How Combustible Gas Detector Works

Combustible gas is a kind of gas with diffusion property. To prevent accidents caused by flammable gas leakage, the key is to effectively control its continuous diffusion. In addition, combustible gases will spread rapidly under the action of external forces. As a result, burning and explosion accidents can occur. How to prevent such accidents? What we need to do is to constantly check whether the concentration of combustible gas exceeds the standard. Once the concentration exceeds the limit, call the police and we will take immediate action. Therefore, combustible gas detector plays an important role in ensuring life and production.

Combustible Gas Detector
How does a combustible gas detector work?

A combustible gas detector is a kind of gas leak detector that monitor the concentration of single or multiple combustible gases and give an alarm. LEL gas detectors are mainly divided into two types, catalytic type and infrared optical type base on the working principle.

The catalytic combustible gas detectors measure the concentration of combustible gas according to the resistance change of refractory metal platinum wire after heating. When the combustible gas enters the detector, it will cause oxidation reaction on the surface of the platinum wire (flameless combustion), and the heat generated will cause the rise in the temperature of the platinum wire. Then, the resistivity of the platinum wire will change, and the detected data will also change and sound an alarm.

Combustible Gas Detectors

The infrared optical type combustible gas detector makes use of an infrared sensor to monitor the combustible gas in the field environment based on the absorption principle of the infrared light source. When the gas passes through the infrared beam, the beam will be distorted, and the gas detector will figure out what kind of gas it is according to the distortion of light.

Both infrared sensor and catalytic sensors are commonly used in combustible gas detectors, and each gas sensor has its advantages and disadvantages. The infrared sensor is more durable and have a longer service life because it doesn’t have direct contact with the gas. In addition, it has less requirement for calibration because the gas detector can constantly re-adjust the beam. The catalytic sensor is less susceptible to dust and dirt, therefore it can monitor most hydrocarbons and hydrogen. And it is also not affected by humidity, condensation, pressure or temperature. Therefore, we need to fully understand their pros and cons and select the most appropriate combustible gas detector according to the practical applications.

Gas Detector
Combustible gas detector application

A construction company often needs to undertake underground job and requires a multi-gas detector for monitoring the LEL, CO, H2S and O2. As the underground environment is not ventilated for a long time, some harmful gases may be produced by fermentation. Therefore, ventilation must be carried out before the personnel go down for the construction. After ventilation, it is required to detect whether the underground environment is suitable for personnel to go down. If the environment is not up to standard, it must be ventilated until it meet the standard.

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