Abstract: A pressure vent for an explosion proof container. The vent allows a high flow rate of gases to pass from the container while arresting flames and cooling exiting hot gases therein. This precludes the build-up of high peak pressures inside the container. Structurally the vent has a protective cover mounted to the container by a knife hinge on one side and closed by imbedded magnets on the opposite side. In addition, the vent has multilayered material mounted in the same container opening near the interior of the container. A layer of porous stainless steel foam with multiple layers of stainless steel screen is used for this vital multilayered material. The optimum embodiment is obtained by preselecting a relationship between the free space volume inside the enclosed container, the number of layers in the prefilter section of the vent, and the cross sectional area of the vent.

Abstract: A vent device for relieving pressure buildup inside an electrical enclosure due to an internal explosion of gases. A mass of stainless steel foam covers an opening in the enclosure and stops any flames or particles from escaping but provides a large equivalent cross section opening to permit the gases to escape and vent the pressure buildup. An outer cover protects the foam mass from impact damage and shields it from high pressure water spray used in cleaning. The cover is vertically hung from a knife-edge and held closed by means of a permanent magnet. A predetermined pressure differential is sufficient to overcome the attractive force of the magnet and allow the protective cover to be pushed open.