Continuous Process Evaporators 



135 



baffle plate which extends across its cylindrical part and leaves 

 openings at both ends of the vapor body for the vapors to escape, 

 the ends or heads of the vapor body being dished outward. The 

 vapor body also carries the milk inlet, vapor outlet and spy 

 glasses. 



The steam chest which is attached to the lower part of the 

 vapor body, is divided by a solid partition into two compart- 

 ments. The upper and larger compartment is filled with tubes 

 which are expanded in the flue-sheets, closing both ends. The 

 tubes themselves are open at both ends. They are two inches 

 in diameter and from six to eight feet long. The lower and small 

 compartment, called the doAvntake, is entirely open at both ends. 

 The steam chest is equipped with a steam inlet, a liquor outlet 

 and a condensation outlet or drip. The steam is around the tubes 

 and the milk is inside the tubes. 



Operation.-— This machine is operated under vacuum of from 

 26 to 28 inches mercury column, the vapor outlet being connected 

 with a condenser and vacuum pump. 



The fluid milk 

 enters the vapor 

 body and flows down 

 into the bottom of 

 the downtake of the 

 steam chest, from 

 where it rises in the 

 tubes and finds its 

 level. The level of 

 the milk in the tubes 

 is kept low, the co- 

 effijcient of the heat 

 transmission being 

 highest when the 

 milk level in the 

 tubes is about one-third of the tube length above the lower flue- 

 plate, and it is regulated by automatic float controls in the larger 

 machines. The steam that is turned into the steam chest, causes 

 the milk in the tubes to boil. The vapor thus arising from the 

 milk, together with a portion of the milk rises and.passes through 



^ Vapor ootlet 



irtTERNAu Separator 



lonperuATiON OuikKi 



Liquor ootlct 



AMOCKAIM 



Fig. 51. Cross section of Buflovak 



rapid circuiation evaporator 



Courtesy of Buffalo Foundry & 



Machine Co. 



