| 摘要 |
PURPOSE:To correct the temperature of an output, by using output temperature correction constants, which are determined by the inside diameter of a pipe through which a fluid to be measured is flowed, the angle of incidence of ultrasonic propagation, and the acoustic velocity of ultrasonic waves, a fluid speed correction coefficient, and the ultrasonic propagation time, to obtain a flow rate of the fluid. CONSTITUTION:Ultrasonic wave transmitter and receivers 1a, 1b, 2a, and 2b are attached and fixed to a pipe 5, through which a fluid to be measured is flowed, through ultrasonic wave transmitter and receiver attaching members 3a, 3b, 4a, and 4b. The transmission and the reception of ultrasonic signals are controlled by a circuit part 6 to measure the time difference of ultrasonic propagation between the normal direction and the reverse direction and the ultrasonic propagation time from transmission to reception. Temperature compensation is performed by an output temperature compensating part 7. A flow rate Q of the fluid is obtained by equations (1) and (2). In equations, A and B are output temperature correction constants, and K, (d), theta, (c), (t) and DELTAt are the fluid speed correction coefficient, the inside diameter of the pipe, the angle of incidence of ultrasonic propagation, the acoustic velocity of ultrasonic waves, the ultrasonic propagation time, and the time difference of ultrasonic propagation respectively. |
