Filter Element Fold Stabilization Using Thermal Adhesive Winding
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Solution Overview
Problem
Filter elements with zigzag-folded media are prone to denting or buckling due to unstable outer tips, and existing stabilization methods using hot-melt adhesive threads often fail to provide sufficient adhesion, especially under moisture exposure.
Innovation Solution
A filter medium arrangement with a helically wound thread impregnated with hot-melt adhesive, featuring different thread pitches for grip protection and stabilization areas, and thermal means to maintain the adhesive's plastic state for improved adhesion, ensuring radial stabilization and secure handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a thread impregnated with hot melt adhesive is wound onto the filter medium to stabilize the folds, then the radial stability of the filter medium is improved, but the adhesion between the thread and filter medium becomes insufficient under moisture exposure
Solution Approach 1:
The patent applies thermal energy (infrared radiation, hot air, or microwaves) to change the physical state of the hot melt adhesive, maintaining it in a plastic state during winding to enhance penetration and adhesion. This parameter change (temperature control) resolves the contradiction by ensuring reliable adhesion even under moisture exposure while maintaining fold stability
Solution Approach 2:
The patent replaces the conventional mechanical winding process with a thermally assisted winding process. By introducing thermal means (infrared heaters, hot air generators, or microwave sources), the mechanical action of winding is enhanced with thermal energy, allowing the adhesive to remain plastic and penetrate deeper into the filter medium, thus improving adhesion reliability under moisture conditions
2Ease of operation
If the thread pitch is reduced to improve handling protection, then the grip protection capability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent divides the filter medium into different zones with different thread pitch requirements. The handle protection area has a first thread pitch optimized for handling, while other areas have different pitch values. This segmentation allows each zone to be optimized for its specific function without increasing overall manufacturing complexity, as the thermal winding process can accommodate variable pitch requirements
Solution Approach 2:
The patent implements a dynamic thread winding process where the thread pitch can vary along the length of the filter medium. The winding system is designed to adjust pitch dynamically, creating different zones (handle protection area with smaller pitch, other areas with larger pitch). This dynamic approach allows optimization of handling protection in critical areas while maintaining manufacturing efficiency through automated control
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 significantly enhances the stability and adhesion of the filter medium, reducing the risk of thread detachment and improving handling, service life, separation efficiency, and dirt capacity, with increased pull-off force both dry and wet.
Implementation Method 1
the plastic state of the coated thread is maintained by thermal means, wherein the thermal means act on the thread in contact with the fold tips to delay the cooling process
Implementation Method 2
The thermal treatment of the already plastic hot melt adhesive improves its adhesion to the filter fibers and its penetration depth into the medium. This effect is due to the delayed curing of the hot melt adhesive. Thermal action can be achieved, for example, by treatment with heat reflectors, which delay the cooling of the hot melt adhesive.
Data Source
Figure 1~2
AI summary
In a method for stabilizing a folded filter medium (11) using a thread (13), by coating the thread with melt adhesive (16) and winding the thread over the tips (11b) of the folds with the adhesive in a plasticized state, the coated thread is kept in a plasticized condition by heating (18, 19). An independent claim is included for a filter medium strengthened by the process.