The gas detector is a kind of instrument for monitoring the gas leakage content, including portable gas detector, hand-held gas detector, fixed gas detector, online gas detector, etc. The gas sensor is mainly used to monitor the type of gas stored in the environment. The gas sensor is used to monitor the composition and content of the gas.
It is generally believed that the concept of gas sensor is based on the classification of monitoring targets. In other words, any sensor used to monitor the composition and content of gas is called a gas sensor, whether it is physical or chemical. For example, the sensor that monitors the gas flow is not regarded as a gas sensor, but the thermal conductivity gas analyzer belongs to the gas sensor, although these sometimes use the same monitoring principle.

Combustion type
This kind of sensor is made of heat-resistant catalyst layer on the surface of platinum resistance. At a certain temperature, combustible gas will burn on its surface. Combustion will make platinum resistance temperature rise and resistance change. The change value is a function of combustible gas content.

Semiconductor type
It is produced by using the principle that the conductivity of some metal oxide semiconductor materials changes with the change of the environmental gas composition at a certain temperature. For example, the alcohol sensor is made based on the principle that when tin dioxide meets alcohol gas at high temperature, the resistance will decrease sharply.

LEL
"LEL" refers to the lower explosive limit. The minimum content of combustible gas in the air when it meets an open flame is called the lower explosive limit -% LEL for short. English: LowerExplorationLimited.
The maximum content of combustible gas in the air that explodes when it meets an open flame is called the upper explosion limit -% UEL for short. English: UpperExplorationLimited.
So what is the lower explosive limit? There is no danger if the content of combustible gas is too low or too high. It can only burn or explode when it mixes with air to produce a mixture or, more precisely, when it meets oxygen to produce a certain proportion of mixture.
Combustion is a fierce oxidation reaction accompanied by luminescence and heat, which needs three elements: a. combustible (gas); B. Combustion aids (oxygen); C. Ignition source (temperature).
The combustion of combustible gas can be divided into two types. One is diffusion combustion, that is, volatile or leaked combustible gas from the equipment will be mixed with the ignition source.
The other type of combustion is the mixture of combustible gas and air. This type of combustion reaction is intense and fast, and usually produces huge pressure and noise, which is also called explosion. There is no strict distinction between combustion and explosion.
Taizhou Hanyao Electronic Technology Co., Ltd. specializes in the production of various gas detectors: composite gas detector, portable gas detector, toxic gas detector, methane gas detector, combustible gas alarm, VOC detector, hydrogen sulfide detector, carbon monoxide detector, four-in-one gas detector, ozone detector, etc. For more information, please call.