1 84 



Condensed Milk and Milk Powder 



2. The Just-Hatmaker Process. — The milk sprays in a thin 

 film over two steam heated cylinders or drums, about sixty inches 

 long and twenty-four inches in diameter. The cylinders are about 

 one-eighth of one inch apart and revolve in opposite directions. The 

 milk reaches the drums from a supply tank located in the center 

 above the drums. In order to insure a continuous and uniform sup- 

 ply of milk, a constant level of about four inches of milk is main- 

 tained in the supply tank. This process was invented by J. R. Hat- 

 maker of London, and was patented in 1902. Its objectionable fea- 



Fig. 55. The Just-Hatmaker milk drier 



ture lies in the fact that the excessive heat at whith the milk is 

 evaporated impairs the solubility of the product. The cylinders are 

 charged with two to three atmospheres of steam pressure, causing 

 the heating surface to have a temperature of about 250 to 280 de- 

 grees F. 



3. The Eckenburg and Passburg Processes.— In the Ecken- 

 burg process the milk is exposed in a thin layer on the surface of a 

 revolving metal cylinder or drum, which is enclosed in a vacuum 

 chamber. The cylinder is heated by passing hot water or steam 

 through it. The fact that the evaporation takes place in a vacuum 

 chamber makes it possible to accomplish the drying at a relatively 



