Vibrating type meter comprising wire flexures extending from the meter coils, and related method

Abstract

A sensor assembly (10) for a vibrating meter (50) is provided. The sensor assembly (10) includes one or more conduits (103A, 103B). The sensor assembly (10) also includes one or more sensor components including one or more of a driver (104), a first pick-off sensor (105), and a second pick-off sensor (105') coupled to the one or more conduits (103A, 103B). A wire flexure (300) extends from the coil (107) and is electrically coupled to meter electronics (20). The wire flexure (300) is configured to comprise a length (L) that confers a resonant frequency to the wire flexure (300) that is higher than the highest drive frequency of the sensor assembly (10).

Description

[0001] VIBRATING TYPE METER COMPRISING WIRE FLEXURES EXTENDING FROM THE METER COILS, AND RELATED METHOD

[0002] TECHNICAL FIELD

[0003] The embodiments described below relate to vibrating meters, and more particularly, to improved electrical flexures for a vibrating meter.

[0004] BACKGROUND OF THE INVENTION

[0005] Vibrating sensors, such as for example, vibrating densitometers and Coriolis flowmeters are generally known, and are used to measure mass flow and other information related to materials flowing through a conduit in the flowmeter. Exemplary Coriolis flowmeters are disclosed in U.S. Patent 4,109,524, U.S. Patent 4,491,025, and Re. 31,450. These flowmeters have meter assemblies with one or more conduits of a straight or curved configuration. Each conduit configuration in a Coriolis mass flowmeter, for example, has a set of natural vibration modes, which may be of simple bending, torsional, or coupled type. Each conduit can be driven to oscillate at a preferred mode. When there is no flow through the flowmeter, a driving force applied to the conduit(s) causes all points along the conduit(s) to oscillate with identical phase or with a small “zero offset”, which is a time delay measured at zero flow.

[0006] As material begins to flow through the conduit(s), Coriolis forces cause each point along the conduit(s) to have a different phase. For example, the phase at the inlet end of the flowmeter lags the phase at the centralized driver position, while the phase at the outlet leads the phase at the centralized driver position. Pickoffs on the conduit(s) produce sinusoidal signals representative of the motion of the conduit(s). Signals output from the pickoffs are processed to determine the time delay between the pickoffs, which is known as the AT. The time delay between the two or more pickoffs is proportional to the mass flow rate of material flowing through the conduit(s).

[0007] A meter electronics connected to the driver generates a drive signal to operate the driver and also to determine a mass flow rate and / or other properties of a process material from signals received from the pickoffs. The driver may comprise one of many well- known arrangements; however, a magnet and an opposing drive coil have received great success in the flowmeter industry. An alternating current is passed to the drive coil for vibrating the conduit(s) at a desired conduit amplitude and frequency. It is also known in the art to provide the pickoffs as a magnet and coil arrangement very similar to the driver arrangement.

[0008] Flexures are often employed to connect vibratory transducers, such as drivers and pickoffs, to the meter electronics. Flexures are electro-mechanical components used to provide a flexible connection between two electronic components. They generally allow movement of electronic components with respect to each other, providing some level of flexibility while still maintaining mechanical stability and electrical continuity.

[0009] Monel ribbons have often been employed as flowmeter flexures. Monel is a nickelcopper alloy that is known for its strength, toughness, corrosion resistance, and flexibility, which make it suitable for use in harsh environments, such as what may be encountered by flowmeter installation environments and the internal vibratory stresses found in vibratory flowmeter assemblies. Due to the shape of Monel ribbons, these flexures limit side to side vibration, and instead force more of a rolling motion to occur when energized.

[0010] FIG. 1 shows a prior art vibrating meter 50 having conduits 103A, 103B, and including the meter electronics 20 and a sensor assembly 200. Common reference numbers are used for components of the prior art sensor assembly 200 that also comprise components of embodiments of the sensor assembly 10 provided. The embodiment shown in FIG. 1 has the front half of the case 15 removed in order to illustrate the interior components. The sensor components are coupled to a bus 201, and are in electrical communication with the meter electronics 20 via the bus 201. The sensor components may include one or more of a driver 104, pick-off sensors 105, 105’. The bus 201 can sensor component ribbon flexures 210-212’ that communicate between the leads 130 and the sensor components. These are typically the aforementioned Monel ribbons. The leads 130 provide an electrical communication path between the bus 201 and the meter electronics 20, for example. Therefore, the bus 201 provides electrical communication between the sensor components and devices external to the sensor assembly 200, such as the meter electronics 20.

[0011] In order to reduce the size of flowmeter assemblies, alternatives to Monel ribbons are employed. For example, relatively small gauge copper magnet wire that is continuous from the windings of transducer coils has been used to bridge the gap between the transducers and nearby printed circuit boards (PCBs), thus forming an extremely compact flexure. This scheme would result in two flexures that communicate with every coil within a Coriolis sensor. These flexures are used to communicate a signal from the meter electronics to a corresponding coil, be it a driver or pickoff sensor coil.

[0012] Unfortunately, changes in the configuration of magnet wire flexures can have drastic impact on signals, can shift measurements, and can thus cause failure. A critical change that may be realized occurs when wire flexures vibrate near resonance. Vibration at the resonant frequency in one or more flexures within a meter has been shown to shift Delta T measurements. This, of course, renders flow measurements less accurate.

[0013] The flexures are connected to coils which comprise magnets within their assemblies. Even with magnetic keepers present, stray magnetic fields are proximate the coils. A vibrating wire passing through a stray magnetic field induces a voltage, and that additional voltage induced in the flexures impacts the signal measured from that coil.

[0014] Vibrating flexures also increase the potential for fatigue. Undcsircd bends, dents, and inconsistencies can be introduced to flexures during the assembly process. Flexures that have dents on the surface are more likely to fail under vibration. The direction of the flexure arc can also lower the resonant frequency making it more likely to vibrate at the drive coil frequency. Different lengths of flexures result in different resonant frequencies for the corresponding flexure. Increasing the length can also move the resonant frequency of the flexure towards the drive frequency of the meter.

[0015] Furthermore, the shape of the flexure arc can create the circumstance where two flexures on a coil assembly make contact. Contact between two flexures can cause a short within the circuit which significantly impacts the signal, and therefore impacts the measurement the sensor reports.

[0016] The embodiments described below overcome these and other problems and an advance in the art is achieved. The embodiments described below provide an improved flexure that is resistant to deleterious resonances that negatively affect flowmeter operation and accuracy.

[0017] SUMMARY OF THE INVENTION

[0018] According to an embodiment, a sensor assembly for a vibrating meter is provided.

[0019] The sensor assembly comprises one or more conduits, and one or more sensor components including one or more of a driver, a first pick-off sensor, and a second pick-off sensor coupled to the one or more conduits, wherein the one or more sensor components each comprise a coil. A wire flexure extends from the coil and electrically coupled to meter electronics. The wire flexure is configured to comprise a length that confers a resonant frequency to the wire flexure that is higher than the highest drive frequency of the sensor assembly.

[0020] According to an embodiment, a method for configuring a sensor assembly for a vibrating meter is provided. The method comprises providing one or more conduits, and providing one or more sensor components including one or more of a driver, a first pickoff sensor, and a second pick-off sensor coupled to the one or more conduits, wherein the one or more sensor components each comprise a coil. A wire flexure extends from the coil to electrically couple the coil to meter electronics. The wire flexure is configured to comprise a length that confers a resonant frequency to the wire flexure that is higher than the highest drive frequency of the sensor assembly.

[0021] ASPECTS

[0022] According to an aspect, a sensor assembly for a vibrating meter comprises one or more conduits, and one or more sensor components including one or more of a driver, a first pick-off sensor, and a second pick-off sensor coupled to the one or more conduits, wherein the one or more sensor components each comprise a coil. A wire flexure extends from the coil and electrically coupled to meter electronics. The wire flexure is configured to comprise a length that confers a resonant frequency to the wire flexure that is higher than the highest drive frequency of the sensor assembly.

[0023] Preferably, a flexure natural frequency ratio value is less than or equal to 0.8, wherein the flexure natural frequency ratio comprises the highest drive frequency of the sensor assembly divided by a natural frequency of the wire flexure.

[0024] Preferably, a straight wire approximation ratio is greater than or equal to 4.5, wherein the straight wire approximation ratio comprises a gap length between the coil where the wire flexure emanates from the coil and a point of attachment of the wire flexure divided by a height of the flexure arc.

[0025] Preferably, a dampening compound is placed on the wire flexure proximate a point of attachment of the wire flexure end. Preferably, the wire flexure forms an arc between the coil and a point of attachment of the wire flexure, wherein the orientation of the wire flexure is vertical, such that the arc’s curvature curves into a direction of the meter’s drive axis and lies substantially within the flowmeter’ s XY plane.

[0026] Preferably, the wire flexure forms an arc between the coil and a point of attachment of the wire flexure, wherein the orientation of the wire flexure is horizontal, such that the arc’s curvature curves into a direction perpendicular to the meter’s drive axis and lies substantially within the flowmeter’s XZ plane.

[0027] Preferably, the wire flexure forms an arc between the coil and a point of attachment of the wire flexure, wherein the orientation of the wire flexure is between horizontal and vertical.

[0028] Preferably, a straight wire approximation ratio is less than 4.5, wherein the straight wire approximation ratio comprises a gap length between the coil where the wire flexure emanates from the coil and a point of attachment of the wire flexure end divided by a height of the flexure arc.

[0029] According to an aspect, a method for configuring a sensor assembly for a vibrating meter comprises providing one or more conduits, and providing one or more sensor components including one or more of a driver, a first pick-off sensor, and a second pickoff sensor coupled to the one or more conduits, wherein the one or more sensor components each comprise a coil. A wire flexure extends from the coil to electrically couple the coil to meter electronics. The wire flexure is configured to comprise a length that confers a resonant frequency to the wire flexure that is higher than the highest drive frequency of the sensor assembly.

[0030] Preferably, a flexure natural frequency ratio value is less than or equal to 0.8, wherein the flexure natural frequency ratio comprises the highest drive frequency of the sensor assembly divided by a natural frequency of the wire flexure.

[0031] Preferably, a straight wire approximation ratio is greater than or equal to 4.5, wherein the straight wire approximation ratio comprises a gap length between the coil where the wire flexure emanates from the coil and a point of attachment of the wire flexure divided by a height of the flexure arc.

[0032] Preferably, the method comprises placing a dampening compound on the wire flexure proximate a point of attachment of the wire flexure end. Preferably, the method comprises forming an arc with the wire flexure between the coil and a point of attachment of the wire flexure and orienting the wire flexure vertically, such that the arc’s curvature curves into a direction of the meter’s drive axis and lies substantially within the flowmeter’s XY plane.

[0033] Preferably, the method comprises forming an arc with the wire flexure between the coil and a point of attachment of the wire flexure, and orienting the wire flexure horizontally, such that the arc’s curvature curves into a direction perpendicular to the meter’s drive axis and lies substantially within the flowmeter’s XZ plane.

[0034] Preferably, the method comprises forming an arc between the coil and a point of attachment of the wire flexure, wherein the orientation of the wire flexure is between horizontal and vertical.

[0035] Preferably, a straight wire approximation ratio is less than 4.5, wherein the straight wire approximation ratio comprises a gap length between the coil where the wire flexure emanates from the coil and a point of attachment of the wire flexure end divided by a height of the flexure arc.

[0036] BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 shows a prior art sensor assembly;

[0038] FIG. 2 shows a vibratory meter according to an embodiment;

[0039] FIG. 3 shows a meter electronics according to an embodiment;

[0040] FIG. 4 illustrates a graph indicating the wire flexure lengths and effect on natural frequency;

[0041] FIG. 5 illustrates a graph indicating how drive frequency affects specific wire lengths;

[0042] FIG. 6 illustrates a wire flexure attachment to a solder pad of a printed circuit board;

[0043] FIGS. 7A and 7B illustrate vertically oriented wire flexures according to an embodiment; and

[0044] FIG. 8 illustrates horizontally oriented wire flexures according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0045] FIGS. 1 - 8 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 a sensor assembly, brace bars, drivers, and pickoff sensors. 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 form multiple variations of embodiments. As a result, the embodiments described below are not limited to the specific examples described below, but only by the claims and their equivalents.

[0046] FIG. 2 shows a flowmeter 5 according to an embodiment. The flowmeter 5 comprises a sensor assembly 10 and meter electronics 20. The meter electronics 20 is connected to the sensor assembly 10 via leads 100 and is configured to provide measurements of one or more of a density, mass flow rate, volume flow rate, totalized mass flow, temperature, or other measurements or information over a communication path 26. The flowmeter 5 can comprise a Coriolis mass flowmeter or other vibratory flowmeter. It should be apparent to those skilled in the art that the flowmeter 5 can comprise any manner of flowmeter 5, regardless of the number of drivers, pick-off sensors, flow conduits, or the operating mode of vibration.

[0047] The sensor assembly 10 includes apair of flanges 101 and 101', manifolds 102 and 102', a driver 104, pick-off sensors 105 and 105', and flow conduits 103A and 103B. The driver 104 and the pick-off sensors 105 and 105' are connected to the flow conduits 103A and 103B. Pickoff sensor 105 may also be referred to as the left pick-off (LPO) and pickoff sensor 105’ may also be referred to as the right pick-off (RPO).

[0048] The flanges 101 and 10T are affixed to the manifolds 102 and 102’. The manifolds 102 and 102' can be affixed to opposite ends of a spacer 106 in some embodiments. The spacer 106 maintains the spacing between the manifolds 102 and 102'. When the sensor assembly 10 is inserted into a pipeline (not shown) which carries the process fluid being measured, the process fluid enters the sensor assembly 10 through the flange 101, passes through the inlet manifold 102 where the total amount of process fluid is directed to enter the flow conduits 103A and 103B, flows through the flow conduits 103A and 103B and back into the outlet manifold 102', where it exits the sensor assembly 10 through the flange 101'.

[0049] The process fluid can comprise a liquid. The process fluid can comprise a gas. The process fluid can comprise a multi-phase fluid, such as a liquid including entrained gases and / or entrained solids, for example without limitation. The flow conduits 103 A and 103B are selected and appropriately mounted to the inlet manifold 102 and to the outlet manifold 102' so as to have substantially the same mass distribution, moments of inertia, and elastic moduli about the bending axes W-W and W'-W', respectively. The flow conduits 103A and 103B extend outwardly from the manifolds 102 and 102' in an essentially parallel fashion.

[0050] The flow conduits 103A and 103B are driven by the driver 104 in opposite directions about the respective bending axes W and W' and at what is termed the first out of phase bending mode of the flowmeter 5. The driver 104 may comprise one of many well-known arrangements, such as a magnet mounted to the flow conduit 103 A and an opposing coil mounted to the flow conduit 103B. An alternating current is passed through the opposing coil to cause both conduits to oscillate. A suitable drive signal is applied by the meter electronics 20 to the driver 104 via lead 110. Other driver devices are contemplated and are within the scope of the description and claims.

[0051] The meter electronics 20 receives sensor signals on leads 111 and 111', respectively. The meter electronics 20 produces a drive signal on lead 110 which causes the driver 104 to oscillate the flow conduits 103A and 103B. Other sensor devices are contemplated and are within the scope of the description and claims.

[0052] The meter electronics 20 processes the left and right velocity signals from the pickoff sensors 105 and 105' in order to compute a flow rate, among other things. The communication path 26 provides an input and an output means that allows the meter electronics 20 to interface with an operator or with other electronic systems. The description of FIG. 2 is provided merely as an example of the operation of a flowmeter and is not intended to limit the teaching of the present invention. In embodiments, single tube and multi-tube flowmeters having one or more drivers and pickoffs are contemplated.

[0053] The meter electronics 20 in one embodiment is configured to vibrate the flow conduit 103A and 103B. The vibration is performed by the driver 104. The meter electronics 20 further receives resulting vibrational signals from the pickoff sensors 105 and 105'. The vibrational signals comprise a vibrational response of the flow conduits 103A and 103B. The meter electronics 20 processes the vibrational response and determines a response frequency and / or phase difference. The meter electronics 20 processes the vibrational response and determines one or more flow measurements, including a mass flow rate and / or density of the process fluid. Other vibrational response characteristics and / or flow measurements are contemplated and are within the scope of the description and claims.

[0054] In one embodiment, the flow conduits 103 A and 103B comprise substantially omega-shaped flow conduits, as shown. Alternatively, in other embodiments, the flowmeter can comprise substantially straight flow conduits, U-shaped conduits, deltashaped conduits, etc. Additional flowmeter shapes and / or configurations can be used and are within the scope of the description and claims.

[0055] FIG. 3 is a block diagram of the meter electronics 20 of a flowmeter 5 according to an embodiment. In operation, the flowmeter 5 provides various measurement values that may be outputted including one or more of a measured or averaged value of mass flow rate, volume flow rate, individual flow component mass and volume flow rates, and total flow rate, including, for example, both volume and mass flow.

[0056] The flowmeter 5 generates a vibrational response. The vibrational response is received and processed by the meter electronics 20 to generate one or more fluid measurement values. The values can be monitored, recorded, saved, totaled, and / or output.

[0057] The meter electronics 20 includes an interface 220, a processing system 203 in communication with the interface 220, and a storage system 204 in communication with the processing system 203. Although these components are shown as distinct blocks, it should be understood that the meter electronics 20 can be comprised of various combinations of integrated and / or discrete components.

[0058] The interface 220 is configured to communicate with the sensor assembly 10 of the flowmeter 5. The interface 220 may be configured to couple to the leads 100 (see FIG. 1) and exchange signals with the driver 104, pickoff sensors 105 and 105', and temperature sensors (not shown), for example. The interface 220 may be further configured to communicate over the communication path 26, such as to external devices. The processing system 203 can comprise any manner of processing system. The processing system 203 is configured to retrieve and execute stored routines in order to operate the flowmeter 5. The storage system 204 can store routines including a flowmeter routine 205. Other measurement / processing routines are contemplated and are within the scope of the description and claims. The storage system 204 can store measurements, received values, working values, and other information. In some embodiments, the storage system stores a mass flow (m) 221, a density (p) 225, a viscosity (p) 223, a temperature (T) 224, a drive gain 226, a transducer voltage 227, and any other variables known in the art.

[0059] The flowmeter routine 205 can produce and store fluid quantifications and flow measurements. These values can comprise substantially instantaneous measurement values or can comprise totalized or accumulated values. For example, the flowmeter routine 205 can generate mass flow measurements and store them in the mass flow 221 storage of the storage system 204, for example. The flowmeter routine 205 can generate density 225 measurements and store them in the density 225 storage, for example. The mass flow 221 and density 225 values arc determined from the vibrational response, as previously discussed and as known in the art. The mass flow and other measurements can comprise a substantially instantaneous value, can comprise a sample, can comprise an averaged value over a time interval, or can comprise an accumulated value over a time interval. The time interval may be chosen to correspond to a block of time during which certain fluid conditions are detected, for example a liquid-only fluid state, or alternatively, a fluid state including liquids and entrained gas. In addition, other mass flow and related quantifications are contemplated and are within the scope of the description and claims.

[0060] In the embodiments presented herein, wire flexures 300 are utilized in manners that improve the performance of sensor assemblies 10. The vibrations induced within the wire flexure 300 can cause both structure failure and the communication of inaccurate signals. The range of acceptable flexure lengths must be controlled, and acceptable lengths may vary depending on the particular aspects of the flowmeter. In an embodiment, a wire flexure 300 is configured to have a sufficiently higher resonant frequency than the drive frequency of the sensor assembly 10. This is accomplished by adjusting the length, shape, orientation, and environment of the flexure, as will be further discussed. The length of the wire flexures 300 must be within a certain range to ensure that failure does not occur, but also so all the resonant frequencies of the flexure are higher than the flowmeter's drive frequency. The first natural frequency is the lowest resonant frequency, and so if the first natural frequency of the wire flexure 300 is sufficiently higher than the drive frequency, none of the wire flexure modes will be reached. If a wire flexure mode is excited, amplified vibration of the flexure will occur.

[0061] Of course, since the wire flexures are coupled to a vibratory structure, there will always be forced vibration of the wire flexures. Another issue arises when this forced vibration is near the wire flexure's 300 resonant frequency. In an embodiment, the maximum length of wire flexure allowable for every drive frequency encountered in a flowmeter is calculated. In an example embodiment, Equation 1 is employed. However, it should be noted that this is merely one example of how the maximum length of wire is calculated.

[0062] Where:

[0063] Ix= Area moment of inertia m / L = Mass to length ratio

[0064] Ki = Coefficient for first beam mode = 22.4

[0065] D = Wire diameter (m)

[0066] E = Young’s Modulus (N / m2) m = Mass of copper (kg)

[0067] L = Length of wire flexure (m) p = Density of wire (kg / mm) FIG. 4 illustrates a graph indicating the varying of wire flexure 300 lengths versus their natural frequencies for the flowmeter’s 42-gauge copper transducer wire. The dashed line represents a drive frequency of 800 Hz, which is assumed to be the highest drive frequency encountered by the flowmeter 5, and is provided merely as a reference. Of course, it will be understood that this is merely an example and different wire, having different diameter, density, material, and other properties may be used. Furthermore, different highest drive frequencies will be understood based on the particular model / type of flowmeter. Additionally, different wire flexure 300 lengths will be encountered, and this will be based on the particular model / type of flowmeter.

[0068] It will be apparent in this example, that at a length of about 0.625 inches (-15.9 mm) or longer the natural frequencies of the flexures are at or lower than the indicated highest drive frequency. In this embodiment, the length of wire is thus chosen / cut such that it docs not have a natural frequency close to or lower than the sensor drive frequency, which results in a decreased likelihood of undesirable amplified vibration.

[0069] In order to verify these results, different wire lengths were tested, as shown in FIG. 5. This plot shows whether a specific length of wire flexure significantly vibrates at the drive frequency, which is 800Hz in this example. The Y-axis simply indicates whether vibrations are present (Yes or No). The flexure switches from not visibly vibrating to visibly vibrating between lengths 0.60 inches (~15.2mm) and 0.65 inches (~16.5mm), thus confirming the calculations used to generate the graph of FIG. 4 are representative of the wire flexures 300 and can be used to define design constraints. In embodiments, the sensor's 10 highest driving frequency constrains the maximum length of flexures.

[0070] It was determined that in embodiments where wire flexures having a flexure natural frequency ratio value greater than 0.8 are likely to vibrate at the driving frequency and should be avoided. Therefore, in embodiments, the wire flexure 300 preferably has a flexure natural frequency ratio value less than or equal to 0.8. f

[0071] Flexure natural frequency ratio =Drive(4) f Flex Where: Drive = Drive frequency (Hz) fpiex ~ Wire flexure natural frequency (Hz)

[0072] Typically, there is some slack in each wire flexure 300 between the PCB and the coil 107 (See FIG. 6) to allow for strain relief and to facilitate the assembly process. Extra length in the flexures creates a small curve or arc shape. In an embodiment, if a wire's parameters satisfy the ratio in Equation 5, the wire flexure 300 can be approximated as a straight wire, and the arc created is deemed negligible. In an embodiment, the slack in each flexure is between 0.625 and 0.25 inches (~1.6 to ~6.4mm). In an embodiment, there is about 0.125 inches (~3.2mm) of slack.

[0073] In an embodiment, a wire's parameters satisfy the ratio in Equation 5 if the ratio is greater than or equal to 4.5.

[0074] Where:

[0075] Lgap= gap length between the transducer coil (where the wire flexure 300 emanates from the coil) and the point of attachment of the wire flexure end h = height of flexure arc

[0076] These dimensions are illustrated by FIG. 6. In this illustration the wire flexure 300 is attached to a solder pad 303 of a printed circuit board (PCB) 302. Lgapwould typically be measured from the coil 107 to the wire flexure 300 point of attachment 307 on the solder pad 303. In some embodiments, the point of attachment may be mechanical instead of a solder joint.

[0077] If, however, the flexure does not satisfy the straight wire approximation ratio, being less than 4.5, then the wire flexure 300 should be considered as an arc shape.

[0078] In an embodiment, the orientation of the arc wire flexure 300 is considered. In embodiments, the orientation of the wire flexure 300 is horizontal. In embodiments, the orientation of the wire flexure 300 is vertical. In embodiments, the orientation of the wire flexure 300 is between horizontal and vertical. For the purpose of the embodiments provided, the vertical orientation is defined as when the arc height of the wire flexure 300 varies in the drive direction and curves up into the drive axis as in FIG. 7A and 7B. In the vertical orientation, the arc lies substantially within the meter’s 5 XY plane. Horizontal orientation is defined as when the arc is perpendicular to the drive direction and lays flat within the tube plane and has no height variation in the drive axis as in FIG. 8. In the horizontal orientation, the arc lies substantially within the meter’s 5 XZ plane.

[0079] Comparing the behavior of the two different arc orientation embodiments, wire flexure 300 arcs oriented in a horizontal orientation vibrate at the drive frequency at shorter lengths compared to when the same length flexure arcs are oriented in the vertical direction. In other words, horizontal arcs have lower excitable frequencies than vertical arcs. The flow conduits 103 A, 103B vibrate in the vertical axis, and when flexures are oriented horizontally, the bending modes of the flexure tend to be excited. Bending modes have lower frequencies than rolling modes that arc excited vertically. Therefore, it is preferable to have the arcs oriented in the vertical direction to increase the resonant frequencies of the flexure to be sufficiently higher than the drive frequency and thus prevent vibration. The horizontal orientation is useable, and may be necessary in certain flowmeter configurations, but as noted, the vertical orientation is preferred.

[0080] In another embodiment, a dampening compound 304 (See FIG. 6) is introduced to the wire flexure 300. In an embodiment, the dampening compound 304 comprises one of RTV (Room Temperature Vulcanizing) silicone, hot melt adhesives, epoxy, acrylic, polyurethane, or any other polymer / adhesive / potting known in the art. In an embodiment, the dampening compound 304 is placed onto the PCB 302 over the flexure wire proximate the connection therebetween. Besides some level of damping, the dampening compound 304 effectively shortens the effective length of the wire flexure 300.

[0081] By applying a dampening compound 304, the active length end point of the wire flexure 300 is effectively transferred proximate the edge of the PCB 302, rather than the center of the solder pad 303. Changing the endpoint location shortens the length of the flexure and in turn increases the natural frequency of the flexure. Larger amounts of dampening compound 304 also introduce a material that adds damping to the ends of the flexure, and increasing damping on the wire flexure 300 decreases the likelihood of vibration. 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.

[0082] Thus, although specific embodiments of, and examples for, the sensor assembly 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 sensor assemblies, 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

CLAIMSWe claim:

1. A sensor assembly (10) for a vibrating meter (5), comprising: one or more conduits (103 A, 103B); one or more sensor components including one or more of a driver (104), a first pick-off sensor (105), and a second pick-off sensor (105’) coupled to the one or more conduits (103 A, 103B), wherein the one or more sensor components each comprise a coil (107); and a wire flexure (300) extending from the coil (107) and electrically coupled to meter electronics (20); wherein the wire flexure (300) is configured to comprise a length (L) that confers a resonant frequency to the wire flexure (300) that is higher than the highest drive frequency of the sensor assembly (10).

2. The sensor assembly (10) of claim 1, wherein a flexure natural frequency ratio value is less than or equal to 0.8, wherein the flexure natural frequency ratio comprises the highest drive frequency of the sensor assembly (10) divided by a natural frequency of the wire flexure (300).

3. The sensor assembly (10) of claim 1, wherein a straight wire approximation ratio is greater than or equal to 4.5, wherein the straight wire approximation ratio comprises a gap length (Lgap) between the coil (107) where the wire flexure (300) emanates from the coil (107) and a point of attachment (307) of the wire flexure divided by a height (h) of the flexure arc.

4. The sensor assembly (10) of claim 1, wherein a dampening compound (304) is placed on the wire flexure (300) proximate a point of attachment (307) of the wire flexure end.

5. The sensor assembly (10) of claim 1, wherein the wire flexure (300) forms an arc between the coil (107) and a point of attachment (307) of the wire flexure (300), wherein the orientation of the wire flexure (300) is vertical, such that the arc’s curvature curves into a direction of the meter’s (5) drive axis and lies substantially within the flowmeter’s (5) XY plane.

6. The sensor assembly (10) of claim 1, wherein the wire flexure (300) forms an arc between the coil (107) and a point of attachment (307) of the wire flexure (300), wherein the orientation of the wire flexure (300) is horizontal, such that the arc’s curvature curves into a direction perpendicular to the meter’ s (5) drive axis and lies substantially within the flowmeter’s (5) XZ plane.

7. The sensor assembly (10) of claim 1, wherein the wire flexure (300) forms an arc between the coil (107) and a point of attachment (307) of the wire flexure (300), wherein the orientation of the wire flexure (300) is between horizontal and vertical.

8. The sensor assembly (10) of claim 1, wherein a straight wire approximation ratio is less than 4.5, wherein the straight wire approximation ratio comprises a gap length (Lgap) between the coil (107) where the wire flexure (300) emanates from the coil (107) and a point of attachment of the wire flexure end (307) divided by a height (h) of the flexure arc.

9. A method for configuring a sensor assembly for a vibrating meter, comprising: providing one or more conduits; providing one or more sensor components including one or more of a driver, a first pick-off sensor, and a second pick-off sensor coupled to the one or more conduits, wherein the one or more sensor components each comprise a coil; and extending a wire flexure from the coil to electrically couple the coil to meter electronics; configuring the wire flexure to comprise a length (L) that confers a resonant frequency to the wire flexure that is higher than the highest drive frequency of the sensor assembly.

10. The method of claim 9, wherein a flexure natural frequency ratio value is less than or equal to 0.8, wherein the flexure natural frequency ratio comprises the highest drive frequency of the sensor assembly divided by a natural frequency of the wire flexure.

11. The method of claim 9, wherein a straight wire approximation ratio is greater than or equal to 4.5, wherein the straight wire approximation ratio comprises a gap length (Lgap) between the coil where the wire flexure emanates from the coil and a point of attachment of the wire flexure divided by a height (h) of the flexure arc.

12. The method of claim 9, comprising placing a dampening compound on the wire flexure proximate a point of attachment of the wire flexure end.

13. The method of claim 9, comprising: forming an arc with the wire flexure between the coil and a point of attachment of the wire flexure; orienting the wire flexure vertically, such that the arc’s curvature curves into a direction of the meter’s drive axis and lies substantially within the flowmeter’s XY plane.

14. The method of claim 9, comprising: forming an arc with the wire flexure between the coil and a point of attachment of the wire flexure; orienting the wire flexure horizontally, such that the arc’s curvature curves into a direction perpendicular to the meter’s drive axis and lies substantially within the flowmeter’s XZ plane.

15. The method of claim 9, comprising forming an arc between the coil and a point of attachment of the wire flexure, wherein the orientation of the wire flexure is between horizontal and vertical.

16. The method of claim 9, wherein a straight wire approximation ratio is less than 4.5, wherein the straight wire approximation ratio comprises a gap length (Lgap) between the coil where the wire flexure emanates from the coil and a point of attachment of the wire flexure end divided by a height (h) of the flexure arc.

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