FIBER-OPTIC HEAT-LOSS ANEMOMETER Russian patent published in 1996 - IPC

FIELD: measurement technology; measurement of velocities in liquid currents in presence of hydroacoustic and hydrophysic interferences encountered, in particular, in oceans and seas. SUBSTANCE: fiber interferometer with heat-sensing element in its working side is built up of two fibers (working and reference ones). Heat-sensing element is heated by radiation heater through wavelength other than that of coherent light source of interferometer. Radiation heater rays are absorbed by heat-sensing element which raises its temperature, and radiation is filtered off by means of special optical filter mounted upstream of interferometer photodetector. Since working and reference fibers are placed in liquid current, fiber-optic flowmeter is very sensitive to current speed pulsations and also is immune to hydrophysical interference. Pulsatory interferences (including hydroacoustic ones) are eliminated by random folding of working and reference fibers into single coil. In this case, heat-sensing element is mounted on outer turn of coil and is heat-insulated from it. EFFECT: improved sensitivity to current flow speed, improved immunity to hydrophysical and hydroacoustic interferences. 5 cl, 3 dwg