Apparatus for degassing metals

Claim 1

IN A VACUUM DEGASSING VESSEL OF THE TYPE HAVING A NOZZLE EXTENDING FROM ITS LOWER END AND MEANS FOR PRODUCING RELATIVE MOVEMENT OF SAID VESSEL AND A LADLE OF MOLTEN METAL DISPOSED THEREBELOW SO THAT A CHANGE IN THE RELATIVE DISTANCE BETWEEN SAID VESSEL AND LADLE WILL DRAW MOLTEN METAL THROUGH SAID NOZZLE AND INTO SAID CHAMBER FOR DEGASIFICATION, THE IMPROVEMENT COMPRISING A REFRACTORY LINING FOR SAID VESSEL, THE LOWER END OF SAID LINING FORMING A BASE PORTION AND BEING DEFINED BY A PLURALITY OF REFRACTORIES DISPOSED IN SIDE BY SIDE ABUTMENT AND SUBSTANTIALLY DEFINING A SPHERICAL SECTOR, THE RADIUS OF CURVATURE OF SAID SPHERICAL SECTOR BEING SUBSTANTIALLY LARGER THAN THE HEIGHT OF SAID VESSEL SO THAT THE MELT WITHIN SAID VESSEL WILL FORM A SHALLOW POOL HAVING A LARGE SURFACE AREA, SAID NOZZLE HAVING A CENTRAL BORE WHOSE UPPER END OPENS INTO THE LOWER END OF SAID LINING, A PLURALITY OF REFRACTORY SHAPES IN SAID BASE PORTION AND SURROUNDING THE UPPER END OF SAID BORE, EACH OF SAID REFRACTORY SHAPES HAVING A CURVED SURFACE TERMINATING IN SAID BORE AND THE SPHERICAL UPPER SURFACE OF SAID BASE TO PROVIDE A SMOOTH