Apparatus and method for detecting an abnormality during the closure of an infusion unit

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a method and a machine for producing beverages by infusing a product in packaged form.

[0002] It is particularly suitable for espresso coffee machines. It can also be used to produce beverages from other materials such as tea. STATE OF THE ART

[0003] Many beverage preparation machines, such as tea or coffee machines, for domestic or professional use, now use packaging, also called capsules or doses, which form a relatively compact set of product to be infused.

[0004] These machines comprise an infusion group comprising two parts, at least one of which is movable relative to the other. A relative separation of these two parts makes it possible to open the infusion group, while a rapprochement of these two parts makes it possible to close the infusion group. This mobility is ensured by an electric motor thus making it possible to selectively open or close the infusion group. The infusion group delimits an internal volume between the two parts. The opening allows an introduction, into said internal volume, of the packaging comprising the product to be infused, such as coffee or tea, preferably ground, or the ejection of a used dose.

[0005] The closure allows the infusion group to be closed around the said dose of product, including its casing, in a watertight manner, before proceeding with an injection of hot water under pressure into the internal volume of the infusion group, to extract, from the product, a drink.

[0006] Before injecting hot water, it is important to ensure that the brewing unit is properly closed to ensure it is watertight. However, it may happen that a pod is not properly inserted, becomes stuck, and an odd error prevents the brewing unit from closing completely.

[0007] To address this problem, documents WO2011147792 or FR2916336 propose machines with generally high reliability. This high reliability results essentially from sequential operation of the machine based on a number of parts and very specific kinematics.

[0008] Still with the aim of addressing this problem, other solutions provide for the use of a position sensor, placed on the motor or on another moving element, such as a transmission, the position of which is indicative of the closure of the infusion group. Thus, document WO2005 / 058111 describes a machine in which the positioning of the capsule is controlled by microswitches.

[0009] Furthermore, it is also known, for example from EP11171021, to use an analysis of the intensity of the control current of the motorization to detect a closing problem, which may be linked to a stuck pod.

[0010] Documents EP2926698 and EP2981838 provide, in a coffee machine, means for measuring an electrical parameter representative of the current absorption of a motor actuating the parts of the brewing chamber, means for comparing with a fixed reference a change in the measured parameter as a function of time during the transfer of the assembly from the open position to the closed position and means for providing activation means with an input resulting from the comparison of the change in said measured parameter with the set reference.

[0011] However, despite these existing solutions, in practice, we still often see the machine jamming and preventing the beverage from being prepared. The jammed packaging must then be removed manually by the user, or even by a service dedicated to machine maintenance.

[0012] There is therefore a need to make machines for preparing drinks from packaging containing a product to be infused even more reliable, by reducing the risks of packaging getting stuck in the machine. This is an objective of the present invention. SUMMARY OF THE INVENTION

[0013] The invention relates to a method for detecting an anomaly in the closure of an infusion group of a beverage preparation machine such as a tea or coffee machine, preferably of the espresso type, the infusion group comprising an infusion chamber delimited by two parts having mobility relative to each other, at least one of the two parts being moved by an actuator comprising an electric motor, said two parts being configured to, during a phase of closing the infusion group, move closer to each other to grip a package. The method comprises the following steps, advantageously executed by at least one data processing device comprising for example a computer or a microprocessor: determination of a nominal characteristic of the intensity of a supply current of the motorization as a function of time, measurement of the intensity of the supply current of the motorization, at least during a closing phase of the infusion group, comparison of the measured intensity with said nominal characteristic, and detection of a closing anomaly when a measurement of the intensity deviates from the nominal characteristic by more than one threshold.

[0014] The nominal characteristic is determined from at least one measurement phase carried out on said beverage preparation machine during at least one closing phase which has taken place correctly, the nominal characteristic being updated from a characteristic of the intensity of the supply current of the motorization as a function of time determined during a closing phase which has taken place correctly.

[0015] The industrial manufacture of brewing units, typically by molding and machining, induces unavoidable dimensional variations. Such variations are also found in packaging, which is typically made by superimposing several layers, for example of paper or by stamping aluminum sheets. Similarly, each manufacture of the electric motor presents variabilities in these characteristics and particularly in its current consumption. In the context of the development of the present invention, it was discovered, by analyzing the cases of failure of the prior art solutions, that the dimensional variations and electrical characteristics could be significant.However, with current methods for detecting the closing resistance of the brewing unit, it is not possible to determine whether the variations in this resistance are attributable to variations in the mechanism or to an abnormality in the closing of the unit, and in particular to packaging stuck in the mechanism, because this does not necessarily lead to significant variations in the closing resistance of the brewing unit. Also, if a significant tolerance is taken around the nominal operating threshold in order to take these dimensional variations into account, and even if the intensity of the power supply current to the motorization presents significant differences between correct closing and a closing anomaly, these differences can be masked by this significant variability in the characteristics specific to each brewing unit design.Thus, the methods for detecting a closure defect of the prior art may be unable to correctly detect a jammed pod, because they are unable to distinguish between variations in the intrinsic resistance of the brewing unit and those due to a jammed packaging. The preparation machine may then become blocked and require maintenance by an operator or the user, resulting in at least temporary unavailability of the machine.

[0016] Conversely, if too low a tolerance is taken around the nominal operating threshold, too great a dimensional or electrical variation can lead to exceeding an anomaly detection threshold. The consequence is that the machine will then wrongly conclude that there is a closing anomaly.

[0017] This will cause the beverage preparation machine to go into error mode and will then be, at least temporarily, unavailable.

[0018] The invention provides that the detection is adapted to each brewing group. The step of determining a nominal intensity characteristic, the step of measuring the intensity of the supply current and the comparison step are carried out on the same brewing group. Thus, the thresholds for identifying a closing anomaly are determined by the brewing group actually used in the machine in question. This makes it possible to clearly discern the portion of resistance due to the mechanism of the brewing group of the machine and thus to have identification thresholds very close to a nominal characteristic observed during a correctly carried out closing phase in this group. The nominal intensity characteristic does not come from a modeling or an empirical determination carried out from another brewing group, and which is applied to a set of groups of the same type.

[0019] The level of detection precision makes it possible to eradicate cases of non-detection which led to the launch of the infusion cycle with the infusion chamber incompletely closed, resulting in leaks and projection of water (and coffee) into and sometimes out of the machine.

[0020] This also makes it possible to detect very quickly that a variation in the intensity of the motor supply current is actually due to an anomaly. It is then possible, as soon as this anomaly begins, to stop the closing phase. It follows that the packaging is less likely to remain stuck after the two moving parts have been moved away from each other. The risk of packaging breaking is also reduced or even eliminated.

[0021] These advantages are considerable since, with prior art devices, the detection of jamming often occurs very late after the start of the jamming, the packaging tears and the product to be infused it contains disperses in the machine. A cleaning operation, often long and tedious, is then necessary. The downtime of the machine is increased, which can lead to a significant loss of income when the machine is used in a commercial establishment such as a café, a hotel or a restaurant.

[0022] In addition, the proposed method significantly increases the safety of the machine. Indeed, if the jamming of the two moving parts is due to the presence of a user's finger, the latter is detected very quickly. The two moving chambers stop moving towards each other immediately, thus not aggravating the finger pinch.

[0023] Another considerable advantage of the present invention is that the detection of the closure anomaly evolves over time. It therefore makes it possible to take into account the evolution of the dimensions and resistance characteristics of an infusion group, for example under the effect of mechanical wear, or under the effect of expansion of the parts forming the group.

[0024] Furthermore, it allows for the replacement of one or more parts making up the brewing unit, or even a complete replacement of the brewing unit.

[0025] Optionally, the invention may comprise at least any one of the following features which may be taken separately or in combination: According to one example, the actuator comprising an electric motor comprises at least one of: an electric cylinder, an electrically motorized knee lever, a rack device comprising a pinion driven by the electric motor and a rack meshing with the pinion, a set of gears cooperating with one or both moving chambers. As indicated above, according to the invention, the nominal characteristic is updated from a characteristic of the intensity of the supply current of the motor, preferably as a function of time. This characteristic of the intensity of the supply current of the motor, from which the nominal characteristic is updated, is determined during a closing phase that has taken place correctly.According to one example, the updating of the nominal characteristic is carried out by averaging the intensity characteristics of the supply current of the motorization as a function of time corresponding to the most recent correctly executed closing phases included in a sliding window of at most p correctly executed closing phases, with p being an integer, preferably between 2 and 100. According to one example, p is between 5 and 20 and preferably p is equal to 10.

[0026] According to one example, a first nominal characteristic is obtained by determining n characteristics of the intensity of the supply current of the motorization as a function of time, corresponding to n correctly executed closing phases, and by averaging these n characteristics, with n integer, preferably between 1 and 10.

[0027] For example, n is equal to 2.

[0028] According to one example, a resetting step of determining a new first nominal characteristic and replacing the previously determined first nominal characteristic with said new first nominal characteristic.

[0029] Thus, the reset step places the process in an initial state, that is to say in the state in which it was before determining the first nominal characteristic.

[0030] This replacement is carried out in a memory associated with the machine. According to one example, the threshold is defined by a first template, called the min template, substantially parallel to the nominal characteristic by lower value and by a second template, called the max template, substantially parallel to the nominal characteristic by higher value. According to one example, the min template has a value substantially equal to - X% of the value of the nominal characteristic, with preferably X > 0 and X less than or equal to 20, preferably X less than or equal to 10, preferably X less than or equal to 5.

[0031] Thus, at each instant, the intensity of the minimum template is both: less than the intensity of the nominal characteristic and at the same time greater than or equal to the intensity of the nominal characteristic - 10%, and preferably - 5%. According to one example, the max gauge has a value substantially equal to + Y% of the value of the nominal characteristic, with preferably Y > 0 and less than or equal to 20, preferably X less than or equal to 10, preferably X less than or equal to 5.

[0032] Thus, at each instant, the intensity of the maximum template is both: greater than the intensity of the nominal characteristic and at the same time less than or equal to the intensity of the nominal characteristic + 10%, and preferably + 5%. According to one example, the execution of at least one of the following steps is carried out when a closing anomaly is detected: emission of a visual alarm signal to the attention of a user of the machine, emission of an audible alarm signal to the attention of a user of the machine, sending of an electronic message to a maintenance center, interruption of the closing phase, triggering of a phase of separation of the two parts (3,4), interruption of a circulation of water in a circuit of the machine, for example by stopping a water circulation pump in a circuit of the machine.

[0033] According to another embodiment, the invention relates to a device for detecting an anomaly in the closing of an infusion group of a beverage preparation machine such as a tea or coffee machine, preferably of the espresso type, the infusion group comprising an infusion chamber delimited by two parts having mobility relative to each other, at least one of the two parts being moved by an actuator comprising an electric motor, said two parts being configured to, during a phase of closing the infusion group, move closer to each other to grip a package, the device being configured to carry out the following steps: determination of a nominal characteristic of the intensity of a supply current of the motorization as a function of time, measurement of the intensity of the supply current of the motorization, at least during a closing phase of the infusion group, comparison of the measured intensity with said nominal characteristic, and detection of a closing anomaly when a measurement of the intensity deviates from the nominal characteristic by more than one threshold.

[0034] The nominal characteristic is determined from at least one measurement phase carried out on said beverage preparation machine during at least one correctly completed closing phase.

[0035] Preferably, the device comprises a computer such as a microprocessor configured to perform the above steps.

[0036] According to one embodiment, the nominal characteristic is determined from at least one measurement phase carried out on said beverage preparation machine during at least one closing phase having taken place correctly and during which a package is clamped between the two parts of the infusion chamber. Thus, the nominal characteristic is determined in the presence of a package.

[0037] According to another embodiment, the invention relates to a beverage preparation machine comprising at least: at least one infusion group comprising an infusion chamber delimited by two parts having mobility relative to each other, an actuator comprising an electric motor, the actuator being configured to: o during a closing phase of the infusion group: bring the two parts closer to each other to enclose a package, o during an opening phase of the infusion group: move the two parts away from each other to allow a package to enter or exit the infusion chamber, a device as described previously.

[0038] According to one embodiment, one of the parts of the infusion chamber is fixed relative to a frame of the machine. The other part is movable, in translation or in rotation, relative to the frame of the machine.

[0039] According to another embodiment, the two parts of the infusion chamber are movable, in translation or in rotation, relative to the frame of the machine.

[0040] The machine is configured so that, when the detection device detects a closing anomaly, the actuator stops the two parts from coming together and / or moves the two parts away from each other.

[0041] According to another embodiment, the invention relates to a use of a packaging comprising a product to be infused, for: implement a beverage preparation machine comprising packaging between the two parts, or implement the method as described above. BRIEF DESCRIPTION OF THE FIGURES

[0042] Other characteristics, details and advantages of the invention will emerge more clearly from the detailed description given below for information purposes in relation to drawings in which: there Figure 1a illustrates a first embodiment of an infusion group, the Figure 1b illustrates a second embodiment of an infusion group, the figure 2 illustrates a nominal characteristic and the comparison of an intensity with this nominal characteristic.

[0043] The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily to the scale of practical applications. DETAILED DESCRIPTION OF THE INVENTION

[0044] In the context of the present invention, packaging 2 containing a product to be infused, for example ground coffee, can be used. The product to be infused is enclosed by an envelope in a closed interior volume of the packaging. The interior volume is configured to be able to be crossed by a liquid such as water during infusion. It is for example delimited by an envelope formed of filter sheets, for example made of paper, fiber or plastic, or by a wall made of a waterproof material (for example aluminum or plastic) but made filterable by perforation.

[0045] When the envelope is formed of filter sheets, the latter may for example comprise or be formed of paper, fibers or plastic.

[0046] When the envelope is formed of a wall made of a waterproof material, the latter may for example comprise or be formed of aluminum or plastic.

[0047] The packaging comprises a perimeter 21. According to a non-limiting example, the closed volume 2 containing the product to be infused has axial symmetry and the perimeter 21 is included in a plane perpendicular to the axis of symmetry.

[0048] In a non-limiting manner, the volume 2 containing the product to be infused is constituted by the assembly of layers joined by their peripheries at the level of a support frame defining a peripheral perimeter 21.

[0049] The present invention can be used with various types of packaging. In particular, it does not imply that the perimeter of the packaging is rigid. It applies to packaging having a flexible outer envelope of the dose type or a rigid outer envelope of the capsule type and more generally to any type of single-use packaging of a product to be infused. It also applies to packaging whose outer envelope is capable of disappearing at least in part during infusion, by dissolution for example. It also applies to packaging formed from a product to be infused aggregated by a binder and / or by the application of pressure. Such packaging formed from an aggregate of a product to be infused such as coffee can be formed outside the machine or be formed by a dedicated module of the machine.

[0050] Embodiments of the present invention will now be described with reference to Figures 1a , 1b And2 .

[0051] The Figure 1a, presents an embodiment of at least one part of a beverage preparation machine. A fixed body 1 accommodates a motor 6 and an infusion group 100. The infusion group 100 comprises two complementary parts 3, 4 in order to delimit an internal volume or infusion chamber 5 in which a packaging 2 can be accommodated. The two parts 3, 4 are movable relative to each other so as to selectively open the infusion group 100 or close it. The open position, shown in dotted lines, allows the introduction of a new pod 2 or the ejection of an old pod, used after infusion. A slide 9 allows the pod 2 to be guided during its introduction. The closed position, shown in solid lines, makes it possible to maintain a packaging 2 in said internal volume, advantageously sealed, while an injector injects hot water under pressure in order to carry out the infusion and the production of a beverage.

[0052] The mobility of the two parts 3, 4 can be according to any movement. In the example illustrated in Figure 1a , the movement is rotary. Each part 3, 4 is articulated in rotation, relative to the fixed body 1 by a shaft 8. Part 3 comprises an external gear 7 capable of meshing with a complementary gear of part 4. The motorization 6, here rotary, comprises a pinion capable of meshing with one of the two previous gears 7, for example the gear of part 4, as illustrated.

[0053] As illustrated in Figure 1b , the two moving parts can be mutually moved away and brought together by a translational movement, preferably a linear translation.

[0054] On the example of the Figure 1b , we find the infusion chamber 5 comprising the chambers 3, 4. In this example, the chamber 3 is fixed relative to the body 1 of the infusion group 100. The body 1 is integral with a frame of the machine.

[0055] The chamber 4 is movable in translation relative to the body 1 of the infusion group 100. The actuator 61, comprising an electric motor 6, controls the movement of the movable part 4 of the infusion chamber 5.

[0056] This actuator may include, for example, an electric cylinder, a rack and pinion system, a worm screw, etc.

[0057] The beverage preparation machine also comprises a water tank 20 in fluid communication with a pump 30 via a conduit 21. The pump 30 makes it possible to supply water to an inlet of a boiler 40. Alternatively, the boiler 40 is supplied by a pressurized water distribution network. An outlet of the boiler 40 is in fluid communication with the infusion chamber 5. Typically, a conduit 42 connects the outlet of the boiler 40 to one of part 3 or part 4. If the hot water supplied by the boiler 40 reaches the infusion chamber 5 via the movable part 4, the conduit 42 is preferably flexible to accompany the movement of this movable part 4.

[0058] When the two parts 3, 4 are separated, a package 2 can then enter the infusion chamber 5. During the closing phase, the parts 3, 4 move closer together until they enclose the package 2. If the closing phase takes place correctly, the package 2 is enclosed in the infusion chamber 5. The latter can, for example, form a sealed envelope around the package 2. The machine then triggers the supply of hot water to the infusion chamber 5 from the boiler 40. The hot water infuses the product contained in the package 2 and escapes from the infusion chamber 5 through conduits such as the conduit 31 leading to a container, typically a cup 15. At the end of the infusion, the two parts 3, 4 move away from each other. The infusion chamber 5 opens, allowing the package to escape, for example by gravity.

[0059] In the example illustrated in Figure 1b, the closing phase does not take place correctly and the packaging is stuck between parts 3 and 4.

[0060] The invention proposes an effective solution for detecting an anomaly in the closing of the infusion group 100.

[0061] This method comprises the following steps. During a first step, a nominal characteristic 11 is determined, representing the intensity of the supply current of the motorization 6 as a function of time. This nominal characteristic 11 covers at least the closing phase of the brewing group 100. Equipped with this nominal characteristic 11, typically recorded in a memory of the brewing group 5 more generally of the machine, the method measures the intensity 14 of the supply current of the motorization 6. This is carried out by the method at least during the closing of the brewing group 100. The intensity is typically measured regularly during the closing phase. Each measurement 14 of the intensity is then compared with the nominal characteristic 11.

[0062] An anomaly is detected when a measurement of the intensity of the supply current flowing in the motorization 6 deviates too much, more or less, from the nominal characteristic 11, that is to say from the intensity value indicated by the nominal characteristic 11, at the corresponding instant in the closing phase. This distance can be indicated by means of at least one threshold 12, 13.

[0063] According to an advantageous characteristic of the invention, the nominal characteristic 11 is determined by learning on the same beverage preparation machine where the anomaly detection method is installed. The nominal characteristic 11 is obtained from at least one measurement phase carried out on said machine, during at least one correctly unrolled closing phase. A correctly unrolled closing phase corresponds to a closing phase during which the packaging is not jammed by the two parts 3, 4 of the infusion chamber 5. The result of a correctly unrolled closing phase is that the packaging 2 is sandwiched between the two parts 3, 4 and positioned in an infusion position. The infusion cycle can continue. Typically, hot water, preferably under pressure from a boiler 40, enters the infusion chamber 5 and infuses the product contained in the packaging 2.

[0064] Thus, the nominal characteristic 11 provides a reference for the correct behavior, when the closure of the infusion group occurs without anomaly, to which can be compared, in real time, the behavior of the infusion group 100 during a new closure monitored by the anomaly detection method. If the intensity measurement 14, carried out in real time, during a closure, “follows” the nominal characteristic 11, fairly closely, it can be considered that the monitored closure occurs without anomaly.

[0065] The advantage of establishing the nominal characteristic 11 on the very machine where the anomaly detection method is implemented is that this nominal characteristic 11 is personalized in that it intrinsically integrates all the particularities of this machine, such as dimensional or other variations and thus makes it possible to overcome them.

[0066] A characteristic of the intensity of the supply current flowing in the motor 6 as a function of time is a curve showing the intensity on the ordinate and the time on the abscissa. An example of such a characteristic is shown in figure 2 with nominal characteristic 11. Such characteristic is determined by any means.

[0067] According to one embodiment, the intensity is regularly measured and recorded as a function of time, preferably during a closing phase. It is still possible to carry out several observations / readings and to apply filtering, for example averaging between the different observed characteristics.

[0068] Such customization is particularly advantageous in that, by applying the solutions of the state of the art, taking into account dimensional variations leads to increasing the threshold used to compare an acceptable current intensity with a nominal characteristic. This results, in the prior art, in a widened tolerance which can allow an anomaly to go undetected.

[0069] On the contrary, the characteristic of the invention, in that it personalizes the nominal characteristic 11, makes it possible to obtain a nominal characteristic 11 closer to the actual behavior, and therefore more adapted to the monitored machine. This advantageously makes it possible to reduce the acceptance threshold and thus to reduce the tolerance, allowing for a much more discriminating comparison, without introducing false detections. Furthermore, this makes it possible to detect an anomaly much earlier in time. The clamping force exerted on the dose or on a finger trapped between the 2 parts 3, 4 is then much lower at the moment when the closing phase is interrupted.

[0070] This is illustrated by the figure 2. The nominal characteristic 11 is shown in the center. If a single nominal characteristic 11 is used, common to all machines, it is necessary to take into account the dimensional dispersion inevitably linked to mass production. This leads, by applying the solutions of the state of the art, to min 15 and max 16 gauges arranged relatively far from the nominal characteristic 11. This distance leads to accepting, due to the extended tolerance, a measurement 14 of the intensity, even though it is deviant and indicative of a closing anomaly.

[0071] On the contrary, if, according to the invention, the nominal characteristic 11 is determined for the monitored machine, the dimensional dispersion is avoided and the min 12 and max 13 gauges can be arranged much closer to the nominal characteristic 11 and used to compare with a measured intensity 14, without the risk of introducing false detections. Thus, a deviation 17 of the measured intensity 14, indicative of a closing anomaly, can be detected as soon as it exceeds one of the gauges 12, 13. This same anomaly would not have been detected with the thresholds of the min 15 and max 16 gauges.

[0072] The sensitivity of a closing anomaly being much lower than the sensitivity to dimensional dispersion, the characteristic of customizing a nominal characteristic 11 to a machine, provided by the invention, proves to be essential.

[0073] In order to further improve this customization, the nominal characteristic 11 is updated, based on a characteristic of the intensity of the supply current of the motorization 6 as a function of the time determined during a correctly executed closing phase. In order to be indicative of a nominal / correct operation, to which it is possible to refer, it is appropriate to consider only closing phases carried out correctly, without anomaly. This updating is advantageously carried out on a regular basis, throughout the life of the machine. This advantageously makes it possible to take into account, by integrating it into the nominal characteristic 11, dimensional or other variations that may occur, for example due to the aging or wear of the machine and its mechanical, electrical and / or electronic components.Thus, nominal characteristic 11 remains indicative of the condition of the machine and its correct operation in closing, throughout the life cycle.

[0074] In this sense, the proposed method does not take into account a tolerance interval in relation to the same nominal characteristic determined for a set of machines.

[0075] When the machine is first used, a first nominal characteristic 11 must be determined. Unlike the prior art, which implements a standard characteristic, typically determined on another machine, such a possibility is not open for a machine according to the invention. This first nominal characteristic 11 is obtained by performing one or more operating cycles comprising at least one closing phase. During this / these closings, the intensity is measured as a function of time in order to determine one or more intensity characteristics of the supply current of the motorization 6 as a function of time. This is carried out n times. It is verified that each closing phase takes place correctly, without anomaly. Otherwise, the characteristic obtained is rejected. n is an integer, preferably between 1 and 10, and even more preferably equal to 2.For n at least equal to 2, the different characteristics retained are advantageously averaged, in order to make the first resulting nominal characteristic 11 more robust.

[0076] Once this nominal characteristic 11, first or initial, has been obtained and recorded, the method can detect an anomaly during subsequent closing phases and can be fully implemented. It is thus also possible to automatically differentiate between a correctly executed closure and an anomaly.

[0077] Any correctly executed closing phase can be used to determine a new intensity-time characteristic and use it to update the nominal characteristic 11. Alternatively, it is still possible to update only at a lower frequency.

[0078] According to a possible embodiment, the updating can be carried out by means of a sliding window of at most p such intensity-time characteristics. For this, for any correctly executed closing phase, after determination of the first nominal characteristic 11, it is possible to determine a characteristic. For each new such characteristic, a new nominal characteristic 11 can be recalculated by averaging the first nominal characteristic 11 with the following determined characteristics. We speak of a window of width p in that we average at most p characteristics, the nominal characteristic 11 being included. The window is sliding in that, when we have more than p characteristics, only the most recent p are kept to calculate the average. The averaging range p is an integer, preferably between 2 and 100. Satisfactory results have been obtained with p equal to 10.

[0079] Averaging performs filtering, improving stability by limiting the effects of an atypical characteristic. Regularly introducing new recent characteristics into the set of averaged characteristics ensures that the nominal characteristic 11 is updated and thus matches the actual behavior of the machine, even if the latter changes.

[0080] A new characteristic can be determined and considered for averaging for any correctly performed closing phase. Alternatively, a new nominal characteristic calculation 11 can be carried out regularly every x operating cycles or every y hours of operation or machine life.

[0081] When an anomaly is detected, a maintenance process can be triggered, for example including a return to the factory.

[0082] A special case occurs when the machine is significantly modified. This is the case, for example, following maintenance, replacing an important part, including the brewing group 100 or one of its components. The behavior of the machine may be significantly modified. Also, in this case, it is appropriate to carry out a new determination of a first or initial nominal characteristic 11. Also, to inform the device / process thereof, the latter advantageously comprises a reset device. This reset device, usable by the user or the maintenance technician, makes it possible to inform the device / process of said modification.It allows a reset step to be launched which has the effect of returning the device / process to an initial state, or similar, in which a new nominal characteristic 11 must be determined, starting from zero, like the first initial nominal characteristic 11 described above.

[0083] For example, the reset device is activated by pressing a dedicated button located on the brewing group 100 or more generally on the machine. This button is for example accessible to an operator manually or by a tool. In a complementary or alternative manner, this button can be activated automatically by the introduction of a brewing group into the machine or by the removal of a brewing group from the machine. Preferably, access to this function is restricted to reserve it for the maintenance technician. Typically, a reset can be initiated either via a dedicated button located in the machine, or by a sequence of buttons which gives special access privileges to the technician, or via an access menu reserved for the technician for machines having a screen interface with menus.

[0084] As illustrated in the figure 2, the threshold 12, 13, used for the comparison step, is materialized by a min template 12 substantially parallel to the nominal characteristic 11 by lower value and by a max template 13 substantially parallel to the nominal characteristic 11 by higher value. The comparison then verifies that the measured intensity 14 remains between the min template 12 and the max template 13. As soon as the measured intensity 14 goes outside these limits, as in 17, an anomaly is detected.

[0085] According to another characteristic, the min template 12 has a value substantially equal to - X% of the value of the nominal characteristic 11. In a complementary or alternative manner, the max template 13 has a value substantially equal to + X% of the value of the nominal characteristic 11. As detailed above, the invention makes it possible to determine a very reliable nominal characteristic 11. This makes it possible to consider a tolerance around this nominal characteristic 11 and therefore a very low threshold. This threshold X is preferably less than or equal to 10, preferably 5.

[0086] Thus, at each instant, the intensity of the template min 12 is both: less than the intensity of the nominal characteristic and at the same time greater than or equal to the intensity of the nominal characteristic 11 minus 10%, and preferably minus 5%.

[0087] Similarly, at each instant, the intensity of the max template 13 is both: greater than the intensity of the nominal characteristic 11 and at the same time less than or equal to the intensity of the nominal characteristic 11 plus 10%, and preferably plus 5%.

[0088] This advantageously provides a strong discriminating effect of the process, even though a closing anomaly, for example due to stuck packaging 2, may only create a limited deviation.

[0089] In the constraint, the prior art, to take into account dimensional dispersions, must consider a threshold at least equal to + / - 20%. Such a value greatly reduces its discriminating effect, to the point of being unable to detect an anomaly of the stuck pod type.

[0090] In the embodiment, it is provided that when the detection device detects a closing anomaly, the machine performs at least one of the following actions: emission of a visual alarm signal to a user, emission of an audible alarm signal, sending of a message to a maintenance center, interruption of the closing phase, triggering of a phase of separation of the two parts 3,4, interruption of water circulation in a circuit of the machine, for example by stopping a water circulation pump in a circuit of the machine.

[0091] The invention also relates to a device implementing such a method. In view of the preceding description, it is clear that by carrying out continuous self-learning of its own intensity characteristic during a "normal real" cycle and by systematically carrying out a comparison of each closing phase with it, the proposed machine makes it possible to detect an intensity variation with a very reduced margin of error since it is free from all the parasitic variations due to the manufacture of the multiple elements.

[0092] Thus, the proposed machine makes it possible to reduce to a minimum the margin of error necessary around "normal real" operation and makes it possible to measure and detect small variations in intensity characteristic of a stuck dose pinch.

[0093] In view of the foregoing description, it is clear that the invention provides a simple and robust solution for improving the reliability of beverage preparation machines by identifying a closing anomaly more precisely. Furthermore, the invention makes it possible to considerably increase the safety of these machines by detecting an operating anomaly much earlier than is possible with the solutions of the prior art.

[0094] Although a preferred embodiment of the invention is described herein, it should be understood that the invention is not limited to this embodiment, and that variations may be made within the scope of the following claims.

Claims

1. Method for detecting an anomaly in the closure of an infusion unit of a beverage preparation machine, the infusion unit (100) including an infusion chamber (5) which is delimited by two parts (3, 4) that can be moved relative to one another, at least one of the two parts (3, 4) being moved by an actuator (61) comprising an electric motor (6), said two parts (3, 4) being configured so that, during a closing phase of the infusion unit (100), they move towards one another to surround a package (2), the method comprising the following steps: - determining a nominal characteristic (11) of the intensity of a supply current to the motor (6) as a function of time, - measuring the intensity of the supply current intensity to the motor (6), at least during a closing phase of the infusion unit (100), - comparing the measured intensity with said nominal characteristic (11), and detecting an anomaly in the closure when a measurement of the intensity deviates from the nominal characteristic (11) by more than one threshold (12, 13), characterised in that the nominal characteristic (11) is determined from at least one measurement phase carried out on said beverage preparation machine during at least one closing phase which has been performed correctly, the nominal characteristic (11) being updated again from a characteristic of the intensity of the supply current to the motor (6) as a function of the time determined during a closing phase which has been performed correctly.

2. Method according to the preceding claim, wherein the nominal characteristic (11) is updated again using characteristics of the intensity of the supply current to the motor (6) as a function of the time corresponding to the most recent correctly performed closing phases included in a sliding window of at most p correctly performed closing phases, with p being an integer, preferably between 2 and 100.

3. Method according to the preceding claim, wherein p is between 5 and 20 and preferably p is equal to 10.

4. Method according to any one of the preceding claims, wherein a first nominal characteristic (11) is obtained by determining n characteristics of the intensity of the supply current to the motor (6) as a function of time, corresponding to n correctly performed closing phases, and by averaging these n characteristics, with n being an integer, preferably between 1 and 10.

5. Method according to the preceding claim, wherein n is equal to 2.

6. Method according to any one of the two claims, comprising a resetting step consisting of determining a new first nominal characteristic (11) and replacing the first previously determined nominal characteristic with said new first nominal characteristic.

7. Method according to any one of the preceding claims, wherein the threshold (12, 13) is defined by a first gauge (12), referred to as the min gauge, substantially parallel to the nominal characteristic (11) by lower value and by a second gauge (13), referred to as the max gauge, substantially parallel to the nominal characteristic (11) by higher value.

8. Method according to the preceding claim, wherein the min gauge (12) has a value substantially equal to - X% of the value of the nominal characteristic (11), with preferably X >0 and X less than or equal to 20, preferably X less than or equal to 10, preferably X less than or equal to 5.

9. Method according to any one of the two preceding claims, wherein the max gauge (13) has a value substantially equal to + Y% of the nominal characteristic value (11), with preferably Y > 0 and less than or equal to 20, preferably X less than or equal to 10, preferably X less than or equal to 5.

10. Method according to any one of the preceding claims, comprising performing at least one of the following steps when an anomaly of the closure is detected: - emitting a visual alarm signal for the attention of a user of the machine, - emitting an audible alarm signal for the attention of a user of the machine, - sending an electronic message to a maintenance centre, - interrupting the closing phase, - triggering a phase in which the two parts (3, 4) are moved apart, - interrupting water circulation in a circuit of the machine, for example by stopping a water circulation pump (30) in a circuit of the machine.

11. Device for detecting an anomaly in the closure of an infusion unit of a beverage preparation machine, the infusion unit (100) including an infusion chamber (5) which is delimited by two parts (3, 4) that can be moved relative to one another, at least one of the two parts (3, 4) being moved by an actuator (61) comprising an electric motor (6), said two parts (3, 4) being configured so that, during a closing phase of the infusion unit (100), they move towards one another to surround a package (2), the device being configured to perform the following steps: - determining a nominal characteristic (11) of the intensity of the the supply current of the motor (6) as a function of time, - measuring the intensity of the supply current of the motor (6), at least during a closing phase of the infusion unit (100), - comparing the measured intensity with said nominal characteristic (11), and detecting an anomaly in the closure when a measurement of the intensity deviates from the nominal characteristic (11) by more than one threshold (12, 13), characterised in that the nominal characteristic (11) is determined from at least one measurement phase carried out on said beverage preparation machine during at least one correctly performed closing phase, the nominal characteristic (11) being updated again from a characteristic of the intensity of the motor supply current (6) as a function of the time determined during a closing phase that has been performed correctly.

12. Beverage preparation machine comprising at least: - at least one infusion unit (100) including an infusion chamber (5) which is delimited by two parts (3, 4) that can be moved relative to one another, - an actuator (61) comprising an electric motor (6), the actuator being configured: o during a closing phase of the infusion unit (100): to bring the two parts (3, 4) closer together to surround a package (2), o during an opening phase of the infusion unit (100): to move the two parts (3, 4) away from each other to allow a package (2) to enter or exit the infusion chamber (5), - a device according to the preceding claim.

13. Machine according to the preceding claim, configured such that, when the detection device detects an anomaly in the closure, the actuator (61) stops the two parts (3, 4) from moving closer together and / or moves the two parts (3, 4) away from one another.

14. Use of a package (2) comprising a product to be infused, for: - operating a beverage preparation machine according to claim 12 comprising a package (2) between the two parts (3, 4), or - implementing the method according to any one of claims 1 to 10.