Abstract:
A coffee-making machine includes: a nozzle from which an airborne stream of liquid containing coffee extract is ejected under pressure, a funnel downstream of the nozzle for receiving the ejected coffee extract and draining it substantially without retention, and a frothing member positioned in or upstream of the funnel and against which the airborne stream of liquid from the nozzle impinges directly and by which air is entrained in the liquid.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     The present invention relates to coffee brewing machines. More particularly, although not exclusively, the invention relates to a domestic appliance capable of producing a hot liquid coffee beverage having a layer of fine bubbles or coffee crème at its surface.  
         [0002]     Many coffee drinkers enjoy coffee having a layer of coffee crème at the liquid surface. This is a layer of fine bubbled froth produced by the coffee extract in hot water. This is to be distinguished from frothed milk as might be applied to café latte or cappuccino for example. Coffee beverages purchased from commercial establishments usually have a crème layer and this is perceived as an indication of a high quality coffee.  
         [0003]     It is very difficult to achieve a crème layer when brewing one&#39;s own coffee at home or in the office without use of expensive commercial equipment.  
       OBJECTS OF THE INVENTION  
       [0004]     It is an object of the present invention to overcome or substantially ameliorate the above disadvantage and/or more generally to provide an improved coffee machine with a crème production facility.  
       DISCLOSURE OF THE INVENTION  
       [0005]     There is disclosed herein a coffee-making machine, comprising:  
         [0006]     a nozzle from which an airborne stream of liquid containing coffee extract is ejected under pressure,  
         [0007]     a funnel downstream of the nozzle for receiving the ejected coffee extract and draining it substantially without retention, and  
         [0008]     a frothing member positioned in or upstream of the funnel and against which the airborne stream of liquid from the nozzle impinges directly and by which air is entrained in the liquid.  
         [0009]     Preferably, the coffee-making machine further comprises a spout that extends from the funnel and through which the liquid is dispensed.  
         [0010]     Preferably, the coffee-making machine further comprises a chamber upstream of the nozzle and into which a ground coffee-containing pouch is received.  
         [0011]     Preferably, the frothing member comprises a plate having an aperture therethrough.  
         [0012]     Alternatively, the frothing member comprises a plate having a plurality of apertures therethrough.  
         [0013]     Preferably, the frothing member in attached to or formed integrally with the funnel.  
         [0014]     Preferably, the frothing member is detachable from the funnel.  
         [0015]     Preferably, the plate extends normally to the stream of liquid ejected by the nozzle.  
         [0016]     There is further disclosed herein a coffee-making machine, comprising:  
         [0017]     a nozzle through which a stream of liquid containing coffee extract is ejected under pressure, the nozzle having an air-entry aperture through which air enters the nozzle to mix with the stream of liquid as it passes through the nozzle. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     Preferred forms of the present invention will now be described by way of example with reference to the accompanying drawings, wherein:  
         [0019]      FIG. 1  which is a schematic cross-sectional elevation of the key components of a coffee-making machine that are relevant for the production of a coffee crème layer in a cup of coffee produced by the machine, and  
         [0020]      FIG. 2  is a schematic cross-sectional elevation of an alternative apparatus for the production of a coffee crème layer. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0021]     In  FIG. 1  of the accompanying drawing there is depicted schematically a coffee-making machine  10  and a cup  11  to which the coffee beverage is to be dispensed. Many components of the machine are not depicted in the drawing because they are known in the art. Some of these features include a liquid reservoir, a heater for heating water from the reservoir and an electric pump for pumping the water under pressure to a delivery line  12 .  
         [0022]     The delivery line  12  delivers hot pressurised water to a sealed chamber  13  in which a paper-encased ground coffee pouch  14  is received. A closure mechanism (not shown) seals the chamber  13 .  
         [0023]     In the bottom of the chamber there is provided a small nozzle  15  from which coffee extract-containing heated water is ejected downwardly in a vertical stream. This stream is directed into a space containing air, hence the stream can be said to be “airborne”. The nozzle is small in diameter (typically about 0.8 mm) and serves two fundamental functions. The first function is to produce the high-velocity liquid jet and the second function is to regulate the flow rate of water through the chamber  13 . This obviates the requirement for a mechanical or optical flow-metering device in or upstream of the delivery line  12  to deactivate the pump when the cup  11  is anticipated to be full. In the present embodiment, a simple digital timer deactivates the pump when the cup is near-full.  
         [0024]     Situated beneath the chamber  13  is a funnel  16  having an outlet spout  17  via which the coffee beverage is dispensed to the cup  11 .  
         [0025]     Located within the funnel  16  and surrounded by air is a frothing member  18  that extends upwardly from the floor  21  of the funnel  16 . In the depicted embodiment, the frothing member comprises a flat horizontal plate  19  having a plurality of vertical apertures  20  therethrough. The frothing member might be moulded integrally with the funnel  16 , or manufactured as a separate attachment. Manufacturing the frothing member as a separate attachment simplifies moulding of the combined funnel and frothing member. Also, if the frothing member is detachable from the funnel  16  it can be easily removed for cleaning, or removed by users who do not wish to make coffee with a crème layer. To facilitate removal, the frothing member might slot into the funnel  16 , or be attached thereto by screws or other fastening devices.  
         [0026]     In use, heated water is pumped via the delivery line  12  through the chamber  13  whereupon coffee extract from the ground coffee beans within the pouch  14  forms a liquid jet upon passing from the nozzle  15 . This liquid jet passes through the airspace and impinges forcefully and downwardly upon the plate  19  of the frothing member  18 . Some of the liquid jet will be forced through at least one of the vertical apertures  20  and some of the liquid jet will deflect from the upper surface of the plate  19  and fall into the funnel  16 . The frothing member will never be submerged as the funnel is designed to pass liquid immediately to the cup without retaining it. The upper opening of the funnel is sealed and therefore any splashes of liquid will not escape through the top of the funnel to the surrounding bench space. The liquid jet undergoes significant turbulence and sheer forces as it encounters the frothing member. This results in the formation of fine bubbles which are then carried away with the flow of liquid across the floor  21  of the funnel  16  and then through the spout  17  to the cup  11  to thereby create a coffee crème layer upon the coffee in the cup  11 .  
         [0027]     The frothing member would typically be made of hard plastics material, stainless steel or brass for example.  
         [0028]     It could be formed as a moulding, casting or pressing, or might be in the form of a single- or multiple-layered mesh.  
         [0029]     In  FIG. 2  there is depicted an alternative embodiment which does not rely upon a frothing member against which the airborne stream of liquid from the nozzle impinges. Instead, the nozzle  15  is formed as a spray head having a small aperture. When the coffee extract exits the nozzle  15  it forms a fine spray  21  which then forms a foam layer upon the floor  21  of the funnel and then flows under gravity through the spout  17  for dispensation to form a crème.  
         [0030]     It should be appreciated that modifications and alterations obvious to those skilled in the art are not to be considered as beyond the scope of the present invention. For example, rather than being a fixed structure, the frothing member might be made movable, such as for example by being rotatably mounted upon an axle, or resiliently mounted upon a spring. Furthermore, instead of being attached to the funnel, the frothing member might depend from the bottom surface of the pressure chamber. It might even be formed integrally with the nozzle.