Description

The invention relates to a liquid treatment cartridge, including :

at least one liquid treatment part; and

a housing encapsulating the liquid treatment part, the housing including a liquid-pervious housing component and a main housing compo- nent,

wherein the main housing component is defined by a wall, impervious to liquid, of which a portion forms a side wall section of the housing and a portion forms a base wall section of the housing,

wherein the main housing component has a mouth at an opposite end to the base wall section, and

wherein at least one aperture is formed in the wall of the main housing component, in which aperture a liquid-pervious window is formed,

wherein the liquid-pervious housing component is joined to the main housing component to close the mouth and encapsulate the liquid treatment part.

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

providing a liquid-pervious housing component and a main housing component,

wherein the main housing component is defined by a wall, impervious to liquid, of which a portion forms a side wall section of the housing and a portion forms a base wall section of the housing,

wherein the main housing component has a mouth at an opposite end to the base wall section, and

wherein at least one aperture forming a liquid-pervious window is formed in the wall of the main housing component,

the method including:

arranging a liquid treatment part, to which the liquid-pervious window and the liquid-pervious housing component are impervious, in an interior space defined by the main housing component; and

combining the liquid-pervious housing component with the main housing component to close the mouth and encapsulate the liquid treatment part.

WO 2012/084769 Al discloses a container comprising walls, which com- prise a side wall and a first end wall. The side wall and first end wall are configured as a single component part and define a container interior. The first end wall encloses an angle to a longitudinal axis of the container, so that the first end wall is provided with a conical section, in which a liquid-pervious section is situated. The container interior is closed by a second end wall. The second end wall is configured as a sintered filter body, which is plate-shaped and forms capillaries. In an embodiment, the container is configured as a cartridge, to which end it comprises holding means and sealing means. The holding means are formed as integral parts of the side wall. The component part comprising the side wall, the first end wall and the holding means is relatively expensive to manufacture, both in terms of the amount of material required to manufacture it and in terms of the tooling. It is also relatively difficult to recycle, since it is difficult to break open the component part.

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 cartridge that allow the cartridge to have a relatively inexpensive housing that is relatively easy to recycle. This object is achieved according to a first aspect by the liquid treatment cartridge according to the invention, which is characterised in that the main housing component is a thermoformed component.

For the purposes of the present invention, the term thermoforming refers to a method for preparing a shaped component from a sheet or film. In thermoforming, the sheet, film, etc. may be heated, e.g. to its melting or softening point or trajectory, stretched of or into a mould and then cooled, e.g. in the mould. The formed main housing component may then be trimmed from the thermoformed sheet, which may also take place in the mould. Thermoforming may include vacuum forming, pres- sure forming, twin-sheet forming, drape forming, free blowing, simple sheet bending and the like.

Thermoformed parts have relatively large surface-to-thickness ratios compared to moulded parts formed by other techniques such as blow moulding, injection-moulding or rotational moulding, e.g. above

100,000: 1. The use of a one-sided mould will generally also result in a varying wall thickness, with a rim at an axial end of the main housing component having the highest wall thickness. All this means that the thermoformed main housing component has recognisably different char ^¬ acteristics due to being thermoformed.

The relatively thin wall means that the amount of material needed to manufacture the main housing component is relatively low and that the cartridge housing is easily broached to remove the liquid treatment part in a recycling process. The main housing component is defined by a wall, impervious to liquid, of which a portion forms a side wall section of the housing and a portion forms a base wall section of the housing, and the main housing component has a mouth at an opposite end to the base wall section. Thus, the main housing component is essentially beaker- shaped, making it suitable for being manufactured in a thermoforming process. Manufacturability may be improved if at least an axial section (relative to a reference axis extending from the base wall section to the mouth) of the side wall section is frusto-conical in shape. In any event, the side wall section may have progressively increasing lateral dimen ^¬ sions in the axial direction towards the mouth, to allow for the use of a one-sided mould. This simplifies tooling. The cross-sectional shape, with the cross-sectional plane perpendicular to the axis, may be circular, oval or polygonal. An embodiment with a rounded cross-section is rela- tively easy to manufacture with a thin wall.

The liquid treatment cartridge includes at least one liquid treatment part, which is encapsulated by the housing. The at least one liquid treatment part may in particular include at least one liquid treatment medium including at least one filtration medium. It may include a mem- brane filtration module and/or a physicochemically active filtration medi ^¬ um, or more generally a medium for the treatment of liquid in a diffusive process, including sorption, e.g. ion exchange, and elution. The liquid treatment part may also include a pleated filter made of non-woven fab ^¬ ric. The liquid treatment cartridge is a throughflow liquid treatment cartridge, having at least one liquid-pervious inlet window and at least one liquid-pervious outlet window, each suitable for retaining the liquid treatment part, in particular any loose matter comprised therein. The liquid-pervious housing component may form one of the liquid-pervious inlet and outlet windows and the liquid-pervious window in the aperture of the main housing component the other. The wall of the main housing component is otherwise impervious to the liquid to be treated, so that shortcuts are prevented. The liquid is forced to flow through the liquid treatment part. This distinguishes the cartridge from thermoformed cartridges made entirely from liquid-pervious sheet material. Moreover, although provided with a relatively thin wall, the main housing component may be self-supporting. It thus retains its shape, as opposed to filter bags. The liquid-pervious housing component may be a self-supporting housing component. The liquid-pervious housing component may be stiff enough to support a remainder of the liquid treatment cartridge when the liquid- pervious housing component is held at its edge.

The liquid-pervious housing component may be a body with trough-going channels, e.g. a perforated planar body or moulded grating, or it may include a mesh. Examples include a layer of non-woven or woven fabric or a structure including multiple such layers.

The liquid-pervious housing component is joined to the main housing component to close the mouth and encapsulate the liquid treatment part. The liquid-pervious housing component may be joined to the main housing component at the mouth, i.e. at the axial end of the main housing component opposite the base wall section, or at a position somewhat set back from that axial end in axial direction. A simple housing is obtained if the mouth is closed only by the liquid-pervious housing component. The wall of the main housing component and the liquid-pervious housi ng component may in pa rticular present exterior surfaces of the l iquid treatment ca rtridge, as wel l as interior surfaces directly bounding a n in- terior space in which the l iquid treatment part is arranged .

In an embodiment, the liquid-pervious housi ng component i ncludes a po ^¬ rous body.

The porous body is itself liquid-pervious. When included in the liquid- pervious outlet window of the liquid treatment cartridge, the porous body functions as a depth fi lter. Thus, the liquid treatment part can in ^¬ clude relatively fine pa rticles or fibres that form a liquid treatment medi ^¬ um . Such particles or fibres may be loose or only loosely bound and stil l be filtered from the l iquid relatively effectively and thus retained i n the liquid treatment cartridge . A depth fi lter a lso does not clog easily. This al lows the flow rates through the liquid treatment cartridge to rema in relatively constant over the lifetime of the liquid treatment cartridge. The porous body is relatively easy to manufacture in a form that is self- supporting and stiff enough to support a remai nder of the l iquid treat ^¬ ment cartridge such that the porous body does not sag under the load of the rema inder of the liquid treatment ca rtridge. Thus, a cartridge seat for the cartridge need not include a lattice or gril le for supporting the cartridge.

In a variant of this embodiment, the porous body extends lateral ly across at least a n entire area defi ned by the side wal l section and closed by the l iquid-pervious housing component.

This embodi ment is relatively simple, in that frames for multi ple porous bodies need not be provided . The l iquid-pervious housing component in effect forms a closure part that closes an interior of the main housing component at an opposite end to the base wall section. In use, the liquid-pervious housing component may be arranged to form an outlet window. In particular when the porous body has relatively uniform proper- ties in lateral direction, including uniform flow resistance, a uniform back pressure can be created. Where the encapsulated liquid treatment part includes a bed of loose matter, channelling is thus largely prevented.

In a variant of the embodiment in which the liquid-pervious housing component includes a porous body, 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 includes particles and powder and results in point bonds that form rela- tively 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 liquid-pervious housing component includes a porous body, the liquid-pervious 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 abra- sion, as well as trapping any splinters that have become detached from the porous body.

In a variant of the embodiment in which the liquid-pervious housing component includes a porous body, the liquid-pervious housing compo- nent is a planar liquid-pervious housing component.

The porous body may also be a planar porous body. The resulting liquid-pervious housing component provides a relatively uniform backpressure. Moreover, it can be separated from a plate or sheet of porous material, rather than being individually moulded, for example. Further- more a flat major surface is relatively easy to bond to the main housing component, e.g. to a flange thereof, at the edge of the flat major surface.

In an embodiment, the liquid-pervious housing component is dimension- ally stable. This means that it has a fixed shape under load, being self-supporting. The liquid-pervious 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 extend- ing across that opening to support the cartridge. It suffices to hold the cartridge, in particular the liquid-pervious housing component, at an edge.

In an embodiment of the liquid treatment cartridge, the liquid-pervious housing component includes at least one medium for physicochemical treatment of the liquid, e.g. a medium for treatment of liquid by sorption, e.g. activated carbon. The liquid-pervious housing component thus increases the treatment ca ^¬ pacity of the liquid treatment cartridge, so that the liquid treatment part can be more compact or provide a larger treatment capacity. Where the medium is activated carbon, a relatively compact cartridge can be pro- vided, because a bed of gra nular or fibrous activated carbon is much more voluminous than bound activated carbon with the same treatment capacity. The space i nside the liquid treatment cartridge ca n thus be used for other liquid treatment media, such as ion exchange materia ls.

In an embodiment, the encapsulated l iquid treatment part incl udes di- mensional ly unstable matter formi ng at least one liquid treatment medi ^¬ um, e .g . for physicochemical treatment of the liquid .

The liquid treatment pa rt need not consist exclusively of dimensiona lly unsta ble matter. The di mensionally unstable matter has no fixed shape as a col lective. Instead the col lective shape is being determined by the main housing component. The encapsulated matter may i ncl ude loose matter, which may be granular and/or fibrous matter. Such matter may be relatively fine, presenti ng a relatively large surface area and forming relatively sma ll voids. The encapsulated matter may alternatively or ad ^¬ ditionally incl ude reticulated matter. The dimensionally unstable matter need comprise only a very low amount of bi nder, in the case of reticulat ^¬ ed matter, or none at all, i n the case of loose matter. Thus, there is more active matter ava ila ble for treati ng the liquid i n this embodiment. It also has a larger surface area, unobscured by binder, maki ng matter forming a liquid treatment medium for the treatment of liquid in a diffu- sive process more effective. Where the active matter formi ng a liquid treatment medi um swells on contact with the liquid, as is the case for ion excha nge resin, for example, the dimensional ly unstable matter can more easi ly conform to the shape of the i nterior of the liquid treatment cartridge. The di mensional ly unstable matter may be arranged in a n in- terior space of the liquid treatment cartridge in direct contact with an interior surface of the wall of the main housing component and an interior surface of the liquid-pervious housing component. Thus, there is no need to provide the encapsulated matter in a bag insides the interior space. The encapsulated matter can expand relatively unhindered and bypasses around it are avoided.

In a variant of this embodiment, the encapsulated matter is arranged to contact at least one, e.g. both, of the liquid-pervious window and the liquid-pervious housing component. This helps counter blocking of the liquid-pervious window and liquid- pervious housing component by trapped gas bubbles.

In a variant of the embodiment in which the encapsulated liquid treatment part includes dimensionally unstable matter forming at least one liquid treatment medium, e.g. for physicochemical treatment of the liq- uid, the encapsulated matter is arranged in an interior space defined by the main housing component and the liquid-pervious housing component, and the encapsulated matter has a volume smaller than a volume of the interior space.

This allows for the use of active matter including matter that swells rela- tively strongly on contact with liquid, such as ion exchange resin. Furthermore, additional empty space is available in the interior of the cartridge for gases. These include trapped air, but may also include gases generated in the liquid treatment process, e.g. C0 ₂ in the case of decar- bonisation. In a variant of the embodiment in which the encapsulated liquid treatment part includes dimensionally unstable matter forming at least one liquid treatment medium, e.g. for physicochemical treatment of the liquid, the liquid treatment cartridge includes at least one further liquid- pervious component for retaining the encapsulated matter, distinct from the main housing component and covering the aperture to form the liq- uid-pervious window.

The further liquid-pervious component prevents relatively small particles of the matter forming at least one liquid treatment medium from escaping from the liquid treatment cartridge. The further 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 interlaced strands, e.g. metal strands, in the manner of a sieve. The further liquid- pervious component may also include one or more layers of textile material, wherein a layer may be a layer of non-woven or of woven textile material . A relatively effective and simple variant uses a layer of non- woven textile material, i.e. fleece. The further liquid-pervious component may be joined to the main housing component mechanically, e.g. using fasteners or by means of a shape-lock. By providing a distinct further liquid-pervious component, the main housing component is easier to manufacture using thermoforming. A processing step to provide the wall of the main housing component with a liquid-pervious section for retaining relatively small particles is dispensed with. An intricate mould is also not required. Rather, it suffices to provide a relatively large aperture forming the edge of the liquid-pervious window. This aperture is then closed by the further liquid-pervious component. The aperture can be formed in a trimming step inherent to the thermoforming process, in which the main housing component is separated from the remainder of the sheet from which it is formed. In a variant of this embodiment, the further liquid-pervious component is joined, e.g. bonded, to the wall of the main housing component around the aperture.

Bonding includes adhesive bonding and welding, including ultrasonic and thermal welding, for example. Regardless of whether the further liquid- pervious component is bonded to the wall of the main housing component, the further liquid-pervious is fixed directly to the wall of the main housing component in this embodiment. A support frame or the like for pressing the further liquid-pervious component against the wall of the main housing component is not required. The wall directly supports the further liquid-pervious component. In the variant in which the further liquid-pervious component is bonded to the wall of the main housing component, a positive material joint is formed. This means that at least one material of which the main housing component is made and at least one material of which the further liquid-pervious component is made, and optionally an adhesive or filler, are coalesced to form the joint.

Bonding avoids the need for strengthening the main housing component, in particular for providing an increased wall thickness. It is thus more suited to the thermoformed main housing component. In an embodiment of the liquid treatment cartridge, the encapsulated liquid treatment part includes at least some ion exchange material and at most 20 % by weight, 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 avail- able 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 incorpo- rated into the liquid-pervious 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 re- cycled 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.

In an embodiment of the liquid treatment cartridge, the aperture is cen- tred on a central axis of the main housing component that extends from the base wall section to the mouth.

The central axis may be a body axis of the liquid treatment cartridge. In this embodiment, the flow of liquid through the cartridge is relatively uniformly in the axial direction. This is especially so if the fluid-pervious housing component has a relatively uniform thickness, measured in axial direction, and even more so if it includes a porous body with a uniform thickness that extends to cover the entire area of the mouth covered by the liquid-pervious housing component.

In an embodiment of the liquid treatment cartridge, the base wall sec- tion is provided with an indentation into an interior of the housing, and the aperture is provided in the indentation, e.g. at a bottom of the indentation. The indentation is into the interior of the housing, thus defining a concave section of the base wall section, viewed from the outside of the liquid treatment cartridge. A section of the interior of the housing surrounding the indentation is thus provided. Where the liquid-pervious window forms the liquid inlet window of the cartridge, in use, this surrounding space can be left empty to allow gas (e.g. air or gas arising in the liquid treatment) to collect in the surrounding space. The gas will be above the level of the aperture, so that it cannot block the liquid- pervious window. A venting aperture in the wall of the main housing component is not required, which further improves the suitability of the main housing component for production by thermoforming. If the interior of the liquid treatment cartridge is filled with loose or reticulated matter, then the amount of this matter may be chosen such that its level is at or just above that of the liquid-pervious window, at least upon contact with the liquid to be treated. The encapsulated matter will contact the mesh or similar structure covering the aperture to form the liquid- pervious window. This further contributes to improving the flow of liquid into the liquid treatment cartridge.

In an embodiment of the liquid treatment cartridge, the side wall section is provided with at least one laterally protruding step along at least part of its circumference.

In this embodiment, there may be one step extending all around the circumference or multiple steps, e.g. at the same axial location. The variant with the step extending around the entire circumference is relatively easy to manufacture. At the or each step, the side wall section widens over a relatively short axial distance. Due to the type of mould used for thermoforming, it will not generally narrow again, seen in axial direction towards the mouth. The step allows the liquid treatment cartridge to be held in a cartridge seat without obstructing the flow of liquid in axial di- rection (with respect to a reference axis extending from the base wall section towards the mouth). Furthermore, multiple main housing components can be thermoformed and then stacked before being handled further in the process of manufacturing the liquid treatment cartridge. The step is provided between the base wall section and a rim at an opposite axial end of the main housing component. When stacked, the step or steps of the main housing component rest on the rim of the main housing component below it, such that there is a clearance between the exterior surface of the side wall section of the main housing component and the interior surface of the side wall section of the main housing component below it. To this end, the lateral dimension of the side wall section at the step exceeds an inside lateral dimension of the main housing component at the rim forming the axial end of the main housing component opposite the axial end at which the base wall section is pro- vided. This lateral dimension would be the diameter in the case of a main housing component with a circular cross-sectional shape. The axial location of the step is chosen in dependence on the angle of inclination of the side wall section between the step and the base wall section (with respect to the reference axis), such as to achieve the desired clearance. In an embodiment of the liquid treatment cartridge, the side wall section has a rim at an opposite end to the base wall section, and the liquid- pervious housing component is received within the main housing component with a lateral surface of the liquid-pervious housing component below a level of the rim. The edge of the lateral surface of the liquid-pervious 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 main housing component forms a kind of socket for receiving the liquid-pervious housing component. In this manner, the side wall section of the main housing component shields the liquid-pervious housing component. The liquid- pervious housing component can thus be relatively brittle. It may in particular consist mainly or exclusively of a relatively brittle porous body. Furthermore, the lateral surface of the liquid-pervious housing compo- nent may be liquid-pervious, with bypasses of liquid through this lateral surface being prevented by the side wall section of the main housing component and optionally by sealant provided between the lateral surface of the liquid-pervious housing component and the main housing component. This embodiment may also provide a cartridge with an aes- thetically pleasing appearance, even if the appearance of the lateral surface of the liquid-pervious 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, and an edge section of a surface of the liquid-pervious housing component facing in a direction of the base wall section 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 main 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 main housing component and located at an axial position between the mouth and the base wall section. In either case, the liquid- pervious housing component will have a relatively well-defined axial position with respect to the base well section. If the encapsulated liquid treatment part includes encapsulated loose or reticulated matter, the height of that matter, supported by either the base wall section or the liquid-pervious housing component in use, will be relatively well-defined. This also goes for any empty space provided for collecting gases or for allowing the encapsulated matter to expand. As a bonus effect, a cir- cumferentially 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 liquid-pervious housing component against the circumferential surface section of the main housing component even more tightly, thus also preventing bypasses be- tween the main housing component and the liquid-pervious housing component.

In a variant of this embodiment, a bond is formed between the main housing component and the liquid-pervious housing component at an interface between the circumferential surface section of the side wall sec- tion and the edge section of the surface of the liquid-pervious housing component.

Bonding includes adhesive bonding and welding, including ultrasonic and thermal welding, for example. At least one material of which the main housing component is made and at least one material of which the liq- uid-pervious housing component is made, and optionally an adhesive or filler, are coalesced to form the joint. The materials of the main housing component and the liquid-pervious-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, the main housing component and at least an exterior part of the liquid-pervious housing component comprise a common material, e.g. a thermoplastic material. This embodiment is easier to recycle. The thermoplastic material allows the liquid-pervious housing component and main housing component to be bonded without the use of adhesives or fillers.

In an embodiment, the liquid treatment cartridge is provided with a cir- cumferential rim protruding laterally with respect to a remainder of the side wall section.

This rim is formed in a trimming step of the thermoforming process. By leaving it in place, the manufacturing process is simplified. The rim may allow for easy stacking of main housing components at an intermediate stage in the manufacturing process of the cartridge, by supporting main 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. 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 the invention; 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 pressuris- ing 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.

A gravity-driven liquid treatment system further includes a vessel for collecting the treated liquid, wherein the container is arranged to be sus- pended 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 system, the container is provided with a sleeve extending from a bottom wall of the container and having a mouth at a level of the bottom wall of the container, and the seat is provided in the sleeve at a distance from the bottom wall of the container.

This embodiment is relatively convenient for the liquid treatment car- tridge with the thermoformed main housing component, because parts such as screw threads or lugs for forming a bayonet lock are difficult to form on the main housing component. Instead, the liquid treatment cartridge can simply be inserted into the sleeve and held in place axially such that liquid can only leave the sleeve by flowing through the liquid treatment cartridge.

In a variant of this embodiment, 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 the 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. There may at most be some untreated liquid in the sleeve between the sleeve and the liquid treatment cartridge.

In an embodiment of the liquid treatment system, the side wall section of the main housing component of the liquid treatment cartridge is pro- vided with a part protruding laterally with respect to a remainder of the side wall section along a circumference 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 with respect to an axis directed from the base wall section to the mouth of the main housing component.

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 a liquid treatment part including ion exchange material for softening, decarbonising or demineralising the mains drinking water and/or a liquid treatment part including a membrane filtration module and/or a pleated filter made of non-woven textile. 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.

Regardless of this potential for obtaining economies of scale, the seat need not obstruct the flow of liquid, because the protruding part is clamped. In particular, the liquid-pervious area of the liquid-pervious housing component can extend across the whole area of the mouth cov- ered by it. This provides for relatively uniform flow and relatively high rates of flow, even in a purely gravity-driven system.

According to another aspect, the invention provides for the use of a liquid treatment cartridge according to the invention to treat a liquid in a throughflow mode, such that the liquid-pervious housing component forms an outlet of the liquid treatment cartridge and the liquid-pervious window forms an inlet.

The main housing component may have a relatively low wall-thickness. The liquid-pervious housing component may be relatively stiff and thick- er, supporting the remainder of the liquid treatment cartridge without sagging, even if only supported at its edges. Relatively uniform flow is provided in this embodiment if a liquid-pervious area of the liquid- pervious housing component extends across the whole area of the mouth covered by the liquid-pervious housing component. This is enhanced if the liquid-pervious housing component is a planar liquid-pervious housing component. If it includes a planar porous body, then a relatively uniform back-pressure is created and the liquid-pervious housing component can act as a depth filter to retain any fine particulate matter encapsulated in the liquid treatment cartridge.

According to another aspect, the method of manufacturing a liquid treatment cartridge according to the invention is characterised in that the main housing component is a thermoformed component.

The method may include the actual step of thermoforming the main housing component. It uses relatively low amounts of material to manu- facture the main housing component and imposes minimal tooling requirements. A variant of the method includes manufacturing the liquid-pervious housing component, wherein manufacturing the liquid-pervious housing component includes manufacturing a liquid-pervious porous body.

The liquid-pervious housing component is relatively uniformly liquid- pervious, giving rise to relatively uniform flow characteristics.

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. Relatively uniform pore sizes are obtained, being determined essentially by the particle sizes used and how much the particulate matter is compacted. Point bonds are formed that leave a relatively large surface are available for contacting the liquid to be treated.

In a particular variant hereof, the liquid-pervious porous body is sepa- rated from a remainder of a sheet of bonded particulate matter.

This is a relatively efficient way of producing planar porous bodies, compared to moulding them individually. Separation may include shearing or laser-cutting, for example.

In an embodiment of the method, the main housing component is ther- moformed to provide the base wall section with an indentation into an interior of the housing, and the aperture is provided in the indentation, e.g. at the bottom of the indentation.

The aperture may be formed in the mould used to shape the main housing component, either simultaneously or subsequently. Thus, an embodiment of the method includes thermoforming the main housing component from a panel and separating the main housing component from a remainder of the panel, wherein the aperture is formed whilst separating the main housing component from the remainder of the panel, e.g. by shearing.

An embodiment of the method includes covering the aperture with at least one further liquid-pervious component prior to filling the main housing component with loose matter forming at least one liquid treatment medium. In this embodiment, the aperture may be relatively large, but the loose matter may be relatively fine. It suffices to provide an appropriately configured further liquid-pervious component. The further liquid- pervious component may for example include at least one layer of textile material, e.g. a non-woven textile material. For ease of manufacturing, the further liquid-pervious housing component may extend across and be bonded to an interior surface section of the base wall section surrounding the aperture. This interior surface section may be flat; indeed the section of the base wall section presenting this interior surface section may be planar. 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 replaceable 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 main housing component of the replaceable liquid treatment cartridge;

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

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

Fig. 8 is a cross-sectional view of the main housing component stacked on top of another main 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 car- tridge in its operative orientation;

Fig. H is a schematic cross-sectional view (not to scale) of a liquid- 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. 10.

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 cartridge 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. The housing includes a liquid-pervious housing component 20 and a main housing component 21. It is convenient to define a cartridge reference axis 22, substantially aligned with the system reference axis 11 when the cartridge 2 is correctly positioned in the cartridge seat.

The liquid-pervious housing component 20 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 liquid-pervious housing component 20 is of the type and configuration for which the cartridge seat is designed. The liquid-pervious housing component 20 is discshaped in the illustrated embodiment, because the main housing compo- nent has a circular cross-section. The liquid-pervious component includes a porous body 23 (Fig. 11). The porous body 23 is made of bonded matter, which includes a binder and at least one active material for physicochemical treatment of liquid. In particular, the matter in- eludes at least one sorbent, including specifically activated ca rbon . The bonded matter may be particulate matter, forming point-bonds that keep the porous body 23 together a nd define i nterstices forming the pores of the porous body. The bi nder particles may have a mean diameter larger tha n that of the particles of the active l iquid treatment materia l, so that the pore size is relatively large but the active material presents a rela ^¬ tively large surface area . The binder may be a thermoplastic binder. The melting point of the binder (determined usi ng differential sca nni ng calori metry) is at least 120° C, e .g . in the range of 120-150° C. The binder is thermally stable to at least 300° C. Suita ble binders incl ude ultra-high density polyethylene. Further details of manufacturing me ^¬ thods are provided i n StrauB, S., "Gesinterte Kunststoff-Formteile fiir die Fest-/Flussig-Filtration, Technische Mitteilungen, 8Ji (2), J uly 1992, pp . 100-104. Typically, the mean pore size (measured by determi ning the Mean Flow Path) in the majority of the porous body 23 wil l be larger tha n 2 μΐτι, in particular larger than 5 μΐ . The mean pore size wi ll generally be smaller than 100 μΐ . Essential ly all pores may have a pore size below

100 μΐ . The porous body 23 may have a porosity la rger than 20 %, i n particular la rger than 30 % or even larger than 40 % . The porosity may be below 80 %, i n particular below 70%, or even below 60 %.

The porous body 23 may have a sandwich structure with multi ple porous layers. At least one of its porosity and its mean pore size may show a gradient, e.g . i n axial direction (with the cartridge reference axis 22 be ^¬ ing perpendicular to the major surface of the porous body 23). Also the porosity may be lower at the radial edge of the porous body 23. In the illustrated embodiment, both major surfaces of the porous body 23 are covered by sheets 24,25 of liquid-pervious material, e.g. made of non-woven fabric. These sheets 24,25 capture any particles that detach themselves from the porous body 23. The active material can thus be bound more loosely, e.g. by only slightly compacting the porous body 23 during manufacturing or using a smaller amount of binder. The sheets 24,25 also help counter abrasion when the porous body 23 is being handled during manufacturing. In alternative embodiments of the cartridge 2, one or both of the sheets 24,25, in particular an interior sheet 25, may be dispensed with.

The porous body 23, and thus also the liquid-pervious housing component 20 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 main housing component 21 has an essentially circular cross-section (perpendicular to the cartridge reference axis 22), the liquid-pervious housing component 20 and porous body 23 are essentially disc-shaped in the illustrated example.

The liquid-pervious housing component 20 is stiff enough to be dimen- sionally stable. It is self-supporting and also stiff enough to carry the remainder of the cartridge 2 when the liquid-pervious housing component 20 is held at its edge in the cartridge seat in an otherwise unsupported arrangement. Furthermore, the liquid-pervious housing component 20 has a lower deformation under load, in at least the radial direc- tion, than the main housing component 21. The main housing component 21 is thus reinforced by the liquid-pervious housing component.

The main 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 main hous- ing component 21 is impervious to liquid.

The main 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), poly- carbonate, 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 main housing component 21 includes a portion forming a side wall section 26, closed on itself about the cartridge reference axis 22 and a contiguous portion forming a base wall section 27 into which the side wall section 26 transitions at an axial end of the main housing component 21. Both wall sections 26,27 are integral parts of a single monolithic component obtainable by thermoforming from a plastic sheet.

The main housing component 21 has a mouth 28 (Fig. 6) at an opposite axial end to the base wall section 27. The main housing component 21 is thus essentially beaker-shaped.

The base wall section 27 is provided with an indentation 29 into an inte- rior of the main housing component 21, i.e. recessed with respect to the axial end of the main housing component 21, seen from its exterior. An aperture 30 is formed at a bottom end of the indentation 29. This aper- ture 30 is for forming a liquid-pervious window, in the example an inlet window, together with a further liquid-pervious component 31 for retaining 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 an embodiment, the further liquid-pervious component is bonded to an interior surface section 32 (Fig. 6) of the base wall section 27 surrounding the aperture, e.g. by means of an adhesive or ultrasonic or thermal welding. The further liquid-pervious component 31 may be made of the same material as the main housing component 21, though structured differently in order to allow the liquid to pass through it.

In the illustrated embodiment, the indentation 29 and the aperture 30 are centred on the cartridge reference axis 22 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 29, each covered by a liquid- pervious component for retaining particles above a certain size. A single such component may cover more than one aperture. Because the further liquid-pervious component 31 is joined to an interior surface section 32 of the base wall section 27 surrounding the aperture, an interior space 33 surrounding the indentation 29 is accessible to liquid treatment medium in the form of loose matter when the main housing component 21 is oriented with the mouth 28 facing upwards. Be- cause the interior surface section 32 is the interior surface of a section of the base wall section 27 that is planar, in contrast to the frusto- conical adjacent section defining the indentation 29, bonding of the further liquid-pervious component 31 to the main housing component 21 is facilitated. In the illustrated embodiment, a step 34 is defined in the side wall section 26. The lateral dimension of the side wall section 26 increases at this step 34. A socket is thereby formed in the interior of the main housing component 21, in which socket the liquid-pervious housing com- ponent 20 is received to close the mouth 28 of the main housing component 21 and define an interior space for accommodating the liquid treatment medium. Thus, in the illustrated embodiment, the step 34 extends along the entire circumference of the main housing component 21. In an alternative embodiment, discrete steps are defined at a particular axial position, so that no socket is defined at that positon and the liquid- pervious housing component is otherwise joined to the main housing component 21.

The step 34 allows multiple main housing components 21 to be produced and stacked for storage or transport such that they are easily removed from such a stack 35. The side wall section 26 has a frusto-conical shape from the step 34 to the base wall section 27, being at a slight angle to the cartridge reference axis 22. This makes it easier to form the main housing component. The axial position of the step 34 relative to an axial end opposite the axial end at which the base well section 27 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 26 of the main housing component 21 and an interior surface of the side wall section 26' of a main housing component 2 supporting the main housing component 21 in the stack 35. In the illustrated embodiment, as mentioned, the step 34 extends along the entire circumference of the main housing component 21, so that the side wall section 26 flares outwards to define a circumferential surface section 36 (Fig. 7) facing away from the base wall section 27. An edge section of a (major) surface of the liquid-pervious housing component 20 facing inwards, i.e. towards the base wall section 27, is placed against the circumferential surface section 36. The main housing component 21 and the liquid-pervious housing component 20 may be bonded together at the interface between the circumferential surface section 36 and the edge section of the surface of the liquid-pervious housing component 20. There can thus be a clearance due to tolerances between a lateral surface 37 (Fig. 11) of the liquid-pervious housing component 20 and an interior surface of the main housing component 21. Also, the radially extending section of the side wall section 26 at the step 34 allows for tools (clamps, sonotrodes or the like) to be applied to facilitate the formation of the bond.

Furthermore, the step 34 defines the axial dimension (i.e. the height) of the interior space enclosed by the main housing component 21 and the liquid-pervious housing component relatively well. It can thus be en- sured that the encapsulated matter 19 extends to a level of the

aperture 30, in use.

It is noted that the main housing component 21 also includes a

flange 38, which is due to the thermoforming process. This flange 38 forms a laterally protruding rim at an opposite axial end of the main housing component 21 to the axial end at which the base wall section 27 is provided. At this axial position, the side wall section thus also flares outwards to define a second circumferential surface section 39 (Fig. 7) facing away from the base wall section 27. In embodiments in which the step 34 is omitted, the edge section of the surface of the liquid-pervious housing component 20 facing inwards, i.e. towards the base wall section 27 is placed against the circumferential surface section 39 defined by the flange 38. Again, a bond may be formed between the main housing component 21 and the liquid-pervious housing component 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 23 and the material of the main housing component 21 are compatible, e.g. the same, a simple thermal seal may be formed at the interface. The flange 38 has a thickness approximately equal to the thickness of the sheet from which the main housing component 21 is manufactured. The side wall section 26 has a lower wall thickness as a result of the differential stretching process by which the main housing component 21 is formed. Thus, the method used to manufacture the main housing com- ponent 21 is recognisable from the varying wall thickness, in particular where the flange 38 is formed, as well as the relatively low value of the wall thickness of the side wall section 26 (see Fig. 7). Residual stress may also characterise the main housing component 21 compared to, for example, injection-moulded cartridge housings. 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 po- rous body 23 already includes activated carbon, the encapsulated matter 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 23). 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 contact 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 40 for manufacturing the liquid-pervious housing component 20 as one of two parallel sub-assembly lines. The other includes a thermoforming station 41, followed by a trimming sta- tion 42. The main 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 main housing components 21 are separated from the remainder of the sheet (also referred to as the edge trim or skeleton) at the trimming station 42, 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 30 may be formed in the same process. In an embodiment, the trimming station 42 is part of the thermoforming station 41 and the separation of the main housing component 21 from the remainder of the sheet takes place in the mould. In a next station 43, the further liquid-pervious component 31 is joined, e.g. bonded, to the main 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 44, at which sterile granular matter is aseptically poured into the beaker through the mouth 28. The volume of matter 19 poured in is less than the volume of the interior chamber formed by the main housing component 21 and the liquid-pervious housing component 20, such that, when the cartridge is turned over, the fill height h (Fig. 10) is at or above the level of the aperture 30 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 34 when the filled beaker leaves the filling station 44. This makes it unlikely that any particles are trapped between the liquid-pervious housing component 20 and the circumferential surface section 36.

The liquid-pervious housing component 20 is joined to the main housing component to encapsulate the encapsulated matter at a next station 45. Although the example of bonding has been used for the step carried out at this station 45, purely mechanical joining techniques such as folding or the forming of a bead may be used instead.

The manufacturing line 40 for manufacturing the liquid-pervious housing component 20 includes a main endless belt 46 on support drums 47,48, which at least one is driven by a motor. A device 49 for depositing a layer of particulate and/or fibrous material including at least a binder onto a lower fabric web 50 is provided. The material may be deposited in dry form or sprayed on, for example. The lower fabric web 50 may be a web of non-woven textile material and is unwound from a first reel 51. A doctor blade 52 sets the thickness of the layer. An upper fabric web 53 is unwound from a second reel 54. The resulting layered struc- ture is then heated in a double-belt press 55 to a temperature higher than the melting point of the binder. The double-belt press 55 is used to improve the transfer of heat. It applies only minimal pressure, e.g. below 5000 Pa. A cutting device 56 is arranged to cut plates 57 from the layered structure emerging from the double-belt press 55. Each plate 57 is then transferred to a separating apparatus 58 for separating the liquid- pervious housing components 20 from a remainder of the plate 57. Die- cutting or laser cutting may be used, for example. Because the liquid-pervious housing component 20 includes the porous body 23, has a relatively uniform thickness and extends substantially across the entire area of the mouth 28, a uniform back-pressure is created, in use. This helps prevent channel-forming in the encapsulated matter 19. The cartridge 2 is relatively easy to recycle after use, because the thin wall of the main housing component 21 is relatively easily ruptured to remove the encapsulated matter 19.

The invention is not limited to the embodiments described above, which may be varied within the scope of the accompanying claims. The main housing component 21 may, for example, be obtained by twin-sheet forming. The fabric coverings 24,25 may be applied to the porous body 23 after it has been produced in the separating apparatus 58, instead of being formed from the lower and upper fabric webs 50,53.

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 treat- ment 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 process, 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 23.

List of reference numerals

1 liquid treatment system

2 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 liquid-pervious housing component

21 main housing component

22 cartridge reference axis

23 porous body

24 exterior fabric covering

25 interior fabric covering

26 side wall section

27 base wall section

28 mouth 29 - indentation

30 - aperture

31 - further liquid-pervious component

32 - surrounding interior surface section

33 - interior space surrounding indentation

34 - step

35 - stack

36 - circumferential surface section

37 - lateral surface

38 - flange

39 - second circumferential surface section

40 - liquid-pervious component manufacturing line

41 - thermoforming station

42 - trimming station

43 - bonding station

44 - filling station

45 - joining station

46 - main endless belt

47 - first support drum

48 - second support drum

49 - depositing device

50 - lower fabric web

51 - first reel

52 - doctor blade

53 - upper fabric web

54 - second reel

55 - double belt press

56 - cutting device

57 - plate separating apparatus