High-temperature high-pressure parallel double-disc gate valve and opening and closing method thereof

Abstract

The invention relates to a high-temperature and high-pressure parallel double-disc gate valve and an opening and closing method thereof, and relates to the field of valves. According to the technical scheme, the baffle-free design is adopted, the left flashboard and the right flashboard are clamped through the protruding steps on the two sides of the pull ring to be prevented from being disengaged, a traditional welding baffle structure is abandoned, and the welding procedure is omitted to reduce the production cost; the pull ring is installed in the bottom groove of the T-shaped groove of the connecting block, the lower end of the valve rod is used for pressing and limiting, fastening screws are abandoned for fixing, and the safety risk that the screws fall into a valve cavity is eradicated. The connecting block is installed in an open mode, the valve rod is installed from the side of the T-shaped groove, the time-consuming valve rod sleeving and threaded connection procedures are abandoned, the assembling efficiency is improved, and internal parts are convenient to replace. The left flashboard and the right flashboard are installed on two sides of the connecting block, connected with the spring in a pressing mode and arranged between the left valve seat and the right valve seat, the spring provides initial sealing force, the valve can be effectively prevented from being jammed or stuck under the high-temperature working condition, and smooth operation is guaranteed. In addition, the circular flashboard can rotate freely during action, so that a sealing surface is worn uniformly, and the service life of the valve is prolonged.

Description

Technical Field

[0001] This invention relates to the field of valve technology, and in particular to a high-temperature and high-pressure parallel double gate valve and its opening and closing method. Background Technology

[0002] In high-temperature and high-pressure equipment in industries such as petroleum, chemical, and metallurgy, the extreme environment of high temperature and high pressure can easily cause valves to malfunction, such as sticking or jamming. Such malfunctions can directly force the entire set of equipment to shut down for maintenance, which not only affects the production schedule but also causes considerable direct economic losses to the enterprise.

[0003] Furthermore, valves operating under these conditions are often installed in hazardous areas such as high-temperature and high-pressure environments. Due to the limitations of the working environment, maintenance personnel cannot conduct real-time inspections and troubleshooting of their operation at close range, making it difficult to detect potential valve failures in advance and address them promptly. Once a valve fails, the entire system must be forced to shut down before the faulty valve can be repaired or replaced. This not only further increases economic losses but also results in a significant waste of time, severely impacting the continuity and stability of production. Summary of the Invention

[0004] The purpose of this invention is to provide a high-temperature and high-pressure parallel double-gate valve and its opening and closing method to solve the problems existing in the prior art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a high-temperature and high-pressure parallel double-gate valve, comprising a valve body, wherein the high-temperature and high-pressure parallel double-gate valve further comprises: The valve seat assembly includes a left valve seat and a right valve seat, which are respectively installed in the preset seat cavity of the valve body; A gate assembly, comprising a left gate and a right gate, symmetrically arranged between the left valve seat and the right valve seat, for adapting to the valve seat assembly to achieve a seal; A connecting transmission assembly includes a connecting block, a spring, a pull ring, and a valve stem. The connecting block is embedded between the left gate and the right gate. The spring is mounted on the connecting block. The pull ring is connected to the connecting block, the left gate, and the right gate respectively. The valve stem is correspondingly connected to the pull ring and passes through the upper cover assembly to transmit opening and closing power. An upper cover assembly includes an upper cover, a cover plate, a stud I, and a nut I. The upper cover is installed at the head of the valve body, the cover plate covers the upper end of the valve body's central cavity, and the stud I and the nut I are threadedly connected to achieve the connection between the cover plate and the upper cover. A sealing packing assembly is assembled inside a pre-set stuffing box in the upper cover to achieve a dynamic seal between the valve stem and the upper cover, preventing media leakage.

[0006] In some embodiments, the cover assembly further includes: A sealing ring is fitted between the mating surfaces of the upper cover and the valve body; A pressure ring, which is stacked on top of the sealing ring; and The four-ring seal is mounted above the pressure ring and inserted into the pre-set central cavity groove of the valve body to press the sealing ring, thereby improving the sealing performance between the upper cover and the valve body and preventing media leakage.

[0007] In some embodiments, the stud I passes through a pre-set mounting hole in the cover plate, the lower end of the stud I is screwed into a corresponding threaded hole in the upper cover, and the nut I is tightened to the upper end of the stud I and fits against the upper surface of the cover plate. The tension generated by tightening the nut I causes the upper cover to move upward, thereby pressing the sealing ring and enhancing the sealing reliability.

[0008] In some embodiments, the sealing packing assembly includes: The guide sleeve, packing gasket, packing assembly, and packing gland are assembled sequentially from bottom to top within the stuffing box of the upper cover.

[0009] In some embodiments, the sealing packing assembly further includes: A packing pressure plate, stacked on the packing gland, has a stud II passing through a pre-drilled bolt hole in the packing pressure plate, the lower end of which is screwed into a corresponding threaded hole in the upper cover; and A disc spring assembly is fitted onto the stud II and located between the packing pressure plate and the nut II. The nut II is tightened onto the upper end of the stud II to press the disc spring assembly. The elastic force of the disc spring assembly is transmitted to the packing gland through the packing pressure plate, thereby pressing the packing assembly to ensure a sealing effect.

[0010] In some embodiments, both the left and right valve seats are fixed to the seat cavity of the valve body by welding, and the left and right valve seats form an integrated structure with the valve body, which effectively improves the connection strength and sealing stability under high temperature and high pressure conditions.

[0011] In some embodiments, the connecting block has a through hole adapted to the spring, and the spring is fitted into the through hole.

[0012] In some embodiments, the left gate and the right gate are respectively fitted and assembled on the left and right sides of the connecting block, and the left gate and the right gate are respectively abutted against the spring, so as to provide the initial sealing preload force to the left gate and the right gate through the elastic force of the spring.

[0013] In some embodiments, the bottom of the T-slot of the connecting block is provided with a groove for adapting to the pull ring, the pull ring is embedded in the groove, and the two sides of the pull ring are provided with raised steps, which are respectively engaged and adapted to the left gate and the right gate to limit the left gate and the right gate.

[0014] In some embodiments, the lower end of the valve stem is fitted into the top of the T-slot of the connecting block from the side of the T-slot, and the lower end of the valve stem abuts and presses against the pull ring to limit and fix the pull ring, preventing the pull ring from coming out of the groove of the connecting block.

[0015] In some embodiments, the left gate and the right gate have circular outlines. During the valve opening and closing process, the left gate and the right gate can rotate freely relative to the valve seat assembly, so that the gate sealing surface wears evenly and effectively extends the overall service life of the valve.

[0016] In some embodiments, the packing assembly is composed of multiple sets of graphite packing rings stacked together, with a metal spacer ring between adjacent sets of graphite packing rings. The metal spacer ring is made of stainless steel and is used to enhance the structural stability of the packing assembly and prevent the packing rings from deforming or failing under high temperature and high pressure.

[0017] In some embodiments, the sealing ring is made of flexible graphite wound with metal, and its cross-section is trapezoidal, which is used to improve the fit between the sealing ring and the mating surfaces of the upper cover and the valve body, thereby enhancing the sealing performance.

[0018] In some embodiments, the mating sealing surfaces of the left gate, the right gate, the left valve seat, and the right valve seat are all provided with a wear-resistant and high-temperature resistant coating. The coating is made of a nickel-based alloy and is used to improve the wear resistance and high-temperature resistance of the sealing surfaces.

[0019] Secondly, the present invention provides a method for opening and closing a high-temperature and high-pressure parallel double-gate valve, the method being applied to the aforementioned high-temperature and high-pressure parallel double-gate valve, the method comprising: When the valve is closed, the left and right gates fit against the left and right valve seats fixed in the valve body cavity. At this time, the spring in the connecting block through hole provides a continuous initial sealing preload, ensuring that the gates and valve seats fit tightly and preventing media leakage. At the same time, the circular structure of the left and right gates can rotate freely relative to the left and right valve seats during the fitting process, so that the sealing surfaces of the gates and valve seats are worn evenly. At this time, the sealing ring between the upper cover and the valve body, together with the pressure ring and the four-open ring, further blocks the media leakage channel, and achieves double sealing with the sealing packing assembly. When the valve is opened, the valve stem moves the connecting block, the left gate, and the right gate upwards as a whole, separating the gate from the valve seat, allowing the medium to flow smoothly through the internal channel of the valve body. During the up-and-down movement of the valve stem, the sealing packing assembly in the stuffing box of the upper cover plays its role, and the elastic force of the disc spring assembly is transmitted to the packing gland through the packing pressure plate, pressing the packing assembly to achieve a dynamic seal between the valve stem and the upper cover, preventing the medium from leaking along the valve stem.

[0020] The beneficial effects of the technical solution provided by this invention include at least the following: This technical solution adopts a baffle-less design, using raised steps on both sides of the pull ring to hold the left and right gate plates in place, effectively preventing the gate plates from detaching. It also eliminates the traditional welded baffle structure, removing the welding process and reducing production costs. The pull ring is installed in the groove at the bottom of the T-slot of the connecting block, using the lower end of the valve stem to press the pull ring for limiting and fixing, eliminating the need for fastening screws and preventing the safety risk of fastening screws falling into the valve cavity during valve use. The connecting block adopts an open installation structure, with the valve stem inserted from the side of the T-slot, eliminating time-consuming processes such as valve stem assembly and threaded connections, significantly reducing costs. It improves assembly efficiency and makes internal parts replacement convenient and quick; the left and right gates are respectively installed on the left and right sides of the connecting block and pressed onto the spring, placed between the left and right valve seats. The spring provides initial sealing force, which can effectively prevent valve movement from jamming or getting stuck under high temperature conditions, ensuring smooth valve operation; at the same time, the left and right gates are designed with a circular outline, which can rotate freely during valve operation, so that the sealing surface wears evenly, effectively extending the service life of the valve. Overall, it realizes safe, stable and efficient valve operation, which has significant practical and economic advantages compared with existing technologies. Attached Figure Description

[0021] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0022] Figure 1 A schematic diagram of the structure of a high-temperature and high-pressure parallel double gate valve provided in an exemplary embodiment of the present invention is shown.

[0023] Figure 2 A partial structural schematic diagram of the valve seat assembly and gate assembly of a high-temperature and high-pressure parallel double gate valve provided in an exemplary embodiment of the present invention is shown.

[0024] Figure 3 A partial structural isometric view of the valve seat assembly and gate assembly of a high-temperature and high-pressure parallel double gate valve provided in an exemplary embodiment of the present invention is shown.

[0025] In the picture: 1. Valve body; 2. Right valve seat; 3. Right gate; 4. Connecting block; 5. Spring; 6. Left gate; 7. Left valve seat; 8. Pull ring; 9. Valve stem; 10. Top cover; 11. Sealing ring; 12. Pressing ring; 13. Four open loops; 14. Cover plate; 15. Nut I; 16. Stud I; 17. Guide sleeve; 18. Packing pad; 19. Packing assembly; 20. Packing gland; 21. Packing pressure plate; 22. Disc spring assembly; 23. Nut II; 24. Stud II. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In this specification, identical components are represented by the same reference numerals. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, while the terms "bottom surface," "top surface," "inner," and "outer" refer to directions towards or away from a specific component. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this specification, "multiple" means two or more.

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Please see Figures 1 to 3 A high-temperature and high-pressure parallel double-gate valve includes a valve body 1; a valve seat assembly including a left valve seat 7 and a right valve seat 2, which are respectively installed in a preset seat cavity of the valve body 1; a gate assembly including a left gate 6 and a right gate 3, which are symmetrically arranged between the left valve seat 7 and the right valve seat 2 for fitting with the valve seat assembly to achieve sealing; and a connecting transmission assembly including a connecting block 4, a spring 5, a pull ring 8, and a valve stem 9. The connecting block 4 is embedded between the left gate 6 and the right gate 3, the spring 5 is assembled on the connecting block 4, and the pull ring 8 is connected to the connecting block 4, the left gate 6, and the right gate 3 respectively. The right gate 3 is connected to the valve stem 9, which is correspondingly connected to the pull ring 8 and passes through the upper cover assembly to transmit the opening and closing power. The upper cover assembly includes an upper cover 10, a cover plate 14, a stud I16, and a nut I15. The upper cover 10 is installed at the middle head position of the valve body 1, the cover plate 14 is installed on the upper end of the middle cavity of the valve body 1, and the stud I16 and the nut I15 are threadedly connected to realize the connection between the cover plate 14 and the upper cover 10. The sealing packing assembly is assembled in the pre-set stuffing box of the upper cover 10 to realize the dynamic sealing between the valve stem 9 and the upper cover 10 to prevent media leakage.

[0030] In this embodiment, the valve seat assembly and the gate assembly cooperate to block media leakage and ensure reliable sealing. The connecting transmission assembly transmits the opening and closing power. All components work together to ensure smooth and synchronous gate movement, while also limiting and fixing the gate to prevent components from falling off. The top cover assembly provides sealing protection for internal components and is secured with fasteners, enhancing overall structural stability. The sealing packing assembly is assembled within a pre-set stuffing box in the top cover 10, specifically addressing gap leakage during valve stem 9 movement, achieving dynamic sealing, and ensuring safe and stable valve operation under extreme conditions.

[0031] In some embodiments, please refer to Figure 1The upper cover assembly also includes: a sealing ring 11, which is fitted between the mating surfaces of the upper cover 10 and the valve body 1; a pressure ring 12, which is stacked on top of the sealing ring 11; and a four-ring 13, which is fitted on top of the pressure ring 12 and snaps into the pre-set central cavity annular groove of the valve body 1, for pressing the sealing ring 11 to improve the sealing performance between the upper cover 10 and the valve body 1 and prevent media leakage. A stud I16 passes through a pre-set mounting hole in the cover plate 14, and the lower end of the stud I16 is screwed into the corresponding threaded hole in the upper cover 10. A nut I15 is tightened on the upper end of the stud I16 and fits against the upper surface of the cover plate 14. The tension generated by tightening the nut I15 causes the upper cover 10 to move upward to press the sealing ring 11 and enhance the sealing reliability.

[0032] In one example, the sealing ring 11 is made of flexible graphite wound with metal, and its cross-section is trapezoidal to improve the fit between the sealing ring 11 and the mating surfaces of the upper cover 10 and the valve body 1, thereby enhancing the sealing performance.

[0033] In this embodiment, the sealing ring 11 fills the gap between the upper cover 10 and the valve body 1, blocking the medium leakage channel. The pressure ring 12 bears the force of the four-ring 13, evenly transmitting pressure to the sealing ring 11 and preventing uneven force on the sealing ring 11 from causing failure. The four-ring 13 is inserted into the annular groove in the middle cavity of the valve body 1 to achieve limiting and fixing, providing stable support for the pressure ring 12 and ensuring continuous compression of the sealing ring 11. The stud I16 and nut I15 cooperate to achieve a firm connection between the cover plate 14 and the upper cover 10, and can generate tension by tightening the nut I15, driving the upper cover 10 to move upward and further compact the sealing ring 11, doubly ensuring sealing reliability and completely eliminating medium leakage.

[0034] In some embodiments, please refer to Figure 1 The sealing packing assembly includes: a guide sleeve 17, a packing pad 18, a packing group 19, and a packing gland 20, which are assembled in the stuffing box of the upper cover 10 in a bottom-to-top order.

[0035] In one example, the packing group 19 is composed of multiple sets of graphite packing rings stacked together. A metal spacer ring is provided between two adjacent sets of graphite packing rings. The metal spacer ring is made of stainless steel and is used to enhance the structural stability of the packing group 19 and prevent the packing rings from deforming or failing under high temperature and high pressure.

[0036] In this embodiment, the guide sleeve 17 guides and limits the valve stem 9, preventing it from shifting during vertical movement. The packing gasket 18 is installed at the bottom, acting as a buffer and pressure reducer, ensuring uniform force on subsequent packing and preventing localized compression deformation that could lead to seal failure. The packing assembly 19 fully fills the gap between the valve stem 9 and the stuffing box of the upper cover 10, adapting to the dynamic movement of the valve stem 9 and achieving efficient sealing. The packing gland 20 applies a continuous and uniform clamping force to the packing assembly 19, ensuring that the packing assembly 19 always fits tightly against the valve stem 9 and the inner wall of the stuffing box, guaranteeing sealing stability and adapting to the dynamic sealing requirements under high temperature and high pressure conditions.

[0037] In some embodiments, please refer to Figure 1 The sealing packing assembly also includes: a packing pressure plate 21, which is stacked on the packing gland 20, with stud II 24 passing through the pre-set bolt hole of the packing pressure plate 21 and the lower end of stud II 24 screwed into the corresponding threaded hole of the upper cover 10; and a disc spring assembly 22, which is fitted on stud II 24 and located between the packing pressure plate 21 and nut II 23, with nut II 23 tightened on the upper end of stud II 24 to press the disc spring assembly 22; wherein, the elastic force of the disc spring assembly 22 is transmitted to the packing gland 20 through the packing pressure plate 21, thereby pressing the packing assembly 19 to ensure the sealing effect.

[0038] In this embodiment, the disc spring assembly 22 utilizes its elastic properties to buffer deformation and pressure fluctuations under operating conditions, preventing excessive clamping force from damaging the packing or insufficient clamping force from causing poor sealing, thus achieving continuous elastic clamping. The packing pressure plate 21 functions to distribute the force, uniformly transmitting the elastic force of the disc spring assembly 22 to the packing gland 20, preventing uneven local force from causing sealing gaps in the packing assembly 19.

[0039] In some embodiments, please refer to Figures 1 to 3 Both the left valve seat 7 and the right valve seat 2 are fixed to the seat cavity of the valve body 1 by welding, forming an integrated structure with the valve body 1, effectively improving the connection strength and sealing stability under high temperature and high pressure conditions. A through hole for a spring 5 is provided on the connecting block 4, and the spring 5 is embedded in the through hole. The left gate plate 6 and the right gate plate 3 are respectively fitted onto the left and right sides of the connecting block 4, and both the left gate plate 6 and the right gate plate 3 abut against the spring 5, so that the elastic force of the spring 5 provides the initial sealing preload for the left gate plate 6 and the right gate plate 3. The bottom of the T-slot of the connecting block 4 has a groove for a pull ring 8, which is embedded in the groove. The pull ring 8 has raised steps on both sides, which respectively engage with the left gate plate 6 and the right gate plate 3 to limit their movement. The lower end of the valve stem 9 is fitted into the top of the T-slot of the connecting block 4 from the side of the T-slot. The lower end of the valve stem 9 is pressed against the pull ring 8 to achieve the limiting and fixing of the pull ring 8 and prevent the pull ring 8 from coming out of the groove of the connecting block 4.

[0040] In this embodiment, the left valve seat 7 and the right valve seat 2 are welded to the valve body 1 to form an integrated structure, which can resist deformation and media impact under extreme working conditions. The spring 5 abuts against the left gate 6 and the right gate 3, which can provide initial sealing pre-tightening force and buffer thermal expansion and contraction to prevent the gates from jamming. The pull ring 8 limits the left gate 6 and the right gate 3 through the raised step to prevent them from displacing and falling off; the valve stem 9 is embedded from the side into the top of the T-slot of the connecting block 4 and abuts against the pull ring 8, which takes into account both limiting fixation and power transmission.

[0041] In some embodiments, please refer to Figures 1 to 3 The left gate 6 and right gate 3 have circular outlines. During the valve opening and closing process, the left gate 6 and right gate 3 can rotate freely relative to the valve seat assembly, resulting in uniform wear of the gate sealing surfaces and effectively extending the overall service life of the valve. The mating sealing surfaces of the left gate 6, right gate 3, left valve seat 7, and right valve seat 2 are all coated with wear-resistant and high-temperature resistant coatings. The coatings are made of nickel-based alloys to improve the wear resistance and high-temperature resistance of the sealing surfaces.

[0042] Next, a method for opening and closing a high-temperature and high-pressure parallel double-gate valve according to an embodiment of the present invention will be described. This method is applied to the above-mentioned high-temperature and high-pressure parallel double-gate valve and includes: When the valve is closed, the left gate 6 and right gate 3 fit together with the left valve seat 7 and right valve seat 2 fixed in the seat cavity of the valve body 1. At this time, the spring 5 in the through hole of the connecting block 4 provides a continuous initial sealing preload to ensure that the gate and the valve seat fit tightly together and prevent medium leakage. At the same time, the circular structure of the left gate 6 and right gate 3 can rotate freely relative to the left valve seat 7 and right valve seat 2 during the fitting process, so that the sealing surfaces of the gate and the valve seat are worn evenly. At this time, the sealing ring 11 between the upper cover 10 and the valve body 1, together with the pressure ring 12 and the four-open ring 13, further blocks the medium leakage channel and achieves double sealing with the sealing packing assembly. When the valve is opened, the valve stem 9 moves the connecting block 4, the left gate 6, and the right gate 3 upward as a whole, separating the gate from the valve seat, allowing the medium to flow smoothly through the internal channel of the valve body 1. During the up-and-down movement of the valve stem 9, the sealing packing assembly in the stuffing box of the upper cover 10 plays its role, and the elastic force of the disc spring assembly 22 is transmitted to the packing gland 20 through the packing pressure plate 21, pressing the packing assembly 19 to achieve dynamic sealing between the valve stem 9 and the upper cover 10, preventing the medium from leaking along the valve stem 9.

[0043] In summary, this technical solution adopts a baffle-less design, using raised steps on both sides of the pull ring to hold the left and right gate plates in place, effectively preventing the gate plates from detaching. It also eliminates the traditional welded baffle structure, removing the welding process and reducing production costs. The pull ring is installed in the groove at the bottom of the T-slot of the connecting block, and the lower end of the valve stem presses against the pull ring to achieve limiting and fixing, eliminating the need for fastening screws and preventing the safety risk of fastening screws falling into the valve cavity during valve use. The connecting block adopts an open installation structure, with the valve stem inserted from the side of the T-slot, eliminating time-consuming processes such as valve stem assembly and threaded connections. It significantly improves assembly efficiency and makes internal parts replacement convenient and quick. The left and right gates are respectively installed on the left and right sides of the connecting block and pressed onto the spring, placed between the left and right valve seats. The spring provides initial sealing force, which can effectively prevent valve movement from getting stuck or jammed under high temperature conditions, ensuring smooth valve operation. At the same time, the left and right gates are designed with a circular outline, which can rotate freely during valve operation, so that the sealing surface wears evenly and effectively extends the service life of the valve. Overall, it realizes safe, stable and efficient valve operation, which has significant practical and economic advantages compared with existing technologies.

[0044] In the embodiments disclosed in this invention, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments disclosed in this invention according to the specific circumstances.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A high-temperature and high-pressure parallel double-gate valve, comprising a valve body (1), characterized in that, The high-temperature and high-pressure parallel double-gate valve also includes: The valve seat assembly includes a left valve seat (7) and a right valve seat (2), which are respectively installed in the preset seat cavity of the valve body (1); A gate assembly, comprising a left gate (6) and a right gate (3), is symmetrically arranged between the left valve seat (7) and the right valve seat (2) for fitting with the valve seat assembly to achieve sealing; The connecting transmission assembly includes a connecting block (4), a spring (5), a pull ring (8), and a valve stem (9). The connecting block (4) is embedded between the left gate plate (6) and the right gate plate (3). The spring (5) is mounted on the connecting block (4). The pull ring (8) is connected to the connecting block (4), the left gate plate (6), and the right gate plate (3) respectively. The valve stem (9) is correspondingly engaged with the pull ring (8) and passes through the upper cover assembly to transmit opening and closing power. The upper cover assembly includes an upper cover (10), a cover plate (14), a stud I (16), and a nut I (15). The upper cover (10) is installed at the head of the valve body (1). The cover plate (14) covers the upper end of the middle cavity of the valve body (1). The stud I (16) and the nut I (15) are threaded together to connect the cover plate (14) and the upper cover (10). The sealing packing assembly is installed in the pre-set stuffing box of the upper cover (10) to achieve dynamic sealing between the valve stem (9) and the upper cover (10) to prevent media leakage.

2. The high-temperature and high-pressure parallel double-gate valve according to claim 1, characterized in that, The upper cover assembly also includes: A sealing ring (11) is fitted between the mating surfaces of the upper cover (10) and the valve body (1); A pressure ring (12), which is stacked on top of the sealing ring (11); and The four-ring (13) is assembled above the pressure ring (12) and inserted into the pre-set central cavity ring groove of the valve body (1) to press the sealing ring (11) to improve the sealing performance between the upper cover (10) and the valve body (1) and prevent media leakage.

3. The high-temperature and high-pressure parallel double-gate valve according to claim 2, characterized in that, The stud I (16) passes through the pre-set mounting hole of the cover plate (14), the lower end of the stud I (16) is screwed into the corresponding threaded hole of the upper cover (10), and the nut I (15) is tightened on the upper end of the stud I (16) and fits against the upper surface of the cover plate (14). The upper cover (10) is moved upward by the pulling force generated by tightening the nut I (15) to press the sealing ring (11) and enhance the sealing reliability.

4. The high-temperature and high-pressure parallel double-gate valve according to claim 1, characterized in that, The sealing packing assembly includes: The guide sleeve (17), packing gasket (18), packing assembly (19), and packing gland (20) are assembled in the stuffing box of the upper cover (10) in the order from bottom to top.

5. The high-temperature and high-pressure parallel double-gate valve according to claim 4, characterized in that, The sealing packing assembly further includes: A packing pressure plate (21) is stacked on the packing gland (20), and a stud II (24) passes through a pre-set bolt hole in the packing pressure plate (21). The lower end of the stud II (24) is screwed into a corresponding threaded hole in the upper cover (10); and Disc spring assembly (22), which is fitted on stud II (24) and located between the packing pressure plate (21) and nut II (23), the nut II (23) is tightened on the upper end of stud II (24) to press the disc spring assembly (22). The elastic force of the disc spring assembly (22) is transmitted to the packing gland (20) through the packing pressure plate (21), thereby pressing the packing assembly (19) to ensure a sealing effect.

6. The high-temperature and high-pressure parallel double-gate valve according to claim 1, characterized in that, The left valve seat (7) and the right valve seat (2) are both fixed to the seat cavity of the valve body (1) by welding. The left valve seat (7) and the right valve seat (2) form an integrated structure with the valve body (1), which effectively improves the connection strength and sealing stability under high temperature and high pressure conditions. The left gate (6) and the right gate (3) are respectively fitted and assembled on the left and right sides of the connecting block (4), and the left gate (6) and the right gate (3) are respectively abutted against the spring (5) so as to provide the initial sealing pre-tightening force of the left gate (6) and the right gate (3) through the elastic force of the spring (5); The connecting block (4) has a through hole adapted to the spring (5), and the spring (5) is fitted into the through hole.

7. The high-temperature and high-pressure parallel double-gate valve according to claim 1, characterized in that, The bottom of the T-shaped groove of the connecting block (4) is provided with a groove for adapting to the pull ring (8). The pull ring (8) is embedded in the groove, and the two sides of the pull ring (8) are provided with raised steps. The raised steps are respectively engaged and adapted to the left gate (6) and the right gate (3) for limiting the left gate (6) and the right gate (3).

8. The high-temperature and high-pressure parallel double-gate valve according to claim 7, characterized in that, The lower end of the valve stem (9) is fitted into the top of the T-slot of the connecting block (4) from the side of the T-slot. The lower end of the valve stem (9) is pressed against the pull ring (8) to achieve the limiting and fixing of the pull ring (8) and prevent the pull ring (8) from coming out of the groove of the connecting block (4).

9. The high-temperature and high-pressure parallel double-gate valve according to claim 1, characterized in that, The outlines of the left gate (6) and the right gate (3) are circular. During the valve opening and closing process, the left gate (6) and the right gate (3) can rotate freely relative to the valve seat assembly, so that the gate sealing surface wears evenly and effectively extends the overall service life of the valve. The mating sealing surfaces of the left gate (6), the right gate (3), the left valve seat (7), and the right valve seat (2) are all provided with wear-resistant and high-temperature resistant coatings. The coatings are made of nickel-based alloy material and are used to improve the wear resistance and high-temperature resistance of the sealing surfaces.

10. The high-temperature and high-pressure parallel double-gate valve according to claim 4, characterized in that, The packing group (19) is composed of multiple sets of graphite packing rings stacked together. A metal spacer is provided between two adjacent sets of graphite packing rings. The metal spacer is made of stainless steel and is used to enhance the structural stability of the packing group (19) and prevent the packing rings from deforming or failing under high temperature and high pressure.

11. The high-temperature and high-pressure parallel double-gate valve according to claim 2, characterized in that, The sealing ring (11) is made of flexible graphite and metal winding, and its cross-section is trapezoidal. It is used to improve the fit between the sealing ring (11) and the mating surfaces of the upper cover (10) and the valve body (1) and enhance the sealing performance.

12. A method for opening and closing a high-temperature and high-pressure parallel double-gate valve, the method being applied to the high-temperature and high-pressure parallel double-gate valve as described in any one of claims 1 to 11, characterized in that, The method includes: When the valve is closed, the left gate (6) and right gate (3) fit together with the left valve seat (7) and right valve seat (2) fixed in the seat cavity of the valve body (1). At this time, the spring (5) in the through hole of the connecting block (4) provides a continuous initial sealing pre-tightening force to ensure that the gate and the valve seat fit tightly together and prevent medium leakage. At the same time, the circular structure of the left gate (6) and the right gate (3) can rotate freely relative to the left valve seat (7) and the right valve seat (2) during the fitting process, so that the sealing surface of the gate and the valve seat is worn evenly. At this time, the sealing ring (11) between the upper cover (10) and the valve body (1) cooperates with the pressure ring (12) and the four-open ring (13) to further block the medium leakage channel and achieve double sealing with the sealing packing assembly. When the valve is opened, the valve stem (9) drives the connecting block (4), the left gate (6), and the right gate (3) to move upward as a whole, so that the gate is separated from the valve seat and the medium flows smoothly through the internal channel of the valve body (1). During the up and down movement of the valve stem (9), the sealing packing assembly in the stuffing box of the upper cover (10) plays a role, and the elastic force of the disc spring assembly (22) is transmitted to the packing gland (20) through the packing pressure plate (21), which presses the packing assembly (19) to achieve dynamic sealing between the valve stem (9) and the upper cover (10) and prevent the medium from leaking along the valve stem (9).

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