Pleated Fluid Filter Element With Uncoupled Layers for Low Pressure Drop

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Solution Overview

Problem

Existing fluid filter elements face challenges in achieving high dust holding capacity and maintaining low clean pressure drop while maintaining structural integrity and efficiency, particularly in filtering hydraulic fluids, due to conventional understanding of pore size interactions and pleat density limitations.

Innovation Solution

A pleated filter element design with uncoupled filter media layers and a support layer system, featuring a downstream media layer with smaller mean flow pore size than the upstream layer, and wire mesh layers, configured to achieve a pleat packing density of greater than 125%, with linear pleat densities of at least 8 pleats per inch, enhancing filtration performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If pleat packing density is increased to improve filtration capacity, then dust holding capacity is improved, but clean pressure drop increases and structural integrity deteriorates

Engineering Contradiction:

Improvedust holding capacityVSAvoidclean pressure drop

Core Design Contradiction:

Quantity of substanceVSStress or pressure

Solution Approach 1:

The filter media is divided into multiple uncoupled layers (first media layer, second media layer, support layer system) that can be independently pleated and compressed. This segmentation allows each layer to contribute to dust holding capacity while the cumulative effect maintains lower pressure drop than a single dense layer would produce.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple filter media layers are nested together in a stacked configuration, with each layer containing within the same pleat structure. The nested arrangement of uncoupled layers enables high pleat packing density (>125%) while maintaining structural integrity and acceptable pressure drop characteristics.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Quantity of substance

If pleat packing density is increased to improve filtration capacity, then dust holding capacity is improved, but structural integrity deteriorates

Engineering Contradiction:

Improvedust holding capacityVSAvoidstructural integrity

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The filter assembly uses composite construction with multiple different media layers (first media layer, second media layer, support layer system) that are uncoupled but pleated together. This composite structure achieves high pleat packing density while maintaining structural integrity through the combined properties of different materials.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

Different regions of the filter assembly have different media properties optimized for specific functions. The support layer system provides structural reinforcement in areas requiring strength, while other layers are optimized for dust capture, allowing high pleat packing density without compromising overall structural integrity.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If downstream media layer has smaller pore size to improve filtration efficiency, then particle capture is improved, but pressure drop increases

Engineering Contradiction:

Improvefiltration efficiencyVSAvoidpressure drop

Core Design Contradiction:

Measurement precisionVSStress or pressure

Solution Approach 1:

The filtration function is segmented across multiple layers with different pore sizes. The first media layer and second media layer have different mean flow pore sizes, allowing each layer to perform specific filtration functions. This segmentation enables high filtration efficiency through the downstream smaller-pore layer while the upstream larger-pore layers prevent premature clogging and maintain lower overall pressure drop.

Inventive Principle:

Principle #1Segmentation

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 design achieves improved dust holding capacity, reduced clean pressure drop, and maintains filtration integrity with increased pleat density, defying conventional expectations of performance degradation with higher pleat packing.

Implementation Method 1

a first layer of filter media and a second layer of filter media that is adjacent to the first media layer... The second media layer has a mean flow pore size equal to or smaller than the first media layer

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Data Source

PatentUS20250352927A1Pleated fluid filter element and methods

Publication Date: 2025.11.20 DONALDSON CO INC

AI summary

A filter element has an upstream and downstream side. A filter media assembly of the filter element has an upstream side and a downstream side and has a first filter media layer and a second filter media layer that is adjacent to the first media layer. A substantial portion of the first layer and second layer are uncoupled, and at least one of the first media layer and second media layer comprises binder fiber. The second media layer has a mean flow pore size equal to or smaller than the first media layer. A support layer system is adjacent to the downstream side of the filter media assembly, and a first wire mesh layer is adjacent to the support layer system. At least the first media layer, second media layer, support layer system, and first wire mesh cooperatively define pleats at a pleat packing density of greater than 125%.