A spiral casing heat exchanger

Abstract

The present invention provides a spiral sleeve heat exchanger, which relates to the technical field of heat exchangers and includes an outer tube, an inner tube, a positioning tube, an arc-shaped side plate, and a heat insulation assembly. The inner tube is located inside the outer tube, and the inner tube and the outer tube form a sleeve heat exchanger structure. One end of the positioning tube penetrates through the outer tube and is fixedly welded to the outer wall of the inner tube, and the positioning tube is fixedly welded to the outer tube. In the present invention, by adopting spiral inner and outer tubes, when the metal temperature difference between the inner and outer coils is large, the inner and outer coils will produce deformations of different sizes. Since there is a large gap between the inner and outer coils, their deformations will not be restricted by each other; and the spiral coil has greater elasticity than a straight tube, which can eliminate most of the temperature difference stress, avoid the use of expansion joints, and thus reduce costs and leakage risks.

Description

Technical Field

[0001] The present invention relates to the technical field of heat exchangers, and particularly to a spiral tube-in-tube heat exchanger. Background Art

[0002] A heat exchanger is a device that transfers heat from one fluid to another without allowing these fluids to mix with each other; currently, there are many types of heat exchangers, such as tube-in-tube heat exchangers, plate heat exchangers, spiral plate heat exchangers, plate and shell heat exchangers, etc.; the tube-in-tube heat exchanger is widely used because of its simple structure, ability to withstand large pressures during operation, and small resistance (pressure drop) to the heat exchange fluid.

[0003] The main structure of the tube-in-tube heat exchanger is that the outer tube sleeves the inner tube, and both ends of the outer tube are welded to the inner tube through tube caps or conical shells, thus forming a set of tube-in-tube; multiple sets of tube-in-tube are connected in series through U-shaped elbows for the inner tubes and in series through pipe orifices for the outer tubes. One of the fluids flows inside the inner tube, and the other fluid flows in the gap between the inner and outer tubes. The two hot and cold fluids exchange heat through the inner tube wall.

[0004] The inventor found the following disadvantages in the conventional tube-in-tube heat exchanger during long-term use:

[0005] 1. Since the inner and outer tubes are long straight tubes, when the metal temperature difference between the inner and outer tubes is large, or when the metal expansion amounts are different due to different materials of the inner and outer tubes, a large temperature difference stress will be generated between the inner and outer tubes; in order to reduce the temperature difference stress, expansion joints are added to the outer tube; the setting of the expansion joints not only increases the cost, but also increases a large number of welded joints, thus increasing the risk of leakage.

[0006] 2. During actual use, the effective heat exchange area is only the part of the inner tube covered by the outer tube, and the parts of the inner tube extending out of the outer tube and the U-shaped elbow parts cannot play a heat transfer role; moreover, in the part between the connection orifice of the outer tubes and the inner and outer tube connectors, the medium flow forms a dead zone, and the heat transfer effect is poor.

[0007] 3. The inner and outer tubes must be welded and connected with tube caps or conical shells, and each set of tube-in-tube must be connected in series with U-shaped elbows, orifices, and flanges. There are many components and connection joints, which not only increases the material and processing costs, but also increases the risk of leakage.

[0008] In order to solve the above technical problems, the present invention provides a spiral tube-in-tube heat exchanger. Summary of the Invention

[0009] In view of the deficiencies of the prior art, the present invention provides a spiral tube-in-tube heat exchanger, which solves the problems of the existing tube-in-tube heat exchanger. Since the inner tube and the outer tube are relatively long straight tubes, when the metal temperature difference between the inner and outer tubes is large, a large temperature difference stress will be generated in the inner and outer tubes, and expansion joints need to be added to the outer tube. Moreover, there are many connecting components and connection joints, which not only increase the cost but also increase the risk of leakage. And for the part between the connection nozzle of the outer tube and the inner and outer tube connecting piece, the medium flow forms a dead zone, resulting in a poor heat transfer effect.

[0010] To achieve the above objectives, the present invention is realized through the following technical solutions: A spiral tube-in-tube heat exchanger, comprising:

[0011] An outer tube and an inner tube, the inner tube is located inside the outer tube, and the inner tube and the outer tube form a tube-in-tube heat exchanger structure. The outer tube and the inner tube are spiral coils with equal spiral radii and equal pitches;

[0012] A positioning tube, one end of the positioning tube penetrates the outer tube, and the positioning tube is welded and fixed to the outer wall of the inner tube, and the positioning tube is welded and fixed to the outer tube;

[0013] An arc-shaped side plate, a positioning hole is provided on the side of the arc-shaped side plate, the positioning tube is fixedly inserted into the positioning hole, and a support seat is fixedly connected to the bottom of the arc-shaped side plate;

[0014] There are multiple positioning tubes, and the multiple positioning tubes are equidistantly distributed along the linear length direction of the outer tube and the inner tube;

[0015] A heat insulation assembly, the tube-in-tube heat exchanger structure is a circular cylinder, and the heat insulation assembly is arranged on the inner side, the outer side and the end of the tube-in-tube heat exchanger structure.

[0016] Further preferably, there are multiple groups of the tube-in-tube heat exchanger structures. The spiral radii of the outer tubes and the inner tubes of the multiple groups of tube-in-tube heat exchanger structures decrease. The multiple groups of tube-in-tube heat exchanger structures are sleeved and distributed from the outside to the inside. The inner tubes of the multiple groups of tube-in-tube heat exchanger structures are linearly connected by a first outer tube connecting pipe, and the annular flow channels of the multiple groups of tube-in-tube heat exchanger structures are linearly connected by a second outer tube connecting pipe;

[0017] The whole formed by multiple groups of tube-in-tube heat exchangers has an A fluid inlet, an A fluid outlet, a B fluid inlet, and a B fluid outlet.

[0018] Further preferably, the heat insulation structure includes:

[0019] An inner cylinder located inside the tube-in-tube heat exchanger structure, and a heat insulation cotton layer is fixedly arranged inside the inner cylinder;

[0020] The outer cylinder located on the outside of the shell-and-tube heat exchanger structure. The top end of the arc-shaped side plate is fixedly connected with a cross brace, and the bottom end of the arc-shaped side plate is fixedly connected with a base. The bottom ends of the outer cylinder and the inner cylinder are both fixedly connected with the base;

[0021] The heat preservation spiral plate, which is attached to the top of the shell-and-tube heat exchanger structure, and the outside of the heat preservation spiral plate is fixedly connected with the outer cylinder, and the inside of the heat preservation spiral plate is fixedly connected with the inner cylinder.

[0022] Further preferably, the base includes: an annular member, a widened portion is provided on the annular member, the top of the widened portion of the annular member is fixedly connected with the bottom end of the arc-shaped side plate, and the bottom of the widened portion of the annular member is fixedly connected with a support leg.

[0023] Further preferably, the heat preservation spiral plate has a spiral angle of 380°-420°, and the heat preservation spiral plate is formed by welding multiple short pieces less than 120°.

[0024] Further preferably, through holes are provided on the side of the outer tube, the outside of the positioning tube is welded to the edge of the through hole to form an outer welding part, and the inside of the positioning tube is welded to the inner tube to form an inner welding part.

[0025] Further preferably, a plug is fixedly installed inside the positioning tube.

[0026] Further preferably, the diameter of the outer tube is 2-3 times the diameter of the inner tube, the diameter of the inner tube is 10-25 CM, and the inner diameter of the positioning tube is not less than 5 CM.

[0027] Further preferably, the first outer tube connecting pipe is U-shaped.

[0028] Further preferably, there are multiple groups of the shell-and-tube heat exchanger structures, the spiral radii of the outer tubes and the inner tubes of the multiple groups of shell-and-tube heat exchanger structures decrease, and the multiple groups of shell-and-tube heat exchanger structures are sleeved and distributed from the outside to the inside;

[0029] Each group of the shell-and-tube heat exchangers has an A fluid inlet, an A fluid outlet, a B fluid inlet, and a B fluid outlet.

[0030] The present invention provides a spiral shell-and-tube heat exchanger. It has the following beneficial effects:

[0031] In the present invention, by adopting spiral inner and outer tubes (i.e., inner and outer coiled tubes), when the metal temperature difference between the inner and outer coiled tubes is relatively large, the inner and outer coiled tubes will generate deformations of different sizes. Since there is a relatively large gap between the inner and outer coiled tubes, their deformations will not be restricted by each other; and the spiral coiled tubes have relatively large elasticity compared to straight tubes and can be used as flexible elements to generate elastic deformations in both horizontal and vertical directions, thereby eliminating most of the temperature difference stress, avoiding the use of expansion joints, and thus reducing costs and leakage risks.

[0032] In the present invention, by adopting a spiral inner tube and an outer tube, both the inner tube and the outer tube can be coiled according to the actual required length, without being restricted by the length of a straight tube. The length of a single spiral coiled tube can be much greater than the length of a single straight tube, and the occupied space is relatively small. Moreover, the entire length range of the spiral tube is an effective heat exchange area, which can greatly increase the heat exchange area per unit installation area.

[0033] Compared with the traditional double-pipe heat exchanger, the spiral double-pipe heat exchanger of the present invention can greatly reduce the connecting elements and joints between the inner and outer tubes, between the inner tubes of each section, and between the outer tubes of each section, reducing both the material and processing costs and the risk of leakage.

[0034] In the present invention, by designing a positioning tube, one end of the positioning tube penetrates through the outer tube and is fixedly welded to the outer wall of the inner tube, and the positioning tube is also fixedly welded to the outer tube. Relying on the positioning tube, the inner tube can be ensured to be basically at the center of the outer tube; after processing the outer tube and the inner tube with a long spiral shape, the inner tube is spirally inserted into the outer tube, and then the positioning tube is welded, so as to ensure the stability of the structure of the spiral double-pipe heat exchanger. When the fluid pressure in the inner tube changes, the inner tube will not shake and cause unstable conditions; moreover, the design of the positioning tube facilitates the overall support and installation of the arc-shaped side plates and the support seats at the bottom.

[0035] In the present invention, by connecting multiple sets of double-pipe heat exchanger structures in parallel / series, the length of the heat exchange pipeline can be further extended to meet the actual heat exchange requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 is the front view of a spiral double-pipe heat exchanger in Embodiment 1 proposed by the present invention;

[0037] Figure 2 is the cross-sectional view of a spiral double-pipe heat exchanger in Embodiment 1 proposed by the present invention;

[0038] Figure 3 is Figure 2 the partial enlarged view at A in

[0039] Figure 4 is the structure of the positioning tube of a spiral double-pipe heat exchanger in Embodiment 1 proposed by the present invention;

[0040] Figure 5 is the perspective view of a spiral double-pipe heat exchanger in Embodiment 2 proposed by the present invention;

[0041] Figure 6 is the cross-sectional view of a spiral double-pipe heat exchanger in Embodiment 2 proposed by the present invention;

[0042] Figure 7Internal perspective three-dimensional schematic diagram of a spiral sleeve heat exchanger in Embodiment 2 proposed by the present invention;

[0043] Figure 8 Internal perspective three-dimensional schematic diagram of a spiral sleeve heat exchanger in Embodiment 2 proposed by the present invention from another angle;

[0044] Figure 9 Three-dimensional schematic diagram of the heat insulation spiral fin plate of a spiral sleeve heat exchanger in Embodiment 2 proposed by the present invention.

[0045] Wherein, 1, arc-shaped side plate; 2, outer tube; 3, positioning tube; 4, support seat; 5, inner tube; 6, positioning hole; 7, outer welding part; 8, inner welding part; 9, plug; 10, A fluid inlet; 11, B fluid outlet; 12, A fluid outlet; 13, B fluid inlet; 14, outer cylinder; 15, inner cylinder; 16, heat insulation cotton layer; 17, cross brace; 18, base; 181, annular part; 182, widened part; 183, support leg; 19, heat insulation spiral fin plate; 20, first outer tube plate connecting pipe; 21, second outer tube plate connecting pipe. Detailed implementation manners

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] Embodiment 1:

[0048] As Figures 1-3As shown in the figure, an embodiment of the present invention provides a spiral sleeve heat exchanger, which includes an outer tube 2, an inner tube 5, a positioning tube 3, an arc-shaped side plate 1, and a heat insulation assembly. The inner tube 5 is located inside the outer tube 2, and the inner tube 5 and the outer tube 2 form a sleeve heat exchanger structure. Specifically, the inner tube 5 is located inside the outer tube 2, and both ends of the inner tube 5 extend from both ends of the outer tube 2. Both ends of the outer tube 2 contract inward and are fixedly connected to the inner tube 5, or both ends of the outer tube 2 are fixedly connected to the outer wall of the inner tube 5 through a connecting joint. An annular flow channel is formed between the outside of the inner tube 5 and the inside of the outer tube 2. Both ends of the inner tube 5 are respectively an A fluid inlet and an A fluid outlet, and both ends of the annular flow channel are respectively a B fluid inlet and a B fluid outlet. The B fluid inlet is close to the A fluid outlet. When in specific use, the A fluid flows from the A fluid inlet to the A fluid outlet, and the B fluid flows from the B fluid inlet to the B fluid outlet. The A fluid and the B fluid flow in opposite directions, and the A fluid and the B fluid exchange heat through the outer wall of the inner tube 5; the outer tube 2 and the inner tube 5 are spiral coiled pipes with equal spiral radii and equal pitches, that is, the outer tube 2 is an outer coiled pipe, and the inner tube 5 is an inner coiled pipe. One end of the positioning tube 3 penetrates the outer tube 2, and the positioning tube 3 is fixedly welded to the outer wall of the inner tube 5, and the positioning tube 3 is fixed to the outer tube 2. The outer tube 2 and the inner tube 5 are fixed by relying on the positioning tube 3 to ensure that the inner tube 5 is in the central position of the outer tube 2. A positioning hole 6 is provided on the side surface of the arc-shaped side plate 1, and the positioning tube 3 is fixedly inserted into the positioning hole 6. A support seat 4 is fixedly connected to the bottom of the arc-shaped side plate 1, and the support seat 4 is used to stably support the arc-shaped side plate 1. A plurality of positioning tubes 3 are provided, and the plurality of positioning tubes 3 are equidistantly distributed along the linear length directions of the outer tube 2 and the inner tube 5. The sleeve heat exchanger structure is an annular cylinder, and the heat insulation assembly is arranged on the inner side, the outer side and the end of the sleeve heat exchanger structure, and the heat insulation assembly is used to insulate the sleeve heat exchanger structure.

[0049] The sleeve heat exchangers used in the chemical industry generally adopt a multi-section straight pipe structure, that is, the outer tube sleeves the inner tube, and both ends of the outer tube are welded to the inner tube through pipe caps or conical shells, thereby forming a set of sleeves; multiple sets of sleeves are connected in series through U-shaped elbows for the inner tubes and in series through pipe orifices for the outer tubes. One of the fluids flows in the inner tube, and the other fluid flows in the gap between the inner and outer tubes. The two cold and hot fluids exchange heat through the inner tube wall. Since the inner tube and the outer tube are relatively long straight pipes, when the metal temperature difference between the inner and outer tubes is relatively large, or due to different materials of the inner and outer tubes, resulting in different metal expansion amounts, a relatively large temperature difference stress will be generated in the inner and outer tubes. In the present invention, by adopting spiral inner and outer tubes (i.e., inner and outer coiled pipes), when the metal temperature difference between the inner and outer coiled pipes is relatively large, the inner and outer coiled pipes will generate different deformations. Since there is a relatively large gap between the inner and outer coiled pipes, their deformations will not be restricted by each other; and the spiral coiled pipes have relatively large elasticity compared to straight pipes and can serve as flexible elements to generate elastic deformations in both the horizontal and vertical directions, thereby eliminating most of the temperature difference stress and avoiding the use of expansion joints, thus reducing costs and leakage risks.

[0050] The inner tube and the outer tube are in a spiral form, enabling the inner tube and the outer tube to be made longer, and the resulting spiral tube heat exchanger has better integrity. In particular, the inner tube is basically a complete seamless pipe, greatly reducing the problem of liquid leakage in the inner tube.

[0051] As Figure 1 shown in Figure 1 , an outer tube 2 and an inner tube 5 with appropriate diameters are selected and processed into spiral coils with the same spiral radius and pitch. Then, the larger-diameter outer spiral coil is sleeved on the smaller-diameter inner spiral coil to form a set of spiral tubes. The two ends of the outer tube 2 are squeezed and contracted by a hydraulic die, and the end of the outer tube 2 is welded and fixed to the inner tube 5. Then, holes are opened at positions near both ends on the outer side of the outer tube 2 to connect the inlet / outlet liquid pipes, forming a B-fluid inlet and a B-fluid outlet. The two ends of the inner tube 5 are an A-fluid inlet and an A-fluid outlet. Then, mounting holes for mounting the positioning tube 3 are opened on the side of the outer tube 2. One end of the positioning tube 3 is inserted into the mounting hole, and one end of the positioning tube 3 abuts against the side of the inner tube 5. Laser welding is performed from the inside of the inner tube 5 to weld and fix the inner tube 5 and the positioning tube 3. Finally, on the outer side of the positioning tube 3, laser welding is completed at the mounting hole of the positioning tube 3 and the outer tube 2. The positioning tube 3 is used to fix the outer tube 2 and the inner tube 5 together.

[0052] Specifically, through holes (mounting holes) are opened on the side of the outer tube 2, and the outer side of the positioning tube 3 is welded to the edge of the through hole to form an outer welding part 7, and the inner side of the positioning tube 3 is welded to the inner tube 5 to form an inner welding part 8.

[0053] One way is as follows: The B-fluid is the liquid to be heated, and the A-fluid is the heat supply fluid. To ensure efficient and stable supply of the B-fluid that meets the temperature requirements, it is necessary to design a relatively large cross-sectional area of the annular flow channel and a relatively large liquid flow velocity in the annular flow channel. However, the problems brought about by a relatively large cross-sectional area of the annular flow channel and a relatively large liquid flow velocity in the annular flow channel are that the actual heat exchange efficiency of the fluid is relatively low, and the problem brought about by a relatively large cross-sectional area of the annular flow channel is that the liquid near the outer side of the outer tube 2 cannot have good heat exchange. The design of the spiral tube heat exchanger enables the B-fluid to be turbulent inside the annular flow channel, ensuring uniform heat exchange of the B-fluid; the design of the spiral tube heat exchanger increases the heat exchange time of the B-fluid in the annular flow channel, ensuring that the B-fluid can be heated to the predetermined temperature.

[0054] Specifically, the diameter of the outer tube 2 is 2 - 3 times the diameter of the inner tube 5. There is a large space between the inner tube 5 and the outer tube 2, which can provide a relatively large fluid cross-section. The diameter of the inner tube 5 is 10 - 25 cm, and the inner diameter of the positioning tube 3 is not less than 5 cm, enabling the laser head to be inserted into the positioning tube 3 to complete the welding operation.

[0055] In one embodiment, a blocking block 9 is fixedly installed inside the positioning pipe 3. Due to the influence of space, the welding quality of the welded joint between the positioning pipe 3 and the inner pipe 5 may not be good. By using the blocking block 9 to block the inside of the positioning pipe 3, it is possible to prevent liquid from seeping into the positioning pipe 3 and then causing leakage.

[0056] Embodiment Two:

[0057] Reference appendix Figures 5-9 The difference from the above Embodiment One is as follows: There are multiple sets of shell-and-tube heat exchanger structures. The spiral radii of the outer tubes 2 and the inner tubes 5 of the multiple sets of shell-and-tube heat exchanger structures decrease. The multiple sets of shell-and-tube heat exchanger structures are sleeved and distributed from the outside to the inside. The inner tubes 5 of the multiple sets of shell-and-tube heat exchanger structures are linearly connected through the first outer tube disk connecting pipe 20, and the annular flow channels of the multiple sets of shell-and-tube heat exchanger structures are linearly connected through the second outer tube disk connecting pipe 21. The multiple shell-and-tube heat exchanger structures distributed in the above manner can make better use of space and can further extend the length of the actual heat exchange pipeline. In the overall structure composed of multiple shell-and-tube heat exchangers, there are an A fluid inlet 10, an A fluid outlet 12, a B fluid inlet 13, and a B fluid outlet 11. The first outer tube disk connecting pipe 20 is U-shaped.

[0058] That is, the multiple sets of shell-and-tube heat exchanger structures are connected in series, which can further extend the length of the actual heat exchange pipeline.

[0059] Embodiment Three:

[0060] The difference from the above Embodiment One is as follows: There are multiple sets of shell-and-tube heat exchanger structures. The spiral radii of the outer tubes and the inner tubes of the multiple sets of shell-and-tube heat exchanger structures decrease. The multiple sets of shell-and-tube heat exchanger structures are sleeved and distributed from the outside to the inside. The multiple shell-and-tube heat exchanger structures distributed in the above manner can make better use of space; each set of shell-and-tube heat exchanger has an A fluid inlet, an A fluid outlet, a B fluid inlet, and a B fluid outlet.

[0061] That is, the multiple sets of shell-and-tube heat exchanger structures are connected in parallel (not shown in the drawings), which can simultaneously achieve the heat exchange of multiple fluids, thereby enabling the stable supply of fluids.

[0062] Specifically, the heat insulation structure includes: an inner cylinder 15 located inside the shell-and-tube heat exchanger structure, an outer cylinder 14 located outside the shell-and-tube heat exchanger structure, and a heat insulation spiral plate 19.

[0063] A heat preservation cotton layer 16 is fixedly arranged on the inner side of the inner cylinder 15. The heat preservation cotton layer 16 is used to increase the heat preservation performance of the inner cylinder 15. A cross brace 17 is fixedly connected to the top end of the arc-shaped side plate 1. The cross brace 17 is used to connect multiple arc-shaped side plates 1. A base 18 is fixedly connected to the bottom end of the arc-shaped side plate 1. The base 18 plays a supporting role. The bottom ends of the outer cylinder 14 and the inner cylinder 15 are both fixedly connected to the base 18. The heat preservation spiral plate 19 is attached to the top end of the shell-and-tube heat exchanger structure, and the outer side of the heat preservation spiral plate 19 is fixedly connected to the outer cylinder 14, and the inner side of the heat preservation spiral plate 19 is fixedly connected to the inner cylinder 15.

[0064] In this solution, the heat preservation spiral plate 19, the inner cylinder 15, and the outer cylinder 14 form an annular space, and the annular body formed by multiple shell-and-tube heat exchanger structures is located inside the annular space, so as to achieve the heat preservation effect.

[0065] In one embodiment, the base 18 includes: an annular member 181, a widened portion 182 is arranged on the annular member 181, the widened portion 182 can connect multiple arc-shaped side plates 1, the top of the widened portion 182 of the annular member 181 is fixedly connected to the bottom end of the arc-shaped side plate 1, and a support foot 183 is fixedly connected to the bottom of the widened portion 182 of the annular member 181.

[0066] In one embodiment, the heat preservation spiral plate 19 has a spiral angle of 380° - 420°. Generally, the heat preservation spiral plate 19 should be greater than 360°. The heat preservation spiral plate 19 is formed by welding multiple short plates with an angle less than 120°. The multiple short plates with an angle less than 120° are convenient for installation. After the installation positions are aligned, they are welded and fixed to form the heat preservation spiral plate 19.

[0067] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A spiral tube-type heat exchanger, comprising an outer tube (2) and an inner tube (5), wherein the inner tube (5) is located inside the outer tube (2), and the inner tube (5) and the outer tube (2) form a tube-type heat exchanger structure, characterized in that: The outer tube (2) and the inner tube (5) are spiral coils with equal spiral radius and equal spiral pitch, and further include: A positioning tube (3), one end of which passes through the outer tube (2), and the positioning tube (3) is fixed to the outer wall of the inner tube (5) by welding, and the positioning tube (3) is fixed to the outer tube (2) by welding; An arc-shaped side plate (1), wherein a positioning hole (6) is provided on a side surface of the arc-shaped side plate (1), the positioning tube (3) is fixedly inserted into the positioning hole (6), and a support seat (4) is fixedly connected to the bottom of the arc-shaped side plate (1); A plurality of the positioning tubes (3) are provided, and the plurality of the positioning tubes (3) are equidistantly distributed along the linear length direction of the outer tube (2) and the inner tube (5); The heat preservation component is an annular cylindrical structure of the shell and tube heat exchanger, and the heat preservation component is arranged on the inner side, the outer side and the end of the shell and tube heat exchanger structure.

2. A spiral tube heat exchanger according to claim 1, characterized in that: The shell-and-tube heat exchanger structure comprises a plurality of groups, the spiral radii of the outer tubes (2) and the inner tubes (5) of the plurality of groups of shell-and-tube heat exchanger structures decrease gradually, the plurality of groups of shell-and-tube heat exchanger structures are arranged in a shell-and-tube arrangement from the outside to the inside, the plurality of groups of inner tubes (5) of the shell-and-tube heat exchanger structures are linearly connected via a first outer tube coil connecting tube (20), and the plurality of groups of annular flow passages of the shell-and-tube heat exchanger structures are linearly connected via a second outer tube coil connecting tube (21); The whole formed by multiple sets of shell-and-tube heat exchangers has an A fluid inlet (10), an A fluid outlet (12), a B fluid inlet (13), and a B fluid outlet (11).

3. The spiral tube heat exchanger according to claim 2, characterized in that: The thermal insulation component comprises: An inner cylinder (15) located inside the shell-and-tube heat exchanger structure, a heat-insulating cotton layer (16) being fixedly disposed inside the inner cylinder (15); An outer cylinder (14) located outside the shell-and-tube heat exchanger structure, the top end of the arc-shaped side plate (1) is fixedly connected to a cross brace (17), the bottom end of the arc-shaped side plate (1) is fixedly connected to a base (18), and the bottom ends of the outer cylinder (14) and the inner cylinder (15) are both fixedly connected to the base (18); The thermal insulation spiral fin plate (19) is attached to the top of the shell-and-tube heat exchanger structure, and the outer side of the thermal insulation spiral fin plate (19) is fixedly connected to the outer cylinder (14), and the inner side of the thermal insulation spiral fin plate (19) is fixedly connected to the inner cylinder (15).

4. The spiral tube heat exchanger according to claim 3, characterized in that: The base (18) comprises: an annular member (181), the annular member (181) being provided with a widened portion (182), the top of the widened portion (182) of the annular member (181) being fixedly connected to the bottom end of the arc-shaped side plate (1), and the bottom of the widened portion (182) of the annular member (181) being fixedly connected to a supporting foot (183).

5. The spiral tube heat exchanger according to claim 3, characterized in that: The heat-insulating spiral sheet plate (19) has a spiral angle of 380°-420°, and the heat-insulating spiral sheet plate (19) is welded from a plurality of groups of short sheets with an angle less than 120°.

6. The spiral tube heat exchanger according to claim 1, characterized in that: A through hole is provided on the side of the outer tube (2), the outer side of the positioning tube (3) is welded to the edge of the through hole to form an outer welding portion (7), and the inner side of the positioning tube (3) is welded to the inner tube (5) to form an inner welding portion (8).

7. The spiral tube heat exchanger according to claim 6, characterized in that: A blocking block (9) is fixedly installed inside the positioning tube (3).

8. The spiral tube heat exchanger according to claim 1, characterized in that: The diameter of the outer tube (2) is 2-3 times the diameter of the inner tube (5), the diameter of the inner tube (5) is 10-25 cm, and the inner diameter of the positioning tube (3) is not less than 5 cm.

9. The spiral tube heat exchanger according to claim 2, characterized in that: The first outer tube disc connecting pipe (20) is U-shaped.

10. The spiral tube heat exchanger according to claim 1, characterized in that: The shell-and-tube heat exchanger structure comprises a plurality of groups, wherein the spiral radii of the outer tubes (2) and the inner tubes (5) of the plurality of groups of shell-and-tube heat exchanger structures decrease gradually, and the plurality of groups of shell-and-tube heat exchanger structures are arranged in a shell-and-tube arrangement from the outside to the inside; Each group of the shell-and-tube heat exchangers has an A fluid inlet (10), an A fluid outlet (12), a B fluid inlet (13), and a B fluid outlet (11).

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