Furnaces, esp. Cowper stoves, with improved thermal efficiency - where heat in waste gases is reclaimed via heat exchanger using cyclic evapn. and condensn. of heat transfer fluid

摘要

Air and fuel gas are preheated in a heat exchanger before entering a furnace, which is esp. one or more Cowper stoves. The fumes or exhaust gases leaving the stove are kept at a higher temp. than is generally used, and are fed into the exchanger to provide the heat required. Exchanger consists of a tube with a capillary lining contg. a heat transfer medium which evaporates at the hot end of the tube and condenses at the other end. This known type of static heat exchanger provides a heat transfer of several kW/sq.cm., i.e. it is very efficient. The exhaust gases leaving the Cowper stove are pref. at 400-500, esp. 400-425 deg.C. The invention provides an efficient method of heat recovery, which may also be used in pit, pusher-, forging-, or glass melting- furnaces.