Ellipsoidal reflectors have been proposed as collecting horns for ultrasonic leak detectors. Exploiting the classical focusing characteristics of ellipsoids, these reflectors would facilitate and enhance the detection of leaks in situations in which it is possible to bring leak-detecting sensors to within distances of the order of centimeters from leaks, but not closer. Leak detectors based on this concept could complement commercially available ultrasonic leak detectors equipped with paraboloidal reflectors for focusing over much longer distances. In a typical application, an ultrasonic receiving transducer would be positioned at one of the two foci of an ellipsoidal reflector. At the end opposite the transducer, the reflector would be truncated to provide an opening for the entry of sound and for positioning the reflector near a leak. When the reflector-and-transducer assembly was positioned to make the leak (or, for that matter, any other small source of ultrasound) lie at the other focus of the ellipsoid, the maximum amount of radiated ultrasound would be focused onto the transducer, resulting in maximum detector response. The principle of operation has been verified in experiments.

This work was done by Robert C. Youngquist and Robert Cox of Dynacs Engineering Co. Inc. for Kennedy Space Center.

NASA Tech Briefs Magazine

This article first appeared in the October, 2002 issue of NASA Tech Briefs Magazine.

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