SUGAR BOILING AND CRYSTALLIZATION-IN-MOTION 401 



The Greiner short coil pan is shown in Fig. 247. The heating surface 

 consists of a number of concentric elements supported on cast-iron standards. 

 Steam is admitted and condensed water removed at the bottom of each 

 element. The valve A controls the admission of steam to the smaller 

 elements, which are used in forming grain, and that at B to the larger ele- 

 ments used, when the pan is operating at full capacity. 



Pans similar to those described above have usually two sq. ft. heating 

 surface to one of net capacity. 



Tubular Pans. The tubular or calandria pan has its heating surface 

 made up of tubes secured at either end in tube plates. This type of pan, 

 which is claimed as new in Walker's patent (14141, 1852), is indicated in 

 Fig. 248, where a coil in the saucer is also shown. The coil is usually oper- 



n 



FIG 248 



FIG. 249 



ated with live steam, exhaust steam being used in the calandria, the tubes 

 in which are generally not less than four inches in diameter. Other arrange- 

 ments of tubular calandrias are shown diagrammatically in Figs. 245 and 246, 

 the object of these arrangements being to obtain a sloping surface on which 

 the massecuite may not lodge. The inclined calandria is claimed in Frey- 

 tag's patent (8064 of 1888). Pans of this type, which afford two sq. ft. 

 heating surface to one cu. ft. net capacity, were originally introduced into Cuba 

 as a means of using up surplus exhaust steam from a multiplicity of small 

 pumps and engines. At the present day they are again being largely 

 installed in connection with the schemes described in Chapter XVIII for the 

 economic utilization of steam, and for this purpose the short coil pans are 

 equally applicable. 



Pans are also built with horizontal tubes similar in shape and arrangement 

 of heating surface to the Welner-Jelinek evaporator (q.v.), except that the 



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