Abstract: Circuitry that provides alternating current to a load from a unipolar power supply. A current source in the circuitry controls current applied to the load. A first switch and a second switch are connected between the load and the current source and allow current to flow from the current source to the load in a first direction responsive to the first switch and the second switch being closed. A third switch and a fourth switch connected between the load and the current source allow current to flow from the current source to the load in a second direction responsive to the third switch and the fourth switch being closed.

Abstract: A Coriolis flowmeter having flow tubes with corrugations in the dynamically active portion of the flow tubes. The corrugations increase the flexibility of the flow tubes so that they are more responsive to the generated Coriolis forces. This enhances the flowmeter sensitivity. Corrugations in a straight flow tube also reduce thermally induced stresses on the flow tube when its axial length is constrained by a surrounding case or balance bar to which the flow tube ends are affixed. Corrugations may be selectively positioned on the flow tube to control the flow tube vibrational response for the fundamental drive mode as well as harmonics thereof.

Abstract: A viscometer for improved sanitary measurement of the viscosity of industrial fluids. The present invention provides a viscometer integral with a flow meter or a viscometer than can be mounted onto an existing flow meter. The viscometer includes two adjacent parallel flow channels having relatively flat inner surfaces. A differential pressure element is mounted between the adjacent flow channels to sense the differential pressure between the fluid flow of the two channels. The differential pressure is input along with the mass flow rate and fluid density to calculate the fluid viscosity.

Abstract: A mass flowmeter has a flow tube inserted within the confines of a conduit containing a material flow. Mass flow information is derived for the material flow within the conduit by generating mass flow information for the material flowing within the smaller flow tube positioned within the conduit and then by adjusting the calculations for the flow tube to represent mass flow information for the conduit. In accordance with a first embodiment of the invention, a pressurized cover is positioned around the flow tube to isolate the exterior surface of the flow tube from the material in the conduit. The space between the exterior of the flow tube and the cover is pressurized to a pressure equal to that of the material in the conduit. Both sides of the flow tube walls are at the same pressure so that a flow tube comprised of thinner and more flexible material may be used.

Abstract: A method of brazing and apparatus therefor wherein two elements are bonded together using pre-formed fillet material. In accordance with a first alternative embodiment, the pre-formed fillet material comprises a depression formed on a first surface of one of the elements by a punching operation. The preformed fillet material also comprises a protrusion formed on a second surface opposite the depression formed by the punching operation. The invention also comprises a method of reducing bending stress in a Coriolis flow tube by bonding the flow tube and a brace bar with preformed fillet material.

Abstract: A Coriolis effect mass flowmeter for measuring mass material flow in a conduit. Elements of the meter are clamped directly onto an existing pipe or other conduit without diversion of the flow. The meter comprises a driver, such as a magnetostrictive driver, to oscillate a section of pipe between two supports. The driver is mounted on the pipe section at or near an anti-node of the second harmonic mode of the natural frequency of the pipe section. A sensor, such as an accelerometer, is mounted onto the pipe section at the node point of the second harmonic mode of the natural frequency of the pipe section during zero flow, (zero flow node point). The second sensor measures the amplitude of displacement of the zero flow node point due to the Coriolis effect forces from the mass of the material flowing through the oscillating pipe. This measurement is indicative of the mass flow rate of the material flowing through the pipe.

Abstract: A tube end preparing apparatus for precisely preparing the ends of tubes, including bent tubes. The apparatus includes a reference mechanism, a tube clamping mechanism, a cutting mechanism, and cutting head control mechanisms. The reference mechanism and tube clamping mechanism combine to precisely locate a flow tube with respect to defined reference indicia. The entire locating and clamping process not only provides accuracy and symmetry in aligning and clamping the flow tube relative to the desired reference indicia but can be accurately repeated with speed. The cutting mechanism includes a rotating cutting head mounted for longitudinal movement on a carriage. A control system controls the feeding movement of the carriage as the cutting head nears the end of the flow tube. A first stop mechanism causes a plunger to contact a micro-switch to stop the longitudinal movement of the carriage. A second stop uses a hard stop to prevent the carriage from overtravel due to momentum.

Abstract: Sample and hold circuits are used to detect a DC component of an AC signal on an amplifier's output to generate a feedback signal that is applied to the amplifier's input to cancel out a DC component of an AC input signal. The sample and hold circuits detect the peak excursions of the AC output signal and apply the stored peaks to averaging circuitry which determines the magnitude of the DC component of the output signal.

Abstract: Apparatus and accompanying methods for a custody transfer metering system, that illustratively utilizes a dual tube Coriolis mass flow rate meter and provides accurate totalized mass flow measurements and fault detection capability, are described. Specifically, this apparatus senses time differences occurring in the movement of both flow tubes. Four such time difference measurements are taken and combined in a pre-defined manner so as to eliminate differences appearing in the electrical characteristics of analog circuitry connected to each of two sensors used to detect tube movement and thereby to advantageously increase measurement accuracy. Mass flow rate of the fluid passing through the meter is determined, as a function of the combined time measurements, in terms of normalized mass and time units and thereafter converted into user specified mass units/unit time. The resulting converted value is used to compute totalized mass flow and to set and/or update various system outputs.

Abstract: Method and apparatus for determining Young's Modulus of a specimen by measuring the speed at which stress waves, either P-waves or S-waves, propagate therein. An embodiment of the apparatus includes two fixtures which are removably affixed to opposite ends of the specimen. A hammer having an accelerometer affixed to its head is used to strike the first fixture to produce stress waves in the specimen. A timing means starts counting in response to an output generated by the accelerometer when the hammer strikes the first fixture. A second accelerometer affixed to the second fixture detects the stress waves and generates an output which causes the timing means to stop counting. Further circuitry extracts the measured time, calculates a dispersion time delay based on material and length, and subtracts the dispersion time delay and a predetermined constant, both dependent on the material in the specimen, from the measured time to form a corrected transit time.

Abstract: Apparatus and accompanying methods are disclosed for use in a Coriolis mass flow rate meter for providing a mass flow rate signal that has a substantially reduced harmonic content. Specifically, this apparatus measures the Coriolis force induced time interval, .DELTA.t, by measuring the time intervals that occur between each of two measurement points situated on one, e.g. the right, position (or velocity) waveform and a reference point situated on the other, e.g. left, position (or velocity) waveform and which temporarily occurs between each of the two measurement points.

Abstract: Apparatus and accompanying methods for implementing both an accurate densimeter and a net oil computer utilizing a common Coriolis meter assembly is described. In essence, this apparatus measures density of an unknown fluid by first determining the period at which both flow tubes contained within a dual tube Coriolis meter oscillate while the unknown fluid passes therethrough. This apparatus then squares the result. Thereafter, the density of the unknown fluid is determined as a linear function that relates the squared tube period measurement for the unknown fluid, and squared tube period measurements and known density values for two known fluids, such as air and water, that have previously and successively passed through the meter during calibration. When used as a net oil computer, the inventive system obtains mass flow and temperature measurements from the same flow tubes.

Abstract: Apparatus and accompanying methods are disclosed herein for use in a Coriolis mass flow rate meter for producing an "absolute" frequency output. This method is illustratively implemented within a microcontroller through use of various software steps, two internal timers and one external gate. The frequency signal present on this output advantageously contains a number of pulses having an approximate 50% duty cycle over a relatively wide dynamic range wherein the number of such pulses occurring during any timing interval is proportional to the measured mass flow rate but without substantially any extraneous pulses that would otherwise occur due to nested interrupt processing. As such, use of such a frequency output advantageously ensures that internally and externally maintained totalized mass flow values will not substantially diverge, if at all, over time.

Abstract: A Coriolis mass flow meter apparatus, suitable for high temperature applications, wherein a preferred embodiment of the apparatus is comprised of two cantilever-mounted U-shaped flow tubes sinusoidally driven as the tines of a tuning fork by a drive mechanism mounted on standoff means attached to the flow conduits, with flow rates measured by velocity sensors mounted on suspension bars attached to the flow conduits. The flow conduits are encased in an inner thermal isolation partition wall structure containing apertures through which the suspension bars and standoff means protrude. A vented outer casing encloses the flow tube and partition wall structure, with insulation provided between the outer casing and the partition wall. Thermal control means are provided inside the space enclosed by the partition wall means. Gas cooling means are provided for the velocity sensors and drive mechanism. Flexible double wire structure means are provided to transmit the velocity sensor signals.