GB302651A - Improvements in apparatus for heating billets and the like - Google Patents

Abstract

302,651. Dreffein, H. A. Dec. 19, 1927, [Convention date]. Metal-heating furnaces; emission of hot gases, preventing.-In a furnace for heating billets in which combustion of gas and air is effected out of direct contact with the billets, the products of combustion are diverted towards the billets by a wall opposed to the flame, and a, part of the products is then returned for recirculation with the flame. In the furnace shown, in which the billets A are fed along a track 23 from a charging opening 17<a> to a discharging incline 23<a>, the roof is stepped to form a spacious combustion chamber 45 where the main heating of the billets is effected and a more restricted channel 53 through which the products of combustion pass on their way to the stack flue 61, and in which the billets receive a preliminary heating. Gas is supplied through a flue 35 and preheated air through damper-controlled pipes 37, the mixture passing into the chamber 45 through ports 31 lined with refractory material and distributed over the width of the furnace. The flame is deflected downwards by the wall 16 and part of the gases is returned to the burner end of the combustion chamber by air jets 55. The billet tracks 23 are carried by spaced walls 20, and circulation of the heating gases beneath the billets is facilitated by the provision of recesses 66 and 21<a> in the side walls and end block 21 respectively, and of transverse passages 67, 65 in the walls 20. Air is supplied to the spaces beneath the billets, and for preventing emission of gases at the charging end of the furnace, through nozzles 24 and 58 respectively. The mixture supplied through the ports 31 contains gas in excess, and combustion is completed by the air supplied through the nozzles. 24, 55, 58.