CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a PCT international application which claims the benefit of U.S.

Provisional Patent Application No. 62/467,711 filed on 6 Mar 2017. The aforementioned application is hereby incorporated by reference for any and all purposes as if fully set forth herein.

FIELD OF THE INVENTION

Embodiments of the invention relate to equipment and processes for dewatering slurry. In particular, embodiments of the invention relate to thickener/clarifier technology and industrial sedimentation. More particularly, embodiments of the invention relate to the advancement of spiral rake thickener technology.

BACKGROUND OF THE INVENTION

Various techniques may be used in the separation of suspended solid particles from the liquid in which they are suspended. These techniques may include, for example, flotation, filtration, centrifugation, expression and sedimentation.

Conventionally, the technique of sedimentation includes introducing a slurry (i.e., a liquid containing suspended solid particles) into a settling tank or basin of, for example, a clarifier or thickener, and allowing the suspended solid particles to settle by gravity to form a sludge or thickened mud on the bottom of the tank and a clarified liquor at the top of the tank. The sludge may then be collected and further processed or otherwise disposed of. Likewise, the supernatant liquid, also referred to as the clarified liquor, may be collected for further processing or disposal, or possibly reused to assist in a similar separation process.

In introducing the influent stream of slurry into the settling tank, it is desirable to control the flow of such a stream so as to avoid, or at least minimize, the disruption of the sludge formed along the bottom of the tank. Undue disruption of the sludge causes particles to become suspended within the supernatant liquid, once again resulting in an inefficient sedimentation process. In an effort to control the flow and distribution of the influent slurry, a feedwell may be positioned to receive the slurry as it is introduced into the settling tank.

Conventionally, a feedwell includes an area or compartment within the settling tank but which is separated from the contents of the settling tank. The influent stream of slurry is then directed along a predetermined flow path to dissipate the kinetic energy associated with the flow of the influent stream of slurry. This is done so that the influent stream has reduced flow characteristics as it leaves the separated compartment and is intermixed with the contents of the settling tank. Furthermore, the feedwell may be configured to control the distribution of the influent stream into the settling tank such that the influent stream is not introduced at a single location within the settling tank. In essence, the feedwell reduces the velocity of the influent stream and provides increased distribution of the influent stream such that any associated turbulence, which would likely disrupt the sludge formed along the bottom of the settling tank, is reduced or eliminated. Typically, a rake is used to encourage settled solids (i.e., sludge), which forms along the bottom of the tank, radially inwardly and towards a central lower opening, where it can be evacuated from the basin. After migrating towards the center of the thickener/clarifier device, the sludge may be removed via a center outlet of the settling tank via gravity or by a pump. Various rake designs have been employed over the years and may include "DORR-type" blades mounted on a 4-arm rotating framework rake. While some rake arms have comprised spiral design elements in the past, for example, as seen in a single-compartment rotary rake thickener, the inventors propose a new design which aims to alleviate short circuiting, prevent exceeding target residence time, and provide a robust solution which better approximates plug flow. See, for example, WO /2004/033063, U.S. Patent No. 5,435,924, and U.S. Patent No. 1,960,707 for examples of past rake assemblies. See also, European Patent No. EP 0629423, U.S. Patent No. 2,589, 298, U.S. Patent No. 2, 528,051, Denver published bulletin T5-B6 titled "Improved Spiral Rake Thickeners," and page 14 of chapter 15 (figure 13) of the Taggart Handbook of Mineral Dressing - Ores and Industrial Materials College Edition - Wiley Handbook Series, published by John Wiley & Sons Inc. (1945). The problem with conventional rake arms, is that they functionally tend to interruptedly move sludge towards the center of a settling tank, repeatedly engaging slurry, moving the sludge radially inwardly for a distance, until the sludge disengages the rake blade (via succumbing to viscous effects that encourage settled sludge to eventually slide over the top of the rake blade and stop its movement until another rake blade can pick it up). Thus, it would be advantageous to provide a method and apparatus for moving settled solids towards the center of a thickener/clarifier apparatus continuously and smoothly, without the detrimental effects found with conventional rake designs.

Large, high-density thickener/clarifiers can perform worse than smaller laboratory test units after the application of scale up calculations. Such underperformance in the field may be, at least in part, attributed to large distributions in mud residence times that can be seen with full-scale industrial-sized units. To elaborate, thickener/clarifiers are generally designed so that settled mud flows and moves out of the thickener/clarifier's lower discharge by way of plug flow; wherein in theory, mud within the thickener/clarifier is supposed to thicken up evenly over a designed residence time. However, in reality, some mud within a large, high- density thickener/clarifiers may short circuit to the thickener/clarifier's discharge before it has resided long enough to thicken up to its target or "designed" underflow density (i.e., some discharged material may be below a target density). Conversely, some of the settled material can end up remaining in the thickener/clarifier for much longer than its intended design residence time, and therefore, it may thicken well beyond the target density.

Material that remains in the thickener/clarifier for longer- than-designed periods, or for longer-than-intended periods may thicken to slightly higher than design underflow density, and this may lead to high yield stress and torque on a rake assembly and/or drive thereof. In some cases, thickener/clarifiers that provide broad residence time distributions (compared with an ideal plug flow model) may negatively result in both lower overall underflow density and higher exhibited torque.

OBJECTS OF THE INVENTION

It is, therefore, an object of some embodiments of the present invention, to provide an improved rake for a thickener/clarifier which may be adequately configured to encourage settled solids to migrate towards the center of a settling tank.

It is a further object of some embodiments of the present invention, to provide an improved rake for a thickener/clarifier which may be adequately configured to continuously and preferably uninterruptedly move settled solids to a central lower opening, where it can be removed, without limitation.

It is a further object of some embodiments of the present invention, to provide an improved rake for a thickener/clarifier which may be adequately configured with an innovative spiral rake design, without limitation. It is a further object of some embodiments of the present invention, to provide an improved rake for a thickener/clarifier which may improve residence time distribution of settled solids, and approach theoretical plug flow models, without limitation.

It is a further object of some embodiments of the present invention, to promote more uniform distributions of settled solids, mitigate or eliminate short-circuiting (e.g., occurrences of lower underflow density prematurely leaving the thickener/clarifier), and/or reduce rake torque values, without limitation.

These and other objects of the present invention will be apparent from the drawings and description herein. Although every object of the invention 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 DESCRIPTION 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 a non-limiting preferred embodiment of a new composition of matter 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. The figures may not necessarily be to scale. They may be

representative of certain exemplary, non-limiting embodiments - or, for illustrative purposes only. The foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which:

FIGS. 1-3 show various views of one preferred embodiment of a rake assembly 100, without limitation.

FIGS. 4-6 show various views of another preferred embodiment of a rake assembly 100, without limitation. FIGS. 7 and 8 show two respective non-limiting exemplary cross-sectional views of a spiral-shaped curvilinear plow according to some embodiments.

FIGS. 9 and 10 show two respective non-limiting exemplary embodiments of a distal connection between an arm and a spiral-shaped curvilinear plow; wherein FIG. 9 shows a direct connection with little or no Z-axis vertical separation therebetween; and, wherein FIG. 10 shows an indirect connection with a Z-arm separating a distal end portion (B) of an arm from a distal end portion (B) of a spiral-shaped curvilinear plow.

FIG. 11 suggests how an aspect ratio of rake assembly features may change to accommodate shallower thickener/clarifiers as well as deeper paste cone thickeners, without limitation.

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

SUMMARY OF THE INVENTION

Disclosed, is a rake assembly 100 for a thickener/clarifier. The rake assembly 100 may comprise a rake support assembly 80; a number of optional mounting members (e.g., an optional first mounting member 86, an optional second mounting member 86, an optional third mounting member, an optional fourth mounting member); a first arm 10; a fifth arm 11 ; a second arm 12; and a sixth arm 13 each extending radially outwardly from the rake support assembly 80. A first spiral-shaped curvilinear plow 40 and a second spiral-shaped curvilinear plow 42 may extend radially outwardly away from the rake support assembly 80 in a curvilinear fashion as depicted in the figures. A distal end portion (B) of the first spiral-shaped curvilinear plow 40 may be connected to the distal end portion (B) of the first arm 10, and the proximal end portion (A) of the first spiral-shaped curvilinear plow 40 may be connected to the rake support assembly 80, for example, via the optional first mounting member 86. A distal end portion (B) of the second spiral- shaped curvilinear plow 42 may be connected to the distal end portion (B) of the second arm 12, and the proximal end portion (A) of the second spiral- shaped curvilinear plow 42 may be connected to the rake support assembly 80; for example, via the optional second mounting member 86. In some preferred embodiments, the first spiral- shaped curvilinear plow 40 may be operatively connected to the fifth arm 11 via a first connector 50; the first spiral-shaped curvilinear plow 40 may be operatively connected to the second arm 12 via a second connector 60; and, the second spiral-shaped curvilinear plow 42 may be operatively connected to the sixth arm 13 via a third connector 52, without limitation.

In some embodiments, at least one circumferential support member 30 may connect the first arm 10 to the fifth arm 11, without limitation. In some embodiments, the at least one circumferential support member 30 may connect the fifth arm 11 to the second arm 12, without limitation. In some embodiments, the at least one circumferential support member 30 may connect the second arm 12 to the sixth arm 13, without limitation. In some embodiments, the at least one circumferential support member 30 may be adapted to support tensile forces and/or adapted to support compressive forces, without limitation. In some embodiments, the first and second mounting members 86, if and where employed, may each comprise, for example, a short cantilevered arm extending radially outwardly from the rake support assembly 80. For example, the first and second mounting members 86 may each comprise a proximal end portion (A) located proximate a radially inward end, and a distal end portion (B) located proximate a radially outward end. It should be understood that spiral-shaped curvilinear plows disclosed herein may connect directly or indirectly to any portion of the column using connection means known in the art (e.g., bolting, welding, connectors, gussets, mounts, butt joint, flange, or the like, without limitation).

The rake assembly 100 may further comprise a third arm 14 extending radially outwardly from the rake support assembly 80. The third arm 14 may have a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end. The second spiral- shaped curvilinear plow 42 may be connected to the third arm 14 via a fourth connector 62. In some embodiments, the rake assembly 100 may comprise a seventh arm 15 extending radially outwardly from the rake support assembly 80 and also having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end, without limitation. A third spiral-shaped curvilinear plow 44 may extend radially outwardly away from the rake support assembly 80 in a curvilinear fashion. The third spiral-shaped curvilinear plow 44 may have a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end similar to the first 40 and second 42 spiral-shaped curvilinear plows. A distal end portion (B) of the third spiral-shaped curvilinear plow 44 may be connected to the distal end portion (B) of the third arm 14. A proximal end portion (A) of the third spiral-shaped curvilinear plow 44 may be connected to the rake support assembly 80; for example, via an optional third mounting member 86 of the rake support assembly 80. The third spiral-shaped curvilinear plow 44 is operatively connected to the seventh arm 15 via a fifth connector 54.

According to some preferred embodiments, the first connector 50 or the third connector 52 of the rake assembly 100 may be shorter in a vertical direction than the second connector 60. For example, both the first connector 50 and the third connector 52 may be shorter in the vertical direction than the second connector 60, without limitation. According to some preferred embodiments, the third connector 52 or the fifth connector 54 of the rake assembly 100 may be shorter in a vertical direction than the fourth connector 62. For example, both the third connector 52 and the fifth connector 54 may be shorter in the vertical direction than the fourth connector 62, without limitation. The first connector 50, the third connector 52, and the fifth connector 54 may all be the same first length in the vertical direction, without limitation. The second connector 60 and the fourth connector 62 may also be the same second length in the vertical direction. The first length is less than the second length, without limitation. In some non-limiting embodiments, the first 50, second 60, third 52, fourth 62, and fifth 54 connectors may each be generally vertically-oriented such that they are substantially parallel to a longitudinal axis 81 of the rake support assembly 80, without limitation.

The first spiral-shaped curvilinear plow 40 of the rake assembly 100 may be operatively connected to the sixth arm 13 via a sixth connector 70, without limitation. The second spiral- shaped curvilinear plow 42 may be operatively connected to the seventh arm 15 via a seventh connector 72, without limitation. Embodiments of a rake assembly 100 may further comprise a fourth arm 16 extending radially outwardly from the rake support assembly 80 and having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end, without limitation. The third spiral-shaped curvilinear plow 44 may be connected to the fourth arm 16 via an eighth connector 64.

The rake assembly 100 may also comprise an eighth arm 17 extending radially outwardly from the rake support assembly 80 and having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end. The third spiral-shaped curvilinear plow 44 may be connected to the eighth arm 17 via a ninth connector 74. A fourth spiral-shaped curvilinear plow 46 may be provided and extend radially outwardly away from the rake support assembly 80 in a curvilinear fashion - having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end. The distal end portion (B) of the fourth spiral-shaped curvilinear plow 46 may be connected to the distal end portion (B) of the fourth arm 16. The proximal end portion (A) of the fourth spiral-shaped curvilinear plow 44 may be connected to the rake support assembly 80; for example; via an optional fourth mounting member 86 of the rake support assembly 80. The fourth spiral-shaped curvilinear plow 46 may be operatively connected to the eighth arm 17 via a tenth connector 56, without limitation. The fourth spiral-shaped curvilinear plow 46 may be operatively connected to the first arm 10 via an eleventh connector 66, without limitation. The fourth spiral-shaped curvilinear plow 46 may be operatively connected to the fifth arm 11 via a twelfth connector 76, without limitation.

According to some embodiments, the first 50, third 52, fifth 54, and tenth 56 connectors of the rake assembly 100 may be positioned radially outwardly of the second 60, fourth 62, eighth 64, and eleventh 66 connectors, without limitation. According to some embodiments, the second 60, fourth 62, eighth 64, and eleventh 66 connectors may be positioned radially outwardly of the sixth 70, seventh 72, ninth 74, and twelfth 76 connectors, without limitation.

The rake assembly 100 may comprise a fourth arm 16 extending radially outwardly from the rake support assembly 80. The fourth arm 16 may have a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end, without limitation. The rake assembly 100 may comprise an eighth arm 17 extending radially outwardly from the rake support assembly 80 and having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end, without limitation. A fourth spiral-shaped curvilinear plow 46 may be provided to the rake assembly 100; the fourth spiral-shaped curvilinear plow 46 extending radially outwardly away from the rake support assembly 80 in a curvilinear fashion and having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end. The distal end portion (B) of the fourth spiral-shaped curvilinear plow 46 may be connected to the distal end portion of the fourth arm 16. The proximal end portion (A) of the fourth spiral-shaped curvilinear plow 46 may be connected to a fourth mounting member 86 of the rake support assembly 80, without limitation. According to some embodiments, the third spiral- shaped curvilinear plow 44 may be operatively connected to the fourth arm 16 via an eighth connector 64, without limitation. According to some embodiments, the fourth spiral-shaped curvilinear plow 46 may be operatively connected to the eighth arm 17 via a tenth connector 56, without limitation.

According to some embodiments, the fourth spiral-shaped curvilinear plow 46 may be operatively connected to the first arm 10 via an eleventh connector 66, without limitation. In some non-limiting embodiments, the first 50, third 52, fifth 54, and tenth 56 connectors of the rake assembly 100 may be positioned radially outwardly of the second 60, fourth 62, eighth 64, and eleventh 66 connectors, without limitation.

Embodiments of the rake assembly 100 may comprise a fifth spiral-shaped curvilinear plow 41 extending radially outwardly from the rake support assembly 80 in a curvilinear fashion and having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end; wherein the distal end portion (B) of the fifth spiral-shaped curvilinear plow 41 may be connected to the distal end portion of the fifth arm 11. For example, a fifth spiral-shaped curvilinear plow 41 may be provided between a first spiral-shaped curvilinear plow 40 and a second spiral-shaped curvilinear plow 42, without limitation.

Embodiments of the rake assembly 100 may comprise a sixth spiral-shaped curvilinear plow 43 extending radially outwardly away from the rake support assembly 80 in a curvilinear fashion and having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end; wherein the distal end portion (B) of the sixth spiral-shaped curvilinear plow 43 is connected to the distal end portion of the sixth arm 13. For example, a sixth spiral-shaped curvilinear plow 43 may be provided between a second spiral-shaped curvilinear plow 42 and a third spiral-shaped curvilinear plow 44, without limitation. Embodiments of the rake assembly 100 may comprise a seventh spiral-shaped curvilinear plow 45 extending radially outwardly away from the rake support assembly 80 in a curvilinear fashion and having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end; wherein the distal end portion (B) of the seventh spiral-shaped curvilinear plow 45 is connected to the distal end portion of the seventh arm 15. For example, a seventh spiral-shaped curvilinear plow 45 may be provided between a third spiral-shaped curvilinear plow 44 and a fourth spiral-shaped curvilinear plow 46, without limitation.

Embodiments of the rake assembly 100 may comprise an eighth spiral-shaped curvilinear plow 47 extending radially outwardly away from the rake support assembly 80 in a curvilinear fashion and having a proximal end portion (A) located proximate its radially inward end, and a distal end portion (B) located proximate its radially outward end; wherein the distal end portion (B) of the eighth spiral-shaped curvilinear plow 47 is connected to the distal end portion of the eighth arm 17. For example, an eighth spiral-shaped curvilinear plow 47 may be provided between a fourth spiral-shaped curvilinear plow 46 and a first spiral-shaped curvilinear plow 40, without limitation.

In some embodiments, the fifth spiral-shaped curvilinear plow 41 may be operatively connected to the second arm 12 via a thirteenth connector 51, without limitation. In some embodiments, the fifth spiral- shaped curvilinear plow 41 may be operatively connected to the sixth arm 13 via a seventeenth connector 61, without limitation. In some embodiments, the fifth spiral-shaped curvilinear plow 41 may be operatively connected to the third arm 14 via a twenty-first connector 71, without limitation.

In some embodiments, the sixth spiral-shaped curvilinear plow 43 may be operatively connected to the third arm 14 via a fourteenth connector 53, without limitation. In some embodiments, the sixth spiral-shaped curvilinear plow 43 may be operatively connected to the seventh arm 15 via an eighteenth connector 63, without limitation. In some embodiments, the sixth spiral-shaped curvilinear plow 43 may be operatively connected to the fourth arm 16 via a twenty-second connector 73, without limitation.

In some embodiments, the seventh spiral-shaped curvilinear plow 45 may be operatively connected to the fourth arm 16 via a fifteenth connector 55, without limitation. In some embodiments, the seventh spiral-shaped curvilinear plow 45 may be operatively connected to the eighth arm 17 via a nineteenth connector 65, without limitation. In some embodiments, the seventh spiral-shaped curvilinear plow 45 may be operatively connected to the first arm 10 via a twenty-third connector 75, without limitation.

In some embodiments, the eighth spiral-shaped curvilinear plow 47 may be operatively connected to the first arm 10 via a sixteenth connector 57, without limitation. In some embodiments, the eighth spiral-shaped curvilinear plow 47 may be operatively connected to the fifth arm 11 via a twentieth connector 67, without limitation. In some embodiments, the eighth spiral-shaped curvilinear plow 47 may be operatively connected to the second arm 12 via a twenty-fourth connector 77, without limitation.

A proximal end portion (A) of the fifth 41, sixth 43, seventh 45, and/or eighth 47 spiral- shaped curvilinear plow 44 may be connected to the rake support assembly directly, or indirectly; for example; via respective optional mounting members 86 provided to the rake support assembly 80.

In some embodiments, proximal end portions (A) of spiral-shaped curvilinear plows discussed herein may also be connected to each other; in particular, in embodiments where the rake support assembly 80 may not vertically extend below the arms.

It should be understood that any of the above technical features/elements may be employed in in various manners/combinations to arrive at different embodiments. DETAILED DESCRIPTION OF THE INVENTION

The following description of the non-limiting embodiments shown in the drawings is merely exemplary in nature and is in no way intended to limit the inventions disclosed herein, their applications, or uses.

Turning to the embodiment shown in FIGS. 1-3, a rake assembly 100 for a

thickener/clarifier may comprise a rake support assembly 80. The rake support assembly 80 may comprise a pillar, which may, as shown, comprise a number of first support members 82, for example, a number of vertically-oriented truss members, and a number of second support members 84, for example, a number of horizontally-oriented truss members or rings connecting parallel vertically-oriented truss members. It should be understood that the rake support assembly 80 could, alternatively, compose a truss, a frame, or a hollow, tubular column (e.g., a pipe). For example, rake support assembly 80 may be fabricated from rolled or flat plates welded together, or a large pipe extrusion. While some preferred embodiments may comprise a tubular lightweight design, it is envisaged that the rake support assembly 80 could be provided as a solid piece, without limitation; and it is contemplated that such embodiments would fall within the scope of a rake support assembly 80 described herein. In some embodiments, a rake support assembly 80 may be provided in the form of a rake shaft which is coupled to abridge extending over a thickener/clarifier, without limitation; and such embodiments would also fall within the scope of a rake support assembly 80 described herein. In some embodiments, as shown, the column may span between arms and spiral-shaped curvilinear plows; however, in some embodiments, the column may end at the arms - wherein proximal end portions (A) may join each other

A number of mounting members 86 may be provided to a lower portion of the rake support assembly 80. For example, in some non-limiting embodiments, the mounting members 86 may comprise horizontally-oriented, radially-extending, and/or cantilevered arms as shown. Preferably, the mounting members 86, if used, may serve to attach a proximal end portion (A) of a spiral-shaped curvilinear plow to the rake support assembly 80, such that the spiral-shaped curvilinear plow may extend radially outwardly to its distal end portion (B) adjacent to a perimeter or periphery of a thickener/clarifier (not shown). Mounting members 86 may merely comprise a welded joint, a gusset, a bracket, a connection point, or an attachment point, without limitation. It is envisaged that spiral-shaped curvilinear plows discussed herein may alternatively be connected to an arm of a rake assembly at its proximal end portion (A), rather than to the rake support assembly 80, without limitation.

The rake assembly 100 may, as shown, comprise a first arm 10, a second arm 12, a third arm 14, and a fourth arm 16 each extending radially outwardly from the rake support assembly 80 and circumferentially-spaced from each other. As shown, circumferential spacing may be even-spacing, without limitation. The rake assembly 100 may, as shown, comprise a fifth arm 11, a sixth arm 13, a seventh arm 15, and an eighth arm 17. As suggested in FIG. 1, the fifth 11, sixth 13, seventh 15, and eighth 17 arms may be interposed between the first 10, second 12, third 14, and fourth 14 arms, respectively. Moreover, as suggested in the embodiment of FIGS. 1-3, the fifth 11, sixth 13, seventh 15, and eighth 17 arms may be shorter than, and/or extend radially outwardly from the rake support assembly 8 for a distance which is less than the first 10, second 12, third 14, and fourth 14 arms, respectively. However, as suggested in the embodiment of FIGS. 4-6, arms 10, 11, 12, 13, 14, 15, 16, 17 may be of similar length, without limitation.

One or more circumferential support members 30 may extend between any of the arms 10, 11, 12, 13, 14, 15, 16, 17, and these circumferential support members 30 may comprise any structural element including, but not limited to, cables, trusses, rigid elongated members, bars, ties, straps, chains, or the like, without limitation. The circumferential support members 30 are preferably able to support tensile load, but may also support compressive and torque loads as well, without limitation. A number of connection points 20 may be located at junctions between an arm 10, 11, 12, 13, 14, 15, 16, 17 and its adjacent respective circumferential support member 30 as shown. Connection points may be of the connector type which is suitable to connect arms 10, 11, 12, 13, 14, 15, 16, 17 to circumferential support members 30, and may include, without limitation, structural elements such as eyebolts, cable mounts, weld plates, turnbuckles, bolted connections, and/or the like.

The rake assembly 100 may comprise a first spiral-shaped curvilinear plow 40, a second spiral-shaped curvilinear plow 42, a third spiral-shaped curvilinear plow 44, and a fourth spiral-shaped curvilinear plow 46, without limitation. A proximal end portion (A) of the first spiral-shaped curvilinear plow 40 may be directly attached to a rake support assembly 80, or to a rake support assembly 80 via a mounting member 86 which extends from the rake support assembly 80 at a different polar radial than the first arm 10 (e.g., 180 degrees opposite from each other as shown in the non-limiting FIGS. 1-6), and a distal end portion (B) of the first spiral-shaped curvilinear plow 40 may extend to a distal outer radial portion of the first arm 10. The distal end portion (B) of the first spiral-shaped curvilinear plow 40 may be connected directly or indirectly to the distal outer radial portion of the first arm 10, without limitation. Similar to the first spiral-shaped curvilinear plow 40, and as shown, a distal end portion (B) of the second spiral-shaped curvilinear plow 42 may extend to a distal outer radial portion of the second arm 12; a distal end portion (B) of the third spiral-shaped curvilinear plow 44 may extend to a distal outer radial portion of the third arm 14, and a distal end portion (B) of fourth spiral-shaped curvilinear plow 46 may extend to a distal outer radial portion of the fourth arm 16.

A first connector 50 provided to an outer portion of the fifth arm 11 may be provided to support the first spiral-shaped curvilinear plow 40, without limitation. In lieu of, or in addition to the first connector 50, a second connector 60 provided to a central portion of the second arm 12 may be provided to support the first spiral-shaped curvilinear plow 40, without limitation. Optionally, a sixth connector 70 may be provided to an inner portion of the sixth arm 13 in order to support the first spiral-shaped curvilinear plow 40, without limitation.

Similarly, a third connector 52 provided to an outer portion of the sixth arm 13 may be provided to support the second spiral-shaped curvilinear plow 42, without limitation. In lieu of, or in addition to the third connector 52, a fourth connector 62 provided to a central portion of the second arm 14 may be provided to support the second spiral-shaped curvilinear plow 42, without limitation. Optionally, a seventh connector 72 may be provided to an inner portion of the seventh arm 15 in order to support the second spiral-shaped curvilinear plow 42, without limitation.

Similarly, a fifth connector 54 provided to an outer portion of the seventh arm 15 may be provided to support the third spiral-shaped curvilinear plow 44, without limitation. In lieu of, or in addition to the fifth connector 54, an eighth connector 64 provided to a central portion of the fourth arm 14 may be provided to support the third spiral-shaped curvilinear plow 44, without limitation. Optionally, a ninth connector 74 may be provided to an inner portion of the eighth arm 17 in order to support the third spiral-shaped curvilinear plow 44, without limitation.

Similarly, a tenth connector 56 provided to an outer portion of the eighth arm 17 may be provided to support the fourth spiral-shaped curvilinear plow 46, without limitation. In lieu of, or in addition to the tenth connector 56, an eleventh connector 66 provided to a central portion of the first arm 10 may be provided to support the fourth spiral-shaped curvilinear plow 46, without limitation. Optionally, a twelfth connector 76 may be provided to an inner portion of the fifth arm 11 in order to support the fourth spiral-shaped curvilinear plow 46, without limitation. As suggested in the embodiment shown in FIGS. 4-6, the rake assembly 100 may comprise a fifth spiral-shaped curvilinear plow 41, a sixth spiral-shaped curvilinear plow 43, a seventh spiral-shaped curvilinear plow 45, and an eighth spiral-shaped curvilinear plow 47, without limitation. A proximal end portion (A) of the fifth spiral-shaped curvilinear plow 41 may be directly attached to a rake support assembly 80, or to a rake support assembly 80 via to a mounting member 86 which extends from the rake support assembly 80 at a different polar radial than the fifth arm 11 (e.g., 180 degrees opposite from each other as shown in the non- limiting FIGS. 3-6), and a distal end portion (B) of the fifth spiral-shaped curvilinear plow 41 may extend to a distal outer radial portion of the fifth arm 11. The distal end portion (B) of the fifth spiral-shaped curvilinear plow 41 may be connected directly or indirectly to the distal outer radial portion of the fifth arm 11, without limitation. Similar to the fifth spiral-shaped curvilinear plow 41, and as shown in FIGS. 3-6, a distal end portion (B) of the sixth spiral- shaped curvilinear plow 43 may extend to a distal outer radial portion of the sixth arm 13; a distal end portion (B) of the seventh spiral-shaped curvilinear plow 45 may extend to a distal outer radial portion of the seventh arm 15, and a distal end portion (B) of eighth spiral-shaped curvilinear plow 47 may extend to a distal outer radial portion of the eighth arm 17.

A thirteenth connector 51 provided to an outer portion of the second arm 12 may be provided to support the fifth spiral-shaped curvilinear plow 41, without limitation. In lieu of, or in addition to the thirteenth connector 51, a seventeenth connector 61 provided to a central portion of the sixth arm 13 may be provided to support the fifth spiral-shaped curvilinear plow 41, without limitation. Optionally, a twenty-first connector 71 may be provided to an inner portion of the third arm 14 in order to support the fifth spiral- shaped curvilinear plow 41, without limitation.

Similarly, a fourteenth connector 53 provided to an outer portion of the third arm 14 may be provided to support the sixth spiral-shaped curvilinear plow 43, without limitation. In lieu of, or in addition to the fourteenth connector 53, an eighteenth connector 63 provided to a central portion of the seventh arm 15 may be provided to support the sixth spiral-shaped curvilinear plow 43, without limitation. Optionally, a twenty-second connector 73 may be provided to an inner portion of the fourth arm 16 in order to support the sixth spiral-shaped curvilinear plow 43, without limitation.

Similarly, a fifteenth connector 55 provided to an outer portion of the fourth arm 16 may be provided to support the seventh spiral-shaped curvilinear plow 45, without limitation. In lieu of, or in addition to the fifteenth connector 55, a nineteenth connector 65 provided to a central portion of the eighth arm 17 may be provided to support the seventh spiral-shaped curvilinear plow 45, without limitation. Optionally, a twenty-third connector 75 may be provided to an inner portion of the first arm 10 in order to support the seventh spiral-shaped curvilinear plow 45, without limitation.

Similarly, a sixteenth connector 57 provided to an outer portion of the first arm 10 may be provided to support the eighth spiral-shaped curvilinear plow 47, without limitation. In lieu of, or in addition to the sixteenth connector 57, a twentieth connector 67 provided to a central portion of the fifth arm 11 may be provided to support the eighth spiral-shaped curvilinear plow 47, without limitation. Optionally, a twenty-fourth connector 77 may be provided to an inner portion of the second arm 12 in order to support the eighth spiral-shaped curvilinear plow 47, without limitation.

Turning now to FIG. 7, as depicted in the figure, any spiral-shaped curvilinear plow 40' described herein may comprise a leading edge 40a' which is backed by a tubular support member 40b' in order to provide rigidity and/or strength. The two may be joined together by fasteners or one or more welds 40c'. Turning now to FIG. 8, as depicted in the figure, any spiral-shaped curvilinear plow 40" described herein may comprise a leading edge 40a" which is backed by a tubular support member 40b" in order to provide rigidity and/or strength. The two may be joined together by fasteners or one or more welds 40c', via one or more connecting members 40d" extending therebetween. The provided non-limiting examples depicted are for illustrative purposes only.

Turning now to FIGS. 9 and 10, it should be appreciated that distal end portions (B) of an arm 10 and its respective spiral-shaped curvilinear plow 40 may be closely arranged and connected together as shown in the non-limiting embodiment of FIG. 9. Or, in some embodiments, distal end portions (B) of an arm and a spiral-shaped curvilinear plow 40 may be separated in a vertical direction (i.e., "Z-axis"), and operatively connected to each other, via a Z-arm, without limitation. The Z-arm vertical extension member may allow some or all rake arms 10 to be lifted vertically out of denser settled solids and into clarified liquor - thereby reducing drag and torque needed to drive the spiral rake assembly. The vertical distance of the Z-arm may be increased, in some embodiments, such that the arms 40 may be entirely displaced from all liquid-containing portions of a thickener/clarifier, further reducing drag and torque needed to drive the spiral rake assembly.

Although the invention has been described in terms of particular embodiments and applications, 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. For example, low aspect-ratio thickener/clarifiers and their respective rake assemblies 100 are shown as non-limiting exemplary embodiments in the figures.

However, it should be understood that a rake assembly 100 may be sized and/or shaped to any type of thickener/clarifier, including those having higher aspect ratios (i.e., "deeper" in the vertical direction), and those having a lower aspect ratio (i.e., "shallower" in the vertical direction). Moreover, any number of the features and/or components disclosed herein may be practiced with thickener/clarifiers having high aspect rations, such as deep cone paste thickeners and high density thickeners, without limitation. Additionally, a rake assembly 100 may comprise a ratio of height in the vertical direction to width (or diameter) in the horizontal direction, which is greater than what is shown. Accordingly, it is to be understood that the descriptions herein are proffered by way of example to facilitate comprehension of the invention and should not be construed to limit the scope thereof.

REFERENCE NUMERAL IDENTIFIERS A Proximal End Portion

B Distal End Portion

10 First Arm

11 Fifth Arm

12 Second Arm

13 Sixth Arm

14 Third Arm

15 Seventh Arm

16 Fourth Arm

17 Eighth Arm

20 Connection Point (between an Arm and Circumferential Support Member)

30 Circumferential Support Member

40 First Spiral-Shaped Curvilinear Plow

40' Spiral-Shaped Curvilinear Plow (cross sectional embodiment)

40a' Leading edge

40b' Tubular support member/backing

40c' Weld

40" Spiral-Shaped Curvilinear Plow (cross sectional embodiment)

40a" Leading edge

40b" Tubular support member/backing

40c" Weld

40d" Connecting member

41 Fifth Spiral-Shaped Curvilinear Plow

42 Second Spiral-Shaped Curvilinear Plow

43 Sixth Spiral-Shaped Curvilinear Plow

44 Third Spiral-Shaped Curvilinear Plow

45 Seventh Spiral-Shaped Curvilinear Plow

46 Fourth Spiral-Shaped Curvilinear Plow

47 Eighth Spiral-Shaped Curvilinear Plow

50 First Connector

51 Thirteenth Connector

52 Third Connector 53 Fourteenth Connector

54 Fifth Connector

55 Fifteenth Connector

56 Tenth Connector

57 Sixteenth Connector

60 Second Connector

61 Seventeenth Connector

62 Fourth Connector

63 Eighteenth Connector

64 Eighth Connector

65 Nineteenth Connector

66 Eleventh Connector

67 Twentieth Connector

70 Sixth Connector

(70) Sixth Connector (Optional)

71 Twenty-first Connector

72 Seventh Connector

(72) Seventh Connector (Optional)

73 Twenty-second Connector

74 Ninth Connector

(74) Ninth Connector (Optional)

75 Twenty-third Connector

76 Twelfth Connector

(76) Twelfth Connector (Optional)

77 Twenty-fourth Connector

80 Rake Support Assembly (e.g., rotating cage, column, tube, pole, shaft, or the like)

81 Longitudinal Axis (e.g., axis of rake support assembly 80)

82 First Support Member (e.g., vertically-oriented truss members)

84 Second Support Member (e.g., horizontally-oriented truss members)

86 Mounting Member (e.g., horizontally-oriented, radially-extending, cantilevered arms)

100 Rake Assembly (e.g., for a thickener/clarifier)