Single-Piece Vent Dam Insert for Small-Aperture Duct Sealing
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Solution Overview
Problem
Existing vent dams for aircraft fuel tanks require multiple pieces, increasing fabrication complexity and fastener count, which complicates installation and may necessitate electrical grounding.
Innovation Solution
A single piece vent dam insert with offset lateral flanges and a curved wall is designed to be rotated and inserted through an aperture in a stringer, allowing for a minimized aperture size and simplified assembly without fasteners, using a fillet seal for a secure fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multi-piece dams are employed to allow collapsed or piecemeal insertion through the aperture, then the insertion difficulty is reduced, but the device complexity and fastener count increase
Solution Approach 1:
The vent dam is designed as a single piece with an asymmetric cross-section that can be collapsed or flexed during insertion, then returns to its rigid sealed form once installed. This segmentation of the insertion process (collapsed state for insertion, rigid state for sealing) resolves the contradiction by allowing easy insertion while maintaining structural integrity and simplicity of the dam itself.
Solution Approach 2:
The vent dam incorporates dynamic characteristics by being designed to flex or collapse during the insertion process through the aperture, then maintain its rigid sealed shape once installed. This dynamic behavior allows the dam to adapt its stiffness characteristics - flexible during insertion, rigid during operation - resolving the contradiction between ease of insertion and structural simplicity.
2Strength
If the aperture size is minimized to maintain structural strength, then the structural strength is improved, but the insertion difficulty increases
Solution Approach 1:
The vent dam's asymmetric cross-section is segmented into dimensions that allow it to be collapsed or flexed along one axis while maintaining its sealing function. This enables the aperture to be minimized for structural strength while the dam can still be inserted by collapsing it along the asymmetric dimension, then expanding to seal once installed.
Solution Approach 2:
The vent dam employs an asymmetric cross-sectional shape with different dimensions in orthogonal directions. This asymmetry allows the aperture to be minimized in the critical structural direction while providing sufficient clearance in the asymmetric direction for insertion. The dam is inserted by exploiting the larger dimension of its asymmetric shape, then oriented to provide the seal.
3Adaptability or versatility
If multi-piece dams with joining fasteners are used, then the insertion flexibility is improved, but the fabrication complexity and electrical grounding requirements increase
Solution Approach 1:
The vent dam merges multiple functions into a single piece: the sealing function, the insertion flexibility, and the structural support are all integrated into one monolithic component. This eliminates the need for joining fasteners and multiple separate pieces, resolving the contradiction by providing insertion flexibility through the single piece's asymmetric geometry rather than through assembly of multiple components.
4Device complexity
If a single piece vent dam is used, then the device complexity is reduced, but the insertion difficulty through the aperture increases
Solution Approach 1:
The single piece vent dam employs an asymmetric cross-sectional shape where one dimension is larger than the others. This asymmetry allows the dam to be inserted by approaching the aperture at a specific angle that exploits the larger dimension for clearance, while maintaining structural integrity and sealing capability in the other dimensions. The asymmetric shape enables rotation into the final sealed position after insertion.
Solution Approach 2:
The single piece vent dam incorporates dynamic insertion capability by being designed to rotate from an insertion angle to a final sealed orientation. During insertion, the dam approaches at an angle that exploits its asymmetric geometry for clearance, then rotates into its final position where it provides the seal. This dynamic insertion process resolves the contradiction between being a simple single piece and being insertable through a minimized aperture.
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A dam for use with a duct (10) having a longitudinal axis (12). The dam employs a single piece insert (14) having a first lateral flange (16) and a second lateral flange (18) configured to engage opposing interior lateral surfaces (20, 22) of the duct (10). The insert (114, 14) engages the duct (10) in sealing contact in a seated position. The first and second lateral flanges (16) are offset longitudinally along the longitudinal axis (12, 15) and joined with a curved wall (24) having a curvature (26) shaped to be received, with the insert (114, 14) oriented at an insert (114, 14) angle (28) about a normal axis (30) perpendicular to the longitudinal axis (12, 15), in an aperture (13) in the duct (10).