A Summary of Research into the Basic Principles of Flameproof Enclosure

Abstract

The flameproof enclosure of electrical machines relies on the ability of small gaps between flanges to prevent the transmission of an explosion from inside an enclosure to a flammable atmosphere outside. Obstructions to the free flow of gas from the gaps may sometimes seriously reduce the size of the critical gap for ignition. The mechanism of ignition is explained as being dependent on heat transfer within the flange gap, and on mixing and combustion within the jet of combustion products emerging from the gap. From the theory the sizes of safe flange gaps can be predicted and the effect of obstacles can be explained