THE PASTEURIZATION OF MILK 



as the "regenerative principle." This means that 

 the hot milk which flows from the machine is em- 

 ployed for warming the cold milk which flows into 

 the apparatus to be heated. When this regenera- 

 tive principle is used, a considerable economic sav- 

 ing of heat units is secured. This saving means 

 that less steam is required for heating, and also that 

 less ice is necessary for cooling. In the type illus- 

 trated in Fig. 4 the milk flowing from the holder 

 is conveyed to a holding apparatus, and after be- 

 ing held is returned to the heater, where it flows 

 through another compartment and helps to heat 

 the inflowing cold milk. 



At least one form of regenerative heater (Fig. 

 6) is so constructed that this intermediate holding 

 process cannot be used. In sections of the country, 

 therefore, where city regulations require that the 

 heated milk be held for a definite period, this form 

 of heater cannot be used. As a so-called "flash" 

 pasteurizer, this machine has given good results. 



In Fig. 4-B is shown a form of heater in which 

 the hot water is contained on the inside of the lower 

 cone. The milk flows from the top over the heated 

 cone. Revolving arms to which is attached a heavy 

 cord, keep the cone surface wiped, and prevent 

 54 



