Pleated Filter Stiffening Structure for Airflow

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Solution Overview

Problem

Existing respiratory protection filters are not reusable and have limited airflow rates, requiring frequent replacement and potential leakage issues, especially in high-demand scenarios like the COVID-19 pandemic.

Innovation Solution

A folded, pleated filter with an integral stiffening structure is developed, allowing for increased filter area through material pleating and convolution, and can be overmolded for enhanced sealing, incorporating a support element and optional exhaust valve for improved airflow and reusability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a conventional flat filter design is used, then the filter area is limited, but the airflow rate is insufficient

Engineering Contradiction:

Improvefilter areaVSAvoidairflow rate

Core Design Contradiction:

Area of stationary objectVSProductivity

Solution Approach 1:

The filter media is transformed from a flat two-dimensional configuration to a three-dimensional pleated structure. The pleating process folds the filter media along crease lines to create an expanded surface area that maintains structural integrity while increasing the effective filtration area by a factor of 2-3 times compared to flat designs.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The pleated filter structure is nested within a compact housing or mask body. The pleats are arranged concentrically or in a compacted configuration that allows the expanded filter area to be contained within a small volume, enabling high airflow rate while maintaining a portable and wearable form factor.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of manufacture

If a disposable filter is used, then manufacturing is simple, but frequent replacement is required

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidfilter lifespan

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The filter assembly is designed to be removable and replaceable from the mask body. The filter media can be discarded after use while the housing, stiffening structure, and sealing components are recovered and reused. This hybrid approach maintains manufacturing simplicity for the disposable filter media while extending the overall system lifespan through reuse of durable components.

Inventive Principle:

Principle #34Discarding and recovering

Solution Approach 2:

The respiratory protection device is segmented into modular components: a disposable filter media section and a reusable housing with stiffening structure. This segmentation allows the filter media to be replaced independently without discarding the entire device, thereby extending the functional lifespan of the system while maintaining ease of manufacture for the consumable component.

Inventive Principle:

Principle #1Segmentation

3Ease of manufacture

If a flexible filter structure is used, then manufacturing is easy, but the filter collapses under operational loads

Engineering Contradiction:

Improvemanufacturing easeVSAvoidstructural stability

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The filter assembly combines flexible filter media with a rigid or semi-rigid stiffening structure. The stiffening elements, which may be made of plastic, metal, or composite materials, are integrated into the housing or attached to the filter media edges to provide structural support. This composite construction maintains the flexibility and manufacturability of the filter media while preventing collapse under negative pressure during inhalation.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

A stiffening structure or support frame acts as an intermediary between the flexible filter media and the external loads. This intermediate element absorbs and distributes mechanical stresses, protecting the filter media from direct exposure to collapsing forces while allowing the filter to maintain its shape and structural integrity during operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

4Productivity

If the filter area is increased through pleating, then airflow rate improves, but the filter becomes more prone to movement and collapse

Engineering Contradiction:

Improveairflow rateVSAvoidresistance to movement

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

Different regions of the filter assembly have different structural properties. The filter media edges and mounting regions are reinforced with stiffening structures, adhesives, or mechanical fasteners to prevent movement and collapse. The central pleated regions maintain their flexible, high-surface-area configuration for optimal airflow. This localized differentiation of structural quality allows the filter to simultaneously achieve high airflow rate and resistance to movement.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12121757B2High area filter having a stiffening structure, and methods of making the same

Publication Date: 2024.10.22 NILOV MAKSIM

AI summary

A helically pleated filter which resists movement or collapse when subjected to operational loads, which in one embodiment includes a stupport element. The construction process involves creating a tube from a sheet of filter media, closing one end using a seam, a cap, or another method, and stiffening the tube closed end with a fixedly retained stiffening element. The closed and stiffened end is then rotated relative to another section of the tube, preferably held stationary over a mandrel tool. This filter can be integrated into conventional air filtering devices, such as surgical masks, half facepiece respirators, or filter cartridges.