| 摘要 |
PURPOSE:To increase the measurement accuracy for the ultrasonic flowmeter by providing plural number of ultrasonic elements to either or both of the ultrasonic wave transmitter and receiver and then giving scanning to these elements to vary virtually the distance between the wave transmitter and receiver. CONSTITUTION:Ultrasonic wave transmitter 12 composed by arranging ultrasonic elements 12a, 12b...12n is installed at one side part of waveguide 11, and at the same time ultrasonic wave receiver 13 is provided at the other side part of waveguide 11 opposing to transmitter 12 and at the side more downstream than the attachment position of transmitter 12. Then the ultrasonic wave of a certain frequency is transmitted to be received at receiver 13 while giving the sequential scanning to the ultrasonic elements of transmitter 12. In this case, the frequency change is decided by the scanning velocity and the speed of fluid 10. In this connection, if the scanning is given by deciding previously the scanning speed, a high-accuracy measurement is ensured for the speed of fluid 10 based on the reception frequency of receiver 13. |
