Abstract: A nozzle of refractory material is demountably connected to a spout, also of refractory material, for flow of liquid metal from the spout into the nozzle. The spout is supported by a first metal support ring and the nozzle is carried by a second metal support ring which has projecting arms by which it is lifted to bring the nozzle into position. To provide a seal of the connection against access of atmospheric oxygen to the liquid metal, a sleeve is slidably and rotatably mounted on the second support ring. On rotation of the sleeve, cam means a cam action between the lower sleeve surface and the projecting arms effect its upward movement so that its top edge engages the first support ring to seal thereto. The sleeve leaves an annular gap between itself and the nozzle, to which inert gas is supplied.