Patent Application
20060174771
The present invention refers to an assembly for creating milk froth and for heating milk, comprising a foaming device including a steam supply channel, an air supply channel, a milk supply channel, and a discharge opening.
For creating milk froth, so-called milk foaming devices or emulsifying devices are known in various embodiments. Usually, these milk foaming devices or emulsifying devices comprise a steam supply channel, opening into a suction chamber. The suction chamber communicates with a milk supply channel and an air supply channel. By means of the steam flow, a negative pressure is created in the suction chamber, said negative pressure causes milk to flow via the milk supply channel into the suction chamber and air to flow via the air supply channel into the suction chamber. The so created mixture of steam, air and milk is brought into a turbulent flow in a subsequent emulsifying chamber, with the result that a homogenous milk froth is created. The milk froth created by such a foaming device can be used, for example, for preparing a Cappuccino beverage or a “Latte Macchiato” beverage. Besides creating milk froth, such a foaming device usually can also be used to heat milk, whereby in such a case the supply of air is interrupted.
The publication EP 0,195,750 discloses an emulsifier unit particularly for emulsifying steam and milk to prepare “cappuccino's”. The emulsifier comprises a nozzle body member, connected to a steam generator. The nozzle body member is inserted into a tubular body member, opening tangentially into a cylindrical emulsifying chamber. The latter one comprises, at its bottom, a discharge opening. In the interior of the tubular body member, a suction chamber is created into which opens, at its top, an air supply inlet and, at its bottom, a milk supply inlet. Upon feeding steam into the suction chamber, a negative pressure is created therein, causing the aspiration of milk and air. The mixture of water, steam, air and milk is tangentially fed into the emulsifying chamber in which it is brought into a turbulent flow, which supports the emulsifying process and causes the steam to condensate. The so created emulsion leaves the device through the discharge opening.
It is an object of the invention to provide an assembly for creating milk froth and for heating milk that is of simple straight-forward design. It is a further object of the invention to provide an assembly for creating milk froth and for heating milk in which milk residues in the foaming device can quickly be drained after the creation of milk froth or the heating of milk has been done.
To meet these and other objects, the present invention provides an assembly for creating milk froth and for heating milk, comprising a foaming device including a steam supply channel, an air supply channel, a milk supply channel, a discharge opening, and a valve assembly. The foaming device further comprises a venting channel by means of which the foaming device is vented after milk foam has been created or milk has been heated. The valve assembly comprises means for selectively closing the venting channel and the air supply channel, depending on the mode of operation of the assembly.
In the following, an embodiment of the assembly according to the invention will be further described, with reference to the accompanying drawings, in which:
The assembly for creating milk froth and for heating milk is designated, as a whole, by reference numeral 1. Essentially, the assembly 1 comprises a foaming device 2, a milk container 3, a coupling element 4 as well as a valve assembly 5. Moreover, a cover 3a for closing the milk container 3 is shown in the drawing.
The foaming device 2 comprises a lower portion 6, an upper portion 7 and a valve insert 8, the elements 6 and 7 being attached to each other by means of a push-fit connection. Furthermore, a valve insert 8 is illustrated in
At the top of the foaming device 2, the valve assembly 5 is located. The valve assembly comprises a silicon mat 28, the bottom side thereof being provided with two protruding closure elements 29, 30 by means of which the air supply channel 15 and the venting channel 22 can be sealed at their opening end. The top side of the silicon mat is provided with two embossments 31, 32, located correspondingly with regard to the closure elements 29, 30. The opening and closing of the valves is performed by means of a cam shaft 35 driven by a stepper motor 34. The cam shaft 35 is provided with three cams 36, 37, 38 by means of which the two closure elements 29, 30 of the silicon mat 28 as well as a further closure body, located at the rear of the valve assembly 5, are actuated. The further closure body 40 is shown in the illustration of
The foaming device 2 is further provided with a trunk-shaped appendage 17, extending towards the bottom of the milk container 3. It contains the milk supply channel 16, and the distal end thereof has an inlet opening 18 communicating with the milk supply channel 16. The appendage 17 is provided, in the region of its inlet opening 18, with two diametrically opposite, radially extending cutouts 19, which favor the entry of milk from the milk container 3 into the appendage 17. At the inlet of the steam supply channel 14, a cylindrical recess 44 is provided in the foaming device 2. The outlet opening 21 opens into a cylindrical recess 45, too.
The coupling element 4 is provided with two cylindrical stubs 46, 47, the distance between the two stubs 46, 47 corresponding to the distance between the two cylindrical recesses 44, 45, and the outer diameter thereof matching the diameter of the two cylindrical recesses 44, 45 to enable a leak proof plug and socket connection between the particular stub 46 and 47, respectively, and the particular recesses 44 and 45, respectively. The two cylindrical stubs communicate in each case via a bore 50 and 51, respectively, with a connecting flange 48 and 49, respectively. Thereby, the upper connecting flange 48 is adapted to receive a hose (not shown) running to a steam source (not shown), while the lower connecting flange 49 is adapted to receive a hose (not shown) running to a beverage outlet (not shown).
The mode of operation of the assembly 1 can be explained as follows:
In order to produce foamed milk, the closure element 29 located at the inlet of the air supply channel 15 is displaced into its open position, while the closure element 30 located at the inlet of the venting channel 22 is displaced to its closed position. This condition is schematically shown in
For ending the milk foam production, the supply of steam is stopped, with the result that the pressure in the negative pressure chamber 24 raises and the check valve 26 closes. After the milk having been foamed, the closure element 30 closing the venting channel 22 is displaced into its open position; thereby, any milk residues still present in the foaming device 2 are drained thereof. Again, displacing the closure element 30 into its open position is performed by triggering the stepper motor 34, rotating the cam shaft 35 into the corresponding position. By venting the foaming device 2, and in the case where the milk discharge opening is located below the milk container 3, it is simultaneously avoided that milk can continue to flow out of the milk container 3 under the influence of the principle of communicating tubes.
For warming or heating milk, both the closure element 29 located at the inlet of the air supply channel 15 and the closure element 30 located at the inlet of the venting channel 22 are brought into their closed positions. Thereafter, again via the steam supply channel 14, steam is supplied, flowing through the nozzle 23 into the mixing channel 25. The negative pressure zone in the region of the nozzle 23, generated by the flowing steam, results in sucking in milk into the milk supply channel 16 via the appendage 17; however, air is prevented to flow into the horizontally extending portion 16a of the milk supply channel 16. In this way, milk can be heated quickly and easily.
In order to ensure that the milk-containing duct portions, bores and channels 16, 16a, 24, 25, 51 are drained after a foaming or heating cycle, the closure element 30 located at the inlet of the venting channel 22 is brought into its open position after each operation cycle.
Preferably, all channels of the foaming device are provided with a surface constituted by nano-particles, being both hydrophobic and oleophobic and in which at least some of the nanoparticles consist at least partially of silver or a silver compound. By providing such a surface, the foaming device 2 is easy to clean and, additionally, provides anti-microbial activity. With the expression “nano-particles”, particles should be understood that have a dimension of between 10−10 to 10−7 m, preferably approximately 10−8 m.
Even if the assembly is relatively unsusceptible to contamination, it should be cleaned regularly. This can be performed either by means of a flushing program in which at least the ducts, bores and channels 16, 21, 24, 25, 45, 51, which are critical as far as contamination is concerned, are flushed with hot water. Or, another possibility consists in manually removing the coupling element 4 from the foaming device 2 and to lift the foaming device 2 off the milk container 3. Thereafter, the upper portion 7 of the foaming device 2 can be pulled off the lower portion 6 with the result that the inner parts of the foaming device, which are critical as far as contamination is concerned, particularly the horizontally extending portion 16a of the milk supply channel 16 as well as the nozzle 23 and the negative pressure chamber 24, are exposed. Alike, the valve insert 9 can be removed. The afore mentioned parts and elements then can be cleaned in a dish washer.
| Number | Date | Country | Kind |
|---|---|---|---|
| 00194/05 | Feb 2005 | CH | national |
