MANUFACTURE OF MiLK POWDER 283 
The Gathmann Process.—'This process and equipment was 
invented and patented by Louis Gathmann of \Vashington, 
D. C., U.S. patent No. 834,516, October 30, 1906, 
In this process, similar as in the Just process. the milk 1s 
dried in the iorm of a film on a revolving, steam-heated drum 
under atmospheric pressure. In this case, however, only one 
drum is used, the drum (A) is cone-shape instead of cylindrical 
and its surface is spirally grooved or corrugated (a) and the 
adjacent surface against which the cone revolves is also similarly 
corrugated but the spiral grooves (b!) running in the opposite 
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Fig. 94. The Gathmann milk drier 
direction from those on the cone, as is common in grinding- 
mills. Hence when the cone revolves the drying milk is kneaded 
and ground between the two surfaces and is gradually carried 
or pushed by the corrugated surface of the revolving cone to 
the smaller, or discharge end of the machine. 
The adjacent corrugated surface against which the surface 
of the cone grinds, and which incases the lower half of the surface 
of the cone, is steam jacketed (b*), so that the milk is hetween 
two heated surfaces. 
A hopper (D) regulates and feeds the flow of the milk to 
the cone at its larger end and a brush (G) located near the 
smaller end of the cone removes such parts of the dried milk 
