Coriolis mass flowmeter

A Coriolis mass flowmeter operated by deforming and vibrating a vibration tube through which a measuring fluid is passed, using a Coriolis force generated by the flow of the measuring fluid and the angular vibration of the vibration tube. In this mass flowmeter, the vibration tube is fixed to the housing at the upstream fixed point and downstream fixed point and the original axis is taken as a straight line connecting these fixed points. The vibration tube is operated so that the tube performs simple harmonic oscillation or circular motion on circumferences at predetermined distances away from each point of the original axis around the original axis taken as the center. Since the vibration tube oscillates only in the circumferential planes at equal distances from the original axis, the length of the vibration tube does not vary regardless of the position of the tube. Accordingly, the tensile force in the direction of the axis is always constant. That is, the leakage of vibration due to the variation in the force in the direction of the axis can be eliminated. Enhanced isolation of vibration makes vibration inside the flowmeter stable and this enables a highly accurate and stable Coriolis mass flowmeter to be achieved. Specifically, since the Q value of the internal vibration becomes high, a Coriolis mass flowmeter is achieved that is not easily affected by vibration noise, consumes less power, and reduces zero and span changes due to changes in the amount of vibration leakage.