Coreless Spiral-Wound Filter Element With Radial Porosity Control

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Solution Overview

Problem

Existing filter elements face challenges in achieving high filtration efficiency and structural integrity without a core, particularly in maintaining porosity and permeability while ensuring effective removal of particles and contaminants.

Innovation Solution

A coreless filter element is designed with spirally wound non-woven strips of selected porosity, featuring interlaying strips of higher density and lower permeability, allowing for radial fluid flow and axial filtration patterns to enhance particle removal and flow capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coreless filter element design is used, then structural integrity and filtration efficiency are improved, but maintaining porosity and permeability becomes more difficult

Engineering Contradiction:
Improvestructural integrityVSAvoidporosity control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The filter element employs varying porosity across different radial positions, with higher porosity near the inner radius and lower porosity near the outer radius. This local variation in porosity distribution allows the element to maintain structural integrity while preserving filtration efficiency, as each region contributes differently to both support and fluid passage.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The filter element is constructed as a composite structure with multiple layers having different porosity characteristics. The composite design combines materials and structures that provide both mechanical strength and controlled permeability, enabling the coreless element to achieve both structural integrity and porosity control simultaneously.

Inventive Principle:
Principle #40Composite materials

2Reliability

If higher density interlaying strips are used, then particle removal capability is improved, but fluid flow capacity decreases

Engineering Contradiction:
Improveparticle removal efficiencyVSAvoidfluid flow capacity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The interlaying strips are positioned at specific radial locations where they provide enhanced particle removal through their higher density, while the overall porosity gradient ensures that fluid flow capacity is maintained in other regions. This localized enhancement of filtration function does not compromise overall flow capacity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The filter element utilizes a radial porosity gradient, varying porosity in the radial dimension rather than uniformly across the element. This dimensional variation allows different regions to specialize in either particle removal or fluid passage, resolving the contradiction between filtration efficiency and flow capacity.

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

3Strength

If multiple overlapping layers are wound tightly, then structural support is improved, but porosity and permeability are reduced

Engineering Contradiction:
Improvestructural supportVSAvoidporosity
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The winding structure creates local variations in density and porosity, with tighter winding providing structural support in regions requiring strength, while less dense regions maintain porosity for fluid passage. This local differentiation resolves the contradiction between structural support and porosity retention.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The filter element design incorporates a dynamic porosity gradient that varies continuously through the radial thickness, allowing the structure to adapt between providing mechanical support and maintaining fluid passage pathways. This dynamic variation in porosity distribution enables both structural integrity and adequate permeability.

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 design achieves efficient filtration with increased particle removal capabilities and flow capacity, maintaining structural integrity without a core, and allows for systematic variation of porosity and density across the filter element.

Implementation Method 1

an interlaying strip being disposed as multiple overlapping layers circumferentially about the band formed by the non-woven strip or being disposed as one layer circumferentially about the band formed by the non-woven strip, wherein the interlaying strip is more dense that the non-woven strip and has a porosity less permeable than that of the non-woven strip; and a fluid flow pathway defined by the interlaying strip

Methodology Applied
Scientific EffectPermeability: Permeation

Implementation Method 2

a non-woven strip having a selected porosity and being spirally wound upon itself in multiple overlapping layers to form at least one band of a selected radial thickness

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2703114B1Filter element and method of using same
Publication Date: 2023.02.22 PARKER HANNIFIN CORP
  • EP2703114B1 patent drawingFigure 1~2
  • EP2703114B1 patent drawingFigure 3~4
  • EP2703114B1 patent drawingFigure 5

AI summary

A coreless and spirally wound non-woven filter element is provided. The filter element includes at least one band of base media having a selected porosity and an interlay having a different porosity within at least one band of base media. The presence of the interlay in the filter element can create additional surface area within the contiguous construction of a filter element for filtration. This interlay can also create the ability to change direction of flow and to increase the deposition of specifically sized contaminants.