Smoking Article Flow Restriction Element for Draw and CO Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Cigarettes with low permeability wrappers reduce sidestream smoke but increase carbon monoxide yields and carbon monoxide to tar ratios in mainstream smoke, while high ventilation levels compromise resistance to draw and have limited effect on these ratios.
Innovation Solution
A smoking article featuring a flow restriction element with a first and second tubular portion of the same external diameter and a central tubular portion of reduced diameter, along with a transverse barrier and ventilation zone, which maintains an acceptable carbon monoxide to tar ratio and resistance to draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a low permeability wrapper is used to reduce sidestream smoke, then sidestream smoke is reduced, but carbon monoxide yields and carbon monoxide to tar ratios increase
Solution Approach 1:
The filter is divided into multiple segments with different functions: a first filter segment for initial filtration, a flow restriction element with specific geometry to control gas flow and pressure drop, and a second filter segment for additional filtration. This segmentation allows each component to address specific aspects of the contradiction independently.
Solution Approach 2:
Different portions of the filter have different properties optimized for their specific functions. The flow restriction element has a reduced diameter central portion to create backpressure, while the filter segments have high surface area for filtration. The low permeability wrapper is applied locally to the tobacco rod to reduce sidestream smoke without affecting the entire article's flow characteristics.
2Object-generated harmful factors
If high levels of ventilation are used to reduce carbon monoxide and tar deliveries, then carbon monoxide and tar deliveries are reduced, but resistance to draw becomes unacceptably low
Solution Approach 1:
The flow restriction element's geometry is specifically designed with a reduced diameter central portion to create an optimal balance between ventilation and resistance to draw. The dimensions and configuration of this restricted portion are controlled to provide sufficient backpressure while allowing adequate ventilation to reduce harmful deliveries.
3Force
If high density cellulose acetate filter segments are used to increase resistance to draw, then resistance to draw increases, but tar deliveries are reduced with little effect on carbon monoxide deliveries
Solution Approach 1:
The filter uses multiple segments with different densities and functions. Rather than relying on a single high density segment, the combination of flow restriction element and multiple filter segments creates a more effective system for controlling both resistance to draw and the composition of delivered smoke.
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 solution effectively produces highly ventilated smoking articles with a carbon monoxide to tar ratio of less than or equal to 1, even with sidestream smoke reducing wrappers, while maintaining acceptable resistance to draw and being manufacturable using existing equipment.
Implementation Method 1
A ventilation zone in communication with the second cavity is provided at a location along the filter
Implementation Method 2
A transverse barrier having at least one orifice provided therein is disposed between a first upstream cavity at least partially defined by an inner periphery of the first tubular portion and a second downstream cavity at least partially defined by an inner periphery of the second tubular portion
Implementation Method 3
cigarettes and other smoking articles with wrappers having a low permeability in order to reduce the sidestream smoke generated during smoking thereof
Data Source
Figure 1~2
Figure 3~5
AI summary
A smoking article (10) comprises: a rod of smokable material (12); and a filter (14) comprising a flow restriction element (26, 26') attached to the rod of smokable material (12). The flow restriction element (26, 26') comprises: a first upstream integral tubular portion (30, 30'); a second downstream integral tubular portion (32, 32') of substantially the same external diameter as the first tubular portion (30, 30'); and a third central integral tubular portion (34, 34') located between the first and second tubular portions (32, 32', 34, 34'), the third tubular portion (34, 34') being of reduced external diameter compared to the first and second tubular portions (30, 30', 32, 32'). A transverse barrier (36, 36') having at least one orifice (38, 38') provided therein is disposed between a first upstream cavity (40, 40') at least partially defined by an inner periphery of the first tubular portion (30, 30') and a second downstream cavity (42, 42') at least partially defined by an inner periphery of the second tubular portion (32, 32'). A ventilation zone in communication with the second cavity (42, 42') is provided at a location along the filter (14).