Within the global industrial safety and civil protection sectors, combustible gas detectors serve as core equipment for preventing explosion incidents. Based on varying technical principles, application scenarios, and detection targets, these devices can be categorised into multiple types. Below, Yiyuntian Eranntex provides an international perspective, analysing mainstream classification methods and their technical characteristics.

　　I. Classification by Detection Principle: Catalytic Combustion Type and Infrared Optical Type

　　1. Catalytic Combustion Detectors

　　Catalytic combustion detectors operate based on the principle of platinum wire resistance variation. When combustible gases (such as propane or methane) enter the detection chamber, they undergo flameless combustion on the platinum wire surface. The resulting heat increases the wire's temperature, altering its resistivity. The instrument calculates gas concentration by monitoring this resistance change, making it suitable for detecting alkane gases in conventional environments.

　　Technical Advantages:

　　Low cost, simple maintenance, service life of 3-5 years

　　Strong resistance to interference, unaffected by humidity or dust

　　Short response time (<15 seconds), ideal for rapid leak detection

　　2. Infrared Optical Detectors

　　Infrared optical detectors utilise the absorption characteristics of gas molecules towards specific infrared wavelengths. By emitting infrared light and analysing reflected intensity changes, they precisely measure concentrations of hydrocarbons such as propane and ethylene.

　　Technical Advantages:

　　Strong resistance to poisoning, suitable for environments containing catalytic poisons like silicon and sulphur

　　Maintenance-free design with sensor lifespans exceeding 5 years

　　Stable operation in oxygen-deficient environments (e.g., confined spaces)

　　II. Classification by Application Scenario: Domestic and Industrial Models

　　1. Domestic Combustible Gas Detectors

　　Designed for households and small commercial premises, these typically employ semiconductor or catalytic combustion sensors to detect natural gas and liquefied petroleum gas leaks.

　　Technical Features:

　　Compact size for straightforward installation (e.g., under kitchen ceilings)

　　220V mains power supply with audible and visual alarm functions

　　Detection range: 10-15 square metres; lower sensitivity (>5% LEL alarm threshold)

　　2. Industrial Combustible Gas Detectors

　　Industrial detectors feature explosion-proof designs for hazardous environments like petrochemical plants and metallurgy, detecting over 60 industrial gases including propane and hydrogen.

　　Technical Features:

　　Die-cast aluminium housing, IP65 protection rating

　　4-20mA analogue signal + RS-485 digital output

　　Supports interlocking control with solenoid valves and exhaust fans

　　Detection range: 25-30 square metres, sensitivity up to 0.5% LEL

　　III. Functional Classification: Portable and Multi-Gas Detectors

　　1. Portable Combustible Gas Detectors

　　Suitable for on-site inspections and confined space operations, available in diffusion-type and pump-aspiration models.

　　Technical Features:

　　Lithium-ion battery power, 12-15 hours continuous operation

　　Pump-aspiration sampling response time <5 seconds

　　Data logging capability, stores 100,000 data sets

　　2. Multi-Gas Detectors

　　Multi-gas detectors simultaneously monitor combustible gases, toxic gases (e.g., carbon monoxide, hydrogen sulphide), and oxygen concentration, suitable for complex industrial environments.

　　Technical Features:

　　Combination of electrochemical sensors and catalytic combustion sensors

　　Supports simultaneous detection of 1-30 gases

　　Equipped with GPS positioning and wireless transmission capabilities

　　From domestic kitchens to multinational petrochemical projects, the technological classification and functional expansion of combustible gas detectors consistently evolve around safety requirements. For users, selecting equipment certified to UL, CE, or IEC standards, alongside adhering to regular calibration and correct installation protocols, remains paramount for ensuring the safe handling of propane and other combustible gases. With the proliferation of intelligent early-warning systems, global industrial safety is advancing towards a more efficient era of proactive protection.