Fluid pressure operated bottom hole pump

Claim 1

A PUMP INSTALLATION COMPRISING A VERTICALLY ELONGATED PUMP BARREL ADAPTED TO BE SUBMERGED IN A LIQUID IN A WELL, SAID BARREL COMPRISING A HOUSING CLOSED FROM THE ATMOSPHERE AND HAVING A NON-RETURN PUMP INLET VALVE EFFECTING THE INTAKE OF LIQUID INTO SAID BARREL BUT PREVENTING REVERSE FLOW, A PUMP DELIVERY CONDUIT ENTERING SAID PUMP BARREL AND HAVING A DELIVERY CONDUIT INLET COMMUNICATING WITH THE LOWER PORTION OF THE PUMP BARREL, A NON-RETURN PUMP DELIVERY VALVE IN SAID CONDUIT INLET ADMITTING LIQUID FROM SAID PUMP BARREL INTO SAID DELIVERY CONDUIT WHILE PREVENTING REVERSE FLOW, FLUID PRESSURE PUMP OPERATING MEANS INCLUDING AN AUTOMATIC SELECTOR VALVE PERIODICALLY SUPPLYING AN OPERATING GAS UNDER PRESSURE INTO SAID PUMP BARREL AND THEREBY DISCHARGING ACCUMULATED LIQUID THEREIN INTO SAID DELIVERY CONDUIT INLET AND SUBSEQUENTLY PERIODICALLY VENTING THE PUMP BARREL INTERIOR TO THE ATMOSPHERE, PRESSURE RESPONSIVE VALVED PASSAGE MEANS MOUNTED WITHIN THE PUMP BARREL COMMUNICATING THE INTERIOR OF SAID PUMP BARREL WITH THE WELL BORE WHEREBY A RAPID EQUALIZATION OF PUMP BARREL-WELL BORE PRESSURE IS FACILITATED, SAID FLUID PRESSURE PUMP OPERATING MEANS CLOSING SAID PASSAGE MEANS WHEN OPERATING GAS UNDER PRESSURE IS BEING SUPPLIED INTO SAID PUMP BARREL AND OPENING SAID PASSAGE MEANS WHEN SAID PUMP BARREL IS BEING VENTED TO THE ATMOSPHERE.