A Concise Guide to Sensor Maintenance for On-Line Chlorophyll Analyzers

Regular sensor maintenance is crucial for ensuring the accuracy and reliability of on-line chlorophyll measurements. Follow these essential steps for effective sensor inspection and troubleshooting.

1. Preliminary Safety and Preparation

• Safety First: Disconnect the analyzer from power before any physical handling. Follow site-specific safety protocols for electrical equipment and water sampling.

• Initial Check: Verify the reported error or performance drift through the instrument's diagnostics or control software.

• Gather Tools: Prepare clean gloves, soft brushes, lint-free cloths, distilled or deionized water, and a mild, non-abrasive cleaner if needed.

2. Visual Inspection and Physical Cleaning

• Remove the Sensor: Isolate and carefully extract the sensor from its housing or flow cell.

• Inspect Optics: Examine the optical window (the primary sensing surface) for scratches, cracks, or heavy fouling (biofilm, algae, debris).

• Clean Gently: Using a soft brush or cloth moistened with distilled water, gently wipe the optical surface. For stubborn deposits, use a recommended mild detergent solution. Avoid scratching the window.

• Check the Flow Path: Ensure the sensor's installation area and any associated flow cell are free of blockages or air bubbles that could obstruct water contact.

3. Functional and Electronic Check

• Inspect Cables and Connectors: Look for signs of corrosion, damage, or loose connections at the sensor cable and its port on the analyzer.

• Verify Calibration: Perform a quick verification using a known standard or zero solution (e.g., filtered sample water). Significant deviation may indicate the need for a full recalibration.

• Review Logs: Check the instrument's internal data logs for unusual signals, such as consistently low light intensity readings from the internal LED or detector.

4. Calibration and Post-Maintenance Test

• Recalibrate if Necessary: After cleaning, recalibrate the sensor according to the manufacturer's procedure, typically using a zero solution and a prepared chlorophyll standard.

• Reinstall and Test: Securely reinstall the sensor, ensuring proper sealing and alignment. Restart the system and monitor the readings in a known sample or process stream to confirm stable and plausible values.

• Document: Record the maintenance actions, cleaning date, calibration data, and any observations for future reference.