AN EMULSIFYING DEVICE

Technical field of the invention

The present invention generally relates to machines for the preparation of infused beverages, such as e.g. coffee, starting from pods or capsules, and more particularly to a machine of this type comprising an emulsifying device.

Background

Machines for the preparation of infused beverages such as espresso coffee starting from pods and/or capsules are known. These machines comprise emulsifying devices for the preparation of milk foam or cream from fresh milk contained in a reservoir, for example for the preparation of beverages such as cappuccino, milky coffee and the like.

The emulsifying devices typically comprise a nozzle connected or connectable to an outlet conduit of a steam delivery circuit of a machine. The nozzle includes a narrowing portion at which a branch portion is formed. It is known that a flow of steam passing through the narrowing portion generates a pressure drop that allows you to suck by Venturi effect fresh milk contained in a first container such as e.g. a carafe, through its branch portion. The fresh milk sucked by the carafe is heated and emulsified by the steam flow crossing the nozzle, is dispensed from an outlet thereof and collected in a second reservoir such as a cup.

Also known are machines for the preparation of infused beverages comprising reservoirs for fresh milk that can be connected in a removable manner to the respective emulsifying device. These reservoirs comprise a lid provided with an attachment member configured to be connected to the branch portion of the nozzle of the emulsifying device. A suction tube extending to the bottom of the reservoir is restrained to the attachment member inside the lid.

The outlet of the nozzle may be accessible directly from the outside of the machine, for example when it is arranged close to the reservoir connected to the emulsifying device, or may be configured to be connected to the reservoir. In the latter case the lid of the reservoir is provided with a further attachment member configured to be connected to the nozzle of the emulsifying device, as well as with a dispensing channel formed in the lid, which allows to channel the beverage towards a cup or similar receptacle.

The international publication WO 2015/197261 Al describes an example of a machine for preparing beverages having foamy or creamy milk by using fresh milk contained in a reservoir. The machine comprises an outlet conduit of a steam dispensing circuit and a Venturi assembly connectable in a removable manner to the outlet conduit. The Venturi assembly has the same function of a dispensing nozzle of a conventional machine and is configured to be connected to a milk reservoir. With reference to the steam flow direction the assembly comprises in sequence a Venturi tube coupled to the outlet conduit of the machine, an emulsifying chamber arranged downstream of the Venturi tube and a dispensing outlet. Milk is sucked from the tank due to the pressure drop generated by the steam flowing through the Venturi tube and is mixed with the steam in the emulsifying chamber before exiting therefrom in the form of foam or cream via the dispensing outlet.

The use of reservoirs connectable to a machine for dispensing infused beverages is advantageous, because it allows a user to store fresh milk in a closed container which can in turn be stored in a refrigerator, being it no longer necessary to pour fresh milk in a receptacle which is temporarily placed near the machine and must then be emptied and washed after the dispensing step.

The possibility to connect a reservoir to the nozzle of the emulsifying device and to its branch portion is advantageous because it allows to reduce the number of steps a user has to carry out.

The density and temperature of the foam or cream are typical problems of the emulsifying devices for machines for preparing infused beverages. Density and temperature are not always suitable for the preparation of beverages such as milky coffee, cappuccino and the like. Milk foam in fact often comprises bubbles of a relatively large size, and thus features a low density and a temperature that is considerably lower than the temperature of the infused beverage dispensed by the machine. This affects the organoleptic properties of the final beverage.

Another typical problem of the emulsifying devices is that the steam flow typically has a high pressure and is accelerated by Venturi effect when crossing the nozzle. This can generate sprays of milk that foul the surfaces surrounding the reservoir intended to receive the beverage.

A further problem is that cleaning of the components of the emulsifying devices and of the reservoir lid that can be connected thereto is often difficult due to their conformation.

Summary of the invention

The technical problem posed and solved by the present invention is therefore to provide a machine for the preparation of infused beverages provided with an emulsifying device which allows to overcome the drawbacks mentioned above with reference to the prior art.

This problem is solved by a machine according to claim 1.

Preferred features of the present invention are object of the dependent claims. In the emulsifying device of the machine according to the invention the nozzle comprises a cylindrical insert housed in a cavity having a matching shape that is arranged between the narrowing portion and an outlet free end. The insert comprises a plurality of alternating transverse through openings and annular protrusions contacting the walls of the nozzle cavity. The annular protrusions comprise at least one notch or indentation which defines with the cavity walls a flow passage suitable to put in fluid communication consecutive transverse through openings. The notches or indentations are arranged relative to an axis of the cavity such that the flow of fluid through consecutive transverse through-openings of the insert occurs in opposite directions. The path of the mixture of steam and milk inside the nozzle is therefore not straight as it happens in the nozzles of prior art machines, but meandering.

The main advantage offered by the invention is to facilitate heating of the flow of fluid while reducing its pressure. In fact, compared to the substantially straight and direct outlet path that characterizes the nozzles of the emulsifying devices known in the art, in this case the fluid outlet path is considerably longer, which results in longer residence times allowing to promote heating.

The meandering fluid path also results in a head loss of the fluid flow, whereby the pressure at the nozzle outlet is lower than the pressure of the steam delivery circuit. The risk of spraying is therefore reduced.

In addition to this, the meandering path promotes breaking of air bubbles present in the fluid, thereby allowing to form a denser foam for the benefit of the organoleptic properties of the beverage produced by the machine.

The insert is made of a resilient polymeric material, preferably silicone, which facilitates its assembly into the nozzle cavity. Moreover, resilient polymeric materials such as silicone feature a low thermal conductivity, which allows to limit thermal losses for the benefit of the heating of the milk sucked through branch portion of the nozzle.

A further advantage of resilient polymeric materials such as silicone is to have a damping effect on the vibrations generated by the flow of steam and milk crossing the nozzle, thereby making dispensing of the milk foam less noisy of compared to prior art emulsifying devices.

Another advantage of using a resilient polymeric material such as silicone is the ease of manufacturing of the insert by way of injection molding even in the presence of undercuts.

Brief description of the drawings

Reference will be made to the figures of the attached drawings, wherein:

figures 1 to 3 are perspective views showing a machine according to the invention for the preparation of infused beverages and a reservoir that can be connected to an emulsifying device of the machine;

figures 4 to 6 are perspective exploded views showing the components of the emulsifying device according to the invention and the components of a lid of the container;

figures 7 and 8 are side, longitudinal section views taken along a plane passing through line VII- VII and along a plane passing through line VIII- VIII of figure 1, respectively;

figure 9 is a bottom perspective view of the container lid.

Detailed description of preferred embodiments Figures 1 to 4 show a machine 100 for dispensing infused beverages. These beverages may e.g. be prepared by using capsules or pods containing a measured dose of a food product in a powder form, for example coffee. The capsules or pods are introduced in a brewing unit (not shown) that is selectively accessible through a door 110 e.g. arranged atop the machine 100.

The machine 100 comprises in a known manner a dispensing head 120 from which a beverage prepared in the brewing unit is dispensed towards an underlying receptacle, such as a cup.

The machine 100 also comprises in known manner an emulsifying device 200 that is connected or connectable to a steam delivery circuit having an outlet conduit 130 which ends for example aside the dispensing head 120, as shown in figure 4.

In the following reference will be made to an emulsifying device 200 fixedly connected to the dispensing machine 100, but, as it will be clear from the description below, this is not a limiting feature of the invention, because the same emulsifying device could be restrained in a removable manner to the outlet conduit 130 of the steam delivery circuit.

With reference to figures 4 to 6, the emulsifying device 200 comprises in a known manner a nozzle 210 having a substantially cylindrical shape and connected to the outlet conduit 130 so as to allow dispensing of steam from the machine 100. The nozzle 210 has a narrowing portion 211, i.e. a portion having smaller diameter than its nominal diameter, in correspondence of which a branch portion 212 is formed. The branch portion allows to suck by Venturi effect a flow of fluid, typically fresh milk contained in a first reservoir such as e.g. a carafe. The fluid is typically sucked through a tube connected to a free end 212a of the branch portion 212 and is dispensed from an outlet free end 210a of the nozzle 210.

According to the invention the nozzle 210 comprises an insert 220 housed in a cavity 210b thereof formed between its outlet free end 210a and the narrowing portion 211. In other words, the insert 220 is arranged downstream of the narrowing portion 211 of the nozzle 210 with respect to the steam flow direction, so that in operation it is crossed by a mixture of milk and steam.

Now referring to the longitudinal sections shown in figures 7 and 8, the insert 220 has a shape matching the shape of the cavity 210b formed in the nozzle 210, for example a cylindrical shape, and comprises a plurality of alternating through openings 221, which are formed transversely to its axis, and protrusions 222 having an annular shape, which contact the walls of the cavity 210b of the nozzle 210 in an assembled configuration. The annular protrusions 222 comprise respective circumferential notches which define with the walls of cavity 210b axial flow passages for the mixture of steam and milk.

The circumferential notches 222 are arranged such that consecutive flow passages in the axial direction are diametrically opposite to each other, so that the flow direction of the mixture of steam and milk from a through opening 221 to the next one is reversed.

In other words, the insert 220 configured as described above defines with the cavity 210b of the nozzle 210 a meandering path for the mixture of steam and milk crossing it. In fact, the mixture of steam and milk passes through the insert 220 transversely to its axis in correspondence of each through opening 221 and proceeds from a through opening 221 to the next one through the flow passages defined by the circumferential notches of the annular protrusions 222 by reversing its transverse movement direction. The path of a fluid flowing through the nozzle is schematically shown in figure 7 by way of arrows.

Compared to the substantially direct and axial outflow that characterizes the nozzles of prior art emulsifying devices, such as the emulsifying device of the machine described in the international publication WO 2015/197261 Al, in this case the flow path of the mixture of steam and milk is considerably longer, which results in longer residence times which enhance its heating.

The tortuosity of the meandering path also causes a head loss in the flow of the mixture, so that its pressure at the outlet free end 210a of the nozzle 210 is lower than the nominal pressure of the steam delivery circuit, thereby reducing risks of spraying.

In addition to this, the conformation of the meandering path promotes breaking of air bubbles present in the fluid, which allows to achieve a denser foam for the benefit of the organoleptic properties of the beverage produced by the machine 100.

According to a preferred embodiment of the invention, the insert 220 is made of a resilient polymeric material, preferably silicone, which, as mentioned above, facilitates its tight assembly into the cavity 210b of the nozzle 210 and allows to limit heat losses. This improves heating of the milk sucked through the branch portion 212 of the nozzle 210.

According to a preferred embodiment, the free end 210a of the nozzle 210 is removable so as to allow to withdraw the insert 220 from its cavity 210b for the purpose of cleaning and/or replacement.

For aesthetic reasons and considering size issues, the nozzle 210 and its branch portion 212 are preferably housed in a seat 140 formed in the machine body 100 aside the dispensing head 120, where the steam delivery conduit 130 protrudes. The seat 140 is closed by a cover 150 comprising two openings 151, 152 configured for the tight connection of the free end 210a of the nozzle 210 and the free end 212a of the its branch portion 212.

The machine 100 may further comprise a container 300 provided with a lid 310 and a milk reservoir 320, and comprising at least one attachment member configured to be tightly connected to the opening 152 of the cover 150 that is in fluid communication with the branch portion 212 of the nozzle 210 so as to allow milk supply.

In the illustrated embodiment, the container 300 is configured to be connected to both openings 151 and 152 and to this aim its lid 310 is provided with a pair of attachment members 31 1, 312 configured to tightly engage the openings 151, 152, respectively.

With particular reference to figures 5, 6 and 9, inside the lid 310 two pipes made of a resilient polymeric material, preferably silicone, are arranged.

A first pipe 401 is connected to the attachment member 311 and is thereby put in fluid communication with the free end 210a of the nozzle 210 so as to allow dispensing of milk foam produced by the nozzle from the container 300. The first pipe 401 protrudes from the lid 310 through an opening 313 thereof at which a hollow arm 314 is formed. The hollow arm 314 houses and guides the pipe 401 and comprises a bent end portion 314a that faces downwards in an assembled configuration of the container 300 so as to direct the flow of milk foam into a receptacle such as a cup.

As shown in figure 9 one or more ribs 314b may be advantageously formed in the bent end portion 314a of the hollow arm 314 so as to interfere with the flow of milk foam in order to reduce its velocity and further break its bubbles for the benefit of the foam quality.

As described above, it will be appreciated that due to the arrangement of the emulsifying device 200 on the machine 100, the container 300 connected thereto is arranged aside the dispensing head 120. Advantageously, the through-opening 313 and the hollow arm 314 can be formed in the lid 310 on the face contiguous to the face where the attachment members 311, 312 for the assembly of the container 300 to the emulsifying device 200 are formed. This face is oriented towards the dispensing head 120, thereby allowing to dispense milk foam directly into a receptacle that is arranged under the dispensing head 120 in order to receive the infused beverage. Hence, there is no need to move the receptacle to a different location.

A second pipe 402 is instead is connected to the attachment member 312 of the lid 310 of the container 300 and extends vertically along the container 300 up to a bottom wall 321 thereof so as to allow to suck milk.

Still referring to figure 1, according to a further aspect of the invention a movable door 153 can be advantageously associated to the cover 150. The door 153 may e.g. be slidably connected to the cover 150.

In the absence of the container 300, due to the force of gravity the door 153 is in a closed position wherein it covers the openings 151, 152 thus protecting them against ingress of dust. Figure 1 shows the door 153 arranged in an open position wherein the openings 151 and 152 may be accessed to connect the container 300 to the machine 100.

The door 153 may advantageously comprise means for actuating a switch (not shown) of the steam delivery circuit, for example in the form of a magnet (not shown), configured to inhibit operation of a boiler of the machine when the door 153 is in the closed position.

The present invention has hereto been disclosed with reference to preferred embodiments. It will be appreciated that there may be further embodiments relating to the same inventive idea, as defined by the scope of protection of the claims set out below.