FLAT-WIRE BELT CONVEYORS

Abstract

Separation units for dewatering slurries such as flat-wire belt conveyors are disclosed. In some embodiments, the separation unit includes a tension pulley for maintaining tension in the flat-wire conveyor belt. The flat-wire conveyor belt is looped around the head pulley, tail pulley and tension pulley. In some embodiments, the head pulley and/or tail pulley include teeth for removing material from the mesh openings of the flat-wire belt conveyor.

Claims

1. A separation unit for dewatering a slurry comprising: a conveyor belt having mesh openings to separate material in the slurry; a head pulley; a tail pulley; and a tension pulley for maintaining tension in the flat-wire conveyor belt, the conveyor belt being looped around the head pulley, tail pulley and tension pulley.

2. The separation unit as set forth in claim 1 comprising a floor to carry liquid and any solids that passes through the conveyor belt toward a separation unit liquid outlet, the separation unit having a pivot axis about which the floor and tension pulley may pivot to allow the tension pulley and floor to rise and fall with changes in belt loading and/or length.

3. The separation unit as set forth in claim 1 comprising deflectors to turn solids on a top course of the belt.

4. The separation unit as set forth in claim 1 wherein the tail pulley comprises teeth that protrude through the belt mesh openings during rotation of the belt to push material through the mesh openings.

5. The separation unit as set forth in claim 4 wherein the teeth are arranged in rows, the teeth in each row being circumferentially staggered.

6. The separation unit as set forth in claim 5 wherein each tooth is staggered from adjacent teeth in the row.

7. The separation unit as set forth in claim 1 wherein the separation unit is angled upward from the tail pulley toward the head pulley.

8. The separation unit as set forth in claim 1 wherein the belt is a flat wire belt conveyor that includes bands that form the mesh openings.

9. A separation unit for dewatering a slurry comprising: a head pulley; a tail pulley; and a flat-wire conveyor belt having mesh openings to remove solids from the slurry, the flat-wire conveyor belt being looped around the head pulley and tail pulley, the head pulley and/or tail pulley having teeth arranged in rows to push material through the mesh openings, the teeth in each row being circumferentially staggered.

10. The separation unit as set forth in claim 9 wherein the tail pulley has teeth arranged in rows, the teeth in each row being circumferentially staggered.

11. The separation unit as set forth in claim 10 wherein each tooth is staggered from adjacent teeth in the row.

12. The separation unit as set forth in claim 9 wherein each tooth is staggered from adjacent teeth in the row.

13. The separation unit as set forth in claim 9 comprising a floor to carry liquid and an solids that pass through the flat-wire conveyor belt toward a separation unit liquid outlet.

14. The separation unit as set forth in claim 9 comprising deflectors to turn solids on a top course of the belt.

15. The separation unit as set forth in claim 9 wherein the teeth are arranged in rows, the teeth of each row comprising a first set of teeth and a second set of teeth circumferentially offset from the first set of teeth.

16. The separation unit as set forth in claim 9 wherein the belt includes bands that form the mesh openings.

17. The separation unit as set forth in claim 16 wherein the bands are connected to rods.

18. The separation unit as set forth in claim 17 wherein the bands undulate such that each row of openings comprises a first set of openings and a second set of openings, the first and second set of openings having circumferentially offset centerlines.

19. The separation unit as set forth in claim 18 wherein the teeth are arranged in rows, the teeth of each row comprising a first set of teeth and a second set of teeth circumferentially offset from the first set of teeth.

20. The separation unit as set forth in claim 19 wherein a width of the offset of the centerlines of the openings is equal to the width of the offset of the teeth.

21. A separation unit for dewatering a slurry comprising: a head pulley; a tail pulley; and a flat-wire conveyor belt having mesh openings to separate a liquid fraction from a solid fraction in the slurry, the flat-wire conveyor belt being looped around the head pulley and tail pulley, the head pulley and/or tail pulley having teeth, the teeth being arranged to extend through at least 50% of the openings along a width of the flat-wire conveyor belt.

22. The separation unit as set forth in claim 21 wherein the tail pulley has teeth, the teeth being arranged to extend through at least 50% of the openings along a width of the flat-wire conveyor belt.

23. The separation unit as set forth in claim 21 wherein the teeth extend through at least 75% of the openings along a width of the flat-wire conveyor belt.

24. The separation unit as set forth in claim 21 wherein the teeth extend through at least 90% of the openings along a width of the flat-wire conveyor belt.

25. The separation unit as set forth in claim 21 wherein the teeth extend through each opening along a width of the flat-wire conveyor belt.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG. 1 is a perspective view of a separation unit for dewatering slurry;

[0010] FIG. 2 is a detailed perspective cross-section view of the separation unit showing a tail pulley and a tension pulley;

[0011] FIG. 3 is a cross-section view of the separation unit;

[0012] FIG. 4 is a perspective cross-section view of the separation unit with the belt not shown;

[0013] FIG. 5 is a bottom view of the separation unit with the belt not shown;

[0014] FIG. 6 is a perspective view of the tail pulley of the separation unit;

[0015] FIG. 7 is a detailed perspective view of an embodiment of the separation unit showing the belt and tail pulley; and

[0016] FIG. 8 is a perspective view of the tail pulley of FIG. 7.

[0017] Corresponding reference characters indicate corresponding parts throughout the drawings.

DETAILED DESCRIPTION

[0018] A separation unit 25 for dewatering slurries such as an earthen slurry having a liquid fraction and a solid fraction is shown in FIG. 1. In accordance with embodiments of the present disclosure, the separation unit 25 is a flat-wire belt conveyor having mesh openings 80 (FIG. 7). Such flat-wire belt conveyors may include spaced wires or bands which form an open mesh in the belt that allow for liquids and particles that fit through the mesh openings to pass through the mesh. In various embodiments, the mesh size of the belt may be from about 0.25 cm to about 5 cm or from about 0.5 cm to about 3 cm. Liquid and small solids that pass through the mesh fall through the top course 53a (FIG. 2) of the belt, land on the bottom course 53b of mesh (i.e., the return) and fall through the bottom course of mesh onto a conveyor floor or chute 58. The belt 53 may rest on the conveyor floor 58 and scrape material toward the liquid discharge end 61 of the separation unit 25. Solids that do not pass through the openings are carried forward by the belt to solids outlet 76 (FIG. 1). While the belt 53 is shown as being a solid belt in FIGS. 1-5 for simplicity, it should be understood that the belt 53 includes mesh openings throughout the top course 53a and bottom course 53b.

[0019] In some embodiments in which the separation unit 25 is a flat-wire belt conveyor, the conveyor includes a series of deflectors 55 (FIG. 1) that act to turn or otherwise redirect solids that are moving forward on the separation unit 25. By turning the solids, additional fluid may fall through the conveyor and be recovered as effluent. In some embodiments, the deflectors 55 are angled relative to the direction of travel of the material on the top course 53a of the belt to allow material to roll as it passes up the separation unit 25. The deflectors 55 may be arranged in rows with the rows being spaced from the walls of the conveyor to prevent material from being driven into the wall.

[0020] The separation unit 25 includes a tail pulley 51 and head pulley 54 over which the open mesh belt 53 is wrapped. As illustrated in FIGS. 1-5, the head pulley 54 is the drive pulley. The separation unit 25 also includes a tension pulley 56 to maintain tension in the belt 53. The tension pulley 56 is secured within first and second brackets 62, 64 (FIG. 5). The brackets 62, 64 are attached to a support frame 66 that supports the floor 58.

[0021] The floor 58 is attached to two pins 71, 72 (FIGS. 1 and 3) disposed towards the end 76 of the unit 25 at which solids are discharged. The pins 71, 72 define a pivot axis P about which the floor 58 pivots. In this arrangement, the floor 58, support frame 66 and tension pulley 56 may move up and down toward the loading end of the separation unit 25. The weight of the floor 58, support frame 66 and tension pulley 56 maintains tension on the belt 53 by pivoting about pins 71, 72 and pulling down on belt 53 at the tensioning pulley 56.

[0022] The tail pulley 51 extends across the width of the belt 53 and includes teeth 60 (FIG. 6) that protrude through belt mesh openings (preferably through at least 50%, 75%, 90% or through each mesh opening) during rotation to push material bound within the belt through the openings to reduce pluggage of the belt.

[0023] In some embodiments and as shown in FIG. 7, the openings 80 of the belt 53 (FIG. 7) are circumferentially staggered. The belt 53 includes undulating wires or bands 88, with rods 94 which extend through the bands 88. Each band 88 is connected to two rods 94. In such embodiments, in a row 82 of openings 80, the centerline CL.sub.1 (i.e., the centerline being midway between the top and bottom of each opening) of a first set of openings 80A is offset from the centerline CL.sub.2 of adjacent of a second set of openings 80B. The width of the offset is W.sub.1.

[0024] In some embodiments, the teeth 60 of the tail pulley 51 are configured to match the offset of the openings 80. Referring now to FIG. 8, the teeth 60 in each row 75 of the tail pulley 51 are circumferentially staggered. One set of teeth 60A is offset from adjacent teeth 60B. The teeth 60 in each row are offset by a distance W.sub.2. The offset W.sub.2 of the teeth 60 is substantially equal to the offset W.sub.1 between the centerlines CL.sub.1, CL.sub.2 of the belt openings 80 (FIG. 7).

[0025] With reference to FIG. 4, the head pulley 54 includes sprockets 65 that are spaced to rotate the belt 53 around the head pulley 54. Alternatively, the head pulley 51 may extend across the width of the belt 53 and include teeth that protrude through belt mesh openings (preferably through at least 50%, 75%, 90% or through each mesh opening) during rotation. Additionally the tail pulley 51 may extend across the width of the belt 53 and include teeth that protrude through belt mesh openings (preferably through at least 50%, 75%, 90% or through each mesh opening) during rotation.

[0026] The tension pulley 56 includes an auger 68 to convey solids that pass through the top course 53a (FIG. 1) of the belt but do not pass through the lower course 53b. In the illustrated embodiment, the auger 53 has a bi-directional pitch (i.e., one auger flight promotes conveying material from the center of the belt to the left and a second flight conveys material from the center to the right of the belt) to move material off the belt. Such a bi-directional auger may also keep the belt 53 centered.

[0027] The separation unit 25 includes a scraper 74 (FIG. 2), which may be made of a flexible material such as rubber, that contacts the belt 53 while it rotates. The scraper 74 removes material from the belt while the teeth 60 of the tail pulley 51 engage the belt 53. The separation unit 25 includes a plurality of belt supports 70 (FIG. 4) that support the weight of the belt 53 and solids loaded on the belt as the belt 53 moves toward the head pulley 54. The separation unit 25 also includes a series of deflectors 55 that are arranged in rows and are angled relative to the direction of travel of the slurry to turn or otherwise redirect solids that are moving forward on the separation unit 25.

[0028] As slurry contacts the open mesh of the flat-wire belt 53, the slurry falls through both the top and bottom courses 53a, 53b of the belt and slides downward on a floor 58 (FIG. 2) of the separation unit 25 and falls through outlet 61 (FIG. 1). The slurry may be collected and/or further processed. Larger clumps of material are carried by the top course 53a of the belt and may fall within a collection vessel (not shown) or a further processing unit at the solid discharge end 76 (FIG. 1) of the belt.

[0029] Compared to conventional separation units, the separation units described herein have several advantages. Use of deflectors to turn the solids allows the material to be better dewatered. The tension pulley maintains the belt under tension which allows the belt to not need adjustment if stretched. When the loading on the belt changes, the floor and tension pulley may correspondingly pivot up or down which allows the belt tension to be relatively constant which may improve the life of the belt. This arrangement also allows the separation unit to provide a variable amount of belt slack which reduces the frequency at which the belt is manually tensioned. In embodiments in which the tail pulley of the flat-wire belt conveyor includes teeth that protrude through most openings of the mesh belt, better dewatering may be achieved relative to embodiments in which only the head pulley includes such teeth. In embodiments in which the teeth are circumferentially staggered within each row of teeth, the teeth may better match the opening profile of the mesh belt.

[0030] As used herein, the terms about, substantially, essentially and approximately when used in conjunction with ranges of dimensions, concentrations, temperatures or other physical or chemical properties or characteristics is meant to cover variations that may exist in the upper and/or lower limits of the ranges of the properties or characteristics, including, for example, variations resulting from rounding, measurement methodology or other statistical variation.

[0031] When introducing elements of the present disclosure or the embodiment(s) thereof, the articles a, an, the and said are intended to mean that there are one or more of the elements. The terms comprising, including, containing and having are intended to be inclusive and mean that there may be additional elements other than the listed elements. The use of terms indicating a particular orientation (e.g., top, bottom, side, etc.) is for convenience of description and does not require any particular orientation of the item described.

[0032] As various changes could be made in the above constructions and methods without departing from the scope of the disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawing[s] shall be interpreted as illustrative and not in a limiting sense.