Air Filter Composite Mechanical Bonding

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Solution Overview

Problem

Existing multilayer composites for air filters, used in filter bags, face issues of brittleness, complex manufacturing, and increased permeability due to penetration points, which affect stability and dust separation efficiency.

Innovation Solution

A multilayer composite with an upstream spunbonded nonwoven ply and a supporting ply, where continuous filaments are twisted or interwoven using water jets, providing a firm bond and fine porosity, allowing for effective dust separation without clogging the supporting ply.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If thermal bonding is used to connect the upstream ply to the supporting ply, then the multilayer composite gains sufficient stability against pressure pulses, but the composite becomes brittle and difficult to move, and manufacturing becomes complicated

Engineering Contradiction:

Improvestability against pressure pulsesVSAvoidmanufacturing complexity

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent replaces thermal bonding (thermal field) with mechanical interlocking through needling (mechanical field). The upstream ply is needled through the supporting ply, creating physical anchoring points that provide stability against pressure pulses without the brittleness and manufacturing complexity of thermal bonding processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the bonding mechanism parameter from thermal to mechanical. By using needling instead of thermal bonding, the connection method is fundamentally altered to achieve the required stability while avoiding the negative effects of thermal processes on material properties and manufacturing complexity.

Inventive Principle:

Principle #35Parameter changes

2Stability of the object's composition

If mechanical needling is used to connect staple fiber nonwovens to the supporting layer, then the multilayer composite achieves stable connection, but penetration points increase permeability to dust particles

Engineering Contradiction:

Improveconnection stabilityVSAvoidpermeability to dust particles

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by using a two-layer structure where the upstream ply has different properties from the supporting ply. The upstream ply is designed with finer fibers and lower permeability for dust separation, while the supporting ply provides mechanical stability. This local differentiation allows each layer to optimize its function without compromising the other.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining a upstream ply made from fine fibers with a supporting ply made from coarser fibers. This composite structure allows the fine upstream ply to provide dust separation while the coarser supporting ply maintains mechanical stability and reduces overall permeability to dust particles.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If staple fiber nonwovens are used in the upstream ply, then the multilayer composite can be manufactured with mechanical needling, but only relatively coarse fibers with fineness allowing carding can be used

Engineering Contradiction:

ImprovemanufacturabilityVSAvoidfiber fineness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical carding process with a needling process. Instead of requiring fibers to be carded (which limits fiber fineness), the needling process mechanically interlocks fibers of various finenesses, enabling the use of finer fibers in the upstream ply while maintaining manufacturability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fiber processing parameter from carding to needling. This parameter change removes the constraint on fiber fineness that existed with carding, allowing the use of finer fibers in the upstream ply while maintaining the ability to manufacture the composite multilayer structure.

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 solution achieves stable and cost-effective production of filter media with enhanced dust separation performance and reduced material usage, maintaining filter efficiency and mechanical stability under pressure pulses.

Implementation Method 1

the continuous filaments are introduced into the supporting ply by means of water jets

Methodology Applied

Scientific EffectHydraulic force: Hydraulic Press

Data Source

PatentUS9180394B2Multi-layer composite for use in an air filter

Publication Date: 2015.11.10 CARL FREUDENBERG KG

AI summary

The invention relates to a multi-layer composite for use in an air filter, comprising at least one upstream ply and a support ply that is connected to the upstream ply. The upstream ply is made of a non-woven fabric and has a finer porosity than the support ply. The aim of the invention is to form and further develop a multi-layer composite for use in an air filter, in particular in a filter bag in such a manner that the upstream ply can be connected in a stable and economical manner to the support ply. The invention is characterised in that the upstream ply is embodied as a spun bonded non-woven, the continuous filaments of which are at least partially twisted or interwoven with the support ply.