OUTSIDE CHANGE TUYERE

1,170,559. Tuyeres. UNION CARBIDE CORP. 16 July, 1968 [17 July, 1967], No. 33736/68. Heading F4B. A removable tuyere assembly 1 insertable from the outside in a vessel for the gaseous treatment of molten metals comprises a nozzle 5 and tuyere tube 11 covered by a refractory head 3, sleeves 14 and 15 and an asbestos expansion washer 13 held by a nut 12, a nozzle adapter 9 acting as a heat sink to solidify back flowing molten metal when the gas flow is reduced or shut off. As an additional preventative of metal run back a steel or copper screen may be coiled in the nozzle 5. The latter is attached to tube 11 by an adapter 10 and the nozzle adapter 9 engages a recess 7 in the head 3 plugged by a high alumina refractory 8 and dry fireclay 29 surrounding a nozzle tip 6. The assembly is disposed with a mortar bond in a socket formed in the vessel wall by a hole in the refractory and steel sleeves welded to the shell and clamped therein by a locking plate with notches passing through stops welded to the sleeves, said plate being then twisted to lock the assembly (Figs. 1 and 3). To remove the tuyere in case the mortar does not break, a weak point is created in part of the tube assembly to form a point of fracture