Blowout preventer for wells

Claim 1

A SUBSURFACE BLOWOUT PREVENTER FOR CONCENTRIC PIPES ADAPTED TO CLSE OFF THE ANNULS BETWEEN SAID PIPES AND TO CLOSE OFF SAID INNER PIPE COMPRISING A FIRST MANDREL CONNECTED IN SAID INNER PIPE AND FIRST PRESSURE CHAMBER FORMED THEREON, A FIRST PISTON ARM BEING SAID PRESSURE CHAMBER HAVING A FIRST AND SECOND POSITION AND PROVIDED WITH A PISTON ARMM BEING PROVIDED WITH A FIRST RACK, FIRST BIASING MEANS ARRANGED IN SAID FIRST PRESSURE CHAMBER ADAPTED TO URGE SAID FIRST PISTON TO SAID FIRST POSITION, A FIRST VALVE MEMBER PIVOTALLY SECURED TO SAID FIRST MANDREL AND HAVING TEETH THEREON ENGAGING WITH SAID FIRST RACK, SAID FIRST VALVE MEMBER BEING ADAPTED TO CLOSE OFF SAID FIRST MANDREL FROM FLUID FLOW THERETHROUGH WHEN SAID FIRST PISTON IS IN SAID FIRST POSITION, A FIRST CONDUIT CONNECTED TO SAID FIRST MANDRAL FLUIDLY COMMUNICATING SAID FIRST PRESSURE, SAID CHAMBER WUTH A SOURCE OF FLUID PRESSURE,SAID FLUID PRESSURE BEING ADAPTED TO MOVE SAID FIRST PISTON AGAINST THE BIAS OF SAID FIRST BIASING MEANS, A SECOND MANDREL CONNECTED IN SAID OUTER PIPE AND HAVING SECOND AND THIRD PRESSURE CHAMBERS FORMED THEREON, SECOND AND THIRD PISTON SLIDABLY ARRANGED IN SAID SECOND AND THIRD PRESSURE CHAMBER, RESPECTIVELY SAID SECOND AND THIRD PISTONS HAVING FIRST AND SECOND POSITION AND BEING PROVIDED WITH SECOND AND THIRD PISTON ARMS, RESPECTIVELY, SAID SECOND AND THIRD PISTON ARMS HAVING SECOND AND THIRD RACKS PROVIDED THEREON, RESPECTIVELY, SECOND AND THIRD BISASING MEANS ARRANGED IN SAID SECOND AND THIRD PRESSURE CHAMBER, RESPECTIVELY, ADAPTED TO URGE SAID SECOND AND THIRD PISTONS TO SAID FIRST POSITTIONS, SECOND AND THIRD VAVLE MEMBERS PIROTALLY SECURED TO SAID SECOND MANDREL, SAID SECOND AND THIRD VALVE MEMBERS HAVING TEETH THEREON ENGAGEING WITH SAID SECOND AND THIRD RACKS, RESPECTIVELY, SAID VALVE MEMBERS BEING AND THE THIRD PISTON ARE IN SAID FIRST POSITIONS, A SECOND OUTER PIPES FROM FLUID FLOW THERETHOUGH WHEN SAID SECOND AND THIRD PISTONS ARE IN SAID FIRST POSITIONS, A SECOND CONDUIT CONNECTED TO SAID SECOND MANDREL FLUIDLY COMMUNICATING SAID SECOND AND THIRD PRESSOURE CHAMBERS WITH A SOURCE OF FLUID PRESSURE, SAID FLUID PRESSURE BEING ADAPTED TO MOVE SAID SECOND AND THIRD PISTON AGAINST THE BIAS OF SAID SECOND AND THIRD BIASING MEANSM RESPECTIVELY.