EP4642251A1 - Method and equipment for the treatment of food by ultrasound - Google Patents
Method and equipment for the treatment of food by ultrasoundInfo
- Publication number
- EP4642251A1 EP4642251A1 EP23836599.3A EP23836599A EP4642251A1 EP 4642251 A1 EP4642251 A1 EP 4642251A1 EP 23836599 A EP23836599 A EP 23836599A EP 4642251 A1 EP4642251 A1 EP 4642251A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- frequency
- driving signal
- ultrasound
- generator
- ultrasonic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- A—HUMAN NECESSITIES
- A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
- A23L—FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES, NOT OTHERWISE PROVIDED FOR; PREPARATION OR TREATMENT THEREOF
- A23L5/00—Preparation or treatment of foods or foodstuffs, in general; Food or foodstuffs obtained thereby; Materials therefor
- A23L5/30—Physical treatment, e.g. electrical or magnetic means, wave energy or irradiation
- A23L5/32—Physical treatment, e.g. electrical or magnetic means, wave energy or irradiation using phonon wave energy, e.g. sound or ultrasonic waves
Definitions
- the present invention relates generally to the field of food processing using ultrasound. More specifically, the present invention relates to a method of food processing using ultrasound and related equipment comprising one or more ultrasound transducers.
- the agro-food industry still uses methods and techniques for processing and treating food raw materials that result in a reduction in organoleptic and nutritional qualities due to the high volumes produced. Performing chemical treatments, refining treatments and/or high- temperature heat treatments on food raw materials inevitably results in a deterioration of the chemical and physical properties of the produced food, with a consequent reduction in its quality.
- ultrasound for applications such as cleaning in water with detergents or for welding is widely known in the state of the art.
- the use of ultrasound for food preparation is also well known, but current solutions on the market are not able to optimise ultrasound generation for food processing.
- waveco ⁇ Next Cooking Generation
- the main advantages of using ultrasound are the reduction of food preparation time, the reduction of cooking temperatures and the reduction of the bacterial load, which increases the shelf life of the final product.
- Ultrasonic generators use one or more ultrasonic transducers, in particular piezoelectric transducers. Ultrasound is generated through the mechanical vibration of the piezoelectric transducer based on a received electrical drive signal, which determines the mechanical vibration that is generated by the transducer.
- a drive signal generator performs an amplitude modulation of a carrier signal, obtained as a succession of pulses, using a low-frequency modulating signal (50 Hz) derived from a mains supply voltage.
- the signal generated by the modulator is supplied to the transducer by means of a step-up transformer, which typically has a transformation ratio of 1 :2, so as to electrically separate the signal -generating part of the drive signal from the transducer that is immersed in the tank.
- a step-up transformer typically has a transformation ratio of 1 :2, so as to electrically separate the signal -generating part of the drive signal from the transducer that is immersed in the tank.
- piezoelectric transducers which have a resonance frequency f r , typically in the range from 33kHz to 38kHz, and are driven with a drive signal of the type illustrated in figure 2.
- This drive signal is basically obtained by means of a carrier signal consisting of a succession of pulses, oscillating at the resonance frequency f r , which is amplitude modulated, with a modulating signal consisting of a succession of pulses at a low modulation frequency f m (typically less than 1 kHz).
- this is a rectified carrier signal oscillating at a frequency of approximately 38 kHz, which has an amplitude modulated by a rectified sinusoidal modulating signal oscillating at a frequency of 200 Hz.
- this type of drive signal is obtained with the circuit shown in figure 1, by deriving the modulating signal from the rectified 50 Hz mains supply voltage, generating the carrier signal as a succession of pulses at 38 kHz and then generating the drive signal shown, by amplitude modulation of the carrier signal with the modulating signal.
- the amplitude modulating signal causes pulsed energy to be generated in the tank in which the ultrasonic transducer is immersed, which serves to increase cavitation and provide vibrations that improve energy distribution and increase the surface effects on the treated products.
- An objective of the present invention is to propose a method of food processing using ultrasound in which the drive signal of the ultrasound transducers is generated in a way that optimises heat generation, energy dissipation and noise.
- FIG. 1 illustrates a block diagram of an apparatus known to generate ultrasounds according to the present disclosure, comprising an amplitude modulator configured to generate driving pulses for piezoelectric transducers by amplitude modulating a succession of pulses;
- FIG. 2 is a time diagram of a typical drive signal of an ultrasonic transducer, where the drive signal is obtained by amplitude modulating a succession of pulses;
- FIG. 4 illustrates a block diagram of an ultrasound generating apparatus according to the present disclosure, comprising a controlled amplifier generating drive pulses for piezoelectric transducers;
- FIG. 5 shows an example of a controlled amplifier that can be used in the diagram in Figure 4;
- - Figure 6 shows the spectrum of a drive signal of an ultrasonic transducer, in which the drive signal is obtained by frequency modulation, according to one aspect of the present invention
- - Figure 7 is a block diagram of another ultrasound generating apparatus according to the present disclosure, comprising a switching power supply controlled by a microprocessor unit to generate a modulated voltage
- FIG. 8 shows an example of a full-bridge multi-level generator that may be used in the equipment of figure 7.
- foodstuffs are processed using ultrasound generated by transducers driven with a drive signal that does not contain those peaks of harmonics at audible frequencies shown in the spectrum of figure 3.
- a drive signal that does not contain those peaks of harmonics at audible frequencies shown in the spectrum of figure 3.
- the drive signal is generated by reducing the peaks of the harmonics at audible frequencies relative to the peak of the harmonic at the resonance frequency of the driven transducer, but without completely cancelling out all low-frequency components.
- this can be achieved by generating the drive signal by amplitude or frequency modulating a succession of pulses at the ultrasonic resonant frequency of the ultrasonic transducer, such that the drive signal has harmonic peaks at audible frequencies having respective amplitudes less than at least -40dB and greater than -80dB relative to an amplitude of one harmonic of the drive signal at the ultrasonic resonant frequency.
- the apparatus of figure 1 is not suitable for generating such a drive signal, if only because the step-up transformer inevitably amplifies the low- frequency components better than the high-frequency components, which are more prone to attenuation due to the ferromagnetic material of which the step-up transformer is made. Consequently, in the known equipment of figure 1, the step-up transformer amplifies the low-frequency components to a greater extent than the high-frequency components and this worsens the peak generation of the components at audible frequencies.
- the ultrasonic treatment was effective because low- frequency harmonics were not eliminated, but were present with significant amplitudes.
- Tests carried out by the Applicant have shown that in order to have an effective ultrasonic treatment of foodstuffs, the peaks of the harmonics at audible frequencies of the drive signal must have an amplitude that is -80dB greater than the amplitude of the peak at the ultrasonic resonance frequency of the transducer.
- Drive signals with harmonic peaks at audible frequencies that have respective amplitudes less than at least -40dB and greater than -80dB relative to an amplitude of one harmonic of the drive signal at the ultrasonic resonant frequency can be generated in several ways.
- a first way is the one implemented in the prototype equipment that performs amplitude modulation, in which the modulating signal - which, for example, can be generated from a rectified mains supply voltage - and the carrier signal - consisting of a succession of pulses at the ultrasonic resonance frequency - are generated so that the amplitude spectrum of the corresponding drive signal has the above-mentioned characteristics.
- the reduction of low-frequency harmonic peaks with respect to peaks at the piezoelectric transducer's resonance frequency can also be achieved by generating the piezoelectric transducer's drive signal using a DSP (Digital Signal Processing) microprocessor-based generator, so as to comply with the above constraints on the spectral content of the drive signal.
- DSP Digital Signal Processing
- an apparatus for treating foodstuffs by means of ultrasound comprises a tank (not illustrated in Figure 4) for treating foodstuffs by means of ultrasound constructed of material suitable for contact with foodstuffs, for example stainless steel, and intended to be filled with water and to receive the foodstuffs to be treated.
- the equipment further comprises an ultrasonic generator, collectively referred to as 1, having an electrical power supply unit 2, referred to as a PSU (Power Supply Unit) at least one microprocessor unit 4 and at least one ultrasonic transducer 7.
- the generator 1 comprises a transformer 9 and an impedance matching circuit 3 for efficient power transfer between the amplifier 5 generating the drive signal and the transducer 7.
- the microprocessor unit 4 is functionally connected to the amplifier 5 so as to control its operation and to feedback control the drive signal provided to the transducer 7. According to one aspect, the microprocessor unit 4 via a readout circuit 6 is configured to read values of a voltage at the ends of the ultrasonic transducer 7 and/or values of a current drawn by the ultrasonic transducer 7 and to control the amplifier 5 so as to generate said drive signal to adjust a desired phase relationship between the voltage and the current.
- a drive signal with a desired amplitude spectrum can be generated through appropriate control by the microprocessor unit 4.
- another way is to generate the drive signal by means of a frequency modulation of the pulse succession in a circle of the ultrasonic resonance frequency, e.g. in a circle between 1kHz and 2kHz.
- such frequency modulation can be realised using the schematic diagram in Figure 4, or even by equipping an ultrasound food processing apparatus with a drive signal generator comprising a frequency modulator stage configured to perform frequency modulation of the pulse sequence for the ultrasound transducer(s) 7.
- FIG 6 which shows a spectrum of a drive signal obtained by frequency modulation centred at the transducer's resonance frequency
- a drive signal is generated in which there are low-frequency components, but the amplitudes of the peaks at audible frequencies are in the range of -40dB and -80dB relative to the amplitude of the peaks at the ultrasonic resonance frequency of the transducer.
- standing waves do not occur in the water-filled tank in which the food to be treated with ultrasound is immersed, and at the same time the audible noise is at tolerable levels.
- a transducer 7 may be a piezoelectric element with a desired resonance frequency, or carrier frequency.
- a piezoelectric type transducer 7 with a resonance frequency of 35 kHz may be used.
- the electrical power supply 9 is a switched-mode power supply (SMPS) configured to be controlled by the microprocessor unit 4 by generating a modulated voltage, and the drive signal is output by a multilevel bridge PWM stage 8 fed with the modulated voltage, which can be for example realised as illustrated in figure 8.
- SMPS switched-mode power supply
- the microprocessor unit 4 is, in this case, functionally connected to the switching power supply 9 and is further configured to generate a control voltage to regulate the voltage generated by the power supply 9.
Landscapes
- Health & Medical Sciences (AREA)
- Nutrition Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Food Science & Technology (AREA)
- Polymers & Plastics (AREA)
- Apparatuses For Generation Of Mechanical Vibrations (AREA)
Abstract
The present invention relates to an ultrasound generator implementable in an apparatus for the treatment of foodstuffs by means of ultrasound and configured to generate, in particular, a drive signal for one or more transducers, preferably of the piezoelectric type, characterised by a specific resonance frequency. The generator includes a system for frequency control of the drive signal so as to optimise the generation of ultrasound by reducing noise and heat dissipation and controlling the energy delivered to the food to be treated.
Description
METHOD AND EQUIPMENT FOR THE TREATMENT OF FOOD BY ULTRASOUND
Technical field of the invention
The present invention relates generally to the field of food processing using ultrasound. More specifically, the present invention relates to a method of food processing using ultrasound and related equipment comprising one or more ultrasound transducers.
State of the Art
The agro-food industry still uses methods and techniques for processing and treating food raw materials that result in a reduction in organoleptic and nutritional qualities due to the high volumes produced. Performing chemical treatments, refining treatments and/or high- temperature heat treatments on food raw materials inevitably results in a deterioration of the chemical and physical properties of the produced food, with a consequent reduction in its quality.
In recent years, food processing techniques with less negative impact on the quality of the final product are finding use. These include, for example, processing techniques based on the use of ultrasound.
The use of ultrasound for applications such as cleaning in water with detergents or for welding is widely known in the state of the art. The use of ultrasound for food preparation is also well known, but current solutions on the market are not able to optimise ultrasound generation for food processing. For example, there is a professional machine on the market, produced by the company Next Cooking Generation, called waveco©, which uses ultrasound to process food such as meat, fish, vegetables and pastry products. The main advantages of using ultrasound are the reduction of food preparation time, the reduction of cooking temperatures and the reduction of the bacterial load, which increases the shelf life of the final product.
Ultrasonic generators use one or more ultrasonic transducers, in particular piezoelectric transducers. Ultrasound is generated through the mechanical vibration of the piezoelectric transducer based on a received electrical drive signal, which determines the mechanical vibration that is generated by the transducer.
An example of equipment suitable for generating drive signals is schematically illustrated in figure 1. A drive signal generator performs an amplitude modulation of a carrier signal, obtained as a succession of pulses, using a low-frequency modulating signal (50 Hz) derived from a mains supply voltage. Finally, the signal generated by the modulator is
supplied to the transducer by means of a step-up transformer, which typically has a transformation ratio of 1 :2, so as to electrically separate the signal -generating part of the drive signal from the transducer that is immersed in the tank. Conveniently, there is also an impedance matching block inserted between the transformer and the transducer in order to maximise the power transfer to the transducer.
Generally, piezoelectric transducers are used, which have a resonance frequency fr , typically in the range from 33kHz to 38kHz, and are driven with a drive signal of the type illustrated in figure 2. This drive signal is basically obtained by means of a carrier signal consisting of a succession of pulses, oscillating at the resonance frequency fr , which is amplitude modulated, with a modulating signal consisting of a succession of pulses at a low modulation frequency fm (typically less than 1 kHz).
In the specific example shown in figure 2, this is a rectified carrier signal oscillating at a frequency of approximately 38 kHz, which has an amplitude modulated by a rectified sinusoidal modulating signal oscillating at a frequency of 200 Hz. According to a known technique, this type of drive signal is obtained with the circuit shown in figure 1, by deriving the modulating signal from the rectified 50 Hz mains supply voltage, generating the carrier signal as a succession of pulses at 38 kHz and then generating the drive signal shown, by amplitude modulation of the carrier signal with the modulating signal.
The amplitude modulating signal causes pulsed energy to be generated in the tank in which the ultrasonic transducer is immersed, which serves to increase cavitation and provide vibrations that improve energy distribution and increase the surface effects on the treated products.
Unfortunately, machines using piezoelectric transducers driven with such drive signals are particularly noisy.
Summary
Studies carried out by the applicant in an attempt to address the noise problem of ultrasonic processing machines have shown that, although low frequencies, i.e. frequencies below 1 kHz, are very useful in some applications, they introduce harmonics and sub-harmonics at audible frequencies that do not match the resonance frequency of piezoelectric transducers. This is illustrated as an example in the semi-logarithmic scale graph in figure 3 where the amplitude spectrum of the drive signal in figure 2 is shown. The graph in figure 3 shows the main harmonic component of the modulating signal at
200 Hz and its upper harmonics in the audible frequency range.
Without being bound to any theory, it is believed that low-frequency amplitude modulation would generate excess cavitation, unwanted heat and dissipation, and lead to substantial mechanical vibrations that make the equipment very noisy.
An objective of the present invention is to propose a method of food processing using ultrasound in which the drive signal of the ultrasound transducers is generated in a way that optimises heat generation, energy dissipation and noise.
This and other objectives are achieved, according to a first aspect of the present invention, by a method of treatment as defined in the annexed independent claim 1. Also disclosed are apparatus for treating foodstuffs immersed in a tank filled with water and subjected to ultrasound.
Further advantageous aspects of the invention are the subject of dependent claims, the content of which is to be understood as an integral part of this description.
Brief description of the figures
Further features and advantages of the present invention will become clear from the detailed description below, which is given by way of non-limiting example with reference to the accompanying drawings, wherein
- Figure 1 illustrates a block diagram of an apparatus known to generate ultrasounds according to the present disclosure, comprising an amplitude modulator configured to generate driving pulses for piezoelectric transducers by amplitude modulating a succession of pulses;
- Figure 2 is a time diagram of a typical drive signal of an ultrasonic transducer, where the drive signal is obtained by amplitude modulating a succession of pulses;
- Figure 3 shows the spectrum of the drive signal from figure 2;
- Figure 4 illustrates a block diagram of an ultrasound generating apparatus according to the present disclosure, comprising a controlled amplifier generating drive pulses for piezoelectric transducers;
- Figure 5 shows an example of a controlled amplifier that can be used in the diagram in Figure 4;
- Figure 6 shows the spectrum of a drive signal of an ultrasonic transducer, in which the drive signal is obtained by frequency modulation, according to one aspect of the present invention;
- Figure 7 is a block diagram of another ultrasound generating apparatus according to the present disclosure, comprising a switching power supply controlled by a microprocessor unit to generate a modulated voltage;
- Figure 8 shows an example of a full-bridge multi-level generator that may be used in the equipment of figure 7.
Detailed description
According to one aspect of the present disclosure, foodstuffs are processed using ultrasound generated by transducers driven with a drive signal that does not contain those peaks of harmonics at audible frequencies shown in the spectrum of figure 3. To obviate the limitations of known equipment, one might think that it would be sufficient to filter the components of the ultrasonic transducer drive signals with high-pass filtering that lets harmonics pass from the resonance frequency upwards to eliminate the frequencies in the audible range, but this simple action would not result in a functioning equipment. In fact, eliminating the components at audible frequencies from the drive signal of the ultrasonic transducer would lead to the generation of standing waves in the tank in which the foodstuffs are immersed, so there would be no propagation of energy in space and the desired effect on the foodstuffs to be treated would not occur.
To remedy this, according to the method of the present disclosure, the drive signal is generated by reducing the peaks of the harmonics at audible frequencies relative to the peak of the harmonic at the resonance frequency of the driven transducer, but without completely cancelling out all low-frequency components.
According to one aspect of this disclosure, this can be achieved by generating the drive signal by amplitude or frequency modulating a succession of pulses at the ultrasonic resonant frequency of the ultrasonic transducer, such that the drive signal has harmonic peaks at audible frequencies having respective amplitudes less than at least -40dB and greater than -80dB relative to an amplitude of one harmonic of the drive signal at the ultrasonic resonant frequency.
It can therefore be understood that the apparatus of figure 1 is not suitable for generating such a drive signal, if only because the step-up transformer inevitably amplifies the low- frequency components better than the high-frequency components, which are more prone to attenuation due to the ferromagnetic material of which the step-up transformer is made. Consequently, in the known equipment of figure 1, the step-up transformer amplifies the
low-frequency components to a greater extent than the high-frequency components and this worsens the peak generation of the components at audible frequencies.
Tests carried out by the Applicant on a working prototype realised by modifying the known apparatus of figure 1 have shown that a significant noise reduction can be achieved. This prototype equipment was constructed from the equipment in figure 1 by replacing the elevating transformer with an isolating transformer having a unity transformation ratio, and by increasing the power associated with the carrier signal as much as possible so that the power of the drive signal supplied to the transducer has a minimum level sufficient to function correctly. Analysing the spectrum of the drive signal thus generated, it was noted that the amplitude at the transducer's resonance frequency was at least 40dB greater than the amplitude of the peak at audible frequency due to amplitude modulation, so that the noise generated by the prototype equipment was significantly reduced. Furthermore, the ultrasonic treatment was effective because low- frequency harmonics were not eliminated, but were present with significant amplitudes. Tests carried out by the Applicant have shown that in order to have an effective ultrasonic treatment of foodstuffs, the peaks of the harmonics at audible frequencies of the drive signal must have an amplitude that is -80dB greater than the amplitude of the peak at the ultrasonic resonance frequency of the transducer.
Drive signals with harmonic peaks at audible frequencies that have respective amplitudes less than at least -40dB and greater than -80dB relative to an amplitude of one harmonic of the drive signal at the ultrasonic resonant frequency can be generated in several ways. A first way is the one implemented in the prototype equipment that performs amplitude modulation, in which the modulating signal - which, for example, can be generated from a rectified mains supply voltage - and the carrier signal - consisting of a succession of pulses at the ultrasonic resonance frequency - are generated so that the amplitude spectrum of the corresponding drive signal has the above-mentioned characteristics.
According to one aspect, the reduction of low-frequency harmonic peaks with respect to peaks at the piezoelectric transducer's resonance frequency can also be achieved by generating the piezoelectric transducer's drive signal using a DSP (Digital Signal Processing) microprocessor-based generator, so as to comply with the above constraints on the spectral content of the drive signal.
With reference to Figures 4 and 5, an apparatus for treating foodstuffs by means of
ultrasound according to the present invention comprises a tank (not illustrated in Figure 4) for treating foodstuffs by means of ultrasound constructed of material suitable for contact with foodstuffs, for example stainless steel, and intended to be filled with water and to receive the foodstuffs to be treated. The equipment further comprises an ultrasonic generator, collectively referred to as 1, having an electrical power supply unit 2, referred to as a PSU (Power Supply Unit) at least one microprocessor unit 4 and at least one ultrasonic transducer 7. Preferably, the generator 1 comprises a transformer 9 and an impedance matching circuit 3 for efficient power transfer between the amplifier 5 generating the drive signal and the transducer 7.
The microprocessor unit 4 is functionally connected to the amplifier 5 so as to control its operation and to feedback control the drive signal provided to the transducer 7. According to one aspect, the microprocessor unit 4 via a readout circuit 6 is configured to read values of a voltage at the ends of the ultrasonic transducer 7 and/or values of a current drawn by the ultrasonic transducer 7 and to control the amplifier 5 so as to generate said drive signal to adjust a desired phase relationship between the voltage and the current.
Using an amplifier 5 of the type illustrated in figure 5, i.e. a class D amplifier, a drive signal with a desired amplitude spectrum can be generated through appropriate control by the microprocessor unit 4.
According to the present disclosure, another way is to generate the drive signal by means of a frequency modulation of the pulse succession in a circle of the ultrasonic resonance frequency, e.g. in a circle between 1kHz and 2kHz.
According to one aspect, such frequency modulation can be realised using the schematic diagram in Figure 4, or even by equipping an ultrasound food processing apparatus with a drive signal generator comprising a frequency modulator stage configured to perform frequency modulation of the pulse sequence for the ultrasound transducer(s) 7.
As illustrated in figure 6, which shows a spectrum of a drive signal obtained by frequency modulation centred at the transducer's resonance frequency, with frequency modulation a drive signal is generated in which there are low-frequency components, but the amplitudes of the peaks at audible frequencies are in the range of -40dB and -80dB relative to the amplitude of the peaks at the ultrasonic resonance frequency of the transducer. As a result, standing waves do not occur in the water-filled tank in which the food to be treated with ultrasound is immersed, and at the same time the audible noise is
at tolerable levels.
Any type of ultrasound transducer known in the state of the art may be used as an ultrasound transducer. According to one aspect, a transducer 7 may be a piezoelectric element with a desired resonance frequency, or carrier frequency. For example, at least one piezoelectric type transducer 7 with a resonance frequency of 35 kHz may be used.
According to an alternative embodiment of the present invention, as illustrated in the block diagram in figure 7, the electrical power supply 9 is a switched-mode power supply (SMPS) configured to be controlled by the microprocessor unit 4 by generating a modulated voltage, and the drive signal is output by a multilevel bridge PWM stage 8 fed with the modulated voltage, which can be for example realised as illustrated in figure 8.
In particular, the microprocessor unit 4 is, in this case, functionally connected to the switching power supply 9 and is further configured to generate a control voltage to regulate the voltage generated by the power supply 9.
The present invention has thus far been described with reference to a preferred form of embodiment thereof. It is to be understood that other embodiments may be contemplated which share the same inventive core with the one described herein, as defined by the appended claims.
Claims
1. A method of treating food using ultrasound, comprising: procuring and installing an ultrasonic treatment equipment having:
- a tank configured to be filled with water and to contain food immersed in the water;
- at least one ultrasound transducer (6) configured to be driven by an electric driving signal and to emit ultrasound corresponding to the electric driving signal in said tank when filled with water;
- a generator (5) configured to generate said electric driving signal as a succession of pulses at an ultrasonic resonance frequency of the ultrasound transducer (6); said method comprising the operation of generating said driving signal by modulating said succession of pulses in amplitude or in frequency so that said driving signal has harmonic peaks at audible frequencies having respective amplitudes lower than at least - 40dB and higher than -80dB with respect to an amplitude of a harmonic of the drive signal at the resonant ultrasonic frequency.
2. The method according to claim 1, wherein said driving signal is generated by amplitude modulating said succession of resonance ultrasonic frequency pulses with a frequency modulating signal at a frequency which is multiple of a frequency of a mains supply voltage of said generator (5).
3. The method according to claim 1, wherein said driving signal is generated by frequency modulating said succession of pulses in a neighborhood of said ultrasonic resonant frequency comprised between 1kHz and 2kHz.
4. An apparatus for processing food using ultrasound, comprising an ultrasound generator (1), the ultrasound generator (1) comprising at least:
- a tank configured to be filled with water and to contain food immersed in the water;
- at least one ultrasound transducer (7) configured to be driven by an electric driving signal and to emit ultrasound corresponding to the electric driving signal in said tank when filled with water;
- a generator (5) configured to generate said electric driving signal as a succession of pulses at an ultrasonic resonance frequency of the ultrasound transducer (7); wherein said generator (5) is configured to generate said driving signal by modulating said succession of pulses in amplitude or in frequency so that said driving signal has harmonic peaks at audible frequencies having respective amplitudes lower than at least -
40dB and higher of -80dB with respect to an amplitude of a harmonic of the drive signal at the ultrasonic resonant frequency.
5. The apparatus according to claim 4, configured to implement the method according to claim 3, comprising at least one frequency modulator stage configured to generate said driving signal by frequency modulating said succession of pulses in a neighborhood of said resonant ultrasonic frequency between 1kHz and 2kHz, and functionally connected to control the ultrasound transducer (7) with said driving signal.
6. The apparatus according to claim 4 or 5, wherein the apparatus comprises a microprocessor unit (4) configured to read values of a voltage across the ultrasound transducer (7) or values of a current absorbed by the ultrasound transducer (7) and to control said generator (5) so as to generate said driving signal to regulate a desired phase relationship between said voltage and said current.
7. The apparatus according to one of claims 4 to 6, wherein said generator comprises a class D switching amplifier (5) controlled by the microprocessor unit (4), said apparatus further comprising a power supply (2) configured to power said amplifier (5) with a regulated voltage.
8. The apparatus according to one of claims 4 to 6, wherein said generator comprises a switching power supply (9) configured to be controlled by the microprocessor unit (4) generating a modulated voltage, as well as a multilevel bridge PWM stage (8) powered with said modulated voltage and configured to generate said driving signal.
9. The apparatus according to one of claims 4 to 8, wherein said at least one transducer (6) comprises a piezoelectric element with a respective resonance frequency.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT102022000027006A IT202200027006A1 (en) | 2022-12-28 | 2022-12-28 | METHOD AND EQUIPMENT FOR TREATMENT OF FOOD BY ULTRASOUND |
| PCT/IB2023/063004 WO2024141871A1 (en) | 2022-12-28 | 2023-12-20 | Method and equipment for the treatment of food by ultrasound |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP4642251A1 true EP4642251A1 (en) | 2025-11-05 |
Family
ID=85792220
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP23836599.3A Pending EP4642251A1 (en) | 2022-12-28 | 2023-12-20 | Method and equipment for the treatment of food by ultrasound |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP4642251A1 (en) |
| IT (1) | IT202200027006A1 (en) |
| WO (1) | WO2024141871A1 (en) |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6095087B1 (en) * | 2016-04-19 | 2017-03-15 | 正明 坂口 | Ultrasonic treatment apparatus and ultrasonic treatment method |
-
2022
- 2022-12-28 IT IT102022000027006A patent/IT202200027006A1/en unknown
-
2023
- 2023-12-20 EP EP23836599.3A patent/EP4642251A1/en active Pending
- 2023-12-20 WO PCT/IB2023/063004 patent/WO2024141871A1/en not_active Ceased
Also Published As
| Publication number | Publication date |
|---|---|
| IT202200027006A1 (en) | 2024-06-28 |
| WO2024141871A1 (en) | 2024-07-04 |
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