Capacitive Sensor Purging Tool for Aircraft Fuel Tank Water Extraction
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Solution Overview
Problem
Existing methods for extracting water from aircraft fuel tanks are challenging due to difficulties in accessing bleed valves and relying on visual identification of water and fuel, which can be inaccurate and lead to fuel loss.
Innovation Solution
A purge tool equipped with a capacitive sensor and a computer system that determines the nature of the liquid flowing from the tank, using measurement signals to differentiate between water, fuel, and their mixtures, and generates alerts to indicate when only fuel is present, allowing for precise water extraction and minimizing fuel loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual identification method is used to differentiate water and fuel, then no additional equipment is needed, but the identification accuracy deteriorates leading to fuel loss
Solution Approach 1:
The patent replaces the manual visual identification method with an automated capacitive sensing system. The capacitive sensor detects dielectric properties of liquids to automatically distinguish between water and fuel, eliminating reliance on human visual judgment and preventing fuel loss due to inaccurate identification.
Solution Approach 2:
The patent introduces a capacitive sensor as an intermediary device between the liquid stream and the operator. This sensor acts as a mediator that translates physical properties of liquids (dielectric constant) into electrical signals, enabling accurate differentiation without direct visual contact and preventing fuel loss.
2Productivity
If drain valve is opened for water extraction, then water can be removed from tank, but fuel may be lost due to inability to precisely detect water-fuel boundary
Solution Approach 1:
The patent implements a feedback control system where the capacitive sensor continuously monitors the liquid composition during drainage and provides real-time signals to the control unit. When the sensor detects the transition from water to fuel, it triggers an automatic valve closure signal, enabling precise control of the extraction process and preventing fuel loss.
Solution Approach 2:
The system enables self-service operation where the capacitive sensor and control unit automatically detect liquid boundaries and control the drainage process without continuous operator intervention. The system serves itself by autonomously determining when to stop water extraction and prevent fuel loss.
3Ease of operation
If transparent tube is used for visual monitoring, then liquid color can be observed, but the monitoring reliability deteriorates when drain valve is difficult to access
Solution Approach 1:
The patent replaces the mechanical visual monitoring system with an electrical sensing system. The capacitive sensor provides electronic detection of liquid properties, which is more reliable than visual observation through a transparent tube, especially when the drain valve is in difficult-to-access locations.
Solution Approach 2:
The capacitive sensor serves as an intermediary that provides reliable indirect measurement of liquid composition. Instead of requiring direct visual contact with the liquid stream, the sensor mediates the detection process through electrical field interactions, ensuring reliable operation even when visual access is limited.
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
The tool accurately identifies the presence of fuel, enabling operators to stop the water extraction process, thus preventing fuel loss and ensuring efficient water removal from aircraft fuel tanks.
Implementation Method 1
Each capacitive sensor (40) emits a measurement signal which varies according to at least the nature of the liquid
Implementation Method 2
The electrical capacitance of the capacitor, and consequently the measurement signal emitted by the capacitive sensor, varies depending on the nature and/or height of the liquid passing through this magnetic field
Data Source
Figure 1~3
Figure 4~9
AI summary
The present invention relates to a purging tool (20) having a tube (25) delimiting an internal space (INT). The tube (25) has at least one capacitive sensor (40), said purging tool comprising a computer (50) connected to the capacitive sensor (40) and to at least one warning generator (60), said capacitive sensor (40) being configured to transmit a measurement signal to the computer (50), said computer (50) being configured to determine, using the measurement signal, whether a liquid flowing from the tank into said internal space (INT) is fuel, said computer (50) being configured to transmit a warning signal to the warning generator (60) at least when said liquid is fuel, said warning generator (60) being configured to generate a warning on command from the computer when said liquid is fuel.