Continuous Process EVAPORATORS 171 
THE CONTINUOUS CONCENTRATOR. 
The inflow of the fluid milk and the outhow of the con- 
densed milk are continuous. The milk is condensed under atmos- 
pheric pressure at 212 degrees F. A rapidly revolving agitator 
throws the milk in a thin film against the steam-heated and con- 
tintiously polished periphery of a jacketed copper drum. By 
keeping the heating surface clean and bright, and the milk 
rapidly moving, the power of the milk to absorb and utilize heat 
is greatly auemented and the rapidity of evaporation increased. 
Description of Continuous Concentrator.—The continuous 
concentrator consists of a hollow copper drum. The copper shel! 
is surrounded by a steam jacket which is insulated. The space 
Fig. 75. The continuous concentrator with preheater and cooler 
Courtesy of Creamery Package Mfg. Co. 
between inner shell and jacket is about one inch. 
This drum carries in its interior, a revolving dasher with 
four-or more blades, according to the size of the machine. and 
similar to an ice cream freezer or a flash pasteurizer. The edge 
of these blades comes in direct contact with the inner surface 
of the shell which is the heating surface, so that when revolving, 
each blade constantly removes from the heating surface any 
milk that adheres to it. 
The blades are pressed against the heating surface by the 
centrifugal force that is generated when the machine is in mo- 
.tion. The arms to which the blades are attached are equipped 
with stops that control their pressure against the heating sur- 
face so as to insure continuous and uniform pressure. ‘The shaft 
which carries the dasher passes through the front and rear heads 
