Sensor for measuring the mass flow rate of a flowable medium

A vibronic measuring transducer for measuring mass flow of flowable medium, comprising:

• an oscillatable measuring tube configured to convey the medium therethrough, the measuring tube having an inlet side and an outlet side, wherein the measuring tube is bent in its rest position in a tube plane;
• a tube inlet section adjoining the inlet side of the measuring tube;
• a tube outlet section adjoining the outlet side of the measuring tube;
• at least one oscillation exciter configured to excite bending oscillations of the measuring tube in a bending oscillation use-mode;
• two oscillation sensors configured to register oscillations of the measuring tube;
• a support system including a support plate, an inlet-side securement body and an outlet-side securement body, the support system having support system oscillation modes comprising elastic deformations of the support plate;
• and
• a housing, wherein:
• the measuring tube is rigidly connected to the support plate via the inlet-side securement body and the outlet-side securement body and is bounded by the inlet-side and outlet-side securement bodies;
• the measuring tube is connectable to a pipeline via the tube inlet section and the tube outlet section;
• the tube inlet section and the tube outlet section are each connected rigidly with the housing;
• the support plate includes one or more spring securements, each spring securement formed in the support plate by at least one cut in the support plate;
• the support plate is resiliently secured relative to the housing via the one or more spring securements such that the support plate has three translation oscillation degrees of freedom and three rotation oscillation degrees of freedom;
• eigenfrequencies of oscillations of the support plate relative to the housing due to the translation oscillation degrees of freedom and the rotation oscillation degrees of freedom are lower than a use-mode eigenfrequency of the bending oscillation use-mode;
• the use-mode eigenfrequency is lower than the eigenfrequencies of the support system oscillation modes;
• the measuring tube has a substantially two-fold rotational symmetry relative to a symmetry axis extending perpendicularly to the tube plane;
• a calibration factor describes in first approximation a proportionality between a mass flow through the measuring tube and a phase difference between oscillations of the measuring tube oscillating in the bending oscillation use-mode at the sites of the two oscillation sensors
• the calibration factor in case of rotations of the measuring transducer about a rotational axis, which extends perpendicular to the symmetry axis and perpendicular to a longitudinal axis of the measuring transducer has an angular velocity dependence;
• the angular velocity dependence of the calibration factor depends on a respective position of each of the oscillation sensors;
• positions of the oscillation sensors exist for which the angular velocity dependence of the calibration factor has a minimum;
• and
• each oscillation sensor is positioned such that the angular velocity dependence of the calibration factor does not exceed the minimum by more than 20% of the minimum.