292 MANUFACTURE OF MILK POWDER 



the solid constituents of liquids, such as blood, milk and the like, in 

 the form of powder, said process consisting in converting the liquid 

 into a fine spray, bringing such spray or atomized liquid into a reg- 

 ulated current of heated air, so that the liquid constituents are com- 

 pletely vaporized, conveying the dry powder into a suitable collect- 

 ing space away from the air current, and discharging the air and 

 vapor separately from the dry powder." 



The Stauf patent shows a vertical drying chamber (e) into 

 which the liquid (milk) to be desiccated is atomized through jets 

 or nozzles (b) under pressure, into a fine spray. A current of 

 heated air is admitted at the bottom of the drying chamber (f ) run- 

 ning in the same direction as, and mixing with, the spray of milk, 

 and evaporating the watery constituents of the spray. The steam 

 and dried particles are carried upward by the heated air, retaining 

 the atoms momentarily in the current of hot air and causing them 

 to surrender substantially all the remaining moisture in the form of 

 vapor, and the product is prevented by the cooling effect of such 

 evaporation from undergoing chemical change. The vapors and 

 dried atoms are guided by a cone (g) extending downward from the 

 top into the drying chamber, into collecting chambers (h) where the 

 desiccated milk or dry powder gathers in hoppers (i) away from 

 the vaporizing current. The moisture-laden air or gas is separated 

 from the dry powder and escapes through the sides of the collecting 

 chamber, which consist of mill gauze, woolen fabric or like pervious 

 material. 



The McLachlan Process. This process was patented by 

 John C. McLachlan of Chicago, 111., U. S. patent No. 806,747, De- 

 cember 5, 1905. This process is a modification of the Stauf process. 



McLachlan uses a tall vertical drying chamber (B) surrounded 

 on its sides by a jacket or casing (A), containing steam heating coils 

 (G) with intake, and outlet of steam; a circular, perforated pipe 

 (M) is installed near the top of the chamber for the purpose of dis- 

 charging into the chamber heated air, an atomizing jet (O 5 ) enters 

 through the side of the drying chamber near the top, an air pump 

 (O) forcing heated air into the atomizing nozzle (O 5 ), a slide door 

 (D) at the bottom of the drying chamber for the discharge of the 

 dried powder through opening (E), and a perforated covering (K) 

 over the top of the drying chamber for the escape of the moisture- 

 laden air. 



