A packing gland seal structure with reverse flange gland

Abstract

The utility model discloses a packing gland sealing structure with reverse flange gland, and the sealing structure comprises a short section, a packing groove, a reverse flange type packing gland, a fastening assembly and a baffle ring. Through the reverse flange type packing gland design, combining with self-tight spring or manual nut pre-tightening, the problem of insufficient rigidity of the traditional packing gland and complicated dismounting is solved. It is especially suitable for the sealing scene of the cylinder and the pipe orifice which need bidirectional displacement compensation, high pressure and high temperature and frequent maintenance.

Description

Technical Field

[0001] This utility model relates to the field of pipeline and container sealing technology, and in particular to a stuffing box sealing structure with a reverse flange gland. Background Technology

[0002] Traditional cylindrical flanges or pipe joint seals mostly use end face gaskets, which have the following drawbacks:

[0003] 1. Simple gland structure: Conventional flat glands are prone to deformation under high pressure, resulting in uneven packing compaction;

[0004] 2. Inconvenient disassembly and assembly: Replacing the gasket requires completely separating the flange, which is cumbersome.

[0005] 3. Poor resistance to eccentric loads: Axial displacement or vibration can easily cause seal failure.

[0006] While various stuffing box seal structures exist in existing technologies, they all have some limitations in application. For example, CN221075645U uses single-sided spring compensation and cannot adapt to bidirectional displacement; CN215410180U's dual-chamber structure is complex and unsuitable for compact spaces; CN206626182U's gland is an integral type and cannot dynamically adjust the sealing surface pressure; and CN202803232U's self-tightening buffer is limited to axial compensation and lacks sufficient radial sealing. Although stuffing box seals are used for rotary shaft sealing and also in heat exchangers or valves, their application to cylinder and nozzle structures is not optimized. Therefore, there is an urgent need for a sealing solution that is easy to maintain and can withstand axial displacement. Utility Model Content

[0007] This invention addresses the problems of insufficient gland rigidity, cumbersome disassembly and assembly, and poor displacement resistance in existing stuffing box sealing structures by providing an innovative stuffing box sealing structure with a reverse flange gland. It includes: a short section 1, a stuffing groove disposed on the outside of the short section 1, a reverse flange stuffing gland 5, a fastening assembly, and a retaining ring 2 fixed to one side of the short section 1. The flange end of the reverse flange stuffing gland 5 extends outward from the short section 1 and is connected to the short section 1 via the fastening assembly.

[0008] Preferably, the fastening assembly includes a bolt 6 and a self-tightening spring 7, the self-tightening spring being sleeved on the bolt 6, and the flange end face of the reverse flange type packing gland 5 having an annular groove, the bolt 6 being disposed in the annular groove.

[0009] Preferably, the fastening assembly includes a welded stud 8 and a nut 9.

[0010] Preferably, the retaining ring 2 and the short section 1 are separate welded structures.

[0011] Preferably, the reverse flange type packing gland 5 has a through hole in the center.

[0012] Preferably, the flange thickness of the reverse flange type packing gland 5 is 0.25 to 0.8 times the thickness of the gland body.

[0013] Preferably, the inclination angle of the pressing end of the gland flange of the reverse flange type packing gland 5 is 5° to 25°.

[0014] Preferably, a soft metal ring 3 is provided between the retaining ring 2 and the sealing packing 4.

[0015] Preferably, the diameter of the soft metal ring 3 is 3 to 10 mm.

[0016] Preferably, the diameter of the through hole is 60% to 110% of the inner diameter of the short section 1.

[0017] Compared with existing technologies, this utility model has the following technical effects: the reverse flange increases the rigidity of the gland, avoiding high-pressure deformation, and also facilitates quick disassembly and assembly. Through the rigidity enhancement of the reverse flange gland, the dual-mode compensation mechanism, and the quick-disassembly design, the three major pain points of traditional sealing glands—deformation, compensation lag, and cumbersome maintenance—are thoroughly solved, significantly improving the "zero-leakage" lifespan under high pressure, high temperature, and frequent disassembly conditions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the automatic preload compensation stuffing box seal of this utility model;

[0019] Figure 2 This is a schematic diagram of the structure of the manually compensated preload packing gland seal of this utility model.

[0020] Figure 3 This is one type of reverse flange type packing gland of this utility model.

[0021] In the diagram, 1 is a short section, 2 is a retaining ring, 3 is a soft metal ring, 4 is a sealing packing, 5 is a reverse flange packing gland, 6 is a bolt, 7 is a self-tightening spring, 8 is a stud, and 9 is a nut. Detailed Implementation

[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0023] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate to understand the embodiments of the utility model described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a product or device comprising a series of units is not necessarily limited to those explicitly listed, but may include other units not explicitly listed or inherent to such product or device.

[0024] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this invention and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0025] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this utility model according to the specific circumstances.

[0026] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this utility model based on the specific circumstances.

[0027] It should be noted that, where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0028] Example 1

[0029] In existing technologies, the pipeline and container sealing field has long faced challenges such as gland deformation under high-pressure conditions, cumbersome maintenance operations, and insufficient axial displacement compensation. Traditional end-face gasket sealing structures use a flat gland design, which is prone to uneven deformation in high-pressure environments, leading to seal failure. Replacing the packing requires complete disassembly of the flange connection, severely impacting maintenance efficiency.

[0030] To address these issues, researchers modified the stress distribution of the gland by extending the flange end outwards to form a reverse support structure, significantly improving overall rigidity. Simultaneously, a split-type connection design was adopted, creating an adjustable axial constraint mechanism between the gland and the short section. This ensures ease of initial assembly and provides quick disassembly and assembly for subsequent maintenance.

[0031] Therefore, this application proposes a stuffing box sealing structure with a reverse flange gland 5, including a short section 1, a stuffing groove disposed on the outside of the short section 1, a reverse flange stuffing gland 5, a fastening assembly, and a retaining ring 2 fixed to one side of the short section 1. The flange end of the reverse flange stuffing gland 5 extends outward from the short section 1 and is connected to the short section 1 by the fastening assembly.

[0032] In this embodiment, the flange end of the reverse flange type packing gland 5 extends outward from the short section 1, specifically using an annular flange structure. This extension forms a mechanical support point, changing the cantilever stress state of the traditional gland to a simply supported beam mode. In this embodiment, the fastening assembly uses a combination of bolts 6 and self-tightening springs 7, achieving automatic compensation through spring preload. In another embodiment, the fastening assembly uses a combination of welded studs 8 and nuts 9, providing manual compensation through thread adjustment. The retaining ring 2 is welded separately to the short section 1, avoiding stress deformation caused by overall machining and reducing machining accuracy requirements.

[0033] Specifically, the packing groove on the outside of the short section 1 is used to accommodate the sealing packing 4, and the reverse flange type packing gland 5 is rigidly connected to the short section 1 through its outwardly extending flange end. During assembly, the fastening assembly applies axial pressure, causing the gland and retaining ring 2 to jointly compress the packing 4, forming a bidirectional sealing constraint. When the system experiences axial displacement, the reverse flange structure maintains the flatness of the gland through enhanced bending stiffness, preventing seal failure due to deformation. During maintenance, the gland can be removed simply by loosening the fastening assembly without damaging the overall flange connection.

[0034] Compared to existing technologies, traditional flat-faced glands are prone to central area depression and deformation under high pressure, resulting in uneven distribution of packing clamping force. The reverse flange design in this solution shifts the stress point of the gland outward, significantly reducing bending stress. Existing technologies require disassembling the entire flange bolts to replace the packing, while the fastening components of this structure are independently connected to the main flange, enabling rapid localized maintenance.

[0035] Through the above technical solutions, this application effectively improves the rigidity of the gland structure and ensures uniform compression of the sealing surface under high pressure conditions; simplifies the disassembly and assembly process and shortens maintenance time through the split fastening mechanism; and utilizes the bidirectional constraint formed by the reverse flange and the retaining ring 2 to adapt to the displacement compensation requirements caused by the axial expansion and contraction of the pipeline and maintain long-term sealing reliability.

[0036] like Figure 1 As shown, this application further proposes a fastening assembly including a bolt 6 and a self-tightening spring 7, the self-tightening spring 7 being sleeved on the bolt 6, and the flange end face of the reverse flange type packing gland 5 being provided with an annular groove, the bolt 6 being disposed in the annular groove.

[0037] Bolt 6 refers to the fastener used to connect the reverse flange-type packing gland 5 and the short section 1. Specifically, it can be a hexagonal head bolt with a threaded shank. Bolt 6 passes through the annular groove on the end face of the gland flange and mates with the threaded hole on the outer side of the short section 1, forming an adjustable fastening connection. Self-tightening spring 7 refers to the elastic element sleeved on the shank of bolt 6. Specifically, it can be a helical compression spring. The two ends of the spring abut against the head of bolt 6 and the end face of the gland flange, respectively, storing elastic potential energy in a pre-tightened state. The annular groove refers to the groove structure distributed circumferentially on the end face of the gland flange. Specifically, it can be formed by machining annular grooves. The inner diameter of the groove is clearance-fitted with the shank of bolt 6, used to limit the radial displacement of bolt 6 and maintain the compression direction of the spring.

[0038] Specifically, bolt 6 passes through the annular groove on the end face of the gland flange and connects to the threaded hole on the outer side of the short section 1. Tightening bolt 6 compresses the self-tightening spring 7. When the sealing packing 4 wears due to long-term use, the self-tightening spring 7 releases its stored elastic potential energy, pushing the gland to move axially along bolt 6 to compensate for the volume change of the packing 4 and maintain the continuous pressure on the sealing surface. The annular groove forms a circumferential constraint on the bolt 6, preventing the spring from shifting laterally during compression and ensuring uniform force on the gland. During disassembly and maintenance, simply loosening bolt 6 allows the gland to be removed along the groove guide path without completely separating the connecting parts.

[0039] Compared to existing technologies, traditional packing glands, which use rigid bolts for direct fastening, cannot adapt to the dynamic wear of the packing and are prone to pressure attenuation. This solution utilizes the elastic energy storage characteristics of springs to achieve automatic pressure compensation, combined with the positioning function of the groove for bolt 6. This solves the problem of gland deformation under high-pressure conditions and simplifies maintenance procedures. Compared to a single welded fixing structure, the detachable bolt 6 connection significantly improves maintenance efficiency.

[0040] Through the above technical solution, this application effectively solves the leakage problem caused by packing wear in high-pressure sealing systems and realizes the dynamic self-adjustment function of sealing pressure. The matching design of the annular groove and bolt 6 avoids local stress concentration caused by fastener misalignment, ensuring uniform force distribution on the gland. The elastic compensation mechanism of the self-tightening spring 7 extends the effective service life of the sealing system, while simplifying maintenance procedures and reducing equipment downtime.

[0041] This application further proposes that the retaining ring 2 and the short section 1 are separate welded structures.

[0042] The split-welded structure refers to the retaining ring 2 and the short section 1 being manufactured as independent components and then welded together. This structure eliminates residual stress generated during overall processing through split manufacturing and avoids flatness deviations in the retaining ring 2 caused by uneven material shrinkage.

[0043] Specifically, when the sealing surface wears down due to long-term use, the retaining ring 2 can be removed and replaced simply by cutting the weld, without having to replace the entire main structure of the short section 1.

[0044] In existing technologies, the entire short section assembly must be replaced during maintenance, while this solution achieves partial replaceability through a split design, significantly reducing maintenance costs.

[0045] Through the above technical solution, this application effectively solves the problem of deformation of the retaining ring 2 caused by differences in structural rigidity during the overall processing. Separate manufacturing improves the processing accuracy of the retaining ring 2 and is not constrained by the dimensions of the short section 1. The welding connection method ensures structural reliability while achieving optimized combination and use of dissimilar materials.

[0046] This application further proposes that the reverse flange type packing gland 5 has a through hole in the center.

[0047] The through hole refers to a channel structure that penetrates the central axis of the gland and communicates with the inner cavity of the short section 1. Specifically, the through hole can be formed on the gland body by mechanical processing. This channel structure allows testing tools or unblocking devices to be directly inserted into the sealing cavity without disassembling the gland.

[0048] Specifically, the through-hole structure allows maintenance personnel to insert a detection probe through the hole to monitor the sealing status while the system is running continuously, or to use a cleaning tool to remove foreign objects from the sealing cavity.

[0049] Compared to existing technologies, traditional sealing structures employ a closed gland design, requiring complete disassembly of the sealing components and system shutdown for inspection or maintenance. This solution, by incorporating a specific ratio of through-holes, enables online maintenance while maintaining the integrity of the sealing function, effectively resolving the conflict between maintenance operations and continuous system operation.

[0050] Through the above technical solution, this application realizes the online maintenance function of the sealing structure, enabling the detection probe or unblocking tool to directly intervene in the sealing cavity without interrupting system operation, significantly improving the convenience of maintenance operations. This design effectively avoids production interruptions caused by downtime maintenance, while reducing the risk of secondary damage during the disassembly and assembly of the sealing structure.

[0051] This application further proposes that the flange thickness of the reverse flange type packing gland 5 is 0.25 to 0.8 times the thickness of the gland body.

[0052] The flange thickness refers to the axial dimension of the outwardly extending annular support structure in the reverse flange-type packing gland 5. It can be formed by machining or casting, and its thickness ratio is determined through structural mechanics calculations. The gland body thickness refers to the radial dimension of the main body of the gland, specifically designed by matching material strength with load distribution. This parameter range ensures that the flange provides effective support while avoiding localized stress concentration.

[0053] Specifically, the flange and body of the reverse flange-type packing gland 5 adopt a stepped transition structure, with the ratio of flange thickness to body thickness controlled within the range of 0.25 to 0.8. When the flange thickness is below the lower limit, the bending stiffness of the flange end face is insufficient to balance the radial load under high pressure conditions; when it exceeds the upper limit, stress concentration during processing easily occurs in the transition area. Finite element simulation verification shows that this ratio range makes the stress distribution at the flange root tend to be uniform when the gland is subjected to combined axial compression and radial bending loads, while maintaining the overall structural compactness.

[0054] Compared to existing technologies, traditional flat-faced glands use flanges of uniform thickness, which are prone to plastic deformation at the flange root under high pressure. This solution optimizes the ratio of flange to body thickness, achieving an optimal balance between the gland's support stiffness and material utilization. Existing technologies commonly employ overall thickening designs to enhance rigidity, leading to increased gland weight and manufacturing costs. This solution, however, achieves lightweighting with the same rigidity through localized reinforcement design.

[0055] Through the above technical solution, this application effectively solves the contradiction between gland deformation and material redundancy in high-pressure sealing scenarios. While ensuring uniform pressure distribution on the sealing surface, it reduces the manufacturing cost of the gland and extends the service life of the sealing structure under alternating loads.

[0056] like Figure 2 As shown, this application further proposes that the inclination angle of the clamping end of the gland flange of the reverse flange type packing gland 5 is 5° to 25°.

[0057] The inclination angle of the gland flange clamping end refers to the angle formed between the end face of the gland flange and the axial direction of the gland. Specifically, it can be achieved by machining a contact surface with an inclined surface. This inclination angle range allows the gland to convert part of the axial force into a radial component when subjected to axial tightening force, thereby optimizing the circumferential clamping effect of the sealing packing 4.

[0058] The structural strength of the gland flange clamping end is achieved through the matching relationship between the tilt angle and the flange thickness. Specifically, the optimal ratio of the tilt angle to the flange thickness can be determined using finite element stress analysis. This design ensures that the gland, when subjected to high pressure loads, can avoid stress concentration at the flange root while maintaining sufficient bending stiffness.

[0059] Specifically, when the clamping end of the gland flange forms an inclined contact surface of 5° to 25°, the axial preload applied by bolt 6 is decomposed into an axial clamping component and a radial expansion component. When the inclination angle is close to 5°, the proportion of the radial component increases, which is beneficial for compensating for the wear clearance of the sealing packing 4; when the inclination angle is close to 25°, the proportion of the axial component increases, which can reduce the loss of the preload of bolt 6. This angle range, through the mechanical decomposition effect of the inclined plane, makes the contact pressure of the sealing packing 4 form a continuous and uniform distribution zone in the circumference, eliminating the local high pressure zone in the edge area of ​​the traditional flat end face gland.

[0060] Compared with existing technologies, traditional packing glands use a right-angled end face structure, which easily leads to edge stress concentration during tightening, causing uneven circumferential compression of the sealing packing 4. This solution uses the force component of the inclined contact surface to make the compression deformation of the sealing packing 4 more uniform along the circumferential direction, fundamentally improving the pressure distribution at the sealing interface.

[0061] Through the above technical solution, this application effectively solves the problem of unbalanced pressure distribution on the sealing surface caused by insufficient rigidity of the gland, enabling the sealing packing 4 to obtain stable contact stress under high temperature and high pressure conditions. The inclined clamping end structure enhances the gland's resistance to bending deformation, while adapting to the sealing compensation requirements of different wear levels, significantly improving the reliability of the sealing interface.

[0062] This application further proposes to provide a soft metal ring 3 between the retaining ring 2 and the sealing packing 4.

[0063] The soft metal ring 3 refers to a ring-shaped component made of a metal material with a higher plastic deformation capacity than the retaining ring 2. Specifically, it can be made of aluminum-based alloys, copper-based alloys, or silver-based alloys, etc., utilizing its high ductility to generate uniform plastic flow under pressure. The pressure adaptive leveling refers to the compensation of micro-unevenness of the contact surface by the elastic deformation of the soft metal ring 3, so that the ring body produces controllable plastic deformation under axial pressure.

[0064] Specifically, when the retaining ring 2 applies axial clamping force to the sealing packing 4, the soft metal ring 3 undergoes elastoplastic deformation at the contact interface. This deformation process fills the microscopic gap between the mounting surface of the retaining ring 2 and the contact surface of the packing 4, eliminating local stress concentration caused by machining errors or assembly misalignment. Under high-temperature conditions, the coefficient of thermal expansion of the soft metal ring 3 is between that of the retaining ring 2 and the sealing packing 4, effectively buffering the thermal expansion differences between different materials. When the system undergoes multiple disassembly and maintenance, the soft metal ring 3 maintains the fit of the contact surface through repeated plastic deformation, avoiding damage to the sealing surface caused by repeated tightening.

[0065] Compared with existing technologies, this solution uses a soft metal buffer layer to distribute the contact pressure evenly in the circumferential direction while maintaining sufficient axial stiffness to transmit the preload.

[0066] Through the above technical solution, this application effectively solves the problem of local leakage caused by uneven pressure distribution at the sealing interface, significantly improves the reliability of the sealing system under high temperature thermal cycling conditions, and at the same time reduces the machining accuracy requirements of the contact surfaces of the retaining ring 2 and the packing 4, and extends the maintenance cycle of the sealing assembly.

[0067] This application further proposes a soft metal ring 3 with a diameter of 3 to 10 mm.

[0068] The selection of this diameter range is based on the need to balance the pressure transmission and deformation compensation at the sealing interface, ensuring both structural strength and elastic deformation capability.

[0069] Specifically, the diameter range of the soft metal ring 3 functions by matching the compression deformation characteristics of the sealing packing 4. When the gland applies axial clamping force, the soft metal ring 3 undergoes controllable radial expansion deformation under pressure, thereby eliminating the microscopic gaps at the contact surface between the sealing packing 4 layer and the retaining ring 2. If the diameter is too small, the soft metal ring 3 will have excessive rigidity and will not be able to effectively absorb the local deformation differences of the sealing packing 4; if the diameter is too large, the soft metal ring 3 will deform excessively, weakening the efficiency of transmitting the clamping force. By limiting the diameter to the range of 3 to 10 mm, the soft metal ring 3 can both uniformly distribute the clamping force to the entire cross-section of the sealing packing 4 and compensate for interface unevenness caused by assembly errors or thermal expansion through elastic deformation.

[0070] Compared with the prior art, the diameter range determined in this application effectively balances structural strength and deformation capacity, and solves the contradiction between stress concentration and compensation failure at the sealing interface in the prior art.

[0071] Through the above technical solution, this application achieves a uniform distribution of compressive stress on the sealing packing 4, eliminating the risk of cracking or leakage at the sealing interface caused by local stress concentration. The elastic deformation capability of the soft metal ring 3 within a specific diameter range can automatically compensate for the wear of the sealing packing 4, maintain stable contact pressure, and thus extend the effective service life of the sealing structure under high temperature and high pressure conditions.

[0072] This application further proposes that the diameter of the central through hole of the reverse flange type packing gland 5 is 60% to 110% of the inner diameter of the short section 1.

[0073] This scale range was determined through computational fluid dynamics simulations to ensure the load-bearing capacity of the gland structure while providing the necessary space for the tool to pass through.

[0074] Specifically, when the diameter of the through hole reaches 60% of the inner diameter of section 1, it can meet the insertion requirements of conventional detection probes; when the diameter is expanded to 110%, it can adapt to the operational requirements of large-scale unblocking tools. This hole diameter range balances structural strength and functional requirements, avoiding the decrease in gland rigidity caused by excessively large openings, and eliminating the technical obstacle of having to stop and disassemble the traditional sealing structure for maintenance.

[0075] Compared with existing technologies, this solution, by setting a specific ratio of through-hole structures, enables online maintenance operations while maintaining the integrity of the sealing function, effectively resolving the contradiction between maintenance work and continuous system operation.

[0076] Through the above technical solution, this application solves the contradiction between the elastic leveling ability and structural strength of the soft metal ring 3 in high-pressure sealing scenarios. It avoids the risk of crushing failure caused by the ring being too thin, and also prevents the problem of insufficient deformation space caused by the ring being too thick. This ensures that the sealing filler 4 maintains a uniform pressure distribution throughout the entire working cycle and effectively improves the dynamic adaptability of the sealing interface.

[0077] Example 2

[0078] like Figure 2 As shown, another embodiment of this application provides manual compensation for the fastening assembly through thread adjustment. Compared with the fastening assembly consisting of bolt 6 and self-tightening spring 7 provided in Embodiment 1, the fastening assembly of Embodiment 2 includes welded studs 8 and nuts 9. This structure relies entirely on mechanical fastening to achieve preload adjustment, without relying on elastic elements, resulting in lower costs. It is particularly suitable for working environments where high-temperature thermal expansion or chemical corrosion can cause elastic elements to fail.

[0079] The welded stud 8 is a connector that fixes one end of the stud to the outer surface of the short section 1 by welding. The nut 9 is a fastener that threads with the welded stud 8. This assembly controls the degree of compression of the gland onto the sealing packing 4 by changing its axial position on the stud 8 by tightening the nut 9.

[0080] Specifically, the welded stud 8 is vertically fixed to the outer side of the end face of the short section 1, with its threaded end passing through the mounting hole of the reverse flange-type packing gland 5. After the nut 9 is screwed into the stud 8, torque is applied using a wrench to make the end face of the nut 9 abut against the surface of the gland. When the sealing packing 4 wears due to long-term use, the operator can push the gland axially along the stud 8 by tightening the nut 9 to compensate for the gap caused by the volume loss of the packing 4. This structure relies entirely on mechanical fastening to achieve preload adjustment, without relying on elastic elements.

[0081] Compared with existing technologies, the adjustment process of nut 9 does not require disassembling the entire fastening assembly. Preload restoration can be completed with only one-sided operation, which significantly improves maintenance efficiency.

[0082] Through the above technical solution, this application solves the problems of cumbersome disassembly and assembly of fastening components and inability to adapt to manual adjustment of preload requirements in traditional stuffing box sealing structures. The permanent fixing characteristics of the welded stud 8 ensure the long-term stability of the connection structure, and the manual adjustment function of the nut 9 allows the sealing clamping force to be corrected in real time according to changes in working conditions, which is especially suitable for sealing scenarios in chemical pipelines that require frequent maintenance or contain highly corrosive media.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Those skilled in the art should understand that modifications can be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; these modifications or substitutions do not cause the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A stuffing box sealing structure with a reverse flange gland, characterized in that, include: The short section (1), a packing groove disposed on the outside of the short section (1), a reverse flange packing gland (5), a fastening assembly, and a retaining ring (2) fixed to one side of the short section (1), wherein the flange end of the reverse flange packing gland (5) extends outward toward the short section (1) and is connected to the short section (1) through the fastening assembly.

2. The stuffing box sealing structure according to claim 1, characterized in that: The fastening assembly includes a bolt (6) and a self-tightening spring (7). The self-tightening spring is sleeved on the bolt (6). The flange end face of the reverse flange type packing gland (5) is provided with an annular groove, and the bolt (6) is disposed in the annular groove.

3. The stuffing box sealing structure according to claim 1, characterized in that: The fastening assembly includes a welded stud (8) and a nut (9).

4. The stuffing box sealing structure according to any one of claims 1-3, characterized in that: The retaining ring (2) and the short section (1) are separate welded structures.

5. The stuffing box sealing structure according to any one of claims 1-3, characterized in that: The reverse flange type packing gland (5) has a through hole in the center.

6. The stuffing box sealing structure according to any one of claims 1-3, characterized in that: The flange thickness of the reverse flange type packing gland (5) is 0.25 to 0.8 times the thickness of the gland body.

7. The stuffing box sealing structure according to any one of claims 1-3, characterized in that: The inclination angle of the pressing end of the flange of the reverse flange type packing gland (5) is 5° to 25°.

8. The stuffing box sealing structure according to any one of claims 1-3, characterized in that: A soft metal ring (3) is provided between the retaining ring (2) and the sealing packing (4).

9. The stuffing box sealing structure according to claim 8, characterized in that: The diameter of the soft metal ring (3) is 3 to 10 mm.

10. The stuffing box sealing structure according to claim 5, characterized in that: The diameter of the through hole is 60% to 110% of the inner diameter of the short section (1).

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