Vertical shaft furnace

In a vertical shaft furnace for melting metal materials of the type having a vertically elongated melting chamber through which metal descends during use of the furnace, including means defining an inlet opening at the upper portion of said melting chamber for charging metal into said melting chamber;

• means defining an outlet opening at the lower portion of said melting chamber for discharging molten metal therefrom;
• and a plurality of heat-producing means disposed in at least two vertically-spaced rows about the circumference of said melting chamber between said inlet and outlet openings for producing sufficient heat energy to effect melting of metal charged into the furnace inlet opening to form a continuously descending metal column terminating in a pool of molten metal at the lowermost portion of said melting chamber for discharge from the furnace outlet opening,
• the improvement comprising at least three circumferentially spaced-apart heat-producing means in each row, and the lowermost row of heat-producing means being vertically spaced from the lower-most portion of said melting chamber a distance approximately equal to the inner diameter of said melting chamber.