RF Heating System with Liquid Intermediary for Uniform Pasteurization
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Solution Overview
Problem
Existing radio frequency (RF) energy heating systems face challenges in efficiently transmitting and launching RF energy due to the wavelength, which affects the heating process, particularly in achieving uniform and rapid temperature increases in packaged articles.
Innovation Solution
A process and system that involves passing articles through a liquid contact zone with an initial thermal regulation zone, an RF heating zone, and a subsequent thermal regulation zone, where RF energy is used to increase the temperature at the geometric center of the articles by at least 20°C, with a nonlinear travel path and energy-absorptive components to enhance energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If RF energy is used to heat articles, then rapid and effective heating is achieved, but efficient transmission and launching of RF energy becomes difficult due to wavelength
Solution Approach 1:
The patent introduces liquid as an intermediary medium between the RF energy source and the packaged articles. The liquid absorbs RF energy and transfers it to the articles through thermal conduction during contact, solving the problem of difficult RF energy transmission while maintaining rapid heating effectiveness
Solution Approach 2:
The patent replaces direct electromagnetic RF heating with a hybrid approach combining RF heating of liquid and thermal conduction to articles. This substitution allows the system to bypass RF transmission difficulties while achieving the desired heating effect through thermal energy transfer
2Productivity
If articles are heated rapidly with RF energy, then production rate is improved, but thermal degradation may increase
Solution Approach 1:
The patent creates different thermal environments for different parts of the heating process. Articles experience rapid RF heating when in contact with hot liquid, then cooler liquid contact afterward to reduce thermal degradation, providing localized quality control throughout the heating cycle
Solution Approach 2:
The patent implements periodic heating and cooling cycles through alternating contact with hot liquid (heating phase) and cooler liquid (cooling phase). This periodic action allows rapid temperature increases while subsequently reducing thermal degradation through controlled cooling intervals
3Device complexity
If a linear convey line is used, then device complexity is reduced, but heating uniformity and residence time control become insufficient
Solution Approach 1:
The patent employs a helical (curved) convey line instead of a linear path. This curvature increases the article travel path length within the liquid contact zone, improving heating uniformity and residence time control while maintaining relatively simple device configuration
Solution Approach 2:
The patent transitions from a one-dimensional linear convey path to a three-dimensional helical path. This dimensional change allows the articles to traverse a longer path through the heating zone, improving heat transfer uniformity without significantly increasing device complexity
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 effectively achieves uniform and rapid temperature increases, with the average temperature at the geometric center of the articles being raised by at least 20°C, while maintaining a small footprint and high production rate, minimizing thermal degradation and energy absorption rates.
Implementation Method 1
heating the articles on the convey line with RF energy in the RF heating zone
Implementation Method 2
passing a plurality of articles through a liquid contact zone of an RF heating system 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.