Valve having a removable seat

Claim 1

A VALVE COMPRISING A CASING HAVING A PASSAGEWAY THEREIN AND AN INTERNAL ANNULAR SHOULDER ENCIRCLING SAID PASSAGEWAY. A REMOVABLE SEAT MEANS IN SAID CASING HAVING AN ANNULAR SURFACE ABUTTING AGAINST THE INTERNAL SHOULDER OF SAID CASING; SAID CASING HAVING A SUBSTANTIALLY TRANSVERSE BORE EXTENDING BETWEEN SAID PASSAGEWAY AND THE OUTSIDE OF SAID CASING, A PLUG SLIDABLY RECEIVED IN SAID BORE WITH THE INNER END THEREOF ABUTTING AGAINST SAID SEAT MEANS FOR PRESSING SAID SEAT MEANS AGAINST THE SHOULDER IN SAID CASING, SAID BORE HAVING AN INTERNALLY THREADED PORTION EXTENDING BEYOND THE OUTER END OF SAID PLUG, A SEPARATE EXTERNALLY THREADED PLUG-ADJUSTING ELEMENT SCREWED INTO THE THREADED PORTION OF SAID BORE AND ABUTTING AGAINST THE OUTER END OF SAID PLUG TO PRESS SAID PLUG AGAINST SAID SEAT MEANS TO RETAIN THE SEAT MEANS FIRMLY ENGAGED WITH SAID SHOULDER, AND CLOSURE MEANS OUTWARDLY OF AND SEPARATE FROM SAID PLUG-ADJUSTING ELEMENT FOR CLOSING SAID BORE, SAID CLOSURE MEANS INCLUDING ACTUATING MEANS HAVING AN INNER END AXIALLY SLIDABLY ENGAGING SAID THREADED PLUG-ADJUSTING ELEMENT FOR ROTATING THE LATTER TO EFFECT AXIAL ADJUSTMENT OF THE POSITION OF SAID PLUG-ADJUSTING ELEMENT IN SAID BORE FOR LOCKING SAID PLUG IN POSITION TO RETAIN THE SEAT MEANS AGAINST SAID SHOULDER, SAID CLOSURE MEANS INCLUDING SEAL MEANS PLACED WITHIN SAID BORE AND BEING INDEPENDENT OF SAID PLUGADJUSTING ELEMENT AND OF SAID PLUG AND UNAFFECTED BY THE LOCKING ACTION OF SAID PLUG-ADJUSTING ELEMENT ON SAID PLUG.