Abstract: An apparatus and method for determining frequency and phase relationships of vibrating flow tubes in a Coriolis mass flow meter. Adaptive line enhancement (ALE) techniques and apparatus are used in a digital signal processing (DSP) device to accurately determine frequency and phase relationships of the vibrating flow tube and to thereby more accurately determine mass flow rate of a material flowing through the mass flow meter. In a first embodiment, an adaptive notch filter is used to enhance the signal from each corresponding sensor signal on the vibrating flow tubes. In a second embodiment, a plurality of adaptive notch filters are cascaded to enhance the signal from each corresponding sensor signal. In both embodiments an anti-aliasing decimation filter associated with each sensor signal reduces the computational complexity by reducing the number of samples from a fixed frequency A/D sampling device associated with each sensor signal.

Abstract: An increased sensitivity Coriolis flowmeter having one or more drivers oscillates a flow tube, or tubes, at pre-determined frequencies thereby producing active and/or static nodes at points along the flowtube(s). The increased sensitivity of the present flowmeter is provided by controllably locating sensors in close proximity to the static nodes and/or active nodes. In a first embodiment, the flowtubes are oscillated in a manner generating a single active node with sensors positioned in close proximity to, and on opposing sides of, the active node. In a second embodiment, the flowtubes are oscillated in a manner generating multiple active nodes where the sensors are located on opposing sides of each active node, or on opposing flowtubes where one sensor is above an active node on one leg and a second sensor below the active node on the opposing leg. In another embodiment, sensors are positioned in close proximity to static nodes in addition to the sensor positions for active nodes as previously stated.

Abstract: A noise reduction system and method for measuring the phase difference between output signals of a Coriolis flowmeter. The output signals are applied to signal processing circuitry having three measurement channels, each of which includes a multi-pole filter having a relatively large phase shift. A channel pair is alternately switched in successive time intervals between a calibration status and an active status. In the calibration status, the two channels are connected during one time intervals to the same input signal and the output signals of the two channels are measured to determine the inherent phase delay between the two calibration channels. The two channels are then switched during the next time interval to an active status in which they are connected separately to the two output signals from the flowmeter.

Abstract: A Coriolis mass flow rate meter for measuring the mass flow rate of material flowing through a conduit. The flow meter includes at least one flow tube through which the material to be measured passes. The flow tube is vibrated at its natural frequency so that the concurrent flow of material through the vibrating tube produces a displacement of the tube with the magnitude of the displacement being dependent upon the magnitude of the generated Coriolis forces and the mass flow rate of the measured material. The phase of the displacement of the flow tube is measured using optical fiber sensors comprising at least one loop of optical fiber which is flexed by the displacement of the flow tube. This flexing of the fiber causes a corresponding change in its optical conductivity and a corresponding change in the intensity of the light transmitted through the fiber from a light signal source to a signal detector.

Abstract: A Coriolis mass flow rate meter for measuring the mass flow rate of material flowing through a conduit. The flow meter includes at least one flow tube through which the material to be measured passes. The flow tube is vibrated at its natural frequency so that the concurrent flow of material through the vibrating tube produces a displacement of the tube with the magnitude of the displacement being dependent upon the magnitude of the generated Coriolis forces and the mass flow rate of the measured material. The phase of the displacement of the flow tube is measured using optical fiber sensors comprising at least one loop of optical fiber which is flexed by the displacement of the flow tube. This flexing of the fiber causes a corresponding change in its optical conductivity and a corresponding change in the intensity of the light transmitted through the fiber from a light signal source to a signal detector.

Abstract: A Coriolis effect mass flow meter having a brace bar of improved flexibility which reduces the stress concentration in a brace bar as well as in areas of meter's flow tubes proximate the brace bar and flow tubes of the flow meter. A brace bar means is disclosed that has a void in an area between its holes that receive the flow tubes. This void increases the flexibility of the brace bar and shifts the concentration of operational and manufacturing induced stresses away from the braze joints between the brace bar and the flow tubes. The stresses are reduced and shifted away from the flow tubes to an area within the brace bar that is less critical to the overall life and reliability of the flow tubes. Meter sensitivity is improved due to enhanced flexibility of the present invention's brace bar in response to the motion induced by the Coriolis effect.

Abstract: A Coriolis flowmeter having a pair of parallel vibrating flow tubes equipped with a driver and sensors each comprising a fixed non-movable coil and a pair of magnets affixed to the vibrating flow tubes. Each coil magnetically cooperates with a unique pair of magnets. In a first embodiment, the coil is affixed to a non-movable member of the flowmeter. In another embodiment, the non-movable coil is affixed only to a spring sub-assembly which is affixed to the flow tubes which vibrate out-of-phase with respect to each other.

Abstract: Apparatus and accompanying methods for inclusion in a Coriolis meter that substantially eliminate temperature induced measurement errors which might otherwise be produced by performance differences existing between the separate input channels contained in the meter. Specifically, two pairs of input channels are used in the meter. In operation, the meter repetitively measures the internal phase delay of each of these pairs and then subtracts the delay associated with each pair from actual flow based measurement data subsequently obtained therefrom. While one channel pair is measuring actual flow, the other channel pair is measuring its internal phase delay, with the channels being continuously cycled between these functions.

Abstract: An optimized Coriolis mass flow meter is disclosed which has improved stability to excitations caused by external influences. A primary source of improvement involves determining by modal analysis of the flow conduit a location for the sensor means that minimizes the influence of external excitation of one or more of the first in phase bending mode, the first out of phase bending mode, the first out of phase twist mode, the second out of phase twist mode, the second out of phase bending mode and the third out of phase bending mode.

Abstract: Apparatus and accompanying methods for inclusion in a Coriolis meter that substantially eliminate temperature induced measurement errors which might otherwise be produced by performance differences existing between the separate input channels contained in the meter. Specifically, two pairs of input channels are used in the meter. In operation, the meter repetitively measures the internal phase delay of each of these pairs and then subtracts the delay associated with each pair from actual flow based measurement data subsequently obtained therefrom. While one channel pair is measuring actual flow, the other channel pair is measuring its internal phase delay, with the channels being continuously cycled between these functions.

Abstract: Apparatus and accompanying methods for inclusion in a Coriolis meter for measuring and updating a mechanical zero value for the meter using only zero flow measurements that have a sufficiently low noise content. Specifically, the meter produces zero flow measurements while no fluid is flowing through the meter. If a standard deviation of these zero flow measurements is less than a pre-defined limit value, then a resulting mechanical zero value, based on those measurements, is subsequently subtracted from the flow based measurement data.

Abstract: A Coriolis mass flow meter employing non-metallic flow conduit structure coupled and supported to distribute loads and reduce stresses on the flow conduit structure. The present invention discloses non-metallic flow conduit structures having corrosion-resistance and having suitable service temperature ranges, variation of Young's modulus and range of thermal expansion coefficient. A preferred embodiment includes support structures which distribute the loads on the flow conduit structure and pipe couplings which provide resilient solid mounting.

Abstract: An improved accuracy Coriolis mass flow meter. Signal processing embodiments provide improved accuracy by accounting for the non-linear relationship between phase angle difference of motion sensor signals and mass flow rate. Compensation is made for asymmetric and viscous damping effects, as well.

Abstract: A drive circuit for providing bursts, rather than continuously alternating amounts, of energy for use in driving a flow tube (conduit) in a Coriolis meter and methods for use in such a circuit. Specifically, the drive circuit provides a pre-defined burst of energy to a drive coil affixed to a flow conduit at an appropriate point during a cycle of the oscillatory motion of the conduit in order to maintain the peak amplitude of the oscillatory motion substantially within a prescribed range. This burst can be applied at a pre-defined point, illustratively the peak, in each cycle of the oscillatory motion with no energy being applied during that cycle other than when the pulse occurs in order to reduce the amount of electrical energy applied to the drive coil. Alternatively, to further reduce this energy, a burst need not be applied during every such cycle but rather only at those pre-defined points, e.g. the peaks, within those cycles where the velocity of the flow conduit is less than a pre-defined limit value.

Abstract: Apparatus and accompanying methods for use therein for a Coriolis mass flow rate meter which is substantially immune to noise, and more particularly, to such a meter that is substantially unaffected by noise that occurs at substantially any frequency different from a fundamental frequency at which the flow tube(s) in the meter vibrate. Specifically, the meter relies on measuring mass flow rate by determining the phase difference that occurs between real and imaginary components of the discrete fourier transform (DFT) of both the left and right velocity sensor waveforms evaluated at the fundamental frequency at which the flow tubes vibrate. The fundamental frequency is located, during an initialization operation, by providing a power spectrum, determined through use of the DFT of one of the sensor signals and then selecting that frequency at which the magnitude of the power spectrum reaches a maximum value.

Abstract: An apparatus comprising an insulated flexible circuit having conductors therein for electrically interconnecting vibrating structures having a half-loop shaped section between the structures so that the vibration does not cause fatigue and breaking of the conductors or insulation and which also minimizes coupling of mechanical forces between the structures that can alter vibrating motion of the structures. The flexible circuit apparatus is particularly useful for Coriolis type mass flow metering devices.

Abstract: Apparatus and accompanying methods for use therein for a Coriolis mass flow rate meter which is substantially immune to noise, and more particularly, to such a meter that is substantially unaffected by noise that occurs at substantially any frequency different from a fundamental frequency at which the flow tube(s) in the meter vibrate. Specifically, the meter relies on measuring mass flow rate by determining the phase difference that occurs between real and imaginary components of the discrete fourier transform (DFT) of both the left and right velocity sensor waveforms evaluated at the fundamental frequency at which the flow tubes vibrate. The fundamental frequency is located, during an initialization operation, by providing a power spectrum, determined through use of the DFT, of one of the sensor signals and then selecting that frequency at which the magnitude of the power spectrum reaches a maximum value.

Abstract: A Coriolis mass flow meter apparatus for determining the mass flow rates of fluids passed through twin flow tubes which are oscillated by a driver in a tuning fork fashion so as to be distorted by the mass flow rate of the fluid passing through the tubes with the distortion measured by sensors; where, sensor and driver components are mounted to each of the flow tubes so that the masses of the components and the structures used to mount the components to the flow tubes results in a center of gravity which is located on the axes about which each flow tube is distorted by generated Coriolis forces.

Abstract: Apparatus is disclosed for a Coriolis mass flow rate meter and specifically such a meter that is suited for operation at relatively high temperatures, such as in excess of approximately 500.degree. F. (approximately 260.degree. C.) and preferbly as high as 800.degree. F. (approximately 427.degree. C.), and that does not utilize a cooling purge.

Abstract: Test apparatus for proving the performance of Coriolis mass flow meters when measuring high-temperature fluid. Selected heat transfer fluid, preferably organic, is heated to the desired testing temperature and pumped from a fluid reservoir and heater through the meter being tested. A batch tank receives the fluid passing the meter and the tank is weighed before and after the test to prove the meter. All conduits connecting to the batch tank are flexible and the weighing scales operate with a minimum of deflection. An inert gas blanket is maintained in the fluid reservoir and the batch tank to maintain the selected organic fluid in a liquid state. The components of the apparatus are mounted on a platform and the apparatus can be easily transported for testing meters in the field.