Dichromate Method CODcr Analyzer Chemical Oxygen Demand Analyzer with RS-485 Output and 30min Measurement Period for Industrial Wastewater

This method is suitable for wastewater with a chemical oxygen demand (COD) ranging from 10 to 5000 mg/L and chloride ion (Cl⁻) concentrations below 2 g/L. Based on actual user requirements, it can also be applied to wastewater with chloride ion (Cl⁻) concentrations below 20 g/L.

• Data retention during alarm or power failure.
• Touchscreen display and command input.
• Automatic residual reactant discharge and state recovery after power restoration or abnormal reset.

Unique Design: This product features a distinctive design that ensures lower failure rates, reduced maintenance requirements, minimal reagent consumption, and higher cost-effectiveness compared to similar products.

1. Selector Valve Assembly
   • Enables flexible reagent sampling timing and diverse channel configurations.
   • Minimizes dead volume for easy maintenance and extended service life.
2. Micro-Dosing Unit
   • Utilizes a visual photoelectric system for precise reagent measurement, eliminating quantitative errors caused by peristaltic pump tube wear.
   • Achieves accurate micro-dosing with 0.7 mL per dose, significantly reducing reagent usage.
3. Sample Introduction Unit
   • Employs a peristaltic pump with negative pressure suction, creating an air buffer zone between reagents and the pump tube to prevent corrosion.
   • Simplifies and enhances flexibility in reagent mixing.
4. Sealed Digestion Unit
   • Operates under high-temperature and high-pressure conditions to accelerate reactions.
   • Eliminates corrosion risks from volatile gases in open systems.
5. Reagent Tubing
   • Uses imported modified PTFE (polytetrafluoroethylene) transparent tubing with an inner diameter > 1.5 mm to minimize clogging by particulate matter in water samples.

The mixture of the water sample, potassium dichromate digestion solution, silver sulfate solution (added as a catalyst to enhance oxidation of linear aliphatic compounds), and concentrated sulfuric acid undergoes high-temperature digestion. During this process, the dichromate ions oxidize organic matter in the solution, causing a visible color change. The analyzer detects this colorimetric shift and converts it into a corresponding COD (Chemical Oxygen Demand) value for output.