Device for the continuous addition of casting auxiliaries onto the surface of a melt in a continuous-casting mold

A device for the continuous addition of casting auxiliary in powder form onto a bath surface of a melt, the device comprising:

• a continuous-casting mold containing the melt, the continuous-casting mold having a top surface;
• a tundish having a bottom surface;
• a screw conveyer disposed between the top surface of the continuous-casting mold and the bottom surface of the tundish;
• a supply tank having the casting auxiliary therein, the supply tank being connected to the screw conveyer to allow the casting auxiliary to pass from the supply tank into the screw conveyer;
• a plurality of removal shafts in communication with an interior of the screw conveyer, each of the plurality of removal shafts having a lower end which is located a predetermined distance above the bath surface;
• and
• a return line connecting an end of the screw conveyer to the supply tank;
• wherein said screw conveyer receives the casting auxiliary from the supply tank and conveys the casting auxiliary through the interior of the screw conveyer such that at each of the plurality of removal shafts a portion of the casting auxiliary passes therethrough and exits from the lower end of each of the plurality of removal shafts onto the bath surface, and the casting auxiliary which does not pass through the plurality of removal shafts is returned to the supply tank via the return line;
• wherein the predetermined distance ensures that the portion of casting auxiliary removed at each of the plurality of removal shafts is self-regulated by a chicken feeding principle, and a capacity of the screw conveyer to convey the casting auxiliary is at least twice as large as a capacity of all of the plurality of removal shafts to remove the casting auxiliary from the screw conveyer.