Pneumatic constant-pressure diaphragm valve for conveying chemical liquid medicine in semiconductor manufacturing

Abstract

The invention relates to a pneumatic constant-pressure diaphragm valve for chemical liquid conveying in semiconductor manufacturing. The pneumatic constant-pressure diaphragm valve sequentially comprises a mechanism body and a mounting bottom plate from top to bottom. An inlet end runner and an outlet end runner are sequentially arranged on the mechanism main body from left to right, an outlet end waist groove communicated with the outlet end runner is formed in the right side of the top of the upper second-stage step, and an inlet end waist groove communicated with the inlet end runner is formed in the left side of the bottom of the lower second-stage step; the device further comprises an executing mechanism assembly and a sealing assembly. The pressure of the input fluid can be dynamically adjusted, so that the pressure of the output fluid is stably output, and the influence of pressure fluctuation of the external input fluid on the pressure of the output fluid of the valve is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field related to chemical liquid valves, and in particular to a pneumatic constant-pressure diaphragm valve for conveying chemical liquid in semiconductor manufacturing. Background Art

[0002] At present, most of the constant pressure valves are used in the field of gas media, among which more are used as pressure reducing valves, and some are used as exhaust safety valves. The structure of these valves can be unified as follows: when the inlet pressure is less than the valve core opening pressure, the fluid flows out normally, and when the inlet pressure is greater than the valve core opening pressure, the valve core opens and the fluid flows out. In fact, this constant pressure valve, gas pressure stabilizing valve, does not stabilize the pressure of the inflowing fluid and output the fluid pressure stably. Moreover, the current structural design of the constant pressure valve is mostly only suitable for gas media, not for fluid media, especially liquids with a high viscosity coefficient.

[0003] After a massive search, it was found that the Chinese patent announcement number is CN106352124B, which discloses a constant pressure valve, providing a constant pressure valve that switches intake, cuts off air and reverse exhaust according to the size of the intake pressure. It has the following structures: a main pressure regulating seat, a valve body, a valve seat, a main valve core, an auxiliary valve core, a main pressure regulating shaft, a main pressure regulating cap, a main pressure regulating spring, an auxiliary pressure regulating spring, an auxiliary valve cover body, an auxiliary valve body, a diaphragm and other parts that are sealed and connected. There are a front port and a rear port on the valve body. Its main working principle is that when the pressure at the front port is greater than the opening pressure of the main valve core, the air flow flows from the front port to the rear port to achieve air intake. When the pressure at the front port decreases the opening pressure, the air flow flows from the rear port to the front port to achieve reverse exhaust. When the pressure at the front port is between the opening pressures of the main valve core and the auxiliary valve core, the gas path back cut-off is achieved. In the relevant patents, because the spring assembly is assembled in the valve cavity, the reciprocating motion of the spring and the friction surface between the spring and the valve body have the risk of particle shedding; secondly, the spring assembly is completely exposed to the fluid medium and has the risk of being corroded by the fluid medium. This working condition does not meet the cleanliness requirements in the semiconductor field. At the same time, in this patent, the flow direction of the gas medium is judged by the difference between the inlet pressure and the valve seat closing force, which does not achieve the effect of stabilizing the pressure of the fluid medium, so it is not suitable for the working condition of fluid medium pressure stabilization.

[0004] After a massive search, it was found that the Chinese patent announcement number is CN115962326A, which discloses a constant pressure valve, providing a constant pressure valve that adjusts the valve opening pressure according to needs and improves the accuracy of the constant pressure valve. It provides a constant pressure valve with a piston-like structure. This constant pressure valve determines the flow direction of the medium by the relationship between the fluid medium and the valve core opening pressure. Secondly, by adjusting the spring pressure, the valve core opening pressure is controlled to achieve the adjustment of the valve opening pressure. In the related art, the adjusting screw belongs to the external drive component, and the valve core opening is adjusted by adjusting the spring pressure. This operation is "external drive". This structure is an inherent thinking in the field of constant pressure valves, and this method cannot accurately adjust the pressure. Thirdly, the valve structure in the related art, if the pressure flowing into the inlet is limited, the structural design of this constant pressure valve cannot achieve the discharge of the medium. At the same time, the connection between the conical plug and the sliding plate is completely supported by the supporting spring. The axial movement direction of the spring cannot be guaranteed to be a linear motion, and this spring is in a horizontal state, and it cannot be guaranteed that the movement of this spring is a linear reciprocating linear motion. Therefore, the sealing condition of this valve needs to be studied.

[0005] After massive searches, it was found that the Chinese patent announcement number is CN203823224U, which discloses a gas pressure-stabilizing valve that reduces the vibration and noise of the pressure-stabilizing valve and extends the service life of the pressure-stabilizing valve. In the related technology, the "external drive" form is used to adjust the spring pressure to stabilize the medium pressure. Therefore, this structure cannot adjust the pressure in real time. At the same time, in order to reduce wear, this structure is designed with PEEK plastic between the valve stem and the valve body. Because PEEK plastic will be affected by strong oxidizing acids (concentrated sulfuric acid), this solution cannot be applied in the field of semiconductor valves.

[0006] In summary, the existing constant pressure valves have the following main problems:

[0007] 1. The flow channel structure of the valve is only suitable for gas media, not for liquid media, especially fluids with a large viscosity coefficient.

[0008] 2. The main function of most constant pressure valves is to relieve pressure and exhaust gas, and they cannot dynamically balance the fluid pressure.

[0009] 3. Currently, most constant pressure valves use "external drive" as a pressure regulation method.

[0010] 4. The structures of most current constant pressure valves do not meet the cleanliness requirements of the semiconductor field and are not suitable for the semiconductor field.

[0011] In view of the above-mentioned defects, the designer actively carried out research and innovation in order to create a pneumatic constant-pressure diaphragm valve for chemical liquid transportation in semiconductor manufacturing, so as to make it more valuable for industrial use. Summary of the invention

[0012] In order to solve any of the above technical problems, the purpose of the present invention is to provide a pneumatic constant pressure diaphragm valve for chemical liquid transportation in semiconductor manufacturing.

[0013] To achieve the above object, the present invention adopts the following technical solution:

[0014] A pneumatic constant pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing, which comprises a mechanism body and a mounting base plate from top to bottom;

[0015] An inlet end flow channel and an outlet end flow channel are sequentially arranged on the main body of the mechanism from left to right, an upper first step and an upper second step are sequentially arranged on the inner side of the top of the main body of the mechanism from outside to inside, a lower first step and a lower second step are sequentially arranged on the inner side of the bottom of the main body of the mechanism from outside to inside, a central through hole is opened in the middle of the inner side of the upper second step, an outlet end waist groove connected to the outlet end flow channel is opened on the right side of the top of the upper second step, and an inlet end waist groove connected to the inlet end flow channel is opened on the left side of the bottom of the lower second step;

[0016] Also included are an actuator assembly and a seal assembly;

[0017] The actuator assembly includes an actuator top portion and an actuator bottom portion from top to bottom, the actuator top portion is mounted on the top of the actuator body, the actuator bottom portion is mounted on the bottom of the actuator body, the mounting base plate is mounted on the bottom of the actuator bottom portion, an actuator shaft is mounted in the actuator bottom portion, and an air inlet hole is opened at the top of the actuator top portion;

[0018] The sealing assembly includes an upper diaphragm, a diaphragm connecting column and a lower double-headed diaphragm from top to bottom. The diaphragm connecting column is located in the central through hole. The upper diaphragm installed on the top of the diaphragm connecting column is located between the top end of the actuator and the main body of the mechanism. The lower double-headed diaphragm installed at the bottom of the diaphragm connecting column is connected to the actuator shaft below.

[0019] As a further improvement of the present invention, it also includes a spring assembly located at the inner side of the bottom of the bottom end of the actuator, and the actuator shaft is in contact with the spring assembly below.

[0020] As a further improvement of the present invention, the spring assembly includes an inner spring and an outer spring from the inside to the outside, the working stroke of the inner spring is greater than the working stroke of the outer spring, and the spring stiffness of the outer spring is greater than the spring stiffness of the inner spring.

[0021] As a further improvement of the present invention, the top end of the actuator, the actuator body, the bottom end of the actuator and the mounting base plate are connected together by a plurality of bolts.

[0022] As a further improvement of the present invention, the head of the bolt is located in the first mounting hole in the top end of the actuator, and an open gasket and a flat gasket are installed in sequence from top to bottom between the bottom of the bolt head and the first mounting hole, and the tail of the bolt is installed in the second mounting hole in the mounting base plate through a nut.

[0023] As a further improvement of the present invention, rubber plugs are installed on the outer sides of the first mounting hole and the second mounting hole.

[0024] As a further improvement of the present invention, a positioning groove is provided on the top outer side of the mechanism body, a positioning block matching the above-mentioned positioning groove is provided on the bottom outer side of the top end portion of the actuator directly above the positioning groove, a sealing groove is provided on the inner side of the positioning block, and an O-ring is installed in the sealing groove.

[0025] As a further improvement of the present invention, sealing ribs are provided at the inner middle portion of the upper first step and at the inner middle portion of the lower first step.

[0026] By means of the above scheme, the present invention has at least the following advantages:

[0027] The present invention can dynamically adjust the pressure of the input fluid, so that the output fluid pressure is output stably, and reduce the influence of the external input fluid pressure fluctuation on the valve output fluid pressure.

[0028] The invention can solve the defect of particle precipitation in the traditional constant pressure valve when in use.

[0029] The present invention solves the inaccuracy of the external adjustment mechanism through pneumatic autonomous adjustment.

[0030] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 It is a schematic diagram of the explosion structure of a pneumatic constant pressure diaphragm valve for chemical liquid transportation in semiconductor manufacturing according to the present invention;

[0033] Figure 2 yes Figure 1 A schematic diagram of the internal structure on one side;

[0034] Figure 3 yes Figure 1 Schematic diagram of the internal structure on the other side;

[0035] Figure 4 yes Figure 2 A top view of the main body of the mechanism;

[0036] Figure 5 yes Figure 2 Bottom view of the main body of the mechanism;

[0037] Figure 6 yes Figure 2 A schematic diagram of the partial enlarged structure of the top end of the middle actuator;

[0038] Figure 7 yes Figure 2 Schematic diagram of the partial enlarged structure of the middle sealing component.

[0039] The meanings of the various reference numerals in the figures are as follows.

[0040] Inner spring 1, outer spring 2, rubber plug 3, mounting base plate 4, nut 5, actuator bottom end 6, actuator shaft 7, lower double-headed diaphragm 8, mechanism body 9, O-ring 10, diaphragm connecting column 11, upper diaphragm 12, actuator top end 13, flat gasket 14, open gasket 15, bolt 16;

[0041] Positioning groove 100, upper first step 101, sealing rib 102, lower first step 103, upper second step 104, center through hole 105, lower second step 106, inlet end flow channel 107, inlet end waist groove 108, outlet end waist groove 109, outlet end flow channel 110, positioning block 111, sealing groove 112, air inlet hole 113. DETAILED DESCRIPTION

[0042] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0043] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, rather than all the embodiments. The components of the embodiment of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiment of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiment of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0044] Example

[0045] like Figure 1 to Figure 7 As shown,

[0046] A pneumatic constant-pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing comprises, from top to bottom, a mechanism body 9 and a mounting base plate 4, and also comprises an actuator assembly and a sealing assembly.

[0047] 1. An inlet flow channel 107 and an outlet flow channel 110 are sequentially arranged on the mechanism body 9 from left to right, an upper first step 101 and an upper second step 104 are sequentially arranged on the inner side of the top of the mechanism body 9 from outside to inside, a lower first step 103 and a lower second step 106 are sequentially arranged on the inner side of the bottom of the mechanism body 9 from outside to inside, a central through hole 105 is opened in the middle of the inner side of the upper second step 104, an outlet waist groove 109 connected to the outlet flow channel 110 is opened on the right side of the top of the upper second step 104, and an inlet waist groove 108 connected to the inlet flow channel 107 is opened on the left side of the bottom of the lower second step 106;

[0048] A positioning groove 100 is provided on the outer side of the top of the mechanism body 9 , a positioning block 111 adapted to the positioning groove 100 is provided on the outer side of the bottom of the top end portion 13 of the actuator directly above the positioning groove 100 , a sealing groove 112 is provided on the inner side of the positioning block 111 , and an O-ring 10 is installed in the sealing groove 112 .

[0049] In addition, a sealing rib 102 is provided at the inner middle portion of the upper first step 101 and at the inner middle portion of the lower first step 103 .

[0050] 2. The actuator assembly includes an actuator top portion 13 and an actuator bottom portion 6 from top to bottom. The actuator top portion 13 is installed on the top of the actuator body 9, the actuator bottom portion 6 is installed on the bottom of the actuator body 9, the mounting base plate 4 is installed on the bottom of the actuator bottom portion 6, the actuator shaft 7 is installed in the actuator bottom portion 6, and an air inlet hole 113 is opened at the top of the actuator top portion 13.

[0051] 3. The sealing assembly includes an upper diaphragm 12, a diaphragm connecting column 11 and a lower double-headed diaphragm 8 from top to bottom. The diaphragm connecting column 11 is located in the central through hole 105. The upper diaphragm 12 installed on the top of the diaphragm connecting column 11 is located between the top end 13 of the actuator and the mechanism body 9. The lower double-headed diaphragm 8 installed at the bottom of the diaphragm connecting column 11 is connected to the actuator shaft 7 below.

[0052] 4. It also includes a spring assembly located at the inner side of the bottom of the bottom end 6 of the actuator, and the actuator shaft 7 is in contact with the spring assembly below. The spring assembly includes an inner spring 1 and an outer spring 2 from the inside to the outside, the working stroke of the inner spring 1 is greater than the working stroke of the outer spring 2, and the spring stiffness of the outer spring 2 is greater than the spring stiffness of the inner spring 1.

[0053] 5. The actuator top portion 13, the actuator body 9, the actuator bottom portion 6 and the mounting base plate 4 are connected together by a plurality of bolts 16. The head of the bolt 16 is located in the first mounting hole in the actuator top portion 13, and an open gasket 15 and a flat gasket 14 are installed in sequence from top to bottom between the lower portion of the bolt 16 head and the first mounting hole, and the tail of the bolt 16 is installed in the second mounting hole in the mounting base plate 4 through a nut 5. Rubber plugs 3 are installed on the outside of the first mounting hole and the second mounting hole.

[0054] The first embodiment of the present invention:

[0055] Mechanism body 9: has an inlet and an outlet (i.e., an inlet end flow channel 107 and an outlet end flow channel 110). With the inlet on the left and the outlet on the right, a positioning groove 100 is designed on the top of the mechanism body 9 for positioning and installing with the top 13 of the actuator. A two-step step is designed on the top of the mechanism body 9, and a sealing rib 102 is designed in the middle of the upper first step 101. The sealing of the air source power is achieved by forming a sealing structure with the actuator top 13, the upper diaphragm 12 and the mechanism body 9. A two-step step is also designed on the bottom of the mechanism body 9, and a sealing rib 102 is designed in the middle of the lower first step 103. The sealing of the fluid medium is achieved by forming a sealing structure with the actuator bottom 6, the lower double-headed diaphragm 8 and the mechanism body 9. A central through hole 105 is designed in the center of the upper second step 104, and the through hole is connected up and down. At the same time, an inlet end waist groove 108 is designed between the inlet end flow channel 107 and the central through hole 105, and the opening end of the inlet end waist groove 108 is on the lower second step 106, and the waist groove is not through. An outlet end waist groove 109 is designed between the outlet end flow channel 110 and the central through hole 105, and the opening end of the outlet end waist groove 109 is on the upper second step 104, and the waist groove is not through. At this time, the inlet end flow channel 107, the inlet end waist groove 108, the lower double-headed diaphragm 8, the outlet end waist groove 109, the upper diaphragm 12 and the outlet end flow channel 110 form a complete flow channel.

[0056] Actuator top portion 13: The actuator top portion 13 mainly functions as a valve cover and is positioned in the installation direction. An air inlet hole 113 is designed on the actuator top portion 13 as a pressure source. At the same time, a positioning block 111 and a sealing groove 112 are designed at the lower end of the actuator top portion 13. An O-ring 10 is installed in the sealing groove 112 to achieve connection and sealing between the actuator top portion 13 and the mechanism body 9. At the same time, a diaphragm groove is designed below the actuator top portion 13, and the diaphragm groove and the upper diaphragm 12 form an air cavity.

[0057] Actuator bottom end 6: The actuator bottom end 6 is designed with two cylindrical grooves. The large cylindrical groove is used as a space for installing the spring assembly. The outer diameter of the small cylindrical groove is consistent with the inner diameter of the inner spring 1. It is mainly used to fix the spring assembly and guide the spring assembly. The inner diameter of the small cylindrical groove is slightly larger than the outer diameter of the cylindrical shaft of the actuator shaft 7, providing installation space for the actuator shaft and vertically guiding the actuator shaft 7. The cylindrical groove is mainly used to install the spring assembly. The spring assembly includes an inner spring 1 and an outer spring 2. The inner spring 1 is sleeved inside the outer spring 2. The length of the inner spring 1 is greater than the length of the outer spring 2. The stiffness of the outer spring 2 is greater than the stiffness of the inner spring 1, so as to provide a hierarchical elastic force.

[0058] Sealing assembly: mainly includes upper diaphragm 12, diaphragm connecting column 11 and lower double-headed diaphragm 8. It is composed of actuator shaft 7, upper diaphragm 12 is installed between actuator top end 13 and mechanism body 9, lower double-headed diaphragm 8 is installed between mechanism body 9 and actuator bottom end 6, upper diaphragm 12 and lower double-headed diaphragm 8 are connected through diaphragm connecting column 11, the other side of upper diaphragm 12 is connected to actuator shaft 7, and actuator shaft 7 is installed in the small cylindrical groove of actuator bottom end 6.

[0059] The working principle of the constant pressure valve of the present invention is as follows: the prerequisite is that the air source pressure is equal to the elastic force of the spring assembly. When the fluid enters the constant pressure valve from the inlet, the fluid passes through the entire flow channel. At this time, at the lower double-headed diaphragm 8, the fluid applies a downward force F1 to the double-headed diaphragm. At this time, the lower double-headed diaphragm 8 runs downward. At the same time, the spring assembly will give the lower double-headed diaphragm 8 an upward force P1. In the entire valve body cavity, the fluid will also give the upper diaphragm 12 an upward force F2. At the same time, the air source gives the upper diaphragm 12 a downward force P2 through the air inlet on the top of the actuator. Through the elastic force of the spring assembly and the pressure of the air source, the balance of the fluid pressure is achieved. At this time, F1+P2=F2+P1.

[0060] When the fluid pressure at the inlet increases, F1 increases, the opening and closing degree of the lower double-headed diaphragm 8 decreases, the opening and closing distance increases, and the force F2 exerted by the fluid pressure at the outlet on the upper diaphragm 12 increases. At this time, F1+P2>F2+P1, the opening and closing degree of the upper diaphragm 12 increases, and the opening and closing distance decreases. At this time, the outlet fluid pressure decreases, F1+P2=F2+P1.

[0061] When the fluid pressure at the inlet decreases, F1 decreases, the opening and closing degree of the lower double-headed diaphragm 8 increases, and the opening and closing distance decreases. The force F2 exerted by the fluid pressure at the outlet on the upper diaphragm 12 decreases. At this time, F1+P2<F2+P1, the opening and closing degree of the upper diaphragm 12 decreases, and the opening and closing distance increases. At this time, the outlet fluid pressure increases, and F1+P2=F2+P1.

[0062] The present invention designs a suitable flow channel structure, which is suitable for different media, including fluid media and gas media.

[0063] The present invention selects PTFE, a material currently required in the semiconductor field, and can meet the cleanliness requirements of semiconductor production. At the same time, elastic parts such as spring components are not in the fluid cavity, ensuring the cleanliness of the fluid area.

[0064] The present invention realizes the function of dynamically balancing the fluid pressure and achieves stable output of the fluid pressure through appropriate structural design.

[0065] The present invention adopts pneumatics as a power source for adjusting pressure, thereby achieving more stable adjustment of fluid pressure.

[0066] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implying the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0067] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, it can be a mechanical connection, it can be an electrical connection, it can be a direct connection, it can be indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A pneumatic constant pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing, comprising, from top to bottom, a mechanism body (9) and a mounting base plate (4); Features: An inlet flow channel (107) and an outlet flow channel (110) are sequentially arranged on the mechanism body (9) from left to right; an upper first step (101) and an upper second step (104) are sequentially arranged on the inner side of the top of the mechanism body (9) from outside to inside; a lower first step (103) and a lower second step (106) are sequentially arranged on the inner side of the bottom of the mechanism body (9) from outside to inside; a central through hole (105) is provided in the middle of the inner side of the upper second step (104); an outlet waist groove (109) connected to the outlet flow channel (110) is provided on the right side of the top of the upper second step (104); and an inlet waist groove (108) connected to the inlet flow channel (107) is provided on the left side of the bottom of the lower second step (106); Also included are an actuator assembly and a seal assembly; The actuator assembly comprises, from top to bottom, an actuator top end (13) and an actuator bottom end (6), wherein the actuator top end (13) is mounted on the top of an actuator body (9), the actuator bottom end (6) is mounted on the bottom of the actuator body (9), the mounting base plate (4) is mounted on the bottom of the actuator bottom end (6), an actuator shaft (7) is mounted in the actuator bottom end (6), and an air inlet hole (113) is opened on the top of the actuator top end (13); The sealing assembly includes, from top to bottom, an upper diaphragm (12), a diaphragm connecting column (11) and a lower double-headed diaphragm (8), wherein the diaphragm connecting column (11) is located in a central through hole (105), the upper diaphragm (12) installed on the top of the diaphragm connecting column (11) is located between the top end (13) of the actuator and the main body (9) of the actuator, and the lower double-headed diaphragm (8) installed on the bottom of the diaphragm connecting column (11) is connected to the actuator shaft (7) below.

2. A pneumatic constant pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing as claimed in claim 1, characterized in that: It also includes a spring assembly located at the inner side of the bottom of the bottom end portion (6) of the actuator, and the actuator shaft (7) is in contact with the spring assembly below.

3. A pneumatic constant pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing as claimed in claim 2, characterized in that: The spring assembly comprises an inner spring (1) and an outer spring (2) from the inside to the outside, the working stroke of the inner spring (1) is greater than the working stroke of the outer spring (2), and the spring stiffness of the outer spring (2) is greater than the spring stiffness of the inner spring (1).

4. A pneumatic constant pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing as claimed in claim 1, characterized in that: The top end portion (13) of the actuator, the actuator body (9), the bottom end portion (6) of the actuator and the mounting base plate (4) are connected together via a plurality of bolts (16).

5. A pneumatic constant pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing as claimed in claim 1, characterized in that: The head of the bolt (16) is located in a first mounting hole in the top end (13) of the actuator, and an open gasket (15) and a flat gasket (14) are installed in sequence from top to bottom between the lower part of the head of the bolt (16) and the first mounting hole, and the tail of the bolt (16) is installed in a second mounting hole in the mounting base plate (4) through a nut 5).

6. A pneumatic constant pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing as claimed in claim 5, characterized in that: Rubber plugs (3) are installed on the outer sides of the first mounting hole and the second mounting hole.

7. A pneumatic constant pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing as claimed in claim 1, characterized in that: A positioning groove (100) is arranged on the outer side of the top of the mechanism body (9); a positioning block (111) adapted to the positioning groove (100) is arranged on the outer side of the bottom of the top end portion (13) of the actuator directly above the positioning groove (100); a sealing groove (112) is arranged on the inner side of the positioning block (111); and an O-ring (10) is installed in the sealing groove (112).

8. A pneumatic constant pressure diaphragm valve for delivering chemical liquid in semiconductor manufacturing as claimed in claim 1, characterized in that: A sealing rib (102) is provided at the inner middle portion of the upper first step (101) and at the inner middle portion of the lower first step (103).

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