EVAPORATION 



353 



U.S. patent 1016160, 1912. The apparatus depends on the principle of 

 the climbing film, and is illustrated in Fig. 203. It is a vertical tube exter- 

 nally heated apparatus, and consists of a vertical tubular cluster with tubes 

 about 24 feet long. The juice enters the apparatus at the bottom through 

 the pipe a, the heating steam entering at b. Under the influence of ebullition 

 the juice climbs up the interior of the tubes and passes on to the next effect 



in series by way of e. The condensed water 

 is removed at /, and the steam generated 

 after passing through a centrifugal separator 

 leaves at d. 



Stillman Evaporator. This apparatus, 

 contained in U.S. patent 484831, 1892, is 

 shown in Fig. 204. The method of juice 



FIG. 203 



FIG. 204 



circulation is the same as that in Chapman's patents (1752 and 2511 of 

 1888), the central circulating tube, a, being used to establish circulation 

 from cell to cell. Regulation of flow is obtained by a float and weighted 

 lever combination, b, and in order to obtain a film effect the tops of the tubes 

 project over the upper tube plate. 



Witcowitz Evaporator. This type of evaporator, which has become 

 established in central Europe, is illustrated in Fig. 205. The peculiar form 

 of heating surface also finds application in the rapid heating of juices and 

 syrups contained in tanks. 



2B 



