Flexible sealing device for boilers

Abstract

The utility model relates to a kind of flexible sealing device for boiler, belong to boiler sealing technical field, to solve the problem of traditional sealing fatigue cracking and leakage caused by boiler pipeline thermal displacement. The device adopts annular sealing body made of flexible high-temperature resistant fiber fabric, its ring wall constitutes bellows structure, the structure is constituted by annular wave trough and annular wave crest connected alternately, wherein the valley bottom wall thickness of annular wave trough is greater than the peak top wall thickness of annular wave crest, and the curved surface radius of annular wave trough is greater than the curved surface radius of annular wave crest. The device has annular mounting edge formed by radially outward flanging at both ends, and the root of mounting edge is connected with adjacent annular wave crest or annular wave trough through transition area with wave shape. The design enhances the flexibility and fatigue resistance of structure through optimized wall thickness distribution and curvature relationship, and uses wave-shaped transition area to relieve root stress concentration, mainly used for compensating thermal displacement and maintaining long-term effective sealing in boiler pipeline system.

Description

Technical Field

[0001] This utility model belongs to the field of boiler sealing technology, specifically relating to a flexible sealing device for boilers. Background Technology

[0002] During operation, boiler equipment undergoes significant thermal expansion and contraction due to heat in its internal pipes and components. This periodic displacement is an objective physical law. Therefore, sealing devices capable of accommodating this displacement must be installed between the boiler's fixed structure and moving parts, such as at pipe penetrations and expansion joints in the boiler wall.

[0003] Early sealing structures often employed rigid or semi-rigid designs, such as asbestos rope packing or simple metal casings. While these structures might maintain a short-term seal for minor displacements, they are highly susceptible to cracking and loosening due to material fatigue or stress concentration at joints after larger displacements or increased cycles, ultimately leading to seal failure. Seal failure results in flue gas leakage, reducing boiler thermal efficiency and posing safety and environmental hazards. The fundamental reason is that rigid structures have limited deformation capacity and cannot effectively track and compensate for continuous dynamic displacements.

[0004] To address the shortcomings of rigid seals, flexible sealing technology has gradually been adopted. Sealing elements made from flexible materials, such as ordinary fiber fabrics or rubber-coated fabrics, have improved deformability. However, these basic flexible structures still face a series of inherent challenges in the harsh operating environment of boilers.

[0005] First, there is the issue of material durability. Boiler operating areas are typically characterized by high temperatures, and the flue gas may contain corrosive components and dust particles. Flexible materials exposed to this environment for extended periods are prone to aging, hardening, and embrittlement, gradually diminishing their mechanical strength and elasticity. More critically, even if the material itself possesses a certain degree of temperature resistance, improper structural design can severely impact its service life. For example, in simple cylindrical or pleated flexible sleeves, stress is not uniformly distributed during repeated stretching, compression, and bending deformation, often concentrating in specific areas, such as the roots of pleats or the connection to rigid mounting edges. This localized stress concentration significantly accelerates material fatigue damage, causing cracks or even tears to form at these weak points before the overall material has fully aged. Addressing uniform deformation and avoiding stress concentration is a core challenge in the design of flexible sealing structures.

[0006] Secondly, there is the issue of displacement compensation matching. The thermal displacement of boiler piping is three-dimensional, potentially involving combined axial, radial, and even angular movements. While conventional bellows structures provide axial flexibility, their ability to compensate for radial displacement is often weak, and their stiffness characteristics may be consistent in all directions, which does not perfectly match the directional displacement patterns in actual operating conditions. A sealing element with uniform stiffness in all directions may generate unnecessary excessive stress in some directions and insufficient compensation in others when dealing with asymmetric displacement. Designing a structure that can more intelligently and efficiently adapt to such multi-directional and asymmetric actual displacement, rather than passively deforming in a single direction, is another technical challenge.

[0007] Furthermore, the reliability of the installation interface is also a challenge. The flexible sealing body needs to be reliably connected to the rigid boiler liner or frame. This connection interface is the transition point between rigidity and flexibility, a point of abrupt change in structure and stress. If the transition design is inappropriate, such as using a simple right-angle bend, dynamic loads will be repeatedly applied to this point, easily causing material peeling or loosening of fasteners at the connection, becoming the breakthrough point for seal failure. Therefore, how to achieve a smooth mechanical transition from the rigid installation edge to the flexible body, and effectively disperse and absorb the stress at the interface, is the key to ensuring the long-term stable operation of the entire sealing device, and also a design challenge. Summary of the Invention

[0008] One object of this invention is to solve at least the aforementioned problems and / or defects, and to provide at least the advantages described below.

[0009] One objective of this invention is to solve the problem of fatigue cracking and leakage of sealing elements caused by thermal displacement of boiler pipes.

[0010] One objective of this invention is to solve the problem that the transition zone is prone to tearing at the root due to abrupt changes in stiffness.

[0011] One objective of this invention is to optimize the stress distribution gradient and deformation compatibility in the transition zone.

[0012] One objective of this invention is to solve the problem of insufficient high-temperature resistance and initial flexibility of the flexible sealing body matrix material.

[0013] One objective of this invention is to solve the problem of material loss on the outer surface of the sealing device caused by flue gas erosion and chemical corrosion.

[0014] One objective of this invention is to solve the problem of instantaneous structural damage to sealing devices caused by mechanical interference or excessive displacement under abnormal operating conditions.

[0015] One objective of this invention is to solve the problem that the corrugated pipe structure is prone to instability and collapse at the trough when subjected to negative pressure or external extrusion.

[0016] One objective of this invention is to ensure that the metal reinforcing ring can perform its reinforcing function most effectively and to avoid introducing new stress concentration points.

[0017] In order to achieve these objectives and other advantages according to the present invention, a flexible sealing device for boilers is provided, comprising an annular sealing body made of flexible high-temperature resistant fiber fabric, wherein the annular sealing body has a bellows structure with its two ends radially outwardly turned to form an annular mounting edge. The corrugated pipe structure is composed of multiple alternating annular troughs and multiple annular peaks, wherein the bottom wall thickness of the annular trough is greater than the top wall thickness of the annular peak. The radius of curvature of the annular trough is greater than the radius of curvature of the annular peak. The root of the mounting edge is connected to the adjacent annular peak or annular trough through a transition zone; the outline of the transition zone is wavy.

[0018] Preferably, in the flexible sealing device for boilers, the outline of the transition zone is smoothly connected by a first arc segment and a second arc segment. The first arc segment is directly connected to the root of the mounting edge, and the second arc segment is directly connected to the annular crest or annular trough. The radius of curvature of the first arc segment is not equal to the radius of curvature of the second arc segment, and the connection point between the first arc segment and the second arc segment is offset from the line connecting the center points of the two ports of the transition zone.

[0019] Preferably, in the flexible sealing device for boilers, the radius of curvature of the first arc segment is greater than the radius of curvature of the second arc segment.

[0020] Preferably, in the flexible sealing device for boilers, the flexible high-temperature resistant fiber fabric is ceramic fiber cloth or glass fiber cloth coated with silicone rubber.

[0021] Preferably, in the flexible sealing device for boilers, the outer surface of the annular sealing body is covered with a wear-resistant and corrosion-resistant coating, which is formed by curing polytetrafluoroethylene or silicon carbide coating.

[0022] Preferably, in the flexible sealing device for boilers, an annular metal protective mesh cover is fitted over the annular sealing body, and the metal protective mesh cover is fixedly connected to the mounting edge.

[0023] Preferably, in the flexible sealing device for boilers, the mesh diameter of the metal protective mesh cover is smaller than the wave pitch of the corrugated pipe structure.

[0024] Preferably, in the flexible sealing device for boilers, an annular metal reinforcing ring is fixed to the inner wall of the annular trough, and the cross-section of the metal reinforcing ring is circular.

[0025] Preferably, in the flexible sealing device for boilers, the metal reinforcing ring is embedded in the center of the bottom of the annular trough, and its outer surface is fitted and fixed to the inner curved surface of the annular trough.

[0026] This utility model has at least the following beneficial effects: This invention employs a corrugated pipe structure with a specific wall thickness distribution and curvature relationship, combined with a wavy transition zone, enabling the sealing device to undergo smoother and more coordinated deformation when the boiler pipe experiences thermal displacement. This structural design helps to distribute deformation stress more evenly throughout the entire sealing body, rather than concentrating it in a few localized areas, thereby slowing down the material fatigue process. The result is an improved adaptability and service life of the sealing device under cyclic displacement conditions, maintaining a more durable sealing effectiveness.

[0027] The transition zone of this invention employs an asymmetrical profile formed by smoothly connected arc segments with varying radii of curvature, resulting in a gradient change in stiffness within this region. When the sealing device deforms, this design guides a more gradual increase or decrease in stress within the transition zone, preventing abrupt changes in stiffness at the connection between the rigid mounting edge and the flexible bellows. This reduces stress concentration in this critical connection area, effectively preventing premature fatigue cracking at the root of the transition zone due to stress concentration.

[0028] This invention creates a clear transition sequence from relative rigidity to relative flexibility by setting the radius of curvature of the first arc segment near the mounting edge to be greater than that of the second arc segment near the bellows. This specific stiffness distribution allows the deformation characteristics of the transition zone to better match the mechanical properties of the connecting components at both ends. It helps to achieve a more optimized stress transmission path, further smooths the stress distribution curve, and thus improves the structural integrity and durability of the transition zone during long-term use.

[0029] This invention uses ceramic fiber cloth or silicone rubber-coated glass fiber cloth as the matrix material, providing a material basis for the sealing device to operate reliably in high-temperature environments. These materials can maintain the stability of their structure and the necessary flexibility within the boiler operating temperature range, avoiding rapid hardening, embrittlement, or decomposition caused by the material's poor temperature resistance, thereby ensuring that the core function of the sealing device can be realized and maintained.

[0030] This invention adds a specific wear-resistant and corrosion-resistant coating to the outer surface of the sealing body, providing an effective protective barrier for the base material. This barrier can directly withstand the erosion of dust particles in flue gas and the corrosion of chemicals, reducing the direct damage to the base material caused by these factors. This helps maintain the integrity and mechanical properties of the base material, extending the service life of the sealing device in harsh flue gas environments.

[0031] This invention adds a metal protective mesh cover to the outside of the sealing body, providing it with a layer of mechanical protection. This mesh cover can resist accidental impacts or interference from external foreign objects, and also plays a certain mechanical limiting role when the sealing body experiences excessive displacement. This design reduces the risk of instantaneous mechanical damage to the sealing body and enhances the reliability and safety of the entire sealing device under complex operating conditions.

[0032] This invention incorporates a circular metal reinforcing ring on the inner wall of the annular trough, significantly enhancing the circumferential stiffness and deformation resistance of the trough. This reinforcement helps the trough resist collapse when subjected to internal negative pressure or external extrusion, maintaining the shape stability of the bellows channel and thus ensuring unobstructed airflow and proper sealing.

[0033] This invention precisely embeds a metal reinforcing ring in the center of the trough bottom and ensures it fits snugly against the inner curved surface, guaranteeing that the reinforcing ring is in the most effective load-bearing position. This installation method allows the supporting force provided by the reinforcing ring to be evenly transmitted throughout the entire trough through the maximum lever arm, optimizing the force transmission path and avoiding localized stress anomalies that may be caused by improper positioning of the reinforcing ring, resulting in a more thorough and reliable reinforcement effect.

[0034] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the flexible sealing device for boilers in this utility model.

[0036] Figure 2 This is a schematic diagram of the cross-section of the peak of the annular wave in this utility model.

[0037] Figure 3 This is a schematic diagram of the cross-section of the bottom of the annular wave valley in this utility model. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0039] like Figures 1 to 3 As shown, this utility model provides a flexible sealing device for boilers, including an annular sealing body made of flexible high-temperature resistant fiber fabric. The annular sealing body has a bellows structure with radially outward flanges at both ends forming annular mounting edges 5. The bellows structure consists of multiple alternating annular troughs 3 and multiple annular peaks 1. The wall thickness of the valley bottom 4 of the annular trough 3 is greater than the wall thickness of the peak 2 of the annular peak 1. The radius of curvature of the annular trough 3 is greater than the radius of curvature of the annular peak 1. The root of the mounting edge 5 is connected to the adjacent annular peak 1 or annular trough 3 through a transition zone 8. The outline of the transition zone 8 is wavy.

[0040] The specific implementation of this utility model is as follows: The core component of this flexible sealing device for boilers is an annular sealing body, which is made of flexible high-temperature resistant fiber fabric. Its annular wall is constructed in the shape of a bellows, which consists of a series of alternating and continuously connected annular troughs 3 and annular crests 1. A key design feature is that the wall thickness of the valley bottom 4 in the annular trough 3 region is made greater than the wall thickness of the peak 2 in the annular crest 1 region. At the same time, the radius of curvature of the annular trough 3 is also greater than the radius of curvature of the annular crest 1. At both ends of the annular sealing body, its edges are radially folded outward to form annular mounting edges 5. The root of the mounting edge 5 is not directly connected to the bellows, but is connected to the adjacent annular crest 1 or annular trough 3 through a transition area 8 with a wavy profile.

[0041] The ratio T1:T2 of the wall thickness T1 at the bottom 4 of the annular trough 3 to the wall thickness T2 at the peak 2 of the annular crest 1 is between 1.3:1 and 2.0:1, preferably 1.5:1. This design allows the trough to provide stronger support stiffness under axial compression, while the crest is more prone to bending deformation under tension, thus achieving a uniform overall stress distribution. The ratio Rg:Rf of the surface radius Rg of the annular trough 3 to the surface radius Rf of the annular crest 1 is between 1.8:1 and 3.5:1, preferably 2.5:1. The larger trough curvature radius effectively reduces local bending stress at that location, and in synergy with the increased wall thickness, significantly improves the fatigue resistance of the trough.

[0042] Existing technologies typically employ bellows structures made of flexible materials to achieve sealing and displacement compensation. However, these bellows structures often have uniform wall thickness and symmetrical waveform profiles. This homogeneous and symmetrical design inevitably leads to stress concentrations at curvature changes such as crests and troughs when subjected to cyclic stress, which can easily become the initiation points of fatigue cracks over long-term exposure. Furthermore, the transition zone 8 between the mounting edge 5 and the bellows body is usually quite simple, such as using a single circular arc transition. Under complex multi-directional displacement, this structure is prone to generating high stress at the root, leading to premature failure at the connection.

[0043] This invention employs a corrugated design with thickened troughs and an asymmetric radius of curvature to alter the stiffness distribution of the pipe wall, allowing stress to be more evenly dispersed during deformation and thus slowing down the local fatigue process. The wave-shaped transition zone 8, compared to a simple circular arc transition, provides a smoother stiffness gradient, helping to reduce stress concentration at the installation root. These structural improvements aim to enhance the adaptability and service life of the sealing device under complex boiler operating conditions.

[0044] In a preferred embodiment, in the flexible sealing device for boilers, the outline of the transition zone 8 is smoothly connected by a first arc segment 9 and a second arc segment 10. The first arc segment 9 is directly connected to the root of the mounting edge 5, and the second arc segment 10 is directly connected to the annular crest 1 or annular trough 3. The radius of curvature of the first arc segment 9 is not equal to the radius of curvature of the second arc segment 10, and the connection point of the first arc segment 9 and the second arc segment 10 is offset from the line connecting the center points of the two ports of the transition zone 8.

[0045] In this embodiment, the specific outline of the transition zone 8 is formed by a smooth connection of a first arc segment 9 and a second arc segment 10. One end of the first arc segment 9 is directly connected to the root of the mounting edge 5, while its other end is seamlessly connected to the second arc segment 10. The end of the second arc segment 10 is directly connected to the adjacent annular crest 1 or annular trough 3. An important feature is that the radius of curvature of the first arc segment 9 and the radius of curvature of the second arc segment 10 are set to be unequal. Furthermore, the connection point between the first arc segment 9 and the second arc segment 10 is spatially offset from the line connecting the center points of the two ends of the transition zone 8.

[0046] The wavy transition zone 8 may contain various irregular wave curves, and its stiffness change path may not be ideal. This invention addresses this by combining two circular arc segments with different radii of curvature and ensuring that their connection point is off-center from the centerline, thereby constructing a clear, asymmetric stiffness gradient path within the transition zone 8. This design makes the mechanical transfer from the rigid mounting edge 5 to the flexible bellows smoother, helping to more effectively guide and disperse stress, thus further reducing the risk of fatigue cracks at the root of the transition zone 8 due to abrupt stiffness changes.

[0047] In a preferred embodiment, in the flexible sealing device for boilers, the radius of curvature of the first arc segment 9 is greater than the radius of curvature of the second arc segment 10.

[0048] In this embodiment, the first arc segment 9 and the second arc segment 10 constituting the transition zone 8 have a specific curvature relationship, that is, the radius of curvature of the first arc segment 9 is set to be greater than the radius of curvature of the second arc segment 10. This makes the contour of the transition zone 8 present a relatively gentle and smooth shape near the mounting edge 5, while the part near the bellows is relatively compact and curved. The ratio R1:R2 of the radius of curvature R1 of the first arc segment 9 to the radius of curvature R2 of the second arc segment 10 is between 1.5:1 and 3.0:1, preferably 2.0:1. For example, R1 can be 20mm and R2 can be 10mm. This asymmetrical double arc structure with a clear gradient difference together constitutes the "wavy" contour, and its connection point is significantly deviated from the line connecting the center points of the two ends of the transition zone 8. This design allows for a smooth transition in structural stiffness from the rigid mounting edge 5 to the flexible corrugated pipe, rather than an abrupt change. Finite element analysis has verified that the maximum stress at the root of the transition zone 8 is reduced by more than 30% compared to the traditional single large circular arc transition structure, effectively solving the problems of stress concentration and easy tearing at the root.

[0049] This invention creates a directional stiffness transition from relative rigidity to relative flexibility by specifically constructing the transition zone 8 into an asymmetrical form with a gentle inlet section and a compact outlet section. This specific stiffness distribution aims to better match the deformation characteristics of the transition zone 8 with the actual mechanical relationship between the rigid mounting edges 5 connected to its two ends and the flexible bellows, thereby potentially achieving a smoother stress transition and further improving the durability of this part under long-term cyclic loading.

[0050] In a preferred embodiment, the flexible high-temperature resistant fiber fabric in the boiler flexible sealing device is ceramic fiber cloth or glass fiber cloth coated with silicone rubber.

[0051] In this embodiment, the annular sealing body is made of one of two specific materials: ceramic fiber cloth or glass fiber cloth with a silicone rubber coating.

[0052] The flexible, high-temperature resistant fiber fabric is a multi-layered, stitched ceramic fiber cloth, capable of long-term use at temperatures exceeding 1000℃ while maintaining excellent flexibility. The wear-resistant and corrosion-resistant coating is a polytetrafluoroethylene (PTFE) coating applied to the outer surface of the sealing body via an impregnation-curing process, with a dry film thickness of 0.1~0.3mm. This coating not only resists flue gas corrosion, but its extremely low coefficient of surface friction also helps reduce wear with external components.

[0053] In another preferred embodiment, the flexible high-temperature resistant fiber fabric is a glass fiber cloth coated with silicone rubber. This material is suitable for sealing parts in boiler systems where the temperature is relatively low (typically not higher than 280°C) and where initial airtightness requirements are higher, such as the medium- and low-temperature sections of some boiler flues or the air preheater area. In this embodiment, the annular sealing body is made of the silicone rubber-coated glass fiber cloth by molding or sewing. The silicone rubber layer not only provides excellent initial sealing performance but also maintains good flexibility and elasticity in the medium- and low-temperature range. Correspondingly, the wear-resistant and corrosion-resistant coating is preferably a polytetrafluoroethylene (PTFE) coating, cured on the outer surface of the sealing body by spraying or impregnation, with a dry film thickness of 0.1~0.3 mm. The low surface energy and non-stickiness of the PTFE coating have good compatibility with the silicone rubber matrix and can effectively resist acid dew point corrosion of low-temperature flue gas.

[0054] The ceramic fiber cloth selected in this invention has the ability to withstand high temperatures, while the glass fiber cloth coated with silicone rubber maintains a certain degree of temperature resistance, and its surface silicone rubber layer provides good initial airtightness and a certain degree of flexibility. The selection of these two materials provides a clear and feasible implementation path for manufacturing a flexible sealing body that can maintain its structural integrity and basic sealing function within the common temperature range of boilers.

[0055] In a preferred embodiment, the outer surface of the annular sealing body of the boiler flexible sealing device is covered with a wear-resistant and corrosion-resistant coating, which is formed by curing polytetrafluoroethylene or silicon carbide coating.

[0056] This protective layer is a wear-resistant and corrosion-resistant coating that is formed by applying a polytetrafluoroethylene coating or a silicon carbide coating to the outer surface of the sealed body and allowing it to cure, thereby covering the substrate material.

[0057] Compared to sealing devices without such a coating, the embodiments of this invention offer improvements to address the problems that substrate materials may face in harsh flue gas environments. Uncoated sealing devices, with substrate materials such as ceramic fiber cloth or coated fiberglass cloth, while possessing certain temperature resistance, are directly exposed to flue gas and continuously subjected to erosion from suspended dust particles and chemical corrosion from acidic condensates. These factors directly lead to the gradual wear and performance degradation of the substrate material. This invention, by applying a dense protective coating to the outer surface of the substrate material, makes the coating the first line of defense against wear and corrosion. The polytetrafluoroethylene coating primarily contributes its excellent chemical corrosion resistance and low surface energy characteristics, while the silicon carbide coating mainly provides higher surface hardness to resist particle erosion. This additional coating aims to mitigate the direct damage of environmental factors to the substrate material, thereby helping to maintain the integrity of the substrate material and extend its effective service life.

[0058] In a preferred embodiment, in the flexible sealing device for boilers, an annular metal protective mesh cover 6 is fitted around the annular sealing body, and the metal protective mesh cover 6 is fixedly connected to the mounting edge 5.

[0059] The metal protective mesh cover 6 is fitted over the corrugated pipe structure of the sealing body, and its two ends are fixedly connected to the annular mounting edges 5 at both ends of the sealing body. The metal protective mesh cover 6 is woven from heat-resistant stainless steel wire (such as grade 310S) and fixedly connected to the mounting edges 5 by bolt clamping. The metal reinforcing ring 7 is made of heat-resistant stainless steel round strip (such as grade 321), with a cross-sectional circular diameter of 3~6mm. The reinforcing ring is fixed to the center of the valley bottom 4 of the annular trough 3 by a composite process of high-temperature inorganic adhesive bonding and covering stitching, ensuring that its outer surface is tightly fitted to the curved surface of the inner wall of the trough. This fixing method can adapt to the difference in thermal expansion at high temperature and prevent the reinforcing ring from shifting during dynamic deformation, thereby maximizing its anti-collapse effect and avoiding the introduction of new stress concentration points.

[0060] Compared to sealing devices without external protective structures, this invention introduces an additional mechanical protective layer. The unprotected flexible sealing body is directly exposed within the installation space. When there is loose insulation material or other foreign objects inside the boiler, or during maintenance, it may be scratched, torn, or deformed due to abnormal pressure. This invention constructs an external protective frame by encasing the flexible sealing body in a metal mesh cover connected to a relatively robust mounting edge 5. This mesh cover effectively blocks direct impacts and interference from larger foreign objects and limits excessive deformation of the sealing body. Its purpose is to reduce the risk of accidental damage to the sealing body due to external mechanical causes, thereby improving the reliability of the entire sealing device in actual operating environments.

[0061] In a preferred embodiment, in the flexible sealing device for boilers, an annular metal reinforcing ring 7 is fixed to the inner wall of the annular trough 3, and the cross-section of the metal reinforcing ring 7 is circular.

[0062] In this embodiment, an annular metal reinforcing ring 7 is fixed to the inner wall of the annular trough 3. The cross-sectional shape of the metal reinforcing ring 7 is circular.

[0063] Compared to bellows without internal reinforcement, this invention improves the stability of the troughs under pressure. In an unreinforced flexible bellows, when the internal pressure is lower than the external pressure (i.e., under negative pressure), the pipe wall relies primarily on its own bending stiffness to resist external atmospheric pressure. The annular trough 3, being an inwardly recessed portion of the bellows profile, is prone to local collapse or flattening under these conditions due to instability. This invention, by fixing a circular metal ring to the inner wall of the trough, essentially introduces a built-in annular skeleton into the trough area. This reinforcing ring significantly improves the circumferential stiffness of the trough region, helping it better maintain its original circular profile, thereby enhancing the bellows' overall resistance to radial crushing and contributing to maintaining unobstructed media flow.

[0064] In a preferred embodiment, in the flexible sealing device for boilers, the metal reinforcing ring 7 is embedded in the center of the valley bottom 4 of the annular trough 3, and its outer surface is fitted and fixed to the inner wall curved surface of the annular trough 3.

[0065] In this embodiment, the metal reinforcing ring 7 is embedded in the center of the valley bottom 4 of the annular trough 3, and its outer surface is fixedly attached to the inner wall curved surface of the annular trough 3.

[0066] A reinforcing ring that is not precisely aligned or does not fit adequately against the inner wall of the trough may fail to distribute the supporting force evenly to the entire trough when subjected to external pressure. It may even lead to localized stress anomalies due to uneven stress distribution, thus weakening its reinforcing effect. This invention addresses this by precisely positioning the reinforcing ring in the center of the trough bottom 4—a critical stress-bearing area—and ensuring its outer surface is tightly fitted to the curved surface of the trough's inner wall. This allows the reinforcing ring to be in the optimal load-bearing position. This installation method helps distribute the supporting force provided by the reinforcing ring more evenly across the entire circumference of the trough, thereby more effectively working in conjunction with the trough material to resist deformation and improving the uniformity and reliability of the reinforcing effect.

[0067] Although embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. It can be applied to various fields suitable for this utility model. Other modifications can be readily implemented by those skilled in the art. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and examples shown and described herein.

Claims

1. A flexible sealing device for boilers, characterized in that, It includes an annular sealing body made of flexible high-temperature resistant fiber fabric, wherein the annular sealing body has a bellows structure on its annular wall and its two ends are radially outwardly turned to form an annular mounting edge. The corrugated pipe structure is composed of multiple alternating annular troughs and multiple annular peaks, wherein the bottom wall thickness of the annular trough is greater than the top wall thickness of the annular peak. The radius of curvature of the annular trough is greater than the radius of curvature of the annular crest; The root of the mounting edge is connected to the adjacent annular peak or annular trough through a transition zone; the outline of the transition zone is wavy.

2. The flexible sealing device for boilers according to claim 1, characterized in that, The outline of the transition zone is formed by a smooth connection of a first arc segment and a second arc segment. The first arc segment is directly connected to the root of the mounting edge, and the second arc segment is directly connected to the annular peak or annular trough. The radius of curvature of the first arc segment is not equal to the radius of curvature of the second arc segment, and the connection point of the first arc segment and the second arc segment is offset from the line connecting the center points of the two ends of the transition zone.

3. The flexible sealing device for boilers according to claim 2, characterized in that, The radius of curvature of the first arc segment is greater than the radius of curvature of the second arc segment.

4. The flexible sealing device for boilers according to claim 1, characterized in that, The flexible high-temperature resistant fiber fabric is ceramic fiber cloth or glass fiber cloth coated with silicone rubber.

5. The flexible sealing device for boilers according to claim 4, characterized in that, The outer surface of the annular sealing body is covered with a wear-resistant and corrosion-resistant coating, which is formed by curing polytetrafluoroethylene or silicon carbide coating.

6. The flexible sealing device for boilers according to claim 1, characterized in that, An annular metal protective mesh cover is fitted over the outside of the annular sealing body, and the metal protective mesh cover is fixedly connected to the mounting edge.

7. The flexible sealing device for boilers according to claim 1, characterized in that, The inner wall of the annular trough is fixed with an annular metal reinforcing ring, the cross-section of which is circular.

8. The flexible sealing device for boilers according to claim 7, characterized in that, The metal reinforcing ring is embedded in the center of the bottom of the annular trough, and its outer surface is fixed to the inner curved surface of the annular trough.

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