Gas detection with infrared absorption

Functionality

The light is absorbed at the wavelength of the absorption band. This means that energy is taken out of a light beam. This energy is used to trigger the atoms of a molecule to vibrate. Two light beams are used in an infrared gas sensor: One measuring beam with a wavelength of 3.4 μm, and a second with a different wavelength as a reference. Both beams are directed onto light detectors. If the measuring beam suddenly receives less energy compared to the reference beam, there must be a gas present taking energy out of the measuring beam. Compur uses infrared absorption for the sensor heads of the Statox series. This measuring principle can also be used to detect inert gases which could not be measured using other methods, because there is no oxygen present (which would be required by a catalytic sensor for example) or because corrosive products would be produced during oxidation that would poison a catalytic sensor.

Advantages of infrared technology

There is no risk of sensor poisoning, which means that the intervals for maintenance and calibration can be longer. An also important advantage is that no oxygen is required for measurement.

Another advantage of infrared measurement technology is that the failure of the radiation source or a detector will be detected as total absorption and thus trigger an alarm. This means that a fault never goes unnoticed.

Safe infrared technology from Compur

The sensors of the Statox devices, which work with infrared absorption, are particularly suitable for hydrocarbons such as those found in the chemical and petrochemical industries. Their long lifetime and little request for maintenance help to save cost without having to compromise on safety in gas detection. Compur has been developing and producing gas detection and warning devices for more than fifty years, and these have become well established on the market. These include, in particular, the Statox series of detectors.