Storm choke

Claim 1

AN ASSEMBLY SIZED FOR RECEPTION AND AXIAL TRAVEL IN STATIONARY WELL TUBING FOR CONTROLLING THE FLOW OF FLUID THERETHROUGH, SAID ASSEMBLY COMPRISING A TUBULAR VALVE BODY HAVING A GENERALLY ANNULAR SEAT, A BALL PLUG FREELY CARRIED BY THE BODY FOR BODILY MOVEMENT BETWEEN A DOWN POSITION IN WHICH THE PLUG IS SPACED BELOW THE SEAT AND AN UP POSITION IN WHICH THE PLUG ENGAGES THE SEAT TO BLOCK UPWARD FLOW THERETHROUGH, THE BODY HAVING A BORE RECEIVING THE BALL PLUG IN SAID DOWN POSITION AND OPENING UPWARDLY TO DIRECT THE BALL UPWARD MOVEMENT TOWARD THE SEAT, THE ASSEMBLY HAVING SUPPORT STRUCTURE UNDERLYING THE PLUG IN DOWN POSITION AND FIRST PORTING LOCATED TO BY-PASS THE UPWARD FLOWING WELL FLUID ARROUND THE PLUG IN SAID DOWN POSITION AND ALSO TO COMMUNICATE THE FLOW PRESSURE TO THE UPPER SIDE OF THE PLUG IN SAID BORE, AND SECOND PORTING LOCATED TO COMMUNICATE THE FLOW PRESSURE TO THE LOWER SIDE OF THE PLUG IN SAID BORE, SAID PORTING BEING SIZED TO CREATE A FLOW PRESSURE DIFFERENTIAL ACROSS THE PLUG SUFFICIENT TO EFFECT UPWARD MOVEMENT THEREOF TO SEAT THE BALL PLUG WHEN THE UPWARD FLOW RATE REACHES A VALUE WITHIN A PREDETERMINED RANGE, THE ASSEMBLY INCLUDING HOLDING MEANS RELEASABLY ENGAGEABLE WITH TUBING SHOULDERS TO ALLOW LOWERING OF THE ASSEMBLY IN A TUBING STRING AND TO RESIST RAISING OF THE ASSEMBLY THEREIN, THE VALVE BODY AND PLUG