An Improved Material Screening Device
Field of Invention:
This invention relates to an improved material screening device for screening /
separating or grading of minerals in the mining and quarrying industries.
Background of the Invention:
A modular screening panel system for ore screening decks that is now widely used
by the mining industry and replaced the earlier screening cloths and large wire
screening frames. The screening panels are of modular design with a size of either
305 x 305 mm or 610 x 300 mn made of polyurethane / Rubber with steel
reinforcements. The panel is cast, injection moulded or vulcanized elastometric
material, preferably polyurethane. The panels are adapted to be secured with the
support frame of the screen machine. The panels are secured on projected buttons
on the supporting frame and are forced fit in the corresponding female parts in the
panels. This has been disclosed in the applicant's co-pending patent application
176/CAL/2002.The panels may also be secured to the frame with an alternate
method using a pin and separate lug arrangement.
A difficulty encountered in using these panels is that the screening apertures can
become clogged with near size materials failing to pass through the apertures. If a
large section of the panels is affected n this way it is said to be blinded resulting in
drop of the screening efficiency. Blinding of screening panels is most prevalent in dry
screening where there is no water to wash out the apertures and where the aperture
size is below 10 mm. Problems are encountered also in dry screening where the
moisture content in the ore is high enough to encourage agglomeration of ore fines.
Therefore, there is a constant need for a screen panel, which can overcome the
above deficiencies.
Objects of the Invention:
It is the primary object of the invention to provide a screening device whose screen
panel apertures do not clog while material sieving/screening operation.
It is another object of this invention to provide a screening device for screening
mineral, which is self-cleaning.
It is yet another object to provide a screening device capable of being continuously
used in material screening operation.
The above and other objects of the nvention will be further elucidated by the
following detailed description of the invention with respect to the drawings.

Summary of the Invention:
Accordingly the present invention provides a screening device comprising at least
one sieve screen panel detachable attached to the screen support frames, said
screen panel comprising a plurality of predetermined shaped individual apertures
being fused together to form continuous apertures, and thereby forming a plurality
of individual ribs between the two longitudinally adjacent continuous apertures,
extending across the length of the panel, said plurality of individual ribs being
adapted to be spaced apart from each other by said continuous apertures, on the
surface of said screen panel.
The plurality of ribs are capable of being deformed depending on the material to be
sieved.
The plurality of apertures is adapted to be flared downwards with respect to the
surface of the panel.
Preferably said plurality of apertures is polygonal or circular in shape.
Preferably said apertures are diamond shaped.
Said plurality of individual ribs is zigzag shaped.
Preferably, number.of said apertures is different in longitudinally adjacent ribs.
Preferably, surface of the screen panel is made of polyurethane or vulcanized
elastomeric compound with metal embedded therein.
The downwardly flared plurality of predetermined shaped apertures is adapted to
cause secondary vibration on the screen panel.
Brief Description Accompanying Drawings:
The invention is now described with reference to the accompanying drawings, in
which
Figure 1 shows a plan view of the screening surface in accordance with the invention.
Figure 2 shows a side view of the screening element of Figure 1.
Figure 3 shows a fragmentary plan view of a screen deck in position on a support
frame.
Figure 4 shows on enlarged scale a fragmentary plan view of the deformation of ribs
shown in screening element of Figure 1.
Detailed Description of the Invention:
The present invention discloses a flexible one-screening panel adapted for mounting
on a screening deck, which includes a screening surface integrally formed on a
reinforcing frame. The inventive screening device for screening mineral ores
comprising a screening surface having greater flexibility at the periphery of each

aperture.This is achieved by providing zigzag ribs extending across the panels to
define screening aperture. The self-cleaning action is thus dependant on the shape
and arrangement of the apertures in the screening surface.
Referring to Figure 1 and 2 of the drawings reference numerical (10) indicates in
general a screening element in the form of a pane, made of polyurethane having a
shore hardness of 80-90, depending on the material to be screened. The panel has
zigzag adjacent ribs (30) not connected to each other. The zigzag adjacent ribs
define the continuous apertures (2)) in between, which is actually a plurality of
apertures of predetermined shapes, e.g polygonal, circular, diamond shaped, being
fused together, so as to make a continuous aperture (20) with a special geometry.
The boundary of the two longitudinally adjacent continuous apertures (20) makes a
zigzag shaped individual rib (30) formed there between. Accordingly two
longitudinally adjacent ribs are separated by the continuous aperture (20) located in
between.
Fig 3 is fragmentary view of the screening deck including the screen panel fixed on a
support frame.
As shown in Figure 4 of the accompanying drawing, the ribs are deformable as well
as are flexible. Since the adjacent ribs are not connected to each other the
gravitational force exerted by any particle that gets stuck within the continuous
aperture (20) forces the two adjacent walls to be deformed outwardly. This in turn
actually stretches the aperture area a lowing the stuck material to pass through the
apertures (20). Moreover, as shown n Figure 2, the apertures are designed to be
flaring downwards with respect to the screen surface. This helps in further
elimination of clogging in the apertures.
Preferably, the number of said ind vidual apertures in a particular continuous
aperture (30) is different from that in longitudinally adjacent continuous aperture.
The panel is cast, injection moulded cr vulcanized elastometric material, preferably
polyurethane, having embedded withir it steel reinforcing bars at the outer edges of
the panels and extended across the inner area of the panel to provide support to the
screening surface. In this arrangement the zigzag apertures are not connected to the
adjacent ribs, which has a dramatic effect on the ability of the screening surface to
be self-cleaning. The surface is able to flex and give a secondary vibration to the
apertures. This flexibility and vibration of the apertures will help the near size
materials to pass through the apertures easily. In case of sticky materials since the
apertures are flexible and provide a secondary vibration with differential movement it

disallows and breaks any caking of the material to some extent thereby increasing
the screening efficiency.
The invention has been described with the help of an exemplary embodiment only.
However, it will be readily construed by a person skilled in the art that several
modifications and improvements are possible without departing from the scope and
spirit of the invention as described hereinbefore and defined in the claims
hereinafter.

We Claim:
1.A screening device comprising at least one sieve screen panel detachably attached
to the screen support frames, said screen panel comprising a plurality of
predetermined shaped individual apertures being fused together to form continuous
apertures (20), and thereby forming a plurality of individual ribs between the two
longitudinally adjacent continuous apertures (30), extending across the length of the
panel, said plurality of individual ribs being adapted to be spaced apart from each
other by said continuous apertures, on the surface of said screen panel.
2.A screening device as claimed in claim 1,wherein said plurality of ribs are capable
of being deformed depending on the material to be sieved.
3.A screening device as claimed in claim 1 or 2, wherein the said plurality of
continuous apertures are adapted to be flared downwards with respect to the surface
of the panel.
4.A screening device as claimed in any preceding claim, wherein said plurality of
individual apertures is polygonal or circular in shape.
5.A screening device as claimed in claim 4, wherein said apertures are diamond
shaped.
6.A screening device as claimed in any preceding claim, wherein said plurality of
individual ribs is zigzag shaped.
7.A screening device as claimed in claim 1, wherein number of said individual
apertures in a continuous aperture is different from that in longitudinally adjacent
continuous aperture.
8.A screening device as claimed in any preceding claim, wherein said surface of the
screen panel is made of polyurethane or vulcanized elastomeric compound with
metal embedded therein.
9.A screening device as claimed in any preceding claim, wherein plurality of
predetermined shaped apertures are downwardly flared to cause secondary vibration
on the screen panel.

10.A screening device comprising plural ty of screen panels as claimed in claims 1-9.
Dated this 1st day of January 2009

The present invention discloses a screening device comprising at least one sieve
screen panel detachably attached to the screen support frames, said screen panel
comprising a plurality of predetermined shaped individual apertures being fused
together to form continuous apertures (20), and thereby forming a plurality of
individual ribs between the two longitudinally adjacent continuous apertures (30),
extending across the length of the panel, said plurality of individual ribs being
adapted to be spaced apart from each other by said continuous apertures, on the
surface of said screen panel.