Classifications

• • 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
  • G01F1/8472—Coriolis or gyroscopic mass flowmeters arrangements of measuring means, e.g., of measuring conduits vibrating measuring conduits having curved measuring conduits, i.e. whereby the measuring conduits' curved center line lies within a plane
  • G01F1/8477—Coriolis or gyroscopic mass flowmeters arrangements of measuring means, e.g., of measuring conduits vibrating measuring conduits having curved measuring conduits, i.e. whereby the measuring conduits' curved center line lies within a plane with multiple measuring conduits
• • 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
• • 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

Definitions

• a Coriolis mass flow meter is a device that measures the mass flow rate of a fluid passing therethrough generally by employing one or more vibrating tubes that carry the fluid to be measured.
• the moving mass of the flowing fluid in combination with the vibration of the tubes causes Coriolis forces to bare on those tubes, which alters their vibration pattern in a way that is measurable.
• the magnitude of this altered vibration pattern is proportionally related to the mass flow rate of the fluid.
• a balanced tube system is far more immune to the influence of ambient vibrations and far more immune to generating its own vibrations than a poorly balanced tube system. Therefore, it would be a great advancement in Coriolis flow measurement technology to disclose a method and apparatus to improve the balance of a Coriolis flow meter tube system that is immune to ambient vibrations.
• a solution for balancing a Coriolis mass flow meter involving the use of one or more balancing weights that may be sized and positioned to minimize or eliminate susceptibility to errors due to pipeline vibrations and changes in mounting conditions. Size and positioning of the one or more balancing weights may be determined by reaction forces at the base of a first flow tube and a second flow tube.
• a Coriolis flow meter may comprise a first flow tube having a first end and a second end. The first end may have a first reaction force, and the second end may have having a second reaction force.
• a second flow tube may be operably connected to the first flow tube.
• the second flow tube may have a first end and a second end. The first end may have a third reaction force, and the second end may have a fourth reaction force.
• a drive system may be operably connected to the first flow tube and the second flow tube.
• At least one balance mass may be operably attached the first flow tube or the second flow tube. The one balance mass may be sized and positioned to minimize one or more of the first reaction force, the second reaction force, the third reaction force, and the fourth reaction force.
• a method to balance a Coriolis mass flow meter tube structure may comprise the following steps: determining reaction forces in the x, y, and z direction at a base of a first flow tube and a second flow tube; combining the reaction forces; determining a first reaction force cancellation value; adding at least a first balance mass to the first flow tube at a first location and a second balance mass to the second flow tube at a second location; determining a second reaction force cancellation value; determining a change between the first reaction force cancellation value and the second force reaction cancellation value; and, calculating an optimized location and mass for the at least first balance mass and the at least second balance mass so that the change between the first reaction force cancellation value and the second force cancellation value is substantially zero.
• Figure 1 is an isometric view of an implementation of a device.
• Figure 2 is an isometric view of the device shown in FIGURE 1.
• Figure 3 is an isometric view of the device shown in FIGURES 1 and 2.
• Figure 4A is a graph of reaction forces vs. test mass location for a given balance analysis.
• Figure 4B is a graph of reaction forces vs. scaled test mass location for a given balance analysis.
• One implementation discloses both a method and apparatus to achieve improved balance for a Coriolis mass flow meter. This improved balance directly improves the accuracy of mass flow measurement especially in adverse field conditions where problems of ambient vibration of appurtenant pipes, structures, and equipment are present.
• the advantages of one implementation are achieved by first using a method to determine a specific mass value and one or more specified locations for that mass to be attached to the vibrating tube structure.
• This addition to the tube system is designed to minimize reaction forces at the connection point between the tube system and the body of the meter from both the normal driven vibration of the tubes, and by the altered vibration shape that is caused by the Coriolis forces.
• the vibrating tube system becomes highly immune from ambient vibrations entering the tube vibration system and causing measurement errors.
• less vibration energy is lost to the appurtenant structures and pipelines, which further reduces the meter’s susceptibility to zero or near zero stability errors.
• the flow tubes of Coriolis flow meters have taken many shapes and sizes.
• a simple U- shaped tube or tubes were used.
• Many shapes and sizes may be utilized including without limitation, straight tubes, S-shaped tubes, B-shaped tubes, omega shaped tubes, slightly bent tubes, and others.
• Coriolis flow meters have employed tubes or pipes ranging in size from less than 1mm in diameter to more than 12-inch diameter. The apparatus described herein has application to all of these tube shapes and sizes.
• Finite element analysis is an engineering software program used by Coriolis flow meter engineers to analyze the vibrations on a Coriolis tube meter structure 100.
• FEA can determine parameters such as tube frequency, deflection of any point on the tube, stress and strain along the tube, and reaction forces where the tubes are attached to the body of the meter, among others.
• a pair of tubes, each bent into a general U-shape are shown in Figure 1.
• the flow tubes 101 and 102 may be oriented in parallel, next to each other, and may be anchored to a heavier structure, typically a manifold casting (not shown), where the fluid may be split into two parallel streams, and conveyed into the tubes on the inlet side of the meter, and out of the tubes on the outlet side.
• Above the base of the tubes are connections between the tubes 101, 102, which may be brace-bars 103, 104 in one implementation.
• the brace-bars 103, 104 may link the two tubes 101, 102 together with a spring like connection to help them vibrate out of phase with each other in a balanced manner in a desired mode of vibration.
• a drive system 200 may be operably connected to the first flow tube 101 and the second flow tube 102.
• the drive system 200 may comprise a motion driving magnet 105 and motion driving coil 106.
• the motion driving magnet 105 may be operably connected to the first flow tube 101, and the driving coil 106 may be operably connected to the second flow tube 102.
• the motion driving magnet 105 and the driving coil 106 may be operably connected to the second flow tube 102 and the first flow tube 101, respectively.
• the motion driving magnet 105 and the motion driving coil 106 may be located at the top of the tubes near the center. The motion driving magnet 105 and the motion driving coil 106 are used to cause the requisite vibration by applying oscillatory forces on the tubes at a specified frequency to cause deflections in a specific mode or shape of vibration.
• the drive system 200 and its components may be positioned at the top of the flow tubes 101, 102 as shown in FIGURE 1.
• the drive system 200 may be disposed any place along the flow tubes 101, 102 chosen with sound engineering judgment, for example, the bottom of the tubes 101, 102.
• the flow tubes 101, 102 may be disposed below the manifold, and the drive system 200 and its components may be operably coupled to the flow tubes.
• additional structures may be included onto a tube structure design such as additional motion drivers, additional motion sensors, temperature sensors, accelerometers, and others. All these structures, which may be operably attached to the flow tubes 101, 102, may have an effect on the resulting vibratory motion of the tubes 101, 102, and on the balance and the reaction forces at the base of the tubes.
• the first flow tube 101 may have a first end 101a and a second end 101b.
• the second flow tube may have a first end 102a and a second end 102b.
• reaction forces 116, 117, and 118 are shown as forces at the base of one end of the tube 101 in the X, Y, and Z directions respectively.
• reaction forces 116a, 117a, and 118a can be measured proximate the base of the first end 101a of the first flow tube 101.
• reaction forces 116b, 117b, and 118b can be measured proximate the base of the first end 102a of the second flow tube 102.
• the reaction forces 116c, 117c, and 118c may be measured proximate the base of the second end 101b of the first flow tube 101.
• Reaction forces 116d, 117b, and 118d may be measured proximate the base of the second end 102b of the second flow tube 102.
• a first reaction force may be the resultant force of the reaction forces 116a, 117a, and 118a measured proximate the base of the first end 101a of the first flow tube.
• a second reaction force may be the resultant force of the reaction forces 116b, 117b, and 118b that may be measured proximate the base of the first end 102a of the second flow tube 102.
• a third reaction force may be the resultant force of the reaction forces 116c, 117c, and 118c measured proximate the base of the second end 101b of the first flow tube 101.
• a fourth reaction force may be the resultant force of the reaction forces 116d, 117d, and 118d measured proximate the base of the second end 102b of the second flow tube 102.
• the first reaction force, second reaction force, third reaction force and fourth reaction force may be defined any one of the locations proximate the base of the first flow tube 101 and the second flow tube 102.
• the first reaction force may be defined proximate the base of one of the flow tubes 101, 102 other than the first end 101a of the first flow tube 101.
• the second reaction force may be measured proximate the base of one of the flow tubes 101, 102 other than the first end 102a of the second flow tube 102.
• the tubes 101, 102 may have one or more of the masses 111, 112, 113, 114 attached thereto, and it may be helpful to match the masses of oppositely positioned structures on opposite tubes to improve balance. For example, it may be beneficial to match the mass of the motion driving magnet 105 to the mass of the motion driving coil 106. Similarly, it may be helpful to match the mass of the motion sensing magnets 107, 109 to the masses of their respective motion sensing coils 108, 110. However, this matching process may not result in an optimized balanced condition. The method of finding the optimized balanced condition will now be described with reference to Figure 3.
• Figure 3 shows the tube structure 100, which also includes balance masses 111, 112, 113, and 114.
• the mass magnitude and the location of the balance masses 111, 112, 113, 114 have been determined to minimize reaction forces 116, 117, and 118, or cancel these reaction forces with those from the other tube ends in the following way.
• the tube structure 100 may be designed to meet normal design specifications such as sensitivity to flow rate, size, weight, frequency, and other parameters. Once the tube structure 100 has met these example design parameters, it can be evaluated for proper balance by comparing the reaction forces 116, 117, 118 to the reaction forces on the other three tube ends to see if these forces cancel each other.
• reaction forces at the end of each tube can be determined, and mathematically added together to determine the degree of force cancellation. Normally, there will be found a resultant reaction force or forces that cause imbalance. This imbalance is difficult to avoid in the design process due to the complexity of the tube structure 100 and all of its appurtenant masses as previously described.
• Masses 111, 112, 113, and 114 are then added to the FEA model of the tube structure 100 at specified locations symmetrically about the XY plane, and the YZ plane 115 as shown. Reaction forces at the tube ends are then analyzed for cancellation of the reaction forces 116, 117, 118 with the forces from the other tube ends.
• a list of reaction forces as a function of balance mass magnitude and balance mass location can be determined and analyzed for an optimized balanced condition.
• the optimized balance condition may be achieved when all the specified reaction forces cancel for a specified mode of vibration or a specified deflected tube shape.
• reaction forces may be utilized for the dynamic balance method described herein.
• the first reaction force may be the only force needed for the calculation to minimize reaction forces.
• the first reaction force and the fourth reaction force may be used in the calculation.
• Figure 4A is a graph showing one example implementation where the reaction forces from the application of four symmetrically disposed test masses of 25 grams each as a function of test mass locations along the tube.
• the center of the graph at position zero is where the four test masses may be located at the top center of the tube where X-direction is zero according to the orientation triad 115.
• the graph shows finite reaction forces for four reactions, which are forces in the X- direction from the drive mode and the twist mode, and forces in the Y-direction from the drive mode and the twist mode. These four reaction forces do not converge to a zero result at any of the positions shown on the graph of Figure 4A.
• Figure 4B is the result of using an algorithm to scale the results of the test masses up to find the mass that minimizes the reaction forces.
• Figure 4B shows that at a scaled mass of 67 grams, the four reactions nearly converge to a best balance solution by placing 67 gram masses at locations +15 and -15 along the tube symmetrically from center.
• Figure 3 shows approximately the solution masses and their positions along the tubes.
• Figure 4A is a graph of reaction forces compared to test mass location for a given balance analysis using FEA results. Four reaction forces are shown not to converge to a best balance solution point.
• Figure 4B is a graph of reaction forces compared to scaled test mass location for a given balance analysis using FEA results. Four reaction forces are shown which nearly converge to a balanced solution point.
• the method may comprise the following steps. First, the first flow tube 101 and the second flow tube 102 may be vibrated in opposition to each other. Reaction forces 116a, 117a, and 118a in the x, y, and z direction proximate the base of the first end 101a and the reaction forces 116c, 117c, and 118c proximate the base of the second end 101b of the first flow tube 101 are determined.
• Reaction forces 116b, 117b, 118b proximate the base of the first end 102a of the second flow tube 102 and the reaction forces 116d, 117d, 118d proximate the base of the second end 102b of the second flow tube 102 are determined.
• a first reaction force cancellation value is determined. In one implementation, this may be a summation of the reaction forces proximate the base of each end of each flow tube.
• the first balance mass may be positioned to the first flow tube at a first location.
• the second balance mass may be positioned to the second flow tube at a second location.
• a second reaction force cancellation value is determined in a similar manner as the first reaction force calculation value. The first reaction force cancellation value and the second force reaction cancellation value are compared.
• the first balance mass and the second balance mass may maintain positions as it indicates a balanced Coriolis mass flow meter with minimal vibration effects. If the difference between the first reaction force calculation and the second reaction force calculation is not acceptable, the first balance mass and the second balance mass are moved. The steps of determining the reaction forces are successively repeated as many times as needed until the difference between the first reaction force and the second reaction force is zero, near zero, or at an acceptable level or number.
• a driven mode of vibration of the meter may be identified that may comprise the twist mode shape and the drive mode shape. Then the optimized balanced condition for the Coriolis flow meter may be found when all the reaction forces are minimized for the drive mode shape and the twist mode shape.
• the method may further comprise the step of positioning a plurality of balance masses on the first flow tube and the second flow tube such that the plurality of balance masses is axially and radially symmetrically positioned on the first flow tube and the second flow tube.
• any number of balance masses may be utilized with sound engineering judgment.
• two balance masses may be positioned on each fluid flow tube, which may comprise a first balance mass, a second balance mass, a third balance mass, and a fourth balance mass.
• each balance mass may be positioned and repositioned until the optimized location is found.
• each of the balance masses may be symmetrically positioned about the XY plane and the YZ plane.
• the word “exemplary” is used herein to mean serving as an example, instance or illustration. Any aspect or design described herein as “exemplary” is not necessarily to be construed as advantageous over other aspects or designs. Rather, use of the word exemplary is intended to present concepts in a concrete fashion.
• the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances.
• At least one of A and B and/or the like generally means A or B or both A and B.
• the articles “a” and “an” as used in this application and the appended claims may generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form.

Landscapes

• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Measuring Volume Flow (AREA)

Applications Claiming Priority (1)

Publications (2)

Family

ID=77491806

Family Applications (1)

Country Status (2)

Family Cites Families (10)

• 2020
  • 2020-02-26 EP EP20921225.7A patent/EP4111143A4/de not_active Withdrawn
  • 2020-02-26 WO PCT/US2020/019903 patent/WO2021173132A1/en not_active Ceased

Also Published As

Similar Documents

Legal Events