Reversibly Bendable Air Filter for Easy Replacement and Secure Fit

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Solution Overview

Problem

Existing air filters are difficult to replace, prone to damage, and lack stability in filter housings, leading to inefficient airflow and limited compatibility with different frame geometries and sizes.

Innovation Solution

A bendable filter that can be reversibly transformed from a resting state to an insertion state, allowing easy insertion and secure fixation within a filter housing without additional manual operations, and featuring a bending stiffness that returns it to the resting state for firm holding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the filter is made rigid to provide stability with respect to airflow, then the filtering stability is improved, but the filter becomes highly specific to certain frame sizes and shapes and is amenable to physical damage

Engineering Contradiction:
Improvefilter stabilityVSAvoidcompatibility with frame geometries
Core Design Contradiction:
Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The filter is designed with reversible bendability, allowing it to dynamically change its shape between a bent insertion state and a straight resting state. This dynamic property enables the filter to adapt to different frame geometries during insertion while maintaining stability during operation through its bending stiffness that urges it back to the resting state.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The filter's physical state is changed between bent and straight configurations. By controlling the bending parameter, the filter can transition between being adaptable (bent state for insertion) and stable (straight state for operation), resolving the contradiction between adaptability and stability.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the filter frame includes large openings to allow facile replacement of used filters, then the ease of operation is improved, but the filter is not held firmly within the filter housing and has a considerable range of movement

Engineering Contradiction:
Improvefilter replacement easeVSAvoidfilter stability in housing
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The filter's reversible bendability provides a dynamic solution: during insertion through large openings, the filter is in a bent state that facilitates easy placement, while during operation, the bending stiffness urges it back to a straight state where it is firmly held, providing stability without requiring complex locking mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The filter's own bending stiffness serves as the stabilizing mechanism. The filter automatically returns to its resting state and secures itself in the housing without requiring additional manual operations or complex structural elements, achieving both ease of replacement and firm holding.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If complex locking mechanisms are used to secure the filter in the filter frame, then the filter stability is improved, but the replacement operation becomes time-consuming and the structural elements are prone to damage

Engineering Contradiction:
Improvefilter holding securityVSAvoidreplacement time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The filter uses its own bending stiffness as a self-securing mechanism. When inserted in a bent state, the filter automatically returns to its straight resting state, which engages with the housing to provide secure holding. This eliminates the need for separate locking mechanisms, reducing replacement time and eliminating parts that could fail.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The complex locking mechanisms, closure doors, and hinges are extracted from the system. The invention achieves secure filter holding through the filter's intrinsic bending stiffness and geometry alone, removing the time-consuming and damage-prone structural elements from the replacement process.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Facilitates efficient and secure filter replacement with minimal manual effort, enhances airflow efficiency, and accommodates various filter housing geometries and sizes.

Implementation Method 1

The filter is reversibly bendable from the resting state to an insertion state in which the filter is bent along a bending axis essentially parallel to the filter plane. The filter has a bending stiffness urging the filter from the insertion state back to the resting state.

Methodology Applied
Scientific EffectBending stiffness: Elasticity

Data Source

PatentEP4696394A1Bendable filter
Publication Date: 2026.02.18 ZEHNDER GROUP INTERNATIONAL AG
  • EP4696394A1 patent drawingFigure 1~2
  • EP4696394A1 patent drawingFigure 3A~3B
  • EP4696394A1 patent drawingFigure 4A~4B

AI summary

The disclosure relates to a filter (1) extending in a resting state (2) along a filter plane and comprising a front end (11), a rear end (12) and a filter element (13) extending in a longitudinal direction between the front end (11) and the rear end (12). The filter (1) is reversibly bendable from the resting state (2) to an insertion state (3) in which the filter (1) is bent along a bending axis (4) essentially parallel to the filter plane. The filter (1) has a bending stiffness urging the filter (1) from the insertion state (3) back to the resting state (2). Further disclosed is a filter assembly (6) comprising a filter (1) and a filter housing (7).