Sealing device for composite steel pipe coating process

Abstract

This utility model discloses a sealing device for the coating process of composite steel pipes, belonging to the field of composite steel pipe manufacturing technology. It solves the problems of excessively high surface temperature, frequent thermal shock cracks, and liquid metal leakage caused by the rapid heat conduction of the existing QT350 clamp. Key technical points include: a sleeve is fitted over the steel pipe with fiber paper resistant to 1400℃ pasted on its inner wall; a sealing plate is tightly attached to the end of the steel pipe, and an end plate is fixed to the sealing plate; multiple pairs of L-shaped connecting plates are provided on the outer wall of the sleeve; an extension plate passes through the sleeve opening and is opposite to an eccentric block; a rotating shaft passes through the opening of the connecting plate and is fixed to the eccentric block; the eccentric block presses against the connecting plate, causing the rotating shaft to move away from the extension plate, stretching springs fixed at both ends to the extension plate and the rotating shaft; after the fixing bolts are tightened, a continuous axial clamping force is provided; positioning bolts fix the sleeve to the steel pipe. Its main purpose is to seal the ends of high-temperature rotating steel pipes in the centrifugal aluminothermic coating process, preventing leakage and extending the life of the device.

Description

Technical Field

[0001] This utility model relates to the field of composite steel pipe manufacturing technology. More specifically, this utility model relates to a sealing device for the coating process of composite steel pipes. Background Technology

[0002] Composite steel pipe is a type of steel pipe that uses steel pipe as the base pipe and plastic powder or metal powder as the coating material, with a layer of plastic, metal or other anti-corrosion material coated on its inner surface. Due to its excellent mechanical properties and corrosion resistance, composite steel pipe is widely used in water supply and drainage, fire protection systems, chemical and industrial fields.

[0003] Before lining a composite steel pipe with metal powder as the coating material, a layer of high-combustion-value metal composite powder is uniformly filled into the lower part of the pipe along its radial direction. While the metal composite powder burns, the pipe rotates at high speed. The burning powder becomes liquid and, after a period of time, adheres evenly to the inner wall of the pipe under centrifugal force, forming the inner lining. The burning powder releases a large amount of heat in a short time, causing the internal temperature of the pipe to rise to approximately 1500°C. To prevent the powder from being ejected during the rotation and combustion process, sealing devices are added to both ends of the pipe. However, due to the rapid increase in internal temperature, the surface temperature of these sealing devices reaches 200–550°C. The existing sealing devices use QT350 material. Due to the effects of high temperatures, cracks and peeling occur after 2-4 uses, rendering the devices unusable. Furthermore, the high thermal conductivity of QT350 material means that the surface temperature of the device remains high after coating the steel pipe, requiring manual water cooling before reuse, reducing production efficiency and increasing costs. During high-speed rotation of the composite steel pipe, incomplete contact between the pipe end face and the sealing device end face can cause liquid metal composite powder to overflow from the end, leading to adhesion between the device and the composite steel pipe and rendering the composite steel pipe unusable. Utility Model Content

[0004] The purpose of this invention is to provide a sealing device for the coating process of composite steel pipes. The outer temperature of the sleeve is reduced to 100°C through the fiber paper insulation layer, allowing for disassembly without water cooling. The mechanical linkage between the spring and the eccentric block provides continuous axial clamping force, improving the sealing performance between the sealing plate and the steel pipe. The combination of stainless steel and fiber paper enhances thermal shock resistance.

[0005] Solve the problems of high-temperature rapid heat conduction, material leakage at the end face, and thermal shock cracks.

[0006] This solves the problem of the fiber paper not being firmly fixed to the inner wall of the sleeve.

[0007] This solves the problem of cumbersome operation caused by the complex structure of multiple connecting plates.

[0008] This solves the problems of the pressure plate scratching the fiber paper and excessive heat conduction.

[0009] Solve the problem of sleeve dislodging during high-speed rotation.

[0010] Solve the problem of shaft misalignment caused by single-point force on the eccentric block.

[0011] This solves the problem of the laboriousness of manually rotating the shaft.

[0012] Solve the problem of excessive costs caused by redundant endplate materials.

[0013] To address the aforementioned issues, a sealing device for the coating process of composite steel pipes is provided, comprising:

[0014] A sleeve, one end of which is fitted and fixed to the outside of a steel pipe, and the other end extending to the outside of the end of the steel pipe, and having multiple openings thereon, is coaxially arranged with the steel pipe. The inner wall of the sleeve is provided with a heat insulation layer, and the outer wall is fixed with multiple pairs of connecting plates. Each connecting plate is L-shaped and consists of a first plate and a second plate. Each first plate is parallel to the axis of the sleeve and has an opening extending along the axis of the sleeve. In any pair of first plates, at least one first plate has a fixing hole.

[0015] A blocking plate is attached to the end of the steel pipe and located inside the sleeve;

[0016] The end plate is fixedly connected to the blocking plate and is located inside the sleeve and outside the blocking plate. The end plate is provided with multiple extension plates, and the extension plates, openings and connecting plates correspond one-to-one and extend to the outside of the sleeve after passing through their corresponding openings. Each second plate is close to its corresponding extension plate.

[0017] Multiple shafts, with one shaft inserted through each pair of openings;

[0018] Multiple pairs of eccentric blocks are provided. Each pair of eccentric blocks is fixed on a rotating shaft. Each pair of eccentric blocks is opposite to a pair of second plates. The center of each eccentric block does not coincide with the axis of the rotating shaft. Fixing bolts are respectively installed on the eccentric blocks corresponding to the first plates with fixing holes.

[0019] Multiple elastic elements, with each elastic element, extension plate, and rotating shaft corresponding to one another. The two ends of each elastic element are fixed to the corresponding extension plate and rotating shaft, respectively.

[0020] In this configuration, for any given shaft, when the shaft rotates, a pair of eccentric blocks corresponding to it press against a pair of second plates corresponding to it, causing the shaft to move away from the corresponding extension plate in a pair of corresponding openings and stretching the elastic element until the fixing bolt and the corresponding fixing hole are aligned; when the fixing bolt is screwed into the corresponding fixing hole, the shaft is fixed on a pair of first plates; channels are provided on the end plate and the end plate.

[0021] Preferably, in the sealing device for the coating process of composite steel pipe, the inner wall of the sleeve is provided with an annular mounting groove along its circumferential direction, the part of the sleeve located in the mounting groove is pasted with a heat insulation layer, the heat insulation layer is fiber paper, and fiber paper is also pasted between the blocking plate and the end plate.

[0022] The sealing device used in the coating process of composite steel pipes also includes:

[0023] Multiple pressure plates are evenly spaced along the circumferential direction of the sleeve. Each pressure plate is T-shaped. The protrusion in the middle of each pressure plate is inserted into the mounting groove and presses the fiber paper. The two sides abut against the two sides of the mounting groove. The side of each pressure plate opposite to the steel pipe is arc-shaped. The pressure plates and the sleeve are fixed by bolts passing through them.

[0024] Preferably, in the sealing device used in the coating process of composite steel pipes, the maximum heat resistance temperature of the fiber paper is 1400℃.

[0025] Preferably, in the sealing device for the coating process of composite steel pipe, there are two pairs of connecting plates, which are symmetrically arranged on the sleeve. In any pair of first plates, only one first plate has a fixing hole.

[0026] Preferably, in the sealing device used in the coating process of composite steel pipes, the elastic element is a spring.

[0027] Preferably, in the sealing device for the coating process of composite steel pipes, there is a gap between the pressure plate and the steel pipe.

[0028] Preferably, in the sealing device for the coating process of composite steel pipe, a plurality of positioning bolts and a plurality of limiting bolts are spaced along the circumferential direction on the sleeve. Each positioning bolt abuts against the steel pipe and fixes the sleeve to the steel pipe. Each limiting bolt is located on the outside of the end plate and abuts against the end plate.

[0029] Preferably, in the sealing device for the coating process of composite steel pipe, each pair of eccentric blocks is respectively arranged at both ends of the corresponding rotating shaft, each pair of first plates is respectively arranged between the corresponding pair of eccentric blocks, and the two ends of the spring are respectively fixed to the middle of the corresponding extension plate and the rotating shaft.

[0030] Preferably, in the sealing device for the coating process of composite steel pipe, each rotating shaft is provided with a handle. The handle is U-shaped, and the two ends of the handle are fixedly connected to the two ends of the rotating shaft. When the handle is rotated toward the side where the spring is located, the spring is stretched.

[0031] Preferably, in the sealing device for the coating process of composite steel pipes, both the end plate and the plug are annular, and the inner diameter of the plug is smaller than the inner diameter of the end plate.

[0032] This utility model has at least the following beneficial effects:

[0033] This invention utilizes a heat-insulating layer structure (such as fiber paper) on the inner wall of the sleeve to block heat transfer, reducing the outer temperature of the sleeve to below 100℃, eliminating the need for water-cooled disassembly. A mechanical linkage structure (combination of a rotating shaft, eccentric block, spring, connecting plate, and extension plate) of an eccentric block and spring converts rotational motion into axial displacement, providing continuous clamping force and enhancing the sealing performance between the plug plate and the steel pipe. The combination of a stainless steel sleeve and fiber paper reduces thermal stress and minimizes the risk of thermal shock cracking.

[0034] This invention provides precise positioning space for fiber paper through an annular mounting groove structure on the inner wall of the sleeve. The structure, in which the T-shaped pressure plate is inserted into the mounting groove at the center and the side flanges press against the groove wall, evenly compacts the fiber paper and prevents it from falling off.

[0035] This invention uses ceramic fiber paper material with a maximum temperature resistance of 1400℃, combined with a high-temperature adhesive bonding structure, to ensure that the heat insulation layer does not fail under high-temperature conditions.

[0036] This utility model adopts a structure of two pairs of symmetrically arranged connecting plates, which simplifies the operation steps.

[0037] This utility model uses a helical spring as the elastic element, and provides axial clamping force to the pressure plate through the assembly structure in which its two ends are fixed to the extension plate and the middle of the rotating shaft.

[0038] This invention reduces heat conduction and prevents fiber paper from being scratched by a physical isolation structure with a 1-2mm gap between the curved surface of the pressure plate and the outer wall of the steel pipe.

[0039] This invention utilizes multiple circumferentially distributed positioning bolts on the sleeve to tighten against the outer wall of the steel pipe, achieving rigid fixation between the sleeve and the steel pipe and preventing axial dislocation of the sleeve due to centrifugal force during high-speed rotation. Limiting bolts at the end of the sleeve abut against the outer side of the end plate, restricting axial displacement of the end plate under high-temperature thermal expansion and preventing liquid metal leakage caused by separation of the plug plate from the end face of the steel pipe. The positioning bolts and limiting bolts form a mechanical interlock, maintaining the stable position of the sleeve and end plate under high-temperature and high-speed conditions, ensuring the integrity of the sealing structure and extending the service life of the device.

[0040] This invention uses a structure with eccentric blocks symmetrically arranged at both ends of the rotating shaft and a pair of first plates centrally distributed to balance bidirectional forces and prevent the rotating shaft from tilting.

[0041] This invention reduces the manual rotation force by using a lever structure with U-shaped handles welded to both ends of the rotating shaft.

[0042] This invention uses a stepped ring structure with the inner diameter of the blocking plate smaller than that of the end plate to reduce the amount of material used while ensuring structural strength.

[0043] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the sealing device from one angle;

[0045] Figure 2 This is a schematic diagram of the sealing device from another angle;

[0046] Figure 3 This is a cross-sectional view of the sealing device. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0048] It should be noted that in the description of this utility model, the terms "horizontal", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0049] like Figures 1 to 3 As shown, this utility model provides a sealing device for the coating process of composite steel pipes, comprising:

[0050] A sleeve 1 is fitted and fixed at one end to the outside of a steel pipe 2, and extends to the outside of the end of the steel pipe 2 at the other end. Multiple openings 101 are provided on the sleeve 1. The sleeve 1 is coaxially arranged with the steel pipe 2. A heat insulation layer 3 (which can be fiber paper or ceramic) is provided on the inner wall of the sleeve 1, and multiple pairs of connecting plates 4 are fixed on the outer wall. Each connecting plate 4 is L-shaped and consists of a first plate 41 and a second plate 42. Each first plate 41 is parallel to the axis of the sleeve 1 and has an opening 411 extending along the axis of the sleeve 1. At least one of any pair of first plates 41 has a fixing hole 412. The opening 411 is long enough to allow the rotating shaft 7 to slide within the opening 411 under the action of the eccentric block 8 when it rotates.

[0051] The blocking plate 5 is attached to the end of the steel pipe 2 and located inside the sleeve 1. The two end faces of the blocking plate 5 are machined to improve their surface roughness and flatness, so as to improve the fit between the blocking plate 5 and the steel pipe 2 and reduce the adhesion between its end face and the coating material of the liquid steel pipe 2.

[0052] End plate 6 is fixedly connected to end plate 5 and located inside sleeve 1 and outside end plate 5. Multiple extension plates 61 are provided on the outer edge of end plate 6. Each extension plate 61 corresponds to an opening 101 and a pair of connecting plates 4, and extends to the outside of sleeve 1 after passing through the opening 101 corresponding to it. Each second plate 42 is close to the extension plate 61 corresponding to it.

[0053] Multiple rotating shafts 7 are inserted into each pair of openings 411;

[0054] Multiple pairs of eccentric blocks 8 are provided. Each pair of eccentric blocks 8 is fixed on each rotating shaft 7. Each pair of eccentric blocks 8 is opposite to a pair of second plates 42. The center of each eccentric block 8 does not coincide with the axis of the rotating shaft 7. Fixing bolts 81 are respectively passed through the eccentric blocks 8 corresponding to the first plate 41 with fixing holes 412.

[0055] Multiple elastic elements 12, each elastic element 12 corresponds to an extension plate 61 and a rotating shaft 7 respectively, and the two ends of each elastic element 12 are fixed to the extension plate 61 and the rotating shaft 7 respectively.

[0056] In this configuration, for any one of the rotating shafts 7, when the shaft 7 rotates, the pair of eccentric blocks 8 corresponding to it press against the pair of second plates 42 corresponding to it, causing the shaft 7 to move away from the corresponding extension plate 61 in the pair of corresponding openings 411 and stretch the elastic element 12 until the fixing bolt 81 and the corresponding fixing hole 412 are aligned; when the fixing bolt 81 is screwed into the corresponding fixing hole 412, the shaft 7 is fixed on the pair of first plates 41; the end plate 6 and the blocking plate 5 are provided with channels for the metal composite powder ignition lead.

[0057] One end of the sleeve 1 is fitted over the steel pipe 2, and the other end extends to the outside of the end of the steel pipe 2. It is provided with multiple openings 101. The sleeve 1 is coaxial with the steel pipe 2. The inner wall is provided with a heat insulation layer 3, and multiple pairs of L-shaped connecting plates 4 are fixed on the outer wall. The connecting plate 4 is composed of a first plate body 41 and a second plate body 42. The first plate body 41 is parallel to the axis of the sleeve 1 and is provided with an opening 411 extending along the axis of the sleeve 1. At least one of any pair of first plates 41 is provided with a fixing hole 412.

[0058] The sleeve 1 can have 2 or 4 openings 101. The insulation layer 3 can be 5-10mm thick. The diameter of the opening 411 in the first plate 41 can be 10-15mm, and the fixing hole 412 can be an M10 or M12 threaded hole. The sleeve 1 can be made of 304 stainless steel; the insulation layer 3 can be made of ceramic or fiber paper; the connecting plate 4 can be made of ordinary carbon steel plate. The sleeve 1 is coaxially fitted onto the outside of the steel pipe 2 and fixed to the steel pipe 2 by positioning bolts 10. The connecting plate 4 is welded to the outer wall of the sleeve 1; the insulation layer 3 is pasted onto the inner wall of the sleeve 1. When the steel pipe 2 rotates, the insulation layer 3 blocks heat transfer.

[0059] The fiber paper can be an industrial-grade ceramic fiber product. Disassembly can be performed without water cooling by reducing external temperature.

[0060] The blocking plate 5 is attached to the end of the steel pipe 2 and located inside the sleeve 1; the end plate 6 is fixedly connected to the blocking plate 5, placed inside the sleeve 1 and located outside the blocking plate 5; multiple extension plates 61 are provided at intervals along the circumferential direction of the sleeve 1 at the outer edge of the end plate 6, each extension plate 61 corresponds to an opening 101 and a pair of connecting plates 4, each extension plate 61 passes through the opening 101 and extends to the outside of the sleeve 1; the second plate 42 is close to its corresponding extension plate 61.

[0061] The number of extension plates 61 can be selected as 2-4 pieces, and the thickness is selected as 10-15mm. The blocking plate 5 can be made of 310S stainless steel; the end plate 6 can be made of 316 stainless steel. Assembly position: the blocking plate 5 is close to the end face of the steel pipe 2, and the end plate 6 is fixed to the blocking plate 5 with bolts; the extension plate 61 passes through the opening 101 on the sleeve 1 and extends to the outside of the sleeve 1.

[0062] During operation, the sealing plate 5 seals the end of the steel pipe 2. The extension plate 61 and the rotating shaft 7 work indirectly through the eccentric block 8, which stretches the elastic element 12, thereby making the sealing plate 5 tightly adhere to the end face of the steel pipe 2 to improve the end sealing performance.

[0063] A rotating shaft 7 is inserted through each pair of openings 411; a pair of eccentric blocks 8 are fixed on each rotating shaft 7, and the center of the eccentric block 8 does not coincide with the axis of the rotating shaft 7; a fixing bolt 81 is provided on the eccentric block 8 corresponding to the first plate 41 with fixing hole 412.

[0064] The diameter of the rotating shaft 7 can be selected from 20-25mm, and the eccentricity of the eccentric block 8 is 2-5mm. The fixing bolt 81 can be an M8 hex socket head cap screw. The elastic element 12 can be a stainless steel coil spring. The rotating shaft 7 can be made of 40Cr alloy steel; the eccentric block 8 can be made of 45 steel. The rotating shaft 7 passes through a pair of openings 411, and the eccentric block 8 is fixed at both ends of the rotating shaft 7; one end of the spring is fixed to the extension plate 61, and the other end is fixed to the middle of the rotating shaft 7.

[0065] When the shaft 7 rotates, the eccentric block 8 presses against the second plate 42. However, since the second plate 42 is fixed on the sleeve 1, the eccentric block 8 moves away from the second plate 42, which causes the shaft 7 to slide away from the extension plate 61 in the opening 411 and stretch the elastic element 12 until the fixing bolt 81 is aligned with the fixing hole 412. After the fixing bolt 81 is screwed in, the shaft 7 is fixed and the clamping force is maintained.

[0066] The rotation angle of the rotating shaft 7 can be selected from 90-180°. U-shaped handles 13 can be used as the operating tool, welded to both ends of the rotating shaft 7. This device reduces the external temperature of the sleeve 1 to below 100℃ through the heat insulation layer 3, eliminating the need for water cooling during disassembly. The eccentric block 8, linked to the spring, provides continuous axial clamping force, enhancing the sealing between the plug plate 5 and the steel pipe 2 and preventing material leakage. The combination of stainless steel material and the heat insulation layer 3 reduces thermal shock cracking and extends service life.

[0067] In another embodiment, in the sealing device for the coating process of the composite steel pipe 2, the inner wall of the sleeve 1 is provided with an annular mounting groove along its circumferential direction, and the part of the sleeve 1 located in the mounting groove is pasted with a heat insulation layer 3, which is fiber paper. Fiber paper is also pasted between the blocking plate 5 and the end plate 6.

[0068] To ensure that the fiber paper is more securely fixed to the sleeve 1, the sealing device used in the coating process of the composite steel pipe 2 also includes:

[0069] Multiple pressure plates 9 are evenly spaced along the circumferential direction of the sleeve 1. Each pressure plate 9 is T-shaped. The protrusion in the middle of each pressure plate 9 is inserted into the mounting groove and presses the fiber paper. The two sides abut against the two sides of the mounting groove respectively. The side of each pressure plate 9 opposite to the steel pipe 2 is arc-shaped. The pressure plates 9 and the sleeve 1 are fixed by bolts passing through them.

[0070] A ring-shaped mounting groove is provided circumferentially on the inner wall of sleeve 1, and a heat insulation layer 3 is pasted inside the mounting groove; the heat insulation layer 3 is fiber paper. The depth of the mounting groove can be selected as 3-5mm, and the width is 50-70mm. The fiber paper is pasted into the groove with high-temperature adhesive, completely covering the inner surface of the mounting groove, and the edge is flush with the opening of the mounting groove. The depth of the mounting groove can be 4-5mm.

[0071] During operation, the mounting groove provides positioning space for the fiber paper, which is then fixed in place after the adhesive cures. As the steel pipe 2 rotates, the fiber paper insulates against heat transfer to the sleeve 1.

[0072] Fiber paper is pasted between the blocking plate 5 and the end plate 6. The thickness of the fiber paper can be selected from 3-5mm, and it is ring-shaped with its inner and outer diameters matching those of the blocking plate 5 and the end plate 6, respectively. The fiber paper is sandwiched between the contact surfaces of the blocking plate 5 and the end plate 6 and is secured and tightened by bolts on the blocking plate 5 and the end plate 6.

[0073] During operation, fiber paper fills the gap between the blocking plate 5 and the end plate 6 to reduce the heat transferred to the end plate 6.

[0074] Multiple T-shaped pressure plates 9 are evenly spaced along the circumference of the sleeve 1; the middle of the pressure plate 9 is inserted into the mounting groove and presses the fiber paper, and the two sides abut against the groove wall; the pressure plate 9 and the sleeve 1 are fixed by bolts.

[0075] The number of pressure plates 9 can be selected from 4 to 6. The width of the middle part of the pressure plate 9 matches the width of the mounting groove (e.g., 50-70mm), and the width of the side flanges is 10-15mm. The pressure plates 9 can be made of 310S stainless steel; the fixing bolts 81 can be made of M6 hex socket head cap screws. The pressure plates 9 are tightened by bolts to evenly press the fiber paper into the mounting groove. When the steel pipe 2 rotates, the mechanical locking of the T-shaped pressure plates 9 and the even pressure of the bolts prevent the fiber paper from shifting or falling off.

[0076] The pressure plate 9 only contacts the mounting groove and does not contact the surface of the steel pipe 2. The gap between the pressure plate 9 and the inner wall of the steel pipe 2 is 1-2mm. The gap prevents the pressure plate 9 from directly conducting heat to the steel pipe 2, while allowing for thermal expansion and deformation. The pressure plate 9 only applies radial pressure to fix the fiber paper and does not participate in axial sealing.

[0077] This solution addresses the issue of fiber paper detachment at high temperatures by fixing the fiber paper in the mounting groove and T-shaped pressure plate 9; the fiber paper between the blocking plate 5 and the end plate 6 reduces heat transfer and the risk of cracking; the gap design of the pressure plate 9 further reduces heat conduction. Overall, this improves the reliability of the sealing device in high-temperature environments.

[0078] In another embodiment, the sealing device used in the coating process of the composite steel pipe 2 uses fiber paper with a maximum heat resistance temperature of 1400℃. Ceramic fiber paper can be selected, with a temperature resistance range typically between 1260-1400℃, ensuring normal operation of the fiber paper in high-temperature environments. Due to its particularly low thermal conductivity, it significantly reduces heat transfer during the combustion of the metal composite powder, keeping the outer surface of the sleeve 1 within a lower temperature range. Production operators can directly disassemble the device simply by wearing heat-resistant gloves. The fiber paper is adhered to the inner surface of the sleeve 1 using high-temperature resistant industrial adhesive (450℃ resistance).

[0079] In another embodiment, in the sealing device used for the coating process of the composite steel pipe 2, there are two pairs of connecting plates 4, and the two pairs of connecting plates 4 are symmetrically arranged on the sleeve 1. In any pair of first plates 41, only one first plate 41 is provided with a fixing hole 412.

[0080] In another embodiment, the elastic element 12 in the sealing device used for the coating process of the composite steel pipe 2 is a spring.

[0081] In another embodiment, the sealing device used in the coating process of the composite steel pipe 2 has a gap between the pressure plate 9 and the steel pipe 2. The inner diameter of the pressure plate 9 is slightly larger than the outer diameter of the steel pipe 2 to create a gap between them. This not only allows the sealing device to be easily fitted onto the steel pipe 2, reducing the heat transferred to the fiber paper, but also prevents the fiber paper from being scratched by the steel pipe 2.

[0082] In another embodiment, in the sealing device for the coating process of the composite steel pipe 2, a plurality of positioning bolts 10 are spaced apart along the circumferential direction on the sleeve 1, and a plurality of limiting bolts 11 are spaced apart along the circumferential direction. Each positioning bolt 10 is a stainless steel fine-thread set bolt and abuts against the steel pipe 2, fixing the sleeve 1 to the steel pipe 2. Each limiting bolt 11 is located on the outside of the end plate 6 and abuts against the end plate 6, used to limit the position of the end plate 6 and prevent the end plate 6 from axially displacing or falling off.

[0083] During installation, rotate the positioning bolt 10 so that its end presses against the outer wall of the steel pipe 2. The sleeve 1 is radially constrained by the positioning bolt 10 and remains coaxially fixed with the steel pipe 2. When the steel pipe 2 rotates at high speed, the positioning bolt 10 prevents the sleeve 1 from axially displacing through static friction.

[0084] During installation, screw in the limiting bolt 11 until the front end lightly touches the outside of the end plate 6. When the steel pipe 2 expands due to heat, the end plate 6 may move axially. The limiting bolt 11 restricts its displacement stroke by physically blocking it. The limiting bolt 11 restricts the axial movement of the end plate 6 under thermal expansion or vibration, preventing the sealing of the plug plate 5 from failing.

[0085] During operation, the internal temperature of steel pipe 2 rises to 1500℃ during coating, and end plate 6 may expand outwards from sleeve 1 due to the heat. Limiting bolt 11 absorbs axial displacement through rigid blocking, ensuring that end plate 6 remains pressed against plug plate 5. Without this limiting structure, end plate 6 may detach from sleeve 1, leading to liquid metal leakage.

[0086] Effect: The locating bolts 10 and the limiting bolts 11 work together to maintain the stable position of the sleeve 1 and the end plate 6 under the high-speed rotation and high-temperature thermal expansion of the steel pipe 2. The locating bolts 10 inhibit the radial displacement of the sleeve 1, and the limiting bolts 11 prevent the axial movement of the end plate 6, thus jointly solving the risk of material leakage caused by device dislocation.

[0087] In another embodiment, in the sealing device for the coating process of the composite steel pipe 2, each pair of eccentric blocks 8 are respectively arranged at both ends of the corresponding rotating shaft 7, each pair of first plates 41 are respectively arranged between the corresponding pair of eccentric blocks 8, and the two ends of the spring are respectively fixed to the middle of the corresponding extension plate 61 and the rotating shaft 7.

[0088] In another embodiment, in the sealing device for the coating process of the composite steel pipe 2, each rotating shaft 7 is provided with a handle 13. The handle 13 is U-shaped, and the two ends of the handle 13 are fixedly connected to the two ends of the rotating shaft 7 respectively. When the handle 13 is rotated toward the side where the spring is located, the spring is stretched.

[0089] In another embodiment, in the sealing device used for the coating process of the composite steel pipe 2, both the end plate 6 and the plug plate 5 are annular, with the inner diameter of the plug plate 5 being smaller than that of the end plate 6. The center of both the end plate 6 and the plug plate 5 serves as the channel for the ignition lead of the metal composite powder. Both the end plate 6 and the plug plate 5 are concentric annular structures, with the inner diameter of the plug plate 5 being smaller than that of the end plate 6. When they are coaxially assembled, the central through hole forms the through-channel for the ignition lead of the metal composite powder. The plug plate 5 directly provides the axial sealing function at the end of the steel pipe 2, while the end plate 6 is connected to the plug plate 5 by bolts to achieve the positioning and fixation of the plug plate 5. Increasing the inner diameter of the end plate 6 reduces the amount of material used while ensuring structural strength.

[0090] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A sealing device for the coating process of composite steel pipes, characterized in that, include: A sleeve, one end of which is fitted and fixed to the outside of a steel pipe, and the other end extending to the outside of the end of the steel pipe, and having multiple openings thereon, is coaxially arranged with the steel pipe. The inner wall of the sleeve is provided with a heat insulation layer, and the outer wall is fixed with multiple pairs of connecting plates. Each connecting plate is L-shaped and consists of a first plate and a second plate. Each first plate is parallel to the axis of the sleeve and has an opening extending along the axis of the sleeve. In any pair of first plates, at least one first plate has a fixing hole. A blocking plate is attached to the end of the steel pipe and located inside the sleeve; The end plate is fixedly connected to the blocking plate and is located inside the sleeve and outside the blocking plate. The end plate is provided with multiple extension plates, and the extension plates, openings and connecting plates correspond one-to-one and extend to the outside of the sleeve after passing through their corresponding openings. Each second plate is close to its corresponding extension plate. Multiple shafts, with one shaft inserted through each pair of openings; Multiple pairs of eccentric blocks are provided. Each pair of eccentric blocks is fixed on a rotating shaft. Each pair of eccentric blocks is opposite to a pair of second plates. The center of each eccentric block does not coincide with the axis of the rotating shaft. Fixing bolts are respectively installed on the eccentric blocks corresponding to the first plates with fixing holes. Multiple elastic elements, with each elastic element, extension plate, and rotating shaft corresponding to one another. The two ends of each elastic element are fixed to the corresponding extension plate and rotating shaft, respectively. In this configuration, for any given shaft, when the shaft rotates, a pair of eccentric blocks corresponding to it press against a pair of second plates corresponding to it, causing the shaft to move away from the corresponding extension plate in a pair of corresponding openings and stretching the elastic element until the fixing bolt and the corresponding fixing hole are aligned; when the fixing bolt is screwed into the corresponding fixing hole, the shaft is fixed on a pair of first plates; channels are provided on the end plate and the end plate.

2. The sealing device for the coating process of composite steel pipes as described in claim 1, characterized in that, The inner wall of the sleeve is provided with an annular mounting groove along its circumferential direction. The part of the sleeve located in the mounting groove is covered with a heat insulation layer, which is made of fiber paper. Fiber paper is also pasted between the end plate and the end plate. The sealing device used in the coating process of composite steel pipes also includes: Multiple pressure plates are evenly spaced along the circumferential direction of the sleeve. Each pressure plate is T-shaped. The protrusion in the middle of each pressure plate is inserted into the mounting groove and presses the fiber paper. The two sides abut against the two sides of the mounting groove. The side of each pressure plate opposite to the steel pipe is arc-shaped. The pressure plates and the sleeve are fixed by bolts passing through them.

3. The sealing device for the coating process of composite steel pipes as described in claim 1, characterized in that, The maximum heat resistance temperature of fiber paper is 1400℃.

4. The sealing device for the coating process of composite steel pipes as described in claim 1, characterized in that, There are two pairs of connecting plates, which are symmetrically arranged on the sleeve. In any pair of first plates, only one first plate has a fixing hole.

5. The sealing device for the coating process of composite steel pipes as described in claim 1, characterized in that, The elastic element is a spring.

6. The sealing device for the coating process of composite steel pipes as described in claim 2, characterized in that, There is a gap between the pressure plate and the steel pipe.

7. The sealing device for the coating process of composite steel pipes as described in claim 1, characterized in that, The sleeve is provided with multiple positioning bolts and multiple limiting bolts at intervals along its circumferential direction. Each positioning bolt abuts against the steel pipe and fixes the sleeve to the steel pipe. Each limiting bolt is located on the outside of the end plate and abuts against the end plate.

8. The sealing device for the coating process of composite steel pipes as described in claim 5, characterized in that, Each pair of eccentric blocks is respectively set at both ends of the corresponding rotating shaft, each pair of first plates is respectively set between the corresponding pair of eccentric blocks, and the two ends of the spring are respectively fixed to the middle of the corresponding extension plate and the rotating shaft.

9. The sealing device for the coating process of composite steel pipes as described in claim 5, characterized in that, Each shaft is equipped with a corresponding handle, which is U-shaped. The two ends of the handle are fixedly connected to the two ends of the shaft. When the handle is rotated toward the side where the spring is located, the spring is stretched.

10. The sealing device for the coating process of composite steel pipes as described in claim 1, characterized in that, Both the end plate and the blocking plate are annular, and the inner diameter of the blocking plate is smaller than the inner diameter of the end plate.

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