Three well-known gas detectors are compared.
1. Analysis of the characteristics of semiconductor sensors
Semiconductor sensor gas detectors are manufactured based on changes in resistance. The resistance of tin dioxide will decrease rapidly when it encounters alcohol gas at high temperature, and an alcohol sensor is prepared based on this principle. This sensor has the characteristics of low cost and is very suitable for detecting civil gas. Environmental factors have a relatively large impact on semiconductor sensor gas detectors, resulting in unstable detection results. Moreover, the output parameters of this kind of gas detector cannot be determined, so it is not suitable for places where accurate measurement is required.
2. Analysis of the characteristics of combustion sensors
The combustion sensor prepares a high-temperature-resistant catalyst layer on the surface of the platinum resistor. When the temperature is sufficient, the flammable gas will be catalyzed and burned. The combustion will increase the temperature of the platinum resistor and reflect the concentration of the flammable gas through the resistance. The detection range of the catalytic combustion sensor gas detector only includes flammable gases, and the sensor will not react if the gas cannot be burned. The catalytic combustion gas detector responds accurately and quickly and has a long service life.
3. Analysis of the types of electrochemical sensors
A considerable part of its flammable, toxic and harmful gases are electrochemically active and can be electrochemically oxidized or reduced. The principle of the original battery type gas sensor is roughly the same as that of the dry battery. At present, the detection of toxic and harmful gases mainly relies on constant potential electrolytic cell type gas sensors. Concentration battery type gas sensor can form concentration electromotive force related to gas concentration and detect gas concentration, such as oxygen sensor for automobiles.
