See also our terminology/definitions
page
What is a Hydrocyclone?
A hydrocyclone is a static device that applies centrifugal
force to a liquid mixture so as to promote the separation
of heavy and light components.
The hydrocyclone is a closed vessel designed to convert
incoming liquid velocity into rotary motion. It does this
by directing inflow tangentially near the top of a vertical
cylinder. This spins the entire contents of the cylinder,
creating centrifugal force in the liquid. Heavy components
move outward toward the wall of the cylinder where they
agglomerate and spiral down the wall to the outlet at
the bottom of the vessel. Light components move toward
the axis of the hydrocyclone where they move up toward
the outlet at the top of the vessel.
Hydrocyclones are also related to centrifuges in that
both are intended to separate heavies and lights by application
of centrifugal force to liquids. The key difference is
that hydrocyclones are passive separators capable of applying
modest amounts of centrifugal force, whereas centrifuges
are dynamic separators that are generally able to apply
much more centrifugal force than hydrocyclones. Another
key difference between hydroclones and centrifuges is
cost. Centrifuges are expensive precision rotating machines
that often need sophisticated control, whereas hydrocyclones
have no moving parts and usually no controls at all so
they are lower cost devices.
Hydrocyclones and centrifuges are complementary rather
than competing devices. If gravity alone will settle a
significant portion of your solids in a minute or two
using a quick bottle test, you should investigate hydrocyclone
separation. If settling takes much longer than this, then
you may need a centrifuge or other separation method.
See the Hydrocyclone
separation theory page for more information.
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What are the uses and limitations
of Hydrocyclones?
A hydrocyclone is most often used to separate "heavies"
from a liquid mixture originating at a centrifugal pump
or some other continuous source of pressurized liquid.
A hydrocyclone is most likely to be the right choice for
processes where "lights" are the greater part
of the mixture and where the "heavies" settle
fairly easily.
Generally, hydrocyclones are used in continuous flow
systems so that the instantaneous liquid inflow to the
hydrocyclone is equal to the total instantaneous outflow
of "lights" plus "heavies". In cases
where "heavies" are a very small part of the
whole liquid, it is sometimes advantageous to accumulate
them in the bottom of the hydrocyclone for batchwise removal.
ChemIndustrial's modular construction methods make it
easy for us to provide accumulation configurations.
In some applications, ChemIndustrial hydrocyclones are
capable of sharp separations of "heavies" and
"lights". In other situations, they are used
for incremental enrichment, reducing the load on other,
more costly separation equipment and improving the overall
economics of operation.
Hydrocyclones are generally not recommended for removing
long fibers from liquids.
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