Coffee maker provided with means for pre-infusion of the cake of coffee powder

Abstract

The present invention relates to a coffee machine comprising one or more brewing groups and having a system for delivering water at reduced pressure at the pre-infusion step of the cake of coffee powder before the actual infusion and brewing step of a coffee-based beverage. According to the invention, for each brewing group (3a, 3b) of the coffee machine (1), an auxiliary feed duct (9a, 9b) in which water flows at a higher pressure and an auxiliary bypass duct (11a, 11b) in which water flows at a reduced pressure can be selectively communicated with the respective brewing group. The pre-infusion system of the coffee machine (1) allows to implement the pre-infusion in each brewing group in a separate and independent manner.

Description

Technical Field

[0001] This invention relates to coffee machines comprising one or more brewing units, and more particularly to espresso machines.

[0002] In particular, the present invention relates to a coffee machine equipped with a system for delivering water under reduced pressure at a pre-infusion step of coffee grounds, the purpose of which is to “wet” the coffee grounds before the actual infusion step of delivering water under high pressure.

[0003] Advantageously, the coffee machine according to the invention also allows for a post-infusion step by re-supplying water under reduced pressure after the actual infusion step. Background Technology

[0004] Coffee machines, especially espresso machines, are known in which water under high pressure and high temperature flows through a coffee puck made of coffee powder in order to produce a coffee-based beverage.

[0005] Typically, the espresso machine includes one or more brewing units and a filter holder unit containing a filter associated with each brewing unit in the brewing units: a predetermined dose of coffee grounds obtained by grinding coffee beans is introduced into the filter holder and then tamped by means of a tamping rod, thereby obtaining a coffee puff made from the coffee grounds.

[0006] The espresso machine includes or is connected to a water source that is at low pressure and low temperature, and the espresso machine is equipped with one or more water heaters for raising the temperature of the water and one or more pumps for raising the pressure of the water, such that the high-pressure and high-temperature water flow can be delivered to the brewing unit of the coffee machine (or to a brewing unit within the brewing unit) and through the coffee puck.

[0007] The coffee machine also includes a control unit that allows adjustment of operating parameters for the water heater, pump, and hydraulic circuit connecting the water source to the brewing unit, whereby water pressure, temperature, and flow rate values ​​can be set each time according to the desired sensory characteristics of the prepared beverage. In particularly complex solutions, it is also conceivable that one or more of the pressure, temperature, and flow rate of the water reaching the brewing unit are not constant throughout the brewing time, but vary according to predetermined conditions stored in the control unit.

[0008] In any case, coffee-based beverages are brewed using water at high temperatures (e.g., about 93°C) and high pressures (e.g., about 9 bar).

[0009] However, it has been found that introducing high-pressure water directly through the coffee puck has some drawbacks that may negatively affect the quality of the resulting beverage.

[0010] In particular, it has been observed that high-pressure water flow in contact with a coffee puck made of tampd and dried coffee powder tends to establish and follow a preferred path, thereby preventing the uniform extraction of aromatic compounds from the entire dose of coffee powder. In other words, extraction along the preferred path occurs only during the first part of the brewing process, while during the second part of the brewing process, the water flow cannot further extract aromatic compounds; alternatively, in those areas of the coffee puck away from the preferred path, the extraction of aromatic compounds at the end of the brewing process is only localized and non-optimal.

[0011] To overcome the aforementioned drawbacks, known solutions envision providing a pre-infusion step upstream of the actual infusion step, in which the coffee puck is passed through by a stream of water at a high temperature but low pressure.

[0012] This low-pressure water flow allows the coffee puck to be evenly "wetted" without initiating the process of extracting aromatic substances from the coffee grounds.

[0013] When coffee grounds are "wetted" in this way and then passed through by a stream of water under high pressure, the water is observed to diffuse evenly within the coffee grounds, and thus the even and optimized extraction of aromatic compounds from the coffee grounds is observed.

[0014] A further effect of using low-pressure water for the pre-soaking step is to release gases that may be present in the coffee grounds (especially carbon dioxide that may form inside the coffee beans during roasting).

[0015] The release of gas from the coffee puck has the beneficial effect of increasing the contact surface between water and coffee powder particles, thus increasing the efficiency of extracting aromatic substances from the coffee powder.

[0016] To achieve the process described above—which includes both the pre-soaking step and the actual soaking step—different technical solutions have been implemented in the past.

[0017] However, a common fact among the known solutions is that they are all very complex.

[0018] As an example, patent application EP 2 642 903 in the applicant's name describes a coffee machine including a brewing unit, to which water at different pressure levels can be delivered. For this purpose, the coffee machine includes a hydraulic circuit with a first and a second conduit arranged parallel to each other, and a pump arranged to increase water pressure on one (and only one) of the conduits.

[0019] In the solutions described in the cited literature above, dedicated valves are provided in both the first and second pipelines, and these valves are not simple shut-off valves, but are designed to dynamically control the pressure in each pipeline.

[0020] In this solution, as well as other known solutions, this complexity typically leads to increased production costs, increased space required for hydraulic circuits, and an increased risk of failure—due to the presence of numerous and / or complex components.

[0021] The aforementioned drawbacks are even more relevant in the case of professional espresso machines, which typically include multiple brewing units (often used in cafes, restaurants, hotels, etc.).

[0022] In this case, each brewing unit must have a dedicated pre-infusion system, which increases the complexity of the entire coffee machine and the associated drawbacks.

[0023] Alternatively, if a pre-infusion system that is shared across all brewing sets is provided, the brewing cycle of another brewing set cannot be started once one brewing set has been used.

[0024] The object of the present invention is to overcome the problems of the prior art by providing a coffee machine with a simple and reliable system for pre-infusing coffee powder with a reduced number of components.

[0025] Another object of the present invention is to provide a coffee machine that can be equipped with a separate subsystem for pre-infusing coffee pucks for each brewing unit of the coffee machine, without involving any excessive increase in the overall complexity of the coffee machine's structure itself.

[0026] These and other objectives are achieved by a coffee machine as claimed in the appended claims. Summary of the Invention

[0027] In its own way, the coffee machine according to the invention includes one or more brewing units, a water source at low pressure and low temperature, a hydraulic circuit connecting the water source to the one or more brewing units, a pump, and a water heater. The pump is arranged in the hydraulic circuit and located between the water source and the one or more brewing units and is adapted to increase the pressure of the water circulating in the hydraulic circuit. The water heater is arranged in the hydraulic circuit and located between the water source and the one or more brewing units and is adapted to increase the temperature of the water circulating in the hydraulic circuit such that water at high temperature and high pressure can pass through the one or more brewing units.

[0028] Each of one or more brewing units in a coffee machine is adapted to receive a filter holder containing a puck made of tamped coffee powder, through which a flow of water at high temperature and high pressure passes in order to obtain a brewed coffee-based beverage.

[0029] The coffee machine according to the invention is provided with a system for pre-soaking the coffee powder.

[0030] Correspondingly, the hydraulic circuit includes a supply pipe connected to a water source and a bypass pipe branching off from the supply pipe upstream of the pump.

[0031] Downstream of the pump, the feed line branches into one or more auxiliary feed lines, one of which serves each brewing unit of the coffee machine. Similarly, the bypass line branches into one or more auxiliary bypass lines, one of which serves each brewing unit of the coffee machine.

[0032] For each brewing unit, the pre-infusion system of the coffee machine according to the invention includes a valve assembly that receives a corresponding auxiliary feed pipe and a corresponding auxiliary bypass pipe at its inlet and selectively connects the auxiliary feed pipe or the auxiliary bypass pipe to an outlet pipe that delivers water to the corresponding brewing unit.

[0033] Depending on whether the valve assembly connects the auxiliary feed line or auxiliary bypass line to the corresponding outlet line, water flow at a pressure determined by the pump (high pressure) or at a pressure equal to the pressure present in the hydraulic circuit upstream of the pump (low pressure) will be sent to the corresponding brewing unit.

[0034] In the simplest embodiment of the invention, the valve assembly includes a single three-way valve, such as a three-way electronic valve.

[0035] Therefore, it is evident that the coffee machine according to the invention includes a system for pre-infusing coffee powder, which is very simple and comprises a limited number of components: in particular, the system does not involve the need for a separate pump for each brewing unit and can provide a single valve for each brewing unit.

[0036] Meanwhile, the coffee machine according to the invention includes a system for pre-infusing coffee powder, which allows several brewing groups to operate simultaneously and independently of each other: an auxiliary feed pipe, a corresponding auxiliary bypass pipe, and a valve assembly into which the pipes converge form a pre-infusing subsystem for the respective brewing group, the operation of which is completely independent of the operation of the pre-infusing subsystems of the other brewing groups.

[0037] Advantageously, the pre-infusion system of the coffee machine according to the invention, in addition to effectively allowing the coffee puck to be evenly "wetted" with high-pressure water before the actual infusion step, can also be used to implement a post-infusion step after the actual infusion step. In the post-infusion step, the valve assembly reconnects the auxiliary bypass pipe to the corresponding outlet pipe, thereby sending a low-pressure water flow to the corresponding brewing unit. Attached Figure Description

[0038] According to the appendix Figure 1 The features and advantages of the invention will become more apparent from the description of preferred embodiments given by the non-limiting examples.

[0039] Figure 1 The hydraulic circuit of the coffee machine according to the present invention is schematically shown. Detailed Implementation

[0040] Reference Figure 1 The illustration shows the hydraulic circuit of a coffee machine according to the present invention. The coffee machine may be, for example, a so-called "semi-automatic" type espresso machine.

[0041] In its own way, the coffee machine 1 according to the invention includes a water source (not shown), one or more brewing units, particularly two brewing units 3a, 3b in the illustrated embodiment, and a hydraulic circuit connecting the water source to the brewing units.

[0042] The water source may include, for example, a reservoir integrated into or connected to a coffee machine, or a connecting element for connecting to an external water pipe.

[0043] A pump 5, designed to increase the pressure of the water circulating in the hydraulic circuit, and a water heater 7, designed to increase the temperature of the water circulating in the hydraulic circuit, are arranged in the hydraulic circuit, so that water flowing under high pressure and high temperature can pass through each brewing group 3a, 3b.

[0044] Each brewing unit 3a, 3b receives a filter holder containing a predetermined dose of compressed coffee powder (coffee puck), thereby allowing the infusion and brewing of a coffee-based beverage to be achieved by means of a high-pressure and high-temperature water flow passing through the coffee puck.

[0045] For the reasons described above, it is preferable to have a pre-infusion step before the actual infusion step, during which the coffee puff present in the filter holder inserted into the brewing assembly is passed through by a flow of water under low pressure.

[0046] For this purpose, the hydraulic circuit of the coffee machine 1 according to the invention includes a supply pipe 9 connected to a water source and a bypass pipe 11 branching off from the supply pipe upstream of the pump 5.

[0047] Downstream of pump 5, the feed pipe 9 branches into two auxiliary feed pipes or soaking pipes 9a and 9b, one of which is used for each brewing group 3a and 3b.

[0048] The bypass pipe 11 branches into two auxiliary bypass pipes or pre-soaking pipes 11a and 11b.

[0049] The first auxiliary feed pipe 9a and the first auxiliary bypass pipe 11a converge toward the first valve assembly; in particular, in the illustrated embodiment, the first auxiliary feed pipe 9a and the first auxiliary bypass pipe 11a are connected to the corresponding inlets of the first three-way electronic valve 13a.

[0050] Similarly, the second auxiliary feed pipe 9b and the second auxiliary bypass pipe 11b converge toward the second valve assembly, and more specifically, the second auxiliary feed pipe 9b and the second auxiliary bypass pipe 11b are connected to the respective inlets of the second three-way electronic valve 13b.

[0051] The outlets of each three-way electronic valve 13a, 13b are connected to the corresponding outlet pipes 15a, 15b.

[0052] like Figure 1 As shown, flow meters 17a and 17b can be installed on each outlet pipe 15a and 15b.

[0053] Each outlet pipe 15a, 15b passes through the water heater 7 and the temperature of the water flowing in the outlet pipes rises. For this purpose, each outlet pipe may be provided with a heat exchanger 19a, 19b at its portion arranged within the water heater 7.

[0054] Downstream of the water heater 7, each outlet pipe 15a, 15b leads to the corresponding brewing unit 3a, 3b. Each brewing unit 3a, 3b is equipped with its own brewing unit valve 21a, 21b, which is arranged on the corresponding outlet pipe 15a, 15b to selectively allow or prevent water from entering the brewing unit itself.

[0055] It will be apparent to those skilled in the art that each three-way electronic valve 13a, 13b may alternatively connect the corresponding auxiliary feed pipe 9a, 9b or the corresponding auxiliary bypass pipe 11a, 11b to the corresponding outlet pipe 15a, 15b and thus to the corresponding brewing unit 3a, 3b.

[0056] Therefore, if the three-way valves 13a and 13b connect the auxiliary bypass pipes 11a and 11b to the outlet pipes 15a and 15b, and thus to the corresponding brewing units 3a and 3b, then water at high temperature but low pressure (the pressure present in the hydraulic circuit upstream of pump 5) will be delivered to the brewing units. In this way, the coffee puck can be pre-infused.

[0057] Alternatively, if the three-way electronic valves 13a, 13b connect the auxiliary feed pipes 9a, 9b to the outlet pipes 15a, 15b and thus to the corresponding brewing units 3a, 3b, then water at high temperature and high pressure (the pressure determined by the operating conditions of pump 5) will be supplied to the brewing units. In this way, the coffee grounds can be actually steeped, while simultaneously extracting aromatic substances and brewing a coffee-based beverage.

[0058] It should be noted that a pressure reducer may be arranged in the bypass pipe 11 or in one or more of the auxiliary bypass pipes 11a, 11b (possibly in all auxiliary bypass pipes 11a, 11b) so that a desired pressure value can be set for the pre-soaking step of all brewing groups or for the pre-soaking step of each brewing group in the brewing group.

[0059] Similarly, pressure regulators may be arranged in the feed pipe 9 or in one or more of the auxiliary feed pipes 9a, 9b (possibly in all auxiliary feed pipes 9a, 9b) so that a desired pressure value (different from the pressure value determined by the pump 5) can be set for the soaking step of all brewing groups or for the soaking step of each brewing group in the brewing group.

[0060] As is clear from the above description, in terms of its simplicity, the pre-infusion system of the coffee machine according to the invention allows coffee grounds to be supplied with a water flow having a first, lower pressure value or a second, higher pressure value.

[0061] Introducing the pre-infusion system into a coffee machine does not involve introducing an additional pump or water heater; the only additional component related to the pre-infusion system is the three-way electronic valve for each brewing unit. Therefore, even in coffee machines with a large number of brewing units, the increase in the complexity of the hydraulic circuit structure (and thus its production cost) is limited in any case.

[0062] Advantageously, the first auxiliary feed pipe 9a, the first auxiliary bypass pipe 11a, and the first electronic valve 13a form a pre-soaking subsystem for the first brewing group 3a. This pre-soaking subsystem is separate from and independent of the pre-soaking subsystem for the second brewing group 3b, which includes the second auxiliary feed pipe 9b, the second auxiliary bypass pipe 11b, and the second electronic valve 13b. Therefore, each brewing group will be able to operate independently of the other brewing groups.

[0063] In other words, by acting on the three-way electronic valves 13a and 13b, it is possible to deliver low-pressure water to one brewing group while simultaneously delivering high-pressure water to another brewing group.

[0064] The operation of the coffee machine according to the present invention can be summarized as follows:

[0065] - When pump 5 and water heater 7 are turned on, the brewing cycle of brewing unit 3a of coffee machine 1 is triggered;

[0066] - A filter holder containing a coffee pouch made of pressed coffee powder is inserted into the brewing assembly 3a;

[0067] - The corresponding electronic valve 13a is switched to the position where electronic valve 13a connects auxiliary bypass pipe 11a with outlet pipe 15a, and the corresponding brewing group valve 21a is switched to the position where brewing group valve 21a allows outlet pipe 15a to connect with brewing group 3a; in this way, the brewing group is supplied with water at high temperature and low pressure (pre-soaking) and the coffee puck is "wetted".

[0068] - After a predetermined time interval, the electronic valve 13a switches to a position where the electronic valve 13a connects the auxiliary feed pipe 9a to the outlet pipe 15a; in this way, the brewing unit is supplied with water under high temperature and high pressure (immersion) and brews coffee-based beverages.

[0069] - After another predetermined time interval, the brewing unit electronic valve 21a is switched to the position where the outlet pipe 15a is prevented from communicating with the brewing unit 3a and the brewing of the coffee-based beverage ends.

[0070] It will be apparent to those skilled in the art that the coffee machine 1 will be equipped with or connected to a control unit having a memory containing all the parameters necessary for preparing different coffee-based beverages that can be selected in the coffee machine, and the memory of the control unit will, among other things, contain values ​​for the time interval for the pre-infusion step and values ​​for the time interval for the infusion step for each beverage.

[0071] In some applications, and for some types of coffee-based beverages, it may be advantageous to finish preparation by feeding water under low pressure to the coffee puck.

[0072] Advantageously, this post-infusion step can be achieved under low pressure in the coffee machine according to the invention.

[0073] In fact, it would be sufficient for the electronic valve 13a to be switched back to the position where the electronic valve 13a connects the auxiliary bypass pipe 11a to the outlet pipe 15a, while keeping the brewing group valve 21a in the position where the outlet pipe 15a connects to the brewing group 3a, so that the brewing group can be supplied with water at high temperature and low pressure again.

[0074] This post-infusion step will also have a predetermined duration (for each beverage) stored in the memory of the coffee machine's control unit.

[0075] Obviously, the embodiments described above in relation to the accompanying drawings have been provided by way of example only and without any limiting meaning, and various modifications and variations can be made therefrom within the scope of protection that are attainable by those skilled in the art without departing from the scope of protection as defined in the appended claims.

[0076] In particular, while the use of three-way electronic valves is particularly advantageous in simplifying hydraulic circuits and reducing the total number of components used, it is clear that the valve assembly of a pre-soaking system may have any other configuration suitable for selectively connecting its own outlet line to a corresponding auxiliary feed line or a corresponding auxiliary bypass line, and may include combinations of several valves arranged in series and / or in parallel.

Claims

1. A coffee machine (1) comprising a water source, one or more brewing units (3a, 3b), and a hydraulic circuit connecting the water source to the one or more brewing units, wherein, In the hydraulic circuit, between the water source and the one or more brewing units, there is a pump (5) designed to increase the pressure of the water circulating in the hydraulic circuit and a kettle (7) designed to increase the temperature of the water circulating in the hydraulic circuit, wherein each brewing unit is arranged to receive a filter holder containing coffee grounds, wherein the hydraulic circuit includes a supply pipe (9) connected to the water source and a bypass pipe (11) branching from the supply pipe upstream of the pump (5), wherein the supply pipe (9) branches downstream of the pump (5) into one or more auxiliary supply pipes (9a, 9b), one An auxiliary feed pipe is used for each brewing group of the coffee machine, and the bypass pipe (11) branches into one or more auxiliary bypass pipes (11a, 11b), one auxiliary bypass pipe being used for each brewing group of the coffee machine, and wherein each auxiliary feed pipe (9a, 9b) and each auxiliary bypass pipe (11a, 11b) is connected to the inlet of a valve assembly (13a, 13b) that selectively connects the auxiliary feed pipe (9a, 9b) or the auxiliary bypass pipe (11a, 11b) to a corresponding outlet pipe (15a, 15b) connected to the respective brewing group (3a, 3b). The valve assembly (13a, 13b) is characterized in that it is switched to a position connecting the auxiliary bypass pipe (11a, 11b) with the corresponding outlet pipe (15a, 15b) for a predetermined time interval, and after the predetermined time interval, the valve assembly (13a, 13b) is switched to a position connecting the auxiliary feed pipe (9a, 9b) with the corresponding outlet pipe (15a, 15b) for another predetermined time interval. The coffee machine is equipped with or connected to a control unit having a memory, the memory of which contains a value for the predetermined time interval and another value for the other predetermined time interval.

2. The coffee machine (1) according to claim 1, comprising two or more brewing units.

3. The coffee machine (1) according to claim 1 or 2, wherein, Each valve assembly (13a, 13b) includes a three-way electronic valve (13a, 13b).

4. The coffee machine (1) according to claim 1 or 2, wherein, The water heater is arranged in the hydraulic circuit downstream of the valve assembly (13a, 13b).

5. The coffee machine (1) according to claim 4, wherein, The outlet pipes (15a, 15b) pass through the water heater (7) and a corresponding heat exchanger (19a, 19b) is provided at the water heater.

6. The coffee machine (1) according to claim 1 or 2, wherein, A brewing group valve (21a, 21b) is provided on each outlet pipe (15a, 15b), which selectively allows or prevents the connection of the corresponding outlet pipe to the corresponding brewing group (3a, 3b).

7. The coffee machine (1) according to claim 2, wherein, Each auxiliary feed pipe (9a, 9b), together with the corresponding auxiliary bypass pipe (11a, 11b) and the corresponding valve assembly (13a, 13b), forms a pre-soaking subsystem for the corresponding brewing group (3a, 3b). This pre-soaking subsystem can be driven and controlled separately from and independently of the pre-soaking subsystems of the other brewing groups (3b, 3a).

8. The coffee machine (1) according to claim 1 or 2, wherein, A pressure reducer is provided in the bypass pipe (11) or in one or more of the auxiliary bypass pipes (11a, 11b).

9. The coffee machine (1) according to claim 1 or 2, wherein, A pressure reducer is provided in the feed pipe (9) or in one or more of the auxiliary feed pipes (9a, 9b).

10. The coffee machine (1) according to claim 1 or 2, wherein, The water source includes a reservoir or a connecting element for connecting to a water pipe.

11. The coffee machine (1) according to claim 1 or 2, wherein, The coffee machine in question is an espresso machine.

12. A method for operating a coffee machine according to any one of claims 1 to 5 and 7 to 11, wherein, Each outlet pipe of the coffee machine is equipped with a brewing group valve, which selectively allows or prevents connection of the corresponding outlet pipe to the corresponding brewing group, and wherein... - When the pump (5) and the water heater (7) are turned on, the brewing cycle of the brewing unit (3a) of the coffee machine (1) is triggered; and - Insert a filter holder containing a coffee pouch made of pressed coffee powder into the brewing assembly (3a); The method is characterized by comprising: - Pre-soaking step, in which the valve assembly (13a) corresponding to the brewing group is switched to a position where the valve assembly (13a) connects the auxiliary bypass pipe (11a) of the valve assembly (13a) to the outlet pipe (15a) of the valve assembly (13a), and the brewing group valve (21a) of the brewing group is switched to a position where the brewing group valve (21a) allows the outlet pipe (15a) to connect to the brewing group (3a); - Soaking step, in which the valve assembly (13a) is switched to a position in which the auxiliary feed pipe (9a) of the valve assembly (13a) is connected to the outlet pipe (15a) of the valve assembly (13a), while the brewing group valve (21a) is held in a position in which the outlet pipe (15a) is allowed to connect to the brewing group (3a).

13. The method of claim 12, further comprising a post-soaking step following the soaking step, wherein the valve assembly (13a) is switched again to a position where the valve assembly (13a) connects the auxiliary bypass pipe (11a) of the valve assembly (13a) to the outlet pipe (15a) of the valve assembly (13a), while the brewing group valve (21a) remains in a position where the brewing group valve (21a) allows the outlet pipe (15a) to connect to the brewing group (3a).

Images