An in-depth look at vibratory sieves and separators for dry bulk powders0 pages

RUSSELL FINEX
Russell Finex Ltd. UK Russell Finex N.V. Belgium Russell Finex Inc. USA
Tel: +44 (0) 20 8818 2000 Tel:+32 (0) 15 27 59 19 Tel:+1 704 588 9808
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Achieving faster speeds
Over the years, a few basic designs of vibratory separators
designed for grading materials have been developed.
One design incorporates a vibratory motor mounted on a
spring suspension. Because this design is quite simple to
manufacture, it is one of the most commonly available type of
separators.
An alternative is to employ a standard drive motor (i.e. not
vibratory) with a separate vibrator housing mounted on a rubber
suspension. Examples of such machines are the Finex
SeparatorTM and Finex 22TM from Russell Finex.
Most machines vibrate at 1400 rpm, but by separating the
motor from the rubber suspension in this type of design, it
became possible to increase the operating speed of the
machines up to 2800 rpm with high out-of-balance forces.
This development led to increased efficiency of the sieve,
enabling smaller diameter machines to be used without
adversely affecting performance. For example, a 22” diameter
machine operating at 2800 rpm can significantly out-perform
a 48” diameter machine operating at 1400 rpm on materials
which are traditionally difficult to screen.
An in-depth look at vibratory sieves and
separators for dry bulk powders
By Ray Singh, Sales and Marketing Director, Russell Finex Ltd.
In today's fast-paced, high-tech world, vibratory
sieves and separators for screening dry bulk powders
are sometimes perceived as rather low-tech
and old-fashioned. However, they are actually still
powerful tools for companies focused not only on
achieving the highest levels of product quality, but
also the bottom line.
Vibratory sieves and separators, also commonly
referred to as gyratory separators or screening
machines, are a traditional part of processing dry
bulk powders. They classify materials by separating
them by particle size through a screen mesh. Using
a combination of horizontal and vertical movements,
they spread the material over a screen in controlled
flow patterns and stratify the product.
There are several functions a vibratory sieve or
separator can achieve:
Check/safety screening- used for quality
assuance by checking for foreign contaminants
and oversized material and removing them from
the product.
Grading/sizing screening - used to grade or
classify material into different particle sizes.
Recovery screening - used to recover valuable
materials in the waste stream for re-use.
For many years, the majority of vibratory separators
had a rectangular or square design and employed a
simple reciprocating movement to classify the
powder.
During the early 1930's, machines that used gyratory
motion, i.e. small circular orbital movements, were
introduced. This then led to the use of circular
screens, which offered a much better usage of
screen area, and therefore an increased capacity
per unit mesh area.
Since then, in addition to the outward appearance of
sieving machines evolving, there have been major
advances in their component parts and in developing
machines for specific applications and/or
industries.
Finex SeparatorTM