Condensed Milk and Miek Powder 



5i 



fore the higher the atmospheric pressure, the higher must the con- 

 denser be above the cistern. At the sea level, the atmospheric pres- 

 sure sustains a water column about thirty-four feet high. This 

 water column in the discharge pipe seals the vacuum and at the 



same time it permits the water from the 

 spray and the condensation water to es- 

 cape automatically. The cistern in which 

 the water column terminates should be 

 of sufficient size to hold about one-third 

 more water than the capacity of the en- 

 tire length of the discharge pipe calls 

 for and should have a large overflow 

 into the sewer. When the pan is in 

 operation and a uniform vacuum is 

 maintained, the level of the water col- 

 umn remains constant and the excess 

 water from the condenser overflows 

 from the cistern into the sewer. 



The Wet-Vacuum Spray Con- 

 denser consists of a huge hollow cylin- 

 der of brass or iron, usually, but not 

 necessarily, horizontal. It is equipped 

 with a perforated spray-pipe placed 

 lengthwise through the center of the 

 cylinder. The spray pipe connects at 

 one end with the pipe supplying the 

 cooling water. When the pan is in 

 operation, a shower of 'cold water is- 

 sues forth from the perforations in the 

 spray pipe as the result of the reduced 

 pressure in pan and condenser. The 

 hot vapors arising from the boiling milk 

 in the pan are drawn over into the condenser, where they come in 

 contact with the cold water spray and are condensed. The bottom 

 of the condenser is connected with the suction end of the vacuum 

 pump, through which the water in the condenser escapes. 



The chief difference between the wet-vacuum condenser and the 

 barometric condenser is that, in the wet-vacuum condenser the water 

 from the condenser passes through the vacuum pump, while in the 

 barometric condenser the water does not pass through the vacuum 



Fig. 15. Barometric condenser 



Courtesy of 

 Buffalo Foundry & Machine Co. 



