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Title:
IMPROVED DEWATERING SYSTEM FOR SEDIMENT-CONTAINING BAGS OR THE LIKE
Document Type and Number:
WIPO Patent Application WO/2015/102926
Kind Code:
A1
Abstract:
A vacuum-assisted dewatering system includes a bag, a perforated pipe, and a vacuum system. The bag is configured to contain a mixture of a solid in a liquid. The bag includes an outer wall defining an internal volume and an internal tube. The outer wall is formed of a material that is permeable by the liquid. The inner tube is formed of a material that is permeable by the liquid and defines a passage extending through the internal volume. The perforated pipe is received in the passage. The pipe includes an open end. The vacuum system includes a pump that is configured to draw a vacuum on the open end of the perforated pipe.

Inventors:
ANSON RICH (US)
Application Number:
PCT/US2014/071137
Publication Date:
July 09, 2015
Filing Date:
December 18, 2014
Export Citation:
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Assignee:
TERRA CONTRACTING SERVICES LLC (US)
International Classes:
A47L9/14; B01D3/10; B01D46/02; F26B5/14
Foreign References:
US4718925A1988-01-12
US1989409A1935-01-29
US7454847B12008-11-25
US20060102565A12006-05-18
US5810509A1998-09-22
US4952339A1990-08-28
US4121968A1978-10-24
Attorney, Agent or Firm:
BROWN, Marshall J. et al. (3000 K Street NWSuite 60, Washington District of Columbia, US)
Download PDF:
Claims:
WHAT IS CLAIMED IS:

1. A vacuum-assisted dewatering system, comprising:

a bag configured to contain a mixture of a solid in a liquid, including:

an outer wall defining an internal volume, the outer wall comprising a material that is permeable by the liquid, and

an internal tube, the internal tube comprising a material that is permeable by the liquid and defining a passage extending through the internal volume;

a perforated pipe received in the passage, the pipe including an open end; and a vacuum pump configured to draw a vacuum on the open end of the perforated pipe;

wherein the vacuum drawn on the open end draws the liquid from the mixture through the internal tube and into the perforated pipe, while the solid is substantially retained within the bag.

2. The dewatering system of claim 1, further comprising a vibration device configured to vibrate the internal tube.

3. The dewatering system of claim 1, wherein the vibration device is disposed within the passage.

4. The dewatering system of claim 1, wherein the bag comprises a woven filter fabric.

5. The dewatering system of claim 4, wherein the bag comprises a woven polymer fabric.

6. The dewatering system of claim 1, further comprising:

a second internal tube defining a second passage extending through the internal volume; a second perforated pipe received in the second passage, the second perforated pipe comprising an open end; and

a header pipe coupled to the open end of the first perforated pipe and the open and of the second perforated pipe, the header pipe comprising a vacuum opening,

wherein the vacuum pump is in fluid communication with the vacuum opening.

7. The dewatering system of claim 1, wherein the perforated pipe comprises a second end opposite the open end, the second end being closed.

8. The dewatering system of claim 7, wherein the second end extends beyond the bag.

9. The dewatering system of claim 7, wherein the second internal tube is parallel to the first internal tube.

10. The dewatering system of claim 7, wherein the second internal tube is at a different elevation than the first internal tube.

11. A vacuum-assisted dewatering system, comprising:

a bag configured to contain a mixture of a solid in a liquid, including:

an outer wall defining an internal volume, the outer wall comprising a material that is permeable by the liquid, and

a first internal tube, the first internal tube comprising a material that is permeable by the liquid and defining a first passage extending through the internal volume;

a second internal tube, the second internal tube comprising a material that is permeable by the liquid and defining a second passage extending through the internal volume;

a first perforated pipe received in the first passage, the pipe including an open end;

a second perforated pipe received in the second passage, the pipe including an open end; and a header pipe coupled to the open end of the first perforated pipe and the open and of the second perforated pipe,

wherein a vacuum drawn on the header pipe drawn draws the liquid through the first internal tube into the first perforated pipe and through the second internal tube into the second perforated pipe, while the solid is substantially retained within the bag.

12. The vacuum-assisted dewatering system of claim 11, further comprising a vibration device configured to vibrate the internal tube so as to dislodge at least a portion of the mixture from the internal tube.

13. The vacuum-assisted dewatering system of claim 12, wherein the vibration device is disposed within the passage.

14. The dewatering system of claim 11, wherein the bag comprises a woven filter fabric.

15. The dewatering system of claim 11, wherein the first internal tube and the second internal tube comprise a woven filter fabric.

16. The dewatering system of claim 11, wherein the ends of the first internal tube and the second internal tube are coupled to the outer wall.

17. The dewatering system of claim 11, wherein the ends of the first internal tube and the second internal tube extend outside the outer wall through openings in the outer wall.

18. A method of removing liquid from a mixture of a solid in a liquid, comprising: providing a bag formed from a permeable, flexible material, the bag defining an interior and comprising an internal tube defining a passage extending through the interior;

at least partially filling the interior of the bag with a mixture of a solid in a liquid; providing a perforated pipe in the internal tube;

drawing a vacuum on the pipe to draw water into the perforated pipe, while the solid is substantially retained within the bag.

19. The method of claim 18, wherein the interior of the bag is at least 80% filled with the mixture.

20. The method of claim 18, further comprising vibrating the internal tube, thereby dislodging at least a portion of the mixture from the internal tube.

Description:
IMPROVED DEWATERING SYSTEM FOR SEDIMENT-CONTAINING

BAGS OR THE LIKE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of priority from U.S. Provisional Patent Application Serial No. 61/921,712, filed on December 30, 2013, the disclosure of which is hereby incorporated by reference in its entirety for all purposes.

BACKGROUND

[0002] In the dredging industry and other industries, slurry and industrial waste can be separated into liquid and solid sediment components with the use of a permeable fabric. The slurry is pumped into a bag or tube formed from the permeable fabric. The liquid bleeds out through the fabric, leaving the solid sediment inside the bag. However, the bags can be relatively large (e.g., over 150,000 cubic feet) and it can take a long time for the liquid to drain from such a large volume, increasing the duration of the dredging or other industrial process.

SUMMARY

[0003] Various embodiments relate to a vacuum-assisted dewatering system. The vacuum- assisted dewatering system includes a bag, a perforated pipe, and a vacuum system. The bag is configured to contain a mixture of a solid in a liquid. The bag includes an outer wall defining an internal volume and an internal tube. The outer wall is formed of a material that is permeable by the liquid. The inner tube is formed of a material that is permeable by the liquid and defines a passage extending through the internal volume. The perforated pipe is received in the passage. The pipe includes an open end. The vacuum system is configured to draw a vacuum on the open end of the perforated pipe.

[0004] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Various features, aspects, and advantages of the various embodiments described herein will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below.

[0006] FIG. 1 is a schematic block diagram of a dewatering system, according to an exemplary embodiment.

[0007] FIG. 2 is a schematic perspective view of a dewatering bag for use with a dewatering system, according to an exemplary embodiment.

[0008] FIG. 3 is a schematic perspective view of the dewatering bag of FIG. 2 with the top portion of the bag removed.

[0009] FIG. 4 is a schematic top plan view of the bag of FIG. 3 with the top portion of the bag removed.

[0010] FIG. 5 is a detailed schematic perspective view of the bag of FIG. 3 showing a first end of an internal tube.

[0011] FIG. 6 is a detailed schematic top view of the bag of FIG. 3 showing a second end of an internal tube.

DETAILED DESCRIPTION

[0012] Referring to FIG. 1, a dewatering system 10 is shown according to an exemplary embodiment. The dewatering system 10 is configured to process a sludge, slurry or other mixture of solids and liquids to separate at least some of the liquid from the solids. The solid/liquid mixture may be any of a wide variety of industrial and municipal sludges including various sediments, such as river and lake sediments, sand, municipal biosolids, fly ash, copper tailings, etc. [0013] The mixture may be collected from a variety of sources 12. By way of example, in some implementations the mixture may be collected from a naturally occurring body of water (e.g., lakes, rivers, harbors, etc.) or a man-made body of water (e.g., marinas, agricultural ponds, aquaculture facilities, etc.). In other implementations, the mixture may comprise an industrial byproduct from a facility such as a waste water treatment facility, a pulp and paper mill, a mining operation, etc. The mixture may be collected in a holding structure, such as a settling bed or surge basin.

[0014] The mixture may be collected with a variety of processes from the source 12 with a collection device 14. The collection device 14 may be a dredging device (e.g., a suction dredging device, a bucket dredging device, a clamshell dredging device, etc.) that is capable of collecting a mixture from the body of water (from the bottom of the body of water in certain implementations). In other embodiments, the collection device 14 may be a device that routes or transports a mixture from an industrial process to the dewatering system 10.

[0015] The mixture is pumped or otherwise moved into the interior of a bag 20, shown according to an exemplary embodiment in FIG. 2. The bag 20 is a generally closed structure formed from a permeable, flexible material. According to an exemplary embodiment, the bag 20 may be formed from a high strength and permeable woven filter fabric or geotextile. The filter fabric may comprise a polymer such as polypropylene or polyester or any other suitable material with the physical properties (e.g., tensile strength, fatigue strength, compatibility with the mixture to be contained, etc.) to withstand the mixture and the outward pressure acting on the bag 20 by the mixture. In other embodiments, the bag 20 may be formed from any material that is able to withstand the mixture and the outward pressure acting on the bag 20 by the mixture while allowing the passage of the liquid portion of the mixture to pass through the bag 20.

[0016] According to an exemplary embodiment, the bag 20 is constructed as a tube-shaped body. The ends 22 of the tube may be closed with one or more sewn, heat sealed, or otherwise formed seals or may be closed with another fabric panel coupled to the tube-shaped body. In one embodiment, the bag may be relatively large and have a length of approximately 150 ft. and a diameter of approximately 30-40 ft. In other embodiments, embodiments, the bag 20 may be otherwise sized and have a larger or smaller diameter and/or length. For example, a relatively large bag 20 may be configured for use in an industrial facility, while a smaller bag may be configured for use by an individual. In other embodiments, the bag 20 may be constructed as any other suitably shaped closed body that is configured to contain the mixture.

[0017] As shown in FIG. 1, the mixture is provided to the interior 24 of the bag 20 in one embodiment through a discharge hose 18. The discharge hose 18 may be received in a hose inlet formed in the bag 20 or may be received in a small incision or other opening in the bag 20. The discharge hose 18 may be coupled to the bag 20 with a sealing device (e.g., wire, tie, clamp, rope, etc.). According to an exemplary embodiment, the bag 20 is filled with mixture to about 80%.

[0018] Referring now to FIG. 3, the interior 24 of the bag 20 is shown. The bag 20 includes one or more internal tubes 26, shown as a series of generally parallel open-ended tubes 26 (e.g., socks, sleeves, etc.) extending laterally from one side of the bag 20 to the other (e.g.,

perpendicular to the length or longitudinal axis of a tube). The internal tubes 26 are sewn or otherwise fastened to the bag 20. The internal tubes 26 may be formed of the same material as the main body of the bag 20 or may be formed of any flexible, permeable material that is able to withstand the forces exerted by the mixture being dewatered. The internal tubes 26 define passages 28 through the interior 24 of the bag 20 that are open on either side of the bag 20. In other embodiments, the internal tubes 26 may be otherwise oriented, such as parallel to the longitudinal axis of the bag 20. In other embodiments, the tubes 26 may be provided in multiple layers. In other embodiments, the tubes 26 may not be parallel to each other.

[0019] The dewatering system 10 further includes conduits or pipes 30 that are received in the passages 28. The pipes 30 include apertures, shown as perforations 31, to allow a liquid to pass through the walls of the pipe 30 (see FIG. 1). The perforations 31 may comprise, for example, holes, slots, or any other shaped opening that allows for the unobstructed flow of liquid from through the wall of the tube 26. The perforations may be concentrated at one or more locations along the length of the pipe 30 or may be evenly distributed along the length of the pipe 30.

[0020] Referring to FIGS. 4-6, the pipe 30 extends beyond either side of the bag 20. A first end 32 of the pipe 30 is open. A second end 34 of the pipe 30 is closed, such as by a cap 36. The open first ends 32 of multiple pipes 30 may be connected to a common manifold such as a header pipe 38 that runs along the side of the bag 20. In other embodiments, the manifold may be a pipe, or any other hollow structure to which the open first end 32 is coupled such that the interior of the pipe 30 is in fluid communication with the interior of the manifold.

[0021] As in a conventional dewatering system, the liquid in the mixture passes through the permeable bag 20, leaving the solid particles inside the bag 20. Additionally, the dewatering system 10 includes a vacuum system configured to draw vacuum on the interior 24 of the bag 20 to facilitate the evacuation of the liquid from the mixture contained within the bag 20.

According to an exemplary embodiment, the vacuum system may be moveable and may be mounted on and/or pulled by vehicles. As shown in FIG. 1, a vacuum pump 40 is connected to the first end of the 32 pipe 30, either directly or via the header pipe 38, as shown in FIG. 2. The vacuum drawn by the vacuum pump 40 greatly accelerates the dewatering process by drawing liquid out of the mixture contained within the bag 20, through the permeable fabric of the internal tube 26, and into the pipe 30 through the perforations 31. The liquid is discharged from an outlet 42 to an appropriate location. For example, the liquid may be discharged back into the body of water from which the mixture was collected, or the liquid may be discharged into another holding pond or other structure. The liquid may be treated or otherwise processed or may be discharged without additional processing.

[0022] According to an exemplary embodiment, the dewatering system 10 further includes a vibration device 44 (e.g., vibrator, agitator, etc.) that is positioned within the internal tube 26. The vibration device 44 is configured to vibrate the internal tube 26 to dislodge the mixture from the surface of the tube 26 and prevent the tube 26 from being clogged by the solid particles and preventing passage of the liquid (e.g., "binding off). Depending on the material being dewatered, multiple vibration devices 44 may be utilized to prevent the tube 26 from becoming clogged. In one exemplary embodiment, the vibration device 44 is a concrete vibrator including a probe that is extended along the length of the internal tube 26, in parallel to the pipe 30.

[0023] After a desired amount of the liquid has been removed from the mixture, both through the passage of liquid through the material of the bag 20 as well as the vacuum-assisted passage of the liquid and through the material of the tubes 26, the remaining material (e.g., the solid and any remaining liquid) may be further processed.

[0024] Various aspects of the dewatering system 10, including the size of pipes 30, the size of the perforations 31, the number of pipes 30 and tubes 26, the surface area of the tubes 26, the number of dewatering points, and quantity of and type of vibration devices 44 may be varied based on the type and amount of mixture being dewatered and the rapidity of liquid removal desired.

[0025] The construction and arrangement of the elements of the dewatering system as shown in the exemplary embodiments are illustrative only. Although only a few embodiments of the present disclosure have been described in detail, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements. Some like components have been described in the present disclosure using the same reference numerals in different figures. This should not be construed as an implication that these components are identical in all embodiments; various modifications may be made in various different embodiments. It should be noted that the elements and/or assemblies of the enclosure may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations.