Pouring of metals

Claim 1

In a slidable gate member for controlling flow of liquid metal through an outlet in the bottom wall of a vessel, said member comprising: metal encased superposed upper and lower refractory rings having an orifice; the refractory of said upper ring being abrasion resistant for sliding contact with a plate thereabove; the refractory of said lower ring being of low conductivity; a nozzle depending from said plate and having a passage extending from said orifice; the improvement in which said nozzle comprises: an annular member of low-conductivity permeable refractory material extending from said lower ring; a metal casing enclosing the outer circumference of said annular member; a sleeve of highly erosion resistant permeable refractory inside said annular member and having a bore which defines said passage; an inlet connected with said annular member and extending through said casing for introducing gas to said sleeve and through the permeable refractory thereof to said bore throughout the length of said sleeve to form a separating film between the metal being poured and the inside surface of said sleeve; and means forming a seal at the lower surface of said annular member to prevent escape of gas.