Method for manufacturing core of wound tube heat exchanger

Abstract

A method for manufacturing a core of a wound tube heat exchanger comprises the following steps: 1. inserting a central inner tube (4) into a central outer tube (1) along an axial direction and connecting the central inner tube (4) to the central outer tube (1) to obtain an intermediate support structure (100); and providing support discs at both ends of the support structure (100); 2. placing the intermediate support structure (100) flat and supporting it on a support seat for winding the tube via the support discs, and then spirally winding a heat exchange tube (200) on the outer peripheral wall of the central outer tube (1) to obtain an intermediate core structure; 3. extracting the central inner tube (4) from the central outer tube (1) to obtain a core having the central outer tube (1) and the heat exchange tube (200). Compared with the prior art, the present invention can avoid the central tube from being affected by excessive deflection and bending stress, and the central inner tube of the central outer tube can be reused after being extracted in step 3.

Description

Technical Field

[0001] The invention belongs to the technical field of heat exchangers, and in particular relates to a method for manufacturing a core of a wound tube heat exchanger. Background Art

[0002] At present, the core of the wound tube heat exchanger generally adopts the method of winding the heat exchange tube around the outer periphery of the center tube by rotating the center tube. For example, the tube winding machine disclosed in the invention patent with patent number ZL201410663041.9 "A Tube Winding Machine" (authorization announcement number CN104444563A) includes a supporting wheel for carrying the tube to be wound, a tube feeding device and a tube unwinding device. The tube feeding device includes, from bottom to top, a tube feeding base, a lifting mechanism, a fine adjustment mechanism, a support seat, a radial adjustment mechanism and a supporting wheel; the tube unwinding device includes a tube unwinding base, a chassis provided on the tube unwinding base, a bracket provided on the chassis, a turntable provided on the bracket, an axial clamping mechanism, a radial clamping mechanism, a telescopic sleeve, an anti-shrinkage mechanism and various sensors and control systems. This patent can track the inlet position of the tube in real time, adjust the tube feeding height, tube feeding angle and tube feeding speed, and ensure the quality of the tube winding.

[0003] The existing pipe winding operation has the following technical problems to be solved:

[0004] First, as Figure 1 As shown, the center tube 1' is arranged horizontally during the winding process. It is necessary to consider the deflection and bending stress of the center tube 1' during the winding process, and ensure that the deflection and bending stress of the center tube are controlled within a reasonable range. If the bending stress is too large, the center tube will be broken, thereby damaging the center tube; if the deflection of the center tube is too large, it will cause the following effects: 1. Too large a deflection will more easily cause fatigue fracture of the center tube; 2. Too large a deflection will cause a large deformation of the core, affecting subsequent assembly; 3. Too large a deflection will cause damage to the connection structure on the core, and it is easy to cause the entire core to delaminate, and the overall size of the entire core will become larger, affecting subsequent assembly; 4. Too large a deflection of the center tube will affect the balance of the entire winding system due to the excessive inclination of the circular support plates at both ends, thereby damaging the tube winding machine;

[0005] Second, if Figure 1 As shown, during tube winding, the center tube 1' is often supported on support blocks by circular tube sheets 2' at its ends. The circular tube sheets 2' are in contact with the support blocks and can rotate relative to them. As the tube winding operation progresses, the circular tube sheets may experience surface hardening, damage, and contamination, which can affect their subsequent use.

[0006] As the scale of applications expands, the diameter and length of heat exchangers are also increasing. Since they are wound horizontally, the diameter and thickness of the center tube must be increased accordingly to ensure that the turbulence and bending stress during the horizontal winding process are reduced. This increases the proportion of the center tube to the total mass of the heat exchanger, which invisibly increases the heat exchanger's appearance, weight, and manufacturing cost. However, in actual operation, heat exchangers are often installed vertically. For the center tube, the turbulence and bending stress during the winding process do not need to be considered. The only requirement is to ensure strength and rigidity during operation. Summary of the Invention

[0007] The first technical problem to be solved by the present invention is to provide a method for manufacturing the core of a wound tube heat exchanger based on the current status of the existing technology, so as to avoid the influence of winding on the central tube due to excessive deflection and bending stress, while reducing the weight of the equipment during operation.

[0008] The second technical problem to be solved by the present invention is to provide a method for manufacturing the core of a wound tube heat exchanger to avoid damage to the tube sheet during the winding process.

[0009] The technical solution adopted by the present invention to solve the first technical problem is: a method for manufacturing a core of a wound tube heat exchanger, characterized by the following steps:

[0010] 1. Insert the central inner cylinder axially into the central outer cylinder and connect them to the central outer cylinder to form an intermediate support structure; and provide support discs at both ends of the support structure;

[0011] 2. Lay the intermediate support structure flat and support it on the support base for winding the tubes through the support disc, and then spirally wind the heat exchange tubes around the outer peripheral wall of the central outer tube to obtain the intermediate core structure;

[0012] 3. Pull the central inner tube away from the central outer tube to obtain a core body having the central outer tube and the heat exchange tube.

[0013] Preferably, the central outer tube has a first end and a second end, and the first end of the central outer tube is connected to a first tube sheet, and the second end of the central outer tube is connected to a second tube sheet.

[0014] To further solve the second technical problem mentioned above, preferably, the central outer tube and the central inner tube are coaxially arranged, and the axial length of the central inner tube is greater than the length of the central outer tube, and the two ends of the central inner tube are respectively exposed outside the first end and the second end of the corresponding central outer tube; at the same time, the two ends of the central inner tube are respectively connected to detachable circular end plates, the center of the circular end plates is located on the axis of the central inner tube, and the diameters of the two circular end plates are the same and greater than the outer diameter of the central outer tube;

[0015] The two circular end plates are the supporting discs; or / and, the first tube plate and the second tube plate are the supporting discs.

[0016] In this way, when winding the tube, the intermediate support structure can be supported on the support seat through the two circular end plates to avoid damage to the tube sheet. Alternatively, it can be supported on the support seat directly through the first tube sheet and the second tube sheet.

[0017] In order to realize the detachable circular end plate, preferably, the circular end plate is connected to the end of the central inner tube by welding. In this way, when the circular end plate needs to be disassembled, the welding points at the welding place are removed and the desoldering process is carried out.

[0018] Preferably, the first tube sheet and the second tube sheet are respectively provided with a through hole for the end portion of the corresponding central inner tube to pass through;

[0019] The central inner cylinder in step 1 is connected to the central outer cylinder through the first tube sheet and the second tube sheet in the following manner:

[0020] The first tube sheet is connected to the outer peripheral wall of the central inner tube at a portion exposed outside the first tube sheet by welding, and the second tube sheet is connected to the outer peripheral wall of the central inner tube at a portion exposed outside the second tube sheet by welding.

[0021] In this way, before pulling the central inner tube out of the central outer tube in step three, the welding points between the central inner tube and the first tube sheet and the second tube sheet can be removed.

[0022] Preferably, in step 3, after the central inner tube is removed from the central outer tube, the through holes on the first and second tube sheets are sealed, thereby completing a core comprising the central outer tube, heat exchange tubes, and the first and second tube sheets. Of course, if the central outer tube is to be used as a flow path for the heat exchanger, the through holes may be left unsealed.

[0023] Furthermore, in step three, two sealing plates are used to seal the through holes on the first tube plate and the second tube plate respectively, and the side of each sealing plate is welded to the hole edge of the corresponding through hole.

[0024] Likewise, preferably, an annular flange extending axially outward is provided at the edge of each through hole of each tube sheet. In steps 1 and 2, the annular flange is sleeved on the outer circumference of the central inner cylinder and welded to the central inner cylinder.

[0025] In step three, two hemispherical and hollow heads are used to respectively block the through holes on the first tube sheet and the second tube sheet, and the annular end surface of each head is opposite to the corresponding annular flange and welded to each other.

[0026] The annular flange may be integrally formed with the tube sheet, or may be an independent component connected to the tube sheet by welding or other methods.

[0027] In each of the above schemes, in order to improve the stability of the intermediate support structure, preferably, along the first axial direction from the first end to the second end of the central outer tube, the central outer tube has a first straight tube section, a transition section, and a second straight tube section connected in sequence, the first straight tube section and the second straight tube section both extend along the first axial direction, and the inner diameter of the first straight tube section is larger than the inner diameter of the second straight tube section, the inner diameter of the transition section gradually decreases along the first axial direction, and the inner diameter of the large end of the transition section is consistent with the inner diameter of the first straight tube section, and the inner diameter of the small end of the transition section is consistent with the inner diameter of the second straight tube section;

[0028] The shape of the outer peripheral wall of the central inner tube is consistent with the shape of the inner peripheral wall of the central outer tube;

[0029] In step 1, the central inner cylinder is inserted into the central outer cylinder along the first axial direction.

[0030] In this way, the central inner tube is easily inserted into the central outer tube, and the transition section can be used as a limit to avoid axial displacement between the central inner tube and the central outer tube when winding the tube.

[0031] Preferably, in step 1 and step 2, the inner circumferential wall of the central outer cylinder is adjacent to or in contact with the outer circumferential wall of the central inner cylinder.

[0032] Compared with the prior art, the advantages of the present invention are: during the pipe winding operation, the central inner tube inserted into the central outer tube can increase the bending section modulus of the central tube, thereby reducing the bending stress of the central tube; and can increase the moment of inertia of the central tube section, reducing the deflection of the central tube. That is, the present invention can improve the strength and rigidity of the central tube, and avoid the central tube from being affected by excessive deflection and bending stress, and after the pipe winding is completed, the central inner tube is pulled out of the central outer tube, and the central outer tube wrapped with the heat exchange tube is used as the core body. The central inner tube can be reused in other central outer tubes that need pipe winding operations. Therefore, under the same strength, the present invention can reduce the diameter of the central outer tube, and then reduce the diameter of the heat exchanger, and further reduce the weight of the heat exchanger, and can also reduce the investment in the heat exchanger platform frame. The resulting reused central inner tube is also easy to manufacture and manage. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of the intermediate support structure of the prior art;

[0034] Figure 2 This is a schematic structural diagram of the intermediate support structure of the first embodiment of the present invention;

[0035] Figure 3 Schematic diagram of the structure of the core of Example 1 of the present invention (heat exchange tubes omitted);

[0036] Figure 4 for Figure 2 Diagram of the usage status during the winding process;

[0037] Figure 5 This is a schematic structural diagram of the core during transportation according to the first embodiment of the present invention;

[0038] Figure 6 This is a schematic structural diagram of the intermediate support structure of the second embodiment of the present invention;

[0039] Figure 7 This is a schematic structural diagram of the core body of the second embodiment of the present invention (heat exchange tubes omitted);

[0040] Figure 8 This is a schematic structural diagram of the intermediate support structure of the third embodiment of the present invention;

[0041] Figure 9 Schematic diagram of the structure of the core of the third embodiment of the present invention (heat exchange tubes omitted);

[0042] Figure 10 This is a schematic structural diagram of the intermediate support structure of the fourth embodiment of the present invention;

[0043] Figure 11 This is a schematic structural diagram of the core body of the fourth embodiment of the present invention (the heat exchange tube is omitted). DETAILED DESCRIPTION

[0044] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0045] Example 1:

[0046] like Figures 2 to 5 FIG. 1 is a preferred embodiment 1 of a method for manufacturing a core of a wound tube heat exchanger according to the present invention. The steps of the manufacturing method are as follows:

[0047] 1. Insert the central inner tube 4 axially into the central outer tube 1 and connect it to the central outer tube 1 to form the intermediate support structure 100;

[0048] 2. Lay the intermediate support structure 100 flat, and then spirally wind the heat exchange tube 200 around the outer circumferential wall of the central outer cylinder 1 to obtain the intermediate core structure;

[0049] 3. The central inner tube 4 is pulled out from the central outer tube 1 to obtain a core body having the central outer tube 1 and the heat exchange tubes 200.

[0050] In this embodiment, the intermediate support structure 100 includes, in addition to the central inner tube 4 and the central outer tube 1 , a first tube sheet 2 , a second tube sheet 3 and a circular end plate 5 .

[0051] The central outer cylinder 1 is hollow and has a first end and a second end in the axial direction. Along the first axial direction from the first end to the second end of the central outer cylinder 1, the central outer cylinder 1 comprises a first straight section 1a, a transition section 1b, and a second straight section 1c, which are sequentially connected. The first straight section 1a and the second straight section 1c both extend along the first axial direction. The end of the first straight section 1a is the first end of the central outer cylinder 1, and the end of the second straight section 1c is the second end of the central outer cylinder 1. The outer diameter of the first straight section 1a is greater than the outer diameter of the second straight section 1c. The outer diameter of the transition section 1b gradually decreases along the first axial direction. The outer diameter of the large end of the transition section 1b is consistent with the outer diameter of the first straight section 1a, and the outer diameter of the small end of the transition section 1b is consistent with the outer diameter of the second straight section 1c. At the same time, the inner diameter of the first straight cylindrical section 1a is larger than the inner diameter of the second straight cylindrical section 1c, the inner diameter of the transition section 1b gradually decreases along the first axial direction, the inner diameter of the large head end of the transition section 1b is consistent with the inner diameter of the first straight cylindrical section 1a, and the inner diameter of the small head end of the transition section 1b is consistent with the inner diameter of the second straight cylindrical section 1c.

[0052] The first tube sheet 2 is mounted at the first end of the central outer tube 1, and the second tube sheet 3 is mounted at the second end of the central outer tube 1. Both the first tube sheet 2 and the second tube sheet 3 are circular, with their centers located on the central axis of the central outer tube 1. A circular through-hole 20 extending through the thickness of each tube sheet is provided in the center of each tube sheet. The diameter of the through-hole 20 in the first tube sheet 2 is consistent with the inner diameter of the first straight section 1a, while the diameter of the through-hole 20 in the second tube sheet 3 is consistent with the inner diameter of the second straight section 1c.

[0053] The central inner tube 4 is axially inserted within the central outer tube 1, coaxially arranged with the central outer tube 1. The outer circumferential wall of the central inner tube 4 is shaped identically to the inner circumferential wall of the central outer tube 1, and the outer circumferential wall of the central inner tube 4 is adjacent to or abuts the inner circumferential wall of the central outer tube 1. Furthermore, the axial length of the central inner tube 4 is greater than that of the central outer tube 1. Its ends extend through the through-holes 20 in the first and second tube sheets 2 and 3, respectively, and are exposed at the first and second ends of the central outer tube 1. Furthermore, the outer circumferential wall of the central inner tube 4, exposed at the first end, is welded to the first tube sheet 2, with the weld point 40 located at the edge of the through-hole 20 in the first tube sheet 2. The outer circumferential wall of the central inner tube 4, exposed at the second end, is welded to the second tube sheet 3, with the weld point 40 located at the edge of the through-hole 20 in the second tube sheet 3. In order to facilitate the insertion of the central inner cylinder 4 into the central outer cylinder 1 , lubricant may be applied to the outer circumferential wall of the central inner cylinder 4 and / or the inner circumferential wall of the central outer cylinder 1 before insertion.

[0054] There are two circular end plates 5, which are welded to both ends of the central inner cylinder 4. The diameters of the two circular end plates 5 are the same and larger than the outer diameter of the central outer cylinder 1. The center of each circular end plate 5 is located on the central axis of the central outer cylinder 1.

[0055] In step 2 of this embodiment, the intermediate support structure 100 is placed horizontally, that is, the central axis of the central outer cylinder 1 extends in the horizontal direction, and the two circular end plates 5 or two tube sheets are supported on the support seats for pipe winding, so that the intermediate support structure 100 can be rotated around the central axis to perform the pipe winding operation. Figure 4 .

[0056] like Figure 3 As shown, in step three, after the winding operation is completed, the welding points 40 between the central inner tube 4 and the corresponding tube sheet are removed (i.e., the welding process is performed), and the welding points between at least one of the circular end plates 5 and the central inner tube 4 are removed, and then the central inner tube 4 is pulled outward and separated from the central outer tube 1; then two sealing plates 6 are taken, respectively set at the through holes 20 of the first and second tube sheets, to seal the through holes 20. The sealing plates 6 are circular, and their edges are welded to the hole edges of the corresponding through holes 20, and the core of the heat exchanger can be obtained.

[0057] like Figure 5 As shown, in order to prevent the core of the heat exchanger from being deformed during transportation or assembly, a thick steel plate can be wrapped around the middle part of the core along the circumference to protect the core.

[0058] Example 2:

[0059] like Figure 6 、 7 FIG. 2 shows a preferred embodiment 2 of the method for manufacturing the core of a wound tube heat exchanger according to the present invention. This embodiment is substantially the same as the first embodiment, except that an annular flange 21 extending axially outward is integrally formed at the edges of the through-holes 20 of the first tube sheet 2 and the through-holes 20 of the second tube sheet 3. The annular flange 21 is sleeved around the outer circumference of the central inner tube 4 and welded thereto. In other words, the welding point 40 in this embodiment is located on the annular flange 21.

[0060] At the same time, in this embodiment, Figure 7 As shown, a hemispherical head 7 with a hollow interior is used instead of the sealing plate 6 to seal the through hole 20, and the annular end surface of the head 7 is opposite to the annular flange 21 and welded to each other.

[0061] Example 3:

[0062] like Figure 8 、 9The figure shows a preferred embodiment 3 of the method for manufacturing the core of a wound tube heat exchanger of the present invention. This embodiment is basically the same as the second embodiment, except that it further includes a cylindrical short section 8 extending outward from each annular flange 21 along the axial direction of the central outer tube 1. The two short sections 8 are respectively connected to the corresponding annular flanges 21 (which can be welded or integrally formed, etc.). In steps 1 and 2, the short sections 8 are sleeved on the outer circumference of the central inner tube 4, and the above-mentioned welding point 40 is located on the outer end of the short section 8. In step 3, after the winding is completed and the central inner tube 4 is withdrawn, the annular end face of the head 7 is opposite to the outer end face of the short section 8 and welded.

[0063] Example 4:

[0064] like Figure 10 、 11 As shown, it is a preferred embodiment 4 of the method for manufacturing the core of the wound tube heat exchanger of the present invention. This embodiment is basically the same as the third embodiment, except that the components in this embodiment are connected by surfacing.

Claims

1. A method for manufacturing a core of a wound tube heat exchanger, characterized in that Here are the steps:

1. Inserting the central inner cylinder (4) into the central outer cylinder (1) along the axial direction and connecting the central inner cylinder (4) with the central outer cylinder (1) to obtain an intermediate support structure (100); and providing support discs at both ends of the support structure (100); 2. Laying the intermediate support structure (100) flat and supporting it on a support base for winding the tube via the support disc, and then spirally winding the heat exchange tube (200) on the outer peripheral wall of the central outer tube (1) to obtain the intermediate core structure; 3. Pulling the central inner tube (4) away from the central outer tube (1) to obtain a core having the central outer tube (1) and the heat exchange tube (200); Along the first axial direction from the first end to the second end of the central outer cylinder (1), the central outer cylinder (1) has a first straight cylinder section (1a), a transition section (1b) and a second straight cylinder section (1c) connected in sequence, the first straight cylinder section (1a) and the second straight cylinder section (1c) both extend along the first axial direction, and the inner diameter of the first straight cylinder section (1a) is larger than the inner diameter of the second straight cylinder section (1c), the inner diameter of the transition section (1b) gradually decreases along the first axial direction, and the inner diameter of the large end of the transition section (1b) is consistent with the inner diameter of the first straight cylinder section (1a), and the inner diameter of the small end of the transition section (1b) is consistent with the inner diameter of the second straight cylinder section (1c); The shape of the outer peripheral wall of the central inner cylinder (4) is consistent with the shape of the inner peripheral wall of the central outer cylinder (1); In step 1, the central inner cylinder (4) is inserted into the central outer cylinder (1) along the first axial direction.

2. The production method according to claim 1, characterized in that: The central outer tube (1) has a first end and a second end, and the first end of the central outer tube (1) is connected to a first tube sheet (2), and the second end of the central outer tube (1) is connected to a second tube sheet (3).

3. The production method according to claim 2, characterized in that: The central outer cylinder (1) and the central inner cylinder (4) are coaxially arranged, and the length of the central inner cylinder (4) in its axial direction is greater than the length of the central outer cylinder (1), and the two ends of the central inner cylinder (4) are respectively exposed outside the first end and the second end of the corresponding central outer cylinder (1); at the same time, the two ends of the central inner cylinder (4) are respectively connected to detachable circular end plates (5), the center of the circular end plates (5) is located on the axis of the central inner cylinder (4), and the diameters of the two circular end plates (5) are the same and greater than the outer diameter of the central outer cylinder (1); The two circular end plates (5) are the supporting discs; or / and, the first tube plate (2) and the second tube plate (3) are the supporting discs.

4. The production method according to claim 3, characterized in that: The circular end plate (5) is connected to the end of the central inner cylinder (4) by welding.

5. The production method according to claim 2, characterized in that: The first tube sheet (2) and the second tube sheet (3) are respectively provided with through holes (20) for the ends of the corresponding central inner cylinders (4) to pass through; The central inner cylinder (4) of step 1 is connected to the central outer cylinder (1) through the first tube sheet (2) and the second tube sheet (3) by: The first tube sheet (2) and the outer peripheral wall of the central inner tube (4) exposed outside the first tube sheet (2) are connected by welding, and the second tube sheet (3) and the outer peripheral wall of the central inner tube (4) exposed outside the second tube sheet (3) are connected by welding.

6. The production method according to claim 5, characterized in that: In the step three, after the central inner tube (4) is pulled out of the central outer tube (1), the through holes (20) on the first tube sheet (2) and the second tube sheet (3) are sealed, thereby obtaining a core body having the above-mentioned central outer tube (1), heat exchange tubes (200) and the first tube sheet (2) and the second tube sheet (3).

7. The production method according to claim 6, characterized in that: In the step three, two sealing plates (6) are used to seal the through holes (20) on the first tube plate (2) and the second tube plate (3), respectively, and the side edges of each sealing plate (6) are welded to the hole edges of the corresponding through holes (20).

8. The production method according to claim 6, characterized in that: An annular flange (21) extending outward in the axial direction is provided at the edge of each through hole (20) of each tube plate. In steps 1 and 2, the annular flange (21) is sleeved on the outer periphery of the central inner cylinder (4) and welded to the central inner cylinder (4); In step three, two hemispherical and hollow internal sealing heads (7) are used to respectively seal the through holes (20) on the first tube sheet (2) and the second tube sheet (3), and the annular end faces of each sealing head (7) are opposite to the corresponding annular flange (21) and welded to each other.

9. The method according to any one of claims 1 to 8, characterized in that: In step 1 and step 2, the inner peripheral wall of the central outer cylinder (1) is adjacent to or in contact with the outer peripheral wall of the central inner cylinder (4).

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