Filter Media With Corrugated Downstream Layer

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Solution Overview

Problem

The life of filter media is limited by the accumulation of dust and particulates, which increases resistance to fluid flow, leading to a high differential pressure and reduced airflow, indicating the end of its service life.

Innovation Solution

A filter media design with a corrugated downstream layer and a non-corrugated upstream layer of fibers, where the upstream layer has a mean fiber diameter of at least 10 microns and less than 10% solidity, and a mean void distance of greater than 0.11 mm between the layers, enhancing dust loading capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the filter media accumulates dust and particulates, then the filtration capacity increases, but the resistance to fluid flow increases and service life decreases

Engineering Contradiction:
Improvedust loading capacityVSAvoidservice life
Core Design Contradiction:
Quantity of substanceVSDuration of action of stationary object

Solution Approach 1:

The filter media is divided into multiple layers with distinct functions: a first layer for initial particle capture and a second layer for deeper filtration. This segmentation allows dust to be distributed across different layers, preventing rapid saturation of a single layer and extending overall service life while maintaining high dust loading capacity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a depth dimension by using a multi-layer structure with corrugated geometry. The corrugations create valleys that provide additional three-dimensional space for dust accumulation, effectively increasing the dust loading capacity without proportionally increasing the resistance to fluid flow through the media.

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

2Ease of manufacture

If the filter media structure is simplified, then manufacturing cost decreases, but filtration efficiency may be compromised

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidfiltration efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent specifies particular parameter ranges for the filter layers, including fiber diameter (10-50 microns for first layer, 1-10 microns for second layer), basis weight (5-50 gsm for first layer, 20-100 gsm for second layer), and open area (50-90% for first layer, 30-70% for second layer). These optimized parameters ensure high filtration efficiency while maintaining manufacturability through standard production processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The filter media uses composite construction with two different layers having distinct properties. The first layer uses coarser fibers with higher open area for pre-filtration, while the second layer uses finer fibers with lower open area for fine particle capture. This composite approach achieves high filtration efficiency through material differentiation rather than complex structural design, keeping manufacturing straightforward.

Inventive Principle:
Principle #40Composite materials

3Quantity of substance

If the differential pressure across the filter media increases, then the dust capture capacity improves, but the airflow rate decreases

Engineering Contradiction:
Improvedust capture capacityVSAvoidairflow rate
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The filter media applies local quality differentiation through its multi-layer structure with varying properties. The first layer has higher open area (50-90%) and coarser fibers to maintain low resistance and high airflow, while the second layer has lower open area (30-70%) and finer fibers for enhanced dust capture. This local optimization allows the system to achieve good dust capture capacity without uniformly increasing differential pressure that would restrict airflow.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The corrugated geometry of the filter media creates dynamic flow paths that adapt to dust loading conditions. As dust accumulates in the valleys, the flow dynamically adjusts through the peaks and remaining open spaces, maintaining relatively stable airflow rates even as dust capture capacity increases and differential pressure rises.

Inventive Principle:
Principle #15Dynamics

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 improved dust loading extends the useful life of the filter media by reducing resistance to fluid flow and maintaining efficient airflow.

Implementation Method 1

an upstream layer of fibers extending across the peaks of the downstream layer of filter material

Methodology Applied
Scientific EffectInterception: Absorption (physical)

Implementation Method 2

The upstream layer of fibers has a mean fiber diameter of at least 10 microns

Methodology Applied
Scientific EffectInertial impaction: Impact Force

Implementation Method 3

a downstream layer of filter material in a corrugated configuration defining peaks and valleys

Methodology Applied
Scientific EffectCorrugation: Corrugation

Data Source

PatentEP3946678B1Filter media with improved dust loading
Publication Date: 2025.12.03 DONALDSON CO INC
  • EP3946678B1 patent drawingFigure 1
  • EP3946678B1 patent drawingFigure 2
  • EP3946678B1 patent drawingFigure 3

AI summary

Embodiments disclosed herein relate to filter media having a downstream layer of filter material and an upstream layer of fibers. The downstream layer of filter material has a capture efficiency of at least 10% and the upstream layer of fibers has a mean fiber diameter of at least 10 microns and a solidity of less than 10%. A spacing structure defines a mean void distance between the upstream layer of fibers and the downstream layer of filter material.