WO2013078325A1 - Commande d'une application d'énergie radiofréquence sur la base de la température - Google Patents

Commande d'une application d'énergie radiofréquence sur la base de la température Download PDF

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Publication number
WO2013078325A1
WO2013078325A1 PCT/US2012/066274 US2012066274W WO2013078325A1 WO 2013078325 A1 WO2013078325 A1 WO 2013078325A1 US 2012066274 W US2012066274 W US 2012066274W WO 2013078325 A1 WO2013078325 A1 WO 2013078325A1
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WO
WIPO (PCT)
Prior art keywords
energy
acoustic
signal
sound velocity
processor
Prior art date
Application number
PCT/US2012/066274
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English (en)
Inventor
Steven Robert Rogers
Ronen Cohen
Ben ZICKEL
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Goji Ltd.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Goji Ltd. filed Critical Goji Ltd.
Publication of WO2013078325A1 publication Critical patent/WO2013078325A1/fr

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/64—Heating using microwaves
    • H05B6/6447—Method of operation or details of the microwave heating apparatus related to the use of detectors or sensors

Definitions

  • This application relates to devices and methods for heating an object by radio frequency (RF) energy, and more particularly but not exclusively to devices and methods for using temperature-based control of RF energy application to heat an object to a temperature above 250°C.
  • RF radio frequency
  • thermocouples e.g., made of glass fibers
  • Glass fiber thermocouples are limited to measure temperatures below 250°C.
  • Metallic thermocouples can be used to measure temperatures above 250°C.
  • IR sensors or IR cameras are used to measure IR temperature measurements of an object are limited to measurements of surface temperatures only.
  • Some exemplary aspects of the disclosure include apparatuses and methods for applying electromagnetic energy to an object in an energy application zone and measuring a temperature inside the object.
  • the temperature inside the object may be determined by measuring a sound velocity in the object or a signal related to the sound velocity in the object, for example, a signal indicative of sound velocity inside the object.
  • the temperature inside the object may be measured during the application of electromagnetic energy.
  • a signal related to the sound velocity in the object may include any measurable signal that may be received from an ultrasound sensor, for example, a signal indicative of the sound velocity.
  • the measured signal related to the sound velocity may be used to determine the temperature of the object, for example, by a processor, using data correlating the sound velocity or the signal indicative thereof to the temperature.
  • the data may be stored in a lookup table on a memory associated with the processor.
  • Signals related to sound velocity may be used for determining the temperature of many different objects, for example, solid objects (e.g., food items, soot particles trapped in a filter), liquid objects (e.g., chemical solutions), or gaseous objects (e.g., natural gas in a gas turbine).
  • Sound velocity or signals related to sound velocity may further be used to determine a temperature of an object in a fluid environment, for example, a filter in an exhaust gas emission reduction device (e.g., a Diesel Particulate Filter, DPF).
  • DPF Diesel Particulate Filter
  • Some embodiments may involve a method of heating an object.
  • the method may comprise: applying RF energy to the object; detecting changes in electromagnetic feedback received in response to the application of the RF energy, wherein the changes occur in response to interaction between the object and acoustic waves; and controlling heating of the object with RF energy in response to the detected changes in the electromagnetic feedback.
  • the electromagnetic feedback may comprise network parameters or values derivable from the network parameters.
  • the changes may occur in response to changes of frequency of acoustic waves interacting with the object.
  • the acoustic waves at least partially penetrate the object.
  • controlling heating of the object with RF energy may comprise at least one of: controlling a power level at which the RF energy is applied to the object; selecting one or more modulation space elements (MSEs) at which the RF energy is applied to the object; and controlling transmission time at which the RF energy is applied at one or more MSEs.
  • MSEs modulation space elements
  • the method may further include generating the acoustic waves.
  • generating the acoustic waves may comprise applying RF waves modulated with a signal having a frequency within an acoustic frequency range.
  • the changes in the electromagnetic feedback may include changes caused by excitation of an acoustic resonance in the object.
  • the object may include plasma.
  • the plasma may be in a plasma lamp.
  • Some embodiments may involve an apparatus for heating an object.
  • the apparatus may comprising: an RF heater configured to heat the object with RF energy; and at least one processor configured to: detect changes in one or more electrical characteristics associated with the object, wherein the changes occur in response to interaction between the object and acoustic waves; and control heating of the object via the RF heater in response to the detected changes in the one or more electrical characteristics associated with the object.
  • the electrical characteristics may comprise network parameters or values derivable from the network parameters.
  • the changes may occur in response to changes of frequency of acoustic waves interacting with the object.
  • the acoustic waves may at least partially penetrate the object.
  • the at least one processor may be configured to control heating of the object with RF energy by at least one of: controlling power level at which the RF energy is applied to the object; selecting one or more modulation space elements (MSEs) at which the RF energy is applied to the object; and controlling transmission time for which the RF energy is applied at one or more MSEs.
  • MSEs modulation space elements
  • the apparatus may further comprise an acoustic transducer configured to generate the acoustic waves.
  • the acoustic generator may comprise an RF source and a modulator configured to modulate an RF wave generated by the RF source with a signal having a frequency within an acoustic frequency range.
  • the at least one processor may be configured to detect excitation of an acoustic resonance in the object, and control the RF heater based on acoustic frequencies at which the acoustic resonances are detected.
  • Some embodiments may involve a method of heating an object.
  • the method may comprise: heating the object with RF energy; receiving a signal indicative of sound velocity inside the object; causing application of RF energy to heat the object when the signal indicates a sound velocity inside the object of less than a first predetermined threshold; causing a reduction in an amount of RF energy applied to the object when the signal indicates a sound velocity inside the object of greater than a second predetermined threshold; and causing an amount of RF energy applied to the object to be maintained over at least some time duration when the signal indicates a sound velocity inside the object that falls between the first and second predetermined thresholds.
  • causing application of RF energy may comprise at least one of: controlling a power level at which the RF energy is applied to the object; selecting one or more modulation space elements (MSEs) at which the RF energy is applied to the object; and controlling transmission time for which the RF energy is applied at one or more MSEs.
  • the method may further comprise generating the signal indicative of sound velocity inside the object, said generating comprising modulating an RF signal with a modulating signal having a frequency at the acoustic range.
  • the method may further comprise: modulating a plurality of RF signals having a common frequency with a plurality of modulating signals having differing frequencies at the acoustic range to generate modulated RF signals, applying the modulated RF signals to the object, and generating the signal indicative of sound velocity inside the object based on electromagnetic feedback received in response to the application of the modulated RF signals.
  • the signal indicative of sound velocity inside the object may be generated when a fluid flows within the object.
  • the object may include a diesel particulate filter (DPF).
  • the object may include plasma.
  • the method may comprise generating the signal indicative of sound velocity inside the object by transmitting a sound wave through the object.
  • Some embodiments may involve an apparatus for heating an object.
  • the apparatus may comprise: an RF heater for heating the object with RF energy; and at least one processor configured to: receive a signal indicative of sound velocity inside the object; cause the RF heater to apply RF eenrgy to the object when the signal indicates a sound velocity inside the object of less than a first predetermined threshold; cause the RF heater to reduce an amount of RF energy applied to the object when the signal indicates a sound velocity inside the object of greater than a second predetermined threshold; and cause the RF heater to maintain an amount of RF energy applied to the object over at least some time duration when the signal indicates a sound velocity inside the object that falls between the first and second predetermined thresholds.
  • the temperature of the object may be above 250°C.
  • the at least one processor may be configured to control at least one of: a power level at which RF energy is applied to the object; one or more modulation space elements (MSEs) at which RF energy is applied to the object; transmission time for which the RF energy is applied at one or more MSEs; or a cooler configured to cool the object.
  • the object may include a diesel particulate filter (DPF).
  • the object may include plasma.
  • the apparatus may further comprise one or more acoustic generators configured to generate an acoustic signal in the object.
  • the RF heater may be configured to generate an RF signal and at least one of the one or more acoustic generators comprises a modulator configured to modulate the RF signal generated by the RF heater with a modulating signal having a frequency at the acoustic range.
  • the at least one processor may be configured to: control the modulator to modulate a plurality of RF signals having a common frequency with a plurality of modulating signals having differing frequencies within the acoustic range to generate modulated RF signals; control the RF heater to apply the modulated RF signals to the object; and generate the signal indicative of sound velocity inside the object based on electromagnetic feedback received in response to the application of the modulated RF signals.
  • at least one of the one or more acoustic generators may comprise a piezoelectric crystal configured to transmit a sound wave through the object.
  • the apparatus may comprise two acoustic generators that transmit acoustic signals at different directions through the object.
  • the apparatus may further comprise an acoustic receiver.
  • the apparatus may further comprise at least one of: a cooler and one or more radiating elements configured to apply RF energy.
  • Some embodiments of the invention may include a method of processing an object.
  • the method may include: applying RF energy to the object; detecting changes in electromagnetic feedback received in response to the application of the RF energy; and controlling object processing in response to the detected changes in the electromagnetic feedback.
  • the changes in electromagnetic feedback may occur in response to interaction between the object and acoustic waves.
  • the processing of the object may include heating, e.g., radio frequency (RF) heating.
  • RF radio frequency
  • Some embodiments of the invention may include an apparatus for processing an object.
  • the apparatus may include: an RF source configured to apply RF energy to the object; and at least one processor configured to: detect changes in one or more electrical characteristics associated with the object, and control object processing in response to the detected changes in the one or more electrical characteristics associated with the object.
  • the changes in the one or more electrical characteristics associated with the object may occur in response to interaction between the object and sound waves.
  • An exemplary embodiment of the invention may include an apparatus for applying RF energy to an object in an energy application zone.
  • the apparatus may include: a first sensor configured to detect a signal related to a sound velocity in the object; and at least one processor configured to determine a temperature of the object based on the detected signal.
  • the at least one sensor is located outside the energy application zone.
  • the apparatus also includes at least one radiating element configured to apply RF energy to the energy application zone.
  • the apparatus may control RF energy application based on or responsive to the signal related to a sound velocity in the object.
  • the first sensor comprises at least one ultrasound transducer and at least one ultrasound detector.
  • the ultrasound transducer and the ultrasound detector are facing each other.
  • the apparatus further comprises a second sensor, configured to detect a second signal related to the sound velocity in the object, wherein the first and second sensors are configured to detect signals related to sound velocity in the object at different directions. In some embodiments, the different directions are opposite to each other.
  • the processor is further configured to determine a velocity of fluids or gases passing through the object in the energy application zone. In some embodiments, the temperature of the object is above 250°C.
  • an apparatus for applying RF energy to an object in an energy application zone via at least one radiating element may be configured to apply RF energy to the energy application zone.
  • the apparatus may include: at least a first sensor configured to detect a signal related to sound velocity in the object during the RF energy application; and a processor configured to control RF energy application via the at least one radiating element based on the detected signal.
  • the at least the first sensor is located outside the energy application zone.
  • the sensor comprises at least one ultrasound transducer and at least one ultrasound detector.
  • the ultrasound transducer and the ultrasound detector face each other.
  • the processor is further configured to control the RF energy application based on information related to the object.
  • the processor is configured to select at least one Modulation Space Element (MSE) at which the at least one radiating element applies RF energy to the energy application zone.
  • the processor is further configured to associate the detected signal with an MSE at which RF energy was applied during the detection of the signal.
  • MSE Modulation Space Element
  • the processor is further configured to cause the application of RF energy at a plurality of MSEs and to associate each MSE with the signals related to sound velocity detected during the application of a particular MSE. In some embodiments, the processor is further configured to: select a subset of MSEs from the plurality of MSEs; and assign different amount of energies to different MSEs in the subset based on the signal associated with each MSE. In some embodiments, the energy application zone is configured to be entirely filled with the object. In some embodiments, the object substantially fills the entire energy application zone.
  • An aspect of some embodiments of the invention may include a method for measuring temperature inside an object located in an energy application zone.
  • the method may include: detecting from at least one US (ultrasound) sensor a first signal related to a sound velocity in the object during RF energy application to the energy application zone; and determining the temperature of the object based on the detected signal.
  • US ultrasound
  • detecting the signal related to the sound velocity may include: sending an ultrasound signal to the energy application zone; receiving the signal after the signal has traveled through the object; and measuring a time interval between sending and receiving of the signal.
  • sending the ultrasound signal to the energy application zone is from outside of the energy application zone.
  • receiving the signal after the signal has traveled through the object may include receiving from outside of the energy application zone.
  • the temperature of the object is above 250°C.
  • the method may further include detecting a second sound signal related to a velocity.
  • detecting the first signal related to a sound velocity is from a first direction
  • detecting the second signal related to a sound velocity is from a second direction different from the first direction.
  • the method may further include determining a velocity of a fluid passing through the energy application zone based on the first and the second signals related to the sound velocities.
  • the energy application zone is configured to be filled by the object. In some embodiments, the object substantially entirely fills the energy application zone.
  • An aspect of some embodiments of the invention may include a method for applying RF energy to process an object in an energy application zone.
  • the method may include:
  • detecting the signal related to a sound velocity includes: sending an ultrasound signal to pass through the object in the energy application zone; receiving the ultrasound signal after the signal passes through the object; and measuring the time interval between sending and receiving the signal.
  • sending is from outside of the energy application zone.
  • receiving is from outside of the energy application zone.
  • the temperature of the object is above 250°C.
  • the method may further include controlling the RF energy application based on information related to the object.
  • controlling the RF energy application includes selecting at least one MSE in which the energy is to be applied.
  • the method may further include associating the measured signal related to the sound velocity with the MSE at which RF energy was applied during the measurements of the signal. In some embodiments, the method may further include: applying RF energy at a plurality of MSEs; detecting the signal related to the sound velocity in the object during the application of RF energy at each of the plurality of MSEs; and associating each of the plurality of MSEs with the signal measured when RF energy was applied at that MSE.
  • controlling the RF energy application may include: selecting at least a subset of MSEs from the plurality of MSEs based on the signal related to the sound velocity; and assigning different amount of energies to different MSEs from the subset of MSEs based on the signal associated with each MSE.
  • the energy application zone is configured to be entirely filled with the object. In some embodiments, the object substantially fills the energy application zone.
  • Some exemplary aspects of the invention may be directed to a method for measuring temperature inside an object located in an energy application zone.
  • the method may comprise detecting a first signal related of the sound velocity in the object during RF energy application to the energy application zone and determining the temperature of the object based on the measured signal.
  • detecting a signal related to a sound velocity may include sending an ultrasound (US) signal to the energy application zone, receiving the signal after traveling through the object and measuring the time interval between sending and receiving the signal.
  • US ultrasound
  • Some apparatuses for applying RF energy to an energy application zone may include one or more sensors configured to detect a signal related to a sound velocity in the object during the RF energy application and at least one processor configured to determine a temperature of the object based on the detected signal.
  • the apparatus may include at least one radiating element configured to apply RF energy to the energy application zone.
  • one or more of the sensors may be located outside the energy application zone.
  • Some other aspects of the invention may be related to controlling RF energy application to an energy application zone based on detection of a signal related to sound velocity in an object placed in the energy application zone.
  • the signal related to sound velocity may be sent and received during the RF energy application to the zone.
  • FIG. 1 is a diagrammatic representation of an apparatus for applying electromagnetic energy to an object, in accordance with some exemplary embodiments of the present invention
  • FIG. 2A is a view of a cavity, in accordance with some exemplary embodiments of the present invention.
  • FIG. 2B is a view of a cavity, in accordance with some exemplary embodiments of the present invention.
  • FIG. 3 is a representation of an exemplary modulation space, in accordance with some exemplary embodiments of the present invention.
  • FIG. 4 is a diagrammatic representation of an apparatus for applying electromagnetic energy to an object, in accordance with some exemplary embodiments of the present invention.
  • FIG. 5 is a flow chart of a method for applying electromagnetic energy to an energy application zone, in accordance with some embodiments of the present invention.
  • Fig. 6 is a diagrammatic representation of an apparatus for applying RF energy to an object, in accordance with some aspects of the invention.
  • Fig. 7 is a diagrammatic representation of an apparatus for applying RF energy and measuring the temperature of a filter in a emission reduction device, in accordance with some embodiments of the present invention;
  • Fig. 8 is a flowchart of a method for measuring the temperature of an object, in accordance with some embodiments of the present invention.
  • Fig. 9 is a flow chart of a method of heating an object according to some embodiments of the invention.
  • Fig. 10 is diagrammatic illustration of some waveforms that may be utilized in some embodiments of the invention.
  • Fig. 1 1 is s a flowchart of method of identifying an acoustic resonance in an object according to some embodiments of the invention
  • Fig. 12 is a diagrammatic illustration of an apparatus for heating an object by RF energy according to some embodiments of the invention.
  • FIG. 13 is diagrammatic illustration of a processor according to some embodiments of the invention.
  • Fig. 14 is a flow chart of a method of heating an object according to some embodiments of the invention.
  • Some aspects of the invention may relate to methods for measuring a temperature of an object placed in an energy application zone. Some embodiments may relate to methods of controlling RF (radio frequency) energy application to an energy application zone based on acoustic signals.
  • the energy application zone may include any void, location, region, or area where electromagnetic energy may be applied.
  • an energy application zone may be at least partially inside or may include at least a part of a cooking oven, a filter (e.g., a Diesel Particulate Filter, also referred to as a DPF), a burner in a gas turbine, a chemical reactor, a furnace, a combustion chamber, a plasma lamp, etc.
  • a filter e.g., a Diesel Particulate Filter, also referred to as a DPF
  • RF energy may be applied to process the object (e.g., cook the food, regenerate the filter, ignite the lamp, etc.) via at least one radiating element (e.g., an antenna).
  • the object may substantially fill the volume of the energy application zone.
  • the object may include a filter in an emission reduction device, a chemical solution in a plug flow reactor, a soup in a pot, etc.
  • the object may fill the energy application zone only partially.
  • the object may include a pizza in a baking oven, a polymer part in a curing furnace, a plasma lamp in a metal mesh cavity, etc.
  • An energy application zone may be defined by walls, e.g., metallic walls that define a cavity.
  • the cavity may be a resonant cavity, also referred to as a resonator.
  • the walls may be made of metallic mesh, allowing light to escape the energy application zone but confining RF energy within the zone.
  • RF energy application may be controlled, or otherwise adjusted, based on temperature measurement.
  • the temperature measurement may include detecting a signal indicative of or related to sound velocity in the object.
  • Embodiments of the invention may operate using sound waves of any suitable frequency, for example, ultrasonic, sonic, and/or infrasonic frequencies.
  • sound, ultrasound, and acoustic may be used through the present disclosure interchangeably.
  • Physical phenomenon such as the temperature dependence of sound velocity in an object, for example, in fluids included in the object, may be used to infer temperature based on detection and interpretation of the sound velocity within the object.
  • a signal related to the sound velocity may include any detectable or measurable signal that may be related to the velocity of sound waves that propagate in an object or a medium.
  • a signal related to the sound velocity may include any signal that may be detected by a sensor and is indicative of, for example, the sound velocity and/or a time period, during which a sound wave travels through a known distance inside the object or the energy application zone.
  • the time period may include a time duration during which a sound wave generated by an ultrasonic (US) transducer reaches a US detector.
  • a signal related to sound velocity in an object may include a signal indicative of an acoustic resonance in the object or in an energy application zone enclosing the object.
  • the acoustic resonance may be detected by sweeping over a plurality of acoustic frequencies and identifying a frequency at which the energy application zone or the object resonates. Alternatively or additionally, transmission of a broad band acoustic signal may be used for detecting the resonance.
  • the resonance may be detected by monitoring an electromagnetic response of the energy application zone in response to RF energy application.
  • the electromagnetic response may be a function of the frequency of the acoustic wave.
  • the electromagnetic response may be monitored, for example, by monitoring what portion of the electromagnetic power applied to the energy application zone is absorbed therein; how the phase of an electromagnetic wave entering the energy application zone through one radiating element changes when the electromagnetic wave is received at another radiating element, etc.
  • Such response may be expressed in terms of network parameters of the energy application zone.
  • the response may also include changes of network parameters of the energy application zone.
  • the changes may include a first order derivative of one or more network parameters as different acoustic waves having different frequencies interact with the object in the energy application zone.
  • the changes may include differences between one or more network parameters.
  • the changes may also be compared with one or more thresholds to determined how large the changes are and/or how rapidly the changes occur.
  • a large change of the network parameter caused by a small change in the acoustic frequency at which the network parameter is measured may indicate that an acoustic resonance occurs in the energy application zone.
  • the signals related to the sound velocity may be associated with temperatures of the object.
  • the association or relationship between the signals related to the sound velocity and the temperatures of the object may be stored in a lookup table in a controller or a processor associated with the energy application zone and/or the radiating element.
  • detected signals related to the sound velocity may be compared with the data stored in the lookup table to determine corresponding temperatures.
  • different data may be stored for different objects.
  • the lookup table may indicate the temperature of the object based on the detected signal.
  • RF energy application may be controlled based on the temperature.
  • RF energy application may be controlled based on the detected signal.
  • a lookup table may associate signals related to sound velocity with control signals for controlling an RF heater. Thus, calculating the temperature may be omitted. The temperature (or a signal indicative thereof), however, may still be utilized for controlling RF energy application.
  • RF energy may be applied to process an object in the energy application zone. Processing an object may include applying RF energy to the object, for example, to heat the object. Some aspects of the invention may be related to determining the temperature of an object in the energy application zone during the RF energy application process.
  • RF energy application may involve emitting RF radiation.
  • temperature measurement does not affect the RF radiation or the electromagnetic field excited in the energy application zone.
  • temperature measurement may be based upon interaction between acoustic waves and RF field.
  • low power RF may be used for temperature measurement, so as not to interfere with the heating or to minimize interference with heating.
  • low power acoustics may be used for temperature measurement, so as not to interfere with the heating or to minimize interference with heating.
  • Detecting a signal related to the sound velocity of the traveling acoustic (e.g., ultrasonic) waves in the presence of the object may allow determination of the temperature inside the object.
  • the signal related to the sound velocity may be received or detected by a sensor during the RF energy application process, without interacting with the RF energy.
  • temperature may be determined in real time or in situ during the RF energy application process.
  • RF energy application at low power may take place to adjust RF energy application parameters including, for example, power levels, transmitted frequencies, transmission time etc.
  • RF energy application at low power may also take place to measure an acoustic response of the object and/or the energy application zone to determine additional parameters, based on which RF energy application may be adjusted.
  • the temperature inside the object may be measured from outside of the energy application zone.
  • Acoustic sensors e.g., ultrasonic sensors may be installed outside the energy application zone. Installing the sensors outside the energy application zone may be beneficial, for example, in an emission reduction device (e.g., a DPF) or in any other embodiment where it may be impractical or undesirable to incorporate the sensor into the energy application zone.
  • Such embodiments may include, for example, embodiments where the object substantially fills the energy application zone, or where the energy application zone should remain free of foreign object, or when the energy application zone is to accommodate flowing medium such that the sensors might interfere with the flowing medium.
  • Sensors attached to the outer surface of an emission reduction device may detect the signal related to the sound velocity in a filter located inside the emission reduction device, as illustrated for example in Fig. 7.
  • acoustic sensors e.g., ultrasound velocity sensors
  • Installing the sensors inside the energy application zone, e.g., in proximity to the object, may be beneficial when the object only partially fills the energy application zone.
  • the sensors may be installed in proximity to or attached to the object in order to detect the signal related to the sound velocity in the object.
  • the signal related to the sound velocity may be detected using at least one sensor.
  • the at least one sensor may be configured to measure a time period, during which sound travels a known distance inside the object.
  • the object may substantially fill the volume of the energy application zone (e.g., a chemical solution in a plug flow reactor), and sound travelling in the energy application zone may travel through a single medium only (e.g., the object).
  • the object may fill only a portion of the energy application zone (e.g., a food item in a cooking oven), and the sound travelling through the energy application zone may pass via at least two media: the object and the environment around the object (e.g., the food item and the air in the oven).
  • the sound sensor may include at least one acoustic transducer
  • acoustic detector configured to detect acoustic waves.
  • Ultrasonic sensors may work on a principle similar to sonar which evaluates attributes of a target by interpreting sound wave echoes reflecting from the target. Some sensors may be configured to measure the time interval between sending of a signal and receiving the echo to determine the distance between the sensor and the object or the sound velocity in the medium separating the sensor from the object.
  • An acoustic transducer is a device that converts energy into acoustic signals.
  • the transducer may include piezoelectric transducers that convert electrical energy into acoustic signals in the sonic, ultrasonic, and/or infrasonic range. Piezoelectric crystals have the property of changing size when a voltage is applied.
  • Ultrasound detectors may include devices configured to generate an electromagnetic signal, for example a voltage, when detecting sound waves.
  • piezoelectric crystals generate a voltage when a force or pressure is applied to them. Since piezoelectric crystals may act as both transducers and detectors, the same crystal can be used as an ultrasonic detector and transducer. In other words, a single piezoelectric crystal device can be used both as an acoustic transducer and as an acoustic detector.
  • a sensor that can act as both a transducer and a detector may also be called a transceiver.
  • Receiving acoustic waves or waveforms may be performed in several ways.
  • the transducer may perform both the functions of sending pulsed acoustic waves and receiving echoes when the acoustic waves are reflected back to the transducer.
  • Reflection of ultrasonic waves may occur at an interface where the acoustic properties change, such as an outer surface of the object or an imperfection within the object.
  • the received echo signal may include information about the intensity of the reflection (e.g., inferred from the amplitude of the signal) and information about the distance between the transducer and the reflection interface (e.g., inferred from time of arrival of the echo signal).
  • a transmitter e.g., a transducer
  • a separate receiver e.g., another transducer
  • the sound velocity C in an object located in a non-flowing environment may be represented by the following equation (A):
  • L 12 is the sound path length in the object between point 1 and point 2
  • ti 2 is the time duration, during which the sound travels between point 1 and point 2.
  • the transducer is located in point 1 and the detector is located in point 2 (or vice versa).
  • a flowing environment may be defined as a flowing fluid that surrounds and/or passes through an object placed in an energy application zone.
  • a fluid velocity v e.g., a soot filter inside a DPF where the exhaust gasses are flowing from the engine through the DPF at velocity v
  • a second sound detection may be needed.
  • traveling time of the sound waves may be represented by the following two equations (B and C):
  • ⁇ is the angle between the sound wave propagating direction and the fluid velocity direction (see Fig. 7)
  • t 1 ⁇ 2 is the time required for the sound wave to travel from the transducer located at point 1 to the detector located at point 2
  • t 2 ⁇ i is the time required for the sound wave to travel from the transducer located at point 2 to the detector located at point 1.
  • the sound velocities C and C* may depend on the temperature of the object through which the sound wave is traveling.
  • the sound velocity may increase when the temperature rises.
  • the signal related to the sound velocity may be measured for a known object having known dimensions (e.g., a soot filter, a plasma lamp, or a Pizza) at various temperatures. The temperature during the measurements may be sensed by thermometers, for example,
  • thermocouples The data gathered during those measurements may be stored in a lookup table associating sound velocities with temperatures of a particular object.
  • the particular object or a similar object may be heated to a particular temperature, and the sound velocity may be measured.
  • a reference object may be considered similar to the particular object if the two objects have similar density and bulk modulus, which may lead to a similar relationship between sound velocity and temperature.
  • all aqueous solutions may be considered similar to each other; all yeast-based dough portions may be considered similar to each other, etc.
  • a sound velocity of an acoustic (e.g., ultrasound) wave traveling through the particular object may be detected, e.g., several times at several different temperatures, during an RF energy application process.
  • the temperature of the object may be determined as the RF energy application progresses (e.g., by comparing the detected sound velocities with values stored in a look up table).
  • RF energy application may be controlled to increase heating if the temperature approaches the lower limit and to reduce heating if the temperature approaches the upper limit.
  • coolers may also be operated to cool faster or slower based on the measured temperature.
  • temperature calculation may be omitted, and the lookup table may associate control signals of the RF heater and/or coolers directly with the detected signals indicative of the sound velocity within the object.
  • the invention may involve apparatus and methods for applying electromagnetic energy.
  • electromagnetic energy includes energy deliverable by electromagnetic radiation in all or portions of the electromagnetic spectrum, including but not limited to, radio frequency (RF), infrared (IR), near infrared, visible light, ultraviolet, etc.
  • applied electromagnetic energy may include RF energy with a wavelength in free space of 100 km to 1 mm, which corresponds to a frequency of 3 KHz to 300 GHz, respectively.
  • the applied electromagnetic energy may fall within frequency bands between 500 MHz to 1500 MHz or between 700 MHz to 1200 MHz or between 800 MHz - 1 GHz. Applying energy in the RF portion of the
  • electromagnetic spectrum is referred herein as applying RF energy.
  • Microwave and ultra high frequency (UHF) energy are both within the RF range.
  • the applied electromagnetic energy may fall only within one or more ISM frequency bands, for example, between 433.05 and 434.79 MHz, between 902 and 928 MHz, between 2400 and 2500 MHz, and/or between 5725 and 5875 MHz.
  • ISM frequency bands for example, between 433.05 and 434.79 MHz, between 902 and 928 MHz, between 2400 and 2500 MHz, and/or between 5725 and 5875 MHz.
  • the application of electromagnetic energy may occur in an "energy application zone,” such as energy application zone 9, as shown in Fig. 1.
  • Energy application zone 9 may include any void, location, region, or area where electromagnetic energy may be applied. It may be hollow, or may be filled or partially filled with liquids, solids, gases, or combinations thereof.
  • energy application zone 9 may include an interior of an enclosure, interior of a partial enclosure, open space, solid, or partial solid that allows existence, propagation, and/or resonance of electromagnetic waves.
  • Zone 9 may include a conveyor belt or a rotating plate.
  • all such energy application zones may alternatively be referred to as cavities. It is to be understood that an object is considered “in” the energy application zone if at least a portion of the object is located in the zone or if some portion of the object receives delivered electromagnetic radiation.
  • an apparatus or method may involve the use of at least one source (e.g., RF energy source) configured to deliver RF energy.
  • RF energy source e.g., RF energy source
  • a “source” may include any
  • electromagnetic energy may be delivered to the energy application zone in the form of propagating electromagnetic waves at predetermined
  • Electromagnetic radiation carries energy that may be imparted to (or dissipated into) matter with which it interacts.
  • a machine e.g., a processor
  • a task e.g., configured to cause application of a predetermined field pattern
  • the machine performs this task during operation.
  • a target result e.g., in order to apply a plurality of electromagnetic field patterns to the object
  • electromagnetic energy may be applied to an object 1 1.
  • references to an "object” to which electromagnetic energy is applied is not limited to a particular form.
  • An object may include a liquid, semi-liquid, solid, semi-solid, or gas, depending upon the particular process with which the invention is utilized.
  • the object may also include composites or mixtures of matter in differing phases.
  • the term "object” encompasses such matter as food to be defrosted or cooked; clothes or other wet material to be dried; frozen organs to be thawed; chemicals to be reacted; fuel or other combustible material to be combusted; hydrated material to be dehydrated, gases to be expanded; liquids to be heated, boiled or vaporized, filters to be regenerated, gas flames to be stabilized or anchored, or any other material for which there is a desire to apply, even nominally, electromagnetic energy.
  • object 1 1 may constitute at least a portion of a load.
  • a portion of electromagnetic energy supplied to energy application zone 9 may be absorbed by object 1 1.
  • another portion of the electromagnetic energy supplied or delivered to energy application zone 9 may be absorbed by various elements (e.g., food residue, particle residue, additional objects, structures associated with zone 9, or any other electromagnetic energy-absorbing materials found in zone 9) associated with energy application zone 9.
  • Energy application zone 9 may also include loss constituents that do not, themselves, absorb an appreciable amount of electromagnetic energy, but otherwise account for
  • a load may include at least a portion of object 1 1 along with any
  • electromagnetic energy-absorbing constituents in the energy application zone as well as any electromagnetic energy loss constituents associated with the zone.
  • FIG. 1 is a diagrammatic representation of an apparatus 100 for applying
  • Apparatus 100 may include a controller 101, an array 102a of radiating elements 102 (e.g. antennas) including one or more radiating elements, and energy application zone 9. Controller 101 may be electrically coupled to one or more radiating elements 102. As used herein, the term “electrically coupled” refers to one or more either direct or indirect electrical connections. Controller 101 may include a computing subsystem 92, an interface 130, and an electromagnetic energy application subsystem 96. Based on an output of computing subsystem 92, energy application subsystem 96 may respond by generating one or more radio frequency signals to be supplied to antennas 102. In turn, the one or more radiating elements 102 may radiate electromagnetic energy into energy application zone 9. In certain embodiments, this energy can interact with object 11 positioned within energy application zone 9.
  • this energy can interact with object 11 positioned within energy application zone 9.
  • computing subsystem 92 may include a general purpose or special purpose computer. Computing subsystem 92 may be configured to generate control signals for controlling electromagnetic energy application subsystem 96 via interface 130. Computing subsystem 92 may further receive measured signals from
  • electromagnetic energy application subsystem 96 via interface 130.
  • controller 101 is illustrated for exemplary purposes as having three
  • control functions may be consolidated in fewer components, or additional components may be included consistent with the desired function and/or design of a particular embodiment.
  • Exemplary energy application zone 9 may include locations where energy is applied in an oven, chamber, tank, dryer, thawer, dehydrator, reactor, engine, chemical or biological processing apparatus, furnace, filter (e.g., DPF), burner in gas turbine, incinerator, material shaping or forming apparatus, conveyor, combustion zone, cooler, freezer, etc.
  • the energy application zone may be part of a vending machine, in which objects are processed once purchased.
  • energy application zone 9 may include an electromagnetic resonator 10 (also known as cavity resonator, or cavity) (illustrated for example in Fig. 2A).
  • energy application zone 9 may be congruent with the object or a portion of the object (e.g., the object or a portion thereof is or may define the energy application zone).
  • Fig. 2A shows a sectional view of a cavity 10, which is one exemplary embodiment of energy application zone 9.
  • Cavity 10 may be cylindrical in shape (or any other suitable shape, such as semi-cylindrical, rectangular, elliptical, cuboid, symmetrical, asymmetrical, irregular, regular, etc.) and may be made of a conductor, such as aluminum, stainless steel or any suitable metal or other conductive material.
  • cavity 10 may include walls coated and/or covered with a protective coating, for example, made from materials transparent to EM energy, e.g., metallic oxides or others.
  • cavity 10 may have a spherical shape or hemispherical shape (for example as illustrated in Fig.
  • Cavity 10 may be resonant in a predetermined range of frequencies (e.g., within the UHF or microwave range of frequencies, such as between 300 MHz and 3 GHz, or between 400 MHz and 1 GHZ). It is also contemplated that cavity 10 may be closed, e.g., completely enclosed (e.g., by conductor materials), bounded at least partially, or open, e.g., having non-bounded openings.
  • the general methodology of the invention is not limited to any particular cavity shape or configuration, as discussed earlier.
  • Fig. 2A shows a sensor 20 and antennas 16 and 18 (examples of radiating elements 102 shown in Fig. 1).
  • Fig. 2B shows a top sectional view of a cavity 200 according to another exemplary embodiment of energy application zone 9.
  • Fig. 2B shows antennas 210 and 220 (as examples of radiating elements 102 shown in Fig. 1).
  • Cavity 200 comprises a space 230 for receiving object 11 (not shown).
  • Space 230 as shown between the dotted lines in Fig. 2B, has an essentially rectangular cross section, which may be adapted for receiving a tray on top of which object 11 may be placed.
  • field adjusting element(s) may be provided in energy application zone 9, for example, in cavity 10 and/or cavity 200.
  • Field adjusting element(s) may be adjusted to change the electromagnetic wave pattern in the cavity in a way that selectively directs the electromagnetic energy from one or more of antennas 16 and 18 (or 210 and 220) into object 1 1.
  • field adjusting element(s) may be further adjusted to simultaneously match at least one of the antennas that act as transmitters, and thus reducing coupling to the other antennas that act as receivers.
  • one or more sensor(s) (or detector(s)) 20 may be used to sense (or detect) information (e.g., signals) relating to object 11 and/or to the energy application process and/or the energy application zone.
  • one or more antennas e.g., antenna 16, 18, 210 or 220, may be used as sensors.
  • the sensors may be used to sense any information, including electromagnetic power, temperature, weight, humidity, motion, etc.
  • ultrasound sensors may be installed inside or outside of the energy application zone. The sensed information may be used for any purpose, including RF energy application control, process verification, automation, authentication, safety, etc.
  • Automation may be affected, for example, by adjusting heating parameters in accordance with a feedback on the processed object received by the sensor(s). For example, stopping or adjusting the processing, e.g., heating, once the sensor(s) indicate that certain stopping or adjusting criteria are met, for example, once sufficient amount of energy is absorbed in the object, once one or more portions of the object are at a predetermined temperature, once time derivatives of absorbed power changes.
  • the sensed information may be used to control the RF energy application to zone 9.
  • ultrasound sensors may detect a signal related to sound velocity in object 1 1, determine the temperature of object 1 1 according to the sound velocity, and control the RF energy application according to the determined temperature.
  • the RF energy application may be terminated when the object reaches a certain higher temperature limit and restarted when the temperature reaches a certain lower temperature limit.
  • Such automatic processing adjustment or stoppage may be useful, for instance, in vending machines, where food products are kept cool or at room temperature, and heated or cooked only when purchased. Purchase may start the heating, and specific heating conditions (for example, energy supplied at each MSE) are determined in accordance with feedback from the heated product. Additionally or alternatively, heating is stopped once the sensors sense conditions that are defined to the controller as stopping criteria. Additionally or alternatively, cooking or processing instructions may be provided on a machine readable element, e.g., a barcode or a tag, associated with the processed object, e.g., heated food product that has been purchased in the vending machine.
  • a machine readable element e.g., a barcode or a tag
  • more than one feed and/or a plurality of radiating elements may be provided.
  • the radiating elements may be located on one or more surfaces of, e.g., an enclosure defining the energy application zone. Alternatively, radiating elements may be located inside or outside the energy application zone. One or more of the radiating elements may be close to, in contact with, in the vicinity of, or even embedded in object 11 (e.g., when the object is a liquid).
  • the orientation and/or configuration of each radiating element may be different or the same, based on the specific application, e.g., based on a desired target effect.
  • Each radiating element may be positioned, adjusted, and/or oriented to transmit electromagnetic waves along a same direction, or various different directions. Furthermore, the location, orientation, and configuration of each radiating element may be predetermined before applying energy to the object. Alternatively or additionally, the location, orientation, and configuration of each radiating element may be dynamically adjusted, for example, by using a processor, during operation of the apparatus and/or between rounds of energy application.
  • the invention is not limited to radiating elements having particular structures or locations within the apparatus.
  • apparatus 100 may include at least one radiating element 102 in the form of at least one antenna for delivery of electromagnetic energy to energy application zone 9.
  • One or more of the antenna(s) may also be configured to receive electromagnetic energy from energy application zone 9.
  • radiating element as used herein may function as a transmitter, a receiver, or both, depending on a particular application and configuration.
  • a radiating element acts as a receiver of electromagnetic energy (e.g., reflected electromagnetic waves)
  • the radiating element receives electromagnetic energy from the energy application zone.
  • a radiating element and “antenna” may broadly refer to any structure from which electromagnetic energy may radiate and/or be received, regardless of whether the structure was originally designed for the purposes of radiating or receiving energy, and regardless of whether the structure serves any additional function.
  • a radiating element or an antenna may include an aperture/slot antenna, or an antenna which includes a plurality of terminals transmitting in unison, either at the same time or at a controlled dynamic phase difference (e.g., a phased array antenna).
  • radiating elements 102 may include an electromagnetic energy transmitter (referred to herein as “a transmitting antenna”) that feeds energy into electromagnetic energy application zone 9, an electromagnetic energy receiver (referred herein as “a receiving antenna") that receives energy from zone 9, or a combination of both a transmitter and a receiver.
  • a first antenna may be configured to supply electromagnetic energy to zone 9, and a second antenna may be configured to receive energy from the first antenna.
  • one or more antennas may each serve as both receivers and transmitters.
  • one or more antennas may serve dual functions while one or more other antennas may serve a single function.
  • a single antenna may be configured to both deliver electromagnetic energy to the zone 9 and to receive electromagnetic energy from the zone 9.
  • a first antenna may be configured to deliver electromagnetic energy to the zone 9, and a second antenna may be configured to receive electromagnetic energy from the zone 9.
  • a plurality of antennas could be used, where at least one of the plurality of antennas may be configured to both deliver electromagnetic energy to zone 9 and to receive electromagnetic energy from zone 9.
  • an antenna may also be adjusted to affect the field pattern. For example, various properties of the antenna, such as position, location, orientation, temperature, etc., may be adjusted. Different antenna property settings may result in different electromagnetic field patterns within the energy application zone thereby affecting energy absorption in the object. Therefore, antenna adjustments may constitute one or more variables that can be varied for energy application control.
  • energy may be supplied and/or provided to one or more transmitting antennas.
  • Energy supplied to a transmitting antenna may result in energy emitted by the transmitting antenna (referred to herein as "incident energy”).
  • the incident energy may be delivered to zone 9, and may be in an amount equal to an amount of energy supplied to the transmitting antenna(s) by a source (e.g., source 2050 presented in Fig. 4).
  • a portion of the incident energy may be dissipated in the object or absorbed by the object (referred to herein as “dissipated energy” or “absorbed energy”). Another portion may be reflected back to the transmitting antenna (referred to herein as "reflected energy").
  • Reflected energy may include, for example, energy reflected back to the transmitting antenna due to impedance mismatch between the object and the energy application zone. Reflected energy may also include energy retained by the port of the transmitting antenna (e.g., energy that is emitted by the antenna but does not flow into the zone). The rest of the incident energy, other than the reflected energy and dissipated energy, may be coupled to one or more receiving antennas other than the transmitting antenna (referred to herein as "coupled energy.”). Therefore, the incident energy (“I") supplied to the transmitting antenna may include all of the dissipated energy ("D"), reflected energy ("R”), and coupled energy (“T”), and may be expressed according to the following relationship:
  • the one or more transmitting antennas may deliver electromagnetic energy into zone 9.
  • the application of electromagnetic energy may occur via one or more power feeds.
  • a feed may include one or more waveguides and/or one or more radiating elements (e.g., antennas 102) for applying electromagnetic energy to the zone.
  • radiating elements may include, for example, patch antennas, fractal antennas, helix antennas, log-periodic antennas, spiral antennas, slot antennas, dipole antennas, loop antennas, slow wave antennas, leaky wave antennas or any other structures capable of transmitting and/or receiving
  • the invention is not limited to radiating elements having particular structures or locations.
  • Antennas e.g., antenna 102
  • the foregoing are examples only, and polarization may be used for other purposes as well.
  • three antennas may be placed parallel to orthogonal coordinates; however, it is contemplated that any suitable number of antennas (such as one, two, three, four, five, six, seven, eight, etc.) may be used.
  • a higher number of antennas may add flexibility in system design and improve control of energy distribution, e.g., greater uniformity and/or resolution of energy application in zone 9.
  • one or more of radiating elements 102 may be slow wave antenna(s).
  • a slow-wave antenna may refer to a wave-guiding structure that possesses a mechanism that permits it to emit power along all or part of its length.
  • the slow wave antenna may comprise a plurality of slots to enable EM energy to be emitted.
  • the object to be processed e.g., cooked, may be placed in the energy application zone so that a coupling may be formed between an evanescent EM wave (e.g., emitted from a slow wave antenna) and the object.
  • An evanescent EM wave in free space e.g., in the vicinity of the slow wave antenna
  • a coupling between a load (e.g., object) and the evanescent wave emitted from the slow wave antenna such that the wave is resonant in the load may be referred as "load resonance.”
  • the processor e.g., controller 101 in Fig. 1 or processor 2030 in Fig. 4
  • the processor may be configured to choose at least one frequency (which may be referred to as a load resonance frequency) in which the EM energy may be applied to the energy application zone such that a load resonance coupling may be performed.
  • the frequency may be chosen based on feedback signals from the energy application zone as a function of the frequency.
  • feedback signals may include the reflected and transmitted powers, reflected and transfer coefficients, and dissipation ratio (DR).
  • DR dissipation ratio
  • a good resonant coupling in the load may be detected when the feedback from the energy application zone shows high energy absorption peaks or high power absorption peaks at one or more frequencies (e.g., very low DR peak values, or low reflection coefficient
  • the processor may be configured to choose or determine load resonance frequencies based on dielectric properties of the load.
  • the dielectric properties may be detected from the load or may be obtained in any other manner (e.g., by a tag associated with the load or it may be known to the processor before the load was placed in the energy application zone).
  • Radiating elements 102 may be configured to feed energy at specifically chosen modulation space elements, referred to herein as MSEs, which can be chosen by controller 101.
  • modulation space or “MS” is used to collectively refer to all the parameters that may affect a field pattern in the energy application zone and all combinations thereof.
  • the "MS” may include all possible components that may be used and their potential settings (absolute and/or relative to others) and adjustable parameters associated with the components.
  • the "MS” may include a plurality of variable parameters, the number of antennas, their positioning and/or orientation (if modifiable), the useable bandwidth, a set of all useable frequencies and any combinations thereof, power settings, phases, etc.
  • the MS may have any number of possible variable parameters, ranging between one parameter only (e.g., a one dimensional MS limited to frequency only or ghase only— or other single parameter), two or more dimensions (e.g., varying frequency and amplitude or varying frequency and phase together within the same MS), or many more.
  • one parameter only e.g., a one dimensional MS limited to frequency only or ghase only— or other single parameter
  • two or more dimensions e.g., varying frequency and amplitude or varying frequency and phase together within the same MS
  • Each variable parameter associated with the MS is referred to as an MS dimension.
  • Fig. 3 illustrates a three dimensional modulation space (MS) 300, with three dimensions designated as frequency (F), phase (P), and amplitude (A). That is, in MS 300, frequency, phase, and amplitude (e.g., an amplitude difference between two or more waves being transmitted at the same time) of the electromagnetic waves are modulated during energy delivery, while all the other parameters may be fixed during energy delivery.
  • the modulation space is depicted in three dimensions for ease of discussion only.
  • the MS may have any number of dimensions, e.g., one dimension, two dimensions, four dimensions, n dimensions, etc.
  • a one dimensional modulation space oven may provide MSEs that differ one from another only by frequency.
  • MSE modulation space element
  • the MS may also be considered to be a collection of all possible MSEs.
  • two MSEs may differ one from another in the relative amplitudes of the energy being supplied to a plurality of radiating elements.
  • Fig. 3 shows an MSE 301 in the three-dimensional MS 300.
  • MSE 301 has a specific frequency F(i), a specific phase P(i), and a specific amplitude A(i). If even one of these MSE variables changes, then the new set defines another MSE. For example, (3 GHz, 30°, 12 V) and (3 GHz, 60°, 12 V) are two different MSEs, although only the phase component is different.
  • an energy delivery scheme may consist of three MSEs: (F(l), P(l),
  • Such an energy application scheme may result in applying the first, second, and third MSE to the energy application zone.
  • the invention is not limited to any particular number of MSEs or MSE combinations.
  • Various MSE combinations may be used depending on the requirements of a particular application and/or on a desired energy transfer profile, and/or given equipment, e.g., cavity dimensions.
  • the number of options that may be employed could be as few as two or as many as the designer desires, depending on factors such as intended use, level of desired control, hardware or software resolution and cost.
  • processors may include an electric circuit that performs a logic operation on input or inputs.
  • a processor may include one or more integrated circuits, microchips, microcontrollers, microprocessors, all or part of a central processing unit (CPU), graphics processing unit (GPU), digital signal processors (DSP), field-programmable gate array (FPGA) or other circuit suitable for executing instructions or performing logic operations.
  • the at least one processor may be coincident with or may be part of controller 101.
  • the instructions executed by the processor may, for example, be pre-loaded into the processor or may be stored in a separate memory unit such as a RAM, a ROM, a hard disk, an optical disk, a magnetic medium, a flash memory, other permanent, fixed, or volatile memory, or any other mechanism capable of storing instructions for the processor.
  • the processor(s) may be customized for a particular use, or can be configured for general-purpose use and can perform different functions by executing different software.
  • the at least one processor may be configured to cause electromagnetic energy to be applied to zone 9 via one or more antennas, for example across a series of MSEs, in order to apply electromagnetic energy at each such MSE to an object 1 1.
  • the at least one processor may be configured to regulate one or more components of controller 101 in order to cause the energy to be applied.
  • the at least one processor may be configured to determine a value indicative of energy absorbable by the object at each of a plurality of MSEs. This may occur, for example, using one or more lookup tables, by pre-programming the processor or memory associated with the processor, and/or by testing an object in an energy application zone to determine its absorbable energy characteristics.
  • One exemplary way to conduct such a test is through a sweep.
  • a sweep may include, for example, the transmission over time of energy at more than one MSE.
  • a sweep may include the sequential transmission of energy at multiple MSEs in one or more contiguous MSE band; the sequential transmission of energy at multiple MSEs in more than one non-contiguous MSE band; the sequential transmission of energy at individual non-contiguous MSEs; and/or the transmission of synthesized pulses having a desired MSE/power spectral content (e.g., a synthesized pulse in time).
  • the MSE bands may be contiguous or non-contiguous.
  • the at least one processor may regulate the energy supplied to the at least one antenna to sequentially deliver electromagnetic energy at various MSEs to zone 9, and to receive feedback which serves as an indicator of the energy absorbable by object 11. While the invention is not limited to any particular measure of feedback indicative of energy absorbable in the object, various exemplary indicative values are discussed below.
  • electromagnetic energy application subsystem 96 may be regulated to receive electromagnetic energy reflected and/or coupled at antenna(s) 102, and to communicate the measured energy information (e.g., information pertaining to and/or related to and/or associated with the measured energy) back to computing subsystem 92 via interface 130, as illustrated in Fig. 1.
  • Computing subsystem 92 may then be regulated to determine a value indicative of energy absorbable by object 1 1 at each of a plurality of MSEs based on the received information.
  • a value indicative of the absorbable energy may include a dissipation ratio (referred to herein as "DR.") associated with each of a plurality of MSEs.
  • DR. dissipation ratio
  • a “dissipation ratio” (or “absorption efficiency” or “power efficiency”) may be defined as a ratio between electromagnetic energy absorbed by object 1 1 and electromagnetic energy supplied into electromagnetic energy application zone 9.
  • absorbable energy or “absorbed energy.”
  • Absorbable energy may be an indicator of the object's capacity to absorb energy or the ability of the apparatus to cause energy to dissipate in a given object (for example - an indication of the upper limit thereof).
  • absorbed energy may be calculated as a product of the incident energy (e.g., maximum incident energy) supplied to the at least one antenna and the dissipation ratio.
  • Reflected energy e.g., the energy not absorbed or coupled
  • a processor might calculate or estimate absorbable energy based on the portion of the incident energy that is reflected and the portion that is coupled. That estimate or calculation may serve as a value indicative of absorbed and/or absorbable energy.
  • the at least one processor may be configured to control a source of electromagnetic energy (RF source) such that energy is sequentially supplied to an object at a series of MSEs.
  • the at least one processor might then receive a signal indicative of energy reflected at each MSE.
  • the at least one processor may also receive a signal indicative of the energy transmitted to other antennas at each MSE.
  • an absorbable energy indicator may be calculated or estimated.
  • the processor might simply rely on an indicator of reflection and/or transmission as a value indicative of absorbable energy.
  • Absorbed energy may also include energy that may be dissipated by the structures of the energy application zone in which the object is located (e.g., cavity walls) or leakage of energy at an interface between an oven cavity and an oven door.
  • absorption in metallic or conducting material e.g., the cavity walls or elements within the cavity
  • Q factor quality factor
  • MSEs having a large Q factor may be identified as being associated with conducting material, and at times, a choice may be made not to transmit energy in such MSEs.
  • the amount of electromagnetic energy absorbed in the cavity walls may be substantially small, and thus, the amount of electromagnetic energy absorbed in the object may be substantially equal to the amount of absorbable energy.
  • a dissipation ratio may be calculated using formula (1):
  • Pj n represents the electromagnetic energy and/or power supplied into zone 9 by antennas 102
  • P r f represents the electromagnetic energy reflected/returned at those antennas that function as transmitters
  • P cp represents the electromagnetic energy coupled at those antennas that function as receivers.
  • DR may be a value between 0 and 1, and thus may be represented by a percentage number.
  • corresponding to antenna 1 may be determined based on the above mentioned reflection and transmission coefficients, according to formula (2):
  • the value indicative of the absorbable energy may further involve the maximum incident energy associated with a power amplifier (not illustrated) of subsystem 96 at the given MSE.
  • maximum incident energy may be defined as the maximal power that may be provided to the antenna at a given MSE throughout a given period of time.
  • one alternative value indicative of absorbable energy may be the product of the maximum incident energy and the dissipation ratio.
  • the at least one processor may also be configured to cause energy to be supplied to the at least one radiating element in at least a subset of a plurality of MSEs.
  • Energy transmitted to the zone at each of the subset of MSEs may be a function of the absorbable energy value at the corresponding MSE.
  • energy transmitted to the zone at MSE(i) may be a function of the absorbable energy value at MSE(i).
  • the energy supplied to at least one antenna 102 at each of the subset of MSEs may be determined as a function of the absorbable energy value at each MSE (e.g., as a function of a dissipation ratio, maximum incident energy, a combination of the dissipation ratio and the maximum incident energy, or some other indicator).
  • the subset of the plurality of MSEs and/or the energy transmitted to the zone at each of the subset of MSEs may be determined based on or in accordance with a result of absorbable energy information (e.g., absorbable energy feedback) obtained during an MSE sweep (e.g., at the plurality of MSEs).
  • the at least one processor may adjust energy supplied at each MSE such that the energy at a particular MSE may in some way be a function of an indicator of absorbable energy at that MSE.
  • the functional correlation may vary depending upon application and/or a desired target effect, e.g., a more uniform energy distribution profile may be desired across object 1 1.
  • the invention is not limited to any particular scheme, but rather may encompass any technique for controlling the energy supplied by taking into account an indication of absorbable energy.
  • the at least one processor may be configured to cause energy to be supplied to the at least one radiating element in at least a subset of the plurality of MSEs, wherein energy transmitted to the zone at each of the subset of MSEs is inversely related to the absorbable energy value at the corresponding MSE.
  • Such an inverse relationship may involve a general trend, e.g., when an indicator of absorbable energy in a particular MSE subset (i.e., one or more MSEs) tends to be relatively high, the actual incident energy at that MSE subset may be relatively low. When an indicator of absorbable energy in a particular MSE subset tends to be relatively low, the incident energy may be relatively high.
  • This substantially inverse relationship may be even more closely correlated.
  • the transmitted energy may be set such that its product with the absorbable energy value (e.g., the absorbable energy by object 1 1) is substantially constant across the MSEs applied.
  • spatial uniformity may refer to a condition where the absorbed energy across the object or a portion (e.g., a selected portion) of the object that is targeted for energy application is substantially constant (e.g., per volume unit or per mass unit).
  • the energy absorption is considered “substantially constant” if the variation of the dissipated energy at different locations of the object is lower than a threshold value. For instance, a deviation may be calculated based on the distribution of the dissipated energy in the object, and the absorbable energy is considered “substantially constant” if the deviation between the dissipation values of different parts of the object is less than 50%.
  • spatial uniformity may also refer to a condition where the temperature increase across the object or a portion of the object that is targeted for energy application is substantially constant.
  • the temperature increase may be measured by a sensing device, for example, a temperature sensor provided in zone 9.
  • spatial uniformity may be defined as a condition, where a given property of the object is uniform or substantially uniform after processing, e.g., after a heating process. Examples of such properties may include temperature, readiness degree (e.g., of food cooked in the oven), mean particle size (e.g., in a sintering process), etc.
  • controller 101 may be configured to hold substantially constant the amount of time at which energy is supplied to radiating elements 102 at each MSE, while varying the amount of power supplied at each MSE as a function of the absorbable energy value.
  • controller 101 may be configured to cause the energy to be supplied to the antenna at a particular MSE or MSEs at a power level substantially equal to a maximum power level of the device and/or the amplifier at the respective MSE(s).
  • controller 101 may be configured to vary the period of time during which energy is applied to each MSE. This period of time may also be referred to as transmission time or transmission duration.
  • the transmission duration may be varied as a function of the absorbable energy value.
  • both the duration and power at which each MSE is applied are varied as a function of the absorbable energy value. Varying the power and/or duration of energy supplied at each MSE may be used to cause substantially uniform energy absorption in the object or to have a controlled spatial pattern of energy absorption, for example, based on feedback indicative of the dissipation properties of the object at each transmitted MSE.
  • controller 101 may be configured to cause the amplifier to supply no energy at all at particular MSE(s). Similarly, if the absorbable energy value exceeds a predetermined threshold, controller 101 may be configured to cause the antenna to supply energy at a power level less than a maximum power level of the antenna.
  • absorbable energy can change based on a host of factors including object temperature
  • the at least one processor may be configured to determine a desired and/or target energy absorption level at each of a plurality of MSEs and adjust energy supplied from the antenna at each MSE in order to obtain the target energy absorption level at each MSE.
  • controller 101 may be configured to target a desired energy absorption level at each MSE in order to achieve or approximate substantially uniform energy absorption across a range of MSEs.
  • controller 101 may be configured to provide a target energy absorption level at each of a plurality of object portions, which collectively may be referred to as an energy absorption profile across the object.
  • An absorption profile may include uniform energy absorption in the object, non-uniform energy absorption in the object, differing energy absorption values in differing portions of the object, substantially uniform absorption in one or more portions of the object, or any other desirable pattern of energy absorption in an object or portion(s) of an obj ect.
  • the at least one processor may be configured to adjust energy supplied from the antenna at each MSE in order to obtain a desired target energy effect and/or energy effect in the object, for example, a different amount of energy may be provided to different parts and/or regions of the object.
  • a resolution of the different regions may be a fraction of the wavelength of the delivered EM energy, e.g., on the order of ⁇ /10, ⁇ /5, ⁇ /2, etc.
  • the wavelength is approximately 9 times shorter at the same frequency (900MHz), thus the resolution may be in the order of 0.33 cm, e.g., (0.33cm) 3 .
  • the wavelength corresponding to frequency of 900MHz is about 7 times shorter than in air and the resolution may be in the order of 0.4 cm, e.g., (0.4cm) 3 .
  • the resolution may be in the order of: 0.1 cm, 0.05 cm, 0.01 cm, 5 mm, 1 mm, 0.5 mm, 0.1 mm, 0.05 mm or less.
  • Apparatus 400 may include an RF energy source 2050.
  • RF energy source 2050 may include an RF power supply 2012, a modulator 2014, and/or an amplifier 2016.
  • apparatus 400 may include a processor 2030 which may regulate modulations performed by modulator 2014.
  • modulator 2014 may include at least one of a phase modulator, a frequency modulator, and an amplitude modulator configured to modify the phase, frequency, and amplitude of an AC waveform generated by power supply 2012.
  • Processor 2030 may alternatively or additionally regulate at least one of location, orientation, and configuration of each radiating element 2018, for example, using an electro-mechanical device.
  • an electromechanical device may include a motor or other movable structure for rotating, pivoting, shifting, sliding or otherwise changing the orientation and/or location of one or more of radiating elements 2018.
  • processor 2030 may be configured to regulate one or more field adjusting elements located in the energy application zone 10, in order to change the field pattern in the zone.
  • apparatus 400 may involve the use of at least one source 2050 configured to deliver electromagnetic energy to the energy application zone 10.
  • the source 2050 may include one or more of a power supply 2012 configured to generate electromagnetic waves that carry electromagnetic energy.
  • power supply 2012 may be a magnetron configured to generate high power microwave waves at a predetermined wavelength or frequency.
  • power supply 2012 may include a semiconductor oscillator, such as a voltage controlled oscillator, configured to generate AC waveforms (e.g., AC voltage or current) with a constant or varying frequency.
  • AC waveforms may include sinusoidal waves, square waves, pulsed waves, triangular waves, or another type of waveforms with alternating polarities.
  • source 2050 of RF energy may include any other power supply, such as electromagnetic field generator, electromagnetic flux generator, or any mechanism for generating vibrating electrons.
  • source 2050 in apparatus 400 may include a phase modulator (not illustrated) that may be controlled to perform a predetermined sequence of time delays on an AC waveform, such that the phase of the AC waveform is increased by a number of degrees (e.g., 10 degrees) for each of a series of time periods.
  • processor 2030 may dynamically and/or adaptively regulate modulation based on feedback from the energy application zone. For example, processor 2030 may be configured to receive an analog or digital feedback signal from detector 2040, indicating an amount of electromagnetic energy received from cavity 10, and processor 2030 may dynamically determine a time delay at the phase modulator for the next time period based on the received feedback signal.
  • source 2050 in apparatus 400 may include a frequency modulator (not illustrated).
  • the frequency modulator may include a semiconductor oscillator configured to generate an AC waveform oscillating at a predetermined frequency.
  • the predetermined frequency may be in association with an input voltage, current, and/or other signal (e.g., analog or digital signals).
  • a voltage controlled oscillator may be configured to generate waveforms at frequencies proportional to the input voltage.
  • Processor 2030 may be configured to regulate an oscillator (not illustrated) to sequentially generate AC waveforms oscillating at various frequencies within one or more predetermined frequency bands.
  • a predetermined frequency band may include a working frequency band, and the processor may be configured to cause the
  • a working frequency band may be a collection of frequencies selected because, in the aggregate, they achieve a desired goal, and there is diminished need to use other frequencies in the band if that sub-portion achieves the goal.
  • the processor may sequentially apply power at each frequency in the working frequency band (or subset or sub-portion thereof). This sequential process may be referred to as "frequency sweeping.”
  • each frequency may be associated with a feeding scheme (e.g., a particular selection of MSEs).
  • processor 2030 may be configured to select one or more frequencies from a frequency band, and regulate an oscillator to sequentially generate AC waveforms at these selected frequencies.
  • processor 2030 may be further configured to regulate amplifier 2016 to adjust amounts of energy delivered via radiating elements 2018, based on the feedback signal.
  • detector 2040 may detect an amount of energy reflected from the energy application zone and/or energy transmitted at a particular frequency, and processor 2030 may be configured to cause the amount of energy delivered at that frequency to be low when the reflected energy and/or transmitted energy is low.
  • processor 2030 may be configured to cause one or more antennas to deliver energy at a particular frequency over a short duration when the reflected energy is low at that frequency.
  • the apparatus may include more than one source of EM energy.
  • more than one oscillator may be used for generating AC waveforms of differing frequencies.
  • the separately generated AC waveforms may be amplified by one or more amplifiers.
  • radiating elements 2018 may be caused to simultaneously transmit electromagnetic waves at, for example, two differing frequencies to cavity 10.
  • Processor 2030 may be configured to regulate the phase modulator in order to alter a phase difference between two electromagnetic waves supplied to the energy application zone.
  • the source of electromagnetic energy may be configured to supply electromagnetic energy in a plurality of phases
  • the processor may be configured to cause the transmission of energy at a subset of the plurality of phases.
  • the phase modulator may include a phase shifter.
  • the phase shifter may be configured to cause a time delay in the AC waveform in a controllable manner within cavity 10, delaying the phase of an AC waveform anywhere from between 0-360 degrees.
  • a splitter (not illustrated) may be provided in apparatus 400 to split an AC signal, for example generated by an oscillator, into two AC signals (e.g., split signals).
  • Processor 2030 may be configured to regulate the phase shifter to sequentially cause various time delays such that the phase difference between two split signals may vary over time. This sequential process may be referred to as "phase sweeping.” Similar to the frequency sweeping described above, phase sweeping may involve a working subset of phases selected to achieve a desired energy application goal.
  • the processor may be configured to regulate an amplitude modulator in order to alter an amplitude of at least one electromagnetic wave supplied to the energy application zone.
  • the source of electromagnetic energy may be configured to supply electromagnetic energy in a plurality of amplitudes, and the processor may be configured to cause the transmission of energy at a subset of the plurality of amplitudes.
  • the apparatus may be configured to supply electromagnetic energy through a plurality of radiating elements, and the processor may be configured to supply energy with differing amplitudes simultaneously to at least two radiating elements.
  • Fig. 4 and Figs. 2A and 2B illustrate circuits including two radiating elements (e.g., antennas 16, 18; 210, 220; or 2018), it should be noted that any number of radiating elements may be employed, and the circuit may select combinations of MSEs through selective use of radiating elements.
  • amplitude modulation may be performed with radiating elements A and B
  • phase modulation may be performed with radiating elements B and C
  • frequency modulation may be performed with radiating elements A and C.
  • amplitude may be held constant and field changes may be caused by switching between radiating elements and/or subsets of radiating elements.
  • radiating elements may include a device that causes their location or orientation to change, thereby causing field pattern changes.
  • the combinations are virtually limitless, and the invention is not limited to any particular combination, but rather reflects the notion that field patterns may be altered by altering one or more MSEs.
  • Fig. 5 is a flow chart of an exemplary method for applying electromagnetic energy to an object in accordance with some embodiments of the present invention.
  • Electromagnetic energy may be applied to an object, for example, through at least one processor (e.g., processor 2030) implementing a series of steps of method 500 of FIG. 5.
  • processor 2030 e.g., processor 2030
  • method 500 may involve controlling a source of electromagnetic energy (step 510).
  • a "source" of electromagnetic energy may include any components that are suitable for generating electromagnetic energy.
  • the at least one processor may be configured to control electromagnetic energy application subsystem 96 or RF energy source 2050.
  • the source may be controlled to supply electromagnetic energy at a plurality of MSEs (e.g., at a plurality of frequencies and/or phases and/or amplitude etc.) to at least one radiating element, as indicated in step 520.
  • MSEs e.g., at a plurality of frequencies and/or phases and/or amplitude etc.
  • Various examples of supplying MSEs, including sweeping as discussed earlier, may be implemented in step 520.
  • other schemes for controlling the source may be implemented so long as that scheme results in the supply of energy at a plurality of MSEs.
  • the at least one processor may regulate subsystem 96 to supply energy at multiple MSEs to at least one transmitting radiating element (e.g., antenna 102).
  • one or more processing instructions and/or other information may be obtained from a machine readable element (e.g., a barcode or a RFID tag).
  • the machine readable element may be read by a machine reader (e.g., a barcode reader, an RFID reader) and may be provided to the processor and/or the controller by an interface.
  • a user may provide one or more processing instructions and/or may provide other information relating to the object (e.g., an object type and/or weight) through an interface, e.g., a GUI interface, a touch screen etc.
  • the method may further involve determining a value indicative of energy absorbable by the object at each of the plurality of MSEs, in step 530.
  • An absorbable energy value may include any indicator, whether calculated, measured, derived, estimated or predetermined, of an object's capacity to absorb energy.
  • computing subsystem 92 or processor 2030 may be configured to determine an absorbable energy value, such as a dissipation ratio associated with each MSE.
  • the method may also involve adjusting an amount of electromagnetic energy supplied or delivered at each of the plurality of MSEs based on the absorbable energy value at each MSE (step 540).
  • at least one processor may determine an amount of energy to be delivered at each MSE, as a function of the absorbable energy value associated with that MSE.
  • a choice may be made not to use all possible MSEs.
  • a choice may be made not to use all possible frequencies in a working band, such that the emitted frequencies are limited to a sub band of frequencies, for example, where the Q factor in that sub band is smaller or higher than a threshold.
  • a sub band may be, for example, 50 MHz wide, 100 MHz wide, 150 MHz wide, or even 200 MHz wide or more.
  • the at least one processor may determine a weight, e.g., power level, used for supplying the determined amount of energy at each MSE, as a function of the absorbable energy value.
  • a weight e.g., power level
  • amplification ratio of amplifier 2016 may be changed inversely with the energy absorption characteristic of object 1 1 at each MSE.
  • energy may be supplied for a constant amount of time at each MSE.
  • the at least one processor may determine varying durations at which the energy is supplied at each MSE. For example, the duration and power may vary from one MSE to another, such that their product correlates (e.g. inversely) with the absorption characteristics of the object.
  • the controller may use the maximum available power at each MSE, which may vary between MSEs. This variation may be taken into account when determining the respective durations at which the energy is supplied at maximum power at each MSE.
  • the at least one processor and/or controller e.g., controller 101
  • the method may also involve transmitting and/or applying and/or supplying electromagnetic energy at a plurality of MSEs (step 550). Respective weights may be assigned to each of the MSEs to be transmitted (step 540), for example, based on the absorbable energy value (as discussed above). Electromagnetic energy may be supplied to cavity 10 via antennas, e.g., antenna 102, 16, 18, or 2018.
  • Energy application may be interrupted periodically (e.g., several times a second) for a short time (e.g., only a few milliseconds or tens of milliseconds).
  • energy application termination criteria may vary depending on application. For example, for a heating application, termination criteria may be based on time, temperature, sound velocity, total energy absorbed, or any other indicator that the process at issue is compete. For example, heating may be terminated when the temperature of object 1 1 rises to a predetermined temperature threshold. In another example, in thawing application, termination criteria may be any indication that the entire object is thawed.
  • step 560 If in step 560, it is determined that energy transfer should be terminated (step 560: yes), energy transfer may end in step 570. If the criterion or criteria for termination is not met (step 560: no), it may be determined if variables should be changed and reset in step 580. If not (step 580: no), the process may return to step 550 to continue transmission of electromagnetic energy. Otherwise (step 580: yes), the process may return to step 520 to determine new variables. For example, after a time period has lapsed, the object properties may have changed; which may or may not be related to the electromagnetic energy transmission.
  • Such changes may include temperature change, translation of the object (e.g., if placed on a moving conveyor belt or on a rotating plate), change in shape (e.g., mixing, melting or deformation for any reason), volume (e.g., shrinkage or puffing), or water content (e.g., drying), change of flow rate, change in phase of matter, chemical modification, etc. Therefore, it may be desirable to change the variables of transmission.
  • the new variables that may be determined may include: a new set of MSEs; an amount of electromagnetic energy supplied or delivered at each of the plurality of MSEs; weight, e.g., power level, of the MSE(s); and duration at which the energy is supplied at each MSE. Consistent with some of the presently disclosed embodiments, less MSEs may be swept in step 520 performed during the energy application phase than those swept in step 520 performed before the energy application phase, such that the energy application process is interrupted for a minimum amount of time.
  • Apparatus 600 may include additional components, including, for example, components discussed in reference to apparatus 100 and/or 400.
  • Apparatus 600 may include energy application zone 602.
  • Energy application zone 602 may include any zone, volume, cavity, etc. associated with, for example, a cooking oven, baking oven, furnace, chemical reactor, filter, catalytic converter, combustion chamber, burner in a gas turbine, plasma lamp, etc.
  • Object 610 may be placed at least partially inside zone 602. RF energy may be emitted (applied) to zone 602 from one or more radiating elements 604.
  • Radiating element(s) 604 may include any antenna or other radiating element configured to apply RF energy to zone 602.
  • Each of radiating elements 604 may be connected to a separate RF source (e.g., source 2050) or two or more of elements 604 may be connected to a single RF source and may be controlled by a processor (e.g., processor 2030).
  • RF energy application to zone 602 may be conducted in accordance with any of the methods disclosed above, for example method 500 presented in the flowchart in Fig. 5.
  • Apparatus 600 may further include at least one ultrasound (US) sensor configured to measure a signal related to the sound velocity in object 610.
  • the sensor may include at least one Ultrasonic transducer 608 and/or at least one US detector 609.
  • the US sensor may be configured as a transceiver.
  • more than one sensor may be installed in zone 602.
  • at least one transducer 608 may be located at a first point in the energy application zone (e.g., point 1) and at least one detector 609' may be located at a second point in the energy application zone (e.g., point 2).
  • at least two transceivers each comprising a transducer (e.g.
  • a detector e.g. 609 or 609'
  • the sensor(s) may be installed outside zone 602.
  • one or more of sensors for example, one or more of transducers 608, 608' and detectors 609, 609'
  • two or more sensors may be installed, such that each sensor may measure a sound velocity in a different direction across object 610.
  • two sensors may be installed facing each other, such that each may detect sound coming from the other and passing through the object.
  • the two sensors may be installed on two opposing outside surfaces of energy application zone 602 in opposite sides (e.g., ends, faces, walls, etc) with respect to each other.
  • the Sensors e.g., transducer 608
  • the Sensors may be connected to a processor (e.g., processor 2030).
  • the processor may be the same processor that controls the RF energy application via elements 604. Alternatively, different processors may be configured to control the RF energy application and determine the temperature of the object based on a signal received from transducer 608 and detector 609. In some embodiments, the processor may receive from the sensor(s) the traveling time of the sound wave from a transducer 608 to a detector 609' (e.g., from point 1 to point 2). Additionally, the processor may receive the traveling time of the sound wave from point 2 to point 1. In some embodiments, the processor may further receive additional information in order to determine the sound velocity and the temperature of the object.
  • the processor may receive, e.g., via an interface, the identity of the object and the physical distance between the sensors (e.g., between transducer 608 at point 1 and detector 609' at point 2).
  • the interface may include a user interface (e.g., a graphical user interface), a reader of machine readable elements, and/or a communication link configured to communication with a remote location, e.g., to an Internet server.
  • the determination of the temperature of the object may involve additional information (e.g. the distance between the transducer and the receiver) in addition to the signal related to the sound velocity in the object.
  • the senor may be configured to detect the sound velocity of a traveling wave between the transducer and the detector or may be configured to measure the time interval between the generation of the sound wave in the transducer and the detection of the sound wave in the detector. Such time interval may be referred to as traveling time. If only the time interval is detected by the sensor, additional information regarding the physical distance between the transducer and the detector may be used in order to determine the sound velocity.
  • the physical distance may be stored in a memory associated with the processor, and the processor may be configured to calculate the sound velocity based on the signal and the information. If the processor is configured to receive the sound velocity from the sensor, the physical distance between the transducer and the detector may be stored in a local processor embedded in or associated with the sensor. When the physical distance between sensors 608 and 609' is stored in at least one of the sensors, the processor may receive from the sensor the sound velocity in object 610 and not just the traveling time of the sound wave between the sensors.
  • the sound velocity in the object is known
  • additional information relating to the identity of the object may be used in order to determine the temperature of the object, because the sound velocity at a given temperature may vary among different objects.
  • the received or determined sound velocity may be compared with known data stored in a lookup table, for example, in a memory associated with the processor.
  • the data stored may include sound velocities in various objects at various temperatures, such that if the sound velocity and the kind of object are known, the temperature may be found from the table.
  • more than one pair of sensors may be installed in or outside zone 602. Each pair may measure a signal related to the sound velocity across different trajectories in the object, thus allowing determination of the temperature at locations along those trajectories. Each sensor pair may enable measurement of sound velocity at different portions of the object. If the object is larger than the cross section of the wave beam, it may be beneficial to use more than one pair of sensors.
  • RF energy application to zone 602 may be controlled based on the measured/determined sound velocity or the determined temperature. For example, RF energy may be applied to object 610 to heat object 610 to a certain temperature. Thus, when the object reaches a certain temperature, the RF energy application may be terminated. In yet another example, the object may need to be heated at a certain rate. Thus, if the sound velocity or the temperature does not increase at the desired or expected rate, the amount of energy applied to the zone 602 may be increased or decreased, as needed to achieve the desired or expected rate of temperature change.
  • the RF energy may be applied at various MSEs, and controlling the RF energy application may include selecting at least one MSE and/or selecting the amount of energy applied at that MSE, for example by varying the duration, along which power is applied at that MSE.
  • the processor may select and apply energy at certain MSEs in order to selectively apply energy to the different portions of the object.
  • the processor may control the RF energy to be applied at an MSE or energy application scheme that may excite a field pattern in zone 602 to apply more energy to portions of lower temperature, less energy to portions of high temperature, etc.
  • the processor may be configured to determine the temperature of object 610 when a fluid flows in energy application zone 602 and/or in object 610.
  • the flowing fluid may interact with the sound waves generated by US sensors as discussed above.
  • the processor e.g. processor 2030
  • the processor may be configured to receive an amount of time for the sound wave to travel from transducer 608 located at point 1 to detector 609' located at point 2 and an amount of time for the sound wave to travel from transducer 608' located at point 2 to detector 609 located at point 1 to determine the temperature of object 610 and the velocity of the fluid flowing in or across object 610.
  • Fig. 7 is a diagrammatic representation of an exemplary pollution emission reduction device 700 in accordance with some embodiments of the invention.
  • Device 700 may also include components of one or more of apparatuses 100 and 400.
  • Device 700 may include, for example, a DPF, an SCR tank, or a catalytic converter.
  • Device 700 may include filter body 702.
  • Filter body 702 may be constructed from a conductive material including, for example, stainless steel, cast iron, copper alloys and/or other metals and alloys suitable for use in elevated temperature (e.g., above 600 °C).
  • Filter body 702 may include an inlet 703, where exhaust gasses may enter the device and an outlet 704, where the exhaust gasses may exit the DPF.
  • Exhaust gasses may be the product of combustion of diesel fuel in a diesel combustion engine. Diesel exhaust gasses may contain hazardous soot particles.
  • Device 700 may be configured to trap at least a portion of the soot particles and burn the trapped soot particles using RF energy.
  • the energy application zone may be defined by the interior walls of filter body 702.
  • Device 700 may comprise a filter 706.
  • Filter 706 may include a porous filter, a core, or a tank.
  • the porous filter may have a honeycomb shape or an arbitrary porous shape.
  • the filter may be made from ceramic material such as metallic oxides (e.g., alumina, low iron cordierite, aluminosilicates or silica) having low loss tangent (low EM losses) or carbides (e.g., SiC) having medium loss tangent or metals.
  • Carbides such as SiC are medium EM absorbers especially in the RF range and may initiate a chain combustion process.
  • a coating material may be used to coat filter 706.
  • Coating the filter with a coating material for example, Ti0 2 , BaTi0 4 , oxides and mixtures thereof, by a thickness of several microns may provide a thin layer of high dielectric material that may absorb EM energy and heat.
  • the coating may also be used to tune pore size.
  • Device 700 may further include at least one radiating element (not illustrated).
  • the radiating element may be embedded in filter 706 or may be immersed in the tank.
  • the radiating elements may be installed in proximity to the filter, the core, or the tank.
  • a plurality of radiating elements may be embedded in the filter or the core, or be immersed in the tank.
  • the filter may be made of or composed of a conductive material and may function as the radiating element.
  • pollution emission reduction device 700 may be assembled in vehicles powered by an internal combustion engine, for example, diesel or gasoline powered passenger cars, buses, trucks, motorcycles, etc. Device 700 may be included in any systems powered by combustion engines where a reduction in pollution emission by the system may be desired. Pollution emission reduction device 700 may also be included in systems where reduction of pollution emissions may be required, including, for example, air filtering systems. [00147] EM energy, for example in the RF range (may be referred to as RF energy), may be applied to at least a portion of device 700. In some embodiments, only a portion of filter 706 may be heated, while avoiding heating other portions of the filter.
  • RF energy for example in the RF range
  • EM energy may be applied in order to burn soot particles trapped in one area in filter 706.
  • RF energy may be applied sequentially to one or more areas (e.g., to all portions) of filter 706.
  • one or more radiating element(s) e.g., elements 102 or 2018
  • EM energy application to each area may be done by applying EM energy to a radiating element embedded in or located in proximity to that area, for example, a near field element attached to the outer face of filter 706 (near the inner face of filter body 702).
  • an array of radiating elements e.g.
  • array 102a) may be embedded in filter 706, and may be configured to apply energy to the entire volume of the part.
  • a length of radiating element(s) may be a function of the wavelength of the applied EM energy, e.g., ⁇ /2.
  • a phase difference may be set between at least two radiating elements.
  • Selecting MSEs (by a processor, e.g., processor 2030) that includes various phase differences (e.g., 0, 45[deg], 90[deg], 135[deg], etc.) between at least two radiating elements may cause shift in the intensity maxima of an RF field excited in the filter (e.g., the intensity maxima of a first phase differences configuration may differ from the intensity maxima of a second phase differences configuration).
  • the processor may control the shifting such that RF energy may be applied to different sections (e.g., parts, partitions, regions) in the filter. In some embodiments, controlling the RF energy application to more than two sections (areas) may be done using at least two radiating elements.
  • the invention is not limited to any configuration and location of radiating elements.
  • Radiating element(s) may be connected to a power source (not illustrated), for example, through a coaxial cable.
  • radiating elements may not be connected to a power source and the EM energy may be coupled to radiating element(s) from another radiating elements not provided in filter 706 but in close proximity to filter 706.
  • DPF 700 may further include at least two US sensors 708 configured to measure the sound velocity in the DPF.
  • Each of sensors 708 may include at least one US transducer and at least one US detector.
  • sensors 708 may include transceivers.
  • each of sensors 708 may include at least one piezoelectric crystal capable of generating US waves in response to an electrical signal and capable of receiving US waves and converting the resulting mechanical vibration to electrical signals.
  • Sensors 708 may be located outside filter body 702, in proximity to the surface of filter body 702.
  • a US adapting gel may be added between the surface of sensors 708 and the surface of body 702.
  • sensors 706 may be installed in device 700 such that an angle ⁇ is formed between the traveling direction of the US waves and the flow direction of the exhaust gasses (see arrow 712 in Fig. 7).
  • ⁇ may be substantially close to 90°.
  • ⁇ may be any angle between 0°-180°.
  • sensors 708 may be connected to a processor (e.g., processor 2030) configured to receive feedback relating to the sound velocity from the sensors and determine the temperature of at least a portion of filter 706 based on the received feedback.
  • the processor may receive the traveling time of the sound wave from point 1 to point 2.
  • the processor may receive the traveling time of the sound wave from point 2 to point 1.
  • the processor may be configured to determine the sound velocity within the object, e.g., within fluid flowing inside the object, based on the received traveling times, the known dimensions of device 700, and the location of sensors 708.
  • the processor may further be configured to associate the determined sound velocity with data related to the sound velocity in filter 706 at various temperatures, stored in a memory associated with the processor, in order to determine the temperature of filter 706.
  • sensors 708 may be connected to each other mechanically by an adjustable arm 710.
  • Adjustable arm 710 may be configured to move or slide sensors 708 along the outer surface of device 700.
  • the processor may be configured to control the sliding of sensors 708 in order to determine the sound velocity and the temperature at different portions of filter 706.
  • RF energy application to device 700 may be controlled based on the determined sound velocity and/or determined temperature (as discussed above).
  • Fig. 8 is a flowchart of method 800 for determining a temperature of an object (e.g., object 610 or filter 706) placed in an energy application zone, for example, during the application of RF energy.
  • object e.g., object 610 or filter 706
  • a first signal related to a sound velocity in the object may be received by a sensor (e.g., US sensor 708) at step 810.
  • the first signal may be the sound velocity in the object measured between the first and second locations in the object (or in the energy application zone).
  • the first signal may include the traveling time of the sound wave between the first and second locations.
  • a first US wave may be generated by a first US sensor (e.g., a transducer 608) located at a first point (e.g., point 1).
  • the first point may be located in proximity to the object, in the energy application zone, or outside of energy application zone.
  • a sound wave generated at the first point may travel to a second point (e.g., point 2) and may further be detected by a detector (e.g., detector 609') located at the second point.
  • the traveling time of the sound wave may be measured by the sensor. If the distance between the transducer and the detector is known, the sound velocity in the object may be determined, e.g., in accordance with equation (A) or (E) above.
  • a processor e.g., processor 2030
  • the processor may be configured to control at least two sensors to detect at least two signals related to the sound velocity in the object at two different directions, and determine that the environment is non- flowing, if the signals are substantially similar, or that the environment is flowing, if the signals are substantially different. If the object is placed in a non-flowing environment, step 820-NO, the temperature of at least a portion of the object may be determined (e.g., by a processor) based on a single measurement of a signal related to the sound velocity in the object, at step 840.
  • the determination may be done using data associating sound velocities or signals related to sound velocities with various temperatures, for a known object(s), using database 850, which may include, for example, temperature/velocity data.
  • the data may be gathered by measuring the sound velocities at various temperatures in a particular reference object.
  • the temperature measurements may be acquired using any suitable temperature measurement method, and the signal related to sound velocity measurements may be conducted according to any suitable method, including, for example, the methods disclosed herein.
  • step 820-YES If the object is placed in a flowing environment, step 820-YES, an additional signal related to the sound velocity in the object may be received in step 830.
  • the signal may be received in a similar manner to the signal received in step 810.
  • the two signals may be used to determine the sound velocity and optionally the velocity of the fluid flow through the object.
  • the determined sound velocity and/or the measured signals may be used to determine the temperature of the object, as discussed above.
  • method 800 may further include generating an acoustic signal for receiving the first and/or second signal relating to the sound velocity in the object.
  • RF energy application may be controlled (e.g., by a processor) based on the determined temperature and/or the detected signal(s).
  • step 840 may be omitted and RF energy application may be controlled based on the detected signal(s) relating to the sound velocity in the object.
  • RF energy application may be terminated when the temperature in at least a portion of the object reaches a predetermined threshold, or the detected signal reaches a predetermined threshold.
  • the RF energy to the first portion may be terminated.
  • RF energy may be applied to the first portion in the DPF filter at a first MSE or a first sub-set of MSEs.
  • the temperature in the first portion reaches the predetermined threshold, the application of the RF energy at the first MSE (or first sub-set of MSEs) may be terminated.
  • a second portion of the DPF filter may be heated, for example, by applying RF energy at a second MSE or at a second sub-set of MSEs.
  • the processor may control the RF energy to be applied to the second portion of the DPF filter by controlling RF energy application at a second MSE or a second sub-set of MSEs.
  • the processor may be further configured to control the RF energy application by shifting the US sensor to detect a signal related to the sound velocity at several different portions of the object.
  • the processor may cause the application of the RF energy to a first portion until the temperature in the first portion reaches the predetermined threshold (e.g., 650°C in soot filter), and then control the US sensor to shift in location to a second portion of the object.
  • the processor may then check, according to the readings of the US sensor, if the second portion is at a temperature below a lower limit, and if so, control RF application so as to heat the second location.
  • the processor may control the US senor to shift to a third location, which may be the same or different from the first location.
  • the processor may detect several signals from various portions and then cause the application of RF energy to those portions (either sequentially or in parallel), or may detect a signal at a first portion and control the RF energy application to the first portion following by detecting a signal at a second portion and control the application of the RF energy to the second portion.
  • the processor may be configured to control the RF energy application based on a detected signal related to the sound velocity in the object.
  • the processor may cause the application of the RF energy to the object until the temperature of the object reaches the predetermined threshold (e.g., 650°C in soot filter).
  • the sound velocity determination may be based on a single measurement, at one portion of the object or may be based on a plurality of measurements, e.g., at a plurality of portions of the object.
  • the temperature of the object which may be used by the controller for determining the energy application, may be determined at one selected location or region of the object or may be determined based on temperature measurements of a plurality of locations or regions associated with the object.
  • Fig. 9 is a flow chart of a method 900 of heating an object according to some embodiments of the invention.
  • Method 900 includes a step 902 of heating the object with RF energy.
  • Method 900 may further include a step 904 of receiving a signal indicative of sound velocity inside the object.
  • the object is not necessarily homogeneous.
  • the object may include a diesel particulate filter (DPF), comprising a solid structure defining cells, through which gas may flow.
  • DPF diesel particulate filter
  • the sound velocity inside the object may be, in this case, sound velocity of gas inside the cells.
  • the sound velocity may depend on the temperature of the medium through which the sound travels. Therefore, the signal indicative of sound velocity inside the object may be also indicative of the temperature inside the object.
  • the sound is not necessarily audible to human beings.
  • the sound may include any acoustic wave of infra-sonic
  • Method 900 may further include a step 906 of checking if the received signal is indicative of sound velocity below or above a first predetermined threshold. If the signal indicative of sound velocity is below the first predetermined threshold (906: YES), this may indicate that the temperature inside the object is below a lower temperature limit, and heat should be applied to the object. Thus, method 900 may also include a step 908 of causing application of RF energy to heat the object when the signal is less than the first predetermined threshold. If the signal is not below (i.e., equal to or above) the first predetermined threshold (906: NO), method 900 may include a step 910 of checking if the signal is greater than a second predetermined threshold.
  • method 900 may include a step 912 of reducing the RF heating applied to the object, to allow the temperature to drop below the upper limit. Reducing the RF heating may include, for example, reducing the power at which RF is applied, stopping RF application, changing the MSE or MSEs applied, e.g., from current MSEs to MSEs that are less efficiently absorbed by the object, etc.
  • Changing the MSEs may include, for example, selecting frequency values, phase differences between radiating elements, or a value of any other controllable parameter that may affect the field pattern excited in the energy application zone.
  • cooling may be applied to the object.
  • cooling the object may affect not only the temperature of the object, but also the entire heating process.
  • cooling a plasma lamp may affect the efficiency of plasma generation within the lamp, the amounts of plasma, and the dielectric properties of the lamp.
  • the dielectric properties of the lamp may affect the ability of using the RF energy to heat the lamp. Thus cooling may affect not only the temperature but also the entire process of heating by RF energy.
  • the sound velocity is between the two predetermined thresholds, which may indicate that the temperature is within a target range.
  • some heat may be still applied (step 914), for example, by maintaining the amount of RF energy applied to the object for at least some time duration, to maintain, decrease, or increase the temperature.
  • the time duration may include, for example, 1 second, 30 seconds, 5 minutes, or any other time durations that may be appropriate considering the amount of RF power applied, the tendency of the object to absorb the applied RF power, and the heat capacity of the object.
  • the time duration may be predetermined.
  • the time duration may be as long as it takes for the object to get to the upper temperature limit.
  • RF energy application in step 914 may be the same as, or similar to, the RF energy application in step 908. In some embodiments, they may be different. For example, in step 914, less power may be applied, or power may be applied intermittently, or the heating may be otherwise adjusted to maintain the temperature of the object between the two thresholds. Heating the object with RF energy may be implemented for example by method 500 in apparatus 100 or 400. In some embodiments, heating the object with RF energy may be based or responsive to one or more feedback signals - for example: values indicative of energy absorbable by the object, e.g., DR.
  • Signals indicative of the sound velocity inside the object may be received regularly, e.g., at a predetermined period.
  • the signals may be received at predetermined times after carrying out energy application in step 908 or 914 and after reducing the RF energy application in step 912.
  • the predetermined time may differ during the implementation of the method. For example, the predetermined time after reducing RF heating in step 912 may be shorter or longer than that after applying RF energy in step 914.
  • the period between sound velocity measurements may depend on the sound velocity measured. For example, if the signal indicative of sound velocity inside the object is between the two predetermined thresholds, signal receipt may be more frequent than if it is below the first threshold.
  • method 900 may further include generating an acoustic signal.
  • the signal indicative of sound velocity within the object may include, for example, one or more of the echo of the acoustic signal, the travelling time of the acoustic signal through the object, the absorption of the acoustic signal in the energy application zone, and/or a signal indicative of the effect of the acoustic signal on RF radiation within the zone.
  • the acoustic signal may be generated by piezoelectric transducers as discussed above.
  • the acoustic signal may be generated by RF radiation modulated with a modulating signal having an acoustic frequency.
  • Fig. 10 provides diagrammatic illustrations of some waveforms that illustrate the method.
  • Waveform 1002 represents a waveform of an electromagnetic wave of frequency f RF in the RF range.
  • f RF may be lGHz.
  • Waveform 1004 represents a modulating signal having a frequency f A cousTic in the acoustic range, for example, 50kHz.
  • Waveform 1006 diagrammatically represents RF wave 1002 modulated by modulating signal 1004.
  • RF radiation having waveform 1006 into, for example, a plasma lamp may cause the plasma in the lamp to distribute in a particular shape, which may depend upon the acoustic mode excited in the lamp at the frequency f A cousTic-
  • the frequency of an acoustic mode that can be excited in the lamp may depend on the plasma temperature.
  • the excitation of the acoustic mode may cause the electromagnetic response of the plasma (and thus also the network parameters of a cavity surrounding the lamp) to change dramatically, e.g., through the generation of a typical spatial distribution of the plasma in the lamp in response to the acoustic excitation.
  • a large change in network parameters e.g., S parameters
  • the acoustic frequency at which this event happens may be indicative of the plasma temperature.
  • the efficiency of energy conversion from electrical energy to light emission by the lamp may depend strongly on the plasma temperature, such that relatively small deviations in temperature (e.g., of 10°C to about 20°C) may cause significant deterioration of the efficiency, of about 50%.
  • the above-described embodiment may allow measuring of the plasma temperature and, based on the measuring results, controlling of the RF heater to regulate the temperature of the lamp and to maintain the temperature within the desired temperature range, at which the efficiency is within about 10%, 20%, or 25% of the maximum.
  • a lookup table may be provided, associating resonance frequencies with energy conversion efficiencies, and a processor may control the RF heater to heat the lamp such that the efficiency is within a predetermined range without calculating the efficiency or the temperature.
  • Fig. 11 is a flowchart of method 1100, which in some embodiments may be utilized to identify an acoustic resonance in an object (e.g., in a plasma lamp).
  • Method 1 100 may include a step 1 102 of modulating a plurality of RF signals each with a different modulating signal.
  • the (non-modulated) RF signals may all be the same, for example, may all share a same frequency.
  • the modulating signals may have differing frequencies, all in the acoustic range (e.g., between 20kHz and 2000kHz).
  • Method 1100 may further include step 1 104, of applying the modulated RF signals to the object.
  • Method 1 100 may further include step 1 106, of generating a control signal for controlling a heater.
  • the heater may be an RF heater.
  • the heater may be an induction heater, or heat by IR, or by any other electrically controllable method.
  • the control signal may control the heater, e.g., to generate specified MSEs for specified periods at specified power levels.
  • the control signal may be indicative of sound velocity inside the object, and may be based on electromagnetic feedback received in response to the application of the plurality of modulated
  • the method may further include receiving the electromagnetic feedback, and generating the control signal based on the received electromagnetic feedback.
  • Electromagnetic feedback may include magnitude and/or phases of network parameters (e.g., scattering parameters, also referred to as S parameters), any parameter derivable therefrom (e.g., dissipation ratio (DR), reflection coefficients (gamma)), or any other parameter that may be indicative of energy absorbable in the object and/or electrical characteristics of the object.
  • network parameters e.g., scattering parameters, also referred to as S parameters
  • any parameter derivable therefrom e.g., dissipation ratio (DR), reflection coefficients (gamma)
  • DR dissipation ratio
  • gamma reflection coefficients
  • Fig. 12 is a diagrammatic illustration of an apparatus 1200 for heating an object 1202 by RF energy.
  • Apparatus 1200 may include less or more components.
  • apparatus 1200 may include components discussed in reference to apparatus 100 and 400, not illustrated in Fig. 12.
  • Object 1202 is shown within a resonant cavity 1204, also referred to herein as an energy application zone.
  • the object may be heated by RF energy applied through radiating elements 1206.
  • Two radiating elements are shown, but any number of radiating elements, e.g., 1, 3, 4, 10, etc., may also be used, depending on details of the specific apparatus, for example, the size and shape of the energy application zone.
  • the radiating elements may connect to an RF operating system 1208, which may include, for example, one or more sources of electromagnetic energy 2050 (also referred as RF source), one or more detectors 2040, and at least one processor 2030. Interconnections among a source, a detector, a controller, and radiating elements according to some embodiments of the invention are shown in Fig. 4, discussed above.
  • RF operating system 1208 and radiating elements 1206 may together form an RF heater.
  • energy application zone 1204 may also be part of the RF heater.
  • Apparatus 1200 may also include one or more acoustic sensors 1210. Each of the acoustic sensors may include an acoustic transceiver.
  • the acoustic sensors 1210 may be connected to an acoustic operating system 1212, which may control application of AC waveforms to sensors 1210, and receive from them signals indicative, for example, of the time lapsing between generation of a signal by one transceiver and receipt of the signal by the other transceiver.
  • Both RF operating system 1208 and acoustic operating system 1212 may be controlled by a control unit 1214.
  • control unit 1214 may be included in processor 2030.
  • control unit 1214 may receive from acoustic operating system 1212 a signal indicative of sound velocity within object 1202.
  • the signal may include, for example, a time period between generation of a signal by one transceiver 1210 and receipt of the signal by the other transceiver 1210.
  • Control unit 1214 may use this signal to search in a lookup table for operating instructions for the RF operating system 1208.
  • the lookup table may be stored on a digital memory accessible to control unit 1214.
  • the operating instructions may include adjusting power level, MSE selection, and/or any other instruction that may affect the heating by the RF heater upon execution.
  • Control unit 1214 may then send a control signal indicative of the operating instructions found in the lookup table, and processor 2030 may command RF application by the RF heater in accordance with the control signal received from control unit 1214.
  • acoustic operating system 1212 may receive from control unit 1214 instruction to sweep acoustic frequencies at some range. Operating system 1212 may then carry out the instructions by controlling the frequency of AC power to sensors 1210.
  • RF operating system 1208 may receive instructions from control unit 1214 to measure, and send to the control unit measurement results of S parameters detected in energy application zone 1204.
  • Processor 2030 may, in response, instruct source 2050 to supply RF energy to energy application zone 1204.
  • the instructions may include applying RF energy at low power, sufficient for measurements of the S parameters, but not for further heating of object 1202.
  • Detector 2040 may detect feedback from the energy application zone and send it to control unit 1214.
  • Control unit 1214 may receive, concurrently, acoustic frequencies applied and S parameters measured, and identify an acoustic frequency at which the S parameters change abruptly. Control unit 1214 may search for this frequency in a lookup table, associating acoustic frequencies to RF heating instructions, and instruct RF operating system 1208 based on the instructions found in the table.
  • Fig. 13 is a diagrammatic illustration of processor 2030 (also shown in Fig. 4) according to some embodiments of the invention.
  • Processor 2030 may include an RF input 1302, an acoustic input 1304, and a control output 1310.
  • Processor 2030 may receive via RF input 1302 electromagnetic feedback from the energy application zone, e.g., from detector 2040 (Fig. 4). The electromagnetic feedback may be indicative of electrical characteristics of the object to be heated.
  • Processor 2030 may further receive, via acoustic input 1304, a signal indicative of sound velocity inside the object.
  • Acoustic input 1304 may be connected to a targeting module 1306.
  • the targeting module may have access to a digital storage 1308, storing the first and the second predetermined thresholds.
  • Targeting module 1306 may decide, based on input received through input 1304, if the signal indicative of sound velocity in the object is under the first predetermined threshold, above the second predetermined threshold, or between the two thresholds. Based on this decision, targeting module 1306 may set a target for the heating process.
  • the target may include, for example, heat, maintain present temperature, or let cool.
  • Targeting module 1306 may send a control signal to scheme setting module 1312, configured to set an energy delivery scheme according to the control signal received from targeting module 1306.
  • Scheme setting module 1312 also receives input through RF input 1302.
  • the input may include, for example, S parameters of the energy application zone comprising the object, or other feedback indicative of the response of the object in the energy application zone to RF energy applied at a variety of MSEs.
  • scheme setting module 1312 may set an energy delivery scheme that will achieve the target heating result, considering the current response of the object to RF energy.
  • Scheme setting module 1312 may then output a control signal via control output 1310 to source 2050 (shown in Fig. 4) to deliver (apply) RF energy to the energy application zone according to the scheme set by the scheme setting module.
  • Fig. 14 is a flow chart of method 1400 of heating an object according to some embodiments of the invention.
  • Method 1400 may include step 1402 of applying RF energy to the object.
  • the energy application in step 1402 may be at sufficient power level and/or for sufficient duration, to allow measuring feedback indicative of electrical parameters of the object (e.g., S parameters of the energy application zone with the object therein). Nevertheless, the energy applied in step 1402 may at low pressure and/or for short duration, so as not to heat the object.
  • Method 1400 may further include a step 1404 of detecting changes in
  • the changes may occur in response to interaction between the object and acoustic waves.
  • the acoustic waves may penetrate the object, wholly or partially. If the object may change its electrical
  • Objects that may change electrical properties in response to sound waves may include clouds of free charges, such as plasma (e.g., in plasma lamps); piezoelectric crystals; some powders of nano-particles, for example, carbon nano-tubes; and others.
  • Method 1400 may further include a step 1406 of controlling heating of the object with RF energy.
  • the heating may be in response to the detected changes in the electromagnetic feedback.
  • the changes may occur in response to changes of frequency of acoustic waves interacting with the object.
  • an acoustic resonance may be excited in the object at some particular acoustic frequencies, and change the charge distribution of a plasma cloud, e.g., within a plasma lamp.
  • the change in charge distribution may be expressed in a corresponding change in S parameters or other
  • the feedback may change.
  • the frequency at which the feedback changes may be indicative of the temperature of the plasma.
  • Heating may be controlled based on this temperature (or directly based on the acoustic frequencies at which changes in the feedback were detected) to heat the plasma further, to maintain the plasma temperature within a predetermined range, etc.
  • Heating control may be achieved, for example, by controlling power level at which the RF energy is applied to the object and/or by selecting one or more modulation space elements (MSEs) at which the RF energy is applied to the object. For example, selecting MSEs that are better absorbed by the object may cause faster heating.
  • MSEs modulation space elements
  • method 1400 may further include generating the acoustic waves. In some embodiments, this may be achieved by operating acoustic transducers, e.g., as described above. In some embodiments, generating the acoustic waves may include applying RF waves modulated with a signal having a frequency within the acoustic range. In some embodiments, step 1402 may include applying RF energy with such modulated signals.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Investigating Or Analyzing Materials By The Use Of Ultrasonic Waves (AREA)

Abstract

L'invention porte sur des appareils et sur des procédés de chauffage d'un objet. Le procédé comprend l'application d'une énergie radiofréquence à l'objet. Le procédé comprend également la détection de changements dans la rétroaction électromagnétique reçue en réponse à l'application d'énergie radiofréquence, les changements se produisant en réponse à une interaction entre l'objet et des ondes acoustiques. Le procédé comprend en outre la commande du chauffage de l'objet par une énergie radiofréquence en réponse aux changements détectés dans la rétroaction électromagnétique.
PCT/US2012/066274 2011-11-22 2012-11-21 Commande d'une application d'énergie radiofréquence sur la base de la température WO2013078325A1 (fr)

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EP2941092A1 (fr) * 2014-04-14 2015-11-04 Miele & Cie. KG Procédé et appareil ménager
EP2983453A1 (fr) * 2014-08-04 2016-02-10 Miele & Cie. KG Procede et appareil menager
US10708987B2 (en) 2015-04-10 2020-07-07 At&T Intellectual Property I, L.P. Cooking apparatus for targeted thermal management
CN105955095A (zh) * 2016-02-02 2016-09-21 广州莱肯信息科技有限公司 一种微波扫频源
US11246191B2 (en) 2016-09-22 2022-02-08 Whirlpool Corporation Method and system for radio frequency electromagnetic energy delivery
US11051371B2 (en) 2016-10-19 2021-06-29 Whirlpool Corporation Method and device for electromagnetic cooking using closed loop control
US10993294B2 (en) 2016-10-19 2021-04-27 Whirlpool Corporation Food load cooking time modulation
US11041629B2 (en) 2016-10-19 2021-06-22 Whirlpool Corporation System and method for food preparation utilizing a multi-layer model
US11202348B2 (en) 2016-12-22 2021-12-14 Whirlpool Corporation Method and device for electromagnetic cooking using non-centered loads management through spectromodal axis rotation
US11197355B2 (en) 2016-12-22 2021-12-07 Whirlpool Corporation Method and device for electromagnetic cooking using non-centered loads
US11184960B2 (en) 2016-12-29 2021-11-23 Whirlpool Corporation System and method for controlling power for a cooking device
US11452182B2 (en) 2016-12-29 2022-09-20 Whirlpool Corporation System and method for detecting changes in food load characteristics using coefficient of variation of efficiency
US11917743B2 (en) 2016-12-29 2024-02-27 Whirlpool Corporation Electromagnetic cooking device with automatic melt operation and method of controlling cooking in the electromagnetic cooking device
US11690147B2 (en) 2016-12-29 2023-06-27 Whirlpool Corporation Electromagnetic cooking device with automatic boiling detection and method of controlling cooking in the electromagnetic cooking device
US11638333B2 (en) 2016-12-29 2023-04-25 Whirlpool Corporation System and method for analyzing a frequency response of an electromagnetic cooking device
WO2018125144A1 (fr) * 2016-12-29 2018-07-05 Whirlpool Corporation Système et procédé de détection du niveau de cuisson d'une charge alimentaire
US11343883B2 (en) 2016-12-29 2022-05-24 Whirlpool Corporation Detecting changes in food load characteristics using Q-factor
US11412585B2 (en) 2016-12-29 2022-08-09 Whirlpool Corporation Electromagnetic cooking device with automatic anti-splatter operation
US11432379B2 (en) 2016-12-29 2022-08-30 Whirlpool Corporation Electromagnetic cooking device with automatic liquid heating and method of controlling cooking in the electromagnetic cooking device
US11102854B2 (en) 2016-12-29 2021-08-24 Whirlpool Corporation System and method for controlling a heating distribution in an electromagnetic cooking device
US11483906B2 (en) 2016-12-29 2022-10-25 Whirlpool Corporation System and method for detecting cooking level of food load
US11503679B2 (en) 2016-12-29 2022-11-15 Whirlpool Corporation Electromagnetic cooking device with automatic popcorn popping feature and method of controlling cooking in the electromagnetic device
CN109287927B (zh) * 2017-09-29 2022-12-02 恩智浦美国有限公司 用于灭菌、空气净化和解冻操作的多功能射频系统和方法
CN109287927A (zh) * 2017-09-29 2019-02-01 恩智浦美国有限公司 用于灭菌、空气净化和解冻操作的多功能射频系统和方法
DE102017219286A1 (de) * 2017-10-26 2019-05-02 BSH Hausgeräte GmbH Speisenbehandlungsgerät
US11953261B2 (en) 2017-10-26 2024-04-09 BSH Hausgeräte GmbH Food treatment device
US20200374992A1 (en) * 2019-05-21 2020-11-26 Ocean University Of China 433 MHz Solid State Microwave Heating Cavity and Industrial Defrosting System

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