(1) Working principle: The measurement method of DEK-1001 COD online water quality analyzer adopts the national standard GB11914-89 for water quality chemical oxygen demand determination (potassium dichromate method). A mixture of water sample, potassium dichromate, silver sulfate (catalyst for more complete oxidation of linear aliphatic compounds), and concentrated sulfuric acid is heated to 175 ℃ in a digestion tank. During this period, chromium ions act as oxidants and are reduced from VI valence to III valence, resulting in a change in color. The degree of color change corresponds to the content of organic compounds in the sample, and the instrument directly displays the COD of the sample through colorimetric conversion.

(2) The DEK-1001 COD online water quality analyzer has the following basic functions:

- Can set, proofread, and display time, including year, month, day, hour, and minute;

- It has an alarm function for system abnormalities such as equipment power failure, instrument leakage, and inability to import samples into the reactor, and displays the fault content. At the same time, stop running until the system is restarted;

After each measurement, the pre-treatment device, instrument pipelines, valves, and other components are automatically cleaned;

- Automatic protection for power and water outages, as well as automatic recovery for incoming and outgoing power;

- Regular cleaning and sampling functions;

Touchscreen viewing is more intuitive and easier to operate;

Automatic range switching function for three levels: (0-200) mg/L, (0-500) mg/L, and (0-1000) mg/L.