Abstract:
A cartridge containing a single serving of a particulate substance extractable by means of water for preparing a beverage, preferably an espresso coffee beverage is disclosed. Between the bottom of the cartridge and the particulate substance as well as between the particulate substance and the cover of the cartridge, in each case a fluid director member is provided, having a plurality of small openings. The one close to the cover serves as a water distribution member for distributing the water, fed into the cartridge through a central opening pierced therein, evenly over the particulate substance, and the one close to the bottom serves as a beverage collection member to lead the beverage to a central opening pierced into the bottom of the cartridge. Both director members are provided with a recess directed towards the interior of the cartridge, allowing the penetration of a piercing member without damage to the director members.

Description:
BACKGROUND OF THE INVENTION 
   The present invention refers to a cartridge adapted to contain a single serving of a particulate substance, extractable by means of water for preparing a beverage, preferably an espresso coffee beverage, comprising an essentially cup- or bucket-shaped main body portion having a bottom portion and an open end opposite to the bottom portion, and a cover member adapted to be sealingly attached to the open end of the main body portion. 
   Such cartridges are well known in the art in a variety of different embodiments, whereby particularly cartridges containing a single serving of coffee powder for preparing an espresso coffee are in widespread use. One of the fundamental advantages of such cartridges may be seen in the fact that they are gas tight, thus keeping the ground coffee contained therein fresh over an extended period of time. For brewing the coffee powder received in the cartridge, predominantly semi-automatic espresso coffee machines are in use whereby the cartridge is inserted into a cartridge holder of the machine, with its cover facing downwards. Then, the cartridge holder is inserted manually into the coffee machine. The coffee machine is provided, in the region of the area where the cartridge holder is to be inserted into the machine, with a so-called brewing spike, i.e. a hollow piercing member comprising radial outlet openings for feeding the brewing water into the interior of the cartridge, once the bottom of the cartridge has been pierced upon insertion of the cartridge holder into the coffee machine. The bottom of the cartridge holder itself is provided with a plurality of projections located on a collecting tray. These projections penetrate the cover of the cartridge and provide a plurality of openings in the cover as soon as pressurized brewing water is fed into the cartridge and the cover thereof is pressed against the projections due to the hydraulic overpressure in the interior of the cartridge. During the subsequent brewing operation, the brewing water is fed into the interior of the cartridge through the brewing spike, with the result that it flows under pressure through the coffee powder in the cartridge, finally leaving the cartridge as coffee beverage through the openings in the cover. The freshly brewed coffee is collected in the collecting tray and flows through a beverage outlet out of the machine. A coffee machine comprising such a setup for the extraction of the coffee powder contained in a cartridge is disclosed, for instance, in the document EP 0,512,470. 
   The disadvantage of a brewing spike having radially extending outlet openings may be seen in the fact that the cross sectional area of the brewing spike relevant for the outlet of the brewing water relatively quickly clogs under the influence of contaminations. As a reason therefore, for instance fat contained in the coffee powder, coffee powder particles, lime in the brewing water etc. can be named. However, the brewing spike being gradually more and more contaminated, the quality of the brewed coffee beverage gradually decreases. As far as the hydrodynamic standpoint is concerned, the problem in using brewing spikes of the kind referred to herein before is the fact that so-called dead volumes exist in the interior of the cartridge, with the result that portions of the coffee powder are extracted not at all or only to a minor extent. 
   PRIOR ART 
   The document EP 0,521,188 discloses an apparatus for extracting coffee powder contained in a cartridge. Besides a brewing spike for feeding brewing water into the interior of the cartridge, a water distribution grid is provided in a preferred embodiment, having elements projecting from its bottom to perforate the top portion of the cartridge. The brewing water is distributed over the top of the cartridge by the water distribution grid and can flow into the cartridge through the gap between the projecting elements and the cover of the cartridge. 
   Moreover, the document EP 0,512,468 discloses a cartridge referred to herein and adapted to contain a single serving of coffee powder. The cartridge is made of a composite material, does not comprise any filter and no portions with reduced strength, whereby the bottom and the cover of the cartridge are adapted to break up under the influence of the pressure exerted by the extraction fluid at the beginning of the extraction process. 
   A fundamental disadvantage of the known cartridges containing a single serving of an extractable particulate substance, e.g. coffee powder, may be seen in the fact that a lot of effort has to be taken at the end of the coffee machine to ensure that the coffee powder contained in the cartridge is as fully extracted as possible, i.e. to ensure that the brewing water flows uniformly through the entirety of the coffee powder. Moreover, with cartridges that open up only under the influence of the pressure exerted by the extraction fluid, at the beginning of the extraction, the danger exists that they do not open at the desired locations and are not perforated where desired, respectively, with the result that the coffee powder is insufficiently extracted again. Finally, as further disadvantage lies in the fact that the perforations often are too big; this is far from desirable because the extracting fluid is not opposed to a sufficiently high flow resistance, whereby there is also the danger that coffee powder can leave the cartridge, thereby contaminating the coffee machine unnecessarily. 
   The document EP 1,101,430 discloses a beverage-filter-cartridge system, comprising a staggered single serving cartridge. The cartridge comprises several steps for supporting a filter element and a porous diaphragm, respectively. The beverage powder is received between the filter element and the diaphragm. Both between the cover of the cartridge and the filter element and between the bottom of the cartridge and the diaphragm, a cavity is provided for laterally inserting an inlet tube and an outlet tube, respectively. 
   Finally, U.S. Pat. No. 2,778,739 discloses a package for beverage infusion material. The package comprises a bowl-shaped housing, containing a metallic insert. The top of the housing is provided with a welded-on cover. The afore mentioned insert comprises a circular outer recess and an inner, central recess. The central recess is deeper than the outer recess and is adapted to receive a piercing member by means of which the bottom of the package is perforated. The piercing member simultaneously serves for feeding brewing water. The insert comprises a plurality of openings through which the brewing water can flow into the interior of the package. For perforating the package cover, further perforating means are provided. 
   OBJECTS OF THE INVENTION 
   It is an object of the invention to provide a cartridge adapted to contain a single serving of a particulate substance, extractable by means of water for preparing a beverage, preferably an espresso coffee beverage, in which the brewing water flows through the extractable substance contained therein as uniformly as possible to thereby extract the substance as fully as possible. 
   It is a further object of the invention to provide a cartridge adapted to contain a single serving of a particulate substance, extractable by means of water for preparing a beverage, preferably an espresso coffee beverage, in which the associated coffee machine can be kept as simple as possible, removing the need to provide the machine with means for distributing and/or collection the brewing water and the beverage, respectively, with regard to the cartridge. 
   It is a still further object of the invention to provide a cartridge adapted to contain a single serving of a particulate substance, extractable by means of water for preparing a beverage, preferably an espresso coffee beverage, in which the brewing water can flow through the cartridge either from cover to bottom or vice versa, without the need to provide substantial structural modifications to the cartridge. 
   SUMMARY OF THE INVENTION 
   To meet these and other objects, the invention provides a cartridge adapted to contain a single serving of a particulate substance, extractable by means of water for preparing a beverage, comprising an essentially cup- or bucket-shaped main body portion having a bottom portion and an open end opposite to said bottom portion, a cover member adapted to be sealingly attached to the open end of the main body portion, and at least one fluid director member having essentially disc-shaped configuration with a central longitudinal axis and a dimension essentially corresponding to the interior cross sectional dimension of the main body portion, the fluid director member adapted to be received in the interior of the main body portion. 
   Each fluid director member is provided with a plurality of openings and a plurality of embossings, each of the embossings having a raised portion, whereby a plurality of communicating fluid channels is created between the raised portions of the embossings. 
   By providing at least one fluid director member of the kind explained herein above, for example at the inlet side of the cartridge above the particulate substance, a uniform distribution of the water fed into the cartridge for extracting the particulate substance can be ensured, independent of the number and the size of the inlet perforations. 
   Preferably, two fluid director members are provided, a first one upstream the particulate substance and serving as a fluid distribution member and a second one downstream the particulate substance and serving as a fluid collector member. Besides a uniform distribution of the brewing water, as explained above, such an embodiment has the advantage that the particulate substance is enclosed between the two fluid director members, thereby preventing any particles of that substance to escape through the inlet and/or outlet perforation(s), even if these should be relatively big. 
   Particularly, in a preferred embodiment, the cartridge comprises a first fluid director member having a plurality of openings and a plurality of embossings, each of the embossings having a raised portion, whereby a plurality of communicating fluid channels is created between the raised portions of the embossings, and whereby the first fluid director member is located in the interior of the cartridge between the particulate substance and the cover member, thereby constituting a distribution member for the water flowing through said particulate substance. The raised portions of the embossings rest on the cover member such that the raised portions of the embossings and the cover member delimit the fluid channels. 
   In that preferred embodiment, the cartridge further comprises a second fluid director member also having a plurality of openings and a plurality of embossings, each of the embossings having a raised portion, whereby a plurality of communicating fluid channels is created between the raised portions of the embossings, and whereby the second fluid director member is located in the interior of the cartridge between the particulate substance and the bottom of the main body portion, thereby constituting a collection member for the water flowing through said particulate substance. The raised portions of the embossings of the second fluid director member rest on the bottom portion such that the raised portions of the embossings and the bottom portion delimit the fluid channels. 
   In both the first and the second fluid director members, openings are located in the fluid channels created between the raised portions of the embossings, and both the first and second fluid director members comprise at least one recess projecting in a direction opposite to the direction of the raised portions of the embossings for providing space to receive a piercing member penetrating the cover member and/or the bottom portion without the first and/or second fluid director members being damaged by the piercing member. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the following, embodiments of the cartridge according to the invention will be further described, with reference to the accompanying drawings, in which: 
       FIG. 1  shows an exploded view of a still empty cartridge; 
       FIG. 2  shows a central longitudinal sectional view of a first embodiment of the cartridge according to the invention; 
       FIG. 3  shows a central longitudinal sectional view of a second embodiment of the cartridge according to the invention; 
       FIG. 4  shows a central longitudinal sectional view of a third embodiment of the cartridge according to the invention; 
       FIG. 5  shows a central longitudinal sectional view of a forth embodiment of the cartridge according to the invention; 
       FIG. 6  shows a central longitudinal sectional view of a fifth embodiment of the cartridge according to the invention, and: 
       FIG. 7  shows a partial cross sectional view of the fifth embodiment of the cartridge along the lines VII-VII in  FIG. 6 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The general design of a cartridge adapted to receive a single serving of a particulate substance, extractable by means of water for preparing a beverage, is shown in  FIG. 1  in an exploded view and shall be further explained herein below. Even if such cartridges basically are adapted to contain various different particulate substances extractable by means of water in order to prepare a beverage, in the following, embodiments of the cartridge are further described which are particularly suitable to contain coffee powder for preparing normal coffee or so-called espresso coffee. 
   As viewed from bottom to top of  FIG. 1 , the cartridge comprises a bucket- or cup-shaped main housing portion  1 , a lower fluid collection member  2 , an upper fluid distribution member  3  and a cover  4 . The coffee powder, to be received in the main housing portion  1  between the fluid collection member  2  and the fluid distribution member  3 , is omitted from this illustration for clarity&#39;s sake. Both, the main housing portion  1  and the cover  4  consist of a gas-tight multi-layer composite foil material. The fluid collection member  2  and the fluid distribution member  3  both are generally disc-shaped and are manufactured preferably by deep drawing. 
   The main portion  1  of the cartridge, slightly conical by having an increasing diameter from bottom to top, is provided with a peripheral portion  5  with greater diameter, thus having an annular shoulder  5   a  at the inner side of the wall of the main portion  1  of the cartridge. This shoulder  5   a  serves as a support for the upper distribution member  3 , i.e. the upper distribution member  3 , once inserted into the main portion  1  of the cartridge, rests on the shoulder  5   a . The main portion  1  of the cartridge comprises a peripheral rim  6 , and the cover  4  is fixed to that peripheral rim  6  e.g. by gluing or welding. 
   The collection member  2  is provided with a plurality of embossings having the shape of annular segments; these embossings show as raised portions  9  protruding from the bottom surface of the lower collection member  2 . Once the collection member  2  having been inserted into the main portion  1  of the cartridge, the raised portions  9  rest on the flat bottom surface of the main portion  1 , with the result that a plurality of fluid channels  17  are created, running from the central longitudinal axis of the collection member  2  radially outwards and concentrically around the central longitudinal axis of the collection member  2 . Beside the raised portions  9 , i.e. in the region of the thus created fluid channels  17 , the collection member  2  is provided with a plurality of openings  8 . The center of the collection member  2  comprises a conically shaped recess  10 , directed towards the interior of the cartridge, i.e. in opposite direction as compared to the raised portions  9 . The generally flat central portion of the collection member  2  merges in a radius  11  into a cylindrical edge portion  12  directed upward, as seen in  FIG. 1 . By this design, a tilt of the collection member  2  is avoided when it is inserted into the main portion  1  of the cartridge. 
   As far as the design is concerned, the upper distribution member  3  is essentially a mirror image of the lower collection member  2 . Again, the distribution member  3  comprises a plurality of embossings having the shape of annular segments; these embossings show as raised portions  13  protruding from the top surface of the upper distribution member  3 . By means of these raised portions  13 , a plurality of fluid channels  18  are created at the top surface of the upper distribution member  3 , these fluid channels  18  running from the central longitudinal axis of the distribution member  3  radially outwards and concentrically around the central longitudinal axis of the distribution member  3 . Beside the raised portions  18 , i.e. in the region of the thus created fluid channels  18 , the distribution member  3  is provided with a plurality of openings  14 . The center of the distribution member  3  comprises a conically shaped recess  15 , directed towards the interior of the cartridge, i.e. in opposite direction as compared to the raised portions  13 . Along the periphery of the upper distribution member  3 , a first flat edge portion  19  is provided. The first flat edge portion  19  is raised with regard to the fluid channels  18 , and its top surface essentially flushes with the topmost portions of the raised portions  13 . An essentially cylindrical second edge portion  16  surrounds the first edge portion  19  and extends downwards, as seen in  FIG. 1 , i.e. in the same direction as the recess  15  provided in the center of the upper distribution member  3  and in opposite direction as compared to the raised portions  13 . 
   Upon insertion of the upper distribution member  3  into the main portion  1  of the cartridge, the distribution member  3  rests with the lower edge of the second edge portion  16  on the shoulder  5   a  of the enlarged peripheral portion  5  of the main portion  1  of the cartridge. 
   When hot brewing water is fed under pressure into the cartridge  1  for preparing e.g. a coffee beverage, as will be explained in more detail herein after, the upper distribution member  3  serves both as a filter and as a distributing means for the brewing water, while the lower collection member  2  similarly serves as a filter and as a collecting means for the prepared coffee beverage. 
     FIG. 2  shows a longitudinal sectional view of an assembled cartridge, containing a single serving of coffee powder KP. As can be seen in this drawing, the coffee powder KP is enclosed between the lower collection member  2  and the upper distribution member  3 . Moreover, it can be clearly seen that fluid channels  17  are created by the raised portions  9  of the lower collection member  2  resting on the bottom of the main cup- or bucket-shaped main portion  1  of the cartridge. Similarly, fluid channels  18  are created by the raised portions  9  of the upper distribution member  3  resting on the bottom surface of the cover  4  of the main portion  1  of the cartridge. 
   For perforating the cartridge, an upper piercing member  21  and a lower piercing member  20  are provided, adapted to be pushed through the cover  4  and the bottom of the main portion  1  of the cartridge, respectively. Particularly, the piercing members  20 ,  21  are pushed through the cover  4  and the bottom of the main, portion  1  of the cartridge above and below, respectively, and the recesses  15  and  10  provided in the distribution member  3  and the collection member  2 , respectively, receive the piercing members  21 ,  20 . Thus, upon piercing the cover  4 , the upper distribution member  3  is not damaged by the piercing member  21 ; similarly, upon piercing the bottom of the main portion  1  of the cartridge, the lower collection member  2  is not damaged by the piercing member  20 , since the piercing members  20  and  21 , respectively, extend into the recesses  15  and  10 , respectively. 
   Preferably, the brewing water, required for brewing the coffee powder KP contained in the cartridge, is fed into the interior of the cartridge from the outside through the perforation provided by the piercing member  21 , as it is explained in more detail in the document EP 01 810 498, and the prepared coffee beverage leaves the cartridge through the perforation provided by the piercing member  20 . However, it is not compulsory at all that the brewing water be fed to a central inlet perforation and the coffee beverage leaves the cartridge through a central outlet perforation of the cartridge. However, important is that the brewed coffee beverage, by providing the collection member  2 , can flow as unobstuctedly as possible to the outlet opening or if appropriate, outlet openings. 
   In the present example, it will be assumed that the brewing water is led through the cartridge from top to bottom, as seen in  FIG. 2 . However, it is easily possible to have the brewing water flow through the cartridge in the opposite direction, i.e. from the bottom to the top, as seen and symbolized in  FIG. 2  by the double arrow  22 . 
   Under the influence of the fluid channels  18 , the brewing water fed into the cartridge is evenly distributed over the entire cross sectional area of the cartridge. Then, the brewing water flows through the openings  14  provided in the upper distribution member  3  and continuous its flow through the coffee powder KP contained in the cartridge. Having passed and thereby extracted the coffee powder, the brewing water, i.e. now being the brewed beverage, passes the openings  8  provided in the lower collection member  2  and flows to the bottom side of the collection member  2 . Finally, the coffee beverage flows through the fluid channels  17  located at the bottom of the main portion  1  of the cartridge and defined by the raised portions  9  of the collection member  2  to a central outlet opening, created by the piercing member  20 . There, it escapes the cartridge and continues its path along not shown means to a (not shown) beverage outlet. 
   By providing a cartridge with a distribution member  3  and a collection member  2 , designed as described herein above, it is ensured that the brewing water homogenously flows through the entirety of the coffee particles contained in the cartridge to achieve a uniform extraction of the entire coffee powder. In the case where the brewing water flows through the cartridge from bottom to top, the function of the distribution member  3  and the collection member  2  is interchanged, the lower member  2  now acting as a distribution member and the upper member  3  now acting as a collection member. In this context, the designations “distribution member  3 ” and “collection member  2 ” refer to the mode of operation with the brewing water flowing from top to bottom, but should not be understood as limiting in any way. 
   In any case, the raised portions  9 ,  13  are distributed over the area of the distribution member  3  and the collection member  2 , respectively, such that the distribution and collection members  3 ,  2  rest uniformly, over their entire surface area, on the bottom of the main portion  1  and the cover  4 , respectively. This is particularly advantageous in the case, as described herein above, if the brewing water is fed into the cartridge through a central piercing. By the aforementioned uniform support of the distribution and collection members  3 ,  2 , it is ensured that the cavities  13   a ,  17   a  constituting the fluid channels  18 ,  17  are kept open even if a substantial external pressure is exerted on the cartridge. If appropriate, the interior of the cartridge may comprise vertical separator walls (not shown), contributing to an even more uniform flow of the brewing water through the coffee powder and/or to the rigidity of the cartridge itself. 
   The diameter of the openings  8 ,  14  provided in the distribution member  2  and in the collection member  3  preferably is smaller than the statistical diameter of a single coffee powder particle used to prepare the beverage, and even more preferably smaller than x-σ, whereby x is the statistical mean value of the diameter of a particle and σ is the standard deviation. Thereby, it is ensured that, in practice, no particles can escape from or are flushed out of the interior of the cartridge, independent of the size of the piercing. 
     FIG. 3  shows a longitudinal sectional view of a second embodiment of a cartridge according to the invention that is not fully loaded with coffee powder KP. By the provision of an auxiliary frame member  25 , the lower distribution member  24  is kept in such a distance from the bottom  7  of the cartridge that the coffee powder fully occupies the space between the lower distribution member  24  and the upper collection member  26 . Thereby, it can be avoided that the coffee powder KP is contained in the cartridge in uneven distribution; such a situation would result in the fact that the brewing water would not be evenly distributed in the interior of the cartridge, further resulting in some sort of hydraulic short circuit. Thereby, the brewing water would not evenly extract the coffee powder. In this embodiment, the brewing water should be fed into the interior of the cartridge from the bottom  7  thereof, since the lower distribution member  24  cannot take high hydraulic pressure forces acting in the direction towards the bottom  7  of the cartridge. 
     FIG. 4  shows a longitudinal sectional view of a third embodiment of a cartridge according to the invention, again not fully loaded with coffee powder KP. By the provision of an auxiliary frame member  30  resting on the shoulder  5   a  and the cover  4 , the upper collection member  29  is kept in such a distance from the cover  4  of the cartridge that the coffee powder fully occupies the space between the upper distribution member  29  and the lower collection member  28 . In this embodiment, the brewing water is fed through the cover  4  into the interior of the cartridge. 
     FIG. 5  shows a longitudinal sectional view of a fourth embodiment of a cartridge according to the invention, similar to the third embodiment, that is again not fully loaded with coffee powder KP. Similarly, by the provision of an auxiliary frame member  32 , the upper collection member  31  is kept in such a distance from the cover  4  of the cartridge that the coffee powder fully occupies the space between the upper collection member  31  and the lower distribution member  28 . However, in this embodiment, the frame  32  is designed to be rigid by the provision of an annular inner portion  33  and a plurality of vertical struts (not shown in  FIG. 5 ). Thus, the brewing water can be fed into the cartridge from the bottom, as indicated by the solid arrow. It is understood that the frame  32 ,  33 , in operation, does not rest on the cover  4  of the cartridge, but on suitable elements provided on the coffee machine (not shown). It is further understood that the brewing water could be fed into the cartridge from the other side, i.e. through the cover  4 . 
     FIG. 6  shows a longitudinal sectional view of a fifth embodiment of a cartridge according to the invention, similar to the second embodiment, again not fully loaded with coffee powder KP. In this embodiment, the lower collection member  36  is supported on the bottom  7  of the cartridge by means of a pressure resistant rigid frame  35 . 
   Finally,  FIG. 7  shows a partial cross sectional view of the fifth embodiment of the cartridge taken along the line VII-VII in  FIG. 6 . In this view, the annular inner portion  33  and the vertical struts  37  of the frame  5  are clearly visible. 
   If the distribution member or the collection member is located in a certain distance from the bottom  7  and the cover  4  of the cartridge, respectively, there is no need to provide recesses  10  and  15 , respectively, in the collection and distribution members, respectively, for receiving the piercing member  20  or  21 , since the piercing member  20  or  21  can extend into the free space between bottom  7  and cover  4 , respectively, of the cartridge and distribution and collection member, respectively, without damaging the one or the other one of these members. 
   Instead of a central, conically shaped recess  10 ,  15 , for receiving the piercing member  20  or  21 , for instance an annular recess having a conical cross section could be provided. Such an annular recess would be useful in case of providing a plurality of piercing members distributed along a circular path. Further, instead of a conically shaped recess, for example a hemispherical recess or a recess in the shape of a rectangular parallelepiped could be provided. In order to facilitate the piercing of the cover or the bottom of the cartridge by means of the piercing member, the bottom or the cover of the cartridge could be provided with an area having reduced strength. However, such reduced strength area would have to be designed such that the layer of the multiplayer composite foil that is gas tight will not be impaired. All these afore mentioned embodiments are not specifically shown in the drawings. 
   With a cartridge designed according to the invention and as herein before described, a number of advantages can be realized:
         By the provision of a distribution member, the brewing water entering the interior of the cartridge is evenly distributed over the entire cross sectional area of the cartridge, resulting an an uniform extraction of the coffee powder. The same is true even if the cartridge is not fully loaded with coffee powder.   Escaping or flushing out of coffee powder particles is avoided to a great extent, resulting in a considerable reduction of the contamination of the coffee machine. Insofar, also the size of the piercing of the cartridge is of subaltern importance.   The size of the piercing is of no further importance regarding the flow velocity of the brewing water, because the brewing water hits a constant flow resistance, independent from the size of the piercing, but determined by the size of the openings in the fluid director members.   The coffee powder cartridges according to the embodiments shown in  FIGS. 2 ,  5  and  6  can be universally used because it does not matter in what direction the brewing water flows through the cartridge, be it from top to bottom or vice versa.   Only one single piercing has to be provided both at the side facing the distribution member and at the side facing the collection member.