PVDF Nanofiber Filter with Segmented Layers for Low Pressure Drop
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Solution Overview
Problem
Conventional filters face challenges with cake formation and pressure drop, leading to reduced filtration efficiency and aerosol storage capacity, especially when dealing with submicron aerosols like COVID-19, which limits their usage time and effectiveness in disinfection.
Innovation Solution
A high filtration filter with electrostatically-charged polyvinylidene fluoride (PVDF) nanofiber mats, alternating module layers, and separators is designed to minimize cake formation, enhance aerosol storage capacity, and maintain low pressure drop by optimizing fiber basis weight and packing density, ensuring uniform aerosol trapping and disinfection across the filter thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional filters are used to capture submicron aerosols, then filtration efficiency is achieved, but cake formation occurs on the upstream side leading to increased pressure drop and reduced usage time
Solution Approach 1:
The filter is divided into multiple module layers (at least two) with different fiber basis weights arranged in sequence from upstream to downstream. The upstream module layer has a first fiber basis weight optimized for initial aerosol capture, while downstream module layers have a second fiber basis weight that prevents cake formation. This segmentation allows the filter to maintain low pressure drop throughout extended usage while sustaining high filtration efficiency.
Solution Approach 2:
Different regions of the filter (upstream vs downstream module layers) are assigned different fiber basis weights to perform different functions. The upstream layer with higher fiber basis weight captures aerosols effectively, while downstream layers with optimized fiber basis weight prevent cake formation and maintain low pressure drop. This local quality differentiation resolves the contradiction between filtration efficiency and usage duration.
2Reliability
If fiber packing density is increased to improve filtration efficiency, then aerosol capture improves, but pressure drop across the filter increases
Solution Approach 1:
The fiber basis weight parameter is varied across different module layers to optimize both filtration efficiency and pressure drop. By changing this parameter from upstream to downstream, the filter achieves high aerosol capture in the upstream layer while maintaining low pressure drop in downstream layers, resolving the contradiction between these two performance metrics.
3Ease of manufacture
If single-layer filter design is used, then manufacturing is simple, but aerosol storage capacity is limited and cake formation occurs
Solution Approach 1:
The filter is segmented into multiple module layers with different fiber basis weights, which increases aerosol storage capacity and prevents cake formation. While this multi-layer approach is more complex than a single layer, each module can be manufactured as a standardized unit and then assembled, maintaining reasonable manufacturing simplicity while achieving superior performance.
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 significantly reduces cake formation, extends usage time, maintains low pressure drop, and achieves high filtration efficiency, ensuring effective disinfection of aerosols by uniformly distributing aerosol trapping and utilizing the full filter thickness for aerosol storage and capture.
Implementation Method 1
Each individual module layer is an electrostatically-charged polyvinylidene fluoride (PVDF) nanofiber mat
Implementation Method 2
the capturing mechanism is by means of diffusion. When the small aerosol making random motion departs from the streamline of the flow due to its small size
Implementation Method 3
The filter includes a plurality of module layers and a plurality of separators. An individual module layer is an electrostatically-charged polyvinylidene fluoride (PVDF) nanofiber mat with charged nanofibers configured to capture aerosols
Data Source
AI summary
A high filtration filter for filtering aerosols with low pressure drop across the filter and reduced cake formation when the aerosols penetrate through from an upstream side to a downstream side is disclosed. The filter (100) includes a plurality of module layers (110) and a plurality of separators (120). An individual module layer is an electrostatically-charged polyvinylidene fluoride (PVDF) nanofiber mat. The electrostatically-charged PVDF nanofiber mat with charged nanofibers is configured to better capture aerosols. The plurality of module layers and the plurality of separators are alternatingly stacked and connected to one another. Each of the individual module layers has an appropriate fiber basis weight, thereby the aerosols are captured by the charged nanofibers and distributed uniformly across an entire width of the filter from the upstream side (41) to the downstream side (42). The fiber basis weight of nanofibers is selected to minimize the formation of skin leading to formation of a cake layer on the upstream side of the filter module. The filter also carries antimicrobials to disinfect bacteria, viruses, and harmful microbials carried by the trapped aerosols in the filter.