Foaming unit for foaming milk or milk / air mixture and beverage making machine including the above.

Abstract

The present invention relates to a foaming unit for foaming milk or a milk / air mixture, the foaming unit having a steam supply line, a milk supply line, a mixing unit having a first flow region and a second flow region, and an outlet line having an outlet opening for milk foam, the outlet line being connected to the second flow region.

Description

Technical Field

[0001] The present invention relates to a foaming unit for foaming milk or a milk / air mixture, the foaming unit having a steam nozzle, a milk supply line, a mixing unit having a first flow region and a second flow region, and an outlet line having an outlet opening for milk foam, the outlet line being connected to the second flow region. Background Technology

[0002] Various foaming systems are known in the prior art, in which milk is drawn in via the Venturi effect generated by steam, heated by the condensation of steam, and then rotated with air in a foaming chamber to produce milk foam. Such systems are described in DE4445436 C2, EP 2229851 B1, and EP 1785074B1. To improve the accuracy of milk dispensing, hoses or gear pumps are used to draw in the milk.

[0003] However, these Venturi effect-based systems have the drawback of fluctuations in milk yield and foam quality, as some fluctuations can occur when using the Venturi effect. Furthermore, the system requires a separate foaming chamber.

[0004] Other systems known in the prior art use a driven agitator to foam a mixture of milk, air, and steam (EP 2326224 B1). In foaming systems with a gear pump, the gear also functions as an agitator to foam the milk, air, and steam mixture. However, systems with a driven agitator require more equipment and are less easy to clean due to the various components, leading to higher hygiene risks and cleaning work. The pump housing and gear form the foaming chamber in the system.

[0005] Furthermore, there exist systems in which a mixture of milk, air, and steam is forced through a nozzle under pressure by a pump, and then foams downstream of the nozzle due to a pressure drop. Such systems are known from EP 2294952B1 and EP 3649904A1.

[0006] In these systems, the nozzles must be cleaned during the time-consuming process to prevent buildup and clogging during pauses. This can negatively impact foam formation or cause significant fluctuations in foam quality.

[0007] There are also static mixers, to which air, milk, and steam are mixed to produce milk foam (EP 2042063A1). Although static mixers have no moving parts, they have a large number of corners, edges, and dead zones, which are also very difficult to clean. Summary of the Invention

[0008] Therefore, the purpose of this invention is to provide a foaming unit that eliminates the disadvantages of the prior art and can achieve uniform foam quality while reducing equipment costs and cleaning requirements.

[0009] This objective is achieved by a foaming unit having the features of claim 1 and a beverage making machine having the features of claim 16. Further dependent claims show advantageous further embodiments.

[0010] According to the present invention, a foaming unit for foaming milk or a milk / air mixture is provided, the foaming unit comprising the following components:

[0011] A steam supply line for supplying steam or a steam-air mixture, comprising a steam nozzle with a nozzle outlet.

[0012] Milk supply lines used to supply milk or a mixture of milk and air.

[0013] The hybrid unit, in the form of a hollow profile, includes a first flow region with an inner cross-sectional area and a second flow region with an inner cross-sectional area, wherein the inner cross-sectional area of ​​the second flow region is smaller than that of the first flow region.

[0014] The outlet pipeline, which is directly adjacent to the second flow area, has an outlet opening for milk foaming.

[0015] The hybrid unit is designed in the form of a hollow profile, particularly a flexible tube or pipe. The hollow profile has a defined internal cross-sectional area.

[0016] The steam supply line, milk supply line and mixing unit are connected to each other via connecting elements, particularly tee connecting elements, preferably T-shaped elements, and the steam nozzles are axially aligned with the mixing unit.

[0017] Steam / air and milk are combined in a connecting element. An air-steam jet is supplied to the connecting element through a nozzle, and milk is supplied perpendicular to the connecting element. Alternatively, air may be supplied to the milk instead of steam, or air may be supplied to both milk and steam.

[0018] In the subsequent first flow zone, a uniform milk sheath flow surrounds the steam jet, which has a high velocity relative to the milk, thus forcing even the smallest bubbles into the milk. The milk / air mixture is heated by the condensation of the steam. In the mixing unit, a second flow zone with a smaller cross-section relative to the first flow zone occurs, where further mixing and homogenization of the foam takes place.

[0019] Using the foaming unit according to the invention, a simple device structure consisting of connecting elements and a steam nozzle can be realized, wherein the foaming unit does not require an additional motor or moving parts. Furthermore, the use of a foaming chamber can be eliminated. The foaming unit according to the invention is also an easy-to-clean unit.

[0020] The steam nozzle is preferably axially positioned in the connecting element relative to the steam supply line, with the nozzle outlet arranged in the region of the milk supply line such that the steam jet is cylindrically surrounded by the sheath flow of milk in the first flow region of the mixing unit. The nozzle outlet is preferably arranged downstream of the steam flow, but it can also be arranged in an extension at the center of the milk supply line.

[0021] In a preferred embodiment, the first flow region has a diameter of 7 to 20 mm. 2 The inner cross-sectional area within the range and / or the length within the range of 20 to 100 mm and / or the second flow zone having a length of 3 to 7 mm 2 The range of inner cross-sectional area and / or the range of 100 to 1200 mm, preferably the range of 300 to 700 mm.

[0022] Preferably, the ratio of the inner cross-sectional area of ​​the second flow region to the inner cross-sectional area of ​​the first flow region is preferably 1:1 to 1:7, more preferably 1:1.5 to 1:4, and / or the ratio of the length of the first flow region to the length of the second flow region is preferably 1:1 to 1:60, more preferably 1:5 to 1:20.

[0023] Furthermore, it is preferred that the first flow region and the second flow region are formed integrally, or that the first flow region and the second flow region are connected to each other using connecting elements, especially two-way connecting elements or three-way connecting elements, preferably T-shaped elements.

[0024] The foaming unit preferably has at least one temperature sensor that can determine the temperature of the milk and / or steam. The at least one temperature sensor may be directly disposed on the connecting element between the first and second flow zones or downstream of said connecting element. Temperature determination is used to set or achieve a predetermined target temperature for the milk foam. If the temperature is too low, the pump rate for conveying the milk is reduced to direct more steam into the milk. If the temperature is too high, the pump rate for conveying the milk is increased. Alternatively, the amount of steam can be varied via a valve in the steam supply line. The steam-to-milk ratio is adjusted in this way.

[0025] In a preferred embodiment, the milk supply line and mixing unit are made of hoses, which are preferably made of plastic, and particularly preferably of a fluoropolymer, specifically selected from PTFE, PFA, FEP and combinations thereof.

[0026] The hybrid unit preferably has a cylindrical, rectangular, or elliptical cross-section.

[0027] Preferably, a pump for conveying milk is arranged in the milk supply pipeline.

[0028] The steam supply line is preferably connected to the steam generating unit and / or valves for controlling the steam flow are arranged in the steam supply line.

[0029] The milk supply line is preferably connected to a milk container or to a container for cleaning solution.

[0030] Preferably, the outlet pipeline has an inner diameter that widens in the direction of the outlet opening, and particularly preferably has a tapered geometry.

[0031] The outlet line is preferably made of thermoplastic or elastomeric plastic. For example, thermoplastic or elastomeric plastics approved for use in food contact under regulations (EC) No. 1935 / 2004 and (EU) No. 10 / 2011, particularly polyvinylidene fluoride (PVDF), polypropylene (PP), polyoxymethylene (POM), or silicone, are preferred. Preferably, the outlet line has a length in the range of 40 to 80 mm and / or an inner diameter in the range of 2 to 4 mm at the end adjacent to the mixing unit and / or an inner diameter in the range of 3 to 8 mm at the outlet opening.

[0032] Furthermore, it is preferred that the outlet pipeline is arranged substantially perpendicular to the mixing unit, particularly preferably at a 90° angle, and the end of the outlet pipeline adjacent to the mixing unit serves as an impact surface.

[0033] To ensure a uniform flow of milk or foam without splashing, the milk or foam passes through the outlet pipe last. This preferably begins at a 90° angle, which serves as an impact surface. This is followed by a tapered section with a cross-section that widens towards the outlet pipe. The 90° angle is advantageous for the overall result, but it is not mandatory. It is used to shorten the outlet pipe.

[0034] The outlet line is used to generate a layered milk foam jet with a low flow rate, so that when the milk foam is dispensed, i.e., when the milk foam hits the bottom of the cup, no more air bubbles are introduced into the milk foam due to turbulence or splashing. The air bubbles will be quite large and noticeably accumulate at the top of the milk foam.

[0035] The foaming unit according to the invention is characterized in that it eliminates the need for the foaming chamber used in the prior art, resulting in a significant reduction in equipment costs.

[0036] According to the present invention, a beverage making machine, particularly a coffee machine, having the aforementioned foaming unit is also provided. Therefore, the beverage making machine does not require a separate foaming chamber. Attached Figure Description

[0037] The bubbling unit according to the invention will be explained in more detail with reference to the following figures, without limiting it to the specific embodiments shown herein.

[0038] Figure 1 A first variation of the foaming unit according to the invention is shown;

[0039] Figure 2 Another variation of the bubbling unit with a temperature sensor according to the present invention is shown;

[0040] Figure 3 A third variation of the bubbling unit with a temperature sensor according to the present invention is shown. Detailed Implementation

[0041] Figure 1 A foaming unit 1 is shown, whose central element constitutes a mixing unit 5 having a first flow region 6 and a second flow region 7.

[0042] The first flow zone 6 is connected to the steam generating unit 13 via a steam supply line 2. The steam supply line 2 also has a valve 12 for controlling the steam flow. The steam supply line 2 is connected to the first flow zone 6 via a tee connector 10, wherein the steam flow is guided into the first flow zone through a nozzle 3 having a nozzle outlet 3a.

[0043] The milk supply line 4 leading to the milk container 14 is connected via another branch of the tee connector 10. The pump 11 is used to deliver milk from the milk container 14 through the milk supply line 4 to the tee connector 10. The milk supply line 4 is now connected substantially vertically to the steam nozzle 3, which surrounds the steam stream flowing from the nozzle outlet 3a as a sheath flow and guides the steam stream through the first flow zone 6. Due to the high relative velocity of the steam jet with respect to the supplied milk, even the smallest bubbles are forced into the milk, causing foaming. The condensation of the steam causes the milk / air mixture to heat up.

[0044] The design of the mixing unit makes the diameter of the first flow region 6 narrower relative to the second flow region 7 at the connection 16 between the first flow region 6 and the second flow region 7. This narrowing creates flow resistance and allows the milk foam to be further mixed and homogenized in the second flow region 7.

[0045] The resulting foam is then guided to a beverage container 20, such as a cup, through an outlet pipe 8 having an outlet opening 9. Here, the outlet pipe has a tapered structure with a widened cross-section, which allows the foam to be evenly distributed without splashing.

[0046] As an alternative Figure 1The possibility of connecting a container with cleaning fluid 15 instead of milk container 14 is shown. This allows the cleaning fluid, instead of milk, to be directed to the mixing unit 5 via milk supply line 4, which allows the system to be cleaned in a simple manner.

[0047] Figure 2 The variant shown basically corresponds to the one based on Figure 1 A variant thereof, wherein a connecting element 16 is arranged at the junction from the first flow region 6 to the second flow region 7, the connecting element additionally having a temperature sensor 17 for determining the temperature of the milk foam at the transition from the first flow region 6 to the second flow region 7.

[0048] Figure 3 The variant shown basically corresponds to the one based on Figure 2 The structure is modified such that the transition from the first flow region 6 to the second flow region 7 is achieved via a three-way connector 16. A temperature sensor for determining the milk foam temperature is arranged on the third branch of the connector 16.

Claims

1. A foaming unit (1) for foaming milk or a milk / air mixture, comprising: A steam supply line (2) for supplying steam or a steam-air mixture, comprising a steam nozzle (3) having a nozzle outlet (3a). Milk supply lines (4) for supplying milk or a mixture of milk and air. The hybrid unit (5) is in the form of a hollow profile, comprising a first flow region (6) having an inner cross-sectional area and a second flow region (7) having an inner cross-sectional area, wherein the inner cross-sectional area of ​​the second flow region (7) is smaller than the inner cross-sectional area of ​​the first flow region (6). The outlet pipeline (8), which is directly adjacent to the second flow area (7), has an outlet opening (9) for milk foaming. The steam supply line (2), the milk supply line (4) and the mixing unit (5) are connected to each other via a three-way connector (10), and the steam nozzle (3) is axially aligned with the mixing unit (5). Its features are, The milk supply line (4) and the mixing unit (5) are made of flexible tubing. The first flow region (6) has a length ranging from 20 to 100 mm. The second flow region (7) has a length in the range of 100 to 1200 mm.

2. The foaming unit (1) according to claim 1. Its features are, The steam nozzle (3) is axially aligned with the steam supply line (2) in the tee connector (10), wherein the nozzle outlet (3a) is arranged in the region of the milk supply line (4) such that in the first flow region (6) of the mixing unit (5), the steam jet is cylindrically surrounded by the sheath flow of milk.

3. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The tee connector (10) is a T-shaped component.

4. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The first flow region (6) has a diameter of 7 to 20 mm. 2 The area of ​​the inner cross section within the range, And / or the second flow region (7) has 3 to 7 mm 2 The area of ​​the inner cross section within the range.

5. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The ratio of the inner cross-sectional area of ​​the second flow region (7) to the inner cross-sectional area of ​​the first flow region (6) is 1:1 to 1:

7. And / or the ratio of the length of the first flow region (6) to the length of the second flow region (7) is 1:1 to 1:

60.

6. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The first flow region (6) and the second flow region (7) are integrally formed, or the first flow region (6) and the second flow region (7) are connected by a connecting element (16).

7. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The foaming unit (1) has at least one temperature sensor (17) which can determine the temperature of milk and / or steam, wherein the temperature sensor (17) is arranged directly on the connecting element (16) between the first and second flow areas or arranged downstream of the connecting element (16).

8. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The hoses of the milk supply line (4) and the mixing unit (5) are made of plastic.

9. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The hybrid unit (5) has a cylindrical, rectangular or elliptical cross-section.

10. The foaming unit (1) according to any one of claims 1 or 2. Its features are, A pump (11) for conveying milk is arranged in the milk supply line (4).

11. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The steam supply line (2) is connected to the steam generating unit (13), and a valve (12) for controlling the steam flow is arranged in the steam supply line (2).

12. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The milk supply line (4) can be connected to a milk container (14) or to a container (15) for cleaning liquid.

13. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The outlet pipeline (8) has an inner diameter that widens in the direction of the outlet opening (9).

14. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The outlet pipeline (8) has a length in the range of 40 to 80 mm and / or an inner diameter in the range of 2 to 4 mm at the end adjacent to the mixing unit (5) and / or an inner diameter in the range of 3 to 8 mm at the outlet opening (9).

15. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The outlet pipeline (8) is arranged perpendicular to the mixing unit (5), and the end of the outlet pipeline (8) adjacent to the mixing unit (5) serves as an impact surface.

16. The foaming unit (1) according to any one of claims 1 or 2. Its features are, The foaming unit (1) does not have a foaming chamber.

17. A beverage making machine, characterized in that, The beverage making machine includes a foaming unit according to any one of claims 1 to 16.

18. The beverage making machine according to claim 17, Its features are, The beverage making machine does not have a foaming chamber.

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