Pleated Filter Tridirectional Scrim Stability
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Solution Overview
Problem
Conventional bidirectional scrims on pleated filters fail to effectively resist expansive deformation under airstream pressure, as the second set of filaments does not contribute significantly to stability, and their orientation can compromise the alignment of the first set of filaments perpendicular to the pleat direction, leading to decreased stability and aesthetic issues.
Innovation Solution
A tridirectional scrim is used, with filaments oriented in a planar configuration, where a first set is perpendicular to the pleat direction, and second and third sets extend across multiple pleats, providing additional resistance to expansive deformation and maintaining optimal alignment for stability and aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bidirectional scrim is used on pleated filters, then manufacturing is simplified, but stability against expansive deformation deteriorates
Solution Approach 1:
The patent transitions from bidirectional (2-directional) scrim to tridirectional (3-directional) scrim, adding another dimension of filament orientation. The third set of filaments is oriented at approximately 45 degrees to the first and second sets, creating a three-dimensional network that provides resistance to expansive deformation in multiple directions, thereby resolving the contradiction between manufacturing simplicity and stability.
2Area of stationary object
If second set of filaments is added in bidirectional scrim, then coverage is improved, but alignment of first set perpendicular to pleat direction deteriorates
Solution Approach 1:
The patent segments the scrim structure into three distinct sets of filaments, each oriented in a specific direction. The first set is perpendicular to the pleat direction, the second set is parallel to the pleat direction, and the third set is at approximately 45 degrees. This segmentation allows each set to perform its specific function independently, with the first set maintaining precise perpendicular alignment while the other sets provide additional coverage and stability.
3Stability of the object's composition
If tridirectional scrim is used, then stability against expansive deformation is improved, but device complexity increases
Solution Approach 1:
The patent changes the structural parameters of the scrim by adding a third set of filaments oriented at approximately 45 degrees to the first and second sets. This parameter change (adding one more orientation direction) provides significant improvement in stability against expansive deformation. The complexity increase is managed by using a regular, repeating geometric pattern that can be manufactured using standard textile processes.
Data Source
AI summary
Herein is disclosed a pleated filter comprising an upstream face and a downstream face and comprising at least one flexible inextensible tridirectional scrim in discontinuous contact with the downstream face of the pleated filter and bonded to the pleat tips of the downstream face of the pleated filter. In additional embodiments, an additional tridirectional scrim may be provided in discontinuous contact with the upstream face of the pleated filter and bonded to the pleat tips of the upstream face of the pleated filter. In further embodiments, at least one continuous, substantially nonlinear adhesive strand may be provided on at least one face of the pleated filter.