VACUUM PA^'S. 



345 



main body, while the scum is held in the trough, until a sufficient quantity has gathered 

 to make it an object to ease the steam and wash out the trough. 



These vessels are also used as open steam evaporators, having an abundance of heat- 

 ing surface, plenty of high pressure steam, and proper openings for the escape of the 

 condensation; for the water must not be allowed to accumulate in the coils, if rapid aud 

 effective work is desired. 



The cuts show the necessary pipes and valves for the complete aud successful working 

 of the train. 



These vessels are also used for reducing the juice to a syrup of ij" B., preparatory for 

 the vacuum pan. 



