A method for automatically adjusting the duration of a kneading operation carried out by a kneading device, and a kneading device implementing such a method.

Abstract

The invention relates to a method for automatically adjusting the kneading time of dough, said kneading being carried out by a kneading device comprising a bowl for receiving ingredients and a kneading element configured to mix the ingredients inside the bowl. The method (100) comprises the following steps: - rotating (101) the kneading element, the rotational speed of the kneading element being maintained constant throughout the kneading time; - determining (102) representative values ​​of the torque exerted in the kneading element so as to establish a curve of the evolution of the torque during kneading; - detecting (107) a decrease or stagnation of the torque exerted in the kneading element for a predetermined period; - stopping (109) the rotation of the kneading element when a decrease or stagnation of the torque is detected. Figure for the abstract: Fig. 3

Description

Title of the invention: Method for automatically adapting the duration of a kneading operation implemented by a kneading device and kneading device implementing such a method TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a kneading method used in the preparation of a food dough. The method can in particular be used for the preparation of flour-based doughs and is particularly suitable for the preparation of a dough intended for the manufacture of bread.

[0002] It also relates to a kneading device, more commonly called a kneader, configured to implement such a kneading method. STATE OF THE ART

[0003] Kneading dough, such as that used to make bread, has an effect on the molecular chains of the dough. By kneading the dough, a mechanical force is applied and allows the molecular chains present in the flour to form and align.

[0004] Proper kneading promotes the formation of long, elastic molecular chains. These chains contribute to the structure and elasticity of bread by trapping carbon dioxide produced by yeast, which allows the dough to rise and develop an airy texture.

[0005] Insufficient kneading can lead to poor molecular chain formation, making the dough less elastic and less able to retain carbon dioxide. The bread may then be dense and poorly risen.

[0006] On the other hand, excessive kneading, also called overkneading, can cause molecular chains to break, reducing their ability to form a solid structure. This can result in bread that lacks elasticity and has a hard or crumbly texture.

[0007] It is therefore crucial to find a balance in kneading in order to obtain the best formation of molecular chains, thus promoting the ideal texture and rising of the bread.

[0008] Kneading is generally carried out by a kneader essentially comprising a bowl in which ingredients are placed and at least one kneading member rotated inside the bowl to knead the ingredients and thus form a dough.

[0009] There are kneaders comprising a force sensor configured to measure the torque exerted in the kneading member. These kneaders are based on the observation that the formation of these molecular chains leads to an increase in kneading resistance. In other words, the dough becomes firmer as it is kneaded.

[0010] In particular, kneaders are known which are configured to detect when the torque exerted in the kneading member reaches a predefined torque threshold corresponding to an ideal degree of kneading.

[0011] This solution is not, however, entirely satisfactory. In particular, the degree of kneading is, in certain cases, not always ideal. This is explained by the fact that the consistency of the dough can vary greatly depending on certain parameters, including the quantity of flour, the temperature, the humidity level, the type of ingredients and their quantity.

[0012] It is therefore difficult to propose a solution providing an ideal degree of kneading each time without requiring manual adjustment of the torque to be achieved. Statement of the invention

[0013] The present invention aims to remedy all or part of the drawbacks of the state of the art cited above.

[0014] To this end, the invention relates, according to a first aspect, to a method for automatically adapting a kneading time for a food dough, said kneading being implemented by a kneading device comprising a tank intended to receive ingredients and a kneading member configured to mix the ingredients inside the tank. The method comprises the following steps: - rotating the kneading member, the rotation speed of the kneading member being kept constant throughout the kneading; - determination of representative values ​​of the torque exerted in the kneading member so as to establish a curve of the evolution of the torque during kneading; - detection of a drop or stagnation of the torque exerted in the kneading member for a predetermined duration; - stopping the rotation of the kneading member when a drop or stagnation of the torque is detected.

[0015] Based essentially, or even solely, on measurements of the torque exerted in the kneading member, the method according to the invention makes it possible to obtain a regular degree of kneading without having to measure parameters such as the recipe, the quantity of ingredients, the temperature or the humidity level.

[0016] The operator only has to introduce the ingredients into the bowl and start the mixer. He can thus take care of other operations in parallel without worrying about kneading the dough.

[0017] Some preferred but non-limiting aspects of this kneading method are as follows.

[0018] The step of detecting a drop or stagnation in torque may include the following step: - comparison of at least three consecutive representative values ​​of the torque, namely a first value, a last value and at least one intermediate value, the predetermined duration extending between an instant when the first value is determined and an instant when the last value is determined, the stopping of the rotation of the kneading member being implemented if the at least one intermediate value and the last value are less than or equal to the first value.

[0019] The step of determining representative values ​​of the torque may include the following step: - measurement of the torque exerted in the kneading member, the torque being measured periodically throughout the duration of the kneading, according to a predetermined sampling period.

[0020] The step of determining representative values ​​of the torque may further comprise the following steps: - determination of a smoothing period which is at least twice the sampling period so that the smoothing period includes at least two measurements of the torque exerted in the kneading member; - for each smoothing period, calculation of an average of the torque measurements included in the smoothing period.

[0021] The method may comprise the following step: - comparison (106) of the values ​​representative of the torque with a torque threshold, the torque threshold being representative of a minimum degree of kneading, the stopping of the rotation of the kneading member being implemented if the at least one intermediate value and the last value are less than or equal to the first value and if one of the values ​​representative of the torque reaches the torque threshold.

[0022] The torque threshold can be determined by selecting one of the first representative values ​​of the torque determined during the step of determining representative values ​​of the torque, and by adding thereto a predefined torque increase value which is characteristic of an increase in torque during kneading.

[0023] The invention also relates, according to a second aspect, to a kneading device comprising: - a tank suitable for receiving dough, - a kneading member arranged at least partially inside the tank, - a means of driving the kneading member in rotation, - a force sensor configured to measure the torque exerted in the pe- braiding, and - a processing unit configured for implementing the method according to the first aspect of the invention.

[0024] The invention also relates, according to a third aspect, to a computer program comprising instructions for executing the steps of the method according to the first aspect of the invention. BRIEF DESCRIPTION OF THE FIGURES

[0025] Other advantages, aims and particular characteristics of the present invention will emerge from the following non-limiting description of at least one particular embodiment of the devices and methods which are the subject of the present invention, with reference to the appended drawings, in which: • [Fig. 1] schematically represents a kneader according to one embodiment of the invention; • [Fig.2] illustrates in graphic form two examples of implementation of a kneading method in accordance with one embodiment of the invention; and • [Fig.3] represents in the form of a block diagram the method according to one embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] [Fig.l] schematically illustrates a kneader 1 according to one embodiment of the invention. The kneader 1 essentially comprises a frame 2 and a bowl 3 arranged on the frame 2.

[0027] The tank 3 defines an internal space suitable for receiving ingredients.

[0028] The tank 3 has an upper opening allowing access to the internal space.

[0029] The kneader 1 further comprises a kneading member 4 configured to mix the ingredients received in the tank 3.

[0030] The kneading member 4 is arranged in the internal space of the tank 3 when it is in a so-called kneading position. Indeed, the kneading member 4 can be movable between the kneading position and a rest position in which it is arranged outside the tank 3 in order to allow in particular easy access to the tank 3 via its upper opening.

[0031] The kneader 1 comprises means 5 for driving the kneading member 4 in rotation and a force sensor 6 configured to measure the torque exerted in the kneading member 4. The drive means 5 comprise, for example, an electric motor. The force sensor 6 is, for example, integrated into a power variator of the electric motor.

[0032] The kneader 1 also comprises a processing unit 7 configured to determine a predefined degree of kneading from the data measured by the force sensor 6.

[0033] The processing unit 7 is configured to implement a kneading method according to the invention, described with reference to Figures 2 and 3.

[0034] [Fig.2] is a graph showing the evolution of the torque exerted by the kneading member over time according to a first kneading, represented by curve A, and a second kneading, represented by curve B.

[0035] The difference in torque evolution between these two kneading operations is explained in particular by a different type of flour. Generally speaking, the increase in the quantity of ingredients is linked to the increase in the measured torque, but has little influence on the duration of kneading. On the other hand, the temperature has a strong influence on the duration of kneading.

[0036] The detection of an ideal degree of kneading known in the state of the art consists of determining the torque exerted in the kneading member and comparing it with a maximum torque threshold, determined from tests carried out under specific conditions.

[0037] Since the consistency of the dough may vary if one of these conditions is changed, comparing the torque exerted in the kneading member with the same torque threshold may result in the detection of different degrees of kneading.

[0038] The present invention was developed by the applicant on the basis of the observation that a dough has an ideal degree of kneading when all the molecular chains are formed, which amounts to saying that the ideal degree of kneading occurs when the torque exerted in the kneading member reaches its maximum.

[0039] The detection of such a degree of kneading by the solution of the state of the art is then only possible if the maximum torque threshold corresponds exactly to the maximum torque exerted in the kneading member, which is particularly unlikely given the variability of the consistency of the dough.

[0040] In practice, the solution of the state of the art leads to the detection of an insufficient degree of kneading according to the observation made by the applicant. This is in fact explained by the risk of never detecting the ideal degree of kneading by determining a threshold that is too high.

[0041] It is then proposed in the invention to take advantage of this observation to detect an ideal degree of kneading in a reliable and reproducible manner, in particular when parameters such as temperature, humidity level, type of ingredients and their quantity vary.

[0042] More specifically, it is proposed to detect a trend in the torque rather than an absolute value as described in the prior art solutions.

[0043] As can be seen in [Fig.2], an ideal degree of kneading was determined by the method according to the invention for the first kneading and the second kneading. This degree of pe- braiding is indicated respectively by points FA and FB.

[0044] It should be noted that the torque exerted in the kneading member at points FA and Fb is not the same and these points correspond to a different kneading duration. This is explained by the fact that the method is based essentially, or even solely, on the trend of the torque exerted in the kneading member.

[0045] In this example, the first kneading and the second kneading were deliberately prolonged after the detection of the ideal degree of kneading in order to highlight the fact that the torque exerted in the kneading member no longer increases after this detection. This means that all the molecular chains have been formed.

[0046] [Fig. 3] is a block diagram illustrating in detail the kneading method 100 according to the invention. This method makes it possible to knead the dough to a predefined degree of kneading which makes it possible to guarantee a satisfactory and consistent quality of the products made from this dough, in particular bread.

[0047] The kneading method 100 comprises a step 101 of driving the kneading member in rotation. The ingredients to be mixed to obtain a dough are introduced into the tank beforehand or during the rotation of the kneading member.

[0048] The kneading member is rotated at a predetermined constant speed. Rotating the kneading member 4 at a constant speed makes it easier to observe the torque exerted in the kneading member. Indeed, the torque exerted in the kneading member thus corresponds to the torque necessary to maintain the constant speed. The variations in torque thus make it possible to precisely observe the consistency of the dough.

[0049] The rotation speed of the kneading member can be adjusted manually, but cannot be changed during kneading.

[0050] The kneader may comprise an interface electrically connected to the rotation drive means and configured to send a rotation drive signal in response to an action by the operator.

[0051] The method 100 comprises a step 102 of determining values ​​representative of the torque exerted in the kneading member so as to establish a curve of the evolution of the torque during kneading.

[0052] The determination step 102 comprises a step 103 of measuring the torque exerted in the kneading member, via the force sensor. The torque is measured periodically throughout the duration of the kneading, according to a predetermined sampling period. The sampling period is chosen so as to guarantee sufficient precision. For example, the sampling period may be equal to 2 seconds.

[0053] Significant fluctuations may, however, appear during the various measurements, which may lead to errors in the interpretation of the evolution of the torque.

[0054] To limit these fluctuations, it is possible to increase the sampling period, but the precision is then also reduced.

[0055] The determination step 102 further comprises a step 104 of determining a smoothing period which is at least twice the sampling period so that the smoothing period comprises at least two measurements of the torque and, for each smoothing period, a step 105 of calculating an average of the measurements of the torque included in the smoothing period.

[0056] The calculation of the average is carried out by the processing unit.

[0057] The mixer may further comprise a memory unit configured to store the measurements. Averages can also be stored in the mixer's memory unit.

[0058] The sampling period and the smoothing period are chosen so as to obtain smoothing of the curve without causing a delay in detection. For example, the smoothing period may be equal to 15 seconds.

[0059] Thus, the averaging calculation makes it possible to limit fluctuations while maintaining the precision of the torque measurements. This thus facilitates the detection of the ideal degree of kneading while guaranteeing sufficient reliability.

[0060] It should be noted that such a step was applied for the kneadings of [Fig.2], so that the points of each of the curves A and B correspond to the average of the torque measurements carried out during a smoothing period.

[0061] It should also be noted that these steps 104, 105 are optional and that the following steps of the method can be implemented directly with the torque measurements carried out by the force sensor during step 103.

[0062] The method comprises a step 106 of comparing the average with a torque threshold, determined so as to guarantee a sufficient degree of kneading. In other words, this comparison makes it possible to avoid insufficient kneading of the dough.

[0063] The threshold is determined by adding to one of the first averages calculated during step 105, a predefined torque increase value. “First calculated averages” means a predefined number of averages calculated consecutively from the first average calculated after the kneading member has been rotated in step 101.

[0064] The torque increase value is characteristic of an increase in the typical torque when kneading a dough, regardless of parameters such as the recipe, the quantity of ingredients, the temperature or the humidity level. The torque increase value is typically between 1 Nm and 100 Nm, and more precisely between 30 Nm and 50 Nm

[0065] By determining the torque threshold from one of the data measured by the sensor effort, it is possible to automatically adapt its value by freeing itself from the measurement of parameters such as the recipe, the quantity of ingredients, the temperature or even the humidity level.

[0066] The torque threshold thus makes it possible to ensure, whatever the temperature and humidity conditions, the recipe or the quantities of ingredients, that a predefined degree of kneading is reached. This thus makes it possible to avoid, for example in the event of false detection of a drop or stagnation of the torque, stopping the kneading when the degree of kneading is insufficient.

[0067] In practice, the smallest average value among a predefined number of the first calculated averages is chosen to determine the torque threshold.

[0068] In [Fig.2], the torque threshold of each of curves A and B is indicated respectively tively by the CA and CB references. In this example, each threshold was determined by selecting the smallest of the first three calculated averages. For curve A, this is the first calculated average. For curve B, this is the third calculated average.

[0069] The method comprises a step 107 of detecting a drop or stagnation of the torque for a predetermined duration.

[0070] The predetermined duration extends between two averages, namely a first average and a last average, not necessarily consecutive. A decline or stagnation is detected when, during the predetermined duration, no average following the first average exceeds the first average.

[0071] In particular, the detection step comprises a step 108 of comparing at least three consecutive averages, namely a first average, a last average and at least one intermediate average.

[0072] The predetermined duration extends between the time when the first average is calculated and the time when the last average is calculated.

[0073] A drop or stagnation during the predetermined duration is then detected when the value of the at least one intermediate average and the last average does not exceed the value of the first average.

[0074] The choice of at least three consecutive averages makes it possible to detect the ideal degree of kneading relatively quickly while avoiding the detection of parasitic fluctuations. Preferably, four consecutive averages are compared for the detection of stagnation or torque drop.

[0075] The method finally comprises a step 109 of stopping the rotation of the kneading member when the average has reached the torque threshold and when a drop or stagnation of the torque is detected.

[0076] By satisfying these two conditions, we ensure that all the molecular chains have been formed and therefore that the degree of kneading is ideal.

[0077] If a drop or stagnation of the torque is detected but the torque has not reached the torque threshold, the kneading member is prevented from stopping rotation. In other words, as long as the torque is below the torque threshold, the kneading member is prevented from stopping rotation. However, the stop can be triggered manually by an operator, even if these conditions are not met.

[0078] The stopping of the rotation here corresponds to the end of the kneading, the method thus makes it possible to automatically adapt the duration of the kneading.

[0079] Based essentially, or even solely, on measurements of the torque exerted in the kneading member, the method makes it possible to obtain a regular degree of kneading without having to measure parameters such as the recipe, the quantity of ingredients, the temperature or the humidity level.

[0080] The operator only has to introduce the ingredients into the bowl and start the mixer. He can thus take care of other operations in parallel without worrying about kneading the dough.

Claims

Claims

1. Method for automatically adapting a kneading time of a food dough, said kneading being implemented by a kneading device (1) comprising a bowl (3) intended to receive ingredients and a kneading member (4) configured to mix the ingredients inside the bowl (3), said method (100) comprising the following steps: - rotating (101) the kneading member (4), the rotation speed of the kneading member (4) being kept constant throughout the kneading time; - determining (102) values ​​representative of the torque exerted in the kneading member (4) so ​​as to establish a curve of the evolution of the torque during the kneading; - detecting (107) a drop or stagnation of the torque exerted in the kneading member (4) for a predetermined time; - stopping (109) the rotation of the kneading member when a drop or stagnation of the torque is detected.

2. Method according to claim 1, characterized in that the step of detecting (107) a drop or stagnation of the torque comprises the following step: - comparison (108) of at least three consecutive values ​​representative of the torque, namely a first value, a last value and at least one intermediate value, the predetermined duration extending between an instant when the first value is determined and an instant when the last value is determined, the stopping (109) of the rotation of the kneading member (4) being implemented if the at least one intermediate value and the last value are less than or equal to the first value.

3. Method according to one of claims 1 or 2, characterized in that the step (102) of determining values ​​representative of the torque comprises the following step: - measurement (103) of the torque exerted in the kneading member (4), the torque being measured periodically throughout the duration of the kneading, according to a predetermined sampling period.

4. Method according to claim 3, characterized in that the step (102) of determining representative values ​​further comprises the following steps - determining (104) a smoothing period which is at least two times greater than the sampling period so that the smoothing period includes at least two measurements of the torque exerted in the kneading member (4); - for each smoothing period, calculation (105) of an average of the torque measurements included in the smoothing period.

5. Method according to any one of claims 1 to 4, characterized in that it comprises the following step: - comparison (106) of the values ​​representative of the torque with a torque threshold (CA and CB), the torque threshold (CA and CB) being representative of a minimum degree of kneading, the stopping (109) of the rotation of the kneading member (4) being implemented if the at least one intermediate value and the last value are less than or equal to the first value and if one of the values ​​representative of the torque reaches the torque threshold.

6. Method according to claim 5, characterized in that the torque threshold (CA and CB) is determined by selecting one of the first values ​​representative of the torque determined during the step (102) of determining values ​​representative of the torque, and by adding thereto a predefined torque increase value which is characteristic of an increase in torque during kneading.

7. Kneading device comprising: - a tank (3) adapted to receive a dough, - a kneading member (4) arranged at least partially inside the tank (3), - means (5) for driving the kneading member (4) in rotation, - a force sensor (6) configured to measure the torque exerted in the kneading member (4), and - a processing unit (7) configured to implement the method according to any one of claims 1 to 6.

8. Computer program comprising instructions for executing the steps of the method according to one of claims 1 to 6, when said program is loaded and executed by a processor.

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