Fire Extinguisher Membrane Bag Assembly for Complete Liquid Expulsion

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Solution Overview

Problem

Existing fire extinguishing devices face challenges in efficiently expelling extinguishing liquid to a fire source on mobile platforms with variable trim, particularly due to difficulties in assembly and control of a deformable membrane and pyrotechnic gas generators, which can damage the membrane and lead to incomplete liquid expulsion.

Innovation Solution

A fire extinguishing device with a pyrotechnic gas generator and an inflatable membrane bag connected to the gas outlet, where the bag is folded in a confinement space and expands rearward, driven by a deflector pipe, ensuring complete liquid expulsion and assembly in a single block, with a breakable cap for efficient liquid deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a deformable membrane is used to separate liquid from gas generator, then assembly precision requirements are reduced, but the membrane can be damaged by hot gas and assembly difficulty increases

Engineering Contradiction:
Improvetank internal machining precisionVSAvoidmembrane integrity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The membrane is pre-assembled and sealed to the gas generator outlet within the cap before the gas generator is installed in the tank. This preliminary assembly ensures the membrane is properly positioned and protected before exposure to hot gas, eliminating the need for precision machining of the tank interior while ensuring membrane integrity.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The cap acts as an intermediary structure that houses both the gas generator and the membrane assembly. It provides a controlled environment where the membrane can be safely connected to the gas generator outlet, protecting the membrane from direct exposure to hot gas while maintaining the separation function.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If gas generator is positioned at rear end with all expulsion elements grouped together, then space is minimized and assembly is simplified, but control of liquid expulsion becomes difficult on platforms with variable trim

Engineering Contradiction:
Improvedevice spaceVSAvoidliquid expulsion control
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The membrane is designed to be inflatable and dynamic, capable of changing its shape and position in response to gas pressure. When the gas generator is triggered, the membrane inflates and pushes the liquid forward, ensuring complete expulsion regardless of the device's orientation on the platform. This dynamic adaptation allows the compact rear-positioned design to function effectively in all trim conditions.

Inventive Principle:
Principle #15Dynamics

3Ease of manufacture

If membrane is floating and attached to inner wall, then assembly is simplified, but assembly difficulty increases and liquid expulsion completeness is reduced

Engineering Contradiction:
Improvemembrane attachmentVSAvoidliquid expulsion efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The membrane assembly is merged with the gas generator outlet by sealing the membrane to the outlet within the cap. This unified assembly ensures that when the gas generator operates, the membrane is directly pushed by the gas flow, maximizing liquid expulsion efficiency. The membrane is no longer floating or loosely attached but is integrally connected to the gas generation system.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If deflector is added around gas outlets to protect membrane, then membrane damage is prevented, but device complexity increases

Engineering Contradiction:
Improvemembrane protectionVSAvoiddeflector structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cap serves multiple functions: it houses the gas generator, provides the confinement space for the membrane assembly, and protects the membrane from hot gas exposure. By integrating these functions into a single component, the need for a separate deflector structure is eliminated, maintaining membrane protection while minimizing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Ensures effective and complete expulsion of the extinguishing liquid around the gas generator, preventing liquid trapping and facilitating assembly, even on platforms with varying orientations, while using high-density extinguishing liquids like HFE 7500 without ozone layer risk.

Implementation Method 1

a gas generator (17) installed in the tank at a rear end (23) thereof, to push the liquid towards an expulsion outlet (21) at a front end (22) of the tank under the action of the gas emitted by the gas generator

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Implementation Method 2

the gas generator is a pyrotechnic gas generator emitting combustion gases

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP2683449B1Device for extinguishing a fire
Publication Date: 2015.01.21 PYROALLIANCE
  • EP2683449B1 patent drawingFigure 1~2
  • EP2683449B1 patent drawingFigure 3~5

AI summary

Extinguishing a fire by pressurization of a reservoir that contains an extinguishing liquid. According to the invention, the reservoir containing the liquid is provided with a discharge outlet at a front end, a gas generator (17) is installed at a rear end, and a membrane forming an inflatable bag (19) is installed in the reservoir by being folded up before release in a confined space at the front of the gas generator, of which the outlet is connected to a deflector (47) that comprises an ejector tube (49) oriented towards the rear.