Foldable Wave-Shaped Filter for Consistent Filtration Gaps

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Solution Overview

Problem

Existing air purifier filter devices are bulky, costly to transport, and environmentally harmful due to plastic components, and their folding designs often result in inconsistent gaps between filtering surfaces, affecting filtration efficiency and aesthetics.

Innovation Solution

A foldable filter device with a wave-shaped filter element and flexible bonding portions made of foamable hot melt adhesive, maintaining consistent gaps between filtering surfaces through resilient supporting strips, and using flexible sealing elements to ensure air is fully filtered.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the filter element is folded for storage and transportation, then the volume is reduced and transportation cost is lowered, but the gap between filtering surfaces becomes inconsistent affecting filtration efficiency

Engineering Contradiction:
Improvevolume of filter deviceVSAvoidgap consistency between filtering surfaces
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The bonding portions are made from foamable hot melt adhesive that undergoes parameter change from liquid to foam state, providing resilient supporting strips that maintain consistent gaps between filtering surfaces during folding and unfolding, resolving the contradiction between volume reduction and gap consistency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The filter element is designed to be dynamically foldable and unfoldable, with the foamable adhesive providing adaptive support that adjusts to the folding state while maintaining gap consistency, allowing the device to transition between compact and operational states

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If flexible bonding portions are added to maintain gap consistency, then filtration efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improvegap consistency between filtering surfacesVSAvoidstructure complexity of bonding portions
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The bonding and gap-maintaining functions are merged into a single foamable hot melt adhesive material that forms resilient supporting strips, simplifying the overall structure while achieving the desired gap consistency without adding separate complex components

Inventive Principle:
Principle #5Merging (Combining)

3Strength

If plastic components are used for sealing and structure, then the structural strength is improved, but the environmental impact and cost increase

Engineering Contradiction:
Improvestructural strengthVSAvoidenvironmental impact
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The sealing components undergo parameter change from traditional plastic to foamable hot melt adhesive that cures to provide sufficient sealing strength while being environmentally friendly and cost-effective, eliminating the need for plastic components

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

Reduces transportation costs and environmental impact while maintaining consistent filtration efficiency and aesthetics by ensuring stable gaps and sealing, even when folded or unfolded.

Implementation Method 1

the flexible bonding portions are made of foamable hot melt adhesive materials

Methodology Applied
Scientific EffectFoam expansion: Foam

Implementation Method 2

the supporting strips can withstand the small extent of stretching without breaking due to the resilience of the bonding portions

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4578528A1Foldable filter device and air purifier
Publication Date: 2025.07.02 VERSUNI HLDG BV
  • EP4578528A1 patent drawingFigure 1~2
  • EP4578528A1 patent drawingFigure 3~4
  • EP4578528A1 patent drawingFigure 5~6

AI summary

The present disclosure relates to a foldable filter device (100) and an air purifier. The foldable filter device (100) includes a filter element (20), the filter element (20) is constructed into a wave shape and includes a plurality of filtering surfaces (21) connected to each other in a folded manner, peaks (250) located at an outer corner of an intersection of every two adjacent filtering surfaces (21), and valleys (270) located at an inner corner of the intersection of every two adjacent filtering surfaces (21), bonding portions (260) are provided in all or part of the valleys (270) to bond every two adjacent filtering surfaces (21), a first distance (S) is reserved between each bonding portion (260) and the corresponding peak (250), and the plurality of bonding portions (260) form supporting strips (280) on the wave-shaped filter element (20) to maintain a gap between every two adjacent filtering surfaces (21).