Composite structure for preventing cracking and smoke leakage of boiler wall plate and construction process thereof

Abstract

This application relates to a composite structure and its construction process for preventing cracking and smoke leakage in boiler wall panels, belonging to the field of boiler equipment maintenance technology. The structure includes a protective plate and an intermediate plate, with the intermediate plate positioned between the old wall panel and the protective plate. One side of the intermediate plate has a connector for inserting into cracks. The connector contains an injection cavity, an injection hole, and a radially expandable support rod, and can be fitted with a thermally expandable elastic ring. During construction, the connector is inserted into the crack, the support rod is anchored, and sealant is injected to fill the gap. The heat from the sealant triggers the elastic ring to expand, enhancing the seal. This application, through a combination of multi-layered panel structure, mechanical anchoring, and chemical sealing, and utilizing smart materials to achieve adaptive compression, effectively solves the problems of stress concentration and poor seal durability in traditional repair methods, achieving long-term and reliable repair of cracks in boiler wall panels.

Description

Technical Field

[0001] This application relates to the field of boiler equipment maintenance technology, and in particular to a composite structure for preventing cracking and smoke leakage in boiler furnace wall panels and its construction process. Background Technology

[0002] As a core piece of equipment in energy conversion and industrial production, boilers are subjected to harsh working environments such as high-temperature flue gas scouring, drastic temperature fluctuations, and cyclical pressure changes for extended periods. The structural integrity of the boiler is directly related to its operational safety and stability.

[0003] During the long-term service of boilers, furnace wall panels are susceptible to cracks due to various factors such as material thermal fatigue, welding stress release, and flue gas corrosion. Once these cracks appear, if they are not addressed in time, they will continue to expand under continuous working loads, not only reducing the structural strength of the furnace wall panels but also potentially causing them to break and leading to safety accidents.

[0004] More importantly, cracks in the furnace wall panels can create channels for flue gas leakage. High-temperature and high-pressure flue gas leaking through these cracks will not only waste energy, but also corrode surrounding boiler equipment, pollute the environment, and even threaten the personal safety of on-site operators.

[0005] Currently, the main methods for dealing with cracks in furnace wall panels are direct welding repair or complete replacement of the damaged wall panel. While welding repair is simple to perform, it easily creates new stress concentrations at the weld site, leading to re-cracking during subsequent use and resulting in poor protective effectiveness. Complete wall panel replacement, on the other hand, suffers from long construction periods, high costs, and significant disruptions to production continuity. Furthermore, some simple protective structures cover cracks with only a single panel, lacking a robust multi-connection design, failing to effectively prevent crack propagation, and resulting in short flue gas leakage paths. This makes it difficult to achieve long-term reliable smoke prevention and cannot meet the requirements for long-term stable boiler operation. Summary of the Invention

[0006] In order to improve the situation in the above-mentioned technology, this application provides a composite structure for preventing cracking and smoke leakage of boiler wall panels and its construction process.

[0007] The technical solution provided in this application for a composite structure and construction process to prevent cracking and smoke leakage in boiler wall panels is as follows: A composite structure for preventing cracking and smoke leakage in boiler wall panels includes a protective plate and an intermediate plate. The intermediate plate is used to cover the cracked areas of the old wall panel. The intermediate plate is disposed between the old wall panel and the protective plate. The side of the intermediate plate facing the old wall panel has a crack joint for connecting with the cracks on the old wall panel. One side of the intermediate plate is connected to the old wall panel through a first connector, and the other side is connected to the protective plate through a second connector.

[0008] In the implementation of the above technical solution, the composite structure for preventing cracking and smoke leakage in boiler wall panels can repair cracked old wall panels. The crack joint first combines with the crack in the old wall panel to achieve initial positioning and sealing. At this time, the intermediate plate, as the core functional layer, covers the crack area. Subsequently, a first layer of connection is established between the intermediate plate and the old wall panel through the first connector, achieving a stable combination with the old structure and forming a first layer of stable connection to lock the crack area and prevent further crack expansion. A second layer of connection is established between the intermediate plate and the protective plate through the second connector, forming an external active protective barrier. Under the combined action of these two connection structures, the path of high-temperature flue gas escaping from the crack in the old wall panel is significantly lengthened and becomes tortuous. It must pass through the connection interface between the intermediate plate and the protective plate, the connection interface between the intermediate plate and the old wall panel, and the crack joint in sequence. The leakage path of the flue gas changes from a single gap to a tortuous channel between the "old wall panel-intermediate plate-protective plate", thereby greatly increasing the leakage resistance and effectively preventing flue gas leakage.

[0009] The intermediate plate acts as a buffer and stress-dispersing element between the old wall panel and the protective plate, preventing the stress on the protective plate from being directly transmitted to the cracks in the old wall panel, which would exacerbate the cracking. The protective plate is designed as the outermost layer that directly withstands the scouring and corrosion of high-temperature flue gas. It is made of high-temperature resistant material suitable for the boiler's working environment. Its core function is that, during long-term use, when the protective plate is damaged or develops new cracks due to extreme working conditions, it can be replaced by simply removing the second connector without disturbing the intermediate plate that is already firmly bonded to the old wall panel. This greatly simplifies the maintenance process, reduces maintenance costs and downtime, and achieves a balance between maintainability and long service life. It systematically solves the problems of crack prevention and smoke leakage prevention of the furnace wall panel from a structural perspective.

[0010] Optionally, the crack joint includes a plug for inserting into the crack in the old wall panel. The plug is disposed on the side of the intermediate plate facing the old wall panel. The plug has a plurality of glue outlet holes circumferentially opened on the plug. The intermediate plate has an glue injection channel communicating with the glue outlet holes. The protective plate is provided with a sealing member for sealing the glue injection channel.

[0011] In the implementation of the above technical solution, during installation, the plug-in seat of the middle plate facing the old wall panel is first inserted into the crack of the old wall panel to achieve preliminary physical filling and positioning of the crack. Then, the middle plate is connected to the old wall panel through the first connector to keep the plug-in seat stably limited in the crack and prevent displacement. After that, sealant is injected into the plug-in seat through the injection channel opened on the middle plate. The sealant flows along the injection channel to the plug-in seat and overflows evenly from the multiple outlet holes opened around it. The flowing sealant first fully fills all the gaps between the outer wall of the plug-in seat and the inner wall of the crack, and then further penetrates and fills the micro-pores of the crack itself, finally forming a dense seal with excellent wrapping properties around the plug-in seat and inside the crack. After the sealant injection is completed, wait for the fluidity of the sealant to decrease slightly (the sealant can be in a semi-cured or cured state), and then connect the protective plate to the middle plate through the second connector. The sealing part on the protective plate tightly seals the injection channel. This process sequence of "mechanical fixing followed by chemical sealing" ensures that the connector position remains stable and does not shift under the injection pressure, allowing the sealant to be evenly distributed. The sealing components on the protective plate tightly seal the injection channel, preventing high-temperature flue gas from entering the injection channel during subsequent boiler operation, which could lead to sealant aging and failure or channel corrosion damage. The resulting composite seal not only effectively blocks the leakage path of flue gas along the crack-connector interface, significantly improving the reliability of the seal, but the cured elastic sealant can also effectively buffer and adapt to the slight displacement caused by the difference in thermal expansion between the old wall panel and the intermediate panel, preventing new stress concentration points due to rigid constraints, thus achieving long-term and reliable smoke leakage prevention repair.

[0012] Optionally, the connector is movably provided with a plurality of support rods, and the connector is provided with a driving member, which is used to drive the plurality of support rods to move along the side wall of the crack in the old wall panel, and the end of the support rod near the crack in the old wall panel is conical.

[0013] In the implementation of the above technical solution, when repairing cracks in old wall panels, after the connector is initially inserted into the crack, the driving component is operated to drive multiple movable support rods mounted on the connector to move synchronously along the direction close to the crack sidewall. During this process, since the end of the support rod away from the connector is conical, its tip, when pressed against the inner wall of the crack, can penetrate and squeeze out the fragile, loose metal oxide layer or impurities that have adhered to the inner wall of the crack due to high-temperature oxidation and long-term thermal stress. This part of the wall material that has been squeezed out will fall into the depth of the crack, thereby exposing the relatively fresh and solid metal matrix on the crack sidewall. This effect not only allows the conical end of the support rod to obtain a more solid mechanical anchoring point, significantly enhancing the pull-out resistance, but also creates better interface conditions for the subsequent sealant injection process: when the sealant is injected through the injection channel and the outlet hole, it can combine with the material particles that have fallen into the crack after being squeezed out by the support rod, and can also achieve a tighter and more stable chemical bond and mechanical integration with the exposed fresh metal matrix. This dual effect ensures an exceptionally strong bond between the sealant and the old wall panel, greatly improving the long-term sealing reliability and integrity of the repaired structure under harsh conditions such as high temperature and vibration.

[0014] Optionally, the connector has multiple receiving slots, and each receiving slot has a support rod that is slidably fitted inside. The driving member includes an elastic part disposed in the receiving slot, one end of which is fixedly connected to the receiving slot, and the other end of which abuts against the end of the support rod away from the crack on the old wall panel.

[0015] In the implementation of the above technical solution, multiple receiving slots on the connector provide dedicated installation and sliding space for the support rod. The support rod slides through the receiving slots to achieve directional movement, and the end of the support rod near the connector connects to the elastic part in the receiving slot. After the connector is inserted into the crack of the old wall panel, the elastic part releases elastic potential energy to generate driving force, pushing the support rod to move smoothly along the receiving slot towards the sidewall of the crack. Since the end of the support rod away from the connector is conical, during the movement, the conical end will press against the sidewall of the crack and disperse some of the loose wall material on it. This dispersed wall material fills the gap inside the crack. During subsequent sealant injection, the sealant flows into the connector through the injection channel and overflows from the outlet hole, which not only fills the connector but also... All gaps between the strut and the crack sidewall are fully bonded to the loose wall material, making the sealant more stable in connection with the crack sidewall. The elastic part not only realizes the automatic drive of the strut without the need for an additional complex drive mechanism, simplifying the structure, but also absorbs the stress caused by temperature changes during boiler operation through its own elastic deformation, avoiding the breakage of the strut or secondary cracking of the crack sidewall caused by rigid drive. At the same time, the guiding effect of the receiving groove on the strut ensures the precise movement direction and ensures that the pointed end can effectively anchor the crack sidewall. Finally, through the synergy of "elastic drive + directional sliding + loose material bonding + sealant filling", the reliability and stability of crack prevention and smoke leakage prevention are further improved while simplifying the structure.

[0016] Optionally, the plug-in socket has an injection cavity, and the injection channel and the plurality of injection holes are all connected to the injection cavity; the bottom of the receiving groove has an installation hole, which is connected to the injection cavity; the elastic part includes a spring disposed in the installation hole, one end of the spring is fixedly connected to the installation hole, and the other end abuts against the end of the support rod away from the crack on the old wall panel.

[0017] In the implementation of the above technical solution, during the repair process, when sealant is injected into the injection channel, the sealant first flows into the injection cavity inside the connector and quickly fills the cavity under pressure. Since multiple outlet holes and mounting holes for installing springs are connected to this injection cavity, the sealant then flows through the outlet holes to the crack. Simultaneously, high-pressure sealant also flows into each mounting hole. During this crucial process, the sealant flowing into the mounting holes encapsulates the springs installed within them and directly acts on the inner end of the support rod fixedly connected to the spring's end. This produces a dual benefit: First, the fluid pressure generated by the flowing adhesive, combined with the elasticity of the spring, acts as a driving force, more powerfully and stably pushing the strut outward against friction, ensuring its reliable contact with the crack sidewall; Second, after the adhesive cures in the mounting hole, it solidifies with the spring, the inner end of the strut, and the hole wall into a robust whole. This not only completely "encapsulates and protects" the spring from high-temperature flue gas corrosion, but more importantly, it achieves a rigid and permanent connection between the strut, the spring, and the base of the connector, eliminating any loosening that may be caused by vibration or thermal cycling. This upgrades the strut's locking state from "elastic maintenance" to "rigid locking," thereby greatly enhancing the overall mechanical stability and fatigue resistance of the repair structure and ensuring its long-term reliable service.

[0018] Optionally, a connecting plate is slidably disposed in the receiving groove, and the support rod is connected to the elastic part through the connecting plate. One side of the connecting plate is connected to the support rod, and the other side abuts against the other end of the elastic part. A mating block is provided on the connecting plate, and the mating block and the support rod are disposed on the same side of the connecting plate. An elastic ring is provided on the plug seat, and the inner wall of the elastic ring abuts against the mating block.

[0019] In the implementation of the above technical solution, during the initial stage of inserting the connector into the crack, the elastic ring, due to its inner wall abutting against the mating block on the connecting plate, applies a centripetal and uniform radial constraint force to all connecting plates and their connected struts, reliably retracting all struts into the receiving groove and ensuring smooth insertion of the connector. Once the connector is in place, the elastic ring releases its constraint on the mating block. At this time, the elastic part in the receiving groove releases its pre-stored elastic potential energy, pushing the connecting plate to slide outward along the receiving groove, thereby causing all struts to extend radially synchronously and stably, ensuring their pointed ends firmly abut against the crack sidewall. During this process, the connecting plate, as a rigid force transmission and synchronization component, ensures the consistency of movement and uniform force distribution of multiple struts driven by the elastic part, avoiding asynchronous movement caused by friction or jamming of individual struts. The elastic ring provides an integrated, one-time release collective limiting mechanism, making the initial retraction state of the struts more stable and the release operation simpler and faster, thus significantly improving the efficiency and reliability of on-site construction.

[0020] Optionally, the elastic ring is made of a material with thermal expansion properties, and part of the outlet of the glue outlet is disposed facing the inner wall of the elastic ring.

[0021] In the implementation of the above technical solution, after the connector is in place, the elastic ring is pulled radially away from the support rod along the connector, causing the elastic ring to separate from the mating block and releasing the elastic ring from the mating block. The elastic ring is pulled to partially or completely block the glue outlet, and the outlet of this partially blocked or partially blocked glue outlet faces the inner wall of the elastic ring. When the sealant with a certain temperature is injected subsequently, the sealant is diverted through the injection channel and injection cavity. Part of it overflows directly from the outlet towards the outlet hole on the inner wall of the elastic ring, filling the gap between the elastic ring and the side wall of the crack and the outer wall of the connector. The other part fills the remaining gap between the connector and the crack from other outlet holes. The heat of the sealant triggers the elastic ring to expand. After expansion, the elastic ring fits tightly against the side wall of the crack and the outer wall of the connector, making full contact with and firmly bonding with the sealant flowing through the outlet hole on the inner wall. After the sealant cures, the mechanical locking of the elastic ring due to thermal expansion and the chemical bonding of the sealant form a dual structure. This structure prevents the gap rebound caused by the aging and shrinkage of the sealant through the expansion tension of the elastic ring. The outlet hole on the inner wall allows the sealant to directly fill the tiny gaps between the elastic ring and each contact surface, strengthening the connection of the dual structure. At the same time, the pre-tightening and expansion of the elastic ring, together with the anchoring effect of the support rod, further improves the long-term reliability of crack prevention and smoke leakage prevention.

[0022] Optionally, the elastic ring includes a main ring body and a plurality of branch segments sleeved on the plug-in base. The outlet of a portion of the adhesive outlet is disposed facing the inner wall of the main ring body. The main ring body and the plurality of branch segments are both made of a material with thermal expansion properties. The plurality of branch segments are disposed at intervals along the circumference of the main ring body on the outer wall of the main ring body. The branch segments extend away from the plug-in base and are disposed at an angle.

[0023] In the implementation of the above technical solution, the elastic ring consists of a main ring body fitted onto the connector and multiple branch segments, both of which possess thermal expansion properties. The multiple branch segments are distributed circumferentially along the outer wall of the main ring body and extend obliquely away from the connector. Some of the adhesive outlet holes face the inner wall of the main ring body. When the connector is inserted into the crack in the old wall panel, the elastic part pushes the connecting plate, causing the support rod to move synchronously. The conical end of the support rod presses against the crack sidewall and disperses loose wall material. Simultaneously, the elastic ring initially forms a preliminary fit with the crack sidewall. When sealant with a certain temperature is subsequently injected, the sealant is diverted through the injection channel and injection cavity. Part of it flows out from the outlet holes facing the inner wall of the main ring body, filling the gap between the main ring body, the outer wall of the connector, and the crack sidewall; the other part flows out from... Other dispensing holes fill the remaining areas of the crack; the heat of the sealant triggers the synchronous thermal expansion of the main ring and the support petals. The main ring tightly fits the outer wall of the connector and the main side wall of the crack, while the inclined support petals elastically deform and embed themselves into the gaps or depressions of the crack, eliminating blind spots in the fit; after the sealant cures, the thermal expansion of the main ring mechanically locks and the chemical bonding of the sealant to form a dual structure. The inclined support petals further fill the gaps of irregular cracks, preventing the gaps from rebounding due to the aging and shrinkage of the sealant, and strengthening the overall structural stability through the embedded support of the support petals. At the same time, the design of the dispensing holes facing the inner wall of the main ring ensures that the sealant and the main ring fully contact and bond, ultimately significantly improving the adaptability to irregular cracks and the comprehensiveness and reliability of crack prevention and smoke leakage prevention.

[0024] Optionally, the outer wall of the elastic ring is provided with an annular groove and an axial flow guide groove along the circumferential direction, and the annular groove and the axial flow guide groove are interconnected.

[0025] In the implementation of the above technical solution, the interconnected design of the annular groove and the axial guide groove allows the sealant to fully cover the outer wall of the elastic ring and form a "mechanical interlock" within the groove. After the sealant cures, the thermal expansion mechanical locking of the elastic ring and the "adhesion + embedding" of the sealant form a double reinforcement structure, which not only significantly improves the connection between the elastic ring and the sealant and effectively prevents the sealant from peeling off from the elastic ring under high temperature conditions, but also extends the flue gas leakage path and further enhances the long-term reliability of crack prevention and smoke leakage prevention.

[0026] A construction process for a composite structure for preventing cracking and smoke leakage in boiler wall panels, used for the construction of the aforementioned composite structure for preventing cracking and smoke leakage in boiler wall panels, characterized by including the following steps; S1. On-site preparation and positioning: Determine the area to be repaired, and align the intermediate plate and the plug-in socket set on it with the crack; S2. Preliminary anchoring and sealing: Insert the connector into the crack in the old wall panel; S3. Interface pretreatment and enhancement: High-pressure gas is introduced into the connector through the glue injection channel to purge and clean the inner wall of the crack; then, sealant is injected into the glue injection channel, and the sealant flows out through the glue outlet to fill the crack, the gap between the connector and the crack sidewall. S4. Curing and Assembly: After the sealant's fluidity decreases, the intermediate plate and the old wall panel are fastened together sequentially through the first connector, and then the protective plate is connected to the intermediate plate through the second connector. The sealing component tightly seals the sealant injection channel, completing the installation of the composite structure.

[0027] In summary, this application includes at least one of the following beneficial technical effects: 1. Achieve multi-layer sealing: Through the three-layer composite structure of old wall panel-intermediate panel-protective panel, the path of flue gas leakage is significantly extended, greatly improving the reliability of smoke prevention; 2. Adaptable to irregular cracks: The elastic main ring body + inclined branches can adapt to irregular shapes such as crack bifurcation and depression, eliminating blind spots in the fit; 3. Double-reinforced seal: The elastic ring's thermal expansion mechanical locking is combined with the sealant's chemical bonding to prevent the sealant from aging and shrinking, which could cause the gap to spring back. 4. Adaptive anchoring: The pointed tip of the strut penetrates the sidewall of the crack and disperses loose material, providing a better bonding base for the sealant; 5. High construction efficiency: The overall process involves fewer steps and is simple to operate. It does not require large equipment and is suitable for rapid on-site repair. Attached Figure Description

[0028] Figure 1 This is an overall schematic diagram of a composite structure for preventing cracking and smoke leakage in a boiler wall panel according to Embodiment 1 of this application; Figure 2 yes Figure 1 Enlarged view of section A; Figure 3 This is a bottom view of Embodiment 1 of this application; Figure 4 yes Figure 3 Sectional side view below section line AA; Figure 5 yes Figure 3 Sectional side view below the BB section line; Figure 6 yes Figure 5 Enlarged view of section B; Figure 7 This is a schematic diagram of the interaction between the strut, connecting plate, mating block, and spring in Embodiment 1 of this application; Figure 8 This is embodiment 2 of the present application. Figure 4 A diagram illustrating the state; Figure 9 This is a schematic diagram of the elastic ring in Embodiment 3 of this application; Figure 10 This is a partial cross-sectional side view of the elastic ring in Embodiment 3 of this application.

[0029] Explanation of reference numerals in the attached drawings: 1. Protective plate; 2. Intermediate plate; 3. First connector; 301. First screw; 4. Second connector; 401. Second screw; 5. Plug-in socket; 6. Glue outlet hole; 7. Glue injection channel; 8. Sealing component; 801. Sealing rod; 9. Support rod; 10. Receiving groove; 11. Spring; 12. Glue injection cavity; 13. Mounting hole; 14. Mounting plate; 15. Connecting plate; 16. Mating block; 17. Elastic ring; 171. Main ring body; 172. Support; 18. Annular groove; 19. Axial guide groove; 20. Anti-slip strip; 21. First ring body; 22. Second ring body; 23. First glue hole; 24. Second glue hole; 25. First connecting hole; 26. First part; 27. Second part. Detailed Implementation

[0030] The following combination Figures 1-10 This application will be described in further detail. Example 1

[0031] Embodiment 1 of this application discloses a composite structure for preventing cracking and smoke leakage in boiler wall panels. (Refer to...) Figures 1-7 The composite structure for preventing cracking and smoke leakage in boiler wall panels includes a protective plate 1 and an intermediate plate 2. The intermediate plate 2 is used to cover the cracked area of ​​the old wall panel. The intermediate plate 2 is set between the old wall panel and the protective plate 1. The side of the intermediate plate 2 facing the old wall panel is provided with a crack joint for connecting with the cracks on the old wall panel. One side of the intermediate plate 2 is connected to the old wall panel through a first connector 3, and the other side is connected to the protective plate 1 through a second connector 4.

[0032] Reference Figures 1-7 The crack joint includes a plug seat 5 for inserting into the crack in the old wall panel. The plug seat 5 is located on the side of the intermediate plate 2 facing the old wall panel. The plug seat 5 has multiple glue outlet holes 6 circumferentially opened. The intermediate plate 2 has a glue injection channel 7 communicating with the glue outlet holes 6. The protective plate 1 is provided with a sealing member 8 for sealing the glue injection channel 7.

[0033] Reference Figures 1-7 Multiple support rods 9 are movably provided on the plug-in base 5. A driving component is provided on the plug-in base 5. The driving component is used to drive the multiple support rods 9 to move along the side wall close to the crack in the old wall panel. The end of the support rod 9 close to the crack in the old wall panel is conical.

[0034] Reference Figures 1-7The connector 5 has multiple receiving slots 10, and a support rod 9 is slidably fitted in each receiving slot 10. The driving component includes an elastic part disposed in the receiving slot 10. One end of the elastic part is fixedly connected to the receiving slot 10, and the other end abuts against the end of the support rod 9 away from the crack on the old wall panel.

[0035] Reference Figures 1-7 The plug-in socket 5 has an injection cavity 12, and the injection channel 7 and multiple injection holes 6 are all connected to the injection cavity 12. The bottom of the receiving groove 10 has an installation hole 13, which is connected to the injection cavity 12. The elastic part includes a spring 11 disposed in the installation hole 13. One end of the spring 11 is fixedly connected to the installation hole 13, and the other end is fixedly connected to the end of the support rod 9 away from the crack on the old wall panel.

[0036] Reference Figures 1-7 In this embodiment of the application, in order to facilitate the installation of the spring 11, a plurality of mounting plates 14 are fixed circumferentially on the inner wall of the mounting hole 13. The end of the spring 11 is fixedly connected to one mounting plate 14, and the remaining mounting plates 14 are used to abut against the spring 11 to prevent the spring 11 from dislodging from the mounting hole 13.

[0037] Reference Figures 1-7 A connecting plate 15 is slidably disposed in the receiving groove 10. The support rod 9 is connected to the elastic part through the connecting plate 15. One side of the connecting plate 15 is connected to the support rod 9, and the other side abuts against the other end of the elastic part. A mating block 16 is provided on the connecting plate 15. The mating block 16 and the support rod 9 are disposed on the same side of the connecting plate 15. An elastic ring 17 is provided on the plug seat 5. The outlet of part of the glue outlet 6 is disposed facing the inner wall of the elastic ring 17. The inner wall of the elastic ring 17 abuts against the mating block 16.

[0038] Reference Figures 1-7 In Embodiment 1 of this application, a raised anti-slip strip 20 is fixed on the side of the mating block 16 facing the elastic ring 17. The distance from the anti-slip strip 20 to the connecting plate 15 is slightly less than the distance from the farthest end of the support rod 9 to the connecting plate 15.

[0039] Reference Figures 1-7In Embodiment 1 of this application, the plug-in base 5 is fitted with a plurality of elastic rings 17 along the axial direction. Along the axial direction of the plug-in base 5, with the position of the mating block 16 as the dividing line, there are elastic rings 17 on both sides of the dividing line (for easy distinction, the elastic ring 17 between the intermediate plate 2 and the mating block 16 is named the first ring body 21, and the elastic ring 17 on the other side of the dividing line is named the second ring body 22). Among the glue outlet holes 6 opened on the plug-in base 5, at least some of the glue outlet holes 6 are set towards the inner wall of the first ring body 21, and at least some of the glue outlet holes 6 are set towards the inner wall of the second ring body 22 (for easy distinction, the glue outlet hole 6 corresponding to the first ring body 21 is named the first glue hole 23, and the glue outlet hole 6 corresponding to the second ring body 22 is named the second glue hole 24). In the initial stage of inserting the connector 5 into the crack, the inner wall of the first ring 21 abuts against the mating block 16 on the connecting plate 15, and applies a centripetal and uniform radial constraint force to all connecting plates 15 and their connected support rods 9, reliably gathering all support rods 9 within the receiving groove 10, ensuring that the connector 5 is smoothly inserted. The second ring 22 abuts against the outer wall of the connector 5 to cover the second glue hole 24. After the connector 5 is in place, the first ring 21 is pulled outward, so that the first ring 21 releases the constraint on the mating block 16, and the first ring 21 is pulled to the position that covers the first glue hole 23, thereby facilitating the subsequent glue injection operation.

[0040] Reference Figures 1-7 To further improve the tightness of the sealant bond with the cracks on the old wall panel, the injection channel 7 is extended axially and passes through the plug-in seat 5. The injection channel 7 is equipped with an injection tube (not shown in the figure) for injecting sealant. The injection tube can be inserted into the cracks on the old wall panel through the injection channel 7, and the sealant can be injected gradually from the inside to the outside through the injection tube.

[0041] Reference Figures 1-7 The elastic ring 17 includes a main ring body 171 sleeved on the plug seat 5 and a plurality of branches 172. The outlet of part of the glue outlet 6 is arranged facing the inner wall of the main ring body 171. The main ring body 171 and the plurality of branches 172 are both made of a material with thermal expansion properties. The plurality of branches 172 are arranged circumferentially on the outer wall of the main ring body 171. The branches 172 extend away from the plug seat 5 and are inclined (inclined radially outward relative to the main ring body 171 by 30°-60°).

[0042] Reference Figures 1-7The intermediate plate 2 has multiple through first connecting holes 25. On the side of the intermediate plate 2 away from the old wall panel, there is a chamfer (not shown in the figure) for glue injection that communicates with the first connecting holes 25. The first connecting member 3 includes a first screw 301 threadedly connected to the first connecting holes 25. The protective plate 1 has multiple through second connecting holes (not shown in the figure), and the intermediate plate 2 has multiple mating holes (not shown in the figure, mating holes do not penetrate the intermediate plate 2). Each second connecting hole corresponds to one mating hole. When the protective plate 1 and the intermediate plate 2 are mated, each second connecting hole communicates with one mating hole. The second connecting member 4 includes a second screw 401, which is simultaneously threadedly connected to the corresponding communicating second connecting hole and mating hole. The sealing member 8 includes a sealing rod 801 integrally formed with the protective plate 1. The outer diameter of the sealing rod 801 is adapted to the inner diameter of the glue injection channel 7. When the protective plate 1 and the intermediate plate 2 are connected, the sealing rod 801 is inserted into the glue injection channel 7 to seal the glue injection channel 7.

[0043] The sealant used in this application is a high-temperature resistant and fire-resistant elastic sealant, preferably an organosilicon-based high-temperature resistant sealant or an inorganic ceramic-based fire-resistant sealant. The organosilicon-based sealant is suitable for repairing cracks in the boiler wall panels in the low-temperature section (≤600℃), while the inorganic ceramic-based fire-resistant sealant is suitable for repairing cracks in the boiler wall panels in the high-temperature section (600℃-1200℃). This sealant possesses three core characteristics: high-temperature adhesion, thermal expansion compatibility, and resistance to flue gas corrosion. After curing, its Shore hardness is 40-60HA, and its elongation at break is ≥150%, which can accommodate the slight deformation of the boiler wall panels caused by thermal cycling, preventing the sealant from peeling off from the substrate due to thermal expansion and contraction. Simultaneously, it is resistant to SO2 and NO in boiler flue gas. x Despite being corrosive to various media, it has not shown signs of powdering or cracking during long-term service.

[0044] The injection temperature for silicone-based sealants is 60℃-80℃, while for inorganic ceramic-based sealants it is 80℃-100℃. This temperature range ensures the sealant maintains good fluidity, effectively filling cracks, connectors, and tiny gaps between sidewalls. Furthermore, the heat from the sealant triggers the expansion of the thermal expansion ring, eliminating the need for additional heating equipment and allowing for simultaneous "insertion + expansion." At room temperature (20℃-35℃), the initial curing time is 4-6 hours (until fluidity completely disappears), and the complete curing time is 24 hours. If the ambient temperature at the boiler site is below 10℃, insulation treatment (such as wrapping with insulating cotton) is required for the repaired area, extending the curing time to 36 hours to ensure complete sealant curing and the formation of a dense, bonded sealing layer.

[0045] The intermediate plate 2 is made of medium- and high-temperature heat-resistant steel plate, preferably Q345R(H) heat-resistant pressure vessel steel or 15CrMoR heat-resistant alloy steel plate, with a plate thickness of 8mm-12mm. Among them, Q345R(H) is suitable for the repair of boiler wall panels in the medium and low temperature section, and 15CrMoR is suitable for the repair of boiler wall panels in the high temperature section. This material has high strength, low coefficient of thermal expansion, good weldability and connection, and a tensile strength ≥450MPa at room temperature. Under the long-term service temperature of the boiler, the coefficient of thermal expansion matches that of the boiler wall panel base material (ordinary boiler steel, heat-resistant steel), which can effectively buffer the thermal stress difference between the protective plate and the old wall panel and avoid secondary cracking caused by inconsistent thermal expansion. At the same time, the good weldability can realize the integral molding / welding fixation with the plug-in seat, and the tight fit with the first and second connecting parts is free from deformation and stripping, ensuring connection stability.

[0046] Protective plate 1, as the outer protective structure directly subjected to the scouring and high-temperature radiation of boiler flue gas, is made of high heat-resistant and corrosion-resistant alloy plate, preferably 06Cr25Ni20 (310S) austenitic heat-resistant stainless steel or Cr25Ni35Nb heat-resistant alloy steel plate, with a plate thickness of 6mm-10mm; 310S is suitable for areas with boiler flue gas temperatures ≤1000℃, and Cr25Ni35Nb is suitable for high-temperature areas with boiler flue gas temperatures ≤1200℃. This material has excellent high-temperature oxidation resistance, thermal shock resistance, and wear resistance. Under long-term high-temperature operating conditions of the boiler (≤1200℃), there is no obvious oxidation, peeling, or deformation, which can effectively resist the scouring and corrosion of high-temperature flue gas; at the same time, the material has good toughness and can be formed into structures such as flanges and positioning steps through stamping and bending, which facilitates quick alignment and assembly with the intermediate plate; in addition, the material has excellent machinability, and holes can be directly drilled on the plate to form the sealing rod in one piece, meeting the structural processing requirements.

[0047] All of the above materials are selected to match the actual service conditions of the boiler wall panels. They can be flexibly adjusted according to the temperature and flue gas corrosivity differences in different parts of the boiler. All materials are commonly used industrial standard plates / sealants, which are easy to purchase and process, and meet the requirements of on-site construction and large-scale production.

[0048] The implementation principle of the composite structure for preventing cracking and smoke leakage in boiler wall panels in Embodiment 1 of this application is as follows: through the synergistic effect of "three-layer composite + mechanical anchoring + elastic sealing", all-round repair and long-term protection of cracks are achieved. During construction, the plug-in seat 5 on the intermediate plate 2 is first inserted into the crack of the old wall panel. In the initial state, the elastic ring 17 (first ring body 21) abuts against the mating block 16 on the connecting plate 15, and the support rod 9 is gathered into the receiving groove 10 to ensure that the plug-in seat 5 is smoothly positioned. After positioning, the first ring body 21 is pulled to release the constraint on the mating block 16. The elastic part (spring 11) in the receiving groove 10 releases the elastic potential energy, pushes the connecting plate 15 to drive all the support rods 9 to extend synchronously along the receiving groove 10. The pointed conical end of the support rod 9 penetrates the side wall of the crack, squeezing out the loose wall material on the side wall, which not only achieves the stable anchoring of the support rod 9, but also creates a clean and solid interface for the sealant bonding. Subsequently, sealant is injected through injection channel 7. The sealant is diverted through injection chamber 12 and overflows from each outlet hole 6, filling all gaps between the crack, the plug-in seat 5, and the crack sidewall. Simultaneously, it flows into the mounting hole 13, wrapping the spring 11 and solidifying with the support rod 9 and the wall of the mounting hole 13. This protects the spring 11 from high-temperature flue gas corrosion and upgrades the elastic anchoring of the support rod 9 to rigid locking. The layered connection between the protective plate 1, the intermediate plate 2, and the old wall panel extends the flue gas leakage path. The intermediate plate 2 acts as a stress buffer, preventing the force on the protective plate 1 from being directly transmitted to the crack and causing secondary cracking. The protective plate 1 can be disassembled and replaced separately, reducing maintenance costs. Finally, the anchoring of the support rod 9, the bonding of the sealant, and the pre-tightening of the elastic ring 17 work together to form a stable composite protective structure, effectively preventing the expansion of cracks in the furnace wall panel and flue gas leakage, adapting to the harsh operating conditions of the boiler with high temperature and vibration. Example 2

[0049] The difference between Example 2 and Example 1 is that: (Refer to...) Figure 8 The first adhesive hole 23 is opened at the joint position of the plug-in seat 5 and the intermediate plate 2. The first adhesive hole 23 is set outward along the direction towards the crack of the old wall panel. The first adhesive hole 23 includes a first part 26 located on the plug-in seat 5 and a second part 27 located on the intermediate plate 2. When the plug-in seat 5 is in place, the first ring body 21 is pulled outward, so that the first ring body 21 releases the constraint on the mating block 16. The first ring body 21 is pulled to the position that covers the first part 26.

[0050] The implementation principle of Example 2 is as follows: the sealant flowing out through the first glue hole 23 can flow more concentratedly to the plug socket 5, the crack opening position on the old wall panel and the position of the middle plate 2, thereby strengthening the tightness of the connection at this position. Example 3

[0051] The difference between Example 3 and Example 1 is that: (Refer to...) Figures 9-10The outer sidewall of the elastic ring 17 is provided with at least one annular groove 18 along the circumferential direction (in embodiment 3 of this application, the cross-sectional shape of the annular groove 18 is trapezoidal; in other embodiments, the cross-sectional shape of the annular groove 18 may also be dovetail-shaped or other shapes). The sidewall of the elastic ring 17 is uniformly distributed with a plurality of axial guide grooves 19 along the circumferential direction. Each axial guide groove 19 passes through all the annular grooves 18 along the axial direction of the elastic ring 17 and forms a connection. The axial guide grooves 19 are provided in a one-to-one correspondence with the glue outlet holes 6 facing the inner wall of the elastic ring 17, so that the sealant flows into the axial guide grooves 19 through the glue outlet holes 6 and then quickly flows into each annular groove 18 to form an interlocking structure.

[0052] The implementation principle of Example 3 is as follows: By opening an interconnected annular groove 18 and axial guide groove 19 on the outer wall of the elastic ring 17, the bonding strength between the elastic ring 17 and the sealant is further enhanced. During the injection process, after the sealant flows out through the outlet hole 6 facing the inner wall of the elastic ring 17, it will preferentially enter the axial guide groove 19 and spread rapidly and evenly along the axial direction of the elastic ring 17 under the guidance effect, while flowing smoothly into the circumferentially arranged annular groove 18. After the sealant is filled and cured in the groove, it will form a mechanical interlocking structure that interlocks with the elastic ring 17, so that the sealant no longer relies solely on surface adhesion to bond with the elastic ring 17, effectively avoiding the problem of peeling and debonding between the sealant and the elastic ring 17 under high temperature conditions. At the same time, after the elastic ring 17 expands due to heat, it adheres tightly to the side wall of the crack and the outer wall of the plug seat 5. Together with the sealant cured in the annular groove 18, it forms a dual reinforcement structure of "thermal expansion mechanical locking + adhesive layer interlocking and bonding". This can not only prevent the gap rebound caused by the aging and shrinkage of the sealant, but also further extend the flue gas leakage path, greatly improving the stability and reliability of the composite structure in preventing cracking and smoke leakage under long-term high temperature and vibration conditions. Example 4

[0053] This application embodiment 4 discloses a construction process for a composite structure for preventing cracking and smoke leakage in boiler wall panels, used for the construction of a composite structure for preventing cracking and smoke leakage in boiler wall panels as described in embodiment 1, including the following steps; S1. On-site preparation and positioning: Determine the area to be repaired and clean the surface dust and loose oxide scale from the cracks; Align the intermediate plate 2 and the plug-in socket 5 set on it with the crack; S2. Preliminary anchoring and sealing: Insert the connector 5 smoothly into the crack in the old wall panel along the direction of the crack; The intermediate plate 2 is initially connected to the old wall panel by the first screw 301, the intermediate plate 2 is fixedly connected to the old wall panel, and there is a certain gap between the intermediate plate 2 and the old wall panel. Pull the elastic ring 17 that abuts against the mating block 16, and the mating block 16 is released from constraint. The strut 9 slides radially along the plug seat 5 until it abuts against the periphery of the crack on the old wall panel. The elastic ring 17 that abuts against the mating block 16 blocks the corresponding part of the glue outlet 6. S3. Interface Preprocessing and Enhancement: Insert the glue injection tube into the crack of the old wall panel through the glue injection channel 7, and introduce dry compressed air or nitrogen into the glue injection tube to thoroughly blow away the inner wall of the crack and remove residual impurities and moisture. After the purging is completed, the intermediate plate 2 is further connected to the old wall panel by the first screw 301, so that the intermediate plate 2 and the old wall panel are tightly attached. The sealant, which has a certain temperature, is injected through the injection tube. During the injection process, the injection tube is slowly pulled outward. The sealant first flows out through the opening at the end of the connector 5 to the depth of the crack in the old wall panel. During the slow pulling out of the injection tube, the sealant flows out through each of the injection holes 6 (including the first injection hole 23 and the second injection hole 24). The heat of the injected high-temperature sealant is transferred to the elastic ring 17 (including the main ring body 171 and each of the branches 172 thereon), causing it to expand due to heat. The sealant fills the gap between the crack and the plug seat 5 and the side wall of the crack. Inject sealant into the chamfered area that communicates with the first connecting hole 25; S4. Curing and Assembly: Monitor the state of the sealant. When the sealant's fluidity decreases to a preset state, insert the sealing rod 801 into the sealant injection channel 7. The protective plate 1 and the intermediate plate 2 are tightly fitted together. Connect the protective plate 1 and the intermediate plate 2 with the second screw 401 to complete the installation of the composite structure.

[0054] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A composite structure for preventing cracking and smoke leakage in boiler furnace wall panels, characterized in that: The application relates to a protective plate (1) and an intermediate plate (2); the intermediate plate (2) is used for covering a crack area of an old wall plate, the intermediate plate (2) is arranged between the old wall plate and the protective plate (1), and one side of the intermediate plate (2) is provided with a crack joint part used for being combined with a crack on the old wall plate; one side of the intermediate plate (2) is connected with the old wall plate through a first connecting piece (3), and the other side is connected with the protective plate (1) through a second connecting piece (4).

2. A composite structure for preventing cracking and smoke leakage of a boiler wall panel according to claim 1, wherein: The crack joint part comprises a plug-in seat (5) used for being inserted into the crack on the old wall plate, the plug-in seat (5) is arranged on one side of the intermediate plate (2) facing the old wall plate, a plurality of glue outlet holes (6) are arranged on the plug-in seat (5) in a circumferential direction, an injection glue channel (7) is arranged on the intermediate plate (2) and communicates with the glue outlet holes (6), and a blocking piece (8) is arranged on the protective plate (1) and used for blocking the injection glue channel (7).

3. A composite structure for preventing cracking and smoke leakage of a boiler wall panel according to claim 2, wherein: A plurality of supporting rods (9) are movably arranged on the plug-in seat (5), a driving piece is arranged on the plug-in seat (5) and used for driving the supporting rods (9) to move in a direction close to a side wall of the crack on the old wall plate, and one end of the supporting rod (9) close to the crack on the old wall plate is in a pointed cone shape.

4. The composite structure for preventing cracking and smoke leakage of a boiler wall panel according to claim 3, wherein: A plurality of accommodating grooves (10) are arranged on the plug-in seat (5), one supporting rod (9) is slidingly matched in each accommodating groove (10), the driving piece comprises an elastic part arranged in the accommodating groove (10), one end of the elastic part is fixedly connected in the accommodating groove (10), and the other end abuts against one end of the supporting rod (9) away from the crack on the old wall plate.

5. The composite structure of a boiler wall panel for preventing cracking and smoke leakage according to claim 4, wherein: An injection glue cavity (12) is arranged in the plug-in seat (5), the injection glue channel (7) and the glue outlet holes (6) communicate with the injection glue cavity (12), a mounting hole (13) is arranged in the groove bottom of the accommodating groove (10), the mounting hole (13) communicates with the injection glue cavity (12), the elastic part comprises a spring (11) arranged in the mounting hole (13), one end of the spring (11) is fixedly connected in the mounting hole (13), and the other end abuts against one end of the supporting rod (9) away from the crack on the old wall plate.

6. The composite structure for preventing cracking and smoke leakage of a boiler wall panel according to claim 4, wherein: A connecting plate (15) is slidingly arranged in the accommodating groove (10), the supporting rod (9) is connected with the elastic part through the connecting plate (15), one side of the connecting plate (15) is connected with the supporting rod (9), and the other side abuts against the other end of the elastic part; a matching block (16) is arranged on the connecting plate (15), the matching block (16) and the supporting rod (9) are arranged on the same side of the connecting plate (15), an elastic ring (17) is arranged on the plug-in seat (5), and an inner wall of the elastic ring (17) abuts against the matching block (16).

7. The composite structure of a boiler wall panel to prevent cracking and smoke leakage according to claim 6, wherein: The elastic ring (17) is made of a material with thermal expansion performance, and the outlets of part of the glue outlet holes (6) are arranged towards the inner wall of the elastic ring (17).

8. The composite structure of claim 7, wherein: The elastic ring (17) comprises a main ring body (171) sleeved on the socket (5) and a plurality of branch petals (172), the outlets of part of the glue outlets (6) are arranged towards the inner wall of the main ring body (171), the main ring body (171) and the plurality of branch petals (172) are both made of a material with thermal expansion performance, the plurality of branch petals (172) are arranged on the outer wall of the main ring body (171) in a circumferential direction, and the branch petals (172) extend and are arranged in an inclined manner away from the socket (5).

9. The composite structure of claim 7, wherein: The outer wall of the elastic ring (17) is provided with an annular clamping groove (18) and an axial flow guide groove (19) in a circumferential direction, and the annular clamping groove (18) and the axial flow guide groove (19) are in communication with each other.

10. A construction process of a composite structure for preventing cracking and smoke leakage of a boiler wall panel, for constructing the composite structure for preventing cracking and smoke leakage of a boiler wall panel according to any one of claims 2 to 9, characterized by: The method comprises the following steps: S1, on-site preparation and positioning: determining the range to be repaired, aligning the intermediate plate (2) and the socket (5) arranged thereon with the crack; S2, preliminary anchoring and sealing: inserting the socket (5) into the crack of the old wall plate; S3, interface pretreatment and enhancement: introducing high-pressure gas into the socket (5) through the glue injection channel (7) to clean the inner wall of the crack; Then, sealant is injected into the glue injection channel (7), and the sealant flows out through the glue outlet (6) to fill the crack and the gap between the socket (5) and the crack wall; S4, curing and assembly: after the flowability of the sealant is reduced, the intermediate plate (2) is tightly connected with the old wall plate through the first connecting piece (3), and then the protective plate (1) is connected with the intermediate plate (2) through the second connecting piece (4), the glue injection channel (7) is tightly blocked by the blocking piece (8), and the installation of the composite structure is completed.

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