Aircraft Fuel Tank Isolator for Pipe-to-Panel Electrical Separation
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Solution Overview
Problem
In aircraft fuel tanks with irregular shapes, there is a challenge in isolating electrically conductive panels from pipes passing through them to prevent electrical currents from flowing between the panels and pipes, which can lead to static electricity buildup and lightning strikes.
Innovation Solution
An isolator system with counterbores and grooves is used to attach non-electrically conductive components between the panels and pipes, featuring a chemically inert material to prevent electrical arcs and fuel leakage, and utilizing electrically conductive fasteners insulated from the panel and pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pipes pass directly through fuel tank panels, then installation is simple, but electrical currents can flow between panels and pipes causing static electricity buildup and lightning strike risks
Solution Approach 1:
The patent introduces an isolator as an intermediary component that passes through the fuel tank panel and provides both mechanical support for the pipe and electrical isolation. The isolator includes a non-conductive body with an aperture for the pipe, attachment features for securing the pipe, and extends through the panel to provide electrical isolation between the pipe and panel, thus resolving the contradiction between maintaining simple installation and achieving electrical isolation.
2Strength
If electrically conductive fasteners are used to attach the isolator, then structural integrity is maintained, but electrical conduction between panel and pipe occurs
Solution Approach 1:
The isolator acts as a non-conductive intermediary that mechanically connects the pipe to the panel while electrically isolating them. The attachment features (such as ribs, lugs, or flanges) on the isolator body provide secure mechanical attachment points for both the pipe and the panel, maintaining structural integrity without requiring electrically conductive fasteners that would compromise electrical isolation.
Solution Approach 2:
The isolator includes a non-conductive body that can be designed with flexible attachment features such as elastic ribs or deformable lugs that provide secure mechanical attachment while maintaining electrical isolation. These flexible features can deform during installation to ensure tight mechanical connection without needing conductive fasteners.
3Reliability
If the isolator extends significantly through the panel, then electrical isolation is improved, but the isolator interferes with fuel flow in the irregular-shaped tank
Solution Approach 1:
The isolator is designed with local quality variations - the body extends through the panel to provide necessary electrical isolation, but the aperture and overall geometry are optimized to minimize interference with fuel flow. The attachment features are localized to specific regions of the isolator body, allowing electrical isolation function while maintaining unobstructed fuel flow paths in the irregular-shaped tank.
Solution Approach 2:
The isolator provides electrical isolation primarily in the dimensional direction perpendicular to the panel surface (extending through the panel thickness), while minimizing its cross-sectional area in the dimensions parallel to the fuel flow paths. This dimensional differentiation allows the isolator to perform its electrical isolation function effectively without significantly obstructing fuel flow through the tank.
Data Source
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AI summary
Disclosed is an isolation system for an aircraft fuel tank, the isolation system configured to separate an electrically conductive internal panel of the fuel tank from an electrically conductive pipe that passes through the panel. The isolation system comprises: a pipe fitting configured, in use, to receive the pipe, and an isolator configured, in use, to pass through the panel. The isolator comprises: an aperture defined by an outer wall and extending from a first side of the isolator to a second side of the isolator, the aperture configured to receive the pipe fitting in use, and a flange extending from the outer wall of the aperture and on which are positioned a plurality of first attachment points for attaching the isolator to the panel, and a plurality of second attachment points for attaching the isolator to the pipe, wherein the isolator comprises a non-electrically conductive material. Also disclosed is method of isolating an electrically conductive internal panel of an aircraft fuel tank from an electrically conductive pipe that passes through the panel, and an aircraft.