A flashback arrestor or flame arrestor is a device most commonly used in oxy-fuel welding and cutting to stop the flame from burning back up into the equipment and causing damage or explosions. The two main types are dry and wet. Each has its own advantages and disadvantages. Most oxy-fuel flashback arrestors are the dry type.
Dry flashback arrestors typically use a combination of methods to stop flashback. This is the type that is typically found on most workshops, home or portable oxy-fuel kits as they work just as effectively with any orientation, need very little maintenance, and are often small and light enough to be installed between the torch and hoses. They include:
Flame trap to cool the flame front. They are designed to allow free flow of gas through them but to take the heat out of the flame front to get it below the ignition temperature of the burning gas mixture. The most common types are:
Temperature-triggered valves to stop the gas flow completely. Because it relies on extracting heat from the flashback to stop it continuing, most arrestors have a temperature-controlled valve that will cut off the gas flow when the unit reaches around 90°C, until either the unit cools (if the unit is automatic) or the reset button is pressed (if the unit is manual).