354 The Commercial Apple Industry 



belts or conveyers. Essentially, the drier consists of sev- 

 eral superimposed metal cloth conveyers or canvas belts 

 in a long tunnel. The material to be dried enters the 

 tunnel on the upper belt, traverses the length of the tunnel, 

 drops to the second belt, and so on until it may travel back 

 and forth five to seven times at such a speed that it emerges 

 from 1 the lower belt dry. If such a machine could be built 

 successfully for fruits, it would, doubtless greatly reduce 

 labor costs. It has possibilities and will bear further 

 study and development. 



Distillation types of evaporators. 



In these evaporators the water is distilled from the fruit 

 and the vapors are condensed. 



Atmospheric pressure machines. — In this type the drier 

 is not placed under a vacuum but is, however, rather 

 tightly closed to the outside air. In one form the fruit 

 travels on belts over steam coils. The heat from the coils 

 drives the moisture from the fruit. The vapor passes 

 over water-cooled pipes and is condensed, giving an area of 

 reduced pressure toward which the vapors continually 

 flow. In another type the air and gases of combustion 

 from a furnace heat the fruit and carry the moisture to 

 condensers. This evaporator is really a combination of 

 the distillation and air blast forms. 



Vacuum driers. — Insofar as quality of dried product is 

 concerned, the vacuum drier is in a class by itself. No 

 other drier compares with it in its ability to produce dried 

 fruits of fresh flavor, color and aroma. There are two 

 reasons for this, one being the practical absence of air in 

 the vacuum drier, a fact which accounts for lack of oxida- 

 tion, and a second reason for its superiority is the low 



