288 MANUFACTURE OF MILK POWDER 



small quantity of the milk to be desiccated. The cylinders are 

 charged with hot water through pipes (16). Scrapers (21) re- 

 move the dried milk from the cylinders, and a rotating valve 

 arrangement (28 and 29) is provided to catch the dried milk as 

 it is scraped from the cylinders and to carry it from the vacuum 

 chamber without breaking the vacuum. 



In the operation of this machine it is aimed to maintain a 

 partial vacuum, sufficient to cause the milk to boil at a ten> 

 perature of about 157 degrees F. Through the revolving metal 

 cylinders passes a continuous flow of hot water at a temperature 

 somewhat higher than 157 degrees F. but below 212 degrees F., 

 so that the milk is never exposed to 212 degrees F. nor over. 



In the small receptacle of milk at (13) to which the milk 

 is continually supplied from the outside, and as rapidly as it 

 evaporates, the milk is heated, to about 157 degrees F. by the 

 revolving cylinders. It is partly condensed and a thin film of 

 this condensed milk coats the surface of the cylinders where it 

 dries, the dried film is removed from the cylinders by the scrapers 

 and discharged to the outside of the apparatus through the vanes 

 of the four- winged valves (28), located near the bottom on both 

 sides of the vacuum chamber. 



The Buflovak Process. The principle of drying milk and 

 other liquids on a steam- or hot water-heated revolving drum 

 has been put to extensive application through the activities of 

 the Buffalo Foundry Machine Co., Buffalo, N. Y. This com- 

 pany has, during the last decade, invented, constructed and 

 perfected the "Buflovak" vacuum drum drier. Patents were 

 granted their engineer, Mr. O. S. Sleeper, by the United States 

 Government in 1911, 1913, 1914, 1915 and 1916. All these patents 

 were assigned to the Buffalo Foundry & Machine Co. 



These patents pertain to the drum drier as used for whole 

 milk, skim milk, buttermilk and milk products in general. They 

 are applicable to other products as well as to milk, but for milk 

 they are made specially accessible for cleaning and for sanitary 

 control. 



The Buflovak drier consists of a casing in which revolves 

 a steam-heated, polished drum. The milk is fed to the surface 

 or periphery of this drum by a pan located beneath the drum 

 and placed lightly against the drum. The pan has an overflow 



