| 摘要 |
PURPOSE:To allow an oscillator to possess together both characteristics of a wide frequency band area and high sensitivity by changing the shape of the oscillator which converts alternately an electric oscillation and an ultrasonic wave to the shape having thickness of integer-fold of 1/2 of the wave-length of a switched ultrasonic wave and outputting simultaneously a frequency component having each thickness. CONSTITUTION:The thickness of the oscillator 1 is shaped to be changed in order to different thickness of the integer-fold of 1/2 wave-length that is formed like a step at its back face and the back face is held with a damper 2 that is made of a material such as bakelite, epoxy resin, etc. A contact plug 4 and the oscillator 1 which are mounted at one end part of a metalic case 3 are connected electrically through an electrode 5 mounted on the back face of the oscillator 1 and the oscillator 1 and the case 3 are connected electrically through an electrode 6. When an electric pulse is given to the oscillator 1 from an ultrasonic flow inspector through the contact plug, at the oscillator 1, different resonating states are created according to different thickness of step-shape and simultaneously ultrasonic waves having frequency components corresponded with the resonance and a wide frequency band area is generated. On the other hand, the high sensitivity is maintained as it is by leaving the performance of the damper to be a low damping.
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