gas detector with valve: different sizes of electromagnetic valves are available, and will shut-off automatically when it alarm
Siren Gas Detector

(a)  This detector complies with UL Standard 1484.

      (UL 1484: Standard for residential gas detectors) And meets ROHS Standard.

(b)  This detector complies with EUROPEAN Standard EN50054.

      (EN50054: Electrical Apparatus for The Detection Measurement of Combustible

      Gases General Requirements and Test Methods)

(c)  This gas detector plugs into an electrical power outlet of AC 220V~240V 50~60Hz

      (Model: GAS-220) or AC 110V~120V 50~60Hz (Model: GAS-110)

·Power: AC110-240V/50Hz,60Hz
·Mounting: Accessories supplied for wall mounting.
·Alarm volume : ≥85db@1M
·Alarm pattern: BI 0.5s--pause 0.5s repeat this pattern
·Operating Temperature : -10℃ ~ 50℃
·Ambient Humidity : 10%~ 90% RH
·Power Consumption : ≤4 W
·Detection gas type:LPG,NG(LNG),other flammable gas
·Alarm sensitivity : ＜10%LEL

This gas detector(same as gas leak alarm) is designed to detect flammable gas, natural gas (methane)and LP-gas (propane)from ANY source of combustion. It is NOT designed to detect smoke, fire or any other gas.

Whenever the gas detector(same as combustible gas detector) detects flammable gas up to 25% of lower explosive limits, the red light and audio gas alarm sound will automatically turn on in 5 seconds.
When audio alarm sounds, in this event you must at once follow the regular gas alarm procedure.
If the gas level reaches 10% of lower explosive limits, the red light and audio gas alarm sound will automatically turn on in 20 seconds.

If the gas level reduces to 5% of lower explosive limits, the red light and audio alarm sound will automatically turn off in 5 seconds.

Exhaust fan function:

When gas reaches alarm level, the alarm system circuitry will turn on the exhaust fan (Relay). When gas reduces to safety level, the alarm circuitry will turn off the exhaust fan (Relay) and warning sound in 5 seconds.

Please read more detials at our other website.