Method, system, and electronic device for calibrating a Coriolis flowmeter measurement
By determining and applying Young's modulus temperature correction in Coriolis flowmeter, the problem of large mass flow measurement error at low temperatures is solved, and higher precision flow measurement is achieved.
Patent Information
- Application Number
- CN202080102384.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-06-24
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2040-06-24
AI Technical Summary
Existing Coriolis flowmeters are difficult to provide accurate mass flow measurements at temperatures below 0°C, and the stiffness changes of low-temperature flow tubes are difficult to effectively characterize, resulting in large measurement errors.
The mass flow value is then corrected by receiving known fluid density, temperature and time periods.
Improved accuracy of mass flow values measured by Coriolis flowmeters under zero and low temperature conditions, with an error of less than 0.10%, and no additional calibration is required in the cryogenic calibration facility.
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Figure CN115735101B_ABST
Abstract
Description
Technical Field
[0001] This application relates to Coriolis flowmeters and, more particularly, to correcting Coriolis flowmeter measurements for temperature effects. Background Art
[0002] A Coriolis mass flowmeter utilizes Coriolis forces induced by a fluid flowing through one or more vibrating tubes to measure mass flow rate. Figure 1 An example Coriolis flowmeter 100 including a metering assembly 10 and metering electronics 20 is depicted. The metering assembly 10 responds to changes in the process fluid flow rate. The metering electronics 20 are connected to the metering assembly 10 via wires 102 and provide density, volumetric flow rate, and mass flow rate information, as well as other information, to an operator via a metering electronics interface 26.
[0003] The metering assembly 10 includes a manifold 150 and a manifold 150', flanges 103 and 103', two parallel flow tubes 130 and 130', a driver 180, and velocity pickoff sensors 170L and 170R. The flow tubes 130 and 130' are bent at two symmetric locations along their lengths and are substantially parallel throughout their lengths. Struts 140 and 140' are used to define the axes about which each flow tube oscillates.
[0004] When the flanges 103 and 103' are connected to a process line (not shown) via an inlet end 104 and an outlet end 104', process fluid enters the inlet end 104 of the meter through the flange 103 and is routed through the manifold 150. The manifold 150 splits the process fluid and routes the process fluid through the flow tubes 130 and 130'. After leaving the flow tubes 130 and 130', the process fluid recombines into a single stream through the manifold 150' and is routed to the outlet end 104', which is connected to the process line (not shown) through the flange 103'.
[0005] The two flow tubes 130 and 130' are driven in opposite directions by the driver 180 in a first out-of-phase bending mode of the flowmeter. The driver 180 can include any of a number of well-known arrangements, such as a magnet mounted to the flow tube 130' and a reaction coil mounted to the flow tube 130, and an alternating current is passed through this arrangement to vibrate the two flow tubes. A suitable driver voltage is applied to the driver 180 by the metering electronics 20. In other embodiments, the Coriolis flowmeter 100 can include more than one driver 180, thus providing a multi-input arrangement that can generate other bending modes.
[0006] Although the Coriolis flowmeter 100 depicts a dual-bend flow tube design, this is not intended to be limiting. Those skilled in the art will understand that other examples of Coriolis flowmeters 100 may include one or any number of flow tubes. Those skilled in the art will also understand that other Coriolis flowmeters may include straight flow tubes or any other configuration.
[0007] The metering electronics 20 provides a drive signal to the driver 180 via the wire 102 to vibrate the flow tube 130 and the flow tube 130'. The metering electronics 20 receives a left velocity signal and a right velocity signal from the velocity pick-up sensor 170L and the velocity pick-up sensor 170R via the wire 102, and the left velocity signal and the right velocity signal can be used to calculate the mass flow rate, volume flow rate, and / or density information of the flow passing through the metering assembly 10.
[0008] The left velocity signal and the right velocity signal from the pick-up sensors 170L and 170R are used to determine the phase difference ΔT representing the Coriolis force on the flow tube between the pick-up sensor 170L and the pick-up sensor 170R. The phase difference ΔT is used to determine the mass flow value using Equation 1
[0009]
[0010] where the flow calibration factor FCF and the zero offset ΔT 0 are determined during factory calibration. The FCF captures the stiffness of one or more of the flow tubes 130, 130', which is proportional to the mass flow rate of the fluid flowing through the flow tubes. The FCF is determined by flowing water under ambient conditions through the Coriolis mass flowmeter and comparing the indicated mass with the mass measured by a reference flowmeter.
[0011] The mass flow measurement of the Coriolis flowmeter 100 is typically corrected after installation at the customer site to account for differences between the customer site and the factory environmental conditions. For example, changes in temperature and fluid pressure can change the stiffness of the flow tubes 130, 130', which may introduce errors in the meter mass flow and density measurements.
[0012] The temperature correction required for mass flow and density measurements above 0 °C is different from that required for temperatures below 0 °C. The temperature correction for the measured mass flow value due to the change in stiffness caused by the Young's modulus at temperatures above 0 °C is approximately linear. For temperatures below 0 °C, the correction to the mass flow measurement value is typically better represented by a polynomial equation.
[0013] It has been empirically observed that for temperatures between 0°C and 50°C, the temperature correction for density measurement is different from the temperature correction based on mass flow measurement. However, due to the limitations of the flow rates available in cryogenic calibration facilities, it is difficult to characterize the change in flow tube stiffness based on Young's modulus at temperatures below 0°C. To date, for smaller flow meters or flow meters with flow tubes 4 inches or less in diameter, only empirical data has been available to characterize the temperature-based change in flow tube stiffness.
[0014] More accurate mass flow measurements are needed at sub-zero and cryogenic temperatures. One possible application is the high volume flow of liquefied natural gas at a temperature of -160°C.
[0015] It is highly desirable to provide more accurate fluid measurements using a Coriolis flow meter at sub-zero and cryogenic temperatures. Summary of the Invention
[0016] A method is provided for correcting the mass flow value measured using a Coriolis flow meter for the temperature effect when the known fluid temperature temp is below 0°C. The method includes: receiving the known fluid density ρ ref ; receiving the known fluid temperature temp; receiving the time period Tp; determining the Young's modulus temperature correction TFy for density based on the known fluid density ρ ref , the known fluid temperature temp, and the time period Tp; determining the Young's modulus temperature correction TFy for mass flow based on the temperature correction constant k and the Young's modulus temperature correction TFy for density D ; and using the Young's modulus temperature correction TFy for mass flow D to correct the mass flow value. M M
[0017] A system is provided for correcting the mass flow value measured using a Coriolis flow meter for the temperature effect when the known fluid temperature temp is below 0°C. The system includes: a fluid density receiving module configured to receive the known fluid density ρ ref ; a fluid temperature receiving module configured to receive the known fluid temperature temp; a time period determination module configured to receive the time period Tp; a Young's modulus temperature correction determination module for density configured to determine the Young's modulus temperature correction TFy for density based on the known fluid density ρ ref , the known fluid temperature temp, and the time period Tp. D ; A Young's modulus temperature correction determination module for mass flow, which is configured to determine the Young's modulus temperature correction TFy for mass flow based on the temperature correction constant k and the Young's modulus temperature correction TFy for density D to determine the Young's modulus temperature correction TFy for mass flow M ; and a mass flow correction module, which is configured to use the Young's modulus temperature correction TFy for mass flow M to correct the mass flow value
[0018] A metering electronic device is provided for correcting the mass flow value measured by a metering component using a Coriolis flowmeter for the temperature effect when the known fluid temperature temp is below 0 °C The metering electronic device including a system processor is configured to: receive the known fluid density ρ ref ; receive the known fluid temperature temp; receive the time period Tp; determine the Young's modulus temperature correction TFy for density based on the known fluid density ρ ref , the known fluid temperature temp and the time period Tp D ; determine the Young's modulus temperature correction TFy for mass flow based on the temperature correction constant k and the Young's modulus temperature correction TFy for density D to determine the Young's modulus temperature correction TFy for mass flow M ; and use the Young's modulus temperature correction TFy for mass flow M to correct the mass flow value
[0019] each aspect
[0020] According to another aspect, the time period Tp can be determined based on the measured fluid density ρ indic to determine.
[0021] According to another aspect, the method may further include: receiving the phase difference ΔT, and determining the Young's modulus temperature correction TFy for density D may also be based on the phase difference ΔT.
[0022] According to another aspect, the method may further include: receiving the fluid pressure P, and the Young's modulus temperature correction TFy for density D may also be based on the fluid pressure P.
[0023] According to another aspect, the method may further include: determining the expansion temperature correction TFe for density, and the Young's modulus temperature correction TFy for density D may also be determined based on the expansion temperature correction TFe for density, and the expansion temperature correction TFe for density is based on the known temperature temp ref .
[0024] According to another aspect, the temperature correction constant k can be between 0.8 and 1.2.
[0025] According to another aspect, the temperature correction constant k can be 1.
[0026] According to another aspect, the Young's modulus temperature correction TFy for mass flow rate is used M to correct the mass flow rate value It may further include using the Young's modulus temperature correction TFy for mass M to determine the mass error value Error m .
[0027] According to another aspect, the fluid density receiving module may further be configured to determine the measured fluid density ρ indic , and the time period determining module is further configured to determine the time period Tp based on the measured fluid density ρ indic .
[0028] According to another aspect, the system may further include: a phase difference determining module configured to determine the phase difference ΔT, and the Young's modulus temperature correction determining module for density may further be configured to determine the Young's modulus temperature correction TFy for density based on the phase difference ΔT D .
[0029] According to another aspect, the system may further include: a fluid pressure determining module configured to determine the measured fluid pressure P indic , and the Young's modulus temperature correction determining module for density may further be configured to determine the Young's modulus temperature correction TFy for density based on the fluid pressure P D .
[0030] According to another aspect, the system may further include: an expansion temperature correction module configured to determine the expansion temperature correction TFe for density based on the known temperature temp ref , and the Young's modulus temperature correction module for density may further be configured to determine the Young's modulus temperature correction TFy for density based on the expansion temperature correction TFe for density D .
[0031] According to another aspect, the temperature correction constant k can be between 0.8 and 1.2.
[0032] According to another aspect, the temperature correction constant k can be 1.
[0033] According to another aspect, the mass flow rate correction module may further be configured to use the Young's modulus temperature correction TFy for mass M to determine the mass error value Error m .
[0034] According to another aspect, the time period Tp can be based on the measured fluid density ρ indic to be determined.
[0035] According to another aspect, the system processor can also be configured to receive the phase difference ΔT, and determine the Young's modulus temperature correction TFy for density D can also be based on the phase difference ΔT.
[0036] According to another aspect, the system processor can also be configured to receive the fluid pressure P, and the Young's modulus temperature correction TFy for density D can also be based on the fluid pressure P.
[0037] According to another aspect, the system processor can also be configured to determine the expansion temperature correction TFe for density, and the Young's modulus temperature correction TFy for density D can also be determined based on the expansion temperature correction TFe for density, and the expansion temperature correction TFe for density is based on the known temperature temp ref .
[0038] According to another aspect, the temperature correction constant k can be between 0.8 and 1.2.
[0039] According to another aspect, the temperature correction constant k can be 1.
[0040] According to another aspect, use the Young's modulus temperature correction TFy for mass flow rate M to correct the mass flow rate value can also include using the Young's modulus temperature correction TFy for mass M to determine the mass error value Error m . Description of the Drawings
[0041] In all the drawings, the same reference numerals denote the same elements. The drawings are not necessarily drawn to scale.
[0042] Figure 1 depicts the Coriolis flowmeter 100;
[0043] Figure 2 depicts the system 200 according to an embodiment;
[0044] Figure 3 depicts the method 300 according to an embodiment; and
[0045] Figure 4 depicts the system 400 according to an embodiment. Detailed Description
[0046] Figures 2 to 4 The following description depicts specific examples to teach those skilled in the art how to implement and use the best mode of the present application. For the purpose of teaching the principles of the invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand variations from these examples that fall within the scope of the present application. Those skilled in the art will understand that the features described below can be combined in various ways to form multiple variations of the present application. Therefore, the present application is not limited to the specific examples described below, but is defined only by the claims and their equivalents.
[0047] Figure 2 A system 200 according to an embodiment is depicted. The system 200 can be used to perform temperature correction on the mass flow rate values measured using a Coriolis flowmeter for the temperature effect when the fluid temperature is below 0°C. For example, the system 200 can be used to provide temperature correction based on temperature for the mass flow rate values measured using a Coriolis flowmeter, such as temperature correction due to Young's modulus, elastic modulus, thermal expansion, or pressure effects.
[0048] The system 200 includes a Coriolis flowmeter 100, metering electronics 20, and a process conduit 206. The process conduit 206 conveys the fluid flow to be measured by the Coriolis flowmeter 100.
[0049] The metering electronics 20 can be used to generate the mass flow rate values of the fluid measured using the metering assembly 10 of the Coriolis flowmeter 100 or to perform temperature correction on the mass flow rate values obtained using the metering assembly 10. The metering electronics 20 includes a memory 20a, a system processor 20b, and an interface 20c.
[0050]
[0051] The memory 20a includes an electronically readable medium or a computer-readable medium configured to store computer program instructions. In an example, the memory 20a can include a non-transitory medium. The computer program instructions stored on the memory 20a can execute some or all of the steps described for the method 300, or execute some or all of the modules of the system 400.
[0052] The interface 20c is configured to communicate with the metering assembly 10 of the Coriolis flowmeter 100. The interface 20c may be configured to communicate with devices external to the electronic device 20 (e.g., a pressure sensor, a temperature sensor, or any other sensor known to those skilled in the art).
[0053] In an embodiment, the system 200 may include an additional measurement device 208. In an embodiment, the additional measurement device 208 may include a device capable of providing density measurements, such as a densitometer, a gas chromatograph, an additional Coriolis meter, or any other type of measurement device known to those skilled in the art. In an embodiment, the additional measurement device 208 may include a corresponding metering electronic device 204, as Figure 2 depicted. Like the metering electronic device 20, the metering electronic device 204 may include a memory 204a, a system processor 204b, and an interface 204c. However, in other embodiments, the additional measurement device 208 may directly provide signals and information to the interface 20c of the metering electronic device 20.
[0054] In other embodiments, the system 200 may include a server 202. In an embodiment, the server 202 may communicate with the interface 20c of the metering electronic device 20 and / or the interface 204c of the metering electronic device 204. Any part of the steps described with respect to the method 300 or the modules described with respect to the system 400 may be stored or executed on the server 202.
[0055] Figure 3 Method 300 according to an embodiment is depicted. Method 300 may be used to correct the mass flow rate value measured using a Coriolis flowmeter ref for temperature effects when the known fluid temperature temp is below 0°C. For example, method 300 may be used to provide a measurement correction based on temperature for the mass flow rate value measured using the Coriolis flowmeter 100 such as a measurement correction for variations associated with changes in Young's modulus, elastic modulus, thermal expansion, or pressure effects.
[0056] Method 300 begins with step 302. In step 302, a known fluid density ρ ref is received. Method 300 proceeds to step 304. In step 304, a known fluid temperature temp is received. Due to the nature of the fluid being measured, the known fluid density ρ ref and the known fluid temperature temp may be well understood.
[0057] Method 300 proceeds to step 310. In step 310, a time period Tp is received. The time period Tp is the time period of the vibrating flow tubes 130, 130'.
[0058] In an embodiment, the time period Tp can be directly measured using a vibration sensor coupled to the flow tubes 130, 130', the vibration sensor including one or both of, for example, the left velocity pick-up sensor 170L and the right velocity pick-up sensor 170R of the Coriolis flowmeter 100.
[0059] However, in other embodiments of step 310, the time period Tp can be indirectly determined based on the measured fluid density ρ indic 、phase difference ΔT, and fluid pressure P as follows.
[0060] In the method of indirectly determining the time period Tp, step 310 can further include step 306 and step 308. In step 306, the fluid pressure P can be received. In an embodiment, the fluid pressure P can include the fluid pressure determined using a pressure transducer located just upstream or downstream of the Coriolis flowmeter 100 in the process conduit 206. However, in other embodiments, the fluid pressure P can include the pressure measurement inside the Coriolis flowmeter 100, or any other fluid pressure measurement known to those skilled in the art. In an embodiment, the fluid pressure P can include a known or estimated fluid pressure.
[0061] In step 308, the phase difference ΔT can be received. In an embodiment, the velocity pick-up sensors 170L and 170R of the Coriolis flowmeter 100 can be used to determine the phase difference ΔT. However, in other embodiments, as will be understood by those skilled in the art, the measured mass flow rate value FCF, combined temperature factor TF, and fluid temperature temp can be used to indirectly determine the phase difference ΔT.
[0062] In an embodiment, the measured fluid density ρ indic can be measured using a densitometer. For example, the measured fluid density ρ indic can be received from an additional measurement device 208 in the system 200, and the additional measurement device 208 can include a densitometer. In other embodiments, the additional measurement device 208 in the system 200 can include a gas chromatograph that can provide the measured fluid density ρ indic value.
[0063] The Coriolis flowmeter 100 is typically calibrated at a temperature between 20 °C and 30 °C under factory conditions. In many cases, two fluids such as ambient air and water are used to calibrate the Coriolis flowmeter by determining the mass flow rate value and the measured fluid density ρ indic value for each fluid. Using the mass flow rate value and the measured fluid density ρindic From these measured values, the calibration constant K can be determined 1 and K 2 , with one constant for each respective fluid.
[0064] The calibration constant K can then be used via Equation 2 and Equation 3 1 and K 2 to calculate the calibration value C effective for a temperature of 0°C and a pressure of 0 bar 1 and C 2 . The calibration value C 1 is proportional to the moment of inertia and inversely proportional to the flow area of the flow tubes 130, 130':
[0065]
[0066] The calibration value C 2 is proportional to the mass of the material of the flow tubes 130, 130' divided by the fluid volume:[[]]
[0067]
[0068] In Equation 2 and Equation 3, D 1 is the outer diameter of the flow tubes 130, 130', and D 2 is the inner diameter of the flow tubes 130, 130'.
[0069] The measured fluid density ρ indic can be determined using Equation 4:[[]]
[0070]
[0071] In Equation 4, TF d is the combined temperature correction factor for density. As will be understood by those skilled in the art, FD is a constant for correcting the fluid density ρ measured under flow conditions indic . In Equation 4, pcd is the pressure correction for density.[[]]
[0072] Equation 4 can be rearranged to Equation 5:[[]]
[0073]
[0074] In an embodiment, the square of the time period T p 2 can be determined using Equation 5 based on the measured fluid density ρ indic , the fluid pressure P, and the phase difference ΔT. However, in other embodiments, the FD*(ΔT) 2 *10 -9 term in Equation 5 representing the correction to the measured fluid density ρ indicThe flow impact can be very small and can thus be ignored. The pressure correction pcd for density can also be small and the equation 5 can thus be further simplified by setting pcd equal to zero. This can provide an
[0075] Simplified implementation of equation 6:
[0076]
[0077] According to equation 6, the square of the time period T can be determined based on the measured fluid density ρ indic to determine the square of the time period T p 2 .
[0078] Method 300 proceeds to step 314. In step 314, the Young's modulus temperature correction TFy for density is determined D . The Young's modulus is affected by the material expansion and geometric shape change of the flow tube due to temperature and (to a lesser extent) due to pressure.
[0079] In an implementation, the Young's modulus temperature correction TFy for density D can be determined using any method known to those skilled in the art. However, in other implementations, the Young's modulus temperature correction TFy for density D can be determined based on the known fluid density ρ ref , fluid temperature temp, and time period Tp.
[0080] For example, the known fluid density ρ ref is related to the Young's modulus E(temp,P) via an exact theory according to equation 7:
[0081]
[0082] In equation 7, FD is the flow impact on density, L is the length of the flow tubes 130, 130', D o is the outer diameter of the flow tubes 130, 130', and D i is the inner diameter of the flow tubes 130, 130'. When the temperature temp is 0 °C and the fluid pressure P is 0 bar, equation 7 can be rewritten as equation 8:
[0083]
[0084] where PF c1 is the pressure factor representing the combination of the Young's modulus change and geometric shape change due to fluid pressure, PF c1 = 1 + pc c1 * P, where pc c1 is a constant C 1The pressure coefficient. In Equation 8, PF C2 is the pressure factor related to the change in fluid volume due to pressure, PF C2 = 1 + pc c2 *P, where pc c2 is the pressure coefficient of constant C 2 For example, for the Micro Motion flowmeter of model CMF400, pc c1 is 3.45 * 10 -5 , pc c2 is 0.99 * 10 -5 , and the pressure effect is -0.145 kg / m 3 / bar.
[0085] In Equation 8, TF y is the temperature factor due to Young's modulus. At low temperatures, the temperature factor TF y due to Young's modulus can be non - linear. For example, in the article "Stainless steel elastic constants at low temperatures" in the Journal of Applied Physics written by Mr. H.M. Ledbetter in March 1981, a polynomial of Equation 9 was proposed for stainless steel at low temperatures:
[0086] TF y = 1 - tc y *temp - 3.5 * 10 -7* (temp) 2 - 2 * 10 -9* (temp) 3 - 1.3 * 10 -11* (temp) 4 . (Equation 9)
[0087] In Equation 9, temp represents the temperature, which can be a known or measured temperature. In the implementation of step 314, the known temperature temp ref can be used to determine the temperature factor TF y due to Young's modulus.
[0088] In Equation 8, the known fluid density ρ ref also depends on TFe, that is, the expansion temperature correction for density. The expansion temperature correction TFe for density can be determined by any method known to those skilled in the art. In an implementation, step 314 may further include step 312. In step 312, the expansion temperature correction TFe for density can be determined based on empirical data related to the expansion of the flow tube material.
[0089] In an embodiment, the expansion temperature correction TFe for density can be non-linear. For example, the article "Low temperature thermal expansion of iron-chromium-nickel alloys of different stabilities" published in February 1978 provides the following polynomial equation 10, which describes the temperature correction for thermal expansion at low temperatures:
[0090] TF e = 1 + 16.061 * 10 -6 * temp + 5.65 * 10 -9 * temp 2 - 6.007 * 10 -11 * temp 3 .
[0091] (Equation 10)
[0092] In an embodiment of step 312, the known temperature temp ref can be used to determine the expansion temperature correction TFe for density.
[0093] Using the known fluid density ρ ref , phase difference ΔT, fluid pressure P, known fluid temperature temp ref and time period Tp, the Young's modulus temperature correction TF for density can thus be determined via Equation 11 yd :
[0094]
[0095] Because the Young's modulus of the flow tube affects the vibration of the flow tubes 130, 130', the mass flow measurement and the fluid density measurement ρ will both be affected by changes in the Young's modulus. The vibration of the flow tube is a function of the material properties of the flow tubes 130, 130' and the flow tubes 130, 130' are typically made of steel.
[0096] However, in other embodiments, the flow effect on the fluid density represented by the FD*(ΔT) 2 * 10 -9 term in Equation 11 can be very small and can therefore be ignored. Additionally, the pressure factors of C1, namely PFC1 and PFC2, can also represent the Young's modulus temperature correction TF for density ydMinor changes. Setting the flow effect FD on the fluid density to zero and setting the pressure factors PFC1 and PFC2 to 1 can provide the Young's modulus temperature correction TF for density in Equation 12 yd A simplified representation of:
[0097]
[0098] According to Equation 12, the Young's modulus temperature correction TF for density yd can be determined based only on the known fluid density ρ ref , the known fluid temperature temp ref and the time period Tp.
[0099] Once the Young's modulus temperature correction TF for density is determined yd , method 300 can proceed to step 316. In step 316, the Young's modulus temperature correction TFy for mass flow is determined based on the temperature correction constant k multiplied by the Young's modulus temperature correction TF for density D , as represented by Equation 13: M TF
[0100] TF ym = k * TF yD (Equation 13)
[0101] The Young's modulus temperature correction TFy for mass flow M is typically related to the torque in the flow tube, while the Young's modulus temperature correction TFy for density D is typically related to the bending in the flow tube. Initial tests using a flowmeter with a stainless steel tube shaped in a "U" configuration in a calibration laboratory have indicated that these temperature corrections are substantially similar numerically. Thus, in an embodiment, the temperature correction constant k can be set to 1. However, it is possible that future tests using more sensitive measurements, different tube materials, and / or different tube geometries may reveal that the Young's modulus temperature correction TFy for mass flow M and the Young's modulus temperature correction TFy for density D are numerically different. Thus, in other embodiments, the temperature correction constant k can be determined to be any number other than 1. In a non-limiting example, k can be set to a value between 0.8 and 1.2.
[0102] Once the Young's modulus temperature correction TFy for mass flow is determined M , method 300 can proceed to step 320. In step 320, the Young's modulus temperature correction TFy for mass flow is used MThe mass flow rate value determined using Equation 1 with the Coriolis flowmeter 100 is corrected. In an embodiment, a Young's modulus temperature correction TFy for mass flow rate M may be used to correct the mass flow rate value by any method known to those skilled in the art
[0103] In an embodiment, step 320 may further include step 318. In step 318, an expansion temperature correction TFe for density and a Young's modulus temperature correction TFy for mass determined via steps 312 and 316 M are used to determine a mass error value Error m :
[0104]
[0105] In Equation 14:
[0106] Q m-zero-cal is the zero-flow mass flow rate measured during factor calibration using a calibration fluid;
[0107] Q m-cal is the mass flow rate measured during factory calibration using a calibration fluid;
[0108] PF m-real-cal is the true pressure factor determined during calibration;
[0109] PF m-cal is the applied pressure factor determined during calibration;
[0110] PF m-oper is the applied pressure factor determined during operation;
[0111] PF m-real-oper is the true pressure factor determined during operation;
[0112] Error cal％ is the metering error determined during calibration;
[0113] MF m-cal is the metering-specific mass factor determined during calibration;
[0114] MF m-oper is the metering-specific mass factor determined during operation;
[0115] TF e-cal is the expansion temperature correction for density determined during calibration; and
[0116] TFy m-calis the mass temperature correction for density determined during calibration.
[0117] The first part of Equation 14 comes from calibration and reflects the mass error value Error at 0 °C and 0 bar m , and the second part of Equation 14 comes from the operation in the application and reflects the error from 0 °C and 0 bar to the 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:
[0118]
[0119] In an embodiment, a metering factor MF can be determined to use Equation 16 for the mass flow rate value measured using the Coriolis flowmeter 100 for correction:
[0120]
[0121] Then the corrected mass flow rate value can be determined by multiplying the measured mass flow rate value by the metering factor MF
[0122] Figure 4 System 400 is depicted. In an embodiment, system 400 can be used to correct the mass flow rate value measured using the Coriolis flowmeter 100 for the temperature effect when the fluid temperature temp is below 0 °C. System 400 includes a fluid density receiving module 402, a fluid temperature receiving module 404, a time period determining module 410, a Young's modulus temperature correction determining module 414 for density, a Young's modulus temperature correction determining module 416 for mass flow rate, and a mass flow rate correction module 418. In an embodiment, system 400 may further include a fluid pressure determining module 406, a phase difference determining module 408, and an expansion temperature correction module 412.
[0123] The fluid density receiving module 402 is configured to determine the fluid density ρ, such as a known fluid density ρ ref . For example, the fluid density receiving module 402 can perform step 302 described above.
[0124] The fluid temperature receiving module 404 is configured to determine the fluid temperature temp, such as a known fluid temperature temp. For example, the fluid temperature receiving module 404 can perform step 304 as described above.
[0125] The fluid pressure determining module 406 is configured to determine the fluid pressure P. For example, the fluid pressure determining module 406 can perform step 306 as described above.
[0126] The phase difference determination module 408 is configured to determine a phase difference ΔT. For example, the phase difference determination module 408 may perform step 308 as described above.
[0127] The time period determination module 410 is configured to receive a time period Tp. For example, the time period determination module 410 may perform step 310 as described above.
[0128] The expansion temperature correction module 412 is configured to determine an expansion temperature correction TFe for density. For example, the expansion temperature correction module 412 may perform step 312 as described above.
[0129] The Young's modulus temperature correction determination module 414 for density is configured to determine a Young's modulus temperature correction TFy for density based on the fluid density ρ, the fluid temperature temp, and the time period Tp D For example, the Young's modulus temperature correction determination module 414 for density may perform step 314 as described above.
[0130] The Young's modulus temperature correction determination module 416 for mass flow is configured to determine a Young's modulus temperature correction TFy for mass flow based on a temperature correction constant k and the Young's modulus temperature correction TFy for density D to determine a Young's modulus temperature correction TFy for mass flow M For example, the Young's modulus temperature correction determination module 416 for mass flow may perform step 316 as described above.
[0131] The mass flow correction module 418 is configured to use the Young's modulus temperature correction TFy for mass flow M to correct the mass flow value For example, the mass flow correction module 418 may perform step 318 as described above.
[0132] Tests of liquid nitrogen performed at a cryogenic calibration facility using a weighing scale have determined that the methods and systems of the present application provide corrected mass flow values with an error of less than 0.10% Some tests performed by the applicant have provided mass flow errors as low as 0.07% and 0.01% for flow meters having flow tubes with a diameter of 4 inches or less. The methods and systems described in the present application can be extrapolated to larger meter sizes or meter sizes having a flow tube diameter greater than 4 inches to provide very accurate mass flow values for higher fluid flow rates
[0133] The methods and systems described herein provide temperature correction that improves the accuracy of mass flow rate measurements generated using a Coriolis flow meter at sub-zero and cryogenic temperatures. The temperature correction is stable over time and does not require calibration of the Coriolis flow meter at a cryogenic calibration facility.
[0134] The detailed description of the above examples is not an exhaustive description of all examples contemplated by the inventors within the scope of this application. In fact, those skilled in the art will recognize that certain elements of the above examples can be combined or eliminated in different ways to create other examples, and these other examples fall within the scope and teachings of this application. It will also be apparent to those of ordinary skill in the art that the above examples can be combined in whole or in part to yield additional examples within the scope and teachings of this application. Accordingly, the scope of this application should be determined by the appended claims.
Claims
1. A method for correcting the mass flow rate value measured using a Coriolis flowmeter (100) for the temperature effect when the known fluid temperature temp is below 0 °C wherein the method Comprising: Receive a known fluid density ρ ref ; Receiving the known fluid temperature temp; Receiving the time period Tp; Based on the known fluid density ρ ref , the known fluid temperature temp, and the time period Tp, determine the Young's modulus temperature correction factor TFy for determining the density D ; Based on the temperature correction constant k and the Young's modulus temperature correction factor TFy for determining density D to determine the Young's modulus temperature correction factor TFy for determining mass flow rate M ; And Use the Young's modulus temperature correction factor TFy for determining the mass flow rate M to correct the mass flow rate value Among them, C 1 and C 2 is the calibration value valid for a temperature of 0 °C and a pressure of 0 bar for said known fluid density ρ; and ref is the calibration value valid for a temperature of 0 °C and a pressure of 0 bar for said known fluid density ρ; and TFe is the expansion temperature correction factor for determining density.
2. The method according to claim 1, wherein, The time period Tp is based on the measured fluid density ρ indic and is determined.
3. The method according to claim 1, further Comprising: Receiving the phase difference ΔT, and wherein, determining the Young's modulus temperature correction factor TFy for determining the density D is further based on the phase difference ΔT.
4. The method according to claim 1, further Comprising: Receiving the fluid pressure P, and wherein, the Young's modulus temperature correction factor TFy for determining the density D is also based on the fluid pressure P.
5. The method according to any one of claims 1 to 4, wherein, The expansion temperature correction factor TFe for determining density is based on the known temperature temp ref .
6. The method according to any one of claims 1 to 4, wherein, The temperature correction constant k is between 0.8 and 1.
2.
7. The method according to any one of claims 1 to 4, wherein, The temperature correction constant k is 1.
8. The method according to any one of claims 1 to 4, wherein, Use the Young's modulus temperature correction factor TFy for determining the mass flow rate M to correct the mass flow rate value Further comprising: Use the Young's modulus temperature correction factor TFy for determining quality M to determine the mass error value Error m .
9. A system (400) for correcting the mass flow rate value measured using a Coriolis flowmeter (100) for the temperature effect when the known fluid temperature temp is below 0 °C wherein the system (400) Comprising: A fluid density receiving module (402) configured to receive a known fluid density ρ ref ; A fluid temperature receiving module (404) configured to receive the known fluid temperature temp; A time period determination module (410) configured to receive the time period Tp; Young's modulus temperature correction determination module (414) for density, which is configured to determine the Young's modulus temperature correction factor TFy for determining density based on the known fluid density ρ ref , the known fluid temperature temp, and the time period Tp D ; A Young's modulus temperature correction determination module (416) for mass flow rate, which is configured to determine a Young's modulus temperature correction factor TFy for determining mass flow rate based on a temperature correction constant k and the Young's modulus temperature correction factor TFy for determining density D to determine a Young's modulus temperature correction factor TFy for determining mass flow rate M ; and A mass flow rate correction module (418) configured to use the Young's modulus temperature correction factor TFy for determining the mass flow rate M to correct the mass flow rate value Among them, C 1 and C 2 is the calibration value valid for a temperature of 0 °C and a pressure of 0 bar for said known fluid density ρ; and ref for a temperature of 0 °C and a pressure of 0 bar; and TFe is the expansion temperature correction factor for determining density.
10. The system (400) according to claim 9, wherein, The fluid density receiving module (402) is further configured to determine the measured fluid density ρ indic , and the time period determining module (410) is further configured to determine the time period Tp based on the measured fluid density ρ indic to determine the time period Tp.
11. The system (400) according to claim 9, further Comprising: A phase difference determination module (408) configured to determine the phase difference ΔT, and Among them, the Young's modulus temperature correction determination module (414) for density is further configured to determine the Young's modulus temperature correction factor TFy for determining density based on the phase difference ΔT D .
12. The system (400) according to claim 9, the system further Comprising: Fluid pressure determination module (406), which is configured to determine the measured fluid pressure P indic , and Wherein, the Young's modulus temperature correction determination module (414) for density is further configured to determine the Young's modulus temperature correction factor TFy for determining density based on the fluid pressure P D .
13. The system (400) according to any one of claims 9 to 12, wherein, The system (400) further comprises: Expansion temperature correction module (412), which is configured to determine the expansion temperature correction factor TFe for determining density based on a known temperature temp ref 14. The system (400) according to any one of claims 9 to 12, wherein, The temperature correction constant k is between 0.8 and 1.
2.
15. The system (400) according to any one of claims 9 to 12, wherein, The temperature correction constant k is 1.
16. The system (400) according to any one of claims 9 to 12, wherein, The mass flow rate correction module (418) is further configured to use the Young's modulus temperature correction factor TFy for determining mass M to determine a mass error value Error m .
17. A metering electronic device (20) for correcting a mass flow value measured by a metering assembly (10) using a Coriolis flowmeter (100) for the temperature influence when a known fluid temperature temp is below 0 °C, the metering electronic device including a system processor (20b) configured to: perform the correction, the system processor (20b) being configured to: Receive a known fluid density ρ ref ; Receiving the known fluid temperature temp; Receiving the time period Tp; Based on the known fluid density ρ ref and the known fluid temperature temp and the time period Tp, a Young's modulus temperature correction factor TFy for determining density is determined D ; Based on the temperature correction constant k and the Young's modulus temperature correction factor TFy for determining density D to determine the Young's modulus temperature correction factor TFy for determining mass flow rate M ; and Use the Young's modulus temperature correction factor TFy for determining the mass flow rate M to correct the mass flow rate value wherein, C 1 and C 2 is a calibration value valid for a temperature of 0 °C and a pressure of 0 bar for said known fluid density ρ; and ref for a temperature of 0 °C and a pressure of 0 bar; and TFe is the expansion temperature correction factor for determining density.
18. The metering electronic device (20) according to claim 17, wherein, The time period Tp is determined based on the measured fluid density ρ indic determined.
19. The metering electronic device (20) according to claim 17, wherein, The system processor (20b) is further configured to receive the phase difference ΔT, and Among them, the Young's modulus temperature correction factor TFy for determining the density is determined D also based on the phase difference ΔT.
20. The metering electronic device (20) according to claim 17, wherein, The system processor (20b) is further configured to: Receiving the fluid pressure P, and wherein, the Young's modulus temperature correction factor TFy for determining density D is further based on the fluid pressure P.
21. The metering electronic device (20) according to any one of claims 17 to 20, wherein, The system processor is further configured to: Determine the expansion temperature correction factor TFe for determining density, and Among them, the expansion temperature correction factor TFe for determining density is based on the known temperature temp re f.
22. The metering electronic device (20) according to any one of claims 17 to 20, wherein, The temperature correction constant k is between 0.8 and 1.
2.
23. The metering electronic device (20) according to any one of claims 17 to 20, wherein, The temperature correction constant k is 1.
24. The metering electronic device (20) according to any one of claims 17 to 20, wherein, Use the Young's modulus temperature correction factor TFy for determining the mass flow rate M to correct the mass flow rate value It further includes: Use the Young's modulus temperature correction factor TFy for determining the quality M to determine the mass error value Error m .