Nanofiber Filter Medium with Electrospun Pore Control
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Solution Overview
Problem
Conventional filter media, such as nonwovens and porous membranes, face challenges in creating uniform fine pores smaller than 1 μm, leading to low filter efficiency and leakage due to large pore sizes, and existing solutions like alumina composite nonwovens suffer from low filtering efficiency and high operating costs.
Innovation Solution
A filter medium is developed by laminating a nanofiber web formed through electrospinning on both sides of a porous substrate using a thermally fusing structure or hot-melt adhesive, allowing for precise control of pore size and enhancing filter efficiency, with the nanofiber web being made of polyvinylidene fluoride (PVdF) or a mixture with polyacrylonitrile (PAN).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional nonwovens, wovens, or meshes are used as filter media, then the structure is simple and ease of manufacture is good, but the pore size is large (not less than 1 μm) and uniformity is poor, resulting in low filter efficiency
Solution Approach 1:
The patent changes the fiber diameter parameter from micrometer scale (several μm to hundreds of μm) to nanometer scale (10-500 nm) through electrospinning technology. This parameter change enables pore sizes below 1 μm while maintaining manufacturability, as the electrospinning process can precisely control fiber diameter and resulting pore size, achieving uniform fine pores that conventional methods cannot produce
Solution Approach 2:
The patent replaces conventional mechanical filtration methods (melt-blown, weaving, knitting) with electrospinning technology. Instead of using mechanical forces to form fibers and pores, the invention uses electrostatic forces to draw polymer solutions into ultrafine fibers, creating a nonwoven fabric with controlled nanoscale pores that cannot be achieved through traditional mechanical processes
2Manufacturing precision
If melt-blown nonwoven fabric is used, then the manufacturing process is simple, but the pore size deviation is large (±20% or more) and very large pores coexist, leading to low filtering precision
Solution Approach 1:
The patent changes the fiber diameter from micrometer scale to nanometer scale (10-500 nm) through electrospinning, which fundamentally alters the pore size distribution. The nanoscale fibers create uniformly small pores without the large pore deviations (±20% or more) seen in melt-blown fabrics, achieving pore sizes consistently below 1 μm that eliminate the coexistence of very large and small pores
Solution Approach 2:
The electrospinning process creates locally uniform fiber mat structures where each region possesses consistent nanoscale pore characteristics. The random arrangement of ultrafine fibers produces a homogeneous pore distribution throughout the filter medium, ensuring uniform filtration performance across the entire surface without the pore size variations that plague conventional nonwovens
3Manufacturing precision
If porous membranes are used to achieve precise small pores, then filter efficiency is improved, but the membrane thickness cannot be reduced and system size remains large
Solution Approach 1:
The patent changes the fundamental structure from dense thick membranes to thin nonwoven fabrics with nanoscale pores. The electrospun nonwoven fabric achieves precise pore size control (below 1 μm) through nanometer-scale fiber diameters (10-500 nm) while maintaining a thin profile, eliminating the need for thick membrane structures required by conventional porous membranes to achieve the same filtration precision
4Productivity
If conventional filter media with large pores are used, then the flow rate is high, but filter efficiency is low and contaminated materials leak through
Solution Approach 1:
The patent changes the pore size parameter from micrometer scale to sub-micrometer scale (below 1 μm) through nanoscale fiber construction. The electrospun nonwoven fabric with 10-500 nm fibers creates pores small enough to prevent leakage of contaminated materials while maintaining high flow rates through the interconnected pore network, achieving both high productivity and high filtration precision simultaneously
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 approach improves filter endurance, reduces system size by making thin filter plates, and enhances handling and strength, achieving better filter efficiency and reducing the need for frequent filter replacements.
Implementation Method 1
a nanofiber web that is laminated on both sides of the porous substrate, and that has a number of fine pores formed by electrospinning a polymer material
Implementation Method 2
an adhesive unit for adhering the porous substrate and the nanofiber web integrally, wherein the adhesive unit has a thermally fusing structure that is achieved by applying heat whose temperature is lower than the melting point of the porous substrate and higher than the melting point of the nanofiber web
Data Source
AI summary
A filter medium includes: a porous substrate; a nanofiber web laminated on both surfaces of the porous substrate, the nanofiber web being formed of accumulated nanofibers made of a polymer material and having a number of fine pores; and a fuse reinforcement material interposed between the nanofiber web and the porous substrate for adhesion with the nanofiber web and the porous substrate integrally. The porous substrate is surrounded by the nanofiber web except for an upper edge of the porous substrate, the upper edge of the porous substrate protrudes with respect to the nanofiber web to form a protruding portion, and the protruding portion is configured to be connected with a discharge hole through which purified water via the porous substrate is discharged.