Milk foamer with device for forming bubbles

The present invention relates to a coffee maker with steam generator and milk foaming which a downstream of a steam outlet pipe arranged suction chamber, an opening into the suction milk supply line, a downstream of the suction nozzles arranged portion and at least one outlet opening comprises.

Simple devices for generating milk foam have a connected to the steam generator of the coffee making pus steam nozzle, at its outlet there are several orifices. This frother is dipped for producing the milk foam under the liquid level of a filled milk jar and the milk container is moved in an up and down movement around the steam nozzle around to achieve the desired foaming of the milk. The handling of such frother requires some experience to give a spraying of milk can still hardly be avoided. A disadvantage of such a frother is to say that only small quantities of milk in accordance with small containers can be foamed.

More simple devices comprise a steam generator connected to the steam pipe, to the outlet of which a nozzle arrangement is provided with channels for sucking air and milk. This nozzle arrangement is again dipped to produce the milk foam under the liquid level of filled milk jar. If the nozzle assembly is perfused with steam, air and milk are sucked through the corresponding channels in the die assembly and produces the desired milk foam. Although these devices may facilitate handling compared to a simple steam pipe, but the drawbacks essentially remain.

From EP 195 750 B1, a milk foaming device is known which is provided with a supply conduit for milk, which ends in an external reservoir. The apparatus further has a suction chamber and a Verwirbelungsanordnung which swirls the inflowing from the suction chamber steam-air milk mixture to a baffle, thereby achieving the foaming action. Through an opening in the Verwirbelungsanordnung the resulting foamed milk can flow directly into a drinking vessel. Despite these relatively expensive construction of the milk foam not always know on the desired properties.

From EP 858 757 B1 another milk foaming device is known in which is created in the vacuum chamber, a steam-air milk mixture flowing from there into a settling section, where it is compressed and calmed down, so that it emerges as milk froth from the calming section , must be made relatively long to achieve a good foam formation, the calming section. Also, an air-milk mixture must be formed in a pre-mixing chamber first, which flows from there into the vacuum chamber.

Another milk foaming for a coffee maker with steam generator, DE 197 05 633 C2, in which in a vacuum chamber, a milk-steam mixture is formed that flows through a subsequent to the vacuum chamber expansion path into a Verwirbelungsanordnung. In the Verwirbelungsanordnung horizontal guide vanes are arranged, which are arranged such that is rotated by passing through them steam-milk mixture in rotation, air is sucked in and entrained. This einsteht a milk foam with a high air component, whereby the desired consistency is not always achievable.

The well-known in the art Milchschäumvorrichtungen for coffee machines are either hard to use or hard to adjust in spite of elaborate structures without ensuring the desired milk foam consistency. Even cleaning the Milchschäumvorrichtungen is often fraught with problems, including elaborate constructions.

The present invention is therefore the object of providing a coffee maker with steam generator and milk foaming, wherein the milk foaming device is based on a relatively simple construction and nevertheless permits the best possible foam generation and an easy cleaning.

This object is achieved for a generic coffee maker with steam generator and milk foaming in that between the nozzle portion and the at least one outlet opening of the milk foaming a sieve is arranged.

The inventive development of the milk foaming a coffee pus foaming of sucked milk without any prior addition of air or a swirling the milk-steam mixture is achieved with air. In this case, ie, causes neither in the suction chamber in the nozzle, a suction or an admixture of air in the milk foaming device before the screen. As a screen, each beam splitter is usable with a lattice structure, for example, mechanically or manufactured in an etching process perforated discs, the sieve can also be formed by a plurality of spaced layers of a beam splitter with a lattice structure.

To produce a fine and uniform milk froth the milk foaming device may comprise a foaming chamber, which is arranged between the screen and the at least one outlet opening. In this case, preferably, the milk foaming device comprising a discharge section in which the foaming chamber and the at least one outlet opening are formed. As a result, the necessary training for the milk foaming number of components can be reduced. Next is possible through the outlet portion finer adjustment between the foaming chamber and the outlet opening.

A favorable embodiment provides that the milk foaming device has an expansion chamber disposed between the nozzle portion and the sieve. This expansion chamber allows for better, large-scale distribution of exiting the nozzle portion steam-milk mixture before striking the screen, thus ensuring an optimal foam production. By means of the expansion chamber is further the distance between the nozzle and the well screen adjustable.

An advantageous embodiment provides that an expansion portion is provided in which the expansion chamber is formed, wherein the screen downstream of the expansion chamber to the expansion portion is arranged. The expansion portion can be easily an expansion chamber formed which is limited by the formed on the extension portion sieve. So can also be dispensed with for the arrangement of the screen with additional components. Also can be aligned in this way, the screen in relation to the expansion chamber well. For secure attachment of the screen, the screen can be fixed to the extension portion, preferably be welded. In this case, the expansion portion can preferably be made of plastic, whereby a very simple mounting possibility is by welding of the wire with the end edge of the expansion portion. Thus a particularly favorable manufacture of the expansion portion with an integrated screen is possible.

An advantageous variant provides that the sieve is removably disposed relative to the nozzle portion. This allows an easy cleaning of the sieve and the entire nozzle.

In order to improve the cleaning of the screen and to facilitate cleaning of the frothing chamber, the screen may also be removably arranged relative to the foaming chamber.

A further embodiment provides that the screen is formed from one or more spaced-apart layers of a fine mesh cloth. A finely woven fabric is a simple form of the necessary for the Milchschäumung screen, which is produced in many different ways, from many manufacturers is obtainable and can be easily edited. It can be made of temperature-resistant plastic for an inexpensive solution the fine-meshed fabric. Further, the fine-meshed fabric be produced in a stable, robust embodiment of stainless steel, so the screen can withstand stressful operating conditions well.

In one embodiment, it is provided that the fine-meshed fabric, a mesh width / wire thickness ratio of 75/50 to 140/110, preferably at about 100/65. Tests have shown that a wire thickness of 50 to 110 .mu.m, preferably about 65 microns, particularly well suited is the incident milk-steam mixture to divide. Here, the impinging fluid jet is literally cut so that only a small portion in the upstream portion, typically the expansion chamber, is reflected. Moreover, in such a thin thread thicknesses also remains more space for the openings in the screen and thus the opening for the passage of the milk-steam mixture. Parallel to the thread thickness is for the screen has a mesh manner, and a hole diameter, 75-140 microns, preferably about 100 microns, provided. Due to the many opening edges of such small openings are formed corresponding to many Verwirbelungskanten that are responsible for the desired foaming of the milk-steam mixture.

In order to enable a good steam flow in the milk foaming of the coffee making pus, the vapor outlet pipe and the nozzle portion may be disposed coaxially to one another. By this arrangement, the steam in the suction chamber with minimum loss to the nozzle can be directed.

Advantageously, may comprise at least an upper and lower nozzle portion of differing diameters, the nozzle portion, wherein preferably the adjacent to the suction chamber upper nozzle portion having the smallest diameter. In this way a certain expansion of the steam-milk beam is made possible already in the nozzle. Through these nozzles form the usual manner can then expansion chamber be made shorter and so the whole milk foaming be made more compact.

A preferred embodiment provides that the ratio of the diameter of the nozzle portion with the smallest diameter to the internal diameter of the steam outlet pipe from 1.5 to 3, preferably about 2 amounts. Through the enlarged diameter ratio of the whole emerging from the vapor outlet pipe dry steam can be well guided through the nozzle inlet into the nozzle without requiring a guide funnel is necessary. The increase in volume of the vapor stream in the suction chamber by the aspirated milk can be easily incorporated.

Another embodiment provides that the ratio of the internal diameter of the steam outlet pipe to the inside diameter of the milk supply 0.5 to 1, preferably about 0.75, is. This diameter ratio allows a suitable for the milk frothing ratio of steam to milk.

In order to realize good foaming conditions by a large-surface impingement of the milk-steam mixture on the sieve, the ratio of the distance between the nozzle portion and the sieve to the diameter of the nozzle portion with the smallest diameter preferably 4 to 6, 4.5 to 5, respectively,.

For milk foaming conventional coffee maker, the smallest diameter of the nozzle portion may 2.5 to 3.5 mm, preferably about 3 mm. This nozzle size the milk foaming a serving steamed milk is appropriate to provide in a sufficiently short for a normal user time, without requiring a larger sized steam generators. In order to ensure a sufficient supply of steam, may the internal diameter of the steam outlet pipe 1 to 2 mm, preferably about 1.5 mm, respectively. With such internal diameter the vapor outlet pipe is adapted to the steam generators used in conventional coffee formulators.

Conveniently, the internal diameter of the milk inlet line 1.5 to 2.5 mm, preferably about 2 mm. This inner diameter allows for optimal milk supply to suction the milk foaming with good foaming and heating of the milk to drinking temperature through the milk foaming.

For good foaming conditions, the nozzle portion and the sieve can in a distance of 10 to 18 mm, preferably 12 to 16 mm, may be arranged.

For simple embodiment of the connection to the steam generator, the milk foaming device may include a steam connector for accommodating the steam connector pipe, wherein between the steam connector and the steam outlet pipe, at least one seal, preferably at least one O-ring, is provided. The integration of a seal between the steam connection and steam outlet, preferably in a circumferential groove of the steam outlet pipe is, ensures reliable sealing function of the steam connection. This is particularly in view of the risk of burns careless user of coffee formulator of great importance.

An advantageous embodiment provides that the suction chamber has a quasi-elliptical shape, wherein the vapor outlet pipe centrally and the milk inlet open into the suction chamber side, and the nozzle portion is disposed centrally on the bottom of the suction chamber. The quasi-elliptical shape of the suction chamber forms, together with the arrangement of the leads and outlets an effective configuration for a safe and uniform supply of the milk and the supply of the milk-steam mixture to the nozzle. It will be recognized as a quasi-elliptical shape a stylized elliptical shape with straight sections. The underlying in the flow direction of the suction chamber floor is flattened, the majority of land occupied by the nozzle opening. a frustoconical section joins to the floor, which merges into a middle annular portion with a constant diameter, the ring portion at the same time forms the largest diameter of the quasi-elliptical suction chamber, which is arranged in the region of this annular portion, the milk supply. Above the ring portion a truncated conical portion is disposed at a first frustoconical portion opposite slope again. This second frusto-conical region terminating centrally in a flattened area, in which the opening of the steam inlet is arranged.

For a reliable supply of steam into the suction chamber, the steam outlet pipe may protrude into the suction chamber, preferably downstream protrude through the milk supply. By such a protrusion of the flattened upper, provided with the opening of the steam inlet area into the suction chamber, the vapor outlet pipe introduced with only a slight decrease in volume of the suction chamber closer to the nozzle and so that a better inflow behavior of the steam or of the milk-steam mixture, in which reaches nozzle. With the projection of the steam outlet pipe through the milk supply a very compact design is achieved despite a still relatively large volume of the suction chamber. This undercut allows extremely close arrangement of the steam outlet pipe to the nozzle and so a virtually lossless inflow behavior of the steam, and the milk-steam mixture into the nozzle.

The invention further relates to a milk foaming device for use with a coffee maker according to any one of claims 1 to 24, in which an upstream of a steam outlet pipe are arranged suction chamber, an opening into the suction chamber milk intake conduit, a downstream of the suction chamber arranged nozzle portion and at least one outlet opening, wherein between the nozzle portion of the at least one outlet opening is arranged a sieve. This milk foaming allows a fine-pored foaming of sucked milk without an admixture of additional air or swirling the milk-steam mixture before the sieve, ie. In the suction chamber or in the nozzle This produces a particularly fine-pored milk foam which long retains its expanded structure without collapsing.

In the following, embodiments of the present invention with reference to the drawings will be explained in more detail. Show it:<dl id="dl0001"><dt>Fig. 1</dt><dd>a side sectional view through a milk foaming a coffee pus invention,</dd><dt>FIG. 2</dt><dd>a sectional side view of the Schäumaufsatzes from FIG. 1,</dd><dt>Fig. 3a</dt><dd>showed a bottom view of the spout portion of FIG. 1,</dd><dt>FIG. 3b</dt><dd>shows a side sectional view of the spout portion of FIG. 1,</dd><dt>FIG. 4a</dt><dd>shows a bottom view of another embodiment of the outlet portion, and</dd><dt>Fig. 4b</dt><dd>shows a side sectional view of the spout portion of FIG. 4a.</dd></dl>

In Fig. 1 the milk foaming device 1 a coffee formulator according to the invention. The coffee maker has otherwise in the art well-known features such as water tank, water heater or boiler, a brewer, a steam generator, etc .. The milk foaming 1 illustrated is for foaming and simultaneous heating of milk. For this purpose, the milk foaming device 1 a nozzle portion 2 and a Schäumaufsatz 3.

The nozzle part 2 includes a vapor port 4, a milk connection 5, a suction chamber 6 and a nozzle portion 7 of the steam connection 4 serves for receiving the vapor outlet pipe 8 with the steam channel 9. In a groove of the steam outlet pipe 8, an O-ring 10 is arranged, which the gap between the vapor outlet pipe 8 and the steam connection 4 seals against the environment. The outlet opening 11 of the steam channel 9 projects into the suction chamber. 6 The milk terminal 5 includes a milk channel 12, which opens into the suction chamber 6 laterally. The milk terminal 5 further includes a hose connector 13 to which a flexible hose (not shown) is pushed, with which the milk connection 5 with a milk-filled container is connected (not shown).

At the bottom of the suction chamber 6, which is shaped in the form of two truncated cones and, arranged between these truncated cones ring portion, wherein the end faces of the truncated cones is contiguous with the larger diameter at the middle ring and the outlet port 11 of the vapor outlet pipe 8 from the top face of the suction chamber 6 projecting into the suction chamber 6, is adjacent to the nozzle portion 7 with the nozzle opening fourteenth The nozzle portion 7 includes an upper nozzle portion 15 and a lower nozzle portion 16, wherein the diameter of the upper nozzle portion 15 is smaller than the diameter of the lower nozzle portion 16 is. The nozzle portion 7 further includes an outer terminal 17 in the form of a paragraph in the cylindrical shell on which the Schäumaufsatz 3 can be pushed.

The Schäumaufsatz 3 consists of an expansion portion 18 and an outlet section 19. In the extension portion 18, the expansion chamber 20 is formed which extends between the nozzle portion 7 of the nozzle part 2 and the end face disposed on the expansion portion sieve 21st The upper part of the expansion portion 18 is pushed onto the connection 17, wherein the nozzle portion 7 projects slightly into the expansion chamber twentieth The division of the expansion portion 18 in an upper and lower part by means of the stage 25 can be clearly seen in Fig. 2. The lower part of the expansion portion 18 is completely surrounded by the outlet section 19, thus resulting in a double wall in the area of ​​expansion chamber 20th The outlet section 19 extends below the screen 21 on up to the outlet openings 22. Between the outlet openings 22 and the wire 21, the foaming chamber 23 is through the outlet section 19 is formed. Between the outlet openings 22 a bulge 24 is formed in the bottom of the outlet portion 19th

In the bottom view of the outlet section 19 shown in FIG. 3 can be seen clearly 22 the circularly arranged outlet openings. Six outlet openings 22 are grouped here in a uniform distance around the inwardly bulging 24th

In FIGS. 4a and 4b, another embodiment of an outlet portion 19 is shown for use with a milk foaming 1st Here, the bottom of the outlet portion 19 is flat. Again, in turn, six discharge openings 22 at an equal distance to each other and to the center of the outlet portion 19 is arranged.

Hereinafter, the effect and operation of the above-described milk foaming 1 is explained in detail.

The milk foaming 1 is connected to the vapor outlet pipe 8 to the steam generator of the coffee making pus. About the vapor channel 9 flows dry water vapor in the suction chamber 6, which is sealed by the O-ring 10 between the vapor outlet pipe 8 and the steam connection 4 from the environment. Taking advantage of the Venturi principle, the negative pressure is generated by means of the air flowing into the suction tube vapor which draws milk through the channel 12 of the milk terminal 5 milk from a container, not shown. The air flowing into the suction chamber 6 milk mixes here with the water vapor. Here, the milk is heated and, together with the dry steam, a milk-steam mixture flowing from the suction chamber 6 into the nozzle portion. 7 The laterally flowing into the suction chamber 6 Milk is 9 predetermined flow direction, here in vertical direction entrained by the steam in the steam through the channel. The milk-steam mixture flows through the upper nozzle portion 15 and the subsequent lower nozzle section 16, wherein the beam passes through the slightly larger diameter already can widen a bit in the lower nozzle heading 16. In the subsequent expansion chamber 20, the beam emerging from the nozzle section 7 milk-steam mixture expands further, so it as large as possible strikes the screen 21 at the end of the expansion chamber 20th The milk-steam mixture meets with relatively high kinetic energy onto the screen 21 through the screen 21 of the liquid jet is often divided. Here, the upward reflected in the expansion chamber 20 portion is extremely low and is entrained by the inflowing liquid jet immediately toward the screen 21st By exiting from the mesh of the screen 21 plurality of partial beams intensive foaming of the milk-steam mixture is achieved in the foaming 23rd The forming foam can settle down in the foaming chamber 23 and discharged to the outlet openings 22 as a closed and relatively uniform foam jet.

Depending on the configuration of the bottom portion of the outlet section 19, as a flat bottom or with a bulge 24 which can discharge conditions in the froth forming and striking the bottom of the outlet portion 19 foam vary, which allows the foam properties of the expiring milk foam Set.

By far projecting into the suction chamber 6 outlet 11 of the vapor channel 9 results in only a small distance from the nozzle opening 14, whereby the steam can easily lead to the nozzle opening 14 despite the influence of the lateral inflow and sucked in by the jet of steam milk. So can be dispensed with a funnel-shaped opening of the nozzle portion. 7 By undercut the milk channel 12, ie, the projection of the outlet opening 11 in the direction of flow towards the milk channel 12, the lead property is further improved, since the side of the milk channel 12 flowing milk can not flow directly into the steam jet.

The milk foaming 1 for a coffee maker according to the invention can easily form a plurality of parts, the nozzle part 2, expansion section 18 and outlet section 19, are made of heat-resistant plastic. In this case, the nozzle member 2 is preferably constructed of a rigid material with a view to forming in the suction chamber 6 under pressure while the expansion portion 18 and the outlet portion 19 of the Schäumaufsatzes 3 also made of an elastic or part-elasticated material can be manufactured. In this case, the screen can be 21 depending on the material in a relatively simple manner by attaching weld on the face of the expansion portion 18th

To clean the milk foaming device 1 can after each Milchschäumvorgang equally through the milk connection 5 water are fed into the suction chamber 6 and cause the cleansing of contaminated milk components. For extensive cleaning of the individual components, the nozzle part 2, extension portion 18 with filter 21 and outlet section 19 with outlet openings 22, the parts can be made in the simplest way apart and are then cleaned thoroughly by hand or in a dishwasher.