Improvements in or relating to Drying or Heating Apparatus of Continuous Type.

摘要

134,332. Dressler Tunnel Ovens, Ltd., and Williamson, J. Nov. 1, 1918. Tunnel kilns.-A continuous kiln for heating or drying goods in an atmosphere free from combustion products comprises a longitudinal passage containing an air heater, and a second passage above the first and communicating directly with its upper part and through a return passage or passages in the walls with its lower part, and supporting a carrier by which the goods are conveyed continuously through the apparatus, the air circulating continuously between the two passages. Preliminary drying is effected by the passage of moderately heated air through the goods in one part of the apparatus, this air being discharged from the upper part; air entering the apparatus is used to cool the finished goods. The apparatus shown in Fig. 1 comprises a combustion chamber b surrounded by a casing c perforated at the top and bottom; the passage along which the combustion chamber extends opens at its upper part into a longitudinal drying or heating chamber f through which trucks comprising trunnions carrying trays k convey the goods, the trucks passing back to the feeding end of the kiln through a lower passage n connected to the heating chamber by a descending passage in which the goods are discharged and a corresponding ascending passage. The hot air passes through the top of the heating chamber and circulates through flues t, t1 to the heater b. The separate roof s of the chamber f may be dispensed with. The preliminary dryer, Fig. 2, comprises air heating and drying chambers a, f forming continuations of those shown in Fig. 1, the combustion products from the heater b, Fig. 1, passing through the air heating tubes y, and the moist air escaping by the exit z. A cooling section at the exit end receives air from the outside, this air, after passing through the cooling portion, being withdrawn by a fan, and forced partly into the heater b, Fig. 1, to support combustion and partly into contact with this heater and with the goods in the passage f.