Laminated Membrane Filter Material for Compact Stable Air Filtration

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Solution Overview

Problem

Existing filter materials for air filtration require additional installation space due to the need for separate pleating of multiple layers, leading to reduced compactness and stability, and suffer from inefficient filtration efficiency over time.

Innovation Solution

A filter material comprising a pre-filter layer, activated carbon layer, and composite layer with a membrane, bonded together through lamination, providing enhanced mechanical stability and filtration efficiency without increasing installation space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If multiple filter layers are connected by co-pleating (folding together), then the filter element can be assembled, but the mechanical stability is reduced and the filter element requires larger installation space

Engineering Contradiction:
Improveinstallation spaceVSAvoidmechanical stability
Core Design Contradiction:
Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent combines multiple filter layers (pre-filter layer, activated carbon layer, and composite layer with membrane) into a single bonded filter material through lamination. This merging eliminates the need for separate co-pleating of multiple layers, reducing installation space while maintaining structural integrity through the bonded connection.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a composite structure by bonding different filter layers together to form a unified filter material. The lamination process creates a composite material that integrates the functional properties of each layer (coarse filtration, adsorption, fine filtration) while providing mechanical stability through the bonded connection.

Inventive Principle:
Principle #40Composite materials

2Reliability

If multiple filter layers are connected by co-pleating, then the filter element can be assembled, but the filtration efficiency becomes less stable over time

Engineering Contradiction:
Improvefiltration efficiency stabilityVSAvoidmulti-layer assembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

By bonding the filter layers into a single unified filter material, the patent eliminates the relative movement and misalignment that occur with co-pleating. This ensures consistent filtration efficiency over time as the layers maintain their precise spatial relationship, reducing the complexity of multi-layer assembly.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If polymer-based membranes are used for fine filtration, then particles in micron and sub-micron range can be filtered, but additional mechanical reinforcement is required due to low inherent stability

Engineering Contradiction:
Improvefine particle filtration capabilityVSAvoidmembrane mechanical stability
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The patent creates a composite layer by bonding the polymer-based membrane to a carrier layer. The carrier layer provides the necessary mechanical reinforcement and stability, while the membrane maintains its fine filtration capabilities for particles in the micron and sub-micron range. This composite structure allows the membrane to function effectively without compromising mechanical strength.

Inventive Principle:
Principle #40Composite materials

4Stability of the object's composition

If the filter material is designed with bonded layers instead of co-pleated layers, then mechanical stability and temperature stability are improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improvetemperature stabilityVSAvoidlamination process complexity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent employs lamination processes that bond layers through controlled parameters such as heat, pressure, or adhesive application. These parameter-controlled bonding processes create strong, stable connections between layers that maintain structural integrity under temperature variations, achieving superior temperature stability despite the added manufacturing steps.

Inventive Principle:
Principle #35Parameter changes

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 bonded filter material maintains high filtration efficiency with reduced pressure drop and energy consumption, while ensuring long-lasting performance and compact design.

Implementation Method 1

an activated carbon layer (3) as the adsorption layer

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 2

the membrane can be permeable, semi-permeable, or impermeable. Thus, particles in the micron and sub-micron range can be filtered

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentEP4620555A1Filter material with membrane and filter element made of such filter material
Publication Date: 2025.09.24 CARL FREUDENBERG KG
  • EP4620555A1 patent drawingFigure 1~2
  • EP4620555A1 patent drawingFigure 3~4
  • EP4620555A1 patent drawingFigure 5

AI summary

The invention relates to a filter material (10) for air filtration in a filter element (100) and to a filter element made of such a filter material. The filter material (10) is equipped with an upstream pre-filter layer (2), an activated carbon layer (3), and a composite layer (1) comprising at least one membrane. According to the invention, the layers are bonded to one another. Thanks to the combination of pre-filter layer and composite layer with membrane in one filter material, a high dust holding capacity with a high quality factor is advantageously achieved.