Passenger mask assembly

Claim 1

A BREATHING MASK ASSEMBLY FOR PASSING SEQUENTIALLY BREATHING GASES TO A SUBJECT COMPRISING A FLEXIBLE WALLED FACE RECEPTACLE, MEANS FORMING A GAS PASSAGE THROUGH THE SAID RECEPTACLE, A MULTIPLE VALVE MEMBER HAVING A PASSAGEWAY THERETHROUGH ADAPTED TO COMMUNICATE WITH SAID GAS PASSAGE AND AN ANNULAR OUTWARDLY FACING EXHAUST VALVE SEAT SURROUNDING SAID PASSAGEWAY, A VALVE BODY ON SAID RECEPTACLE AND SPACED MEANS SEPARATING SAID BODY FROM THE RECEPTACLE AT A LOCATION SURROUNDING SAID PASSAGEWAY AND FORMING EXHAUST PASSAGE MEANS THEREBETWEEN, SAID MULTIPLE VALVE MEMBER HAVING AN ANNULAR VALVE ELEMENT RECIPROCABLY MOUNTED THEREIN AT A LOCATION ADAPTED TO ENGAGE SAID EXHAUST VALVE SEAT AND HAVING A MIXED GAS SUPPLY PASSAGE THERETHROUGH, AN INFLOW CHECK VALVE FOR SAID MIXED GAS SUPPLY PASSAGE, A CHAMBER IN SAID BODY,