Detection Principle
Multi-gas detectors use multiple built-in sensors to simultaneously monitor various toxic, flammable, or combustible gases. Common sensing technologies include:
Electrochemical Sensors – Used for toxic gases such as CO, H₂S, or NO₂. Gas reacts with electrodes to generate a current proportional to the gas concentration.
Catalytic Combustion Sensors – Used for combustible gases such as CH₄ or C₃H₈. Gas burns on a catalyst surface, generating heat, which is detected by a thermocouple and converted into a signal.
Semiconductor / Metal Oxide Sensors (MOS) – Suitable for multiple flammable or volatile gases. Gas adsorption changes the resistance of the semiconductor, which is used to calculate gas concentration.
Non-Dispersive Infrared (NDIR) Sensors – Used for gases like CO₂, measuring gas concentration based on absorption of infrared light at specific wavelengths.
Signal Processing and Display
Sensors convert chemical reactions or physical changes into electrical signals. The detector’s microprocessor amplifies, calibrates, and processes these signals, providing real-time gas concentration readings on the display and triggering alarms when thresholds are exceeded.
Simultaneous Multi-Gas Monitoring
Multi-gas detectors can collect data from all sensors simultaneously, allowing independent monitoring of each gas. For example, a single device can monitor O₂ (oxygen deficiency), CO (carbon monoxide), H₂S (hydrogen sulfide), and combustible gases at the same time.
Alarm and Safety Features
Visual, audible, and vibration alarms activate when gas concentrations exceed preset limits.
Many detectors also support data logging, download, and remote monitoring for safety management and risk analysis.
Industrial Environments
Petrochemical plants, natural gas facilities, and chemical production/storage
Coal mines, metal processing, and smelting industries
Pharmaceutical, food processing, and electronics manufacturing
Environmental and Safety Monitoring
Industrial exhaust and emissions monitoring
Indoor air quality assessment
Laboratory and cleanroom safety monitoring
Emergency Response & Personal Protection
Firefighting, rescue, and hazardous material incident monitoring
Gas leak detection in confined spaces
Safety inspections in enclosed or high-risk areas
Buildings & Public Spaces
Underground parking lots, tunnels, and subway stations
Commercial buildings and public facilities for toxic gas protection
Typical Gases Monitored
Oxygen (O₂) — oxygen deficiency or enrichment
Carbon Monoxide (CO) — toxic gas monitoring
Hydrogen Sulfide (H₂S) — corrosive and toxic gas
Combustible gases (LEL, Methane, Propane, etc.) — explosion risk
Volatile Organic Compounds (VOCs) — environmental and health hazards
