Abstract: A Coriolis flowmeter having a single flow tube surrounded by connecting rings and a balance bar whose ends are connected by the connecting rings to the flow tube. The balance bar has a thermal coefficient of expansion greater than that of the connecting rings and the flow tube. The outer circumferential surface of each connecting ring is tapered toward the axial center of the flow tube. The inner circumferential surface of the balance bar has a taper matching that of the connecting ring. The connecting ring can only partially inserted into the space between the flow tube and the balance bar when the assembly is at room temperature. Braze material is then applied to the visible ends of the surface common to the balance bar and the connecting rings as well as to the ends of the surface common to the connecting rings and the flow tube. The structure is heated to brazing temperature to braze these common surfaces.

Abstract: A manufacturing process that prevents stress between a titanium flow tube and a surrounding steel balance bar due to a brazing operation. A straight tube Coriolis flowmeter having a titanium flow tube is surrounded by a balance bar having separate longitudinal halves. The balance bar halves are connected to each other by an elongated side channel on each side of the balance bar halves. The elongated side channels are radially spaced apart from the balance bar halves but connected to the balance bar halves by means of tubular pegs which extend into holes in the side channels. The flow tube is joined by brazing via connecting rings to the balance bar halves and to an inner end of the pegs. The radially outer end of the pegs are inserted into the holes in the side channels and welded. Circular welds and slots in the side channels reduce axial shrinkage of the side channels as the welds cool. This prevents axial stress on the flow tube.

Abstract: A Coriolis flowmeter having a single flow tube surrounded by connecting rings and a balance bar whose ends are connected by the connecting rings to the flow tube. The balance bar has a thermal coefficient of expansion greater than that of the connecting rings and the flow tube. The outer circumferential surface of each connecting ring is tapered toward the axial center of the flow tube. The inner circumferential surface of the balance bar has a taper matching that of the connecting ring. The connecting ring can only partially inserted into the space between the flow tube and the balance bar when the assembly is at room temperature. Braze material is then applied to the visible ends of the surface common to the balance bar and the connecting rings as well as to the ends of the surface common to the connecting rings and the flow tube. The structure is heated to brazing temperature to braze these common surfaces.

Abstract: Apparatus for and a method of operating a mass flowmeter having a first embodiment that uses gyroscopic forces to determine material flow information for a material flow. The interior of the flow tube defines a helix element that imparts a rotation to the material flow within the flow tube. Driver induced transverse flow tube vibrations and the rotation imparted to the material flow together generate cyclic gyroscopic forces within the flow tube. The magnitude of the flow tube deflection from the gyroscopic forces is related to the magnitude of the material flow and is measured to determine material flow information. A second embodiment of the flowmeter detect the Coriolis forces on the vibrating flow tube and generates material flow information from the detected Coriolis forces. The Coriolis based flow information and the gyroscopic based flow information are both applied to meter electronics which uses the two sets of Information for comparison and error checking and other purposes.

Abstract: A Coriolis flowmeter that uses a balance bar to allow stress in the active and inactive portions of the flow tube to be as low as possible for any thermal condition. The balance bar has a middle segment that is compliant in the axial direction so that changes in length of the balance bar ends do not impose a significant axial force on the flow lube. This ensures that the thermal stresses on the active and inactive portions of the flow tube are always equal. This state of stress equality is the lowest possible stress state for the flow lube. As a result of the axially compliant balance bar, the remaining stress in the flow tube is only a function of the differential expansion between the flow tube and the case. Balance bar expansion and contraction is eliminated and has no impact on the flow tube stress.

Abstract: Case connect links of a straight tube Coriolis flowmeter couple a balance bar/flow tube junction to the flow tube case. Each case connect link has at least one out of plane bend in its surface to allow the case connect link to expand/contract in response to temperature differentials between the internal elements of the flowmeter. The expansion/contraction permitted by the out of plane bend prevents structural damage to the case connect link as well as to the flowmeter elements to which it is connected.

Abstract: A balance bar for a straight tube Coriolis flowmeter. The balance bar is preferably manufactured by process that provides an increased number of flowmeter elements integral to the balance bar. These integral elements comprise: brace bars at each end of the balance bar, rib elements on each side of the balance bar to raise the horizontal vibration frequency, a surface to facilitate the mounting of a driver to the balance bar and to a flow tube surrounded by the balance bar, surfaces to facilitate the mounting of sensors to the balance bar and flow tube, voids that lower the resonant frequency of the balance bar in a drive plane, and a cavity that makes the vibration amplitude of the balance bar less than that of the flow tube. These elements lower the resonant frequency of the balance bar to make the flowmeter calibration factor independent of density. The balance bar is ideally made by a casting process. The balance bar may also be fabricated by other processes including machining.

Abstract: A single tube Coriolis flowmeter having a flow tube and balance bar vibrated in-phase opposition. Material flow through the vibrating flow tube induces Coriolis deflections in the flow tube which, via brace bars, induces in-phase Coriolis like deflection in the balance bar. A balance bar resonator coupled to the balance bar is excited to vibrate in a rotational mode out of phase with respect to the balance bar. The vibration of the balance bar resonator increases the accuracy of the flowmeter output data by 1) increasing meter flow sensitivity by applying torque to the balance bar to reduce its in-phase Coriolis like deflections; 2) by applying torque to the flow tube via the balance bar to reduce shaking of the flowmeter; and 3) causing the flowmeter to have a flat calibration factor with respect to changed in material density.

Abstract: A balance bar for a straight tube Coriolis flowmeter. The balance bar is preferably manufactured by process that provides an increased number of flowmeter elements integral to the balance bar. These integral elements comprise: brace bars at each end of the balance bar, rib elements on each side of the balance bar to raise the horizontal vibration frequency, a surface to facilitate the mounting of a driver to the balance bar and to a flow tube surrounded by the balance bar, surfaces to facilitate the mounting of sensors to the balance bar and flow tube, voids that lower the resonant frequency of the balance bar in a drive plane, and a cavity that makes the vibration amplitude of the balance bar less than that of the flow tube. These elements lower the resonant frequency of the balance bar to make the flowmeter calibration factor independent of density. The balance bar is ideally made by a casting process. The balance bar may be also fabricated by other processes including machining.

Abstract: A flowmeter having a case enclosing a single straight tube surrounded by a balance bar. The balance bar ends are coupled by means of a brace bar to the flow tube as well as by case connect links to the inner wall of the case. The flow tube ends are coupled to end flanges by means of a raised element having a center opening for sealably receiving the flow tube terminus. The flow tube projects beyond the case end and is sealably coupled to a cone connect element in the case end. A void is defined by the space between the flow tube outer surface and the inner surface of the cone connect element and the end flanges to minimize the surface area of the flow tube that is affected by the weld between the case end and raised element of the end flanges. The case connect links contain out of plane bends to accommodate a change in the effective diameter of the case and the balance bar with respect to each other due to changing thermal conditions.

Abstract: A flowmeter having a case enclosing a single straight tube surrounded by a balance bar. The balance bar ends are coupled by means of a brace bar to the flow tube as well as by case connect links to the inner wall of the case. The flow tube ends are coupled to end flanges by means of a raised element having a center opening for sealably receiving the flow tube terminus. The flow tube projects beyond the case end and is sealably coupled to a cone connect element in the case end. A void is defined by the space between the flow tube outer surface and the inner surface of the cone connect element and the end flanges to minimize the surface area of the flow tube that is affected by the weld between the case end and raised element of the end flanges. The case connect links contain out of plane bends to accommodate a change in the effective diameter of the case and the balance bar with respect to each other due to changing thermal conditions.

Abstract: Method and apparatus for providing compensation of mass flow rate and density for the flow tube of a single straight flow tube Coriolis flowmeter. Thermal stress compensation is provided by the use of a plurality of sensors on various portions of the flowmeter. A first sensor is coupled to the flow tube and provides information regarding the flow tube temperature. A plurality of additional sensors are connected to form a network having a two wire output. The additional sensors apply a composite signal over the two wire output of the network to meter electronics. The network signal represents the composite temperature of the flowmeter elements that can cause thermal stress on the flow tube when a temperature differential exists between the flow tube and the temperature of these plurality of elements. The additional elements include the balance bar and the flowmeter case. Sensitivity compensation is provided by the use of a novel algorithm.

Abstract: A balance bar for a straight tube Coriolis flowmeter. The balance bar is preferably manufactured by process that provides an increased number of flowmeter elements integral to the balance bar. These integral elements comprise: brace bars at each end of the balance bar, rib elements on each side of the balance bar to raise the horizontal vibration frequency, a surface to facilitate the mounting of a driver to the balance bar and to a flow tube surrounded by the balance bar, surfaces to facilitate the mounting of sensors to the balance bar and flow tube, voids that lower the resonant frequency of the balance bar in a drive plane, and a cavity that makes the vibration amplitude of the balance bar less than that of the flow tube. Said element that lowers the resonant frequency of the balance bar also makes the flowmeter calibration factor independent of density.

Abstract: A Coriolis flowmeter having a single straight flow tube, a balance bar parallel to said flow tube, a brace bar connecting ends of the balance bar to the flow tube and to a surrounding case. Improved dynamic balance of the flowmeter is maintained in response to changes in density of the flowing material by reducing the spring function of the balance bar and/or the flow tube. This concentrates the spring function of the flowmeter in the brace bar structure. A vibrational node in the brace bar structure separates the effective spring function of the balance bar from the effective spring function of the flow tube. The vibrational node moves within the brace bar in response to materials of different densities in the flow tube at different times. This nodal movement changes the ratio of the effective balance bar spring function to that of the effective flow tube spring function to maintain improved dynamic vibrational balance of the flowmeter without involving the case mass.

Abstract: A bypass flowmeter for measuring the material flow in a conduit. An optimum pressure drop is developed across the flowmeter by coupling the material outlet of the flowmeter to the throat of a venturi positioned within the conduit. This increased pressure drop improves the material flow rate through the flowmeter. This enhances flowmeter accuracy and sensitivity and the flowmeter's ability to measure mass flow rates for low density materials such as gas. The ratio of the material flow within the flowmeter to that of the conduit is derived with improved precision over prior arrangements which assume a constant ratio of material flow between the flowmeter and the conduit. The material flow information for the conduit is obtained for materials having a varying viscosity by the use of a differential pressure sensor which measures the pressure drop across the flowmeter and transmits this information to instrumentation which uses it to derive material flow information for the conduit with improved precision.

Abstract: A flowmeter positioned inside a case having compliant membranes for case ends. The membranes have an axial compliance sufficient to allow the flow tube to expand/contract freely in response to thermal changes without a permanent deformation of the flow tube.

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 Coriolis flowmeter whose flow tubes are made, at least part, of anisotrophic materials such as fiber reinforced composites. The composite material is formed by controllably orienting the fibers in one direction to increase the tensile strength of the material in that direction. Selected areas of the flow tubes are formed of this composite in order to increase the flowmeter sensitivity and to better separate the desired flowmeter vibrational frequencies from the undesired vibrational frequencies. Circumferentially oriented fibers increase the internal pressure containment capability of the flow tubes. A strain gauge affixed to the flow tube flexes with flow tube deformation to indicate the internal flow tube pressure.

Abstract: A Coriolis flowmeter having an outer rotor positioned within a housing and having a recess coaxial with a center axis of rotation. A Coriolis rotor is positioned in the recess of the outer rotor and has a center of rotation coaxial with the center axis of rotation. The Coriolis rotor has a plurality of holes, each of which extends from the outer periphery of said Coriolis rotor to a center recess of said Coriolis rotor. The outer rotor has a plurality of holes, each of which extends from the outer periphery of the outer rotor to the recess of said outer rotor with at least some of said holes in said outer rotor being aligned with a corresponding one of said plurality of said holes in said Coriolis rotor. A fluid inlet extends fluid through holes of both the outer rotor and the Coriolis rotor to a fluid outlet of the flowmeter. Both rotors rotate about the center axis of rotation when fluid is received and passes through the holes of the rotors.