Elastic CPAP Exhaust Diffuser Housing for Noise and Moisture Control

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Solution Overview

Problem

Conventional CPAP masks suffer from discomfort due to air jets directed towards the bedpartner, white noise, and moisture-induced obstruction of diffuser elements, which affect the mask's functionality and comfort.

Innovation Solution

An exhaust diffuser arrangement with an elastically deformable diffuser housing and non-linear pathways formed by protrusions or ribs to accommodate and diffuse exhaled gases, allowing for easy insertion and removal of a diffuser element, preventing waterlogging and maintaining functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a rigid diffuser element is mounted on the outside of the mask over the exhaust port, then noise is reduced and gas flow is diffused, but the mask becomes bulky and uncomfortable to wear

Engineering Contradiction:
ImprovenoiseVSAvoidcomfort
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent employs a flexible, collapsible diffuser housing made of elastomeric material that can be compressed flat against the mask when not in use, eliminating bulkiness. During operation, the housing expands to provide adequate space for the diffuser element, thus maintaining both comfort and noise reduction functionality.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The diffuser housing is designed to be dynamically adjustable between a collapsed state (for comfort) and an expanded state (for functionality). The elastomeric material allows the housing to adapt its volume based on operational requirements, resolving the contradiction between comfort and effective diffuser operation.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If a traditional diffuser element is used, then gas flow is diffused and noise is reduced, but the diffuser element becomes waterlogged and obstructed, rendering it inoperable

Engineering Contradiction:
ImprovenoiseVSAvoidfunctionality
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The diffuser housing is segmented into multiple chambers separated by partitions, allowing exhaled gases to be distributed across multiple pathways. This segmentation prevents moisture accumulation in a single location, reducing waterlogging and maintaining long-term functionality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The diffuser element and housing utilize porous elastomeric materials that allow gas passage while resisting moisture absorption. The porous structure enables continuous gas flow without becoming clogged by moisture, maintaining reliability during extended use.

Inventive Principle:
Principle #31Porous materials

3Device complexity

If a single exhaust port is used, then the structure is simple, but jets of air are directed toward the bedpartner causing discomfort and irritation

Engineering Contradiction:
ImprovestructureVSAvoiddiscomfort
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The exhaust system is divided into multiple exhaust ports distributed across the diffuser housing, allowing the exhaled gas flow to be split into several directed streams. This segmentation disperses the air jets away from the bedpartner while maintaining structural simplicity through the use of a single integrated housing component.

Inventive Principle:
Principle #1Segmentation

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 muffles noise, prevents obstruction, and maintains gas flow by using an elastically deformable diffuser housing with non-linear pathways, enhancing user comfort and mask functionality.

Implementation Method 1

The diffuser housing is formed from an elastic material adjacent the diffuser outlet such that the diffuser housing, and thus the diffuser outlet, is elastically deformable from: a first sizing wherein the diffuser outlet is structured to prohibit the diffuser element from passing therethrough

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

non-linear pathways formed by protrusions or ribs to accommodate and diffuse exhaled gases

Methodology Applied
Scientific EffectFluid flow through non-linear pathways:

Implementation Method 3

The solution effectively muffles noise

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Data Source

PatentEP4536329B1Exhaust diffuser arrangement and CPAP mask including same
Publication Date: 2025.12.24 KONINKLIJKE PHILIPS NV
  • EP4536329B1 patent drawingFigure 1
  • EP4536329B1 patent drawingFigure 2
  • EP4536329B1 patent drawingFigure 3

AI summary

An exhaust diffuser arrangement (40) includes: - a housing (42); - a cavity (44) defined within the housing, the cavity being sized and configured to house a diffuser element (50) therein; - an inlet (46) defined in the housing, the inlet structured to communicate gases from a main cavity to the diffuser cavity; and - an outlet (48) defined in the housing, the outlet structured to communicate gases from the diffuser cavity to an exterior environment. The housing is formed from an elastic material adjacent the outlet such that the housing, and thus the outlet, is elastically deformable from: a first sizing wherein the outlet is structured to prohibit the diffuser element from passing therethrough and thus the diffuser element is captively positioned within the cavity; and a second sizing in which the outlet is structured to allow the diffuser element to readily pass through the outlet for placing the diffuser element in or from the cavity.