Vibrating flow meter and method and diagnostic method for meter verification

Abstract

A vibrating flow meter (5) for meter verification is provided, the vibrating flow meter (5) comprising a meter electronics (20) coupled to a first pickoff sensor and a second pickoff sensor (170L, 170R) and coupled to a driver (180), wherein in an embodiment the meter electronics (20) is configured to: vibrate a flow meter assembly (10) in a single mode using the driver (180), determine a single mode current (230) of the driver (180) and determine first and second response voltages (231) generated by the first and second pickoff sensors (170L, 170R), respectively, calculate a frequency response function for the determined first and second response voltages (231) based on the determined single mode current (230), fit the generated frequency response function to a pole residual model, and verify proper operation of the vibrating flow meter (5) using a meter stiffness value (216), a residual deflection (218), and a meter mass (240).

Description

[0001] This application is a divisional application, and the invention name of the parent case is "Vibratory flow meter and method and diagnostic method for meter verification", the application date is December 19, 2014, and the application number is 201480073892.6. Technical Field

[0002] The present invention relates to meter electronics and, more particularly, to methods and diagnostics for meter verification in vibrating flow meters. Background Art

[0003] Vibrating conduit sensors, such as Coriolis mass flow meters or vibrating tube densitometers, typically operate by detecting the motion of a vibrating conduit containing a flowing material. Properties associated with the material in the conduit, such as mass flow, density, etc., can be determined by processing measurement signals received from a motion transducer associated with the conduit. The vibration modes of a vibrating material-filled system are generally affected by the combined mass, stiffness, and damping characteristics of the containing conduit and the material contained therein.

[0004] The conduit of a vibrating flow meter may include one or more flow tubes. The flow tubes are forced to vibrate at a resonant frequency, where the resonant frequency of the tubes is proportional to the density of the fluid in the flow tubes. Sensors located on the inlet and outlet portions of the tubes measure the relative vibration between the ends of the tubes. During flow, the vibrating tubes and the flowing mass are coupled together by Coriolis forces, causing a phase shift in the vibration between the ends of the tubes. The phase shift is proportional to the mass flow.

[0005] A typical Coriolis mass flow meter includes one or more pipes that are connected inline in a pipeline or other conveying system and convey materials (e.g., fluids, slurries, etc.) in the system. Each pipe can be considered to have a set of natural vibration modes, including, for example, simple bending, torsion, radial, and coupled modes. In a typical Coriolis mass flow measurement application, the pipe is excited with one or more vibration modes when the material flows through the pipe, and the movement of the pipe is measured at points spaced apart along the pipe. Excitation is typically provided by an actuator (e.g., an electromechanical device, such as a voice coil type drive) that disturbs the pipe in a periodic manner. The mass flow rate can be determined by measuring the time delay or phase difference between the movements at the transducer position. Typically, two such transducers (or pick-up sensors) are used to measure the vibration response of one or more flow pipes, and they are typically located at positions upstream and downstream of the actuator. The two pick-up sensors are connected to an electronic instrument via a cable connection. The instrument receives signals from the two pick-up sensors and processes the signals to derive mass flow rate measurements.

[0006] The phase difference between the two sensor signals is related to the mass flow rate of the material flowing through one or more flow tubes. The mass flow rate of the material is proportional to the time delay between the two sensor signals and can therefore be determined by multiplying the time delay by a flow calibration factor (FCF), where the time delay includes the phase difference divided by the frequency. The FCF reflects the material properties and the cross-sectional properties of the flow tubes. In the prior art, the FCF is determined by a calibration process before the flow meter is installed in a pipeline or other conduit. In the calibration process, the fluid is passed through the flow tube at a given flow rate and a proportionality constant (FCF) between the phase difference or time delay and the flow rate is calculated.

[0007] One advantage of a Coriolis mass flow meter is that the accuracy of the measured mass flow rate is not affected by the wear of moving parts in the flow meter. The flow rate is determined by multiplying the phase difference or time delay between two points on the flow tube by a flow calibration factor. The only input is a sinusoidal signal from a sensor that indicates the oscillation of the two points on the flow tube. The phase difference is calculated from these sinusoidal signals. There are no moving parts in a vibrating flow tube. Therefore, the measurements of phase difference and flow calibration factor are not affected by the wear of moving parts in the flow meter.

[0008] The problem is that flow tubes change over time, where the initial factory calibration may change over time as the flow tubes corrode, erode, or otherwise change. Thus, the flow tube stiffness may change from the initial representative stiffness value (or the original measured stiffness value) during the life of the vibrating flow meter.

[0009] The mass flow rate measurement can be generated according to the following equation ( ):

[0010] (1).

[0011] ( The term ) includes operationally derived (ie, measured) time delay values ​​(including the time delays present between the pickoff sensor signals), such as in this case the time delays due to the Coriolis effect related to the mass flow rate through the vibrating flow meter 5. Measured ( ) item ultimately determines the mass flow rate of the flowing material when the flowing material flows through the vibrating flow meter 5. ) term includes the time delay at zero flow calibration constant. Usually determined at the factory ( ) item and programmed into the vibrating flow meter 5. The time delay at zero flow ( The (FCF) term will not change, even if the flow conditions are changing. The FCF term is proportional to the stiffness of the flow meter. The (FCF) term includes the flow calibration factor and typically includes the geometric constant (G), Young's modulus (E), and moment of inertia (I), where:

[0012] FCF = G*E*I (2).

[0013] The geometric constant (G) for a vibrating flow meter is fixed and does not change. The Young's modulus constant (E) also does not change. In contrast, the moment of inertia (I) is the FCF component that may change.

[0014] Coriolis mass flowmeters have received great success in a variety of industries. However, Coriolis flowmeters, along with most other flowmeters, may suffer from the accumulation of deposits left by process fluids. This accumulation is generally referred to as a "coating" in the art. Depending on the characteristics of the process fluid, the fluid coating may or may not affect the performance and accuracy of the flowmeter. For example, the coating may have a different density from the process fluid. This can have an adverse effect on the density reading obtained from the flowmeter. For some process fluids, the coating may accumulate to a certain thickness inside the flowmeter and then break into small flakes. These small flakes may affect other parts of the process connected to the flowmeter. In extreme cases, the coating may accumulate enough to cause the flowmeter to become blocked, requiring a complete shutdown or, in some cases, the flowmeter to be completely replaced.

[0015] Other problems can arise from coatings, clogging, inconsistent process fluid composition, process fluid temperature variations, etc. For example, in the paint industry, the same flow meter can be used for multiple paint colors. Therefore, even though the coating may not cause meter reading errors, the coating can adversely affect the final product.

[0016] Because of the above problems, along with other problems caused by coatings, it is desirable to diagnose when a flow meter coating is present. Prior art diagnostic methods for detecting flow meter coatings have a number of problems. Limitations of the prior art occur in situations where the density of the coating is substantially similar to the process fluid. In these situations, density-based coating detection is not useful. Furthermore, in applications where it is known that the process fluid coats the flow meter, it is desirable to be able to detect when the meter is completely uncoated during cleaning of the flow meter.

[0017] Therefore, there is a need in the art for advanced meter verification including diagnostics for coating detection that overcomes the limitations noted above. In addition, there is a need for advanced flow meter verification including diagnostics that can easily confirm to an operator whether erosion, corrosion, or other meter damage has occurred to a particular flow meter and whether there may be flow measurement errors due to such erosion, corrosion, or other flow tube damage.

[0018] Furthermore, there is a need in the art to minimize the potential for false alarms and improve the detectability of flow calibration factor changes through better meter validation and diagnostics. Summary of the invention

[0019] The present invention overcomes the problems outlined above and advances the art by providing meter electronics for meter validation including diagnostics. Advantageously, the present invention allows for validation diagnostic parameters that provide a "go / no go result" regarding problems associated with coatings, erosion, corrosion and other meter damage.

[0020] Furthermore, the present invention advances the art through robust detectability of flow calibration factor changes and minimizes the potential for false alarms through better meter validation and diagnostics.

[0021] Aspects of the invention.

[0022] In one aspect of the invention, a vibrating flow meter for meter verification includes: a flow meter assembly including one or more flow tubes and first and second pickoff sensors; a driver configured to vibrate the one or more flow tubes; and meter electronics coupled to the first and second pickoff sensors and to the driver, wherein the meter electronics is configured to: vibrate the flow meter assembly in a single mode using the driver, determine a single-mode current of the driver and determine first and second response voltages generated by the first and second pickoff sensors, respectively, calculate a frequency response function for the determined first and second response voltages based on the determined single-mode current, fit the generated frequency response function to a pole-residue model to calculate meter stiffness, and use the meter stiffness value to verify proper operation of the vibrating flow meter.

[0023] Preferably, the gauge stiffness value includes a correction for density.

[0024] Preferably, the correction for density comprises calculating an expected stiffness.

[0025] Preferably, the gauge stiffness value includes a correction for pressure.

[0026] Preferably, the validation operation of the vibrating flow meter using the meter stiffness value comprises determining a difference between the meter stiffness value and a baseline meter stiffness, and wherein the difference is compared to a predetermined stiffness range.

[0027] Preferably, the meter electronics is further configured to compare the meter stiffness value to a predetermined stiffness range, generate a validation indication for the vibrating flow meter if the meter stiffness value falls within the predetermined stiffness range, and generate a non-validation indication for the vibrating flow meter if the meter stiffness value does not fall within the predetermined stiffness range.

[0028] Preferably, the meter electronics is further configured to calculate a difference in meter stiffness values ​​at the first pickoff sensor and the second pickoff sensor, and to use the calculated difference in meter stiffness values ​​to verify proper operation of the vibrating flow meter.

[0029] Preferably, the validation operation wherein the vibrating flow meter uses the calculated difference in meter stiffness values ​​comprises determining a difference between the calculated difference in meter stiffness values ​​and a baseline meter stiffness difference, and wherein the determined difference is compared to a predetermined stiffness difference range.

[0030] Preferably, the meter electronics is further configured to compare the calculated difference in meter stiffness values ​​to a predetermined stiffness difference range, generate a validation indication for the vibrating flow meter if the calculated difference in meter stiffness values ​​falls within the predetermined stiffness difference range, and generate a non-validation indication for the vibrating flow meter if the calculated difference in meter stiffness values ​​does not fall within the predetermined stiffness difference range.

[0031] In one aspect of the invention, a vibrating flow meter for meter verification includes: a flow meter assembly including one or more flow tubes and first and second pickoff sensors; a driver configured to vibrate the one or more flow tubes; and meter electronics coupled to the first and second pickoff sensors and to the driver, wherein the meter electronics is configured to: vibrate the flow meter assembly in a single mode using the driver, determine a single mode current of the driver and determine first and second response voltages generated by the first and second pickoff sensors, respectively, calculate a frequency response function for the determined first and second response voltages based on the determined single mode current, fit the generated frequency response function to a pole-residual residual deflection model, and use the residual deflection values ​​to verify proper operation of the vibrating flow meter.

[0032] Preferably, a validation operation of the vibrating flow meter using the residual deflection value comprises determining a difference between the residual deflection value and a baseline residual deflection, and wherein the difference is compared to a predetermined residual deflection range.

[0033] Preferably, the meter electronics is further configured to compare the residual deflection value to a predetermined residual deflection range, generate a validation indication for the vibrating flow meter if the residual deflection value falls within the predetermined residual deflection, and generate a non-validation indication for the vibrating flow meter if the residual deflection value does not fall within the predetermined residual deflection range.

[0034] Preferably, the meter electronics is further configured to calculate a difference in residual deflection values ​​at the first pickoff sensor and the second pickoff sensor, and to use the calculated difference in residual deflection values ​​to verify proper operation of the vibrating flow meter.

[0035] Preferably, the validation operation wherein the vibrating flow meter uses the calculated difference in residual deflection values ​​comprises determining a difference between the calculated difference in residual deflection values ​​and a baseline residual deflection difference, and wherein the determined difference is compared to a predetermined residual deflection difference range.

[0036] Preferably, the meter electronics is further configured to compare the calculated difference in residual deflection values ​​to a predetermined residual deflection difference range, generate a validation indication for the vibrating flow meter if the calculated difference in residual deflection values ​​falls within the predetermined residual deflection difference range, and generate a non-validation indication for the vibrating flow meter if the calculated difference in residual deflection values ​​does not fall within the predetermined residual deflection difference range.

[0037] In one aspect of the invention, a vibrating flow meter for meter verification includes: a flow meter assembly including one or more flow tubes and first and second pickoff sensors; a driver configured to vibrate the one or more flow tubes; and meter electronics coupled to the first and second pickoff sensors and to the driver, wherein the meter electronics is configured to: vibrate the flow meter assembly in a single mode using the driver, determine a single mode current of the driver and determine first and second response voltages generated by the first and second pickoff sensors, respectively, calculate a frequency response function for the determined first and second response voltages based on the determined single mode current, fit the generated frequency response function to a pole residual model to calculate a meter quality value, and use the meter quality value to verify proper operation of the vibrating flow meter.

[0038] Preferably, the meter electronics is further configured to calculate a difference in meter mass values ​​at the first pickoff sensor and the second pickoff sensor, and to use the calculated difference in meter mass values ​​to verify proper operation of the vibrating flow meter.

[0039] Preferably, the validation operation of the vibrating flow meter using the calculated difference in meter mass values ​​comprises determining a difference between the calculated difference in meter mass values ​​and a baseline meter mass difference, and wherein the determined difference is compared to a predetermined mass difference range.

[0040] Preferably, the meter electronics is further configured to compare the calculated difference in meter mass values ​​to a predetermined mass difference range, generate a validation indication for the vibrating flow meter if the calculated difference in meter mass values ​​falls within the predetermined mass difference range, and generate a non-validation indication for the vibrating flow meter if the calculated difference in meter mass values ​​does not fall within the predetermined mass difference range.

[0041] Preferably, the meter electronics is further configured to utilize the fluid density to calculate an expected mass deviation for the first pickoff sensor and the second pickoff sensor, and to use the expected mass deviation to verify proper operation of the vibrating flow meter.

[0042] Preferably, the fluid density comprises at least one of a measured fluid density and an input expected fluid density.

[0043] Preferably, the meter electronics is further configured to calculate a difference in expected mass deviation values ​​at the first pickoff sensor and the second pickoff sensor, and to use the calculated difference in expected mass deviation values ​​to verify proper operation of the vibrating flow meter.

[0044] Preferably, the validation operation wherein the vibrating flow meter uses the calculated difference in expected mass deviation values ​​comprises determining a difference between the calculated difference in expected mass deviation mass values ​​and a baseline expected mass deviation difference, and wherein the determined difference is compared to a predetermined expected mass deviation difference range.

[0045] Preferably, the meter electronics is further configured to compare the calculated difference in expected mass deviation values ​​to a predetermined difference range for expected mass deviations, generate a validation indication for the vibrating flow meter if the calculated difference in expected mass deviation values ​​falls within the predetermined difference range for expected mass deviations, and generate a non-validation indication for the vibrating flow meter if the calculated difference in expected mass deviation values ​​does not fall within the predetermined difference range for expected mass deviations.

[0046] In one aspect of the invention, a meter verification method for a vibrating flow meter, wherein the method includes: using a driver to vibrate a flow meter component of the vibrating flow meter in a single mode; determining a single mode current of the driver and determining first and second single mode response voltages generated by first and second pickoff sensors, respectively; calculating a frequency response function for the determined first and second response voltages based on the determined single mode current; fitting the generated frequency response function to a pole residual model to generate a meter stiffness; and using the meter stiffness value to verify proper operation of the vibrating flow meter.

[0047] Preferably, the gauge stiffness value includes a correction for density.

[0048] Preferably, wherein the correction for density comprises calculating an expected stiffness.

[0049] Preferably, the gauge stiffness value includes a correction for pressure.

[0050] Preferably, wherein the validation operation of the vibrating flow meter using the meter stiffness value comprises determining a difference between the meter stiffness value and a baseline meter stiffness, and wherein the difference is compared to a predetermined stiffness range.

[0051] Preferably, the meter electronics further comprises comparing the meter stiffness value to a predetermined stiffness range, generating a validation indication for the vibrating flow meter if the meter stiffness value falls within the predetermined stiffness range, and generating a non-validation indication for the vibrating flow meter if the meter stiffness value does not fall within the predetermined stiffness range.

[0052] Preferably, the meter electronics further comprises calculating a difference in meter stiffness values ​​at the first pickoff sensor and the second pickoff sensor, and using the calculated difference in meter stiffness values ​​to verify proper operation of the vibrating flow meter.

[0053] Preferably, the validation operation wherein the vibrating flow meter uses the calculated difference in meter stiffness values ​​comprises determining a difference between the calculated difference in meter stiffness values ​​and a baseline meter stiffness difference, and wherein the determined difference is compared to a predetermined stiffness difference range.

[0054] Preferably, the meter electronics further comprises comparing the calculated difference in meter stiffness values ​​to a predetermined stiffness difference range, generating a validation indication for the vibrating flow meter if the calculated difference in meter stiffness values ​​falls within the predetermined stiffness difference range, and generating a non-validation indication for the vibrating flow meter if the calculated difference in meter stiffness values ​​does not fall within the predetermined stiffness difference range.

[0055] In one aspect of the present invention, a meter verification method for a vibrating flow meter, wherein the method includes: using a driver to vibrate a flow meter component of the vibrating flow meter in a single mode; determining a single mode current of the driver and determining a first single mode response voltage and a second single mode response voltage generated by a first pickoff sensor and a second pickoff sensor, respectively; calculating a frequency response function for the determined first response voltage and second response voltage based on the determined single mode current; fitting the generated frequency response function to a pole residue residual deflection model; and using the residual deflection value to verify proper operation of the vibrating flow meter.

[0056] Preferably, the validation operation of the vibrating flow meter using the residual deflection value comprises determining a difference between the residual deflection value and a baseline residual deflection, and wherein the difference is compared to a predetermined residual deflection range.

[0057] Preferably, the meter electronics further comprises comparing the residual deflection value to a predetermined residual deflection range, generating a validation indication for the vibrating flow meter if the residual deflection value falls within the predetermined residual deflection, and generating a non-validation indication for the vibrating flow meter if the residual deflection value does not fall within the predetermined residual deflection range.

[0058] Preferably, the meter electronics further comprises calculating a difference in residual deflection values ​​at the first pickoff sensor and the second pickoff sensor, and using the calculated difference in residual deflection values ​​to verify proper operation of the vibrating flow meter.

[0059] Preferably, the validation operation wherein the vibrating flow meter uses the calculated difference in residual deflection values ​​comprises determining a difference between the calculated difference in residual deflection values ​​and a baseline residual deflection difference, and wherein the determined difference is compared to a predetermined residual deflection difference range.

[0060] Preferably, the meter electronics further comprises comparing the calculated difference in residual deflection values ​​to a predetermined residual deflection difference range, generating a validation indication for the vibrating flow meter if the calculated difference in residual deflection values ​​falls within the predetermined residual deflection difference range, and generating a non-validation indication for the vibrating flow meter if the calculated difference in residual deflection values ​​does not fall within the predetermined residual deflection difference range.

[0061] In one aspect of the invention, a meter verification method for a vibrating flow meter, wherein the method includes: using a driver to vibrate a flow meter component of the vibrating flow meter in a single mode; determining a single mode current of the driver and determining first and second single mode response voltages generated by first and second pickoff sensors, respectively; calculating a frequency response function for the determined first and second response voltages based on the determined single mode current; fitting the generated frequency response function to a pole residue model to generate a meter quality value; and using the meter quality value to verify proper operation of the vibrating flow meter.

[0062] Preferably, the meter electronics further comprises calculating a difference in meter mass values ​​at the first pickoff sensor and the second pickoff sensor, and using the calculated difference in meter mass values ​​to verify proper operation of the vibrating flow meter.

[0063] Preferably, the validation operation wherein the vibrating flow meter uses the calculated difference in meter mass values ​​comprises determining a difference between the calculated difference in meter mass values ​​and a baseline meter mass difference, and wherein the determined difference is compared to a predetermined mass difference range.

[0064] Preferably, the meter electronics further comprises comparing the calculated difference in meter mass values ​​to a predetermined mass difference range, generating a validation indication for the vibrating flow meter if the calculated difference in meter mass values ​​falls within the predetermined mass difference range, and generating a non-validation indication for the vibrating flow meter if the calculated difference in meter mass values ​​does not fall within the predetermined mass difference range.

[0065] Preferably, the meter electronics further comprises calculating an expected mass deviation for the first pickoff sensor and the second pickoff sensor using the fluid density, and using the expected mass deviation to verify proper operation of the vibrating flow meter.

[0066] Preferably, the fluid density comprises at least one of a measured fluid density and an input expected fluid density.

[0067] Preferably, the meter electronics further comprises calculating a difference in expected mass deviation values ​​at the first pickoff sensor and the second pickoff sensor, and using the calculated difference in expected mass deviation values ​​to verify proper operation of the vibrating flow meter.

[0068] Preferably, the validation operation wherein the vibrating flow meter uses the calculated difference in expected mass deviation values ​​comprises determining a difference between the calculated difference in expected mass deviation mass values ​​and a baseline expected mass deviation difference, and wherein the determined difference is compared to a predetermined expected mass deviation difference range.

[0069] Preferably, the meter electronics further comprises comparing the calculated difference in expected mass deviation values ​​to a predetermined difference range of expected mass deviations, generating a validation indication for the vibrating flow meter if the calculated difference in expected mass deviation values ​​falls within the predetermined difference range of expected mass deviations, and generating a non-validation indication for the vibrating flow meter if the calculated difference in expected mass deviation values ​​does not fall within the predetermined difference range of expected mass deviations. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Like reference numbers refer to like elements throughout the drawings. The drawings are not necessarily drawn to scale.

[0071] Figure 1 A vibrating flow meter for meter verification according to an embodiment of the present invention is shown.

[0072] Figure 2 Meter electronics for meter verification of a vibrating flow meter according to an embodiment of the present invention is shown.

[0073] Figure 3 is a graph of frequency response showing the effect of residual deflection.

[0074] Figure 4 A vibrating flow meter with curved flow tubes is shown, wherein two parallel curved flow tubes are vibrated in a bending mode.

[0075] Figure 5 is a flow chart of a meter verification method for a vibrating flow meter according to an embodiment of the present invention.

[0076] Figure 6 is a flow chart of a meter verification method for a vibrating flow meter according to an embodiment of the present invention.

[0077] Figure 7 is a flow chart of a meter verification method for a vibrating flow meter according to an embodiment of the present invention.

[0078] Figure 8 Diagnostics according to example embodiments are shown.

[0079] Fig. 9 A diagnostic according to an example embodiment is shown that utilizes the difference between left pickup (LPO) stiffness data and right pickup (RPO) stiffness data as a parameter.

[0080] Fig.10 A separate example model instance is shown for the location of damage to a corroded or eroded gauge.

[0081] Fig.11 A graph representing flow rate error due to pipe wall erosion and / or corrosion is shown.

[0082] Fig.12 A graph showing changes in gauge proof stiffness due to pipe wall erosion and / or corrosion is shown.

[0083] Fig.13 A graph showing the change in residual deflection (RF) relative to the change in FCF is shown.

[0084] Fig.14 Diagnosis using the difference between the residual deflections of the first pickoff sensor 170L and the second pickoff sensor 170R is shown.

[0085] Fig.15 An example smart meter validation graph is shown showing percentage changes in mass deviation for a left pick-off (LPO) sensor and a right pick-off (RPO) sensor.

[0086] Fig.16 A diagnostic according to an example embodiment is shown that utilizes the difference between left pick-off (LPO) mass deviation and right pick-off (RPO) mass deviation data as a parameter.

[0087] Fig.17 An example smart meter validation graph showing density for various runs is shown.

[0088] Fig.18 An example smart meter validation graph showing density for various runs is shown. DETAILED DESCRIPTION

[0089] Figures 1 to 18 And the following description describes specific examples to teach those skilled in the art how to obtain and use the best mode of the present invention. For the purpose of teaching the principles of the invention, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate the variations from these examples that fall within the scope of the present invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the present invention. Therefore, the present invention is not limited to the specific examples described below, but is only limited by the claims and their equivalents.

[0090] Figure 1 A flow meter 5 is shown including a meter assembly 10 and meter electronics 20. The meter assembly 10 is responsive to the mass flow rate and density of a process material. The meter electronics 20 is connected to the meter assembly 10 via leads 100 to provide density, mass flow rate, and temperature information via path 26, as well as other information not relevant to the present invention. A Coriolis flow meter structure is described, however it will be apparent to one skilled in the art that the present invention may be practiced as a vibrating tube densitometer without the additional measurement capabilities provided by a Coriolis mass flow meter.

[0091] The meter assembly 10 includes a pair of manifolds 150 and 150', flanges 103 and 103' having flange necks 110 and 110', a pair of parallel flow tubes 130 and 130', a drive mechanism 180, a temperature sensor 190, and a pair of velocity sensors 170L and 170R. The flow tubes 130 and 130' have two substantially straight inlet struts 131 and 131' and outlet struts 134 and 134' that converge toward each other at the flow tube mounting blocks 120 and 120'. The flow tubes 130 and 130' are bent at two symmetrical locations along their length and are substantially parallel throughout their length. The struts 140 and 140' are used to define axes W and W' about which each flow tube oscillates.

[0092] The side struts 131, 131' and 134, 134' of the flow tubes 130 and 130' are fixedly attached to the flow tube mounting blocks 120 and 120', and these blocks are in turn fixedly attached to the manifolds 150 and 150'. This provides a continuous closed material path through the Coriolis meter assembly 10.

[0093] When flanges 103 and 103' having holes 102 and 102' are connected via inlet end 104 and outlet end 104' to a process line (not shown) carrying the process material to be measured, material entering end 104 of the meter through orifice 101 in flange 103 is directed through manifold 150 to flow tube mounting block 120 having surface 121. Within manifold 150, the material is separated and routed through flow tubes 130 and 130'. Upon exiting flow tubes 130 and 130', the process material is reassembled into a single stream within manifold 150' and is thereafter routed to outlet end 104' connected by flange 103' having bolt holes 102' to reach a process line (not shown).

[0094] Flow tubes 130 and 130' are selected and appropriately mounted to flow tube mounting blocks 120 and 120', respectively, so as to have substantially the same mass distribution, moment of inertia and Young's modulus about bending axes WW and W'-W'. These bending axes pass through struts 140 and 140'. Since the Young's modulus of the flow tube changes with temperature, and this change affects the calculation of flow and density, a resistance temperature detector (RTD) 190 is mounted to the flow tube 130' to continuously measure the temperature of the flow tube. The temperature of the flow tube and therefore the voltage appearing across it for a given current through the RTD is governed by the temperature of the material passing through the flow tube. In a known method, the meter electronics 20 uses the temperature-dependent voltage appearing across the RTD to compensate for changes in the elastic modulus of the flow tubes 130 and 130' caused by any changes in the flow tube temperature. The RTD is connected to the meter electronics 20 via leads 195.

[0095] Both flow tubes 130 and 130' are driven by a driver 180 in opposite directions about their respective bending axes W and W', and this is referred to as the first out-of-phase bending mode of the flow meter. The drive mechanism 180 may include any of a number of well-known arrangements, such as a magnet mounted to flow tube 130' and an opposing coil mounted to flow tube 130 and an alternating current passed through them to vibrate the two flow tubes. An appropriate drive signal is applied to the drive mechanism 180 by the meter electronics 20 via leads 185.

[0096] Meter electronics 20 receives the RTD temperature signal on lead 195, and the left and right velocity signals appearing on leads 165L and 165R, respectively. Meter electronics 20 generates a drive signal appearing on lead 185 to drive element 180 and vibrate tubes 130 and 130'. Meter electronics 20 processes the left and right velocity signals and the RTD signal to calculate the mass flow rate and density of the material passing through meter assembly 10. This information, along with other information, is applied by meter electronics 20 to utilization device 29 via path 26.

[0097] Figure 2 Meter electronics 20 according to an embodiment of the present invention is shown. Meter electronics 20 may include an interface 201 and a processing system 203. Meter electronics 20 receives a vibration response 208, such as from meter assembly 10, for example. Meter electronics 20 processes vibration response 208 to obtain flow characteristics of a flowing material flowing through meter assembly 10.

[0098] As previously discussed, the flow calibration factor (FCF) reflects the material properties and the cross-sectional properties of the flow tube. The mass flow rate of the flow material flowing through the flow meter is determined by multiplying the measured time delay (or phase difference / frequency) by the FCF. The FCF can be related to the stiffness characteristics of the meter assembly. If the stiffness characteristics of the meter assembly change, the FCF will also change. Therefore, changes in the stiffness of the flow meter will affect the accuracy of the flow measurement results generated by the flow meter.

[0099] Interface 201 via Figure 1 The interface 201 may receive a vibration response 208 from one of the velocity sensors 170L and 170R at the lead 100. The interface 201 may perform any necessary or desired signal conditioning, such as any manner of formatting, amplification, buffering, etc. Alternatively, some or all of the signal conditioning may be performed in the processing system 203. In addition, the interface 201 may enable communication between the meter electronics 20 and an external device. The interface 201 may be capable of any manner of electronic, optical, or wireless communication.

[0100] In one embodiment, the interface 201 is coupled to a digitizer (not shown), wherein the sensor signal comprises an analog sensor signal. The digitizer samples and digitizes the analog vibration response and generates a digital vibration response 208 .

[0101] The processing system 203 directs the operation of the meter electronics 20 and processes flow measurements from the flow meter assembly 10. The processing system 203 executes one or more processing routines and thereby processes the flow measurements to produce one or more flow characteristics.

[0102] Processing system 203 may include a general purpose computer, a microprocessing system, a logic circuit, or some other general or custom processing device. Processing system 203 may be distributed among multiple processing devices. Processing system 203 may include any manner of integral or independent electronic storage media, such as storage system 204.

[0103] The storage system 204 may store flow meter parameters and data, software routines, constant values, and variable values. In one embodiment, the storage system 204 includes routines executed by the processing system 203, such as the operation routine 210 and the verification routine 213 of the flow meter 5.

[0104] The storage system 204 may store a meter stiffness value 216. The meter stiffness value 216 includes a stiffness value determined based on a vibration response generated during operation of the vibrating flow meter 5. The meter stiffness value 216 may be generated to verify proper operation of the vibrating flow meter 5. The meter stiffness value 216 may be generated for a verification process, wherein the meter stiffness value 216 serves the purpose of verifying proper and accurate operation of the vibrating flow meter 5.

[0105] The storage system 204 can store expected stiffness values ​​217. The expected stiffness can be developed based on the plant air and water baseline stiffness 209 and used to normalize the measured stiffness, thereby removing any density dependence. The expected stiffness calculation is described in the following paragraphs. The expected stiffness 217 can be generated to verify the proper operation of the vibrating flow meter 5.

[0106] The storage system 204 may store a single mode current 230. The single mode drive current 230 may include one or more drive / excitation currents for generating a single vibration mode and a meter verification signal in the flow meter assembly 5. The single mode drive current 230 may include a current from the driver 180. The single mode current 230 may include a command current for a single vibration mode (i.e., a current specified for the driver 180) or may include a measured current for a single vibration mode (i.e., a current measured when actually flowing through the driver).

[0107] The storage system 204 may store a single mode response voltage 231. The primary mode response voltage 231 may include a sinusoidal voltage signal or voltage level generated in response to the vibration mode. The single mode response voltage 231 may include a voltage signal or voltage level (such as a peak voltage) generated by one or both of the first pickup sensor 170L and the second pickup sensor 170R. The response voltage will also include a response at the meter verification excitation signal frequency. In some embodiments, the storage system 204 may store a single mode response voltage 231 corresponding to the first pickup sensor 170L and the second pickup sensor 170R.

[0108] The gauge stiffness value 216 may be generated based on measurements or information generated during a single vibration mode.

[0109] The vibration response of a flow meter can be represented by an open-loop, second-order drive model, including:

[0110] (3),

[0111] where f is the force applied to the system, M is the mass parameter of the system, C is the damping parameter, and K is the stiffness parameter. The term ζ includes the decay characteristics. The term x is the physical displacement distance of the vibration, and the term is the velocity of the flow tube displacement, and the term is the acceleration. This is often referred to as the MCK model. The formula can be rearranged into the following form:

[0112] (4).

[0113] Ignoring the initial conditions, equation (4) can be further manipulated into a transfer function form. The result is:

[0114] (5).

[0115] Further operations can transform equation (5) into a first-order pole-residual frequency response function form, including:

[0116] (6),

[0117] where λ is the pole, R is the residual, the term (j) comprises the square root of -1, and ω is the cyclic excitation frequency in radians per second.

[0118] The poles define the natural / resonant frequency (ω n ), damped natural frequency (ω d ) and decay characteristics (ζ).

[0119] (7)

[0120] (8)

[0121] (9).

[0122] The stiffness parameters (K), damping parameters (C), and mass parameters (M) of the system can be derived from the poles and residuals.

[0123] (10)

[0124] (11)

[0125] (12).

[0126] Therefore, the stiffness parameters (K), mass parameters (M), and damping parameters (C) can be calculated based on good estimates of the poles (λ) and residuals (R).

[0127] The poles and the residuals are estimated from the measured frequency response function (FRF). For example, an iterative calculation method can be used to estimate the poles (λ) and the residuals (R).

[0128] The storage system 204 can store the baseline meter stiffness 209 for air and water that is programmed into the meter electronics 20. In some embodiments, the baseline meter stiffness 209 for air and water can be programmed into the meter electronics 20 at the factory (or other manufacturer facility), such as when the vibrating flow meter 5 is constructed or sold. Alternatively, the baseline meter stiffness 209 for air and water can be programmed into the meter electronics 20 during a field calibration operation or other calibration or recalibration operation. However, it should be understood that in most embodiments, the baseline meter stiffness 209 for air and water will not be changeable by a user or operator or during field operation of the vibrating flow meter 5.

[0129] If the meter stiffness value 216 is substantially the same as the baseline meter stiffness 209, then it can be determined that the vibrating flow meter 5 is relatively unchanged from the condition when it was manufactured, calibrated, or when the vibrating flow meter 5 was last recalibrated. Alternatively, in the event that the meter stiffness value 216 is significantly different from the baseline meter stiffness 209, then it can be determined that the vibrating flow meter 5 has been degraded and is unable to operate accurately and reliably, such as in the case where the vibrating flow meter 5 has been altered due to metal fatigue, corrosion, erosion due to flow, or other operating conditions or influences.

[0130] The storage system 204 can store a predetermined stiffness range 219. The predetermined stiffness range 219 includes a selected range of acceptable stiffness values. The predetermined stiffness range 219 can be selected to account for corrosion or erosion in the vibrating flow meter 5.

[0131] In one embodiment, the storage system 204 stores a baseline meter stiffness difference 224. In some embodiments, the baseline meter stiffness difference 224 may be programmed into the meter electronics 20 at the factory (or other manufacturer facility), such as when the vibrating flow meter 5 is constructed or sold. Alternatively, the baseline meter stiffness difference 224 may be programmed into the meter electronics 20 during a field calibration operation or other calibration or recalibration operation. However, it should be understood that in most embodiments, the baseline meter stiffness difference 224 will not be changeable by a user or operator or during field operation of the vibrating flow meter 5.

[0132] If the difference in meter stiffness values ​​at the first pickoff sensor 170L and the second pickoff sensor 170R is substantially the same as the baseline meter stiffness difference 224, then it can be determined that the condition of the vibrating flow meter 5 is relatively unchanged from when it was manufactured, calibrated, or when the vibrating flow meter 5 was last recalibrated. Alternatively, in the event that the difference in meter stiffness values ​​at the first pickoff sensor 170L and the second pickoff sensor 170R is significantly different from the baseline meter stiffness difference 224, then it can be determined that the vibrating flow meter 5 has been degraded and may not be able to operate accurately and reliably, such as in the case where the vibrating flow meter 5 has been altered due to metal fatigue, corrosion, erosion due to flow, or other operating conditions or influences.

[0133] In one embodiment, the storage system 204 stores a predetermined meter stiffness difference range 225. The predetermined meter stiffness difference range 225 includes a selected range of acceptable meter stiffness difference values. The predetermined meter stiffness difference range 225 may be selected to account for corrosion or erosion in the vibrating flow meter 5.

[0134] In one embodiment, the storage system 204 stores meter residual deflection 218. The meter residual deflection 218 includes residual deflection values ​​determined based on vibration responses generated during operation of the vibrating flow meter 5. Determining the residual deflection requires only additional curve fitting during stiffness calculations and, in some embodiments, only additional iterations of the fitting algorithm or process for equation (16).

[0135] Figure 3 is a graph of three FRFs showing the effect of residual deflection, plotted as amplitude (A) versus frequency (f). Amplitude peak FRF1 occurs at the first resonant frequency ω1. Amplitude peaks FRF2 and FRF3 occur at resonant frequencies ω2 and ω3. As can be seen from the graph, FRF2 and FRF3 have tails that affect the amplitude value of FRF1, including at the resonant frequency ω1. The effect of the tails of FRF2 and FRF3 on the vibration at the resonant frequency ω1 is called residual deflection. Similarly, FRF2 shows the residual deflection effect of the tail of FRF3.

[0136] Note that in the preferred FRF measurement, two FRFs are measured for a particular drive frequency and vibration response. One FRF measurement is obtained from the drive to the right pick-off (RPO), and one FRF measurement is obtained from the drive to the left pick-off (LPO). This method is called Single Input Multiple Output (SIMO). Recognizing that the two FRFs share a common pole (λ), but separate residuals (R L ) and (R R ), the two measurement results can be advantageously combined to result in a robust pole and residual determination.

[0137] (13).

[0138] Equation (13) can be solved in many ways. In one embodiment, the equation is solved by recursive least squares. In another embodiment, the equation is solved by a pseudo-inverse technique. In yet another embodiment, since all measurements are available simultaneously, a standard QR decomposition technique can be used. The QR decomposition technique is discussed in Modern Control Theory, William Brogan, copyright 1991, Prentice Hall, pp. 222-224, 168-172.

[0139] Reference again Figure 2 , a meter residual deflection 218 may be generated to verify proper operation of the vibrating flow meter 5. The meter residual deflection 218 may be generated for use in a verification process, wherein the meter residual deflection 218 serves the purpose of verifying proper and accurate operation of the vibrating flow meter 5.

[0140] The pole-residual model can be modified to include a single residual deflection term Φ to account for the aggregate effect of other modes. This effect is assumed to be constant where the frequency is within the local measurements near the driven mode. This will be true if all other modes are at higher frequencies than the driven mode and are far enough away to be considered pure stiffness. The modified pole-residual model is now called the pole-residual residual deflection model:

[0141] (14),

[0142] The model can be converted to a velocity FRF and the terms can be rearranged to obtain a more easily solvable form:

[0143] (15),

[0144] Equation 15 can be expressed in a form similar to that of Equation 13, which is a form that is easily solved using techniques from linear algebra (discussed after Equation 13).

[0145] (16).

[0146] According to the unknown term R, and , the equation is no longer strictly linear. Instead, and The terms are interdependent. This can be handled via a simple iterative solution technique. The model is first solved without the residual deflection term (using equation 13) to obtain an initial pole estimate. This estimate is used to seed the initial iteration of equation 16. This method works quite well because the pole estimate is quite insensitive to relatively small residual deflections, much less sensitive than to residuals. Because new pole estimates are generated each time equation (16) is evaluated, the iterative technique can be repeated until the poles are stable (although in practice a single iteration may be sufficient). In an online implementation, where system parameters are calculated for many sequence measurements in a timely manner, it is more useful or efficient to seed the estimates of the poles with values ​​from the previous time window, rather than starting from zero each time in the case of a model without residual deflections.

[0147] In one embodiment, the storage system 204 stores a baseline meter residual deflection 220. In some embodiments, the baseline meter residual deflection 220 may be programmed into the meter electronics 20 at the factory (or other manufacturer facility), such as when the vibrating flow meter 5 is constructed or sold. Alternatively, the baseline meter residual deflection 220 may be programmed into the meter electronics 20 during a field calibration operation or other calibration or recalibration operation. However, it should be understood that in most embodiments, the baseline meter residual deflection 220 will not be changeable by a user or operator or during field operation of the vibrating flow meter 5.

[0148] If the residual deflection 218 is substantially the same as the baseline meter residual deflection 220, then it can be determined that the vibrating flow meter 5 is relatively unchanged from the condition when it was manufactured, calibrated, or when the vibrating flow meter 5 was last recalibrated. Alternatively, in the event that the residual deflection 218 is significantly different from the baseline meter residual deflection 220, then it can be determined that the vibrating flow meter 5 has been degraded and is unable to operate accurately and reliably, such as in the case where the vibrating flow meter 5 has been altered due to metal fatigue, corrosion, erosion due to flow, or other operating conditions or influences.

[0149] In one embodiment, the storage system 204 stores a predetermined residual deflection range 221. The predetermined residual deflection range 221 includes a selected range of acceptable residual deflection values. The predetermined residual deflection range 221 may be selected to account for corrosion or erosion in the vibrating flow meter 5.

[0150] In one embodiment, the storage system 204 stores a baseline meter residual deflection difference 226. In some embodiments, the baseline meter residual deflection difference 226 may be programmed into the meter electronics 20 at the factory (or other manufacturer facility), such as when the vibrating flow meter 5 is constructed or sold. Alternatively, the baseline meter residual deflection difference 226 may be programmed into the meter electronics 20 during a field calibration operation or other calibration or recalibration operation. However, it should be understood that in most embodiments, the baseline meter residual deflection difference 226 will not be changeable by a user or operator or during field operation of the vibrating flow meter 5.

[0151] If the difference in residual deflection values ​​at the first pickoff sensor 170L and the second pickoff sensor 170R is substantially the same as the baseline meter residual deflection difference 226, then it can be determined that the vibrating flow meter 5 is relatively unchanged from the condition when it was manufactured, calibrated, or when the vibrating flow meter 5 was last recalibrated. Alternatively, in the event that the difference in residual deflection values ​​at the first pickoff sensor 170L and the second pickoff sensor 170R is significantly different from the baseline meter residual deflection difference 226, then it can be determined that the vibrating flow meter 5 has been degraded and may not be able to operate accurately and reliably, such as in the case where the vibrating flow meter 5 has been altered due to metal fatigue, corrosion, erosion due to flow, or other operating conditions or influences.

[0152] In one embodiment, the storage system 204 stores a predetermined residual deflection difference range 227. The predetermined residual deflection difference range 227 includes a selected range of acceptable residual deflection difference values. The predetermined residual deflection difference range 227 may be selected to account for corrosion or erosion in the vibrating flow meter 5.

[0153] The storage system 204 may store a meter quality value 240. The meter quality value 240 includes a meter quality value determined based on a vibration response generated during operation of the vibrating flow meter 5. The meter quality value 240 may be generated to verify proper operation of the vibrating flow meter 5. The meter quality value 240 may be generated for a verification process, wherein the meter quality value 240 serves the purpose of verifying proper and accurate operation of the vibrating flow meter 5.

[0154] In one embodiment, the storage system 204 stores baseline quality values ​​241 for air and water. In some embodiments, the baseline quality values ​​241 for air and water may be programmed into the meter electronics 20 at the factory (or other manufacturer facility), such as when the vibrating flow meter 5 is constructed or sold. Alternatively, the baseline quality values ​​241 for air and water may be programmed into the meter electronics 20 during a field calibration operation or other calibration or recalibration operation. However, it should be understood that in most embodiments, the baseline quality values ​​241 for air and water will not be changeable by a user or operator or during field operation of the vibrating flow meter 5.

[0155] If the mass value 240 is substantially the same as the baseline mass value 241 for air and water, then it can be determined that the vibrating flow meter 5 is relatively unchanged from the condition when it was manufactured, calibrated, or when the vibrating flow meter 5 was last recalibrated. Alternatively, in the event that the mass value 240 is significantly different from the baseline mass value 241 for air and water, then it can be determined that the vibrating flow meter 5 has been degraded and is unable to operate accurately and reliably, such as in the case where the vibrating flow meter 5 has been altered due to metal fatigue, corrosion, erosion due to flow, or other operating conditions or influences.

[0156] In one embodiment, the storage system 204 stores a predetermined quality value range 242. The predetermined quality value range 242 includes a selected range of acceptable quality values. The predetermined quality value range 242 may be selected to account for corrosion or erosion in the vibrating flow meter 5.

[0157] In one embodiment, the storage system 204 stores a baseline meter quality difference 245. In some embodiments, the baseline meter quality difference 245 may be programmed into the meter electronics 20 at the factory (or other manufacturer facility), such as when the vibrating flow meter 5 is constructed or sold. Alternatively, the baseline meter quality difference 245 may be programmed into the meter electronics 20 during a field calibration operation or other calibration or recalibration operation. However, it should be understood that in most embodiments, the baseline meter quality difference 245 will not be changeable by a user or operator or during field operation of the vibrating flow meter 5.

[0158] If the difference in meter quality values ​​at the first pickoff sensor 170L and the second pickoff sensor 170R is substantially the same as the baseline meter quality difference 245, then it can be determined that the condition of the vibrating flow meter 5 is relatively unchanged from when it was manufactured, calibrated, or when the vibrating flow meter 5 was last recalibrated. Alternatively, in the event that the difference in meter quality values ​​at the first pickoff sensor 170L and the second pickoff sensor 170R is significantly different from the baseline meter quality difference 245, then it can be determined that the vibrating flow meter 5 has been degraded and may not be able to operate accurately and reliably, such as in the case where the vibrating flow meter 5 has been altered due to metal fatigue, corrosion, erosion due to flow, or other operating conditions or influences.

[0159] In one embodiment, the storage system 204 stores a predetermined meter quality difference range 246. The predetermined meter quality difference range 246 includes a selected range of acceptable meter quality difference values. The predetermined meter quality difference range 246 may be selected to account for corrosion or erosion in the vibrating flow meter 5.

[0160] The storage system 204 can store an expected mass deviation 250. The expected mass deviation 250 includes an expected mass deviation 250 determined based on the air and water quality 241 of the plant baseline and the known density of the process fluid. The calculation of the expected mass deviation is described in the following paragraphs. The expected mass deviation 250 can be generated to verify the proper operation of the vibrating flow meter 5. The expected mass deviation 250 can be generated for a verification process, wherein the expected mass deviation 250 serves the purpose of verifying the proper and accurate operation of the vibrating flow meter 5.

[0161] In one embodiment, the storage system 204 stores a baseline expected mass deviation 251. In some embodiments, the baseline expected mass deviation 251 may be programmed into the meter electronics 20 at the factory (or other manufacturer facility), such as when the vibrating flow meter 5 is constructed or sold. Alternatively, the baseline expected mass deviation value 251 may be programmed into the meter electronics 20 during a field calibration operation or other calibration or recalibration operation. However, it should be understood that in most embodiments, the baseline expected mass deviation 251 will not be changeable by a user or operator or during field operation of the vibrating flow meter 5.

[0162] If the expected mass deviation 250 is substantially the same as the baseline expected mass deviation 251, then it can be determined that the vibrating flow meter 5 is relatively unchanged from the condition when it was manufactured, calibrated, or when the vibrating flow meter 5 was last recalibrated. Alternatively, in the event that the expected mass deviation 250 is significantly different from the baseline expected mass deviation 251, then it can be determined that the vibrating flow meter 5 has been degraded and may not be able to operate accurately and reliably, such as in the case where the vibrating flow meter 5 has been altered due to metal fatigue, corrosion, erosion due to flow, or other operating conditions or influences.

[0163] In one embodiment, the storage system 204 stores a predetermined expected mass deviation range 252. The predetermined expected mass deviation range 252 includes a selected range of acceptable expected mass deviation values. The predetermined expected mass deviation value range 252 can be selected to account for corrosion or erosion in the vibrating flow meter 5.

[0164] In one embodiment, the storage system 204 stores the baseline expected mass deviation difference 255. In some embodiments, the baseline expected mass deviation difference 255 may be programmed into the meter electronics 20 at the factory (or other manufacturer facility), such as when the vibrating flow meter 5 is constructed or sold. Alternatively, the baseline expected mass deviation difference 255 may be programmed into the meter electronics 20 during a field calibration operation or other calibration or recalibration operation. However, it should be understood that in most embodiments, the baseline expected mass deviation difference 255 will not be changeable by a user or operator or during field operation of the vibrating flow meter 5.

[0165] If the difference in expected mass deviation values ​​at the first pickoff sensor 170L and the second pickoff sensor 170R is substantially the same as the difference in baseline meter mass deviation 255, then it can be determined that the condition of the vibrating flow meter 5 is relatively unchanged from when it was manufactured, calibrated, or when the vibrating flow meter 5 was last recalibrated. Alternatively, in the event that the difference in expected mass deviation values ​​at the first pickoff sensor 170L and the second pickoff sensor 170R is significantly different from the baseline expected mass deviation difference 255, then it can be determined that the vibrating flow meter 5 has been degraded and may not be able to operate accurately and reliably, such as in the case where the vibrating flow meter 5 has been altered due to metal fatigue, corrosion, erosion due to flow, or other operating conditions or influences.

[0166] In one embodiment, the storage system 204 stores a predetermined difference range 256 of expected mass deviations. The predetermined difference range 256 of expected mass deviations includes a selected range of acceptable difference values ​​of expected mass deviations. The predetermined difference range 256 of expected mass deviations can be selected to account for corrosion or erosion in the vibrating flow meter 5.

[0167] The storage system 204 may store density values ​​260. The density values ​​260 include density values ​​determined based on vibration responses generated during operation of the vibrating flow meter 5. The density values ​​260 may be generated to verify proper operation of the vibrating flow meter 5. The density values ​​260 may be generated for a verification process, wherein the density values ​​260 serve the purpose of verifying proper and accurate operation of the vibrating flow meter 5.

[0168] The storage system 204 can store a damping value 270. The damping value 270 includes a density value determined based on a vibration response generated during operation of the vibrating flow meter 5. The damping value 270 can be generated to verify proper operation of the vibrating flow meter 5. The damping value 270 can be generated for a verification process, wherein the damping value 270 serves the purpose of verifying proper and accurate operation of the vibrating flow meter 5.

[0169] In one embodiment, the storage system 204 stores an operating routine 210. When executed by the processing system 203, the operating routine 210 operates the vibrating flow meter 5, including vibrating the flow meter assembly 10, receiving subsequent first and second sensor signals, and generating one or more flow characteristics based on the first and second sensor signals. The operating routine 210 may also perform other operations, including, for example, communication operations and meter verification operations. Other meter operations are contemplated and within the scope of the description and claims.

[0170] In some embodiments, the storage system 204 stores a verification routine 213. When executed by the processing system 203, the verification routine 213 can perform a verification process of the vibrating flow meter 5. In an example embodiment, when executing the verification routine 213, the processing system 203 is configured to generate meter stiffness, residual deflection, mass, expected mass deviation, density, and damping values. In some embodiments, when executing the verification routine 213, the processing system 203 is configured to generate a meter stiffness value and use the meter stiffness value to verify the proper operation of the vibrating flow meter. In some embodiments, when executing the verification routine 213, the processing system 203 is configured to generate a meter residual deflection value and use the meter residual deflection value to verify the proper operation of the vibrating flow meter. In some embodiments, when executing the verification routine 213, the processing system 203 is configured to generate a meter mass value and use the meter mass value to verify the proper operation of the vibrating flow meter. In some embodiments, when executing the verification routine 213, the processing system 203 is configured to generate an expected mass deviation value and use the meter expected mass deviation value to verify proper operation of the vibrating flow meter. In some embodiments, when executing the verification routine 213, the processing system 203 is configured to generate a density value and use the meter density value to verify proper operation of the vibrating flow meter. In some embodiments, when executing the verification routine 213, the processing system 203 is configured to generate a damping value and use the meter damping value to verify proper operation of the vibrating flow meter.

[0171] Figure 4 1 shows a vibrating flow meter 5 with curved flow tubes 130 and 130', wherein two parallel curved flow tubes 130 and 130' vibrate in a bending mode. The dashed lines in the figure show the remaining positions of the two flow tubes 130 and 130'. In the bending mode, each tube vibrates about a bending axis W--W and W'--W'. Therefore, the flow tubes 130 and 130' periodically move away from each other (as shown by the curved arrows) and then move closer to each other. It can be seen that each flow tube 130 and 130' moves as a whole about the bending axis W--W and W'--W'.

[0172] Figure 5 5 is a flow chart of a meter verification method for a vibrating flow meter according to an embodiment of the present invention. In step 501, a meter component of a vibrating flow meter is vibrated in a vibration mode to generate a single-mode vibration response. The single-mode vibration response includes an electrical signal generated by a first pickoff sensor 170L and a second pickoff sensor 170R.

[0173] In some embodiments, the single vibration mode may include a bending mode.It should also be understood that vibrating the flow meter assembly in a single vibration mode includes vibrating in the single vibration mode and substantially at a resonant frequency for the predetermined vibration mode.

[0174] In step 502, a single mode current is determined as the current flowing through the driver. The current may include a command value of the current or may include a current value measured for the driver 190. In addition, a first response voltage and a second response voltage are determined at the first pickup sensor 170L and the second pickup sensor 170R, respectively. The first response voltage and the second response voltage are response voltages generated by the first pickup sensor and the second pickup sensor. The first response voltage and the second response voltage of the single mode may include voltages generated when operating at or near the resonant frequency of the single vibration mode.

[0175] In step 503 , a frequency response function (FRF) is generated for a first response voltage and a second response voltage determined according to the determined single mode current.

[0176] In step 504, the generated frequency response function is fit to the pole-residual model described in the previous paragraph. The pole-residual frequency response takes the form given in Equation 13. Alternatively, the pole-residual residual flexibility response may be used as shown in Equation 16.

[0177] In step 505, a gauge stiffness value is generated. The gauge stiffness value may be generated using Eq. 11.

[0178] In step 506, the gauge stiffness value is corrected for density. In gauge validation, there has previously been no need to correct for density. Indeed, by its definition, a fluid has no stiffness and therefore will not affect the measured tube stiffness. However, in newer sensor designs, changes in fluid density may change the structural dynamics so that the measured tube stiffness may change with density. There is also the possibility that the signal processing is sensitive to frequency or other differences in newer sensor designs that will also cause stiffness to be a function of density. Whatever causes the stiffness to change with density, it can be corrected.

[0179] The expected stiffness can be developed from the factory air and water baseline stiffness and is used to normalize the measured stiffness, thereby eliminating any density dependence. The expected stiffness calculation is shown in the following equation:

[0180] (17),

[0181] The expected normalization of stiffness is shown in Equation 18 below, where StiffnessUncertainty measuredis the current gauge verification temperature corrected stiffness measurement. Equation (18) is repeated for both the left pickoff sensor 170L and the right pickoff sensor 170R.

[0182] (18).

[0183] In step 507, the gauge stiffness value is corrected for pressure by the following equation:

[0184] (19),

[0185] Equation 19 shows the form of the pressure correction, where K p is the stiffness compensation factor for pressure and P is the pressure. P can be a fixed value entered by the user or an external pressure measurement brought into the transmitter. This value P can be the same as P used for mass flow and density correction. K must be determined for each sensor size p . K p The determination of is straightforward, simply measuring the stiffness at two pressures and performing a linear fit. Because secondary effects such as the direct pressure effect K p Will be different from the density-pressure coefficient.

[0186] The newly generated gage stiffness value is compared to the baseline gage stiffness in step 508. If the gage stiffness value is within the predetermined stiffness range, the method branches to step 509. If the gage stiffness value is not within the predetermined stiffness range, the method branches to step 510.

[0187] The comparison may include determining a difference between the gage stiffness value and a baseline gage stiffness, wherein the difference is compared to a predetermined stiffness range. For example, the predetermined stiffness range may include a stiffness range that includes an expected change in measurement accuracy. The predetermined stiffness range may describe an amount of change in gage stiffness that is expected and not significant enough to generate a validation failure determination.

[0188] The predetermined stiffness range may be determined in any manner. In one embodiment, the predetermined stiffness range may include a predetermined tolerance range above and below the baseline gauge stiffness. Alternatively, the predetermined stiffness range may be derived from a standard deviation or confidence level determination that generates upper and lower range boundaries based on the baseline gauge stiffness, or other suitable processing techniques may be used to derive the predetermined stiffness range.

[0189] In step 509, a validation indication is generated because the difference between the meter stiffness value and the baseline meter stiffness falls within the predetermined stiffness range. Therefore, the meter stiffness is determined to have not changed significantly. No further action is required, however the results may be logged, reported, etc. The indication may include an indication to the user that the baseline meter stiffness is still valid. A successful validation indication means that the baseline meter stiffness is still accurate and useful, and the vibrating flow meter is still operating accurately and reliably.

[0190] In step 510, a validation failure indication is generated because the difference between the meter stiffness value and the baseline meter stiffness has exceeded a predetermined stiffness range. The stiffness of the meter is therefore determined to have changed significantly. As part of the non-validation indication, a software flag, visual indicator, message, alarm, or other indication may be generated to alert the user that the flow meter may not be as accurate and reliable as desired. In addition, the results may be logged, reported, and the like.

[0191] In step 511 , the difference between the gauge stiffness at the first pickoff sensor 170L and the second pickoff sensor 170R is calculated.

[0192] The resulting calculated difference in the gage stiffness values ​​of the first pickoff sensor 170L and the second pickoff sensor 170R is compared to the baseline gage stiffness difference in step 512. If the resulting calculated difference in the gage stiffness values ​​is within the predetermined stiffness difference range, the method branches to step 513. If the resulting calculated difference in the gage stiffness values ​​is not within the predetermined stiffness difference range, the method branches to step 514.

[0193] The comparison may include determining a difference between the resulting calculated gage stiffness value difference and a baseline gage stiffness difference value, wherein the difference is compared to a predetermined stiffness difference range. For example, the predetermined stiffness difference range may include a stiffness difference range that includes an expected change in measurement accuracy. The predetermined stiffness range may describe an amount of change in gage stiffness that is expected and not significant enough to generate a validation failure determination.

[0194] The predetermined stiffness difference range may be determined in any manner. In one embodiment, the predetermined stiffness difference range may include a predetermined tolerance range above and below the baseline gauge stiffness difference. Alternatively, the predetermined stiffness difference range may be derived from a standard deviation or confidence level determination that generates upper and lower range boundaries based on the baseline gauge stiffness difference, or other suitable processing techniques may be used to derive the predetermined stiffness difference range.

[0195] In step 513, a validation indication is generated because the difference between the resulting calculated meter stiffness value and the baseline meter stiffness difference falls within a predetermined stiffness difference range. Therefore, the meter stiffness is determined to have not changed significantly. No further action is required, although the results may be logged, reported, etc. The indication may include an indication to the user that the baseline meter stiffness difference is still valid. A successful validation indication means that the baseline meter stiffness difference is still accurate and useful, and the vibrating flow meter is still operating accurately and reliably.

[0196] In step 514, a validation failure indication is generated because the difference between the resulting calculated meter stiffness value and the baseline meter stiffness difference has exceeded a predetermined stiffness difference range. The stiffness of the meter is therefore determined to have changed significantly. As part of the non-validation indication, a software flag, visual indicator, message, alarm, or other indication may be generated to alert the user that the flow meter may not be as accurate and reliable as desired. In addition, the results may be logged, reported, and the like.

[0197] Figure 6 600 is a flow chart of a meter verification method for a vibrating flow meter according to an embodiment of the present invention. In step 601, a meter component of a vibrating flow meter is vibrated in a vibration mode to generate a single-mode vibration response. The single-mode vibration response includes electrical signals generated by a first pickoff sensor 170L and a second pickoff sensor 170R.

[0198] In step 602, a single mode current is determined as the current flowing through the driver 180. The current may include a command value of the current or may include a current value measured for the driver 190. In addition, a first response voltage and a second response voltage are determined at the first pickup sensor 170L and the second pickup sensor 170R, respectively. The first response voltage and the second response voltage are response voltages generated by the first pickup sensor and the second pickup sensor. The first response voltage and the second response voltage of the single mode may include voltages generated when operating at or near the resonant frequency of the single vibration mode.

[0199] In step 603 , a frequency response function (FRF) is generated for a first response voltage and a second response voltage determined according to the determined single mode current.

[0200] In step 604, the generated frequency response function is fit to the pole-residual-residual-flexure model described in the previous paragraph. The first order pole-residual-residual-flexure frequency response takes the form given in Equation 16. Further iterations are calculated according to Equations 14-16 and the related discussion thereof.

[0201] In step 605, the residual deflection value is compared to the baseline gage residual deflection. If the residual deflection value is within the predetermined residual deflection range, the method branches to step 606. If the residual deflection value is not within the predetermined residual deflection range, the method branches to step 607.

[0202] The comparison may include determining a difference between the residual deflection value and a baseline residual deflection, wherein the difference is compared to a predetermined residual deflection range. For example, the predetermined residual deflection range may include a residual deflection range that includes an expected change in measurement accuracy. The predetermined residual deflection range may describe an amount of change in residual deflection that is expected and not significant enough to generate a validation failure determination.

[0203] The predetermined residual deflection range may be determined in any manner. In one embodiment, the predetermined residual deflection range may include predetermined tolerances above and below the baseline gage residual deflection. Alternatively, the predetermined residual deflection range may be derived from a standard deviation or confidence level determination of generating upper and lower range boundaries from the baseline gage residual deflection, or other suitable processing techniques may be used to derive the predetermined residual deflection range.

[0204] In step 606, a validation indication is generated because the difference between the meter residual deflection value and the baseline meter residual deflection falls within the predetermined residual deflection range. Therefore, the meter residual deflection is determined to have not changed significantly. No further action is required, although the results may be logged, reported, etc. The indication may include an indication to the user that the baseline meter residual deflection is still valid. A successful validation indication means that the baseline meter residual deflection is still accurate and useful, and the vibrating flow meter is still operating accurately and reliably.

[0205] In step 607, a validation failure indication is generated because the difference between the meter residual deflection value and the baseline meter residual deflection has exceeded a predetermined residual deflection range. The residual deflection of the meter is therefore determined to have changed significantly. As part of the non-validation indication, a software flag, visual indicator, message, alarm, or other indication may be generated to alert the user that the flow meter may not be as accurate and reliable as desired. In addition, the results may be logged, reported, and the like.

[0206] In step 608 , the difference between the residual deflection values ​​at the first pickoff sensor 170L and the second pickoff sensor 170R is calculated.

[0207] The resulting calculated difference in residual deflection values ​​of the first pickoff sensor 170L and the second pickoff sensor 170R is compared to the baseline residual deflection difference in step 609. If the resulting calculated difference in residual deflection values ​​is within the predetermined residual deflection difference range, the method branches to step 610. If the resulting calculated difference in residual deflection values ​​is not within the predetermined residual deflection difference range, the method branches to step 611.

[0208] The comparison may include determining a difference between a resultant calculated gage residual deflection value and a baseline residual deflection difference, wherein the difference is compared to a predetermined residual deflection difference range. For example, the predetermined residual deflection difference range may include a residual deflection difference range that includes an expected change in measurement accuracy. The predetermined residual deflection difference range may describe an amount of change in residual deflection difference that is expected and not significant enough to generate a validation failure determination.

[0209] The predetermined residual deflection difference range may be determined in any manner. In one embodiment, the predetermined residual deflection difference range may include a predetermined tolerance range above and below the baseline residual deflection difference. Alternatively, the predetermined residual deflection difference range may be derived from a standard deviation or confidence level determination that generates upper and lower range boundaries based on the baseline residual deflection difference, or other suitable processing techniques may be used to derive the predetermined residual deflection range.

[0210] In step 610, a validation indication is generated because the difference between the resulting calculated meter residual deflection value and the baseline meter residual deflection difference falls within a predetermined residual deflection difference range. Therefore, the meter residual deflection is determined to have not changed significantly. No further action is required, however the result may be logged, reported, etc. The indication may include an indication to the user that the baseline residual deflection difference is still valid. A successful validation indication means that the baseline residual deflection is still accurate and useful, and the vibrating flow meter is still operating accurately and reliably.

[0211] In step 611, a validation failure indication is generated because the difference between the resulting calculated residual deflection value of the meter and the baseline residual deflection difference has exceeded a predetermined residual deflection difference range. The residual deflection difference of the meter is therefore determined to have changed significantly. As part of the non-validation indication, a software flag, visual indicator, message, alarm, or other indication may be generated to alert the user that the flow meter may not be as accurate and reliable as desired. In addition, the results may be logged, reported, and the like.

[0212] Figure 7700 is a flow chart of a meter verification method for a vibrating flow meter according to an embodiment of the present invention. In step 701, a meter component of a vibrating flow meter is vibrated in a vibration mode to generate a single-mode vibration response. The single-mode vibration response includes electrical signals generated by a first pickoff sensor 170L and a second pickoff sensor 170R.

[0213] In step 702, a single mode current is determined as a current flowing through the driver 180. The current may include a command value of the current or may include a current value measured for the driver 180. In addition, a first response voltage and a second response voltage are determined at the first pickup sensor 170L and the second pickup sensor 170R, respectively. The first response voltage and the second response voltage are response voltages generated by the first pickup sensor and the second pickup sensor. The first response voltage and the second response voltage of the single mode may include voltages generated when operating at or near the resonant frequency of the single vibration mode.

[0214] In step 703 , a frequency response function (FRF) is generated for a first response voltage and a second response voltage determined according to the determined single mode current.

[0215] In step 704, the generated frequency response function is fit to the pole-residue model described in the previous paragraph. The pole-residue frequency response takes the form given in Equation 13.

[0216] In step 705, a meter quality value is generated. Equation 10 is now used to generate the meter quality value.

[0217] In step 706, the expected mass deviation is calculated for the calculated first pickoff sensor 170L and the second pickoff sensor 170R using the fluid density (as explained in equations 21 and 22 and their related descriptions in the following paragraphs). In various aspects, the fluid density can include a measured process fluid density or alternatively an operator can input an expected fluid density.

[0218] In step 707, the calculated expected mass deviation is compared to the baseline expected mass deviation. If the calculated expected mass deviation is within the predetermined expected mass deviation range, the method branches to step 708. If the calculated mass deviation is not within the predetermined expected mass deviation range, the method branches to step 709.

[0219] The comparison may include determining the difference between the calculated expected mass deviation and the mass deviation expected from the baseline, wherein the difference is compared to a predetermined expected mass deviation range. For example, the predetermined expected mass deviation range may include an expected mass deviation range quality, which includes an expected change in measurement accuracy. The predetermined expected mass deviation value range may describe an amount of change in mass value that is expected and not significant enough to generate a validation failure determination.

[0220] The predetermined expected mass deviation range may be determined in any manner. In one embodiment, the predetermined expected mass deviation range may include predetermined tolerances above and below the baseline expected mass deviation values. Alternatively, the predetermined mass value range may be derived from a standard deviation or confidence level determination that generates upper and lower range boundaries based on the baseline meter expected mass deviation values, or other suitable processing techniques may be used to derive the predetermined mass value range.

[0221] In step 708, a validation indication is generated because the difference between the expected mass deviation and the baseline expected mass deviation falls within a predetermined expected mass deviation value range. Therefore, the expected mass deviation is determined to have not changed significantly. No further action is required, although the results may be logged, reported, etc. The indication may include an indication to the user that the baseline expected mass deviation is still valid. A successful validation indication means that the baseline expected mass deviation is still accurate and useful, and the vibrating flow meter is still operating accurately and reliably.

[0222] In step 709, a validation failure indication is generated because the difference between the expected mass deviation and the baseline expected mass deviation has exceeded a predetermined expected mass deviation range. The expected mass deviation of the meter is therefore determined to have changed significantly. As part of the non-validation indication, a software flag, visual indicator, message, alarm or other indication may be generated to alert the user that the flow meter may not be as accurate and reliable as desired. In addition, the results may be logged, reported, etc.

[0223] In step 710, the difference between the expected mass deviations at the first pickoff sensor 170L and the second pickoff sensor 170R is determined.

[0224] In step 711, the calculated difference in expected mass deviation is compared with the difference in expected mass deviation of the baseline. If the calculated difference in expected mass deviation is within the predetermined range of expected mass deviation differences, the method branches to step 712. If the calculated difference in expected mass deviation is not within the predetermined range of expected mass deviation differences, the method branches to step 713.

[0225] The comparison may include determining the difference between the difference of the expected mass deviation calculated as a result and the difference of the mass deviation expected from the baseline, wherein the difference is compared to a predetermined range of differences in the expected mass deviation. For example, the predetermined range of differences in the expected mass deviation may include a range of differences in the expected mass deviation that includes an expected change in measurement accuracy. The predetermined range of differences in the expected mass deviation may describe an amount of change in the mass value that is expected and not significant enough to generate a validation failure determination.

[0226] The predetermined range of differences in expected mass deviations may be determined in any manner. In one embodiment, the predetermined range of differences in expected mass deviations may include predetermined tolerances for mass deviations above and below the baseline expectation. Alternatively, the predetermined mass difference range may be derived from a standard deviation or confidence level determination that generates upper and lower range boundaries based on the difference in mass deviations expected from the baseline meter, or other suitable processing techniques may be used to derive the predetermined mass difference range.

[0227] In step 712, a validation indication is generated because the difference between the resultant calculated expected mass deviation difference and the baseline expected mass deviation difference falls within a predetermined expected mass deviation difference range. Therefore, the expected mass deviation difference is determined to have not changed significantly. No further action is required, although the result may be logged, reported, etc. The indication may include an indication to the user that the baseline expected mass deviation difference is still valid. A successful validation indication means that the baseline expected mass deviation difference is still accurate and useful, and the vibrating flow meter is still operating accurately and reliably.

[0228] In step 713, a validation failure indication is generated because the difference between the calculated difference in expected mass deviation and the difference in mass deviation expected by the baseline has exceeded a predetermined difference range in expected mass deviation. The difference in expected mass deviation of the meter is therefore determined to have changed significantly. As part of the non-validation indication, a software flag, visual indicator, message, alarm, or other indication may be generated to alert the user that the flow meter may not be as accurate and reliable as desired. In addition, the results may be logged, reported, or the like.

[0229] According to Figure 5 In the example embodiments described in, diagnostics using actual stiffness or the difference between the stiffness values ​​of the first pickoff sensor 170L and the second pickoff sensor 170R can be used as a flow meter validation parameter to determine coating, corrosion, erosion or other flow tube damage, as well as valid flow and density measurements.

[0230] Advantageously, diagnostics according to an embodiment utilize the inherent symmetry of Coriolis sensors. Smart Meter Verification (SMV) tracks stiffness at various locations over time and confirms their stability. If a meter is changing, existing production waits until the signal changes by 4% before flagging the operator. According to example embodiments, changes may be made to the sensor more rapidly than those known in the prior art.

[0231] Figure 8 Diagnostics according to an example embodiment are shown. Figure 8 , an example smart meter validation graph showing the percentage change in stiffness of the left pick-up (LPO) and right pick-up (RPO) sensors is shown. The y-axis represents the percentage value change in stiffness and the x-axis represents the run counter. The example SMV graph illustrates a baseline along with four corrosion conditions on the x-axis. The example data includes results from an example flow meter with both air and water as process fluids. According to the SMV graph, the data points corresponding to runs 1 through 6 are shown to have approximately zero percentage change in stiffness, which indicates the unchanging nature of this particular SMV diagnostic. However, as shown from the data points corresponding to runs 7 through 51, the impact on meter stiffness is clearly shown as the example flow meter is gradually corroded.

[0232] Fig. 9 Diagnostics according to an example embodiment are shown, using the difference between left pickup (LPO) and right pickup (RPO) stiffness data as a parameter. The y-axis represents the percent difference change in stiffness and the x-axis represents the run counter. Note that an offset is seen between the LPO and RPO, but the offset has very little change. The example graph illustrates a baseline along with four corrosion conditions on the x-axis. Figure 8 In confirmation, while the data points corresponding to runs 1 through 6 are shown as having approximately zero percent change in stiffness difference, the data points corresponding to runs 7 through 51 clearly show the effect on the meter stiffness difference as the example flow meter is progressively corroded.

[0233] according to Figure 6 In the example embodiment described in, a diagnostic implementing a meter verification method using the calculated difference in residual deflection of the first pickoff sensor 170L and the second pickoff sensor 170R can be used as a flow meter verification parameter to determine coating, corrosion, erosion or other flow tube damage.

[0234] Fig.10 Separate example model instances are shown for locations where meters are damaged by corrosion or erosion. Uniform corrosion on the example F300 flow meter is modeled as uniform changes in the pipe wall. Erosion on the F300 is modeled by locally changing the pipe wall in the inlet elbow area. Erosion on the example E300 is modeled by symmetrical changes in wall thickness at the elbow. Fig.11 A graph representing flow errors due to pipe wall erosion and / or corrosion is shown, where the percentage of flow calibration factor (FCF) error is plotted against the percentage of erosion and / or corrosion. Based on the graph, there is significant flow error due to these pipe wall changes. Fig.12 A graph showing the change in meter verification stiffness due to pipe wall erosion / corrosion is shown. It plots the change in meter verification stiffness versus flow calibration factor (FCF). From the graph, a large change in stiffness is seen for the two F300 conditions. Accordingly, the large change indicates that aspects of the present invention will easily detect F300 erosion and uniform corrosion. However, for a 12% FCF change, the stiffness change for the E300, which is more symmetrically eroded, is less than 1%, which may indicate poor detectability for this condition. Fig.13 Graphs showing the relationship of residual deflection (RF) change versus FCF change are shown. Residual deflection change can easily detect F300 erosion, but not F300 uniform corrosion. However, symmetrical erosion of E300 can be easily detected. Therefore, these graphs show how the combination of residual deflection and gage proof stiffness allows for robust diagnostics to detect erosion and corrosion. Fig.14 FIG. 2 shows a diagnosis of a difference between residual deflections of the first pickoff sensor 170L and the second pickoff sensor 170R according to an embodiment of the present invention. Fig.14 (Where the changes in the pipe wall are symmetrical, such as F300 corrosion and E300 erosion), the residual deflection difference may be very small. However, asymmetric F300 erosion shows large and significant values ​​for the residual deflection difference.

[0235] According to an example embodiment of the present invention, a simple difference in mass estimate between the first pickoff sensor 170L and the second pickoff sensor 170R may be used as a flow meter validation diagnostic parameter to determine coating, corrosion, erosion or other flow tube damage.

[0236] According to an example embodiment, Figure 7 As described in the , the diagnostic of the difference between the expected quality data of the first pickoff sensor 170L and the second pickoff sensor 170R can be used as a flow meter verification diagnostic parameter to determine coating, corrosion, erosion or other flow tube damage. Moreover, in combination with stiffness information (e.g., meter stiffness), the two diagnostics can distinguish between coating and erosion. In various aspects of the present invention, the quality estimate data diagnostic parameter utilizes the inherent symmetry of the Coriolis sensor and can be derived from the above-mentioned meter verification calculation.

[0237] Fig.15 Diagnostics according to an example embodiment are shown. Fig.15, an example smart meter validation graph showing the percentage change in mass deviation for left pick-up (LPO) and right pick-up (RPO) sensors is shown. The y-axis represents the percentage value change in mass deviation and the x-axis represents the run counter. The example SMV graph illustrates a baseline along with nine corrosion conditions on the x-axis. The example data includes results from an example flow meter with both air and water as process fluids. According to the SMV graph, the data points corresponding to runs 1 through 6 are shown to have approximately zero percent change in mass deviation, which indicates the unchanging nature of this particular SMV diagnostic. However, as shown from the data points corresponding to runs 7 through 51, the impact on mass deviation is clearly shown as the example flow meter is progressively corroded.

[0238] In embodiments, the process fluid density may be measured or input by an operator. When using process fluid density with mass estimation, two other coating detection parameters may be defined. In various aspects, the "expected" mass based on the plant baseline air and water mass and the measured known density of the process fluid may be calculated by the following equation:

[0239] (20).

[0240] Additionally, the expected mass can be used to calculate the normalized mass deviation expressed as a percentage via the following equation:

[0241] (twenty one).

[0242] Fig.16 1 shows a diagnostic according to an example embodiment that utilizes the difference between the left pick-up (LPO) mass deviation data and the right pick-up (RPO) mass deviation data as a parameter. The y-axis represents the percent difference change in mass deviation and the x-axis represents the run counter. Note that it is seen that there is an offset between the LPO and RPO, but the offset has very little change. The example graph illustrates a baseline along with four corrosion conditions on the x-axis. Fig.15 In confirmation, while the data points corresponding to runs 1 through 6 are shown as having approximately zero percent change in stiffness difference, the data points corresponding to runs 7 through 51 clearly show the impact of the difference in meter quality deviation as the example flow meter is progressively corroded.

[0243] According to an example embodiment of the present invention, density may be used as a flow meter validation diagnostic parameter to determine coating, corrosion, erosion or other flow tube damage.

[0244] Fig.17 Diagnostics according to an example embodiment are shown. Fig.17, an example smart meter validation graph represents the density of each run. The y-axis represents density and the x-axis represents the run counter. The example SMV density graph illustrates the baselines for air and water along with nine corrosion conditions on the x-axis. The baseline for air is shown in the data points corresponding to run 1. The baseline for water is shown in the data points corresponding to runs 2 through 6. The example data includes results resulting from an example flow meter that uses both air and water as process fluids. According to the example SMV density graph, the data points corresponding to runs 1 and 2 through 6 are shown to have approximately zero percent changes in density, which indicates the unchanging nature of this particular SMV diagnostic. However, as shown from the data points corresponding to runs 7 through 51, the impact on density is clearly shown as the example flow meter is gradually corroded.

[0245] Fig.18 Diagnostics according to an example embodiment are shown. Fig.18 , an example smart meter validation graph represents density for each run. The y-axis represents damping and the x-axis represents a run counter. The example SMV damping graph illustrates baselines for air and water along with nine corrosion conditions on the x-axis. The baseline for air is shown in the data points corresponding to run 1. The baseline for water is shown in the data points corresponding to runs 2 through 6. The example data includes results resulting from an example flow meter with both air and water as process fluids. According to the example SMV damping graph, the data points corresponding to runs 1 and 2 through 6 are shown to have approximately zero percent change in damping, with slight changes compared to the baseline, which indicates the unchanging nature of this particular SMV diagnostic. However, as shown from the data points corresponding to runs 7 through 51, the impact on damping is clearly shown as the example flow meter is gradually corroded.

[0246] In aspects of the invention, appropriate density alarm limits can be set to indicate coating. These alarm limits can be set dynamically based on the initial process density. In addition, according to aspects of the example embodiments, this parameter can be used to detect erosion. As an example, for an operator concerned about erosion, density can be tracked and an alarm can be triggered if the density reading drops below the expected limit due to material removal.

[0247] The above description provides a variety of methods for generating meter verification diagnostic parameters for a vibrating flow meter (5). According to embodiments of the present invention, deviations in flow meter parameters can be used to generate diagnostics, which can indicate coating, corrosion, erosion and / or flow tube damage. Each of the methods includes different advantages and the specific method employed can depend on the existing circumstances or equipment available. Some of the methods allow for detection of deviations in parameters in the absence of deviations in flow rate measurements. In addition, more than one method or all of the methods discussed above can be combined into a single flow meter system. Thus, the flow meter electronics 20 can compare detections obtained using one method with results obtained from another method.

[0248] The detailed description of the above embodiments is not an exhaustive description of all embodiments that the inventors contemplate within the scope of the present invention. Indeed, those skilled in the art will recognize that certain elements of the above embodiments may be variously combined or removed to create other embodiments, and such other embodiments fall within the scope and teachings of the present invention. It will also be apparent to those of ordinary skill in the art that the above embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the present invention.

[0249] Therefore, although specific embodiments of the invention and examples of the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention as will be appreciated by those skilled in the relevant art. The teachings provided herein may be applied to other flow meters, and not only to the embodiments described above and shown in the accompanying drawings. Accordingly, the scope of the invention should be determined from the following claims.

Claims

1. A vibrating flow meter (5) for meter verification, the vibrating flow meter (5) comprising: A flow meter assembly (10) comprising one or more flow tubes (130, 130') and first and second pickoff sensors (170L, 170R); a driver (180) configured to vibrate one or more flow tubes (130, 130'); as well as A meter electronics (20) coupled to first and second pickoff sensors (170L, 170R) and to a driver (180), wherein the meter electronics (20) is configured to: vibrate the flow meter assembly (10) in a single mode using the driver (180), determine a single mode current (230) of the driver (180), and determine first and second response voltages (231) generated by the first and second pickoff sensors (170L, 170R), respectively, according to calculating a frequency response function for the determined single mode current (230) with respect to the determined first and second response voltages (231), fitting the generated frequency response function to a pole residual model to calculate a meter stiffness value (216), calculating a difference in the meter stiffness values ​​at the first pickoff sensor and the second pickoff sensor (170L and 170R), and using the calculated difference in the meter stiffness values ​​to verify proper operation of the vibrating flow meter (5) to detect erosion, corrosion, or coating of the flow tube (130, 130'); wherein the meter stiffness value (216) comprises a stiffness correction for a measured fluid density calculated by the meter electronics (20).

2. The vibrating flow meter of claim 1, wherein the stiffness correction for the measured fluid density comprises calculating an expected stiffness.

3. The vibrating flow meter of claim 1, wherein the meter stiffness value (216) includes a correction for pressure.

4. The vibrating flow meter of claim 1 , wherein the verification of the vibrating flow meter using the meter stiffness value comprises: A difference between the gage stiffness value and a baseline gage stiffness is determined, and wherein the difference is compared to a predetermined stiffness range (219).

5. The vibrating flow meter of claim 1 , wherein the meter electronics (20) is further configured to compare the meter stiffness value (216) to a predetermined stiffness range (219), generate a validation indication for the vibrating flow meter (5) if the meter stiffness value (216) falls within the predetermined stiffness range (219), and generate a non-validation indication for the vibrating flow meter (5) if the meter stiffness value (216) does not fall within the predetermined stiffness range (219).

6. The vibrating flow meter of claim 1 , wherein a verification operation of the vibrating flow meter using the calculated difference in meter stiffness values ​​comprises: A difference between the calculated difference in gage stiffness values ​​and a baseline gage stiffness difference (224) is determined, and wherein the determined difference is compared to a predetermined stiffness difference range (225).

7. The vibrating flow meter of claim 1, wherein the meter electronics (20) is further configured to compare the calculated difference in meter stiffness values ​​to a predetermined stiffness difference range (225), generate a validation indication for the vibrating flow meter (5) if the calculated difference in meter stiffness values ​​falls within the predetermined stiffness difference range (225), and generate a non-validation indication for the vibrating flow meter (5) if the calculated difference in meter stiffness values ​​does not fall within the predetermined stiffness difference range (225).

8. A vibrating flow meter (5) for meter verification, the vibrating flow meter (5) comprising: A flow meter assembly (10) comprising one or more flow tubes (130, 130') and first and second pickoff sensors (170L, 170R); a driver (180) configured to vibrate one or more flow tubes (130, 130'); as well as A meter electronics (20) coupled to first and second pickoff sensors (170L, 170R) and to a driver (180), wherein the meter electronics (20) is configured to: vibrate the flow meter assembly (10) in a single mode using the driver (180), determine a single mode current (230) of the driver (180), and determine first and second response voltages (231) generated by the first and second pickoff sensors (170L, 170R), respectively, according to The determined single mode current (230) calculates a frequency response function for the determined first and second response voltages (231), fits the generated frequency response function to a pole residual model to calculate a meter quality value (240), calculates a difference in the meter quality values ​​at the first pickoff sensor and the second pickoff sensor (170L and 170R), and uses the calculated difference in the meter quality values ​​to verify proper operation of the vibrating flow meter (5) to detect erosion, corrosion, or coating of the flow tube (130, 130').

9. The vibrating flow meter of claim 8, wherein the verification operation of the vibrating flow meter using the calculated difference in meter quality values ​​comprises: A difference between the calculated difference in metrology quality values ​​and a baseline metrology quality difference (245) is determined, and wherein the determined difference is compared to a predetermined quality difference range (246).

10. The vibrating flow meter of claim 8, wherein the meter electronics (20) is further configured to compare the calculated difference in meter mass values ​​to a predetermined mass difference range (246), generate a validation indication for the vibrating flow meter (5) if the calculated difference in meter mass values ​​falls within the predetermined mass difference range (246), and generate a non-validation indication for the vibrating flow meter (5) if the calculated difference in meter mass values ​​does not fall within the predetermined mass difference range (246).

11. The vibrating flow meter of claim 8, wherein the meter electronics (20) is further configured to calculate an expected mass deviation (250) for the first and second pickoff sensors (170L and 170R) using the measured fluid density, and to use the expected mass deviation (250) to verify proper operation of the vibrating flow meter (5).

12. The vibrating flow meter of claim 11, wherein the meter electronics (20) is further configured to calculate a difference in expected mass deviation values ​​at the first pickoff sensor and the second pickoff sensor (170L and 170R), and to use the calculated difference in expected mass deviation values ​​to verify proper operation of the vibrating flow meter (5).

13. The vibrating flow meter of claim 12, wherein a validation operation of the vibrating flow meter using the calculated difference in expected mass deviation values ​​comprises: A difference between the calculated expected mass deviation mass value difference and the baseline expected mass deviation difference (255) is determined, and wherein the determined difference is compared to a predetermined expected mass deviation difference range (256).

14. The vibrating flow meter of claim 12, wherein the meter electronics (20) is further configured to compare the calculated difference in expected mass deviation values ​​to a predetermined difference range (256) for expected mass deviations, generate a validation indication for the vibrating flow meter (5) if the calculated difference in expected mass deviation values ​​falls within the predetermined difference range (256) for expected mass deviations, and generate a non-validation indication for the vibrating flow meter (5) if the calculated difference in expected mass deviation values ​​does not fall within the predetermined difference range (256) for expected mass deviations.

15. A meter verification method for a vibrating flow meter, wherein the method comprises: Using a driver to vibrate a flow meter component of the vibrating flow meter in a single mode; determining a single-mode current of the driver and determining first and second single-mode response voltages generated by the first pickoff sensor and the second pickoff sensor, respectively; calculating a frequency response function for the determined first and second response voltages based on the determined single mode current; fitting the generated frequency response function to a pole residual model to generate a gauge stiffness value (216); calculating a difference in meter stiffness values ​​at a first pickoff sensor and a second pickoff sensor (170L and 170R), and using the calculated difference in meter stiffness values ​​to verify proper operation of a vibrating flow meter (5) to detect erosion, corrosion, or coating of a flow tube (130, 130') included in the flow meter assembly; wherein the meter stiffness value (216) comprises a stiffness correction for a measured fluid density calculated by the meter electronics (20).

16. The meter validation method of claim 15, wherein the stiffness correction of the measured fluid density comprises calculating an expected stiffness.

17. The gage validation method of claim 15, wherein the gage stiffness value (216) includes a correction for pressure.

18. The meter verification method of claim 15, wherein the verification operation of the vibrating flow meter using the meter stiffness value comprises: A difference between the gage stiffness value and a baseline gage stiffness is determined, and wherein the difference is compared to a predetermined stiffness range (219).

19. The meter verification method of claim 15, further comprising: The meter stiffness value (216) is compared to a predetermined stiffness range (219), a validation indication is generated for the vibrating flow meter (5) if the meter stiffness value (216) falls within the predetermined stiffness range (219), and a non-validation indication is generated for the vibrating flow meter (5) if the meter stiffness value (216) does not fall within the predetermined stiffness range (219).

20. The meter verification method of claim 15, wherein verification of the vibrating flow meter using the calculated difference in meter stiffness values ​​comprises: A difference between the calculated difference in gage stiffness values ​​and a baseline gage stiffness difference (224) is determined, and wherein the determined difference is compared to a predetermined stiffness difference range (225).

21. The meter verification method of claim 15, further comprising: The calculated difference in meter stiffness values ​​is compared to a predetermined stiffness difference range (225), a validation indication is generated for the vibrating flow meter (5) if the calculated difference in meter stiffness values ​​falls within the predetermined stiffness difference range (225), and a non-validation indication is generated for the vibrating flow meter (5) if the calculated difference in meter stiffness values ​​does not fall within the predetermined stiffness difference range (225).

22. A meter verification method for a vibrating flow meter, wherein the method comprises: Using a driver to vibrate a flow meter component of the vibrating flow meter in a single mode; determining a single mode current of the driver and determining first and second single mode response voltages generated by the first and second pickoff sensors, respectively; calculating a frequency response function for the determined first and second response voltages based on the determined single mode current; fitting the generated frequency response function to a pole residual model to generate a meter quality value (240); A difference in meter mass values ​​at a first pickoff sensor and a second pickoff sensor (170L and 170R) is calculated, and the calculated difference in meter mass values ​​is used to verify proper operation of a vibrating flow meter (5) to detect erosion, corrosion, or coating of a flow tube (130, 130') included in the flow meter assembly.

23. The meter verification method of claim 22, wherein verification of the vibrating flow meter using the calculated difference in meter quality values ​​comprises: A difference between the calculated difference in metrology quality values ​​and a baseline metrology quality difference (245) is determined, and wherein the determined difference is compared to a predetermined quality difference range (246).

24. The meter verification method of claim 22, further comprising: The calculated difference in meter mass values ​​is compared to a predetermined mass difference range (246), a validation indication is generated for the vibrating flow meter (5) if the calculated difference in meter mass values ​​falls within the predetermined mass difference range (246), and a non-validation indication is generated for the vibrating flow meter (5) if the calculated difference in meter mass values ​​does not fall within the predetermined mass difference range (246).

25. The meter verification method of claim 22, further comprising: The measured fluid density is used to calculate an expected mass deviation (250) for the first and second pickoff sensors (170L and 170R), and the expected mass deviation (250) is used to verify proper operation of the vibrating flow meter (5).

26. The meter verification method of claim 25, further comprising: A difference in expected mass deviation values ​​at the first pickoff sensor and the second pickoff sensor (170L and 170R) is calculated, and the calculated difference in expected mass deviation values ​​is used to verify proper operation of the vibrating flow meter (5).

27. The meter verification method of claim 26, wherein verification of the vibrating flow meter using the calculated difference in expected mass deviation values ​​comprises: A difference between the calculated expected mass deviation mass value difference and the baseline expected mass deviation difference (255) is determined, and wherein the determined difference is compared to a predetermined expected mass deviation difference range (256).

28. The meter verification method of claim 26, further comprising: The calculated difference in expected mass deviation values ​​is compared to a predetermined expected mass deviation difference range (256), a validation indication is generated for the vibrating flow meter (5) if the calculated difference in expected mass deviation values ​​falls within the predetermined expected mass deviation difference range (256), and a non-validation indication is generated for the vibrating flow meter (5) if the calculated difference in expected mass deviation values ​​does not fall within the predetermined expected mass deviation difference range (256).

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