End-of-line Flame Arresters
End-of-line (EOL) flame arresters are fitted to the end of a pipeline or exit to a vessel to prevent atmospheric deflagrations (flames) from entering, and not, as is often believed, to prevent the flame exiting the vessel or pipeline. Weatherhoods are supplied to protect the flame arrester element and prevent the ingress of water and foreign debris. They are usually fitted in a vertical orientation.
In-line Flame Arresters
In-line flame arresters are generally fitted in piping systems to protect connected equipment. The layout shown above is typical although it is also possible that the source of ignition could cause the flame to travel with the gas flow. If the flame could occur from either direction then a bi-directional flame arrester is required. In-line flame arresters can be either deflagration or detonation arresters depending on the conditions under which they are to be used. Pipe orientation is not usually a problem unless liquid is entrained in the gas flow and possibly collecting in the bottom of the arrester. In such situations, an eccentric flame arrester housing may be fitted to facilitate collection and drainage of the liquid.