76 SWEETENED CONDENSED M1iLK—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. 
\ 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 
i ile 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 
; a Fig. 22 
which the operator notes the position of the hydro- - 
: Thermometer 
meter. for vacuum pan 
The Condenser. _,Cgirtesy of 
—The condenser is & Co. 
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 evlinder 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- 
valve 
Courtesy Arthur Harris &Co, ‘lenser 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 
