Dynamic capacitive RF food heating tunnel
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Solution Overview
Problem
Conventional conveyor ovens are inefficient in thawing frozen foods, as they rely on thermal conduction, leading to uneven thawing and prolonged times, while capacitive RF systems cause surface thawing faster than core thawing due to environmental temperature differences.
Innovation Solution
A multi-functional RF capacitive food preparation device using a combination of RF capacitive heating and cold air sources to uniformly thaw food products from the exterior surface to the interior core, with a cooking controller managing energy distribution to prevent thermal runaway and preserve food quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional conveyor ovens use thermal conduction for thawing, then the process is simple and equipment is basic, but thawing time is very long and thawing is uneven
Solution Approach 1:
The patent replaces thermal conduction (mechanical heat transfer) with RF capacitive heating (electromagnetic field heating) to thaw the food core. The RF heating system uses electromagnetic energy to directly heat the interior core of the food product, achieving rapid and uniform thawing without the prolonged times associated with conventional thermal conduction methods.
Solution Approach 2:
The patent changes the heating parameters by introducing RF capacitive heating at specific frequencies to achieve volumetric heating throughout the food product. This parameter change enables simultaneous heating of both the core and surface, fundamentally altering the thawing process from sequential (core then surface) to simultaneous, thereby reducing total thawing time.
2Manufacturing precision
If capacitive RF system is used in ambient environment, then thawing of core is achieved, but surface thaws substantially faster than core causing uneven thawing
Solution Approach 1:
The patent applies preliminary anti-action by introducing a cooling mechanism that counteracts the excessive surface heating caused by RF capacitive heating. The cooling system is activated simultaneously with or before the RF heating to prevent the surface from thawing too rapidly, thereby maintaining temperature balance between surface and core throughout the thawing process.
Solution Approach 2:
The patent applies local quality by providing different thermal treatments to different regions of the food product. The RF capacitive heating specifically targets the interior core with electromagnetic energy, while the cooling mechanism selectively cools the exterior surface. This localized approach ensures uniform thawing by addressing the specific thermal needs of each region rather than applying uniform treatment.
3Productivity
If rapid thawing is achieved with RF capacitive heating, then productivity increases, but thermal runaway may occur at surface level
Solution Approach 1:
The patent implements feedback control by continuously monitoring the temperature distribution within the food product during RF capacitive heating. The system uses temperature sensors and control algorithms to detect temperature gradients between surface and core, automatically adjusting the RF power output and cooling rate to maintain optimal thawing conditions and prevent thermal runaway.
Solution Approach 2:
The patent applies dynamics by making the heating and cooling rates adjustable and responsive to real-time conditions. The RF capacitive heating system and cooling mechanism operate with dynamic control, allowing the process parameters to change continuously based on food product characteristics, size, and temperature distribution, thereby maintaining process stability throughout the rapid thawing operation.
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 device achieves rapid, uniform thawing and improved food quality by simultaneously applying RF capacitive heat to the core and cold air to the surface, reducing water loss and simplifying food preparation with operator-selectable recipes and cycles.
Implementation Method 1
thawing the interior core with an RF capacitive heating source
Implementation Method 2
cooling the exterior surface with a cold air source
Data Source
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AI summary
A food preparation device may include a tunnel cavity having a prep portion and a cooking portion, a conveyor belt extending through a length of the tunnel cavity, a cooking controller operably coupled to the prep portion and the cooking portion to selectively distribute power to at least a radio frequency (RF) capacitive heating source and a cold air source in the prep portion and at least a heat source in the cooking portion, and an interface panel. The prep portion and the cooking portion are positioned in a linear series in the tunnel cavity. The RF capacitive heating source comprises a ground plate and an anode plate.