Drill string valve

Claim 1

A VALVE ASSEMBLY FOR INSERTION BETWEEN A BORE HOLE DRILLING BIT AND A DRILL-STRING TO ENABLE PLUGGING FLUID TO PASS UNDER THE ACTION OF A PUMP FROM THE DRILL-STRING TO THE BORE HOLE AND TO ALLOW LIQUID TO PASS FROM THE BORE HOLE TO THE DRILL STRING WITHOUT PASSING THROUGH THE BIT, COMPRISING: (A) A TUBULAR CASING COMPOSED OF UPPER AND LOWER PARTS CONNECTED FOR TRANSMISSION OF TORQUE, BUT WITH FREEDOM TO MOVE TELECOPICALLY TO A LIMITED EXTENT, SAID PARTS HAVING AT LEAST ONE PORT FOR PASSAGE OF THE PLUGGING FLUID, AND, AXIALLY SPACED THEREFROM IN THE UPSTREAM DIRECTION, AT LEAST ONE PORT FOR FLOW OF LIQUID FROM THE OUTSIDE TO FILL THE DRILL STRING: (B) FIRST MEANS OPERATIVELY CONNECTED WITH SAID CASING PARTS FOR CLOSING SAID PLUGGING FLUID PORT WHEN SAID CASING PARTS ARE TELECOPICALLY CONTRACTED, AND MEANS TO STOP FLOW THROUGH THE PLUGGING FLUID PORT WHENEVER THERE IS NO PUMPING PRESSURE WITHIN THE CASING, TO PERMIT FLOW THROUGH SAID LAST MEANS BEING RESPONSIVE TO THE PRESSURE OF FLUID PUMPED INTO SAID CASING FROM ABOVE THE PUGGING FLUID PORT FROM WITHIN THE CASING WHENEVER SIMULTANEOUSLY THE CASING PARTS ARE TELESCOPICALLY EXTENDED AND THERE IS PUMPING PRESSURE WITHIN THE CASING; (C) SECOND VALVE MEANS CARRIED BY THE CASING IN FLOW RELATIONSHIP WITH THE STRING-FILLING PORT TO STOP FLOW OUT THROUGH THE STRING-FILLING PORT DURING MUD PUMPING; (D) MEANS CARRIED BY THE CASING IN FLOW RELATIONSHIP WITH THE STRING-FILLING PORT TO SEPARATE ROCK DEBRIS FROM LIQUID FLOWING INTO THE STRING-FILLING PORT; (E) A THIRD VALVE MEANS IN FLOW RELATIONSHIP WITH THE BORE OF THE CASING DOWNSTREAM OF THE PLUGGING FLUID PORT AND OPERATIVELY ASSOCIATED WITH THE TWO CASING PARTS OF CLOSE THE BORE OF THE CASING DOWNSTREAM OF THE PLUGGING FLUID PORT ON TELESCOPIC EXTENSION OF THE CASING.