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 a valve port, a valve core and a piezoelectric ceramic driver, the valve port is provided with a central outflow hole and at least one edge inflow hole, and one end, deviating from the valve core, of the edge inflow hole and one end, deviating from the valve core, of the central outflow hole are respectively used for leading in and leading out fluid; the valve element is provided with a sealing face, the sealing face can block the end, facing the valve element, of the central outflow hole, the piezoelectric ceramic driver is used for driving the valve element to elastically deform, the sealing face is made to be close to the valve port and block the central outflow hole, and when the valve element recovers to be in a natural state, a normally-open gap exists between the sealing face and the valve port. According to the mass flow controller, the piezoelectric ceramic driver is adopted as a part for driving the valve element, and a coil is not arranged in the piezoelectric ceramic driver, so that the situation that the control precision of the mass flow controller is affected due to heating in long-time use is avoided, and the stability of the mass flow controller is improved.

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 mass flow controllers in the prior art can currently realize the function of normally open or normally closed valves. The solenoid valve part mainly consists of a coil and a valve body, and the opening and closing of the valve are controlled by a circuit board. However, the normally open valve type gas mass flow controllers in the prior art have the disadvantages of complex structure, great processing difficulty, and unstable performance.

[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 improve the stability of the mass flow controller.

[0006] To achieve the above-mentioned purpose, as one aspect of the present invention, a flow control valve is provided, which includes a valve port, a valve core and a piezoelectric ceramic driver, the valve port having a central outlet hole and at least one edge inlet hole, the edge inlet hole facing away from the valve core and the central outlet hole facing away from the valve core are respectively used to introduce and lead out fluid, the valve core has a sealing surface, and the sealing surface can block the end of the central outlet hole facing the valve core, the piezoelectric ceramic driver is used to drive the valve core to undergo elastic deformation, so that the sealing surface approaches the valve port and blocks the central outlet hole, and when the valve core restores its shape to a natural state, there is a normally open gap between the sealing surface and the valve port.

[0007] Optionally, the valve core includes a mounting tube, a blocking block and an elastic diaphragm, the blocking block is arranged in the mounting tube, and the sealing surface is formed on the blocking block, the elastic diaphragm is connected between the side walls around the blocking block and the inner wall of the mounting tube, and the three are formed as one.

[0008] Optionally, the flow control valve also includes a corrugated gasket, which is arranged around the central outlet hole between the mounting tube and the valve port, and the corrugated gasket is wavy along the circumferential direction to maintain the normally open gap, wherein when the elastic diaphragm is in a natural state, the sealing surface is flush with the end face of the mounting tube facing the valve port.

[0009] Optionally, the elastic diaphragm has a thickness of 0.3 mm-0.6 mm.

[0010] Optionally, a portion of the blocking block located on a side of the elastic diaphragm facing the valve port gradually increases in diameter in a direction toward the valve port.

[0011] Optionally, a limiting conical hole is formed on the top of the blocking block, and the flow control valve also includes a transmission ball, which is correspondingly arranged in the limiting conical hole, and the piezoelectric ceramic driver is used to push the transmission ball away from the side of the valve port to drive the blocking block to move.

[0012] Optionally, the flow control valve further comprises a cushion block and a pair of butterfly springs, the blocking block comprises a transmission part and a blocking part, the transmission part is located on a side of the blocking part away from the valve port, the blocking part is connected to the elastic diaphragm, and the limiting cone hole is formed on a side of the transmission part away from the valve port;

[0013] A gasket installation groove is formed on the inner wall of the installation cylinder away from the valve port, the gasket is fixedly arranged in the gasket installation groove, an avoidance hole is formed in the gasket, one end of the transmission part away from the valve port passes through the avoidance hole, and the openings of the two butterfly springs are opposite to each other and stacked between the piezoelectric ceramic driver and the gasket.

[0014] Optionally, the flow control valve also includes a valve seat, and a driver mounting groove and a barrel mounting groove are respectively formed on opposite sides of the valve seat, the driver mounting groove and the barrel mounting groove are connected by a connecting hole, the mounting barrel is accommodated in the barrel mounting groove, and the end of the piezoelectric ceramic driver away from the valve core is fixed, and the end of the transmission part away from the valve port can pass through the avoidance hole and enter the connecting hole.

[0015] Optionally, a spring receiving groove is formed on the top of the cushion block, and the butterfly spring is arranged between the piezoelectric ceramic driver and the bottom surface of the spring receiving groove.

[0016] Optionally, the central outlet hole includes a first straight section, a tapered section, and a second straight section connected in sequence along a direction away from the valve core, the diameter of the first straight section is greater than the diameter of the second straight section, and the diameters at both ends of the tapered section correspond to the diameters of the first straight section and the second straight section, respectively.

[0017] Optionally, the flow control valve also includes a first sealing ring, a sealing receiving groove is formed on the surface of the valve port facing away from the valve core, the end of the central outlet hole facing away from the valve core is connected to the sealing receiving groove, and the first sealing ring is arranged in the sealing receiving groove.

[0018] 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 a flow control valve provided by the present invention, 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.

[0019] Optionally, the seat block includes a seat block body, an air inlet connector and an air outlet connector, the fluid passage is formed in the seat block body, the air inlet connector is connected to the inlet end of the fluid passage, and the air outlet connector is connected to the outlet end of the fluid passage.

[0020] Optionally, the flow detection device includes a diverter, a baffle ring and a flow sensor, the diverter and the baffle ring are arranged in the fluid passage in sequence along the fluid flow direction, the diverter is used to divert part of the fluid to the flow sensor, the flow sensor is used to detect the fluid flow passing through itself to determine the fluid flow in the fluid passage, and the outlet end of the flow sensor is connected to the outlet end of the baffle ring.

[0021] Optionally, the fluid passage includes an upstream passage and a downstream passage, a valve mounting groove is formed on the seat block body, the upstream passage and the downstream passage are respectively connected to the bottom of the valve mounting groove to form an edge outlet and a central inlet, the valve port is arranged in the valve mounting groove, and the central outlet hole is connected to the central inlet, the edge inlet hole is connected to the edge outlet, and the valve seat is fixedly connected to the seat block body.

[0022] Optionally, the mass flow controller also includes a second sealing ring, the mounting tube is inserted into the valve mounting groove at one end facing the valve port, a first annular sealing groove is formed on the side wall of the mounting tube facing the valve port, a second annular sealing groove surrounding the valve mounting groove and connected to the valve mounting groove is formed on the seat block body, and the second sealing ring is arranged in the space defined by the first annular sealing groove and the second annular sealing groove to seal the gap between the mounting tube and the valve mounting groove.

[0023] In the flow control valve and mass flow controller provided by the present invention, the sealing surface of the valve core can be driven by a piezoelectric ceramic driver to approach the valve port or be restored to a state of maintaining a normally open gap with the valve port under the action of the elastic force of the valve core. By changing the opening of the valve port, the flow rate of the fluid in the edge inlet hole flowing into the central outlet hole through the space between the valve port and the valve core is changed. The component for driving the valve core in the present invention adopts a piezoelectric ceramic driver. Compared with the electromagnet structure in the prior art, the piezoelectric ceramic driver does not have a coil, so it will not generate heat during long-term use and affect its own control accuracy, thereby improving the stability of the mass flow controller.

[0024] Furthermore, the component driving the valve core in the present invention adopts a piezoelectric ceramic driver, so there is no need to set up a welded part such as a valve body with magnetic conductivity, thereby ensuring the sealing performance of the mass flow controller, thereby reducing the production and testing costs of the mass flow controller while ensuring the stability of the mass flow controller. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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:

[0026] Figure 1 is a schematic structural diagram of a flow control valve provided by an embodiment of the present invention;

[0027] Figure 2 yes Figure 1 A partial enlarged schematic diagram of the medium flow control valve in area A;

[0028] Figure 3 Schematic diagram of the structure of a valve port in a flow control valve provided by an embodiment of the present invention;

[0029] Figure 4 yes Figure 3 A schematic diagram of the structure of the middle valve port viewed from above;

[0030] Figure 5 is a schematic structural diagram of a first sealing ring in a flow control valve provided in an embodiment of the present invention;

[0031] Figure 6 Schematic diagram of the structure of a valve core in a flow control valve provided by an embodiment of the present invention;

[0032] Figure 7 It is a structural schematic diagram of a cushion block in a flow control valve provided by an embodiment of the present invention;

[0033] Schematic diagram of the steps;

[0034] Figure 8 Schematic diagram of the structure of a butterfly spring in a flow control valve provided by an embodiment of the present invention;

[0035] Fig. 9 Schematic diagram of the structure of a corrugated gasket in a flow control valve provided by an embodiment of the present invention;

[0036] Fig.10 yes Fig. 9 Schematic diagram of the top view of the corrugated gasket.

[0037] Description of reference numerals:

[0038] 100: Valve port

[0039] 110: Central outflow hole

[0040] 111: First straight section

[0041] 112: Narrowing section

[0042] 113: Second straight section

[0043] 114: Sealed receiving groove

[0044] 120: Edge inlet hole

[0045] 121: First annular connecting groove

[0046] 122: Second annular connecting groove

[0047] 200: Valve core

[0048] 210: Install the barrel

[0049] 211: Pad installation slot

[0050] 212: First annular sealing groove

[0051] 220: Blocking block

[0052] 221: Transmission

[0053] 222: Blocking Department

[0054] 223: Limiting cone hole

[0055] 230: Elastic diaphragm

[0056] 300: Piezoelectric drive components

[0057] 310: Piezoelectric Ceramic Driver

[0058] 320: Sleeve

[0059] 330: Lock nut

[0060] 340: Transmission Ball

[0061] 350: butterfly spring

[0062] 360: Pad

[0063] 361: Spring receiving groove

[0064] 362: Avoidance hole

[0065] 400: Valve seat

[0066] 500: Corrugated gasket

[0067] 610: First sealing ring

[0068] 620: Second sealing ring

[0069] 30: Flow control valve

[0070] 10: Seat block

[0071] 11: Seat block body

[0072] 12: Air intake connector

[0073] 13: Air outlet connector

[0074] 101: Upstream Pathway

[0075] 102: Downstream pathway

[0076] 20: Flow detection device

[0077] 21: Shunt

[0078] 22: Flow sensor

[0079] 23: retaining ring

[0080] 30: Flow control valve

[0081] 40: Control device

[0082] 50: Outer cover DETAILED DESCRIPTION

[0083] 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.

[0084] The inventors of the present invention have discovered during research that solenoid valves are often used as valve structures for controlling flow rates in existing mass flow controllers, and the magnetic force generated by the magnetic seat in the solenoid valve is generated when the valve body assembly and the coil generate electromagnetic force and act together on the magnetic seat after the controller is energized. Therefore, during long-term stable operation of the gas mass flow controller, the coil will inevitably generate heat, thereby increasing the resistance value of the coil, while the voltage provided by the controller is constant, which will cause the current to decrease, negatively affecting the opening and closing actions of the solenoid valve, affecting the valve opening efficiency, and further causing the accuracy of the mass flow controller to change, affecting the stability of the mass flow controller.

[0085] In order to solve the above technical problems, as one aspect of the present invention, a flow control valve 30 is provided, such as Figure 1 , Figure 2 As shown, the flow control valve 30 includes a valve port 100, a valve core 200 and a piezoelectric drive assembly 300, and the piezoelectric drive assembly 300 includes a piezoelectric ceramic driver 310, as shown in FIG. Figure 3 As shown, the valve port 100 has a central outlet hole 110 and at least one edge inlet hole 120, the end of the edge inlet hole 120 away from the valve core 200 and the end of the central outlet hole 110 away from the valve core 200 are respectively used to introduce and lead out fluid, the valve core 200 has a sealing surface, and the sealing surface can block the end of the central outlet hole 110 facing the valve core 200, the piezoelectric ceramic driver 310 is used to drive the valve core 200 to undergo elastic deformation, so that the sealing surface approaches the valve port 100 and blocks the central outlet hole 110, when the valve core 200 restores its shape to a natural state (i.e., the piezoelectric ceramic driver 310 is not powered on), the sealing surface is away from the valve port 100, and there is a normally open gap between the sealing surface and the valve port 100.

[0086] The flow control valve 30 provided by the present invention is a normally open valve. In the flow control valve 30 provided by the present invention, the sealing surface of the valve core 200 can be driven by the piezoelectric ceramic driver 310 to approach the valve port 100 or be restored to a state of maintaining a normally open gap with the valve port 100 under the action of the elastic force of the valve core 200. By changing the opening 100 of the valve port, the flow rate of the fluid in the edge inlet hole 120 flowing into the central outlet hole 110 through the space between the valve port 100 and the valve core 200 is changed. In the present invention, the component for driving the valve core 200 adopts a piezoelectric ceramic driver 310. Compared with the electromagnet structure in the prior art, the piezoelectric ceramic driver 310 is not provided with a coil, so that it will not generate heat during long-term use and affect its own control accuracy, thereby improving the stability of the mass flow controller.

[0087] Moreover, in the existing mass flow controllers using electromagnetic valve structures, the valve body assembly is often not a single part, but is welded from three parts. For the assembly of the whole machine, the valve body needs to be vacuum leak-tested before use to ensure the welding sealing, thus increasing the manufacturing process and the inspection process, wasting manpower and financial resources. However, the component driving the valve core 200 in the present invention adopts a piezoelectric ceramic driver 310, so there is no need to set up a welded part of the valve body assembly with magnetic conductivity, thereby ensuring the sealing performance of the mass flow controller, thereby reducing the production and inspection costs of the mass flow controller while ensuring the stability of the mass flow controller.

[0088] In the existing mass flow controller, the valve core assembly is not a single part, but is welded by a core body and a spring sheet. The spring sheet is sleeved on the step of the core body and fixed by welding. The welding points require high process precision and uniformity, and the welding is difficult. In addition, during the long-term stability test of multi-point welding, once the welding points become loose, the mass flow controller may malfunction, causing huge losses to the operation of the equipment.

[0089] To solve this technical problem, as a preferred implementation of the present invention, Figure 2 As shown, the valve core 200 includes a mounting tube 210, a blocking block 220 and an elastic diaphragm 230. The blocking block 220 is arranged in the mounting tube 210, and a sealing surface is formed on the blocking block 220. The elastic diaphragm 230 is connected between the side walls around the blocking block 220 and the inner wall of the mounting tube 210, and the three are formed as a whole.

[0090] In the embodiment of the present invention, the mounting cylinder 210 and the blocking block 220 are elastically connected via the elastic diaphragm 230, and the three are formed into one body, thereby avoiding the airtightness problem caused by welding and further ensuring the airtightness of the mass flow controller.

[0091] Optionally, the sealing surface at the bottom of the blocking block 220 is higher than the end surface at the bottom of the mounting tube 210 , so that the mounting tube 210 is directly in contact with the valve port 100 and positioned, thereby leaving a normally open gap between the sealing surface and the valve port 100 .

[0092] More preferably, if Figure 2 , Fig. 9 , Fig.10 As shown, the flow control valve 30 also includes a corrugated gasket 500, which is arranged around the central outlet hole 110 between the mounting cylinder 210 and the valve port 100, and the corrugated gasket 500 is wavy along the circumferential direction to maintain a normally open gap, wherein, when the elastic diaphragm 230 is in a natural state (i.e., when the piezoelectric ceramic driver 310 is not powered), the sealing surface is flush with the end face of the mounting cylinder 210 facing the valve port 100.

[0093] In the embodiment of the present invention, a corrugated gasket 500 is arranged between the mounting cylinder 210 and the valve port 100. The corrugated gasket 500 is wavy in the circumferential direction, so as to maintain the normally open gap between the mounting cylinder 210 and the valve port 100 while allowing the gas to pass freely, so that the sealing surface flush with the end surface of the mounting cylinder 210 is fixedly spaced from the valve port 100 when the piezoelectric ceramic driver 310 is not powered, thereby realizing the normally open function. At the same time, when the elastic diaphragm 230 is in the natural state, the sealing surface is coplanar with the end surface of the mounting cylinder 210, which is conducive to ensuring the accuracy of the relative position between the sealing surface and the end surface of the mounting cylinder 210 during the processing stage, thereby ensuring the flow control accuracy of the flow control valve.

[0094] As an optional embodiment of the present invention, the thickness of the elastic diaphragm 230 is 0.3 mm-0.6 mm.

[0095] As an optional embodiment of the present invention, the thickness of the corrugated gasket 500 is 0.15mm-0.8mm.

[0096] As a preferred embodiment of the present invention, Figure 2 , Figure 6 As shown, the diameter of the portion of the blocking block 220 located on the side of the elastic diaphragm 230 facing the valve port 100 gradually increases along the direction toward the valve port 100 .

[0097] In the embodiment of the present invention, the portion of the blocking block 220 located on the side of the elastic diaphragm 230 facing the valve port 100 gradually increases in diameter along the direction toward the valve port 100, thereby increasing the area of ​​the sealing surface while ensuring the radial dimension of the elastic diaphragm 230, thereby ensuring the air tightness of the flow control valve 30.

[0098] As an optional embodiment of the present invention, the angle between the side wall of the blocking block 220 located on the side of the elastic diaphragm 230 facing the valve port 100 and the sealing surface is 45°-60°.

[0099] As a preferred embodiment of the present invention, Figure 2 , Figure 6 As shown, a limiting conical hole 223 is formed on the top of the blocking block 220, and the flow control valve 30 also includes a transmission ball 340, which is correspondingly arranged in the limiting conical hole 223. The piezoelectric ceramic driver 310 is used to push the transmission ball 340 away from the side of the valve port 100 to drive the blocking block 220 to move.

[0100] In the embodiment of the present invention, the piezoelectric ceramic driver 310 indirectly drives the blocking block 220 to move by pushing the transmission ball 340, thereby utilizing the spherical surface of the transmission ball 340 to ensure the accuracy of the direction in which the piezoelectric ceramic driver 310 transmits the thrust to the blocking block 220, thereby ensuring the control accuracy of the mass flow controller.

[0101] As a preferred embodiment of the present invention, Figure 2 , Figure 7 , Figure 8 As shown, the flow control valve 30 further includes a cushion block 360 and a pair of butterfly springs 350, the blocking block 220 includes a transmission part 221 and a blocking part 222, the transmission part 221 is located on the side of the blocking part 222 away from the valve port 100, the blocking part 222 is connected to the elastic diaphragm 230, and the limiting cone hole is formed on the side of the transmission part 221 away from the valve port 100;

[0102] A gasket mounting groove 211 is formed on the inner wall of the mounting cylinder 210 on the side away from the valve port 100, and the gasket 360 is fixedly arranged in the gasket mounting groove 211. An avoidance hole 362 is formed in the gasket 360, and one end of the transmission part 221 away from the valve port 100 passes through the avoidance hole 362. The openings of the two butterfly springs 350 are opposite to each other and stacked between the piezoelectric ceramic driver 310 and the gasket 360.

[0103] In an embodiment of the present invention, the piezoelectric ceramic driver 310 can also elastically contact the pad 360 fixed on the mounting cylinder 210 through the butterfly spring 350, thereby achieving a certain buffering effect through the butterfly spring 350, avoiding the piezoelectric ceramic driver 310 from directly colliding rigidly with the transmission ball 340, thereby extending the service life of the device.

[0104] As an optional embodiment of the present invention, Figure 2 , Figure 7 , Figure 8 As shown, the flow control valve 30 also includes a valve seat 400, and a driver mounting groove and a barrel mounting groove are respectively formed on opposite sides of the valve seat. The driver mounting groove and the barrel mounting groove are connected by a connecting hole. The mounting barrel 210 is accommodated in the barrel mounting groove, and the end of the piezoelectric ceramic driver 310 away from the valve core 200 is fixed, and the end of the transmission part 221 away from the valve port 100 can pass through the avoidance hole 362 and enter the connecting hole.

[0105] As an optional embodiment of the present invention, Figure 1 As shown, the piezoelectric drive assembly 300 also includes a sleeve 320 and a locking nut 330. The piezoelectric ceramic driver 310 is arranged in the sleeve 320. One end of the sleeve 320 is fixedly arranged in the driver mounting groove. The locking nut 330 is fastened to the other end of the sleeve 320 to fix the piezoelectric ceramic driver 310 in the sleeve 320.

[0106] As an optional embodiment of the present invention, Figure 7 As shown, a spring receiving groove 361 is formed on the top of the cushion block 360 , and the butterfly spring 350 is arranged between the piezoelectric ceramic driver 310 and the bottom surface of the spring receiving groove 361 .

[0107] In order to improve the response speed of the flow control valve 30, as a preferred embodiment of the present invention, Figure 3 As shown, the central outlet hole 110 includes a first straight section 111, a tapered section 112 and a second straight section 113 which are connected in sequence along a direction away from the valve core 200. The diameter of the first straight section 111 is greater than the diameter of the second straight section 113, and the diameters at both ends of the tapered section 112 correspond to the diameters of the first straight section 111 and the second straight section 113, respectively.

[0108] In an embodiment of the present invention, the central outlet hole 110 includes a tapered section 112, thereby shortening the path of the gas in the edge inlet hole 120 flowing to the central outlet hole 110, and guiding the surrounding gas to flow into the central outlet hole 110 over a larger area, thereby saving gas passage time, shortening the response time of the flow control valve 30, and thereby improving the response speed of the mass flow controller.

[0109] In order to further improve the air tightness of the flow control valve 30, as a preferred embodiment of the present invention, Figure 2 As shown, the flow control valve 30 also includes a first sealing ring 610, and a sealing receiving groove 114 is formed on the surface of the valve port 100 facing away from the valve core 200, and the end of the central outlet hole 110 facing away from the valve core 200 is connected to the sealing receiving groove 114, and the first sealing ring 610 is arranged in the sealing receiving groove 114.

[0110] As an optional implementation of the present invention, the first sealing ring 610 is an O-ring.

[0111] As an optional implementation of the present invention, the material of the first sealing ring 610 includes polytetrafluoroethylene (PTFE) or polytrifluorochloroethylene (PCTFE).

[0112] As an optional embodiment of the present invention, Figure 3 As shown, a plurality of edge inlet holes 120 are formed in the valve port 100, a first annular connecting groove 121 is formed on the side of the valve port 100 away from the valve core 200, a second annular connecting groove 122 is formed on the side of the valve port 100 facing the valve core 200, and both ends of the plurality of edge inlet holes 120 are connected to each other through the first annular connecting groove 121 and the second annular connecting groove 122 respectively.

[0113] As a second aspect of the present invention, a gas measurement and control device is provided, including a seat block 10, a flow detection device 20, a control device 40 and a flow control valve 30 provided by the present invention, 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, and 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.

[0114] In the mass flow controller provided by the present invention, the sealing surface of the valve core 200 can be driven by the piezoelectric ceramic driver 310 to approach the valve port 100 or be restored to a state of maintaining a normally open gap with the valve port 100 under the action of the elastic force of the valve core 200. By changing the opening of the valve port, the flow rate of the fluid in the edge inlet hole 120 flowing into the central outlet hole 110 through the space between the valve port 100 and the valve core 200 is changed. The component for driving the valve core 200 in the present invention adopts a piezoelectric ceramic driver 310. Compared with the electromagnet structure in the prior art, the piezoelectric ceramic driver 310 does not have a coil, so that it will not generate heat during long-term use and affect its own control accuracy, thereby improving the stability of the mass flow controller.

[0115] Furthermore, the component driving the valve core 200 in the present invention adopts a piezoelectric ceramic driver 310, so there is no need to set up a welded part such as a valve body with magnetic conductivity, thereby ensuring the sealing performance of the mass flow controller, thereby reducing the production and testing costs of the mass flow controller while ensuring the stability of the mass flow controller.

[0116] As an optional embodiment of the present invention, Figure 1 As 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.

[0117] As an optional embodiment of the present invention, Figure 1 As shown, the flow detection device 20 includes a diverter 21, a baffle ring 23 and a flow sensor 22. The diverter 21 and the baffle ring 23 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. The outflow end of the flow sensor 22 is connected to the outflow end of the baffle ring 23.

[0118] As an optional embodiment of the present invention, the fluid passage includes an upstream passage 101 and a downstream passage 102, and a valve mounting groove is formed on the seat block body 11. The upstream passage 101 and the downstream passage 102 are respectively connected to the bottom of the valve mounting groove to form an edge outlet and a central inlet. The valve port 100 is arranged in the valve mounting groove, and the central outlet hole 110 is connected to the central inlet, and the edge inlet hole 120 is connected to the edge outlet, and the valve seat 400 is fixedly connected to the seat block body 11.

[0119] As an optional embodiment of the present invention, Figure 2 As shown, the mass flow controller also includes a second sealing ring 620, and the end of the mounting cylinder 210 facing the valve port 100 is inserted into the valve mounting groove, and a first annular sealing groove 212 is formed on the side wall of the mounting cylinder 210 facing the valve port 100, and a second annular sealing groove surrounding the valve mounting groove and connected to the valve mounting groove is formed on the seat block body 11, and the second sealing ring 620 is arranged in the space defined by the first annular sealing groove 212 and the second annular sealing groove to seal the gap between the mounting cylinder 210 and the valve mounting groove.

[0120] As an optional implementation of the present invention, the second sealing ring 620 is an O-ring.

[0121] As an optional embodiment of the present invention, Figure 1 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 sensor 22 and the flow control valve 30 .

[0122] 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: The flow control valve includes a valve port, a valve core and a piezoelectric ceramic driver. The valve port has a central outflow hole and at least one edge inflow hole. The end of the edge inflow hole away from the valve core and the end of the central outflow hole away from the valve core are respectively used to introduce and lead out fluid. The valve core has a sealing surface, and the sealing surface can block the end of the central outflow hole toward the valve core. The piezoelectric ceramic driver is used to drive the valve core to undergo elastic deformation so that the sealing surface approaches the valve port and blocks the central outflow hole. When the valve core restores its shape to a natural state, there is a normally open gap between the sealing surface and the valve port.

2. The flow control valve according to claim 1, characterized in that: The valve core includes a mounting tube, a blocking block and an elastic diaphragm. The blocking block is arranged in the mounting tube, and the sealing surface is formed on the blocking block. The elastic diaphragm is connected between the side walls around the blocking block and the inner wall of the mounting tube, and the three are formed into one.

3. The flow control valve according to claim 2, characterized in that: The flow control valve also includes a corrugated gasket, which is arranged around the central outlet hole between the mounting tube and the valve port, and the corrugated gasket is wavy along the circumferential direction to maintain the normally open gap, wherein when the elastic diaphragm is in a natural state, the sealing surface is flush with the end surface of the mounting tube facing the valve port.

4. The flow control valve according to claim 2, characterized in that: The thickness of the elastic diaphragm is 0.3mm-0.6mm.

5. The flow control valve according to claim 2, characterized in that: The diameter of a portion of the blocking block located on a side of the elastic diaphragm facing the valve port gradually increases in a direction toward the valve port.

6. The flow control valve according to claim 2, characterized in that: A limiting conical hole is formed on the top of the blocking block, and the flow control valve also includes a transmission ball, which is correspondingly arranged in the limiting conical hole. The piezoelectric ceramic driver is used to push the transmission ball away from one side of the valve port to drive the blocking block to move.

7. The flow control valve according to claim 6, characterized in that: The flow control valve further comprises a cushion block and a pair of butterfly springs, the blocking block comprises a transmission part and a blocking part, the transmission part is located on a side of the blocking part away from the valve port, the blocking part is connected to the elastic diaphragm, and the limiting cone hole is formed on a side of the transmission part away from the valve port; A gasket installation groove is formed on the inner wall of the installation cylinder away from the valve port, the gasket is fixedly arranged in the gasket installation groove, an avoidance hole is formed in the gasket, one end of the transmission part away from the valve port passes through the avoidance hole, and the openings of the two butterfly springs are opposite to each other and stacked between the piezoelectric ceramic driver and the gasket.

8. The flow control valve according to claim 7, characterized in that: The flow control valve also includes a valve seat, and a driver mounting groove and a barrel mounting groove are respectively formed on opposite sides of the valve seat. The driver mounting groove and the barrel mounting groove are connected by a connecting hole, and the mounting barrel is accommodated in the barrel mounting groove. The end of the piezoelectric ceramic driver away from the valve core is fixedly arranged, and the end of the transmission part away from the valve port can pass through the avoidance hole and enter the connecting hole.

9. The flow control valve according to claim 7, characterized in that: A spring receiving groove is formed on the top of the cushion block, and the butterfly spring is arranged between the piezoelectric ceramic driver and the bottom surface of the spring receiving groove.

10. The flow control valve according to any one of claims 1 to 9, characterized in that: The central outflow hole includes a first straight section, a tapered section, and a second straight section connected in sequence along a direction away from the valve core. The diameter of the first straight section is greater than the diameter of the second straight section. The diameters at both ends of the tapered section correspond to the diameters of the first straight section and the second straight section, respectively.

11. 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 10, 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.

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