| 摘要 |
PURPOSE:To obtain a vortex flow meter of high detecting sensitivity, having a simple structure, by employing such constitution that a light source and a light-receiving part are disposed in the recess provided at one end of a vortex generating body, and the change in the quantity of light reflected from the bottom surface of the recess is detected. CONSTITUTION:When a fluid flows through a duct 1, Karman vortexes are alternately and regularly generated from both sides of a vortex generating body 2, so that the bottom surface 51 of a recess 5 in the vortex generating body receives a lifting power alternately changing in direction. As a result, there are changes in the quantity of light which goes out from a light-feeding fiber 60 and is incident on light-receiving fibers 61 and 62 after being reflected from the bottom surface 51. Said optical signals are inputted through light-receiving elements 91 and 92 and amplifiers A1 and A2 to an amplifier A3, from which the differential output between both signals is obtained. In addition, both signals are added to each other in an amplifier A4, and the light output of a light source 8 is controlled so that said added signal becomes a constant value with respect to a reference setting signal ES. Thereby, a vortex flow meter having both a simple structure and a high detecting sensitivity can be obtained. |
