Pressure responsive control valve for well tubing

Claim 1

A WELL FLOW CONTROL DEVICE INCLUDING: A TUBULAR OUTER MEMBER; A TUBULAR VALVE ELEMENT LONGITUDINALLY MOVABLY MOUNTED IN SAID TUBULAR OUTER MEMBER AND HAVING A VALVE SEAT AT ITS LOWER END; A VALVE CLOSURE MEANS CONNECTED TO SAID TUBULAR MEMBER ALSO MOVABLY MOUNTED IN SAID TUBULAR MEMBER AND ENGAGEABLE WITH THE VALVE SEAT AT THE LOWER END OF SAID TUBULAR VALVE ELEMENT TO CLOSE THE SAME; MEANS IN SAID TUBULAR OUTER MEMBER BIASING SAID TUBULAR VALVE ELEMENT LONGITUDINALLY THEREIN TO A POSITION WHEREIN SAID SEAT IS CLOSINGLY ENGAGED BY SAID VALVE CLOSURE MEANS TO PREVENT FLOW OF FLUIDS THROUGH SAID OUTER TUBULAR MEMBER COMPRISING A FIXED PREDETERMINED CHARGE OF GASEOUS PRESSURE CONFINED WITHIN SAID OUTER MEMBER AND ACTING UPON SAID TUBULAR VALVE ELEMENT TO MOVE SAID VALVE ELEMENT TOWARD SUCH CLOSED POSITION UPON THE OCCURRENCE OF A PREDETERMINED PRESSURE CONDITION WITHIN THE BORE OF SAID TUBULAR MEMBER ABOVE SAID VALVE ELEMENT, SUCH GASEOUS PRESSURE CHARGE CONTROLLING THE PRESSURE CONDITIONS UNDER WHICH THE VALVE ELEMENT WILL BE MOVED TOWARD CLOSED POSITION; AND MEANS ON SAID VALVE ELEMENT RESPONSIVE TO FLUID PRESSURE OF THE FLUIDS FLOWING THROUGH SAID TUBULAR OUTER MEMBER AND WITHIN THE TUBULAR MEMBER DOWNSTREAM OF THE VALVE ELEMENT FOR MOVING THE VALVE ELEMENT LONGITUDINALLY IN SAID TUBULAR MEMBER TO A POSITION OUT OF ENGAGEMENT WITH SAID VALVE CLOSURE MEANS TO PERMIT FLOW OF FLUIDS THROUGH SAID TUBULAR VALVE MEMBER, WHEREBY THE PRESSURE OF THE FLUIDS FLOWING THROUGH SAID VALVE MEMBER ACTS THEREON TO HOLD THE SAME IN OPEN POSITION.