Drilling fluid circulation system having flow parameter regulating means

Claim 1

IN A DRILLING FLUID CIRCULATION SYSTEM A FLOW PARAMETER REGULATING APPARATUS COMPRISING; A PLURALITY OF SERIALLY CONNECTED BLADDER VALVES COMMUNICATING WITH MEANS FOR DELIVERING PRESSURIZED DRILLING FLUID FROM A WELL, EACH SAID VALVE INCLUDING A VALVE BODY AND A FLEXIBLE BLADDER MOUNTED THEREIN HAVING A CENTRAL LONGITUDINAL PASSAGE THERETHROUGH FOR ACCOMMODATING THE FLOW OF PRESSURIZED DRILLING FLUID THROUGH SAID VALVE, SAID VALVE BODY AND SAID BLADDER DEFINING THEREBETWEEN A BLADDER ACTUATING CHAMBER FOR RECEIVING COMPRESSED GAS THEREIN TO FLEX SAID BLADDER AND VARY THE SIZE OF SAID CENTRAL PASSAGE; A PRESSURE REGULATOR COMMUNICATING WITH EACH SAID BLADDER ACTUATING CHAMBER FOR REGULATING THE GAS PRESSURE WITHIN THE ACTUATING CHAMBER TO THEREBY CONTROL THE SIZE OF SAID CENTRAL PASSAGE; A SOURCE OF COMPRESSED GAS COMMUNICATING WITH EACH SAID PRESSURE REGULATOR FOR SUPPLYING COMPRESSED GAS TO THE REGULATOR TO BE METERED INTO THE BLADDER ACTUATING CHAMBER COMMUNICATING THEREWITH; AN EXPANSIBLE CHAMBER MEANS CONNECTED TO EACH SAID PRESSURE REGULATOR AND INCLUDING A MOVABLE CONTROL MEMBER MOUNTED THEREIN FOR OPERABLY CONTROLLING THE FLOW OF COMPRESSED GAS METERED THROUGH SAID REGULATOR; AND