High-Quality Gas Alarms Systems Factory & Factories

The Lower Explosive Limit (LEL) is the minimum volumetric concentration of a combustible gas in air capable of propagating a flame in the presence of an ignition source. For Methane (CH4), 100% LEL corresponds to roughly 5.0% gas concentration by volume in atmospheric air (50,000 ppm).

Detection alarm setpoints are never set at 100% LEL. Regulatory safety frameworks (such as EN 60079-29-1 and NFPA 72) require dual-stage thresholds: typically Low Alarm (AL1) set at 10%–25% LEL to initiate local ventilation, and High Alarm (AL2) set at 50% LEL to trigger emergency shut-off valves and isolate power supplies before an explosive air-fuel mixture forms.

Our interlocking architecture couples detectors directly with the JYFJS-011 electromagnetic shut-off valve. In an alarm condition, the detector or central controller discharges a DC power pulse (typically 9V–24V) to the valve's coil within milliseconds. This trips a spring-loaded mechanical latch, snapping the valve disc shut instantly.

Critically, the JYFJS-011 is engineered with a strict manual reset mechanism. The valve cannot re-open via electrical signal or controller command. Maintenance personnel must physically visit the location, verify the leak has been repaired, vent residual pockets, and pull the mechanical lever manually, ensuring total operational safety.

Stand-Alone Point Detectors (e.g., SD2130 Series) integrate sensor, sounder, and output relay directly inside a unified housing. They function autonomously without requiring an external control panel, making them ideal for single-room installations like commercial bakeries, boiler rooms, and residential dwellings where localized shut-off is needed.

Distributed Bus-Type Detectors (e.g., SD2100A/E Series) operate via non-polarized 2-wire M-Bus or 4-wire RS-485 Modbus networks, routing telemetry to a multi-channel central controller (e.g., SD8001A/B) in a non-hazardous control room. This centralizes diagnostic logging, cross-zone interlocking, remote span calibration, and automated fire/BMS system handshakes across expansive chemical plants.

Clean atmospheric air naturally contains roughly 20.9% Oxygen (O2) by volume. A decrease below 19.5% VOL triggers rapid cognitive impairment and suffocation risks, while concentrations exceeding 23.5% VOL create extreme hyperoxic fire hazards. Because the measurement envelope is so large, volume percent (%VOL) provides clean, readable data.

Conversely, toxic threats such as Carbon Monoxide (CO) and Hydrogen Sulfide (H2S) are lethal at micro-concentrations. For instance, an H2S concentration of merely 100 ppm (0.01% by volume) paralyzes the olfactory nerve and causes rapid fatality. Parts Per Million (PPM) provides the ultra-fine resolution needed to protect personnel in confined spaces.

With an active line of over 80 marketable safety products, we support Tier-1 white-label and full ODM development programs. Customization spans injection tooling for private-label industrial enclosures, bespoke PCB trace design, tailored LCD/OLED user interfaces, proprietary communication firmware, customized calibration ranges, and market-specific packaging.