Abstract: An oxygen analysis system (OAS) for measuring, monitoring and recording oxygen concentration in aircraft fuel tanks. The OAS has a rack support structure installed in an aircraft cabin with a plurality of oxygen analyzer devices mounted in the rack support structure. Each oxygen analyzer device has an oxygen sensor to measure oxygen concentration in gas samples continuously drawn from sample locations in aircraft fuel tanks and at an aircraft NGS ASM exit. The OAS further has a plurality of valves, a supply of calibration gases, a supply of purge and operating gases, and a power distribution assembly, all coupled to the rack support structure. The OAS further has a transport tubing assembly, a plurality of fuel tank gas sampling ports, an NGS ASM exit gas sampling port, a drain manifold assembly, and a data acquisition and recording system having a user interface software to monitor and control the OAS.

Abstract: An oxygen analysis system (OAS) for measuring, monitoring and recording oxygen concentration in aircraft fuel tanks. The OAS has a rack support structure installed in an aircraft cabin with a plurality of oxygen analyzer devices mounted in the rack support structure. Each oxygen analyzer device has an oxygen sensor to measure oxygen concentration in gas samples continuously drawn from sample locations in aircraft fuel tanks and at an aircraft NGS ASM exit. The OAS further has a plurality of valves, a supply of calibration gases, a supply of purge and operating gases, and a power distribution assembly, all coupled to the rack support structure. The OAS further has a transport tubing assembly, a plurality of fuel tank gas sampling ports, an NGS ASM exit gas sampling port, a drain manifold assembly, and a data acquisition and recording system having a user interface software to monitor and control the OAS.

Abstract: A spectroscopy device comprises a laser diode/lens assembly driven by a periodic stepped laser diode drive current. Each period of the stepped laser diode drive current has a plurality of constant current intervals: a left baseline interval, a left skirt interval, a peak interval, a right skirt interval, and a right baseline interval. The left and right skirt constant current intervals are used to lock the laser radiation emitted during the peak interval onto a preselected absorption line. The left and right skirt intervals are also used to obtain a value indicative of line width. The peak interval is used to obtain a value indicative of peak absorbance. Multiplying the peak and line width values together yields a value indicative of a gas concentration which is substantially independent of foreign gas line-broadening effects.

Abstract: A spectroscopy device comprises a laser diode/lens assembly driven by a periodic stepped laser diode drive current. Each period of the stepped laser diode drive current has a plurality of constant current intervals: a left baseline interval, a left skirt interval, a peak interval, a right skirt interval, and a right baseline interval. The left and right skirt constant current intervals are used to lock the laser radiation emitted from the laser diode onto a preselected absorption line. The left and right baseline constant current intervals are used to subtract baseline absorption measurements from peak constant current interval absorption measurements. A high frequency common mode noise rejection circuit rejects noise common to a monitor radiation detector and a radiation detector which detects radiation passing through a sample cell. A serial line locking cell is provided to allow locking when little or no absorbing material is present in the sample cell.

Abstract: An electrical indicator is disclosed of the type including a housing with an elongated window therein, and an elongated scale and an adjacent, relatively-translatable index carried on an elongated tape loop, both viewable through the window. The indicator provides increased resolution over such indicators known to the prior art by placing the elongated scale also on a tape which is made translatable past the window but in a direction opposite to that of the tape carrying the index. Both tapes are driven by the same drum forming part of a DC torque motor, but are taken off a peripheral surface of that drum in opposite directions to achieve opposite translations of the tapes past the window. An electrical circuit for controlling the DC torque motor is disclosed, as are details of the DC torque motor and associated components of the electrical indicator.

Abstract: The required frequency of inspection, servicing and overhauling of jet engines is to a large extent determined by the history of excessive or over-temperature conditions of each engine. In order to monitor and record each such over-temperature condition, an indicator device is provided having electronic circuitry for processing a temperature signal from the jet engine and a light emitting diode matrix for graphically displaying each over-temperature incident. When the jet engine temperature exceeds a threshold over-temperature point, this occurrence is sensed and the circuitry of the indicator functions to automatically store and visually display the engine temperature as a function of time for the succeeding several seconds after the over-temperature condition has commenced.