Condensed Miek and Mii,k Powder 



49 



Fig. 12. Vacuum gauge 



Courtesy of Arthur Harris & Co. 



the milk shoots straight across the pan atomizing into a dense spray, 

 which is partly drawn over into the condenser, causing loss of milk. 

 The Dome rests on top of the body of the pan. It is equipped 

 with a manhole, manhole cover, thermometer, vacuum gauge, eye 

 glasses, lights and blow-down valve, or vacuum breaker. The man- 

 hole measures about fourteen to 

 eighteen inches in diameter. It is 

 closed by a solid brass cover with 

 a well fitting, ground-surface 

 flange. The cover carries a five 

 inch eye glass or sight-glass 

 through which the operator watch- 

 es the boiling milk in the pan. 

 The stem of the thermometer is 

 enclosed in a brass casing and 

 reaches to near the bottom of the 

 pan. Some processors prefer a 

 short thermometer which registers 

 the temperature of the vapors instead of that of the milk. As both, 

 the milk and the vapors are subjected to the same pressure, their 

 respective temperatures are the same. The long-stem thermometer, 

 the bulb of which is submerged in the milk, however, 

 is more sensitive and registers changes of tempera- 

 ture more rapidly, because the milk is a better con- 

 ductor of heat than the vapors. The vacuum gauge 

 connects with the interior of the pan, and indicates 

 the number of inches of vacuum. A mercury col- 

 umn may be used in the place of the vacuum gauge. 

 In the rear of the dome there are two eye glasses. 

 Through these the interior of the pan is illuminated 

 by means of lamps, gas or electric lights. The "blow 

 down" valve, or vacuum breaker, serves to admit 

 air into the pan in order to "break" the vacuum. 

 This is necessary for readily drawing off the fin- 

 ished condensed milk. It is further needed to pre- 

 vent the contents of the vacuum pan from being 

 drawn over into the condenser, whenever the milk 

 rises above a safe level. 



Fig. 13. 



Thermometer 



for vacuum pan 



Courtesy of 



Taylor 



Instrument Co. 



