Dual Heat-Conducting Elements for Radiative Loss Reduction
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Solution Overview
Problem
Heated smoking articles face challenges in maintaining the temperature of the aerosol-forming substrate within a desired range due to radiative heat losses, which can impact aerosol generation and delivery, especially when convective heating is minimal.
Innovation Solution
Incorporating a second heat-conducting element radially separated from the first heat-conducting element to reduce conductive heat transfer and enhance radiative heat retention, thereby maintaining the temperature of the aerosol-forming substrate and improving aerosol delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a first heat-conducting element is provided around the heat source and aerosol-forming substrate, then conductive heat transfer is improved, but radiative heat losses increase causing temperature drop
Solution Approach 1:
A second heat-conducting element is provided around the first heat-conducting element, creating a nested configuration. The second element acts as an additional thermal barrier that reduces radiative heat losses from the first element, thereby maintaining the temperature of the aerosol-forming substrate without requiring increased conductive heating
2Productivity
If the aerosol-forming substrate is heated primarily by conductive heat transfer, then heating efficiency is improved, but temperature becomes more sensitive to changes in heat-conducting element temperature
Solution Approach 1:
The invention changes the thermal parameters of the system by adding a second heat-conducting element with different thermal properties. This second element modifies the overall heat transfer characteristics, reducing the sensitivity of the aerosol-forming substrate temperature to variations in the first heat-conducting element's temperature while maintaining efficient heating
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 second heat-conducting element helps maintain the temperature of the aerosol-forming substrate within the desired range, enhancing aerosol generation and nicotine delivery, while extending smoking duration and improving puff-by-puff consistency.
Implementation Method 1
The heat-conducting element in the smoking article of WO-A-2009/022232 transfers the heat generated during combustion of the heat source to the aerosol-forming substrate via conduction
Implementation Method 2
radiative heat losses from the outer surface of the heat-conducting element may cause the temperature of the combustible heat source and the aerosol-forming substrate to drop outside of the desired range
Implementation Method 3
convective heat transfer from a combustible heat source to the aerosol-forming substrate is provided in addition to the conductive heat transfer
Data Source
AI summary
A smoking article is provided, including a heat source; an aerosol-forming substrate downstream of the heat source; a first heat-conducting element around and in contact with a rear portion of the heat source and an adjacent front portion of the aerosol-forming substrate; and a second heat-conducting element around at least a portion of the first heat-conducting element. At least part of the second heat-conducting element is radially separated from the first heat-conducting element; and, preferably, the first and second heat-conducting elements are separated by an outer paper wrapper.