RF Food Heating Control by Maximum Absorption Frequency
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Solution Overview
Problem
Existing microwave oven technologies do not achieve optimal heating of food ingredients due to fixed heating frequencies, which can lead to inefficient heating processes.
Innovation Solution
A method and apparatus that measure the spectrum of energy absorption of food ingredients across a range of radio frequencies to identify the frequency with maximum absorption, applying an electrical field at this frequency for efficient heating, and dynamically adjust the frequency based on temperature changes and food type to optimize heating efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed heating frequency is used in microwave ovens, then the device complexity is reduced and operation is simplified, but the heating efficiency and energy absorption optimization deteriorate
Solution Approach 1:
The patent implements dynamic frequency selection by measuring the absorption spectrum of food ingredients and identifying the frequency with maximum energy absorption. The system dynamically adjusts the heating frequency based on the measured spectrum rather than using a fixed frequency, thereby optimizing heating efficiency while maintaining ease of operation through automated measurement and selection processes.
2Productivity
If the heating frequency is dynamically adjusted based on absorption spectrum measurement, then the heating efficiency and energy absorption are optimized, but the device complexity and measurement requirements increase
Solution Approach 1:
The system performs self-characterization by automatically measuring its own absorption spectrum at candidate frequencies and identifying the frequency with maximum absorption. This self-service approach eliminates the need for external complex measurement equipment or manual calibration, reducing overall device complexity while enabling dynamic frequency optimization for improved heating efficiency.
3Device complexity
If a fixed frequency is used, then the device structure is simplified, but the adaptability to different food ingredients and heating conditions deteriorates
Solution Approach 1:
The patent changes the operating parameter (heating frequency) based on the measured absorption spectrum of different food ingredients. By measuring the spectrum and selecting the frequency with maximum absorption for each ingredient type, the system achieves high adaptability to different foods while maintaining a relatively simple device structure through automated parameter selection rather than multiple fixed-frequency systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves heating efficiency by reducing heating time and ensuring maximum energy absorption, leading to more effective and efficient cooking processes.
Implementation Method 1
Microwave oven heats food by irradiating in the cooking chamber of the oven, an electromagnetic radiation in the microwave spectrum and causes polar molecules (e.g. water) in the food to rotate and build up thermal energy in a process known as the dielectric heating.
Implementation Method 2
for each of said given range of radio frequencies, obtaining a penetration depth of an electrical field having a radio frequency corresponding to the given radio frequency into the food ingredients
Implementation Method 3
measuring the ratio between the energy of the radio frequency electrical field reflected or absorbed from the food ingredients, and the energy of the radio frequency electrical field applied to the food ingredients
Data Source
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AI summary
The invention relates to a method (100) and apparatus for controlling the heating of food ingredients. The method comprises the step of measuring (110) the spectrum of energy absorption of the food ingredients in a given range of radio frequencies. The method also comprises the step of identifying (120), in said given range of radio frequencies, the radio frequency for which the food ingredients have the maximum energy absorption. The method also comprises the step of applying (130) an electrical field to the food ingredients, said electrical field having a radio frequency corresponding to said radio frequency for which the food ingredients have the maximum energy absorption. The step of measuring (110) comprises, for a plurality of selected radio frequencies in said given range of radio frequencies, the steps of: applying an electrical field on the food ingredients having a radio frequency corresponding to a given selected radio frequency in said plurality of selected radio frequencies; and, measuring the ratio between the energy of the radio frequency electrical field reflected or absorbed from the food ingredients, and the energy of the radio frequency electrical field applied to the food ingredients. The plurality of selected radio frequencies are selected from said given range of radio frequencies by the steps of: for each of said given range of radio frequencies, obtaining a penetration depth of an electrical field having a radio frequency corresponding to the given radio frequency into the food ingredients, and including the given radio frequency into the plurality of selected radio frequencies if the penetration depth of the electrical field having a radio frequency corresponding to the given radio frequency is equal to or larger than the thickness of the food ingredients in the direction of the electrical field applied to the food ingredients. This invention allows reducing the heating time of food ingredients.