Principle of use of electrochemical gas detectors
A significant portion of flammable, toxic and hazardous gases are electrochemically active and can be electrochemically oxidised or reduced. Using these reactions, gas components can be distinguished and gas concentrations can be detected. Electrochemical gas sensors are divided into many subcategories:
(1), the original battery-type gas detector (also known as: Gavony battery-type gas sensors, also known as fuel cell-type gas sensors, also known as spontaneous battery-type gas sensors), the principle of their line with the dry cell battery we use, only, the battery's carbon and manganese electrodes were replaced by gas electrodes. In the case of an oxygen sensor, for example, oxygen is reduced at the cathode and electrons flow through the ammeter to the anode, where the lead metal is oxidised. The magnitude of the current is directly related to the concentration of oxygen. This type of sensor can effectively detect oxygen, sulphur dioxide, chlorine and so on.
(2), constant potential electrolytic cell type gas detector, this sensor is used to detect reducing gases very effectively, its principle is not the same as the primary cell type sensor, its electrochemical reaction occurs under the compulsion of the current, it is a real sensor of Coulomb analysis. This sensor has been successfully used for: carbon monoxide, hydrogen sulfide, hydrogen, ammonia, hydrazine, and other gases in the detection, is currently the mainstream of toxic and hazardous gas detection sensor.
(3), concentration difference battery type gas detector, with electrochemical activity of the gas on both sides of the electrochemical battery, will spontaneously form a concentration difference electric potential, the magnitude of the electric potential is related to the concentration of the gas, the success of such sensors is the automotive oxygen sensors, solid electrolyte type carbon dioxide sensor.
(4), limit current type gas detector, there is a measurement of oxygen concentration of the sensor using electrochemical cell in the limit current and carrier concentration related to the principle of preparation of oxygen (gas) concentration sensor, used for automotive oxygen detection, and oxygen concentration detection in steel water.
