Hughes Aircraft Company

Keith V Pearson

David B Chang

Victor Vali

Jackie R Webster

Norton L Moise

Albert F Lawrence

An ion drag air flow meter (10) including a gas ionizer (16), an ion collector (14) and apparatus (30) for converting the collected ions into a signal providing an indication of the flow of a gas (40).

Ion drag air flow meter

An evanescent wave liquid level sensor for measuring the density-compensated level of a liquid in a container. The sensor employs an eccentric core optical fiber fully immersed in the liquid to be measured. Light is injected into one end of the fiber. Some of the light will be lost due to evanescent wave losses. Changes in the ratio of the intensity of the input light and the reflected light are due solely to changes in the density of the liquid. Changes in the liquid density can then be used to compensate a liquid level measurement. Since the liquid temperature is related to its density, the sensor can also be used to measure changes in the liquid temperature.

Evanescent wave liquid level sensor with density compensation

A system for detecting the presence of known materials in a body or container. The system incorporates a gamma or X-ray source for irradiating the body with gamma rays to produce X-ray fluorescence of materials contained therein. A directionally discriminate X-ray detector is positioned to intercept X-rays emitted from the body and is adapted to pass only those X-rays having a predetermined wavelength and incident from a specific direction that are characteristic of a material of interest contained in the body. The detector includes a dislocation free single crystal having substantially parallel input and output surfaces. A second crystal aligned parallel to the first crystal may be disposed at a position offset from the first crystal to receive the X-rays transmitted by the first crystal in order to discriminate between materials fluorescing within the body. In a specific embodiment of the invention, the first detector comprises an elongated crystal which pass X-rays in accordance with the Borrmann effect. A plurality of the crystals are arranged in a linear array and the container is either scanned with the array or the container passed linearly past the array. The detected X-rays are measured in intensity and the data is processed by suitable data processor to generate a video image indicative of the presence and shape of the specific materials for which the system is adapted. In yet another specific embodiment of the invention, a plurality of such arrays can be arranged with the input surfaces of the crystals disposed at different Bragg angles to simultaneously detect the presence of a selected group of materials.

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Long Beach, CA, United States of America

Keith V Pearson