Safety apparatus for oxygen system

Claim 1

IN COMBINATION WITH AN OXYGEN REGULATOR HAVING A WALL ENCLOSING A DEMAND CHAMBER PROVIDED WITH OUTLET MEANS FOR CONDUCTING OXYGEN FROM THE CHAMBER TO A USER AND FURTHER HAVING AN OXYGEN INLET PASSAGE AND A DEMAND VALVE CONNECTING AND GOVERNING THE FLOW OF OXYGEN BETWEEN SAID INLET PASSAGE AND CHAMBER, A SAFETY DEVICE COMPRISING: A PORTION OF SAID WALL HAVING AN ORIFICE PROVIDING COMMUNICATION BETWEEN AMBIENT AIR AND SAID DEMAND CHAMBER; A BELLOWS HAVING A FREE END FACING AND A SECOND END MOUNTED IN FIXED RELATION TO SAID ORIFICE, SAID BELLOWS INCLUDING MEANS BIASING SAID BELLOWS TO A COLLAPSED POSITION, UPON EQUALIZATION OF PRESSURE INTERIORLY AND EXTERIORLY OF SAID BELLOWS, WHEREIN SAID BELLOWS FREE END IS SPACED FROM SAID ORIFICE; AND MEANS PROVIDING RESTRICTED COMMUNICATION BETWEEN THE INTERIOR OF SAID BELLOWS AND SAID OXYGEN INLET PASSAGE, SAID MEANS BEING DISTINCT FROM SAID DEMAND VALVE AND INCLUDING A METERING OPENING BETWEEN SAID BELLOWS AND SAID INLET PASSAGE SUFFICIENTLY SMALL TO RETARD EQUALIZATION THERETHROUGH OF PRESSURE IN THE BELLOWS INTERIOR AND THE INLET PASSAGE BY A PLURALITY OF SECONDS UPON AN ABRUPT LOSS OF OXYGEN PRESSURE IN THE INLET PASSAGE.