Title of Invention

VIBRATORY MEASUREMENT PICKUP

Abstract The measurement pickup includes a pickup housing (10), which exhibits a plurality of natural oscillation modes, as well as at least one first pickup tube (4) held oscillatably in the pickup housing (10), vibrating at least at times, and conveying at least a portion of the medium to be measured. Additionally, the measurement pickup includes an electromechanical, especially electrodynamic, exciter arrangement (60) acting on the at least one pickup tube for producing and/or maintaining mechanical oscillations of the at least one pickup tube (4), and a sensor arrangement reacting to movements of the pickup tube (4), especially bending oscillations, for producing at least one oscillation measurement signal (svb) representing oscillations of the pickup tube (4). Additionally, for improving the oscillation properties and, consequently, also the measurement accuracy of the measurement pickup, at least three coupling elements are provided for connecting the first and second pickup tubes (4,5) together at the inlet end, as well as at least three coupling elements (218) for connecting the first and second pickup tubes (4, 5) together at the outlet end. By using at least six coupling elements, it is possible to produce vibration-type measurement pickups of high measuring accuracy even at large nominal diameters of more than 150 mm, especially also while largely maintaining already established and proven forms of construction.
Full Text FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)
1 TITLE OF INVENTION - VIBRATORY MEASUREMENT PICKUP
2 APPLICANT(S;

a) Name
b) Nationality
c) Address

ENDRESS+HAUSER FLOWTEC AG SWISS Company KAEGENSTRASSE 7, CH-4153 REINACH, SWITZERLAND

3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

The invention relates to a vibration-type measurement pickup for measuring a flowable medium, especially a gas, liquid, powder or other flowable substance, conveyed in a pipeline.
In the technology of process measurements and automation, physical parameters, such as e.g. mass flow rate, density and/or viscosity, of a medium flowing in a pipeline are often measured using inline measuring devices, which include a vibratory measurement pickup, through which the medium flows, and a measurement and operating circuit connected thereto, for effecting reaction forces in the medium, such as e.g. Coriolis forces corresponding to the mass flow rate, inertial forces corresponding to the density of the medium and/or frictional forces corresponding to the viscosity of the medium, etc., and for producing, derived from these forces, measurement signals respectively representing mass flow rate, density and viscosity.
Such measurement pickups, especially those in the form of Coriolis mass flow meters or Coriolis mass flow/density meters, are described in detail e.g. in WO-A 04/099735, WO-A 04/038341, WO-A 03/076879, WO-A 03/027616, WO-A 03/021202, WO-A 01/33174, WO-A 00/57141, WO-A 98/07009, US Patent Nos. 6,807,866, 6,711,958, 6,666,098,6,308,580,6,092,429,5,796,011,5,301,557,4,876,898, EP-A 553 939, EP-A1001 254, EP-A 12 48 084, EP-A 1 448 956, or EP-A 1 421 349. For conveying the medium flowing at least at times, the measurement pickups include at least one pickup tube, which is secured appropriately to a usually thicker-walled, especially tubular and/or beam-like, support cylinder or in a support frame. Additionally, the aforementioned measurement pickups have a second pickup tube, which likewise vibrates, at least at times, and is mechanically coupled with the first pickup tube at least via two, especially, however, four, coupling elements, also named node plates or couplers, with at least the first pickup tube being constructed as a first measuring tube communicating with the pipeline and serving for conveying the medium to be measured. For producing the above-mentioned reaction forces, the two pickup tubes are caused to vibrate during operation, driven by a usually electrodynamic exciter arrangement, with the two pickup tubes usually executing bending oscillations, at least at times, about an imaginary oscillation axis essentially parallel to a longitudinal axis of the measurement pickup. For detecting vibrations of the pickup tube, especially inlet and outlet end vibrations, and for producing at least one oscillation measurement signal representing such, such measurement pickups additionally include a sensor arrangement reacting to movements, and thus also to mechanical oscillations, of the pickup tube.
During operation, the above-described, internal oscillation system of the measurement pickup, formed by the at least one pickup tube, the medium conveyed at least instantaneously therein, as well as at least partly by the exciter arrangement and the sensor arrangement, is excited by means of the electromechanical exciter arrangement at least at times in a wanted oscillation mode to execute mechanical oscillations at least one dominating, wanted oscillation frequency. These oscillations in the so-called wanted oscillation mode are usually, at least partly, in the form of lateral oscillations, especially when the measurement pickup is used as a Coriolis mass flow and/or density meter. Usually chosen as the wanted oscillation frequency in such cases is a natural, instantaneous, resonance frequency of the internal oscillation system, which, in
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turn, depends both on the size, shape and material of the pickup tube and also on an instantaneous density of the medium; if necessary, the wanted oscillation frequency can also be significantly influenced by an instantaneous viscosity of the medium. Due to fluctuating density of the medium to be measured and/or due to medium changes occurring during operation, the wanted oscillation frequency during operation of the measurement pickup is naturally changeable at least within a calibrated and, thus, predetermined, wanted frequency band, which, correspondingly, has a predetermined lower, and a predetermined upper, limit frequency. The internal oscillation system of the measurement pickup formed in common by the at least one pickup tube, together with the exciter and sensor arrangements, is, additionally, usually accommodated by a housing having the support frame, or support cylinder, as integral component, with the housing being mechanically coupled to the pipeline via an inlet end and an outlet end and likewise exhibiting a plurality of natural oscillation modes. Suitable pickup housings for vibratory measurement pickups are described, for example, in WO-A 03/076879, WO-A 03/021202, WO-A 01/65213, WO-A 00/57141, US Patent Nos. 6,776,052, 6,711,958, 6,044,715, 5,301,557, or EP-A 1 001 254.
Progress in the field of vibratory measurement pickups has, in the meantime, reached a level where modern measurement pickups of the described kind can be applied in practice for almost all purposes in the technology of flow measurements and can satisfy the highest requirements existing in such field. Thus, such measurement pickups can be applied to measure mass flow rates of only a few g/h (grams per hour) up to some t/h (tonnes per hour), and pressures of up to 100 bar for liquids, or even over 300 bar for gases. The accuracy of measurement achieved in such applications lies, usually, at about 99.9% of the actual value, or even above, i.e. a measurement error of about 0.1%, while a lower limit of the guaranteed measurement range can lie quite well at about 1% of the end value of the measurement range. On the basis of the high bandwidth, measurement pickups of the described kind can be offered, depending on application, also with nominal diameters, as measured at the flange, lying between 1 mm and 250 mm, or even beyond.
Investigations on vibratory measurement pickups having two, mutually parallel, curved pickup tubes, such as are described e.g. in US-B 6,711,958 or US-B 6,308,580, have shown, however, that, despite a largely symmetrical construction with reference to an imaginary central plane of the measurement pickup extending between the two curved central tube segments of the pickup tubes, alternating imbalances can be produced in significant measure in the rhythm of the wanted oscillation frequency and, consequently, associated disturbance oscillations can be coupled out into the connected pipeline. Proving to be especially harmful, in this regard, for the required, high measurement accuracy are those disturbance oscillations which act in the direction of that principal axis of inertia of the measurement pickup - in the following designated the vertical axis - which lies in the aforementioned, imaginary central axis of the measurement pickup and extends essentially perpendicular to the axis of the oscillations. To diminish such disturbance oscillations, especially those directed transversely to the oscillation axis, it is proposed both in EP-A 12 48 084 and in WO-A 04/099735 to apply a cantilever-like balance-element to a curved, central, middle tube segment of each of the two pickup tubes. The effect of such balance elements lies
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essentially in their ability to generate acceleration forces directed counter to the acceleration forces produced by the vibrating pickup tubes and directed, in the above sense, vertically to the oscillation axis, so that these forces partially cancel one another. Further investigations have, moreover, shown that, in the case of measurement pickups of the described type, especially those with V-shaped or trapezoidally bent, pickup tubes and/or with pickup tubes whose tube diameters amount to 80 mm or more, besides such forces coming mainly from the acceleration of moved masses, to an increasing degree, also clamping forces can also lead to significant imbalances in the measurement pickup, such as are dependent on an asymmetric deformation of the pickup housing stemming from an instantaneous deflection of the pickup tubes.
Figs. 1 and 2 are two schematic sketches for explaining the oscillatory motion in the case of a measurement pickup of the described kind having two curved, mutually parallel, pickup tubes, which are mechanically coupled together at the inlet and outlet ends via, in each case, two coupling elements. The pickup tubes are shown here schematically in simplified form and shown cut free at the ends, thus free of the pickup housing which otherwise holds them, so that they can, therefore, oscillate virtually at their ends. As already mentioned, the two pickup tubes oscillate, during operation, relative to one another, and, indeed, in a way such that they deflect laterally (X-direction) practically over their entire lengths. The amplitudes of these deflections may differ from one another. The predominant part of the oscillations and of the associated forces is thus both perpendicular to the oscillation axis (Z-direction) and to the mentioned vertical axis (Y-direction) of the measurement pickup, wherein, at least for the case that both pickup tubes are flowed through at the same time by the medium, the component of the one pickup tube essentially cancels the corresponding component of the other pickup tube. A smaller component of the forces caused by the oscillations acts also in the direction of the vertical axis (Y-direction). The oscillatory motion of the pickup tubes is, in spite of the coupling elements, transmitted through to the - here free - ends, with also the coupling elements being slightly deformed (Fig. 2). The middles of the coupling elements move in such case also in the direction of the vertical axis, while the "free" ends of the pickup tubes move oppositely in the direction of the vertical axis. This movement of the ends of the pickup tubes leads in the installed and fixed state inversely to forces in the securing pickup housing, for example in the possible, connected distributor pieces, and, thus, also to deformations of the pickup housing.
A possibility for reducing such undesired forces in the mounting, which, for example, can vary a calibrated zero point of the measurement pickup, would, for example, be correspondingly to increase a stiffness of the pickup housing resisting the aforementioned deformations of the pickup housing by increasing its wall thickness. However, a special problem connected with such a measure is that, in the case of measurement pickups of large nominal diameter, the installed mass is already very high. For measurement pickups of nominal diameter far in excess of 150 mm, including flanges possibly attached thereto, the installed mass can lie easily at about 500 kg. Thus, in the case of measurement pickups of large nominal diameter, the possibilities for sufficient stiffening of the pickup housing by increased material thicknesses must be considered as very limited, at least for the desired application of proven materials, especially stainless steel.
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Proceeding from the above-related state of the art, it is thus an object of the invention to provide vibratory measurement pickups which, especially while largely retaining already established and proven forms of construction, also with large nominal diameters in excess of 150 mm, exhibit as high a measurement accuracy as possible, thus of 99.8% or more, and thus a measurement error of less than 0.02%.
For achieving the object, the invention provides a measurement pickup of vibration-type for measuring a flowable medium, especially a gas, liquid, powder or other flowable substance, conveyed in a pipeline, including:
- a pickup housing, which is mechanically coupled with the pipeline via an inlet end and an outlet end;
- at least one first pickup tube held in an oscillatable manner in the pickup housingand vibrating at least at times, and a second pickup tube mechanically coupled with the first pickup tube and likewise vibrating at least at times;
- with the first pickup tube and the second pickup tube executing during operation, at least at times, bending oscillations each about an imaginary oscillation axis extending essentially parallel to a longitudinal axis of the measurement pickup, and
- with at least the first pickup tube being embodied as a first measuring tube communicating with the pipeline and serving to convey the medium to be measured;
- an electromechanical, especially electrodynamic, exciter arrangement acting on at least one of the pickup tubes for producing and/or maintaining mechanical oscillations of the at least one pickup tube;
- a sensor arrangement reacting to movements at least of the first pickup tube, especially to bending oscillations, for producing at least one oscillation measurement signal representing oscillations of the first pickup tube; as well as
- at least three coupling elements, especially plate-shaped coupling elements, connecting the first and second pickup tubes together at their inlet ends, as well as at least three coupling elements, especially plate-shaped coupling elements, connecting the first and second pickup tubes together at their outlet ends.
Additionally, the invention includes that the measurement pickup for measuring a flowable medium conveyed in a pipeline has a caliber of greater than 150 mm, especially of 250 mm or more, and/or is for measuring a mass flow rate of a medium flowing through a pipeline in amounts at least at times greater than 900 t/h, especially, at least at times, more than 1200 t/h.
According to a first embodiment of the measurement pickup of the invention, the two pickup tubes oscillate during operation with phases essentially opposite to one another.
In a second embodiment of the measurement pickup of the invention, each of the two pickup tubes has an at least sectionally curved, especially essentially U-, V- or trapezoid-shaped, central, middle tube segment.
A third embodiment of the measurement pickup of the invention provides that the inlet-end coupling elements and the outlet-end coupling elements are so arranged and fixed on the two pickup tubes that those clamping forces produced by the vibrating pickup tubes within the pickup housing are minirnized, which act predominantly in the
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direction of that principal axis of inertia of the measurement pickup, that runs essentially perpendicular to the longitudinal axis and lies essentially in an imaginary central plane of the measurement pickup extending between the two curved middle tube segments of the pickup tubes.
According to a fourth embodiment of the measurement pickup of the invention, each of the two pickup tubes has at an inlet end a straight inlet tube segment extending essentially parallel to the imaginary oscillation axis. The inlet tube segment communicates with its middle tube segment via an inlet-end, curved, intermediate tube segment. In turn, each of the two pickup tubes has at an outlet end a straight outlet tube segment extending essentially parallel to the imaginary oscillation axis. The outlet tube segment communicates with its middle tube segment via an outlet-end, curved, intermediate tube segment.
In a fifth embodiment of the measurement pickup of the invention, there are at least one first and at least one second coupling element of the coupling elements connecting the two pickup tubes on the inlet end with one another, which coupling elements are each affixed to the inlet-end, intermediate tube segments of the first and second pickup tubes, and there are at least one first and at least one second coupling element of the coupling elements connecting the two pickup tubes on the outlet end with one another, which coupling elements are each affixed to the outlet-end, intermediate tube segments of the first and second pickup tubes.
A sixth embodiment of the measurement pickup of the invention provides that at least one, third coupling element of the coupling elements connecting the two pickup tubes together on the inlet end is fixed to the inlet-end tube segment of the first and second pickup tubes and that at least one, third coupling element of the coupling elements connecting the two pickup tubes together on the outlet end is fixed to the outlet-end tube segment of the first and second pickup tubes.
According to a seventh embodiment of the measurement pickup of the invention, the first pickup tube runs essentially parallel to the second pickup tube.
In an eighth embodiment of the measurement pickup of the invention, the first measurement pickup tube is essentially constructed identically to the second measurement pickup tube.
A ninth embodiment of the measurement pickup of the invention includes, additionally, a first distributor piece connecting the first and second pickup tubes together at the inlet end, as well as a second distributor piece connecting the first and second pickup tubes together at the outlet end, with the second pickup tube likewise being constructed as a second measuring tube serving for the conveying of the medium to be measured and for communicating with the pipeline. According to a further development of this embodiment of the invention, each of the two distributor pieces has a mass of more than 10 kg, especially more than 20 kg.
According to a tenth embodiment of the measurement pickup of the invention, the
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pickup housing includes a support element, especially one of steel, to which the at least one pickup tube is mechanically connected at its inlet and outlet ends. In a further development of this embodiment of the invention, the support element is constructed in the form of support cylinder, especially a tubular support cylinder, which is at least partially laterally open. The support cylinder is connected with the at least one pickup tube such that its at least one, curved tube segment protrudes laterally out of the support cylinder. According to another embodiment of this further development of the invention, the support element has a mass of at least 70 kg, especially more than 140 kg, and/or a length of at least 1000 mm, especially of more than 1200 mm.
In an eleventh embodiment of the measurement pickup of the invention, each of the pickup tubes, as well as the pickup housing, is made, at least in part, of steel, especially stainless steel.
A twelfth embodiment of the measurement pickup of the invention provides that each of the pickup tubes has a mass of at least 10 kg, especially of greater than 25 kg.
According to a thirteenth embodiment of the measurement pickup of the invention, each of the pickup tubes has an inner diameter of at least 80 mm, especially greater than 100 mm.
In a fourteenth embodiment of the measurement pickup of the invention, each of the pickup tubes has a cross section whose area moment of inertia is greater than 2 x 104 mm3, especially greater than 4 x 106 mm4.
In a fifteenth embodiment of the measurement pickup of the invention, each of the pickup tubes has a cross section whose section modulus resisting bending is greater than 106 mm4, especially greater than 2 x 106 mm4.
According to a sixteenth embodiment of the measurement pickup of the invention, each of the pickup tubes has a stretched length of at least 1000 mm, especially greater than 1500 mm.
A seventeenth embodiment of the measurement pickup of the invention provides that each of the middle tube segments of the two pickup tubes has an essentially V-shape and each of the middle tube segments of the two pickup tubes has a peak with an included angle smaller than 150°, especially smaller than 120°.
According to an eighteenth embodiment of the measurement pickup of the invention, an internal oscillation system of the measurement pickup is formed by the two pickup tubes, the medium at least instantaneously conveyed therein, and at least in part by the exciter arrangement and the sensor arrangement, and the internal oscillation system, driven by the exciter arrangement, executes during operation of the measurement pickup, at least at times, mechanical oscillations, especially in the form of lateral oscillations, with at least one wanted oscillation frequency, which depends both on the size, shape and material of the pickup tube and on an instantaneous density of the medium, and which is changeable during operation of the measurement pickup, within
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a predetermined wanted frequency band having upper and lower limit frequencies. In a further development of this embodiment of the invention, a total mass of the internal oscillation system amounts to at least 70 kg, and especially during operation, at least at times, to more than 90 kg.
In a nineteenth embodiment of the measurement pickup of the invention, an external oscillation system of the measurement pickup is formed by the pickup housing and at least by the distributor pieces, while an internal oscillation system of the measurement pickup is formed by the two pickup tubes, the medium at least instantaneously conveyed therein and at least in part by the exciter arrangement and the sensor arrangement, and the internal oscillation system, driven by the exciter arrangement, executes during operation of the measurement pickup, at least at times, mechanical oscillations, especially in the form of lateral oscillations, having at least one wanted oscillation frequency, which depends both on the size, shape and material of the pickup tube and on an instantaneous density of the medium, and which is changeable during operation of the measurement pickup within a predetermined wanted frequency band having lower and upper limit frequencies. According to a further development of this embodiment of the invention, a total mass of the external oscillation system amounts to at least 200 kg, especially to more than 300 kg. In another further development of this embodiment of the invention, a mass ratio of a total mass of the external oscillation system to a total mass of the internal oscillation system is, during operation, at least at times, especially, however, continuously, smaller than 3, especially smaller than 2.5.
According to a twentieth embodiment of the measurement pickup of the invention, an installed mass to nominal diameter ratio of an installed mass of the total measurement pickup to a nominal diameter of the measurement pickup, which corresponds to a caliber of the pipeline in whose course the measurement pickup is to be installed, amounts to at least 1.5, especially more than 2. In a twenty-first embodiment of the measurement pickup of the invention, the installed mass of the total measurement pickup is greater than 200 kg, especially greater than 400 kg.
A basic idea of the invention is to suppress the disturbance oscillations produced by means of the at least six coupling elements possibly in the end regions of the vibrating pickup tubes, especially in the region of the intermediate segments, especially disturbance oscillations acting in the direction of the vertical axis of the measurement pickup. The invention is based here on the surprising discovery that through the use of at least 2x3 coupling elements and their arrangement each in the region of the intermediate segments, as compared to conventional measurement pickups with 2x2 coupling elements, an effective direction especially of oscillation-based deformations in the pickup housing, or of clamping forces arising in the distributor pieces, can be rotated into a direction less damaging for the measurements and, at the same time, at least the disturbance oscillations otherwise acting in the direction of the vertical axis can also be considerably minimized. Thus, the at least three coupling elements mounted on the pickup tubes at the inlet end and the at least three coupling elements mounted on the pickup tubes at the outlet end act, from a practical point of view, as mechanical polarization filters, which are so constructed that at least disturbance oscillations acting in the direction of the vertical axis of the measurement pickup are suppressed or even
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eliminated.
An advantage of the invention is, among other things, that, compared to conventional measurement pickups with four coupling elements, already the use of two additional coupling elements and, thus, in comparison to conventional measurement pickups, without great additional effort, a large, and, in the best case, even an almost complete, canceling of the most disturbing clamping forces, especially those acting in the direction of the vertical axis of the measurement pickup, can be realized. Thus, a further advantage of the invention can be seen in the fact that such leads to a possibility for realizing vibration-type measurement pickups even at large nominal diameters of over 150 mm, especially at nominal diameters of greater than 200 mm, which are both economically reasonable and also have an installed mass which is manageable. A further advantage of the invention is that, at the same time, already established and proven construction forms, especially with respect to the pickup tubes, can also largely be retained.
The measurement pickup of the invention is, consequently, also suitable for the measurement of flowable media, which are conveyed in a pipeline having a caliber of greater than 150 mm, especially of 250 mm or above. Moreover, the measurement pickup is also suited for the measurement of mass flow rates, which are, at least at times, greater than 900 t/h, especially, at least at times, more than 1200 t/h, such as can arise e.g. in the case of applications for measuring oil, natural gas or other petrochemical substances.
The invention will now be explained in greater detail on the basis of examples of embodiments and the figures of the drawing. Functionally equal parts are provided in the separate figures with the same reference characters, which, however, are repeated in subsequent figures only when such appears helpful.
Figs. 1, 2 are schematic sketches of different side views for explaining thoscillatory motion of conventional measurement pickups,
Figs. 3a, b show different side views of an inline measuring device serving, for example, as a Coriolis mass flow/density and/or as a viscosity measuring device, and
Figs. 4 to 6 show, in different, partially sectioned side views, details of a vibration-type measurement pickup suited for an inline measuring device as shown in Figs. 3a, b.
Figs. 3a, b show an inline measuring device 1, especially one constructed as a Coriolis mass flow and/or density measuring device, serving, for example, for registering a mass flow rate m of a medium flowing in a pipeline (not shown) and for mapping such into a mass flow rate, measured value Xm instantaneously representing this mass flow rate. The medium can be practically any flowable substance, for example a powder, a liquid, a gas, a vapor, or the like. Alternatively, or in supplementation, the inline measuring device 1 can also be used, if desired, to measure a density p and/or a
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viscosity h of the medium. In particular, the measurement pickup is provided for measuring media such as oil, natural gas or other petrochemical substances, which flow in a pipeline having a caliber of greater than 150 mm, especially a caliber of 250 mm or greater, and/or which exhibit, at least at times, a mass flow rate of greater than 900 t/h, especially greater than 1200 t/h.
For measuring the medium, the inline measuring device includes a vibration-type measurement pickup 10, through which the medium flows during operation, as well as a measuring device electronics 20 (shown here only schematically in the form of a labeled block) electrically connected with the measurement pickup 10. Advantageously, the measuring device electronics 20 is designed such that it can, during operation, exchange measurement and/or other operational data with a measured value processing unit, for example a programmable logic controller (PLC), a personal computer and/or a work station superordinated thereto, via a data transmission system, for example a field bus system. Additionally, the measuring device electronics is designed such that it can be fed from an external power supply, for example even over the aforementioned field bus system. For the case that the inline measuring device is to be coupled to a field bus or other communication system, the measuring device electronics 20, especially a programmable version thereof, additionally has a corresponding communications interface for a data communications, e.g. for transmitting measured data to the above-mentioned programmable logic controller or a superordinated process control system.
Figs. 3a, b, and 4 to 6 show in various types of drawings an example of an embodiment of a measurement pickup 1 serving especially as a Coriolis mass flow, density and/or viscosity pickup. As already mentioned, the measurement pickup 1 serves to produce in a through-flowing medium mechanical reaction forces, especially Coriolis forces dependent on mass flow rate, inertial forces dependent on density of the medium and/or frictional forces dependent on the viscosity of the medium, forces which react measurably, that is registerably by sensor, on the measurement pickup. Derived from these reaction forces describing the medium, for example the mass flow rate, the density and/or the viscosity of the medium can be measured by means of evaluation processes correspondingly implemented in the measuring device electronics in manner known to those skilled in the art. The measurement pickup 1 is, in operation, inserted via flanges 2, 3 into the course of a pipeline (not shown) flowed through by a medium to be measured, especially a powdered, liquid, gaseous or vaporous medium. Instead of flanges, the measurement pickup 1 can also be connected to said pipeline by other known means, such as e.g. triclamp, or screwed, connections.
For conveying at least a portion of the medium to be measured, the measurement pickup includes at least one pickup tube 4 serving as measuring tube and held oscillatably in a pickup housing 10. In use, tube 4 communicates with the pipeline and, driven by an electromechanical exciter arrangement 60, is caused to vibrate, at least at times, in at least one oscillation mode suited for determining the physical, measured, variable. Besides the especially one-piece pickup tube 4, there is provided, additionally, as shown in Figs. 5 and 6, a second pickup tube 5 in the measurement pickup. Tube 5, which is essentially identical to tube 4, likewise communicates with the pipeline and
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thus serves as second measuring tube of the measurement pickup. During operation, tube 5 likewise executes mechanical oscillations. The oscillations at least of the first pickup tube are registered by a sensor arrangement reacting to its movements, especially its bending oscillations, and are converted into an oscillation measurement signal Svb representing the oscillations. Thus, practically the entire internal oscillation system of the measurement pickup 1, formed by the two pickup tubes 4,5, the medium at least instantaneously conveyed therein, and at least partially by the exciter and sensor arrangements 60, 70, executes during operation of the measurement pickup 1, at least at times, mechanical oscillations with at least one wanted oscillation frequency Fn, with the mechanical oscillations being at least at times, and/or at least partially, lateral oscillations, especially bending oscillations. The wanted oscillation frequency Fn is, at the same time, in manner known to those skilled in the art, dependent both on size, shape and material of the two pickup tubes 4, 5 and also, especially, on an instantaneous density of the medium, and, thus, during operation of the measurement pickup, variable within a predetermined, wanted frequency band AFn exhibiting upper and lower limit frequencies. During operation of the measurement pickup, the instantaneous wanted oscillation frequency Fn of the internal oscillation system is advantageously controlled and adjusted, such that it corresponds essentially to an instantaneous, natural eigenfrequency of the internal oscillation system.
The two, especially at least sectionally, mutually parallel pickup tubes can, as indicated in Figs. 5 and 6 and shown, for example, also in US-B 6,711,958, US-A 5,796,011, US-A 5,301,557, be connected together by means of distributer pieces 11,12 into flow paths flowed through in parallel during operation; they can, however, also, as shown e.g. in US-A 6,044,715, be connected serially together on the basis of sequentially arranged flow paths. It is, however, also possible, as, for instance, proposed in US-B 6,666,098 or US-A 5,549,009, to use only one of the two pickup tubes as measuring tube for the conveying of medium and the other as a blind tube not conveying medium to be measured and serving, instead, for the reduction of intrinsic imbalances in the measurement pickup. According to an advantageous embodiment of the invention, each of the two pickup tubes 4, 5 has at least one middle, tube segment 41, 51 bent at least sectionally in at least one plane. The pickup tubes 4, 5 can, in this connection, as shown in US-B 6,776,052, have a clearly U-shaped form, for example, or, as proposed in US-B 6,802,224 or US-B 6,711,958 and shown in Figs. 4 - 6, be given an essentially V-shape. Furthermore, the pickup tubes can be bent only slightly, as described e.g. in US-A 5,796,011, or, rather, rectangularly or trapezoidally, as shown e.g. in WO-A 01/65213, US-B 6,308,580, US-A 6,092,429, US-A 6,044,715. Suited as material for the pickup tubes are, especially, steel, especially stainless steel, titanium, zirconium or tantalum. Beyond this, however, the material for the pickup tubes can be practically any material usually used, or at least suited, therefor.
In the illustrated example of an embodiment, at least the middle tube segments 41,51 of the two pickup tubes 4,5 are excited at least partially during operation by the action of the electromechanical exciter arrangement 60 at least partly affixed thereto to execute cantilever-type vibrations, in which they are laterally deflected out of the above-mentioned plane and oscillate with essentially opposite phase relative to one another. In doing this, the first and second pickup tubes execute, at least at times during
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operation, bending oscillations about an imaginary oscillation axis essentially parallel to a longitudinal axis L of the measurement pickup. Said differently, at least the middle tube segments 41,51 are caused to oscillate in a bending oscillation mode, in the manner of cantilevers clamped at one end, or the tines of a tuning fork. In a further development of the invention, each of the two central, middle tube segments is curved in essentially V-shape or even trapezoidally. In a further development of this embodiment of the invention, each of the two pickup tubes 4, 5 includes, additionally, on the inlet end a straight inlet tube segment running essentially parallel to the imaginary oscillation axis. Each of these inlet tube segments is in communication with the middle tube segment of its tube, via a curved, inlet-end, intermediate tube segment.
Also, each of the two pickup tubes 4, 5 includes, additionally, on the outlet end a straight inlet tube segment running essentially parallel to the imaginary oscillation axis.
Each of these outlet tube segments is in communication with the middle tube segment of its tube, via a curved, outlet-end, intermediate tube segment. In another development of this embodiment of the invention, each of the middle tube segments exhibits a peak having an included angle smaller than 150°, especially smaller than 120°.
As already mentioned, the measurement pickup 1 is provided especially also for measurements of high mass flow rates in a pipeline of large caliber. Due to this, a further embodiment of the measurement pickup 1 provides that at least the pickup tube 4 serving as measuring tube has an inner diameter measuring at least 80 mm. Especially, at least the pickup tube 4 is constructed such that its inner diameter is greater than 100 mm, especially even greater than 110 mm. In a further embodiment of the invention, the pickup tube 4 has, moreover, a cross section whose area moment of inertia is greater than 2 x 104 mm3, especially greater than 4 x 106 mm4 and/or whose section modulus resisting bending is greater than 106 mm4, especially greater than 2 x 106 mm4. Additionally, in another embodiment of the invention, the pickup tube 4 serving as measuring tube is designed such that it has a stretched length of at least 1000 mm, especially greater than 1500 mm. Consequently, at least for the case that the pickup tube 4 is of steel, this example results in a mass of at least 10 kg, at least for a wall thickness of somewhat over 1 mm. In a further embodiment of the invention, at least the pickup tube 4 is, however, dimensioned such that, due to a relatively great wall thickness of about 5 mm and/or a relatively large stretched length of about 2000 mm, it has a mass of more than 25 kg. It is also to be noted here, that the second pickup tube 5, at least for the case that it likewise serves as measuring tube, is arranged essentially parallel to the pickup tube 4 and is constructed essentially identically to the first pickup tube 4, and, thus, exhibits both the same physical properties and the same geometric properties. Considering that, as a consequence of the special dimensioning, each of the pickup tubes 4,5 weighs well over 10 kg, and, can, therefore, as is clearly evident from the above measurements-data, exhibit a capacity of 10 1 or more, then the internal oscillation system, which includes the two pickup tubes 4, 5, can, at least when a medium of high density is flowing therethrough, reach a total mass of well over 50 kg. Especially in the case of use of pickup tubes of relatively large inner diameter, wall thickness and stretched length, the mass of the internal oscillation system can, consequently, easily be greater than 70 kg, or, at least when medium is flowing therethrough, more than 90 kg.
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Besides the pickup housing 10 and the pickup tubes 4,5 held therein, the measurement pickup 1 includes an electromechanical, especially electrodynamic, exciter arrangement 60 acting on the at least one pickup tube 4 for producing and/or maintaining mechanical oscillations. Furthermore, the measurement pickup includes a sensor arrangement 70 reacting to mechanical oscillations, for example bending oscillations, of the pickup tube 4 for producing at least one oscillation measurement signal sVb representing oscillations of the pickup tube 4. At least the two pickup tubes 4,5, as well as components additionally fixed thereon, such as e.g. part of the exciter arrangement 69 and part of the sensor arrangement 70, thus comprise, for practical purposes, an internal oscillation system of the measurement pickup.
For producing and/or maintaining mechanical oscillations of at least one pickup tube, the exciter arrangement 60 of the illustrated example of an embodiment has at least one oscillation exciter arranged on the two pickup tubes 4,5, in each case in the region of the peak, especially about, in each case, at the middle, or halfway point, of the tube length. The oscillation exciter can be, for example, one of the electrodynamic types, thus an oscillation exciter realized by means of a magnet coil 62 fixed to the pickup tube 5 and an armature 61 correspondingly fixed to the other pickup tube 4 and plunging into the coil 62.
For registering vibrations, at least of the one pickup tube 4, and for producing the at least one oscillation measurement signal svb representing oscillations of the pickup tube 4, there is, as already mentioned, a sensor arrangement provided, by means of which vibrations, especially vibrations at the inlet and outlet ends, of the tube segment 41 can be signalized and fed for further electronic processing, in the manner usual for such measurement pickups. In the illustrated example of an embodiment, the sensor arrangement includes, for this purpose, a first oscillation sensor arranged on the pickup tubes at the inlet ends, and a second oscillation sensor arranged on the pickup tubes 4,5 at the outlet ends. Especially, the second oscillation sensor is essentially identical to, or built the same as, the first oscillation sensor. The oscillation sensors can likewise be of the electrodynamic type, thus each comprised of magnet coils 72,82 fixed to the sensor tube 5 and armatures 71, 81 fixed correspondingly on the other pickup tube 4 for plunging in the magnet coils 72,82. Beyond this, also other oscillation sensors known to those skilled in the art, for example optoelectronic oscillation sensors, can be used. For determining the at least one physical, measured variable on the basis of the at least one oscillation measurement signal svb, the exciter arrangement 60 and the sensor arrangement 70 are additionally, as is usual in the case of such measurement pickups, coupled in suitable manner, for instance galvanically and/or optoelectronically, to a measuring and operating circuit correspondingly provided in the measuring device electronics 20. The measurement and operating circuit, in turn, produces, on the one hand, an exciter signal sxc correspondingly driving the exciter arrangement 60 and controlled, for example, with respect to an exciter current and/or an exciter voltage. On the other hand, the measuring and operating circuit receives the at least one oscillation measurement signal sVb of the sensor arrangement 70 and generates therefrom desired measured values, which can represent, for example, a mass flow rate, a density and/or a viscosity of the medium being measured and which, if necessary, can be displayed on location or, if necessary, further processed at a higher level. The measuring device
13

electronics 20, including the measuring and operating circuit, can, for example, be accommodated in a separate electronics housing 9, which is arranged remotely from the measurement pickup or it can be attached directly to the measurement pickup 1, for example externally on the pickup housing 10, in which case a single, compact device is formed. In the case of the example of an embodiment illustrated here, a neck-like transition piece 8 is, therefore, additionally mounted on the pickup housing to serve for attachment of the electronics housing 9. In Figs. 4 to 6, the transition piece 8 and the electronics housing 9 are, however, omitted; only Fig. 6 shows a mounting surface 63, recessed in a wall of the pickup housing 10, for the transition piece 8. An electrical conduit 64 is arranged in the mounting surface 63, by means of which electrical connections for the exciter arrangement 60 and the sensor arrangement 70, as well as possible other electrical components, such as e.g. pressure and/or temperature sensors provided, if needed, in the measurement pickup 1, can be made.
The pickup tubes 4, 5 of the measurement pickup, as well as the exciter and sensor arrangements applied in each case thereto, are practically completely encased by the pickup housing 10, as is clear from the presentation provided by Figs. 3a, b and 5 and as is, in fact, usual for measurement pickups of such type. The pickup housing serves, thus, not only as holder of the pickup tubes 4,5, but also, additionally, for protecting the internal components of the measurement pickup 1, such as, for example, the exciter and sensor arrangements, and, additionally, other components placed therein, from external, environmental influences, such as e.g. dust or water spray. Beyond this, the pickup housing 10 can also additionally be embodied and dimensioned such that, in the case of possible damage to the pickup tube 4, e.g. by crack formation or bursting, escaping medium is retained as completely as possible within the pickup housing, up to a required maximum gage pressure. Possible choices of material for the pickup housing, especially also the housing cap 7, can include steels, such as structural steel or stainless steel, or also other suitable high-strength materials. In a further embodiment of the measurement pickup, the pickup tube 4, especially an at least sectionally curved one, and the pickup housing are made each of the same material, especially steel or stainless steel, or at least materials which are similar to one another, especially various types of steel. Additionally, it is provided that the flanges are constructed as integral components of the pickup housing, as, in fact, shown in Figs. 3a, b and as is quite common with such measurement pickups, in order to achieve as short an installation length as possible, coupled with as high stability of the measurement pickup as possible; equally, the possibly present distribution pieces 11,12 can also be integrated directly into the pickup housing.
In the case of the example of an embodiment shown here, the pickup housing 10 includes a support element 6 (here illustrated in the form of a laterally at least partially open, support cylinder), which, as shown in Figs. 4 to 6, is mechanically connected at the inlet and outlet ends with the at least one pickup tube, such that the at least one, curved tube segment 41 extends laterally outwards. Additionally, the pickup housing includes a housing cap 7 arranged spaced from the curved middle tube segments of the pickup tubes 4, 5 and fixed to the support element 6, especially permanently and/or sealed against escape of medium. In the case of the example of an embodiment illustrated here, at least the pickup tube 4 is held in the, in this instance, tubular support
14

element 6 at the inlet and outlet ends, such that the oscillatable middle tube segment 41, extending through two cutouts 61,62 of the support element, protrudes laterally out of such and, consequently, into the housing cap 7 likewise fixed on the support element 6. It is to be noted, in this context, that, instead of the essentially tubular support element 6 illustrated here, also a, if need be, solid support cylinder of some other suitable cross section can be used, for example a support element more in the form of a beam.
Depending on which form and stretched length is actually chosen for the pickup tubes 4,5, the here essentially cylindrical support element has a length essentially equal to, or somewhat shorter than, the stretched length of the pickup tubes 4, 5. In keeping with this and the above-mentioned dimensions of the essentially identical pickup tubes 4,5, the support element of this embodiment of the measurement pickup has likewise a length of at least about 1000 mm. Preferably, the cylindrical support element is, however, realized with a length of over 1200 mm. Furthermore, the support element has a mass of at least 70 kg, especially in the case that it is made of steel. According to a further embodiment of the measurement pickup, the support element is, however, constructed and dimensioned such that its mass amounts to more than 140 kg. Accordingly, the measurement pickup of the invention is embodied and dimensioned such that a mass ratio of a total mass of an outer oscillation system composed of the pickup housing and the possibly present distributor pieces to a total mass of the inner oscillation system can be, without more, smaller than 3, especially equal to or less than 2.
The housing cap 7 serving for the housing of the tube segments 41 includes, as indicated schematically in Figs. 3a, b, a channel-shaped cap segment 10c, together with an essentially planar, first lateral housing segment 10a and a second lateral housing segment 10b essentially mirror-symmetrical to the first segment 10a. The form of the cap segment 10c corresponds, as clearly evident from the combination of Figs. 3a and 3b, essentially to that of a toroidal shell. Accordingly, the cap segment 10c has an essentially circular-arc-shaped, preferably semicircularly shaped, cross section of predeterminable radius r and, at least virtually, an essentially circular-arc-shaped, first segment edge 10c' having a radius R significantly larger than the radius r, as well as a second segment edge 10c" formed essentially identically to the first segment edge. In case necessary, both the cross section and the segment edge can be formed less than ideally circular, thus slightly elliptically. As clearly evident from the combination of Figs. 3a, b and 4, the lateral housing segments 10a, 10b are each connected with, respectively, the first and second segment edges 10c', 10c" of the cap segment 10c, via a circular-arc-shaped, first segment edge 10a', respectively 10b', and, indeed, such that the lateral housing segments 10a, 10b are each arranged essentially aligned in a tangential plane of the cap segment 10c and, consequently, toward a tangent which can be constructed on the respective associated segment edges l0ca and l0cb. Stated differently, in each case between the cap segment 10c and the housing segment 10a, and between the cap segment 10c and the housing segment 10b, there is a largely continuous, thus as smooth as possible, transition, so that, in the case of allowable internal gage pressure, almost no, or only very small, bending stresses are produced. Moreover, the housing cap 7 is fixed via a third segment edge 10c+ and a fourth segment edge 10c# of the cap segment 10c, as well as via, in each case, a second segment edge
15

10a", 10b" of the first and second lateral housing segments 10a, 10b, to the support element 6, and, indeed, such that the cap segment, and, thus, the housing segments 10c, 10a, 10b, remain, during operation, spaced from the at least one, vibrating tube segment 4. For manufacture of the housing cap 7, the segments 10c, 10a, 10b are each prefabricated separately and subsequently joined together, especially welded together. Advantageously, in producing the housing cap 7, for example the method for manufacturing a metal cap usable as housing cap 7 described in the already mentioned WO-A 03/021202 can be used, in which such is formed by the welding of two cap halves of essentially identical form, especially such cut out of a plate-shaped stock, with an edge bead, especially a bead in the form of a quarter torus. Additionally, the housing cap 7 can also be e.g. deep drawn from a metal sheet of appropriate thickness.
In one embodiment of the measurement pickup, the housing cap 7 is dimensioned such that it has a mass of at least 10 kg, especially, however, of more than 20 kg, especially in the case of steel as the material of the housing. Considering that the support element can easily have a mass of 70 kg or more, a pickup housing having a mass of at least 80 kg results, especially, however, of more than 160 kg. However, for the above-mentioned case that flanges and/or distributor pieces are provided in the measurement pickup and these are, thus, also part of the external oscillation system, a correspondingly higher mass is to be estimated for the total mass of the external oscillation system and to be appropriately considered in the tuning of the external oscillation system to the internal oscillation system. At least to this extent, the mass of the total external oscillation system can easily amount to 200 kg or considerably more. Especially in the case of applying pickup tubes having an inner diameter of over 100 mm, the mass of the external oscillation system can be far above 300 kg. In the example of an embodiment of the measurement pickup 1 illustrated here, transport hook-in means are provided at the inlet and outlet ends on the support element, as shown schematically in Figs. 4 and 6, these serving as defined attachment points for possible installation-helping means, such as e.g. appropriate cables or bands of lifting tools, in order better to prevent any damaging of the possibly over 500 kg heavy measurement pickup, for example due to inappropriate transport and/or unsuitable choice of hook-in points. For minimizing disturbance oscillations developed on the part of the external oscillation system, especially on the part of the pickup housing, additional, appropriate support elements can be fixed to the pickup housing, such as are described e.g. in the not-pre-published, German patent application DE 102004053883.2.
For tuning mechanical resonance frequencies of the internal oscillation system, as well as for minimizing mechanical stresses and/or vibrations caused by the vibrating tubes at the inlet or outlet ends in the pickup housing, the two pickup tubes 4,5 are connected mechanically together on the inlet end by means of at least three coupling elements 217a, 217b, 217c, as well as on the outlet end by means of at least three coupling elements 218a, 218b, 218c.
In an embodiment of the invention, the coupling elements 217a, 217b, 217c, especially plate-shaped such elements, on the inlet end, as well as the coupling elements 218a, 218b, 218c, especially plate-shaped such elements, on the outlet end are arranged and fixed on the two pickup tubes such that at least those clamping forces produced within
16

the pickup housing by the vibrating pickup tubes 4, 5 are minimized, that act predominantly in the direction of that principle axis of inertia H of the measurement pickup, which runs essentially perpendicularly to the oscillation axis and essentially lies in an imaginary middle plane E of the measurement pickup lying between the two, curved middle tube segments 41,51 of the pickup tubes 4,5, thus in the direction of the vertical axis of the measurement pickup, as already mentioned above. The six coupling elements 217a, 217b, 217c, 218a, 218b, 218c are, in such case, so arranged and oriented that a symmetry of the measurement pickup, existing with reference to the vertical axis H as well as with reference to the mentioned middle plane, is maintained, this effort towards symmetry being evident without more from Fig. 4 and being usual for measurement pickups of the described kind.
It has been found, surprisingly, in such case, that, be it by their dimensioning and/or their positioning on the two pickup tubes 4,5, the wanted oscillation frequency Fn of the internal oscillation system can be still be influenced predominantly by means of the coupling elements 217a, 218a nearest to the halfway point of the pickup tubes, while the coupling elements 217c, 218c farthest from the halfway point of the pickup tubes can be used to optimize the clamping forces acting predominantly perpendicularly to the vertical axis H (X-direction) and the intermediate of three coupling elements at the inlet end and the intermediate of the three coupling elements at the outlet end - here, thus, the coupling elements 217b, 218b - can be used to optimize clamping forces acting predominantly in the direction of the vertical axis (Y-direction). Thus, for concrete measurement pickups, the optimum positions of the at least six coupling elements 217a, 217b, 217c, 218a, 218b, 218c can be found, once the wanted frequency band AFn for the internal oscillation system has been given, with very little effort experimentally and/or by means of computer-aided calculations, especially also simulations.
Also as a result of such investigations, a further embodiment of the invention provides that at least a first and second coupling element 217a, 217b of the coupling elements 217a, 217b, 217c connecting the two pickup tubes 4,5 together on the inlet end are each fixed to the intermediate tube segments 43,53 of the first and second pickup tubes 4,5 on the inlet end. Equally in the case of this embodiment of the invention, at least a first and second coupling element 218a, 218b of the coupling elements 218a, 218b, 218c connecting the two pickup tubes 4, 5 together on the outlet end are each fixed to the intermediate tube segments 45,55 of the first and second pickup tubes 4,5 on the outlet end. In another embodiment of the invention, additionally, at least a third coupling element 217c of the coupling elements 217a, 217b, 217c connecting the two pickup tubes 4, 5 together at the inlet end is fixed to the inlet tube segment 42, 52 of the first and second pickup tubes, and at least a third coupling element 218c of the coupling elements 218a, 218b, 218c connecting the two pickup tubes 4,5 together at the inlet end is fixed to the inlet tube segment 44, 54 of the first and second pickup tubes 4, 5.
17

We Claim:
1. Measurement pickup of vibration-type for measuring a flowable medium, especially a gas, liquid, powder or other flowable substance, conveyed in a pipeline, comprising:
- a pickup housing (10), which is mechanically coupled with the pipeline via an
inlet end and an outlet end;
-at least one first pickup tube (4, 5) held in an oscillatable manner in the pickup housing (10) and vibrating at least at times, and a second pickup tube (4, 5) mechanically coupled with the first pickup tube (4, 5) and likewise vibrating at least at times;
—wherein the first pickup tube (4) and the second pickup tube (5) execute during operation, at least at times, bending oscillations each about an imaginary oscillation axis essentially parallel to a longitudinal axis (L) of the measurement pickup, and
—wherein at least the first pickup tube (4) is embodied as a first measuring tube communicating with the pipeline and serving to convey the medium to be measured;
— an electromechanical, especially electrodynamic, exciter arrangement (60) acting
on at least one of the pickup tubes (4, 5) for producing and/or maintaining
mechanical oscillations of the at least one pickup tube (4, 5);
— a sensor arrangement reacting to movements at least of the first pickup tube (4),especially to bending oscillations, for producing at least one oscillation measurement signal (svb) representing oscillations of the first pickup tube (4); as well as
—at least three coupling elements (217a, 217b, 217c) connecting the first and the second pickup tubes (4, 5) together at their inlet ends, as well as at least three coupling elements (218a, 218b, 218c) connecting the first and the second pickup tubes (4, 5) together at their outlet ends.
2. Measurement pickup as claimed in the preceding claim, wherein the two pickuptubes (4, 5) oscillate during operation essentially with opposite phase.
3. Measurement pickup as claimed in one of the preceding claims, wherein each of the two pickup tubes (4) has an at least sectionally curved, especially essentially U-, V- or trapezoidally-shaped, central, middle tube segment (41,51).
4. Measurement pickup as claimed in claim 3, wherein the inlet-end coupling elements (217a, 217b, 217c) and the outlet-end coupling elements (218a, 218b, 218c) are so arranged and fixed on the two pickup tubes (4, 5) that those clamping forces produced by the vibrating pickup tubes (4,5) within the pickup housing are minimized, which act predominantly in the direction of that principal axis of inertia (H) of the measurement pickup, that runs essentially perpendicularly to the longitudinal axis (L) and that lies essentially in an imaginary central plane of the measurement pickup extending between the two curved middle tube segments (41, 51) of the pickup tubes (4, 5).
18

5. Measurement pickup as claimed in one of the claims 3 or 4, wherein each of the two pickup tubes (4) has at an inlet end a straight inlet tube segment (42, 52) extending essentially parallel to the imaginary oscillation axis, each inlet tube segment (42, 52) communicates with its middle tube segment via an inlet-end, curved, intermediate tube segment (43, 53) and wherein each of the two pickup tubes (4,5) has at an outlet end a straight outlet tube segment (44,54) extending essentially parallel to the imaginary oscillation axis and each outlet tube segment (44, 54) communicates with its middle tube segment (41, 51) via an outlet-end, curved, intermediate tube segment (45, 55).
6. Measurement pickup as claimed in claim 5, wherein at least one first and at least one second coupling element (217a, 217b) of the coupling elements (217a, 217b, 217c), connecting the two pickup tubes (4, 5) on the inlet end with one another, are each affixed to the inlet-end, intermediate tube segments (43, 53) of the first and second pickup tubes, and wherein at least one first and at least one second coupling element (218a, 218b) of the coupling elements (218a, 218b, 218c), connecting the two pickup tubes (4, 5) on the outlet end with one another, are each affixed to the outlet-end, intermediate tube segments (45,55) of the first and second pickup tubes (4, 5).
7. Measurement pickup as claimed in claim 6, wherein at least one, third coupling element (217c) of the coupling elements (217a, 217b, 217c) connecting the two pickup tubes (4,5) together on the inlet end is fixed to each of the inlet-end tube segments (42,52) of the first and second pickup tubes (4,5) and wherein at least one, third coupling element (218c) of the coupling elements (218a, 218b, 218c) connecting the two pickup tubes (4,5) together on the outlet end is fixed to each of the outlet-end tube segments (44,54) of the first and second pickup tubes (4, 5).
8. Measurement pickup as claimed in one of the preceding claims, wherein the first pickup tube (4) runs essentially parallel to the second pickup tube (5).
9. Measurement pickup as claimed in one of the preceding claims, wherein the first measurement pickup tube (4) is essentially constructed identically to the second measurement pickup tube (5).
10. Measurement pickup as claimed in one of the preceding claims, further comprising a first distributor piece (11) connecting the first and second pickup tubes (4, 5) together at the inlet end, as well as a second distributor piece (12) connecting the first and second pickup tubes (4, 5) together at the outlet end, wherein the second pickup tube likewise is constructed as a second measuring tube serving for the conveying of the medium to be measured and for communicating with the pipeline.
11. Measurement pickup as claimed in the preceding claim, wherein each of the two distributor pieces (11,12) has a mass of more than 10 kg, especially more than 20
kg-
19

12. Measurement pickup as claimed in one of the preceding claims, wherein the pickup housing (10) includes a support element (6), especially one of steel, with which the at least one pickup tube (4) is mechanically connected at its inlet and outlet ends.
13. Measurement pickup as claimed in the preceding claim, wherein the support element (6) is constructed in the form of a support cylinder, especially a tubular support cylinder, which is at least partially laterally open and connected with the at least one pickup tube (4) such that the at least one, curved tube segment (41) protrudes laterally out of the support cylinder.
14. Measurement pickup as claimed in the preceding claim, wherein the support element (6) has a mass of at least 70 kg, especially more than 140 kg, and/or a length of at least 1000 mm, especially of more than 1200 mm.
15. Measurement pickup as claimed in one of the preceding claims, wherein each of the pickup tubes (4, 5) and the pickup housing (10), is made, at least in part, of steel, especially stainless steel.
16. Measurement pickup as claimed in one of the preceding claims, wherein each of the pickup tubes (4, 5) has a mass of at least 10 kg, especially of greater than 25
kg-
17. Measurement pickup as claimed in one of the preceding claims, wherein each of the pickup tubes (4,5) has an inner diameter of at least 80 mm, especially greater than 100 mm.
18. Measurement pickup as claimed in one of the preceding claims, wherein each of the pickup tubes (4,5) has a cross section whose area moment of inertia is greater than 2 x 104 mm3, especially greater than 4 x 106 mm4.
19. Measurement pickup as claimed in one of the preceding claims, wherein each of the pickup tubes (4, 5) has a cross section whose section modulus resisting bending is greater than 106 mm4, especially greater than 2 x 106 mm4.
20. Measurement pickup as claimed in one of the preceding claims, wherein each of the pickup tubes (4, 5) has a stretched length of at least 1000 mm, especially greater than 1500 mm.
21. Measurement pickup as claimed in one of the claims 3 to 20, wherein each of the middle tube segments of the two pickup tubes (4, 5) has an essentially V-shape and wherein each of the middle tube segments of the two pickup tubes (4,5) has a peak with an included angle smaller than 150°, especially smaller than 120°.
22. Measurement pickup as claimed in one of the preceding claims, wherein an internal oscillation system of the measurement pickup is formed by the two pickup tubes (4,5), the medium at least instantaneously conveyed therein, and at
20

least in part by the exciter and sensor arrangements (60, 70), and wherein the internal oscillation system, driven by the exciter arrangement (60), executes during operation of the measurement pickup, at least at times, mechanical oscillations, especially in the form of lateral oscillations, with at least one wanted oscillation frequency (Fn), which depends both on the size, shape and material of the pickup tube (4) and on an instantaneous density of the medium, and which is changeable during operation of the measurement pickup, within a predetermined wanted frequency band (AFn) having upper and lower limit frequencies.
23. Measurement pickup as claimed in claim 22, wherein a total mass of the internal oscillation system amounts to at least 70 kg, and especially during operation, at least at times, to more than 90 kg.
24. Measurement pickup as claimed in one of the claims 10 to 21, wherein an external oscillation system of the measurement pickup is formed by the pickup housing and at least by the distributor pieces, while an internal oscillation system of the measurement pickup is formed by the two pickup tubes (4,5), the medium at least instantaneously conveyed therein and at least in part by the exciter and sensor arrangements (60, 70), and wherein the internal oscillation system, driven by the exciter arrangement (60), executes during operation of the measurement pickup, at least at times, mechanical oscillations, especially in the form of lateral oscillations, having at least one wanted oscillation frequency (Fn), which depends both on the size, shape and material of the pickup tube and on an instantaneous density of the medium, and which is changeable during operation of the measurement pickup within a predetermined wanted frequency band (AFn) having lower and upper limit frequencies.
25. Measurement pickup as claimed in claim 24, wherein a total mass of the external oscillation system amounts to at least 200 kg, especially more than 300 kg.
26. Measurement pickup as claimed in claim 24 or 25, wherein a mass ratio of a total mass of the external oscillation system to a total mass of the internal oscillation system is, during operation, at least at times, smaller than 3, especially smaller than 2.5.
27. Measurement pickup as claimed in the preceding claim, wherein the mass ratio of the total mass of the external oscillation system to the total mass of the internal oscillation system is continuously smaller than 3.
28. Measurement pickup as claimed in one of the preceding claims, wherein an installed mass to nominal diameter ratio of an installed mass of the total measurement pickup to a nominal diameter of the measurement pickup, which corresponds to a caliber of the pipeline in whose course the measurement pickup is to be installed, amounts to at least 1.5, especially more than 2.
21

29. Measurement pickup as claimed in one of the preceding claims, wherein the installed mass of the total measurement pickup is greater than 200 kg, especially greater than 400 kg.
30. Use of the measurement pickup as claimed in one of the preceding claims for measuring a flowable medium conveyed in a pipeline having a caliber greater than 150 mm, especially greater than 250 mm or more and/or for measuring a mass flowrate of a medium flowing through a pipeline with a rate which is, at least at times, greater than 900 t/h, especially, at least at times, greater than 1200 t/h


22

ABSTRACT
The measurement pickup includes a pickup housing (10), which exhibits a plurality of natural oscillation modes, as well as at least one first pickup tube (4) held oscillatably in the pickup housing (10), vibrating at least at times, and conveying at least a portion of the medium to be measured. Additionally, the measurement pickup includes an electromechanical, especially electrodynamic, exciter arrangement (60) acting on the at least one pickup tube for producing and/or maintaining mechanical oscillations of the at least one pickup tube (4), and a sensor arrangement reacting to movements of the pickup tube (4), especially bending oscillations, for producing at least one oscillation measurement signal (svb) representing oscillations of the pickup tube (4). Additionally, for improving the oscillation properties and, consequently, also the measurement accuracy of the measurement pickup, at least three coupling elements are provided for connecting the first and second pickup tubes (4,5) together at the inlet end, as well as at least three coupling elements (218) for connecting the first and second pickup tubes (4, 5) together at the outlet end. By using at least six coupling elements, it is possible to produce vibration-type measurement pickups of high measuring accuracy even at large nominal diameters of more than 150 mm, especially also while largely maintaining already established and proven forms of construction.
To,
The Controller of Patents,
The Patent Office,
23
Mumbai


Documents:

866-MUMNP-2007-ABSTRACT(06-11-2009).pdf

866-mumnp-2007-abstract(granted)-(22-1-2010).pdf

866-mumnp-2007-abstract.doc

866-mumnp-2007-abstract.pdf

866-MUMNP-2007-CANCELLED PAGES(06-11-2009).pdf

866-mumnp-2007-cancelled pages(6-11-2009).pdf

866-MUMNP-2007-CLAIMS(AMANDED)-(06-11-2009).pdf

866-mumnp-2007-claims(granted)-(22-1-2010).pdf

866-mumnp-2007-claims.doc

866-mumnp-2007-claims.pdf

866-MUMNP-2007-CORRESPONDENCE(22-1-2010).pdf

866-mumnp-2007-correspondence(24-7-2007).pdf

866-mumnp-2007-correspondence(ipo)-(25-1-2010).pdf

866-mumnp-2007-correspondence-received.pdf

866-mumnp-2007-descripiton (complete).pdf

866-MUMNP-2007-DESCRIPTION(COMPLETE)-(06-11-2009).pdf

866-mumnp-2007-description(granted)-(22-1-2010).pdf

866-MUMNP-2007-DRAWING(06-11-2009).pdf

866-mumnp-2007-drawing(granted)-(22-1-2010).pdf

866-mumnp-2007-drawings.pdf

866-MUMNP-2007-FORM 1(06-11-2009).pdf

866-mumnp-2007-form 2(06-11-2009).pdf

866-mumnp-2007-form 2(granted)-(22-1-2010).pdf

866-MUMNP-2007-FORM 2(TITLE PAGE)-(06-11-2009).pdf

866-mumnp-2007-form 2(title page)-(granted)-(22-1-2010).pdf

866-MUMNP-2007-FORM 3(06-11-2009).pdf

866-MUMNP-2007-FORM 3(22-1-2010).pdf

866-MUMNP-2007-FORM 5(06-11-2009).pdf

866-mumnp-2007-form-1.pdf

866-mumnp-2007-form-18.pdf

866-mumnp-2007-form-2.doc

866-mumnp-2007-form-2.pdf

866-mumnp-2007-form-26.pdf

866-mumnp-2007-form-3.pdf

866-mumnp-2007-form-5.pdf

866-MUMNP-2007-PCT-ISA-210(06-11-2009).pdf

866-mumnp-2007-pct-search report.pdf

866-MUMNP-2007-PETITION UNDER RULE 137(22-1-2010).pdf

866-MUMNP-2007-REPLY TO EXAMINATION REPORT(06-11-2009).pdf

866-mumnp-2007-wo international publication report(24-7-2007).pdf

abstract1.jpg


Patent Number 238191
Indian Patent Application Number 866/MUMNP/2007
PG Journal Number 5/2010
Publication Date 29-Jan-2010
Grant Date 22-Jan-2010
Date of Filing 11-Jun-2007
Name of Patentee ENDRESS + HAUSER FLOWTEC AG
Applicant Address KAEGENSTRASSE 7, CH-4153 REINACH.
Inventors:
# Inventor's Name Inventor's Address
1 SCHUETZE CHRISTIAN HABSBURGER STRASSE 34, CH-4055 BASEL.
2 ANKLIN - IMHOF MARTIN SAFFRETWEG 3B CH-4143 DORNACH
PCT International Classification Number G01F1/84
PCT International Application Number PCT/EP05/056328
PCT International Filing date 2005-11-29
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 102004060115.1 2004-12-13 Germany