Identifying stop of rotatable microwave dispensing device

Abstract

A method for identifying the cessation of a rotatable microwave distribution device (8) of a household microwave appliance (1), wherein during the feeding of microwaves (MW) into the cooking chamber (2) of the household microwave appliance (1), at least one microwave leakage radiation (LS) is monitored for the presence of angle-related repetitive fluctuations (Max1, Min, Max2), and if the absence of such fluctuations (Max1, Min, Max2) is identified, at least one action is triggered. A household microwave appliance (1) comprises: a cooking chamber (2), a microwave generator (5) for generating microwaves (MW), at least one rotatable microwave distribution device (8) for changing the field distribution of microwaves (MW) fed into the cooking chamber (2), at least one leakage radiation measuring device (11) for measuring microwave leakage radiation (LS), and a data processing device (10) configured to perform the method. The invention can be particularly advantageously applied to microwave cooking appliances, especially ovens with microwave functionality.

Description

Technical Field

[0001] This invention relates to a method for identifying the cessation of a rotatable microwave dispensing device in a household microwave appliance, wherein at least one microwave leakage radiation is measured during the feeding of microwaves into the cooking chamber of the household microwave appliance. The invention also relates to a household microwave appliance comprising a cooking chamber, a microwave generator for generating microwaves, at least one rotatable microwave dispensing device for altering the field distribution of microwaves fed into the cooking chamber, at least one leakage radiation measuring device for measuring microwave leakage radiation, and a data processing device configured to perform the method. This invention is particularly advantageously applicable to microwave cooking appliances, especially ovens with microwave functionality. Background Technology

[0002] DE 10 2014 105256 A1 discloses a method for operating a household appliance and a household appliance having at least one heating device for dielectric heating of a workpiece by electromagnetic radiation in at least one processing chamber. The document also includes at least one measuring system having at least one processing device. This measuring system is adapted and configured to generate electromagnetic measuring radiation. The measuring system has at least one transmitting device for at least temporarily emitting the electromagnetic measuring radiation into the processing chamber and at least one receiving device for at least temporarily receiving the measuring radiation emitted into the processing chamber. The measuring system is adapted and configured to detect at least one characteristic variable of the wave characteristics of the received measuring radiation. The processing device is adapted and configured to determine at least one measure of the spatial power distribution of radiation that can be delivered to the processing chamber by the heating device based on the change in the wave characteristics of the received measuring radiation relative to the emitted measuring radiation.

[0003] JP 2004259646 A discloses an apparatus having a heating chamber, a high-frequency oscillator for generating high-frequency waves, and a waveguide for guiding the high-frequency waves generated by the high-frequency oscillator into the heating chamber. The apparatus also includes two rotating antennas for radiating the high-frequency waves into the heating chamber, and a control device for controlling the rotational speed of each of the two rotating antennas.

[0004] EP 2 148 553 A1 discloses a method for detecting microwave leakage emission using a microwave sensor device. The temporal variation of the detected microwave emission is stored over a time interval by a storage device connected to the microwave sensor device. A portion of the stored microwave emission is evaluated. An apparatus is also provided for monitoring microwave leakage in a cooking appliance. The cooking appliance is equipped with a device for evaluating microwave leakage.

[0005] JP 2007335377 A discloses a microwave heating device, comprising: a microwave generating device; a waveguide for transmitting microwaves from the microwave generating device; a heating chamber for housing an object to be heated by microwaves; a plurality of rotating antennas for radiating microwaves from the waveguide into the heating chamber; a driving device for driving and rotating the rotating antennas; a temperature distribution detection device for detecting the temperature distribution inside the heating chamber; and a control device for controlling the angular position of the continuously rotating antennas by controlling the driving device in accordance with the detection result of the temperature distribution detection device.

[0006] EP 0 467 224 A1 discloses a high-frequency heating device and an electromagnetic wave detector used in the high-frequency heating device, which are arranged such that the state of food located in the heating chamber can be estimated by detecting microwaves in the heating chamber.

[0007] Using a rotatable antenna to introduce microwaves into the food processing or "cooking" chamber of a household microwave appliance is advantageous because the pattern of microwaves changes within the cooking chamber as the antenna rotates, thereby altering the distribution of localized areas of particularly high microwave power (so-called "hot spots"). This, in turn, allows for particularly uniform heating of the food items placed within the cooking chamber. However, the rotation of the rotatable antenna can stop unexpectedly, for example, in the event of a failure in the antenna motor driving the antenna. Since the antenna motor operates almost silently during normal operation, it is difficult for the user to detect such an unintentional stop. Furthermore, because the full microwave power is still being transmitted into the cooking chamber through the rotating antenna, and because not all food items are sensitive to the stop and make it immediately identifiable (especially liquids, which show almost no adverse effects), the user may not immediately notice the stop. As a result, a habituation effect associated with deteriorating heating may occur, or the aging of the appliance may be attributed to the deterioration of heating.

[0008] One possibility is to monitor the rotation or stopping of the rotating antenna using sensors such as reed contacts. However, the drawback of this approach is that such monitoring is unreliable during the lifespan of a household microwave appliance, as the entire antenna structure moves significantly during microwave operation due to thermal expansion (e.g., as the ceiling of the cooking room rises and falls), or it would only be possible through very high construction costs. Summary of the Invention

[0009] The objective of this invention is to at least partially overcome the shortcomings of the prior art, and in particular to provide the possibility of using a device with a simple construction, i.e., to reliably detect unintentional stopping of the rotating antenna of a home microwave device over a long period of time.

[0010] This task is solved according to the features of the independent claims. Advantageous embodiments are the subject of the dependent claims, the specification, and the drawings.

[0011] This task is solved by a method for identifying the stop of a rotatable microwave distribution device in a home microwave appliance, wherein...

[0012] - During the feeding of microwaves into the cooking chamber of the household microwave appliance, monitor at least one microwave leakage radiation for repetitive angle-related fluctuations, and

[0013] - If no such fluctuation is detected, at least one action is triggered.

[0014] This method has the following advantages: it can be implemented with relatively few components in a particularly cost-effective and simple manner. Since the required components are immovable, it also allows for particularly long-term implementation with a low probability of failure.

[0015] Furthermore, stops can be identified particularly reliably because, in order to determine a stop, only the desired target state (i.e., the changing pattern image) is measured and the functionality of the upstream components that cause the target state (e.g., antenna rotation) is not monitored.

[0016] By identifying stops, it is also possible to better protect components inside the cooking chamber from damage, such as protecting the antenna cover and / or components that absorb microwave energy (such as lights, door glass, silicone seals, etc.) from localized overheating.

[0017] Household microwave appliances can be standalone microwave devices or microwave combination devices. Microwave combination devices can be ovens, especially ovens, with additional microwave functions, or microwave devices with additional IR radiant heaters. Household microwave appliances can also be considered cooking appliances, particularly for processing food located in the cooking chamber by applying microwaves.

[0018] The at least one microwave dispensing device may have or at least one rotatable antenna (“rotating antenna”) through which microwaves generated by the microwave generator are fed into the cooking chamber. Alternatively or additionally, the at least one microwave dispensing device may have or at least one oscillator or stirrer.

[0019] Identifying a stoppage of a rotatable microwave distributor during microwave feeding specifically includes monitoring whether the microwave distributor is stopped during microwave operation, during which the microwave distributor should rotate. In other words, the method includes identifying a stoppage of the microwave distributor during microwave feeding under conditions where the rotation of the microwave distributor is activated or deactivated.

[0020] The at least one microwave leakage radiation may include microwave leakage radiation measured or detected at one or more leakage locations by means of one or more leakage radiation measuring devices. The microwave leakage radiation is particularly microwave radiation escaping from the cooking chamber through openings when the cooking chamber door is closed, such as through holes or gaps in the walls of the cooking chamber or in the muffle oven, or through gaps between the walls and the cooking chamber door. The leakage radiation measuring device is particularly located outside or on the outside of the cooking chamber, especially behind or near one or more openings, and is configured to detect the intensity of the microwave leakage radiation, particularly the energy, power, etc. of the microwave leakage radiation. The resulting measurement signal represents the intensity of the measured microwave leakage radiation.

[0021] The angle-related repetitive fluctuations in microwave leakage radiation typically occur only during normal rotational operation of the microwave distribution device (i.e., without erroneous stops), because it is assumed that the microwave field distribution in the cooking chamber, and therefore the microwave leakage radiation, strongly depends on the rotational position of the microwave distribution device, and that this field distribution remains at least substantially the same when the microwave distribution device is not rotating. If the microwave distribution device is therefore periodically set to the same rotational position sequence during microwave operation, this should be reflected in the corresponding angle-related repetitive fluctuations in microwave leakage radiation. If these fluctuations are absent during microwave operation using an active microwave distribution device, this can be considered a result of the microwave distribution device being stopped.

[0022] In particular, the fluctuations to be monitored can be automatically identified from microwave leakage radiation of one or more initial rotation angle sequences (especially complete rotations) of the microwave distribution device, especially templates (see below). The advantage of doing so is that characteristic fluctuations can be identified quickly and reliably and can be used to check for stops.

[0023] At least one triggerable action may include, for example, outputting a message to the user and / or notifying customer service.

[0024] In one extension, the microwave dispensing device is set to a pre-given time series of discrete rotation angles. This can be advantageous for eliminating rotation angles that are unsuitable for food processing.

[0025] In one design, the microwave distribution device rotates uniformly in a circular motion (e.g., continuously or gradually) and monitors for periodic repetitive fluctuations in microwave leakage radiation. This achieves the advantage of obtaining a particularly detailed and easily assessable curve of microwave leakage radiation measurements with respect to the rotation angle. For example, measurements can be recorded at intervals of 0.5°, 1°, 2°, 5°, etc., or measurements can be set at intervals of 0.5°, 1°, 2°, 5°, etc., for evaluation.

[0026] In one extension, the microwave distribution device rotates at a constant number of revolutions. In another extension, the rotation angle of the microwave distribution device changes gradually, for example, in steps of 0.5°, 1°, 2°, 5°, etc. In yet another extension, there are phases between microwave operation phases using a rotating microwave distribution device and phases using a fixed microwave distribution device. During the phases using the fixed microwave distribution device, it is not necessary to monitor for fluctuations in microwave leakage radiation.

[0027] In one design, the presence of at least one periodic repeating sequence of a template is observed during the monitoring of changes in microwave leakage radiation or the corresponding changes in the measurement signal of a leakage radiation measuring device that detects said microwave leakage radiation. Repeated identification of this template within the rotation rhythm of the microwave distribution device allows for particularly reliable identification of stops due to errors. This template may include one or more characteristic, easily identifiable curvilinear characteristics, such as one or more extreme points (maximum and / or minimum values), (rising or falling) edges, plateaus, etc. If this template does not repeat at the same angle or angular range during multiple rotations of the microwave distribution device, it can be assumed that the microwave distribution device has stopped due to an error. Here, the changing process may vary slightly with continuous rotation, particularly in intensity, but curvilinear characteristics such as the presence of one or more extreme points should be maintained qualitatively.

[0028] In one design, the microwave leakage radiation is checked for the presence of a periodically repeating sequence of at least one minimum and at least one maximum value, wherein consecutive minimums and maximums (in substantially any order) within an extension must also have a pre-given minimum interval (also known as "min / Max-Delta") between them. Advantageously, this leads to a criterion that can be easily evaluated for determining whether a stop or similar rotation exists. Therefore, to determine that a stop is not present, the value interval or value difference should not be less than a pre-given threshold in absolute value. For example, the pre-given minimum interval could be 20% of the average of the minimums and maximums involved.

[0029] However, it is also possible to check whether there are periodic repeating sequences of other curve characteristics in the microwave leakage radiation, including quantitative boundary conditions if necessary, or to check whether there are any missing periodic repeating sequences, such as the slope of the edge, the length of the plateau, etc.

[0030] In one design, the cross-correlation of a portion of the microwave leakage radiation variation process stored in a data memory, or the corresponding measurement signal, is continuously compared with a currently recorded portion of the variation process. This has the advantage that a pre-given template for determining the curve variation process can be eliminated. If the correlation metric for a corresponding angular range is lower than a pre-given correlation value, it can be inferred that the microwave distribution device is stopped. For example, the portion stored in the data memory can be automatically set based on one or more initial rotation angle sequences (particularly complete rotations) of the microwave distribution device. This setting may include random selection of one or more rotation angle portions; alternatively, one or more rotation angle portions may be selected based on pre-given criteria, such as based on specific characteristics of the curve or the presence of the shape of the variation process.

[0031] Generally, the presence / absence of multiple templates from different angles or angle ranges can be checked individually or separately, and the microwave dispensing device can be stopped when there is only one template, multiple templates, or all templates no longer repeat.

[0032] In one design, the at least one microwave leakage radiation comprises multiple microwave leakage radiations measured at different leakage locations, with each microwave leakage radiation monitored for angle-related repetitive fluctuations. This allows for the determination of stopping the rotatable microwave distribution device in a particularly reliable manner. This design is especially advantageous when one or more leakage locations provide insufficiently strong signals. It may be advantageous for this design that microwave leakage radiation from leakage locations that result in excessively low signals (where, for example, a specific signal threshold is not reached or exceeded during rotation) is not considered for stopping assessment. Generally, the stopping of microwave leakage radiation originating from different leakage locations can be examined individually or separately, and the stopping of the microwave distribution device can be determined when fluctuations in microwave leakage radiation at only one leakage location, fluctuations at multiple leakage locations, or fluctuations at all leakage locations are also identified as no longer repetitive.

[0033] In one design, the at least one microwave leakage radiation includes microwave leakage radiation occurring at multiple different leakage locations in a superimposed manner, and the presence of angle-related repetitive fluctuations in the at least one microwave leakage radiation is monitored. This results in a particularly simple and cost-effective design because the microwave sensor can measure microwave leakage radiation occurring at multiple leakage locations. In particular, microwave leakage radiation occurring at different leakage locations can generate measurement signals in the microwave sensor, which are superimposed into a total measurement signal. In an extension, the microwave sensor includes an electrical line (also referred to as a "sniffing line") passing through multiple leakage locations. Currents are induced in the same electrical line by the microwave leakage radiation, respectively, wherein the total current resulting from the superposition of each induced current corresponds to the measurement signal of the microwave sensor.

[0034] This task can also be accomplished by a microwave home appliance configured to run the methods described above. The microwave home appliance can be constructed similarly to this method and has the same advantages.

[0035] In one design, the household microwave appliance includes: a cooking chamber, a microwave generator for generating microwaves, a rotatable microwave distribution device for changing the field distribution of microwaves fed into the cooking chamber, at least one leakage radiation measuring device for measuring microwave leakage radiation, and a data processing device configured to perform the method.

[0036] The data processing device may correspond to the central control unit of the home microwave equipment. The data processing device may have a data storage device for storing measurement data.

[0037] The output of the microwave generator can be connected to one or more microwave guides or waveguides configured to conduct microwaves generated by the microwave generator into the cooking chamber. To feed microwaves into the cooking chamber, the microwave guides specifically lead to one or more rotating antennas. The microwave generator may include an inverter. The microwave generator may be a magnetron or a semiconductor-based microwave generator. In principle, the household microwave device may have one or more rotating antennas, one or more oscillators, and / or one or more microwave generators.

[0038] The above-described features, characteristics, and advantages of the present invention, as well as the ways in which they are implemented, will become clearer and easier to understand in conjunction with the illustrative description of the following embodiments, which will be explained in more detail with reference to the accompanying drawings. Attached Figure Description

[0039] Figure 1 A household microwave device is shown in a side sectional view;

[0040] Figure 2 The diagram illustrates the intensity changes of microwave leakage radiation from the rotating antenna during rotation and when it is stationary.

[0041] Figure 3 It shows Figure 2 The measurement curve shown is a segment within the time range during the rotation of the rotating antenna. Detailed Implementation

[0042] Figure 1 A sketch of a household microwave appliance 1 is shown in a side sectional view, the appliance having a cooking chamber 2. The cooking chamber 2 is surrounded by a cooking chamber wall 3, which has a front loading opening that can be closed with a door 4. For processing food items (not shown) located in the cooking chamber 2, the household microwave appliance 1 has at least one microwave generator 5, and if necessary, additional heating elements, such as one or more resistance heating elements (not shown). The household microwave appliance 1 can thus be, in particular, an oven with microwave functionality.

[0043] Microwave generator 5 is connected to microwave guide 6, the other side of which leads to dome 7 arranged on the top plate. Microwaves MW generated by microwave generator 5 are guided into dome 7 via microwave guide 6, from where they reach cooking chamber 2. For this purpose, a microwave distribution device in the form of a rotatable antenna 8 is provided in dome 7, by which microwaves MW from microwave guide 6 are emitted. The rotating antenna 8 can be rotated by means of a motor, particularly a stepper motor 9, acting as an antenna motor, for example, rotating quasi-continuously in 1° increments.

[0044] The stepper motor 9 can be operated by means of a control device 10, which is also connected to a leakage radiation measuring device in the form of a microwave sensor 11 and is configured to evaluate the measurement data Sig generated by the microwave sensor 11. The microwave sensor 11 is arranged outside or behind the cooking chamber wall 3, and behind or near an opening 12 in the cooking chamber wall 3 that allows microwave leakage radiation LS to pass through. The intensity of the microwave leakage radiation LS typically varies along with the field distribution of microwave MW in the cooking chamber 2 during the rotation of the rotating antenna 8.

[0045] There is also an operating device 13 coupled to the control device 10. The operating device 13 may have one or more operating elements and one or more display devices, such as in the form of a touch screen. The control device 10 is configured to output one or more instructions or messages to the user on the display device of the operating device 13.

[0046] The control device 10 is also configured to detect the cessation of the activated rotating antenna 8 and then trigger at least one action. Therefore, the control device 10 also functions as a data processing device or evaluation circuit. Specifically, the control device 10 is configured to monitor, during the feeding of microwaves into the cooking chamber 2, whether there are angle-related repetitive fluctuations in the microwave leakage radiation LS, measured by means of the microwave sensor 11, during the rotational operation of the rotating antenna 8, and if the control device 10 detects the absence of such fluctuations, trigger at least one action, such as outputting a corresponding message to the operating device 13 and / or sending it to a mobile user terminal, etc.

[0047] Figure 2 The change in intensity of microwave leakage radiation LS, measured by microwave sensor 11 as mV Sig, is shown as a curve of time t in s, with reference to time t.

[0048] After microwave operation begins, the measurement curve alternately shows the time period M during which the rotating antenna 8 rotates at a constant speed and the time period S during which the rotating antenna 8 does not rotate. The measurement signal Sig changes only slightly during time period S, while the measurement signal Sig shows strong fluctuations during time period M. Therefore, the absence of such fluctuations indicates that the rotating antenna 8 is stationary.

[0049] Figure 3 It shows Figure 2 The measurement curve shown is a segment within a time period M. Time period M comprises three consecutive complete rotations RP1, RP2, and RP3. Since the rotating antenna 8 rotates at a constant speed during time period M, the time point on the x-axis corresponding to the measured value corresponds to the corresponding rotation angle of the rotating antenna 8. In the illustrated embodiment, the first maximum value Max1, the minimum value Min, and the second maximum value Max2 alternate in the signal variation process or curve during one complete rotation of the rotating antenna 8.

[0050] For example, the extreme values ​​Max1, Min, and Max2 can be automatically identified from the curve changes during the first complete rotation RP1 using the control device 10. Then, the control device 10 can monitor whether these extreme values ​​Max1, Min, and Max2 reappear or periodically in subsequent rotations RP2 and RP3 when the rotation of the rotating antenna 8 is activated. Specifically, it can also monitor whether the minimum interval (Min / Max-Delta) between Max1 and Min and / or the minimum interval between Min and Max2 is higher than a corresponding threshold. This threshold could, for example, be 20% of the average of the relevant minimum values ​​Min and maximum values ​​Max1 and Max2.

[0051] Therefore, the rotation RP1 can be inspected by means of the control device 10.

[0052] | Sig (Max1) - Sig (Min) | 0.2 [Sig (Max1) + Sig(Min)] / 2, and / or

[0053] | Sig (Max2) - Sig (Min) | 0.2 [Sig (Max2) + Sig(Min)] / 2

[0054] Whether this holds true. This is given here during time period M, because the estimate is 80 - 35 = 45. 0.2 * 57.5 = 11.5 or 120 - 35 = 85 The condition 0.2·77.5 = 15.5 holds true, but these boundary conditions were not met during the time period S. Similarly, the value interval between Max1 and Max2 can also be monitored.

[0055] If the control device 10 identifies that the extreme values ​​Max1, Min, Max2 do not reappear during the subsequent rotations RP2 and RP3, or that one or all of the above interval conditions are not met, the control device 10 triggers at least one action.

[0056] Of course, the present invention is not limited to the embodiments shown.

[0057] Generally speaking, "one" can be understood as singular or plural, especially in the sense of "at least one" or "one or more", as long as it is not explicitly excluded, such as through expressions like "exactly one".

[0058] Numerical descriptions can also accurately include the numbers being described, as well as common tolerance ranges, unless explicitly excluded.

[0059] List of reference numerals

[0060] 1. Home microwave equipment

[0061] 2. Cooking Room

[0062] 3. Cooking room walls

[0063] 4 doors

[0064] 5. Microwave generator

[0065] 6. Microwave Guide

[0066] 7. Dome

[0067] 8 Rotating Antenna

[0068] 9 stepper motors

[0069] 10. Control device

[0070] 11 Microwave Sensors

[0071] 12 Openings

[0072] 13 Operating device

[0073] LS microwave leakage radiation

[0074] M refers to the time period during which the rotating antenna rotates.

[0075] Max1 First maximum value

[0076] Max2 is the second maximum value.

[0077] Min minimum value

[0078] MW microwave

[0079] RP1 First complete rotation

[0080] RP2 Second complete rotation

[0081] RP3 Third complete rotation

[0082] S refers to the time period during which the rotating antenna does not rotate.

[0083] Sig measurement signal

[0084] t represents time.

Claims

1. A method for identifying the stopping of a rotatable microwave distribution device (8) for a household microwave device (1), wherein - During the feeding of microwaves (MW) into the cooking chamber (2) of the household microwave appliance (1), monitor at least one microwave leakage radiation (LS) for angle-dependent repetitive fluctuations, and - If no such fluctuation is detected, at least one action is triggered.

2. The method as described in claim 1, wherein, At least one microwave distribution device (8) rotates uniformly in a circular motion and monitors whether the microwave leakage radiation (LS) exhibits periodic repetitive fluctuations.

3. The method as described in claim 2, wherein, The monitoring process detects the presence of at least one periodic repeating sequence of a template during changes in microwave leakage radiation (LS).

4. The method of claim 3, wherein, Monitor the microwave leakage radiation (LS) for a periodic repeating sequence of at least one minimum (Min) and at least one maximum (Max1, Max2), wherein the minimum and the maximum have a pre-given minimum interval between each other.

5. The method according to any one of claims 3 to 4, wherein, The cross-correlation of a stored portion of the microwave leakage radiation (LS) variation process is continuously compared with the currently recorded portion of the variation process.

6. The method according to any one of claims 1 to 4, wherein, The at least one microwave leakage radiation (LS) includes multiple microwave leakage radiation (LS) measured at different leakage locations (12), and each microwave leakage radiation is monitored for repetitive fluctuations related to the angle.

7. The method according to any one of claims 1 to 4, wherein, The at least one microwave leakage radiation (LS) includes microwave leakage radiation (LS) appearing at multiple different leakage locations (12) in a superimposed manner, and the presence of angle-related repetitive fluctuations in the at least one microwave leakage radiation (LS) is monitored.

8. The method according to any one of claims 1 to 4, wherein, At least one rotatable microwave distribution device (8) includes at least one rotating antenna and / or at least one oscillator.

9. A household microwave device (1), comprising: - Cooking Room (2) - At least one microwave generator (5) for generating microwaves (MW). - At least one rotatable microwave distribution device (8) for changing the field distribution of microwaves (MW) fed into the cooking chamber (2). - At least one leakage radiation measuring device (11) for measuring microwave leakage radiation (LS), and - A data processing apparatus (10) configured to perform the method according to any one of claims 1 to 8.

10. The household microwave device (1) as described in claim 9, wherein, The household microwave device (1) is an oven with microwave function.

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