Electrochemical chlorine sensor CS4

for water treatmentfor process controlfor wastewater treatment plants

Product overview
Manufactured in Germany, the CS4 free chlorine sensor uses a microporous hydrophilic osmotic membrane to reduce pH dependence and resist chemical interference from surfactants. The sensor delivers fast response (T90 ≈ 2 min), stable readings and low maintenance, providing accurate residual chlorine data across varied water qualities including tap water, pools, drinking/service/process water, wastewater and seawater.

Special features

• Reduced dependence on pH
• Tolerant to surfactants and chemical interference
• Low maintenance; zero-point adjustment not required
• Operates at low conductivity (from 10 μS/cm)

Applications

• Tap water
• Swimming pools
• Drinking, service and process water
• Medical wastewater and sewage/waste water treatment
• Fruit and vegetable disinfection
• Seawater and high-salinity water
• Pipeline disinfection
• Industrial water treatment

Ambient conditions

• Max. measuring water temperature: 45 °C
• Max. ambient temperature: 55 °C
• Max. pressure: 3 bar
• Minimum conductivity: 10 μS/cm

Technical data (table)
Measurement parameter: Free chlorine (reduced pH dependence)
Measuring ranges / resolution: 0.005…2.000 ppm (0.001 ppm); 0.05…20.00 ppm (0.01 ppm); 0.5…200.0 ppm (0.1 ppm)
Response time: T90 ≈ 2 minutes
Measuring water temperature: 0 … +45 °C (no ice crystals in the measuring water)
Ambient temperature: 0 … +55 °C
Temperature compensation: Automatic (integrated temperature sensor); avoid sudden temperature changes
Max. allowed working pressure: operation with retaining ring in FLC: -0.5 bar (no pressure impulses/vibrations); with retaining ring in FLC: -3 bar (no pressure surges/vibrations)
Flow rate (face velocity): approx. 15–30 l/h (33–66 cm/s) in flow cell (small flow dependence)
pH range: pH 4 – pH 9 (reduced dependence on pH value)
Conductivity: 10 μS/cm – 50 mS/cm (including sea water)
Run-in time: First start-up approx. 2 h
Zero point adjustment: Not necessary
Protection class: 5-pole M12 plug-on flange: IP68; 2-pole terminal with mA-hood: IP65
Material: Microporous hydrophilic membrane, PVC-U, stainless steel 1.4571

Technical specifications

• Model: CS4
• Parameter: Free chlorine
• Measuring ranges / resolution: 0.005–2.000 ppm (0.001 ppm); 0.05–20.00 ppm (0.01 ppm); 0.5–200.0 ppm (0.1 ppm)
• Response time: T90 ≈ 2 minutes
• Measuring water temperature: 0 … +45 °C
• Ambient temperature: 0 … +55 °C
• Temperature compensation: Automatic (integrated sensor)
• Flow rate: approx. 15–30 l/h (33–66 cm/s) in flow cell
• pH range: 4 – 9
• Conductivity: 10 μS/cm – 50 mS/cm
• Run-in time (first start-up): approx. 2 h
• Zero point adjustment: Not necessary
• Protection: IP68 (M12) / IP65 (2‑pole terminal)
• Materials: Microporous hydrophilic membrane; PVC-U; stainless steel 1.4571