Dual Inflatable Bladder Redundancy for Aircraft Evacuation
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Solution Overview
Problem
In aircraft evacuation assemblies, inflatable components face issues with inadvertent deflation, which can compromise their reliability and safety, especially when functioning as life rafts in emergency situations.
Innovation Solution
The design incorporates dual inflatable bladders with an aspirator inlet valve that entrains ambient air into the first fluid chamber, and a pressure relief valve for fluid communication between the bladders, ensuring redundancy and maintaining a void between them to prevent direct contact and potential puncture, along with flexible spacer elements to maintain separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single inflatable bladder is used, then the device complexity is reduced, but the reliability decreases due to risk of inadvertent deflation
Solution Approach 1:
The inflatable component is divided into two separate inflatable bladders (first and second bladders) that are fluidly isolated from each other. Each bladder can be independently inflated and deflated, allowing one to remain functional even if the other fails, thereby improving reliability while maintaining manageable device complexity through modular design.
Solution Approach 2:
The system incorporates redundant inflatable bladders as a pre-prepared backup mechanism. If one bladder inadvertently deflates or fails, the other bladder is already inflated and ready to provide immediate support, cushioning against the harmful effect of deflation before it compromises safety.
2Reliability
If the first inflatable bladder and second inflatable bladder are in direct contact, then the manufacturing precision is simplified, but the reliability worsens due to potential puncture between bladders
Solution Approach 1:
A fluid barrier (such as a fluid reservoir or fluid layer) is introduced between the first and second inflatable bladders to prevent direct contact. This intermediary layer eliminates the risk of puncture between bladders while maintaining the compact nested configuration, thereby improving reliability without significantly increasing manufacturing complexity.
3Ease of operation
If the pressure relief valve diameter is increased, then the fluid flow between bladders is improved, but the device complexity increases due to larger valve components
Solution Approach 1:
The system allows for adjustment of the pressure relief valve diameter within an optimal range (0.5 to 2 inches) to balance fluid flow requirements with device compactness. By optimizing this parameter, the system achieves adequate fluid transfer between bladders while avoiding excessive valve size that would increase overall device complexity.
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 configuration enhances the reliability of inflatable components by providing dual layer redundancy, preventing inadvertent deflation and ensuring continued functionality even if one bladder fails, thereby maintaining life-saving support for passengers.
Implementation Method 1
The inlet valve is an aspirator configured to entrain air from atmosphere (e.g., ambient air) into the first fluid chamber
Data Source
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AI summary
The inflatable component includes, according to various embodiments, a first inflatable bladder (221) defining a first fluid chamber (222) and a second inflatable bladder (226) defining a second fluid chamber (227). The second inflatable bladder may circumscribe the first inflatable bladder such that the first inflatable bladder is disposed in the second fluid chamber. The inflatable component also includes, according to various embodiments, an inlet valve (224) coupled to the first inflatable bladder and the second inflatable bladder, wherein the inlet valve is configured to deliver fluid to the first fluid chamber. In various embodiments, the inflatable component also includes a pressure relief valve (229) coupled to the first inflatable bladder, wherein fluid communication between the first fluid chamber and the second fluid chamber is via the pressure relief valve.