AU663439B2 - Improvements to screening systems - Google Patents

Description

Regulation 3.2(2)

AUSTRALIA

Patents Act 1990 1663439

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT #411 ''44 its' 4 '4 if 4 f I.

lIft 4 5 4 144 4 Application Number: Lodged: l44~ t#e #440 4' #444 '5.4 it cc 4g I Invention Title: IMPROVEMENTS TO SCREENING SYSTEMS The following statement is a full description of this invention, including the best method of performing it known to us IMPROVEMENTS TO SCREENING SYSTEMS This invention relates to improvements to screening systems and in particular to the attachment of screening panels to support structures.

Screening panels are used extensively in the separation of particles of various sizes. For large scale separation, large screening areas are required. It is known to use a framework of struts as the support for a large number of individual panels which are fixed to a support frame rather than a single large screening surface. This makes it easy to replace individual screening panels as they become worn, rather than having to replace the complete screening 10 surface.

Australian Patent No. 482212 discloses such an arrangement whereby i the screening panels are fixed to the support struts which form a grid-like structure by a plurality of spigot-like protrusions which are spaced along the periphery of the screening panel. The support struts contain apertures of a suitable size which receive the spigot-like protrusions. These spigot-like .tL' protrusions are inserted in pairs into the apertures of the support struts and thus the screening panel is held in place. The use of screening panels comprising spigot-like protrusions is considered particularly useful when the separation of large particles or heavy media dewatering is required as there is virtually no movement of the screening panels due to the tight fit of the spigot-like protrusions in the apertures of the support struts. However, this type of arrangement can be a disadvantage when the screening panels require regular replacement as the firm fit of the spigot-like protrusions make removal of the screens from the apertures of the support struts difficult.

Australian Patent No. 517319 also discloses a screen deck comprising a support frame of struts in a grid formation upon which are placed screening panels. However, the panels are attached to the support frame by fastening devices inserted into the grooves located on projections of the screening panel.

When two panels are placed side by side such that two projections are inserted into an aperture of the support struts, the grooves of the projections form a bore into which a fastening means is inserted such that the projections are expanded in order that the screening panels are held in place.

2 This form of attachment of the screening panels to the support struts is used for dry screening or light screening. The use of this method of attachment is not suitable for screening large particles, because when the particles are dropped onto the screening panels, the fastening devices tend to pop out of the bores, leaving the screening panels unattached to the support struts. This method of attachment is also not suitable for screening wet mixtures because the introduction of fluid into the bore, between the side wall of the groove and the fastening device, leads to a small amount of movement, as the liquid may lubricate the fastening device.

~V 10 In use screening panels become worn and therefore replacement is required fairly regularly. Both these types of attachment (spigot-like protrusions and projections with grooves) of screening panels to support struts allow for the removal and replacement of the screening panels.

Spigot-like protrusions are considered a suitable and desirable means for attaching screening panels to support struts for heavy screening and heavy media dewatering whilst the use of fastening devices in a central bore of projections to attach screening panels to support struts is considered preferable when light or dry screening is required. This represents a general view of preferences to which there may be exceptions. In light duty, wet applications for example, the fastening device and bore system can be used although the C majority of sites of this type utilise the spigot like protrusions. Thus to carry out a full range of screening processes, it is generally considered necessary to have two screening systems, one using spigot-like protrusions to attach the screening panels to the support struts and another using projections attached by fastening devices.

It is an object of this invention to provide a screening system which is more adaptable and capable of use in the screening of all types of ores, across the full range of applications e.g. wet and dry, heavy and light.

To this end the present invention provides a screening arrangement comprising rigid, parallel support struts and screening panels attached thereto which abut one another so as to form a continuous screening surface, said struts incorporating apertures in which peripheral projections of said 3 screening panels are removably mounted, said peripheral projections located on two opposed sides of said screening panel comprising deformable spigot-like protrusions, and said peripheral projections located on other two opposed sides of said screening panel comprising a peripheral surface having a groove therein, such that when more than one projection is placed in an aperture of a support strut, a fastening device can be inserted into a central bore, such that the screening panels can be attached in one orientation to the support struts by either spigot-like protrusions or a fastening device inserted into 10 a central bore.

In general, the peripheral projections are directed transversely to the screening surface. Preferably, the peripheral projections are integral with the screening panel.

It is also preferable that the screening panels are square in shape.

It is particularly preferable that said deformable spigot-like projections and said peripheral projections comprising a peripheral surface having a groove therein are of a suitable size such that said apertures in said struts are all one size.

It is also particularly preferred that the support struts are arranged in a longitudinal manner.

r By utilising parallel support struts extending in the direction of ore flow, cross frame members are eliminated. Corrosion and abrasion of these cross members has been a; problem in full frame screening syotems. A system of parallel, longitudinal struts to which the screening panels are attached is disclosed in Australian Patent No. 525477. The screening panels described therein have projections on the two longitudinal peripheries only and the fastening means disclosed for such a system is a projection requiring the insertion of a fastening device.

The invention also provides a screening panel having on two opposed peripheries, deformable spigot-like protrusions being directed transversely to a screening surface and being integral with said screening panel, -w 4 and having on the other two opposed peripheries projections comprising a peripheral surface having a groove therein, said projections being directed transversely to the screening surface and being integral with said screening panel.

It is preferred that the screening panel comprises spigot-like protrusions and projections comprising a peripheral surface having a groove therein which are of a suitable size such that they fit into apertures of the same size.

Thus the invention provides for a screening system whereby it is quick and easy to change the method by which the screening panels are attached to the support struts in order to allow for the different types of screening required.

This results in reduced cost and a lower inventory and also increased efficiency in the use of the screening panels. The system also retains the flexibility of allowing for the replacement of screening panels as they become worn without disturbing the surrounding screening panels.

The preferred embodiment of the invention will now be described with reference to the figures in which: Figure 1 is a perspective view of a screening arrangement and Figure 1(a) shows a cross section of the screening arrangement; Figure 2 is a perspective view of an individual screening panel; Figure 3 is a side view of an individual screening panel along one r peripheral edge; and Figure 4 is a side view of an individual screening panel along an adjacent peripheral edge to that shown in Figure 3.

Figure 1 shows a screening arrangement comprising support struts (1) and numerous individual screening panels attached to the support struts (1) by projections containing grooves. In the alternative the screening panels (2) may be attached to the support struts by spigot-like protrusions The support struts are generally constructed of a rigid material which may be protected against corrosion by suitable coatings and have suitably spaced apertures along their length. The support struts are arranged in a parallel and preferably longitudinal manner and are attached to a support structure (not shown) by any suitable means.

The individual screening panels which are preferably square in shape are attached to the support struts in such a manner that they abut one another so as to form a continuous screening surface. The screening panels are generally made of a resilient plastic material and preferably are produced by injection moulding so that they are very dense and are therefore resistant to wear. The surface of the screening panel as shown in Figure 2, comprises a series of apertures across its surface which allow selected particles through on the basis of size of the particle. The size and shape of the aperture of the screening panel can be varied considerably depending 10 upon the type of screening that is required.

C€cr C. ;The screening panel is fixed to the support struts by spigot-like S" protrusions or projections containing grooves on their peripheral surface The spigot-like protrusions are located on two opposed peripheries (10) of thp'screening panel whilst the projections are located on the other two opposed peripheries (11) of the screening panel. Both the spigot-like protrusions and the projections are preferably deformable, are directed transversely to the screening surface and are integral with the screening panel Preferably, the spigot-like protrusions and the projections on the screening panel are of a size such that they are both suitable for insertion into apertures of the same size. The number of peripheral projections on the peripheries of the screening panel may vary upwards from at least one per side.

The spigot-like protrusions or the projections can be inserted into the apertures in order that the screening panels may be attached to the support struts If it is desired to attach the screening panels to the support struts by the spigot-like protrusions as shown in Figure 3, the screening panels are placed in the appropriate orientation and two spigot-like protrusions from adjacent screening panels are inserted into the apertures of the support struts such that the screening panels cannot move.

If it is desired to attach the screening panels to the support struts by the projections as shown in Figure 4, the screening panels are placed in I nu~~i; nly 6 the appropriate orientation and two projections from adjacent screening panels inserted. The central bore (12) that results from the grooves of the peripheral surface of the projections has a fastening device (13) inserted such that the screening panel is immobilised in position on the support struts The fastening device (13) may be in the shape of a pin but any other suitable shape may be used.

This invention makes it possible to carry out screening of different types of ore by using one screening panel instead of two which vary in the type of attachment used to attach the screening panel to the support struts. This is I 10 possible because the form of attachment to the support struts can be varied quickly and easily.

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Claims (7)

1. A screening arrangement comprising rigid, parallel support struts and screening panels attached thereto which abut one another so as to form a continuous screening surface, said struts incorporating apertures in which peripheral projections of said screning panels are removably mounted, said peripheral projections located on two opposed sides of said screening panel comprising deformable spigot-like protrusions, and said peripheral projections located on other two opposed sides of said screening panel comprising a peripheral surface having a groove therein, such that when more than one projection is placed in an aperture of a support strut, a fastening device can be inserted into a central bore, such that the screening panels can be attached in one orientation to the support struts by either spigot-like protrusions or a fastening device inserted into a central bore.

2. A screening arrangement as claimed in claim 1 wherein said peripheral projections are directed transversely to the screening surface and are integral with said screening panel.

3. A screening arrangement as claimed in claim 1 or claim 2 wherein the support struts are arranged in a longitudinal manner.

4. A screening arrangement as claimed in any one of claims 1 to 3 wherein said deformable spigot-like projections and said peripheral projections comprising a peripheral surface having a groove therein are of a suitable size such that said apertures in said struts are all one size.

A screening arrangement as claimed in any one of claims 1 to 4 wherein two projections of the same type from abutting screening panels are inserted into one aperture of the support struts such that the screening panels are 8 removably attached to the support struts.

6. A screening panel having on two opposed peripheries, deformable spigot-like -protrusions being directed transversely to a screening surface and being integral with said screening panel, and having on the other two opposed peripheries projections comprising a peripheral surface having a groove therein, said projections being directed transversely to the screening surface and being integral with said screening panel. S t SC t V oo

7. A screening panel as claimed in claim 6, wherein the spigot-like S' protrusions and the projections comprising a peripheral surface having a groove cc t S therein are of a suitable size such that they fit into apertures of the same size. S DATED THIS 7th DAY OF APRIL, 1994 RICHARDSON PACIFIC LTD. S" WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM 290 BURWOOD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA DBM:CJH:JC:SH DOC34 AU000470.WPC f i r I ii I i I L t ABSTRACT This invention relates to screening arrangement comprising rigid, parallel support struts and screening panels attached thereto which abut one another so as to form a continuous screening surface, said struts incorporating apertures in which peripheral projections of said screening panels are removably mounted, said peripheral projections located on two opposed sides of said Sscreening panel comprising deformable spigot-like protrusions, and said peripheral projections located on other two opposed sides of said Sscreening panel comprising a peripheral surface having a groove therein, such that when more than one projection is placed in an apertuir of a support strut, a fastenin- device can be inserted into a central bore, isuch that the screening panels can be attached in one orientation to the support struts by either spigot-like protrusions or a fastening device inserted into a central bore. The invention also relates to a screening panel having on two opposed peripheries, deformable spigot-like protrusions being directed transversely to a screening surface and being integral with said screening panel, and having on the other two opposed peripheries projections comprising a peripheral surface .'aving a groove therein, said projections being directed transversely to the screening surface and being integral with said screening panel. 'l I