| 摘要 |
PURPOSE:To obtain a highly reliable representative flow velocity by providing a flow velocity detector for every plane of a plurality of parallel measuring planes in the flowing direction, and repeatedly computing the arithmetic mean of the local flow velocities expressed by the detected signals at the same time. CONSTITUTION:Ultrasonic flow velocity detectors 2 wherein ultrasonic transducers 4a and 4b are arranged in the facing patterned are provided on measuring lines 61-63. Detected analog signals 7al-7a3 expressing the local flow velocities are inputted into A/D converters 16-18, and signals 16a-18a are always outputted. When a control signal 15a is inputted, the converters 16-18 update the signal patterns of the signals 16a-18a. When a control signal 15b is further inputted, an arithmetic-mean operator 19 computes the arithmetic mean by using the signals 16a-18a and outputs a measured signal 19a. The signal is repeatedly outputted at a specified period based on the control signals 15a and 15b of a control part 15. Since the measuring lines 61-63 are provided in a measuring region 13 and the arithmetic mean is obtained based on the local flow velocities obtained at the same time in this way, the representative flow velocity of liquid 11 can be measured in high reliability. |
