Patent ID: 7798893

Claim:
Explosion vent apparatus comprising: a vent support unit adapted to be positioned over the outlet of an area to be protected from an overpressure condition, said support unit defining a vent opening aligned with the outlet; a vent panel movably mounted on said unit in a closed position blocking the outlet, said panel being movable from said closed position to open overpressure-relieving positions; and structure on the unit connected to the vent panel normally maintaining the vent panel in the closed position thereof, said structure being operable to allow movement of the vent panel through a first displacement away from said closed position to a first open overpressure-relieving position upon application of an overpressure of one magnitude of pressure against the vent panel, and permitting movement of the panel through a second and greater displacement than said first displacement to a second open overpressure-relieving position upon application of an overpressure of a second magnitude of pressure higher than said one magnitude of pressure against the vent panel, wherein said structure that normally maintains the vent panel in the closed position thereof includes a plurality of spaced, laterally aligned rupturable tab components oriented in disposition such that tension forces are exerted on the tab components when an overpressure is applied to the vent panel, said tab components resisting rupture while allowing the vent panel to move through said first displacement to said first open overpressure-relieving position when an overpressure of said first magnitude of pressure is a lied to the vent panel, said tab components collectively undergoing rupture when an overpressure of said second magnitude of pressure is applied to the vent panel and allowing the vent panel to move through said second displacement thereof to said second open overpressure-relieving position.