Pumping system and method for a beverage production apparatus

Abstract

The present invention presents a pumping system (1) with a preheated reservoir (2), a main pump (4) for pumping a preheated liquid (3) from the reservoir (2), and pressurizing means (5) for pressurizing the reservoir (2). Preferably, the pressurizing means set an absolute pressure of 0.5 to 1 bar in the reservoir (2). The liquid (3) in the reservoir (2) can be heated up to 90 C. or more. The present invention achieves a nearly complete suppression of the phenomenon of cavitation at the main pump entrance, and thus achieves an increased pumping performance at elevated liquid temperatures.

Claims

1. A pumping system for a beverage production apparatus, the pumping system comprising: a reservoir for storing and heating a liquid; a liquid supply configured to supply the liquid to the reservoir; a pressurizer for pressurizing the reservoir, the pressurizer is configured to pressurize the reservoir to an absolute pressure of 0.7 to 1.0 bar, the pressurizer is positioned downstream from the liquid supply, and the pressurizer is positioned upstream from the reservoir, wherein the pressurizer is an air pump; a plurality of beverage extraction units each configured to be operated independently to produce different beverages with different operation parameters; and a plurality of main pumps, wherein each of the plurality of main pumps is dedicated to a corresponding beverage extraction unit and is configured to pump the liquid from the reservoir and into the corresponding beverage extraction unit.

2. The pumping system according to claim 1, wherein the pressurizer is a unit for controlling a liquid level and a liquid temperature in the reservoir.

3. The pumping system according to claim 1, wherein the reservoir is a thermos.

4. The pumping system according to claim 1, wherein each one of the plurality of main pumps is configured to pump the liquid with a respective pressure of the corresponding beverage extraction unit.

5. The pumping system according to claim 1, wherein the reservoir is a low pressure boiler supporting a pressure of about 1 to 3 bar.

6. The pumping system according to claim 1, wherein the plurality of main pumps is configured to receive the liquid from the liquid supply.

7. The pumping system according to claim 1, wherein the reservoir is configured to heat the liquid to a temperature up to about 95 C.

8. The pumping system according to claim 7, wherein each of the plurality of main pumps is configured to pump the liquid heated to the temperature up to about 95 C. with a maximum flow rate of about 100 to 300 ml/min at a maximum output pressure of respectively about 14 to 3 bar.

9. The pumping system according to claim 1, wherein the air pump is configured to control a liquid level in the reservoir.

10. The pumping system according to claim 1, wherein the different operation parameters comprise different liquid pressures.

11. A pumping method for use in a beverage production apparatus, the method comprising: supplying a liquid from a liquid supply to a reservoir; heating the liquid in the reservoir; pressurizing the reservoir with an air pump positioned downstream from the liquid supply and positioned upstream from the reservoir, the air pump configured to pressurize the reservoir to an absolute pressure of 0.7 to 1.0 bar; pumping the liquid from the reservoir with a plurality of main pumps to a plurality of beverage extraction units, each of the plurality of pumps corresponding to a dedicated beverage extraction unit; and operating each of the plurality of beverage extraction units independently to produce different beverages with different operation parameters.

12. The pumping method according to claim 11, wherein the liquid is heated to a temperature up to about 95 C.

13. The pumping method according to claim 11, wherein the different operation parameters comprise different liquid pressures.

Description

(1) The present invention will now be described in more detail in respect to the attached drawings.

BRIEF DESCRIPTION OF THE FIGURES

(2) FIG. 1 shows a state of the art pumping system of a beverage production apparatus.

(3) FIG. 2 shows a state of the art pumping system of a multi-beverage production apparatus.

(4) FIG. 3 shows a phase diagram of water.

(5) FIG. 4 shows a comparison of the pump performance of the state of the art at different liquid temperatures.

(6) FIG. 5 shows a pumping system according to the present invention.

(7) FIG. 6 shows a pumping system according to the present invention.

(8) FIG. 7 shows a pumping system according to the present invention.

(9) FIG. 8 shows a pumping system according to the present invention.

(10) FIG. 9 shows the pump performance at different liquid temperatures and different reservoir pressures.

(11) FIG. 5 shows a pumping system 1 of the present invention. The pumping system 1 includes a reservoir 2, which is configured to store and heat a liquid 3. The reservoir 2 is therefore a preheated reservoir designed for supplying a preheated liquid. The liquid 3 can for instance be water, milk, soup, water-based liquid, chocolate-based liquid, coffee-based liquid, milk-based liquid, or the like. In particular, the liquid 3 can be any liquid that is suitable for preparing a warm or hot beverage.

(12) The pumping system 1 shown in FIG. 5 is in particular useful for a mobile beverage production apparatus. Preferably, the reservoir 2 is a thermos for keeping the liquid hot. However, the reservoir 2 can also be a tank or a boiler. The reservoir 2 can also be equipped with active heating means for heating the liquid 3, for example, a heating coil, heating wire or a heating block. The reservoir 2 can further be equipped or connected to a control unit (not shown) that is suitable to control at least the liquid temperature in the reservoir 2.

(13) The reservoir 2 is connected via a liquid flow circuit, e.g. by pipes 8, to a main pump 4. The main pump 4 is configured to pump the liquid 3 from the reservoir 2. Preferably, the main pump 4 is configured to pump the liquid 3 from the reservoir 2 to a brewing or extraction unit 6 of a beverage production apparatus. The main pump 4 can be a hydraulic pump, a gear pump, a peristaltic pump or any other suitable pump for pumping liquid 3. Preferably, the main pump 4 is connected to the reservoir 2 through a flow meter 7 configured for measuring and controlling the flow rate through the main pump 4. The flow meter 7 can feed back the measured values to the control unit or can itself regulate liquid flow into the main pump 4.

(14) The pumping system 1 is further provided with pressurizing means 5 for pressurizing the reservoir 2 and/or the liquid 3 in the reservoir 2. As shown in FIG. 5, the pressurizing means 5 can be an air pump 51. The air pump 51 is either embedded in the reservoir 2 or is provided upstream of the reservoir 2. The air pump 51 is configured to increase or decrease the pressure in the reservoir 2 when activated. The air pump 51 can be controlled by the control unit.

(15) Preferably, the pressurizing means 5 is configured to achieve an absolute pressure in the reservoir 2 of about 0.5 to 1 bar, more preferably 0.7 to 1 bar. This value of pre-pressure is chosen for increasing the pressure before the main pump inlet to a value that efficiently suppresses cavitation of the liquid 3, taking into account all causes of pressure loss in the liquid circuit between the reservoir 2 and the main pump 4, for example, valves, the flow meter, the pipe 8, etc.

(16) By means of the pressurizing means 5, a heated liquid under pressure is provided within the reservoir 2. That means the absolute pressure in the reservoir 2 is increased. Thereby, the absolute suction pressure at the entrance of the main pump 4 is increased as well, so that the phenomenon of cavitation is suppressed. Thereby, the pumping performance of the main pump 4 can be significantly increased, even at liquid temperatures of 70 C. or more, or even 90 C. or more.

(17) The air pump 51 shown in FIG. 5 is one preferred way to increase the absolute pressure in the reservoir 2. FIG. 6 shows an alternative preferred way for increasing the pressure in the reservoir 2. In particular, in FIG. 6 a mechanical piston 52 is used as pressurizing means 5, which is designed to push onto the reservoir 2. The mechanical piston 52 can, for example, be driven by a motor, and can be controlled by the control unit mentioned above. The mechanical piston could also be driven mechanically, and could for instance be designed to be operated manually by a user.

(18) FIG. 7 shows another preferred way of increasing the pressure in the reservoir 2. Here the pressurizing means 5 is realized by a unit 53, which can be realized by the control unit mentioned above, but can also be a separate unit. The unit 53 is preferably configured to control the liquid level in the reservoir 2. Preferably, the unit 53 is also configured to control the liquid temperature in the reservoir 2. Then the steam pressure caused by heating the liquid 3 can be employed to increase the pressure within the reservoir 2. In order to control the liquid level, the unit 53 is preferably connected to some sort of liquid supply, and is preferably able to increase or decrease the amount of liquid 3 within the reservoir 2.

(19) FIG. 8 shows another pumping system 1 of the present invention, which is particularly advantageous for a multi-beverage production apparatus. The multi-beverage production apparatus can, for example, be an apparatus that is able to produce tea, coffee, espresso and/or chocolate drinks, or the like. Therefore, the multi-beverage production apparatus is preferably equipped with a plurality of brewing or extraction units 6. FIG. 8 shows, for example, four brewing or extraction units 61-64, which can respectively be used to prepare a different beverage.

(20) The pumping system 1 of the present invention comprises in this case a plurality of main pumps 4, wherein each of the main pumps 4 is dedicated to one of the brewing or extraction units 61-64 of the beverage production apparatus. The main pumps 4 are each configured to pump the liquid 3 from the preheated reservoir 2 via pipe 8, preferably through a plurality of flow meters 7, into the respective beverage extraction units 61-64. The main pumps 4 can be designed according to the above description.

(21) The reservoir 2 is preferably a boiler. Therefore, the reservoir 2 is preferably equipped with heating means 21. The heating means 21 can, for example, be a heating wire, a heating coil or a heating block. The reservoir 2 has a liquid inlet and a liquid outlet, and is configured to preferably heat the liquid 3 while the liquid 3 is pumped through the reservoir 2. Preferably, the reservoir 2 is designed as a low-pressure boiler, i.e. a boiler that supports a pressure of up to about 1 to 3 bar. The state of the art typically uses high-pressure boilers, which support pressures of up to about 10 to 15 bar. However, high pressure boilers are much more complicated and expensive to produce.

(22) Again the pumping system 1 includes pressurizing means 5. The pressurizing means 5 is preferably a low-pressure pump 54. The pressurizing means 5 is preferably connected to a liquid supply 9, which is used to supply the liquid 3 into the reservoir 2.

(23) The pumping system 1 of FIG. 8 avoids a costly single main pump 14, as is used in the state of the art. Typically a single main pump 14 delivers a similar extraction pressure for each extraction unit 161-164 (see FIG. 2). Preferably, in the pumping system 1 of the present invention according to FIG. 8, each main pump 4 can be operated independently.

(24) Furthermore, preferably each beverage extraction unit 61-64 can be operated independently and with different operation parameters. Different beverages to be produced from different beverage ingredients require different operation parameters, for example, different pressures of the supplied liquid. Espresso, for example, requires higher liquid pressures, while tea requires lower liquid pressures. Therefore, preferably each extraction unit 61-64 has a dedicated main pump 4, which is selected according to the respective beverage produced by the beverage extraction unit 61-64. In other words, a beverage extraction unit 61 for preparing espresso is connected to a higher-pressure main pump 4. A beverage extraction unit 62 for preparing tea is connected to a cheaper lower-pressure main pump 4. The pump system 1 of the present invention therefore offers a greater versatility than the state of the art.

(25) FIG. 9 shows how with the pumping system 1 and method of the present invention it is possible to achieve a high pumping performance even at elevated liquid temperatures by means of a pressurized reservoir 2. FIG. 9 shows in particular a performance chart (i.e. flow rate vs. output pressure) of a main pump 4 of the present invention. It can be seen that the ideal performance curve, which is achieved by the main pump 4 at ambient temperatures and a non-pressurized reservoir 2, is more or less matched at a liquid temperature of 95 C. when the pressure in the reservoir 2 is increased to 0.7 bar or more.

(26) Due to the suppression of cavitation by increasing the reservoir pressure, the pumping performance of the main pump 4 is increased as well. Thus, it becomes possible to pump a preheated liquid from the reservoir 2 to the extraction unit 6 of a beverage production apparatus, without any loss in pump performance. A heater, a boiler or any other heating means provided after (downstream) the main pump 4 can be omitted. It is further noted that the suppression of cavitation also reflects in the sound of the pump. The main pump 4 is not only able to pump with increased performance (or at least not with a significantly worse performance than at ambient temperatures), but is moreover able to operate more silently.

(27) In summary, the present invention describes a pumping system 1 with a preheated reservoir 2, a main pump 4 for pumping the preheated liquid 3, and pressurizing means 5 for pressurizing the liquid 3 in the reservoir 2. The present invention achieves a nearly complete suppression of the cavitation phenomenon, and thus an increased pumping performance at elevated liquid temperatures.