Coffee brewing device

Abstract

The present invention relates to a fully automatic coffee machine (100), the machine comprising an infusion chamber (1), an upper piston (2) movable within the infusion chamber, and a lower piston (3), the infusion chamber and / or the upper piston being relatively movable between a first closed position configured to compress coffee during infusion and a second closed position configured not to compress, the machine comprising a pressurized hot water fluid system comprising a water supply (101), a water heating device (104), and a water pump (102), the system being connected to a water inlet (13) of a coffee extraction unit, comprising a pressure bypass valve (107), the predetermined threshold pressure of the fluid being delivered being adjustable, the machine comprising a control system configured to move the infusion chamber and / or the upper piston to the first or second closed position, adjusting, in so doing, the predetermined threshold pressure to a first or second predetermined threshold pressure respectively.

Description

Technical Field

[0001] The present invention relates to an apparatus for preparing coffee beverages. Specifically, the present invention relates to a fully automatic coffee apparatus.

Background Art

[0002] A fully automatic coffee machine is configured to automatically prepare coffee. First and foremost, it is configured to prepare pressurized coffee such as espresso, ristretto, lungo, americano, etc.

[0003] Therefore, generally, in a fully automatic coffee machine, a certain amount of roasted and ground (R&G) coffee powder is received, and the coffee of that amount is pressed by at least one movable piston. Pressurized coffee is prepared in an infusion chamber configured to introduce pressurized water through the pressed coffee powder to extract coffee. Finally, the extracted coffee beverage flows out from the outlet of the infusion chamber and into a drinking cup.

[0004] Coffee consumers are demanding an increasing number of types, and they want so-called drip or filter coffee, which is a type of coffee other than pressurized coffee, specifically, long coffee prepared by bringing R&G coffee powder into contact with hot water at low pressure. There is a need for a fully automatic machine that can prepare both pressurized coffee and filter coffee.

[0005] To meet this need, there are various solutions.

[0006] Some fully automatic coffee machines provide external accessories such as a coffee jug (European Patent No. 3669715) or a specific coffee chamber (German Patent Application Publication No. 102018125703). These external accessories are configured to hold R&G coffee powder and allow the hot water sent from the machine to pass through the accessories and the coffee powder. However, the handling of these accessories is cumbersome for the operator. The coffee powder has to be manually filled into the accessories, the accessories have to be manually attached to the water outlet of the machine, and finally, the extracted coffee has to be taken out and the accessories have to be manually cleaned.

[0007] Other fully automatic machines enable the preparation of either pressure - type coffee or filter - type coffee by controlling the movement of a piston within the chamber of the fully automatic machine.

[0008] Publication No. 2002183827 proposes controlling the movement of the piston so that coffee is extracted without pressing the coffee powder when filter - type coffee is selected, while when pressure - type coffee is selected, the piston is controlled to move to press the coffee powder.

[0009] U.S. Patent Application Publication No. 2014150664, International Publication No. 2014119414, and European Patent No. 3253263 disclose similar methods.

[0010] In these prior arts, no interest has been shown in the importance of adjusting the water pressure according to the type of coffee prepared in the infusion chamber. The pressure used for the preparation of filter - type coffee seems to be the result of the size of the chamber set by the position of the piston rather than the selection of a specific water pressure to be introduced into the interior of the chamber.

[0011] As a result, the preparation of filter - type coffee is not optimized.

[0012] As one solution, pressurized hot water can be provided from an adjustable flow pump controlled to provide water at various pressures, such as in European Patent No. 1267685, or two different coffee beverage outlets configured to open at various pressure thresholds can be provided in the overflow chamber, such as in U.S. Patent Application Publication No. 2014 / 150664. However, such embodiments are complex and expensive.

[0013] An object of the present invention is to address the above existing problems.

Summary of the Invention

[0014] In a first aspect of the present invention, there is provided a fully automatic coffee machine comprising a coffee extraction unit and a pressurized hot water fluid system, the machine comprising: The coffee extraction unit comprises: An overflow chamber having an upper rim and a bottom wall for receiving roasted and ground coffee powder; An upper piston, The upper piston is movable through the upper rim of the overflow chamber and is further configured to be movable by relative movement between the overflow chamber and the upper piston inside the overflow chamber; A water inlet; A liquid outlet duct; A lower piston, inside the overflow chamber, The lower piston is movable between a lowest position where the lower piston is located at the bottom of the overflow chamber and A highest position where the lower piston is at the upper rim of the overflow chamber; a lower piston; A used coffee discharge device; and The overflow chamber and / or the upper piston are / is An open position for introducing roasted and ground coffee powder or discharging extracted roasted and ground coffee powder; At least two different first closed positions and second closed positions configured to perform infusion on roasted and ground coffee powder, wherein the first closed position is configured to compress the coffee during infusion, and the second closed position is configured not to compress the coffee during infusion, and is relatively movable between the first closed position and the second closed position, The pressurized hot water fluid system includes at least a water supply section, a water heating device, and a water pump, and is connected to the water inlet of the coffee extraction unit. The fluid supply system includes a pressure bypass valve downstream of the water pump, and the predetermined threshold pressure of the fluid to be delivered can be adjusted by the pressure bypass valve, preferably by an electric actuator. The fully automatic coffee machine includes a control system, and the control system To perform infusion on roasted and ground coffee powder, move the infusion chamber and / or the upper piston to the first closed position or the second closed position. When the infusion chamber and / or the upper piston are respectively in the first closed position or the second closed position, the predetermined threshold pressure of the fluid delivered by the pressure bypass valve is configured to be adjusted to the first predetermined threshold pressure or the second predetermined threshold pressure respectively.

[0015] The coffee extraction unit includes an infusion chamber designed and oriented along a longitudinal axis. This axis can be oriented substantially vertically, or inclined with respect to the vertical direction, or even oriented substantially horizontally.

[0016] The infusion chamber defines an internal volume configured to receive one portion of roasted and ground coffee powder, preferably roasted ground coffee, for which extraction is to be performed. Usually, the chamber has a cylindrical shape with side walls extending from the bottom wall to the upper rim. The longitudinal axis of the cylindrical shape is preferably oriented substantially vertically.

[0017] The top of the infusion chamber is open to allow the introduction of the coffee powder for which extraction is to be performed.

[0018] The extraction unit includes a water inlet configured to introduce water into the chamber to perform extraction on the coffee powder present inside the chamber.

[0019] The coffee machine includes two pistons that can move through the internal volume of the chamber.

[0020] The first piston can move through the upper part of the chamber and is called the upper piston. This upper piston is designed to be able to move through the upper rim of the overflow chamber and further inside the overflow chamber as the overflow chamber and the upper piston move relative to each other. This upper piston is designed to enable the pressing of the coffee powder present inside the chamber, and for this reason, the upper piston is also called the pressing piston.

[0021] The second piston is called the lower piston. The lower piston can move between two end positions inside the overflow chamber. One end position is the lowest position of the second piston inside the chamber. At this lowest position, the head of the lower piston is located on the bottom wall of the overflow chamber. Generally, the lower piston is positioned at this lower position during the operation of introducing coffee powder into the chamber and during the operation of performing extraction on the coffee powder with water.

[0022] The other end position is the highest position of the second piston inside the chamber. At this higher position, the upper surface of the head of the lower piston is at the upper rim of the overflow chamber. Generally, the lower piston is positioned at this higher position during the operation of discharging the extracted coffee powder from the chamber.

[0023] The lower piston includes a head and a rod, and for this reason, the lower piston is also called the pressing piston.

[0024] The lower piston includes a head and a rod.

[0025] The lower piston is assembled in the overflow chamber such that its piston rod extends through the opening in the bottom wall of the overflow chamber and the bottom free end of the rod is positioned outside the chamber. The piston rod is configured to move vertically inside the opening.

[0026] The extraction unit comprises a liquid outlet duct. This duct enables the extracted beverage, preferably coffee, to be poured out of the chamber. Usually, this duct extends from the piston to a nozzle for pouring the beverage into a cup.

[0027] The coffee extraction unit can be configured to perform top - down extraction (gravity extraction) or can be configured to perform bottom - up extraction (anti - gravity extraction).

[0028] In a unit configured for bottom - up extraction, water is introduced through the bottom of the chamber and the extracted coffee is poured out through the top of the chamber. Usually, for a bottom - up configuration, a water inlet is positioned inside the side wall of the chamber, preferably close to the bottom wall, the head of the lower piston has a water opening configured to direct water upward from the water inlet to the coffee powder present inside the chamber, the upper piston comprises a liquid outlet duct.

[0029] In a unit configured for top - down extraction, water is introduced through the top of the chamber and the extracted coffee is poured out through the bottom of the chamber. Usually, for a top - down configuration, a water inlet is positioned inside the upper piston, the head of the upper piston has a water opening configured to direct water downward from the water inlet to the coffee powder present inside the chamber, the lower piston comprises a liquid outlet duct.

[0030] This machine comprises a support frame to which an overflow chamber is attached.

[0031] The relative movement between the overflow chamber and the two pistons can be carried out evenly by keeping the overflow chamber fixed to the support frame and actuating the pistons inside and / or outside the chamber, and / or by actuating the overflow chamber relative to the support frame while the pistons either remain fixed or are driven passively by the movement of the chamber that holds them.

[0032] In a preferred embodiment, the overflow chamber is movable by drive means. The drive means can be a rack or any other known means.

[0033] In this embodiment, preferably, the upper piston is fixed, the rod of the lower piston has a free bottom end positioned outside the overflow chamber and movable with the piston and the chamber, the device comprises a fixed bottom stop wall that can contact the bottom end of the rod of the lower piston, the movement of the lower piston is due to the movement of the overflow chamber and / or contact of the free bottom end with the bottom stop wall or contact of the lower piston with the upper piston.

[0034] Preferably, in this preferred embodiment, the lower piston has no guiding means, holding means, and springs, which means that the lower piston is passive and there are no active means to change the position of the lower piston relative to the overflow chamber.

[0035] Preferably, in this preferred embodiment, the rod and / or the lower piston are provided with friction means for controlling their movement relative to the inner wall of the overflow chamber. These means enable the lower piston to be maintained in one position relative to the overflow chamber.

[0036] In an alternative embodiment, the overflow chamber can be fixedly mounted within the machine, and the upper and lower pistons can be made movable within and out of the overflow chamber by drive means.

[0037] The coffee extraction unit comprises a discharge device for the extracted coffee powder (coffee cake). This discharge device is designed to wipe the area above the upper rim of the chamber by any rotational or translational movement when the lower piston is positioned at its highest position.

[0038] The fully automatic coffee machine comprises a pressurized hot water fluid system comprising at least a water supply section, a water heating device, and a water pump. This system is connected to the water inlet of the coffee extraction unit. Thus, pressurized hot water for performing an overflow on the roasted and ground coffee powder is supplied to the overflow chamber.

[0039] In addition, the fluid supply system comprises a pressure bypass valve. This pressure bypass valve is positioned downstream of the water pump, which means that the outlet of the pump that pumps out the fluid is connected to the inlet of the valve. This pressure bypass valve determines the pressure of the water delivered to the coffee extraction unit. This predetermined threshold pressure of the fluid discharged by the pressure bypass valve is preferably adjustable by an electric actuator.

[0040] Generally, the fully automatic coffee machine comprises a control system, and this control system operates the movement of the overflow chamber and / or the piston, A device of a pressurized hot water fluid system, i.e., is configured to control at least a water heating device, a water pump, and an actuator of a pressure bypass valve.

[0041] As a result, this actuator provides a simple implementation that enables adjustment of the water pressure during coffee extraction, particularly according to the type of coffee preparation (pressurized coffee or filter coffee).

[0042] In addition, the control system moves the overflow chamber and / or the upper piston between an open position for introducing ground roasted coffee or discharging the extracted ground roasted coffee, and at least two different first closed positions and a second closed position configured to perform an overflow on the ground roasted coffee, so as to be relatively movable with respect to each other.

[0043] In the first closed position of the overflow chamber and the upper piston, the coffee is compressed during the overflow, thereby enabling the preparation of pressurized coffee. The overflow chamber and / or the upper piston can be relatively movable to various first closed positions that enable compression of the introduced coffee according to the amount and / or volume of the coffee introduced into the chamber.

[0044] Conversely, in the second closed position of the overflow chamber and the upper piston, the coffee is not compressed during the overflow, thereby enabling the preparation of filter coffee. The coffee powder remains in a state where it does not solidify inside the overflow chamber during the overflow.

[0045] Preferably, this second closed position of the overflow chamber defines the maximum possible closed volume of the overflow chamber.

[0046] Finally, the control system sets a predetermined threshold pressure of the fluid delivered by the pressure bypass valve to a first predetermined threshold pressure when the overflow chamber and / or the upper piston are moved to the first closed position, and When the overflow chamber and / or the upper piston are moved to the second closed position, they are configured to adjust to a second predetermined threshold pressure.

[0047] As a result, the machine enables the optimal preparation of pressure - brewed coffee or filter - brewed coffee since the important parameters of pressure and pressing are met for each type of preparation.

[0048] Preferably, the first predetermined threshold pressure is greater than 4 bar and the second predetermined threshold pressure is less than 4 bar.

[0049] In a preferred embodiment, the coffee extraction unit comprises a coffee outlet valve, which is configured to pour liquid from the liquid outlet duct into either the coffee - pouring area or the waste collector.

[0050] By the operation of this valve, a part of the beverage poured out from the overflow chamber can be sent to the waste collector. This is particularly useful during the preparation of filter - brewed coffee, as the last part of the coffee usually contains a lot of residue and this last part can be diverted from the drinking cup.

[0051] In a particular embodiment, this coffee outlet valve can be actuated by the movement of the overflow chamber.

[0052] Preferably, the machine comprises one single tank for storing coffee beans and one grinder for grinding the stored coffee beans and distributing the ground - roasted coffee into the overflow chamber.

[0053] In fact, the machine enables the preparation of filter - brewed coffee or pressure - brewed coffee from the same ground - roasted coffee powder. There is no need to adjust the particle size of the powder or the type of coffee beans (degree of roasting) according to the type of coffee to be prepared. In fact, adjusting the pressure, and whether to perform compression or not If there is, it is sufficient to provide an optimal preparation from the same roasted and ground coffee powder.

[0054] In a second aspect of the present invention, there is provided a method for preparing a coffee beverage using a fully automatic coffee machine as described above, the method comprising: α obtaining a beverage selection input from a user regarding the type of coffee preparation in the list of at least pressure-brewed coffee and filter-brewed coffee; β based on the beverage selection input of step α, adjusting a predetermined threshold pressure of the bypass pressure valve to a first predetermined threshold pressure for pressure-brewed coffee or a second predetermined threshold pressure for filter-brewed coffee; a supplying a single serving of roasted and ground coffee powder corresponding to the beverage selection input into the overflow chamber at an input position where the upper piston is away from the upper rim of the chamber and outside the chamber, and then 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 pressure-brewed coffee or a second closed position for filter-brewed coffee, and then c introducing hot water through the water inlet, performing extraction on the coffee powder, and pouring out the extracted coffee beverage through the beverage outlet of the upper piston; e discharging the extracted coffee powder from the chamber.

[0055] In a preferred embodiment of the method, when the beverage selection input of step α is filter-brewed coffee, at the end of step c), the method further comprises: d1 actuating the coffee outlet valve to pour liquid from the liquid outlet duct into the waste collector; d2 moving the chamber and the upper piston relative to each other to tamp the extracted coffee powder for a single serving, and repeating this step at least once, preferably at least twice.

[0056] Preferably, in step d2), the chamber (1) and the upper piston (2) are maintained at the tamping position for between 1 second and 3 seconds.

[0057] Alternatively, if the beverage selection input in step α is pressurized coffee, in step b), one portion of coffee powder is pressed by the chamber and the upper piston.

[0058] Generally, in step e), the chamber, the upper piston, and the lower piston are moved relative to each other to position the upper rim of the chamber away from the upper piston and position the lower piston on the upper rim of the overflow chamber, and discharge the extracted coffee powder from the lower piston.

[0059] In the present application, the terms “inner”, “top”, “bottom”, and “side” are used to describe the relative positions of the characteristic parts of the present invention. It should be understood that these terms relate to a device in its normal orientation when positioned within a fully automatic coffee machine for manufacturing beverages, as shown in the drawings.

[0060] The above aspects of the present invention can be combined in any suitable combination. Furthermore, by combining various features in this specification with one or more of the above aspects, combinations other than those specifically illustrated and described can be provided. Further objects and advantageous features of the present invention will become apparent from the “claims”, the “detailed description of the invention”, and the accompanying drawings.

Brief Description of the Drawings

[0061]

Figure 1A

Figure 1B

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3E

Figure 3F

Figure 3G

Figure 3H

Figure 3I

Figure 3J

Figure 3K

Figure 4

Figure 5

Figure 6

Embodiment for Carrying out the Invention

[0062] FIG. 1A is a side view of a fully automatic coffee machine 100 with the side panel removed to show the coffee extraction unit 10 and the coffee powder supply section. FIG. 1B is a perspective view showing the opposite side of this machine 100.

[0063] The coffee extraction unit 10 includes an overflow chamber 1 for receiving one serving of roasted and ground coffee powder. The coffee is stored inside the tank 6 as beans. This tank supplies the coffee beans to the grinder 61 so that one serving of roasted and ground coffee can be distributed from the grinder outlet through the funnel 108 into the interior of the overflow chamber 1.

[0064] Preferably, the overflow chamber 1 is a cylinder having an open top extending from the bottom 11 to the upper rim 12 along the axis XX'. The chamber 1 includes a water inlet conduit (not shown) to which a water fluid line is connected. The water inlet conduit is preferably positioned adjacent to the bottom of the chamber, inside the lower part of the side wall or optionally the bottom wall.

[0065] The coffee extraction unit 10 includes drive means for moving the chamber 1 vertically and diagonally up and down and vice versa. The chamber can be positioned within a carrier 14 configured to slide along a guide shaft. The movement of this carrier can be implemented via a gearbox connecting the carrier to a motor. Any other embodiment can be implemented like a chamber attached to a worm drive actuated by motor means, and the rotation of the worm causes the chamber to translate vertically.

[0066] The coffee extraction unit 10 comprises an upper piston 2. This upper piston 2 has a cylindrical structure and a lower end portion having a diameter substantially equal to the diameter of the chamber, and as the overflow chamber moves upward in the direction of the upper piston, the upper piston can pass through the upper rim 12 of the chamber and further enter the overflow chamber. Thus, the upper piston enables the closing of the overflow chamber during coffee extraction and the pressing of a single portion of roasted and ground coffee powder introduced into the overflow chamber.

[0067] In addition, the upper piston 2 comprises a liquid outlet duct 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 illustrated coffee machine, the liquid outlet duct 21 can be connected either to the coffee dispensing nozzle 9 or to the outlet line 110 to the waste collector by a coffee outlet valve 106. This preferred embodiment provides additional advantages with respect to the quality of the coffee beverage.

[0068] The coffee extraction unit 10 comprises a lower piston 3 shown enlarged in FIG. 2, and this lower piston 3 has a head 32 provided with a water outlet 34 configured to distribute the water introduced through the water inlet conduit during coffee preparation. This head functions as a water distributor.

[0069] 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 is fixed to the bottom of the disc-shaped head 32 and comprises a rod 31 extending downward. The piston 3 is assembled in the chamber with the rod 31 extending below the bottom of the chamber.

[0070] The rod 31 of the lower piston has no guiding means, holding means, or spring, and the lower piston is coaxial with the overflow chamber and movable within the overflow chamber.

[0071] The lower piston 3 is inside the overflow chamber 1 The lowest position (Figure 2) where the lower piston is located on the bottom wall 11 of the overflow chamber, and The lower piston is movable between two end positions, a higher position (Figure 3H) where the lower piston is at the upper rim 12 of the overflow chamber.

[0072] The coffee extraction unit 10 is provided with a discharge device 4 for sweeping out the extracted coffee cake (Figure 3I). The discharge device 4 is positioned slightly above the upper rim of the overflow chamber. The swept-out coffee cake is stored in a waste collector.

[0073] In the illustrated embodiment, the upper piston 2 is fixed. The lower piston 3 is Movable coaxially with the overflow chamber 1, which means that when the chamber 1 moves, the chamber 1 takes the lower piston along with it at the same time, and Movable within the overflow chamber 1, which means that the lower piston can be moved to different positions inside the overflow chamber. The movement of the lower piston 3 inside the overflow chamber is driven by the contact of the head 32 of the lower piston 3 with the upper piston 2 when the overflow chamber moves upward and the connection between the rod 31 of the lower piston 3 and a cam (not shown). In particular, when implementing top-down extraction, any other mechanism according to the state of the art that enables relative movement between the chamber and the upper and lower pistons can also be used.

[0074] This fully automatic coffee machine is provided with a user interface (not shown) that enables the selection of the type of coffee, specifically the selection of the preparation of filter coffee or pressurized coffee.

[0075] The hardware of the user interface may include any suitable device(s), for example, the hardware may include one or more of a joystick button, a knob or a push button, a joystick, an LED, a graphic LDC or a character LDC, a graphics screen having touch-sensitive buttons and / or screen edge buttons.

[0076] Part of the user interface may also be on a mobile app if the fully automatic coffee machine is provided with a communication interface as described below. In that case, at least part of the input and output can be sent to the mobile device through the communication interface.

[0077] This fully automatic coffee machine enables the preparation of pressure-brewed coffee, which is well-known in the state of the art, by performing the following steps: a. Supplying, at the loading position where the upper piston 2 is away from the upper rim 12 of the chamber and outside the chamber, one portion of roasted and ground coffee powder corresponding to the preparation of pressure-brewed coffee into the overflow chamber, and then b. Moving the chamber 1 and the upper piston 2 relative to each other to a first position where the upper opening of the chamber is closed and one portion of the coffee powder is pressed between the lower piston 3 and the upper piston 2. Then c. Introducing hot water into the chamber to extract the coffee powder, and pouring the extracted coffee through the beverage outlet 21 of the upper piston and then through the coffee pouring nozzle 9 inside the cup. Then e. Moving the chamber 1 away from the upper piston 2 so as to move the lower piston upward to the upper rim 12 inside the chamber, thereby discharging the extracted coffee powder from the chamber. At this position, the coffee cake can be wiped off by the discharging device 4 and collected in the waste collector.

[0078] This fully automatic coffee machine enables the preparation of filtered coffee as shown in FIGS. 3A to 3K by performing the following steps: a At the charging position where the upper piston 2 is away from the upper rim 12 of the chamber and outside the chamber (FIG. 3A), a step of supplying a single serving of roasted and ground coffee powder P corresponding to the preparation of filtered coffee into the overflow chamber, and then, b A step of relatively moving the chamber 1 and the upper piston 2 to a second position where the upper opening of the chamber is closed (FIG. 3B). However, the single serving of coffee powder P is not pressed between the lower piston 3 and the upper piston 2. As a result, the coffee powder is kept in an unconsolidated state during beverage preparation, which is an important condition for the preparation of filtered coffee. Preferably, the chamber 1 and the upper piston 2 are positioned relative to each other to provide the largest internal volume while keeping the chamber closed.

[0079] c A step of introducing hot water W into the chamber (FIG. 3C), which has the effect of extracting the coffee powder. When the water fills the chamber volume, the extracted coffee filter is poured into the cup through the beverage outlet 21 of the upper piston and then through the coffee spout nozzle 9 (FIG. 3D).

[0080] When the introduction of water is completed (FIG. 3E), since the coffee powder was not pressed during extraction, a certain amount of liquid remains inside the chamber. This extracted coffee and the remaining liquid form a kind of sludge. The chamber needs to be thoroughly cleaned before preparing new coffee. Then, at least the following steps are performed.

[0081] Step of moving the d2 chamber 1 and the upper piston 2 relative to each other to tamp the coffee powder present in the chamber. During this 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 released by the tamping operation could be poured inside the drinking cup through the coffee nozzle 9 and form part of a filtered coffee beverage. In that case, the final beverage may contain some small solid residues that are within the acceptable range for this type of coffee.

[0082] The position of the chamber for obtaining the tamping effect can be determined by measuring the current supplied to the motor that operates the chamber and stopping the movement of the chamber when a preset current threshold is reached. Any alternative known method for detecting the tamping position can also be used.

[0083] Preferably, this tamping is repeated at least once, preferably at least twice, by moving the chamber 1 away from the upper piston 2 and then moving them relative to each other to tamp the coffee powder. In this second tamping operation, the chamber can be moved, for example, 10 mm or 20 mm away from the upper piston, and it is not necessary to move the chamber to its widest internal volume. This operation enables the introduction of air into the water inlet conduit and the discharge of the retained water - coffee liquid residues, as a result of which the operations of drying the ground coffee and compressing the coffee cake are improved.

[0084] The coffee powder can be completely dried by several tamping operations. By improving the drying, it is ensured that there are fewer residues remaining in the chamber, the cleaning of the chamber is better, and the wiping of the coffee cake 7 by the discharge device 4 is better.

[0085] Depending on the type of coffee powder used, the coffee powder may exhibit various hygroscopic properties, which directly affect the ease of drying the wet powder. This property may depend on the degree of roasting, the nature of the coffee beans (Arabica, Robusta, etc.), and the grinding degree. Therefore, the number of tamping operations can be adjusted according to the coffee powder used.

[0086] Moving the e-chamber 1 away from the upper piston 2 to move the lower piston upward to the upper rim 12 inside the chamber to discharge the extracted coffee powder from the chamber. At this position, the coffee cake can be wiped off by the discharge device 4 and collected in the waste collector 8 (Figs. 3G - 3K).

[0087] In a preferred embodiment, the fully automatic coffee machine is provided with the coffee outlet valve 106 described in FIGS. 1A and 1B. To clean the chamber, the following steps are performed at the end of the introduction of water and the extraction of coffee (step c): d1 Actuating the coffee outlet valve 106 so that liquid can be sent from the liquid outlet duct 21 to the waste collector 8, and d2 Moving the chamber 1 and the upper piston 2 relative to each other to tamp the coffee powder present in the chamber. During this 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 shown in Fig. 3F. As a result, the liquid with a large amount of coffee residue poured out is not poured into the final coffee filter beverage. Here too, preferably, this tamping is repeated at least once, preferably at least twice, by moving the chamber 1 away from the upper piston 2 and then moving them relative to each other to tamp the coffee powder, to improve the cleaning of the chamber.

[0088] This coffee outlet valve 6 can also be used to preheat the chamber 1 with hot water before preparing the coffee. Hot water can be introduced into the interior of the chamber for a sufficient time to heat the walls of the chamber, and then this water can be sent into the waste collector by the coffee outlet valve 6. Then, coffee preparation can be started.

[0089] The fully automatic coffee machine comprises a water fluid system as schematically shown in FIG. 4.

[0090] The lines of this system are at least continuously a water tank 101, a pump 102, and a heater 104.

[0091] The end of this hot water fluid line is connected to the water inlet 13 of the overflow chamber portion of the coffee extraction unit 10.

[0092] Preferably, the fluid system can comprise a flow meter 103 for better control of the preparation.

[0093] Preferably, the fluid system can comprise a valve 105 that enables the pumped water to be dispensed at another supply point, specifically in the dispensing area of the coffee beverage for the preparation of Americano coffee. In such a preparation, the hot water sent from the overflow chamber is added directly inside the coffee cup.

[0094] In a particular embodiment, the fluid line can comprise a bypass line (shown in dotted lines) around the heater 104 so that water can be used for cold preparation. In that case, something like cold brew coffee can be obtained.

[0095] In addition, the system includes a pressure bypass valve 107 downstream of the water pump 102. This pressure bypass valve includes two check valves, and the valve is configured such that a predetermined threshold pressure of the fluid delivered by the pressure bypass valve can be adjusted, preferably by an electric actuator, for example by a gearbox 1075 connected to the motor M.

[0096] FIG. 6 schematically shows such a pressure bypass valve 107. This valve 107 includes a first check valve 1073a positioned between an inlet line 1071 for the pumped water and an outlet line 1077 for the water delivered to the heater. The valve 107 includes a second check valve 1073b configured to adjust the maximum allowable pressure within the outlet line 1077.

[0097] The adjustment of this maximum allowable pressure is performed by controlling the tension of the spring of the second check valve 1073b. This tension is adjusted by an adjustable screw 1074. The valve 107 includes a motor M and a gearbox 1075 to control the movement of the adjustable screw 1074 and accordingly control the water pressure control in the outlet line 1077. An absolute position sensor 1076 can be provided to control the position of the screw. The valve 107 includes a bypass line 1072 for diverting a portion of the water from the outlet line 1077 as needed in response to a predetermined threshold pressure that has been adjusted. Preferably, this bypass line 1072 is connected to an upstream portion of the pump within the fluid system.

[0098] As a result, the fluid supply system enables an easy and rapid adjustment of the water pressure introduced into the extraction unit. This pressure can be adjusted each time coffee is prepared and may vary particularly depending on the preparation of pressurized coffee or filter coffee.

[0099] In the simplest embodiment, the motor M is configured to adjust the screw 1074 between two positions, namely a first position corresponding to a pressure for the preparation of pressurized coffee, typically exceeding 4 bar, preferably exceeding 7 bar, and a second position corresponding to a pressure for the preparation of filtered coffee, typically less than 4 bar.

[0100] Figure 5 is a schematic diagram of a control system of a fully automatic coffee machine with the fluid system of Figure 4.

[0101] The control system typically comprises a processing unit 111, a power supply 1111, and a memory unit 1112.

[0102] The processing unit 111 generally comprises a memory and input / output system components typically configured as an integrated circuit such as a microprocessor or a microcontroller. The power supply 1111 is operable to supply electrical energy to the controlled components and the processing unit.

[0103] The processing unit 111 generally comprises a memory unit 1112 for storing instructions as program code and optionally data.

[0104] The instructions stored in the memory unit 112 can be idealized to include a program for adjusting the internal volume of chamber 1 and a predetermined threshold pressure of the fluid delivered by the pressure bypass valve according to the type of coffee to be prepared based on the input provided by the user interface 109.

[0105] During coffee beverage preparation, the control system obtains a beverage selection input from the user regarding the type of coffee preparation in the list of pressurized coffee and filtered coffee, Actuate the drive means of the chamber to move the overflow chamber and / or the upper piston to a first closed position for pressure-type coffee input or to a second position for filter-type coffee preparation. The motor M of the pressure bypass valve is operable to actuate and adjust a predetermined threshold pressure of the fluid delivered by the pressure bypass valve to a first predetermined threshold pressure for pressure-type coffee input and to a second predetermined threshold pressure for filter-type coffee.

[0106] Although the present invention has been described using a fully automatic coffee machine having an extraction unit based on bottom-up extraction, the same preparation method is applicable to an extraction unit based on top-down extraction.

[0107] Although the present invention has been described with reference to the embodiments illustrated above, it will be understood that the claimed invention is in no way limited to these illustrated embodiments.

[0108] Modifications and variations can be effected without departing from the scope of the invention as defined in the claims. Further, where known equivalents exist for specific features, such equivalents are incorporated as if specifically recited herein.

[0109] As used herein, the terms "comprising", "having", and the like are not to be construed in an exclusive or exhaustive sense. In other words, they are intended to mean "including but not limited to".

Explanation of Signs

[0110] 10 Coffee extraction unit 1 Overflow chamber 11 Bottom 12 Upper rim 13 Water inlet 14 Carrier 2 Upper piston 21 Outlet duct 3 Lower piston 31 Piston rod 32 Head 33 Water inlet 34 Water outlet 4 Discharge device 5 Outlet pipe 6 Coffee bean tank 61 Grinder 7 Coffee cake 8 Waste collector 9 Pouring nozzle 100 Coffee machine 101 Water tank 102 Pump 103 Flow meter 104 Heater 105 Valve 1051 Americano water line 106 Coffee outlet valve 107 Pressure bypass valve 1071 Inlet line 1072 Bypass line 1073a, 1073b Check valve 1074 Adjustable screw 1075 Gear box 1076 Position sensor 1077 Outlet line 108 Ground coffee funnel 109 User interface 110 Outlet line to waste collector 111 Processing unit 1111 Power supply 1112 Memory unit W Water P Roasted and ground coffee powder C Coffee beverage R Residue M Motor

Claims

1. An automatic coffee machine (100) comprising a coffee extraction unit (10) and a pressurized hot water fluid system, wherein the coffee extraction unit (10) comprises, an overflow chamber (1) having an upper rim (12) and a bottom wall (11) for receiving roasted and ground coffee powder, an upper piston (2) configured to be movable through the upper rim of the overflow chamber and further movable by relative movement between the overflow chamber and the upper piston inside the overflow chamber, a water inlet (13), a liquid outlet duct (21), a lower piston (3) inside the overflow chamber (1), a lowest position where the lower piston is located at the bottom (11) of the overflow chamber, a lower piston (3) movable between a highest position where the lower piston is at the upper rim (12) of the overflow chamber, and a discharge device (4) for used coffee, wherein the overflow chamber and / or the upper piston are relatively movable between, an open position for introducing roasted and ground coffee powder or discharging extracted roasted and ground coffee powder, at least two different first closed positions and second closed positions configured to perform overflow on the roasted and ground coffee powder, the first closed position being configured to compress coffee during overflow, and the second closed position being configured not to compress coffee during overflow, the pressurized hot water fluid system comprising at least a water supply unit (101), a water pump (102), and preferably a water heating device (104), connected to the water inlet (13) of the coffee extraction unit, the fluid supply system comprising a pressure bypass valve (107) downstream of the water pump, and a predetermined threshold pressure of the fluid delivered by the pressure bypass valve being adjustable preferably by an electric actuator (1071), the automatic coffee machine comprising a control system, the control system being configured to, move the overflow chamber and / or the upper piston to the first closed position or the second closed position to perform overflow on the roasted and ground coffee powder, When the overflow chamber and / or the upper piston are each in the first closed position or the second closed position, the predetermined threshold pressure of the fluid delivered by the pressure bypass valve is configured to be adjusted to a first predetermined threshold pressure or a second predetermined threshold pressure, respectively. Fully automatic coffee machine (100). **Claim 2** The fully automatic coffee machine (100) according to claim 1, wherein the second closed position of the overflow chamber defines the maximum possible closed volume of the overflow chamber. **Claim 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. **Claim 4** The overflow chamber comprises the water inlet (13). The upper piston (2) comprises the coffee outlet duct (21). The fully automatic coffee machine (100) according to any one of claims 1 to 3. **Claim 5** The coffee extraction unit comprises a coffee outlet valve (6), and the coffee outlet valve (6) is configured to pour liquid from the liquid outlet duct into either a coffee pouring area or a waste collector. The fully automatic coffee machine (100) according to any one of claims 1 to 4. **Claim 6** The fully automatic coffee machine (100) according to claim 5, wherein the coffee outlet valve (106) is actuated by the movement of the overflow chamber. **Claim 7** The machine comprises one tank (6) for storing coffee beans and one grinder (61) for grinding the stored coffee beans, roasting them and distributing the ground coffee into the overflow chamber (1). The fully automatic coffee machine (100) according to any one of claims 1 to 6. **Claim 8** A method for preparing a coffee beverage using the fully automatic coffee machine according to any one of claims 1 to 6, comprising: α obtaining a beverage selection input from a user regarding the type of coffee preparation in the list of at least pressurized coffee and filtered coffee; β based on the beverage selection input of step α, adjusting the predetermined threshold pressure of the bypass pressure valve to the first predetermined threshold pressure for pressurized coffee or the second predetermined threshold pressure for filtered coffee; a) At the charging position where the upper piston (2) is outside the chamber away from the upper rim (12) of the chamber, supplying one charge of roasted and ground coffee powder corresponding to the beverage selection input into the infusion chamber; and then, b) Based on the beverage selection input of step α, moving the chamber (1) and the upper piston (2) relative to each other to the first closed position for pressure - type coffee or the second closed position for filter - type coffee; and then, c) Introducing hot water through the water inlet (3), extracting the coffee powder, and pouring out the extracted coffee beverage through the beverage outlet (21) of the upper piston; e) Discharging the extracted coffee powder from the chamber, a method comprising the above steps.

9. When the beverage selection input of step α is filter - type coffee, at the end of step c): d1) Actuating the coffee outlet valve (106) to pour liquid from the liquid outlet duct into the waste collector (8); d2) Moving the chamber (1) and the upper piston (2) relative to each other to tamp the one - charge of extracted coffee powder, and repeating this step at least once, preferably at least twice; The method according to claim 8, comprising the above steps.

10. The method according to claim 9, wherein in step d2), the chamber (1) and the upper piston (2) are maintained at the tamping position for between 1 second and 3 seconds.

11. When the beverage selection input of step α is pressure - type coffee, in step b), the one - charge of coffee powder is pressed between the lower piston (3) and the upper piston (2) within the chamber (1), the method according to any one of claims 7 - 10.

12. In step e), the chamber (1), the upper piston (2), and the lower piston (3) are moved relative to each other to position the upper rim (12) of the chamber away from the upper piston (2), and to position the lower piston (3) at the upper rim (12) of the infusion chamber, discharging the extracted coffee powder from the lower piston, The method according to any one of claims 7 - 11.

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