felisa FE-390 Instructivo De Operación página 6

10
FEATURES.
All Stills are equipped with a decocentrator to continuously
deconcentrate impurities from the evaporator and retard scale formation.
A constant level device with hot well arrangement is provided for
evaporator water level control and for primary elimination of gaseous
impurities. All Stills are equipped with a drain valve, cooling water
discharge piping is provided between the cooling water outlet to the
condenser level device.
DECONCENTRATOR .
The function of the deconcentator is to maintain a minimum
concentration of dissolved impurities in the evaporator, thus reducing to
a minimum scale formation and tendency to foam. You have to adjusted
as follow.
A.- Permanent hard water or softened water: The valve should be left
open at all time, to bleed water from the evaporator at approximately 1.2
times the capacity of the Still. 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.
B.- Temporary hard water: If the feed water to the evaporator is high in
temporary hardness (high in bicarbonates) the valve should be closed.
The reason in that the bicarbonates in solution tends to precipitate at
temperatures up to 150 °F. With the deconcentrator valve open, a large
quantity of feed water passes through the evaporator, precipitating
bicarbonates, increasing the scale formation. Keeping the valve close,
will result in an increased concentration of solids in the evaporator,
thus create a tendency to foam. This condition is corrected by draining
the Still trough the drain valve at frequent intervals.