Heat exchange plate group connecting structure, heat exchanger and heat exchange plate reaming device
By optimizing the connection structure between the heat exchange plate and the pipeline and using a waist hole reaming device, the problem of difficulty in replacing the heat exchange plate alone is solved, convenient replacement and stable flow of the heat transfer medium are achieved, and maintenance costs and resource waste are reduced.
Patent Information
- Application Number
- CN202422181494.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-05
- Publication Date
- 2025-08-15
- Estimated Expiration
- 2034-09-05
AI Technical Summary
In the existing heat exchange plate connection structure, it is difficult to replace the heat exchange plate pieces separately, resulting in waste of resources and increased costs. Especially when there is blockage or leakage, the entire heat exchange plate group needs to be replaced.
The plate thickness of the heat exchange plate is designed to be smaller than the width of the pipe, forming a gap and approaching the middle of the connecting piece. It is connected with U-shaped steel, and the notch is slightly larger than the thickness of the plate, making it easy to replace; the waist hole and hole reaming device are used to improve the connection strength and stability.
It realizes convenient replacement of heat exchange plates, reduces maintenance difficulty and cost, and improves the maintenance efficiency of heat exchangers and the flow stability of heat transfer media.
Smart Images
Figure CN223228855U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of heat exchanger manufacturing, and in particular to a heat exchange plate group connection structure, a heat exchanger, and a heat exchange plate hole expanding device. Background Art
[0002] Melt crystallization is a method for separating and purifying substances based on the differences in freezing points between the substances to be separated. It has the characteristics of low operating temperature, low energy consumption, high product purity, and environmental friendliness. In the separation and purification process of organic mixtures such as isomers, azeotropes, or heat-sensitive substances in chemical and pharmaceutical production, it is generally difficult to obtain high-purity or ultra-high-purity products if conventional separation methods (such as distillation) are used. In addition, the temperature requirement of the distillation operation is high, and the latent heat of vaporization of the substance is much higher than the latent heat of crystallization, so distillation has high energy consumption. In comparison, the melt crystallization method has the advantages of high product purity and low production energy consumption.
[0003] The melt crystallization process places high demands on the performance of the heat transfer system. The heat exchange equipment used to circulate the heat transfer medium within the melt crystallizer generally uses honeycomb expanded heat exchange plates with high heat transfer coefficients. To improve space utilization within the crystallizer, multiple heat exchange plates are usually grouped into a heat exchange plate group, and the multiple heat exchange plates can be connected and fixed with steel sections.
[0004] Figure 1 、 Figure 2 and Figure 3 The figure shows a heat exchange plate connection structure known to the inventor, which may include a plate 1, a pipe 2 and a U-shaped steel 3. The plate 1 is a hollow plate with a heat exchange medium inside. The plate 1 can be welded to the pipe 2. A rectangular cutout can be formed at the weld between the plate 1 and the pipe 2. Part of the pipe 2 is provided on the plate 1, and the lower edge of the pipe 2 is lower than the upper edge of the plate 1. The U-shaped steel 3 can be formed with a notch slightly larger than the thickness of the plate 1 (edge thickness), and the edge of the plate 1 can be stuck into the notch of the U-shaped steel 3. The U-shaped steel 3 can be provided with multiple notches along its length, and then multiple plates 1 can be connected through the U-shaped steel to form a heat exchange plate group.
[0005] The welding point between the plate 1 and the pipe 2 is a common tube-sheet welding structure, which has a large welding volume, poor welding strength, concentrated welding materials, and is prone to deformation. Figure 3 As shown, the diameter of the pipe 2 is greater than the thickness of the plate 1, and the diameter of the pipe 2 is greater than the width of the notch of the U-shaped steel.
[0006] It is understandable that Figure 1As shown, after the plate 1 is clamped with the U-shaped steel 3, the lower edge of the U-shaped steel 3 will be lower than the upper edge of the plate 1. When a plate 1 in the heat exchange plate group fails and needs to be replaced, the pipe 2 is usually cut along the upper edge of the plate 1 to separate the plate 1 from the portion of the pipe 2 (the portion of the pipe 2 that is higher than the plate 1). Figure 1 and Figure 3 When pulling out a plate 1 (left or right), the connecting pipe 2 connected to the plate 1 is blocked by the U-shaped steel 3, making it difficult to smoothly remove the plate 1 to be replaced from the heat exchange plate assembly. Because the diameter of the connecting pipe 2 is greater than the thickness of the plate 1, the heat transfer medium will experience significant pressure and flow rate fluctuations when flowing from the connecting pipe 2 to the plate 1, which is not conducive to the stable flow of the heat transfer medium.
[0007] It is difficult to replace the plates 1 in the above heat exchange plate connection structure individually. When a single plate has problems such as blockage or leakage, the entire heat exchange plate group often needs to be replaced, resulting in resource waste and increased costs. Utility Model Content
[0008] This application is made in view of the above-mentioned state of the prior art. The purpose of this application is to provide a heat exchange plate group connection structure that is easy to replace heat exchange plates.
[0009] The present application also provides a heat exchanger including the above-mentioned heat exchange plate group connection structure, and also provides a heat exchange plate hole expanding device.
[0010] The present application provides a heat exchange plate group connection structure, which includes a plurality of heat exchange plates, a plurality of pipes and at least one connecting piece.
[0011] The connecting piece connects the plurality of heat exchange plates.
[0012] The plurality of heat exchange plates are respectively connected to the plurality of pipes by welding, and the thickness of the heat exchange plates is smaller than the width of the pipes in the plate thickness direction.
[0013] A notch is formed at the location where the heat exchange plate is connected to the pipe.
[0014] The bottom of the notch is close to the middle of the heat exchange plate relative to the connecting piece.
[0015] A gap is formed between the bottom of the notch and the connecting piece in an extending direction of the pipe connected to the notch.
[0016] In at least one possible embodiment, the notch is a "V-shaped" notch.
[0017] The “V-shaped” notch includes two inclined edges, and the two edges form an angle smaller than 180 degrees.
[0018] In at least one possible embodiment, at least two connecting members are provided on a side of the heat exchange plate connected to the pipeline, and the pipeline is provided between the two connecting members.
[0019] In at least one possible embodiment, the cross-section of one end of the pipe connected to the heat exchange plate is oblong, and the interface connecting the pipe to the heat exchange plate is oblong.
[0020] In at least one possible embodiment, the connecting piece is made of "U-shaped" steel; and / or the heat exchange plate is a honeycomb heat exchange plate.
[0021] In at least one possible embodiment, the pipe is connected to a region of the heat exchange plate that accommodates the heat exchange medium.
[0022] In at least one possible embodiment, the connecting member is formed with a plurality of notches along its length, and the notches are engaged with the heat exchange plates.
[0023] The groove width of the notch is greater than the thickness of the edge region of the heat exchange plate; and / or the groove width of the notch is smaller than the width of the pipe in the plate thickness direction.
[0024] In at least one possible embodiment, at least one connecting member is provided on both the side of the heat exchange plate connected to the pipeline and the opposite side thereof.
[0025] The present application also provides a heat exchanger, which includes the aforementioned heat exchange plate group connection structure,
[0026] The plurality of heat exchange plates are distributed in parallel along the length direction of the connecting piece.
[0027] The plurality of pipes are connected to a main pipe so as to pass heat exchange medium into the plurality of heat exchange plates.
[0028] The present application also provides a heat exchange plate reaming device for machining waist-shaped holes on heat exchange plates. The heat exchange plate reaming device comprises an operating portion, a frame, and a drill bit. The frame is used to clamp to both sides of the heat exchange plate.
[0029] An internal threaded hole is formed on the upper portion of the frame.
[0030] The operating portion forms an external thread portion,
[0031] One end of the drill bit forms a waist-shaped portion,
[0032] The drill bit and the external threaded portion can be at least partially disposed in the internal threaded hole and move axially along the internal threaded hole, and the waist-shaped portion can at least partially extend into the heat exchange plate to expand a waist-shaped hole on the heat exchange plate.
[0033] The heat exchange plate group connection structure and heat exchanger provided in the present application can improve the structural strength of the tube-sheet connection, facilitate the replacement of heat exchange plates with problems such as blockage and leakage, reduce the difficulty of replacing and repairing the heat exchange plates, improve the maintenance efficiency of the heat exchanger, and reduce equipment maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Figure 1 This is a front view schematic diagram of a heat exchange plate connection structure known to the inventor.
[0035] Figure 2 This is a side structural schematic diagram of a heat exchange plate connection structure known to the inventor.
[0036] Figure 3 The figure is a schematic top view of a heat exchange plate connection structure known to the inventor.
[0037] Figure 4 It is a front view structural schematic diagram of a heat exchange plate connection structure according to one embodiment of the present application.
[0038] Figure 5 It is a side structural schematic diagram of a heat exchange plate connection structure according to one embodiment of the present application.
[0039] Figure 6 Schematic diagram of a top view of a heat exchange plate connection structure according to one embodiment of the present application.
[0040] Figure 7 It is a schematic structural diagram of a heat exchanger according to one embodiment of the present application.
[0041] Figure 8 for Figure 4 A partial enlarged schematic diagram of the heat exchange plate connection structure is shown.
[0042] Figure 9 Schematic diagram of the structure of the pipeline bottom according to one embodiment of the present application.
[0043] Figure 10 This is a schematic structural diagram of a waist-shaped hole of a pipe according to one embodiment of the present application.
[0044] Figure 11 This is a structural schematic diagram of the connection between the reaming device and the heat exchange plate according to one embodiment of the present application.
[0045] Figure 12 This is a structural schematic diagram of the connection between the reaming device and the heat exchange plate according to one embodiment of the present application.
[0046] Figure 13 Schematic diagram of the structure of a drill bit according to one embodiment of the present application.
[0047] Figure 14 It is a schematic cross-sectional view of a drill bit according to one embodiment of the present application.
[0048] Description of Reference Numerals
[0049] 1 plate
[0050] 2 Takeover
[0051] 3 U-shaped steel
[0052] 10 heat exchange plates
[0053] 11 Gap
[0054] 20 Pipeline
[0055] 21 Pipe bottom
[0056] 30 Connectors
[0057] 100 heat exchanger
[0058] 110 Main Pipeline
[0059] 200 Hole expansion device
[0060] 210 Operation Department
[0061] 211 External thread
[0062] 220 framework
[0063] 221 internal threaded hole
[0064] 230 drill bit
[0065] 231 Waist DETAILED DESCRIPTION
[0066] The following describes exemplary embodiments of the present application with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present application, and are not intended to exhaust all possible embodiments of the present application, nor to limit the scope of the present application.
[0067] It should be understood that although the above description Figure 1 、 Figure 2 and Figure 3 Although the heat exchange plate group connection structure shown in FIG has some disadvantages, the heat exchange plate group connection structure still has certain advantages compared with some existing technologies. Figure 1 、 Figure 2 and Figure 3 And some features in the above description may still constitute part of the disclosure or implementation of this application.
[0068] The embodiment of the present application provides a heat exchange plate group connection structure, such as Figure 4 、 Figure 5 and Figure 6 As shown, the heat exchange plate group connection structure may include multiple heat exchange plates 10, multiple pipes 20 and at least one connector 30. The multiple heat exchange plates 10 may be welded to the multiple pipes 20 respectively, and the connector 30 may be used to connect the multiple heat exchange plates 10.
[0069] Preferably, the width of the pipe 20 in the thickness direction of the heat exchange plate 10 may be greater than the thickness of the heat exchange plate 10 .
[0070] Preferably, the connecting member 30 in this embodiment can be a U-shaped steel. It is understood that the connecting member 30 can also be a channel steel, an angle steel, a steel pipe, etc.
[0071] Preferably, the heat exchange plate 10 in this embodiment may be a honeycomb heat exchange plate.
[0072] The U-shaped steel connector 30 can be connected along its length ( Figure 5 Notches are evenly formed in the left and right directions of the heat exchange plate 10, and the edges of the heat exchange plates 10 can be snapped into the notches to connect multiple heat exchange plates 10 through the connector 30. In actual applications, the width of the notch of the connector 30 is slightly larger than the thickness of the edge area of the heat exchange plate 10, and the width of the notch is usually smaller than the width of the pipe 20 in the plate thickness direction of the heat exchange plate. In the heat exchange plate connection structure in the background technology, the connector will hinder the passage of the heat exchange plate of the connected part of the pipe. The embodiment of the present application improves this defect so that the heat exchange plate can be smoothly pulled out. It can be understood that the connector 30 can be set according to actual needs. For example, in Figure 4 and Figure 6 In the embodiment, two connecting pieces 30 are provided on the upper edge of the heat exchange plate 10; Figure 7 In the embodiment, two connecting pieces 30 are provided on the upper edge and the lower edge of the heat exchange plate 10 (ie, the side of the heat exchange plate connected to the pipe, ie, the opposite side thereof).
[0073] Preferably, both the pipe 20 and the connector 30 can be connected to the upper edge of the heat exchange plate 10 .
[0074] More preferably, two connectors 30 may be provided on the upper edge of the heat exchange plate 10 , and the pipe 20 may be provided between the two connectors 30 .
[0075] like Figure 4 and Figure 8As shown, the edge of the heat exchange plate 10 connecting the pipe 20 may form a notch 11. Preferably, the notch 11 may be a "V-shaped" notch. It should be understood that "V-shaped" here means that the notch includes two inclined edges, and the two edges may form an angle less than 180 degrees. The bottom of the "V-shaped" notch may form an angle, or may be flat, curved, or the like.
[0076] like Figure 8 As shown, the pipe 20 is connected to the notch 11 of the heat exchange plate 10. The connection between the pipe 20 and the heat exchange plate 10 can have a certain depth. Specifically, the lower edge (inner bottom) of the connector 30 is located at L1, the bottom of the notch 11 at the connection between the pipe 20 and the heat exchange plate 10 is located at L2, and the area between L1 and L2 can be S. Preferably, L1 can be higher than L2 (such as Figure 4 、 Figure 7 and Figure 8 The pipe 20 shown in the figure is arranged on the upper part of the heat exchange plate 10; it can be understood that the pipe 20 can also be arranged on the lower part of the heat exchange plate 10, in which case L1 is lower than L2, that is, the bottom of the notch 11 at the connection between the pipe 20 and the heat exchange plate 10 can be closer to the middle of the heat exchange plate 10 relative to the connector 30 (the edge of the connector near the middle of the heat exchange plate 10). The bottom of the notch 11 can be separated from the connector 30 (the edge of the connector 30 near the middle of the heat exchange plate 10) by a certain distance (i.e., "S") in the extension direction of the pipe 20 (when the pipe 20 is curved as a whole, the extension direction of the part of the pipe directly connected to the notch 11 is used as a reference). In the actual welding operation of the pipe 20 and the heat exchange plate 10, the solder is mainly concentrated in the overlapping area of the heat exchange plate 10 and the pipe 20, that is, the solder is mainly concentrated in the area below L1. It can be understood that the pipe 20 can also be connected to the bottom of the heat exchange plate 10. In this case, the bottom of the notch 11 at the connection between the pipe 20 and the heat exchange plate 10 can be closer to the middle of the heat exchange plate 10 relative to the connecting piece 30 (the edge of the connecting piece close to the middle of the heat exchange plate 10).
[0077] It is understood that the thickness of the edge region of the heat exchange plate 10 may be thinner than the thickness of the heat exchange medium accommodating region in the middle of the heat exchange plate 10. The pipe 20 may be directly connected to the heat exchange medium accommodating region of the heat exchange plate 10, that is, the bottom of the notch 11 may be formed in a non-edge region of the heat exchange plate 10, that is, in the heat exchange medium accommodating region.
[0078] It can be understood that in the heat exchange plate group connection structure provided in the embodiment of the present application, when the heat exchange plate has a fault such as leakage or blockage, the pipe 20 can be cut in the S area, that is, the cutting point of the pipe 20 can be lower than L1 and higher than L2. At this time, the heat exchange plate 10 to be replaced is pulled in the vertical direction along the length direction of the connector 30, and the remaining part of the pipe 20 on the heat exchange plate 10 will not be blocked by the connector 30 (the upper end of the remaining part of the pipe 20 is lower than the lower edge of the connector 30). After the heat exchange plate 10 to be replaced is pulled out, the new heat exchange plate can be set to the replacement position along the original extraction path. The new heat exchange plate to be replaced can have a partial pipe structure for welding and connecting with the cut original pipe. It can be understood that the above-mentioned heat exchange plate group connection structure, that is, the heat exchange plate replacement method, can realize the convenient and quick replacement of the faulty heat exchange plates in the heat exchange plate group, reduce the difficulty of replacing the heat exchange plates, and improve the replacement efficiency.
[0079] Further, such as Figure 9 and Figure 10 As shown, the portion of the pipe 20 that connects to the heat exchange plate 10 is the pipe bottom 21. At least a portion of the pipe bottom 21 can have an oblong cross-section, and the interface between the pipe bottom 21 and the heat exchange plate 10 can also be oblong (i.e., a waist-shaped interface). Correspondingly, the heat exchange plate 10 can also have corresponding waist-shaped holes, allowing the pipe bottom 21 to at least partially insert into the heat exchange plate 10.
[0080] It can be understood that the waist-shaped hole has a higher connection strength than the round hole, which can make the connection between the pipe 20 and the heat exchange plate 10 tighter. In addition, the structure of the pipe bottom 21 has a smaller width in the plate thickness direction, so the connection transition with the heat exchange plate 10 will be smoother, which can facilitate welding operations without the need for filler welding. The waist-shaped hole-type pipe hole connection structure can make the pipe less likely to rotate, which facilitates the connection between the pipe 20 and the heat exchange plate 10. The pipe bottom 21 with a waist-shaped cross-section can reduce the changes in pressure and flow rate during the process of the heat transfer medium flowing from the pipe 20 to the heat exchange plate 10, making the flow of the heat transfer medium here smoother and reducing flow resistance.
[0081] The embodiment of the present application further provides a heat exchanger, which may include the above-mentioned heat exchanger connection structure. Figure 7 As shown, the heat exchanger may include multiple heat exchange plates 10, which may be arranged in parallel along the length of the connector 30, and in particular, may be arranged evenly (with the same spacing). Multiple pipes 20 may be connected to the same main pipe 110 to pass heat exchange medium into the multiple heat exchange plates 10.
[0082] The embodiment of the present application also provides a heat exchange plate reaming device (hereinafter sometimes referred to as "reaming device"), which can be used for reaming the aforementioned heat exchange plate 10. As mentioned above, both the heat exchange plate 10 and the pipe 20 can form waist-shaped holes to improve the connection strength. The heat exchange plate reaming device provided in this embodiment is particularly suitable for processing and forming waist-shaped holes on the heat exchange plate 10. The heat exchange plate 10 with a waist-shaped hole is matched with the pipe bottom 21 with a waist-shaped interface (waist-shaped cross-section), which can make the flow of the heat exchange medium at the connection between the two smoother and more stable, and reduce the flow resistance of the heat exchange medium. In addition, the welding connection between the pipe 20 and the heat exchange plate 10 is easier to operate, avoiding filling welding, and making the welding connection more secure.
[0083] like Figure 11 and Figure 12 As shown, the reaming device 200 may include an operating portion 210, a frame 220, and a drill bit 230. Figure 12 As shown, the frame 220 can be clamped on both sides of the heat exchange plate 10 to improve the stability during the hole expansion operation. Figure 11 As shown, the frame 220 can be arranged on both sides of the notch 11 of the heat exchange plate 10. The upper portion of the frame 220 can have an internal threaded hole 221, and the lower portion of the operating portion 210 can be formed with an external threaded portion 211, and the external threaded portion 211 can move along the axial direction of the internal threaded hole 221 (spirally move along the thread). Figure 13 and Figure 14 As shown, one end of the drill bit 230 may have a waist-shaped portion 231 (ie, the tip of the drill bit 230 ) for expanding the hole on the heat exchange plate 10 .
[0084] like Figure 12 As shown, when expanding the heat exchange plate 10, the waist-shaped portion 231 of the drill bit 230 can be aligned with or partially enter the notch 11 of the heat exchange plate 10. The other end of the drill bit 230 (the end without the waist-shaped hole) can be set in the internal threaded hole 221. The external threaded portion 210 of the operating part 210 is inserted (screwed in) from the other side of the internal threaded hole 221 (the side of the internal threaded hole without the drill bit), and the operating part 210 is rotated along the thread to squeeze the drill bit 230, so that the waist-shaped portion 231 of the drill bit 230 can be inserted into the heat exchange plate 10, thereby completing the expansion of the heat exchange plate 10.
[0085] It can be understood that the heat exchange plate group connection structure, heat exchanger and heat exchange plate expansion device provided in the embodiments of the present application are particularly suitable for melt crystallization processes, but their scope of application is not limited thereto.
[0086] The following briefly describes some of the beneficial effects of the above-mentioned embodiments of the present application.
[0087] The heat exchange plate assembly connection structure and heat exchanger provided by the embodiments of the present application can facilitate the replacement of heat exchange plates that have problems such as blockage and leakage, reduce the difficulty of replacing and repairing heat exchange plates, improve the repair efficiency of the heat exchanger, and reduce equipment maintenance costs. The hole expansion device provided by the embodiments of the present application can quickly and easily form waist-shaped holes on the heat exchange plates, thereby improving the connection strength between the heat exchange plates and the pipeline.
[0088] It is understood that in this application, when the number of parts or components is not specifically limited, the number may be one or more, and in this case, two or more. If the number of parts or components is shown in the drawings and / or described in the specification as a specific number such as two, three, or four, the specific number is generally illustrative and not restrictive, and can be understood as two or more. However, this does not mean that this application excludes the case of one.
[0089] It should be understood that the above embodiments are merely exemplary and are not intended to limit the present application. Those skilled in the art may make various modifications and changes to the above embodiments based on the teachings of the present application without departing from the scope of the present application.
Claims
1. A heat exchange plate group connection structure, characterized in that: It includes a plurality of heat exchange plates, a plurality of pipes and at least one connecting piece. The connecting piece connects the plurality of heat exchange plates. The plurality of heat exchange plates are respectively connected to the plurality of pipes by welding, and the thickness of the heat exchange plates is smaller than the width of the pipes in the plate thickness direction. A notch is formed at the location where the heat exchange plate is connected to the pipe. The bottom of the notch is close to the middle of the heat exchange plate relative to the connecting piece. A gap is formed between the bottom of the notch and the connecting piece in an extending direction of the pipe connected to the notch.
2. The heat exchange plate group connection structure according to claim 1, characterized in that: The notch is a "V-shaped" notch, The "V-shaped" notch includes two inclined edges, and the two edges form an angle less than 180 degrees.
3. The heat exchange plate group connection structure according to claim 1, characterized in that: At least two connecting pieces are provided on one side of the heat exchange plate connected to the pipeline, and the pipeline is provided between the two connecting pieces.
4. The heat exchange plate group connection structure according to claim 1, characterized in that: The cross section of one end of the pipe connected to the heat exchange plate is oblong, and the interface connecting the pipe to the heat exchange plate is oblong.
5. The heat exchange plate group connection structure according to claim 1, characterized in that: The connecting piece is made of "U-shaped" steel; and / or the heat exchange plate is a honeycomb heat exchange plate.
6. The heat exchange plate group connection structure according to claim 1, characterized in that: The pipe is connected to the area of the heat exchange plate that accommodates the heat exchange medium.
7. The heat exchange plate group connection structure according to claim 1, characterized in that: The connecting piece is formed with a plurality of notches along its length, and the notches are clamped to the heat exchange plates. The groove width of the notch is greater than the thickness of the edge region of the heat exchange plate; and / or the groove width of the notch is smaller than the width of the pipe in the plate thickness direction.
8. The heat exchange plate group connection structure according to claim 1, characterized in that: At least one connecting piece is provided on the side of the heat exchange plate connected to the pipeline and on the opposite side thereof.
9. A heat exchanger, characterized in that: The heat exchange plate group connection structure comprises any one of claims 1 to 8, The plurality of heat exchange plates are distributed in parallel along the length direction of the connecting piece. The plurality of pipes are connected to a main pipe so as to pass heat exchange medium into the plurality of heat exchange plates.
10. A heat exchange plate hole expanding device for processing waist-shaped holes on heat exchange plates, characterized in that: The heat exchange plate reaming device includes an operating part, a frame and a drill bit. The frame is used to clamp to both sides of the heat exchange plate. An internal threaded hole is formed on the upper portion of the frame. The operating portion forms an external thread portion, One end of the drill bit forms a waist-shaped portion, The drill bit and the external threaded portion can be at least partially disposed in the internal threaded hole and move axially along the internal threaded hole, and the waist-shaped portion can at least partially extend into the heat exchange plate to expand a waist-shaped hole on the heat exchange plate.