Compensating for fluid flow effects on a viscosity meter
Patent Information
- Application Number
- PCT/US2025/016595
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-20
- Publication Date
- 2026-08-27
Smart Images
Figure US2025016595_27082026_PF_FP_ABST
Abstract
Description
[0001] COMPENSATING FOR FLUID FLOW EFFECTS ON A VISCOSITY METER
[0002] TECHNICAL FIELD
[0003] The embodiments described below relate to viscosity meters and, more particularly, to compensating for fluid flow effects on a viscosity meter.
[0004] BACKGROUND
[0005] Vibratory meters, including densitometers and viscometers, are important tools used to measure a density or a viscosity of a fluid. Vibratory meters may comprise a vibrating element, such as a fork, a cylinder, or a planar resonator, etc. that is exposed to a fluid under test. One example of a vibratory meter comprises a cylinder cantilever mounted with an inlet end coupled to an existing pipeline or other structure and the outlet end free to vibrate. The member can be vibrated at resonance and the resonant response frequency can be measured. The density of the fluid under test can be determined by measuring the reduced response frequency of the vibrating element. According to well-known principles, the resonant frequency of the vibrating element will vary inversely with the density of the fluid that contacts the conduit.
[0006] Viscosity is a fluid characteristic that describes flow resistance. A common definition of viscosity is a measure of the internal friction of a fluid. In particular, this internal friction becomes apparent when a layer of fluid is made to move in relation to another layer. Thus, viscosity is often described as the resistance experienced by one portion of a material moving over another portion of that material. Viscosity is commonly used to characterize petroleum fluids, such as fuels, oils, and lubricants, and often they are specified in the trading and classification of petroleum products. Fork viscosity meters are vibratory meters that use a vibrating tuning fork immersed in a fluid to measure a viscosity of the fluid.
[0007] Fork viscosity meters are influenced by the velocity of the fluid that they are submerged in. The force imparted on the fork by a moving fluid causes deviations in the measured viscosity. Accordingly, there is a need to compensate for fluid flow effects on
[0008]
[0009] SUMMARY
[0010] A method for compensating for fluid flow effects on a viscosity meter is provided. According to an embodiment, the method comprises immersing, in a fluid, a vibratory element of a sensor assembly and detecting a fluid velocity divergence of an electrical property of a transducer coupled to the vibratory element immersed in the fluid. The fluid velocity divergence of the electrical property is due to a fluid velocity of the fluid.
[0011] A viscosity meter configured to compensate for fluid flow effects on the viscosity meter is provided. According to an embodiment, the viscosity meter comprises a sensor assembly having vibratory elements immersed in a fluid and a meter electronics configured to execute a method according to the foregoing.
[0012] A method for compensating for fluid flow effects on a viscosity meter is provided. According to an embodiment, the method comprises immersing, in a fluid, a vibratory element of a sensor assembly and determining a relationship between a fluid velocity divergence of an electrical property of a transducer coupled to the vibratory element and a fluid velocity invariant viscosity of the fluid, wherein the fluid velocity divergence in the electrical property is due to a fluid velocity of the fluid.
[0013] A system for compensating for fluid flow effects on a viscosity meter is provided. According to an embodiment, the system comprises a viscosity meter having a sensor assembly comprising vibratory elements immersed in a fluid, a reference device, and a calibration computer in communication with the viscosity meter and the reference device. The calibration computer is configured to perform the foregoing.
[0014] ASPECTS
[0015] According to an aspect, a method for compensating for fluid flow effects on a viscosity meter comprises immersing, in a fluid, a vibratory element of a sensor assembly and detecting a fluid velocity divergence of an electrical property of a transducer coupled to the vibratory element immersed in the fluid. The fluid velocity divergence of the electrical property is due to a fluid velocity of the fluid.
[0016] Preferably, the fluid velocity divergence is proportional to the fluid velocity of the fluid.Preferably, the fluid velocity divergence of the electrical property is proportional to a divergence in a displacement related parameter of the vibratory element and the divergence in the displacement related parameter of the vibratory element is proportional to the fluid velocity.
[0017] Preferably, the transducer coupled to the vibratory element is a displacement sensor configured to sense the displacement related parameter of the vibratory element immersed in the fluid.
[0018] Preferably, detecting the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element immersed in the fluid comprises determining an electrical property value of the transducer coupled to the vibratory element immersed in the fluid and comparing the electrical property value to at least one threshold value.
[0019] Preferably, the electrical property value comprises at least one of a central tendency value and a dispersion value of the electrical property.
[0020] Preferably, the central tendency value comprises one of a mean, median, and mode of the electrical property and the dispersion value comprises one of a range, variance, and standard deviation of the electrical property.
[0021] Preferably, detecting the fluid velocity divergence of the electrical property comprises determining if at least one of the central tendency value and the dispersion value exceeds a corresponding threshold value.
[0022] Preferably, the electrical property value is an aggregated electrical property value determined from a plurality of samples of the electrical property.
[0023] Preferably, the transducer being coupled to the vibratory element comprises the transducer being affixed to the vibratory element.
[0024] Preferably, the method further comprises determining at least one fluid velocity compensating term based on the fluid velocity divergence of the electrical property and compensating a fluid viscosity variant value using the at least one fluid velocity compensating term.
[0025] Preferably, the at least one fluid velocity compensating term comprises at least one of a fluid velocity compensating coefficient multiplied with the fluid velocity variant viscosity and a fluid velocity variant viscosity intercept.Preferably, compensating the fluid velocity variant viscosity value comprises utilizing the following equation:
[0026]
[0027] " " >
[0028] where:
[0029] hcosR isacorrected viscosity and is a fluid velocity invariant viscosity;
[0030] |imis an uncorrected or measured viscosity and is the fluid velocity variant viscosity; and
[0031] A, B, and C are fluid velocity constants, wherein A and B are fluid velocity compensating coefficients and C is a fluid velocity compensating intercept.
[0032] According to an aspect, a viscosity meter configured to compensate for fluid flow effects on the viscosity meter comprises a sensor assembly having vibratory elements immersed in a fluid and a meter electronics configured to execute a method according to the foregoing.
[0033] Preferably, the viscosity meter further comprises transducers configured to sense a displacement related parameter of the vibratory elements.
[0034] According to an aspect, a method for compensating for fluid flow effects on a viscosity meter comprises immersing, in a fluid, a vibratory element of a sensor assembly and determining a relationship between a fluid velocity divergence of an electrical property of a transducer coupled to the vibratory element and a fluid velocity invariant viscosity of the fluid, wherein the fluid velocity divergence in the electrical property is due to a fluid velocity of the fluid.
[0035] Preferably, determining the relationship between the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element and the fluid velocity invariant viscosity comprises determining a relationship between the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element and a viscosity error of a viscosity value of the fluid and a relationship between the viscosity error of the viscosity of the fluid and the fluid velocity invariant viscosity.
[0036] Preferably, determining the relationship between the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element and the viscosity error of the viscosity value of the fluid comprises determining, at two or morefluid velocities, a plurality of ordered pairs of the fluid velocity divergence in the electrical property and the viscosity error of the viscosity value of the fluid.
[0037] Preferably, the fluid velocity divergence is proportional to the fluid velocity of the fluid.
[0038] Preferably, the fluid velocity divergence of the electrical property value is proportional to a divergence in a displacement related parameter and the divergence in the displacement related parameter of the vibratory element is proportional to the fluid velocity.
[0039] Preferably, the transducer coupled to the vibratory element is a displacement sensor configured to measure the displacement related parameter of the vibratory element immersed in the fluid.
[0040] Preferably, the method further comprises determining the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory clement immersed in the fluid.
[0041] Preferably, determining the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element immersed in the fluid comprises determining the electrical property value of the transducer coupled to the vibratory element immersed in the fluid and comparing the electrical property value to a reference value of the electrical property.
[0042] Preferably, the electrical property value comprises at least one of a central tendency value and a dispersion value of the electrical property.
[0043] Preferably, the central tendency value comprises one of a mean, median, and mode and the dispersion value comprises one of a range, variance, and standard deviation.
[0044] Preferably, the electrical property value is an aggregated electrical property value determined from a plurality of samples of the electrical property.
[0045] Preferably, the transducer being coupled to the vibratory element comprises the transducer being affixed to the vibratory element.
[0046] Preferably, the method further comprises determining at least one fluid velocity compensating term based on the fluid velocity divergence in the electrical property for compensating a fluid velocity variant viscosity value with the at least one fluid velocity compensating term.Preferably, the at least one fluid velocity compensating term comprises a fluid velocity compensating coefficient for the fluid velocity variant viscosity and / or a fluid velocity compensating constant.
[0047] Preferably, determining the relationship between the divergence of the electrical property of the transducer coupled to the vibratory element and the fluid velocity invariant viscosity of the fluid comprises determining a functional relationship between the fluid velocity invariant viscosity and a fluid velocity variant viscosity of the fluid.
[0048] Preferably, the functional relationship between the fluid velocity invariant viscosity value and the fluid velocity variant viscosity value comprises determining a fluid velocity compensating intercept.
[0049] Preferably, the functional relationship comprises the following equation:
[0050]
[0051] where:
[0052] PCORR isacorrected viscosity and is the fluid velocity invariant viscosity; pmis an uncorrected or measured viscosity and is the fluid velocity variant viscosity; and
[0053] A, B, and C are fluid velocity constants, wherein A and B are fluid velocity compensating coefficients and C is a fluid velocity compensating intercept.
[0054] According to an aspect, a system for compensating for fluid flow effects on a viscosity meter comprises a viscosity meter having a sensor assembly comprising vibratory elements immersed in a fluid, a reference device, and a calibration computer in communication with the viscosity meter and the reference device. The calibration computer is configured to perform the foregoing.
[0055] BRIEF DESCRIPTION OF THE DRAWINGS
[0056] The same reference number represents the same element on all drawings. It should be understood that the drawings are not necessarily to scale.
[0057] FIG. 1 shows a viscosity meter 5 configured to compensate for fluid flow effects on the viscosity meter 5.
[0058] FIG. 2 shows the viscosity meter 5 configured to compensate for fluid flow effects on the viscosity meter 5.FIG. 3 shows a graph 300 for compensating for fluid flow effects on a viscosity meter.
[0059] FIG. 4 shows the meter electronics 20 configured to compensate for fluid flow effects on a viscosity meter.
[0060] FIGS. 5A-5D show a viscosity meter 505 that may not compensate for fluid flow effects.
[0061] FIG. 6 shows a graph 600 relating a fluid velocity to viscosity error for compensating for fluid flow effects on a viscosity meter.
[0062] FIG. 7 shows a graph 700 for compensating for a fluid flow effect on a viscosity meter.
[0063] FIG. 8 shows a graph 800 for compensating for fluid flow effects on a viscosity meter.
[0064] FIG. 9 shows a method 900 of compensating for fluid flow effects on a viscosity meter.
[0065] FIG. 10 shows a method 1000 of compensating for fluid flow effects on a viscosity meter.
[0066] FIG. 11 shows a calibration system 1100 for compensating for fluid flow effects on a viscosity meter.
[0067] FIG. 12 shows a method 1200 of calibration for compensating for fluid flow effects on a viscosity meter.
[0068] DETAILED DESCRIPTION FIGS. 1-12 and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of embodiments of compensating for fluid flow effects on a viscosity meter. 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 description. Those skilled in the art will appreciate that the features described below can be combined in various ways to compensate for fluid flow effects on a viscosity meter. As a result, the embodiments described below are not limited to the specific examples described below, but only by the claims and their equivalents.FIG. 1 shows a viscosity meter 5 configured to compensate for fluid flow effects on the viscosity meter 5. As shown in FIG. 1, the viscosity meter 5 is comprised of a sensor assembly 10 and a meter electronics 20 that is communicatively coupled to the sensor assembly 10. The sensor assembly 10 is a fork viscosity meter. Hie sensor assembly 10 may contain, immerse into, be exposed to, and / or the like, a fluid to be measured. The sensor assembly 10 provides information on the sense property to the meter electronics 20. The information may be provided by electrical signals, optical signals, or the like. The information may be provided by any suitable means, such as, for example, modulating a property (e.g., voltage, current, power, etc.) of an electrical signal. The modulation may be digital, analog, mixed signal, etc.
[0069] The meter electronics 20 can use the information to convert the information into a measurement. This conversion typically utilizes one or more calibration factors that may offset and / or scale the information into the measurement. The fluid measurement may be comprised of one or more fluid measurement values. Accordingly, the meter electronics 20 can provide the fluid measurement via a port 26, such as a communications terminal, interface, or the like. As will be explained in more detail in the following, the measurement of the fluid can be affected if characteristics of the sensor assembly 10 changes relative to a baseline or reference calibration.
[0070] The sensor assembly 10 may be configured to sense a property of the fluid. With more specificity, vibratory elements 130 may be configured to be immersed in the fluid to measure the properties of the fluid. It should be appreciated that the vibratory elements 130 being immersed in the fluid may be a partial and / or complete immersion, an exposure to the fluid, and / or the like that is sufficient to measure a viscosity of the fluid. The vibratory elements 130 can be configured to vibrate at various frequencies by transducers 120. The vibratory elements 130 can sense the fluid parameters with one or more displacement related parameters of the vibratory element. The displacement related parameter can include an amplitude, frequency, phase, and / or the like of the vibration.
[0071] The vibratory elements 130 may include conduits that contain the fluid, such as conduits in a Coriolis meter, tines on a fork meter that is immersed in the fluid, or the like, as is explained in more detail in the following. The properties of the fluid, or the fluid properties, may include a flow rate, such as a mass or volume flow rate, density,viscosity, or the like. The properties of the fluid may also include a temperature, pressure, and / or the like, of the fluid.
[0072] The sensor assembly 10 may also be configured to sense non- fluid properties, such as temperature, containment pressure of a housing, and / or vibration frequency of one or more vibratory elements. The sensor assembly 10 may provide information related to the properties of the fluid via the communication channels 100. The sensor assembly 10 may also receive information via the communication channels 100, such as a drive signal, from the meter electronics 20.
[0073] Additionally, or alternatively, although not shown in FIG. 1 , a transducer, such as a temperature and / or pressure transducer, may be mechanically coupled to a container, pipeline, or the like, that is / are coupled with the sensor assembly 10 to sense the fluid that is provided to the sensor assembly 10. Such transducers, which may be referred to as external transducers, may be communicatively coupled to the meter electronics 20 in addition to the sensor assembly 10. The external transducers may provide such information to the meter electronics 20 via, for example, the port 26 shown in FIG. 1 , although additional ports or the like may be employed.
[0074] Fork meter
[0075] FIG. 2 shows a block diagram of the viscosity meter 5 configured to compensate for fluid flow effects on the viscosity meter 5. As shown in FIG. 2, the viscosity meter 5 includes the meter electronics 20 that is communicatively coupled to the sensor assembly 10 as described with reference to FIG. 1. The meter electronics 20 is also mechanically coupled to a sensor assembly 10 by a shaft 115. The shaft 115 may be of any desired length. The shaft 115 may be at least partially hollow. Wires or other conductors may extend between the meter electronics 20 and the vibratory element 130 through the shaft 115. The meter electronics 20 includes circuit components such as a receiver circuit 134, an interface circuit 136, and a driver circuit 138. In the embodiment shown, the receiver circuit 134 and the driver circuit 138 are directly coupled to the leads of the vibratory elements 130. Alternatively, the meter electronics 20 can comprise a separate component or device from the vibratory element 130, wherein the receiver circuit 134 and the driver circuit 138 are coupled to the vibratory elements 130 via communication channels.In the embodiment shown, the vibratory element 130 of the viscosity meter 5 comprises a tuning fork structure, wherein the vibratory elements 130 are at least partially immersed in the process fluid being measured. The vibratory elements 130 include a housing 105 that can be affixed to another structure, such as a pipe, conduit, tank, receptacle, manifold, or any other fluid-handling structure. The housing 105 retains the vibratory elements 130 while the vibratory element 130 remains at least partially exposed to the process fluid. The vibratory element 130 is therefore configured to be immersed in the fluid.
[0076] The vibratory elements 130 in the embodiment shown includes a first and second vibratory element 130d and 130s that are configured to extend at least partially into the fluid. The first and second vibratory elements 130d and 130s comprise elongated elements, which may be referred to as tines, that may have any desired cross-sectional shape. The first and second vibratory elements 130d and 130s may be at least partially flexible or resilient in nature. The viscosity meter 5 further includes the transducers 120 which, as shown in FIG. 2, comprises corresponding first and second piezo elements 122 and 124 that comprise piezo-electric crystal transducers (PCTs). The first and second piezo elements 122 and 124 are located adjacent to the first and second vibratory elements 130d and 130s, respectively. The first and second piezo elements 122 and 124 are configured to contact and mechanically interact with the first and second vibratory elements 130d and 130s.
[0077] The first piezo element 122 is in contact with at least a portion of the first vibratory element 130d. The first piezo element 122 is also electrically coupled to the driver circuit 138. The driver circuit 138 provides the generated drive signal to the first piezo element 122. The first piezo element 122 expands and contracts when subjected to the generated drive signal. As a result, the first piezo element 122 may alternatingly deform and displace the first vibratory element 130d from side to side in a vibratory motion (see dashed lines), disturbing the fluid in a periodic, reciprocating manner.
[0078] The second piezo element 124 is shown as coupled to a receiver circuit 134 that produces the vibration signal corresponding to the deformations of the second vibratory element 130s in the fluid. Movement of the second vibratory element 130s causes a corresponding electrical vibration signal to be generated by the second piezo element 124. The second piezo element 124 transmits the vibration signal to the meterelectronics 20. The meter electronics 20 includes the interface circuit 136. The interface circuit 136 can be configured to communicate with external devices. The interface circuit 136 communicates a vibration measurement signal or signals and may communicate determined fluid characteristics to one or more external devices. The meter electronics 20 can transmit vibration signal characteristics via the interface circuit 136, such as a vibration signal frequency and a vibration signal amplitude of the vibration signal. The meter electronics 20 may transmit fluid measurements via the interface circuit 136, such as a density and / or viscosity of the fluid, among other things. Other fluid measurements are contemplated and are within the scope of the description and claims. In addition, the interface circuit 136 may receive communications from external devices, including commands and data for generating measurement values, for example. In some embodiments, the receiver circuit 134 is coupled to the driver circuit 138, with the receiver circuit 134 providing the vibration signal to the driver circuit 138. The driver circuit 138 generates the drive signal for the vibratory element 130. The driver circuit 138 can modify characteristics of the generated drive signal. The vibratory element 130 is generally maintained at a resonant frequency, as influenced by the surrounding fluid.
[0079] The viscosity meter 5 comprising the fork meter can measure properties of a fluid, such as density, viscosity, etc. The density, similar to a density determined using the first and second vibratory elements 130d, 130s discussed above, can be determined from a period of the vibratory element 130, as is expressed in the following equation [1]:
[0080] P fluid = C T2+ C2Equation [1] where:
[0081] P fluid is the fluid density;
[0082] are constants; and
[0083] T is the period of fork oscillation.
[0084] As can be seen, the fluid density Pfiut . is determined based on the period of the fork and two constants C1;C2. The two constants scale and offset the information received from the vibratory element 130 to obtain the density.
[0085] Viscosity may be determined by balancing the Navier-Stokes equation and Newton’s Laws of Motion, yielding an equation of the form:
[0086]
[0087] where:
[0088] p is the fluid viscosity;
[0089] p is the fluid density;
[0090] a>0is the angular resonant frequency undamped (27tfo);
[0091] A is a constant relating to the Q of the resonator in vacuum;
[0092] B is a constant relating to the stiffness, mass and geometry of the sensor; and Q is a dimensionless parameter that describes how underdamped an oscillator or resonator is.
[0093] The density and resonant frequency are related by an equation of the form:
[0094] Equation [3]
[0095]
[0096] Where:
[0097] C and D are constants relating to the stiffness, mass and geometry of the resonator. Combining and performing substitution, the above equations [2] and [3] results in:
[0098] Equation [4]
[0099]
[0100] For simplicity, the resonant frequency can be regarded as the same as f0, which is the undamped resonant frequency. For many practical applications a viscosity sensor would be calibrated on similar fluids to those measured in the field, and hence the frequency would be unchanged, so the frequency can be regarded as a constant, and hence the equation can take a form similar to the following:
[0101] p = A + — ; Equation [5]
[0102] where:
[0103] E is a constant based on the stiffness, mass and geometry of the sensor and resonant frequency.
[0104] The equations provided arc provided as non-limiting examples.
[0105] A fork viscosity meter (FVM), such as the viscosity meter 5 described with reference to FIGS. 1 and 2, is based upon a principle that resonant properties are influenced by the density and viscosity of the fluid. A fork viscosity utilizes this principle to determine liquid viscosity. In particular, viscosity is determined by measuring the quality factor Q of the resonance and hence damping of the resonator. Forexample, without limitation, the following Equation [6] can be used to describe one possible method for determining viscosity:
[0106] Equation [6]
[0107]
[0108] where:
[0109] 70and Vsare calibration constants.
[0110] Q may be measured as resonance frequency divided by bandwidth as shown:
[0111] < Equation [7]
[0112]
[0113] where:
[0114]
[0115] are 3dB frequency points.
[0116] The 3dB frequency points are discussed in more detail in the following.
[0117] FIG. 3 shows a graph 300 for compensating for fluid flow effects on a viscosity meter. As shown in FIG. 3, the graph 300 relates amplitude to a frequency of a sensor assembly, such as the sensor assembly 10 described above. The graph 300 is comprised of a frequency axis 310 and an amplitude axis 320 respectively ranging from 1000 to 3000 Hertz (Hz) and amplitude units, although any suitable parameters, such as timeperiods and voltages, for example, may be employed. The graph 300 includes an amplitude-frequency plot 330 that increases from a little less than 0.3 at 1000 Hz to 1.0 at about 1990 Hz and then down to about 0.18 at 3000 Hz, although any suitable amplitude frequency plot may be employed. Shown on the amplitude-frequency plot are 3dB points / 7, / 2 below and above the resonant frequency fO.
[0118] As discussed above, a viscosity value can be determined based on the quality factor Q. Also as discussed above, a viscosity value can be affected by fluid flow effects. The following describes how to compensate for the fluid flow effects on a viscosity meter.
[0119] Meter electronics
[0120] FIG. 4 shows the meter electronics 20 configured to compensate for fluid flow effects on a viscosity meter. As shown in FIG. 4, the meter electronics 20 includes an interface 401 and a processing system 402. The meter electronics 20 receives a vibrational response from a sensor assembly, such as the sensor assembly 10 described above, for example. The meter electronics 20 can process the vibrational response toobtain flow properties of the flow material flowing through the sensor assembly 10. The meter electronics 20 may also perform checks, verifications, calibration routines, and / or the like, to ensure the flow properties of the flow material are accurately measured.
[0121] With respect to the viscosity meter 5 shown in FIG. 2, the interface 401 may provide a drive signal to the first piezo element 122 and receive a sensor signal from the second piezo element 124. As discussed above, a fluid velocity can affect the sensor signal provided by the second piezo element 124. More specifically, the fluid flow presses against the first and / or second vibratory elements 130d, 130s.
[0122] The interface 401 can perform any necessary or desired signal conditioning, such as any manner of formatting, amplification, buffering, etc. Alternatively, some or all of the signal conditioning can be performed in the processing system 402. In addition, the interface 401 can enable communications between the meter electronics 20 and external devices. The interface 401 can be capable of any manner of electronic, optical, or wireless communication. The interface 401 can provide information based on the vibrational response. The interface 401 may be coupled with a digitizer, wherein the sensor signal comprises an analog sensor signal. The digitizer samples and digitizes an analog sensor signal and produces a digitized sensor signal.
[0123] The processing system 402 conducts operations of the meter electronics 20 and processes fluid measurements from the sensor assembly 10. The processing system 402 executes one or more processing routines and thereby processes the fluid measurements in order to produce one or more fluid properties. The processing system 402 is communicatively coupled to the interface 401 and is configured to receive the information from the interface 401.
[0124] The processing system 402 can comprise a general-purpose computer, a microprocessing system, a logic circuit, or some other general purpose or customized processing device. Additionally, or alternatively, the processing system 402 can be distributed among multiple processing devices. The processing system 402 can also include any manner of integral or independent electronic storage medium, such as the storage system 404.
[0125] The storage system 404 can store vibratory meter parameters and data, software routines, constant values, and variable values. In one embodiment, the storage system 404 includes routines that are executed by the processing system 402, such as anoperational routine 410. The processing system 402 may further be configured to execute other routines such as a zero-calibration routine and zero-verification routine of the viscosity meter 5. The storage system 404 can also store statistical values, such as a mean, standard deviation, confidence interval, etc., or the like.
[0126] The operational routine 410 may determine a density 412 and a viscosity 414 based on the sensor signals received by the interface 401. Similarly, a calibration routine 420, such as described with reference to FIG. 12 below, may be employed. For example, the calibration routine 420 may determine electrical properties 422, such as a voltage of the sensor signals as well as fluid velocities 424 provided by, for example, another device. The interface 401 may be in communication with and receive the fluid velocities 424 from the device during, for example, calibration.
[0127] Also shown is a compensating routine 430 that can determine a corrected viscosity value, which may be stored as the viscosity 414 value. The corrected viscosity value may be referred to as a fluid velocity invariant viscosity value. That is, the viscosity value does not vary substantially according to a fluid flow rate. The corrected viscosity value may be determined using a compensating relationship 432 that employs compensating constants 434 that were determined using, for example, the calibration routine 420. The compensating relationship 432 may be in analytical, data array, etc. form, although any suitable form may be employed.
[0128] Recess cavity
[0129] FIGS. 5A-5D show a viscosity meter 505 that may not compensate for fluid flow effects. As shown in FIGS. 5A through 5D, the viscosity meter 505 are variations of a viscosity meter where a sensor assembly 10 is positioned at different depths in a first through fourth recess 503A-503D extending from a pipeline 501 conveying a fluid flow. The different depths are determined by a length of the first through fourth recess 503A-503D. The depths are shown as being zero in FIG. 5A, one inch in FIG. 5B, 1.5 inches in FIG. 5C, and two inches in FIG. 5D, although any suitable depths can be employed. The depths are specified for a given viscosity and fluid velocity range. As can be appreciated, modifying the pipeline 501 to include one of the specified first through fourth recess 503A-503D represents an additional cost for a purchaser of the viscosity meter 505. As can also be appreciated, a viscosity value provided by the viscosity meter505 is only reliable if the measured fluid is within the specified viscosity and fluid velocity ranges.
[0130] Accordingly, by compensating for fluid flow effects, a significant improvement to a process is realized. In addition, compensating for the fluid flow effect rather than using the recesses described with reference to FIGS. 5A-5D can increase measurement sensitivity without sacrificing overall accuracy. The following describes exemplary compensations for fluid flow effects on a viscosity value.
[0131] Fluid flow effects
[0132] The fluid flow effects on a vibratory element of a viscosity meter can be due to compression of one side of the fork in a fluid flow stream. In static no flow conditions, during vibration, a potential energy of a deflected vibratory element or tine converts back into kinetic energy of the vibratory element tine. However, in the presence of a fluid flow some of the kinetic energy is lost due to the opposing kinetic energy of the fluid flow. This lost energy increases system damping and increases a quality factor Q of the viscosity meter, which in turn expectedly increases the viscosity measurement.
[0133] As can be appreciated, the fluid velocity or compression can cause a divergence in an electrical property of a transducer. For example, a piezoelectric voltage may increase due to the fluid flow causing a divergence in a displacement related parameter of a vibratory element measured by a piezoelectric transducer. Accordingly, a divergence of an electrical property can be a bias in an electrical property value.
[0134] Additionally, or alternatively, the divergence in the electrical property may include an increased (in proportion to the fluid velocity) variability about a central value of the electrical property. The fluid flow effect on the electrical property of the transducer can be referred to as a fluid velocity divergence. Accordingly, the fluid velocity divergence can be observed as a bias and / or a variance, as a function of fluid velocity, of an electrical property value.
[0135] FIG. 6 shows a graph 600 relating a fluid velocity to viscosity error for compensating for fluid flow effects on a viscosity meter. As shown in FIG. 6, the graph 600 is comprised of a fluid velocity axis 610, a fork viscosity error 620, and voltage error axis 630 respectively ranging from zero to 12 feet-per- second (ft / s), zero to 60 cP, and 0.55 to 0.80 volts (V), although any suitable range and parameters may be employed. Also shown are left pickoff voltage data points 640 shown as square markers,viscosity error data points 650 shown as circular markers, and voltage limits 660 indicated as dashed lines. As can be appreciated, the left pickoff voltage data points 640 and viscosity error data points 650 respectively relate left pickoff voltage and viscosity error to fluid velocity values. The voltage limits 660 may be set to indicate when a fluid velocity can cause a significant viscosity error. As shown in FIG. 6, the voltage limits 660 are at about 0.66 and 0.65 volts.
[0136] As can be appreciated, the left pickoff voltage data points 640 is at about 0.65 V and within the voltage limits 660 over a range of fluid velocity values of zero to 2 feet-per-second. At a fluid velocity of about 3 feet-per-second, some of the left pickoff voltage data points 640 exceeds an upper limit of the voltage limits 660. At this fluid velocity, the left pickoff voltage data points 640 are at about 0.66 V with a spread of about ±0.10 V. At a fluid velocity value of about 6 feet-per-second, the left pickoff voltage data points 640 arc at about 0.69 V with a spread of about ±0.15 V. At a fluid velocity value of 10 feet-per-second, the left pickoff voltage data points 640 is at about 0.72 with a spread of about ±0.20. As can be appreciated, the left pickoff voltage data points 640 suggests a somewhat linear correlation between the values of the left pickoff voltage data points 640 and fluid velocity. It can also be appreciated that a spread or variance of the left pickoff voltage data points 640 also increases in proportion to the fluid velocity.
[0137] FIG. 6 demonstrates that flow testing established a relationship between a piezoelectric voltage and viscosity error in viscosity meters. At fluid velocities below 3 ft / sec the viscosity error and the piezoelectric voltage remain stable. At and above 3 ft / sec there is a change or divergence in average piezoelectric voltage and the standard deviation of piezoelectric voltage. Accordingly, a fluid velocity divergence in an electrical property can be used to detect a fluid flow effect on the viscosity meter. The fluid velocity divergence can be a value that is different than a reference central tendency value and / or dispersion value of the electrical property. For example, a reference mean value of the electrical property can be determined when there is no fluid flow. Additionally, or alternatively, a reference standard deviation value of the electrical property can be determined when there is no fluid flow. During operation, samples of the electrical property can be obtained, and a mean and / or standard deviation of thesamples can be compared to their respective threshold values. The reference and / or threshold values can be determined during calibration.
[0138] An air calibration could be conducted, for example immediately, after the fork is assembled. The electrical property values, such as voltages, can be recorded during the calibration. Afterwards, the average value can be stored in a meter electronics, such as the meter electronics 20 described above, although any suitable meter electronics may be employed. It should be noted that entrained air “void fraction” can also cause the standard deviation of the pickoff voltage to increase. If the entrained air effect on the electrical property is sufficient, then a fluid flow effect may incorrectly be indicated. However, the potential induced error could be very small compared to the fluid flow effect. Accordingly, the standard deviation can predict fluid velocity induced viscosity errors. The standard deviation can also have the added benefit of not needing an air calibration point.
[0139] As the foregoing discussion of FIG. 6 shows, the divergences in the electrical property value correspond with a significant increase in viscosity error, as illustrated by the viscosity error data points 650. The relationship between these two variables allows for the error to be reliably detected and compensated for without need for any form of human intervention.
[0140] Viscosity effect on viscosity error
[0141] The fluid flow effect on viscosity measurement may have a relative viscosity component as well. That is, the magnitude of the viscosity error may be different depending on the viscosity of the fluid, which can affect whether the viscosity errorfluid flow rate relationship has a polynomial, linear, constant, or the like, relationship.
[0142] FIG. 7 shows a graph 700 for compensating for a fluid flow effect on a viscosity meter. As shown in FIG. 7, the graph 700 relates viscosity and viscosity error. The graph 700 includes a viscosity axis 710 and a viscosity error axis 720 respectively ranging from zero to 600 centipoise (cP) and zero to 70 cP, although any suitable ranges and / or units may be employed. Also shown is a viscosity error-viscosity curve 730 that increases from zero to 60 cP over a range of 0 to 500 cP. Also shown are data points indicated as circular markers superimposed on the viscosity error-viscosity curve 730. The data points are comprised of a test data point indicated by a solid disk and estimated data points indicated as empty circles. The graph 700 illustrates exemplary error valuesthat may be obtained from a viscosity meter, such as the viscosity meter 5 described above, when the fluid velocity is at 3 feet-per- second (ft / s). Also shown is an alternative fluid velocity viscosity error-viscosity curve 740 which could be obtained at higher fluid velocities (e.g., 4 ft / s, 5 ft / s, etc.).
[0143] It should be appreciated that the alternative fluid velocity viscosity errorviscosity curve 740 and the estimated data points are inferred from fluid dynamics. More specifically, ignoring possible complex fluid dynamics around the vibratory elements or tines of a sensor assembly, such as the vibratory elements 130 described above, an increase in shear stress across the vibratory elements or tines will increase system damping and thus increase a viscosity bias. It is believed that shear stress from the fluid moving around tines, such as the vibratory elements 130 described above, is a dominant or sole force behind the viscosity bias. In Newtonian fluids, the relationship between shear stress and shear rate is linear so it is expected that the viscosity bias would be linear as well. That is, an increase in shear rate is proportional to an increase in the viscosity bias.
[0144] Accordingly, for example, regardless of whether the relationship is polynomial, linear, or constant, it can be corrected for using the following Equation [8] as a general expression or starting point:
[0145] hcorr=21p.m + B im+ C Equation [8]
[0146] where:
[0147] p.corris a corrected viscosity and can be referred to as a fluid velocity invariant viscosity;
[0148] p.mis an uncorrcctcd or measured viscosity and may be referred to as a fluid velocity variant viscosity; and
[0149] A, B, and C are constants determined through testing and may be referred to fluid velocity compensating constants, wherein A and B are fluid velocity compensating coefficients and C is a fluid velocity compensating
[0150]
[0151] Equation [8] and the constants A, B, and C may respectively be stored in the meter electronics 20 as the compensating relationship 432 and the compensating constants 434, although any suitable storage means and / or labels may be employed.
[0152] It should be appreciated that the difference between the viscosity error- viscosity curve 730 and the alternative fluid velocity viscosity error-viscosity curve 740 is the fluid velocity compensating intercept C. The compensating intercept C may increase linearly with respect to velocity. Additionally, or alternatively, other fluid velocity viscosity error-viscosity curves may have different constants A, B, and C, depending on fluid velocity. For example, simulations may show that the fluid velocity compensating coefficients A and / or B may vary depending on fluid velocity, or other effects.
[0153] Additionally, or alternatively, although the above example relationship is polynomial, other relationships can be employed such as non-polynomial, linear, and / or constants, other non-polynomial, and / or the like can be employed. It should also be appreciated that the above expression is an analytical form that can be obtained via regression. Alternative compensation relationships can employ, for example, empirical data where values are obtained via interpolation and / or extrapolation. That is, any suitable method, form, etc., for compensating a fluid velocity variant viscosity value for fluid velocity may be employed.
[0154] The above Equation [8] is a relationship between a fluid velocity variant viscosity and a fluid velocity invariant viscosity. That is, Equation [8] does not use viscosity error values determined during calibration to correct a fluid velocity variant viscosity value. However, any suitable relationship can be used to correct an uncorrected viscosity value. For example, it may be desirable to use electrical property values, calibration viscosity error values, reference viscosity values, and / or the like to determine a corrected viscosity icorrvalue from an unconnected viscosity
[0155]
[0156] value during operation.
[0157] Accordingly, once the viscosity error is detected using the divergence in the pickoff voltage described with reference to FIG. 6, Equation [8] can then be used to drive the enor to zero regardless of the fluid's viscosity, as described in the following.
[0158] Uncorrected and corrected viscosity errors
[0159] FIG. 8 shows a graph 800 for compensating for fluid flow effects on a viscosity meter. As shown in FIG. 8, the graph 800 relates uncorrected and corrected viscosityerror values to fluid velocity. The graph 800 includes a fluid velocity axis 810 and a viscosity error axis 820 that respectively range from zero to 12 feet-per- second (ft / s) and minus 5 to 20 cP, although any suitable range and units may be employed. Also shown are viscosity error data points 830 and corrected viscosity error data points 840. The viscosity error data points 830 show viscosity error values at various fluid velocity values. The corrected viscosity error data points 840 illustrate a result of compensating a flow velocity variant viscosity value as described above with reference to Equation [8].
[0160] Accordingly, the corrected viscosity error data points 840 shown in FIG. 8 can be determined by inputting the uncorrected or fluid velocity variant viscosity value into the compensating relationship, such as one based on the above-described Equation [8], to determine a corrected or fluid velocity invariant viscosity value. More specifically, the constants A, B, C in Equation [8] may correspond to one or more viscosity errors and / or a divergence in the electrical property of a transducer.
[0161] Referring still to Equation [8], it should be appreciated that the fluid velocity divergence in the electrical property, and thus the viscosity error, is detected, but a value of the detected viscosity error during a customer process is not subtracted from the uncorrected viscosity value. Instead, the compensating relationship and compensating constants are determined during a calibration, which is described in more detail in the following with reference to FIG. 12. During operation, such as during a customer process, the fluid velocity variant viscosity, such as an uncorrected measured viscosity value, can be corrected using the constants and Equation [8], as the following description explains.
[0162] Method
[0163] FIG. 9 shows a method 900 of compensating for fluid flow effects on a viscosity meter. The method 900 may be executed by the meter electronics 20 discussed above, although any suitable meter electronics may be employed. As shown in FIG. 9, the method 900 immerses, in a fluid, a vibratory element of a sensor assembly in step 910. In step 920, the method 900 detects a fluid velocity divergence of an electrical property of a transducer coupled to the vibratory element immersed in the fluid. The sensor assembly of the method 900 may be, for example, the sensor assembly 10 described above, although any suitable sensor assembly may be employed.The transducer coupled to the vibratory element can be a displacement sensor configured to sense the displacement related parameter of the vibratory element immersed in the fluid. For example, the transducer and vibratory element of the method 900 may respectively be the transducers 120 and vibratory elements 130 described with reference to FIG. 1 , although any suitable transducers and / or vibratory elements may be employed. Additionally, or alternatively, the transducer being coupled to the vibratory element may comprise the transducer being affixed to the vibratory element.
[0164] The fluid velocity divergence of the electrical property may be due to a fluid velocity of the fluid. Accordingly, the fluid velocity divergence may be proportional to the fluid velocity of the fluid. For example, the fluid velocity divergence of the electrical property can be proportional to a divergence in a displacement related parameter of the vibratory element and the divergence in the displacement related parameter of the vibratory clement can be proportional to the fluid velocity.
[0165] Detecting the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element immersed in the fluid can comprise determining an electrical property value of the transducer coupled to the vibratory element immersed in the fluid and comparing the electrical property value to at least one threshold value. The threshold values can be an upper limit and / or a lower limit on the electrical property value. If the electrical property is greater than the upper limit and / or is less than the lower limit, then a divergence may be detected.
[0166] It should be appreciated that the electrical property value can comprise at least one of a central tendency value and a dispersion value of the electrical property. For example, the electrical property value may have one or two terms comprising a central tendency value and / or a dispersion value. The central tendency value can comprise at least one of a mean, median, and mode of the electrical property and the dispersion value can comprise one of a range, variance, and standard deviation of the electrical property. Accordingly, detecting the fluid velocity divergence of the electrical property can comprise determining if at least one of the central tendency value and the dispersion value exceeds a corresponding threshold value. The electrical property value may be an aggregated electrical property value determined from a plurality of samples of the electrical property.The method 900 may further comprise determining at least one fluid velocity compensating term based on the fluid velocity divergence of the electrical property and compensating a fluid velocity variant viscosity value using the at least one fluid velocity compensating term. The at least one fluid velocity correction term can comprise at least one of a fluid velocity compensating coefficient multiplied with the fluid velocity variant viscosity and the fluid velocity variant viscosity intercept. Compensating the fluid velocity variant viscosity value may comprise utilizing the above-described Equation [8] where the terms dq?2;i. Bpm, and C are exemplary fluid velocity correction terms.
[0167] As can be appreciated from the foregoing discussion, the electrical property value of a transducer can be, for example, a mean and / or a standard deviation.
[0168] Accordingly, the mean and standard deviation can be compared with their respective threshold values, alone or together, with various logical relationships. In one example, the standard deviation can be compared to upper and lower standard deviation limits to detect a deviation in the electrical property. The following describes an example, where both a mean and a standard deviation is used to detect the deviation in the electrical property of the transducer.
[0169] FIG. 10 shows a method 1000 of compensating for fluid flow effects on a viscosity meter. The method 1000 determines a reference piezo voltage average value Epz^G-REFand a reference piezo voltage standard deviation VpzSTDEV- REFin step 1010. In step 1020, the method 1000 determines a process piezo voltage average value PZAVG-PRC- The method 1000, in step 1030, compares the process piezo voltage average value VpzAVG -PRCand an upper reference piezo voltage average value ^UL^PZAVG-REF andalower reference piezo voltage average value FLLVpzAVG -REP, where FULand FLLare respectively upper and lower control limit factors, such as, for example, 1.2 and 0.8. If true, then the method 1000 proceeds to step 1050 which is an indication of “no change.” If not true, then the method 1000 proceeds to step 1040. In step 1040, the method 1000 determines and compares the process piezo voltage standard deviation value VpzSTDEV-PRCto an upper reference piezo voltage standard deviation FsTDEV-ui PzSTDEV-REF- If true, then a deviation in an electrical property is detected, a compensation is applied, and a notification is sent in step 1060. Otherwise, the method 1000 proceeds to the step 1050.As can be appreciated, the above methods 900, 1000 rely on reference and threshold values. As noted above, the reference and threshold values can be determined during a calibration, such as, for example, the calibration discussed below.
[0170] Calibration
[0171] FIG. 11 shows a calibration system 1100 for compensating for fluid flow effects on a viscosity meter. As shown in FIG. 11, the calibration system 1100 comprises a viscosity meter 1105 that is communicatively coupled with a calibration computer 1130. The calibration computer 1130 is communicatively coupled with a reference flow rate device 1140. The vibratory meter is shown as being comprised of a sensor assembly 1110 that is communicatively coupled with a meter electronics 1120. The calibration computer 1130 is communicatively coupled with the meter electronics 1120. The viscosity meter 1105 and the reference flow rate device 1140 are affixed to a pipeline and may be configured to measure a parameter, such as a fluid velocity, of a fluid flow indicated by arrows. Also shown are transducers 1112 affixed to vibratory elements 1113 and communicatively coupled with the meter electronics 1120.
[0172] The viscosity meter 1105 may be any suitable vibratory meter, such as, for example, the viscosity meter 5 described with reference to FIGS. 1 and 2. The calibration computer 1130 may be any suitable circuit, algorithm, device, computing elements, and / or the like capable of performing a calibration on the viscosity meter 1105. The reference flow rate device 1140 may be any suitable device configured to provide fluid velocity invariant viscosity and / or fluid velocity value(s), such as a reference viscosity pR£F, to the calibration computer 1130. The reference flow rate device 1140 may be a flow measurement device, a user input screen, a memory, and / or the like. It should be appreciated that a fluid velocity value may not be needed to calibrate the viscosity meter 1105.
[0173] Accordingly, it should be appreciated that the calibration computer 1130 may be separate from and / or integrated with the viscosity meter 1105 and may, for example, be an algorithm executed on the meter electronics 1120. Similarly, an alternative reference flow rate device may be something other than a fluid measurement device but may be, for example, a memory in the viscosity meter 1105, such as a memory in the meter electronics 1120. The calibration computer 1130, reference flow rate device 1140, and / or other hardware, may be referred to as a calibration stand.As explained above, a fluid velocity variant viscosity value determined by the viscosity meter 1105 is dependent on a fluid velocity divergence in an electrical property of the transducers 1112 configured to measure a displacement related parameter of the sensor assembly 1110 immersed in the fluid. The displacement related parameter can be affected by and correlated with the fluid velocity. As discussed above, the displacement related parameter may be stress, strain, bend, etc., of, for example, a vibratory element 1113 of the sensor assembly 1110 immersed in the fluid.
[0174] Accordingly, a divergence in the electrical property, such as, for example, a piezoelectric voltage of a piezo element of the transducers 1112 in the sensor assembly 1110 can be dependent on a fluid velocity. As can be appreciated, the electrical property may have a zero fluid velocity value that can serve as a reference electrical property value to determine a fluid velocity divergence in the electrical property. That is, the electrical property can diverge from a reference value of the electrical property. As the foregoing discussion with reference to, for example, FIG. 10, the fluid velocity divergence can be a mean and / or a variance of the electrical property. The fluid velocity divergence in the electrical property can therefore be correlated with a viscosity error and thus with a relationship between a fluid velocity variant viscosity value and a fluid velocity invariant viscosity value.
[0175] More specifically, as can be appreciated, the reference viscosity ^REFmay be known and may be assumed to remain constant at various fluid velocities. Accordingly, a correlation may be made between a divergence in an electrical property of a transducer 1112 and fluid velocity variant viscosity or, with more particularity, a viscosity error. That is, a difference between the reference viscosity HREF °f the fluid measured by the viscosity meter 1105 and the fluid velocity variant viscosity value determined (e.g., the measured viscosity Hmeasshown in FIG. 11) by the viscosity meter 1105 can be calculated and correlated with a divergence in an electrical property of the transducers 1112. Subsequently, during operation, the fluid velocity divergence in the electrical property can be detected and a corresponding viscosity error can be used to correct a measured viscosity value, as is described above.
[0176] FIG. 12 shows a method 1200 of calibration for compensating for fluid flow effects on a viscosity meter. As shown in FIG. 12, the method 1200 immerses, in a fluid, a vibratory element of a sensor assembly in step 1210. In step 1220, the method 1200determines a relationship between a fluid velocity divergence of an electrical property of a transducer coupled to the vibratory element and a fluid velocity invariant viscosity of the fluid. The fluid velocity divergence in the electrical property may be due to a fluid velocity of the fluid. The sensor assembly of the method 1200 may be, for example, the sensor assembly 10 described above, although any suitable sensor assembly may be employed.
[0177] The fluid velocity divergence of the electrical property may be due to a fluid velocity of the fluid. Accordingly, the fluid velocity divergence may be proportional to the fluid velocity of the fluid. For example, the fluid velocity divergence of the electrical property can be proportional to a divergence in a displacement related parameter of the vibratory element and the divergence in the displacement related parameter of the vibratory element can be proportional to the fluid velocity.
[0178] Determining the relationship between the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element and the fluid velocity invariant viscosity may comprise determining a relationship between the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element and a viscosity error of a viscosity value of the fluid and a relationship between the viscosity error of the viscosity of the fluid and the fluid velocity invariant viscosity. For example, determining the relationship between the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element and the viscosity error of the viscosity value of the fluid can comprise determining, at two or more fluid velocities, a plurality of ordered pairs of the fluid velocity divergence in the electrical property and the viscosity error of the viscosity value of the fluid.
[0179] The method 1200 may further comprise determining the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element immersed in the fluid. Determining the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element immersed in the fluid may comprise determining the electrical property value of the transducer coupled to the vibratory element immersed in the fluid and comparing the electrical property value to a reference value of the electrical property.
[0180] It should be appreciated that the electrical property value can comprise at least one of a central tendency value and a dispersion value of the electrical property. Thecentral tendency value can comprise one of a mean, median, and mode and the dispersion value comprises one of a range, variance, and standard deviation. The electrical property value may be an aggregated electrical property value determined from a plurality of samples of the electrical property. The transducer being coupled to the vibratory element can comprise the transducer being affixed to the vibratory element.
[0181] The method 1200 can further comprise determining at least one fluid velocity compensating term based on the fluid velocity divergence in the electrical property for compensating a fluid velocity variant viscosity value with the at least one fluid velocity compensating term. At least one fluid velocity compensating term may comprise a fluid velocity compensating coefficient for the fluid velocity variant viscosity and / or a fluid velocity compensating constant. Determining the relationship between the divergence of the electrical property of the transducer coupled to the vibratory clement and the fluid velocity invariant viscosity of the fluid comprises determining a functional relationship between the fluid velocity invariant viscosity and a fluid velocity variant viscosity of the fluid. The functional relationship between the fluid velocity invariant viscosity value and the fluid velocity variant viscosity value comprises determining a fluid velocity compensating intercept. An exemplary functional relationship is described above with reference to Equation [8] although any suitable functional relationship may be employed.
[0182] The viscosity meter 5, meter electronics 20, system 1100, and methods 900, 1000, 1200 described above can compensate for fluid flow effects on a viscosity meter. In particular, the viscosity meter 5, the meter electronics 20, system 1100, and the methods 900, 1000, 1200 can provide a fluid velocity invariant viscosity value even if the viscosity meter 5 is immersed in a fluid with a varying fluid velocity. The compensation does not require knowledge of a fluid velocity value because a fluid velocity divergence in an electrical property can be proportional to the fluid velocity of the fluid. That is, a difference between a reference electrical property value, such as a mean and / or standard deviation of the electrical property value, from a reference electrical property value can be used to determine a correction of a fluid velocity variant viscosity value. For example, a functional relationship and / or fluid velocity correctionvalues for a functional relationship can be selected based on the fluid velocity divergence of the electrical property value.
[0183] The detailed descriptions of the above embodiments are not exhaustive descriptions of all embodiments contemplated by the inventors to be within the scope of the present description. Indeed, persons skilled in the art will recognize that certain elements of the above-described embodiments may variously be combined or eliminated to create further embodiments, and such further embodiments fall within the scope and teachings of the present description. It will also be apparent to those of ordinary skill in the art that the above-described embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the present description.
[0184] Thus, although specific embodiments are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the present description, as those skilled in the relevant art will recognize. The teachings provided herein can be applied to other embodiments for compensating for fluid flow effects on a viscosity meter and not just to the embodiments described above and shown in the accompanying figures. Accordingly, the scope of the embodiments described above should be determined from the following claims.
Claims
1. We claim:
1. A method for compensating for fluid flow effects on a viscosity meter, the method comprising:immersing, in a fluid, a vibratory element of a sensor assembly; and detecting a fluid velocity divergence of an electrical property of a transducer coupled to the vibratory element immersed in the fluid;wherein the fluid velocity divergence of the electrical property is due to a fluid velocity of the fluid.
2. The method of claim 1, wherein the fluid velocity divergence is proportional to the fluid velocity of the fluid.
3. The method of claim 1, wherein:the fluid velocity divergence of the electrical property is proportional to a divergence in a displacement related parameter of the vibratory element; andthe divergence in the displacement related parameter of the vibratory element is proportional to the fluid velocity.
4. The method of claim 3, wherein the transducer coupled to the vibratory element is a displacement sensor configured to sense the displacement related parameter of the vibratory element immersed in the fluid.
5. The method of claim 1 , wherein detecting the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element immersed in the fluid comprises:determining an electrical property value of the transducer coupled to the vibratory element immersed in the fluid; andcomparing the electrical property value to at least one threshold value.
6. The method of claim 5, wherein the electrical property value comprises at least one of a central tendency value and a dispersion value of the electrical property.
7. The method of claim 6, wherein:the central tendency value comprises one of a mean, median, and mode of the electrical property; andthe dispersion value comprises one of a range, variance, and standaid deviation of the electrical property.
8. The method of claim 7, wherein detecting the fluid velocity divergence of the electrical property comprises determining if at least one of the central tendency value and the dispersion value exceeds a corresponding threshold value.
9. The method of claim 6, wherein the electrical property value is an aggregated electrical property value determined from a plurality of samples of the electrical property.
10. The method of claim 1, wherein the transducer being coupled to the vibratory element comprises the transducer being affixed to the vibratory element.
11. The method of claim 1, further comprising:determining at least one fluid velocity compensating term based on the fluid velocity divergence of the electrical property; andcompensating a fluid viscosity variant value using the at least one fluid velocity compensating term.
12. The method of claim 11, wherein the at least one fluid velocity compensating term comprises at least one of:a fluid velocity compensating coefficient multiplied with the fluid velocity variant viscosity; anda fluid velocity variant viscosity intercept.
13. The method of claim 12, wherein compensating the fluid velocity variant viscosity value comprises utilizing the following equation:RCORR 21 -m+ B\lm+ C ,where:hcoRR is acorrected viscosity and is a fluid velocity invariant viscosity; pmis an uncorrected or measured viscosity and is the fluid velocity variant viscosity; andA, B, and C are fluid velocity constants, wherein A and B are fluid velocity compensating coefficients and C is a fluid velocity compensating intercept.
14. A viscosity meter (5, 1105) configured to compensate for fluid flow effects on the viscosity meter (5, 1105), the viscosity meter (5, 1105) comprising:a sensor assembly (10, 1110) having vibratory elements (130, 1113) immersed in a fluid; anda meter electronics (20, 1120) configured to execute a method according to one of the foregoing claims 1 through 13.
15. The viscosity meter (5, 1105) of claim 14, further comprising transducers (120, 1112) configured to sense a displacement related parameter of the vibratory elements (130, 1113).
16. A method for compensating for fluid flow effects on a viscosity meter, the method comprising:immersing, in a fluid, a vibratory element of a sensor assembly; and determining a relationship between a fluid velocity divergence of an electrical property of a transducer coupled to the vibratory element and a fluid velocity invariant viscosity of the fluid;wherein the fluid velocity divergence in the electrical property is due to a fluid velocity of the fluid.
17. The method of claim 16, wherein determining the relationship between the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element and the fluid velocity invariant viscosity comprises determining:a relationship between the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element and a viscosity error of a viscosity value of the fluid; anda relationship between the viscosity error of the viscosity of the fluid and the fluid velocity invariant viscosity.
18. The method of claim 17, wherein determining the relationship between the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element and the viscosity error of the viscosity value of the fluid comprises:determining, at two or more fluid velocities, a plurality of ordered pairs of the fluid velocity divergence in the electrical property and the viscosity error of the viscosity value of the fluid.
19. The method of claim 16, wherein the fluid velocity divergence is proportional to the fluid velocity of the fluid.
20. The method of claim 16, wherein:the fluid velocity divergence of the electrical property value is proportional to a divergence in a displacement related parameter; and the divergence in the displacement related parameter of the vibratory element is proportional to the fluid velocity.
21. The method of claim 20, wherein the transducer coupled to the vibratory element is a displacement sensor configured to measure the displacement related parameter of the vibratory element immersed in the fluid.
22. The method of claim 16, further comprising determining the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element immersed in the fluid.
23. The method of claim 22, wherein determining the fluid velocity divergence of the electrical property of the transducer coupled to the vibratory element immersed in the fluid comprises:determining the electrical property value of the transducer coupled to the vibratory element immersed in the fluid; andcomparing the electrical property value to a reference value of the electrical property.
24. The method of claim 16, wherein the electrical property value comprises at least one of a central tendency value and a dispersion value of the electrical property.
25. The method of claim 24, wherein:the central tendency value comprises one of a mean, median, and mode; and the dispersion value comprises one of a range, variance, and standaid deviation.
26. The method of claim 24, wherein the electrical property value is an aggregated electrical property value determined from a plurality of samples of the electrical property.
27. The method of claim 16, wherein the transducer being coupled to the vibratory element comprises the transducer being affixed to the vibratory element.
28. The method of claim 16, further comprising determining at least one fluid velocity compensating term based on the fluid velocity divergence in the electrical property for compensating a fluid velocity variant viscosity value with the at least one fluid velocity compensating term.
29. The method of claim 28, wherein the at least one fluid velocity compensating term comprises a fluid velocity compensating coefficient for the fluid velocity variant viscosity and / or a fluid velocity compensating constant.
30. The method of claim 28, wherein determining the relationship between the divergence of the electrical property of the transducer coupled to the vibratory element and the fluid velocity invariant viscosity of the fluid comprises determining a functional relationship between the fluid velocity invariant viscosity and a fluid velocity variant viscosity of the fluid.
31. The method of claim 30, wherein the functional relationship between the fluid velocity invariant viscosity value and the fluid velocity variant viscosity value comprises determining a fluid velocity compensating intercept.
32. The method of claim 31 , wherein the functional relationship comprises the following equation:where:hcoBR is acorrected viscosity and is the fluid velocity invariant viscosity; pmis an uncorrected or measured viscosity and is the fluid velocity variant viscosity; andA, B, and C are fluid velocity constants, wherein A and B are fluid velocity compensating coefficients and C is a fluid velocity compensating intercept.
33. A system (1100) for compensating for fluid flow effects on a viscosity meter, the system (1100) comprising:a viscosity meter (1105) having a sensor assembly (1110) comprising vibratory elements (1113) immersed in a fluid;a reference device (1140); anda calibration computer (1130) in communication with the viscosity meter (1105) and the reference device (1140), the calibration computer (1130) being configured to perform a method according to one of the foregoing claims