Oxymax COS22

Summary

Product identification

Oxymax COS22D/COS22 digital or analog sensor for the measurement of oxygen.

Application

• Pharmaceutics and biotechnology: Process control in enzyme production, control of culture processing.
• Beverage industry
• Chemical industry
• Water treatment: Boiler feedwater, WFI (water for injection).
• Inertization
• Residual oxygen measurement in processes

Measuring principle

Oxygen molecules diffuse through a membrane and are reduced at the cathode to hydroxide ions (OH⁻). At the anode, silver is oxidized to silver ions (Ag⁺), forming a silver halide layer. A current proportional to the oxygen content flows and is converted by the transmitter.

Measuring system components

A complete measuring system comprises:

• An Oxymax COS22 or Oxymax COS22D oxygen sensor.
• A transmitter (Liquiline CM44x, Liquiline CM42, Liquisys COM2x3).
• An appropriate measuring cable (CYK10 for COS22D, COK21 for COS22).
• Optional: an assembly (e.g., CPA442, CPA240, or CPA875).

Measuring ranges

COS22/22D-*1 (Standard sensor)

• Optimum operational range: 0.01 to 20 mg/l, 0 to 200 % SAT, 0 to 400 hPa, 0 to 40 Vol%.
• Full range: 0.01 to 60 mg/l, 0 to 600 % SAT, 0 to 1200 hPa, 0 to 100 Vol%.

COS22/22D-*3 and COS22D-*4 (Trace sensor)

• Optimum operational range: 0.001 to 2 mg/l, 0 to 20 % SAT, 0 to 40 hPa, 0 to 4 Vol%.
• Full range: 0.001 to 10 mg/l, 0 to 120 % SAT, 0 to 250 hPa, 0 to 25 Vol%.

Performance characteristics

• Response time (t98): < 60 s (from air to nitrogen at reference conditions).
• Signal current in air:
  • Standard sensor (*-1): 40 to 100 nA.
  • Trace sensor (*-3, *-4): 210 to 451 nA.
• Zero current:
  • Standard sensor (*-1): < 0.1 % of signal current in air.
  • Trace sensor (*-3, *-4): < 0.03 % of signal current in air.
• Measured value resolution:
  • Standard sensor (*-1): 10 ppb (aqueous), 0.2 hPa or 0.02 Vol% (gaseous).
  • Trace sensor (*-3, *-4): 1 ppb (aqueous), 0.02 hPa or 0.002 Vol% (gaseous).
• Maximum measured error: ≤ ±1 % of measuring range + 10 ppb (standard), ≤ ±1 % of measuring range + 1 ppb (trace) at reference conditions.
• Long-term drift: < 4 % per month (reference conditions); ≤ 1 % per month (operation with reduced oxygen concentration).
• Polarization time:
  • Standard sensor (*-1): < 30 min for 98% signal, 2 h for 100%.
  • Trace sensor (*-3, *-4): < 3 h for 98% signal, 12 h for 100%.
• Intrinsic oxygen consumption:
  • Standard sensor (*-1): Approx. 20 ng/h in air at 25 °C.
  • Trace sensor (*-3, *-4): Approx. 100 ng/h in air at 25 °C.
• Operating time of the electrolyte:
  • Standard sensor (*-1): > 1.5 years.
  • Trace sensor (*-3, *-4): > 3 months.

Temperature compensation

• Compensation of membrane properties is performed in the transmitter between -5 and 90 °C (23 to 194 °F). Extrapolation above 90 °C.
• Measured variable as partial pressure or Vol%: -5 to 90 °C (23 to 194 °F).
• Measured variable as concentration: 0 to 80 °C (32 to 176 °F).
• Measured variable as saturation: -5 to 90 °C (23 to 194 °F).

Installation

• Installation in a suitable assembly is required. Do not install the sensor suspended from the cable.
• Permitted angle of installation: 10° to 170°. Recommended angle: 45°. Do not install overhead.

Environmental limits

• Ambient temperature range:
  • *-1 /3: -5 to +135 °C (23 to 275 °F), non-freezing.
  • *-4: -5 to +50 °C (23 to 120 °F), non-freezing.
• Storage temperature: –5 to +50 °C (20 to 120 °F) at 95% relative humidity, non-condensing. Store with watering cap filled with tap water.
• Degree of protection: IP 68.

Process limits

• Process temperature:
  • *-1 /3: -5 to +135 °C (23 to 275 °F), non-freezing.
  • *-4: -5 to +80 °C (23 to 180 °F), non-freezing.
• Process pressure: Ambient pressure ... 12 bar (... 174 psi) absolute.
• Minimum flow:
  • Standard sensor (*-1): 0.02 m/s.
  • Trace sensor (*-3, *-4): 0.1 m/s.

Chemical resistance

Chemically resistant to:

• Diluted acids and alkalis.
• Hot water and superheated steam up to max. 135 °C (275 °F).
• CO₂ up to 100 % (only with trace sensor COS22/22D-*3).

Note: Hydrogen sulfide and ammonia shorten the operating life of the sensor.

Cross-sensitivity

• Molecular hydrogen causes false low readings with COS22/22D-*1/3. No cross-interference from hydrogen with the COS22D-*4 version.

Sterilization and cleaning

• CIP compatibility: Yes (COS22/22D-*1/3).
• SIP compatibility: Yes, max. 140 °C (284 °F) (COS22/22D-*1/3).
• Autoclavability: Yes, max. 140 °C (284 °F), max. 30 min. (COS22/22D-*1/3).

Mechanical construction

• Process connection: Pg 13.5.
• Dimensions: See diagrams (lengths vary: 120 / 225 / 360 / 420 mm).
• Weight: 0.2 kg (0.44 lbs) to 0.7 kg (1.54 lbs) depending on design.
• Materials:
  • Sensor shaft: Stainless steel 1.4435 (AISI 316L), Titanium, Alloy C22.
  • Electrode combination: Silver / platinum (-1/3); Silver / gold (-4).
  • Process seal: VITON (FDA-compliant), Perfluoroelastomer.
  • Membrane: Silicone (FDA-compliant), PTFE, steel mesh.

Electrolyte

• *COS22/22D-1 (standard sensor): Slightly alkaline electrolyte.
• *COS22/22D-3 (trace sensor): Neutral electrolyte.
• *COS22D-4 (trace sensor, gold): Slightly alkaline electrolyte.

Certificates and approvals

• CE mark.
• Ex approvals (ATEX, IECEx, FM/CSA, NEPSI, TIIS) available for specific versions.
• Manufacturer declaration of FDA compatibility.
• Material test certificate 3.1 (in accordance with EN10204) available depending on version.
• EHEDG Type EL Class I.

Scope of delivery

• Oxygen sensor with watering cap.
• Electrolyte (1 bottle, 10 ml).
• Tool to push out the membrane body.
• Brief Operating Instructions.

Disclaimer: Extraction may miss figures, footnotes, or revisions; contractual data must match the OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror