US Patent 7926539 Flood vent access door assembly

A flood vent access door assembly having a frame assembly defining a fluid entrance aperture; a door pivotally mounted in said frame assembly, where in the door includes at least one ventilation opening formed through the door; and at least one latching/release mechanism for releasably maintaining the door in a fixed position relative to the frame assembly if a level of fluid is not above a determined level and releasing the door to pivot relative to the frame assembly if the level of fluid is above the determined level, wherein the at least one latching/release mechanism comprises a float means coupled to an elongate release arm for determining the level of fluid and releasing a latch of the at least one latching/release mechanism.