CPAP Mask Exhaust Diffuser With Non-Linear Flow Path

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Solution Overview

Problem

Conventional CPAP masks suffer from discomfort due to exhaust ports directing air jets towards the user's bedpartner, producing disruptive noise and becoming waterlogged, rendering them inoperable.

Innovation Solution

An exhaust diffuser arrangement with a diffuser housing, cavity, and coaxially aligned inlet and outlet, featuring protrusions or ribs to create a non-linear pathway for gas exhaust, and a diffuser element made of absorbent material to diffuse and absorb airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a diffuser element is mounted on the outside of the mask over the exhaust port, then noise diffusion and jet dispersion are improved, but the device becomes rigid and bulky, negatively affecting mask comfort

Engineering Contradiction:

Improvenoise and jet discomfortVSAvoidmask structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The diffuser element is nested within the mask housing structure itself, rather than being mounted externally. The housing incorporates internal diffuser surfaces and pathways that guide exhaust gas through a diffused path, eliminating the need for external attachments while maintaining noise reduction and jet dispersion functions.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The mask housing is designed with flexible materials and thin-walled structures that maintain diffuser functionality while conforming to the patient's face. The housing itself acts as the diffuser structure, using its inherent flexibility and form factor to provide effective gas diffusion without adding rigidity or bulk.

Inventive Principle:

Principle #30Flexible shells and thin films

2Object-affected harmful factors

If a traditional diffuser element is used to diffuse exhaust gas, then noise is muffled, but the element becomes waterlogged from moisture, becoming an obstruction that prevents gas passage

Engineering Contradiction:

ImprovenoiseVSAvoidgas passage functionality

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The diffuser function is extracted from a separate element and integrated into the housing structure itself. The housing walls and internal surfaces serve as the diffuser, eliminating the waterlogging problem that affects separate diffuser elements while maintaining effective noise muffling and gas diffusion capabilities.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The housing is constructed from flexible materials that resist waterlogging while maintaining structural integrity. These flexible walls allow gas to pass through while preventing moisture accumulation that would otherwise obstruct the diffuser element, ensuring continuous functionality.

Inventive Principle:

Principle #30Flexible shells and thin films

3Productivity

If exhaust ports are positioned at the front of the faceplate, then exhaust function is achieved, but air jets are directed toward the bedpartner causing discomfort and irritation

Engineering Contradiction:

Improveexhaust functionVSAvoidjet discomfort to bedpartner

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The exhaust pathway is designed with curved surfaces and rounded contours that redirect the exhaust jet in an arc away from the bedpartner. The curved housing walls guide the gas flow in a circular or spiral pattern, dispersing it laterally rather than directing it linearly toward the bedpartner, thereby eliminating discomfort while maintaining effective exhaust function.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 waterlogging, and maintains functionality by providing a non-linear exhaust path that avoids direct airflow, enhancing user comfort and mask operation.

Implementation Method 1

a diffuser element made of absorbent material to diffuse and absorb airflow

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Implementation Method 2

protrusions or ribs to create a non-linear pathway for gas exhaust, and a diffuser element made of absorbent material to diffuse and absorb airflow

Methodology Applied

Scientific EffectFlow path extension:

Data Source

PatentEP4536330B1Exhaust diffuser arrangement and CPAP mask including same

Publication Date: 2026.01.28 KONINKLIJKE PHILIPS NV

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AI summary

An exhaust diffuser arrangement includes: a housing; a cavity defined within the housing, the cavity being sized and configured to house a diffuser element therein; an inlet defined in the housing, the inlet structured to communicate gases from a main cavity to the diffuser cavity; and an outlet defined in the housing, the outlet structured to communicate gases from the diffuser cavity to an exterior environment. The inlet and the outlet are coaxially aligned.