System for automatically injecting a measured quantity of powdered reagent into a pool of molten metal

A system for automatically controlling the injection of powdered reagent from a dispenser vessel into a pool of molten metal through a conduit interconnected with said dispenser vessel and with a generally vertically disposed movable tubular lance, said system comprising lance manipulating means for imparting movement to said lance, a convey gas reservoir interconnected with said conduit valve means in said conduit and operable in coordination with movement of the lance toward said pool of molten metal and actuated by convey gas control means which is engageable by a part movable with said lance to initiate the flow of convey gas through said conduit and lance, common control means for controlling the flow of powdered reagent into said conduit and for controlling movement of the lance and actuated in coordination with continued movement of the lance toward the pool of molten metal and effective to arrest such movement of the lance and to initiate the flow of powdered reagent from said dispenser vessel through the lance and into the molten metal when the lance reaches a predetermined level, and measuring control means responsive to reduction in weight of said dispenser vessel and of powdered reagent therein for sensing the injection of a predetermined quantity of powdered reagent into said molten metal for activating said common control means and thereby to cut off the flow of powdered reagent through the lance and to activate said lance manipulating means so as to lift the lance out of the molten metal.