Irregular Structure Filter Media for Low Pressure Drop
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Solution Overview
Problem
Conventional filter media often face a trade-off between high efficiency and low resistance to fluid flow, resulting in higher pressure drops, which limits their application in various filtration processes.
Innovation Solution
A filter media with an irregular structure is developed, comprising a non-woven fiber web with specific surface height and peak characteristics, formed by depositing layers onto a reversibly stretched layer that recovers to create undulated peaks, enhancing surface area and basis weight while maintaining low stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If filter media uses conventional structure with high surface area to achieve high filtration efficiency, then filtration efficiency is improved, but resistance to fluid flow increases leading to higher pressure drops
Solution Approach 1:
The patent introduces an irregular three-dimensional structure with peaks and valleys that extends the filter media surface into the third dimension. This dimensional transformation increases the effective filtration surface area without proportionally increasing the footprint area, allowing more filtration surface to be packed into the same space while maintaining lower resistance to fluid flow through the structured voids between peaks
Solution Approach 2:
The patent changes the physical parameters of the filter media by creating an irregular structure with specific peak height distributions (standard deviation to mean ratio ≥ 0.05) and surface height characteristics (average surface height > 0.3 mm). These parameter changes optimize the balance between filtration efficiency and pressure drop by controlling the distribution of peak heights and spacing
2Reliability
If filter media increases surface area through irregular structure, then gamma value is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs a self-assembling approach where particles are deposited onto a stretchable substrate that is then relaxed. The substrate's elastic recovery automatically generates the irregular peak structure without requiring complex external molding or shaping tools. This self-service mechanism transforms a potentially complex manufacturing process into a simpler, more scalable operation
Solution Approach 2:
The patent performs preliminary stretching of the substrate before particle deposition. This preliminary action creates a temporary flat surface that simplifies the deposition process, and the subsequent relaxation automatically forms the desired irregular structure. By preparing the substrate in advance with opposite characteristics (stretched flat), the final desired structure (irregular peaks) is achieved through a simple relaxation step
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 irregular structure filter media achieves a high gamma value, indicating improved filtration efficiency with reduced pressure drop, making it suitable for diverse applications including HVAC and respiratory protective equipment.
Implementation Method 1
The second layer is formed from a reversibly stretchable material. The first layer is held in an undulated configuration by the second layer.
Implementation Method 2
A fiber web provides a porous structure that permits fluid (e.g., gas, air) to flow through the filter media. Contaminant particles contained within the fluid may be trapped on or within the fibrous web.
Implementation Method 3
The irregular structure may include an irregular conformation (e.g., spatial conformation, surface conformation) of at least a portion of one or more layers in the filter media. The filter media may comprise a plurality of peaks irregular in one or more ways.
Data Source
AI summary
Articles and methods relating to filter media are generally provided. In some embodiments, a filter media has an irregular surface structure. For instance, the filter media may comprise a plurality of peaks that are irregular in one or more ways. A ratio of a peak height standard deviation to an average peak height may be greater than or equal to 0.05, and/or a ratio of a peak spacing standard deviation to an average peak spacing may be greater than or equal to 0.08. In some embodiments, a filter media comprises a non-woven fiber web having a layer thickness of greater than 0.3 mm and/or a stiffness of less than or equal to 100 mg.