Oxygen mask exhalation check valve

Claim 1

A COMPOSITE INHALATION-EXHALATION VALVE DEVICE COMPRISING A VALVE BODY HAVING A PASSAGE THERETHROUGH AND A SUPPLY CONNECTION THEREON, A TUBULAR ASSEMBLY WITHIN SAID PASSAGE MOVABLE AXIALLY RELATIVE TO THE PASSAGE, SAID BODY COMPRISING A SPACER HAVING AN EXHALATION PORT THEREIN, A MASK END ELEMENT AND A HOSE SUPPLY AND ELEMENT RELEASABLY JOINED TO RESPECTIVE ENDS OF SAID SPACER, SAID MASK END ELEMENT HAVING AN ANNULAR EXHAUST VALVE SEAT THEREON FORMING AN EXHAUST PORT, AN ANNULAR EXHAUST VALVE ELEMENT ON SAID TUBULAR ASSEMBLY MOVABLE TO SEATED AND UNSEATED POSITIONS RELATIVE TO SAID EXHAUST VALVE SEAT, AN ANNULAR FLEXIBLE CONNECTION BETWEEN SAID TUBULAR ASSEMBLY AND SAID SUPPLY END ELEMENT, RESILIENT MEANS ACTING BETWEEN SAID BODY AND SAID TUBULAR ASSEMBLY NORMALLY URGING SAID EXHAUST VALVE ELEMENT TO SEATED POSITION, AN INHALTION CHECK VALVE PASSAGE THROUGH SAID TUBULAR ASSEMBLY COMMUNICATING BETWEEN THE SUPPLY END ELEMENT AND THE MASK END ELEMENT, AN INHALATION CHECK VALVE SEAT SURROUNDING THE MASK END OF SAID PASSAGE, AN INHALATION CHECK VALVE ELEMENT OPERABLY MOUNTED ON SAID INHALATION CHECK VALVE SEAT, AN ANNULAR OUTWARDLY FACING EXHALATION VALVE SEAT IN SAID SPACER ENCOMPASSING SAID EXHAUST PORT AND LOCATED DOWNSTREAM RELATIVE TO SAID EXHAUST PORT, AN ANNULAR FLEXIBLE CURTAIN VALVE ELEMENT SURROUNDING SAID EXHALATION VALVE SEAT, SAID CURTAIN VALVE ELEMENT HAVING ONE ANNULAR END SECURED TO SAID SPACER ON A SIDE THEREOF OPPOSITE SAID EXHALATION VALVE SEAT, SAID CURTAIN VALVE ELEMENT HAVING AN AXIAL WIDTH SPANNING THE DISTANCE BETWEEN SAID ONE END AND SAID EXHALATION VALVE SEAT, ANOTHER FREE END OF SAID CURTAIN VALVE ELEMENT BEING NORMALLY IN RELEASABLE ENGAGEMENT WITH SAID EXHALATION VALVE SEAT WHEREBY TO INHIBIT FLOW OF AMBIENT AIR INWARDLY THROUGH SAID EXHAUST PORT WHEN SAID EXHAUST VALVE ELEMENT IS INADVERTENTLY OPENED; SAID ANNULAR CURTAIN VALVE ELEMENT BEING RADIALLY EXPANSIBLE TO PERMIT THE EXHAUSTING OF BREATHED AIR THERETHROUGH, AND A SKIRT ATTACHED TO SAID SPACER IN A POSITION SPACED RADIALLY OUTWARDLY FROM SAID CURTAIN VALVE ELEMENT, SAID SKIRT FORMING AN OPENING EXTERIOR TO AND DOWNSTREAM OF SAID EXHALATION PORT, WHEREBY TO OVERLIE SAID CURTAIN VALVE IN PROTECTING RELATIONSHIP.