Patent ID: 6782764
Filing Date: 2004-08-31
Classification: G01F

Abstract:
A Coriolis mass flowmeter, comprising:a vibration tube through which a fluid to be measured flows so that the flow of the fluid in cooperation with angular vibration of said vibration tube generates Coriolis force which causes vibratory deformation of said vibration tube; wherein said vibration tube has a curved configuration which is point symmetry with respect to the median point between an upstream fixed end and a downstream fixed end of said vibration tube and which has three inflection points, and performs, while maintaining the point symmetrical curved configuration, simple harmonic oscillation such that each point on said vibration tube oscillates on an arc of a predetermined radius from a reference axis which is a straight line interconnecting said upstream fixed end and said downstream fixed end of said vibration tube; and further comprising: an upstream oscillator and a downstream oscillator which are provided on said vibration tube; an upstream compensation vibrator extending along said reference axis, said upstream compensation vibrator having one end fixed to said upstream oscillator so as to receive from said upstream oscillator a torsional force which acts around said reference axis in the phase inverse to that of the torsional force acting on said vibration tube, the other end of said upstream compensation vibrator being fixed to a portion of said vibration tube near said upstream fixed end so that the torsional force of the inverse phase and the torsional force on said vibration tube cancel each other at the fixed other end of said upstream compensation vibrator; and a downstream compensation vibrator extending along said reference axis, said down stream compensation vibrator having one end fixed to said downstream oscillator so as to receive from said downstream oscillator a torsional force which acts around said reference axis in the phase inverse to that of the torsional force acting on said vibration tube, the other end of said downstream compensation vibrator being fixed to a portion of said vibration tube near said downstream fixed end so that the torsional force of the inverse phase and the torsional force on said vibration tube cancel each other at the fixed other end of said downstream compensation vibrator.