HK1170298B - A flow meter including a balanced reference member - Google Patents

Description

Flow meter including a balanced reference member

Technical Field

The present invention relates to a vibratory flow meter, and more particularly to a vibratory flow meter including a balanced reference member.

Background

Vibrating flow devices, such as densitometers and coriolis flowmeters, are used to measure characteristics of a flow material, such as density, mass flow rate, volumetric flow rate, total mass flow, temperature, and other information. The vibrating flow device includes one or more conduits that may have a variety of shapes, such as straight, U-shaped, or irregular configurations.

One or more conduits have a set of natural vibration modes including, for example, simple bending, torsional, radial, and coupled modes. At least one driver vibrates one or more conduits at a resonant frequency in one or more of the drive modes in order to determine a characteristic of the flow material. The one or more meter electronics transmit the sinusoidal drive signal to at least one driver, which is typically a magnet/coil combination, the magnet typically being fixed to the conduit and the coil being fixed to the mounting structure or another conduit. The drive signal causes the driver to vibrate the one or more conduits at a drive frequency in the drive mode. For example, the drive signal may be a periodic current delivered to the coil.

At least one sensor detects motion of the conduit(s) and generates a sinusoidal sensor signal representative of the motion of the vibrating conduit(s). The sensor is typically a magnet/coil combination, the magnet typically being secured to one catheter and the coil being secured to a mounting structure or another catheter. However, it should be appreciated that other sensor arrangements exist, such as optical, capacitive, piezoelectric, and the like. The sensor signal is communicated to one or more electronics and, in accordance with well-known principles, may be used by one or more meter electronics to determine a characteristic of the flowing material or to adjust the drive signal if necessary.

Typically, vibrating flow devices are provided with two vibrating conduits that vibrate opposite to each other to create a system that is inherently balanced. As a result, the vibrations from each conduit balance each other so that undesired vibrations from one conduit are prevented from passing to the other conduit. However, there are applications where the use of dual catheters is undesirable, for example due to problems with pressure drop or clogging. In such a case, a single catheter system may be desirable.

An imbalance is created in a single conduit system because the sensor measures motion by determining the relative position between a first sensor component located on the reference member and a second sensor component located on the conduit. Thus, undesired vibrations transmitted to the reference member may cause components of the sensor located on the reference member to vibrate or move in an undesired manner. This in turn may affect the relative position of the sensed sensor components, resulting in inaccurate sensor signals. Further, in some systems, the reference member is designed to vibrate in opposition to the flow conduit. However, if the density of the fluid flowing through the conduit changes, the reference member may not be able to oppose the vibration of the flow conduit.

Attempts to solve this problem have involved using dummy tube mounting structures attached to the conduit via struts, and using the motion of the dummy tubes to balance the system. While this approach may be adequate to some extent in some cases, it is often difficult to balance the system over a wide range of fluid densities, thereby limiting the effectiveness of existing approaches.

The present invention overcomes these and other problems and achieves a technical advance.

Disclosure of Invention

According to one embodiment of the present invention, a flow meter is provided. The flow meter includes a conduit and a driver configured to vibrate the conduit. According to an embodiment of the invention, the flow meter further comprises a first sensor. The first sensor includes a first sensor component and a second sensor component. The vibratory flow meter also includes a reference member. The first sensor component is coupled to the reference member and the second sensor component is coupled to the conduit adjacent the first sensor component. The vibratory flow meter also includes a balance element coupled to the reference member.

According to another embodiment of the invention, a reference member for a flow meter is provided. The reference member may include a movable portion. According to an embodiment of the invention, the movable part is adapted to vibrate around a bending axis W-W. According to an embodiment of the invention, the reference member further comprises a balancing element coupled to the reference member. The balancing element may be adapted to oscillate about the bending axis substantially opposite to the movable part.

In accordance with another embodiment of the present invention, a method is provided for forming a flow meter including a flow conduit, a driver, and a first sensor including a first sensor component and a second sensor component. The method comprises the following steps: a reference member is positioned adjacent the flow conduit and a first sensor component is coupled to the reference component. According to an embodiment of the invention, the method further comprises the step of: a second sensor component is coupled to the flow conduit adjacent the first sensor component. According to another embodiment of the invention, the method further comprises the steps of: coupling the balancing element to the reference member.

Aspect(s)

According to one aspect of the invention, a flow meter comprises:

a flow conduit;

a driver configured to vibrate the conduit;

a first sensor comprising a first sensor component and a second sensor component;

a reference member, wherein the first sensor component is coupled to the reference member and the second sensor component is coupled to the conduit adjacent the first sensor component; and

a balancing element coupled to the reference member.

Preferably, the reference member further comprises one or more legs at least partially defining a bending axis of the reference member.

Preferably, the balancing element is coupled to a movable portion of the reference member.

Preferably, the balancing element is sized and positioned such that the momentum of the balancing element is substantially equal and opposite to the momentum of the movable portion of the reference member.

Preferably, the balancing element is sized and positioned such that movement of the balancing element about the bending axis W-W of the reference member is substantially opposite to movement of the movable portion of the reference member.

Preferably, the flow meter further comprises at least a second sensor comprising a first sensor component coupled to the reference member and a second sensor component coupled to the conduit.

Preferably, the driver comprises a first component coupled to the reference member and a second component coupled to the conduit.

Preferably, the balancing element is integrally formed with the reference member.

Preferably, the balancing element is removably coupled to the reference member.

Preferably, the reference member comprises a reference plate.

In accordance with another aspect of the invention, a reference member for a flow meter comprises:

a movable portion adapted to vibrate about a bending axis; and

a balancing element coupled to the reference member and adapted to vibrate about the bending axis substantially opposite the active portion.

Preferably, the reference member further comprises one or more legs at least partially defining the bending axis.

Preferably, the balancing element is sized and positioned such that the momentum of the balancing element is substantially equal and opposite to the momentum of the movable portion.

Preferably, the balancing element is coupled to the movable portion of the reference member.

Preferably, the reference member comprises a reference plate.

In accordance with another aspect of the invention, a method for forming a flow meter including a flow conduit, a driver, and a first sensor including a first sensor component and a second sensor component, the method comprises the steps of:

positioning a reference member adjacent to the flow conduit;

coupling the first sensor component to the reference component;

coupling the second sensor component to the flow conduit adjacent the first sensor component; and

coupling a balancing element to the reference member.

Preferably, the step of coupling the balancing element to a reference member comprises coupling the balancing element to a movable portion of the reference member.

Preferably, the method further comprises the step of: the balancing element is sized and positioned such that a momentum of the balancing element is substantially equal and opposite to a momentum of the movable portion of the reference member.

Preferably, the method further comprises the step of: the balancing element is sized and positioned such that movement of the balancing element about the bending axis of the reference member is substantially opposite to movement of the movable portion of the reference member about the bending axis.

Preferably, the method further comprises the step of: coupling a first sensor component of at least a second sensor to the reference member and a second sensor component of the at least a second sensor to the flow conduit.

Preferably, the method further comprises the step of: coupling a first driver component to the reference member and a second driver component to the catheter.

Preferably, the reference member comprises a reference plate.

Drawings

Fig. 1 shows a perspective view of a prior art dual conduit vibratory flow device.

FIG. 2 shows a perspective view of a prior art single catheter sensor assembly.

FIG. 3 shows a perspective view of a prior art single catheter sensor assembly.

FIG. 4 illustrates a perspective view of an embodiment of a single catheter sensor assembly.

Detailed Description

Fig. 1-4 and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of the invention. 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 invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the invention. As a result, the invention is not limited to the specific examples described below, but only by the claims and their equivalents.

Fig. 1 shows an example of a prior art vibrating sensor assembly 5 in the form of a coriolis flow meter that includes a flow meter 10 and one or more meter electronics 20. One or more meter electronics 20 are connected to the flow meter 10 to measure characteristics of the flow material, such as density, mass flow rate, volume flow rate, total mass flow, temperature, and other information.

The flowmeter 10 includes a pair of flanges 101 and 101 ', manifolds 102 and 102', and conduits 103A and 103B. Manifolds 102, 102' are secured to opposite ends of conduits 103A, 103B. The flanges 101 and 101 'of the present example are secured to manifolds 102 and 102'. Manifolds 102 and 102' of the present example are secured to opposite ends of spacer 106. Spacers 106 maintain the spacing between manifolds 102 and 102' in this example to prevent undesirable vibration in conduits 103A and 103B. The conduits extend outwardly from the manifold in a substantially parallel manner. When the flowmeter 10 is inserted into a pipeline system (not shown) that carries flow material, the material enters the flowmeter 10 through the flange 101, passes through the inlet manifold 102 (where the entire amount of material is directed into conduits 103A and 103B), flows through conduits 103A and 103B and back to the outlet manifold 102 '(where it exits the flowmeter 10 through the flange 101').

The flow meter 10 includes a driver 104. The driver 104 is fixed to the conduits 103A, 103B at a position where the driver 104 is able to vibrate the conduits 103A, 103B in a driving mode. More specifically, the driver 104 includes a first driver component (not shown) secured to the catheter 103A and a second driver component (not shown) secured to the catheter 103B. Driver 104 may comprise one of many well-known arrangements, such as a magnet mounted to conduit 103A and an opposing coil mounted to conduit 103B.

In this example, the drive mode is the first out-of-phase bending mode, and conduits 103A and 103B are preferably selected and appropriately mounted to inlet and outlet manifolds 102 and 102 ' to provide a balanced system having substantially the same mass distribution, moment of inertia, and modulus of elasticity about bending axes W-W and W ' -W ', respectively. In the present example, where the drive mode is the first out of phase bending mode, conduits 103A and 103B are driven in opposite directions about their respective bending axes W and W' by driver 104. The one or more meter electronics 20 may provide a drive signal in the form of an alternating current, for example, via the channel 110, which passes through the coil to cause the two conduits 103A, 103B to vibrate. Those of ordinary skill in the art will recognize that other drive modes may be used within the scope of the present invention.

The balance system causes the flow conduits 103A, 103B to oscillate generally in the Z direction as shown. Other directions include the X-direction along the pipeline and the Y-direction perpendicular to the Z-direction and the X-direction. This coordinate system is used for all parts of the present application and may assist in understanding the present invention. It should be appreciated that other coordinate systems may be used, and the particular coordinate system used should not limit the scope of the invention.

The illustrated flow meter 10 includes a pair of transducers 105, 105' secured to conduits 103A, 103B. More specifically, a first sensor component (not shown) is located on conduit 103A, and a second sensor component (not shown) is located on conduit 103B. In the illustrated embodiment, the sensors 105, 105' are located at opposite ends of the conduits 103A, 103B. The sensors 105, 105' may be electromagnetic detectors, such as sensor magnets and sensor coils, that produce sensor signals representative of the velocity and position of the catheters 103A, 103B. For example, the sensors 105, 105 'may supply sensor signals to one or more meter electronics 20 via channels 111, 111'. Those skilled in the art will appreciate that the motion of the conduits 103A, 103B is proportional to certain characteristics of the flowing material, such as the mass flow rate and density of the material flowing through the conduits 103A, 103B.

In the example shown in fig. 1, one or more meter electronics 20 receive sensor signals from sensors 105, 105'. Path 26 provides input and output means that allow one or more meter electronics 20 to interact with an operator. One or more meter electronics 20 measure characteristics of the flowing material, such as density, mass flow rate, volume flow rate, total mass flow, temperature, and other information. More specifically, one or more meter electronics 20 receive one or more signals, for example, from sensors 105, 105' and one or more temperature sensors (not shown), and use this information to measure characteristics of the flowing material, such as density, mass flow rate, volume flow rate, total mass flow, temperature, and other information.

Techniques for measuring properties of a flow material with a vibratory measuring device (e.g., a coriolis flow meter or a densitometer) are well known, see, for example, U.S. patent No.6,505,131, the disclosure of which is incorporated herein by reference, and therefore, a detailed discussion is omitted for the sake of brevity of this description.

Turning now to fig. 2 and 3, another example of a prior art flow meter is shown at reference numeral 110. The flow meter 110 is similar to the flow meter 10 shown in fig. 1, except that the flow meter 110 includes a single conduit 103A and a reference member 150, with the transducers 105, 105' and a portion of the driver 104 being mounted on the reference member 150. In the example shown, the conduit 103A and the reference member 150 are not directly connected together. However, the positioning of the reference member 150 adjacent to the flow conduit 103A allows the first and second components of the sensors 105, 105' and the driver 104 to interact with each other, as is generally known in the art. The specific distance between the reference member 150 and the flow conduit 103A may depend on a number of considerations, including but not limited to the size of the flow conduit 103A, the size of the driver 104 and sensors 105, 105', and the mounting structure to which the flow meter 110 is mounted. Thus, it should be appreciated that the specific distance between the reference member 150 and the flow conduit 103A may vary from one flow meter to another.

According to another aspect of this embodiment, unlike flow tubes, the reference member 150 can be a structure through which material does not flow, such as a reference plate as shown or any other structure, regardless of shape. Thus, although the reference member 150 is shown to include a reference plate, the present invention should not be limited to plates, but rather, the reference member 150 may include any desired shape. It should be appreciated that, although not shown, the reference member 150 may be substantially rigidly coupled to the stationary component. For the purpose of reducing the complexity of the drawing, the installation of the reference member 150 is not shown in the drawing, nor is the installation of the flow conduit 103A in-line. In addition, the meter electronics 20 has been omitted from FIGS. 2-4 to simplify the complexity of the drawings. However, it should be appreciated that in practice, the flow meters 110 and 210 will be connected to the meter electronics in a manner similar to that described with reference to FIG. 1.

As shown, the first driver component 104a and the first sensor components 105a, 105 a' are coupled to the reference member 150. As shown, the second driver component 104b and the second sensor components 105b, 105 b' are coupled to the conduit 103A. The first part 104a, 105a 'may be a coil and the second part 104b, 105 b' may be a magnet. Alternatively, the first part 104a, 105a 'may be a magnet and the second part 104b, 105 b' may be a coil. Other configurations are also possible, such as optical sensors, capacitive sensors, or piezoelectric sensors. Thus, the present invention should not be limited to magnet/coil sensors.

In this example, the first and second driver components 104a, 104b of the driver 104 force the conduit 103A to oscillate about the bending axis W '-W'. In the example shown in fig. 2 and 3, as the driver 104 vibrates the conduit 103A about the axis W ' -W ', the driver 104 can excite the reference member 150 and cause movement of the first sensor components 105a, 105a ' even though the reference member 150 is not directly connected to the conduit 103A. In other words, the driver 104 may cause the movable portion 151 of the reference member 150 to vibrate about the bending axis W-W, similar to the manner in which the tube 103B vibrates in fig. 1, while the substantially stationary portion 152 does not vibrate or at least does not vibrate to the extent of the movable portion 151. The location of the reference member bending axis W-W may be determined based at least in part on the shape and stiffness of the reference member 150. According to the reference member 150 shown in fig. 3 and 4, the bending axis W-W is at least partially defined by one or more legs 160, 160'. Although two legs 160, 160' are shown, it should be appreciated that the reference member 150 may include only one leg or may include more than two legs. Accordingly, the particular number of legs 160, 160' provided should not limit the scope of the present invention.

Unlike the system of FIG. 1, in which vibration of the flow tube 103B about the bending axis W-W is desired, movement of the movable portion 151 of the reference member 150 about the axis W-W is generally considered undesirable. This is because in the illustrated embodiment, the first components 104a, 105 a' of the driver and sensor are coupled to the active portion 151 of the reference member 150, so that movement of the active portion 151 of the reference member 150 can be considered movement caused by fluid flowing through the conduit, thereby resulting in erroneous measurements. It should be appreciated, however, that even if the first components 104a, 105 a' of the driver and sensor are coupled to the stationary portion 152 of the reference member 150, vibrations generated by the movable portion 151 are still experienced, resulting in measurement errors. Another problem is that vibrations external to the sensor assembly 110 (e.g., vibrations generated by a pump or valve) may also be transmitted to the reference member 150. Such undesired vibrations may impart undesired motion to the first sensor components 105a, 105a ', thereby negatively affecting the accuracy of the sensor signals from the sensors 105, 105'.

While attempts to limit the movement of the reference member 150 have reduced the movement of the movable portion 151 of the reference member 150, some movement is still typically experienced. This is particularly true when the fluid density of the fluid flowing through the flow conduit 103A varies. Changes in fluid density can affect the magnitude of the vibration and require greater or lesser driving forces, resulting in changes in the force experienced by the reference member 150.

Fig. 4 shows a flow meter system 210 according to an embodiment of the invention. As shown, the flow meter 210 is similar to the flow meter 110 shown in fig. 2 and 3, except that the reference member 150 includes at least one balance element 253. According to an embodiment of the present invention, the balancing element 253 comprises a portion of the reference member 150 that provides a means for balancing the vibrations transmitted to the reference member 150. According to an embodiment of the invention, a balancing element 253 may be located between the legs 160, 160', which at least partially defines the bending axis W-W of the reference member 150. According to an embodiment of the invention, the balancing element 253 may be coupled to the movable portion 151 of the reference member 150. However, it should be appreciated that in other embodiments, the balancing element 253 may be coupled to another portion of the reference member 150, such as the inactive portion 152 or one of the legs 160, 160'.

Advantageously, the balancing element 253 can be sized and positioned on the reference member 150 such that the vibration of the reference member 150 about the bending axis W-W is substantially opposite the vibration of the balancing element 253. According to some embodiments, the balancing element 253 may be sized and positioned such that a momentum of the balancing element 253 is substantially equal and opposite to a momentum of the active portion of the reference member 150 about the bending axis W-W. In other words, using the provided coordinate system, the balance member 253 disposed on the opposite side of the bending axis W-W moves in the + Z, + Y direction as the movable portion 151 attempts to move in the-Z, -Y direction away from the flow conduit 103A. Accordingly, the movement of the movable portion 151 of the reference member 150 may be substantially resisted. Accordingly, the balancing element 253 may be sized and positioned such that the mass times the velocity (momentum) of the balancing element 253 about the axis W-W is substantially equal to the mass times the velocity of the movable portion 151 of the reference member 150, thereby creating substantially equal and opposite momentums. In other embodiments, the balancing element 253 can be sized and positioned such that the momentum of the balancing element 253 is substantially opposite to the momentum of the active portion 151 of the reference member 150 and greater than the momentum of the active portion 151 of the reference member 150. This can further restrict the movement of the movable portion 151.

In some embodiments, the stiffness and mass of the balancing element 253 may be selected such that the natural frequency of the balancing element 253 is lower than the driving frequency. As a result, the balance element 253 tends to move out of phase with the movement of the movable portion 151 of the reference member 150. Thus, the vibration of the reference member 150 is minimized, thereby minimizing the motion of the first parts 104a, 105 a' of the driver and sensor.

According to embodiments of the invention, the balancing element 253 may be sized and positioned on the reference member 150 such that the balancing element 253 moves opposite the reference member 150, and more specifically, opposite the movable portion 151 of the reference member 150. For example, as described above, in some embodiments, as flow conduit 103A is driven by driver 104, driver 104 will also excite reference member 150, causing reference member 150 to vibrate about axis W-W. While it is desirable to form a stationary reference member 150 that does not vibrate, such attempts have proven difficult and variable depending on the flowmeter mounting conditions. However, the balancing element 253 may be arranged such that vibrations of the reference member 150 about the axis W-W are opposed by the balancing element 253. Thus, the movement of the reference member 150 in the area of the first driver and sensor components 104a, 105 a' may be minimized. This is because as the top portion (movable portion 151) of the reference member 150 (where the first driver and sensor parts 104a, 105 a') move in a first direction, such as the-Z, -Y direction, the balance element 253 moves in a second direction, such as the + Z, + Y direction, which is opposite to the first direction. Thus, the movement of the reference member 150 not only requires sufficient force to overcome the stiffness of the reference member 150, but also sufficient force to overcome the opposing force of the balancing element 253.

One skilled in the art will appreciate that the balancing element 253 can be adjusted by determining an appropriate material, location, shape, length, width, thickness, mass, and/or other characteristic to balance the vibrations imparted to the reference member 150. Those skilled in the art will appreciate that in practice, flow meters are typically not identical to each other. For example, and without limitation, flow meters typically differ at least to some extent in their mass, their mass distribution, the vibration amplitudes and/or frequencies involved, and the particular material flowing through the conduit or the density of the particular material. One of ordinary skill in the art will appreciate that even small differences in mass, mass distribution, vibration amplitude and/or frequency, and the particular material flowing through the conduit or the density of the particular material, may affect the material, location, shape, length, width, thickness, mass, and/or other characteristics of the balancing element 253. Accordingly, one of ordinary skill in the art will appreciate that certain routine testing may be required in order to determine the appropriate material, location, shape, length, width, thickness, mass, and/or other characteristics of the balancing element 253. For example, a particular balancing element 253 may be sized and positioned to accommodate a range of fluid densities. The fluid density range may be selected based on the density of the desired fluid. If fluids having different densities are measured, the balancing element 253 can be replaced with a balancing element 253 of an appropriate size to accommodate the new fluid density.

One of ordinary skill in the art will appreciate that more than one balancing element 253 may be used within the scope of the present invention. Further, in this case, the balancing elements 253 may have different shapes, lengths, widths, thicknesses and/or masses. One of ordinary skill in the art will appreciate that the balancing element 253 may be integrally formed with the reference member 150 as shown. Alternatively, the balancing element 253 may be a separate structure that is connected to the reference member 150, for example and without limitation, removably connected to the reference member 150. Further, while the driver 104 may include a first driver component 104a connected to the reference member 150 and a second driver component 104b connected to the conduit 103A, as shown, one of ordinary skill in the art will appreciate that in alternative embodiments, the driver 104 may be a device (e.g., without limitation, a piezoelectric device) connected to the conduit 103A but not connected to the reference member 150.

It will be appreciated by those skilled in the art that it is within the scope of the present invention to use the principles discussed herein in conjunction with any type of vibrating flow device, including, for example, coriolis flowmeters, densitometers, regardless of the number of drives, the number of sensors, the mode of operation of the vibration, or the determined characteristics of the flow material. Furthermore, while the above description has been limited to single tube flowmeters, it is certainly within the scope of the invention to include the features of the present invention in a dual flow tube flowmeter. For example, the reference member 150 may be disposed between the flow tubes 103A, 103B. Additionally, while the illustrated embodiment shows a flow meter having curved or U-shaped flow conduits, it should be appreciated that the present invention is equally applicable to straight tube flow meters or flow meters having irregular flow tubes. This written description depicts specific examples to teach those skilled in the art how to make and use the best mode of the invention. 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 invention.

The above detailed description of embodiments is not an exclusive description of all embodiments within the scope of the invention as contemplated by the inventors. Indeed, those skilled in the art will recognize that certain elements of the above-described embodiments may be combined or eliminated in various ways to produce other embodiments, and that such other embodiments fall within the scope and teachings of the invention. 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 other embodiments within the scope and teachings of the invention.

Thus, while specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. The teachings provided herein can be applied to other flow meters, not just the embodiments described above and shown in the figures. The scope of the invention should, therefore, be determined with reference to the appended claims.

Claims (19)

1. A flow meter (210), comprising:

a flow conduit (103A);

a driver (104) configured to vibrate the catheter (103A);

a first sensor (105) comprising a first sensor component (105 a) and a second sensor component (105 b);

a reference member (150), wherein the first sensor component (105 a) is coupled to the reference member (150) and the second sensor component (105 b) is coupled to the conduit (103A) adjacent the first sensor component (105 a); and

a balancing element (253) coupled to the reference member (150), wherein the balancing element (253) is sized and positioned such that a momentum of the balancing element (253) is substantially equal and opposite to a momentum of the active portion (151) of the reference member (150).

2. The flow meter (210) of claim 1, wherein the reference member (150) further comprises one or more legs (160, 160 '), the one or more legs (160, 160') at least partially defining a bending axis (W-W) of the reference member (150).

3. The flow meter (210) of claim 1, wherein the balance element (253) is coupled to the active portion (151) of the reference member (150).

4. The flow meter (210) of claim 1, wherein the balance element (253) is sized and positioned such that movement of the balance element (253) about a bending axis (W-W) of the reference member (150) is substantially opposite to movement of the movable portion (151) of the reference member (150).

5. The flow meter (210) of claim 1, further comprising at least a second sensor (105 ') including a first sensor component (105 a ') coupled to the reference member (150) and a second sensor component (105 b ') coupled to the conduit (103A).

6. The flow meter (210) of claim 1, wherein the driver (104) includes a first component (104 a) coupled to the reference member (150) and a second component (104 b) coupled to the conduit (103A).

7. The flow meter (210) of claim 1, wherein the balance element (253) is integrally formed with the reference member (150).

8. The flow meter (210) of claim 1, wherein the balance element (253) is removably coupled to the reference member (150).

9. The flow meter (210) of claim 1, wherein the reference member (150) comprises a reference plate.

10. A reference member (150) for a flow meter (210), comprising:

a movable portion (151) adapted to vibrate about a bending axis (W-W); and

a balancing element (253) coupled to the reference member (150) and adapted to vibrate about the bending axis (W-W) substantially opposite to the active portion (151), wherein the balancing element (253) is sized and positioned such that a momentum of the balancing element (253) is substantially equal and opposite to a momentum of the active portion (151).

11. The reference member (150) of claim 10, further comprising one or more legs (160, 160 '), the one or more legs (160, 160') at least partially defining the bending axis (W-W).

12. The reference member (150) of claim 10, wherein the balancing element (253) is coupled to the active portion (151) of the reference member (150).

13. The reference member (150) of claim 10, wherein the reference member (150) comprises a reference plate.

14. A method for forming a flow meter comprising a flow conduit, a driver, and a first sensor comprising a first sensor component and a second sensor component, the method comprising the steps of:

positioning a reference member adjacent to the flow conduit;

coupling the first sensor component to the reference component;

coupling the second sensor component to the flow conduit adjacent the first sensor component;

coupling a balancing element to the reference member; and

the balancing element is sized and positioned such that a momentum of the balancing element is substantially opposite and equal to or greater than a momentum of the active portion of the reference member.

15. The method of claim 14, wherein the step of coupling a balancing element to a reference member includes coupling the balancing element to the active portion of the reference member.

16. The method of claim 14, further comprising the step of: sizing and positioning the balancing element such that movement of the balancing element about a bending axis of the reference member is substantially opposite to movement of the movable portion of the reference member about the bending axis.

17. The method of claim 14, further comprising the step of: coupling a first sensor component of at least a second sensor to the reference member and a second sensor component of the at least a second sensor to the flow conduit.

18. The method of claim 14, further comprising the step of: coupling a first driver component (104A) of the driver (104) to the reference member (150) and a second driver component (104B) of the driver (104) to the flow conduit (103A).

19. The method of claim 14, wherein the reference member comprises a reference plate.