Coffee machine for portion capsules

Abstract

An extraction appliance with a brewing module for forming a brewing chamber for a portion capsule, with a water feed comprising a pump and a water heater for feeding water under pressure to the brewing chamber. The extraction appliance includes a control for the pump that can be integrated into the pump or be present at least partly externally of the pump, as well as a device for measuring the fluid flow into the brewing chamber. The control is configured such that a pump power of the pump is dependent on the fluid flow, and specifically such that given a lower fluid flow, the pump power is reduced in comparison to a greater fluid flow.

Claims

1. An extraction appliance for preparing an extraction product from an extraction material contained in a capsule, said extraction appliance comprising: a brewing module that forms a brewing chamber for the capsule, a water feed for feeding water under pressure to the brewing chamber, the water feed comprising a pump; a controller; and, a device that measures a fluid flow of liquid flowing into the brewing chamber; wherein the controller is configured and connected to the pump so as to control a pump power of the pump in a manner dependent on the measured fluid flow; and wherein the controller is configured to reduce the pump power if the fluid flow falls below a predetermined threshold.

2. The extraction appliance according to claim 1, comprising a water heater and a temperature sensor, wherein the controller is configured to activate the water heater dependent on a temperature measured by the temperature sensor.

3. The extraction appliance according to claim 1, wherein the controller is configured so as to control the pump power dependent solely on the fluid flow.

4. The extraction appliance according to claim 1, wherein the device that measures the fluid flow into the brewing chamber is a flow sensor that is arranged at a feed conduit of the water feed.

5. The extraction appliance according to claim 1, further comprising a capsule recognition module for recognizing the capsule, wherein the controller is configured to control the pump power of the pump dependent on the measured fluid flow in accordance with a program, said program being selected based upon a nature of the recognized capsule.

6. The extraction appliance according to claim 1, wherein the pump power is reduced by a nonzero factor K.sub.0 as soon as the fluid flow has fallen short of the predetermined threshold.

7. The extraction appliance according to claim 1, wherein the pump power is adapted by a correcting a power supplied to the pump by multiplying with a correction factor K on falling short of an upper threshold value, wherein said correction factor is a continuous linear function of the fluid flow, at least in an interval.

8. The extraction appliance according to claim 7, wherein the pump power, on falling short of the upper threshold value, runs between 1 and a minimum correction factor K.sub.m at a lower threshold value, in a manner depending on the fluid flow, wherein the value of minimum correction factor K.sub.m is between 0.3 and 0.8.

9. The extraction appliance according to claim 1, wherein the pump power is adapted by a correction factor K on falling short of an upper threshold value, said correction factor being a continuous, non-linear function of the fluid flow.

10. In combination, an extraction appliance according to claim 1 and a portion capsule with an extraction material, wherein a geometry of the portion capsule is matched to the brewing chamber and comprises a capsule wall able to be pierced.

11. The combination according to claim 10, wherein the capsule wall consists of plastic.

12. A method for operating an extraction appliance according to claim 1 for preparing an extraction product from an extraction material contained in a capsule, with a brewing module for forming a brewing chamber for the capsule, with a water feed comprising a pump for feeding water under pressure to the brewing chamber, the method comprising the steps of: measuring a fluid flow into the brewing chamber; and, controlling a power supplied to the pump in a manner depending on the measured fluid flow during a brewing process; wherein the step of controlling is carried out in a manner that the pump power is reduced when the fluid flow falls below a predetermined threshold.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiment examples are hereinafter described by way of drawings. The same reference numerals in the drawings indicate equal or analogous elements. The drawings may show elements that correspond to one another, but which partly are in different scales from figure to figure. There are shown in:

(2) FIG. 1 a schematic diagram of an extraction appliance, in particular of a coffee machine;

(3) FIG. 2a-2f possibilities of dependencies of a regulating variable correction factor on the measured flow;

(4) FIG. 3a the measured dependency of the flow and of the pressure, in dependence on time, with a normally functioning brewing process;

(5) FIG. 3b the measured dependency of the flow and of the pressure, in dependence on time, in the case of a blockage during the brewing process, according to the state of the art;

(6) FIG. 4 an extraction-side perforation device;

(7) FIG. 5 a cross-sectional representation of a detail of the perforation device of FIG. 4; and

(8) FIG. 6 a different perforation device; and

(9) FIG. 7 a cross-sectional representation of a detail of the perforation device of FIG. 6, said representation being analogous to FIG. 5

DETAILED DESCRIPTION OF THE INVENTION

(10) FIG. 1 shows a schematic diagram of an extraction appliance, in particular of a coffee machine. The water feed includes a water tank 1 and a feed conduit 2 from the water tank to a brewing module 10. The water is delivered by a pump 5 and flows through a water heaterhere drawn as an instantaneous water heaterbefore it flows into the brewing module. A flow sensor 3, which measures the flow of the water through the feed conduit, and, since the feed conduit 2 does not branch, thus also the flow into the brewing module 10, is arranged upstream of the pump.

(11) The arrangement of the flow sensor in front of the pump has the advantage that the flow sensor is not arranged in the region which is under pressure and also not in the hot region. However, an arrangement downstream of the pump or even downstream of the water heater, in the throughflow direction, or in the water heater, is not to be ruled out a priori, in the case of a suitable design of the flow sensor. The integration of the flow sensor into the pump is also an option. At all events, it should be arranged such that the flow, which is measured by it, permits fluid flow into the brewing chamber formed given a closed brewing module and encompassing the capsule 20 to be determined. The fluid quantity flowing per unit of time is indicated as the fluid flow, represented, for example, as a volume or mass per unit time.

(12) The brewing module, as is known per se, comprises an injector 11 for introducing water into a portion capsule 20, as well as a discharge device 12 (or extraction device) for discharging fluid out of the capsule into a pour-out 13.

(13) A control 9 controls the pump 5, and possibly also the water heater. The flow values, which are measured by the flow sensor 3, as well as, as the case may be, the temperature values determined by an optional temperature sensor 8 serve as input variables for the control.

(14) Such a temperature sensor 8, as is drawn, can be arranged in a manner, in which it is in contact with the feed conduit 2, subsequently to the water heater, in the water heater itself or on the water heater. The control can be configured such that it forms a control loop for the temperature, by way of the water heater being activated such that the temperature measured by the temperature sensor 8 always moves in a certain range. The inclusion of other readings, specifically of the measure flow. is also possible for the temperature regulation.

(15) Further input variables can be led to the control 9 and influence this.

(16) The extraction appliance, for example, can have an input module and/or programming module 6, via which a desired fluid quantity as well as, under certain circumstances, also the temperature and possibly also a desired pump power can be influenced.

(17) A further possibility is the provision of a capsule recognition module 15, by way of whichfor example by way of a suitable coding of the inserted portion capsulethe parameters characterising the capsule can be called up, for example information as to whether the capsule comprises finely ground coffee or coffee which in contrast is more coarsely ground.

(18) Moreover, it is also possible for a pump overheating sensor (not represented in the figure) or further sensors or input possibilities to be present.

(19) In embodiments, a manometer is not necessary, in order to influence the pump power, and generally such is also not present at all. One of the advantages of the procedure according to the invention is the fact that one can make do without such a relatively expensive and service-intensive element.

(20) The pump activation can be directly or indirectly dependent on all these measured parameters. However, one preferably envisages the measured fluid flow being used as the sole measured variable, on account of which the control adapts the pump power during the brewing method. All other parameters, inasmuch as they have an influence on the pump activation, either effect a presetting (for example a desired fluid quantity or an on/off of the adaptive pump activation) or, if need be, a termination of the brewing method (for example actively by the user via the input module and/or programming module 6 or by way of a pump overheating protection etc.), but preferably not an adaptive activation of the pump power.

(21) Possibilities, as to how the regulating variable can be dependent on the measured flow are yet sketched in FIGS. 2a to 2f. In each case, a correction factor K is plotted in dependence on the flow F in the figures. It is assumed that the following is valid for the pump power P: P=P.sub.0K, wherein P.sub.0 corresponds to a normal power or maximal power. Another regulating variable (speed, frequency etc.) which influences the power can be set analogously to the power.

(22) According to FIG. 2a, the factor K is reduced from 1 to a value K.sub.0, as soon as the flow falls short of a threshold value F.sub.S (see also FIG. 3b). The factor remains at the value K.sub.0 independently of the further development of the flow, after the reduction has been effected.

(23) Several steps can also be envisaged, in contrast to FIG. 2a, for example the reduction to K.sub.1 on falling short of an upper threshold value, and the reduction to K.sub.2<K.sub.1 on falling short of a lower threshold value.

(24) FIG. 2b shows a variant, according to which the factor K is set back to 1 again if the flow then increases again beyond the threshold value after a reduction of K. A hysteresis can be envisaged, as is represented in FIG. 2b, i.e. the setting back to 1 is not effected until exceeding an upper threshold value F's, in order to prevent a rapid switching to and fro. This embodiment can also be generalised onto several steps.

(25) In the embodiments of FIGS. 2a and 2b, the value K.sub.0 is smaller than 1 and larger than 0 and, for example, can be between 0.3 and 0.8, in particular between 0.4 and 0.7, especially between 0.5 and 0.6.

(26) FIG. 2c shows an example of a dependency on K as a continuous function of F. The value K is 1 above an upper threshold value F.sub.U, with a linear reduction down to a minimal correction factor K.sub.m at a lower threshold value F.sub.L. The value K.sub.m for example can lie between 0.3 and 0.8, in particular between 0.4 and 0.7, especially between 0.5 and 0.6.

(27) The dependency of the factor on the flow as a function, which is composed of several straight lines having different gradients and which is linear in sections and as a whole is continuous, results in the embodiment according to FIG. 2d. FIG. 2e shows the generalisation onto a continuous, non-linear function.

(28) A dependency K(F), with which the gradient is negative in a region (unbroken line to the very right) is drawn in FIG. 2f. According to this variant therefore, it is possible for the pump power to drop again with very large measured flows.

(29) According to a subvariant, one can optionally also envisage the correction factor remaining at 1 even with large flows (dashed line; (1)), at the very beginning of the brewing process, until the capsule is filled with fluid according to experience, whilst it is reduced (unbroken line; (2)) in a later phase of the brewing process at high measured flows.

(30) Analogously, it would also not be completely ruled out for the pump power to increase again at very small measured flows (to the very left in the picture).

(31) In all embodiments, the respective threshold values, in particular F.sub.S, are matched to the respective flow values in normal operation with a brewing without a blockage. In embodiments with steps such as in FIGS. 2a and 2b, the threshold value or the uppermost threshold value, for example, can lie between 50% and 85% of a normal flow (normal flow in the context of the average flow which results after a certain time, after the capsule is filled with water). In embodiments with a continuous course, the uppermost threshold valve F.sub.U for example can lie at a value between 70% and 110% of the normal flow, and a possible lower threshold (FIGS. 2c and 2d) between 0 and maximal 70% of the upper threshold value.

(32) Combinations of the procedural manners according to FIGS. 2a-2f are also conceivable, for example a step-like reduction on falling short of a threshold value, in combination with a linear or non-linear function, etc.