Nozzles of the lance heads for blowing oxygen from above in the refining processes

Claim 1

In the combination of a steel making furnace including a vessel for containing a bath including molten iron and slag and a lance for conveying oxygen to the bath, the lance including a nozzle for causing the oxygen to eject from the lance as a jet, the nozzle having for the conveyance of the oxygen a passage defined by walls surrounding the passage and having a first zone defined by convergence of the walls in the direction in which the oxygen is to travel through the nozzle, a second zone joined with the first zone and defined by formation by the walls of a throat in the nozzle, the throat including the smallest cross sectional area of the nozzle passage, and a third zone joined with the second zone and defined by divergence of the walls in the direction in which the oxygen is to travel through the nozzle, the improvement in which in the third zone the walls are concave, at the juncture of the second zone with the third zone the walls are convex, the concave portion of the walls curvilinearly merges with the convex portion of the walls so that no angle is formed, the downstream end of the throat is defined by the boundary between the convex portion of the walls and the concave portion of the walls and the downstream end of the throat is spaced from the downstream extreme of the smallest cross section of the throat a distance equal to one-tenth the diameter of the smallest cross section.