TECHNICAL FIELD

[0001] The present subject matter relates to dispersing apparatus for bulk materials, and particularly apparatus to provide even dispersing of pulverous bulk materials.

BACKGROUND

[0002] In many industrial operations streams of bulk materials are split into two or more courses. For example, in flash smelting furnaces, the feed material is usually directed into the burner through two or more inlets spaced around the circumference of the upper portion of the burner. Uneven distribution of the feed material in the burner adversely affects performance. The feed material passes from air slides or drag chains through a splitter box that separates the charge into the separate feed streams. However, the material division with splitter boxes can be unsatisfactory. Air slides, for example, typically carry more material toward the center of the flow. As a result, the splitter box outlets that receive feed from the center of the flow tend to receive more of the charge material than those that are feed by the outer sections of the flow.

[0003] Furnace operations also often use drag chain conveyors to carry the charge material. Drag chain conveyors have a tendency to introduce pulsation to the flow of the charge. The material forms small piles in front of each of the drag chain bars or flights and as the small piles drop out of the drag chain, they create surges in flow.

SUMMARY

[0004] The following summary is intended to introduce the reader to the more detailed description that follows, and not to define or limit the claimed subject matter.

[0005] According to one aspect, a dispersing apparatus for bulk material is provided. The dispersing apparatus includes an accumulator, at least one inlet to receive material into the accumulator, and at least one outlet that evenly disperses material out of the apparatus. The accumulator has at least one variable aperture, the aperture being normally biased to a more closed position. The apparatus also includes an aperture control assembly that opens the aperture, responsive to a build- up of material in the accumulator, so as to increase the flow of material out of the accumulator.

[0006] In some examples, the aperture control assembly includes a barrier that closes the aperture. The aperture may be located in the lower portion of the accumulator with the barrier moving downwardly to open the aperture. According to some embodiments, the aperture control assembly is responsive to the weight of material in the accumulator. The aperture control assembly may include an urging mechanism that acts upwardly on the barrier, for example, by means of a spring.

[0007] In some examples, the apparatus also includes a discharge hopper that receives material from the accumulator when the aperture is open. The discharge hopper may have partitions that define a plurality of compartments that each lead to a separate outlet. The barrier may also be provided with fins that define discharge sectors, with the fins being generally aligned with the partitions of the discharge hopper.

[0008] In some embodiments, the accumulator is generally cylindrical and the barrier is a conical plug mounted concentrically within the accumulator, held by a suspension rod that can permit the plug to move vertically. The suspension rod may be suspended by a spring that biases the plug against the lower edge of the accumulator and that allows the plug to move downwardly in response to the weight of material built up in the accumulator. Alternatively, the plug can be supported from underneath by a spring that similarly biases the plug against the lower edge of the accumulator but allows the plug to move downwardly in response to the weight of material built up in the accumulator.

[0009] In other embodiments, the accumulator is generally cuboid and the barrier is a pyramidal plug.

[0010] In other examples, the accumulator has a plurality of apertures, each having a barrier. The barriers may pivot to open the apertures, and each of the barriers may be mounted to a common mounting.

[0011] In some examples the aperture control assembly is incorporated into a flash furnace concentrate burner feed chute. The aperture is formed at the interface of the dispersion cone and the feed chute. The lance to which the dispersion cone is mounted moves vertically and is suspended on a spring or actuator from the top of the feed chute. The feed chute is constructed to have sufficient volume to function as the accumulator.

BRIEF DESCRIPTION OF DRAWINGS

[0012] In order that the claimed subject matter may be more fully understood, reference will be made to the accompanying drawings, in which:

[0013] Figure 1 is an isometric view of a dispersing apparatus according to one embodiment, with internal structure shown in stippled lines.

[0014] Figure 2 is an exploded isometric view of the same apparatus.

[0015] Figure 3 is an exploded isometric view of the same apparatus, seen from a higher perspective.

[0016] Figure 4 is a cross sectional side view of the same apparatus, shown in its closed position.

[0017] Figure 5 is a cross sectional side view of the same apparatus, shown in a partially opened position.

[0018] Figure 6 is an isometric view of a dispersing apparatus installed to feed a flash smelter.

[0019] Figure 7 is a cross sectional view of a dispersing apparatus according to a second embodiment.

[0020] Figure 8 is a schematic cross sectional view of a dispersing apparatus according to another embodiment.

[0021] Figure 9 is a schematic cross sectional view of a dispersing apparatus according to another embodiment.

[0022] Figure 10 is a schematic cross sectional view of a dispersing apparatus according to another embodiment.

[0023] Figure 11 is a schematic isometric view of a dispersing apparatus of another embodiment.

[0024] Figure 12 is a schematic isometric view of a dispersing apparatus of another embodiment. [0025] Figure 13 is a schematic cross sectional view of a dispersing apparatus of another embodiment.

[0026] Figure 14 is a schematic cross sectional view of a dispersing apparatus of another embodiment.

[0027] Figure 15 is a schematic cross sectional view of a dispersing apparatus of another embodiment.

[0028] Figure 16 is a schematic cross sectional view of a dispersing apparatus of another embodiment.

[0029] Figure 17 is a schematic cross sectional view of a dispersing apparatus of another embodiment.

[0030] Figure 18 is a schematic cross sectional view of a concentrate burner incorporating a dispersing apparatus according to one embodiment.

[0031] Figure 19 is a close-up cross sectional view of the lance tip portion of the concentrate burner of Figure 18.

DETAILED DESCRIPTION OF EMBODIMENTS

[0032] In the following description, specific details are set out to provide examples of the claimed subject matter. However, the embodiments described below are not intended to define or limit the claimed subject matter. It will be apparent to those skilled in the art that many variations of the specific embodiments may be possible within the scope of the claimed subject matter.

[0033] As shown in Figs. 1-6, the dispersing apparatus 20 includes a cylindrical accumulator 21 which is mounted to a discharge hopper 26 that feeds four outlets 29. The cylindrical accumulator 21 has an inlet 25 near its upper end which allows feed material to fall into the accumulator 21. A conical plug 41 is positioned below the accumulator 21 held by a suspension rod 45 that extends through the accumulator 21 and through its top cover 39. The suspension rod 45 is connected via a nut 48 to a support spring 47. The spring 47 is sized so that it keeps the lower end 23 of the accumulator 21 closed by providing a sufficient upward force on the conical plug 41 when there is no material in the accumulator 21 , or when there is only a small amount of material. [0034] As the material builds-up on the conical plug 41 , the weight of the material eventually provides enough downward force on the plug 41 to begin compressing the spring 47. The spring 47 is sized so that the conical plug 41 begins to move downwardly when the build-up of material within the accumulator 21 has completely covered the plug 41 and is partly up the accumulator 21. As the plug 41 moves downwardly, it opens an annular aperture 46 between the upper face 43 of the plug 41 and the lower edge 44 of the accumulator 21. Opening the aperture 46 allows the material to flow downwardly into the discharge hopper 26.

[0035] The discharge hopper 26 has partitions 27 and the plug 41 has vertical fins 42 that align with the partitions 27 of the discharge hopper 26. The downward flow material is thus directed to four separate compartments within the discharge hopper 26 that lead to the four outlets 29. The fins 42 on the conical plug 41 also help to maintain the plug 41 concentric within the accumulator 21. This ensures that the aperture 46 created as the plug 41 moves downwardly is of a constant dimension around the circumference of the lower edge 44 of the accumulator 21. An anti- rotation device, can be used to prevent rotation of the plug 41.

[0036] When the plug 41 has moved downwardly only a small amount, the flow of material through the inlet 25 may still be greater than the flow through the outlets 29 and the level of material in the accumulator 21 will continue to rise. This will add more weight on the upper face 43 of the plug 41 , compressing the spring 47 more and thereby allowing the conical plug 41 to move downwardly further. Eventually, the apparatus will reach a steady state condition where the inlet flow is equal to the outlet flow. The level of material in the accumulator 21 when the apparatus reaches steady state will depend on the sizing and the tensioning of the spring 47. A dashpot 51 is mounted to the cover 39 of the accumulator 21 in parallel with the spring 47 to dampen excessive up and down movement of the plug 41.

[0037] The cover 39 mounts to the upper end 22 of the accumulator 21 by being bolted to an upper flange 37 on the accumulator 21. The accumulator 21 also has a lower flange 31 which rests on an upper ring 32 of the discharge hopper and is held in place by means of studs 33 that extend upwardly from the ring 32 through holes in the lower flange 31. Braces 35 maintain the accumulator 21 upright to the lower flange 31. The apparatus can be disassembled for transport and for maintenance.

[0038] It will be noted that the apparatus is not sensitive to having the material build up concentrically in the accumulator. It will, however, of course be appreciated that having two or more inlets would provide the advantage of redundant feed supplies. The apparatus is apt for supply from one or more drag chain conveyors or air slides, but it can be adapted to other sources of supply.

[0039] The apparatus is useful in de-air rating the material as it builds up in the accumulator, thereby reducing the tendency of a material to fluidize.

[0040] It will be appreciated by those skilled in the art that many variations would be possible. For example, a load cell or other gauge connected to the plug could be used to weigh the amount of material built up in the accumulator. Alternatively, a photo cell or other sensor could be used to measure the height of the material. An actuator could then be used to control the position of the plug and thereby open the aperture, rather than relying on the spring, the actuator being responsive to a control signal dependent on the weight gauge or height sensor.

[0041] A manual bypass could be included that would permit an operator to push down on the suspension rod and thereby compress the spring and open the aperture to release a blockage. An automatic bypass mechanism could also be incorporated that would be activated if the build up of material in the accumulator became too high, pushing down on the plug to release extra material. The accumulator could also have an internal screen to break up large pieces.

[0042] As shown in Fig. 6, the present dispersing apparatus can be used to provide four even feed streams to the burner of a flash smelting furnace.

[0043] As shown in Fig. 7, the accumulator could have inclined sides like a funnel, and the inlet could be on the top of the accumulator.

[0044] As shown in Fig. 8, the vertical fins on the conical stopper could be removed. However, other means would be required to maintain the plug concentric within the accumulator, such as a slip tube.

[0045] As shown in Fig. 9, the spring and damper could be located below the conical plug. The central rod could still be used for alignment, or the rod could be omitted altogether with other means substituted for maintaining the plug concentric within the accumulator.

[0046] As shown in Fig. 10, the accumulator could be cuboid with the plug being pyramidal shape. Other shapes for the accumulator and the stopper are also possible.

[0047] As shown in Fig. 11 , the accumulator could have a plurality of apertures, for example, openings having corresponding release flaps all connected by a common linkage so that they open and release in unison.

[0048] As shown in Fig. 12, the accumulator could provide a continuous annular outlet rather than having the material separated into a plurality of outlets.

[0049] As shown in Fig. 13, the outlet aperture can be made larger than the accumulator with guide fins used on the interior of the accumulator or the larger opening.

[0050] As shown in Fig. 14, the guide fins can be made larger than the conical plug to improve concentricity.

[0051] As shown in Fig. 15, the outlet of the accumulator can be made to have a conical shape smaller than the outlet aperture, with guide fins provided on the outer opening.

[0052] As shown in Fig. 16 and 17, the shape of the plug can have a convex or concave surface.

[0053] Turning to Figs 18 and 19, when a dispersion device 120 is incorporated into a concentrate burner 201 , the dispersion cone 141 and feed chute 121 forms the aperture of the assembly. The dispersion cone 141 must be so designed that it forms a sealing surface with the feed chute 121. The lance 200, to which the dispersion cone 141 is mounted protrudes through the top of the feed chute, where it can be mounted via a threaded connection or flange to a spring or linear actuator with a load sensor. The lance 200 is thus able to travel vertically in response to build-up of concentrate in the feed chute 121 , increasing the size of the aperture when feed accumulates and decreasing the size of the aperture when the level of feed in the chute 121 is reduced. The spring is sized so that it keeps the lower end of the feed chute 121 closed by providing a sufficient upward force on the lance 200 when there is no material in the feed chute 121 , or when there is only a small amount of material. The chute 121 is sized to provide sufficient volume so as to always maintain coverage over the dispersion cone 141. This should typically be between 5 - 30s worth of feed at the design throughput of the burner.