Double-movable gate valve for chemical production and using method of double-movable gate valve

Abstract

The invention relates to a double-movable gate valve for chemical production and a using method thereof.The double-movable gate valve comprises a valve body, valve decks are detachably and fixedly connected to the upper end and the lower end of the valve body, two valve seats are detachably and fixedly connected to the inner wall of the valve body, a piston cylinder extending leftwards and rightwards is arranged between the two valve seats, and pistons are slidably connected to the left end and the right end of the piston cylinder; flashboards are detachably and fixedly connected to the ends, away from each other, of the two pistons, the two flashboards are opposite to the two valve seats respectively, guide blocks are fixedly connected to the ends, close to each other, of the two pistons, and guide slopes are arranged on the sides, close to each other, of the two guide blocks; a hollow valve rod is detachably and fixedly connected to the top of the piston cylinder, a hollow extrusion rod is arranged in an inner cavity of the valve rod in a penetrating mode, two extrusion slopes are arranged at the lower end of the extrusion rod, and the two extrusion slopes are matched with the guide slopes of the two guide blocks respectively. Through the action of the extrusion rod, the two flashboards move horizontally in cooperation with an external fluid source, friction between the flashboards and ports is greatly reduced, and the gate valve is more durable and higher in sealing performance.

Description

Technical Field

[0001] The present invention relates to the technical field of gate valves, in particular to a double-movable gate valve for chemical production and a use method thereof. Background Art

[0002] In chemical production, gate valves are commonly used in chemical gas pipelines. Gate valves typically consist of a valve body and a gate disc. The valve body is provided with an inlet and outlet, and the gate disc is slidably connected to the valve body. The movement of the gate disc controls the opening or closing of the inlet and outlet.

[0003] For example, CN106439776A discloses an adaptive once-through boiler drain expansion control device. This device essentially adopts the structure of a common gate valve, using a trapezoidal valve core (i.e., gate) that slides up and down to seal the input and output ports on both sides. However, because the gate of existing gate valves moves vertically up and down, it creates significant vertical friction with the ports when opening or closing, causing wear on the ports and the gate, shortening the valve's service life. Excessive wear can lead to leakage, resulting in insufficient sealing and compromising the sealing effect. Summary of the Invention The present invention addresses the shortcomings of existing technologies and provides a double-disc gate valve for chemical production and its use method. This valve utilizes a dual-disc structure, with a drive assembly driving the two discs to move horizontally, away from the valve seats on either side. This significantly reduces friction between the discs and the valve seat, resulting in increased durability and improved sealing. Furthermore, the valve seat and valve body, as well as the valve stem, extrusion rod, and discs, are all separated, making each component easy to disassemble, assemble, and replace, saving costs and facilitating ease of use.

[0004] The present invention is achieved through the following technical solution: a double-movable gate valve for chemical production, including a valve body, with valve covers fixedly connected to the upper and lower ends of the valve body, and characterized in that: two left and right valve seats opposite to each other are provided on the inner wall of the valve body, two delivery pipes corresponding to the two valve seats are fixedly connected to the valve body, a piston cylinder is provided between the two valve seats, the left and right ends of the piston cylinder are slidably connected to pistons, the ends of the two pistons away from each other are fixedly connected to gate plates, the two gate plates are respectively sealed with the two valve seats, a valve stem is fixedly connected to the top of the piston cylinder, and the upper end of the valve stem extends to the outside through the valve cover; and a drive assembly for driving the two pistons to slide away from each other along the axial direction of the piston cylinder.

[0005] This solution uses a drive assembly to drive the two pistons away from each other, thereby causing the two gates to move horizontally and seal with the corresponding valve seats. When the valve is closed, pressure is released, and the friction between the gate and the valve seat is greatly reduced, thereby effectively reducing wear between the valve seat and the gate, thereby increasing the service life of the valve.

[0006] As an optimization, the valve stem is hollow, and the ends of the two pistons that are close to each other are fixed with guide blocks, and the sides of the two guide blocks that are close to each other are provided with guide slopes; the driving component is an extrusion rod that is inserted into the valve stem and slides up and down, and the lower end of the extrusion rod extends through the piston cylinder to between the two guide blocks, and the lower end of the extrusion rod is provided with two extrusion slopes, which respectively cooperate with the guide slopes of the two guide blocks. In this optimization solution, the extrusion rod slides downward along the valve stem, so that the extrusion slopes at the lower end of the extrusion rod fit with the guide slopes of the two guide blocks. The extrusion rod squeezes the two guide blocks outward, causing the two guide blocks to move away from each other, thereby causing the two gates to move away from each other and press the two valve seats respectively, achieving a sealed connection between the gate and the valve seat, and thus achieving sealing of the delivery pipe opening.

[0007] As an optimization, the extrusion rod is fixedly connected to an air inlet pipe, extending along the length of the extrusion rod and penetrating the rod. The upper end of the air inlet pipe is connected to an external fluid source, which is then connected to an exhaust pipe. Both the air inlet pipe and the exhaust pipe are equipped with on-off valves. In this optimization solution, the external fluid source delivers high-pressure fluid into the piston cylinder via the air inlet pipe. This high-pressure fluid further squeezes the pistons on both sides, thereby further improving the seal between the gate and the valve seat, enhancing the sealing effect of the valve.

[0008] As an optimization, an annular vent cavity is formed between the extrusion rod and the valve stem. The inlet-side delivery pipe connects to the annular vent cavity via an intake pipe, while the outlet-side delivery pipe connects to the annular vent cavity via an exhaust pipe. Both the intake and exhaust pipes are equipped with on-off valves. In this optimized solution, after the extrusion rod drives the gates on either side to seal the valve seats, the fluid in the delivery pipe enters the annular vent cavity through the intake pipe. From there, it enters the piston cylinder, further squeezing and compressing the two gates. This self-delivered fluid further enhances the sealing effect, making it more convenient to use and eliminating the need for an external fluid source, thus reducing operating costs.

[0009] As an optimization, an annular groove is defined at the lower end of the valve stem, into which a guide ring is embedded. The inner diameter of the guide ring matches the outer diameter of the extrusion rod, and the inner wall of the guide ring is circumferentially defined with multiple ventilation grooves. This optimized solution uses the guide ring to guide the upward and downward movement of the extrusion rod, resulting in more stable sliding. The ventilation grooves on the guide ring facilitate the entry of gas into the piston cylinder.

[0010] As an optimization, a partition plate is fixedly attached to the piston cylinder between the two pistons, forming an air chamber between the pistons and the partition plate. The drive assembly comprises two intake pipes fixed to the valve stem. Both intake pipes extend through the valve stem and communicate with the two air chambers, respectively. Each intake pipe is connected to an external fluid source, each of which is connected to an exhaust pipe. Both intake and exhaust pipes are equipped with on / off valves. This optimization scheme uses high-pressure gas or liquid delivered into the air chamber by an external fluid source to squeeze and drive the pistons, thereby achieving a sealed connection between the gate and the valve seat. The partition plate divides the piston cylinder into two chambers, and air is supplied through two intake pipes, allowing the two pistons to slide independently. This allows the valve to be sealed by simply actuating the other piston if one piston leaks and is damaged. During maintenance, the damaged piston can be repaired, and the valve can remain operational even if one piston is damaged, making operation more economical.

[0011] As an optimization, both ends of the piston cylinder are fixed with outer sealing sleeves, and the two outer sealing sleeves are respectively sleeved on the two gate plates. This optimization solution improves the sealing between the piston and the piston cylinder through the sealing of the outer sealing sleeves.

[0012] As an optimization, a single-walled bellows is installed between the piston cylinder and the gate plate. One end of the single-walled bellows is sealed and fixed to the piston cylinder, and the other end of the single-arm bellows is sealed and fixed to the gate plate. This optimization solution can improve the sealing effect between the gate plate and the piston cylinder and prevent air leakage.

[0013] As an optimization, a hollow double-walled bellows is installed between the gate and the valve seat. This double-walled bellows is affixed to the valve seat, and a vent tube is affixed to the valve body. One end of this vent tube communicates with the inner cavity of the double-walled bellows, and an on-off valve is mounted on the vent tube. In this optimized solution, the gate and the double-armed bellows form a sealing contact, forming a secondary seal. High-pressure fluid is introduced into the double-walled bellows through the vent tube, creating close contact between the double-walled bellows and the gate, further improving sealing performance.

[0014] As an optimization, a hollow, annular rubber tube is installed between the gate and the valve seat. A vent tube is fixed to the valve body, one end of which communicates with the inner cavity of the rubber tube. An on-off valve is mounted on the vent tube. In this optimized solution, the gate and the rubber tube form a sealing contact, forming a secondary seal. High-pressure fluid is introduced into the rubber tube through the vent tube, maintaining close contact between the rubber tube and the gate, further improving the seal.

[0015] A method for using the above-mentioned double-movable gate valve for chemical production includes the following steps: sliding the valve stem downward to make the piston cylinder contact the limit column, and the gates on both sides of the piston cylinder are opposite to the valve seats on both sides of the valve body; driving the two pistons to slide away from each other, and then making the two gates move away from each other and press the two valve seats respectively, so that the gates and the valve seats are sealed and docked, and the gate is closed.

[0016] The beneficial effects of the present invention are as follows: the present invention adopts a double gate structure, and the driving assembly can slide up and down by using an extrusion rod, so that the two gates move away from each other horizontally and seal with the valve seats on both sides, thereby opening or sealing the delivery pipe port, and the friction between the gate and the valve seat is greatly reduced, thereby avoiding wear and making the valve more durable; After the two gates are sealed against the valve seats, high-pressure fluid is injected into the piston cylinder through the air inlet pipe. The high-pressure fluid is then injected into the space between the two pistons, thereby further pressurizing the two gates and improving the sealing effect between the gates and the valve seats. When the gate is docked with the valve seat, a first sealing structure is formed. When the gate is docked with the double-walled bellows or rubber tube, a second sealing structure is formed. High-pressure fluid is filled into the double-walled bellows or rubber tube through the vent pipe to make the double-walled bellows or rubber tube fit tightly with the gate, further improving the sealing effect and thus ensuring the sealing of the valve.

[0017] The piston cylinder is divided into two cavities by a partition plate. The driving assembly can use two air intake pipes to drive the two pistons to slide separately. The air supply through the two air intake pipes can make the two pistons slide independently. In this way, if one of the pistons is damaged by leakage, it is only necessary to drive the other piston to move to seal the valve. During maintenance, the damaged piston can be repaired. The valve can be used normally when one piston is damaged, making operation more economical and safer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a cross-sectional view of Example 1; Figure 2 This is a schematic diagram of the valve body structure of Example 1; Figure 3 This is a schematic diagram of the piston-cylinder structure of Example 1; Figure 4 for Figure 3 A magnified view of part A; Figure 5 This is a cross-sectional view of Example 2; Figure 6 This is a cross-sectional view of Example 3; Figure 7 for Figure 6 A magnified view of part B; Figure 8 This is a cross-sectional view of Example 4; Figure 9 Schematic diagram of the guide ring structure; Figure 10 This is a cross-sectional view of Example 5; Figure 11 for Figure 10 Magnified view of part C; As shown in the figure: 1. Valve body, 2. Valve cover, 3. Valve seat, 4. Piston cylinder, 5. Piston, 6. Gate, 7. Guide block, 8. Valve stem, 9. Extrusion rod, 10. Delivery pipe, 11. Insert ring, 12. Limit column, 13. Sealing gasket, 14. Outer sealing sleeve, 15. Third sealing ring, 16. Fourth sealing ring, 17. First sealing ring, 18. Guide slope, 19. Extrusion slope, 20. Second sealing ring, (21; 31; 41), Inlet pipe, (22; 32; 42), Exhaust pipe, 23. Switch valve, 24. Single-wall bellows, 25. Double-wall bellows, (26; 36), Vent pipe, 27. Guide ring, 271. Vent groove, 28. Annular ventilation cavity, 29. Partition plate, 30. Rubber tube. DETAILED DESCRIPTION

[0019] In order to clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods.

[0020] Example 1: like Figures 1 to 4 The figure shows a double-action gate valve for chemical production, comprising a valve body 1 with valve covers 2 removably fixed to the upper and lower ends of the valve body 1. Two valve seats 3, facing each other, are provided on the inner wall of the valve body 1. Two delivery pipes 10, corresponding to the two valve seats 3, are fixed to the valve body, forming the inlet and outlet of the valve.

[0021] Specifically, flanges are welded to the upper and lower ends of the valve body 1. The valve cover 2 is bolted to the flange, allowing for removable fixing of the valve body 1 and bonnet 2, facilitating disassembly. The valve seat 3 is bolted to the valve body 1, allowing for removable fixing of the valve seat 3 and easy removal and replacement of the valve seat 3. In this embodiment, the delivery pipe and valve body are welded together. One end of the delivery pipe 21 extends to the exterior of the valve body 1, and the other end extends to the interior of the valve body. The valve seat 3 is sleeved onto the port of the delivery pipe 10. During use, a flange can be welded to the end of the delivery pipe 21 located outside the valve body 1, facilitating connection to other pipelines.

[0022] A piston cylinder 4 is provided between the two valve seats 3. The piston cylinder 4 extends in the left-right direction, and pistons 5 are slidably connected to the left and right ends of the piston cylinder 4. Specifically, the piston cylinder 4 in this embodiment is a cylindrical structure, and the piston cylinder 4 is coaxially arranged with the two valve seats 3. The outer diameter of the piston 5 is adapted to the inner diameter of the piston cylinder 4, so that the piston 5 can slide axially along the piston cylinder 4. The piston cylinder 4 and the piston 5 are sealed by a first sealing ring 17. In this embodiment, a first sealing ring 17 is axially arranged and fixed on the inner wall of the piston cylinder 4. The inner diameter of the first sealing ring 17 is adapted to the outer diameter of the piston 5. The sealing of the first sealing ring 17 prevents fluid from entering the piston cylinder 4.

[0023] The ends of the two pistons 5 facing away from each other are each fixedly connected to a gate plate 6, which seals against the two valve seats 3. Specifically, in this embodiment, the gate plates 6 and pistons 5 are fixedly connected by screws. The screws are located at the ends of the gate plates 6 facing away from the pistons 5 and pass through the center of the gate plates 6 to connect with the pistons 5, thereby achieving a detachable connection between the gate plates 6 and the pistons 5, making it easy to remove and replace the gate plates 6. In this embodiment, a sealing gasket 13 is fixedly attached to the end of the gate plate 6 away from the piston 5. The sealing gasket 13 is an annular structure. The valve seat is also fixedly attached to the side of the gate plate close to the gate plate. When sealing, the sealing gasket 13 of the gate plate 6 is pressed against the sealing gasket 13 of the valve seat 3, achieving a sealing fit between the gate plate 6 and the valve seat 3, and improving the sealing performance.

[0024] In this embodiment, a limiting column 12 supporting the piston cylinder 4 is fixedly connected to the valve cover 2 below. When the piston cylinder 4 contacts the limiting column 12, the gate plates 6 on both sides of the piston cylinder 4 are just opposite to the valve seat 3, which makes it convenient for personnel to control the up and down movement of the piston cylinder 4 and facilitates the docking of the gate plates and the valve seat.

[0025] A valve stem 8 is fixed to the top of the piston cylinder 4. The upper end of the valve stem 8 extends through the valve cover 2 to the exterior of the valve body. The valve stem 8 is slidably connected to the valve cover. The upward and downward sliding movement of the valve stem 8 drives the upward and downward movement of the piston cylinder 4. Specifically, an insert ring 11 is fixed to the center of the top of the piston cylinder 4 in this embodiment. The insert ring 11 and the piston cylinder 4 are integrally formed. The inner diameter of the insert ring 11 is adapted to the outer diameter of the valve stem 8. The lower end of the valve stem 8 is inserted into the insert ring 11 and fixed with screws, making it easy to remove and replace the valve stem 8.

[0026] In this embodiment, the valve stem 8 and the insert ring 11 are sealed by a fourth sealing ring 16, ensuring a tight seal between the valve stem 8 and the insert ring 11 and preventing gas from entering therebetween. In this embodiment, the valve cover 2 and the valve stem 8 are sealed by a second sealing ring 20, providing a sealed sliding connection between the valve stem 8 and the valve cover 2, ensuring a tight seal between the valve stem 8 and the valve cover 2 and preventing gas from leaking out.

[0027] It also includes a drive assembly for driving the two pistons 5 to slide away from each other along the axial direction of the piston cylinder 4.

[0028] Specifically, the driving assembly described in this embodiment is an extrusion rod 9 that is inserted into the valve stem 8 and slides up and down. The valve stem 8 is hollow, and the ends of the two pistons 5 that are close to each other are fixed with guide blocks 7. The sides of the two guide blocks 7 that are close to each other are provided with guide slopes 18. The lower end of the extrusion rod 9 passes through the piston cylinder 4 and extends between the two guide blocks 7. The lower end of the extrusion rod 9 is provided with two extrusion slopes 19, and the two extrusion slopes 19 respectively cooperate with the guide slopes 18 of the two guide blocks 7.

[0029] The guide block 7 and the piston 5 are integrally formed. The guide block 7 has a frustum-shaped cross section, forming two upper and lower guide slopes 18. The lower end of the extrusion rod 9 has a trapezoidal cross section, forming two left and right extrusion slopes 19.

[0030] In this embodiment, the valve stem 8 and the extrusion rod 9 are sealed by the third sealing ring 15, so that the extrusion rod 9 and the valve stem 8 are sealed and slidably connected, ensuring the sealing between the valve stem 8 and the extrusion rod 9 and preventing gas leakage.

[0031] Preferably, in this embodiment, outer sealing sleeves 14 are fixedly attached to both ends of the piston cylinder 4. These outer sealing sleeves 14 are respectively fitted over the two gate plates 6, with the inner walls of the outer sealing sleeves 14 slidingly and sealingly engaging the outer walls of the gate plates 6. The outer diameters of the gate plates are the same as those of the piston cylinder. The outer sealing sleeves 14 are removably fixed to the piston cylinder 4 via bolts, facilitating removal and replacement of the outer sealing sleeves 14. When the gate plates 6 move left and right, the outer sealing sleeves provide dual internal and external sealing, ensuring a more reliable valve seal.

[0032] An internal sealing structure is formed between the piston cylinder 4 and the piston 5 through the first sealing ring 17, and an external sealing structure is formed by the outer sealing sleeve and the gate plate to ensure the sealing between the piston cylinder 4 and the piston 5 and prevent fluid from entering the piston cylinder.

[0033] In this embodiment, a seal monitoring port 31 is fixedly attached to each of the left and right outer walls of the valve body 1. Each of these ports houses an on / off valve. When the valve is closed, a sealed space is formed within the valve body. Nitrogen can be injected through one of the seal monitoring ports 31, completely sealing the valve stem, valve plates, and valve seat. This prevents toxic and hazardous fluids from leaking through the valve stem, while also preventing leaks between the gate plates and valve seats. A pressure gauge can be installed on the other seal monitoring port 31 to monitor internal pressure in real time, thereby monitoring the valve's sealing condition.

[0034] A method for using a double-action gate valve for chemical production includes the following steps: The valve stem 8 slides downward, driving the piston cylinder 4 to contact the limit column 12, causing the gates 6 on both sides of the piston cylinder 4 to face the valve seats 3 on both sides of the valve body 1; the driving assembly causes the two pistons 5 to slide away from each other, thereby moving the two gates 6 away from each other and pressing against the two valve seats 3, respectively, so that the gates 6 and the valve seats 3 are sealed and the gate is closed. When the drive assembly of this embodiment is used, the extrusion rod 9 slides downward, and the two extrusion bevels 19 respectively fit into the two guide bevels 18. As the extrusion rod 9 moves downward, the extrusion bevels 19 slide downward along the guide bevels 18, thereby pushing the two guide blocks 7 to the left and right sides, causing the two pistons 5 to slide away from each other, and then causing the two gate plates 6 to move away from each other and press the two valve seats 3 respectively, achieving a sealed docking between the gate plates 6 and the valve seats 3, and then achieving sealing of the delivery pipe 10. The extrusion of the extrusion rod 9 causes the two gate plates 6 to move horizontally and be sealed with the valve seats 3 on both sides. In this way, when opening or sealing the delivery pipe opening, the friction between the gate plates 6 and the valve seats 3 is greatly reduced, avoiding wear and making the valve more durable. When the valve is closed, nitrogen is injected into the valve body through the monitoring port 31 on one side to seal the interior of the valve body in all directions. During maintenance, the lower valve cover 2 can be opened to check and replace the seals and remove dust.

[0035] Example 2: like Figure 5 As shown, the difference between this embodiment and embodiment 1 is that the extrusion rod of this embodiment is hollow, and an air intake pipe 21 is fixedly connected to the cavity of the extrusion rod 9. The air intake pipe 21 extends along the length direction of the extrusion rod 9 and passes through the extrusion rod 9. The upper end of the air intake pipe 21 is connected to an external fluid source, and an exhaust pipe 22 is connected to the air intake pipe 21. Switch valves 23 are installed on both the air intake pipe 21 and the exhaust pipe 22.

[0036] Specifically, the external fluid source may be a high-pressure gas tank or a high-pressure liquid tank, and the high-pressure gas or high-pressure liquid is injected into the piston cylinder through the external fluid source.

[0037] Specifically, the intake pipe 21 of this embodiment comprises a straight pipe section extending through the extrusion rod 9 and a flexible hose section connected to the straight pipe section. The flexible hose section is connected to an external fluid source. This connection between the intake pipe and the external fluid source allows the intake pipe 21 to follow the upward and downward movement of the extrusion rod 9 without deformation or damage. In this embodiment, the exhaust pipe 22 is connected to the straight pipe section of the intake pipe 21 via a three-way fitting.

[0038] During use of this embodiment, after the extrusion rod 9 squeezes the two gate plates 6 into sealing engagement with the two valve seats 3, an external fluid source can inject high-pressure fluid into the piston cylinder 4 through the air inlet pipe 21. The high-pressure fluid is then injected between the two pistons 5, further applying pressure to the two gate plates 6, thereby enhancing the sealing effect between the gate plates 6 and the valve seats 3 and improving the sealing performance. When the valve needs to be opened, the on-off valve 23 of the exhaust pipe 22 is opened to discharge the gas, and the extrusion rod 9 is lifted upward. The two gate plates 6 lose their squeezing action and naturally loosen. Driven by the gas in the delivery pipe 10, they are disconnected from the valve seats 3. The valve stem 8 is then lifted upward, causing the piston cylinder 4 to move upward, thereby opening the valve.

[0039] Example 3: The difference between this embodiment and embodiment 2 is that in this embodiment, no outer sealing sleeves 14 are provided at the left and right ends of the piston cylinder 4 .

[0040] like Figure 6 、 7 As shown, in this embodiment, a single-walled bellows 24 is installed between the piston cylinder 4 and the gate plate 6. One end of the single-walled bellows 24 is sealed and fixed to the piston cylinder 4, while the other end of the single-armed bellows 24 is sealed and fixed to the gate plate 6. Specifically, the single-walled bellows 24 comprises a single-layered bellows wall, with sealing rings fixed at both ends. The single-walled bellows 24 is sleeved onto the piston cylinder 4 and bolted to the piston cylinder 4 and gate plate 6 via sealing rings on both sides, facilitating disassembly. When the gate plate 6 moves, the single-walled bellows enhance the sealing effect between the gate plate and the piston cylinder, improving airtightness.

[0041] In this embodiment, a hollow double-walled bellows 25 is provided between the gate plate 6 and the valve seat 3. The double-walled bellows 25 is fixedly connected to the valve seat 3. A vent pipe 26 is fixedly connected to the valve body 1. One end of the vent pipe 26 is connected to the inner cavity of the double-walled bellows 25. The on-off valve 23 is mounted on the vent pipe 26. In this embodiment, two vent pipes 26 are connected to one double-walled bellows 25, one for air intake and one for exhaust, which is more convenient to use.

[0042] Specifically, the double-walled bellows 25 comprises two coaxially arranged inner and outer layers of corrugated pipe walls, forming an annular cavity between the two layers. Sealing rings are secured to both ends of the double-walled bellows walls. During installation, the double-walled bellows 25 is sleeved onto the valve seat 3. The sealing ring on one side of the double-walled bellows 25 is bolted to the valve seat 3, facilitating removal. The sealing ring on the other side of the double-walled bellows 25 faces the sealing gasket 13 of the gate plate 6, allowing for a sealed connection with the sealing ring when the gate plate 6 moves.

[0043] During use of this embodiment, after the gate 6 moves to dock with the valve seat 3, the sealing gasket 13 on the gate 6 and the sealing gasket 13 at the end of the valve seat 3 form a sealed contact, forming a primary seal. Simultaneously, the sealing gasket 13 of the gate 6 also forms a sealed contact with the sealing ring of the double-walled bellows 25, forming a secondary seal. High-pressure fluid is injected into the double-walled bellows 25 through the vent pipe 26, pushing the bellows to expand and contract, tightly fitting the gate 6 and further enhancing the sealing effect.

[0044] Example 4: like Figure 8 、 9As shown, this embodiment differs from Embodiment 1 in that an annular vent cavity 28 is formed between the extrusion rod 9 and the valve stem 8 in this embodiment, and the annular vent cavity 28 is connected to the inner cavity of the piston cylinder 4. The delivery pipe 10 on the inlet side is connected to the annular vent cavity 28 through an air intake pipe 31, and the delivery pipe 10 on the outlet side is connected to the annular vent cavity 28 through an air exhaust pipe 32. Both the air intake pipe 31 and the air exhaust pipe 32 are equipped with an on-off valve 23.

[0045] In this embodiment, the intake pipe 31 and exhaust pipe 32 each include a straight pipe section and a flexible pipe section. The straight pipe section is fixedly connected to the delivery pipe 10. One end of the flexible pipe section is connected to the straight pipe section, and the other end of the flexible pipe section passes through the valve stem 8 and communicates with the annular ventilation cavity 28. The flexible pipe section allows the intake and exhaust pipes to follow the up and down movement of the valve stem without deformation or damage.

[0046] Preferably, due to the cavity between the valve stem 8 and the extrusion rod 9, an annular groove is defined at the lower end of the inner cavity of the valve stem 8 to ensure stability of the extrusion rod 9 as it slides up and down. A guide ring 27 is embedded in the annular groove. The inner diameter of the guide ring 27 matches the outer diameter of the extrusion rod 9. The inner wall of the guide ring 27 is circumferentially defined with multiple ventilation grooves 271. The guide ring 27 guides the upward and downward sliding of the extrusion rod 9, making the sliding more stable. The ventilation grooves 271 on the guide ring are used for ventilation.

[0047] When this embodiment is in use, after the extrusion rod 9 squeezes the two gate plates 6 into sealing contact with the two valve seats 3, the gas in the inlet-side delivery pipe 10 can be fed into the piston cylinder 4 through the air inlet pipe 21 to inject high-pressure fluid. The high-pressure fluid is then injected between the two pistons 5, thereby further applying pressure to the two gate plates 6, thereby improving the sealing effect between the gate plates 6 and the valve seats 3 and enhancing the sealing performance. This embodiment utilizes gas delivered by its own pipeline to improve the sealing effect of the valve, eliminating the need for an external fluid source, saving costs and increasing convenience.

[0048] Example 5: like Figure 10 、 11 As shown, the difference between this embodiment and embodiment 1 is that the drive assembly of this embodiment does not use an extrusion rod.

[0049] The drive assembly of this embodiment comprises two air intake pipes 41 fixedly connected to the valve stem. A partition plate 29 is fixedly connected to the piston cylinder 4, located between the two pistons 5. An air filling chamber is formed between the pistons 5 and the partition plate 29. Both air intake pipes 41 pass through the valve stem 8 and communicate with the two air filling chambers. Each air intake pipe 41 is connected to an external fluid source. Each air intake pipe 41 is connected to an exhaust pipe 42, and both air intake pipes 41 and exhaust pipe 42 are equipped with an on / off valve 23.

[0050] In this embodiment, the intake pipe 41 comprises a straight section extending through the valve stem 8 and a flexible hose section connected to the straight section. The flexible hose section is connected to an external fluid source. This connection allows the intake pipe 41 to follow the vertical movement of the valve stem 8 without deformation or damage. In this embodiment, the exhaust pipe 42 is connected to the straight section of the intake pipe 41 via a three-way fitting.

[0051] When the drive assembly of this embodiment is in use, the partition plate 29 divides the interior of the piston cylinder 4 into two air-filled chambers. An external fluid source, via two air inlet pipes 41, delivers high-pressure fluid to each of the two chambers, applying pressure to the pistons 5, allowing the two pistons 5 to slide independently. Once the two gate plates 6 are sealed against the two valve seats 3, if one piston leaks and is damaged, simply actuating the other piston will restore the valve seal. During maintenance, the damaged piston can be repaired, allowing the valve to function normally even with one piston damaged, resulting in more economical, safer, and more convenient operation.

[0052] Preferably, a hollow rubber tube 30 is provided between the gate plate 6 and the valve seat 3 in this embodiment. The rubber tube 30 is annular and fixedly connected to the valve seat 3. A vent tube 36 is fixedly connected to the valve body 3. One end of the vent tube 36 communicates with the inner cavity of the rubber tube 30. The on-off valve 23 is mounted on the vent tube 36. In this embodiment, two vent tubes 36 are connected to one rubber tube 30, one for air intake and one for exhaust, which is more convenient to use.

[0053] Specifically, the rubber tube 30 is sleeved on the valve seat 3. One side of the rubber tube 30 is fixed to the valve seat 3, and the other side is opposite to the sealing gasket 13 of the gate 6. When the gate 6 moves, it can be sealed and docked with the rubber tube 30.

[0054] When gate 6 moves to dock with valve seat 3, sealing gasket 13 on gate 6 and sealing gasket 13 at the end of valve seat 3 form a primary seal. Simultaneously, sealing gasket 13 on gate 6 also forms a secondary seal with rubber tube 30. High-pressure fluid is injected into rubber tube 30 through vent tube 36, causing it to expand and elastically conform to gate 6, further enhancing the sealing effect.

[0055] Of course, the above description is not limited to the above examples. Technical features not described in the present invention can be achieved by or by adopting existing technologies, which will not be described here. The above embodiments and drawings are only used to illustrate the technical solutions of the present invention and are not limitations of the present invention. The present invention is described in detail with reference to the preferred implementation methods. Ordinary technicians in this field should understand that changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention do not depart from the purpose of the present invention and should also fall within the scope of protection of the claims of the present invention.

Claims

1. A double-movable gate valve for chemical production, comprising a valve body (1), with valve covers (2) fixedly connected to the upper and lower ends of the valve body, characterized in that: The inner wall of the valve body (1) is provided with two valve seats (3) facing each other on the left and right sides. Two delivery pipes (10) corresponding to the two valve seats (3) are fixedly connected to the valve body. A piston cylinder (4) is provided between the two valve seats (3). The left and right ends of the piston cylinder (4) are both slidably connected with pistons (5). The ends of the two pistons (5) away from each other are fixedly connected with gate plates (6). The two gate plates (6) are respectively sealed with the two valve seats (3). A valve stem (8) is fixedly connected to the top of the piston cylinder (4). The upper end of the valve stem passes through the valve cover (2) and extends to the outside. The valve body also includes a drive component for driving the two pistons (5) to slide away from each other along the axial direction of the piston cylinder (4).

2. The double-action gate valve for chemical production according to claim 1, characterized in that: The valve stem (8) is hollow, and the ends of the two pistons (5) that are close to each other are fixed with guide blocks (7), and the sides of the two guide blocks (7) that are close to each other are provided with guide inclined surfaces (18); the driving component is an extrusion rod (9) that is inserted into the valve stem (8) and slides up and down, and the lower end of the extrusion rod (9) passes through the piston cylinder (4) and extends between the two guide blocks (7), and the lower end of the extrusion rod (9) is provided with two extrusion inclined surfaces (19), and the two extrusion inclined surfaces (19) respectively cooperate with the guide inclined surfaces (18) of the two guide blocks (7).

3. The double-action gate valve for chemical production according to claim 2, characterized in that: An air intake pipe (21) is provided in the extrusion rod (9), the air intake pipe (21) extending along the length direction of the extrusion rod (9) and penetrating the extrusion rod (9), the upper end of the air intake pipe (21) being connected to an external fluid source, the air intake pipe being connected to an exhaust pipe (22), and both the air intake pipe and the exhaust pipe being installed with a switch valve (23).

4. The double-action gate valve for chemical production according to claim 2, characterized in that: An annular ventilation cavity (28) is formed between the extrusion rod (9) and the valve stem (8), wherein one delivery pipe (10) is connected to the annular ventilation cavity (28) via an air inlet pipe (31), and the other delivery pipe (10) is connected to the annular ventilation cavity (28) via an air outlet pipe (32), and a switch valve (23) is installed on both the air inlet pipe and the air outlet pipe.

5. The double-action gate valve for chemical production according to claim 4, characterized in that: An annular groove is provided at the lower end of the valve stem (8), and a guide ring (27) is embedded in the annular groove. The inner diameter of the guide ring is adapted to the outer diameter of the extrusion rod (9), and the inner wall of the guide ring (27) is provided with a plurality of ventilation grooves (271) along the circumferential direction.

6. The double-action gate valve for chemical production according to claim 1, characterized in that: A partition plate (29) located between the two pistons (5) is fixedly connected in the piston cylinder (4), and an air-filled cavity is formed between the piston (5) and the partition plate (29). The driving component is two air intake pipes (41) fixedly connected to the valve stem (8). Both air intake pipes pass through the valve stem (8) and are respectively connected to the two air-filled cavities. The two air intake pipes (41) are respectively connected to an external fluid source. The two air intake pipes (41) are respectively connected to an exhaust pipe (42). A switch valve (23) is installed on both the air intake pipe and the exhaust pipe.

7. The double-action gate valve for chemical production according to any one of claims 1 to 6, characterized in that: The left and right ends of the piston cylinder (4) are both fixedly connected with outer sealing sleeves (14), and the two outer sealing sleeves (14) are respectively sleeved on the two gate plates (6).

8. The double-action gate valve for chemical production according to any one of claims 1 to 6, characterized in that: A single-walled bellows (24) is provided between the piston cylinder (4) and the gate plate (6); one end of the single-walled bellows (24) is sealed and fixedly connected to the piston cylinder (4), and the other end of the single-armed bellows is sealed and fixedly connected to the gate plate (6).

9. The double-action gate valve for chemical production according to claim 8, characterized in that: A hollow double-walled corrugated pipe (25) is provided between the gate plate (6) and the valve seat (3). The double-walled corrugated pipe (25) is fixedly connected to the valve seat (3). A vent pipe (26) is fixedly connected to the valve body. One end of the vent pipe (26) is communicated with the inner cavity of the double-walled corrugated pipe (25). An on-off valve (23) is installed on the vent pipe (26).

10. The double-action gate valve for chemical production according to claim 8, characterized in that: A hollow rubber tube (30) is provided between the gate plate (6) and the valve seat (3). The rubber tube (30) is annular and fixed to the valve seat (3). A vent tube (36) is fixed to the valve body. One end of the vent tube (36) is in communication with the inner cavity of the rubber tube (30). An on-off valve (23) is installed on the vent tube (36).

11. The method for using a double-action gate valve for chemical production according to any one of claims 1 to 6, 9, and 10, characterized in that: The following steps are involved: The valve stem (8) slides downward, causing the piston cylinder (4) to contact the limit column (12), and the gate plates (6) on both sides of the piston cylinder (4) to face the valve seats (3) on both sides of the valve body (1); the two pistons (5) are driven to slide away from each other, thereby causing the two gate plates (6) to move away from each other and respectively press the two valve seats (3), so that the gate plates (6) and the valve seats (3) are sealed and docked, and the gate is closed.

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