Why Electrochemical O2 sensor for Scuba Diving

Electrochemical O2 sensors are the best choice for scuba diving due to their excellent stability at elevated O2 levels, accuracy, relatively small size, and lower cost.

In electrochemical O2 sensors, oxygen is reduced at the cathode with simultaneous oxidation of anode (typically lead, Pb), the flow of current between anode and cathode is proportional to the partial pressure of O2 in a gas stream. Sensors are calibrated against a known standard before diving. Theoretically, these sensors should continue to function without losing signal strength but in reality, some sensors tend to drift after a few hours of dive due to “current-limiting” behavior. AST found that the geometry of Pb anode, its placement inside the sensor body, and electrolyte composition play a major role in sensor stability during dive. AST uses a unique anode structure in the diving O2 sensors and its placement inside of the sensor affords maximum active surface of the anode for oxygen reduction process. This arrangement diminishes the sensor’s current-limiting behavior, and it continues to function at elevated O2 levels assuring diver’s safety. In certain O2 sensor designs, condensation of moisture also contributes to loss of signal output and forces the diver to abandon the dive after a few hours of dive. AST diving O2 sensors with unique clamping material and mechanism in front of sensing surface prevents moisture condensation and the sensor continues to hold its signal output through a dive.