DESCRIPTION

Technical Field

The present invention relates to a system for preparing a coffee-based beverage.

More particularly, the present invention relates to a system for preparing a coffee-based beverage comprising a brewing group and means for reducing the temperature of the coffeebased beverage exiting the brewing group.

The present invention also relates to a method for preparing a coffee-based beverage comprising a brewing step and a step of reducing the temperature of the coffee-based beverage obtained from the brewing step.

Background Art

Systems for producing coffee-based beverages are known, allowing to obtain alternatively beverages at a high temperature or beverages at a reduced temperature.

More particularly, said systems generally comprise a brewing group in which the coffeebased beverage is obtained by making (about 85 - 95 °C) stream of water at a high- temperature pass through a coffee powder panel, the coffee-based beverage correspondingly exiting at a high temperature from said brewing group.

The beverage thus obtained can be dispensed directly at the temperature at which it exits the brewing group, or its temperature can be reduced prior to dispensing.

Depending on the needs, such temperature reduction can be more or less intense.

According to some solutions, the beverage can be cooled down to temperatures lower than or equal to ambient temperature and be dispensed and served at said temperatures.

According to other solutions, the beverage can be cooled down to a less extent, in the order of a few tenths of degrees. In this case, the beverage can be served accompanied by ice cubes, and the initial temperature reduction immediately downstream of brewing has the purpose of preventing a sudden melting of the ice and allowing, instead, a slow and gradual melting of the ice cubes.

Several solutions are known for obtaining the desired cooling of the coffee-based beverage. For example, some known solutions envisage to temporarily store the coffee-based beverage in a refrigerating apparatus, in order to reduce the temperature of said beverage.

While, on one part, such solutions allow to adjust the final temperature of the beverage by acting on the dwell time of the beverage in the refrigerating apparatus, on the other part they do not allow to serve a freshly brewed beverage, i.e., a beverage prepared at the time the user orders it.

Other known solutions envisage to mix the beverage obtained in the brewing group with cold water, ice or other coolants.

In this case, too, the final temperature of the beverage can be adjusted by varying the amount of coolant added thereto. However, the addition of a non-negligible amount of water or ice can negatively affect the organoleptic qualities of the resulting beverage. In addition, as mentioned above, the direct addition of ice to the hot beverage and the resulting quick melting of ice therein should be avoided.

Further known solutions envisage to use cooling devices employing, for example, cooling members of the type of Peltier cells, or cooling circuits equipped with a compressor, a condenser and an evaporator.

Such solutions share a high degree of complexity of the means used for cooling down the beverage, which results in high production costs and an increased need for maintenance.

Finally, solutions are known in which the beverage exiting the brewing group exchanges heat with a stream of water (for example, water coming from the water main) in a heat exchanger.

These solutions, besides being simple, have the advantage that - if the water used in the heat exchanger is then used for brewing a beverage dispensed afterwards - the heat released by the hot beverage can be exploited to obtain a pre-heating of water before it enters the boiler.

However, precisely because the same water circuit feeding water to the boiler and then to the brewing group also passes through the heat exchanger, such solutions are poorly flexible and have a limited possibility to adjust the degree of cooling of the coffee-based beverage. The object of the present invention is to overcome the drawbacks of prior art, by providing an alternative solution for cooling down a coffee-based beverage that is simple and reliable and at the same time allows to adjust the final temperature of the obtained beverage.

These and other objects are achieved with the system and method for preparing a coffeebased beverage as claimed in the appended claims.

Summary of Invention

The system according to the invention comprises a brewing group for preparing a high- temperature coffee-based beverage.

The system according to the invention further comprises a first heat exchanger in which the coffee-based beverage exiting the brewing group releases heat to a flow of cooling fluid, other than water, circulating in a cooling fluid circuit.

The cooling fluid circuit is provided with a pump for circulating the cooling fluid, and, advantageously, the power of said pump can be varied, thereby varying the flow rate of the cooling fluid in the cooling fluid circuit: by adjusting the flow rate of the cooling fluid it is possible to continuously adjust the temperature of the coffee-based beverage at the exit of the heat exchanger and, thus, the temperature at which said beverage is dispensed.

Preferably, the system according to the invention further comprises a second heat exchanger in which the cooling fluid circulating in the cooling fluid circuit releases heat to a stream of water circulating in a water circuit.

Advantageously, the water circuit passing through the second heat exchanger can be the same that feeds water to a boiler and from the latter to the brewing group. In this way, the heat released by the cooling fluid to the water in the second heat exchanger makes it possible to pre-heat the water before this enters the boiler.

Compared to known solutions where heat is released directly by the brewed beverage to the water, the system according to the invention maintains the advantageous possibility of preheating the water used in the brewing group, but it is more flexible thanks to the interposition of the cooling fluid circuit, which makes it possible to introduce a certain number of degrees of freedom (nature of the cooling fluid, flow rate of the cooling fluid, etc.).

Similarly, the method according to the invention comprises a step of reducing the temperature of the coffee-based beverage exiting the brewing group, wherein said beverage releases heat to a flow of cooling fluid, other than water, circulating in a cooling fluid circuit. The method according to the invention further provides that, at this step, the flow rate of cooling fluid used for cooling down the coffee-based beverage is adjusted to obtain the desired temperature of the beverage upon dispensing thereof.

Preferably, the method according to the invention further provides for a step of reducing the temperature of the cooling fluid, wherein said cooling fluid releases heat to the water circulating in a water circuit, thereby simultaneously obtaining a pre-heating of said water. Brief Description of Drawings

Further features and advantages of the invention will become more evident from a detailed description of some preferred embodiments, given by way of non-limiting examples with reference to the annexed drawings, in which:

Fig. 1 schematically shows the hydraulic circuit of the system according to a first embodiment of the invention; Fig. 2 schematically shows the hydraulic circuit of the system according to a second embodiment of the invention.

Description of Embodiments

Figures 1 and 2 schematically show the essential components of the hydraulic circuit of a system for producing coffee-based beverages according to the invention.

Said system can be implemented, for example, in espresso coffee machines, and particularly (though not exclusively), in espresso coffee machines of the fully automatic type.

It will be apparent to the person skilled in the art that such coffee machines may comprise in a manner known per se the desired components necessary to prepare coffee-based beverages (coffee powder storage tanks, or coffee bean storage tanks and related grinderdosers, milk tanks, milk frothing/whipping means and so on).

Such components are not described herein because they are known per se and not strictly necessary to the understanding of the invention.

Referring initially to Figure 1, this shows the hydraulic circuit of a system for preparing coffee-based beverages 100 according to a first embodiment of the invention.

In a manner known per se, said system 100 comprises a brewing group 10, in which a coffeebased beverage is prepared by making a stream of water at a high temperature (about 85 - 95°C) pass through a coffee powder panel.

For this purpose, the system 100 comprises a water circuit 20 fed with cold water coming from a water source 22. Said water source 22 can be either the water main or a dedicated tank.

Along the water circuit 20, upstream of the brewing group 10, there are arranged a pump 24 and a boiler 26.

The boiler 26 makes it possible to increase the water temperature from the initial temperature at the water source 22 (for example, the temperature of the water main, or the ambient temperature) to the temperature desired for brewing the coffee panel in the brewing group 10.

The pump 24 makes it possible to promote the circulation of water from the cold water source 22 to the boiler 26 and from the latter to the brewing group 10. In addition, the pump 24 can be used for increasing the water pressure so that the stream of water passing through the coffee panel in the brewing group 10 has not only a high temperature, but also a high pressure.

Downstream of the brewing group 10, the system comprises an outlet line 30 along which the beverage prepared in said brewing group 10 can flow. The outlet line 30 ends with a dispensing port 32 through which the beverage can be dispensed and served.

According to the invention, along the outlet line 30, upstream of the dispensing port 32, there is arranged a first heat exchanger 40, so that a corresponding section of the outlet line 30 forms a primary side 42 of said heat exchanger.

The secondary side 44 of the first heat exchanger 40 is formed by a corresponding section of a cooling fluid circuit 50 in which a cooling fluid other than water flows.

For example, the cooling fluid may be Glysofor F, a propylene glycol-based coolant widely used in the food industry, or an aqueous solution of Glysofor F.

In the first heat exchanger 40, the coffee-based beverage flowing in the primary side 42 releases heat to the cooling fluid circulating in the secondary side 44 and is thereby cooled down.

The cooling fluid circuit 50 is preferably a closed-loop circuit.

A pump 52 is arranged on the cooling fluid circuit 50. Advantageously, according to the invention, the power of the pump 52 is variable and controllable, whereby, by controlling the power of the pump 52, it is possible to control the flow rate of the cooling fluid in the cooling fluid circuit 50, and especially in the secondary side 44 of the first heat exchanger 40.

Accordingly, by varying the flow rate of the cooling fluid in the first heat exchanger it is possible to continuously control the temperature of the beverage exiting said first heat exchanger 40, and then exiting the dispensing port 32: by increasing the flow rate of the cooling fluid, cooling will be more pronounced and the temperature of the dispensed beverage will be lower; by reducing the flow rate of the cooling fluid, cooling will be less pronounced and the temperature of the dispensed beverage will be higher.

Advantageously, in the shown embodiment, the system 100 comprises a second heat exchanger 60 arranged along the cooling fluid circuit 50, so that a corresponding section of the cooling fluid circuit 50 forms a primary side 62 of said heat exchanger.

The secondary side 64 of the second heat exchanger 40 is formed by a corresponding section of the water circuit 20.

In the second heat exchanger 60, the cooling fluid flowing in the primary side 62 (and having absorbed heat from the coffee-based beverage in the first heat exchanger 40) releases heat to the stream of water circulating in the secondary side 64 and is thereby cooled down.

At the same time, the water circulating in the secondary side 64 absorbs heat, thereby obtaining a pre-heating of the water before this enters the boiler 26.

Compared to a solution in which the coffee-based beverage directly releases heat to the water in a single heat exchanger, the system according to the invention has obvious advantages.

Firstly, at the design stage, it is possible to freely select the cooling fluid that is considered to be most suitable. It is evident that the thermal exchange coefficient plays an essential role in the selection of the cooling fluid. However, other parameters, such as, for example, poor corrosivity, can also be taken into account.

Secondly, and more importantly, during operation the flow rate of the cooling fluid can be freely controlled, by acting onto the pump 52 of the cooling fluid circuit 50. As the pump 24 of the water circuit determines the pressure at which water circulates in the water circuit 20 and the brewing group 10, said pressure could not be controlled as freely, because the operating specifications thereof are essentially imposed by the pressure that the water passing through the coffee powder panel for brewing and preparing the beverage should have. Conversely, the operation of the pump 52 of the cooling fluid circuit does not interact in any way with the brewing group and determines solely the flow rate of the cooling fluid in said circuit.

In conclusion, the system according to the invention proves to be much more flexible than a solution in which the coffee-based beverage directly releases heat to the water in a single heat exchanger.

Referring again to Figure 1, in order for a high-temperature coffee-based beverage to be servable at the dispensing port 32, the outlet line 30 comprises - upstream of the first heat exchanger 40 - a bypass valve 34 which selectively sends the coffee-based beverage either through the first heat exchanger 40 or through a bypass duct 36, which is joined to the outlet line downstream of said first heat exchanger 40: by setting the bypass valve 34 so as to divert the coffee-base beverage through the bypass duct 36, said beverage will not be cooled down and will be dispensed at the dispensing port 32 while having essentially the same temperature that it has at the exit of the brewing group 10.

In the embodiment shown in Figure 1 , the water circuit 20 also has a bypass duct 28 provided with a bypass valve 29.

In said embodiment, the bypass duct 28 of the water circuit is arranged downstream of the boiler 26 and allows to bypass the brewing group 10, so as to make water at a high temperature flow through the outlet line 30. Depending on the position of the bypass valve 34 of the outlet line 30, the water at a high temperature will be able to flow through the bypass duct 36 and from there to the dispensing port 32, or it will be able to flow through the first heat exchanger 40 and be discharged through a drain 38 thanks to the presence of a selector valve 39 arranged between the outlet of said first heat exchanger and the dispensing port 32.

From the above description, it will be apparent to the person skilled in the art that the method according to the invention comprises a step of reducing the temperature of the coffee-based beverage exiting the brewing group, wherein said beverage releases heat to a flow of cooling fluid, other than water, circulating in a cooling fluid circuit.

The method according to the invention further provides that, at this step, the flow rate of the cooling fluid used for cooling down the coffee-based beverage is adjusted to obtain the desired temperature of the beverage upon dispensing.

In particular, the method according to the invention may provide for setting a temperature desired for the coffee-based and accordingly adjusting the flow rate of the cooling fluid in the cooling fluid circuit.

The adjustment of the cooling fluid flow rate is effected by adjusting the power of the pump 52 promoting the circulation of said cooling fluid in the cooling fluid circuit.

It is evident that the system according to the invention may be provided with a control unit in which a table of correlation between the temperature of the dispensed beverage and the flow rate of the cooling fluid in the cooling fluid circuit.

It is also evident that it will be possible to provide for carrying out detections of the actual temperature of the dispensed beverage, checking the accuracy of the data in the above table, and, possibly, taking the necessary corrective actions.

A second preferred embodiment of the invention is shown in Figure 2.

The structure and operation of the hydraulic circuit of the system 100 shown in Figure 2 are essentially identical to those of the hydraulic circuit of the previously described embodiment.

The second embodiment of Figure 2 differs from the previous one in that the water circuit 20 has a bypass duct 28' equipped with bypass valves 29', 29" and arranged upstream of the boiler 26.

The bypass duct 28' of the water circuit 20 thus allows to bypass both the boiler 26 and the brewing group 10, so as to make low-temperature water flow through the outlet line 30.

This stream of water at a low temperature, if passed through the primary side 42 of the first heat exchanger 40, allows to further absorb heat from the cooling fluid circulating in the secondary side 44 of the first heat exchanger 40 and in the cooling fluid circuit 50, thereby lowering the temperature of said cooling fluid.

It will be apparent that the embodiments described herein have been given merely by way of non-limiting examples, and that several modifications and variations within the reach of the person skilled in the art are possible without departing from the scope of the invention as defined by the appended claims.