Capacitive Fuel Gauge Static Dissipation
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Solution Overview
Problem
In aircraft fuel tanks, capacitive level gauges with insulator-based structural bodies face issues with static electrification leading to potential fuel ignition due to the streaming electrification phenomenon, especially when using glass-fiber reinforced plastic (GFRP) materials.
Innovation Solution
A capacitive level gauge design featuring insulator-based columnar and hollow-cylindrical structural bodies with outer and inner electrodes, where the structural bodies incorporate communicating portions such as through-holes or conductors to allow electric charge to move from the surface to the electrodes, preventing static electrification from accumulating and reducing the risk of electric discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulator materials (such as GFRP) are used for cylindrical structural bodies to achieve weight reduction and environmental resistance enhancement, then the structural bodies gain improved environmental resistance and weight characteristics, but static electrification occurs during fuel flow causing safety risks due to accumulated electric charge
Solution Approach 1:
A conductive layer is introduced as an intermediary between the insulator material (cylindrical structural body) and the fuel. This conductive layer serves as a mediator that allows electric charge to pass through while maintaining the insulator's weight reduction and environmental resistance benefits. The conductive layer prevents static electrification accumulation by providing a charge dissipation path without compromising the structural integrity or environmental resistance of the insulator material.
2Weight of moving object
If insulator materials are used for structural bodies, then weight is reduced and environmental resistance is enhanced, but electric charge accumulates on the surface leading to potential electric discharge and fuel ignition
Solution Approach 1:
A conductive layer is introduced as an intermediary between the insulator material (cylindrical structural body) and the fuel. This conductive layer serves as a mediator that allows electric charge to pass through while maintaining the insulator's weight reduction and environmental resistance benefits. The conductive layer prevents static electrification accumulation by providing a charge dissipation path without compromising the structural integrity or environmental resistance of the insulator material.
3Object-affected harmful factors
If conductive carbon-fiber reinforced plastic (CFRP) is used instead of insulator materials, then static electrification is suppressed, but the weight reduction and environmental resistance benefits of insulator materials are lost
Solution Approach 1:
The invention uses a composite structure combining insulator material (such as GFRP) with a conductive layer. This composite approach allows the insulator material to provide weight reduction and environmental resistance benefits, while the conductive layer suppresses static electrification. The combination of materials with different properties (insulating and conductive) resolves the contradiction by achieving both weight reduction and static electrification suppression simultaneously.
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 design effectively suppresses static electrification, reducing the risk of fuel ignition and allowing the capacitive level gauge to be safely used in aircraft fuel tanks by ensuring electric charges are dissipated, even when insulators are employed in the structural bodies.
Implementation Method 1
a streaming electrification phenomenon occurs between the fuel and the cylindrical structural bodies when the fuel flows
Implementation Method 2
measures the capacitance between the inner electrode and the outer electrode and detects the level of a measurement object
Implementation Method 3
an electrical double layer is formed therebetween, and electrification with a large amount of static electricity occurs on the surfaces of the cylindrical structural bodies opposite from the electrodes
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Provided is a fuel oil gauge (15), comprising: a columnar interior structural body (27) formed from an insulator; a hollow cylindrical exterior structural body (23) formed from an insulator, which is positioned on the exterior circumference side of the interior structural body (27) around the total perimeter thereof with a gap therebetween; an interior electrode (29) which is affixed to the exterior circumference face of the interior structural body (27); and an exterior electrode (25) which is affixed to the interior circumference face of the exterior structural body (23). The fuel oil gauge (15) measures capacitance between the interior electrode (29) and the exterior electrode (25), and detects the level of fuel present between the interior electrode (29) and the exterior electrode (25). The exterior structural body (23) further comprises a plurality of exterior side through holes (31) that allow electrical charge to move from the exterior circumference face thereof to the exterior electrode (25).