MXPA01000513A - Improved vibrating conduit parameter sensors and methods of operation therefor utilizing spatial integration - Google Patents

Abstract

A process parameter sensor (5) for a material processing system (1) includes a conduit (103A-103B) configured to contain material from the material processing system. A plurality of motion transducers (105A-105D) is operative to produce a plurality of motion signals representing motion at a number of locations on the conduit. An overdetermined process parameter estimator (30) is responsive to the plurality of motion transducers and configured to receive the plurality of motion signals. The overdetermined process parameter estimator is operative to resolve conduit motion into motion attributable to each of a predetermined number of forces and to estimate a process parameter associated with a material in the conduit according to the resolved motion, wherein the number of locations exceeds the number of forces such that the plurality of motion signals provides an overdetermined information set for resolution of conduit motion into motion attributable to the predetermined number of forces.

Description

IMPROVED DETECTORS OF VIBRATORY DUCT PARAMETER. AND METHODS OF OPERATION FOR THEM USING INTEGRATION SPACE BACKGROUND OF THE INVENTION FIELD OF THE INVENTION This invention pertains to process parameter detectors and methods of operation therefor, and more particularly to vibratory duct parameter detectors and methods of operation therefor.

ESTABLISHMENT OF PROBLEM Coriolis effect mass flowmeters are commonly used to measure mass flow and other information for materials flowing through a conduit. Exemplary Coriolis flowmeters are described in U.S. Patent Nos. 4,109,524 of August 29, 1978, 4,491,025 of January 1, 1985 and Re. 31,450 of February 11, 1982, all to J.E. Smith et al. These flow meters typically include one or more conduits that have a straight or curved configuration. Each conduit can be observed constituted of a set of vibration modes that Ref: 126285 they include, for example, single, torsional, radial and coupled bending modes. In a typical mass flow measurement application, each conduit is driven to oscillate at a resonance in one of its natural modes as material flows through the conduit. The modes of vibration of the system filled with vibrating material are altered by the combined characteristics of mass and rigidity of the conduits as well as the characteristics of the material flowing within the conduits. A typical component of a Coriolis flowmeter is the drive system or gives excitation. The drive system works to apply a periodic physical force to the duct that causes the duct to oscillate. The drive system typically includes at least one actuator mounted to the conduit or conduits of the flow meter. The actuator typically contains one of many well-known electromechanical devices, such as a moving coil device having a magnet mounted on a first conduit and a fixed coil mounted on a second unit, in opposite relation to the magnet. A driving circuit simultaneously applies a periodic wave, for example sinusoidal or square, which drives a signal to the driving coil. The periodic driving signal causes the actuator to drive the two conduits in an opposite periodic pattern which is subsequently maintained.

When there is indeed a "zero" flow through a driven flowmeter conduit, the points along the conduit tend to oscillate approximately the same phase or a "zero flow" phase with respect to the impeller, depending on the vibration mode driven . As the material begins to flow from a flowmeter inlet, through the conduit and out of a flowmeter outlet, Coriolis material flow forces arise that tend to induce phase shifts between spatially separated points along the conduit. Generally, as the material flows through the conduit, the phase on the inlet side of the conduit delays the impeller, while the phase on the outlet side of the conduit advances to the impeller. The phase shifts induced between the two positions in the duct are approximately proportional to the mass flow rate of the material through the duct. To measure the mass flow rate, conventional Coriolis flowmeters typically measure the phase in two transducers, for example coil-type speed transducers, located near the respective ends of the conduit, positioned symmetrically with respect to the impeller placed centrally . However, the errors induced in the manufacturing in the placement of the transducer as well as other structural variations and deficiencies of Linearities in the structure of the conduit can cause impressions in the measurement.

BRIEF DESCRIPTION OF THE INVENTION In light of the above, an object of the present invention is to provide parameter detectors and methods of operation therefor which can provide more precise techniques for measuring process parameters such as mass flow rate, mass flow rate totalized, viscosity and similar in a vibratory duct parameter detector. These and other objective features and advantages of this invention are provided in accordance with this invention by a process parameter detector having a conduit through which material flows at an unknown flow velocity. An impeller is fixed to the conduit and applies a force to the conduit to cause the conduit to vibrate. N motion transducers are attached to the conduit at different points along the conduit and generate movement signals that represent the movement of the conduit at each different point, where N is an integer greater than one. The electronic measuring circuits receive the motion signals from the motion transducers and determine a process parameter. In a first aspect of this invention, a set of overdetermined process parameter estimator circuits is configured to receive the plurality of motion signals and separate the movable duct movement attributable to each of the M forces by determining a complex modal transformation of a complex eigenvector calibrated from of the plurality of movement signals. The calibrated complex eigenvector is a known rotation of a complex eigenvector associated with a drive mode at a known mass flow velocity of material. The complex modal transformation is a matrix which transforms the calibrated complex eigenvector to a rotation of the complex eigenvector associated with the drive mode for the unknown mass flow velocity of the material and to estimate a process parameter for the process processing system. material from the movement attributable to one of the forces M according to the complex modal transformation where M is at least one and less than N to provide overdetermined data. In another aspect of this invention, the parameter estimating circuits of overdetermined processes include a circuit (434) configured to generate an estimate of motion attributable to a Coriolis force and circuit (234) that respond to a generation of the motion estimate attributable to the Coriolis force, configured to generate an estimate of a process parameter from the estimate of movement attributable to such a Coriolis force. In another aspect of this invention, circuits configured to generate the estimate of a process parameter comprise circuits configured to generate a mass flow estimate. In another aspect of this invention, the overdetermined process parameter estimating circuits include circuits configured to combine a group of motion signals to produce a spatially mediated motion signal and circuits, which respond to a combination of such a group of motion signals, configured to generate an estimate of a process parameter from the spatially averaged motion signal. In another aspect of this invention, the circuits configured to generate an estimate of a process parameter comprise circuits configured to generate a mass flow estimate. In another aspect of this invention, the overdetermined process parameter estimator circuits are operative to separate movement of the conduit for movement in each of numerous real modes, and the N motion transducers are operative to produce a plurality of motion signals that represent the movement in N positions that exceed the number, M in modes real so that the N motion signals provide an overdetermined source of information for motion resolution in each of the real mode numbers. In another aspect of this invention, the overdetermined process parameter estimator circuits include circuits configured to generate a modal movement estimate attributable to a Coriolis force and circuits that respond to a generation of the modal movement estimate, configured to generate the estimate of a process parameter from the estimated modal movement. In another aspect of this invention, the overdetermined process parameter estimator circuits are operative to separate the movement of the conduit to motion in a complex mode, and the motion N-transducers are operative to produce N motion signals, a respective one of the N motion signals represent movement at a respective spatially different position in the conduit, in response to excitation, the number of positions exceeds two such that the plurality of motion signals provides an overdetermined source of information for motion resolution in the complex mode.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates one embodiment of a vibratory duct parameter detector according to the present invention. Figures 2 and 3 illustrate embodiments of a vibratory duct parameter detector that utilizes a complex modal estimate, in accordance with an aspect of the present invention. Figure 4 illustrates another embodiment of a vibratory duct parameter detector according to the present invention.

DETAILED DESCRIPTION OF THE MODALITIES The present invention will now be described more fully in the following with reference to the accompanying drawings to which the embodiments of the invention are shown. Those skilled in the art will appreciate that the invention can be constituted in many different ways and should not be considered as limited to the modalities set forth herein; rather, these embodiments are provided so that this description is considered deep and complete, and will present the full scope of the invention to those skilled in the art. In the drawings, numbers similar ones refer to similar elements through them. The following discussion relates to Coriolis flowmeters in which a process parameter of a material processing system is estimated, typically mass flow velocity for a material, for example, a fluid flowing through a vibratory conduit and configured to contain a material which passes through the vibratory duct as part of the material processing system. Those skilled in the art will appreciate, however, that the present invention is also applicable to vibration duct process parameter detectors other than in-line detectors. For example, in addition to on-line type mass flow meters, the present invention is applicable to sampling type vibratory tube densitometers which include a conduit configured to contain a sample of a material extracted from a processing system. material . As used herein, a "material processing system" may comprise a wide variety of fluid or other material handling systems in which the material is transported, contained, reacted or processed in some other way. These systems may include, but are not limited to, chemical and food processing systems, fluid transport systems such as oil pipes, hydraulic systems and the like. Figure 1 illustrates an exemplary embodiment of a parameter detector 5 according to the present invention. The detector 5 includes a conduit assembly 10. The conduit assembly 10 includes an inlet rim 101, an outlet rim 101 ', a manifold 102 and a first and second conduit 103A, 103B. Clamp bars 106, 106 'connect conduits 103A, 103B. Connected to the conduits 103A, 103B is an actuator 104 which is operative to vibrate the conduits 103A, 103B in response to an impeller 20. A plurality of motion transducers 105A-D is operative to produce motion signals that represent the movement of the conduits 103A, 103B in a plurality of positions thereof, for example signals representing displacement, velocity or acceleration. The motion transducers 105A-D may -include various devices, such as coil-type speed transducers, optical or ultrasonic motion detectors, accelerometers, inertial velocity detectors and the like. The conductors 100 are connected to the actuator 104 and to the motion transducers 105A-D. When the conduit assembly 10 is inserted into the material processing system 1, the material flowing in the material processing system 1 enters the conduit assembly 10 through inlet flange 101. The material then flows through the manifold 102, where it is directed to the interior of the conduits 103A, 103B. After leaving the conduits 103A, 103B, the material flows back into the manifold 102 and salts of the meter assembly 10 through the outlet rim 101 '. As the material flows through the conduits 103A, 103B, it gives rise to Coriolis forces that disturb the conduits 103A, 103B. The conduits 103A, 103B are typically driven by the actuator 104 in opposite directions around their respective bending axes WW and W'-W 'including what is commonly referred to as the first bending mode out of phase in the conduit assembly 10 . The actuator 104 may comprise any of many well-known devices, such as a linear actuator including a magnet mounted to the first conduit 103A and an opposite spool mounted in the second conduit 103B. An alternating current induced by a driving signal that is provided by an impeller 20 via the conductor 110 passes through the coil, generating a mechanical force that vibrates the conduits 103A, 103B. Although the parameter detector 5 illustrated in Figure 1 is shown with an integral actuator 104, those skilled in the art will appreciate that the vibration of the conduits 103A, 103B according to the present invention can be obtained by other techniques, for example by an excitation generated external to conduit assembly 10 and transported to conduit assembly 10, for example, via one of flanges 101, 101 '. An overdetermined process parameter estimator 30 responds to the plurality of motion transducers 105A-D, receiving motion signals on the conductors 111 which represent the movement of the conduits 103A, 103B as the material flows therethrough. The overdetermined process parameter estimator 30 processes received motion signals to separate movement of the moving conduit attributable to a predetermined plurality of forces acting on conduits 103A, 103B and including, for example, a Coriolis force imparted by a material passing through the conduits 103A, 103B and a force imparted by the actuator 104. The overdetermined process parameter estimator 30 is also operative to estimate a process parameter 35 associated with the material passing through the conduit, such as the mass flow velocity, totalized mass flow and the like, based on the separate movement. There are methods, devices and computer program products which use complex modal transformation estimates to generate mass flow estimates. The estimate can be generated by separating motion from moving detector duct attributable to Coriolis force and motion attributable to an aggregate of other forces. A example of this is shown in WO 97/40348 for Direct Measurement Corporation and WO 89/04463 for Flowtec AG. In particular, the Coriolis force is separated by determining the complexity introduced in the movement of a detector conduit by the mass flow through the conduit. An estimate of mass flow can be generated by estimating a complex modal transformation that is related to the mass flow. The use of the complex modal transformation is described in EP 0 791 807A for Flow Electronic Co., Ltd. Other measurement techniques can be considered using similar force resolution techniques. For example, measurement techniques which separate movement of the moving detector conduit in a plurality of real normal modes, i.e., movement of single-degree-of-freedom (SDOF) systems, can be considered to separate the movement of the respective moving conduit responding to forces in the respective SDOF systems. The separate movement in SDOF systems can be used to generate measurements of mass flow rate, total mass flow, viscosity and the like. For example, the separate movement in what is called the torsion mode of a Coriolis flowmeter having a U-shaped conduit can be assumed to be substantially attributable to Coriolis force produced by the moving material, and therefore, an estimate of the mass flow can be generated from an estimate of the movement in the torsion mode. The separation of movement in a force, such as the Coriolis force, is shown in WO 96/02812A which belongs to Micro Motion Ine. In accordance with the present invention, the estimator of process parameter is overdetermined, providing a mechanism to produce more accurate estimates of process parameters through spatial integration. As indicated above, the overdetermined process parameter estimator is operative to separate movement of the moving conduit attributable to a predetermined number of forces. As used herein, "overdetermined" means that the process parameter estimator is operative to generate an estimate of a process parameter from an overdetermined information source, i.e., a source that provides additional information that exceeds the minimum amount of information necessary to separate the movement in motion attributable to a predetermined number of forces. According to the present invention, motion signals are provided to the overdetermined process parameter estimator which represents the movement in several spatially diverse positions in the detector conduit that is greater than the number of forces to be separated, provided by a Source of information overdetermined spatially for the estimation process. The process parameter estimator therefore produces an estimated process parameter that is spatially integrated. The following discussion illustrates the use of spatially overdetermined datasets to generate process parameter estimates using complex modal estimation techniques. It will be understood that the spatial integration according to the present invention can be used with a variety of measurement techniques in addition to those that use complex modal estimation. For example, spatial estimation techniques described with reference to complex modal estimation are also generally applicable for measurement techniques that use real modal estimation. As also described herein, spatial integration can be used to combine information from spatially diverse transducers in a vibratory duct parameter detector, to form spatially-averaged motion signals that can be processed using, for example, Coriolis calculations of conventional phase difference types to provide improved measurements of process parameters such as mass flow rate, total mass flow, viscosity and the like.

Determination of Mass Flow Using Complex Modal Estimation A vibratory conduit of a parameter detector such as a Coriolis flow meter can be modeled as a system operating in a forced response state. The forced response can be modeled as a superposition of a plurality of real normal modal responses. According to such model, . { ? } = ff]. { ? } , (x) = [H]. { F.}. , Y . { ? } = [F] "1 [H] { F.}., [2) where . { ? } is a modal response vector,. { F.}. is a vector as a function of forced, [H] is a frequency response function matrix (FRF) and F x is the inverse of an F-shaped mode matrix. As you can see from equation (1), each term of the vector. { x} It has a phase associated with it. With zero flow through the conduit, the vector. { F.}. of force and the characteristics of the system constituted by the matrix [H] FRF are known, measuring the phase in any duct point will usually get the correct phase at any other point of the duct. The fluid that flows in a conduit can be represented as Coriolis forces which introduce complexity into a modal model of a conduit assembly. The Coriolis forces can be modeled using terms in the matrix associated with the velocity term in the linear differential equations that describe the movement of the detector conduit. When these Coriolis force terms are included in the proper value representation of the conduit, the eigenvectors, that is, the mode forms, become complex. In detail, the linear differential equations of the movements for the conduit become: [M] { x} + [C] (x) + [K] (x) =. { F.}. , (3) where [M] is a mass matrix, [K] is a stiffness matrix,. { F.}. is an applied force vector and [C] is a matrix of Coriolis forces acting on the velocity term. By including the Coriolis matrix [C], it introduces complexity to the problem of eigenvalue, that is, the results in complex eigenvectors. The movement of a conduit with a fluid flowing through it can be modeled as a scaled complex eigenvector. A complex own vector has two independent components in each degree of freedom. These components can include real and imaginary components or, alternatively, magnitude and phase components. According to this model, the movement of the conduit can be described by a free response, that is, the driving force can be neglected in the description of the movement. The movement of a discrete set of points. { x} in the conduit can be described by: where . { F} d is a complex eigenvector associated with drive mode,? d is a natural frequency associated with the drive mode and scaling the magnitudes of the eigenvector to match the operating amplitude. The assumption can be made that a. { | f | d} , the magnitude of the complex eigenvector. { F} d, is controlled by the driving circuit that drives the transducer to a given amplitude. Since ang (fd) is unknown the complexity of the eigenvector, the information about the movement in two positions can be used to determine the Coriolis forces. With reference to equation (2), the answer. { ? } complex modal involves the system characteristics, represented by the matrix [H] FRF, and the vector. { F.}. of applied force. The assumption that the vector is known can be established. { F.}. from applied force. However, the characteristics of the system, constituted in the matrix [H] FRF are a function of the mass flow velocity and therefore are unknown. Additional information, for example phase at a point other than the impeller, allows the determination of the mass flow velocity. In sum, the recognition of a complex movement from at least two positions provides sufficient information to separate movement of the moving duct attributable to Coriolis forces and movement attributable to other forces. A solution for measuring the mass flow can therefore include, for example, precisely controlling the amplitude in one position, for example, the driving position, so that the amplitude or phase of another position can provide sufficient information for a calculation of mass flow. Alternatively, the amplitude measured simultaneously in two separate positions, each amplitude measurement is normalized to a maximum amplitude in the position, and can provide sufficient information for a mass flow measurement. The complexity of a mode can be seen as a rotation of an eigenvector in the complex plane. Knowing the imaginary part of the eigenvector in either of the two positions can provide information regarding the complexity of mode shape, where the imaginary rotation It is related to the speed of mass flow. To estimate mass flow, for example, a meter is calibrated so that rotation is known, that is, a complex eigenvector in a known mass flow. An unknown mass flow determines a corresponding complex vector and assuming that this vector corresponds to a complex modal transformation of the calibrated complex self-vector. The transformation can be estimated from the calibrated complex eigenvector and the measurement vector using, for example, a curve fitting technique. The estimated transformation can then be used to estimate the unknown mass flow from the known mass flow. A generalized linear regression technique can be used to determine mass flow from complex modal measurements. For example, a vector. { Yß} of n x 1 elements can be constructed at a known mass flow rate; . { Yß} one can include, for example, phase measurements in a plurality of positions in a detector conduit. With material flowing through the conduit at an unknown mass flow rate, another element vector n x 1 can be constructed. { X.}. from complex measurements in the plurality of positions. As described above, complex values can be generated for. { Yß} Y . { X.}. using measurements different from the phase measurements.

When performing a linear regression, a transformation is found in such a way that: . { Y = a. { x} + b, (5) where a and b are constants that represent the slope and deviation, respectively. When manipulating equation (5): where [Z] is an augmented matrix constructed from. { x} Y . { c} is a vector that has a and b as first and second respective elements. Equation (6) is a form that allows the calculation of. { c} . According to the present invention, the number of positions for which movement information is available, for example, the number of positions of the transducer, exceeds the number of forces for which the movement of the conduit is to be separated, and thus both [Z] represents an overdetermined system, that is, [Z] has more rows that columns. In such an overdetermined case, equation (6) can be solved by premultiplying both sides by the transposition of [Z]: [Z] T { YE } = ([Z] T [Z]). { c} (7) [Z] T [Z] is a square matrix, which, for a well-established problem physically has an inverse. Premultiplying both sides of equation (7) by the inverse of [Z] T [Z] and by solving for. { c} : . { c} = ([Z] t [Z] -1 [Z] t {Y (8) The result . { c} represents the best fit of the vector. { X.}. for the complex eigenvector. { Yß} according to the least squares criterion. The first element of. { c} , the slope a, represents a scaling factor for a scaled rotation of. { X.}. to adjust with. { Y.} . For example, if they are built. { X.}. e. { Y.} from phase measurements, the mass flow velocity kd.BC? known to correspond to. { X.}. can be estimated from the known mass flow velocity k with the: k "known •• unknown" (9) Modal Detector Complex Overdetermined Figure 2 illustrates an embodiment of a parameter detector 5 that uses complex modal estimation according to the present invention. The conduits 103A, 103B of a conduit assembly 10 are energized by one or more actuators 104. A plurality of motion transducers 105A-D produce a plurality of motion signals in a plurality of movement line 111 represented in two or more positions. in conduits 103A, 103B. An overdetermined process parameter estimator 30 includes a complex modal transformation estimator 232 responsive to the plurality of motion transducers 105A-D, receiving the plurality of motion signals and estimating a complex modal transformation 233 therefrom. The estimated complex modal transformation 233 separates in motion from the moving conduit attributable to a Coriolis force and motion attributable to an aggregate of other forces by determining the complexity introduced in the movement of conduits 103A, 103B by a Coriolis force, as describe before. A process parameter estimator 234 responds to the generation of complex modal transformation 233 and generates an estimate 35 of a process parameter, for example the mass flow rate, the mass flow rate totalized, the viscosity and the like, associated with a material that happens to through conduits 103A, 103B from the estimated complex modal transformation 233. Because the number of positions for which motion information is provided exceeds the number of forces for which move is separated 13, the process parameter estimate 35 is spatially integrated. Figure 3 illustrates an exemplary embodiment of an overdetermined process parameter estimator. As illustrated, the complex modal transformation estimator 232 includes a sampler 332, for example a sampling and holding circuit or similar circuit, and an analog-to-digital converter (A / D) 334. The sampler 332 and the A / D converter 334 provide a means 331 for receiving the movement signals 333 of motion transducers, sampling the movement signals 333 and producing samples 333 thereof which are converted to digital signal values 335 by the analog to digital (A / D) converter 334. The detailed operations of the sampler 332 illustrated and the A / D converter 334 can be carried out by many circuits known to those skilled in the art and need not be discussed in more detail herein. Those skilled in the art will appreciate that the receiver means 331 illustrated in Figure 3 can be implemented in numerous ways, including additional pre-sampling, filtering against aliasing, post-sampling filtering and the like. It will also be understood that, in general, the receiver means 331 illustrated in Figure 3 can be implemented using essential purpose hardware, firmware or software that functions in general purpose data processing devices or combinations thereof. The portions of the complex modal transformation eliminator 232 can be constituted in a computer 50, for example a microprocessor, microcontroller, digital signal processor (DSP) or the like. For example, the computer 50 may comprise an online DSP suitable especially for linear algebraic calculations, such as one of the DSPs of the TMS320C4X family of the DSPs sold by Texas Instrument Inc. Configured with an appropriate program code, for example software or firmware or both and stored data, for example, in a storage medium 60 such as a random access memory (RAM) an electrically erasable programmable read-only memory (EEPROM), a magnetic disk or the like, the computer 50 provides an estimator 232 of complex modal transformation to estimate a complex modal transformation 233 from the digital values 335. The process parameter estimator 234 can also be increased in the computer 50. Constituted, for example as software or firmware running on the computer 50, the process parameter estimator 234 calculates an estimate 35 of a process parameter, for example calculate a unknown mass flow velocity from an unknown mass flux according to the estimated calculated complex modal transformation 233 produced by the complex modal transformation estimator 232. The spatial integration techniques described above with respect to the complex modal estimation are similarly applicable to techniques for estimating process parameters which use real modal estimation. In a manner analogous to the resolution described before duct movement in real and complex components, the movement of a detector duct in a plurality of real normal modes can be separated, for example multiple bending modes, torsion modes and the like, which represent the movement of the conduit as movement of a plurality of subsystems of a single degree of freedom (SDOF) subjected to respective force functions. Estimates of process parameters can be generated from the separate movements in each of the modes in a manner similar to that described above for complex modal estimation. The movement in the SDOF systems can then be combined in a weighted combination, for example, to identify Coriolis force imparted by material moving in a detector conduit, thereby allowing estimation of the mass flow.

Overdetermined Estimator Using Conventional Coriolis Measurement Techniques In accordance with another aspect of the present invention, the spatial integration concepts described above can also be combined with conventional Coriolis measurement techniques. An exemplary embodiment of a parameter detector 5 according to the present invention is illustrated in Figure 4. The parameter detector 5 includes a plurality of motion transducers 105A-D that produce motion signals that represent motion in an overdetermined plurality. of positions in conduits 103A-103B. In the illustrated embodiment, the respective groups 113A-113B of motion transducers are grouped around motion transducers are grouped around respective positions in the u-shaped conduits 103A-103B. The overdetermined process parameter estimator 30- includes a means 423A, 423B of multiple signal combination. The output signals produced by a group of transducers 113A, 113B are fed to a signal combining means 423A, 423A where the signals are combined to produce a spatially averaged signal 433A, 433B. Means 434 is provided to generate an estimate 35 of a process parameter from the spatially averaged motion signals 433A, 433B, such as - 2d - the conventional Coriolis measuring circuit as described in U.S. Patent RE31,450 for Smith, U.S. Patent 4,879,911 for Zolok and U.S. Patent 5,231,884 for Zolok. It will be appreciated that the signal combining means 433A, 433B and the process parameter estimate generation means 434 can generally be implemented using special purpose hardware, software or firmware that functions in general or special purpose computing devices, or combinations thereof. For example, the signal combining means 423A, 423B may comprise any of numerous analog combining circuits that are operative to produce an output signal representing a weighted combination of input signals, such as resistor networks, weighted adding amplifiers and Similar. The operations of these circuits are well known to those skilled in the art and do not need to be discussed in detail here. The signal combination means and the process parameter estimate generation means can alternatively be implemented in a digital domain, with the combination of motion signals and the generation of a process parameter estimate, for example a difference calculation of phase, which is present in a calculation device such as a microprocessor, digital signal processor (DSP) or the like. Those skilled in the art they will also appreciate that the spatial integration for process parameter measurem can be implemd by means other than the grouped manner illustrated in Fig. 4. For example, a number of transducers can be placed around the detector conduits 103A, 103B and The output of the signals is combined into a general-weighted signal combiner or equalizer to produce one or more signals which can be used to carry out the Coriolis measurem. The drawings and the specification of the presapplication describe embodim of the invon. Although specific terms are used, they are used in a generic and descriptive sense only and not for purposes of limitation. It is expected that persons skilled in the art can and do use or sell alternative modalities that are within the scope of the following claims, either literally or under the doctrine of equival. It is noted that in relation to this date, the best method known to the applicant to carry out the aforemoned invon, is that which is clear from the presdescription of the invon.

Claims (16)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A process parameter detector that has a conduit through which the material flows at an unknown flow rate, an impeller fixed to the conduit which applies a force to the conduit to cause the conduit to vibrate, N motion transducers that are fixed to the conduit at different points along the conduit and generate movement signals representing the movement of the conduit at each different point where N is an integer greater than one, and electronic measuring circuits that receive the movement signals of the transducers of movement and determine a process parameter, the electronic circuits are characterized because they include: * overdetermined process parameter estimator circuits, configured to receive the plurality of movement signals and separate the motion of moving conduit attributable to each of the M forces when determining a complex modal transformation of a self-complementary vector calibrated from a plurality of motion signals where the calibrated complex eigenvector is a rotation known from a complex eigenvector associated with a drive mode at a known mass flow velocity of material and the complex modal transformation is a matrix which transforms the calibrated complex eigenvector to a rotation of the complex eigenvector associated with the drive mode for the unknown mass flow rate of the material to estimate a process parameter for the material processing system from the movement attributable to one of the M forces, according to the complex modal transformation where M is at least one and less than N, to provide overdetermined data.

2. The detector according to claim 1, characterized in that the overdetermined process parameter estimating circuits comprise: circuits configured to generate an estimate of movement attributable to a Coriolis force; and circuits that respond to the generation of the estimate of movement attributable to the Coriolis force, configured to generate an estimate of a process parameter based on the estimate of movement attributable to the Coriolis force.

3. The detector according to claim 2, characterized in that the circuits configured to generate the estimate of a process parameter comprise circuits configured to generate a mass flow estimate.

4. The detector according to claim 1, characterized in that the overdetermined process parameter estimating circuits comprise: circuits configured to combine a group of motion signals to produce a spatially averaged motion signal; and circuits that respond to a combination of the group of signals in motion, configured to generate an estimate of a process parameter from the spatially averaged motion signal.

5. The detector - according to claim 4, characterized in that the circuits are configured to generate an estimate of a process parameter comprising circuits configured to generate a mass flow estimate.

6. The detector according to claim 1, characterized in that: - 3a - the overdetermined process parameter estimator circuits are operative to separate movement of the conduit to movement in each of several real modes; and wherein N motion transducers are operative to produce a plurality of motion signals representing movement in N positions exceeding number, M, of real modes so that the N motion signals provide an overdetermined source of information for resolution of movement in each of the different real modes.

7. The detector according to claim 6, characterized in that the overdetermined process parameter estimating circuits comprise: circuits configured to generate an estimate of the modal movement attributable to a Coriolis force; and circuits that respond to a generation of the estimated modal movement, configured to generate the estimate of a process parameter from the estimated modal movement.

8. The detector according to claim 1, characterized in that: the overdetermined process parameter estimator circuits are operative to separate movement of the movement conduit in a complex mode; and wherein the N motion transducers are operative to produce N motion signals, a respective one of the N motion signals represents the movement at a respective spatially different position in the conduit in response to the excitation, the number of positions exceeding two , so that the plurality of motion signals provides an overdetermined information source for motion resolution in the complex mode.

9. A method for determining a process parameter associated with a material flowing at an unknown flow velocity through a conduit that is driven to oscillate by an impeller from motion signals generated by N motion transducers fixed to the conduit in where N is an integer greater than one, the method is characterized in that it comprises the steps of: generating a complex modal transformation of the movement of the conduit from the motion signals received from the N motion transducers where the complex modal transformation is a transformation of a complex eigenvector calibrated from the plurality of motion signals and where the calibrated complex eigenvector is a known rotation of a complex eigenvector associated with a drive mode at a known mass flow velocity of material and the complex modal transformation is a matrix which transforms the eigenvector complex calibrated to a rotation of the complex eigenvector associated with the drive mode for the flow velocity of unknown mass of the material; and separating movement of the moving conduit attributable to each of the M forces of the complex modal transformation, where M is an integer that is at least one and smaller than N to provide overdetermined data for the complex modal transformation; and estimating a process parameter for the material processing system from the movement attributable to one of the M forces, according to the complex modal transformation.

10. The method according to claim 9, characterized in that the movement of the separator conduit includes the stage of estimating movement attributable to Coriolis force and wherein the stage of estimating the process parameter includes the step of estimating a process parameter from the estimated movement attributable to the Coriolis force.

11. The method according to claim 9, characterized in that the step of estimating the process parameter comprises the step of generating a mass flow estimate.

12. The method according to claim 9, characterized in that the step of estimating the process parameter comprises the steps of: combining a group of motion signals to produce a spatially averaged motion signal; and generating an estimate of a process parameter from the spatially averaged motion signal.

13. The method according to claim 12, characterized in that the step of estimating the process parameter comprises the step of generating an estimate of the mass flow.

14. The method according to claim 9, characterized in that the step of separating the movement of M forces comprises the step of identifying M real modes and wherein the movement signals represent movement in N positions where N exceeds the number, N of real modes so that motion signals represent a source of information overdetermined for movement separation of the moving conduit in each of the plurality of real modes.

15. The method according to claim 14, characterized in that the step of separating the movement attributable to each of the forces M comprises the step of: "generating an estimate of modal movement attributable to a Coriolis force, and in which the stage of estimation of the process parameter from the estimated modal movement.

16. The method according to claim 9, characterized in that the step of separating the movement attributable to each of the forces M comprises the step of identifying a complex mode, and wherein the movement signals represent movement in N positions that exceed two so that the plurality of motion signals provide an overdetermined source of information for resolution of the moving conduit in the complex mode.