Troubleshooting of volatile organic compound monitoring system in water
1、 System Overview
The volatile organic compounds (VOCs) monitoring system in water is used to detect various volatile organic pollutants in water bodies, and its accuracy and stability are crucial for environmental monitoring. The system usually consists of a sampling unit, preprocessing unit, analytical instrument, data processing and transmission unit, etc.
2、 Common faults and troubleshooting methods
（1） Sampling process malfunction
1. Sampling pump malfunction: If the sampling volume is insufficient or there is no water sample collection, it may be due to a damaged sampling pump. Check if the power connection of the pump is normal, and if there are any abnormal sounds or overheating phenomena. If the motor of the pump burns out, a new sampling pump needs to be replaced; If the pump pipeline is blocked, the blocked part of the pipeline should be cleaned or replaced.
2. Blockage of sampling head: When there are many impurities in the water, the sampling head is prone to blockage. Remove the sampling head, rinse with clean water or use a fine needle to clear blockages to ensure smooth sampling.
（2） Preprocessing unit issues
1. Condenser malfunction: Poor condensation effect will affect subsequent analysis. Check the refrigeration system of the condenser to see if there is any refrigerant leakage. If there is any leakage, replenish the refrigerant and repair the leakage point; At the same time, clean the dust on the surface of the condenser to ensure good heat dissipation performance.
2. Failure of water removal device: Moisture entering the analytical instrument may cause measurement errors. Check if the desiccant of the water removal device is saturated, and replace it promptly if it is saturated; For membrane separation type water removal devices, check whether the membrane is damaged, and if it is damaged, replace it with a new membrane.
（3） Analysis instrument malfunction
1. Column contamination or damage: The chromatography column is a critical component for separating VOCs. If the peak shape deteriorates and the retention time drifts, it may be due to column contamination. Aging treatment can be carried out by increasing the flow rate of the carrier gas and raising the column temperature. If it still cannot be improved, the chromatographic column needs to be replaced.
2. Abnormal detector signal: The baseline of the flame ionization detector (FID) is unstable and the noise is increasing, which may be due to nozzle carbon deposition. Disassemble the nozzle, soak it in specialized cleaning solution for cleaning, and reinstall it; The response of the electron capture detector (ECD) has decreased, which may be due to moisture or contamination of the radioactive source. It needs to be handled or replaced under the guidance of professional personnel.
（4） Data processing and transmission failures
1. Software error: The data collection software displays an error message. First, check the computer system for viruses or conflicting software, perform antivirus and uninstall unnecessary programs; If the software configuration parameters are lost, import the correct configuration file again.
2. Data transmission interruption: Unstable network connection can cause data transmission failure. Check if the network cable is properly plugged in and if the router is working properly; For wireless transmission modules, check the signal strength, adjust the position or replace the antenna to enhance the signal.
3、 Key points of daily maintenance
Regular comprehensive maintenance and upkeep of the monitoring system, including cleaning various components, checking pipeline connections, calibrating instrument parameters, etc., can effectively reduce the probability of failures, ensure long-term stable operation of the system, and provide reliable data support for water quality monitoring.