Respiratory Gas Humidification With Heated Vapour and Liquid Trapping

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Solution Overview

Problem

Existing respiratory therapies and devices for treating respiratory disorders suffer from discomfort, poor fit, high cost, and reduced patient compliance due to inadequate design and functionality, particularly in patient interfaces and humidification systems, leading to suboptimal treatment outcomes.

Innovation Solution

A respiratory treatment apparatus that increases the absolute humidity of air delivered to the airways by using a reservoir, heating element, and liquid trap to enhance comfort and efficacy, while maintaining a sealed gas flow path and controlling humidity levels, thereby improving patient compliance and treatment effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a humidification system is added to respiratory therapy apparatus, then patient comfort and compliance are improved, but device complexity and cost increase

Engineering Contradiction:
Improvepatient complianceVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The humidification chamber is nested within the patient interface housing, with the reservoir integrated into the same structure. The heating element is contained within the chamber, and the liquid trap is positioned at the lowest point of the integrated assembly. This nested configuration allows multiple humidification components to occupy shared space, reducing overall device complexity while maintaining patient comfort benefits.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The humidification system is merged with the patient interface housing to form an integrated assembly. The reservoir, chamber, heating element, and liquid trap are combined into a single unified structure that interfaces directly with the patient, eliminating the need for separate humidification devices and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Quantity of substance

If heating element is used to create vapour, then humidity levels are improved, but risk of overheating and boiling water increases

Engineering Contradiction:
Improvehumidity levelsVSAvoidoverheating risk
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

A temperature sensor continuously monitors the temperature of the liquid in the reservoir and provides feedback to the controller. The controller adjusts the heating element operation based on this feedback, maintaining the liquid temperature below boiling point while ensuring sufficient vaporization for optimal humidity levels, thus preventing overheating hazards.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the heating power parameter based on temperature sensor feedback to maintain optimal humidity generation without exceeding safe temperature thresholds. The controller modulates the heating element to operate in a controlled parameter range that prevents boiling while achieving desired vaporization rates.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If liquid trap is positioned at lowest point, then liquid drainage is improved, but device orientation flexibility is reduced

Engineering Contradiction:
Improveliquid drainageVSAvoiddevice orientation
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The liquid trap is segmented from the main humidification chamber and positioned in a dedicated lowest-point location within the integrated assembly. This segmentation allows the trap to function independently as a drainage reservoir, ensuring efficient liquid collection and drainage regardless of the overall device orientation during patient use.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The liquid trap is positioned in the vertical dimension at the lowest point of the humidification assembly, creating a gravity-dependent drainage path that operates effectively in various device orientations. This dimensional positioning ensures liquid always drains to the trap regardless of whether the device is held upright, tilted, or in other orientations during patient interface.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Quantity of substance

If sealed gas flow path is implemented, then humidity retention is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvehumidity retentionVSAvoidsealing precision
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

Flexible sealing elements are used at the interfaces between the reservoir, chamber, and housing components. These flexible seals accommodate minor manufacturing tolerances and assembly variations while maintaining effective sealing to prevent humidity loss, thereby reducing the stringency of manufacturing precision requirements while ensuring proper sealed gas flow path functionality.

Inventive Principle:
Principle #30Flexible shells and thin films

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 apparatus enhances patient comfort and compliance by providing humidified air at optimal humidity levels, reducing noise and leakage, and improving the overall efficacy of respiratory therapies for various disorders.

Implementation Method 1

a heating element to create vapour from the liquid

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a heating element to create vapour from the liquid

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

a chamber to mix the flow of air with the vapour

Methodology Applied
Scientific EffectMixing:

Implementation Method 4

a liquid trap in the gas flow path

Methodology Applied
Scientific EffectGravity separation: Gravitation

Data Source

PatentEP4081285B1Apparatus for humidifying a respiratory gas
Publication Date: 2025.10.08 RESMED PTY LTD
  • EP4081285B1 patent drawingFigure 1A
  • EP4081285B1 patent drawingFigure 1B
  • EP4081285B1 patent drawingFigure 1C

AI summary

An apparatus is provided to change the absolute humidity of a flow of air for delivery to an entrance of the airways of a patient, the change being compared to the absolute humidity of ambient air. The apparatus has a reservoir configured to hold a volume of liquid. A heating element creates vapour from the liquid. A chamber is provided to mix the flow of air with the vapour. The apparatus has a body having a first wall structure with a chamber inlet port. A closure element having an air inlet port for pneumatically connecting to a source of the flow of air is secured to the body to provide a sealed gas flow path between the air inlet port and the chamber inlet port, and a liquid trap in the gas flow path.