Portable Liquid Oxygen System for Ambulatory Ventilation
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Solution Overview
Problem
Existing mechanical ventilation therapies lack a portable and ambulatory form factor, making it difficult for patients to receive respiratory support while mobile, due to the size and weight of conventional oxygen supply systems.
Innovation Solution
A portable liquid oxygen system with a rapid gas conversion mode, utilizing a heat exchanger and Stirling engine to efficiently convert liquid oxygen to gas, integrated with a portable ventilator, allowing for adjustable flow rates and modes of operation based on patient needs, and weighing less than 10 pounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional oxygen supply systems (compressed gas cylinders) are used to provide mechanical ventilation, then sufficient oxygen delivery capacity is achieved, but the system weight and size increase significantly, reducing patient mobility
Solution Approach 1:
The patent changes the physical state of oxygen from compressed gas to liquid form, utilizing the higher density of liquid oxygen to achieve the same oxygen delivery capacity with significantly reduced storage volume and weight. The system includes a liquid oxygen reservoir that converts liquid oxygen to gas on-demand through controlled evaporation or heating, providing sufficient oxygen for mechanical ventilation without the bulk of traditional compressed gas cylinders.
2Weight of moving object
If liquid oxygen systems are used to reduce weight and improve portability, then system weight decreases, but the complexity of liquid-to-gas conversion and flow control increases
Solution Approach 1:
The liquid oxygen system is designed to utilize ambient temperature differential for automatic phase change. The liquid oxygen reservoir is thermally isolated but allows controlled heat transfer from the environment, enabling automatic evaporation and gas generation without requiring active heating elements or complex control systems. This self-service approach reduces device complexity while maintaining portability benefits.
3Ease of operation
If portable ventilator design is pursued to enable ambulation, then patient mobility improves, but the ventilator size and power requirements increase
Solution Approach 1:
The ventilation system is segmented into functionally independent modules: a portable ventilator unit, a liquid oxygen reservoir, and a patient interface. The ventilator itself is minimized to essential functions (breath triggering, flow delivery, and basic monitoring), while the oxygen supply is provided separately from the liquid reservoir. This segmentation allows each component to be optimized for portability, with the ventilator being small and lightweight while the oxygen reservoir provides sustained supply capacity.
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 patients to receive mechanical ventilation support while ambulating, increasing portability and convenience, with the system automatically adjusting to meet varying respiratory demands, thus improving patient mobility and quality of life.
Implementation Method 1
A portable liquid oxygen system providing an average flow rate of oxygen gas at approximately 6-approximately 20 lpm using a rapid gas conversion mode. The rapid gas conversion mode may utilize a heater on the heat exchanger.
Implementation Method 2
The rapid gas conversion mode may utilize a Stirling engine passing air from a heat source across the heat exchanger to a heat sink, wherein the heat source is ambient air, and wherein the heat sink is proximal to a liquid oxygen store.
Data Source
AI summary
A portable liquid oxygen system may provide an average flow rate of oxygen gas at approximately 6-approximately 20 lpm using a rapid gas conversion mode. The rapid gas conversion mode utilizes a Stirling engine that harnesses the heat differential between the ambient temperature and the liquid oxygen store to drive a fan. The fan operates to blow ambient air across a heat exchanger, which allows the heat exchanger to more rapidly evaporate liquid oxygen into oxygen gas.