High intensity radio frequency heating of packaged articles
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Solution Overview
Problem
Radio frequency (RF) energy heating of articles faces challenges in efficient transmission and uniform heating due to its wavelength, leading to inefficiencies in heating processes.
Innovation Solution
A process and system involving a liquid contact zone with initial and subsequent thermal regulation zones, and an RF heating zone, where articles are passed through a nonlinear path to ensure temperature uniformity and efficient energy absorption, using RF energy to increase the geometric center temperature by at least 20°C, with a focus on maximizing energy absorption and minimizing residence time in the RF heating zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If RF energy is used to heat articles, then heating speed is improved, but transmission efficiency deteriorates due to wavelength issues
Solution Approach 1:
The patent introduces liquid as an intermediary medium between the RF energy source and the articles. The liquid absorbs RF energy and transfers it to articles through conduction and convection, bypassing the transmission efficiency problems of direct RF heating while maintaining rapid heating speeds.
Solution Approach 2:
The patent replaces direct electromagnetic RF heating with a hybrid system combining liquid-based thermal transfer (mechanical/thermal process) with RF energy input. This substitution allows the system to achieve efficient energy transfer while maintaining the speed benefits of RF heating.
2Temperature
If RF energy is used to heat articles, then heating effectiveness is improved, but temperature uniformity deteriorates
Solution Approach 1:
The liquid intermediary distributes thermal energy uniformly to articles through fluid circulation and conduction, eliminating the temperature hotspots and non-uniform heating characteristic of direct RF heating while preserving the overall heating effectiveness.
Solution Approach 2:
The patent employs a helical conveyor path that curves articles through the liquid contact zone, ensuring all surfaces of articles are exposed to the heated liquid uniformly, thereby achieving consistent temperature distribution across different article surfaces.
3Productivity
If articles are heated rapidly with RF energy, then productivity is improved, but energy absorption efficiency deteriorates
Solution Approach 1:
The liquid contact zone maintains continuous thermal contact with articles throughout the heating process, ensuring constant energy transfer. This continuous action allows rapid heating (high productivity) while maximizing energy absorption efficiency through sustained thermal exchange.
Solution Approach 2:
The liquid intermediary provides a large surface area for energy transfer and maintains intimate contact with articles throughout the heating process, enabling efficient energy absorption rates that support both high productivity and energy efficiency.
4Area of stationary object
If a compact RF heating system is designed, then device footprint is reduced, but heating uniformity deteriorates
Solution Approach 1:
The helical conveyor path packs a long article travel distance into a compact vertical space, creating a compact device footprint while ensuring articles are exposed to heated liquid uniformly throughout their entire surface area, maintaining heating uniformity.
Solution Approach 2:
The patent transitions from a horizontal linear heating path to a vertical helical path, utilizing the vertical dimension to achieve a compact footprint while the helical curvature ensures uniform liquid contact and heating across all article surfaces.
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 system achieves rapid and uniform heating of articles, with significant temperature increase and efficient energy absorption, while maintaining a compact footprint and high production rate, effectively addressing inefficiencies in existing RF heating technologies.
Implementation Method 1
heating the articles on the convey line with RF energy in the RF heating zone to thereby increase the average temperature at the geometric center of the articles by at least 20° C.
Implementation Method 2
regulating the temperature of the articles on the convey line in the initial thermal regulation zone to promote temperature uniformity of the articles
Implementation Method 3
passing a plurality of articles through a liquid contact zone of an RF heating system on at least one convey line while maintaining the articles in contact with a liquid
Data Source
AI summary
Heating systems utilizing radio frequency (RF) energy and methods for using the same to rapidly and uniformly heat packaged articles moving through the system on one or more convey lines. These systems may be useful for a variety of processes, including the pasteurization or sterilization of packaged foodstuffs.