Cryogenic Flame Arrestor for Low-Pressure-Loss Flow

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Solution Overview

Problem

Existing flame arrestors have a high density of quenching elements that impede fluid flow and increase weight, which is undesirable in applications requiring minimal pressure loss and reduced weight, such as in aircraft.

Innovation Solution

A flame arrestor with a quenching element cooled to cryogenic temperatures using various cooling methods, including liquid nitrogen, thermoelectric Peltier coolers, and chemical reactions, to maintain the quenching element below the ignition temperature of the combustible fluid, thereby reducing the required quenching surface area and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high density of quenching elements is used to quench the flame, then flame arrest effectiveness is improved, but fluid flow is reduced and weight increases

Engineering Contradiction:
Improveflame arrest effectivenessVSAvoidweight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies parameter changes by cooling the quenching element to cryogenic temperatures (below -50°C, preferably below -100°C). This temperature parameter change reduces the quenching distance required, allowing the use of fewer quenching elements while maintaining flame arrest effectiveness, thereby reducing weight

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces a temperature dimension to the traditional quenching element design. By adding active cooling systems (such as Peltier coolers, liquid nitrogen systems, or endothermic chemical reactions), the quenching element operates in a different thermal dimension, achieving better flame arrest with reduced structural mass

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If a high density of quenching elements is used to quench the flame, then flame arrest effectiveness is improved, but fluid flow is reduced

Engineering Contradiction:
Improveflame arrest effectivenessVSAvoidfluid flow
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

By changing the temperature parameter of the quenching element to cryogenic levels, the patent reduces the required quenching surface area and number of elements, thereby maintaining flame arrest effectiveness while significantly improving fluid flow through the device

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The cooling system performs preliminary action by pre-cooling the quenhing element before flame contact. This advance preparation allows the quenching element to be less dense while still achieving effective flame arrest, thus maintaining high fluid flow rates

Inventive Principle:
Principle #10Preliminary action

3Weight of moving object

If the quenching element is cooled to cryogenic temperatures, then the required quenching surface area is reduced and weight is reduced, but additional cooling system complexity is added

Engineering Contradiction:
ImproveweightVSAvoidcooling system complexity
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent employs self-service principles through passive cooling methods where possible, such as using the cold atmosphere of fuel storage tanks to cool the quenching element, or utilizing endothermic chemical reactions that absorb heat without requiring external power sources or complex control systems

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent uses intermediary substances or systems to achieve cooling, such as liquid nitrogen as a cooling medium, or endothermic chemical reactions that act as thermal intermediaries, absorbing excess heat from the quenching element without requiring direct mechanical cooling systems

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution provides efficient flame arrest without significant pressure loss and weight reduction, allowing for larger flow rates and safer operation in weight-sensitive environments.

Implementation Method 1

a cooling system in thermal contact with the quenching system, wherein the cooling system cools the quenching element during operation of the cooling system

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

a hollow component filled or partially filled with a cooling fluid that flows through the cooling element to extract heat from the quenching element

Methodology Applied
Scientific EffectHeat extraction through fluid flow: Convection

Implementation Method 3

the quenching element has channels in which walls of the channels have a number of dimensions that are selected to reduce a temperature of the combustible fluid below an ignition temperature of the combustible fluid

Methodology Applied
Scientific EffectHeat transfer through channels: Convection

Data Source

PatentEP3679989B1Flame arrestor
Publication Date: 2025.12.31 THE BOEING CO
  • EP3679989B1 patent drawingFigure 1
  • EP3679989B1 patent drawingFigure 2~3
  • EP3679989B1 patent drawingFigure 4

AI summary

A method, system, and apparatus for flame arresting are provided. In an example, a flame arrestor (1302) includes a quenching element (1308) disposed within a conduit (1301). The flame arrestor (1302) also includes a cooling system (1306) in thermal contact with the quenching system (1308). The cooling system cools the quenching element (1308) during operation of the cooling system (1306).