Optical position sensor for determining the interface between a clear and an opaque fluid

United States Patent

May 23, 2006
View the Complete Patent at the US Patent & Trademark Office
Fluid Interface Position Optical Sensor
An inexpensive, optical position sensor for measuring a position or length, x, along a one-dimensional curvilinear, coordinate system. The sensor can be used, for example, to determine the position of an interface between a clear and an opaque fluid (such as crude oil and water). In one embodiment, the sensor utilizes the principle of dual-fluorescence, where a primary fiber emits primary fluorescent light and a parallel secondary fiber collects a portion of the primary fluorescent light that is not blocked by the opaque fluid. This, in turn, excites secondary fluorescence in the secondary fiber at a longer wavelength. A light detector measures the intensity of secondary fluorescence emitted from an end of the secondary fiber, which is used to calculate the unknown position or length, x. Side-emitting fibers can be used in place of, or in addition to, fluorescent fibers. The all-optical sensor is attractive for applications involving flammable liquids.
Weiss; Jonathan D. (Albuquerque, NM)
Sandia Corporation (Albuquerque, NM)
December 21, 2004
250/577 ; 250/573; 250/574; 250/900; 250/904; 340/619; 73/290R; 73/293; 73/64.55;
G01N 21/49 (20060101);
250/573-577,900,904 340/619,686.1 73/64.55,293,290B,290R 385/12,141,142
FEDERALLY SPONSORED RESEARCH The United States Government has rights in this invention pursuant to Department of Energy Contract No. DE-AC04-94AL85000 with Sandia Corporation.