Thermal Indicator with Reversible Thermochromic Material
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Solution Overview
Problem
Aerosol-generating articles with combustible carbonaceous heat sources often remain too hot after use, making it difficult for users to determine when they are extinguished, which poses a risk for disposal and proper handling.
Innovation Solution
Incorporating a thermal indicator with reversible thermochromic materials on the outer surface downstream of the combustible carbonaceous heat source, which undergoes visible color changes at specific temperature thresholds, providing a visual indication when the heat source has cooled sufficiently for safe disposal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a combustible carbonaceous heat source is used to generate aerosol, then aerosol generation is achieved, but the heat source remains hot after use making it difficult to determine when it is extinguished
Solution Approach 1:
The patent applies a thermal indicator comprising thermochromic material that changes color in response to temperature changes. The indicator transitions from a first color when the heat source is hot to a second color when cooled to a safe temperature, providing visual feedback to users about the heat source status without affecting aerosol generation.
2Duration of action of moving object
If the combustible carbonaceous heat source remains hot after use, then aerosol generation function is maintained, but user safety is compromised due to inability to detect when the device is safe for disposal
Solution Approach 1:
The thermal indicator provides visual feedback to users about the temperature status of the heat source. By observing the color change of the indicator, users can determine when the heat source has cooled to a safe temperature for disposal, eliminating the uncertainty and safety hazard associated with handling a potentially hot device.
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 thermal indicator effectively signals to the user when the aerosol-generating article has cooled to a safe temperature for disposal, enhancing user safety and proper handling by providing a visual cue for when the device is ready to be discarded.
Implementation Method 1
the thermal indicator comprises at least one reversible thermochromic material that undergoes a first reversible visible colour change when the temperature of the thermal indicator rises to a first switching temperature
Implementation Method 2
a second reversible visible colour change when the temperature of the thermal indicator falls to a second switching temperature
Data Source
AI summary
An aerosol generating article is provided, including a combustible carbonaceous heat source; an aerosol-forming substrate; and a thermal indicator provided on an outer surface of the aerosol-generating article downstream of the combustible carbonaceous heat source. The thermal indicator includes at least one reversible thermochromic material that undergoes a first reversible visible colour change when a temperature of the thermal indicator rises to a first switching temperature and a second reversible visible colour change when a temperature of the thermal indicator falls to a second switching temperature. The first switching temperature is below about 80° C. and the second switching temperature is lower than or equal to the first switching temperature.