Non Dispersive InfraRed (NDIR) gas sensor is a kind of gas sensing device which based on different gas molecules' characteristic of selective absorption for near infrared spectrum, using the relationship between gas concentration and absorption intensity(Lambert-Beer Law) to identify gas components and concentrations. Compared with other types of gas sensors, such as electrochemical type, catalytic combustion type and semiconductor type, non-dispersive infrared (NDIR) gas sensors have the advantages of wide application, long service life, high sensitivity, good stability, cost-effective, low maintenance cost, online analysis and so on. It has been widely used in gas analysis, environmental protection, leakage alarm, industrial safety, medical and health, agricultural production and other fields.
1. Anti-poisoning, no carbon deposition. When CAT sensor measures some gases, it is easy to deposit carbon because of insufficient combustion, which leads to the decrease of measurement sensitivity. The IR light source and sensor are protected by glass or filter, and do not contact with gas, so there will be no combustion.
2. Oxygen is not required. NDIR is an optical sensor and does not require oxygen.
3. The measuring concentration can reach 100% v / v. Because the signal characteristics of NDIR sensor are: when there is no gas to be measured, the signal intensity is the largest, and the higher the concentration, the smaller the signal. So measuring high concentrations is easier than measuring low concentrations.
4. Excellent long-term stability and low maintenance cost. The stability of NDIR sensor depends on the light source. As long as the light source is selected, and it can be used 2 years without calibration
5. Wide temperature range. NDIR can be used in the range of - 40 ℃ to 85 ℃