RF Food Heating Cavity with Multi-Frequency Uniformity Control
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Solution Overview
Problem
Conventional microwave ovens face challenges in achieving uniform heating, particularly for irregularly shaped objects such as organs and foods, due to limitations in frequency range and cavity mode structure, leading to hotspots and inefficient energy distribution.
Innovation Solution
The use of multiple frequency feeds and adjustable field elements within the microwave cavity allows for dynamic control of electromagnetic energy distribution, enabling uniform or non-uniform heating patterns based on the object's geometry and absorption characteristics, with real-time temperature monitoring and feedback for optimal energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional microwave ovens are used for heating, then heating speed is improved, but temperature uniformity deteriorates
Solution Approach 1:
The microwave cavity is divided into multiple independent mode regions, each capable of generating different field patterns. Multiple magnetrons operate independently to excite different cavity modes, allowing the heating field to be segmented and recombined to achieve uniform temperature distribution while maintaining high heating speed.
Solution Approach 2:
Multiple cavity modes are merged and superimposed within the same cavity space. By simultaneously exciting different modes with multiple magnetrons, the patent combines their heating effects to produce a uniform temperature field that maintains both speed and uniformity.
2Stability of the object's composition
If multiple frequency feeds are used, then temperature uniformity is improved, but device complexity increases
Solution Approach 1:
A single microwave cavity serves multiple functions by supporting and exciting multiple different cavity modes simultaneously. The same physical cavity structure generates different field patterns through mode excitation, eliminating the need for separate heating chambers or complex multi-frequency feed systems while achieving uniform temperature distribution.
3Productivity
If heating power is increased, then productivity is improved, but harmful factors increase
Solution Approach 1:
The patent dynamically controls the operation of multiple magnetrons, adjusting their power levels and excitation patterns in real-time. This dynamic control allows the system to maintain high overall heating power for productivity while individually regulating each magnetron's contribution to prevent localized overheating and hotspot formation.
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 ensures that the temperature variation within the object is maintained within a narrow range, achieving uniform heating across irregularly shaped objects with improved efficiency and reduced hotspots, allowing for precise control of heating processes like defrosting and cooking.
Implementation Method 1
a method of heating an object in a cavity having at least one microwave port, comprising: feeding energy into at least one port; and varying the frequency of the energy during heating of the object
Implementation Method 2
feeding electromagnetic energy at a first frequency into the cavity via a first feed; and feeding electromagnetic energy at a second frequency into the cavity via a second feed
Data Source
AI summary
Devices and methods for RF heating of food, using techniques which allow uniformity and/or controlled non-uniformity.