| 摘要 |
PURPOSE:To measure the quantity of a high-temperature fluid, by providing a detector which detects the oscillation stress, which is generated in a vortex generating material formed with a part of an optical fiber, as a change of the intensity of light between photodetectors attached to both ends of the optical fiber. CONSTITUTION:The optical fiber is inserted through a duct 11 in parallel with the section of the duct 11, and a vortex generating material 5 is formed in a fluid 12. A light emitting element 8 and a photodetector 9 are attached to both ends of optical fibers 6 and 7, and an electric controlling part 10 is provided which supplies a driving electric power to the element 8 and receives an electric signal from the detector 9 to perform the signal processing. In this constitution, the intensity of passing light is changed in the generating material 5 by the alternating differential pressure due to Karman vortex streets 13 and 14 generated at the rear of the generating material 5. This change is detected by the detector 9, and an alternating vortex generation frequency is obtained in the controlling part 10, thereby obtaining the speed of the fluid 12 proportional to this frequency, namely, the flow rate of the fluid 12. Optical fibers are strong against a high temperature and are not affected by the electromagnetic field. |
