Cleaning an Online Dissolved Oxygen Probe

Regular cleaning keeps an online dissolved oxygen analyzer accurate and extends probe life. Before starting, isolate the probe from the process, shut off power, and follow site safety rules. Wear gloves and eye protection, especially when handling acid cleaning solutions.

First, remove the probe from its holder or flow cell. Rinse it gently with clean water to remove loose deposits. If the probe uses a membrane, inspect it for damage, wrinkles, or coating. Wipe the membrane with a soft cloth or sponge moistened with warm water and a few drops of mild detergent. Do not rub hard, because scratches or pinholes will change the reading.

For inorganic scale, such as calcium carbonate, soak the sensing end briefly in a dilute acid solution recommended by the manufacturer, then rinse thoroughly with deionized water. For biological slime or oil, use a mild alkaline cleaner or diluted detergent. Avoid organic solvents, strong abrasives, and high-pressure water, which can damage the membrane or optical window.

If the probe is optical, clean the fluorescent sensing cap or lens with a soft lens tissue and a small amount of mild detergent. Rinse and dry gently. For electrochemical probes, check the electrolyte level and membrane condition after cleaning. Replace the membrane cap or electrolyte if it is contaminated, torn, or depleted.

After cleaning, reinstall the probe, restore the sample flow, and allow the reading to stabilize. Then perform calibration according to the manufacturer’s procedure, using a known standard or air-saturated water. Record the cleaning date, method, and calibration result. With routine cleaning and careful handling, the probe will provide reliable dissolved oxygen data over a long service period.