Induction griddles
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Solution Overview
Problem
Existing electric griddles using resistive heating elements suffer from inefficient heat transfer, leading to longer warmup and recovery times, and uneven temperature distribution across the cooking surface.
Innovation Solution
A multi-zone induction-based griddle with a multi-layer cooking surface, utilizing ferritic stainless steels for heat generation and non-ferritic metals like aluminum and copper for enhanced heat transfer and uniform temperature distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If resistive heating elements are used in electric griddles, then the griddle can be operated indoors, but the thermal efficiency is low (20-30%) and warmup time is long
Solution Approach 1:
The patent replaces resistive heating elements with induction heating technology, substituting a mechanical/electrical resistance-based heating system with an electromagnetic field-based heating system. The induction coil generates a magnetic field that directly induces eddy currents in the cooking surface, eliminating the inefficiencies of radiative heat transfer from resistive elements and achieving 70-80% thermal efficiency.
Solution Approach 2:
The patent changes the fundamental heating mechanism parameter from resistive heating to induction heating. This parameter change transforms the heating process from indirect radiative heat transfer to direct electromagnetic induction, fundamentally improving thermal efficiency and reducing warmup time.
2Loss of energy
If induction coils are used to generate heat, then thermal efficiency increases (70-80%), but the cooking surface has uneven temperature distribution with hot and cold spots
Solution Approach 1:
The patent employs a composite cooking surface structure with multiple layers having different thermal properties. The cooking surface consists of a top layer (e.g., stainless steel or cast iron) bonded to a bottom layer (e.g., aluminum or copper) with high thermal conductivity. This composite structure allows the induction coil to heat the bottom layer efficiently while the high-conductivity material distributes heat uniformly across the top cooking surface, eliminating hot and cold spots.
Solution Approach 2:
The high thermal conductivity layer acts as an intermediary between the induction coil and the cooking surface. It receives concentrated electromagnetic heating from below and redistributes the heat laterally across the cooking surface, mediating between the localized energy input and the requirement for uniform temperature distribution.
3Loss of time
If induction heating is used with a single layer cooking surface, then warmup time is short, but the cooking surface area is limited and temperature distribution is uneven
Solution Approach 1:
The multi-layer construction allows the cooking surface to achieve both rapid warmup and large effective area. The bottom layer with high thermal conductivity rapidly distributes electromagnetic energy across the entire cooking surface area, enabling both fast warmup and uniform heating of a large cooking area simultaneously.
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 solution provides a larger cooking surface with shorter warmup times, more targeted heating, and a uniform temperature distribution across each zone, improving cooking efficiency and performance.
Implementation Method 1
An alternating current flowing in the induction coil generates a localized magnetic field. In the presence of a cooking vessel (e.g., a pot or a pan) made with ferric metals, the cycling magnetic field induces eddy currents in the metal that generate ohmic heat in the metal.
Implementation Method 2
the cycling magnetic field induces eddy currents in the metal that generate ohmic heat in the metal
Implementation Method 3
the cycling magnetic field induces eddy currents in the metal that generate ohmic heat in the metal
Implementation Method 4
The purpose of the middle layer(s) is to enhance the heat transfer towards the entire cooking surface and to store proper amount of heat inertia in the system.
Data Source
AI summary
The invention relates to a cooking system utilizing a single-zone or multi-zone induction-based griddle that provides uniform heat across a cooking surface. The system provides a larger cooking surface, a shorter warmup time, and a more targeted heating with a more uniform temperature distribution. A multi-layer cooking surface may converting a magnetic field into a thermal field by employing ferritic stainless steels, e.g., in an upper and lower layer. A middle layer(s) enhances heat transfer towards the entire cooking surface and stores a proper amount of heat inertia in the system. The middle layer, e.g., of aluminum, copper, or carbon-based materials may be separated into zones separated by cavities filled with insulation materials. The system may be utilized for indoor or outdoor grills.