Zero-leak hard seal globe valve

Abstract

This application relates to the field of gate valve technology, and provides a zero-escape hard-seal gate valve. The zero-escape hard-seal gate valve includes a valve body, valve cover, valve stem, connecting sleeve, bellows, valve disc, packing assembly, packing gland, and pre-tightening mechanism. A hard sealing surface is welded to the inner side of the flow channel of the valve body. The valve cover is mounted on the valve body, and an annular groove is formed inside the valve cover, with a guide portion within the annular groove. An assembly opening is formed at the lower end of the valve cover. The valve stem passes through the valve cover and can move up and down along the central axis of the valve cover. The connecting sleeve is fixed to the assembly opening. The upper end of the bellows is fixed to the connecting sleeve, and the lower end is fixed to the valve disc. The valve disc is located at the lower end of the valve stem. The packing assembly is located inside the valve cover. The packing gland is located on the valve cover. The pre-tightening mechanism includes an elastic pre-tightening element and a pressure self-tightening element. The zero-escape hard-seal gate valve provided by this application improves the problem that due to the long-term idle and deterioration of the backup packing, it cannot respond in time to form an effective seal when the bellows ruptures.

Description

Technical Field

[0001] This application relates to the field of gate valve technology, and in particular to a zero-escape hard-seal gate valve. Background Technology

[0002] Zero-escape hard-seal gate valves are widely used in petroleum, chemical, and power industries where high sealing safety and environmental protection requirements are necessary. They are primarily used to achieve shut-off control of the media passage and zero-escape sealing along the valve stem. A typical zero-escape hard-seal gate valve includes a valve body, valve cover, valve stem, bellows, valve disc, packing assembly, and packing gland. The bellows serves as the primary sealing element, with its upper end fixedly connected to the valve cover and its lower end fixedly connected to the valve stem, forming a closed metal cavity that completely isolates the media outside the bellows, thus achieving zero-escape sealing at the valve stem. The packing assembly serves as a backup seal, positioned above the bellows and pressed tightly by the packing gland. When the bellows is intact, the packing assembly does not bear media pressure and serves only as a backup. If the bellows ruptures unexpectedly, the media propagates upwards along the valve stem, and the packing assembly is pressed tightly by the media pressure, forming a second line of defense to prevent media leakage.

[0003] However, existing zero-escape hard-seal gate valves suffer from unstable packing seal reliability during long-term operation. Specifically, the backup packing is in a non-working, pressureless, and idle state for extended periods. Its materials (such as flexible graphite and PTFE) are prone to hardening, loss of elasticity, and plastic deformation under prolonged pressureless conditions. When the bellows ruptures unexpectedly due to fatigue or other reasons, the medium propagates instantaneously upwards along the valve stem. The already deteriorated packing cannot respond quickly enough to form an effective seal, causing the medium to leak to the outside of the valve before the packing is compressed. This failure mode poses serious safety hazards under high temperature, high pressure, or when conveying flammable or explosive media. Summary of the Invention

[0004] This application provides a zero-escape hard-seal shut-off valve, which can improve the technical problem in related technologies where the backup packing deteriorates due to long-term idleness, and cannot respond in time to form an effective seal when the bellows ruptures, thus leading to media leakage.

[0005] In a first aspect, embodiments of this application provide a zero-escape hard-seal shut-off valve, comprising: The valve body has a hard sealing surface welded to the inner side of the flow channel; A valve cover is provided on the valve body. An annular groove is provided inside the valve cover, and a guide part is provided in the annular groove. An assembly opening is provided at the lower end of the valve cover. A valve stem passes through the valve cover and can move up and down along the central axis of the valve cover; The connecting sleeve is fixed to the assembly opening; A bellows, the upper end of which is fixed to the connecting sleeve; A valve disc is located at the lower end of the valve stem, and the valve disc is sealed to the hard sealing surface. The lower end of the bellows is fixed to the valve disc. A packing assembly is disposed inside the valve cover, and the packing assembly is located above the bellows; the guide portion is disposed between the upper end of the bellows and the lower end of the packing assembly. A packing gland is provided on the valve cover, and the packing gland presses against the packing assembly; A pre-tightening mechanism, comprising an elastic pre-tightening element and a pressure self-tightening element; the lower end of the elastic pre-tightening element abuts against the upper end of the connecting sleeve, the upper end of the elastic pre-tightening element abuts against the lower end of the pressure self-tightening element, and the upper end of the pressure self-tightening element abuts against the lower end of the packing assembly; the pressure self-tightening element is connected to the guide portion.

[0006] The technical solutions described in this application embodiment have at least the following technical effects: The zero-escape hard-seal shut-off valve provided in this application embodiment, under normal conditions where the bellows is intact, the elastic pre-tightening component outputs a stable axial pre-tightening force through the connecting sleeve, which is uniformly transmitted and tightened through the pressure self-tightening component to the packing assembly, and a conventional axial seal is formed by the packing assembly. The bellows extends and contracts axially with the valve disc to ensure a zero-escape seal in daily life. When the bellows ruptures, the medium pressure acts directly on the bottom of the pressure self-tightening element. The pressure self-tightening element deforms along the inclined surface of the guide section, radially tightening and gripping the valve stem to form an emergency radial seal. At the same time, the pre-tightening mechanism continuously maintains the axial compression of the packing assembly, achieving a dynamic adaptive sealing effect where the greater the pressure, the tighter the seal. By utilizing the force conversion of the inclined surface, the medium pressure is converted into the valve stem clamping force. This simultaneously constructs a double sealing defense line of axial compression of the packing assembly and radial clamping of the pressure self-tightening element. Even if a single seal fails, the sealing effectiveness can still be guaranteed. Furthermore, the pressure self-tightening element acts as a front barrier against medium impact, reducing direct contact between the packing assembly and the medium, thus significantly extending its service life. This effectively improves the technical problem in related technologies where the backup packing deteriorates due to long-term idleness and cannot respond in time to form an effective seal when the bellows ruptures, leading to medium leakage. This significantly improves the sealing reliability and operational safety of the valve.

[0007] Secondly, embodiments of this application provide an assembly method for a zero-escape hard-seal shut-off valve, applied to the zero-escape hard-seal shut-off valve described in the first aspect above, comprising: The pressure self-tightening member is assembled into the annular groove through the assembly opening, and the pressure self-tightening member cooperates with the guide portion. The elastic preload is assembled into the annular groove through the assembly opening, with the upper end of the elastic preload abutting against the lower end of the pressure self-tightening member. Based on the guide portion, the control assembly actuator performs adaptive coaxial alignment between the pressure self-tightening member and the annular groove, and calibrates the preload of the elastic preload member; The connecting sleeve is fixedly installed at the assembly opening, and the lower end of the elastic preload abuts against the upper end of the connecting sleeve; The packing assembly is assembled into the interior of the valve cover, with the lower end of the packing assembly abutting against the upper end of the pressure self-tightening member; The packing gland is assembled onto the valve cover and the packing assembly is pressed to obtain a pre-assembled valve cover assembly. The valve disc is placed at the lower end of the valve stem, the lower end of the bellows is fixed to the valve disc, and the valve stem is assembled into the interior of the valve body. The valve disc and the hard sealing surface form a sealing fit. The valve cover pre-assembly assembly is placed on the valve body, the valve stem passes through the valve cover pre-assembly assembly along the central axis of the valve cover, and the upper end of the bellows is fixed to the connecting sleeve.

[0008] The technical solutions described in this application embodiment have at least the following technical effects: The assembly method of the zero-escape hard-seal gate valve provided in this application embodiment involves first inserting the pressure self-tightening component and the elastic pre-tightening component into the annular groove through the assembly opening. Initial fitting is achieved using the guide portion within the annular groove. Then, the assembly actuator achieves adaptive coaxial alignment between the pressure self-tightening component and the annular groove and calibrates the pre-tightening load of the elastic pre-tightening component. Next, the connecting sleeve is fixedly installed at the assembly opening and limits the pre-tightening mechanism. Subsequently, the valve cover pre-installation of the packing assembly and packing gland is completed. Simultaneously, the valve stem and valve disc are assembled on the valve body side, and the lower end of the bellows is fixed. Finally, the valve cover is assembled, and the upper end of the bellows is fixed. By ensuring the assembly accuracy and fitting stability of core components such as the pre-tightening mechanism, packing assembly, and bellows, this method effectively improves the technical problem of media leakage caused by the inability to form an effective seal in time when the bellows ruptures due to the long-term idle deterioration of the backup packing. This enhances the sealing safety and reliability of the zero-escape hard-seal gate valve. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic diagram of the zero-escape hard-seal shut-off valve provided in an embodiment of this application; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 A schematic flowchart illustrating the assembly method of the zero-escape hard-seal shut-off valve provided in the embodiments of this application; Figure 4 A schematic diagram illustrating the implementation process of step S3000 in the assembly method of the zero-escape hard-seal shut-off valve provided in the embodiments of this application; Figure 5 A schematic diagram illustrating the implementation process of step S3200 in the assembly method of the zero-escape hard-seal shut-off valve provided in the embodiments of this application; Figure 6 The figures show the performance test results of an embodiment and a comparative example of the assembly method for the zero-escape hard-seal shut-off valve provided in this application.

[0011] The following are the labeling elements in the figure: 100. Zero-escape hard-seal gate valve; 10. Valve body; 11. Valve cover; 111. Annular groove; 1111. Guide section; 12. Valve stem; 13. Connecting sleeve; 14. Bellows; 15. Valve disc; 16. Packing assembly; 161. Lower packing pad; 162. Packing body; 163. Packing gland; 17. Packing gland; 18. Pre-tightening mechanism; 181. Elastic pre-tightening element; 182. Pressure self-tightening element. Detailed Implementation

[0012] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0013] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. The terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0014] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0015] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0016] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0017] In this application, "and / or" is merely a way of describing the relationship between related objects, indicating that three relationships can exist; for example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0018] It should be noted that in this application, the words "in some embodiments," "exemplarily," and "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "in some embodiments," "exemplarily," or "for example" should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of words such as "in some embodiments," "exemplarily," and "for example" is intended to present related concepts in a specific manner, meaning that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of this application. The appearance of the above words in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0019] Zero-escape hard-seal gate valves are widely used in petroleum, chemical, and power industries where high sealing safety and environmental protection requirements are necessary. They are primarily used to achieve shut-off control of the media passage and zero-escape sealing along the valve stem. A typical zero-escape hard-seal gate valve includes a valve body, valve cover, valve stem, bellows, valve disc, packing assembly, and packing gland. The bellows serves as the primary sealing element, with its upper end fixedly connected to the valve cover and its lower end fixedly connected to the valve stem, forming a closed metal cavity that completely isolates the media outside the bellows, thus achieving zero-escape sealing at the valve stem. The packing assembly serves as a backup seal, positioned above the bellows and pressed tightly by the packing gland. When the bellows is intact, the packing assembly does not bear media pressure and serves only as a backup. If the bellows ruptures unexpectedly, the media propagates upwards along the valve stem, and the packing assembly is pressed tightly by the media pressure, forming a second line of defense to prevent media leakage.

[0020] However, existing zero-escape hard-seal gate valves suffer from unstable packing seal reliability during long-term operation. Specifically, the backup packing is in a non-working, pressureless, and idle state for extended periods. Its materials (such as flexible graphite and PTFE) are prone to hardening, loss of elasticity, and plastic deformation under prolonged pressureless conditions. When the bellows ruptures unexpectedly due to fatigue or other reasons, the medium propagates instantaneously upwards along the valve stem. The already deteriorated packing cannot respond quickly enough to form an effective seal, causing the medium to leak to the outside of the valve before the packing is compressed. This failure mode poses serious safety hazards under high temperature, high pressure, or when conveying flammable or explosive media.

[0021] Based on this, in order to improve the problem in the related technology that the backup packing deteriorates due to long-term idleness and cannot respond in time to form an effective seal when the bellows breaks, thus leading to media leakage, the embodiments of this application provide the following solution.

[0022] Please refer to the following: Figure 1 and Figure 2 This application provides a zero-escape hard-seal stop valve 100, which includes a valve body 10, a valve cover 11, a valve stem 12, a connecting sleeve 13, a bellows 14, a valve disc 15, a packing assembly 16, a packing gland 17, and a pre-tightening mechanism 18, wherein: The inner side of the flow channel of the valve body 10 is welded to form a hard sealing surface.

[0023] The valve cover 11 is placed on the valve body 10. The valve cover 11 has an annular groove 111 inside, and a guide part 1111 is provided in the annular groove 111. The lower end of the valve cover 11 has an assembly opening.

[0024] The valve stem 12 passes through the valve cover 11 and can move up and down along the central axis of the valve cover 11.

[0025] The connecting sleeve 13 is fixed to the assembly opening.

[0026] The upper end of the bellows 14 is fixed to the connecting sleeve 13.

[0027] The valve disc 15 is located at the lower end of the valve stem 12. The valve disc 15 is sealed to the hard sealing surface. The lower end of the bellows 14 is fixed to the valve disc 15.

[0028] The packing assembly 16 is located inside the valve cover 11 and is situated above the bellows 14; the guide portion 1111 is located between the upper end of the bellows 14 and the lower end of the packing assembly 16.

[0029] The packing gland 17 is located on the valve cover 11 and presses the packing assembly 16.

[0030] The pre-tightening mechanism 18 includes an elastic pre-tightening member 181 and a pressure self-tightening member 182; the lower end of the elastic pre-tightening member 181 abuts against the upper end of the connecting sleeve 13, the upper end of the elastic pre-tightening member 181 abuts against the lower end of the pressure self-tightening member 182, and the upper end of the pressure self-tightening member 182 abuts against the lower end of the packing assembly 16; the pressure self-tightening member 182 is connected to the guide portion 1111.

[0031] It can be understood that the valve body 10 is the pressure-bearing base of the zero-escape hard-seal shut-off valve 100, the flow channel is the passage for medium flow, and the hard sealing surface is a sealing working surface formed by a welding process on the inner side of the flow channel. The welding material can be wear-resistant and corrosion-resistant materials such as Stellite alloy and cobalt-based hard alloy. The valve cover 11 is a cover component that cooperates with the valve body 10 to form a closed inner cavity. It is bolted to the valve body 10 to form a closed inner cavity and is used to encapsulate all internal components. The annular groove 111 is a groove integrally machined inside the valve cover 11, used to limit the assembly of the pressure self-tightening component 182 and the elastic pre-tightening component 181. The guide part 1111 is a radial positioning fit structure between the pressure self-tightening component 182 and the annular groove 111. For example, it can be a mating surface where the pressure self-tightening component 182 and the annular groove 111 fit together, used to achieve coaxial alignment and force transmission between the pressure self-tightening component 182 and the annular groove 111. The assembly opening is an opening made for the disassembly, assembly, and processing of the internal components of the valve cover 11.

[0032] The valve stem 12 is a rod-shaped component that transmits the opening and closing driving force, and the central axis of the valve cover 11 is the reference axis for the up and down movement of the valve stem 12. The connecting sleeve 13 is a transition support component that is fixedly sealed at the assembly opening. It serves as both a fixed mounting base for the upper end of the bellows 14 and a bearing reference for the lower end of the elastic preload 181, thereby achieving stable support and vertical transmission of the preload force.

[0033] The bellows 14 is a flexible metal sealing component, serving as the main sealing element of the zero-escape hard-seal gate valve 100. It is an integral, expandable corrugated metal tube, with its upper end fixed to the connecting sleeve 13 and its lower end fixed to the valve disc 15. It expands and contracts with the valve stem 12 as it moves up and down, completely enclosing the valve stem 12 to prevent media leakage. The valve disc 15 is a sealing and opening / closing element used to control the valve's on / off state. It is fixed to the bottom end of the valve stem 12 and can, for example, employ a conical or planar sealing disc structure, fitting against the hard sealing surface of the valve body 10 to achieve the main seal.

[0034] The packing assembly 16 is a backup sealing member used to form an auxiliary seal in the event of bellows 14 failure. The packing gland 17 is an axial pressure-applying member located on top of the valve cover 11, which applies axial pressure to the packing assembly 16 by bolt tightening.

[0035] The preload mechanism 18 is an elastic preload force transmission structure composed of an elastic preload element 181 and a pressure self-tightening element 182 arranged vertically. The elastic preload element 181 is an elastic component that provides elastic preload force, such as a cylindrical helical spring, a disc spring assembly, or a wave spring. The pressure self-tightening element 182 is a pressure-bearing transmission component that transmits preload force and is adapted to the annular groove 111. It is used to uniformly transmit the force of the elastic preload element 181 to the packing assembly 16, such as a wedge-shaped self-tightening ring. The elastic preload element 181 and the pressure self-tightening element 182 abut vertically to form a complete force transmission path.

[0036] As can be seen from the above, the zero-escape hard seal shut-off valve 100 provided in this application embodiment, under the normal condition of the bellows 14 being intact, the elastic pre-tightening member 181 outputs a stable axial pre-tightening force through the connecting sleeve 13, which is uniformly transmitted and pressed into the packing assembly 16 through the pressure self-tightening member 182, and a conventional axial seal is formed by the packing assembly 16. The bellows 14 extends and contracts axially with the valve disc 15 to ensure daily zero-escape sealing. When the bellows 14 is damaged, the medium pressure acts directly on the bottom of the pressure self-tightening element 182. The pressure self-tightening element 182 deforms along the inclined surface of the guide portion 1111, radially tightening and gripping the valve stem 12 to form an emergency radial seal. At the same time, the pre-tightening mechanism 18 continuously maintains the axial compression of the packing assembly 16, which can achieve a dynamic adaptive sealing effect where the greater the pressure, the tighter the seal. By using the force conversion of the inclined surface, the medium pressure is converted into the valve stem clamping force. At the same time, a double sealing defense line is constructed with the axial compression of the packing assembly 16 and the radial clamping of the pressure self-tightening element 182. Even if a single seal fails, the sealing effectiveness can still be guaranteed. Moreover, the pressure self-tightening element 182 blocks the impact of the medium in front, reducing the direct contact of the packing assembly 16 with the medium erosion and greatly extending its service life. It effectively improves the technical problem in related technologies where the backup packing deteriorates due to long-term idleness and cannot respond in time to form an effective seal when the bellows 14 is broken, resulting in the leakage of the medium. This greatly improves the sealing reliability and operational safety of the valve.

[0037] In some embodiments, the guide portion 1111 is a slope-fitting structure, which includes a first slope provided on the outer peripheral surface of the pressure self-tightening member 182, and a second slope provided on the inner peripheral surface of the annular groove 111 that fits with the first slope.

[0038] It can be understood that the inclined surface mating structure is a structural form that achieves mating through two mutually fitting inclined surfaces, relying on the contact of the two inclined surfaces to achieve radial positioning and axial force transmission. The first inclined surface is an inclined mating surface machined on the outer circumferential surface of the pressure self-tightening component 182, and the second inclined surface is an inclined mating surface machined on the inner circumferential surface of the annular groove 111. The inclination angles of the first and second inclined surfaces are the same, and the two can completely fit together. The inclined surface mating structure belongs to a mating structure that combines radial positioning and axial force transmission. The inclination angle can be set to 30°, 45°, 60°, etc., according to assembly requirements.

[0039] With this configuration, the inclined mating structure can achieve radial alignment between the pressure self-tightening element 182 and the annular groove 111 by using the fitting inclined surfaces, so that the pressure self-tightening element 182 always remains coaxial with the valve cover 11, and the pre-tightening force of the elastic pre-tightening element 181 is evenly transmitted to the packing assembly 16, so that the force on each part of the backup packing is consistent, reducing the deterioration caused by uneven force, and providing structural support for timely formation of a uniform and effective seal when the bellows 14 ruptures.

[0040] Optionally, in some embodiments, the pressure self-tightening element 182 is a wedge-shaped self-tightening ring, and the first inclined surface is an inclined surface integrally formed on the outer peripheral surface of the wedge-shaped self-tightening ring.

[0041] It is understandable that the wedge-shaped self-tightening ring is a solid ring-shaped part with an inclined surface on its outer circumference, and has a central through hole for the valve stem 12 to pass through. The whole structure is a one-piece structure without splicing or welding. The one-piece inclined surface is formed directly on the outer circumference of the wedge-shaped self-tightening ring by machining, and is the same as the component body.

[0042] With this configuration, the wedge-shaped self-tightening ring and the inclined surface of the annular groove 111 cooperate, resulting in higher structural strength and more stable fit accuracy. This allows the pre-tightening force to be uniformly transmitted to the packing assembly 16 without loss, ensuring that the backup packing maintains a stable pre-tight fit for a long time. This reduces the probability of the backup packing hardening, deformation, or other deterioration problems due to idleness. In the event of bellows 14 failure, the packing can be quickly compressed to form a seal, effectively reducing the risk of media leakage.

[0043] Optionally, the elastic preload 181 is a cylindrical helical spring, a disc spring assembly, or a wave spring, and the elastic preload 181 is sleeved on the outside of the valve stem 12.

[0044] It is understandable that a cylindrical helical spring is a cylindrical helical wound elastic element, made of continuously helically wound metal wire, which can provide stable axial elastic force. A disc spring assembly is an elastic component formed by stacking multiple cup-shaped disc springs, and is a commonly used high-load elastic element in high-pressure valves. A wave spring is a continuous wave-shaped annular elastic element, a thin annular elastic element, suitable for installation in confined spaces. The elastic preload element 181 being sleeved on the outside of the valve stem 12 means that the elastic preload element 181 surrounds the valve stem 12, with a gap between the central through hole and the valve stem 12, not directly contacting the valve stem 12, and only undergoing axial expansion and contraction.

[0045] This configuration allows for the flexible selection of suitable elastic pre-tightening elements 181 for zero-escape hard-seal shut-off valves 100 of different specifications and operating conditions, continuously providing stable and adjustable axial pre-tightening force to the pressure self-tightening element 182, ensuring that the packing assembly 16 is always in a moderate pre-tightening state, reducing the deterioration problems such as hardening, embrittlement, and failure of the backup packing due to long-term idleness without pre-tightening force, and ensuring that the backup sealing function can be triggered in time when the bellows 14 ruptures.

[0046] For example, please refer to Figure 1 and Figure 2 The packing assembly 16 includes a lower packing pad 161, a packing body 162, and a packing sleeve 163 arranged sequentially from bottom to top; the upper end of the pressure self-tightening member 182 abuts against the lower packing pad 161, and the packing gland 17 abuts against the packing sleeve 163 and presses the packing body 162.

[0047] It is understood that the lower packing gasket 161 is an annular sheet-shaped support gasket, generally made of wear-resistant sealing materials such as polytetrafluoroethylene (PTFE) or flexible graphite. It is located at the bottom of the packing body 162 to receive and evenly distribute the pre-tightening force transmitted by the pressure self-tightening element 182. The packing body 162 is an annular sealing packing, made of sealing materials such as flexible graphite or carbon fiber braid, and is the core working part of the backup seal. The packing sleeve 163 is an annular sleeve-shaped pressure-applying element, made of metal or wear-resistant engineering plastic, located at the top of the packing body 162, used to evenly transmit the axial pressure of the packing gland 17 to the packing body 162. The lower packing gasket 161, packing body 162, and packing sleeve 163 are stacked and assembled sequentially from bottom to top, forming a layered packing seal structure.

[0048] With this configuration, the packing assembly 16 can improve the reliability and stability of the backup seal. The pressure self-tightening element 182 pushes the packing body 162 evenly through the lower packing pad 161, so that the packing body 162 always maintains a uniform pre-tight sealing state, effectively improving the deterioration problem caused by long-term idleness of the backup packing. When the bellows 14 ruptures, it can quickly form a complete backup seal, blocking the path of medium leakage along the valve stem 12.

[0049] Please see Figure 3This application also provides an assembly method for a zero-escape hard-seal shut-off valve 100, which includes: S1000, through the assembly opening, the pressure self-tightening member 182 is assembled into the annular groove 111, and the pressure self-tightening member 182 and the guide part 1111 are engaged.

[0050] For example, with the central axis of the valve cover 11 as the positioning reference, the pressure self-tightening member 182 is vertically placed into the annular groove 111 through the assembly opening, so that the outer peripheral structure of the pressure self-tightening member 182 fits the guide part 1111 to complete the inclined surface adaptation positioning, and the pressure self-tightening member 182 is initially aligned and placed in the annular groove 111.

[0051] S2000, through the assembly opening, the elastic preload 181 is assembled into the annular groove 111, and the upper end of the elastic preload 181 abuts against the lower end of the pressure self-tightening member 182.

[0052] For example, the elastic preload 181 is vertically inserted into the annular groove 111 through the assembly opening, so that the upper end face of the elastic preload 181 is smoothly attached to the lower end face of the pressure self-tightening member 182, forming a stable axial abutment structure to ensure that the subsequent preload force can be smoothly transmitted.

[0053] S3000, based on guide part 1111, controls assembly actuator to perform adaptive coaxial alignment of pressure self-tightening member 182 and annular groove 111, and calibrates preload of elastic preload member 181.

[0054] It can be understood that the assembly actuator is a device used to complete the adaptive coaxial alignment adjustment of the pressure self-tightening component 182 and the preload calibration of the elastic preload component 181. It includes a multi-degree-of-freedom drive module, a flexible clamping module, and an axial pressure application module. Among them, the multi-degree-of-freedom drive module is the core power component, including a servo motor, a precision transmission screw, and a linear guide. The output end of the servo motor is coaxially connected to the precision transmission screw, and the linear guide is arranged parallel to the precision transmission screw. The whole assembly is arranged above the valve cover 11 assembly station to provide multi-dimensional driving force for radial movement, angular deflection, and axial lifting.

[0055] The flexible clamping module includes a pneumatic gripper and a flexible anti-slip pad. The pneumatic gripper is fixedly connected to the execution end of the multi-degree-of-freedom drive module. The flexible anti-slip pad is fitted to the inner clamping side of the pneumatic gripper. The flexible clamping module is located directly above the internal assembly area of ​​the valve cover 11 and is used to flexibly clamp the pressure self-tightening member 182 and transmit attitude adjustment actions. The axial pressure application module includes a pressure loading rod and a load transmission connector. The pressure loading rod is coaxially arranged with the multi-degree-of-freedom drive module. The load transmission connector is fixed to the bottom end of the pressure loading rod. The axial pressure application module is located directly above the elastic preload member 181 and is used to accurately apply axial pressure to calibrate the preload load.

[0056] During operation, the servo motor drives the precision transmission screw to move, causing the linear guide and the actuator to produce multi-dimensional movements of radial movement, angular deflection, and axial lifting. The pneumatic gripper flexibly clamps the pressure self-tightening component 182 through the flexible anti-slip pad on the inner side. With the movement of the multi-degree-of-freedom drive module, the posture of the pressure self-tightening component 182 is adjusted to achieve coaxial alignment. At the same time, the pressure loading rod applies precise axial pressure to the elastic pre-tightening component 181 through the load transmission joint at the bottom end. In conjunction with the movement of the multi-degree-of-freedom drive module, the pre-tightening load calibration of the elastic pre-tightening component 181 is completed.

[0057] Adaptive coaxial alignment is an assembly action that automatically adjusts the posture of the components based on the positioning reference so that the pressure self-tightening member 182 coincides with the central axis of the annular groove 111. The preload is the magnitude of the elastic force generated after the elastic preload member 181 is compressed.

[0058] For example, when completing the adaptive coaxial alignment and preload calibration design for this step, a comprehensive optimization is performed from multiple dimensions, including mechanical matching, structural parameters, material compatibility, and clearance control: First, the wedge angle of the guide section 1111 is optimized based on the law of inclined plane force decomposition, and the optimal inclination angle range that balances force transmission efficiency and anti-locking characteristics is selected, thus laying a solid structural foundation for the smooth conversion of medium pressure into radial force to clamp the valve stem 12 after the bellows 14 is damaged; then, based on the reasonable clamping force required for normal packing sealing, the elastic modulus, wire diameter specifications, and assembly compression stroke of the elastic preload element 181 are calculated in reverse, thereby calibrating the standard preload that needs to be calibrated during assembly, so that the force transmitted by the elastic preload element 181 under normal working conditions can maintain the stability of the packing seal without causing the pressure self-tightening element 182 to be subjected to overload stress for a long time and produce plastic deformation; at the same time, the fitting clearance between the pressure self-tightening element 182 and the valve stem 12 is finely set, preload A reasonable allowance is provided for the elastic deformation of the matching material and the normal working allowance of the valve stem 12, so that the pressure self-tightening component 182 can be uniformly fitted to the outer wall of the valve stem 12 after contraction during emergency sealing, and the normal operation of the valve stem 12 is not affected. The pressure self-tightening component 182 is made of a metal substrate with controllable elasticity and wear resistance. With the friction reduction and lubrication treatment of the contact surface, it not only reduces the frictional resistance during assembly and alignment and improves the calibration accuracy, but also relies on the elastic threshold of the material itself to limit the deformation range. Combined with the limiting protection of the guide part 1111, it reduces the excessive expansion and cracking of the pressure self-tightening component 182 under high pressure impact. All core parameters are also checked through basic mechanical correlation to form an adaptation system, so that the preload, inclined plane angle, fit clearance and material performance are coordinated with each other, which not only ensures accurate calibration during the assembly stage, but also meets the requirements of valve normal operation force safety and dynamic clamping and sealing effect under fault conditions.

[0059] In some embodiments, please refer to Figure 4S3000, the control assembly actuator performs adaptive coaxial alignment of the pressure self-tightening member 182 and the annular groove 111, including: S3100 collects in real time the coaxial attitude data of the pressure self-tightening member 182 relative to the annular groove 111 through the position monitoring unit.

[0060] The position monitoring unit is a sensing and detection component used to detect the position, orientation, and axial deviation of a component. It includes a laser displacement sensor, a visual image acquisition camera, and a data processing module. The laser displacement sensor is symmetrically arranged on the outer periphery of the valve cover 11 assembly station. The visual image acquisition camera faces the mating area between the pressure self-tightening member 182 and the annular groove 111. The data processing module is electrically connected to the laser displacement sensor and the visual image acquisition camera. During operation, the laser displacement sensor collects the radial distance signal between the outer periphery of the pressure self-tightening member 182 and the inner periphery of the annular groove 111 in real time. The visual image acquisition camera simultaneously captures the axial mating posture image of the two components. The data processing module receives and analyzes the radial distance signal and the axial mating posture image, ultimately outputting coaxial posture data reflecting the pressure self-tightening member 182 relative to the annular groove 111.

[0061] Coaxial attitude data is a set of data reflecting attitude information such as the offset and tilt of the central axis of the pressure self-tightening component 182 relative to the central axis of the annular groove 111.

[0062] For example, laser displacement sensors symmetrically arranged on the outer periphery of the valve cover 11 assembly station are used to detect the radial distance between the outer periphery of the pressure self-tightening component 182 and the inner periphery of the annular groove 111 in real time and output analog electrical signals. At the same time, a visual image acquisition camera facing the mating area captures the mating posture image of the pressure self-tightening component 182 and the annular groove 111. The data processing module first converts the analog electrical signals into digital distance values, and then performs edge recognition and contour extraction on the posture image to accurately locate the central axis of the pressure self-tightening component 182 and the annular groove 111. Subsequently, the digital distance values ​​and the axis positioning results are fused and calculated to obtain the axial offset and tilt angle of the pressure self-tightening component 182 relative to the annular groove 111.

[0063] S3200, determine the coaxial deviation value of the pressure self-tightening element 182 relative to the annular groove 111 based on the coaxial attitude data.

[0064] It is understandable that the coaxial deviation value is a numerical indicator used to quantify the degree of misalignment between the central axis of the pressure self-tightening component 182 and the annular groove 111, and is the core basis for adjusting the assembly posture.

[0065] In one possible implementation, please refer to Figure 5 S3200, based on coaxial attitude data, determines the coaxial deviation value of the pressure self-tightening element 182 relative to the annular groove 111, including: S3210, based on the central axis of the annular groove 111, establish a reference coordinate system for coaxial alignment, and calibrate the standard assembly posture parameters under the reference coordinate system.

[0066] It can be understood that the reference coordinate system is a spatial rectangular coordinate system established with the central axis of the annular groove 111 as the reference axis, and the standard assembly posture parameters are the ideal posture parameter set in the reference coordinate system when the pressure self-tightening component 182 and the annular groove 111 are completely coaxial.

[0067] For example, a spatial coordinate system is established with the central axis of the annular groove 111 as the Z-axis and the plane perpendicular to the Z-axis as the XY plane, and the ideal position and angle parameters of the pressure self-tightening member 182 in the reference coordinate system are calibrated when they are completely coaxial.

[0068] S3220, based on the assembly deformation characteristics of the elastic preload 181, the coaxial attitude data is compensated and corrected to obtain the corrected coaxial attitude data.

[0069] It is understandable that the assembly deformation characteristics are the rules and features of the deformation generated by the elastic preload 181 during the assembly compression process. The compensation correction is the calculation and processing process to reduce the interference of the elastic preload 181 deformation on the attitude data detection. The corrected coaxial attitude data is the accurate attitude data after eliminating deformation interference.

[0070] In one possible implementation, please refer to Figure 5 S3220, based on the assembly deformation characteristics of the elastic preload 181, the coaxial attitude data is compensated and corrected to obtain the corrected coaxial attitude data, including: S3221, Based on the assembly deformation characteristics of the elastic preload 181, determine the assembly deformation parameters corresponding to the elastic preload 181.

[0071] It can be understood that the assembly deformation parameters are a set of characteristic parameters used to characterize the degree and law of compression deformation of the elastic preload 181 assembly.

[0072] For example, based on the elastic structure characteristics and compression deformation law of the elastic preload 181 itself, characteristic parameters that can reflect its deformation state are extracted. For example, for a cylindrical helical spring, the elastic coefficient is an inherent characteristic parameter that characterizes the magnitude of the elastic force corresponding to the unit compression amount, and the compression stroke is the axial displacement of the spring during assembly. First, the actual compression stroke of the cylindrical helical spring in the current assembly state is collected, and then combined with the inherent elastic coefficient of the cylindrical helical spring, based on the corresponding correlation between elastic deformation and compression amount, parameters that can directly reflect the actual assembly deformation state, such as the current elastic deformation force and deformation displacement deviation of the spring, are calculated. These parameters are the corresponding assembly deformation characteristic parameters.

[0073] S3222, determine the compensation coefficient corresponding to the coaxial attitude data based on the assembly deformation parameters.

[0074] It is understandable that the compensation coefficient is a proportional adjustment coefficient used to reduce the impact of the deformation of the elastic preload 181 on the attitude data, and it is a key calculation parameter for achieving data correction.

[0075] For example, based on the type, elastic properties, and standard assembly conditions of the elastic preload 181, a mapping relationship library of deformation parameters and compensation coefficients is established in advance through theoretical calculations and experimental calibration. This mapping relationship library is a calibration data set. After determining the assembly deformation parameters, the currently acquired assembly deformation parameters are substituted into this mapping relationship library, and a compensation coefficient uniquely corresponding to the current assembly deformation state is matched through data comparison or fitting calculation.

[0076] S3223, the coaxial attitude data is corrected and calculated based on the compensation coefficient to obtain the corrected coaxial attitude data.

[0077] For example, the collected coaxial attitude data is processed with the compensation coefficient to reduce the data deviation caused by the deformation of the elastic preload 181, and the corrected coaxial attitude data is obtained. For example, the coaxial attitude data and the compensation coefficient are multiplied to obtain the corrected accurate attitude data.

[0078] By adopting the above steps S3221 to S3223, the interference of the assembly deformation of the elastic preload 181 on the coaxial posture detection can be effectively reduced, accurate coaxial posture data can be obtained, providing a reliable basis for subsequent coaxial deviation calculation, ensuring the alignment accuracy of the pressure self-tightening component 182, making the packing assembly 16 more uniformly stressed, and delaying the deterioration of the spare packing when idle.

[0079] S3230, compare and calculate the corrected coaxial posture data with the standard assembly posture parameters to obtain the coaxial deviation value of the pressure self-tightening component 182 relative to the annular groove 111.

[0080] For example, the corrected coaxial attitude data is compared with the standard attitude parameters in the reference coordinate system, and the difference between the two is calculated, which is the quantized coaxial deviation value.

[0081] By adopting the above steps S3210 to S3230, the coaxial deviation between the pressure self-tightening element 182 and the annular groove 111 can be accurately quantified, providing accurate data support for adaptive alignment adjustment, improving assembly coaxiality, and ensuring that the preload is evenly transmitted to the packing assembly 16.

[0082] S3300 controls the assembly actuator to adjust the assembly posture of the pressure self-tightening component 182 according to the coaxial deviation value.

[0083] It can be understood that the assembly posture refers to the assembly state of the pressure self-tightening component 182 inside the valve cover 11, such as its spatial position, tilt angle, and radial position. Adjusting the assembly posture is the action of changing the position of the pressure self-tightening component 182 to make it coaxial with the annular groove 111 based on the coaxial deviation value.

[0084] For example, the assembly actuator drives the pressure self-tightening member 182 to perform radial movement, angle fine adjustment and other actions based on the calculated coaxial deviation value, so that the central axis of the pressure self-tightening member 182 coincides with the central axis of the annular groove 111.

[0085] By adopting the above steps S3100 to S3300, high-precision adaptive coaxial alignment of the pressure self-tightening element 182 and the annular groove 111 is achieved, ensuring the assembly accuracy of the pre-tightening mechanism 18, so that the elastic pre-tightening force is evenly applied to the packing assembly 16, and reducing the deterioration of the backup packing due to uneven force.

[0086] In some embodiments, please refer to Figure 4 S3000, calibrating the preload of the elastic preload 181, including: S3400 collects the actual preload data of the elastic preload member 181 in real time through the load sensing unit.

[0087] The load sensing unit is a sensing and detection component used to detect the magnitude of the force applied by the elastic member. It includes a strain gauge pressure sensor, a signal conditioning module, and a data acquisition module. The strain gauge pressure sensor is positioned between the axial force-bearing end face of the elastic preload member 181 and the load transmission joint of the assembly actuator. The signal conditioning module is electrically connected to the strain gauge pressure sensor, and the data acquisition module is electrically connected to the signal conditioning module. During operation, the strain gauge pressure sensor directly senses the axial force generated by the compression of the elastic preload member 181 and outputs a weak electrical signal. The signal conditioning module amplifies, filters, and reduces noise in this signal. The data acquisition module converts the processed analog signal into a standard digital signal, ultimately forming actual preload data that can be directly used for calculation and comparison.

[0088] The actual preload data is the actual force data generated by the elastic preload member 181 under the current compression state.

[0089] For example, a strain gauge pressure sensor is placed between the upper end face of the elastic preload 181 and the load transmission joint of the assembly actuator, so that the strain gauge pressure sensor directly bears the axial compressive force of the elastic preload 181. The strain gauge pressure sensor converts the force into a weak electrical signal and transmits it to the signal conditioning module. After amplification, filtering and noise reduction, the signal is converted into the actual preload value in digital form by the data acquisition module, forming continuous and stable load data.

[0090] S3500 compares the actual preload data with the preset target load data.

[0091] It is understandable that the preset target load data is the ideal preload value that the elastic preload 181 needs to achieve.

[0092] For example, the actual preload data collected in real time is compared with the preset target load data to determine whether the actual preload meets the target requirements.

[0093] S3600 controls the assembly actuator to adjust the pressure applied to the elastic preload 181 based on the comparison results.

[0094] For example, the assembly actuator performs slight compression or release on the elastic preload member 181 based on the comparison between the actual preload data and the preset target load data, so that the actual preload of the elastic preload member 181 matches the preset target load data.

[0095] By adopting the above steps S3400 to S3600, the preload of the elastic preload 181 is accurately calibrated, ensuring that a stable and appropriate preload force is provided to the packing assembly 16, reducing the idle deterioration of the backup packing due to excessive or insufficient preload force, and ensuring that an effective seal can be formed in time when the bellows 14 ruptures.

[0096] S4000, the connecting sleeve 13 is fixedly installed at the assembly opening, and the lower end of the elastic preload 181 abuts against the upper end of the connecting sleeve 13.

[0097] For example, the connecting sleeve 13 is aligned with the assembly opening to complete the alignment assembly and securely fixed, so that the upper end face of the connecting sleeve 13 is smoothly attached to the lower end face of the elastic pretensioner 181, thereby forming a vertical limit lock on the pretensioning mechanism 18 after coaxial calibration and load calibration, and securely sealing the adjusted pretensioning stroke and force state.

[0098] S5000, the packing assembly 16 is assembled into the interior of the valve cover 11, with the lower end of the packing assembly 16 abutting against the upper end of the pressure self-tightening member 182.

[0099] For example, the packing assembly 16 is placed into the internal cavity along the central channel of the valve cover 11, so that the bottom end face of the packing assembly 16 is completely in contact with the top end face of the pressure self-tightening member 182, so that the subsequent pre-tightening force can be evenly applied to the entire area of ​​the packing assembly 16, thus completing the positioning and assembly of the packing assembly 16.

[0100] S6000, the packing gland 17 is assembled onto the valve cover 11 and the packing assembly 16 is pressed to obtain the valve cover pre-assembled assembly.

[0101] For example, the packing gland 17 is installed on top of the valve cover 11 and locked, so that the packing gland 17 presses against the packing assembly 16, integrating the valve cover 11, the pre-tightening mechanism 18, and the packing assembly 16 into an integrated valve cover pre-assembly assembly, so that the relative positions of the internal components of the valve cover 11 are stable and do not shift, and the pre-assembly of all components on the side of the valve cover 11 is completed.

[0102] S7000, the valve disc 15 is located at the lower end of the valve stem 12, the lower end of the bellows 14 is fixed to the valve disc 15, and the valve stem 12 is assembled into the interior of the valve body 10, so that the valve disc 15 and the hard sealing surface form a sealing fit.

[0103] For example, the valve disc 15 is first assembled at the lower end of the valve stem 12, the lower end of the bellows 14 is fixed to the valve disc 15, and then the assembled valve stem 12 is placed inside the valve body 10. The alignment is adjusted so that the valve disc 15 precisely fits the hard sealing surface of the valve body 10, thereby achieving a basic sealing fit at the opening and closing ends.

[0104] S8000, the valve cover pre-assembly assembly is placed on the valve body 10, the valve stem 12 passes through the valve cover pre-assembly assembly along the central axis of the valve cover 11, and the lower end of the bellows 14 is fixed to the connecting sleeve 13.

[0105] For example, the pre-assembled valve cover assembly is aligned and assembled on the top of the valve body 10, so that the valve stem 12 smoothly passes through the valve cover assembly along the central axis of the valve cover 11 to complete coaxial matching. Finally, the upper end of the bellows 14 is sealed and fixedly connected to the connecting sleeve 13, and the entire set of zero-escape sealing flexible connection structure is opened to complete the overall assembly.

[0106] By adopting the above steps S1000 to S8000, the overall assembly process of the zero-escape hard-seal gate valve 100 is standardized, ensuring the assembly accuracy and fit stability of core components such as the pre-tightening mechanism 18, packing assembly 16, and bellows 14. This ensures that the backup packing is always in a uniform and stable pre-tightened state, improving the problem of long-term idle and deteriorating backup packing. It also enables the bellows 14 to quickly respond and form an effective backup seal when it ruptures, solving the technical problem of media leakage when the bellows 14 ruptures due to the deterioration of the backup packing in related technologies, and improving the sealing reliability and safety of the valve.

[0107] The following description is based on specific embodiments.

[0108] In this embodiment, the experimental objects selected are the DN25 zero-escape hard seal stop valve cover and sealing actuator blank. All experiments are completed on the same automated precision assembly line to ensure that, except for the configuration and assembly control method of the elastic pre-tightening component 181 and the pressure self-tightening component 182, the other processing equipment, assembly environment and raw material specifications are completely consistent.

[0109] Example 1: 1) The annular groove 111 machined inside the valve cover 11 is used as the assembly cavity of the pre-tightening mechanism, and the inclined surface structure integrally machined on the inner side of the annular groove 111 is used as the guide part 1111; through the assembly opening at the lower end of the valve cover 11, the wedge-shaped self-tightening ring (pressure self-tightening component 182) is vertically inserted along the central axis of the annular groove 111, so that the outer peripheral inclined surface of the wedge-shaped self-tightening ring is precisely fitted with the inclined surface of the guide part 1111, and the initial assembly and positioning of the pressure self-tightening component 182 is completed.

[0110] 2) Through the assembly opening at the lower end of the valve cover 11, the cylindrical helical spring (elastic preload 181) is vertically installed into the annular groove 111, so that the upper end face of the cylindrical helical spring and the lower end face of the wedge-shaped self-tightening ring are smoothly abutted, forming a force transmission structure with upper and lower connection.

[0111] 3) The position monitoring unit (laser displacement sensor + visual image acquisition camera) collects the coaxial attitude data of the wedge self-tightening ring relative to the central axis of the annular groove 111 in real time, and the coaxial deviation value is obtained by the data processing module; the load sensing unit (strain gauge pressure sensor) collects the actual preload data of the cylindrical helical spring in real time to ensure accurate data acquisition.

[0112] 4) Based on the collected coaxial deviation value, the assembly actuator performs adaptive coaxial alignment adjustment on the wedge self-tightening ring by relying on the inclined surface guidance of the guide part 1111 until the wedge self-tightening ring and the annular groove 111 are completely coaxial; at the same time, the preload of the cylindrical helical spring is simultaneously calibrated to the preset target value, and the high-precision assembly of the preload mechanism 18 is completed.

[0113] 5) Align the connecting sleeve 13 with the assembly opening at the lower end of the valve cover 11 to complete the alignment. After secure fixing, ensure that the upper end face of the connecting sleeve 13 is in close contact with the lower end face of the cylindrical helical spring to form a limit lock on the pre-tightening mechanism 18 and seal the calibrated pre-tightening state.

[0114] 6) Assemble the packing assembly 16, bellows 14, valve stem 12, and valve disc 15 in sequence. Connect and fix the pre-assembled valve cover assembly to the valve body 10. Seal and fix the upper and lower ends of the bellows 14 to the connecting sleeve 13 and the valve disc 15 respectively to obtain a complete zero-escape hard seal stop valve.

[0115] Example 2: 1) Same as Example 1.

[0116] 2) Through the assembly opening at the lower end of the valve cover 11, the disc spring assembly (elastic preload 181) is vertically installed into the annular groove 111, so that the upper end face of the disc spring assembly and the lower end face of the wedge self-tightening ring are smoothly abutted, forming a force transmission structure with upper and lower connection.

[0117] 3) The position monitoring unit (laser displacement sensor + visual image acquisition camera) collects the coaxial attitude data of the wedge self-tightening ring relative to the central axis of the annular groove 111 in real time, and the coaxial deviation value is obtained by the data processing module; the load sensing unit (strain pressure sensor) collects the actual preload data of the disc spring group in real time to ensure accurate data acquisition.

[0118] 4) Based on the collected coaxial deviation value, the assembly actuator performs adaptive coaxial alignment adjustment on the wedge self-tightening ring by relying on the inclined surface guidance of the guide part 1111 until the wedge self-tightening ring and the annular groove 111 are completely coaxial; at the same time, the preload of the disc spring group is simultaneously calibrated to the preset target value, and the high-precision assembly of the preload mechanism 18 is completed.

[0119] 5) Align the connecting sleeve 13 with the assembly opening at the lower end of the valve cover 11 to complete the alignment. After secure fixing, ensure that the upper end face of the connecting sleeve 13 is in close contact with the lower end face of the disc spring assembly to form a limit lock on the pre-tightening mechanism 18 and seal the calibrated pre-tightening state.

[0120] 6) Assemble the packing assembly 16, bellows 14, valve stem 12, and valve disc 15 in sequence. Connect and fix the pre-assembled valve cover assembly to the valve body 10. Seal and fix the upper and lower ends of the bellows 14 to the connecting sleeve 13 and the valve disc 15 respectively to obtain a complete zero-escape hard seal stop valve.

[0121] Comparative Example 1:1) The annular groove 111 machined inside the valve cover 11 is used as the assembly cavity for the pre-tightening mechanism 18. The inclined structure integrally machined inside the annular groove 111 serves as the guide part 1111. Through the assembly opening at the lower end of the valve cover 11, the cylindrical helical spring (elastic pre-tightening element 181) is vertically installed into the annular groove 111. The wedge-shaped self-tightening ring (pressure self-tightening element 182) is not installed. The packing assembly 16 is directly assembled above the cylindrical helical spring.

[0122] 2) There is no position monitoring unit (laser displacement sensor + visual image acquisition camera) to detect coaxial posture, and no adaptive coaxial alignment adjustment of assembly actuator. The assembly of packing assembly 16, bellows 14, valve stem 12 and valve disc 15 is completed manually in a conventional manner.

[0123] 3) Align the connecting sleeve 13 with the assembly opening at the lower end of the valve cover 11 to complete the alignment and fixation, so that the upper end face of the connecting sleeve 13 is in close contact with the lower end face of the cylindrical helical spring; the remaining assembly process and parameters are completely consistent with those in Example 1, and a complete zero-escape hard seal shut-off valve is obtained.

[0124] Comparative Example 2:1) The annular groove 111 machined inside the valve cover 11 is used as the assembly cavity for the pre-tightening mechanism 18. The inclined surface structure integrally machined on the inner side of the annular groove 111 serves as the guide part 1111. Through the assembly opening at the lower end of the valve cover 11, the wedge-shaped self-tightening ring (pressure self-tightening element 182) is vertically installed along the central axis of the annular groove 111, so that the outer peripheral inclined surface of the wedge-shaped self-tightening ring fits against the inclined surface of the guide part 1111. The cylindrical helical spring (elastic pre-tightening element 181) is not installed, and the packing assembly 16 is directly assembled above the wedge-shaped self-tightening ring.

[0125] 2) The no-load sensing unit (strain gauge pressure sensor) detects the preload. There is no preload calibration operation, and the assembly of the remaining components is completed manually in a routine manner.

[0126] 3) Align the connecting sleeve 13 with the assembly opening at the lower end of the valve cover 11 to complete the alignment and fixation (there is no elastic pre-tightening part to abut, it only serves to seal the assembly opening); the rest of the assembly process and parameters are completely consistent with those in Example 1, and a complete zero-escape hard seal shut-off valve is obtained.

[0127] Performance Tests and Results 1. Testing Method 1) Sealing fit coaxiality: The coaxiality deviation between the pressure self-tightening component 182 / packing assembly 16 and the center axis of the valve cover 11 is detected by a coaxiality tester. The lower the deviation value, the higher the fit accuracy.

[0128] 2) Preload uniformity: The uniformity of preload distribution on the end face of the packing assembly 16 is tested using a pressure distribution tester. The higher the uniformity value, the better the preload effect.

[0129] 3) Packing service life: Simulate the actual opening and closing conditions of the valve and record the number of opening and closing times before the packing assembly 16 deteriorates and fails. The more times it is opened and closed, the longer its service life.

[0130] 4) Leakage rate: The leakage rate of the valve medium seal is tested according to GB / T 13927 standard. The lower the leakage rate, the better the sealing performance.

[0131] 5) Assembly accuracy pass rate: Statistically calculate the proportion of products that meet the standards for pre-tightening mechanism 18 and sealing component assembly in batch assembly. The higher the pass rate, the better the assembly stability.

[0132] All tests were conducted in triplicate, and were performed in an industrial testing environment at normal temperature and pressure. The results were taken as mean ± standard deviation.

[0133] 2. Test Results Depend on Figure 6 The performance test results of Examples 1-2 and Comparative Examples 1-2 show significant differences, as detailed below: 1) Coaxiality of sealing fit: The coaxiality deviation of Examples 1 and 2 is ≤0.02mm, the deviation of Comparative Example 1 is ≥0.15mm, and the deviation of Comparative Example 2 is ≥0.12mm.

[0134] 2) Preload uniformity: The preload uniformity of Examples 1 and 2 is ≥98%, while that of Comparative Example 1 is only 72% and that of Comparative Example 2 is only 75%.

[0135] 3) Packing service life: The packing opening and closing service life of Examples 1 and 2 is ≥150,000 times, while that of Comparative Example 1 is only 60,000 times, Comparative Example 2 is only 70,000 times, and Comparative Example 3 is only 40,000 times.

[0136] 4) Leakage rate: Leakage rate of Examples 1-2 ≤ 1×10 -6 Pa·m³ / s, achieving the zero-escape sealing standard; Comparative Example 1 showed a leakage rate of 5×10⁻⁶. -4 Pa·m³ / s, Comparative Example 2 reaches 4×10 -4 Pa·m³ / s.

[0137] 5) Assembly accuracy pass rate: The batch assembly pass rate of Examples 1 and 2 is ≥99.5%, Comparative Example 1 is 78%, and Comparative Example 2 is 82%.

[0138] in conclusion Embodiments 1 and 2 of this application employ a technical solution combining an annular groove 111, a guide part 1111, an elastic pre-tightening element 181 and a pressure self-tightening element 182, adaptive assembly control, and a connecting sleeve 13 for limiting and locking. This solution addresses the core defects of traditional structures in terms of structural feasibility, component fit, and assembly accuracy. 1. The elastic pre-tightening element 181 and the pressure self-tightening element 182 work together, relying on the inclined guiding effect of the guide part 1111, to ensure stable output of pre-tightening force and achieve high-precision coaxial positioning of the sealing assembly; 2. Adaptive coaxial alignment and preload calibration, combined with the limiting lock of the connecting sleeve 13, reduce assembly deviations, ensure uniform force on the packing assembly 16, delay packing deterioration and failure from the source, and at the same time ensure the valve's zero-escape sealing performance.

[0139] Comparative Example 1 only has an elastic pre-tightening element 181, without the positioning function of the pressure self-tightening element 182 and the guide part 1111, resulting in poor coaxiality and uneven force on the packing; Comparative Example 2 only has a pressure self-tightening element 182, without the elastic pre-tightening element 181 to provide stable pre-tightening force, the pre-tightening force is missing and the stability is insufficient, and the normal sealing effect cannot be guaranteed.

[0140] In summary, the structural design and assembly method of this application effectively solve the technical problems of traditional zero-escape hard-seal gate valves, such as single pre-tightening components, low assembly coaxiality, uneven pre-tightening force leading to packing deterioration and sealing leakage. It has significant technical advantages in sealing accuracy, packing life, and assembly stability, and meets the industrial application requirements of zero-escape hard-seal gate valves.

[0141] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A zero-escape hard-seal shut-off valve, characterized in that, include: The valve body has a hard sealing surface welded to the inner side of the flow channel; A valve cover is provided on the valve body. An annular groove is provided inside the valve cover, and a guide part is provided in the annular groove. An assembly opening is provided at the lower end of the valve cover. The valve stem passes through the valve cover and can move up and down along the central axis of the valve cover; The connecting sleeve is fixed to the assembly opening; A bellows, the upper end of which is fixed to the connecting sleeve; A valve disc is located at the lower end of the valve stem, and the valve disc is sealed to the hard sealing surface. The lower end of the bellows is fixed to the valve disc. A packing assembly is disposed inside the valve cover, and the packing assembly is located above the bellows; the guide portion is disposed between the upper end of the bellows and the lower end of the packing assembly. A packing gland is provided on the valve cover, and the packing gland presses against the packing assembly; A pre-tightening mechanism, comprising an elastic pre-tightening element and a pressure self-tightening element; the lower end of the elastic pre-tightening element abuts against the upper end of the connecting sleeve, the upper end of the elastic pre-tightening element abuts against the lower end of the pressure self-tightening element, and the upper end of the pressure self-tightening element abuts against the lower end of the packing assembly; the pressure self-tightening element is connected to the guide portion.

2. The zero-escape hard-seal shut-off valve as described in claim 1, characterized in that, The guide portion is a beveled fit structure, which includes a first bevel on the outer circumferential surface of the pressure self-tightening member and a second bevel on the inner circumferential surface of the annular groove that fits with the first bevel.

3. The zero-escape hard-seal shut-off valve as described in claim 2, characterized in that, The pressure self-tightening component is a wedge-shaped self-tightening ring, and the first inclined surface is an integrally formed inclined surface on the outer circumferential surface of the wedge-shaped self-tightening ring.

4. The zero-escape hard-seal shut-off valve as described in claim 1, characterized in that, The elastic preload is a cylindrical helical spring, a disc spring assembly, or a wave spring, and the elastic preload is sleeved on the outside of the valve stem.

5. The zero-escape hard-seal shut-off valve as described in claim 1, characterized in that, The packing assembly includes a lower packing pad, a packing body, and a packing sleeve arranged sequentially from bottom to top; the upper end of the pressure self-tightening member abuts against the lower packing pad, and the packing gland abuts against the packing sleeve and presses the packing body.

6. A method for assembling a zero-escape hard-seal shut-off valve, characterized in that, The method for assembling the zero-escape hard-seal shut-off valve according to any one of claims 1 to 5 includes: The pressure self-tightening member is assembled into the annular groove through the assembly opening, and the pressure self-tightening member cooperates with the guide portion. The elastic preload is assembled into the annular groove through the assembly opening, with the upper end of the elastic preload abutting against the lower end of the pressure self-tightening member. Based on the guide portion, the control assembly actuator performs adaptive coaxial alignment between the pressure self-tightening member and the annular groove, and calibrates the preload of the elastic preload member; The connecting sleeve is fixedly installed at the assembly opening, and the lower end of the elastic preload abuts against the upper end of the connecting sleeve. The packing assembly is assembled into the interior of the valve cover, with the lower end of the packing assembly abutting against the upper end of the pressure self-tightening member; The packing gland is assembled onto the valve cover and the packing assembly is pressed to obtain a pre-assembled valve cover assembly. The valve disc is placed at the lower end of the valve stem, the lower end of the bellows is fixed to the valve disc, and the valve stem is then assembled into the interior of the valve body. The valve disc and the hard sealing surface form a sealing fit. The valve cover pre-assembly assembly is placed on the valve body, the valve stem passes through the valve cover pre-assembly assembly along the central axis of the valve cover, and the upper end of the bellows is fixed to the connecting sleeve.

7. The assembly method of the zero-escape hard-seal shut-off valve as described in claim 6, characterized in that, The control assembly actuator performs adaptive coaxial alignment of the pressure self-tightening component and the annular groove, including: The position monitoring unit collects the coaxial attitude data of the pressure self-tightening component relative to the annular groove in real time. The coaxial deviation value of the pressure self-tightening component relative to the annular groove is determined based on the coaxial attitude data; The assembly actuator is controlled to adjust the assembly posture of the pressure self-tightening component according to the coaxial deviation value.

8. The assembly method of the zero-escape hard-seal shut-off valve as described in claim 7, characterized in that, Determining the coaxial deviation value of the pressure self-tightening component relative to the annular groove based on the coaxial attitude data includes: Based on the central axis of the annular groove, a reference coordinate system for coaxial alignment is established, and the standard assembly posture parameters under the reference coordinate system are calibrated. Based on the assembly deformation characteristics of the elastic preload, the coaxial attitude data is compensated and corrected to obtain the corrected coaxial attitude data. The corrected coaxial posture data is compared and calculated with the standard assembly posture parameters to obtain the coaxial deviation value of the pressure self-tightening component relative to the annular groove.

9. The assembly method of the zero-escape hard-seal shut-off valve as described in claim 8, characterized in that, The step of compensating and correcting the coaxial attitude data based on the assembly deformation characteristics of the elastic preload to obtain corrected coaxial attitude data includes: Based on the assembly deformation characteristics of the elastic preload, the assembly deformation parameters corresponding to the elastic preload are determined. The compensation coefficient corresponding to the coaxial attitude data is determined based on the assembly deformation parameters. The coaxial attitude data is corrected by calculating the compensation coefficient to obtain the corrected coaxial attitude data.

10. The assembly method of the zero-escape hard-seal shut-off valve as described in claim 6, characterized in that, The calibration of the preload of the elastic preload includes: The actual preload data of the elastic preload member is collected in real time by the load sensing unit. The actual preload data is compared with the preset target load data; The assembly actuator is controlled to adjust the pressure applied to the elastic preload based on the comparison results.

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