Abstract: An optical fluid level monitor is disclosed. It comprises a plurality of prismatic sensors disposed in a linear array for measuring the levels of fluids, such as oil, in sumps of aircraft and helicopter engines and other closed containers. In use each of the sensors is sequentially pulsed by an integral light source. If the detector is above the fluid level it appears bright, if below it appears bright, if below it appears dark, this difference being caused by an integral light detector device. Counting circuits are provided to determine the number of bright sensors and electronically convert this into a fluid volume for display purposes. A presettable low volume alarm is also included as is a correction circuit to compensate for volume changes caused by heating of the fluid in use.

Abstract: An electromagnetic system is provided to capture ferrous particles in a circulating fluid medium and provide analog and digital data which relate both to the mass of any significant individual particles captured and the total mass of such particles accumulated in a given time for subsequent retrieval. A periodic self checking capability is also included to determine if the system is functioning normally.

Abstract: A filler cap assembly for containers of liquids, particularly of those which require periodic replenishing, checking or replacement, such as for rotating machines, internal combustion engines and motors. The filler cap is locked in a vibration-proof manner in its closed position by means of a mechanical spring and bosses arranged exteriorly with respect to the filler neck and is tiltable about bosses on the filler neck into the open position remaining captive with the filler neck. Additional elements can be mounted on top of the filler cap for specific operational purposes.