Patent ID: 8342179

Claim:
A face mask assembly for a patient, comprising: a face piece sized to fit over the patient's nose and mouth, and forming a mask chamber between said face piece and the patient's nose and mouth; an inhalation adapter coupled to a first opening in said face piece to deliver a fluid to said mask chamber; at least one filter housing coupled to a second opening of said face piece, said filter housing including a flange portion, an inlet opening communicating with said face piece and defining a passageway connecting said mask chamber to said flange portion; a filter member coupled to said filter housing; a retainer button adjacent said face piece and coupled to said filter housing, said retainer button spaced inwardly from said filter member; and a valve disc coupled to said retainer button adapted to allow gases from said mask chamber to pass through said passageway of said filter housing to said filter member and escape from said passageway to the atmosphere, wherein said valve disc has a dimension less than a dimension of said inlet opening to partially close said inlet opening, and wherein said valve disc opens to allow gases to escape from said face mask and closes to partially close said inlet opening and allow air to enter said face mask.