RF Heating Duct With Electric Field Guiding Element
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Solution Overview
Problem
Existing heat treatment systems for food products using radio frequency (RF) energy face inefficiencies in energy coupling, leading to heterogeneous heating with local overheating and underheating, and fail to sterilize products without compromising quality.
Innovation Solution
A heat treatment system comprising a duct with a pressurized liquid and an RF heating zone with a main electrode and counter electrodes, along with an electric field guiding element made of conductive material, ensures homogeneous energy coupling and efficient sterilization by generating an electric field parallel to the duct axis, preventing hot and cold spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If prior art RF heating systems are used, then energy can be coupled into the system, but the energy coupling is inefficient and heterogeneous causing local overheating and underheating
Solution Approach 1:
A liquid medium is introduced as an intermediary between the RF electrodes and the packaged product. The liquid couples the RF energy to the package contents, enabling efficient and homogeneous energy transfer. The liquid is circulated through channels in contact with the package, acting as a mediator that distributes energy uniformly without direct electrode-package contact.
Solution Approach 2:
The system changes the physical state and parameters of the liquid medium (temperature, pressure, flow rate) to optimize energy coupling. The liquid is heated by RF energy and its temperature parameters are controlled to ensure efficient heat transfer to the product while preventing overheating. Pressure parameters are adjusted to maintain liquid circulation and contact with the package.
2Reliability
If prior art RF heating systems are used, then heating can be performed, but sterilization cannot be achieved without losing substantial product quality
Solution Approach 1:
The liquid medium serves as a thermal buffer and intermediary heat transfer agent. It absorbs RF energy uniformly and transfers heat to the product through controlled circulation, preventing direct high-energy RF exposure that would degrade product quality. The liquid mediates between the RF field and the product, enabling sterilization temperatures to be achieved without localized overheating.
Solution Approach 2:
The system implements continuous circulation of the liquid medium through the package during the heating process. This continuous flow ensures uniform heat distribution throughout the product, maintaining consistent temperature for effective sterilization while preventing hot spots that would damage quality. The process can be maintained continuously for both batch and continuous processing modes.
3Productivity
If prior art systems are used, then heating can occur, but hot spots and cold spots are created in the products
Solution Approach 1:
The circulating liquid acts as a thermal equalizer, absorbing RF energy in regions of high energy density and transporting it to regions of low energy density through forced circulation. This mediator approach redistributes thermal energy uniformly across the product, eliminating hot and cold spots while maintaining rapid heating rates.
Solution Approach 2:
The system uses hydraulic circulation of the liquid medium through controlled channels and pumps to distribute heat uniformly. The fluid dynamics principles are applied to ensure adequate flow rates and pressure to maintain continuous liquid contact with the package surfaces, enabling rapid and uniform heat transfer throughout the product volume.
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 uniform heating and sterilization of packaged food products without energy loss, allowing for both continuous and batch processing, ensuring consistent treatment conditions and maintaining product quality.
Implementation Method 1
an RF heating zone comprising a main electrode and (at least) a counter electrode configured for functionally connecting to an RF generator to generate (during operation of the RF generator) a first electric field in the duct between the main electrode and the counter electrode
Implementation Method 2
a duct having a duct axis, wherein the duct is configured for holding a liquid (especially wherein the duct holds the liquid during operation of the system)
Data Source
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AI summary
The invention provides a heat treatment system (1000) comprising a heat treatment apparatus (1) and a product transport system (200), wherein the heat treatment apparatus (1) comprises (i) a duct (100) having a duct axis (110), wherein the duct (100) is configured for holding a liquid (2), and (ii) an RF heating zone (5) comprising a main electrode (410) and a first counter electrode (420) configured for functionally connecting to an RF generator (400) to generate during operation a first electric field (490) in the duct (100) between the main electrode (410) and the first counter electrode (420) parallel to the duct axis (110); the product transport system (200) comprises an electric field guiding element (440) comprising an electrically conductive material(401), wherein the electric field guiding element is configured to be electrically insulated from the electrodes (410, 420) during transport through the duct (100);and the product transport system (200) is configured to transport a product (60) and the electric field guiding element (440) through the duct (100).