Insulation Structure of a Spiral Air Duct and Its Installation Method

Abstract

This application relates to the field of air ducts, and in particular to a heat insulation structure for a spiral air duct and its installation method. It includes a spiral air duct body and a connecting pipe for connecting adjacent spiral air duct bodies. The connecting pipe is coaxially arranged with the spiral air duct body. A hoop for fastening the connecting pipe and the spiral air duct body is provided on the connecting pipe. Connecting grooves are provided at both ends of the connecting pipe. A sealing layer is connected to the side wall of the connecting groove. The sealing layer is slidably matched with the connecting groove along the radial direction of the connecting pipe. A push rod is slidably connected to the side wall of the connecting groove along the radial direction of the connecting pipe. The push rod penetrates through the side wall of the connecting groove and is connected to the sealing layer. This application has the effect of improving the heat insulation effect of the air duct.

Description

Technical Field

[0001] This application relates to the field of air ducts, and particularly to a heat insulation structure for a spiral air duct and an installation method thereof. Background Art

[0002] Air ducts are mainly used to connect the air circulation between two places and play the role of ventilation. The most widely used air ducts on the market are spiral air ducts.

[0003] A Chinese patent with the publication number CN216813262U, a pre-insulated inner connection pipe for a spiral air duct, includes a first spiral air duct and a second spiral air duct. Two connecting pieces are movably sleeved at opposite ends of the first spiral air duct and the second spiral air duct. Bolts are arranged inside both of the two connecting pieces, and the two connecting pieces are threadedly connected together by the bolts. A first inner pipe is fixed to the inner wall of the first spiral air duct. In the present utility model, the first spiral air duct and the second spiral air duct are installed by cutting their joints. After the sealing ring is inserted into the second inner pipe, the bolts are rotated to screw the two connecting pieces together, thereby fixing the first spiral air duct and the second spiral air duct, facilitating the installation at the cut joints of the first spiral air duct and the second spiral air duct, and preventing the first spiral air duct from tilting and shaking through the limitation of the slider, achieving the effect of assisting the staff in installation, facilitating the staff to install, and the sealing ring playing a sealing effect, making it more convenient to use.

[0004] When connecting the spiral air duct using the above solution, since the connecting pieces are connected by bolts, after the spiral air duct is used for a long time, the bolts are exposed to the external environment for a long time, and the bolts are prone to corrosion, so the connecting pieces are prone to looseness, and a gap appears at the connection between the first spiral air duct and the second spiral air duct, resulting in poor sealing performance of the spiral air duct, and thus poor heat insulation effect of the spiral air duct. Summary of the Invention

[0005] In order to improve the heat insulation effect of the air duct, this application provides a heat insulation structure for a spiral air duct and an installation method thereof.

[0006] The heat insulation structure for a spiral air duct and the installation method provided by this application adopt the following technical solutions:

[0007] A heat insulation structure for a spiral air duct includes a spiral air duct body and a connecting pipe for connecting adjacent spiral air duct bodies. The connecting pipe is coaxially arranged with the spiral air duct body. A hoop for fastening the connecting pipe and the spiral air duct body is arranged on the connecting pipe. Connecting grooves are arranged at both ends of the connecting pipe. A sealing layer is connected to the side wall of the connecting groove. The sealing layer is slidably matched with the connecting groove along the radial direction of the connecting pipe. A top rod is slidably connected to the side wall of the connecting groove along the radial direction of the connecting pipe. The top rod penetrates through the side wall of the connecting groove and is connected to the sealing layer.

[0008] By adopting the above technical solution, the spiral air duct body is inserted into the connection groove, and the spiral air duct body is in interference fit with the connecting pipe through the sealing layer. When the bolts on the hoop are loose, since the spiral air duct body abuts against the sealing layer, the sealing layer fits with the spiral ribs on the outer side of the spiral air duct body and the side wall of the pipe body of the spiral air duct body. The sealing layer reduces the possibility of a gap appearing between the spiral air duct body and the connecting pipe, improves the sealing performance between the spiral air duct body and the connecting pipe, and thus improves the heat preservation effect of the air duct.

[0009] Optionally, a linkage rod is slidably connected to the bottom of the connection groove along the axial direction of the connecting pipe. An installation cavity is arranged in the connecting pipe. The ejector rod and the linkage rod both penetrate through the side wall of the connection groove and extend into the installation cavity. A linkage assembly corresponding to the ejector rod is connected between the linkage rod and the ejector rod, and the linkage assembly is located in the installation cavity.

[0010] By adopting the above technical solution, when the spiral air duct body is inserted into the connection groove, the end of the spiral air duct abuts against the linkage rod. Through the transmission of the linkage assembly, the ejector rod moves towards the spiral air duct, and the ejector rod pushes the sealing layer towards the spiral air duct body, improving the sealing performance between the sealing layer and the spiral air duct body. The sealing layer is pressed tightly against the spiral air duct body, improving the heat preservation effect of the air duct and reducing the relative displacement between the spiral air duct body and the connecting pipe along its axial direction.

[0011] Optionally, the linkage assembly includes a hinge plate, a rack and a gear. The hinge plate is hinged on the side wall of the installation cavity. The length direction of the hinge plate is arranged along the radial direction of the connecting pipe. The linkage rod penetrates through the bottom of the connection groove and is slidably connected to the hinge plate along its length direction. The rack is slidably connected to the side wall of the installation cavity along the axial direction of the connecting pipe through a dovetail block 15. The rack is spaced from the side wall of the installation cavity. One end of the rack close to the hinge plate is slidably matched with the hinge plate along its length direction. The gear is rotatably connected to the side wall of the installation cavity. The gear is spaced from the top of the installation cavity. The ejector rod is slidably connected to the top of the installation cavity. A tooth is connected to the side wall of the ejector rod facing the gear. The ejector rod and the rack are both meshed with the gear. An avoidance opening is arranged on the rack. The ejector rod and the avoidance opening are slidably matched along the radial direction of the connecting pipe.

[0012] By adopting the above technical solution, when the spiral air duct body moves towards the bottom of the connection groove, the end of the spiral air duct body abuts against the linkage rod and moves towards the bottom of the connection groove. The end of the linkage rod connected to the hinge plate moves along the length direction of the hinge plate, and the hinge plate rotates away from the linkage rod. The rack moves in the direction opposite to the linkage rod, and the end of the rack connected to the hinge plate moves along the length direction of the hinge plate. The rack drives the gear to rotate, and the ejector rod moves towards the connection groove, thereby realizing the linkage between the linkage rod and the ejector rod.

[0013] Optionally, two ejector rods are provided, and the ejector rods are arranged on both sides of the linkage rod. Two transmission components are also arranged on both sides of the linkage rod. The ejector rod located on the side of the linkage rod away from the sealing layer is in plug-in fit with the spiral air duct body.

[0014] By adopting the above technical solution, when the linkage rod moves towards the bottom of the connection groove, the ejector rod moves towards the connection groove and inserts into the spiral air duct body, so that the ejector rod limits the spiral air duct body, reducing the possibility of the spiral air duct coming out of the connection groove.

[0015] Optionally, a notch is provided at the end of the connecting pipe. The notch penetrates the inner wall and the outer wall of the connecting pipe, and the notch communicates with the connection groove. A belt groove is provided on the connecting pipe, and a fastening belt is connected to the connecting pipe through the belt groove. The fastening belt penetrates the belt groove, and a ratchet rack is connected to the end of the fastening belt. The ratchet rack is slidably connected to the bottom of the notch along the circumferential direction of the connecting pipe. The ratchet teeth on the ratchet racks at both ends of the fastening belt are arranged oppositely, and a ratchet wheel is rotatably connected to the bottom of the notch. The ratchet rack meshes with the ratchet wheel.

[0016] By adopting the above technical solution, when the ratchet wheel rotates, the two ratchet racks move closer to each other, so that the fastening belt is tightened, making the sealing layer press more tightly against the spiral air duct body, and improving the connection stability between the end of the connecting pipe and the spiral air duct body.

[0017] Optionally, a hoop is sleeved on the ratchet rack.

[0018] By adopting the above technical solution, the hoop plays a protective role for the ratchet rack, and improves the service life of the ratchet rack and the ratchet wheel.

[0019] Optionally, the spiral air duct body includes an inner pipe, an outer pipe, and an intermediate pipe body for heat preservation. The intermediate pipe body is connected between the inner pipe and the outer pipe.

[0020] By adopting the above technical solution, the setting of the intermediate pipe body improves the heat preservation effect of the spiral air duct body.

[0021] Optionally, a spiral groove is provided on the side wall of the middle pipe body, and the spiral groove is arranged opposite to the spiral ribs on the inner pipe and the spiral ribs on the outer pipe.

[0022] By adopting the above technical solution, the spiral ribs are opposite to the spiral groove, and the outer pipe and the inner pipe are rotated, so that the outer pipe, the middle pipe body and the inner pipe are connected together, improving the sealing performance between the middle pipe body and the outer pipe and the inner pipe, and improving the heat preservation effect.

[0023] An installation method for a heat preservation structure of a spiral air duct includes the following steps: S1: Rotate the inner pipe and the outer pipe in opposite directions so that the spiral groove and the spiral ribs are inserted and matched, and connect the middle pipe body between the inner pipe and the outer pipe; S2: Insert the spiral air duct body into the connection groove, the spiral air duct body abuts against the linkage rod and moves, the linkage rod moves towards the hinge plate, the hinge plate rotates, the end of the hinge plate connected to the rack moves in the opposite direction to the linkage rod, and the transmission between the linkage rod and the gear drives the ejector rod to move towards the connection groove. One ejector rod is inserted into the slot on the spiral air duct body to limit the spiral air duct body, and the other ejector rod pushes the sealing layer towards the spiral air duct body, and the sealing layer is pressed tightly against the outer wall of the spiral air duct; S3: Rotate the ratchet teeth so that the ratchet racks move closer to each other, so that the tightening belt drives the end of the connecting pipe with a notch to tighten towards the axis of the connecting pipe, thereby clamping the spiral air duct body. Finally, the hoop is sleeved on the end of the connecting pipe, and the hoop is covered on the ratchet rack to complete the sealed connection between the spiral air duct body and the connecting pipe.

[0024] By adopting the above technical solution, when the spiral air duct body is inserted and connected with the connecting pipe, through the transmission between the linkage rod and the ejector rod, the ejector rod is inserted into the spiral air duct body, and the sealing layer is pressed tightly against the spiral air duct body, thereby reducing the possibility of loosening between the spiral air duct body and the connecting pipe, improving the sealing effect between the spiral air duct body and the connecting pipe, and improving the heat preservation effect of the spiral air duct.

[0025] In summary, the present application includes at least one of the following beneficial technical effects:

[0026] 1. Insert the spiral air duct body into the connection groove, and the spiral air duct body is in interference fit with the connecting pipe through the sealing layer. When the bolts on the hoop are loose, since the spiral air duct body abuts against the sealing layer, the sealing layer fits with the spiral ribs on the outer side of the spiral air duct body and the side wall of the spiral air duct body pipe, and the sealing layer reduces the possibility of gaps between the spiral air duct body and the connecting pipe, improving the sealing performance between the spiral air duct body and the connecting pipe, thereby improving the heat preservation effect of the spiral air duct body;

[0027] 2. When the spiral air duct body is inserted into the connection groove, the end of the spiral air duct abuts against the linkage rod. Through the transmission of the linkage assembly, the ejector rod moves towards the spiral air duct. The ejector rod pushes the sealing layer towards the spiral air duct body, improving the sealing performance between the sealing layer and the spiral air duct body. The sealing layer is pressed tightly against the spiral air duct body, improving the heat preservation effect of the air duct and reducing the relative displacement between the spiral air duct body and the connecting pipe along its axial direction;

[0028] 3. When the spiral air duct body moves towards the bottom of the connection groove, the end of the spiral air duct body abuts against the linkage rod and moves towards the bottom of the connection groove. The end of the linkage rod connected to the hinge plate moves along the length direction of the hinge plate. The hinge plate rotates away from the linkage rod, and the rack moves in the direction opposite to the linkage rod. The end of the rack connected to the hinge plate moves along the length direction of the hinge plate. The rack drives the gear to rotate, and the ejector rod moves towards the connection groove, thus realizing the linkage between the linkage rod and the ejector rod. Description of the Drawings

[0029] Figure 1 is the overall structural schematic diagram for embodying the heat preservation structure of a spiral air duct;

[0030] Figure 2 is the schematic diagram for embodying the positional relationship between the outer pipe and the inner pipe;

[0031] Figure 3 is the schematic diagram for embodying the positional relationship between the connecting pipe and the spiral air duct body;

[0032] Figure 4 is for embodying Figure 3 the enlarged view of part A showing the positional relationship between the arc-shaped plate and the sealing layer in

[0033] Figure 5 is for embodying Figure 3 the enlarged view of part B showing the positional relationship between the gear and the rack in

[0034] Figure 6 is the schematic diagram for embodying the position between the hoop and the connecting pipe;

[0035] Figure 7 is for embodying Figure 6 the enlarged view of part C showing the positional relationship between the ratchet and the ratchet rack in

[0036] Description of the Reference Numerals:

[0037] 1. Spiral duct body; 2. Connecting pipe; 3. Inner pipe; 4. Outer pipe; 5. Intermediate pipe body; 6. Pipe sheet; 7. Frame; 8. First insulation layer; 9. Second insulation layer; 10. First connecting strip; 11. Second connecting strip; 12. Spiral groove; 13. Connecting groove; 14. Notch; 15. Dovetail block; 16. Spherical slider; 17. Linking rod; 18. Hinge plate; 19. Installation cavity; 20. Avoidance; 21. Slide groove; 22. Gear; 23. Push rod; 24. Rack; 25. Support plate; 26. Spacer; 27. Arc plate; 28. Sealing layer; 29. ​​Fastening belt; 30. Ratchet bar; 31. Ratchet; 32. Connecting shaft; 33. Compression spring; 34. Hoop. DETAILED DESCRIPTION

[0038] The embodiment of the present application discloses a thermal insulation structure of a spiral air duct and an installation method thereof.

[0039] Reference Figure 1 , a heat preservation structure of a spiral air duct, comprising a spiral air duct body 1 and a connecting pipe 2 for connecting adjacent spiral air duct bodies 1.

[0040] Reference Figure 1 and Figure 2 The spiral duct body 1 includes an inner tube 3, an intermediate tube body 5 and an outer tube 4. The intermediate tube body 5, the inner tube 3 and the outer tube 4 are all coaxially arranged. The intermediate tube body 5 is located between the inner tube 3 and the outer tube 4. The spiral ribs on the outer tube 4 have a rotation direction opposite to that on the inner tube 3. The outer and inner walls of the intermediate tube body 5 are both provided with spiral grooves 12. The spiral grooves 12 are arranged opposite to the spiral ribs on the outer tube 4 and the spiral ribs on the inner tube 3. The intermediate tube body 5 includes a plurality of tube segments 6 arranged with the axis of the intermediate tube body 5 as the central circumference. The tube segments 6 are arranged in an arc shape. The tube segments 6 include a frame 7, a first insulation layer 8 and a second insulation layer 9. The first insulation layer 8 and the second insulation layer 9 are glass fiber wool. The first insulation layer 8 and the second insulation layer 9 are integrally formed.

[0041] Reference Figure 1 and Figure 2 The first thermal insulation layer 8 and the second thermal insulation layer 9 are arranged along the radial direction of the intermediate tube body 5, and the frame 7 is fixedly connected between the first thermal insulation layer 8 and the second thermal insulation layer 9, so that a cavity is formed between the first thermal insulation layer 8 and the second thermal insulation layer 9, which reduces the heat conduction rate and improves the thermal insulation effect of the spiral duct body 1; the first thermal insulation layer 8 is arranged close to the inner tube 3, and the second thermal insulation layer 9 is arranged close to the outer tube 4. A first connecting strip 10 is connected to a side wall of the first thermal insulation layer 8, and a second connecting strip 11 is connected to the side wall of the second thermal insulation layer 9 away from the first connecting strip 10. The first connecting strip 10 and the second connecting strip 11 are connected to ratchets on the side wall facing the frame 7, and the inclination angles of the ratchets on the first connecting strip 10 and the second connecting strip 11 are opposite.

[0042] Referring to Figure 1 and Figure 3 , the connecting pipe 2 is coaxially arranged with the spiral air duct body 1. Connecting grooves 13 are arranged at both ends of the connecting pipe 2. The spiral air duct body 1 is inserted into the connecting pipe 2 through the connecting grooves 13. Notches 14 are arranged at both ends of the connecting pipe 2. The notches 14 are circumferentially arranged with the axis of the connecting pipe 2 as the center. The notches 14 communicate with the connecting grooves 13, and the notches 14 penetrate through the outer side wall of the connecting pipe 2.

[0043] Referring to Figure 3 and Figure 4 , the installation cavity 19 is annularly arranged. The cross-section of the installation cavity 19 is U-shaped. The opening of the installation cavity 19 faces the connecting groove 13. A sliding hole is arranged at the bottom of the connecting groove 13. A plurality of sliding holes are circumferentially arranged with the axis of the connecting pipe 2 as the center. Two sliding holes are arranged in the radial direction of the connecting pipe 2. The length direction of the sliding hole is arranged along the axial direction of the connecting pipe 2. A plurality of sliding holes are circumferentially arranged with the axis of the connecting pipe 2 as the center. The sliding holes communicate with the installation cavity 19. A linkage rod 17 is slidably connected to the bottom of the connecting groove 13 along the axial direction of the connecting pipe 2 through the sliding holes.

[0044] Referring to Figure 3 and Figure 4 , a linkage assembly corresponding to the linkage rod 17 is arranged in the installation cavity 19. The linkage assembly is located on the side where the linkage rods 17 are far away from each other. The linkage assembly includes a hinged plate 18. The hinged plate 18 is hinged on the side wall of the installation cavity 19. A torsion spring is sleeved on the hinge shaft between the hinged plate 18 and the installation cavity 19. When the torsion spring is in a natural state, the hinged plate 18 is horizontally arranged. Chute 21 is arranged at both ends of the side wall of the hinged plate 18 facing the bottom of the connecting groove 13 along the length direction of the hinged plate 18. The cross-section of the chute 21 is arc-shaped. A spherical slider 16 is connected to one end of the linkage rod 17 facing the hinged plate 18. The spherical slider 16 is located in the chute 21 and is slidably matched with the chute 21.

[0045] Referring to Figure 3 , Figure 4 and Figure 5, a rack 24 is slidably connected along the axial direction of the connecting pipe 2 on the side wall of the installation cavity 19 facing the linkage rod 17. A dovetail groove is provided along the axial direction of the connecting pipe 2 on the side wall of the installation cavity 19. A dovetail block 15 is connected to the rack 24 through a spacer block 26. The dovetail block 15 is located in the dovetail groove and is slidably matched with the dovetail groove. The rack 24 is spaced from the side wall of the installation cavity 19; support plates 25 are connected to the top of the installation cavity 19 and the top of the linkage cavity. A gear 22 is rotatably connected to the support plate 25. A push rod 23 is slidably connected along the radial direction of the connecting pipe 2 on the top of the installation cavity 19. The push rod 23 is located on the side of the gear 22 away from the hinge plate 18. Teeth are provided on the push rod 23. An avoidance opening 20 is provided on the rack 24. The push rod 23 penetrates through the avoidance opening 20 and is slidably matched with the avoidance opening 20. Both the rack 24 and the push rod 23 are meshed with the gear 22. A rod groove is provided on the side wall of the spiral air duct body 1 facing the axis of the connecting pipe 2. The push rod 23 penetrates through the side wall of the connecting groove 13 and is inserted and matched with the rod groove.

[0046] Refer to Figure 3 and Figure 4 , a sliding opening is provided on the side wall of the connecting groove 13 away from the axis of the connecting pipe 2. A sealing layer 28 is connected to the side wall of the connecting groove 13. The sealing layer 28 is made of rubber. The sealing layer 28 is located in the sliding opening. An arc-shaped plate 27 is connected to the push rod 23 arranged away from the axis of the connecting pipe 2. The arc-shaped plate 27 is located in the installation cavity 19. The arc-shaped plate 27 is slidably connected along the radial direction of the connecting pipe 2 with the top of the installation cavity 19. The arc-shaped plate 27 is connected to the sealing layer 28.

[0047] Refer to Figure 6 and Figure 7 , a belt groove is provided on the connecting pipe 2. The belt groove is arranged in a spiral shape. The belt groove is communicated with the notch 14. A fastening belt 29 is connected to the connecting pipe 2 through the belt groove. The fastening belt 29 is made of a flexible material. Ratchet teeth are provided at both ends of the fastening belt 29. The ratchet teeth on the ratchet racks 30 at both ends of the fastening belt 29 are arranged oppositely. The ratchet racks 30 are slidably connected along the circumferential direction of the connecting pipe 2 with the bottom of the notch 14. A through hole is provided at the bottom of the notch 14. The length direction of the through hole is arranged along the axial direction of the connecting pipe 2. A connecting shaft 32 is slidably connected along the axial direction of the connecting pipe 2 on the connecting pipe 2 through the through hole. A compression spring 33 is sleeved on the connecting shaft 32. A ratchet wheel 31 is rotatably connected to the connecting shaft 32 through a rotating shaft. The compression spring 33 is located between the ratchet wheel 31 and the bottom of the notch 14. When the compression spring 33 is in a natural state, the ratchet racks 30 are located on both sides of the ratchet wheel 31 and are meshed with the ratchet wheel 31. A hoop 34 is sleeved on the connecting pipe 2. The hoop 34 covers the ratchet racks 30.

[0048] An installation method for the heat insulation structure of a spiral air duct includes the following steps:

[0049] S1: Assemble the segments 6 together. Insert the first connecting strip 10 and the second connecting strip 11 vertically into each other so that the segments 6 are assembled into the middle pipe body 5. Then, align the spiral grooves 12 on the inner sidewall of the middle pipe body 5 with the spiral ribs on the inner pipe 3, and rotate the inner pipe 3 to connect the inner pipe 3 with the middle pipe body 5. Align the spiral grooves 12 on the outer sidewall of the middle pipe body 5 with the spiral ribs on the outer pipe 4, and rotate the outer pipe 4 in the direction opposite to that of the inner pipe 3 to connect the outer pipe 4 with the middle pipe body 5, thus completing the connection of the spiral air duct body 1.

[0050] S2: Insert the spiral air duct body 1 into the connection groove 13. When the spiral air duct body 1 moves towards the bottom of the connection groove 13, the end of the spiral air duct body 1 facing the connecting pipe 2 abuts against the linkage rod 17, causing the linkage rod 17 to move towards the bottom of the connection groove 13. The linkage rod 17 moves along the sliding hole, moves towards the hinge plate 18, and the end of the linkage rod 17 connected to the hinge plate 18 moves along the length direction of the hinge plate 18. The spherical slider 16 moves along the chute 21, the hinge plate 18 rotates, and the end of the hinge plate 18 connected to the rack 24 moves in the direction opposite to that of the linkage rod 17. The end of the rack 24 connected to the hinge plate 18 moves along the length direction of the hinge plate 18, and the rack 24 moves vertically away from the hinge plate 18. The dovetail block 15 moves along the dovetail groove. The rack 24 drives the gear 22 to rotate. Under the drive of the gear 22, the ejector rod 23 moves towards the connection groove 13. The ejector rod 23 arranged close to the axis of the connecting pipe 2 penetrates the sidewall of the connection groove 13 and is inserted into the rod groove on the inner pipe 3. The ejector rod 23 arranged away from the axis of the connecting pipe 2 pushes the arc plate 27, the arc plate 27 pushes the sealing layer 28, and the sealing layer 28 moves towards the spiral air duct body 1, and the sealing layer 28 fits against the spiral ribs on the outer side of the spiral air duct body 1 and the sidewall of the pipe body of the spiral air duct body 1. Since the rotation direction of the middle pipe body 5 is opposite to that between the outer pipe 4 and the inner pipe 3, after the spiral air duct body 1 is inserted into the connection groove 13, the ejector rod 23 and the sealing layer 28 fix the end of the spiral air duct body 1 in the connection groove 13, and the middle pipe body 5 is not easily separated from the outer pipe 4 and the inner pipe 3.

[0051] S3: Rotate the ratchet 31 so that the ratchet racks 30 move closer to each other, thereby driving the tightening belt 29 to tighten the end of the connecting pipe 2 with the notch 14 towards the axis of the connecting pipe 2, thus clamping the spiral air duct body 1. Finally, put the hoop 34 on the end of the connecting pipe 2 and make the hoop 34 cover the ratchet racks 30, completing the sealed connection between the spiral air duct body 1 and the connecting pipe 2.

Claims

1. A heat insulation structure for a spiral air duct, comprising a spiral air duct body (1) and a connecting pipe (2) for connecting adjacent spiral air duct bodies (1). The connecting pipe (2) is coaxially arranged with the spiral air duct body (1), and a hoop (34) for fastening the connecting pipe (2) and the spiral air duct body (1) is arranged on the connecting pipe (2), characterized in that: Both ends of the connecting pipe (2) are provided with connecting grooves (13). A sealing layer (28) is connected to the side wall of the connecting groove (13). The sealing layer (28) is slidably engaged with the connecting groove (13) along the radial direction of the connecting pipe (2). A push rod (23) is slidably connected to the side wall of the connecting groove (13) along the radial direction of the connecting pipe (2). The push rod (23) penetrates through the side wall of the connecting groove (13) and is connected to the sealing layer (28). A linkage rod (17) is slidably connected to the bottom of the connecting groove (13) along the axial direction of the connecting pipe (2). An installation cavity (19) is arranged inside the connecting pipe (2). The push rod (23) and the linkage rod (17) both penetrate through the side wall of the connecting groove (13) and extend into the installation cavity (19). A linkage assembly corresponding to the push rod (23) is connected between the linkage rod (17) and the push rod (23). The linkage assembly is located inside the installation cavity (19). An opening (14) is arranged at the end of the connecting pipe (2). The opening (14) penetrates through the outer wall of the connecting pipe (2). The opening (14) is communicated with the connecting groove (13). A belt groove is arranged on the connecting pipe (2). A fastening belt (29) is connected to the connecting pipe (2) through the belt groove. The fastening belt (29) penetrates through the belt groove. A ratchet rack (30) is connected to the end of the fastening belt (29). The ratchet rack (30) is slidably connected to the bottom of the opening (14) along the circumferential direction of the connecting pipe (2). The ratchet teeth on the ratchet racks (30) at both ends of the fastening belt (29) are arranged oppositely. A ratchet wheel (31) is rotatably connected to the bottom of the opening (14). The ratchet rack (30) is engaged with the ratchet wheel (31). The hoop (34) is covered on the ratchet rack (30).The linkage assembly includes a hinge plate (18), a rack (24) and a gear (22). The hinge plate (18) is hinged to the side wall of the installation cavity (19). The length direction of the hinge plate (18) is arranged along the radial direction of the connecting pipe (2). The linkage rod (17) penetrates through the bottom of the connecting groove (13) and is slidably connected to the hinge plate (18) along its length direction. The rack (24) is slidably connected to the side wall of the installation cavity (19) along the axial direction of the connecting pipe (2) through a dovetail block 15. The rack (24) is spaced from the side wall of the installation cavity (19). One end of the rack (24) close to the hinge plate (18) is slidably matched with the hinge plate (18) along its length direction. The gear (22) is rotatably connected to the side wall of the installation cavity (19). The gear (22) is spaced from the top of the installation cavity (19). The ejector rod (23) is slidably connected to the top of the installation cavity (19). A tooth is connected to the side wall of the ejector rod (23) facing the gear (22). Both the ejector rod (23) and the rack (24) are meshed with the gear (22). An avoidance opening (20) is arranged on the rack (24). The ejector rod (23) and the avoidance opening (20) are slidably matched along the radial direction of the connecting pipe (2).; 2. The thermal insulation structure of a spiral air duct according to claim 1, wherein: There are two of the ejector rods (23), and the ejector rods (23) are arranged on both sides of the linkage rod (17). The two linkage assemblies are also arranged on both sides of the linkage rod (17). The ejector rod (23) located on the side of the linkage rod (17) away from the sealing layer (28) is in plug-in fit with the spiral air duct body (1).

3. The thermal insulation structure of a spiral air duct according to claim 2, characterized in that: The spiral air duct body (1) includes an inner pipe (3), an outer pipe (4), and an intermediate pipe body (5) for heat preservation. The intermediate pipe body (5) is detachably connected between the inner pipe (3) and the outer pipe (4).

4. The thermal insulation structure of a spiral air duct according to claim 3, wherein: The helix direction of the spiral ribs on the inner pipe (3) is opposite to the helix direction of the spiral ribs on the outer pipe (4). A spiral groove (12) is provided on the side wall of the intermediate pipe body (5), and the spiral groove (12) is arranged opposite to the spiral ribs on the inner pipe (3) and the spiral ribs on the outer pipe (4).

5. A method for installing a heat insulation structure of a spiral air duct as described in claim 4, characterized in that: It includes the following steps: S1: Rotate the inner pipe (3) and the outer pipe (4) in opposite directions so that the spiral groove (12) is in plug-in fit with the spiral ribs, and connect the intermediate pipe body (5) between the inner pipe (3) and the outer pipe (4). S2: Insert the spiral air duct body (1) into the connection groove (13). The spiral air duct body (1) abuts against the linkage rod (17) and moves. The linkage rod (17) moves towards the hinge plate (18). The hinge plate (18) rotates. One end of the hinge plate (18) connected to the rack (24) moves in the opposite direction to the linkage rod (17). The transmission between the linkage rod (17) and the gear (22) drives the ejector rod (23) to move towards the connection groove (13). One ejector rod (23) is inserted into the spiral air duct body (1) for positioning, and the other ejector rod (23) pushes the sealing layer (28) towards the spiral air duct body (1), and the sealing layer (28) is pressed tightly against the outer wall of the spiral air duct. S3: Rotate the ratchet wheel (31) so that the ratchet racks (30) move closer to each other. Thus, the tightening belt (29) drives the end of the connecting pipe (2) provided with the notch (14) to tighten towards the axis of the connecting pipe (2), thereby clamping the spiral air duct body (1). Finally, the hoop (34) is sleeved on the end of the connecting pipe (2), and the hoop (34) is made to cover the ratchet racks (30) to complete the sealed connection between the spiral air duct body (1) and the connecting pipe (2).

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