EQUIPMENT MANAGEMENT
15
AGGREGATES MANAGER December 2014
D
ewatering screens were fi rst introduced
to the mining industry nearly 40 years
ago as a more effi cient means of dewater-
ing -1/4 inch solids contained in slurries.
In most operations, they replaced older technology
such as screws/spirals or rake classifi ers because
they delivered a drier product. W hile the Velco
dewatering screen was very common in the 1980s
for the U.S. coal industry, the aggregates industry
only really started adopting dewatering screen tech-
nology in the early 1990s, and, even then, it was
o en used following fi ne material screw washers to
improve the moisture content of the sand.
Dewatering screens are simple devices and most
o en use two counter-rotating vibrating mo-
tors (some use twin eccentric sha s) or multiple
mechanical exciters on larger machines, which
are mounted on a stressed relieved bridge. is
drive mechanism is most o en combined with
an upward inclined deck usually at 3 to 5 degrees
(but occasionally at 0 degrees, depending on the
application).
How some dewatering screens work (for upward-
ly inclined screens with counter rotating motors):
Wondering how to
cut the water in
your product? Learn
where and why
dewatering screens
may be the answer.
by John Best
Demystifying
Dewatering
Long used in coal mining, dewatering screens have become standard
equipment in many aggregate operations as well.
