PRESSURE DETECTOR AND CURRENT METER UTILIZING SAID DETECTOR

• Main Authors: SHICHIRI MASATAKA, KABEUCHI TERUO, MUKONO KATSUHIKO
• Format: Patent
• Language: English
• Published: 09.07.1990
• Subjects: MEASURING; MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL; METERING BY VOLUME; PHYSICS; TESTING

PURPOSE:To make it possible to measure the flow speed and the flowing direction simply and definitely even if fluid flows in a tightly closed pipe by projecting light on a thin film whose thickness is changed with applied pressure, and obtaining the pressure of the fluid based on the interference of the reflected lights from the front surface and the rear surface. CONSTITUTION:Monochromatic light which is introduced into an optical fiber 9 is projected on a dielectric thin film 5 whose thickness is changed with applied pressure through an optical glass 4. Part of the light is reflected from the front surface. The remaining light is reflected from the rear side interface, inputted into the glass 4 and propagated in the glass together with the reflected light from the front surface. The reflected light are inputted into an optical fiber 10 from the surface of the glass and guided into a photodetector. That is, the brightness of the surface of the thin film is determined by the intensity of the interference light of both reflected lights in consideration of phase difference. The thickness of the thin film is found from said intensity, and the pressure of fluid is obtained. In a current meter provided with two pressure detectors such as this, a detector 30 on the upstream side of a flow 40 detects the total pressure. A detector 31 on the downstream side detects the static pressure of the fluid. The dynamic pressure component is computed from the difference between both pressures, and the flow speed is obtained. The flowing direction is obtained by finding which detector outputs higher value.