Inflation System Pressure Regulator Leakage Vent
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Solution Overview
Problem
Conventional aircraft evacuation slide inflation systems face issues with high temperature gas causing sagging or melting of slides, weight penalties with stored compressed gas, and susceptibility to mechanical failures and pressure regulation leaks, leading to inefficient and unreliable evacuation processes.
Innovation Solution
A control valve system with a slide valve and pressure regulator that includes a flow metering element, allowing for precise regulation of gas flow and pressure, venting excess gas and providing robust flow control to prevent over-pressure and ensure reliable inflation of evacuation slides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pyrotechnic gas generators are used to inflate the evacuation slide, then high volume of gas is produced quickly, but the high temperature gas causes sagging, melting, or scorching of the slide fabric
Solution Approach 1:
A heat exchanger is introduced as an intermediary component between the pyrotechnic gas generator and the evacuation slide. The heat exchanger cools the high-temperature inflation gas before it contacts the slide fabric, preventing thermal damage while maintaining rapid inflation capability. This resolves the contradiction by mediating the harmful thermal effect while preserving the beneficial rapid gas generation.
Solution Approach 2:
The high-temperature gas from the pyrotechnic generator, which initially causes harm, is converted into a benefit through the heat exchanger that also condenses moisture from the gas. The thermal energy that would damage the slide is instead used to drive condensation of water vapor, removing moisture that could freeze and block the system, thereby converting a harmful thermal effect into a useful moisture removal function.
2Ease of operation
If stored compressed gas is used to inflate the evacuation slide, then simple system operation is achieved, but weight penalty increases due to required pressure vessel capacity
Solution Approach 1:
The system merges two gas generation approaches by combining a pyrotechnic gas generator with a smaller stored compressed gas pressure vessel. The pyrotechnic generator provides the majority of inflation gas with minimal weight, while the small pressure vessel supplies supplementary gas to ensure complete inflation. This combination achieves the simplicity of stored gas systems while dramatically reducing the weight penalty associated with large pressure vessels.
3Device complexity
If only stored compressed gas is used for inflation, then system simplicity is maintained, but large temperature drop causes ice formation that blocks gas flow
Solution Approach 1:
A heat exchanger is introduced as an intermediary between the gas source and the slide inflation system. The heat exchanger pre-heats the compressed gas before expansion, preventing the temperature drop that would cause ice formation. This maintains system simplicity while ensuring reliable gas flow by eliminating the ice blockage problem.
4Device complexity
If conventional pressure regulating valve is used, then basic pressure control is achieved, but mechanical failures or trigger failures result in high pressure flow to the slide
Solution Approach 1:
The pressure regulating valve incorporates a feedback mechanism where downstream pressure variations influence the position of the metering element. This creates a self-regulating system that automatically adjusts to maintain safe pressure levels, providing redundancy against mechanical or trigger failures. The feedback loop ensures that even if the primary triggering mechanism fails, the pressure regulation system will prevent hazardous high-pressure flow to the slide.
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 control valve system ensures reliable and efficient inflation of evacuation slides by managing excess gas and preventing over-pressure, reducing the risk of mechanical failures and improving the robustness of the inflation process, thus enhancing passenger safety during emergencies.
Implementation Method 1
A pressure regulator is arranged upstream from and in fluid communication with the slide valve and is operably coupled to a fluid source. The pressure regulator includes a flow metering element movable between an open position and a closed position to regulate a flow of fluid and pressure through the control valve in response to a pressure variations within the downstream slide valve.
Implementation Method 2
a slide valve having a slide movable within a channel between a first position and a second position. When the slide is in the second position, the channel is arranged in fluid communication with an outlet line.
Data Source
AI summary
A control valve includes a slide valve having a slide movable within a channel between a first position and a second position. When the slide is in the second position, the channel is arranged in fluid communication with an outlet line. A pressure regulator is arranged upstream from and in fluid communication with the slide valve and is operably coupled to a fluid source. The pressure regulator includes a flow metering element movable between an open position and a closed position to regulate a flow of fluid and pressure through the control valve in response to a pressure variations within the downstream slide valve.