Air-cooled heat exchanger and assembly method

Abstract

The present invention discloses an air-cooled heat exchanger and an assembly method, and relates to the technical field of heat exchange equipment. The air-cooled heat exchanger includes: a plurality of flat tube-type finned tubes, a fixed tube box, a floating tube box, two tube sheets and an outer shell, wherein the outer surface of the base tube of the finned tube is connected to the fin by brazing; the two ends of the finned tube are respectively inserted into the tube holes on the two tube sheets to form a fixed joint; the gap between the base tube and the outer side of the tube hole forms a glue-sealed joint; the inside of the base tube is divided into two tube passes; the two tube sheets are respectively fixedly connected to the fixed tube box and the floating tube box; the outer shell wraps and supports the flat tube-type finned tube, the tube sheet, the fixed tube box and the floating tube box; the fixed tube box is provided with a tube pass partition, a process fluid inlet and a process fluid outlet; the tube pass partition is fixedly connected to one end of the finned tube. The air-cooled heat exchanger realizes the tube pass separation structure of the finned tube body, which fully meets the requirements of long-term operation stability of the equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchange equipment, and in particular to a heat exchanger for an air cooling system and an assembly method thereof. Background Art

[0002] At present, most of the indirect air-cooled heat exchangers in thermal power plants adopt the aluminum tube sleeve aluminum fin type. There are many round holes and slits on the fins of the heat exchanger. After stamping, they are set one by one on multiple circular base tubes to form fin tube units. Several groups of fin tube units are arranged in parallel to form a tube bundle. On the one hand, the tube bundle composed of several groups of fin tube units in parallel generally has two tube passes, and the two tube passes are separated by multiple rows of fin tubes. This existing tube pass structure will cause the temperature field of the air-cooled heat exchanger to be discontinuous (intermittent); on the other hand, the tube bundle is connected to the base tube and the root of the fin by the expansion method, and then the surface chemical treatment is performed to enhance the corrosion resistance. The tube end of the base tube and the connection plate joint adopt the rubber ring sealing type after expansion, and then several groups of tube bundles are connected in series, and the two ends are connected to the pipe box respectively. After expansion and sealing with rubber rings, the outer shell is installed to form a complete heat exchanger structure. In the existing heat exchanger, under the influence of frequent thermal expansion and contraction, the expansion connection structure between the fin and the base tube is easily damaged, which affects the use effect of the heat exchanger. In addition, the antifreeze performance of the circular base tube is poor. Summary of the invention

[0003] In view of this, the present invention provides an air-cooled heat exchanger and an assembly method, providing a finned tube with multiple channels. At the same time, the fins of the finned tube are connected to the base tube by brazing and the tube-side separation structure is realized on the finned tube body, which fully meets the requirements of long-term operation stability of the equipment and obtains obvious economic benefits.

[0004] To achieve the above object, one aspect of the present invention provides an air-cooled heat exchanger, comprising: a plurality of flat tube-type finned tubes arranged in parallel in a single row, a fixed tube box, a floating tube box, two tube sheets disposed at both ends of the plurality of flat tube-type finned tubes, and a shell, wherein:

[0005] The fin tube comprises a base tube and fins, and the outer surface of the base tube and the fins are connected by brazing;

[0006] The two ends of the fin tube are respectively inserted into the tube holes on the two tube sheets to form a fixed joint; the gap between the base tube and the outer side of the tube hole forms a glue-sealed joint;

[0007] The interior of the base tube is divided into two tube passes;

[0008] The two tube sheets are fixedly connected to the fixed tube box and the floating tube box respectively;

[0009] The shell wraps and supports the flat tube type fin tube, the tube sheet, and the connection structure formed by the fixed tube box and the floating tube box;

[0010] The fixed pipe box is provided with a pipe-side partition, a process fluid inlet and a process fluid outlet;

[0011] The tube-pass partition is fixedly connected to one end of the fin tube, so that the front end of the tube pass of the fin tube is connected to the process fluid inlet, and the end of the other tube pass is connected to the process fluid outlet.

[0012] Optionally, the base pipe is provided with pipe-side vertical ribs and auxiliary vertical ribs arranged on both sides of the pipe-side vertical ribs, wherein:

[0013] One end of the tube side vertical rib is fixedly connected to the tube side partition plate, and is used to divide the inside of the base tube into two tube sides;

[0014] The auxiliary vertical ribs are used to divide the pipe path into a plurality of mutually parallel rectangular channels.

[0015] Optionally, the base tube is a flat-mouth structure formed by processing an aluminum alloy material by a hot extrusion and stretching process, wherein an end of the flat-mouth structure is an arc-shaped structure.

[0016] Optionally, the surface of the fin is rolled with concave-convex patterns;

[0017] and / or,

[0018] The cross-sectional dimension of the fin is within the range of (190-210)╳(19-39) mm, the spacing between adjacent middle fins is within the range of 2-3.5 mm, and the thickness of the fin material is within the range of 0.2-0.3 mm.

[0019] Optionally, the thickness of the auxiliary ribs is in the range of 0.6 to 1 mm, and the thickness of the tube-side ribs is in the range of 8 to 10 mm.

[0020] Optionally, one side of the shell is fixedly connected to a tube sheet to which the fixed tube box is connected;

[0021] The other side of the shell is in floating connection with the tube sheet to which the floating tube box is connected.

[0022] In a second aspect, the present invention provides an assembly method of the above-mentioned air-cooled heat exchanger, comprising:

[0023] Inserting one end of a plurality of fin tubes into a plurality of tube holes of a tube sheet correspondingly, and welding and sealingly connecting one end of the fin tube to the tube hole;

[0024] Inserting the other ends of the plurality of fin tubes into the plurality of tube holes of another tube sheet, and welding and sealing the other ends of the fin tubes with the tube holes of another tube sheet;

[0025] The tube-side partition in the fixed tube box is welded to the tube-side vertical ribs in the plurality of fin tubes, and the fixed box body of the fixed tube box is welded to the tube-side partition and the tube sheet;

[0026] Welding the tube sheet on the floating side to the floating box;

[0027] One side of the shell is fixedly connected to the tube sheet on the fixed side by bolts, and the other side of the shell is floatingly connected to the tube sheet on the floating side by floating bolts along the length direction of the tube bundle;

[0028] The gap formed on one side of the tube hole close to the fin tube is sealed.

[0029] The technical solution provided by the present invention has the following advantages or beneficial effects: because the fins of the finned tube are connected to the base tube by brazing, the rigidity of the finned tube is improved, so that the finned tube has enhanced ability to resist external impact; secondly, the tube separation structure of the single-row finned tube body can effectively solve the problem of discontinuity (interruption) of the temperature field caused by the external separation of the multi-row finned tubes in the traditional technology; thirdly, the flat-mouthed base tube structure has expansion margin, which improves the antifreeze performance of the finned tube; and the entire processing process omits the surface chemical treatment process, and no environmental pollution occurs. These fully meet the needs of long-term operation stability of the equipment and achieve obvious economic benefits.

[0030] The further effects of the above non-conventional optional manner will be described below in conjunction with specific implementations. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0032] Figure 1 is a schematic diagram of the three-dimensional structure of an air-cooled heat exchanger according to an embodiment of the present invention;

[0033] Figure 2 The present invention Figure 1 A schematic diagram of the transverse cross-sectional structure of an air-cooled heat exchanger of an embodiment;

[0034] Figure 3 The present invention Figure 1 A schematic diagram of the longitudinal cross-sectional structure of an air-cooled heat exchanger of an embodiment;

[0035] Figure 4 Embodiment of the present invention Figure 2 An enlarged schematic diagram of region A;

[0036] Figure 5 is a schematic cross-sectional view of a base pipe according to an embodiment of the present invention;

[0037] Figure 6 is a schematic cross-sectional view of a fin according to an embodiment of the present invention;

[0038] Figure 7 It is a schematic diagram of the main process of the assembly method of the air-cooled heat exchanger according to an embodiment of the present invention.

[0039] The reference numerals are as follows:

[0040] 1- fin tube; 11- base tube; 111- tube side ribs; 112- auxiliary ribs; 12- fins; 121- middle piece; 122- connector; 123- single air duct; 124- concave-convex texture

[0041] 2-fixed pipe box; 21-fixed box body; 22-pipeline partition; 23-process fluid inlet; 24-process fluid outlet

[0042] 3- floating pipe box; 31- floating box

[0043] 4-tube sheet; 41-tube hole

[0044] 5- Shell

[0045] 501-fixed bolt; 502-floating bolt

[0046] 601-Pipe end welding joint

[0047] 701-Rectangular channel

[0048] 801-Glue seal joint

[0049] 901-Air DETAILED DESCRIPTION

[0050] Embodiments of the present invention are described below in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding. They should be considered as merely exemplary. Therefore, it should be appreciated by those skilled in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0051] Figure 1 The three-dimensional structure of the air-cooled heat exchanger provided by the embodiment of the present invention is shown. Figure 2 Shows Figure 1 A schematic cross-sectional view of the structure shown. Figure 3 Shows Figure 1 A schematic diagram of the longitudinal section of the structure shown. Figures 1 to 3As shown, the air-cooled heat exchanger comprises: a plurality of flat tube-type finned tubes 1 arranged in a single row, a fixed tube box 2, a floating tube box 3, two tube sheets 4 arranged at both ends of the plurality of flat tube-type finned tubes 1, and a shell 5, wherein:

[0052] The fin tube 1 comprises a base tube 11 and fins 12. The outer surface of the base tube 11 and the fins 12 are connected by brazing. The two ends of the fin tube 1 are respectively inserted into the tube holes 41 on the two tube sheets 4 to form a fixed joint 601. The gap between the base tube 11 and the outer side of the tube hole 41 forms a glue-sealed joint 801. The base tube 11 is divided into two tube passes. The two tube sheets 4 are respectively fixedly connected to the fixed tube box 2 and the floating tube box 3. The shell 5 wraps and supports the connection structure formed by the flat tube fin tube 1, the tube sheet 4, and the fixed tube box 2 and the floating tube box 3. The fixed tube box 2 is provided with a tube pass partition 22, a process fluid inlet 23 and a process fluid outlet 24. The tube pass partition 22 is fixedly connected to one end of the fin tube 1 so that the frontmost tube pass of the fin tube 1 is connected to the process fluid inlet 23, and the end of the other tube passes is connected to the process fluid outlet 24. Among them, the air 901 passes through the fins from bottom to top to take away the heat dissipated by the fluid in the base tube.

[0053] Among them, from Figure 1 The air-cooled heat exchanger structure shown and Figure 4 shown Figure 2 It can be seen from the enlarged structure of the marked A area that after the end of the fin tube 1 passes through the tube hole 41, it is welded to the surrounding of the tube hole 41 to form a tube end welding joint 601, and the gap between the base tube 11 and the outer tube hole 41 is filled with sealant to form a sealant joint 801, which can achieve sealing and fixation between the fin tube 1 and the tube sheet 4.

[0054] Among them, the base tube and the fin connected by the prior art through the expansion method have poor reliability of connection between the base tube and the fin under the influence of frequent thermal expansion and contraction. Compared with the prior art, the outer surface of the base tube 11 and the fin 12 in the embodiment of the present invention are connected by brazing, which can effectively solve the problem of poor reliability of connection between the base tube and the fin. Moreover, the outer surface of the base tube 11 and the fin 12 are connected by the brazing process, and there is no gap thermal resistance.

[0055] In addition, the fin tube 1 in the air-cooled heat exchanger provided in the embodiment of the present invention is made of all-aluminum and has good thermal conductivity, forming and corrosion resistance.

[0056] In the embodiment of the present invention, Figure 3 The longitudinal cross-sectional diagram of the air-cooled heat exchanger shown in FIG. Figure 5It can be seen from the schematic cross-sectional view of the base tube shown that a tube-side rib 111 and auxiliary ribs 112 arranged on both sides of the tube-side rib 111 are provided inside the base tube 11 in the air-cooled heat exchanger, wherein one end of the tube-side rib 111 is fixedly connected to the tube-side partition 22 for dividing the inside of the base tube 11 into two tube-sides; the auxiliary ribs 112 are used to divide the tube-side into a plurality of mutually parallel rectangular channels 701.

[0057] The base tube can be divided into different tube passes and multiple parallel channels can be divided in the corresponding tube passes by the tube pass ribs 111 and the auxiliary ribs 112 arranged on both sides of the tube pass ribs 111, making the tube passes and process fluid channels more compact. In addition, the heat exchange effect can be enhanced by dividing the inside of the base tube 11 into multiple mutually parallel rectangular channels 701; the tube pass ribs 111 and the tube pass partitions 22 directly divide the tube passes on the fin tube 1 body, so that the temperature field of the fluid inside and outside the tube is evenly distributed and continuous, and the thermal performance is significantly improved.

[0058] It is worth noting that the number of the above-mentioned tube-pass vertical ribs 111 can be multiple, so as to divide the inside of the base tube 11 into multiple tube passes.

[0059] In the embodiment of the present invention, the base tube 11 is a flat-mouth structure formed by hot extrusion and stretching of aluminum alloy material, wherein Figure 5 As shown, the end of the flat-mouth structure is an arc-shaped structure.

[0060] In the embodiment of the present invention, Figure 6 As shown, the fins 12 in the air-cooled heat exchanger tube bundle include a plurality of intermediate sheets 121 and a plurality of connectors 122, wherein: the plurality of intermediate sheets 121 are arranged in parallel side by side, and a plurality of adjacent intermediate sheets 121 are connected to each other through a plurality of connectors 122. The connector 122 is a semicircular arc structure, and the two ends of the connector 122 are respectively connected to the ends of the adjacent intermediate sheets 121, and the tangent of the connector 122 at the connection point passes through the ends of the adjacent intermediate sheets 121. In addition, the surface of the fin 12 is rolled with concave-convex patterns 124, which can enhance the heat exchange effect. The two ends of the adjacent intermediate sheets 121 are connected by the connector 122 of the semicircular arc structure, and a single ventilation duct 123 is formed between the adjacent intermediate sheets, which is not easy to stick to inclusions in the air and is easy to clean with high-pressure water. The heat exchange process is not affected by the change in the flow direction of the air outside the tube, and the air resistance is small and the performance is stable.

[0061] In addition, the fin 12 is generally made of composite aluminum alloy material 3003 / 4343, and is formed by rolling an aluminum strip.

[0062] In the embodiment of the present invention, the cross-sectional dimension of the fin 12 is in the range of (190-210)╳(19-39) mm, the spacing between adjacent intermediate fins is in the range of 2-3.5 mm, and the material thickness of the fin 12 is in the range of 0.2-0.3 mm.

[0063] In the embodiment of the present invention, the cross-sectional dimension of the base tube 11 is in the range of (209-229)×19 ​​mm, and the tube wall thickness is in the range of 1-1.6 mm.

[0064] In the embodiment of the present invention, the thickness of the pipe-side vertical ribs 111 is in the range of 8 to 10 mm, and the thickness of the auxiliary vertical ribs 112 is in the range of 0.6 to 1 mm.

[0065] In the embodiment of the present invention, one side of the shell 5 is fixedly connected to the tube sheet 4 connected to the fixed tube box 2; the other side of the shell 5 is floatingly connected to the tube sheet 4 connected to the floating tube box 3.

[0066] Among them, Figure 1 and Figure 2 As shown, one side of the housing 5 can be fixedly connected to the tube sheet 4 connected to the fixed tube box 2 through a fixing bolt 501; the other side of the housing 5 can be floatingly connected to the tube sheet 4 connected to the floating tube box 3 through a floating bolt 502. It is worth noting that the floating connection can make the floating tube box 3 and the tube sheet 4 connected to the floating tube box 3 move freely in the length direction of the base tube 11 to adapt to the thermal expansion and contraction of the fin tube, while being fixed in other directions of the base tube 11. The floating connection method can better meet the expansion and contraction requirements of the base tube during use, and effectively prevent the damage of the fin tube caused by expansion and contraction during use.

[0067] In addition, the fixed pipe box 2 (with a process fluid inlet 23 and a process fluid outlet 24) and the floating pipe box 3 are all made of aluminum, and the material is high-strength aluminum alloy 6061. The whole structure is welded, and the welding joint adopts the melting pole MIG process method. In this embodiment, the fixed box body 21 of the fixed pipe box 2 has a rectangular cross-section, and the floating box body 31 of the floating pipe box 3 has a semicircular cross-section. The wall thickness of the fixed box body 21 of the fixed pipe box 2 and the floating box body 31 of the floating pipe box 3 is determined to be 12mm according to the internal fluid pressure through design calculation. The thickness of the tube sheet 4 is within the range of 16 to 36mm. The single-row parallel flat-mouthed tube holes 41 opened on the tube sheet 4 can be formed by mechanical cutting method; the tube hole 41 is welded with the end of the inserted base pipe 11 to form a welding joint 601, and the welding process is selected as the non-melting pole TIG method. To ensure the welding quality, the opening gap between the base tube 11 and the tube hole 41 can be in the range of 0.4 to 0.8 mm. After the base tube 11 is inserted into the tube sheet 4, the tube head protrusion is in the range of 1 to 4 mm. In a preferred embodiment, the tube head protrusion is 3 mm. The tube side partition 22 is directly welded to the tube side vertical rib 111, and the structure is compact, simple and uncomplicated.

[0068] In addition, the outer side sealing joint 801 between the base pipe 11 and the pipe hole 41 can be blown with PES polyester hot melt adhesive to achieve sealing and anti-corrosion effects.

[0069] The main structure of the housing 5 is made of high-strength aluminum alloy material, and the connecting parts such as fixing bolts, floating bolts, etc. can be made of stainless steel or hot-dip galvanized material.

[0070] Figure 7 Schematic diagram of the main process of the assembly method of the air-cooled heat exchanger according to the embodiment of the present invention. Figure 7 As shown, the assembly method of the air-cooled heat exchanger of the present invention comprises the following steps:

[0071] Step S1, inserting one end of a plurality of fin tubes into a plurality of tube holes of a tube sheet correspondingly, and welding one end of the fin tube to the tube hole for sealing connection;

[0072] Step S2, inserting the other ends of the plurality of fin tubes into the plurality of tube holes of another tube sheet, and welding and sealing the other ends of the fin tubes with the tube holes of another tube sheet;

[0073] Step S3, welding and connecting the tube-side partition in the fixed tube box to the tube-side vertical ribs in the plurality of fin tubes, and welding and connecting the fixed box body of the fixed tube box to the tube-side partition and the tube sheet;

[0074] Step S4, welding the floating side tube sheet to the floating box;

[0075] Step S5, fixing one side of the shell with the fixed side tube sheet by fixing bolts, and floatingly connecting the other side of the shell with the floating side tube sheet by floating bolts along the length direction of the tube bundle;

[0076] Step S6, sealing the gap formed on one side of the tube hole close to the fin tube.

[0077] It is worth noting that in the embodiment of the present invention, a welded joint is formed by welding the connected parts, and the welding method can be but is not limited to the following welding methods: such as MIG melting inert gas shielded welding, TIG non-melting inert gas shielded welding, manual arc welding or laser feeding inert gas shielded welding, etc.

[0078] The air-cooled heat exchanger provided by the technical solution of the embodiment of the present invention has a compact structure, a small number of parts, low operating costs, a simple welding joint structure, and a simplified processing technology; while reducing processing costs, it can also increase the qualified rate of finished products and improve the performance of equipment; the main components are made of aluminum, which extends the service life of the air-cooling system; through hot melt adhesive blowing and sealing, the anti-corrosion sealing performance of the equipment is improved, ensuring long-term use effects.

[0079] The fin tubes, fixed tube boxes, floating tube boxes, shells and other components of the present invention are made of all-aluminum material and / or all-aluminum structure, so that the weight of the heat exchanger is reduced; accordingly, the supporting structure and civil engineering scale of the heat exchanger are reduced, the structure is simplified, and the overall cost of the air cooling system is reduced.

[0080] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An air-cooled heat exchanger, characterized in that: include: A plurality of flat tube-type finned tubes (1) arranged in parallel in a single row, a fixed tube box (2), a floating tube box (3), two tube sheets (4) arranged at both ends of the plurality of flat tube-type finned tubes (1), and a shell (5), wherein: The fin tube (1) comprises a base tube (11) and fins (12), and the outer surface of the base tube (11) and the fins (12) are connected to each other by brazing; The two ends of the fin tube (1) are respectively inserted into the tube holes (41) on the two tube sheets (4) to form a fixed joint (601); the gap between the base tube (11) and the outside of the tube hole (41) forms a glue-sealed joint (801); The base tube (11) is internally divided into two tube passes; The two tube sheets (4) are fixedly connected to the fixed tube box (2) and the floating tube box (3) respectively; The shell (5) wraps and supports the flat tube type fin tube (1), the tube sheet (4), and the connection structure formed by the fixed tube box (2) and the floating tube box (3); The fixed pipe box (2) is provided with a pipe-side partition (22), a process fluid inlet (23) and a process fluid outlet (24); The tube side partition (22) is fixedly connected to one end of the fin tube (1), so that the front end of the tube side of the fin tube (1) is connected to the process fluid inlet (23), and the end of the other tube side is connected to the process fluid outlet (24); The base pipe (11) is provided with pipe-side vertical ribs (111) and auxiliary vertical ribs (112) arranged on both sides of the pipe-side vertical ribs (111), wherein: One end of the tube side vertical rib (111) is fixedly connected to the tube side partition (22) and is used to divide the interior of the base tube (11) into two tube sides; The auxiliary vertical ribs (112) are used to divide the pipe into a plurality of mutually parallel rectangular channels (701); One side of the shell (5) is fixedly connected to a tube sheet (4) to which the fixed tube box (2) is connected; The other side of the shell (5) is in floating connection with the tube sheet (4) to which the floating tube box (3) is connected.

2. The air-cooled heat exchanger according to claim 1, characterized in that: The base tube (11) is a flat-mouth structure formed by processing an aluminum alloy material by a hot extrusion and stretching process, wherein the end of the flat-mouth structure is an arc-shaped structure.

3. The air-cooled heat exchanger according to claim 1, characterized in that: The surface of the fin (12) is rolled with concave-convex patterns (124); and / or, The cross-sectional dimensions of the fin (12) are within the range of (190-210)×(19-39) mm, the spacing between adjacent intermediate fins (121) of the fin is within the range of 2-3.5 mm, and the thickness of the material of the fin (12) is within the range of 0.2-0.3 mm.

4. The air-cooled heat exchanger according to claim 1, characterized in that: The thickness of the auxiliary vertical ribs (112) is in the range of 0.6 to 1 mm, and the thickness of the tube-side vertical ribs (111) is in the range of 8 to 10 mm.

5. A method for assembling an air-cooled heat exchanger according to any one of claims 1 to 4, characterized in that: include: Inserting one end of a plurality of fin tubes (1) into a plurality of tube holes (41) of a tube sheet (4) respectively, and welding one end of the fin tube (1) to the tube hole (41) to seal the connection; Inserting the other ends of the plurality of fin tubes (1) into the plurality of tube holes (41) of another tube sheet (4), and welding the other ends of the fin tubes (1) to the tube holes (41) of another tube sheet (4) for sealing connection; The tube-side partition (22) in the fixed tube box (2) is welded to the tube-side vertical ribs (111) in the plurality of fin tubes (1), and the fixed box body (21) of the fixed tube box (2) is welded to the tube-side partition (22) and the tube sheet (4); The tube sheet (4) on the floating side is welded to the floating box (31); One side of the shell (5) is fixedly connected to the tube sheet (4) on the fixed side by means of bolts, and the other side of the shell (5) is floatingly connected to the tube sheet (4) on the floating side by means of floating bolts along the length direction of the tube bundle; The gap formed on one side of the tube hole (41) close to the fin tube (1) is sealed.

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