288 Manvuracturlé of Mink PowprrR 
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 tem- 
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 
eranted 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 
