A double-disc flat gate valve capable of preventing explosion of middle cavity overpressure

Abstract

This invention relates to the field of double-gate flat gate valve technology. Addressing the pain points of existing valves, such as severe wear of the sealing surfaces during opening and closing, the risk of explosion due to overpressure in the central cavity, and the poor applicability of existing pressure relief solutions, this invention provides a double-gate flat gate valve that prevents explosion due to overpressure in the central cavity. The invention features an adjustable sealing pressure regulating device at the lower end of the valve stem, and the gate assembly is equipped with an elastic telescopic pull rod. The gate assembly employs a top block and push block with inclined plane transmission, combined with a telescopic cylindrical sleeve structure. When closing, the left gate first seals the inlet cavity, and the residual medium in the central cavity is automatically emptied through the outlet cavity before the right gate seals the outlet cavity, eliminating the need for an additional pressure relief valve. This invention effectively reduces wear on the sealing surfaces, completely avoids the risk of overpressure in the central cavity, and is suitable for high-pressure, high-temperature, and highly toxic / flammable / explosive media conditions, significantly improving valve life and operational safety.

Description

Technical Field

[0001] This invention relates to the field of valve technology, specifically to a double-gate flat plate gate valve designed to prevent explosion due to overpressure in the central cavity. The invention aims to solve the technical problems of severe wear of the sealing pair during opening and closing of existing double-gate flat plate gate valves, easy explosion caused by overpressure in the central cavity, and poor applicability of existing pressure relief solutions. Background Technology

[0002] A double-gate flat gate valve refers to a valve body composed of two gates and two valve seats forming two sets of sealing surfaces. This allows it to withstand very high media pressure. When used in high-pressure, high-temperature, and high-flow pipelines, it offers excellent sealing performance. However, it also has some technical drawbacks. These include: to maintain sufficient sealing pressure on the sealing surface, the sealing surfaces between the gate and valve seats experience significant friction during valve opening and closing, making them prone to damage; and when the valve is closed, media remains in the cavity, which is affected by external temperature, causing thermal expansion and contraction. Especially under high-temperature conditions such as fires, the media in the cavity expands due to high temperatures, potentially leading to valve rupture.

[0003] Some existing double-gate flat plate gate valves have a pressure relief valve installed in the cavity. When the medium in the cavity generates high pressure, it is discharged through the pressure relief valve. However, this increases costs, and it is not suitable for directly discharging highly toxic or corrosive media to the outside environment. Other solutions without a pressure relief valve achieve pressure relief in the cavity by optimizing the gate structure, but these solutions suffer from problems such as complex structure, inconvenient adjustment of sealing pressure, and unstable pressure relief reliability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a double-gate flat plate gate valve that is protected against overpressure explosion in the cavity.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A double-gate flat gate valve with anti-overpressure explosion protection in the central cavity includes a valve body, a valve cover, a valve stem, and a driving device. The valve body is provided with an inlet chamber, an outlet chamber, a gate assembly, and left and right valve seats. The valve cover is located on the upper end of the valve body, and a central cavity is formed between the valve cover and the valve body. The valve stem passes through the valve cover, and the upper end of the valve stem is connected to the driving device. The valve stem is characterized by: an adjusting device at its lower end; a pull rod at the upper end of the gate assembly, which is elastically extendable and retractable within the adjusting device; and the gate assembly includes left and right gates, each with opposing left and right cylinders, which are respectively extendable and retractable within the cylinders. The cylindrical sleeve has a left push block, a left top block, a right top block, and a right push block sequentially mounted on both ends. There is a vertical movement gap between the left and right top blocks and the cylindrical sleeve. A left inclined surface is provided between the left top block and the left push block for driving engagement, with the left push block fitting against the left gate plate. A right inclined surface is provided between the right top block and the right push block for driving engagement, with the right push block fitting against the right gate plate. The upper end of the left top block is connected to the lower end of the pull rod. The upper end of the left push block has a left pull head, and the upper end of the right top block has a right pull head. The lower ends of the left and right pull heads are respectively driven to the upper end of the left top block. The upper end of the right pull head is driven to the lower end of the adjusting device. The lower end of the left top block is connected to a lower valve stem. A lower positioning hole is provided at the bottom of the valve body corresponding to the lower valve stem. The bottom of the valve body also has a lower limit structure for the left and right push blocks.

[0006] Preferably, the adjusting device includes an adjusting sleeve, a pull sleeve, a pull head, an adjusting block, and a crossbar. The upper end of the pull sleeve is connected to the lower end of the valve stem. The adjusting block is movable up and down inside the pull sleeve, and the crossbar passes through the adjusting block. The corresponding pull sleeve has a vertical groove. The adjusting sleeve is threaded to the upper end of the pull sleeve, and the adjusting sleeve forms the upper limit position of the adjusting block. The upper end of the pull rod extends into the pull sleeve, and a spring is provided between the pull rod and the adjusting block. The pull head is located at the lower end of the pull sleeve, and the pull head forms the lower limit position of the pull rod. The lower end of the pull sleeve is in transmission cooperation with the upper end of the right pull head.

[0007] Preferably, the upper end of the pull rod is a T-shaped head, which extends into and is confined within the pull sleeve.

[0008] Preferably, the outer side of the left top block is provided with an anti-rotation rod, and the corresponding inner wall of the valve body is provided with an anti-rotation groove, with the anti-rotation rod cooperating with the anti-rotation groove.

[0009] Preferably, the drive device is mounted on the upper end of the valve cover via a bracket, and a packing is provided between the upper end of the valve cover and the valve stem. The packing is equipped with a pressure cap, and the pressure cap and the bracket are fixed together to the upper end of the valve cover.

[0010] Preferably, the left cylinder is integrally formed at the center of the inner side of the left gate plate, and the right cylinder is integrally formed at the center of the inner side of the right gate plate.

[0011] Preferably, the left and right inclined surfaces are arranged opposite each other, and both are upward inclined surfaces.

[0012] Preferably, the lower limit structures of the left and right push blocks are a left lower limit block and a right lower limit block, respectively, with the left lower limit block cooperating with the left push block and the right lower limit block cooperating with the right push block.

[0013] The beneficial effects of this invention are as follows: the improved anti-overpressure explosion double-gate flat gate valve has the following advantages: During the opening process, the left and right top blocks reduce the lateral thrust of the left and right push blocks on the left and right gates, respectively, thereby reducing the sealing pressure of the sealing pairs between the left and right gates and the left and right valve seats. This results in less friction on the sealing pairs between the gates and the valve seats, less wear on the sealing pairs, and a longer service life. During the closing process, the left gate first presses against the left valve seat with the cooperation of the left top block and the left push block, forming a seal between the left gate and the left valve seat. Then, the medium in the middle cavity is discharged sequentially through the gap between the right gate and the right valve seat and the outlet. Next, with the cooperation of the right top block and the right push block, the right gate presses against the right valve seat and forms a seal. The medium will not remain in the middle cavity, preventing the valve from bursting and ensuring high safety. Attached Figure Description

[0014] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0015] Figure 1 This is a schematic diagram of the valve in the closed state according to the present invention.

[0016] Figure 2 This is a schematic diagram of the valve in the open state according to the present invention.

[0017] Figure 3 This is a schematic diagram of the adjustment device structure of the present invention. Detailed Implementation

[0018] The accompanying drawings illustrate the structure of the invention, and further details will be described below in conjunction with the drawings. In this embodiment, the components included in the drawings... Figure 1-3 The anti-overpressure explosion double-gate flat gate valve includes a valve body 1, a valve cover 10, a valve stem 11, and a drive device 13. The valve body 1 is provided with an inlet chamber 2, an outlet chamber 21, a gate assembly 3, and left and right valve seats 4 and 22. The left valve seat 4 is located on the side of the inlet chamber 2, and the right valve seat 22 is located on the side of the outlet chamber 21. The valve cover 10 is detachable and sealed on the upper end of the valve body 1, and a cavity 16 is formed between the valve cover 10 and the valve body 1. The valve stem 11 is movable and sealed through the valve cover 10. The upper end of the valve stem 11 is connected to the drive device 13. The drive device 13 is an existing structure, specifically including a motor and its gear transmission components and a drive handwheel. The drive device 13 is installed on the upper end of the valve cover 10 through a bracket 12. A packing 15 is provided between the upper end of the valve cover 10 and the valve stem 11. The packing 15 is equipped with a pressure cap 14. The pressure cap 14 and the bracket 12 are fixed to the upper end of the valve cover 10 by bolts.

[0019] The lower end of the valve stem 11 is provided with an adjustment device, and the upper end of the gate assembly 3 is provided with a pull rod 6, which is elastically telescopically disposed within the adjustment device. The gate assembly 3 includes left and right gates 26 and 34, on which are provided opposing left and right cylinders 30 and 37. Preferably, the left cylinder 30 is integrally formed at the center of the inner side of the left gate 26, and the right cylinder 37 is integrally formed at the center of the inner side of the right gate 34. The left and right cylinders 30 and 37 are telescopically disposed at both ends of the cylindrical sleeve 29, and a left push block 2 is sequentially sleeved on the cylindrical sleeve 29. 7. Left top block 31, right top block 35, right push block 36. The left and right top blocks 31 and 35 are provided with vertical movement gaps between themselves and the cylindrical sleeve 29. The left top block 31 and the left push block 27 are provided with a left inclined surface 28 for driving cooperation. The left push block 27 is attached to the left gate plate 26. The right top block 35 and the right push block 36 are provided with a right inclined surface 38 for driving cooperation. The right push block 36 is attached to the right gate plate 34. The left inclined surface 28 and the right inclined surface 38 are arranged opposite to each other and are both upward inclined surfaces. That is, when the left top block 31 moves down, it drives the left push block 27 to move to the left. When the right top block 35 moves down, it drives the right push block 36 to move to the right.

[0020] The upper end of the left top block 31 is connected to the lower end of the pull rod 6. The upper end of the left push block 27 is provided with a left pull head 32, and the upper end of the right top block 35 is provided with a right pull head 33. The lower ends of the left and right pull heads 32 and 33 are respectively driven to the upper end of the left top block 31. The upper end of the right pull head 33 is driven to the lower end of the adjusting device. The lower end of the left top block 31 is connected to a lower valve rod 39. The bottom of the valve body 1 corresponding to the lower valve rod 39 is provided with a lower positioning hole 24. The bottom of the valve body 1 is also provided with the lower limit of the left and right push blocks 27 and 36. The lower limit structures of the left and right push blocks 27 and 36 are the left lower limit block 25 and the right lower limit block 23, respectively. The left lower limit block 25 is in a limiting cooperation with the left push block 27, and the right lower limit block 23 is in a limiting cooperation with the right push block 36. That is, after the left push block 27 moves down to its position, it is limited by the left lower limit block 25. At this time, the left gate plate 26 corresponds to the left valve seat 4. After the right push block 36 moves down to its position, it is limited by the right lower limit block 23. At this time, the right gate plate 34 corresponds to the right valve seat 22.

[0021] As a further improved specific implementation, the adjusting device includes an adjusting sleeve 9, a pull sleeve 8, a pull head 5, an adjusting block 19, and a crossbar 18. The upper end of the pull sleeve 8 is connected to the lower end of the valve stem 11. The adjusting block 19 is movable up and down and is disposed inside the pull sleeve 8. The crossbar 18 passes through the adjusting block 19. The corresponding pull sleeve 8 is provided with a vertical groove 17. The adjusting sleeve 9 is threaded to the upper end of the pull sleeve 8 and forms the upper limit position of the adjusting block 19. The upper end of the pull rod 6 extends into the pull sleeve 8. A spring 7 is provided between the pull rod 6 and the adjusting block 19. The pull head 5 is disposed at the lower end of the pull sleeve 8 and forms the lower limit position of the pull rod 6. The lower end of the pull sleeve 8 is in transmission cooperation with the upper end of the right pull head 33. Preferably, the upper end of the pull rod 6 is a T-shaped head. The T-shaped head extends into and is confined within the pull sleeve 8 to realize the confinement of the pull rod 6 within the pull sleeve 8 and to facilitate the installation of the spring 7.

[0022] As a further improved specific implementation, an anti-rotation rod (not shown in the figure) is provided on the outer side of the left top block 31, and an anti-rotation groove 40 is provided on the inner wall of the corresponding valve body 1. The anti-rotation rod cooperates with the anti-rotation groove 40. During the lifting and lowering process of the gate assembly 3, the anti-rotation rod slides up and down along the anti-rotation groove 40 to prevent the gate assembly 3 from rotating around the axis of the valve stem 11.

[0023] Working principle of the invention:

[0024] Closing process: The drive device 13 moves the valve stem 11 downward. Since the valve stem 11 is connected to the adjustment device, and the adjustment device is connected to the gate assembly 3 through the pull rod 6, it moves the gate assembly 3 downward together. When the lower parts of the left and right push blocks 27 and 36 contact the left and right lower limit blocks 25 and 23 respectively, the gate assembly 3 stops moving downward. At this time, the lower part of the lower valve stem 39 extends into the lower positioning hole 24. The drive device 13 continues to move the valve stem 11 downward. The left top block 31 continues to move downward under the push of the pull rod 6. Since the left top block 31 and the left push block 27 form an inclined contact, the left top block 31 pushes the left push block 27 and the left gate 26 to the left. The left gate 26... The left valve seat 4 is pressed and a seal is formed. The drive device 13 continues to drive the valve stem 11 to move downward. Since the pull rod 6 can no longer push the left top block 31 downward, when the valve stem 11 drives the adjustment device downward, the pull head 5 disengages from the upper part of the pull rod 6 and moves downward together with the adjustment device. The spring 7 is compressed. As the valve stem 11 and the adjustment device continue to move downward, the lower end face of the pull sleeve 8 presses against the upper end face of the right top block 35 and pushes the right top block 35 downward. Since the right top block 35 and the right push block 36 form an inclined contact, the right top block 35 pushes the right push block 36 and the right gate plate 34 to the right. The right gate plate 34 presses against the right valve seat 22 and forms a seal. At this time, the valve is completely closed.

[0025] Since the seal between the right gate 34 and the right valve seat 22 is later than the seal between the left gate 26 and the left valve seat 4, the residual medium in the middle cavity 16 is discharged through the gap between the right gate 34 and the right valve seat 22 → outlet cavity 21 → system pipeline, thus completely eliminating the residue of the medium.

[0026] During the entire closing process, no excessive moving friction is generated between the left gate 26 and the left valve seat 4, and no excessive moving friction is generated between the right gate 34 and the right valve seat 22. Therefore, the sealing surface wear is small and the service life is long.

[0027] Opening process: The drive device 13 drives the valve stem 11 to move upward. Since the valve stem 11 is connected to the adjustment device, it drives the adjustment device to move upward. The lower end face of the pull sleeve 8 disengages from the upper end face of the right top block 35. The force exerted by the right top block 35 on the right push block 36 and the right gate plate 34 pressing against the right valve seat 22 disappears. There is no longer a mutual pressing force between the right gate plate 34 and the right valve seat 22. The adjustment device continues to move upward. The upper end of the pull head 5 contacts the upper part of the pull rod 6. The pull rod 6 and the left top block 31 move upward together with the adjustment device. The force exerted by the left top block 31 on the left push block 27 and the left gate plate 26 pressing against the left valve seat 4 disappears. There is no longer a mutual pressing force between the left gate plate 26 and the left valve seat 4. As the drive device 13 continues to drive the valve stem 11 to move upward and the adjustment device to move upward, the gate assembly 3 moves upward together with the adjustment device, and the valve opens.

[0028] During the entire opening process, no excessive moving friction is generated between the left gate 26 and the left valve seat 4, and no excessive moving friction is generated between the right gate 34 and the right valve seat 22. Therefore, the sealing surface wear is small and the service life is long.

[0029] The function of the adjusting device: The adjusting sleeve 9 is connected to the pull sleeve 8 via a thread and is placed on the upper part of the pull sleeve 8. By rotating the adjusting sleeve 9, the horizontal bar 18 and the adjusting block 19 are controlled to move up and down, thereby controlling the pre-compression of the spring 7. During the closing process, the valve stem 11 drives the pull sleeve 8, adjusting sleeve 9, horizontal bar 18 and adjusting block 19 to move down. Under the action of the spring 7, the pull rod 6 is pushed down together. When the lower ends of the left and right push blocks 27 and 36 contact the left and right lower limit blocks 25 and 23 respectively, the pull rod 6 and the gate assembly 3 stop moving down. At this time, the valve stem 11 continues to move down. When the adjusting device moves downward, the spring 7 continues to compress under the action of the crossbar 18 and the adjusting block 19. The downward force of the spring 7 on the pull rod 6 increases, which means that the force of the left top block 31 pushing the left push block 27 and the left gate plate 26 to the left increases. The sealing pressure between the left gate plate 26 and the left valve seat 4 increases. Therefore, by controlling the pre-compression of the spring 7, the sealing pressure between the left gate plate 26 and the left valve seat 4 can be adjusted to prevent the sealing surface from being damaged when the sealing pressure is too high, and to prevent the sealing function from being ineffective when the sealing pressure is too low.

[0030] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A double-gate flat gate valve for preventing overpressure explosion in the central cavity, comprising a valve body, a valve cover, a valve stem, and a drive device, wherein the valve body is provided with an inlet chamber, an outlet chamber, a gate assembly, and left and right valve seats; the valve cover is disposed on the upper end of the valve body, and a central cavity is formed between the valve cover and the valve body; the valve stem passes through the valve cover, and the upper end of the valve stem is connected to the drive device for transmission; characterized in that: The lower end of the valve stem is provided with an adjusting device, and the upper end of the gate assembly is provided with a pull rod, which is elastically telescopically mounted within the adjusting device. The gate assembly includes left and right gates, each with opposing left and right cylinders. The left and right cylinders are telescopically mounted at both ends of a cylindrical sleeve. A left push block, a left top block, a right top block, and a right push block are sequentially mounted on the cylindrical sleeve. A vertical movement clearance is provided between the left and right top blocks and the cylindrical sleeve. A left inclined surface is provided between the left top block and the left push block for driving engagement, with the left push block fitting against the left gate. A right inclined surface is provided between the right top block and the right push block for driving engagement, with the right push block fitting against the right gate. The upper end of the left top block is connected to the lower end of the pull rod. The upper end of the left push block is provided with a left pull head, and the upper end of the right top block is provided with a right pull head. The lower ends of the left and right pull heads are respectively driven to the upper end of the left top block, and the upper end of the right pull head is driven to the lower end of the adjusting device. The valve body is connected to a lower valve stem, and a lower positioning hole is provided at the bottom of the valve body corresponding to the lower valve stem. The bottom of the valve body is also provided with a lower limit structure for left and right push blocks. The adjustment device includes an adjustment sleeve, a pull sleeve, a pull head, an adjustment block, and a crossbar. The upper end of the pull sleeve is connected to the lower end of the valve stem. The adjustment block is movable up and down and is set inside the pull sleeve. The crossbar passes through the adjustment block. The pull sleeve is provided with a vertical groove. The adjustment sleeve is threaded to the upper end of the pull sleeve and forms the upper limit of the adjustment block. The upper end of the pull rod extends into the pull sleeve. A spring is provided between the pull rod and the adjustment block. The pull head is set at the lower end of the pull sleeve and forms the lower limit of the pull rod. The lower end of the pull sleeve is driven to cooperate with the upper end of the right pull head. During the closing process, the valve stem moves down, and the pull rod, the left top block, and the left push block are driven in sequence to drive the left gate to close in advance. The valve stem continues to move down, and the adjustment device, the right top block, and the right push block are driven in sequence to drive the right gate to close.

2. The double-gate flat plate gate valve for preventing overpressure explosion in the central cavity as described in claim 1, characterized in that: The upper end of the pull rod is a T-shaped head, which extends into and is confined within the pull sleeve.

3. The double-gate flat plate gate valve for preventing overpressure explosion in the central cavity as described in claim 1, characterized in that: An anti-rotation rod is provided on the outer side of the left top block, and an anti-rotation groove is provided on the inner wall of the corresponding valve body. The anti-rotation rod and the anti-rotation groove cooperate with each other.

4. The double-gate flat plate gate valve for preventing overpressure explosion in the central cavity as described in claim 1, characterized in that: The drive device is mounted on the upper end of the valve cover via a bracket. A packing material is provided between the upper end of the valve cover and the valve stem. The packing material is equipped with a pressure cap. The pressure cap and the bracket are fixed together to the upper end of the valve cover.

5. The anti-overpressure explosion double-gate flat gate valve as described in claim 1, characterized in that: The left cylinder is integrally formed at the center of the inner side of the left gate plate, and the right cylinder is integrally formed at the center of the inner side of the right gate plate.

6. The double-gate flat plate gate valve for preventing overpressure explosion in the central cavity as described in claim 1, characterized in that: The left and right inclined surfaces are arranged opposite each other, and both are upward inclined surfaces.

7. The double-gate flat plate gate valve for preventing overpressure explosion in the central cavity as described in claim 1, characterized in that: The lower limit structures of the left and right push blocks are a left lower limit block and a right lower limit block, respectively. The left lower limit block is in a limiting cooperation with the left push block, and the right lower limit block is in a limiting cooperation with the right push block.

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