KR20190002985A - Mass flow control apparatus using capacitance measuring and mass flow control method using the same - Google Patents

Abstract

According to one embodiment of the present invention, a mass flow controlling apparatus using capacitance measurement may comprise: a first capacitor positioned on a moving path of a fluid; a second capacitor spaced apart from the first capacitor and positioned on the moving path of the fluid; a measurement circuit connected to the first and second capacitors and measuring the first and second capacitances of the fluid through the first and second capacitors; and a control unit measuring and controlling the flow rate of the fluid moved on the moving paths of the fluid based on capacitance values measured from the measurement circuit. The mass flow controlling apparatus may accurately measure the flow rate of the fluid flowing using the capacitors.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mass flow rate control apparatus using capacitance measurement and a mass flow rate control method using the same,

The present invention relates to a mass flow controller using capacitance measurement and a mass flow control method using the same.

The measurement of gas and gas at mass flow rate has been applied effectively in various industrial fields. Typical flowmeters for measuring gases or gases include orifices, differential pressure flow meters, vortex flow meters, turbine flow meters, ultrasonic flow meters, area flow meters and thermal mass flow meters.

Among these flowmeters, the remainder except the thermal mass flowmeter is a flowmeter that measures only the volume of the fluid. When the temperature or pressure of a process requiring fluid measurement is different from the design, it can not be corrected properly. That is, It is a flow meter that measures only quantity.

A thermal mass flowmeter is also known as a classifying flowmeter. A thermal mass flow meter places a heated object in a flowing fluid and the heated object cools as heat exchanges between the fluid and the heated object. Since this cooling rate is a function of the flow velocity, the flow velocity can be determined by measuring the temperature of the heated object. In addition, since the energy required to raise the fluid to a constant temperature is a function of the flow rate, the flow rate can be obtained by measuring the energy required to raise the temperature of the flowing fluid to a certain temperature.

1 is a view showing the principle of measuring a flow rate.

Referring to FIG. 1, a measuring tube 120, which is a long U-shaped capillary (also referred to as bypass), is formed in a main pipe 110, which is a pipe through which a fluid passes. The measuring tube 120 is provided with first and second resistance heating elements 122 and 124 at predetermined intervals. When the fluid does not flow, the first and second resistance heating elements 122 and 124 of the measuring tube 120 are thermally balanced to have the same temperature. However, when the fluid flows, the heat is moved by the flow of the fluid. Therefore, the thermal equilibrium state is broken and a temperature difference occurs between the first and second resistance heating bodies 122 and 124. [ The generated temperature difference is detected through the measurement circuit 126 and the control unit 130. The flow rate of the fluid flowing in the main pipe 110 can be inferred and measured based on the temperature difference in the measuring pipe 120.

However, since the flow rate is measured using the temperature difference, it may be influenced by the external environment (for example, the temperature of the place where the main pipe is installed). In addition, the measured value through the measuring circuit 126 is corrected using an algorithm, and then is transmitted to the controller 130. The controller 130 measures the flow rate of the fluid based on the corrected value. The controller 130 controls the flow rate of the fluid passing through the main pipe 110 by driving the motor 162 connected to the valve 164 based on the measured flow rate. If the correction values are accumulated in the repeated flow measurement process, there will be a deviation between the actual fluid flow rate and the corrected value. Such deviations can make it difficult to measure the exact flow rate of the fluid. Accurate flow control is also required for precise flow control.

Modern industries have become increasingly sophisticated and diversified, and in addition to measuring fluids and especially gas flows, increasingly diverse processes require highly accurate fluid measurements. An expensive flow measurement device is required for high-precision measurement.

An object of the present invention is to provide a mass flow rate control apparatus using a capacitance measurement method capable of measuring a flow rate of a fluid by measuring a capacitance value of the fluid using a capacitor, .

According to an aspect of the present invention, there is provided a mass flow controller using capacitance measurement. The apparatus includes a first capacitor located on a fluid path, a second capacitor disposed between the first capacitor and the first capacitor, A measurement circuit coupled to the first and second capacitors and configured to measure the first and second capacitances of the fluid through the first and second capacitors, And a controller for measuring and controlling the flow rate of the fluid moving on the movement path of the fluid based on the measured capacitance value.

In an embodiment, each of the first capacitor and the second capacitor may comprise a pair of first and second plates and a pair of third and fourth plates facing each other.

In an embodiment, at least one of the first capacitor or the second capacitor may be located inside the fluid flow pipe including the fluid flow path.

In an embodiment, at least one pair of the first and second plates and the pair of third and fourth plates may be positioned in the same direction as the direction of movement of the fluid, As shown in Fig.

In an embodiment, the plates provided in at least one pair of the pair of first and second plates and the pair of third and fourth plates may be spaced at regular intervals or at regular intervals Can be spaced apart.

In an embodiment, the measuring circuit may comprise a bridge circuit.

In an embodiment, the apparatus may further include a flow distributor provided in at least one of the first and second plates and between the third and fourth plates, for distributing the flow of the fluid.

In an embodiment, the flow distributing unit may include a distillation column.

In an embodiment, the control unit may further include a control valve for controlling the flow rate of the fluid moving on the fluid movement path, the opening and closing being controlled according to the control unit.

The flow rate control method using the mass flow rate control apparatus using the capacitance measurement according to the embodiment of the present invention is characterized in that the fluid is moved into the fluid flow passage and the mass flow rate control apparatus according to any one of claims 1 to 9 Measuring a first capacitance value of the fluid using a first capacitor and a second capacitance of the fluid using the second capacitor of the mass flow controller according to any one of claims 1 to 9, Measuring the first and second capacitances, transferring the first and second capacitance values measured by the first and second capacitors to the controller, and based on the measured first and second capacitance values, Measuring the flow rate of the fluid, and controlling the flow rate of the fluid in the control section.

In one embodiment of the present invention, the control unit may sequentially measure the first and second capacitance values using the first and second capacitors, or may simultaneously measure the first and second capacitance values using the first and second capacitors, 2 Capacitance value can be measured.

The effect of the mass flow control apparatus using the capacitance measurement according to the present invention and the mass flow control method using the same will be described below.

According to at least one of the embodiments of the present invention, the flow rate of the fluid flowing through the capacitor can be accurately measured. Based on this, accurate flow control is possible.

In addition, according to at least one embodiment of the present invention, the capacitor can be installed inside the tube through which the fluid flows, and it is not necessary to separately provide a measuring tube for measuring the flow rate.

1 is a view showing the principle of measuring a flow rate.
2 is a view showing a concept of a mass flow control device according to a preferred embodiment of the present invention.
3 is a view showing a mass flow controller according to a preferred embodiment of the present invention.
4 is a view showing first and second capacitors of a mass flow controller according to a preferred embodiment of the present invention.
5 is a view showing a measuring circuit of the mass flow controller according to the preferred embodiment of the present invention.
6 is a block diagram of a mass flow controller according to another embodiment of the present invention.
7 is a view showing a mass flow control device according to still another preferred embodiment of the present invention.
8 is a view showing a mass flow control device according to still another preferred embodiment of the present invention.
Fig. 9 is a view showing a cross section of the mass flow control device of Fig. 8. Fig.
10 is a flowchart illustrating a method of controlling a flow rate of a fluid using a mass flow controller according to a preferred embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals are used to designate identical or similar elements, and redundant description thereof will be omitted. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role. In the following description of the embodiments of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the embodiments disclosed herein may be blurred. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. , ≪ / RTI > equivalents, and alternatives.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms. The terms are used only for the purpose of distinguishing one component from another.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The singular expressions include plural expressions unless the context clearly dictates otherwise.

In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

2 is a view showing a concept of a mass flow control device according to a preferred embodiment of the present invention.

Referring to FIG. 2, the mass flow controller 200 of the present invention may include a first capacitor 220, a second capacitor 230, a measuring circuit 250, and a controller 260. The first and second capacitors 220 and 230 may be positioned on a movement path through which the fluid is moved. In the embodiment of the present invention, the first and second capacitors 220 and 230 may be provided inside the fluid flow pipe 210. The fluid transfer tube 210 may have a hollow space in which a fluid moves in a tubular shape. The fluid can be moved to the inner space of the fluid transfer tube 210 while flowing. The fluid moving tube 210 may be a separate tube having the first and second capacitors 220 and 230 therein. In this case, the fluid transfer tube 210 can be inserted in the middle of a general conduit (main tube) through which fluid is transferred. Alternatively, the first and second capacitors 220 and 230 may be inserted into a general conduit (main pipe) through which fluid is transferred. The fluid transfer tube 210 may be, for example, a quartz tube.

In the present invention, the case where the first and second capacitors 220 and 230 are provided inside the fluid moving tube 210 as a general conduit will be described. The fluid moving along the fluid moving tube 210 can be moved while sequentially passing through the first capacitor 220 and the second capacitor 230. The first and second capacitors 220 and 230 are configured to measure the capacitance value of the fluid.

In the present invention, two capacitors 220 and 230 are used, and the description is based on this. However, the number of capacitors is not limited, and three or more capacitors can be used.

The measurement circuit 250 is electrically connected to the first and second capacitors 220 and 230 and may measure the capacitance value of the fluid passing through the first and second capacitors 220 and 230. The capacitance value of the measured fluid correlates with the dielectric constant of the fluid passing through the fluid moving tube 210, the moving velocity of the fluid, the cross-sectional area of the fluid moving tube 210, and the density of the fluid (hereinafter referred to as a parameter for measuring the flow rate) . Therefore, the flow rate of the moving fluid can be measured using the capacitance value of the fluid.

The first and second capacitors 220 and 230 may be sequentially driven to measure the electrostatic capacitance value of the fluid. In another embodiment, the first and second capacitors 220 and 230 may be simultaneously driven to measure the capacitance value of the fluid.

The controller 260 receives the capacitance values measured by the first and second capacitors 220 and 230 from the measurement circuit 250 and can perform an algorithm for measuring the flow rate of the fluid based on the capacitance values. The control unit 260 may include a flow rate measuring unit 262 and a control signal generating unit 264. The flow measuring unit 262 can measure the flow rate of the fluid using the capacitance values measured by the first and second capacitors 220 and 230 through the measuring circuit 250. The flow measuring unit 260 may store data on the flow rate of the fluid according to the electrostatic capacitance value by an algorithm. The flow rate measuring unit 262 may be connected to the control signal generating unit 264. The control signal generator 264 generates a control signal and controls the motor 272 using the control signal to control the degree of opening and closing of the control valve 274 provided in the fluid moving tube 210. [ It is determined whether or not control of the control valve 274 is necessary according to the flow rate of the fluid measured by the flow rate measuring unit 262. If it is determined that the control of the control valve 272 is necessary, The degree of opening and closing of the control valve 274 can be controlled to control the flow rate of the fluid.

The mass flow controller 200 may further include a display unit (not shown). The display unit may display the capacitance of the fluid measured by the first and second capacitors 220 and 230 and the flow rate of the fluid measured by the controller 260 using the measuring circuit 250. The display unit is located outside the fluid transfer tube 210 so that the user can confirm the flow rate of the fluid moving inside the fluid transfer tube 210.

3 is a view showing a mass flow controller according to a preferred embodiment of the present invention.

Referring to FIG. 3, the first capacitor 320 may be formed of a pair of first and second plates 322 and 324. The first and second plates 322 and 324 can be made into a plate-like conductor. The first and second plates 322 and 324 may be spaced apart from each other with a predetermined gap therebetween and may be provided inside the fluid transfer pipe 310. Fluid can pass through the spaces between the facing first and second plates 322 and 324 so that the first and second plates 322 and 324 can function as the first capacitor 320. Although the first and second plates 322 and 324 are shown in the form of a rectangular plate, it is possible to perform various deformations to measure the electrostatic capacitance of the fluid.

A portion of the fluid passing through the fluid transfer tube 310 may be moved through the space between the first and second plates 322 and 324. When the fluid is moving, the measurement circuit 250 can be used to measure the capacitance value of the fluid passing through the first and second plates 322, 324.

For example, the first and second plates 322 and 324 may be provided to face in the same direction as the direction of movement of the fluid. The second plate 324 may be positioned at an upper portion in the inner space of the fluid transfer tube 310 and the second plate 324 may be positioned at a lower portion of the inner space of the fluid transfer tube 310 to face the first plate 322. [ The first and second plates 322 and 324 may be connected to the measurement circuit 250.

The second capacitor 330 may be constituted by the third and fourth plates 332 and 334 in the same manner as the first capacitor 320. The third and fourth plates 332 and 334 may be formed into a plate-like conductor. The third and fourth plates 332 and 334 may be spaced apart from each other with a predetermined gap therebetween, and may be provided inside the fluid transfer pipe 310. The fluid can pass through the spaces between the facing third and fourth plates 332 and 334 and the third and fourth plates 332 and 334 can function as the second capacitor 330. Although the third and fourth plates 332 and 334 are shown in the form of a rectangular plate, it is possible to perform various deformations to measure the electrostatic capacitance of the fluid.

A portion of the fluid passing through the inside of the fluid transfer pipe 310 can be moved through the space between the third and fourth plates 332 and 334. When the fluid is moving, the measurement circuit 250 can be used to measure the capacitance value of the fluid passing through the third and fourth plates 332, 334.

For example, the third and fourth plates 332 and 334 may be provided so as to face each other in a direction different from the moving direction of the fluid (for example, a direction perpendicular to the moving direction of the fluid). The third plate 332 may be positioned in the inner space of the fluid transfer tube 310 and the fourth plate 334 may be positioned rearward in the fluid transfer tube inner space to face the third plate 332. The third and fourth plates 332 and 334 may be connected to the measuring circuit 250.

Fluid moving inside the fluid transfer tube 310 can be moved through the first capacitor 320 and the second capacitor 330. At this time, the measurement circuit 250 can measure the first and second capacitance values of the fluid passing through the first and second capacitors 320 and 330. Here, since the fluid passes through the first and second capacitors 320 and 330 while moving, the first and second capacitance values measured by the first and second capacitors 320 and 330 continuously change. Therefore, the flow rate measuring unit 260 can measure the flow rate by using the rate of change of the measured capacitance value as a parameter for measuring the flow rate.

A flow distribution unit 340 may be further disposed between the first capacitor 320 and the second capacitor 330 to distribute the fluid evenly inside the fluid flow pipe 310. The flow distributor 340 can perform a function of distributing the fluid evenly in order to prevent the fluid in the fluid flow pipe 310 from being concentrated in some areas and passing through it. The flow distribution portion 340 may include, for example, a distillation column.

4 is a view showing first and second capacitors of a mass flow controller according to a preferred embodiment of the present invention.

Referring to FIG. 4, the first and second plates 422 and 424 and the third and fourth plates 432 and 434 may be spaced apart by a predetermined distance d1 and d2. The first to fourth plates 422, 424, 432, and 434 are plate-shaped and their facing areas vary depending on the widths w1 and w2.

The first and second capacitance values measured through the first and second capacitors 420 and 430 pass between the first and second plates 422 and 424 and between the third and fourth plates 432 and 434 Density, and velocity of the fluid. Therefore, the capacitance of the fluid can be measured using the first and second capacitors 420 and 430, and the flow rate of the fluid can be measured using the measured capacitance.

The first and second plates 422 and 424 and the third and fourth plates 432 and 434 can control the facing area. Or the distance between the first and second plates 422 and 424 and the third and fourth plates 722 and 724 may be adjusted.

The first to fourth plates 422, 424, 432, and 434 may be formed in the same area, and may be formed in different areas. Or the areas of the facing plates may be the same or may be different from each other. Also, the first and second plates 422 and 424 may be spaced apart at regular intervals or spaced at irregular intervals. Or the third and fourth plates 432 and 434 may be spaced apart at regular intervals, or may be spaced at unequally spaced intervals.

5 is a view showing a measuring circuit of the mass flow controller according to the preferred embodiment of the present invention.

Referring to FIG. 5, the measurement circuit 550 in the present invention may include a bridge circuit. The bridge circuit includes two fixed resistors 540 and 545 and first and second capacitors 520 and 530 and a power supply 510 to provide a capacitance through the first and second capacitors 520 and 530, The value can be measured. The measured capacitance value may be rectified, amplified, and transmitted to the flow rate measurement unit 560 through the amplification unit 557.

In the flow measuring unit 560, an algorithm for measuring the flow rate using the electrostatic capacitance value may be performed. The flow rate measuring unit 560 stores the capacitance value corresponding to the flow rate of the fluid as data, and the flow rate of the fluid can be measured by comparing the measured capacitance value with the stored data.

6 is a block diagram of a mass flow controller according to another embodiment of the present invention.

Referring to FIG. 6, the first and second capacitors 620 and 630 may further include a flow distribution unit 640. A flow distribution portion 640 may be provided between the first and second plates 622 and 624 and between the third and fourth plates 632 and 634. The flow distribution portion 640 may be provided with the first and second plates 632 and 634, The fluid passing between the second plates 622 and 624 and the third and fourth plates 632 and 634 can be evenly distributed.

Referring to FIG. 6A, the first and second plates 622 and 624 of the first capacitor 620 may be provided so as to be parallel to the direction in which the fluid moves. Here, a flow distribution portion 640 may be provided between the first and second plates 622 and 624. In addition, the third and fourth plates 632 and 634 of the second capacitor 630 may be provided so as to be perpendicular to the direction in which the fluid moves. And a flow distributor 640 may be provided between the third and fourth plates 632 and 634.

Referring to FIG. 6B, the first and second capacitors 620 and 630 may be provided in the same manner as in FIG. 6A. 6A, the flow distributor 640 may be provided not only in the first and second capacitors 620 and 630 but also between the first and second capacitors 620 and 630 . The fluid passing through the fluid moving tube 610 can be uniformly distributed by the fluid distribution portion 640. [

The flow distributor 640 may be provided in at least one or more positions between the first and second capacitors 620 and 630 or between the first and second capacitors 620 and 630. The number of the flow distribution portions 640 is not limited to the number shown in the drawings.

7 is a view showing a mass flow control device according to still another preferred embodiment of the present invention.

Referring to FIG. 7, the first and second capacitors 720 and 730 may be positioned variously with respect to the moving direction of the fluid.

Referring to FIG. 7A, the first and second plates 722 and 724 of the first capacitor 720 may be provided so as to be perpendicular to the direction in which the fluid moves. Also, the first and second plates 732 and 734 of the second capacitor 730 may be provided so as to face the same direction as the fluid moves. The first capacitor 720 and the second capacitor 730 may be provided in the same direction as the moving direction of the fluid or may be provided in different directions.

The flow distributor 740 may be provided in at least one of the first capacitor 720, the second capacitor 730, and the first and second capacitors 720 and 730.

7B, the first and second plates 722 and 724 of the first capacitor 720 and the third and fourth plates 732 and 734 of the second capacitor 730 are in fluid communication with each other As shown in FIG.

The flow distributor 740 may be included in at least one of the first capacitor 720, the second capacitor 730, and the first and second capacitors 720 and 730.

Referring to Figure 7C, the first and second plates 722 and 724 of the first capacitor 720 and the third and fourth plates 732 and 734 of the second capacitor 730 are fluid So as to be perpendicular to the moving direction.

The flow distributor 740 may be included in at least one of the first capacitor 720, the second capacitor 730, and the first and second capacitors 720 and 730.

FIG. 8 is a view showing a mass flow control device according to still another preferred embodiment of the present invention, and FIG. 9 is a view showing a cross section of the mass flow control device of FIG.

Referring to FIGS. 8 and 9, the first and second plates 822 and 824 of the first capacitor 820 may be provided in the fluid transfer pipe 810. In other words, the grooves 812 may be formed to face portions of the fluid transfer tubes 810, and the first and second plates 822 and 824 may be provided in the grooves 812. The first and second plates 822 and 824 can measure the capacitance value of the fluid passing through the inside of the fluid moving tube 810.

In addition, third and fourth plates 832 and 834 functioning as a second capacitor 830 may be provided in the fluid transfer pipe 810. The third and fourth plates 832, 834 may be positioned to be perpendicular to the direction of movement of the fluid.

The mounting directions of the first to fourth plates 822, 824, 832, and 834 are applicable to the various modified embodiments described above, and are not limited to the drawings. Also, although not shown in the drawings, the flow rate distributing unit may be provided as described above.

10 is a flowchart illustrating a method of controlling a flow rate of a fluid using a mass flow controller according to a preferred embodiment of the present invention.

Referring to FIG. 10, a fluid may be injected into the fluid flow tube to move the fluid into the fluid flow tube (S110). The fluid moved in step S110 may pass through the first capacitor included in the fluid moving tube. The measurement circuit may measure a first capacitance value of the fluid flowing inside the fluid flow pipe through the first capacitor (S120). The fluid having passed through the first capacitor can again pass through the second capacitor. The measurement circuit may measure a second capacitance value of the fluid flowing inside the fluid flow pipe through the second capacitor (S130). The flow rate measuring unit of the control unit receives the measured first and second capacitance values from the measuring circuit (S140). The first and second capacitance values are correlated with each other and also correlated with the permittivity, density, and velocity of the fluid. Therefore, the flow rate of the fluid moving along the inside of the fluid moving tube can be measured using the capacitance value of the fluid (S150).

After the flow rate of the fluid is measured, the controller determines whether to control the amount of fluid flowing into the fluid flow tube (S160). If it is determined that the flow rate of the fluid should be controlled, the control unit can control the opening and closing of the control valve. Opening and closing of the control valve is controlled so that the flow rate of the fluid can be controlled (S170).

For example, if it is determined that the amount of fluid moving inside the fluid flow pipe is larger than the reference amount, the control unit can control the motor so that the control valve can be closed. As the control valve is closed, the amount of fluid moving in the fluid flow conduit can be reduced. Or if it is determined that the amount of fluid moving inside the fluid flow pipe is less than the reference amount, the control unit can control the motor so that the control valve can be opened. The control unit may control the control valve to be completely opened or closed, or may control the opening and closing degree of the control valve. The opening and closing degree of the control valve can be determined according to the flow rate to be controlled.

The first capacitor and the second capacitor may be simultaneously driven to measure the electrostatic capacitance of the fluid, and the first capacitor and the second capacitor may be sequentially driven to measure the electrostatic capacitance of the fluid.

The foregoing detailed description should not be construed in any way as being restrictive and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

Claims (11)

A first capacitor located on a path of fluid movement;
A second capacitor spaced apart from the first capacitor and positioned on a path of the fluid;
A measurement circuit coupled to the first and second capacitors and measuring the first and second capacitances of the fluid through the first and second capacitors; And
And a controller for measuring and controlling a flow rate of the fluid moving on the movement path of the fluid based on the capacitance value measured from the measurement circuit.
The method according to claim 1,
Wherein each of the first capacitor and the second capacitor includes:
A pair of first and second plates and a pair of third and fourth plates provided so as to face each other and spaced apart from each other.
3. The method of claim 2,
Wherein at least one of the first capacitor and the second capacitor comprises:
Wherein the mass flow controller is located inside the fluid flow pipe including the fluid flow path.
3. The method of claim 2,
Wherein at least one pair of the first and second plates and the pair of third and fourth plates is a plate,
Wherein the fluid is located in the same direction as the direction in which the fluid moves, or in a direction different from a direction in which the fluid moves.
3. The method of claim 2,
Wherein a distance between the plates provided on at least one pair of the pair of first and second plates and the pair of third and fourth plates is a distance
A mass flow controller using capacitive measurement that is spaced apart at regular intervals or spaced at uneven intervals.
The method according to claim 1,
Wherein the measuring circuit comprises:
A mass flow controller using capacitance measurement including a bridge circuit.
3. The method of claim 2,
Further comprising a flow distributing unit provided at least one of the first and second plates and between the third and fourth plates for distributing the flow of the fluid.
8. The method of claim 7,
Wherein the flow-
Mass flow controller using capacitance measurement including distillation column.
The method according to claim 1,
And a control valve controlling the flow rate of the fluid moving on the fluid movement path by controlling the opening and closing according to the control unit.
Moving the fluid into the fluid flow tube;
Measuring a first capacitance value of the fluid using a first capacitor of a mass flow controller according to any one of claims 1 to 9;
Measuring a second capacitance value of the fluid using a second capacitor of the mass flow controller according to any one of claims 1 to 9;
Transferring first and second capacitance values measured by the first and second capacitors to a controller;
Measuring a flow rate of the fluid at the control unit based on the measured first and second capacitance values; And
And controlling the flow rate of the fluid in the control unit.
11. The method of claim 10,
Wherein,
The first and second capacitances are sequentially measured using the first and second capacitors or the capacitances for measuring the first and second capacitances simultaneously using the first and second capacitors, Flow control method using mass flow control device using measurement.

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