Stable Nanofiber Filter Media for Liquid Filtration
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Solution Overview
Problem
Conventional filter media face challenges in achieving high particulate efficiency, permeability, and structural stability under various conditions such as high temperature, high pressure, and steam sterilization, often requiring trade-offs between these properties.
Innovation Solution
A filter media comprising a first nanofiber web with an average fiber diameter of less than or equal to 0.5 microns and a second fiber web with a maximum pore size of 3 to 70 microns, where the critical wetting surface tensions of both webs differ by no more than 15 dynes/cm, providing enhanced structural stability and permeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymer membranes are used to achieve high particulate efficiency and stability, then filtration efficiency is improved, but permeability and porosity deteriorate due to restricted pore network
Solution Approach 1:
The patent employs a porous fibrous mat structure with interconnected void spaces that allow fluid flow while trapping particles. The porous structure is created through random fiber arrangement and bonding, providing both high particulate efficiency and maintained permeability, resolving the contradiction between filtration efficiency and fluid flow capability
Solution Approach 2:
The patent uses composite fibrous materials combining different fiber types, sizes, and bonding characteristics to achieve optimal balance. The composite structure includes fine fibers for particle capture and coarser fibers for structural support, maintaining both high efficiency and good permeability simultaneously
2Reliability
If small diameter fibers are used to achieve high particulate efficiency, then filtration efficiency is improved, but structural integrity deteriorates under high pressure and temperature conditions
Solution Approach 1:
The patent applies different fiber characteristics to different regions and functions within the filter media. Fine fibers (0.1-10 microns) are distributed throughout for particle capture, while the overall mat structure provides mechanical strength. This local differentiation allows small fibers to provide efficiency without compromising overall structural integrity under pressure and temperature
Solution Approach 2:
The patent uses a flexible fibrous mat structure that can deform elastically under pressure rather than collapsing. The random fiber arrangement and bonding create a resilient network that maintains structural integrity under high pressure and temperature conditions while preserving filtration efficiency
3Productivity
If high porosity is used to maintain permeability, then fluid flow is improved, but structural stability deteriorates under various conditions
Solution Approach 1:
The patent creates a three-dimensional random fiber network with curved and interconnected pathways that provide both high porosity for fluid flow and structural stability. The curved fiber arrangements and multiple bonding points distribute mechanical stresses, maintaining structural stability even with high porosity (50-90%) that enables good permeability
4Stress or pressure
If nanofibrous media are exposed to high pressure greater than 30 psi, then compression occurs, but structural integrity is irreversibly compromised resulting in decreased particulate efficiency
Solution Approach 1:
The patent designs the fibrous mat with inherent compressibility and rebound characteristics that cushion against high pressure impacts. The flexible fiber network can temporarily compress under pressure greater than 30 psi but rebounds to its original configuration, preventing irreversible structural damage and maintaining particulate efficiency after pressure exposure
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 filter media maintains high particulate efficiency and permeability while ensuring structural integrity under diverse conditions, meeting standards like ASTM F838-05 and exhibiting stable water permeability and dirt holding capacity.
Implementation Method 1
The first and second fiber webs are bonded to one another in any suitable manner, such as by adhesive bonding, thermal bonding, ultrasonic bonding, or the like.
Implementation Method 2
The fiber web provides a porous structure that permits fluid (e.g., gas, liquid) to flow through the media.
Data Source
AI summary
Filter media comprising nanofibers and related components, systems, and methods associated therewith are provided. In some embodiments, a filter media may comprise a first fiber web and a second fiber web designed to impart beneficial properties to the filter media. For instance, in some embodiments, the first fiber web may provide high particulate efficiency and the second fiber web may provide suitable capacity. In some embodiments, the first and second fiber webs may have certain properties (e.g., water contact angle, surface energy) that are similar or substantially the same. The similarities between the first and second fiber webs may serve to enhance the structural stability of the filter media under various conditions (e.g., high temperature, high pressure, steam sterilization) and/or permeability to certain fluids (e.g., water). Filter media, as described herein, may be particularly well-suited for applications that involve liquid filtration.