GB961739A - Double sloping-hearth furnace - Google Patents

Abstract

961,739. Roasting furnaces. K. BECKENBACH. April 11, 1962 [May 12, 1961], No. 13965/62. Heading F4B. A furnace for burning or sintering particulate material such as limestone comprises a vertical charging shaft 10 leading into an upper combustion space 12 having a sloping hearth 14 and a lower combustion space 26 having a further sloping hearth 30 which extends in the reverse direction to the hearth 14 and terminates in a vertical cooling shaft 40. In operation the material enters the furnace by the charging shaft 10 and slides down the two sloping surfaces in succession being heated thereon and is cooled in the cooling shaft 40 before discharge at the bottom of the furnace (not shown). Horizontal combustion chambers 20, 36 are arranged in the upper portions of the vertical walls 16, 34 of the upper and lower combustion chambers opposite to the respective sloping hearths so that combustion gases emerge from the chambers into hollow spaces above the material bed and impinge on the upper portions of the bed. These portions of the bed are also subject to radiation from the combustion chambers. Passages 44 are provided at the upper corners of recesses 42 in the cooling shaft and allow cooling air to be drawn into a fan 50 and supplied through dampercontrolled conduits 58, 60 as primary air to the burners 22, 38 of the respective combustion chambers. Some of the cooling air passes as secondary air into the lower combustion space, combustion gases from which pass up into the upper combustion space and are drawn off finally at the upper end of the charging shaft 10. Alternatively, the fan 50 may be run so as to draw some of the combustion gases downwardly into the cooling shaft.