Wrapper Projections for Heat Source Retention in Smoking Articles

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Solution Overview

Problem

Existing heated smoking articles face challenges in retaining the combustible heat source effectively while maintaining sufficient conductive heat transfer to the aerosol-forming substrate, leading to inconsistent aerosol delivery due to temperature fluctuations.

Innovation Solution

A smoking article design featuring a wrapper with inwardly extending projections covering between 10% and 70% of the inner surface area over the combustible heat source, which helps retain the heat source and ensure consistent heat transfer to the aerosol-forming substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If axial projections are provided on only a small portion of the inner surface of the holder part and are of considerable height, then the holder part can more reliably hold the carbon heat source, but air gaps between the remainder of the inner surface and the carbon heat source adversely affect conductive heat transfer

Engineering Contradiction:

Improveretention of combustible heat sourceVSAvoidconductive heat transfer

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The wrapper surface is designed with non-uniform properties: projections are provided on only a portion of the inner surface rather than uniformly across the entire surface. This allows the surface to have different local characteristics - areas with projections for retention and areas without projections for heat transfer - thereby resolving the contradiction between reliable heat source retention and effective conductive heat transfer.

Inventive Principle:

Principle #3Local quality

2Reliability

If the temperature of the aerosol-forming substrate drops outside of a desired range due to movement of the combustible heat source, then the consistency and amount of aerosol delivered to a user are adversely impacted

Engineering Contradiction:

Improveaerosol delivery consistencyVSAvoidtemperature of aerosol-forming substrate

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The projections on the wrapper provide preliminary mechanical anchoring of the combustible heat source before use. This preliminary retention action prevents movement during the aerosol-generating process, thereby maintaining consistent temperature at the aerosol-forming substrate and ensuring reliable aerosol delivery consistency.

Inventive Principle:

Principle #10Preliminary action

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 enhances the retention of the combustible heat source and maintains optimal temperature for the aerosol-forming substrate, improving the consistency and quantity of aerosol delivery to the user.

Implementation Method 1

a plurality of inwardly extending projections are provided on an inner surface of the wrapper overlying the combustible heat source

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

the plurality of inwardly extending projections cover between about 10 percent and about 70 percent of the surface area of the inner surface of the wrapper overlying the combustible heat source

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 3

maintains optimal temperature for the aerosol-forming substrate, improving the consistency and quantity of aerosol delivery

Methodology Applied

Scientific EffectConduction (thermal): Conduction (thermal)

Implementation Method 4

During smoking, volatile compounds are released from the aerosol-forming substrate by heat transfer from the combustible heat source and entrained in air drawn through the smoking article. As the released compounds cool, they condense to form an aerosol that is inhaled by the user.

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 5

entrained in air drawn through the smoking article

Methodology Applied

Scientific EffectPressure Gradient: Pressure Gradient

Data Source

PatentUS10595558B2Smoking article comprising a wrapper with a plurality of projections provided on an inner surface thereof

Publication Date: 2020.03.24 PHILIP MORRIS PRODUCTS SA

AI summary

A smoking article is provided, including a combustible heat source; an aerosol-forming substrate downstream of the combustible heat source; and a wrapper circumscribing at least a rear portion of the combustible heat source and at least a front portion of the aerosol-forming substrate, wherein a plurality of inwardly extending projections are disposed on an inner surface of the wrapper overlying the combustible heat source, and the plurality of inwardly extending projections cover between about 10 percent and about 70 percent of a surface area of the inner surface of the wrapper overlying the combustible heat source.