Smoking Article Combustible Heat Source Airflow Channels
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Solution Overview
Problem
Existing heated smoking articles are sensitive to puffing regimes, leading to temperature spikes in the aerosol-forming substrate, which can cause combustion or pyrolysis, and are affected by the migration of aerosol-formers to the combustible heat source, resulting in varying aerosol composition and undesirable by-products.
Innovation Solution
A smoking article design with a combustible heat source having opposed front and rear faces, airflow channels from the front to the rear, and air inlets between the rear face of the heat source and the aerosol-forming substrate, which reduces temperature spikes by introducing cool air and prevents direct contact between air and the heat source, minimizing the impact of puffing regimes and aerosol-former migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If forced convective heat transfer is used to heat the aerosol-forming substrate, then heat transfer efficiency is improved, but temperature stability deteriorates due to sensitivity to puffing regimes
Solution Approach 1:
The airflow path is segmented into two separate channels: one channel provides forced convective heating through the aerosol-forming substrate, while a second channel introduces cool air downstream to stabilize temperature. This segmentation allows independent optimization of heat transfer and temperature control functions.
Solution Approach 2:
Cool air is introduced downstream of the aerosol-forming substrate to preemptively counteract temperature spikes caused by intense puffing regimes. This preliminary anti-action prevents excessive temperature increases before they can cause pyrolysis or combustion.
2Productivity
If air is drawn through the aerosol-forming substrate and into airflow channels, then aerosol generation is improved, but combustion activation occurs under intense puffing regimes
Solution Approach 1:
The airflow system is divided into separate pathways: air drawn through the aerosol-forming substrate follows one path, while cool air introduced through downstream inlets follows another path that prevents combustion activation in the combustible heat source during intense puffing.
Solution Approach 2:
Cool air acts as an intermediary substance introduced downstream to moderate temperature increases and prevent combustion activation of the combustible heat source, while allowing continued aerosol generation through the substrate.
3Productivity
If aerosol-formers migrate to the combustible heat source, then aerosol formation capability is improved, but decomposition occurs leading to undesirable by-products
Solution Approach 1:
The harmful effect of aerosol-former migration and decomposition is extracted and removed by introducing cool air downstream that prevents temperature spikes, thereby eliminating the conditions that cause decomposition and harmful by-product formation.
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 design stabilizes the temperature of the aerosol-forming substrate, preventing combustion or pyrolysis and reducing the variability of aerosol composition, thereby enhancing the consistency and quality of the mainstream aerosol generated.
Implementation Method 1
heat transfer from the combustible heat source to the aerosol-forming substrate occurs by forced convection and conduction
Implementation Method 2
heat transfer from the combustible heat source to the aerosol-forming substrate occurs by forced convection and conduction
Implementation Method 3
cool air drawn through the one or more air inlets reduces the temperature of the aerosol-forming substrate
Implementation Method 4
As the released compounds cool, they condense to form an aerosol that is inhaled by the user
Data Source
AI summary
A smoking article (2, 34, 38, 42, 44, 48) comprises: a combustible heat source (4) having opposed front (6) and rear faces (8); one or more airflow channels (18) extending from the front face (6) to the rear face (8) of the combustible heat source (4); an aerosol-forming substrate (10) downstream of the rear face (8) of the combustible heat source (4); a mouthpiece (14) downstream of the aerosol-forming substrate (10); and one or more air inlets (32, 36) located downstream of the rear face (8) of the combustible heat source (4) and upstream of the mouthpiece (14). The one or more air inlets (32, 36) are located between the rear face (8) of the combustible heat source (4) and a downstream end of the aerosol-forming substrate (10). In use, air drawn through the aerosol-forming substrate (10) enters the smoking article (2, 34, 38, 42, 44, 48) through the one or more airflow channels (18) and the one or more air inlets (32, 36) and at least some of the air drawn through the aerosol-forming substrate (10) comes into direct contact with a combustible portion of the combustible heat source (4).