Insulated Heat Source for Smoking Articles

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Solution Overview

Problem

Heated smoking articles with combustible carbon-containing heat sources often have high ignition propensity and complex assembly, affecting appearance and reliability, while also requiring consistent aerosol production during both early and late puffs.

Innovation Solution

A heat source with a combustible carbonaceous core and an integral, non-combustible, thermally insulating peripheral layer, where the peripheral layer extends only part way along the length to reduce ignition propensity and ensure reliable assembly, combined with a heat-conducting, combustion-resistant wrapper for efficient heat transfer to the aerosol-forming substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a combustible carbon-containing heat source is used in a heated smoking article, then sufficient heat is generated to release volatile compounds from the aerosol forming material, but the ignition propensity becomes unacceptably high

Engineering Contradiction:

Improveheat generation capabilityVSAvoidignition propensity

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The heat source is segmented into a combustible core and a separate insulating layer. The insulating layer is applied only to specific portions of the core (e.g., upstream portion or circumferential surface), rather than completely encapsulating it. This partial segmentation reduces ignition propensity at exposed surfaces while preserving heat generation capability in the combustible core.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the heat source are given different thermal properties. The combustible core maintains high thermal conductivity for heat generation, while selected regions are covered with thermally insulating material to reduce ignition propensity. This local differentiation allows simultaneous optimization of both heat generation and safety.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If an insulating member is wrapped around the periphery of a combustible carbon-containing heat source, then ignition propensity is reduced, but the appearance becomes unacceptable and assembly becomes complex

Engineering Contradiction:

Improveignition propensityVSAvoidassembly complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The insulating layer is integrated directly with the combustible core to form a single unified heat source component. This merging eliminates the need for separate assembly steps involving multiple components (insulating member, heat source, holder), thereby simplifying assembly while maintaining the insulating function to reduce ignition propensity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The insulating layer serves multiple functions simultaneously: it reduces ignition propensity, provides structural support, and contributes to the overall shape and appearance of the heat source. This multi-functionality eliminates the need for separate components, simplifying both assembly and design.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If an insulating member is wrapped around the periphery of a combustible carbon-containing heat source, then ignition propensity is reduced, but the appearance becomes unacceptable

Engineering Contradiction:

Improveignition propensityVSAvoidappearance

Core Design Contradiction:

Object-affected harmful factorsVSShape

Solution Approach 1:

The insulating layer is applied selectively to specific regions of the combustible core rather than completely enclosing it. This local application reduces ignition propensity in critical areas while leaving other surfaces exposed to maintain an acceptable appearance and constant transverse cross-section.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The insulating layer is formed as an integral copy or extension of the combustible core's structure, taking on the same shape and dimensions. This ensures that the overall external geometry remains uniform and aesthetically acceptable, while the insulating function is provided in the necessary regions.

Inventive Principle:

Principle #26Copying

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 reduces ignition propensity, maintains an acceptable appearance, and ensures consistent aerosol production by controlling heat transfer effectively, addressing the challenges of high ignition propensity and assembly complexity.

Implementation Method 1

an integral, non-combustible, thermally insulating, peripheral layer

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

a heat-conducting, combustion-resistant wrapper around and in direct contact with an upstream portion of the aerosol-forming substrate and a downstream portion of the core

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS10779569B2Insulated heat source

Publication Date: 2020.09.22 PHILIP MORRIS PRODUCTS SA

AI summary

There is provided a heat source for a smoking article, including an upstream end and an opposed downstream end, and further including a combustible carbonaceous core and an integral, non-combustible, thermally insulating, peripheral layer. The core extends from the upstream end of the heat source the downstream end of the heat source. The peripheral layer extends from the upstream end of the heat source only part way along the length of the heat source and circumscribes an upstream portion of the core.