Flow bypass ratio calculation of mass flow controller using gas factor

Abstract

A disclosed example flow sensor system includes a sensor tube and a bypass path that divide flow of a fluid through the system. A bypass ratio of the sensor is equal to a flow through the bypass divided by a flow through the sensor tube only. A heater element is used to heat a portion of the sensor tube. First and second sensors are arranged upstream and downstream of the heater element, respectively. A controller is connected to the heater element and to the first and second sensors, operable to receive signals from the first and second sensors corresponding to sensor flow of the fluid through the sensor tube, to calculate a sensor Reynolds number based on the sensor flow, and to calculate a total flow through the flow sensor system based on the sensor Reynolds number.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 797,456, filed April 30, 2025, entitled "FLOW BYPASS RATIO CALCULATION WITH GAS FACTORS FOR MASS FLOW CONTROLLERS". The entire contents of U.S. Provisional Patent Application Serial No. 63 / 797,456 are expressly incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to flow control, and more specifically, to the calculation of flow bypass ratios using gas factors with the aid of a mass flow sensor. Background Technology

[0004] A mass flow controller receives the flow rate of one or more gases, measures the amount of gas flowing, and controls the flow rate via a control valve. The controller can be used to respond to changes in fluid characteristics, including flow rate, volume, and fluid demand. Summary of the Invention

[0005] The disclosed example controller for a valve for a mass flow controller includes circuitry for determining and employing a flow bypass ratio calculated by one or more gas factors, substantially as illustrated and described in conjunction with at least one of the accompanying drawings, and more fully set forth in the claims. Attached Figure Description

[0006] These and other features, aspects, and advantages of this disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings, in which similar characters throughout the drawings denote similar parts, wherein:

[0007] Figure 1 This is a perspective view of an example valve for a mass flow controller according to various aspects of this disclosure.

[0008] Figure 2A and Figure 2B Example sensor tubes according to various aspects of this disclosure are illustrated.

[0009] Figure 3 This is an example method for receiving sensor data and determining total device flow rate according to various aspects of this disclosure.

[0010] The accompanying drawings are not necessarily drawn to scale. Where appropriate, similar or identical reference numerals are used to refer to similar or identical parts. Detailed Implementation

[0011] For the purpose of facilitating an understanding of the principles of the claimed technology and presenting its best operating mode as currently understood, reference will now be made to the embodiments shown in the accompanying drawings, and these embodiments will be described using specific language. However, it should be understood that this is not intended to limit the scope of the claimed technology, and such changes and further modifications in the illustrated apparatus, as well as such further applications of the principles of the claimed technology shown therein, are contemplated by those skilled in the art to which the claimed technology pertains.

[0012] Mass flow controllers are used in applications such as semiconductor manufacturing, biological processing, thin film processing, and chemical handling to deliver gases in precise ratios. In the example of semiconductor manufacturing, gases can be precisely delivered to different areas of a wafer. In addition to cost-effectiveness, such manufacturing applications benefit from faster response times, repeatability of results, and consistency of outcomes.

[0013] The mass flow controller may include a main pipe having an inlet and an outlet downstream of the inlet. Each includes one or more sensors, such as an inlet sensor and an outlet sensor for measuring flow pressure, flow rate, and / or temperature, respectively, as a list of non-limiting examples. A mass flow control valve may be included to control the delivery of fluid flow.

[0014] A controller (e.g., control circuitry, processor, computer, etc.) may be combined with and / or connected to a mass flow sensor and / or valve. The controller can be programmed to control the delivery of a desired flow rate through the outlet. For example, the controller may compare the actual (measured) flow rate at the mass flow sensor at the outlet. If the difference between the actual measured flow rate and the desired flow rate exceeds a threshold amount, the controller is programmed to adjust the fluid flow through the valve until the actual flow rate is within a predetermined range of the desired flow rate. This type of precise valve control provides improved delivery of such fluids.

[0015] The disclosed example controller is configured to calculate the flow rate through a mass flow measurement device by calculating the flow rate through a sensor tube and / or a bypass path. The calculation may include calculating the bypass flow rate by calculating the sensor Reynolds number and running that sensor Reynolds number through a flow bypass ratio polynomial, which can be determined in various ways, such as experimentally.

[0016] As disclosed herein, the calculated sensor Reynolds number is used to calculate the flow bypass ratio, which can then be used to calculate the total unit flow rate. This is particularly effective because the bypass error is a function of the Reynolds number. In some examples, the sensor comprises a sensor tube that divides the fluid flow and a bypass path, such that the bypass ratio is equal to the flow rate through the bypass divided by the flow rate through the sensor tube alone.

[0017] One or more coil elements are arranged between the upstream and downstream portions of the sensor tube. In one embodiment, the central coil (e.g., Figure 2A The coil 34) is used as a heater to add power to the system, while the upstream and downstream coils (e.g., respectively) Figure 2A Coils 32 and 36 are used as resistance temperature sensors. As fluid flows through the pipe, a temperature gradient is created as heat is transferred through the fluid from the upstream portion of the pipe to the downstream portion. The coils are suitably configured such that the temperature gradient at the desired flow rate causes a change in resistance across the coils, which is represented as a voltage. The voltage difference between these coils then becomes a representation of the temperature gradient, which itself is a representation of the flow rate through the sensor. In one embodiment, the voltage reference is calibrated corresponding to a predetermined flow rate for one or more gas types and compensated for according to applicable fluid characteristics to account for differences in heat transfer between fluids. The steady-state rate of heat transfer from the heater to the fluid will be determined by the following defined formula:

[0018]

[0019] Where Q is the heat transfer rate of the fluid flowing through the pipe, m is the flow rate, Cp is the specific heat, and T is the temperature change corresponding to the voltage difference.

[0020] In fluid dynamics, the Reynolds number (Re) is used to determine the mode of fluid flow. For example, fluid flow characteristics can oscillate between laminar (e.g., smooth, uniform flow) and turbulent (e.g., unstable, non-uniform flow).

[0021] The Reynolds number is a dimensionless quantity that can be used to predict fluid flow patterns by comparing the inertial forces of the fluid with the viscous forces on the fluid. Analysis shows that low Reynolds numbers correspond to essentially laminar flow, while high Reynolds numbers correspond to more turbulent flow. Specifically, the Reynolds number of a fluid is the ratio of inertial forces to viscous forces. Therefore, the resulting quantity is dimensionless. The general formula for the Reynolds number is given in the following Equation 1:

[0022]

[0023] Where ρ is the fluid density, v is the fluid velocity, L is the characteristic length of the flow cross section, and μ is the dynamic viscosity of the given fluid.

[0024] The apparatus and method disclosed herein are designed to regulate the valves of a mass flow controller, providing improved stability and accuracy, as well as improved response time to varying flow rates, compared to conventional mass flow controllers. One advantage of the disclosed design is improved accuracy when using previously uncalibrated gases. Therefore, the compensation factor allows for the use of a wide variety of gases without requiring specific calibration techniques.

[0025] Some examples of precision gas distribution systems employing mass flow control valves also include a temperature sensor configured to measure the temperature of the input process gas flow. For instance, control circuitry may be configured to control the valve to regulate the gas flow based on the measured temperature.

[0026] Now turn to the attached image. Figure 1 This is a view of an example mass flow and / or density measurement device 10 according to various aspects of this disclosure, in which a solenoid valve mass flow controller is employed. The illustrated mass flow measurement and control system 10 includes a process setup 12, a controller or computing unit 14 (e.g., control circuitry), and one or more sensors 16. The device 10 is connected to a flow base 20 to direct gas / fluid from an inlet 18 to an outlet 26. A flow control valve 22 is arranged between the inlet and outlet, and the flow valve is controlled by current flowing through a solenoid 24 based on commands from the control unit 14.

[0027] like Figure 1 As shown, the gas / fluid at the inlet can be divided between sensor tube 28 and bypass path 29. For example, sensor tube 28 diverts a portion of the fluid to mass flow sensor 16, while the remaining fluid is directed through bypass path 29. Downstream of flow base 20, sensor tube 28 and bypass path converge before flow control valve 22. Typically, sensor tube 28 is smaller than bypass path tubing. As disclosed herein, sensor 16 is configured to measure fluid characteristics before and after the heating element, and its measurements are transmitted to controller 14. Based on the measurements, controller 14 controls solenoid 24 to activate plunger, thereby regulating the fluid flow through flow control valve 22.

[0028] Figure 2A A detailed view of sensor 16 is provided, which includes a sensor tube 28 having an upstream portion for receiving fluid 30A and a downstream portion for discharging fluid 30B. Connected to or otherwise in contact with sensor tube 28 are an upstream sensor (coil) 32, a downstream sensor (coil) 36, and a heater element or coil 34 disposed between the two sensors.

[0029] In some examples, heater coil 34 applies a constant heat flux to sensor tube 28. The upstream and downstream coils generate a voltage proportional to the change in coil resistance due to temperature. As fluid flows through tube 28, internal convection creates a temperature gradient between upstream sensor 32 and downstream sensor 36, which is proportional to the mass flow rate through sensor tube 28. This temperature gradient creates a voltage difference between upstream sensor 32 and downstream sensor 36, serving as the raw signal for the thermal mass flow meter.

[0030] exist Figure 2BIn the example shown, upstream coil sensing element 282 and downstream sensing element 284 are thermally coupled to a flow path provided by flow sensor conduit 268. In this example, each coil 35, 37 can be used as a heating element, as a sensor, or both. For example, current can be supplied to each coil to generate heat, and / or current can be used to measure the voltage difference between the coils. As disclosed herein, this difference represents a temperature gradient between the coils, which is represented by the flow rate of the sensor.

[0031] In some examples, the controller is connected to a first coil and a second coil and is configured to apply power to one or both of the first coil and the second coil to generate heat (e.g., resistance heating, as a heating element). The controller may receive signals from the other of the first coil and the second coil, which correspond to the sensor flow rate of the fluid passing through the sensor tube. With these signals, the controller may calculate the sensor Reynolds number based on the sensor flow rate, and calculate the total flow rate through the flow sensor system based on the sensor Reynolds number.

[0032] In some examples, the controller applies power to and receives signals from either the first or second coil in an alternating pattern, which can be simultaneous (e.g., heating the first coil while sensing from the second coil). In other examples, each coil can be heated / generated in a predetermined pattern, which can be shared between coils or different for each coil.

[0033] Figure 3 An example process 40 is shown for calculating the total device flow rate of a mass flow controller using Reynolds number calculation. Process 40 can be any method or algorithm for calculating the total device flow rate, including via a controller, control circuitry, and / or computing device (e.g., controller 14).

[0034] Therefore, the example procedure provides compensation for Reynolds number losses for different gases. The Reynolds number is useful because bypass error is a function of the Reynolds number, and the bypass ratio error can be corrected using the Reynolds number of the sensor tube, as discussed regarding... Figure 3 The explanation given.

[0035] As shown in box 42, the gas / fluid is directed through the mass flow controller. For example, the gas / fluid may be supplied at inlet 18.

[0036] In frame 44, a portion of the gas / fluid is diverted through sensor tube 28 and enters sensor device 16.

[0037] In box 46, the flow rate through the sensor is calculated. For example, as an initial step, the raw sensor signal is used to obtain the zero-flow-temperature compensation (ZTC) value applied at the current zero value. This is done using equations 1A and 1B below:

[0038]

[0039] in

[0040]

[0041] Then, using ΔV calculated from Equation 1A Zeroed The sensor signal operates via a dedicated sensor flow polynomial (which can be determined experimentally). The flow rate through the sensor can be calculated via Equation 2 below. This is achieved by using ΔV for a given type of gas. Zeroed Q is adjusted for the specific type of gas being guided through the sensor. sensor Equation 2:

[0042]

[0043] Q sensor It is the fluid flow rate measured by the sensor, C n C n-1 ...C1 and B o These are polynomial coefficients obtained through experiments or numerical simulations, used to map sensor voltage to sensor flow rate, and SF is a gas conversion factor, which is a function of the fluid properties of the calibration gas and process gas (e.g., the specific heat of the gas derived from heat transfer). In some embodiments, this conversion factor can be of the following form: It can be a fixed value for each fluid, or it can combine temperature and / or pressure dependencies.

[0044] Although Q is provided sensor Some examples are determined by polynomial equations, but in some examples, refer to lists such as linearization tables that map voltage to flow.

[0045] In box 48, the sensor Reynolds number is then calculated using the sensor flow rate through the sensor fluid flow rate in Equation 2, using Equation 3 below.

[0046]

[0047] Where Re is the Reynolds number of the sensor flow rate, and Q... sensor The sensor flow rate is calculated according to Equation 2, and X Re This is a scaling factor that takes into account fluid properties, such as the density and viscosity of a particular gas, in the dimensionless value of Re. The scaling factor can be used as a static factor, derived as a ratio of the density and viscosity of a single gas, or as a ratio of the process gas to the calibration gas. Alternatively or additionally, the Re factor can be used as a function of pressure and / or temperature, which may be advantageous for a given scenario.

[0048] In box 50, Q Bypass It can be calculated as Q FlowCalStandard Subtract Q sensor The value of is provided in Equation 4 below.

[0049]

[0050] It can be rewritten as solving Q Bypass As shown below:

[0051]

[0052] In box 52, the sensor Reynolds number Re from Equation 3 is then run through the flow bypass ratio (FBR) polynomial from Equation 4 (which can be determined experimentally). FBR is the flow rate (Q) of the bypass path. Bypass ) and the flow rate (Q) of the sensor tube sensor The ratio of ).

[0053] The flow bypass ratio (FBR) polynomial is provided in Equation 5 below:

[0054]

[0055] Where FBR is the flow bypass ratio, and C Re,n ...and C Re,1 and B Re is the polynomial coefficient of the bypass ratio curve relative to the Reynolds number obtained experimentally or through numerical simulation for each gas, and Re is the sensor Reynolds number calculated using the sensor flow rate and Reynolds number scaling factor mentioned above.

[0056] Once FBR is calculated, Q can be calculated using Equation 4. Bypass .

[0057] In box 54, the flow of gas / fluid is directed through the bypass path.

[0058] As shown in box 56, with both the flow through the sensor and the bypass already calculated, the total device flow is calculated using Equation 6 below.

[0059]

[0060] In box 58, the controller commands changes to one or more components of the mass flow device based on a calculated value of the total device flow rate. For example, the controller may command the activation or deactivation of a solenoid to change the valve positioning, thereby controlling the flow rate of fluid through the flow body.

[0061] In some implementations, example controller / control circuitry 14 may be an integrated processing system, a programmable logic controller, a general-purpose computer, a laptop computer, a tablet computer, and / or any other type of processing system configured to communicate with sensors and / or valves. For example, the control circuitry system may include a processor, memory, and storage devices. An example processor may be any general-purpose central processing unit (CPU) from any manufacturer. In some other examples, the processor may include one or more dedicated processing units, such as a RISC processor with an ARM core, a graphics processing unit, a digital signal processor, and / or a system-on-a-chip (SoC). The processor executes machine-readable instructions, which may be stored locally at the processor (e.g., in a included cache or SoC), in memory (e.g., random access memory or other volatile memory, read-only memory, or other non-volatile memory such as flash memory), and / or in storage devices. Example storage devices may be hard disk drives, solid-state drives, hybrid drives, RAID arrays, and / or any other high-capacity data storage devices.

[0062] In a disclosed example, a flow sensor system includes: a sensor tube and a bypass path that divide the flow rate of fluid through the system, wherein the bypass ratio of the sensor is equal to the bypass flow rate divided by the flow rate through the sensor tube; a heater element for heating a portion of the sensor tube; a first sensor and a second sensor, the first sensor being disposed upstream of the heater element and the second sensor being disposed downstream of the heater element; and a controller connected to the heater element and the first and second sensors. In the example, the controller is operable to: receive signals from the first and second sensors corresponding to the sensor flow rate of the fluid through the sensor tube; calculate a sensor Reynolds number based on the sensor flow rate; and calculate the total flow rate through the flow sensor system based on the sensor Reynolds number.

[0063] In some examples, the controller is also configured to measure the flow rate through the first and second sensors based on the measured voltage across the first and second sensors.

[0064] In some examples, the controller is also configured to calculate the sensor Reynolds number based on the value of the sensor fluid flow rate using the following equation:

[0065]

[0066] Where Re is the Reynolds number of the sensor, Qsensor is the value of the fluid flow rate of the sensor, and X ReIt is a scaling factor derived from fluid density ρfluid and fluid viscosity μfluid.

[0067] In some examples, X Re It is calculated as a function of pressure, temperature, or both.

[0068] In some examples, the controller is also configured to calculate the sensor Reynolds number based on the value of the sensor fluid flow rate using the following equation:

[0069]

[0070] Where Re is the sensor Reynolds number, and Q... sensor X is the value of the fluid flow rate of the sensor, and X Re It is a scaling factor derived from the fluid density and viscosity of the measured gas relative to the process gas.

[0071] In some examples, X Re Used as a function of pressure, temperature, or both.

[0072] In some examples, the controller is also configured to calculate the flow bypass ratio (FBR) using a polynomial based on the sensor Reynolds number, wherein the polynomial is provided in the following equation:

[0073]

[0074] Where FBR is the flow bypass ratio, C Re,n ...and C Re,1 and B Re is the polynomial coefficient of the bypass ratio curve with respect to the Reynolds number, and Re is the Reynolds number of the sensor.

[0075] In some examples, the FBR is the flow (Q) of the bypass path. Bypass ) and the flow rate (Q) of the sensor tube sensor The ratio of ).

[0076] In some examples, the total flow includes the sensor flow and the bypass flow.

[0077] In some examples, the heater element is one or more coils configured to heat the sensor tube, and the heater element can be controlled by the controller.

[0078] In some examples, the first sensor and the second sensor are one or more coils configured to generate current during the flow of the fluid, and the first sensor and the second sensor are connected to the controller.

[0079] In some publicly available examples, a flow sensor system includes: a sensor tube and a bypass path that divide the flow rate of fluid through the system; a first coil for heating or sensing along a first portion of the sensor tube; a second coil for heating or sensing along a second portion of the sensor tube; and a controller connected to the first and second coils. In the examples, the controller is configured to: apply power to the first and second coils to generate heat; receive signals from the first and second sensors corresponding to the sensor flow rate of the fluid through the sensor tube; calculate a sensor Reynolds number based on the sensor flow rate; and calculate the total flow rate through the flow sensor system based on the sensor Reynolds number.

[0080] In some examples, the controller is configured to apply the power in an alternating mode and receive the signal from either the first coil or the second coil.

[0081] In some examples, the controller is configured to apply power to the first coil while receiving a signal from the second coil.

[0082] In some examples, the controller is also configured to calculate the sensor Reynolds number based on the value of the sensor fluid flow rate using the following equation:

[0083]

[0084] Where Re is the Reynolds number of the sensor, and Q sensor X is the value of the fluid flow rate of the sensor, and X Re It is a scaling factor derived from fluid density ρfluid and fluid viscosity μfluid.

[0085] In some examples, X Re It is calculated as a function of pressure, temperature, or both.

[0086] In some examples, the controller is also configured to calculate the sensor Reynolds number based on the value of the sensor fluid flow rate using the following equation:

[0087]

[0088] Where Re is the Reynolds number of the sensor, Qsensor is the value of the fluid flow rate of the sensor, and X Re It is a scaling factor derived from the fluid density and viscosity of the measured gas relative to the process gas.

[0089] In some examples, X Re Used as a function of pressure, temperature, or both.

[0090] In some examples, the controller is also configured to calculate the flow bypass ratio (FBR) using a polynomial based on the sensor Reynolds number, wherein the polynomial is provided in the following equation:

[0091]

[0092] Where FBR is the flow bypass ratio, C Re,n ...and C Re,1 and B Re is the polynomial coefficient of the bypass ratio curve with respect to the Reynolds number, and Re is the Reynolds number of the sensor.

[0093] In some examples, the FBR is the flow (Q) of the bypass path. Bypass ) and the flow rate (Q) of the sensor tube sensor The ratio of ).

[0094] As used herein, “and / or” means any one or more items in a list connected by “and / or”. As an example, “x and / or y” means any element in the three-element set {(x), (y), (x, y)}. In other words, “x and / or y” means “one or both of x and y”. As another example, “x, y and / or z” means any element in the seven-element set {(x), (y), (z), (x, y), (x, z), (y, z), (x, y, z)}. In other words, “x, y and / or z” means “one or more of x, y and z”. As used herein, the term “exemplary” means used as a non-limiting example, instance, or illustration. As used herein, the terms “such as” and “for example” introduce a list of one or more non-limiting examples, instances, or illustrations.

[0095] While this method and / or system has been described with reference to certain specific embodiments, those skilled in the art will understand that various changes can be made and equivalents can be substituted without departing from the scope of this method and / or system. For example, blocks and / or components of the disclosed examples may be combined, divided, rearranged, and / or otherwise modified. Furthermore, many modifications may be made to adapt particular situations or materials to the teachings of this disclosure without departing from the scope of this disclosure. Therefore, this method and / or system is not limited to the specific embodiments disclosed. Rather, this method and / or system will include all embodiments that fall within the scope of the appended claims, both literally and under the principle of equivalents.

Claims

1. A flow sensor system, comprising: A sensor tube and a bypass path, wherein the sensor tube and the bypass path divide the flow rate of fluid through the system, wherein the bypass ratio of the sensor is equal to the bypass flow rate divided by the flow rate through the sensor tube; A heater element for heating a portion of the sensor tube; A first sensor and a second sensor, wherein the first sensor is arranged upstream of the heater element and the second sensor is arranged downstream of the heater element; A controller, connected to the heater element and the first and second sensors, wherein the controller is configured to: - Receive signals from the first sensor and the second sensor corresponding to the sensor flow rate of the fluid passing through the sensor tube; - Calculate the sensor Reynolds number based on sensor flow rate; as well as - Calculate the total flow rate through the flow sensor system based on the Reynolds number of the sensor.

2. The flow sensor system of claim 1, wherein the controller is further configured to measure the flow rate through the first sensor and the second sensor based on the measured voltage across the first sensor and the second sensor.

3. The flow sensor system of claim 1, wherein the controller is further configured to calculate the sensor Reynolds number based on the value of the fluid flow rate of the sensor using the following equation: ， Where Re is the Reynolds number of the sensor, and Q sensor X is the value of the fluid flow rate of the sensor, and X Re From fluid density ρ fluid and fluid viscosity μ fluid Exported scaling factor.

4. The flow sensor system of claim 3, wherein X Re It is calculated as a function of pressure, temperature, or both.

5. The flow sensor system of claim 1, wherein the controller is further configured to calculate the sensor Reynolds number based on the value of the fluid flow rate of the sensor using the following equation: ， Where Re is the Reynolds number of the sensor, and Q sensor X is the value of the fluid flow rate of the sensor, and X Re It is a scaling factor derived from the fluid density and viscosity of the measured gas relative to the process gas.

6. The flow sensor system of claim 5, wherein X Re Used as a function of pressure, temperature, or both.

7. The flow sensor system of claim 3, wherein the controller is further configured to calculate the flow bypass ratio (FBR) using a polynomial based on the sensor Reynolds number, wherein the polynomial is provided in the following equation: ， Where FBR is the flow bypass ratio, C Re,n ...and C Re,1 and B Re is the polynomial coefficient of the bypass ratio curve with respect to the Reynolds number, and Re is the Reynolds number of the sensor.

8. The flow sensor system of claim 7, wherein the FBR is the flow rate (Q) of the bypass path. Bypass ) and the flow rate (Q) of the sensor tube sensor The ratio of ).

9. The flow sensor system of claim 1, wherein the total flow includes the sensor flow and the bypass flow.

10. The flow sensor system of claim 1, wherein the heater element is one or more coils configured to heat the sensor tube, and the heater element is controllable by the controller.

11. The flow sensor system of claim 1, wherein the first sensor and the second sensor are one or more coils configured to generate current during the flow of the fluid, and the first sensor and the second sensor are connected to the controller.

12. A flow sensor system, comprising: A sensor tube and a bypass path, wherein the sensor tube and the bypass path divide the flow rate of the fluid through the system; A first coil, the first coil being used for heating or sensing along a first portion of the sensor tube; A second coil, which is used for heating or sensing along a second portion of the sensor tube; A controller, connected to the first coil and the second coil, wherein the controller is configured to: - Power is applied to the first coil and the second coil to generate heat; - Receive signals from the first sensor and the second sensor corresponding to the sensor flow rate of the fluid passing through the sensor tube; - Calculate the sensor Reynolds number based on sensor flow rate; as well as - Calculate the total flow rate through the flow sensor system based on the Reynolds number of the sensor.

13. The flow sensor system of claim 12, wherein the controller is configured to apply the power in an alternating mode and receive the signal from the first coil or the second coil.

14. The flow sensor system of claim 12, wherein the controller is configured to apply power to the first coil while receiving a signal from the second coil.

15. The flow sensor system of claim 12, wherein the controller is further configured to calculate the sensor Reynolds number based on the value of the fluid flow rate of the sensor using the following equation: ， Where Re is the Reynolds number of the sensor, and Q sensor X is the value of the fluid flow rate of the sensor, and X Re From fluid density ρ fluid and fluid viscosity μ fluid Exported scaling factor.

16. The flow sensor system of claim 14, wherein X Re It is calculated as a function of pressure, temperature, or both.

17. The flow sensor system of claim 12, wherein the controller is further configured to calculate the sensor Reynolds number based on the value of the fluid flow rate of the sensor using the following equation: ， Where Re is the Reynolds number of the sensor, and Q sensor X is the value of the fluid flow rate of the sensor, and X Re It is a scaling factor derived from the fluid density and viscosity of the measured gas relative to the process gas.

18. The flow sensor system of claim 16, wherein X Re Used as a function of pressure, temperature, or both.

19. The flow sensor system of claim 14, wherein the controller is further configured to calculate the flow bypass ratio (FBR) using a polynomial based on the sensor Reynolds number, wherein the polynomial is provided in the following equation: ， Where FBR is the flow bypass ratio, C Re,n ...and C Re,1 and B Re is the polynomial coefficient of the bypass ratio curve with respect to the Reynolds number, and Re is the Reynolds number of the sensor.

20. The flow sensor system of claim 18, wherein the FBR is the flow rate (Q) of the bypass path. Bypass ) and the flow rate (Q) of the sensor tube sensor The ratio of ).

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