Coriolis flow meter with multiple actuators

Abstract

A system includes a flow tube configured to provide a flow path through the flow tube. The system also includes a plurality of actuators radially distributed around the flow tube, wherein a first actuator of the plurality of actuators is configured to drive a first oscillation in a first plane, and a second actuator of the plurality of actuators is configured to drive a second oscillation in a second plane. In addition, the system includes a plurality of sensor groups disposed on the flow tube, wherein each sensor group includes two or more sensors configured to sense the first oscillation, the second oscillation, or both.

Description

Technical Field

[0001] The present disclosure relates generally to Coriolis flow sensors. More particularly, the present disclosure relates to a Coriolis flow sensor assembly having multiple actuators that each drive an oscillation and, in certain embodiments, may include a flow tube housing to improve the accuracy of measurements performed by the Coriolis flow sensor. Background Art

[0002] Accurate measurement of the properties of fluids conveyed by flow systems is important for various applications, such as in bioprocessing systems and oil and gas pipelines. One technique for measuring fluid properties is by using flow rate. This allows measurements to be performed during fluid transport or flow, which is advantageous for reducing associated operating costs. That is, active flow systems can operate during measurements. Flow rate can be measured as volume flow rate or mass flow rate. If the density of the fluid is constant, the volume flow rate is accurate; however, this is not always the case, as density can change significantly with temperature, pressure, or composition. Thus, mass flow rate is typically more reliable for measuring fluid flow. One method for measuring mass flow rate is by a Coriolis flow sensor (e.g., a flow meter). In general, a Coriolis flow sensor measures mass flow rate via a Coriolis force, which is generated by the fluid as it moves through an oscillating tube. Summary of the invention

[0003] Certain embodiments comparable in scope to the originally claimed subject matter are summarized below. These embodiments are not intended to limit the scope of the claimed subject matter, but rather these embodiments are intended only to provide a brief overview of possible embodiments. Indeed, the present disclosure may include various forms that may be similar or different from the embodiments set forth below.

[0004] A system having a flow tube is provided herein, the flow tube being configured to provide a flow path through the flow tube. The system further comprises a plurality of actuators radially distributed around the flow tube, wherein a first actuator of the plurality of actuators is configured to drive a first oscillation in a first plane, and a second actuator of the plurality of actuators is configured to drive a second oscillation in a second plane. In addition, the system comprises a plurality of sensor groups disposed on the flow tube, wherein each sensor group comprises two or more sensors configured to sense the first oscillation, the second oscillation, or both.

[0005] A method is provided herein, the method comprising actuating a flow tube with a first actuator to cause the flow tube to oscillate in a first plane, the flow tube having a fluid flowing along a flow path. The method further comprises measuring a first oscillation of the flow tube in the first plane. Then, the method comprises actuating the flow tube with a second actuator to cause the flow tube to oscillate in a second plane. In addition, the method comprises measuring a second oscillation of the flow tube in the second plane. Further, the method comprises determining a property of the fluid based on the measured first oscillation and the measured second oscillation.

[0006] Provided herein is a system having a fluid flow component, the fluid flow component including a main pipe and a secondary pipe, wherein the fluid flow component is configured to provide a flow path through the main pipe, wherein the main pipe is substantially straight along the flow path, and wherein the secondary pipe is coaxial with the main pipe and forms a gap with the main pipe. The system also includes a plurality of actuators distributed radially around the flow pipe, wherein a first actuator of the plurality of actuators is configured to drive a first oscillation in a first plane, and a second actuator of the plurality of actuators is configured to drive a second oscillation in a second plane. In addition, the system includes a plurality of sensors disposed in the secondary pipe and configured to sense one or both of the first oscillation or the second oscillation. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] These and other features, aspects and advantages of the present disclosure will become better understood upon reading the following detailed description with reference to the accompanying drawings, in which like characters represent like parts throughout the figures, and in which:

[0008] Figure 1 is a block diagram of a Coriolis flow sensor system according to the present disclosure;

[0009] Figure 2 is a diagram of a flow tube of a Coriolis flow sensor assembly having multiple sensors and multiple actuators according to the present disclosure;

[0010] Figure 3 A flow chart showing a method for operating a Coriolis flow sensor according to the present disclosure;

[0011] Figure 4 is a block diagram of a Coriolis flow sensor system according to the present disclosure;

[0012] Figure 5 is a diagram of various oscillation axes of a flow tube of a Coriolis flow sensor according to the present disclosure;

[0013] Figure 6 is a diagram of a flow tube and flow tube housing of a Coriolis flow sensor assembly according to the present disclosure;

[0014] Figure 7showing a cross section of a flow tube and flow tube housing of a Coriolis flow sensor assembly according to the present disclosure; and

[0015] Figure 8 A complex oscillation of a flow tube according to the present disclosure is shown. DETAILED DESCRIPTION

[0016] One or more specific embodiments of the present disclosure will be described below. In order to provide a concise description of these embodiments, all features of the actual implementation may not be described in the specification. It should be understood that in the research and development of any such actual implementation, as in any engineering or design project, many implementation-specific decisions must be made to achieve the specific goals of the developer, such as, in accordance with system-related and business-related constraints (which may be different from one implementation to another). Moreover, it should be understood that such research and development work can be complex and time-consuming, but for those of ordinary skill who benefit from this disclosure, it will only be a routine task of design, production and manufacture.

[0017] When introducing elements of various embodiments of the present disclosure, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements. The terms "comprising," "including," and "having" are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0018] Coriolis flow sensors are useful in many applications involving fluid flow, such as bioprocessing systems. In general, Coriolis flow sensors operate by measuring the phase shift of one or more oscillating flow tubes, which is caused by the Coriolis force (which is caused by the fluid flowing inside the tube). It is beneficial to provide a Coriolis flow sensor design that increases the Coriolis force effect, which in turn leads to increased mass flow sensitivity and sensing amplitude (e.g., high signal-to-noise ratio). That is, the structural characteristics and arrangement of the components of the sensor assembly as provided herein can affect the sensitivity of the measurement.

[0019] Many methods of changing the geometry of the tube generally result in a large tube ring, which has no advantage in zero stability because external disturbances are also amplified (which in turn reduces sensor accuracy). In addition, many methods for Coriolis flow sensors designed for high-pressure fluid flows may use more rigid materials or increase the wall thickness of the pipe, which results in lower sensitivity of the Coriolis flow sensor. The relationship between the structure of the flow tube and the operating pressure of the fluid flowing through the flow tube is shown by Barlow's formula: t=(P*D) / (2*S), where t is the wall thickness, P is the relative pressure between the inside and outside of the flow tube, S is the allowable stress (e.g., the appropriate operating pressure of the flow tube), and D is the outer diameter of the flow tube. As the wall thickness increases, the bending stiffness of the flow tube increases, which reduces the oscillation amplitude that drives the Coriolis effect, which in turn reduces the sensitivity of the sensor and increases the signal-to-noise ratio. In addition, these configurations also take up additional space in the fluid flow system, and the annular geometry changes the fluid flow path, which affects pressure loss, flow rate, shear rate, entrapment, discharge, and wear.

[0020] The present disclosure relates to a Coriolis flow sensor assembly with improved sensitivity and low signal-to-noise ratio. The assembly may include a flow tube (e.g., a disposable flow tube), multiple actuators, and multiple sets of sensors. Each actuator drives the flow tube to oscillate in a corresponding plane, and each set of sensors is configured to measure the phase shift generated by the oscillation and the Coriolis force in a given plane. Measuring the oscillation in multiple different planes / dimensions can increase the certainty of the measurement.

[0021] Now turning to the diagram, Figure 1 1 is a diagram illustrating an embodiment of a Coriolis flow sensor system 10. The Coriolis flow sensor system 10 includes an electronic circuit 12 coupled to one or more actuators 14 and one or more sensors 16. The one or more actuators 14 and the sensors 16 are coupled to a flow tube 18.

[0022] The electronic circuit 12 includes a drive circuit 20 to trigger one or more actuators 16 to generate oscillations of a desired frequency and amplitude in the flow tube 18. The Coriolis flow sensor system 10 also includes a sensor circuit 22 to receive a Coriolis response from the flow tube 18. The electronic circuit 12 also includes a processor 24 to process the Coriolis response signal received from the sensor 16 to generate one or more measurement values ​​representing one or more properties of the fluid. These measurement values ​​are displayed via a user interface 26. The electronic circuit 12 also includes a memory 27 to store the measurement values ​​for further use and communication to store data useful to the drive circuit 20 and the sensor circuit 22.

[0023] In operation, a flow of fluid 28 is provided to the flow tube 18. The electronic circuit 12 triggers one or more actuators 14 to generate oscillations in the flow tube 18, which are transmitted to the fluid 28. The one or more actuators 14 are used to induce oscillations of appropriate amplitude in the desired frequency range in the fluid 28. Due to these oscillations and the flow of the fluid 28 through the flow tube 18, a Coriolis response (vibration amplitude and phase) is generated in the fluid and sensed by the sensor 16 through the flow tube 18. The sensed Coriolis response signal from the sensor 16 is transmitted to the electronic circuit 12 for further processing to obtain a measurement of one or more properties of the fluid including the fluid flow. The one or more sensors 16 are configured to provide a signal indicative of a Coriolis response caused by the fluid 28 flowing through the flow tube 18. The one or more sensors 16 may include, for example, an electromagnetic sensor or an optical sensor and associated components. Furthermore, sensor 16 may include separate sensing components, with a portion of sensor 16 disposed on flow tube 18 and a portion of sensor 16 spaced apart from flow tube 18 , and whereby sensor 16 is configured to measure a change in the physical distance between the components as a measure of oscillations of flow tube 18 .

[0024] The system 10 can be used to evaluate fluid properties in any fluid flow system. As disclosed, fluid properties can be evaluated during operation of various manufacturing and / or fluid flow processes. Some applications for the system 10 described herein include the fabrication of wafers in the semiconductor industry, and medical applications involving the use of organic fluids. Some of these are high purity applications, and the use of flow tubes 18 made of, for example, polymers or other chemically inert materials is advantageous in such applications. In some other applications, flow tubes 18 formed of electrically inert and low thermal conductivity materials (such as glass) are advantageous.

[0025] It will be appreciated by those skilled in the art that one or more components of the Coriolis flow sensor system may be configured as a disposable portion, and other components may be configured as a reusable resident portion. To this end, in embodiments in which certain components are disposable, the disposable components may be separated from the resident portion (e.g., by an operator using appropriate tools or by hand). For example, at least one of the one or more actuators 14, one or more sensors 16, or flow tubes 18 may be a disposable portion, and the other portions may be configured as a reusable resident portion. It will be appreciated by those skilled in the art that the disposable portion may be replaced at very low cost at intervals determined by specific process requirements. In addition, in some embodiments, the flow tube 18 may be changed without replacing the entire Coriolis flow sensor. The subsystem of disposable portions allows for highly accurate measurements to be obtained, reuses portions of the Coriolis flow sensor system 10, provides flexibility for single applications, and achieves cost and material savings.

[0026] The flow tube 18 can be constructed as a conduit with an internal passage that allows fluid flow, and can be formed into a shape including but not limited to a single, double or multiple ring structure, a split flow, a straight tube, a countercurrent or a co-current structure. In some embodiments, the flow tube 18 is made of a polymer that is not primarily affected by the oscillation mode (harmonic frequency) of the mechanical oscillator. In some other examples, the flow tube 18 is made of metal. In still other examples, the flow tube 18 is made of glass. In some examples, the flow tube material is customized according to the specific needs of the bioprocessing application such as temperature, pressure and fluid properties to be measured (e.g., corrosiveness). In addition, as provided herein, the flow tube 18 can be implemented with a wall thickness or material feature that promotes variable stiffness along its length. The flow tube 18 can be arranged to allow online fluid flow sensing for a fluid treatment system. Therefore, the flow tube can be fluidically connected to the fluid conduit of a larger fluid treatment system.

[0027] In some embodiments, the flow tube 18 may include additional structural features that may stabilize and improve the performance of the flow tube 18. Thus, the flow tube 18 and any additional structural features may be collectively referred to as a fluid flow assembly 31. For example, the fluid flow assembly 31 may include a base or housing configured to accommodate the flow tube 18, the actuator 14, and / or the sensor 16. Additionally, in embodiments where the flow tube 18 is disposable, the fluid flow assembly may include a connection point to which the end of the flow tube 18 may be attached and which fluidly couples the flow tube 18 to the fluid flow system 10 to allow in-line fluid flow. Furthermore, while the depicted embodiments are in the context of a straight flow tube 18, the fluid flow assembly 31 may also accommodate a curved or looped flow tube 18.

[0028] Figure 2 A flow tube 18 is shown coupled to a plurality of actuators 14 and a plurality of sensors 16. As discussed herein, the flow tube 18 provides a flow path 30 or flow axis (e.g., in the direction shown by the arrow). In general, the actuators 14 drive the flow tube 18 to oscillate in a corresponding plane 32, and a Coriolis effect is observed when a fluid 28 flows through the flow tube 18 along the flow path 30. The sensors 16 detect phase differences in the oscillations of the flow tube 18, which will be discussed in more detail below.

[0029] As shown, the flow tube 18 includes six actuators 14a, 14b, 14c, 14d, 14e, and 14f. Each actuator 14 is disposed on or near the flow tube 18 and drives oscillations in at least one plane 32. For example, actuator 14a drives oscillations of the flow tube 18 in plane 32a during operation. It should be understood that the oscillations of the flow tube 18 caused by the actuator 14 may occur primarily along a single plane, but may also be detected in other planes depending on the nature of the oscillations.

[0030] Another actuator 14b is radially offset from actuator 14a (e.g., approximately 45 degrees) and can drive oscillations in plane 32b. Additionally, another actuator 14c is radially offset from actuators 14b and 14a (e.g., approximately 45 and 90 degrees, respectively). Thus, actuator 14c can drive oscillations of the flow tube in a third plane 32c. It should be understood that the fluid flow assembly can include fewer or more actuators 14 and fewer or more sensors 16 than in the illustrated embodiment.

[0031] Although each actuator 14 is discussed as being radially offset in 45 degree increments, the radial offset may be any suitable amount. Also, although each actuator 14 is relatively positioned at the center of the flow tube 18 relative to the flow axis 30, it will be appreciated by one of ordinary skill in the art that the position of the actuator 14 may depend on the physical properties of the flow tube 18 and the type of oscillation (e.g., the order of the mode). Although only one actuator 14 is shown for each respective plane, in some embodiments, two actuators 14 may drive oscillations in the same plane 32.

[0032] As shown, the flow tube 18 includes six sensors 16a, 16b, 16c, 16d, 16e, and 16f disposed on an outer surface 34 of the flow tube 18. As shown, sensors 16a and 16b are disposed in plane 32a (e.g., coplanar), sensors 16c and 16d are disposed in plane 32b, and sensors 16e and 16f are disposed in plane 32c. In general, each sensor 16 in plane 32 will sense a Coriolis phase shift resulting from the fluid flowing along the flow path 30 and the oscillation driven by one or more actuators 14. For example, when the oscillator 14a drives the oscillation of the flow tube 18 along the plane 32a and the fluid flows along the flow path 30, there will be a phase shift in the oscillation due to the Coriolis effect. The detection of the oscillation may involve comparing the flow tube oscillations between two or more spaced apart sensors 16, which may be referred to as a sensor group 36. The sensor group 36 may include sensors spaced along the length of the flow tube 18 (eg, along the axis 30 ) and / or spaced circumferentially.

[0033] In general operation, each actuator 14 may drive the oscillation of the flow tube 18 in any order deemed appropriate to achieve the highest signal-to-noise ratio (eg, sequentially, in combination, etc.). Figure 31 is a flow chart illustrating an embodiment of a process 40 for operating a Coriolis flow sensor system 10 according to the present disclosure. It is to be understood that the steps discussed herein are exemplary only and that certain steps may be omitted or performed in a different order than described below. In some embodiments, the process 40 may be stored on the non-volatile memory 27 and executed by the processor 24 of the electronic circuit 12, or stored in other suitable memory and executed by other suitable processing circuits associated with the Coriolis flow sensor system 10 or separate suitable processing circuits.

[0034] As in Figure 3 In the illustrated embodiment, shown at box 42, the processor 24 sends a signal (e.g., a drive signal) that causes the actuator 14 to oscillate the flow tube 18 in a manner that can be detected in the first plane 32. For example, the actuator 14a can drive the flow tube 18 to oscillate in the plane 32a. When the fluid 28 flows through the flow tube 18, a Coriolis phase effect occurs, which induces a phase shift along the oscillating flow tube 18. Then, at box 44, the processor 24 measures a first Coriolis phase shift associated with the oscillation in the first plane 32 (e.g., plane 32a). That is, the sensor 16 is configured to measure the phase shift in the first plane 32 and can measure a signal or data indicative of a property of the fluid flowing through the flow tube 18. Changes in the Coriolis phase effect over time can indicate changes in fluid properties.

[0035] At box 46, the processor 24 sends a suitable signal that causes the actuator 14 to oscillate the flow tube 18 in the second plane 32. For example, the actuator 14b may drive the flow tube 18 to oscillate in the plane 32b. When the fluid 28 flows through the flow tube 18, a Coriolis phase effect occurs that induces a phase shift along the oscillating flow tube 18. Then, at box 48, the processor 24 measures a first Coriolis phase shift associated with the oscillation in the second plane 32 (e.g., plane 32b). That is, the sensor 16 configured to measure the phase shift in the first plane 32 may measure a signal or data indicative of a property of the fluid.

[0036] At block 50, the processor 24 determines a property of the fluid based on the Coriolis phase shift produced by the oscillations in the first and second planes 32 (e.g., 32a and 32b). In some embodiments, prior to reaching block 50, the processor 24 may send a suitable signal that causes the third actuator 14 (e.g., actuator 14c) to drive oscillations in the third plane 32c. Furthermore, the oscillations in the flow tubes mentioned in blocks 42 and 46 may be at respective first and second frequencies. Further, the oscillations may be in the same plane 32, but at different frequencies.

[0037] Thus, one embodiment of the present disclosure is directed to a Coriolis flow sensor assembly with improved sensitivity and low signal-to-noise ratio. The assembly may include a flow tube (e.g., a disposable flow tube), a plurality of actuators, and a plurality of sets of sensors. Each actuator is configured to drive the flow tube to oscillate in a plane, and each set of sensors is configured to measure a phase shift in a given plane caused by the oscillation and the Coriolis force.

[0038] In another embodiment, the present disclosure relates to a flow tube with a flow tube housing that reduces oscillatory force losses. In an embodiment, a Coriolis flow sensor system may include a flow tube housing that surrounds the flow tube. The flow tube housing includes a pressurized volume or gap between the flow tube and the flow tube housing, which can be used as a pressure volume (containment) and a barrier for the flow tube. That is, as shown in the Barlow formula discussed herein, the pressurized gap reduces the relative pressure P. In addition, the pressurized gap can minimize unwanted oscillations, such as oscillations in directions other than the oscillations driven by the actuator. Unwanted oscillations interfere with performance and reduce the SNR of the Coriolis flow sensor. For example, interference can produce a phase-shifted signal that is not generated by mass flow, which also oscillates and causes large data dispersion and lag. The flow tube housing can also reduce many structural changes performed to improve the performance of the Coriolis flow sensor, such as an annular configuration that introduces dead volume or unused volume. In addition, the present technology can facilitate thinner walls of the flow tube or allow less rigidity in the flow tube, which leads to increased sensitivity and SNR.

[0039] Figure 4 is a diagram illustrating an embodiment of a Coriolis flow sensor system 10. The Coriolis flow sensor system 10 includes an electronic circuit 12 coupled to one or more actuators 14 and one or more sensors 16. The one or more actuators 14 and sensors 16 are coupled to a flow tube 18. The flow tube 18 is enclosed within a flow tube housing 52, which also houses the actuators 14 and sensors 16 to form a Coriolis flow sensor assembly 53.

[0040] The electronic circuit 12 includes a drive circuit 20 to trigger one or more actuators 16 to generate oscillations of a desired frequency and amplitude in the flow tube 18. The Coriolis flow sensor system 10 also includes a sensor circuit 22 to receive a Coriolis response from the flow tube 18. The electronic circuit 12 also includes a processor 24 to process the Coriolis response signal received from the sensor 16 to generate one or more measurement values ​​representing one or more properties of the fluid. These measurement values ​​are displayed via a user interface 26. The electronic circuit 12 also includes a memory 27 to store the measurement values ​​for further use and communication to store data useful to the drive circuit 20 and the sensor circuit 22.

[0041] In operation, a flow of fluid 28 is provided to the flow tube 18. The electronic circuit 12 triggers one or more actuators 14 to generate oscillations in the flow tube 18, which are transmitted to the fluid 28. The oscillations in the flow tube 18 are relative to the flow tube housing 52, which remains substantially stationary. The one or more actuators 14 are used to induce oscillations of appropriate amplitude in the desired frequency range in the fluid 28. The flow tube housing 52 is pressurized with a liquid or gas and generally prevents the flow tube 18 from oscillating in directions or planes other than the intended oscillation direction. That is, some frequencies of the oscillation modes of the flow tube 18 may have partial overlap, and these other frequencies may reduce the amplitude of the intended oscillations. Thus, the oscillations induced (e.g., driven) by the actuator 14 may partially excite the undesirable mode. As discussed in more detail below, the pressurized flow tube housing 52 reduces or prevents undesirable oscillations, which may reduce the SNR of the intended oscillations.

[0042] Due to these oscillations and the flow of the fluid 28 through the flow tube 18, a Coriolis response (vibration amplitude and phase) is generated in the fluid and sensed by the sensor 16 through the flow tube 18. The sensed Coriolis response signal from the sensor 16 is transmitted to the electronic circuit 12 for further processing to obtain a measurement of one or more properties of the fluid including the fluid flow. The one or more sensors 16 are configured to provide a signal indicative of the Coriolis response caused by the fluid 28 flowing through the flow tube 18. The one or more sensors 16 may include, for example, an electromagnetic sensor or an optical sensor and associated components.

[0043] The system 10 can be used to evaluate fluid properties in any fluid flow system. As disclosed, fluid properties can be evaluated during operation of various manufacturing and / or fluid flow processes. Some applications for the system 10 described herein include the fabrication of wafers in the semiconductor industry, and medical applications involving the use of organic fluids. Some of these are high purity applications, and the use of flow tubes 18 made of, for example, polymers or other chemically inert materials is advantageous in such applications. In some other applications, flow tubes 18 formed of electrically inert and low thermal conductivity materials (such as glass) are advantageous.

[0044] It will be appreciated by those skilled in the art that one or more components of the sensor assembly 14 may be configured as a disposable portion and other components may be configured as a reusable resident portion. To this end, in embodiments in which certain components are disposable, the disposable components may be separated from the resident portion (e.g., by an operator using appropriate tools or by hand). For example, at least one of the one or more actuators 14, one or more sensors 16, or flow tubes 18 may be a disposable portion and the other portions may be configured as a reusable resident portion. It will be appreciated by those skilled in the art that the disposable portion may be replaced at very low cost at intervals determined by specific process requirements. In addition, in some embodiments, the flow tube 18 may be changed without replacing the entire Coriolis flow sensor. The subsystem of disposable portions allows for highly accurate measurements to be obtained, portions of the Coriolis flow sensor system 10 to be reused, flexibility to be provided for single applications, and cost and material savings to be achieved.

[0045] As discussed herein, the flow tube 18 can be constructed as a conduit with an internal passage that allows fluid flow, and can be formed into shapes including but not limited to single, double or multiple ring structures, split flow, straight tubes, countercurrent or co-current structures. In some embodiments, the flow tube 18 is made of a polymer that is not primarily affected by the oscillation mode (harmonic frequency) of the mechanical oscillator. In some other examples, the flow tube 18 is made of metal. In still other examples, the flow tube 18 is made of glass. In some examples, the flow tube material is customized according to the specific needs of the bioprocessing application such as temperature, pressure and fluid properties to be measured (e.g., corrosiveness). In addition, as provided herein, the flow tube 18 can be implemented with a wall thickness or material feature that promotes variable stiffness along its length. The flow tube 18 can be arranged to allow online fluid flow sensing for a fluid treatment system. Therefore, the flow tube can be fluidically connected to the fluid conduit of a larger fluid treatment system.

[0046] As discussed above, Figure 4 The flow tube housing 52 shown in FIG. 5 substantially reduces the undesirable oscillation effects. Figure 5is a schematic diagram of a transverse axis 56 and a vertical axis 54 along the flow tube 18. As shown, the oscillation 58 occurs in a plane 60 that crosses the vertical axis 54 and the flow axis 30. Undesirable harmonic modes (e.g., structural modes) may occur along the axes 54 and 56 and cause Coriolis deflection shapes that may reduce the amplitude of the oscillation 58. In order to attenuate or shift the frequency of the undesirable harmonic modes of the flow tube 18, additional structural features may be added. Structural features along certain axes (e.g., 54 and 56) may provide independent effects on different vibration modes with variable cross-sections, which adjust the undesirable harmonic modes (e.g., shift the frequency of the harmonic modes up, shift the frequency down, or reduce the amplitude) until the undesirable harmonic mode effects are negligible, resulting in increased sensitivity and robustness of the Coriolis flow sensor assembly. The characteristics (e.g., modal characteristics) that alter the undesirable harmonic modes may have various designs, structures, and properties to address different modes.

[0047] Figure 6 is a partial cross-sectional view of a Coriolis flow sensor assembly 53 that includes a flow tube 18 (e.g., a primary tube) and a flow tube housing 52 (e.g., a secondary tube) of the Coriolis flow sensor system 10. The flow tube includes a plurality of sensors 16 disposed on an outer surface 34 of the flow tube and operable as described herein. As shown, the flow tube housing 52 is coaxial with the flow tube 18 (e.g., surrounding the flow path 30). In addition, the flow tube housing 52 surrounds the flow tube 18 such that a gap 62 is formed between the flow tube housing 52 and the flow tube 18. As discussed herein, the gap 62 can be pressurized with a fluid (e.g., a liquid or a gas).

[0048] As shown, the gap 62 generally surrounds a portion 64 of the flow tube 18 along the flow path 30. Generally, the portion 64 surrounded by the gap 62 will have a suitable length of the flow tube 18 portion 64 in which the flow tube 18 can oscillate under operation (e.g., 20%, 40%, 60%, 80%, less than 100% of the total length of the tube). In one embodiment, the flow tube shell 52 contacts (e.g., is attached to) an end 66 of the flow tube 18, or is coupled to a coupling joint 67 that couples the flow tube 18 to the system 10, and the connection between the flow tube shell 52 and the flow tube 18 at the end 66 can maintain the pressure within the gap 62. The flow tube 18 can be constructed of a more flexible material than the flow tube shell 52. In certain embodiments, the flow tube assembly 53 can be separate from the system 10 and can be provided as an integral assembly.

[0049] As shown, the transmitter 68 is generally aligned on the central axis 70 of the flow tube housing 52 and the flow tube 18. As discussed herein, the transmitter 68 sends a signal to the actuator 14, which drives the oscillation of the flow tube at a certain frequency. In addition, the transmitter 68 can receive signals from the sensor 16. Moreover, the transmitter 68 can include circuitry for managing (e.g., sending signals) to the sensor 16 and the actuator 14. Still further, the transmitter 68 can provide an interface to a user through a visual display or over an electronic interface (e.g., RS-232).

[0050] like Figure 6 , the actuator 14 is disposed about the central axis 70, it will be appreciated by one of ordinary skill in the art that the location of the actuator 14 may depend on the mode of oscillation. For example, a suitable location for the actuator 14 may be a certain fraction along the portion 64 of the flow tube 18. Furthermore, as discussed herein, the Coriolis flow system 10 may include a plurality of actuators 14, each of which drives oscillations at a certain frequency / position.

[0051] Figure 7 A cross section along the flow path 30 of the flow tube 18 is shown, as shown in FIG. Figure 6 , the flow tube 18 is surrounded by the flow tube shell 52. As shown, the outer surface 34 of the flow tube 18 is in contact with the pressurization gap 62. The distance 69 between the flow tube shell 52 and the outer surface 34 of the flow tube 18 can be any suitable distance 69 that does not restrict the oscillation of the flow tube 18. Figure 7 Also shown is a transition region 72 between the flow tube housing 52 and one end 66 of the flow tube 18. The transition region 72 between the end 66 where the flow tube 18 contacts the flow tube housing 52 and the portion 64 having the gap 62 may have any suitable shape.

[0052] Thus, another embodiment of the present disclosure is directed to a Coriolis flow sensor system having a flow tube and a flow tube housing. In general, a pressurized gap between the flow tube and the flow tube housing reduces unwanted oscillation effects. One or more actuators and one or more sensors may be disposed within the flow tube housing. The sensors may be disposed on the flow tube, and the actuators may be disposed radially around the flow tube around the flow path.

[0053] As discussed herein, the Coriolis flow sensor system 10 may include multiple actuators 14 and multiple sensors 16. Thus, multiple actuators 14 may drive multiple oscillations. In some embodiments, complex oscillations may be driven at various frequencies. Figure 8 The oscillation position 74 (eg, as a function of time) is shown with three different oscillation frequencies 76, 78, and 80. Figure 5 54 and 56 shown in FIG. 1 ). That is, the oscillation of the flow tube 18 may be a combination of multiple oscillations.

[0054] This written description uses examples, including the best mode, and also enables any person skilled in the art to practice embodiments of the disclosure, including making and using any devices or systems and performing any combined methods. The patentable scope is defined by the claims, and may include other examples that occur to one skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

1. A system, comprising: a flow tube configured to provide a flow path therethrough; a plurality of actuators radially distributed about the flow tube, wherein a first actuator of the plurality of actuators is configured to drive a first oscillation in a first plane, a second actuator of the plurality of actuators is configured to drive a second oscillation in a second plane, and a third actuator of the plurality of actuators is configured to drive a third oscillation in a third plane, wherein the frequency of each oscillation driven by each actuator is different; as well as A plurality of sensor groups are disposed on the flow tube, wherein each sensor group includes two or more sensors configured to sense the first oscillation, the second oscillation, or a third oscillation.

2. The system according to claim 1, characterized in that The second actuator is radially offset from the first actuator by approximately 45 degrees, and the third actuator is radially offset from the first actuator by approximately 90 degrees.

3. The system according to claim 1, characterized in that The first actuator is disposed around the flow tube opposite to a different actuator of the plurality of actuators.

4. The system according to claim 1, characterized in that Each sensor group includes a first sensor spaced apart from a second sensor along the length of the flow tube.

5. The system according to claim 1, characterized in that The flow tube is at least partially surrounded by a pressurized flow tube shell coaxial with the flow tube.

6. The system according to claim 1, characterized in that The flow tube and each sensor of the plurality of sensors are configured to be reversibly coupled to a fluid flow component.

7. The system according to claim 1, characterized in that Each oscillation is driven at a central portion of the flow tube.

8. A method comprising: actuating a flow tube with a first actuator to cause the flow tube to oscillate in a first plane, the flow tube having a fluid flowing along a flow path; measuring a first oscillation of the flow tube in the first plane; actuating the flow tube with a second actuator to cause the flow tube to oscillate in a second plane; measuring a second oscillation of the flow tube in the second plane; actuating the flow tube with a third actuator to cause the flow tube to oscillate in a third plane; as well as measuring a third oscillation of the flow tube in the third plane; wherein the first frequency, the second frequency, and the third frequency of each oscillation driven by each actuator are different; as well as A property of the fluid is determined based on the measured first oscillation, the measured second oscillation, and the measured third oscillation.

9. The method according to claim 8, characterized in that The first plane is radially offset from the second plane.

10. The method according to claim 8, characterized in that Determining a property of the fluid is based at least in part on the amplitudes of the first oscillation and the second oscillation.

11. A system, comprising: a fluid flow assembly comprising a main pipe and a sub-pipe, wherein the fluid flow assembly is configured to provide a flow path through the main pipe, wherein the main pipe is substantially straight along the flow path, and wherein the sub-pipe is coaxial with the main pipe and forms a gap with the main pipe; a plurality of actuators radially distributed around the main tube, wherein a first actuator of the plurality of actuators is configured to drive a first oscillation in a first plane, a second actuator of the plurality of actuators is configured to drive a second oscillation in a second plane, and a third actuator of the plurality of actuators is configured to drive a third oscillation in a third plane, wherein the frequency of each oscillation driven by each actuator is different; as well as A plurality of sensors are disposed within the secondary pipe and configured to sense one or more of the first oscillation, the second oscillation, or the third oscillation.

12. The system according to claim 11, characterized in that The plurality of sensors are disposed on the main pipe.

13. The system according to claim 11, characterized in that The gap surrounds at least a portion of the main tube along the flow path.

14. The system according to claim 11, characterized in that The gap is pressurized with a gas.

15. The system according to claim 11, characterized in that The gap is pressurized with a liquid.

16. The system according to claim 11, characterized in that The main pipe has a thinner wall or is less rigid than the sub-pipe.

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