MANUFACTURE OF MII.K POWDER 285 



supply regulating feed (E) which keeps the milk in the vacuum 

 casing at a constant level, an overflow aperture (J) that regulates 

 the thickness of the film, a vacuum pump, a scraper (S) to 

 remove the film of dried milk from the revolving drum and an 

 evacuated receiver (B) for the dried substance. 



The milk is drawn into the drum casing or vacuum chamber 

 by the force of the vacuum in this chamber. By. the proper 

 adjustment of the feed valve and the overflow valve, the milk 

 rises to a given level and stays at that level while operation is 

 in progress. The revolving steam-heated drum slightly 

 dips into the milk in the vacuum chamber and picks up a film 

 of milk which dries under reduced pressure while the drum 

 makes one revolution. The dried film is removed by the auto- 

 matic scraper and the finished dried milk is discharged into the 

 receiver, while the moisture-laden air and vapors escape through 

 a condenser located outside of the drying apparatus. 



The Ekenberg Process. This is also a film drier operating 

 in vacuo. This process was invented by Martin Ekenberg of 

 Stockholm, Sw r eden, in the year 1899 and is covered by a number 

 of United States patents, some of the earlier of which are patent 

 No. 764,995, 1904, and No. 785,600, March 21, 1905. The patents 

 covering this process are owned by the Ekenberg Company of 

 Cortland, N. Y., who are operating numerous milk drying fac- 

 tories in the States of New York and Michigan. 



The Ekenberg milk drier is called exsiccator. It 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 as it is scraped from the 

 drum. This is separated from the large vacuum chamber by a 

 series of air locks, so that the material may be removed without 

 breaking the vacuum in the large chamber. 



The milk, as it enters the vacuum chamber, is sprayed into 

 the concave ends of the drum. In this manner it is fore-con- 

 densed. It is then withdrawn from the vacuum chamber by a 

 pump, and returned again, this time being sprayed upon the 



