WO2024110072A1 - Device and method for determining a bubble, method for removing a bubble, and kitchen appliance - Google Patents

Abstract

The invention relates to a device for determining whether a bubble is present in a food being processed by a rotatingly driven working means, comprising a power determining device for determining the power of the drive with which the working means is driven and comprising an analysis device for determining whether a bubble is present, wherein the analysis device detects a bubble on the basis of the output of the power determining device.

Description

Device and method for determining a bubble, method for removing a bubble and kitchen appliance

Technical area

The invention relates to a device for determining whether a bubble is present in a foodstuff processed by a rotating working medium. It also relates to a kitchen appliance with such a device. The invention also relates to a method for determining whether a bubble is present in a foodstuff processed by a rotating working medium and a method for removing such a bubble.

Technical background

Kitchen appliances such as stand mixers are often used to process food in domestic and catering environments. In such appliances, a working tool, which can, for example, be in the form of rotating blades, is arranged to rotate within a container and can be driven by a motor. By rotating this working tool, the food filled into the container is chopped and mixed.

During the processing in such a stand mixer, an air bubble can form around the rotating tool. This can be due, for example, to the food being pushed outwards due to centrifugal force, causing air to collect around the tool. This effect is disadvantageous in that the tool, which is now freely rotating, can no longer process the food, or can hardly do so, as it is not in contact with it or is only in a much smaller area. This problem is particularly relevant for foods with a high viscosity such as spreads, baby food, frozen fruit, nut butters such as peanut butter, etc. The rotating working medium pushes the food to the side and due to the high viscosity of the food, it no longer flows back to the working medium but remains in a position radially outside the working medium.

In order to be able to further process the food in such a state, there are several options that a user can use.

Firstly, a user can insert a mashing device, which can be used to press the foodstuffs towards the working medium by hand while the appliance is in operation. Such mashing devices often look like a large spoon, a cylindrical rod or similar. In order to press the foodstuffs towards the working medium using such a mashing device, in many cases the mashing device is introduced through an opening in a lid of the container in which the foodstuffs are located. Such a method can be used while the motor is running, so that the kitchen appliance does not have to be stopped.

On the other hand, the rotation speed of the motor can be reduced manually by setting a lower speed. After a short time, the original speed can then be set again. At a lower speed, the centrifugal forces that occur are lower, which often leads to food that has stuck to flow back to the working medium and also to the air bubble being able to rise upwards through the food so that it is removed from the working medium. Since this causes the food to flow back to the working medium flow, it is possible to continue the processing.

It is also possible to switch off the appliance, remove the lid from the container and either mix the food to be processed manually or press it into the working medium using a tamper. This way the air bubble disappears and the food can cover the working medium again without an air bubble. Then the lid is placed on the container and the appliance is switched on again.

It is possible to repeat each of these steps several times and this may be necessary depending on the food to be processed. However, a disadvantage of this is that such a process is inconvenient for a user and therefore an automated process would be advantageous.

Furthermore, it would also be advantageous for a user to be able to automatically detect an air bubble. According to the state of the art, it depends on the user's experience and powers of observation whether he recognizes that an air bubble is present. If the user does not recognize the air bubble as such and does not take countermeasures, this leads to an unsatisfactory processing result. It would therefore be advantageous if it did not depend on the user whether an air bubble is detected.

Description of the invention

The present invention has been made in view of the aforementioned disadvantages and aims to at least partially remedy or alleviate them.

The invention is defined by the independent claims. Preferred embodiments are defined in the respective dependent claims. According to the invention, there is a device for determining whether a bubble is present in a foodstuff processed by a rotating working medium. In this case, it can be determined whether a bubble is present which interacts with the working medium and in particular surrounds it.

Depending on the embodiment, the device has a device for determining operating parameters of the drive. Such operating parameters include the power and/or the rotational speed of the drive. The inventors have found that a bubble can be detected using these parameters. This device determines at least the current power consumed and/or rotational speed of the drive by which the working medium is driven. Such a power determining device determines the current power of the drive, which drives the working medium, by simultaneously measuring the applied voltage, the current currently flowing and taking into account the power factor (cos (phi)) of the electric motor.

Furthermore, an evaluation device is provided. This determines whether a bubble is present. The evaluation device determines this presence based at least on the output of the determination device. Thus, it is determined based on the operating parameter(s) of the drive whether a bubble is present. The inventors noticed that it is possible to determine whether a bubble is present based on the temporal progression of the drive's power. A bubble is typically accompanied by a significantly reduced rotational resistance of the working medium, which is noticeable in that the required power drops abruptly. Accordingly, it can be determined based on the progression of the power curve whether a bubble is present. The bubble can also manifest itself through an abrupt increase in rotation speed.

Preferably, the evaluation device only determines that a bubble is present if the power drops by more than a certain proportion of the initial value of the power within a predetermined period of time. The predetermined amount can be an amount defined as a percentage of the maximum instantaneous power of the drive during the processing operation during which the presence of a bubble is to be determined. In particular, the predetermined amount can be 30%, more preferably 50%, possibly even 90% of this maximum value. These features enable an easy decision as to whether a bubble is present, resulting in a robust method with few falsely detected bubbles.

In this context, it is further preferred that the device has a rotational speed determination device for determining the rotational speed or speed of the working medium. Furthermore, an evaluation device is also provided here. The rotational speed will generally increase when a bubble is present, since such a bubble exerts less resistance on the working medium. Preferably, it is only determined that a bubble is present when the rotational speed increases by a predetermined amount, which is particularly preferably at least 30%, more preferably at least 50% of the rotational speed before the increase in the rotational speed.

It is also preferred that the power determining device and the speed determining device are present and provided with a common evaluation device. In this case, the selected device only determines that a bubble is present if the rotational speed increases together with the drop in power. Therefore, a drop in power combined with an increase in rotational speed is a more reliable indication of the presence of a bubble than a drop in power by a predetermined amount alone. In this respect, a corresponding device is more reliable. However, the function can also be demonstrated if only one of the two determining devices is present.

It is further preferred that a speed control device is present which can be provided with a speed target value via a user interface, which corresponds to the setpoint of the control device in normal operation. During use of the device, the control device constantly measures the actual speed of the drive and accordingly adjusts the voltage output to the drive so that the actual speed is kept as constant as possible at the speed setpoint.

The above-mentioned power determination device, rotation speed determination device and speed control device are preferably present together in the device, but the individual elements can also be present in other combinations, resulting in slightly different behaviors and processes in bubble detection:

Variant 1 : Cruise control device,

Power determination device and rotation speed determination device are available.

The user sets a speed level or a program via a control device, which internally corresponds to a target rotation speed. In normal cases (i.e. if no bubble is to be removed) this is identical to the target rotation speed of the speed control device. Since in this case the speed control device controls the rotation speed of the Drive keeps the motor at a constant speed regardless of the load, in this configuration no increase in speed can be detected in the event of a bubble. Therefore, in a controlled system the speed cannot be used to detect bubbles. Instead, only the power determination device can be used for this, as described above. As a special case, it should be mentioned that in exceptional cases the target speed cannot be reached despite the speed control device because the motor does not have the power required for it. In this case the speed increases to the preset target speed when a bubble occurs. However, as this is a special case that only occurs under certain conditions, this increase in speed can optionally only be monitored in addition to that described above. This case will not be considered further in the further descriptions.

Variant 2: Power determination device and rotational speed determination device are present, but no speed control device.

Here, the speed level or program set by the user corresponds internally to a target voltage to be output to the motor. Normally, i.e. when no bubble is to be removed, this target voltage corresponds to the actual output voltage, i.e. the electrical voltage delivered to the drive. Depending on the characteristics of the drive and the existing load, a certain drive speed results for a certain output voltage. Here, a bubble (or the associated reduction in load) therefore leads to a simultaneous increase in speed and a reduction in the power consumed. The evaluation device can therefore use both parameters to detect bubbles, so that the highest level of reliability can be achieved with this method. Variant 3: Only power determination device is available.

Here too, the speed level or program set by the user corresponds internally to a target voltage to be output to the motor. In the normal case, i.e. when no bubble is to be removed, this target voltage corresponds to the actual output voltage, i.e. the electrical voltage delivered to the drive. Depending on the characteristics of the drive and the existing load, a certain speed of the drive results for a certain output voltage. Since the actual speed is not recorded, a bubble (or the associated reduction in load) leads to a reduction in the power consumed, which is detected by the evaluation device.

Variant 4: Only rotation speed determination device is available.

Here too, the speed level or program set by the user corresponds internally to a target voltage to be output to the motor. In the normal case, i.e. when no bubble is to be removed, this target voltage corresponds to the actual output voltage, i.e. the electrical voltage delivered to the drive. Depending on the characteristics of the drive and the existing load, a certain speed of the drive results for a certain output voltage. A bubble (or the associated reduction in load) leads to an increase in speed, which is detected by the evaluation device.

Instead of the previously mentioned adjustment of the voltage output to the motor to achieve a speed change or control, other mechanisms for speed change can also be used. For example, For certain types of motors (such as brushless DC motors), the speed can be adjusted by varying the frequency output to the motor. This is technically equivalent to changing the voltage. For the sake of simplicity, we will therefore only refer to adjusting the voltage below, which is not to be understood as limiting, but also includes varying the frequency.

There are various means for determining the rotational speed that can be used as a rotational speed determining device. For example, there is the possibility of coupling a Hall effect sensor with a magnet or magnetic ring. With such a device, the rotational speed can be measured by the Hall effect sensor together with the magnet. Every time the magnet is near the sensor, the signal output by the sensor changes from on to off or from off to on. The time between these changes of state can be measured and based on this the rotational speed can be determined.

It is also possible to use a combination of a coil and a magnet/magnetic ring. As the magnet moves past the coil, it induces a voltage in the coil. Due to a periodic rotation of the magnet, a periodic sine wave can be induced, where the frequency of the signal is the reciprocal of the rotation speed. The induced voltage can be output to a digital signal via an ADC (analog to digital converter) or can be converted to a digital signal via a Schmitt trigger.

Furthermore, rotational speed can be measured without sensors if the drive is a brushless DC motor. The current can be measured at one of the three windings of such a drive, which during rotation is not supplied with power. This allows the position of the drive to be determined and the rotational speed can be detected by changing the frequency of the supplied voltage.

It is also possible to determine the rotational speed using an optical method. Such optical rotational speed detection uses an optical detection system in which the emitting device and a receiving device arranged opposite one another operate with a light beam. An interruption of the light beam serves as a change of state on the basis of which the rotational speed can be calculated. In this context, there are various ways of implementing this. For example, it is possible for the emitting device and the receiving device to be on opposite sides of a disk provided with light blocking devices, the disk being coupled to the drive. The signal interruptions of the light are detected and the rotational speed is calculated on the basis of them.

Alternatively, there are retroreflective sensors in which the emitting device and receiving device are arranged in the same housing and next to each other. The light is reflected by a mirror or another type of reflection device that is coupled to the drive. The individual light pulses of the reflected light are recorded and the rotational speed is calculated on the basis of them. It is also possible for a marking to be arranged on a rotating part coupled to the drive, which diffuses the light back to a receiving device, so that the pulses are counted and the rotational speed is calculated. It is also possible to measure the rotational speed based on induction, using the principle that the magnetic flux changes as a result of a sensor. A simple magnetic rotor with teeth, coupled to the drive, rotates and changes the size of the gap between the rotor and the sensor, generating a high or low voltage signal. Based on this signal, the rotational speed can be determined.

Power can be determined in various ways. For example, current can be measured. The output of such a sensor is then an analogue signal which is proportional to the current flowing in a cable. The signal can of course also be digital. There are also direct and indirect ways of measuring this current. For a direct method, the current flows through an integrated sensor circuit. An indirect method is used when the sensor measures the current flowing through a nearby cable without itself being located in the cable. A resistor can also be inserted into the cable through which current flows and the voltage drop across this resistor measured. If the resistance value of this resistor is known exactly and, ideally, is as low as possible, the current flowing through this resistor can then be determined using Ohm's law.

It is particularly preferred that the predetermined time period is in the range of 0.05 to 3 seconds, preferably 0.1 to 2 seconds. This means that the increase in rotational speed or the decrease in power must occur comparatively quickly, so that, for example, a long-term reduction in power due to the lower resistance exerted by chopped food does not lead to a bubble being falsely detected. At the same time, the upper limits of the ranges are sufficiently large that the time scales in which such a bubble can typically form are covered.

The above-mentioned ranges for power loss, speed increase and duration can only be understood as realistic example values, as these are heavily dependent on the performance and shape of the kitchen appliance, the processing tools available and the food to be expected (e.g. varies regionally). Therefore, these values must be determined individually for the exact design and target market of an appliance and cannot be given as a general rule.

It is further preferred that an output device is provided which indicates that a bubble is present. This could, for example, be in the form of a light source, such as an LED, which is provided to inform a user of the presence of a bubble. It would also be possible to output a corresponding indication on a display device such as a screen. An acoustic signal could also be emitted. Other types of signals are conceivable, in particular signals which wirelessly inform another device (for example a mobile phone or tablet) that a bubble is present. Such an output device can inform a user that a bubble is present so that he can take steps to remove it. It is also conceivable to have only an output device for displaying a bubble on the device, without the device attempting to remove the bubble on its own. In this way, only the detection is displayed, but the removal of the bubble is left entirely to the user.

According to the invention, there is also provided a kitchen appliance for processing foodstuffs by means of a rotatingly driven working means, which comprises a device as previously has been described. Such a kitchen appliance has the advantage that it allows easier removal of bubbles. Such a kitchen appliance can be a stand mixer. However, many other types of kitchen appliances are conceivable, for example food processors, hand blenders, whisks, kneading machines, hand mixers, etc.

In this context, it is preferred that the kitchen appliance is designed to

• to temporarily reduce the target rotational speed of the working equipment from the set target value if it is determined that a bubble is present, and then to return the target rotational speed to the target value (applicable to variant 1 - with speed control) or.

• to temporarily reduce the output voltage supplied to the drive from the set target voltage when it is detected that a bubble is present and then return the output voltage to the target voltage (applicable to variants 2-4 - without speed control).

The reduction in the target rotational speed is preferably reduced by at least 20%, more preferably at least 50% of the target rotational speed, even more preferably the target rotational speed is reduced to the minimum possible rotational speed of the system. Here, the target rotational speed is the rotational speed that is output to the drive by the control of the device and which the drive should therefore achieve. In normal operation, i.e. when no bubbles are to be removed, this Nominal speed of rotation is identical to the target speed set by the user. However, during the bubble removal process the nominal speed of rotation may be temporarily lower than this target speed. In principle it is also possible to stop the equipment, i.e. to switch off the drive briefly, but the drive should then be restarted within a sufficiently short time (e.g. 1 second as specified in UL982 Ed. 8 §27. 13) to prevent a user from reaching into the equipment under the mistaken assumption that the kitchen appliance is switched off. A longer time may be possible provided the appliance detects whether the lid is closed. In this case there is no danger for a user of reaching into a running appliance.

After the target rotation speed has been reduced, it is increased again to the target value. Accordingly, the target rotation speed is only reduced temporarily. By reducing the target rotation speed, the centrifugal force acting on the food to be processed is temporarily reduced. If the food has a sufficiently low viscosity, this causes the bubble to collapse, allowing the bubble to be eliminated. If such a process is carried out automatically when a bubble is detected, this increases the processing efficiency of the kitchen appliance and the user-friendliness, since such bubbles which disrupt processing can be automatically eliminated.

In this context, it is preferred that the kitchen appliance is designed to reduce the target rotational speed several times and then increase it when the evaluation device determines that a bubble is present. By such a multiple reduction and increase of the target rotational speed, such a bubble can be removed more easily. In this context, it is further preferred that the kitchen appliance outputs a signal that a bubble is still present if, after a predetermined number of reductions and increases in the target rotational speed, it is determined that a bubble is still present. Such a determination that the bubble is still present can, for example, be expressed in the fact that the power of the drive is still a certain percentage (for example at least 10%) lower than the power before it was determined that a bubble is present. This can make the user aware that the bubble is still present despite the automated method for removing the bubble. The user can then remove this bubble, for example by means of a stamping device or other suitable means.

The procedure described above can be applied analogously to devices without speed control (variants 2-4). In this case, when a bubble occurs, the target rotation speed is not adjusted, but the output voltage is adjusted analogously.

In embodiments without a power detection device, the continued presence of a bubble can also be determined by evaluating the speed of the working medium. For example, if after increasing the output voltage back to the target voltage, the rotational speed is still a certain percentage (for example at least 20%) below the rotational speed before a bubble was detected.

Furthermore, a method for determining whether a bubble is present in a food processed by a rotating working means is claimed, as defined in claim 10. Regarding the features and advantages of this method and the corresponding preferred method claims, we refer to the relevant Device features which have been discussed above. The same applies to the method according to the invention for removing a bubble from a foodstuff to be processed using a rotating working medium.

Short description of the drawings

Figure 1 shows schematically a kitchen appliance according to the invention.

Figure 2 is a diagram for explaining the detection of a bubble according to a first embodiment.

Figure 3 shows a method for detecting a bubble according to a second embodiment.

Figure 4 illustrates a procedure for removing a bubble which was successful .

Figure 5 shows an unsuccessful procedure for removing a bubble.

Figure 6 shows a flow chart of a method according to the invention for determining a bubble and for removing a bubble according to variant 1.

Figure 7 shows a flow chart of a method according to the invention for determining a bubble and for removing a bubble according to variant 2.

Figure 8 shows a flow chart of a method according to the invention for determining a bubble and for removing a bubble according to variant 3.

Figure 9 shows a flow chart of a method according to the invention for determining a bubble and for removing a bubble according to variant 4. Detailed description of the drawings

Figure 1 shows schematically a stand mixer 100 as a

Example of a kitchen appliance according to the invention.

In the stand mixer 100, a container 1 is arranged on a housing 5. The container 1 contains foodstuffs 2 which are to be processed by a working medium 4 in the form of a rotating blade. The working medium 4 is driven by a drive 6 which is arranged in the housing 5. However, due to the rotation of the working medium 4, an air bubble 3 has formed around the working medium 4, which prevents the working medium 4 from processing the foodstuffs 2. The stand mixer 100 is supplied with power and thus driven via a power supply 9. At the same time, the rotational speed (referred to as "speed" in the drawings) of the drive 6 and/or the current flowing to the drive 6 are measured by corresponding devices 7. This makes it possible to determine how high the current power of the drive 6 is. Via a control unit 8, which contains an evaluation device for the measured rotational speed and/or power, the incoming mains voltage of the power supply 9 can be reduced by means of corresponding setting means 10 in order to supply the drive 5 with a desired output voltage or with a voltage that is required to achieve a certain target speed. The control means 8 is also designed to determine the presence of the bubble 3 and to take steps to eliminate it, as will be discussed further.

The basic idea in determining whether a bubble 3 is present will become clear by reference to Figures 2 and 3. Figure 2 shows the temporal progression of the rotational speed of the drive as well as the power of the drive 6. Figure 2 is an example of an embodiment according to variant 2, which records both rotational speed and power, but has no speed control device. As shown there, the power drops from a maximum value, which corresponds to the power when processing food, to approximately the idle power within approximately 1 second, while at the same time the rotational speed when processing food increases from a lower value to a second, higher value, which corresponds approximately to the idle speed. This increase also occurs essentially at the same time as the drop in power, i.e. in this case over approximately 1 second. This drop in power can be caused by the formation of a bubble, which facilitates the rotation of the working medium 4. Therefore, if the control device 8 detects a corresponding behavior of the rotational speed and the power of the drive 6, it will determine that a bubble 3 is present which has arisen within the time range marked as the bubble detection range. The inventors have found that such a drop in power or increase in rotational speed typically occurs on a time scale of 0.1-2 seconds. The precise values of this time scale depend on the volume of the products to be processed and also the structure of the food to be processed, as well as the design (i.e. the exact design of the container 1 and the working means 4, as well as the drive 6) of the device. In this respect, the temporal size of the bubble detection range depends, among other things, on the ingredients to be processed. It should also be noted that here the rotational speed was averaged over time in order to compensate for short-term fluctuations due to the inhomogeneity of the food to be processed. Figure 3 shows a method which can be used with a constantly regulated rotational speed of the working medium 4 (corresponds to variant 1; rotational speed and power are recorded and a speed control device is present). In this case too, a bubble occurs in the area referred to as the bubble detection area. In this case, however, the rotational speed of the drive 6 is regulated or, for other reasons, essentially constant. However, here too the power drops from a maximum value, which corresponds to the power when processing food, to a power which approximately corresponds to the idle power, since the resistance from the food is greatly reduced due to the formation of a bubble which surrounds the working medium 4. In this case too, the control device 8 will determine that a bubble is present.

For variants 3 & 4 not described, this procedure applies analogously, except that there either only the power curve or only the speed curve is monitored.

The control device 8 is further designed to drive the drive 6 in such a way that a bubble 4 detected in this way can be removed. Corresponding procedures are shown in Figures 4 and 5.

In Figure 4, a successful bubble removal cycle is explained using a device of variant 2 (rotational speed and power are recorded, but no speed control is present). Before time tO, no bubble is present. The rotational speed is at the initial value nO and the power at the initial value PO. At time tO, a bubble forms. The rotational speed increases to a value nl, approximately the idle speed, the power drops to a value PI, approximately the idle power. In During the detection cycle 1 in the range from t0 to t1 (which is, for example, 1 s), it is determined that the power decreases rapidly, while over the same period the rotational speed of the drive means 4 increases, which is why the control device 8 assumes that a bubble 4 is present. Accordingly, starting from time t1, the control device 8 reduces the output voltage, which leads to a reduction in the rotational speed, and keeps this at the low output voltage for a certain reduction cycle 1 (t1-t3) of, for example, approximately 2.4 to 4.1 seconds. A typical length of the reduction cycle is in the range of 0.5-15 seconds, which makes it possible to carry out short reduction pulses which are repeated often, or longer reduction pulses which are repeated less quickly. This reduction in rotational speed reduces the centrifugal force exerted on the food 2, allowing the bubble 4 to collapse.

In the present example, the bubble collapses at t2, which increases the load and thus leads to a further drop in the rotational speed. At the same time, the power consumed increases. After the reduction cycle 1 has ended at time t3, the control device 8 increases the output voltage back to the initial value. A check is then made at time t4 as to whether, at the end of this bubble removal process, both the power and the rotational speed have returned to the values nO and PO that existed before the appearance of the bubble 4, which is the case in the present example. Since the bubble 4 has been successfully removed, no further steps are necessary and processing therefore continues as normal. The control device 8 will, however, continue to check the rotational speed and power consumption in order to detect the appearance of further air bubbles. The typical duration of such a cycle is approximately 4-20 s. Figure 5 shows an unsuccessful bubble removal cycle, also an example of an embodiment according to variant 2. Here too, at time tO there is a sharp drop in power from PO to PI combined with an increase in rotational speed from nO to nl. As a result, the control device carries out a reduction cycle between t1 and t3, as described for Figure 4, and then increases the output voltage back to the target voltage. However, since the bubble has not collapsed in this example, the rotational speed and power do not return to the initial values nO and PO, but to nl and PI, which approximately correspond to the idle speed and power. Accordingly, two further reduction cycles are carried out in which the output voltage and thus the rotational speed are reduced and then increased again, which in the present example does not cause the bubble to collapse either. The control device 8 will determine after a predetermined number of cycles (in this case three cycles) at time t7 that these automated steps have not resulted in the bubble 4 being removed and will alert the user that an air bubble 4 is present which he should remove manually.

The method according to the invention of variant 1 is shown in detail in Figure 6. After a step S100 of starting the method, the rotational speed of the drive means 4 is set and monitored by a control device 8 (step S102). The speed is only set and monitored here in order to reduce it to the reduced speed or to increase it to the target speed. Since the speed is constantly regulated, it is not used for bubble detection. At the same time (step S104), the power of the drive 6 is monitored. The next step is to check (step S106) whether the processing of the food has ended. This is the case, for example, if the user stops the processing manually or the program has expired. If this is the case (yes in step S106), the method ends (step S120).

However, if the processing of the food has not yet ended (No in step S106), as already described previously with reference to Figures 2 and 3, it is determined whether a bubble is present (step S108). If no such bubble is present (No in step S108), the rotational speed continues to be monitored and adjusted if necessary (step S102). However, if a bubble is present (Yes in step S108), the target speed of the drive 4 is reduced (step S110) in order to lead to a collapse of the air bubble 3, as described, for example, with reference to Figure 4. After a certain previously set period of time, the target speed is then increased to the target speed (step S112) in order to return to the desired processing method. It is then checked (step S114) whether the performance is within a normal range. Normal ranges are understood here to mean that the performance corresponds to those values within measurement tolerances and normal variations occurring during processing that existed before the change in performance that led to the determination that an air bubble 3 was present. At the same time, the number of cycles that have already been completed is increased by 1, i.e. the cycle number is increased by 1.

In the event that the performance is within normal ranges (Yes in step S114), the cycle number is set to 0 (step S116) and then the process proceeds to step S102 of monitoring and adjusting the rotation speed, since it can be assumed that the air bubble 3 has been eliminated. On the other hand, if the If the rotation speed and/or the power are not in a normal range and at the same time the cycle number is less than a limit value ("No and cycle number less than limit value" in step S114), the process goes to step S110 of reducing the target speed in order to start a new attempt to remove the air bubble 3.

However, if the rotation speed and/or power are not within normal ranges and at the same time the cycle number is greater than or equal to the limit value (No and cycle number greater than or equal to the limit value in step S114), a signal is output to a user (step S118). This signal informs the user that an air bubble is present and allows the user to remove it.

After this signal is output, the speed (step S130) and the power (step S132) continue to be monitored. If the processing is then finished (Yes in step S134), the method ends (step S120). Otherwise (No in step S134), a check is made to see whether the bubble is still present (step S136). If this is the case (Yes in step S136), the system jumps to step S118. Otherwise, i.e. if the bubble could be removed by manual intervention by the user (No in step S136), the system jumps to step S114.

Figure 7 shows a method according to variant 2. Here, the speed of the drive is not regulated. Therefore, a motor voltage is output to it that corresponds to the speed level set by the user.

After a step S100 of starting the method, the rotational speed of the drive means 4 is set by a control device 8 (step S102). As described below, the rotational speed is used together with the power for bubble detection. At the same time (step S104) the performance of the drive 6 is monitored.

The next step is to check (step S106) whether the processing of the food has ended. This is the case, for example, if the user stops the processing manually or the program has expired. If this is the case (yes in step S106), the process ends (step S120).

However, if the processing of the food has not yet ended (No in step S106), as already previously described with reference to Figures 2 and 3, it is determined whether a bubble is present (step S108). If no such bubble is present (No in step S108), the rotational speed continues to be monitored (step S102). However, if a bubble is present (Yes in step S108), the motor voltage of the drive 4 is reduced (step S110) in order to lead to a collapse of the air bubble 3, as described, for example, with reference to Figure 4. After a certain preset period of time, the motor voltage is then increased to the default value (step S112) in order to return to the desired processing method. It is then checked (step S114) whether the rotational speed and the power are within normal ranges. Normal ranges are understood here to mean that the rotation speed and power correspond to the values within measurement tolerances that existed before the change in power and rotation speed that led to the detection of the presence of an air bubble 3. At the same time, the number of cycles that have already been completed is increased by 1, i.e. the cycle number is increased by 1.

In case the rotation speed and power are within normal ranges (Yes in step S114), the cycle number is set to 0 (step S116) and then it goes to step S102 of monitoring and setting the rotation speed, since it can be assumed that the air bubble 3 has been removed. On the other hand, if the rotation speed and/or the power are not in a normal range and at the same time the number of cycles is less than a limit value ("No and number of cycles less than a limit value" in step S114), the process goes to step S110 of reducing the motor voltage in order to start a new attempt to remove the air bubble 3.

However, if the rotation speed and/or power are not within normal ranges and at the same time the cycle number is greater than or equal to the limit value (No and cycle number greater than or equal to the limit value in step S114), a signal is output to a user (step S118). This signal informs the user that an air bubble is present and allows the user to remove it.

After this signal is output, the speed (step S130) and the power (step S132) continue to be monitored. If the processing is then finished (Yes in step S134), the method ends (step S120). Otherwise (No in step S134), a check is made to see if the bubble is still present (step S136). If this is the case (Yes in step S136), the process jumps to step S118. Otherwise (No in step S136), the process jumps to step S114.

Figure 8 shows a method according to variant 3. Here, the speed of the drive is not measured, but only the power is monitored. Here, too, the speed level set by the user corresponds internally to a target voltage to be output to the motor. In the normal case, ie when no bubble is to be removed, this target voltage corresponds to the actual output voltage, ie the electrical voltage output to the drive. Depending on the characteristic curve of the drive and the existing load, the result is for a certain output voltage a certain

Speed of the drive.

After a step S100 of starting the method,

(Step S104) the performance of the drive 6 is monitored.

The next step is to check (step S106) whether the processing of the food has ended. This is the case, for example, if the user stops the processing manually or the program has expired. If this is the case (yes in step S106), the process ends (step S120).

However, if the processing of the food is not yet complete (No in step S106), as previously described with reference to Figures 2 and 3, it is determined whether a bubble is present (step S108). If no such bubble is present (No in step S108), the performance continues to be monitored (step S102). However, if a bubble is present (Yes in step S108), the motor voltage of the drive 4 is reduced (step S110) in order to cause the air bubble 3 to collapse, as described, for example, with reference to Figure 4. After a certain preset period of time, the motor voltage is then increased to the default value (step S112) in order to return to the desired processing method. It is then checked (step S114) whether the performance is within normal ranges. Normal ranges are understood here to mean that the performance corresponds to the values within measurement tolerances that existed before the change in performance that led to the determination that an air bubble 3 is present. At the same time, the number of cycles that have already been completed is increased by 1, i.e. the cycle number is increased by 1.

In case the performance is within normal ranges (Yes in step S114), the cycle number is set to 0 (step S116) and then the process continues to step S104. of monitoring the performance, since it can be assumed that the air bubble 3 has been eliminated. On the other hand, if the performance is not in a normal range and at the same time the cycle number is less than a limit value ("No and cycle number less than limit value" in step S114), the process goes to step S110 of reducing the motor voltage in order to start a new attempt to remove the air bubble 3.

However, if the performance is not within normal ranges and at the same time the cycle number is greater than or equal to the limit value (No and cycle number greater than or equal to the limit value in step S114), a signal is output to a user (step S118). This signal informs the user that an air bubble is present and that the user can remove it.

After this signal is output, the power (step S132) continues to be monitored. If the processing is then finished (Yes in step S134), the method ends (step S120). Otherwise (No in step S134), a check is made to see whether the bubble is still present (step S136). If this is the case (Yes in step S136), the method jumps to step S118. Otherwise (No in step S136), the method jumps to step S114.

Figure 9 shows a method according to variant 4. Here, the speed of the drive is monitored but not regulated, but the power is not monitored. A motor voltage is therefore output to the drive that corresponds to the speed level set by the user.

After a step S100 of starting the method, the rotational speed of the drive means 4 is monitored (step S102). As described below, the rotational speed is used together with the power for bubble detection. A Motor voltage is output which corresponds to the speed level set by the user.

The next step is to check (step S106) whether the processing of the food has finished. This is the case, for example, if the user stops the processing manually or the program has expired. If this is the case (yes in step S106), the process ends (step S120).

However, if the processing of the food is not yet finished (No in step S106), as already described previously with reference to Figures 2 and 3, it is determined whether a bubble is present (step S108). If no such bubble is present (No in step S108), the rotational speed continues to be monitored (step S102). However, if a bubble is present (Yes in step S108), the motor voltage of the drive 4 is reduced (step S110) in order to cause the air bubble 3 to collapse, as described, for example, with reference to Figure 4. After a certain preset period of time, the motor voltage is then increased to the default value (step S112) in order to return to the desired processing method. It is then checked (step S114) whether the rotational speed is within normal ranges. Normal ranges are understood here to mean that the rotational speed corresponds to the values within measurement tolerances that existed before the change in the rotational speed that led to the determination that an air bubble 3 is present. At the same time, the number of cycles that have already been completed is increased by 1, i.e. the cycle number is increased by 1.

In case the rotation speed is within normal ranges (Yes in step S114), the cycle number is set to 0 (step S116) and then proceed to step S102 of monitoring the rotation speed because it can be assumed that the air bubble 3 has been removed. On the other hand, if the rotation speed is not in a normal range and at the same time the cycle number is less than a limit value ("No and cycle number less than limit value" in step S114), the process goes to step S110 of reducing the motor voltage in order to start a new attempt to remove the air bubble 3.

However, if the rotation speed is not within normal ranges and at the same time the cycle number is greater than or equal to the limit value (No and cycle number greater than or equal to the limit value in step S114), a signal is output to a user (step S118). This signal informs the user that an air bubble is present and allows the user to remove it.

After this signal is output, the speed (step S130) continues to be monitored. If the processing is then finished (Yes in step S134), the process ends (step S120). Otherwise (No in step S134), it is checked whether the bubble is still present (step S136). If this is the case (Yes in step S136), it jumps to step S118. Otherwise (No in step S136), it jumps to step S114.

Claims

Expectations 1. Device for determining whether a bubble is present in a food processed by a rotatingly driven working means, comprising: a determining device for determining at least one operating parameter of the drive (6) with which the working means (4) is driven, an evaluating device for determining whether a bubble (3) is present, wherein the evaluating device detects a bubble based on the output of the determining device, wherein the operating parameters comprise a power of the drive and/or a rotational speed of the drive. 2. Device according to claim 1, wherein the evaluation device only determines that a bubble (3) is present if the power drops by a predetermined amount within a predetermined period of time. 3. Device according to claim 2, further comprising a rotational speed determining device for determining the rotational speed of the working medium (4), wherein the evaluation device determines based on the determined rotational speed that a bubble (3) is present, wherein preferably it is only determined that a bubble is present if the rotational speed increases by a predetermined amount together with the drop in power. 4. Device according to claim 2 or 3, wherein the predetermined time period is in the range of 0.05-3 s, preferably 0.1-2 s. 5. Device according to one of the preceding claims, further comprising an output device for outputting that a bubble (3) is present. 6. Kitchen appliance (100) designed for processing foodstuffs (2) by means of a rotatingly driven working means (4), with a device according to one of the preceding claims, which is arranged to determine whether a bubble (3) is present in the foodstuff. 7. Kitchen appliance according to claim 6, wherein the kitchen appliance (100) is designed to temporarily reduce the voltage supplied to the drive of the motor from a target value when it is determined that a bubble (3) is present, and then the voltage is returned to the target value, or to temporarily reduce the target rotational speed of the working medium (4) from a target value when it is determined that a bubble (3) is present, and then the target rotational speed is returned to the target value. 8. Kitchen appliance according to claim 7, wherein the kitchen appliance (100) is designed to reduce the target rotational speed/voltage several times and then increase it when the evaluation device determines that a bubble (3) is present. 9. Kitchen appliance according to claim 7 or 8, wherein the kitchen appliance outputs a signal that a bubble (3) is present if it is determined after a predetermined number of reductions and returns of the target rotational speed/voltage that the bubble (3) is still present. 10. Kitchen appliance according to one of the preceding claims, in which the rotation speed is regulated. 11. A method for determining whether a bubble is present in a food product processed by a rotating working device, comprising the steps of: Determining at least one operating parameter of the drive (6) with which the working means (4) is driven, determining whether a bubble (3) is present based on the determined operating parameter(s), wherein the operating parameters comprise the power and/or the rotational speed of the drive. 12. The method of claim 11, wherein it is determined that a bubble (3) is present only if the power drops by a predetermined amount within a predetermined period of time. 13. A method according to claim 12, wherein the rotational speed of the working medium (4) is determined, wherein it is determined that a bubble (3) is present only when the rotational speed increases together with the drop in power. 14. Method according to one of claims 12 or 13, wherein the predetermined time period is in the range of 0.05-3 s, preferably 0.1-2 s. 15. The method of any one of claims 11 to 14, further comprising the step of indicating that a bubble (3) is present. 16. A method for removing a bubble from a food product processed by a rotating tool, comprising the following steps: Carrying out a method according to one of claims 11 to 15, if it is determined that a bubble (3) is present, temporarily reducing the target rotational speed of the working medium (4) starting from a target value, and then returning the target rotational speed to the target value or temporarily reducing the voltage supplied to the drive from a target value and then returning the voltage to the target value. 17. The method according to claim 16, wherein, if it is determined that a bubble (3) is present, the target rotational speed/voltage is reduced several times and then returned to the target value. 18. Method according to claim 16 or 17, further comprising the step of outputting a signal that a bubble (3) is still present if it is determined that a bubble (3) is still present after a predetermined number of reductions and returns of the target rotational speed/voltage.