Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
  • B01F25/00—Flow mixers; Mixers for falling materials, e.g. solid particles
  • B01F25/40—Static mixers
  • B01F25/42—Static mixers in which the mixing is affected by moving the components jointly in changing directions, e.g. in tubes provided with baffles or obstructions
• • 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
  • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
  • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
• • 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
  • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
  • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
  • G01F1/6842—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow with means for influencing the fluid flow
• • 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
  • G01F1/82—Direct mass flowmeters operating by measuring pressure, force, momentum, or frequency of a fluid flow to which a rotational movement has been imparted using a driven wheel as impeller and one or more other wheels or moving elements which are angularly restrained by a resilient member, e.g. spring member as the measuring device
• • 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
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F5/00—Measuring a proportion of the volume flow
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D7/00—Control of flow
  • G05D7/06—Control of flow characterised by the use of electric means
  • G05D7/0617—Control of flow characterised by the use of electric means specially adapted for fluid materials
  • G05D7/0629—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means
  • G05D7/0635—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on throttling means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
  • F15D—FLUID DYNAMICS, i.e. METHODS OR MEANS FOR INFLUENCING THE FLOW OF GASES OR LIQUIDS
  • F15D1/00—Influencing flow of fluids
  • F15D1/001—Flow of fluid from conduits such as pipes, sleeves, tubes, with equal distribution of fluid flow over the evacuation surface

Definitions

• the present invention relates generally to the operation of a mass flow controller (MFC) or a mass flo meter (MF ),
• fluid is used herein to describe any type of matter in any state that is capable of flow.
• fluid may apply to liquids, gases, vapors, and slurries comprising airy combination of matter or substance to which controlled flow may be of interest.
• the disclosed embodiment seek to provide one or more solutions to the above problems, in particular, the inventors determined that most of the non-linearity is due to entrance affects at the bypass inlet. Thus, the inventors recognized that any improvement in bypass linearity is valuable because it will improve accuracy on process gas and improve the range of the instrument. BRIEF DESCRIPTION OF THE DRAWINGS
• Figure 1 is a diagram that illustrates components of a mass flow controller in accordance with the disclosed embodiments
• FIG. 1 is a diagram that depicts the speed contour of a flow meter device without an inlet mesh irt accordance with the disclosed embodiments;
• Figure IB is a diagram that depicts the speed contour of a flow meter device with an inlet mesh in accordance with the disclosed embodiments
• FIG. 2 is a diagram that illustrates a turning vane with a flow mixer in accordance with the disclosed embodiments
• Figure 3 is a diagram that illustrates the turning vane of Figure 2 in an assembly in accordance with the disclosed embodiments
• Figure 4A is a diagram that depicts the speed contour of a flow meter device that does not have a turning vane and mixer in accordance with the disclosed embodiments;
• FIG. 4B is a diagram that depicts the speed contour of a flow meter device that includes a turning vane and mixer in accordance with the disclosed embodiments;
• Figure 5A is a diagram that depicts the pressure con tour of a flow meter device that does not have a turning vane and mixer in accordance with the disclosed embodiments;
• FIG. 5B is a diagram that depicts the pressure contour of a flow meter device that includes a turning vane and mixer in accordance with the disclosed embodiments;
• Figure 6 is a graph depicting the difference in turndown between a flow meter device with a bypass mesh versus a flow meter with a bypass mesh plus a turning vane and mixer in accordance with the disclosed embodiments;
• Figure 7 is a diagram that illustrates an example of a turning vane in accordance with the disclosed embodiments.
• Figure 8 is a diagram that illustrates another example of a turning vane in accordance with the disclosed embodiments.
• Figures 9A-9E are diagrams that illustrate various configurations of a turning vane in an assembly in. accordance with the disclosed embodiments; and
• Figures 10A and 10B illustrate, yet another example of a turning vane in an assembly in accordance with the disclosed embodiments.
• FIG. 1 illustrates components of a mass flo controller 100 in accordance with the disclosed embodiments.
• Mass flow controller 100 includes a step 1 1 , which is the platform on which the components of the mass flow controller are mounted.
• a thermal mass flow meter 140 and a valve assembly 150 are mounted on the step 110 between a fluid inlet 120 and a fluid outlet 130.
• the valve assembl 150 includes a control valve ⁇ 70.
• the thermal mass flow meter 140 includes a bypass 142 through which typically a majority of fluid flows and a thermal flow sensor 146 through which a smaller portion of the fluid flows.
• Thermal flow sensor 146 is contained within a sensor bousing 102 (portion shown removed to show sensor .146 ⁇ mounted on a mounting plate or base 1 8.
• Sensor 146 is a small diameter tube, typically referred to as a capillary tube, with a sensor inlet portion 146 A, a sensor outlet portion 146B, and a sensor measuring portion I 46C about which two resistive coils or windings 147, 148 are disposed, in operation, electrical current is provided to the two resistive windings 147 tone .148, which are in thermal contact with the sensor measuring portion 146C.
• the current in the resistive windings 147, 148 heats the fluid flowing in measuring portion 146 to a temperature above that of the fluid flowing through the bypass 142,
• the resistance of windings 147, 148 varies with temperature.
• beat is carried from the upstream resistor 147 toward the downstream resistor 148, with the temperature difference being proportional to the mass flow rate through the sensor.
• An electrical signal related to the fluid flow through the sensor is derived from: the two resistive windings 147,148,
• the electrical signal may be derived in a number of different ways, such as from the difference in the resistance of the resistive windings or from a difference in the amount of energ provided to each resistive winding to maintain each winding at a particular temperature. Examples of various ways in which an electrical signal correlating to the flow rate of a fluid io a thermal m ss flow meter may he determined are described, for example, in commonly owned U.S. Pat. No. 6,845,659, which is hereby incorporated by reference.
• the electrical signals derived from the resistive windings 147,148 after signal processing comprise a sensor output signal.
• the sensor output signal is correlated to mass flow in the mass flow meter so that the fluid flow can be determined when the electrical signal is measured.
• the sensor output signal is typically first correlated to the flow in sensor 146, which is then correlated to the mass flow in the bypass 142, so that the total flow through the flow meter can be determined and the control valve 170 can be controlled accordingly.
• the correlation between the sensor output signal and the fluid flow is complex arid depends on a number of operating conditions including Bind species, flow rate, inlet and/or outlet pressure, temperature, etc.
• a bypass 142 may then be mounted to the sensor, and the bypass 142 is tuned with the known fluid to determine an appropriate relationship between fluid flowing in the mass flow sensor and the fluid flowing in the bypass at various known flow rates, so that the total flow through the flow meter can be determined from the sensor output: signal in some mass flow controllers, no bypass is used, and the entire flow passes through the sensor.
• the mass flow sensor portion and bypass 142 may then be mated to the control valve and control electronics portions and then tuned again, under known conditions.
• the responses of the control electronics and the control valve are then characterized so that the overall response of the system to a change in set point or input pressure is known, and the response can be used to control the system to provide the desired response.
• the mass flow cootrolicr 100 may incliide a pressure transducer 1 12 coupled to flow path at some point, typically, but not limited to, upstream of the bypass 142 to measure pressure in the flow path.
• Pressure transducer 112 provides a pressure signal indicative of the pressure.
• Control electronics 1 0 control the position of the control val ve 1 70 in accordance with a set point indicating the desired mass flow rate, and an electrical flow signal from the mass flow sensor indicative of the actual mass flow rate of the fluid flowing in the sensor conduit.
• Traditional feedback control methods such as proportional control, integral control, proportional-integral (PI) control, derivative control, proportional-derivative (PD) control, integral-derivative (ID) control, and proportional-integral -derivative (PID) control are then used to control the flow of fluid in the mass flow controller.
• a control signal (e.g., a control valve drive signal) is generated based upon an error signal that is the difference between a set point signal indicative of the desired mass flow rate of the fluid and a feedback signal that is related to the actual mass flow rate sensed by the mass flow sensor.
• the control valve is -positioned, in the main fluid, flow path (typically downstream of the bypass and mass flow sensor) and can be controlled (e.g., opened or closed) to vary the mass flo rate of fluid flowing through the main fluid flow path, the control being provided by the mass flo controller.
• the flow rate is supplied by electrical conductors 158 to a closed loop system, controller 160 as a voltage signal
• the signal is amplified, processed and supplied using electrical conductors 159 to the valve assembly 150 to modify the flow.
• the controller 160 compares the signal from the mass flow sensor 140 to predetermined value and adjusts the control valve 170 accordingly to achieve the desired flow.
• Figure 1 depicts that the mass flow controller 100 includes a thermal mass flow sensor
• the mas flow controller 100 in accordance with the disclosed embodiments, may utilize other types of mass flow sensors including a Coriolis type sensor.
• An advantage of using a Coriolis-based sensor is that it is capable of determining mass flow independent of temperature, flow profile, density, viscosity, and homogeneity.
• a mass flow meter differs from a mass flow controller, as described above, in that it lacks the control functions, instead, the mass flow meter is used merely to measure or determine fluid flow rate.
• the disclosed embodiments seek to improve bypass linearity because doing so will improve accuracy on process gas and improve the range of the instrument.
• the term "turndown" is used as a measurement of the linearity of the bypass design, it is defined as the total flow at 100% sensor output divided by the total flow at 2% sensor output. Therefore, a perfectly linear bypass design would have a turndown of 50. Acceptable instruments can be made with tu ndowns les than the ideal 50, but the lower the turndown, the lower the accuracy potential of the instrument
• inlet screens also referred to as a "mesh"
• Figures IA and IB respectively depict the speed contour of a flow meter de vice without an inlet mesh and a flow meter device with an inlet mesh.
• the disclosed embodiments provide a dramatic improvement, over the current use of inlet screens by adding a turning vane.
• a turning vane 200 with a Sow mixer 206 installed upstream of an inlet screen is used to generate a more uniform flow so that the turndown value can reach the max value for a given bypass design and given mesh.
• Figure 3 illustrates the taming vane of Figure 2 in an assembly.
• This turning vane design can increase the turndown value by about 15% or more depending upon a given bypass design.
• the turning sane with a flow mixer more uniformly redistributes the fluid mass, so that more of the bypass mesh is used during maximum flow conditions, in the end, the turndown value reaches the ma value for a given bypass design and a given mesh.
• the turning vane 200 includes one or more vanes and a flow mi er 206.
• the vanes and flow mixer are made of metal.
• a vane consists of a flat section 202 upstream and a curved surface 204 downstream.
• the vanes form diffusers that distribute the flow across the available inlet area,
• the number, size, and shape of the vanes may vary within different embodiments.
• the angle of the curved surface 204 within a. plurality of vanes of a turning- vane will gradually increase from a bottom vane to a top vane as depicted in Figure 2.
• the flow mixer 206 is a piece of coarse metal mesh, which can be part of the turning vane 200 or separate element.
• the location of the turning vane 200 and the flow mixer 206 may be adjusted to reach the highest performance.
• the shape of the openings on the mixer can be an angular shape, such as star, circle, rectangle or a round shape such as a circle, oval, or ellipse.
• the dimensions can var for the specific purposes,
• figures 4-7 depict an example of a simulaied performance test of tbe turning vane 200 depicted in Fi gure 2.
• a uniform flow of nitrogen is specified at the inlet (e.g., 6 LPM, 60 LPM, 120 LPM, etc,) of the flow meter at 25T.
• the pressure drop is generated at the inlet and outlet of the sensor tube.
• the flow inside the sensor tube is not simulated because the flow through the sensor is at the order of magnitude of 0.005% of the total flow rate and has a negligible effect on the overall flow.
• the average pressure is measured at the locations of the inlet and outlet of the sensor tube. The verification has been conducted by comparing the numerical solutions with the experimental results so that the pressure drops in the simulations are in a good range of accuracy.
• Figures 4 A and 4S depict the difference in speed contour between a flo meter device that does not have the turning vane and mixer (Figure 4 A), and a flow meter device that includes the turning vane and mixer (Figure 4B).
• Figures 5 A. and SB depict the difference in pressure contour between a flow meter device that does not have the turning vane and mixer (Figure 5A), and a flow meter device that includes the turning vane and mixer ( Figure 5b).
• Tabic I presented below, is a chart that indicates the difference in flow rate at 2 seem and at 1 seem, and the difference in turndown for a flow meter device thai does not have the turning vane and mixer, and a flow meter device that includes the turning vane and mixer.
• Figure 6 is a graph depicting the differeace in turndown between the two devices represented in Table 1.
• FIG. 7 illustrates another embodiment of a turning vane 700 consisting of a single vane, in the depicted embodiment, the turnin vane 700 is employed upstream of an existing inlet screen mesh 710 that is located at the entrance of the bypass 720.
• the turning vane 700 may also include a flow mixer, as either an integrated or separate component, of the turning vane 700. Additionally, the angle, size (e.g., width and height), and number of vanes for the turning vane 700 may vary in different embodiments.
• FIG. 8 illustrates another example of a turning vane 800 with a flow mixer 810 in accordance with the disclosed embodiments.
• the turning vane 800 consists of three vanes 802, 804, and 806, in certain embodiments, the dimensions (e.g., length, width, height, thickness, etc.) of the three vanes 802, 804, and 806 may vary from one another or may vary between different designs.
• Each of the vanes may 802, 804, and 806 may comprise of one or more metal sections coupled together or alternatively, ma comprise of a single metal piece.
• the uppermost vase 802 may include a large flat section abutting the flow mixer (as compared to the embodiment depicted in Figure 2) that may further help distribute the flow across the available inlet area,
• Figures 9A-9E illustrate various configurations of a turning vane in an assembly in accordance with the disclosed embodiments.
• Figures A and 98 illustrate different support structures that may be employed with a turning vane in accordance with the disclosed embodiments.
• Figure 9A illustrates that in one embodiment, a portion of the curved section of a turning vane may be straightened to allow for partial flow through the turning va»e and provide additional support for the turning vane.
• Figure 9B employs a different design that uses a single vertical support leg tor providing additional support for the turning vane.
• Figure C depicts a similar embodiment to that of 98 except that the turning vane abuts the inlet screen in the assembly-
• Figure 9D depicts an embodime t in which a vertical support leg can be cut from a portion of the curved section similar to that of Figure 9A.
• Figure 9E illustrates a similar embodiment to that of f igure D, but without the flat portion of the vane abutting the inlet screen.
• each of the depicted embodiments may employ the use of a flow mixer as described above.
• FIGs iOA and JOB illustrate another embodiment of a turning vane 1000 in an assembly in accordance with the disclosed embodiments.
• the turning vane 1.00 includes a pair of support legs 101.0 for providing a support structure when installed in an assembly as shown in Figure 10B.
• the disclosed inventions provide various embodiments of a turning vane thai improves bypass linearit in a mass flow controller or mass flow meter, and thereby improving accuracy on process gas and the range of the instrument,

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Engineering & Computer Science (AREA)
• Automation & Control Theory (AREA)
• Chemical & Material Sciences (AREA)
• Dispersion Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Measuring Volume Flow (AREA)
• Flow Control (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=50190763

Family Applications (1)

Country Status (4)

Cited By (2)

Families Citing this family (3)

Citations (4)

Family Cites Families (25)

• 2014
  • 2014-02-09 EP EP14707533.7A patent/EP2972127B1/en active Active
  • 2014-02-09 JP JP2016500221A patent/JP2016510925A/ja active Pending
  • 2014-02-09 WO PCT/US2014/015461 patent/WO2014158375A1/en not_active Ceased
  • 2014-02-09 US US14/772,461 patent/US9399199B2/en active Active
• 2018
  • 2018-11-08 JP JP2018210633A patent/JP6777712B2/ja active Active

Patent Citations (4)

Also Published As

Similar Documents

Legal Events