Device for preparing coffee beverages

Abstract

An apparatus for preparing coffee beverages includes a brewing unit and a beverage outlet connected to the brewing unit via an output pipe. Hot water from a water heater is supplied to the brewing unit under pressure. Freshly brewed coffee beverage is dispensed through the beverage outlet into a drinking vessel positioned below the beverage outlet. A backflow pump is provided, which is connected to the output pipe on the suction side and leads to a discharge port or collection container on the output side, to draw coffee beverage from the coffee pipe and direct it to the discharge port or collection container before, during, or after the brewing process. A controller is used to operate the backflow pump, and the controller is configured to introduce hot water into the output pipe or into the brewing unit and output pipe during the preheating process, and to activate the backflow pump during the preheating process.

Description

[0001] describe

[0002] This invention relates to an apparatus for preparing coffee beverages, comprising a brewing unit and a beverage outlet connected to the brewing unit via an output pipe, wherein hot water from a water heater is supplied to the brewing unit under pressure, and freshly brewed coffee beverage is output to a drinking vessel disposed below the beverage outlet via the beverage outlet.

[0003] Commercially available coffee machines, such as fully automatic coffee machines or espresso machines, have a brewing chamber where coffee grounds are filled and optionally tamped. Hot water is then forced through the coffee grounds under pressure. Some of these machines have an integrated cleaning function during which hot water or rinsing liquid is directed through the brewing chamber. This rinsing liquid can be discharged into a container located below the beverage outlet and manually discarded by the user. However, it is also known that the outlet pipe leading to the beverage outlet is directly connected to the discharge port or collection container via a corresponding reversing valve, ensuring that rinsing liquid does not inadvertently enter the drinking vessel. This reversing valve also allows the outlet pipe to be connected to the discharge port or collection container after the brewing process to prevent residual coffee from dripping. However, the reversing valve (two-position three-way valve) in the outlet pipe has the disadvantage of a high heat capacity, which additionally cools the freshly brewed coffee in the path from the brewing unit to the beverage outlet.

[0004] The object of the present invention is to provide an apparatus for preparing coffee beverages that prevents the freshly brewed coffee from cooling down on its path from the brewing unit to the beverage outlet.

[0005] The objective is achieved through features.

[0006] The aforementioned type of device includes a backflow pump connected to the output pipe on the suction side and leading to an outlet or collection container on the output side, so as to draw coffee beverage from the output pipe and direct it into the outlet or collection container before, during, or after the brewing process. Thus, according to the invention, instead of connecting the output pipe to the discharge pipe via a valve, liquid is drawn from the output pipe and directed into the discharge pipe by negative pressure.

[0007] Furthermore, after a prolonged downtime and before preparing coffee beverages, the device is preheated with hot water using a backflow pump according to the invention. This can be done by briefly guiding a flow of hot water through the brewing unit and the output pipe before filling the brewing unit with coffee powder. Alternatively, the brewing unit can be equipped with its own heating element, thus eliminating the need for preheating. In this case, preheating can be performed only on the output pipe by introducing a flow of hot water into the output pipe via an additional valve. In both cases, according to the invention, the backflow pump is activated during this preheating phase by a matching controller to draw out the hot water used for preheating, so that the hot water is not output via the beverage outlet into the drinking vessel located below the beverage outlet. The backflow pump can be used in the same manner during the cleaning process to draw out the cleaning solution.

[0008] The supply of hot water from the water heater to the brewing unit is suitably achieved by means of a water pump, which delivers water under pressure from a water inlet or from a water tank toward the brewing unit. The water pump can be located in the hot water supply pipe leading from the water heater to the brewing unit. However, the hot water pump is suitably located on the inlet side of the water heater in the cold water supply pipe, thereby delivering cold water to the water heater, which in turn delivers hot water to the brewing unit under the pressure of the pump. The water heater can be constructed as a hot water boiler or as a pass-through heater in a manner known per se.

[0009] In a preferred embodiment, the device has a programmable controller for operating the back-suction pump. This controller enables several functions. Preferably, the back-suction pump is configured to be controlled by the controller so that it draws out any residue of the coffee beverage remaining in the output pipe immediately after the brewing process. This prevents coffee from subsequently dripping from the beverage outlet. Furthermore, this ensures that no cooled coffee beverage remains in the coffee pipe during the next product preparation, thus only freshly brewed coffee beverage is output to the beverage outlet.

[0010] Liquid residue can be emptied from the output pipe after each individual preparation process. Alternatively, the output pipe can be emptied only after a defined pause. This allows multiple coffee beverages to be dispensed sequentially without evacuation. The output pipe is only emptied if no other beverage is being prepared within a certain timeframe. Similarly, the backflow pump can be activated briefly before coffee preparation begins, thereby ensuring no liquid residue remains in the output pipe.

[0011] However, the backflow pump also allows for targeted modification of the flavor of the prepared coffee beverage. To this end, the controller is configured to manipulate the backflow pump so that, during the brewing process, a portion of the newly brewed coffee beverage is selectively drawn out (wegdrainagiert) in a timed manner, and thus this portion is not discharged through the beverage outlet into the user's drinking vessel. This is based on the understanding that different aroma compounds are released from the coffee grounds during this extraction time. Thus, the first part of the coffee (e.g., 0 to 10 seconds) is more acidic, while the last part is more bitter. The backflow pump allows unwanted extraction periods to be discarded during the preparation process. For example, the initial stage can be discarded to achieve less acidity in the final product.

[0012] A particularly advantageous improvement is obtained whereby the controller is configured to change the delivery speed of the backflow pump during operation, thereby altering the amount of coffee beverage output per unit time through the outlet during the brewing process. Thus, by reducing the delivery speed of the backflow pump during a defined extraction period, only a portion of the beverage can be discarded, not entirely. For example, 40% of the coffee beverage can be discarded over a period of 2 to 5 seconds by activating the pump at a reduced delivery speed during this time interval. By specifying the activation time and delivery power, different flavor characteristics can be achieved in the finished coffee beverage.

[0013] In an improved embodiment of the invention, a brewing valve can be installed upstream of the brewing unit in the hot water supply pipe. This brewing valve opens at the start of the brewing process and closes after the brewing process ends. In this case, the controller is configured to activate the backflow pump before, simultaneously with, or after the brewing valve closes. Correspondingly, evacuation of the output pipe occurs shortly before the end of the brewing process, together with the end of the brewing process, or after the brewing process has ended and the brewing valve has closed.

[0014] In a preferred embodiment, a back pressure valve is installed in the output pipe between the brewing unit and the beverage outlet. This back pressure valve allows for targeted adjustment of the pressure within the brewing unit or the flow rate through it. Preferably, the back suction pump branches off from the output pipe downstream of the back pressure valve. This ensures that the brewing pressure of the brewing unit does not act on the back suction pump during the brewing process. Furthermore, it allows for evacuation of the back suction pipe up to the beverage outlet without the resistance of the back pressure valve.

[0015] In an alternative embodiment, the backflow pump may not be directly connected to the output pipe, but may be connected upstream of the brewing unit to a hot water supply pipe or to the outlet (Abgang) of a brewing valve that can be connected to a hot water supply pipe. In this case, the coffee beverage can be drawn back through the brewing unit during the operation of the backflow pump. Thus, the backflow pump is connected to the output pipe via the brewing unit.

[0016] In a preferred design, the backflow pump is designed as a peristaltic pump. Such peristaltic pumps have proven particularly robust against hot and potentially corrosive liquids (such as acidic coffee) and against deposits that may form over time.

[0017] Further advantages and embodiments of the present invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Wherein:

[0018] Figure 1 A flow diagram of a coffee preparation apparatus with a back-suction pump connected to an output pipe in the first embodiment is shown.

[0019] Figure 2 A second embodiment is shown, which has an additional back pressure valve disposed in the output pipe.

[0020] Figure 3 An alternative embodiment is shown, which has a back pressure valve disposed in the suction pipe.

[0021] Figure 4 An embodiment of a coffee preparation apparatus is shown, having a backflow pump connected upstream of the brewing unit via a brewing valve.

[0022] Figure 5 An alternative embodiment is shown, which has a backflow pump connected between the brewing assembly and the brewing valve.

[0023] Figure 6 Another alternative embodiment is shown, which has a backflow pump connected upstream of the brewing valve, and

[0024] Figure 7 An embodiment is shown, featuring a heating element in the brewing unit and a valve for preheating the output pipe.

[0025] Figure 1The diagram shows a so-called water circuit diagram of the structure of an apparatus for preparing coffee beverages, which can be used in fully automatic coffee machines or espresso machines. The apparatus includes a brewing unit 1, a hot water boiler 2, a water pump 3 on the delivery side, and a beverage outlet 4 for dispensing freshly brewed coffee beverage, which is connected to the brewing unit 1 via an outlet pipe 5. Additionally, a backflow pump 6 is connected to the outlet pipe 5, leading on the delivery side to an outlet 7 or a collection container. A brewing valve 8, designed as a two-position three-way valve, is provided in the hot water supply pipe between the hot water boiler 2 and the brewing unit 1. The brewing valve selectively connects the hot water pipe from the hot water boiler 2 to the brewing unit 1, or connects the brewing unit 1 to the outlet 7 or a corresponding collection container.

[0026] A main water valve 10 is located upstream of the water pump 3 along the flow direction, through which the brewing device is connected to the drinking water supply pipe 11. On the delivery side, the pump 3 is connected to the supply port of the hot water boiler 2 via a flow sensor 12, also commonly referred to as a flow meter, and a check valve 13. Hot water is supplied from the hot water boiler 2 to the brewing unit 1 by pressurizing the hot water boiler 2 using the water pump 3. A controller 15 with a user interface 16 controls the functions of the brewing device and its components. The controller can be implemented here by a correspondingly programmed microcontroller, thereby enabling further control and adjustment processes within the fully automatic coffee machine.

[0027] Brewing unit 1 includes a brewing chamber and preferably a heating element in a manner known per se (see [link to original text]). Figure 7 (20) Freshly ground coffee powder is filled into the brewing chamber in portions, and the brewing unit can be preheated and kept warm using a heating element. For example, a brewing unit that can be used within the scope of this invention is described in EP 2561778 A1, and the full text of that document is cited here to avoid unnecessary repetition.

[0028] The brewing unit is designed to be opened to dispense portions of freshly ground coffee powder, pre-ground in the grinding mechanism of the fully automatic coffee machine. Furthermore, after the brewing process, residual coffee grounds can be discarded into the coffee grounds container (Tresterbehälter) when the brewing unit is opened. The brewing unit also features a movable piston (not shown) that compacts the dispensed coffee powder against the brewing filter located in the brewing chamber. After the piston retracts, pressurized brewing water can flow through this compacted coffee powder.

[0029] Freshly brewed coffee flows from brewing unit 1 to beverage outlet 4 via output pipe 5, and from there into drinking vessel 14 located below the beverage outlet. After the brewing process is complete, the back-suction pump 6 can be activated via controller 15. The back-suction pump sucks out the coffee beverage remaining in output pipe 5 and directs it to outlet 7 or optionally to a collection container connected to the pump. This prevents coffee from continuing to drip from beverage outlet 4. The remaining amount of coffee beverage still in the output pipe can thus be completely and reliably emptied. This has the following advantages: the initiation of the next product's production (outflow action) proceeds without dripping or splashing because the gas / coffee mixture can be completely expelled. The residual amount of coffee does not additionally cool the next product. Furthermore, the flavor of the next product is not adversely affected by the residual amount of coffee beverage.

[0030] Furthermore, the flavor profile of the beverage can be selectively altered via the backflow pump 6 by discarding coffee during a defined extraction period, i.e., drawing it into the outlet 7. For example, the initial extraction phase can be discarded to achieve a lower acidity. Additionally, the pump can regulate the amount of coffee dispensed into the drinking vessel during the defined extraction period. Thus, for example, 40% of the coffee can be discarded during the 2-5 second extraction period by adaptively adjusting the delivery speed of the backflow pump 6.

[0031] The functions of the coffee preparation apparatus are determined by the control unit 15. This control unit reads various sensors, such as flow sensor 12, and controls valves 8 and 10, pumps 3 and 6, and brewing unit 1. Of course, sensors for pressure, temperature, flow rate, etc., not shown here for clarity, can also be installed; the measurements from these sensors are read by the control unit 15.

[0032] Furthermore, the control unit 15 controls the automatic cleaning process, during which rinsing fluid is delivered through the rinsing unit 1 and the output pipe 5, and specifically, the back suction pump 6 is activated to draw the rinsing fluid from the output pipe 5 and direct it into the outlet 7. The control unit 15 also controls the heating process, during which hot water is delivered through the rinsing unit 1 and the output pipe 5 to preheat the rinsing unit and the output pipe. In this case, the back suction pump 6 is also activated to draw rinsing water from the output pipe into the outlet 7.

[0033] The following examples illustrate that... Figure 1 The coffee preparation apparatus shown here is a variation and improvement. Only the flow path starting from the hot water boiler 2 is shown. Figure 2In the illustrated embodiment, an adjustable back pressure valve 9 is additionally provided in the output pipe 5. This back pressure valve is preferably a needle valve, which is motor-operated and creates flow resistance in the output pipe, so that the water pressure applied to the brewing unit 1 decreases not only at the coffee cake contained in the brewing chamber, but also at the back pressure valve 9 depending on its open state. The back pressure valve 9 can be adjusted by means of the controller 15 to achieve a specific flow rate or a specific total flow time of a predetermined amount of brewing water, or a specific pressure in the brewing unit 1. A back suction pump 6 is suitably connected downstream of the back pressure valve 9 to the output pipe 5, so that the back suction pump can draw freshly brewed coffee beverage from the output pipe 5 independently of the open state of the back pressure valve 9, either after the brewing process is completed or during the brewing process.

[0034] exist Figure 3 In the alternative embodiment shown, the back-suction pump 6 is connected upstream of the back-suction pipe 5 to the back-suction valve 9, so that freshly brewed coffee beverage can be drawn directly downstream of the brewing unit 1. To empty the output pipe 5, the back-suction valve 9 can be suitably fully opened after the brewing process is complete, so that the coffee beverage can be reliably and quickly drawn out by the back-suction pump 6 without additional resistance.

[0035] exist Figure 4 In the illustrated embodiment, the backflow pump 6 is connected to the third port of the brewing valve 8 (a two-position three-way valve), such that when the brewing valve is closed, the brewing unit 1 can be emptied towards the outlet 7 via the backflow pump 6. The output pipe 5 can here be emptied through the brewing unit 1. For this purpose, the brewing piston of the brewing unit 1 is suitably retracted, and the coffee grounds contained in the brewing chamber are discarded into the coffee grounds container (not shown).

[0036] Alternatively, such as Figure 5 As shown, the backflow pump 6 is also connected in the connecting pipe between the brewing valve 8 and the brewing unit 1. In this case, when the brewing valve is closed, the fluid remaining in the brewing unit 1 can also be drawn out by the backflow pump 6 and introduced into the discharge port 7.

[0037] Finally, Figure 6 One embodiment is shown in the figure, in which the back-suction pump 6 is connected upstream of the brewing valve 8. In this case, after the brewing process is completed, the brewing valve is first closed and the fluid contained in the supply pipe is discharged into the outlet via the brewing valve. Next, the brewing valve can be reopened so that the coffee beverage remaining in the brewing unit 1 and the output pipe 5 can be drawn back by the back-suction pump 6 and discharged into the outlet 7.

[0038] As already explained, the back-suction pump 6 is preferably designed as a peristaltic pump so that the pump's moving parts do not come into contact with hot and potentially corrosive coffee beverages. Alternatively, other, equally robust pump types may be used.

[0039] Figure 7 An embodiment is shown, which substantially corresponds to... Figure 1 The embodiment shown is illustrated. Additionally, an electric heating element 20 for the brewing unit 1 is shown, which can be used to preheat the brewing unit. Furthermore, a reversing valve 17 is provided downstream of the brewing unit 1 in the output pipe. During normal operation, the reversing valve connects the output of the brewing unit 1 to the output pipe 5. After a long downtime, to preheat the output pipe, the controller 15 can switch the valve 17 to direct hot water flow through the output pipe 5. The input 18 of the reversing valve 17 is therefore connected to a water heater, such as... Figure 1 The hot water boiler 2 is connected. During this heating process, the backflow pump 6 is activated via controller 15 to draw out the hot water used for preheating, thus preventing the hot water from being output through beverage outlet 4 into the drinking vessel 14 located below the beverage outlet. By preheating the output pipe 5 and the brewing unit 1, the freshly brewed coffee beverage is prevented from cooling in the coffee machine before it reaches the drinking vessel 14. The operation of the backflow pump 6 prevents the output pipe 5 from being filled with water at the start of coffee extraction during preheating, which could then be output into the drinking vessel and dilute the coffee beverage during extraction.

Claims

1. An apparatus for preparing a coffee beverage, the apparatus having a brewing unit (1) and a beverage outlet (4) connected to the brewing unit (1) via an output pipe (5), wherein hot water from a water heater (2) can be supplied to the brewing unit under pressure, and the freshly brewed coffee beverage can be output through the beverage outlet to a drinking vessel (14) positioned below the beverage outlet. Its features are, The device has a backflow pump (6) that is connected to the output pipe (5) on the suction side and to the outlet (7) or collection container on the output side to draw coffee beverage from the output pipe (5) and direct it to the outlet (7) or collection container before, during or after the brewing process. The device has a controller (15) for operating the backflow pump (6) and is configured to introduce hot water into the output pipe (5) or the brewing unit (1) and the output pipe (5) during the preheating process and to start the backflow pump (6) during the preheating process.

2. The apparatus according to claim 1, wherein, The controller (15) is configured to activate the backflow pump (6) so that the residue of coffee beverage remaining in the output pipe (5) after the brewing process is sucked away.

3. The apparatus according to claim 1, wherein, The controller (15) is configured to activate the backflow pump (6) so that a portion of the newly brewed coffee beverage is selectively and timed to be discarded during the brewing process.

4. The apparatus according to claim 3, wherein, The controller (15) is configured to change the delivery speed of the backflow pump (6) during operation in order to change the amount of coffee beverage output per unit time through the outlet (4) during the brewing process.

5. The apparatus according to any one of claims 1 to 4, the apparatus having a brewing valve (8) disposed upstream of the brewing unit (1) in a hot water supply pipe, the brewing valve opening at the start of the brewing process and closing after the brewing process, the controller (15) being configured to start the backflow pump (6) before, simultaneously with or after the brewing valve (8) is closed.

6. The apparatus according to claim 1, wherein the apparatus has a back pressure valve (9) disposed in the output pipe (5) between the brewing unit (1) and the beverage outlet (4).

7. The apparatus according to claim 6, wherein, The suction pipe of the back suction pump (6) branches off from the output pipe (5) downstream of the back pressure valve (9).

8. The apparatus according to claim 1, wherein, The suction pipe of the back suction pump (6) is connected upstream of the brewing unit (1) to a hot water supply pipe, so that coffee beverage is back-suctioned through the brewing unit (1) during the operation of the back suction pump (6).

9. The apparatus according to claim 5, wherein, The suction pipe of the back suction pump (6) is connected to the outlet of the brewing valve (8) which can be connected to the hot water supply pipe, so that coffee beverage is back-suctioned through the brewing unit (1) during the operation of the back suction pump (6).

10. The apparatus according to claim 1, wherein, The back-suction pump (6) is a peristaltic pump.

11. The apparatus according to claim 1, wherein, The controller (15) is configured to briefly activate the flow of hot water through the brewing unit (1) and the output pipe (5) before filling the brewing unit (1) with coffee powder to implement a preheating process.

12. The apparatus according to claim 1, wherein, The brewing unit (1) is equipped with a heating element (20), and the controller (15) is configured to activate the hot water flow through the output pipe (5) via a valve (17) to implement a preheating process.

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