Abstract:
The present invention relates to drink-stirring device for stirring or mixing liquid and/or powdered ingredients with liquid in a drinking vessel ( 4 ), the liquid being supplied from above through the stirring device to an outlet tube which conducts at least one liquid jet towards the interior of the drinking vessel. The liquid is supplied through an outlet tube ( 64 ) which is rotatably attached to the device and is associated to an external, magnetic member ( 82 ). The electromagnet arrangement is arranged outside or at distance of the magnetic member for creating a variable magnetic field configured to move the tube ( 64 ) in rotation, so that the emerging liquid jet can be given a corresponding centrifugal effect.

Description:
BACKGROUND 
   The present invention relates to a drink-stirring device for stirring or mixing liquid and/or powdered ingredients with liquid in a drinking vessel. The invention also relates to a method for stirring, and eventually foaming, a liquid in a drinking vessel. Stirring devices of this kind are used in apparatus for the retail sale of drinks consisting of a usually hot liquid and liquid or powdered concentrate. 
   It has often been difficult for previously known stirring devices to bring about satisfactory mixing of the other ingredients with the liquid. Particular problems arise when it is desirable to bring about frothing of liquid, for example when preparing cappuccino. This is usually carried out now by frothing milk in a separate vessel. This vessel has to be washed several times a day for reasons of hygiene. EP 1 197 145 describes a device for frothing milk for preparing cappuccino consisting of a tubular device with a through-spindle with stirring blade, an inlet for steam at the top and inlet openings for air and milk along the tube. This is an expensive and complicated stirring device of great overall height, and furthermore it cannot prepare the whole drink but only the milk froth. It is generally the case that two stirring devices are required for making cappuccino. 
   It is known to use permanent magnets in mixing vessels, these magnets being caused to rotate by means of an outer rotating or pole-changing magnetic field. WO 85/05046 discloses such a device comprising a mixing vessel with a bottom outlet. Arranged round the lower edge of the vessel is a closed iron core with a number of electric coils connected to an alternating current source, which can produce magnetic fields of varying frequency and strength. The device is used especially for mixing in connection with chemical processes. 
   EP 0 285 210 describes a drink mixer comprising a tube-like mixing vessel with a bottom outlet. Arranged in the mixing vessel is a mixer blade, which has at the bottom a magnetic member in the form of a permanent magnet. Arranged outside the vessel is an electromagnet, which can set the mixer blade in rotating and/or vibrating motion. The mixer blade is exposed in the mixing vessel and can easily be lifted out for cleaning. Cleaning nevertheless remains a laborious and time-consuming operation. The mixer blade can be provided with slits in order to bring about frothing of the drink, for example when preparing cappuccino. Cleaning is then even more laborious. 
   EP 1 155 646 discloses a device for preparing a drink in a cup, into which powdered ingredients have first been introduced. Liquid for diluting the drink is supplied through a distributing head arranged on a vertical hollow shank attached to a drive wheel. At the top, the shank is connected to an inlet tube via a freely rotatable coupling. The distributing head comprises a diagonally extending connecting line, which leads to two opposite, eccentrically positioned, downwardly directed distributing nozzles. The drive wheel is arranged in a gearbox and is driven by an electric motor. 
   This device has a number of disadvantages. It comprises an extra motor and a mechanical transmission to the distributing head via gearwheels. This leads to wear and a risk of breakdown. The freely rotating connection between the tube and the hollow shank is also subjected to wear and, over time, suffers liquid leakage. The winding liquid passages in the distributing head are also difficult of access for cleaning, and scale can be expected to be deposited in these. 
   SUMMARY 
   The object of the invention is therefore to produce a drink-stirring device comprising a distributing head intended to mix diluting liquid with other ingredients in the drinking vessel itself, which device has a simple and easy-to-clean construction, does not contain any moving parts in the liquid duct, has a small overall height and has few moving parts. It is also to be possible for the device to be used for preparing different kinds of drink with different requirements for stirring during preparation. Another object of the invention is also to indicate a method for the said device for drink preparation, which makes preparation of both frothy and non-frothy drinks possible in the same device. A further object of the invention is to indicate a use of the stirring device for preparing cappuccino and other frothy drinks without using a separate preparation device for frothing milk or other liquid. 
   These objects are achieved by virtue of a drink-stirring device for stirring or mixing liquid and/or powdered ingredients with liquid in a drinking vessel, the liquid being supplied from above through the stirring device to an outlet tube which conducts at least one liquid jet towards the interior of the drinking vessel. The liquid is supplied through an outlet tube. The outlet tube is rotatably attached to the device. The outlet tube is associated to an external, magnetic member. An electromagnet arrangement is arranged outside or at a distance of the magnetic member for creating a variable magnetic field configured to move the outlet tube in rotation. This particular arrangement provides the liquid jet a corresponding centrifugal effect that promotes mixing and/or frothing of the liquid in the vessel. This arrangement is so particularly effective for stirring and frothing a liquid in a drinking vessel. This arrangement also promotes a more hygienic delivery and more hygienic stirring of the drink with reduced contact of the system with the liquid; therefore, requiring less cleaning. This arrangement is also less cumbersome. 
   The invention also relates to a method for stirring a liquid in a drink vessel characterized in that the liquid is conducted through a liquid delivery outlet tube which is rotatable so that the emerging liquid jet can be given a corresponding centrifugal effect. 
   In a possible mode of the method, the speed of rotation of the outlet tube is adjustable by a control unit. Preferably, the rotation of the outlet tube is adjusted at variable speeds as function of the type of drink prepared. This provides the advantage to adjust the pattern of liquid jet to the type of drink being prepared and, in particular, to adjust the amount of foam, for example, for cappuccino drinks. 

   
     BRIEF DESCRIPTION OF THE FIGURES. 
     The invention will now be described with the aid of a non-limiting illustrative embodiment and with reference to the accompanying drawing, in which 
       FIG. 1  shows a diagrammatic view of a drink-making system comprising a stirring device according to the invention shown without encasement, cup magazine and other peripheral equipment; 
       FIG. 2  shows a view at an angle from above of a stirring device according to the invention; 
       FIG. 3  shows a view at an angle from below of the device in  FIG. 2  shown without bottom plate; 
       FIG. 4  shows a sectional vertical view of the device in  FIGS. 2 and 3 ; 
       FIG. 5  shows a view at an angle from below corresponding to  FIG. 3  showing only the housing of the device and a support plate; 
       FIG. 6  shows a view directly from below of the housing in  FIG. 5 ; 
       FIG. 7  shows a plan view from below of a bottom plate belonging to the device in  FIG. 2 ; 
       FIG. 8  shows a side view of the bottom plate in  FIG. 7 ; 
       FIG. 9  shows a side view of an outlet tube forming part of the stirring device, and 
       FIG. 10  shows an exploded diagram of the stirring device in  FIGS. 2-9 . 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a drink preparation system forming part of an apparatus for the retail sale of drinks. For reasons of clarity, only the actual drink preparation system has been shown and not other peripheral equipment and installation components. The system consists of a liquid tank  1 , a connecting tube  2 , a stirring device  3 , which opens above a cup  4  arranged in a cup presenter or cup feed unit of carousel type  5 . The cup presenter is supplied with cups from a magazine (not shown), which cups are then fed under the stirring device  3  after first having had powdered drink ingredients introduced. The powder supply can take place either before the carousel or in a carousel position before the liquid supply. 
   The liquid tank comprises a heating device and has on the outside a valve device  10 . Arranged with the valve device  10  is a pump  12 , which presses the previously measured or defined liquid quantity into the tube  2 . The tube runs via tube holders  14 , only two of which are shown, to an inlet pipe  16  arranged on the stirring device  3 . The pipe  16  is goose-necked and has an inlet part  18  connected to the tube  2  and an outlet part  20  having stop projections  22 , which limit the depth to which the outlet part can penetrate the stirring device  3 . The overall height of the drink preparation system is reduced by virtue of the inlet pipe being goose-necked. 
   The stirring device  3  has a housing  24  and a bottom plate  25 . The housing  24  consists of a surrounding casing  26  with a top  28  and a wall  30  and also a plate or flange  32  projecting from the lower part of the casing. Projecting upwards from the top  28  is a centrally located, conical neck  34 , which is terminated at the top by an inwardly directed flange  36  surrounding a central hole  38  for the inlet pipe  16 . The maximum downward penetration depth of the pipe  16  is limited by the stop projections  22  on the outlet part  20 . At the opposite end, the neck  34  is terminated by an annular flange  40  projecting into the housing. The surrounding wall  30  encloses a central part  31  and three magnet spaces  33  projecting from this. The housing  24  also has on the wall  30  assembly attachments  42  in the form of guide pins, which are intended to be fastened in corresponding holes  58  in the bottom plate, and which can receive assembly screws (not shown) for holding the parts together. 
     FIGS. 5 and 6  show the housing  24  with the magnets removed. A triangular support plate  44  in the form of a circuit board is arranged in the housing. The support plate has a central hole  46 , which surrounds the position-defining, annular flange  40 . The support plate  44  has cutouts  48  in the triangle vertices, which serve as seats for electromagnets  50 . The electromagnets are connected via lines (not shown) to the circuit board plate  44 . Control signals and power are supplied to the electromagnets by lines (not shown), which pass through a hole  52  in the housing  24 . 
   The bottom plate  25  shown in  FIGS. 7 and 8  has a support edge  54  intended to bear against the housing casing  26  and surround three magnet spaces  56 . The bottom plate has in its centre a conical neck  60 , which projects into the annular flange  40 . The neck  60  also has cutouts  62  for the iron cores  51  of the electromagnets  50 . 
   The angled pipe  16  is connected to an outlet tube  64  and is pushed onto the outside of it. The outlet tube  64  has at its upper end  66  two annular beads  68  and  70  with an intermediate region  72 . The outlet part  20  of the angled pipe is intended to be guided over the outlet tube and over the first bead  68  into contact with the second bead  70 , which serves as a stop. The position of the outlet tube in the longitudinal direction is thus defined. Arranged at the lower, outlet end  74  of the outlet tube are two further external beads  76 ,  78  enclosing a wider intermediate region  80  which receives a ring  82  made of ferromagnetic material located on the outside. This ring is located at the same level as the electromagnets  50 . The material of the ring should be such that it does not become permanently magnetized after having been located in a magnetic field, for example transformer sheet or the like. The outlet tube is suitably made from silicone material, which is especially suitable for handling foodstuffs. 
   During use of the stirring device, the electromagnets are activated in turn round the arrangement at the speed corresponding to the desired mixing intensity. The outlet end  74  of the outlet tube  64  and its mouth  84  will then move along an approximately circular path, and the emerging liquid jet will describe a corresponding, closed, approximately circular path in the cup. This movement is made possible by virtue of the neck  34  surrounding the outlet tube and its extension in the neck  60  projecting upwards from the bottom plate having a downwardly increasing width. By virtue of the liquid jet moving over the cup bottom and then round the cup contents, the powdered concentrate will be whirled up and dissolved in the liquid. 
   Depending on the properties of the drink mixed, the speed or frequency of the tube mouth can be varied. 
   The device is especially advantageous for preparing cappuccino, in which connection it is possible to prepare this drink in the drinking vessel itself starting from powdered ingredients and hot water and using a single mixing device. 
   The invention is not limited to the illustrative embodiment shown but can be varied arbitrarily within the scope of the inventive idea as defined by the patent claims which follow. In particular, use can be made of liquid concentrate instead of powder. It is also possible to make drinks other than coffee, for example tea, chocolate and cold drinks such as fruit syrup and water. Furthermore, use can also be made of more than three electromagnets, or the ring made of non-permanent magnetic material can be replaced by a magnetic member. The stirring device can also comprise more than one liquid line, which lines are moved round simultaneously by the electromagnets. This may be for syrup and water, for example. The concentrated liquid to be dissolved is then suitably introduced at the beginning of the mixing cycle or even before it. The invention is not limited to the use of drinking vessels in the form of disposable cups either but can be used together with any drinking vessel, for example one&#39;s own coffee mug. 
   It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope of the present subject matter and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.