Breathing Circuit Membrane Design for Condensation and Noise Control

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Solution Overview

Problem

Existing breathing gas conduits in respiratory apparatus face issues with condensation buildup due to high humidity, leading to durability concerns and unwanted noise, especially when moved or bent, and are difficult to make patient-friendly.

Innovation Solution

A breathing circuit component with a breathable membrane that allows vapor passage while preventing liquid water and gas flow, reinforced by a helical bead or rib structure, providing enhanced durability and reduced noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a thin breathable membrane is used to reduce condensation, then condensation control is improved, but durability and resistance to damage deteriorate

Engineering Contradiction:
Improvecondensation buildupVSAvoiddurability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent employs a thin breathable membrane (35-45 micrometers) as a flexible shell that allows water vapor transmission while blocking liquid water. This thin film structure effectively prevents condensation buildup by enabling vapor to escape through the membrane, while the membrane's material properties maintain structural integrity and durability for reliable long-term use.

Inventive Principle:
Principle #30Flexible shells and thin films

2Object-affected harmful factors

If a thin breathable membrane is used to reduce condensation, then condensation control is improved, but noise during movement deteriorates

Engineering Contradiction:
Improvecondensation buildupVSAvoidcrinkling noise
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent employs a thin breathable membrane (35-45 micrometers) as a flexible shell that allows water vapor transmission while blocking liquid water. This thin film structure effectively prevents condensation buildup by enabling vapor to escape through the membrane, while the membrane's material properties maintain structural integrity and durability for reliable long-term use.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent specifies a precise thickness range of 35-45 micrometers for the breathable membrane. This parameter optimization balances multiple properties: thin enough to allow effective vapor transmission for condensation control, but thick enough to reduce flexibility-induced crinkling noise during movement, and sufficient to maintain durability against damage.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If membrane thickness is increased to improve durability, then durability is improved, but vapor permeability deteriorates

Engineering Contradiction:
ImprovedurabilityVSAvoidwater vapor passage
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent specifies a precise thickness range of 35-45 micrometers for the breathable membrane. This parameter optimization balances multiple properties: thin enough to allow effective vapor transmission for condensation control, but thick enough to reduce flexibility-induced crinkling noise during movement, and sufficient to maintain durability against damage.

Inventive Principle:
Principle #35Parameter changes

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 reduces condensation buildup and noise, enhances durability, and improves patient acceptance by ensuring comfortable and reliable use.

Implementation Method 1

a breathable material that allows the passage of water vapour from the gases passageway, without substantially allowing the passage of liquid water or respiratory gases

Methodology Applied
Scientific EffectVapor permeability: Permeation

Implementation Method 2

Buildup of condensation on the inside wall of the breathing gas conduit is a frequent result of this high humidity

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP4223338B1Breathing circuit components for respiratory apparatus
Publication Date: 2025.08.27 FISHER & PAYKEL HEALTHCARE LTD
  • EP4223338B1 patent drawingFigure 1
  • EP4223338B1 patent drawingFigure 2
  • EP4223338B1 patent drawingFigure 3~4

AI summary

In one embodiment, a breathing circuit component is provided and comprises: an inlet; an outlet; and an enclosing wall defining a gases passageway between the inlet and the outlet, at least a region of the wall comprising a membrane that allows the passage of water vapour without substantially allowing the passage of liquid water or respiratory gases, wherein, said membrane has a thickness of about 35 to 45 micrometers.