Patent Description:
Coffee machines are widely available commercially today comprising a milk container having a Venturi-effect milk-emulsifying device, such device is for example disclosed in <CIT>.

These coffee machines are designed to obtain an emulsion of hot milk in a cup.

In practice the steam produced by a boiler of the coffee machine is fed into a mixing chamber provided in the emulsifying device where the Venturi effect creates a vacuum that draws milk from a suitable container of the milk and air from the external atmospheric environment.

Typically, the temperature of the milk emulsion is significantly greater than the environmental temperature of <NUM> and this is due to the fact that the steam required to trigger the Venturi effect has the further effect of heating the milk.

In fact, typically, a milk emulsion can be produced at a final temperature in the cup comprised between <NUM> and <NUM>.

It has been ascertained that the temperature of a foodstuff affects the perception of the taste that occurs in the taste buds of the tongue and is completed with the aroma perceived by the receptors of the nasal mucous.

In fact, in the mouth, the temperature of the food or of the beverage modifies the microscopic channels of the taste buds and the sending of the signal to the brain through the taste nerves.

Below <NUM>, the taste buds are almost paralysed, whereas at <NUM> the sensitivity of the taste buds increases over <NUM> times and for this reason the sweet taste of an ice cream is perceived only when it melts in the mouth.

On the other hand, hot food emits vapours that reach the nasal mucous and contribute about <NUM>% to the perception of taste, but if the temperature exceeds <NUM>, the perception of taste decreases, because the sensation of burning hides the tasting nuances.

The technical task addressed by the present invention is thus to make a coffee machine adapted to heighten the perception of the taste of the dispensed milk emulsion.

Within the context of this technical task, an aim of the invention is to make a coffee machine that is suitable for dispensing a milk emulsion at low temperature. Another aim of the invention is to make a coffee machine having a milk-emulsifying device that is easy to clean.

A further aim of the invention is to make a coffee machine having a kit of interchangeable milk emulsifying devices for producing milk emulsion at low temperature and at high temperature.

The technical task, and these and other aims according to the present invention are achieved by making a coffee machine comprising a water tank, a boiler for the production of steam, a water supply pump for supplying water to the boiler for generation of steam, an external coffee dispenser, an external steam dispenser having a dispensing opening for dispensing a steam flow, a milk container having an emulsifying device for emulsifying the milk by Venturi effect generated by the steam flow, said emulsifying device having a mixing chamber for mixing milk/steam/air, a milk aspirating channel by Venturi effect having an inlet opening into the mixing chamber, an air aspirating channel by Venturi effect having valve means and an inlet opening into the mixing chamber, said mixing chamber having a sealed removable connection opening with the external steam dispenser and an outlet opening of the milk emulsion aligned to the steam dispensing opening and connected to an external dispenser of the milk emulsion, wherein the outlet opening of the milk emulsion is larger than the steam dispensing opening for the activation of the Venturi effect, characterised in that said minimal passage area of said milk aspirating channel has a diameter not less than <NUM>, the dispensing opening area of the external steam dispenser has a diameter comprised between <NUM> and <NUM>, the outlet opening area has a diameter comprised between <NUM> and <NUM>, an air inlet opening in the air aspirating channel adjustable by said valve means has, in a maximum opening configuration, a diameter comprised between <NUM> and <NUM>, and said external steam dispenser is configured to dispense a steam flow comprised between <NUM>/s and <NUM>/s at a steam temperature comprised between <NUM> and <NUM> and at a steam pressure comprised between <NUM> and <NUM> atm.

The present invention also discloses a dispensing method for dispensing a milk emulsion into a cup with a coffee machine comprising a water tank, a boiler for the production of steam, a water supply pump for supplying water to the boiler for generation of steam, an external coffee dispenser, an external steam dispenser having a dispensing opening for dispensing a steam flow, a milk container having an emulsifying device for emulsifying the milk by Venturi effect generated by the steam flow, said emulsifying device having a mixing chamber for mixing milk/steam/air, a milk aspirating channel by Venturi effect having an inlet opening into the mixing chamber, an air aspirating channel by Venturi effect having valve means and an inlet opening into the mixing chamber, said mixing chamber having a sealed removable connection opening with the external steam dispenser and an outlet opening of the milk emulsion aligned to the steam dispensing opening and connected to an external dispenser of the milk emulsion, wherein the outlet opening of the milk emulsion is larger than the steam dispensing opening for the activation of the Venturi effect, characterised in dispensing a flow of milk emulsion having a value comprised between <NUM>/s and <NUM>/s at a temperature no more than <NUM> higher than the temperature of the milk present in the milk container by means of a reduced thermal energy contribution of the steam used to milk aspiration corresponding to a weight of condensed steam in the milk emulsion between <NUM>% and <NUM>% greater than the weight of the milk aspirated from the milk container.

In one embodiment of the invention a flow of milk emulsion is dispensed having a value comprised between <NUM>/s and <NUM>/s at a temperature no more than <NUM> higher than the temperature of the milk present in the milk container.

In one embodiment of the invention said container is filled with milk having a temperature comprised between <NUM> and <NUM>.

In one embodiment of the invention, said milk container has thermal insulation.

In one embodiment of the invention, said milk aspirating channel is interchangeable with a milk aspirating channel having a smaller minimal passage area.

In one embodiment of the invention, said valve means are interchangeable with valve means that provides an adjustable inlet opening for the entry of air into the air aspirating channel, having in a maximum opening configuration a smaller area. In one embodiment of the invention, the coffee machine has a cup resting surface, the external coffee dispenser is configured and arranged for direct dispensing into a cup positioned on the cup resting surface, and the external milk emulsion dispenser is configured and arranged for direct dispensing into said cup.

Further features and advantages of the invention will become more apparent from the description of a preferred, but not exclusive, embodiment of the coffee machine according to the invention, which is illustrated by way of approximate and nonlimiting example in the attached drawings, of which:.

With reference to the figures cited, a coffee machine is shown and indicated in its entirety by reference number <NUM>.

The coffee machine <NUM> comprises a water tank <NUM>, boiler <NUM> for the production of steam, a water supply pump <NUM> for supplying water to the boiler <NUM> for generation of steam, an external coffee dispenser <NUM>, an external steam dispenser <NUM>, and a milk container <NUM> having an emulsifying device <NUM> for emulsifying the milk by Venturi effect.

The external steam dispenser <NUM> is configured to dispense a steam flow comprised between <NUM>/s and <NUM>/s at a temperature comprised between <NUM> and <NUM> and at a pressure comprised between <NUM> atm and <NUM> atm.

Preferably, the coffee machine <NUM> is configured to dispense the milk emulsion directly into the cup and for this purpose features a cup resting surface <NUM> on which also the milk container <NUM> rests.

In particular, the external coffee dispenser <NUM> is configured and arranged for direct dispensing into a cup below positioned on the cup resting surface <NUM>, and the emulsifying device <NUM> has an external dispenser of the milk emulsion <NUM> which is also configured and arranged for direct dispensing into the cup.

The emulsifying device <NUM> has a mixing chamber <NUM> for mixing milk/steam/air, a milk aspirating channel <NUM> for aspirating the withdrawn milk by Venturi effect from the milk container <NUM> and having an inlet opening <NUM> into the mixing chamber <NUM>, an air aspirating channel <NUM> by Venturi effect having valve means <NUM> and an inlet opening <NUM> into the mixing chamber <NUM>, a sealed removable connection opening <NUM> with the external steam dispenser <NUM>, and an outlet opening <NUM> of the milk emulsion connected to the external dispenser <NUM> of the milk emulsion.

The emulsifying device <NUM> is integrated into an extractable cover <NUM> of the milk container <NUM>, but in one version it can be integrated directly into the milk container <NUM>.

The outlet opening <NUM> is positioned on the extension of the axis L of the external steam dispenser <NUM> whilst the milk inlet opening <NUM> and the air inlet opening <NUM> are arranged radially and on the side opposite the extension of the axis L of the external steam dispenser <NUM>.

The milk aspirating channel <NUM> can consist at least partially of a structurally independent tubular piece stiffly connected to the body of the mixing chamber <NUM> and extending as far as the bottom of the milk container <NUM>.

The external dispenser of the milk emulsion <NUM> can consist at least partially of a structurally independent tubular piece connected rotatably to the body of the mixing chamber <NUM> between a rest position and a dispensing position.

The valve means <NUM> can comprise a shutter and a knob <NUM> for driving thereof adapted to close or open in an adjustable manner the air aspirating channel <NUM>. The shutter in the case under examination consists of a hollow stem <NUM> that extends coaxially and solidly constrained to the knob <NUM>.

The hollow stem <NUM> is in turn housed coaxially in the air aspirating channel <NUM> and engages peripherally with a tilted internal perimeter rib <NUM> of the air aspirating channel <NUM>.

The tilted rib <NUM> can be formed on a removable portion of the air aspirating channel <NUM>.

The hollow stem <NUM> is provided with an air inlet opening <NUM> in the air aspirating channel <NUM>.

The air inlet opening <NUM> in the air aspirating channel <NUM> is configured as a slit that extends in the axial direction of the hollow stem <NUM>.

The atmospheric air enters the cavity of the stem <NUM> through the slit and the cavity of the stem <NUM> communicates directly with the inlet opening <NUM> for the entry of the air into the mixing chamber <NUM>.

The rotation of the knob <NUM> on its axis varies the intersection position of the slit with the tilted rib <NUM> and then varies the section of the slit that is used for the entry of air into the aspirating channel <NUM>.

The section of the slit used for the entry of the air into the air aspirating channel <NUM> is in fact the section comprised between the apex of the slit and the point where the slit intersects the rib <NUM>.

The air aspirating channel <NUM> is closed when the tilted rib <NUM> is positioned at an upper apex of the slit.

Starting from this position, as the knob <NUM> is rotated, a progressively increasing section of the slit opens and then an inlet area for the entry of the air into the air aspirating channel <NUM> grows progressively up to a maximum value.

Downstream of the slit, the air passage area along the air aspirating channel is the same as or greater than the aforesaid maximum value.

It is clear that the amount of the increase of the inlet area for the entry of the air into the air aspirating channel <NUM> is correlated with the width of the slit, the wider the slit, the greater the inlet area for the entry of the air into the air aspirating channel <NUM> and the maximum value thereof.

The milk aspirating channel <NUM> has a minimal passage area sufficiently large as to ensure the dispensing of a milk emulsion having a weight of between <NUM>% and <NUM>%, still better between <NUM>% and <NUM>% greater than the weight of the milk aspirated from the milk container <NUM>, the additional weight of the milk emulsion compared to the aspirated milk being that of the condensed steam included into the milk emulsion. In particular, the milk aspirating channel <NUM> has a minimal passage area sufficiently large as to ensure the dispensing of a flow of milk emulsion having a value comprised between <NUM>/s and <NUM>/s.

The milk inlet opening <NUM> is circular and has a diameter not less that <NUM>, preferably comprised between <NUM> and <NUM>.

The milk aspirating channel <NUM> has a minimum inner cross section that is not less than the inlet opening of the milk <NUM>.

The dispensing opening <NUM> of the external steam dispenser <NUM> is circular and has a diameter comprised between <NUM> and <NUM>, preferably between <NUM> and <NUM>, and is lower than the outlet opening <NUM>.

The air aspirating opening is circular and has a diameter comprised between <NUM> and <NUM>.

The valve means <NUM>, as said, adjusts the air passage area along the air aspirating channel <NUM>.

The inlet opening <NUM> of the air in the air aspirating channel <NUM>, in a maximum opening configuration, has an equivalent diameter comprised between <NUM> and <NUM>.

Equivalent diameter means the diameter of a circular area of the same size as the area of the inlet opening <NUM> for entry of the air into the air aspirating channel <NUM>. The outlet opening <NUM> is circular and has a diameter comprised between <NUM> and <NUM>, preferably between <NUM> and <NUM>.

The emulsifying device <NUM> by Venturi effect can thus have great milk aspiration efficiency with an aspirated milk flow of not less than <NUM>/s.

With the milk aspirating channel <NUM> that is thus dimensioned, a milk emulsion is obtained at a temperature that is not higher than <NUM> when the temperature of the milk present in the milk container <NUM> is comprised between <NUM> and <NUM>.

In order to maintain the temperature at a value that is significantly below ambient temperature, the milk container <NUM> can have thermal insulation.

The milk emulsifying device can have interchangeable parts for dispensing a hotter milk emulsion.

In particular, the air adjusting valve means and preferably also the milk aspirating channel can be interchangeable.

The comparison between the air adjusting valve means and the milk aspirating channel illustrated in <FIG> and <FIG> with the means illustrated in <FIG> and <FIG> clarifies better, also visually, the difference.

In fact, for producing a hotter milk emulsion, the milk aspirating channel illustrated in <FIG> and <FIG> is used, that, having a lower minimal passage area, for example at the end of the interchangeable part, lowers the efficiency of milk aspiration by Venturi effect.

Further, again for producing a hotter milk emulsion, valve means illustrated in <FIG> can be used that provides a smaller maximum passage area of the inlet opening <NUM> for entry of the air into the air aspirating channel <NUM> because the slit has a reduced width.

With these replacements, a milk emulsion can be produced at a final temperature in the cup comprised between <NUM> and <NUM>.

The method for dispensing the milk emulsion increases the efficiency of milk aspiration by Venturi effect by increasing, with respect to a traditional emulsifying device that produces a hotter milk emulsion, the minimal passage area of the milk aspirating channel up to a value corresponding to dispensing a milk emulsion having a weight of between <NUM>% and <NUM>% greater than the weight of the milk aspirated from the container, and a flow of milk emulsion having a value comprised between <NUM>/s and <NUM>/s.

Compared to prior art emulsifying devices by Venturi effect for aspirating milk and air in the mixing chamber, the minimal passage area of the milk aspirating channel is now increased up to a value corresponding to the dispensing of a milk emulsion at a temperature that is not higher than <NUM> when the temperature of the milk present in the milk container is comprised between <NUM> and <NUM> and the steam dispensed by the external steam dispenser <NUM> has a temperature comprised between <NUM> and <NUM> and a pressure comprised between <NUM> atm and <NUM> atm. The coffee machine as conceived herein is susceptible to many modifications and variations, all falling within the scope of the inventive concept; further, all the details are replaceable by technically equivalent elements.

For example, the various openings disclosed above, also those that are disclosed for example as having a circular shape, can have a non-circular shape and in this case diameter is to be intended to be the equivalent diameter, i.e. the diameter of a circle that has substantially the same non-circular opening area.

Claim 1:
A dispensing method for dispensing a milk emulsion into a cup with a coffee machine (<NUM>) comprising a water tank (<NUM>), a boiler (<NUM>) for the production of steam, a water supply pump (<NUM>) for supplying water to the boiler (<NUM>) for generation of steam, an external coffee dispenser (<NUM>), an external steam dispenser (<NUM>) having a dispensing opening (<NUM>) for dispensing a steam flow, a milk container (<NUM>) having an emulsifying device for emulsifying the milk by Venturi effect generated by the steam flow, said emulsifying device (<NUM>) having a mixing chamber (<NUM>) for mixing milk/steam/air, a milk aspirating channel (<NUM>) by Venturi effect having an inlet opening (<NUM>) into the mixing chamber (<NUM>), an air aspirating channel (<NUM>) by Venturi effect having valve means (<NUM>) and an inlet opening (<NUM>) into the mixing chamber (<NUM>), said mixing chamber (<NUM>) having a sealed removable connection opening (<NUM>) with the external steam dispenser (<NUM>) and an outlet opening (<NUM>) of the milk emulsion aligned to the steam dispensing opening (<NUM>) and connected to an external dispenser (<NUM>) of the milk emulsion, wherein the outlet opening (<NUM>) of the milk emulsion is larger than the steam dispensing opening (<NUM>) for the activation of the Venturi effect, characterised in dispensing a flow of milk emulsion having a value comprised between <NUM>/s and <NUM>/s at a temperature no more than <NUM> higher than the temperature of the milk present in the milk container (<NUM>) by means of a reduced thermal energy contribution of the steam used to milk aspiration, said milk emulsion having a weight of between <NUM>% and <NUM>% greater than the weight of the milk aspirated from said milk container (<NUM>), the additional weight of said milk emulsion compared to the aspirated milk being that of the condensed steam included into said milk emulsion.