THE SPRAY PROCESS 303 



milk reaches the spray nozzle under pressure through pipe G. 

 The nozzle rotates by means of a traveler I supported by a track 

 i and a roller arrangement i 1 . The traveler extends down through- 

 the desiccating chamber, with driving attachment K and L 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. 1 



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 finished 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. While, in the early days of the 

 use of the spray-drying principle for desiccating milk, the fluid 



1 See also Dick process, page 335. 



