Abstract: An arrangement for sensing temperature changes at an object, specifically within a transformer or the like, is disclosed herein. In one embodiment, this arrangement utilizes as one of its main components a sensor including a solid glass medium which changes in optical density with changes in temperature, a single optical fiber for directing a beam of light into the glass media, a single optical fiber for collecting the light transmitted through the medium, and an optical means for imaging the transmitted light to the collecting fiber. In addition, in this embodiment, the light is caused to pass through the glass medium such that the amount of light reaching the collecting fiber is linearly dependent upon the temperature at the medium with respect to temperatures within a wide range.

Abstract: A particle size analyzer that measures the intensity of light scattered by moving particles passing through the probe of a crossed beam laser anemometer, verifies that the measured signal was produced by a particle passing through a region near the center of the probe, and stores count values related to the number of particles producing the same scattered light intensity value is disclosed. Since scattered light intensity values are related to particle size, the stored count values equal the number of particles of the same size detected by the analyzer. In the preferred form of the invention, the measured light intensity determines the address of a particular intensity bin of a storage system. After verification to determine if a measured intensity value was produced by a particle passing through a region near the center of the probe, the count value stored in an intensity bin related to the measured value is updated by one.

Abstract: A gauge for measuring small changes in the contour of the surface of a moving part, such as a rotating cylinder or sliding flat surface, as the part passes a point, using a monochromatic source of coherent light is disclosed. The gauge is based on the fact that the size and rate of movement of the speckles of a speckle pattern (formed by coherent light focused onto a nonspecular moving surface) vary in accordance with whether or not the beam is actually focused on the surface. In the preferred form of the present invention, an expanded and collimated laser beam is focused by a focusing lens onto the surface of the moving part. The speckle pattern light reflected by the moving surface is received by one or more photodetectors. The photodetectors develop pulses at a rate determined by the rate of speckle movement. These pulses are applied to a signal processor that counts them, if they are above a predetermined level.