Aircraft Fuel Tank Overflow Pipe Layout for Unusable Fuel Reduction
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Solution Overview
Problem
Aircraft fuel tanks with structural elevations at the bottom, such as those formed by the fuselage structure, face issues with residual fuel accumulation, leading to kerosene fungus, weight penalties, and reduced capacity due to unusable fuel, which existing solutions like periodic cleaning and chemical treatments are costly and ineffective.
Innovation Solution
A device with overflow pipes and valves that automatically open and close based on fuel pressure, connecting adjacent bays in the tank to equalize fuel levels and minimize unusable fuel, using materials like thermoplastic or metal, and designed to consider aircraft-specific conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liner is provided inside the tank to reduce fuel flow after structural impact, then safety is improved, but unusable fuel accumulates in the lower centre area of the tank
Solution Approach 1:
The tank bottom is divided into multiple bays by separation walls with integrated overflow pipes. Each bay can drain independently through its own overflow pipe, preventing fuel accumulation in any single area while maintaining the protective liner structure.
Solution Approach 2:
The overflow pipes extend vertically from the bottom of one bay across the separation wall to the bottom of the other bay, creating a three-dimensional drainage path that bypasses the liner barrier and enables fuel removal from areas previously trapped by the liner's fuel-flow reduction effect.
2Object-affected harmful factors
If periodic cleaning and chemical treatments are applied to the tank, then kerosene fungus growth is reduced, but maintenance costs increase
Solution Approach 1:
The overflow pipes actively extract residual fuel from all bay areas, removing the substrate that supports kerosene fungus growth. By eliminating the root cause (residual fuel), the need for chemical treatments and periodic cleaning is reduced.
Solution Approach 2:
The tank's drainage system serves itself by using the overflow pipes to automatically remove residual fuel during normal fuel extraction operations, without requiring external intervention for cleaning or treatment.
3Strength
If elevations are formed at the bottom of the tank to create bays, then structural strength is improved, but residual fuel accumulates in the bays
Solution Approach 1:
The separation walls serving as structural elevations are merged with the overflow pipe system. The overflow pipes are integrated into the separation walls, allowing the same structural elements to serve both load-bearing and fuel drainage functions.
Solution Approach 2:
The separation walls perform multiple functions: providing structural strength as elevations, dividing the tank into bays for structural reinforcement, and serving as mounting structures for overflow pipes that enable residual fuel drainage from all bays.
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
Reduces aircraft weight, minimizes kerosene fungus risk, increases usable tank capacity, and avoids excess residual fuel penalties without additional equipment, enhancing flight range and safety.
Implementation Method 1
the valve being configured to automatically open when the tank is filled with fuel, to release air from the overflow pipe, and to automatically close when the fuel is extracted from the tank
Implementation Method 2
the valve is configured to automatically open when the fuel pressure in the tank reaches a predefined level to release air from the overflow pipe
Implementation Method 3
connecting adjacent bays in the tank to equalize fuel levels and minimize unusable fuel
Data Source
Figure 1
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AI summary
A device and a method for reducing unusable fuel in a tank of an aircraft is provided, wherein the bottom (12) of the tank (11) is divided into at least two adjacent bays (13, 14, 33) by at least one separation wall (15). The device (10) comprises an overflow pipe (17) configured to be mounted in the tank (11) so that it extends from the bottom (18) of one bay (13, 33) across the separation wall (15) to the bottom (19) of the other bay (14, 33). A valve (23) is provided in an opening (21) located in an upper section (22) of the overflow pipe (17). The valve (23) is configured to automatically open when the tank (11) is filled with fuel (16) and to automatically close when the fuel (16) is extracted from the tank (11).