Background: The failure mode of the bearings in aircraft gas turbine engines, or the gears in helicopter gearboxes, is usually metal fatigue. At the onset of failure, tiny metal flakes or chips are produced which are carried away by the lubricating oil. The ability to detect these chips while the aircraft is in flight gives several hours' warning, enabling the aircraft to be routed to a scheduled maintenance facility for repair.

Project: Product Resources engineers invented an entirely new and revolutionary way of sensing and measuring the size of metal chips entrained in the oil return lines of engines and gearboxes. Prototypes of the Product Resources invention are being used by NASA to instrument a gearbox test facility and are under evaluation by a major US engine manufacturer for incorporation into its latest engine design. The sensor head is designed to operate while immersed in 400 degree F oil. It can detect chips in a flow rate of up to 20 gallons/minute. Comprehensive operating software analyzes the output of the sensor to verify the characteristic signal generated by a chip and eliminate false signals. The size of each chip is measured and the rate of chip generation calculated. Alarms are preset to signal if the chip generation rate or chip size limits have been exceeded.

Technologies: electromagnetic induction, analog signal processing, microprocessor signal analysis, precision coil winding, digital logic, data logging, oil-tight enclosures, MIL spec. and aircraft industry quality standards, severe operating environments

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