| 摘要 |
PURPOSE:To improve an S/N ratio of a vortex flow meter, by a method wherein two inverted polarization type piezo-electric sensors are located at a given distance in a sensor part, and the influence of a noise due to a disturbance vibration is eliminated through computation of a sensor output. CONSTITUTION:A cylindrical nozzle 12 is positioned at a right angle to a line 11 through which measuring fluid in a vortex discharge detector 10 flows, and a vortex generating body 13 is inserted through a nozzle 12 at a right angle to the line 11. Two inverted polarization type piezo-electric sensors 14a and 14b are fastened by press at a given distance in a concavity 13d in the vortex generating body 13. The sensors 14a and 14b are formed such that electrodes, separated to the right and left facing a flow direction of measuring fluid, are symmetrically mounted to the surface and the back of a piezo-electric element on a disc positioned so that its center coincides with the neutral axis of the vortex generating body 13, a charge in a reverse direction is generated between the two electrodes against a stress in a bending direction, and a charge due to a stress in a flow direction of fluid is cancelled. |
