Sedimentation centrifuge with laminates for improved particle recovery

Abstract

A screw assembly for a centrifuge comprises at least one laminate pack assembly (11) located near a first end of the screw device. The laminate pack assembly (11) may have a plurality of laminates and be disposed upstream of a weir (31) or waste liquid outlet orifice (4) that allows liquid components (33) of the feed slurry to be discharged from the centrifuge. The laminates are preferably configured and arranged to shift fine solids (35) entrained in the liquid component (33) radially outward, or at least impede them from moving radially inward before the liquid component (33) passes through the laminates and through the weir (31) or the waste liquid outlet orifice (4), thereby producing a discharged clear liquid (36) that is substantially free of fine solids (35).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] none Technical Field

[0003] Embodiments of the present invention relate to novel assemblies for centrifuges, particularly assemblies for horizontal screen bowl or solid bowl type decanter centrifuges. These embodiments are particularly useful for improving performance, efficiency and / or particle recovery when used in industrial dewatering processes. The novel assemblies include one or more unique lamella structures disposed near the liquid outlet to inhibit particle discharge with the wastewater. These structures can be designed to be modular, for example, provided in the form of replaceable / maintainable lamella pack cartridges, but are not limited thereto. Background Art

[0004] A centrifuge (also known as a settler or screen bowl / solid bowl centrifuge) is an industrial device designed to receive a slurry (such as sludge or mud) containing solid particles and liquid. It is generally configured to achieve solid-liquid separation through centrifugal action and is suitable for use in minerals, coal, chemicals, food processing, paper mills, drilling recovery and sewage treatment. The purpose of a centrifuge is to achieve the cleanest separation between solids and liquids while maximizing output and minimizing power consumption.

[0005] Particularly in mineral processing applications, the particles in the solid component of the feed slurry may include fine solid materials, such as, but not limited to, ore (e.g., coal). The feed slurry enters axially into a horizontally arranged central feed pipe. The central feed pipe delivers the feed slurry to the inner cavity of a concentrically arranged screw device surrounding the pipe. The screw device rotates with the outer cylindrical bowl body. Typically, the rotation speed (RPM) needs to be slightly faster or slightly slower than the bowl body in order for the solids to be moved. The rotation of the bowl body produces a gravitational G force on the feed slurry, while the rotation of the screw device (scroll) causes the solids to move axially along the inner surface of the bowl body. The screw device may also be called a spiral blade conveyor or screw conveyor, and typically includes one or more spiral blades extending outwardly therefrom, as shown in the accompanying figure. The diameter of the bowl body is slightly larger than the screw device and typically has a similar tapered profile.

[0006] The continuous inflow of feed slurry combined with the centrifugal force generated by the rotation of the bowl body forces the slurry to move away from the inner cavity of the screw device and radially outward through the opening of the screw device to the inner surface area of ​​the bowl body. When the slurry is fully accumulated in the inner surface area of ​​the bowl body, it continues to distribute over the entire inner surface of the bowl body. Subsequently, due to the effect of gravity and the relative density difference between the liquid and solid components, the liquid and solid phases of the slurry begin to separate in the radial direction (relative to the central axis of rotation).

[0007] The lighter liquid components migrate radially inward from the inner surface of the bowl toward the central axis of rotation (i.e., toward the screw device), while the heavier / denser solid components migrate radially outward from the central axis of rotation (i.e., away from the screw device) until an equilibrium operating state is reached. The stratification process causes the liquid components to settle radially inward of the denser solid particles, thereby forming a solid-liquid interface between the solid and liquid layers. The radial distance between the solid-liquid interface and the central axis of rotation can be optimized or stabilized by adjusting operating parameters such as feed rate, RPM, outlet orifice weir position, and slurry composition (such as solid content percentage). The solid-liquid interface may be located in the flank area of ​​the spiral blade.

[0008] The centrifuge operates by allowing the formed inner liquid layer to migrate axially towards the outlet openings of one or more end cover plates at one end of the bowl, while simultaneously conveying the underlying solids bed axially to the solids discharge outlet at the other end of the bowl in a countercurrent manner. The provision of spiral blades on the periphery of the spiral device helps to convey the denser / heavier solids axially to the solids discharge outlet.

[0009] In this process, particles in the liquid layer that have not fully migrated outward may be entrained in the liquid component discharged from the waste liquid outlet hole. This will affect the clarity of the liquid, increase the turbidity of the liquid component, and cause solid product loss (i.e., low particle recovery rate).

[0010] As a result, some in the industry choose to use solid bowl centrifuges rather than screen bowl centrifuges for low particulate content slurries. Others choose to reduce the area of ​​the outlet hole, change the shape of the outlet hole (or reposition the outlet hole radially inward) to make it more difficult for particulates to exit with the liquid component. Still others consider restricting or blocking the outlet hole of the screen bowl to further reduce the appearance of particulates in the liquid waste stream, while others use adjustable liquid weir systems to "skim" the liquid layer at different radial distances. Unfortunately, the above workarounds usually further reduce the output or overall efficiency of the centrifuge.

[0011] The operation of the screen bowl and the solid bowl is very similar. Some common operations of the two are: i) the feed slurry enters through the feed tube and exits through the holes in the screw; ii) solids settle to the outside of the rotating bowl under the action of gravity, and the solids are moved by the screw; iii) the screen bowl and the solid bowl are similar in shape, usually including flat and inclined sections for solids to pass to the outlet of the centrifuge (i.e., the solids discharge outlet); iv) water is discharged through the weir on the end wall; v) the collected solids are scraped from the water and discharged to the outlet of the centrifuge (i.e., the solids discharge outlet); vi) a certain small RPM difference between the screw and the bowl is usually required to allow for relative movement of solids along the bowl; vii) the speed of the screw is generally 20RPM to 50RPM different from that of the bowl; and viii) a slower speed difference can reduce wear and torque.

[0012] Differences between screen bowls and solid bowls include: i) screen bowls may have screen sections (pushed by scrapers) to allow further drainage through the solids bed; ii) screen bowl feeds are typically coarser than conventional solid bowl feeds; iii) solid bowls typically generate higher centrifugal forces during operation than screen bowls; iv) solid bowls typically exhibit a finer range of solids and may require the use of flocculants.

[0013] Although prior art centrifuges have achieved some success in the solid-liquid separation industry, it is still desirable to provide an improved spiral assembly that can achieve more efficient solid-liquid separation, reduce particulate entrainment in the liquid waste stream, and increase particulate recovery by capturing the particulates in the solid discharge stream. Summary of the invention

[0014] Purpose of the Invention

[0015] According to some embodiments, it is desirable to provide a horizontal centrifuge configured to perform a solid-liquid separation process more efficiently, but is not limited thereto.

[0016] According to some embodiments, it is desirable to provide an improved horizontal centrifuge screw assembly that performs better than conventional counterparts, but is not limited thereto.

[0017] According to some embodiments, it is desirable to provide an improved horizontal centrifuge outlet orifice design that provides cleaner separation between solids and liquids, inhibits entrainment of particles in liquid waste streams, and improves particle recovery without significantly increasing power consumption or reducing throughput, but is not limited thereto.

[0018] According to some embodiments, it is desirable to provide an improved horizontal centrifuge outlet port design that prevents particles smaller than 45 microns from being discharged with the liquid waste stream (e.g., configurable to limit the passage of particles of 20-25 microns or smaller without affecting yield or centrifuge performance), but is not limited thereto.

[0019] According to some embodiments, it is desirable to provide a novel layer plate structure near one or more outlet holes to introduce one or more tortuous resistance paths to prevent particles from flowing out with the liquid, but is not limited thereto.

[0020] According to some embodiments, it is desirable to provide means for removing, replacing and / or maintaining novel ply structures, but is not limited thereto.

[0021] According to some embodiments, it is desirable to provide a novel deck structure that can be suitable for use in screen bowl and / or full bowl centrifuges, but is not limited thereto.

[0022] These and other objects of the present invention will be apparent from the accompanying drawings and the description herein.Although each object of the present invention is believed to be achieved by at least one embodiment, there is not necessarily a single embodiment that can achieve all objects of the present invention.

[0023] Brief description of the invention

[0024] A spiral assembly (1) of a centrifuge (100) is disclosed. The spiral assembly (1) may include a spiral device (2) configured to be placed in a bowl (30). The spiral assembly (1) may have a first end (9) near a waste liquid discharge port and a second end (8) near a solid discharge port. The spiral device (2) may have an inner cavity (39). The inner cavity (39) may be configured to receive a feed slurry from a pipe (5) having a feed opening (10). The inner cavity (39) may be defined by a tubular spiral wall (4). The tubular spiral wall (4) may have a plurality of slurry openings (14) penetrating therethrough. At least one spiral blade (6, 7, 15) may be disposed on an outer portion of the spiral device (2) (e.g., disposed on the tubular spiral wall (4), but not limited thereto). The spiral device (2) is characterized in that it includes at least one layer plate pack assembly (11). At least one layer plate pack assembly (11) may be disposed near the first end (9) of the spiral device (2). The ply pack assembly (11) may comprise a plurality of plies (11d).The ply pack assembly (11) may be disposed upstream of a weir (31) or waste outlet port (4) that allows the liquid component (33) of the feed slurry to be discharged from the centrifuge (100).

[0025] The plurality of layers (11d) may be configured and / or arranged so as to move fine solids (35) entrained in the liquid component (33) radially outward, or at least prevent the liquid component (33) from migrating radially inward as it passes between the layers (11d) before the liquid component (33) passes through the weir (31) or the waste liquid outlet port (4). This is done to produce a discharged clarified liquid (36) substantially free of fine solids (35), but is not limited thereto.

[0026] According to some embodiments, at least one ply pack assembly (11) may be received in an external cutout (29), a waste outlet port (4), or a ply pack receiving portion (29) disposed on a portion of the backing plate (27).

[0027] According to some embodiments, at least one of the ply pack assemblies (11) may include a mounting flange (11a). The mounting flange (11a) may be configured to be fastened to a backing plate (27) or an end cap plate (3).

[0028] According to some embodiments, at least one ply pack assembly (11) may include an end surface (11e). The ply (11d) may be captured between the end surface (11e) and the mounting flange (11a), but is not limited thereto.

[0029] According to some embodiments, the end surface (11e) and the mounting flange (11a) may be provided with slits or notches (11h). These slits or notches (11h) may be configured to receive and / or support the tab portion (11i) of the ply (11d) and / or facilitate the manufacture of the ply pack assembly (11), but are not limited thereto.

[0030] According to some embodiments, the end face (11e) of at least one ply pack assembly (11) may abut a weir plate (23). The weir plate (23) may comprise a weir (31) or a back plate (27).

[0031] According to some embodiments, the weir plate (23) may be adjacent to the end cover plate (3) containing the waste liquid outlet hole (4).

[0032] According to some embodiments, when the centrifuge (100) is in operation, the inlet side (11f) of at least one layer plate pack assembly (11) may be located radially inside the solid-liquid interface (36) relative to the rotation center axis (21). The inlet side (11f) of at least one layer plate pack assembly (11) may be located radially outside the outlet side (11g) of at least one layer plate pack assembly (11).

[0033] According to some embodiments, the spiral assembly may include a plurality of ply pack assemblies (11), wherein an annular shield (26) may separate and / or span between the inlet side (11f) of each of the plurality of ply pack assemblies (11). The annular shield (26) may be configured to bias the liquid component (33) toward the inlet side (11f) of each of the plurality of ply pack assemblies (11).

[0034] According to some embodiments, at least one ply pack assembly (11) may be removable and / or replaceable for cleaning or maintenance.

[0035] According to some embodiments, at least one ply pack assembly (11) may be removed and / or replaced only from the first end (9) of the spiral assembly (1) for cleaning or maintenance.

[0036] According to some embodiments, the spiral assembly may further include and / or be disposed within a bowl (30). The bowl (30) may be selected from a screen bowl or a solid bowl. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] To supplement the description made and help better understand the features of the present invention, a set of drawings are attached to illustrate preferred but non-limiting embodiments of the present invention, which include the improved spiral assembly 1 and its components used in a centrifuge, wherein the following is exemplary and non-limiting in nature. It should be understood that similar reference numerals are used in the drawings.

[0038] Figure 1A side perspective view of an exemplary screw assembly 1 including a screw device 2 and a ply pack assembly 11 is shown according to an embodiment.

[0039] Figure 2 Shows Figure 1 Partial cross-sectional view of the spiral component 1.

[0040] Figure 3 Shows Figure 1 An enlarged view of the waste discharge end of the spiral assembly 1 is shown with the end cover plate 3 removed from the waste discharge end 9 for clarity.

[0041] Figure 4 for Figure 3 Another view of the present invention, in which the weir plate 23 has been removed from the waste liquid discharge end 9 for clear display.

[0042] Figure 5 for Figure 4 A magnified view of a portion of the

[0043] Figure 6 for Figure 5 Another view of the invention, wherein the side guard 25 has been removed for clarity.

[0044] Figures 6 to 14 It is shown how one or more ply pack assemblies 11 may be assembled into a spiral assembly 1 in a "post-installation" configuration.

[0045] Figure 7 for Figure 6 Another view of the invention in which the back plate 27 has been removed for a clearer understanding.

[0046] Figure 8 for Figure 7 A front cross-sectional view of the upper left middle component (i.e., the layer package component 11).

[0047] Fig. 9 Shows Figure 7 Side view of the middle board package assembly 11, the cross-sectional plane and Figure 7 The section plane is vertical.

[0048] Fig.10 Shows Figure 7 Another perspective view of the ply package assembly 11 is shown in the upper left center.

[0049] Fig.11 Shows Figure 1 Another cross-sectional view of the spiral assembly 1 is shown.

[0050] Fig.12 for Fig.11 Magnified view of the indicated portion.

[0051] Fig.13 for Fig.12 Magnified view of the indicated portion.

[0052] Fig.14 Shows Fig.12 Another view of the indicated portion.

[0053] Fig.15 Shows the contents Figures 1 to 14 Photograph of a centrifuge with spiral assembly 1 shown.

[0054] Figures 16 to 18 It is shown how one or more ply pack assemblies 11 may be assembled into a screw assembly in a "front mount" configuration.

[0055] Fig.16 Another embodiment of a ply pack assembly 11 that is insertable and removable from the first (discharge) end 9 of the spiral assembly 1 is shown.

[0056] Fig.17 Shows which Fig.16 A cross-sectional view of the spiral assembly 1 of the ply pack assembly 11 is shown.

[0057] Fig.18 Shows which Fig.16 A partial end perspective view of the spiral assembly 1 of the ply pack assembly 11 is shown, and the removal direction of the ply pack assembly 11 is indicated by an arrow.

[0058] Fig.19 Shows that it can contain Fig.18 The sieve bowl of the spiral assembly 1 shown can be used Fig.15 In the centrifuge (100) shown.

[0059] Fig. 20 Shows that it can contain Fig.18 The solid bowl of the spiral assembly 1 is shown and can be used Fig.15 In the centrifuge (100) shown.

[0060] The present invention will be described in more detail below with reference to the accompanying drawings and exemplary embodiments. DETAILED DESCRIPTION

[0061] A novel spiral assembly 1 of a centrifuge 100 is disclosed. Figure 1 and Figure 2 As shown, the spiral assembly 1 includes a spiral structure 2 having a first end 9 for the liquid waste component of the feed slurry to flow out, and a second end 8 opposite to the first end 9 for the solid component of the feed slurry to be discharged. The spiral assembly 1 can rotate about a rotation center axis 21 located between the first end 9 and the second end 8. The spiral assembly 1 is designed to be installed in a centrifuge 100, such as Fig.15 shown.

[0062] Feed slurry enters through the slurry feed opening 10 and is transferred to the inner cavity 39 through the conduit 5. One or more inner baffles 22 may be disposed in the inner cavity 39 to stabilize the slurry in the inner cavity 39. Where used, the inner baffles 22 may include a slurry opening 40, such as a central hole or orifice, as shown. Through centrifugal action, the slurry in the inner cavity 39 may be radially outwardly discharged from the inner cavity 39 through the one or more slurry openings 14. The centrifuged slurry 32 moves radially outward to the outer bowl 30 surrounding the auger 2.

[0063] like Fig.13 and Fig.14 As shown, the centrifuged slurry 32 begins to separate into a solid layer 37 (closer to the bowl 30) and a liquid layer 33 (further away from the bowl 30). A solid-liquid interface 38 can be loosely defined between the solid layer 37 and the liquid layer 33, although the interface may not be a clear boundary and can be defined as an intermediate layer or layer therebetween.

[0064] The screw assembly 1 may include an end cap plate 3 adjacent to the first end 9. The end cap plate 3 may include one or more (preferably a plurality) waste outlet holes 4. Through these waste outlet holes 4, the clarified liquid component of the feed slurry is discharged from the centrifuge 100 by discharging from the chamber between the screw device 2 and the bowl body 30.

[0065] The outer (conical) spiral / ribbon blade 6 can be disposed on or around the spiral wall 24. As shown, the spiral wall 24 can define the boundaries of the inner cavity 39 and can include one or more slurry openings 14. The spiral / ribbon blade 6 can be disposed, for example, in the middle 17 section of the spiral assembly 1. The conical spiral / ribbon blade 6 can extend from near the first end 9 all the way around the spiral wall 24 to the second end 8, spanning the first section 16, the middle section 17 and the second section 18. In the figure, a portion of the spiral / ribbon blade 6 is tapered in the middle section 17, for example, its outer diameter gradually decreases toward the second end 8 and / or the second section 18, but is not limited to this. In addition, as shown, a portion of the spiral / ribbon blade 6 can have a floating spiral / ribbon blade 7 in the first section 16 or near the first end 9, but is not limited to this.

[0066] If a floating spiral / ribbon blade 7 is used, it can be supported by one or more standoffs 12, such as one or more blades extending radially outward from the spiral wall 24. The support 12 can extend along the spiral wall 24 in a direction parallel to the central axis of rotation 21, as shown. The one or more supports 12 may include one or more raised seats 13 for supporting the radial inner surface or contact point of the floating spiral / ribbon blade 7. The one or more raised seats 13 can be configured as "cutouts" in the generally planar support 12, as shown. Alternatively, although not shown in the figure, the support 12 can also be composed of a separate independent support element or a flange extending from the spiral wall 24 at different independent positions along the spiral wall 24, without being limited to this.

[0067] Due to the design and configuration of the floating spiral / ribbon blade 7, the support member 12 and the raised seat 13 for supporting the floating spiral / ribbon blade 7, a plurality of open axial waste liquid channels 19 are formed between the spiral wall 24 and the floating spiral / ribbon blade 7 in the first section 16 near the first end 9. These open axial waste liquid channels 19 help to reduce the turbulence of the countercurrent layers 33, 37 when the material moves axially between the bowl 30 and the screw device 2. In particular, the open axial waste liquid channels 19 defined by the floating spiral / ribbon blade 7 can make it easier for the liquid component 33 of the centrifuged slurry 32 to migrate axially to the first end 9 and pass through the waste liquid outlet hole 4 without disturbance caused by turbulence or mechanical structure (which can cause entrainment of fine solids in the discharged clarified liquid 36 or increase the turbidity of the discharged clarified liquid 36).

[0068] like Figure 1 As most clearly shown in FIG. 1 , the floating spiral / ribbon blade 7 portion of the spiral / ribbon blade 6 can transition to the spiral wall 24 in the central region (e.g., midsection 17) of the spiral assembly 2, without limitation. The portion of the spiral / ribbon blade 6 of the spiral assembly 1 toward the second end 8 can include a discharge spiral / ribbon blade 15, which can be tapered or not.

[0069] It should be understood that although only a single spiral / ribbon blade 6 is shown in the figure, multiple spiral / ribbon blades 6 can also be provided, which can be nested or staggered with each other to form a multi-helix spiral device 2, but it is not limited to this.

[0070] Figure 3The first end 9 of the spiral assembly 1 is shown without the end cap plate 3. As shown, a weir plate 23 can be provided below the end cap plate 3. The weir plate 23 can include a plurality of circumferentially spaced openings, each of which defines a portion of the waste outlet aperture 4 and is aligned with an opening through the end cap plate 3. The opening extending through the weir plate 23 can have a radially outer edge defining a weir 31. Behind the weir plate 23 can be an annular shroud extending generally vertically and / or axially from the weir plate 23. A ply pack assembly 11 (e.g., a ply "box") can be provided behind the weir plate 23, proximate one, some or each waste outlet aperture 4, but is not limited thereto.

[0071] Reference Figure 4 and Figure 5 , the weir plate 23 is removed for a clearer view, and the plurality of ply pack assemblies 11 can be seen between the side baffles 25 behind the weir plate 23. For example, the side baffles 25 can extend radially inwardly from the annular shroud 26 and form an integral part thereof. The back plate 27 can be disposed behind the side baffles and can extend radially inwardly from the annular shroud 26. The back plate 27 can form an integral part of the annular shroud 26, but is not limited thereto.

[0072] Figure 6 Shown Figure 4 and Figure 5 , where the annular cover 26 and the side guard 25 have been removed for a clearer understanding. It can be seen that the ply pack assembly can be mounted to the back plate 27 in a "rear installation" configuration. One or more fastening features 28 can be provided on the back plate 27. These fastening features 28 can be complementary or aligned with one or more fastening features on the ply assembly 11. Non-limiting examples of fastening features 28 include (but are not limited to) one or more locking tabs, one or more fasteners, adhesives or welds between the back plate 27 and the ply assembly, or one or more mechanical mounting mechanisms for connecting the ply pack assembly 11 to the back plate 27. Any known mounting methods can be used; however, as shown, these methods can include simple holes provided on the back plate 27 as fastening features for engaging with fasteners, wherein the holes on the back plate 27 are aligned with mounting holes 11b provided on portions of the ply assembly 11. Figure 7 This is more clearly illustrated by showing a ply pack assembly 11 including mounting holes 11 b disposed on a mounting flange 11 a configured to rest against a rear side of a back plate 27 , with the mounting holes 11 b configured to align with one or more fastening features 28 on the back plate 27 .

[0073] from Figure 6It can be inferred that one or more plywood assemblies 11 can be located in respective external cutouts / plywood bag receiving portions 29 of the back plate 27. These external cutouts / plywood bag receiving portions 29 can be arranged along the periphery of the back plate 27 and aligned circumferentially with the waste liquid outlet hole 4 to leave space for the fixing of the plywood bag assembly 11.

[0074] Reference Figures 7 to 10 , the ply pack assembly / box 11 may include a body 11c defined by a plurality of closely spaced plies 11d, which extend between a mounting flange 11a and an end face 11e. The plies 11d preferably extend substantially vertically between the mounting flange 11a and the end face 11e, and are preferably parallel to each other. In addition, the plies 11d are configured to extend obliquely relative to the radial direction of the rotational center axis 21, so that the ply surface provides a positive or negative angle of attack in a purely radial flow direction relative to the rotational center axis 21. Each ply pack assembly / box 11 may include an inlet side 11f for receiving fluid entering between the plies 11d, and an outlet side 11g for discharging fluid between the plies 11d. The inlet side 11f is located radially outside the outlet side 11g relative to the spiral assembly 1 and relative to its rotational center axis 21 when installed.

[0075] To improve the manufacturing process, reduce manufacturing costs, or facilitate the construction of the ply pack assembly 11, the ply 11d may be configured with a ply tab portion 11i that is aligned with and complementarily received in respective slits or notches 11h in the mounting flange 11a and end face 11e of each assembly 11. The ply 11d may then be permanently secured to the mounting flange 11a and end face 11e by welding or bonding processes. It should be understood that an interference fit may be provided between the slit / notch 11h and the ply tab portion 11i, and that other alternative manufacturing methods may also be employed.

[0076] The screw assembly 1 is located within the bowl 30 and rotates about its central axis of rotation 21 supported by one or more bushings, bearings or journals 20. The bowl 30 and the screw assembly 1 may be independent of each other and may rotate at slightly different speeds.

[0077] See also Fig.13 and Fig.14 When the spiral assembly 1 and the bowl body 30 rotate, the centrifugal slurry 32 from the inner cavity 39 is thrown toward the bowl body 30. The solid layer 37 stays near the inner surface of the bowl body 30, while the stratified liquid layer 33 migrates radially inward due to gravity and the specific gravity / density difference between the solid and liquid components in the centrifugal slurry 32.

[0078] The liquid component 33 migrates axially toward the hood 26, eventually finding an opening therethrough. The liquid component 34 that migrates radially inward enters the inlet side 11f of the laminar pack assembly 11, flows radially inward over the weir 31, enters the waste outlet port 4, and is discharged from the centrifuge 100. The liquid component 34 that migrates radially inward typically contains some entrained fine solids that increase the turbidity of the discharged clarified liquid 36.

[0079] However, due to the inclined passages formed between the laminae 11d, the undesirable fine solids are inhibited from migrating further radially inward through the laminae pack assembly 11. Thus, the radially outward migrating fine solids 35 (located between the laminae 11d), previously entrained in the radially inward migrating liquid component 34, are deflected away from the outflow side 11g of the laminae pack assembly 11, forcing them to return from whence they came through the inflow side 11f of the laminae pack assembly 11. These "rejected fine solids" eventually rejoin the solids layer 37 along the bowl 30 and travel toward the solids discharge end 8 of the centrifuge 100.

[0080] In short, by providing one or more layer pack assemblies 11 near the liquid discharge end 9 of the spiral assembly 1, the turbidity of the discharged clarified liquid 36 can be reduced. In addition, when combined with the open axial waste liquid passage 19 defined by the floating spiral / ribbon blades 7, the turbulence between the spiral device 2 and the bowl body 3 can be reduced, and the synergistic effect is to reduce fine solids entrainment, turbidity of the waste liquid product, and improve the solids recovery rate of the centrifuge 100.

[0081] In some embodiments, the layer plates 11d of the layer plate assembly 11 may include inclined plates inclined by 60 to 80 degrees, for example, about 70 degrees (±5 degrees), relative to a radial direction extending perpendicularly from the rotation center axis 21 of the spiral assembly 1, but is not limited thereto.

[0082] In some embodiments, the plate gap between the layers 11d (ie, the spacing between the layers 11d) may be about 1 to 30 mm, for example, about 2 to 6 mm, but not limited thereto. The layers 11d are preferably parallel to each other with little deviation.

[0083] The water component / liquid component 33 of the slurry enters the plate assembly 11 from the inlet side 11f and flows to the outlet side 11g. When the water component / liquid component 33 passes through the plate gaps between the plates 11d, the inclined plates achieve solid-liquid separation by hindering the radial inward movement of fine particles. The particles entrained in the water component / liquid component 33 of the slurry move radially inward, but in the channel formed between the plates 11d (through the plate gaps), they contact the surface of the plates 11d, encounter resistance, and slide back radially outward under the action of centrifugal force toward the bowl 30. The clarified water / liquid is discharged through the outlet port 11g on the radial inner side of the plate and passes through the weir section. At Figures 16 to 20 In the illustrated embodiment, the weir section may include a weir 31 formed by a portion of the mounting plate 11a (eg, an edge or an edge ring), but is not limited thereto. Figures 6 to 14 In the illustrated embodiment, the weir section may include a weir 31 formed by a portion (eg, an edge or edge ring) of the back plate 11 e and / or the weir plate 23 , but is not limited thereto.

[0084] When small diameter solid particles enter between the layer plate assembly 11 and the layer plate 11d, they are subjected to the velocity of the water flow in the channel therebetween. The radially inward component of the velocity of the water flow in the channel "lifts" the particles away from the bowl 30 toward the outflow side 11g of the layer plate assembly 11. However, the extremely large centrifugal force acts radially outward on the particles, causing the small diameter particles to hit the inclined surface of the layer plate 11d and slide out of the layer plate channel entrance. Therefore, many small diameter solid particles return to the inflow side 11f from which they entered, and preferably re-combine with the solid layer 37 formed near the bowl 30.

[0085] In previous prior art designs, the non-floating helical blade design within the first section 16 creates some turbulence as the liquid attempts to flow toward the weir 31 and exit the centrifuge 100. This turbulence can cause a significant amount of particles (e.g., approximately 0.045 mm particles) to be drawn from the solids layer 37 and exit through the weir 31 along with the exiting clarified liquid 36.

[0086] The unique design of the floating spiral blade 7 and its position (i.e., near the first end 9 of the spiral device) reduce the local turbulence of the fluid, allowing the fine solids discharged from the layer plate to easily settle on the solid layer formed near the surface of the bowl body 30. In addition, the design of the floating ribbon blade 7 can easily allow a smaller blade portion to run under the layer plate inlet section 11f to prevent the accumulation of particles and cause discharge blockage.

[0087] As Fig.19 and Fig. 20 As shown, it should be understood that the features of the disclosed embodiments can be in the sieve bowl ( Fig.19 ) and solid bowl ( Fig. 20 ), but not limited to this.

[0088] It should be understood that the specific features, functions, process steps and possible advantages described in detail herein are merely exemplary and should not limit the spirit and / or scope of the present invention.

[0089] Furthermore, although the present invention has been described in terms of specific embodiments and applications, those skilled in the art, given this teaching, may generate additional embodiments and modifications without departing from the spirit of the invention as claimed.

[0090] Therefore, it should be understood that the drawings and descriptions herein are provided by way of example only to facilitate understanding of the present invention and should not be construed as limiting the scope thereof.

[0091] Reference numerals list

[0092] 1 Spiral assembly

[0093] 2 Screw device

[0094] 3 End cover

[0095] 4 Waste liquid outlet hole

[0096] 5 Pipeline

[0097] 6 Spiral / ribbon blades (conical)

[0098] 7 Floating spiral / ribbon blades

[0099] 8 Second end (solid discharge end)

[0100] 9 First end (waste liquid discharge end)

[0101] 10 Slurry feed port

[0102] 11-layer board package assembly / box

[0103] 11a Mounting flange

[0104] 11b Mounting holes

[0105] 11c Main Body

[0106] 11d laminate

[0107] 11e End Face

[0108] 11f Inlet side

[0109] 11g Outlet side

[0110] 11h Slit / Notch

[0111] 11i Layer plate tab part

[0112] 12 Support

[0113] 13 Raised seat

[0114] 14 Slurry opening

[0115] 15 Spiral / ribbon blades (discharge)

[0116] 16. Paragraph 1

[0117] 17 Middle

[0118] 18 Paragraph 2

[0119] 19 Open axial waste channel

[0120] 20 Bushing / Bearing / Journal

[0121] 21 Rotation center axis

[0122] 22 Inner baffle

[0123] 23 Weir plate

[0124] 24 Spiral Wall

[0125] 25 Side guard

[0126] 26 Hood

[0127] 27 Back Panel

[0128] 28 Fastening features (such as locking tabs, fasteners, adhesives, or mounting mechanisms)

[0129] 29 External cutout / laminate package assembly receiving section

[0130] 30 bowl

[0131] 31 Weir

[0132] 32 Centrifugal slurry

[0133] 33 Liquid component layer (farthest from the bowl 30)

[0134] 34 Liquid components migrating radially inward

[0135] 35 Entrained fine solids migrating radially outward (between the layers 11d)

[0136] 36 Discharge of clear liquid

[0137] 37 Solid component layering (close to bowl 30)

[0138] 38 Solid-Liquid Interface

[0139] 39 Lumen

[0140] 40 Slurry opening

[0141] 100 Centrifuge

Claims

1. A spiral assembly (1) for a centrifuge (100), the spiral assembly (1) comprising: A screw device (2) configured to be positioned within a bowl (30) and having a first end (9) proximate to a waste liquid discharge and a second end (8) proximate to a solid discharge; the screw device (2) having an inner cavity (39) configured to receive a feed slurry from a pipe (5) having a feed port (10); the inner cavity (39) being defined by a tubular screw wall (4) having a plurality of slurry openings (14) penetrating therethrough; wherein at least one screw blade (6, 7, 15) is disposed on an outer portion of the screw device (2); the screw device (2) is characterized in that it further comprises: at least one layer pack assembly (11) adjacent to the first end (9) of the screw device (2); the layer pack assembly (11) comprising a plurality of layers (11d); the layer pack assembly (11) being disposed upstream of a weir (31) or a waste liquid outlet port (4) for allowing a liquid component (33) of the feed slurry to be discharged from the centrifuge (100); The plurality of layers (11d) are configured and arranged to radially deflect fine solids (35) entrained in a liquid component (33) outwardly, or at least hinder their radial inward migration before the liquid component (33) passes between the layers (11d) and before the liquid component passes through a weir (31) or a waste liquid outlet hole (4), thereby producing a discharged clarified liquid (36) that is substantially free of fine solids (35).

2. The spiral assembly (1) for a centrifuge (100) according to claim 1, wherein: At least one ply pack assembly (11) is received in the external cutout (29), the waste drain (4) or the ply pack receiving portion (29) disposed on a portion of the back plate (27).

3. A screw assembly (1) for a centrifuge (100) according to any one of the preceding claims, wherein: At least one ply pack assembly (11) includes a mounting flange (11b) configured to be fastened to a back plate (27) or an end cap plate (3).

4. A screw assembly (1) for a centrifuge (100) according to any one of the preceding claims, wherein: At least one ply pack assembly (11) includes an end face (11e), wherein a ply (11d) is captured between the end face (11e) and a mounting flange (11a).

5. The spiral assembly (1) for a centrifuge (100) according to claim 4, wherein: The end face (11e) and the mounting flange (11a) are provided with slits or slots (11h) configured to receive and / or support the tab portion (11i) of the ply (11d) and facilitate the manufacture of the ply pack assembly (11).

6. A screw assembly (1) for a centrifuge (100) according to any one of the preceding claims, wherein: An end face (11e) of at least one ply pack assembly (11) abuts a weir plate (23) comprising the weir (31) or back plate (27).

7. The spiral assembly (1) for a centrifuge (100) according to claim 6, wherein: The weir plate (23) is adjacent to the end cover plate (3) which contains the waste liquid outlet opening (4).

8. A screw assembly (1) for a centrifuge (100) according to any one of the preceding claims, wherein: When the centrifuge (100) is in operation, the inlet side (11f) of at least one layer plate package assembly (11) is located radially inside the solid-liquid interface (36) relative to the rotation center axis (21), and is positioned radially outside the outlet side (11g) of at least one layer plate package assembly (11).

9. A spiral assembly (1) for a centrifuge (100) according to any one of the preceding claims, comprising a plurality of ply pack assemblies (11), wherein: An annular shroud (26) separates and / or spans an inlet side (11f) of each of the plurality of ply pack assemblies (11), the annular shroud (26) being configured to deflect a liquid component (33) toward the inlet side (11f) of each of the plurality of ply pack assemblies (11).

10. A screw assembly (1) for a centrifuge (100) according to any one of the preceding claims, wherein: At least one ply pack assembly (11) is removable and / or replaceable to facilitate cleaning or maintenance.

11. The spiral assembly (1) for a centrifuge (100) according to claim 10, wherein: At least one ply pack assembly (11) is removable and / or replaceable only from the first end (9) of the spiral assembly (1) for cleaning or maintenance.

12. The spiral assembly (1) for a centrifuge (100) according to any one of the preceding claims, further comprising a bowl (30); wherein: The bowl body (30) is selected from a sieve bowl or a solid bowl.

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