensor is dry, the dissolved oxygen film must be replaced

6. When changing the dissolved oxygen film, use deionized water or distilled water to wash out the old electrolyte, drop 2-3 drops of new electrolyte and dry it. Ordinary dissolved oxygen sensors should be filled with new electrolyte until the liquid level bulges, and press the dissolved oxygen film without leaving bubbles; Half a quantity of new electrolyte shall be injected into the covering film and screwed tightly

7. The cover film can be used after replacement, and the ordinary film should be placed overnight after replacement to completely restore the balance of the film

8. If the surface of dissolved oxygen membrane is contaminated, it should be carefully cleaned, and the membrane cannot be damaged

9. YSI officially recommends replacing the dissolved oxygen membrane once every 2-4 weeks, but under the condition of good water quality and proper maintenance, it can even be replaced once every six months, provided that each calibration reading is normal

10. If bubbles constantly appear at the bottom during measurement, the sensor head should be upward and tied to the cable, and the bubbles should not stay on the surface of the dissolved oxygen film

11. Ordinary dissolved oxygen sensors need to be stirred when measuring, and proper stirring is conducive to obtaining true dissolved oxygen readings. Rapid pulse method and microelectrode array (MEA) measurement do not need stirring

II. Calibration

1 Adopt water saturated gas method

2. It is best to use "%" when calibrating, unless professor zhangliqun said that there are specific requirements to avoid using "mg/l" in cement floor paint hg/t 2004 (9) 1 of advanced elastomer material research center of Beijing University of chemical technology

3. Put the sensor in the moisture in the bottle, do not directly contact with water, and do not completely isolate the bottle from the atmosphere

4. Leave it for more than 15 minutes, let the water vapor saturated and tend to balance, or the dissolved oxygen and temperature readings are stable

5. Input the correct atmospheric pressure value (in mmHg column)

6. The difference between the calibration stability and the measured temperature shall not be greater than + - 5 ℃

7. Determine the calibration value

III. maintenance

1 If the do charge exceeds 25-75, polish the sensor

2. If the do gain exceeds 1 + - 0.4, polish the sensor

3. Clean and dry the sensor before polishing, polish the gold cathode with 400 mesh sandpaper, polish the silver anode with 800 mesh sandpaper, polish it in parallel for 10-15 times, wash and dry it, drip 2-3 drops of new electrolyte, dry it, fill it with electrolyte, and replace it with a new film

4. The sensor socket should be dry and clean, and it is strictly forbidden to be wet or contaminated

5. When the sensor is poisoned by hydrogen sulfide or sulfur dioxide, soak it in 3% ammonia for one night, then rinse it, or clean it with ultrasonic, replace it with a new membrane, and recalibrate it

6. If the reading is unstable during calibration or the response is too slow during measurement, the sensor should be maintained (grinding, ammonia immersion or ultrasonic cleaning)

IV. storage

short term 1 Put the sensor in the moisture in the bottle, do not directly contact with water, seal the bottle mouth, and conduct regular detection to ensure that there is automatic standard force water suitable for the electronic tensile testing machine in the bottle

long term: 1 Clean and dry the sensor with deionized water, fill it with new electrolyte, install a new film, and place it in a cool place

2. Or fill the calibration cup with an appropriate amount of water, and place the sensor in the cup for sealing

3. Test once every 1-2 months to ensure that the water is not dry and does not breed microorganisms