Measuring transducer of the vibration type

0001The invention relates to a, in particular suitable for use in a Coriolis mass flow meter, transducer of the vibration type with at least one at least temporarily vibrating measuring tube for guiding medium to be measured, a counteroscillator, which is fixed to form a first coupling zone inlet side of the measuring tube and the is fixed to the measuring tube on the outlet side to form a second coupling zone, an exciter arrangement for driving at least the measuring tube and a sensor arrangement for detecting vibrations of at least the measuring tube.

0002Such in-line gauges with a vibration-type transducer have long been known and have become equally established in industrial use. Examples of such transducers, esp. The use thereof in Coriolis mass flow meters are, for example in the<patcit id="pcit0001" dnum="EP317340A"><text>EP-A 317 340</text></patcit>, of the <patcit id="pcit0002" dnum="US4823614A"><text>US-A 48 23 614</text></patcit>, of the <patcit id="pcit0003" dnum="US5291792A"><text>US-A 52 91 792</text></patcit>, of the <patcit id="pcit0004" dnum="US5398554A"><text>US-A 53 98 554</text></patcit>, of the <patcit id="pcit0005" dnum="US5476013A"><text>US-A 54 76 013</text></patcit>, of the <patcit id="pcit0006" dnum="US5602345A"><text>US-A 56 02 345</text></patcit>, of the <patcit id="pcit0007" dnum="US5691485A"><text>US-A 56 91 485</text></patcit>. <patcit id="pcit0008" dnum="US5796010A"><text>US Pat. No. 5,796,010</text></patcit>, of the <patcit id="pcit0009" dnum="US5796012A"><text>US Pat. No. 5,796,012</text></patcit>, of the <patcit id="pcit0010" dnum="US5945609A"><text>US-A 59 45 609</text></patcit>, of the <patcit id="pcit0011" dnum="US5979246A"><text>US-A 59 79 246</text></patcit>, of the <patcit id="pcit0012" dnum="US6397685B"><text>US-B 63 97 685</text></patcit>, of the <patcit id="pcit0013" dnum="US6691583B"><text>US-B 66 91 583</text></patcit>, of the <patcit id="pcit0014" dnum="US6840109B"><text>US-B 68 40 109</text></patcit>. <patcit id="pcit0015" dnum="US7077014B"><text>US-B 70 77 014</text></patcit>. <patcit id="pcit0016" dnum="US7017424B"><text>US-B 70 17 424</text></patcit>, of the <patcit id="pcit0017" dnum="US20070186685A"><text>US-A 2007/0186685</text></patcit>, of the <patcit id="pcit0018" dnum="US20070119265A"><text>US-A 2007/0119265</text></patcit>, of the <patcit id="pcit0019" dnum="US20070119264A"><text>US-A 2007/0119264</text></patcit>, of the <patcit id="pcit0020" dnum="WO9940394A"><text>WO-A 99 40 394</text></patcit>, of the <patcit id="pcit0021" dnum="WO0102816A"><text>WO-A 01 02 816</text></patcit> or the <patcit id="pcit0022" dnum="WO0014485A"><text>WO-A 00 14 485</text></patcit> described.

0003Each of the transducers shown therein comprises at least one substantially straight, in operation vibrating measuring tube for guiding the medium, which communicates measuring tube via an inlet side inlet tube piece and communicates via an outlet side opening Auslaßrohrstück with the pipe.

0004Further, each of the transducers shown each comprise at least one one-piece or multi-piece counter-oscillator, which is coupled to the measuring tube on the inlet side to form a first coupling zone and the output side coupled to the measuring tube to form a second coupling zone and which is also vibrated at least partially in operation , For example, in the<patcit id="pcit0023" dnum="US5291792A"><text>US-A 52 91 792</text></patcit>, of the <patcit id="pcit0024" dnum="US5796010A"><text>US Pat. No. 5,796,010</text></patcit>, of the <patcit id="pcit0025" dnum="US5945609A"><text>US-A 59 45 609</text></patcit>, of the <patcit id="pcit0026" dnum="US7077014B"><text>US-B 70 77 014</text></patcit>, of the <patcit id="pcit0027" dnum="US20070119264A"><text>US-A 2007/0119264</text></patcit>, of the <patcit id="pcit0028" dnum="WO0102816A"><text>WO-A 01 02 816</text></patcit> or even the <patcit id="pcit0029" dnum="WO9940394A"><text>WO-A 99 40 394</text></patcit> shown transducers with a single, substantially straight measuring tube are the latter and the counteroscillator, as in conventional, industrially suitable transducers quite common, aligned substantially coaxially with each other. Moreover, in marketable transducers of the aforementioned type and the counteroscillator is usually substantially tubular and substantially straight and also arranged in the transducer such that the measuring tube is at least partially encased by the counteroscillator and measuring tube and counteroscillator are aligned substantially coaxially.

0005Transducers of the type in question further comprise an excitation device, the measuring tube in operation, driven by a suitably conditioned electrical drive signal, by means of at least one acting on it electro-mechanical, esp. Electro-dynamic, vibration exciter to bending vibrations usually predominantly or exclusively in a single imaginary - hereinafter referred to as the primary vibration level - excited tube vibration plane, which intersects the two coupling zones imaginary. Furthermore, such transducers have a sensor arrangement with, in particular electro-dynamic, vibration sensors for at least selective detection of inlet-side and outlet-side vibrations of the measuring tube and for generating influenced by the mass flow electrical sensor signals.

0006The exciter assembly has at least one electrodynamic and / or differentially acting on measuring tube and counteroscillator, vibration, while the sensor assembly includes an inlet side, usually also electrodynamic, vibration sensor and a substantially identical outlet-side vibration sensor. In markgängigen transducers with a single measuring tube and a counteroscillator coupled thereto, the vibration exciter is usually formed by means of a at least temporarily flowed through by a current and at least temporarily interspersed by a magnetic coil and a coil interacting with the at least one coil, esp. Submerged in this anchor, which is fixed according to the measuring tube. In addition, in conventional transducers, the exciter assembly is usually designed and placed in the transducer that it acts substantially centrally on the measuring tube. In most cases, the at least one vibration exciter and insofar as the exciter arrangement is further, as for example in the in the<patcit id="pcit0030" dnum="US5796010A"><text>US Pat. No. 5,796,010</text></patcit>, of the <patcit id="pcit0031" dnum="US6840109B"><text>US-B 68 40 109</text></patcit>, of the <patcit id="pcit0032" dnum="US7077014B"><text>US-B 70 77 014</text></patcit> or the <patcit id="pcit0033" dnum="US7017424B"><text>US-B 70 17 424</text></patcit> proposed transducers shown at least selectively along an imaginary central peripheral line of the measuring tube fixed to the outside of this, while, for example, in the <patcit id="pcit0034" dnum="US4823614A"><text>US-A 48 23 614</text></patcit> the excitation arrangement is formed by means of two non-fixed in the center of the measuring tube to this vibration exciter.

0007In most transducers of the type described, the vibration sensors of the sensor arrangement, as already indicated, constructed according to the same principle as the aforementioned vibration exciter. Accordingly, the vibration sensors of such a sensor arrangement are usually each formed by means of at least one usually fixed to the counteroscillator, at least temporarily flowed through by a current and at least temporarily interspersed by a magnetic coil and a fixed to the measuring tube, cooperating with the at least one coil anchor. Each of the aforementioned coils is also connected by means of at least one pair of electrical leads to the aforementioned operating and evaluation electronics of the in-line measuring device. The connection lines are usually performed as short as possible from the coils on the counteroscillator towards the converter housing. In addition to the measures provided for detecting vibrations of the measuring tube vibration sensors, the transducer, as, inter alia, in the<patcit id="pcit0035" dnum="EP831306A"><text>EP-A 831 306</text></patcit>, of the <patcit id="pcit0036" dnum="US5736653A"><text>US-A 57 36 653</text></patcit>, of the <patcit id="pcit0037" dnum="US5381697A"><text>US-A 53 81 697</text></patcit> or the <patcit id="pcit0038" dnum="WO0102816A"><text>WO-A 01/02 816</text></patcit> proposed, even more, esp. The detection of rather secondary quantities such as temperature, acceleration, strain, voltage, etc., serving at least by means of measuring tube, counteroscillator and the respective excitation and sensor assembly formed thereon inner part or arranged in the vicinity Have sensors.

0008Finally, everyone in the <patcit id="pcit0039" dnum="US5291792A"><text>US-A 52 91 792</text></patcit>, of the <patcit id="pcit0040" dnum="US5945609A"><text>US-A 59 45 609</text></patcit>, of the <patcit id="pcit0041" dnum="US7077014B"><text>US-B 70 77 014</text></patcit>, of the <patcit id="pcit0042" dnum="US20070119264A"><text>US-A 2007/0119264</text></patcit>, of the <patcit id="pcit0043" dnum="WO0102816A"><text>WO-A 01 02 816</text></patcit> or even the <patcit id="pcit0044" dnum="WO9940394A"><text>WO-A 99 40 394</text></patcit> shown transducer, esp. Directly on the inlet pipe piece and the outlet pipe piece fixed, the measuring tube with counter-oscillator coupled thereto and the proposed excitation and sensor arrangement enclosing additional converter housing, while, for example, in the in the <patcit id="pcit0045" dnum="US4823614A"><text>US-A 48 23 614</text></patcit> shown transducer, the converter housing <i>so to say</i> is formed by the counteroscillator itself or, in other words, transducer housing and counteroscillator one and the same unit.

0009An advantage of measuring transducers with straight measuring tube is compared to those with curved measuring tube, for example, that the measuring tube in almost any mounting position, esp. Even after an in-line cleaning, with high security without residue even empty. Furthermore, such measuring tubes are compared to a curved measuring tube much easier and therefore cheaper to produce and cause in operation usually a lower pressure drop.

0010A straight measuring tube is known to cause Coriolis forces in the medium flowing therethrough when the same measuring tube is excited to bending vibrations in the primary plane of vibration according to a first mode of natural vibration, the so-called drive or payload mode. In conventional transducers of the aforementioned type, for example, such as in the<patcit id="pcit0046" dnum="US5291792A"><text>US-A 52 91 792</text></patcit>, of the <patcit id="pcit0047" dnum="US6840109B"><text>US-B 68 40 109</text></patcit>, of the <patcit id="pcit0048" dnum="US7077014B"><text>US-B 70 77 014</text></patcit> or the <patcit id="pcit0049" dnum="US7017424B"><text>US-B 70 17 424</text></patcit> proposed, in which the measuring tube is oscillated in Nutzmode primarily in the imaginary primary plane of vibration, these Coriolis forces in turn cause selbigen bending oscillations coplanare Nutzmodode - ie also performed in the primary vibration level - bending vibrations according to a second natural mode of mostly higher order, but in any case other symmetry properties - the so-called Coriolis or Meßmode - superimposed. As a result of the bending oscillations in the Coriolis mode, the vibrations detected on the inlet side and on the outlet side by means of the sensor arrangement have a measurable phase difference which is also dependent on the mass flow rate.

0011Usually, the measuring tubes of such transducers, esp. Such, which are used in Coriolis mass flow meters, excited in the Nutzmode on a momentary resonance frequency of the first natural mode, esp. At constant-controlled oscillation amplitude. Since this resonant frequency in particular depends on the instantaneous density of the medium, at least the density of flowing media can be measured directly by means of commercially available Coriolis mass flow meters in addition to the mass flow rate.

0012A particular problem of the above-described transducer with straight measuring tube consists, as for example in the <patcit id="pcit0050" dnum="US5291792A"><text>US-A 52 91 792</text></patcit> or <patcit id="pcit0051" dnum="US7077014B"><text>US-B 70 77 014</text></patcit> discussed, however, in that they not only have the above-mentioned natural vibration modes in which the measuring tube performs bending vibrations in said primary vibration level, but also such natural vibration mode in which the measuring tube bending vibrations in another imaginary, to the primary vibration level in the substantially orthogonal and the two coupling zones can perform imaginary intersecting secondary vibration plane, and that those vibration modes in the secondary vibration plane naturally have approximately the same resonant frequency without taking special measures as the respective corresponding vibration mode in the primary vibration plane. In other words, in the case of transducers of the type in question with a straight measuring tube, any measurement inaccuracies can result from that in addition to the desired excited Nutzmode in the primary vibration level undesirable and so far disturbing vibrations in the secondary vibration plane occur, which are very close to the oscillation frequencies of the Nutzmodes. In the same way as the payload mode in the primary oscillation plane, coplanar additional oscillation modes caused by corresponding Coriolis forces would then also be induced in the secondary oscillation plane to the undesirably excited, even-frequency oscillation mode. The cause of such disturbances can be, for example, vibrations in the connected pipeline or also, for the most part, broadband noise emanating from the flowing medium. which are very close to the oscillation frequencies of the Nutzmodes. In the same way as the payload mode in the primary oscillation plane, coplanar additional oscillation modes caused by corresponding Coriolis forces would then also be induced in the secondary oscillation plane to the undesirably excited, even-frequency oscillation mode. The cause of such disturbances can be, for example, vibrations in the connected pipeline or also, for the most part, broadband noise emanating from the flowing medium. which are very close to the oscillation frequencies of the Nutzmodes. In the same way as the payload mode in the primary oscillation plane, coplanar additional oscillation modes caused by corresponding Coriolis forces would then also be induced in the secondary oscillation plane to the undesirably excited, even-frequency oscillation mode. The cause of such disturbances can be, for example, vibrations in the connected pipeline or also, for the most part, broadband noise emanating from the flowing medium.

0013As a consequence of <i>in practice</i> almost inevitable cross sensitivities of the vibration sensors to vibrations in the secondary vibration level causes the sensor signals supplied under such circumstances proportionally reflect both vibrations of the measuring tube in the primary vibration level as well as corresponding vibrations of the measuring tube secondary vibration level in a significant extent for the accuracy of measurement , an assignment of the corresponding signal components to the primary or secondary vibration plane is practically impossible because of the substantially equal frequencies of corresponding vibrations.

0014Moreover, with a sufficiently strong mechanical coupling of vibration modes of both vibration levels, a transfer of vibration energy - spontaneously or periodically - from the primary to the secondary vibration plane or vice versa from the secondary to the primary vibration plane is possible. As a result, the sensor signals may, for example, have a characteristic harmonic which is entirely detrimental to their signal processing as well as to the vibration control based on the sensor signals. Furthermore, vibration movements in the secondary vibration plane, be it indirectly excited by external disturbances directly or indirectly via the aforesaid energy transfer from the primary to the secondary vibration plane, can cause the sensor signals to have temporarily excessive signal levels, with the result that

0015To suppress such in the secondary vibration level performed, a total of very harmful vibrations, it is common to increase effective for these vibrations rigidity of the measuring tube with respect to a vibration in the primary vibration level effective rigidity of the measuring tube at substantially constant effective masses and thus resonant frequencies effectively separate from each other by mutually corresponding vibration modes of the primary and secondary vibration planes, respectively. Typically, this frequency distances of more than 30 Hz are sought.

0016In the in the <patcit id="pcit0052" dnum="US5602345A"><text>US-A 56 02 345</text></patcit> For this example, the use of inlet and outlet side in addition to the respective coupling zones on the respective measuring tube additionally attached, designed as flat webs spring elements proposed. As a further possibility for the separation of vibration modes in the primary vibration plane of corresponding vibration modes in the secondary vibration plane is further in the<patcit id="pcit0053" dnum="US5291792A"><text>US-A 52 91 792</text></patcit> shown. In the transducer proposed there, the effective for oscillations in the secondary vibration plane stiffness of the measuring tube is increased by the fact that the measuring tube in its center with a corresponding acting as in the radial direction to measuring tube and counter-oscillator extending arranged in the transducer, here U shaped, stiffening spring trained spring element is acted upon, which does not appreciably affect the rigidity of the measuring tube for the Coriolis mode in the primary plane of vibration. As a result, it can be achieved that the oscillation frequency of the oscillations in the useful mode is sufficiently strongly differentiated from the frequency of undesired, ie disturbing oscillations, and thus the influence of such disturbing oscillations is largely suppressed.

0017However, a disadvantage of such a centrally acting, more selectively acting on the measuring tube stiffening spring is to be seen in the fact that unabated asymmetric vibration modes can be excited in the secondary vibration level, such as the counterpart to the Coriolis mode in the primary vibration plane, along with the above described disadvantages. In addition, such a central, ie at the location of maximum vibration amplitude acting stiffening spring must be designed according to mechanically stable and vibration resistant. On the other hand, however, are also in the<patcit id="pcit0054" dnum="US5602345A"><text>US-A 56 02 345</text></patcit> proposed webs only with relatively high effort to attach and adjust, esp. Even with application of this principle to a single measuring tube with coaxially arranged, tubular counteroscillator.

0018An object of the invention is therefore to improve transducers of the aforementioned type with at least one temporarily vibrating measuring tube and a counter-oscillator fixed on the measuring tube to the effect that, in comparison with the solutions presented, the separation of the resonant frequencies of the oscillation modes in the primary and secondary vibration level can be achieved. This in particular even with respect to at least the aforementioned webs comparable or lower manufacturing costs.

0019To achieve the object, the invention consists in a vibration-type transducer for a medium flowing in a pipeline, according to independent claim 1. Advantageous embodiments of the invention are set forth in the dependent claims.

0020Moreover, the invention consists in the use of a transducer of the above type in an in-line measuring device, for example as Coriolis mass flowmeter, density meter, viscosity measuring device or the like, for measuring and / or monitoring at least one parameter, for example a mass flow rate of a density and / or a viscosity of a medium flowing in a pipeline.

0021A basic idea of ​​the invention consists, inter alia, in the use of frequency elements instead of merely centered spring elements acting on the measuring tube such Federlemente attack both away from the center and from the aforementioned coupling zones and effectively suppress symmetrical as well as asymmetric disturbances. This has the advantage that so disturbances of the mostly asymmetric Meßmodes, for example, as a result of unilaterally applied to the pipeline in-line meter attacking and / or wobbling movements of the in-line measuring device about one of its main axes of inertia causing time-varying forces, be very effectively suppressed in a very simple way.

0022A particularly effective frequency separation can be achieved, for example, by using substantially rod-shaped or bar-shaped spring elements which are arranged in the transducer so that they extend substantially in the secondary vibration plane. A relative movement between the absorber tube and the measuring tube perpendicular to the utility and Coriolis mode in the primary oscillation plane is thereby practically blocked. This in particular when selbige spring elements are arranged in the transducer so that they extend substantially radially to the measuring tube and / or counter-oscillator. In addition, bar-shaped spring elements, esp. In comparison to the mentioned end fixed to the measuring tube bars can be produced and assembled inexpensively,

0023In the event that the spring elements are arranged in the transducer, that each of them acts directly on a peripheral line of the measuring tube, along which the respective vibration sensor is placed, at least there can be almost completely excluded relative movements between measuring tube and counteroscillator. This leads to the further advantage that disturbances acting on the vibration sensor from the outside in the secondary oscillation direction can no longer generate a nominally high-level current signal, even if this also has a certain cross-sensitivity in this oscillation direction.

0024Hereinafter, the invention and advantageous embodiments thereof will be explained with reference to an embodiment which is illustrated in the figures of the drawing; the same parts are provided in the figures otherwise with the same reference numerals. If it is useful for the sake of clarity, reference numerals already mentioned are omitted in the following figures. In the individual are in:<ul><li><figref idref="f0001">Fig. 1</figref> an in-line measuring device insertable into a pipeline for measuring at least one parameter of a medium carried in the pipeline,</li><li><figref idref="f0002">Fig. 2</figref> cut in a side view of an embodiment of an in-line measuring device of <figref idref="f0001">Fig. 1</figref> suitable vibration-type transducers with a measuring tube and a counter-oscillator as well as end-side arms,</li><li><figref idref="f0002">Fig. 3</figref> the transducer of <figref idref="f0002">Fig. 2</figref> shown in a cross section</li><li><figref idref="f0002">Fig. 4</figref> the transducer of <figref idref="f0002">Fig. 2</figref> shown in another cross section with a spring element,</li><li><figref idref="f0003">FIGS. 5</figref> schematically bending lines of the measuring tube and the a to d counteroscillator, each oscillating in a lateral bending mode in a primary plane of vibration of the transducer, shown</li><li><figref idref="f0004">FIGS. 6a, b</figref> in two different sectional views a variant of a transducer according to <figref idref="f0002">Fig. 2</figref> shown with two spring elements,</li><li><figref idref="f0005">FIGS. 7a, b</figref> in two different sectional views of another variant of a transducer according to <figref idref="f0002">Fig. 2</figref> shown with two spring elements,</li><li><figref idref="f0006">FIGS. 8a, b</figref> in two different sectional views, a further variant of a transducer according to <figref idref="f0002">Fig. 2</figref> shown with four spring elements, and</li><li><figref idref="f0007">Fig. 9</figref> schematically a section of a transducer according to <figref idref="f0002">Fig. 2</figref> shown with a fixed to the measuring tube and counter-oscillator spring element.</li></ul>

0025In the <figref idref="f0001">Fig. 1</figref> is an insertable into a - not shown - piping, for example, as a Coriolis mass flowmeter, density meter, Viskositätsmeßgerät or the like formed in-line measuring device, the measuring and / or monitoring of at least one parameter, such as a mass flow, a density, viscosity, etc., of a medium flowing in the pipe. The in-line measuring device comprises for this purpose a to a in an appropriate electronics housing 200 accommodated - not shown here - operating and evaluation of the in-line meter electrically connected transducers of the vibration type, which is flowed through during operation according to the medium to be measured ,

0026In the <figref idref="f0002">Fig. 2 to 4</figref> is an example of a concrete embodiment of the basic structure of such a transducer of the vibration type shown schematically in different sectional views. In addition, the principal mechanical structure and its mode of action of the transducer shown by way of example with those of the in the<patcit id="pcit0055" dnum="US20070119265A"><text>US-A 2007/0119265</text></patcit>. <patcit id="pcit0056" dnum="US20070119264A"><text>US-A 2007/0119264</text></patcit>. <patcit id="pcit0057" dnum="US6691583B"><text>US-B 66 91 583</text></patcit>, of the <patcit id="pcit0058" dnum="US6840109B"><text>US-B 68 40 109</text></patcit> shown transducer comparable. Further embodiments and embodiments of the transducer according to the invention as well as details thereof are also in the<figref idref="f0004">FIGS. 6a, 6b</figref>. <figref idref="f0005">7a, 7b</figref>. <figref idref="f0006">8a, 8b</figref> and 9 are shown.

0027The transducer serves to generate in a medium flowing through mechanical reaction forces, eg mass flow-dependent Coriolis forces, density-dependent inertial forces and / or viscosity-dependent frictional forces measurable, esp. Sensory detectable, act back on the transducer. Derived from these reaction forces can thus be known in the art, for example, a mass flow<i>m,</i> a density ρ and / or a viscosity η of the medium are measured. For guiding the medium transducer comprises at least one - in the embodiment shown here, only substantially straight - measuring tube 10, which is vibrated during operation and thereby repeatedly oscillated elastically around a static rest position, wherein the transducer has at least a first natural vibration mode in which at least the measuring tube can execute bending oscillations in an imaginary primary vibration plane XZ. Incidentally, this imaginary primary vibration level XZ practically also corresponds to the plane of the drawing<figref idref="f0003">Fig. 5a - 5d</figref>, In addition to the first natural vibration mode in the imaginary primary vibration level XZ, the transducer also naturally has at least a second natural vibration mode in which at least the measuring tube can perform bending vibrations in an imaginary secondary vibration plane YZ substantially orthogonal to the imaginary primary vibration plane XZ.

0028In order to minimize disturbances acting on the measuring tube 10 as well as to reduce vibrational energy emitted by the transducer to the connected pipeline, a counter-oscillator 20 is provided in the measuring transducer, which is substantially straight and substantially parallel to the measuring tube 10. This one is, as well as in<figref idref="f0002">Fig. 2</figref> shown to form a - practically an inlet end of the measuring tube 10 defining - first coupling zone 11 # inlet side and the formation of a - virtually an outlet end of the measuring tube 10 defining - second coupling zone 12 # outlet side respectively fixed to the measuring tube 10. The counteroscillator 20 may be tubular or box-shaped and connected, for example, at the inlet end and at the outlet end to the measuring tube 10 that, as is quite usual in such transducers, is aligned substantially coaxially to the measuring tube 10 and thus the measuring tube 10 from the counteroscoric 20th at least partially sheathed. In addition, it may be advantageous if the counteroscillator 20 is designed much heavier than the measuring tube 10th

0029For passing the medium to be measured, the measuring tube 10 is connected to the inlet pipe section 11 via an inlet side in the region of the first coupling zone and via an outlet side in the region of the second coupling zone, in particular to the inlet pipe section 11 substantially identical to the outlet pipe section 12. or laxatives - not shown here - connected pipeline. Inlet pipe piece 11 and outlet pipe piece 12 are substantially straight in the illustrated embodiment and aligned with each other, the measuring tube 10 and an imaginary longitudinal axis L practically connecting the coupling zones. Advantageously, the measuring tube 10, inlet and outlet pipe 11, 12 may be made in one piece, so that their manufacture can serve as a single tubular semi-finished.

0030According to one embodiment of the invention, the measuring tube is further formed so that it extends between the two coupling zones with substantially constant, esp. Kreisringförmigem, cross-section. In particular, it is further provided that the measuring tube 10 is formed substantially cylindrical.

0031In operation of the transducer, the measuring tube 10 is - as already mentioned several times - at least temporarily to lateral bending vibrations in the imaginary primary vibration level XZ, esp. In the range of a natural resonant frequency of a corresponding natural vibration mode, so excited that it is in this so-called Nutzmode at least proportionally, in particular predominantly, ausiegt according to a natural first mode of natural vibration. The bending oscillations in the payload mode are aligned substantially transversely to an essentially coincident, in particular coincident, bending oscillation axis which is essentially coincident with the longitudinal axis L and connects the two coupling zones 11 #, 12 # to one another imaginarily. According to one embodiment of the invention, it is further provided in this case

0032According to a further embodiment of the invention, the measuring tube 10 is thereby at a vibration frequency, f_exc, excited as precisely as possible a natural resonance frequency of the so-called <i>f1</i>-Eigenmodes of the measuring tube 10 corresponds, so a symmetrical eigenmode in which, as in <figref idref="f0003">FIGS. 5b to 5d</figref> shown schematically, the vibrating, but not flowed through by the medium measuring tube 10 is bent substantially symmetrically with respect to a vertical axis to the longitudinal axis L substantially symmetrical and thereby essentially has a single antinode, see. For example, this also mentioned above<patcit id="pcit0059" dnum="US20070119265A"><text>US-A 2007/0119265</text></patcit>. <patcit id="pcit0060" dnum="US20070119264A"><text>US-A 2007/0119264</text></patcit>. <patcit id="pcit0061" dnum="US6691583B"><text>US-B 66 91 583</text></patcit>, or <patcit id="pcit0062" dnum="US6840109B"><text>US-B 68 40 109</text></patcit>, Similarly, the counter-oscillator 20, as in<figref idref="f0003">Fig. 5b</figref> shown schematically, in the operation of the transducer also excited to bending vibrations, which are formed substantially coplanar, but substantially in phase opposition to the bending vibrations of the measuring tube 10. Thus, the measuring tube 10 and counteroscillator 20 oscillate in operation at least temporarily and / or proportionately laterally in a Nutzmode in which they execute together substantially coplanar bending vibrations in the imaginary primary vibration level XZ.

0033In the event that the medium flows in the pipeline and thus the mass flow <i>m</i> is different from zero, Coriolis forces are induced by means of the above-mentioned vibrating measuring tube 10 in the medium flowing therethrough. These in turn act on the measuring tube 10 and cause an additional, sensory detectable - but not shown here - deformation of the measuring tube 10 according to a natural second natural mode, which is superimposed on the excited Nutzmode substantially coplanar. Consequently, the measuring tube also oscillates in Coriolis mode substantially along the imaginary primary vibration plane XZ.

0034The instantaneous expression of the deformation of the measuring tube 10 is, esp. In terms of their amplitudes, also dependent on the instantaneous mass flow m. As a second mode of natural vibration, the so-called Coriolismode, as usual in such transducers, for example, the natural mode of the anti-symmetric<i>f2</i>-Eigenmodes, ie those with two antinodes and / or the natural mode of the anti-symmetric <i>f4</i>-Eigenmodes serve with four antinodes. According to one embodiment of the invention, measuring tube 10 and counter-oscillator 20 are further dimensioned so that the empty measuring tube 10 has a lowest natural natural frequency, f₁₀, which is greater than or equal to a lowest natural natural frequency, f 20, of the counter-oscillator 20. In particular, measuring tube 10 and counter-oscillator 20 are dimensioned so that the filled with water measuring tube 10 has a lowest natural natural frequency, f_{10 H2O}, which is at least equal to a lowest natural natural frequency, f₂₀, the backswing 20 is. According to a further embodiment of the invention is also provided to tune measuring tube 10 and counter-oscillator 20 with respect to their vibration characteristics to one another so that a lowest natural natural frequency, f₁₀. _H2O Measuring tube 10 then at least a 1.1 times a lowest natural natural frequency, f₂₀, the counter-oscillator 20 corresponds when it is completely filled with water. For a measuring tube made of titanium with a nominal diameter DN of about 55 mm, a length, L₁₀, of about 570 mm and a wall thickness of about 2.5 mm, a natural resonant frequency, f_{10, air}, of <i>f1</i>-Eigenmodes the empty measuring tube approximately at 550 Hz, while a natural resonant frequency, f_{10, H2O}, of <i>f1</i>-Eigenmodes of the water-filled measuring tube would be about 450 Hz.

0035According to a development of the invention, the measuring tube 10 also leads, esp. Also based on the in the <patcit id="pcit0063" dnum="US6840109B"><text>US-B 68 40 109</text></patcit> shown in operation, at least temporarily, esp. At the same time to the aforementioned bending vibrations, torsional vibrations about a with the longitudinal axis L or the aforementioned bending vibration axis substantially parallel Torsionsschwingungsachse. Torsional vibration axis, bending vibration axis as well as the longitudinal axis L may, as is quite common in such transducers, be substantially coincident. For the measuring tube 10 described above, for example, a lowest natural resonant frequency would result for the torsional vibrations in the range of about 750 Hz.

0036For generating mechanical oscillations of the measuring tube 10 - be it bending vibrations and / or torsional oscillations - the transducer further comprises a, in particular electrodynamic, excitation arrangement 40. This serves to inform by means of the operating and evaluation electronics inform a suitably conditioned electrical drive signal, eg with a regulated current and / or a regulated voltage, fed electrical excitation energy <i>e_exc</i> in a on the measuring tube 10, for example, pulse-shaped, clocked or harmonious, acting and this in the manner described above elastically deforming exciter force <i>F_exc</i> convert. The excitement<i>F_exc</i>can do this, as in <figref idref="f0002">Fig. 4</figref> shown schematically, bidirectionally or else unidirectionally formed and in the manner known in the art, for example by means of a current and / or voltage control circuit, in terms of their amplitude and, for example by means of a phase-locked loop, are set in terms of their frequency.

0037In particular, the excitation order, as is well customary in such transducers, further designed and arranged in the transducer that it acts substantially centrally on the measuring tube and / or at least selectively fixed along an imaginary central peripheral line of the measuring tube on the outside of this.

0038As energizing arrangement, for example, a simple differentially acting on measuring tube 10 and counteroscillator 20, electrodynamic immersion coil assembly with a counter-oscillator 20 mounted on the cylindrical excitation coil, which is traversed by a corresponding exciting current in operation, and with a at least partially immersed in the excitation coil permanent magnet armature of outside, esp. Centrally, is fixed to the measuring tube 10 serve. Alternatively, the exciter assembly 40 may be realized, for example, as an electromagnet or as a seismic exciter.

0039For detecting vibrations of the measuring tube 10 may be used, for example, in the manner known to those skilled in the art by means of an inlet side, spaced from the first coupling zone 11 # on the measuring tube 10 first vibration sensor 50A and by means of an outlet, of the second coupling zone 12 # spaced at the measuring tube 10 placed, esp. To the vibration sensor 50A substantially identical, the second vibration sensor 50B detects the movements of the measuring tube 10 and in a corresponding first and second sensor signal S.₁, P₂ being transformed. As sensors 50A, 50B, it is possible, for example, to use the oscillations relative to the counteroscillator, for example differentially measuring, electrodynamic velocity sensors or else electrodynamic displacement sensors or acceleration sensors. Instead of electrodynamic sensor arrangements or in addition to the same can also be used by means of resistive or piezoelectric strain gauges measuring or opto-electronic sensors for detecting the vibrations of the measuring tube 10.

0040According to a further embodiment of the invention, the exciter assembly 40, such as in <figref idref="f0002">Fig. 2 or Fig. 3</figref> shown schematically, so formed and arranged in the transducer so that it simultaneously, esp. Differentially, on measuring tube 10 and counter-oscillator 20 acts.

0041In the exemplary embodiment shown here, the exciter arrangement 40 for this purpose has at least one first exciter coil 41a, which is at least temporarily energized by the excitation current or an exciter subcurrent, fixed to a lever 41c connected to the measuring tube 10 and via this and an armature fixed externally to the counteroscillator 20 41b differentially on the measuring tube 10 and the counteroscillator 20 acts. This arrangement also has the advantage that, on the one hand, the counter-oscillator 20 and thus also the transducer housing 100 are kept small in cross-section and nevertheless the exciter coil 41a, esp. Also during assembly, is easily accessible. In addition, there is a further advantage of this embodiment of the exciter assembly 40 is that any used, esp. At nominal widths of about 50 mm is no longer negligible heavy, Coil beaker 41d are likewise fixable on the counteroscillator 20 and thus have practically no influence on the resonance frequencies of the measuring tube 10. However, it should be noted at this point that, if necessary, the excitation coil 41a can also be supported by the counteroscillator 20 and, accordingly, the armature 41b of the measuring tube 10. As an alternative or in addition to the differentially acting exciter arrangement 40, the sensor arrangement 50 can also be designed and arranged in the transducer so that the vibrations of the measuring tube 10 and counteroscillator 20 are detected differentially by it. the exciting coil 41a may also be supported by the counter-oscillator 20 and, accordingly, the armature 41b may be supported by the measuring tube 10. As an alternative or in addition to the differentially acting exciter arrangement 40, the sensor arrangement 50 can also be designed and arranged in the transducer so that the vibrations of the measuring tube 10 and counteroscillator 20 are detected differentially by it. the exciting coil 41a may also be supported by the counter-oscillator 20 and, accordingly, the armature 41b may be supported by the measuring tube 10. As an alternative or in addition to the differentially acting exciter arrangement 40, the sensor arrangement 50 can also be designed and arranged in the transducer so that the vibrations of the measuring tube 10 and counteroscillator 20 are detected differentially by it.

0042In the exemplary embodiment shown here, the sensor arrangement 50 comprises a sensor coil 51a fixed to the measuring tube 10. The sensor coil 51a is arranged as close as possible to an armature 51b fixed to the counteroscillator 20 and magnetically coupled therewith in such a way that a variable measuring voltage is induced in the sensor coil, the lateral relative movements between the measuring tube 10 and counteroscillator 20 changing by a relative distance between sensor coil and armature and / or a relative position of the sensor coil with respect to the armature changing rotational relative movements between the measuring tube 10 and counter-oscillator 20 is influenced. If necessary, however, the sensor coil 51a can also be fixed to the counter-oscillator 20 and, in a corresponding manner, the armature 51b coupled to it on the measuring tube 10.

0043According to a further embodiment of the invention is further provided to build vibration exciters and vibration sensors according to the same principle of action, esp. Essentially form each other identical in construction. Furthermore, it is also possible to fix coil and / or armature of excitation and / or sensor arrangement waiving a mediating lever each directly on the measuring tube or the counteroscillator.

0044According to a further embodiment of the invention, measuring tube 10, counteroscillator 20 and the attached sensor and exciter assemblies 40, 50 are further coordinated with respect to their mass distribution, that the thus formed, by means of the input and the outlet tube piece 11, 12 suspended inner part of the transducer has a center of gravity MS, which is at least within the measuring tube 10, but preferably as close as possible to the Meßrohrlängsachse L. In addition, the inner part is further formed so that it is aligned with the inlet pipe piece 11 and the outlet pipe piece 12 and at least partially within the measuring tube 10 lying first inertial main axis T.₁ having. As a result of the positioning of the center of mass MS of the inner part, esp. But also due to the above-described position of the first inertial main axis T.₁ the torsional vibrations and the bending vibrations of the measuring tube 10 can be mechanically decoupled from each other as far as possible at least in Nutzmode.

0045The inner part transducer is designed according to a further embodiment of the invention such that a first inertial main axis T₁ thereof substantially coincident with the upper longitudinal axis L. Furthermore, according to a further embodiment of the invention, the inner part of the transducer is designed such that a second inertial main axis T₂ of which substantially coincides with the above-mentioned center axis.

0046The formed by means of the measuring tube 10, the counter-oscillator 20, the inlet tube piece 11 and the Auslaßrohrstücks 12 inner part of the transducer is, as from a synopsis of <figref idref="f0001">Fig. 1</figref> and <figref idref="f0002">2</figref> can be seen, further supported in a selbiges inner part medium-tight and largely pressure-resistant enveloping transducer housing 30 vibrationally fixed at each of the coupling zones remote end of the inlet and outlet pipe section 11, 12. In the event that the transducer is releasably mounted with the pipe, the inlet pipe piece 11 and the outlet pipe piece 12 respectively a first and second flange 13, 14 are formed accordingly. The flanges 13, 14 can also be formed as an integral part of the converter housing 30 at the same time. If necessary, inlet and outlet pipe sections 11, 12 can also be connected directly to the pipeline, eg by means of welding or brazing.

0047For connecting the excitation arrangement as well as the sensor arrangement to the mentioned operating and evaluation electronics of the in-line measuring device further corresponding connection lines are provided, which are at least partially guided within the transducer housing. The leads may be at least partially as electrical, at least partially formed in an enclosed by electrical insulation wires, eg inform of "twisted pair" cables, ribbon cables and / or coaxial cables. Alternatively or in addition to this, the connection lines can also be formed, at least in sections, by means of strip conductors of a, in particular flexible, optionally painted circuit board.

0048According to a further embodiment of the invention comprises the transducer according to the invention, as well as from the synopsis of <figref idref="f0002">FIGS. 2</figref> and <figref idref="f0003">5a to 5d</figref> can be seen to further improve the measurement accuracy and based on the in the above-mentioned <patcit id="pcit0064" dnum="US20070186685A"><text>US-A 2007/0186685</text></patcit>. <patcit id="pcit0065" dnum="US20070119265A"><text>US-A 2007/0119265</text></patcit>. <patcit id="pcit0066" dnum="US20070119264A"><text>US-A 2007/0119264</text></patcit>. <patcit id="pcit0067" dnum="US6691583B"><text>US-B 66 91 583</text></patcit>, or <patcit id="pcit0068" dnum="US6840109B"><text>US-B 68 40 109</text></patcit> proposed transducer further comprises a coupled in the region of the first coupling zone with the inlet pipe section 11 and the measuring tube 10 first arm 15, the-as in <figref idref="f0002">Fig. 3a</figref> schematically illustrated - a lying in the region of the inlet pipe section 11 center of mass M₁₅ and in the region of the second coupling zone with the outlet pipe section 12 and the measuring tube 10 coupled second boom 16, the-as also in <figref idref="f0003">Fig. 5a</figref> schematically illustrated - a lying in the region of the Auslaßrohrstücks 12 center of gravity M₁₆ having. In other words, the two, in particular substantially identical, possibly even identical, cantilevers 15, 16 are arranged in the transducer so that the respective center of mass M₁₅, M₁₆ from the measuring tube 10, esp. Lying in the flight, is spaced. The two arms 15, 16 are therefore so far eccentric on inlet and outlet pipe and accordingly eccentrically mounted on measuring tube 10 and counter-oscillator 20. The mode of action of the inner part thus formed corresponds to that in the mentioned<patcit id="pcit0069" dnum="US20070186685A"><text>US-A 2007/0186685</text></patcit>. <patcit id="pcit0070" dnum="US20070119265A"><text>US-A 2007/0119265</text></patcit>. <patcit id="pcit0071" dnum="US20070119264A"><text>US-A 2007/0119264</text></patcit>. <patcit id="pcit0072" dnum="US6691583B"><text>US-B 66 91 583</text></patcit>, or <patcit id="pcit0073" dnum="US6840109B"><text>US-B 68 40 109</text></patcit> shown internal parts.

0049In order to enable a simple and cost-effective production of the boom and finally the transducer, each of the two arms 15, 16 may be formed, for example, substantially tubular or sleeve-shaped, so that it is practically pushed by means of a pushed onto the counteroscillator 20, esp. Metallic, sleeve can be formed, esp. Even if the counteroscillator 20 has already been connected to the measuring tube 10. According to a further development, each of the respective arms 15, 16 forming sleeves each have at least one annular groove, cf. also for this the mentioned ones<patcit id="pcit0074" dnum="US20070186685A"><text>US-A 2007/0186685</text></patcit>. <patcit id="pcit0075" dnum="US20070119264A"><text>US-A 2007/0119264</text></patcit> or <patcit id="pcit0076" dnum="US20070119265A"><text>US-A 2007/0119265</text></patcit>,

0050For the production of measuring tube, inlet and outlet tube piece, counteroscillator and optionally provided cantilevers, moreover, virtually any of the usual materials for such transducers, such as steel, titanium, tantalum, zirconium, etc., or corresponding combinations of these materials can be used. For example, the use of titanium for the measuring tube 10 and the inlet tube 11 and the outlet tube 12 has been found to be particularly suitable, for example, for reasons of cost savings, both for the counteroscillator 20 and the optionally provided boom 15, 16 and for the converter housing 30 the use of steel is quite beneficial.

0051As already mentioned, in transducers of the aforementioned type, esp. In those with a straight tube a particular problem is that the transducer not only natural vibration modes both in the imaginary primary vibration level XZ and in the orthogonal notional secondary vibration plane YZ Moreover, at least some of the vibration modes in the secondary vibration plane YZ may also have such a natural resonance frequency, which may be substantially equal to a natural resonance frequency of a corresponding vibration mode in the primary vibration plane XZ. Such mutually corresponding oscillation modes can also each have waveforms of the same order, ie in each case the same number of nodes.

0052Therefore, bearing the calculation, a first spring element 61 and a second spring element 62 are also provided in the transducer according to the invention. Each of the at least two, for example, substantially identical design, spring elements is - as well as in the<figref idref="f0004 f0005 f0006">Fig. 6a to 8b</figref> schematically illustrated - fixed with a respective measuring tube-side first end on the measuring tube 10 and with a respective counter-oscillating second end on the counter-oscillator 20, for example, in each case at the same distance from the center of the measuring tube. According to the invention, the spring elements are arranged in the transducer so that each of the two spring elements 61, 62 is anchored both from each of the two coupling zones 11 #, 12 # as well as from the excitation arrangement 40 at a distance with measuring tube and counteroscillator and thus from the two coupling zones 11 #. , 12 # and spaced from the exciter assembly 40 acts on measuring tube and counter-oscillator. Preferably, the first spring element 61 is at a distance from the second spring element 62 fixed to measuring tube and counteroscillator,

0053In particular, it is further provided, the spring elements 61, 62 each with the measuring tube side first end to form a respective substantially rigid and / or substantially backlash-free storage on the measuring tube and with the counteroscillator second end to form a respective substantially rigid and / or im essential play-free storage to fix the counter-oscillator.

0054With regard to the actual positioning within the transducer as well as the number of spring elements ultimately used, there are now various design options and variants, some of which will be explained in more detail below.

0055According to the invention, as well as in the <figref idref="f0004">FIGS. 6a</figref>. <figref idref="f0005">7a</figref> and <figref idref="f0006">8a</figref> shown schematically in each case, the first spring element in a lying between the first coupling zone 11 # and the at least one vibration exciter inlet side region fixed to measuring tube and counteroscillator. Further refinement of this refinement is provided for fixing the second spring element to a measuring tube and counteroscillator in an outlet-side region lying between the second coupling zone 12 # and the at least one vibration exciter.

0056According to a further embodiment of the invention is further provided, the spring element 61, 62, as well as from the synopsis of <figref idref="f0005">Fig. 7a and 7b</figref> can be seen so arranged in the transducer, that that first spring element 61 along a parallel to the longitudinal axis L extending imaginary lateral line of the measuring tube 10 fixed to selbigem, which also parallel to this imaginary side line of the measuring tube 10 along which the second spring element 62 with its meßrohrseitigen end fixed to the measuring tube is substantially diametrically opposite. In particular, in this case it is further provided that the two spring elements 61, 62 are also arranged point symmetrical with respect to a center of gravity of the measuring tube 10 or the aforementioned center of gravity MS of the transducer in selbigen. In other words, the measuring tube-side ends of the two spring elements 61, 62 should lie advantageously on a common imaginary diagonal of the transducer passing through the center of gravity; Similarly, then the counter-oscillator end of the two spring elements 61, 62 are on a common further, also passing through the center of gravity imaginary diagonal of the transducer. This arrangement of the spring elements has the advantage that not only very effective frequency shifts between resonant frequencies of corresponding vibration modes in the primary and secondary vibration level can be achieved, but also also in a very simple way an additional frequency shift between the resonant frequencies of the aforementioned torsional vibrations of the measuring tube and those of the lateral vibrations, in particular those in the primary vibration plane, can be realized without thereby significantly hindering the excitation of the torsional vibrations as such.

0057According to the invention, the at least two spring element 61, 62 are formed and arranged in the transducer that a lowest natural frequency of the above-mentioned first natural vibration mode is set smaller in the imaginary primary vibration level by means of the two spring elements, as a lowest natural frequency of the second natural Vibration modes in the imaginary secondary vibration plane. In particular, in this case, it is further provided to form the transducer so that a frequency difference between the lowest natural frequency of the first natural vibration mode and the lowest natural frequency of the second natural vibration mode greater than 50 Hz, especially greater than 100 Hz, is set.

0058Alternatively or in combination thereto, it is further provided according to the invention that each of the two spring elements 61, 62 has a spring rigidity, of which a respective bending vibrations of the measuring tube in the primary vibration level XZ inhibiting primary component is different from a bending vibrations of the measuring tube in the secondary Vibration level YZ inhibiting secondary component. In particular, it is provided that each of the two spring elements 61, 62 is formed and arranged in the transducer so that the primary component of the spring stiffness is in each case smaller than the associated secondary component.

0059The aforementioned difference between primary and associated secondary component can be achieved for the respective spring element, for example in a simple manner that - as for example from the synopsis of <figref idref="f0004">FIGS. 6a and b</figref> apparent or as in <figref idref="f0007">Fig. 9</figref> each of the spring elements each as an elongated body, such as a rod, a coil spring, a leaf spring or the like, formed and arranged in each case in the transducer, that it is in operation due to bending vibrations of the measuring tube 10th in the primary plane of vibration to a both respective spring element ends imaginarily connecting longitudinal axis is bent transversely in the manner of a clamped at both ends string.

0060According to a further advantageous embodiment, accordingly, each of the, in particular identical, spring elements are each formed by means of a, esp. Metallic, rod. The use of a metallic rod as a spring element has, apart from a comparatively simple, nevertheless very robust construction of the spring elements, at the same time very good spring action, in particular the advantage that in the production of standardized, in this respect also cost-effective mass product readily be used can.

0061Further, the spring elements are arranged according to a further embodiment of the invention in the transducer, that each of the elongated body designed, esp. Rod or rod-shaped, spring elements extending substantially in the radial direction of the measuring tube and / or counter-oscillator. Alternatively, it may well be advantageous, especially at significantly fluctuating operating temperature and concomitant, caused by thermally induced strains in the radial direction changes in the relative distance between the measuring tube and the counteroscillator, when selbiges rod-shaped spring element relative to the measuring tube 10 and its Longitudinal axis L inclined and / or slightly bent and thus radially slightly yielding.

0062According to another embodiment of the invention, the two spring elements are placed in the transducer so that each of the two spring elements is arranged in an imaginary extending through the inlet-side region and the outlet region straight cutting plane of the measuring tube. Alternatively or in addition, it is further provided that each of the two, for example, rod-shaped or rod-shaped, spring elements is mounted proportionately at imaginary intersections of the measuring tube with the imaginary secondary vibration level YZ. It is further provided that each of the two spring elements is mounted proportionately at imaginary intersections of the counter-oscillator with the secondary vibration plane YZ. In the case,

0063According to a further embodiment of the invention, the spring elements are further arranged in the transducer, that the first spring element is fixed at least in the vicinity of an inlet-side circumference of the measuring tube to the latter along which said first vibration sensor here on the inlet side - effectively detected movements of the measuring tube, and that second spring element is fixed at least in the vicinity of an outlet-side peripheral line of the measuring tube to the latter, along which the mentioned second vibration sensor - here outlet side - detected movements of the measuring tube effectively. Further optimizing this embodiment, the spring element are further arranged in the transducer, that the first spring element and said first vibration sensor are respectively fixed proportionally along at least the extent of the common inlet side circumference of the measuring tube to the latter, and that the second spring element and said second vibration sensor are each partially along at least the extent of the common outlet side peripheral line of the measuring tube fixed thereto , This is of particular advantage insofar as undesired measuring tube oscillations in the secondary oscillation plane are extremely effectively suppressed, at least at the respective vibration sensor, and can even be almost completely prevented in the case of rod-shaped or rod-shaped spring elements. As a result, in a very simple, but very effective way, coupling, for example also introduced from the outside into the transducer, In the secondary vibration plane, mechanical disturbances in the vibration signals supplied by the vibration sensors are almost completely and safely avoided. This also makes it possible, for example, to use such vibration sensors, which have a certain cross-sensitivity to vibrations within the secondary vibration plane, and which can be produced more cost-effectively because of their comparatively simpler construction to that extent.

0064According to a further embodiment, it is further provided to fix the spring elements along a in the primary vibration level biegeschwingendem measuring tube substantially non-distorting neutral fiber of the measuring tube to selbigem. For the case described above, that also the counteroscillator executes at least temporarily bending vibrations around the bending vibration axis during operation, it is further provided that the spring elements are fixed to the same along a substantially non-distorting in bending oscillating counteroscillator neutral fiber of the counteroscillator. The attachment of the spring elements along the neutral fibers of measuring tube and counter-oscillator can be achieved, for example,

0065Other examples of suitable structural embodiments of the spring elements and / or their arrangement relative to the primary and secondary vibration level are otherwise in the aforementioned <patcit id="pcit0077" dnum="US5291792A"><text>US-A 52 91 792</text></patcit> or <patcit id="pcit0078" dnum="US7077014B"><text>US-B 70 77 014</text></patcit> or in the <patcit id="pcit0079" dnum="US4823614A"><text>US-A 48 23 614</text></patcit> shown.

0066According to a development of the invention, the transducer comprises, as in the <figref idref="f0006">Fig. 8a</figref> schematically, further an additional third spring element 63 and a fourth spring element 64. The, for example, again substantially identical, spring elements are again arranged in the transducer so that each of the now four spring elements 61, 62, 63, 64 - as well as the synopsis of <figref idref="f0002">Fig. 2</figref> and <figref idref="f0006">Fig. 8a</figref> each of the coupling zones 11 #, 12 # as well as the exciter assembly 40 spaced at measuring tube 10 and counteroscillator 20 is fixed. In particular, the spring elements 61, 62, 63, 64 are further arranged in the transducer so that each of the four spring elements is also each spaced from each of the respective other three spring elements. In particular, the spring elements are arranged so that - as from the synopsis of<figref idref="f0006">Fig. 8a and 8b</figref> readily apparent - pairs spring elements together, here so the first and third spring element 61, 63 on the one hand and the second and fourth spring element 62, 64 on the other hand, in each case substantially diametrically opposed.

0067The parameters to be set for the actual implementation in detail for the required stiffness of the spring elements as well as their respective optimal positioning in the transducer can be adapted accordingly to the nominal diameter DN actually provided for the measuring tube 10 as well as the insertion length provided for the measuring tube , The transducer according to the invention is both for measuring tubes with rather smaller nominal sizes DN in the range of less than 40 mm and in particular for use in piping with a calibrator of more than 50 mm and, consequently, also for measuring tubes with nominal widths of substantially greater than 40 mm well suited.