Membrane Humidifier Architecture for Low-Pressure Nasal Insufflation
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Solution Overview
Problem
Conventional high flow therapy systems require high pressure sources due to increased resistance from membrane humidifiers and large bore cannulas, limiting their use in environments without access to pressurized gas, and non-membrane humidifiers fail to effectively flush CO2 and produce lower quality vapor.
Innovation Solution
A low pressure system architecture using a blower, vapor transfer unit with a membrane, and a nasal cannula with separate flow paths and large bore delivery tubes, integrated gas and liquid paths within a single tube, and a flexible film breech lock to maintain system integrity and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a membrane humidifier is used to humidify breathing gas, then vapor quality is improved, but pressure requirements increase due to higher flow resistance
Solution Approach 1:
The liquid delivery line is nested within the gas delivery tube, allowing both fluid paths to share the same external housing and routing infrastructure. This reduces the number of separate components and connections, thereby reducing overall system resistance while maintaining effective humidification through the membrane.
2Productivity
If a small bore nasal cannula is used to increase gas velocity, then CO2 flushing is improved, but pressure requirements increase
Solution Approach 1:
The nasal cannula is designed with separate flow paths for gas delivery and liquid delivery, allowing each function to be optimized independently. The gas path uses a small bore design for high velocity and CO2 flushing, while the liquid path has its own dedicated route to the membrane humidifier, preventing the liquid delivery requirements from increasing the pressure needed for gas delivery.
3Stress or pressure
If a non-membrane humidifier is used to reduce pressure requirements, then system pressure is reduced, but CO2 flushing is insufficient and vapor quality is lower
Solution Approach 1:
A membrane humidifier uses a porous or semi-permeable membrane that allows water vapor to pass through while maintaining a structured flow path. This membrane design enables effective CO2 flushing through controlled diffusion and convection, while also producing high-quality vapor through the membrane's vapor transfer properties, thus resolving the trade-off between pressure requirements and CO2 flushing effectiveness.
4Stress or pressure
If separate gas and liquid paths are used in the delivery tube, then flow resistance is reduced, but system complexity increases
Solution Approach 1:
The liquid delivery line is nested within the gas delivery tube, allowing both fluid paths to share the same external housing and routing infrastructure. This reduces the number of separate components and connections, thereby reducing overall system resistance while maintaining effective humidification through the membrane.
Solution Approach 2:
The gas and liquid delivery systems are merged into a single integrated tube assembly, where the liquid line is positioned within the gas line. This consolidation reduces the number of separate connections and interfaces required, simplifying the overall system architecture while maintaining separate flow paths to minimize resistance.
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
Enables operation with ambient pressure sources, reduces flow resistance, and maintains effective CO2 flushing and vapor quality, allowing use in various environments without pressurized gas availability.
Implementation Method 1
The membrane permits transfer of vapor into the gas passage from liquid in the liquid passage
Implementation Method 2
The base unit includes a blower. The blower delivers breathing gas to the gas passage of the vapor transfer unit
Implementation Method 3
when liquid is in the liquid container, the liquid exerts pressure against the film, which in turn exerts pressure against the breech lock, causing friction
Implementation Method 4
the delivery tube insulates the liquid delivery line from ambient air
Implementation Method 5
The liquid delivery line may carry heated liquid, so insulating the line can reduce the energy required to maintain the temperature of the line
Data Source
AI summary
Systems, methods, and devices for humidifying a breathing gas are presented. The system includes a base unit, a vapor transfer unit, a nasal cannula, and a liquid container. The base unit includes a blower. The vapor transfer unit is external to the base unit and includes a gas passage, a liquid passage, a gas outlet, and a membrane separating the gas passage and the liquid passage. The membrane permits transfer of vapor into the gas passage from liquid in the liquid passage. The nasal cannula is coupled to the gas outlet. The liquid container is configured to reversibly mate with the base unit.