Portable LOX Generation With Cryogenic Air Separation

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Solution Overview

Problem

Conventional portable oxygen systems, whether compressed gaseous or liquid oxygen (LOX), face limitations such as short duration, weight, and obtrusiveness, with LOX systems requiring regular refilling from dewars, which can be inconvenient.

Innovation Solution

A system and method for generating liquid oxygen (LOX) through cryogenic separation of air, using a mobile base unit with components like a compressor, purifier, recuperative heat exchanger, cryocooler, and distillation unit to produce LOX, which can be stored and delivered to a patient portable unit, with byproducts reused for heat transfer to enhance efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If compressed gaseous oxygen is stored in a portable container, then oxygen can be delivered to the patient, but the system becomes heavy and obtrusive, limiting patient mobility

Engineering Contradiction:
Improvepatient mobilityVSAvoidportable oxygen system weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent changes the physical state of oxygen from gaseous to liquid form, which dramatically reduces the volume and weight of the storage container while maintaining the same oxygen supply capacity. This allows the portable unit to be much lighter and less obtrusive for patient wear.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system uses a vacuum-insulated container (thermos principle) to maintain liquid oxygen in a portable, lightweight design. The insulation system allows liquid oxygen to be stored without heavy active cooling, enabling patient-portable operation.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Weight of moving object

If liquid oxygen is stored in a portable container, then the system size and weight are reduced, but the container requires regular refilling from dewars by truck delivery

Engineering Contradiction:
Improveportable oxygen system weightVSAvoidrefilling convenience
Core Design Contradiction:
Weight of moving objectVSEase of operation

Solution Approach 1:

The base unit automatically generates liquid oxygen from ambient air through cryogenic separation, eliminating the need for manual refilling from external dewars. The system serves itself by continuously producing LOX and transferring it to portable units as needed.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The base unit pre-generates and stores liquid oxygen in advance, so that portable units can be refilled on-demand without requiring external delivery services. This preliminary production action eliminates the refilling inconvenience.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If a full portable compressed oxygen container is used, then oxygen can be delivered to the patient, but it lasts for a relatively short period of time

Engineering Contradiction:
Improveoxygen delivery capabilityVSAvoidcontainer usage duration
Core Design Contradiction:
ProductivityVSDuration of action of moving object

Solution Approach 1:

By storing oxygen in liquid form rather than compressed gas, the system achieves much higher density. A portable liquid oxygen container provides significantly longer usage duration (hours to days) compared to compressed gas containers of similar weight and size.

Inventive Principle:
Principle #35Parameter changes

4Ease of operation

If the base unit generates liquid oxygen through cryogenic separation, then frequent refilling is eliminated, but the system requires multiple components including compressor, purifier, heat exchanger, cryocooler, and distillation unit

Engineering Contradiction:
Improverefilling frequencyVSAvoidbase unit component count
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent integrates multiple functions (compression, purification, cooling, separation, and storage) into a single base unit system. This consolidation manages the complexity by creating a unified automated platform that eliminates refilling operations, despite the multiple internal components.

Inventive Principle:
Principle #5Merging (Combining)

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

This approach provides a more portable, efficient, and longer-lasting oxygen supply, reducing the need for frequent refilling and improving mobility, as the system generates LOX on-demand and utilizes byproducts for heat exchange, optimizing energy consumption and system size.

Implementation Method 1

a compressor configured to receive air and pressurize the air

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

a purifier configured to remove impurities from the pressurized air

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 3

a recuperative heat exchanger configured to cool the purified air by transferring heat from the purified air to at least one cold byproduct flow

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 4

a cryocooler configured to receive cooled air from the recuperative heat exchanger and further cool the air to cryogenic temperatures

Methodology Applied
Scientific EffectCryogenic cooling: Cryogenics

Implementation Method 5

a distillation unit configured to separate the cryogenic air into multiple products, including LOX and one or more byproducts

Methodology Applied
Scientific EffectCryogenic distillation: Distillation

Data Source

PatentEP2342518B1Systems and methods for generating liquid oxygen for portable use
Publication Date: 2014.04.09 CAIRE INC
  • EP2342518B1 patent drawingFigure 1~9
  • EP2342518B1 patent drawingFigure 2~3
  • EP2342518B1 patent drawingFigure 4

AI summary

A system for generating liquid oxygen (LOX) for portable use by a patient includes a patient portable unit configured to store LOX and deliver gaseous oxygen (GOX) to the patient, and a mobile base unit configured to generate LOX by cryogenic separation of air and deliver the generated LOX to the patient portable unit. The mobile base unit includes a compressor that receives and pressurizes air, a purifier that removes impurities from the pressurized air, a heat exchanger that cools the purified air, a cryocooler that further cools the air to cryogenic temperatures, and a distillation unit that separates the cryogenic air into multiple products, including LOX and one or more cold byproducts. The separated LOX is communicated toward storage, and at least one of the cold byproducts is passed through the heat exchanger to facilitate heat transfer from incoming purified air to the at least one cold byproduct in order to cool the purified air.