Composite Susceptor for Microwave Surface Heating
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Solution Overview
Problem
Standard microwave susceptor materials face challenges in achieving high conductivity without cracking, which affects their ability to provide effective surface heating for non-frozen foods, as increased thickness leads to electrical field strength issues and material failure.
Innovation Solution
A composite susceptor design incorporating a standard susceptor layer and a shielding layer with a source of mobile charges, such as a salt water solution on tissue paper, to enhance conductivity and prevent cracking, allowing for complete encasement of food products and efficient surface heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the metal layer within a standard susceptor material is increased, then the electrical conductivity is improved, but the electrical field strength rises to a level where the susceptor material yields (develops cracks)
Solution Approach 1:
The invention uses a composite structure consisting of a thin metal susceptor layer combined with a dielectric layer containing mobile charges (such as salt water solution in tissue paper). This composite approach allows the system to achieve high effective conductivity through the mobile charges in the dielectric layer while the thin metal layer remains below the threshold that would cause cracking, thus resolving the contradiction between conductivity and structural integrity.
Solution Approach 2:
The dielectric layer containing mobile charges acts as an intermediary between the thin metal susceptor layer and the food product. This intermediary layer enhances the overall conductivity and heating efficiency without requiring the metal layer to be thick, thereby preventing cracking while maintaining reliable electrical conductivity for effective surface heating.
2Strength
If a thin metal susceptor layer is used, then the structural integrity is maintained, but the electrical conductivity is insufficient for effective surface heating of non-frozen foods
Solution Approach 1:
The invention compensates for the low conductivity of thin metal layers by introducing a dielectric layer with high concentration of mobile charges (such as salt water solution). This composite structure combines the structural advantages of thin metal layers with the electrical conductivity benefits of the mobile charge-containing dielectric layer, enabling effective surface heating without cracking.
Solution Approach 2:
The invention changes the electrical parameters of the susceptor system by introducing mobile charges into the dielectric layer. This parameter change dramatically increases the effective conductivity of the overall susceptor structure, allowing thin metal layers to achieve the same heating effectiveness as much thicker metal layers would provide alone.
3Area of stationary object
If the susceptor covers a large area, then the surface heating coverage is improved, but the electrical field strength increases causing the susceptor material to yield
Solution Approach 1:
The composite structure of thin metal layer plus dielectric layer with mobile charges allows large-area coverage without proportionally increasing electrical field stress on the metal layer. The mobile charges in the dielectric layer distribute and manage the electrical field more effectively across large areas, preventing the stress concentration that would cause cracking in traditional thick metal susceptors.
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 composite susceptor achieves a temperature profile similar to conventional oven preparation, providing improved browning and crispness by shifting the heating pattern from volumetric to surface heating, while maintaining the integrity of the susceptor material.
Implementation Method 1
a shielding layer having a substrate including a source of mobile charges
Implementation Method 2
The composite susceptor achieves a temperature profile similar to conventional oven preparation, providing improved browning and crispness by shifting the heating pattern from volumetric to surface heating
Implementation Method 3
heating the food product in the container in a microwave oven
Implementation Method 4
provide additional thermal heating on the surface of food products that are heated in a microwave oven
Data Source
AI summary
Microwaveable packages having highly conductive susceptors and methods for using same are provided. In a general embodiment, the microwaveable packages include a container defining an interior and having a microwave shielding material surrounding the interior. At least a portion of the microwave shielding material is a highly conductive susceptor. The highly conductive susceptor may include a standard microwave susceptor layer and a layer including a substrate having a source of mobile charges. Methods for increasing a surface heating of a food product are also provided and include, in a general embodiment, providing a food product in an interior of a container, which has a microwave shielding material surrounding the interior, and heating the food product in the container in a microwave oven for a predetermined amount of time.