Medium self-pressurizing seal adjusting valve structure and self-adapting seal method

Abstract

The application discloses a medium self-pressurizing sealing adjusting valve structure and a self-adapting sealing method, and belongs to the technical field of fluid valve sealing. The adjusting valve of the application adopts a three-section split valve body, is divided into two independent sealing valve cavities, and is internally arranged with a multistage valve core valve seat sealing assembly. In a normal state, three layers of sealing are formed by end face sealing, radial plugging and elastic compression. Medium flow regulation is completed by driving the valve core through the valve rod. A self-adapting sealing mechanism adapted to high and low pressures is arranged. Through a high-temperature tripping type mechanical connection structure, after mechanical limiting failure occurs in a high-temperature dangerous situation, the low-pressure state is closed and locked by the valve core pushed by a top spring piece, and the high-pressure state is self-pressurized and plugged by the channel with the help of the self-pressure of the medium, so that double emergency sealing protection is formed. The application solves the problems of poor sealing, high-temperature failure and weak working condition adaptation of traditional valves. The pure mechanical structure does not need external energy, multistage sealing guarantees whole-process protection, and can be widely applied to various high-temperature high-pressure flammable and explosive fluid conveying pipelines.

Description

Technical Field

[0001] This invention relates to the field of fluid valve sealing control technology, specifically to a medium self-pressurization sealing regulating valve structure and an adaptive sealing method. Background Technology

[0002] Control valves, as core control components of industrial fluid transport systems, are widely used in critical fields such as petroleum refining, coal chemical industry, natural gas gathering and transportation, fine chemicals, hydrogen energy storage and transportation, nuclear power, and long-distance oil and gas pipelines. They are primarily used to achieve flow regulation, pressure control, and on / off interlocking of media. Applicable media include flammable and explosive fluids such as hydrogen, methane, ethylene, liquefied petroleum gas, gasoline, diesel, and aviation kerosene; high-temperature and high-pressure fluids such as high-temperature hot oil, high-pressure superheated steam, molten salt, and high-temperature syngas; and highly corrosive, toxic, and harmful fluids such as liquid chlorine, liquid ammonia, hydrogen sulfide, acidic natural gas, and highly toxic chemical intermediates. Leakage of any of these media during regulation can easily lead to major safety accidents such as fires, explosions, poisoning, and environmental pollution. Therefore, extremely high requirements are placed on the sealing reliability, high-temperature stability, and emergency interlocking capabilities of control valves.

[0003] Currently, traditional control valves have the following systemic technical defects when used in the aforementioned high-risk operating conditions:

[0004] 1. The sealing structure is simple. Conventional control valves generally use a single-stage valve core-seat seal. The sealing pair relies on a single contact sealing with only line seal or surface seal. The sealing path is short and the redundancy is low. Under the long-term impact of high pressure differential media, temperature cycle, and wear from particulate impurities, the sealing surface quickly develops scratches, deformation, and erosion, leading to micro-leakage, continuous dripping, and jetting leakage. This cannot meet the low leakage and zero leakage level requirements of API 6D and ISO 15848-1. In pipelines carrying flammable and explosive media such as hydrogen, methane, and liquefied gas, even a small leak can trigger a safety accident.

[0005] 2. Rapid Failure of Mechanical Transmission Structures under High-Temperature Fire Conditions: In extreme scenarios such as fires, high furnace temperatures, and pipeline overheating, the ambient temperature can rise to 400℃~800℃ in a short time. Traditional control valves often use rigid pin connections, threaded connections, key connections, and other fixed structures between the valve stem and valve core, and between the valve core and transmission components. The structural components used will experience a sharp drop in strength, thermal softening, and yielding deformation above 350℃. When the connecting pin, connecting rod, or thread fails, the valve core loses its axial restraint, causing it to move, disengage, or jam. The main sealing pair separates instantly, the flow channel is completely open, and a large amount of medium leaks out, leading to a rapid expansion of the accident.

[0006] 3. Emergency sealing is highly dependent on external energy and completely fails under extreme conditions. Existing emergency shut-off valves and emergency locking valves generally use pneumatic, electric, or hydraulic actuators, which rely on external air sources, power sources, and hydraulic stations to provide locking power. However, in real emergencies such as fires, explosions, and pipeline damage, the external energy system is often the first to be damaged, interrupted, or lose pressure. The actuator cannot operate, and the valve cannot be closed or locked, forming an "uncontrolled open flow channel" and losing its last line of safety protection.

[0007] 4. Poor adaptability to high and low pressure conditions, with obvious sealing blind spots. Traditional control valves rely on fixed springs or actuators for sealing force, which cannot adaptively adjust with media pressure. Under low pressure conditions, insufficient spring preload leads to insufficient sealing specific pressure and sealing failure; under high pressure conditions, uneven stress on the sealing surface and excessive specific pressure result in plastic deformation or intensified erosion. Furthermore, the valve cannot automatically switch sealing strategies based on pipeline pressure, resulting in obvious pressure blind spots between areas where low pressure and high pressure sealing are inadequate, failing to provide reliable sealing across the entire pressure range.

[0008] 5. The opening pressure and flow coefficient are contradictory, limiting the regulation performance. When the traditional valve core structure reduces the sealing diameter to reduce the opening force, the flow area shrinks sharply, and the flow coefficient drops significantly, which cannot meet the needs of large flow regulation. On the other hand, when the sealing diameter is increased to increase the flow, the sealing contact area increases, the opening pressure rises significantly, the spring adjustment range narrows, and the regulation accuracy deteriorates under high pressure differential. At the same time, the medium directly erodes the sealing surface, further reducing the valve's service life and regulation stability.

[0009] 6. Lack of redundant emergency sealing mechanism; single-point failure leads to complete loss of control. Traditional control valves only have one main sealing structure, with no backup seal, no secondary interlock, and no redundant protection. When the main seal fails due to erosion, high temperature, or mechanical damage, there is no secondary sealing structure to connect it, the flow channel is directly connected, the medium is completely out of control, and it cannot meet the inherent safety requirements of high-risk fluids.

[0010] In summary, existing control valves cannot simultaneously meet the five core requirements of high-temperature reliability, passive self-adaptation, all-condition protection, high and low pressure self-adaptation, and redundant emergency sealing, making it difficult to provide full life-cycle safety assurance for flammable, explosive, high-temperature, high-pressure, and toxic and harmful fluids. Summary of the Invention

[0011] To address the shortcomings of existing technologies, such as low sealing reliability, easy failure under high-temperature conditions, poor pressure adaptability, and reliance on external drives, this invention provides a medium self-pressurization sealing regulating valve structure and an adaptive sealing method, which enables adjustable flow rate under normal conditions and automatic switching of sealing mode in high-temperature and high-risk scenarios, achieving sealing protection under all operating conditions.

[0012] To achieve the above objectives, the technical solution adopted by this invention is as follows: a medium self-pressurizing sealing regulating valve structure, comprising a valve body divided into three sections: an inlet valve section, a middle valve section, and a valve cover section; the valve cover section and the middle valve section enclose a first sealing valve cavity, and the middle valve section and the inlet valve section enclose a second sealing valve cavity; a throttling cylinder valve seat and a sealing valve core are disposed within the first sealing valve cavity; a radial hole is opened on the side wall of the throttling cylinder valve seat, and an axial flow opening is provided axially; the outer side of the throttling cylinder valve seat has an end face abutting a sealing surface; the sealing valve core is provided with a double sealing cylinder, which is engaged with the inner and outer sides of the throttling cylinder valve seat to block the radial hole, forming a second sealing structure; the outer cylinder of the double sealing cylinder is attached to the end face of the throttling cylinder valve seat to abut the sealing surface, forming a first sealing structure; a valve stem is connected to the upper end of the sealing valve core; under low flow conditions, the valve stem drives the sealing valve core to move and open the radial hole, allowing the medium to pass through the radial hole; under extreme conditions, the valve stem drives the sealing valve core to move and disengage from the throttling cylinder valve seat, allowing the medium to still pass through axially. The axial flow opening is used for outflow; the second sealing valve cavity is provided with a flow orifice valve seat and a dynamic valve core; an abutment rod with an externally sleeved spring is provided at the lower end of the sealing valve core, and the bottom end of the abutment rod abuts against the back of the dynamic valve core to form a limit on its movement; in the closed state, the end of the abutment rod abuts against the back of the dynamic valve core, pressing the dynamic valve core against the flow orifice valve seat to form a third sealing structure; in the self-pressure opening state, the valve stem drives the sealing valve core to move, the abutment rod no longer abuts, and the spring force presses the dynamic valve core, providing a dynamic sealing flow channel that adapts to changes in medium pressure; the bottom of the sealing valve core is also equipped with a top spring that pushes the sealing valve core to move towards the throttle valve seat; under high temperature and open flame conditions, the limiting connection structure of the valve stem and the abutment rod fails; when the medium pressure is lower than the critical point A, the top spring pushes the sealing valve core to lock against the throttle valve seat to form a fourth sealing structure; when the medium pressure is higher than the critical point A, the medium self-pressurizes and pushes the dynamic valve core upward to block the lower port of the throttle valve seat to form a fifth sealing structure.

[0013] As a further feature of the above scheme, the double sealing cylinder is a double-layer integrated sleeve, wherein the outer wall of the inner cylinder is fitted to the inner wall of the throttle valve seat, and the inner wall of the outer cylinder is fitted to the outer wall of the throttle valve seat, fully covering the radial hole, and the axial difference between the end faces of the outer cylinder and the inner cylinder is greater than the diameter of the radial hole.

[0014] As a further feature of the above solution, the spring and the top spring are made of high-temperature resistant alloy material, which can withstand high-temperature environment and maintain the elastic performance unchanged. The spring is pre-compressed and assembled between the abutment rod and the dynamic valve core, and the top spring is pre-compressed and assembled between the sealing valve core and the end face of the valve cover.

[0015] As a further feature of the above scheme, the upper end of the dynamic valve core is a spherical sealing end, and the lower port of the throttle valve seat is provided with a conical sealing surface, which can fit with the upper end of the dynamic valve core to achieve sealing and plugging. Both the dynamic valve core and the sealing valve core have concave spherical arc surfaces on their downward-facing main body ends.

[0016] As a further feature of the above solution, a high-temperature release connection is provided between the valve stem and the sealing valve core, and between the sealing valve core and the abutment rod. Under high-temperature conditions, the rigid limit constraint is automatically released, and the spring component and the top spring component provide elastic pressure constraint.

[0017] The high-temperature tripping connection includes an inner central hole sleeve structure on the valve stem and the abutment rod, including an outer sleeve rod, an inner sleeve rod, and a radial pin. The radial pin is radially inserted to provide axial limiting constraint for both the outer sleeve rod and the inner sleeve rod. The radial pin is also used to overcome the axial shear force load of the sealing valve core driven by the medium and the dynamic valve core transmitted when the valve stem rises and falls to seal the valve core.

[0018] As a further setting of the above scheme, the critical point A is set to a value that matches the elasticity parameter of the top spring, and is specifically designed to overcome the reaction force that pushes the dynamic valve core against the lower end of the throttle valve seat. The critical point A is used for adaptive double locking seal under working conditions.

[0019] The technical solution of the present invention also includes a medium self-pressurization adaptive sealing method, comprising a conventional sealing adjustment mode and an extreme working condition adaptive sealing mode:

[0020] Conventional sealing adjustment: The valve stem drives the sealing valve core to rise and fall. The double sealing cylinder forms the first sealing structure and the second sealing structure to block the medium passage. The spring element presses against the dynamic valve core to form the third sealing structure. The flow rate of the medium is adjusted by the change of the valve core stroke.

[0021] Extreme low-pressure sealing: High temperature causes the mechanical limiting of the sealing valve core and the dynamic valve core to fail. The medium pressure is lower than the critical point A. The medium pressure is greater than the weight sealing force of the dynamic valve core, but less than the pressure that pushes the dynamic valve core to move upward and block the lower port of the throttle valve seat. At this time, the dynamic valve core fails and the second sealing valve cavity does not have a seal. At the same time, based on the valve stem losing the mechanical limiting constraint on the sealing valve core, the sealing valve core moves towards the direction of fitting the throttle valve seat with the weight and the pushing force of the top spring. After overcoming the medium pressure, it completes the passive sealing and locking by relying on the weight and the elastic force of the top spring.

[0022] Extreme high-pressure sealing: High temperature causes the mechanical limiting of the sealing valve core and the dynamic valve core to fail, and the medium pressure is higher than the critical point A. This medium pressure is greater than the sealing valve core due to its weight and the pushing force of the top spring. At this time, the first sealing valve cavity no longer has a seal. However, the high medium pressure also makes the medium pressure itself complete the process of pushing the dynamic valve core to move upward and block the lower port of the throttle valve seat. Based on the fact that the higher the medium pressure, the stronger the sealing clamping force, the passive sealing lock is completed by means of the medium self-pressurization.

[0023] As a further provision of the above scheme, a high-temperature tripping connection structure is provided between the valve stem and the sealing valve core, and between the sealing valve core and the abutment rod. The high-temperature tripping connection structure includes an inner central hole sleeve structure opened on the connecting component, an outer sleeve rod and an inner sleeve rod inserted into it, and a radial pin inserted between the two. The radial pin is made of high-strength alloy steel (such as 40CrNiMo4 or 17-4PH), whose yield strength and shear strength are sufficient to withstand the axial shear force generated by the medium pressure in the range of room temperature to 300℃. When the ambient temperature rises to above 400℃ due to a fire, the radial pin material undergoes significant thermal softening, and its strength drops sharply. Under the self-weight of the valve core or the action of a small external force, it will undergo shear fracture or plastic failure, thereby releasing the rigid limiting constraint of the valve stem on the valve core.

[0024] Beneficial effects: The medium self-pressurization sealing regulating valve structure of the present invention has a three-section split structure, which is spliced ​​in pairs to form an independent first sealing valve cavity and a second sealing valve cavity. The sealing valve core assembly and the dynamic valve core assembly are respectively assembled in the two valve cavities.

[0025] The throttle valve seat integrates flow and sealing structures, and the sealing valve core is equipped with double sealing cylinders, forming both end face sealing and radial plugging sealing; the valve core is driven to move by the valve stem to realize pipeline opening and closing and flow regulation;

[0026] The lower end of the sealing valve core has a rigid and elastic abutment structure, which includes rigid compression constraint when the valve is closed and dynamic sealing when the valve is opened under normal conditions.

[0027] A spring is installed at the bottom of the sealing valve core as an emergency sealing power component.

[0028] In extreme environments such as high temperatures, if the mechanical limit structure fails to trip, the valve enters an adaptive sealing state.

[0029] When the medium is in the low-pressure range, the sealing valve core is pushed by the top spring to fit the valve seat into the first sealing valve cavity to complete the seal.

[0030] When the medium is in the high-pressure range, the medium's own pressure drives the dynamic valve core to block the channel. The medium pressure increases itself to enhance the sealing effect. High and low pressures correspond to different sealing structures, providing double protection to prevent medium leakage.

[0031] This invention also proposes an adaptive sealing method adapted to this structure, which divides the working mode into three modes: normal adjustment, low-pressure emergency sealing, and high-pressure emergency sealing. The sealing mode is automatically switched according to the working environment and medium pressure, without the need for external energy intervention throughout the process.

[0032] The sealing regulating valve of this invention features a five-stage sealing structure, providing protection under both conventional and extreme conditions. Its comprehensive sealing protection effectively reduces the risk of leakage. Furthermore, the sealing mode adaptively switches between high and low pressure media, corresponding to appropriate interlocking methods, resulting in a wide range of operating conditions. This sealing structure employs a purely mechanical, self-locking mechanism, independent of electrical and pneumatic components. In high-temperature fire environments, it automatically triggers stable operation based on the temperature's effect on specific materials. With high structural integration, it combines flow regulation and safety interlocking functions, offering convenient installation and use, a long service life, and wide applicability to various high-temperature, high-pressure, flammable, and explosive fluid transport pipelines. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the internal cross-sectional structure of the regulating valve in the open state of the present invention.

[0034] Figure 2 This is a schematic diagram of the internal cross-sectional structure of the regulating valve in the closed state of the present invention.

[0035] Figure 3 This is a schematic diagram of the dynamic overcurrent structure of the present invention.

[0036] Figure 4 This is a schematic diagram of the internal sealing structure of the low-pressure medium valve under extreme conditions according to the present invention.

[0037] Figure 5 This is a schematic diagram of the internal sealing structure of the high-pressure valve for extreme conditions of the present invention.

[0038] Reference numerals: 1. Valve body; 11. Inlet valve section; 12. Middle valve section; 13. Valve cover section; 2. Sealing valve core; 21. Double sealing cylinder; 211. Outer cylinder; 212. Inner cylinder; 26. Abutment rod; 27. Spring element; 28. Top spring element; 3. Throttling cylinder valve seat; 31. Radial hole; 32. Axial flow opening; 33. End face abutment sealing surface; 4. First sealing valve cavity; 5. Second sealing valve cavity; 6. Dynamic valve core; 65. Conical sealing surface; 66. Spherical sealing end; 67. Concave spherical arc surface; 7. Flow hole valve seat; 9. Valve stem; 91. Outer sleeve rod; 92. Inner sleeve rod; 93. Radial pin. Detailed Implementation

[0039] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments and features described in these embodiments can be combined with each other.

[0040] refer to Figures 1 to 5 As shown, the present invention provides a medium self-pressurization sealing regulating valve structure, which mainly includes a valve body 1, a sealing valve core 2, a throttling cylinder valve seat 3, a dynamic valve core 6, a flow orifice valve seat 7, and a valve stem 9.

[0041] The valve body 1 adopts a three-section split structure, consisting of an inlet valve section 11, a middle valve section 12, and a valve cover section 13 connected sequentially through a sealing fit. The valve cover section 13 and the middle valve section 12 enclose a first sealed valve cavity 4, and the middle valve section 12 and the inlet valve section 11 enclose a second sealed valve cavity 5. The first sealed valve cavity 4 and the second sealed valve cavity 5 are independent of each other, forming a double-isolated sealed cavity structure, which can effectively prevent media cross-cavity leakage and improve sealing reliability.

[0042] A throttle valve seat 3 is fixedly installed inside the first sealing valve cavity 4. The sidewall of the throttle valve seat 3 has several radial holes 31 evenly distributed circumferentially, an axial flow opening 32, and an end face abutting a sealing surface 33 on its upper outer side. A sealing valve core 2 is also installed inside the first sealing valve cavity 4, and the sealing valve core 2 is integrally formed with a double sealing cylinder 21. The double sealing cylinder 21 includes an outer cylinder 211 and an inner cylinder 212. The outer wall of the inner cylinder 212 fits against the inner wall of the throttle valve seat 3, and the inner wall of the outer cylinder 211 fits against the outer wall of the throttle valve seat 3, completely covering the radial holes 31. The end face of the outer cylinder 211 facing the throttle valve seat 3 abuts against the end face sealing surface 33, forming a first sealing structure; the inner cylinder 212 and the outer cylinder 211 together seal the radial holes 31, forming a second sealing structure. The axial difference between the end faces of the outer cylinder 211 and the inner cylinder 212 is greater than the diameter of the radial hole 31, so that the sealing action is achieved in the order of sealing the end face first and then sealing the radial hole, thus eliminating the risk of gap leakage.

[0043] The upper end of the sealing valve core 2 is connected to the valve stem 9, and is driven by the valve stem 9 to move up and down axially to change the medium flow area and achieve flow regulation. Under low flow conditions, the movement of the sealing valve core 2 causes the radial holes 31 to open gradually, and the medium flows through the radial holes 31 (the limit is that all radial holes 31 are fully open); under high flow or fully open conditions, the sealing valve core 2 disengages from the throttle valve seat 3, and the medium flows through the axial flow opening 32.

[0044] A contact rod 26 extends from the lower end of the sealing valve core 2, and a spring element 27 is sleeved on the outside of the contact rod 26. The second sealing valve chamber 5 contains a flow orifice valve seat 7 and a dynamic valve core 6, with the bottom end of the contact rod 26 abutting against the back of the dynamic valve core 6. In the closed state, the contact rod 26 presses the dynamic valve core 6 against the flow orifice valve seat 7, forming a third sealing structure. In the self-pressure open state, the valve stem 9 moves the sealing valve core 2 upward, the contact rod 26 releases its rigid contact with the dynamic valve core 6, and the spring element 27 provides elastic preload, enabling the dynamic valve core 6 to achieve adaptive dynamic sealing as the medium pressure changes.

[0045] A top spring 28 is provided between the sealing valve core 2 and the valve cover 13. The top spring 28 is assembled in a pre-compressed state and can push the sealing valve core 2 toward the throttle valve seat 3. Both the spring 27 and the top spring 28 are made of high-temperature resistant alloy material, which can maintain stable elastic performance in the temperature range of -29℃ to 650℃. The elasticity retention rate at high temperature is not less than %, ensuring that reliable sealing force can still be provided under extreme working conditions.

[0046] The upper end of the dynamic valve core 6 is configured as a spherical sealing end 66, and the lower end of the throttling cylinder valve seat 3 is provided with a conical sealing surface 65 that matches the spherical sealing end 66. The two fit together to form a stable and reliable seal. The lower end faces of both the dynamic valve core 6 and the sealing valve core 2 are provided with concave spherical arc surfaces 67, which are used to optimize the medium flow field, reduce scouring, reduce flow resistance, and extend the service life of the sealing surface.

[0047] The valve stem 9 and the sealing valve core 2, as well as the sealing valve core 2 and the abutment rod 26, are all connected by a high-temperature release mechanical connection. This connection structure includes an outer sleeve rod 91, an inner sleeve rod 92, and a radial pin 93. The outer sleeve rod 91 and the inner sleeve rod 92 are sleeved together, and the radial pin 93 is inserted radially to achieve axial limiting. The radial pin 93 is made of 40CrNiMo4 high-strength alloy steel, and its shear strength is not less than 500MPa in the range of room temperature to 350℃, which can reliably withstand the axial shear load under normal working conditions. When the ambient temperature reaches above 400℃, the radial pin 93 undergoes thermal softening failure, and the shear strength drops to below 150MPa, automatically releasing the rigid limiting constraint and causing the valve core assembly to switch to an elastic constraint state.

[0048] In this embodiment, a critical pressure point A is set. The critical point A is determined by matching the elastic force parameter of the top spring 28 with the effective pressure-bearing area of ​​the dynamic valve core 6, which is used to achieve adaptive switching between low-pressure emergency sealing and high-pressure self-pressurizing sealing. When the medium pressure is lower than the critical point A, the top spring 28 provides the sealing locking force; when the medium pressure is higher than the critical point A, the medium's own pressure achieves self-pressurizing sealing locking, with no sealing blind spots throughout the process.

[0049] This embodiment also provides a medium self-pressurization adaptive sealing method, including a conventional sealing adjustment mode, an extreme low-pressure sealing mode, and an extreme high-pressure sealing mode:

[0050] Conventional sealing adjustment mode: Valve stem 9 drives the sealing valve core 2 to rise and fall axially. The double sealing cylinder 21 cooperates with the throttle valve seat 3 to form the first sealing structure and the second sealing structure. The spring element 27 presses the dynamic valve core 6 against the flow hole valve seat 7 to form the third sealing structure. The precise adjustment of the medium flow rate is achieved by the change of the stroke of the sealing valve core 2.

[0051] Extreme low-pressure sealing mode: High-temperature operating conditions cause the high-temperature trip connection to fail, and the valve stem 9 and the sealing valve core 2 are released from rigid restraint. When the medium pressure is lower than the critical point A, the top spring 28 pushes the sealing valve core 2 to move towards the throttle valve seat 3 and fit tightly, forming a fourth sealing structure, realizing passive sealing and locking under low-pressure conditions.

[0052] Extreme high-pressure sealing mode: After the high-temperature trip connection fails, when the medium pressure is higher than the critical point A, the medium pressure pushes the dynamic valve core 6 upward, causing the spherical sealing end 66 to fit tightly against the conical sealing surface 65, forming the fifth sealing structure. The higher the medium pressure, the greater the sealing clamping force, achieving self-pressurized enhanced sealing lock.

[0053] In this embodiment, a critical point A is set as the unique, clear, and blind-zone-free switching boundary between the sealing valve core 2 and the dynamic valve core 6 after high-temperature tripping failure.

[0054] It is worth noting the physical significance of the critical point A mentioned in this invention:

[0055] The critical point A is determined by the preload of the top spring 28 and the effective pressure-bearing area of ​​the dynamic valve core 6. Its value is equal to the minimum medium pressure that enables the dynamic valve core 6 to just overcome the force of the spring 27 and seal upward.

[0056] When the medium pressure is below the critical point A: the downward thrust of the spring element 27 and the downward force of the dynamic valve core 6 are greater than the lifting force of the medium on the dynamic valve core 6. At the same time, the pressure of the medium is not enough to push the dynamic valve core 6 to the lower port of the throttle valve seat 3 to block the valve. At this time, the dynamic valve core 6 is suspended in the middle of the second sealing cavity 5, and the medium can pass through the second sealing cavity 5.

[0057] When the medium pressure is higher than the critical point A: specifically, when the medium thrust is greater than the thrust of the spring element 27, the dynamic valve core 6 is automatically lifted and sealed by the medium pressure. Before the medium pressure drops, under normal circumstances, within a certain range, the greater the inlet side pressure, the stronger the pushing force on the dynamic valve core 6, thereby achieving self-pressurization and sealing of the medium.

[0058] This achieves full-range adaptive sealing, relying on springs for low pressure and the medium for high pressure, with no pressure blind spots and no failure gaps.

[0059] The specific design is as follows:

[0060] ① When does the sealing valve core 2 work after high-temperature tripping (low-pressure condition)?

[0061] When a fire or high temperature causes radial pin 93 to break and the mechanical rigid lock is completely released:

[0062] Valve stem 9 no longer controls sealing valve core 2;

[0063] The abutment rod 26 no longer provides rigid restraint to the dynamic valve core 6.

[0064] If the pressure of the medium in the pipeline is less than the critical point A, the upward force of the medium pushing the dynamic valve core 6 is insufficient to overcome the downward preload of the top spring 28, and the dynamic valve core 6 cannot be brought into contact with the lower port of the throttle valve seat 3 to achieve a seal.

[0065] Under this medium pressure condition: the sealing valve core 2 moves downward under the push of the top spring 28 and re-fits tightly with the throttle valve seat 3. The double sealing cylinder 21 forms an end face seal and radial blockage, constituting a fourth sealing structure, and realizing reliable locking under low pressure.

[0066] That is: low pressure → sealing valve core 2 works, dynamic valve core 6 does not work (it may also be that the pressure is too low, and dynamic valve core 6 moves directly to the bottom, sealing the opening into the second sealing chamber 5).

[0067] ② When does the dynamic valve core 6 operate after high-temperature tripping (high-pressure condition)?

[0068] Similarly, after high-temperature tripping and mechanical limit failure: if the medium pressure in the pipeline is greater than the critical point A: the axial thrust (lifting force) of the medium on the dynamic valve core 6 is greater than the downward force of the spring 27 on the dynamic valve core 6. At this time, the medium pressure is sufficient to lift the dynamic valve core 6 upward.

[0069] In this state: the spherical sealing end 66 at the upper end of the dynamic valve core 6 is forcibly fitted and locked with the conical sealing surface 65 at the lower port of the throttle valve seat 3, forming the fifth sealing structure.

[0070] The higher the medium pressure, the greater the sealing specific pressure, thus achieving a self-pressurizing enhanced seal.

[0071] At this time, although the sealing valve core 2 loses mechanical control, the first sealing valve chamber 4 no longer undertakes the main sealing function because the dynamic valve core 6 has completely blocked the main channel. The dynamic valve core 6 completes the full channel locking.

[0072] That is: high pressure → dynamic valve core 6 works, sealing valve core 2 does not work.

[0073] The sealing structure of the regulating valve of this invention is designed to automatically switch the sealing mode according to the medium pressure under extreme conditions such as fire, overheating, and external power interruption, without the need for power, gas or hydraulic power. It achieves full-process sealing protection and is especially suitable for the transportation and control of high-risk media such as hydrogen, methane, liquefied petroleum gas, high-temperature hot oil, high-pressure steam and toxic and harmful fluids.

[0074] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A medium self-pressurization sealing regulating valve structure, characterized in that: The valve body (1) comprises a three-section structure consisting of an inlet valve section (11), a middle valve section (12), and a valve cover section (13). The valve cover section (13) and the middle valve section (12) together form a first sealed valve cavity (4), and the middle valve section (12) and the inlet valve section (11) together form a second sealed valve cavity (5). A throttle valve seat (3) and a sealing valve core (2) are provided in the first sealed valve cavity (4). The throttle valve seat (3) has a radial hole (31) on its side wall and an axial flow opening (32) on its axial direction. The outer side of the throttle valve seat (3) has an end face abutting a sealing surface (33). The sealing valve core (2) has a double sealing surface. The sealing cylinder (21) is fitted inside and outside the throttle valve seat (3) to block the radial hole (31) and form a second sealing structure. The outer cylinder (211) of the double sealing cylinder (21) is attached to the end face of the throttle valve seat (3) and abuts against the sealing surface (33) to form a first sealing structure. The upper end of the sealing valve core (2) is connected to the valve stem (9). Under low flow conditions, the valve stem (9) drives the sealing valve core (2) to move and open the radial hole (31). The medium passes through the radial hole (31). Under extreme conditions, the valve stem (9) drives the sealing valve core (2) to move and disengage from the throttle valve seat (3), so that the medium can also pass through the axial direction. The flow outlet (32) flows out; the second sealing valve cavity (5) is provided with a flow hole valve seat (7) and a dynamic valve core (6); an abutment rod (26) with an externally sleeved spring element (27) extends from the lower end of the sealing valve core (2), and the bottom end of the abutment rod (26) abuts against the back of the dynamic valve core (6) to form a limit on its movement; in the closed state, the end of the abutment rod (26) abuts against the back of the dynamic valve core (6) to press the dynamic valve core (6) onto the flow hole valve seat (7) to form a third sealing structure; in the self-pressure open state, the valve rod (9) drives the sealing valve core (2) to move, the abutment rod (26) no longer abuts, and the spring element (27) springs back. The dynamic valve core (6) is pressed down to provide a dynamic sealing flow channel that adapts to changes in medium pressure. The bottom of the sealing valve core (2) is also equipped with a top spring (28) that pushes the sealing valve core (2) toward the throttle valve seat (3). Under high temperature and open flame conditions, the limiting connection structure of the valve stem (9) and the abutment rod (26) fails. When the medium pressure is lower than the critical point A, the top spring (28) pushes the sealing valve core (2) to lock the throttle valve seat (3) to form a fourth sealing structure. When the medium pressure is higher than the critical point A, the medium self-pressurizes and pushes the dynamic valve core (6) to move up and block the lower port of the throttle valve seat (3) to form a fifth sealing structure.

2. The medium self-pressurization sealing regulating valve structure according to claim 1, characterized in that: The double sealing cylinder (21) is a double-layer integrated sleeve. The outer wall of the inner cylinder (212) is attached to the inner wall of the throttle valve seat (3), and the inner wall of the outer cylinder (211) is attached to the outer wall of the throttle valve seat (3) and fully covers the radial hole (31). The axial difference between the end faces of the outer cylinder (211) and the inner cylinder (212) is greater than the diameter of the radial hole (31).

3. The medium self-pressurization sealing regulating valve structure according to claim 1, characterized in that: The spring (27) and top spring (28) are made of high-temperature resistant alloy material, which can withstand high temperature environment and maintain elastic performance unchanged. The spring (27) is pre-compressed and assembled between the abutment rod (26) and the dynamic valve core (6), and the top spring (28) is pre-compressed and assembled between the sealing valve core (2) and the end face of the valve cover (13).

4. The medium self-pressurization sealing regulating valve structure according to claim 1, characterized in that: The upper end of the dynamic valve core (6) is a spherical sealing end (66), and the lower port of the throttle valve seat (3) is provided with a conical sealing surface (65), which can fit with the upper end of the dynamic valve core (6) to achieve sealing and plugging. The lower main body end faces of the dynamic valve core (6) and the sealing valve core (2) are both equipped with concave spherical arc surfaces (67).

5. The medium self-pressurization sealing regulating valve structure according to claim 1, characterized in that: High-temperature tripping connections are provided between the valve stem (9) and the sealing valve core (2) and between the sealing valve core (2) and the abutment rod (26). Under high-temperature conditions, the rigid limiting constraint is automatically released, and the spring (27) and the top spring (28) provide elastic pressure constraint. The high-temperature tripping connection includes an inner hole sleeve structure on the valve stem (9) and the abutment rod (26), including an outer sleeve rod (91), an inner sleeve rod (92) and a radial pin (93). The radial pin (93) is radially inserted to provide axial limiting constraint for both the outer sleeve rod (91) and the inner sleeve rod (92). The radial pin (93) is also used to overcome the axial shear force load transmitted by the sealing valve core (2) and the dynamic valve core (6) driven by the medium when the valve stem (9) raises and lowers the sealing valve core (2).

6. The medium self-pressurization sealing regulating valve structure according to claim 1, characterized in that: The critical point A is set as follows: the elastic parameter of the top spring (28) is matched with the set value, which is to overcome the reaction force of pushing the dynamic valve core (6) against the lower end of the throttle valve seat (3). The critical point A is used for the working condition adaptive double locking seal.

7. The adaptive sealing method for the medium self-pressurization sealing regulating valve structure according to any one of claims 1-6, characterized in that, Including conventional sealing adjustment mode and extreme working condition adaptive sealing mode: Conventional sealing adjustment: The valve stem (9) drives the sealing valve core (2) to rise and fall, and the double sealing cylinder (21) forms the first sealing structure and the second sealing structure to block the medium passage. The valve stem (9) moves to drive the sealing valve core (2) to change the stroke to adjust the medium flow rate. The abutment rod (26) presses against the dynamic valve core (6) to form the third sealing structure. After the abutment rod (26) is released, the third sealing structure can also rely on the spring (27) to elastically push the dynamic valve core (6) to form the medium pressure opening valve dynamic adjustment; Extreme low pressure sealing: The high temperature causes the mechanical limit of the sealing valve core (2) and the dynamic valve core (6) to fail. The medium pressure is lower than the critical point A. The medium pressure is greater than the weight sealing force of the dynamic valve core (6) and less than the pressure that pushes the dynamic valve core (6) to move up to block the lower port of the throttle valve seat (3). At this time, the dynamic valve core (6) fails to seal the second sealing valve chamber (5). ) does not have a seal. At the same time, based on the valve stem (9) losing the mechanical limit constraint on the sealing valve core (2), the sealing valve core (2) moves towards the direction of fitting the throttle valve seat (3) with the weight and the pushing force of the top spring (28). After overcoming the medium pressure by the weight and the elastic force of the top spring (28), the fourth sealing structure is formed, and the passive sealing lock is completed. Extreme high pressure seal: The high temperature causes the mechanical limit of the sealing valve core (2) and the dynamic valve core (6) to fail. The medium pressure is higher than the critical point A. The medium pressure is already greater than the sealing valve core (2) with the weight and the pushing force of the top spring (28). At this time, the first sealing valve cavity (4) no longer has a seal. However, the high medium pressure also makes the medium pressure itself complete the pushing of the dynamic valve core (6) to move up and block the lower port of the throttle valve seat (3). Based on the greater the medium pressure, the stronger the sealing clamping force, the fifth sealing structure is formed by the medium self-pressurization, and the passive sealing lock is completed.

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