23 



believe it is rather an advantage while it is heating arid during the 

 first cooling, as it will drive out many taints which have not a bacter- 

 iological origin. Dur- 

 ing the last cooling it is 

 safer to have the surface 

 protected. If the milk 

 is perfect, it is better to 

 exclude the air as much 

 as possible. 



SURFACE HEATERS 



WITH MILK PRO= 



TECTED. 



*CARL THIEL " 

 as early as 1886 adopted 

 a system of heater Fig. 

 19 where the milk is not 

 exposed to the open air. 

 It consists of a tinlined 

 wooden cylinder a be- 

 tween which and a cor- 

 rugated cylinder is a 

 perforated steam coil o 

 with steam entering at 

 h thus heating the 

 water to the desired 

 temperature read off on 

 the thermometer b. 

 The overflow water es- 

 capes at p and is emp- 

 tied at n. 



The milk flows from 

 the tank x on to the 

 curved cover which is 

 perforated so as to dis- 

 tribute the milk evenly 

 on the upper corrugation from whence it flows to the bottom and out 

 by i and k, the thermometer m showing its temperature, 



Dr Fleishman heated 1250 Ibs. of milk per hour from 66 to 140 

 Fah. with the heating water only 158. 



Fig. 18. 



