AU770500B2 - Rider bar screen panel - Google Patents

Description

WO 01/45867 PCT/AU00/01211 1 RIDER BAR SCREEN PANEL This invention relates to a screen panel for a screening machine and in particular to screen panels for screening of fines such as coal fines and also for dewatering applications.

Screen panels for screening machines which include rider bars are known and generally the rider bars define a relatively large aperture. Generally the aperture is defined between adjacent rider bars and the aperture of the screen is defined by the minimum distance between adjacent rider bars which minimum distance is located at the upper most extremity of the rider bars.

Conventional screen panels which include rider bars suffer from the disadvantage of blinding by particles which are being separated by the screening machine entering the aperture and becoming stuck in the aperture. Furthermore, since the aperture is defined at the uppermost extremity of the rider bars, wearing of the rider bars by large particles contacting the rider bars decreases the life expectancy of the panels because the wearing can change the aperture size as the rider bars wear down thereby requiring regular replacement of screen panels on the screening machine.

If screen panels employing conventional rider bar configurations are used for fines rather than larger particulate material, the possibility of blinding by the fine particles is greatly increased.

The object of the present invention is to provide a rider bar screen panel which overcomes these problems and is useful in the screening of fines and in particular coal fines and for dewatering applications.

2 The invention may be said to reside in a screen panel for screening of fines or for dewatering of material, comprising; a plurality of rider bars arranged in side by side relationship and defining spaces therebetween for the screening of the fines or for the flow of water between the rider bars; the spaces between adjacent rider bars defining apertures with an aperture size of the apertures being defined by the distance between points on adjacent rider bars which are closest together; a head portion on each rider bar extending upwardly, having regard to the orientation of the screen panel when located on a screening machine, from the plane of the apertures, the head portion being in the form of a dome of substantially semi-circular profile in crosssection perpendicular to the longitudinal axis of the rider bar, so that the space between adjacent head portions and above the apertures tapers outwardly from the apertures; and each rider bar has a lower portion below the plane of the apertures which is defined by side surfaces which taper towards one another so that the space between adjacent lower portions tapers outwardly from a position 25 adjacent the apertures to a lower most extremity of the lower portion of the rider bars.

Thus, according to the present invention the apertures are defined below the uppermost extremity of the rider bars and 30 have a lead in channel defined by the curved profile above the apertures. The panel according to the invention provides for greater wear life because any wear of the rider bars takes place above the aperture and therefore wear of the rider bars does not alter the aperture size o 35 thereby increasing the life expectancy of the panel.

Furthermore, the curved profile provides a lead in channel for material or water to find the aperture and also H:\Lisa\Keep\Speci\Me1wire PCT-AUOO-01211-Amendments.doc 29/12/03 3 provides minimal point contact of particles thus preventing excessive blinding or pegging as particles larger than the aperture size can easily dislodge themselves and are also tended to be reflected away from the aperture in view of the curved profile of the head portion rather than becoming stuck in the aperture or the channel which leads into the aperture.

Preferably the rider bars are interconnected by a plurality of support members which extend transverse with respect to the rider bars.

Preferably the screen panels have connection means for connecting the screen panels to a screening machine.

The connection means may comprise semi-circular recesses and semi-circular bush members on sides of the screen panels so that when two screen panels are placed in side by side relationship the recesses and bushes form opening through which a pin can be connected so as to couple the screen panels to a screening machine.

Other forms of connection may also be used including the deformable legs or rails on the screen panels which are 25 deformed by a retaining member inserted between panels so that the deformable legs or rails engage a frame member of the screening machine to lock the panels to the screening machine.

o A preferred embodiment of the invention will be described, by way of example, with reference to the accompanying drawings in which; Figure 1 is a plan view of a screen panel, 0o*o o H:\Luisa\Keep\Speci\Melwire PCT-AU00-01211-Amendments.doc 29/12/03 WO 01/45867 PCT/AU00/01211 4 according to the preferred embodiment of the invention; Figure 2 is a view from beneath of the screen panel of Figure 1; Figure 3 is a cross-sectional view along the line 3-3 of Figure 1; Figure 4 is an enlarged view of part of the cross-section shown in Figure 3; and Figure 5 is a cross-sectional view through an embodiment of the invention.

With reference to Figure 1 a screen panel 10 is shown which is defined by a plurality of rider bars 12. The rider bars 12 extend generally parallel with respect to one another and are interconnected by support members 14 which extend perpendicular to the rider bars 12. The support members 14 and rider bars 12 can be. formed in a single moulding operation from polyurethane material.

The screen panel 10 may have a peripheral frame section (not shown in Figure 1) which includes connecting members for enabling connection of the screen panel to a screening machine. Such connection members are well known and therefore need not be fully described in detail herein.

Suffice to say that such connection members can include semi-circular recesses and semi-circular bosses which, when two panels are connected together form openings through which a pin can pass to secure the panel to a screening machine (not shown), or deformable leg members on the periphery of the panel which, when two panels are located in side by side relationship define a space for receiving a retaining member which deflects the leg members beneath rail members on the screening machine to lock the panel to the screening machine.

As is best shown in Figures 3 and 4 the rider bars 12 have a domed head 16 which is preferably, in cross-section perpendicular to the longitudinal axis of the rider bars WO 01/45867 PCT/AU00/01211 5 12, semi-circular in shape. The domed head 16 define curved profiles 17 which are adjacent one another in adjacent rider bars 12 so that the curved profiles 17 define a lead in channel for particulate material or for water which leads into space 20 defined between the rider bars 12. The space 20 between two adjacent rider bars 12 defines an aperture through fines below a predetermined size can pass so that those fines can be separated from other material by the screen panel 10. The aperture size is defined by points on adjacent rider bars 12 which are closest together as shown by the points A in Figure 4.

Thus, the rider bars 12 shown in Figure 4 define an aperture 12 between the points A which is of a predetermined size such as 1.25 mm, for example, for the screening of coal fines.

As is evident from Figure 4 the aperture 22 is positioned below the uppermost extremity 24 of the rider bars 12 and is close to upper surface 28 of the support member 14. In some embodiments, and if desired, the aperture 22 may in fact be substantially level with the upper surface 28 of the support members 14.

The space 20 between adjacent rider bars 12 below the aperture 22 is defined by side walls 30 of two adjacent rider bars 12. As clearly shown in Figure 4 the side walls of each rider bar 12 taper inwardly from the aperture 22 to a lowermost extremity 34 of the rider bars. Thus, a lower portion 25 of the rider bars 12 below the domed head 16 is of generally fustro-conical shape and the space below the aperture 22 tapers outwardly from the aperture 22 to the lowermost extremity 34 of the rider bars 12.

The rider bars 12 are firmly supported by the support members 14 and form generally rigid structures which do not bend or flex thereby maintaining the predetermined size of the aperture 22.

WO 01/45867 PCT/AU00/01211 6 When particulate materials such as coal fines is applied to the screen panels 10 and the screening machine on which the screen panels 10 operated so that the panels 10 generally vibrate or oscillate on the machine the fines which are below the aperture sides 22 (that is have a size of generally less than 1.25 mm) pass through the apertures 22 whilst larger particles are retained above the screen panels 10 for collection at one side of the screening machine.

The configuration of the rider bars 12 shown in Figure 4 provides protection to the size of the aperture 22 by keeping larger particles away from the aperture 22 and also allows for greater wear life as wearing of the panel will occur at the uppermost extremity of the domed head 16 or at least above the aperture 22 thereby increasing the life expectancy of the panels without deterioration of the aperture size 22.

The curved profile 17 between adjacent rider bars 12 provided by the domed head 16 provides a lead in channel for material and moisture to find the aperture 22. The curved profile also provides minimal point contact of the particles thus preventing excessive blinding or pegging of the aperture 22 as large particles can easily dislodge themselves in view of the curved configuration of the head 16 of the rider bars 12.

Furthermore, blinding or pegging is also prevented because particles which contact the curved profile 17 during operation of the screening machine rather than becoming stuck in the space 20 between the domed heads 16 of adjacent rider bars 12 will tend to bounce off the curved profile 17 away from the aperture 22. Thus, the curved profile 17 do not provide ledges or shoulders on which larger particles can become stuck which would tend to blind WO 01/45867 PCT/AU00/01211 7 the aperture 22.

Figure 5 shows a cross-sectional view through an embodiment of the invention which includes the outer peripheral frame and the connection means for connection to a frame of a screening machine.

In the embodiments shown in Figure 5 the screening machine has elongate rails 60 which have upwardly extending arms 61. The panels 10 are configured in the same manner as described with reference to Figures 1 to 4 except that the support members 14 are provided with reinforcing ribs 44 which extend transversely and interconnect the support members 14.

A reinforcing frame 50 formed from metal and material may be embedded in the panel 10 and includes longitudinal rail members 54 which extend within the support members 14 and transverse members 52 which extend within the reinforcing ribs 44.

Peripheral portion 59 of the panel 10 has legs 63 which engage one of the arms 61 of the rails 60. When an elongate retaining member 62 is inserted between adjacent panels the leg 63 is deformed so that it engages beneath the arm 61 to prevent the panel 10 from being separated from the rail 60. Full details of the connection system shown in Figure 5 are disclosed in Australian patent application 96986/98 the contents of which is incorporated into this specification by this reference.

In the preferred embodiment of the invention the panels are moulded from polyurethane material and in particular a polyether or polyester material with durometer 80 to However the panels could be made from metal, wire or other suitable material depending on the intended application.

8 Since modifications within the spirit and scope of the invention may readily be effected by persons skilled within the art, it is to be understood that this invention is not limited to the particular embodiment described by way of example hereinabove.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise", or variations such as "comprises" or "comprising", is used in an inclusive sense, ie. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

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Claims (4)

1. A screen panel for screening of fines or for dewatering of material, comprising; a plurality of rider bars arranged in side by side relationship and defining spaces therebetween for the screening of the fines or for the flow of water between the rider bars; the spaces between adjacent rider bars defining apertures with an aperture size of the apertures being defined by the distance between points on adjacent rider bars which are closest together; a head portion on each rider bar extending upwardly, having regard to the orientation of the screen panel when located on a screening machine, from the plane of the apertures, the head portion being in the form of a dome of substantially semi-circular profile in cross- section perpendicular to the longitudinal axis of the rider bar, so that the space between adjacent head portions and above the apertures tapers outwardly from the apertures; and each rider bar has a lower portion below the plane of the apertures which is defined by side surfaces which taper towards one another so that the space between 25 adjacent lower portions tapers outwardly from a position 9 adjacent the apertures to a lower most extremity of the lower portion of the rider bars. C S.

2. The panel of claim 1 wherein the rider bars are 30 interconnected by a plurality of support members which extend transverse with respect to the rider bars. S.

3. The panel of any one of claims 1 or 2 further including connection means for connecting the screen panels S 35 to a screening machine. S

4. The panel of claim 3 wherein the connection means \uisa\Keep\Speci\ewire CT-AU -01211- en ents.doc 29/12/03 H:\Luisa\Keep\Speci\Melwire PCT-AUOO-01211-Amendments.doc 29/12/03 10 comprises semi-circular recesses and semi-circular bush members on sides of the screen panels so that when two screen panels are placed in side by side relationship the recesses and bushes form an opening through which a pin can be connected so as to couple the screen panels to a screening machine. The panel of claim 3 wherein the connection means comprises deformable legs or rails on the screen panels which are deformed by a retaining member inserted between panels so that the deformable legs or rails engage a frame member of the screening machine to lock the panels to the screening machine. Dated this 29th day of December 2003 MELWIRE PTY LTD By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia 1 e C9 o* *e H:\Luisa\Keep\Speci\Melwire PCT-AU00-01211-Amendments.doc 29/12/03