Electrically Charged Filter with Segmented Nonwoven Layers
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Solution Overview
Problem
Conventional electrically charged filters face challenges in maintaining high initial filtering efficiency and preventing a decline in efficiency due to electrostatic charge neutralization, especially when capturing oil mist, leading to increased pressure loss and clogging.
Innovation Solution
An electrically charged filter comprising a liquid-charged nonwoven fabric layer and a tribo-electrically charged nonwoven fabric layer, where the tribo-electrically charged layer is made from polyolefin and acrylic resin fibers with a circular cross-section, and the liquid-charged layer is positioned upstream to enhance electrostatic capture and reduce pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diameter of the fibers is reduced to increase filtering efficiency, then smaller dust particles can be captured, but initial pressure loss increases and air permeability deteriorates
Solution Approach 1:
The filter is divided into multiple layers with different fiber diameters and charging methods. The upstream layer uses larger diameter fibers (5-20 μm) charged by liquid charging, while the downstream layer uses smaller diameter fibers (1-5 μm) charged by triboelectric charging. This segmentation allows each layer to perform its specific function optimally without the downsides affecting the other.
Solution Approach 2:
Different regions of the filter have different properties: the upstream layer has larger fibers with liquid-induced charge, while the downstream layer has smaller fibers with friction-induced charge. This local differentiation optimizes both pressure loss and filtering efficiency in their respective positions.
2Reliability
If an electrically charged filter is used to improve filtering efficiency, then dust capture is enhanced, but the electrostatic charge becomes neutralized over time leading to efficiency decline
Solution Approach 1:
The filter combines two different charging mechanisms in separate layers: liquid charging for the upstream layer and triboelectric charging for the downstream layer. This segmentation ensures that neither charging method alone is responsible for efficiency decline, and the triboelectrically charged layer provides sustained charge stability.
Solution Approach 2:
The filter uses a composite structure combining fibers with different charging characteristics. The upstream layer uses fibers charged by liquid application, while the downstream layer uses fibers charged by friction between different fiber materials (polyolefin and acrylic resins), creating a composite filtering system with enhanced and sustained electrostatic properties.
3Reliability
If a single-layer electrically charged filter is used, then the structure is simple, but filtering efficiency is insufficient and pressure loss increases rapidly
Solution Approach 1:
The filter is segmented into two functional layers: an upstream layer with larger diameter fibers (5-20 μm) charged by liquid application, and a downstream layer with smaller diameter fibers (1-5 μm) charged by triboelectric friction. This segmentation enables each layer to contribute differently to dust capture, achieving high filtering efficiency while managing pressure loss effectively.
Solution Approach 2:
The invention adds the dimension of layered structure to the filter design, transitioning from a single-layer to a multi-layer configuration. This dimensional change allows simultaneous optimization of different filtering mechanisms (physical interception in upstream layer, electrostatic capture in downstream layer) without excessive complexity.
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 maintains high initial filtering efficiency and minimizes efficiency decline, even when capturing oil mist, by combining the electrostatic and physical capture mechanisms effectively, thereby reducing pressure loss and clogging.
Implementation Method 1
a liquid-charged nonwoven fabric layer which is charged by application of a force via a polar liquid
Implementation Method 2
a tribo-electrically charged nonwoven fabric layer which is charged by friction between fiber components of a plurality of types
Implementation Method 3
The capture of dust in a filter made of nonwoven fabric is principally by means of Brownian diffusion, interception, inertial impaction or the like, based on a physical action
Implementation Method 4
The capture of dust in a filter made of nonwoven fabric is principally by means of Brownian diffusion, interception, inertial impaction or the like, based on a physical action
Data Source
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AI summary
Provided is an electrically charged filter which has a high initial filtering efficiency and is not liable to decline in filtering efficiency, by including a liquid-charged nonwoven fabric layer that is charged by application of force via a polar liquid, and a tribo-electrically charged nonwoven fabric layer that is charged by friction between fiber components of a plurality of types.