CHAPTER II. 



THE PASTEURIZING HEATER. 



Continuous Heater. 



In writing the history of the apparatus which have been 

 and are used practically, I try to mention them in their proper 

 chronological order, but lay more stress on grouping them to- 

 gether according to the principles involved. 



It must always be remembered that a pasteurizing ap- 

 paratus must consist of a heater and a cooler unless indeed 

 the same apparatus is used for both as in Prof. Russell's, John 

 Boyd's, Potts' and others. 



HEATER. 



. In Denmark the first 

 heater used was the one 

 constructed by the late 

 Prof. Fjord for heating 

 the milk for the separa- 

 tors Fig. 13. This con- 

 sists of a strong wooden 

 barrel D in which a 

 tinned copper vessel C is 

 inserted. A stirring ap- 

 paratus K prevents the 

 milk, which enters at M 

 through H, from scorch- 

 ing on the side. Steam 

 is introduced by F if ex- 

 haust and E if direct 

 steam is used. Con- 

 densed water escapes 

 through G. The milk 

 outlet not shown in the illustration, is above tl:e wood. \Yh< j n 



