Flow control valve and mass flow controller

Abstract

The invention provides a flow control valve and a mass flow controller, the flow control valve comprises an air supply assembly, a cavity assembly, a valve port and a flow control assembly, the cavity assembly is internally provided with an air cavity, and the side, facing the valve port, of the cavity assembly is provided with an elastic diaphragm and a valve rod connected to the elastic diaphragm; the valve port is provided with a central inflow hole and at least one edge outflow hole, the flow control assembly is connected with the valve rod, and the flow control assembly is provided with a sealing face used for blocking the central inflow hole; the air supply assembly communicates with the air cavity and is used for adjusting the air pressure in the air cavity so as to drive the elastic diaphragm and drive the valve rod and the flow control assembly to move, so that the sealing face is close to or away from the central inflow hole, and the flow of fluid flowing to the edge outflow holes through the central inflow hole is changed. The valve block is driven by gas pressure in the gas cavity to move, the opening degree of the flow control valve is changed, the precision of the flow detection device of the mass flow controller cannot be affected by heating and other reasons, and then the stability of the mass flow controller is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor process equipment, and in particular to a flow control valve and a mass flow controller. Background Art

[0002] Mass flow controllers are mainly used to precisely measure and control the mass flow of gases. They are important in scientific research and production in various fields such as semiconductor microelectronics industry, special materials research and development, chemical industry, petroleum industry, medicine, environmental protection and vacuum.

[0003] The existing mass flow controller mainly includes connectors, gas channels, flow sensors, flow dividers, circuit boards, solenoid valves, etc. The flow sensor transmits the detected flow signal to the circuit board, and then sends instructions to the solenoid valve after comparing it with the target flow. The solenoid valve then adjusts the flow until the flow detected by the flow sensor is equal to the target flow. However, the existing mass flow controllers often have unstable performance problems.

[0004] Therefore, how to provide a mass flow controller with stable performance has become a technical problem to be solved urgently in this field. Summary of the invention

[0005] The present invention aims to provide a flow control valve and a mass flow controller, wherein the flow control valve can ensure the stability of the mass flow controller.

[0006] To achieve the above object, as one aspect of the present invention, a flow control valve is provided, comprising an air supply component, a cavity component, a valve port and a flow control component, wherein:

[0007] The cavity assembly has an air cavity inside, and the cavity assembly has an elastic diaphragm and a valve stem connected to the elastic diaphragm on one side facing the valve port;

[0008] The valve port has a central inlet hole and at least one edge outlet hole, the flow control component is connected to the valve stem, and the flow control component has a sealing surface for blocking the central inlet hole;

[0009] The air supply assembly is connected to the air cavity and is used to adjust the gas pressure in the air cavity to drive the elastic diaphragm and drive the valve stem and the flow control assembly to move, so that the sealing surface is close to or away from the central inlet hole to change the flow rate of the fluid flowing from the central inlet hole to the edge outlet hole.

[0010] Optionally, the valve port includes an isolation cylinder and a flow control plate, the flow control plate is arranged inside the isolation cylinder and perpendicular to the axis of the isolation cylinder, the central inlet hole is formed in the flow control plate, the edge outlet hole penetrates the cylinder wall of the isolation cylinder and is located on the side of the flow control plate facing the cavity assembly, and an annular protrusion surrounding the central inlet hole is also formed on the side of the flow control plate facing the sealing surface, and the sealing surface is used to contact the annular protrusion to seal the central inlet hole.

[0011] Optionally, the flow control component includes a valve block and an elastic member, one end of the valve stem is fixedly connected to the elastic diaphragm, the other end of the valve stem can pass through the central inlet hole, the valve block is fixedly arranged on the valve stem, the sealing surface is located on the valve block, and the elastic member is used to drive the valve block to move toward the air cavity through elastic force.

[0012] Optionally, the valve block comprises a valve block body and a sealing ring, a first annular groove is formed on a side of the valve block body facing the annular protrusion, the sealing ring is arranged in the first annular groove, and the sealing surface is located on the sealing ring.

[0013] Optionally, the valve block is located on a side of the flow control plate away from the air cavity, a second annular groove is formed on the side of the valve block away from the air cavity, the elastic member is a spring, and one end of the elastic member is correspondingly arranged in the second annular groove.

[0014] Optionally, the valve block is located on the side of the flow control plate facing the air cavity, and a second annular groove is formed on the side of the valve block away from the air cavity. The elastic member is a spring, the elastic member is sleeved on the valve stem, and one end of the elastic member is correspondingly arranged in the second annular groove.

[0015] Optionally, the valve block is located on a side of the flow control plate facing the air cavity, and the flow control assembly also includes a transmission block, which is fixedly arranged on the valve stem and located on a side of the flow control plate away from the air cavity, and a third annular groove is formed on the side of the transmission block away from the flow control plate, and the elastic member is a spring, and one end of the elastic member is correspondingly arranged in the third annular groove.

[0016] Optionally, the cavity assembly includes a cavity and a deformable part, the bottom of the cavity is formed with a receiving groove, the bottom of the receiving groove is formed with an air groove, the deformable part includes a mounting tube, the elastic diaphragm and the valve stem, the mounting tube is sealed in the receiving groove so that the deformable part seals the air groove to form the air cavity.

[0017] Optionally, the mounting cylinder, the elastic diaphragm and the valve stem form an integral structure.

[0018] Optionally, the elastic diaphragm has a thickness of 0.3 mm-0.6 mm.

[0019] Optionally, a pressure feedback sensor is provided on the cavity assembly, and the pressure feedback sensor is used to detect the gas pressure in the air cavity.

[0020] As a second aspect of the present invention, a mass flow controller is provided, comprising a seat block, a flow detection device, a control device and the flow control valve described above, wherein a fluid passage is formed in the seat block, the flow detection device is used to detect the fluid flow in the fluid passage, the flow control valve is connected to the fluid passage, and the control device is used to control the opening of the flow control valve according to the fluid flow detected by the flow detection device so that the fluid flow reaches the flow setting value.

[0021] Optionally, the mass flow controller further comprises an outer cover, which is fixedly arranged on the seat block and sleeved on the outer sides of the control device, the flow detection device and the flow control valve;

[0022] The air supply assembly includes an air source control valve, an air supply pipeline and an air supply connector. The air supply pipeline is connected between the air supply connector and the air source control valve. The air source control valve is used to connect to the air source and control the amount of air supplied to the air cavity by the air source through the air supply pipeline and the air supply connector. The air source control valve is fixedly arranged on the outer cover.

[0023] In the flow control valve and mass flow controller provided by the present invention, the gas supply component can adjust the gas pressure in the gas cavity, so that the gas in the gas cavity pushes the elastic diaphragm to contract or expand and drives the valve stem to change position, thereby driving the sealing surface of the flow control component to seal or open the gas path at the central inlet hole, thereby realizing the flow regulation function of the valve. In the present invention, the flow control component is driven to move and change the opening of the flow control valve by the gas pressure in the gas cavity. When the mass flow controller is used for a long time or the valve is opened for baking, compared with the existing solenoid valve structure, the accuracy of the flow control valve itself or the accuracy of the flow detection device of the mass flow controller will not be affected by the heating of the coil and other reasons, thereby ensuring the stability of the mass flow controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 is a schematic structural diagram of a mass flow controller provided by an embodiment of the present invention;

[0026] Figure 2is a schematic diagram of a gas flow path in a mass flow controller provided by an embodiment of the present invention;

[0027] Figure 3 is a partial enlarged schematic diagram of a part of the structure of a flow control valve provided by an embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of some parts of a flow control valve provided by an embodiment of the present invention;

[0029] Figure 5 is a schematic diagram of some parts of a flow control valve provided by an embodiment of the present invention;

[0030] Figure 6 is a schematic diagram of some parts of a flow control valve provided by an embodiment of the present invention;

[0031] Figure 7 is a schematic diagram of some parts of a flow control valve provided by an embodiment of the present invention;

[0032] Figure 8 is a schematic diagram of some parts of a flow control valve provided by an embodiment of the present invention;

[0033] Fig. 9 is a schematic diagram of some parts of a flow control valve provided by an embodiment of the present invention;

[0034] Fig.10 is a schematic diagram of some parts of a flow control valve provided by an embodiment of the present invention;

[0035] Fig.11 is a schematic structural diagram of a mass flow controller provided by an embodiment of the present invention;

[0036] Fig.12 is a partial enlarged schematic diagram of a part of the structure of a flow control valve provided by another embodiment of the present invention;

[0037] Fig.13 It is a partially enlarged schematic diagram of a partial structure of a flow control valve provided in another embodiment of the present invention.

[0038] Description of reference numerals:

[0039] Air supply assembly 100

[0040] Air source control valve 110

[0041] Gas supply line 120

[0042] Gas supply connector 130

[0043] Cavity assembly 200

[0044] Air cavity 201

[0045] Cavity 210

[0046] Deformation 220

[0047] Installation tube 221

[0048] Elastic diaphragm 222

[0049] Valve stem 223

[0050] Pressure feedback sensor 230

[0051] Valve port 300

[0052] Flow control plate 310

[0053] Central inlet hole 311

[0054] Annular protrusion 312

[0055] Isolation tube 320

[0056] Edge outflow hole 321

[0057] Valve block 410

[0058] Valve block body 411

[0059] First annular groove 4111

[0060] Threaded through hole 4112

[0061] Sealing ring 412

[0062] Elastic member 420

[0063] Block 10

[0064] Seat block body 11

[0065] Air intake connector 12

[0066] Air outlet connector 13

[0067] Upstream Passage 101

[0068] Downstream passage 102

[0069] Flow detection device 20

[0070] Shunt 21

[0071] Flow sensor 22

[0072] Flow control valve 30

[0073] Control device 40

[0074] Cover 50 DETAILED DESCRIPTION

[0075] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0076] In existing mass flow controllers, the flow regulating part is usually a solenoid valve, which adjusts the flow rate based on the mutual conversion of electric field and magnetic field. Therefore, heat will inevitably be generated during the operation of the solenoid valve. The flow sensor adopts the thermal principle and measures the flow rate based on the heat carried away by the gas. Therefore, the heat generated by the solenoid valve will cause the measurement error of the flow sensor to increase. As the solenoid valve continues to generate heat during operation, the measurement error of the flow sensor will be further increased, resulting in zero drift and dynamic zero drift, resulting in poor control accuracy, and thus affecting the client's process. In addition, the mass flow controller production process requires the valve to be opened and the machine to be baked. The heat generated by the solenoid valve will cause the flow sensor to misjudge, thereby affecting the calibration accuracy and reducing production efficiency.

[0077] As one aspect of the present invention, a flow control valve 30 is provided. Figure 1 , Figure 3 As shown, the flow control valve 30 includes an air supply component 100, a cavity component 200, a valve port 300 and a flow control component 400, wherein:

[0078] The cavity assembly 200 has an air cavity 201 inside, and the side of the cavity assembly 200 facing the valve port 300 has an elastic diaphragm 222 and a valve stem 223 connected to the elastic diaphragm 222;

[0079] The valve port 300 has a central inlet hole 311 and at least one edge outlet hole 321, the flow control component 400 is connected to the valve stem 223, and the flow control component 400 has a sealing surface for blocking the central inlet hole;

[0080] The air supply assembly 100 is connected to the air cavity 201 and is used to adjust the gas pressure in the air cavity 201 to drive the elastic diaphragm 222 to drive the valve stem 223 and the flow control assembly 400 to move, so that the sealing surface is close to or away from the central inlet hole 311, so as to change the flow rate of the fluid flowing from the central inlet hole 311 to the edge outlet hole 321.

[0081] like Figure 2 FIG. 1 is a schematic diagram of a gas flow path in a flow control valve 30 provided by the present invention;

[0082] In the flow control valve 30 provided by the present invention, the gas supply component 100 can adjust the gas pressure in the gas cavity 201, so that the gas in the gas cavity 201 pushes the elastic diaphragm 222 to contract or expand and drives the valve stem 223 to change position, thereby driving the sealing surface of the flow control component 400 to seal or open the gas path at the central inlet hole 311, thereby realizing the flow regulation function of the valve. In the present invention, the flow control component 400 is driven to move and change the opening of the flow control valve 30 by the gas pressure in the gas cavity 201. When the mass flow controller is used for a long time or the valve is opened to bake the machine, compared with the existing solenoid valve structure, the accuracy of the flow control valve 30 itself or the accuracy of the flow detection device 20 of the mass flow controller will not be affected by the heating of the coil, thereby ensuring the stability of the mass flow controller.

[0083] As an optional embodiment of the present invention, Figure 3 , Fig.12 , Fig.13 As shown, the valve port 300 includes an isolation cylinder 320 and a flow control plate 310, the flow control plate 310 is arranged inside the isolation cylinder 320 and perpendicular to the axis of the isolation cylinder 320, a central inlet hole 311 is formed in the flow control plate 310, an edge outlet hole 321 penetrates the cylinder wall of the isolation cylinder 320 and is located on the side of the flow control plate 310 facing the cavity assembly 200, and an annular protrusion 312 surrounding the central inlet hole 311 is also formed on the side of the flow control plate 310 facing the sealing surface, and the sealing surface is used to contact the annular protrusion 312 to seal the central inlet hole 311.

[0084] In order to improve the stability of the flow control valve in controlling the fluid flow, as a preferred embodiment of the present invention, as Figure 3 , Fig.12 , Fig.13 As shown, the flow control component includes a valve block 410 and an elastic member 420, one end of the valve stem 223 is fixedly connected to the elastic diaphragm 222, and the other end of the valve stem 223 can pass through the central inlet hole 311, the valve block 410 is fixedly arranged on the valve stem 223, and the sealing surface is located on the valve block 410, and the elastic member 420 is used to drive the valve block 410 to move toward the air cavity 201 through elastic force.

[0085] In an embodiment of the present invention, the flow control component includes an elastic member 420, which can drive the valve block 410 through elastic force to resist the thrust generated by the expansion of the air cavity 201, and ensure that the forces on the upper and lower sides of the valve block 410 are balanced in real time, thereby ensuring the smooth movement of the valve block 410, and further improving the stability of the flow control valve in controlling the fluid flow.

[0086] In order to ensure the air tightness of the flow control valve 30, as a preferred embodiment of the present invention, Figure 3 , Figure 8As shown, a first annular groove 4111 is formed on one side of the valve block 410 facing the annular protrusion 312 , and a sealing ring 412 is disposed in the first annular groove 4111 . The sealing ring 412 is used to contact the annular protrusion 312 correspondingly to seal the central inlet hole 311 .

[0087] In an embodiment of the present invention, the valve block 410 includes a valve block body 411 and a sealing ring 412. A first annular groove 4111 is formed on the side of the valve block body 411 facing the annular protrusion 312. The sealing ring 412 is arranged in the first annular groove 4111. The sealing surface is located on the sealing ring 412, so that the elastic sealing ring 412 is abutted against the annular protrusion 312 and blocks the central inlet hole 311, thereby ensuring the air tightness of the flow control valve 30.

[0088] As an optional implementation of the present invention, the sealing ring 412 is made of rubber.

[0089] In order to ensure the stability of the position of the elastic member 420, as a preferred embodiment of the present invention, Figure 3 As shown, a second annular groove is formed on the side of the valve block 410 away from the annular protrusion 312, such as Figure 3 , Fig.10 As shown, the elastic member 420 is a spring, and one end of the elastic member 420 is correspondingly arranged in the second annular groove.

[0090] As an optional embodiment of the present invention, the valve stem 223 and the valve block 410 can be connected by threaded fitting. Specifically, Figure 3 , Fig. 9 As shown, a threaded through hole 4112 coaxial with the valve block 410 is formed in the valve block 410 , and the end of the valve stem 223 has an external thread, and the end of the valve stem 223 is screwed into the threaded through hole 4112 .

[0091] As another optional embodiment of the present invention, Fig.12 As shown, the valve block 410 is located on the side of the flow control plate 310 facing the air cavity 201, and a second annular groove is formed on the side of the valve block 410 away from the air cavity 201. The elastic member 420 is a spring, and the elastic member 420 is sleeved on the valve stem 223, and one end of the elastic member 420 is correspondingly arranged in the second annular groove.

[0092] As another optional embodiment of the present invention, Fig.13 As shown, the valve block 410 is located on the side of the flow control plate 310 facing the air cavity 201, and the flow control assembly also includes a transmission block 430, which is fixedly arranged on the valve stem 223 and is located on the side of the flow control plate 310 away from the air cavity 201, and a third annular groove is formed on the side of the transmission block 430 away from the flow control plate 310, and the elastic member 420 is a spring, and one end of the elastic member 420 is correspondingly arranged in the third annular groove.

[0093] As an optional embodiment of the present invention, Figure 3 , Figure 5 As shown, the cavity assembly 200 includes a cavity 210 and a deformable member 220. A receiving groove is formed at the bottom of the cavity 210, and an air groove is formed at the bottom of the receiving groove. The deformable member 220 includes a mounting tube 221, an elastic diaphragm 222 and a valve stem 223. The mounting tube 221 is sealed in the receiving groove so that the deformable member 220 seals the air groove to form an air cavity 201.

[0094] To further ensure the air tightness of the flow control valve 30, as a preferred embodiment of the present invention, Figure 3 , Figure 6 As shown, the mounting cylinder 221 , the elastic diaphragm 222 and the valve stem 223 form an integrated structure, thereby avoiding the occurrence of gaps on the mating surface near the diaphragm due to low structural strength of the diaphragm, and further ensuring the air tightness of the flow control valve 30 .

[0095] As an optional embodiment of the present invention, the thickness of the elastic diaphragm 222 is 0.3 mm-0.6 mm.

[0096] As an optional implementation of the present invention, the deformable member 220 is made of metal.

[0097] As an optional embodiment of the present invention, Figure 3 , Figure 7 As shown, a pressure feedback sensor 230 is provided on the cavity assembly 200 , and the pressure feedback sensor 230 is used to detect the gas pressure in the gas cavity 201 , so that the control device of the mass flow controller controls the gas supply assembly 100 according to the gas pressure feedback from the pressure feedback sensor 230 .

[0098] As an optional embodiment of the present invention, Figure 1 , Figure 3 , Figure 5 , Fig.12 , Fig.13 As shown, a plurality of joint mounting holes 211 are formed on the top of the cavity 210, and the air supply joint 130 and the pressure feedback sensor 230 are connected to the inside of the cavity 210 through the joint mounting holes 211 one by one. The cavity 210 is also formed with fastening mounting holes 212 distributed around the receiving groove, and the cavity 210 is fixedly connected to the seat block 10 through fasteners passing through the fastening mounting holes 212.

[0099] As an optional embodiment of the present invention, Figure 1 , Figure 4As shown, the air supply assembly 100 includes an air source control valve 110, an air supply pipeline 120 and an air supply connector 130. The air supply pipeline 120 is connected between the air supply connector 130 and the air source control valve 110. The air source control valve 110 is used to connect to the air source and control the amount of air supplied to the air cavity 201 by the air supply pipeline 120 and the air supply connector 130.

[0100] In order to improve the air tightness of the flow control valve 30 structure, as a preferred embodiment of the present invention, Figure 3 As shown, a first sealing ring groove is formed on the end surface of the isolation cylinder 320 facing the elastic member 420, and a first O-ring 610 is arranged in the first sealing ring groove.

[0101] In order to improve the air tightness of the flow control valve 30 structure, as a preferred embodiment of the present invention, Figure 3 As shown, a second sealing ring groove is formed on the end surface of the installation tube 221 facing the air cavity 201, and a second O-ring 620 is arranged in the second sealing ring groove.

[0102] As a second aspect of the present invention, a mass flow controller is provided, such as Figure 1 As shown, the mass flow controller includes a seat block 10, a flow detection device 20, a control device 40 and a flow control valve 30 in front. A fluid passage is formed in the seat block 10. The flow detection device 20 is used to detect the fluid flow in the fluid passage. The flow control valve 30 is connected to the fluid passage. The control device 40 is used to control the opening of the flow control valve 30 according to the fluid flow detected by the flow detection device 20 so that the fluid flow reaches the flow setting value.

[0103] In the mass flow controller provided by the present invention, the gas supply component 100 of the flow control valve 30 can adjust the gas pressure in the gas cavity 201, so that the gas in the gas cavity 201 pushes the elastic diaphragm 222 to contract or expand and drives the valve stem 223 to change position, thereby driving the sealing surface of the flow control component 400 to seal or open the gas path at the central inlet hole 311, thereby realizing the flow regulation function of the valve. In the present invention, the flow control component 400 is driven to move and change the opening of the flow control valve 30 by the gas pressure in the gas cavity 201. When the mass flow controller is used for a long time or the valve is opened for baking, compared with the existing solenoid valve structure, the accuracy of the flow control valve 30 itself or the accuracy of the flow detection device 20 of the mass flow controller will not be affected by the heating of the coil, thereby ensuring the stability of the mass flow controller. .

[0104] As an optional embodiment of the present invention, Figure 1 , Figure 3As shown, the seat block 10 includes a seat block body 11, an air inlet connector 12 and an air outlet connector 13, a fluid passage is formed in the seat block body 11, the air inlet connector 12 is connected to the inlet end of the fluid passage, and the air outlet connector 13 is connected to the outlet end of the fluid passage.

[0105] As an optional embodiment of the present invention, Figure 1 , Figure 3 As shown, the fluid passage includes an upstream passage 101 and a downstream passage 102, a valve mounting groove is formed on the seat block body 11, an elastic member mounting groove is formed at the bottom of the valve mounting groove, the upstream passage 101 and the downstream passage 102 are respectively connected to the side walls of the valve mounting groove and the elastic member mounting groove, the isolation cylinder 320 of the valve port 300 is arranged in the valve mounting groove, and a flow gap is provided between the outer wall of the isolation cylinder 320 and the side wall of the valve mounting groove, and the elastic member 420 is arranged in the elastic member mounting groove; the cavity assembly 200 is fixedly arranged on the seat block body 11 and seals the opening of the valve mounting groove on the seat block surface.

[0106] In order to ensure the airtightness of the mass flow controller, as a preferred embodiment of the present invention, Figure 3 As shown, a third sealing ring groove surrounding the valve installation groove opening is also formed on the surface of the seat block body 11, and a third O-ring 630 is arranged in the third sealing ring groove.

[0107] As an optional embodiment of the present invention, Figure 1 , Figure 3 As shown, the flow detection device 20 includes a diverter 21 and a flow sensor 22. The diverter 21 and the retaining ring are sequentially arranged in the fluid passage along the fluid flow direction. The diverter 21 is used to divert part of the fluid to the flow sensor 22. The flow sensor 22 is used to detect the fluid flow passing through itself to determine the fluid flow in the fluid passage.

[0108] As an optional embodiment of the present invention, Figure 1 , Figure 3 As shown, the mass flow controller further includes an outer cover 50 , which is fixedly disposed on the seat block 10 and sleeved on the outer sides of the control device 40 , the flow detection device 20 and the flow control valve 30 .

[0109] As an optional embodiment of the present invention, Figure 1 , Figure 3 , Fig.11As shown, the air supply assembly 100 includes an air source control valve 110, an air supply pipeline 120 and an air supply connector 130. The air supply pipeline 120 is connected between the air supply connector 130 and the air source control valve 110. The air source control valve 110 is used to connect to the air source and control the amount of air supplied to the air cavity 201 through the air supply pipeline 120 and the air supply connector 130. The air source control valve 110 is fixedly arranged on the outer cover 50.

[0110] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A flow control valve, characterized in that: It includes an air supply component, a cavity component, a valve port and a flow control component, wherein: The cavity assembly has an air cavity inside, and the cavity assembly has an elastic diaphragm and a valve stem connected to the elastic diaphragm on one side facing the valve port; The valve port has a central inlet hole and at least one edge outlet hole, the flow control component is connected to the valve stem, and the flow control component has a sealing surface for blocking the central inlet hole; The air supply assembly is connected to the air cavity and is used to adjust the gas pressure in the air cavity to drive the elastic diaphragm and drive the valve stem and the flow control assembly to move, so that the sealing surface is close to or away from the central inlet hole to change the flow rate of the fluid flowing from the central inlet hole to the edge outlet hole.

2. The flow control valve according to claim 1, characterized in that: The valve port includes an isolation cylinder and a flow control plate, wherein the flow control plate is arranged inside the isolation cylinder and perpendicular to the axis of the isolation cylinder, the central inlet hole is formed in the flow control plate, the edge outlet hole penetrates the cylinder wall of the isolation cylinder and is located on the side of the flow control plate facing the cavity assembly, and an annular protrusion surrounding the central inlet hole is also formed on the side of the flow control plate facing the sealing surface, and the sealing surface is used to contact the annular protrusion to seal the central inlet hole.

3. The flow control valve according to claim 2, characterized in that: The flow control component includes a valve block and an elastic member, one end of the valve stem is fixedly connected to the elastic diaphragm, the other end of the valve stem can pass through the central inlet hole, the valve block is fixedly arranged on the valve stem, the sealing surface is located on the valve block, and the elastic member is used to drive the valve block to move toward the air cavity through elastic force.

4. The flow control valve according to claim 3, characterized in that: The valve block comprises a valve block body and a sealing ring. A first annular groove is formed on a side of the valve block body facing the annular protrusion. The sealing ring is arranged in the first annular groove. The sealing surface is located on the sealing ring.

5. The flow control valve according to claim 3, characterized in that: The valve block is located on a side of the flow control plate away from the air cavity, a second annular groove is formed on the side of the valve block away from the air cavity, the elastic member is a spring, and one end of the elastic member is correspondingly arranged in the second annular groove.

6. The flow control valve according to claim 3, characterized in that: The valve block is located on the side of the flow control plate facing the air cavity, and a second annular groove is formed on the side of the valve block away from the air cavity. The elastic member is a spring, which is sleeved on the valve stem, and one end of the elastic member is correspondingly arranged in the second annular groove.

7. The flow control valve according to claim 3, characterized in that: The valve block is located on the side of the flow control plate facing the air cavity. The flow control assembly also includes a transmission block, which is fixedly arranged on the valve stem and located on the side of the flow control plate away from the air cavity. A third annular groove is formed on the side of the transmission block away from the flow control plate. The elastic member is a spring, and one end of the elastic member is correspondingly arranged in the third annular groove.

8. The flow control valve according to any one of claims 1 to 7, characterized in that: The cavity assembly includes a cavity and a deformable part, a receiving groove is formed at the bottom of the cavity, an air groove is formed at the bottom of the receiving groove, the deformable part includes a mounting tube, the elastic diaphragm and the valve stem, and the mounting tube is sealed in the receiving groove so that the deformable part seals the air groove to form the air cavity.

9. The flow control valve according to claim 8, characterized in that: The mounting cylinder, the elastic diaphragm and the valve stem form an integral structure.

10. The flow control valve according to claim 8, characterized in that: The thickness of the elastic diaphragm is 0.3mm-0.6mm.

11. The flow control valve according to any one of claims 1 to 7, characterized in that: The cavity assembly is provided with a pressure feedback sensor, and the pressure feedback sensor is used to detect the gas pressure in the gas cavity.

12. A mass flow controller, characterized in that: It comprises a seat block, a flow detection device, a control device and a flow control valve as described in any one of claims 1 to 11, wherein a fluid passage is formed in the seat block, the flow detection device is used to detect the fluid flow in the fluid passage, the flow control valve is connected to the fluid passage, and the control device is used to control the opening of the flow control valve according to the fluid flow detected by the flow detection device so that the fluid flow reaches a flow setting value.

13. The mass flow controller according to claim 12, characterized in that: The mass flow controller further comprises an outer cover, which is fixedly arranged on the seat block and sleeved on the outer sides of the control device, the flow detection device and the flow control valve; The air supply assembly includes an air source control valve, an air supply pipeline and an air supply connector. The air supply pipeline is connected between the air supply connector and the air source control valve. The air source control valve is used to connect to the air source and control the amount of air supplied to the air cavity by the air source through the air supply pipeline and the air supply connector. The air source control valve is fixedly arranged on the outer cover.

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