Tuk Spray PRocEss 309 
fect of the uncontrollable fluctuations in the humidity of the at- 
mospheric air, as affected by weather conditions. However, in 
commercial operation the artificial drying of the atmospheric air 
is generally omitted. 
The air may be blown into the desiccating chamber by a 
blower fan, in which case a suction fan is frequently also installed 
to draw the moisture-laden air from the desiccating chamber ; or the 
injection of the air into the drying chamber may all be taken care 
of by a strong suction fan located at the air exhaust end of the 
desiccating chamber. It is claimed that the double arrangement 
of blowing in and drawing out of the heated air, requiring less 
powerful suction at the exhaust end, minimizes the escape of milk 
powder with the moisture-laden air and thereby facilitates the 
recovery. ‘The speed of the drying action and the exhaustiveness 
of desiccation may be augmented by introducing the air in such a 
manner as to produce a cyclonic air current moving spirally toward 
the center of the drying chamber, where it escapes while the milk 
spray issues from the center, is acted on by the centrifugal force 
and moves tangentially toward the periphery as shown in the Gray 
patents. 
The temperature of the air as it enters the desiccating cham- 
ber is generally held at from 250° to 300° F., the temperature of 
the motsture-laden air discharging from the drying chamber ranges 
from 150° F. to 200° F. 
Spraying and Desiccating.—The drying is accomplished by 
forcing the milk or condensed milk, in the form of an atomized 
spray, into the current of heated air in such: a manner, that the 
fluid milk particles, or atoms of the milk spray, remain in suspen- 
sion sufficiently long to cause them to surrender substantially all 
of their moisture. The dried particles or flakes of milk are al- 
lowed to deposit at the bottom or sides of the drying chamber or in 
a separate collecting chamber, from where they are removed for 
sifting and packing through a hopper, while the moisture-laden air 
escapes separately to the outside. 
The Desiccating Chamber.—The desiccating chambers in 
commercial use vary considerably in size and in shape, as well as 
in arrangement of spray nozzles and intake and outlet of heated 
air. 
