A double diaphragm leak-proof switch valve

Abstract

The present invention discloses a switch valve with double diaphragms for leakage prevention, which comprises a valve body, two groups of diaphragms and a valve rod. The valve body includes a longitudinally arranged installation cavity and liquid flow channels horizontally arranged at both ends of the installation cavity; a valve core tube body is arranged in the installation cavity, and a channel communicating the two sections of liquid flow channels is arranged in the valve core tube body; the valve body is provided with installation ports at both ends of the installation cavity, and an upper fixing seat and a lower fixing seat are respectively installed on the installation ports; the diaphragms are hermetically connected in the installation ports, and the center of the diaphragm can be deformed inwards or outwards when pressed; both ends of the valve rod are respectively supported between the two groups of diaphragms; the valve rod includes a rod body and a blocking part arranged at the lower part of the rod body, the rod body is arranged through the flow channel of the valve core tube body, and the diaphragm is extruded to drive the rod body to move along its axial direction and make the blocking part move away from or block the bottom end of the valve core tube body. The switch valve of the present invention has a compact structure, good sealing performance and good corrosion resistance, and improves the service life of the valve group when transporting highly corrosive fluids.

Description

Technical Field

[0001] The present invention relates to the technical field of switching valves, and in particular to a switching valve with double diaphragms for preventing leakage. Background Art

[0002] At present, in the domestic semiconductor industry, valve products for controlling highly corrosive fluids such as strong acids and strong alkalis highly rely on imports. Domestic valves mainly use sealing rings for sealing, but using sealing rings is prone to the following problems: 1. The sealing rings are prone to wear, and the longer the time, the greater the possibility of leakage; 2. The sealing rings are prone to being extruded and deformed, resulting in damage and causing liquid leakage. In the application field of highly corrosive fluid resistance, there are still great deficiencies in the design of switching valves using non-sealing ring structures and non-metallic materials. Summary of the Invention

[0003] Object of the Invention: The object of the present invention is to provide a switching valve with double diaphragms for preventing leakage, so as to improve the controllability, sealing performance, and durability of the opening and closing valve in transporting highly corrosion-resistant fluids.

[0004] Technical Solution: A switching valve with double diaphragms for preventing leakage according to the present invention, the switching valve includes:

[0005] A valve body, the valve body includes a longitudinally arranged installation cavity and liquid flow channels horizontally provided at both ends of the installation cavity; a valve core tube body is provided in the installation cavity, a channel communicating the two inlet and outlet sections of the liquid flow channel is provided in the valve core tube body, and a conical guiding surface is correspondingly provided between the valve core tube body and the inlet end of the liquid flow channel; the valve body is respectively provided with installation ports at the upper and lower ends of the installation cavity.

[0006] Two groups of diaphragms, the diaphragms are made of PTFE material; the diaphragms are hermetically connected in the installation ports, and pressing the center of the diaphragms can cause deformation inward or outward.

[0007] A valve stem, both ends of the valve stem are respectively supported between the two groups of diaphragms; the valve stem includes a rod body and a plugging portion provided at the lower part of the rod body, the rod body is disposed through the flow channel of the valve core tube body, squeezing the diaphragms drives the rod body to move along its axial direction and makes the plugging portion move away from or plug the bottom end of the valve core tube body.

[0008] A valve stem driving assembly, the valve stem driving assembly is correspondingly installed on the installation port at the upper end of the valve body and presses the corresponding diaphragm tightly in the installation port; the valve stem driving assembly can squeeze the diaphragm downward to cause deformation.

[0009] A lower fixing seat, the lower fixing seat presses the corresponding diaphragm tightly in the installation port, a spring cavity is provided in the lower fixing seat, and a return spring for supporting and connecting the corresponding diaphragm is provided in the spring cavity.

[0010] Preferably, an installation step is provided at the outer end of the installation port, and the diameter of the installation step is larger than the diameter of the installation cavity.

[0011] The diaphragm includes a cap body and a sealing ring body concentrically arranged on the periphery of the cap body. The inner periphery of the sealing ring body is integrally connected to the periphery of the cap body through an elastic thin sheet; a column hole is provided inside the cap body, and an annular turned edge is provided on the periphery of the cap body; the sealing ring body is pressed tightly within the installation step, and the cap body deforms axially along with the elastic thin sheet.

[0012] Preferably, an annular clamping groove is provided at the root of the installation step; a sealing clamping ring is provided circumferentially on the inner side of the sealing ring body, and the sealing clamping ring is clamped within the annular clamping groove.

[0013] Preferably, the valve stem driving assembly is a manual driving assembly. The manual driving assembly includes an upper fixing seat pressed tightly on the installation port. The top end of the upper fixing seat is movably connected with an opening and closing knob, and a conduction assembly is movably connected within the upper fixing seat. The upper end of the conduction assembly is in transmission connection with the opening and closing knob, and the lower end of the conduction assembly is fixedly connected to the center of the corresponding diaphragm.

[0014] Preferably, the conduction assembly includes a conduit and a pressing ring provided at the top end of the conduit. A support spring is sleeved on the conduit and pressed tightly between the pressing ring and the diaphragm.

[0015] Preferably, the valve stem driving assembly is a pneumatic driving assembly. The pneumatic driving assembly includes a cylinder block pressed tightly on the installation port and a cylinder head body threadedly connected to the cylinder block;

[0016] A guide sleeve is provided at the center of the lower end of the cylinder block. A driving piston is movably connected within the cylinder block. An air cavity is provided at the top end of the driving piston, and a driving column sleeved within the guide sleeve is provided at the lower end of the driving piston. The driving column is connected to the center of the diaphragm;

[0017] An air inlet interface and a nozzle provided inside the air inlet interface are provided at the top end of the cylinder head body. The nozzle extends into the air cavity.

[0018] Preferably, an O-ring seal is provided between the top end surface of the cylinder block and the cylinder head body;

[0019] An annular edge groove is provided on the outer circumference of the driving piston, and a V-ring seal is provided within the annular edge groove.

[0020] Preferably, a spring pressing tube is slidably provided within the spring cavity. The top end of the spring pressing tube is sleeved on the corresponding cap body, and the return spring is pressed tightly within the spring pressing tube.

[0021] Preferably, a snap ring is provided at the bottom end of the valve core tube body; the sealing portion is an inverted frustum shape, and an annular cut-off groove is provided along the axis of the rod body at the bottom of the sealing portion, and the snap ring can be correspondingly clamped in the cut-off groove; a tapered inclined surface is provided at the connection between the rod body and the sealing portion and inclines inward.

[0022] Preferably, a connecting column A is provided at the top end of the rod body, and a connecting column B is provided at the bottom end of the sealing portion, and the connecting column A and the connecting column B are respectively clamped in the column holes of the corresponding caps.

[0023] Beneficial effects: Compared with the prior art, the present invention has the following outstanding advantages:

[0024] 1. The on-off valve of the present invention has a compact structure, good sealing performance, good corrosion resistance, and improves the service life of the valve group when transporting highly corrosive fluids;

[0025] 2. The valve core tube body of the valve body is correspondingly provided with a tapered guide surface corresponding to the liquid flow passage inlet section. After the liquid passes through the liquid flow passage inlet section and impacts on the tapered guide surface, it can not only reduce the impact and noise of the liquid on the valve core tube body, but also guide the liquid to the inlet end of the valve core tube body, improving the flow efficiency of the valve body;

[0026] 3. The diaphragm is made of PTFE material, and the PTFE diaphragm has high corrosion resistance; this diaphragm structure can form a good seal with the valve body while meeting its deformation requirements, improving the leak-proof performance of the valve body;

[0027] 4. A snap ring is provided at the bottom end of the valve core tube body, the sealing portion of the valve stem is an inverted frustum shape, and an annular cut-off groove is provided along the axis of the rod body at the bottom of the sealing portion. The snap ring can be correspondingly clamped in the cut-off groove, thereby improving the closing effect of the valve core tube body and the valve stem and preventing liquid leakage when the valve body is in the closed state;

[0028] 5. The conduction assembly, pneumatic drive assembly and return spring provided in the valve body cooperate to efficiently realize the closing or connection of the on-off valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a top view of the structure of the manual on-off valve of the present invention;

[0030] Figure 2 is Figure 1 a sectional view of the structure of the manual on-off valve in the A-A direction (the on-off valve is in the open state);

[0031] Figure 3 is Figure 2 a schematic diagram of the structure of the manual on-off valve in the closed state;

[0032] Figure 4 is Figure 2 a schematic diagram of the enlarged structure at A of the manual on-off valve;

[0033] Figure 5 is Figure 3 The enlarged structural schematic diagram of the manual on-off valve at position B;

[0034] Figure 6 The structural sectional view of the pneumatic on-off valve of the present invention;

[0035] Figure 7 is Figure 6 The internal structural schematic diagram of the cylinder;

[0036] Figure 8 is Figure 2 The sectional view of the diaphragm along its radial direction;

[0037] Figure 9 is Figure 2 The sectional view of the valve stem along its axial direction.

[0038] Reference numerals:

[0039] 100, on-off valve;

[0040] 1, valve body; 11, liquid flow channel; 12, valve core tube body; 13, snap ring; 14, installation port; 15, installation step; 16, annular clamping groove; 17, installation cavity; 18, threaded connection area;

[0041] 2, upper fixing seat; 21, seat body; 22, closed mouth; 23, locking nut;

[0042] 3, lower fixing seat; 31, spring cavity; 32, connecting cap; 33, spring pressing tube;

[0043] 4, conduction component; 41, pressure ring; 42, conduit; 43, tube hole; 44, support spring;

[0044] 5, diaphragm; 51, cap body; 52, column hole; 53, annular flange; 54, elastic thin sheet; 55, sealing ring body; 56, sealing snap ring;

[0045] 6, valve stem; 61, rod body; 62, connecting column A; 63, blocking part; 64, truncation groove; 65, conical inclined plane; 66, support step; 67, connecting column B;

[0046] 7, return spring;

[0047] 8, opening and closing knob;

[0048] 9, connecting pipe nut;

[0049] 20. Pneumatic drive assembly; 201. Cylinder block; 202. Cylinder head; 203. Intake interface; 204. Nozzle; 205. O-ring seal; 206. Driving piston; 207. Annular edge groove; 208. Air chamber; 209. V-ring seal; 210. Driving column; 211. Guide sleeve; 212. Air hole. Detailed implementation mode

[0050] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the following will combine the accompanying drawings of the embodiments of the present invention Figures 1 - 9 to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope protected by the present invention.

[0051] Embodiment 1:

[0052] As Figures 1 - 5 shown, a double-diaphragm leak-proof switching valve of the present invention. In this embodiment, the switching valve 100 is a manual switching valve. The switching valve 100 includes a valve body 1. The valve body 1 includes a longitudinally arranged installation cavity 17 and liquid flow channels 11 horizontally provided at both ends of the installation cavity 17. The liquid flow channels 11 include an inlet section and an outlet section. The installation cavity 17 separates the inlet section and the outlet section of the liquid flow channel. A valve core tube 12 is provided in the installation cavity 17. A channel communicating the inlet and outlet sections of the liquid flow channel 11 is provided in the valve core tube 12. The valve core tube 12 is provided with a conical diversion surface corresponding to the inlet section of the liquid flow channel 11. After the liquid impacts on the conical diversion surface after passing through the inlet section of the liquid flow channel, it can not only reduce the impact and noise of the liquid on the valve core tube, but also divert the liquid to the inlet end of the valve core tube, improving the flow efficiency of the valve body.

[0053] As Figures 2 - 3 and Figure 8As shown in the figure, the valve body 1 is provided with installation ports 14 at the upper and lower ends of the installation cavity 17. The outer ends of the installation ports 14 are provided with installation steps 15. The diameter of the installation steps 15 is larger than that of the installation cavity 17. An annular clamping groove 16 is provided at the root of the installation steps 15. A diaphragm 5 is hermetically clamped inside the installation steps 15. The diaphragm 5 is made of PTFE material. The PTFE diaphragm has high corrosion resistance, thereby improving the corrosion resistance of the valve body. The diaphragm 5 includes a cap body 51 and a sealing ring body 55 concentrically arranged on the outer periphery of the cap body. The inner periphery of the sealing ring body 55 is integrally connected to the outer periphery of the cap body 51 through an elastic thin sheet 54. A column hole 52 is provided inside the cap body 51, and an annular flange 53 is provided on the outer periphery of the cap body 51. The sealing ring body 55 is pressed tightly inside the installation steps 15. A sealing snap ring 56 is provided on the inner circumference of the sealing ring body 55 in the circumferential direction. The sealing snap ring 56 is clamped in the annular clamping groove. Pressing the cap body 51 of the diaphragm can cause the elastic thin sheet 54 to deform inward or outward along its axial direction.

[0054] As Figures 2 - 3 and Figure 9 shown in the figure, a valve stem 6 is cooperatively provided with the valve core tube body 12. The valve stem 6 includes a rod body 61 and a plugging portion 63 provided at the lower part of the rod body. The rod body 61 is penetrated and arranged inside the flow channel of the valve core tube body 12. A column hole 52 is provided inside the cap body 51. A connecting column A 62 is provided at the top end of the rod body 61, and a connecting column B 67 is provided at the bottom end of the plugging portion 63. A supporting step 66 is formed along the circumference of the connecting column B on the plugging portion 63. The supporting step 66 can form a stable support with the annular flange 53 of the cap body. Both ends of the valve stem 6 are respectively clamped inside the column hole 52 of the cap body between two diaphragms through the connecting column A 62 and the connecting column B 67. Pressing the cap body of the diaphragm can drive the rod body 61 to move along its axial direction, so that the plugging portion 63 is far away from or plugs at the bottom end of the valve core tube body 12, and thus the opening and closing valve can be opened or closed. An inwardly inclined conical slope 65 is provided at the connection between the rod body 61 and the plugging portion 63. When the opening and closing valve is in the open state, the liquid can flow smoothly through the channel of the valve core tube body.

[0055] As Figures 3 - 4 shown in the figure, a snap ring 13 is provided at the bottom end of the valve core tube body 12. The plugging portion 63 is an inverted frustum shape. An annular cut-off groove 64 is provided along the axis of the rod body 61 at the bottom of the plugging portion. The snap ring 13 can be correspondingly clamped in the cut-off groove 64 to improve the closing effect between the valve core tube body and the plugging portion and prevent liquid leakage when the valve body is in the closed state.

[0056] As Figures 2 - 3As shown, a valve rod driving assembly is correspondingly provided on the installation port 14 at the upper end of the valve body 1. This valve rod driving assembly is a manual driving assembly, which includes an upper fixing seat 2 pressed on the installation port 14. The upper fixing seat 2 includes a seat body 21 with an inner cavity inside. At the top of the seat body 21, there is a closed constriction 22, and the connecting rod of the opening and closing knob 8 extends into the closed constriction 22. A locking nut 23 is threadedly connected to the outer periphery of the seat body 21. A lower fixing seat 3 is correspondingly provided on the installation port 14 at the lower end of the valve body 1. The inner diameters of the upper fixing seat and the lower fixing seat are larger than the inner diameter of the sealing ring body 55 and smaller than the outer diameter of the sealing ring body 55. The upper fixing seat or the lower fixing seat can correspondingly press the sealing ring body 55 in the installation step 15, so that the diaphragm 5 can be hermetically connected to the installation port of the valve body through the sealing ring body, improving the leak-proof performance of the valve body.

[0057] As Figure 2 shown, a conduction assembly 4 is movably connected inside the upper fixing seat 2. The conduction assembly 4 includes a conduit 42 and a retaining ring 41 provided at the top of the conduit. The outer diameter of the retaining ring 41 is the same as the inner diameter of the upper fixing seat 2, so that the conduit 42 can slide up and down inside the upper fixing seat 2. A through hole 43 is provided in the retaining ring 41 and the conduit 42. The top of the retaining ring 41 is fixedly connected to the lower end of the rod body of the opening and closing knob 8. An annular flange 53 is provided on the outer periphery of the cap body 51. The lower end of the conduit 42 is fixedly sleeved on the cap body 51, and the bottom surface of the conduit 42 is supported on the annular flange 53 to form a stable support. A support spring 44 is sleeved on the conduit 42 and pressed between the retaining ring 41 and the annular flange 53. During operation, rotating the opening and closing knob 8 can drive the conduit to move downward and push the cap body 51 to move downward. During the downward movement of the cap body 51, the valve rod 6 and the valve core tube 12 can be opened.

[0058] As Figure 3 and Figure 5 shown, a spring cavity 31 is provided inside the lower fixing seat 3. A spring pressure tube 33 is slidably provided inside the spring cavity 31. The top of the spring pressure tube 33 is sleeved on the corresponding cap body 51 and stably supported on the annular flange 53 outside the corresponding cap body. A return spring 7 is pressed inside the spring pressure tube 33, and the lower end of the return spring 7 is supported and pressed against the bottom end of the spring cavity 31. The lower fixing seat 3 is connected to the installation port 14 through a connecting cap 32. When the opening and closing knob is rotated in the reverse direction to release the pressure, under the action of the support spring 44, the conduit 42 and the retaining ring 41 move upward, and the cap body of the corresponding diaphragm resets upward; the cap body of the diaphragm at the lower end of the blocking portion 63 moves upward under the support of the return spring 7 and jacks up the valve rod 6 to move upward to close with the valve core tube 12.

[0059] As Figure 1 shown, a threaded connection area 18 is provided on the outer periphery of the inlet and outlet ends of the valve body 1. A connection pipe nut 9 is connected to the end of the threaded connection area 18. The connection pipe nut 9 can fixedly and hermetically connect the material conveying pipe to the inlet and outlet ends of the valve body 1.

[0060] Embodiment 2:

[0061] like Figure 6 As shown, the switch valve 100 in this embodiment is a pneumatic switch valve, and the main structure of the switch valve is the same as that of the embodiment 1, except that in this embodiment, the valve stem drive assembly is a pneumatic drive assembly 20, and the pneumatic drive assembly 20 includes a cylinder body 201 pressed against the mounting port 14 and a cylinder cover body 202 threadedly connected to the cylinder body; a guide sleeve 211 is provided at the center of the lower end of the cylinder body 201, and a drive piston 206 is movably connected in the cylinder body 201, and an air cavity 208 is provided at the top of the drive piston 206, and a drive column 210 sleeved in the guide sleeve is provided at the lower end of the drive piston 206, and the drive column 210 is fixedly connected to the cap body 51 of the diaphragm 5. An air inlet interface 203 and a nozzle 204 on the inner side of the air inlet interface are provided at the top of the cylinder cover body 202, and the nozzle 204 extends into the air cavity 208. A threaded area is provided on the inner periphery of the air inlet interface 203, which can be threadedly connected to the air inlet pipe port. When working, the air inlet pipe can blow air into the air cavity through the nozzle 204, thereby pushing the driving piston 206 to move downward, and the driving column 210 at the lower end of the driving piston pushes the valve stem 6 downward, thereby opening the switch valve. The pneumatic switch valve of this embodiment has a short driving stroke, and the switch valve can be accurately controlled by accurately adjusting the intake volume.

[0062] like Figure 7 As shown, an O-ring 205 is provided between the top surface of the cylinder body 201 and the cylinder head body 202; an annular groove 207 is provided on the outer circumference of the driving piston 206, and a V-ring 209 is provided in the annular groove 207. This arrangement can improve the sealing performance of the pneumatic drive assembly and avoid gas energy loss.

[0063] Optionally, the side wall of the cylinder body 201 is provided with an air hole 212 connected to the cavity below the driving piston 206. When the pneumatic drive assembly 20 is inhaled, the driving piston 206 moves downward and discharges the air in the cylinder body below the driving piston through the air hole 212; when the switch valve is closed, the air source is closed, and the valve stem 6 lifts the cap body of the diaphragm upward under the action of the return spring 7, and the cap body then lifts the driving piston 206. In this process, when the driving piston 206 moves upward, air can be returned to the cylinder body through the air hole. This arrangement is conducive to maintaining the gas balance in the cylinder and improving the driving efficiency of the pneumatic drive assembly 20.

[0064] The working principle or working method of the switch valve of the present invention is as follows:

[0065] During operation, when the valve body 1 is in a closed state, the return spring 7 is in an open state, and lifts the cap body 51 of the diaphragm at the lower end of the valve stem upward, and the cap body 51 further lifts the valve stem 6 to move upward, and the valve stem 6 correspondingly lifts the diaphragm cap body 51 at its upper end to move upward. In this process, the cap body 51 elastically deforms the elastic sheet 54 to meet the upward movement of the valve stem 6, so that the blocking portion 63 is closed with the lower end of the valve core tube body 12 (such as Figure 3 When the valve body 1 is in the open state, by rotating the opening and closing knob 8 or inflating the pneumatic drive assembly 20 to apply downward pressure, the cap body 51 of the diaphragm at the upper end of the valve stem is pushed downward, and the cap body 51 then pushes the valve stem 6 downward, and the valve stem 6 correspondingly pushes the diaphragm cap body 51 at its lower end downward, thereby squeezing the return spring 7 into a compressed state. In this process, the cap body 51 meets the downward movement of the valve stem 6 through the elastic deformation of the elastic sheet 54, so that the blocking portion 63 is away from the valve body (such as the lower end of the valve core tube body 12) that is opened. Figure 2 status shown).

[0066] The above are preferred embodiments of the present invention. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A switch valve with double diaphragms for leak prevention, characterized in that, The described switching valve (100) includes: A valve body (1), the valve body (1) includes a longitudinally arranged installation cavity (17) and liquid flow channels (11) horizontally arranged at both ends of the installation cavity (17); a valve core tube body (12) is arranged in the installation cavity (17), a channel communicating the two inlet and outlet sections of the liquid flow channel (11) is arranged in the valve core tube body (12), and a conical guide surface is correspondingly arranged between the valve core tube body (12) and the inlet end of the liquid flow channel (11); installation ports (14) are respectively arranged at the upper and lower ends of the valve body (1) where the installation cavity (17) is located; an installation step (15) is arranged at the outer end of the installation port (14), and the diameter of the installation step (15) is larger than the diameter of the installation cavity (17). Two groups of diaphragms (5), the diaphragms (5) are made of PTFE material; the diaphragms (5) are hermetically connected in the installation ports (14), and pressing the center of the diaphragms (5) can cause deformation inward or outward; the diaphragm (5) includes a cap body (51) and a sealing ring body (55) concentrically arranged on the outer periphery of the cap body, the inner periphery of the sealing ring body (55) is integrally connected to the outer periphery of the cap body (51) through an elastic thin sheet (54); a column hole (52) is arranged in the cap body (51), and an annular flange (53) is arranged on the outer periphery of the cap body (51); the sealing ring body (55) is pressed tightly in the installation step (15), and the cap body (51) deforms along its axial direction through the elastic thin sheet (54). A valve stem (6), both ends of the valve stem (6) are respectively supported between two groups of diaphragms (5); the valve stem (6) includes a stem body (61) and a blocking portion (63) arranged at the lower part of the stem body, the stem body (61) is arranged through the flow channel of the valve core tube body (12), squeezing the diaphragm (5) drives the stem body (61) to move along its axial direction and enables the blocking portion (63) to move away from or block the bottom end of the valve core tube body (12); a snap ring (13) is arranged at the bottom end of the valve core tube body (12); the blocking portion (63) is an inverted frustum shape, an annular cut-off groove (64) is arranged along the axis of the stem body (61) at the bottom of the blocking portion, and the snap ring (13) can be correspondingly clamped in the cut-off groove (64); a conical inclined surface (65) inclined inward is arranged at the connection between the stem body (61) and the blocking portion (63). A valve stem driving assembly, the valve stem driving assembly is correspondingly installed on the installation port (14) at the upper end of the valve body, and presses the corresponding diaphragm (5) tightly in the installation port (14); the valve stem driving assembly can squeeze the diaphragm (5) downward to cause deformation. A lower fixing seat (3), the lower fixing seat (3) presses the corresponding diaphragm (5) tightly in the installation port (14), a spring cavity (31) is arranged in the lower fixing seat (3), and a return spring (7) for supporting and connecting the corresponding diaphragm (5) is arranged in the spring cavity (31).

2. The double-diaphragm leak-proof on-off valve according to claim 1, characterized in that, An annular clamping groove (16) is arranged at the root of the installation step (15); a sealing clamping ring (56) is arranged on the inner circumference of the sealing ring body (55) in the circumferential direction, and the sealing clamping ring (56) is clamped in the annular clamping groove.

3. The double-diaphragm leak-proof switching valve according to claim 1, wherein The valve stem drive assembly is a manual drive assembly. The manual drive assembly includes an upper fixing seat (2) pressed on the installation port (14). The top of the upper fixing seat (2) is movably connected with an opening and closing knob (8). And a conduction assembly (4) is movably connected inside the upper fixing seat (2). The upper end of the conduction assembly (4) is in transmission connection with the opening and closing knob (8), and the lower end of the conduction assembly (4) is fixedly connected to the center of the corresponding diaphragm (5).

4. The double-diaphragm leak-proof switching valve according to claim 3, wherein The conduction assembly (4) includes a conduit (42) and a retaining ring (41) arranged at the top end of the conduit. A support spring (44) is sleeved on the conduit (42) and pressed between the retaining ring (41) and the diaphragm (5).

5. The double-diaphragm leak-proof switching valve according to claim 1, characterized in that, The valve stem drive assembly is a pneumatic drive assembly (20). The pneumatic drive assembly (20) includes a cylinder block (201) pressed on the installation port (14) and a cylinder head (202) threadedly connected to the cylinder block; A guide sleeve (211) is provided at the center of the lower end of the cylinder block (201). A driving piston (206) is movably connected inside the cylinder block (201). An air cavity (208) is formed at the top end of the driving piston (206). And a driving column (210) sleeved inside the guide sleeve is provided at the lower end of the driving piston (206). The driving column (210) is connected to the center of the diaphragm (5); An air inlet interface (203) is provided at the top end of the cylinder head (202), and a nozzle (204) is provided inside the air inlet interface. The nozzle (204) extends into the air cavity (208).

6. The double-diaphragm leak-proof on-off valve according to claim 5, wherein, An O-ring seal (205) is provided between the top surface of the cylinder block (201) and the cylinder head (202); An annular edge groove (207) is provided on the outer circumference of the driving piston (206), and a V-ring seal (209) is provided inside the annular edge groove (207).

7. The double-diaphragm leak-proof switching valve according to claim 1, characterized in that, A spring pressure tube (33) is slidably arranged inside the spring cavity (31). The top end of the spring pressure tube (33) is sleeved on the corresponding cap body (51), and the return spring (7) is pressed inside the spring pressure tube (33).

8. The double-diaphragm leak-proof on-off valve according to claim 1, wherein, A connecting column A (62) is provided at the top end of the rod body (61), and a connecting column B (67) is provided at the bottom end of the blocking part (63). The connecting column A (62) and the connecting column B (67) are respectively clamped in the column holes (52) of the corresponding cap body.

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