阅读说明：本技术 用于颗粒分离器的进料装置、颗粒分离器和颗粒分离方法 (Feeding device for particle separator, particle separator and particle separation method ) 是由 凯文·帕特里克·嘉尔文 于 2017-04-26 设计创作，主要内容包括：本发明提供了一种用于将进料浆料(S)供给到具有流化源(13)的颗粒分离器(1)中的装置(4)。该进料装置包括腔室(17),该腔室具有至少一个挡板(22),该挡板用于将腔室分成第一区域(20)和第二区域(21)。进料口(23)将浆料供给到第一区域(20)中,并且挡板(22)使浆料偏离第二区域(21)并将流化流体(10)从流化源(13)引导通过第二区域(21),以与来自第一区域(20)的浆料混合。还提供了包含进料装置(4)的颗粒分离器(1)和颗粒分离方法。(The invention provides an apparatus (4) for feeding a feed slurry (S) into a particle separator (1) having a fluidization source (13). The feeding device comprises a chamber (17) having at least one baffle (22) for dividing the chamber into a first zone (20) and a second zone (21). A feed inlet (23) feeds the slurry into the first zone (20), and a baffle (22) deflects the slurry away from the second zone (21) and directs fluidizing fluid (10) from the fluidizing source (13) through the second zone (21) to mix with the slurry from the first zone (20). A particle separator (1) comprising a feed device (4) and a method of particle separation are also provided.)

1. An apparatus for supplying a feed slurry to a particle separator, comprising:

a chamber having at least one tubular baffle for dividing the chamber into a first region and a second region, the second region being formed inside the baffle and the first region being formed between the outside of the baffle and the chamber;

a fluidization source for supplying a fluidizing fluid to the first opening of the baffle; and

a feed inlet to the chamber for feeding slurry to the first zone;

wherein the first opening of the baffle is proximate to the fluidization source and the second opening of the baffle is proximate to a partial particle separator having an inclined passage formed by a series of inclined plates; and

the baffle deflects the slurry away from the second region and directs fluidizing fluid from the fluidizing source through the first opening of the baffle, the second region, and the second opening of the baffle to mix with the slurry from the first region in a mixing zone provided between the second opening of the baffle and the portion of the particle separator having an inclined passage formed by a series of inclined plates.

2. The apparatus of claim 1 wherein the baffle is substantially frustoconical or cylindrical in shape.

3. The apparatus of claim 1, wherein the baffle is centrally located at one end of the chamber.

4. The apparatus of claim 1 wherein (a) the inner diameter of the baffle gradually increases from the baffle opening, (b) the inner diameter of the baffle gradually decreases from the baffle opening or (c) the inner diameter of the baffle is substantially the same as the diameter of the fluidization source along its length, (d) the fluidization source has a constant inner diameter and the first opening of the baffle has an inner diameter that is substantially the same as the constant inner diameter of the fluidization source or (e) the inner diameter of the first opening of the baffle is initially the same or nearly the same as the inner diameter of the fluidization chamber closest to the baffle.

5. The apparatus of claim 1, wherein the feed inlet is arranged to feed slurry tangentially relative to a sidewall of the chamber to induce a rotational flow of the slurry in the first zone.

6. An apparatus according to claim 1, wherein there are two feed inlets located on opposite sides of the side wall of the chamber, preferably adjacent to the first opening of the baffle, to feed the feed slurry at a point directly above the point of intersection between the chamber and the fluidising source.

7. The device of claim 1, wherein the chamber has a side wall diverging from the feed opening of the chamber, and preferably the chamber is substantially cylindrical or frusto-conical in shape.

8. The apparatus of claim 1, wherein the baffle is located near one end of the chamber to form a gap between the baffle and the one end, the gap preferably being annular in shape to allow denser and/or larger sized particles to flow through the gap along at least one sidewall of the chamber.

9. The apparatus of claim 8, wherein the gap has a width ≧ 3 x η, where η is the maximum particle size in the feed slurry.

10. An apparatus for separating low density and/or smaller size particles from a feed slurry, the apparatus comprising:

the feeding device according to claim 1;

wherein a plurality of angled passages are located near a first end of the chamber; and

wherein the fluidization source is located near the second end of the chamber.

11. The apparatus of claim 10, wherein the fluidization source comprises a fluidization chamber having a fluidization bed to generate a fluidization fluid, the baffle being located near the second end of the chamber to form a gap between the baffle, the second end, and the fluidization chamber, the gap preferably being annular in shape to allow denser and/or larger sized particles to flow into the fluidization chamber along at least one sidewall of the chamber.

12. The apparatus of claim 11, wherein the gap has a width ≧ 3 x η, where η is the maximum particle size of the feed slurry.

13. The apparatus of claim 10, wherein (a) the ratio of the height of the fluidized bed to the diameter of the fluidization chamber is ≥ 1; (b) the ratio of the combined height of the fluidization chamber and the baffle to the diameter of the fluidization chamber is more than or equal to 2; (c) the ratio of the height of the device to the diameter of the fluidization chamber is more than or equal to 3; or any combination of (a) to (c).

14. A method for feeding a slurry into a particle separator having a fluidization source, comprising:

dividing a chamber into a first region and a second region by a baffle, the baffle having two open ends, the second region being formed inside the baffle and the first region being formed between an outside of the baffle and the chamber;

supplying the slurry to the first zone;

deflecting the slurry away from the second region; and

wherein fluidizing fluid is directed from the fluidizing source into one open end of the baffle and through the second region and through the other open end of the baffle to produce a fluidizing stream that mixes with the slurry from the first region in a mixing zone provided between the baffle and a portion of the particle separator having an inclined passage formed by a series of inclined plates.

15. The method of claim 14, further comprising: (a) feeding the slurry tangentially relative to a sidewall of the chamber; (b) feeding the slurry so as to induce a rotational flow of the slurry in the first zone; and/or (c) on an opposite side of a sidewall of the chamber, preferably adjacent to the first opening of the baffle, to feed the slurry at a point directly above the intersection between the chamber and the fluidization source.

16. The method of claim 14, wherein the second region is surrounded by the first region.

17. The method of claim 14, further comprising positioning the baffle near one end of the chamber to form a gap between the baffle and the one end, the gap preferably being annular in shape, thereby allowing denser and/or larger sized particles to flow through the gap along at least one sidewall of the chamber.

18. The method of claim 14, further comprising forming the chamber with diverging sidewalls to direct a flow of denser and/or larger sized particles in the chamber, or providing the first opening of the baffle with an inner diameter that is initially the same or nearly the same as an inner diameter of the fluidization chamber closest to the baffle.

Technical Field

The present invention relates to a feed device for a particle separator, and in particular to a feed device for a particle separator containing low and high density particles and/or slurries of various particle sizes. The invention is primarily intended for use as a particle separator for mineral slurries containing low density and/or smaller size particles and high density and/or larger size particles and will be described hereinafter with reference to this application.

Background

The following discussion of the prior art is intended to present the invention in a suitable technical context and to allow its advantages to be properly understood. However, unless explicitly stated to the contrary, reference to any prior art in this specification should not be construed as an explicit or implicit acknowledgement that such art is widely known or forms part of the common general knowledge in the field.

Particle separators are widely used in industry. One type of particle separator is a fluidized bed classifier, which is widely used in the coal and mineral industry to separate particles based on density. The feed slurry enters the fluidized bed classifier and is ultimately separated into a slurry of finer or lower density particles that rise through the vessel and an underflow of larger or higher density particles that are discharged from below. The lower portion of the system is supported by the upward fluidization flow, typically conveyed through the lower base of the vessel.

These classifiers exist in several configurations, the simplest known as an interferential bed separator. The disturbed bed separator essentially comprises a cylinder with a lower bottom shaped like a cone to funnel the material (higher density particles) towards the underflow. A launder is located at the top of the cylinder around the outer rim to collect the overflow containing the low density particles, while a central feedwell is located at the upper part of the cylinder to allow the incoming feed slurry to escape from the fluidization flow to the overflow.

Another configuration is known as a backflow classifier, which includes a plurality of inclined channels above the cylinder, an overflow trough at the top above the inclined channels, including a series of internal flow troughs to deliver overflow to external flow troughs. In a return classifier, the feed slurry is typically fed at an elevation near the lower portion of the inclined channel and is delivered from above or near the inclined channel system.

Another configuration, called an inverted reflux classifier, associated with the reflux classifier consists of an inverted fluidized bed with a plurality of inclined channels located below the cylinder. In this case, the feed slurry enters the wall only through the vertical portion of the system.

Another configuration is known as a gravitational ion, which is actually a back-flow classifier located within the centrifuge. In practice, the vertical axis of the return classifier is rotated by 90 ° so that the axis is located radially of the shaft of the centrifuge.

Each of these particle separation systems requires significant fluidization to support the suspension of the particles to enable separation. This transport of fluidization results in the addition of more fluid, usually water, and therefore more energy. However, it is not possible to reduce the amount of fluidization to reduce energy consumption, since it would adversely affect the suspension of the particles. It also adversely affects two additional functions of fluidization. The first function is to promote de-sliming or cleaning of the material prior to discharge to the underflow. The second function is that the fluidizing fluid provides well-defined and uniform fluidizing conditions to support the weight of the particles in the fluid and thereby prevent mixing with the material fed to the system. This second function is essential to prevent short-circuiting of the slurry and thus preventing misalignment of the slurry.

Disclosure of Invention

According to a first aspect of the present invention, there is provided an apparatus for feeding a feed slurry into a particle separator having a fluidization source, comprising:

a chamber having at least one baffle for dividing the chamber into a first region and a second region, the second region being formed inside the baffle and the first region being formed between an outside of the baffle and the chamber; and

a feed inlet for feeding the slurry to the first zone;

wherein the baffle deflects the slurry away from the second zone and directs fluidizing fluid from the fluidizing source through the second zone to mix with the slurry from the first zone.

Preferably, the feed inlet is arranged to feed the slurry tangentially with respect to the side wall of the chamber.

Preferably, the feed inlet is arranged to feed the slurry so as to induce a rotating flow of the slurry in the first zone.

Preferably, the feed inlet is located adjacent the side wall of the chamber.

Preferably, there are two feed ports located on opposite sides of the chamber sidewall. More preferably, there are four feed ports located at approximately 90 ° intervals around the chamber.

Preferably, a mixing zone is formed in the chamber in which the fluidising fluid from the second zone mixes with the slurry from the first zone. In some embodiments, the mixing region is formed at the discharge end of the chamber. In other embodiments, the mixing region is formed at the upper end of the chamber.

Preferably, the chamber has diverging side walls. More preferably, the side wall diverges from the inlet end of the chamber. Alternatively, the side walls diverge towards the inlet end of the chamber. In one embodiment, the chamber is substantially frustoconical in shape.

In some embodiments, the chamber is substantially cylindrical in shape.

Preferably, the baffle is substantially frusto-conical in shape. Alternatively, the baffle is substantially cylindrical in shape.

Preferably, the baffle is located adjacent the inlet end of the chamber to form a gap between the baffle and the inlet end to allow denser particles to flow through the gap along at least one side wall of the chamber. More preferably, the gap is annular. In some embodiments, the gap has a width ≧ 3 × η, where η is the maximum particle size in the feed slurry.

Preferably, the particle separator is of the type having a plurality of inclined channels. Alternatively, the particle separator is a teeter-totter separator comprising a cylindrical housing with a fluidization chamber arranged below a removal device for removing particles of low density and/or smaller size. In one embodiment, the removal device comprises a flow cell.

A second aspect of the invention provides an apparatus for separating low density and/or smaller size particles from a feed slurry, comprising the apparatus of the first aspect of the invention; a plurality of angled passages located near a first end of the chamber; and a fluidization source for directing a fluidization fluid toward the second region, the fluidization source being located proximate the second end of the chamber.

A third aspect of the invention provides an apparatus for separating low density and/or smaller size particles from a feed slurry, comprising the apparatus of the first aspect of the invention; removing means for removing low density and/or smaller size particles, the removing means being located near the first end of the chamber; and a fluidization source for directing a fluidization fluid toward the second region, the fluidization source being located proximate the second end of the chamber.

Preferably, the fluidization source comprises a fluidization chamber having a fluidized bed to generate a fluidizing fluid from the fluid; a baffle is positioned proximate the second end of the chamber to form a gap between the baffle, the second end, and the fluidization chamber to allow denser particles to flow into the fluidization chamber along at least one sidewall of the chamber.

Preferably, the ratio of the height of the fluidized bed to the diameter of the fluidizing chamber is ≧ 1.

Preferably, the ratio of the combined height of the fluidization chamber and baffle to the fluidization chamber diameter is ≧ 2.

Preferably, the ratio of the height of the device to the diameter of the fluidization chamber is ≧ 3.

Preferably, the fluidising chamber is substantially frusto-conical in shape. Alternatively, the fluidising chamber is substantially cylindrical in shape.

Preferably, the internal diameter of the baffle is substantially the same as the diameter of the fluidization chamber. Alternatively, the internal diameter of the baffle is different from the diameter of the fluidization chamber.

The second and third aspects of the invention may also have the preferred features described in relation to the first aspect of the invention. For example, the gap may have a width of ≧ 3 × η, where η is the maximum particle size in the feed slurry.

A fourth aspect of the invention provides a method for feeding a slurry into a particle separator having a fluidization source, comprising:

dividing a chamber into a first region and a second region by a baffle, the second region being formed inside the baffle and the first region being formed between an outside of the baffle and the chamber;

supplying the slurry to the first zone;

deflecting the slurry away from the second region; and

a fluidizing fluid is directed from a fluidizing source through the second zone to generate a fluidizing stream that mixes with the slurry from the first zone.

Preferably, the method further comprises feeding the slurry tangentially relative to the side wall of the chamber.

Preferably, the method further comprises feeding the slurry so as to induce a rotational flow of the slurry in the first zone.

Preferably, the method further comprises feeding the slurry at opposite sides of the side wall of the chamber.

Preferably, the second region is surrounded by the first region.

Preferably, the method further comprises positioning a baffle adjacent the inlet end of the chamber to form a gap between the baffle and the inlet end to allow denser particles to flow through the gap along at least one sidewall of the chamber.

Preferably, the method further comprises providing the baffle with a substantially cylindrical shape. Alternatively, the method further comprises providing the baffle with a substantially frustoconical shape.

Preferably, the method comprises forming a mixing zone in the chamber in which the fluidised flow from the second zone mixes with the slurry from the first zone. In some embodiments, the method includes forming a mixing zone at the discharge end of the chamber. In other embodiments, the method includes forming a mixing region at an upper end of the chamber.

Preferably, the method further comprises forming the chamber with diverging sidewalls to direct the flow of the denser particles in the chamber. More preferably, the side wall diverges from the inlet end of the chamber. Alternatively, the side walls diverge towards the inlet end of the chamber.

Preferably, the method further comprises allowing the slurry to flow downwardly through a plurality of inclined channels located near the first end of the chamber such that low density and/or smaller sized particles escape from the fluidization flow by being entrained in the inclined channels. And denser and/or larger sized particles in the slurry slide down the channels; low density particles, smaller size particles, denser particles, or larger size particles are removed from the particle separator.

Preferably, the fluidization source includes a fluidization chamber having a fluidized bed to generate the fluidization fluid, and the method further includes positioning a baffle proximate the second end of the chamber to form a gap between the baffle, the second end, and the chamber to allow the denser particles to flow into the fluidization chamber along at least one sidewall of the chamber.

Preferably, the method comprises configuring the fluidising chamber such that the ratio of the height of the fluidised bed to the diameter of the fluidising chamber is ≧ 1.

Preferably, the method includes configuring the fluidization chamber and the baffle such that the ratio of the combined height of the fluidization chamber and the baffle to the diameter of the fluidization chamber is ≧ 2.

Preferably, the method includes configuring the fluidization chamber such that the ratio of the device height to the fluidization chamber diameter is ≧ 3.

Preferably, the method comprises forming the baffle with an inner diameter substantially the same as the diameter of the fluidization chamber. Alternatively, the method includes forming the baffle to have an inner diameter different from a diameter of the fluidization chamber.

Where applicable, the method may also incorporate preferred features of the first, second and third aspects of the invention described above. Again, for example, the method can include providing or configuring the gap to have a width ≧ 3 × η, where η is the maximum particle size in the feed slurry.

Throughout the specification and claims, the words "comprise", "comprising", "comprises", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense, unless the context clearly requires otherwise; that is, in the sense of "including but not limited to (including)".

Furthermore, as used herein and unless otherwise specified the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, merely indicate that different instances of like objects are being referred to, and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

Drawings

Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a cross-sectional view of an apparatus according to one embodiment of the present invention;

FIG. 2 is a schematic diagram of a plan view of the apparatus of FIG. 1;

FIG. 3 is a schematic plan view of another embodiment of the apparatus of FIG. 1;

FIG. 4 is a cross-sectional view of an apparatus according to another embodiment of the invention;

FIG. 5 is a cross-sectional view of an apparatus according to another embodiment of the invention;

FIG. 6 is a cross-sectional view of an apparatus according to yet another embodiment of the invention;

FIG. 7 is a cross-sectional view of an apparatus according to another embodiment of the invention;

FIG. 8 is a cross-sectional view of an apparatus according to another embodiment of the invention;

FIG. 9 is a cross-sectional view of a portion of an apparatus according to yet another embodiment of the invention;

FIG. 10 is a plan view of the device of FIG. 9;

FIG. 11 is a plan view of an alternative to the device of FIG. 9;

FIG. 12 is a cross-sectional view of an apparatus according to other embodiments of the invention; and

fig. 13 is a cross-sectional view of a device according to yet another embodiment of the invention.

Detailed Description

The invention will now be described with reference to the following examples, which are to be considered in all respects as illustrative and not restrictive. In the drawings, identical features in the same embodiment or corresponding features common to different embodiments have been given the same reference numerals.

Reference is generally made to flowing denser particles to the underflow and less dense particles to the overflow. However, those skilled in the art will appreciate that rather fine dense particles will flow to the overflow, while oversized lower density particles will flow to the underflow. More generally, faster settling particles flow to the underflow and slower settling particles flow to the overflow, but in many separators the system geometry and the state of the suspension can also affect the result. Under relatively dilute conditions, coarser (larger size) particles tend to flow to the underflow and finer (smaller size) particles to the overflow. It is clear that the response of a system involving particles having a size and density distribution is complex. Thus, for purposes of describing embodiments of the invention, reference to a denser or larger size particle (e.g., faster settling) flow to underflow and a less dense or smaller particle flow to overflow has been made in its entirety to apply the simpler description. This simpler description should not be considered to limit the application of the invention in any way.

Referring to fig. 1, a particle separator 1 is shown comprising a fluidization source 2, a plurality of inclined channels 3 and means 4 for feeding slurry S into the particle separator according to one embodiment of the present invention. In this embodiment, the particle separator 1 is configured to function as a backflow classifier. Thus, the inclined channel 3 is located in the upper part 5 of the particle separator 1 and the fluidization source 2 is located in the lower part 6. The inclined channel 3 is formed by a series of inclined plates 7. A launder 8 is located at the top of the chamber 5 for receiving and removing an overflow 9 of low density and/or smaller size particles, which overflow 9 is displaced upwards by the action of an upward fluidisation flow 10 from the fluidisation source 2. The fluidization source 2 includes a distributor 12 formed in the lower portion 6 at the bottom of the fluidization chamber 13. The distributor 12 forms a fluidized bed which directs the fluidization flow 10 upwards in the particle separator 1. An outlet 15 in the lower part 6 discharges an underflow 16 of denser particles.

The feeding device 4 comprises a chamber 17 which is divided into an outer zone 20 and an inner zone 21 by a baffle 22. Two feed openings 23 for feeding slurry S into the outer zone 20 are located on opposite sides 24 of the chamber 17, with conduits 25 for conveying the slurry, as best shown in fig. 2. The baffle 22 in this embodiment comprises a substantially cylindrical pipe or conduit located near the lower end 26 of the chamber 17 and mounted to a side wall 27 of the chamber 17 by a support member 28 near the top of the baffle 22. The chamber 17 has a conical portion 17a connected to the fluidization chamber 13 and a cylindrical portion 17b connected to the upper part 5 of the particle separator. The cylindrical portion 17b thus forms the discharge end of the feed device 4. The tapered portion 17a of the chamber 17 extends downwardly with a steep side wall 27 to ensure that denser particles are easily transported downwardly rather than adhering to the side wall.

The fluidising chamber 13 can be seen as essentially a cylinder of much smaller diameter which intersects the conical portion 17a of the chamber 17. The smaller diameter helps to provide a suitable ratio of fluidized bed height to diameter which facilitates a more uniform movement of material within the fluidization region F formed within the particle separator. Smaller diameters require less fluidizing water and therefore fewer fluidizing nozzles to install or maintain. The total fluid flow to the system overflow 9 is therefore lower, and it is therefore easier to prevent fine particles from reaching the overflow. The ratio of the height of the fluidized bed (defined by the height of the fluidizing chamber 13) to the diameter is preferably equal to or greater than 1. It is also preferred that the length of the baffles is equal to the height of the fluidization chamber 13. Thus, it is preferred that the combined height to diameter ratio of the fluidization chamber 13 and the baffle 22 is greater than 2. It is also preferred that the space above the baffle 22 has the same height as the fluidizing chamber 13. These preferred ratios are shown in fig. 1 (although the figure is not to scale), where the height of the fluidization chamber 13, the baffle 22, the space above the baffle 22, respectively, are the same and are indicated by distance H, while the diameter of the fluidization chamber 13 is indicated by distance D. Thus, the ratio of the height to the diameter of the fluidized bed is H/D.gtoreq.1, the ratio of the combined height to the diameter of the fluidizing chamber 13 and the baffle 22 is 2H/D.gtoreq.2, and the ratio of the height Z to the diameter of the entire feed device 4 is 3H/D.gtoreq.3.

The transfer of material (denser particles) through the outlet 15 to the underflow 16 has a number of beneficial effects when the diameter of the fluidisation zone is small. First, if the solids flow to the underflow 16 is relatively small compared to the flow of the feed slurry S, it is therefore easier to establish a high density particle bed in a small area. This effect is applicable to low grade sand feeds where the underflow solids rate is low. Thus, a net flow 10 of fluidizing water will still pass upwardly through the bed, providing a high quality desliming. Desliming can also be achieved at lower fluidization flow rates, so that the ultra-fine heavy minerals (denser particles) are less likely to flow to the overflow 9. Where the feed slurry S requires a higher proportion of material to be discharged to the underflow 16, the diameter of the cylindrical fluidisation zone F is simply increased by increasing the diameter of the fluidisation chamber 13. Thus, the design of the fluidization chamber may be adapted to any specific purpose.

The feed slurry S enters the chamber 17 at a feed inlet 23 just above the intersection between the conical portion 17a and the fluidising chamber 13. In this embodiment, the feed slurry S desirably enters the sidewall 27 tangentially, creating a rotating flow 30, as best shown in FIG. 2. The rotating flow 30 tends to transport the larger and denser particles down and along the wall toward the lower end 24. In this way, the energy of the incoming feed slurry S is used to provide some of the energy needed to support the suspension of particles in the particle separator 1. In other embodiments, the feed slurry S enters the sidewall 27 tangentially at up to four locations 90 ° apart in a manner that facilitates the creation of a rotating flow in one direction, as best shown in fig. 3. In another embodiment, additional tangential entry points are used to convey the feed. In further embodiments, the tangential entry points are not in the same horizontal plane, but may be located at different heights of the chamber 17.

The baffle 22 is positioned such that a gap 40 is formed between the baffle and the lower end 24 of the chamber 17. Due to the cylindrical shape of the baffle 22, the gap 40 has a circular or annular shape between the baffle and the fluidization chamber 13. It should be understood that where the baffle 22 has a different shape (e.g., conical or inverted conical), the gap 40 will also have a different shape. The more descending and denser particles from the rotating flow 30 pass through the gap 40 into the fluidization chamber 13. The gap 40 can be made wider as needed to prevent possible clogging. In general, the gap 40 must be larger than the largest possible particle size fed into the particle separator 1, and preferably 3 times or more larger than this size. That is, if the maximum particle size is specified as η, the gap 40 should be ≧ 3 × η. Also, oversize protection is typically applied to the feed slurry before the particle separator 1. In some embodiments, if clogging of the gap 40 is expected, additional water or fluid is injected into the vicinity. The horizontal support members 28 may also be doubled as conduits to deliver additional fluidizing water, if desired. This means that the effective height to diameter ratio becomes more favourable for fluidization.

The positioning of the cylindrical baffle 22 adjacent to the fluidization chamber 13 means that the baffle 22 effectively extends the height of the cylindrical fluidization region F in the fluidization chamber 13, as the fluidization flow 10 flows upwardly through the fluidization region F into and through the inner region 21 of the baffle 22. The inner diameter of the baffle 22 being substantially the same or equal to the diameter of the fluidization chamber 13 contributes in part to extending the fluidization region F into the inner region 21. In some embodiments, the inner diameter of the baffle 22 need not be the same as the diameter of the fluidization chamber 13. For example, the baffle 22 may have a conical configuration with an inner diameter that is initially the same or nearly the same as the diameter of the fluidization chamber 13, and then gradually increases in diameter. Likewise, the baffles 22 may have an inverted cone-shaped configuration in which their inner diameter is initially the same or nearly the same as the diameter of the fluidization chamber 13, and then gradually decreases in diameter. Finally, the baffles may have a smaller and/or larger inner diameter relative to the diameter of the fluidization chamber 13. However, it is generally preferred that the internal diameter of the baffle 22 is substantially equal or equal to the diameter of the fluidising chamber 13.

The cylindrical baffle 22, also similar to a submerged entry feedwell, helps to distribute the majority of the incoming feed slurry S outside the baffle, deflecting the slurry S upward and away from the vicinity of the cylindrical fluidization region 13. It is apparent that relatively larger or higher density particles will have a tendency to slide or flow downwardly along the sidewall 27 through the gap 40 between the cylindrical baffle 22 and the cylindrical fluidization region F. This movement prevents potential clogging and is desirable because the material is likely to have a tendency to be added to the underflow 16.

However, once located within the fluidization chamber 13, depending on the system fluid dynamics, these particles will be disposed downwardly to the underflow 16 or displaced upwardly and out of the fluidization region F. The volumetric flow rate of this material, which is composed of larger and denser particles, will be small compared to the flow of the entire feed slurry S. Thus, the material does not adversely interfere with the uniform fluidization regime in the fluidization chamber 13.

Thus, in operation, a substantial portion of the total feed slurry S will rotate around the outer wall of the cylindrical baffle 22 along the rotating flow 30 in the chamber 17 while tending to flow upwardly. The fluidization flow from the inner zone 21 of the baffle 22 is preferably mixed with the slurry S from the outer zone 20 in a mixing zone 42. In this embodiment, the mixing zone 42 is located at an upper region or end of the chamber 17, adjacent the cylindrical portion 17b corresponding to the discharge end. The energy of the incoming feed slurry S contributes to the transport and, importantly, supports the majority of the slurry that is suspended above in the conical portion 17 a. Thus, there is little or no tendency for the slurry material to settle and adhere to the sidewalls 27 of the tapered portion 17 a. Thus, there is no need to provide separate fluidizing water in the chamber 17 to suspend the slurry S at this radial distance from the center of the particle separator 1. However, limited water volume injection may be used to assist with the rare likelihood of plugging. Thus, the energy of the feed slurry S and its volumetric flow rate serve to support the suspension in the outer zone 20 in the conical portion 17 a.

Finally, the feed slurry flow is directed upwards through the conical portion 17 and then through the cylindrical portion 17b of the chamber 17 towards the system of inclined channels 3, in particular in the outer radial region of the separator 1, thereby providing better and more uniform support across all inclined channels. This benefit resulting from this embodiment of the invention is in contrast to the usual way of operating a reflux classifier, where the feed enters from a position directly below the inclined channel downwards, is forced to reverse by the fluidisation flow, and then passes upwards through the inclined channel. In this case of the conventional backflow classifier, the upward flow through the inclined channel is more concentrated in the center, and thus the distribution of the material in the inclined channel is not uniform. Thus, in this embodiment of the invention, the inclined channels and hence the particle separator 1 are used more efficiently.

Another advantage of the described configuration is that it also saves space in some cases by feeding the feed slurry S into the chamber 17 near the lower end 26. Thus, the upper part or section 5 of the particle separator 1 can be used to deploy the inclined channel 3 and the launder 8 more efficiently without compromising the design of the upper part or section 5.

Furthermore, the solids (i.e. denser particles) returning from the inclined channel 3 will move downwards along the side wall 27 towards the fluidising chamber 13. Those solids that are located above the cylindrical fluidization region F tend to be transported into the cylindrical fluidization region F because the upward flow velocity is lower than elsewhere. Those solids outside the fluidization region F are remixed with the feed slurry S and increase in concentration. This means that solids tending to flow back in the particle separator 1 increase their concentration to the level required for their transport to the cylindrical fluidization region F of the fluidization chamber 13.

It will be appreciated that there are many possible variations that can be applied to this design, as shown in figures 4 to 11, which are not to scale, but are intended to prefer that the bed height to diameter ratio H/D ≧ 1, the total height to diameter ratio of the fluidising chamber 13 and baffle 22 is 2H/D ≧ 2, and the height to diameter ratio Z of the entire feed device 4 is 3H/D ≧ 3. For example, the cylindrical baffle 22 may be replaced with a conical baffle 45 (as best shown in fig. 4 and 7), an inverted conical baffle 48 (as best shown in fig. 8), or a partially conical and partially cylindrical baffle 49 (as best shown in fig. 6). In another example, the cylindrical fluidization chamber 13 may also be replaced with a conical chamber 50 (best shown in FIG. 5), a conical chamber 52 (best shown in FIG. 6). Yet another example changes the feeder device chamber from a frustoconical shape to a purely conical shape 55 (as best shown in fig. 7), a cylindrical shape 58 (as best shown in fig. 4), or an inverted conical shape 60 (as best shown in fig. 6). In another example, the conical shape is in all cases replaced by a straight inverted pyramid or similar polyhedral geometry.

In fig. 9, a simplified schematic diagram shows a chamber 61 having an opening or aperture 62 in its inner surface 63 to form a fluidized bed from a fluidizing fluid, wherein the fluidizing fluid flows from a fluid source 66 into a region 64 between the inner surface 63 and an outer surface 65. An underflow discharge conduit in the form of a conduit 67 is provided with a control valve 68. The control valve 68 is preferably connected to receive signals from two pressure sensors (not shown). If the measured suspension density exceeds a set point or value, the control valve 68 is opened, and below or at the set point, the control valve 68 is closed. In this way, denser and/or larger sized particles are easily and conveniently removed from the apparatus 4. Figures 10 and 11 show two versions of the device of figure 9. Fig. 10 shows a top or plan view of the chamber 61, wherein the chamber has a conical shape such that the opening 62 is formed in the inner surface 63 of the cone. Fig. 11 shows a top or plan view of the chamber 61, wherein the chamber has an inverted pyramid shape such that the opening 62 is formed in the inner surface 63 of the inverted pyramid defined by four connected oblique portion-triangular plates 69.

One advantage of the conical fluidization chambers 50, 52 (and thus the conical fluidization regions) is that the effective fluidization velocity at the base is higher, allowing coarser particles to be suspended while providing a lower fluidization velocity at higher elevations. This forces more fine particles to the underflow 16. A similar effect can be achieved by using conical baffles 45, 48, which reduce the velocity in the upper region and provide an inclined surface to support the particles settling towards the underflow. In each of these variations in the shape of the chamber 17, the baffle 22 and the fluidising chamber 13, the feed device 4 will still operate in substantially the same manner as described in relation to figures 1 and 2.

In some embodiments, the feedwell 23 and conduit 25 are modified to create a cyclone-like feed arrangement with a higher feedwell pressure to achieve stronger centrifugal forces. In other embodiments, there is only one feed opening 23. In other embodiments, the feed conduit 25 is angled from the central axis of the chamber 17, thereby creating an upwardly directed rotational flow, as best shown in fig. 4 and 8.

Referring to FIG. 12, another embodiment of the present invention is shown, but not drawn to scale, in which a particle separator is configured as a gravity ion or centrifuge 70 having a plurality of radial arms 72 mounted to a central rotating shaft 75. An assembly 76 is mounted at the end of each radial arm and comprises an inclined channel 3, a fluidization source 2 and a feeding device 4. In this embodiment, the assembly 76 can advantageously incorporate the fluidization region F within a relatively small space within the assembly 76. Due to the arrangement of the feed device 4, as much space as possible is occupied by the inclined channel system 3. The feed device 4 in the attractor 70 greatly reduces the amount of fluidizing water W required and also improves the height to diameter ratio of the fluidizing zone F, thus producing a more uniform fluidizing zone and hence better de-sludging quality. Thus, the total length of the fluidizing zone F (including the inner region 21 of the baffle 22) leading to the inclined channel 3 can be shorter. In addition, the high feed flow rate helps prevent feed solids from adhering to the inner surface of the attractor 70 where the centrifugal force 77 is high, since a reduced fluidization flow rate means that the fluidization velocity (and thus the centrifugal force) is low.

Referring to fig. 13, there is shown another embodiment of the invention, not to scale, in which the particle separator is configured as an inverted refluence flotation tank 90. In this embodiment the outer region 20 of the baffle 22 becomes the disengagement zone 91 to allow denser particles in the form of tailings to flow downwardly towards the inclined channel 3 whilst allowing the externally generated bubble mixture to rise upwardly and enter the inner region 21 of the baffle 22 and then the cylindrical fluidising zone F. In this manner, the bubbles in the bubble mixture are not affected by the turbulence created by the large entry of the feed slurry S into the outer zone 20 through the inlet 23 in the inner zone 21, reducing the tendency of the larger particles to force the removal of foam. In some embodiments, the cylindrical baffle 22 may extend further down towards the inclined channel 3 or even close to the inclined channel 3. This arrangement is more likely to cause the inclined channel 3 to partially overflow, forcing the bubble region into the inclined channel 3. This brings important benefits as it creates a stable and self-controlled interface between the gas bubble mixture and the tailings. Furthermore, a higher height to diameter ratio should lead to better downward fluidization and thus to a desliming of the product overflow 9.

Although the embodiment of fig. 1 has a mixing zone 42 at the upper end of the chamber 17, it should be noted that in the embodiment of fig. 12 and 13, the mixing zone 42 is not at the upper end of the chamber. Instead, the mixing zone 42 is located at the discharge end of the chamber 17 adjacent to the inclined channel 3 (on the side of the attractor 70 in fig. 12 and in the middle of the reverse flow flotation cell 90 in fig. 13).

The present invention may also be used with other types of flotation-based particle separators, such as inverted reflux classifiers. In the case of an inverted return classifier, the same technical benefits of a return flotation cell are achieved for a reverse flow classifier using the feed device of the embodiment of fig. 12, since an inverted return classifier is typically used to process particles less dense than the fluid, thereby separating them from denser particles.

It should also be understood that any of the features of the preferred embodiments of the present invention may be combined together and not necessarily applied in isolation from each other. For example, the feature of baffles having a conical shape as shown in fig. 4 may be used in the gravity cell 70 of fig. 9 or the inverted flotation cell 90 of fig. 12. Likewise, any of the configurations shown in fig. 5-8 may also be used for the attractor 70 of fig. 9 or the reverse flotation cell 90 of fig. 12. A similar combination of two or more features from the above-described embodiments or preferred forms of the invention may be readily made by those skilled in the art.

By providing a feed device for slurry into a particle separator, wherein a baffle divides the chamber into two regions, the present invention enables the energy of the incoming feed slurry to suspend particles in the particle separator, thereby reducing the need for additional fluidization fluid or higher fluidization fluid flow rates and ensuring a more uniform particle distribution over the inclined channel. In addition, the present invention makes the fluidization region more efficient, again reducing the need for fluidization fluid. In addition, the baffles advantageously facilitate efficient use of the fluidizing fluid to efficiently separate low density and/or smaller sized particles from the slurry. All of these advantages of the present invention result in a feed device that is suitable for use with a variety of particle separators and allows the particle separator to more efficiently separate particles of low density and/or smaller size from the slurry, more efficiently use energy and consume less water/fluid for fluidization, while allowing more water and solids feed. Furthermore, the present invention can potentially be retrofitted to existing particle separators. In all of these respects, the present invention represents a practical and commercially significant improvement over the prior art.

Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.