Detection working principle of combustible gas alarms

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A combustible gas alarm consists of a combustible gas detector and an alarm controller. The detector is installed in areas where there is a risk of gas leakage; its key component is the gas sensor. Combustible gas alarms use catalytic combustion or semiconductor gas sensors, while toxic gas alarms employ electrochemical, semiconductor, and infrared sensors. The alarm controller is installed in the control room or duty room of a secure location. The working principle of the detector is that the gas sensor causes changes in resistance depending on different gas concentrations during heating, direct combustion, and electrochemical reactions, thereby generating different voltage signals. The alarm controller amplifies the electrical signals collected by the detectors, and through computation and analysis, it outputs audible and visual alarm signals as well as control signals for interlocking operations. When there are combustible gases or volatile combustible vapors in the air, the detector’s signal is transmitted immediately via cable to the alarm controller, which displays the gas concentration. When this concentration exceeds the set alarm threshold, the alarm device emits audible and visual alerts and sends out control signals to activate devices such as fans and solenoid valves in order to eliminate the hazard, thereby ensuring production safety and personal safety and preventing accidents from occurring. It is widely used in industries such as petroleum, gas, chemicals, and oil depots where flammable gas leaks may occur.