Respiratory Therapy Humidifier Wick for Rapid Humidity Response

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Solution Overview

Problem

Existing respiratory therapy devices face challenges with humidifiers that have long warm-up and cool-down times, slow response times, high thermal mass, and large size, leading to discomfort and reduced patient compliance due to inadequate humidification and thermal management.

Innovation Solution

A humidifier chamber with a profiled humidifier wick and heating element configuration that includes anisotropic wicking, a heating element with zoned control, and a baffle to lengthen airflow path, allowing for rapid humidity adjustment and reduced size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a traditional humidifier with large water reservoir is used, then humidification capacity is improved, but device size and thermal mass increase

Engineering Contradiction:
Improvehumidification capacityVSAvoiddevice size
Core Design Contradiction:
Quantity of substanceVSVolume of stationary object

Solution Approach 1:

The patent employs a porous wick material that capillary-action draws water from a small reservoir and distributes it across a large surface area. This allows a compact device to achieve high humidification capacity through the extensive evaporative surface provided by the porous structure, eliminating the need for large water reservoirs while maintaining effective humidity delivery.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent utilizes a thin-film heating element that provides uniform heat distribution across the wick structure. This thin-film approach enables efficient thermal transfer with minimal thermal mass, allowing rapid response to temperature changes while keeping the overall device size compact, thus resolving the contradiction between humidification capacity and device volume.

Inventive Principle:
Principle #30Flexible shells and thin films

2Stability of the object's composition

If a humidifier with high thermal mass is used, then stable temperature is improved, but response time increases

Engineering Contradiction:
Improvetemperature stabilityVSAvoidresponse time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent implements a dynamic thermal management system with zoned heating elements that can independently adjust temperature in different regions of the wick structure. This dynamic control allows the system to rapidly respond to changing humidity demands while maintaining stable operating temperatures through real-time adjustment, eliminating the delay associated with high thermal mass systems.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the thermal parameters by using thin-film heating elements with low thermal mass instead of traditional high-mass heating systems. This parameter change enables rapid heating and cooling response while the control system maintains temperature stability through feedback regulation, thus achieving both fast response time and temperature stability simultaneously.

Inventive Principle:
Principle #35Parameter changes

3Volume of stationary object

If a compact humidifier design is used, then device size is reduced, but humidification effectiveness decreases

Engineering Contradiction:
Improvedevice sizeVSAvoidhumidification effectiveness
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The patent uses porous wick material that provides an extensive internal surface area within a compact volume. The capillary action distributes water uniformly throughout the porous structure, creating numerous evaporation sites that maintain high humidification effectiveness despite the small overall device size, thus resolving the contradiction between compactness and effectiveness.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent transitions from a two-dimensional surface evaporation model to a three-dimensional volumetric evaporation model using the porous wick structure. This dimensional change allows water to evaporate throughout the entire volume of the wick rather than just from its surface, significantly increasing humidification effectiveness within a compact footprint and eliminating the trade-off between size and performance.

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

4Loss of time

If rapid humidity adjustment is implemented, then response time is improved, but thermal management complexity increases

Engineering Contradiction:
Improveresponse timeVSAvoidthermal management complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent divides the heating system into multiple independent zoned heating elements that can be controlled separately. This segmentation allows different regions of the wick structure to be heated or cooled independently based on real-time humidity demands, enabling rapid response without requiring complex system-wide thermal management, thus resolving the contradiction between fast response and system simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies local quality control by providing different heating characteristics in different zones of the wick structure. Each zone can be optimized for its specific function (e.g., water absorption zone, evaporation zone, drainage zone), allowing rapid localized adjustments to humidity output without complex global thermal management, thus achieving fast response time with simplified control architecture.

Inventive Principle:
Principle #3Local quality

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 provides improved comfort, faster response times, and compact design, enhancing patient compliance and therapy efficacy by ensuring consistent humidity delivery.

Implementation Method 1

the heating element is configured to heat the humidifier wick to vaporise the second volume of water to add absolute humidity to the flow of air

Methodology Applied
Scientific EffectVaporisation: Evaporation

Implementation Method 2

a humidifier wick configured to retain a second volume of water and the humidifier wick having a profiled shape to substantially enclose at least a portion of the flow path for the flow of air

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP4039313B1A humidifier for a respiratory therapy device
Publication Date: 2025.07.09 RESMED PTY LTD
  • EP4039313B1 patent drawingFigure 1A
  • EP4039313B1 patent drawingFigure 1B
  • EP4039313B1 patent drawingFigure 1C

AI summary

The present invention relates to a humidifier (5000) for a respiratory pressure therapy device. The humidifier comprises a humidifier chamber (5200) comprising a housing (5202) with an air inlet (5002), an air outlet (5004) and an air flow path from the air inlet to the air outlet. A humidifier wick (5230) is positioned within the humidifier chamber, the humidifier wick being configured to retain a volume of water and shaped to substantially enclose at least a portion of the flow path. A heating element (5220) configured to heat the humidifier wick to vaporise the volume of water into the humidification chamber to add moisture to the flow of air. The humidifier wick comprises a heated region (5230H) in thermal contact with the heating element and an unheated region (5230U, 5230D) located upstream and/or downstream of the heating element and the heated region.