Improvements relating to smelting furnace assemblies and the method of operating them

摘要

The flue gases from a melting furnace, heated by the combustion of fuel in technically pure oxygen, are passed to a tank or tanks to preheat the raw material for the next charge, contained therein. The fuel together with an insufficient quantity of a 95% oxygen composition for complete combustion is fed via burner 2 to tiltable furnace 1, the exhaust gases produced passing through a Y' branched, refractory lined open ended flue 3 into tapered tubular tanks 4, having an inlet to outlet area ratio of between 5 to 1 and 2 to 1 to preheat the raw material for the next charge. Additional preheated oxygen-enriched air is provided before the tanks 4 to complete combustion of the fuel. On completion of the melting of the charge, burner 2 and flue 3, now covered by end covers 11 to prevent cooling, are withdrawn, the furnace 1 tapped and the preheated burden skip charged from the tanks 4 by crane lifts 12, 13 to the furnace. Burner 2 and flue 3 are then replaced and a new tank 4 containing a fresh charge to be preheated inserted between flue 3 and abutment 17 leading to the exhaust system through bellows 18 which take up any expansion. During the tapping and charging the Y flue 3 may be repaired by spraying. In a second embodiment Fig.4 (not shown) a furnace fitted with a swivelable cover plate which may be removed as well as the burner and flue, or a cover plate secured to the flue to be removed with it to facilitate charging is disclosed. In this latter case the furnace may be mounted on wheels. A pressure gauge is mounted in the flue 3, the signal from which is used to control the induced draught to within /sB3 mins w.g. of a desired value.