Multi-Layer Susceptor Structure for Diffusion-Resistant Inductive Heating
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Solution Overview
Problem
Existing susceptor arrangements for inductively heating aerosol-forming substrates face issues with material diffusion and aging, which affect their performance and reliability.
Innovation Solution
A multi-layer susceptor arrangement is introduced, comprising a first layer for primary heating, a second layer as a temperature marker, and a third protective layer with a Ni-Fe-alloy having a Ni content of 65 wt% or less, where the third layer is thinner than 50% of the first layer, enhancing protection against material diffusion and aging while maintaining effective temperature monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a multi-layer susceptor arrangement with a second susceptor material layer is used for temperature monitoring, then temperature control precision is improved, but material diffusion into the aerosol-forming substrate and material aging occur
Solution Approach 1:
A third protective layer is introduced as an intermediary barrier between the second susceptor material layer and the aerosol-forming substrate. This protective layer prevents direct contact and chemical interaction, thereby stopping material diffusion and corrosion while allowing the second layer to maintain its temperature monitoring function through its Curie temperature transition.
Solution Approach 2:
The susceptor arrangement is segmented into three distinct functional layers: a first susceptor material layer for primary heating, a second susceptor material layer for temperature monitoring, and a third protective layer for preventing material diffusion and corrosion. This segmentation allows each layer to perform its specific function independently while working together as a integrated system.
2Reliability
If the third protective layer is made thicker to improve protection against material diffusion and aging, then reliability is improved, but material savings are reduced and inductive heating efficiency may be affected
Solution Approach 1:
The thickness of the third protective layer is optimized to a specific parameter range (equal to or smaller than 50% of the first layer thickness). This parameter optimization ensures sufficient protection against material diffusion and aging while minimizing material consumption and maintaining inductive heating efficiency by avoiding excessive thickness that would impede magnetic field penetration.
3Reliability
If the third protective layer is made thicker to enhance corrosion resistance, then reliability is improved, but heat transfer efficiency to the aerosol-forming substrate may be reduced
Solution Approach 1:
The thickness of the third protective layer is controlled within an optimized range (equal to or smaller than 50% of the first layer thickness) to balance corrosion resistance and heat transfer efficiency. This parameter control ensures the protective layer is thick enough to prevent corrosion and material diffusion but thin enough to allow effective thermal conduction to the aerosol-forming substrate.
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 improves material savings and reliability by reducing material diffusion and aging, allowing precise temperature control with enhanced corrosion resistance and improved heat transfer to the aerosol-forming substrate.
Implementation Method 1
The device may comprise an induction source for generating an alternating magnetic field used to inductively heat a susceptor arrangement by inducing at least one of eddy currents and hysteresis losses in the material of the susceptor arrangement
Implementation Method 2
The device may comprise an induction source for generating an alternating magnetic field used to inductively heat a susceptor arrangement by inducing at least one of eddy currents and hysteresis losses in the material of the susceptor arrangement
Implementation Method 3
The device may comprise an induction source for generating an alternating magnetic field used to inductively heat a susceptor arrangement by inducing at least one of eddy currents and hysteresis losses in the material of the susceptor arrangement
Implementation Method 4
the second susceptor material is a magnetic (ferro-or ferrimagnetic) material and chosen such as to have a Curie temperature corresponding to a predefined temperature point for heating the substrate. At its Curie temperature, the magnetic permeability of the second susceptor material drops to unity leading to a change of its magnetic properties from ferro-or ferrimagnetic to paramagnetic
Implementation Method 5
At its Curie temperature, the magnetic permeability of the second susceptor material drops to unity leading to a change of its magnetic properties from ferro-or ferrimagnetic to paramagnetic
Implementation Method 6
the third layer may serve as a protective layer configured to at least one of: avoid material diffusion, for example metal migration, from the second susceptor material into the aerosol-forming substrate, or protect other layers, in particular the second layer, from aging, e.g. from corrosive influences
Data Source
AI summary
A multi-layer susceptor arrangement for inductively heating an aerosol-forming substrate is provided, the multi-layer susceptor arrangement including: a first layer including a first susceptor material; a second layer including a second susceptor material; and a third layer including a third material, the second layer being sandwiched between the first layer and the third layer, the second susceptor material including a Ni-Fe-alloy having a Ni content of equal to or smaller than 65 wt %, and a layer thickness of the third layer being equal to or smaller than 20% of a layer thickness of the first layer.