Fluid actuated pump

Claim 1

A PUMP FOR PUMPING FLUIDS FROM A WELL BORE WHICH COMPRISES: A FIRST TUBULAR MEMBER SUSPENDED WITHIN SAID WELL, AND A POWER FLUID CYLINDER PROVIDED AT THE LOWER END OF SAID TUBULAR MEMBER; A SECOND TUBULAR MEMBER SUSPENDED WITHIN SAID WELL; A STRING OF SUCKER RODS WITHIN SAID FIRST TUBULAR MEMBER; A PLUNGER WITHIN SAID POWER FLUID CYLINDER AND CONNECTED TO SAID STRING OF SUCKER RODS; CONDUIT MEANS IN SAID PLUNGER EXTENDING AXIALLY THERETHROUGH, SAID CONDUIT MEANS HAVING A VALVE THERIN PERMITTING UNIDIRECTIONAL FLOW FROM BENEATH TO ABOVE SAID PLUNGER WHEN THE FLUID BENEATH SAID PLUNGER REACHES A GIVEN PRESSURE; A PUMP CHAMBER ADAPTED TO BE CONNECTED TO THE LOWER END OF SAID POWER FLUID CYLINDER; A FLEXIBLE DIAPHRAGM MEMBER IN SAID PUMP CHAMBER, SAID DIAPHRAGM DIVIDING SAID CHAMBER INTO A FIRST VARIABLE VOLUME COMPARTMENT AND A SECOND VARIABLE VOLUME COMPARTMENT; A VALVE INLET IN COMMUNICATION WITH SAID FIRST COMPARTMENT; A VALVE OUTLET IN COMMUNICATION WITH SAID FIRST COMPARTMENT FOR DISCHARGING FLUID THEREFROM, SAID VALVE OUTLET BEING FLUIDLY CONNECTED TO SAID SECOND TUBULAR MEMBER; SECOND CONDUIT MEANS ESTABLISHING FLUID COMMUNICATION BETWEEN SAID SECOND VARIABLE VOLUME COMPARTMENT AND SAID POWER FLUID CYLINDER BELOW SAID PLUNGER.