CO2 Sensor from Gas Sensing Solutions Increases Diver Safety

Recreational diving is enjoyed by people around the world and diving with rebreather equipment is booming. The CO2 sensor kit. Source: Gas Sensing SolutionsRebreather technology enables divers to dive deeper and longer than previously thought possible without scuba equipment. These systems recirculate air, remove carbon dioxide and top up the oxygen level.

Carbon dioxide removal is performed chemically by passing the exhaled gas through a scrubber containing soda lime. The capability of the scrubber depends on the user refilling with the correct soda lime at the correct time, and it can be fatal to get this action wrong. AP Diving, a manufacturer of rebreathers, has addressed this problem with a custom CO₂ sensor developed by Gas Sensing Solutions (GSS).

The solution is to fit the rebreather with a CO₂ sensor unit. This gives a vital -- and potentially life-saving - early warning of a rise in CO₂ levels. GSS sensors are the only ones that can be run off batteries, which makes this solution for diving rebreathers possible. In this case, the GSS ultra-low power, CozIR™ Wide Range CO₂ sensor is used.

The GSS sensor uses very little power and turns on almost instantly so that it can be incorporated in the normal start up sequence of battery and component tests. In addition, it also measures the partial pressure of CO₂ to give warnings as low as 3 mbar - which is only 0.025 percent at 100m.

CO₂ sensors work by measuring how much light is absorbed by CO₂ molecules in the 4.2 and 4.4 microns range as it passes through the sample gases, which is called Non-Dispersive Infra Red (NDIR) absorption. The amount of absorption indicates how much of the gas is present. GSS developed LEDs that are specifically tuned to emit at these wavelengths. These LEDs use very little power and turn on almost instantly, enabling sensor readings to be made in less than a second.