76 SWEETENED CONDENSED MILK CONDENSING 



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 finished condensed milk. It is 



further needed to prevent the contents of the vacu- 



um pan from being drawn over into the condenser, 



whenever the milk rises above a safe level. 



A further accessory of the dome may be an 

 automaotic milk sampler. The sampler tube is 

 carried through the wall of the dome and extends 

 to near the bottom inside of the pan. Where this 

 t .il:e projects through the dome it is equipped with 

 motor, piston pump, striking cup and hydrometer.' 

 The striking cup at its upper end terminates in a 

 small chamber equipped with a sight-glass through 



which the operator notes the position of the hydro- 



Thermometer 



meter. for vacuum pan 



The Condenser. 

 -The condenser is &c - 



that portion of the condensing ap- 

 paratus in which the vapors, rising 

 from the boiling milk in the pan, are 

 condensed to water. The condenser 

 is attached to the dome of the pan. 

 There are three types of condensers 

 in use, the surface condenser, the 

 barometric condenser and the wet- 

 vacuum spray condenser. 



The Surface Condenser consists 

 of a tube cylinder filled with brass 

 tubes, mounted on a receiver. The 

 water used for cooling circulates out- 

 side of the tubes and the vapors pass 

 Fig.. 24. through the tubes, where they are 



Vacuum breaker or blow-down chilled and condensed. This COn- 



Courtesy Arthf/Harris & Co. denser has the advantage of enabling 



the operator to note the amount of 



condensation and to measure the amount of water actually con- 

 densed. The receiver at the bottom of the condenser should be 



