WO2005057131A9 - Coriolis-massedurchfluss-messgerät - Google Patents
Coriolis-massedurchfluss-messgerätInfo
- Publication number
- WO2005057131A9 WO2005057131A9 PCT/EP2004/053322 EP2004053322W WO2005057131A9 WO 2005057131 A9 WO2005057131 A9 WO 2005057131A9 EP 2004053322 W EP2004053322 W EP 2004053322W WO 2005057131 A9 WO2005057131 A9 WO 2005057131A9
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- mass flow
- value
- measuring tube
- intermediate value
- density
- Prior art date
Links
Classifications
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/78—Direct mass flowmeters
- G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
- G01F1/84—Coriolis or gyroscopic mass flowmeters
- G01F1/8409—Coriolis or gyroscopic mass flowmeters constructional details
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/78—Direct mass flowmeters
- G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
- G01F1/84—Coriolis or gyroscopic mass flowmeters
- G01F1/8409—Coriolis or gyroscopic mass flowmeters constructional details
- G01F1/8413—Coriolis or gyroscopic mass flowmeters constructional details means for influencing the flowmeter's motional or vibrational behaviour, e.g., conduit support or fixing means, or conduit attachments
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/78—Direct mass flowmeters
- G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
- G01F1/84—Coriolis or gyroscopic mass flowmeters
- G01F1/8409—Coriolis or gyroscopic mass flowmeters constructional details
- G01F1/8413—Coriolis or gyroscopic mass flowmeters constructional details means for influencing the flowmeter's motional or vibrational behaviour, e.g., conduit support or fixing means, or conduit attachments
- G01F1/8418—Coriolis or gyroscopic mass flowmeters constructional details means for influencing the flowmeter's motional or vibrational behaviour, e.g., conduit support or fixing means, or conduit attachments motion or vibration balancing means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/78—Direct mass flowmeters
- G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
- G01F1/84—Coriolis or gyroscopic mass flowmeters
- G01F1/8409—Coriolis or gyroscopic mass flowmeters constructional details
- G01F1/8422—Coriolis or gyroscopic mass flowmeters constructional details exciters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/78—Direct mass flowmeters
- G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
- G01F1/84—Coriolis or gyroscopic mass flowmeters
- G01F1/8409—Coriolis or gyroscopic mass flowmeters constructional details
- G01F1/8431—Coriolis or gyroscopic mass flowmeters constructional details electronic circuits
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/78—Direct mass flowmeters
- G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
- G01F1/84—Coriolis or gyroscopic mass flowmeters
- G01F1/8409—Coriolis or gyroscopic mass flowmeters constructional details
- G01F1/8436—Coriolis or gyroscopic mass flowmeters constructional details signal processing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/76—Devices for measuring mass flow of a fluid or a fluent solid material
- G01F1/78—Direct mass flowmeters
- G01F1/80—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted
- G01F1/84—Coriolis or gyroscopic mass flowmeters
- G01F1/845—Coriolis or gyroscopic mass flowmeters arrangements of measuring means, e.g., of measuring conduits
- G01F1/8468—Coriolis or gyroscopic mass flowmeters arrangements of measuring means, e.g., of measuring conduits vibrating measuring conduits
- G01F1/849—Coriolis or gyroscopic mass flowmeters arrangements of measuring means, e.g., of measuring conduits vibrating measuring conduits having straight measuring conduits
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
- G01F25/10—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N11/00—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties
- G01N11/10—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material
- G01N11/16—Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties by moving a body within the material by measuring damping effect upon oscillatory body
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N9/00—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity
- G01N9/002—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis
- G01N2009/006—Investigating density or specific gravity of materials; Analysing materials by determining density or specific gravity using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis vibrating tube, tuning fork
Definitions
- the invention relates to a Coriolis mass flow / density meter for a flowing in a pipeline, in particular. Two or more phases, medium and a method for generating a measured value representing a mass flow.
- Such measuring devices In process measurement and automation technology for measuring physical parameters of a fluid flowing in a pipeline, such as e.g. the mass flow rate, the density and / or the viscosity, often used such measuring devices, which by means of a vibration-type measuring sensor inserted into the course of the fluid-carrying pipeline and flowed through by the fluid during operation and a measuring and operating circuit connected to it, in the fluid reaction forces, e.g. Coriolis forces corresponding to the mass flow rate, inertia forces corresponding to the density or friction forces corresponding to the viscosity, etc., and derived from these, generate the respective mass flow rate, a measurement signal representing the respective viscosity and / or the respective density of the fluid.
- vibration type sensors are e.g.
- the sensors each comprise at least one measuring tube held in a, for example tubular or box-shaped, support frame with a curved or straight tube segment, which vibrate to generate the above-mentioned reaction forces, driven by an electro-mechanical excitation arrangement, during operation is left.
- the measuring sensors In order to detect vibrations of the pipe segment, especially on the inlet and outlet sides, the measuring sensors also each have a physical-electrical sensor arrangement which reacts to movements of the pipe segment.
- the measurement of the mass flow is based, for example, on the fact that the medium is allowed to flow through the measuring tube which is inserted into the pipeline and vibrates during operation, as a result of which the medium experiences Coriolis forces.
- the vibrations of the measuring tube are therefore detected by means of two vibration sensors of the aforementioned sensor arrangement which are spaced apart from one another along the measuring tube and converted into vibration measuring signals from whose mutual phase shift the mass flow is derived.
- a temperature of the fluid to be measured is usually suitably measured directly, for example by means of a temperature sensor arranged on the measuring tube. It can therefore be assumed without further ado that - even if not expressly described - the density and temperature of the medium are measured using modern Coriolis mass flowmeters, especially since they always approach the mass flow measurement to compensate for measurement errors due to fluctuating fluid density are moving, cf. in particular the already mentioned WO-A 02/37063, WO-A 99/39164, US-A 56 02 346 or also WO-A 00/36379.
- inhomogeneous media in particular two-phase or multi-phase fluids
- the vibration measurement signals derived from the vibrations of the measuring tube in particular the phase shift mentioned, despite the viscosity and Density in the individual fluid phases as well as the mass flow rate are kept practically constant and / or are taken into account accordingly, are subject to considerable fluctuations and can thus become completely unusable for the measurement of the respective physical parameter without remedial measures.
- Such inhomogeneous media can, for example, be liquids into which, as is practically unavoidable in metering or filling processes, a gas present in the pipeline, in particular air, is introduced or from which a dissolved fluid, e.g. Carbon dioxide, outgassing and leads to foam formation.
- a dissolved fluid e.g. Carbon dioxide, outgassing and leads to foam formation.
- Another example of such inhomogeneous media is wet or saturated steam.
- the measuring tubes can also be those with a curved tube shape, so that the problem cannot be solved even by adapting the installation position. It has also been shown here that the aforementioned falsifications of the measurement signal even when using a vertically installed, straight line Measuring tube can not be significantly reduced. In addition, the fluctuations of the measurement signal thus generated with flowing fluid cannot be prevented in this way either.
- the classifiers can be designed, for example, as a Kohonen map or neural network and the correction can be based either on a few parameters measured during operation, in particular the mass flow and density, and other features derived therefrom, or also using an interval of one or more oscillation periods Carry out vibration measurement signals.
- Such a classifier has, for example, the advantage that compared to conventional Coriolis mass flow / density meters on the sensor no or only very slight changes need to be made, be it the mechanical structure, the excitation arrangement or the operating circuit controlling it that are specially adapted to the specific application.
- the invention consists in a Coriolis mass flow meter, in particular Coriolis mass flow / density meter, for measuring a mass flow of a medium flowing in a pipeline, in particular a two-phase or multi-phase medium, which comprises Coriolis mass flow meter:
- At least one measuring tube inserted into the course of the pipeline and through which the medium flows during operation
- a carrier means which is fixed at an inlet end and an outlet end of the measuring tube and thus clamps it so that it can vibrate
- An excitation arrangement which sets the measuring tube in operation in mechanical vibrations, in particular bending vibrations,
- a first vibration measurement signal representing one-sided vibrations of the measuring tube
- a second vibration measurement signal representing outlet-side vibrations of the measuring tube
- the evaluation electronics generate the correction value using a second intermediate value derived from the first intermediate value, which represents a function value of a power function with the intermediate value as the basis and an exponential, especially rational one, which is less than zero.
- the invention consists in a method for generating a mass flow of a medium flowing in a pipeline representing the first measured value by means of a Coriolis mass flow meter, in particular a Coriolis mass flow / density meter, which method comprises the following steps:
- the correction value is derived from the first intermediate value, the second intermediate value, which represents a function value of a power function with the intermediate value as the base and an, especially rational, exponent, which is less than zero, and
- the evaluation electronics delivers a density measurement value, which is derived from the first and / or the second vibration measurement signal and represents a density of the medium
- the evaluation electronics also determine the correction value by means of the density measured value.
- the evaluation electronics determine a deviation of the density of the medium from a predetermined reference density by means of the density measured value.
- the evaluation electronics have a table memory in which digitized correction values dependent on the second intermediate value are stored, and the table memory supplies the correction value by means of a digital memory access address formed on the basis of the second intermediate value.
- this comprises the following further steps:
- An advantage of the invention is that in the Coriolis mass flow meter according to the invention compared to a conventional Coriolis mass flow meter, only minor changes, essentially limited to the firmware, have to be made only in the usually digital evaluation electronics, while both the sensor and Even when generating and preprocessing the vibration measurement signals, no or only minor changes are required.
- the vibration measurement signals can still be sampled with a usual sampling ratio of well below 100: 1, in particular approximately 10: 1.
- FIG. 1 shows a perspective view of a Coriolis mass flow measuring device used to generate a mass flow measurement
- FIG. 2 schematically shows, in the manner of a block diagram, a preferred embodiment of a measuring device electronics suitable for the Coriolis mass flow meter of FIG. 1,
- FIG. 3 shows a perspective view in a first side view of an exemplary embodiment of a vibration-type measuring sensor suitable for the Coriolis mass flow meter of FIG. 1,
- Fig. 4 shows the sensor of Fig. 3 in perspective in a second side view
- FIG. 5 shows an embodiment of an electro-mechanical excitation arrangement for the sensor of FIG. 3.
- the Coriolis mass flow measuring device 1 comprises a measuring sensor 10 of the vibration type and, as shown in FIG. 2, measuring device electronics 50 electrically connected to the measuring sensor 10. To accommodate the measuring device electronics 50, a sensor 10 is also attached from the outside Electronics housing 200 provided.
- Coriolis forces are generated in the fluid flowing therethrough by means of the sensor 10, which is excited by the measuring device electronics 50 in operation, which are dependent on the mass flow m and which are measurable on the sensor 10, that is to say sensor-detectable and electronically evaluable , act back.
- the Coriolis mass flow measurement device is also used to measure a density ⁇ of the flowing medium and to determine a density measurement value xß that currently represents the density ⁇ .
- the measuring device electronics 50 is also designed so that it operates a Coriolis mass flow measuring device 1 with a higher-level measurement processing unit, for example a programmable logic controller (PLC), a personal computer and / or a workstation, via data transmission system,
- a fieldbus system can exchange measurement and / or other operating data.
- the measuring device electronics 50 is designed in such a way that it can be supplied by an external energy supply, for example also via the aforementioned fieldbus system.
- the vibration measuring device is provided for coupling to a fieldbus the, in particular programmable, measuring device electronics 50 has a corresponding communication interface for data communication, for example for sending the measurement data to a higher-level programmable logic controller or a higher-level process control system.
- the measuring sensor 10 comprises at least one measuring tube 13 having an inlet end 11 and an outlet end 12 of predeterminable measuring tube lumen 13A which can be deformed elastically during operation and of a predefinable nominal diameter.
- Elastic deformation of the measuring tube lumen 13A here means that in order to generate Coriolis forces that are fluid and thus describe the fluid, a spatial shape and / or a spatial position of the measuring tube lumen 13A is changed cyclically, in particular periodically, within a range of elasticity of the measuring tube 13, cf. e.g. US-A 48 01 897, US-A 56 48 616, US-A 57 96 011 and / or US-A 60 06 609.
- the sensor in Embodiment includes only a single, straight measuring tube
- any of the Corioils mass flow sensors described in the prior art can be used to implement the invention instead of such a vibration type transducer, especially one of the bending vibration type with only or at least partially in a bending vibration mode vibrating, curved or straight measuring tube.
- vibration-type sensors with two curved measuring tubes through which the medium to be measured flows are described, for example, in EP-A 1 154 243, US-A 53 01 557, US-A 57 96 011 US-B 65 05 519 or WO-A 02/37063 are described in detail.
- WO-A 02/099363 WO-A 02/086426
- WO-A 95/16 897 US-A 56 02 345
- US-A 55 57 973 US-A 53 57 811.
- the material for the measuring tube 13 used is e.g. Titanium alloys particularly suitable. Instead of titanium alloys, other materials commonly used for such, in particular also for bent, measuring tubes, such as e.g. stainless steel, tantalum or zirconium etc. can be used.
- the measuring tube 13 which communicates in the usual way on the inlet side and outlet side with the pipeline supplying or discharging the fluid, is clamped in a rigid, especially rigid and torsionally rigid, support frame 14 so that it can vibrate.
- a rigid, especially rigid and torsionally rigid, support frame 14 instead of the box-shaped support frame 14 shown here, it is of course also possible to use other suitable carrier means, such as, for example, tubes running parallel or coaxially to the measuring tube.
- the support frame 14 is fixed on the measuring tube 13 on the inlet side by means of an inlet plate 213 and on the outlet side by means of an outlet plate 223, the latter both being pierced by corresponding extension pieces of the measuring tube 13.
- the support frame 14 has a first side plate 24 and a second side plate 34, which two side plates 24, 34 are each fixed to the inlet plate 213 and to the outlet plate 223 in such a way that they run practically parallel to the measuring tube 13 and are spaced apart therefrom are arranged, cf. Fig. 3.
- facing side surfaces of the two side plates 24, 34 are also parallel to each other.
- a longitudinal rod 25 is fixed to the side plates 24, 34, spaced apart from the measuring tube 13, which serves as a balancing mass which counteracts the vibrations of the measuring tube 13.
- the longitudinal rod 25 extends, as shown in FIG. 4, practically parallel to the entire oscillatable length of the measuring tube 13; however, this is not mandatory, the longitudinal bar 25 can of course also be made shorter, if necessary.
- the support frame 14 with the two side plates 24, 34, the inlet plate 213, the outlet plate 223 and the longitudinal rod 25 thus has a longitudinal center of gravity which runs practically parallel to a measuring tube central axis 13B virtually connecting the inlet end 11 and the
- the measuring tube 13 has a first flange 19 on the inlet side and a second flange 20 on the outlet side, cf. Fig. 1; instead of the flanges 19, 20, e.g. other pipe connection pieces for detachable connection to the pipe can also be formed, e.g. the so-called triclamp connections indicated in FIG. 3. If necessary, the measuring tube 13 can also be connected directly to the pipeline, e.g. be connected by means of welding or brazing etc.
- the measuring tube 13 is vibrated during operation of the measuring sensor 10, driven by an electro-mechanical excitation arrangement 16 coupled to the measuring tube, at a predefinable oscillation frequency, in particular a natural resonance frequency, in the so-called useful mode and thus in can be predetermined elastically deformed, the natural resonance frequency also being dependent on a density of the fluid.
- the vibrating measuring tube 13 is spatially, in particular laterally, deflected from a static idle position, as is customary in such transducer arrangements of the bending vibration type.
- the excitation arrangement 16 is used to generate an excitation force F exc acting on the measuring tube 13 by converting an electrical excitation power P eX c fed in by the measuring device electronics 50.
- the excitation power P ec serves practically only to compensate for the power component extracted from the vibration system via mechanical and fluid-internal friction.
- the excitation power P ⁇ ⁇ C is set as precisely as possible so that practically the vibrations of the measuring tube 13 in the useful mode, for example that of a basic resonance frequency, are maintained.
- the excitation arrangement 16 For the purpose of transmitting the excitation force F exc to the measuring tube 13, the excitation arrangement 16, as shown in FIG. 5, has a rigid, electromagnetically and / or electrodynamically driven lever arrangement 15 with a boom 154 fixed to the measuring tube 13 and with a yoke 163.
- the yoke 163 is also fixed to one end of the arm 154 at a distance from the measuring tube 13, in such a way that it is arranged above the measuring tube 13 and transversely to it.
- a metal disk, for example, which receives the measuring tube 13 in a bore can serve as the arm 154.
- the lever arrangement 15 is T-shaped and arranged, see. 5 shows that it acts on the measuring tube 13 approximately in the middle between the inlet and outlet ends 11, 12, as a result of which it experiences its greatest lateral deflection in the middle during operation.
- the fifth comprises a first excitation coil 26 and an associated first permanent magnetic armature 27 and a second excitation coil 36 and an associated second permanent magnetic armature 37.
- the two excitation coils, which are preferably connected electrically in series, for driving the lever arrangement 15 26, 36 are on both sides of the measuring tube 13 below the yoke 163 on the support frame 14, in particular releasably, fixed so that they interact with their associated armature 27 and 37 during operation. If necessary, the two excitation coils 26, 36 can of course also be connected in parallel with one another. As shown in FIGS.
- the two armatures 27, 37 are fixed to the yoke 163 so that they are spaced apart from one another in such a way that during operation of the sensor 10 the armature 27 is practically from a magnetic field of the excitation coil 26 and the armature 37 is practically from a magnetic field Exciter coil 36 passes through and is moved due to corresponding electrodynamic and / or electromagnetic force effects.
- the movements of the armatures 27, 37 generated by the magnetic fields of the excitation coils 26, 36 are transmitted from the yoke 163 and from the arm 154 to the measuring tube 13.
- These movements of the armatures 27, 37 are designed such that the yoke 163 is alternately deflected from its rest position in the direction of the side plate 24 or in the direction of the side plate 34.
- a corresponding axis of rotation of the lever arrangement 15 which is parallel to the already mentioned measuring tube center axis 13B can, for example, extend through the arm 154.
- the support frame 14 further comprises a holder 29 for the electromechanical excitation arrangement 16, in particular detachably connected to the side plates 24, 34, in particular for holding the excitation coils 26, 36 and possibly individual components of a magnetic brake arrangement 217 mentioned below.
- the senor 1 has a measuring tube and support frame surrounding the sensor housing 100, which protects them from harmful environmental influences.
- the sensor housing 100 is provided with a neck-like transition piece to which the electronics housing 200 housing the measuring device electronics 50 is fixed, cf. Fig. 1.
- the rotation of the measuring tube 13 can be designed such that a lateral deflection of the end of the arm 154 spaced from the measuring tube 13 is either the same or opposite to the lateral deflection of the measuring tube 13.
- the measuring tube 13 can therefore execute torsional vibrations in a first bending vibration torsion mode corresponding to the same direction or in a second bending vibration torsion mode corresponding to the opposite direction. Then the natural fundamental resonance frequency of the second bending vibration torsion mode of e.g. 900 Hz almost twice as high as that of the first bending vibration torsion mode.
- a magnetic brake arrangement 217 based on the eddy current principle is integrated in the excitation arrangement 16, which serves to stabilize the position of the mentioned axis of rotation.
- the magnetic brake arrangement 217 it can thus be ensured that the measuring tube 13 always vibrates in the second bending vibration torsion mode and thus any external disturbing influences on the measuring tube 13 do not lead to a spontaneous change to another, especially not to the first, bending vibration torsion mode. Details of such a magnetic brake arrangement are described in detail in US-A 60 06 609.
- the imaginary central axis 13B of the measuring tube is slightly deformed and thus spans not a plane but a slightly curved surface during the vibrations. Furthermore, a path curve lying in this area and described by the center point of the measuring tube center axis has the smallest curvature of all the path curves described by the measuring tube center axis.
- the measuring sensor 10 further comprises a sensor arrangement 60 which uses at least one first sensor 17 which reacts to vibrations of the measuring tube 13 to generate a first, in particular analog, vibration measurement signal s1 which represents this.
- the sensor 17 can be formed, for example, by means of a permanent magnetic armature, which is fixed to the measuring tube 13 and interacts with a sensor coil held by the support frame 14. Particularly suitable as sensors 17 are those which, based on the electrodynamic principle, detect a speed of the deflections of the measuring tube 13. However, acceleration-measuring electrodynamic or also path-measuring resistive or optical sensors can also be used. Of course, other sensors known to the person skilled in the art and suitable for the detection of such vibrations can also be used.
- the sensor arrangement 60 further comprises a second sensor 18, in particular identical to the first sensor 17, by means of which it supplies a second vibration measurement signal s2, which also represents vibrations of the measuring tube 13.
- the two sensors 17, 18 are spaced apart from one another along the measuring tube 13, in particular at an equal distance from the center of the measuring tube 13, in the measuring sensor 10 such that by means of the sensor arrangement 60 both the inlet side and the outlet side Vibrations of the measuring tube 13 are recorded locally and mapped into the corresponding vibration measurement signals s1 and s2.
- the first and possibly the second vibration measurement signal s1 or s2, which usually each have a signal frequency corresponding to a momentary vibration frequency of the measuring tube 13, are fed to the measuring device electronics 50, as shown in FIG. 2.
- the excitation arrangement 16 is fed by means of a likewise oscillating excitation current i exc of adjustable amplitude and of an adjustable excitation frequency f exc in such a way that the excitation coils 26, 36 flow through it during operation and in a corresponding manner those for movement the armature 27, 37 required magnetic fields are generated.
- the excitation current i exc can be sinusoidal or rectangular, for example.
- the excitation frequency f exc of the excitation current i exc is preferably selected and set in the measuring sensor shown in the exemplary embodiment so that the laterally oscillating measuring tube 13 oscillates as exclusively as possible in the second bending vibration torsion mode.
- the measuring device electronics 50 comprises a corresponding driver circuit 53 which is controlled by a frequency control signal YFM representing the excitation frequency f exc to be set and by an amplitude control signal y AM representing the amplitude of the excitation current i ec to be set .
- the driver circuit can be implemented, for example, by means of a voltage-controlled oscillator and a downstream voltage-to-current converter; Instead of an analog oscillator, for example, a numerically controlled digital oscillator can also be used to set the excitation current i exc .
- an amplitude control circuit 51 integrated in the measuring device electronics 50 can be used, which uses the instantaneous amplitude of at least one of the two sensor signals s ⁇ , s 2 and a corresponding constant or variable amplitude reference value Wi, the amplitude control signal YAM updated; if necessary, a momentary amplitude of the excitation current i exc can also be used to generate the amplitude control signal YAM.
- Such amplitude control circuits are also known to the person skilled in the art. As an example of such an amplitude control circuit, reference is once again made to Coriolis mass flow meters of the "PROMASS I" series. Their amplitude control circuit is preferably designed so that the lateral vibrations of the measuring tube 13 to a constant, that is, from
- Density, ⁇ , independent, amplitude can be controlled.
- the frequency control signal y FM can be supplied by a corresponding frequency control circuit 52, which updates this, for example, using at least the sensor signal Si and using a frequency-representative direct voltage that serves as a corresponding frequency reference value W 2 .
- the frequency control circuit 52 and the driver circuit 53 are preferably connected to form a phase control loop, which is used in the manner known to the person skilled in the art to use a phase difference measured between at least one of the sensor signals s ⁇ , s 2 and the one to be set or the excitation current i exc measured , the frequency control signal y F to constantly adjust to a current resonance frequency of the measuring tube 13.
- phase locked loops for operating measuring tubes at one of their mechanical resonance frequencies is described in detail, for example, in US Pat. No. 4,801,897.
- other frequency control circuits known to the person skilled in the art can also be used, as described, for example, in US Pat. No. 4,524,610 or US Pat. No. 4,801,897.
- the amplitude control circuit 51 and the frequency control circuit 52 are realized by means of a digital signal processor DSP provided in the measuring device electronics 50 and by means of program codes implemented accordingly and running therein.
- the program codes can, for example, be stored persistently or permanently in a non-volatile memory EEPROM of a microcomputer 55 which controls and / or monitors the signal processor and, when the signal processor DSP is started, in a volatile data memory RAM of the measuring device, for example integrated in the signal processor DSP -Electronics 50 can be loaded.
- Signal processors suitable for such applications are, for example, those of the type TMS320VC33, as are marketed by Texas Instruments Inc.
- At least the sensor signal Si and possibly also the sensor signal s 2 are to be converted into corresponding digital signals for processing in the signal processor DSP by means of corresponding analog-to-digital converters A / D, cf. see EP-A 866 319 in particular.
- control signals output by the signal processor such as the amplitude control signal y AM or the frequency control signal y F M, may need to be converted from digital to analog in a corresponding manner.
- the vibration measurement signals x s1 , x s2 are also fed to a measuring circuit 21 of the measuring device electronics.
- the measuring circuit 21 serves to determine a measured value corresponding to the mass flow to be measured in the manner known per se to the person skilled in the art on the basis of a phase difference detected between the two, possibly suitably conditioned, vibration measurement signals x s ⁇ , x S2 .
- Conventional, especially digital, measuring circuits can be used as measuring circuit 21 for this purpose, which determine the mass flow on the basis of the vibration measuring signals x s ⁇ , x S2 , cf.
- Suitable measuring circuits are used which measure phase and / or time differences between the vibration measurement signals x s - ⁇ , x s2 and evaluate them accordingly.
- the measuring circuit 21 can also be implemented by means of the signal processor DSP.
- the correction of the intermediate value X ' m can , on the one hand, be carried out using fewer, very easy-to-determine correction factors, which can be carried out directly by the operator measured parameters, in particular the measured density and the provisionally measured mass flow rate, can be derived.
- the correction can be carried out using the predetermined density measured value X ⁇ , and the predetermined intermediate value X ' m with a computational effort that is very small compared to the rather complex calculation methods mentioned at the beginning.
- a corresponding correction value XK is derived from the intermediate value X ' m by means of the evaluation electronics 2 and the mass flow measurement value X m is calculated using the correction value X ⁇ to the intermediate value X' m , especially digitally ,
- the correction can be carried out in a simple manner based on the functional equation
- the evaluation electronics for the intermediate value X 'm from a second intermediate value X 2, of a function value of a power function, X' m n, the intermediate value X 'm as a base and an, especially.
- Rational, n exponent represents that is less than zero, ie the second intermediate value X 2 is intended to have the functional relationship:
- K « is an adaptation or scaling of the coefficient of the intermediate value X 2 which is determined in advance, for example individually in the calibration of the Coriolis mass flow measuring device 1 or device-specific, and, for example in the non-volatile memory EEPROM , digtal can be saved.
- the exponent n is chosen to be greater than -1, for example - 0.5 or -0.25.
- the electronic evaluation system uses the density measured value xß and a predetermined or timely measured reference density value Kß, which is stored, for example, as a constant value when the Coriolis mass flow meter is started up or in the operation of can be transmitted externally to the Coriolis mass flow meter, a deviation ⁇ of the density ⁇ of the medium from a predetermined reference density is determined.
- the deviation ⁇ determined in this way is made with the second intermediate value X 2 based on the functional equation
- the reference density value Kß can be entered manually, for example on site or from a remote control room, or sent from an external density meter to the measuring device electronics, for example via fieldbus.
- the reference density value Kß is determined using a density measurement value X ⁇ .o also stored in the measuring device electronics, the stored density measurement value xß, o representing a density of the medium, which at homogeneous medium or when medium is assumed to be homogeneous.
- the density stored as the reference density value Kß Measured value xßo used for the subsequent correction of an intermediate value X ' m previously determined for inhomogeneous medium.
- This embodiment of the invention can be used in a particularly advantageous manner, for example in a metering or filling process in which, on the one hand, flow conditions in the measuring tube differ considerably from one another in a short time sequence, in particular also when the measuring tube is not completely filled, but in which on the other hand, primarily the mass flow totalized over an entire batch, but ultimately the total mass of the filled is of interest.
- the aforementioned functions, which serve to generate the mass flow measured value X m , symbolized by Eq. (1) to (4) can be at least partially implemented in an evaluation stage 54 of the measuring device electronics 50.
- the evaluation stage 54 can advantageously also be implemented, for example, by means of the signal processor DSP or, for example, also by means of the microcomputer 55 mentioned above.
- the evaluation electronics 2 also have a table memory in which a set of digital correction values X ⁇ , ⁇ determined beforehand, for example during the calibration of the Coriolis mass flow rate measuring device, is stored. These correction values X ⁇ ,, are accessed via a memory address derived by means of the currently valid second intermediate value X 2 .
- the correction value X ⁇ can be determined in a simple manner, for example, by comparing the currently determined intermediate value X 2 with corresponding default values for the intermediate value X 2 entered in the table memory and then reading out the correction value X ⁇ , ⁇ that is closest to the intermediate value X 2 coming default value corresponds.
- a programmable read-only memory ie an EPROM or an EEPROM, can serve as the table memory.
- the use of such a table memory has the advantage, among other things, that the correction value X ⁇ is available very quickly at runtime after the calculation of the intermediate value X 2 .
- the correction values X ⁇ , ⁇ entered in the table memory can be very precisely beforehand using a few calibration measurements, for example based on Eq. (2) and using the least squares method.
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- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Signal Processing (AREA)
- Measuring Volume Flow (AREA)
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP04804715A EP1692466A2 (de) | 2003-12-12 | 2004-12-07 | Coriolis-massedurchfluss-messgerät |
CA2547697A CA2547697C (en) | 2003-12-12 | 2004-12-07 | Coriolis mass-flow measuring device |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE10358663.6A DE10358663B4 (de) | 2003-12-12 | 2003-12-12 | Coriolis-Massedurchfluß-Meßgerät |
DE10358663.6 | 2003-12-12 | ||
DE200410007889 DE102004007889A1 (de) | 2004-02-17 | 2004-02-17 | Coriolis-Massedurchfluß-Meßgerät |
DE102004007889.0 | 2004-02-17 |
Publications (3)
Publication Number | Publication Date |
---|---|
WO2005057131A2 WO2005057131A2 (de) | 2005-06-23 |
WO2005057131A9 true WO2005057131A9 (de) | 2005-08-25 |
WO2005057131A3 WO2005057131A3 (de) | 2005-09-29 |
Family
ID=34680032
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2004/053323 WO2005057137A2 (de) | 2003-12-12 | 2004-12-07 | Coriolis-massedurchfluss-messgerät |
PCT/EP2004/053322 WO2005057131A2 (de) | 2003-12-12 | 2004-12-07 | Coriolis-massedurchfluss-messgerät |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/EP2004/053323 WO2005057137A2 (de) | 2003-12-12 | 2004-12-07 | Coriolis-massedurchfluss-messgerät |
Country Status (4)
Country | Link |
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EP (2) | EP1692467A2 (de) |
CA (2) | CA2547699C (de) |
RU (2) | RU2339007C2 (de) |
WO (2) | WO2005057137A2 (de) |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102005046319A1 (de) | 2005-09-27 | 2007-03-29 | Endress + Hauser Flowtec Ag | Verfahren zum Messen eines in einer Rohrleitung strömenden Mediums sowie Meßsystem dafür |
DE102012011932B4 (de) | 2012-06-18 | 2016-09-15 | Krohne Messtechnik Gmbh | Verfahren zum Betreiben eines Resonanzmesssystems und diesbezügliches Resonanzmesssystem |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4524610A (en) * | 1983-09-02 | 1985-06-25 | National Metal And Refining Company, Ltd. | In-line vibratory viscometer-densitometer |
US5796012A (en) * | 1996-09-19 | 1998-08-18 | Oval Corporation | Error correcting Coriolis flowmeter |
DE59904728D1 (de) * | 1998-12-11 | 2003-04-30 | Flowtec Ag | Coriolis-massedurchfluss-/dichtemesser |
-
2004
- 2004-12-07 RU RU2006124841/28A patent/RU2339007C2/ru not_active IP Right Cessation
- 2004-12-07 CA CA2547699A patent/CA2547699C/en not_active Expired - Fee Related
- 2004-12-07 EP EP04804716A patent/EP1692467A2/de not_active Withdrawn
- 2004-12-07 CA CA2547697A patent/CA2547697C/en not_active Expired - Fee Related
- 2004-12-07 EP EP04804715A patent/EP1692466A2/de not_active Withdrawn
- 2004-12-07 WO PCT/EP2004/053323 patent/WO2005057137A2/de active Application Filing
- 2004-12-07 RU RU2006124840/28A patent/RU2348012C2/ru not_active IP Right Cessation
- 2004-12-07 WO PCT/EP2004/053322 patent/WO2005057131A2/de active Application Filing
Also Published As
Publication number | Publication date |
---|---|
EP1692467A2 (de) | 2006-08-23 |
EP1692466A2 (de) | 2006-08-23 |
RU2006124841A (ru) | 2008-01-20 |
RU2348012C2 (ru) | 2009-02-27 |
CA2547697A1 (en) | 2005-06-23 |
CA2547699C (en) | 2011-05-17 |
RU2339007C2 (ru) | 2008-11-20 |
CA2547697C (en) | 2011-05-17 |
WO2005057137A3 (de) | 2005-09-29 |
WO2005057137A2 (de) | 2005-06-23 |
RU2006124840A (ru) | 2008-01-20 |
WO2005057137A9 (de) | 2005-10-27 |
WO2005057131A3 (de) | 2005-09-29 |
WO2005057131A2 (de) | 2005-06-23 |
CA2547699A1 (en) | 2005-06-23 |
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