RU2812834C1 - Mixing device - Google Patents

Abstract

FIELD: mixers.

SUBSTANCE: invention provides a mixing device having a first opening for receiving milk, a second opening for receiving steam, an air intake duct for receiving air, and a mixing chamber for mixing milk, steam and air. A barrier element is provided at the outlet of the mixing chamber, the barrier element being adjustable to set different degrees of foaming.

EFFECT: choosing between at least two possible types of outlet for foamed milk suitable for different types of drinks.

15 cl, 10 dwg

Description

The present invention relates to the field of automatic preparation of drinks, in particular to the field of automatic preparation of foamed milk drinks.

BACKGROUND OF THE ART

Typically, fully automatic espresso equipment provides automated brewing of coffee with milk foam. In most cases, steam is used to heat and froth the milk, much like a barista would. To improve the usability of the device and ensure consistent performance for all users, regardless of their qualifications, several milk frothing modules have been developed. As a rule, these modules are designed to be removable from the base unit, since all parts in contact with the milk must be cleaned.

The applicant has developed a milk frothing system that contains only two detachable components, allowing it to be easily cleaned by the user. This design is disclosed in WO 2019/129599 and WO 2019/1029515. It is a rodless milk frothing system in which the frothing function is carried out by steam flow. This type of design is less susceptible to fouling than a traditional design that has a rod as an air restriction, and is therefore more reliable in producing foam.

The known system produces one type of frothed milk outlet in response to steam being introduced into the system.

US 2016/0015206 discloses a milk frothing device which includes an obstruction in the path from the steam inlet to the settling chamber.

DE 10 2006043 905 discloses a milk frothing device with a rotating foaming element.

It would be desirable to be able to choose between at least two possible types of foamed milk outlet, for example suitable for different types of drinks.

DISCLOSURE OF THE INVENTION

The present invention is defined in the claims.

According to the examples, in accordance with one aspect of the invention there is provided a mixing device comprising:

the first hole for receiving milk;

second hole for steam intake;

air intake duct for receiving air and

a mixing chamber for mixing milk, steam and air to create foamed milk, wherein the mixing device also includes a barrier element at the outlet of the mixing chamber, the barrier element being adjustable to set different degrees of foaming.

The barrier element is adjustable between at least the first and second positions to set different degrees of foaming. These positions remain static during foaming, so that each static position results in a different degree of foaming.

The barrier element affects the level of liquid in the mixing chamber and the time the mixture remains in the mixing chamber before exiting through the outlet of the mixing chamber. This thus affects the performance of the mixing device. In particular, it has been found that the adjustable barrier element is able to control the degree of foam, which refers to the ratio of foam to milk. The mixing chamber functions as a foaming bath in which milk, steam and air are frothed. The barrier element forms a housing wall which defines the mixing chamber and thus defines the closed volume of the mixing chamber. The barrier can be adjusted between a high (maximum) foam-to-milk ratio and a minimum foam-to-milk ratio. This minimum foam-to-milk ratio can even produce hot milk without foam, in which the degree of foaming is zero or close to zero.

The barrier element does not need to be continuous. In particular, the dynamic, eg circulating movement of milk in the mixing chamber means that even an intermittent barrier may be sufficient to provide the required barrier function.

The mixing device may further include an outlet downstream of the mixing chamber, with a barrier element located in a path between the mixing chamber and the outlet.

Thus, the barrier is located at the outlet of the mixing device. This means that it is easy to implement an adjustable barrier element since the barrier element is not located deep within the internal structure of the mixing device.

The barrier element, for example, includes a projection extending along the entrance to the outlet pipe, and the barrier element is adjustable by rotating the projection. For example, a protrusion has different protrusion heights at different angular positions. The protrusion may extend along the inlet portion of the outlet. Alternatively, the protrusion may be a circular protrusion extending around the entrance to the outlet.

Thus, a simple adjustment of the rotation of the protrusion is used to provide foam control. It is simple and intuitive for the user.

The protrusion may have a first protrusion height and a second, different protrusion height at diametrically opposed protrusion positions. Thus, two positions of the protrusion, spaced 180° apart, give two possible foaming characteristics. One of the protrusion heights may be zero, or they may both be non-zero.

A protrusion, for example, has a set of exactly two discrete protrusion heights. Thus, each projection height extends almost 180 degrees, so that no precision is required to set the projection to the desired one of the two foaming modes.

Instead, the protrusion may have at least three discrete protrusion heights at different angular positions around the protrusion. Thus, there may be three or more foaming modes.

In another example, the protrusion has a continuously varying protrusion height. This allows you to more accurately select the required foaming.

The barrier element may include a recess at the lowest point for each of a set of operative angular positions.

This recess can act as a drain. It is not so large as to interfere with the function of the barrier element, but it allows the mixing chamber to be emptied at the end of use of the mixing device when the circulating flow in the mixing chamber has ceased. Thus, the barrier element does not have to be a continuous element.

The mixing device may include a channel arrangement between the first and second openings and the mixing chamber. The channel layout may contain:

a first channel portion connected between the first hole and the foaming section; a second channel portion connected between the second hole and the foaming section, the foaming section being connected to the mixing chamber; And

air intake duct to the foaming section,

Thus, there is a duct arrangement that brings milk, steam and air together to create heated and frothed milk. Foaming is created by air introduced by the air intake duct and mixing in the mixing chamber.

The mixing device may contain:

a first container containing a channel arrangement;

a second container configured to receive the first container; And

a seal located between the first container and the second container.

This arrangement allows milk and steam to be supplied to the mixing chamber through a channel formed at least in part by the seal. Thus, the channel can be disassembled for cleaning by simply removing the first container from the second container, since the channel arrangement contains only these two separable parts.

In addition, since the channel itself is partially formed by the seal when positioned between the first and second containers, proper sealing of the channel is ensured.

Placing the two containers together provides the desired seal location and/or compression or expansion.

The first container may also include a container extension, wherein a channel arrangement is formed between the container extension and the seal.

In this way, the dimensions of the channel can be controlled by changing the height of the projecting portion of the container, and the need to clean the seal is reduced. The seal, for example, includes a sealing seal.

The present invention also provides a coffee maker comprising: a device for producing liquid coffee extract;

a mixing device as defined above; And

dispensing device configured to dispense:

liquid coffee from a device for obtaining liquid coffee extract and frothed milk from a mixing device.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the present invention will be described in detail below with reference to the accompanying drawings, in which:

in FIG. 1 shows a two-component mixing device;

in FIG. 2A is a detailed exploded view of the mixing device of FIG. 1;

in Fig. 2B shows the mixing device of FIG. 2A assembled;

in FIG. 3A shows a detailed view of the channel of the mixing device of FIG. 2A;

in FIG. 3B shows the fluid flow passing through the channel of FIG. 3A;

in FIG. 4 shows an example of an overlapping seal;

in FIG. 5 shows a mixing device according to the invention in a first operating mode;

in FIG. 6 shows the mixing device of FIG. 5 in section;

in FIG. 7 shows in more detail the structure of the barrier element used in the mixing device of FIG. 5;

in FIG. 8 shows a mixing device according to the invention in a second operating mode;

in FIG. 9 shows the mixing device of FIG. 8 in section; And

in FIG. 10 shows the mixing device of FIG. 5-9 to show how adjustments are made between operating modes.

DETAILED DESCRIPTION OF IMPLEMENTATION OPTIONS

The invention provides a mixing device having a first opening for receiving milk, a second opening for receiving steam, an air intake duct for receiving air, and a mixing chamber for mixing milk, steam and air. A barrier element is provided at the outlet of the mixing chamber, the barrier element being adjustable to set different degrees of foaming.

In FIG. 1 shows a mixing device 100 including a first container 110 and a second container 120 configured to receive the first container 110. The second container may surround the first container, or it may only partially surround the first container, as shown. The second container 120 defines an outlet 122 from which the frothed milk is supplied. Thus, the first container may fit entirely within the second container, or the second container may be snap-attached to the outside of the first container.

A channel arrangement is formed at the interface between the first and second containers, as described in more detail below. Seal 130 provides a seal to the channel arrangement. When the first and second containers are separated, the channel arrangement is revealed. In the illustrated embodiment, the seal 130 is visible on the outside of the second container 120 because in this example it extends entirely through the outer wall of the second container. The visible outer surface of the seal serves no function; on the contrary, it is simply an aesthetic design option. The inner surface of the seal closes the corresponding channel sections of the channel arrangement.

In FIG. 2A shows the mixing device 100 in more detail, and shows a first container 110, a second container 120 configured to receive the first container 110, and a seal 130 located between the first and second containers.

Rather than being integral with the container and extending completely through the wall of the container, the seal may be press-fitted into the side wall of one of the two containers so that when the two containers are assembled, the seal is located between them. In all designs of this general type, the interface between the seal and one of the containers forms a closed channel arrangement that can provide fluid paths for mixing incoming milk, incoming steam, and allowing the frothed milk to exit. By separating the two containers, all parts can be easily cleaned. Preferably, there is only one sealing element to seal the entire channel arrangement used for supplying and mixing milk and steam.

The seal may be incorporated into the second container 120 by two-step (2K) injection molding, or it may be a separate seal that is removable from a recess in the second container.

The channel arrangement 140 may be formed in the first container 110 and, together with the seal 130, may form a closed channel when the mixing device is assembled. In the example shown in FIG. 2A, the first container 110 includes a protruding channel portion 145 that further defines a channel arrangement 140. The channel arrangement 140 connects a first opening 150 near the bottom of the first container and a mixing chamber 160 near the top of the first container. The second container includes a steam inlet (indicated by reference numeral 175 in FIG. 2B) connected to a second opening 170 formed in the seal 130. The channel arrangement 140 further connects the second opening 170 to the first opening 150 and the mixing chamber.

In FIG. 2B shows the mixing device 100 of FIG. 1A in assembled condition. This drawing clearly shows that the second container 120 includes a steam input hole 175 from which steam can be supplied to the second hole 170. The second container 120 further includes a third hole 180, which, when assembled, is connected to the mixing chamber 160 of the first container, resulting in which makes it possible to conveniently obtain the contents of the mixing chamber from the mixing device. The third opening 180 leads to an outlet 122 (not shown in FIG. 2A or 2B, but shown in FIG. 1). The operation of the mixing device is described with reference to FIG. 3A below.

In FIG. 3A shows a detailed view 200 of the channel mixer arrangement 140 of FIG. 2A. In FIG. 3B shows a simplified illustration of the intersection of various portions of the channel arrangement 140.

The channel arrangement 140 may be divided into several sections in accordance with the work performed by each section. During operation, milk may be supplied to the first container 110 and steam may be supplied to the steam inlet 175 of the second container. As steam enters the channel arrangement 140 through the second opening 170, milk 215 is drawn from the first container 110 into the first channel section 210 through the first opening 150. Steam 225 enters the second channel section 220 and passes through the third channel section 230 (hereinafter also referred to as the frothing section). into the mixing chamber 160. The steam flow creates a reduced pressure (relative to ambient pressure) in the third channel section 230, thereby drawing milk 215 along the first channel section 210. The steam is then used to heat the milk and mix the milk with air to create milk foam and thus forms the driving force of the entire foaming system.

Milk 215 is drawn along the first channel section 210 until it encounters the steam flow 225 at the intersection of channel sections 210 and 230. This intersection may be located in the central portion of the third channel section 230, immediately downstream of the throat formed between the second channel section 220 and the beginning of the third channel section 230. At this throat, the steam is significantly accelerated, thereby providing a Venturi effect (a decrease in fluid pressure as a result of a narrowing of the throat) acting on the steam as it passes into the third channel section 230.

In this way, the static absolute steam pressure (which in this example could, for example, be approximately 1.9 bar = 190 kPa) is converted into dynamic pressure (velocity). Milk is absorbed as a result of a decrease in pressure. The steam velocity is highest at the end of the throat, i.e. where the first channel section 210 intersects the third channel section 230. The second part of the third channel section 230, i.e. the area further downstream from the throat and the aforementioned intersection can be considered to function as a diffuser in which the speed of the milk and steam mixture is slowed down, converting the dynamic pressure back to static pressure.

The third channel portion 230 terminates at an end 235 that is open to the mixing chamber 160. At the end 235 immediately upstream of the mixing chamber, an air intake passage is formed through which air is introduced into the milk/steam mixture. The flow rate of the milk/steam mixture near the air intake duct is such that the static pressure is still lower than the ambient pressure, so that air is drawn in and the milk/steam mixture is prevented from leaking. The introduced air creates bubbles for the desired foaming.

In the mixing chamber 160, the mixture of milk, steam and air reaches ambient static pressure and the velocity component or dynamic pressure returns to zero. Thus, the steam experiences the Venturi effect at the throat. This is the leading (active) effect, controlling the flow of milk as a slave (passive) effect. This Venturi effect in the third channel section 230 can be achieved by simply limiting the cross-sectional area of the third channel section 230 relative to the second channel section 220. The flow of milk and steam in the third channel section in combination with air suction determines the foaming of the mixing device, and pressure differences prevent leakage milk and steam through the wrong channels. Thus, the third channel section can be considered as a foaming section. In particular, the geometry of the channels determines the relationships between steam, milk and air, and these ingredients are combined in the third channel section.

The mixing chamber froths these ingredients to create frothed milk and also releases excess air. Thus, mixing chamber 160 is where the actual foaming occurs. Foaming depends on the geometry of the mixing chamber.

The first channel portion may generally be vertical in use and extend upward from the first (milk inlet) opening 150. In the upper part, on one side it can be connected to the second channel section 220, at the far end of which there is a steam input hole 175, and on the other hand it is connected to the third channel section 230, at the far end of which a mixing chamber 160 is located. Thus, in In the illustrated embodiments, the channel arrangement 140 is T-shaped, and the seal 130 is correspondingly T-shaped.

In FIG. 4 shows the seal 130 of FIG. in more detail. 3A.

From the above description, it is clear that the various channel sections 210, 220, 230 may be subject to a variety of different conditions during operation of the mixing device 100. Consequently, the respective sealing areas of these channel sections may have their own sealing requirements or specifications. The seal areas may be combined into a single seal, such as an overlap seal, as illustrated. The technical characteristics of the respective seal areas can be easily optimized, for example by locally varying the thickness of the seal. By combining different sealing areas into one seal, there is no risk of leakage when transitioning between different areas.

As explained above, air is drawn through the air intake passage at the end 235 of the third passage portion 230 so that a mixture of milk, steam and air is supplied to the mixing chamber 160. The purpose of the mixing chamber is to release large bubbles and retain only small air bubbles in the mixture. The mixture of air, milk and steam forms a fluid that enters the mixing chamber.

The frothing process involves dividing the bulk air stream into smaller and smaller bubbles until the bubbles are encapsulated in a fluid, then forming a loose mixture of air and milk. Basically, the longer the stream of steam, air and milk has to break down the air, the silkier the foam becomes.

Without a barrier, some large bubbles and bulk air will leak out. However, these bubbles are not stabilized by the fluid and proteins inside the milk, so they float on top of the hot milk and explode very quickly. Thus, they do not contribute to the creation of silky milk foam.

The speed of liquid (milk, steam and air) entering the mixing chamber is important to the quality of the foam. The air enters at the end 235 of the third channel portion 230, and there is an opening leading to the outside air, for example, with a minimum opening size such as formed by a gap of 1.5 mm. The distance between the milk venturi and the air gap and the distance between the air gap and the mixing chamber are parameters for setting the milk frothing characteristics.

Said mixing device is known to the extent that it is described above, and FIG. 2-6 are actually taken from WO 2019/129599 and WO 2019/1029515.

The present invention relates to control of the degree of foaming, i.e. the ratio of foam to milk in the liquid supplied by the outlet 122, and, in particular, in a manner that can be controlled by the user.

In FIG. 5 shows a mixing device according to the invention in a first operating mode. FIG. 5 is a view looking into outlet 122 and thus into mixing chamber 160.

The mixing device includes a barrier element 500 at the outlet of the mixing chamber 160, particularly at the connection between the mixing chamber 160 and the outlet 122.

The barrier element 500 prevents the mixed fluid from leaving the mixing chamber and thereby affects the mixing function and thereby affects the foaming characteristics of the mixing chamber.

The barrier element creates back pressure and thereby changes the flow characteristics and also shifts the balance of ingredients.

In the example shown, the barrier element 500 includes a circular projection extending around the inlet from the mixing chamber 160 to the outlet 122. The circular projection, for example, has different projection heights at different angular positions.

In the example shown in FIG. 5, the barrier element 500 has a 180-degree portion 500a with a larger projection height and a 180-degree portion 500b with a smaller projection height. The "height" of the projection is the amount that the projection extends radially inward from the inner surface of the outlet 122.

The diameter of the outlet pipe is, for example, approximately 20 mm, and the difference in the height of the protrusion can, for example, be in the range of 1 mm to 3 mm.

In this example, the major projection height is, for example, 2 mm, and the lower projection height is zero. This will become clearer with reference to FIG. 7.

In the configuration shown in FIG. 5, a portion 500a with a larger protrusion height is located at the bottom of the outlet pipe. The protrusion in this configuration initiates the foaming function.

In FIG. 6 shows the mixing device of FIG. 5 in section. It shows a protrusion portion 500a that forms a barrier preventing flow from the mixing chamber 160 to the outlet 122 until an elevated liquid level is reached in the mixing chamber.

In FIG. 7 shows an example design of a projection 500. In this example, the projection is a circular projection having a ring 510 with a first projection portion 500a having a projection height h1 and a second projection portion 500b having a projection height of zero. The ring 510 provides structural rigidity and does not affect flow since (when the second protrusion portion 500b is located at the bottom of the outlet 122) the liquid level does not reach the ring 510; instead, fluid flow passes through gap 512 (formed between ring 510 and outlet 122). In alternative embodiments, protrusion 500 may include only a first protrusion portion 500a that can rotate between a position near the bottom of outlet 122 (as shown in FIG. 7) or a position near the top of outlet 122 (not shown). Of course, other projection designs are also possible.

In FIG. 8 shows a mixing device with a second protrusion portion 500b at the bottom. This second protrusion portion has zero height, as explained with reference to FIG. 7.

Thus, in FIG. 5 shows the barrier element in a first static position, and FIG. 8 shows the barrier element in a second static position. The positions are "static" in the sense that the barrier element does not move during mixing and remains in its current position corresponding to the selected foaming characteristics.

The second static position may correspond to a reduced amount of foam (or foamed material) or, in fact, to only hot milk without foaming. Now the protrusion does not present a barrier to the flow from the mixing chamber to the outlet pipe. The fluid level does not reach ring 510 as explained above.

In FIG. 9 shows the mixing device of FIG. 8 in section. Instead, there may be some support for the underside of the ring.

Thus, simply adjusting the rotation of the protrusion between at least the first and second positions is used to provide foam control. It is simple and intuitive for the user.

In this example, the protrusion is a circular protrusion having a set of exactly two discrete protrusion heights, one of which is zero. However, there may be two or more different non-zero projection heights. There may not be a zero projection height setting. There may also be a continuously varying height of the protrusion. This allows you to more accurately select the required foaming.

The barrier element 500 affects the liquid level in the mixing chamber and the time the mixture remains in the mixing chamber before exiting through the mixing chamber outlet. This thus affects the performance of the mixing device. The mixing chamber functions as a foaming bath in which milk, steam and air are foamed as explained above. The barrier element forms an adjustable housing wall that defines the mixing chamber and thus defines the enclosed volume of the mixing chamber.

The barrier element (when configured with a non-zero height) may prevent the mixing chamber from completely emptying. However, a recess or drain channel (not shown) may be provided at the intended low point to function as a drain. It is not so large as to interfere with the function of the barrier element since there is dynamic flow in the mixing chamber, but it allows the mixing chamber to be emptied at the end of use of the mixing device when the circulating flow in the mixing chamber ceases. Thus, the barrier element does not have to be a continuous element.

In FIG. 10 shows the mixing device of FIG. 5-9 to show one example of how adjustment between modes of operation can be made. In the illustrated example, the protrusion is rotated by an outer control ring 600 about the outlet 122. In alternative embodiments, the barrier element 500 may be provided with a handle that can be operated by a user to rotate the barrier element 500. In an alternative embodiment, the barrier element 500 may be rotated by means of a gear transfers.

The present invention has been described in connection with one particular two-piece mixing device design. However, the present invention can be more generally applied to any milk frothing device having a mixing chamber in which steam, milk and air are mixed. The invention includes providing an adjustable barrier element at the outlet of a mixing chamber to control foam formation.

The circular ring is just one possible example. For example, the barrier element may be implemented as an insert or a set of inserts with different radial heights, and the user can select which insert to use depending on the foaming characteristics he desires. Thus, the selection of one from a set of possible barrier elements is intended to be included within the control scope of the barrier element.

The barrier element can be adjusted by sliding, for example vertically, instead of rotating. The barrier element can be adjusted manually or by motorized means. Thus, many methods of implementing an adjustable barrier element at the outlet of the mixing chamber and/or at the inlet of the outlet pipe will be obvious to those skilled in the art.

Other variations to the disclosed embodiments may be understood and made by those skilled in the art in practicing the claimed invention by studying the drawings, disclosure of the present invention, and the appended claims. In claims, the word “comprising” does not exclude the presence of other elements or steps, and singular grammatical indicators do not exclude plurality. The mere fact that certain measures are set out in different dependent claims does not mean that a combination of these measures cannot be used to obtain an advantage. No reference numerals in the claims should be construed as limiting the scope of the invention.

Claims (31)

1. Mixing device containing: a first hole (150) for receiving milk; a second hole (170) for receiving steam; air intake duct for receiving air and a mixing chamber (160) for mixing milk, steam and air to create foamed milk; wherein the mixing device also includes a barrier element (500) at the outlet of the mixing chamber (160), the barrier element being adjustable between at least the first and second positions to set different degrees of foaming. 2. The mixing device of claim 1, further comprising an outlet (122) downstream of the mixing chamber, the barrier element being in a path between the mixing chamber and the outlet. 3. The mixing device according to claim 2, wherein the barrier element (500) includes a protrusion extending along the outlet of the mixing chamber or the entrance to the outlet pipe, and the barrier element is adjustable by rotating the protrusion. 4. The mixing device according to claim 3, wherein the projection is a circular projection. 5. The mixing device according to claim 3 or 4, wherein the projection has different projection heights at different angular positions. 6. Mixing device according to any one of paragraphs. 3-5, wherein the projection has a first projection height and a second, different projection height in diametrically opposed positions (500a, 500b). 7. Mixing device according to any one of paragraphs. 3-6, wherein the protrusion has at least three discrete protrusion heights at different angular positions around the protrusion. 8. Mixing device according to any one of paragraphs. 3-5, in which the protrusion has a continuously varying protrusion height. 9. Mixing device according to any one of paragraphs. 1-8, wherein the barrier element includes a recess at the lowest point for each of a set of operating angular positions. 10. Mixing device according to any one of paragraphs. 1-9, comprising a channel arrangement (140) between the first and second openings and the mixing chamber. 11. Mixing device according to claim 10, in which the channel arrangement contains: a first channel portion (210) connected between the first hole (150) and the foaming section (230); a second channel portion (220) connected between the second hole (170) and the foaming section (230), the foaming section being connected to the mixing chamber (160); And air intake duct to the foaming section. 12. Mixing device according to claim 10 or 11, containing: a first container (110), the first container comprising a channel arrangement; a second container (120), the second container being configured to receive the first container; And a seal (130) located between the first container and the second container. 13. The mixing device according to claim 12, wherein the first container (110) includes a container extension (145), wherein a channel arrangement is formed between the container extension and the seal (130). 14. Mixing device according to claim 12 or 13, wherein the seal (130) comprises a sealing seal. 15. A coffee maker comprising: device for producing liquid coffee extract; mixing device according to any preceding claim and dispensing device configured to dispense: liquid coffee from a device for obtaining liquid coffee extract and frothed milk from the mixing device.