Porous refractory nozzle and method of making same

摘要

A nozzle for discharging molten metal from a vessel includes a porous inner sleeve surrounded by an impervious outer sleeve. The outer sleeve is cast in-situ around the inner sleeve, and is bonded in-situ to the outer surface of the inner sleeve in bonding areas adjacent its opposite ends. A gas chamber is defined between the inner and outer sleeves for receiving pressurized gas which passes through the inner sleeve to inhibit clogging and deterioration of the inner sleeve by molten metal and impurities. The gas chamber is formed by placing a heat fluidizable material around a portion of the inner sleeve before the outer sleeve is cast thereon. After casting of the outer sleeve, the assembly is heated to a temperature for fluidizing the fluidizable material which then escapes through the porous sleeve to leave a hollow gas chamber.