Combined RF and Thermal Heating for Fast Browning and Even Cooking
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Solution Overview
Problem
Conventional food heating systems either lack efficiency in heating uniformity, speed, or the ability to achieve desired Maillard reactions, such as browning and crisping, due to limitations in heating mechanisms like conventional ovens, convection ovens, and microwave ovens.
Innovation Solution
A heating appliance that combines a radio frequency (RF) heating system with a thermal heating system, utilizing a solid-state RF signal source and variable impedance matching networks to generate electromagnetic fields that penetrate deeper into food, combined with thermal heating systems like convection, radiant, or gas heating to achieve faster and more even cooking while enabling browning and crisping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional ovens use radiant heating elements, then Maillard reaction and browning are achieved, but cooking speed is slow
Solution Approach 1:
The patent combines microwave heating and radiant heating systems in a single oven cavity, allowing simultaneous internal heating via microwaves and surface heating via radiant elements. This merging enables both fast cooking and effective browning without requiring separate appliances or sequential processes.
Solution Approach 2:
The control system manages both heating systems to operate continuously and cooperatively throughout the cooking process. The radiant heating elements maintain surface temperature for browning while microwaves continue internal heating, ensuring both functions are performed simultaneously rather than alternately.
2Productivity
If microwave ovens use electromagnetic energy, then cooking speed is fast, but Maillard reaction and browning are not achieved
Solution Approach 1:
The patent integrates microwave generation and radiant heating capabilities within the same appliance, enabling the microwave to provide rapid internal heating while radiant elements simultaneously provide the high surface temperatures needed for Maillard reaction and browning.
Solution Approach 2:
The control system acts as an intermediary that coordinates between the microwave heating system and radiant heating system, managing power distribution and timing to ensure both systems work harmoniously to achieve both speed and browning quality.
3Stability of the object's composition
If convection ovens use fan assemblies, then cooking evenness is improved, but manufacturing and repair complexity increase
Solution Approach 1:
The patent replaces the mechanical convection fan system with stationary radiant heating elements positioned to naturally create convection currents. This substitution eliminates moving parts while maintaining temperature distribution through strategic placement of heating zones that promote natural air circulation.
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
The combined RF and thermal heating system rapidly heats food, provides more even internal heating, and achieves browning and crisping not possible with conventional systems alone, offering improved cooking performance in terms of speed and quality.
Implementation Method 1
an RF signal source configured to generate a radio frequency (RF) signal having a frequency in a range from about 10 megahertz (MHz) to about 100 MHz
Implementation Method 2
The electromagnetic energy (or microwave radiation) impinges on the food load to heat the outer layer of the food
Implementation Method 3
thermal heating systems like convection, radiant, or gas heating
Implementation Method 4
thermal heating systems like convection, radiant, or gas heating
Implementation Method 5
thermal heating systems like convection, radiant, or gas heating
Implementation Method 6
variable impedance matching networks to generate electromagnetic fields that penetrate deeper into food
Data Source
AI summary
An embodiment of a heating system includes a cavity configured to contain a load, a thermal heating system (e.g., a convection, radiant, and/or gas heating system) in fluid communication with the cavity and configured to heat air, and an RF heating system. The RF heating system includes an RF signal source configured to generate an RF signal, first and second electrodes positioned across the cavity and capacitively coupled, a transmission path electrically coupled between the RF signal source and one or more of the first and second electrodes, and a variable impedance matching network electrically coupled along the transmission path between the RF signal source and the one or more electrodes. At least one of the first and second electrodes receives the RF signal and converts the RF signal into electromagnetic energy that is radiated into the cavity.