MANUFACTURE: OF MII<K POWDER 237 



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 

 supply of milk, a constant level of about four inches of milk is 

 maintained in the supply tank. This process was invented by J. R. 

 Hatmaker of London, and was patented in 1902. Its objectionable 

 feature lies in the fact that the excessive heat at which the milk is 

 evaporated impairs the solubility of the product. The cylinders are 

 charged with two to three atmospheres of steam pressure, causing 



Fig. 59. The Just- Hatmaker milk drier 



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

 degrees F. 



The Ekenberg Process. This process was invented by Martin 

 Ekenberg, of Stockholm, Sweden, in the year 1899, and is covered 

 by a number of United States patents, one of the earlier of which 

 is patent No. 764995, issued in 1904. 



The Ekenberg Exsiccator, or milk drier, consists of a revolving, 

 steam heated nickel drum, inclosed in a vacuum chamber. The ends 

 of the drum form bell-shaped bowls, dished outward. The drum 

 is equipped with knives or scrapers, which remove the film of dried 

 milk that gathers on the drum. Attached to the vacuum chamber 

 there is a smaller chamber which serves to receive the dried milk 



