PRINCIPLES OF NAVAL ENGINEERING 



PRESSURE GAGE 

 RELIEF VALVE 



r BYPASS VALVE 



-DESUPERHEATER DRiP 

 COMPRESSOR 



.VAPOR SEPARATOR 

 MANOMETER 



-VAPOR SEPARATOR DRAIN 

 CHECK VALVE 



BRINE 

 OVERFLOW 

 "-TUBE 



DRAIN 



FROM DESUPERHEATER TANK 

 FEED INLET- 



'VENT LINE 

 3/64" ORIFICE 

 -STEAM CHEST VENT 



CONDENSATE 

 OUTLET 



ELECTRIC HEATER -J 



/ 



^m^^^^^^^^^^^w\^^^^^^^ ^T"*!, 



, ,, ? li^ 



m^mm^^'f^^^^^ m^^^^^^^^^^ HEAT VFNT 



2^1^^ EXCHANGER OUTLET 



TRAP 



BRINE OVERFLOW OUTLET- 



FEED WATER 1 



CZD VAPOR AT ATMOSPHERIC PRESSURE 1 

 M22 COMPRESSED VAPOR 



Zl CONDENSATE 



^ CONCENTRATED 

 -*- FLOW PATHS 



BRINE 



Figure 18-3.— Schematic view of vapor compression distilling plant. 



75.287 



HEAT EXCHANGER. -The heat exchanger 

 preheats the Incoming sea water feed by two heat 

 exchange processes. In one process, the sea 

 water feed is heated by the distillate which is 

 being discharged from the distilling unit to the 

 ship's tanks. In the other process, the sea water 

 feed is heated by the brine overflow which is 

 being discharged overboard or to the brine col- 

 lecting tank. 



The heat exchanger is a horizontal double- 

 tube unit. Either sea water or brine flows 

 through the inner tubes, while distillate flows 

 through the space between the inner and the outer 

 tubes. 



Figure 18-4 shows the construction of the heat 

 exchanger and also illustrates the flow paths. 



454 



