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Schematic of Leak Detection

KBSI developed a sensor system, the Leak Inspection, Quantification and Detection System (LIQDS), for the Naval Air Warfare Center at Patuxent River that detects fluid leaks, pinpoints the leak location coordinates, identifies the type of fluid and quantifies the leakage rate.  This is achieved remotely without inserting a sensor at the location of leak. Such a system will be extremely useful for the new generation aircraft.

The effectiveness of a system is only as good as its weakest link and, hence, it is critical to improve subcomponent reliability. Current on-board health monitoring systems do not have the sensitivity to detect slow fluid leaks. This reduces confidence in the health status mandating scheduled manual inspections. This technology would allow early detection of fluid leaks thereby avoiding serious damage to subsystem components and improve the health of the system.

KBSI successfully developed algorithms to separate out individual fluid components from the signatures of a mixture of fluids. A drip rig was developed to simulate various fluids dripping and collecting to the central point, or, the weep hole. While our demonstration used capacitance technology sensors integrated into a trap design, the principles of the operation of our device allowed us to provide sensing around the weep hole as concentric ring of capacitive sensors. Finally we showed that differentiating water from the other fluids is easy due to the large difference in signature using our capacitance sensors.

We also demonstrated that IR Spectroscopic techniques can identify individual fluids and differentiate the components of a mixture of fluids. Three different sensors from three different vendors have been used in our experiments. In spite of the differences in signatures, we demonstrated our initial algorithms work with each sensor type for the purpose of leak detection. Next, we developed a capacitance based LIQDS technique that can identify individual fluids and in addition can quantify the leak volume. KBSI developed a computerized drip rig to test the mixing of different fluids and used it to test the developed capacitance technique.

Remote leak detection is critical for applications in modern aircraft industry and also in process plants and other fluid transportation industry. In-situ sensors and wiring could reduce overall system reliability and hence a remote monitoring system has good potential in future health monitoring and condition based maintenance systems.