WO2018224517A1

WO2018224517A1 - Liquid treatment cartridge and system and method of manufacturing and use of a liquid treatment cartridge

Info

Publication number: WO2018224517A1
Application number: PCT/EP2018/064807
Authority: WO
Inventors: Hilmar Walde
Original assignee: Brita Gmbh
Priority date: 2017-06-09
Filing date: 2018-06-06
Publication date: 2018-12-13

Abstract

A liquid treatment cartridge includes a housing and a quantity of dimensionally unstable matter (19) forming at least one liquid treatment medium, encapsulated in an interior space (20) of the housing. The housing includes a first housing component (21) and a second housing component (22), distinct from the first housing component (21). The first housing component (21) includes a liquid-impervious side wall section (27), closed on itself about an axis (23), and a liquid-impervious base wall section (28) at an axial end of the housing. The base wall section (28) includes an indentation (30) into the interior space (20). The indentation (30) is provided with at least one liquid-pervious window for retaining the encapsulated matter (19). The interior space (20) includes a portion (34) that surrounds the indentation (30) and is accessible to the encapsulated matter (19). The second housing component (22) is joined to the first housing component (21) at an axial position on an opposite side of an interior end of the indentation (30) to the axial end of the housing at which the base wall section (28) is located. The encapsulated matter (19) extends to a level enabling it to contact at least part of the liquid-pervious window in an orientation of the liquid treatment cartridge in which the second housing component (22) is situated at a lower level than the base wall section (28).

Description

Title: Liquid treatment cartridge and system and method of manufacturing and use of a liquid treatment cartridge

Description

The invention relates to a liquid treatment cartridge, including

a housing and

a quantity of dimensionally unstable matter forming at least one liquid treatment medium, encapsulated in an interior space of the housing,

wherein the housing includes a first housing component and a sec- ond housing component, distinct from the first housing component,

wherein the first housing component includes a liquid-impervious side wall section, closed on itself about an axis, and a liquid-impervious base wall section at an axial end of the housing,

wherein the base wall section includes an indentation into the inte- rior space,

wherein the indentation is provided with at least one liquid- pervious window for retaining the encapsulated matter,

wherein the interior space includes a portion that surrounds the indentation and is accessible to the encapsulated matter, and

wherein the second housing component is joined to the first housing component at an axial position on an opposite side of an interior end of the indentation to the axial end of the housing at which the base wall section is located.

The invention also relates to a liquid treatment system and a use of such a liquid treatment cartridge. The invention also relates to a method of manufacturing a liquid treatment cartridge, including :

providing a first housing component, a second housing component and a quantity of dimensionally unstable matter forming at least one liquid treatment medium,

wherein the first housing component includes a liquid-impervious side wall section, closed on itself about an axis, and a liquid-impervious base wall section at an axial end,

wherein the base wall section includes an indentation into an interior space surrounded by the side wall section,

wherein the interior space includes a portion that surrounds the indentation and is accessible to the dimensionally unstable matter, and wherein the indentation is provided with at least one liquid- pervious window for retaining the dimensionally unstable matter;

at least partially filling the interior space with the dimensionally unstable matter; and

joining the second housing component to the first housing component at an axial position on an opposite side of an interior end of the indentation to the axial end at which the base wall section is located to encapsulate the matter. EP 2 615 066 Al discloses a water purification cartridge including a container that contains an adsorbent as a filtering material for converting raw water to purified water. A recessed portion is formed on the top surface of the container, and a raw water inlet for introducing raw water into the inside is formed on a side of the recessed portion. An air outlet for exhausting air such as air bubbles generated inside the container is provided on the top surface of the container. The container includes the air outlet in an upper part of a space formed between a sidewall of the recessed portion and an outer wall that constitutes the side wall of the container. The adsorbent as a filtering material is arranged inside the container and below a recessed portion bottom surface. The raw water inlet is not particular limited, but is preferably formed with a mesh-like member. A mesh-like member having an opening smaller than a mini- mum grain size of the adsorbent is preferably used.

The recessed portion bottom wall of the known cartridge appears to be a solid wall. If the mesh size of the mesh-like members is made very small, such as to retain very fine particles, then air bubbles may still form on the mesh, which will block the inflow of water to be treated. It is an object of the invention to provide a liquid treatment cartridge, liquid treatment system, use of a liquid treatment cartridge and method of manufacturing a liquid treatment cartridge, wherein the liquid treatment cartridge has good manufacturability and the inflow of liquid to be treated through the liquid-pervious window is relatively unhindered even if the liquid-pervious window is capable of retaining relatively fine particles.

This object is achieved according to a first aspect by the liquid treatment cartridge according to the invention, which is characterised in that the encapsulated matter extends to a level enabling it to contact at least part of the liquid-pervious window in an orientation of the liquid treatment cartridge in which the second housing component is situated at a lower level than the base wall section. The liquid-pervious wi ndow can be arranged to form an i nlet of the liquid treatment cartridge in use. At least one further liquid-pervious wi ndow forming an outlet, in use, is incl uded i n at least one of the first and sec^¬ ond housi ng components. Contact between the encapsulated matter and the l iquid-pervious wi ndow with which the indentation is provided allows the encapsulated matter to break the surface tension at the surface of the l iquid-pervious wi ndow. This hel ps counter the blocking of apertures in the l iquid-pervious wi ndow by air bubbles even if the apertures are very small . The encapsulated matter can thus include relatively smal l particles. Because a portion of the interior space that surrounds the in^¬ dentation is accessible to the encapsulated matter and the second hous^¬ ing component is joined to the first housi ng component at an axial posi^¬ tion on an opposite side of an i nterior end of the i ndentation to the axial end of the housing at which the base wall section is located, the first housing component can be fi lled with the enca psulated matter through a mouth at an opposite end of the first housing component to the base wal l section . One might rega rd this as an upside down orientation, in that the base wall section wil l be the upper end of the cartridge in use, but the lower end during fil ling . The fill level wil l be sl ightly below the level at which the first and second housing component a re joi ned to^¬ gether, so that the encapsulated matter cannot be trapped i n the joi nt. When the liquid treatment cartridge is subsequently turned over, the level of the encapsulated matter wi ll reach at least that of the interior end of the i ndentation . Thus, relatively efficient use is made of the avai lable interior space. This is particularly the case in comparison with cartridges in which a mesh is positioned between a beaker and a l id and extends across the enti re mouth of the beaker.

The di mensional ly unstable encapsulated matter has no fixed shape as a collective. It can thus enter the portion of the interior space surround- ing the indentation during fil ling and drop out of it again when the l iquid treatment cartridge is turned over. The dimensionally unstable matter may be loose matter, e.g. granular or fibrous matter or a mixture thereof. It may alternatively be reticulated matter. The encapsulated matter is free to move within the interior space and to contact interior surfaces of the first and second housing component bounding the interior space. A bag for holding the encapsulated matter can be dispensed with, which helps ensure that the encapsulated matter spreads out in the interior space without leaving bypass channels.

The encapsulated matter includes matter forming at least one liquid treatment medium. The liquid treatment medium may be for the treatment of liquid in a diffusive process, e.g. sorption, including ion exchange, or elution.

The first housing component is defined by at least one wall, in which are comprised the base wall section and the side wall section. The at least one wall is impervious to liquid, but for any apertures forming liquid inlet or outlet windows. This ensures full contact between the liquid and the encapsulated matter forming at least one liquid treatment medium. The first and second housing component will generally be self-supporting, at least retaining their shape without external support. The indentation is into the interior space, meaning that the base wall section has a concave section seen from the exterior of the liquid treatment cartridge.

It may be that the encapsulated matter includes matter that swells when in contact with liquid. The encapsulated matter extends to a level enabling it to contact at least part of the liquid-pervious window at least in a swollen state arrived at upon contact with the liquid. It may already extend to that level in an essentially dry state. This means that there is no delay on first use before the liquid-pervious window is contacted. The encapsulated matter may extend to a level below an axial end of the interior space at which the base wall section is provided, even after liquid has passed through the liquid treatment cartridge, in the orientation of the liquid treatment cartridge in which the second housing component is situated at a lower level than the base wall section. It is observed that EP 0 219 004 A2 discloses a cartridge having an almost cylindrical housing with a slightly tapering mantle wall, an upper frusto-conical end wall and a lower frusto-conical end wall, as well as a collar, arranged between the upper end wall and the mantle wall, which is sealingly supported by a shoulder in a central opening of a bottom surface of a funnel. In an embodiment, the end walls are formed as hollow cones, so that the upper housing end wall rises towards the edge and the lower housing end wall drops towards the edge. There is no disclosure of where the various component parts of the housing are joined or of the level to which the cartridge is filled with material for im- proving the quality of drinking water.

It is further observed that WO 2009/115482 Al discloses a container for liquid filtration having a beaker at least partially filled with a filter material and at least one outlet window for the liquid. The container has a lid applied to the beaker, which lid is provided with at least one inlet window for the liquid and at least one outlet window for air, wherein the windows are provided with mesh-like structures with mesh apertures. The air outlet window is provided with at least one indentation extending from the plane of the window, which indentation is at least partly provided with at least one mesh structure. The bottom wall of the indenta- tion lies below the edge of the beaker where the beaker is joined to the lid. Thus, the beaker is joined to the lid on the same side of the interior end of the indentation to the axial end of the cartridge at which the lid is located. As a consequence, the container cannot be filled with filter material upside down. The beaker must be filled to a level appreciably be- low its rim, because filter material might otherwise become trapped between the beaker and the lid when the lid is joined to the beaker.

In an embodiment of the liquid treatment cartridge, the liquid-pervious window is provided at an interior end of the indentation. Compared to liquid-pervious windows extending across side walls of the indentation, liquid will flow into the cartridge in a mainly axial direction. This helps counter the formation of stagnation zones in the encapsulated matter forming at least one liquid treatment medium. Furthermore, by filling the interior space with the appropriate amount of matter forming the at least one liquid treatment medium, it can be ensured that essentially the entire area of the liquid-pervious window is contacted by the encapsulated matter in an orientation of the liquid treatment cartridge in which the second housing component is situated at a lower level than the base wall section. At the same time, at least some of the portion of the interior space that surrounds the indentation can be empty of encapsulated matter, so that space is provided for gas to collect and to accommodate any expansion of the encapsulated matter. A side wall of the indentation extending from a mouth at an axial end of the cartridge housing to the liquid-pervious window at the interior end of the indenta- tion and this side wall may be liquid-impervious. The indentation then functions essentially as a funnel to lead the liquid to be treated towards the liquid-pervious window. The side wall may taper from the mouth to the liquid-pervious window. The interior surface of the liquid-pervious window may face mainly in an axial direction, but need not be flat. It may be convex, seen from the interior space, for example.

However, in a particular embodiment of the liquid treatment cartridge, the liquid-pervious window lies essentially in a plane. This embodiment is relatively easy to manufacture. There is no need to provide a mesh with a complicated shape, for example. The liquid- pervious window may, for example, include a mesh cut from a sheet of flexible material, without there being any need to provide a frame for ensuring that mesh remains in contact with the encapsulated matter. The liquid-pervious window may in particular form an essentially planar interior end of the indentation. The plane may be essentially perpendicular to the axis, resulting in relatively uniform axial inflow, in particular if the side wall of the indentation is liquid-impervious. In an embodiment, the liquid-pervious window includes a network structure forming interstices through which liquid can flow.

An alternative would be to provide relatively narrow slits in a wall section forming the liquid-pervious window. However, slits narrow enough to retain very small particles are relatively difficult to form, in particular in moulded plastic components. The networked structure is formed by crossing strands or strips, which may be intertwined or simply intersect to define an array of channels. Possible embodiments of the networked structure therefore include meshes, lattice-like structures and structures including one or more layers of woven or non-woven fabric. In an embodiment, a section of the base wall section defines the indentation and is provided with an aperture covered by a liquid-pervious component distinct from the base wall section and covering the aperture to form the liquid-pervious window.

This embodiment makes it relatively easy to manufacture the base wall section, which can be moulded. It may be moulded with a relatively large aperture, which does not impose particularly onerous tooling requirements. Alternatively, the aperture can be formed subsequent to the moulding step, which again does not require a particularly complicated tool or particularly accurate positioning of such a tool. The liquid- pervious component is then combined with the remainder of the housing such that it sealingly engages the base wall section, forcing the liquid to flow through the liquid-pervious component and preventing particles of encapsulated matter from escaping through the aperture. The liquid- pervious component is thus a mechanical filtration component. It may be a body provided with through-going channels, e.g. a porous body, a perforated plate-shaped body, a moulded grating or a mesh made of in- terlaced strands, e.g. metal strands, in the manner of a sieve. It may also include one or more layers of fabric, wherein a layer of fabric may be a layer of woven fabric or a layer of non-woven fabric, e.g. a fleece. The liquid-pervious component may be joined to a remainder of the housing mechanically, e.g. using one or more fasteners or by means of a shape-lock between it and one or more parts of the housing.

In a variant of this embodiment, the liquid-pervious component is joined, e.g. bonded, around the aperture to the section of the base wall section defining the indentation.

Bonding includes adhesive bonding and welding, including ultrasonic and thermal welding, for example. Where bonding is used, a positive mate^¬ rial joint is formed, meaning that at least one material of which the base wall section is formed and at least one material of which the liquid- pervious component is formed, and optionally an adhesive or filler, are coalesced to form the joint. Bonding also provides a seal and generally does not require any strengthening of the base wall section where it is joined to the liquid-pervious component. Regardless of whether bonding is used or not, the liquid-pervious component is fixed directly to the base wall section in this embodiment. It therefore does not impede ac^¬ cess to the interior space portion surrounding the indentation. Support frames or the like for holding the liquid-pervious component against the base wall section are also not required. Instead, the base wall section directly supports the liquid-pervious component. The liquid-pervious component may be joined to the base wall section on the inside of the housing, which minimises the risk of its becoming detached. The liquid- pervious component may in particular be joined to a flat interior surface of the base wall section, e.g. a surface defined by a planar section of the base wall section located at an interior end of the indentation, in which section the aperture is defined. This facilitates the joining of the liquid- pervious component to the base wall section.

In an embodiment of the liquid treatment cartridge, at least a remainder of the base wall section surrounding the indentation is closed.

That is to say that this remainder is free of perforations or apertures. There are no venting apertures or the like. Gases are simply collected in some of the portion of the interior space surrounding the indentation, above a level of the liquid-permeable window and the encapsulated matter, in use. Its closed nature makes the base wall section relatively easy to manufacture. The base wall section can have a relatively low wall thickness, yet be relatively strong. In an embodiment, the base wall section and the side wall section are integral parts of a wall defining the first housing component.

In this embodiment, the base wall section and the side wall section are part of a component made in one piece. This component is essentially beaker-shaped, but with an indentation in its base. A step of joining a component including the base wall section to a component including the side wall section can be dispensed with. The risk of leaks is reduced. The first housing component may be formed by thermoforming, injec- tion-moulding or blow moulding, for example. Thermoforming uses relatively little material and is well-suited to forming beaker-shaped components.

In an embodiment, the side wall section has a round, e.g. circular, cross- section.

This embodiment has the effect of reducing the formation of stagnation zones in the bed of encapsulated matter. The flow of liquid is relatively uniformly in axial direction. The cross-section of the interior space, with the cross-sectional plane perpendicular to the axis, has a round or circu- lar outline at at least axial positions between the interior end of the indentation and an opposite axial end of the interior space, due to the shape of the side wall section. The circular variant is relatively easy to manufacture and provides the most uniformly axial flow.

In an embodiment, the axis is a central axis of the housing, and the liq- uid-pervious window is centred on the axis.

The central axis may be a body axis of the first housing component and/or the liquid treatment cartridge. In this embodiment, one liquid- pervious window, extending transversely to the axis, suffices to obtain relatively uniform axially directed inflow into the interior space. In an embodiment of the liquid treatment cartridge, the second housing component is a liquid-pervious housing component.

This embodiment increases the throughflow. The second housing component is joined to the first housing component to close a mouth defined by the side wall section. The second housing component may thus in- elude or form a further liquid-pervious window for forming an outlet of the liquid treatment cartridge. The second housing component may be liquid-pervious across at least the area of the mouth covered by the second housing component. It may in particular be uniformly liquid- pervious in a plane perpendicular to the axis, which axis extends from the liquid-pervious window to the mouth. The result is relatively uniform back pressure, so that preferred flow paths through the encapsulated matter are largely avoided.

In a variant of this embodiment, the second housing component includes a liquid-pervious porous body.

This is a particularly effective implementation for ensuring uniform back pressure. The porous body may have uniform properties in lateral direction, including uniform flow resistance. The liquid-pervious porous body may extend laterally across an area corresponding to at least the area of the mouth covered by the second housing component. It may include or be part of a layered structure of porous bodies. In a variant of this embodiment, the porous body is made of bonded matter, e.g. bonded granular matter.

This is a relatively easy way to provide a porous body. The porous body may be made of thermally bonded matter or the binder may be physically or chemically hardened (e.g. using UV radiation) . Granular matter in- eludes particles and powder and results in point bonds that form relatively large voids. Where the porous body includes other materials than the binder, point bonds leave a relatively large surface area of the particles of those other materials uncovered. This is of particular use where those other materials form liquid treatment media for the treatment of liquid in a diffusive process such as sorption (including ion exchange) or elution. In a variant of the embodiment in which the second housing component includes a liquid-pervious porous body, the second housing component includes at least one sheet of fabric covering a surface of the porous body. Thus, the porous body may be relatively brittle, e.g. made of only loosely bound granular matter. The surface covering will help counter abrasion, as well as trapping any splinters that have become detached from the porous body.

In a variant of the embodiment in which the second housing component is a liquid-pervious housing component, at least a liquid-pervious section of the second housing component extends laterally across an entire area defined by the side wall section and closed by the second housing component.

This further improves the uniformity of flow in the axial direction and helps prevent the establishment of preferred flow paths through the encapsulated matter.

In a variant of the embodiment in which the second housing component is a liquid-pervious housing component, the second housing component is a planar housing component. If the second housing component includes a liquid-pervious porous body, this may also be a planar porous body. The second housing component provides relatively uniform back pressure without complicated further measures. Furthermore, its manufacture is facilitated, because it can be separated from a plate of sheet of material, rather than being individual- ly moulded, for example. Furthermore, a flat major surface of the sec- ond housing component is relatively easy to bond to the first housing component, e.g. to a flange thereof, at an edge of the major surface.

In a variant of the embodiment in which the second housing component is a liquid-pervious housing component, the second housing component includes at least one medium for physicochemical treatment of liquid, e.g. a medium for the treatment of liquid by sorption, e.g. activated carbon.

The second, liquid-pervious, housing component thus increases the treatment capacity of the liquid treatment cartridge, so that a smaller amount of encapsulated matter is required, or the treatment capacity is increased. Also, a separation of liquid treatment media can be achieved, with one type of treatment being carried out by the encapsulated matter and another by the medium or media incorporated in the second housing component. It is therefore not necessary to mix several types of materi- al to provide the encapsulated matter. Recycling is also simplified, since the contents of the interior space can be removed separately and then need undergo fewer or no separation steps. Where the medium incorporated in the second housing component is activated carbon, a relatively compact cartridge can be provided, because a bed of granular or fibrous activated carbon is much more voluminous than bound activated carbon with the same treatment capacity. The space inside the liquid treatment cartridge can thus be used for other liquid treatment media, such as ion exchange materials. Where the second housing component includes a porous body, the liquid treatment medium may be incorporated in that porous body. Such a porous body may be a body formed of bonded matter, e.g. bonded granular matter.

In an embodiment of the liquid treatment cartridge, the second housing component is dimensionally stable. This means that the second housing component has a fixed shape under load, being self-supporting. The second housing component may define the largest lateral dimension of the liquid treatment cartridge. Such a cartridge can be placed in sealed relation in an opening of a container forming a reservoir of liquid to be treated without the need for a support structure extending across that opening to support the cartridge. It suffices to hold the cartridge, in particular the second housing component, at an edge.

In an embodiment of the liquid treatment cartridge, the side wall section has a rim at an opposite axial end to the axial end at which the base wall section is provided, and the second housing component is received with its lateral surface below a level of the rim.

The edge of the lateral surface of the second housing component closest to the rim may be flush with the rim or set back in axial direction with respect to the rim. In this embodiment, the first housing component forms a kind of socket for receiving the second housing component. In this manner, the side wall section of the first housing component shields the second housing component. The second housing component can thus be relatively brittle. It may in particular consist mainly or exclu- sively of a relatively brittle porous body. Furthermore, the lateral surface of the second housing component may be liquid-pervious, with bypasses of liquid through this lateral surface being prevented by the side wall section of the first housing component and optionally by sealant provided between the lateral surface of the second housing component and the first housing component. This embodiment may also provide a cartridge with an aesthetically pleasing appearance, even if the appearance of the lateral surface of the second housing component itself is not particularly attractive. In an embodiment of the liquid treatment cartridge, the side wall section flares outwards to define a circumferential surface section facing away from the base wall section in axial direction, and an edge section of a surface of the second housing component facing in an opposite axial di- rection is placed against the circumferential surface section.

The circumferential surface section facing away from the base wall section may be the surface of a flange defining the axial end of the first housing component opposite the axial end at which the base wall section is provided. Alternatively, the circumferential surface section may be due to a step in the side wall section extending around the circumference of the first housing component and located at an axial position between the mouth and the base wall section. In either case, the second housing component will have a relatively well-defined axial position with respect to the base well section. The height of the encapsulated matter, supported by the second housing component in use, will be relatively well-defined. This also goes for the portion of the interior space surrounding the indentation, which is to be left empty in order to collect gases or to allow the encapsulated matter to expand. As a bonus effect, a circumferentially protruding rim is provided due to the flaring outwards of the side wall section. This provides an exterior surface through which a mainly axially directed clamping force and/or against which a seal can be applied by a part of the cartridge seat. The clamping force will tend to press the edge section of the surface of the second housing component against the circumferential surface section of the first housing component even more tightly, thus also preventing bypasses between the first housing component and the second housing component.

In a variant of this embodiment, a bond is formed between the first housing component and the second housing component at an interface between the circumferential surface section of the side wall section and the edge section of the surface of the second housing component.

Bonding includes adhesive bonding and welding, including ultrasonic and thermal welding, for example. At least one material of which the first housing component is made and at least one material of which the second housing component is made, and optionally an adhesive or filler, are coalesced to form the joint. The materials of the first housing component and the second housing component forming the bond may be the same. In this embodiment, a relatively large contact area is provided for the bond.

In an embodiment of the liquid treatment cartridge, the first housing component and at least an exterior part of the second housing component comprise a common material, e.g. a thermoplastic material .

This embodiment is easier to recycle or at least facilitates the formation of a bond between the first and second housing component. The thermoplastic material allows the first and second housing components to be bonded without the use of adhesives or fillers.

An embodiment of the liquid treatment cartridge is provided with a circumferential rim protruding laterally with respect to a remainder of the side wall section.

The rim may allow for easy stacking of first housing components at an intermediate stage in the manufacturing process of the cartridge, by supporting first housing components higher up in the stack. It may also co-operate with a cartridge seat to hold the liquid treatment cartridge in a sealed relation to a conduit for carrying liquid to be treated, such that the liquid is forced to flow through the liquid treatment cartridge. Fur- thermore, it presents an axially facing surface section, which may be flat, against which the second housing component may be placed to join it to the first housing component in a sealed relation.

In an embodiment of the liquid treatment cartridge, the encapsulated matter has a volume smaller than a volume of the interior space.

The volume of the encapsulated matter may be its volume in dry state or on contact with liquid. In this embodiment, space is provided for gas. This may include gas generated in the liquid treatment process, e.g. CO₂ in the case of decarbonisation. Furthermore, space is provided to ac- commodate swelling of the encapsulated matter on contact with the liquid.

In an embodiment of the liquid treatment cartridge, the encapsulated matter includes at least some ion exchange material, e.g. cation exchange material in the hydrogen form. Ion exchange resins have a tendency to swell on contact with liquid. The portion of the interior space surrounding the indentation, which is located at or above the level of the liquid-pervious window in use, is suitable both for collecting gas and for providing space into which the encapsulated matter can expand. Cation exchange material in the hy- drogen form will cause CO₂ to be generated when used to decarbonise aqueous liquids such as mains drinking water.

In a variant of this embodiment, the encapsulated matter includes at most 20 % by weight of activated carbon, e.g. at most 10 % by weight, e.g. at most trace amounts of activated carbon. A low amount of activated carbon makes more efficient use of the available space inside the liquid treatment cartridge. Granulated activated carbon for use in mixed beds with ion exchange beads tends to be relatively coarse. It is thus relatively ineffective as a liquid treatment medium given its volume. In particular if the activated carbon is incorporated into the second housing component, less of it need be used overall for the liquid treatment cartridge to be effective, e.g. in reducing the concentration of organic substances, chloramines and chlorine in drinking water. Trace amounts of activated carbon are amounts small enough not to require separation when the matter forming at least one liquid treatment medium and including ion exchange material is recycled.

Thus, activated carbon is essentially absent, except for such amounts as might be introduced due to abrasion from components of the liquid treatment cartridge made of bound carbon. This embodiment can be recycled relatively easily and economically, because energy-intensive separation of the activated carbon is not required. Furthermore, fewer or no energy-intensive mixing steps are required to obtain the matter to be encapsulated in the liquid treatment cartridge.

According to another aspect, the liquid treatment system according to the invention includes:

a container for forming a reservoir of liquid to be treated;

a liquid treatment cartridge according to any one of the preceding claims; and

a seat for receiving the liquid treatment cartridge, located at an outlet of the container and arranged to hold the liquid treatment cartridge in a sealed relation to the outlet. The system may be a purely gravity-driven liquid treatment system or it may include a pump, e.g. a suction pump for drawing liquid from the container through the liquid treatment cartridge or a pump for pressurising the contents of the container. The liquid treatment system may be comprised in an appliance for preparing a beverage, e.g. an appliance for preparing a hot beverage, such as a coffee maker or an electrical kettle. The seat is arranged to hold the liquid treatment cartridge in a sealed relation to the outlet, so that liquid can pass through the outlet only by flowing through the liquid treatment cartridge, or optionally also through one of a limited number of defined bypass passages.

In an embodiment, further including a vessel for collecting the treated liquid, the container is arranged to be suspended above a bottom of the vessel.

The vessel may be provided with a pouring spout, thus taking the shape of a carafe or jug. The vessel may alternatively be provided with a spigot. Such a variant may be comprised in a refrigerator. The container may be suspended completely within the vessel or partly or completely on top of it.

In an embodiment of the liquid treatment system, the liquid treatment cartridge, when mounted in the seat, is located with an axial end at which the base wall section is provided at or below a level of an interior surface of a bottom wall of the container.

This allows at least the container to be emptied fully of liquid to be treated without removing the liquid treatment cartridge. The indentation provides that the liquid-pervious window is at an even lower level, and the indentation may thus act as a type of funnel for the liquid to be treated.

In an embodiment of the liquid treatment system, the seat is arranged to hold the liquid treatment cartridge in an orientation in which the liquid- pervious window forms an inlet of the liquid treatment cartridge. Gases thus rise up into the portion of the interior space surrounding the indentation. The encapsulated matter still contacts the liquid-pervious window, so that the inflow of liquid is facilitated even if the liquid- pervious window is configured to retain relatively small particles. In an embodiment of the liquid treatment system, the housing of the liquid treatment cartridge includes at least one lateral part and the seat is arranged to engage the at least one lateral part to hold the liquid treatment cartridge.

The seat need not obstruct the flow of liquid, because engagement be- tween the seat and the liquid treatment cartridge is laterally with respect to the axial direction of flow. The second housing component may include a liquid-pervious section extending laterally across the whole area covered by it of a mouth defined by the side wall section. This section is not obstructed by any part of the seat. This provides for relatively uni- form flow and relatively high rates of flow, even in a purely gravity- driven system.

In a variant of this embodiment, the lateral part protrudes laterally with respect to a remainder of the side wall section along a circumference of the housing of the liquid treatment cartridge, and the seat includes a clamping mechanism for sealingly engaging the protruding part, e.g. on opposite sides of the protruding part in axial direction.

This embodiment is relatively versatile, because the same cartridge seat can alternatively hold a planar, e.g. disc-shaped, filtration element.

Such filtration elements are generally sold in the form of discs of bonded activated carbon for removing mainly chlorine and chloramine from mains drinking water. That kind of treatment suffices to obtain palatable mains drinking water in certain areas. In other areas, the liquid treatment cartridge presented herein may be used instead and include in its interior encapsulated matter including ion exchange material for softening, decarbonising or demineralising the mains drinking water. The container and cartridge seat would be the same for each application and can be manufactured in large production runs for sale in all of the areas.

According to another aspect of the invention, there is provided a use of a liquid treatment cartridge according to the invention in a throughflow mode, such that the liquid-pervious window forms an inlet.

According to another aspect of the invention, the method of manufactur- ing a liquid treatment cartridge is characterised in that the interior space is filled with an amount of matter such that, in an orientation of the liquid treatment cartridge in which the second housing component is situated at a lower level than the base wall section, the encapsulated matter extends to a level enabling it to contact at least part of the liquid- pervious window.

The dimensionally unstable matter has no fixed shape as a collective. In the filling step, it is able to enter the portion of the interior space surrounding the indentation, so that the fill level can be well below the location at which the first housing component is joined to the second housing component. This helps prevent the matter from becoming trapped in the joint and thereby weakening it or even preventing a sealed connection. However, it is still possible to fill the interior space with a sufficient amount of encapsulated matter that it contacts the liquid-pervious window when the liquid treatment cartridge is turned over into its operational orientation. Then, the interior space portion is available for collecting gases and accommodating any expansion of the encapsulated matter. The encapsulated matter extends to a level below an axial end of the interior space at which the base wall section is provided, even after liquid has passed through the liquid treatment cartridge and thus contacted the encapsulated matter. The encapsulated matter may, however, float up during the passing of liquid through the liquid treatment cartridge and then contact the base wall section. In an embodiment of the method, wherein a section of the base wall section defines the indentation and is provided with an aperture, the method includes covering the aperture by a liquid-pervious component to form the liquid-pervious window.

This is easier than forming a pervious window capable of retaining small particles directly in a wall of the first housing component.

In a variant, the liquid-pervious component is joined, e.g. bonded, around the aperture to the section of the base wall section defining the indentation.

In a variant of the embodiment in which a section of the base wall sec- tion defines the indentation and is provided with an aperture, the aperture is provided at a bottom of the indentation.

An embodiment of the method includes forming at least the base wall section and the side wall section of the first housing component in one piece. In an embodiment of the method, wherein the side wall section flares outwards to define a circumferential surface section facing in axial direction away from the base wall section, joining the second housing component to the first housing component includes placing an edge section of a surface of the second housing component against the circumferential surface section. In a variant of this embodiment, filling the interior space with the matter includes filling the interior space to a level below the circumferential surface section.

This helps avoid that the matter becomes trapped between the first and second housing component. Furthermore, when the cartridge is turned over, a portion of the interior space surrounding the indentation is left empty.

An embodiment of the method includes manufacturing the second housing component, wherein manufacturing the second housing component includes manufacturing a liquid-pervious porous body.

In a variant of this embodiment, the liquid-pervious porous body is manufactured by bonding, e.g. thermally bonding, particulate matter, e.g. particulate matter forming at least one liquid treatment medium for physicochemical treatment of liquid. In a particular variant, the liquid-pervious porous body is separated from a remainder of a sheet of bonded particulate matter.

In an embodiment of the method, a liquid treatment cartridge according to the invention is manufactured.

The invention will be explained in further detail with reference to the accompanying drawings, in which :

Fig. 1 is a schematic side view of a liquid treatment system including a seat for receiving a replaceable liquid treatment cartridge;

Fig. 2 is a cross-sectional view of part of the seat;

Fig. 3 is a perspective view of a holding ring for clamping the replacea- ble liquid treatment cartridge in the seat; Fig. 4 is a cross-sectional view of the assembled seat without the replaceable liquid treatment cartridge;

Fig. 5 is a perspective view of a first housing component of the replaceable liquid treatment cartridge;

Fig. 6 is a cross-sectional view of the first housing component;

Fig. 7 is a cross-sectional view of a detail of the first housing component;

Fig. 8 is a cross-sectional view of the first housing component stacked on top of another first housing component;

Fig. 9 is a cross-sectional view of the replaceable liquid treatment cartridge in an upside-down orientation;

Fig. 10 is a cross-sectional view of the replaceable liquid treatment cartridge in its operative orientation;

Fig. H is a schematic cross-sectional view (not to scale) of a second, liq- uid-pervious cartridge housing component;

Fig. 12 is a simplified diagram of a production line for manufacturing the replaceable liquid treatment cartridge; and

Fig. 13 is a schematic view of an apparatus for manufacturing the liquid-pervious cartridge housing component of Fig. 11. A gravity-driven liquid treatment system 1 (Fig. 1) for the treatment of aqueous liquids such as drinking water (e.g. mains drinking water) will be used as an example to describe a liquid treatment system comprising a container for forming a reservoir of liquid to be treated, a replaceable liquid treatment cartridge 2 (Figs. 9, 10) and a seat for receiving the car- tridge 2, wherein the seat is located at an outlet of the container and arranged to hold the cartridge 2 in a sealed relation to the outlet. The liquid to be treated is thus forced to flow through the cartridge 2 on its way out of the container under operation of gravity. In the example, the container is provided in the form of a funnel 3 (Fig. 1), arranged to be suspended in a vessel for collecting the treated liquid. In the example, the vessel is provided in the form of a jug 4. In other embodiments, it may be a carafe or a keg or tank provided with a spigot for dispensing treated liquid, e.g. a tank for placement in a refrigerator.

The jug 4 is provided with a lid 5 with a fill opening closed by a closure part 6. Liquid to be treated can be poured into the funnel 3 without removing the lid 5. A pivotable cover part 7 closes the mouth of a spout 8 from which treated liquid can be poured. The funnel 3 may be suspended in the jug 4 by means of a rim of the funnel 3 supported by a ledge 9 formed at a mouth of the jug 4. Alternative structures for supporting the funnel 3 in a suspended position in the jug 4 are possible.

The funnel 3 is provided with a sleeve 10 extending from a bottom wall of the funnel 3. The sleeve 10 has a mouth at a level of the bottom wall of the funnel 3. In effect, the sleeve 10 terminates at an aperture in the bottom wall of the funnel 3. The sleeve 10 may be an integral part of the funnel 3 or a distinct component sealingly joined to it. The walls of the funnel 3 and the sleeve 10 are essentially impervious to the liquid to be treated.

It is convenient to define a system reference axis 11 (Fig. 2) having an essentially upright orientation in use. The overall direction of flow of the liquid is in the axial direction. The sleeve 10 may be cylindrical or have a varying cross-section in axial direction. It need not be circular in cross-section, but may be polygonal or oval in other embodiments.

However, the cross-section corresponds generally to that of the cartridge 2, and its circular cross-section is one of several features contributing to uniformity of flow through the cartridge 2 in axial direction. The sleeve 10 is provided with a cartridge seat for holding the

cartridge 2 in sealed relation to the sleeve 10, so that liquid can only exit the funnel 3 by flowing through the cartridge 2. A well-defined bypass may be provided in an alternative embodiment, if a defined degree of treatment is desired.

In the illustrated example, the cartridge seat is provided at an opposite end of the sleeve 10 to the bottom wall of the funnel 3. The seat is compatible with planar, e.g. disc-shaped, filter elements of the type described more fully in WO 2012/175656 Al and WO 2015/004085 Al, for example. The seat includes a receiving part 12, a mounting ring 13, a sealing element 14 and a threaded section 15 of the sleeve 10. The threaded section 15 co-operates with a screw thread 16 with which the mounting ring 13 is provided. The sealing element 14 prevents bypasses of liquid between the receiving part 12 and the sleeve 10. The receiving part 12 defines a socket for receiving a planar, in this example disc-shaped, filter element. The receiving part 12 may include one or more resilient parts. It may in particular be manufactured using multi-material injection-moulding or overmoulding.

The seat is arranged to clamp the planar filter element between parts contacting its opposing major faces at their edges. The clamping forces are thus exerted in axial direction. In the illustrated embodiment, the mounting ring 13 is provided with protrusions 17. The receiving part 12 is provided with a resilient lip 18, closed on itself around the system reference axis 11 and protruding in axial direction. In other embodiments, there may be several such lips, arranged concentrically for example. In yet another alternative embodiment, the cartridge seat may provide a lateral seal that engages a lateral surface of the filter disc along its cir- cumference. An example of such an arrangement is disclosed in EP 3 015 431 Al .

Although not itself disc-shaped or even planar, the cartridge 2 is shaped to fit the cartridge seat of the example, wherein a section of the car- tridge extends through an aperture in the receiving part 12 into the sleeve 10. In this position, an axial end of the cartridge 2 proximal to the mouth of the sleeve 10 where the latter joins the funnel 3 or other container for forming the reservoir of liquid to be treated is at or below a level of an interior surface of the bottom wall of the funnel 3 or other container. Thus, the funnel 3 or container can empty completely. There will at most be a small amount of liquid between the cartridge 2 and the sleeve 10.

The cartridge 2 of the example is relatively simple. It has a housing encapsulating matter 19 forming at least one liquid treatment medium, which is encapsulated in an interior space 20. The housing includes a first housing component 21 and a second, liquid-pervious, housing component 22. It is convenient to define a cartridge reference axis 23, substantially aligned with the system reference axis 11 when the cartridge 2 is correctly positioned in the cartridge seat. The second housing component 22 of the example may be of the type described more fully in WO 2012/175656 Al and WO 2015/004085 Al, for example. Thus, the second housing component 22 is of the type and configuration for which the cartridge seat is designed. The second housing component 22 is disc-shaped in the illustrated embodiment, because the first housing component has a circular cross-section. The second housing component 22 includes a porous body 24 (Fig. 11). The porous body 24 is made of bonded matter, which includes a binder and at least one active material for physicochemical treatment of liquid. In particu- lar, the matter includes at least one sorbent, including specifically activated carbon. The bonded matter may be particulate matter, forming point-bonds that keep the porous body 24 together and define interstices forming the pores of the porous body. The binder particles may have a mean diameter larger than that of the particles of the active liquid treatment material, so that the pore size is relatively large but the active material presents a relatively large surface area. The binder may be a thermoplastic binder. The melting point of the binder (determined using differential scanning calorimetry) is at least 120° C, e.g. in the range of 120-150° C. The binder is thermally stable to at least 300° C. Suitable binders include ultra-high density polyethylene. Further details of manufacturing methods are provided in StrauB, S., "Gesinterte Kunststoff- Formteile fur die Fest-/Flussig-Filtration, Technische Mitteilungen, £5 (2), July 1992, pp. 100-104. Typically, the mean pore size (measured by determining the Mean Flow Path) in the majority of the porous body 24 will be larger than 2 μΐτι, in particular larger than 5 μΐ . The mean pore size will generally be smaller than 100 μΐ . Essentially all pores may have a pore size below

100 μΐ . The porous body 24 may have a porosity larger than 20 %, in particular larger than 30 % or even larger than 40 %. The porosity may be below 80 %, in particular below 70%, or even below 60 %.

The porous body 24 may have a sandwich structure with multiple porous layers. At least one of its porosity and its mean pore size may show a gradient, e.g. in axial direction (with the cartridge reference axis 23 being perpendicular to the major surface of the porous body 24). Also the porosity may be lower at the radial edge of the porous body 24. In the illustrated embodiment, both major surfaces of the porous body 24 are covered by sheets 25,26 of liquid-pervious material, e.g. made of non-woven fabric. These sheets 25,26 capture any particles that detach themselves from the porous body 24. The active material can thus be bound more loosely, e.g. by only slightly compacting the porous body 24 during manufacturing or using a smaller amount of binder. The sheets 25,26 also help counter abrasion when the porous body 24 is being handled during manufacturing. In alternative embodiments of the cartridge 2, one or both of the sheets 25,26, in particular an interior sheet 26, may be dispensed with.

The porous body 24, and thus also the second housing component 22 overall, has a planar shape, with a thickness about an order of magnitude smaller than its diameter. The ratio of the thickness to the largest lateral dimension (from edge to edge) may be in the range of 7-12, for example. Since the first housing component 21 has an essentially circular cross-section (perpendicular to the cartridge reference axis 23), the second housing component 22 and porous body 24 are essentially discshaped in the illustrated example.

The second housing component 22 is stiff enough to be dimensionally stable. It is self-supporting and also stiff enough to carry the remainder of the cartridge 2 when the second housing component 22 is held at its edge in the cartridge seat in an otherwise unsupported arrangement. Furthermore, the second housing component 22 has a lower deformation under load, in at least the radial direction, than the first housing compo- nent 21. The first housing component 21 is thus reinforced by the second housing component.

The first housing component 21 is obtainable by thermoforming from a plastic sheet, e.g. from a sheet having a thickness of between 0.5 and 1.5 mm. In this process, the sheet is heated, stretched and cooled, resulting in specific characteristics including a varying wall thickness, e.g. in a range of between 0.2 and 0.8 mm, and a much lower wall thickness than alternatives such as injection-moulding. The wall of the first hous- ing component 21 is impervious to liquid.

The first housing component 21 may alternatively be formed using an alternative technique for moulding plastic parts, including injection- moulding, blow moulding and rotational moulding, for example. Injection moulding allows for the provision of alternative mechanical interfac- es for holding the cartridge 2 in sealed relation to an outlet of the funnel 3, e.g. a bayonet coupling.

The first housing component 21 will generally be made of a thermoplastic polymer material with optional additives. This may be a crystalline polymer. Examples of suitable polymers include polystyrene, PMMA (poly(methyl methacrylate), ABS (Acrylonitrile butadiene styrene), polycarbonate, PVC (polyvinyl chloride, LDPE (low-density polyethylene), HDPE (high-density polyethylene), PP (polypropylene), copolymer PP (PE copolymerised with PP) and cellulose acetate. A blend of polymers may also be used. The wall of the first housing component 21 includes a portion forming a side wall section 27, closed on itself about the cartridge reference axis 23 and a contiguous portion forming a base wall section 28 into which the side wall section 27 transitions at an axial end of the first housing component 21. Both wall sections 27,28 are integral parts of a single monolithic component made in one piece. The first housing component 21 has a mouth 29 (Fig. 6) at an opposite axial end to the base wall section 28. The first housing component 21 is thus essentially beaker-shaped.

The base wall section 28 is provided with an indentation 30 into an inte- rior of the first housing component 21, i.e. recessed with respect to the axial end of the first housing component 21, seen from its exterior. An aperture 31 is formed at a bottom end of the indentation 30. This aperture 31 is for forming a liquid-pervious window, in the example an inlet window, together with a further liquid-pervious component 32 for retain- ing particles above a certain size. The further liquid-pervious component may be a mesh, e.g. made of woven fabric or in the shape of a form- stable lattice, a piece of non-woven fabric, a screen, a sieve, a porous body or a laminate of one or more of these, for example. In the illustrated embodiment, the further liquid-pervious component is bonded to an interior surface section 33 (Fig. 6) of the base wall section 28 surrounding the aperture, e.g. by means of an adhesive or ultrasonic or thermal welding. The further liquid-pervious component 32 may be made of the same material as the first housing component 21, though structured differently in order to allow the liquid to pass through it. In the illustrated embodiment, the indentation 30 and the aperture 31 are centred on the cartridge reference axis 23 and have a rotationally symmetric shape. This makes the flow of liquid through the cartridge 2 more uniform. In alternative embodiments, one or more apertures may be provided in the sides of the indentation 30, each covered by a liquid- pervious component for retaining particles above a certain size.

Because the further liquid-pervious component 32 is joined to an interior surface section 33 of the base wall section 28 surrounding the aperture, an interior space portion 34 surrounding the indentation 30 is accessible to the encapsulated matter 19 when the first housing component 21 is oriented with the mouth 29 facing upwards. Because the interior surface section 33 is the interior surface of a section of the base wall section 28 that is planar, in contrast to the frusto-conical adjacent section defining the indentation 30, bonding of the further liquid-pervious component 32 to the first housing component 21 is facilitated.

In the illustrated embodiment, a step 35 is defined in the side wall section 27. The lateral dimension of the side wall section 27 increases at this step 35. A socket is thereby formed in the interior of the first hous- ing component 21, in which socket the second housing component 22 is received to close the mouth 29 of the first housing component 21 and define the interior space 20 for accommodating the liquid treatment medium. Thus, in the illustrated embodiment, the step 35 extends along the entire circumference of the first housing component 21. In an alter- native embodiment, discrete steps are defined at a particular axial position, so that no socket is defined at that positon and the second housing component 22 is otherwise joined to the first housing component 21.

The step 35 allows multiple first housing components 21 to be produced and stacked for storage or transport such that they are easily removed from such a stack 36. The side wall section 27 has a frusto-conical shape from the step 35 to the base wall section 28, being at a slight angle to the cartridge reference axis 23. This makes it easier to form the first housing component. The axial position of the step 35 relative to an axial end opposite the axial end at which the base well section 28 is located is selected in dependence on the angle of inclination, so as to provide a desired clearance between an exterior surface of the side wall section 27 of the first housing component 21 and an interior surface of the side wall section 27' of a first housing component 2 supporting the first housing component 21 in the stack 36. In the illustrated embodiment, as mentioned, the step 35 extends along the entire circumference of the first housing component 21, so that the side wall section 27 flares outwards to define a circumferential surface section 37 (Fig. 7) facing away from the base wall section 28. An edge section of a (major) surface of the second housing component 22 facing inwards, i.e. towards the base wall section 28, is placed against the circumferential surface section 37. The first housing component 21 and the second housing component 22 may be bonded together at the interface between the circumferential surface section 37 and the edge section of the surface of the second housing component 22. There can thus be a clearance due to tolerances between a lateral surface 38 (Fig. 11) of the second housing component 22 and an interior surface of the first housing component 21. Also, the radially extending section of the side wall section 27 at the step 35 allows for tools (clamps, sonotrodes or the like) to be applied to facilitate the formation of the bond.

Furthermore, the step 35 defines the axial dimension (i.e. the height) of the interior space 20 enclosed by the first housing component 21 and the second housing component 22 relatively well. It can thus be ensured that the encapsulated matter 19 extends to a level of the

aperture 31, in use.

It is noted that the first housing component 21 also includes a flange 39, which is due to the thermoforming process. This flange 39 forms a laterally protruding rim at an opposite axial end of the first housing component 21 to the axial end at which the base wall section 28 is provided. At this axial position, the side wall section thus also flares outwards to define a second circumferential surface section 40 (Fig. 7) facing away from the base wall section 28. In embodiments in which the step 35 is omitted, the edge section of the surface of the second housing component 22 facing inwards, i.e. towards the base wall section 28 is placed against the circumferential surface section 40 defined by the flange 39. Again, a bond may be formed between the first housing component 21 and the second housing component 22 at the interface between the two surface sections. This may be an adhesive bond or a bond formed by thermal or ultrasonic welding. In case the binder of the porous body 24 and the material of the first housing component 21 are compatible, e.g. the same, a simple thermal seal may be formed at the interface.

The flange 39 has a thickness approximately equal to the thickness of the sheet from which the first housing component 21 is manufactured. The side wall section 27 has a lower wall thickness as a result of the differential stretching process by which the first housing component 21 is formed. In alternative embodiments, the wall thickness of the first housing component 21 may be essentially uniform.

The encapsulated matter 19 is dimensionally unstable, meaning it has no fixed shape as a collective. It may be reticulated matter, i.e. loosely bound granular or fibrous matter. In the illustrated embodiment, it is loose matter, e.g. in granular form (e.g. beads, granules and/or powder). For more efficient use of the available space and because the porous body 24 already includes activated carbon, the encapsulated mat- ter 19 may include less than 10 wt.-% of activated carbon or at most trace amounts of activated carbon (e.g. only activated carbon that has become detached from the porous body 24). The remainder may be ion exchange resin. The ion exchange resin may be cation exchange resin, e.g. weakly acidic cation exchange resin. At least in a state prior to con- tact with liquid, the majority (in terms of the available treatment capacity as defined e.g. by DIN 54403) of the ion exchange resin may be in the hydrogen form. A minority may be loaded with one or more other cation species such as potassium, sodium, magnesium or lithium, to regulate the pH of the treated liquid. In an embodiment, the encapsulated matter 19 is loose matter consisting of only a single material. This means that the cartridge 2 is easier to recycle, since the encapsulated matter need not be separated into its constituent fractions. Moreover, no mixing or weighing of constituents is required to prepare the encapsulated matter. This in turn means that a subsequent complete or partial sterilisation step can be dispensed with without diminishing the suitability of the cartridge 2 for treating potable liquids.

A simplified method and assembly line for manufacturing the cartridge 2 includes a manufacturing line 41 for manufacturing the second housing component 22 as one of two parallel sub-assembly lines. The other includes a thermoforming station 42, followed by a trimming station 43. The first housing components 21 are formed from a sheet or web of plastic material at the thermoforming station. Here, the material is heated to its forming temperature and mechanically forced against a mould (not shown). The actual forming may include drape forming, vacuum forming, matched mould forming, diaphragm forming or pressure forming. The first housing components 21 are separated from the remainder of the sheet (also referred to as the edge trim or skeleton) at the trimming station 43, e.g. by compression cutting (also referred to as die cutting), shear cutting, abrasive cutting, brittle tensile cutting or thermal cutting, e.g. using a laser. The aperture 31 may be formed in the same process. In an embodiment, the trimming station 43 is part of the thermoforming station 42 and the separation of the first housing component 21 from the remainder of the sheet takes place in the mould.

In an alternative embodiment, the thermoforming station 42 and the trimming station 43 are replaced by a single moulding station for producing the first housing component 21. Alternatively, there may be an additional station for producing the aperture 31. Such alternative stations may be situated off-site, so that they are not part of the same assembly line.

In a next station 44, the further liquid-pervious component 32 is joined, e.g. bonded, to the first housing component 21. The result is a beaker- shaped housing component that can be filled with loose matter including one or more liquid treatment media . This is done at a filling station 45, at which sterile granular matter is aseptically poured into the beaker through the mouth 29. The volume of matter 19 poured in is less than the volume of the interior chamber formed by the first housing compo- nent 21 and the second housing component 22, such that, when the cartridge is turned over, the fill height h (Fig. 10) is at or above the level of the aperture 31 at least when the encapsulated matter has contacted the liquid to be treated (and thereby possibly swollen). As a consequence, the encapsulated matter 19 is also below the level of the step 35 when the filled beaker leaves the filling station 45. This makes it unlikely that any particles are trapped between the second housing component 22 and the circumferential surface section 37.

The second housing component 22 is joined to the first housing component to encapsulate the encapsulated matter at a next station 46. Alt- hough the example of bonding has been used for the step carried out at this station 46, purely mechanical joining techniques such as folding or the forming of a bead may be used instead.

The manufacturing line 41 for manufacturing the second housing component 22 includes a main endless belt 47 on support drums 48,49, which at least one is driven by a motor. A device 50 for depositing a layer of particulate and/or fibrous material including at least a binder onto a lower fabric web 51 is provided. The material may be deposited in dry form or sprayed on, for example. The lower fabric web 51 may be a web of non-woven textile material and is unwound from a first reel 52. A doctor blade 53 sets the thickness of the layer. An upper fabric web 54 is unwound from a second reel 55. The resulting layered structure is then heated in a double-belt press 56 to a temperature higher than the melting point of the binder. The double-belt press 56 is used to improve the transfer of heat. It applies only minimal pressure, e.g. below

5000 Pa.

A cutting device 57 is arranged to cut plates 58 from the layered structure emerging from the double-belt press 56. Each plate 58 is then transferred to a separating apparatus 59 for separating the second housing components 22 from a remainder of the plate 58. Die-cutting or laser cutting may be used, for example.

Because the second housing component 22 includes the porous body 24, has a relatively uniform thickness and extends substantially across the entire area of the mouth 29, a uniform back-pressure is created, in use. This helps prevent channel-forming in the encapsulated matter 19.

Any trapped air or gas created in the liquid treatment process is collected in the interior space portion 34 above the level of the aperture 31, in use. There is therefore no need for venting apertures. The wall of the first housing component 21 is therefore closed, except for the mouth 29 and the aperture 31, which are closed by the respective liquid-pervious components 22,32. There is therefore no need to provide gratings or small through-going channels in the wall defining the first housing component 21. The invention is not limited to the embodiments described above, which may be varied within the scope of the accompanying claims. The first housing component 21 may, for example, be obtained by twin-sheet forming. The fabric coverings 25,26 may be applied to the porous body 24 after it has been produced in the separating apparatus 59, instead of being formed from the lower and upper fabric webs 51,54.

In an alternative embodiment, the liquid treatment system includes a suction pump for drawing liquid from a container forming a reservoir of liquid to be treated through an outlet in which a seat for the replaceable liquid treatment system is provided. In yet another embodiment, a device for increasing the pressure in the container forming the reservoir of liquid to be treated is provided. Such liquid treatment systems are thus not purely gravity-driven. They may be of use where the liquid treatment cartridge includes a membrane filtration module as a liquid treatment part, for example.

Where reference has been made to a liquid treatment medium, this may include one or more media for the treatment of liquid in a diffusive pro- cess, including elution and sorption (ion exchange being considered an example of sorption for present purposes). Alternatives or additions to ion exchange materials include activated aluminium, zeolites, KDF (an alloy of copper and zinc), amongst others. These materials may also be incorporated into the porous body 24.

List of reference numerals

1 liquid treatment system

2 liquid treatment cartridge

3 funnel

4 jug

5 jug lid

6 closure part

7 pivotable cover part

8 spout

9 ledge

10 sleeve

11 system reference axis

12 receiving part

13 mounting ring

14 sealing element

15 threaded section

16 screw thread

17 mounting ring projections

18 lip

19 encapsulated matter

20 interior space

21 first housing component

22 second housing component

23 cartridge reference axis

24 porous body

25 exterior fabric covering

26 interior fabric covering

27 side wall section

28 base wall section 29 - mouth

30 - indentation

31 - aperture

32 - liquid-pervious component

33 - surrounding interior surface section

34 - interior space portion

35 - step

36 - stack

37 - circumferential surface section

38 - lateral surface

39 - flange

40 - second circumferential surface section

41 - pervious component manufacturing line

42 - thermoforming station

43 - trimming station

44 - bonding station

45 - filling station

46 - joining station

47 - main endless belt

48 - first support drum

49 - second support drum

50 - depositing device

51 - lower fabric web

52 - first reel

53 - doctor blade

54 - upper fabric web

55 - second reel

56 - double belt press

57 - cutting device

58 - plate separating apparatus

Claims

Liquid treatment cartridge, including

a housing and

a quantity of dimensionally unstable matter (19) forming at least one liquid treatment medium, encapsulated in an interior space (20) of the housing,

wherein the housing includes a first housing component (21) and a second housing component (22), distinct from the first housing component (21),

wherein the first housing component (21) includes a liquid- impervious side wall section (27), closed on itself about an axis (23), and a liquid-impervious base wall section (28) at an axial end of the housing,

wherein the base wall section (28) includes an

indentation (30) into the interior space (20),

wherein the indentation (30) is provided with at least one liquid-pervious window for retaining the encapsulated matter (19), wherein the interior space (20) includes a portion (34) that surrounds the indentation (30) and is accessible to the encapsulated matter (19), and

wherein the second housing component (22) is joined to the first housing component (21) at an axial position on an opposite side of an interior end of the indentation (30) to the axial end of the housing at which the base wall section (28) is located, characterised in that

the encapsulated matter (19) extends to a level enabling it to contact at least part of the liquid-pervious window in an orientation of the liquid treatment cartridge in which the second housing com- ponent (22) is situated at a lower level than the base wall section (28).

Liquid treatment cartridge according to claim 1,

wherein the liquid-pervious window is provided at an interior end of the indentation (30).

Liquid treatment cartridge according to claim 1 or 2,

wherein the liquid-pervious window lies essentially in a plane.

Liquid treatment cartridge according to any one of the preceding claims,

wherein a section of the base wall section (28) defines the indentation (30) and is provided with an aperture (31) covered by a liquid-pervious component (32) distinct from the base wall section (28) and covering the aperture (31) to form the liquid-pervious window.

Liquid treatment cartridge according to claim 4,

wherein the liquid-pervious component (32) is joined, e.g. bonded, around the aperture (31) to the section of the base wall section (28) defining the indentation (30).

Liquid treatment cartridge according to any one of the preceding claims,

wherein the base wall section (28) and the side wall

section (27) are integral parts of a wall defining the first housing component (21).

7. Liquid treatment cartridge according to any one of the preceding claims,

wherein the axis (23) is a central axis of the housing, and wherein the liquid-pervious window is centred on the ax- is (23).

8. Liquid treatment cartridge according to any one of the preceding claims,

wherein the second housing component (22) is a liquid- pervious housing component.

9. Liquid treatment cartridge according to claim 8,

wherein the second housing component (22) includes a liquid-pervious porous body (24).

10. Liquid treatment cartridge according to claim 9,

wherein the porous body (24) is made of bonded matter, e.g. bonded granular matter.

11. Liquid treatment cartridge according to any one of the preceding claims,

wherein the encapsulated matter (19) has a volume smaller than a volume of the interior space (20).

12. Liquid treatment system, including:

a container (3) for forming a reservoir of liquid to be treated; a liquid treatment cartridge (2) according to any one of the preceding claims; and

a seat for receiving the liquid treatment cartridge (2), located at an outlet of the container (3) and arranged to hold the liquid treatment cartridge (2) in a sealed relation to the outlet.

13. Liquid treatment system according to claim 12,

wherein the seat is arranged to hold the liquid treatment cartridge (2) in an orientation in which the liquid-pervious window forms an inlet of the liquid treatment cartridge (2).

14. Use of a liquid treatment cartridge according to any one of

claims 1-11 in a throughflow mode, such that the liquid-pervious window forms an inlet.

Method of manufacturing a liquid treatment cartridge, including : providing a first housing component (21), a second housing component (22) and a quantity of dimensionally unstable

matter (19) forming at least one liquid treatment medium,

wherein the first housing component (21) includes a liquid- impervious side wall section (27), closed on itself about an axis (23), and a liquid-impervious base wall section (28) at an axial end,

wherein the base wall section (28) includes an

indentation (30) into an interior space (20) surrounded by the side wall section (27),

wherein the interior space (20) includes a portion (34) that surrounds the indentation (30) and is accessible to the dimension- ally unstable matter (19), and

wherein the indentation (30) is provided with at least one liquid-pervious window for retaining the dimensionally unstable matter (19);

at least partially filling the interior space (20) with the dimensionally unstable matter (19); and

joining the second housing component (22) to the first housing component (21) at an axial position on an opposite side of an interior end of the indentation (30) to the axial end at which the base wall section (28) is located to encapsulate the matter (19), characterised in that

the interior space (20) is filled with an amount of matter (19) such that, in an orientation of the liquid treatment cartridge in which the second housing component (22) is situated at a lower level than the base wall section (28), the encapsulated matter (19) extends to a level enabling it to contact at least part of the liquid- pervious window.