Glossary · Sensors and measurement
Oxygen sensor
Also known as: O2 sensor, Oxygen analyzer
German: Sauerstoffsensor
In process analytics, an oxygen sensor is a sensor that measures the oxygen concentration in gases or the dissolved oxygen in liquids, using principles such as zirconia, paramagnetic, electrochemical, optical or laser absorption measurement.
- Sensors
- Process industry
In one sentence
An oxygen sensor measures oxygen in gases or dissolved in liquids, used for combustion control, inerting, water treatment and gas monitoring.
Example
An optical dissolved-oxygen sensor in the aeration basin of a wastewater plant controls the blowers to save energy.
How it applies
- Engineering: The principle depends on the application: zirconia probes for flue gas, paramagnetic analyzers for process gases, electrochemical cells for ambient monitoring and optical sensors for dissolved oxygen.
- Operation: In combustion control, oxygen measurement optimizes efficiency and emissions. In inerting, it monitors that oxygen stays below a limit.
- Safety: When oxygen measurement is part of a protective function, such as inerting or monitoring oxygen deficiency in confined spaces, the sensor and function must be designed and tested for that role; a process analyzer alone is not enough.
- Documentation: Specify calibration gases or procedures, sensor lifetime for electrochemical cells and response time in the maintenance manual.
Oxygen in gases vs. dissolved oxygen
Oxygen in gases is given in volume percent or ppm; dissolved oxygen in liquids is given in mg/l or percent saturation. The units and sensors differ, so name the quantity explicitly.