Coffee brewing equipment

Abstract

The invention relates to a fully automatic coffee machine (100) comprising: a brewing chamber (1), an upper piston (2), a lower piston (3) which can be moved within the brewing chamber (1), the brewing chamber and / or the upper piston is relatively movable between a first closed position configured to compact coffee during brewing and a second closed position configured to not compact coffee during brewing; -a pressurized hot water fluid system comprising at least a water supply system (101), a water heating device (104) and a water pump (102), where the system is connected to the water inlet (13) of the coffee extraction unit, where the fluid supply system comprises a pressure bypass valve (107) downstream of the water pump, and where the fluid supply system comprises a pressure bypass valve (107) downstream of the water pump. The predetermined threshold pressure of the fluid dispensed by said pressure bypass valve is adjustable, and wherein the fully automatic coffee machine comprises a control system configured to:-move the brewing chamber and / or the upper piston to the first closed position or the second closed position for brewing coffee powder; and-adjusting a predetermined threshold pressure of the fluid dispensed by the pressure bypass valve to a first predetermined threshold pressure and a second predetermined threshold pressure, respectively, when the brewing chamber and / or the upper piston are moved to the first closed position and the second closed position, respectively.

Description

Technical Field

[0001] The present invention relates to a device for preparing coffee beverages. In particular, the present invention relates to a fully automatic coffee device. Background Art

[0002] Fully automatic coffee machines are configured to prepare coffee in an automatic manner, firstly, to prepare pressurized coffee, for example, espresso, ristretto, extended coffee, Americano, etc.

[0003] To this end, usually, in a fully automatic coffee machine, pressurized coffee is prepared in a brewing chamber configured to receive a certain amount of roasted and ground (R&G) coffee powder, compress the certain amount of coffee by means of at least one movable piston, and introduce pressurized water through the compressed coffee powder to extract the coffee. Finally, the extracted coffee beverage flows out from the outlet of the brewing chamber into a beverage cup.

[0004] Coffee consumers demand more and more variety and want to drink other types of coffee besides pressurized coffee, in particular so-called drip or filter coffee, which is a long cup of coffee prepared by contacting R&G coffee powder with hot water under low pressure. There is a need for a fully automatic machine capable of preparing both pressurized and filter coffee.

[0005] There are different solutions to meet this need.

[0006] Some fully automatic coffee machines offer an external accessory, such as a coffee pot (EP3669715) or a specific coffee chamber (DE102018125703), which is configured to contain R&G coffee powder and pass the hot water dispensed from the machine through the accessory and the coffee powder. However, the handling of such an accessory is cumbersome for the operator: the accessory must be manually filled with coffee powder, the accessory is manually attached to the water dispensing outlet of the machine, and finally, the extracted coffee must be removed and the accessory cleaned manually.

[0007] Other fully automatic machines make it possible to prepare pressurized or filtered coffee by controlling the movement of a piston in a chamber of the fully automatic machine.

[0008] JP2002183827 proposes controlling the movement of a piston so as to extract coffee with uncompressed coffee powder when filtered coffee is selected, and controlling the movement of the piston so as to compress the coffee powder when pressurized coffee is selected.

[0009] US2014150664, WO2014119414 and EP3253263 disclose a similar method.

[0010] In these prior art, there is no interest in providing the importance of adjusting the pressure of the water to the type of coffee being prepared in the brewing chamber. It appears that the pressure used to prepare filtered coffee is more a result of the size of the chamber set by the position of the piston than the choice of a specific pressure of the water to be introduced into the chamber.

[0011] As a result, the preparation of filtered coffee is not optimal.

[0012] One solution is to provide pressurized hot water from an adjustable flow pump that is controlled to provide water at different pressures, as in EP1267685, or to provide the brewing chamber with two different coffee beverage outlets that are configured to open at different pressure thresholds, as in US2014150664. However, such implementations are complex and expensive.

[0013] The purpose of the present invention is to solve the above-mentioned problems. Summary of the invention

[0014] In a first aspect of the present invention, there is provided a fully automatic coffee machine, the machine comprising:

[0015] - a coffee extraction unit, said coffee extraction unit comprising:

[0016] a brewing chamber for receiving roasted and ground coffee powder, the chamber comprising an upper edge and a bottom wall, and

[0017] .Upper piston,

[0018] The upper piston is configured to be movable across the upper edge of the brewing chamber and further movable within the brewing chamber to move the brewing chamber and the upper piston relative to each other, and

[0019] .Water inlet,

[0020] .Liquid outlet conduit,

[0021] . A lower piston movable within the brewing chamber between:

[0022] a lowest position, in which the lower piston rests on the bottom wall of the brewing chamber, and

[0023] . the uppermost position, in which the lower piston is located at the upper edge of the brewing chamber,

[0024] .Coffee grounds discharge device,

[0025] .Wherein, the brewing chamber and / or the upper piston can move relatively between the following positions:

[0026] . an open position for introducing roasted and ground coffee or discharging extracted roasted and ground coffee; and

[0027] at least two different first closed positions and second closed positions, the at least two different first closed positions and second closed positions being configured for brewing roasted and ground coffee powder, wherein the first closed position is configured for compacting the coffee during brewing and the second closed position is configured for not compacting the coffee during brewing,

[0028] - a pressurized hot water fluid system comprising at least a water supply system, a water heating device and a water pump, wherein said system is connected to a water inlet of a coffee extraction unit, wherein the fluid supply system comprises a pressure bypass valve downstream of the water pump, and wherein a predetermined threshold pressure of the fluid dispensed by said pressure bypass valve is adjustable, preferably by a motorized actuator, and

[0029] The fully automatic coffee machine includes a control system, which is configured as follows:

[0030] - moving the brewing chamber and / or the upper piston to a first closed position or a second closed position for brewing roasted and ground coffee powder, and

[0031] - adjusting the predetermined threshold pressure of the fluid dispensed by the pressure bypass valve to a first predetermined threshold pressure and a second predetermined threshold pressure, respectively, when the brewing chamber and the upper piston are in the first closed position and the second position, respectively.

[0032] The coffee extraction unit comprises a brewing chamber designed and oriented along a longitudinal axis. The axis can be oriented substantially vertically, or inclined relative to the vertical, or even oriented substantially horizontally.

[0033] The brewing chamber defines an internal volume configured to receive a dose of roasted and ground coffee powder, preferably roasted and ground coffee, to be extracted. Typically, the chamber is cylindrical with a side wall extending upwardly from a bottom wall to an upper edge. The longitudinal axis of the cylindrical shape is preferably oriented substantially vertically.

[0034] The top of the brewing chamber is open to enable the introduction of coffee powder to be extracted.

[0035] The extraction unit comprises a water inlet configured to introduce water into the interior of the chamber to extract coffee powder present in the chamber.

[0036] The coffee machine comprises two pistons movable through the interior volume of the chamber.

[0037] The first piston is movable through the upper part of the chamber and is referred to as the upper piston. The upper piston is designed to be movable through the upper edge of the brewing chamber and further move within the brewing chamber to move the brewing chamber and the upper piston relative to each other. The upper piston is designed so that the coffee powder present inside the chamber can be compressed, and therefore, the upper piston is also referred to as a compression piston.

[0038] The second piston is referred to as the lower piston. The lower piston is movable in the brewing chamber between two end positions. One end position is the lowest position of the second piston in the chamber. In this lowest position, the head of the lower piston is located on the bottom wall of the brewing chamber. Typically, the lower piston is positioned in this lower position during the operation of introducing coffee powder into the chamber and during the operation of extracting coffee powder with water.

[0039] The other end position is the highest position of the second piston in the chamber. In this higher position, the upper surface of the head of the lower piston is at the upper edge of the brewing chamber. Typically, during the operation of discharging the extracted coffee powder from the chamber, the lower piston is positioned at this higher position.

[0040] The lower piston includes a head and a rod, and therefore, the lower piston is also called a compression piston.

[0041] The lower piston includes a head and a rod.

[0042] The lower piston is assembled to the brewing chamber so that its piston rod extends through an opening in the bottom wall of the brewing chamber, with the bottom free end of the rod being located outside the chamber. The piston rod is configured to move up and down within the opening.

[0043] The extraction unit comprises a liquid outlet conduit. The conduit is capable of dispensing the extracted beverage, preferably coffee, from the chamber. Typically, the conduit extends from the piston to a nozzle for dispensing the beverage in a cup.

[0044] The coffee extraction unit may be configured to perform a top-down extraction (gravity extraction) or to perform a bottom-up extraction (anti-gravity extraction).

[0045] In units configured for bottom-up extraction, water is introduced through the bottom of the chamber, and the extracted coffee is dispensed through the top of the chamber. In general, for a bottom-up configuration:

[0046] - The water inlet is positioned inside the side wall of the chamber, preferably close to the bottom wall.

[0047] - the head of the lower piston presents water openings configured to introduce water from the water inlet upwards into the coffee powder present inside the chamber,

[0048] - The upper piston comprises a liquid outlet conduit.

[0049] In units configured for top-down extraction, water is introduced through the top of the chamber, and the extracted coffee is distributed through the bottom of the chamber. Typically, for a top-down configuration:

[0050] -The water inlet is located in the upper piston,

[0051] - the head of the upper piston presents a water opening configured to introduce water from the water inlet downwards and into the coffee powder present inside the chamber,

[0052] - The lower piston comprises a liquid outlet conduit.

[0053] The machine comprises a supporting frame on which a brewing chamber is mounted.

[0054] The relative movement of the brewing chamber and the two pistons can be achieved indifferently in the following ways:

[0055] - keeping the brewing chamber fixed to the support frame and actuating the piston inside and / or outside the chamber,

[0056] and / or

[0057] - Actuation of the brewing chambers relative to the support frame, while the pistons remain fixed or are passively driven by the movement of the chambers that hold them.

[0058] In a preferred embodiment, the brewing chamber can be moved by a drive member. The drive member can be a rack or any other known member.

[0059] In this embodiment, preferably:

[0060] - The upper piston is fixed,

[0061] - the rod of the lower piston comprises a free bottom end located outside the brewing chamber and movable together with said piston and said chamber,

[0062] - the device comprises a fixed bottom stop wall capable of contacting the bottom end of the rod of the lower piston,

[0063] The movement of the lower piston depends on the movement of the brewing chamber and / or the contact of the free bottom end with the lower stop wall or the contact of the lower piston with the upper piston.

[0064] Preferably, in this preferred embodiment, the lower piston is free of guiding means, retaining means and springs, which means that the lower piston is passive and has no active means to change the position of the lower piston relative to the brewing chamber.

[0065] Preferably, in this preferred embodiment, the rod and / or the lower piston are provided with friction components to control the movement of the rod and / or the lower piston relative to the inner wall of the brewing chamber. These components enable the lower piston to remain in one position relative to the brewing chamber.

[0066] In an alternative embodiment, the brewing chamber may be fixedly mounted in the machine and the upper and lower pistons may be movable inside and outside the brewing chamber by means of drive means.

[0067] The coffee extraction unit comprises a discharge device for the extracted coffee powder (coffee cake). The discharge device is designed to sweep the area above the upper edge of the chamber by any rotational or translational movement when the lower piston is in its uppermost position.

[0068] The fully automatic coffee machine comprises a pressurized hot water fluid system, which comprises at least a water supply system, a water heating device and a water pump. The system is connected to the water inlet of the coffee extraction unit. Thus, hot pressurized water is supplied to the brewing chamber for extracting roasted and ground coffee powder.

[0069] Furthermore, the fluid supply system comprises a pressure bypass valve. The pressure bypass valve is located downstream of the water pump, which means that the outlet of the pump dispensing the pumped fluid is connected to the inlet of the valve. The pressure bypass valve determines the pressure of the water distributed to the coffee extraction unit. This predetermined threshold pressure of the fluid distributed by said pressure bypass valve is adjustable, preferably by a motorized actuator.

[0070] Typically, a fully automatic coffee machine includes a control system configured to:

[0071] - actuating the movement of the brewing chamber and / or the piston,

[0072] - means for controlling the pressurized hot water fluid system, ie at least the water heating device, the water pump and the actuator of the pressure bypass valve.

[0073] The actuator thus provides a simple implementation to enable the water pressure to be adjusted during coffee extraction and in particular according to the type of coffee preparation (pressed coffee or filtered coffee).

[0074] Additionally, the control system is configured to enable the brewing chamber and / or the upper piston to move relative to each other between the following positions:

[0075] - an open position for introducing roasted and ground coffee or for discharging roasted and ground coffee after extraction; and

[0076] - at least two different first and second closed positions, the at least two different first and second closed positions being configured for brewing roasted and ground coffee powder.

[0077] In the first closed position of the brewing chamber and the upper piston, the coffee is compacted during brewing, which enables the preparation of pressurized coffee. Depending on the amount and / or volume of coffee introduced into the chamber, the brewing chamber and / or the upper piston can be relatively moved to different first closed positions, thereby enabling the compaction of the introduced coffee.

[0078] On the contrary, in the second closed position of the brewing chamber and the upper piston, the coffee is not compacted during brewing, which enables the preparation of filtered coffee. During extraction, the coffee powder remains loose in the brewing chamber.

[0079] Preferably, this second closed position of the brewing chamber defines a maximum possible closed volume of the brewing chamber.

[0080] Finally, the control system is configured to set a predetermined threshold pressure of the fluid distributed by the pressure bypass valve to:

[0081] - when the brewing chamber and / or the upper piston moves to a first closed position, regulating to a first predetermined threshold pressure,

[0082] as well as

[0083] - When the brewing chamber and / or the upper piston is moved to a second closed position, a second predetermined threshold pressure is adjusted.

[0084] The machine is therefore able to optimally prepare either pressurized coffee or filtered coffee, as the key parameters of pressure and compression are met for each type of preparation.

[0085] Preferably, the first predetermined threshold pressure is greater than 4 bar and the second predetermined threshold pressure is less than 4 bar.

[0086] In a preferred embodiment, the coffee extraction unit comprises a coffee outlet valve, and the valve is configured to distribute liquid from the liquid outlet conduit to the coffee dispensing area or the waste collector.

[0087] Upon actuation of the valve, a portion of the beverage dispensed from the brewing chamber can be sent to a waste collector. This is particularly useful during the preparation of filtered coffee, since the last portion of the coffee usually includes a lot of residues and this last portion can be diverted from the drinking cup.

[0088] In a particular embodiment, the coffee outlet valve is actuable by movement of the brewing chamber.

[0089] Preferably, the machine comprises a single tank for storing coffee beans and a grinder for grinding the stored coffee beans and for dispensing the roasted and ground coffee in the brewing chamber.

[0090] In fact, this machine enables the preparation of filtered coffee or pressurized coffee from the same roasted and ground coffee powder. There is no need to adjust the granulometry size of the powder or the type of coffee beans (roasting level) according to the type of coffee prepared. The following facts:

[0091] - adjust the pressure, and

[0092] - Compaction is achieved or not, sufficient to provide an optimal preparation from the same roasted and ground coffee powder.

[0093] In a second aspect of the present invention, there is provided a method for preparing a coffee beverage using a fully automatic coffee apparatus such as described above, wherein the method comprises the following steps:

[0094] α- obtaining a beverage selection input from a user regarding a preparation type of coffee from a list of at least pressurized coffee and filtered coffee,

[0095] β- adjusting the predetermined threshold pressure of the bypass pressure valve to a first predetermined threshold pressure for pressurized coffee or to a second predetermined threshold pressure for filtered coffee based on the beverage selection input of step α,

[0096] a- in the dosing position, in which the upper piston is at a distance from the upper edge of the chamber and outside the chamber, a dose of roasted and ground coffee powder corresponding to the beverage selection input is supplied into the brewing chamber, then,

[0097] b- based on the beverage selection input of step α, moving the chamber and the upper piston relative to each other to a first closed position for pressurized coffee or to a second closed position for filtered coffee, and then,

[0098] c- introducing hot water through the water inlet, extracting the coffee powder and dispensing the extracted coffee beverage through the beverage outlet of the upper piston,

[0099] e- Discharge the extracted coffee grounds from the chamber.

[0100] In a preferred embodiment of the method, if the beverage selection input of step a is filter coffee, then at the end of step c), the method comprises the following steps:

[0101] d1 - actuating the coffee outlet valve to dispense liquid from the liquid outlet conduit to the waste collector, and

[0102] d2-Moving the chamber and the upper piston relative to each other to tamp a dose of extracted coffee powder, and repeating this step at least once, preferably at least twice.

[0103] Preferably, in step d2), the chamber (1) and the upper piston (2) remain in the tamping position for one to three seconds.

[0104] Alternatively, if the beverage selection input of step a is pressurized coffee, then in step b) the dose of ground coffee is compressed by the chamber and the upper piston.

[0105] Typically, in step e), the chamber, the upper piston and the lower piston are moved relative to each other so as to:

[0106] . Position the upper edge of the chamber away from the upper piston, and

[0107] . Position the lower piston at the upper edge of the brewing chamber, and

[0108] .The extracted coffee powder is discharged from the lower piston.

[0109] In this application, the terms "interior", "top", "bottom" and "lateral" are used to describe the positional relationship of the features of the present invention. These terms should be understood to mean that when positioned in a fully automatic coffee machine for producing beverages, the device is in its normal orientation, as shown in the figures.

[0110] The above aspects of the present invention may be combined in any suitable combination. In addition, various features herein may be combined with one or more of the above aspects to provide combinations other than those specifically illustrated and described. Additional objects and advantageous features of the present invention will be apparent from the claims, specific embodiments, and accompanying drawings. DETAILED DESCRIPTION

[0111] - Figure 1A is a schematic side view of a fully automatic coffee machine including a bottom-up extraction chamber,

[0112] - Figure 1B yes Figure 1A A perspective view of some elements of the machine,

[0113] - Figure 2 yes Figure 1A to Figure 1B A magnified view of the brewing chamber.

[0114] - FIG. 3A to FIG. 3K Shown Figure 1A to Figure 1B Steps for preparing filtered coffee with a fully automatic coffee machine,

[0115] - Figure 4 yes Figure 1A to Figure 1BSchematic diagram of a preferred water fluid system of a fully automatic coffee machine,

[0116] - Figure 5 Yes Figure 4 Schematic diagram of the fluid system of a process control system of a fully automatic coffee machine.

[0117] - Figure 6 It is a schematic diagram of a pressure bypass valve in a fluid system.

[0118] Figure 1A is a side view of a fully automatic coffee machine 100 with the side panels removed to show the coffee extraction unit 10 and the coffee grounds supply. Figure 1B is a perspective view showing the other side of the machine 100 .

[0119] The coffee extraction unit 10 comprises a brewing chamber 1 for receiving a dose of roasted and ground coffee powder. The coffee is stored as beans in a tank 6. The tank provides a grinder 61 with the coffee beans so that a dose of roasted and ground coffee can be dispensed from the grinder outlet through a funnel 108 in the brewing chamber 1.

[0120] Preferably, the brewing chamber 1 is a cylinder with an open top, which extends along the axis XX' from the bottom 11 to the upper edge 12. The chamber 1 comprises a water inlet conduit (not shown), to which the water fluid line is connected. The water inlet conduit is preferably located close to the bottom of the chamber, such as inside the lower part of the side wall, or alternatively in the bottom wall.

[0121] The coffee extraction unit 10 comprises drive means to move the chamber 1 vertically and obliquely up and down and in reverse. The chamber may be positioned in a carrier 14 configured to slide along a guide shaft. The movement of this carrier may be achieved by a gearbox connecting the carrier to a motor. Any other embodiment may be achieved like a chamber mounted on a worm drive actuated by a motor means, the rotation of the worm causing a vertical translation of the chamber.

[0122] The coffee extraction unit 10 comprises an upper piston 2. The upper piston 2 has a lower end portion which exhibits a cylindrical design and has a diameter substantially equal to the diameter of the chamber, so that the upper piston can pass through the upper edge 12 of the chamber and move the brewing chamber further upwards in the direction of the upper piston inside the brewing chamber. Thus, the upper piston makes it possible to close the brewing chamber during coffee extraction and to compress a dose of roasted and ground coffee powder introduced inside the brewing chamber.

[0123] In addition, the upper piston 2 comprises a liquid outlet conduit 21 extending from the bottom surface of the upper piston and connected to the coffee dispensing nozzle 9 by an outlet pipe 112. In a preferred embodiment corresponding to the coffee machine shown, the liquid outlet conduit 21 can be connected to the coffee dispensing nozzle 9 or to an outlet line 110 leading to a waste collector via a coffee outlet valve 106. This preferred embodiment provides additional advantages in terms of the quality of the coffee beverage.

[0124] The coffee extraction unit 10 comprises Figure 2 The lower piston 3 is enlarged in the figure, and has a head 32, which includes a water outlet 34, which is configured for distributing water introduced through the water inlet conduit during coffee preparation. The head serves as a water distributor.

[0125] The head is disc-shaped and has a diameter substantially equal to the inner diameter of the chamber cylinder. The head forms the bottom wall of the chamber of the extraction unit. The lower piston 3 comprises a rod 31 fixed to the bottom of the disc-shaped head 32 and extending downwards. The piston 3 is assembled to the chamber, wherein the rod 31 extends below the bottom of the chamber.

[0126] The rod 31 of the lower piston has no guide elements, retaining elements or springs, wherein the lower piston is movable coaxially to the brewing chamber and within said brewing chamber.

[0127] The lower piston 3 is movable within the brewing chamber 1 between two end positions:

[0128] - lowest position, in which the lower piston rests on the bottom wall 11 of the brewing chamber ( Figure 2 ),and

[0129] - an upper position, in which the lower piston is located at the upper edge 12 of the brewing chamber ( Figure 3H ).

[0130] The coffee extraction unit 10 comprises: a discharge device 4 for cleaning the extracted coffee cake ( Fig. 3I ). The coffee extraction unit is positioned slightly above the upper edge of the brewing chamber. The cleaned coffee cake is stored in a waste collector.

[0131] In the embodiment shown, the upper piston 2 is fixed. The lower piston 3 can move coaxially:

[0132] - together with the brewing chamber 1, which means that when the brewing chamber 1 moves, the brewing chamber takes the lower piston with it, and

[0133] - in the brewing chamber 1, which means that the lower piston can be moved at different positions in the brewing chamber. When the brewing chamber moves upwards, the movement of the lower piston 3 in the brewing chamber is driven by the contact of its head 32 against the upper piston 2 and by the connection of its rod 31 with a cam (not shown). In particular when top-down extraction is achieved, any other mechanism from the prior art that enables relative movement of the chamber with the upper and lower pistons can be used.

[0134] The fully automatic coffee machine comprises a user interface (not shown) to enable the selection of the type of coffee, in particular filter coffee or pressurized coffee preparation.

[0135] The hardware of the user interface may include any suitable device, for example, the hardware includes one or more of the following: buttons (such as joystick buttons, knobs, or push buttons), joysticks, LEDs, graphic or character LCDs, graphic screens with touch sensing, and / or screen edge buttons.

[0136] When the fully automatic coffee machine is provided with a communication interface as described below, a part of the user interface may also be located on the mobile application. In this case, at least a part of the input and output may be transmitted to the mobile device via the communication interface.

[0137] Such a fully automatic coffee machine is capable of preparing pressurized coffee by implementing the following steps, which are well known in the prior art:

[0138] a- in the dosing position, in which the upper piston 2 is at a distance from the upper edge 12 of the chamber and outside the chamber, a dose of roasted and ground coffee powder corresponding to pressurized coffee preparation is supplied into the brewing chamber, then,

[0139] b- moving the chamber 1 and the upper piston 2 relative to each other to a first position, wherein:

[0140] .The upper opening of the chamber is closed, and

[0141] A certain dose of coffee powder is compressed between the lower piston 3 and the upper piston 2.

[0142] Then

[0143] c- hot water is introduced into the chamber, extracting the coffee powder and dispensing the extracted coffee through the beverage outlet 21 of the upper piston and then through the coffee dispensing nozzle 9 in the cup, then

[0144] e- The extracted coffee powder is discharged from the chamber by moving the chamber 1 away from the upper piston 2, so that the lower piston moves upwards in the chamber until the upper edge 12. In this position, the coffee cake can be swept by the discharge device 4 and collected in the waste collector.

[0145] The fully automatic coffee machine can also prepare coffee by performing the following steps: FIG. 3A to FIG. 3K Filter coffee shown in:

[0146] a-In dosing position ( Figure 3A ), wherein the upper piston 2 is at a distance from the upper edge 12 of the chamber and outside the chamber, a dose of roasted and ground coffee powder corresponding to the preparation of filtered coffee is supplied into the brewing chamber, and then,

[0147] b- moving the chamber 1 and the upper piston 2 relative to each other to a second position in which the upper opening of the chamber is closed ( Figure 3B ). However, a dose of coffee powder P is not compressed between the lower piston 3 and the upper piston 2. As a result, the coffee powder remains loose during beverage preparation, which is a key condition for preparing filtered coffee. Preferably, the chamber 1 and the upper piston 2 are positioned relative to each other so as to provide the widest internal volume while keeping the chamber closed.

[0148] c-Introduce hot water W into the chamber ( Figure 3C ), which has the effect of extracting coffee powder. When water fills the chamber volume, the extracted coffee filter is distributed through the beverage outlet 21 of the upper piston and then distributed through the coffee dispensing nozzle 9 in the cup ( Figure 3D ).

[0149] At the end of water introduction ( Figure 3E ), since the coffee powder is not compressed during extraction, a certain amount of liquid remains in the chamber. This extracted coffee and the remaining liquid form a kind of mud. Before preparing a new coffee, the chamber must be thoroughly cleaned. Then, at least the following steps are performed.

[0150] d2-Move the chamber 1 and the upper piston 2 relative to each other to tamp the coffee powder present in the chamber. During said operation, the liquid still present in the chamber is discharged through the outlet duct 21 of the upper piston. In a less preferred embodiment, this liquid escaping from the tamping operation can be distributed through the coffee nozzle 9 in the drinking cup and form part of the filtered coffee beverage. In this case, the final beverage may include some small solid residues, which are still acceptable for this type of coffee.

[0151] The position of the chamber where the tamping effect is obtained can be determined by the measure of the current supplied to the motor which actuates the chamber and stops the movement of the chamber when a preset threshold of current is reached.The tamping position can be detected using any alternative known means.

[0152] Preferably, the tamping is repeated at least once, preferably at least twice, by moving the chamber 1 away from the upper piston 2 and then moving the chamber and the upper piston relative to each other to tamp the coffee powder. In this second tamping operation, the chamber can only be moved slightly away from the upper piston, for example, by 10 mm or 20 mm; it is not necessary to move the chamber to its widest internal volume. This operation makes it possible to introduce air in the water inlet duct and to discharge stagnant water-coffee liquid residues, as a result of which the operation of drying the ground coffee and compacting the coffee cake will be improved.

[0153] Several tamping operations allow the coffee powder to be completely dried. Improved drying ensures better cleaning of the chamber, less residues remaining in the chamber, and better sweeping of the coffee cake 7 by the discharge device 4.

[0154] Depending on the type of coffee powder used, the coffee powder may present different hygroscopic properties that directly affect the facilities for drying the wetted powder. This property may depend on the roasting level, the nature of the coffee beans (Arabica, Robusta...), the grind size. Therefore, the number of tamping operations can be adapted to the coffee powder used.

[0155] e- The extracted coffee powder is discharged from the chamber by moving the chamber 1 away from the upper piston 2, so that the lower piston moves upwards in the chamber until the upper edge 12. In this position, the coffee cake can be swept by the discharge device 4 and collected in the waste collector 8 ( Figure 3G to Figure 3K ).

[0156] In a preferred embodiment, the fully automatic coffee machine comprises Figure 1A to Figure 1B and at the end of the introduction of water and the extraction of coffee (step c), the following steps are implemented in order to clean the chamber:

[0157] d1 - actuating the coffee outlet valve 106 to enable the distribution of liquid from the liquid outlet conduit 21 to the waste collector 8, and

[0158] d2-Move the chamber 1 and the upper piston 2 relative to each other in order to tamp the coffee powder present in the chamber. During said operation, the liquid still present in the chamber is discharged through the outlet duct 21 of the upper piston to the waste collector 8, as Figure 3F As shown. Thus, the dispensed liquid enriched with coffee residues is not dispensed in the final coffee filter beverage. Again, preferably, the cleaning of the chamber is improved by moving the chamber 1 away from the upper piston 2 and then moving the chamber and the upper piston relative to each other to tamp the coffee powder, repeating the tamping at least once, preferably at least twice.

[0159] This coffee outlet valve 6 can also be used to enable preheating of the chamber 1 with hot water before preparing coffee. Hot water can be introduced into the chamber for a sufficient time to heat its walls, and this water can then be distributed into the waste collector through the coffee outlet valve 6. Then, coffee preparation can begin.

[0160] The fully automatic coffee machine includes a water fluid system, such as Figure 4 As shown schematically in FIG.

[0161] The production line of the system includes at least:

[0162] - Water tank 101,

[0163] - pump 102,

[0164] - heater 104,

[0165] The end of the hot water fluid line is connected to the water inlet 13 of the brewing chamber part of the coffee extraction unit 10 .

[0166] Preferably, the fluid system may include a flow meter 103 for better control of the preparation.

[0167] Preferably, the fluid system may comprise a valve 105 to enable the pumped water to be distributed to another delivery point, in particular at a distribution area for ground coffee for preparing Americano coffee. In such a preparation, hot water is added directly to the cup of coffee dispensed from the brewing chamber.

[0168] In one embodiment, the fluid line may include a bypass line (shown in phantom) around the heater 104 so that water can be used for cold preparation. In this case, a cold brew coffee sample is obtained.

[0169] In addition, the system comprises a pressure bypass valve 107 downstream of the water pump 102. The pressure bypass valve comprises two check valves and is configured so that a predetermined threshold pressure of the fluid distributed by the pressure bypass valve is adjustable, preferably by a motorized actuator, for example, a gearbox 1075 connected to the motor M.

[0170] Figure 6 Such a pressure bypass valve 107 is schematically shown. The valve 107 comprises a first check valve 1073a between an inlet line 1071 for pumping water and an outlet line 1077 for distributing water to the heater. The valve 107 comprises a second check valve 1073b configured to adjust the maximum permissible pressure in the outlet line 1077.

[0171] The adjustment of the maximum permissible pressure is performed by controlling the tension of the spring of the second check valve 1073b. The tension is adjusted by an adjustable screw 1074. The valve 107 comprises a motor 24 and a gearbox 1075 to control the movement of the adjustable screw 1074 and to control the water pressure at the outlet line 1077 accordingly. An absolute position sensor 1076 may be provided to control the position of the screw. The valve 107 comprises a bypass line 1072 to divert a portion of the water from the outlet line 1077, if necessary, according to a predetermined threshold pressure that is adjusted. Preferably, the bypass line 1072 is connected to an upstream portion of a pump in the fluid system.

[0172] Thus, the fluid supply system can simply and quickly adjust the pressure of the water introduced into the extraction unit. This pressure can be adjusted each time a coffee is prepared and can in particular be different depending on whether a pressurized coffee or a filtered coffee is prepared.

[0173] In a simplest embodiment, the motor M is configured to adjust the screw 1074 between two positions: a first position corresponding to a pressure for preparing pressurized coffee, which pressure is typically higher than 4 bar, preferably higher than 7 bar; and a second position corresponding to a pressure for preparing filtered coffee, which pressure is typically lower than 4 bar.

[0174] Figure 5 Yes Figure 4 Schematic diagram of the fluid system of the control system of a fully automatic coffee machine.

[0175] The control system generally includes: a processing unit 111 , a power source 1111 , and a memory unit 1112 .

[0176] The processing unit 111 typically includes memory, input and output system components arranged as an integrated circuit, typically a microprocessor or microcontroller.The power source 1111 is operable to supply electrical energy to the controlled components and the processing unit.

[0177] Processing unit 111 typically includes a memory unit 1112 for storing instructions as program code and optionally data.

[0178] The instructions stored on the memory unit 112 can desirably comprise a program to adjust the internal volume of the chamber 1 and the predetermined threshold pressure of the fluid dispensed by the pressure bypass valve according to the type of coffee to be prepared based on input provided by the user interface 109 .

[0179] During preparation of a coffee beverage, the control system is operable to:

[0180] - obtaining a beverage selection input from a user regarding a preparation type of coffee from a list of pressurized coffee and filtered coffee,

[0181] - actuating the drive means of the chamber to move the brewing chamber and / or the upper piston to a first closed position for pressurized coffee input or to a second position for filtered coffee preparation, and

[0182] - Actuating the motor M of the pressure bypass valve to adjust the predetermined threshold pressure of the fluid dispensed by the pressure bypass valve to a first predetermined threshold pressure for pressurized coffee input or to a second predetermined threshold pressure for filtered coffee.

[0183] Although the present invention is described with a fully automatic coffee machine comprising an extraction unit based on bottom-up extraction, the same preparation method is applicable to an extraction unit based on top-down extraction.

[0184] Although the present invention has been described with reference to the above illustrated embodiments, it should be understood that the invention as claimed is not in any way limited to these illustrated embodiments.

[0185] Various changes and modifications may be made without departing from the scope of the invention as defined in the claims. In addition, where known equivalents exist for specific features, such equivalents shall be incorporated as if explicitly mentioned in this specification.

[0186] As used in this specification, the words "include", "comprises" and similar words should not be understood as having exclusive or exhaustive meanings. In other words, these words are intended to mean "including but not limited to".

[0187] List of references in the accompanying drawings :

[0188] Coffee extraction unit 10

[0189] Brewing chamber 1

[0190] Bottom 11

[0191] Upper edge 12

[0192] Water Inlet 13

[0193] Carrier 14

[0194] Upper piston 2

[0195] Outlet conduit 21

[0196] Lower piston 3

[0197] Piston rod 31

[0198] Head 32

[0199] Water inlet 33

[0200] Water outlet 34

[0201] Discharge device 4

[0202] Export pipe 5

[0203] Coffee bean can 6

[0204] Grinding machine 61

[0205] Coffee cake7

[0206] Waste collector 8

[0207] Dispensing nozzle 9

[0208] Coffee Machine 100

[0209] Water Tank 101

[0210] Pump 102

[0211] Flow meter 103

[0212] Heater 104

[0213] Valve 105

[0214] American coffee water line 1051

[0215] Coffee outlet valve 106

[0216] Pressure bypass valve 107

[0217] Inlet line 1071

[0218] Bypass line 1072

[0219] Check valves 1073a, 1073b

[0220] Adjustable screw 1074

[0221] Gearbox 1075

[0222] Position sensor 1076

[0223] Export pipeline 1077

[0224] Ground coffee funnel 108

[0225] User Interface 109

[0226] Outlet line 110 to waste collector

[0227] Processing unit 111

[0228] Power Source 1111

[0229] Memory unit 1112

[0230] Water

[0231] Roasted and ground coffee powder

[0232] Coffee Drinks C

[0233] Residue R

[0234] Motor M

Claims

1. A fully automatic coffee machine (100), comprising: - a coffee extraction unit (10), comprising: a brewing chamber (1) for receiving roasted and ground coffee powder, the chamber comprising an upper edge (12) and a bottom wall (11), and . Upper piston (2), the upper piston being configured to be movable across the upper edge of the brewing chamber and further movable within the brewing chamber to move the brewing chamber and the upper piston relative to each other, and . Water inlet (13), . Liquid outlet conduit (21), A lower piston (3) capable of moving within the brewing chamber (1) between the following positions: . a lowest position, wherein the lower piston is located at the bottom wall (11) of the brewing chamber, and . an uppermost position, wherein the lower piston is located at the upper edge (12) of the brewing chamber, . A device for discharging coffee grounds (4), .Wherein, the brewing chamber and / or the upper piston can move relatively between the following positions: . an open position for introducing roasted and ground coffee or discharging extracted roasted and ground coffee; and at least two different first closed positions and second closed positions, the at least two different first closed positions and second closed positions being configured for brewing roasted and ground coffee powder, wherein the first closed position is configured for compacting the coffee during brewing and the second closed position is configured for not compacting the coffee during brewing, - a pressurized hot water fluid system comprising at least a water supply system (101), a water pump (102) and preferably a water heating device (104), wherein said system is connected to said water inlet (13) of said coffee extraction unit, wherein the fluid supply system comprises a pressure bypass valve (107) downstream of the water pump, and wherein the predetermined threshold pressure of the fluid distributed by the pressure bypass valve is adjustable, preferably by a motorized actuator (1071), and Wherein, the fully automatic coffee machine includes a control system, and the control system is configured as follows: - moving the brewing chamber and / or the upper piston to the first closed position or the second closed position for brewing roasted and ground coffee powder, and - adjusting the predetermined threshold pressure of the fluid dispensed by the pressure bypass valve to a first predetermined threshold pressure and a second predetermined threshold pressure, respectively, when the brewing chamber and / or the upper piston are in the first closed position and the second closed position, respectively.

2. The fully automatic coffee machine (100) according to claim 1, wherein: The second closed position of the brewing chamber defines a maximum possible closed volume of the brewing chamber.

3. The fully automatic coffee machine (100) according to claim 1 or 2, wherein: The first predetermined threshold pressure is greater than 4 bar and the second predetermined threshold pressure is less than 4 bar.

4. The fully automatic coffee machine (100) according to any one of the preceding claims, wherein: - the brewing chamber comprises the water inlet (13), and - The upper piston (2) comprises a coffee outlet duct (21).

5. The fully automatic coffee machine (100) according to any one of the preceding claims, wherein: The coffee extraction unit comprises a coffee outlet valve (6) configured to distribute liquid from the liquid outlet conduit to a coffee dispensing area or a waste collector.

6. Fully automatic coffee machine (100) according to the preceding claim, wherein: The coffee outlet valve (106) is actuated by movement of the brewing chamber.

7. The fully automatic coffee machine (100) according to any one of the preceding claims, wherein: The machine comprises a tank (6) for storing coffee beans and a grinder (61) for grinding the stored coffee beans and for dispensing roasted and ground coffee in the brewing chamber (1).

8. Method for preparing a coffee beverage using a fully automatic coffee device according to any one of claims 1 to 6, wherein: The method comprises the following steps: α- obtaining a beverage selection input from a user regarding a preparation type of coffee from a list of at least pressurized coffee and filtered coffee, β- adjusting the predetermined threshold pressure of the bypass pressure valve to the first predetermined threshold pressure for pressurized coffee or to the second predetermined threshold pressure for filtered coffee based on the beverage selection input of step α, a- in a dosing position, wherein the upper piston (2) is at a distance from the upper edge (12) of the chamber and outside the chamber, a dose of roasted and ground coffee powder corresponding to the beverage selection input is supplied into the brewing chamber, then, b- based on the beverage selection input of step a, moving the chamber (1) and the upper piston (2) relative to each other into the first closed position for pressurized coffee or into the second closed position for filtered coffee, and then, c- introducing hot water through the water inlet (3), extracting the coffee powder and dispensing the extracted coffee beverage through the beverage outlet (21) of the upper piston, e- Discharging the extracted coffee powder from the chamber.

9. The method according to the preceding claim, wherein: If the beverage selection input of step α is filter coffee, then at the end of step c), the method comprises the following steps: d1- actuating the coffee outlet valve (106) to distribute liquid from the liquid outlet conduit to the waste collector (8), and d2-Moving the chamber (1) and the upper piston (2) relative to each other to tamp the dose of extracted coffee powder, and repeating the steps at least once, preferably at least twice.

10. The method according to the preceding claim, wherein: In step d2), the chamber (1) and the upper piston (2) remain in the tamping position for one to three seconds.

11. The method according to any one of claims 7 to 10, wherein: If the beverage selection input of step a is pressurized coffee, then in step b) the dose of coffee powder is compressed in the chamber (1) between the lower piston (3) and the upper piston (2).

12. The method according to any one of claims 7 to 11, wherein: In step e), the chamber (1), the upper piston (2) and the lower piston (3) are moved relative to each other so as to: . positioning the upper edge (12) of the chamber away from the upper piston (2), and . positioning the lower piston (3) at the upper edge (12) of the brewing chamber, and .Discharging the extracted coffee powder from the lower piston.

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