A duct structure for building ventilation

Abstract

The application discloses a duct structure for building ventilation, and relates to the technical field of the duct, which comprises a plurality of duct bodies and a plurality of bearing frames, a first connecting frame plate is fixedly installed at one end of the duct body, a second connecting frame plate is fixedly installed at the other end of the duct body, a plug-in assembly is arranged on the first connecting frame plate, and a limiting assembly is arranged on the second connecting frame plate. The plug-in assembly is inserted into the limiting assembly in cooperation with the limiting assembly, the connection of bolts and nuts in the external environment is not needed, even in a narrow space, an operator can conveniently perform construction, the height of the duct can be adjusted through the lifting assembly, the butt joint of the duct is facilitated, the duct is suitable for installation at various heights, and the duct is stably supported through the damping assembly, and vibration generated during the work of the duct is prevented.

Description

Technical Field

[0001] This invention relates to the technical field of air ducts, specifically to an air duct structure for building ventilation. Background Technology

[0002] In building ventilation systems, ducts, as the core component for air transport and circulation, have a profound impact on indoor environmental quality and energy efficiency. With the diversification of building functions and increasingly stringent energy-saving requirements, traditional duct structures are gradually revealing many problems that urgently need to be addressed:

[0003] Traditional air ducts mostly use flange bolt connections. In large-scale building ventilation projects, duct installation involves a large amount of bolt tightening work, which is cumbersome, time-consuming, and results in high labor costs. Furthermore, bolt connections are susceptible to defects caused by the precision of the installers, easily leading to incomplete seals and air leaks. This reduces ventilation efficiency and increases fan energy consumption. In commercial complex ventilation systems, for example, air leaks in the ducts force the fans to perform extra work to compensate for the airflow, resulting in unnecessary energy waste and contradicting the goal of efficient ventilation and energy conservation.

[0004] When a ventilation system is running, the vibration of the fan and the impact of airflow cause vibration in the ductwork, which is then transmitted. Traditional ducts lack effective vibration damping and buffering designs, and this vibration is transmitted to the building structure, causing secondary noise and interfering with the indoor acoustic environment. In residential and office buildings, where acoustic requirements are high, if the noise from duct vibration exceeds environmental noise standards, it will affect the comfort and work efficiency of personnel. It will also accelerate the aging of ducts and connecting components, shorten the system's lifespan, and make it difficult to meet the requirements of stability and quietness for ventilation systems.

[0005] Different architectural spaces, such as commercial buildings with varying floor heights and laboratories with specific ventilation needs, have different requirements for duct installation height and airflow guidance. Traditional ducts have a fixed height, making it difficult to flexibly adapt to complex architectural layouts; moreover, their function is singular, merely serving as airflow channels, unable to dynamically adjust air volume and speed according to actual spatial needs, thus failing to achieve intelligent control. In the current climate of vigorous promotion of green and smart buildings, traditional ducts struggle to align with the trend of ventilation systems moving towards energy conservation, intelligence, and high adaptability, limiting the overall efficiency improvement of building ventilation systems. Summary of the Invention

[0006] To address the problems of inefficient connections, poor vibration and noise reduction, and weak spatial adaptability and functional expansion in existing building ventilation ducts, it is necessary to innovate duct structure design, optimize connection methods, enhance vibration reduction performance, and improve spatial adaptability and functional control capabilities, so as to promote the development of building ventilation systems towards high efficiency, energy saving, and intelligence. This paper provides a duct structure for building ventilation.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a duct structure for building ventilation, comprising several duct bodies and several load-bearing frames, wherein a first connecting frame plate is fixedly installed at one end of each duct body, and a second connecting frame plate is fixedly installed at the other end of each duct body; an insertion assembly is provided on the first connecting frame plate, a limiting assembly is provided on the second connecting frame plate, a shock-absorbing assembly is provided within the load-bearing frames, the duct body is located within the load-bearing frames, the shock-absorbing assembly is connected to the duct body, and a lifting assembly is provided on the load-bearing frames.

[0008] Preferably, the insertion assembly includes a plurality of cylindrical columns, a plurality of first mounting holes are provided on the first connecting frame plate, the cylindrical columns are fixedly installed in the first mounting holes, a threaded column is rotatably installed between the two inner walls of the cylindrical column, one end of the threaded column is exposed outside the cylindrical column, a first inner cavity is provided on the upper and lower inner walls of the cylindrical column respectively, a first through hole is provided on the lower wall of the first inner cavity, a second through hole is provided on the upper wall of the first inner cavity, a first limiting plate is slidably installed in the first inner cavity, a top block is fixedly installed on the lower wall of the first limiting plate, the top block passes through the first through hole, a limiting block is fixedly installed on the upper wall of the first limiting plate, the limiting block passes through the second through hole, a first spring is fixedly installed between the first limiting plate and the upper wall of the first inner cavity, the first spring is sleeved on the limiting block, a pushing block is engaged with the threaded column, and an annular groove is provided on the outer wall of the cylindrical column.

[0009] Preferably, the end of the pushing block near the top block has a frustum structure, and the end of the top block inside the cylinder has a trapezoidal structure.

[0010] Preferably, the upper and lower walls of the cylinder are provided with sliding grooves on one side of the first inner cavity, and a slider is slidably installed in the sliding groove, and the push block is fixedly installed between the sliders.

[0011] Preferably, the limiting component includes a cylindrical body, a plurality of second mounting holes are provided on the second connecting frame plate, the cylindrical body is fixedly installed in the second mounting holes, the side wall of the cylindrical body has an open structure, the inner diameter of the cylindrical body near the open end is smaller than the inner diameter near the closed end, a second inner cavity is provided on the inner wall of the cylindrical body near the open end, a first through hole is provided on the lower wall of the second inner cavity, a second through hole is provided on the upper wall of the second inner cavity, a second limiting plate is slidably installed in the second inner cavity, a blocking rod is fixedly installed on the lower wall of the second limiting plate, the lower end of the blocking rod passes through the first through hole, a second spring is fixedly installed between the lower wall of the second limiting plate and the lower wall of the second inner cavity, the second spring is fitted on the blocking rod, a ball is movably installed on the upper wall of the second limiting plate, the ball passes through the second through hole, an external thread is provided on the outer wall of the cylindrical body, and a first internal threaded sleeve is connected to the cylindrical body through the outer wall, the inner wall section of the first internal threaded sleeve near the second connecting frame plate has an inclined structure.

[0012] Preferably, the shock absorption component includes a slide rail, which is fixedly installed on the four walls inside the load-bearing frame. A pair of movable blocks are slidably installed inside the slide rail. A third spring is fixedly installed between the movable blocks and the slide rail. A connecting rod is hinged to the movable block, and the other end of the connecting rod is hinged to the outer wall of the duct body.

[0013] Preferably, the lifting assembly includes a pair of lifting cylinders, the lower end of which has an open structure. A second internally threaded sleeve is rotatably installed at the lower end of the lifting cylinder, and a lead screw is screwed into the second internally threaded sleeve. Guide grooves are respectively opened on the inner side walls of the lifting cylinders, and guide blocks are slidably installed in the guide grooves. The upper end of the lead screw is fixedly installed between the guide blocks. A driven gear is fixedly installed on the outer wall of the second internally threaded sleeve. A housing is fixedly installed between the lifting cylinders, and the second internally threaded sleeve is located inside the housing. A pair of support plates are fixedly installed inside the housing, and a rotating rod is rotatably installed between the pair of support plates. A driving gear is fixedly installed at both ends of the rotating rod, and the driving gear meshes with the driven gear. A handwheel is fixedly installed on the rotating rod and located between the pair of support plates. The handwheel passes through the upper and lower walls of the housing. The lower end of the lead screw is fixedly installed on the side wall of the bearing frame through a threaded block.

[0014] Preferably, both the driving gear and the driven gear are bevel gear structures.

[0015] Preferably, some of the duct bodies are one or a combination of square tubes or arc tubes.

[0016] Beneficial Effects: This invention provides a duct structure for building ventilation, solving the technical problem that existing ductwork requires bolts and nuts for connection, which is inconvenient in narrow spaces and difficult for workers to install, thus reducing the ease of connection. This invention uses a combination of insert and limiting components, allowing the insert to be inserted into the limiting component without external bolts and nuts. This facilitates installation even in confined spaces. The lifting component adjusts the height of the ductwork, facilitating connection and making the ductwork suitable for installation at various heights. The shock-absorbing component provides stable support for the ductwork, preventing vibrations during operation. In summary, this invention has the following advantages:

[0017] 1. The insertion assembly of the first connecting frame plate cooperates with the limiting assembly of the second connecting frame plate. The rotating threaded column drives the pushing block to press against the top block, causing the limiting block to engage with the stepped inner wall of the cylinder. At the same time, tightening the first internal threaded sleeve pushes the rolling ball down to press against the blocking rod, achieving bidirectional locking. This eliminates the need for traditional bolts and nuts, allowing connection to be completed simply by rotation. This avoids the inconvenience of bolt installation in confined spaces, significantly improving construction efficiency. It is especially suitable for engineering scenarios with limited space. The frustum structure of the pushing block and the trapezoidal structure of the top block cooperate to form a wedge-shaped transmission, amplifying the locking force. The sliding contact design between the rolling ball and the inclined inner wall reduces frictional resistance, making the locking process smoother. Meanwhile, the snap-fit ​​structure between the annular groove and the blocking rod prevents the duct from axially disengaging, ensuring connection stability.

[0018] 2. The lifting assembly is driven by a handwheel-driven rotating rod, which, through the drive gear and driven gear, drives the second internal threaded sleeves on both sides to rotate synchronously. This drives the lead screw to move up and down along the guide groove, thereby adjusting the height of the supporting frame and the main body of the duct. A single person can complete the height alignment of multiple duct sections without the need for complex hoisting equipment. It is suitable for building structures with different floor heights, and is especially convenient for duct installation in multi-story buildings or irregularly shaped spaces. The cooperation between the guide groove and the guide block limits the radial displacement of the lead screw, ensuring a smooth and wobbly lifting process.

[0019] 3. The vibration damping system consists of slide rails, moving blocks, third springs, and connecting rods within the load-bearing frame: When the duct vibrates, the connecting rods push the moving blocks to compress the third springs. The spring deformation absorbs the vibration energy, reducing the transmission of vibration to the building structure. This effectively reduces noise and swaying during duct operation, extends the service life of the duct and connectors, and improves the comfort of the building environment, meeting the high requirements of the project for equipment stability. The slide rails are installed on the four walls of the load-bearing frame and can absorb vibrations in both horizontal and vertical directions. The hinged structure of the connecting rods allows the duct to swing slightly, adapting to deformation caused by thermal expansion and contraction, and avoiding structural damage caused by rigid connections.

[0020] 4. The main body of the duct can be square, curved or a combination thereof, which can flexibly adapt to different ventilation paths (such as right-angle turns, curved bends, etc.), reduce airflow resistance and improve ventilation efficiency. Each component (such as insert components, limit components, lifting cylinders, etc.) is an independent module that can be disassembled and replaced individually, reducing maintenance costs. The open structure of the load-bearing frame facilitates later inspection and cleaning.

[0021] In summary, this invention overcomes the technical bottlenecks of traditional ducts in terms of construction convenience, installation adaptability, and operational stability through three core innovations: boltless quick connection, height adaptive adjustment, and multi-dimensional shock absorption support. It is especially suitable for scenarios with stringent ventilation requirements, such as high-rise buildings and underground spaces, and has the dual value of improving engineering efficiency and optimizing safety performance. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the main structure of the present invention.

[0023] Figure 2 This is a bottom-view structural diagram of the present invention.

[0024] Figure 3 This is a schematic diagram of the assembly structure of the plug-in component and the limiting component of the present invention.

[0025] Figure 4 This is a rear view schematic diagram of the plug-in assembly and the limiting assembly of the present invention.

[0026] Figure 5 This is a cross-sectional view of the insertion component and the limiting component of the present invention.

[0027] Figure 6 This is a cross-sectional view of the lifting assembly and shock absorption assembly of the present invention.

[0028] Figure 7 for Figure 6 A schematic diagram of a local structure in the image;

[0029] Figure 8 for Figure 5 Enlarged view of point A in the image.

[0030] In the diagram: 1. Main body of the duct; 2. Support frame; 3. First connecting frame plate; 4. Second connecting frame plate; 5. Cylinder column; 6. Threaded column; 7. First limiting plate; 8. Top block; 9. Limiting block; 10. First spring; 11. Pushing block; 12. Annular groove; 13. Slide groove; 14. Sliding block; 15. Cylinder body; 16. Second limiting plate; 17. Blocking rod; 18. Second spring; 19. Ball bearing; 20. External thread; 21. First internal thread sleeve; 22. Slide rail; 23. Moving block; 24. Third spring; 25. Connecting rod; 26. Lifting cylinder; 27. Second internal thread sleeve; 28. Lead screw; 29. ​​Guide groove; 30. Guide block; 31. Driven gear; 32. Box body; 33. Support plate; 34. Rotating rod; 35. Driving gear; 36. Handwheel. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Please see Figures 1-8 This invention provides a technical solution: a duct structure for building ventilation, comprising several duct bodies 1 and several load-bearing frames 2. A first connecting frame plate 3 is fixedly installed at one end of the duct body 1, and a second connecting frame plate 4 is fixedly installed at the other end of the duct body 1. The first connecting frame plate 3 is provided with an insertion component, and the second connecting frame plate 4 is provided with a limiting component. A shock-absorbing component is provided inside the load-bearing frame 2. The duct body 1 is located inside the load-bearing frame 2, and the shock-absorbing component is connected to the duct body 1. A lifting component is provided on the load-bearing frame 2. Through the cooperation of the insertion component and the limiting component, the insertion component is inserted into the limiting component, eliminating the need for external bolts and nuts. This facilitates construction even in confined spaces. The height of the duct body 1 can be adjusted through the lifting component, facilitating the docking of the duct body 1 and making the duct body 1 suitable for installation at various heights. The shock-absorbing component provides stable support for the duct body 1, preventing vibrations generated during operation.

[0033] In this embodiment, the insertion assembly includes several cylindrical columns 5. A first connecting frame plate 3 has several first mounting holes. The cylindrical columns 5 are fixedly installed in the first mounting holes. A threaded column 6 is rotatably installed between the two inner walls of the cylindrical column 5, with one end of the threaded column 6 protruding from the cylindrical column 5. First inner cavities are respectively formed on the upper and lower inner walls of the cylindrical column 5. A first through hole is formed on the lower wall of the first inner cavity, and a second through hole is formed on the upper wall of the first inner cavity. A first limiting plate 7 is slidably installed in the first inner cavity. A top block 8 is fixedly installed on the lower wall of the first limiting plate 7, and the top block 8 passes through the first through hole. The first limiting plate 7... A limiting block 9 is fixedly installed on the wall, and the limiting block 9 passes through the second through hole. A first spring 10 is fixedly installed between the first limiting plate 7 and the upper wall of the first inner cavity. The first spring 10 is fitted onto the limiting block 9. A push block 11 is engaged with the threaded column 6. An annular groove 12 is opened on the outer wall of the cylinder 5. The end of the push block 11 near the top block 8 has a frustum structure. The end of the top block 8 located inside the cylinder 15 has a trapezoidal structure. A sliding groove 13 is opened on the upper and lower walls of the cylinder 5 and on one side of the first inner cavity. A slider 14 is slidably installed in the sliding groove 13. The push block 11 is fixedly installed between the sliders 14.

[0034] When it is necessary to connect the main body 1 of the air duct, insert the cylinder 5 into the corresponding cylinder 15, rotate the threaded column 6, and push the block 11 to move along the slide groove 13 under the drive of the threaded column 6; since the frustum structure of the push block 11 cooperates with the trapezoidal structure of the top block 8, the movement of the push block 11 will push the top block 8 to move upward, thereby driving the limiting block 9 to extend out from the second through hole and lock into the stepped inner wall of the cylinder 15 to achieve initial locking.

[0035] In this embodiment, the limiting component includes a cylindrical body 15. A plurality of second mounting holes are provided on the second connecting frame plate 4. The cylindrical body 15 is fixedly installed within the second mounting holes. The sidewall of the cylindrical body 15 has an open structure. The inner diameter of the cylindrical body 15 near the open end is smaller than the inner diameter near the closed end. A second inner cavity is provided on the inner wall surface near the open end of the cylindrical body 15. A first through hole is provided on the lower wall surface of the second inner cavity, and a second through hole is provided on the upper wall surface of the second inner cavity. A second limiting plate 16 is slidably installed within the second inner cavity. The lower wall surface of the second limiting plate 16... A blocking rod 17 is fixedly installed, with its lower end passing through the first through hole. A second spring 18 is fixedly installed between the lower wall of the second limiting plate 16 and the lower wall of the second inner cavity. The second spring 18 is fitted onto the blocking rod 17. A ball bearing 19 is movably installed on the upper wall of the second limiting plate 16, passing through the second through hole. An external thread 20 is provided on the outer wall of the cylinder 15. A first internal thread sleeve 21 is connected to the outer wall of the cylinder 15. The inner wall section of the first internal thread sleeve 21 near the end of the second connecting frame plate 4 has an inclined structure.

[0036] When it is necessary to adjust the height of the duct body 1, turn the handwheel 36. The handwheel 36 drives the rotating rod 34 to rotate. The driving gear 26 on the rotating rod 34 drives the driven gear 27 to rotate, thereby driving the second internal threaded sleeve 27 to rotate. The rotation of the second internal threaded sleeve 27 causes the lead screw 28 to move up and down along the lifting cylinder 26, thereby adjusting the height of the bearing frame 2 and thus adjusting the height of the duct body 1 to adapt to different installation environments.

[0037] In this embodiment, the shock absorption component includes a slide rail 22, which is fixedly installed on the four walls inside the bearing frame 2. A pair of moving blocks 23 are slidably installed inside the slide rail 22. A third spring 24 is fixedly installed between the moving blocks 23 and the slide rail 22. A connecting rod 25 is hinged to the moving blocks 23, and the other end of the connecting rod 25 is hinged to the outer wall of the duct body 1.

[0038] When the duct body 1 is subjected to vibration, the vibration is transmitted to the moving block 23 through the connecting rod 25. The moving block 23 slides in the slide rail 22 and compresses the third spring 24. The elastic deformation of the third spring 24 absorbs the vibration energy, reduces the impact of vibration on the duct body 1 and the load-bearing frame 2, and improves the stability and service life of the system.

[0039] In this embodiment, the lifting assembly includes a pair of lifting cylinders 26. The lower end of each lifting cylinder 26 has an open structure. A second internally threaded sleeve 27 is rotatably mounted on the lower end of each lifting cylinder 26. A lead screw 28 is screwed into the second internally threaded sleeve 27. Guide grooves 29 are respectively provided on the inner side walls of the lifting cylinders 26. Guide blocks 30 are slidably mounted in the guide grooves 29. The upper end of the lead screw 28 is fixedly mounted between the guide blocks 30. A driven gear 31 is fixedly mounted on the outer wall of the second internally threaded sleeve 27. A housing 32 is fixedly mounted between the lifting cylinders 26, and the second internally threaded sleeve 27 is located inside the housing 32. A pair of support plates 33 are fixedly installed inside the box body 32. A rotating rod 34 is rotatably installed between the pair of support plates 33. A drive gear 35 is fixedly installed at both ends of the rotating rod 34. The drive gear 35 is meshed with the driven gear 31. Both the drive gear 35 and the driven gear 31 are bevel gear structures. A handwheel 36 is fixedly installed on the rotating rod 34 between the pair of support plates 33. The handwheel 36 passes through the upper and lower walls of the box body. The lower end of the lead screw 28 is fixedly installed on the side wall of the bearing frame 2 through a threaded block. The lead screw 28 can rotate within the threaded block, thereby driving the bearing frame 2 to move.

[0040] When it is necessary to adjust the height of the duct body 1, turn the handwheel 36 to drive the rotating rod 34 and the two end drive gears 35 to rotate synchronously. The drive gear 35 drives the driven gear 31 and the second internal thread sleeve 27 to rotate. Since the lead screw 28 cannot rotate due to the restriction of the guide block 30, the rotation of the second internal thread sleeve 27 will be converted into the vertical lifting motion of the lead screw 28, thereby driving the bearing frame 2 to move up and down along the lifting cylinder 26 to realize the height adjustment of the duct body 1.

[0041] In this embodiment, the main body 1 of several ducts is one or a combination of two of the following: square tubes or arc-shaped tubes. The main body 1 of the duct can be square tubes, arc-shaped tubes or combinations thereof, which can flexibly adapt to different ventilation paths (such as right-angle turns, arc bends, etc.), reduce airflow resistance and improve ventilation efficiency.

[0042] Its detailed connection method is a well-known technology in this field. The following mainly introduces the working principle and process, and the specific work is as follows.

[0043] Example: As shown in the accompanying drawings, during use, the lifting cylinder 26 is fixedly installed on the wall of the hanging duct body 1. When the handwheel 36 is turned, it drives the rotating rod 34 to rotate, which in turn drives the driving gear 35 to rotate. Since the driving gear 35 meshes with the driven gear 31, the driven gear 31 rotates, which in turn drives the second internal threaded sleeve 27 to rotate. Since the second internal threaded sleeve 27 meshes with the lead screw 28, its rotation drives the lead screw. The lead screw 28 moves along the guide groove 29 under the action of the guide block 30, thereby adjusting the height of the duct body 1 so that all parts of the duct body 1 are at a uniform height. Then, the cylinder column 5 is inserted into the cylinder body 15, and the first internal threaded sleeve 21 is rotated. The first internal threaded sleeve 21 moves along the outer... The movement of the thread 20 causes the first internal thread sleeve 21 to push the ball 19 during its movement. The ball 19 pushes the second limiting plate 16 to compress the second spring 18. The second limiting plate 16 pushes the blocking rod 17 to insert into the annular groove 12, thereby limiting the cylinder 5. The threaded column 6 is rotated. Since the threaded column 6 is engaged with the pushing block 11, the threaded column 6 has a driving effect on the pushing block 11. The pushing block 11 moves along the path of the sliding groove 13 under the action of the slider 14, thereby pushing the top block 8. The top block 8 pushes the first limiting plate 7. The first limiting plate 7 squeezes the first spring 10. The first limiting plate 7 pushes the limiting block 9, so that the inner diameter of the limiting block 9 near the open end of the cylinder 15 is smaller than the inner diameter near the closed end, thereby making the limiting block 9 snap into the cylinder 5, thereby connecting the two sections of the air duct body 1.

[0044] When the duct body 1 is vibrated, the duct body 1 pushes the connecting rod 25, which in turn pushes the moving block 23. The moving block 23 moves along the path of the slide rail 22, and the moving block 23 compresses the third spring 24. The third spring 24 deforms and thus plays a role in shock absorption.

[0045] The duct structure for building ventilation provided by this invention enables quick connection without bolts and nuts through the cooperation of insert components and limiting components, facilitating construction in confined spaces; the duct height can be adjusted with the help of lifting components to adapt to different installation height requirements; and the vibration damping components provide stable support for the duct, reducing vibration during operation. Thus, it has significant effects in improving installation convenience, enhancing structural adaptability, and ensuring system stability, and can effectively optimize the performance of building ventilation ducts.

[0046] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

Claims

1. A duct structure for building ventilation, comprising several duct bodies (1) and several load-bearing frames (2), characterized in that, The air duct body (1) is fixedly installed with a first connecting frame plate (3) at one end and a second connecting frame plate (4) is fixedly installed at the other end. The first connecting frame plate (3) is provided with an insertion component and the second connecting frame plate (4) is provided with a limiting component. The bearing frame (2) is provided with a shock-absorbing component. The air duct body (1) is located inside the bearing frame (2). The shock-absorbing component is connected to the air duct body (1). The bearing frame (2) is provided with a lifting component. The insertion assembly includes several cylindrical columns (5). Several first mounting holes are provided on the first connecting frame plate (3). The cylindrical columns (5) are fixedly installed in the first mounting holes. Threaded columns (6) are rotatably installed between the two inner walls of the cylindrical columns (5). One end of the threaded column (6) is exposed outside the cylindrical column (5). First inner cavities are respectively provided on the upper and lower inner walls of the cylindrical columns (5). A first through hole is provided on the lower wall of the first inner cavity. A second through hole is provided on the upper wall of the first inner cavity. A first limiting plate (7) is slidably installed in the first inner cavity. A top block (8) is fixedly installed on the lower wall of the first limiting plate (7), the top block (8) passes through the first through hole, a limiting block (9) is fixedly installed on the upper wall of the first limiting plate (7), the limiting block (9) passes through the second through hole, a first spring (10) is fixedly installed between the first limiting plate (7) and the upper wall of the first inner cavity, the first spring (10) is fitted on the limiting block (9), a push block (11) is engaged with the threaded column (6), and an annular groove (12) is opened on the outer wall of the cylindrical column (5). The push block (11) has a frustum structure at one end near the top block (8), and the top block (8) has a trapezoidal structure at one end inside the cylinder (15). The inner upper and lower walls of the cylindrical column (5) and one side of the first inner cavity are provided with a sliding groove (13), and a slider (14) is slidably installed in the sliding groove (13). The push block (11) is fixedly installed between the sliders (14). The limiting component includes a cylindrical body (15), and a plurality of second mounting holes are provided on the second connecting frame plate (4). The cylindrical body (15) is fixedly installed in the second mounting holes. The side wall of the cylindrical body (15) has an open structure. The inner diameter of the cylindrical body (15) near the open end is smaller than the inner diameter near the closed end. A second inner cavity is provided on the inner wall of the cylindrical body (15) near the open end. A first through hole is provided on the lower wall of the second inner cavity. A second through hole is provided on the upper wall of the second inner cavity. A second limiting plate (16) is slidably installed in the second inner cavity. A blocking rod (1) is fixedly installed on the lower wall of the second limiting plate (16). 7) The lower end of the blocking rod (17) passes through the first through hole. A second spring (18) is fixedly installed between the lower wall of the second limiting plate (16) and the lower wall of the second inner cavity. The second spring (18) is fitted onto the blocking rod (17). A ball (19) is movably installed on the upper wall of the second limiting plate (16). The ball (19) passes through the second through hole. An external thread (20) is opened on the outer wall of the cylinder (15). A first internal thread sleeve (21) is connected to the outer wall of the cylinder (15). The inner wall section of the first internal thread sleeve (21) near the second connecting frame plate (4) has an inclined structure.

2. A duct structure for building ventilation according to claim 1, characterized in that, The shock absorption assembly includes a slide rail (22), which is fixedly installed on the four walls inside the bearing frame (2). A pair of moving blocks (23) are slidably installed inside the slide rail (22). A third spring (24) is fixedly installed between the moving blocks (23) and the slide rail (22). A connecting rod (25) is hinged to the moving blocks (23), and the other end of the connecting rod (25) is hinged to the outer wall of the duct body (1).

3. A duct structure for building ventilation according to claim 2, characterized in that, The lifting assembly includes a pair of lifting cylinders (26). The lower end of each lifting cylinder (26) has an open structure. A second internally threaded sleeve (27) is rotatably mounted on the lower end of each lifting cylinder (26). A lead screw (28) is screwed into the second internally threaded sleeve (27). Guide grooves (29) are respectively opened on the inner side walls of each lifting cylinder (26). Guide blocks (30) are slidably mounted in the guide grooves (29). The upper end of the lead screw (28) is fixedly mounted between the guide blocks (30). A driven gear (31) is fixedly mounted on the outer wall of the second internally threaded sleeve (27). A housing (3) is fixedly mounted between the lifting cylinders (26). 2) The second internal threaded sleeve (27) is located inside the box (32). A pair of support plates (33) are fixedly installed inside the box (32). A rotating rod (34) is rotatably installed between the pair of support plates (33). A drive gear (35) is fixedly installed at both ends of the rotating rod (34). The drive gear (35) meshes with the driven gear (31). A handwheel (36) is fixedly installed on the rotating rod (34) between the pair of support plates (33). The handwheel (36) passes through the upper and lower walls of the box (32). The lower end of the screw (28) is fixedly installed on the side wall of the bearing frame (2) through a threaded block.

4. A duct structure for building ventilation according to claim 3, characterized in that, Both the driving gear (35) and the driven gear (31) are bevel gear structures.

5. A duct structure for building ventilation according to claim 4, characterized in that, The main body (1) of some of the ducts is one or a combination of two of the following: a square tube or an arc tube.

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