The present disclosure relates to a mass flow meter according to the Coriolis principle, comprising two measuring tube pairs which have different usage mode natural frequencies, an exciter for exciting flexural vibrations and a vibration sensor pair for detecting flexural vibrations; and comprising a circuit for driving the exciters and for detecting signals of the vibration sensors, for determining flow-dependent phase differences between the signals of the inlet-side and outlet-side vibration sensors and for determining mass flow measurement values based on the flow-dependent phase differences, wherein the circuit is configured to perform, when determining the mass flow measurement values based on the flow-dependent phase differences, a zero-point correction for the first measuring tube pair and/or the second measuring tube pair using signal amplitude ratios of the measuring tube pairs.

The Coriolis flowmeter according to the present disclosure includes: a measuring sensor including a bent measuring tube mirror-symmetrical with respect to a transverse plane, wherein a measuring tube center line runs in a longitudinal plane oriented perpendicular to the transverse plane, wherein an equatorial surface runs perpendicular to the longitudinal plane along the measuring tube center line; an exciter for exciting measuring tube bending vibrations; a first pair of vibration sensors for capturing the bending vibrations of the measuring tube; and an operating and evaluation circuit for driving the exciter, for capturing signals from the vibration sensors, and for determining a mass flow measured value, wherein the measuring sensor has a second pair of vibration sensors, which are arranged in a mirror-symmetrical manner with respect to the transverse plane, wherein the first pair of vibration sensors is separated from the second pair of vibration sensors by the equatorial surface.

Methods for operating a flowmeter diagnostic tool are provided that comprise interfacing the diagnostic tool with a flowmeter (5) sensor assembly (10). A base prover volume (BPV), a desired number of passes per run, and/or a maximum number of allowed runs may be input into the diagnostic tool. Flowmeter data is received. An estimated total prove time (TPT) necessary to pass a predetermined repeatability requirement, an estimated minimum number of runs needed to achieve the calculated TPT, and/or an estimated minimum BPV may be calculated. A standard deviation of the flowmeter sensor assembly flow rate () is calculated, and the number of samples used to calculate a is determined. A meter-specific factor (MSF) is calculated.

A system (600, 700) for correcting a measured flow rate for viscosity effects of a fluid in a vibratory meter (5) is provided. The system (600, 700) includes a sensor assembly (10) and a meter electronics (20) communicatively coupled to the sensor assembly (10). The meter electronics (20) is configured to receive sensor signals from the sensor assembly (10), determine a non-viscosity correlation parameter based on the sensor signals, and correlate the non-viscosity correlation parameter to a viscosity of a fluid in the sensor assembly (10).

A multichannel flow tube (300) for a vibratory meter (5), and a method of manufacturing the multichannel flow tube are provided. The multichannel flow tube comprises a tube perimeter wall (304), a first channel division (302b), and a first support structure (308a). The first channel division is enclosed within and coupled to the tube perimeter wall, forming a first channel (306b) and a second channel (306c). The first support structure is coupled to the tube perimeter wall and the first channel division.

A method of determining a zero offset of a vibratory meter at a process condition is provided. The method includes measuring a flow rate of a material in the vibratory meter, determining if the measured flow rate is less than a low flow threshold, measuring one or more operational parameters of the vibratory meter, determining if the one or more measured operational parameters of the vibratory meter are within a corresponding range, and if the measured flow rate is less than the low flow threshold and if the one or more measured operational parameters of the vibratory meter are within the corresponding range, then determining a zero offset of the vibratory meter based on the measured flow rate.

Vibratory meters (5), and methods for their use measuring a fluid are provided. Each vibratory meter includes a multichannel flow tube (300) comprising two or more fluid channels (302), a pickoff (170), a driver (180), and meter electronics (20) configured to apply a drive signal to the driver at a drive frequency, and measure a deflection of the multichannel flow tube with the pickoff. In examples, at least one fluid channel has an effective diameter that is related to kinematic viscosity, inverse Stokes number, and drive frequency; velocity of sound and drive velocity; or the length of the flow tube. In further examples, the driver may apply a drive signal to the driver having a drive frequency proportional to the kinematic viscosity, inverse Stokes number, and effective diameter; or velocity of sound and effective diameter.

A vibratory meter (5) including a multi-channel flow tube (130) is provided. The vibratory meter (5) includes a meter electronics (20) and a meter assembly (10) communicatively coupled to the meter electronics (20). The meter assembly (10) includes the multi-channel flow tube (130, 330, 430, 530) comprising two or more fluid channels (132, 332, 432, 532) surrounded by a tube wall (134, 334, 434, 534). The two or more fluid channels (132, 332, 432, 532) and tube wall (134, 334, 434, 534) comprise a single integral structure. A driver (180) is coupled to the multi-channel flow tube (130, 330, 430, 530). The driver (180) is configured to vibrate the multi-channel flow tube (130, 330, 430, 530). The two or more fluid channels (132, 332, 432, 532) and tube wall (134, 334, 434, 534) are configured to deform in the same direction as the single integral structure in response to a drive signal applied to the driver (180).

A method for determining density and/or mass flow of a compressible medium with a measuring transducer of vibration-type having at least two oscillators, each including a pair of measuring tubes, wherein the pairs of measuring tubes are arranged for parallel flow, wherein the two oscillators have mutually independent oscillator oscillations with mutually differing eigenfrequencies for corresponding oscillation modes. The method includes steps of determining the values of the eigenfrequencies of at least two different oscillator oscillations, determining at least two preliminary density measured values based on the values of the eigenfrequencies, and determining a correction term for one of the preliminary density measured values and/or for a preliminary measured value of flow based on the preliminary density measured values and the values of the eigenfrequencies.

A method serves for operating a measuring transducer of vibration-type having at least two oscillators, each of which is formed by a pair of measuring tubes, wherein the pairs of measuring tubes are arranged for parallel flow, wherein the two oscillators have mutually independent oscillator oscillations with mutually differing eigenfrequencies for corresponding oscillation modes. The method includes steps of determining a first value of a primary measurement variable, or of a variable derived therefrom, using the first oscillator, determining a second value of the primary measurement variable, or of a variable derived therefrom, using the second oscillator, checking an actual ratio between the first value and the second value by comparison with an expected ratio between the first value and the second value, and outputting a signal when the actual ratio does not correspond to the expected ratio.