Air-Electrospun Nanofiber Filter Medium for Liquid Filtration
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Solution Overview
Problem
Existing liquid filters face issues with low filter efficiency, high energy costs, frequent replacement, and clogging due to thick, two-dimensional porous membranes and uneven pore distribution in calendered nonwovens, which limit their durability and effectiveness, especially in high concentration and turbidity fluids.
Innovation Solution
A filter medium using a nanofiber web with air-electrospun three-dimensional micropores, combining hydrophobic and hydrophilic resins, and a multi-layered structure for depth and surface filtration, achieved through a process of air-electrospinning and high-temperature high-pressure calendering to enhance porosity and flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If porous membranes with two-dimensional closed pore structure are used, then filter efficiency is improved, but filter medium thickness increases and bending becomes difficult
Solution Approach 1:
The patent transitions from two-dimensional closed pore structures to three-dimensional interconnected pore structures by using randomly oriented fibrous materials. This dimensional change allows liquid to flow through the filter medium more easily while maintaining filtration efficiency, eliminating the need for thick filter layers.
Solution Approach 2:
The invention uses fibrous porous materials with specific pore size distributions (micro-pores and macro-pores) to achieve both high filtration efficiency and thin profile. The porous structure allows liquid permeation while trapping contaminants, resolving the contradiction between efficiency and thickness.
2Reliability
If hydrophobic polymer such as PTFE is used in conventional filter, then liquid does not pass through easily, but filter durability is improved
Solution Approach 1:
The filter medium uses a combination of hydrophobic fibers (for structural integrity and durability) and hydrophilic fibers (for liquid wettability and flow). This local quality differentiation allows the filter to maintain durability while enabling liquid passage without excessive pressure requirements.
Solution Approach 2:
The invention employs composite fibrous materials combining hydrophobic and hydrophilic polymers. This composite structure leverages the durability of hydrophobic materials like PTFE while incorporating hydrophilic materials that promote liquid flow, resolving the contradiction between durability and productivity.
3Reliability
If calendered nonwovens with micro fiber size are used, then filter efficiency is improved, but pores become clogged and filter life decreases
Solution Approach 1:
The filter medium is segmented into multiple layers with different pore size characteristics. The upper layer contains finer micro-pores for high filtration efficiency, while the lower layer contains larger macro-pores that prevent clogging and maintain flow. This segmentation allows the filter to achieve both high efficiency and long service life.
Solution Approach 2:
The invention uses a dual-pore structure with both micro-pores (0.1-10 μm) for filtration and macro-pores (10-100 μm) for flow maintenance. This porous material design prevents pore clogging while maintaining high filter efficiency, extending filter life significantly.
4Reliability
If excessive calendering is performed to reduce average pore size, then filter efficiency is improved, but porosity becomes small and filter pressure becomes high
Solution Approach 1:
Different regions of the filter medium have different pore size characteristics. The surface layer has smaller pores for high filtration efficiency, while the bulk structure maintains larger pores for low flow resistance. This local quality variation achieves high efficiency without requiring excessive calendering that would increase pressure drop.
Solution Approach 2:
The invention creates a three-dimensional pore structure with depth-wise variation in pore size. Instead of uniformly reducing pore size through excessive calendering, the structure transitions from finer pores at the surface to coarser pores deeper in the medium, maintaining efficiency while reducing pressure requirements.
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 results in a thin, lightweight filter with high porosity and flow rate, effective impurity removal, and extended lifespan, maintaining filter efficiency and reliability by preventing pore clogging and ensuring consistent performance.
Implementation Method 1
a nanofiber web that is made by stacking nanofibers that are obtained by air-electrospinning a fibrous polymer material and that have micropores
Implementation Method 2
utilize a hydrophobic resin as well as a hydrophilic resin due to capillarity
Data Source
AI summary
Provided is a filter medium for a liquid filter, having a three-dimensional micropore structure of a multi-layered structure using a multilayer nanofiber web that is obtained by performing air-electrospinning, to thus be thin but have high efficiency and long life, a method of manufacturing the filter medium using the multilayer nanofiber web, and a liquid filter using the filter medium. The filter medium for a liquid filter, includes: a nanofiber web that is made by stacking nanofibers that are obtained by air-electrospinning a fibrous polymer material and that have micropores; and a supporter that is inserted and combined onto one surface or in an inner portion of the nanofiber web.