Exponential Pore Size Gradient Filter Media

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Solution Overview

Problem

Current filter media technologies do not effectively optimize pore size gradients to enhance filtration performance characteristics such as dust holding capacity and efficiency across the thickness of the media.

Innovation Solution

A filter media with a gradient in mean pore size represented by an exponential function across its thickness, determined using a least squares linear regression model, which provides a strong goodness of fit and enhances filtration properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a uniform pore size structure is used in filter media, then the manufacturing process is simple, but the filtration performance (dust holding capacity and efficiency) is not optimized

Engineering Contradiction:
Improvefiltration performanceVSAvoidpore size gradient structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating a pore size gradient where different regions of the filter media have different pore sizes. The upstream portion has larger pores for higher flow capacity, while the downstream portion has smaller pores for higher filtration efficiency, allowing each region to perform its specific function optimally

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the pore size parameter continuously across the thickness of the filter media using an exponential gradient function. This parameter change optimizes the balance between pressure drop and filtration efficiency by transitioning from larger pores at the inlet to smaller pores at the outlet

Inventive Principle:
Principle #35Parameter changes

2Reliability

If multiple layers with different pore sizes are stacked, then filtration efficiency can be improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvefiltration efficiencyVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the filter media into an upstream portion and a downstream portion with distinct pore size characteristics. This segmentation allows each portion to be optimized for its specific function (flow capacity vs. filtration efficiency) while maintaining a relatively simple single-layer structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of stacking multiple layers in the thickness direction, the patent creates a pore size gradient within the thickness direction itself. This dimensional approach achieves multi-layer-like performance through a continuous or discrete gradient in pore size across the media thickness

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Duration of action of moving object

If the pore size gradient is not optimized, then the manufacturing process is simpler, but the dust holding capacity and filter lifetime are reduced

Engineering Contradiction:
Improvefilter lifetimeVSAvoidpore size gradient control
Core Design Contradiction:
Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

The patent establishes a predetermined pore size gradient profile (exponential function with specific parameters) during the manufacturing process. This preliminary establishment of the optimal gradient ensures that the filter media achieves maximum dust holding capacity and extended lifetime from the outset, rather than requiring post-manufacturing adjustments

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3039177B1Filter media having an optimized gradient
Publication Date: 2021.10.06 HOLLINGSWORTH & VOSE COMPANY
  • EP3039177B1 patent drawingFigure 1A
  • EP3039177B1 patent drawingFigure 1B
  • EP3039177B1 patent drawingFigure 2A

AI summary

Filter media having a gradient in a property and methods associated with such media are provided. In some embodiments, a filter media may have a gradient in mean pore size. The gradient in mean pore size may be across at least a portion of the thickness of the filter media. In some embodiments, the gradient can be represented by an exponential function. The exponential gradient in mean pore size may impart desirable properties to the filter media including enhanced filtration properties (e.g., relatively high dust holding capacity and efficiency), amongst other benefits. The filter media may be particularly well-suited for applications that involve filtering liquids (e.g., hydraulics, fuel, lube, water), though the media may also be used in other applications.