14
Deconcentrator Adjustment
The function of the deconcentrator is to maintain
a minimum concentration of dissolved impurities
in the evaporator, thus reducing scale formation
and tendency to foam to a minimum. The decon-
centrator is adjusted as follows:
1.
Permanent Hard Water or Softened
Water (Softened feed is not
recommended).
The deconcentrator
valve should be left open at all times to
bleed water from the evaporator at ap-
proximately 1-1/2 times the capacity of
the still. This valve should be left open
permanently at the required setting.
Care should be exercised to see that it
is never clogged. The valve should be
inspected periodically and if required,
disassembled and cleaned with a brush
or scraper.
2.
Temporary Hard Water.
If the feedwater
to the evaporator is high in temporary
hardness, i.e., high in bicarbonates, the
deconcentrator valve should be closed.
The reason for this is that bicarbonates
in solution tend to precipitate out at tem-
peratures exceeding 150°F. With the
deconcentrator valve opened, a larger
quantity of feedwater passes through the
evaporator, precipitating out
bicarbonates, increasing the amount of
scale formed. Keeping the to 150°
deconcentrator closed will result in an in-
creased concentration of solids in the
evaporator as time goes on, thus
creating a tendency to foam. This
condition is corrected by draining the still
through the drain valve at frequent
intervals.
3.
Demineralized Water
When demineralized water is used as
feedwater the deconcentrator valve may
be kept closed.
O
PERATION
