Sandwiched Nanofiber Filter Medium for Abrasion Protection

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Solution Overview

Problem

Existing filter media with nanofiber layers suffer from mechanical damage during processing and handling due to the use of hot-melt adhesive fibers in the support layer, which are not effective in protecting the nanofibers from abrasion, especially under high volume flow, differential pressure, and viscosity conditions.

Innovation Solution

A filter medium design where the nanofiber layer is sandwiched between a substrate layer and a layer of adhesive or hot-melt adhesive fibers, with the adhesive fibers applied on the side opposite the substrate, providing a protective frame that prevents mechanical damage and ensures a strong adhesive connection between the layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If hot-melt adhesive fibers are used in the support layer to connect filter layers, then the connection strength between layers is improved, but the nanofiber layer becomes vulnerable to mechanical damage during processing and handling

Engineering Contradiction:

Improveconnection strengthVSAvoidmechanical integrity of nanofiber layer

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

Instead of placing the nanofiber layer directly on the substrate layer with adhesive fibers underneath, the invention inverts the arrangement by positioning the adhesive fibers on top of the nanofiber layer. This inversion allows the adhesive fibers to protect the nanofibers from mechanical damage while maintaining connection strength, resolving the contradiction between connection strength and mechanical integrity.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The adhesive fibers serve as an intermediary protective layer between the nanofiber layer and external mechanical stresses. By positioning the adhesive fibers on the outer surface, they act as a mediator that absorbs mechanical stresses and protects the delicate nanofibers from direct contact with damaging forces during processing and handling.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Manufacturing precision

If the nanofiber layer is positioned as the outermost layer for fine filtration, then filtration performance is improved, but the nanofibers suffer from abrasion and mechanical damage during processing and use

Engineering Contradiction:

Improvefiltration performanceVSAvoidmechanical damage to nanofibers

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The invention inverts the conventional arrangement by placing the adhesive fibers on the outer surface instead of the nanofibers. This allows the nanofiber layer to maintain its filtration function while being protected from mechanical damage by the outer adhesive fiber layer, resolving the contradiction between filtration performance and mechanical protection.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The adhesive fiber layer provides beforehand cushioning protection for the nanofiber layer against mechanical stresses and abrasion during processing, handling, and use. This protective layer is positioned in advance to prevent direct mechanical contact with the delicate nanofibers, ensuring their integrity is maintained throughout the service life of the filter element.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If adhesive fibers are applied only in the substrate layer, then connection between layers is achieved, but the nanofiber surface lacks protection from abrasion during handling and processing

Engineering Contradiction:

Improvelayer connectionVSAvoidhandling protection

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The adhesive fibers are given multiple functions: they provide layer connection when positioned in the substrate layer, and they provide surface protection when positioned on the outer surface. By applying adhesive fibers on top of the nanofiber layer, the invention achieves both connection strength and handling protection simultaneously, resolving the contradiction between connection strength and ease of manufacture.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effectively protects the nanofiber layer from mechanical damage and enhances its filtration performance by maintaining the structural integrity of the nanofiber layer during processing and use, even under challenging conditions, while ensuring a robust connection with the substrate layer.

Implementation Method 1

hot-melt adhesive fibers, wherein the nanofiber layer is located, in the sequence of layers, between the substrate layer and the adhesive fibers and/or hot-melt adhesive fibers

Methodology Applied

Scientific EffectHot-melt adhesive: Melting

Implementation Method 2

adhesive fibers, thus fibers with which adhesive connections can be produced due to their dissolving properties or melting properties

Methodology Applied

Scientific EffectDissolving: Solvation

Implementation Method 3

wherein they can be chemically or physically curing and/or the already mentioned hot-melt adhesive fibers

Methodology Applied

Scientific EffectCuring:

Data Source

PatentUS11266935B2Filter medium, method for producing same, and use of the filter medium in a filter element

Publication Date: 2022.03.08 MANN HUMMEL GMBH

AI summary

A filter medium has a substrate layer and a nanofiber layer arranged on the substrate layer. Adhesive fibers are laid onto the nanofiber layer and connect the nanofiber layer with the substrate layer. The nanofiber layer is located between the substrate layer and the adhesive fibers.