Ferrite Grill Pan Heating Layer for Fast, Self-Limited Microwave Cooking
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Solution Overview
Problem
Conventional grill pans with microwave heat generation layers face challenges in achieving high temperatures quickly while preventing material deterioration and ensuring safety, as the Curie temperature of ferrite materials used is limited, leading to longer cooking times and potential overheating issues.
Innovation Solution
A grill pan design incorporating a heat generation layer made of ferrite powders containing Fe2O3, MnO, and ZnO, with a weight ratio of 11 to 24, which absorbs microwave energy efficiently, allowing for rapid temperature increase and saturation within the material's heat-resistant limits, preventing overheating and material breakdown.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ferrite materials with limited Curie temperature are used in the heat generation layer, then the grill pan can be manufactured with existing materials, but the cooking time is extended and high temperature cooking performance is degraded
Solution Approach 1:
The patent changes the Curie temperature parameter of the ferrite material from conventional values (below 220°C) to a higher range (220°C to 350°C). This parameter change enables the heat generation layer to maintain microwave absorption capability at higher cooking temperatures, thereby reducing cooking time while maintaining temperature control stability through the self-regulating Curie point mechanism.
2Temperature
If the Curie temperature of ferrite material is increased to achieve faster heating, then cooking efficiency is improved, but the risk of exceeding material heat-resistant limits and causing deterioration increases
Solution Approach 1:
The patent utilizes the Curie temperature point of ferrite material as a natural feedback mechanism. When the heat generation layer reaches the Curie temperature (220°C to 350°C), the ferrite material automatically loses its microwave absorption capability, which stops further heating. This self-regulating feedback prevents the placing face temperature from exceeding safe limits and causing material deterioration, while still enabling faster heating compared to conventional materials.
3Speed
If ferrite material with higher Curie temperature is used, then temperature rise speed is improved, but uniform temperature distribution and saturation control become more difficult
Solution Approach 1:
The patent optimizes the ferrite particle size distribution parameter in the heat generation layer, using particles ranging from 1 μm to 100 μm. This size distribution ensures uniform microwave absorption throughout the layer, promoting even heat generation and temperature distribution across the placing face. The higher Curie temperature range (220°C to 350°C) works synergistically with the particle size distribution to achieve both fast temperature rise and uniform temperature saturation.
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
This configuration enables faster cooking times, improved browning of food, and enhanced durability and safety by maintaining the grill pan's temperature within safe limits, reducing the risk of material damage and ensuring reliable performance.
Implementation Method 1
a heat generation layer made of a microwave heat generator containing ferrite which absorbs microwave energy and generates heat
Implementation Method 2
When the temperature reaches the Curie temperature, absorption of the microwave of the ferrite material stops. By using the ferrite material having the Curie temperature lower than the highest temperature in cooking for the heat generation layer made of the microwave heat generator, the ferrite itself controls absorption and stop of the microwaves, so that the temperature of the metal plate is maintained uniformly.
Data Source
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AI summary
The present invention provides a cooking apparatus including a base member having a placing face on which food is placed, and a heat generation layer (3) made of a microwave heat generator containing ferrite which absorbs microwave energy and generates heat. The ferrite contains Fe2O3, MnO, and ZnO, and a ratio by weight of the Fe2O3 to the ZnO lies in a range of 11 to 24. With the configuration, the temperature of the placing face of a grill pan as the cooking apparatus can be increased to predetermined temperature in short time and can be saturated to allowable heat resistant temperature or less of the material of the grill pan. Therefore, improvement in the performance of the grill pan cooking and durability, safety, and reliability can be realized.