Flashback Arrestor Safety Device

A flashback arrestor integrates multiple safety features to prevent catastrophic equipment failure. The core component is the flame barrier, often a cylinder of sintered bronze or stainless steel. This material has a porous, sponge-like structure with a very high surface area. If a flame front enters the arrestor, it is forced through these tiny, tortuous passages. The large surface area of the metal rapidly absorbs heat from the flame, cooling the gases below their autoignition temperature and extinguishing the flame, a principle known as flame quenching.

In addition to the flame barrier, a spring-loaded non-return valve (or check valve) is included. This allows gas to flow in the correct direction but snaps shut if a back-pressure event occurs, preventing the reverse flow of gas. This is vital to stop oxygen from mixing with fuel gas inside the fuel hose, or vice-versa, which would create a highly explosive mixture. More advanced arrestors also incorporate a thermal cut-off valve. This valve is held open by a low-melting-point solder. If a sustained backfire heats the arrestor to a dangerous temperature, the solder melts, and a spring-loaded valve closes, completely shutting off the gas supply.