WO2020245795A1

WO2020245795A1 - Screen tile and modular screening apparatus for dewatering pulp or slurry

Info

Publication number: WO2020245795A1
Application number: PCT/IB2020/055323
Authority: WO
Inventors: Kishor Thekkuveetil
Original assignee: Flsmidth A/S
Priority date: 2019-06-05
Filing date: 2020-06-05
Publication date: 2020-12-10
Also published as: ZA202109842B

Abstract

A modular screening apparatus 300 is comprised of a cylindrical screen basket subframe 200 and a plurality of screen tiles 100 attached to the screen basket subframe 200. The screen basket subframe 200 has a panel structure 208 with a number of apertures 202 extending therethrough. Each aperture 202 of the panel structure 208 receives its own screen tile 100. Each screen tile 100 has a locking feature 128 extending into its respective aperture 202. The locking feature 128 includes an undercut 108 defined by four outer peripheral sides 118 connected by convex blends 116. The undercut 108 may be sized and shaped with the same rounded rectangle aperture shape as the aperture.

Description

SCREEN TILE AND MODULAR SCREENING APPARATUS FOR DEWATERING PULP OR SLURRY

CROSS-REFERENCE TO RELATED APPLICATIONS None.

FIELD OF THE INVENTION This application pertains to the screening arts, and in particular, modular screening apparatus and related methods for dewatering pulp or slurry. Embodiments of the invention may be particularly beneficial and useful as a trommel or as a dewatering device within Carbon-In-Pulp (CIP), Carbon-In- Leach (CIL), and/or Resin-In-Pulp (RIP) systems.

It will become apparent from this disclosure that embodiments of the modular screening apparatus and methods thereof described herein offer various advantages and benefits not yet available with conventional devices.

BACKGROUND OF THE DISCLOSURE

Carbon or resin is traditionally used to recover gold from cyanide leachates. The use of resin in some leach applications results in excessive blinding of traditional screening and dewatering apparatus. Current screen designs typically employ wedge wire screens within apertures of a screen basket subframe. The wedge wire is subject to permanent deformation and blinding.

There has been a long felt need to develop alternative technology which can overcome the shortcomings of conventional dewatering apparatus.

Embodiments of the present invention include an improved screen basket subframe design which incorporates the use of novel, specially-crafted aperture inserts (i.e.,“screen tiles”) that advantageously employ the use of polyurethane or other suitable polymer as an alternative material to metal, in order to provide a modular screening apparatus which is more resistant to pegging and blinding than current state-of-the art solutions.

An exemplary prior art screen apparatus can be seen from U.S. Patent Publication No. 2018/0243797.

OBJECTS OF THE INVENTION

It is, therefore, an object of the invention to provide an improved screening apparatus and method for modularly attaching and removing a screen tile to a screen basket subframe which reduces maintenance time, shut down time, and/or cost.

It is another object of embodiments of the invention to provide a system and method for dewatering pulp or slurry which circumvents the aforementioned problems associated with conventional screening apparatus.

It is a further object of embodiments of the invention to provide a system and method for screening which is robust to wear and provides extended wear life during operation. It is a further object of embodiments of the invention to provide a system and method for screening which utilizes equipment which is quick, cheap, and easy to repair.

These and other objects will be apparent from the appended drawings and description herein.

Although every object is believed to be attained by at least one embodiment of the invention, there is not necessarily any one embodiment of the invention that achieves all of the objects of the invention.

BRIEF SUMMARY OF THE INVENTION

A modular screening apparatus 300 is disclosed. The modular screening apparatus 300 may comprise a cylindrical screen basket subframe 200 and a plurality of screen tiles 100 attached to the screen basket subframe 200. The screen basket subframe 200 may comprise a panel structure 208 with one or more reinforcing ribs 206. The cylindrical panel structure 208 may be characterised in that it comprises a number of apertures 202 therethrough, wherein each aperture 202 comprises four aperture side edges 204 connected to each other by concave blends 210. The side edges 204 and concave blends 210 may define a rounded rectangle aperture shape.

Each aperture 202 of the panel structure 208 may receive its own screen tile 100. Each screen tile 100 may have a locking feature 128 extending into its respective aperture 202 of the panel structure 208. The locking feature 128 may comprise an undercut 108. The undercut 108 may comprise four outer peripheral sides 1 18 connected by convex blends1 16, without limitation. The undercut 108 may being complimentary sized and shaped with the rounded rectangle aperture shape (e.g., of the aperture 200).

Each screen tile 100 may comprise a screening panel 106 provided with at least four screening portions 120. The screening portions 120 may have sized apertures 142 extending therethrough. As exemplified in FIGS. 9-1 1 , the sized apertures 142 may comprise trapezoidal (or triangular) webs 144. The trapezoidal webs 144 may span between parallel and spaced micro support bars 150. The sized apertures 142 may comprise a first smaller width wi adjacent an outer surface 102 of the screening panel 106 and a second larger width W2 adjacent an undersurface 104 of the screening panel 106, without limitation.

Each screen tile 100 may comprise at least one first stiffening member 124 and at least one second stiffening member 126. The at least one first stiffening member 124 and/or at least one second stiffening member 126 may separate the screening portions 120 from each other as illustrated. The at least one first 124 and the at least one second 126 stiffening members may intersect each other at one or more intersections 122.

The screen tiles 100 are preferably constructed by injection molding. Each screen tile 100 may comprise a single, monolithic, unitary piece of injection- molded polymer which is devoid of inserts or bonded layers.

The locking feature 128 may comprise a retention barb defined by a lead-in taper 130 extending between a distal locking feature edge 140 and a proximal locking feature edge 138. The distal locking feature edge 140 may run along a bottom surface 134 of the retention barb as shown in the figures.

The locking feature 128 may further comprise a holding surface 136. The holding surface 136 may form a lower boundary portion of the undercut 108. The lead-in taper 130 may comprise convex blends 132 at each corner of the locking feature 128. The convex blends 132 may closely approximate the size and/or shape of the concave blends 210 of the aperture 202, without limitation.

The screening panel 106 may include an overhanging ledge around its periphery. The overhanging ledge may define an undersurface 1 10. The undersurface 1 10 may define an upper boundary portion of the undercut 108. The undersurface 1 10 may be configured for engaging and resting against the panel structure 208 - such that corners 1 12 of adjacent screen tiles 100 closely approach each other at screen tile junctions 302.

The screening panel 106 may be rectangular in its peripheral shape and may be defined by four sides 114 and four corners 112. The screen basket subframe 200 may be constructed of metal sheeting welded to ribs 206 which are also metallic. The panel structure 208 may be constructed of a single piece of metal sheeting. The sheeting may be rolled and joined together at its ends by a seam 306. The panel structure 208 may also be constructed of more than one piece of metal sheeting bonded together at more than one seam 306, without limitation. For example, two metal sheeting sections may be bonded together to form panel structure 208.

The panel structure 208 may optionally comprise an upper end section 214 which is devoid of screen tiles 100. The panel structure 208 may optionally comprise a lower end section 216 which is devoid of screen tiles 100. The upper end section 214 may have a dimension along an axis 304 of the modular screening apparatus 300 which is greater than a dimension of the of the lower end section 216 along the axis 304. Accordingly, in some embodiments, the upper end section 214 may have a greater area than the lower end section 216. It should be understood that in some embodiments, upper end section 214 and/or lower end section 216 may be omitted or eliminated from the modular screening apparatus 300 design. In this regard, screen tiles 100 may, in some embodiments, extend all the way from the top open edge to the bottom open edge of the panel structure 208 such that substantially all surface area of the modular screening apparatus 300 can be used for dewatering or trommeling.

A screen tile 100 is also disclosed. The screen tile 100 may be configured for insertion into a modular screening apparatus 300, for example, a modular screening apparatus 300 comprising a cylindrical screen basket subframe 200. The screen basket subframe 200 may comprise a panel structure 208 and a number of reinforcing ribs 206, without limitation. The screen tile 100 may be characterised in that it has a locking feature 128 configured to extend into and retain the screen tile 100 within a respective aperture 202 extending through the panel structure 208. The locking feature 128 may comprise an undercut 108. The undercut 108 comprises four outer peripheral sides 1 18 connected by convex blends 1 16. The four outer peripheral sides 1 18 and convex blends 1 16 may define a rounded rectangle aperture shape.

The undercut 108 may be sized and shaped with a rounded rectangle aperture shape which is associated with and/or complimentary to the aperture 202 extending through the panel structure 208.

The screen tile 100 may comprise a screening panel 106. The screening panel 106 may be provided with at least four screening portions 120. The screening portions 120 may have sized apertures 142 extending therethrough. The sized apertures 142 may comprise trapezoidal (or triangular) webs 144. The webs 1 14 may span between micro support bars 150. The sized apertures 142 may comprise a first smaller width (wi), for example, adjacent an outer surface 102 of the screening panel 106. The sized apertures 142 may comprise a second larger width (W2), for example, adjacent an undersurface 104 of the screening panel 106, without limitation. The screen tile 100 may further comprise at least one first stiffening member 124. At least one second stiffening member 126 may also be provided to the screen tile 100. The stiffening members 124, 126 may separate the screening portions 120 from each other. The stiffening members 124, 126 may serve to support screening portions 120. The at least one first 124 and the at least one second 126 stiffening members may intersect at an intersection 122. While not shown, in some embodiments, there may be more than one intersection 122, without limitation.

Upon installation into an aperture 202 of a panel structure 208 of a screen basket subframe 200, the four outer peripheral sides 1 18 of the undercut 108 may be situated in close proximity to four respective aperture side edges 204 of the aperture 202. Upon installation into an aperture 202 of a panel structure 208 of a screen basket subframe 200, convex blends 1 16 of the undercut 108 may be situated in close proximity to four respective concave blends 210 of the aperture 202.

The screen tile 100 may be fabricated in one single, monolithic, unitary piece, for example, by injection molding. The screen tile may be preferably devoid of additional inserts or bonded layers. The locking feature 128 may comprise a retention barb defined by a lead-in taper 130 extending between a distal locking feature edge 140 and a proximal locking feature edge 138. The distal locking feature edge 140 may exist along a bottom surface 134 of the retention barb.

The locking feature 128 may further comprise a holding surface 136. The holding surface 136 may form a lower boundary portion of the undercut 108, without limitation.

The lead-in taper 130 may comprise convex blends 132 at each corner of the locking feature 128. The convex blends 132 may closely approximate the size and/or shape of concave blends 210 associated with the aperture 202 through the panel structure 208 - in which the screen tile 100 is to be inserted.

The screening panel 106 may include an overhanging ledge around its periphery. The overhanging ledge may define a undersurface 1 10. The undersurface 1 10 may define an upper boundary portion of the undercut 108. The undersurface 1 10 may be configured for engaging and resting against a panel structure 208; e.g., such that the corners 1 12 of adjacent screen tiles 100 closely approach each other at screen tile junctions 302 after installation into a screen basket subframe 200.

The screening panel 106 may be rectangular in its peripheral shape. The screening panel 106 may be defined by four sides 1 14 and four corners 1 12, without limitation.

BRIEF SUMMARY OF THE DRAWINGS

To complement the description which is being made, and for the purpose of aiding to better understand the features of the invention, a set of drawings illustrating the new and novel modular screening apparatus, methods of its use and manufacture, and method of attachment and removal of a screen tile to a screen basket subframe is attached to the present specification as an integral part thereof, in which the following has been depicted with an illustrative and non-limiting character.

FIG. 1 illustrates a modular screening apparatus 300 according to one exemplary non-limiting embodiment of the invention.

FIG. 2 illustrates a close-up view of a portion of FIG. 1 , showing a screen tile 100 removed from a screen basket subframe 200. FIGS. 3 and 4 illustrate various views of a screen tile 100, such as the ones shown in FIGS. 1 and 2.

FIG. 5 is a cross-sectional isometric view (viewed from the bottom outside of the modular screening apparatus 300 shown in FIG. 1 ), which illustrates a screen tile 100 being removed from or installed into an aperture 202 of a screen basket subframe 200.

FIG. 6 is a cross-sectional isometric view (viewed from the inside of the modular screening apparatus 300), which illustrates a screen tile 100 installed in an aperture 202 of a screen basket subframe 200.

FIG. 7 is a side profile view of a screen tile 100 shown in FIGS. 1 -6.

FIG. 8 is a close-up view of a top portion of FIG. 7.

FIGS. 9-1 1 show details (e.g., sized openings 142) of screening portions 120 of the screening panel 106, according to some exemplary non-limiting embodiments.

In the following, the invention will be described in more detail with reference to drawings in conjunction with exemplary embodiments.

DETAILED DESCRIPTION

While the present invention has been described herein using exemplary embodiments of a screening apparatus and method of fabrication and use, it should be understood that numerous variations and adaptations of the same will be apparent to those of ordinary skill in the art from the teachings provided herein. The detailed embodiments shown and described in the text and figures should not be construed as limiting in scope; rather, all design features should be considered to be exemplary or suggestive in nature. Accordingly, this invention is only limited by the appended claims.

Moreover, while this subject matter has been disclosed with reference to specific embodiments, it is apparent that other embodiments and variations can be devised by others skilled in the art without departing from the true spirit and scope of the subject matter described herein. The appended claims may include some, but not all of such embodiments and equivalent variations.

Where ranges are disclosed herein, the range may be inclusive of each high and low value listed. All patent publications mentioned herein are hereby incorporated by reference, in their entirety for any and all purposes, as if fully set forth herein.

The inventors have recognized a novel and heretofore unappreciated system and method of dewatering pulp or slurry using a specialized screening apparatus.

Embodiments involve the inventive concept of This involved developing a polyurethane insert to fit inside a substrate basket. The polyurethane screen will be more resistant to pegging and blinding to solve the problem.

A new design was developed consisting of a polyurethane modular screen on a steel or other substrate. The substrate provides the support and is cylindrical or faceted in shape with square or other shaped openings to accept the polyurethane screening panel. The polyurethane screen panel has a clip profile that snaps over the inside and outside to retain it in the substrate opening. Turning now to FIGS. 1 -8, a modular screening apparatus 300 may comprise a screen basket subframe 200 and a plurality of screen tiles 100 secured within respective apertures 202 extending though the screen basket subframe 200.

Each screen tile 100 may have a locking feature 128 comprising a retention barb. The retention barb may be defined by a wider proximal edge 138 of the locking feature 128 extending to a narrower distal edge 140 of the locking feature 128 as shown. A lead-in taper 130 (e.g., an outwardly-flared peripheral surface) may extend between the proximal edge 138 and distal edge 140 as shown, to facilitate alignment with an aperture 202 of the screen basket subframe 200. The ramped surface of the lead-in taper 130 may functionally provide a mechanical advantage and facilitate some radial compression, contraction, deflection, or elastic deformation of locking feature 128 when the screen tile 100 is pressed within aperture 202 against the screen basket subframe 200 towards the central longitudinal axis 304 of the modular screening apparatus 300.

Once fully seated within the aperture 202, a holding surface 136 of the retention barb may engage a radially-inner surface of a panel structure 208 of the screen basket subframe 200, thereby preventing inadvertent removal of the screen tile 100.

As shown, the apertures 202 may comprise a generally rectangular shape having four straight aperture side edges 204 -each being separated by a concave blend 210 such as a fillet, a rounded inside corner, or a smooth transition, without limitation.

A number of ribs 206 may extend longitudinally or axially, as shown, to provide added rigidity to panel structure 208. Intersections 212 between the panel structure 208 and ribs 206 may be welded, without limitation. An upper end section 214 of the screen basket subframe 200 may be optionally provided, which may be generally devoid of screen panels 100 as shown in FIG. 1 . In some non-limiting embodiments, screen panels 100 may extend closer to the bottom of the screen basket subframe 200, forming a lower end section 216 that is narrower than the upper end section, without limitation. However, as previously mentioned, upper and/or lower end sections 214, 216 may be completely omitted/eliminated from the modular screening apparatus 300 design such that screen tiles 100 cover substantially all of the screen basket subframe 200.

While ribs 206 are only shown to extend generally parallel to the central longitudinal axis 304, it is contemplated by the inventors that a number of ribs (not shown) may instead extend circumferentially around the central longitudinal axis 304 at one or more various locations along the central longitudinal axis 304 to support panel structure 208. Moreover, it is envisaged that a combination of longitudinally-extending and circumferentially-extending ribs 206 may be employed. Furthermore, while ribs 206 are shown to extend radially inwardly from the panel structure 208 towards central longitudinal axis 304, it should be understood that the ribs 206 could alternatively extend radially outwardly from the panel structure 208 away from the central longitudinal axis 304. In such latter embodiments, junctions 302 formed between corners 1 12 of screen tiles 100 may be separated by ribs 206.

In cases where the modular screening apparatus 300 is to be used as a trommel, the screen tiles 100 will be reversed and be located inside the panel structure 108 with their outer faces 102 facing radially inwards towards the central longitudinal axis 304, and their undersurfaces 1 10 facing radially outwardly away from the central and against the inside of the panel structure 108. In such trommel embodiments, ribs 206 would be moved from the inside of the screen basket subframe 200 to the outside of the screen basket subframe 200 such that they would extend radially outwardly away from the central longitudinal axis 304 and remain external to the screen basket subframe 200. The ribs 206 in such trommel embodiments can be longitudinal or circumferential as will be described hereinafter. In the embodiment shown (best exemplified in FIGS. 1 and 5), screen tile junctions 302 are formed where screen tile corners 1 12 meet. Similar screen tile junctions 302 would similarly be formed in trommel embodiments where screen tiles 100 are secured from the inside of panel structure 208.

Each screen tile comprises a screening panel 106 having an outer face 102 facing radially outwardly and away from the central longitudinal axis 304 of the modular screening apparatus 300. Underneath the screening panel, 106 facing radially inwardly towards the central longitudinal axis 304, is provided an underside face 104 of the screening panel 106. Extending from the underside face 104 may be one or more stiffening or reinforcing members. For example, as shown, at least one first stiffening member 124 may be provided. In addition to the at least one first stiffening member 124, at least one second stiffening member 126 may be provided to the panel 106.

As shown, the at least one first stiffening member 124 may extend substantially orthogonally (or within 0-45 degrees) with respect to ribs 206 and/or central longitudinal axis 304, without limitation. As shown, the at least one second stiffening member 126 may extend substantially parallel to (or within 45-90 degrees from) ribs 206 and/or central longitudinal axis 304, without limitation. As shown, the at least one first stiffening member 124 may be generally orthogonal with the at least one second stiffening member 126, without limitation. An intersection 122 may be formed where the at least one first stiffening member 124 and the at least one second stiffening member 126 meet. Panel structure 208 may be comprised of one or more panels positioned adjacent each other and bonded to ribs 206, or, panel structure 208 may comprise a single sheet rolled out with edges bonded together at a seam 306 as shown in FIG. 1 , without limitation. The screening panel 106 may comprise a number of sides 1 14, which may, as shown, be flat. The sides 1 14, however, may not be flat or straight as illustrated in the drawings, and may instead be rounded or curved for example, without limitation. Corners 1 12 of each screening panel 106 may be sharp as shown, or may comprise a convex blend, chamfer, rounded outside corner, or smooth transition between sides 1 14, without limitation.

Along an outer perimeter of the screen tile 100 is an undercut 108, such as a circumferential groove extending around the screen tile 100 adjacent the screening panel 106. An undersurface 1 10 of an overhanging ledge of the screening panel 106 may make contact with the panel structure 208 when the screen tile 100 is seated against the screen basket subframe 200.

The undercut 108 may be formed between the undersurface 1 10 and a holding surface 136 of the retention barb. The deepest portion of the undercut 108 may comprise one or more outer peripheral sides 118 which may be connected via convex blends 116. Each of the convex blends 1 16 of the undercut 108 may comprise, for instance, a chamfer, a rounded outside corner, or a smooth transition as shown, without limitation.

It is preferred that the dimensions of the undercut 108 (e.g., the distances between opposing outer peripheral sides 1 18, and/or the shape and configuration of convex blends 1 16) are such that they can be received in apertures 202. The deepest surfaces of the undercut 108 may fit closely and rest adjacent to surfaces 204, 210 of the aperture 202 when a screen tile 100 is installed within the aperture 202. As shown, aperture 202 may be sized slightly larger than undercut 108, and the shape of the undercut 108 may complement or closely resemble the shape of the aperture 202. It is preferred that corners of the aperture not be sharp as indicated by reference numeral 210. Between the one or more first 124 and/or second 126 stiffening members may be screening portions 120 of the screening panel 106 which have sized openings 142 extending therethrough for separating fluids from solids. These sized openings 142 (shown in FIGS. 9-1 1) may help dewater pulp or slurry by allowing a liquid fraction to move radially inwardly through screening panel 106, through the aperture 202, and into the modular screening apparatus 300, towards the central longitudinal axis 304. Solids (e.g., ore particles, pulp, carbon, or resin) may be stopped at outer surface 102 of the screening panel 106 and kept from passing through the screen tile 100 towards the underside face 104 and into the modular screening apparatus 300.

The locking feature 128 may comprise a continuous, uninterrupted retention barb as shown, and may be provided with a bottom surface 134 which protrudes through aperture 202 and is generally parallel with panel structure 208, without limitation. Moreover, convex blends 132 (e.g., chamfers, rounded outside corners, smooth transitions, or the like) may be provided at select portions of Lead-in taper 130, as shown. Alternatively, while not shown, the locking feature 128 may comprise a number of disruptions so as to form a discontinuous, interrupted retention barb to increase flexibility and/or elastic deformation of locking feature 128 during insertion into aperture 202. For example, a disruption in the form of a single slit (not shown) may enable the retention barb to flex inwardly more easily. As another example, a plurality of slits may extend through the locking feature 128 to form bifurcated flexible legs which are cantilevered from screening panel 106, without limitation. Other grommet features, sealing means, and fastening means known in the art may be employed between screen tiles 100 and apertures 202, without limitation.

It should be appreciated that the modular screening apparatus 300 shown and described herein may be completely inverted (i.e., turned inside out), wherein screen tiles 100 may be installed within the subframe 208 by pressing the tiles 100 into the apertures 202 in a direction radially outwardly with respect to the central longitudinal axis 304. In this regard, tiles 100 can alternatively be inserted into or removed from apertures 202 from the inside of the screen basket subframe 200, rather than from the outside of the screen basket subframe 200 as illustrated. In such inverted embodiments, the sized openings 142 extending through each screening panel 106 may help dewater pulp or slurry within the modular screening apparatus 300 by allowing a liquid fraction to move radially outwardly through screening panel 106, through the aperture 202, and exit the modular screening apparatus 300, away from the central longitudinal axis 304, leaving solids (e.g., ore particles, pulp, carbon, or resin) contained within the modular screening apparatus 300, without limitation.

Sized openings 142 extending through screening portions 120 of the screening panel 106 may be provided in any pattern, style, or organization. They may have varying cross-sectional area and/or varying cross-sectional shape throughout their depth through the screening panel 106, without limitation.

FIGS. 9 - 1 1 exemplify one non-limiting example of sized openings 142 which may be employed to screening portions 120 within screening panel 106. As shown, sized openings 142 may be provided as slits through the screening panel 106 at screening portions 120. A series of trapezoidal webs 144 extending between micro support bars 150 may define the sized openings 142. The trapezoidal webs 144 may comprise a trapezoidal cross-section as shown, or they may alternatively be triangular in cross-section (not shown), without limitation. Trapezoidal webs 144 may each comprise a first tapering side 146 and a second tapering side 148. By virtue of the first 146 and second 148 tapering sides, the sized openings 142 may comprise a first smaller width wi adjacent the outer face 102 of the screening panel 106, and a second larger width W2 adjacent the underside face 104 of the screening panel 106. The micro support bars 150 may span between stiffening members 124, 126 and/or between a stiffening member 124, 126 and locking feature 128 in any conceivable fashion. The micro support bars 150 may, as shown, be shallower in depth, and thinner in thickness than stiffening members 124, 126, without limitation.

It should be understood that where a single feature, apparatus, component, or device is mentioned herein, a plurality of the same feature, apparatus, component, or device may be employed. Accordingly, where used herein, the term“a” preceding a noun may, in most practical instances, be replaced with“at least one of or“a plurality’, without limitation. Although the invention has been described in terms of particular embodiments and applications, it should be appreciated that one of ordinary skill in the art, in light of this teaching, can generate additional embodiments and modifications without departing from the spirit of or exceeding the scope of the claimed invention.

LIST OF ENUMERATED IDENTIFIERS IN THE DRAWINGS

100 Screen tile

102 Outer face of screening panel (facing radially outwardly)

104 Underside face of screening panel (facing radially inwardly)

106 Screening panel

108 Undercut (e.g., circumferential groove)

1 10 Undersurface of overhanging ledge

1 12 Corner of screening panel

1 14 Side of screening panel

1 16 Convex blend (e.g., chamfer, rounded outside corner, smooth transition)

1 18 Outer peripheral side of undercut

120 Portion(s)/Area(s) of screening panel having sized apertures extending therethrough

122 Intersection of stiffening members

124 At least one first stiffening member (e.g., extending substantially orthogonally or within 0-45 degrees with respect to ribs and/or central longitudinal axis)

126 At least one second stiffening member (e.g., extending substantially parallel to or within 45-90 degrees from ribs and/or central longitudinal axis)

128 Locking feature comprising a retention barb

130 Lead-in taper (e.g., outwardly-flared peripheral surface)

132 Convex blend (e.g., chamfer, rounded outside corner, smooth transition)

134 Bottom surface

136 Holding surface of retention barb

138 Proximal locking feature edge

140 Distal locking feature edge

142 Sized openings (e.g., slits)

144 T rapezoidal web

146 First tapering side

148 Second tapering side 150 Micro support bar

200 Screen basket subframe

202 Aperture

204 Aperture side edges

206 Rib (e.g., longitudinally or axially-extending)

208 Panel structure

210 Concave blend (e.g., fillet, rounded inside corner, smooth transition)

212 Intersection between panel structure and rib

214 Upper end section of screen basket subframe

216 Lower end section of screen basket subframe

300 Modular screening apparatus

302 Screen tile junctions

304 Central longitudinal axis of modular screening apparatus

306 Seam

wi First smaller width

W2 Second larger width

Claims

1 . A modular screening apparatus (300) comprising a cylindrical screen basket subframe (200) and a plurality of screen tiles (100) attached thereto, the screen basket subframe (200) comprising a panel structure (208) and reinforcing ribs (206), CHARACTERISED IN THAT the cylindrical panel structure (208) comprises a number of apertures (202) therethrough, each aperture (202) comprising four aperture side edges (204) connected to each other by concave blends (210) defining a rounded rectangle aperture shape; each aperture (202) of the panel structure (208) receiving its own screen tile (100), each screen tile (100) having a locking feature (128) extending into its respective aperture (202), the locking feature (128) comprising an undercut (108) comprising four outer peripheral sides (1 18) connected by convex blends (1 16), the undercut (108) being complimentary sized and shaped with the rounded rectangle aperture shape;

wherein each screen tile (100) comprises a screening panel (106) provided with at least four screening portions (120); the screening portions (120) having sized apertures (142) extending therethrough, the sized apertures (142) comprising trapezoidal webs (144) spanning between micro support bars (150), wherein the sized apertures (142) comprise a first smaller width (wi) adjacent an outer surface (102) of the screening panel (106) and a second larger width (W2) adjacent an undersurface (104) of the screening panel (106);

each screen tile (100) further comprising at least one first stiffening member (124) and at least one second stiffening member (126) separating the screening portions (120) from each other, the at least one first (124) and the at least one second (126) stiffening members intersecting at an intersection (122).

2. The modular screening apparatus (300) according to claim 1 , wherein the screen tiles (100) are constructed by injection molding and each screen tile (100) comprises a single, monolithic, unitary piece of injection-molded polymer devoid of inserts or bonded layers.

3. The modular screening apparatus (300) according to claim 1 or 2, wherein the locking feature (128) comprises a retention barb defined by a lead- in taper (130) extending between a distal locking feature edge (140) along a bottom surface (134) of the retention barb, and a proximal locking feature edge (138).

4. The modular screening apparatus (300) according to any one of the preceding claims, wherein the locking feature (128) further comprises a holding surface (136) forming a lower boundary portion of the undercut (108).

5. The modular screening apparatus (300) according to any one of the preceding claims, wherein the lead-in taper (130) comprises convex blends (132) at each corner of the locking feature (128), the convex blends (132) closely approximating the size and/or shape of the concave blends (210) of the aperture (202).

6. The modular screening apparatus (300) according to any one of the preceding claims, wherein the screening panel (106) includes an overhanging ledge around its periphery that defines an undersurface (1 10), the undersurface (1 10) defining an upper boundary portion of undercut (108); the undersurface (1 10) being configured for engaging and resting against the panel structure (208) such that corners (1 12) of adjacent screen tiles (100) closely approach each other at screen tile junctions (302).

7. The modular screening apparatus (300) according to any one of the preceding claims, wherein the screening panel (106) is rectangular in its peripheral shape and is defined by four sides (1 14) and four corners (1 12).

8. The modular screening apparatus (300) according to any one of the preceding claims, wherein the screen basket subframe (200) is constructed of metal sheeting welded to ribs (206) which are also metallic.

9. The modular screening apparatus (300) according to any one of the preceding claims, wherein the panel structure (208) is constructed of a single piece of metal sheeting rolled and joined together at its ends by a seam (306).

10. The modular screening apparatus (300) according to any one of the preceding claims, wherein the panel structure (208) comprises an upper end section (214) which is devoid of screen tiles (100) and a lower end section (216) which is devoid of screen tiles (100), and wherein the upper end section (214) has a dimension along an axis (304) of the modular screening apparatus (300) which is greater than a dimension of the of the lower end section (216) along the axis (304).

1 1. A screen tile (100) for insertion into a modular screening apparatus (300) comprising a cylindrical screen basket subframe (200); the screen basket subframe (200) comprising a panel structure (208) and reinforcing ribs (206), CHARACTERISED IN THAT the screen tile (100) has a locking feature (128) configured to extend into and retain the screen tile (100) within a respective aperture (202) extending through the panel structure (208), the locking feature (128) comprising an undercut (108); the undercut (108) comprising four outer peripheral sides (1 18) connected by convex blends (1 16) defining a rounded rectangle aperture shape, the undercut (108) being complimentary sized and shaped with a rounded rectangle aperture shape associated with the aperture (202) extending through the panel structure (208);

wherein the screen tile (100) comprises a screening panel (106) provided with at least four screening portions (120); the screening portions (120) having sized apertures (142) extending therethrough, the sized apertures (142) comprising trapezoidal webs (144) spanning between micro support bars (150), wherein the sized apertures (142) comprise a first smaller width (wi) adjacent an outer surface (102) of the screening panel (106) and a second larger width (W2) adjacent an undersurface (104) of the screening panel (106);

the screen tile (100) further comprising at least one first stiffening member (124) and at least one second stiffening member (126) separating the screening portions (120) from each other, the at least one first (124) and the at least one second (126) stiffening members intersecting at an intersection (122).

12. The screen tile (100) as described in claim 1 1 , wherein upon installation into an aperture (202) of a panel structure (208) of a screen basket subframe (200), the four outer peripheral sides (1 18) of the undercut (108) are situated in close proximity to four respective aperture side edges (204) of the aperture (202); and wherein upon installation into an aperture (202) of a panel structure (208) of a screen basket subframe (200) the convex blends (1 16) of the undercut (108) are situated in close proximity to four respective concave blends (210) of the aperture (202).

13. The screen tile (100) according to claim 1 1 or 12, wherein the screen tile (100) is fabricated in one single, monolithic, unitary piece by injection molding and is devoid of additional inserts or bonded layers.

14. The screen tile (100) according to any one of claims 1 1 -13, wherein the locking feature (128) comprises a retention barb defined by a lead-in taper (130) extending between a distal locking feature edge (140) along a bottom surface (134) of the retention barb, and a proximal locking feature edge (138).

15. The screen tile (100) according to any one of claims 1 1 -14, wherein the locking feature (128) further comprises a holding surface (136) forming a lower boundary portion of the undercut (108).

16. The screen tile (100) according to any one of claims 1 1 -15, wherein the lead-in taper (130) comprises convex blends (132) at each corner of the locking feature (128), the convex blends (132) closely approximating the size and/or shape of concave blends (210) associated with the aperture (202) through the panel structure (208).

17. The screen tile (100) according to any one of claims 1 1 -16, wherein the screening panel (106) includes an overhanging ledge around its periphery that defines a undersurface (1 10), the undersurface (1 10) defining an upper boundary portion of undercut (108); the undersurface (1 10) being configured for engaging and resting against a panel structure (208) such that corners (1 12) of adjacent screen tiles (100) closely approach each other at screen tile junctions (302) after installation into a screen basket subframe (200).

18. The screen tile (100) according to any one of claims 1 1 -17, wherein the screening panel (106) is rectangular in its peripheral shape and is defined by four sides (1 14) and four corners (1 12).