A flangeless tube expanding machine and method for heat exchangers

Abstract

The application discloses a flange-free pipe expanding machine and method for heat exchangers, which comprises a stamping mechanism and a supporting tool, the supporting tool comprises a fixed seat, the upper side of the fixed seat is connected with a sliding plate through a slide rail, the upper side of the sliding plate is connected with a bottom plate, the upper side of the bottom plate is connected with a plurality of longitudinally arranged floating blocks, and the upper side of the bottom plate is also provided with supporting blocks; the stamping mechanism comprises a supporting frame, the supporting frame is connected with a stamping driving device, the driving end of the stamping driving device is connected with a lifting positioning plate, the lower side of the lifting positioning plate is connected with a plurality of stamping rods, and the lower end of the stamping rod is connected with a pipe expanding end; the floating blocks arranged on the bottom plate offset the downward pressure of the stamping rods on the cooling pipe during pipe expanding, so that the length of the upper end of the cooling pipe extending out of the tube plate after pipe expanding is sufficient and in a uniform alignment state, and the sealing property and corrosion resistance of the tube plate are ensured.

Description

Technical Field

[0001] This invention relates to the field of heat exchanger tube expansion equipment technology, specifically to a tube expansion machine and method for heat exchangers that does not require flanging. Background Technology

[0002] A heat exchanger (also known as a heat exchanger or heat exchange equipment) is a device used to transfer heat from a hot fluid to a cold fluid to meet specified process requirements. It is an industrial application of convective heat transfer and heat conduction.

[0003] Among them, the core assembly is an important heat exchange component, which generally includes a fixed tube sheet, cooling tube assembly and heat exchange fins. The effective interference fit between the fins and the cooling tubes is the key factor that determines the heat transfer efficiency of this type of product. The tube expander is a special equipment used to expand the cooling tubes and to make the cooling tubes and heat exchange fins interference fit.

[0004] During the tube expansion process, the diameter of the cooling tube becomes larger, allowing the cooling tube to make interference contact with the fins to ensure heat exchange efficiency. Due to material factors, the length of the cooling tube will become shorter, and the lower end of the cooling tube will be suspended. Under the downward pressure of the stamping rod, the cooling tube is prone to downward displacement, resulting in insufficient or inconsistent length of the upper end of the cooling tube extending out of the tube sheet, which affects the sealing and corrosion resistance of the tube sheet.

[0005] In existing technologies, plate-type coolers are usually manufactured manually. The tube ends are manually flanged and expanded, and then rolled and cut. Manual flanging is very labor-intensive, the force is difficult to control, it requires a high level of experience from the operator, and it is time-consuming. Moreover, the inconsistency in flanging of each tube opening also affects the tube expansion quality. There are instances where the cooling tube ends are pushed into the inner wall of the tube sheet. In addition, when cutting the tube end, the control of the tool and the force may damage the surface of the tube sheet, damaging the appearance or causing damage to the coating or plating, creating a risk of corrosion. Furthermore, burrs are also easily left at the tube openings, affecting the cleanliness of the product. Summary of the Invention

[0006] The purpose of this invention is to address the problems existing in the prior art by providing a heat exchanger tube expander and method without flanges. By setting floating blocks on the base plate, the downward pressure of the stamping rod on the cooling tube during tube expansion is offset, so that the cooling tube remains stationary during the tube expansion process. This ensures that the upper end of the cooling tube extends sufficiently beyond the tube sheet after tube expansion and is uniformly aligned, thus guaranteeing the sealing and corrosion resistance of the tube sheet. The invention features a high degree of automation and low cost.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A tube expander for heat exchangers without flanges, characterized in that it includes a stamping mechanism and a supporting fixture. The supporting fixture includes a fixed base, a sliding plate connected to the upper side of the fixed base via a slide rail, a base plate connected to the upper side of the sliding plate, a plurality of longitudinally parallel floating strips connected to the upper side of the base plate, and a support strip on the upper side of the base plate. The stamping mechanism includes a support frame connected to a stamping drive device, a lifting positioning plate connected to the drive end of the stamping drive device, a plurality of stamping rods connected to the lower side of the lifting positioning plate, and tube expander ends connected to the lower ends of the stamping rods.

[0009] The support blocks include a first support block and a second support block. The first support block and the second support block are symmetrically arranged at both ends of a plurality of floating blocks. The first support block and the second support block limit the plurality of floating blocks in the horizontal direction, so that the plurality of floating blocks are evenly spaced and parallel.

[0010] The floating block includes a strip plate and a plurality of springs, wherein the plurality of springs are disposed between the strip plate and the base plate;

[0011] Each of the strip plates has a plurality of first mounting slots on its lower end face, and the base plate has a number and position of corresponding second mounting slots on its upper end face. The upper end of the spring is engaged in the first mounting slot, and the lower end of the spring is engaged in the second mounting slot.

[0012] The first support block and the second support block are each provided with a plurality of vertical guide grooves. The vertical guide grooves on both sides are symmetrically arranged. Each end of the strip plate is connected to an insert block, which is inserted into the vertical guide groove.

[0013] Each of the vertical guide slots has a height limiting plate at its upper end, and the insert block is located between the height limiting plate and the bottom plate.

[0014] The lower side of the lifting positioning plate is provided with several threaded holes, and the upper end of the stamping rod is connected to the lifting positioning plate by a thread; the several stamping rods are arranged in one or two rows along the longitudinal direction, and the number of stamping rods in each row is set to 8 to 15.

[0015] The fixed base is connected to a linear displacement driving device, and the driving end of the linear displacement driving device is connected to the sliding plate.

[0016] The lower side of the lifting positioning plate is provided with several parallel auxiliary positioning plates, and the support frame is provided with several vertically arranged guide rods. The guide rods pass through the lifting positioning plate and several auxiliary positioning plates in sequence. The stamping rod passes through several auxiliary positioning plates in sequence.

[0017] A hinge connects each pair of adjacent auxiliary positioning plates, and a hinge also connects the uppermost auxiliary positioning plate to the lifting positioning plate.

[0018] A method for expanding a tube without flanging includes the following steps:

[0019] S1. Place one side tube sheet of the heat exchanger core assembly on the support bar of the support fixture, align the several rows of cooling tubes of the core assembly with the floating bar, and align the several stamping rods with the corresponding cooling tubes.

[0020] S2. The stamping drive device drives the stamping rod to move downward until the expanded end of the lower end of the stamping rod contacts the upper end of the cooling pipe.

[0021] S3. The stamping rod continues to move downward, causing the end of the expanding tube to squeeze the cooling tube, causing the entire cooling tube to move downward until the floating block in contact with the lower end of the cooling tube sinks to the limit position.

[0022] S4. The stamping rod continues to move downward, causing the expanding end to be squeezed into the cooling tube, expanding the cooling tube. During the expansion process, the length of the cooling tube becomes shorter, and the floating block rebounds, maintaining support for the cooling tube until the expanding end completely expands the cooling tube.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. By setting floating blocks on the base plate, the lower end of the cooling tube of the core assembly is in contact with the floating blocks. During the tube expansion process, the diameter of the cooling tube becomes thicker, the cooling tube is in interference contact with the fins, the length of the cooling tube becomes shorter, the floating blocks rebound and always contact the lower end of the cooling tube, maintaining the upward support force on the cooling tube, thereby counteracting the downward pressure of the stamping rod on the cooling tube during tube expansion, keeping the cooling tube stationary during the tube expansion process, thus ensuring that the upper end of the cooling tube extends sufficiently beyond the tube sheet after tube expansion and is uniformly aligned, ensuring the sealing and corrosion resistance of the tube sheet;

[0025] 2. The tube expansion method proposed in this application has a high degree of automation and low cost. It reduces the traditional tube head flipping and cutting processes, eliminates the risk of damaging the tube sheet, reduces the manufacturing cost of related processes, improves efficiency, and enhances the overall cost competitiveness of the product.

[0026] 3. By setting floating blocks on the base plate, the lower end of the cooling tube of the core assembly is made to contact the floating blocks. When the stamping rod starts to contact the cooling tube and causes the cooling tube to move downward, the floating blocks provide a lower limit for the cooling tube, so that each cooling tube is lowered to the predetermined position before the tube expansion begins. This ensures that the cooling tubes that were not originally aligned are now uniformly aligned after the tube expansion is completed.

[0027] 4. By setting a hinge, when the lifting positioning plate moves upward, it drives all the auxiliary positioning plates to move upward, and the auxiliary positioning plates maintain a predetermined distance from each other. When the lifting positioning plate moves downward, each auxiliary positioning plate reaches the lower limit from bottom to top in sequence. The auxiliary positioning plate that reaches the lower limit first does not affect the distance between the upper auxiliary positioning plates, ensuring that the corresponding position of the stamping tube is always corrected and limited by the auxiliary positioning plate during the descent process, thus adapting to core assemblies of different heights and having wider applicability. Attached Figure Description

[0028] Figure 1 This is a diagram showing the usage status of the pipe expander without flanges according to the present invention;

[0029] Figure 2 This is a perspective view of the pipe expander without flanges according to the present invention;

[0030] Figure 3 This is a perspective view of the support fixture of the present invention;

[0031] Figure 4 This is a perspective view of the heat exchanger core assembly of the present invention;

[0032] Figure 5 This is a top view of the base plate and floating blocks of the present invention;

[0033] Figure 6 For the present invention Figure 5 AA section diagram;

[0034] Figure 7 For the present invention Figure 5 Middle BB section view;

[0035] In the diagram: 1. Fixed base; 2. Sliding plate; 3. Base plate; 4. Support frame; 5. Stamping drive device; 6. Lifting positioning plate; 7. Stamping rod; 8. Expanding pipe end; 9. First support block; 10. Second support block; 11. Strip plate; 12. Spring; 13. Vertical guide groove; 14. Insert block; 15. Linear displacement drive device; 16. Auxiliary positioning plate; 17. Guide rod; 18. Hinge. Detailed Implementation

[0036] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] In the description of this invention, it should be noted that the terms "upper", "lower", "left", "right", "top", "bottom", "inner", "outer", "horizontal", "vertical", etc., 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 invention 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 limiting this invention.

[0038] like Figures 1 to 7 As shown, a heat exchanger tube expander without flanges includes a stamping mechanism and a support fixture. The support fixture includes a fixed base 1, a sliding plate 2 connected to the upper side of the fixed base 1 via a slide rail, a base plate 3 connected to the upper side of the sliding plate 2, a plurality of longitudinally parallel floating strips connected to the upper side of the base plate 3, and a support strip on the upper side of the base plate 3. The stamping mechanism includes a support frame 4, a stamping drive device 5 connected to the support frame 4, a lifting positioning plate 6 connected to the drive end of the stamping drive device 5, a plurality of stamping rods 7 connected to the lower side of the lifting positioning plate 6, and a tube expander end 8 connected to the lower end of the stamping rods 7.

[0039] One side of the heat exchanger core assembly tube sheet is placed on the support blocks of the support fixture, aligning several rows of cooling tubes of the core assembly with the floating blocks one by one, and aligning several stamping rods 7 with the corresponding cooling tubes one by one; the stamping drive device drives the stamping rods 7 to move downward until the tube expansion end 8 at the lower end of the stamping rod 7 contacts the upper end of the cooling tube; the stamping rod 7 continues to move downward, causing the tube expansion end 8 to squeeze the cooling tube, causing the entire cooling tube to move downward until the floating block in contact with the lower end of the cooling tube sinks to the limit position; the stamping rod continues to move downward, causing the tube expansion end 8 to squeeze into the cooling tube, expanding the cooling tube. During the tube expansion process, the diameter of the cooling tube becomes thicker, the cooling tube and the fins are in interference contact to ensure heat exchange efficiency, the length of the cooling tube becomes shorter, the floating blocks rebound, maintaining support for the cooling tube, until the tube expansion end 8 completely expands the cooling tube.

[0040] By setting floating blocks on the base plate 3, the lower end of the cooling tube of the core assembly contacts the floating blocks. During the tube expansion process, the diameter of the cooling tube becomes thicker, the cooling tube makes interference contact with the fins, the length of the cooling tube becomes shorter, the floating blocks rebound, and always contact the lower end of the cooling tube, maintaining the upward support force on the cooling tube. This counteracts the downward pressure of the stamping rod 7 on the cooling tube during tube expansion, keeping the cooling tube stationary during the tube expansion process. This ensures that after the tube expansion is completed, the upper end of the cooling tube extends sufficiently beyond the tube sheet and is uniformly aligned, ensuring the sealing and corrosion resistance of the tube sheet.

[0041] By setting floating blocks on the base plate 3, the lower end of the cooling tube of the core assembly contacts the floating blocks. When the stamping rod 7 starts to contact the cooling tube and causes the cooling tube to move downward, the floating blocks provide a lower limit for the cooling tube, so that each cooling tube descends to the predetermined position before the tube expansion begins. This ensures that the cooling tubes that were not originally aligned are now uniformly aligned after the tube expansion is completed.

[0042] In one embodiment, the support blocks include a first support block 9 and a second support block 10. The first support block 9 and the second support block 10 are symmetrically arranged at both ends of a plurality of floating blocks. The first support block 9 and the second support block 10 limit the horizontal movement of the plurality of floating blocks, ensuring that the plurality of floating blocks are evenly spaced and parallel. By setting the height of the first support block 9 and the second support block 10 to be higher than the floating blocks, they are used to support the core assembly tube sheet while also limiting the position of the floating blocks, integrating support and limiting functions and simplifying the structure.

[0043] In one embodiment, the floating block includes a strip plate 11 and several springs 12, with the springs 12 positioned between the strip plate 11 and the base plate 3. The springs 12 support the strip plate 11, allowing it to move vertically and providing floating support for the cooling pipe. Each strip plate 11 has several first mounting slots on its lower end face, and the base plate 3 has corresponding second mounting slots on its upper end face. The upper end of each spring 12 engages in one of the first mounting slots, and the lower end engages in one of the second mounting slots. By providing the first and second mounting slots, the position of the springs 12 is limited, allowing the strip plate 11 to move smoothly vertically and preventing horizontal deviation of the springs, which could cause one end of the strip plate 11 to tilt during vertical movement.

[0044] In one embodiment, the first support block 9 and the second support block 10 are each provided with a plurality of vertical guide grooves 13, with the vertical guide grooves on both sides arranged symmetrically. Each strip plate 11 has an insert block 14 connected to both ends, and the insert block 14 engages with the vertical guide groove 13, thereby allowing the strip plate 11 to move up and down along the vertical guide groove 13. Each vertical guide groove 13 has a height limiting plate at its upper end, and the insert block 14 is located between the height limiting plate and the bottom plate 3. By setting the height limiting plate, the spring 12 can always be in a compressed state, thereby adjusting the support force of the spring 12 on the cooling pipe within a suitable range.

[0045] In one implementation, the lower side of the lifting positioning plate 6 is provided with several threaded holes, and the upper end of the stamping rod 7 is connected to the lifting positioning plate 6 by threads, thereby adjusting the number and position of the stamping rod 7 to adapt to core assemblies of different models and structures, increasing applicability; several stamping rods are arranged longitudinally in one or two rows, with 8 to 15 stamping rods in each row. By pushing the sliding plate 2 to move relative to the fixed seat 1, all cooling pipes are processed sequentially, with only one or two rows of cooling pipes being expanded at a time, reducing the load on the stamping drive device and ensuring the success rate of pipe expansion.

[0046] The fixed base 1 is connected to a linear displacement drive device 15, and the drive end of the linear displacement drive device 15 is connected to the sliding plate 2. The linear displacement drive device 15 can be a hydraulic cylinder or a motor, which pushes the sliding plate 2 to move, so that each row of cooling pipes completes the expansion in sequence, and the displacement of the sliding plate 2 relative to the fixed base 1 is precisely controlled quantitatively.

[0047] In one implementation, a number of parallel auxiliary positioning plates 16 are sequentially arranged on the lower side of the lifting positioning plate 6, and a number of vertically arranged guide rods 17 are provided on the support frame 4. The guide rods 17 sequentially pass through the lifting positioning plate 6 and the number of auxiliary positioning plates 16; the stamping rod 7 sequentially passes through the number of auxiliary positioning plates 16. By setting a number of auxiliary positioning plates 16 on the lower side of the lifting positioning plate 6, the auxiliary positioning plates 16 straighten and guide the stamping rod 7 during the pressing process, keeping the stamping rod 7 in a vertical state and ensuring the accuracy of the tube expansion.

[0048] A hinge 18 connects each pair of adjacent auxiliary positioning plates 16, and a hinge 18 also connects the uppermost auxiliary positioning plate 16 to the lifting positioning plate 6. By setting the hinge 18, when the lifting positioning plate 6 moves upward, it drives all the auxiliary positioning plates 16 to move upward, maintaining a predetermined distance between each auxiliary positioning plate 16. When the lifting positioning plate 6 moves downward, each auxiliary positioning plate 16 reaches its lower limit sequentially from bottom to top. The auxiliary positioning plate 16 that reaches the lower limit first does not affect the distance between the upper auxiliary positioning plates 16, ensuring that the corresponding position of the stamping tube is always supported and limited by an auxiliary positioning plate 16 during the descent process. This adapts to core assemblies of different heights and has wider applicability.

[0049] The present invention also provides a method for expanding a tube without flanging, comprising the following steps:

[0050] S1. Place one side tube sheet of the heat exchanger core assembly on the support block of the support fixture, so that several rows of cooling tubes of the core assembly are aligned with the floating block one by one, and several stamping rods 7 are aligned with the corresponding cooling tubes one by one.

[0051] S2. The stamping drive device drives the stamping rod 7 to move downward until the expansion end 8 at the lower end of the stamping rod 7 contacts the upper end of the cooling pipe.

[0052] S3, the stamping rod 7 continues to move downward, causing the expansion tube end 8 to squeeze the cooling tube, causing the entire cooling tube to move downward until the floating strip that contacts the lower end of the cooling tube sinks to the limit position.

[0053] S4. The stamping rod continues to move downward, causing the expanding end 8 to be squeezed into the cooling pipe, expanding the cooling pipe. During the expansion process, the length of the cooling pipe becomes shorter, and the floating block rebounds, maintaining support for the cooling pipe, until the expanding end 8 completely expands the cooling pipe.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A tube expander for heat exchangers that does not require flanging, characterized in that, The device includes a stamping mechanism and a supporting fixture. The supporting fixture includes a fixed base (1), a sliding plate (2) connected to the upper side of the fixed base (1) via a slide rail, a base plate (3) connected to the upper side of the sliding plate (2), a plurality of longitudinally parallel floating strips connected to the upper side of the base plate (3), and a support strip on the upper side of the base plate (3). The stamping mechanism includes a support frame (4), a stamping drive device (5) connected to the support frame (4), a lifting positioning plate (6) connected to the drive end of the stamping drive device (5), a plurality of stamping rods (7) connected to the lower side of the lifting positioning plate (6), and an expansion tube end (8) connected to the lower end of the stamping rods (7). The floating block includes a strip plate (11) and a plurality of springs (12), with the plurality of springs (12) disposed between the strip plate (11) and the base plate (3); The support blocks include a first support block (9) and a second support block (10). The first support block (9) and the second support block (10) are symmetrically arranged at both ends of a plurality of floating blocks. The first support block (9) and the second support block (10) limit the plurality of floating blocks in the horizontal direction, so that the plurality of floating blocks are evenly spaced and parallel. The first support block (9) and the second support block (10) are respectively provided with a number of vertical guide grooves (13). The vertical guide grooves (13) on both sides are symmetrically arranged. Each strip plate (11) has a plug (14) connected to both ends. The plug (14) is engaged with the vertical guide groove (13).

2. The heat exchanger tube expander without flanges according to claim 1, characterized in that, Each of the strip plates (11) has a number of first mounting slots on its lower end face, and the base plate (3) has a number of second mounting slots on its upper end face corresponding to the number and position. The upper end of the spring (12) is inserted into the first mounting slot, and the lower end of the spring (12) is inserted into the second mounting slot.

3. The heat exchanger tube expander without flanges according to claim 1, characterized in that, Each of the vertical guide grooves (13) has a height limiting plate at its upper end, and the insert (14) is located between the height limiting plate and the bottom plate (3).

4. A tube expander for heat exchangers without flanges according to claim 1, characterized in that, The lower side of the lifting positioning plate (6) is provided with several threaded holes, and the upper end of the stamping rod (7) is connected to the lifting positioning plate (6) by thread; the several stamping rods (7) are arranged in one or two rows along the longitudinal direction, and the number of stamping rods in each row is set to 8 to 15.

5. A tube expander for heat exchangers without flanges according to claim 1, characterized in that, The fixed base (1) is connected to a linear displacement drive device (15), and the drive end of the linear displacement drive device (15) is connected to the sliding plate (2).

6. A tube expander for heat exchangers without flanges according to claim 1, characterized in that, The lower side of the lifting positioning plate (6) is provided with several parallel auxiliary positioning plates (16), and the support frame (4) is provided with several vertically arranged guide rods (17). The guide rods (17) pass through the lifting positioning plate (6) and several auxiliary positioning plates (16) in sequence; the stamping rod (7) passes through several auxiliary positioning plates (16) in sequence.

7. A tube expander for heat exchangers without flanges according to claim 6, characterized in that, A hinge (18) connects each pair of adjacent auxiliary positioning plates (16), and a hinge (18) also connects the uppermost auxiliary positioning plate (16) to the lifting positioning plate (6).

8. A method for expanding a tube without flanging, characterized in that, Includes the following steps: S1. Place one side tube sheet of the heat exchanger core assembly on the support bar of the support fixture, so that several rows of cooling tubes of the core assembly are aligned with the floating bar, and several stamping rods (7) are aligned with the corresponding cooling tubes. S2. The stamping drive device drives the stamping rod (7) to move downward until the expansion end (8) at the lower end of the stamping rod (7) contacts the upper end of the cooling pipe. S3. The stamping rod (7) continues to move downward, causing the expansion tube end (8) to squeeze the cooling tube, causing the entire cooling tube to move downward until the floating strip that contacts the lower end of the cooling tube sinks to the limit position. S4. The stamping rod continues to move downward, causing the expansion end (8) to be squeezed into the cooling pipe and expand the cooling pipe. During the expansion process, the length of the cooling pipe becomes shorter, and the floating strip rebounds to maintain support for the cooling pipe until the expansion end (8) completely expands the cooling pipe.

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