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 | 1 month per session; ~30min per maintenance
|
| 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) |
