Patient Interface Seal Structure to Prevent Blowout Under Pressure

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Solution Overview

Problem

Existing respiratory treatment systems, such as CPAP therapy, suffer from discomfort, poor fit, and reduced patient compliance due to inadequate seal-forming portions and stabilizing structures in patient interfaces, leading to leaks and increased noise, which affect the efficacy and comfort of respiratory therapies.

Innovation Solution

A patient interface with a sealing structure comprising a textile portion and a support structure, featuring a tie that resists deformation and maintains a seal against the face, along with a positioning and stabilizing structure to ensure effective delivery of therapeutic air pressure without leaks, and a gas washout vent to minimize rebreathing of CO2.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a seal-forming portion is used to create a seal against the patient's face, then the seal effectiveness is improved, but the seal-forming portion may deform or blow out due to internal pressurization

Engineering Contradiction:
Improveseal effectivenessVSAvoidseal-forming portion deformation
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent employs a flexible membrane as the seal-forming portion that can deform to conform to the patient's face while maintaining sealing effectiveness. The membrane is supported by a structure that prevents excessive deformation or blowout due to internal pressurization, combining flexibility with structural support.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing structure combines a flexible membrane material with a support structure material to create a composite assembly. This allows the seal-forming portion to have both the compliance needed for effective sealing and the structural integrity to resist deformation under pressure.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If a rigid support structure is used to prevent seal deformation, then the seal stability is improved, but the comfort and fit against the patient's face deteriorates

Engineering Contradiction:
Improveseal-forming portion stabilityVSAvoidpatient comfort and fit
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent uses a flexible membrane instead of a rigid structure for the seal-forming portion. This flexible membrane can adapt to the contours of the patient's face, providing both stability and comfort. The membrane maintains its shape under pressure while conforming to facial features.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing structure has different properties in different regions: the seal-forming portion is flexible and compliant for comfort, while the support structure provides rigidity where needed for stability. This local differentiation of material properties resolves the contradiction between comfort and stability.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the seal-forming portion is made more compliant for comfort, then the patient compliance is improved, but the seal may deform under therapeutic pressure

Engineering Contradiction:
Improvepatient complianceVSAvoidseal integrity under pressure
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent creates a composite sealing assembly where a compliant membrane material provides patient comfort and compliance, while an integrated support structure maintains seal integrity under therapeutic pressure. The combination allows both comfort and reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The flexible membrane provides comfort and compliance for patient wear, while the support structure embedded within or behind the membrane prevents excessive deformation under pressure, maintaining seal integrity throughout the respiratory cycle.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If stabilizing structures are added to prevent seal deformation, then the seal reliability is improved, but the device complexity increases

Engineering Contradiction:
Improveseal reliabilityVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the support structure with the membrane to form a unified sealing assembly. Rather than adding separate stabilizing components, the support function is merged into the seal-forming structure itself, reducing overall device complexity while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The support structure is designed as a thin, flexible component that works in conjunction with the membrane, avoiding bulky or complex stabilization mechanisms. This integrated approach maintains seal reliability without significantly increasing device complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP4647098A1Patient interface with blowout prevention for seal-forming portion
Publication Date: 2025.11.12 RESMED PTY LTD
  • EP4647098A1 patent drawingFigure 1A
  • EP4647098A1 patent drawingFigure 1B
  • EP4647098A1 patent drawingFigure 1C

AI summary

The present invention discloses an assembly for a patient interface comprising: a plenum chamber pressurisable to a therapeutic pressure of at least 6cmH2O above ambient air pressure, said plenum chamber including a plenum chamber inlet port, said plenum chamber inlet port being sized and structured to receive a flow of air at the therapeutic pressure for breathing by a patient; and a sealing structure comprising a support structure and a textile portion joined to the support structure, the sealing structure being constructed and arranged to have a shape to form a seal with a region of the patient's face surrounding an entrance to the patient's airways such that the flow of air at said therapeutic pressure is delivered to at least an entrance to the patient's nares, said seal being formed to prevent air exiting from the plenum chamber between the sealing structure and said region of the patient's face, the sealing structure structured and arranged to maintain said therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use; wherein the sealing structure comprises a sealing surface that forms the seal against the patient's face in use, wherein the textile portion comprises a connecting portion that extends between a first interior surface region of the sealing structure that is opposite the sealing surface and a second interior surface region of the assembly such that the connecting portion resists deformation of the sealing structure to prevent blowout.