Abstract:
A single cup brewer for use in brewing coffee or the like with water in the cup. The brewer comprises a chamber formed by a deformable elastic cover and a base, the cover being attachable to and detachable from the base to form the chamber. The base is adapted to rest on the cup and to support a filter for supporting the coffee within the chamber. The user successively deforms and releases the cover to cause water in the cup to move repeatedly from the cup through the filter and coffee into the chamber and back to the cup again to complete the brewing process.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS 
       [0001]    This application claims the benefit of Provisional Patent Application Ser. No. 61/011,917, filed on Jan. 22, 2008, the disclosure of which is incorporated in its entirety hereinto by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    It has long been desired to provide a quick and easy method and apparatus to brew a single cup of coffee in a similar way to brewing a single cup of tea using an infusion bag. However, it is well known that simply putting ground coffee into an infusion bag, such as a tea bag, and immersing it in a cup of hot water extracts the coffee very slowly. Even dragging the bag back and forth does not move water through the interior of the bag fast enough to percolate through the mass of ground coffee particles in a reasonable time. Entrapped air also hinders the penetration of water significantly. Nevertheless, single cup infusion bags of coffee are currently being sold. However, these infusion bags contain, in addition to ground coffee, a considerable fraction of soluble coffee, also known as instant coffee. The soluble fraction is extracted relatively quickly. Soluble coffee is generally considered to produce an inferior beverage. 
         [0003]    Prior art attempts using hand driven methods to speed up the extraction of ground coffee by forcibly moving water through infusion bags and other porous chambers containing ground coffee provide insufficient flow rate either into the chamber or out of the chamber or both. The more successful attempts have been based on electrically powered motorized countertop brewers, which greatly complicate and add significant cost to the brewing process. 
         [0004]    It is therefore a main object of the invention to provide a hand driven single cup coffee brewer which is simple in makeup and construction, low in cost and easy to use. 
         [0005]    A further object is to provide a single cup coffee brewer which operates to put the hot water used in brewing under pressure in order to increase its rate of flow as it passes through the ground particles of coffee. 
         [0006]    A yet further object of the invention is the provision of a single cup brewer which operates in conjunction with hot water preloaded into a single cup or mug to pump the water from the cup into a brewing chamber and put it under pressure to increase its rate of flow during its passage through the coffee particles. 
         [0007]    A still further object of the invention is to provide an apparatus for repeatedly recycling partly brewed coffee through the brewing chamber a selected number of times to successively increase the strength of the resultant coffee brew. 
         [0008]    A further object is to provide an apparatus suitable for the above purposes that is simple to use, clean and store in a typical kitchen drawer or office desk drawer. 
       BRIEF SUMMARY OF THE INVENTION 
       [0009]    The above noted and other objects of the invention are accomplished by a brewer comprising a brewing chamber adapted to rest on the rim of a cup or mug to allow a user manually to pump hot water from the cup into and out of the brewing chamber and through coffee particles located in the path of the circulating water. The objects of the invention are also accomplished by the associated method. The brewer in turn includes an elastic cover that is attachable to and detachable from a base to close and open the brewing chamber for cleaning and recharging with fresh ground coffee. A filter is supported on the base in a manner such that when the chamber is open the user may insert coffee grains into the chamber on the filter. The base also includes an opening below the filter which is coupled to a dip tube that extends into the hot water in the cup when the base rests on the rim of cup. When the base is resting on the cup and the elastic cover is attached to the base (thereby closing the chamber), downward manual pressure on the cover moves fluid from the chamber, through the filter, and into the cup through the opening and dip tube. Release of the cover allows it to return to its previous shape to move water from the cup, through the dip tube and opening and filter back into the chamber for a repeat of the process upon subsequent pumping of the elastic cover. 
         [0010]    Variants of the invention include means for altering the circulation of liquid in the brewer by means of valves and by means of controlling the resistance to flows in the various directions through the brewer, means for pivoting the dip tube, and means for employing pre-manufactured coffee pods in the brewer. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0011]    A complete understanding of the present invention will be had by reference to the accompanying drawings, when considered in conjunction with the subsequent, detailed description, in which: 
           [0012]      FIG. 1  is a sectional view of the brewer of the invention holding ground coffee resting on top of a cup also shown in section holding hot water used in the brewing process; 
           [0013]      FIG. 2  is a sectional view, similar to  FIG. 1 , showing an alternative construction for the base of the brewer; 
           [0014]      FIG. 3  is a sectional view, similar to  FIG. 2 , showing an additional alternative valve construction for the base of the brewer of the invention; 
           [0015]      FIG. 4  is a sectional view of a pivotal dip tube for use in the brewer of the invention; 
           [0016]      FIG. 5  is a sectional view of a removable filter basket inserted in a modified base; 
           [0017]      FIG. 6  is a sectional view of the brewer containing a coffee pod and adaptor for use with the pod; and 
           [0018]      FIG. 7  is a top view of the base holding a coffee pod adaptor and pod. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    Referring to  FIG. 1 , there is shown an infusion device or brewer  10  suitable for brewing a single cup of coffee, tea, cocoa, herbs, seasonings, and the like. The brewer  10  comprises a base  13  and a cover  25 . The cover  25  comprises a deformable dome  12  held within an annular retaining ring  14  The deformable dome  12  is preferably an elastomer that retains its elasticity in hot water and is a poor conductor of heat. The elastomer is a natural or synthetic rubber, preferably silicone rubber because of its substantial temperature insensitivity over the temperatures encountered. Alternatives to a deformable elastomer include a bellows or a piston/cylinder arrangement. The circular in cross-section cover  25  is attachable to and detachable from the base  13  by means of one of several well known complimentary formations  15 , such a threads or the like, on the base  13  and the retaining ring  14 . Other fastening means such a snap fits, bayonet lugs, hinged lids, or similar coupling means may be used. 
         [0020]    The base  13  also supports a circularly shaped filter  21  by means of a multiplicity of cone shaped or pointed bosses  22  rising from the floor  23  of the base into contact with the underside of the filter. The bosses  22  collectively form a low-pressure-drop pathway or network of channels for the bidirectional flow of fluid to and from the brewing chamber  11 , which is the volume bounded by the interior of the cap and the interior of the base above the filter. The brewing chamber  11  may be opened to expose its interior by unscrewing the cover  25  from the base  13 . The base  13  also includes an opening  26  there through which is coupled to a dip tube or similar elongated conduit  24 . The dip tube  24  extends from the base to below the surface of the water in the cup  20  and is fluidically connected to the pathway formed by the bosses  22  located below and adjacent the underside of the filter  21 . For clarity, ground coffee  27  is shown on the filter  21  within the brew chamber  11 . 
         [0021]    The base  13 , the retaining ring  14 , and the dip tube  24  are made of suitable plastic or filled plastic that maintains adequate stiffness in contact with hot water, such as polypropylene, ABS, SAN, and polycarbonate. 
         [0022]    It is desirable that the brewer  10  of the invention be easily stored in a kitchen drawer of shallow depth and, for this purpose, the dip tube is preferably pivotable to a position flat against the underside of the base  13  for compactness and further to permit ground coffee to be scooped into the chamber  11  when the base is not resting on a cup. 
         [0023]      FIG. 4  shows, in section, a pivotable dip tube  50  which may be used with the brewer of the invention. The pivotable dip tube  50  and its connection to a modified base  51  are shown as viewed from the right side of the device. The dip tube and modified base are shaped so as to permit relative rotation of the elongated tube  50  from a position perpendicular to the plane of the base  51  to a position substantially parallel to the plane of the base. An O-ring  52  is employed as a sealing surface against which the dip tube  50  is rotated. An exemplary pivotable tube is of the type used in dispensing caps for lotions and creams currently on the market, and specifically, as used in the cap of the Rubbermaid Litterless Juice Box Model 3115. As an alternative to being pivoted, the dip tube may be designed to be collapsed, folded, telescoped, or simply removed. 
         [0024]    Examples of suitable filter media include woven monofilament cloth, wire cloth, fabric (both woven and non-woven), filter paper, and porous plastic, metal and ceramic. Fragile and flexible filters may need support on their upper and lower surfaces. The filter  21  may be permanently attached to the base as in  FIG. 1  or it may be removable, as shown in  FIG. 5 , where it is part of a basket  63  consisting of a supporting ring  60  attached to the periphery of the filter  21  itself, plus stiffening members  61  attached to the underside of the filter and to the supporting ring. The base  13  for the removable filter basket  63  does not need bosses rising from its floor because the stiffening members  61  additionally provide the space under the filter for fluid flow. 
         [0025]    A preferred filter medium is fine woven screen, whether made of metal, ceramic, or fabric. The screen should have a finer mesh (smaller openings) than the screens that are commonly used with such coffee brewing devices as plunger pots (French presses) and drip coffeemakers, whether of the cone or basket type. The finer mesh is preferable because, unlike plunger presses and drip brewers in which the bed of coffee particles, once formed, is self-filtering to a significant degree, in the embodiments of the current invention shown in  FIGS. 1 and 5 , the bed is repetitively stirred up and reformed, providing greater opportunity for fine particles to be rinsed through the screen. Moreover, for all the embodiments of the current invention the loading of ground coffee per unit area of screen is lower than it is typically in plunger presses and drip brewers. The lower loading allows faster filtration but also provides more opportunity for fine particles to pass through. In a prototype of the current invention, a screen having 0.001 inch holes showed comparable pass through of fines as a screen having 0.01 inch holes used in the conventional manner in a drip brewer. A source of suitable filter material is Sefar America Inc. 
         [0026]    In operation, the brewer  10  in  FIG. 1  is first cleaned and readied for reuse by unscrewing the cover  25  from the base  13 , discarding any coffee grounds that may be remaining in the chamber  11  from prior use, and rinsing the interior of the chamber  11  and base. The chamber  11  is charged by scooping or pouring loose ground coffee onto the top of filter  21  and the cover  25  is screwed back on the base to close the brewing chamber  11 . The brewer  10  is then rested on a cup of hot water with the base resting on the rim  17  of the cup such that the dip tube is inside the cup. 
         [0027]    The brewing process then begins by simply pushing down on the cover  12  or by gripping the brewer with both hands, thumbs on the cover, fingers under the lip of the base  13 . To provide more area for finger contact, the base or cover may be designed to have side extensions (not shown). 
         [0028]    In operation, the first squeeze or push down of the elastically deformable dome  12  expels air from the chamber  11 , through the bed of coffee, filter, opening  26  and dip tube  24  into the cup of water. Upon release of the dome, water is sucked up into the dip tube, distributed to and through the interconnected passages formed by the upstanding bosses adjacent the underside of the filter, and passes through the filter into contact with the ground coffee particles. As the water flows into contact with the coffee particles, it disrupts the coffee bed and suspends coffee particles in the water accumulating in the chamber  11 . It would be preferable for the user to allow the particles to dwell, suspended in the water for a short time while they settle by gravity back onto the filter. The second squeeze of the cover  12  by the user forces the liquid in the reverse direction, from the brew chamber  11  back into the cup. The coffee particles, now partially extracted by their temporary suspension in the hot water in the chamber, are reformed into a bed of substantially uniform depth on the dome side of the filter as the water is re-circulated back to the cup through the coffee bed and the network of passages beneath the filter. The second release of the dome by the user draws partially brewed coffee from the cup back into the brew chamber, again disrupting the bed of particles into suspension, thereby furthering the flavor extraction process, which process is enhanced as the successive cycles are performed. 
         [0029]    Additional squeeze/release cycles increase the strength of the brewed coffee. When the desired strength is reached, the device is lifted away from the cup followed by an optional squeeze or two of the dome to discharge any residual liquid from the chamber  11  into the cup. 
         [0030]    In a variant of the above described device, conceptually shown in  FIG. 2 , the rate of liquid intake from the cup is increased by partially bypassing the filter with a less restricted fluid pathway as by the use of a check valve  30  which allows faster recovery of the dome  12  to its undeformed shape. In this variant, the pathway contains a check valve  30  which, in addition to allowing water to pass more easily from the cup to the chamber, also reduces the rate of outflow of water from the chamber during squeezing. Although a duckbill check valve is shown in  FIG. 2 , alternatives include flapper valves, umbrella valves, and ball check valves. 
         [0031]    The bypass is particularly advantageous with filters having small holes which tends to restrict the flow of air when wetted. For such wetted filters, a critical pressure drop, known as the bubble point, is required to begin the flow of air (or other gas). The smaller the holes in the filter, the larger the pressure drop required. This effect comes into play in the current invention during the final discharge of liquid, referred to above, when the device is lifted from the cup and squeezed a few times. Air is sucked in to replace the discharged liquid. With screens having the small holes (e.g., 0.001 inch) as preferred, the incoming air will tend to be blocked by the wetted filter screen, resulting in the device being effectively “airlocked”. The bypass avoids this airlocking. 
         [0032]    Another variant, shown in  FIG. 3 , employs two check valves  35  and  40  to enable full separation of the intake and discharge pathways. By so doing, the discharge pathway is not immersed in the cup. Specifically, the air or liquid discharged from the chamber through the dip tube and into the body of the liquid on the squeeze portion of the brewing cycle in the apparatus of  FIG. 1 , is instead discharged above the surface of the liquid in the cup through the valve  40 , thereby eliminating the possibility of liquid overflowing the cup during the first squeeze when air expelled from the device can bubble up vigorously if discharged below the surface of the liquid. The two check valve variant shown in  FIG. 3  promotes unidirectional flow by reducing remixing of the bed, thereby permitting the use of filter screens with larger holes. 
         [0033]    Other variants may be designed for use with pre-manufactured single serve coffee pods, in which a predetermined amount of ground coffee, typically about 8 grams, is sandwiched between two layers of filter paper laminated at their edges to form a circular lip around the rim of the pod. The pods are intended for use in companion motorized electrical appliances that pump hot water through them into the user&#39;s cup. If one of these pods is simply loaded into one of the above embodiments of the current invention in place of a corresponding amount of loose ground coffee, brewing will be inefficient because water will significantly bypass the pod. Bypassing can be reduced by using an adaptor in the base or cover that seals around the outer periphery of the pod and thereby forces water in the chamber through the pod, as shown in  FIGS. 6 and 7 .  FIG. 6  is otherwise identical to  FIG. 1  except for the replacement of the loose coffee grounds  27  with the coffee pod adaptor  70  and the coffee pod  71 . The adaptor is made of plastic or preferably closed cell elastomeric foam. It is held against the pod  71  and the base  16  by the cover  25 . The inflowing liquid from the cup passes into the chamber through the hole  72  and the open one-way valve  73  in the adaptor  70 . Exiting liquid leaving the chamber would be blocked from flowing back through the hole  72  by the check valve  73  to force water from the chamber through the coffee in the pod on its return to the cup. 
         [0034]    The embodiment shown in  FIGS. 6 and 7  may be further modified for use with pods only, not for use with loose ground coffee, by replacing the filter screen with a less costly, more open support filter screen having much larger holes i.e., of the order of 0.125 inches. 
         [0035]    The preceding description has presented in detail an exemplary preferred embodiment of the invention and its application. While the description has been primarily directed to brewing coffee with the described apparatus, it should be clear to those skilled in the art that it is equally suitable for making flavorful beverages/drinks, such as tea, seasonings and the like, from other solid particulate material by the same or similar processes and apparatus as shown herein. Those skilled in the art will therefore recognize that numerous alternatives encompassing many variations may readily be employed without departing from the scope of the present invention as set forth in the claims herein.