Aerosol Filter Rod Structure for Filtration and Draw Resistance
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Solution Overview
Problem
Aerosol generating articles that heat aerosol forming substrates without burning them face challenges in balancing filtration efficiency, resistance to draw, structural rigidity, compressibility, and resistance to wetting, particularly due to the higher inherent resistance provided by sensory media and the use of materials like cellulose acetate and PLA sheets.
Innovation Solution
An aerosol permeation element comprising an aerosol permeable core surrounded by a sleeve, where the sleeve consists of linear, axially oriented fibres and the core comprises expanded, randomly oriented fibres, with the sleeve segments bonded along longitudinal edges to form an integral structure, using materials like cellulose acetate, poly lactic acid, or other fibres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensory media is more closely packed to enhance sensory experience, then the filtration efficiency is improved, but the resistance to draw increases significantly
Solution Approach 1:
The filter rod employs different fibre orientations in different regions: the sleeve contains linear axially oriented fibres for low resistance to draw, while the core contains expanded randomly oriented fibres for high filtration efficiency. This local differentiation allows each region to optimise its function without compromising the other.
2Strength
If the filter part structure is made more rigid to withstand consumer compressive forces, then the structural integrity is improved, but the resistance to draw increases
Solution Approach 1:
The sleeve region is designed with linear axially oriented fibres that provide structural rigidity to withstand consumer handling and compressive forces, while the core region uses expanded random fibres that maintain low resistance to aerosol flow. This spatial differentiation of fibre orientations resolves the contradiction between strength and flow resistance.
3Reliability
If the filter part is made more resistant to wetting to prevent saliva transmission, then the protection function is improved, but the manufacturing complexity increases
Solution Approach 1:
The filter rod materials themselves (cellulose acetate and PLA) inherently provide resistance to wetting and saliva transmission without requiring additional coating layers or complex surface treatments. The material selection alone satisfies the wetting resistance requirement, simplifying the manufacturing process.
4Strength
If wrapping paper is used to provide resistance to consumer mouth pressure, then the structural strength is improved, but the ease of shaping deteriorates and taste impact increases
Solution Approach 1:
The filter rod uses a composite structure of cellulose acetate and PLA fibres in specific orientations. This composite material approach provides the necessary mechanical strength to resist mouth pressure while maintaining flexibility for shaping, eliminating the need for hard wrapping paper that is difficult to shape and can impact taste.
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 achieves a balanced performance in filtration, resistance to draw, structural integrity, and resistance to wetting, while allowing for consumer interaction and sensory enhancement through additives, providing a versatile and effective aerosol permeation solution.
Implementation Method 1
The main role of the filter part is filtration efficiency, namely its effectiveness in removing unwanted components of the aerosol
Implementation Method 2
the tow material of the longitudinal segments is bonded together at least along longitudinal edges of the segments to form an integral sleeve
Implementation Method 3
the overall resistance to draw, which is the pressure drop experienced as the aerosol passes through the filter
Implementation Method 4
The filter part must also continue to function despite exposure to the saliva of a consumer and should minimise or prevent its transmission therethrough to avoid wetting of the aerosol forming substrate
Data Source
Figure 1~3
Figure 4~6
Figure 7
AI summary
A filter part(1) for use in an aerosol generating article and a method of manufacturing the filter part (1). The filter part (1) includes an aerosol permeable core (11) surrounded by a sleeve (12). The sleeve (12) is formed of linear, axially oriented fibres and the core (11) is formed of expanded, randomly oriented fibres. The method includes forming two or more strips (2a, 2b) into segments surrounding a conveying path, bringing the segments together into a sleeve former (7) to form the sleeve (12) and introducing loose fibres (52) between the segments upstream of the sleeve former (7) such that they are drawn therein in a random orientation and compressed between the segments as they are brought together to form a filter rod (8) with an aerosol permeable core (11) within the sleeve (12).The filter rod (8) is then cut to form the filter part (1).