Breakable Lid Pivoting Mechanism for Firefighting Fluid Ejection

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Solution Overview

Problem

Firefighting fluid ejection devices face reliability issues due to valve systems with moving parts and sealing constraints, leading to high maintenance costs and potential operational failures under severe environmental conditions.

Innovation Solution

A breakable lid with a pivot axis perpendicular to the ejection flow and an eccentric connection, featuring a weakened zone for complete rupture and minimal debris formation, reduces moving parts and pressure drops, ensuring reliable fluid ejection with reduced maintenance needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If a valve system with moving parts and sealing constraints is used to control fluid ejection, then the device can remain inactive for long periods under severe environmental conditions, but the reliability decreases due to potential operational failures and high maintenance costs

Engineering Contradiction:
Improveinactive periodVSAvoidoperational reliability
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The invention removes the valve system with moving parts and sealing constraints from the fluid ejection device. Instead of using a controllable valve, the patent employs a breakable lid that is ruptured by pressure or external action to initiate fluid ejection. This extraction of the problematic valve mechanism eliminates the sources of reliability issues while maintaining the ability to control fluid release through alternative means.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a strainer with fine meshes is installed downstream of the outlet to collect debris from seal breakage, then debris obstruction is prevented, but pressure drop increases which is detrimental to ejection efficiency

Engineering Contradiction:
Improvedebris preventionVSAvoidpressure drop
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The invention converts the harmful effect of debris generation into a beneficial outcome by designing the lid breakage mechanism to produce minimal debris. The lid is configured to break into large fragments that are easily managed, and the breakage location and method are optimized so that debris is naturally directed away from the distribution circuit. This approach eliminates the need for fine mesh strainers and their associated pressure drops.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The lid is designed with specific geometric features and material properties that cause it to segment into controlled large fragments upon breakage rather than shattering into fine debris. This segmentation strategy ensures that the broken pieces are manageable in size and can be easily removed or redirected, preventing obstruction without requiring complex filtration systems.

Inventive Principle:
Principle #1Segmentation

3Object-affected harmful factors

If the lid breakage produces small debris to prevent obstruction, then the distribution circuit is protected, but the strainer becomes a necessary obstacle that disturbs flow and generates pressure drop

Engineering Contradiction:
Improvedebris obstructionVSAvoidejection efficiency
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The invention transforms the potential harm of lid breakage debris into a beneficial situation by designing the lid and its breakage mechanism to produce minimal problematic debris in the first place. The lid geometry, material selection, and breakage initiation points are optimized to create large, manageable fragments that naturally follow the fluid flow without requiring intervention from filtration systems.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 enhances the reliability and efficiency of fluid ejection devices by minimizing load losses and debris formation, making them suitable for critical safety applications like firefighting systems.

Implementation Method 1

The means forming a pivot having an axis perpendicular to the ejection flow, the broken part of the lid naturally aligns with the flow so as to minimize load losses.

Methodology Applied
Scientific EffectHydrodynamic effect:

Implementation Method 2

the weakened zone, capable of promoting rupture of the seal, extends over the entire periphery of the latter. This configuration makes it possible to promote the rupture in pure shear of the lid under the effect of the pressure threshold

Methodology Applied
Scientific EffectShear stress: Shear Stress

Data Source

PatentEP2251065B1Divisible lid for a fluid ejection device
Publication Date: 2018.07.04 AIRBUS OPERATIONS (SAS)
  • EP2251065B1 patent drawingFigure 1~2
  • EP2251065B1 patent drawingFigure 3~5B
  • EP2251065B1 patent drawingFigure 6A~6C

AI summary

The lid has a metallic foil sheet including a peripheral zone constituting a weakened zone that is broken for defined pressure of fluid e.g. Novec 1230(RTM: fire protection fluid). An axle is integrated to the lid and is arranged perpendicular to ejection flow (11) of fluid traversing an ejection orifice (2). The axle forms a pivot connection with a fluid passage pipe. A guiding unit guides, in translation, the axle parallel to the flow of fluid traversing the orifice. The sheet is clasped between two flanges (303) by a screw.