Aircraft Wastewater Drain Assembly With Tolerance Compensation
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Solution Overview
Problem
The existing wastewater tank arrangements in aircraft face challenges in effectively compensating for installation and manufacturing tolerances between the wastewater tank and the service panel, particularly due to deformation caused by flight maneuvers, which conventional flexible drain pipes cannot adequately address without increasing length and weight.
Innovation Solution
A tolerance compensation device comprising a first and second pipe section, where the second pipe section is movable relative to the first pipe section perpendicular to the longitudinal axis, allowing for compensation of tolerances during initial installation, and can be fixed or remain movable for operational flexibility, utilizing a flange and gap configuration for adjustment and a bellows design for flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible drain pipe is used to compensate for deformation tolerances, then deformation tolerances can be compensated, but installation and manufacturing tolerances cannot be effectively compensated without increasing pipe length and weight
Solution Approach 1:
The drain pipe is divided into multiple sections: a first pipe section, a second pipe section with bellows, and a third pipe section. Each section serves a specific function - the bellows section handles installation and manufacturing tolerances, while the flexible third section compensates for deformation tolerances. This segmentation allows each component to be optimized for its specific purpose without compromising overall performance.
Solution Approach 2:
The bellows structure acts as an intermediary component between the rigid first pipe section and the flexible third pipe section. It specifically addresses installation and manufacturing tolerances by providing adjustable compensation through its expandable and collapsible structure, while allowing the third section to handle deformation tolerances.
2Adaptability or versatility
If a long flexible drain pipe is used to compensate for all tolerances, then both installation/manufacturing tolerances and deformation tolerances can be compensated, but weight and space requirements increase
Solution Approach 1:
The drain pipe is divided into multiple sections with different flexibility characteristics. The bellows section (second pipe section) handles installation and manufacturing tolerances with minimal length, while the flexible third section compensates for deformation tolerances. This segmentation eliminates the need for a single long flexible pipe, reducing overall weight and space requirements.
Solution Approach 2:
Different sections of the drain pipe have different quality characteristics - the bellows section provides localized compensation for installation tolerances where needed, while the rigid first section maintains structural integrity. This local differentiation allows each part to be optimized for its specific function without unnecessary weight throughout the entire pipe length.
3Weight of stationary object
If a short rigid drain pipe is used for compact design, then space and weight are saved, but tolerance compensation capability is lost
Solution Approach 1:
The drain pipe system incorporates localized flexible elements (bellows and flexible third section) at specific positions where tolerance compensation is needed, while maintaining rigid sections for structural integrity and compact overall design. This allows the pipe to be short and light overall while still providing necessary compensation capabilities at critical locations.
Solution Approach 2:
The bellows structure uses flexible material that can expand and collapse to compensate for installation and manufacturing tolerances, while the third pipe section uses flexible material to compensate for deformation tolerances. These flexible elements are integrated into an otherwise compact rigid structure, providing tolerance compensation without significantly increasing overall size or weight.
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 solution enables effective compensation of installation and manufacturing tolerances during initial installation without relying on the flexibility of the drain pipe, allowing for a compact and efficient design with a short, rigid drain pipe, while also accommodating deformation tolerances through the flexible second pipe section.
Implementation Method 1
The second pipe section (27) is flexible, i.e. movable or deformable... The second pipe section is designed as a bellows which, viewed along the longitudinal axis (29), has at least one fold (67)
Implementation Method 2
The first pipe section (25) has a gap (33) extending perpendicular to the longitudinal axis (29)... The second pipe section (27) has a flange (35) extending outwards perpendicular to the longitudinal axis (29)... the flange (35) is arranged in the gap (33), so that movement of the second pipe section (27) relative to the first pipe section (25) perpendicular to the longitudinal axis (29) is possible within the gap (33)
Implementation Method 3
The drain pipe (11) serves to empty the waste water tank (9)... The drain pipe (11) extends with its lower second end (15) in a funnel shape into the upper opening at the upper second end (32) of the second pipe section (27)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A wastewater tank assembly (7) for an aircraft (1) is shown and described, comprising a wastewater tank (9) and a drain pipe (11) with a first end (13) and an opposing second end (15), wherein the drain pipe (11) is attached to the wastewater tank (9) at its first end (13) and is provided at its second end (15) for connection to a service panel (17) in the aircraft structure. The objective of providing a wastewater tank assembly that can effectively compensate for tolerances between the wastewater tank and the service panel, in particular installation and manufacturing tolerances during initial installation, is achieved by the wastewater tank assembly (7) having a tolerance compensation device (23) configured to connect the second end (15) of the drain pipe (11) to the service panel (17) and to compensate for tolerances between the second end (15) of the drain pipe (11) and the service panel (17).