| 摘要 |
<p>1,089,988. Shaft furnaces. A. SCHMID and H. HOFER. Nov. 15, 1965 [Nov. 17, 1964], No. 48349/65. Heading F4B. A multiple shaft kiln for burning limestone comprises outer shafts 1 and 2 each with preheating zone V, firing zone B, cooling zone K, feed hopper 3 and fuel pipes 4, and central shaft 7 having an offtake 9, the shaft dividing walls being discontinued as shown over most of the firing zone depth. Outer shafts 1 and 2 are charged with particles in the size range 60-150 mm., and shaft 7 with particles in the size range 10-60 mm., and the outer shafts are fired alternatively. Primary air enters the firing shaft downwardly and hot gases pass from this shaft across the material in the central shaft to exhaust up the other outer shaft. Cooling secondary air is supplied up all the shafts and a controllable part of the hot gases are extracted through offtake 9. When the exhaust gases reach a given temperature the firing process is reversed in the outer shafts.</p> |
