Flexible Filter Element With Viscoelastic Side Bands

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Solution Overview

Problem

Existing motor vehicle interior air filters face challenges in flexibility and assembly ease due to rigid reinforcement elements, requiring complex installation and higher production costs, especially when dealing with curved receptacles and varying air flow pressures.

Innovation Solution

A flexible filter element is developed using side bands made of synthetic non-woven materials or flexible plastics with an adhesive layer that has adjustable flexibility, allowing for elastic recovery and easy assembly, utilizing adhesives with specific Shore A hardness and elongation at break properties to ensure sealing and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If rigid reinforcement elements (side bands) are used to stabilize the zigzag-shaped filter medium, then the structural stability and strength of the filter element is improved, but the flexibility and ease of assembly into curved receptacles deteriorates

Engineering Contradiction:
Improvestructural stabilityVSAvoidflexibility for assembly
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The side bands are changed from rigid materials to flexible materials with specific mechanical properties (Shore A hardness 30-80, elongation at break 20-100%). This parameter change allows the side bands to maintain structural stability while gaining the flexibility needed for easy assembly into curved receptacles and for withstanding varying air flow pressures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The side bands are made as composite structures combining a flexible plastic or synthetic non-woven material base with an adhesive layer. This composite material provides both the mechanical flexibility needed for assembly and the adhesive bonding capability for sealing and stability during operation.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If flexible materials are used for side bands to enable easy assembly into curved receptacles, then the flexibility and ease of operation is improved, but the structural stability and strength deteriorates

Engineering Contradiction:
Improveflexibility for assemblyVSAvoidstructural stability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The side bands are made as composite structures combining a flexible plastic or synthetic non-woven material base with an adhesive layer. This composite material provides both the mechanical flexibility needed for assembly and the adhesive bonding capability for sealing and stability during operation.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The adhesive layer acts as an intermediary between the flexible side band material and the filter medium/housing. It transfers and distributes mechanical loads, allowing the flexible side band to provide sealing and stabilization functions despite its inherent flexibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional rigid side bands are used, then manufacturing simplicity is maintained, but assembly complexity and production costs increase due to difficulty in handling and installing flexible configurations

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidassembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The side bands are changed from rigid materials to flexible materials with specific mechanical properties (Shore A hardness 30-80, elongation at break 20-100%). This parameter change allows the side bands to maintain structural stability while gaining the flexibility needed for easy assembly into curved receptacles and for withstanding varying air flow pressures.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If the adhesive layer is made highly flexible to enable elastic recovery, then the flexibility and ease of assembly is improved, but the sealing reliability and stability deteriorates

Engineering Contradiction:
Improveflexibility for assemblyVSAvoidsealing reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The adhesive is selected with specific parameter ranges (Shore A hardness 30-80, elongation at break 20-100%) that balance flexibility and sealing reliability. The adhesive must be flexible enough to allow assembly into curved receptacles and withstand pressure variations, but also maintain sufficient bonding strength to ensure reliable sealing.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The adhesive layer provides elastic recovery feedback during operation. When compressed by air flow pressure or during assembly, the adhesive deforms and then recovers its original shape, maintaining continuous sealing contact between the side band and the filter medium or housing surfaces.

Inventive Principle:
Principle #23Feedback

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 a more flexible and stable filter element that is easier to assemble and manufacture, accommodating curved installations while maintaining effective air filtration and cost-effectiveness.

Implementation Method 1

an adhesive layer (18) made of a flexible adhesive which has been designed to have a Shore A hardness of 300% and an elongation at break of 100%

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

The flexibility of filter elements is essentially determined by the flexibility of the adhesive used. Once the sideband has sufficient flexibility independent of an HZK stretch ratio, the flexibility and compressibility of the element are determined by the type of application and the adhesive itself.

Methodology Applied
Scientific EffectFoaming: Foam

Data Source

PatentEP1894610B1Flexible filter element
Publication Date: 2010.11.03 MANN HUMMEL GMBH
  • EP1894610B1 patent drawingFigure 1
  • EP1894610B1 patent drawingFigure 2

AI summary

A flexible filter element (10) comprises a filter insert which functions as a filter medium; and side strip(s) being arranged around lateral edges of the filter insert so to as to form a seal and a partial frame(s). The side strips have an adhesive layer on the side facing the filter insert for sealing the strip to the filter insert. The adhesive layer has a Shore A hardness of less than 65 at 23[deg] C and an break elongation of greater than 300%. An independent claim is included for a filter module (20) comprising a filter housing (22) which has a round or oval cross section and the filter element(s) (10) which is inserted into the housing so as to form a seal between the filter insert and the housing.