Nanjing Juge Environmental Technology Co., Ltd.
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Online CODcr COD Water Quality Analyzer Potassium Dichromate Oxidation Spectrophotometric Method Monitor
>>Overview
Chemical Oxygen Demand (COD) refers to the mass concentration of oxygen consumed by strong oxidants under specific conditions to oxidize organic and inorganic reducing substances in water samples. COD is a critical indicator reflecting the extent of water pollution caused by organic and inorganic reducing substances.
This analyzer is designed for long-term, unattended, automatic, and continuous operation based on field configurations. It is widely applicable to scenarios such as industrial pollution source wastewater discharge, industrial process wastewater, industrial wastewater treatment plant effluent, and municipal sewage treatment plant effluent. Depending on the complexity of on-site testing conditions, optional preprocessing systems can be integrated to ensure reliable testing processes, accurate results, and full compliance with diverse on-site requirements.
>>Features
A mixture of the water sample, potassium dichromate digestion solution, silver sulfate solution (added as a catalyst to enhance oxidation efficiency for straight-chain aliphatic compounds), and concentrated sulfuric acid is heated to 165°C. After the dichromate ions oxidize organic substances in the solution, a color change occurs. The analyzer detects this colorimetric change, converts it into a COD value output. The amount of dichromate ions consumed corresponds to the quantity of oxidizable organic matter, which is quantified as the COD value.
>>Technical Parameter
| Test Method |
Potassium dichromate oxidation spectrophotometric method |
| Measuring Range |
0~5000mg/L (segmented measurement, expandable) |
|
Indication Error |
20% range standard solution: ≤±10% 50% range standard solution: ≤±8% 80% range standard solution: ≤±5% |
| Quantitative Lower Limit |
≤15mg/L |
| Repeatability |
≤5% |
|
Drift (24h) |
Low concentration drift: ±5mg/L High concentration drift: ≤5% |
| Masking Capacity |
Up to 20,000mg/L Cl⁻ |
| Measurement Time |
<50min (digestion time adjustable) |
| Measurement Modes |
Adjustable time interval, fixed time point, or triggered measurement |
|
Calibration Modes |
Automatic calibration (1~99 days adjustable) Manual calibration based on actual water samples |
|
Maintenance Cycle |
|
| Human-Machine Interface |
Touchscreen display and command input |
|
Self-Diagnosis & Protection |
Self-diagnoses operational status; retains data during anomalies/power outages Automatically clears residual reactants and resumes operation after reset/power recovery |
| Data Storage |
5-year data capacity |
| Input Interface |
Digital input |
|
Output Interfaces |
1× RS232, 1× RS485 2× 4~20mA analog outputs |
|
Operating Environment |
Indoor use; recommended temperature: 5~28℃, humidity ≤90% (non-condensing) |
|
Power Supply |
Voltage: AC 220±10% V Frequency: 50±0.5 Hz Power: ≤150W (excluding sampling pump) |
|
Dimensions |
520H × 370W × 265D (mm) |