Electrochemical Oxygen Sensors (Galvanic sensor)
Ambient temperature electrochemical sensors, (often called galvanic sensors), are designed around a small cylinder which is sealed on one side using the sample under test.
The cylinder includes two electrodes immersed in potassium hydroxide, though other aqueous electrolytes can be used. As the oxygen diffuses through the sample it produces positively charge hydroxyl ions at the cathode. These hydroxyl ions migrate to the anode where they are re-oxidised, generating a current that is proportional to the oxygen concentration
Measuring this current produces results that can be accurate in the Parts Per Million (PPM) range.
Unfortunately, the lifetime of these sensors can be seriously reduced if they are applied to gases containing acids - such as hydrogen sulphide, sulphur dioxide or hydrogen chloride, unless the offending gas constituent is scrubbed prior to analysis. The sensors are also susceptible to over pressurization and a pressure regulator / control valve is recommended.
At Versaperm we are not tied to any specific sensor types or manufacturer and so we can always select exactly the right sensor for an application. Versaperm is a world technology leader in the measurement of gas permeability. We offer not only instruments but also comprehensive testing and consultancy services.