WO2014003841A1

WO2014003841A1 - Gravity feed fluid purification system

Info

Publication number: WO2014003841A1
Application number: PCT/US2013/030679
Authority: WO
Inventors: Robert E. Astle
Original assignee: 3M Innovative Properties Company
Priority date: 2012-06-29
Filing date: 2013-03-13
Publication date: 2014-01-03

Abstract

Provided are water purification systems that are suitable for retrofitting clay pot gravity feed systems. In general, the systems comprise a typical clay pot gravity filter with upper (treatment) and lower (filtrate) chambers, a filter block, such as a gravity flow carbon block, and a flow barrier to prevent or allow water in the upper chamber from contacting and flowing through the block. The system could also include an optional membrane filter. Water is added into the top chamber while the flow barrier is closed so that the water cannot contact or flow through the carbon block. A treatment agent such as chlorine is added to the water to disinfect. After an appropriate contact time, the flow barrier is opened to allow water to flow through the carbon block to the lower chamber. The filter block can remove cysts and chlorine, producing microbiologically safe water. An optional membrane can be added downstream of the carbon block for improved reduction of microbes and particles.

Description

GRAVITY FEED FLUID PURIFICATION SYSTEM

TECHNICAL FIELD

[0001] This disclosure relates to fluid and water purification systems used for treating and filtering fluids, and particularly to gravity feed systems suitable for disinfecting water and subsequent filtering of the water through a filter block such as a carbon filter block.

BACKGROUND

[0002] Gravity feed 'clay pot' systems provide filtered water in areas without modern water infrastructure throughout the world. Typically, these systems contain a 'ceramic candle' filter that filters out sediment and microorganisms. These filters have a slow flow rate and can be expensive. Moreover, to remove chemical contaminants and/or disinfect the resulting water, further treatment is needed.

[0003] There is a need for low cost gravity feed systems that can provide both disinfection and filtration of water.

SUMMARY

[0004] Provided are systems and methods for purifying fluids, specifically, water, the systems being suitable for disinfecting water and subsequent filtering of the water through a filter block such as a carbon filter block. In a first aspect, provided are systems for purifying a fluid comprising: an inlet and an outlet; a treatment chamber; a filtrate chamber; a filter block; and a flow barrier that is movable between a first position where the fluid does not contact the filter block and a second position where the fluid contacts the filter block and enters the filtrate chamber as treated and filtered fluid. In one or more embodiments, the system is a gravity feed system.

[0005] In one embodiment, wherein the filter block is located in the treatment chamber.

Another embodiment provides that the filter block is located in the filtrate chamber. The filter block can be, for example, a composite block comprising activated carbon and an ultrahigh molecular weight polyethylene binder. In a detailed embodiment, the filter block is plasma-treated for hydrophilicity.

[0006] In one embodiment, the flow barrier comprises a sleeve that encircles the filter block.

In another embodiment, the flow barrier comprises a plug that separates the treatment chamber from the filter block. Other embodiments provide the flow barrier as a flap valve.

[0007] The systems can further comprise a membrane filter.

[0008] In a detailed aspect, provided are systems for purifying a fluid comprising: an inlet and an outlet; a treatment chamber; a filtrate chamber; a filter block that is a composite block comprising activated carbon and an ultrahigh molecular weight polyethylene binder and is located in the filtrate chamber; and a flow barrier that is movable between a first position where the fluid does not contact the filter block and a second position where the fluid contacts the filter block and enters the filtrate chamber as treated and filtered fluid.

[0009] The systems can further comprise a mechanism for moving the flow barrier from the first position to the second position and/or from the second position to the first position. In a detailed embodiment, the mechanism comprises a handle affixed to the flow barrier. In another detailed embodiment, the mechanism comprises a handle that is operable external to the treatment chamber and a connecting linkage between the handle and the flow barrier.

[0010] Other aspects provide methods of purifying a fluid comprising: providing a system disclosed herein; putting the flow barrier in the first position; filling the treatment chamber with the fluid; adding a treatment agent to the treatment chamber to treat the fluid; after treating the fluid, putting the flow barrier in the second position to filter the fluid through a filter block; and receiving the filtered and treated fluid in the filtrate chamber.

[0011] The methods can further comprise passing the filtered and treated water through a membrane filter. The treatment agent can be a disinfectant. One detailed embodiment provides that the filter block is in the treatment chamber and the flow barrier is a sleeve. Another detailed embodiment provides that the filter block is in the filtrate chamber and the flow barrier is a plug or flap valve.

[0012] The methods can further comprise using a mechanism for moving the flow barrier from the first position to the second position and/or from the second position to the first position.

[0013] These and other aspects of the invention are described in the detailed description below. In no event should the above summary be construed as a limitation on the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The disclosure may be more completely understood in consideration of the following detailed description of various embodiments of the disclosure in connection with the accompanying drawings, in which:

[0015] FIG. 1A is a schematic drawing of a system in accordance with an embodiment;

[0016] FIG. IB is a schematic drawing of an expanded view of components located in the treatment chamber;

[0017] FIG. 2 is a schematic drawing of a membrane filter located in a filtrate chamber of an embodiment;

[0018] FIG. 3 is a schematic drawing of another embodiment; and

[0019] FIG. 4 is a schematic drawing of another embodiment. DETAILED DESCRIPTION

[0020] Before describing several exemplary embodiments of the invention, it is to be understood that the invention is not limited to the details of construction or process steps set forth in the following description. The invention is capable of other embodiments and of being practiced or being carried out in various ways.

[0021] Provided are water purification systems that are suitable for retrofitting clay pot gravity feed systems. In general, the systems comprise a typical clay pot gravity filter with upper (treatment) and lower (filtrate) chambers, a filter block, such as a gravity flow carbon block, and a flow barrier to prevent or allow water in the upper chamber from contacting and flowing through the block. The system could also include an optional membrane filter. Water is added into the top chamber while the flow barrier is closed so that the water cannot contact or flow through the carbon block. A treatment agent such as chlorine is added to the water to disinfect. After an appropriate contact time, the flow barrier is opened to allow water to flow through the carbon block to the lower chamber. The filter block can remove cysts and chlorine, producing microbiologically safe water. An optional membrane can be added downstream of the carbon block for improved reduction of microbes and particles. Rapid wetting of media in gravity feed systems is important and the bulk wetting property of the carbon block can be improved by rendering it hydrophilic. The carbon block can be embodied in typical cylindrical form or a flat disk that is better suited to gravity flow applications. The block can be made with ultra high molecular weight polyethylene (UHMWPE) and can be scrubbed clean with a brush.

[0022] The following terms shall have, for the purposes of this application, the respective meanings set forth below.

[0023] A "filter block" refers to composite blocks can be made from combinations of sorptive materials, such as adsorbent activated carbon, and polymeric binders, such as ultra high molecular weight polyethylene (UHMW PE), that have been sintered together under conditions of heat and pressure.

[0024] A "carbon block" is a filter block that uses adsorbent activated carbon as the sorptive material.

[0025] A "flow barrier" is a mechanism that prevents fluid, specifically water, from contacting the carbon block. Suitable flow barriers include, but are not limited to plugs, flaps or flap valves, other valves, sleeves, and removable covers.

[0026] The term "UHMW PE" refers to ultra-high molecular weight polyethylene having molecular weight of, for example, at least 750,000 and is described in commonly-owned U.S. Patent No. 7,1 12,280, to Hughes et al., incorporated herein by reference in its entirety.

[0027] "Bulk wetting property" refers to the propensity of an article to absorb and soak up water. By improving hydrophilicity, wetting time of the article can be reduced. U.S. Patent Appln. Pub. No. 2010/0243572 to Stouffer et ah, incorporated herein by reference, discloses one way to render binder particles hydrophilic and more adhesive to carbon particles for use in forming block or other filter elements.

[0028] Turning to the figures, FIGS. 1A and IB are schematic drawings of a system in accordance with an embodiment where purification system 100 has an inlet 102 for receiving water into the treatment chamber 106. Flow barrier 108, in the form of a sleeve, prevents the water from contacting carbon block 1 10. A chlorine tablet 1 16 is added to the treatment chamber to disinfect the water. After a desired treatment time, the flow barrier 108 is lifted off of the carbon block 1 10 and the water then flows through the carbon block 110, which removes the chlorine and other impurities such as cysts. The filtered and treated water from the carbon block then enters the filtrate chamber 1 12. As shown in FIG. 2, further purification can be provided with a membrane filter 1 14 located in the filtrate chamber which can receive the water from the carbon block before it enters the filtrate chamber 1 12. The finally filtered and treated and optionally further purified water exits the system through an outlet 104.

[0029] FIG. 3 is a schematic drawing of another embodiment where purification system 200 has a treatment chamber 206, a flow barrier 208 in the form of a plug, a handle 218 and a connecting linkage 220 between the handle 218 and the plug 208. In this embodiment, the carbon block 210 is located in the filtrate chamber 212. Upon opening the plug 208 with the handle 218 and connecting linkage 220, treated water enters the carbon block 210 and then exits the carbon block to provide both treated and filtered water.

[0030] FIG. 4 is a schematic drawing of another embodiment where purification system 300 has a treatment chamber 306, a flow barrier 308 in the form of a flap or flapper valve, a handle 318, having a lever on the outside to permit operation of the handle without reaching into the treatment chamber, and a connecting linkage 320, such as a chain or string, between the handle 318 and the flap 308. In this embodiment, the carbon block 310 is located in the filtrate chamber 312. Upon opening the plug 308 with the external lever that moves the handle 318 and connecting linkage 320, treated water enters the carbon block 310 and then exits the carbon block to provide both treated and filtered water.

EXAMPLES EXAMPLE 1

[0031] A disk-shaped filter block made from activated carbon and ultra high molecular weight polyethylene (UHMWPE) is put into the bottom chamber of a clay pot gravity feed system such that an inlet of the filter block can receive (is in fluid communication) with an outlet of the upper chamber of the clay pot gravity feed system. The outlet of the upper chamber is blocked by a flap valve. The flap valve is connected to a handle via a string, and the handle is connected to a lever located outside of the upper chamber. When the flap valve is closed, the upper chamber is filled with water to be treated. Chlorine disinfectant is added to the upper chamber and the water is treated for a desired time, at which point the flap valve is opened by using the external handle and the treated water is then filtered through the filter block. Treated and filtered water from the filter block enters the lower chamber and is then available for drinking.

[0032] Reference throughout this specification to "one embodiment," "certain embodiments,"

"one or more embodiments" or "an embodiment" means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases such as "in one or more embodiments," "in certain embodiments," "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily referring to the same embodiment of the invention. Furthermore, the particular features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments.

[0033] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made to the method and apparatus of the present invention without departing from the spirit and scope of the invention. Thus, it is intended that the present invention include modifications and variations that are within the scope of the appended claims and their equivalents.

Claims

What is claimed is:

1. A system for purifying a fluid comprising:

an inlet and an outlet;

a treatment chamber;

a filtrate chamber;

a filter block; and

a flow barrier that is movable between a first position where the fluid does not contact the filter block and a second position where the fluid contacts the filter block and enters the filtrate chamber as treated and filtered fluid.

2. The system of claim 1, wherein the filter block is located in the treatment chamber.

3. The system of claim 1, wherein the flow barrier comprises a sleeve that encircles the filter block.

4. The system of claim 1, wherein the filter block is located in the filtrate chamber.

5. The system of claim 1, wherein the flow barrier comprises a plug that separates the treatment chamber from the filter block.

6. The system of claim 1 further comprising a membrane filter.

7. The system of claim 1, wherein the filter block is a composite block comprising activated carbon and an ultra high molecular weight polyethylene binder.

8. The system of claim 7, wherein the filter block is plasma-treated for hydrophilicity.

9. A gravity feed system for purifying a fluid comprising:

an inlet and an outlet;

a treatment chamber;

a filtrate chamber;

a filter block that is a composite block comprising activated carbon and an ultrahigh molecular weight polyethylene binder and is located in the filtrate chamber; and

10. The gravity feed system of claim 9, wherein the flow barrier comprises a flap valve.

1 1. The gravity system of claim 9, further comprising a mechanism for moving the flow barrier from the first position to the second position and/or from the second position to the first position.

12. The gravity system of claim 1 1, wherein the mechanism comprises a handle affixed to the flow barrier.

13. The gravity system of claim 1 1, wherein the mechanism comprises a handle that is operable external to the treatment chamber and a connecting linkage between the handle and the flow barrier.

14. A method of purifying a fluid comprising:

providing the system of claim 1 ;

putting the flow barrier in the first position;

filling the treatment chamber with the fluid;

adding a treatment agent to the treatment chamber to treat the fluid;

after treating the fluid, putting the flow barrier in the second position to filter the fluid through a filter block; and

receiving the filtered and treated fluid in the filtrate chamber.

15. The method of claim 14 further comprising passing the filtered and treated water through a membrane filter.

16. The method of claim 14, wherein the treatment agent is a disinfectant.

17. The method of claim 14, wherein the filter block is in the treatment chamber and the flow barrier is a sleeve.

18. The method of claim 14, wherein the filter block is in the filtrate chamber and the flow barrier is a plug or flap valve.

19. A method of purifying a fluid comprising:

providing the gravity feed system of claim 9;

putting the flow barrier in the first position;

filling the treatment chamber with the fluid;

adding a treatment agent to the treatment chamber to treat the fluid;

receiving the filtered and treated fluid in the filtrate chamber.

20. The method of claim 19, wherein the system further comprises a mechanism for moving the flow barrier from the first position to the second position and/or from the second position to the first position and the method further comprises using the mechanism to put the flow barrier in the first position.