Gradient Nonwoven Filter Material for Delamination Resistance

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Solution Overview

Problem

Existing filter materials face issues with mechanical stability, delamination, and inefficiencies in air permeability, filtration efficiency, and dust holding capacity, particularly when pleated, due to distinct fiber diameters and layers that create stress points.

Innovation Solution

A single-layer nonwoven filter material with a gradient of fiber densities and porosities, formed by applying a temperature gradient during manufacturing, ensuring seamless integration of fiber sections with different densities and porosities without distinct separation surfaces, using the same type of fibers throughout.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple layers of filter media with different fiber diameters are stacked and laminated to achieve gradient pore sizes, then filtration efficiency and dust holding capacity are improved, but mechanical stability deteriorates and delamination occurs during pleating

Engineering Contradiction:
Improvefiltration efficiencyVSAvoidmechanical stability
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent combines multiple filter layers into a single integrated nonwoven structure where different fiber density regions are formed within one continuous material matrix. This merging eliminates the distinct interfaces between layers that cause delamination, while still maintaining the gradient pore size structure needed for efficient filtration and dust holding capacity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates local variations in fiber density within a single nonwoven layer, forming high-density regions for efficient filtration and low-density regions for dust storage. This local quality differentiation achieves the functional benefits of multi-layer structures without the mechanical weaknesses of stacked layers.

Inventive Principle:
Principle #3Local quality

2Productivity

If coarser fibers are used on the upstream side to increase pore size and air permeability, then air flow is improved, but filtration efficiency decreases

Engineering Contradiction:
Improveair permeabilityVSAvoidfiltration efficiency
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements spatially varying fiber densities within a single nonwoven layer, creating low-density regions for high air permeability and high-density regions for efficient particle capture. This local differentiation allows both functions to coexist in one integrated structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

Instead of using multiple layers stacked in the thickness direction, the patent creates density gradients within the plane of a single layer, utilizing in-plane variations in fiber distribution to achieve both high permeability and high filtration efficiency simultaneously.

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

3Reliability

If finer fibers are used on the downstream side to reduce pore size and improve filter separation efficiency, then filtration performance is enhanced, but air permeability and dust holding capacity decrease

Engineering Contradiction:
Improvefilter separation efficiencyVSAvoidair permeability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent creates localized high-density regions within the nonwoven structure that provide efficient particle capture, while surrounding low-density regions maintain open pathways for air flow and dust storage. This local quality differentiation resolves the trade-off between filtration efficiency and air permeability.

Inventive Principle:
Principle #3Local quality

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 provides high air permeability, mechanical stability, and efficient filtration with reduced pressure drop, while preventing delamination, and enhancing dust holding capacity and filtration efficiency, particularly effective for oil mist separation.

Implementation Method 1

applying a temperature gradient during manufacturing

Methodology Applied
Scientific EffectTemperature gradient: Temperature Gradient

Implementation Method 2

applying a temperature gradient during manufacturing... ensuring seamless integration of fiber sections with different densities and porosities

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

Filter materials are used for a variety of technical tasks. Typically, they are used for separating particles from a fluid, i.e. from a liquid or a gas.

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP4574231A1Filter material and method for providing a filter material
Publication Date: 2025.06.25 JOHNSMANVILLE EUROPE GMBH
  • EP4574231A1 patent drawingFigure 1
  • EP4574231A1 patent drawingFigure 2a~2b
  • EP4574231A1 patent drawing

AI summary

A filter material (10), namely a nonwoven material, is provided, wherein the filter material comprises a first filter section (11) and a second filter section (12), the first filter section (10) facing the upstream side (20) of the filter material (10) and the second filter section (12) facing the downstream side (30), wherein the first filter section (11) is if of higher porosity than the second filter section (12), and wherein the first and the second filter section (11, 12) merge into each other along a porosity gradient (G), so that no defined separation surface exists between the sections.