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The still consists primarily of a boiler or evapora-
tor which holds the water during the evaporation
process; electric heating elements of the
immersion type inserted in the evaporator to boil
the water; and a condenser which condenses the
steam from the boiler to form the distillate.
The water to be purified enters the condenser
where it is heated by the steam passing through
the evaporator. The preheated water is fed to the
evaporator as required by the constant level
device which maintains the proper water level in
the evaporator. An overflow connected to the
drain is provided for the excess cooling water.
Water in the evaporator is vaporized by the
electric heating elements. The steam passes up
through the vapor pipe into the condenser where
it is condensed to distilled water. The condenser
is vented to atmosphere to eliminate the gaseous
impurities. All stills are equipped with a decon-
centrator and an extra high evaporator to permit
operating a still from hard water supplies. The
deconcentrator automatically maintains a mini-
mum concentration of dissolved impurities in the
evaporator, thus reducing to a minimum the scale
formation and tendency to foam.
Theory of Operation
Figure 5
Atmospheric
Vent
Inclined
Condenser
Cooling Water/
Feedwater
Inlet
Q Baffle
Double Walled
Evaporator
Immersion Heaters
(For Electric Stills)
Drain Valve
Constant Level
Device
Deconcentrator
Valve
Preheated
Feedwater
Distillate
Outlet
