| 摘要 |
In order that a flow tube (3) of a Coriolis flowmeter (1) may be vibrated in the tertiary mode using one drive device (4), the drive device (4) is arranged at the antinode(H2) in the center of tertiary mode vibration, and vibration detecting sensors(5,5) are arranged at two antinodes (H1, H3) other than the antinode (H2) in the center of tertiary mode vibration. Furthermore, the displacement polarity of the drive device (4) is opposite to those of the vibration detecting sensors (5,5) so that the vibration phases of the flow tube (3) are in a relation of mutually opposite phases. Furthermore, in the positive feedback loop of the excitation circuit portion (9) for exciting tertiary mode vibration of the flow tube (3) and the vibration detecting sensors (5, 5), the excitation circuit portion (9) is structured so that the relation between the displacement polarities where the vibration phases of the flow tube (3) are opposite to one another is converted to the relation where the vibration phases of the flow tube (3) are in phase. |
