CANE SUGAR. 



In Chapter XVI., methods of steam economy, based on the use of the 

 ' fore evaporator ' and on the use of ' extra steam ' are described ; the steam 

 of low temperature obtained in these schemes is in beet factories used as a 

 source of heat in the pans ; in such a case large heating surfaces become 

 essential and it is important that the heating surface be as efficient as possible, 

 a result to be obtained by the use of calandrias or of short length coils. 



Special Devices in Pans. Chiefly in the beet sugar industry 

 many specialized types of pans have been designed ; of particular interest are 

 those designed for a slow methodical concentration of the low products to 

 grain ; these designs are exemplified in the Freitag, Grosse, and Reboux arrange- 

 ments. The essential idea in these pans is a stirring device whereby the mass 



Fm. 194. 



is kept in slow methodical movement ; in the Freitag pan, the heating surface is 

 a vertical tube calandria and in the Grosse pan, Fig. 193, a system of coils. 

 The Reboux pan, Fig. 194, is peculiar in its arrangement and consists of a 

 horizontal cylinder ; the heating surface is made up of four separate systems 

 of tubes. In all these pans the stirring device makes about four revolutions 

 per minute. 



With the object of obtaining a brisk movement of the thick viscid mass 

 in a pan, arrangements have been devised whereby lire steam or air is injected 

 into the lower part of the pan ; the injection of air was patented by Dr. Winter, 

 of Java, to the end that on nearing the completion of a strike the partial 



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