Flow control valve and mass flow controller

Abstract

This invention provides a flow control valve and a mass flow controller. The flow control valve includes a gas supply assembly, a cavity assembly, a valve port, and a flow control assembly. The cavity assembly has an internal gas chamber, and an elastic diaphragm and a valve stem connected to the elastic diaphragm are located on the side of the cavity assembly facing the valve port. The valve port has a central inlet and at least one edge outlet. The flow control assembly is connected to the valve stem and has a sealing surface for sealing the central inlet. The gas supply assembly communicates with the gas chamber and is used to regulate the gas pressure in the gas chamber to drive the elastic diaphragm and move the valve stem and flow control assembly, causing the sealing surface to move closer to or further away from the central inlet, thereby changing the flow rate of fluid flowing from the central inlet to the edge outlet. This invention drives the valve block to move and change the opening of the flow control valve through the gas pressure in the gas chamber, preventing the accuracy of the flow detection device of the mass flow controller from being affected by heat generation or other factors, thus ensuring the stability of the mass flow controller.

Description

Technical Field

[0001] This invention relates to the field of semiconductor process equipment, and more specifically, to a flow control valve and a mass flow controller. Background Technology

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

[0003] Existing mass flow controllers mainly consist of connectors, gas passages, flow sensors, splitters, circuit boards, and solenoid valves. The flow sensor transmits the detected flow signal to the circuit board, which then compares it with the target flow rate and sends a command to the solenoid valve. The solenoid valve then adjusts the flow rate until the flow rate detected by the flow sensor equals the target flow rate. However, existing mass flow controllers often suffer from performance instability.

[0004] Therefore, how to provide a stable mass flow controller has become a technical problem that urgently needs to be solved 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 objectives, as one aspect of the present invention, a flow control valve is provided, comprising an air supply assembly, a cavity assembly, a valve port, and a flow control assembly, wherein,

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

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

[0009] The gas supply component is connected to the gas chamber and is used to adjust the gas pressure in the gas chamber to drive the elastic diaphragm and move the valve stem and the flow control component, so that the sealing surface moves closer to or further away from the central inlet hole, thereby changing the flow rate of 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 disposed 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. The side of the flow control plate facing the sealing surface also has an annular protrusion surrounding the central inlet hole. The sealing surface is used to contact the annular protrusion to block the central inlet hole.

[0011] Optionally, the flow control assembly includes a valve block and an elastic element. One end of the valve stem is fixedly connected to the elastic diaphragm, and the other end of the valve stem can pass through the central inlet hole. The valve block is fixedly mounted on the valve stem, and the sealing surface is located on the valve block. The elastic element is used to drive the valve block to move toward the air chamber by elastic force.

[0012] Optionally, the valve block includes a valve block body and a sealing ring. The valve block body has a first annular groove formed on the side facing the annular protrusion. The sealing ring is disposed in the first annular groove, and the sealing surface is located on the sealing ring.

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

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

[0015] Optionally, the valve block is located on the side of the flow control plate facing the air chamber. The flow control assembly further includes a transmission block, which is fixedly mounted on the valve stem and located on the side of the flow control plate away from the air chamber. A third annular groove is formed on the side of the transmission block away from the flow control plate. The elastic element is a spring, and one end of the elastic element is correspondingly disposed in the third annular groove.

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

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

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

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

[0020] As a second aspect of the present invention, a mass flow controller is provided, including a seat, a flow detection device, a control device, and the aforementioned flow control valve. A fluid passage is formed in the seat, the flow detection device is used to detect the fluid flow rate in the fluid passage, the flow control valve is connected to the fluid passage, and the control device is used to control the opening degree of the flow control valve according to the fluid flow rate detected by the flow detection device, so that the fluid flow rate reaches a set flow rate value.

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

[0022] The gas supply assembly includes a gas source control valve, a gas supply pipeline, and a gas supply connector. The gas supply pipeline is connected between the gas supply connector and the gas source control valve. The gas source control valve is used to connect to a gas source and control the amount of gas supplied by the gas source to the gas chamber through the gas supply pipeline and the gas supply connector. The gas source control valve is fixedly mounted on the outer cover.

[0023] In the flow control valve and mass flow controller provided by this invention, the gas supply component can adjust the gas pressure in the gas chamber, causing the gas in the gas chamber to push the elastic diaphragm to contract or expand and drive the valve stem to change position. This, in turn, drives the sealing surface of the flow control component to seal or open the gas passage at the central inlet, thereby realizing the flow regulation function of the valve. In this invention, the flow control component is driven to move and change the opening degree of the flow control valve by the gas pressure in the gas chamber. Compared with the existing solenoid valve structure, during long-term use of the mass flow controller or during valve-on-demand heating, 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 coil heating or other reasons, thus ensuring the stability of the mass flow controller. Attached Figure Description

[0024] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

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

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

[0027] Figure 3 This is a partially enlarged schematic diagram of a portion of the structure of the flow control valve provided in an embodiment of the present invention;

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

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

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

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

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

[0033] Figure 9 This is a schematic diagram of some parts of the flow control valve provided in an embodiment of the present invention;

[0034] Figure 10 This is a schematic diagram of some parts of the flow control valve provided in an embodiment of the present invention;

[0035] Figure 11 This is a schematic diagram of the mass flow controller provided in an embodiment of the present invention;

[0036] Figure 12 This is a partially enlarged schematic diagram of a flow control valve according to another embodiment of the present invention;

[0037] Figure 13 This is a partially enlarged schematic diagram of a flow control valve according to another embodiment of the present invention.

[0038] Explanation of reference numerals in the attached figures:

[0039] Gas supply assembly 100

[0040] Gas 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 component 220

[0047] Mounting cylinder 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 311

[0054] Annular protrusion 312

[0055] 320 isolation cylinder

[0056] Edge outlet orifice 321

[0057] Valve block 410

[0058] Valve block body 411

[0059] First annular groove 4111

[0060] 4112 threaded through hole

[0061] Sealing ring 412

[0062] Elastic element 420

[0063] Seat block 10

[0064] Seat block body 11

[0065] Inlet connector 12

[0066] Air outlet connector 13

[0067] Upstream Pathway 101

[0068] Downstream Pathway 102

[0069] Flow detection device 20

[0070] Diverter 21

[0071] Flow sensor 22

[0072] Flow control valve 30

[0073] Control device 40

[0074] Outer cover 50 Detailed Implementation

[0075] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0076] In existing mass flow controllers, the flow regulation component is typically a solenoid valve, which regulates flow based on the interconversion of electric and magnetic fields. Therefore, solenoid valves inevitably generate heat during operation. Flow sensors, which operate on a thermal principle, measure flow based on the heat carried away by the gas. Consequently, the heat generated by the solenoid valve increases the flow sensor's measurement error. As the solenoid valve continues to generate heat during operation, this error further increases, leading to zero drift and dynamic zero-point drift, resulting in poor control accuracy and impacting the customer's manufacturing process. Furthermore, the mass flow controller manufacturing process requires valve opening and heat treatment; the heat generated by the solenoid valve can cause the flow sensor to misinterpret data, affecting calibration accuracy and reducing production efficiency.

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

[0078] The cavity assembly 200 has an air chamber 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 assembly 400 is connected to the valve stem 223 and has a sealing surface for blocking the central inlet hole.

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

[0081] like Figure 2 The diagram shows the gas flow path in the flow control valve 30 provided by the present invention.

[0082] In the flow control valve 30 provided by this invention, the gas supply component 100 can adjust the gas pressure in the gas chamber 201, causing the gas in the gas chamber 201 to push the elastic diaphragm 222 to contract or expand and drive the valve stem 223 to change position. This, in turn, drives the sealing surface of the flow control component 400 to seal or open the gas passage at the central inlet hole 311, thereby realizing the flow regulation function of the valve. In this invention, the flow control component 400 is driven to move and change the opening degree of the flow control valve 30 by the gas pressure in the gas chamber 201. Compared with the existing solenoid valve structure, when the mass flow controller is used for a long time or when the valve is opened for heating, 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 coil heating or other reasons, thus ensuring the stability of the mass flow controller.

[0083] As an optional embodiment of the present invention, such as Figure 3 , Figure 12 , Figure 13 As shown, the valve port 300 includes an isolation cylinder 320 and a flow control plate 310. The flow control plate 310 is disposed 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. 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. The sealing surface is used to contact the annular protrusion 312 to seal the central inlet hole 311.

[0084] To improve the stability of the flow rate controlled by the flow control valve, as a preferred embodiment of the present invention, such as... Figure 3 , Figure 12 , Figure 13 As shown, the flow control assembly includes a valve block 410 and an elastic element 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 mounted on the valve stem 223, and the sealing surface is located on the valve block 410. The elastic element 420 is used to drive the valve block 410 to move toward the air chamber 201 by elastic force.

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

[0086] To ensure the airtightness of the flow control valve 30, as a preferred embodiment of the present invention, such as... Figure 3 , Figure 8As shown, a first annular groove 4111 is formed on the side of the valve block 410 facing the annular protrusion 312. A sealing ring 412 is provided in the first annular groove 4111. The sealing ring 412 is used to contact the annular protrusion 312 to seal the central inlet hole 311.

[0087] In this embodiment of the invention, the valve block 410 includes a valve block body 411 and a sealing ring 412. The valve block body 411 has a first annular groove 4111 formed on the side facing the annular protrusion 312. The sealing ring 412 is disposed in the first annular groove 4111, and the sealing surface is located on the sealing ring 412. Thus, the elastic sealing ring 412 abuts against the annular protrusion 312 and blocks the central inlet hole 311, ensuring the airtightness of the flow control valve 30.

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

[0089] To ensure the stability of the position of the elastic element 420, as a preferred embodiment of the present invention, such as... Figure 3 As shown, a second annular groove is formed on the side of the valve block 410 opposite to the annular protrusion 312, as... Figure 3 , Figure 10 As shown, the elastic element 420 is a spring, and one end of the elastic element 420 is correspondingly disposed 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 a threaded connection, specifically, as shown in the example below. Figure 3 , Figure 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, such as Figure 12 As shown, the valve block 410 is located on the side of the flow control plate 310 facing the air chamber 201, and a second annular groove is formed on the side of the valve block 410 away from the air chamber 201. The elastic element 420 is a spring, which is sleeved on the valve stem 223, and one end of the elastic element 420 is correspondingly set in the second annular groove.

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

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

[0094] To further ensure the airtightness of the flow control valve 30, as a preferred embodiment of the present invention, such as... Figure 3 , Figure 6 As shown, the mounting cylinder 221, the elastic diaphragm 222 and the valve stem 223 are formed into an integral structure, thereby avoiding gaps in the mating surface near the diaphragm due to the low strength of the diaphragm structure, and further ensuring the airtightness of the flow control valve 30.

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

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

[0097] As an optional embodiment of the present invention, such as Figure 3 , Figure 7 As shown, a pressure feedback sensor 230 is provided on the cavity assembly 200. 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 can control the gas supply assembly 100 according to the gas pressure fed back by the pressure feedback sensor 230.

[0098] As an optional embodiment of the present invention, such as Figure 1 , Figure 3 , Figure 5 , Figure 12 , Figure 13 As shown, the top of the cavity 210 has multiple connector mounting holes 211, and the air supply connector 130 and the pressure feedback sensor 230 are connected to the inside of the cavity 210 through the connector mounting holes 211 respectively. The cavity 210 also has fastening mounting holes 212 distributed around the receiving groove, and the cavity 210 is fixedly connected to the seat block 10 by fasteners passing through the fastening mounting holes 212.

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

[0100] To improve the airtightness of the flow control valve 30 structure, as a preferred embodiment of the present invention, such as... Figure 3 As shown, a first sealing ring groove is formed on the end face of the isolation cylinder 320 facing the elastic member 420, and a first O-ring 610 is provided in the first sealing ring groove.

[0101] To improve the airtightness of the flow control valve 30 structure, as a preferred embodiment of the present invention, such as... Figure 3 As shown, a second sealing ring groove is formed on the end face of the mounting cylinder 221 facing the air chamber 201, and a second O-ring 620 is provided 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. A fluid passage is formed in the seat block 10. The flow detection device 20 is used to detect the fluid flow rate 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 degree of the flow control valve 30 according to the fluid flow rate detected by the flow detection device 20, so that the fluid flow rate reaches the set flow rate value.

[0103] In the mass flow controller provided by this invention, the air supply component 100 of the flow control valve 30 can adjust the gas pressure in the air chamber 201, causing the gas in the air chamber 201 to push the elastic diaphragm 222 to contract or expand and drive the valve stem 223 to change position. This, in turn, drives the sealing surface of the flow control component 400 to seal or open the air passage at the central inlet hole 311, thereby realizing the valve's flow regulation function. In this invention, the gas pressure in the air chamber 201 drives the flow control component 400 to move and change the opening degree of the flow control valve 30. Compared with existing solenoid valve structures, during long-term use or when the mass flow controller is being heated, 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 coil heating or other reasons, thus ensuring the stability of the mass flow controller.

[0104] As an optional embodiment of the present invention, such as 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, such as 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, and an elastic element 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 element mounting groove. The isolation cylinder 320 of the valve port 300 is disposed in the valve mounting groove, and there is a flow gap between the outer wall of the isolation cylinder 320 and the side wall of the valve mounting groove. The elastic element 420 is disposed in the elastic element mounting groove. The cavity assembly 200 is fixedly disposed on the seat block body 11 and seals the opening of the valve mounting groove on the surface of the seat block.

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

[0107] As an optional embodiment of the present invention, such as Figure 1 , Figure 3 As shown, the flow detection device 20 includes a flow divider 21 and a flow sensor 22. The flow divider 21 and the baffle ring are arranged sequentially in the fluid passage along the fluid flow direction. The flow divider 21 is used to divert part of the fluid to the flow sensor 22. The flow sensor 22 is used to detect the flow rate of the fluid flowing through it in order to determine the flow rate of the fluid in the fluid passage.

[0108] As an optional embodiment of the present invention, such as Figure 1 , Figure 3 As shown, the mass flow controller also includes an outer cover 50, which is fixedly mounted on the seat block 10 and sleeved on the outside 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, such as Figure 1 , Figure 3 , Figure 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 an air source and control the amount of air supplied by the air source to the air chamber 201 through the air supply pipeline 120 and the air supply connector 130. The air source control valve 110 is fixedly mounted on the outer cover 50.

[0110] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled 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 assembly, a cavity assembly, a valve port, and a flow control assembly, among which, The cavity assembly has an air chamber inside, and the cavity assembly has an elastic diaphragm and a valve stem connected to the elastic diaphragm on the side facing the valve port. The valve port has a central inlet and at least one edge outlet, the flow control assembly is connected to the valve stem, and the flow control assembly has a sealing surface for blocking the central inlet; On the side of the cavity assembly furthest from the valve port, the air supply assembly communicates with the air cavity and is used to regulate the gas pressure in the air cavity to drive the elastic diaphragm to contract or expand, thereby moving the valve stem and the flow control assembly. This causes the sealing surface to move closer to or further away from the central inlet orifice, thus changing the opening of the flow control valve and altering the flow rate of fluid flowing from the central inlet orifice to the edge outlet orifice. The flow control assembly includes a valve block and an elastic element. One end of the valve stem is fixedly connected to the elastic diaphragm, and the other end of the valve stem can pass through the central inlet hole. The valve block is fixedly mounted on the valve stem, and the sealing surface is located on the valve block. The elastic element is used to drive the valve block to move toward the air chamber by elastic force so that the sealing surface completely seals the central inlet 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. The flow control plate is disposed 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. The side of the flow control plate facing the sealing surface also has an annular protrusion surrounding the central inlet hole. The sealing surface is used to contact the annular protrusion to block the central inlet hole.

3. The flow control valve according to claim 2, characterized in that, The valve block includes a valve block body and a sealing ring. The valve block body has a first annular groove on the side facing the annular protrusion. The sealing ring is disposed in the first annular groove, and the sealing surface is located on the sealing ring.

4. The flow control valve according to claim 2, characterized in that, The valve block is located on the side of the flow control plate away from the air chamber. A second annular groove is formed on the side of the valve block away from the air chamber. The elastic element is a spring, and one end of the elastic element is correspondingly disposed in the second annular groove.

5. The flow control valve according to claim 2, characterized in that, The valve block is located on the side of the flow control plate facing the air chamber, and a second annular groove is formed on the side of the valve block away from the air chamber. The elastic element is a spring, which is sleeved on the valve stem, and one end of the elastic element is correspondingly disposed in the second annular groove.

6. The flow control valve according to claim 2, characterized in that, The valve block is located on the side of the flow control plate facing the air chamber. The flow control assembly also includes a transmission block, which is fixedly mounted on the valve stem and located on the side of the flow control plate away from the air chamber. A third annular groove is formed on the side of the transmission block away from the flow control plate. The elastic element is a spring, and one end of the elastic element is correspondingly disposed in the third annular groove.

7. The flow control valve according to any one of claims 1 to 6, characterized in that, The cavity assembly includes a cavity and a deformable element. A receiving groove is formed at the bottom of the cavity, and an air groove is formed at the bottom of the receiving groove. The deformable element includes a mounting cylinder, the elastic diaphragm, and the valve stem. The mounting cylinder is sealed in the receiving groove so that the deformable element seals the air groove to form the air cavity.

8. The flow control valve according to claim 7, characterized in that, The mounting cylinder, the elastic diaphragm, and the valve stem are formed as an integral structure.

9. The flow control valve according to claim 7, characterized in that, The thickness of the elastic diaphragm is 0.3mm-0.6mm.

10. The flow control valve according to any one of claims 1 to 6, characterized in that, The cavity assembly is equipped with a pressure feedback sensor, which is used to detect the gas pressure in the gas cavity.

11. A mass flow controller, characterized in that, The device includes a seat block, a flow detection device, a control device, and a flow control valve as described in any one of claims 1 to 10. A fluid passage is formed in the seat block, the flow detection device is used to detect the fluid flow rate in the fluid passage, the flow control valve is connected to the fluid passage, and the control device is used to control the opening degree of the flow control valve according to the fluid flow rate detected by the flow detection device, so that the fluid flow rate reaches a set flow rate value.

12. The mass flow controller according to claim 11, characterized in that, The mass flow controller also includes an outer cover, which is fixedly mounted on the base block and sleeved on the outside of the control device, the flow detection device, and the flow control valve; The gas supply assembly includes a gas source control valve, a gas supply pipeline, and a gas supply connector. The gas supply pipeline is connected between the gas supply connector and the gas source control valve. The gas source control valve is used to connect to a gas source and control the amount of gas supplied by the gas source to the gas chamber through the gas supply pipeline and the gas supply connector. The gas source control valve is fixedly mounted on the outer cover.

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