Perforated Induction Pan Bottom for Flatness and Bond Strength

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing cooking vessels made of aluminum for induction cooktops face challenges in achieving a strong, deformation-free bond between the ferritic steel disk and the aluminum bottom due to thermal expansion differences, leading to irregular liquid distribution and structural issues.

Innovation Solution

A cooking vessel with a differentiated perforation pattern on the ferritic steel plate, featuring macro-perforated areas for cohesion and elasticity, and micro-perforated areas for mass retention and electromagnetic interaction, ensuring a balanced void-to-solid ratio and uniform hole distribution without the need for complex profiling or counterbores.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a ferritic steel disk is applied to the aluminum bottom, then the vessel becomes suitable for induction cooktops, but thermal expansion differences cause bottom deformation and lifting

Engineering Contradiction:
Improveinduction cooktop compatibilityVSAvoidbottom flatness
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The ferritic steel disk is provided with through holes arranged in a symmetrical pattern, creating a porous structure that reduces the overall mass and thermal expansion of the magnetic layer. This allows the bottom wall to maintain flatness during heating while still providing sufficient magnetic properties for induction cooktop compatibility.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention creates a composite structure combining aluminum bottom wall with a perforated ferritic steel layer. The composite design optimizes both materials' properties: aluminum provides thermal conductivity and lightweight characteristics, while the perforated ferritic steel provides magnetic properties with reduced thermal expansion impact.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If a ferritic steel disk is applied to ensure magnetic properties, then induction heating is enabled, but strong tensions bend the bottom centrally lifting it from the cooktop

Engineering Contradiction:
Improveinduction heating capabilityVSAvoidthermal tension
Core Design Contradiction:
Adaptability or versatilityVSStress or pressure

Solution Approach 1:

The perforated structure of the ferritic steel disk reduces material density and thermal mass, thereby decreasing thermal expansion forces and associated tensions during heating cycles while maintaining adequate magnetic properties for induction heating.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The through holes are arranged in a specific symmetrical pattern with differentiated distribution, creating local variations in material density that balance thermal expansion stresses across the bottom wall surface, preventing central lifting.

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If the ferritic steel disk is applied with through holes, then thermal expansion stress is reduced, but the bonding strength between steel and aluminum must be maintained

Engineering Contradiction:
Improvethermal expansion resistanceVSAvoidbonding strength
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The perforated structure reduces thermal mass and expansion stress while the surrounding solid material maintains adequate bonding area. The hole pattern is designed to optimize the balance between stress reduction and bonding surface area.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The ferritic steel disk is segmented into solid regions and void regions through the hole pattern. This segmentation reduces overall thermal expansion while distributing bonding stresses across multiple localized bonding zones around the holes.

Inventive Principle:
Principle #1Segmentation

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 solution provides a strong, deformation-resistant bond between the ferritic steel and aluminum, ensuring efficient heat transfer and uniform liquid distribution while maintaining structural integrity and ease of manufacturing.

Implementation Method 1

which for generating heat take advantage of the electromagnetic induction principle

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

due to the different thermal expansion between steel material and aluminum material

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

quickly warms up and transfers the heat to the vessel of aluminum which adheres thereto

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3986213B1Cooking vessel for cooking food having a bottom wall with through holes arranged in a symmetrical manner
Publication Date: 2024.05.08 ZWILLING BALLARINI ITAL SRL
  • EP3986213B1 patent drawingFigure 1~2
  • EP3986213B1 patent drawingFigure 3
  • EP3986213B1 patent drawingFigure 3A

AI summary

A cooking vessel for cooking food is described comprising a body comprising in its turn a bottom wall and at least one side wall. The side wall extends from the bottom wall to define an inner compartment of the cooking vessel in which the food is arranged for being cooked. At least the bottom wall is made of aluminum. The cooking vessel also comprises at least one plate-like component consisting of a disk made of a ferromagnetic material, integrally coupled with the bottom wall at the respective outer surface, so as to at least partially cover the outer surface of the bottom wall. The plate-like component is provided with a plurality of through holes and is divided into a plurality of first perforated areas having a first value (VtS1) of void-to-solid ratio and into a plurality of second perforated areas having a second value (VtS2) of void-to-solid ratio, mutually alternated in a symmetrical manner. Each first perforated area, featuring a greater void-to-solid ratio, is in a weighted ratio with respect to the second perforated area, featuring a smaller void-to-solid ratio.