Field of the invention

The present invention relates to a machine preparing beverages by mixing a beverage ingredient and a diluent.

Background of the invention

WO 2008/071613 describes a mixing chamber for preparing frothed beverages wherein a dose of a beverage soluble ingredient is mixed with a diluent. Such a mixing chamber is particularly adapted for preparing a frothed coffee beverage from soluble instant coffee. The mixing chamber provides sufficient agitation with the water to dissolve and froth the coffee. At the end of the coffee preparation a simple rinsing of the chamber with water is sufficient to evacuate any residue of coffee and clean the chamber before the preparation of a new coffee.

It has been observed that such a mixing chamber is not adapted for the preparation of beverages comprising a dairy component such as mixture of instant coffee, dairy product and sugar usually called 3-in-1 coffee mixes. Actually the production of such a beverage with the mixing chamber of the prior art creates a frothed beverage but residues frequently stay in the chamber at the end of the preparation. Due to the presence of dairy components these residues cannot be accepted for hygiene reasons.

Consequently there is a need for improving the rinsing of such a mixing chamber in particular for being able to use it with soluble beverage ingredients comprising dairy components it is not possible to use spray-dried instant coffee with the above machine.

Summary of the invention

According to a first aspect, the invention concerns a mixing chamber for producing a beverage comprising :

- a chamber with a transverse bottom wall, a longitudinal upward wall,

- at last one diluent inlet provided through the upward wall,

- at least one beverage delivery outlet provided through the bottom wall,

wherein :

- the chamber comprises an embossed zone at the surface of the longitudinal upward wall, said embossed zone facing the diluent inlet. The chamber can take various shapes. In a preferred mode, the longitudinal upward wall is substantially cylindrical. The wall is such that its longitudinal distance (or height) is longer than its diameter (or width) in order to ensure that liquid does not flow over the chamber when being impacted and circulated by effect of the jet of diluent. Other shapes could be envisaged such as a polygonal, e.g., hexagonal, or oval section of the chamber, for instance.

According to the invention, the bottom wall comprises one liquid outlet or a plurality of liquid outlets.

Preferably, the upward wall is substantially vertical to promote liquid draining. The device has proved to be self-cleaning in the sense that substantially no solid, residue or beverage foam is left in the chamber after operation. The diluent can rinse the inner surfaces of the chamber. So liquid or solids residue can evacuate entirely to the outlet(s). Indeed, it is important to be able to fully drain and rinse the chamber in order to keep it clean and avoid hygiene issues.

The chamber is deprived of any actuated elements like blades or a whipper. A zone of the surface of the longitudinal upward wall of the chamber is embossed, said zone facing the diluent inlet. So the embossed zone is positioned so as to face the diluent inlet on the wall surface opposed to the diluent inlet.

Preferably the embossed zone presents a design configured for creating a diluent mist when a jet of diluent hits said embossed zone, in particular when a jet of diluent hits said embossed zone essentially perpendicularly to the surface of said zone.

According to a particular embodiment the design of the embossed zone comprises pyramid shape elements rising from the chamber upward wall and placed next to another. By "pyramid shape element" it is understood a polyhedron of which base is a polygon and presenting sides that are triangles which meet at the top (the apex).

The pyramid shape elements are positioned one to the other so that, when the diluent jet hits one face of the pyramids, it is divided in several sub-jets oriented in different directions and able to hit next pyramids faces where sub-jets are themselves sub-divided. The phenomenon is reproduced creating a mist of diluent.

Preferably all the pyramid shape elements present the same shape, yet the invention can also be implemented with pyramid elements of different shapes and sizes.

Preferably each pyramid is asymmetric, its top being slightly inclined upwardly. This configuration provides an upper movement to the created diluent mist which is able to spread up to the top cover of the chamber and to clean all the volume of the chamber. The chamber is preferably designed for preparing a single dose of beverage for a consumer that is the chamber preferably presents an internal volume comprised between 8 and 15 cm ³ . According to the preferred embodiment the chamber presents a cylindrical shape with a height comprised between 70 and 90 mm and a diameter comprised between 40 and 50 mm. For a chamber presenting a diameter comprised between 40 and 50 mm, the embossed zone generally presents a surface of at least 1 cm ² . According to this preferred embodiment the diluent inlet is a diluent nozzle presenting an outlet diameter comprised between 0,2 and 1 mm, preferably between 0,3 and 0,8 mm and even more preferably between 0,4 and 0,6 mm. According to the preferred embodiment the diluent inlet is oriented according to a longitudinal axis inside the chamber and the embossed zone is positioned on said longitudinal axis. Then the diluent jet issued from the diluent inlet hits the embossed zone.

According to a particular embodiment the longitudinal axis of the diluent inlet can be inclined downwardly, preferably according to an angle comprised between 5 and 30°.

Preferably the diluent inlet is oriented along a longitudinal axis inside the chamber and said axis is offset relative to the longitudinal central axis of the chamber.

Preferably the embossed zone is positioned next to the bottom of the longitudinal upward wall. This configuration enables the rinsing of the whole volume of the chamber with the diluent mist.

According to the preferred embodiment the mixing chamber can be molded in a plastic material and the embossed zone can be molded with the chamber. The diluent inlet can also be molded with the chamber.

According to the preferred mode the top of the chamber is covered by an openable cover. According to the preferred embodiment the bottom face of the openable cover is concave. This shape is configured for enabling the diluent drops of the mist that deposit on the cover bottom surface to flow on said surface and to be guided to the edge of the cover and subsequently to flow along the lateral walls of the chamber. Consequently effective rinsing of the chamber walls and cover can be reached.

According to a second less preferred mode of the invention the chamber does not present a cover but cooperates with a beverage production machine that provides a cover on the chamber when it is positioned inside the machine. The bottom of said cover is preferably concave.

According to another embodiment the mixing chamber can comprise a handle. An operator can take said handle to hold the chamber and remove it from a beverage production machine.

According to a second aspect, the invention concerns a beverage production machine comprising the mixing chamber such as described hereabove and comprising diluent feed means which is connectable to the diluent inlet.

According to the invention, the diluent can be any suitable liquid adapted for dissolving a beverage soluble ingredient using the features and conditions of the device. A preferred diluent is water either hot or cold. Generally the diluent supply of the beverage production machine comprises at least a diluent tank, a diluent pump, a diluent heater and a valve for actuating the diluent delivery. It can also comprise a selection valve for delivering either hot or ambient temperature diluent.

Preferably the beverage production machine can comprise a receiving area for removable positioning the mixing chamber and for connecting the mixing chamber diluent inlet to said diluent supply.

According to the second mode of the invention the top of the mixing chamber is deprived of any cover and consequently the upper part of the receiving area is configured for forming a cover above the mixing chamber when it is positioned in the receiving area. Preferably the upper part of the receiving area configured for forming a cover above the mixing chamber presents a concave bottom face.

According to said second mode the beverage production machine can comprise a beverage soluble ingredient dosing unit placed above the top opening of the chamber to feed it with powder. The dosing unit can be associated to a powder reservoir. Feeding by the powder dosing unit can be automatically controlled without handling of the powder. In another mode, the dosing unit can be associated to a liquid concentrate reservoir. The machine can comprise a set of at least two mixing chambers configured for mixing different soluble beverage ingredients. In particular the chambers can differ by the shape and the size of their beverage outlets. For example a mixing chamber for the preparation of a beverage presenting an important beverage size, like a 3 in 1 beverage, presents a larger surface for outlet(s) than a mixing chamber for the preparation of a foamed beverage presenting a smaller beverage size, like a coffee espresso. The size or surface section of the outlet(s) enables to keep the beverage in the chamber longer wherein the foaming can be increased.

According to a third aspect the invention concerns a method for producing a beverage with a beverage production machine such as described hereabove comprising the steps of :

- introducing a soluble ingredient in the chamber,

- introducing a diluent through the diluent inlet.

In particular, according to the first mode of the present invention, when the machine comprises a mixing chamber, the top of the chamber being covered by an openable cover, the step of introducing soluble ingredient in the chamber can consist in :

- removing the mixing chamber from the receiving area of the machine,

- opening the cover of the mixing chamber and introducing a soluble beverage ingredient inside,

- closing the cover and positioning the mixing chamber in the receiving area of the machine.

The dosing of the ingredient can be made manually with a spoon and a beverage ingredient jar. Yet preferably the content of a stick pack is introduced in the mixing chamber. This embodiment provides a more consistent beverage preparation since the amount of ingredient is always the same.

The diluent is preferably introduced through the diluent inlet so that a jet of diluent is created in the mixing chamber with a high velocity so that the diluent jet issued from the nozzle crosses the chamber and hits the embossed zone.

In particular in the preferred embodiment of a cylindrical chamber presenting a diameter comprised between 40 mm and 50 mm and a diluent inlet nozzle presenting and outlet diameter comprised between 0,2 and 1 ,0 mm, the delivery of water at a pressure of at least 6 bar in the nozzle enables the production of a jet of velocity sufficient to hit the embossed zone and to create the mist. Even more particularly for a chamber diameter comprised between 40 mm and 50 mm and a diluent inlet nozzle presenting and outlet diameter comprised between 0,4 and 0,5 mm, water is introduced in the nozzle at a pressure of about 7,5 bar. The diameter of the diluent nozzle outlet, the diameter of the chamber, the flow rate of the diluent are generally adapted accordingly to get the mist effect when water jet hits the embossed zone.

Preferably the diluent is introduced in the diluent inlet during such a time length that the soluble beverage ingredient is dissolved and the mixing chamber is rinsed. During the introduction of the diluent, in a first step the soluble beverage ingredient is dissolved and the resulting produced beverage is dispensed through the outlet, and in a second step the chamber is rinsed.

The soluble beverage ingredient can be any beverage ingredient selected in the list of soluble coffee powder, chocolate powder, milk powder and mixtures thereof. Mixtures of sugar, instant coffee and milk powder known as coffee mixes are preferred. Other soluble powder ingredients like soluble tea, dehydrated culinary ingredients and/or milk based ingredients can be used. The device and the method of the present invention are applicable too to the dissolution of liquid concentrates with a diluent. Such liquid concentrates may be coffee, chocolate or milk concentrates.

Brief description of the drawings

The characteristics and advantages of the invention will be better understood in relation to the following figures :

- Figure 1 is a schematic view of a beverage production machine comprising a chamber according to the invention,

- Figure 2 is a side view of a mixing chamber according to the present invention,

- Figure 3 a top view of the mixing chamber of Figure 2 without the cover,

- Figure 4 is a longitudinal section view of the mixing chamber of Figure 2,

- Figure 5 is a section view of the mixing chamber of Figure 2 according to XX',

- Figure 6a is a magnified view of the embossed zone of the mixing chamber of Figure 2,

- Figure 6b is a longitudinal section view of the embossed zone,

- Figure 6c is a top view of the embossed zone,

- Figures 7a and 7b are bottom views of the beverage outlet of an alternative mixing chamber according to the invention. Detailed description of the drawings

Referring to Figure 1 , a beverage production machine 1 is represented that includes a mixing chamber 2 of the invention for producing a beverage from a soluble beverage ingredient and a diluent entering the device.

A diluent feed circuit is provided in the machine to be able to feed the mixing chamber 2 with diluent, more particularly, hot water. For that, a water reservoir 1 1 is provided that can be replenished with fresh water. A water pump 10 transports the diluent from the reservoir 1 1 to a water heating system 9 such as a thermoblock or a cartridge type heater and to eventually a non-return valve 14. The pump can be any type of pump such as a piston pump, diaphragm pump or a peristaltic pump. Finally water is fed into the device by a tube 8.

As illustrated in figure 1 , the mixing chamber 2 can be placed directly above a service tray 14 onto which is placed a drinking cup to receive the beverage liquid. Generally the mixing chamber 2 is removable from the machine for cleaning and optionally for dosing. The machine comprises a mixing chamber receiving area 7 to fix the chamber inside and provide cooperation between the mixing chamber diluent inlet 4 and the machine diluent supply tube 8.

According to a less preferred embodiment the beverage production machine can comprise a reservoir 15 of soluble beverage ingredient 17 coupled with a dosing system 16. The mixing chamber can be movable to a position placed under said dosing system as described in WO 2009/153157. The dosing system has the primary function to meter upon request doses of ingredient into the mixing chamber. The reservoir 15 can be a hopper which is permanent or a disposable package containing the soluble ingredient. The dosing system 16 can be any suitable system such as a dosing screw, a reciprocating dosing piston or a rotating disc. The dosing technology is also of course dependent on the nature of the soluble ingredient. The soluble ingredient is typically a dry beverage powder. However, it could also be a liquid concentrate. The device is fed upon request with ingredient manually or automatically as prompted by a controller 12 and command 13. One can notice that the reservoir and dosing system are optional in the machine. Therefore, the device is preferably fed manually by removing the chamber 2 from the machine and introducing a soluble beverage ingredient in the chamber using a scoop or pouring the content of a stick pack in the chamber.

A controller 12 can be further provided to introduce diluent in the chamber or coordinate dosing of the soluble beverage ingredient by the dosing system 4 and diluent by the pump 6 upon the user actuating or being prompted to press a command 13 on the machine. Figures 2 to 5 illustrate a mixing chamber 2 according to the present invention. In Figure 2 dotted lines relate to elements that are not visible from outside. The chamber is cylindrical and presents a transverse bottom wall 21 and a longitudinal upward wall 22 forming the body of the chamber. The body of the chamber does not present any wall at its top but its top is covered by an openable cover 3. The cover is attached to the chamber body by a hinge 31. As illustrated in Figure 4 the bottom face 32 of the cover is concave. The chamber comprises at least one beverage delivery outlet 5 provided through the bottom wall. As illustrated in Figures 4 and 5 the beverage delivery outlet can be composed of several holes 51 in the centre of the chamber bottom wall. Usually the number of holes, their positions and their surfaces is defined according to the type of soluble beverage ingredient that is prepared in the chamber. In particular these features can depend from the solubility of the beverage ingredient and the volume of beverage ingredient introduced in the chamber. As an example the preparation of a white coffee from a 3- in-1 coffee mix requires a large quantity of powder which, when introduced in the mixing chamber, fills at least half the volume of the chamber. As soon as the beverage is produced it should be evacuated to avoid overflow ; then numerous beverage outlets holes are provided.

The chamber comprises one diluent inlet 4 provided through the upward wall 22. The longitudinal axis YY' of the diluent inlet that defines the direction of the diluent jet inside the chamber is inclined downwardly. Besides, said longitudinal axis YY' is offset relative to the longitudinal central axis O of the chamber. According to the preferred embodiment the diluent inlet is a pipe presenting a diameter comprised between 0,4 and 0,6 mm. It is preferably molded with the chamber body.

A zone 6 of the surface of the longitudinal upward wall 22 of the chamber is embossed. This embossed zone 6 is positioned so as to face the diluent inlet 4 on the wall surface opposed to the diluent inlet. Then the longitudinal axis Y of the diluent inlet crosses at least a part of the embossed zone 6 as illustrated in Figures 2 and 4.

Figures 6a, 6b and 6c are magnified views and sections of the embossed zone 6 according to the preferred embodiment of the present invention. The design of the embossed zone 6 comprises similar pyramid shape elements 61 rising from the chamber upward wall 22 and placed next to another. Pyramids present fours triangular side faces. The faces of the pyramids are oriented so as to divide the jet of diluent striking the embossed zone in several sub-jets oriented in different directions and able to hit next pyramids. Preferably the pyramids are aligned with one triangular side face 61a facing the top of the chamber. As illustrated in Figure 6b, said top face 61 a is preferably less inclined than the bottom face 61 b of the pyramid. As illustrated in Figure 6c, one lateral face 61 d is preferably less inclined than the other lateral face 61 e of the pyramid ; as a consequence the apexes 61 c of the pyramids 61 are slightly laterally inclined too. These asymmetries of the pyramids can help for dispersing the mist in the whole chamber. Actually as mentioned hereabove since the longitudinal axis YY' of the diluent jet is inclined downwardly and is offset relative to the longitudinal central axis O of the chamber, the asymmetries enable the reorientation of the mist to the centre of the chamber and to its top.

The embossed zone 6 is preferably placed next to the bottom of the lateral wall 22. Then the mist of diluent can spread upwardly through all the volume of the chamber.

The chamber may have a diameter of from 40 and 50 mm for beverage systems of relatively small size. Even larger chambers can be envisaged for example for beverage machines offering greater delivery capacity.

Figures 7a an 7b illustrate an alternative design for the outlets at the bottom of the mixing chamber according to the present invention. The outlets are in form of slots 51 and are large enough to enable a rapid evacuation of the beverage from the chamber as soon as it is produced. Three ribs 52 are positioned between two side-by-side slots in order to gently guide the beverage to a drinking receptacle.

When a beverage is prepared by means of the mixing chamber of Figures 2 to 6 a dose of soluble beverage ingredient is introduced in the chamber by removing the chamber from the machine, by opening the cover 3 and introducing a dose of beverage ingredient inside the chamber. For this operation the customer can remove the chamber from the beverage machine by pulling the chamber out of the machine, opening the cover and throwing at least one spoon of a beverage ingredient or the content of a stick pack in the chamber. The cover is then closed and the chamber replaced inside the mixing chamber receiving area 7 of the machine so that the diluent inlet of the chamber cooperates with the diluent supply means 8 of the machine.

Then the preparation of the beverage is launched by introducing the diluent inside the chamber through the diluent inlet 4. The diluent is introduced in the diluent inlet 4 with such a flow that a diluent jet of high velocity is created inside the chamber. In order to obtain a jet of diluent that reaches a sufficient velocity and therefore sufficient kinetic energy providing high shear forces to dissolve the beverage ingredient inside the chamber and also hits on the embossed zone, the diameter of the diluent nozzle outlet, the diameter of the chamber and the flow rate of the diluent are adapted accordingly. As an example good results have been obtained for a chamber diameter comprised between 40 and 50 mm, a diluent inlet nozzle comprised between 0,45 and 0,5 mm and with the supply of water at about 7,5 bar by the water pump : a water flow rate of about 270 ml/min was obtained that was sufficient to dissolve the soluble beverage ingredient in the chamber and create a mist in the chamber when the jet hits the embossed zone.

The diluent mixes with the beverage ingredient powder and dissolves it. The orientation of the diluent inlet can be optimised to improve the mixing as detailed in WO 2008/071613. The beverage issued from the dissolution is evacuated from the beverage outlet 5 in a drinking cup placed in the area 14 of the machine. The introduction of the diluent goes on after the powder has been totally dissolved so as to clean the chamber : the jet of diluent hits the embossed zone which creates a mist of diluent which spreads out through all the internal volume of the chamber. When the mist reaches the top of the chamber it is stopped by the cover 3 on which mist drops settle. The concave orientation of the cover 3 enables the diluent drops to slide from the cover to the top of the lateral wall 22 of the chamber as illustrated by the arrows A in Figure 4. Then the diluent flows on the surface of the cover, on the lateral wall and on the bottom wall, rinses them and is evacuated through the outlet 5. The contact between the cover and the top edge of the chamber is usually sufficient to prevent diluent mist from escaping from the chamber but it usually does not isolate the chamber from the atmosphere. According to the less preferred embodiment of the present invention wherein the mixing chamber is automatically dosed by a dosing system 16 rather than manually, the mixing chamber 2 can present the same feature as the mixing chamber of Figures 2 to 6 except that it does not present a cover 6 attached to the chamber body. Actually for automatic dosing the mixing chamber shall remain opened when it is moved to the dosing position. Consequently the machine presents a chamber receiving area 7 configured for forming a cover above the mixing chamber when the mixing chamber is positioned at the mixing position. The bottom of the cover is preferably concave.