Microporous Air Separation for Halon-Free Aircraft Fire Suppression

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Solution Overview

Problem

The phase-out of Halon in aircraft fire suppression systems necessitates the development of effective alternatives that can provide both high-rate and low-rate discharge capabilities for fire suppression, while minimizing weight and ensuring reliable inert gas generation.

Innovation Solution

Implementing air separation modules with polymers having inherent microporosity, such as Thermally Rearranged polymers (TRPs) and Polymers of Intrinsic Microporosity (PIMs), to generate nitrogen-enriched inert gas for low-rate discharge fire suppression, combined with a dedicated fire suppression ASM for high throughput inert gas generation during emergencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Halon-based systems are used for fire suppression, then fire suppression capability is maintained, but system weight and environmental harm increase

Engineering Contradiction:
Improvefire suppression capabilityVSAvoidsystem weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the chemical composition parameter from Halon to nitrogen-enriched air, maintaining fire suppression capability while reducing weight and eliminating environmental harm. The inert gas system achieves the same oxygen displacement effect without the drawbacks of Halon.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts the essential fire suppression function (oxygen displacement) from the Halon chemical and implements it using nitrogen-enriched air generated from ambient air, eliminating the need for heavy stored Halon cylinders while maintaining effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If air separation modules with inherent microporosity are used, then inert gas generation efficiency is improved, but membrane complexity increases

Engineering Contradiction:
Improveinert gas generation throughputVSAvoidmembrane structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent employs membranes with inherent microporosity that provide high nitrogen permeance through their porous structure. The microporous material allows efficient nitrogen separation and throughput while the inherent porosity is built into the membrane material itself, reducing the need for complex external structures.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent uses composite membrane structures combining different materials to achieve both high nitrogen selectivity and high permeance. The composite approach integrates the benefits of multiple materials to optimize gas separation performance while managing structural complexity.

Inventive Principle:
Principle #40Composite materials

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 lightweight, high-permeance, and selective inert gas generation, reducing system weight by up to 150-200 pounds compared to Halon-based systems, while ensuring reliable fire suppression capabilities throughout extended flights.

Implementation Method 1

a second air separation module configured to receive pressurized air from the pressurized air source, the second air separation module arranged to generate inert gas from the received pressurize air and supply the generated inert gas to a protected space of the aircraft. The second air separation module comprises a membrane having inherent microporosity.

Methodology Applied
Scientific EffectPermeation: Permeation

Implementation Method 2

The second air separation module comprises a membrane having inherent microporosity

Methodology Applied
Scientific EffectMicroporosity: Porosity

Implementation Method 3

a cooling heat exchanger arranged between the pressurized air source and the first air separation module

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 4

a pressurized air source

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP4321222B1Halon alternatives for aircraft fire suppression
Publication Date: 2025.10.29 HAMILTON SUNDSTRAND CORP
  • EP4321222B1 patent drawingFigure 1A~1B
  • EP4321222B1 patent drawingFigure 2
  • EP4321222B1 patent drawingFigure 3

AI summary

Fire suppression systems for aircraft include an air source (310, 502), a first ASM (328a, 428a, 504) configured to generate inert gas from air from the air source and supply inert gas to a fuel tank, and a second ASM (328b, 428b, 506) configured to generate inert gas from the air from the air source and supply inert gas to a protected space of the aircraft. The second ASM comprises a membrane having inherent microporosity. A controller, in operable communication with the ASMs, is configured to operate the first ASM and not the second ASM during a first state of operation, and in response to a fire detected in the protected space, operate the second ASM to supply an inert gas from the second ASM to the protected space in a second state of operation.