# US 2014/0197554 A1 · Device for foaming milk, beverage maker comprising said device, and method for foaming milk

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- Number: US 2014/0197554 A1
- Document ID: US20140197554A1
- Status: Published application
- Kind: A1
- Application number: 14/118,806
- Filed: 2012-05-21
- Published: 2014-07-17
- Earliest claimed: 2011-05-20
- Assignees: WMF Wurttembergische Metallwarenfabrik AG
- Inventors: Torsten Bönsch; Sander Dollner; Johannes Bais; Marcus Ludwig
- Web page: https://patentgrep.com/patent/US20140197554A1

## CPC

- B01F 23/235: for making foam
- A23C 9/00: Milk preparations; Milk powder or milk powder preparations (mixtures of whey with milk products or milk components A23C21/06; preservation of milk or milk preparations A23B11/10)
- A47J 31/4485: {Nozzles dispensing heated and foamed milk, i.e. milk is sucked from a milk container, heated and foamed inside the device, and subsequently dispensed from the nozzle}
- B01F 23/23: by introducing gases into liquid media, e.g. for producing aerated liquids
- B01F: MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING (mixing paints B44D3/06)
- A23C: DAIRY PRODUCTS, e.g. MILK, BUTTER OR CHEESE; MILK OR CHEESE SUBSTITUTES; PREPARATION THEREOF (preservation thereof A23B11/00)
- A47J: KITCHEN EQUIPMENT; COFFEE MILLS; SPICE MILLS; APPARATUS FOR MAKING BEVERAGES

## Abstract

The present invention relates to a device for frothing up a liquid, in particular cold and/or unheated milk, having a liquid supply line for supplying the liquid, an air supply line which opens into the liquid supply line for supplying air into the liquid, a discharge line which is configured downstream of the opening of the air supply line into the liquid supply line for discharging the mixture of liquid and air, a first conveying unit, in particular a pump, which is provided for conveying the liquid through the liquid supply line and/or the mixture through the discharge line and a mixing unit which is provided downstream of the opening in the discharge line, the mixing unit including at least one narrow place or being configured as narrow place of the discharge line.

## Claims

### Claim 1

A device for frothing up a liquid, in particular cold and/or unheated milk, which is configured for active introduction of air via an air supply line into the liquid, said device comprising:
a liquid supply line for supplying the liquid,
the air supply line which opens into the liquid supply line for supplying the air into the liquid,
a discharge line which is configured downstream of the opening of the air supply line into the liquid supply line for discharging the mixture of liquid and air,
a first conveying unit, in particular a pump, which is provided for conveying the liquid through the liquid supply line and/or the mixture through the discharge line and
a mixing unit which is provided downstream of the opening in the discharge line, the mixing unit including at least one narrow place or being configured as narrow place(s) of the discharge line.

### Claim 2 (depends on 1)

The device according to claim 1, wherein, for active introduction of the air, a further, second conveying unit is provided for conveying the air, the device for frothing up the liquid including in this case precisely two conveying units, and/or in that, for active introduction of the air, a compressed air container which is connected at the upstream end of the air supply line, which is therefore orientated away from the opening, to said air supply line, with which compressed air container, compressed air can be supplied to the air supply line, the device for frothing up the liquid including, in this case, precisely one conveying unit.

### Claim 3 (depends on 1)

The device according to claim 1, wherein the air supply line opens by its downstream end into the liquid supply line upstream of the first conveying unit, or in that the air supply line opens by its downstream end into the liquid supply line downstream of the first conveying unit, or in that the air supply line opens by its downstream end into the first conveying unit.

### Claim 4 (depends on 1)

The device according to claim 1, wherein the mixing unit includes at least two narrow places which are integrated in succession in the discharge line.

### Claim 5 (depends on 1)

The device according to claim 1, wherein at least one of the narrow places is/are configured or provided as follows:
as a throttle- or needle valve,
as a nozzle,
as a clamp, in particular as a hose clamp, for a flexible discharge line portion, in particular for a discharge line configured as flexible hose,
in the form of a discharge line configured as a variable clamp or a variable hose clamp,
as a diaphragm, in particular as cross-sectional-tapering perforated diaphragm with a perforation diameter which can be varied or is adjusted to a fixed value or as an annular gap diaphragm with a gap width which can be varied or is adjusted to a fixed value, or
as a longitudinally extended annular gap which widens constantly about a cone in downstream direction, and/or
in that at least one of the narrow places is/are configured either with a variable free cross-sectional area F, Fa or Fb or is/are configured with a predetermined, free cross-sectional area F, Fa or Fb which is adjusted in a fixed manner.

### Claim 6 (depends on 1)

The device according to claim 1, wherein a portion of the discharge line, downstream of the mixing unit, is configured as a settling stretch with which the turbulent proportion of the flowing mixture of liquid and air can be reduced such that the laminar proportion of this flowing mixture can be increased, the portion having a constant line cross-section on a predefined length in the flow direction.

### Claim 7 (depends on 1)

The device according to claim 1, wherein one of the three subsequently listed features is provided for the first conveying unit:
the first conveying unit is disposed upstream of the opening, in particular integrated in the liquid supply line,
the first conveying unit is disposed in the region of the opening, in particular integrated in the liquid supply line and/or in the discharge line,
the first conveying unit is disposed downstream of the opening, in particular integrated in the discharge line; and
in that the mixing unit, is configured either as part of the first conveying unit and/or is disposed downstream of the first conveying unit.

### Claim 8 (depends on 1)

The device according to claim 1, wherein the air supply line, the liquid supply line or the discharge line has a mixing region into which a steam supply line opens for supplying steam or a mixture of air and steam to the liquid or to the mixture of liquid and air.

### Claim 9 (depends on 8)

The device according to claim 8, wherein the mixing region is disposed upstream or downstream of the mixing unit or in the mixing unit and/or downstream of the first conveying unit, and/or in that active air can be introduced into the steam supply line, in order to produce the mixture of air and steam, the mixture being produced by a further, third conveying unit, in particular a pump, for conveying air, which is disposed in a further air supply line which opens into the steam supply line, and/or by a further compressed air container which is connected at the end of the further supply line, which is orientated away from the opening of such a further air supply line into the steam supply line, to said further air supply line.

### Claim 10 (depends on 8)

The device according to claim 8, wherein the mixing region is configured as an opening of a line portion into another line portion, in particular as T-shaped line part, or in that the mixing region is configured as a Venturi nozzle, the steam supply line leading into the mixing region forming the inlet of the Venturi nozzle, the portion of the discharge line leading out of the mixing region in the downstream direction forming the outlet of the Venturi nozzle and the portion of the discharge line leading into the mixing region from the upstream direction forming the removal pipe of the Venturi nozzle.

### Claim 11 (depends on 1)

The device according to claim 1, comprising a bypass line which branches off from the liquid supply line upstream of the first conveying unit and opens into the discharge line either downstream of the mixing unit or opens upstream of the mixing unit but downstream of the first conveying unit into the liquid supply line and/or the discharge line, the branching being configured preferably as a multiway switching unit with which the liquid to be supplied can be guided to the discharge line optionally either via the bypass line or via the first conveying unit.

### Claim 12 (depends on 1)

A drink preparation apparatus, said apparatus including a device for frothing up a liquid according to claim 1, wherein the downstream end of the discharge line of the device is configured as separate dispensing line of a dispensing head.

### Claim 13 (depends on 1)

A method for frothing up a liquid, in particular cold and/or unheated milk, wherein the frothing up is implemented with a device according to claim 1.

### Claim 14 (depends on 4)

The device according to claim 4, wherein a ratio Fa/Fb of the free cross-sectional area Fa of a first narrow place situated upstream and of the free cross-sectional area Fb of a second narrow place situated downstream is in the range between 1/1.05 and 1/16.