Abstract: A smoke stack which receives at the lower end thereof dirty hot waste gases and receives adjacent the upper and thereof a constant flow of raw cold juice, the juice and the gases flowing in contra directions. A dual purpose is achieved since the cold juice flowing downwardly against the upward flow of the hot gases will result in the separation of charcoal and other impurities from the hot gas and the cold juice will be heated to the boiling point without the necessity of using separate fuel to produce steam for this purpose.

Abstract: An evaporator which is specifically adapted for the evaporation of sugar cane juices, however, it is a versatile apparatus and may be used with equal facility in various evaporating situations. Instead of using steam as is conventional, the heating medium to produce the required evaporation comprises waste combustion gases. Gas orienting means is included through which the hot waste gases flow to an enclosed area of generally hour glass shape. The entire apparatus is of generally circular configuration and includes a circular evaporating area into which the juices are pumped and are under pressure and in which they are evaporated. The circular evaporating area into which the juices are pumped and where evaporation occurs is in heat transfer relationship with the enclosed area through which the hot waste gases flow.