Milk frother system and operating method

Abstract

A milk frother system includes a gear pump which, at an inlet side is connected at least to a milk feed conduit that, for its part, is connected during operation to a milk vessel that can be filled with milk, for example by way of it projecting into the vessel. The gear pump sucks milk out of the milk vessel via the milk feed conduit. The system also includes a feed conduit for water and/or steam to the gear pump, for example in order to rinse this after use or also, by way of the feed of steam, to heat the delivered milk. The milk frother system is configured, under predefined conditions and before delivery of milk, to deliver water and/or steam to the gear pump via the feed conduit, in order to wet the gear pump.

Claims

1. A milk frother system, comprising a gear pump which at the inlet side is connected at least to a milk feed conduit which is connectable to a milk vessel that is filled with milk, by which means milk can be sucked out of the milk vessel by the gear pump, and further comprising a feed conduit for water and/or steam to the gear pump, wherein the milk frother system is configured to deliver, only under predefined conditions, before delivery of milk by the gear pump, and as a reaction to a user's activating a delivery of milk, water and/or steam to the gear pump via the feed conduit, in order to wet the gear pump, and wherein the predefined conditions comprise at least one of: the system has been switched on after a last operation of the gear pump; the system has been woken from a standby mode or sleep mode; a milk frother appliance, which comprises the gear pump, has been removed from a base unit and placed on the base unit again; more than a predefined time has elapsed since a last operation of the gear pump.

2. The milk frother system according to claim 1, wherein the milk vessel is arranged further to the bottom than the gear pump.

3. The milk frother system according to claim 1, comprising a control unit which is programmed, before the delivery of milk by the gear pump, to deliver the water and/or steam to the gear pump only under the predefined conditions.

4. The milk frother system according to claim 1, wherein gearwheels of the gear pump are coated with a fluorine-containing polymer or consist of a fluorine-containing polymer.

5. The milk frother system according to claim 1, further comprising a device for feeding air to an inlet side of the gear pump.

6. The milk frother system according to claim 1, further comprising the milk frother appliance, which comprises the gear pump, and the base unit having a water pump and a water heater, wherein the water and/or the steam can be delivered by the base unit for the wetting of the gear pump and can be delivered into the feed conduit via an interface.

7. The milk frother system according to claim 6, wherein the base unit is designed as a coffee machine for preparing coffee from coffee powder, which is present in a portion packaging, and from hot water.

8. The milk frother system according to claim 1, comprising a mixing nozzle that connects onto the gear pump at the outlet side and to which milk, which is delivered by the gear pump, steam and optionally air can be fed.

9. A method for operating a milk frother system, with a gear pump, which is connected at the inlet side at least to a milk feed conduit, which is connectable to a milk vessel, which is filled with milk, and further comprising a feed conduit for water and or steam to the gear pump, according to which method, after activation by a user for a delivery of milk to the gear pump, the gear pump sucks milk out of the milk vessel and delivers the milk further from there, wherein only under predefined conditions, after the activation and before the delivery of milk, water and/or steam is led to the gear pump via the feed conduit, in order to wet the gear pump, and wherein the predefined conditions comprise at least one of: the system has been switched on after the last operation of the gear pump; the system has been woken from a standby mode or sleep mode; a milk frother appliance, which comprises the gear pump, has been removed from a base unit and placed on the base unit again; more than a predefined time has elapsed since the last operation of the gear pump.

10. The method according to claim 9, wherein a liquid volume of the water and/or steam which is delivered under the predefined conditions is between 1 ml and 10 ml.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiment examples of the invention are hereinafter described by way of figures. The same or analogous elements are indicated in the figures by the same reference numerals. There are shown in:

(2) FIG. 1 a view of the appliance for preparing frothed milk (milk frother appliance);

(3) FIG. 2 an exploded representation of the milk frother appliance;

(4) FIG. 3 an exploded representation of the milk frothing unit of the milk frother appliance;

(5) FIG. 4 a view of the milk frothing unit, which is sectioned along a horizontal plane;

(6) FIG. 5 a partial view of the seal of the milk frothing unit with elements of the gear pump,

(7) FIG. 6 a view of the upper base housing part of the milk frothing unit, which is sectioned along a horizontal plane;

(8) FIG. 7 a view of the upper base housing part from below;

(9) FIG. 8 a view of the upper base housing part, which is sectioned along a vertical plane;

(10) FIG. 9 a view of a drinks preparation machine; and

(11) FIG. 10 a schematic view of a milk frother system according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(12) The appliance 1 for preparing frothed milk (milk frother appliance) is represented as a whole in FIG. 1. FIG. 2 shows an exploded representation of its parts. The appliance 1 includes a milk container 3, a milk frothing unit 5 and a cover 6.

(13) The elements of the milk frothing unit 5 are represented in an exploded representation in FIG. 3. A lower base housing part 11 carries an electric motor 13 belonging to the gear pump, as well as an upper base housing part 14. A lateral window 12 is formed in the base housing.

(14) The upper base housing part 14 forms a roughly circularly cylindrical trough, in which gears 17 of a gear pump are arranged. The gearwheels 17 of the gear pump are driven via a shaft 19, which is connected to the electric motor 13. A seal 21 seals the trough to the bottom.

(15) Additionally to the gears, the shaft and the electric motor, the gear pump can also have its own housing, or such can be integrated into the base housing or other parts, for example into a milk frothing unit cover 16. In the represented embodiment example, the milk frothing unit cover 16 is shaped out such that a pump chamber encompassing the gearwheels 17 is formed between the seal 21 and the milk frothing unit cover 16 on account of an arching 15 (also clearly visible in FIG. 12). The dimensioning of the pump chamber is matched in an exactly fitting manner to the outer dimensions of the gearwheels, which, for their part, fit into one another in an exactly fitting manner.

(16) A milk suction tube 18 (not represented in FIG. 3) extends downwards from the plane of the gear pump and projects into the milk container 3 and almost up to the base of this in the assembled condition of the appliance 1.

(17) An activatable valve unit 20 for the air, which gets into the inlet side of the gear pump into the milk frother, is fastened to the base housing 11, 14. Likewise visible in FIG. 3 are a spacer 23 and a motor seal element 24.

(18) A connection shaped part 22 is further present beneath the gear pump. This part seals the window 12 and simultaneously forms a feed-through for connection between conduits of the milk frother, which are fastened to the base housing, and a docking element. The docking element includes a docking element body, which is protected by a docking element housing 26. The docking element body is formed by a base body 25 and a supplementary part 27. Amongst other things, the supplementary part 27 includes a downwardly projecting milk froth outlet 28; and the mentioned mixing nozzle 79 (see FIG. 10) is also arranged in the main body 25 or possibly in the supplementary part.

(19) FIG. 4 shows a view from above, of the milk frothing unit 5, which is sectioned along a plane that lies above the sealing plane defined by the seal 21. The lighter lines in the plan view represent elements running further below, which per se are not visible.

(20) The gear pump is attached above the sealing plane. An upper-side liquid conduit 31 leads to the gear pump. This is connected, on the one hand, to the milk suction tube 18 and, on the other hand, to a hot water and/or steam feed conduit 32, via duckbill valves 42, 42, which are formed by the seal 21 and are also clearly visible in FIG. 5. An air feed conduit 34 is connected to the upper-side liquid conduit, which is to say to the gear pump at the inlet side, likewise via a duckbill valve 43, which is formed by the seal.

(21) Arranged behind the gear pump is a feed-through 36 for the delivered milk which, depending on the selected operating condition, is already frothed, through which feed-through this milk again goes downwards through the sealing plane, where it goes through an outgoing conduit 35 into the docking element and there into the mixing nozzle.

(22) FIGS. 6 to 8 show further views of the upper base housing part 14, which is represented sectioned along a horizontal plane in FIG. 6 and along a vertical plane in FIG. 8 and in a view from below in FIG. 7.

(23) The lower-side conduits are formed by flexible tubes of the connection shaped part 22, which are laid into the corresponding channels of the upper base housing part 14. These, i.e. the channel 51 for the hot water and/or steam feed conduit 32, the channel 52 for the air feed conduit 34 and the channel 53 for the outgoing conduit 35, are particularly clearly visible in the view from below according to FIG. 7.

(24) The seal 21 (FIG. 8) is clamped between the upper base housing part 14 and the milk frothing unit cover (not shown in FIG. 8). The pump chamber of the gear pump including the gearwheels 17 is formed between the milk frothing unit cover and the upper base housing part due to the arching 15 in the milk frothing unit cover (FIG. 3).

(25) FIG. 9 shows a view of the complete drinks preparation machine 100 with the milk frother appliance 1 and a base unit, which is designed as a coffee machine 101, and onto which the milk frother appliance 1 is coupled.

(26) The coffee machine, as is known per se for coffee machines, includes a water container, a water pump and a water heater. A brewing chamber for preparing coffee from heated water by way of extraction from coffee power is moreover present, the coffee powder being provided, for example, in portion capsules, which were previously inserted into the coffee machine before the preparation. As an alternative to a portion capsule system, the coffee machine can also be designed as a so called bean-to-cup coffee machine, which also includes a coffee mill and grinds the coffer powder in a portioned manner and feeds it to the brewing chamber. As yet a further alternative, particularly if the coffee machine is designed as a piston machine, i.e. the brewing chamber is formed between a fixed part and a removable piston, one can yet also envisage the coffee powder being brought into the brewing chamber by the user in the already ground, but loose (non-compacted) condition.

(27) The coffee machine can further include a capture container for spent coffee powder portions (in capsules or in a loose manner, depending on the design of the coffee machine).

(28) A placement platform 103 for placing a drinks vessel is formed on the coffee machine. A coffee outlet 105, through which brewed coffee runs out and gets into the vessel lying therebelow is located above the placement platform 103. This outlet is located below an outlet hood 108, which forms part of the coffee machine housing and at least partly covers the outlet to the front and to the sides. A connection location 110 for the connection of the docking element onto the coffee machine is located in the proximity of the coffee outlet 105 and here below the outlet hood. This connection location includes a steam delivery location for coupling onto the steam connection of the docking element, and a hot water and/or steam delivery location for coupling (via a conduit in the docking element) onto the hot water and/or steam feed conduit 32. The steam delivery location and the hot water and/or steam delivery location, when required, are supplied with steam and hot water respectively from the water heater, wherein a multi-port valve in the inside of the coffee machine can feed heated liquid or steam selectively to the brewing module, to the steam delivery location or to the hot water and/or steam delivery location.

(29) The docking of the milk frother appliance 1 is effected from the side onto the outlet hood 108, and specifically such that the milk frother appliance as a whole is arranged in front of the coffee machine and laterally of the outlet hood 108.

(30) The connection location further preferably includes electrical contacts. These electrical contacts form an interface and, given a coupled-on docking element, create an electrical connection to corresponding electrical connection element contacts, which are connected to electrical leads that lead through the docking element or are formed by these. These electrical leads supply the electrically driven elements of the milk frother appliance, specifically the gear pump, with electricity and control signals as the case may be.

(31) Thereby, it is possible to provide a control of these electrically driven elements in the milk frother appliance (this appliance is then provided with the necessary electronic units and receives control signals from the coffee machine or from an input unit of the milk frother appliance) as well as to accommodate a control of these elements in the base unit itself. In the latter case, it is essentially only currents that drive the electrically driven elements in accordance with the settings of the control that are led through the electrical leads.

(32) In particular, the control of the gear pump is configured such that the speed of the gearwheels 17 can be adjusted, i.e. is selectable. By way of this, the user can control the delivery speed and-according the procedure, which is described in more detail hereafter-as the case may be the preparation of cold frothed milk.

(33) FIG. 10 shows an overview diagram of the milk frother appliance and its coupling onto the base unit (coffee machine 101). Air feeds are indicated at “L” in the figure. The letter D indicates a conduit for steam, K a conduit for the hot drink, R the conduit for the cleaning water or cleaning steam, which is partly formed by the hot water and/or steam feed conduit 32, and S indicates the electricity supply. Steam that is fed into the steam feed conduit D via the steam connection gets into the mixing nozzle 79, for example via a valve.

(34) The activation 195 here is represented as part of an electronics unit 121 (control unit) of the coffee machine 101. The electronics unit 121 is configured, for example, to recognise a capsule by way of a measurement and/or to accept a user input, for example via a suitable operating element with a corresponding button, with a touchscreen and/or the like.

(35) Here, the activation 195 is designed such that it can activate the gear pump 7 as well as the valve unit 20, wherein an operating parameter of the gear pump and/or of the valve unit can be regulated (closed-loop controlled). Activation signals for the valve unit 20 and/or for the gear pump 7 run directly via the connection location 110.

(36) An activation 195′ can also be present completely or partly as part of the milk frother appliance, alternatively to incorporating the activation completely or partly in the coffee machine. This alternative is represented in FIG. 10 in a dashed manner. The electrical energy and possibly data signals can then be transmitted from the electronics unit to the activation 195′ via the alternative interface 110′.

(37) The milk frother appliance can be operated as follows.

(38) For the preparation of frothed milk, the gearwheels 17 are firstly wetted inasmuch as the gear pump is dry. For this purpose, a wetting quantity of water-in liquid and/or in the form of steam-controlled by the activation 195 is fed to the gear pump via the cleaning conduit R, in particular by way of delivery by the water pump of the coffee machine amid simultaneous operation of the water heating means and/or on account of the steam pressure of steam, which is produce in the water heating means.

(39) Alternatively or supplementarily to the wetting via the cleaning conduit R, steam can also be fed into the mixing nozzle 79 via the steam feed conduit 90 and can get from there to the gear pump, where the gearwheels are likewise wetted by way of the condensation of the steam, and the delivery of steam is also effected by way of the water pump and/or the steam pressure. As is shown in FIG. 10, the steam feed conduit can herein run out into the mixing nozzle 79 downstream of the gearwheels 7 or however alternatively also run out into the milk conduit upstream of the gearwheels or be admixed via a mixing nozzle, which lies upstream of the gearwheels.

(40) The gear pump is brought into motion subsequent to the wetting, whilst for example air is sucked via the valve unit 20 (alternatively via a valve unit in the base unit 101 and via a suitable conduit crossing the docking element). A vacuum is produced at the inlet side of the gear pump due to the effect of this pump, and this vacuum sucks milk-through the milk suction tube 18 and the respective duckbill valve 42-as well as air. The air valve can firstly remain closed for 1-3 s and therefore milk firstly be sucked into the pump, in order to increase the reliability of the sucking of the milk. Milk froth therefore arises in the gear pump as soon as the air valve is opened and this froth gets through the feed-through 36-whose narrowness encourages the formation of fine-pored froth-, the outgoing conduit and the docking element 25 to the milk froth outlet 28 and is dispensed there, wherein generally a drinks vessel 200 is placed upon the platform 103.

(41) Inasmuch as the milk is only to be delivered but not frothed, the operation of the gear pump is effected without the sucking of air (closed valve unit).

(42) The sucking of the-generally cold-milk out of the milk container 3 via the gear pump is also effected for the preparation of warm frothed milk or unfrothed milk. This gear pump delivers the milk into the mixing nozzle. Steam from the coffee machine is simultaneously fed to this nozzle via the steam connection. Optionally, air can also be fed to this mixing nozzle supplementarily or alternatively to the feed of air to the gear pump. The milk is mixed with the steam in the mixing nozzle 79, wherein the steam heats the milk. The warm, frothed or unfrothed milk is also delivered through the milk froth outlet.

(43) If the gear pump is already moist-which would be the case, for example, if a wetting and/or a use has already taken place since the last starting or since the last waking from a sleep mode, without the milk frother appliance having been removed in the meanwhile-the step of the wetting can be skipped. Other criteria can also be used, in order to determine whether the gear pump is dry or whether the gearwheels are already moistened—for example the time since the last use/wetting of the gear pump, said time being measured by a timer, by a humidity measurement, by a measurement entailed by a short test run (for example with a shaking sensor that determines a pattern which, when the pump leaks, is different to when its runs in a correct manner), etc.

(44) In the represented embodiment example, the drinks preparation machine 100 with the base unit and the milk frother appliance forms the milk frother system according to the invention. Alternatively, it would also be possible to provide a milk frother appliance, which itself includes a control, an electricity connection and a water heater or steam generator, without a connection to the base unit and according to the invention is configured to wet the gearwheels of the gear pump before an operation, in particular when they are dry.

LIST OF REFERENCE NUMERALS

(45) 1 milk frother appliance
3 milk container 5 milk frothing unit 6 cover 7 gear pump 11 lower base housing part 12 window 13 electric motor 14 upper base housing part 15 arching (in the milk frothing unit cover) 16 milk frothing unit cover 17 gearwheels 18 milk suction tube 19 shaft 20 valve unit 21 seal 22 connection shaped part 23 spacer 24 motor seal element 25 main body (of the docking element) 26 docking element housing 27 supplementary part 28 milk froth outlet 31 liquid conduit 32 hot water and/or steam feed conduit 34 air feed conduit 35 outgoing conduit 36 feed-through 41 duckbill valve 42 duckbill valve 43 duckbill valve 51 channel for hot water and/or steam feed conduit 52 channel for air feed conduit 53 channel for outgoing conduit 79 mixing nozzle 90 steam feed conduit into the mixing nozzle 100 drinks preparation machine 101 coffee machine 103 placement platform 105 coffee outlet 106 front 107 milk frother platform 108 outlet hood 110 connection location 110′ alternative interface 121 electronics unit 195 activation 195′ alternative activation 200 drinks vessel