HK1129194B - Method and apparatus for producing beverages - Google Patents

Description

Method and apparatus for producing a beverage

Technical Field

The present invention relates to a method and an apparatus for producing a coffee beverage, in particular by steam pressure. Various types of espresso coffee machines, mainly for civil use, are known, in which the steam generated inside a brewing kettle exerts a pressure that pushes the water contained inside the brewing kettle through a coffee powder plate, thus producing a coffee beverage.

Background

These steam pressure coffee machines are hereinafter referred to as "mocha" coffee machines.

Figure E schematically shows a "mocha" coffee machine (indicated by the letter K) comprising a first and a second container that can be hermetically fastened together.

The first container, which is a brewing kettle, is shaped to contain a volume of water, which can be heated by a suitable heat source, and is provided with an overpressure valve, i.e. a safety valve, which is suitably adjusted and arranged to prevent the pressure inside the brewing kettle from exceeding a set limit value in case of a malfunction. In the second container, which is a reservoir, the produced coffee beverage is collected.

The "mocha" coffee machine also comprises a filtering funnel interposed between the brewing kettle and the tank to receive a set quantity of coffee powder, and a duct housed inside the tank and arranged to deliver the produced coffee beverage to the tank.

When it is desired to prepare coffee, a desired volume of water is poured into the brew kettle, a desired quantity of coffee is poured into the filter funnel, and the brew kettle is heated to boil the water.

As known to those skilled in the art, heating increases the pressure within the brewing kettle, which pushes the water within the brewing kettle through the filter funnel and thus through the coffee grounds. The latter is soaked with water, producing a coffee beverage which passes through a second filter located at the bottom of the tank, rises along the conduit and is discharged from the upper part of the conduit, collecting in the tank.

To heat the water in the storage tank, various heat sources such as a flame of a general gas burner, or an electric resistance may be used.

Figure F schematically shows another steam pressure coffee machine (indicated by the letter Z) which lacks a reservoir and in which the duct is shaped so as to deliver the produced beverage directly into a suitable container, such as one or more cups of the user, located at the outlet portion of the duct. The duct may be provided with an upper cover shaped so as to define a suitable outlet hole for the outflow of the beverage on the side of said duct. The upper cover is arranged to prevent the beverage pushed by the high pressure from splashing outside the tank.

Fig. G schematically shows another steam pressure coffee machine (indicated by the letter Y) provided with an autoclave-type brewing kettle containing water inside, which is heated by electricity. Steam is generated by heating, which pushes water through a coffee plate located on a filter holder from which the produced beverage flows. The produced beverage is collected in a suitable container, for example one or more cups of the user, located on the filter holder. The filter holder is shaped in a similar way as the filter holder used in espresso coffee machines in order to simulate the preparation of espresso coffee. The coffee machine disclosed above must dispense the coffee beverage in a relatively short time in order to correctly simulate the preparation of espresso coffee, and therefore the temperature inside the brewing kettle must reach a temperature value well above 1000 ℃ in a particularly short time.

A drawback of the above disclosed "mocha" steam pressure coffee machine is that the beverage produced by the latter is inferior in organoleptic properties to the beverage produced by infusion or by an "espresso" coffee machine, in which the extraction is not done by steam pressure, but by a pump that pushes hot water into contact with the coffee powder. This results from the specific temperature and pressure conditions that are generated inside these coffee machines during the extraction process.

In addition, the extraction by infusion or by pressure percolation, which can be obtained with "espresso" coffee machines, is clearly different from that which can be obtained in known steam pressure coffee machines, since the latter half of the coffee beverage is obtained by passing water mixed with water vapour through the coffee powder at high temperature (> 1000 ℃), as shown in figures 13-19.

In figure 13 is shown a mocha-type coffee machine K, which is initially a closed system from a thermodynamic point of view, containing water of capacity a and coffee powder in quantity W. Such a closed system tends to transform into an open system when it is placed on a heat source, as shown in fig. 18 and 19, by the expansion of the air inside the kettle, and in particular by the increase of the steam pressure of the water inside the kettle. By transitioning from the closed thermodynamic system phase in fig. 13 to an intermediate phase between the closed system and the open system (fig. 17), the temperature of the water or the corresponding pressure within the kettle gradually increases. For example, in a container containing 15g of coffee powder (ICN mix) and 150g Triest tap water in a 3-cup Mocha ExpressIn a coffee maker, a water temperature of approximately 111-114 ℃ corresponds to a brewing kettle pressure of 0.5bar (relative). If the heating is continued until the relative pressure in the kettle reaches 0.7bar, the water in the kettle reaches a temperature of about 115 and 117 ℃. In both cases, the gradually dispensed beverage has<A temperature of 100 ℃. When the beverage temperature reaches 100 ℃, the intermediate stage shown in fig. 17 transitions to the open thermodynamic system stage shown in fig. 18. Water undergoes a phase change at an elevated temperature>118 deg.c) and the steam in the brewing kettle begins to escape with the very hot water, passing through the coffee board, producing a typical noise corresponding thereto, also known as a rumble or glug, which represents the final preparation stage. When the coffee machine is in the open thermodynamic system phase shown in fig. 18 and 19, the coffee beverage C is extracted by the mixed water/steam system. The extremely hot water and steam that make up the mixing system act synergistically to extract the coffee beverage C, as well as the undesired substances, from the coffee powder W, since they greatly modify the organoleptic properties of the beverage produced.

By stably retaining the quantity of water (150g) and its initial temperature, the above-mentioned temperature and pressure values are hardly affected by the dose of coffee, while they can vary very uniformly according to the granulometry (and granulometric distribution) of the coffee powder, as is well known to those skilled in the art. It is also known that the amount of water and its initial temperature can influence the thermodynamics of the process and the heating rate.

However, experiments have shown that the dose of coffee during use significantly affects the maximum temperature obtainable in the brewing chamber of a coffee maker. Figure 20 shows a diagram of the temperature inside a brewing kettle of a known type of coffee machine as a function of the dose of coffee used. The diagram shows that the maximum temperature reached in the brewing kettle is below 130 ℃ in the case of about 9g of coffee and above 140 ℃ in the case of about 17g of coffee. The data shown in the diagram utilize a coffee powder (ICN mix) and 150g Triest tap water (3 cup Mocha Express)Coffee machine) was obtained by two measurements.

In order to solve the above problem, EP0607765 provides a coffee machine comprising two distinct brewing pots into which water is poured: a first brewing chamber placed in contact with the heat source, and a second brewing chamber placed between the first brewing chamber and the filter containing the coffee powder. When the water in the first kettle reaches its boiling point, the water exerts a pushing force on a piston disposed between the first kettle and the second kettle. The piston pushes the water (at a high temperature but below boiling) of the second boiler towards the coffee powder. Thus, a coffee beverage is obtained by soaking coffee powder in water at a temperature of 75-95 ℃.

EP0148982 likewise provides two distinct water brewing pots, one containing water to be brought to boiling point and the other containing water for brewing coffee powder. The presence of the second water brewing pot makes the coffee machines disclosed in EP0607765 and EP0148982 more complex in construction, above all with them having overall dimensions much greater than those of the known coffee machines.

In addition, dual pot coffee machines consume more energy than known coffee machines because a large amount of water must be heated and they take longer to prepare a coffee beverage.

In addition, IT is known from WO94/07400 or IT1245706 to cool water and/or steam which is forced to rise from a kettle by pressure which is generated inside the kettle by heating the water. The path of the water and/or steam to the coffee powder is modified in such a way that, before flowing through the coffee powder, the water and/or steam flows through the exchanger elements that cool the water and any steam that may be present condenses.

A drawback of the solution disclosed above is that the presence of the exchanger element makes these coffee machines more complex and makes them of greater overall dimensions than ordinary coffee machines.

Another drawback is that the maintenance and cleaning of the coffee machine must be particularly thorough, and therefore take longer than in the known coffee machines.

A further drawback is that these coffee makers consume more energy than the known coffee makers, because all the water in the brewing kettle is first heated and then cooled before coming into contact with the coffee powder.

Disclosure of Invention

The object of the present invention is to improve the known apparatus and method for producing a coffee beverage.

Another object is to provide a relatively simple device which enables the production of a coffee beverage having good organoleptic properties without excessive consumption of energy.

A further object is to provide a relatively simple apparatus which is capable of producing a coffee beverage using water which is not in a steam state.

It is a further object to provide a method for producing a coffee beverage using water which is not in a steam state.

In a first aspect of the present invention, an apparatus for preparing a coffee beverage is provided, comprising containing means for heating an extraction fluid, delivery means arranged to cause said fluid to flow through a dose of coffee and to send said coffee beverage to collection means, characterized in that it comprises restraining means arranged to restrain said flow when said fluid contains a substantially vapour phase, said restraining means being associated with said delivery means.

In a second aspect of the invention, an apparatus for preparing a coffee beverage is provided, comprising containing means for heating an extraction fluid, delivery means arranged to cause said fluid to flow through a dose of coffee and to send said extracted coffee beverage to collection means, characterized in that it comprises restraining means arranged to restrain said flow when said fluid contains a substantially vapour phase, said restraining means being associated with venting means opening into said collection means.

In a third aspect of the present invention, an apparatus for preparing a coffee beverage is provided, said apparatus comprising containing means for heating an extraction fluid, delivery means arranged to cause said fluid to flow through a dose of coffee, characterized in that it comprises suppression means arranged to suppress said flow when said fluid contains a substantially vapour phase, said suppression means comprising pressure regulation means arranged to regulate the pressure of said fluid inside said containing means and being different from overpressure regulation means contained inside said apparatus.

In a fourth aspect of the invention, a method of obtaining a coffee beverage is provided, said method comprising heating an extraction fluid to extract said beverage so as to direct said fluid through a dose of coffee, characterized in that said flow is inhibited when said fluid contains a substantially vapour phase, and in that the pressure of said extraction fluid is suitably regulated before said flow, said regulation being obtained by means of a pressure regulating device different from an overpressure regulating device.

Thanks to these aspects, a device is provided which is relatively simple and has a low energy consumption, and a method is provided which enables the production of a coffee beverage without the need to mix water at too high a temperature with water in the steam state. The coffee beverage thus obtained has good organoleptic properties, which are comparable to those of beverages obtained by "espresso" coffee machines.

It has in fact been found that by letting the steam exit in a controlled manner from the coffee machine of the "mocha" type, the latter are inhibited as a subsequent phase of the open thermodynamic system (fig. 18 and 19) until they are substantially eliminated, when the latter is in the operating phase disclosed above with reference to fig. 13-16, i.e. the phase preceding the transition from the closed thermodynamic system to the open thermodynamic system (fig. 17).

This technical effect, obtained by the restraining means and which is not appreciated, can greatly improve the organoleptic properties of the extracted coffee beverage C.

The suppression means comprise pressure regulation means able to maintain the relative pressure value of the extraction fluid inside the containing means in the range of about 0.01 to 6 bar.

In an embodiment, the pressure regulating means are capable of maintaining the relative pressure value of the extraction fluid in the range of about 0.2 to 1.0 bar.

In another embodiment, the pressure regulating means are capable of maintaining the relative pressure value of the extraction fluid in the range of about 0.3 to 0.8 bar.

When the apparatus for preparing a coffee beverage is ready, it is possible to preset pressure regulating means, which open to reduce the pressure of the extraction fluid when at said upper pressure limit and close again when at said lower pressure limit to bring the extraction fluid to the pressure value, so as to ensure the extraction of the beverage by the fluid in the substantially liquid phase. The upper and lower pressure limits depend on the geometrical characteristics and on the dimensions of the device on which the regulating device is arranged. The above-mentioned limit values can therefore be defined when designing and/or assembling the device. The pressure regulating means can be operated a desired number of times within the same beverage preparation cycle, i.e. each time the extraction fluid pressure is greater than the set limit value, in order to restore the pressure to the desired value.

In particular, the pressure regulating means can be put into operation whenever the pressure of the extraction fluid has to be controlled to ensure that the coffee beverage can only be obtained by infusion with water mainly in the liquid state. In this way, it is possible to obtain a beverage by only soaking a determined quantity of coffee with water (i.e. avoiding the coffee to be wetted by the fluid containing steam).

A prior art gravity operated valve (or a weight valve) of the type operating a valve in a pressure cooker may be used as the pressure regulating means, or a prior art spring valve with radial, lateral or other steam outlets known to those skilled in the art may be used.

In addition to the above-mentioned calibrated limit values, the steam flow also plays an important role and must be properly defined.

The calibration value, as known to those skilled in the art of spring valves, is typically referred to as a steam flow of 100 NL/h.

Spring valves having various pressure/flow curves may be used, such as shown in table 1 below:

TABLE 1

Pressure of	Flow (NL/h)	Flow (NL/h)	Flow (NL/h)	Flow (NL/h)
					(bar)	Spring valve 1	Spring valve 2	Spring valve 3	Spring valve 4
0	0	0	0	0
					0.05	0	0	0	0
0.1	0	0	0	0
					0.15	0	0	0	0
0.2	0	0	0	0
					0.25	0	0	0	0
0.3	0	0	0	0
					0.35	0	25	0	0
0.4	25	30	25	0
					0.45	30	40	80	0
0.5	50	60	100	0
					0.55	80	70	Over 250	25
0.6	100	100		50
					0.65	140	120		100
0.7	170	140		200
					0.75	Over 250	170		Over 250
0.8		250
					0.85		Over 250

It should also be noted that the device construction is rather simple and the energy consumption is low, since no heat exchanger elements, auxiliary kettles or pistons are required.

The coffee may be in powder form or comminuted for convenient extraction, or in the form of capsules, portions or cartridges containing a predetermined dose of coffee powder. In either case, the coffee plate generates a variable load as a function of time and/or temperature, the initial conditions of which are defined by the composition of the coffee powder and the granulometry of the latter. In fact, the degree of pulverization of the coffee powder and its granulometry are correlated to the resistance of the coffee plate to the flow of the extraction liquid. Thus, the pressure regulating means (i.e. the valve) is calibrated in a variable and suitable manner during manufacture, according to the particle size of the coffee powder used.

As known to the person skilled in the art, in coffee powder the granulometry values (expressed in μm) are statistically distributed according to a multimodal distribution curve, which can vary on the basis of the degree of pulverization of the powder. Table 2 below shows the ranges of the statistical parameters, each obtained by statistically comparing the various distributions of the particle sizes of the coffee powders suitable for use in the coffee machine with the pressure regulating device described above. The particle size is determined experimentally by known methods and devices.

TABLE 2

Statistical parameters	Particle size range (μm)
		Mean average (Mean average)	500-200
Average middle point (Median average)	500-100
		Mode average (Modal average)	700-500
Less than 10%	20-10
		Less than 25 percent	60-30
Less than 50%	500-100
		Less than 75%	750-450
Less than 90 percent	950-650

Table 2 shows, for example, that coffee powder is particularly suitable for use in one of the devices provided by the present invention when its average particle size is about 500 to 200 μm.

Drawings

The invention may be better understood and put into practice by referring to the accompanying drawings which show, by way of non-limiting example, embodiments of the invention in which:

figure 1 is a schematic longitudinal section of a coffee machine of the "mocha" type provided with pressure regulating means;

FIG. 2 is a schematic longitudinal cross-sectional view of the embodiment of the coffee maker of FIG. 1;

FIG. 3 is a schematic longitudinal cross-sectional view of another embodiment of the coffee maker of FIG. 1;

FIG. 4 is a schematic longitudinal cross-sectional view of yet another embodiment of the coffee maker of FIG. 1;

FIG. 5 is a schematic longitudinal cross-sectional view of yet another embodiment of the coffee maker of FIG. 1;

FIG. 6 is a three-cup MochaA schematic side view of a coffee machine of the type shown in the manner of operation of the electronic control system of the pressure regulating device;

figure 7 is a schematic longitudinal section of a further "mocha" type coffee machine provided with pressure regulating means;

FIG. 8 is an enlarged, fragmentary, schematic longitudinal cross-sectional view of a detail of the coffee maker of FIG. 7;

FIG. 9 is a schematic longitudinal cross-sectional view of the embodiment of the coffee maker of FIG. 7;

FIG. 10 is a schematic longitudinal cross-sectional view of another embodiment of the coffee maker of FIG. 7;

FIG. 11 is a schematic longitudinal cross-sectional view of yet another embodiment of the coffee maker of FIG. 7;

FIG. 12 is a schematic longitudinal cross-sectional view of yet another embodiment of the coffee maker of FIG. 7;

figures 13-19 schematically show a longitudinal section of a coffee machine of the "mocha" type of the prior art, and illustrate its operation;

figure 20 is a graph showing how the dose of coffee affects the maximum temperature that can be reached in the brewing kettle of a coffee machine of known type;

fig. E, F and G schematically show longitudinal sections of various prior art steam pressure coffee machines.

Detailed Description

With reference to fig. 1, a coffee machine 1 comprises a brewing kettle 2 into which water to be heated is poured and which is placed in contact with a heat source, and an upper portion of a tank portion 3, which in use is fastened to the brewing kettle 2.

The coffee machine 1 further comprises a hopper-like container 5 comprising a chamber or containing portion 6 delimited therebelow by a filter surface or plane 6a and a tube or duct portion 7 projecting from said containing portion 6, into which a desired quantity of powder, i.e. a dose of coffee W, is poured. The funnel container 5 is inserted into the brewing kettle 2 in such a way that the conduit portion 7 extends from the receiving portion 6 to the bottom of the brewing kettle 2.

The reservoir portion 3 comprises a lower or filtering bottom 8, a reservoir 9 inside which the produced coffee beverage collects and which is connected to the filtering bottom 8 by a hollow or delivery duct 10, a handle 11 which can be gripped by the user, a side or lateral wall 12 provided with a projection or lip 13 for the beverage to flow through, and a movable and removable lid 14 hinged to the lateral wall 12 at a hinge 114 a.

The delivery conduit 10 is mounted to the bottom 90 of the tank 9 and comprises a base 20, which is substantially conical and arranged on the bottom 90, and a delivery portion 21, which is connected to the base 20 by a connecting area 22.

The base 20 conveys the coffee beverage C on the filtering bottom 8 to a delivery portion 21, which extends from the connecting region 22 to an upper region or end 10z of the delivery duct 10, into which the coffee beverage flows and then drains into the upper region 10 a. The conveying portion 21 may be cylindrical or slightly tapered upward.

The end portion 10a of the delivery conduit 10, from which the obtained coffee beverage flows out, may have a completely open outlet portion or be provided with a partially open portion 10 b. In the latter case, the coffee beverage C produced flows out from a suitable opening 10C provided on the delivery duct 10.

The delivery duct 10 has a total longitudinal extent, defined as the distance between the bottom filtering surface 8 and the partial covering portion 10b, which depends on the volume of beverage (number of cups) desired to be obtained.

The coffee maker 1 further comprises a safety valve (not shown) arranged to prevent the pressure inside the brewing chamber 2 from exceeding a set maximum value and adapted to open in case of malfunction of the coffee maker 1. This makes it possible to avoid dangerous situations for the user of the coffee maker 1.

The coffee maker 1 further comprises a regulating valve 4 arranged to prevent the pressure inside the brewing chamber 2 from exceeding a set maximum value, said regulating valve 4 being preset in such a way as to maintain the pressure value inside the brewing chamber 2 in the range of 0.01 to 5 bar. These pressure values are relative pressure values, i.e. they assume an atmospheric pressure value of 0 bar.

The regulating valve 4 is preset in such a way as to open at an upper pressure limit, reducing the pressure of the extracted fluid inside the brewing chamber 2 to a lower pressure limit at which the regulating valve 4 closes again.

In this way, the regulating valve 4 acts in such a way that a positive pressure is maintained in the brewing chamber 2, to the extent that water is allowed to flow through the coffee powder W, but steam is prevented from flowing through the coffee powder.

By keeping the pressure inside the brewing chamber 2 below the upper limit value set for the regulating valve 4, it is possible to prevent excessive steam generation inside the brewing chamber 2, thus preventing the coffee beverage from being obtained with water in a steam state.

In fact, the formation of a large amount of steam increases the pressure inside the brewing kettle 2, thus causing the regulating valve 4 to open, the steam being discharged outside the brewing kettle 2 and the inside of the brewing kettle 2 to return to the desired pressure state.

As shown in fig. 1, the regulating valve 4 may be positioned on the side 2a of the brewing kettle 2.

Referring to fig. 2, showing a coffee maker 1 similar to that shown in fig. 1, the reservoir portion 3 is provided with an exhaust tube 140.

The exhaust duct 140 projects on the portion 41 of the side wall 12 and is formed in such a way that, in use, the lower portion 42 of the exhaust duct surrounds the regulating valve 4 to receive the steam discharged from the regulating valve 4. The steam is then exhausted from under the lip 13 through the upper portion 43 of the exhaust pipe 140.

In fig. 3, which shows a coffee maker 1 similar to that shown in fig. 1, corresponding parts are indicated with the same reference numerals.

In the embodiment of fig. 3, the regulating valve 4 is located on a region 91 of the bottom 90 of the tank 9 and connection means 92 are provided to connect the regulating valve 4 to the brewing kettle 2. A further exhaust pipe 93 is also provided, which is arranged to receive the steam discharged by the regulating valve 4, said exhaust pipe 93 extending inside the tank 9 almost parallel to the conduit 10 and being positioned in such a way that a lower part 94 of the further exhaust pipe 93 surrounds the regulating valve 4 and an upper part 95 of the further exhaust pipe 93 is arranged below the cover 14.

The embodiment of the coffee maker 1 shown in fig. 4 is very similar to the embodiment shown in fig. 3, however, it differs from the latter in that the regulating valve 4 is located in the upper part 95 of the further exhaust duct 93.

In the embodiment disclosed in fig. 3 and 4, the steam discharged by the regulating valve 4 is released inside the storage tank 9.

In the embodiment shown in fig. 5, the regulating valve 4 is located on another region 96 of the bottom 90 of the reservoir 9, so that the steam discharged by the regulating valve 4 is released into the reservoir 9 directly into the coffee beverage C inside the reservoir 9. In this embodiment, there is also provided a distribution means 100 located between the regulating valve 4 and the coffee beverage C, arranged to distribute the steam emitted by the regulating valve 4 within the coffee beverage C. This will create foam within the coffee beverage C.

In an embodiment not shown, the dispensing device 100 can replace a regulating valve, in fact by suitably calibrating and/or configuring it, it is possible to regulate the pressure inside the boiler 2 of the coffee machine 1. The excess steam generated inside the brewing chamber 2 is released through the dispensing device 100 into the beverage which is only obtained when pushed by a force sufficient to overcome the resistance of the dispensing device, i.e. the pressure inside the brewing chamber 2 exceeds the desired value.

With the coffee machine 1 shown in fig. 5, it is possible to obtain a coffee beverage that is completely similar to the coffee beverage produced by an espresso machine, including not only organoleptic properties but also appearance.

The foam of the coffee beverage has a persistence and characteristics that vary according to the dispensing device 100 used, as well as a particular configuration that depends, for example, on the size of the dispensing holes provided on the dispensing device 100.

As the dispersing means, suitable known dispersing means such as porous material, porous baffle, slit baffle, elastic membrane, sintered glass can be used. In addition, an appropriately sized orifice or nozzle is provided at the outlet portion of the regulating valve 4.

In FIG. 6, Mocha Express is shownThree-cup coffee machine "M" of the type provided with an electronic control system 200 for controlling an electronically regulated valve 4' arranged to prevent the generation of pressure conditions inside the brewing kettle 2 for extracting the coffee beverage with water in the steam state.

The electronic control system 200 comprises a pressure sensor 201 arranged in communication with the brewing chamber 2 for automatically detecting the pressure inside the brewing chamber 2 and automatically transmitting a signal to an amplifier 202 which amplifies said signal to adapt it to the sensitivity level of the microprocessor 203.

The microprocessor 203 receives the signal from the amplifier, compares it with a comparison upper limit value and a comparison lower limit value predetermined and preset in the microprocessor 203, and if the value recorded is greater than the comparison upper limit value, commands the control device, for example a triac 204, to open the electroregulating valve 4'.

In this way, the electroregulating valve 4' opens, releasing a given quantity of steam from the brewing chamber 2, so as to restore the pressure value inside the brewing chamber 2 to the desired pressure value range.

When the pressure value detected by the sensor 201 and received by the microprocessor 203 is lower than the lower comparison limit, the microprocessor 203 commands, through the triac 204, the closing of the electroregulating valve 4'.

Also in this case, the electroregulating valve 4' is opened and closed several times during the same coffee beverage preparation cycle.

The conditioning system 200 may be operated in a continuous manner during operation of the coffee maker 1.

In an embodiment not shown, the control system 200 can be provided in a suitable portion of the body of the coffee machine 1, in the base of the electric coffee machine or in some sort of sleeve outside the brewing kettle, or in other desired portions to obtain a coffee machine with more variations and a desired design.

For preparing a coffee beverage, a suitable amount of water is poured into the brewing kettle 2, a suitable amount of coffee powder is poured into the funnel-shaped receptacle 5, which is inserted into the brewing kettle 2, the upper part 3 is fastened to the brewing kettle 2, and the coffee maker 1 is subsequently heated by the heat source.

The water in the brewing chamber 2 heats up, causing an increase in pressure, which pushes a portion of the water in the brewing chamber 2 upwards through the conduit 7 until it comes into contact with the coffee powder, causing the latter to become wet and thereby extracting the coffee beverage C. The coffee beverage C passes through the filtering bottom 8, rises through the duct 10 to the upper region 10a to flow out of the latter through the holes 10C and collects in the tank 9.

By heating and the resulting increase in pressure and temperature in the brewing chamber 2, after a certain time the extraction of the coffee beverage tends to take place by solid-liquid-vapour extraction. A properly calibrated regulating valve 4 allows to avoid solid-liquid-vapor extraction, since when the pressure inside the brewing chamber 2 reaches the value at which extraction takes place, the regulating valve opens, expelling air and vapor and reducing again the pressure inside the brewing chamber 2.

Mocha Express with appropriate modifications, for example, similar to that shown in FIG. 6Three-cup coffee machine of coffee machine, comprising 15g of coffee powder: (Mixture) and 150ml of water having a hardness of about 18-20 ° f to produce a coffee beverage, it has been shown that in order to obtain a coffee beverage by only steeping the coffee powder with water in liquid state, the regulating valve must be opened to vent steam when the pressure in the brewing chamber reaches 0.7bar and closed when the pressure in the brewing chamber reaches 0.5 bar. This enables to obtain a beverage with good organoleptic properties with the coffee machine disclosed above.

If air and steam are discharged into the beverage through a suitable distribution means capable of generating a plurality of bubbles, micro-bubbles, it is possible to have a froth layer floating on top, giving the beverage a very similar appearance to espresso coffee preparation. The smaller the diameter of the generated bubbles, the longer the persistence of foam formation in the beverage. This also enhances the appearance of the produced coffee beverage, providing the user with a full perception of drinking the beverage, similar to that obtained with espresso coffee preparation.

In addition, by suitably varying the form of the structural elements and the position and structure of the pressure regulating valve within the coffee machine 1, it is possible to obtain a device (disclosed hereinafter with reference to figures 7-12) having a shape adapted to the various design requirements and capable of producing a coffee beverage with good organoleptic properties.

Figures 7 and 8 show a coffee machine 1 comprising a brewing kettle 2, into which a suitable volume a of water to be heated is poured in use and which is in contact with a heat source (not shown), and a tank portion 3 fastened to the brewing kettle 2. Between the brewing kettle 2 and the tank portion 3, known sealing means are provided, such as a ring seal 40. The brewing kettle 2 is provided with a safety valve (not shown) of known type arranged to prevent the pressure inside the brewing kettle 2 from exceeding a predetermined maximum value in use. If an undesired overpressure is generated due to a malfunction of the coffee maker 1, the safety valve opens and vents the overpressure to the outside, thereby preventing a situation that is dangerous for a user of the coffee maker 1.

The funnel container 5 is inserted into the brewing kettle 2 in use, the funnel container 5 comprising a receiving portion 6 and a conduit portion 7, between which a substantially circular filter surface 6a is arranged. The containing portion 6 is substantially shaped as a hollow cylinder and is adapted to receive a desired quantity (dose) of coffee powder W. The duct portion 7 is substantially conical near the filter surface 6a and then narrows abruptly so as to be substantially cylindrical. Funnel container 5 is inserted vertically into brewing kettle 2 such that receiving portion 6 faces in a direction opposite to bottom 2a of brewing kettle 2, and conduit portion 7 faces bottom 2 a.

The reservoir portion 3 comprises a reservoir 9 delimited by a side wall 12, in which the coffee beverage C is collected at the time of production.

The bottom 90 of the reservoir 9 is closed by a filtering bottom 8 which is slightly concave towards the containing portion 6 of the funnel 5. A handle 11, which can be gripped by a user, is secured to a portion of the side wall 12 opposite the bottom 90. The side wall 12 delimits, in a position opposite the handle 11, a lip 13 through which the user can pour the coffee beverage C. The upper side of the tank 9 is closed by a lid 14 which is hinged to the side wall 12 by hinge means (not shown) and can be lifted to inspect the tank 9. A substantially cylindrical covering member 15 is fixed at a substantially central portion of the visible surface 14a of the cover 14. On the covering element 15 there is a recess 15a, which is substantially cylindrical and communicates with the outside environment through an exhaust opening (not shown) in the covering element 15. The recess 15a is intended to receive a gravity operated regulating valve 16 of a known type, the structure and function of which will be described in more detail below. When the cover element 15 is secured to the lid 14 at a position close to the opening 46 of the lid 14, the recess 15a communicates with the underlying reservoir 9. From a substantially central region of the bottom 9, a delivery duct 10 projects in the direction of the lid 14, the dimensions of which are set on the basis of the volume of coffee beverage C (i.e. the number of cups) that is desired to be obtained by the coffee maker 1. The delivery catheter 10 comprises a substantially dome-shaped base 20 from whose substantially central region a substantially conical delivery portion 21 projects in the direction of the cover 14.

In use, the base 20 receives, through the filtering bottom surface 8, a coffee beverage C obtained by extraction inside the containing portion 6 of the funnel 5. The coffee beverage C rises from the base 20 to the delivery portion 21 and flows upwards along the latter until it reaches the end portion 10a corresponding to the tip of the delivery duct 10. At the end portion 10a there is an outlet conduit 18, which is cylindrical and arranged perpendicularly with respect to the conveying conduit 10. Through the communication hole 210b, the coffee beverage C coming from the delivery portion 21 enters the outlet conduit 18 and exits the latter through the two opposite end holes 18a, 18b, then discharging into the tank 9.

A housing 31 is mounted on the outside of the delivery catheter 10, said housing being form-connected to the delivery catheter 10 and defining with the latter an air passage gap 30 circumferentially surrounding the delivery catheter 10. The venting gap 30 communicates with the brewing chamber 2 via a plurality of duct or slot shaped channel elements 32. Each channel element 32 comprises a first channel portion 32a and a second channel portion 32b, which are aligned with each other and are obtained in an area corresponding to the tank portion 3 and to the brewing jug 2 (fig. 2). Near the end portion 10a of the delivery duct 10, the vent gap 30 extends beyond the outlet duct 18 and substantially surrounds the latter and opens into a chamber 33. The vent conduit 34 opens into the chamber 33, said vent conduit being taken along the longitudinal axis (not shown) of the cylindrical body 16a of the gravity-operated regulating valve 16. The airway tube 34 passes through the entire body 16a and opens adjacent the valve member 16 b. A shutter element 16b, which is in form connection with the body 16a and the recess 15a, is arranged to selectively open or close the vent conduit 34 of the body 16 a. A discharge hole 16c is provided near the free edge of the shutter member 16 b.

When the valve element 16b is spaced from the body 16a (i.e. when the gravity operated regulating valve 16 is open), the discharge channel 34 is open, which places the brewing chamber 2 in communication with the environment through the channel element 32, the venting gap 30, the chamber 33, the venting conduit 34, a further gap (not shown) formed between the body 16a and the valve element 16b when the valve element 16b is spaced from the body 16a, the discharge aperture 16c of the valve element 16b and the discharge aperture of the cover element 15. Vice versa, when the shutter element 16b rests against the body 16a in such a way as to close the discharge channel 34, the gravity-operated regulating valve 16 is closed and the brewing chamber 2 is isolated from the outside environment.

The gravity-operated regulating valve 16 is calibrated in such a way as to maintain the relative pressure value generated inside the brewing chamber 2 (i.e. the pressure defined by assuming an atmospheric pressure value equal to 0 bar) at 0.01 to 6bar, preferably (as shown in experimental tests) in the range 0.2 to 1.0bar, more preferably 0.3 to 0.8 bar. This means that the gravity operated regulating valve 16 is opened when the pressure inside the kettle 2 reaches and exceeds a predetermined upper limit value and is closed when said pressure reaches and falls below a lower limit value.

Since the beverage is obtained by extraction with hot water mixed with steam, the value of the pressure at which the valve must be opened depends on the quantity of beverage desired to be obtained or on the quantity of beverage desired to be discarded. For example, using a three-cup Mocha ExpressCoffee machine, 15g of ground coffee: (Mixture) and 150g Triest tap water, 130-140ml of beverage was obtained on average. In order to improve the organoleptic properties of the extracted beverage, the last fraction, about 20-40ml, obtained by extraction with high-temperature water mixed with steam, must be discarded, i.e. production of this last fraction is prevented. This is obtained by opening a valve which must then be calibrated to prevent the production of the last part of the beverage described above.

To prepare a coffee beverage with the coffee maker 1 shown in fig. 7 and 8, a volume a of water is poured into the brewing kettle 2 and a quantity W of coffee powder is poured into the funnel 5, which is inserted vertically into the brewing kettle 2. The reservoir portion 3 is fastened to the brewing kettle 2 and the coffee maker 1 is heated by the heat source. The water contained in the boiler 2 is heated and causes an increase in pressure which pushes a portion of the water up through the duct portion 7 and through the filter surface 6a, thus coming into contact with the coffee powder W. The water wets the coffee powder W, thereby extracting the coffee beverage C which flows through the filtering bottom 8 and, as disclosed previously, rises completely along the conveying duct 10 and flows out through the ducts 18a, 18b, finally collecting in the tank 9.

By the effect of the temperature and pressure increase occurring within the brewing chamber 2, the coffee beverage C tends to be extracted in the solid-liquid-vapour phase, as steam and hot water tend to flow through the quantity W of coffee powder.

This is avoided in the coffee maker 1 due to the gravity operated regulating valve 16. In fact, when the pressure inside the brewing chamber 2 reaches and exceeds the upper limit value, the shutter element 16b rises and is isolated from the body 16a and the venting duct 34 opens, opening the gravity-operated regulating valve 16, thus putting the brewing chamber 2 in communication with the outside environment. This enables air and steam to escape outside the brewing chamber 2, reducing the pressure in the latter below an upper limit value. If the pressure decreases to or below the predetermined lower limit, the valve member 16b bears against the body 16a to close the vent conduit 34, thereby closing the gravity operated regulator valve 16.

In this way, the gravity-operated regulating valve 16 ensures that a positive pressure is maintained inside the brewing chamber 2, allowing the water inside the brewing chamber 2 to flow through the quantity W of coffee powder, while preventing steam from flowing through the quantity W of coffee powder. By keeping the pressure in the brewing chamber 2 below the upper limit value by means of the gravity-operated regulating valve 16, it is possible to prevent excessive steam from forming in the brewing chamber 2 and thus to prevent the coffee beverage C from being produced from water in a steam state. In fact, when a greater amount of steam is formed, this causes a pressure increase in the brewing chamber 2, thus causing the gravity-operated regulating valve 16 to open and steam to flow out of the brewing chamber 2, thereby restoring the desired pressure conditions in the brewing chamber 2.

Fig. 9 shows an embodiment of the coffee maker 1 which differs from the coffee maker disclosed with reference to fig. 7 and 8 only in that the gravity-operated regulating valve 16 is replaced by a spring-operated regulating valve 17 and that a lever element 56 is fixed to the lid 14 close to the handle 11, by means of which lever element the lid 14 can be raised and the reservoir 9 can be checked. The regulating valve 17, of known type, comprises a cylindrical body 17a inside which a spring and a piston (not shown) are housed. The spring is arranged to press the piston against a discharge orifice (not shown) of the spring operated regulating valve 17 in order to close said orifice and the spring operated regulating valve 17. The spring is calibrated in such a way as to keep said piston pressed against the discharge hole until an upper pressure limit is reached inside the brewing chamber 2. When the upper pressure limit is reached and exceeded, the spring can no longer hold the piston in place, the piston is removed from the discharge orifice and the spring-operated regulating valve 17 is opened.

A spring-operated regulating valve 17 is mounted above the end portion 10a of the delivery conduit 10, between the chamber 33 obtained on the latter and the cover 14. The covering element 15 is replaced by an approximately oval knob 55, around which there are a plurality of outlet holes 35 on the cover 14.

When the pressure in the brewing chamber 2 reaches and exceeds the upper limit value, the spring-operated regulating valve 17 opens, putting the brewing chamber 2 in communication with the environment. Excess steam flows out of the tank 9 through the outlet opening 35 after flowing through the passage element 32, the venting gap 30, the chamber 33 and the discharge opening of the spring-operated regulating valve 17. When the pressure in the kettle 2 is below the lower limit value, the spring presses the piston back against the discharge hole and the spring-operated regulating valve 17 closes again.

Fig. 11 shows a further embodiment of the coffee maker 1, which is equipped with a spring-operated regulating valve 17 and is provided with an embodiment of a delivery duct, which is denoted by the numeral 110, and with an embodiment of a venting gap, which is denoted by the numeral 130.

The delivery conduit 110 comprises a base 120 having an irregular arch shape with a generally conical delivery portion 121 projecting from an edge region of the base in a direction towards the lid 14. At the end 110a of the delivery duct 110 corresponding to the tip of the latter, there is an outlet hole 19 through which the produced coffee beverage C is discharged into the tank 9.

The air gap 130 is located between the delivery catheter 110 and a housing 131 which is form-connected to the delivery catheter 110 and only partially surrounds the latter. In the embodiment shown in fig. 5, the housing 131 is made integrally with the delivery duct 110 and the side wall 12 of the tank 9. The gap 130 communicates with the brewing chamber 2 via a plurality of channel elements 132, said channel elements 132 being made in a substantially similar manner as the channel elements 32 disclosed with reference to fig. 1 and 2. Each channel element 132 comprises a first channel portion 132a and a second channel portion 132b, which are aligned with each other and are obtained in respective areas with the tank portion 3 and the brewing chamber 2.

A spring operated regulating valve 17 (the function and structure of which is disclosed with reference to fig. 3) is accommodated at the end of the vent gap 130 and faces the outlet opening 35. The spring-operated regulating valve 17 is generally placed alongside the outlet aperture 19 of the delivery conduit 110 and is arranged along the longitudinal axis (not shown) of the tank 9.

The lid 14 can be lifted by operating a lever 56a which is fixed to the lid 14 in the vicinity of the handle 11 and is hinged thereto.

When the pressure in the brewing chamber 2 reaches and exceeds a predetermined upper limit value, the spring-operated regulating valve 17 opens, placing the brewing chamber 2 in communication with the environment. Excess steam flows out of the tank 9 through the outlet opening 35 after flowing through the passage element 132, the vent gap 130 and the discharge opening of the spring-operated regulating valve 17. When the pressure in the kettle 2 is below the lower limit value, the spring presses the piston back against the discharge hole and the spring-operated regulating valve 17 closes again.

Fig. 12 shows a further embodiment of a coffee maker 1 which is equipped with a further spring-operated regulating valve 117 and comprises a venting conduit 60.

The venting duct 60 is obtained along the depth of the lateral wall 12 of the tank 9, at a position opposite the lip 13, and extends obliquely between the bottom 90 of the tank 9 and the lid 14. At the end of the airway tube 60 there is a passage hole 60a facing the lid 14, through which the airway tube 60 communicates with a further airway gap 61 obtained in the lid 14. More precisely, the end of the airway tube 60 that is open and facing the cap 14 and the adjacent open end of the further airway gap 61 together define a passage aperture 60 a. In an embodiment not shown, the passage hole 60a is made in a region of the coffee maker 1 different from the lid 14 (e.g. the side wall 12 of the reservoir portion 3).

Another spring operated regulator valve 117 is mounted at the end of the vent conduit 60 opposite the access port 60 a. Another spring operated regulator valve includes an elongated hollow cylindrical body 117a that is obliquely disposed within the airway tube 60 and has a transverse diameter that is less than the cross-section of the airway tube 60. Inside the body 117a, a spring 117d keeps the plunger 117b pressed against the discharge hole 117c, so as to close the latter and close the other spring-operated regulating valve 117. The spring 117d is calibrated in such a way as to keep the piston 117b pressed against the discharge hole 117c until an upper pressure limit is reached inside the brewing chamber 2.

The discharge hole 117c communicates with the underlying brewing kettle 2 through a channel element 154, said channel element 154 being made in a similar way as the channel element 32 disclosed with reference to fig. 1 and 2 and comprising a first channel portion 154a and a second channel portion 154b, which are aligned with each other and obtained on respective areas of the reservoir portion 3 and the brewing kettle 2. When the discharge hole 117c is opened, that is, when the other regulating valve 117 is opened, the brewing pot 2 and the ventilating duct 60 communicate with each other through the passage member 154.

A further ventilation gap 61 is located between the cover 14 and a plate 14b which is form-connected to the cover 14 and is fixed on the surface of the cover 14 opposite the viewing surface 14 a. The further venting gap 61 communicates with the external environment through the outlet hole 35 obtained on the cover 14 around the knob 55, and with the venting duct 60 through a passage hole 60a delimited by the further venting gap 61 and the respective end of the venting duct 60. There are also bleed holes 62 in the plate 14b through which various condensates can drain out of the further venting gap 61.

When the pressure in the brewing chamber 2 reaches and exceeds a predetermined upper limit value, the further spring-operated regulating valve 117 opens, placing the brewing chamber 2 in communication with the environment. Excess steam flows out of the further venting gap through the outlet opening 35 after flowing through the channel element 154, the further open spring-operated regulating valve 117, a portion of the venting conduit 60, the channel hole 60a and the further venting gap 61. When the pressure in the brewing chamber 2 is below the lower limit value, the spring 117d presses the piston 17b back against the discharge hole 117c and the further spring-operated regulating valve 117 closes again.

In an embodiment not shown, the at least one outlet opening 35 is made in an area of the coffee maker 1 different from the lid 14 (e.g. the side wall 12 of the reservoir portion 3).

Fig. 10 shows a further embodiment of a coffee maker 1 which is equipped with a spring-operated regulating valve 17 and comprises a further venting duct 50. The latter has a substantially inverted "L" shape and comprises a body portion 51 and a terminal portion 52. The delivery duct 10 opens inside the tank 9 through one or more outlet holes 19 obtained on the end portion 10 a.

The main body portion 51 of the further airway tube 50 is generally cylindrical in shape and projects from a peripheral region of the base 90, extending parallel to the delivery tube 10 and to the vicinity of the lid 14. At the bottom 90, the body part 51 communicates with the brewing chamber 2 via the channel element 54. The channel element 54, manufactured in a substantially similar way as the channel element 32 disclosed with reference to fig. 1 and 2, comprises a first channel portion 54a and a second channel portion 54b, which are aligned with each other and obtained on respective areas of the tank portion 3 and of the brewing jug 2.

A spring-operated regulating valve 17, the function and structure of which has been disclosed with reference to fig. 3, is mounted at the end of the body portion 51 facing in the opposite direction to the passage conduit 54.

The terminal portion 52 of the further venting duct 50 is cylindrical and projects obliquely from the body 17a of the spring-operated regulating valve 17 towards the central portion of the cover 14, so as to reach in proximity of the outlet hole 35. Terminal portion 52, having an outlet end 53, is elbow-shaped and is substantially aligned with end 10a of delivery conduit 10.

When the pressure in the brewing chamber 2 reaches and exceeds a predetermined upper limit value, the spring-operated regulating valve 17 opens. Through the channel element 54 and the body portion 51, excess steam from the brewing chamber 2 is discharged through the spring-operated regulating valve 17 in the terminal portion 52, so as to flow out of the reservoir 9 through the outlet opening 35.

The coffee maker 1 may be connected to any heat source suitable for heating the water of the brewing kettle 2, such as a gas range or an electric hot plate.

In an embodiment not shown, the heat source is integrated directly inside the coffee machine 1, for example by inserting an electric resistance in the body of the coffee machine, said electric resistance being powerable by a power supply device of known type.

In another embodiment, not shown, the present invention provides that the suppression means cooperate with signalling means arranged to send an alarm signal to the user of the coffee maker 1.

In a further embodiment, not shown, the invention provides that the suppression means comprise switching means for switching on and off the appliance comprising the coffee maker 1.

Claims (134)

1. An apparatus for preparing a coffee beverage (C), comprising: containing means (2) for heating an extracted fluid, conveying means (5, 10) arranged to cause said fluid to flow through a dose (W) of coffee and to send said extracted coffee beverage (C) to collecting means (9), characterized in that said apparatus comprises pressure regulating valve means (17; 117) arranged to inhibit said flow when said fluid contains a substantially vapour phase, said pressure regulating valve means (17; 117) comprising a spring-operated regulating valve (17; 117) and being associated with venting means (50, 54; 60, 61, 154) opening into an opening (35; 60a) of said collecting means (9).

2. The apparatus according to claim 1, wherein said opening (35; 60a) is obtained on cover means (14) of said collecting means (9).

3. The device according to claim 1 or 2, wherein the venting means (50, 54; 60, 61, 154) comprise a venting gap (61) to the outside environment, and the opening (60a) communicates with the venting gap (61).

4. An apparatus according to claim 1, wherein the airway device (50, 54; 60, 61, 154) comprises an airway tube device (60; 50).

5. Apparatus according to claim 4, wherein said airway tube means (60; 50) comprises an airway tube (60) obtained on wall means (12) of said collecting means (9).

6. The device according to claim 5 when dependent on claim 3, wherein the opening (60a) places the airway tube (60) and the airway gap (61) in communication with each other.

7. The apparatus according to claim 3, wherein said opening (35; 60a) is obtained on a cover device (14) of said collecting device (9) and said venting gap (61) is obtained on said cover device (14).

8. The device according to claim 7, wherein the vent gap (61) is located between a visible surface (14a) and a further surface (14b) of the cover (14), the visible surface (14a) and the further surface (14b) being opposite to each other.

9. Apparatus according to claim 8, wherein the escape means (62) is obtained on said other surface (14 b).

10. The apparatus of claim 8 or 9, wherein said opening (35; 60) comprises at least one outlet hole (35) obtained on said visible surface (14 a).

11. The device according to claim 10, wherein the venting means (50, 54; 60, 61, 154) comprises a venting gap (61) to the ambient environment, and the at least one outlet hole (35) communicates the venting gap (61) with the ambient environment.

12. The device according to claim 5, wherein said spring-operated regulating valve (17; 117) is housed within said ventilation duct (60).

13. The device according to claim 12, wherein said spring-operated regulating valve (17; 117) is arranged in the vicinity of the end of said venting duct (60) facing in the opposite direction to said opening (60 a).

14. An apparatus as claimed in claim 4, wherein the airway tube device (60; 50) comprises a further airway tube (50).

15. Apparatus according to claim 14, wherein said further airway tube (50) comprises a main body portion (51) projecting from a base portion (90) of said collection means (9).

16. Apparatus according to claim 15, wherein said opening (35; 60a) is obtained on cover means (14) of said collecting means (9) and said body portion (51) is close to said cover (14).

17. An apparatus as claimed in claim 15, wherein the further airway tube (50) comprises an end portion arranged obliquely to the body portion (51).

18. The apparatus of claim 17, wherein the opening (35; 60a) comprises at least one outlet hole (35), the end portion (52) being proximate to the at least one outlet hole (35).

19. The apparatus of claim 17, wherein the end portion (52) includes an elbow-shaped outlet portion (53).

20. Apparatus according to claim 19, wherein said outlet portion (53) is substantially aligned with a longitudinal axis of said collection device (9).

21. The device according to claim 14, wherein said spring-operated regulating valve (17; 117) is comprised in said further venting conduit (50).

22. An apparatus as claimed in claim 21, wherein said further venting duct (50) comprises a main portion (51) projecting from a bottom (90) of said collecting device (9) and an end portion (52) arranged obliquely with respect to said main portion (51), and wherein said pressure regulating valve device portion (17; 117) is located between said main portion (51) and said end portion (52).

23. An apparatus according to claim 4, wherein said venting means (50, 54; 60, 61, 154) comprises a channel element (54; 154), said channel element (54; 154) being located between said venting duct means (60; 50) and said containing means (2) in such a way that said venting duct means (60; 50) and said containing means (2) are in communication with each other.

24. The device according to claim 23, wherein the channel element (54; 154) is in the shape of a catheter.

25. The device according to claim 23, wherein the channel element (54; 154) is slot-shaped.

26. An apparatus as claimed in claim 23, wherein the channel element (54; 154) comprises a first channel portion (54 a; 154a) and a second channel portion (54 b; 154b) communicating with each other.

27. Apparatus according to claim 26, wherein said first passage portion (54 a; 154a) is obtained on said collection device (9) and said second passage portion (54 b; 154b) is obtained on said containing device (2).

28. The device according to claim 1, wherein said spring-operated regulating valve (17; 117) regulates the pressure of said fluid inside said containing means (2) to a relative pressure value ranging from about 0.01 to 6 bar.

29. The device according to claim 28, wherein said spring-operated regulating valve (17; 117) regulates said pressure of said fluid inside said containing means (2) to within a relative pressure value range of about 0.2-1 bar.

30. The device of claim 29, wherein said spring-operated regulating valve (17; 117) regulates said pressure of said fluid inside said containing means (2) to a relative pressure value in the range of about 0.3-0.8 bar.

31. Device according to any one of claims 28 to 30, wherein said spring-operated regulating valve (17; 117) regulates said pressure within said range of values when the device uses coffee powder having a predetermined granulometry.

32. The apparatus of claim 31, wherein the particle size comprises statistically distributed values according to a multimodal distribution.

33. The apparatus of claim 32, wherein the distribution has an average value of about 500 to 200 μ ι η.

34. The apparatus of claim 32, wherein the distribution has a median value of about 500 to 100 μ ι η.

35. The apparatus of any one of claims 32, wherein the distribution has a most common value of about 700 to 500 μ ι η.

36. The apparatus according to claim 1, wherein the delivery device (5, 10) comprises a delivery catheter (10).

37. Apparatus according to claim 36, wherein said delivery duct (10) comprises a base (20) fixed to a bottom (90) of said collection device (2).

38. The apparatus of claim 37, wherein the delivery conduit (10) further comprises a delivery portion (21) extending from the base (20) in a direction opposite the bottom (90).

39. Apparatus according to claim 38, wherein said conveying conduit (10) is arranged along a longitudinal axis of said collection device (9).

40. The apparatus according to claim 1, further comprising heating means able to heat said extraction fluid inside said containing means (2).

41. An apparatus for preparing a coffee beverage (C), comprising: containing means (2) for heating an extraction fluid, delivery means (5, 10, 110) arranged to make said fluid flow through a dose (W) of coffee and to send said extracted beverage (C) to collection means (9), characterized in that said apparatus comprises pressure regulating valve means (16; 17) arranged to inhibit said flow when said fluid contains a substantially vapour phase, said pressure regulating valve means (16; 17) being associated with said delivery means (5, 10, 110) and being selected from gravity-operated valves (16) or spring-operated valves (17).

42. The apparatus according to claim 41, wherein said pressure regulating valve means (16; 17) are associated with a portion (10; 110) of said delivery means (5, 10, 110) in which said extracted coffee beverage (C) flows.

43. The apparatus of claim 42, wherein the portion (10; 110) of the delivery device (5, 10, 110) comprises a delivery catheter (10; 110).

44. The device according to any of claims 41 to 43, further comprising venting means (32, 30, 33, 35, 132, 130) arranged to put the containing means (2) in communication with the external environment.

45. An apparatus as claimed in claim 43, wherein said pressure regulating valve means (16; 17) are associated with an end portion (10 a; 110a) of said delivery duct (10; 110).

46. An apparatus as claimed in claim 45, wherein said pressure regulating valve means (16; 17) are aligned on said end portion (10 a).

47. An apparatus as claimed in claim 45, wherein said pressure regulating valve means (16; 17) are located laterally of said end portion (110 a).

48. An apparatus as claimed in claim 44, wherein said venting means (32, 30, 33, 35, 132, 130) comprise gap means (30; 130) associated with said delivery duct (10; 110).

49. An apparatus as claimed in claim 48, wherein said gap means (30; 130) comprise an air vent gap (30; 130), said air vent gap (30; 130) being located between said delivery duct (10; 110) and a housing (31; 131) externally fixed to said delivery duct (10; 110).

50. A device as claimed in claim 49, wherein said housing (31; 131) is connected in shape with said delivery duct (10; 110).

51. The apparatus of claim 49, wherein the housing (131) only partially encloses the delivery catheter (110).

52. Apparatus according to claim 48, wherein said venting means (32, 30, 33, 35, 132, 130) comprise a passage element (32; 132), said passage element (32; 132) being located between said gap means (30; 130) and said containing means (2) so as to place said gap means (30; 130) and said containing means (2) in communication with each other.

53. An apparatus as claimed in claim 52, wherein the channel element (32; 132) is in the shape of a catheter.

54. An apparatus as claimed in claim 52, wherein the channel element (32; 132) is slot-shaped.

55. An apparatus as claimed in claim 52, wherein the channel element (32; 132) comprises a first channel portion (32 a; 132a) and a second channel portion (32 b; 132b) communicating with each other.

56. Apparatus according to claim 55, wherein said first passage portion (32 a; 132a) is obtained on said collection device (9) and said second passage portion (32 b; 132b) is obtained on said containing device (2).

57. An apparatus as claimed in claim 49, wherein said pressure regulating valve means (16; 17) communicates with said vent gap (30; 130).

58. Apparatus according to claim 49, wherein said pressure regulating valve means (17) is housed within said vent gap (130).

59. Apparatus according to claim 48, wherein said venting means (32, 30, 33, 35, 132, 130) comprises a chamber (33) and said delivery duct (10) comprises an end portion (10a), said chamber (33) being close to said end portion (10a) of said delivery duct (10) and communicating with said venting gap (30).

60. An apparatus as claimed in claim 59, wherein the end portion (10a) comprises an outlet duct (18) adjacent to the chamber (33), the outlet duct (18) being arranged transversely to the delivery duct (10).

61. An apparatus as claimed in claim 60, wherein the aeration conduit (18) is provided with at least one end opening (18b) and communicates with the delivery conduit (10) through a communication hole (210b) so as to place the delivery conduit (10) in communication with the collecting device (9).

62. An apparatus as claimed in claim 45, wherein on said end portion (110a) there is an outlet hole (19) arranged to put said delivery duct (110) in communication with said collecting device (9).

63. An apparatus as claimed in claim 45, wherein the delivery duct (10; 110) comprises a base (20; 120) fixed to the bottom (90) of the collecting device (2).

64. An apparatus as claimed in claim 63, wherein the delivery duct (10; 110) further comprises a delivery portion (21; 121) extending from the base (20; 120) in a direction opposite to the bottom (90).

65. Apparatus according to claim 64, wherein said conveying portion (21; 121) is arranged parallel to the longitudinal axis of said collection device (9).

66. An apparatus as claimed in claim 45, wherein said end portion (10 a; 110a) of said delivery duct (10; 110) is positioned close to cover means (14) arranged to selectively open and/or close said collecting means (9).

67. Apparatus according to claim 44, wherein said venting means (32, 30, 33, 35, 132, 130) comprise at least one outlet hole (35) obtained on said collecting means (9).

68. Apparatus according to claim 67, wherein said at least one outlet hole (35) is obtained on cover means (14) arranged to selectively open and/or close said collection means (9).

69. An apparatus as claimed in claim 67, wherein said pressure regulating valve means (16; 17) comprises a spring-operated valve (17), said spring-operated valve (17) being arranged in the vicinity of said at least one outlet opening (35).

70. Apparatus according to claim 69, wherein said venting means (32, 30, 33, 35, 132, 130) comprises a chamber (33) and said spring-operated valve (17) is arranged between said at least one outlet hole (35) and said chamber (33).

71. Apparatus according to claim 41, wherein said gravity-operated valve (16) is housed in a recess (15a) located on a portion (75) of said collection means (9).

72. An apparatus as claimed in claim 71, wherein the gravity operated valve (16) comprises a body (16a) having an airway tube (34) therein.

73. Apparatus according to claim 72, further comprising venting means (32, 30, 33, 35, 132, 130) arranged to put said containing means (2) in communication with the external environment, wherein said venting means (32, 30, 33, 35, 132, 130) comprise a chamber (33) and the end of said venting duct (34) is in communication with said chamber (33).

74. Apparatus as claimed in claim 72, wherein said gravity-operated valve (16) is provided with a shutter element (16b) associated with said body (16a) and arranged to selectively open and/or close said discharge conduit (34).

75. A method according to claim 74, wherein said shutter member (16b) is located between said body (16a) and said recess (15 a).

76. The apparatus of claim 41, wherein said pressure regulating valve means (16; 17) regulates the pressure of said fluid inside said containing means (2) to a relative pressure value in the range of about 0.01-6 bar.

77. The apparatus of claim 41, wherein said pressure regulating valve means (16; 17) regulates the pressure of said fluid inside said containing means (2) to a relative pressure value in the range of about 0.2-1 bar.

78. The apparatus of claim 41, wherein said pressure regulating valve means (16; 17) regulates the pressure of said fluid inside said containing means (2) to a relative pressure value in the range of about 0.3-0.8 bar.

79. Apparatus according to claim 41, wherein said pressure regulating valve means (16; 17) regulates said pressure within said range of values when said apparatus uses coffee powder having a predetermined granulometry.

80. The apparatus of claim 79, wherein the particle size comprises statistically distributed values according to a multimodal distribution.

81. The apparatus of claim 80, wherein the distribution has an average value of about 500 to 200 μm.

82. The apparatus of claim 80, wherein the distribution has a median value of about 500 to 100 μm.

83. The apparatus of claim 80, wherein the distribution has a most common value of about 700 to 500 μm.

84. The apparatus according to claim 41, further comprising heating means able to heat said extraction fluid inside said containing means (2).

85. An apparatus for preparing a coffee beverage, comprising: -containing means (2) for heating an extraction fluid, -conveying means (5, 7) for flowing said fluid through a dose (W) of coffee, characterized in that said apparatus comprises pressure regulating valve means (4; 4 ') arranged to inhibit said flow when said fluid contains a substantially vapour phase, said pressure regulating valve means (4; 4') being arranged to regulate the pressure of said fluid inside said containing means (2) and being different from overpressure regulating valve means comprised in said apparatus, said pressure regulating valve means (4; 4 ') being selected from a regulating valve (4) or an electronic regulating valve (4').

86. Apparatus according to claim 85, wherein said pressure regulating valve means (4; 4') regulates the pressure of said fluid inside said containing means (2) to a relative pressure value ranging from about 0.01 to 5 bar.

87. The apparatus of claim 86, wherein said pressure regulating valve means (4; 4') regulates the pressure of said fluid inside said containing means (2) to a relative pressure value in the range of about 0.1-2.5 bar.

88. Apparatus according to claim 87, wherein said pressure regulating valve means (4; 4') regulates the pressure of said fluid inside said containing means (2) to a relative pressure value in the range of about 0.2-1 bar.

89. Apparatus according to claim 88, wherein said pressure regulating valve means (4; 4') regulate the pressure of said fluid inside said containing means (2) to a relative pressure value ranging from about 0.5 to 0.7 bar.

90. Apparatus according to claim 85, further comprising safety means arranged to maintain the pressure of said fluid inside said containing means (2) below a set threshold value.

91. An apparatus as claimed in claim 85, wherein said pressure regulating valve means (4; 4') are provided on an outer surface portion of said apparatus (1).

92. An apparatus as claimed in claim 85, wherein said pressure regulating valve means (4; 4') are provided on a side face (2a) of said containing means (2).

93. The apparatus of claim 85, further comprising a venting pipe arrangement (40) arranged to receive the vapour vented by the pressure regulating valve arrangement (4; 4').

94. Apparatus according to claim 93, wherein said venting pipe means (40) is positioned on another external surface portion of said apparatus (1).

95. The apparatus of claim 85, further comprising collecting means (3) arranged to collect the coffee beverage (C) produced by the apparatus (1).

96. An apparatus as claimed in claim 85, wherein said pressure regulating valve means (4; 4') are arranged inside said apparatus (1).

97. An apparatus as claimed in claim 95, wherein said pressure regulating valve means (4; 4') are located in a region (91; 96) of the bottom (90) of said collecting means (3).

98. Apparatus according to claim 96, wherein said pressure regulating valve means (4; 4 ') comprises diffusing means (100) arranged to diffuse the vapour emitted by said pressure regulating valve means (4; 4') into said beverage (C).

99. The apparatus of claim 98, wherein the dispersing means comprises dispersing means (100) arranged to generate foam in the beverage (C).

100. The apparatus of claim 99, wherein said dispersion device (100) is selected from the group consisting of porous materials, porous baffles, slit baffles, perforated elastic membranes, sintered glass baffles, dispersion holes, dispersion nozzles.

101. An apparatus according to claim 95, further comprising conduit means (93) arranged to receive steam from said pressure regulating valve means (4; 4') and to convey said steam to another portion of said collecting means (3).

102. Apparatus according to claim 101, wherein said pressure regulating valve means (4; 4') is located in a zone (91; 96) of the bottom (90) of said collecting means (3) and said conduit means (93) is remote from said zone (91).

103. Apparatus according to claim 101, wherein said pressure regulating valve means (4; 4') is arranged in an upper portion (95) of said conduit means (93).

104. An apparatus as claimed in claim 85, wherein said pressure regulating valve means (4; 4 ') comprise solenoid valve means (4') for regulating the pressure inside said containing means (2).

105. Apparatus according to claim 104, further comprising control system means (200) arranged to control the operation of said solenoid valve means (4').

106. Apparatus according to claim 105, wherein said control system means (200) comprises sensor means (201) arranged to detect the pressure of said extraction fluid inside said containment means (2).

107. An apparatus according to claim 106, wherein said control system means (200) comprises amplifier means (202) arranged to amplify a pressure signal received by said sensor means (201).

108. An apparatus according to claim 107, wherein said control system means (200) comprises microprocessor means (203) arranged to compare said pressure signal received from said amplifier means (202) with a suitable comparison value and to send a command to control means (204) by acting on said pressure regulating valve means (4').

109. The apparatus as claimed in any one of claims 105-108, further comprising a receiving device arranged to receive the control system device (200).

110. A device according to claim 85, wherein the pressure regulating valve means (4; 4') co-operate with signalling means arranged to send an alarm signal to a user of the device.

111. An apparatus as claimed in claim 85, further comprising switching means arranged to switch the apparatus on and/or off.

112. The apparatus of claim 85, further comprising a heating device arranged to heat the extraction fluid.

113. A method for obtaining a coffee beverage, comprising: heating an extraction fluid for extracting said beverage so as to direct said fluid flow through a dose (W) of coffee, characterized in that, when said fluid contains a substantially vapour phase, said flow is inhibited by suitably adjusting the pressure of said extraction fluid prior to said flow, said adjustment being obtained by a pressure regulating valve means (4; 4 ') different from an overpressure regulating valve means, said pressure regulating valve means (4; 4 ') being selected from a regulating valve (4) or an electronic regulating valve (4 ').

114. The method of claim 113, further comprising introducing said extraction fluid into a containment device (2) prior to said heating.

115. The method of claim 113, wherein said adjusting comprises discharging a set amount of steam from said containment device (2).

116. A method as claimed in claim 113, wherein said venting comprises opening said pressure regulating valve means (4; 4').

117. A method as claimed in claim 113, wherein said regulation comprises closing said pressure regulating valve means (4; 4') when the pressure of said extraction fluid inside said containing means (2) reaches a set lower limit value.

118. The method of claim 113, wherein said regulating comprises maintaining a relative pressure inside said containing means (2) within a relative pressure value range of between about 0.01 and 5bar by means of said pressure regulating valve means (4; 4').

119. The method of claim 118, wherein said regulating comprises maintaining said relative pressure inside said containing means (2) within a relative pressure value range of between about 0.1 and 2.5bar by means of said pressure regulating valve means (4; 4').

120. The method of claim 119, wherein said regulation comprises maintaining said relative pressure inside said containing means (2) within a relative pressure value range of between about 0.2 and 1bar, through said pressure regulating valve means (4; 4').

121. The method of claim 120, wherein said regulation comprises maintaining said relative pressure inside said containing means (2) within a relative pressure value range of between about 0.5 and 0.7bar by means of said pressure regulating valve means (4; 4').

122. The method according to claim 113, further comprising regulating said pressure of said fluid inside said containment device (2) by means of said overpressure regulating device.

123. Method according to claim 113, wherein adjusting said pressure of said extraction fluid comprises discharging a set amount of steam from said containing means (2) outside the apparatus (1) for preparing the coffee beverage (C) through said pressure regulating valve means (4; 4').

124. Method according to claim 113, wherein regulating said pressure of said extraction fluid comprises discharging a set amount of steam from said containing means (2) to the inside of the apparatus (1) for preparing the coffee beverage (C) through said pressure regulating valve means (4; 4').

125. Method according to claim 113, wherein regulating said pressure of said extraction fluid comprises discharging a set amount of steam from said containing means (2) through said pressure regulating valve means (4; 4') inside collecting means (3) of the coffee beverage (C) contained in the apparatus (1) for preparing said coffee beverage (C).

126. The method of claim 125, wherein said venting comprises introducing said steam into said coffee beverage (C).

127. The method of claim 126, wherein said discharging comprises generating foam within said coffee beverage (C).

128. The method of claim 113, wherein said adjusting comprises electronically adjusting said pressure of said fluid within said containment device (2) by an electronic control system (200).

129. The method of claim 128, further comprising detecting the pressure value of the fluid within the containment device (2).

130. The method of claim 129, further comprising comparing the pressure value of the fluid detected within the containment device (2) with an appropriate comparison pressure value.

131. The method of claim 130, further comprising sending a command signal to said pressure regulating valve means (4') after said comparison when said pressure value of said fluid detected inside said containing means (2) is higher than said comparison value.

132. The method of claim 128, further comprising housing said electronic control system (200) within an apparatus (1) for producing a coffee beverage (C).

133. The method of claim 113, wherein the suppressing further comprises sending an alarm signal to a user.

134. The method of claim 113, wherein the heating comprises absorbing heat from a resistive device arranged to generate the heat.