A thick-walled heat exchange tube bending device

Abstract

The application relates to the field of pipe bending forming, and particularly discloses a thick-wall heat exchange pipe bending device, which comprises a machine body and a moving table arranged on the machine body, a hollow chuck is arranged on the moving table, two plug plates matched with pipe insertion are arranged on the moving table, a sand injection pipe penetrating through the hollow chuck is arranged on the moving table, a sand source is connected to the sand injection pipe, a moving piece for driving the sand injection pipe to move is arranged on the moving table, a plug hole matched with the sand injection pipe is arranged on the plug plate away from one end of the pipe, a sand leakage mechanism is arranged in the hollow chuck, and a moving mechanism for controlling the movement of the plug plate is arranged on the machine body. The application has the effects of no manual sand filling, reduced manual intervention and improved operation efficiency.

Description

Technical Field

[0001] This application relates to the field of pipe bending and forming, and in particular to a thick-walled heat exchanger tube bending device. Background Technology

[0002] A heat exchanger tube is a tubular element installed inside a heat exchanger to transfer heat from one fluid to another. A tube bending machine is the equipment used in the entire tube bending process.

[0003] During the bending process of pipes, wrinkles and cross-sectional deformation are prone to occur at the inner bend. Existing technologies often employ mandrel bending and sand-filling bending to improve the bending quality. Mandrel bending involves sending a rigid mandrel, matching the inner diameter of the pipe, to the bending section to provide rigid support for the pipe wall. Sand-filling bending, a traditional auxiliary bending process still widely used today, involves filling the pipe with dry, clean sand particles. The "inner mold" formed by the filled sand particles resists the compression and extrusion forces generated during bending, thus preventing pipe wall collapse and excessive deformation. For thin-walled, medium-thick-walled, small-to-medium diameter, and round pipes, the more efficient and precise mandrel bending method is generally used. For medium-thick-walled, thick-walled, medium-to-large diameter, and complex pipe shapes, the sand-filling bending method can be used. For example, the more versatile sand-filling bending method is more suitable for bending thick-walled square pipes, especially when bending at multiple angles.

[0004] Regarding the aforementioned technologies, the inventors believe they have the following drawbacks: When using the sand-filling bending method, one end of the pipe must first be manually sealed with a plug to keep the pipe vertical. Then, sand must be filled into the pipe and sealed before it can be placed on the bending machine for bending. After bending, the plug must be manually removed to clean the sand from the pipe. The operation process has a low degree of automation and results in many wrinkles on the pipe surface. When bending thick-walled square pipes at multiple angles, the conventional sand-filling bending method has low efficiency in sand filling and cleaning, and results in many wrinkles on the pipe surface. Furthermore, the mandrel bending method requires multiple removals of the pipe for position adjustment due to the limitations of the mandrel's length and angle, making the operation quite complex. Summary of the Invention

[0005] In order to improve the problems of low automation and many wrinkles on the pipe surface when bending pipes using the sand-filling bending method, this application provides a thick-walled heat exchanger tube bending device.

[0006] The thick-walled heat exchanger tube bending device provided in this application adopts the following technical solution: A thick-walled heat exchanger tube bending device includes a body and a movable platform mounted on the body. A hollow clamp is mounted on the movable platform, along with two plug plates adapted for insertion into the tube. A sand injection pipe, penetrating the hollow clamp, is mounted on the movable platform and connected to a sand supply source. A movable component for driving the sand injection pipe is also mounted on the movable platform. An insertion hole adapted to the sand injection pipe is provided on the plug plate located at the end furthest from the tube. A sand leakage mechanism is installed inside the hollow clamp, and a movable mechanism for controlling the movement of the plug plates is mounted on the body.

[0007] Optionally, the moving mechanism includes a pressure-resistant rigid tube slidably disposed on the machine body, a control tube connected to the pressure-resistant rigid tube, a sand layer filled in the control tube, and a support tube passing through the hollow clamp. The pressure-resistant rigid tube is connected to an air source. The pressure-resistant rigid tube passes through the support tube. The inner diameter of the tube is equal to that of the support tube and the two are pressed together. One end of the control tube is fixedly connected to a blocking plate near one end of the hollow clamp, and the other end passes through a blocking plate away from the hollow clamp.

[0008] Optionally, the control tube includes a wear-resistant layer, an air-barrier layer, and a filter plate. The wear-resistant layer is wrapped around the inner and outer sides of the air-barrier layer, and the filter plate is located at one end close to the pressure-resistant rigid tube.

[0009] Optionally, multiple partitions are passed through and fixed to the control tube. The partitions are located between two of the blocking plates. The partitions are also provided with the insertion holes. The support tube is provided with a distance control device for controlling the distance between two adjacent partitions and between adjacent partitions and the blocking plates. When the blocking plates are not subjected to the tension of the pressure-resistant hard tube, the control tube is in a bent state.

[0010] Optionally, the distance control element is a plurality of tension springs connected between adjacent partitions and between adjacent partitions and the blocking plate.

[0011] Optionally, a vibration motor is provided on the moving platform, and the output end of the vibration motor acts on the pipe.

[0012] Optionally, the sand leakage mechanism includes a sand leakage port located below the support pipe and a sand storage hopper disposed within the machine body. The sand leakage port is connected to the sand storage hopper, and the sand storage hopper is also connected to the sand injection pipe.

[0013] Optionally, a locking block is provided at the end of the pipe away from the hollow clamp, and the locking block abuts against the blocking plate at the end away from the hollow clamp.

[0014] In summary, this application includes at least one of the following beneficial technical effects: 1. A sealed space is formed inside the pipe by using a blocking plate. The sand injection pipe fills the pipe with fine sand to form an "inner mold". Then the pipe can be bent. The sand injection process is highly automated, requiring no manual sand injection and is highly efficient. 2. When the blocking plate needs to be moved to the designated position on the pipe, the air source first evacuates the control tube through the pressure-resistant rigid pipe. At this time, the sand layer inside the control tube hardens due to the pressure difference between the inside and outside of the control tube. The hardened control tube is then propelled forward by the friction wheel, thereby moving the blocking plate to the corresponding position. At this point, the clamp is placed at one end of the pipe, so that the clamp and the blocking plate are tightly pressed together. When the pipe needs to be bent after sand filling, the air source injects a small amount of gas into the control tube, thereby making the control tube in a shape that can be deformed at will. This avoids the control tube being too hard and affecting the bending operation of the pipe, and also avoids the difficulty of pulling the blocking plate to remove sand in the bent pipe. In other words, the control tube with controllable hardness is easy to push the blocking plate without interfering with the bending operation of the pipe, and also makes it easy to pull out the blocking plate and fine sand from the bent pipe. 3. When the pipe needs to be cleaned after bending, the control pipe in the softer state is straightened in sequence and the blocking plate, partition plate and blocking plate are pulled from the end near the pressure-resistant rigid pipe to the end away from the pressure-resistant rigid pipe. This straightens the control pipe of each cavity in sequence, thus removing the fine sand in each cavity of the pipe in batches. This facilitates the smooth removal of fine sand from the pipe and avoids the blockage plate farthest from the pressure-resistant rigid pipe from being stuck due to a large amount of fine sand and the bent pipe, which would prevent the sand from being cleaned smoothly. 4. After the control tube is completely removed from the pipe and is in a soft state, the tension spring pulls the partition and / or the blocking plate to move relative to each other, so that the control tube is in a drooping state. This makes it easy for the control tube to remain in a drooping state when the blocking plate and partition are put into the pipe next time. At the same time, the interaction of multiple tension springs also keeps the partition and the blocking plate in an upright state, preventing the partition and the blocking plate from tipping over when the control tube is in a soft state. 5. During pipe bending operations, in addition to being fixed externally by the threaded ear plates, the anti-wrinkle plate is also fixed by the mounting blocks and mounting grooves to improve the stability of the anti-wrinkle plate's working surface and further reduce the generation of internal bends in the pipe. This fixing method does not require additional holes to be drilled on the working surface of the anti-wrinkle plate for threaded fixing, avoiding the impact of holes on the working surface of the anti-wrinkle plate on the pipe. Moreover, the fixing method of the mounting blocks and mounting grooves becomes more and more stable as the pipe is fed. At the same time, the installation method of the anti-wrinkle plate is simple and easy to maintain. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application; Figure 2 This application is used to illustrate the cross-sectional structural diagram of the hollow clamp, temporary storage hopper, screw conveyor, sand leakage mechanism, pressure-resistant rigid pipe and support pipe; Figure 3 This application is used to show the cross-sectional structural diagram of the hollow clamp, partition, tension spring, sand injection pipe, secondary sand discharge port, sand leakage port, moving mechanism, clamping block and pipe; Figure 4 This application is a schematic diagram illustrating the structure of the temporary storage hopper, sandblasting hose, screw conveyor, and friction wheel. Figure 5 This application is a structural schematic diagram illustrating the bending die, clamping die, auxiliary pushing die, anti-wrinkle die, and anti-wrinkle plate; Figure 6 This is a cross-sectional structural diagram used in this application to illustrate the anti-wrinkle mold, anti-wrinkle plate, and mounting components.

[0016] Reference numerals: 1. Machine body; 11. Moving platform; 12. Hollow chuck; 13. Bending mold; 14. Clamping mold; 15. Auxiliary pushing mold; 16. Anti-wrinkle mold; 161. Anti-wrinkle plate; 21. Blocking plate; 211. Insertion hole; 22. Partition plate; 221. Tension spring; 3. Sand injection pipe; 31. Secondary sand discharge port; 32. Temporary storage hopper; 33. Sandblasting hose; 34. Screw conveyor; 4. Sand leakage mechanism; 41. Sand leakage port; 42. Sand storage hopper; 5. Moving mechanism; 51. Pressure-resistant rigid pipe; 52. Control pipe; 53. Sand layer; 54. Support pipe; 6. Vibration motor; 7. Friction wheel; 81. Pipe; 82. Clamping block; 9. Mounting assembly; 91. Mounting groove; 92. Mounting block; 93. Ear plate; Detailed Implementation

[0017] The following is in conjunction with the appendix Figures 1-6 This application will be described in further detail.

[0018] This application discloses a thick-walled heat exchanger tube bending device. (Refer to...) Figures 1-6The thick-walled heat exchanger tube bending device includes a body 1, a bending die 13, a clamping die 14, an auxiliary pushing die 15, an anti-wrinkle die 16, and a moving platform 11 mounted on the body 1. The moving platform 11 is equipped with hollow clamps 12, which can be either pneumatic or hydraulic. The moving platform 11 has two plug plates 21 that are compatible with the tube 81 for insertion. A sand injection pipe 3 penetrates the hollow clamp 12 and is connected to a sand source. The moving platform 11 also has a moving component for driving the sand injection pipe 3. Two friction wheels 7 are driven and pressed against both sides of the sand injection pipe 3. When the sand injection pipe 3 extends into the pipe 81, the sand injection pipe 3 abuts against the top of the pipe 81. The plug plate 21 located at the end away from the pipe 81 has an insertion hole 211 adapted to the sand injection pipe 3. The hollow clamp 12 is equipped with a sand leakage mechanism 4. The machine body 1 is equipped with a moving mechanism 5 for controlling the movement of the plug plate 21. The anti-wrinkle mold 16 is equipped with an anti-wrinkle plate 161 on the side near the pipe. The anti-wrinkle plate 161 is made of copper. The anti-wrinkle mold 16 is equipped with an installation component 9 for installing the anti-wrinkle plate.

[0019] The pipe 81 is placed on the machine body 1, and the auxiliary push mold 15 and anti-wrinkle mold 16, bending mold 13 and clamping mold 14 clamp one end of the pipe 81. The other end of the pipe 81 is clamped and fixed by the hollow clamp 12. The moving mechanism 5 drives the two blocking plates 21 to seal both ends of the pipe 81 respectively. Then, the moving part causes the sand injection pipe 3 to be inserted into the cavity between the two blocking plates 21 inside the pipe 81 through the insertion hole 211. First, the sand injection pipe 3 is placed at the end of the pipe 81 closest to the hollow clamp 12 and continuously injects sand until the sand injection pipe 3 can no longer inject sand. Then, the sand injection pipe 3 is slowly moved from the end away from the hollow clamp 12 to the end closer to the hollow clamp 12 while injecting sand, so that the inside of the pipe 81 is filled with sand to form an "inner mold". At this point, the pipe 81 can be bent by the machine body 1. Specifically, the bending mold 13 rotates, and the clamping mold 14 revolves around the bending mold 13. During this process, the auxiliary pushing mold 15 pushes the pipe 81 forward synchronously to reduce the tensile force on the outer bend of the pipe 81 and prevent the outer bend of the pipe 81 from being stretched too thin or even broken. The anti-wrinkle plate 161 provides support near the inner bend of the pipe 81 to further reduce the wrinkles at the inner bend of the pipe 81. After the pipe 81 is bent, the two blocking plates 21 are moved by the moving mechanism 5. The blocking plate 21 located at the end away from the hollow clamp 12 will also push the sand particles out of the pipe 81 and drain the sand through the sand leakage mechanism 4 to complete the sand cleaning operation of the pipe 81. The whole process has less manual intervention, higher efficiency, and lower labor costs.

[0020] Reference Figure 1 , Figure 3 and Figure 4The moving mechanism 5 includes a pressure-resistant hard tube 51 slidably mounted on the body 1, a control tube 52 connected to the pressure-resistant hard tube 51, a sand layer 53 filled in the control tube 52, and a support tube 54 passing through the hollow clamp 12. The pressure-resistant hard tube 51 is connected to an air source, which can be a vacuum pump that can pump and vent air, connected to the pressure-resistant hard tube 51. The movement of the pressure-resistant hard tube 51 is also carried out by the friction wheel 7. That is, friction is also provided on the two opposite sides of the pressure-resistant hard tube 51 on the moving table 11. The pressure-resistant hard tube 51 passes through the support tube 54. The inner diameter of the tube 81 and the support tube 54 are equal and they are pressed together. One end of the control tube 52 is fixedly connected to the end plate 21 near the hollow clamp 12, and the other end passes through the end plate 21 away from the hollow clamp 12. The control tube 52 includes a wear-resistant layer, an air-barrier layer, and a filter plate. The wear-resistant layer is wrapped around the inner and outer sides of the air-barrier layer. The filter plate is located at the end closest to the pressure-resistant rigid tube 51. The wear-resistant layer is made of PP synthetic fiber cloth, and the inner layer is a polypropylene coating to improve the tensile and puncture resistance of the control tube 52 and prevent fine sand penetration. The filter plate prevents sand particles from being drawn into the sand layer 53 when the air source is pumped out. A locking block 82 is also provided at the end of the tube 81 away from the hollow clamp 12, and the locking block 82 abuts against the blocking plate 21 at the end away from the hollow clamp 12. The locking block 82 can be made of readily available materials such as a rag or a special hard rubber stopper that is interference-fitted with the tube 81.

[0021] When the blocking plate 21 needs to be moved to the designated position of the pipe 81, the air source first evacuates the control pipe 52 through the pressure-resistant hard pipe 51. At this time, the sand layer 53 inside the control pipe 52 hardens due to the pressure difference between the inside and outside of the control pipe 52. Specifically, the sand particles in the sand layer 53 are tightly squeezed together due to the pressure difference, and they fill, fit and rub against each other to the maximum extent. In addition to the pressure difference, the hardness of the control pipe 52 is also related to the shape and size of the sand particles. The smaller and more uneven the size of the sand particles and the more irregular the shape, the higher the hardness of the control pipe 52. The hardened control pipe 52 is then conveyed forward by the friction wheel 7, which moves the blocking plate 21 to the corresponding position. At this time, the clamping block 82 is blocked at one end of the pipe 81, so that the clamping block 82 and the blocking plate 21 are pressed tightly together. When the sand filling is completed and the pipe 81 needs to be bent, the air source fills a small amount of gas into the control pipe 52, so that the control pipe 52 is in a deformable state, so as to avoid the influence of the overly rigid control pipe 52 on the bending operation of the pipe 81, and also to avoid the difficulty of pulling the blocking plate 21 to clean the sand in the bent pipe 81 when the overly rigid control pipe 52 is too hard; during the bending operation, the clamp 82 also prevents the blocking plate 21 from falling out of the pipe 81.

[0022] In some implementations, the blocking plate 21 is directly eliminated, making the outer diameter of the control tube 52 equal to the inner diameter of the pipe 81. That is, the pipe 81 is directly supported by the control tube 52 and the sand particles inside the control tube 52. This solution seems to be simpler to operate, simpler in structure, and more effective. However, this solution is not suitable for practical applications. The main reason is that the control tube 52 is in direct contact with the inner wall of the pipe 81, but the prefabricated control tube 52 itself cannot perfectly fit the inner wall of each pipe 81, especially square tubes and other irregular or complex shaped pipes 81. This results in many tiny gaps between the control tube 52 and the pipe 81. During bending operations, these tiny gaps become the starting points for the collapse of the pipe 81 wall, resulting in poor support. Furthermore, if the control tube 52 is plugged into or press-fitted into the tube 81, the control tube 52 will be difficult to insert into the tube 81. At the same time, even if the tube 81 is made of a material with poor elasticity, slight elastic deformation or wrinkling will still occur, further affecting the support effect on the tube 81. Its actual effect is even lower than that of the rubber core rod.

[0023] This application first places the finer control tube 52 in a vacuum state filled with sand, at which point the control tube 52 can hardly expand or contract. Then, sand is directly injected into the pipe 81. Since the fine sand is in direct contact with the inner wall of the pipe 81, it is equivalent to an "inner mold" that can transmit uniform and rigid pressure. The fine sand particles squeeze, rub, and lock against each other, forming a nearly incompressible whole. When the pipe wall is bent, it squeezes the fine sand inward, and the fine sand transmits the pressure in all directions, thereby uniformly supporting the pipe wall in the bent area from the inside.

[0024] Reference Figure 2 and Figure 3 Multiple baffles 22 are connected and fixed to the control pipe 52. The baffles 22 are located between two blocking plates 21. The baffles 22 are also provided with insertion holes 211. The baffles 22 are fixed to the control pipe 52. The support pipe 54 is provided with a distance control device for controlling the distance between two adjacent baffles 22 and between adjacent baffles 22 and blocking plates 21. When the blocking plate 21 is not subjected to the tension of the pressure-resistant hard pipe 51, the control pipe 52 is in a bent state. The side wall of the sand injection pipe 3 is also provided with a secondary sand discharge port 31 near the top. The moving table 11 is fixed with a vibration motor 6. The output end of the vibration motor 6 acts on the pipe 81.

[0025] The partition plate 22 and the blocking plate 21 divide the pipe 81 into multiple cavities. When sand needs to be injected into the pipe 81, the opening of the sand injection pipe 3 at the end away from the hollow clamp 12 and the secondary sand discharge port 31 are inserted into the cavity farthest from the hollow clamp 12. This cavity is called the first cavity. Then, fine sand is injected into the first cavity from the opening of the sand injection pipe 3 and the secondary sand discharge port 31. When the sand injection pipe 3 can no longer inject sand into the first cavity, the first cavity has been filled with fine sand. Then, the sand injection pipe 3 is gradually withdrawn until the outlet of the sand injection pipe 3 is still in the first cavity, while the secondary sand discharge port 31 is located in the cavity adjacent to the first cavity. The cavity adjacent to the first cavity is called the second cavity. Since the sand injection pipe 3 continues to supply sand but the first cavity is full, fine sand leaks out from the secondary sand discharge port 31. When the second cavity is filled, the sand injection pipe 3 is gradually withdrawn again while always supplying sand. This avoids the situation where the sand injection pipe 3 is directly withdrawn from the previously filled cavity, and the cavity that was originally filled with fine sand leaks sand at the insertion hole 211 into the adjacent cavity that is not filled with fine sand, causing the cavity to not be filled. When the secondary sand discharge port 31 moves to the cavity near the end of the hollow clamp 12, the sand injection pipe 3 stops moving. That is, the plug plate 21, the sand injection pipe 3, and the fine sand in the sand injection pipe 3 seamlessly seal one end of the pipe 81. Furthermore, throughout the entire sand injection process, the vibrating motor 6 continuously acts on the pipe 81 with small amplitude and high frequency vibration, which, together with the sand injection pipe 3, injects sand into each small cavity at a certain pressure, further improving the degree of filling of the cavity by fine sand.

[0026] When the pipe 81 is bent and sand needs to be removed, the control pipe 52 in its softer state is straightened in sequence and pulled from the end near the pressure-resistant hard pipe 51 to the end away from the pressure-resistant hard pipe 51. This straightens the control pipe 52 of each cavity in sequence, thus removing the fine sand in each cavity of the pipe 81 in batches. This facilitates the smooth removal of fine sand from the pipe 81 and avoids the blockage plate 21, which is furthest from the pressure-resistant hard pipe 51, from being stuck due to a large amount of fine sand and the bent pipe 81 when the blockage plate 21 is pulled directly, preventing the sand from being removed smoothly.

[0027] Reference Figure 3The distance control device consists of multiple tension springs 221 connected between adjacent partitions 22 and between adjacent partitions 22 and blocking plates 21. The specific connection points of the tension springs 221 are around the partitions 22 and / or blocking plates 21, with no fewer than two tension springs 221 arranged symmetrically. After sand removal is completed, the control pipe 52 is completely withdrawn from the pipe 81 and is in a soft state. The tension springs 221 pull the partitions 22 and / or blocking plates 21 to move relative to each other, causing the control pipe 52 to hang down. At the same time, the interaction of multiple tension springs 221 also keeps the partitions 22 and blocking plates 21 in an upright state, preventing the partitions 22 and blocking plates 21 from tipping over when the control pipe 52 is in a soft state. In other feasible embodiments, the distance control element may also be a magnet embedded in the support tube 54 at intervals. Magnets are also embedded in the partition 22 and the blocking plate 21. The magnets in the support tube 54 are arranged with their positive and negative poles alternating. The magnets between the partitions 22 and between the partitions 22 and the blocking plate 21 are also arranged with their positive and negative poles alternating. Thus, when the control tube 52 is in a soft state and withdraws from the tube 81, the magnets in the support tube 54 will attract the partitions 22 and the blocking plate 21 to the designated position.

[0028] Reference Figure 1 and Figure 2 The sand leakage mechanism 4 includes a sand leakage port 41 located below the support pipe 54 and a sand storage hopper 42 located inside the machine body 1. The support pipe 54 has the same inner diameter as the pipe 81. The sand leakage port 41 is connected to the sand storage hopper 42, and the sand storage hopper 42 is also connected to the sand injection pipe 3. The fine sand supply method in the sand injection pipe 3 is as follows: the sand supply source of the sand injection pipe 3 is a temporary storage hopper 32 connected to the sand injection pipe 3. The temporary storage hopper 32 is connected to a sandblasting hose 33. The suction end of the sandblasting hose 33 extends into the sand storage hopper 42. The sandblasting hose 33 is also connected to an air pipe or air pump. That is, the sandblasting hose 33 is actually a Venturi tube, which transports the fine sand in the sand storage hopper 42 to the temporary storage hopper 32 for temporary storage through the Venturi effect. This principle is similar to that of the existing suction sandblasting machine, and will not be elaborated on here. The temporary storage hopper 32 is also provided with an air outlet sealed by a filter plate, which facilitates the flow of gas in the temporary storage hopper 32 while preventing fine sand from being sprayed out from the air outlet. A small screw conveyor 34 of a certain length is also provided in the sand injection pipe 3 to send the fine sand in the temporary storage hopper 32 to the outlet end of the sand injection pipe 3.

[0029] As the control pipe 52 pulls the blocking plate 21 and partition plate 22 to gradually retract, the fine sand in each cavity enters the support pipe 54 through the pipe 81, and finally enters the sand storage hopper 42 from the sand leakage port 41. When the sand injection pipe 3 needs to perform sand injection, the sandblasting hose 33 supplies the fine sand in the sand storage hopper 42 to the temporary storage hopper 32, while the screw conveyor 34 pushes the fine sand in the temporary storage hopper 32 towards the outlet end of the sand injection pipe 3. The reuse of fine sand reduces the frequency of manual sand replenishment to the sand storage hopper 42. At the same time, the screw conveyor 34 and the sand injection hose, together with the sand supply method of the temporary storage hopper 32, make the sand supply of the sand injection pipe 3 more stable and the sand injection efficiency higher.

[0030] Reference Figure 5 and Figure 6 The mounting assembly 9 includes several mounting slots 91 formed on the anti-wrinkle mold 16, mounting blocks 92 fixed to the anti-wrinkle plate 161, and ear plates 93 integrally formed on the edge of the anti-wrinkle plate 161. The mounting blocks 92 are inserted into and adapted to the mounting slots 91. One end of the mounting block 92 near the hollow clamp 12 is beveled, and the other end is straight. The ear plates 93 are threadedly connected to the anti-wrinkle mold 16 by screws. When it is necessary to replace the anti-wrinkle plate 161 with a new one or one with a different coefficient of friction, simply loosen the screws, pull out the anti-wrinkle plate 161 in the opposite direction of the pipe 81's advance, insert the new anti-wrinkle plate 161 into the anti-wrinkle mold 16, and retighten the screws.

[0031] During pipe bending operations, in addition to being externally fixed by the threaded ear plate 93, the anti-wrinkle plate 161 is also fixed by the mounting block 92 and the mounting groove 91 to improve the stability of the working surface of the anti-wrinkle plate 161. This fixing method eliminates the need for additional holes to be drilled on the working surface of the anti-wrinkle plate 161 for threaded fixing, avoiding any impact from holes on the working surface of the anti-wrinkle plate 161 on the pipe. Furthermore, the fixing method of the mounting block 92 and the mounting groove 91 becomes increasingly stable as the pipe 81 is fed. The installation method of the anti-wrinkle plate 161 is simple and easy to maintain. Countersunk screw holes can be made on the auxiliary push die 15 to fix sandpaper to the auxiliary push die 15 with countersunk screws, or sandpaper can be directly glued on to increase the friction coefficient of the auxiliary push die 15 and prevent relative sliding between the auxiliary push die 15 and the pipe 81.

[0032] The implementation principle of the thick-walled heat exchanger tube bending device in this application embodiment is as follows: Place the pipe 81 on the machine body 1 and clamp one end of the pipe 81 with the hollow clamp 12. The air source first evacuates the control pipe 52 through the pressure-resistant hard pipe 51. At this time, the sand layer 53 inside the control pipe 52 hardens due to the pressure difference between the inside and outside of the control pipe 52. The hardened control pipe 52 is then conveyed forward by the friction wheel 7, which in turn moves the blocking plate 21 and the partition plate 22 to the corresponding positions. At this time, the clamping block 82 is placed on one end of the pipe 81, so that the clamping block 82 and the blocking plate 21 are pressed tightly together. The partition plate 22 and the blocking plate 21 divide the pipe 81 into multiple cavities. When sand needs to be injected into the pipe 81, the vibrating motor 6 always acts on the pipe 81 with a small amplitude and high frequency. The opening of the sand injection pipe 3 away from the hollow clamp 12 and the secondary sand discharge port 31 are inserted into the first cavity. Then, fine sand is injected into the first cavity from the opening of the sand injection pipe 3 and the secondary sand discharge port 31. When the sand injection pipe 3 can no longer inject sand into the first cavity, the first cavity has been filled with fine sand. Then, the sand injection pipe 3 is gradually withdrawn until its outlet remains in the first cavity, while the secondary sand discharge port 31 is located in the second cavity. Since the sand injection pipe 3 continuously supplies sand but the first cavity is full, fine sand leaks out from the secondary sand discharge port 31. Once the second cavity is filled, the sand injection pipe 3 is gradually withdrawn again while continuing to supply sand. This prevents the sand injection pipe 3 from being directly withdrawn from the previously filled cavity, causing sand to leak from the previously filled cavity into the adjacent, unfilled cavity at the insertion hole 211, thus preventing the cavity from becoming completely unfilled. Furthermore, the entire sand injection process, coordinated with the sand injection pipe 3, injects sand into each small cavity at a certain pressure, further improving the filling degree of the cavities by the fine sand. When the sand filling is completed and the pipe 81 needs to be bent, a small amount of gas is injected into the control pipe 52, so that the control pipe 52 is in a deformable state. This avoids the control pipe 52 being too stiff and affecting the bending operation of the pipe 81, and also avoids the difficulty of pulling the blocking plate 21 to clean the sand in the bent pipe 81 when the control pipe 52 is too stiff. After the pipe 81 is bent, when it needs to be cleaned, the control pipe 52 in a softer state is straightened in sequence and pulled from the end near the pressure-resistant hard pipe 51 to the end away from the pressure-resistant hard pipe 51, the blocking plate 21, the partition plate 22, and the blocking plate 21. This straightens the control pipe 52 of each cavity in sequence, that is, the fine sand in each cavity of the pipe 81 is removed in batches. This makes it easier for the fine sand in the pipe 81 to be cleaned out smoothly. It avoids the large amount of fine sand and the bent pipe 81 causing the blocking plate 21, which is farthest from the pressure-resistant hard pipe 51, to get stuck and prevent smooth sand cleaning when the blocking plate 21 is pulled directly. The whole process has less manual intervention, higher efficiency, and lower labor costs.

[0033] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A thick-walled heat exchanger tube bending device, characterized in that: The device includes a body (1), a bending mold (13), a clamping mold (14), an auxiliary pushing mold (15), an anti-wrinkle mold (16), and a moving platform (11) mounted on the body (1). The moving platform (11) is equipped with a hollow clamp (12), and two plug plates (21) that are compatible with the pipe (81) for insertion. A sand injection pipe (3) penetrates the hollow clamp (12) and is connected to a sand source. The moving platform (11) is also equipped with a mechanism for driving the pipe. The moving part of the sand injection pipe (3) is provided with a plug plate (21) located at the end away from the pipe (81) and an insertion hole (211) adapted to the sand injection pipe (3). The hollow clamp (12) is provided with a sand leakage mechanism (4). The body (1) is provided with a moving mechanism (5) for controlling the movement of the plug plate (21). The anti-wrinkle mold (16) is provided with an anti-wrinkle plate (161) on the side close to the pipe (81). The anti-wrinkle mold (16) is provided with an installation component (9) for installing the anti-wrinkle plate (161). The moving mechanism (5) includes a pressure-resistant hard tube (51) slidably disposed on the body (1), a control tube (52) connected to the pressure-resistant hard tube (51), a sand layer (53) filled in the control tube (52), and a support tube (54) passing through the hollow clamp (12). The pressure-resistant hard tube (51) is connected to an air source. The pressure-resistant hard tube (51) passes through the support tube (54). The inner diameter of the tube (81) and the support tube (54) are equal and they are pressed together. One end of the control tube (52) is fixedly connected to a blocking plate (21) near one end of the hollow clamp (12), and the other end passes through a blocking plate (21) away from the hollow clamp (12). When the block (21) needs to be moved to the designated position of the pipe (81), the air source first evacuates the control pipe (52) through the pressure-resistant hard pipe (51). At this time, the sand layer (53) inside the control pipe (52) hardens due to the pressure difference inside and outside the control pipe (52). The hardened control tube (52) is then conveyed forward by the friction wheel (7), which in turn moves the block plate (21) to the corresponding position. The air source fills the control tube (52) with a small amount of gas, which in turn makes the control tube (52) in a deformable state. The sand leakage mechanism (4) includes a sand leakage port (41) opened below the support pipe (54) and a sand storage hopper (42) set in the body (1). The sand leakage port (41) is connected to the sand storage hopper (42), and the sand storage hopper (42) is also connected to the sand injection pipe (3).

2. The thick-walled heat exchanger tube bending device according to claim 1, characterized in that: The control tube (52) includes a wear-resistant layer, an air-barrier layer and a filter plate. The wear-resistant layer is wrapped around the inner and outer sides of the air-barrier layer, and the filter plate is located at one end close to the pressure-resistant hard tube (51).

3. The thick-walled heat exchanger tube bending device according to claim 1, characterized in that: Multiple partitions (22) are connected through and fixed to the control tube (52). The partitions (22) are located between two blocking plates (21). The partitions (22) are also provided with the insertion holes (211). The support tube (54) is provided with a distance control device for controlling the distance between two adjacent partitions (22) and between adjacent partitions (22) and blocking plates (21). When the blocking plate (21) is not subjected to the tension of the pressure-resistant hard tube (51), the control tube (52) is in a bent state.

4. The thick-walled heat exchanger tube bending device according to claim 3, characterized in that: The distance control element is a plurality of tension springs (221) connected between adjacent partitions (22) and between adjacent partitions (22) and the blocking plate (21).

5. The thick-walled heat exchanger tube bending device according to claim 1, characterized in that: The moving platform (11) is equipped with a vibration motor (6), and the output end of the vibration motor (6) acts on the pipe (81).

6. The thick-walled heat exchanger tube bending device according to claim 1, characterized in that: The end of the pipe (81) away from the hollow clamp (12) is also provided with a locking block (82), and the locking block (82) abuts against the blocking plate (21) at the end away from the hollow clamp (12).

7. The thick-walled heat exchanger tube bending device according to claim 1, characterized in that: The mounting assembly (9) includes several mounting slots (91) formed on the anti-wrinkle mold, mounting blocks (92) fixed to the anti-wrinkle plate (161), and ear plates (93) integrally formed on the edge of the anti-wrinkle plate. The mounting blocks (92) are inserted into and adapted to the mounting slots (91). One end of the mounting block (92) near the hollow clamp (12) is inclined and the other end is straight. The ear plates (93) are threaded to the anti-wrinkle mold (16).

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