The working principle of the LNG leak alarm device is mainly based on the detection of natural gas leaks by gas sensors. The following is a detailed description of its working principle:
1. Gas sensor detection
The core of the LNG leak alarm device is the gas sensor, which can detect the concentration of natural gas (mainly methane) in the air. Common sensor types include:
Catalytic combustion sensor: The concentration of combustible gas is determined by the change in resistance after heating the refractory metal platinum wire, which is suitable for combustible gases such as hydrogen and carbon monoxide.
Electrochemical sensor: The gas concentration is detected by the resistance change caused by the oxidation-reduction reaction of the gas on the surface of the semiconductor.
Infrared absorption sensor: The gas concentration is measured by the selective absorption characteristics of different gases for infrared rays, which is suitable for hydrocarbon combustible gases such as methane and ethane.
2. Signal conversion and transmission
When the gas sensor detects that the natural gas concentration exceeds the set threshold, it will convert the detected signal into an electrical signal and transmit it to the control circuit through the sampling circuit. The control circuit identifies and processes the electrical signal.
3. Alarm and linkage
Sound and light alarm: If the control circuit identifies that the natural gas concentration exceeds the standard, the alarm device will send out sound and light alarm signals to remind the operator or surrounding personnel to take emergency measures.
Linkage function: Some advanced alarm devices also have the function of automatically closing the gas valve and starting the exhaust to ensure that the danger is effectively controlled.
4. Installation and maintenance
Installation location: The alarm should be installed in the parts where leakage may occur, such as valves, flanges, joints, etc., and avoid interference with other equipment and ventilation systems.
Regular maintenance: It is necessary to regularly check the power supply and detector sensitivity of the alarm, and test the alarm function to ensure its normal operation.
Through the above mechanism, the LNG leak alarm device can detect natural gas leaks in time and take corresponding measures, thereby effectively ensuring the safety during transportation.