| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a tertiary mode oscillation type Coriolis flow meter capable of lightening vibration leakage and of being made to be cheap with a simple shape constitution. <P>SOLUTION: The coriolis flow meter 1 is constituted with: at least one flow tube 3; a driving device 4 for alternatively driving a flow tube 3 supported at its both ends having inlet and outlet ports; a pair of vibration sensors 5, 5 for detecting the phase difference proportional to the Coriolis force activating the flow tube 3. For making the flow tube 3 vibrate with the tertiary mode, the driving device 4 is placed at the position of a center antinode H2 among 3 antinodes H1-H3 to be generated by the tertiary mode vibration, and at the same time the vibration detection sensors 5, 5 are arranged at antinodes H1, H3, further, the displacement polarity of the driving device 4 and the displacement polarity of the vibration detection sensors 5, 5 are made in reverse phase relation, and at the same time an excitation circuit 9 is made to be mutually in phase on its positive feed back loop with each displacement polarity made to be in reverse phase. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
