Ejector Bag Evacuation Slide Deployment
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Solution Overview
Problem
Conventional door-mounted emergency evacuation slide systems face issues with slide pack deployment when doors open rapidly, as gravity may not provide sufficient force to prevent jamming or undesirable orientation, especially at high rotational speeds.
Innovation Solution
An ejector bag system is introduced, utilizing a high-pressure gas inflator assembly connected via flexible tubing to inflate an ejector bag positioned within the slide pack, which increases the initial downward velocity of the slide pack by inflating and pushing it against the packboard and reservoir, ensuring timely clearance of the door enclosure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If doors are configured for rapid opening (high rotational speed), then evacuation time is reduced, but slide packs may jam the door or twist into undesirable orientation due to insufficient downward force
Solution Approach 1:
The ejector bag is pre-positioned within the slide pack enclosure and pre-charged with inflation gas. When the door opens rapidly, the ejector bag inflates immediately to provide the necessary downward force on the slide pack, ensuring it deploys reliably before the door completes its rotation and causes jamming or twisting.
Solution Approach 2:
A high-pressure gas cartridge (nitrogen, argon, or other gas) is used to inflate the ejector bag, providing a controlled pneumatic force that pushes the slide pack downward. This pneumatic mechanism ensures consistent and reliable deployment force regardless of door opening speed variations.
2Reliability
If ejector bag volume is increased to provide more downward force, then slide pack deployment reliability improves, but inflation time increases
Solution Approach 1:
The ejector bag is designed with a volume and pressure configuration that provides sufficient downward force on the slide pack without requiring complete inflation. The bag inflates partially to the point where it contacts and pushes the slide pack downward, then stops, achieving reliable deployment without the time penalty of full inflation.
Solution Approach 2:
The system uses high-pressure gas (stored at elevated pressure in the cartridge) to inflate the ejector bag rapidly. By controlling the pressure and volume parameters of the inflation process, the system achieves the necessary force in minimal time, balancing reliability with speed.
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 ejector bag system effectively increases the drop speed of the slide pack, preventing jamming and ensuring proper orientation during rapid door opening, as demonstrated by tests showing reduced drop time when using the ejector bag compared to gravity-only deployment.
Implementation Method 1
The inflator assembly may include a sealed, high-pressure cartridge of nitrogen operating as the inflation gas
Implementation Method 2
Gravity alone usually supplies sufficient force to position a slide pack clear of the opening door
Data Source
AI summary
Evacuation systems including gravity-assist mechanisms are detailed. The systems may facilitate slide pack deployment from, e.g., aircraft doors by increasing an initial downward velocity of a slide pack. The increased velocity assists the pack in clearing an associated enclosure before jamming the opening door or twisting or flipping into an undesirable orientation.