| 摘要 |
PURPOSE:To obtain an ultrasonic flow meter detecting the optimum frequency and optimum fitting positions of ultrasonic wave transmitters/receivers, by fitting a pair of ultrasonic wave transmitters/receivers to the external wall of a pipe in which fluid to be measured flows and detecting an envelope of a received signal. CONSTITUTION:Ultrasonic wave transmitters/receivers 11a, 11b are fitted to the external wall 3 of a pipe in which fluid 2 to be measured flows and an output from the ultrasonic wave transmitter/receiver 11b is inputted to a CPU 8 through an amplifier 12 and a differential circuit 13. The CPU 8 detects the increment or reduction of the envelope of a signal received from the differential circuit 13 and selects the frequency of an ultrasonic wave pulse so as to be coincident with the resonance frequency of the pipe wall 3 to change the frequency generated from the ultrasonic wave transmitter/receiver 11a. In addition, the CPU 8 discriminates whether these ultrasonic wave transmitters/receivers are set up on their optimum fitting positions from the disturbance of the waveform of envelope of the received signal and displays the discriminated result on a display device. Consequently the optimum frequency and optimum fitting positions of the ultrasonic wave transmitters/receivers can be detected. |
