Patent ID: 7628167

Claim:
Vent apparatus for protecting a confined space having a vent aperture for relief of an overpressure condition, said vent apparatus comprising: vent structure including a vent unit adapted to be positioned over the vent aperture in normal closing relationship thereto said structure being provided with a movable pressure relief portion having an initial closed position across the vent aperture and movable to an open position extending away from the vent aperture when a predetermined overpressure in the confined space is applied against the relief portion of the vent unit through the vent aperture, said relief portion being defined by a line of weakness in the vent unit; and a backstop disposed in a selected position to be engaged by and to arrest movement of the pressure relief portion of the vent unit during opening thereof to an extent that the modulus of elasticity of the movable pressure relief portion is not exceeded, said backstop being operable to absorb and dissipate kinetic energy in the movable pressure relief portion as it engages the backstop, said relief portion of the vent apparatus having a sufficient modulus of resilience and elasticity to cause the relief portion to return from its open position to its initial position upon relief of the overpressure condition.