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The chemical method residual chlorine online water quality analyzer uses the national standard method HJ 586: ‘Determination of Free and Total Chlorine in Water Quality — N,N-Diethyl-1,4-Phenylenediamine Spectrophotometric Method.’ It is capable of measuring residual and total chlorine during chlorination disinfection processes in drinking water, wastewater, and industrial circulating cooling water.
A pH buffer reagent is added to the water sample to adjust the pH to approximately 6.2–6.5. Free chlorine reacts directly with N,N-diethyl-1,4-phenylenediamine (DPD reagent) to form a red-colored compound. The absorbance of this compound is then measured at a wavelength of 510 nm to determine the free chlorine concentration.
| Product model | SH FCl-1000（DPD） |
| Measurement parameters | Residual (total) chlorine |
| Measurement method | N,N-diethyl-1,4-phenylenediamine photometry (DPD method) |
| Measurement range | 0~5mg/L |
| accuracy | ±5% or ±0.05mg/L in the range of 0-5 mg/L (whichever is greater) |
| Detection limit | 0.02mg/L |
| Lower limit of detection | 0.05mg/L |
| repeatability | ≤3% |
| resolution | 0.01mg/L |
| Measurement interval | ＜2.5min |
| Communication mode | RS485，DTU |
| Reagent usage | 0.5L indicator and 0.5L buffer solution for 30 days |
| Measurement method | Manual testing, continuous measurement, cycle measurement |
| Filtration device | With 80 Mesh Filter Set |
| Operating temperature | 5~40℃ |
| Operating humidity | < 90% RH (non-condensing) |
| Storage temperature | -15~60℃ |
| Electrical Installation Category | I. (Indoor Installation) |
| Installation method: | Wall mounted |
| power supply | AC220V±10%，50Hz±10%，<20W |
| size | 580*400*240mm |
| weight | ＜20KG（net weight） |
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