Hydrostatic pressure operated apparatus

Claim 1

IN APPARATUS ADAPTED TO BE DISPOSED IN A WELL BORE: UPPER AND LOWER CYLINDERS SECURED TOGETHER; LOWER PISTON MEANS IN SAID LOWER CYLINDER AND HAVING A PORTION EXTENDING OUTWARDLY THEREFROM; UPPER PISTON MEANS IN SAID UPPER CYLINDER AND HAVING A PORTION EXTENDING OUTWARDLY THEREFROM INTO SAID LOWER CYLINDER IN ENGAGEMENT WITH SAID LOWER PISTON MEANS; MEANS PREVENTING ENTRY OF WELL BORE FLUID EXTERNALLY OF SAID CYLINDERS INTO SAID CYLINDERS BELOW SAID UPPER AND LOWER PISTON MEANS; SAID UPPER AND LOWER CYLINDERS CONTAINING A GASEOUS MEDIUM BELOW SAID UPPER PISTON MEANS AND LOWER PISTON MEANS, RESPECTIVELY, WHEN DISPOSED IN A WELL BORE CONTAINING A SURROUNDING LIQUID; MEANS FOR CONDUCTING WELL BORE FLUID UNDER PRESSURE FROM THE EXTERIOR OF SAID UPPER CYLINDER INTO SAID UPPER CYLINDER FOR DIRECT ACTION UPON THE UPPER SIDE OF SAID UPPER PISTON MEANS TO SHIFT SAID UPPER PISTON MEANS RELATIVELY DOWNWARD IN SAID UPPER CYLINDER; MEANS FOR CONDUCTING SUCH FLUID UNDER PRESSURE FROM SAID UPPER CYLINDER INTO SAID LOWER CYLINDER FOR ACTION UPON THE UPPER SIDE OF SAID LOWER PISTON MEANS TO SHIFT SAID LOWER PISTON MEANS RELATIVELY DOWNWARDLY IN SAID LOWER CYLINDER; VALVE MEANS ABOVE AND SEPARATE FROM SAID UPPER PISTON MEANS INITIALLY CLOSING SAID WILL BORE FLUID CONDUCTING MEANS TO PREVENT WELL BORE FLUID FROM BEING EXERTED UPON ANY AND ALL PORTIONS OF SAID UPPER PISTON MEANS; AND MEANS FOR SHIFTING SAID VALVE MEANS IN A DIRECTION AWAY FROM SAID UPPER PISTON MEANS TO OPEN POSITION.