Tut Spray Process 303 
milk reaches the spray nozzle under pressure through pipe G. 
The nozzle rotates by means of a traveler ] supported by a track 
1and a roller arrangement i!. The traveler extends down through 
the desiccating chamber, with driving attachment K and [. near 
bottom. The traveler is provided with a brush made of a mass 
of chain links M, depending from the traveler and resting in 
contact with the inner surface of the inclined wall A. This brush 
insures the removal of the dried material from the surface in 
finely divided form. 
If it is desired to control the temperature of the supporting 
surface A during the drying operation, the supporting wall may 
be jacketed, thereby forming a surrounding chamber N through 
which a circulating medium of the desired temperature may be 
passed to effect the proper control of the temperature of the 
surface. 
The design and arrangement of the apparatus covered by 
the above patent is such that while the major portion of the 
surface is constantly exposed to the drying effect of the cyclonic 
current of the heated air, the brush and the traveler which 
propels it, advance around the chamber so as to remove the 
dried milk from each portion of the surface in succession and the 
spray nozzle operates in such a manner as to direct the spray 
of milk against the surface in the rear of the traveler and brush, 
or on that portion of the surface from which the dried milk has 
been removed.? 
CHAPTER XXVI. 
COMMERCIAL MANUFACTURE OF MILK POWDER BY 
THE SPRAY PROCESS. 
Pre-heating of Milk.—It has been demontrated that in order 
to preserve maximum solubility of the finshed product, the fluid 
milk should not be heated above 150 degrees F. 
Accordingly the practice has been generally adopted in 
plants drying milk by spray-drying to heat the milk to from 
140 to 150 degrees F. For this purpose similar equipment is 
used as in the manufacture of condensed milk. 
Pre-condensing of Milk—\WVhile, in the early days of the 
use of the spray-drying principle for desiccating milk, the fluid 
1 See also Dick process, page 335. 
