Tobacco Casting Web Temperature Control
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Solution Overview
Problem
Existing methods for producing cast webs of homogenized tobacco material often result in inhomogeneities due to variations in slurry consistency, viscosity, and temperature, leading to defects such as tearing and inconsistent aerosol delivery in 'heat-not-burn' aerosol-generating articles.
Innovation Solution
An apparatus with a casting box, a movable support with temperature control, and a drum for heat exchange, which maintains a temperature difference between the slurry and the support between 0°C and 30°C, ensuring uniform temperature distribution and minimizing thermal shocks during the casting process, along with controlled drying sections to optimize moisture removal and prevent crust formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If standard casting methods are used without temperature control, then the casting process is simple, but inhomogeneity and defects occur in the cast web due to temperature variations in the slurry
Solution Approach 1:
The patent applies parameter changes by controlling the temperature of the drum and movable support within specific ranges (drum: 10-50°C, support: 15-40°C) to maintain slurry temperature stability. This prevents thermal shocks and ensures homogeneous cast web formation, directly addressing the inhomogeneity issue while implementing a manageable temperature control system.
Solution Approach 2:
The patent implements feedback control through temperature sensors that continuously monitor the slurry, drum, and movable support temperatures. The control system adjusts heating or cooling based on real-time temperature readings, ensuring the temperature difference remains within the optimal 0-30°C range and preventing defects in the cast web.
2Productivity
If the temperature difference between slurry and support is large, then casting speed can be increased, but thermal shocks cause inhomogeneity and defects in the cast web
Solution Approach 1:
The patent applies preliminary action by pre-heating or pre-cooling the movable support and drum to their target temperatures before casting begins. This ensures that when slurry is applied, the temperature difference is already controlled within the optimal range, preventing thermal shocks and allowing sustained casting speed without compromising homogeneity.
Solution Approach 2:
The patent dynamically adjusts the temperature parameters of the drum and movable support based on the slurry temperature and casting conditions. By maintaining the temperature difference within 0-30°C, the system optimizes both casting speed and web homogeneity, resolving the contradiction between productivity and manufacturing precision.
3Productivity
If drying is performed at high temperature to remove moisture quickly, then productivity increases, but crust formation occurs on the cast web surface
Solution Approach 1:
The patent segments the drying process into multiple stages with different temperature profiles. The first drying section operates at moderate temperatures to remove surface moisture without crust formation, while subsequent sections gradually increase temperature for deeper moisture removal. This staged approach maintains surface quality while achieving efficient overall drying.
Solution Approach 2:
The patent implements periodic action through alternating heating and cooling cycles during the drying process. This prevents continuous high-temperature exposure that causes crust formation, while still achieving effective moisture removal over time. The periodic temperature variations allow moisture to escape without forming a crust barrier.
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 apparatus produces a homogeneous cast web with high tensile strength and minimized defects, ensuring consistent aerosol delivery and improved manufacturing efficiency by maintaining optimal slurry viscosity, density, and moisture levels.
Implementation Method 1
the drum is adapted to allow heat exchange between said drum and said movable support
Implementation Method 2
a first drying section adapted to dry said cast web
Data Source
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AI summary
The invention relates to an apparatus (1) for the production of cast web of homogenized tobacco material, said casting system comprising - a casting box (4) adapted to contain a slurry of said homogenized tobacco material and from which a cast web of said slurry is cast; - a first drying section (21) adapted to dry said cast web; - a movable support (7) to receive the cast web formed by casting said slurry from said casting box and to transport it to said first drying section; - a drum (8) adapted to move said movable support and adapted to allow heat exchange between said drum and said movable support; and - first temperature control means (80) to cool said drum (8) so that a temperature difference between a temperature of said movable support (7) at a position where said cast web is received onto said support (7) from said casting box (4) and a temperature of said slurry in said casting box is comprised between about 0 degree Celsius and about 30 degrees Celsius.