Determining and using mass flow rate error correction relationships in vibratory flow meters

Abstract

A method for determining a mass flow rate error correction relationship is provided. The method includes comparing each of the plurality of mass flow rate measurements of the alternative gas stream with a corresponding each of the plurality of reference mass flow rate measurements of the alternative gas stream. The method further includes determining a plurality of mass flow rate measurement errors corresponding to the plurality of fluid velocity related parameter values of the alternative gas flow based on the comparison.

Description

Technical Field

[0001] The embodiments described below relate to correcting mass flow rate of a vibrating meter, and more particularly, to determining and using a mass flow rate error correction relationship for a vibrating meter. Background Art

[0002] Vibrating meters, such as Coriolis mass flow meters, liquid density meters, gas density meters, liquid viscosity meters, gas / liquid specific gravity meters, gas / liquid relative density meters, and gas molecular weight meters, are generally known and used to measure properties of fluids. Typically, a vibrating meter includes a sensor assembly and meter electronics. The material in or around the sensor assembly may be flowing or stationary. A vibrating meter may be used to measure mass flow rate, density, or other properties of the material in the sensor assembly.

[0003] For example, a Coriolis flow meter can measure mass flow rate. For example, a Coriolis flow meter can provide a drive signal to a driver disposed between two parallel and balanced conduits that contain a fluid flowing through the conduits. The driver causes out-of-phase vibrations between the two conduits. The fluid flowing through the two conduits causes a phase difference between the inlet and outlet of the two conduits. The phase difference is measured by two pick-off sensors located on either side of the midpoint of the two conduits. For example, one of the two pick-off sensors can be close to the inlet of the two conduits, while the other can be close to the outlet of the two conduits. The measured phase difference is scaled by a flow calibration factor to obtain a mass flow rate measurement. When measuring a gas, the mass flow rate measurement typically includes an error associated with the mass flow rate of the gas, which can be referred to as a mass flow rate measurement error.

[0004] Therefore, calibration of a Coriolis flow meter for measuring a gas flow typically includes determining a mass flow rate measurement error based on the mass flow rate. For example, a reference Coriolis flow meter connected in series with a calibrated Coriolis flow meter can provide a known mass flow rate measurement value of the gas flow. The known mass flow rate measurement value of the gas flow can be compared with the uncorrected mass flow rate measurement value provided by the calibrated Coriolis flow meter to determine the mass flow rate measurement error. This comparison to determine the mass flow rate measurement error can be performed at various mass flow rates of the gas flow to obtain pairs (e.g., ordered pairs) of mass flow rate measurement error values ​​and mass flow rate values. These pairs can be used to correct subsequent uncorrected mass flow rate measurements obtained by the Coriolis flow meter.

[0005] As can be appreciated, process gases may not be available for calibrating Coriolis flow meters. Therefore, surrogate gases have been used to calibrate Coriolis flow meters. The density of the surrogate gas is typically different from the density of the process gas. This density difference can cause deviations in mass flow rate measurement errors between different gases at a given flow rate. In order to reduce the effect of density on mass flow rate measurement errors, the pressure of the surrogate gas is adjusted until the density of the surrogate gas is approximately the same as the density of the process gas whose mass flow rate measurement is to be corrected.

[0006] However, one or more characteristics other than density may result in a deviation between the mass flow rate measurement errors of the surrogate gas flow and the process gas flow. Thus, if the deviation is large enough, the mass flow rate measurement error of the surrogate gas flow may not necessarily transfer to correct the mass flow rate measurement error of the process gas flow. Therefore, it is necessary to determine and use a mass flow rate error correction relationship for a vibrating meter. Summary of the invention

[0007] A method for determining mass flow rate error correction values ​​for a vibrating meter is provided. According to an embodiment, the method includes comparing each of a plurality of mass flow rate measurements of a surrogate gas flow with a corresponding each of a plurality of reference mass flow rate measurements of the surrogate gas flow, and determining a plurality of mass flow rate measurement errors corresponding to a plurality of fluid velocity related parameter values ​​of the surrogate gas flow based on the comparison.

[0008] A system for determining a mass flow rate error correction relationship for a vibrating meter is provided. According to an embodiment, the system includes: a vibrating meter configured to measure the mass flow rate of a surrogate gas flow; a reference device connected in series with the vibrating meter, the reference device configured to determine a reference mass flow rate of the surrogate gas flow; and a calibration circuit in communication with the vibrating meter and the reference device, the calibration circuit configured to perform the aforementioned method.

[0009] A method for using a mass flow rate error correction relationship for a vibrating meter is provided. According to an embodiment, the method includes determining a fluid velocity related parameter value for a process gas flow based on a measured mass flow rate value, a density value, and a cross-sectional area of ​​the process gas flow, and determining a mass flow rate error correction value based on the fluid velocity related parameter value.

[0010] A meter electronics device for using a mass flow rate error correction relationship is provided. According to an embodiment, the meter electronics device includes a storage system and a processing system communicatively coupled to the storage system, the processing system configured to perform the aforementioned method.

[0011] A vibrating meter for using a mass flow rate error correction relationship is provided. According to an embodiment, the vibrating meter includes a sensor assembly configured to measure the mass flow rate of a process gas flow and meter electronics communicatively coupled to the sensor assembly, the meter electronics provided in accordance with the foregoing.

[0012] aspect

[0013] According to one aspect, a method of determining mass flow rate error correction values ​​for a vibrating meter includes comparing each of a plurality of mass flow rate measurements of a surrogate gas flow to a corresponding each of a plurality of reference mass flow rate measurements of the surrogate gas flow, and determining a plurality of mass flow rate measurement errors corresponding to a plurality of fluid velocity-related parameter values ​​of the surrogate gas flow based on the comparison.

[0014] Preferably, the plurality of fluid velocity related parameter values ​​of the surrogate gas flow comprises one of a plurality of fluid velocity values ​​and a plurality of Mach numbers of the surrogate gas flow.

[0015] Preferably, a plurality of reference mass flow rate measurements of the surrogate gas flow are provided by a reference device connected in series with the vibrating meter.

[0016] Preferably, the replacement gas stream comprises one of air, natural gas, carbon dioxide, nitrogen and helium.

[0017] Preferably, the plurality of mass flow rate measurement errors corresponding to the plurality of fluid velocity related parameter values ​​of the surrogate gas flow comprises a plurality of differences between each of the plurality of mass flow rate measurements and a corresponding each of the plurality of reference mass flow rate measurements.

[0018] Preferably, the method further comprises flowing a flow of replacement gas through the vibrating meter.

[0019] Preferably, the method further comprises determining, using the vibrating meter, a plurality of mass flow rate measurements at a corresponding plurality of fluid velocity related parameter values ​​of the surrogate gas flow.

[0020] Preferably, the method further comprises storing the plurality of mass flow rate measurement errors as a plurality of ordered pairs of the plurality of mass flow rate measurement errors and the corresponding plurality of fluid velocity related parameter values ​​in meter electronics of the vibrating meter.

[0021] Preferably, the method further comprises determining a mass flow rate error correction relationship based on the plurality of mass flow rate measurement errors and the corresponding plurality of fluid velocity related parameter values, and storing the mass flow rate error correction relationship in the vibrating meter.

[0022] According to one aspect, a system for determining a mass flow rate error correction relationship for a vibrating meter includes: a vibrating meter configured to measure a mass flow rate of a surrogate gas flow; a reference device connected in series with the vibrating meter, the reference device configured to determine a reference mass flow rate of the surrogate gas flow; and calibration circuitry in communication with the vibrating meter and the reference device, the calibration circuitry configured to perform the above method.

[0023] According to one aspect, a method for using a mass flow rate error correction relationship for a vibrating meter includes: determining a fluid velocity related parameter value for a process gas flow based on a measured mass flow rate value, a density value, and a cross-sectional area of ​​the process gas flow; and determining a mass flow rate error correction value based on the fluid velocity related parameter value.

[0024] Preferably, the fluid velocity related parameter value comprises one of a fluid velocity value and a Mach number value of the process gas flow.

[0025] Preferably, the process gas stream is a hydrogen stream.

[0026] Preferably, the method further comprises measuring the mass flow rate of the process gas stream using a vibrating meter to determine a measured mass flow rate value.

[0027] Preferably, the method further comprises correcting the measured mass flow rate value using a mass flow rate error correction value.

[0028] Preferably, determining the mass flow rate error correction value based on the fluid velocity related parameter value comprises obtaining a mass flow rate error correction relationship for the surrogate gas flow, and determining the mass flow rate correction value based on the mass flow rate error correction relationship for the surrogate gas flow and the fluid velocity related parameter value.

[0029] Preferably, the replacement gas stream comprises one of air, natural gas, carbon dioxide, nitrogen and helium.

[0030] According to one aspect, meter electronics for using a mass flow rate error correction relationship includes a storage system and a processing system communicatively coupled to the storage system, the processing system configured to perform the aforementioned method.

[0031] According to one aspect, a vibrating meter for using a mass flow rate error correction relationship includes a sensor assembly configured to measure mass flow rate of a process gas flow and meter electronics communicatively coupled to the sensor assembly, the meter electronics provided in accordance with the foregoing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Like reference numerals represent like elements throughout the drawings. It should be understood that the drawings are not necessarily drawn to scale.

[0033] Figure 1A vibrating meter 5 configured to determine and use a mass flow rate error correction relationship for the vibrating meter 5 is shown.

[0034] Figure 2 A block diagram of a vibrating meter 5 including a block diagram representation of meter electronics 20 configured to determine and use a mass flow rate error correction value for the vibrating meter 5 is shown.

[0035] Figure 3 Meter electronics 20 for determining and using a mass flow rate error compensation relationship for a vibrating meter 5 is shown.

[0036] Figure 4 A graph 400 illustrating the lack of a discernible relationship between mass flow rate error percentage and mass flow rate is shown.

[0037] Figure 5 A graph 500 illustrating a discernible relationship between mass flow rate error percentage and a fluid velocity related parameter is shown.

[0038] Figure 6 A graph 600 illustrating a discernible relationship between mass flow rate error percentage and a fluid velocity related parameter is shown.

[0039] Figure 7 A graph 700 illustrating the lack of a discernible relationship between mass flow rate error percentage and mass flow rate is shown.

[0040] Figure 8 A graph 800 illustrating a discernible relationship between mass flow rate error percentage and a fluid velocity related parameter is shown.

[0041] Fig. 9 A graph 900 illustrating a discernible relationship between mass flow rate error percentage and a fluid velocity related parameter after a mass flow rate error correction relationship has been applied is shown.

[0042] Fig.10 A system 1000 for determining a mass flow rate error correction relationship for a vibrating meter is shown.

[0043] Fig.11 A method 1100 of determining a mass flow rate error correction relationship for a vibrating meter, such as the vibrating meter 5 described above, is shown.

[0044] Fig.12 A method 1200 of using a mass flow rate error correction relationship for a vibrating meter, such as the vibrating meter 5 described above, is shown. DETAILED DESCRIPTION

[0045] Figures 1 to 12The following description depicts specific examples to teach those skilled in the art how to make and use the best mode of implementation of determining and using the mass flow rate error correction relationship for the vibrating meter. In order to teach the principles of the invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand variations of these examples that fall within the scope of this specification. Those skilled in the art will understand that the features described below can be combined in various ways to form multiple variations of determining and using the mass flow rate error correction relationship for the vibrating meter. Therefore, the embodiments described below are not limited to the specific examples described below, but are limited only by the claims and their equivalents.

[0046] Figure 1 A vibrating meter 5 is shown that is configured to determine and use a mass flow rate error correction relationship for the vibrating meter 5. Figure 1 As shown, the vibrating meter 5 is a Coriolis flow meter including a sensor assembly 10 and a meter electronics 20. The sensor assembly 10 is responsive to the mass flow rate and density of the process material. The meter electronics 20 is connected to the sensor assembly 10 via leads 100 to provide density, mass flow rate and temperature information through a port 26, as well as other information.

[0047] The sensor assembly 10 includes a pair of manifolds 150 and 150', flanges 103 and 103' having flange necks 110 and 110', a pair of parallel conduits 130 and 130', a driver 180, a resistance temperature detector (RTD) 190, and a pair of pick-off sensors 170l and 170r. The conduits 130 and 130' have two substantially straight inlet branches 131, 131' and outlet branches 134, 134' that converge toward each other at conduit mounting blocks 120 and 120'. The conduits 130, 130' are bent at two symmetrical locations along their lengths and are substantially parallel throughout their lengths. The braces 140 and 140' are used to define axes W and W' about which each conduit 130, 130' oscillates. The branches 131, 131' and 134, 134' of the conduits 130, 130' are fixedly attached to the conduit mounting blocks 120 and 120', which in turn are fixedly attached to the manifolds 150 and 150'. This provides a continuous closed material path through the sensor assembly 10.

[0048] When flange 103 with hole 102 and flange 103' with hole 102' are connected to a process line (not shown) carrying process material to be measured via inlet port 104 and outlet port 104', the material enters the inlet port 104 of the vibrating meter through the orifice 101 in flange 103 and is conducted through manifold 150 to conduit mounting block 120 with surface 121. Within manifold 150, the material is separated and directed through conduits 130, 130'. Upon exiting conduits 130, 130', the process material is recombined into a single stream within block 120' with surface 121' and manifold 150' and is then directed to outlet port 104' connected to a process line (not shown) through flange 103' with hole 102'.

[0049] The conduits 130, 130' are selected and appropriately mounted to the conduit mounting blocks 120, 120' so as to have substantially the same mass distribution, moment of inertia and Young's modulus about the bending axes W--W and W'--W', respectively. These bending axes pass through the struts 140, 140'. Since the Young's modulus of the conduit varies with temperature, and this variation can affect the calculation of flow and density, an RTD 190 is mounted to the conduit 130' to continuously measure the temperature of the conduit 130'. The temperature of the conduit 130' and therefore the voltage appearing across the RTD 190 due to a given current passing through the RTD 190 is controlled by the temperature of the material passing through the conduit 130'. The temperature-dependent voltage appearing across the RTD 190 is used by the meter electronics 20 in a known manner to compensate for changes in the elastic modulus of the conduits 130, 130' due to any changes in the temperature of the conduits. The RTD 190 is connected to the meter electronics 20 by leads 195.

[0050] Both conduits 130, 130' are driven by a driver 180 about their respective bending axes W and W' in opposite directions and in what is referred to as the first out-of-phase bending mode of the vibrating meter. The driver 180 may include any of a number of well-known devices, such as a magnet mounted on the conduit 130' and an opposing coil mounted to the conduit 130 and through which an alternating current is passed to vibrate both conduits 130, 130'. A suitable drive signal 185 is applied to the driver 180 by the meter electronics 20 via leads.

[0051] Meter electronics 20 receives the RTD temperature signal 190 on the leads, and the sensor signal 165 present on leads 100 carrying left and right sensor signals 1651, 165r, respectively. Meter electronics 20 generates a drive signal 185 present on the leads to driver 180 and causes conduits 130, 130' to vibrate. Meter electronics 20 processes the left and right sensor signals 1651, 165r and the RTD signal 190 to calculate the mass flow rate and density of the material passing through the sensor assembly 10. This information is applied by meter electronics 20 along with other information as a signal to path 26. Meter electronics 20 will be discussed in more detail below.

[0052] Figure 2 1 shows a block diagram of a vibrating meter 5 including a block diagram representation of meter electronics 20 configured to determine and use a mass flow rate error correction value for the vibrating meter 5. Figure 2 As shown, meter electronics 20 is communicatively coupled to sensor assembly 10. As described above with reference to Figure 1 As shown, the sensor assembly 10 includes left and right pickoff sensors 1701 , 170 r , a driver 180 , and a temperature sensor 190 , which are communicatively coupled to the meter electronics 20 via a set of leads 100 through a communication channel 112 .

[0053] The meter electronics 20 provides the drive signal 185 via the lead 100. More specifically, the meter electronics 20 provides the drive signal 185 to the driver 180 in the sensor assembly 10. In addition, the sensor signals 165, including the left sensor signal 1651 and the right sensor signal 165r, are provided by the sensor assembly 10. More specifically, in the illustrated embodiment, the sensor signals 165 are provided by the left pickoff sensor 1701 and the right pickoff sensor 170r in the sensor assembly 10. As can be appreciated, the sensor signals 165 are provided to the meter electronics 20 separately via the communication channel 112.

[0054] The meter electronics 20 includes a processor 210 communicatively coupled to one or more signal processors 220 and one or more memories 230. The processor 210 is also communicatively coupled to the user interface 30. The processor 210 is communicatively coupled to the host via a communication port on the port 26 and receives power via a power port 250. The processor 210 can be a microprocessor, but any suitable processor can be used. For example, the processor 210 can include sub-processors (e.g., a multi-core processor), a serial communication port, a peripheral interface (e.g., a serial peripheral interface), on-chip memory, I / O ports, etc. In these and other embodiments, the processor 210 is configured to perform operations on received and processed signals (e.g., digitized signals).

[0055] The processor 210 may receive digitized sensor signals from one or more signal processors 220. The processor 210 is also configured to provide information such as phase difference, characteristics of the fluid in the sensor assembly 10, etc. The processor 210 may provide information to the host through a communication port. The processor 210 may also be configured to communicate with one or more memories 230 to receive information and / or store information in one or more memories 230. For example, the processor 210 may receive calibration factors, sensor assembly zero points (e.g., phase difference when the flow rate is zero), and mass flow rate correction values ​​from one or more memories 230. Each of the calibration factors, sensor assembly zero points, and mass flow rate correction values ​​may be associated with the vibrating meter 5 and / or the sensor assembly 10, respectively. The processor 210 may use the calibration factors and / or sensor assembly zero points to process the digitized sensor signals received from one or more signal processors 220 to determine a process value, such as density or mass flow rate. The processor 210 may also use the mass flow rate correction value to correct the mass flow rate determined from the digitized sensor signal.

[0056] The one or more signal processors 220 are shown to include a coder / decoder (CODEC) 222 and an analog-to-digital converter (ADC) 226. The one or more signal processors 220 can condition analog signals, digitize conditioned analog signals, and / or provide digitized signals. The CODEC 222 is configured to receive sensor signals 165 from the left and right pickup sensors 170l, 170r. The CODEC 222 is also configured to provide a drive signal 185 to the driver 180. In alternative embodiments, more or fewer signal processors may be employed.

[0057] As shown, the sensor signal 165 is provided to the CODEC 222 via the signal conditioner 240. The drive signal 185 is provided to the driver 180 via the signal conditioner 240. Although the signal conditioner 240 is shown as a single block, the signal conditioner 240 may include signal conditioning components (e.g., two or more operational amplifiers), filters (e.g., low-pass filters), voltage-current amplifiers, etc. For example, the sensor signal 165 may be amplified by a first amplifier, and the drive signal 185 may be amplified by a voltage-current amplifier. Amplification may ensure that the amplitude of the sensor signal 165 is close to the full-scale range of the CODEC 222.

[0058] In the illustrated embodiment, the one or more memories 230 include a read-only memory (ROM) 232, a random access memory (RAM) 234, and a ferroelectric random access memory (FRAM) 236. However, in alternative embodiments, the one or more memories 230 may include more or less memories. Additionally or alternatively, the one or more memories 230 may include different types of memories (e.g., volatile, non-volatile, etc.). For example, different types of non-volatile memories, such as erasable programmable read-only memory (EPROM), etc., may be used in place of the FRAM 236. The one or more memories 230 may be memories configured to store process data (e.g., drive or sensor signals, mass flow rate or density measurements, etc.).

[0059] The mass flow rate measurement can be generated according to the following equation:

[0060]

[0061] in:

[0062] is the measured mass flow rate;

[0063] FCF is the flow calibration factor;

[0064] Δt is the measured time delay; and

[0065] Δt 0 is the zero flow time delay.

[0066] The measured time delay Δt includes an operationally derived (i.e., measured) time delay value that includes a time delay between pick-off sensor signals, e.g., a time delay due to the Coriolis effect associated with the mass flow rate through the vibrating meter 5. The measured time delay Δt is a direct measure of the mass flow rate of the flowing material as it flows through the vibrating meter 5. Zero flow time delay Δt 0 Includes time delay at zero flow. Zero flow time delay Δt 0 is the zero flow value that can be determined at the factory and programmed into the vibrating meter 5. Zero flow time delay Δt 0 is an exemplary zero flow value. Other zero flow values ​​determined under zero flow conditions may be used, such as phase difference, time difference, etc. Even if flow conditions change, the zero flow time delay Δt 0 The value of may not change. By comparing the measured time delay Δt with the reference zero flow value Δt 0 The difference between is multiplied by the flow calibration factor FCF to determine the mass flow rate value of the material flowing through the vibrating meter 5. The flow calibration factor FCF is proportional to the physical stiffness of the vibrating meter.

[0067] As for density, the resonant frequency at which each conduit 130, 130' may vibrate may be a function of the square root of the spring constant of the conduit 130, 130' divided by the total mass of the conduit 130, 130' with material. The total mass of the conduit 130, 130' with material may be the mass of the conduit 130, 130' plus the mass of the material within the conduit 130, 130'. The mass of the material in the conduit 130, 130' is proportional to the density of the material. Thus, the density of the material may be proportional to the square of the period of oscillation of the conduit 130, 130' containing the material multiplied by the spring constant of the conduit 130, 130'. Thus, by determining the period of oscillation of the conduit 130, 130' and appropriately scaling the result, an accurate measurement of the density of the material contained by the conduit 130, 130' may be obtained. The meter electronics 20 may determine the period or resonant frequency using the sensor signal 165 and / or the drive signal 185. The conduit 130, 130' may oscillate in more than one vibration mode.

[0068] When the vibrating meter 5 is in a no-flow or zero-flow condition, the vibrating meter 5 can be calibrated using the factory zero-flow value. At any time, the user can additionally and optionally perform a push-button calibration to obtain a push-button zero-flow value. Additionally or alternatively, the vibrating meter can automatically perform a calibration to obtain an automatic zero-flow value. The zero-flow value used to measure the flow rate of the fluid can be a factory zero-flow value, a push-button zero-flow value, an automatic zero-flow value, or any other suitable zero-flow value.

[0069] During zero calibration of the vibrating meter 5, measured values, saved values / constants, user settings, saved tables, etc. may be used. Calibration may monitor vibrating meter 5 conditions for the vibrating meter 5 and compensate for those conditions. The conditions may include, but are not limited to, user-entered conditions, measured conditions, inferred conditions, etc. These conditions may include temperature, fluid density, flow rate, meter specifications, viscosity, Reynolds number, post-calibration compensation, etc. In addition, different constants, such as, but not limited to, flow calibration factors (FCFs), may be applied based on operating conditions or user preferences.

[0070] The initial zero flow value may be determined during calibration performed as part of the initial factory setup of the vibrating meter 5. This may require placing the vibrating meter 5 in a no-flow or zero-flow condition and determining a time delay, phase difference, etc. between the left sensor signal 165l and the right sensor signal 165r. The determined value is stored in one or more memories 230 as the initial zero flow value and used as a reference zero flow value. For example, for equation [1] discussed above, the reference zero flow value may be ΔT 0Term, which can be the no-flow time delay or zero-flow time delay between the left sensor signal 165l and the right sensor signal 165r. Once the reference zero-flow value is determined, a flow calibration factor (FCF) can be established. As can be understood from the above equation [1], the flow calibration factor can be the time delay Δt indicating the measurement 测量的 With mass flow rate The FCF may be stored in one or more memories 230 .

[0071] Correction of the measured mass flow rate of the process gas stream

[0072] When testing vibrating meters (e.g. Coriolis meters) in a gas lab, the exact gas and process conditions of the final application cannot always be replicated. Historically, vibrating meters for gas flow applications have attempted to use equivalent flowing gas density or Reynolds number or mass-based comparisons. While these can be useful techniques for other technologies (e.g. orifice meters), it is not always the best basis of comparison for vibrating meters. In order to establish a common basis of comparison between the test gas conditions and the application conditions in order to linearize the meter adjustments for optimal measurement accuracy over a range of flow rates, the linearization correction value function can be described using Mach number as an input value. Alternatively, in cases where the molecular weight, speed of sound, and chemical composition of the gas are not completely known, the fluid velocity can be used as a function input.

[0073] As long as the gases to be measured have similar properties, the gas measurement accuracy of the vibrating meter can be optimized by defining a linearization curve based on mass flow rate as input variable. When gases that may have very different densities may be measured later, the best measurement can be achieved by linearizing the meter with a calibration curve that has velocity as input variable. In addition, the best measurement can be achieved by linearizing the meter using a calibration curve with Mach number as input variable, because the Mach number takes into account the gas velocity as well as the molecular weight of the gas. These combined parameters can better predict the flow conditions that affect the measurement accuracy of the vibrating meter.

[0074] Vibrating meters are directly affected by flow noise and other conditions that are uniquely different in association with gas flows than with liquid flows. For example, broad-based white noise and other effects that occur simply because of the compressibility of gas phase flow streams interfere with the basic measurement signal and can degrade the measurement quality in a way that causes greater nonlinearity over a range of flow rates than is typically seen in liquid flows. The severity of this effect can be directly tracked with the Mach number as determined by the velocity of the gas in the flow tube. Some evidence of performance degradation (decreased accuracy and repeatability) can be observed when flow tube velocities exceed Mach 0.2, while performance can be significantly degraded when flow tube velocities exceed Mach 0.3.

[0075] Typical compensation schemes for vibrating meters either apply corrections using a single meter coefficient (e.g., a flow-weighted average as described in AGA Report No. 11) under all flow conditions, or apply a variable correction based on mass flow rate (i.e., a linearized correction curve). Calibration curves or data based on mass flow rate are not easily transferable between gases of different composition and / or density because mass rates can vary significantly as process conditions vary between gas types and densities. For example, nonlinearities observed in a natural gas testing laboratory are less likely to be replicated in a hydrogen measurement application as a function of mass flow rate than as a function of velocity or Mach number.

[0076] Furthermore, the use of gas as a calibration medium (especially for measuring instruments with a pressure drop) results in an adjustable range and a maximum flow rate that can be achieved under different conditions. This is due to the maximum permissible velocity of the fluid through the vibrating meter. For example, at lower pressures, the maximum mass flow rate through the vibrating meter is significantly reduced. Therefore, instead of generating a mass error relative to the mass flow rate, the measuring instrument behavior can be described in terms of the mass error relative to a fluid velocity-related parameter of the gas flow, such as a fraction of the speed of sound or the Mach number. The Mach number of a gas is defined as the velocity of the gas divided by the speed of sound and is described by equation [2]:

[0077]

[0078] in:

[0079] M is the Mach number;

[0080] v is the fluid velocity; and

[0081] c is the speed of sound in the fluid.

[0082] Since hydrogen (H 2 ) has a low density, and the speed of sound of most alternative gases is lower than that of H 2 This may make H 2 The maximum mass / volume flow rate of the gas is significantly higher than that of most other gases. For example, the Mach 0.3 flow rate of natural gas, which has a sound speed of 466 m / s, may be about 140 m / s. In contrast, the speed of sound of H2O is equal to 1320 m / s. 2 The Mach 0.3 flow rate for a gas might be about 396 m / s (2.8 times higher than natural gas). The maximum flow rate (Qmax) of the vibrating meter can be set to 0.3 Mach for all gas compositions, which will be a different maximum velocity in m / s for each different gas (depending on the speed of sound in that gas).

[0083] Correction method using fluid velocity related parameters

[0084] As suggested above and described in more detail below, a solution for transferability between gases and the adjustable range and maximum flow rate of the vibrating meter is to apply a mass flow rate error correction relationship based on a fluid velocity related parameter (e.g., Mach number, fluid velocity, etc.) to linearize the output of the vibrating meter based on the Mach number or fluid velocity of the gas flow. The fluid velocity related parameter may be any parameter that is or includes a fluid velocity term.

[0085] In the specific example of Mach number and fluid velocity, Mach number may be preferred over fluid velocity when the gas molecular weight and / or speed of sound are known from analysis of the chemical composition of the gas. However, if the characteristics and composition of the gas are not known by measuring only the mass flow rate and flow density of the gas and the known cross-sectional area of ​​the flow tube through which the flow meter is applied, the fluid velocity method may be used. Exemplary specific details of these calculations are discussed below.

[0086] The fluid velocity can be determined using equation [3].

[0087]

[0088] in:

[0089] v is the fluid velocity;

[0090] is the mass flow rate (e.g., lbs / sec);

[0091] A is the cross-sectional area of ​​the fluid flow (ft 2 );as well as

[0092] ρ is the density of the fluid flow (lbs / ft 3 ).

[0093] The Mach number in English units can be determined using equation [4] or equation [5]:

[0094]

[0095]

[0096] in:

[0097] is the mass flow rate (e.g., lbs / sec);

[0098] A is the cross-sectional area of ​​the fluid flow (ft 2 );as well as

[0099] ρ is the density of the fluid flow (lbs / ft 3 ).

[0100] T is the absolute temperature of the gas;

[0101] z is the supercompressibility of the gas;

[0102] k is the specific heat ratio of the gas;

[0103] mW is the molecular weight of the gas; and

[0104] SOS is the speed of sound of the gas.

[0105] To implement Mach number based compensation, a user of a vibrating meter (e.g., vibrating meter 5 described above) may need to input the molecular weight mW and / or speed of sound (SOS) of a calibration or surrogate gas during calibration, and subsequently input the molecular weight and / or SOS of the process gas being measured after the vibrating meter is installed. To calibrate and apply the necessary correction relationship (e.g., function, relationship, curve, ordered pair, etc.) for Mach number, the meter electronics will determine a calibration factor for each test flow rate based on the Mach number to be determined from the flow rate (determined from mass flow rate, density, and meter cross-sectional area) and the molecular weight or speed of sound of the calibration gas.

[0106] The mass flow rate error correction relationship (whether based on Mach number, fluid velocity, or other) can be formed by any standard method of fitting a curve to the calibration data, such as linear interpolation between adjacent points or a polynomial fit. All corrections subsequently applied during process gas measurement can be determined, for example, by a linearization correction algorithm, and can be based on fluid velocity, Mach number, or other fluid velocity related parameters observed at the same fluid velocity value, Mach number, etc., and matching the errors observed during calibration. Once the meter electronics (such as the meter electronics 20 described above) has determined m a or v, then a lookup table and / or curve will be used to look up the linearized compensation value stored at any measured Mach number or fluid velocity. This mass flow rate error compensation value can then be used to compensate the mass flow rate value, as shown in the following exemplary formula [6]:

[0107]

[0108] in:

[0109] is the measured mass flow rate (eg, the current or uncompensated measured mass flow rate);

[0110] is the compensated mass flow rate; and

[0111] L mach is a linearization compensation factor based on Mach number (%) (or fluid velocity).

[0112] As will be appreciated, any suitable method of determining the corrected mass flow rate value may be employed, including methods that do not rely on equation [6] above.

[0113] Figure 3 Meter electronics 20 are shown for determining and using a mass flow rate error compensation relationship for a vibrating meter 5. Figure 3 As shown, meter electronics 20 includes an interface 301 and a processing system 302. Meter electronics 20 receives a vibration response from a sensor assembly, such as sensor assembly 10. Meter electronics 20 processes the vibration response to obtain flow characteristics of a flowing material flowing through sensor assembly 10. Meter electronics 20 may also perform checks, verifications, calibration routines, etc. to ensure accurate measurement of the flow characteristics of the flowing material.

[0114] Interface 301 can be from Figure 1 and Figure 2 The interface 301 may receive the sensor signal 165 from one of the pickup sensors 1701, 170r shown in FIG. 1 . The interface 301 may perform any necessary or desired signal conditioning, such as any form of formatting, amplification, buffering, etc. Alternatively, some or all of the signal conditioning may be performed in the processing system 302. In addition, the interface 301 may enable communication between the meter electronics 20 and an external device. The interface 301 may be capable of any manner of electronic, optical, or wireless communication. The interface 301 may provide information based on the vibration response. The interface 301 may be coupled to a digitizer (e.g., Figure 2 The sensor signal includes an analog sensor signal. The digitizer samples and digitizes the analog sensor signal and generates a digitized sensor signal.

[0115] The processing system 302 performs the operations of the meter electronics 20 and processes the flow measurements from the sensor assembly 10. The processing system 302 executes one or more processing routines and thereby processes the flow measurements to produce one or more flow characteristics. The processing system 302 is communicatively coupled to the interface 301 and is configured to receive information from the interface 301.

[0116] Processing system 302 may include a general purpose computer, a microprocessing system, a logic circuit, or some other general or custom processing device. Additionally or alternatively, processing system 302 may be distributed among multiple processing devices. Processing system 302 may also include any form of integrated or independent electronic storage media, such as storage system 304.

[0117] The storage system 304 can store vibration meter parameters and data, software routines, constant values, and variable values. In one embodiment, the storage system 304 includes routines executed by the processing system 302, such as the operation routine 310, calibration routine 320, and correction routine 330 of the vibration meter 5. The storage system can also store statistical values, such as mean values, standard deviations, confidence intervals, etc.

[0118] The operating routine 310 may determine a mass flow rate value 312 and a density value 314 based on the sensor signals received through the interface 301. Thus, the mass flow rate value 312 may be an uncorrected and directly measured mass flow rate value, etc. The mass flow rate value 312 may be determined based on the sensor signals, such as a time delay between a left pickoff sensor signal and a right pickoff sensor signal. The density value 314 may also be determined based on the sensor signals, such as by determining a frequency based on one or both of the left pickoff sensor signal and the right pickoff sensor signal.

[0119] The calibration routine 320 may perform the above-described zero verification, flow calibration factor determination, and / or mass flow rate error relationship determination and / or correction, but any suitable calibration routine may be employed. Thus, the calibration routine 320 may determine a plurality of mass flow rate errors 322. The mass flow rate errors 322 may be based on the mass flow rate and / or based on a fluid velocity related parameter (e.g., Mach number, fluid velocity, etc.). For example, the mass flow rate errors 322 may include one or more relationships (e.g., two tables, functions, etc.) that relate the mass flow rate and / or the Mach number or fluid velocity to the mass flow rate errors.

[0120] The storage system 304 is also shown to include a correction routine 330. The correction routine 330 can use a mass flow rate error correction relationship 332 to correct an uncorrected mass flow rate (eg, Figure 3 312) to determine a corrected mass flow rate value 334. For example, the mass flow rate error correction relationship 332 may be a function of the mass flow rate error 322 determined based on the calibration routine 320. The mass flow rate error correction relationship 332 may be based on a fluid velocity-based parameter (e.g., Mach number or fluid velocity) of the surrogate gas flow, as described in more detail below.

[0121] Measurement errors related to mass flow rate relative to fluid velocity

[0122] As described above, a surrogate gas flow may be used during calibration to determine a mass flow rate error correction relationship that can be used to correct the uncorrected mass flow rate value. However, a mass flow rate error correction relationship based on mass flow rate may not be transferable to other gases. Figures 4 to 9As shown, the mass flow rate error correction relationship based on a fluid velocity related parameter (e.g., Mach number or fluid velocity) can be transferred to other gases, including those gases such as hydrogen that have significantly unique mass flow rate based nonlinearities due to high compressibility.

[0123] Figure 4 A graph 400 illustrating the lack of a discernible relationship between mass flow rate error percentage and mass flow rate is shown. Figure 4 As shown, the chart 400 includes a mass flow rate axis 410 in kilograms per hour (kg / hr) and a mass flow rate error axis 420 with a unitless percentage scale. The range of the mass flow rate axis 410 is 0.00 kg / hr to 450 kg / hr, and the range of the mass flow rate error axis 420 is -1.0% to 1.0%. The chart 400 also includes a mass flow rate error scatter plot 430 of air at different mass flow rates and pressures. As can be understood from the legend 440, the pressure range of the air flow is 7 bar to 50 bar. As can also be understood from the mass flow rate error scatter plot 430 and the legend 440, the air flow is tested several times at each pressure.

[0124] Figure 5 A graph 500 illustrating a discernible relationship between mass flow rate error percentage and fluid velocity related parameters is shown. Figure 5 As shown, the chart 500 includes a fluid velocity axis 510 having a unitless Mach number and a mass flow rate error axis 520 having a unitless percentage scale. The range of the fluid velocity axis 510 is 0.00 Mach to 0.35 Mach, and the range of the mass flow rate error axis 520 is -1.0% to 1.0%. The chart 500 also includes a mass flow rate error scatter plot 530 of air at different mass flow rates and pressures. As can be understood from the legend 540, the pressure range of the air flow is 7 bar to 50 bar. As can also be understood from the mass flow rate error scatter plot 530 and the legend 540, the air flow is tested several times at each pressure.

[0125] Figure 6 A graph 600 illustrating a discernible relationship between mass flow rate error percentage and fluid velocity related parameters is shown. Figure 6As shown, the chart 600 includes a fluid velocity axis 610 having a unitless Mach number and a mass flow rate error axis 620 having a unitless percentage scale. The range of the fluid velocity axis 610 is 0.00 to 0.35, and the range of the mass flow rate error axis 620 is -2.0% to 2.0%. The chart 600 also includes a mass flow rate error scatter plot 630 of air at different mass flow rates and pressures. As can be understood from the legend 640, the pressure range of the air flow is 1.3 bar to 20 bar. As can also be understood from the mass flow rate error scatter plot 630 and the legend 640, the air flow is tested several times at each pressure.

[0126] As from Figures 4 to 6 Understandably, Figure 4 The mass flow rate error scatter plot 430 shown has no discernible relationship between the mass flow rate error values ​​and the mass flow rate values. Figure 5 The mass flow rate error scatter plot 530 and Figure 6 The mass flow rate error scatter plot 630 shown has a significantly better and more discernible relationship between the mass flow rate error value and the Mach number. Figure 5 and Figure 6 As can also be understood from the above, the relationship between the mass flow rate error and the Mach number is discernible at various air pressure values. Figures 7 to 9 It is shown that the mass flow rate error correction relationship based on fluid velocity related parameters (eg, Mach number, fluid velocity, etc.) can be transferred between different gases.

[0127] Exemplary Correction of Mass Flow Rate of Process Fluid

[0128] Figure 7 A graph 700 illustrating the lack of a discernible relationship between mass flow rate error percentage and mass flow rate is shown. Figure 7 As shown, the chart 700 includes a mass flow rate axis 710 in pounds per minute (lbs / min) and a mass flow rate error axis 720 with a unitless percentage scale. The range of the mass flow rate axis 710 is 0.00 lbs / min to 500 lbs / min, and the range of the mass flow rate error axis 720 is -1.0% to 1.0%. The chart 700 also includes a mass flow rate error scatter plot 730 of air, natural gas, and carbon dioxide at different mass flow rates and pressures. As can be understood from the legend 740, the pressure of the air flow is 900 pounds per square inch gauge (psig), the pressure of the natural gas is 700 psig, and the pressure of the carbon dioxide is 225 psig. As can also be understood from the mass flow rate error scatter plot 730 and the legend 740, the air, natural gas, and carbon dioxide flows were tested at various mass flow rates up to about 400 lbs / min.

[0129] With reference Figure 4 The mass flow rate error scatter plot 430 is similar, Figure 7 The mass flow rate error scatter plot 730 shown also does not have a discernible relationship between the mass flow rate error values ​​and the mass flow rate values ​​for the different gases. Figure 8 and Fig. 9 ,It can be understood that for different gases, there is a discernible relationship between the mass flow rate error value and the fluid velocity related parameter values, especially the Mach number, and due to the discernible relationship, a quantifiable relationship between the mass flow rate measurement error and the fluid velocity related parameters can be constructed.

[0130] Figure 8 A graph 800 illustrating a discernible relationship between mass flow rate error percentage and fluid velocity related parameters is shown. Figure 8 As shown, the chart 800 includes a fluid velocity axis 810 having a unitless Mach number and a mass flow rate error axis 820 having a unitless percentage scale. The range of the fluid velocity axis 810 is from 0.00 to 0.35, and the range of the mass flow rate error axis 820 is from -0.6% to 0.6%. The chart 800 also includes a mass flow rate error scatter plot 830 of air, natural gas, and carbon dioxide at various fluid velocities and pressures. As can be appreciated from the legend 840, the pressure of the air flow is 900 psig, the pressure of the natural gas is 700 psig, and the pressure of the carbon dioxide is 225 psig. As can also be understood from the mass flow rate error scatter plot 830 and the legend 840, the air, natural gas, and carbon dioxide flows were tested at various fluid velocities up to 0.30 Mach. Figure 8 Also shown in is a piecewise linear (PWL) function 850 determined from the regression analysis of the CO2 data. Specifically, the mean of each set of CO2 mass flow rate error values ​​at each speed (Mach) value is determined. A line is constructed at each mean with each endpoint.

[0131] Fig. 9 A graph 900 is shown illustrating a discernible relationship between mass flow rate error percentage and a fluid velocity related parameter after applying a mass flow rate error correction relationship. Fig. 9As shown, the chart 900 includes a fluid velocity axis 910 having a unitless Mach number and a mass flow rate error axis 920 having a unitless percentage scale. The range of the fluid velocity axis 910 is 0.00 to 0.35, and the range of the mass flow rate error axis 920 is -0.6% to 0.6%. The chart 900 also includes a mass flow rate error scatter plot 930 of air, natural gas, and carbon dioxide at different fluid velocities and pressures. As can be understood from the legend 940, the pressure of the air flow is 900 psig, the pressure of the natural gas is 700 psig, and the pressure of the carbon dioxide is 225 psig. As can also be understood from the mass flow rate error scatter plot 930 and the legend 940, the air, natural gas, and carbon dioxide flows were tested at various fluid velocities up to 0.30 Mach.

[0132] Fig. 9 The mass flow rate error scatter plot 930 is calculated by Figure 8 The PWL function 850 is applied as a correction function to Figure 8 In particular, the value of the PWL function 850 is subtracted from one or more values ​​of the mass flow rate error scatter plot 830. Fig. 9 As can be appreciated, the mass flow rate error values ​​of the mass flow rate error scatter plot 930 are less than 0.4%, and in most cases less than 0.2%.

[0133] Although PWL function 850 is determined by averaging carbon dioxide, any suitable method of determining any suitable relationship between mass flow rate error and fluid velocity related parameter, such as one or more functions, ordered pair tables, etc., may be used. For example, an alternative function may be a PWL function having endpoints determined by averaging the mass flow rate error values ​​for all gases over a range of fluid velocity related parameter values. As an illustration, Figure 8 As shown, natural gas and air are often measured at approximately the same Mach number. Additionally or alternatively, the alternative function and / or ordered pair may be non-linear based and / or determined using non-linear regression, such as one or more polynomial functions and / or polynomial regression.

[0134] As can be understood from the previous discussion, determining the mass flow rate error relationship may require determining a "known" mass flow rate. The known mass flow rate can be provided by, for example, a reference flow meter, a source that provides a gas flow at a gas flow rate within a very small range of set point values, etc. These and other devices can be collectively referred to as reference devices. The reference device can be connected in series with a vibrating meter (such as the vibrating meter 5 described above). Therefore, the reference device can therefore provide a known or reference mass flow rate and / or fluid velocity related parameter value that can be used to calibrate the vibrating meter in series. An exemplary system utilizing a reference device is described below.

[0135] system

[0136] Fig.10 A system 1000 for determining a mass flow rate error correction relationship for a vibrating meter is shown. Fig.10 As shown, the system 1000 includes the vibrating meter 5 described above, but any suitable vibrating meter may be used. The vibrating meter 5 is shown in series and in fluid communication with the reference device 1010. That is, the reference device 1010 and the vibrating meter 5 convey the same gas flow. Therefore, a valid assumption can be made that the measured values ​​of the parameters of the gas flow determined by the vibrating meter 5 and the reference device 1010 should be the same. In addition, a valid assumption can be made that any difference between the measured values ​​of the parameters determined by the vibrating meter 5 and the reference device 1010 is due to measurement errors of the vibrating meter 5.

[0137] like Fig.10 As shown, the system 1000 includes a calibration circuit 1020 communicatively coupled to the vibrating meter 5 and the reference device 1010. The calibration circuit 1020 is shown in dashed lines to illustrate that the calibration circuit 1020 may or may not be separate from the vibrating meter 5 and / or the reference device 1010, and may or may not be unitary. Regardless of the form factor, the calibration circuit 1020 can determine the difference between the measured values ​​of the parameter of the gas flow provided by the vibrating meter 5 and the reference device 1010.

[0138] The difference between the measured values ​​of the parameter of the gas flow may be a measured mass flow rate difference between the mass flow rate values ​​provided by the vibrating meter 5 and the reference device 1010, which may be referred to as a measured mass flow rate difference. The measured mass flow rate difference may be divided by the mass flow rate value provided by, for example, the reference device, and then multiplied by 100 to determine a mass flow rate error value in percentage form.

[0139] In addition, the calibration circuit 1020 may obtain the fluid flow rate or fluid velocity related parameters from the reference device 1010 and / or the vibrating meter 5. For example, the calibration circuit 1020 may obtain the mass flow rate and / or fluid velocity related parameters, such as the fluid velocity and / or Mach number of the gas flow, from the reference device 1010. Therefore, the calibration circuit 1020 may determine (e.g., calculate) a plurality of mass flow rate errors of the vibrating meter 5 at a plurality of corresponding mass flow rate and / or fluid velocity related parameter values.

[0140] The calibration circuit 1020 may also determine one or more functions, ordered pairs, etc. that relate mass flow rate values ​​and / or fluid velocity related parameter values ​​(e.g., fluid velocity values ​​or Mach numbers) to mass flow rate error correction values, as described above with reference to Fig. 9Thus, the system 1000 or in particular the reference device 1010 (whether standalone or integrated with the vibrating meter 5 and / or the reference device 1010) can provide one or more functions, ordered number pairs, etc., which can be used to correct the measured mass flow rate errors of the vibrating meter 5. An exemplary method of doing so is discussed in detail below.

[0141] method

[0142] Fig.11 A method 1100 for determining a mass flow rate error correction relationship for a vibrating meter, such as the vibrating meter 5 described above, is shown. Fig.11 As shown, the method 1100 compares each of the plurality of mass flow rate measurements of the alternative gas flow with a corresponding each of the plurality of reference mass flow rate measurements of the alternative gas flow in step 1110. In step 1120, the method 1100 determines a plurality of mass flow rate measurement errors corresponding to a plurality of fluid velocity-related parameter values ​​of the alternative gas flow based on the comparison.

[0143] As mentioned above Fig.10 As described above, multiple reference mass flow rate measurements can be made by a reference device (e.g., a reference Fig.10 Thus, for example, the steps of method 1100 may be performed by a system 1000 that includes a vibration meter 5 configured to measure the mass flow rate of a surrogate gas flow, a reference device 1010 connected in series with the vibration meter 5, and a calibration circuit 1020 that communicates with the vibration meter 5 and the reference device 1010.

[0144] For example, the vibrating meter 5 may determine a mass flow rate measurement and the reference device 1010 may determine a reference mass flow rate of the surrogate gas flow. Thus, the reference device 1010 may provide a plurality of reference mass flow rate measurements of the surrogate gas flow in series with the vibrating meter 5. The calibration circuit 1020 may use the mass flow rate measurements and the reference mass flow rate of the surrogate gas flow configured to perform the method 1100.

[0145] As can be understood from the above discussion, the plurality of fluid velocity-related parameter values ​​of the alternative gas flow may include one of a plurality of fluid velocity values ​​and a plurality of Mach numbers of the alternative gas flow. The alternative gas flow may include air, natural gas, carbon dioxide, nitrogen, and / or helium. Figure 8 and Fig. 9As shown in the related previous discussion, the plurality of mass flow rate measurement errors and the mass flow rate error correction relationships generated therefrom are transferable to another gas, such as hydrogen. The plurality of mass flow rate measurement errors corresponding to the plurality of fluid velocity related parameter values ​​of the alternative gas flow may include a plurality of differences between each of the plurality of mass flow rate measurements and a corresponding each of the plurality of reference mass flow rate measurements.

[0146] The method 1100 may also include additional steps. For example, the method 1100 may include passing the alternative gas flow through the vibrating meter 5, but any suitable vibrating meter may be used. Thus, the vibrating meter may provide a plurality of mass flow rate measurements. Additionally or alternatively, the method 1100 may also include determining, using the vibrating meter 5, a plurality of mass flow rate measurements of the alternative gas flow at a plurality of fluid velocity related parameter values. This may include calculating the fluid velocity related parameter values ​​according to equations [2] to [5] above, but any suitable equation may be used.

[0147] The method 1100 may also store the plurality of mass flow rate measurement errors as a plurality of ordered pairs of the plurality of mass flow rate measurement errors and the corresponding plurality of fluid velocity related parameter values ​​in a meter electronics of a vibrating meter, such as the meter electronics 20 of the vibrating meter 5 described above. Thus, the meter electronics may subsequently determine a mass flow rate error correction relationship, such as the mass flow rate error correction relationship may be determined after the vibrating meter 5 is installed in a process application.

[0148] The method 1100 may also determine a mass flow rate error correction relationship based on the plurality of mass flow rate measurement errors and the corresponding plurality of fluid velocity related parameter values, and store the mass flow rate error correction relationship in the vibrating meter. For example, the calibration circuit 1020 (whether stand-alone, in the vibrating meter and / or in the reference device 1010) may determine the mass flow rate error correction relationship and store the mass flow rate error correction relationship in the meter electronics of the vibrating meter.

[0149] As can be appreciated, the stored mass flow rate error values ​​and / or mass flow rate error correction relationships can be used to correct the measured mass flow rate values ​​of the process gas measured by the vibrating meter. As previously described, the mass flow rate error values ​​and / or mass flow rate error correction relationships can be mass flow rate error values ​​and / or mass flow rate error correction relationships of the substitute gas and can still be used to correct the measured mass flow rate of the process gas.

[0150] Fig.12 A method 1200 for using a mass flow rate error correction relationship for a vibrating meter, such as the vibrating meter 5 described above, is shown. Fig.12As shown, method 1200 determines a fluid velocity related parameter value of the process gas flow based on the measured mass flow rate value, density value, and cross-sectional area of ​​the process gas flow in step 1210. In step 1220, method 1200 determines a mass flow rate error correction value based on the fluid velocity related parameter value.

[0151] As can be appreciated, the method 1200 can be performed by suitable meter electronics of a vibrating meter, such as the meter electronics 20 of the vibrating meter 5 described above. Figures 1 to 3 1 , the vibrating meter 5 includes a storage system 304 and a processing system 302 communicatively coupled to the storage system 304. The processing system 302 may be configured to perform the method 1200. One or more values ​​related to the process gas flow, such as the density or cross-sectional area of ​​the process gas flow, may be measured by the sensor assembly 10, input by a user, provided by another device, etc.

[0152] In step 1220, determining the mass flow rate error correction value based on the fluid velocity related parameter value may include obtaining a mass flow rate error correction relationship for the surrogate gas flow, and determining the mass flow rate correction value based on the mass flow rate error correction relationship for the surrogate gas flow and the fluid velocity related parameter value. The fluid velocity related parameter value may include one of a fluid velocity value and a Mach number of the process gas flow. As described above with reference to Fig.11 As described, the alternative gas stream may include one of air, natural gas, carbon dioxide, nitrogen and helium. Because the mass flow rate error correction relationship can be transferred to other gases as described above, the process gas stream may be a gas with a different compressibility factor, such as a hydrogen stream.

[0153] The method 1200 may include additional steps. For example, the method 1200 may also measure the mass flow rate of the process gas stream using a vibrating meter to determine a measured mass flow rate value. Additionally or alternatively, the method 1200 may correct the measured mass flow rate value using a mass flow rate error correction value.

[0154] The above-described vibrating meter 5, metering electronics 20, system 1000, and methods 1100 and 1200 can determine and use a mass flow rate error correction relationship. For example, method 1100 determines a mass flow rate error correction relationship based on a fluid velocity-related parameter of the alternative gas flow. Because the mass flow rate error correction relationship is based on a fluid velocity-related parameter, the mass flow rate measurement error and, more specifically, the mass flow rate error correction relationship can be transferred from the alternative gas flow to other gas flows. For example, the nonlinearity between different gas flows is approximately the same at Mach number, but is typically approximately different at mass flow rate. This may be due to the fact that the compressibility of various gases is taken into account when using the Mach number. Therefore, the measured mass flow rate of a highly compressible gas (e.g., hydrogen) can be corrected based on the mass flow rate measurement error of a gas (e.g., air, carbon dioxide, or natural gas) that has relatively low compressibility and is more readily available and cheaper.

[0155] In addition, due to the mass flow rate measurement error based on fluid velocity related parameters, the vibrating meter 5 can advantageously perform ranging. For example, as described above, unacceptable signal noise in a vibrating meter (such as the vibrating meter 5 described above) is typically present at gas flow rates above 0.30 Mach. However, highly compressible gases tend to have a relatively high speed of sound. Therefore, a given mass flow rate of a highly compressible gas may have a lower Mach number than a gas with a more typical speed of sound. Therefore, the vibrating meter 5 can measure a relatively high mass flow rate of a highly compressible gas without generating signal noise. For example, the vibrating meter 5 can be rated to measure a mass flow rate of hydrogen, for example, 3 times the mass flow rate of a non-highly compressible gas.

[0156] The detailed description of the above embodiments is not an exhaustive description of all embodiments contemplated by the inventors within the scope of this specification. In fact, those skilled in the art will recognize that certain elements of the above embodiments may be combined or eliminated in various ways to create other embodiments, and such other embodiments fall within the scope and teachings of this specification. Those of ordinary skill in the art will also understand that the above embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of this specification.

[0157] Therefore, although specific embodiments are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the present specification, as will be recognized by those skilled in the relevant art. The teachings provided herein can be applied to other vibrating meters, meter electronics, and methods for determining and using mass flow rate error correction relationships for vibrating meters, not just the embodiments described above and shown in the accompanying drawings. Therefore, the scope of the above embodiments should be determined according to the appended claims.

Claims

1. A method for determining a mass flow rate error correction value for a vibrating meter, the method comprising: include: comparing each mass flow rate measurement of a plurality of mass flow rate measurements of the alternative gas flow to a corresponding each reference mass flow rate measurement of a plurality of reference mass flow rate measurements of the alternative gas flow; as well as A plurality of mass flow rate measurement errors corresponding to a plurality of fluid velocity related parameter values ​​of the surrogate gas flow are determined based on the comparing.

2. The method according to claim 1, in, The plurality of fluid velocity related parameter values ​​of the alternative gas flow includes one of a plurality of fluid velocity values ​​and a plurality of Mach numbers of the alternative gas flow.

3. The method according to any one of claims 1 or 2, in, The plurality of reference mass flow rate measurements of the alternative gas flow are provided by a reference device connected in series with the vibrating meter.

4. The method according to any one of the preceding claims 1 to 3, in, The alternative gas stream includes one of air, natural gas, carbon dioxide, nitrogen and helium.

5. The method according to any one of the preceding claims 1 to 4, in, The plurality of mass flow rate measurement errors corresponding to the plurality of fluid velocity related parameter values ​​of the surrogate gas flow include a plurality of differences between each of the plurality of mass flow rate measurements and a corresponding each of the plurality of reference mass flow rate measurements.

6. The method of any one of the preceding claims 1 to 5, further comprising flowing the replacement gas stream through the vibrating meter.

7. The method of any one of the preceding claims 1 to 6, further comprising using the vibrating meter to determine the plurality of mass flow rate measurements at a corresponding plurality of fluid velocity related parameter values ​​of the alternative gas flow.

8. The method of any one of the preceding claims 1 to 7, further comprising storing the plurality of mass flow rate measurement errors as a plurality of ordered pairs of the plurality of mass flow rate measurement errors and corresponding plurality of fluid velocity related parameter values ​​in a meter electronics device of the vibrating meter.

9. The method of any one of the preceding claims 1 to 8, further comprising determining a mass flow rate error correction relationship based on the plurality of mass flow rate measurement errors and a corresponding plurality of fluid velocity related parameter values, and storing the mass flow rate error correction relationship in the vibrating meter.

10. A system (1000) for determining a mass flow rate error correction relationship for a vibrating meter (5), the system (1000) include: The vibrating meter (5) is configured to measure the mass flow rate of the alternative gas flow; a reference device (1010) connected in series with the vibrating meter (5), the reference device (1010) being configured to determine a reference mass flow rate of the alternative gas flow; as well as A calibration circuit (1020) in communication with the vibrating meter (5) and the reference device (1010), the calibration circuit (1020) being configured to perform the method according to any one of the preceding claims 1 to 9.

11. A method for using a mass flow rate error correction relationship for a vibrating meter, the method include: determining a fluid velocity-related parameter value of the process gas flow based on a measured mass flow rate value, a density value, and a cross-sectional area of ​​the process gas flow; as well as A mass flow rate error correction value is determined based on the fluid velocity related parameter value.

12. The method according to claim 11, in, The fluid velocity related parameter value includes one of a fluid velocity value and a Mach number value of the process gas flow.

13. The method according to any one of claims 11 or 12, in, The process gas stream is a hydrogen stream.

14. The method of any one of the preceding claims 11 to 13, further comprising measuring the mass flow rate of the process gas stream using the vibrating meter to determine a measured mass flow rate value.

15. The method of any one of the preceding claims 11 to 14, further comprising correcting a measured mass flow rate value using the mass flow rate error correction value.

16. The method according to any one of the preceding claims 11 to 15, in, Determining the mass flow rate error correction value based on the fluid velocity related parameter value includes: obtaining the mass flow rate error correction relationship for a surrogate gas flow; and The mass flow rate correction value is determined based on the mass flow rate error correction relationship and the fluid velocity related parameter value for the alternative gas flow.

17. The method according to claim 16, in, The alternative gas stream includes one of air, natural gas, carbon dioxide, nitrogen and helium.

18. A meter electronics device (20) for using a mass flow rate error correction relationship, the meter electronics device (20) include: Storage system (304); as well as A processing system (302) communicatively coupled to the storage system (304), the processing system (302) being configured to perform the method according to any one of the preceding claims 11 to 17.

19. A vibrating meter (5) for using a mass flow rate error correction relationship, the vibrating meter (5) include: a sensor assembly (10) configured to measure a mass flow rate of a process gas flow; as well as Meter electronics (20) communicatively coupled to the sensor assembly (10), the meter electronics (20) being provided in accordance with the preceding claim 18.

Images