Method, system and electronics for correcting coriolis flow meter measurement for temperature effects

Abstract

To provide a Coriolis flow meter that enables more accurate fluid measurement at sub-zero and cryogenic temperatures.SOLUTION: Provided are a method, system and electronics for correcting a mass flow value m' measured using a Coriolis flow meter for temperature effects at a known fluid temperature temp below 0°C. The method comprises receiving a known fluid density ρref, receiving the known fluid temperature temp, receiving a time period Tp, determining a Young modulus temperature correction TFyD for the density on the basis of the known fluid density ρref, the known fluid temperature temp and the time period Tp, determining a Young modulus temperature correction TFyM for the mass flow on the basis of a temperature correction constant k and the Young modulus temperature correction TFyD for the density, and correcting the mass flow value m' using the Young modulus temperature correction TFyM for the mass flow.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] This application relates to Coriolis flow meters, and more particularly, to correcting Coriolis flow meter measurements for temperature effects. [Background technology]

[0002] Coriolis mass flow meters utilize the Coriolis force induced by a fluid flowing through one or more vibrating tubes to measure mass flow. Figure 1 shows an example of a Coriolis flow meter 100 including a meter assembly 10 and meter electronics 20. Meter assembly 10 responds to changes in process fluid flow. Meter electronics 20 is connected to meter assembly 10 via leads 102 and provides density, volumetric flow rate, and mass flow rate information, among other information, to an operator via meter electronics interface 26.

[0003] Meter assembly 10 includes manifolds 150 and 150', flanges 103 and 103', two parallel flow tubes 130 and 130', driver 180, and velocity pickoff sensors 170L and 170R. Flow tubes 130 and 130' are bent at two symmetrical locations along their length and are essentially parallel throughout their length. Brace bars 140 and 140' serve to define the axis about which each flow tube oscillates.

[0004] When flanges 103 and 103' are connected to a process line (not shown) via inlet end 104 and outlet end 104', process fluid enters the flowmeter through flange 103 at inlet end 104 and flows through manifold 150. Manifold 150 splits the process fluid and passes it through flow tubes 130 and 130'. Upon exiting flow tubes 130 and 130', the process fluid is recombined into a single stream by manifold 150' and directed to outlet end 104', which is connected to a process line (not shown) by flange 103'.

[0005] Both flow tubes 130 and 130' are driven in opposite directions in a first out-of-phase bending mode of the flowmeter by driver 180. Driver 180 may comprise any one of a number of well-known configurations, such as a magnet attached to flow tube 130' and an opposing coil attached to flow tube 130 through which an alternating current is passed to vibrate both flow tubes. An appropriate driver voltage is applied to driver 180 by meter electronics 20. In further embodiments, Coriolis flowmeter 100 may include multiple drivers 180 providing multiple input configurations capable of producing other bending modes.

[0006] Although Coriolis flowmeter 100 is shown with a double curved flow tube design, this is not intended to be limiting. One of ordinary skill in the art will appreciate that other examples of Coriolis flowmeter 100 can include one or any number of flow tubes. One of ordinary skill in the art will further appreciate that other Coriolis flowmeters can include straight flow tubes, or any other configuration.

[0007] Meter electronics 20 provides a drive signal to driver 180 to vibrate flow tubes 130 and 130' via leads 102. Meter electronics 20 receives left and right velocity signals from velocity pickoff sensors 170L and 170R via leads 102 and uses them to calculate the mass flow rate, volumetric flow rate, and / or density of the flow passing through meter assembly 10. The information can be calculated.

[0008] The left and right velocity signals from pickoff sensors 170L and 170R are used to determine a phase difference ΔT between pickoff sensors 170L and 170R, which represents the Coriolis force acting on the flow tube. The phase difference ΔT is used to determine the mass flow value m' using Equation 1.

number

[0009] where FCF is the flow rate calibration factor and ΔT is the zero offset. 0is determined during factory calibration. The FCF captures the stiffness of one or more flow tubes 130, 130', which is the force acting through the tube. It is directly proportional to the mass flow rate of the fluid flowing. The FCF is calculated by flowing water through a Coriolis mass flowmeter at ambient conditions. , is determined by comparing the indicated mass with the mass measured by a reference flow meter.

[0010] Corrections are typically made to the mass flow measurements of Coriolis flowmeter 100 after it is installed at a customer site to account for differences between the customer site and factory environmental conditions. For example, changes in temperature and fluid pressure can change the stiffness of flow tubes 130, 130', which can cause errors in the meter's mass flow and density measurements.

[0011] The temperature corrections required for mass flow and density measurements above 0°C are different from those required below 0°C. The correction made to the measured mass flow value m' for stiffness changes due to Young's modulus above 0°C is approximately linear. Below 0°C, the correction to the mass flow measurement m' is usually better represented by a polynomial.

[0012] It has been empirically observed that temperature correction of density measurements is not the same as temperature correction based on mass flow measurements at temperatures between 0 and 50 °C. However, it has been difficult to characterize the change in flow tube stiffness based on Young's modulus below 0 °C due to limitations in flow rates available in cryogenic calibration facilities. Thus far, it has only been possible to obtain empirical data to characterize the change in flow tube stiffness based on temperature for small flow meters, or flow meters with flow tubes 4 inches or smaller.

[0013] There is a need for more accurate mass flow measurement at sub-freezing and cryogenic temperatures. One potential application is the flow of large volumes of liquefied natural gas at temperatures of -160°C.

[0014] It would be highly desirable to provide more accurate flow measurements with Coriolis flow meters at sub-freezing and cryogenic temperatures. Summary of the Invention

[0015] A technique is provided for correcting mass flow values ​​m' measured using a Coriolis flowmeter for temperature effects at a known fluid temperature temp less than 0° C. The method includes receiving a known fluid density ρref, receiving the known fluid temperature temp, and receiving a time period Tp. and based on the known fluid density ρref, the known fluid temperature temp, and the time period Tp Temperature correction of Young's modulus of density TFy D determining a temperature correction constant k and a Yang value of said density; Temperature compensation of TFy D Young's modulus temperature correction of mass flow rate based on TFy M and determining a Young's modulus temperature correction TFy of the mass flow rate. M and correcting the mass flow value m′ using:

[0016] A system is provided for correcting mass flow values ​​m' measured using a Coriolis flowmeter for temperature effects at a known fluid temperature temp less than 0° C. The system includes a fluid density receiving module configured to receive a known fluid density ρref, a fluid temperature receiving module configured to receive a known fluid temperature temp, and a time period Tp. and determining a temperature correction TFy of Young's modulus of density based on the known fluid density ρref, the known fluid temperature temp, and the time period Tp. D Configured to determine a module for determining a temperature correction constant k and a Young's modulus of said density; Rate temperature correction TFy D Young's modulus temperature correction of mass flow rate based on TFy M A mass flow Young's modulus temperature correction determination module configured to determine the mass flow Young's modulus temperature correction TFy M and a mass flow correction module configured to correct the mass flow value m′ using

[0017] Meter electronics are provided for correcting mass flow values ​​m' measured using a meter assembly (10) of a Coriolis flowmeter (100) for temperature effects at known fluid temperatures less than 0° C. The meter electronics includes a system processor that receives a known fluid density ρref, receives the known fluid temperature temp, receives a time period Tp, and calculates a temperature coefficient m' for the known fluid temperature ρref. The known fluid density ρref, the known fluid temperature temp, and the time period Tp are used to calculate the density of the Yang Temperature compensation of TFy D Determine a temperature correction constant k and a temperature correction Young's modulus of said density TFy D Based on Young's modulus temperature correction TFy for mass flow rate M and determining a Young's modulus temperature correction TFy of said mass flow rate. M The mass flow value m′ is corrected using:

[0018] [Aspects] According to a further aspect, the time period Tp is determined by the measured fluid density ρ indic Based on Ugh. According to a further aspect, the method may further include receiving a phase difference ΔT. , Young's modulus temperature correction TFy D Determining further based on the phase difference ΔT It's fine.

[0019] According to a further aspect, the method may further include receiving a fluid pressure P. , Young's modulus temperature correction TFy D may further be based on the fluid pressure P.

[0020] According to a further aspect, the method further comprises determining an expansion temperature correction TFe for the density. The density can be calculated by the Young's modulus temperature correction TFy D is the known temperature refBased on the above The expansion temperature correction TFe may be further determined based on the degree of expansion temperature correction TFe.

[0021] According to a further embodiment, the temperature correction constant k may be between 0.8 and 1.2.

[0022] According to a further aspect, the temperature correction constant k may be one.

[0023] According to a further aspect, the Young's modulus temperature correction TFy of the mass flow rate M Correcting the mass flow value m' using the Young's modulus temperature correction TFy M Using the mass error value Error m may further include determining:

[0024] According to a further aspect, the fluid density receiving module is adapted to receive a measured fluid density ρ indic Determine and the period determination module may be further configured to: indic The time period Tp may be further configured to determine the time period Tp based on

[0025] According to a further aspect, the system includes a phase difference detector configured to determine a phase difference ΔT. The temperature compensation module may further include a Young's modulus of density temperature compensation determination module, which determines the Young's modulus of density temperature compensation TFy based on the phase difference ΔT. D Further, to determine It may be configured as follows.

[0026] According to a further aspect, the system includes a measuring fluid pressure P indic The fluid pressure determination module may further be configured to determine the Young's modulus temperature correction of density TFy based on the fluid pressure P. D Determine The device may be further configured as follows.

[0027] According to a further aspect, the system includes a known temperature temp ref Density expansion temperature based on The expansion temperature compensation module may further include a compensation TFe. The density Young's modulus temperature compensation module calculates the Young's modulus of expansion based on the density expansion temperature compensation TFe. Density Young's modulus temperature correction TFy D The device may be further configured to determine:

[0028] According to a further embodiment, the temperature correction constant k can be between 0.8 and 1.2.

[0029] According to a further embodiment, the temperature correction constant k may be one.

[0030] According to a further aspect, the mass flow correction module is configured to calculate a Young's modulus temperature correction TFy M Using the mass error value Error m The device may be further configured to determine:

[0031] According to a further aspect, the time period Tp is determined by the measured fluid density ρ indic Based on It may be possible.

[0032] According to a further aspect, the system processor is further adapted to receive the phase difference ΔT. and a temperature-corrected Young's modulus of density TFy D Determining may be based on the phase difference ΔT.

[0033] According to a further aspect, the system processor is further adapted to receive the fluid pressure P. and a temperature-corrected Young's modulus of density TFy D is further calculated based on the fluid pressure P. It is okay to use it.

[0034] According to a further aspect, the system processor determines a density expansion temperature correction TFe. The temperature-corrected Young's modulus of the density TFy may be further corrected. D is the known temperature ref The density may further be determined based on a temperature expansion correction TFe based on

[0035] According to a further embodiment, the temperature correction constant k can be between 0.8 and 1.2.

[0036] According to a further embodiment, the temperature correction constant k may be one.

[0037] According to a further aspect, the Young's modulus temperature correction TFy of the mass flow rate M Correcting the mass flow value m' using the Young's modulus temperature correction TFy M Using the mass error value Error m may further include determining: [Brief description of the drawings]

[0038] Like reference numbers represent like elements in all drawings. The drawings are not necessarily to scale. [Figure 1] FIG. 1 shows a Coriolis flowmeter 100 . [Diagram 2] FIG. 2 illustrates a system 200 according to one embodiment. [Diagram 3] FIG. 3 illustrates a method 300 according to one embodiment. [Figure 4] FIG. 4 illustrates a system 400 according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] 2-4 and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of the present application. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these examples that fall within the scope of the present application. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple, varying aspects of the present application. As a result, the application is not limited to the specific examples described below, but only by the claims and their equivalents.

[0040] 2 illustrates a system 200 according to one embodiment. System 200 can be used to temperature compensate a mass flow value m' measured using a Coriolis flowmeter for temperature effects at fluid temperatures below 0° C. For example, system 200 can be used to provide temperature compensation, such as due to Young's modulus, elastic modulus, thermal expansion, or pressure effects, based on the measured temperature of the mass flow value m' in the Coriolis flowmeter.

[0041] The system 200 includes the Coriolis flowmeter 100, the meter electronics 20, and a process conduit 206. The process conduit 206 carries the fluid flow to be measured by the Coriolis flowmeter 100.

[0042] Meter electronics 20 may be used to generate a mass flow value m' of a fluid measured by meter assembly 10 of Coriolis flowmeter 100 or to correct a mass flow value m' obtained using meter assembly 10. Meter electronics 20 includes memory 20a, a system processor 20b, and an interface 20c.

[0043] The memory 20a includes an electronically readable medium or a computer readable medium configured to store computer program instructions. In some examples, the memory 20a may include a non-transitory medium. The computer program instructions stored in the memory 20a may perform some or all of the steps described in connection with the method 300 or perform some or all of the modules of the system 400.

[0044] System processor 20b may be configured to execute computer instructions to perform some or all of the steps described in connection with method 300 or to execute some or all of the modules described in connection with system 400. In some embodiments, system processor 20b may include a single processor or any multiple processors, as will be appreciated by those skilled in the art.

[0045] Interface 20c is configured to communicate with meter assembly 10 of Coriolis flowmeter 100. Interface 20c may be configured to communicate with devices external to electronics 20, such as, for example, a pressure sensor, a temperature sensor, or any other sensor known to one of ordinary skill in the art.

[0046] In some embodiments, the system 200 may include an additional measurement device 208. In some embodiments, the additional measurement device 208 may include a device capable of providing a density measurement, such as a density meter, a gas chromatograph, an additional Coriolis meter, or any other type of measurement device known to one of skill in the art. In some embodiments, the additional measurement device 208 may include corresponding meter electronics 204, as shown in FIG. 2. The meter electronics 204 may include a memory 204a, a system processor 204b, and an interface 204c, similar to the meter electronics 20. However, in further embodiments, the additional measurement device 208 may provide signals and information directly to the interface 20c of the meter electronics 20.

[0047] In further embodiments, the system 200 may include a server 202. In some embodiments, the server 202 may be in communication with the interface 20c of the meter electronics 20 and / or the interface 204c of the meter electronics 204. Any portion of the steps described in connection with the method 300 or modules described in connection with the system 400 may be stored or executed on the server 202.

[0048] 3 illustrates a method 300 according to one embodiment. The method 300 calculates a mass flow value m' measured using a Coriolis flowmeter at a known fluid temperature temp less than 0° C. ref Regarding temperature effects in For example, method 300 can be used to provide measurement corrections based on the measured temperature of the mass flow value m′ in Coriolis flowmeter 100, such as to correct for changes related to changes in Young's modulus, elastic modulus, thermal expansion coefficient, or pressure effects.

[0049] The method 300 begins at step 302. In step 302, a known fluid density ρref is received. The method 300 continues at step 304. In step 304, A known fluid temperature temp is received. The known fluid density ρref and the known fluid temperature temp are given by: The properties of the fluid being measured are well understood.

[0050] Method 300 continues at step 310. In step 310, a time period Tp is received. The time period Tp is the time period of the vibrating flow conduits 130, 130'. In some embodiments, the time period Tp can be measured directly using a vibration sensor connected to the flow conduits 130, 130', including, for example, one or both of the left and right velocity pickoff sensors 170L and 170R of Coriolis flowmeter 100.

[0051] However, in a further embodiment of step 310, the time period Tp is indic, the phase difference ΔT, and the fluid pressure P can be indirectly determined as follows: Cut.

[0052] In a method in which the time period Tp is indirectly determined, step 310 may further include steps 306 and 308. In step 306, a fluid pressure P is received. In this embodiment, the fluid pressure P is measured in the process conduit 206 by the Coriolis flowmeter 100 However, in further embodiments, the fluid pressure P may include a pressure measurement internal to the Coriolis flowmeter 100. , or any other fluid pressure measurement known to one of ordinary skill in the art. In some embodiments, the fluid pressure P may include a known or estimated fluid pressure.

[0053] In step 308, the phase difference ΔT is received. The phase difference ΔT is measured using the velocity pickoff sensors 170L and 170R of the Coriolis flowmeter 100. However, in a further embodiment, the phase difference ΔT can be determined by any method known in the art. As will be understood by those skilled in the art, the measured mass flow value m', FCF, composite temperature coefficient TF, and flow rate Body temperature can be determined indirectly using temp.

[0054] In some embodiments, the measured fluid density ρ indic should be measured using a density meter. For example, the measured fluid density ρ indic The system 200 may include a density meter. In a further embodiment, the additional measuring device 208 of the system 200 may receive the measured fluid density ρ indic Gas company that can provide A chromatograph may be included.

[0055] Coriolis flowmeters 100 are typically calibrated at factory conditions at a temperature of 20-30° C. In many cases, Coriolis flowmeters use two fluids, such as ambient air and water, to measure the mass flow rate, m', and the measured fluid density, ρ, of each fluid. indic The mass flow rate is calibrated by determining the value of value m' and the measured fluid density ρ indic Using these measurements, one for each fluid The calibration constant K 1 and K 2 can be sought.

[0056] Then, a calibration value C valid for a temperature of 0° C. and a pressure of 0 barg is 1 and C 2 is the calibration constant K 1 and K 2 The calibration value C can be calculated using Equations 2 and 3. 1 is the inertia model The flow rate is proportional to the force of the flow tubes 130, 130' and inversely proportional to the flow area of ​​the flow tubes 130, 130'.

number

number

[0057] Measured fluid density ρ indic can be determined using Equation 4.

number

[0058] Equation 4 can be rewritten as Equation 5.

number

number

[0059] The method 300 continues at step 314. In step 314, the Young's modulus of density temperature correction TFy D is determined. Young's modulus is affected by the expansion of the material with temperature and changes in the geometry of the flow tube, and to a lesser extent by pressure.

[0060] In some embodiments, the Young's modulus temperature correction TFy Dcan be determined using any method known to those skilled in the art. However, in a further embodiment, the Young's modulus of density temperature correction TFy D is based on the known fluid density ρref, fluid temperature temp, and time period Tp. The above can be determined.

[0061] For example, a known fluid density ρref is related to Young's modulus E(temp,P) by rigorous theory according to Equation 7:

number

number

[0062] In Equation 8, TFy is the temperature coefficient of Young's modulus. The elastic constant TFy can be nonlinear. For example, in the Journal of Applied Physics, "Elastic constants of stainless steels at low temperatures," written by Mr. HM Ledweigh in March 1981, the polynomial of Equation 9 is proposed for stainless steels at cryogenic temperatures.

number

[0063] In Equation 8, the known fluid density ρref further depends on TFe, the expansion temperature correction for density. The expansion temperature correction of density TFe may be determined using any method known to those skilled in the art. In some embodiments, step 314 can further include step 312, in which a density expansion temperature correction TFe is determined that is related to the expansion of the flow tube material. The determination can be based on experimental data.

[0064] In some embodiments, the density expansion temperature correction TFe can be non-linear. For example, , an article published in February 1978 by the Ukrainian Academy of Sciences entitled "Different Stabilities of "Low Temperature Thermal Expansion of Iron-Chromium-Nickel Alloys" presents the following polynomial10, which describes the temperature correction for thermal expansion at cryogenic temperatures:

number

[0065] Known fluid density ρref, phase difference ΔT, fluid pressure P, known fluid temperature temp ref , and the time period Tp, the Young's modulus temperature correction for density TFyd can be determined using Equation 11:

number

[0066] The Young's modulus of the flow tubes affects the vibration of the flow tubes 130, 130', so that both the mass flow rate measurement m' and the fluid density measurement ρ are affected by changes in Young's modulus. The tube vibration is a function of the material properties of the flow tubes 130, 130', which are typically made of steel.

[0067] However, in further embodiments, the FD*(ΔT) in Equation 11 2 *10 -9 The effect of flow on the fluid density represented by the term is very small and can therefore be neglected. Furthermore, the pressure coefficients of C1, PFC1, and PFC2 also account for the small changes in the Young's modulus temperature correction TFyd of density. Setting the flow effect of fluid density FD to zero and the pressure coefficients PFC1 and PFC2 to unity provides a simplified expression for the Young's modulus temperature correction of density TFyd, as shown in Equation 12.

number

[0068] Once the Young's modulus temperature correction for density, TFyd, is determined, the method 300 proceeds to step 316. In step 316, the Young's modulus temperature correction for mass flow, TFy, is calculated as expressed in Equation 13: M is the Young's modulus of density temperature correction TFy D It is determined based on the temperature correction constant k multiplied by

number

[0069] Young's modulus temperature correction for mass flow rate TFy M is generally related to the torque in the flow tube, and the Young's modulus of density temperature correction TFy D is commonly associated with bends in the flow tube. Initial testing in a calibration laboratory using flow meters with stainless steel tubes formed into a "U" shape has shown that these temperature corrections are substantially similar in value. Thus, in some embodiments, the temperature correction constant k may be set to 1. However, for more sensitive measurements, different tube materials and / or Subsequent tests using different tube geometries have shown that the Young's modulus of mass flow rate temperature correction TFy M and density Young's modulus temperature correction TFy D It may be evident that k is a different value. Thus, in other embodiments, the temperature correction constant k may be determined to be any number other than 1. In a limiting example, k may be set to a value between 0.8 and 1.2.

[0070] Young's modulus temperature correction for mass flow rate TFy M Once determined, method 300 proceeds to step 320. In step 320, the mass flow value m' determined using Coriolis flowmeter 100 in accordance with Equation 1 is converted into Young's modulus temperature correction TFy M In some embodiments, the mass flow value m′ is corrected using the Young's modulus temperature correction TFy for mass flow by any method known to one of skill in the art. M may be corrected using

[0071] In some embodiments, step 320 may further comprise step 318, in which the Young's modulus of mass temperature correction TFy M and the density expansion temperature correction TFe determined in steps 312 and 316 to obtain the mass error value Error m It is possible to determine Cut.

number

[0072] The first part of Equation 14 comes from the calibration and is the mass error value Error at 0°C and 0 barg. m and the second part of Equation 14 comes from the operating behavior in application and reflects the error value from 0°C and 0 barg to operating conditions. However, in practice, the first part of Equation 14 is small relative to the second part. Therefore, in an embodiment, Equation 14 can be simplified to Equation 15:

number

[0073] In some embodiments, the mass flow value m′ measured by the Coriolis flowmeter 100 is corrected. To do this, the meter factor MF can be determined using Equation 16.

number

[0074] A corrected mass flow value m' can then be determined by multiplying the measured mass flow value m' by the meter factor MF.

[0075] 4 illustrates a system 400. In some embodiments, the system 400 can be used to correct mass flow values ​​m' measured using Coriolis flowmeter 100 for temperature effects at fluid temperatures temp less than 0° C. The system 400 includes a fluid density receiving module 402, a fluid temperature receiving module 404, a period determining module 410, a Young's modulus temperature correction of density determining module 414, a Young's modulus temperature correction of mass flow rate determining module 416, and a mass flow rate correction module 418. In some embodiments, the system 400 may further include a fluid pressure determining module 406, a phase difference determining module 408, and an expansion temperature correction module 412.

[0076] The fluid density receiving module 402 receives a fluid density ρ, such as a known fluid density ρref. For example, the fluid density receiving module 402 may perform step 302 described above.

[0077] The fluid temperature receiving module 404 is configured to determine a fluid temperature temp, such as, for example, a known fluid temperature temp. For example, the fluid temperature receiving module 404 can perform step 304 described above.

[0078] The fluid pressure determination module 406 is configured to determine the fluid pressure P. For example, The fluid pressure determination module 406 may perform step 306 described above.

[0079] The phase difference determination module 408 is configured to determine the phase difference ΔT. The phase difference determination module 408 may perform step 308 described above.

[0080] The period determination module 410 is configured to receive the time period T. For example, the period determination module 410 may perform step 310 described above.

[0081] The expansion temperature correction module 412 is configured to determine the expansion temperature correction TFe of the density. For example, the expansion temperature compensation module 412 can perform step 312 described above.

[0082] The Young's modulus of density temperature correction determination module 414 determines the Young's modulus of density temperature correction TFy based on the fluid density ρ, the fluid temperature temp, and the time period Tp. D For example, the density Young's modulus temperature correction determination module 414 may perform step 314 described above.

[0083] The mass flow Young's modulus temperature correction determination module 416 determines the temperature correction constant k and the Young's modulus of density Rate temperature correction TFy D and Young's modulus temperature correction of mass flow rate TFy based on M For example, the mass flow rate Young's modulus temperature correction determination module 416 may perform step 316 described above.

[0084] The mass flow correction module 418 calculates the Young's modulus temperature correction TFy M For example, the mass flow correction module 418 may perform step 318 described above.

[0085] Through testing with liquid nitrogen in a cryogenic calibration facility using a gravimeter, the method and system of the present application have been determined to provide a corrected mass flow value m' with an error of less than 0.10%. Some of the tests performed have provided mass flow rate errors as low as 0.07% and 0.01% for flow meters having flow tubes with diameters of 4 inches or less. The methods and systems described in this application can be extrapolated to larger flow meter sizes, or flow meters having flow tube diameters greater than 4 inches, and can provide very accurate mass flow rate values ​​m' for higher fluid flow rates.

[0086] The methods and systems described herein provide temperature compensation that improves the accuracy of mass flow measurements produced by Coriolis flowmeters at sub-freezing and cryogenic temperatures, and the temperature compensation is stable over time and does not require calibration of the Coriolis flowmeter in a cryogenic calibration facility.

[0087] The detailed description of the above examples is not an exhaustive description of all examples contemplated by the inventors to be within the scope of the present application. Indeed, one skilled in the art will recognize that certain elements of the above examples can be variously combined or deleted to create further examples, which further examples will fall within the scope and teachings of the present application. It will also be apparent to one skilled in the art that the above examples can be combined in whole or in part to create additional examples within the scope and teachings of the present application. Thus, the scope of the present application should be determined from the following claims.

Claims

1. The mass flow value m' measured using the Coriolis flowmeter (100) is calculated using a known flow rate below 0°C. A method for correcting for temperature effects on body temperature, comprising: receiving a known fluid density ρ; receiving the known fluid temperature temp; receiving a time period Tp; Based on the known fluid density ρref, the known fluid temperature temp, and the time period Tp Young's modulus temperature correction TFy D To determine, Temperature correction constant k and Young's modulus temperature correction TFy of the density D Based on the Young's modulus of mass flow rate Degree correction TFy M To determine, and The Young's modulus temperature correction TFy of the mass flow rate M Correcting the mass flow value m' using The method includes:

2. The time period Tp is the measured fluid density ρ indic The method according to claim 1, Law.

3. receiving a phase difference ΔT; Temperature-corrected Young's modulus of density TFy D Determining is further based on the phase difference ΔT, The method of claim 1.

4. receiving a fluid pressure P; Temperature-corrected Young's modulus of density TFy D Determining is further based on the fluid pressure P. The method of claim 1.

5. determining a temperature expansion correction TFe for density; Temperature-corrected Young's modulus of density TFy D But the known temperature temp ref The expansion temperature of the density based on The method according to claim 1 , further comprising determining based on a corrected TFe.

6. 6. The method according to claim 1, wherein the temperature correction constant k is between 0.8 and 1.

2. How to.

7. 5. The method of claim 1, wherein the temperature correction constant k is 1.

8. The Young's modulus temperature correction TFy of the mass flow rate M Correcting the mass flow value m' using Young's modulus temperature correction TFy of the mass M Using the mass error value Error m The method of claim 1 , further comprising determining:

9. 1. A system (400) for correcting mass flow values ​​m' measured using a Coriolis flowmeter (100) for temperature effects at a known fluid temperature temp less than 0° C., comprising: a fluid density receiving module (402) configured to receive a known fluid density ρref; 、 a fluid temperature receiving module (404) configured to receive the known fluid temperature temp; a period determination module (410) configured to receive a time period Tp; Based on the known fluid density ρref, the known fluid temperature temp, and the time period Tp Density Young's modulus temperature correction TFy D a density Young's modulus temperature correction determination module (414) configured to determine Temperature correction constant k and Young's modulus temperature correction TFy of the density D Based on the Young's modulus of mass flow rate Degree correction TFy M a Young's modulus temperature correction determination module (416) configured to determine and The Young's modulus temperature correction TFy of the mass flow rate M a mass flow correction module (418) configured to correct the mass flow value m′ using A system comprising:

10. The fluid density receiving module (402) receives a measured fluid density ρ indic To determine and wherein the period determination module (410) determines the measured fluid density ρ indic Based on 10. The system (400) of claim 9, further configured to determine the time period Tp.

11. a phase difference determination module (408) configured to determine a phase difference ΔT; The density Young's modulus temperature correction determination module (414) determines the Young's modulus temperature correction based on the phase difference ΔT. , Young's modulus temperature correction TFy D The system (400) of claim 9, further configured to determine:

12. Measured fluid pressure P indic a fluid pressure determination module (406) configured to determine The density Young's modulus temperature correction determination module (414) determines the Young's modulus temperature correction based on the fluid pressure P. Temperature-corrected Young's modulus of density TFy D The system (400) of claim 9, further configured to determine:

13. Known temperature ref and further comprising an expansion temperature correction module (412) configured to determine an expansion temperature correction TFe of the density based on The density Young's modulus temperature compensation module (414) calculates the density expansion temperature compensation TFe. Based on the density Young's modulus temperature correction TFy D The system (400) of any of claims 9 to 12, further configured to determine:

14. 14. The method according to claim 9, wherein the temperature correction constant k is between 0.8 and 1.

2. A system (400).

15. 15. The system according to claim 9, wherein the temperature correction constant k is 1. ０）。

16. The mass flow correction module (418) calculates a Young's modulus temperature correction TFy M Using the mass error value Error m The system (400) of any of claims 9 to 15, further configured to determine:

17. 1. Meter electronics (20) for compensating mass flow values ​​m' measured using a meter assembly (10) of a Coriolis flowmeter (100) for temperature effects at a known fluid temperature temp less than 0° C., the meter electronics having a system processor (20b), the system processor (20b) comprising: Taking the known fluid density ρref, receiving the known fluid temperature temp; Receive a time period Tp, Based on the known fluid density ρref, the known fluid temperature temp, and the time period Tp Young's modulus temperature correction TFy D Determine, Temperature correction constant k and Young's modulus temperature correction TFy of the density D Based on the Young's modulus of mass flow rate Degree correction TFy M Determine, and The Young's modulus temperature correction TFy of the mass flow rate M Correct the mass flow value m' using The meter electronics (20) is configured as follows.

18. The time period Tp is the measured fluid density ρ indic The method of claim 17, wherein the Meter electronics (20).

19. The system processor (20b) is further configured to receive the phase difference ΔT. And, Temperature-corrected Young's modulus of density TFy D determining the phase difference ΔT based on the phase difference ΔT; The meter electronics (20) of claim 17.

20. The system processor (20b) is further configured to receive a fluid pressure P. And, Temperature-corrected Young's modulus of density TFy D is further based on the fluid pressure P. The on-board meter electronics (20).

21. The system processor (20b) further determines a density expansion temperature correction TFe. It is composed of Temperature-corrected Young's modulus of density TFy D But the known temperature temp ref The expansion temperature of the density based on 21. The meter according to claim 17, further determined based on a correction TFe. Electronic equipment (20).

22. 22. The method according to claim 17, wherein the temperature correction constant k is between 0.8 and 1.

2. The meter electronics (20) as described above.

23. 23. The meter electronic device according to claim 17, wherein the temperature correction constant k is 1. Equipment (20).

24. The Young's modulus temperature correction TFy of the mass flow rate M Correcting the mass flow value m' using Young's modulus temperature correction TFy of the mass M Using the mass error value Error m The meter electronics (20) of any of claims 17 to 23, further comprising determining:

Images