Hydrogen Vent Flame Detection with Removable Ablative Carbon

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Solution Overview

Problem

Existing methods for detecting hydrogen flames on aircraft are unreliable, bulky, and require significant modifications, posing safety risks due to the invisibility of hydrogen flames and the need for constant power supplies.

Innovation Solution

A removable member made of ablative material, such as carbon, is secured to the hydrogen flow path to visually indicate the presence of a hydrogen flame by ablating and producing a visible flame, eliminating the need for power supplies and allowing easy replacement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a tall metal chimney is used to vent hydrogen, then the hydrogen flame safety is improved by channeling hydrogen away from danger areas, but the device weight and size increase significantly making it unworkable for aircraft

Engineering Contradiction:
Improvehydrogen flame safetyVSAvoidchimney weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of moving object

Solution Approach 1:

The invention extracts the flame detection function from the venting system itself and places it on a separate removable member that can be independently positioned and replaced. This separates the safety function (venting) from the detection function (flame visibility), allowing each to be optimized independently without the weight penalty of a tall chimney structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses a flame-colouring liquid or material on the removable member to change the visual appearance of the hydrogen flame from invisible to visible. This allows personnel to detect the presence of a hydrogen flame without requiring a tall chimney structure, resolving the contradiction between safety and weight.

Inventive Principle:
Principle #32Color changes

2Difficulty of detecting and measuring

If flame-colouring liquid is used to make hydrogen flame visible, then the flame detection capability is improved, but the device complexity increases due to monitoring requirements and additional mass

Engineering Contradiction:
Improveflame detection capabilityVSAvoidmonitoring system complexity
Core Design Contradiction:
Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The removable member with flame-colouring material is designed as a disposable or easily replaceable component. Rather than implementing a complex monitoring system to track liquid levels or system status, the invention uses a simple consumable material that depletes over time and can be easily replaced, reducing both complexity and mass.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The flame-colouring material on the removable member automatically serves its detection function without requiring external monitoring systems. The material itself provides the visual indication through its chemical reaction with the flame, making the system self-indicating and eliminating the need for additional sensors or monitoring equipment.

Inventive Principle:
Principle #25Self-service

3Difficulty of detecting and measuring

If electronic sensors or infrared cameras are used to detect hydrogen flames, then the flame detection capability is improved, but the reliability decreases due to power supply requirements and potential failure risks

Engineering Contradiction:
Improveflame detection capabilityVSAvoiddetection system reliability
Core Design Contradiction:
Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The invention replaces electronic detection systems (sensors, cameras) with a passive chemical/physical indication system. The flame-colouring material provides visual detection through direct chemical interaction with the hydrogen flame, eliminating the need for power supplies, electronic circuits, and associated failure risks, thereby significantly improving reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The removable member with flame-colouring material is designed as a simple, passive detection element that requires no power or complex electronics. Its simplicity and lack of electronic components eliminate power supply requirements and electronic failure modes, providing more reliable detection than electronic systems.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Weight of moving object

If a removable member with ablative material is used to detect hydrogen flames, then the device weight is reduced and ease of maintenance is improved, but the flame detection visibility may be compromised without adequate material composition

Engineering Contradiction:
Improvedetection device weightVSAvoidflame visibility
Core Design Contradiction:
Weight of moving objectVSDifficulty of detecting and measuring

Solution Approach 1:

The removable member is constructed from composite materials that combine lightweight properties with effective flame-colouring capabilities. The material composition is specifically designed to provide both weight reduction and adequate flame visibility through the ablative process, resolving the contradiction between light weight and detection effectiveness.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention optimizes the material parameters (composition, particle size, concentration of flame-colouring agents) of the removable member to ensure adequate flame visibility while maintaining lightweight properties. By carefully controlling these parameters, the system achieves both weight reduction and effective detection capability.

Inventive Principle:
Principle #35Parameter changes

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

Provides a lightweight, reliable, and easy-to-maintain method for visually detecting hydrogen flames on aircraft, enhancing safety by making flames visible to the naked eye without electronic aids.

Implementation Method 1

The removeable member comprises a material configured to ablate in the presence of a hydrogen flame. Interaction of said material and the hydrogen flame may provide a visual indicator of the presence of a hydrogen flame.

Methodology Applied
Scientific EffectAblation: Ablation

Implementation Method 2

burning hydrogen is not readily visible with the naked eye... An exposed hydrogen flame, being so difficult to see with the naked eye, represents a significant safety risk.

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4667362A1Improvements in hydrogen flame detection
Publication Date: 2025.12.24 AIRBUS OPERATIONS LTD
  • EP4667362A1 patent drawingFigure 1
  • EP4667362A1 patent drawingFigure 2~3
  • EP4667362A1 patent drawingFigure 4

AI summary

A device 120 comprising a layer 146 of resin-encapsulated carbon is disposed in the vicinity of an outlet 134 of a hydrogen vent 116. The vent 116 carries gaseous hydrogen from a hydrogen store 110 on an aircraft 100, to a location external of the aircraft 100. Upon pressure-relief of the hydrogen store 100, hydrogen travels through the vent 116 and out the outlet 134. In the event of ignition of the hydrogen, the heat of the hydrogen flame melts the resin and releases the carbon. The carbon combusts in the hydrogen flame, thus producing a visible flame. The device 120 is easily removeable and replaceable.