Gas Detector

A gas detector is an instrument tool for monitoring the content of gas leaks, including portable gas detectors, handheld gas detectors, fixed gas detectors, and online gas detectors. It primarily uses gas sensors to monitor the types of gases present in the environment, with gas sensors being used to detect the composition and content of gases.

Gas sensors are typically categorized based on their monitoring targets. In other words, any sensor used to monitor gas composition and content is considered a gas sensor, whether it employs physical or chemical methods. For instance, sensors that monitor gas flow are not classified as gas sensors, but thermal conductivity gas analyzers are, even though they sometimes use similar monitoring principles.

Burning

These sensors are created with a heat-resistant catalyst layer on the surface of platinum resistors. At certain temperatures, combustible gases are catalytically combusted on the surface. The combustion raises the temperature of the platinum resistor, causing a change in resistance, which is a function of the combustible gas content.

Semiconductor

It is produced based on the principle that the electrical conductivity of some metal oxide semiconductor materials varies with the composition of the ambient gases at certain temperatures. For example, alcohol sensors are made using the principle that the resistance of tin dioxide sharply decreases when it encounters alcohol vapor at high temperatures.

LEL

"LEL" refers to the Lower Explosive Limit—the minimum concentration of a flammable gas in air that can ignite upon contact with an open flame. Abbreviated as %LEL, it is known as the Lower Explosive Limit in English.

The maximum concentration of a flammable gas in the air that can cause an explosion when ignited is referred to as the Upper Explosion Limit (UEL).

What is the lower explosive limit? The content of flammable gases is not dangerous when it is too low or too high; it can only mix with air to form a mixture or, more precisely, a mixture with a certain proportion of oxygen upon contact with it, which will then ignite or explode.

Combustion is a fierce oxidation reaction accompanied by light and heat, requiring three elements: a, fuel (gas); b, oxidizer (oxygen); and c, ignition source (temperature).

Combustion of combustible gases can be categorized into two types: diffusion combustion, where volatile or leaked gases from equipment come into contact with an ignition source and mix for combustion.

Another type of combustion involves the ignition of a mixture of combustible gas and air, which is a highly reactive and rapid process, often resulting in immense pressure and noise, known as an explosion. There is no strict distinction between combustion and explosion.

Taizhou HanYao Electronics Technology Co., Ltd. specializes in manufacturing various gas detectors, including composite gas detectors, portable gas detectors, toxic gas detectors, CH4 gas detectors, flammable gas alarms, VOC detectors, H2S detectors, CO detectors, four-in-one gas detectors, and ozone detectors. For more details, please feel free to call for consultation.