| 摘要 |
PURPOSE:To detect variation in stress due to a Karman vortex street sensitively with simple structure by providing a duct in which fluid to be measured runs, a columnar vortex generation body which is inserted at right angles to the duct, and a strain detection part. CONSTITUTION:An alternating force operates on the vortex generation body 2 in which fluid flows in the duct 1 by Karman vortex street as shown by an arrow X and stress variation in the opposite direction occurs in the section of the vortex generation body 2 across the center axis. Strain variation corresponding to this stress variation is transmitted to the flank of the long groove 5 of a collar part 3 and detected by piezoelectric elements 6A and 6B. The element 6A and 6B are stuck on the flank of the long groove 5 of the collar part 3, so they are united substantially with the vortex generation body 2 and strain is detected where the variation is large. The element 6A and 6B output an electric signal corresponding to the strain variation of the vortex generation body 2 and number of changes of this electric signal is detected to detect the frequency of vortex generation, thereby measuring the flow velocity and rate of the to be measured fluid flowing in the duct 1 with good sensitivity.
|
