FIELD

(0001 J The disclosed embodiments are related to portable filtration devices.

BACKGROUND

[00021 Access to potable water is essential to life. However, potable water is not always available in certain areas. This is particularly true after natural disasters such as fires, flooding, earthquakes, or other possible disasters. In such instances, potable water sources might become contaminated, or the infrastmcture needed to purify a water source might be damaged. As such, individuals might be forced to drink from contaminated water sources. Therefore, disaster relief responses generally include making potable water available as soon as possible to survivors. However, providing potable water supplies and/or large-scale purification systems is slow, costly, and limited in terms of area distribution. Consequently, people located in remote areas, or traveling away from a disaster area, still might not have access to potable water. Therefore, portable filtration systems for use in such situations can also be provided as part of a disaster relief response, or in preparation for a possible disaster.

SUMMARY

1<MI03] A filtration device includes a filtration unit to filter a liquid. The filtration unit includes an inlet and an outlet. An enclosure is associated with the filtration unit. The enclosure includes an interior volume. A container to receive a liquid is in fluid communication with the inlet of the filtration unit. The container is selectively movable between a compact state at least substantially disposed within the interior volume of the enclosure and an expanded state, in the expanded state, the container extends beyond the interior volume of the enclosure.

[01104] A method for filtering a liquid includes: providing a filtration device including a filtration unit, an enclosure associated with the filtration unit, and a container to receive a liquid in. fluid communication with the filtration unit and substantially disposed within, an interior volume of the enclosure in a compact state; expanding the container from the compact state at least substantially disposed within the interior volume of the enclosure to an expanded state extending beyond the interior volume of the enclosure; filling the container with a liquid; and applying pressure to the container to flow the liquid from the container through the enclosure and through the filtration unit..

|0005] It should he appreciated that the foregoing concepts, and additional concepts discussed below, may be arranged in any suitable combination, as the present disclosure is not limited in this respect,

10006] The foregoing and other aspects, embodiments, and features of the present teachings can be more fully understood from the following description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

J0007] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures is represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

[0008] Fig, 1 is a perspective view of a filtration device;

[0009] Fig. 2 is an exploded schematic diagram of the filtration device;

[0010| Fig. 3 is a front view of the filtration device with the flexible bag in the expanded state;

[0011] Fig. 4 is a schematic cross-sectional view of the filtration device of Fig. 3;

[0012] Fig. 5 is a schematic representation of the flexible bag being extracted from the filtration unit:

[0013] Fig. 6 is a schematic representation of the enclosure being removed from, the enclosure;

[0014] Fig. 7 is a schematic representation of the flexible bag. being filled with an untreated liquid;

[0015] Fig. 8 is a schematic representation of the enclosure being coupled to the filtration unit; [0016] . Fig, 9 is a schematic representation of a person drinking from the filtration device;

[0017 J Fig, 10 is a schematic representation of the flexible bag being compressed into the enclosure interior volume;

[0018] Fig. 11 is a perspective view of a filtration device;

(§019] Fig. 12 is a schematic bottom view of a filtration device;

[0020] Fig. 13 is a cross-sectional view of a filtration device including a prefilter;

[0021] Fig. 14 is a perspective view of a prefilter included in a filtration device assembly;

[0022] Fig. 15 is a schematic representation of the filtration unit outlet being opened;

[0023] Fig, 16 is a schematic representation of the filtration unit with a closed outlet;

[0024] Fig. 17 is a schematic representation of the filtration unit with an open outlet;

[0025] Fig. 18 is a schematic perspective view of the flexible bag being extracted from the enclosure:

[00261 Fig. 19 is a schematic bottom view of the flexible bag being extracted from the enclosure;

[0027] Fig. 20 is a schematic representation of the flexible bag in the expanded state;

[0028] Fig. 21 is a schematic representation of the enclosure being selectively decoupled from the filtration unit;

[0029] Fig. 22 is a schematic representation of the flexible bag being filled with an unfiltered liquid;

[0030] Fig. 23 is a schematic representation of the enclosure being selectively recoup! ed to the filtration unit;

[0031] Fig. 24 is a schematic representation of filtration device filled with an unfiltered liquid and ready to filter the liquid; and

[0032] Fig. 25 is a schematic representation of a person drinking from the filtration device.

DETAILED DESCRIPTION

[0033J The inventors have recognized a need for a small portable filtration device that may be used, for example, by individuals in remote areas and/or after disasters. Further, it may be desirable that such a portable filtration device be easily usable by children, adults, elderly individuals, sick, and/or injured individuals. Further, the inventors recognized that due to the portable and temporary nature of such a filtration device, in some instances, it is desirable that the filtration device be manufactured using biodegradable materials to limit the impact on the environment.

(0034] Certain embodiments of the present disclosure relate to a portable filtration device

(also referred to herein as a "filtration device"). The filtration device can be used to filter water and/or other liquids simply and is preferably compact in design. In some embodiments, the filtration device also operates without the use of batteries or other energy storage devices. The filtration device includes an expandable container, such as a flexible bag, that is collapsed and stored inside the filtration device in a compact state when the device is not in use. In use, the expandable container is expanded such that it extends out of the filtration device to hold a liquid for filtration. As described herein, in some embodiments, the liquid contained within the expandable container is filtered by applying hand pressure to the expandable container (e.g., the flexible bag) with sufficient pressure to force the liquid from the expandable container through a filter (e.g., a membrane filter). In such an embodiment, a component such as a pump typically present in portable filtration devices is not needed. After using the filtration device to filter a desired amount of water, the expandable container may be collapsed back into the interior of the filtration device for storage in a compact state. In addition to reducing the size of the filtration device, by storing the expandable container within the interior of the filtration device during transport to an area and during extended usage by an individual, the chance of damage to the expandable container such as tearing or puncturing can be reduced.

[0035] Methods of filtering a liquid using the currently disclosed filtration device are also provided. For example, generally a method for filtering the liquid may include, expanding an expandable container such as a flexible bag by filling it with a liquid to be filtered, applying a pressure to the bag (e.g., by a squeezing motion or other hand motion), thereby forcing water to pass through a filter (e.g.. a membrane filter), filtering the water by isolating unwanted substances (e.g., particles, bacteria, etc.) from the water, and collecting or consuming the filtered water. The expandable container can subsequently be collapsed and stored within the filtration device in a compact state until it is needed again.

{0036] As described in more detail below, the filtration device is capable of being used in a variety of ways. For example, in some cases, the filtration device filters water directly into a user's month or into a secondary container. However, it should be appreciated that in some embodiments the filtration device described herein may have other configurations and/or methods of use (e.g.. adapted to filter water directly into a user's mouth and not a secondary container., or adapted to filter water directly into a secondary container but not into a user's mouth). Other configurations are also possible.

10037] Turning now to the figures, various embodiments of the filtration device, and its methods of use, are described in more detail.

f §038 j Figs. 1 -4 depict one embodiment of a filtration device. In general, the filtration device includes a filtration unit 2 that is selectively and operatively coupled with an enclosure 4. in this embodiment, the expandable container is a flexible bag 6 coupled to the enclosure such that it is in fluid communication with the filtration unit. The flexible bag is movable between a compact state in which it is at least substantially disposed within the interior volume of the enclosure and an expanded state wherein the flexible bag extends beyond the interior volume of the enclosure. The specific interactions of these components as well as additional components are described in more detail below.

[0039} Filtration unit 2 includes an inlet 8 that is in fluid communication with an outlet

10. Outlet 10 may be configured in any appropriate fashion. For example, outlet 10 may be configured to function as a mouthpiece or nozzle that allows a user to filter water directly into his or her mouth upon application of pressure to the flexible bag. Further, in some embodiments outlet 10 may be adapted to be selectively coupled to a secondary container for storing filtered water. The filtration unit may be made of any suitable material. In some cases, the filtration unit is made of an appropriate biodegradable material, such as polylactic acid (PLA). In some embodiments, a cap or other cover, not depicted, may optionally be included to cover outlet 10 of the filtration unit when not in use to prevent contaminants from entering the filtration unit or contaminating the surfaces that contact purified water exiting the filtration unit. 10040] In the depicted embodiment, filtration unit 2 further includes at least one filter 12 disposed in the filtration unit interior between inlet 8 and outlet 10 to filter liquid passing there through. Filter 12 is used to filter unwanted substances such as, but not limited to, particulates and bacteria to purify a liquid. For example, filtration unit 2 may include one or more membrane filters, one or more screen filters, or any other appropriate filter or filter assembly. In some instances, a membrane filter, or other appropriate filter, has an average pore size of, for example, less than or equal to 0.5 microns, less than or equal to 0.4 microns, less than or equal to 0.3 microns, less than or equal to 0.2 microns, less than or equal to 0.15 microns, or less than or equal to 0.1 microns. The size of the pores of the filter can be chosen depending on the level of purification needed. Therefore, other sizes are also possible depending upon the size of the contaminant or organism to be filtered. For example, many parasites and organisms have a size of greater than 0.2 microns so a 0.2 micron pore size may be sufficient to isolate the substances from water during purification. While a specific filter type and various average pore sizes have been described above, it should be understood that any other appropriate filters could be used as the current disclosure is not limited in this fashion. ^' While a sized based filter has been described above, it may be desirable to include other types of filters within the filtration device including, but not limited to, activated carbon filters and other appropriate filters.

[0041] As noted above, the enclosure 4 is selectively coupled with the filtration unit 2.

The selective coupling between the enclosure and filtration unit may be obtained in any appropriate fashion. For example, in one embodiment, the enclosure includes a threaded connection, not depicted, or any other suitable structure that may selectively engage a complementary structure on the filtration unit. Therefore, the enclosure can be attached to the filtration unit when not in use, and separated from the filtration unit when filling the flexible bag with a liquid. As depicted in Figs. 2 and 4, in one embodiment, the enclosure includes an outer element 18 that engages with filtration unit 2 using the coupling noted above. An inner element is disposed, or formed, within the outer element to form an interior volume 28 of the enclosure that houses the flexible bag in its collapsed state. The inner element may be joined to the outer element using any appropriate method including, but not limited to, welding, adhestves, brazing, sonic welding, solder, being integrally formed there with, or any other appropriate method. Enclosure 4 also includes an opening 1 that is fluidly coupled with the flexible bag 6, Further, opening 19 is also in fluid communication with the inlet 8 of the filtration unit 2 when the enclosure is coupled thereto. Thus, opening 1 permits unfiltered liquid to be poured into the flexible bag when the enclosure is detached from filtration unit 2. Further, liquid flows from the flexible bag through opening 19 and into the inlet 8 of filtration unit 2 during filtration of a liquid.

[0042] In one embodiment, the overall dimensions of the enclosure as well as the specific interior volume of the enclosure are shaped and configured to adequately contain the flexible bag in its compact state when the filtration device is not in use. In some embodiments, the enclosure may have dimensions such as a diameter of less than or equal to 10 cm, less than or equal to 7 cm, less than or equal to 5 cm, less than or equal to 4 em, or less than or equal to 3 cm. In some cases, the length of the enclosure may be less than or equal to 10 cm, less than or equal to 7 cm, less than or equal to 5 cm, less than or equal to 4 cm, or less than, or equal to 3 cm.

Combinations of the above-mentioned values are also possible. In addition to the above, depending upon the particular embodiment, the interior volume, contained within the above noted enclosure, may be less than or equal to 100 ml, less than or equal to 80 ml, less than or equal to 60 ml, less than or equal to 40 ml, less than or equal to 20 ml, less than or equal to 15 ml, less than or equal to 10 ml, less than or equal to 5 mi, less than or equal to 2 ml, or any other appropriate volume. For flexible bags having larger volumes, the enclosure may be modified accordingly to house such flexible bags as the current disclosure is not limited to any particular size.

[0043] In certain embodiments, the filtration device may optionally include a prefilter 22 to filter out relatively large particles from, the unfiltered liquid prior to introduction to the flexible bag and/or to prevent clogging of the membrane filter during liquid filtration. In the depicted embodiment, the prefilter is located prior to opening 19 such that large particulates would be prevented from, entering the flexible bag. Depending upon the desired amount of filtration to be provided by the prefilter, the prefilter may have various average pore sizes. For example, the prefilter may have an average pore size of, for example, greater than or equal to 0.5 microns, greater than or equal to I micron, greater than or equal to 2 microns, greater than or equal to 5 microns, greater than or equal to 10 microns, greater than or equal to 25 microns, greater than or equal to 50 microns, greater than or equal to 100 microns, greater than or equal to 200 microns, greater than or equal to 500 microns, greater than, or equal to 1 mm, greater than or equal to 2 mm, or greater than or equal to 5 mm. Other sizes are also possible. As shown illustratively in Fig. 2, prefilter 22 may be a part of the enclosure in some embodiments. However, in other embodiments, the prefilter may be a part of the filtration unit (e.g., adjacent to the membrane filter described above, or separated from the membrane filter), or it may be part of any other appropriate portion of the filter device as the current disclosure is not limited in this fashion. Further, prefilter 22 may be assembled with, or integrally formed with, any of the above noted components using any appropriate manufacturing method.

{00441 In the embodiment depicted in Fig. 4, flexible bag 6 is coupled to enclosure 4 at an attachment portion. 26. Attachment portion 26 may correspond to any appropriate structure including, but not limited to, a shoulder, a compressive seal, or any other appropriate structure. The flexible bag may be attached to attachment portion 26 using any appropriate method including, but not limited to, sonic welding, adhesives, compression, thermal welding, or any other appropriate attachment method. Flexible bag 6 is in fluid communication with filtration, unit 2 through opening 19 which is in fluid communication with inlet 8 of filtration unit 2.

[00451 As noted above, flexible bag 6 is selectively movable between an expanded and compact state. As such, the corresponding volume of the flexible bag varies between an expanded volume and a compact volume. In some embodiments, the flexible bag expands to a particular volume to accommodate the amount of liquid present in the bag. For example, the flexible bag may expand to one liter to accommodate one liter of liquid, or the flexible bag may expand to 2 L to accommodate 2 L of liquid. In other embodiments, the flexible bag may expand to a predetermined volume regardless of the amount of liquid in the bag. For example, the flexible bag may have a predeteniiined. volume of 2 L in the expanded state regardless of whether 1 L or 2 L of liquid are added t the flexible bag. While two specific embodiments of the flexible bag for containing a liquid have been disclosed above, other embodiments are also possible. [0046] The flexible bag may be made of any suitable material. For example, in some cases, the flexible bag is made of a biodegradable material. Further, the flexible bag may be formed of a fabric (e.g., a non-woven fabric) and/or polymer. In some cases, the fabric is inherently waterproof, in other cases, the flexible bag may include a polymeric sheet to make the material substantially waterproof. In one set of embodiments, the flexible bag is made of a linen-PLA tissue. The flexible bag may optionally have a coating on its inner and/or outer surface(s) to make it waterproof (e.g., to prevent leaking). The coating may be formed of any suitable waterproof material including, but not limited to, latex. Other materials and

combinations of materials are also possible. Further, the flexible bag may have any suitable thickness. For example, the thickness of the flexible bag may be less than 5 mm, less than 4 mm, less than 3 mm, less than 2 mm, less than 1 mm, less than 0.5 mm. or less than 0.3 mm. Other thicknesses are also possible.

[0047] In some embodiments, it is desirable to prevent the enclosure from being completely removed from the filtration unit to reduce the likelihood of losing a component of the filtration device. For example in one embodiment, the filtration device includes an optional tethering element such as ring 14 and associated belt 16. As depicted in the figures, ring 14 is disposed on a bottom portion of filtration unit 2. Belt 16 is then attached to enclosure 4 preventing the complete separation of the two components. While a specific tethering system has been depicted, other configurations are possible. For example, a cord tether, a hinge, or any other appropriate structure could be used to permit the enclosure to be selectively attached to the filtration unit while preventing the complete removal of these components from one another.

[0048} In the embodiment depicted in Figs. 1-4, the filtration device includes a removable retention element 24 that is selectively attachable to the bottom surface of the enclosure 4, though other attachment locations for the retention element 24 and corresponding interior volume are also envisioned. Retention element 24 may be selectively attachable to the the enclosure using any appropriate structure including, but not limited to, one or more detents, a threaded connection, a magnetic coupling, an interference fit, complementary components on the retention element and enclosure, or any other appropriate structure. In use, retention element 24 is selectively removed to deploy the flexible bag and allow it to expand out from the enclosure. Further, in some embodiments, retention, element 24 is coupled to the flexible bag such that upon removal of retention element 24, the flexible bag is moved towards its expanded state extending beyond the interior volume of the enclosure 4. Depending upon the embodiment, retention element 24 may also act as a cover to enclose the flexible bag within the interior volume of the enclosure. Other embodiments are also envisioned in which the flexible bag is retained within the interior volume of the enclosure by the retention element but is not completely covered by ^' the associated retention element,

|0049] Having described one embodiment of the filtration device, a method of use for that filtration device is shown in Figs. 5-10. As depicted in the figures, retention element 24 is removed from enclosure 4 by a user grasping and pulling retention element 24, see Fig, 5, As retention element 24 is pulled outwards the flexible bag 6 coupled thereto is expanded such that it extends out of the interior volume of enclosure 4. After expanding the flexible bag 6, filtration unit 2 and enclosure 4 are decoupled as shown in Fig. 6. In the depicted embodiment, a rotational coupling is used and a user rotates the filtration unit 2 and enclosure 4 relative to one another to decouple them. After decoupling the filtration unit 2 and enclosure 4. an unfiltered liquid, such as unfiltered water 40, is poured into the flexible bag through the opening in enclosure 4, see Fig. 7. Subsequent to filling the flexible bag with the unfiltered liquid, enclosure 4 is re-eoupled to filtration unit 2 by screwing, or otherwise attaching, the enclosure to the filtration unit, as depicted in Fig. 8. Pressure may then be applied to flexible bag 6 by a user gripping and pressing the bag using their hands, see Fig. 9. As a user empties flexible bag 6, flexible bag 6 may be repositioned within the interior volume of enclosure 4, see Fig. 10. After filtering the water in the flexible bag 6, retention element 24 may be returned to the closed position to retain the flexible bag 6 within, enclosure 4 until the filtration device is used again. |0050] Another embodiment of the filtration device and its method of use are depicted in

Figs. 11-25. Similar to the above, the filtration device includes a filtration unit 102, and enclosure 104, and a flexible bag 106 disposed within an interior volume of enclosure 104 when in the compact state. In the depicted embodiment, flexible bag 106 has a substantially predefined volume in the expanded state and does not substantially expand beyond that predefined volume to accommodate different volumes of liquid. In addition to the above, the filtration device includes a rotatable cap 130 that selectively opens and closes outlet 1 10 of the filtration unit 102. Additionally, in the depicted embodiment, the retention element used to selectively retain the flexible bag 106 within the interior volume of enclosure 104 includes a retention ring 124a and a tab 124b coupled to the flexible bag 106 and selectively retained within enclosure 104.

[00511 As depicted in Fig. 12. retention ring 124a selectively engages an inner surface of enclosure 1 4 to selectively retain the retention ring 124a and flexible bag 106 within enclosure 104. In the current embodiment, retention ring 124a does not include a covering portion. This may lead to a reduction in weight and cost of the final filtration device. However, in other embodiments, retention ring 124a may include a surface that substantially covers the flexible bag when located within enclosure 104. In the depicted embodiment, a user might grasp either retention ring 124a directly, or alternatively tab 124b, to remove the retention element and expand flexible bag 106 to the expanded state extending beyond the interior volume of enclosure 104. While a retention element incorporating corresponding engaging features on both the retention element and the enclosure is depicted, other arrangements are also possible as noted above.

[0052] Similar to the prior embodiment, as depicted in. Figs. 11 and 13, the current embodiment includes a tethering element incorporating a ring 114 and hinge 116. As above, ring 1 14 and hinge 116 tether filtration unit 102 and enclosure 104 together to help mitigate the chance of losing one or the other component. Further, while a ring and hinge arrangement is depicted, the current disclosure is not limited in this fashion and encompasses other

embodiments as noted above.

[0053] One specific embodiment of a prefilter 122 is depicted hi Figs. 13-14. Similar to the above embodiment, prefilter 122 is disposed on, or within, opening 1 19 of the enclosure. Prefilter 122 comprises one or more disks containing holes 122a. Holes 122a may be arranged in any appropriate pattern and may be sized to prevent contaminants above a predetermined size from entering flexible bag 106 as noted previously, in addition, in embodiments where multiple disks are used, holes 122a located in adjacent disks may be offset relative to one another. Other constructions and arrangements of the prefilter are also possible. While a specific assembly is depicted, prefilter 122 may be assembled with or integrally formed with either the enclosure, filtration unit, or any other appropriate component.

[0054| As depicted in Figs. 15-17, rotatable cap 130 may be grasped by a user and rotated relative to filtration unit 102 to open and close outlet 1 10. Rotatable cap 130 is rotated through at least two positions corresponding to a closed position in which outlet 1 10 is blocked, see Fig. 16, and an open position in which outlet 1 10 is open, see Fig. 17. By using a rotatable cap, or other types of captive caps, the chances of losing the cap may be reduced.

[0055] The method of use for the above disclosed embodiment is similar to the prior embodiment. As depicted in Figs. 18-20 flexible bag 106 is expanded from the compact state positioned within the interior volume of enclosure 104 by decoupling retention ring 124a from the enclosure 104 and pulling the flexible bag 106 outwards to the expanded state. Subsequent to opening the flexible bag 106 to the expanded state, a rotational coupling located between filtration unit 102 and enclosure 104 is decoupled by a user rotating the filtration unit and enclosure relative to one another, see Fig. 21. The filtration unit is ^' then rotated about hinge 116 to uncover the opening to the prefilter 122 and flexible bag 106. Unfiltered liquid 140 is then flowed through prefilter 122 into flexible bag 106. This may be accomplished in any number of ways including, but not limited to, submerging the flexible bag and prefilter in a liquid, pouring a liquid into the flexible bag 106, or any other appropriate method. After filling the flexible bag with the unfiltered liquid, the filtration unit 102 and enclosure 104 are re-coupled to one another to ready the filtration device for filtering the liquid, see Figs. 23-24. A user may then open the cap, not depicted, aod apply pressure to the flexible bag using their iiands to force liquid from the flexible bag through the enclosure and through the filter and filtration unit. The filtered liquid exiting the outlet of filtration unit 102 may either be drank directly by an individual, or alternatively dispensed into a separate container. After filtering the liquid, the flexible bag may be repositioned within the interior volume of the enclosure.

[0056] Due to storage of the flexible bag within the interior of the filtration device, it is possible to provide a portable compact filtration device that is easy to transport. In certain embodiments, the filtration device may be, for example, less than or equal to 30 cm long, less than or equal to 25 cm long, less than or equal to 20 cm long, less than or equal to 15 cm long, less than or equal to 12 cm long, less than or equal to 10 cm long, less than or equal to 8 cm. or less ^' than or equal to 5 cm long. In some embodiments, the filtration device may have an average width (e.g., diameter) of, for example, less than or equal to about 10 cm, less than or equal to about 8 cm, less than or equal to about 6 cm, less than or equal to about 5 cm, or less than or equal to about 3 cm. Other values are also possible. For example, the filtration device may be approximately 12 cm long and approximately 5 cm wide. Additional combinations of the above- noted ranges are also possible.

[0057] In addition to size considerations, the currently disclosed embodiments may also enable the production of a filtration device that is both compact and lightweight. In certain embodiments, the filtration device may have a weight of less than or equal to about 100 g, less than or equal to about 80 g, less than or equal to about 60 g, less than or equal to about 50 g, less than or equal to about 40 g, or less than or equal to about 30 g. For example, in some embodiments, the filtration device has a weight of approximately 50 g. Other weights are also possible.

|0058] As described above, the filtration device has a relatively small size, yet advantageously has an expandable, flexible bag contained within the fdtration device that can be filled to a much larger volume than the size of the filtration device in its compact state. Such a configuration permits the filtration of liquid volumes greater than the original volume of the filtration device in the compact state. In some embodiments, the flexible bag, in the compact stated, may take up a volume of, for example, less than or equal to 100 ml, less than or equal to 80 ml, less than or equal to 60 ml, less than or equal to 40 ml, less than or equal to 20 ml, less than or equal to 15 ml, less than or equal to 10 ml, less than or equal to 5 ml, or less than or equal to 2 ml. The flexible bag may be folded, crumpled, scrunched, or positioned in any suitable collapsed state within the interior volume of the filtration device. In addition to the compact volume, in its expanded state, the flexible bag may have an approximate maximum volume of, for example, greater than or equal to 0.5 liters, greater than or equal to 0.75 liters, greater than or equal to 1 liter, greater than or equal to 1.25 liters, greater than or equal to 1.5 liters, greater than or equal to 2 liters, greater than or equal to 5 liters, or greater than or equal to 10 liters. In certain embodiments, the ratio of the volume taken up by the flexible bag in its expanded state compared to the compact state is approximately greater than 01 ^* equal to 2: 1, greater than or equal to 3: 1, greater than or equal to 5 ; 1 , greater than or equal to 10: 1, greater than or equal to 15: 1, greater than or equal to 20: 1 , greater than or equal to 25: 1 , greater than or equal to 50: ί , greater than or equal to 100: 1 , greater than or equal to 200: 1 , greater than or equal to 500: 1, greater than or equal to 750: 1 , or greater than or equal to 1 ,000: 1. Other ranges are also possible.

[0059] As noted above, in some embodiments, the filtration, device is manufactured using components made from biodegradable and/or natural materials. Examples of possible- biodegradable materials include, but are not limited to, polylaetic acid and it's copolymers, polyaikylene esters, polyamide esters, polyvinyl esters, polyanhydrides, and other appropriate materials. By using materials that are biodegradable and/or natural, the quantity of waste left in the environment when the devices are distributed within a particular area can be greatly diminished. It should be understood that some embodiments of the filtration device may be composed of entirely biodegradable and/or natural materials. Alternatively, the filtration device may include one or more components that are not biodegradable and/or natural. While it is desirable to manufacture a biodegradable filtration device, it should be understood that the filtration device could also be manufactured without using biodegradable and/or natural materials as the current disclosure is not limited to any specific material,

[0060] In some embodiments it may be desirable to provide replaceable components for the filtration device. For example, in some instances, the expandable container (e.g. the flexible bag) is replaceable by providing selective attachment with the enclosure. This selective attachment might be made using any appropriate method including, but not limited to, compression fittings, adbesives, mechanical interfaces, and other appropriate methods.

Additionally, a replaceable filter, or filter cartridge, might be used with the filtration unit. Thus, when a filter becomes unusable, a replacement may be inserted to extend the useful life of the filtration device. While specific replaceable components are described, it should he understood that depending on the embodiment, the filtration device might include any number, and/or combination, of replaceable components, Further, in. other embodiments, the filtration device might not include any replaceable components as the current disclosure is not limited in this fashion. [0061 ] As described above, in some embodiments the filtration device uses hand pressure

(e.g., in a squeezing motion, pressing motion, and/or wringing motion) which reduces the volume of the flexible bag. This action forces the liquid (e.g., unfiltered water) in the flexible bag to pass through the filter located in the filtration unit to filter unwanted material from the liquid. Without wishing to be bound by theory, hand pressure may be more efficient than other types of forces/pressures such as suction to make water pass through filter. For example, the pressure one can apply by hand motion may be about 25% more than suction making filtration using hand pressure easier. Further, use of hand pressure is a universal gesture used throughout the inhabited world during daily life. Thus, without wishing to be bound by theory, it is believed that the ease of use and increased pressures available due to the use of hand pressure facilitates use of the currently disclosed filtration device by children, adults, the elderly, and sick or injured individuals.

[0062] In addition to promoting use of the filtration device by various individuals, the use of hand pressure to pressurize the liquid contained within the flexible bag may enable a relatively high flow of liquid through the filtration device resulting in relatively quick filtration of a given volume of liquid. Consequently, in some embodiments, the filtration and/or flow rate in the filtration device (e.g., as a result of using hand pressure) may be greater than or equal to about 300 ml/min, greater than or equal to about 500 nil/min, greater than or equal to about 700 ml/min, greater than or equal to about 800 ml/min, greater tha or equal to about 1 ,000 ml/min, greater than or equal to about 1,200 ml/min, or greater than or equal to about 1 ,500 ml/min. In certain embodiments, the filtration and/or flow rate in the filtration device may be less than about 5,000 ml/min, less than about 4,000 ml/min, less than about 3,000 ml/min, or less than about 2,000 ml/min. Other values and ranges are also possible. For example, the filtration device may filter a liquid at a rate greater than approximately 700 niL per minute and less than

approximately 1,500 m.L per minute. Other combinations of the above-noted ranges are also possible.

[0063 J While the present teachings have been described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments or examples. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art. Accordingly, the foregoing description and drawings are by way of example only. In particular, the features of all dependent and independent claims and of all embodiments and examples can be combined with each other, as long as they do not contradict each other.