MXPA01008026A - Lateral mode stabilizer for coriolis flowmeter - Google Patents

Abstract

Signal processing of Coriolis flowmeter output signals is improved by increasing the frequency separation between the flow tube drive frequency and unwanted lateral mode vibration frequencies. A cylindrical lateral mode stabilizer surrounds the flow tube near each flow tube end and is positioned between the flow tube and a surrounding balance bar. Axially lateral extensions on opposing circumferential sides of each lateral mode stabilizer element stiffen the flow tube ends for only lateral vibrations. This raises the lateral mode vibration frequency of the flow tube while leaving the drive mode frequency relatively unaffected.

Description

SIDE MODE STABILIZER FOR CORIOLIS FLOW METER FIELD OF THE INVENTION This invention relates to Coriolis flow meters and, more particularly, to an apparatus and method for altering the vibration frequencies of the side-stream flow tube of a Coriolis flow meter. This invention further relates to an apparatus and method for increasing the frequency separation between the resonant pulse frequency of the flow tube and the vibration frequencies of the lateral mode of the flow tube.

PROBLEM Colioris flow meters are characterized by a flow tube through which the material flows while the flow tube is caused to vibrate at its resonant frequency. When no material is flowing, each point on the flow tube vibrates in phase with each other point on the flow tube. Two devices that detect mechanical movement placed at different points on the flow tube generate sinusoidal signals Ref.132087 that have the same phase when no material flows and has a phase difference between them when the material flows. This phase difference is due to the Coriolis forces generated by the flow of the material through the vibrating flow tube. The magnitude of the phase difference between any two points along the length of the flow tube is substantially proportional to the mass flow rate of the material flow. Coriolis mass flow media employs signal processing that determines this phase difference and produces an output signal that indicates mass flow velocity in the company of other information pertaining to material flow. In operation, the flow tube is excited out of phase with an adjacent parallel element, such as a compensation bar for a straight tube Coriolis flow meter. The excitation or impulse force is generated by an exciter or electromechanical motor organ which generates off-phase vibrations of the flow tube and the compensation bar at its combined resonant frequency. For purposes of description, the compensation bar and the flow tube can be said to be driven in a vertical plane by the motor or exciter. These vertical vibrations are relatively large since they are in the first off-phase deflection or inclination mode of the flow tube and the compensation bar and they are activated or driven at their resonant frequency. Colioris deflections of the vibrating flow tube with the flow of the material also occur in the same vertical plane as the vibrations of the impulse or excitation. The deflections of. Coriolis occur at the impulse or excitation frequency but the deflection of the tube has the form of a fold or deflection mode with a higher frequency. Therefore, the amplitude of the Coriolis deflections are considerably smaller than the amplitude of the vibrations of the pulse frequency of the flow tube. Even though the amplitude of the Colioris response is relatively small, it is the Coriolis response that generates the output signals of the mechanical movement that are processed by the apparatus with electronic devices of the meter to generate the flow velocity of the desired mass and other information that belongs to the material that is flowing. The output error of the Coriolis flow meter can typically be 0.15% or less. To achieve this accuracy, it is necessary that the signals of the mechanism that detects the mechanical movement of the Coriolis flow meter are as free as possible from the noise and unwanted signals that can damage the processing of the signals of the mechanism that detects the movement Mechanical Coriolis flow meter. In the operation of a Coriolis flow meter, the signals induced in the mechanisms that detect mechanical movement comprise not only the Coriolis response signals of small amplitude, desired, but also comprise the non-desadas signals that are applied to the processing circuits in the company of the desired Coriolis response signals. The reception of these unwanted signals imparts the ability of the processing circuits to generate the output signals that satisfy the target of less than 0.15% error. Unwanted picking or selection signals can be caused by ambient noise from the surrounding environment. The environmental noise can be due to the proximity to the machinery and the vibrations caused by the traffic of the cars and the nearby railroads. It can also be caused by vibrations in the pipe to which the Coriolis flow meter is connected. The environmental noise can be overcome by the proper assembly of the flow meter to isolate it from the vibrations caused by machinery and traffic. The vibration noise of the connected pipe can be overcome by the proper isolation of the pipe flow meter.

Another source of undesirable signals are the undesirable vibrations in the flow meter. These unwanted vibrations are more difficult to overcome and can be minimized, but not eliminated, by the improved design of the flow meter. All Colioris flow meters have modal shapes that result from the activation or impulse of the flow tube at its resonant frequency. A typical flow meter has vibration modes that are characterized by their shape as follows: Phase deviation (IPB) Lateral in phase (IPL) Deviation out of phase (Activation or impulse) Lateral phase (OPL) Second compensation bar (deviation) Deviation out of phase is the desired activation or impulse mode; the rest are undesirable ways. All of these modes are inherent to any Coriolis flow meter; But a good design can minimize, but not eliminate, unwanted modes. Also, the frequency of these modes changes with the density of the flowing material. When a mode changes the frequency, there is a potential for interaction between nearby modes that can cause the flow meter to become unstable and produce incorrect output data. As previously mentioned, the mode that is desired and used to generate the desired output information of the flow meter is the activation mode or off-phase deflection pulse. It is this mode that generates the Coriolis forces. The resulting Coriolis response is detected by the mechanisms that detect the mechanical movement which generate the signals that are used to provide the output information of the flow meter. The lateral vibrations in phase and the lateral vibrations out of phase are a problem that must be solved in the design of any flow meter. It is a goal of good design of the Coriolis flow meter to ensure that the excitation or pulse frequency is separated from the lateral frequency in the lower phase and the lateral frequency out of the higher phase in an amount sufficient to avoid or minimize the adverse effects of the two different lateral frequencies on the processing of the separate Coriolis response signal. This is necessary so that electronic processing circuits can generate output signals that have the required error of less than 0.15%. The unwanted lateral vibrations can be excited by the pulse frequency due to the asymmetry of the various parts of the flow meter as well as the ambient noise. The existence of lateral vibrations is tolerable provided that the frequencies are separated from the activation or impulse frequency in a sufficient quantity. If this separation is inadequate, the proximity of the lateral frequencies to the frequency of the activation or impulse signal can produce heterodyne frequencies and interactions that produce undesirable signals of the mechanism that detects mechanical movement, which are applied to the electronic processing circuits in company of the desired Coriolis response signal. If these undesirable side-mode signals have an excessive amplitude and / or are close to the frequency of the Corilis response signal, the electronic processing circuits may be unable to process the Coriolis signal to generate the output information that the desired accuracy. It can be observed from the above that it is a problem in the design and operation of the Coriolis flow meters to minimize the adverse impact of the signals generated by the undesirable modes of vibration so that the processing of the Coriolis response signal and The output accuracy of the output signal of the flow meter is not compromised.

SOLUTION The above problem is solved and an advance in the art is achieved by the present invention which comprises the apparatus and a method for altering the vibration characteristics of the flow tubes of the Colioris flow meter so that the frequency of activation or pulse and the frequency of response of Colioris are separated by an adequate amount of lateral vibration frequencies in both phase and out of phase . This increased separation improves the ability of the associated electronic meter devices to process the Colioris response signal so that it can achieve the desired output accuracy. As described above, undesirable signals that can interfere with the processing of Coriolis response signals are due to two causes. The first is caused by the presence of environmental noise. The second is due to undesirable vibrations in the structure of the flow meter. Both of these causes can produce undesirable signals which can alter the processing of the signal, the Colioris response signal. The ambient noise can be reduced to an acceptable level by the improved mechanical isolation of the colioris flow meter from the source of the noise. The signals generated by unwanted flow meter vibrations are mainly due to the asymmetry in the structure of the flow meter. This asymmetry can be due to the imperfect mounting of the exciter or motor organ and / or the mechanisms that detect the mechanical movement in the vertical plane. This asymmetry can also be due to welding or imperfect brass welding operations in the manufacture of the meter. As a result of this asymmetry, a motor or exciter organ, for example, can vibrate the flow tube in a desired vertical plane; but it can also vibrate the flow tube to a lesser extent in an undesirable side plane. Similarly, the fixation of the mechanisms that detect mechanical movement to the flow tube may be less than perfect so that the mechanisms that detect mechanical movement respond mainly to movement in the vertical plane, but they also respond to movement in the lateral plane. In other words, no Coriolis flow meter achieves total perfection in either manufacturing or operation and, as a result, the elements of the flow meter which must operate only in a vertical plane also have an answer, albeit small, in a plane that is perpendicular to the vertical plane. As a result, these elements have an undesirable side component with respect to their vibration as well as with respect to the desired vertical component. This side component, although quite small, can cause undesirable signals in the outputs of the mechanism that detects mechanical movement. The solution to the inevitable presence of lateral vibrations is to alter the structural characteristics of the flow meter to achieve control over the lateral vibration frequencies. This makes it possible for the lateral vibration frequencies to be separated by a larger amount from the frequency of the activation or impulse signal and from the Colioris response signal. The separation of the increased frequency reduces both the amplitude of the lateral vibration and the heterodyne frequencies and their interactions with the Coriolis response signal. The increased separation of the lateral mode frequencies of the activation or impulse frequencies and the Coriolis response frequencies also allows a more facilitated processing of the Coriolis response signal by the associated electronic meter devices. A frequency of the lateral mode that is unacceptably close to the frequency of the Coriolis response signal requires an extremely narrow selectivity and bandwidth in the signal processing circuits. This selectivity and narrow bandwidth is difficult and expensive to achieve. On the contrary, when the vibration frequencies of the lateral mode are separated by an adequate amount of the Coriolis response frequency, the selectivity and width requirements of the electronic element band of the meter are reduced so that the response signal of Coriolis can be processed to achieve the desired accuracy in the output information of the flow meter. The reason for this is that the separation of the increased frequency allows the selectivity of the electronic devices of the meter to reject, or reduce to an acceptable level, the signals of the lateral mode. The apparatus and method of the present invention achieves control of the lateral vibration frequencies by the use of a concentric ring fixed on the ends of the flow tube with lateral axial extensions on the ring that makes contact with the flow tube on each one from its sides. These lateral axial extensions increase the rigidity of the flow tubes towards the lateral vibrations significantly and only moderately affect the vibrations of the flow tube in the vertical plane (of activation or impulse). As a result, an increased separation between the frequency of the vertical flow tube (activation or pulse) and the lateral vibration frequencies of the flow tube is achieved. This separation of the increased frequency eliminates the undesirable consequences of the lateral mode vibration frequencies making the signal processing of the Colioris response signal more facilitated with an improved accuracy in the output information of the flow meter. It can be seen that a first aspect of the invention includes a Colioris flow meter having: a flow tube to receive a flow of material; a compensation bar coupled to the flow tube; a motor or exciter organ that vibrates the flow tube and the compensation bar in a plane of activation or impulse in opposition of phase to each other; the vibrations in the plane of activation or impulse and the flow of material are effective together to induce deflections of Coriolis in the flow tube; Means of detecting mechanical movement coupled to the flow tube that detects Coriolis deflections; the means of detecting the mechanical movement generate signals representing the information pertaining to the flow of the material in response to the detection of the Coriolis deflections; electronic devices of the meter that receive the signals from the means of detecting the mechanical movement and generate the output information pertaining to the flow of the material; the Coriolis flow meter is subjected in the operation to the presence of unwanted lateral vibrations of the flow tube in an off-center plane from the activation or impulse plane; lateral vibrations generate unwanted signals in the means of detecting mechanical movement; the undesirable signals make difficult the processing of the signals of the mechanism that detects the mechanical movement represented by the Coriolis deflections when the separation of the frequency between the activation frequency or impulse and the lateral vibrations is less than a desired quantity; The Colioris flow meter also includes: lateral mode stabilizing means coupled to the flow tube and to the compensation bar; the stabilizing means of the lateral mode alter the frequency of the lateral vibrations and by means of this increase the separation of the frequency between the vibrations of the frequency of activation or impulse and the frequency of the lateral vibrations beyond the desired quantity to facilitate the processing of Colioris signals by the electronic devices of the meter. A second aspect of the invention includes, the Coriolis flow meter of the first aspect wherein the lateral mode stabilizing means includes extension means fixed to a first and a second side of the flow tube to raise the resonant frequency of the lateral vibrations . A third aspect of the invention includes, the Coriolis flow meter of the first aspect wherein the lateral mode stabilizing means includes: a first side mode stabilizer engaging a first end of the compensation bar with a first wall portion of the flow tube; a second side-mode stabilizer that couples a second end of the compensation bar to a second portion of the wall of the flow tube; a ring element on each lateral mode stabilizer having a cylindrical opening for receiving the flow tube - a first and a second lateral extensions on each lateral mode stabilizer extending inwardly from the ring portion towards an axial center flow tube along the lateral sides of the flow tube; the lateral extensions are effective to raise the resonant frequency of the lateral vibrations. A fourth aspect of the invention includes, the Coriolis flow meter - the first aspect wherein: the lateral mode mode stabilizing means comprises a first lateral mode stabilizer coupled to a first end of the compensation bar and a second stabilizer of the lateral mode coupled to a second end of the compensation bar; the first end and the second end of the compensation bar are coupled to a first portion of the wall and a second portion of the wall, respectively, of the flow tube; the compensation bar is oriented substantially parallel to the flow tube; each lateral mode stabilizer has a cylindrical ring element having a circular opening for receiving the flow tube; the cylindrical ring element of each lateral mode stabilizer positioned between an outer wall of the flow tube and an internal wall of the compensation bar; each side-mode stabilizer includes lateral extensions defining the lateral circumferential segments extending axially inwardly from the ring element along the opposite circumferential portions of the flow tube towards a longitudinal center of the flow tube; the lateral extensions are effective to raise the lateral resonant frequency of the flow tube while leaving the resonant frequency of the vibrations of activation or impulse substantially unaltered; the upper and lower circumferential segments of each lateral mode stabilizer define gaps adjacent circumferentially to the lateral circumferential segments defined by the extensions. A fifth aspect of the invention includes, the flow meter of the first aspect wherein: the lateral mode stabilizing means comprises a first lateral mode stabilizer and a second lateral mode stabilizer; each lateral mode stabilizer defines a cylindrical ring element having a circular opening adapted to receive the flow tube; a pair of lateral extensions fixed to the ring-like element oriented circumferentially opposite each other and extending inwardly from the ring element along the opposite lateral surfaces of the flow tube towards a longitudinal center of the flow tube; a pair of vacuum elements positioned circumferentially opposite each other and extending inwardly from the ring element towards the longitudinal center of said flow tube with the vacuum elements which are positioned circumferentially between the pair of extensions; the lateral extensions reinforce or rigidise the flow tube with respect to lateral vibrations while leaving the stiffness of the flow tube relatively unaffected with respect to vibrations in the activation or impulse plane; the pair of the vacuum elements allows, and the lateral extensions allow, that the flow tube remains relatively unaffected with respect to the vibrations of the flow tube in said activation or impulse plane; the reinforcement of the flow tube for lateral vibrations raises the resonant frequency of the lateral vibrations of the flow tube causing an increased frequency separation between the Colioris response frequency and the lateral vibration frequencies of the flow tube. A sixth aspect of the invention includes, the Colioris flow meter of the first aspect and further includes: a substantially cylindrical box enclosing the flow tube and the compensation bar and the lateral mode stabilizing means; first and second connection links to the box coupled to a first end and a second end of the compensation bar and to the flow tube and to the lateral mode stabilizing means; a first external end of the connecting link of the box is connected to a first portion of the inner wall of the box; a second external end of the connecting link of the box is connected to a second internal wall portion of the box opposite circumferentially to the first portion of the inner wall. In a seventh aspect, the flow meter of the sixth aspect wherein the connection link of the box defines: a substantially planar element extending from the first external end to the second external end; a substantially circular opening in a middle portion of the planar element; the circular opening receives the flow tube and the ring portion of the stabilizing means in the lateral mode.

An eighth aspect of the invention includes a method for increasing the frequency spacing between a desired trigger or pulse frequency and an undesired lateral vibration frequency of a Colioris flow meter; the method comprises the steps of: activating or driving a flow tube of the Colioris flow meter in an activation or impulse plane at a resonant frequency of the flow tube and a compensation rod coupled to the flow tube; coupling a laterally stabilizing means to the circumferential side portions of the flow tube to reinforce the side portions with respect to lateral vibrations; the reinforcement is effective to raise the frequency of lateral vibration of the flow tube beyond the frequency of lateral vibration of the flow tube when it is devoid of a coupling with the lateral mode stabilizing means. A ninth aspect of the invention includes, the method of the eighth aspect wherein the coupling step comprises the step of coupling the circumferential lateral extensions on the lateral mode stabilizing means to the opposite circumferential sides of the flow tube to reinforce the sides of the tube of flow with respect to lateral vibrations. A tenth aspect of the invention includes, the method of the ninth aspect and further includes the steps of coupling the flow tube and the lateral mode stabilizing means as well as a compensation bar of the Coriolis flow meter to a connecting link of the box; and coupling the opposite ends of the connecting link of the box to an internal surface of the box enclosing the Colioris flow meter. US Patent No. 5No. 945,609 discloses a mass flow meter for measuring the flow velocity of a fluid by generating a Colioris force in a measuring pipe including a housing and a mechanism for supporting the pipe in the housing. The support mechanism includes a generally cylindrical hollow beam and first and second end support members. The measuring pipe is supported within the hollow beam by the end support elements. A vibrator to vibrate the measuring pipe and two sensors to detect these vibrations are provided in the housing. The effective vibration length of the measuring pipe is set shorter than the effective vibration length of the support mechanism to set the vibration frequency of the pipe higher than the natural frequency of the supporting mechanism, without reducing the stiffness of the support mechanism or use some additional mass. US Patent No. 5,731,527 discloses a Coriolis flow meter whose flow tubes are made at least part of the antiestrophic materials such as fiber reinforced composites. The composite material is formed by controllably orienting the fibers in one direction to increase the tensile strength of the material in this direction. The selected areas of the flow tubes are formed from this composite material to increase the sensitivity of the flow meter and to better separate the vibratory frequencies of the flow meter from the undesirable vibratory frequencies. The circumferentially oriented fibers increase the containment capacity of the internal pressure of the flow tubes. A strain gauge attached to the flow tube flexes with the deformation of the flow tube to indicate the pressure of the internal flow tube.

BRIEF DESCRIPTION OF THE DRAWINGS These and other objects and features and advantages of the invention can be better understood from the reading of the following detailed description of a possible exemplary embodiment thereof taken in conjunction with the drawings in which: Figures 1 and 2 describe the lateral mode stabilizer provided in accordance with the present invention; Figure 3 is a cross-sectional view of a straight tube Coriolis flow meter in which the invention takes shape; Figure 4 is a view of the flow meter taken along line 4-4 of Figure 9. Figure 5 is a cross-sectional side view of a flow meter in which the invention takes shape and; Figure 6 is an isometric representation view of the flow meter of Figure 3 in which the lateral mode stabilizer of Figures 1 and 2 takes shape; Figures 7 and 8 are additional isometric representation views showing the Coriolis flow meter of Figure 3 and in which the lateral mode stabilizer of Figures 1 and 2 takes shape. Figure 9 is a side view of a portion of a flow meter in which the invention takes shape.

DETAILED DESCRIPTION OF THE INVENTION Description of Figures 1, 2 and 3 The present invention comprises a Colioris flow meter in which the lateral mode stabilizer of the present invention takes shape to alter the lateral resonant frequency of the flow tube while leaving the resonant vertical drive or pulse frequency and the frequency of Coriolis response of the flow tube substantially without change. The lateral mode stabilizer is shown in Figures 1 and 2. Figures 3 to 8 show the lateral mode stabilizer which has taken shape in a straight tube Coriolis flow meter. The side-mode stabilizer of Figures 1 and 2 comprises a cylindrical element 101 having a central opening 115 adapted to receive the flow tube 303 of Figures 3-8. The cylindrical element 101 has an outer surface comprising a ring element 204 (shown in Figure 2) and a pair of side extensions 108 each having an end 104 and the side surface 205. The side mode stabilizer 101 has a notch 106 in its upper and lower portion to receive the teeth 411 of a connecting link of the case 401 as best shown in Figures 4, and 6. The stabilizing member 101 of the lateral mode has a pair of side notches 107 which they are used to facilitate a brass welding operation when the element 101 is fixed to the flow tube 303 during the manufacturing process. Figure 1 is an end view of the side mode stabilizer 101 as seen from line 1-1 on Figure 2. The elements 109 on Figure 1 are empty portions of the quadrant of the element 101 and are positioned circumferentially between the two quadrants. which comprise the lateral extensions 108 of the element 101. As shown in Figures 1 and 2, each circumferential void 109 comprises a circumferential segment or quadrant placed in the upper and lower part of the element 101 between the two lateral quadrants comprising the extensions 108. The element 105 is the innermost surface of the empty quadrant element 109. The two lateral extensions 108 are shown on the left and right side of Figure 1 with the element 104 which is the right rear edge of each extension 108 in the Figure 2. In Figure 2, the stabilizer element 101 of the lateral mode has an outer surface which can be functionally divisible and n a ring element 204 and the pair of side extensions 108 having the outer surface 205. The left end of the element 101 in Figure 2 comprises an end surface 202 substantially perpendicular to the ring element 204 as well as an inclined surface 203 interconnecting the outer circumferential portion of the outer surface 202 with the left end of the ring element 204. The surfaces 202 and 203 together with the notches 106 allow the connecting link of the box 401 and its teeth 411 on Figure 6 to engage the notches 106 of the stabilizer element 101 of the lateral mode. The elements 111, 112, 114 and 116 comprise the upper and lower edges of the side extensions 108. Figure 3 is a cross-sectional view of a straight tube Coriolis flow meter 300 in which the present invention takes shape. The flow meter 300 comprises the box 301 which encloses the flow tube 303 and a surrounding concentric compensation bar 302 which are joined at the left and right ends of the compensation bar 302 to the stabilizer element 101 in the lateral mode. The flow tube 303 extends through the end 310 of the box and the portion 315 of the neck and terminates in the projecting elements 306. The left end of the flow tube 303 is element 307; the right end of the flow tube 303 is the element 318. A pair of mechanisms that detect mechanical movement LS and LR comprise the left and right coils 312 and the left and right magnets 313. The flow meter further includes a motor or exciter D, 309, coupled to the compensation bar 302 and to the flow tube 303 to activate or drive the compensation bar and the out-of-phase flow tubes in a manner related to each other at the first resonant frequency of the bending mode of the structure of the compensation bar / flow tube. An activation or impulse signal is generated by the electronic devices 316 of the meter and applied on the conductor 328 to the motor or exciter 309 to vibrate the pair of compensation bars / flow tubes at its first resonant frequency of the deviation mode or flexion. The electronic devices of the meter receive the signals from the mechanisms that detect the mechanical movement LS and RS on the routes 317 and 319 that represent the displacement of Coriolis of the vibrating flow tube with the flow of the material. The electronic devices 316 of the meter process these signals to generate the mass flow and other desired information that pertains to the flow of the material. The output information of the flow meter is applied on the route 320 to a utilization circuit not shown. The element 304 comprises the wall of the box 301. Since Figure 3 is a cross-sectional side view of the flow tube 303, the connection of the stabilizer 101 laterally to the connection link 401 of the box is not shown. Also not shown in Figure 3 is the connection of the end portion 407 of the connection link of the case 401 to the rear inner wall 321 of the case 301. The element 305 represents the space between the internal surface of the compensation rod 302 and the external surface of the flow tube 302.

Description of Figures 4 and 5 Figure 4 depicts a connecting link 401 of the butterfly-shaped box having an external left end 407 connected to the inner wall 408 of the flow meter case 301. The outer right end 403 of the connecting link of the case 401 as shown in Figure 4 is also fixed to the inner wall 408 of the case 301. Figures 4 and 5 together describe how the stabir element 101 of the lateral mode is coupled to the flow tube 303, the compensation bar 302 and the connecting link of the box 401. Figure 4 is an end view of the structure of Figure 5 taken along lines 4-4 of Figure 5. In other words, Figure 4 is a cross sectional end view of the structure of the flow meter taken from a middle portion of the flow meter. In Figure 4, the central portion of the flow tube 303 is shown with the innermost pair of the concentric shading lines that are a cross-section of the wall of the flow tube 303. Fixed to the left and right side portions of the Flow tube wall 303 are the left and right side surfaces 104 of the cylindrical lateral mode stabir element 101. The circumferential edge portions of the left side surfaces 104 are represented by lines 111 and 112 over Figure 4. The corresponding lines on the right side of this Figure are the circumferential ends of the right side surfaces 104 whose circumferential edges are 114 and 116 on Figure 1. The element 113 on Figure 4 is the surface of the lower vacuum 109 as shown in Figure 2 The uppermost line 113 is the innermost surface of the upper vacuum 109 as shown in Figure 2. The next r of circumferential shaded lines extending outward from the center of the flow tube 303 are the walls of the compensation bar 302. This is the cross shading segment 421. The outer surface of the segment 421 on the upper and lower part of Figure 4 defines the portion of the connection link of the box 401 which is fixed to the upper and lower portions of the compensation bar 302. The left side of Figure 4 shows the left end 407 of the connection link of the box 401 connected to the inner surface of the wall 408 of the box. The right side of Figure 4 shows the right end 403 of the connecting link of the box 401 connected to the inner surface of the wall 408 of the box. The element 406 is the junction of the connection link of the box 401 and the compensation bar 302.

Description of Figure 6 Figure 6 describes the flow tube 303, and the compensation bar 302 together with a detail showing how the connection link of the box 401 and the side mode stabir 101 couple the ends of the compensation bar 302 to the tube flow 303. The lateral extensions 108 of the stabir 101 of the lateral mode are clearly shown to be the axially axial ends 104 of the right lateral extension 108. Also shown are the internal ends 113 of the voids or recesses 109 of the lateral mode stabir 101. The teeth 411 on the connecting link of the box 401 are adapted to be inserted into the notches 106 of the stabir 101 in the lateral mode.

Description of Figures 7 and 8 Shown in Figures 7 and 8 is the straight tube Coriolis 300 flow meter having a box 301 enclosing the flow tube 303 and its concentric compensation bar 302. The flow tube 303 extends from the inside of the box 301 through the ends 310 of the left and right box and the neck portions 315 to the projections 306. In Figure 7, the element 307 is the left end of the flow tube 303 and the element 308 is the right end of the 303 flow tube projections 306 make it possible for the flow tube 303 to be connected to a pipe for receiving the material to be processed by the flow meter 300. The holes 801 in the projections 306 make it possible for the flow meter to be coupled to the pipeline. The side mode stabilizer element 101 is shown coupled to each end of the compensation bar 302. The side mode stabilizer 101 couples the compensation bar 302 to the flow tube 303 and to the connection link 401 of the box. The left outer end 407 of each connecting link 401 of the box is shown connected to the inner surface 321 of the wall 321 of the box 301 in Figure 4. The link 410 of the right end 403 of the connecting link of the box 401 in Figure 4 is where the inner wall 321 of the box 301 joins or meets the right end of the connecting link of the box 401. Figures 7 and 8 show the details of the lateral mode stabilizer element 101 and its connection to flow tube 303 and compensation rod 302. In Figure 7, the lateral mode stabilizer 101 is shown coupled to the left and right ends of the compensation bar 302. The lateral mode stabilizer 101 is fixed to the end of the compensation bar 302 and placed between the compensation bar 302 and the tube flow 303. The circumferential ring element 204 of the stabilizer 101 completely surrounds the flow tube 303. The lateral extension 108 on each side of the stabilizer 101 projects axially inward towards the center of the flow tube 303. The exposure of the Figures 7 and 8 are essentially the same except that Figure 8 is a cross sectional view of all the elements of the flow meter while in Figure 7, the side mode stabilizer 101 is shown in greater detail. Accordingly, the notch 107 for brass welding in Figure 1 appears in Figure 8 as a narrow gap between the flow tube 303 and the side extensions 108. It can be seen from the foregoing description of the flow meter 300 that the presence of the lateral mode stabilizer 101 makes it possible for the vertical vibrations of the flow tube 303 to remain relatively unaffected by the lateral mode stabilizer 101 and its side extensions 108. It can also be seen that the lateral extensions 108 are effective in altering the characteristics of lateral vibration of the flow tube 303 as shown in Figures 7 and 8. This lateral extension 108 reinforces the lateral portions of the flow tube 303 to which they are fixed. By doing so, the vibration node or pivot point for the lateral vibrations of the flow tube 303 is effectively moved inwardly to the inner end 104 of each side extension 108. This effectively shortens the length of the tube vibration. 303 flow for lateral vibrations and raises the resonant frequency of lateral vibrations.

Description of Figure 9 Figure 9 is an outer top view of the flow meter of Figure 4. Shown in Figure 9 are the box 301, the connection link 401 of the box, the flow tube 303, the compensation bar 302, the element of ring 204 and lateral extensions 108 of connection link 101 of the box.

Table 1 Flow Meter in the Base Line SG IPL? F Activation? F OPL F 0.5 398 141 539 7 546 1.0 377 96 473 19 492 1.5 351 83 434 35 469 Table 2 Flow meter with lateral mode stabilizer SG IPL? F Activation? F OPL F 0.5 436 178 614 46 660 1.0 418 122 540 48 588 1.5 397 98 495 55 550 Tables 1 and 2 show the benefits provided by the side-mode stabilizer of the present invention. Table 1 shows the figures obtained from an unbalanced flow meter in the baseline for materials that have a relative density of 0.5, 1.0, and 1.5. Table 2 shows the results of a flow meter in which the side-mode stabilizer of the present invention is incorporated. In both Tables 1 and 2, the columns designated SG represent the relative density, the column designated IPL represents the lateral resonant frequency. in phase, the column designated Activation F represents the frequency of resonant activation and the column designated OPL represents a lateral resonant frequency out of phase. The leftmost column designated? F represents the difference in frequency between the lateral frequency in phase and the frequency of activation or impulse. The rightmost column designated? F represents the difference in frequency between the activation or impulse frequency and the out-of-phase lateral resonant frequency. Table 1 indicates that for a relative density of 0.5, the? F between the IPL and the Activation F of the activation or impulse frequency is of 141. This is a separation of the acceptable frequency since it is related to the selectivity of the electronic element of the meter for the processing of the signals of the mechanism that detects the mechanical movement. However, the? F between the F Activation and OPL frequencies for an SG of 0.5 is only 7. This is an unacceptable frequency separation. It can also be seen that the? F between the F Activation and OLP frequencies is 19 and 35 for the relative densities of 1.0 and 1.5 respectively. There are also unacceptable separations.

Table 2 shows the result obtained when a lateral mode stabilizer is incorporated in a flow meter comparable to the flow meter in the baseline of Table 1. It can be seen in Table 2 that for all of the indicated values of the relative density, the? F between the frequencies of the IPL and of the F Activation is considerably increased over that for the comparable meter of Table 1. Also, it can be seen that the? F between the F and OLP Activation frequencies is significantly increased over that for the comparable F of the flow meter in the baseline of Table 1. The Fs of 46, 48, and 55 for the relative densities of 0.5, 1.0 and 1.5 respectively are considerably high and represent a suitable frequency separation to enable the electronic element 316 of the meter to satisfactorily process these signals and obtain the output information of the required accuracy. As can be seen from table 2, the lateral mode stabilizer allows the lateral modes of the flow meter to be increased as well as the frequencies of? F and Activation F and OPL being kept reasonably constant. This allows for greater flexibility in the design since the lateral frequency of the OPL can be reduced without the complication of potential modal crossover or interference. This leads to an increased signal stability meter. In summary, it can be observed from the above that the provision of a lateral mode stabilizer in a flow meter provides the separation of the increased frequency between the desired and unwanted frequencies and thereby allows the signals of the mechanism that detects the mechanical movement of the desired Coriolis meter to be processed more easily to generate the output data of an increased accuracy. It will be expressly understood that the claimed invention will not be limited to the description of the preferred embodiment but covers other modifications and alterations within the scope and spirit of the inventive concept. For exampleAlthough the present invention has been described as comprising a part of a Coriolis flow meter of a single straight tube, it is to be understood that the present invention is not limited and can be used with other types of Coriolis flow meters including the flow meters of a single tube of curved or irregular configuration as well as Coriolis flow meters having a plurality of flow tubes. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (10)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. A Coriolis flow meter: a flow tube to receive the flow of material; a compensation bar coupled to the flow tube; a motor or exciter organ that vibrates the flow tube and the compensation bar in a plane of activation or impulse in opposition of phase to each other; the vibrations in the activation or impulse plane and the material flow are effective together to induce the Coriolis deflections of said flow tube; means of detecting mechanical movement coupled to the flow tube that detects Coriolis deflections; the means of detecting the mechanical movement generate signals representing the information pertaining to the flow of the material in response to the detection of the Coriolis deflections; electronic devices of the meter that receive the signals from the means of detecting the mechanical movement and generate the output information pertaining to the flow of the material; the Coriolis flow meter is subjected in its operation to the presence of undesirable lateral vibrations of the flow tube in a plane substantially perpendicular to the plane of activation or impulse; lateral vibrations generate unwanted signals in the means of detecting mechanical movement; the unwanted signals make it difficult to process the signals of the mechanical movement detecting device representing the Coriolis deflections when the separation of the frequency between the activation frequency or pulse and the lateral vibrations is less than a desired amount; characterized by: lateral mode stabilizing means coupled to the flow tube and to the compensation bar; the stabilizing means of the lateral mode alter the frequency of the lateral vibrations to a greater degree than the vibrations of activation or impulse and by which the separation of the frequency between the vibrations of the frequency of activation or impulse and the frequency of the lateral vibrations so that the separation is larger than the desired amount to facilitate the processing of the Coriolis signals by the electronic devices of the meter.
2. 2. The Coriolis flow meter according to claim 1, characterized in that the lateral mode stabilizing means includes extension means fixed to a first and a second side of the flow tube to raise the resonant frequency of the lateral vibrations.
3. 3. The Coriolis flow meter according to claim 1, characterized in that the lateral mode stabilizing means includes: a first lateral mode stabilizer coupling a first end of the compensation bar to a first portion of the tube wall flow; a second side-mode stabilizer that couples a second end of the compensation bar to a second portion of the wall of the flow tube; a ring element on each stabilizer of the side modc having a circular opening for receiving the flow tube- a first and a second lateral extensions on each lateral mode stabilizer extending axially inwardly from the ring element towards a longitudinal center of the flow tube along the lateral sides of the flow tube - the lateral extensions are effective in raising the resonant frequency of the lateral vibrations.
4. 4. The Coriolis flow meter according to claim 1, further characterized in that: the lateral mode stabilizing means comprises a first lateral mode stabilizer coupled to a first end of the compensation bar and a second lateral mode stabilizer coupled to a second end of the compensation bar; the first end and the second end of the compensation bar are coupled to a first portion of the wall and a second portion of the wall, respectively, of the flow tube; The compensation bar is oriented substantially parallel to the flow tube. Each lateral mode stabilizer has a cylindrical ring element having a circular opening for receiving the flow tube; the cylindrical ring element of each lateral mode stabilizer is positioned between an outer wall of the flow tube and an inner wall of the compensation bar; each side-mode stabilizer includes the lateral extensions defining the lateral circumferential segments extending axially inwardly from the ring element along the opposite circumferential portions of the flow tube towards a longitudinal center of the flow tube; the lateral extensions are effective to raise the lateral resonant frequency of the flow tube while leaving the resonant frequency of the activation or impulse vibrations substantially unaltered; the upper and lower circumferential segments of each lateral mode stabilizer define gaps adjacent circumferentially to the lateral circumferential segments defined by the extensions.
5. 5. The Coriolis flow meter according to claim 1, further characterized in that: the lateral mode stabilizing means comprises a first lateral mode stabilizer and a second lateral mode stabilizer; each lateral mode stabilizer defines a cylindrical ring element having a circular opening adapted to receive the flow tube: a pair of lateral extensions attached to the ring element oriented circumferentially opposite each other and extending inwardly from the ring element along the opposite lateral surfaces of the flow tube towards a longitudinal center of the flow tube; a pair of upper and lower circumferential segments defining the empty elements positioned circumferentially opposite each other and extending inwardly from the ring element towards the longitudinal center of the flow tube with the empty elements that are positioned circumferentially between the pair of extensions; the lateral extensions reinforce the flow tube with respect to lateral vibrations while leaving the stiffness of the flow tube relatively unaffected with respect to vibrations in the activation or impulse plane; the pair of upper and lower circumferential segments defining the empty elements and the lateral extensions allow the flow tube to remain relatively unaffected with respect to the vibrations of the flow tube in the activation or impulse plane; the reinforcement of the hollow tube for lateral vibrations raises the resonant frequency of the lateral vibrations of the flow tube and increases the separation of the frequency between the vibrations of the activation or impulse frequency and the vibrations of the lateral frequency of the flow tube.
6. 6. The Coriolis flow meter according to claim 1, characterized in that it further includes: a substantially cylindrical box enclosing the flow tube and the compensation bar and the lateral mode stabilizing means; a first and a second connection links of the box coupled to a first end and a second end of the compensation bar and to the flow tube and to the lateral mode stabilizing means; a first external end of the connecting link of the box is connected to a first portion of the inner wall of the box; a second external end of the connecting link of the box is connected to the inner wall portion of the box opposite circumferentially to the first portion of the inner wall.
7. The flow meter according to claim 6, characterized in that the connection link of the box defines: a substantially flat element extending from the first external end to the second external end; a substantially circular opening in a middle portion of the planar element; the circular opening receives the compensation bar and the flow tube and the ring element of the lateral mode stabilizing means.
8. 8. An operating method of the Coriolis flow meter according to claim 1, for increasing the frequency spacing between a desired trigger or pulse frequency and an unwanted lateral vibration frequency of the Coriolis flow meter; the method comprises the steps of: activating or driving the flow tube of the Coriolis flow meter in a pulse plane at a resonant frequency of the flow tube and the compensation bar coupled to the flow tube; characterized by the additional steps of: coupling the lateral mode stabilizing means having the lateral extensions to the circumferential side portions of the flow tube to reinforce the lateral portions of said flow tube with respect to lateral vibrations; the reinforcement is effective to raise the vibration frequency of activation or impulse of the flow tube to an amount greater than the frequency of the lateral vibration of the flow tube when not in engagement with the stabilizing means of the lateral mode. The method according to claim 8, characterized in that the step of the coupling comprises the step of coupling the circumferential lateral extensions on the lateral mode stabilizing means to the opposite circumferential sides of the flow tube to reinforce the sides of the flow tube with respect to lateral vibrations. The method according to claim 9, characterized in that it also comprises the passages of the flow tube coupling and the lateral mode stabilizing means as well as the compensation bar of the Coriolis flow meter with a connection link of the box; and coupling the opposite ends of the connecting link of the box with an internal surface of a box enclosing the Coriolis flow meter.