Demand type oxygen valve

Claim 1

IN A DEMAND TYPE OXYGEN VALVE, THE COMBINATION COMPRISING: A HOUSING HAVING AN INTERIOR SPACE; A FLEXIBLE DIAPHRAGM IN SAID HOUSING FORMING IN COOPERATION WITH THE HOUSING A CHAMBER, THE DIAPHRAGM BEING EXPOSED AT ONE SIDE TO ATMOSPHERIC PRESSURE AND YIELDING TO PRESSURE OF FLUID MEDIA AT OPPOSITE SIDES THEREOF; A HOLLOW, RIGID CORE EXTENDING THROUGH A HOUSING WALL AND THE DIAPHRAGM CENTRALLY THEREOF; MEANS COOPERABLE WITH SAID CORE AND SAID WALL TO ANCHOR THE DIAPHRAGM TO SAID WALL AT THE CORE, SAID CORE HAVING A PORT OPENING BETWEEN THE ENDS THEREOF INTO SAID CHAMBER; MEANS PROVIDING A PASSAGE FROM SAID CHAMBER TO A USER OF THE DEMAND TYPE VALVE; AN ANNULAR VALVE MEMBER SURROUNDING AND MOVABLE RELATIVE TO THE CORE AND MOVABLE TO A POSITION COVERING SAID PORT IN THE CORE TO PREVENT ENTRY OF GAS INTO THE CHAMBER; MEANS BIASING SAID VALVE MEMBER TOWARD SAID POSITION COVERING THE PORT; AND MEANS ENGAGEABLE BY THE DIAPHRAGM AND MOVABLE THEREBY TO MOVE THE VALVE MEANS IN OPPOSITION TO THE BIASING MEANS TO A POSITION UNCOVERING THE PORT IN RESPONSE TO FLUID PRESSURE ON THE DIAPHRAGM.