TECHNICAL FIELD

The present invention relates to a coffee machine, preferably a fully automatic coffee machine.

More particularly, the present invention relates to a fully automatic coffee machine which is adapted to prepare several kinds of different coffee-based drinks.

The present invention also relates to a method for operating such coffee machine.

BACKGROUND ART

Fully automatic coffee machines, also called “coffee automats” are known and widespread, especially in the restaurant industry.

Such coffee machines work in a fully automatic way, i.e. it is sufficient that the user presses a button on an interface of the coffee machine for starting and carrying out the whole process of preparation of a coffee-based drink. This process essentially comprises the following steps: grinding the exact amount of coffee beans; accumulating the ground coffee powder in a suitable chamber; compacting and compressing the coffee powder until forming a “cake”; sending a dosed water flow at a predetermined temperature and pressure through said “cake”; collecting the coffee infusion and sending it downstream towards an outlet spout; dispensing the coffee infusion through said spout into a cup, or similar container.

Other ingredients, such as cocoa powder, milk, frothed milk, flavoring agents, and the like, may optionally be added to the coffee infusion, either in the coffee machine or directly in said cup or container, for obtaining the desired coffee-based drink.

Fully automatic coffee machines are known, in which the properties of the dispensed drink can be modified and adjusted by intervening on one or more operating parameters of the coffee machine.

For instance, the coarseness and the amount of the ground coffee powder can be modified by adjusting the grinding time and/or the position of the grinding burrs.

In addition or in alternative, the properties of the dispensed drink can be modified by adjusting the brewing temperature and/or the brewing pressure in the brewing chamber.

In order to increase the versatility of these machines, fully automatic coffee machines that are adapted to dispense different kinds of coffee-based drinks have also been developed.

Such coffee machines are capable, for instance, of dispensing both espresso coffee (the preparation of which requires a high brewing pressure) and American coffee (the preparation of which requires a low brewing pressure for avoiding formation of “crema”). Furthermore, such coffee machines are capable, for instance, of dispensing coffee-based drinks starting from different coffee blends.

U.S. Pat. No. 6,101,923 discloses a fully automatic coffee machine in which coffee beans are received in a container having a partition wall defining two separate compartments, which allows two different blends of coffee to be used. In order to prepare a coffee-based drink starting from the desired coffee blend, each compartment of this container is connected through its own funnel to a separate, dedicated grinder. The freshly ground powder thus obtained can successively be supplied to a first or to a second brewing chamber for the preparation of the desired coffee-based drink.

US 2010/0224075 discloses a fully automatic coffee machine comprising at least two brewing groups for producing a coffee beverage, which groups are independent from each other and can be separately controlled, a device for the preparation and distribution of the coffee powder to the brewing groups, as well as a common coffee dispensing outlet. Each brewing group has a different geometry, as it has been found that the quality of a specific coffee-based drink can be improved by an appropriate brewing group geometry. The coffee machine further comprises several storage containers which hold different sorts of coffee beans, so that, thanks to the possibility of selecting the sort of coffee beans and the brewing group, a large variety of coffee-based drinks can be produced.

Although allowing to effectively obtain several kinds of different coffee-based drinks, the above-described coffee machines are not free from drawbacks.

These machines are generally bulky objects, which take a large amount of space and are often incompatible with modern and attractively designed restaurants.

Moreover, these machines include a high number of mechanical components, which involve a large amount of maintenance. The need for maintenance is also increased by the fact that, during use, such mechanical components are contaminated with coffee powder and exposed to water and coffee infusions.

The main object of the present invention is therefore to provide a coffee machine, preferably a fully automatic coffee machine, which is capable of dispensing different kinds of coffee-based drinks and, at the same time, has a compact construction.

Another object of the present invention is to provide a coffee machine, preferably a fully automatic coffee machine, having a limited number of mechanical components, so that the frequency of maintenance can be accordingly reduced.

These and other objects are achieved by a coffee machine as claimed in the appended claims.

SUMMARY OF INVENTION

According to the invention, the coffee machine comprises several coffee bean containers for receiving different blends of coffee, a single grinder for selectively grinding the coffee beans coming from one of said containers, and a single brewing chamber for receiving the coffee powder coming from said grinder and preparing the desired coffee-based drink.

Thanks to the provision of a single grinder and a single brewing chamber, the coffee machine according to the invention has an extremely compact construction.

The coffee machine according to the invention further comprises an interface through which the user can select a desired coffee-base drink among a plurality of different coffee-based drinks.

The coffee machine according to the invention further comprises a control unit that is arranged to control one or more operating parameters of the coffee machine according to the selection inputted by the user.

The coffee machine according to the invention further comprises a memory unit, in which the recipes of the available coffee-based drinks are stored.

In this context, “recipe” means not only the list of ingredients and preparation steps of each coffee-based drink, but also the list of values or ranges of values of the operating parameters of the coffee machine (with particular reference to the selecting unit, the grinding unit and the brewing unit of said coffee machine) that are to be set in order to correctly carry out the preparation process of said drink.

According to a preferred embodiment of the invention, the control unit is arranged to control one or more of the following parameters:position of a selecting element, allowing to selectively connect a specific coffee bean container to the single grinder;position of the grinding elements of the grinder;grinding time;temperature of the water entering the brewing chamber;pressure of the water entering the brewing chamber;flow rate of the water entering the brewing chamber;brewing time.

It will be evident to the person skilled in the art that the coffee machine according to the invention could optionally comprise one or more additional units, such as, for instance, a milk supplying unit for producing frothed milk to be added to the coffee-based drink, a cooling unit for cooling down the coffee-based drink to be dispensed, and so on.

The invention further relates to a method for operating a coffee machine comprising several coffee bean containers for receiving different blends of coffee, a single grinder for selectively grinding the coffee beans coming from one of said containers, and a single brewing chamber for receiving the coffee powder coming from said grinder and preparing the desired coffee-based drinks.

The method according to the invention essentially comprises the steps of:selecting a coffee-based drink;selecting the corresponding coffee bean container according to the selected drink and connecting it to the single grinder;transferring a dose of coffee beans from said coffee bean container to the grinder;adjusting the operating parameters of the grinder, such as the position of the grinding burrs and the grinding time, according to the selected drink;grinding the coffee beans for obtaining the desired dose of coffee powder;transferring said dose of coffee powder to the brewing chamber;adjusting the operating parameters of the brewing chamber, such as the density of the coffee “cake”, the pressure and temperature of the incoming water and the brewing time, according to the selected drink;compacting and compressing said dose of coffee powder for obtaining a coffee “cake”;sending a water flow through said coffee “cake”;collecting the obtained coffee-based drink and dispensing it to the user.

Preferably, the method according to the invention further comprises the step of acquiring the recipe of the selected coffee-based drink and carrying out the successive steps according to the details of said recipe.

In order to correctly prepare coffee-based drinks having different recipes, the coffee machine according to the invention and the method for operating such coffee machine provide for arrangements and solutions allowing to avoid (or at least minimize) contamination between coffee-based drinks that are successively prepared.

By way of example, the connections between the different coffee bean containers and the single grinder are designed so as to effectively avoid mixing of coffee beans coming from different containers.

By way of further example, the grinding time of which the grinder is actuated is set so as to guarantee that no leftovers remain in the grinder at the end of the grinding step.

