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The Vibroscreen
is a circular unitised gyratory screen. It is the largest of its
type available today, with three-component multiplane mechanical
vibration with very high screening. It handles wet & dry screening
particles ranging from 10mm to 400 mesh size. It gives very high
capacity per sq.ft of screening area & consumes minimum energy.
The motivation is through a motor with a double extended shaft,
fitted at both ends with eccentric weights. The whole drive assembly
is mounted on a circular base by rugged springs which allow the
unit to vibrate freely, and at the same time, the springs prevent
transmitted vibration reaching the floor area on which the machine
stands. Screens can be mounted one on top of the other within
the screening assembly. The Vibroscreen is suitable for all types
of screening operations within these four broad catagories:
Dry Separation
Division of different materials on the basis of their particle
shape.
Dry Classificatin
Division of materials into precise sized fractions.
Solid-Liquid-Separation
Dewatering of solids and clarification of liquids.
Solids Classification
Separation of sized fractions in a liquid medium. Highest screening
efficiency is achieved by controlling the patterns of movement
of solids on the screen surface. Control is achieved by varying
the position of the bottom eccentric weight as shown in the diagram.
The material is fed on to the centre of the top screen and
the oversize material is moved by the multiplane motion to the
periphery of the screen to be discharged through a tangential
outlet. The undersize particles and / or liquids pass through
the screen to produce fine sized fractions or clarified liquid.
The tangential component of the motion-imparted to the solid on
the screen is controlled by the angular position of the top and
bottom eccentric weights. The screening pattern can therefore
be controlled by altering the angle of the eccentrics and some
general examples of the type of control are shown...
If the mass of the top eccentric is increased, this will increase
the horizontal throw on the screen and will cause the oversize
material to discharge at a faster rate.
An increase in the bottom eccentric mass will increase the vertical
component of the motion. In the case where 'near size' blinding
of the screen is a possibility, it is desirable to promote maximum
vertical motion in order to dislodge particles which may be held
(pegged) in the interstices of the screen.
High Capacity, Minimum Space
By varying the angular displacement of the bottom eccentric
weight, the screening pattern can be optimised for each job,
thus giving a high capacity per square foot of screen surface.
Adaptability
Discharge ports can be rotated to meet layout requirements and
individual frames between screen desks can be tailored to suit
the needs of that fraction.
No Transmitted Vibration
Motion is transmitted through the screening assembly and vibration
is completely absent from the screen base. No special foundations
are required and many screens are operating suspended from ceiling
hangers. By the same token, the machine can be made portable
and its operation is silent.
Long Screen Life
Sharples have developed a special screen holding device anda
taut screen cloth is achieved on assembly. The cloth does not
flex and moves rigidly with the screen assembly.
Minimum Screen Blinding
The vertical component of the vibration given by the bottom
eccentric weight ensures that blinding of the screen by particles
close in size to the screen cloth aperture is minimised. Ball
trays/Kleen Rings can be added if necessary to alleviate screen
blinding.
Low Operating Costs
The Vibroscreen uses only low power motors, since all their
energy is used to create screen motion, none is wasted in vibrating
a massive frame and foundation.
Bottom Eccentric Lead
The tangential component of the motion imparted to the solid
on the screen is controlled by the angular position of the top
and bottom eccentric weights. The screening pattern can therefore
be controlled by altering the angle of the eccentrics and some
general examples of the type of control are shown...
Large or small, wet or dry, there is a place for Vibroscreens
in your industry. Detailed below are some of the uses that Vibroscreens
have been put to. All Sharples machines are backed by a full
technical advisory service to help solve separational problems
in industry.
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