Cookware with Selectively Bonded Layers to Reduce Hot Spots
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cookware with multi-layer composite constructions experiences hot spots and sticking issues due to uneven thermal conductivity, which shortens the lifespan of non-stick coatings and complicates cleaning.
Innovation Solution
A cookware design featuring a multi-layer composite construction with selectively bonded layers, where a stainless steel layer with raised dimples or bubbles is bonded to an aluminum core and a stainless steel exterior, using pressure and elevated temperature to create a differential bond that enhances uniform heating and reduces hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If aluminum or copper layers are bonded to stainless steel to increase thermal conductivity, then heating speed is improved, but hot spots occur on the cooking surface causing food sticking and premature PTFE degradation
Solution Approach 1:
The patent applies local quality by creating a multi-layer construction where the aluminum core layer has varying thickness - thinner at the center and thicker at the edges. This non-uniform thickness distribution locally adjusts thermal conductivity to prevent hot spots at the center while maintaining efficient heat transfer at the edges, resolving the contradiction between overall thermal conductivity improvement and hot spot prevention.
Solution Approach 2:
The patent uses composite materials by bonding aluminum or copper layers to stainless steel layers to create a multi-layer structure. This composite construction combines the high thermal conductivity of aluminum/copper with the durability and non-reactivity of stainless steel, achieving improved heating speed while preventing direct contact between food and reactive metals that cause sticking.
2Ease of operation
If PTFE non-stick coating is applied to the cook surface to prevent sticking, then ease of cleaning is improved, but the coating degrades prematurely due to localized hot spots limiting its useful life
Solution Approach 1:
The varying thickness of the aluminum core layer creates local thermal management - the thinner center section prevents excessive heat concentration that would degrade PTFE, while the thicker edge sections provide structural support and heat distribution. This local quality adjustment protects the PTFE coating from premature degradation while maintaining its non-stick properties throughout its service life.
Solution Approach 2:
The multi-layer construction with controlled thermal conductivity acts as a protective cushion for the PTFE coating by preventing extreme temperature fluctuations and localized hot spots before they can cause damage. This beforehand cushioning extends the useful life of the PTFE coating by creating a more stable thermal environment.
3Strength
If uniform bonding is applied across all layers to ensure structural integrity, then strength is improved, but thermal energy distribution becomes uneven causing hot spots on the cook surface
Solution Approach 1:
The patent applies local quality by creating differential bonding - strong bonding at the edges where structural integrity is critical, and controlled thermal resistance at the center where heat distribution needs to be managed. This selective bonding approach maintains overall structural strength while preventing hot spot formation through localized thermal management.
Solution Approach 2:
The multi-layer construction segments the thermal path through the cookware bottom, with each layer serving a specific function - stainless steel for structural integrity and non-reactivity, aluminum/copper for thermal conductivity, and controlled bonding interfaces for thermal management. This segmentation allows independent optimization of structural strength and thermal distribution.
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 design minimizes sticking problems and hot spots, extending the life of non-stick coatings and simplifying cleaning by ensuring uniform heat distribution across the cooking surface.
Implementation Method 1
the first layer is solid state bonded to the underlying second layer by the application of pressure along with elevated temperature
Implementation Method 2
a greater amount of thermal energy from the heat of the cooking range or the like is transmitted by conduction through the flat surfaces compared with the thermal energy conducted through the raised bubbles
Data Source
Figure 1~2B
Figure 3
Figure 4
AI summary
Cookware comprising a selectively bonded composite of at least two layers of materials wherein the first of the at least two layers of materials has a plurality of spaced-apart bubbles formed on its surface, defining a cooking surface of the cookware, and a second layer of two layers of material is bonded thereto, wherein the bonding between the bubbles and the second material is of a lesser degree than the bonding between the first and second layers of materials in areas intermediate the bubbles, whereby a coefficient of heat conductivity is greater in the intermediate areas than in the bubbles.