US Patent 11466442 Air admittance valve

The present invention relates to an air admittance valve (AAV) that operates automatically at low pressures to selectively open and close an air passageway between an inlet and an outlet. The AAV comprises a valve body having a centrally disposed, internal valve chamber in communication with the ambient environment, and having a valve seat. The AAV includes a sealing member having a flexible diaphragm that is fastened to a support ring, the ring defining one or more lugs on an outer periphery thereof. The AAV further includes a cap member within which the sealing member may be disposed, such that the one or more lugs may interact with an interior surface of the cap. The sealing member may selectively seal or unseal from the valve seat in response to pressure differentials between the inlet and the outlet.