MANUEACTURE OF MiILK POWDER 299 
being discharged into the cyclonic current at the center, carries 
its Maximum moisture content at that point, gradually surrenders 
it to the air, as it moves outward to the periphery of the cyclonic 
current. The completion of the drying is accomplished in the 
zones of incoming heated air which carry the least humidity. 
Therefore, as the outwardly moving particles of milk surrender 
more and more of their moisture, they pass through dryer zones 
of heated air. This obviously both accelerates the «speed of 
drying and enhances the completeness of the removal of moisture. 
+. Inasmuch as the danger of the sclubilitv-destroving effect 
of heat is greatest while the milk is still in the liquid state, and 
this effect is practically completely absent in milk from which 
the bulk of moisture has been removed, this process has the ad- 
ditional advantage of maximum preservation of the solubility 
in the finished product. The temperature of the cyclonic air 
current, is lowest when it reaches the center where the moisture 
content of the milk is greatest. Dy the time the particles of milk 
come in contact with the hottest air (at the periphery) their 
moisture content is lowest. 
5. This process tends to facilitate maximum recovery of 
the milk powder. The moisture-laden air escapes in the center. 
where the particles of milk are heaviest, and where their greater 
specific gravity causes them to partake of the centrifugal motion 
moving them outward until when completely dried. they strike 
the steeply tapered confining walls of the drying chamber and 
fall to the bottom of this chamber. 
Gray patent No. 1,157,935 involves, in addition to the new 
and advantageous features established under patent No. 1,107,784, 
and explained above. apparatus and a method for supporting the 
milk or other substance to be desiccated on and by the introduc- 
tion of a solid, sheet-like, or finely divided substance. In the 
case of milk, the supporting or absorbing material used may be 
previously desiccated milk. 
The desiccating chamber A described in this patent 1s similar 
to the desiccating chamber shown under patent No. 1,107,784. 
and the intake of the heated air B and discharge of the moisture- 
laden air C are unchanged. The intake of the milk and support- 
ing material into the desiccating chamber is located in the center 
