WO2022013549A1

WO2022013549A1 - Improvements for water filters

Info

Publication number: WO2022013549A1
Application number: PCT/GB2021/051800
Authority: WO
Inventors: Daniel Neumann; Fabio Salvador
Original assignee: Innotrend Limited
Priority date: 2020-07-14
Filing date: 2021-07-13
Publication date: 2022-01-20
Also published as: GB2597606B; GB202010853D0; GB202110121D0; GB2597606A

Abstract

A filter pouch (20) for receipt within a cartridge (12) of a water filtration apparatus, the cartridge comprising a cup (14) for receiving the filter pouch therein and a lid (16) releasably connectable to the cup, the filter pouch being made of a flexible, water-permeable material shaped to form an enclosure housing filtration media, the pouch having a body portion (22), the body portion being a cup-shaped body portion having an open end, the pouch further comprising a cover (24) over the open end of the body portion, the pouch further comprising a lip (26) arranged around its body portion, the lip being configured to engage a lip engaging portion of the cartridge when the pouch is received therein, the lip of the filter having a protruding ridge thereon. Also provided is a cartridge (12) for receiving a filter pouch.

Description

Improvements for water filters

Field of the Invention

The present invention relates to a filter pouch for a water filtration apparatus. The invention also relates to a filter assembly for water filtration apparatus, the assembly comprising a cartridge for receiving such filter pouches.

Background to the Invention

Portable water filtration apparatus, such as those incorporated into water pitchers are well known. Water filtering pitchers are configured to receive a cartridge having an internal cavity which houses filtration media. The cartridges have inlet and outlet apertures formed therein to allow water to enter and exit the filtration media containing cavity. The cartridge is received in a hopper above the main chamber of the pitcher. Unfiltered water is poured into the hopper, it flows through the filtration media in the cartridge and then filtered water exits the cartridge into the main chamber of the pitcher. Similar cartridges may be used in non-portable water filtration apparatus.

Ion exchange media reduces water hardness and active carbon reduces chloride ions in the water. Over time, the filter media in such filter cartridges becomes spent, and the user must dispose of the cartridge and replace it with a new one.

Summary of the Invention

According to a first aspect of the invention there is provided a filter pouch for receipt within a cartridge of a water filtration apparatus, the cartridge comprising a cup for receiving the filter pouch therein and a lid releasably connectable to the cup, the filter pouch being made of a flexible, water-permeable material shaped to form an enclosure housing filtration media, the pouch having a body portion, the body portion being a cup-shaped body portion having an open end, the pouch further comprising a cover over the open end of the body portion, the pouch further comprising a lip arranged around its body portion, the lip being configured to engage a lip engaging portion of the cartridge when the pouch is received therein, the lip of the filter having a protruding ridge thereon. The use of a flexible and porous filter pouch in domestic water filters presents numerous difficulties. The pouch sits inside a removable cup of a cartridge, the cartridge sitting in a water filtration apparatus such as a water jug. The pouch, the cup and the jug must be watertight in relation to each other to prevent leakage. Any leakage causes reduced filtration efficiency, reducing the amount of contaminants that get filtered out of the water. During first use of the filter pouch, the filtration media swells in the water being filtered and places forces on the pouch. This can cause the pouch to move and deform within its cartridge. With each use over time the pouch swells and can detach from its fitting and deform further. Both effects allow water to pass around the edges of the pouch or pass through the side of the pouch and affects efficiency over time. The lip of the filter pouch is configured to be clamped between part of the cup and lid of a cartridge, holding the filter pouch in place within the cartridge. The water will find the path of least resistance and will flow around the pouch filter if the top edge of the pouch filter is not tightly secured in its housing within the cup. The edge of the lip will not always be 100% uniform or flat due to variations in the tolerances of the material used to form the filter pouch.

The use of the filter over time subjects the media and the pouch to forces due to the swelling and drying out of the filter media. A filter jug will typically be emptied and then refilled the next day. This makes the filter media dry out and shrink. During the next use the media will swell to a greater size and volume. Coupled with the fact that the lip of the pouch may not be not uniform, these factors allow for water to potentially bypass the filter pouch without passing through it and being filtered. Therefore a solution would be desirable, which would maintain a tight seal between the pouch and the cartridge and prevent deformation of the pouch with use over time.

The protruding ridge provided in the present invention aids in preventing water leaking and passing between the outer edge of the pouch and the inside of the cup. The ridge prevents any water leaking and passing between the outer edge of the pouch and the inside of the cup of the cartridge. The ridge also, over time, as the filter is used over many days, prevents movement of the pouch, which would cause deformation of the pouch. The ridge aids in keeping the pouch in place with its lip tightly clamped between the cartridge cup and lid, therefore avoiding unfiltered water from bypassing the pouch and entering the filtered water reservoirs without being filtered. Preferably the lip of the filter pouch extends substantially parallel with the cover of the pouch, the lip having an upper face and a lower face, the lip being shaped to form said protruding ridge and a groove opposing the ridge, the ridge protruding from one of its upper and lower faces and the groove being on the other of the upper and lower faces. In other words, the lip of the filter pouch preferably extends substantially in the plane of the cover of the pouch, the lip being shaped to form a protruding ridge protruding from one of its upper and lower faces and a groove opposing the ridge on the other of the upper and lower faces.

The ridge on the lip of the filter pouch is hollow, the groove forming the hollow of the ridge. The ridge and groove are formed by shaping the flexible, water-permeable material of the filter pouch to form a hollow ridge shape. The ridge and groove are integral with the lip. The groove is recessed in the other of the upper and lower face of the lip from that which the ridge protrudes from.

The lip with integral ridge is configured to be clamped between a lip engaging potion of the cup and a lip engaging portion of the lid when the lid is connected to the cup with the pouch received within the cartridge. The ridge is suitably configured to be clamped between planar portions of the lip engaging potion of the cup and the lip engaging portion of the lid, said lip engaging portions being substantially parallel to one another when the lid is connected to the cup.

The ridge suitably has sides and a peak. The sides of the ridge suitably extend away from the plane of the lip. The sides of the ridge suitably extend slopingly away from the plane of the lip. The sides of the ridge may be substantially planar or may be curved.

The lip may comprise a distal portion, distal of the body portion, ridge and groove, the distal portion of the lip extending substantially in the plane of the cover of the pouch. The distal portion of the lip is substantially planar and suitably extends substantially parallel to the cover of the body portion.

The ridge may be positioned intermediately on the lip, the lip having a proximal portion between the ridge and the body portion, the proximal portion being planar. In embodiments wherein the lip has a proximal portion, the proximal portion may extend substantially in the plane of the cover of the pouch. The ridge and opposing groove preferably encircle the body portion of the pouch

The cover of the pouch is substantially planar. The cover of the pouch extends along a common plane with the lip of the pouch.

The cover and body portion of the pouch are preferably made of the same flexible, water permeable material. According to a further aspect of the invention there is provided a filter assembly for a water filtration apparatus, the filter assembly comprising a filter pouch and a cartridge configured to receive the filter pouch, the filter pouch being made of a flexible, water-permeable material shaped to form an enclosure housing filtration media, the pouch having a body portion and a lip arranged around its body portion, the cartridge comprising a cup for receiving the filter pouch therein and a lid releasably connectable to the cup, the cartridge having at least one lip engaging portion which contacts the lip of the filter pouch when received therein, the lip of the filter pouch and/or the lip engaging portion of the cartridge having a protruding ridge thereon. The upper face of the lip of the pouch suitably faces towards the lid of the cartridge when received therein.

The filter pouch is suitably shaped to correspond with the inner cavity of a cup of a cartridge for holder the filter pouch.

Preferably the ridge protrudes from the lower face of the lip. In such embodiments the opposing groove is in the upper face of the lip.

Preferably the cover is sealed onto the cup-shaped body portion of the pouch. In preferred embodiments the cover is thermally bonded onto the cup-shaped body portion of the pouch.

Preferably a top portion of the cup-shaped body’s open end overlaps an edge portion of the cover to form the lip of the pouch. During manufacture of the filter pouch, the top of the pouch and the sides of the pouch are thermally sealed together to provide a closure to the pouch at its upper edges. This creates a lip around the upper edge of the pouch. The lip formed by the overlap of the top portion of the body portion and the edge portion of the cover is shaped to form the ridge and opposing groove.

The lip may have a second ridge thereon. In other embodiments the lip may have a more than one ridge thereon.

Preferably the or each ridge is elongate and encircles the body portion of the pouch. Preferably the ridge fully encircles the body portion of the pouch.

Preferably the pouch is made of non-woven cloth.

Preferably the filtration media comprises activated carbon, ion exchange resin, or both, or any other material which changes the characteristics of the water.

According to a further aspect of the invention there is provided a filter assembly for a water filtration apparatus, the filter assembly comprising a filter pouch and a cartridge configured to receive the filter pouch, the filter pouch being made of a flexible, water-permeable material shaped to form an enclosure housing filtration media, the pouch having a body portion and a lip arranged around its body portion, the cartridge comprising a cup for receiving the filter pouch therein and a lid releasably connectable to the cup, the cartridge having at least one lip engaging portion which contacts the lip of the filter pouch when received therein, the lip of the filter pouch and/or the lip engaging portion of the cartridge having a protruding ridge thereon. Preferably the assembly includes a filter pouch according to any aspect of the first invention described above.

According to a further aspect of the invention there is provided a filter assembly comprising a filter pouch according to any aspect of the invention as described above and a cartridge configured to receive the filter pouch, the cartridge comprising a cup for receiving the filter pouch therein and a lid releasably connectable to the cup, the cartridge having at least one lip engaging portion which contacts the lip of the filter pouch when received therein.

The cup of the filter assembly may have a shoulder configured to receive the lip of the filter pouch thereon. The lower face of the lip suitably engages the shoulder when the pouch is received by the cup.

The term ‘cup' refers to any structure that is sized to fit into a household water treatment apparatus and, accordingly, is typically longitudinally extending and has a base portion and at least one side wall. The term ‘lid' refers to any structure that may either partially or fully fit on the top portion of a cup.

The lip of the filter pouch has an upper face and a lower face, the ridge preferably being formed on the lower face of the lip, the shoulder of the cup including, in some embodiments, a groove to engage the ridge on the lip of the filter pouch. The groove on the shoulder of the cup may receive the ridge of the lip of the pouch therein. The groove on the cup aids in preventing the filter pouch from becoming dislodged from its clamped position between the cup and the lid.

Preferably the lid has a lip engaging portion configured to engage the lip of the filter pouch when the lid is connected to the cup, thereby pressing the lip against the shoulder of the cup. The upper face of the lip engages the lip engaging portion of the lid when the pouch is received by the cup and the lid is connected to the cup.

In some embodiments the lip engaging portion of the lid and/or the shoulder of the cup may have at least one protruding ridge thereon. This may be instead of or as well as the assembly including at least one ridge on the lip of the filter pouch. Said at least one ridge on the cartridge is configured to engage the lip of the filter pouch when received in the cartridge. Said at least one ridge on the cartridge runs around the cartridge such that it is aligned with the lip of the filter pouch when received in the cartridge. In such embodiments, the lip engaging portion of the lid and/or the shoulder of the cup may have a second ridge thereon. The or each ridge suitably encircles the pouch when received in the cartridge.

Preferably the cartridge comprises clip means for releasably clipping the lid to the cup. This assists with maintaining a constant pressure between the lid, lip and shoulder, to form a reliable seal.

Preferably the filter pouch is shaped to fit flush within the cup of the cartridge. The location of the filter pouch should ideally be snug in the cup of the cartridge to prevent water passing out of the pouch prior to complete passage through the filter media, which would make the filtering less efficient.

The terms “mounted”, “attached”, “connected to”, “connected” are to be broadly understood and may relate to elements that may be directly connected or also connected indirectly by an intermediary element.

Spatially relative terms such as “top”, “bottom”, “horizontal”, “vertical”, “upper”, “lower”, “left”, “right” and the like, are used for ease of description to explain the positioning of one element relative to another element. These terms are intended to encompass different orientations of the assembly in addition to different orientations from those depicted in the figures.

As used herein, the term “comprises” refers to a part or parts of a whole, but does not exclude other parts. That is, the term “comprises” is open language that requires the presence of the recited element or structure or its equivalent, but does not exclude the presence of other elements or structures. The term “comprises” has the same meaning and is interchangeable with the terms “includes” and “has”. The term set has the meaning of one or more of said element. Furthermore, any use of the term “or” as used herein is generally intended to mean “and/or” unless otherwise indicated.

Brief Description of the Drawings

Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows an exploded view of a filter assembly according to the present invention, showing the cartridge cup, cartridge lid and filter pouch exploded from one another;

Figure 2 shows a side view of the filter pouch of Figure 1 with an enlarged portion of a corner of the filter pouch also shown;

Figure 3 shows a top perspective view of the cartridge cup of Figure 1 ;

Figure 4 shows a bottom perspective view of the filter pouch of Figure 1 ; Figure 5 shows a bottom perspective view of the cartridge cup and cartridge lid of Figure 1 exploded from one another; Figure 6 shows a top perspective view of the cartridge of Figure 1 with the lid in place on the cup;

Figure 7 shows a sample filter pouch without a ridge on its lip after having undergone testing.

Description of the Preferred Embodiments

The present embodiments represent currently the best ways known to the applicant of putting the invention into practice. But they are not the only ways in which this can be achieved. They are illustrated, and they will now be described, by way of example only. Common features between the assemblies of the different figures are referenced by common reference numerals.

Referring to Figure 1 , an exploded view of a filter assembly 10 is shown. The filter assembly 10 comprises a cartridge 12, comprising a cup 14 and lid 16, the cartridge 12 receiving a filter pouch 20 in use. The filter pouch contains filtration media, which may be any suitable media that changes the characteristics of the water. Typical filter media types that may be contained in the pouch include activated carbon and/or ion exchange resin. The cartridge lid 16 has inlet apertures and the cartridge cup 14 has outlet apertures formed therein to allow water to enter and exit the filtration media containing cavity. The cartridge 12 is configured to be received by a filter assembly holder in a water filtration apparatus, such as a water filter jug, pitcher or carafe. The jug (or other water filtration apparatus) includes a feed water reservoir which the user fills with water. The water then passes, due to gravity, through the filter assembly 10 and filtered water passes out of the cartridge outlet into a filtered water reservoir of the jug below.

Referring to Figures 1 , 2 and 4, the filter pouch 20 will now be further described. The filter pouch comprises a cup-shaped body portion 22 and a cover 24. In preferred embodiments the cover 24 is sealed to the upper edge of the body portion 22, preferably by thermal bonding, so as to cover the open end of the body portion 22. This seals the filtration media within the internal cavity of the pouch 20. The body portion 22 and cover 24 may be bonded together in other ways, such as by suitable adhesives. The body portion 22 and cover 24 are both made of a flexible, porous material. Said material is preferably a non- woven cloth, which may be made from synthetic or natural fibres. In preferred embodiments the filter pouch is made from biodegradeable or compostable fibres, such as poly-lactic acid (PLA) fibres.

The filter pouch 20 has a lip 26 arranged around its body portion 22. In preferred embodiments the lip 26 is formed by the sealing of the cover 24 to the body portion 22. During such sealing, the overlap of a top portion of the body portion with an edge portion of the cover 24 forms the lip 26. The lip 26 is like a flange disposed around the top of the body portion 22. In the embodiment shown in the figures the lip 26 encircles the upper end of the filter pouch. The lip 26 has an upper face 26a facing away from the body portion and an opposing lower face 26b. In the embodiment in Figures 1 to 6, the filter pouch 20 has one or more ridges on its lip. Said one or more ridges may be on the upper face 26a or lower face 26b of the lip, or there may be one or more ridges on each face. In the embodiment shown in Figures 1 to 6, the filter pouch 20 has a single ridge 28 on the lower face 26b of the lip. The ridge 28 is elongate and protrudes from the lower face 26b of the lip, the ridge 28 fully encircling the body portion of the pouch. The ridge 28 runs substantially in alignment with the perimeter of the lip. The ridge 28 is continuous, although it need not be and may, for example, be formed of a plurality of discrete portions which combine to encircle the body portion of the pouch. In this embodiment the top of the pouch is oval shaped and the ridge 28 forms the same oval shape as the shape of the lip 26.

A mould tool is used to form the pouch. The ridge 28 on the pouch is formed by the mould tool used to form the pouch 20. The heat of the mould welds the cover 24 to the body portion 22 of the pouch and also creates the ridge 28. The mould tool used to manufacture the pouch 20 forms a rise on the lip of the pouch, which comprises the ridge 28. Referring to Figure, 5, in forming the ridge 28, a groove 27 is formed on the upper face 26a of the lip. The shaping of the lip forms a raised ridge 28 that is hollow underneath. The ridge 28 is a protrusion formed from the pouch material itself, by deformation. In other embodiments, the pouch 20 may be formed to include at least one ridge on its lip, without any corresponding groove on the other side. In preferred embodiments the ridge 28 on the pouch 20 has a height of around 0.5 mm from the face 26b of the lip 26 from which it projects, although the height may be other dimensions. Apart from the ridge 28 and the groove 27, the upper and lower faces of the lip are substantially flat.

Referring to Figure 1 , the cup 14 of the cartridge 12 has a shoulder 14a configured to receive the lip 26 of the filter pouch thereon when the filter pouch is received in the cartridge. In the present embodiment the shoulder 14a is a recessed lip formed on an inner wall of the cup 14, near the open end of the cup 14. However, in other embodiments, the shoulder may be at the top, open end of the cup. The shoulder 14a forms a ledge on the inner surface of the cup 14. The shoulder 14a is continuous and runs within the full perimeter of the cup 14. In other embodiments the shoulder may not be continuous, and for example could be formed of a plurality of discrete portions. The shoulder 14a is configured to engage the lip of the pouch when received in the cartridge, therefore the shoulder 14a is a lip engaging portion of the cup 14.

Referring to Figure 5, the lid 16 has a lip engaging portion 16a on its underside configured to engage the lip of the filter pouch when the lid is connected to the cup, thereby pressing the lip against the shoulder 14a of the cup. The upper face 26a of the lip 26 of the pouch engages the lip engaging portion 16a of the lid when the pouch is received by the cup 14 and the lid 16 is connected to the cup. When the lid 16 is assembled to the cup 14 with the pouch 20 in the cup, the lip 26 of the pouch will be clamped between the shoulder 14a and the lid 16, which keeps the pouch in place within the cartridge.

The cartridge 12 comprises clip means for releasably clipping the lid 16 to the cup 14 in order to maintain a constant pressure forcing the lip 26 of the filter pouch against the shoulder 14a, thereby to form a reliable seal. In the present embodiment the clip means comprise first and second resilient snap catches 18, one on each side of the lid 16. Each snap catch 18 is receivable in a corresponding opening 18a in the cup 14 to securely hold the lid in place over the opening of the cup 14, and to clamp the pouch lip in place between the lid 16 and the shoulder 14a. In order to release the lid 16 from the cup, the resilient snap catches 18 should be depressed by the user, which releases each snap catch from its corresponding opening.

Referring to Figure 6, the cup 14 and lid 16 are configured so that the lid 16 is receiveable within a neck portion 17 of the cup 14, the lip engaging portion 16a on the underside of the lid engaging the shoulder 14a in the cup. In some embodiments the shoulder 14a of the cup 14 may have a shallow groove running along it, configured to engage the ridge of the filter pouch when the filter pouch is assembled in the cartridge. In other embodiments wherein there is a ridge on the upper face 26a of the lip, the lid 16 of the cartridge may have a shallow groove running along it, configured to engage the ridge of the filter pouch when the filter pouch is assembled in the cartridge.

Once the filter media in the pouch has become spent, in order to replace the filter media, the user simply removes the lid 16 from the cartridge cup 14, removes the used pouch 20 and replaces it with a new one, then replaces the lid 16 on the cup 14.

Referring to Figure 1 , the pouch has a handle 29 at its top to assist with pulling the pouch out of the cartridge 12 when the filter media needs replacing (although it will be understood that a handle is not necessary). The handle 29 is formed from a strip of material which is bonded to the top of the pouch. The handle 29 is preferably made from the same material as the material of the pouch, i.e. the same non-woven flexible material in preferred embodiments. Referring to Figure 4, the pouch 20 has a recess 21 in its base. The recess 21 is configured to be received over a corresponding projection that projects from the base of the inside of the cup 14. The inside of the cup 14 with projection on its base is not visible in the figures, however the underside of the projection is visible in the base of the cup in Figure 5. The receipt of the projection on the cup in the recess 21 in the base of the pouch helps to locate the pouch within the cartridge.

Overall, the present design prevents water leaking and passing between the outer edge of the filter pouch and the inside of the cup. It also, over time, as the filter is used over many days, prevents movement of the pouch, which would cause deformation of the pouch. Such deformation allows water to leak from the side of the pouch before it passes through the total height of the filter, reducing filtering efficiency. Tests have shown that this deformation reduces efficiency by up to 40%. Table 1 below shows the results for chlorine reduction in the water tested. The results progressively show the reducing efficiency as more water passes through the filter as the filter is used. A commercially available cup refill without a pouch is shown in the column A of Table 1 as sample (X). The efficiency is high at first use (91%) and remains above 80% efficiency after 100 litres. To ensure that the filter media used and conditions were identical in the improved version, a laboratory baseline sample was made to replicate the commercially available sample. This is shown in column B. Results are similar to commercially available sample (X).

A pouch without protruding ridge was used in a cup for column C (Sample Y). The results are significantly worse than the commercially purchased refill and the results in the laboratory baseline sample. Efficiency is ~40 % lower (down to 44%) after 100 litres.

The final column, column D, (sample Z) shows the improved version of the pouch with the protruding ridge on the lip of the pouch. Results stay above 80% after 100 litres, proving the improvement for filter media in a pouch.

Table 1

The effect of the missing protruding ridge can be seen in the deformation of Sample Y (column C in Table 1) after testing, as shown in Figure 7.

As mentioned above, the filter assembly 10 may be received in a filter jug configured to receive such an assembly. It may also be received in a kettle or other portable and/or countertop and/or household water container.

Furthermore, it will be understood the cartridge with filter pouch described herein could be incorporated into a water treatment apparatus mounted to a water tap, such as in a kitchen. In such an embodiment, the water filter assembly 10 may be secured to the outlet of a tap, such as by a screw thread and filtered water provided when the valve to the tap is turned on.

The invention has the advantage of reducing the cost of ongoing production because the use of a replaceable pouch substitutes the need for needing a new cartridge each time the filtration media needs to be changed. Moreover, the use of such a pouch reduces the plastic used in the cartridge and lowers the overall impact on the environment.

In other embodiments there may be one or more protruding ridges on the cartridge which engage the lip of the pouch instead of or as well as there being one or more ridges on the lip of the pouch. For example, the shoulder 14a of the cup may have one or more ridges thereon which engage the lower face 26b of the lip of the pouch. Alternatively or in addition, the lip engaging portion 16a of the lid may have one or more ridges formed thereon. The inclusion of at least one ridge on the cartridge will assist in maintaining a tight seal between the pouch and the cartridge and prevent deformation of the pouch with use over time.

The foregoing description of illustrated embodiments of the present invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed herein. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention, as those skilled in the relevant art will recognize and appreciate. As indicated, these modifications may be made to the present invention in light of the foregoing description of illustrated embodiments of the present invention and are to be included within the spirit and scope of the present invention.

Claims

1. A filter pouch for receipt within a cartridge of a water filtration apparatus, the cartridge comprising a cup for receiving the filter pouch therein and a lid releasably connectable to the cup, the filter pouch being made of a flexible, water-permeable material shaped to form an enclosure housing filtration media, the pouch having a body portion, the body portion being a cup-shaped body portion having an open end, the pouch further comprising a cover over the open end of the body portion, the pouch further comprising a lip arranged around its body portion, the lip being configured to engage a lip engaging portion of the cartridge when the pouch is received therein, the lip of the filter having a protruding ridge thereon.

2. A filter pouch according to claim 1 , wherein the lip of the filter pouch extends substantially parallel with the cover of the pouch, the lip having an upper face and a lower face, the lip being shaped to form said protruding ridge and a groove opposing the ridge, the ridge protruding from one of its upper and lower faces and the groove being on the other of the upper and lower faces.

3. A filter pouch according to claim 1 or 2, wherein the ridge protrudes from the lower face of the lip.

4. A filter pouch according to any preceding claim, wherein the ridge protrudes from the upper face of the lip.

5. A filter pouch according to any preceding claim, wherein the cover is sealed onto the cup-shaped body portion of the pouch.

6. A filter pouch according to any preceding claim, wherein the cover is thermally bonded onto the cup-shaped body portion of the pouch.

7. A filter pouch according to any preceding claim, wherein a top portion of the body portion’s open end overlaps an edge portion of the cover to form the lip of the pouch.

8. A filter pouch according to any preceding claim, wherein the lip has a second ridge thereon.

9. A filter pouch according to any preceding claim, wherein the lip has more than one ridge thereon.

10. A filter pouch according to any preceding claim, wherein the or each ridge encircles the body portion of the pouch.

11. A filter pouch according to any preceding claim, wherein the pouch is made of non- woven cloth.

12. A filter pouch according to any preceding claim, wherein the pouch is made of biodegradeable or compostable material.

13. A filter pouch according to any preceding claim, wherein the pouch is made of polylactic acid.

14. A filter pouch according to any preceding claim, wherein the filtration media comprises activated carbon, ion exchange resin, or both.

15. A filter assembly for a water filtration apparatus, the filter assembly comprising a filter pouch and a cartridge configured to receive the filter pouch, the filter pouch being made of a flexible, water-permeable material shaped to form an enclosure housing filtration media, the pouch having a body portion and a lip arranged around its body portion, the cartridge comprising a cup for receiving the filter pouch therein and a lid releasably connectable to the cup, the cartridge having at least one lip engaging portion which contacts the lip of the filter pouch when received therein, the lip of the filter pouch and/or the lip engaging portion of the cartridge having a protruding ridge thereon.

16. A filter assembly according to claim 15, including a filter pouch according to any of claims 1 to 14.

17. A filter assembly comprising a filter pouch according to any of claims 1 to 14 and a cartridge configured to receive the filter pouch, the cartridge comprising a cup for receiving the filter pouch therein and a lid releasably connectable to the cup, the cartridge having at least one lip engaging portion which contacts the lip of the filter pouch when received therein.

18. A filter assembly according to any of claims 15 to 17, wherein the cup has a shoulder configured to receive the lip of the filter pouch thereon.

19. A filter assembly according to claim 18, wherein the ridge protrudes from the lower face of the lip of the filter pouch, the shoulder of the cup including a groove to engage the ridge on the lip of the filter pouch.

20. A filter assembly according to any of claims 15 to 19, wherein the lid has a lip engaging portion configured to engage the lip of the filter pouch when the lid is connected to the cup, thereby pressing the lip against the shoulder of the cup.

21 . A filter assembly according to claim 20, wherein the lip engaging portion of the lid and/or the shoulder of the cup has a protruding ridge thereon.

22. A filter assembly according to any of claims 15 to 21 , wherein the cartridge comprises clip means for releasably clipping the lid to the cup.

23. A filter assembly according to any of claims 15 to 22, wherein the filter pouch is shaped to fit flush within the cup of the cartridge.