Infrared gas sensor working principle

The infrared gas sensor working principle works according to the Lambert-Beer law. The physical law is that when a beam of parallel monochromatic light passes through a uniform non-scattering light-absorbing material vertically, its absorbance is related to the concentration of the light-absorbing material and the absorbing layer. It is proportional to the thickness, and the gas concentration can be measured by measuring the attenuation of infrared light by the gas.


Infrared gas sensor technology Principle Working process: The infrared gas to be measured is continuously passed through a container of a certain length and volume, and a beam of infrared light is radiated into the side of one of the two ends of the container that can transmit light. When the wavelength of the infrared sensor is consistent with the absorption spectral line of the measured gas, the infrared energy is absorbed, and the light intensity attenuation of the infrared light after passing through the measured gas meets the Lambert-Beer law. The greater the gas concentration, the greater the attenuation of the light. At this time, the absorption of infrared is proportional to the concentration of the light-absorbing material, and the gas concentration can be measured by measuring the attenuation of the gas to the infrared light.

Infrared gas sensor working principle (1)


  1. Infrared gas sensor advantages: wide application, long service life (5 years), high sensitivity, good stability, non-toxic, less interference from the environment, independent of oxygen, etc., the infrared gas sensor has a high Excellent monitoring sensitivity, even micro-content PPB or low-concentration PPM-level gases can be accurately distinguished. It has a wide measurement range: it can generally analyze high-concentration 100% VOL gas, and can also analyze 1ppb-level gas concentration.
  2. Disadvantages of infrared gas sensors: the price is a bit expensive. Compared with electrochemistry, semiconductors and Catalytic gas sensors are much more expensive. If the accuracy requirements are not high and the budget is not high, other than PID and infrared can be considered. , the choice of other conventional detection principles.

Infrared gas sensor working principle (2)

Which gases are suitable for the Infrared gas sensor?

Infrared gas sensor is generally suitable for measuring methane, carbon dioxide, nitrogen dioxide, sulfur hexafluoride, carbon monoxide, sulfur dioxide, ammonia, ethanol, propane, ethane, cyclohexane, hexahydrobenzene, cyclopentane, propylene, propylene Nitrile, n-ethane, n-pentane, valeric acid, isobutanol, dioxane, dodecane, laughing gas, methyl bromide and other gases. In addition, the infrared gas detector is suitable for measuring most volatile organic gases, such as VOC, TVOC, VOCs, toluene, trimethylbenzene and other gases.

Application range of Infrared gas sensor

Infrared gas sensor is widely used in petrochemical industry, metallurgical industry, industrial mining, scientific research experiment, fumigation treatment, atmospheric environment monitoring, air quality detection, avionics, food processing, agriculture, medical and health and other fields.