Measuring transducer of the vibration type

Translation of description of equivalent WO 2009053344 A1

p0001description

p0002Transducer of vibration-type

p0003[0001] The invention relates to a, esp. For use in a Coriolis mass flow meter suitable, with at least one at least temporarily vibrating measuring tube for guiding medium to be measured, a counter-oscillator, the fixed transducer of vibration-type, forming a first coupling zone on the inlet side on the measuring tube is and is fixed to form a second coupling zone on the outlet on the measuring tube, an exciter assembly for driving at least the measuring tube and a sensor arrangement for detecting vibrations at least of the measuring tube. [0002] In the industrial measurement technology, esp. In connection with the control and monitoring of automated industrial processes, for the determination of characteristic process parameters, for example, a mass flow rate, a density, a viscosity, etc., from flowing in a pipeline media, for example by liquids and / or gases, are often, esp. designed as Coriolis mass flow meters, in-line measuring devices used, by means of a measuring transducer of vibration type and a connected thereto operating and evaluating, in the flowing medium forces, for example Coriolis forces induce and this derived a produce the at least one parameter corresponding measurement signal representing. Such in-line measuring devices with a measuring transducer of vibration type have long been known and have established themselves equally in industrial use. Examples of such transducers, esp. The use thereof in

p0004Coriolis mass flow meters, for example in EP-A 317 340, US-A 48 23 614, US-A 52 91 792, US-A 53 98 554, US-A 54 76 013, US-A are 56 02 345, US-A 56 91 485, US-A 57 96 010, US-A 57 96 012, US-A 59 45 609, US-A 59 79 246, US-B 63 97 685 , US-B 66 91 583, US-B 68 40 109, US-B 70 77 014, US-B 70 17 424, US-A 2007/0186685, US 2007/0119265 A, US- A 2007/0119264, WO-A 99 40 394, WO-A 01 02 816 or WO-A 00 14 485..

p0005[0003] Each of the transducer depicted therein at least comprises a substantially straight, in operation vibrating measuring tube for guiding the medium which communicates via a measuring tube on the inlet side einmündendes inlet pipe section and an outlet side einmündendes outlet tube to the pipeline.

p0006[0004] Further, each of the transducers shown a one-piece or multi-piece executed counter-oscillator, which is on the inlet side coupled to form a first coupling zone of the measuring tube and which is the outlet coupled to form a second coupling zone of the measuring tube and the proportionate at least during operation in each case includes at least also is vibrated. In the example in the US-A 52 91 792, US-A 57 96 010, US-A 59 45 609, US-B 70 77 014, US-A 2007/0119264, WO-A 01 02 816 or WO-a 99 40 394 transducer shown with a single, substantially straight flow tube are the latter and the counter-oscillator, as in conventional, industry-standard transducers quite common, mutually aligned substantially coaxially. In addition, the counter-oscillator is straight usually substantially tubular and substantially and also arranged in the measuring transducer, that the measuring tube is at least partially encased by the counter-oscillator and the measuring tube and counter-oscillators are aligned substantially coaxially with marketable measuring transducers of the above-mentioned type.

p0007[0005] A transducer of the kind in question further comprise a

p0008Excitation device, which usually imaginary, the measuring tube in operation, controlled by a suitably conditioned electrical drive signal, by means of at least one acting thereon electromechanical, especially electrodynamic, the vibration exciter to bending vibrations as possible predominantly or exclusively in a single -. To as primary oscillation plane designated - pipe excites vibration plane intersecting the two coupling zones imaginary. Furthermore exhibit such transducer, a sensor arrangement with, esp. Electro-dynamic vibration sensors for detecting at least punctual inlet-side and outlet-side oscillations of the measuring tube and for generating the mass flow rate influenced on electrical sensor signals.

p0009[0006] The exciter arrangement has at least one electrodynamic and / or differential acting on the measuring tube and counter-oscillator, vibrator, while the sensor assembly includes an inlet-side, usually likewise electrodynamic, oscillation sensor and a to substantially identical outlet vibration sensor. In mark current transducers with a single measuring tube and coupled thereto counteroscillator the vibration exciter is usually by means of an at least temporarily by a current flowing through it and at least temporarily traversed by a magnetic coil and a formed with the at least one coil interacting, esp. In this plunging, anchor, which is fixed according to the measuring tube. In addition, conventional transducers, the exciter arrangement is usually so constructed and placed in the measuring transducer that it acts centrally on the measuring tube substantially. Usually at least one vibration exciter and so far, the exciter mechanism is further, as for example in the in the US-A 57 96 010 US B 68 40 109, US-B 70 77 014 or US-B 70 17 424 shown proposed transducers, at least selectively outside fixed along an imaginary central circumferential line of the measuring tube at this, while for example in the US-a 48 23 614, the exciter mechanism by means of two is not formed at this fixed vibration exciter in the center of the measuring tube.

p0010[0007] For most transducers of the type described are the

p0011Vibration sensors of the sensor arrangement, as already indicated, designed according to the same principle as the aforementioned vibration exciter. Accordingly, the vibration sensors such a sensor arrangement are mostly respectively by at least one usually at the counter-oscillator fixed, at least temporarily traversed by a current and at least temporarily permeated by a magnetic coil and a fixed on the measuring tube, formed with at least one coil cooperating anchor. Each of the aforementioned coils is additionally connected by at least one pair of electrical leads to the aforementioned operating and evaluating the in-line measuring device. The leads are usually conducted on a short way from the coils of the equivalent to the transducer housing. In addition to measures for sensing vibrations of the measuring tube vibration sensors, the measuring transducer, such as, inter alia, in EP-A 831 306, US-A 57 36 653, US-A 53 81 697 or WO-A 01/02 816 proposed another, esp. the detection of rather secondary measured variables, such as temperature, acceleration, strain, stress etc., serving at any rate by means of the measuring tube, the counter-oscillator and the thereto respectively attached excitation and sensor assembly formed inner part, or also in the nearby arranged have sensors.

p0012[0008] Finally, each of the in US-A 52 91 792, US-A 59 45 609, US-B 70 77 014, US-A 2007/0119264, WO-A 01 02 816 or the WO-a 99 40 394 shown transducer a, esp. directly at the inlet pipe section and the outlet tube fixed, the measuring tube with coupled thereto counter-oscillator and the place designated driver and sensor arrangement enclosing additional converter housing, whereas for example in the in the US-a 48 23 614 illustrated transducer, the transducer housing is virtually formed by the counter-oscillator itself, or, in other words, the transducer housing and counter-oscillator one and the same unit are.

p0013[0009] An advantage of transducers with straight measuring tube is compared to those with a bent measuring tube as that which the measuring tube in virtually any position, esp. After an in-line cleaning carried out, emptied with high security without residue itself. Furthermore, such measuring tubes as compared to a bent measuring tube are much simpler and therefore more cost-effective and cause the operating mostly a lower pressure drop.

p0014[0010] A straight measuring tube causes known in the medium flowing through Coriolis forces when selbiges measuring tube to bending vibrations in the primary vibration level according to a first mode shape - the so-called drive or useful fashion - is encouraged. proposed in conventional measuring transducers of the above-mentioned type, for example, such as described in US-A 52 91 792, US-B 68 40 109, US-B 70 77 014 or US-B 70 17 424, in which the measuring tube wanted mode is left mainly oscillate in the imaginary primary vibration level, these Coriolis forces in turn lead to that selfsame bending oscillations in the wanted mode coplanar - therefore also fully introduced in the primary vibration plane - bending vibrations in a second natural oscillation mode of mostly higher order, but in any case other symmetry properties - be -überlagert called Coriolis or measuring mode. Due to the bending vibrations in the Coriolis mode, the inlet and outlet detected by the sensor array to a vibration also dependent on mass flow, measurable phase difference.

p0015[0011] Typically, the flow tubes of such transducers esp. Those that are used in Coriolis mass flow meters, in the wanted mode on an instantaneous resonance frequency of the first natural oscillation mode, esp. In constant oscillation amplitude controlled stimulated. Since this resonance frequency is also dependent on the instantaneous density of the medium in particular, in addition to the mass flow rate at least also the density of flowing media can be measured directly through common Coriolis mass flow meter.

p0016[0012] A particular problem the above-described transducer is straight measuring tube, such as in the US-A 52 91 792 or US-B 70 77 014 discussed, however, is that they not only have the aforementioned natural vibration modes, in which the measuring tube flexural vibrations in said primary oscillation plane running, but also those natural vibration mode in which the measuring tube bending vibrations in another imaginary, the primary vibration plane substantially orthogonal nevertheless the two coupling zones can perform imaginary intersecting secondary vibration level, and that those oscillation modes naturally have in the secondary vibration level without the taking of specific measures approximately the same resonant frequency as the each corresponding vibration mode in the primary plane of oscillation. In other words, any measurement inaccuracies can case of measuring transducers of the type in question with a straight measuring tube result from that in addition to the desired excited wanted mode in the primary vibration plane unwanted and far disturbing vibrations in the secondary vibration level occur, very close to the resonant frequencies of the useful mode lie. Similarly, as the useful mode in the primary level of vibration and the excited undesirably equifrequency vibration mode would then in the secondary vibration plane coplanar to induced by Coriolis forces corresponding conditional additional vibration modes. Causes for such interference can in the connected piping or the flowing medium to be outgoing, mostly broadband noise for example vibrations.

p0017[0013] As a result of in practice almost inevitable cross-sensitivities of the vibration sensors to vibrations in the secondary vibration level, this results in that the items delivered under such circumstances sensor signals proportionally both vibrations of the measuring tube in the primary vibration level and corresponding oscillations of the measuring tube secondary vibration level in a significant for the measurement precision measurements reflect an assignment of the signal components corresponding to the primary and secondary vibration level is practically not possible due to the substantially same frequencies corresponding vibrations.

p0018[0014] Moreover, in a sufficiently strong mechanical coupling of the two oscillation modes vibration planes also a transfer of Vibrational energy - spontaneously or periodically - possible from the primary to the secondary vibration level or conversely from the secondary to the primary level of vibration. Consequently, the sensor signals can comprise, for example one for the signal processing as well as for the sensor signals based on the vibration control quite harmful characteristic beating. Furthermore, oscillation movements in the secondary vibration level, whether they are caused by external disturbances directly or through the aforementioned energy transfer from the primary to the secondary vibration plane excited indirectly, cause the sensor signals may at times excessive signal level, with the result that the sensor signals receiving and processing input amplifier must be correspondingly dimensioned consuming and therefore are comparatively expensive.

p0019[0015] In order to suppress such were performing in the secondary vibration level, overall very damaging vibrations, it is common, effective for these oscillations stiffness of the measuring tube opposite one for oscillations in the primary vibration level effective stiffness of the flow tube at increasing substantially constant effective masses and thus effectively from each other to separate resonant frequencies of mutually corresponding vibrational modes of the primary and secondary vibration level. Typically, this frequency distances of more than 30 Hz will be sought.

p0020[0016] In the in the US-A 56 02 345 for this purpose is, for example,

p0021Using one and the outlet to the respective coupling zones at the respective measuring tube additionally attached in the immediate vicinity, proposed designed as flat webs spring elements. As a further possibility of separation of the vibration modes in the primary plane of oscillation of the corresponding oscillation modes in the

p0022Secondary vibration level is also shown in US-A 52 91 792nd When the transducer is proposed there for the oscillations in the secondary vibration level effective stiffness of the measuring tube increased by the fact that the measuring tube with a correspondingly acting as extending arranged in its center substantially in a radial direction to the measuring tube and the counter-oscillator in the measuring transducer, here U-shaped, stiffening spring formed spring element is acted upon the the stiffness measuring tube for Coriolis in the primary vibration level not appreciably affected. This can be achieved in that the oscillation frequency of the oscillations in the wanted mode sufficiently strongly stands out from the frequency of unwanted, so disturbing vibrations and thus the influence of such disturbing vibrations is largely suppressed.

p0023[0017] A disadvantage of such a centrally acting, rather scattered on the measuring tube attacking stiffening spring has 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, accompanied with the above-described disadvantages. Moreover, a such central, ie local maximum vibration amplitude acting stiffening spring, according to mechanically stable and accordingly must be designed vibration-resistant. On the other hand, but also the measures proposed in the US-A 56 02 345 webs are to be fixed only with comparatively high expense and adjust, esp., Even the application of this principle to a single measuring tube having arranged coaxial to this, the tubular counter-oscillator.

p0024[0018] An object of the invention is, therefore, with at least one temporarily vibrating measuring tube and a single and the outlet on the measuring tube fixed counter-oscillator to improve transducer of the aforementioned type so that an even more efficient as compared to the solutions presented separation of the resonance frequencies of the vibration modes in the primary and secondary vibration level can be achieved. This in particular also with respect to at least the aforementioned webs comparable or lower production costs. [0019] To achieve the object, the invention resides in a measuring transducer of vibration-type for a flowing in a pipeline medium, which transducer a at least temporarily vibrating measuring tube for guiding medium to be measured, a counter-oscillator, which fixes to form a first coupling zone on the inlet side on the measuring tube is and which is fixed to form a second coupling zone outlet side to the measuring tube, a, esp. substantially centrally acting on the flow tube and / or at least pointwise along an imaginary mid-circumferential line of the measuring tube externally fixed thereto, exciter arrangement for driving at least the measuring tube, and a sensor system for detecting vibrations at least of the measuring tube, wherein the measuring tube during operation rata bending vibrations performs at least temporarily and / or at least about an imaginary bending oscillation axis connecting the two coupling zones imaginary together. The transducer according to the invention further comprises a first spring element and a second spring element, wherein each of the at least two spring elements of both of each of the two coupling zones and the exciter arrangement spaced on the measuring tube and the counter-oscillator is fixed.

p0025[0020] In addition, the invention comprises a, for example, as

p0026Coriolis mass flowmeter, densitometer, viscometer or the like formed, in-line measuring device for measuring and / or monitoring at least one parameter, for example, a mass river a density and / or viscosity of flowing in a pipeline, the medium in which in-line measuring device is a transducer of the above type use.

p0027[0021] The transducer is in particular also designed such that it comprises at least a first natural vibration mode, in which at least the measuring tube bending vibrations can perform in an imaginary primary vibration plane. In addition, the transducer in the other is designed such that it has a second natural vibration mode in which at least the measuring tube flexural vibrations in an imaginary to the imaginary Primary vibration plane can carry substantially orthogonal secondary vibration level. This aspect of the transducer according to the invention further, it is provided that the measuring tube during operation by means of the exciter mechanism is at least temporarily excited such that it at least partially, especially. Predominantly or exclusively, oscillates in the imaginary primary vibration plane.

p0028[0022] According to a first embodiment of the invention it is provided that a lowest natural frequency of the first natural mode of oscillation is set to be smaller by means of the two spring elements, as a lowest natural frequency of the second natural mode of oscillation. This embodiment of the invention further, the spring elements are further constructed and arranged in the measuring transducer, that a frequency spacing between the lowest natural frequency of the first natural oscillation mode and the lowest natural frequency of the second natural mode of oscillation is greater than 50 Hz esp. Greater than 100 Hz, is set.

p0029[0023] According to a second aspect of the invention, each of the two spring elements have a spring stiffness of the respective bending vibrations of the measuring tube in the primary plane of oscillation inhibiting primary component is different from a bending oscillations of the measuring tube in the secondary vibration level inhibitory secondary component. This embodiment of the invention further, each of the two spring elements is further constructed and arranged in the measuring transducer, that the primary component of its spring rigidity is each smaller than the associated secondary component.

p0030[0024] In a third embodiment of the invention is further provided that each of the two spring elements is mounted on a pro rata imaginary intersections of the measuring tube with the secondary vibration level. Alternatively or in addition to each of the two spring elements is further supported proportionately to imaginary intersections of the counter-oscillator with the secondary vibration level.

p0031[0025] In a fourth embodiment of the invention comprises Exciter arrangement at least one, esp. Single and / or formed by a coil, vibration exciter.

p0032[0026] In a fifth embodiment of the invention comprises

p0033Exciter arrangement at least one, esp. Single and / or formed by a coil, vibration exciter and is additionally provided that the first spring element, is fixed in a between the first coupling zone and the at least one vibration exciter lying inlet-side area of ​​the measuring tube and counter-oscillator. This embodiment of the invention further, it is additionally provided that the first spring element spaced from the second spring element is fixed to the measuring tube and counter-oscillator. In addition to it, according to one embodiment of the invention further provided that the second spring element is fixed respectively in between the second coupling zone and the at least one vibration exciter lying outlet area of ​​the measuring tube and counter-oscillator. In addition to it, according to one embodiment of the invention additionally provided that the two spring elements are arranged in an imaginary plane passing through the inlet-side area and the outlet area straight section plane of the measuring tube in the measuring transducer.

p0034[0027] In a sixth embodiment of the invention it is provided that the two spring elements are point-symmetrical with respect to a center of gravity of the measuring tube arranged in the measuring transducer.

p0035[0028] In a seventh embodiment of the invention provides that the exciter mechanism least comprises a coil. This embodiment of the invention is a further development additionally provided that the at least one coil of the exciter mechanism with the counter-oscillator mechanically connected, esp. Rigidly coupled, is.

p0036[0029] In an eighth embodiment of the invention comprises

p0037Sensor arrangement an inlet-side, esp. Formed by a coil, the first vibration sensor and an outlet, esp. By means of a coil formed, second oscillation sensor. This embodiment of the invention further, it is additionally provided that the first spring element and the first oscillation sensor are fixed proportionately along at least one common inlet-side circumferential line of the measuring tube on the latter, and in that the second spring element and the second oscillation sensor are fixed proportionately along at least one common outlet-circumferential line of the measuring tube on the latter.

p0038[0030] In a ninth embodiment of the invention, the exciter arrangement has at least temporarily fed in the operation of an electric drive signal.

p0039[0031] In a tenth embodiment of the invention, the transducer comprises a transducer housing.

p0040[0032] In an eleventh embodiment of the invention it is provided that measuring tube and the counter-oscillator to each other are aligned substantially coaxially.

p0041[0033] In a twelfth embodiment of the invention provides that the measuring tube is at least partially encased by the counter-oscillator.

p0042[0034] In a thirteenth embodiment of the invention it is provided that the counter-oscillator is substantially tubular.

p0043[0035] In a fourteenth embodiment of the invention it is provided that the counter-oscillator is substantially straight.

p0044[0036] In a fifteenth embodiment of the invention, the measuring tube is essentially straight. This embodiment of the invention is a further development additionally provided that also the counter-oscillator in operation executes at least at times, bending oscillations about the bending oscillation axis, and that the spring elements along at biegeschwingendem counteroscillator not distorting essentially neutral axis of the counter-oscillator are fixed on that. Alternatively or in addition to this development of the invention it is further provided that the measuring tube during operation, at least at times, torsional oscillations about a bending oscillation with the axis substantially parallel, esp. Coincident, performs Torsionsschwingungsachse.

p0045[0037] According to a sixteenth embodiment of the invention, the measuring tube extends with an essentially constant, esp. A circular ring, Cross-section between the two coupling zones.

p0046[0038] In a seventeenth embodiment of the invention, the measuring tube is substantially cylindrical in shape.

p0047[0039] In an eighteenth embodiment of the invention are the

p0048Spring elements each with a meßrohrseitigen first end, esp. To form a respective rigid and / or play-free support, on the measuring tube and with a against schwinger side second end, esp. To form a respective rigid and / or play-free support, fixed on the counter-oscillator.

p0049[0040] In a nineteenth embodiment of the invention, each of the esp. Identical, spring elements respectively by a, esp. Metallic and / or arranged in a radial direction to the measuring tube and / or counter-oscillators ranging in transducer, formed rod.

p0050[0041] In a twentieth embodiment of the invention, the transducer further comprises a third spring element and a fourth resilient element, wherein each of the four spring elements of the coupling zones and the excitation arrangement is fixed to the measuring tube and spaced counter-oscillator. This embodiment of the invention further, it is additionally provided that each of the four, in particular. Identical, spring elements are each spaced from each of the respective other three spring elements. According to another embodiment of the invention is further provided that in pairs associated inlet-side spring elements are placed diametrically opposite to the measuring tube each substantially each other and wherein pairs belong together outlet-spring elements are placed diametrically each substantially opposite one another on the measuring tube.

p0051[0042] According to a twenty-first embodiment of the invention, the measuring tube communicates via an inlet side einmündendes inlet pipe section and an outlet side einmündendes outlet tube to the pipeline. This embodiment of the invention further, it is additionally provided that the measuring transducer further includes a fixed at the inlet pipe section and the outlet tube converter housing.

p0052[0043] A basic idea of ​​the invention is, inter alia, the frequency separation use those spring elements instead only centrally on the measuring tube acting spring elements, the away attack both from the center and from the aforementioned coupling zones and so effectively suppress addition symmetrical and asymmetrical interference. This has the advantage that as well as disorders of mostly asymmetrically formed Meßmodes, for example as a result of one-sided at is put into the pipe in-line meter attacking and / or wobbling movements of the in-line measuring about one of its principal axes of inertia causing time-varying forces, can be suppressed to a very simple manner very effective. In addition, the oscillation axis is clearly defined and kept largely stationary even with possible disturbances from the outside through the Federelmente.

p0053[0044] A particularly effective frequency separation can be, for example, by the use of substantially bar-shaped or rod-shaped achieve spring elements which are arranged in the measuring transducer, that they extend substantially in the secondary vibration level. A relative movement between Tilgerrohr and measuring tube to wanted and Coriolis in the primary vibration plane perpendicular thus practically blocked. This, especially then when the same spring elements are arranged in the measuring transducer, that they extend substantially radially to the measuring tube and / or the counter-oscillator. In addition, rod-shaped spring elements, esp. In comparison to the mentioned ends fixed to the measuring tube webs, are inexpensively manufactured and assembled, and whose mode of action compared to conventionally used spring elements is much more efficient.

p0054[0045] In the event that the spring elements are so arranged in the measuring transducer, characterized in that each of which directly acts on a circumferential line of the measuring tube along which also the respective vibration sensor is placed, can at least there Relative movements between measuring tube and the counter-oscillator to be almost completely excluded. This leads to the further advantage that acting from the outside in the secondary direction of vibration disturbances at the vibration sensor, no call value Strösignal can produce more even if this, a certain

p0055Cross sensitivity would have in this direction of oscillation. [0046] The invention and advantageous embodiments thereof will be explained with reference to an embodiment, the in the

p0056Figures of the drawing is shown; the same parts are provided in the figures for the rest the same reference numerals. If the

p0057Clarity is useful, is dispensed already mentioned reference characters in the following figures. In individual are in: [0047] Figure 1 is a shown in a pipe insertable in-line measuring device for measuring at least one parameter of a run in the pipeline medium, [0048] FIG 2 is cut in a side view of an exemplary embodiment of a for.. In-line measuring device of Fig. 1 suitable transducers from

p0058Vibration type shown with a measuring tube and a counter-oscillator and end-side booms,

p0059[0049] FIG. 3, the transducer of Fig. 2 shown in a cross section, [0050] FIG. 4 of the transducer of Fig. 2 in a different cross-section with a

p0060Spring element shown

p0061[0051] FIGS. 5 schematically bending lines of the measuring tube and the [0052] a through d counter-oscillator, each oscillating in a lateral

p0062Flexural mode in a primary plane of vibration

p0063Transducer, shown, [0053] FIGS. 6a, b show a variant of a transducer according to FIG. 2 with two spring elements shown in two different cut views, [0054] FIGS. 7a, b cut in two different views of another

p0064Variant shown for a transducer according to FIG. 2 with two spring elements, [0055] FIGS. 8a, b cut in two different views of another

p0065Variant for a transducer according to FIG. 2 with four spring elements shown, and [0056] FIG. 9 schematically shows a section of a transducer according to FIG. 2 with a spring element attached to the measuring tube and counter-oscillator. . [0057] FIG 1 is a in a - insertable pipe, for example, as a Coriolis mass flowmeter, densitometer, viscometer or the like formed, shown in-line measuring device, the measuring and / or monitoring at least one parameter - not shown here , for example, a mass flow rate, a density, a viscosity, etc., of a flowing medium in the pipeline serves. The in-line measuring device includes for one to a 200 housed in a corresponding electronics housing - not shown here - operating and evaluating the in-line measuring device electrically connected transducer of vibration-type, which is passed through the holding corresponding to the medium to be measured ,

p0066[0058] In FIGS. 2 to 4 is a concrete example with reference to

p0067Embodiment of the basic structure of such a transducer of vibration type schematically shown in various sectional views. In addition, the basic mechanical construction and its mode of operation of the transducer exemplarily shown with which the in US-A 2007/0119265, US 2007/0119264 A, US-B 66 91 583, US-B 68 40 109 are shown transducers comparable. Further embodiments and embodiments of the transducer according to the invention as well as details of which are also shown in FIGS. 6a, 6b, 7a, 7b, 8a, 8b and 9 are shown.

p0068[0059] The transducer is used to generate mechanical in a medium flowing through the reaction forces, eg mass Coriolis forces, density-dependent inertial forces and / or viscosity-dependent frictional forces which react measurably, especially. By sensor, react on the transducer. Derived from these reaction forces can be measured as in the known to the expert manner as a mass flow m, a density p and / or a viscosity η of the medium. For guiding the medium transducer comprises at least one - in the embodiment shown here, a single, essentially straight - tube 10 which vibrate during operation, and thereby, a static rest position is to oscillating, repeatedly elastically deformed with the transducer at least one first having natural vibration mode, in which at least the measuring tube bending vibrations can perform in an imaginary primary vibration plane XZ. This imaginary primary vibration plane XZ otherwise corresponds practically also the plane of FIG 5a -. 5d. In addition to the first natural vibration mode in the imaginary primary vibration plane XZ of the transducer also has naturally also includes at least a second natural vibration mode, in which at least the measuring tube bending vibrations in an imaginary, the imaginary primary vibration plane XZ substantially orthogonal secondary vibration YZ plane can carry.

p0069here substantially straight and substantially parallel to the measuring tube 10 extending - - counter-oscillator 20 is provided [0060] In order to minimize forces acting on the measuring tube 10 interference as well as to reduce the part of the transducer to the connected pipeline emitted vibration energy is in the measuring transducer further. This is, as also shown in Figure 2, to form a -. Defining practically an inlet end of the measuring tube 10 - first coupling zone 11 # on the inlet side and to form a - defining practically an outlet end of the measuring tube 10 - second coupling zone 12 # on the outlet respectively on the measuring tube 10 is fixed. The counter-oscillator 20 can Röhr - or be designed box-shaped and, for example, connected at the inlet end and the outlet end of the tube 10, that it is quite common, aligned as with such measuring transducers substantially coaxial with the measuring tube 10 and thus the tube 10 from the counter-oscillator 20 is at least partially sheathed. It may also be advantageous if the counter-oscillator 20 is made much heavier than the flow tube 10th

p0070[0061] the measuring tube 10 is to flow therethrough allowing the medium to be measured via an inlet side einmündendes in the first coupling zone inlet tube piece 11 and an outlet side einmündendes in the second coupling zone, esp. To the inlet tube piece 11 essentially identical, outlet tube 12 according to the medium increases or laxative - not shown here - pipeline connected. Inlet tube piece 11 and outlet tube 12 are being executed in the illustrated embodiment substantially and another, to the measuring tube 10 and to the coupling zones practically joined imaginary longitudinal axis L aligned. In an advantageous manner, measuring tube 10, inlet and outlet tube 11, 12 made in one piece, so that for their preparation as can serve a single tubular semifinished. Instead, that the measuring tube 10, inlet tube piece 11 and outlet tube 12 are each formed by segments of a single, one-piece tube, these semi-finished products can be prepared, if necessary, but also by means of single, subsequently joined together, eg welded together.

p0071[0062] According to one embodiment of the invention the flow tube is also designed such that it extends between the two coupling zones having substantially constant, especially, circular ring-shaped, extends in cross section. In particular, it is further provided that the measuring tube 10 is substantially cylindrical in shape.

p0072[0063] In operation of the transducer, the measuring tube 10 - as already mentioned several times - at least temporarily to lateral bending oscillations in the imaginary primary vibration plane XZ, especially so excited in the region of a natural resonance frequency of a corresponding natural oscillation mode that it was in this. so-called useful mode at least partially, especially. mostly, bends out according to a natural first mode shape. The bending oscillations in the useful mode are substantially transverse to a longitudinal axis L with the substantially parallel, esp. Coinciding, flexural oscillation axis aligned that the two coupling zones 11 #, 12 # imaginary together. According to one embodiment of the invention is hereby further provided that the measuring tube is at least temporarily excited during operation by means of the exciter mechanism such that it oscillates predominantly or exclusively in the imaginary primary vibration plane.

p0073[0064] In a further embodiment of the invention, the measuring tube 10 is In this case, an oscillation frequency, f_exc, Suggested that the closely corresponding to a natural resonance frequency of the so-called / 7-eigenmode of the measuring tube 10, so a symmetric eigenmode in which, as in FIGS. 5b to 5d schematically shown, the vibrating, but not by the medium through which flow tube 10 with respect to a plane perpendicular to the longitudinal axis L of the center axis is bent substantially symmetrical, thereby substantially having a single oscillation antinode. See this, for example, above-mentioned US-A 2007 / 0119265, US-A 2007/0119264, US-B 66 91 583, or US-B 68 40 109. Similarly, also the counter-oscillator 20, as shown in FIG. 5b schematically, also excited during operation of the transducer to bending vibrations in the are substantially coplanar, but substantially opposite phase is formed at the bending vibrations of the measuring tube 10th Thus oscillating measuring tube 10 and counter-oscillator 20 in operation so at least temporarily and / or partially laterally in a wanted mode, in which they run together substantially coplanar bending oscillations in the imaginary primary vibration plane XZ.

p0074[0065] In the event that the medium flowing in the pipeline and thus the mass flow m is different from zero, are induced by the vibrating in the manner described above the measuring tube 10 in the medium flowing through the Coriolis forces. These in turn act on the measuring tube 10 and so cause an additional, perceptible - but not shown here - deformation of the measuring tube 10 in accordance with a natural second natural oscillation mode that is superimposed on the excited wanted mode essentially coplanar. Consequently, the measuring tube oscillates in the Coriolis mode substantially along the imaginary primary oscillation plane XZ.

p0075[0066] The instantaneous character of the deformation of the measuring tube 10 is, esp. With regard to their amplitudes, and the instantaneous mass flow m. As a second mode shape, the so-called Coriolis mode, as in such transducers usual, for example, the natural vibration shape of the anti-symmetric / SP-eigenmode, ie those with two antinodes and / or the natural oscillation mode of the anti-symmetric / ^ - serve eigenmode having four antinodes. According to one embodiment of the invention, the measuring tube 10 and counter-oscillator 20 are further so dimensioned that the empty tube 10, a lowest natural eigenfrequency, f₁₀, Which is greater than or approximately equal to a lowest natural eigenfrequency, f 20, of the counter-oscillator 20. In particular, the measuring tube 10 and counter-oscillator 20 are dimensioned in such a way that the filled with water tube 10, a lowest natural eigenfrequency, f-io_{, H2}O_> comprises at least equal to a lowest natural eigenfrequency, f₂o, the counter-oscillator 20. According to another embodiment of the invention is further provided coordinate measuring tube 10 and counter-oscillator 20 to one another in terms of their vibration characteristics that a lowest natural eigenfrequency, f_{10, H2}o measuring tube 10 and then at least one 1, 1 times a lowest natural eigenfrequency, f₂₀, The counter-oscillator 20 corresponds to when it is completely filled with water. With 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 would have a natural resonant frequency, f_{10, air}, of / 7-eigenmode of the empty measuring tube are approximately at 550 Hz, while a natural resonance frequency, f_{10, H2}o. of / 7-eigenmode of the measuring tube filled with water about 450 Hz would be. According to a development of the invention, leads the measuring tube 10 also, esp. In accordance with the transducer shown in US-B 68 40 109, in operation, at least at times, especially. The same time as the aforementioned bending vibrations, torsional oscillations about a with the longitudinal axis L or the above-mentioned flexural vibration axis of substantially parallel Torsionsschwingungsachse. Torsionsschwingungsachse, flexural oscillation axis as well as the longitudinal axis L, as in such transducers is quite common, be substantially coincident. For the measuring tube 10 described above, for example, would a lowest natural resonance frequency of the torsional oscillations in give the range of about 750 Hz.

p0076[0068] For producing mechanical oscillations of the measuring tube 10 - be they bending oscillations and / or torsional oscillations - includes the transducer further an, especially electrodynamic, exciter mechanism 40. This serves a means of operating and evaluation electronics inform a suitably conditioned. electrical driving signal, for example with a regulated current and / or a regulated voltage, applied electrical excitation energy e_θxc \ N one on the measuring tube 10, for example, pulsed, pulsed or harmonic, acting and this in the manner elastically deforming exciting force F_exc convert. The exciter force F_eΛ,_c can in this case, as shown in Fig. 4 schematically, bidirectional, or but also formed unidirectionally be and in the manner known to the expert, for example by means of a current and / or voltage regulating circuit as regards their amplitude and, for example, by means of a phase locked loop, with respect to their frequency can be set.

p0077as with such measuring transducers [0069] In particular, the Erregranordnung, quite common, further formed and arranged in the measuring transducer, that it acts essentially centrally on the measuring tube and / or at least externally fixed at certain points along an imaginary mid-circumferential line of the measuring tube of this is ,

p0078[0070] As a excitation system as a simple differentially on the measuring tube 10 and counter-oscillator 20 acting, electrodynamic moving coil arrangement with a fastened to the counter-oscillator 20 cylindrical excitation coil which is flowed through the operation of a corresponding excitation current, and with a in the excitation coil at least partially immersed permanently magnetic armature which, especially from the outside. center, is fixed on the measuring tube 10, are used. Alternatively, can be implemented 40 as well as an electromagnet or as a seismic exciter, the exciter mechanism.

p0079[0071] For detecting oscillations of the measuring tube 10 can, for example, a conventional transducer for such sensor arrangement may be used in the manner known to the expert inlet side by means of a, of the first coupling zone 11 # spaced on the measuring tube 10 placed first vibration sensor 5oA and by means of an outlet side, of the second coupling zone 12 # spaced placed on the measuring tube 10, esp. the vibration sensor 5oA substantially identical, the second vibration sensor 5OB detects the movements of the measuring tube 10 and in a corresponding first or second sensor signal S₁, S₂ being transformed. As sensors 5oA, 5OB eg eg differentially measuring, electrodynamic velocity sensors or electrodynamic path sensors or acceleration sensors, the vibrations relative to the counter-oscillators can be used. Instead of electrodynamic sensor arrangements or in supplementation thereof may serve for detecting the oscillations of the measuring tube 10 also by means of resistive or piezoelectric strain gauges measured or optoelectronic sensors.

p0080be [0072] In a further embodiment of the invention, the exciter arrangement 2 or FIG. 3 is 40, such as in Fig. schematically illustrated, designed and arranged in the measuring transducer, the operation to simultaneously, esp. differentially, on the measuring tube 10 and counter-oscillator 20 acts.

p0081[0073] In the example shown here, the exciter arrangement 40 to at least one at least intermittently flowed through the excitation current or exciter current component during operation first exciter coil 41, which is fixed to a part connected to the measuring tube 10 lever 41c and on this and on the external counter-oscillator 20 fixed armature 41b differentially on the measuring tube 10 and the counter-oscillator 20 acts. This arrangement has inter alia the advantage that one part of the counter-oscillator 20, and thus also the transducer housing 100 in cross-section is kept small while the exciter coil 41, esp. While installing, is easily accessible. Moreover, another advantage of this embodiment of the exciter arrangement is 40 the fact that possibly used, esp. In nominal diameters of over 50 mm no longer negligible heavy, coil cups 41d also the counter-oscillator 20 can be fixed and thus practically no influence on have the resonance frequencies of the measuring tube 10th It should be noted at this point that if necessary, the exciter coil 41 and the counter 20 and, accordingly, the armature 41 b by the measuring tube 10 can be held. Alternatively or in addition to the differentially acting excitation device 40 can also be the sensor array 50 to be designed and arranged in the measuring transducer that the vibrations of the measuring tube 10 and counter-oscillator 20 are differentially detected by them.

p0082[0074] In the embodiment shown here, the sensor assembly 50 includes a fixed on the measuring tube 10 sensor coil 51a. The sensor coil 51 is positioned as close as possible to a fixed on the counter-oscillator 20 armature 51 b and so magnetically coupled with this, that in the sensor coil a variable measurement voltage is induced that changing by a relative distance between the sensor coil and armature lateral relative movements between measuring tube 10 and counter-oscillator is influenced 20 and / or a relative position of the sensing coil relative to the armature changing rotational relative movements between measuring tube 10 and counteroscillator 20th If required, the sensor coil 51a to be fixed to the measuring tube 10 but also the counter-oscillator 20, and correspondingly the coupled with this armature 51 b.

p0083[0075] According to another embodiment of the invention is also provided to establish vibration exciter and vibration sensors according to the same principle of action, esp. In substantially identical form today. Furthermore, it is also possible to coil and / or armature of the excitation and / or sensor arrangement, waiving any switching lever to fasten each directly on the measuring tube or on the counter-oscillator.

p0084[0076] According to another embodiment of the invention, measuring tube 10, counter-oscillator 20, and attached thereto sensor and exciter arrangements 40, 50 further tuned with respect to their mass distribution to one another that the, suspended thus formed by means of the inlet and outlet tube pieces 11, 12 inner part of the transducer a Gravity MS which lies at least within the measuring tube 10, but preferably as close to the measuring tube L. In addition, the inner part is further adapted to a to the inlet tube piece 11 and the outlet tube 12 aligned and at least partially disposed within the measuring tube 10 first principal axis of inertia T₁ having. Due to the positioning of the center of mass MS of the internal part, esp. But also due to the aforementioned position of the first principal axis of inertia T₁ can the torsional oscillations and the bending oscillations of the measuring tube 10 are at least mechanically decoupled from one another largely in the wanted mode.

p0085[0077] The inner part transducer constructed in accordance with another embodiment of the invention such that a first principal axis of inertia T₁ it coincides with the top longitudinal axis L substantially. Further, the inner part of the transducer according to another embodiment of the invention configured such that a second principal axis of inertia T₂ thereof substantially coincides with the aforementioned central axis.

p0086[0078] The means of the measuring tube 10, the counter-oscillator 20, the

p0087Inlet tube piece 11 and outlet tube 12 formed inner part of the measuring transducer is, as can be seen from a combination of FIGS. 1 and 2, further medium-tight in a selbiges inner part and largely pressure-tight enclosing the transducer housing 30 supported swingably that at each remote from the coupling zones end of input and outlet tube pieces 11, 12 is fixed accordingly. In the event that the transducer is detachably be mounted to the pipeline, is the inlet tube piece 11 and outlet tube 12 are respectively a first and second flanges 13, 14 formed accordingly. The flanges 13, 14 can thereby be simultaneously formed as an integral part of the transducer housing 30th If required, the inlet and outlet 11, 12 but also directly with the pipeline, eg by means of welding ode be r brazing, respectively.

p0088[0079] To connect the exciter mechanism as well as the sensor arrangement to the mentioned operating and evaluation electronics of the inline measuring device of the other corresponding connection lines are provided which are guided at least partly within the transducer housing. The connecting lines can thereby be at least partially formed as electrical, at least in sections in enveloped by an electrical insulation wires, eg in the form of "twisted pair" cables, ribbon cables and / or coaxial cables. Alternatively or in addition to the leads can be formed at least in sections by means of conductor tracks of, esp. Flexible, optionally lacquered board. According to another embodiment of the invention, the transducer according to the invention, as well as from the combination of FIGS includes. 2 and 5A to 5D can be seen, to further improve the accuracy of measurement and on the basis of the initially mentioned in US-A 2007/0186685, US 2007/0119265 A, US-A 2007/0119264, US-B 66 91 583, or US-B 68 40 109 proposed transducer further includes a coupled in the first coupling zone to the inlet tube piece 11 and the tube 10 first boom 15, which - as shown in Figure 3a schematically -. a lying in the region of the inlet tube piece 11 of mass M₁₅ having, and a coupled in the second coupling zone with the outlet tube 12 and the tube 10 second boom 16, the - 5a as shown also in Fig schematically -. a lying in the region of the outlet tube 12 of mass M₁₆ having. In other words, the two, esp. In substantially identical, possibly even another identical cantilevers 15, 16 are arranged in the measuring transducer that the respective center of gravity M₁₅, M₁₆ by the measuring tube 10, esp. in the Escape lying spaced. The two cantilevers 15, 16 are so far eccentrically on the inlet and outlet and accordingly also eccentric to the measuring tube 10 and supported counter-oscillator 20th The operation of the inner part thus formed corresponds to the features mentioned in the US-A 2007/0186685, US-A 2007/0119265, US-A 2007/0119264, US-B 66 91 583, or US-B 68 40 109 shown Internal parts.

p0089[0081] To a most simple, cost-effective manufacturing of enabling boom as finally the transducer, each of the two cantilevers 15, 16 may be formed, for example, substantially tubular or sleeve-shaped, so that it practically means a pushed onto the counter-oscillator 20, esp. metallic sleeve may be formed, esp., even if the counter-oscillator 20 has been already connected to the measuring tube 10. According to a development which each of the case the respective cantilevers 15, 16 forming sleeves each having at least one annular groove on. See also the therefor mentioned US-A 2007/0186685, US-A 2007/0119264 or US-A 2007/0119265.

p0090[0082] For the preparation of the measuring tube, inlet and outlet tube, the counter-oscillator and the optionally provided booms may otherwise be virtually any of the commonly employed for such transducer materials such as steel, titanium, tantalum, zirconium, etc., or appropriate combinations of these materials used will. For example, the use of titanium for the measuring tube 10 and the inlet tube piece 11 and outlet tube 12 has been shown to be particularly suitable, whereas, for example, for reasons of cost savings, both for the counter-oscillator 20, and optionally provided cantilevers 15, 16 as well as for the transducer housing 30 the use of steel is quite advantageous.

p0091[0083] As already mentioned, consists in measuring transducers of the above-mentioned type, esp. Those with a straight measuring tube, a particular problem is that the transducers not only natural oscillation modes in both the imaginary primary oscillation plane XZ and in the orthogonal imaginary secondary -Schwingungsebene YZ may comprise, but that in addition also at least some of the vibration modes in the secondary vibration YZ plane can have such a natural resonant frequency that can be substantially equal to a natural resonance frequency of an extent corresponding vibration mode in the primary oscillation plane XZ. Such mutually corresponding vibrational modes can also also each mode shapes of the same order, so equal numbers nodal having.

p0092[0084] Taking this into account, therefore, further comprises a first spring element 61 and a second spring member 62 is provided in the transducer according to the invention. Each of the at least two, for example, substantially identical formed, spring elements is - as well as in Figures 6a to 8b schematically shown -. Fixed with a respective meßrohrseitigen first end on the measuring tube 10 and with a respective opposite schwinger side second end to the counter-oscillator 20, for example, in each case at the same distance to the center of the measuring tube. The spring elements are inventively arranged so the transducer that each of the two spring element 61, 62 respectively, both of each of the two coupling zones 11 #, 12 # and of the exciter arrangement 40 spaced anchored with measuring tube and counter-oscillator and the extent of the two coupling zones 11 # , 12 # and of the exciter arrangement 40 spaced on the measuring tube and counter-oscillator acts. Preferably, the first spring element 61 is the second spring member 62 spaced to the measuring tube and the counter-oscillator is fixed, so that, therefore, both the meßrohrseitigen ends as well as the counter-oscillator-side ends of the two spring elements 61, 62 are each spaced apart.

p0093[0085] In particular, it is additionally provided, the spring elements 61, 62 respectively with the meßrohrseitigen first end to form a respective substantially rigid and / or substantially play-free support on the measuring tube and the opposite schwinger side second end to form a respective substantially rigid and / or substantially play-free support to fix the counter-oscillator.

p0094[0086] With respect to the actual position within the transducer as well as the number of spring elements ultimately used to now different design options and variants of which are explained in detail below some selected result.

p0095[0087] According to another embodiment of the invention, as well as in the FIGS. 6a, 7a and 8a shown schematically, fixed the first spring element in between the first coupling zone 11 # and the at least one vibration exciter lying inlet-side area of ​​the measuring tube and counter-oscillator. This embodiment further, it is also provided to fix the second spring element in between the second coupling zone 12 # and the at least one vibration exciter lying outlet area of ​​the measuring tube and counter-oscillator. According to another embodiment of the invention is further provided, the spring element 61, 62, such as to arrange also from the combination of FIGS. 7a and 7b seen in the measuring transducer that that first spring element 61 along a parallel to the longitudinal axis L extending imaginary side of the measuring tube 10 fixed on that which is diametrically opposite to this a likewise parallel imaginary side of the measuring tube 10, along the second spring element 62 is fixed with its end on the measuring tube meßrohrseitigen substantially. In particular, this is furthermore provided that the two spring elements 61, 62 In addition, point-symmetrical with respect to a center of gravity of the measuring tube 10, or the mentioned center of mass MS of the measuring transducer are arranged in same. In other words, should the meßrohrseitigen ends of the two spring elements 61, 62 are advantageously on a common passing through the center of gravity imaginary diagonal line of the transducer; alike are then also against schwinger ends of the two spring elements 61, 62 on an imaginary common further, also passing through the focus of the transducer size. This arrangement of the spring elements has inter alia the advantage that not only very effective frequencies shifts between resonant frequencies corresponding vibrational modes in the primary and secondary vibration level can be achieved, but also in addition to very easily create an additional frequencies shift between the resonant frequencies of the mentioned torsional oscillations of the measuring tube and where the Lateral oscillations, especially, which can be in the primary vibration level, realized without thereby such as to hinder the excitation of torsional oscillations significantly.

p0096[0089] According to one embodiment of the invention, the at least two

p0097Spring element 61, 62 is constructed and arranged in the measuring transducer, that a lowest natural frequency of the above-mentioned first natural mode of oscillation is set to be smaller in the imaginary primary vibration plane by means of two spring elements, as a lowest natural frequency of the second natural mode of oscillation in the imaginary secondary vibration level , In particular, is hereby also provided, the transducer in such a way that a frequency spacing between the lowest natural frequency of the first natural oscillation mode and the lowest natural frequency of the second natural mode of oscillation is greater than 50 Hz esp. Greater than 100 Hz, is set.

p0098[0090] According to a further embodiment of the invention is therefore further provided that each of the two spring elements 61, 62 has a spring stiffness of the respective bending vibrations of the measuring tube in the primary oscillation plane XZ inhibiting primary component is different from a bending oscillations of the measuring tube in the secondary vibration plane YZ inhibiting secondary component. In particular, it is provided that each of the two spring elements 61, 62 formed and arranged in the measuring transducer, that the primary component of its spring rigidity is each smaller than the associated secondary component.

p0099[0091] The above-mentioned difference between the primary and associated

p0100Secondary component can be achieved for the respective spring element, for example, in a simple manner by the fact that - for example, from the combination of FIGS. 6a and b can be seen, or as exemplified in Figure 9 by means of the first spring member 61, -. A of each of the spring elements is in each case as an elongated body, such as a rod, a coil spring, a leaf spring or the like is formed and each arranged in the measuring transducer, that it in operation as a result of Bending oscillations of the measuring tube 10 in the primary vibration level, to one of two respective spring element ends imaginarily connecting longitudinal axis in the manner of a both ends clamped string is transversely bent.

p0101[0092] According to a further advantageous embodiment, therefore, each of the esp. Identical, spring elements respectively by a, esp. Metallic, formed rod. The use of a metallic bar as a spring element has, apart from a comparably simple, nevertheless very robust construction of the spring elements, with a very good spring action, in particular the advantage that can be drawn upon in manufacturing also readily standardized, insofar also inexpensive commodity can.

p0102[0093] Further, the spring elements are arranged according to a further embodiment of the invention, in the measuring transducer, characterized in that each of the formed as an elongate body, esp. Bar- or rod-like spring elements extending in the radial direction to the measuring tube and / or the counter-oscillator substantially. Alternatively, it can definitely be advantageous, especially in large extent fluctuating operating temperatures and associated with it, by thermally induced expansions caused in the radial direction changes the relative distance between the measuring tube and counter-oscillator when selbiges rod-shaped spring element with respect to the measuring tube 10 or its longitudinal axis L inclined and / or bent slightly and thus is slightly radially resilient.

p0103[0094] According to another embodiment of the invention the two spring elements are placed in the measuring transducer, that each of the two spring elements is arranged in an imaginary plane passing through the intake-side portion and the outlet-side area straight sectional plane of the measuring tube. Alternatively or in addition to it is further provided that each of the two, for example, rod-shaped or rod-shaped, spring elements mounted on a pro rata imaginary intersections of the measuring tube with the intended secondary vibration plane YZ. Furthermore, it is provided that each of the two spring elements is mounted on a pro rata imaginary intersections of the counter-oscillator with the secondary vibration plane YZ. In the event that the spring elements are each formed as a substantially elongated body and the one hand, respectively on the imaginary intersection points of the measuring tube with the imaginary secondary vibration level and on the other hand respectively to the imaginary intersection points of the counter-oscillator with the

p0104Secondary vibration plane YZ are stored, both of which are preferably arranged in the measuring transducer that it effectively within the secondary vibration plane YZ. According to a further embodiment of the invention the spring elements are further arranged in the measuring transducer, that the first spring element is fixed at least in the vicinity of an intake-side peripheral line of the measuring tube on the latter along which the said first vibration sensor - inlet-side here - effectively detected movements of the measuring tube, and that the second spring element is fixed at least in the vicinity of an outlet-side circumferential line of the measuring tube on the latter along the mentioned second vibration sensor - effectively detected movements of the measuring tube - outlet-side here. This configuration further optimizing the spring element are further arranged in the measuring transducer that the first spring element and the mentioned first vibration sensor are then proportionately fixed along at least the extent common inlet-side periphery of the measuring tube on the latter, and that the second spring element and said second vibration sensor then proportionately are fixed along at least the extent common outlet periphery of the measuring tube at this. This is the extent of particular advantage at least suppressed as unwanted flow tube vibration in the secondary vibration level at each vibration sensor so extremely effective, rod-shaped design spring elements can even be almost completely prevented in the case of rod or. As a result, a very simple, nevertheless very effective manner, a coupling, for example, introduced from the outside in the transducer, in the secondary vibration level acting, mechanical disturbances in the power supplied by the vibration sensors vibration signals are pins must almost completely and safely. This allows for example the use of such vibration sensors, which has a certain inherent cross-sensitivity to vibrations in the secondary vibration level, and which can be produced at lower cost due to their extent comparatively simpler structure.

p0105[0096] According to another embodiment there is further provided that

p0106to fix spring members along a non-distorting in biegeschwingendem in the primary vibration level measuring tube substantially neutral axis of the measuring tube on that. For the described case that also the counter-oscillator during operation, at least at times, bending oscillations about the bending axis of vibration, it is further provided that the spring elements along at biegeschwingendem counteroscillator not distorting essentially neutral axis of the counter-oscillator are fixed on that. The attachment of the spring elements along the neutral fibers of the measuring tube and the counteroscillator can, for example, also be achieved in that a torsional vibrations of the measuring tube to the flexural oscillation axis substantially coincident Torsionsschwingungsachse effectively inhibiting spring stiffness of the spring elements is minimized, and thus only a small influence on the behavior of the has transducer at torsionsschwingendem measuring tube.

p0107[0097] Further examples of suitable constructive embodiments of the spring elements and / or their arrangement relative to the primary and secondary vibration level, moreover, in the above-mentioned US-A 52 91 792 or US-B 70 77 014 or in U.S. -A 48 23 614 shown.

p0108[0098] According to a development of the invention also contain an additional third spring element 63 and a fourth spring element 64. comprises the transducer, as well as in FIGS. 8a schematically, The, for example, again essentially identical, spring elements are here again as the transducer arranged that each of the four now Spring elements 61, 62, 63, 64 - as well as from the combination of Figure 2 and Figure 8a visible -..., Respectively, both of the coupling zones 11 #, 12 # and of the exciter arrangement 40 spaced on the measuring tube 10 and counter-oscillator 20 is fixed In particular, the spring elements 61, 62, 63, 64 are further arranged in the measuring transducer, that each of the four spring elements is also in each case spaced apart from each of the respective other three spring elements. In especial, the spring elements are arranged so that - as from the combination of FIGS 8a and 8b readily apparent - on the other pairs that belong together spring elements, in this case the first and third spring element 61, 63 on the one hand and the second and fourth spring member 62, 64th , each substantially diametrically opposite one another. As can be seen easily from the foregoing explanations, the transducer according to the invention is characterized by a variety of settings that enable the skilled person having regard to the present invention, a separation of resonant frequencies selected vibrational modes of the measuring tube in the primary and secondary vibration level to achieve a high quality, esp. even after a specification of external or internal mounting dimensions of the transducer. The real implementation in the individual parameters to be set for the required stiffness of the spring elements as well as their respective optimal positioning in the measuring transducer can thereby be readily adapted to the through the measuring tube 10 actually planned nominal diameter DN as well as the time allotted for the measuring tube insertion length accordingly , The transducer according to the invention is substantially greater than 40 for both measuring tubes with more smaller sizes DN in the range of less than 40 mm and in particular for use in piping with an issue calibration of more than 50 mm and, consequently, also for measuring tubes with diameters of mm suitable.