Coffee beverage preparation device

Abstract

In a coffee beverage preparation device having an extraction device capable of supplying hot water under pressure from a water heater and a beverage outlet connected to the extraction device via a discharge pipe, and capable of supplying a freshly extracted coffee beverage via the beverage outlet to a beverage container arranged below the beverage outlet, a suck-back pump is provided which is fluidly connected to the outlet pipe on its suction side and opens on its pressure side into the outlet or a collection container, thereby sucking the coffee beverage from the coffee tube and directing it into the outlet or a collection container before, during or after the extraction process. A control device is used for controlling the suck-back pump and is configured to operate the suck-back pump during a pre-heating process in which hot water is directed into the outlet pipe or the extraction device and into the outlet pipe.

Description

[Technical field]

[0001] The present invention relates to a coffee beverage preparation device having an extraction device capable of supplying hot water under pressure from a water heater and a beverage discharge part connected to the extraction device via a discharge pipe, and capable of supplying a freshly extracted coffee beverage via the beverage discharge part to a beverage container arranged below the beverage discharge part. [Background technology]

[0002] Commercially available coffee makers, such as fully automatic coffee makers or espresso machines, have a brewing chamber into which ground coffee is filled, which is compressed if necessary and then hot water passes under pressure. Sometimes such coffee makers have an integrated cleaning function during which hot water or rinsing liquid passes through the brewing chamber. The rinsing liquid is discharged into a container arranged below the beverage outlet and can be manually discarded by the user. However, it is also known to connect the outlet pipe leading to the beverage outlet directly to a discharge or to a collection container via a suitable changeover valve, so that the rinsing liquid does not accidentally enter the beverage container. It is also possible to connect the outlet pipe to the discharge or to the collection container via such a changeover valve after the end of the brewing process in order to prevent residual coffee dripping out. However, a changeover valve (3 / 2 way valve) arranged in the outlet pipe has the disadvantage of a relatively large heat capacity, which causes the freshly brewed coffee to be further cooled on the way from the brewing device to the beverage outlet. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention aims to provide a machine for preparing a coffee beverage, which avoids cooling of the freshly brewed coffee on its way from the brewing device to the beverage outlet. [Means for solving the problem]

[0004] This problem is solved by the features of claim 1. Advantageous embodiments result from the dependent claims.

[0005] In a device of the type mentioned at the beginning, a suck-back pump is provided which is fluidly connected on the suction side to the outlet line and opens on the pressure side into an outlet or a collection vessel, so as to suck the coffee beverage from the coffee tube and direct it to said outlet or a collection vessel before, during or after the brewing process, so that instead of connecting the outlet line to a drain via a valve, within the scope of the invention the liquid is sucked from the outlet line by negative pressure and directed to the drain.

[0006] Furthermore, after a relatively long standstill time, the device is preheated with hot water using the suck-back pump according to the invention before the preparation of the coffee beverage. This can be done on the one hand by passing a hot water flow through the brewing device and the discharge line for a short time before filling the brewing device with coffee powder. Alternatively, preheating is not necessary by providing the brewing device with its own heater. In this case, it is possible to preheat only the discharge line by introducing a hot water flow into the discharge line via an additional valve. In the present invention, in each case, during such a preheating phase, the suck-back pump is operated via an associated control in order to suck in the hot water used for preheating and to prevent it from being discharged via the beverage outlet into a beverage container arranged below it. Similarly, the suck-back pump can be used to suck in cleaning liquid during a cleaning process.

[0007] The supply of hot water from the water heater via the hot water pipe to the extraction device is expediently carried out by means of a water pump, which supplies water under pressure from a water pipe or a water tank in the direction of the extraction device. The water pump can be arranged in the hot water pipe leading from the water heater to the extraction device. However, it is expedient that the water pump is arranged in the cold water pipe of the water heater at the inlet side of the water heater, thereby supplying cold water to the water heater, which in turn supplies hot water under the pressure of the pump to the extraction device. The water heater can be formed as a hot water boiler or a flow heater in a manner known per se.

[0008] In a preferred embodiment, the device comprises a programmable control device for controlling the suck-back pump. By means of such a control device, various functions can be realized. Preferably, the suck-back pump is controlled by the control device in such a way that the coffee beverage residues remaining in the outlet tube after the brewing process are sucked out. This prevents coffee from dripping out of the beverage outlet. This also ensures that only freshly brewed coffee beverage is delivered to the beverage outlet by ensuring that no cold coffee beverage is present in the coffee tube during the preparation of the next product.

[0009] The suction of liquid residues from the discharge line can be performed after each individual brewing process. Alternatively, the discharge line can be emptied only after a predefined pause time. Thus, it is possible to dispense several coffee beverages directly in succession without suction. The discharge line is emptied only when no other beverages are to be brewed for some time. Similarly, it is possible to ensure that there are no liquid residues in the discharge line by operating the suck-back pump for a short time before the start of coffee brewing.

[0010] In addition, however, it is also possible to tailor the taste of the coffee beverage prepared with the aid of the suck-back pump. For this purpose, the control device is arranged to control the suck-back pump in such a way that during the coffee beverage extraction process, portions of the freshly extracted coffee beverage are selectively sucked out ("discharged") in a time-controlled manner, so that they are not delivered via the beverage outlet into the user's beverage container. This is based on the knowledge that different aroma carriers are released from the coffee grounds over the extraction time. Thus, while the first portions of the coffee (for example from 0 to 10 seconds) are rather sour, the last portions are rather bitter. The suck-back pump therefore allows undesired periods of extraction during the preparation process to be discharged. For example, a less sour taste in the final product can be achieved by discharging the initial phase.

[0011] A particularly preferred development is obtained if the control device is arranged to vary the amount of coffee beverage delivered per unit time from the outlet during the brewing process by controlling the suck-back pump to vary its delivery speed during operation. Thus, by reducing the delivery speed of the suction pump, it is possible to only partially, rather than completely, deliver each beverage component during a given brewing period. Thus, for example, during a period of 2 to 5 seconds, 40% of the coffee beverage can be delivered by operating the pump at a reduced delivery speed in said time interval. By presetting the operating times and delivery speeds, different taste characteristics of the finished coffee beverage can be achieved.

[0012] In a further development of the invention, an extraction valve can be provided in the hot water line upstream of the extraction device, which is opened to start the extraction process and closed after the extraction process is finished, the control device can then be configured to activate the suck-back pump before, simultaneously with or after closing the extraction valve, so that the outlet line is emptied immediately after the extraction process is finished, simultaneously with the extraction process or only after the extraction process is finished and the extraction valve is closed.

[0013] In a preferred development, a counter pressure valve is arranged in the delivery line between the brewer and the beverage outlet, via which the pressure in the brewer or the flow rate through the brewer can be adjusted as desired. Advantageously, the suck-back pump branches off upstream of the delivery line downstream of the counter pressure valve, so that on the one hand the extraction pressure of the brewer is not applied to the suck-back pump during the brewing process. On the other hand, the suck-back line to the beverage outlet can be sucked until empty without the resistance of the counter pressure valve.

[0014] In an alternative embodiment, the suck-back pump may be connected not directly to the discharge line but to the hot water line upstream of the brewing device or to an outlet of the brewing valve connectable to the hot water line, in which case the coffee beverage may be sucked back through the brewing device upon actuation of the suck-back pump, and the suck-back pump is thus in fluid communication with the discharge line via the brewing device.

[0015] In a preferred embodiment, the suck-back pump is configured as a peristaltic pump, which has been found to be particularly robust against hot and possibly corrosive liquids (acidic coffee) as well as deposits that may form over time.

[0016] Further advantages and features of the invention will become apparent from the following detailed description of exemplary embodiments with reference to the drawings. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a flow diagram of a coffee brewing machine having a suck-back pump connected to a discharge line in a first example embodiment; [Diagram 2] FIG. 13 shows a second example embodiment having an additional back pressure valve disposed in the discharge line. [Diagram 3] FIG. 13 illustrates an alternative embodiment having a back pressure valve located in the suction line. [Figure 4] FIG. 1 shows an example embodiment of a coffee brewing device having a suck-back pump connected upstream of the brewer via a brewing valve. [Diagram 5] FIG. 13 illustrates an alternative embodiment having a suckback pump connected between the extraction assembly and the extraction valve. [Figure 6] FIG. 13 illustrates a further alternative example embodiment having a suckback pump connected upstream of the extraction valve. [Figure 7] FIG. 13 illustrates an example embodiment having a heater and valve in the extractor to preheat the discharge line. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] In Fig. 1 the structure of the preparation device for the respective coffee beverage is shown in a so-called water flow system, which can be used, for example, in a fully automatic coffee maker or espresso machine. The preparation device comprises an extractor 1, a hot water boiler 2, an inlet water pump 3 and a beverage outlet 4 for supplying the respective freshly extracted coffee beverage, which is connected to the extractor 1 via an outlet pipe 5. A suck-back pump 6 is further connected to the outlet pipe 5, which opens on the pressure side into an outlet 7 or into a collection vessel. In the hot water supply pipe between the hot water boiler 2 and the extractor 1, an extractor valve 8 is arranged, which is configured as a 3 / 2-way valve. The extractor valve alternately connects the hot water pipe from the hot water boiler 2 to the extractor 1, or between the extractor 1 and the outlet 7 or a corresponding collection vessel.

[0019] A main water valve 10 is arranged upstream of the water pump 3 in the flow direction, via which the preparation device is connected to a drinking water pipe 11. On the pressure side, the pump 3 is connected to the inlet of the hot water boiler 2 via a flow sensor 12, often also called flow meter, and a check valve 13. The water pump 3 pressurizes the hot water boiler 2, from which hot water is supplied to the brewing device 1. A control device 15 with a user interface 16 controls the function of the preparation device and its components. The control device can be realized by a correspondingly programmed microprocessor, which can also be used to implement other control and regulation processes in the fully automatic coffee maker.

[0020] In a manner known per se, the brewing device 1 comprises a brewing chamber which is filled with portioned, freshly ground coffee powder, and preferably a heater (see figures 7, 20) making it possible to preheat and keep the brewing device warm. A brewing device which can be used within the scope of the present invention is for example described in EP 2 561 778 A1, to which reference is made in full here to avoid unnecessary repetition.

[0021] The brewing device is configured such that it can be opened to fill the portioned amount of ground coffee in advance in the mill of the automatic coffee maker. In addition, when the brewing device is open, the coffee grounds remaining after the brewing process can be discharged into a coffee container after use. The brewing device further comprises a movable piston (not shown) which compresses the filled coffee grounds against a brewing filter located in the brewing chamber. After retracting the piston, brewing water under pressure can flow through the thus compressed coffee grounds.

[0022] From the brewing device 1, freshly extracted coffee beverage flows via the discharge pipe 5 to the beverage outlet 4 and from there to the beverage container 14 arranged below the beverage outlet. After the end of the brewing process, the suck-back pump 6 can be activated via the control device 15, which sucks the coffee beverage remaining in the discharge pipe 5 and introduces it into the outlet 7 or into a collection container connected to the pump, if necessary. Thus, dripping of coffee from the beverage outlet 4 is prevented. It is thus possible to completely and reliably empty the remaining amount of coffee beverage still remaining in the discharge pipe. This has the following advantages: no dripping or splashing occurs during the start-up (dispensing) of the next product, since the gas-coffee mixture can be completely discharged. The remaining amount of coffee does not further cool the next product. Furthermore, the remaining amount of coffee beverage does not impair the taste of the next product.

[0023] In addition, the taste of the beverage dispensed by means of the suck-back pump 6 can be varied according to purpose by dispensing, i.e. sucking into the outlet 7, during each specific extraction period. For example, it is possible to reduce sourness by dispensing in the start-up phase. Furthermore, it is possible to adjust the amount of coffee dispensed to the beverage container during each defined extraction period using the pump. Thus, for example, between 2 and 5 seconds, 40% of the coffee can be dispensed by appropriately adjusting the delivery speed of the suck-back pump 6.

[0024] The functioning of the coffee preparation device is determined by the control device 15, which reads various sensors, e.g. the flow meter 12, and controls the valves 8 and 10, the pumps 3 and 6 and the brewing device 1. Further sensors for pressure, temperature, flow etc., not shown here for clarity, can of course be provided, whose respective measurements are read out by the control device 15.

[0025] Furthermore, the control device 15 controls an automatic cleaning process in which rinsing liquid is supplied through the brewer 1 and the discharge pipe 5, in particular by operating the suck-back pump 6 to suck the rinsing liquid from the discharge pipe 5 and introduce it into the discharge section 7. Similarly, the control device 15 controls a heating process in which hot water is supplied through the brewer 1 and the discharge pipe 5 to preheat the discharge pipe. Even in this case, the suck-back pump 6 is operated to suck the rinsing liquid from the discharge pipe into the discharge section 7.

[0026] In the following embodiments, variants and variants of the coffee preparation device shown in FIG. 1 are described. In each case, only the fluid paths from the hot water boiler 2 are shown. In the embodiment shown in FIG. 2, an adjustable counter pressure valve 9 is additionally provided in the discharge pipe 5. The counter pressure valve is preferably realized as a needle valve controlled via a motor and provides a flow resistance in the discharge pipe, so that the water pressure applied to the brewing device 1 does not only fall above the coffee grounds contained in the brewing chamber, but also falls at the counter pressure valve 9 depending on the opening state of the counter pressure valve 9. By means of the control device 15, the counter pressure valve 9 can be adjusted so that a predetermined total flow rate or a predetermined pressure is obtained in the brewing device 1 for a predetermined flow rate or a preset amount of brewed water. It is reasonable to connect the suck-back pump 6 to the discharge pipe 5 downstream of the counter pressure valve 9 so that the discharge pipe 5 can be used to suck freshly brewed coffee beverage after the end of the brewing process or even during the brewing process, regardless of the opening state of the counter pressure valve 9.

[0027] In an alternative embodiment example, illustrated in figure 3, the suck-back pump 6 is connected to the suck-back pipe 5 upstream of the counter pressure valve 9, so that the freshly extracted coffee beverage can be sucked directly downstream of the device 1. To empty the outlet 5, it is reasonable to ensure that the counter pressure valve 9 can be fully opened after the end of the extraction process, so that the coffee beverage can be sucked by the suck-back pump 6 without additional resistance and therefore reliably and quickly.

[0028] In the embodiment illustrated in Fig. 4, the suck-back pump 6 is connected to a third connection of the extraction valve 8 (3 / 2-way valve) in such a way that, with the extraction valve closed, the brewer 1 can be emptied via the suck-back pump 6 in the direction of the outlet 7. The outlet 5 can then be sucked to empty through the brewer 1. For this purpose, it is expedient to retract the brewing piston of the brewer 1 and to expel the coffee grounds contained in the brewing chamber into a coffee container (not shown) after use.

[0029] 5, the suck-back pump 6 may alternatively be connected in a connecting pipe between the extraction valve 8 and the extraction device 1. Even in this case, when the extraction valve is closed, the liquid remaining in the extraction device 1 can be sucked through the suck-back pump 6 and introduced into the discharge part 7.

[0030] Finally, in figure 6 an embodiment is shown in which the suck-back pump 6 is connected upstream of the extraction valve 8. In this case, after the end of the extraction process, the extraction valve can first be closed so that the liquid contained in the supply line can be discharged via the extraction valve 8 to the outlet. The extraction valve can then be opened again so that the coffee beverage remaining in the brewing device 1 and in the outlet line 5 can be sucked back by the suck-back pump 6 and discharged to the outlet 7.

[0031] As previously mentioned, the suckback pump 6 is preferably configured as a peristaltic pump to prevent the moving parts of the pump from coming into contact with the hot and potentially corrosive coffee beverage, however, alternatively other, equally robust pump types could be used.

[0032] In FIG. 7, an embodiment example is shown which substantially corresponds to the embodiment example shown in FIG. 1. Additionally, an electric heater 20 of the brewing device 1 is shown, by means of which the brewing device can be preheated. Furthermore, a changeover valve 17 is arranged downstream of the brewing device 1 in the discharge line, which in normal operation connects the outlet of the brewing device 1 with the discharge line 5. To preheat the discharge line after a relatively long stop time, the valve 17 is switched by the control device 15 to allow a hot water flow to pass through the discharge line 5. For this purpose, an inlet 18 of the changeover valve 17 is connected to a water heater, for example the hot water boiler 2 in FIG. 1. During the preheating process, the suck-back pump 6 is activated via the control device 15 to suck in the hot water used for preheating, so that it is not discharged via the beverage outlet 4 into a beverage container 14 arranged below the beverage outlet. Pre-heating the discharge pipe 5 and the brewing device 1 prevents the freshly brewed coffee beverage from cooling down while still in the coffee maker before it reaches the beverage container 14. Activating the suck-back pump 6 during pre-heating prevents the discharge pipe 5 from being filled with water at the start of coffee brewing, which may be discharged into the beverage container during coffee brewing and dilute the coffee beverage.

Claims

1. A coffee beverage preparation device comprising an extraction device (1) capable of receiving hot water under pressure from a water heater (2) and a beverage outlet (4) connected to the extraction device (1) via an outlet pipe (5), the device being capable of supplying a freshly extracted coffee beverage via the beverage outlet to a beverage container (14) arranged below the beverage outlet, a suck-back pump (6) connected in fluid communication with the discharge pipe (5) on the suction side and opening on the pressure side into a discharge part (7) or into a collection container, thereby sucking the coffee beverage from the discharge pipe (5) into the discharge part (7) or into a collection container before, during or after the brewing process, and a control device (15) for controlling the suck-back pump (6), The device is characterized in that the control device (15) is configured to introduce hot water into the discharge pipe (5) or into the brewing device (1) and the discharge pipe (5) during a pre-heating process to operate the suck-back pump (6) during the pre-heating process.

2. 2. Apparatus according to claim 1, characterized in that the control device (15) is formed to control the suck-back pump (6) in such a way that residues of the coffee beverage remaining in the discharge pipe (5) after the extraction process are sucked away.

3. 3. Apparatus according to claim 2, characterized in that the control device (15) is adapted to control the suck-back pump (6) in such a way that portions of freshly brewed coffee beverage are purposefully dispensed in a time-controlled manner during the brewing process of the coffee beverage.

4. 4. The device according to claim 3, characterized in that the control device (15) is adapted to vary the amount of coffee beverage delivered per unit time from the outlet (4) during the brewing process by controlling the suck-back pump (6) to vary its delivery speed during operation.

5. 5. The device according to claim 4, further comprising an extraction valve (8) arranged in a hot water pipe upstream of the extraction device (1), which is opened to start the extraction process and closed after completion of the extraction process, and the control device (15) operates the suck-back pump (6) before, simultaneously with or after closing the extraction valve (8).

6. 6. The device according to claim 1, further comprising a back pressure valve (9) arranged in the delivery pipe (5) between the extraction device (1) and the beverage delivery part (4), the suction pipe of the suck-back pump (6) preferably branches off from the delivery pipe (5) downstream of the back pressure valve (9).

7. Device according to any one of claims 1 to 5, characterised in that the suction line of the suck-back pump (6) is connected upstream of the brewing device (1) to a hot water line or to the outlet of a brewing valve (8) connectable to said hot water line, such that coffee beverage is sucked back through the brewing device (1) upon activation of the suck-back pump (6).

8. Device according to any one of the preceding claims, characterized in that the suck-back pump (6) is a peristaltic pump.

9. Device according to any one of claims 1 to 5, characterised in that the control device (15) is adapted to activate the hot water flow through the brewing device (1) and the discharge pipe (5) for a short period of time before filling the brewing device (1) with coffee grounds in order to carry out a pre-heating process.

10. 6. Apparatus according to any one of claims 1 to 5, characterised in that the extraction device (1) is provided with a heater (20) and the control device (15) is adapted to activate a hot water flow through the discharge pipe (5) via a valve (17) in order to carry out a pre-heating process.

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