Drain Mast Seal Segregated Chambers APU Interface
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Solution Overview
Problem
Traditional solutions for preventing the ingestion of flammable or odorous fumes by inlet drain lines in turbomachines, such as aircraft auxiliary power units (APU), increase space, weight, and complexity, and are not effective in maintaining a fluidly segregated environment for air and effluent drain lines.
Innovation Solution
A drain mast seal with a continuous wall and ceiling forming segregated chambers, where a barrier with a tab extends downward from the ceiling at an angle to separate the chambers, allowing for fluid segregation without significantly increasing compressive load or space, and is designed to support drain lines without external clamps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional solutions (spacing, multiple seals, check valves) are used to prevent fume ingestion by inlet drain lines, then fluid segregation is improved, but device complexity, space, weight, and cost increase
Solution Approach 1:
The seal is divided into multiple independent chambers (first chamber for inlet drain lines, second chamber for effluent drain lines) separated by a barrier. This segmentation allows fluid segregation without requiring multiple separate seals or complex valve systems, as each chamber independently contains its respective fluid path.
Solution Approach 2:
Multiple functions are merged into a single seal structure: fluid segregation, structural support for drain lines, and compression sealing. The barrier simultaneously divides chambers and provides support surfaces, eliminating the need for external clamps or additional support components.
2Reliability
If barrier extends downward from ceiling at angle to separate chambers, then fluid segregation is achieved, but compressive load increases
Solution Approach 1:
The barrier extends downward from the ceiling at an angle, utilizing the vertical dimension to create fluid segregation. This angular extension achieves effective separation while distributing compressive forces across a larger area, reducing the peak compressive load compared to a horizontal barrier configuration.
3Device complexity
If drain lines are supported without external clamps, then device complexity is reduced, but the seal structure must bear additional load
Solution Approach 1:
The barrier is designed to simultaneously perform fluid segregation and structural support functions. By integrating the support function into the barrier structure itself, external clamps are eliminated, reducing device complexity while the seal structure assumes the additional load.
Data Source
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AI summary
A single drain mast seal that provides a fluidly segregated internal chamber for air inlet drain lines is provided. The provided drain mast seal does not significantly add to the seal's compressive load and minimizes the seal's three-dimensional space claim. In addition, the provided drain mast seal is formed to sufficiently support associated drain lines without requiring external clamps or hardware components. The provided drain mast seal thereby optimizes the APU-to-drain mast interface.