1Online dissolved oxygen analyzerCleaning specifications for sensors
Sensors are the core components of dissolved oxygen meters, and surface contamination can directly affect measurement accuracy. Differentiated cleaning plans need to be developed based on usage scenarios:
Cleaning frequency
Laboratory/clean water quality: Clean once every 2 weeks to avoid dust or chemical residue from adhering.
Surface water/mild pollution: Clean once a week to prevent algae or sediment accumulation.
Industrial wastewater/aquaculture ponds: Clean once every 3-5 days and strengthen maintenance for high pollution environments.
Cleaning tools and steps
Power off operation: Before cleaning, disconnect the power supply to ensure safety.
Physical wiping: Use a soft bristled brush (made of nylon material) to gently remove sediment, algae, and other attachments on the surface of the probe, avoiding scratching the fluorescent coating.
Chemical cleaning:
Dip a lint free cloth or cotton ball into ≥ 95% anhydrous ethanol, wipe the optical window (fluorescence sensing area), and dissolve any oil or organic residue.
If stubborn biofilms (such as algae or microorganisms) are attached, the probe can be soaked in a 5% dilute hydrochloric acid solution for 1-3 minutes, and then thoroughly rinsed with distilled water (only applicable to corrosion-resistant probes, please confirm the instructions in advance).
Oil pollution should be wiped with carbon tetrachloride or specialized cleaning agents to avoid cleaning agents containing abrasives.
Rinse and air dry: Rinse the surface of the probe with distilled water to remove residual stains and ethanol, and place it in a cool place to air dry naturally (avoid direct sunlight).
Special scenario handling
Salt crystallization: Check the surface of the probe for salt crystals every week and rinse with distilled water to remove them (do not use tap water, as minerals may remain).
Automatic cleaning device: can be equipped with ultrasonic cleaner or rotating brush, set to clean once a day, reducing manual maintenance frequency.
2、 Electrode replacement specifications
The electrode is a vulnerable component of the dissolved oxygen meter and needs to be replaced regularly to ensure measurement accuracy. The replacement cycle is usually 1-2 years, depending on the usage environment and frequency.
Preparation before replacement
Power off operation: Turn off the power of the analyzer to ensure that the equipment is in a power-off state.
Spare parts preparation: Prepare new electrodes to ensure that the model matches the instrument.
replacement steps
Dismantling old electrodes:
Find the old electrode position according to the operation manual (usually attached to a fixed socket or connector).
Gently rotate or unscrew the electrode and remove the old electrode.
Cleaning electrode socket: Gently wipe the electrode socket with a suitable solution or cleaning agent to ensure that there is no dirt or residue.
Install new electrode:
Remove the new electrode from the packaging, pay attention to the indicated arrow or mark, and ensure that it is correctly inserted into the socket (which usually has corresponding markings).
Gently rotate or press the electrode to ensure a secure connection.
Calibration and Testing:
Perform electrode calibration (such as air calibration, zero calibration, etc.) according to the operation manual.
After calibration, perform dissolved oxygen analysis to verify the accuracy of the new electrode (error should be ≤ ± 2% or within the manufacturer's specified range).
Precautions for electrode maintenance
Avoid touching the gold cathode: When replacing the membrane, do not touch the surface of the gold cathode with your hands, as grease can affect the electrode characteristics.
Electrolyte treatment:
When replacing the membrane, it is necessary to empty the old electrolyte and inject new electrolyte until it overflows, ensuring that there are no bubbles.
The electrolyte contains less than 1% potassium hydroxide. Avoid contact with eyes. If accidentally touched, rinse with plenty of water.
Short term storage: If the electrode needs to be stored for a short period of time, it should be kept moist (such as in a protective cover with a damp sponge) to avoid measurement drift caused by dryness.
IIIOnline dissolved oxygen analyzerData Recording Standards
A complete data record is an important basis for analyzing instrument performance and tracing the root cause of problems. A systematic record system needs to be established, covering the following contents:
Adjustment record
Date and personnel of calibration: Record the calibration time, names of participants, and work units.
Adjust the environment: Record environmental parameters such as temperature, pH value, turbidity, etc.
Instrument parameters: Record the instrument model, parameter settings, operating procedures, etc.
Data results: Record standard solution calibration data, sample measurement data, etc.
Data recording and analysis
Rationality analysis: Based on water environment information and measured data, evaluate whether the calibration effect meets the accuracy and precision requirements.
Trend analysis: Analyze whether there is a gradual change in the difference between upstream and downstream data of the same instrument during multiple calibrations, and adjust the instrument in a timely manner.
Comparative analysis: Compare multiple calibration records to find differences in instrument calibration and consistency in results.
Randomness analysis: Record each calibration data, analyze randomness, and find regularity to optimize calibration strategies.
data application
Technical support documents: available for other testing personnel to call upon, improving testing efficiency and accuracy.
Regular update and maintenance: Use records as the basis for regular updates and maintenance, and review the completeness and accuracy of records.
Data analysis basis: Verify and validate the analysis results to ensure data reliability.
Quality management system support: As a key document of the quality management system, strengthen process management to ensure data accuracy and quality stability.