Metallic Heater Element with Surface Notches for Aerosol Devices

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Solution Overview

Problem

Existing aerosol-generating device heater elements face issues with residue buildup, which hinders heat conduction and imparts unwanted flavors, and are prone to fracturing due to brittleness and overheating from high thermal conductivity materials.

Innovation Solution

A metallic heater element with a plurality of surface notches and sub-surface cavities is designed to manage heat flow and enhance thermal protection, while maintaining sufficient flexural rigidity to withstand operational and cleaning forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a ceramic substrate is used for the heater element, then the heater element can withstand cleaning forces without fracturing, but heat conduction is hindered due to residue buildup

Engineering Contradiction:
Improveresistance to fracturingVSAvoidheat conduction hindrance
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention changes the material parameter from ceramic to metallic, fundamentally altering the thermal conductivity and mechanical properties. This allows the heater element to maintain structural integrity during cleaning while enabling effective heat conduction to the aerosol-forming substrate, resolving the contradiction between fracture resistance and heat transfer capability.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a metallic substrate is used for the heater element, then the likelihood of fracturing is reduced, but excessive temperatures are conducted to control circuitry due to high thermal conductivity

Engineering Contradiction:
Improveresistance to fracturingVSAvoidsubstrate temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The invention applies local quality by creating regions of different thermal conductivity within the metallic substrate through selective notching. The notched regions have reduced thermal conductivity compared to solid metal, allowing the substrate to maintain mechanical durability while preventing excessive heat conduction to sensitive control circuitry. This localized modification of thermal properties resolves the contradiction between fracture resistance and temperature control.

Inventive Principle:
Principle #3Local quality

3Strength

If the heater element is made from metallic material, then ductility is improved, but heat is rapidly conveyed throughout the substrate leading to overheating

Engineering Contradiction:
ImproveductilityVSAvoidheat energy loss
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The selective notching creates a non-uniform thermal conductivity distribution within the metallic substrate. Regions with notches have lower thermal conductivity, acting as thermal barriers that prevent rapid heat propagation throughout the entire substrate. This local modification maintains the inherent ductility of metallic materials while reducing overall heat energy loss through the substrate, resolving the contradiction between strength and energy loss.

Inventive Principle:
Principle #3Local quality

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 effectively reduces heat transfer rates, prevents overheating, and increases the durability of the heater element by minimizing the risk of fracturing, thereby enhancing user experience and device performance.

Implementation Method 1

electrically-powered heater elements are known which generate heat by resistive heating under the action of an electric current

Methodology Applied
Scientific EffectResistive heating: Joule Heating

Implementation Method 2

the relatively higher thermal conductivity of the metallic substrate can lead to heat conducted into the substrate from the resistive heating track being rapidly conveyed throughout the metallic substrate

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4297597B1Heater element and method of manufacturing a heater element
Publication Date: 2025.04.02 PHILIP MORRIS PRODUCTS SA
  • EP4297597B1 patent drawingFigure 1
  • EP4297597B1 patent drawingFigure 2a
  • EP4297597B1 patent drawingFigure 2b

AI summary

An elongate metallic heater element (40) for use with an aerosol-generating device (20) is disclosed. The heater element extends between a proximal end (44) and a distal end (45). The proximal end is configured for mounting to an aerosol-generating device for electrical communication with the aerosol-generating device. The heater element has either or both of a plurality of surface notches (48) formed on a surface of the heater element and a plurality of sub-surface cavities (480) defined beneath the surface of the heater element.