| 摘要 |
PURPOSE:To improve the measuring accuracy of an ultrasonic flowmeter, by eliminating ultrasonic waves caused by the influence of the vibration of a pipeline and detected by a oscillator from ultrasonic waves detected by a receiver. CONSTITUTION:An oscillator 6 is buried in an ultrasonic wave transmitting material 3 in a united condition in the same way as for a transmitter 1 and receiver 2 and its main receiving passage is formed with an air layer having high acoustic impedance, namely, an air hole 7. This ultrasonic flowmeter is installed to a pipeline 8 which transports a fluid with an acousting coupling material 9 in- between. The output signal of the receiver 2 is introduced to an arithmetic circuit through lead wires 11 and 12 so that the signal can be offset by the output signal of the vibrator 6 and only ultrasonic waves containing no oscillation component of the pipeline 8 are found. |
