70 



CONDENSED MILK CONDENSING 



of pan makes possible such an arrangement of the heating sur- 

 face as to take care of the maximum amount of milk with the 

 minimum depth of milk over the heating surface and that this 

 arrangement is most desirable. They hold that because the wide 

 and shallow pan offers a larger area of evaporating surface, it 

 therefore makes possible more rapid evaporation than the narrow, 

 deep pan. They further emphasize that in the wide, shallow 

 pan, the milk boils more quietly, is under better control and is 

 less apt to be carried over into the condenser and lost, than in 

 the narrow, deep pan. 



The advocates of the 

 narrow, deep pan claim that 

 their type of pan increases 

 the rapidity of evaporation 

 because it causes the milk 

 to pass over the heating sur- 

 face more rapidly. When 

 the pan is in operation, the 

 boiling milk travels from the 

 center of the bottom toward 

 the periphery where it rises, 

 rolls over the coils, and re- 

 turns to the center. It is 

 claimed that a pan with a 

 shallow jacket, such as the 

 rtarrow, deep pans have, 

 causes the milk to roll over 

 higher, especially if the coils 

 are close to the periphery 

 and leave plenty of vacant 

 space in the center of the 

 pan. This, in turn, means 

 more rapid circulation of the 

 milk, causing it to pass over the heating surface at greater speed, 

 and oftener, which naturally enables the milk to utilize more heat 

 and, therefore, to evaporate more quickly. Because in such pans 

 the milk rolls over higher, they require a deeper body. 



Experience has demonstrated .that for maximum rapidity of 

 evaporation, other factors being the same, maximum rapidity of 



Fig. 17. Vacuum pan and condense! 



Courtesy of Mojonnier Bros. Co. 



