Composite Fuel Tank Access Cover with Conductive Metal Frame
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Solution Overview
Problem
Current structural arrangements for access windows in fuel tanks made of composite materials fail to prevent sparking during electrical discharges and do not effectively prevent fuel accumulation or protect the tank's edges during maintenance.
Innovation Solution
A structural arrangement featuring a continuous metal frame that conducts electric currents safely outside the tank, combined with insulating materials and a sealing ring to prevent sparking and fuel accumulation, while providing protection for the composite coating edges during maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal access lid is used in a composite fuel tank, then structural strength and lightning protection are improved, but sparking inside the tank and fuel accumulation occur
Solution Approach 1:
The access lid system is divided into multiple functional components: an external metal lid for structural strength and lightning protection, an internal lid made of non-conductive composite material to prevent sparking, and a sealing ring to prevent fuel accumulation. Each component addresses specific requirements without compromising the others.
Solution Approach 2:
A sealing ring positioned between the access lid and tank wall serves as an intermediary element that prevents fuel from accumulating in the gap between the lid and tank. The sealing ring made of elastomeric material creates a barrier that stops fuel migration while allowing the metal lid to maintain structural integrity.
2Weight of moving object
If composite materials are used for the tank structure, then weight is reduced, but protection against sparking and electrical discharge is compromised
Solution Approach 1:
The tank structure uses composite materials for weight reduction in non-critical areas, while the access lid system incorporates metal components specifically at the access window location where lightning protection and sparking prevention are critical. This localized use of metal provides targeted protection without significantly increasing overall weight.
Solution Approach 2:
The internal lid is made of composite material that is non-conductive to electricity, preventing sparking while maintaining the overall composite structure of the tank. The combination of composite and metal materials in the access lid system creates a solution that leverages the advantages of both material types.
3Strength
If the access lid is made of metal for structural integrity, then strength is improved, but fuel accumulation on the inner surface occurs
Solution Approach 1:
The access lid system is segmented into external and internal lids with different materials and functions. The internal lid made of non-conductive composite material prevents fuel accumulation by eliminating the conductive surface that would otherwise attract and hold fuel residues.
Solution Approach 2:
The sealing ring acts as an intermediary barrier between the metal access lid and the tank wall, preventing fuel from migrating along the gap and accumulating on the inner surface of the metal lid. This sealing mechanism stops the fuel flow path that would lead to accumulation.
4Object-affected harmful factors
If reinforcement elements are added to protect the coating edges, then protection is improved, but device complexity increases
Solution Approach 1:
The sealing ring serves multiple functions simultaneously: it prevents fuel accumulation, protects the composite coating edges from mechanical damage during maintenance, and maintains the seal between the access lid and tank wall. This multi-functionality avoids the need for separate protection elements.
Solution Approach 2:
The protective function for the coating edges is merged into the sealing ring structure. The sealing ring is positioned to extend over the edge of the composite coating, providing mechanical protection while maintaining its primary sealing function. This integration eliminates the need for separate reinforcement elements.
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
Effectively prevents sparking within the fuel tank and reduces the risk of fuel accumulation at the access window, while safeguarding the composite coating edges from physical damage during maintenance operations.
Implementation Method 1
a continuous metal frame (31) disposed on an internal portion of the fuel tank (20) fastened to the composite coating (40) and internally and perimetrally circumventing the access window (30), the continuous metal frame (31) being cooperative with the external lid (11) in the conduction of an electric current
Implementation Method 2
an electrical insulation layer disposed directly in the internal portion of the tank structure
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
There is disclosed a structural arrangement (10) for an access window (30) to a fuel tank (20) with composite coating (40), this structural arrangement (10) comprising an external lid (11) associated to the access window (30) by fastening means (12), the structural arrangement (10) for an access window (30) to a fuel tank (20) with composite coating (40) further comprising a continuous metal frame (31) disposed on an internal portion of the fuel tank (20), fastened to the composite coating (40) internally and perimetrally circumventing the access window (30), the continuous metal frame (31) being cooperative with the external lid (11) in the conduction of an electric current.