TECHNICAL FIELD

The present invention relates to a method and a machine for preparing beverages, in particular infusions such as coffee or tea.

BACKGROUND ART

For preparing hot drinks such as coffee or tea, it is already known the use of machines comprising an infusion circuit in which water is heated to a temperature of about 90°C or more and is injected into an infusion chamber housing the infusion product. For example, the infusion product may be in the form of dust or leaves, may be loose or contained in capsules or tablets.

The document EP2083661 relates to a method and a machine for preparing infusions injecting pressurized gas into the infusion chamber simultaneously or before the introduction of water, thus exalting the organoleptic properties of the infusion product. Such method and machine have the disadvantage of requiring the provision of bulky systems for pressurizing the gas (such as compressors) or for supplying the pressurized gas (such as pressurized cylinders) .

DISCLOSURE OF INVENTION

The object of the present invention is to provide a method and a machine for preparing beverages, which overcome the aforesaid problems.

In particular, the object of the present invention is to provide a method and a machine of reduced size for preparing beverages, which nevertheless ensure a high organoleptic quality of the beverages.

The object of the present invention is to provide a method and a machine for preparing beverages as recited in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the accompanying drawings, showing non-limiting embodiments, in which:

- Figure 1 is a schematic view of a first embodiment of the machine according to the present invention;

- Figure 2 is a schematic view of a second embodiment of the machine according to the present invention;

- Figure 3 is a schematic view of a variant of the machine shown in Figure 1; and

- Figure 4 is a schematic view of a variant of the machine shown in Figure 2.

BEST MODE FOR CARRYING OUT THE INVENTION

In Figure 1, the reference number 1 indicates in its entirety a machine for preparing beverages, in particular infusions such as coffee or tea. The machine 1 comprises a unit 2 for feeding the liquid L, in particular water, an infusion chamber 3 for preparing beverages B and an infusion circuit 4.

The feeding unit 2 in turn comprises a water tank 5 and a pump 6. According to a variation not shown, the feeding unit 2 comprises a pump 6 supplying the liquid L directly from a hydraulic network. Advantageously, the pump 6 is a self-priming pump.

In turn, the infusion circuit 4 comprises: a duct 7 connecting in a known way the pump 6 with the infusion chamber 3, and a heat exchanger 8, which is arranged along the duct 7 and heats in a known way a liquid in the infusion circuit 4.

Advantageously, the infusion circuit 4 comprises a source 9 configured to enter a gas G at atmospheric pressure, in particular air at atmospheric pressure, in the infusion circuit 4. Advantageously, the source 9 is arranged in said duct 7 between the feeding unit 2 and the infusion chamber 3. Advantageously, the source 9 enters the gas at atmospheric pressure in the duct 7, thus creating an air cushion that is forced, in use, in the infusion chamber 3 by means of the liquid L supplied by the feeding unit 2.

As shown in Figure 1, in the machine 1 the gas source 9 is a valve, in particular a three-way valve. For example, the valve 9 is a solenoid valve. The valve 9 is arranged in the duct 7 between the pump 6 and the exchanger 8. The valve 9 divides the duct 7 in an initial portion 10 and in a final portion 11. In particular, the initial portion 10 comprises: a portion 10a connecting the water tank 5 with the inlet of the pump 6; a portion 10b connecting the delivery side of the pump 6 with the source 9. In particular, the final portion 11 comprises: a portion 11a connecting the source 9 with the heat exchanger 8; a portion lib connecting the heat exchanger 8 with the infusion chamber 3; a portion 11c at the outlet of the infusion chamber 3 for dispensing the beverage B.

Advantageously, the machine 1 comprises a delivery valve 12 arranged in the portion 11c, downstream of the infusion chamber 3, configured to control the dispensing of the beverage B from the infusion chamber 3.

The initial portion 10 is connected to the pump 6 and, in use, is crossed only by the liquid L. The final portion 11 is crossed, in use, both by the liquid L and by the gas G, as explained in more detail below.

Advantageously, the three-way valve 9 can be selectively arranged in:

- a gas opening position, where it opens the passage of the gas from the outside to the final portion 11 of duct 7 and, simultaneously, closes the passage of the liquid to the final portion 11; a liquid opening position, where it closes the passage of the gas from the outside to the final portion 11 and, simultaneously, opens the passage of the liquid to the final portion 11.

For example, the machine 1 dispenses from the top the beverage B in a cup T arranged at a dispensing position E and, for example, the cup T lies on a horizontal support surface P.

Advantageously, the final portion 11 is inclined, at least in part, with respect to a vertical axis perpendicular to a support surface P. As shown in Figure 1, the portion 11a and part of the portion lib form an inclined segment Hi of the final portion 11. The inclined segment Hi is oriented so that a liquid, flowing inside the inclined segment Hi toward the infusion chamber 3, is pushed against the gravity force. In other words, at least along a part of the final portion 11, the gravity force is contrary to the advancement of a liquid flowing from the source 9 to the infusion chamber 3. This advantageously avoids that in use, the liquid L is mixed to the gas G before reaching the infusion chamber 3. Therefore, thanks to the upward inclination Θ of at least a segment (Hi) of the final portion 11 (i.e. contrary to the gravity force in the crossing direction of the flow) it is avoided that the liquid L can be mixed to the gas G or can enter the infusion chamber 3 before the gas G due to the gravity force. Advantageously, the flow section and the level of inclination Θ of the final portion 11 create a negative force (schematically shown with an arrow Fn in Figure 1) that the liquid L must oppose to reach the infusion chamber 3. Advantageously, the negative force Fn is directly proportional to the gravity force and is given by the relation

Fn = c

in which:

g is the gravity force;

c is a multiplying coefficient function of the size and the inclination Θ of the inclined segment Hi.

Advantageously, the negative force Fn, and consequently the size and the inclination Θ of the inclined segment Hi, is defined based on the amount and the pressure of the gas G to be introduced in the infusion chamber 3 before the arrival of the liquid L. Advantageously, the negative force Fn is defined so as to prevent the liquid L, under the effect of the gravity force g, from entering the infusion chamber 3 before the gas G .

Advantageously, the size and the inclination Θ of the inclined segment Hi are determined so that the amount of gas G to be pressurized is comprised between a minimum of 3 cc and a maximum of 1000 cc.

In Figure 2, 101 indicates a variant of the machine 1. In Figure 2 the components in common with the machine 1 have the same numbering, but in the order of hundreds. In the machine 101 the gas source 109 is a valve arranged downstream of the heat exchanger 108. The valve 109 selectively allows the passage of gas G from the outside to the inside of the infusion circuit 104. In particular, the valve 109 is arranged between the heat exchanger 108 and the infusion chamber 103. For example, the valve 109 is a solenoid valve.

As shown in Figure 2, the initial portion 110 comprises: a portion 110a connecting the water tank 105 with the inlet of the pump 106; a portion 110c connecting the delivery side of the pump 106 with the exchanger 108; a portion llOd connecting the heat exchanger 108 with the source 109.

As shown in Figure 2, the final portion 111 comprises: a portion llld connecting the source 109 with the infusion chamber 103; and a portion 111c at the outlet from the infusion chamber 103 for dispensing the beverage B.

The final portion 111, downstream of the source 109 according to the direction of advancement of the liquid in the circuit 104, is curved. In particular, the portion llld has a U-shaped curve lllu (generally indicated also as gooseneck) , whose concavity faces a horizontal support surface P of the cup T. Advantageously, the curve lllu of the portion llld is such to generate a negative force (schematically shown with an arrow FN in Figure 2) that the liquid L must oppose to reach the infusion chamber 103. Advantageously, in the solution shown in Figure 2, the amount of compressible gas G in the final portion 111 depends on the size (length and cross-section) of the portion perpendicular to the horizontal plane P of the curve lllu, i.e. of portions at least partly inclined with respect to the plane P along which the gravity force J exerts a contrasting action against the liquid flowing in the infusion chamber 103.

Advantageously, the curve lllu prevents the liquid L from flowing, under the effect of the gravity force , in the infusion chamber 103 before and/or simultaneously with the gas G.

According to a variant not shown, the infusion chamber 3 (103) is vertically arranged above the source 9 (109) . In other words, the source 9 (109) is vertically interposed between the infusion chamber 3 (103) and a support surface P. Also in this case, analogously to what described in Figures 1 and 2, the final portion 11 (111) is inclined so as to prevent the liquid from flowing, under the effect of the gravity force g, in the infusion chamber 3 (103) before and/or simultaneously with the gas G.

In Figure 3, the reference number 1' is a variant of the machine 1 shown in Figure 1. In Figure 3, the components in common with the machine 1 are indicated with the same numbers. The machine 1' substantially comprises all the components already described for the machine 1. In addition, the machine 1 includes a pressurized gas G feeding system 15, for example a compressor, feeding the pressurized gas G in the duct 7. In particular, the system 15 feeds the gas G in the inclined segment Hi downstream of the source 9.

In Figure 4, 101' indicates a variant of the machine 101 shown in Figure 2. In Figure 4, the components in common with the machine 101 of Figure 2 have the same numbers. The machine 101' comprises all the components of the machine 101. The machine 101' further comprises a pressurized gas G feeding system 115 in the duct 107. In particular, the system 115 feeds the gas G in the segment lllu, downstream of the source 109.

Advantageously, the pressurized gas G feeding system 15 or 115 is a compressor configured for supplying a gas, for example air, at a pressure of about 2 bar. Advantageously, the compressor 15 or 115 is small-sized.

According to a variant not shown, and in addition to or instead of the delivery valve 12 (112), the final portion 11 (111) of the duct 7 (107) (preferably close to the infusion chamber 3, 103) has means configured to determine the flow and the pressure of the gas G and/or the beverage B in the duct 7 (107) . For example, the duct 7 (107) may comprise bottlenecks or equivalent elements to increase or decrease the pressure of the gas and/or of the beverage B in the duct 7 (107) .

In use, when the machine 1 (101) is off, the infusion circuit 4 (104) is filled with gas G, in particular air, at atmospheric pressure. The heat exchanger 8 (108) is activated in order to heat the liquids flowing inside the infusion circuit 4 (104) upstream of the infusion chamber 3

(103) .

During a dispensing cycle for preparing a beverage B, starting from the disabled machine 1 (101) in which the infusion circuit 4 (104) is already filled with gas G at atmospheric pressure, the gas source 9 (109), e.g. the three-way valve, is disposed in the liquid opening position to allow the flowing of the liquid L in the infusion circuit 4 (104) and to prevent, at the same time, the outflow of the gas G from the circuit through the gas source 9 (109) .

Therefore, the feeding unit 2 (102) is activated to push the gas G, already present in the infusion circuit 4

(104) , in the infusion chamber 3 (103) . The G gas enters the infusion chamber 3 (103) before the liquid L.

In this way, the gas G in the infusion circuit 4 (104) is partially pressurised by the liquid L. Therefore, the partially pressurised gas G is introduced in the infusion chamber 3 (103) .

After a set contact time of the infusion product with the liquid L and the gas G, the delivery valve 12 (112) is opened to allow the outflow of the beverage B from the infusion chamber 3 (103) and its delivery in a cup T, i.e. a cup of coffee.

After dispensing the beverage B, the infusion circuit 4 (104) is emptied to fill again the infusion circuit 4 (104) with gas G at atmospheric pressure. Subsequently, the above steps may be repeated for preparing another beverage B.

In the machine 1 for emptying the infusion circuit 4, the source 9, i.e. the three-way valve 9, is arranged in the gas opening position so as to connect the inside of the infusion circuit 4 with the external environment. During the process of emptying the infusion circuit 4, the liquid and the gas possibly remained in the infusion circuit 4 are pushed out by the pressure generated in the infusion circuit 4 by the heating due to the heat exchanger of the liquid L. In other words, in the machine 1 the infusion circuit 4 is emptied thanks to the pressure developed in the infusion circuit 4 due to the transformation of the residual water contained in the heat exchanger 8, which, once heated up, turns into steam.

On the other hand, in the machine 101 the infusion circuit 104 is emptied by the gravity force, following the delivery of the beverage B. In particular, in the case shown in Figure 2, the emptying occurs through the three- way valve 109, which, when arranged in the gas opening position, enables the emptying by gravity of the liquid L (the liquid L contained in the vertical portion of the curve lllu) and, at the same time, enables the gas G at atmospheric pressure to flow in the infusion circuit 104.

Being the final portion 11 (111) of the machine 1 (101) open both upstream, through the three-way valve 9 (109), and downstream, through Hi and lib (lllu and Hid), 3 (103), 11c (111c) and 12 (112), during and after the delivery, the water exits from the circuit 11 (111) through the valve 9 (109) and through the infusion chamber 3 (103) and the air takes its place. It is thus ensured that the final portion 11 (111) is completely full of gas G and free of liquid L after having prepared a beverage B and before starting preparing the next beverage B.

Advantageously, the amount of gas G supplied to the infusion circuit 4 (104) is determined by the position of the gas source 9 (109) with respect to the infusion chamber 3 (103); and/or by the extension in the practicable forward direction of the gas G in the duct 7 (107) without meeting any obstacle (closing valves or the like) ; and/or by the size of the flow section of the duct 7 (107) .

Advantageously, the pressure of the gas G supplied to the infusion chamber 3 (103) depends on the shape, length and size of the final portion 11 (111) of the duct 7 (107) .

The use of the machines 1' and 101' is similar to the use of the previously described machines 1 and 101. Beside what already described, the machines 1 and 101 provide the introduction of an already compressed gas G in the final portion 11 or 111. This increases the aeration capacity of coffee for preparing beverages B, while maintaining the reduced overall size of the machine 1 or 101.

The machines 1, 101, 1', 101' of the aforesaid type have the advantage of ensuring an aeration of the infusion product by means of pressurized gas to obtain a beverage B whose organoleptic qualities are better than those of the beverages prepared with traditional machines.

Moreover, the machine 1 (101) of the aforesaid type has the advantage of having a simple and inexpensive structure to manufacture.

Furthermore, the method and the machine 1 (101) of the aforesaid type avoid the use of any equipment for supplying the pressurized gas, such as air compressors or cylinders. This considerably reduces the overall size of a machine for preparing beverages provided with this equipment, together with a considerable cost reduction. For example, the aforesaid machine 1 (101) and method may also have a domestic use, while the machines of known type comprising the equipment for gas pressurization may be used only as a bench machines, namely for a professional use.