Gasoline tank

Claim 1

AN UNDERGROUND TANK FILL CONSISTING OF A FILL PIPE AND FILL BOX, A GASKETED COUPLING CONNECTED THEREWITH AND A TELESCOPING EXTENSION PIECE HAVING UPPER AND LOWER ENDS AND EXTENDING WITHIN COUPLING, SAID FILL PIPE HAVING AN INSIDE DIAMETER AND AN OUTSIDE DIAMETER AND EXTENDING FROM UNDERGROUND TANK TO WITHIN FILL BOX MOUNTED AT GROUND SURFACE AND SAID FILL PIPE TERMINATING IN A STANDARD EXTERNAL SCREW THREAD; SAID COUPLING CONSISTING OF AN UPPER PORTION AND A LOWER PORTION, THE UPPER PORTION DRILLED WITH A FIRST VERTICAL, LONGITUDINAL BORE EQUAL IN DIAMETER TO INSIDE DIAMETER OF FILL PIPE AND THE UPPER PORTION BEING PROVIDED WITH AN INTERNAL RECESSED, CIRCUMFERENTIAL GROOVE COMMUNICATING WITH SAID FIRST LONGITUDINAL BORE, SAID LOWER PORTION DRILLED WITH A SECOND VERTICAL, LONGITUDINAL BORE SLIGHTLY SMALLER THAN OUTSIDE DIAMETER OF FILL PIPE, BOTH BORES BEING CONCENTRIC AND IMMEDIATELY ADJOINING FORMING A CONTINUOUS CYLINDRICAL OPENING OF TWO DIAMETERS, SAID SECOND LONGITUDINAL BORE TAPPED WITH AN INTERNAL SCREW THREAD COOPERATING WITH AND CONNECTED TO SAID EXTERNAL SCREW THREAD OF FILL PIPE, SAID COUPLING HAVING AN INTERNAL SHOULDER AT JUNCTION OF SAID TWO LONGITUDINAL BORES; A WATER-TIGHT GASKET BETWEEN SAID SHOULDER OF COUPLING AND TOP OF FILL PIPE ARRANGED TO SEAL CONNECTION BETWEEN THREADS OF COUPLING AND THREADS OF FILL PIPE; A WATER-TIGHT RING GASKET SEATED FIRMLY WITHIN SAID RECESSED, CIRCUMFERENTIAL GROOVE, SAID RING GASKET HAVING INTERNAL DIAMETER LESS THAN DIAMETER OF FIRST LONGITUDINAL BORE AND SMALLER THAN OUTSIDE DIAMETER OF EXTENSION PIECE; THE TELESCOPING EXTENSION PIECE CONSTRUCTED OF PIPES OR TUBING OF EXTERNAL DIAMETER OF SUCH SIZE TO PERMIT INSERTION OF LOWER END WITHIN FILL PIPE AND IN SLIDEABLE ENGAGEMENT THEREWITH, SAID EXTENSION PIECE FORMING A WATER-TIGHT SEAL WITH RING GASKET SECURED IN COUPLING AND TERMINATING AT THE UPPER END IN AN EXTERNAL SCREW THREAD, SAID EXTENSION PIECE FITTING ENTIRELY WITHIN FILL PIPE AND FILL BOX IN LOWEST POSITION AND EXTENDING ABOVE FILL PIPE AND FILL BOX IN RAISED POSITION; AND A SCREWED FILL CAP CONNECTED WITH EXTERNAL THREADS AT UPPER END OF EXTENSION PIECE WHEREBY A GROUND WATER EXCLUDING TANK FILL IS PROVIDED.