DRINK"

FIELD OF THE INVENTION

The present invention concerns a coffee pot to obtain a coffee drink.

In particular, the present invention concerns a coffee pot to obtain a coffee drink or other similar or comparable drinks, obtained using coffee substitutes such as barley or suchlike.

The coffee pot according to the present invention can be used in the home and/or in a bar and/or in communities or any other situation, provided there is a controlled source of heat present, to obtain the coffee drink with characteristics similar and/or identical to those obtainable with automatic or semiautomatic machines found in bars.

The present invention also concerns a method to obtain the coffee drink or suchlike.

BACKGROUND OF THE INVENTION

It is known to use coffee pots to obtain a coffee drink, which allow to extract the essence of the coffee to obtain the coffee drink by the inverse percolation of boiling water through a desired quantity of coffee powder.

Hereafter in the description, we will always and exclusively refer to coffee as the starting product, including in this term all possible substitutes or mixtures thereof, while we will refer to the coffee drink including also all the other drinks obtainable with the same device.

One factor commonly observed by consumers, connoisseurs and aficionados of coffee drinks, to judge the quality of the coffee drinks themselves when served, is the presence of froth, that is, a frothy phase on the top of the liquid phase in the cup.

In Italy, this creamy froth is recognized and called, by experts and in everyday parlance, "crema caffe", hereafter indicated in English only as froth.

Within the field of devices for domestic use to obtain a coffee drink, a coffee pot is known which has a lower body into which water is introduced, an intermediate body suitable to contain coffee powder so that the boiling water can pass through it, and an upper body where the coffee drink is positioned after the boiling water has passed through the mass of coffee powder.

In known coffee pots, examples of which are described in documents WO-A- 2010/007592 and EP -A- 1.093.746, the steam generated in the lower body pushes the water through a pipe, forcing it to percolate in an inverse direction (hereafter we will use only the terms percolate-percolation even if it is the inverse type) through the coffee powder.

These known coffee pots are not able to control the percolation action in the desired manner, nor are they able to generate froth.

To obtain a certain control, extensions are provided in the path of the water, or systems to create pressures in the water, but these do not obtain a correct control of the passage of the water through the coffee powder, for a plurality of reasons.

In fact, known coffee pots obtain a coffee drink that has neither the intensity, nor the aroma, nor the froth of coffee drinks that are obtained with automatic or semiautomatic machines used in bars for example.

An example of such known coffee pots is described for example in document WO-A-2006/018858, in which the coffee pot comprises a boiler body provided with a bottom wall, a container to contain the coffee drink obtained and a cup- shaped body.

The cup-shaped body can be inserted in the boiler body, in an upturned position, to dispose its open end resting on the bottom wall of the boiler body.

The cup-shaped body is also provided with an elastic bottom.

The coffee pot also comprises a filter interposed between the boiler body and the container that collects the coffee drink, and a contact element positioned in contact with the elastic bottom of the cup-shaped body.

The cup-shaped body is filled with water and an infusion material and is subsequently inserted into the boiler body, to position its open end resting against the bottom wall of the boiler body.

Subsequently, the filter is associated with the boiler body and the container that collects the coffee drink is put to close the boiler body.

The reciprocal contact between the contact element of the filter and the elastic bottom of the cup-shaped body prevents, under normal conditions, the water and the infusion material from leaking.

According to an alternative provided in WO-A-2006/018858, instead of being inserted in the shaped body, the infusion material can be disposed in a cavity defined by the filter.

Heating the boiler body generates an increase in the pressure of the water contained in the shaped body, which causes the cup-shaped body to rise and the drink to come out. The drink can subsequently pass through an elongated portion provided between the boiler body and the collection container.

These solutions are not only complex to make and require particular attention from the operator every time the coffee pot is filled for each new use, they also produce a low-quality coffee because of the limited possibility of controlling the stream and temperatures of the coffee drink that is made to pass from the boiler body to the collection container.

There is therefore a need to perfect a coffee pot both to obtain the coffee drink and to realize an operating method to obtain a coffee drink to overcome at least one of the disadvantages of the state of the art.

In particular, one purpose of the present invention is to obtain a coffee pot and the corresponding operating method, which allow to obtain a coffee drink of a better quality than those obtainable in known coffee pots, given the same physical and qualitative characteristics of the coffee used as starting material.

Moreover, another purpose of the present invention is to obtain a coffee pot to make coffee drinks, and the corresponding operating method, which guarantee the best transfer, during percolation, of the essences and aroma typical of coffee from the latter to the water, allowing a homogeneous and controlled distribution of the water through the mass of coffee.

Another purpose of the present invention is to obtain a coffee pot to make coffee drinks and to perfect the corresponding operating method which, given the same result, allows to use a smaller quantity of coffee powder compared with known coffee pots to obtain a coffee drink of at least equal quality.

Another purpose is to obtain a coffee drink with a coffee pot which is of a quality near to if not equal to that obtainable with espresso coffee machines used in bars or suchlike.

Another purpose of the present invention is to obtain a coffee pot and the corresponding operating method to obtain coffee drinks, suitable for the purposes indicated above, which are simple, intuitive and practical for operators. Another purpose of the present invention is to obtain a coffee pot and the corresponding operating method to make coffee drinks, which allow to obtain a coffee drink of optimum quality irrespective of the ability and skill of the operator using it.

Another purpose of the present invention is to obtain a coffee pot and the corresponding operating method to make coffee drinks, which allow to obtain the coffee drink with optimum organoleptic properties both using loose coffee powder and also coffee powder in pods.

Furthermore, another purpose of the present invention is to obtain a coffee pot that is compact, of reduced size and not bulky.

Another purpose of the present invention is to obtain a coffee pot and the corresponding operating method to make coffee drinks, which are safe and reliable.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims, while the dependent claims describe other characteristics of the invention or variant embodiments to the main inventive idea.

In accordance with the above purposes, a coffee pot is provided that comprises at least a compartment to contain water necessary to obtain the coffee drink, at least a container to contain coffee powder, put in fluidic connection with the compartment, and at least an upper body, or receptacle, to collect the coffee drink obtained from percolating water in the compartment through the coffee powder.

In particular the receptacle to collect the coffee drink is fluidically connected to the compartment and to the container through a passage provided between the container and the receptacle.

In accordance with one aspect of the present invention, the coffee pot comprises at least an elastic energy accumulation member configured to accumulate pressure or elastic energy from the supply of heat energy, and at least a thrust device associated with the elastic energy accumulation member and configured to thrust the water contained in the compartment through the container, and therefore through the coffee powder contained in the latter and obtain the coffee drink obtained in the upper body or receptacle.

In particular, the thrust action of the water is generated by the pressure energy accumulated by the elastic energy accumulation member.

In accordance with another aspect of the present invention, the coffee pot also comprises a valve associated with the passage provided between the container and the receptacle. The valve comprises a fixed unit, an opening/closing unit associated with the fixed unit and configured to selectively open/close the passage, and a sensitive member associated with the opening/closing unit and configured to detect the temperature of the coffee drink in the compartment and to open the opening/closing unit when a predefined temperature of the coffee drink is reached in the compartment.

According to a variant, the elastic energy accumulation member is immersed in a mediator element, located between an external container, which cooperates directly with the heat source, and the elastic energy accumulation member.

The mediator element transmits the heat to the elastic energy accumulation member.

According to a variant, the elastic energy accumulation member is hit directly by the heat generated by the external heat source.

The elastic energy accumulation member has the characteristic that it expands, in a desired and controlled manner depending on the temperature that it reaches when subjected to a source of heat, so that it is able to act on the thrust device.

The thrust device works on the volume of the compartment, therefore acting on the water present therein. Before being transferred by the thrust device, the water contained in the compartment is heated to the desired temperature by the source of heat to which it has been subjected, possibly by transferring heat from the mediator element and/or the elastic member.

The water is therefore thrust to pass through the mass of coffee powder arriving in the receptacle, already in the form of a coffee drink.

The valve associated with the passage provided between the container and the receptacle prevents the passage of the coffee drink from the compartment to the receptacle until the water has reached a predefined temperature, established by the specific calibration of the sensitive member of the valve. To this end, in accordance with possible solutions, at least in the closed valve condition, that is, which prevents the coffee drink passing through the passage, the sensitive member is positioned at least partly in the compartment or in the container for the coffee powder, in order to detect the temperature of the water that has passed through the coffee powder and that is put under pressure by the thrust device.

According to a variant of the invention, the elastic energy accumulation member comprises at least a containing body configured to contain a substance expandable through heat effect in a controlled manner and an elastic device configured to accumulate in a restorable manner the energy supplied to it by the expansion of the expandable substance.

In accordance with one aspect of the present invention, a method to obtain the coffee drink is provided that comprises, in a desired sequence:

- filling the compartment with a metered quantity of water,

- heating said metered quantity of water,

- filling the container with a metered quantity of coffee powder,

- heating at least the elastic energy accumulation member, and accumulating in said elastic energy accumulation member the heat energy in the form of pressure or elastic energy,

- transferring energy from the elastic energy accumulation member to the thrust device,

- making the thrust device act on the water present in the compartment,

- making the water from the compartment percolate through the coffee powder, thus generating the coffee drink,

- keeping the coffee drink in the compartment and/or in the container of the coffee powder until a desired temperature is reached,

- said desired temperature opening the adjustable valve and making the coffee drink exit from the compartment and/or from the container and making it reach the receptacle to contain it therein, the opening of the valve being provided by detecting the temperature of the coffee drink in the compartment and, when a predefined temperature of the coffee drink in the compartment has been reached, and by activating an opening/closing unit associated with the passage, to allow the opening of the passage and therefore allow the coffee drink to pass through it. BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics of the present invention will become apparent from the following description of some embodiments, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a cross section of a coffee pot in a first operating condition, in accordance with embodiments described here;

- fig. 2 is a cross section of the coffee pot in fig. 1 in a second operating condition;

- fig. 3 is a cross section of the coffee pot in fig. 1 in a third operating condition; - fig. 4 is a cross section of a coffee pot, in accordance with other embodiments described here;

- fig. 5 is an enlarged cross section of a detail of the coffee pot in fig. 1 or fig. 2;

- fig. 6 is an enlarged cross section of a detail of the coffee pot in fig. 3;

- fig. 7 shows a possible variant of fig. 1.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can conveniently be incorporated into other embodiments without further clarifications.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

Fig. 1 is used to describe example embodiments of a coffee pot 10 to obtain a coffee drink.

According to variant embodiments described using figs. 1-4, the coffee pot 10 can comprise an external container 11 configured to receive and transfer heat.

The external container 11 is also configured to support and protect other elements of the coffee pot 10.

Advantageously, the external container 11 can comprise a base 46 positionable in contact with a source of heat of a known type such as for example a gas, electric or induction ring, or a stove.

Alternatively, or additionally, the coffee pot 10 can also be heated by a stream of hot air, external or also directly on its internal elements.

The coffee pot 10 comprises a compartment 12 to contain water, at least one container 14 to contain coffee powder associable with the compartment 12 and located in fluidic communication with the latter, and at least one receptacle 16 to collect the coffee drink obtained from percolating water, contained in the compartment 12, through the coffee powder contained in the container 14.

The container 14 is positioned at least partly inside the compartment 12 and is selectively removable from it to allow, for example, operations to clean or fill the compartment 12 with water.

The container 14 is configured to replaceably contain coffee powder inside it, and can comprise a filter 40 which, during use, closes the container 14 and prevents or at least limits the leakage of coffee powder. The filter 40 can be defined by a plate provided with a plurality of holes configured to allow the water to pass and to prevent the coffee powder from passing through them.

According to possible embodiments, the container 14 is suitable for the introduction of coffee powder in the desired quantity, or of pods.

The compartment 12 is configured to contain the quantity of water needed for the expected quantities of coffee drink.

The receptacle 16 is configured to collect, and at least temporarily preserve, the coffee drink obtained by percolating the water through the coffee powder.

Furthermore, according to one aspect of the present invention, the coffee pot 10 comprises at least one elastic energy accumulation member 18, at least one thrust device 20 and at least one valve 22.

In addition, the coffee pot 10 comprises at least one controlled expansion chamber 15 associated with the compartment 12 and a free expansion chamber 24 fluidically connected to the controlled expansion chamber 15.

For the connection, during use, of the elements of the coffee pot 10, the external container 11 can comprise at least one connection element 48.

The external container 11 is provided with a compartment 49 in which the connection element 48 is at least partly positioned, and the compartment 12 to contain the water.

According to variant embodiments, the connection element 48 can be configured to attach the elastic energy accumulation member 18 and/or the compartment 12 to the external container 11.

Furthermore, the connection element 48 can be configured to obtain a thermal bridge between the external container 11 and at least the elastic energy accumulation member 18 and/or the compartment 12. According to variant embodiments, the connection element 48 can allow the practical removal of both the compartment 12 and the elastic energy accumulation member 18.

According to one embodiment, the compartment 12 and the elastic energy accumulation member 18 are connected non-removably with each other.

According to variant embodiments, the compartment 12 and the elastic energy accumulation member 18 can be associated with each other removably.

The compartment 12 comprises an aperture 26 configured to put the compartment 12 in communication with the container 14 and the controlled expansion chamber 15.

The aperture 26 is configured so as to allow the introduction of water into the compartment 12, which is filled with a desired quantity of water.

To this purpose, the compartment 12 can comprise a level indicator to signal to the operator when a suitable quantity of water has been introduced.

According to the solution shown in figs. 1-4, the container 14 of the coffee powder is disposed at least partly in the compartment 12, inserting it through the aperture 26.

According to some solutions, the edges of the compartment 12 which define the aperture 26 act as a support for the container 14 of the coffee powder.

According to variant embodiments, the compartment 12 can preferably be made in separable parts, so that they can easily be cleaned.

The controlled expansion chamber 15 can be provided in the compartment 12, above the container 14 of the coffee powder.

The controlled expansion chamber 15 is fluidically connected to the receptacle 16 by means of the free expansion chamber 24.

The coffee pot 10 can comprise a passage 28 between the controlled expansion chamber 15 and the free expansion chamber 24, which can be selectively opened and closed by driving the valve 22.

In particular, the free expansion chamber 24, facing toward the receptacle 16, is fluidically and selectively connected to the controlled expansion chamber 15 by means of said passage 28.

The coffee pot 10 can comprise a space 52 between the external container 11 and at least the elastic energy accumulation member 18. The external container 11 is configured to contain in the space 52 at least one mediator element 44, such as one or more fluids, or one or more gels, or one or more semisolid or solid materials, one or more gases, or a mixture of all or some of these, able to convey a heat flow, by indirect heat transfer, from the external container 11 to at least the elastic energy accumulation member 18 and/or the compartment 12.

According to a possible solution, the mediator element 44 comprises water, replaceable on each occasion by an operator every time the coffee pot 10 is used.

According to a variant, the mediator element 44 is kept in the external container 11, without requiring replacement, for the whole working life of the coffee pot 10.

In the example case shown in the attached drawings, the elastic energy accumulation member 18 comprises a containing body 30 in which an expandable substance 34 is disposed.

The mediator element 44 allows a gradual transmission of the heat to the expandable substance 34 contained in the containing body 30 and is configured to not raise the pressure inside the external container 11, or to allow it to rise in a limited and controlled manner. In particular, the heat supplied to the external container 11 is transferred, by the mediator element 44, to the elastic energy accumulation member 18 and to the water contained in the compartment 12.

The heat energy supplied to the elastic energy accumulation member 18 is converted by the latter into pressure or elastic energy, while the heat energy supplied to the compartment 12 allows to heat the water to allow the subsequent percolation through the coffee powder.

Advantageously, the compartment 12 and the elastic energy accumulation member 18 can be associated so as to exchange heat energy.

According to variant embodiments, the expandable substance 34 has the capacity to expand in a controlled manner due to the effect of heating, depending on the temperature reached in the containing body 30.

According to variant embodiments, the expandable substance 34 can comprise one or more gel or liquid materials, or semisolid or solid, one or more gases, or a mixture of all or some of these.

In turn, due to the effect of the expansion of the expandable substance 34, the containing body 30 is configured to expand in a desired and reversible manner due to the presence of at least one elastic device 32, functioning as an energy store.

According to another solution (figs. 1-3) the elastic device 32 is integrated in the containing body 30, or at least a part of the latter is elastically deformable to accumulate pressure energy. In particular, it can be provided that, due to the expansion of the expandable substance 34, the containing body 30 is configured to expand, deforming elastically.

In fact, the elastic device 32 is associated with the containing body 30 and is configured to absorb the energy supplied by the expansion of the expandable substance 34.

To this purpose, the containing body 30 comprises at least a fixed part and at least a mobile part, configured to transfer energy to the elastic device 32.

Depending on the heat that hits it, the expandable substance 34 expands, thus contrasting the elastic device 32 to which the energy elastically accumulated in it is transferred.

The expandable substance 34 can be chosen so that it expands in a desired manner at a predefined temperature above which a further expansion of the expandable substance 34 is not obtained.

Consequently, if the coffee pot 10 is subjected to uncontrolled temperatures, even for long times, breakages or even explosions can be avoided.

According to possible solutions, the containing body 30 can be provided, on at least one surface that faces the expandable substance 34 during use, with fins provided to increase the heat exchange surface with the expandable substance 34 and allow a uniform heating of the latter. The presence of the fins allows to optimize the heating times of the coffee pot 10 and ensure a correct functioning thereof.

According to variant embodiments, the elastic device 32 can be a separate element from the containing body 30 and can comprise springs, in this case shown in fig. 4 cup springs, or alternatively helical springs or other similar elements with elastic constants able to resist the pressure reached by the containing body 30. As well as acting on the elastic device 32, as it expands the expandable substance 34 also acts on the thrust device 20, as can be understood from the sequence shown in figs. 1 and 2.

In fact, at least one surface portion of the thrust device 20 is located in or in communication with the containing body 30, to be driven by the thrust exerted by the expansion of the expandable substance 34.

Therefore, the expandable substance 34 on the one hand loads the elastic device 32 and on the other hand acts on the thrust device 20.

According to variant embodiments, the thrust device 20 can comprise a piston 36 and an elastic element 38.

The piston 36 is disposed sliding in the compartment 12 and when activated determines the passage of the water from the latter to the receptacle 16.

Furthermore, at least a part of the piston 36 is positioned in the containing body 30, in contact with the expandable substance 34, to receive a thrust from the latter.

When the expandable substance 34 cools, the elastic device 32 returns the containing body 30 to the initial volume so that, together with the combination of the elastic element 38, the thrust device 20 also returns to the initial position.

The elastic element 38 is also configured to contrast the advance of the piston 36 in the compartment 12 in a desired manner.

In addition, the elastic element 38 serves to contrast a movement of the piston 36 when the expandable substance 34 is first heated, and hence to prevent the still cold water from entering into the coffee powder.

Furthermore, the elastic element 38 is configured to make the water percolate in the coffee powder only when a desired pressure is reached.

According to variant embodiments, the elastic element 38 can preferably be disposed between the piston 36 and an upper edge of the compartment 12 which defines the aperture 26, so as to reduce the bulk and to be compressed when it receives the thrust from the elastic energy accumulation member 18.

According to other variant embodiments, shown by dashes in fig. 1, the elastic element 38 can be disposed inside the containing body 30, connected between the piston 36 and the bottom of the containing body 30, so as to be extended when it receives the thrust from the elastic energy accumulation member 18 and hidden from sight of a user.

According to other variant embodiments, the elastic element 38 could alternatively be disposed between the piston 36 and the containing body 30.

According to variant embodiments, the elastic element 38 can comprise at least a spring, such as for example a helical spring, or similar and comparable elements.

To obtain the coffee drink it is advantageous that the temperature at which the valve 22 is driven, and hence the temperature of the coffee drink in the controlled expansion chamber 15, has reached the desired temperature which, by way of example, can be comprised between 88°C and 96°C, advantageously around 92°C.

Moreover, the pressure at which the water passes through the coffee powder is advantageously comprised, by way of example, between 8xl0 ⁵ Pa and 10x10 ^s Pa, advantageously around 9xl0 ⁵ Pa.

Making the coffee drink in this way allows to extract the aromatic oils of the coffee powder more effectively and better, thus obtaining the desired froth.

The coffee drink that arrives in the controlled expansion chamber 15, due to the thrust action of the thrust device 20, on the one hand absorbs the pressurized air present therein, generating a first quantity of froth, and on the other hand begins to interact with the valve 22, heating it.

The valve 22 is associated with the free expansion chamber 24 and is selectively drivable by the coffee drink, when the latter reaches a desired temperature.

The receptacle 16 defines a chamber to contain the coffee drink, and its sizes are suitable to contain at least a quantity of coffee drink equal to the nominal quantity of the coffee pot 10.

The receptacle 16 can comprise a shield 74, associated with the free expansion chamber 24, and configured to prevent splashes of coffee drink in unwanted zones and at the same time to make the coffee drink collaborate better with the air.

Preferably the receptacle 16 comprises at least a spout 42 for pouring the coffee drink.

To obtain the coffee drink, it is then provided to supply heat energy to the coffee pot 10, heating at least the elastic energy accumulation member 18 and taking the expandable substance 34 to increase its volume. The increased volume of the expandable substance 34 consequently produces an increase in pressure on the walls of the containing body 30.

This pressure loads with energy at least the elastic device 32, which is associated with the containing body 30.

Furthermore, the pressure exerted by the expandable substance 34 acts on the piston 36 of the thrust device 20 in the direction of the container 14.

The movement of the piston 36 leads to a compression of the elastic element 38 and simultaneously moves the water contained in the compartment 12 toward the coffee powder inside the container 14.

According to variant embodiments described using figs. 1, 2, 4 and 5, the first operating condition of the valve 22, that is, the closure of the passage of the coffee drink from the controlled expansion chamber 15 to the free expansion chamber 24, is advantageously maintained until the coffee drink contained in the controlled expansion chamber 15 has reached the desired temperature.

The valve 22 can comprise a fixed unit 22a and an opening/closing unit 22b.

The fixed unit 22a is attached solidly to the receptacle 16 while the opening/closing unit 22b is mobile with respect to the fixed unit 22a to determine the opening/closing of the passage 28.

The opening/closing unit 22b is configured to be mobile axially and slide on the fixed unit 22a, so as to move to a first operating condition in which it closes the passage 28, and a second operating condition in which it opens the passage 28, allowing the coffee drink to reach the free expansion chamber 24.

The opening/closing unit 22b of the valve 22 comprises at least a sensitive member 54 able to detect the desired temperature of the coffee drink at which to activate the valve 22. This frees the passage 28 between the controlled expansion chamber 15 and the free expansion chamber 24, taking the valve 22 to the second operating condition.

According to variant embodiments, the sensitive member 54 can cooperate at least partly with the controlled expansion chamber 15.

In particular, it can be provided that the sensitive member 54 is positioned, at least partly, in the controlled expansion chamber 15 at least when the opening/closing unit 22b is in its first operating condition.

The sensitive member 54 can comprise a collection chamber 58 configured to contain expanding material 60.

According to variant embodiments, the expanding material 60 can comprise one or more gel or liquid materials, or semisolid or solid, one or more gases, or a mixture of all or some of these. The expanding material 60 is the type suitable to expand volumetrically as its temperature increases.

One example of an expanding material 60 and/or expandable substance 34 is paraffin, preferably the refined type.

Furthermore, the opening/closing unit 22b can comprise an actuator 62, a shuttle 64, clamping elements 66 and an elastic unit 68.

According to variant embodiments, the actuator 62 can be associated with the sensitive member 54 and the shuttle 64. In particular, it can be provided that the actuator 62 is inserted slidingly into the collection chamber 58. The sliding of the actuator 62 is determined by the expansion of the expanding material 60 in the collection chamber 58.

The shuttle 64 is configured to load and position the valve 22 in a desired position to obtain the coffee drink.

According to variant embodiments described using fig. 5, to make the coffee drink, the valve 22 is in a first operating condition in which the opening/closing unit 22b cannot move with respect to the fixed unit 22a due to the clamping elements 66 provided between the fixed unit 22a and the opening/closing unit 22b.

Furthermore, the elastic unit 68 is configured to keep both the shuttle 64 in contact with the actuator 62 and also the actuator 62, in turn, in contact with the expanding material 60.

Additionally, the elastic unit 68 is also configured to allow the opening/closing unit 22b to slide on the fixed unit 22a.

According to variant embodiments described using figs. 3 and 6, when the sensitive member 54 detects the desired temperature, it activates the actuator 62 which in turn acts on the shuttle 64, freeing the opening/closing unit 22b from the fixed unit 22a and thus allowing the valve 22 to free the passage 28.

The shuttle 64 can comprise a hollow 70 configured to free the clamping elements 66.

The opening/closing unit 22b comprises an abutment element 72 configured to determine the maximum travel of the valve 22 in its second operating condition.

Once the coffee drink has been obtained, it is possible to act on the shuttle 64 to reload the elastic unit 68, freeing the clamping elements 66 from the hollow 70 and constraining them once again between the opening/closing unit 22b and the fixed unit 22a.

We will now describe in detail a possible functioning of the valve 22 during the normal use of the coffee pot 10.

In its inactive condition, the valve 22 is open, leaving the passage 28 open, and the opening/closing unit 22b is thrust upward by a first elastic element 69 of the elastic unit 68 and held in an end-of-travel position by the abutment element 72. The shuttle 64 remains in a high position because the clamping elements 66 emerge from seatings 67 made in the fixed unit 22a toward the shuttle 64, and are inserted in the hollows 70 of the shuttle 64, creating a stop tooth which prevents the shuttle 64 from re-entering under the action of a second elastic element 71 of the elastic unit 68 provided between the shuttle 64 and a pin 73, and/or a possible striker element 75 associated with the latter, and both integrated with the fixed unit 22b.

The actuator 62 of the valve 22 is in a retracted position, i.e. in a low or non- excited inactive position. This position is also ensured by a third elastic element 76 of the elastic unit 68, provided between the actuator 62 and the pin 73, and/or the possible striker element 75.

Before starting to heat the coffee pot 10, the valve 22 must be closed, thrusting the opening/closing unit 22b manually downward in order to overcome the thrust of the first elastic element 69. In this way, the opening/closing unit 22b slides inside the fixed unit 22a to take the clamping elements 66 into correspondence with the seatings 67 of the fixed unit 22a. When the clamping elements 66 are in correspondence with the seatings 67, they are inserted in the latter due to the thrust exerted by the particular conformation of the hollows 70 of the shuttle 64. At this point the shuttle 64 is free to move, and under the action of the second elastic element 71 is thrust downward until it stops against a thrust plane 77 provided in the actuator 62. In this position, due to the thrust exerted by the first elastic element 69 on the opening/closing unit 22b, the clamping elements 66 are inserted into the seatings 67, determining a stop tooth which keeps the whole opening/closing unit 22b in this position. In this condition, the sensitive member 54 is inserted in the passage 28 and, with a toroid packing 79 present therein, hermetically closes the passage 28, thus creating the controlled expansion chamber 15. In this position the sensitive member 54 is influenced by the temperature of the elements present in the controlled expansion chamber 15.

At this point the valve 22 is closed and the coffee pot 10, previously loaded with the various elements, is ready for use.

The coffee pot 10 is put on a heat source. By means of the mediator element 44, the heat heats both the expandable substance 34 and also the water contained in the compartment 12. At a predefined temperature the expandable substance 34 begins to expand, moving the piston 36 which thrusts upward the water of the compartment 12, by now hot, for example at about 85°- 88°C, beginning to create the coffee drink. The air contained in the controlled expansion chamber 15 is compressed due to the pressure created by the piston 36 and the coffee drink that is generated enters into contact and transfers heat to the sensitive member 54.

The coffee powder is immersed in the hot, pressurized water for a predetermined time and, in this determinate physical combination, releases the maximum amount of essential oils. When the coffee drink in the controlled expansion chamber 15 reaches a temperature such as to command the opening of the valve 22, the water is made to percolate through the coffee powder so that the essential oils, which had started to spread in the infusion liquid, are completely extracted. When the valve 22 is opened, the coffee drink is conveyed toward the receptacle 16 due to the thrust of the piston 36.

The expanding material 60 contained in the collection chamber 58, sensitive to heat as it is, expands, making the actuator 62 move and slide upward.

The shuttle 64, held in contact with the thrust plane 77 of the actuator 62 by the thrust exerted by the second elastic element 71, faithfully follows the movement of the actuator 62. The hollow 70 is positioned so that the opening/closing unit 22b is freed, opening the passage 28, for example at a temperature of 92°C.

The opening/closing unit 22b is freed, opening the passage 28, when the hollow 70 of the shuttle 64 is aligned with a through compartment 92 provided in the opening/closing unit 22b and in which the clamping element 66 is partly housed. At that precise moment the clamping elements 66 emerge from the seatings 67 of the fixed unit 22a and enter into the hollow 70 of the shuttle 64. This in practice frees the opening/closing unit 22b which is raised, leaving the passage 28 free and thus allowing the coffee infusion to emerge, through the free expansion chamber 24, into the receptacle 16. The upward travel of the opening/closing unit 22b continues under the action of the first elastic element 69 and is limited by the abutment element 72. At this point the valve 22 is completely open with the actuator 62 in a high, excited position.

Once the coffee infusion has emerged into the receptacle 16, and the coffee pot 10 is removed from the source of heat, a step of cooling the coffee pot 10, and consequently the whole valve unit 22, begins.

The expanding material 60 is sensitive to temperature, and as it cools it contracts, allowing the actuator 62 to slide downward to return to its initial inactive position. This movement is facilitated by the third elastic element 76 which exerts a downward thrust. On the contrary, together with the opening/closing unit 22b, the shuttle 64 remains clamped in a high position, under the action of the clamping elements 66, as already described above, leaving the valve 22 open and ready to be reloaded to start the cycle again.

For this reason, the valve 22 can be open at any moment, by lifting the shuttle 64 manually.

In this way the coffee pot 10 can be re-used to obtain coffee drinks.

For the safety reasons cited above, the external container 11 can comprise at least one hole 50, or vent, or safety valve, which intervenes at a predetermined pressure, so that possible gas or steam generated by the mediator element 44 can escape.

The coffee pot 10 can also comprise a lid 78 and a handle 80.

It is clear that modifications and/or additions of parts may be made to the coffee pot 10 and the corresponding method as described heretofore, without departing from the field and scope of the present invention.

According to fig. 7, for example, another variant is shown of the elastic energy accumulation member 18, which comprises a containing body 30 inserted in the external container 11 and associated with the compartment 12 that contains the water. The containing body 30 is substantially rigid and filled with the expandable substance 34.

The elastic device 32, provided to accumulate elastic energy deriving from the expansion of the expandable substance 34, is inserted in the containing body 30. In particular, the elastic device 32 in this case comprises a striker plate 82, inserted mobile linearly in a compartment 83 made in the containing body 30. The striker plate 82 is provided with a first surface, facing toward the expandable substance 34 during use, to receive pressure energy from the latter, and with a second surface, opposite the first surface, defining part of said compartment 83. Elastic elements 84 are inserted in the compartment 83, and are suitable to absorb the expansion energy of the expandable substance 34.

The elastic elements 84 in this case can be compression springs, for example cup springs, provided to absorb the energy transferred by the movement of the striker plate 82.

The containing body 30 can be provided with end-of-travel elements suitable to limit the travel of the striker plate 82 in the containing body 30, for example to pre-load the elastic elements 84.

The piston 36 is at least partly inserted into the containing body 30, in substantially the same way as was described with reference to figs. 1-3.

According to the embodiment in fig. 7, a portion 85 of the piston 36 is inserted and in contact with the expandable substance 34, to receive thrust energy from this too.

In fact, the piston 36 not only thrusts the water of the compartment 12 because of the expansion of the expandable substance 34, but also thrusts it due to the action of the elastic device 32 when the valve 22 is opened.

Between the containing body 30 and the piston 36 an elastic element can be interposed, substantially analogous to the elastic element 38 described above, and provided to keep the piston 36 normally in its inactive position, that is, such as to generate the maximum volume of the compartment 12.

The elastic element 38 can be attached to the containing body 30 in correspondence with its bottom, and to the piston 36 in correspondence with its portion 85.

It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of coffee pot 10 and corresponding method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.