COD stands for Chemical Oxygen Demand, which is a chemical method to measure the amount of reducing substances that need to be oxidized in a water sample. The oxygen equivalent of substances (generally organic matter) that can be oxidized by strong oxidants in wastewater, wastewater treatment plant effluents, and polluted water. The potassium dichromate method is one of the standard COD determination methods.
The COD analyzer first lifts the water sample from the discharge open channel to the inlet fine filter sampling cup by the self-priming pump and then lifts the water sample into the reaction chamber by the inlet peristaltic pump.
Then, potassium dichromate, silver sulfate mono sulfate, and distilled water are respectively added into the reaction chamber by the peristaltic pump in sequence.
After the sample injection, start microwave heating for 5 minutes (the heating time can be set and modified by yourself), after the heating is completed, inject distilled water to dilute and cool to room temperature, and then the air pump will blow the mixed solution to the measurement chamber for measurement, and automatically calculate and display measurement results.
Finally, the mixed solution is discharged by the pneumatic pump and the pipeline is purged to enter the next measurement cycle. The whole cycle process is controlled by PLC and is carried out automatically.
During operation, the peristaltic pump has the following advantages:
1) Easy maintenance: no need to disassemble or flush, just replace the pump tube, you can change from one type of liquid to another, in a short time and high efficiency.
2) High precision: It has a calibration function and supports multiple calibrations, thereby reducing the flow rate error to ensure flow accuracy. In addition, it also has a suction function, which can set the suction speed and suction angle to prevent the liquid from flowing back.
3) No pollution: When transferring liquid, the liquid only contacts with the pump tube and does not contact other parts of the pump.
Recommend OEM216-WP310 peristaltic pump applied in the COD instrument
- Compact size, Max flow up to 1100ml/min
-Transparent flip cover design for easy viewing of the hose
-The pump head is made of PPS+PS material, corrosion resistance, and high strength
