| 摘要 |
PURPOSE:To take a measurement irrelatively to whether there is a contaminant or not by arranging a receiving body having an array of plural receivers and a transmitting body opposite each other, and switching the respective receivers much faster than a flow velocity and transmitting and receiving a noisy signal. CONSTITUTION:A couple of the ultrasonic transmitting body 1 and receiving body 2 are arranged on the external surface of a tube 9 opposite each other at right angles to the flow. Then, the transmitting body 2 converts a high frequency signal outputted by an ultrasonic wave oscillator 3 into an ultrasonic wave, which is emitted into the fluid in the tube 9. This ultrasonic wave is received by the receiving body 2 after amplitude or phase modulation is imposed. Then, the respective receivers are switched much faster than the flow velocity to transmit and receive the noisy signal. Then, an arithmetic circuit 8 inputs data on the switching frequency f1 of a switching circuit 4 and a clock frequency f2 to calculate the flow velocity V from an equation and further multiply the flow velocity V by the sectional area of the fluid, calculating the flow rate. Consequently, the flow velocity and flow rate are measured irrelevant to whether there is a contaminant or not. |
