There are many different methods for gas concentration detection, some of which are widely used are as follows:
(1) Electrochemical method: Use of electrical parameters such as electrical resistance or conductivity of materials to change with the change of gas concentration to make gas sensors. Insert the anode and cathode electrodes into the electrolyte at the same time, the electrons are transferred through the reaction, and then the current changes, and the related information of the reaction concentration is generated.
(2) Solid gas method: Use a heater to heat metal oxides prepared into beads or flakes. Oxygen accumulates on their surfaces, changing the resistance value and reacting to changes in concentration information.
(3) Catalytic combustible gas: The resistance value changes with the temperature change on the screw ring, reflecting the relevant concentration information, destroying the balance of the electric bridge, and showing it in the form of electrical signals.
(4) Infrared absorption method: Based on Lambert Beer's law, the concentration-related information is expressed by the gas characteristic absorption method.
Infrared mixed gas detection has been widely used in many fields, including atmospheric chemical analysis, industrial process control, agricultural production management, urban environmental quality detection, life science research, etc.