Abstract:
A filter unit for treating water, having a first plate-shaped filter element and at least one second plate-shaped filter element. The first and second filter elements are mutually spaced from each other and define an intermediate space. Each of the first arid second filter elements extends, with reference to a Cartesian coordinate system, along a first spatial axis to a considerably lesser extent than along the two remaining spatial axes such that the element has a layer thickness (ρ). Flow can take place through the first and second filter elements along a path that corresponds to the layer thickness.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to a filter unit for treating water, comprising: a first planar filter body; and at least one second planar filter body, wherein the first and the second filter bodies are arranged spaced apart from each other and delimit an intermediate space, and wherein each of the first and second filter bodies extends, with reference to a Cartesian coordinate system, over a considerably shorter distance along a first spatial axis than along the two remaining spatial axes, so that it has a layer thickness (ρ). 
         [0002]    The invention further relates to a container for treating water. 
         [0003]    The invention also relates to a use of a filter unit. 
       BACKGROUND OF THE INVENTION 
       [0004]    Although drinking water as taken from the local water network usually has a high quality in respect of its purity, it is not uncommon for it nevertheless to contain substances damaging to health, such as heavy metals or microorganisms. In order to remove these, various methods are known, for example the irradiation of the drinking water to be treated with UV radiation, which leads to an inactivation of the microorganisms. Furthermore, the use of activated carbon recommends itself, in order, for example, to remove microorganisms and heavy metals. An example of a treatment system for drinking water using activated carbon is shown in WO 2004/113232. 
         [0005]    Activated carbon in the form of a granulate is frequently used in the containers mentioned at the outset. The water to be treated is put into the container, runs through the bed of granulated activated carbon and then leaves the container again. The granules have the property that their particle size can be selected such that an effective treatment of the drinking water becomes possible. The smaller the particles used, the better is the treatment. However, it is not possible to prevent a small part of the activated carbon particles from escaping from the container and ending up in the treated water, which is undesired. The extent of egress of particles increases with decreasing particle size. 
         [0006]    Furthermore, U.S. Pat. No. 4,753,728 shows a altered, cylindrical filter body made of activated carbon, which is provided with an inner layer and an outer layer with different respective permeabilities. Due to the filter body&#39;s being sintered, egress of particles is prevented. However, the filter area is limited, so that the volume flow through the filter body is likewise limited. 
         [0007]    In comparison with coarser particles, the use of smaller particles permits the same treatment performance while using less raw material; at the same time, the required installation volume in the container decreases. As also described in WO 2004/113232, the escape of fine particles can be reduced by the particles&#39; being enveloped in a very fine-mesh fabric. However, finer particles cause a greater flow resistance, which is of disadvantage in particular in gravity-driven treatment systems. In particular, the time required to treat the drinking water thereby increases. 
         [0008]    U.S. Pat. No. 5,308,703 discloses an assembly for adsorption, which comprises at least two sheet absorbents which are arranged in layers so as to form a space between the adjacent sheets, each of the sheet-like adsorbents comprising a heat-conductive sheet and at least one adsorbent sheet containing an adsorbing agent and is arranged on at least one surface of the heat-conductive sheet in contact therewith. The adsorbing sheet is a sintered body made of activated carbon with a density of not less than 0.4 g/cm 3 . The heat-conductive sheet is a metal sheet. 
         [0009]    The fluid to be treated must flow past the sheet-like adsorbents, parallel to the latter. In particular where the spacing between the adjacent adsorbents is too large or the dimensions thereof parallel to the direction of flow are too small, complete treatment does not occur. 
       SUMMARY OF THE INVENTION 
       [0010]    It is an object underlying the invention to provide a filter unit of the type mentioned at the outset with a relatively effective action and a relatively high volume flow under given pressure conditions. 
         [0011]    According to a first aspect, the filter unit according to the invention is characterised in that flow can take place through the first and the second filter bodies along a path corresponding to the layer thickness. 
         [0012]    This path is relatively short. 
         [0013]    The volume flow {dot over (V)} through the filter unit can be defined as follows: 
         [0000]    
       
         
           
             
               V 
               . 
             
             = 
             
               
                 
                   k 
                   · 
                   Δ 
                 
                  
                 
                     
                 
                  
                 
                   p 
                   · 
                   A 
                 
               
               ρ 
             
           
         
       
     
         [0014]    Here, k is the permeability, Δp is the pressure difference between the pressure of the water at the entry face and the exit face of the filter unit, A is the filter area and ρ is the layer thickness. The reciprocal of the permeability constitutes the flow resistance through the filter unit. The filter area A is that area through which the water to be treated flows. 
         [0015]    The two variables permeability k and flow resistance 
         [0000]    
       
         
           
             1 
             k 
           
         
       
     
         [0000]    compare to one another analogously to electrical resistance and electrical conductivity. 
         [0016]    The volume flow {dot over (V)} through the filter unit decreases with increasing layer thickness ρ of the filter unit, while Δp in the case of a gravity-driven system is determined by the hydrostatic conditions in the container. In the case of a pressure-driven system, Δp is determined, for example, by the flow pressure in the water conducts. It follows from the above equation that both a reduction in the flow resistance 
         [0000]    
       
         
           
             1 
             k 
           
         
       
     
         [0000]    and an enlargement of the filter area A and a reduction in the layer thickness ρ bring about an increase in the volume flow {dot over (V)} through the filter unit. 
         [0017]    Here, “planar” is to be understood to mean a filter body which, with reference to a Cartesian coordinate system, extends over a considerably shorter distance along one spatial axis than along the two remaining spatial axes. In other words, the filter body has a low thickness or layer thickness and for example, can be shaped like a parallelepiped, a cube or a disc. The lower the layer thickness, the lower also is the flow resistance. Since the water to be treated consequently flows through the filter body along a relatively short path, the flow resistance can be kept low on account of the planar configuration; at the same time the filter area can be enlarged, so that the volume flow through the filter unit is increased. 
         [0018]    In one embodiment, flow can take place through the first and the second filter body in the direction of the intermediate space along a path corresponding to the layer thickness. 
         [0019]    The treated water therefore leaves the filter unit via the intermediate space. The water to be treated is supplied to the filter unit from two sides. 
         [0020]    In one embodiment, the planar filter bodies are sintered filter bodies. 
         [0021]    Sintering permits the production of stable filter bodies, which can also be manufactured in the shape of a plate. At least one of the filter bodies may consist essentially only of a sinterable material that is inert with respect to the water. Thus, a filter body can be manufactured with relatively fine pores. It can thereby take on a mechanical filtration function. Filter bodies with such small pores cannot be produced in an injection-moulding process or only with a very large effort. 
         [0022]    In one embodiment, the filter unit is configured in the form of a sandwich structure. 
         [0023]    The sandwich structure for treating water therefore comprises a first, in particular sintered, planar filter body and a second, in particular sintered, planar filter body, which are arranged spaced apart from each other and delimit an intermediate space. The sandwich structure can be produced before its installation in a container for treating water and subsequently be installed in the desired position. An outlet of this container can then be located in the intermediate space between the activated carbon filters, so that atmospheric pressure prevails here and a pressure gradient towards the intermediate space is generated. The water consequently flows in the direction of the intermediate space. In this configuration, too, the filter area is enlarged in that a unit volume of the water to be treated is able to flow through two filter bodies without the flow resistance increasing, which in turn further reduces the time required for the treatment. 
         [0024]    The intermediate space can be an empty space which, for example, is produced by means of spacers, such that the two filter bodies are arranged at a defined distance to each other. This produces an effect, in particular during the production, since the two filter bodies do not come into contact with each other during sintering and are not adhered to each other. 
         [0025]    In an embodiment, the sandwich structure comprises a cover layer for sealing off an end face of the filter body. 
         [0026]    The end face or the end faces, depending on the geometric shape of the filter body, are those faces which represent the smaller areas in the planar configuration of the filter body. In order to ensure a largely uniform level of treatment, the time needed by the water to flow through the activated carbon filter must be as uniform as possible. If the water enters into the activated carbon filter through the end or the ends, it needs a different time than if it enters via the filter areas. The cover layer prevents the penetration of the water via the end face and ensures that the water enters only via the filter areas. Thus, a uniform level of treatment is established. 
         [0027]    In one embodiment, the cover layer covers and seals off the intermediate space. 
         [0028]    Were the water able to enter directly into the intermediate space, it would not be treated. The cover layer ensures that the water can only reach the intermediate space after it has flowed through the filter bodies and thereby been treated. 
         [0029]    In an embodiment, a drainage layer is arranged in the intermediate space. In this way, it is possible to devise a sandwich structure, the stability of which is still higher than that of the embodiments described above. The layer thickness of the filter bodies can be reduced still further, whereby the raw material requirements decrease further. During the production of the sandwich structure, the drainage layer has the function of keeping the neighbouring filter bodies spaced apart. The drainage layer is formed from a material which on the one hand does not decompose during the sintering process and on the other hand does not lead to any appreciable increase in the flow resistance. 
         [0030]    The drainage layer may be an empty space or a sheet structure. An empty space can be produced, for example, by means of spacers, such that the two filter bodies are arranged at a defined distance to each other. 
         [0031]    In a variant of this embodiment, the drainage layer has a thickness, and the layer thickness is two to three times as large as the thickness. 
         [0032]    This ratio of the thickness of the intermediate space to the layer thickness has proven to be effective on the one hand for the required treatment time of the water and on the other hand for the stability of the sandwich structure. 
         [0033]    In an embodiment, the drainage layer is a sheet structure, in particular a textile sheet structure, more particularly a textile sheet structure made of a non-woven material, a knitted material or a woven material. 
         [0034]    A sheet structure is to be understood to mean any structure that comprises fibres of any desired type. In particular, the sheet structure is a textile sheet structure made of a non-woven material, knitted material or woven material. The sheet structure may comprise polyester or consist of polyester. Both non-woven materials and knitted materials or woven materials can be produced cost-effectively and are distinguished by good chemical and mechanical stability, in particular if they are permanently moist. This applies to a particular extent to non-woven materials, knitted materials and woven materials made of polyester. Furthermore, non-woven materials, knitted materials and woven materials can be provided with good permeability, so that they do not generate a high flow resistance. Polyester is not decomposed during a sintering process. 
         [0035]    In an embodiment, the sheet structure comprises fibres which are at least one of chemically and physically active. These may be activated carbon non-wovens or nano-aluminium fibres, which adsorb particles. Furthermore, fibres that treat the water chemically, for example in the form of ion exchange, may be provided. Thus, the drainage layer participates in the treatment process of the water, which can consequently be configured more effectively. 
         [0036]    In an embodiment, at least one of the filter bodies is at least partly covered by a stabilisation covering. 
         [0037]    This stabilisation covering may in particular be a on-woven or woven fabric covering, with which at least the filter faces are covered. The stabilisation covering is chosen such that it has high tensile strength. If the filter body is loaded by bending, the stabilisation covering absorbs the tensile forces that arise and reduces the risk of fracture of the filter body. 
         [0038]    In an embodiment, the planar filter bodies comprise at least one material from the group comprising activated carbon and ion exchange material. 
         [0039]    Such a planar filter body therefore comprises activated carbon or ion exchange material or a mixture thereof, or consists of activated carbon or ion-exchange material or a mixture thereof. Activated carbon has a very high active surface, on which undesired constituents of the water to be filtered can be adsorbed. Water softening can be performed with the aid of the ion-exchange material, for example. Both materials are amenable to sintering and thus to being crafted into filter bodies. 
         [0040]    In an embodiment, at least one of the filter bodies has a permeability that varies within the filter body. 
         [0041]    In a variant, the permeability varies along a first longitudinal axis of the filter body. A change in the permeability brings about a change in the time the water to be treated requires to pass through the filter body. The required time is a measure of the level of treatment of the water. Provided that an identical pressure acts on the filter body, the level of treatment is higher the longer the water needs to flow through the filter body. This embodiment is particularly suitable for arrangement in a container for treating water, which container has a second longitudinal axis, the first and second longitulongitudinal axes extending essentially in parallel to each other. In the case of gravity-driven containers, the planar filter body is arranged essentially vertically in its intended orientation, and the water to be treated flows through the filter body in an essentially horizontal direction. The containers of filter systems common in the trade typically extend further in the axial direction, that is to say, along the above-defined second longitudinal axis, than in the radial direction. If the second longitudinal axis of the container is aligned parallel to the effective direction of gravity, the hydrostatic pressure changes along the second longitudinal axis. If the first and second longitudinal axes extend in parallel to each other, the hydrostatic pressure changes in a corresponding way along the first longitudinal axis of the filter body. Consequently, different flow times through the filter body will be given rise to. By means of an appropriately adjusted permeability gradient along the first longitudinal axis, the flow time can be kept constant over the entire filter body. The permeability may be adjusted, for example, via the density of the filter body. 
         [0042]    In an embodiment of the filter unit, the layer thickness of at least one of the filter bodies changes along a first longitudinal axis. 
         [0043]    As already explained, in the case of gravity-driven containers, the hydrostatic pressure increases with the height of the water column that stands above the bottom wall of the container. If the planar filter body is installed vertically, the hydrostatic pressure changes along the first longitudinal axis of the filter body, so that different flow times would occur. As described above, the volume flow {dot over (V)} through the filter unit decreases with increasing layer thickness ρ of the filter body. By means of the varying layer thickness, the changing hydrostatic pressure can be taken into account. For example, the layer thickness may increase with increasing hydrostatic pressure. Alternatively, a layer thickness decreasing with hydrostatic pressure may also be provided. This can be of use if one wishes to empty the containers as far as possible after ending the treatment operation. 
         [0044]    In an embodiment, at least one of the filter bodies is profiled. It may, for example, be provided with spherical protrusions or recesses. In this way, the filter surface is enlarged, such that an increased filtration volume flow can be achieved and the time for treating the water can be reduced. 
         [0045]    In a variant, the filter body is profiled in a wave-shaped or saw tooth-shaped manner. 
         [0046]    According to another aspect, the container according to the invention for treating water comprises at least one filter unit according to the invention. 
         [0047]    The container may further comprise the following: a wall which delimits a container interior space, wherein the at least one filter unit for filtering the water is arranged in the container interior space and the container interior space is subdivided into a supply section and a discharge section; supply means for supplying the water to the supply section of the container interior space; and an outlet arranged at least partly in the wall of the container for carrying off the water out of the discharge section of the container interior space. 
         [0048]    The outlet is located in the intermediate space between the filter bodies, so that atmospheric pressure prevails here and a pressure gradient towards the intermediate space is generated. Consequently, the water flows in the direction of the intermediate space. In this configuration, the filter area is again increased, in that a unit volume of the water to be treated can now flow through two or more filter bodies without the flow resistance increasing, which in turn further reduces the time required for the treatment. The intermediate space can be an empty space which, for example, is produced by means of spacers, so that the two filter bodies are arranged at a defined distance to each other. This produces an effect, in particular during the production, since the two filter bodies do not come into contact with each other during sintering and are not adhered to each other. 
         [0049]    In an embodiment of the container, the supply section is filled with granulate. 
         [0050]    This granulate may likewise consist of activated carbon or ion-exchange material or of another material suitable for water treatment, so that the water to be filtered is already subjected to a purification treatment in the supply section. The degree of treatment is thus increased. Arranging the granulate in the supply section also has the effect that the granulate cannot be discharged out of the container via the outlet, since it is held back by the filter unit. The granulate may be constituted such that it does not float on the water to be filtered. 
         [0051]    In an embodiment of the container, the filter unit covers the outlet. 
         [0052]    In particular if a cover layer for sealing off an end face of the filter body is provided, it is not necessary for any covering to be provided for the drainage section, since this is formed by the cover layer. 
         [0053]    in an embodiment, recesses into which at least one of the filter bodies can be inserted are provided in the wall. 
         [0054]    These recesses have a guiding and positioning function, so that they facilitate the insertion of the filter bodies into the container. Irrespective of the size and shape of the container, they can have the same dimensions, so that the filter bodies need be produced in only one size but are nevertheless insertable into different containers. For example, given an appropriate configuration of the recesses, a container extending conically can be fitted with a filter body that is not provided with a conical shape corresponding to that of the container. Thus, the flexibility of manufacturing of the containers according to the invention is increased. 
         [0055]    In an embodiment of the container, a sealing layer is provided between the wall and at least one of the filter bodies. 
         [0056]    This layer can on the one hand serve to attach the filter body to the container and on the other hand prevents the water to be treated from passing through between the wall and the filter body. This part would then not be treated. Consequently, the sealing layer has a sealing function and ensures the treatment of the whole of the water with which the container is charged. 
         [0057]    In an embodiment, the outlet further comprises a channel extending through the container interior space, to which the at least one filter unit is attached, which channel has openings for carrying off the filtered water. 
         [0058]    In this embodiment, the filter unit and the channel can be prefabricated and inserted into the container as a structural unit, which reduces the manufacturing and assembly effort. 
         [0059]    An embodiment comprises a supporting unit, attachable to the channel and communicating with the openings for arranging the at least one filter unit in the container interior space. 
         [0060]    The supporting unit simplifies the arrangement of the filter unit in the container interior space, so that manufacturing and assembly are simplified. Furthermore, the supporting unit and the channel can be produced in one piece, for example by means of an injection-moulding process. 
         [0061]    In an embodiment, the container is configured as a cartridge. 
         [0062]    The cartridge represents an embodiment of the container that comprises a holding means and sealing means. The cartridge can be inserted into a cup in which the filtered water is collected. The cup can have an outlet, with which the filtered water can be transferred conveniently and without pouring into, for example, a drinking vessel. The holding means permit the simple replacement of the cartridge, for example when the filter unit is exhausted. The sealing means prevents unfiltered water from reaching the cup. 
         [0063]    In an embodiment, the filter bodies have a first longitudinal axis and the container has a second longitudinal axis, the first longitudinal axes and the second longitudinal axis extending essentially in parallel to each other. 
         [0064]    In the case of gravity-driven containers, the planar filter body is arranged essentially vertically in their intended orientation, and the water to be treated flows through the filter body in an essentially horizontal direction. The containers of containers common in the trade typically extend further in the axial direction, that is to say, along the second longitudinal axis defined above, than in the radial direction. This arrangement of the planar filter body in the container has the effect that the water to be treated can be presented with a larger filter area, which leads to an increased filtration volume flow. The filter area is the area of the filter body through which the water flows. Thus, this arrangement of the filter body in the container ensures better utilisation of the installation volume present in the container and a reduction in the time required to treat the water. 
         [0065]    “Essentially parallel to each other” is to be understood in this connection to mean that one aims from a manufacturing point of view to produce an appropriate alignment of the filter body with respect to the longitudinal axis of the containers, wherein a certain deviation is put up with. However, in another embodiment of the container, the first and the second longitudinal axis can deviate considerably from an orientation parallel to each other, wherein the water to be treated nevertheless flows through the filter body in an essentially horizontal direction and the container interior space is subdivided into a supply section and a discharge section by the filter unit. 
         [0066]    In an embodiment, the filter bodies have a first longitudinal axis, and the container has a second longitudinal axis, wherein the first longitudinal axes extend essentially at right angles to the second longitudinal axis. 
         [0067]    In the intended orientation of the gravity-driven container, an essentially horizontal orientation of the filter bodies thus results. In this embodiment, several filter units can be arranged one above the other, so that the whole of the height of the container interior space can be utilized, so that the available installation volume is utilized effectively and a large filter area is made available. 
         [0068]    In an alternative embodiment of the container, the filter bodies have a first longitudinal axis and the container has a second longitudinal axis, wherein the first longitudinal axes and the second longitudinal axis enclose an angle between 0° and 90°. 
         [0069]    Through the choice of angle α, the filter area can be enlarged, which leads to an increase in the volume flow through the filter unit. Consequently, the time needed to treat a unit volume decreases. 
         [0070]    A further aspect of the present invention concerns the use of a filter unit according to the invention for treating water. 
         [0071]    Furthermore, in accordance with a separate aspect, a container for treating water is disclosed below, comprising: a wall which delimits a container interior space, a filter unit for filtering the water, arranged in the container interior space, which subdivides the container interior space into a supply section and a discharge section; supply means for supplying the water to the supply section of the container interior space; and an outlet arranged at least partly in the wall of the container for carrying off the water out of the discharge section of the container interior space, wherein the filter unit comprises a planar filter body. 
         [0072]    This container is characterised in that the supply section is filled with a granulate. It may optionally comprise a filter unit according to the invention. 
         [0073]    The filter body may be sintered. 
         [0074]    In the container, the planar filter body may comprise activated carbon or ion-exchange material or a mixture thereof or consist of activated carbon or ion-exchange material or a mixture thereof. 
         [0075]    The filter body of the container may have a first longitudinal axis, and the container may have a second longitudinal axis, wherein the first longitudinal axis and the second longitudinal axis extend essentially in parallel to each other. 
         [0076]    The planar filter body of the container may have a permeability, wherein the permeability varies within the filter body. 
         [0077]    The filter unit may have a layer thickness, wherein, the layer thickness changes along the first longitudinal axis. In particular, the filter body may be profiled. More particularly, the filter body may be profiled in a wave-shaped or saw tooth-shaped manner. 
         [0078]    The filter body may comprise two or more filter bodies spaced apart from one another, which delimit an intermediate space. In particular, a drainage layer may be arranged in the intermediate space. 
         [0079]    The intermediate space may have a thickness, wherein the layer thickness is two to three times as large as the thickness. 
         [0080]    The drainage layer may be a sheet structure, in particular a textile sheet structure made of a non-woven material, a knitted material or a woven material, wherein the sheet structure may comprise polyester or consist of polyester. In particular, the sheet structure may comprise chemically and/or physically active fibres. 
         [0081]    Recesses, into which the filter body can be inserted, may be provided in the wall of the container. 
         [0082]    Furthermore, a sealing layer may be applied between the wall and the filter body. 
         [0083]    Optionally, the filter body comprises a stabilisation covering, with which it is at least partly covered. 
         [0084]    In the container, a cover layer may be applied to seal off an end face of the filter body. In particular, the cover layer may cover and seal off the intermediate space. 
         [0085]    In an embodiment of the container, the filter unit covers the outlet. 
         [0086]    In an embodiment of the container, the filter unit comprises two or more filter bodies spaced apart from one another, and the filter bodies have a first longitudinal axis and the container has a second longitudinal axis, wherein the first longitudinal axis and the second longitudinal axis extend essentially at right angles to each other. 
         [0087]    In the container, the filter unit may comprise two or more filter bodies spaced apart from one another, and the filter bodies may have a first longitudinal axis and the container may have a second longitudinal axis and enclose an angle, wherein the angle is between 0 and 90°. 
         [0088]    Furthermore, the outlet may comprise a channel extending through the container interior space, to which channel the filter unit is attached and which is provided with openings for carrying off the filtered water. 
         [0089]    The container may be provided with a support unit, attachable to the channel and communicating with the openings, for arranging the filter unit in the container interior space. 
         [0090]    The container may also be configured as a cartridge. 
         [0091]    The outlet may be arranged in the side wall, and the filter body may be arranged upstream of the outlet, wherein the first and the second longitudinal axes extend essentially in parallel to each other. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0092]    The invention will be described in detail on the basis of embodiments with reference to the attached drawings, in which: 
           [0093]      FIG. 1  shows a plan view of a first exemplary embodiment of a container for treating water; 
           [0094]      FIG. 2  shows a side view of the first exemplary embodiment along the cross-sectional plane A-A defined in  FIG. 1 ; 
           [0095]      FIG. 3  shows a side view of the first exemplary embodiment along the cross-sectional plane B-B defined in Fig,  1 ; 
           [0096]      FIG. 4  shows a plan view of a second exemplary embodiment of a container for treating water; 
           [0097]      FIG. 5  shows a side view of the second exemplary embodiment of the container along a cross-sectional plane which corresponds to the cross-sectional plane A-A defined in  FIG. 1 ; 
           [0098]      FIG. 6  shows a plan view of a third exemplary embodiment of a container for treating water; 
           [0099]      FIG. 7  shows a side view of the third exemplary embodiment along the cross-sectional plane D-D defined in  FIG. 6 ; 
           [0100]      FIG. 8  shows a plan view of a fourth exemplary embodiment of a container for treating water; 
           [0101]      FIG. 9  shows a plan view of a fifth exemplary embodiment of a container for treating water; and 
           [0102]      FIG. 10  shows a plan view of a sixth exemplary embodiment of a container for treating water; 
           [0103]      FIG. 11  shows an isolated representation of a sandwich structure; 
           [0104]      FIG. 12  shows a plan view of a seventh exemplary embodiment of a container for treating water; 
           [0105]      FIG. 13  shows a side view of the seventh exemplary embodiment shown in  FIG. 12  along the cross-sectional plane E-E defined in  FIGS. 12 ; and 
           [0106]      FIG. 14  shows a side view of an eighth exemplary embodiment of a container for treating water. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0107]    The exemplary embodiment shown in  FIG. 1  shows a container  10   1  for treating water, which is provided with a wall  13  with a side wall  14  and a bottom wall  16  (cf.  FIG. 2 ) that delimit a container interior space  18 . The bottom wall  16  may however become superfluous through an appropriate choice of the wall  13 , for example when the wall  13  is configured conically or in the shape of a pyramid. In the illustrated example, the container  10   1  is provided with a circular cross-section but all other cross-sections are conceivable, for example polygonal or elliptical cross-sections. Arranged in the container interior space  18  is a filter unit  20 , which subdivides the container interior space  18  into a supply section  22  and a discharge section  24 . The supply section  22  is to be understood to mean the section of the container interior space  18  that is charged with untreated water, i.e. water which has not yet flowed through the filter unit  20 . In a corresponding way, the discharge section  24  is the section of the container interior space  18  in which there is treated water, which therefore has already passed through the filter unit  20 . 
         [0108]    Furthermore, the container  10   1  comprises supply means  26 , with the aid of which the untreated water is led into the supply section  22 . In the simplest case, this is a covering which covers the discharge section  24  whilst leaving the supply section  22  open (cf.  FIG. 3 ). The supply means  26  could also be configured as flexible tubes or funnels. 
         [0109]    Arranged in the discharge section  24  is an outlet  28 , via which the treated water is able to leave the container  10   1 . By definition, the outlet  28  should be part of the discharge section  24 . The filter unit  20 , which comprises a sintered, planar filter body  30 , is fixed to the side wall  14  and the bottom wall  16  (cf.  FIG. 3 ) and sealed off with respect to them by a sealing layer  32 . The sealing layer has both an adhesive and a sealing effect. 
         [0110]      FIG. 2  shows a side view along the cross-sectional plane A-A as defined in  FIG. 1 . The planar filter body  30  has a first longitudinal axis L 1 , and the container  10   1  has a second longitudinal axis L 2 . As is apparent from  FIG. 2 , the two longitudinal axes L 1  and L 2  coincide. in the case of gravity-driven containers  10 , the two longitudinal axes L 1 , L 2  extend along the effective direction of gravity g in the intended orientation, so that an essentially vertical arrangement of the planar filter body  30  results. 
         [0111]      FIG. 3  shows a side view along the cross-sectional plane B-B as defined in  FIG. 1 . The filter body  30  has a layer thickness ρ, which in the illustrated exemplary embodiment varies from the layer thickness ρ a  at the bottom wall  16  to the layer thickness ρ b  at the supply means  26 . In this case, the layer thickness ρ decreases from to ρ b . However, a change in the layer thickness ρ is not imperative, as is apparent from  FIG. 7 , for example. It is also apparent that the supply means  26  cover not only the discharge section  24  but also an end face  33  of the filter body  30 . 
         [0112]    For the treatment of water, the water to be treated is supplied to the container  10  in a suitable way. This can be done, for example, by means of a vessel which has an opening into which the container can be inserted (not illustrated). The supply means  26  ensure that the water to be treated can reach only the supply section  22  of the container interior space  18 . The supply section  22  is filled with the water to be treated, so that a positive pressure is built up here, which ensures that the water flows through the filter unit  20 , in this case the filter body  30 . In addition to the end faces  33 , the filter body  30  is provided with two filter areas  35   1  and  35   2 , via which the water to be treated enters the filter body  30  and leaves it again. In the illustrated example, the water to be treated enters into the filter body  30  via the filter area  35   1  and leaves it via the filter area  35   2 , so that the water to be treated flows through the filter body  30  essentially at right angles to the first longitudinal axis L 1  thereof, whereby it is treated. After flowing through the filter body  30 , the water passes into the discharge section  24  and then leaves the container  10  via the outlet  28 . As explained above, the supply means  26  also covers the end face  33  of the filter body  30 . This prevents that water to be treated is able to enter into the filter body  30  via the end face  33 . The water to be treated can consequently enter into the filter body  30  only via the filter area  35   1 , which leads to its having to cover a defined minimum distance through the filter body  30 , whereby a mini mal level of treatment is ensured. 
         [0113]      FIG. 4  shows a further exemplary embodiment of a container  10   2  for treating water, which largely corresponds to the exemplary embodiment of  FIGS. 1-3 . The side wall  14  has recesses  34 , into which the filter body  30  is inserted. In  FIG. 5 , the exemplary embodiment of the container  10   2  illustrated in  FIG. 4  is illustrated along the cross-sectional plane C-C defined in  FIG. 4 . The recesses  34  can be configured such that, for example, the filter body  30  illustrated in  FIGS. 1-3  can also be inserted into the container  10   2 , even though the latter has a conical shape. 
         [0114]      FIGS. 6 and 7  show a container  10   3  for treating water, which is provided with a wall  13  with a side wall  14  and a bottom wall  16  delimit a container interior space  18 . The bottom wall  16  can, however, become superfluous through an appropriate choice of the wall  13 , for example when the wall  13  is configured conically or in the shape of a pyramid. In the illustrated example, the container  10  is provided with a circular cross-section, but all other cross sections are conceivable, for example polygonal or elliptical cross-sections. Arranged in the container interior space  18  is a filter unit  20 , which subdivides the container interior space  18  into a supply section  22  and a discharge section  24 . The supply section  22  is to be understood to mean the section of the container interior space  18  which is charged with untreated water, i.e. water which has not yet flowed through the filter unit  20 . In a corresponding way, the discharge section  24  is the section of the container interior space  18  in which there is treated water, which therefore has already passed through the filter unit  20 . 
         [0115]    Furthermore, the container  10   3  comprises supply means  26 , with the aid of which the untreated water is led into the supply section  22 . This is a cover which covers the discharge section  24 , whilst leaving the supply section  22  open. This cover  24  will be explained further below. The supply means  26  could also be configured as flexible tubes or funnels. 
         [0116]    Arranged in the discharge section  24  is an outlet  28 , via which the treated water is able to leave the container  10   3 . By definition, the outlet  28  should be part of the discharge section  24 . The filter unit  20  is fixed to the side wall  14  and the bottom wall  16  and sealed off with respect to them by a sealing layer  32 . The sealing layer has both an adhesive and a sealing effect. 
         [0117]    For the treatment of water, the water to be treated is supplied to the container  10  in a suitable way. This can be done, for example, by means of a vessel which has an opening into which the container can be inserted (not illustrated). The supply means  26  ensure that the water to be treated can reach only the supply section  22  of the container interior space  18 . The supply section  22  is filled with the water to be treated, so that a positive pressure is built up here, which ensures that the water flows through the filter unit  20 . 
         [0118]    The exemplary embodiment of the container  10   3  illustrated in  FIGS. 6 and 7  is provided with two filter bodies  30   1  and  30   2  which are arranged spaced apart from each other in the container interior space  18  and delimit an intermediate space  48 . Arranged in this intermediate space  48  is a drainage layer  36 , wherein the intermediate space  48  may also however remain free. In the exemplary embodiment illustrated in  FIGS. 6 and 7 , the filter unit  20  is configured as a sandwich structure  38   1 , which is formed by the two filter bodies  30   1  and  30   2  and the drainage layer  36 . The sandwich structure  38   1  can be produced to a finished state before it is inserted into the container  10   3 . 
         [0119]    As is apparent from  FIG. 7 , the drainage layer  36  is arranged over the outlet  28 . Thus, in this case, the drainage layer  36 , together with the outlet  28 , forms the discharge section  24  of the container interior space  18  and fills the latter with the exception of the outlet  28 . The drainage layer  36  may be designed as a non-woven layer  40  but is only optional, can therefore also be omitted. Furthermore, the sandwich structure comprises a cover layer  46 , which covers both the two filter bodies  30   1  and  30   2  and also the free space  48  and/or the drainage and non-woven layer  36 ,  40  and seals them off. The cover layer  46  prevents that the water to be treated enters the filter body  30  via the end face and is able to reach the intermediate space untreated. In this case, the cover layer  46  forms the supply means  26 , so that the water to be treated can be introduced into the container interior space  18  without any further restrictions. Consequently, the water to be treated flows through each filter body  30   1 ,  30   2  essentially at right angles to the first longitudinal axis thereof, whereby it is treated. Since the water to be treated can enter into a filter body only via the filter area, it has to cover a defined minimum distance through the filter body  30 , whereby a minimal level of treatment is ensured. After flowing through the filter body  30 , the water passes into the discharge section  24  and then leaves the container  10  via the outlet  28 . 
         [0120]    Furthermore, the filter bodies  30   4  and  30   2  illustrated in  FIG. 7  have a permeability k which changes over the height h of the filter bodies  30   1  and  30   2 , the height h being measured starting from the bottom wall  16 . In the example illustrated, the penileability k increases with the height h. Thus, it is possible to take into account the height-dependent hydrostatic pressure, which decreases with height h, when a specific volume of the water to be filtered is present in the container  10   3 . 
         [0121]    The planar filter bodies  30   1  and  30   2  have a first longitudinal axis, and the container  10   3  has a second longitudinal axis. As is apparent from  FIG. 7 , the two longitudinal axes coincide. In the case of gravity-driven containers  10 , the two longitudinal axes extend along the effective direction of gravity g in the intended orientation, so that an essentially vertical arrangement of the planar filter bodies  30   1  and  30   2  results. 
         [0122]    Each of the filter bodies  30   1  and  30   2  has a layer thickness ρ. In a variant of the embodiment illustrated in  FIGS. 6 and 7 , the layer thickness ρ changes from a first layer thickness at the bottom wall  16  to a second layer thickness ρ at the supply means  26 . For instance, the layer thickness ρ decreases from the first to the second layer thickness. It can also be seen that the supply means  26  cover not only the discharge section  24  but also an end face  33  of the filter body  30 . 
         [0123]    The exemplary embodiment of the container  10   4  illustrated in  FIG. 8  is provided with two structured filter bodies  30   1 ′,  30   2 ′. In this case, they are structured in a saw tooth-shape but other structurings that lead to an increase in the filter area are conceivable. The drainage layer  36  matches the structure of the activated carbon bodies  30 ′ and together with the filter bodies  30   1 ′ and  30   2 ′, forms the sandwich structure  38   2 . Depending on the production method, the filter bodies  30 ′ are structured through completely, as illustrated, so that they are provided with the structure both on the side which faces the drainage layer  36  and also on the side which faces the supply or discharge section  22 ,  24 . Alternatively, the structure can be omitted on the side which faces the drainage layer  36 . 
         [0124]    A further exemplary embodiment of the container  10   5  is illustrated in  FIG. 9 , in which a total of three filter units  20   1 - 20   3  in the form of sandwich structures  38   3 - 38   3 ′″, each having a drainage layer  36 , is provided. In principle, the number of filter bodies  30  is not limited to a specific number. Furthermore, some or all of the drainage layers  36  can be omitted. An individual outlet  28  (not illustrated) is provided under each drainage layer  36 . 
         [0125]    In the exemplary embodiment illustrated in  FIG. 10 , the container  10   7  is provided with a quadrangular cross-section and three filter units  20   1 - 20   3  configured as sandwich structures  38   4 ′- 38   4 ′″, arranged one above the other, which largely correspond to that  38   1  which is shown in  FIGS. 6 and 7 . However, the container may also be provided with any other desired cross-section and be provided with a different number of sandwich structures  38   4 . In this example, the first longitudinal axes L 1a  and L 1b  of the filter bodies  30  do not coincide with the second longitudinal axis L 2  of the container, but rather are at right angles to one another, so that given an intended alignment of a gravity-driven container  10   7 , a horizontal orientation of the filter bodies  30  and of the drainage layers  36  and/or the sandwich structures  38   4  results. Departures from the alignment, described here by way of example, of the first and second longitudinal axes L 1  and L 2  are likewise conceivable (cf.  FIGS. 14 and 15 ). As in the other exemplary embodiments having the sandwich structures  38 , the outlet  28  adjoins the drainage layer  36 . Since the sandwich structures  38  extend essentially horizontally and thus are essentially at right angles to the side wall  14 , the outlet  28  extends within the side wall  14 . 
         [0126]    If water to be treated is now put into the container  10   6 , then hydrostatic pressure acts on both filter bodies  30   1  and  30   2  of the sandwich structures  38   4  in the case of purely gravity-driven systems, an excess pressure in the case of pressureoperated systems. Since, as already described further above, atmospheric pressure prevails in the intermediate space between the two filter bodies  30   1  and  30   2 , the water to be treated flows through the two filter bodies  30   1  and  30   2  to the drainage layer  36  due to the pressure difference, as indicated by the arrows, wherein it flows through the activated carbon body  30   2  in a direction counter to the effective direction of gravity. 
         [0127]    In  FIG. 11 , a sandwich structure  38  is shown in isolation. As already explained, it comprises the two filter bodies  30   1  and  30   2 , which are arranged spaced apart from each other and form an intermediate space  48 . In the example illustrated, the drainage layer  36 , implemented as a non-woven layer  40 , is arranged in the intermediate space  48 . in addition, the filter bodies  30   1  and  30   2  are covered by a stabilisation covering  42 , which can be implemented as a non-woven covering  44 . 
         [0128]    In  FIGS. 12 and 13 , a further exemplary embodiment of a container  10   7  for treating water is illustrated. This comprises a sandwich structure  38   5 , which is connected only to the bottom wall  16 , is sealed to the latter by means of the sealing layer  32  and is sealed off with respect to said bottom wall. The sandwich structure  38   5  has no contact with the side wall  14  and covers the outlet  28 . Furthermore, the supply section  22  is filled with a granulate  62 , which is retained by the filter unit, so that it cannot leave the container  10   7  via the outlet  28 . 
         [0129]    In  FIG. 14 , the container  10   8  is configured as a cartridge  12 . The essential features of a cartridge are holding means  56 , with which the cartridge  12  can be plugged into a cup, not illustrated. The cup is used to collect the filtered water. Furthermore, the container is provided with sealing means  58 , which prevent unfiltered water from reaching the cup. 
         [0130]    In the example illustrated in  FIG. 14 , the outlet  28  also comprises a channel  50  having a longitudinal axis L 2 , to which channel three sandwich structures  38   6 ′- 38   6 ′″ having longitudinal axes L 1a  and L 1b  and spaced apart from one another in relation to the longitudinal axis L 2  are attached. The longitudinal axes L 1a  and L 1b  are essentially at right angles to the longitudinal axis L 2 , in the area of the drainage layer of the sandwich structures  38   6 , the channel  50  is provided with openings  52 , through which the filtered water is able to leave the container. Furthermore, the sandwich structures are sealed off with respect to the channel  50  by means of the sealing layers  32 , so that no unfiltered water could run along the channel  50  and pass through the openings  52 . Furthermore, the sealing layers  32  can have a fixing function, so that they fix the sandwich structures  38   6  to the channel  50 . Furthermore, at their end facing away from the channel  50 , the sandwich structures are provided with a cover layer  46  which prevents water from passing directly into the drainage layer and there fore through the containers unfiltered. Moreover, at its end facing away from the bottom wall  16 , the channel  50  is closed by a closure element  60 , so that the water to be filtered cannot flow through the container unfiltered. In this case, the closure element  60  simultaneously also forms the supply means  26 , since the effect of the closure element  60  is that the water is supplied only to the supply section of the container. 
         [0131]    The first and the second longitudinal axis L 1  and L 2  enclose an angle α, which, in the example illustrated, is 90°. However, it is also possible to vary the angle α between 0 and 90°. 
         [0132]    The flow through the sandwich structures  38   6  takes place in an essentially analogous way to that which was described for the exemplary embodiment described in  FIG. 10 . 
       LIST OF REFERENCE SYMBOLS 
       [0000]    
       
           10  Container 
           12  Cartridge 
           13  Wall 
           14  Side wall 
           16  Bottom wall 
           18  Container interior space 
           20  Filter unit 
           22  Supply section 
           24  Discharge section 
           26  Supply means 
           28  Outlet 
           30  Filter body 
           32  Sealing layer 
           33  End face 
           34  Recess 
           35  Filter area 
           36  Drainage layer 
           38  Sandwich structure 
           40  Sheet structure 
           42  Stabilisation covering 
           44  Non-woven covering 
           46  Cover layer 
           48  Intermediate space 
           50  Channel 
           52  Opening 
           56  Holding means 
           58  Sealing means 
           60  Closure element 
           62  Granulate 
         D Thickness of the intermediate layer 
         g Force of gravity 
         L 1  First longitudinal axis 
         L 2  Second longitudinal axis 
         α Angle enclosed by L 1  and L 2    
         ρ Layer thickness of the filter body