Abstract:
An apparatus ( 400 ) for a vibratory meter ( 100 ) having one or more flow tubes ( 101, 102 ) adapted to vibrate is provided. The apparatus ( 400 ) comprising two or more brace bars ( 203, 204 ) adapted to couple to the one or more flow tubes ( 101, 102 ), and an isolation bar ( 402 ) coupled to the two or more brace bars ( 203, 204 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a vibratory meter, and more particularly, to a method and apparatus for a vibratory meter. 
     2. Statement of the Problem 
     Vibrating conduit sensors, such as Coriolis mass flow meters and vibrating densitometers, typically operate by detecting motion of a vibrating conduit that contains a material. Properties associated with the material in the conduit, such as mass flow, density and the like, can be determined by processing measurement signals received from motion transducers associated with the conduit. The vibration modes of the vibrating material-filled system generally are affected by the combined mass, stiffness and damping characteristics of the containing conduit and the material contained therein. 
     A typical Coriolis mass flow meter includes one or more conduits that are connected inline in a pipeline or other transport system and convey material, e.g., fluids, slurries, emulsions, and the like, in the system. Each conduit may be viewed as having a set of natural vibration modes, including for example, simple bending, torsional, radial, and coupled modes. In a typical Coriolis mass flow measurement application, a conduit is excited in one or more vibration modes as a material flows through the conduit, and motion of the conduit is measured at points spaced along the conduit. Excitation is typically provided by an actuator, e.g., an electromechanical device, such as a voice coil-type driver, that perturbs the conduit in a periodic fashion. Mass flow rate may be determined by measuring time delay or phase differences between motions at the transducer locations. Two such transducers (or pickoff sensors) are typically employed in order to measure a vibrational response of the flow conduit or conduits, and are typically located at positions upstream and downstream of the actuator. The two pickoff sensors are connected to electronic instrumentation. The instrumentation receives signals from the two pickoff sensors and processes the signals in order to derive a mass flow rate measurement, among other things. Vibratory meters, including Coriolis mass flow meters and densitometers, therefore employ one or more flow tubes that are vibrated in order to measure a fluid. 
     The techniques by which the vibrating Coriolis flow meters, measure parameters of a flowing material are well understood; see, for example, U.S. Pat. No. 6,505,131, the disclosure of which is hereby incorporated herein by reference; therefore, a detailed discussion is omitted for brevity of this description. 
     In vibrating Coriolis flow meters, the amplitude of the Coriolis deflections is considerably less than the amplitude of the flow tube drive frequency vibrations. Even though the amplitude of the Coriolis deflections is relatively small, it is the Coriolis deflections in the flow tube vibrations that generate the pick-off output signals that are processed by meter electronics to determine the mass flow rate and other parameters of the flowing material. Many vibrating Coriolis flow meters that generate pick off output signals from Coriolis deflections are capable of obtaining an output error of about 0.15% or less. However, in order to achieve this accuracy, interference of the Coriolis deflections are minimized. Although the above discussion addresses deflections in Coriolis flow meters, it should be understood that the deflections in other vibratory meters may be employed to measure parameters of the flowing material. 
     Vibratory meters are sometimes connected to other equipment that vibrates. For example, the pipelines the vibratory meters are connected to may be part of some equipment (e.g., semiconductor equipment, etc.). The equipment may have moving parts such as motors and pumps. These moving parts may impart a vibration to the equipment which in turn vibrates the pipelines connected to the vibratory meters. Moreover, the vibrations from the equipment may be imparted to the vibratory meters through means other than the manifold. For example, the vibratory meters may mount directly to the vibrating equipment which couples undesirable vibration to the flow tubes. Accordingly, the undesirable vibration in the pipelines or other parts of the equipment may transfer to the one or more flow tubes in the vibratory meter. 
     These undesirable vibrations may interfere with the Coriolis deflections which are used to measure the parameters of the material flowing through the flow tubes. This interference may increase the output error of the measurements of the flowing material. Increasing the output error in measurements of material is typically undesirable. Hence, there is a need to isolate a vibratory meter. 
     Aspects of the Invention 
     In one aspect of the invention, an apparatus ( 400 ) for a vibratory meter ( 100 ) having one or more flow tubes ( 101 ,  102 ) adapted to vibrate, comprising: 
     two or more brace bars ( 203 ,  204 ) adapted to couple to the one or more flow tubes ( 101 ,  102 ); 
     and an isolation bar ( 402 ) coupled to the two or more brace bars ( 203 ,  204 ). 
     Preferably, the two or more brace bars ( 203 ,  204 ) are coupled to the one or more flow tubes ( 101 ,  102 ). 
     Preferably, the isolation bar ( 402 ) includes an aperture ( 806   a ). 
     Preferably, the isolation bar ( 402 ) is adapted to isolate the vibratory meter ( 100 ). 
     Preferably, the one or more parameters of the isolation bar ( 402 ) are selected to isolate the vibratory meter ( 100 ). 
     Preferably, the one or more parameters selected includes a dimension of the isolation bar ( 402 ) selected to isolate the vibratory meter ( 100 ). 
     Preferably, the dimension of the isolation bar ( 402 ) selected to isolate the vibratory meter ( 100 ) is the width of the isolation bar ( 402 ). 
     Preferably, the dimension of the isolation bar ( 402 ) selected to isolate the vibratory meter ( 100 ) is a dimension of an aperture ( 806   a ) in the isolation bar ( 402 ). 
     Preferably, the isolation bar ( 402 ) is positioned to isolate the vibratory meter ( 100 ). 
     Preferably, the isolation bar ( 402 ) is adapted to isolate the one or more flow tubes ( 101 ,  102 ). 
     Preferably, the isolation bar ( 402 ) comprises a flat plate adapted to isolate the vibratory meter ( 100 ). 
     Preferably, the apparatus further comprises a second isolation bar ( 502 ) coupled to the two or more brace bars ( 203 ,  204 ). 
     In another aspect of the present invention, a method for a vibratory meter ( 100 ) having one or more flow tubes ( 101 ,  102 ) adapted to vibrate, comprising: 
     forming two or more brace bars ( 203 ,  204 ) adapted to couple to the one or more flow tubes ( 101 ,  102 ); and 
     forming and coupling an isolation bar ( 402 ) to the two or more brace bars ( 203 ,  204 ). 
     Preferably, the method further includes coupling the two or more brace bars ( 203 ,  204 ) to the one or more flow tubes ( 101 ,  102 ). 
     Preferably, forming and coupling the isolation bar ( 402 ) to the one or more brace bars ( 203 ,  204 ) includes forming an aperture ( 806   a ) in the isolation bar ( 402 ). 
     Preferably, forming and coupling the isolation bar ( 402 ) to the two or more brace bars ( 203 ,  204 ) includes adapting the isolation bar ( 402 ) to isolate the vibratory meter ( 100 ). 
     Preferably, the forming and coupling the isolation bar ( 402 ) to the two or more brace bars ( 203 ,  204 ) includes selecting one or more parameters of the isolation bar ( 402 ) to isolate the vibratory meter ( 100 ). 
     Preferably, the selecting the one or more parameters of the isolation bar ( 402 ) includes selecting a dimension of the isolation bar ( 402 ). 
     Preferably, the selecting the dimension of the isolation bar ( 402 ) to isolate the vibratory meter ( 100 ) comprises selecting a width of the isolation bar ( 402 ). 
     Preferably, the selecting the dimension of the isolation bar ( 402 ) to isolate the vibratory meter ( 100 ) comprises selecting a dimension of an aperture ( 806   a ) in the isolation bar ( 402 ). 
     Preferably, the forming and coupling the isolation bar ( 402 ) includes positioning the isolation bar ( 402 ) to isolate the vibratory meter ( 100 ). 
     Preferably, the forming and coupling the isolation bar ( 402 ) to the two or more brace bars ( 203 ,  204 ) includes isolating the one or more flow tubes ( 101 ,  102 ). 
     Preferably, the forming and coupling the isolation bar ( 402 ) to the two or more brace bars ( 203 ,  204 ) includes isolating the vibratory meter ( 100 ). 
     Preferably, the method further includes forming and coupling a second isolation bar ( 502 ) to the two or more brace bars ( 203 ,  204 ). 
     In another aspect of the invention, a vibratory meter ( 100 ) having one or more flow tubes ( 101 ,  102 ), comprising: 
     two or more brace bars ( 203 ,  204 ) coupled to the one or more flow tubes ( 101 ,  102 ); and 
     an isolation bar ( 402 ) coupled to the two or more brace bars ( 203 ,  204 ). 
     Preferably, the isolation bar ( 402 ) is adapted to isolate the vibratory meter ( 100 ). 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a typical vibratory meter  100 . 
         FIG. 2  shows a cut away view of the vibratory meter  100 . 
         FIG. 3  shows a detailed isometric cut away view of the vibratory meter  100  at the inlet portion depicting an upper brace bar  302 . 
         FIG. 4  shows a first apparatus  400  for the vibratory meter  100  provided in accordance with an embodiment of the invention. 
         FIG. 5  shows a second apparatus  500  for the vibratory meter  100  provided in accordance with the present invention. 
         FIG. 6  shows a third apparatus  600  for the vibratory meter  100  provided in accordance with the present invention. 
         FIG. 7  shows a fourth apparatus  700  for the vibratory meter  100  provided in accordance with the present invention. 
         FIG. 8  shows a fifth apparatus  800  for the vibratory meter  100  provided in accordance with the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       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 vibratory meter. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these examples that fall within the scope of the present description. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the vibratory meter. As a result, the embodiments described below are not limited to the specific examples described below, but only by the claims and their equivalents. 
       FIG. 1  shows a typical vibratory meter  100 . As depicted, the vibratory meter  100  comprises a Coriolis flow meter. However, the present invention is not limited to applications incorporating Coriolis flow meters, and it should be understood that the present invention could be used with other types of vibratory meters. For example, densitometers may not require that the material flow through flow tubes  101  and  102  to measure density and other parameters of the material in the flow tubes  101  and  102 . Additionally, the present invention can be used in applications other than vibratory meters where an apparatus employed in the application is subjected to undesirable vibrations or movements. 
     As depicted in  FIG. 1 , the vibratory meter  100  comprises a spacer  103  enclosing the lower portion of the flow tubes  101 ,  102  which are internally connected on their left ends to flange  104  via its neck  108  and which are connected on their right ends via neck  120  to flange  105 , and manifold  107 . Also shown in  FIG. 1  are the outlet  106  of flange  105 , left pick-off LPO, right pick-off RPO and driver D. The right pick-off RPO is shown in some detail and includes magnet structure  115  and coil structure  116 . Element  114  on the bottom of manifold spacer  103  is an opening for receiving from meter electronics (not shown) a wire (not shown) that extends internally to driver D and pick-offs LPO and RPO. The meter  100  is adapted to be connected via flanges  104  and  105  to a pipeline or the like when in use. 
       FIG. 2  shows a cut away view of the vibratory meter  100 . This view removes the front portion of manifold spacer  103  so that parts internal to the manifold spacer may be shown. The parts that are shown on  FIG. 2 , but not on  FIG. 1 , include outer end brace bars  201  and  204 , inner brace bars  202  and  203 , right end flow tube outlet openings  205  and  212 , the flow tubes  101  and  102 , curved flow tube sections  214 ,  215 ,  216 , and  217 . In use, the flow tubes  101  and  102  are vibrated about their bending axes W and W′ by the driver D. The outer end brace bars  201  and  204  and the inner brace bars  202  and  203  help determine the location of bending axes W and W′. As depicted, the flow tubes  101  and  102  are coupled to the manifold  107 . 
     It is preferred that the vibratory meter  100  be isolated. For example, it is preferable that undesirable vibrations do not interfere with the Coriolis deflections in the vibratory meter  100 . The interference of the undesirable vibrations on the Coriolis deflections may be reduced by isolating the vibratory meter  100 . In one example, the interference of the undesirable vibrations on the Coriolis deflections may be reduced by isolating the flow tubes  101  and  102  from the flanges  104  and  105 . 
     The Coriolis deflections may be somewhat isolated from the flanges  104  and  105  by employing the outer end brace bars  201  and  204  and the inner brace bars  202  and  203 . However, even with the outer end brace bars  201  and  204  and inner brace bars  202  and  203  restraining the ends of the flow tubes  101  and  102 , the Coriolis deflections may still be coupled to the flanges  104  and  105 . Additional brace bars may further isolate the Coriolis deflections from the flanges  104  and  105 . 
       FIG. 3  shows a detailed isometric cut away view of the vibratory meter  100  at the inlet portion depicting an upper brace bar  302 . The inlet portion of the vibratory meter  100  is selected as an exemplary view. Embodiments described herein with respect to the inlet portion of the vibratory meter  100  are equally applicable to the outlet portion of the vibratory meter  100 . 
     As depicted in  FIG. 3 , the upper brace bar  302  is coupled to the flow tubes  101  and  102  at a distance from the inner brace bar  203 . An analysis was performed to determine if the upper brace bar  302  isolated the Coriolis deflections from the flange  105 . The analysis of this configuration showed that adding the upper brace bar  302  did further isolate of the Coriolis deflections from the flange  105 . However, even with the upper brace bar  302 , the Coriolis deflections were still somewhat coupled to the flange  105 . Accordingly, different configurations of the inner brace bar  203 , the outer end brace bar  204 , and the upper brace bar  302  (e.g., more, thicker, different locations, etc.) may further decouple the Coriolis deflections from the flange  105 . 
     Unfortunately, these other configurations may have undesirable costs. For example, an additional brace bar similar to the upper brace bar  302  may undesirably reduce the amount of space in the vibratory meter  100  available for other components such as sensors. Also, attaching the additional brace bar to the flow tubes  101  and  102  may be difficult thereby undesirably increasing the costs of the vibratory meter  100 . A thicker upper brace bar  302  may be difficult to attach to the flow tubes  101  and  102  because the upper brace bar  302  may have to slide around a curve on the flow tubes  101  and  102  which might require an loose fit between the thicker upper brace bar  302  and the flow tubes  101  and  102 . 
     In the following  FIGS. 4-8 , the present invention provides exemplary embodiments of methods and apparatus for the vibratory meter  100 . For example, the embodiments depicted in the following  FIGS. 4-8  isolate the Coriolis deflections from the flange  105 . The embodiments depicted in  FIGS. 4-8  may also be less costly to implement than other configurations that include the upper brace bar  302 . The following describes analyses to determine if the Coriolis deflections are isolated from the flange  105 . It is appreciated that any appropriate analysis may be employed to determine if an embodiment provided in accordance with the present invention isolates the vibratory meter  100 . 
       FIG. 4  shows a first apparatus  400  for the vibratory meter  100  provided in accordance with an embodiment of the invention. As depicted in  FIG. 4 , the first apparatus  400  includes a lower isolation bar  402  that is coupled to the inner brace bar  203  and the outer end brace bar  204 . The lower isolation bar  402  is depicted as attached (e.g., welded, soldered, etc.) to the inner brace bar  203  and the outer brace bar  204 . Any suitable means of attaching the lower isolation bar  402  may be employed. In this or other embodiments, the lower isolation bar  402  may be formed (e.g., bent, forged, or the like) from the same piece of material as the inner brace bar  203  and the outer brace bar  204 . 
     The lower isolation bar  402  may be adapted (e.g., designed, fabricated, and/or assembled) to isolate the vibratory meter  100 . For example, the lower isolation bar  402  may, when coupled to the brace bars ( 203 ,  204 ), isolate the vibratory meter  100 . The isolation may be in the form of isolating the vibratory meter  100  from vibrations. In the same or alternative embodiments, the lower isolation bar  402  may also isolate the Coriolis deflections from the flange  105 . Also, parameters of the lower isolation bar  402  such as the dimensions (e.g., width, thickness, etc.) or the material properties may be selected to isolate the vibratory meter  100 . Additionally or alternatively, the lower isolation bar  402  may be positioned (e.g., placed in a particular location on the brace bars ( 203 ,  204 )) to isolate the vibratory meter  100 . 
     Such selection of the parameters or the position of the lower isolation bar  402  may be performed in a software simulation, a prototype, and/or a fabrication of the vibratory meter  100 . For example, a finite element analysis (FEA) model of the first apparatus  400  may include simulated flow tubes  101  and  102  that are vibrated by a simulated driver D. The software performing this simulation may then measure reaction forces at the flange  105 . The greater the reaction forces at the flange  105  the more the Coriolis deflections are coupled to the flange  105 . The more the Coriolis deflections are coupled to the flange  105  the less the vibratory meter  100  is isolated. Results from this FEA (or alternative analyses) may then be used to select different parameters or positions of the lower isolation bar  402 . 
     As depicted in  FIG. 4 , the width and thickness of the lower isolation bar  402  is about the width and thickness of the brace bars  203  and  204 . Additionally, the lower isolation bar  402  is depicted as a flat plate. An analysis of the first apparatus  400  for a vibratory meter  100  showed the lower isolation bar  402  further isolated the vibratory meter  100 . In particular, the analysis showed the lower isolation bar  402  further isolated the Coriolis deflections from the flange  105  when compared to the upper brace bar  302 . 
     In other embodiments the lower isolation bar  402  may have other shapes such as curved or triangular surface, etc. The lower isolation bar  402  may also be narrower or wider than the inner brace bar  203  and the outer end brace bar  204 . Additionally or alternatively, the lower isolation bar  402  may have one or more apertures such as holes, slots, etc. These and other parameters of the isolation bar  402  may be selected to isolate the flow meter  100 . 
     In other embodiments of the invention, more than one isolation bar may be provided. In these embodiments, parameters or positions of the isolation bars may be selected to isolate the vibratory meter  100  in a manner similar to that described with respect to the lower isolation bar  402 . For example, parameters of one or more apertures in one or more isolation bars may be selected. In one embodiment, a side isolation bar may include an aperture that is a slot with a width and length selected to isolate the vibratory meter  100 . In the same or alternative embodiments, the height of the side isolation bar may be less than the height of brace bars coupled to the side isolation bar so as to isolate the vibratory meter  100 . Some of these additional embodiments are shown in the following figures. In each of the embodiments shown in the following figures, the one or more isolation bars did further isolate the Coriolis deflections from the flange  105  when compared to the upper brace bar  302 . 
       FIG. 5  shows a second apparatus  500  for the vibratory meter  100  provided in accordance with the present invention. As depicted, the second apparatus  500  includes an upper isolation bar  502  that is coupled to the inner brace bar  203  and the outer end brace bar  204  in addition to the lower isolation bar  402  previously depicted in  FIG. 4 . 
       FIG. 6  shows a third apparatus  600  for the vibratory meter  100  provided in accordance with the present invention. As depicted, the third apparatus  600  includes a first side isolation bar  602  and a second side isolation bar  604 . The third apparatus  600  also includes the lower isolation bar  402  depicted previously in  FIGS. 4 and 5 . However, the third apparatus  600  does not include the upper isolation bar  502  depicted in  FIG. 5 . The first side isolation bar  602  and the second side isolation bar  604  are depicted as coupled to the inner brace bar  203  and the outer brace bar  204 . The first side isolation bar  602  and the second side isolation bar  604  are about the height of the inner brace bar  203  and the outer brace bar  204 . In alternative embodiments, the heights of the first side isolation bar  602  and the second side isolation bar  604  may be different heights to isolate the flow meter  100 . For example, the first side isolation bar  602  may have a height that is smaller than the height of the inner brace bar  203  and the outer brace bar  204 . Also, more or fewer side isolation bars may be selected to isolate the vibratory meter  100 . 
       FIG. 7  shows a fourth apparatus  700  for a vibratory meter  100  provided in accordance with the present invention. As depicted, the fourth apparatus  700  includes the first side isolation bar  602  and the second side isolation bar  604  but does not include the lower isolation bar  402  depicted in  FIG. 6 . 
       FIG. 8  shows a fifth apparatus  800  for a vibratory meter  100  provided in accordance with the present invention. As depicted, the fifth apparatus  800  includes a first side aperture isolation bar  802  and a second side aperture isolation bar  804  that are similar to the first side isolation bar  602  and the second side isolation bar  604  coupled to the inner brace bar  203  and the outer brace bar  204 . The second side aperture isolation bar  804  includes apertures  806   a ,  806   b , and  806   c . The apertures  806   a ,  806   b , and  806   c  are oval in shape. Apertures in the first side aperture isolation bar  802  are not shown. Parameters such as dimensions or shapes of the apertures  806   a ,  806   b , and  806   c  may be selected to isolate the flow meter  100 . For example, a length of a major axis of the oval shape of the apertures  806   a ,  806   b , and  806   c  may be selected to isolate the flow meter  100 . Although three apertures  806   a ,  806   b , and  806   c  are depicted, more or fewer apertures may be selected to isolate the vibratory meter  100 . Also, other aperture shapes may be selected such as square, circular, triangular, etc. The shapes may also be dissimilar. For example, triangle shaped apertures may be in the same isolation bar as oval shaped apertures. Although the apertures  806   a ,  806   b , and  806   c  are depicted in the second side aperture isolation bar  804 , any isolation bar may include apertures. For example, in another embodiment, a lower aperture isolation bar similar to the lower isolation bar  402  may include apertures. 
     The apparatus and method for a vibratory meter according to the invention can be employed according to any of the embodiments in order to provide several advantages, if desired. 
     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 invention. 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 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 additional embodiments within the scope and teachings of the invention. Accordingly, the scope of the invention should be determined from the following claims.