PH electrochemical electrode MST1

plasticmetalfor water

Overview
The MST1 chlorite sensor is manufactured in Germany and uses a membrane-covered amperometric potentiostatic three-electrode system to accurately measure chlorite concentrations. Designed for drinking water, swimming-pool water, service water and process water. Compatible with acid/chlorite and chlorine/chlorite dioxide production methods. Features automatic temperature compensation, IP65/IP68 protection options and multiple output versions. Resistant to interference from chlorine dioxide, chlorine and chlorate; Mn2+, nitrite and some corrosion inhibitors may affect readings. EMC-tested and RoHS-compliant.

Special features

• Membrane-covered microporous hydrophilic membrane system (mechanically robust)
• Tolerates surfactants
• No cross-sensitivity to chlorine dioxide, chlorine and chlorate
• High chemical tolerance
• Automatic temperature compensation by integrated temperature sensor

Applications
Swimming-pool water, drinking water, service water and process water; suitable for water disinfection control and general water treatment applications.

Process conditions

• Measuring water temperature: 0 … +40 °C (no ice crystals in the measuring water)
• Ambient temperature: 0 … +55 °C
• Max. temperature (typical): 40 °C
• Max. pressure: up to 5 bar (see mounting/retaining-ring conditions); avoid pressure surges and vibrations
• Flow rate (face velocity): approx. 15–30 L/h in flow cell (small flow-rate dependence)
• pH range: pH 6 – pH 9
• First start-up / run-in time: approx. 24 h
• Zero point adjustment: not necessary
• Protection class: IP68 (5-pole M12 plug-on flange) or IP65 (2-pole terminal with mA-hood) depending on connection version
• Materials: microporous hydrophilic membrane, PVC, PEEK, stainless steel

Technical specification
Measurement parameter: Chlorite
Measuring ranges / resolution: 0.005 … 2.000 ppm (resolution 0.001 ppm); 0.05 … 2.00 ppm (resolution 0.01 ppm)
Response time: T90 ≈ 1 min.
Measuring water temperature: 0 … +40 °C (no ice crystals in the measuring water)
Ambient temperature: 0 … +55 °C
Temperature compensation: Automatic, by integrated temperature sensor; max. change in temperature: 0.3 °C per minute (avoid sudden changes)
Max. allowed working pressure: Operation with retaining ring in FLC: -0.5 bar (no pressure impulses/vibrations); for other retaining ring variants consult mounting instructions (avoid pressure surges)
Flow rate (face velocity): approx. 15–30 L/h in flow cell (small flow-rate dependence)
pH range: pH 6 – pH 9
Run-in time: First start-up approx. 24 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, PEEK, stainless steel

Technical specifications (summary)

• Model: MST1
• Measurement target: Chlorite
• Measuring ranges: 0.005–2.000 ppm (resolution 0.001 ppm) and 0.05–2.00 ppm (resolution 0.01 ppm)
• Response time: T90 ≈ 1 min
• Temperature compensation: Integrated, automatic
• Operating temperature (measuring water): 0–40 °C
• Ambient temperature: 0–55 °C
• pH operating range: 6–9
• Max. working pressure: up to 5 bar (application- and mounting-dependent)
• Protection ratings: IP65 / IP68 depending on connector
• Materials: Membrane (microporous hydrophilic), PVC, PEEK, stainless steel
• Compliance: EMC-tested, RoHS-compliant