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Dissolved oxygen sensor
Oxymax COS41

Dissolved oxygen sensor
Oxymax COS41 ©Endress+Hauser
Dissolved oxygen sensor
Oxymax COS41 ©Endress+Hauser

The concentration of oxygen dissolved in a liquid can be measured using the amperometric or optical measuring principles. This video shows what it is about and how these measuring principles work.

Amperometric oxygen sensor for water, wastewater and utilities

Oxymax COS41 is a reliable and accurate oxygen sensor for all kinds of water & wastewater applications. Designed for reduced maintenance and a long operating life, the sensor offers real value for money.

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  • Benefits

    • High measurement accuracy

    • Long maintenance intervals

    • Minimum calibration effort thanks to simple air calibration

  • Field of application

    Oxymax COS41 measures the dissolved oxygen concentration in:

    • Wastewater treatment plants:
      - O2 control in the aeration basin
      - Process water treatment and monitoring

    • Water works:
      - Status monitoring of drinking water (oxygen enrichment, corrosion...

Features and specifications



  • Measuring principle

    Sensor Oxygen

  • Application

    Aeration tank, river monitoring, water treatment, fish farming.

  • Characteristic

    Amperometric 2-electrode system to measure dissolved oxygen.

  • Measurement range

    0,05 - 20mg/l

  • Measuring principle

    Closed (membrane covered) amperometric 2-electrode sensor.

  • Design

    - Extreme stable membrane- Analog communication

  • Material

    Sensor body : POMMembrane cap : POM

  • Dimension

    Diameter : 40mm
    (1.56inch)Length : 220mm

  • Process temperature

    max. 50°C

  • Process pressure

    max. 10bar

  • Temperature sensor

    Integrated NTC-sensor

  • Connection

    Process connection : G1"Cable : Fixed cable or TOP68 connector

Documents / Manuals / Software

Accessories / Spare parts

Order code
    • Order code 51506784

      Accessory kit COY31-Z

      Content: COY3-F, COY31-WP, COY31-OR and COY31-PF for sensors COS31, COS41 and COS51D standard

    • Order code 50053349

      Elektrolyte COY3-F

      10 pcs. plastic ampoules, for sensors COS3/3S/COS4 and COS31/41/51D/71.

  • 2
    • Nr 2 Order code 51506976

      Set of 2x membrane cap COY31-WP

      2 pcs. ready made for sensors COS31, COS41 and COS51D standard

  • 1
    • Nr 1 Order code 51506985

      Sealing set COY31-OR

      3 pieces O-rings for sensors COS31, COS41, COS51D and COS71.

    • Order code 51506973

      Polishing foil COY31-PF

      10 pcs. for cleaning of the gold cathode for sensors COS31, COS41, COS51D and COS71.

    • Order code 51506817

      Measuring cable COK41-7

      7 m of length, ready made for sensor COS41 with TOP68 connector.

    • Order code 51506818

      Measuring cable COK41-15

      15 m of length, ready made for sensor COS41 with TOP68 connector.

  • 3
    • Order code 50003987

      Junction box VBM

      with 10 high-impedance terminals Protection class: IP65 Dimensions: 125 x 80 x 55 mm (L x W x H)

    • Order code 50081787

      COY 3-SK membrane protective basket

      for immersion of diss. oxygen sensors COS31/41/51D/61/61D in fish ponds.

    • Order code COS41-

      Oxymax W COS41

      Dissolved oxygen sensor, amperometric. 2 electrode cell. Application: Water, waste water. Measuring range: 0.05...20 mg/l. :: Compatibility, Sensor: COS4.

    • Order code COY8-

      Zero-point gel COY8

      Zero point: Verification, calibration, adjustment at zero point of oxygen and disinfection sensors ::Amperometric and optical sensors ::12, 25 and 40mm diameter ::Application in the lab, in the field