For industrial gas-fired burner which using NG (natural gas) and LPG (liquefied petroleum gas), gas leak detection is mandatory. This is not only a legal requirement but also a core measure to prevent fires and explosions and ensure production safety.
A fixed combustible gas leak detector like EX gas detector,Industrial lpg gas leak detector or NG detector is required. The installation height must be determined based on the gas's specific gravity (NG is lighter than air, so the detector should be installed above the leak source; LPG is heavier than air, so the detector should be installed 0.3-0.6 meters above the ground). It should have explosion-proof certification (e.g., Ex d II CT6), output a 4-20mA or RS-485 signal, and be integrated with a PLC/DCS system for centralized monitoring and automatic linkage.
To achieve automatic supply cut-off in case of a gas leak, the core is to integrate the lpg gas detector, alarm controller, and emergency shut-off valve into a linked system. When the lpg detector detects a leak and reaches the alarm threshold, the controller immediately issues a command to close the shut-off valve; the entire process typically takes 1-2 seconds.
Wired relay linkage (the most common and reliable method): The natural gas detector transmits a signal to the controller. When an alarm is triggered, the internal relay of the controller activates, outputting a passive switch signal (normally open/normally closed contact) to the drive module (electromagnet or motor) of the shut-off valve, thus completing the shut-off.
Furthermore, the signals from all lpg detectors and shut-off valves are connected to the factory's PLC or DCS system. Through software programming, complex interlocking logic (such as AND and OR conditions) can be implemented, and the status of all equipment can be remotely monitored and manually shut off from the central control room computer.
Our company's fixed natural gas detectors meet explosion-proof requirements and have obtained CE, ATEX, and Exd IICT6 certifications. They output 4-20mA or RS-485 signals, have an IP65 waterproof and dustproof rating, a detection range of 0-100% LEL, an alarm at 25% LEL, and 24-hour online monitoring. They convert gas concentration into an electrical signal and upload it to the controller for real-time data transmission. When the alarm point is reached, the relay on the control panel immediately controls the solenoid valve to cut off the gas supply. Furthermore, data can be transmitted to the cloud via the Internet of Things (IoT).