| 摘要 |
PURPOSE:To obtain high-reliability data with low power consumption and to realize long-period use by detecting sing-around frequency by using ultrasonic-wave reflecting plates each between a couple of transmitter-receivers. CONSTITUTION:A main body 1, while disconnected from a reader 37, is placed in a fluid so that its supporting shaft 11 is nearly at a vertical angle. A supporting member 10 faces in a direction determined by a permanent magnet without reference to the direction of the main body 1, and transmitter-receivers 14N, 14S, 14E and 14W are positioned at the north, south, east, and west sides of the supporting shaft 11. According to a program stored in a storage part 26, a measurement part 20 performs measuring operation in every prescribed period through a power control part 30 in response to a command signal from a processor 25. In this case, reflecting plates 8 for ultrasonic waves each between a couple of transmitter-receivers invert the propagation direction of ultrasonic waves, couple by couple, to detect respective sing-around frequencies, thereby obtaining directly a digital signal regarding the velocity of the fluid regardless of the velocity of sound. |
