Cooking appliance

Abstract

Cooking appliance (10) with a resonance chamber (24), a vibration generator (25) associated with the resonance chamber (24), an airflow generator (18) that can generate an airflow directed towards the vibration generator (25) in such a way that standing waves with a known wavelength are formed in the resonance chamber (24), a microphone (34) associated with the resonance chamber (24), a temperature measurement unit (36) that can generate a signal corresponding to the temperature (T) of the atmosphere in the resonance chamber (24), and a control unit (38) to which the microphone (34) and the temperature measurement unit (36) are connected.

Description

[0001] The invention relates to a cooking appliance, in particular a cooking appliance for professional use, for example in restaurants, canteens and large-scale catering.

[0002] Such cooking appliances can be designed as so-called combi steamers, i.e., cooking appliances in which the food to be cooked is cooked using hot air and / or steam. For such cooking appliances, it is necessary to know the humidity in the cooking chamber, i.e., the water content of the atmosphere within the cooking chamber, for optimal food preparation.

[0003] EP 1 300 079 B1 discloses a cooking appliance with a resonance chamber for determining the humidity in the cooking chamber. The resonance chamber is designed as a tube, closed off at one end by a loudspeaker and containing a microphone. The frequency is used to determine the speed of sound and thus the humidity.

[0004] DE 101 43 841 A1 shows a cooking appliance in which the speed of sound is measured by a time-of-flight measurement using an ultrasonic device that emits sound that is reflected by the air baffle.

[0005] Various methods are commonly used to measure humidity, such as measuring the pressure drop across the fan impeller of the cooking appliance. However, the results of such methods also depend on other external factors, such as air pressure, which can lead to measurement inaccuracies.

[0006] It is therefore an object of the invention to provide a cooking appliance that can precisely determine the humidity present in the cooking chamber of the cooking appliance using simple means.

[0007] The problem is solved by a cooking appliance with a resonance chamber, a vibration generator associated with the resonance chamber, an airflow generator capable of generating an airflow directed toward the vibration generator such that standing waves of a known wavelength form in the resonance chamber, a microphone associated with the resonance chamber, a temperature measurement unit capable of generating a signal corresponding to the temperature of the atmosphere in the resonance chamber, and a control unit to which the microphone and the temperature measurement unit are connected. The invention is based on the fundamental idea of ​​determining the humidity of the atmosphere within the cooking chamber of the cooking appliance by measuring the speed of sound, since the speed of sound in the cooking chamber depends not only on the temperature but also on the material composition of the atmosphere in the cooking chamber.

[0008] To determine the speed of sound, acoustic vibrations are excited in the resonance chamber by the vibration generator and the airflow generator, resulting in standing waves of known wavelengths. The acoustic vibrations in the resonance chamber are generated by the airflow generator blowing air onto the vibration generator. For this purpose, the vibration generator is positioned relative to the airflow generator in such a way that an airflow generated by the airflow generator strikes the vibration generator.

[0009] The design of the vibration generator causes the air within the resonant chamber to vibrate, as is common with woodwind instruments, for example. Figuratively speaking, the vibration generator, together with the resonant chamber, can be thought of as a whistle or flute. In this way, vibrations are generated in the resonant chamber, which are primarily the fundamental vibration of the resonant chamber and its overtones.

[0010] The microphone, which can be acoustically coupled to the resonance chamber, can record the temporal progression of the vibrations in the resonance chamber. The control system can then use the microphone signal to determine the frequency of the acoustic vibrations, particularly the fundamental frequency, or the frequency spectrum of the acoustic vibrations in the resonance chamber. The controller uses the determined frequencies and the temperature value generated by the temperature measurement unit to determine the humidity within the cooking chamber. This allows the humidity of the atmosphere in the cooking chamber to be measured quickly, easily, and reliably.

[0011] The temperature value unit can be a temperature sensor that directly measures the temperature of the atmosphere in the resonance chamber. Alternatively, the temperature sensor measures the temperature in the cooking chamber, which can be converted into the temperature in the resonance chamber. However, it is also conceivable that the temperature value unit transmits a different value to the control unit, for example, the target temperature of the cooking appliance's heating system, which the control unit can use to determine the temperature in the resonance chamber.

[0012] Preferably, the airflow generator is a fan wheel on the cooking appliance. This eliminates the need for additional components beyond those already present to generate the airflow.

[0013] In one embodiment of the invention, the cooking appliance has at least one air guiding device between the air flow generator and the vibration generator, whereby the air flow generator can be blown in a more targeted and thus more efficient manner.

[0014] In one embodiment of the invention, the temperature value unit is designed as a temperature sensor located in the cooking chamber of the cooking appliance. This transmits a particularly reliable temperature value to the control unit. Under certain circumstances, the control unit corrects the received temperature signal to obtain a more precise indication of the temperature in the resonance chamber, for example, if the temperature in the cooking chamber is known to be higher or lower than the temperature in the resonance chamber.

[0015] Preferably, the control unit contains a module for acoustic spectral analysis, in particular a Fourier analysis and / or a correlation function module. This module enables the control unit to determine the relevant frequency spectrum of the oscillations excited in the resonator, thereby improving the accuracy of the humidity determination, in particular through the simultaneous evaluation of multiple overtones.

[0016] In one embodiment of the invention, the vibration generator has a separation edge for the airflow generated by the airflow generator, such as a blade or a blowing opening, onto which the airflow from the airflow generator impinges. This greatly simplifies the design of the vibration generator. Blades are used for sound generation in recorders, for example, while blowing openings are used in transverse flutes.

[0017] For example, the cooking chamber of the cooking appliance is the resonance chamber, which means that no additional components are necessary to create the resonance chamber.

[0018] In a further embodiment of the invention, the resonance chamber is located within a resonator that is open to the cooking chamber of the cooking appliance. The resonator is a geometrically clearly defined space that is comparatively small compared to the cooking chamber, for example, in the shape of a cylinder or a rectangular cavity. This allows the dimensions and geometries of the resonance chamber to be freely selected.

[0019] The resonator is preferably located in the cooking chamber of the cooking appliance. This allows for particularly good thermal and acoustic coupling between the cooking chamber and the resonator. The resonator can be open at its lower end and / or positioned so that the resonator is also cleaned by the washing solution of the cooking appliance when the cooking chamber is cleaned. The temperature sensor can also be located on the resonator.

[0020] The resonator is preferably designed as a tube, which makes it simple and cost-effective to manufacture. For example, the tube is 20 cm long and / or has an inner diameter of 1.5 cm to 2 cm. The tube can also be open on one or both sides and / or be arranged vertically in the cooking chamber. It is also conceivable to provide at least one opening in the wall of the tube to influence the vibrations generated in the resonator.

[0021] The vibration generator can be provided at one end of the tube so that the air in the resonance chamber can be excited particularly efficiently by the vibration generator.

[0022] In one embodiment of the invention, the end of the tube at which the vibration generator is provided has an opening or, in particular, is completely open, with the edge of the opening being designed as the cutting edge of the vibration generator. In this way, the vibration generator can be manufactured simultaneously with the resonator.

[0023] In one embodiment of the invention, the cooking appliance has a cavity that is acoustically coupled to the resonance chamber at a coupling point, with the microphone provided in the cavity. This allows the microphone to be arranged outside the resonance chamber and the cooking chamber.

[0024] The cavity can be another tube or hose. The diameter of the hose or pipe differs from the diameter of the resonator at the coupling point to create an impedance jump at the coupling point, which reduces the coupling between the cavity and the resonator and thus couples less power out of the resonator. The length of the cavity can also be selected so that the resonance frequency of the system consisting of the resonant chamber and cavity differs significantly from the resonance frequency of the resonant chamber, so that a clear distinction can be made in the frequency spectrum between the vibrations in the resonant chamber alone and any vibrations occurring in the system consisting of the cavity and the resonant chamber.

[0025] Preferably, the cavity has a membrane arranged in the coupling point to protect the microphone from water vapor, dirt and heat.

[0026] For example, the cavity can be shaped to dampen or absorb vibrations at its end facing away from the coupling point, in particular tapering towards the end, in particular tapering to a point, so that vibrations in the cavity are dampened and no standing waves can form in the cavity.

[0027] The cavity can also be provided with sound-absorbing material, particularly at its end facing away from the coupling point, so that vibrations in the cavity are not reflected.

[0028] In one design variant, the cavity widens in a funnel shape toward the coupling point. This allows for the use of a thin membrane with a large surface area and prevents reflections at the coupling point.

[0029] In a further embodiment of the invention, the microphone is provided in the resonance chamber, which enables a direct and accurate measurement of the amplitudes of the vibrations in the resonance chamber.

[0030] Preferably, the microphone or coupling point is positioned in the region of the maximum sound pressure of one or more of the natural vibrations of the resonant chamber, thereby achieving good coupling of the microphone to the resonator, thus improving the quality of the measurement. Other positions for the microphone or coupling point are also conceivable, providing favorable coupling for multiple natural vibrations. One possible position for the microphone or coupling point is the center of the tube relative to its longitudinal axis.

[0031] Further features and advantages of the invention will become apparent from the following description and the accompanying drawings, to which reference is made. In the drawings: - Fig. 1 a first embodiment of a cooking appliance according to the invention schematically in section, - Fig. 2 an enlarged view of a part of the cooking appliance according to Fig. 1, - Fig. 3 shows an exemplary frequency spectrum determined by the control unit of the cooking appliance according to the invention, - Fig. 4 an enlarged view of a part of a second embodiment of a cooking appliance according to the invention, and - Fig. 5 a third embodiment of a cooking appliance according to the invention schematically in section.

[0032] In Fig. 1 shows a cooking appliance 10 with a cooking chamber 12 and a technical chamber 14.

[0033] The cooking appliance 10 is intended for professional use in commercial kitchens and large-scale catering. It is, for example, a combi steamer that can prepare various foods using hot air and / or superheated steam. For this purpose, an atmosphere is created in the cooking chamber 12 that has the desired temperature and humidity for cooking. For reasons of clarity, the heating device and evaporator have been omitted.

[0034] The cooking chamber 12 and the technical chamber 14 are separated from each other by a rear wall 16 of the cooking chamber 12.

[0035] On the rear wall 16, an air flow generator 18 designed as a fan wheel and a resonator 20 are arranged on the cooking chamber side.

[0036] Between the fan wheel and the resonator 20, a funnel 21 and an air guiding device 22 are provided in the cooking chamber 12, as shown in the enlarged illustration of the Fig. 2 can be seen.

[0037] The funnel 21 is designed as a nozzle, wherein the opening of the funnel 21 with the larger diameter faces the air flow generator 18 designed as a fan wheel.

[0038] The air guiding device 22, designed as a channel, is connected to the opening of the funnel 21 with the smaller diameter. The air guiding device 22 opens parallel to the upper opening of the resonator 20 toward the resonator 20.

[0039] The resonator 20 is attached to the rear wall 16 by means of a fastening 23.

[0040] The resonator 20 is designed as a tube and has, for example, a length L of 20 cm and an inner diameter between 1.5 cm and 2 cm. Both ends of the tube are open, so that the resonator 20 is a resonator open on both sides. However, it is also conceivable that only one side of the resonator 20 is open.

[0041] The resonator 20 defines a resonance chamber 24 within the tube. The resonance chamber 24 is thus located within the cooking chamber 12 and is open toward the cooking chamber 12.

[0042] The tube and thus the resonator 20 are arranged vertically in the cooking chamber 12. As a result, when cleaning the cooking appliance 10, the washing solution also penetrates the tube of the resonator 20 and thus cleans the resonator 20.

[0043] In the embodiment shown, the edge of the upper opening of the resonator 20 is designed as a vibration generator 25, here as a tear-off edge, more precisely as a cutting edge 26.

[0044] The mouth of the air guiding device 22 is directed towards the cutting edge 26, i.e. towards the vibration generator 25.

[0045] A cavity 27 is provided on the resonator 20, which can be formed by a hose or another tube.

[0046] The cavity 27 opens into the resonance chamber 24 of the resonator 20, wherein the point at which the cavity 27 merges into the resonance chamber 24 is referred to as the coupling point 28.

[0047] At the coupling point, a thin membrane 30 is provided which closes the cavity 27 from the resonance chamber 24 so that neither hot air, nor water vapor, nor dirt can penetrate into the cavity 27.

[0048] At the same time, however, the membrane 30 can vibrate, so that vibrations can be transmitted from the resonance chamber 24 into the cavity 27. The cavity 27 and the resonance chamber 24 are thus acoustically coupled.

[0049] In the embodiment shown, the cavity 27 opens centrally into the resonance chamber 24, viewed in the longitudinal direction of the resonator 20. In other words, the coupling point 28 in the embodiment shown is located halfway along the length L / 2 of the resonator 20.

[0050] The diameter of the cavity 27 at the coupling point 28 differs from the diameter of the resonance chamber 24. For example, the diameter of the cavity 27 is significantly smaller.

[0051] The cavity 27 extends in the other direction, ie from the resonator 20 through the rear wall 16 into the technical room 14.

[0052] At the end of the cavity 27 facing away from the resonator 20, the tube or pipe defining the cavity 27 tapers to a point and is closed. Thus, the cavity 27 is shaped to dampen and absorb vibrations at its end facing away from the coupling point 28.

[0053] Sound-absorbing material 32 can also be provided in the cavity 27.

[0054] In the embodiment shown, a microphone 34 is provided in the area of ​​the cavity 27 which is located within the technical room 14.

[0055] In addition, in the embodiment shown, a temperature value unit 36 ​​in the form of a temperature sensor is provided on the resonator 20.

[0056] A control unit 38 is located in the technical room 14 and is connected to the microphone 34 and the temperature sensor 36. The control unit 38 receives signals from both the microphone 34 and the temperature sensor 36.

[0057] The control unit 38 has a module 40 that receives the signals from the microphone 34 and can perform a spectral analysis of the received signal using a Fourier analysis and / or a correlation function. In this way, the module 40 can determine the frequency spectrum ( Fig. 3) of the microphone signal and thus determine the frequency spectrum of the vibrations in the resonance chamber 24.

[0058] The cooking appliance 10 can now determine the humidity within the cooking chamber 12 as follows: During operation of the cooking appliance 10, the fan wheel rotates and creates an air flow along the rear wall 16. This air flow, indicated by the arrows in Fig. 2, is partially captured by the funnel 21 and accelerated into the air guiding device 22.

[0059] From the air guiding device 22, the air now flows in the direction of the resonator 20 onto the vibration generator 25. The air flow runs parallel to the upper opening of the resonator 20.

[0060] The vibration generator 25, i.e. the upper edge of the resonator 20 formed as a cutting edge 26, is also located in the air stream.

[0061] The air flow is divided by the cutting edge 26 and generates acoustic vibrations within the resonator 20 or the resonance chamber 24, similar to a pan flute.

[0062] The oscillations forming in the resonator 20 and thus in the resonance chamber 24 are standing acoustic waves or natural oscillations of the resonator 20. In addition to the fundamental oscillation or fundamental tone of the resonator 20, one or more overtones can also be excited in the resonator 20.

[0063] Only overtones can be excited by targeted overblowing, i.e. by generating a very strong air flow and thus a high pressure on the vibration generator 25.

[0064] By means of one or more openings 42 in the wall of the resonator 20 or the tube of the resonator 20, it is possible to influence which overtones can develop in the resonator 20.

[0065] The fundamental oscillation of the resonator 20 has pressure nodes at the two openings of the resonator tube 20 and a pressure bulge at half the length L / 2. This pressure bulge thus forms at the coupling point 28 and causes the oscillations to propagate through the membrane 30 into the cavity 27. In the cavity 27, the acoustic oscillations are then picked up by the microphone 34 and transmitted as an electrical signal to the control unit 38, more specifically to the spectral analysis module 40.

[0066] In order to prevent a standing wave from forming within the cavity 27, the cavity 27 is provided with the sound-absorbing material 32 and tapers at its end facing away from the coupling point 28.

[0067] In addition, the diameter of cavity 27 is selected to be smaller than that of resonant chamber 24 or resonator 20, thus reducing the coupling between the system of cavity 27 and resonant chamber 24 and the resonant chamber 24 alone. If the coupling is too high, and especially if the cavity 27 is too large, too much power would be extracted from the natural oscillation in the resonant chamber 24, thereby damping this natural oscillation.

[0068] In addition, by a suitable choice of the length of the cavity 27, the resonance frequency of the system consisting of cavity 27 and resonance chamber 24 can be selected sufficiently far away from the resonance frequency of the resonance chamber 24 alone.

[0069] The spectral analysis module 40 then evaluates the signal from the microphone 34, for example, using a Fourier analysis and / or correlation functions, and determines the frequency spectrum of the signal. The frequency spectrum of the signal corresponds to the frequency spectrum of the vibrations in the resonance chamber 24. Such a frequency spectrum is shown, for example, in Fig. 3 shown.

[0070] Using the frequency spectrum, the frequency F0 of the fundamental oscillation is now determined. In this case, the frequency F0 can be easily determined from the frequency spectrum.

[0071] In cases where the fundamental oscillation of resonator 20 has not been excited and only overtones are present in the frequency spectrum, the frequency F0 of the fundamental oscillation can be determined based on the distances between the frequencies F1, F2, and F3 of the overtones. The frequencies F1, F2, and F3 of the overtones can also be used to correct the frequency value F0 to improve the accuracy of the measurement.

[0072] The value of the frequency F0 of the fundamental oscillation determined in this way is then transferred by the module 40 to the control unit 38 for spectral analysis.

[0073] The control unit 38 also receives a temperature value T from the temperature value unit 36. In the embodiment shown, the temperature value corresponds directly to the temperature of the resonator 20 and thus to the temperature T of the resonance chamber 24 and can therefore be used immediately.

[0074] If the temperature sensor of the temperature value unit 36 ​​is not provided directly on the resonator 20, it may be necessary for the control unit 38 to correct the obtained temperature value. For example, it is conceivable that the resonator 20 is located outside the cooking chamber 12, but is connected to it and filled with the atmosphere of the cooking chamber, while the temperature sensor is provided inside the cooking chamber 12, so that the temperature in the resonance chamber 24 is lower than the measured temperature in the cooking chamber 12.

[0075] However, it is also conceivable that the temperature value unit 36 ​​derives the temperature value from the cooking appliance's control system, for example, the setpoint temperature of the heating device. In this case, the control unit 38 corrects the temperature value accordingly, resulting in a value of the temperature T in the resonance chamber 24.

[0076] Using the frequency F0 of the fundamental oscillation and the temperature T in the resonance chamber 24, the control unit 38 can now determine the humidity in the cooking chamber 12.

[0077] To do this, the speed of sound c within the resonator is determined in a first step, which is given by c = λ0 · F0. The wavelength λ0 of the fundamental oscillation is known due to the geometry of the resonator 20 and, in the case shown, is approximately 2L.

[0078] The speed of sound c depends on the temperature T and the composition of the atmosphere within the resonance chamber 24: c=(κatmo⋅Rmol⋅T)Matmo, where R mol is the universal gas constant, K atmo the adiabatic exponent and M atmo the molar mass of the gas mixture of water vapor and air in the cooking chamber atmosphere.

[0079] M atmo and K atmoor their ratio can be determined, since the speed of sound c, the universal gas constant R mol and the temperature T are known.

[0080] In this way, the composition of the atmosphere in the resonance chamber 24 can be determined, ie the proportion of water vapor to air in the atmosphere, whereby the humidity in the atmosphere in the cooking chamber 12 can also be determined.

[0081] Of course, the two equations can also be inserted into each other and solved for the ratio of M atmo to K atmo be dissolved.

[0082] Further embodiments of the cooking appliance 10 according to the invention are described below, which essentially correspond to the first embodiment. Identical or functionally equivalent parts are designated by the same reference numerals, and only the differences will be discussed.

[0083] Fig. Figure 4 shows an enlarged view of a part of a cooking appliance 10 according to the invention according to a second embodiment. The representation of the Fig. 4 corresponds to the representation of the Fig. 2 to the first embodiment.

[0084] In contrast to the first embodiment, no cavity 27 is provided, but the microphone 34 is provided directly in the resonator 20, i.e. in the resonance chamber 24.

[0085] The microphone 34 can be arranged at the location where the coupling point 28 was arranged in the first embodiment, ie in the longitudinal direction of the tube of the resonator 20 approximately at half the length L / 2.

[0086] The arrangement of the microphone 34 in the resonance chamber 24 enables direct measurement in the resonance chamber 24. However, in this embodiment, the microphone 34 is also exposed to the hot and sometimes greasy atmosphere in the cooking chamber 12, which significantly increases the demands on the load capacity of the microphone 34.

[0087] In Fig. 5 shows a third embodiment of a cooking appliance 10 according to the invention in section.

[0088] In the third embodiment according to Fig. 5, no separate resonator 20 is provided, but the cooking chamber 12 itself serves as a resonance chamber 24.

[0089] The method for generating acoustic vibrations in the resonance chamber 24 also differs from that of the first embodiment.

[0090] In the Fig. In the embodiment shown in Figure 5, the funnel 21 is omitted.

[0091] A plate 46 is attached to the rear wall 16 by means of a bracket 44 as the vibration generator 25. The plate 46 can vibrate relative to the bracket 44.

[0092] Furthermore, the temperature value unit 36 ​​is located on the rear wall 16, in this embodiment also designed as a temperature sensor.

[0093] In the embodiment shown, the microphone 34 is arranged centrally on the floor of the cooking chamber 12. It is, of course, also conceivable to mount the microphone on a side wall or the ceiling of the cooking chamber 12.

[0094] During operation of the cooking appliance 10, the air flow generator 18, designed as a fan wheel, generates an air flow that strikes the plate 46. The air flow causes the plate 46 to vibrate, similar to a harmonica, thereby generating acoustic vibrations.

[0095] The geometry and the type of suspension of the plate 46 are selected such that the sounds generated by the plate 46 (ie the acoustic vibrations generated by the plate 46) are adapted to the geometry of the cooking chamber 12 so that the plate 46 can excite the natural vibrations within the cooking chamber 12 or the resonance chamber 24.

[0096] This creates standing acoustic waves in the cooking chamber 12, which can be picked up by the microphone 34.

[0097] The frequency of the vibrations occurring in the cooking chamber 12 and the humidity within the cooking chamber 12 are determined in the same way as already described for the first embodiment.

[0098] Naturally, the features of the embodiments shown can be combined with each other as desired. In particular, it is conceivable that the embodiment according to Fig.1 can also be designed without a separate resonator 20 and the cooking chamber 12 is also used as a resonance chamber 24.

Claims

[1] Cooking appliance (10) with a resonance chamber (24), a vibration generator (25) associated with the resonance chamber (24), an air flow generator (18) which can generate an air flow directed towards the vibration generator (25) in such a way that standing waves with a known wavelength are formed in the resonance chamber (24), a microphone (34) associated with the resonance chamber (24), a temperature value unit (36) which can generate a signal corresponding to the temperature (T) of the atmosphere in the resonance chamber (24), and a control unit (38) to which the microphone (34) and the temperature value unit (36) are connected. [2] Cooking appliance (10) according to claim 1, characterized by that the air flow generator (18) is a fan wheel of the cooking appliance (10). [3] Cooking appliance (10) according to one of the preceding claims, characterized by that the cooking appliance (10) has at least one air guiding device (22) between the air flow generator (18) and the vibration generator (25). [4] Cooking appliance (10) according to one of the preceding claims, characterized by that the temperature value unit (36) is designed as a temperature sensor which is arranged in the cooking chamber (12) of the cooking appliance (10). [5] Cooking appliance (10) according to one of the preceding claims, characterized by that the control unit (38) contains a module (40) for acoustic spectral analysis, in particular a Fourier analysis and / or a correlation function module. [6] Cooking appliance (10) according to one of the preceding claims, characterized by that the vibration generator (25) has a separation edge for the flow generated by the air flow generator (18), such as a cutting edge (26) or a blowing opening. [7] Cooking appliance (10) according to one of the preceding claims, characterized by that the cooking chamber (12) of the cooking appliance (10) is the resonance chamber (24). [8] Cooking appliance (10) according to one of claims 1 to 6, characterized bythat the resonance chamber (24) is located within a resonator (20) which is open to the cooking chamber (12) of the cooking appliance (10). [9] Cooking appliance (10) according to claim 8, characterized by that the resonator (20) is arranged in the cooking chamber (12) of the cooking appliance (10). [10] Cooking appliance (10) according to claim 8 or 9, characterized by that the resonator (20) is designed as a tube. [11] Cooking appliance (10) according to claim 10, characterized by that the vibration generator (25) is provided at one end of the tube. [12] Cooking appliance (10) according to claim 11, if dependent on claim 6, characterized by that the end of the tube on which the vibration generator (25) is provided has an opening, in particular is completely open, wherein the edge of the opening is designed as the cutting edge (26) of the vibration generator (25). [13] Cooking appliance (10) according to one of the preceding claims, characterized bythat the cooking appliance (10) has a cavity (27) which is acoustically coupled to the resonance chamber (24) at a coupling point (28), wherein the microphone (34) is provided in the cavity (27). [14] Cooking appliance (10) according to claim 13, characterized by that the cavity (27) has a membrane (30) which is provided in the coupling point (28). [15] Cooking appliance (10) according to claim 13 or 14, characterized by that the cavity (27) is shaped to dampen or absorb vibrations at its end facing away from the coupling point (28), in particular tapers towards the end, in particular tapers to a point. [16] Cooking appliance (10) according to one of claims 13 to 15, characterized by that the cavity (27), in particular at its end facing away from the coupling point (28), is provided with sound-absorbing material (32). [17] Cooking appliance (10) according to one of claims 13 to 16, characterized bythat the cavity (27) widens in a funnel shape towards the coupling point (28). [18] Cooking appliance (10) according to one of claims 1 to 12, characterized by that the microphone (34) is provided in the resonance chamber (24). [19] Cooking appliance (10) according to one of the preceding claims, characterized by that the microphone (34) or the coupling point (28) is arranged in the region of the maximum of the sound pressure of one or more of the natural oscillations of the resonance chamber (24).

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