Abstract: A refractory immersion tube has an inner passage through which passes molten metal from a metallurgical vessel into a mold and includes an inlet opening for receiving the molten metal and at least one outlet opening extending from the passage for discharging the molten metal into the mold. A refractory annular member is positioned within the passage to restrict the cross-sectional area thereof, thereby to prevent the flow of the molten metal from the outlet opening from being turbulent and for ensuring that such flow is laminar.

Abstract: A vessel, such as a ladle or converter has a wall having extending therethrough a bore. A tube is fixed in a gas tight manner within the bore. The tube has therethrough a cylindrical passage. At least one gas permeable insert is fitted in a gas tight manner within the passage. The insert may be a pre-shaped insert or may be a mass tamped and packed into the passage. The insert may be replaced by drilling the insert from the passage of the tube and fitting a new insert within the passage. A gas connection is connected to the outer end of the tube to supply gas into the tube and through the insert into the interior of the vessel.