Abstract:
A single serve brewing container is made entirely of compostable and biodegradable materials. Problems associated with filter clogging and occlusion are solved by providing a filter which has a vertical section between upper and lower horizontal sections.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    None 
       BACKGROUND OF THE INVENTION 
       [0002]    A. Field of the Invention 
         [0003]    The present invention relates to single serve brewing packages used with brewers to make coffee, tea and other beverages. More specifically, the present invention relates to a single-serve brewing package made entirely out of compostable and biodegradable materials and adapted to be used to brew beverages in a brewer. 
         [0004]    B. Description of the Prior Art 
         [0005]    Beverages have been brewed for centuries. A variety pf brewing machines have been used to make coffee, tea and other beverages. Within the past fifteen years, brewers designed to make a single serving of a beverage at one time have grown in popularity. Popular single-serve brewing machines today include machines manufactured by Keurig Green Mountain, Inc. of Waterbury, Vt. and machines sold by Kraft Foods under the Tassimo trademark. 
         [0006]    These machines are used in combination with cartridges which contain the dry ingredients necessary to brew a single cup of a beverage. Such cartridges are packages within different ingredients (e.g., different coffee blends) designed to yield beverages having different tastes. Thus, each member of a household (or each patron of an establishment) is able to select between various blends to brew a cup of a beverage according to taste. 
         [0007]    A number of environmental pitfalls have arisen as a result of the popularity of brewers which use such cartridges. The single-serve cartridges typically used with such brewers are generally not reusable because they are pierced by components of the brewer as part of the brewing process. Such cartridges are rarely, if ever, recycled. These cartridges are typically made of non-biodegradable and non-compostable plastics and the covers of such cartridges are often made of aluminum. Such cartridges are destined to last for decades, if not centuries, after they have been used. As such, landfills across America and throughout the world are literally filling up with the single serve cartridges used with such brewers. Since recycling of such packages has proven to be impractical and has not substantially reduced the amount of waste generated, there is a real need for a commercially viable single serve brewing package which is made entirely out of compostable and biodegradable materials. 
       SUMMARY OF THE INVENTION 
       [0008]    This disclosure describes single-serve brewing packages comprising a cup and a filter assembly, both of which are made out of a compostable and biodegradable material such as a crystalline polylactic acid. The cup has a closed bottom adapted to be pierced by a needle of a brewing machine to extract the brewed beverage, such as coffee, through the bottom of the cup. The cup also has an open top defined by a rim and a side wall extending between the open top and the rim. A filter assembly support ledge extends from the side wall into a first chamber defined by the cup. The side wall also includes reinforcement ribs. The filter assembly comprises a filter membrane and a filter frame for supporting the filter membrane. The filter frame comprises a ring having a central passage and adapted to nest, and be secured in place, between the bottom of the cup and the filter assembly support ledge of the cup. The filter frame also has filter membrane support ribs extending inwardly and upwardly from the ring and cooperating with the ring to support the filter membrane such that the filter membrane has a first horizontal position extending inwardly from the ring, a vertical portion extending upwardly from the first horizontal portion, and a second horizontal portion at the top of the vertical portion. No adhesives are required to secure the filter membrane to the filter frame. Both the filter membrane and the filter frame may be made of polylactic acid, a readily biodegradable and compostable plastic. These parts can be bonded together using heat. Alternatively, the filter frame and filter membrane may be integrally joined together during the molding process. Dried coffee, tea or ingredients for other beverages are placed in the cup and rest on top of the filter assembly. The single-serve brewing package disclosed also includes a lid for sealing the open top of the cup so that the single-serve brewing package may be used to store and transport the dry ingredients for the beverage to be brewed. The lid is also compostable and biodegradable. In one form, the lid comprises an upper layer made of biodegradable and compostable paper and a lower layer made of polylactic acid. Such a lid is particularly advantageous because labeling information may be printed on the paper layer and no adhesive is required to secure the lid to the cup. Instead, a heat seal is created between the polylactic acid forming the rim of the cup and the polylactic acid layer of the lid. Similarly, no adhesives are required to secure the filter membrane to the filter frame. Again, since both the filter membrane and the filter frame are made of polylactic acid, these parts can be bonded together using heat. 
         [0009]    When such a container is used to brew a beverage, the container is inserted into a pocket in a brewer. The bottom of the cup and lid are pierced separately by needles of the brewer. Hot water or some other liquid is then injected through the needle extending through the lid. The liquid mixes with the dry material in the container to brew the beverage. The filter assembly is adapted to permit the brewed beverage to pass through the filter membrane while retaining not only the coffee, tea or other beverage grounds above the filter, but also retaining above the filter any sludge produced as part of the brewing process. 
         [0010]    The ribs of the filter assembly and the manner in which they support the filter membrane are important features. In one embodiment of the invention, the filter membrane support ribs comprise a first rib extending across the central passage of the ring and a second rib extending across the central passage of the ring such that the central passage through the ring is divided into quadrants by the first and second ribs. Also, the design of the ribs allows the vertical portion of the filter membrane to extend up and into the material to be brewed. This vertical portion extends upwardly from the first horizontal portion to a height that allows at least 10 ounces of the beverage to pass through the filter membrane before the filter membrane becomes occluded with grounds and sludge. 
         [0011]    The single-serve brewing package described above can be used with other identical or similar single-serve brewing packages to form a single-serve brewing package system. This system allows the cups (and the filter assemblies located within the cups) to be stacked prior to being filled with material to be brewed and then sealed with the lid. This is achieved by providing a cup having a closed bottom that includes a base and a projection extending upwardly from the base and defining a second chamber open to the bottom of the cup and closed to the first chamber of the cup. Thus, when a second cup is nested with a first cup, the vertical portion and second horizontal portion of the filter membrane (and the associated portions of the support ribs) reside within the second chamber of a second cup. As mentioned above, the side wall of the cup has reinforcement ribs. These ribs are necessary to prevent the cup from losing its shape due to the pressures encountered when brewing the beverage. So that these reinforcement ribs do not interfere with stacking of the cups and so they, in fact, index the cups as they are stacked, these ribs have a triangular shape which helps to guide the cups together when forming the stack. 
         [0012]    These and other features and advantages of the present invention will become better understood from a reading of the following detailed description of the invention in conjunction with the following drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is a perspective view of a cup of a beverage package. 
           [0014]      FIG. 2  is a top plan view of a lid which may be used to cover the cup of  FIG. 1 . 
           [0015]      FIG. 3  is a side view of the cup of  FIG. 2 . 
           [0016]      FIG. 4  is a cross-sectional view of the cup of  FIG. 1 . 
           [0017]      FIG. 5  is a cross-sectional view of an alternative embodiment of a cup. 
           [0018]      FIG. 6  is a perspective view of a filter frame. 
           [0019]      FIG. 7  is a top view of the filter frame of  FIG. 6 . 
           [0020]      FIG. 8  is a side view of the filter frame of  FIG. 6 , 
           [0021]      FIG. 9  is a perspective view of the cup of  FIG. 1  with the filter frame of  FIG. 6  placed therein. 
           [0022]      FIG. 10  is a cross-sectional view of the cup and filter frame of  FIG. 9 . 
           [0023]      FIG. 11  is a top view of a filter membrane. 
           [0024]      FIG. 12  is a side view of the filter frame of  FIG. 6  with the filter membrane of  FIG. 11  attached. 
           [0025]      FIG. 13  is a top view of the filter frame of  FIG. 6  with the filter membrane of  FIG. 11  attached. 
       
    
    
     DETAILED DESCRIPTION 
       [0026]    A single-serve brewing package is shown in the drawings. The single-serve brewing package comprises a cup  10 , filter assembly  40  and a lid  80 . All of the components of the cup  10 , filter assembly  40  and lid  80  are made of a biodegradable and compostable material. As such, after use, the package and all of its components quickly degrade and do not adversely impact the environment. By way of example, the components of the cup  10  and filter assembly  40  are made of a crystalline polylactic acid (“PLA”) and the lid  80  comprises a paper layer over a layer of PLA. Since PLA components can easily be bonded together using heat, no separate adhesives are required. 
         [0027]    Two embodiments of the cup  10  are shown in the drawings. Each cup  10  defines a chamber  12 . Each cup  10  has a closed bottom  14 , an open top  16  defined by a rim  18 , and a side wall  20  extending between the rim  18  and closed bottom  14 . A filter assembly support ledge  22  extends inwardly from the support wall  20  into the chamber  12  and defines a filter ring support space  24  between the closed bottom  14  and the filter assembly support ledge  22 . The side wall  20  also includes a plurality of reinforcing ribs extending between the rim  18  and the filter assembly support ledge  22 . Each of the reinforcing ribs is generally in the shape of an isosceles triangle. The term “generally” is used because, geometrically, triangles are on a single plane and the ribs  26  and  28  extend in a curved fashion partially around the circumference of the cup  10 . The base of the triangle of reinforcing ribs  26  is at or near the rim  18 . The base of the triangle of reinforcing ribs  28  is at or near the filter assembly support ledge  22 . 
         [0028]    The primary differences between the two embodiments of the cup  10  shown in the drawings relate to the bottom  14  of the cup  10 . In one embodiment, shown in  FIG. 4 , the bottom  14  is flat. In the other embodiment, shown in  FIG. 5 , the bottom  14  comprises a flat base  30  and a projection  32  extending upwardly from the base  30 . The projection  32  has a generally frusto-conical side wall  34  which defines a second chamber  36 . The bottom  38  of the chamber  36  is open. The top  39  of chamber  36  is closed such that the closed bottom  14  of the cup  10  is defined by the base  30  in combination with the side wall  34  and closed top  39  of the projection  32 . 
         [0029]    The construction of filter assembly  40  is shown best in  FIGS. 6 through 13 . As shown in  FIGS. 11, 12 and 13 , the filter assembly  40  includes a filter membrane  42 . The membrane has pores  44  large enough to permit a brewed beverage to pass through the membrane  42 , but small enough to prevent coffee grounds (or the like) and brewing sludge from passing through the membrane  42 . In  FIGS. 12 and 14 , the size of the pores  44  are exaggerated. One skilled in the art should understand that the size of the pores  44  will depend on the nature of the material to be filtered and will typically be much smaller than as illustrated. The pores  44  will, for example, be about the same as the pores of a typical tea bag. 
         [0030]    The filter assembly  40  also includes a filter frame  46 . The filter frame  46  is best shown in  FIGS. 6 through 8, 12 and 13 . The filter frame  46  comprises a ring  48  surrounding a central passage  50 . The height and outside diameter of the ring  48  are adapted to the distance between the bottom  14  (base  30 ) and the filter assembly support ledge  22  of cup  10  so that the ring  48  can be nested between and secured in place by these structures of the cup  10 . The ring  48  may be provided with a top rim  52  which engages the filter assembly support ledge  22 . 
         [0031]    In addition to ring  48 , the filter frame  46  includes the filter membrane support ribs  54  and  56 . Each support rib  54  and  56  has five sections  61 - 65 . Sections  61  and  62  are joined to and extend generally diametrically and horizontally (inwardly) toward each other from the ring  48 . Section  63  extends vertically and upwardly from section  61  and section  64  extends vertically and upwardly from section  62 . Section  65  extends between the tops of sections  63  and  64  such that the support ribs  54  and  56  extend the full diameter of the ring  48 . Section  65  of rib  54  and section  65  of rib  56  cross at the center of the central passage  50 . As such, the ribs  54  and  56  cooperate to divide the central passage into quadrants  66 ,  67 ,  68  and  69  as best seen in  FIG. 7 . 
         [0032]    From the foregoing, the reader should appreciate that when the filter membrane  42  is coupled to and supported by the filter frame  46  as shown in  FIGS. 12 and 13 , the filter membrane  42  will have a first horizontal portion  70  extending inwardly from the ring  48  to the vertically extending sections  63  and  64  of the ribs  54  and  56 . The filter membrane  42  will also have a vertical portion  72  as the membrane  42  rises along the vertically extending sections  63  and  64 . Finally, the filter membrane will have a second horizontal portion  74  as the membrane  42  extends across the top of the vertical portion  72 , i.e., across section  65  of each of ribs  54  and  56 . While to make the parts and how they are assembled easier to view, the membrane  42  is not shown in  FIGS. 9 and 10 . However, the completed assembly will include the membrane  42  attached to the filter frame  46  as shown in  FIGS. 12 and 13 . 
         [0033]    The filter assembly  40  is adapted not to melt, warp or otherwise deform when the brewing package is used to brew hot beverages inside the package. This is because the filter assembly  40 , comprising the filter frame  46  and filter membrane  42 , is post heat treated to create resistance to heat and prevent warping during the brewing cycle. Alternatively, chemical additives may be added to the PLA or other biodegradable and compostable material used to make the filter assembly  40  more resistant to heat. When selecting any such chemical additive, it is important that the inclusion of the chemical additive not substantially interfere with the biodegradability and compostability of the filter assembly. Similar steps may be taken to improve the ability of the cup  10  to handle temperatures encountered when brewing. 
         [0034]    The above-described construction of the filter assembly  40  offers several other important advantages. First, vertical portion  72  serves to increase the total surface area of the filter membrane  42 . This allows for greater flow of a beverage through the filter membrane. Second, flow through the membrane  42  is multi-planar (e.g., horizontal and vertical) rather than essentially in a single plane, as is the case with flat filters. As such, the risk that the filter will become clogged or occluded with grounds or sludge during brewing is essentially eliminated. Third, even if the first horizontal portion  70  becomes occluded by grounds or sludge during brewing, the vertical portion  72  and second horizontal portion provide an overflow mechanism. 
         [0035]      FIGS. 2 and 3  show a lid  80  which may be employed to seal the open top  16  of the cup  10 . The lid  80  comprises a paper disk  82  laminated to a disk  84  made of PLA. The paper used and PLA are both compostable and biodegradable. The paper allows for printed information to be applied to the package  1 . The PLA  84  allows the lid  80  to be readily bonded to the cup  10  using heat. PLA has a relatively low melting temperature so sufficient heat applied to the rim  18  of cup  10  and/or the PLA layer  84  of the lid  80  will bond the lid  80  to the cup  10 . 
         [0036]    Packaging of beverage ingredients will now be described using coffee as an example. Packaging of ingredients for other beverages may be carried out in the same way. in one embodiment, a stack of cups  10  and a stack of filter assemblies  40  is procured. The cups  10  are easily stacked given the triangular shape and arrangement of the reinforcing ribs  26  and  28  which allow the cups  10  to be nested together. Likewise, the filter assemblies stack and nest. The vertical portion  72  and second horizontal portion  74  of one filter assembly  40  will fit over the vertical portion  72  and second horizontal portion  74  of a second filter assembly  40  permitting the rings  48  of the two filter assemblies  40  to be nested with and engage each other. 
         [0037]    Next, a filter assembly  40  and a cup  10  are removed from the respective stacks. The filter assembly  40  is inserted into the cup  10  and snapped in place. Specifically, the ring  48  of the filter assembly is nested between the bottom  14  and filter assembly support ledge  22  of the cup  10  with the vertical portion  72  of the filter assembly  40  extending toward the rim  18  of the cup  10 . Next, the ingredients (e.g., the dried coffee) are deposited in the cup  10  over the filter assembly  40 . Using heat, the lid  80  is bonded to the rim  18  of the cup to complete the package. When the style of cup shown in  FIG. 4  is employed, the cup  10  and filter assembly  40  may be preassembled and stacked. This is because when two such assemblies are nested together, the vertical portion  72  and horizontal portion  74  of the filter assembly  10  of one such assembly will fit within the second chamber  36  of the projection  32  formed in the bottom  14  of the cup  10  of the other assembly. One simply takes one of these assemblies, fills it with coffee (or other desired ingredients) and then attaches the lid  80 . 
         [0038]    In addition to being compostable and biodegradable, the packages described above offer several specific advantages when brewing beverages in a single serve brewer such as a Keurig coffee brewer. First, the size and shape of the cup  10  may be adapted to mate with the brewer. Second, such brewers typically have needles which must penetrate the package. As illustrated in  FIGS. 4 and 5 , the brewer includes a needle  100  which pierces the lid  80  and is used to inject hot water into the package. The brewer includes a needle  102  which pierces the bottom  14  of the cup  10  to extract brewed beverage that has passed through the filter assembly  40 . One of the functions performed by the ring  48  of the filter assembly  40  is to reinforce the bottom  14  so that the needle  102  will penetrate the bottom  14  rather than crumple the cup  10 . Third, such brewers are designed to produce a beverage serving of a known size, typically  10  fluid ounces. While a flat filter will often become occluded with grounds and sludge before a full  10  ounces of the beverage has flowed through the filter, by providing a filter assembly  40  having a vertical filter portion  72  of adequate height and a second horizontal filter portion  74 , this problem is avoided. The height of the vertical portion  72  may be adjusted to accommodate different serving sizes (the larger the serving size, the taller the vertical portion) and the characteristics of the material used to brew the beverage. Fourth, the problem of “filter blow-out” is eliminated. This problem occurs when a filter becomes occluded and pressure within the cup causes the filter to rupture. Rupturing of the filter prevents the filter from keeping grounds and sludge separate from the beverage to be consumed. The vertical and second horizontal portions of the filter provide an overflow mechanism which prevents filter blowout from occurring. Fifth, PLA is somewhat fragile compared to plastics typically used to form cups for brewing packaging. The ribs shown in the drawing prevent package rupture at typical brewing pressures and also assist (rather than interfere) with stacking. 
         [0039]    In summary, the described embodiments provide a package which addresses the environmental concerns of the packages most commonly used in the prior art. Likewise, problems related to filtration and strength which have plagued earlier attempts to provide a successful biodegradable and compostable brewing package are solved by the invention embodied as described above. 
         [0040]    Those skilled in the art will recognize that various modifications may be made to the embodiments described above without deviating from the invention. Therefore, the invention is not limited by those embodiments, but only by the following claims to which a reasonable range of equivalents are to be afforded.