Patent ID: 8360105

Claim:
An air admittance vent (“AAV”) comprising: a vent body having a cylindrical side wall adapted for fitting to a vent pipe and an integral end wall, the vent body end wall having a central bore therein and a plurality of vent openings radially spaced around the central bore, the bottom of the vent body end wall has a conical surface diverging downward from the central bore and an annular ridge protruding downward around the conical surface, the conical surface and the annular ridge define a valve seat; a valve element supported by the vent body for movement in response to vacuum pressure within a plumbing system between an open position to allow airflow through the vent openings and a closed position for preventing airflow through the vent openings, the valve member includes a post reciprocally seated within the central bore and a pliable diaphragm mounted to the post, the diaphragm is spaced from the valve seat when the valve member is in the open position and abuts the valve seat such that the diaphragm first contacts the annular ridge before the diaphragm contacts the conical surface when the valve element is moved from the open position to the closed position; and a spring operatively connected between the vent body end wall and the valve element responsive to low vacuum conditions in the vent pipe to permit the valve element to move from the closed position to the open position in response thereto, the diaphragm has a flat peripheral edge that stretches around the annular ridge in sealed engagement when the valve element is in the closed position.