| 摘要 |
PROBLEM TO BE SOLVED: To sense the flow velocity of a liquid which flows in a tube. SOLUTION: When an input electric signal is applied to a interdigital electrode 2 for input, leakage elastic waves are excited in a piezoelectric substrate 1. The waves are incident into the tube as first and second longitudinal waves via a part of the wall of the tube, they are reflected by two parts on the opposite side of the part of the wall of the tube, and they are detected as first and second electric signals by a first interdigital electrode 3 for output and a second interdigital electrode 4 for output. The flow velocity and the direction of the fluid inside the tube are sensed by a signal analytical means 5 as the difference between the first delay electric signal and the second delay electric signal. |
