A: INDICATOR BUTTON
In normal operation a green safety band shows around the button. After a flashback the band does not show and the outer shroud must be lifted to

B: PRESSURE SENSITIVE CUT-OFF VALVE
In the event of a flashback the pressure wave will activate the valve to cut off the gas supply automatically.

C: THERMAL CUT OFF DEVICE
Designed to cut off the gas in the event of extreme temperatures such as a hose fire. The unit is activated at 95ºC.

D: SINTERED METAL FLAME ARRESTING ELEMENT
Extensive surface area designed to arrest a flashback flame quickly. The element surface area is important to ensure long service life and to permit high gas flow in normal operation.

E: NON-RETURN VALVE
Upstream of the flame arresting element, this unit ensures no gas can backfeed and ignite incoming gases.