A spiral finned tube heat exchanger

Abstract

The application discloses a spiral finned tube heat exchanger, and relates to the application field of heat exchangers, which comprises a box body, a heat exchanger assembly is arranged in the box body, the heat exchanger assembly comprises multiple groups of heat exchange tubes which are staggered, the heat exchange tube comprises a base pipe and an outer spiral fin, an inner spiral fin is arranged in the base pipe, a dust cleaning assembly is arranged above the multiple groups of heat exchange tubes of the heat exchanger assembly, and the dust cleaning assembly is driven by water flow in a water tank. The inner spiral fin is arranged in the base pipe, the spiral distribution tracks of the outer spiral fin and the inner spiral fin are the same, the distance between the fin root of the outer spiral fin and the outer edge of the inner spiral fin is the shortest in the heat transfer path, when high-temperature flue gas transfers heat to the outer spiral fin, the heat can be transferred to the inner spiral fin through the shortest heat transfer path, the contact area between the inner spiral fin and the cold medium is larger, and therefore the heat transfer efficiency between the flue gas and the cold medium can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heat exchangers, in particular to a spiral finned tube heat exchanger. BACKGROUND

[0002] A flue gas heat exchanger (also known as a flue gas waste heat exchanger) is a core energy-saving device for recovering waste heat from flue gas discharged by industrial equipment. Its essence is to transfer waste heat in flue gas to a cold medium (such as water, air, heat transfer oil, etc.) through "heat transfer", realize waste heat reuse (such as heating water supply, preheating combustion-supporting air, generating steam, etc.), and ultimately achieve the purpose of improving energy utilization efficiency, reducing flue gas temperature, and reducing pollutant emissions. It is one of the key devices for industrial energy saving and green production.

[0003] A spiral finned tube heat exchanger is a relatively common type of heat exchanger. Its core feature is that spiral fins are wound, welded or rolled on the outer surface of the base pipe (usually a circular pipe) of the heat exchanger. By increasing the heat transfer area and strengthening the fluid disturbance, the heat transfer efficiency is improved. Multiple spiral finned heat exchange tubes are arranged in combination and staggered. Cold water that needs to be heat exchanged flows from the spiral finned heat exchange tube. High-temperature flue gas is made to flow through multiple groups of spiral finned heat exchange tubes by the action of a fan, and the heat in the flue gas is then transferred to the cold water, causing the cold water to warm up.

[0004] In actual application, multiple groups of spiral finned heat exchange tubes are usually arranged horizontally. The flue gas contains a lot of dust. Even if the flue gas is preliminarily screened and filtered, it will still contain fine dust. When the flue gas contacts the heat exchange tube for heat exchange, the dust in the flue gas will accumulate in the gaps between the spiral fins. Especially, the dust will accumulate in the fin gaps above the spiral finned heat exchange tube (for the fin gaps below, due to the gravity of the dust, it is easy to naturally fall to the fin gaps above the group of spiral finned heat exchange tubes below). The high impedance of the dust accumulated on the surface of the heat exchange tube will greatly weaken the heat transfer efficiency. Therefore, regular cleaning of dust is the core to ensure the working efficiency of the heat exchanger. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a spiral finned tube heat exchanger to solve the technical problems mentioned in the background.

[0006] To achieve the above object, the present application provides the following technical scheme: A spiral finned tube heat exchanger, comprising a box, the inside of the box is provided with a heat exchanger assembly, the heat exchanger assembly comprises a plurality of groups of staggered heat exchange tubes, the heat exchange tube comprises a base pipe, one end of the base pipe is provided with a water inlet, the other end is provided with a water outlet, the outside of the base pipe is provided with an outer spiral fin, the inside of the base pipe is provided with a spiral fitting groove matched with the outer spiral fin, the end of the base pipe is threadedly connected with a plug cover, the side of the plug cover is connected with an inner spiral fin, the inner edge of the inner spiral fin is tooth-shaped, the inner spiral fin and the spiral fitting groove are fitted and installed, in the heat exchanger assembly, the water inlets of the two adjacent groups of heat exchange tubes are connected with each other, and the water outlets of the two adjacent groups of heat exchange tubes are connected with each other through the setting of a bend pipe, the water inlet of one group of heat exchange tubes of the heat exchanger assembly is connected with a water inlet main pipe, the water inlet main pipe is connected with a water supply device, and the water outlet of one group of heat exchange tubes of the heat exchanger assembly is connected with a water outlet main pipe, the water outlet main pipe is connected with a water tank, and the water tank is connected with a water using device, the top of the plurality of groups of heat exchange tubes of the heat exchanger assembly is provided with a dust removal assembly, and the dust removal assembly is driven by the water flow in the water tank.

[0007] By adopting the above technical scheme, the inner spiral fin is movably installed by setting the spiral fitting groove on the inside of the base pipe, the spiral distribution trajectories of the spiral fitting groove and the outer spiral fin are the same, and then the spiral distribution trajectories of the outer spiral fin and the inner spiral fin are also the same, so the fin root of the outer spiral fin and the outer edge of the inner spiral fin have the shortest distance on the heat transfer path, when the high-temperature flue gas transfers heat to the outer spiral fin, the heat can be transferred to the inner spiral fin through the shortest heat transfer path, the contact area of the inner spiral fin with the cold medium is larger, so that the heat transfer efficiency between the flue gas and the cold medium can be improved, the inside of the inner spiral fin is tooth-shaped, the tooth-shaped structure can disturb the flow of the cold medium, so that more vortexes are generated, so that the cold medium can better exchange heat with the inner wall of the base pipe and the inner spiral fin.

[0008] The present application further provides that the water tank comprises a shell, the inside of the shell is formed into an S-shaped water channel through the setting of a plurality of baffles, and the bottom of the shell is provided with a drain pipe, the drain pipe is connected with the water using device.

[0009] As preferred, the S-shaped water channel with a larger space makes the water level entering the water tank lower, that is, the water level entering the water tank only covers the lower half of the driving impeller, the driving impeller is driven to rotate by the water flowing in the S-shaped water channel, so as to drive a plurality of dust removal assemblies to rotate, and the accumulation of dust on the top of the heat exchange tube is reduced.

[0010] The present application further provides that one end of the S-shaped water channel is communicated with the water outlet main pipe, the other end is communicated with the drain pipe, and the diameter of the S-shaped water channel is greater than that of the water outlet main pipe.

[0011] Preferably, the S-shaped water channel is arranged so that water entering the water tank can flow in an S-shaped path to act on each set of driving impellers to drive the plurality of dust removal assemblies to rotate.

[0012] The dust removal assembly comprises a transmission rod, which is rotatably connected to the outer wall of the tank body and extends into the interior of the shell, and a plurality of dust removal runners are arranged on the outer portion of the transmission rod, the plurality of dust removal runners are distributed in the gaps between the outer spiral fins, and one end of the transmission rod located in the interior of the shell is provided with a driving impeller.

[0013] Preferably, the dust removal assembly is arranged above the heat exchange pipe, and the dynamic dust removal assembly can reduce the accumulation of dust in the gaps between the outer spiral fins.

[0014] The top of the outer spiral fin is provided with an open slot for embedding the transmission rod.

[0015] Preferably, the open slot is arranged at the top of the outer spiral fin for installing the transmission rod, so that the transmission rod can be closer to the outer wall of the base pipe, and the dust removal runners on the outer portion of the transmission rod can also be closer to the outer wall of the base pipe, thereby achieving deep cleaning of the gaps between the outer spiral fins.

[0016] The heat exchanger assembly is provided with a plurality of groups, and the water inlets of the heat exchange pipes of one group of the plurality of groups of heat exchanger assemblies are in communication with the water inlet main pipe.

[0017] Preferably, the plurality of groups of heat exchanger assemblies are arranged in parallel for use, which can sufficiently exchange heat with high-temperature flue gas, thereby improving the working efficiency of the heat exchange equipment.

[0018] The water outlets of the heat exchange pipes of one group of the plurality of groups of heat exchanger assemblies are in communication with the water outlet main pipe.

[0019] Preferably, the plurality of groups of heat exchanger assemblies are connected to the same group of water inlet main pipe and water outlet main pipe, so that the water supply device can supply water to the plurality of groups of heat exchanger assemblies at the same time, and the water outlets of the plurality of groups of heat exchanger assemblies are connected to the water outlet main pipe to discharge water into the water tank.

[0020] The bottom of the tank body is provided with a dust removal hatch for periodically cleaning the dust accumulated in the tank body.

[0021] Preferably, the dust removal hatch is arranged at the bottom of the tank body for periodic cleaning and maintenance of the heat exchange equipment by the staff.

[0022] In summary, the present application mainly has the following beneficial effects:

[0023] The present application has the following beneficial effects: the inner spiral fin is movably installed in the inner side of the base pipe through the spiral fitting groove, the spiral distribution trajectories of the spiral fitting groove and the outer spiral fin are the same, and the spiral distribution trajectories of the outer spiral fin and the inner spiral fin are also the same, so that the fin root of the outer spiral fin and the outer edge of the inner spiral fin have the shortest distance on the heat transfer path, when the high-temperature flue gas transfers heat to the outer spiral fin, the heat can be transferred to the inner spiral fin through the shortest heat transfer path, the inner side of the inner spiral fin is in a tooth shape, the tooth structure can disturb the flow of the cold medium, so that more vortexes are generated, and the cold medium can better exchange heat with the inner wall of the base pipe and the inner spiral fin.

[0024] The present application has the following beneficial effects: the inner spiral fin is movably installed in the inner side of the base pipe through the spiral fitting groove, the spiral fitting groove and the outer spiral fin have the same spiral distribution trajectory, and the spiral fitting groove and the inner spiral fin also have the same spiral distribution trajectory, so that the fin root of the outer spiral fin and the outer edge of the inner spiral fin have the shortest distance on the heat transfer path, when the high-temperature flue gas transfers heat to the outer spiral fin, the heat can be transferred to the inner spiral fin through the shortest heat transfer path, the inner side of the inner spiral fin is in a tooth shape, the tooth structure can disturb the flow of the cold medium, so that more vortexes are generated, and the cold medium can better exchange heat with the inner wall of the base pipe and the inner spiral fin. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present application;

[0026] Figure 2 It is a schematic diagram of the heat exchanger assembly structure of the present application;

[0027] Figure 3 It is a schematic diagram of the heat exchanger tube structure of the present application;

[0028] Figure 4 It is a schematic diagram of the spiral fitting groove distribution of the present application;

[0029] Figure 5 It is a schematic diagram of the inner spiral fin structure of the present application;

[0030] Figure 6 It is a schematic diagram of the water inlet main pipe and the water outlet main pipe distribution of the present application;

[0031] Figure 7 It is a schematic diagram of the heat exchanger tube and the ash removal assembly distribution of the present application;

[0032] Figure 8The internal structure diagram of the water tank of the present application;

[0033] Figure 9 The distribution plan of the outer spiral fin, base pipe and inner spiral fin of the present application;

[0034] Figure 10 The distribution diagram of the outer spiral fin and inner spiral fin of the present application.

[0035] Explanation of reference signs:

[0036] 1, tank; 2, heat exchanger assembly; 3, heat exchange pipe; 301, base pipe; 302, water inlet; 303, water outlet; 304, outer spiral fin; 305, open slot; 306, spiral fitting groove; 307, plug cover; 308, inner spiral fin; 4, elbow; 5, water inlet main pipe; 6, water outlet main pipe; 7, water tank; 701, shell; 702, baffle; 703, S-shaped water channel; 704, drain pipe; 8, ash cleaning assembly; 801, transmission rod; 802, ash cleaning runner; 803, driving impeller. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0038] The embodiments of the present application will be described below according to the overall structure of the present application.

[0039] Please refer to Figures 1-10 A spiral fin tube heat exchanger, comprising a tank 1, the inside of the tank 1 is provided with a heat exchanger assembly 2, the heat exchanger assembly 2 comprises multiple groups of staggered distribution heat exchange pipes 3, the heat exchange pipe 3 comprises a base pipe 301, one end of the base pipe 301 is provided with a water inlet 302, the other end is provided with a water outlet 303, the outside of the base pipe 301 is provided with an outer spiral fin 304, the inside of the base pipe 301 is provided with a spiral fitting groove 306 matched with the outer spiral fin 304, the end of the base pipe 301 is threadedly connected with a plug cover 307, the side of the plug cover 307 is connected with an inner spiral fin 308, the inner edge of the inner spiral fin 308 is tooth-shaped, the inner spiral fin 308 is spiral-bent by a metal steel strip, and the metal steel strip is equally punched with multiple tooth grooves, the inner spiral fin 308 and the spiral fitting groove 306 are fitted and installed, and then the inner spiral fin 308 can be spirally disassembled from the inside of the base pipe 301, when the inside of the base pipe 301 accumulates the frozen scale, the disassembled inner spiral fin 308 can play a role in breaking the scale and taking out part of the scale;

[0040] In the heat exchanger assembly 2, the water inlets 302 of the adjacent two groups of heat exchange pipes 3 are connected to each other, the water inlets 302 are movable joints, and the water outlets 303 of the adjacent two groups of heat exchange pipes 3 are connected to each other through the setting of the bend pipe 4, the bend pipe 4 and the water outlet 303 are processed by welding process, the water inlet 302 of one group of heat exchange pipes 3 in the heat exchanger assembly 2 is connected with the water inlet main pipe 5, the water inlet main pipe 5 is connected with the water supply device, the water supply device includes water supply pipeline, water source, control system and water pump, and the water outlet 303 of one group of heat exchange pipes 3 in the heat exchanger assembly 2 is connected with the water outlet main pipe 6, the water outlet main pipe 6 is connected with the water tank 7, the water tank 7 is connected with the water using device, such as industrial water or factory dormitory washing water, the upper part of the plurality of groups of heat exchange pipes 3 of the heat exchanger assembly 2 is provided with the ash removal assembly 8, and the ash removal assembly 8 is driven by the water flow in the water tank 7.

[0041] In the above embodiment, please refer to Figure 8 , the water tank 7 includes a shell 701, the inside of the shell 701 is formed into an S-shaped water channel 703 by setting a plurality of baffles 702, and the bottom of the shell 701 is provided with a drain pipeline 704, the drain pipeline 704 is connected with the water using device, by setting the larger S-shaped water channel 703, the water liquid level entering the water tank 7 is lowered, that is, the water liquid level entering the water tank 7 only covers the lower half of the driving impeller 803, the driving impeller 803 is rotated by the water flowing in the S-shaped water channel 703, thereby driving the plurality of ash removal assemblies 8 to rotate, reducing the accumulation of dust on the top of the heat exchange pipe 3.

[0042] In the above embodiment, please refer to Figure 8 , one end of the S-shaped water channel 703 is communicated with the water outlet main pipe 6, the other end is communicated with the drain pipeline 704, and the diameter of the S-shaped water channel 703 is greater than that of the water outlet main pipe 6, by setting the S-shaped water channel 703, the water entering the water tank 7 can flow in an S-shaped route to act on each group of driving impellers 803, thereby driving the plurality of ash removal assemblies 8 to rotate.

[0043] In the above embodiment, please refer to Figure 7 , the ash removal assembly 8 includes a transmission rod 801, the transmission rod 801 is rotatably connected with the outer wall of the tank 1, and the transmission rod 801 extends into the inside of the shell 701, a plurality of ash removal runners 802 are arranged on the outside of the transmission rod 801, the plurality of ash removal runners 802 are distributed in the gap of the outer spiral fin 304, and one end of the transmission rod 801 located in the inside of the shell 701 is provided with the driving impeller 803, by setting the ash removal assembly 8 above the heat exchange pipe 3, the dynamic ash removal assembly 8 can be rotated to reduce the accumulation of dust in the gap of the outer spiral fin 304.

[0044] In the above embodiment, please refer to Figure 3 and Figure 7The top of the outer spiral fin 304 is provided with an open slot 305 for embedding the transmission rod 801, and the open slot 305 is used for installing the transmission rod 801, so that the transmission rod 801 can be closer to the outer wall of the base pipe 301, and the dust removal rotating wheel 802 outside the transmission rod 801 can also be closer to the outer wall of the base pipe 301, so as to realize deep dust removal of the gap between the outer spiral fin 304, the outer spiral fin 304 is made of metal steel belt spirally wound on the outer wall of the base pipe 301, and is made by high-frequency welding, and the metal steel belt is punched with a plurality of open slots 305 at equal intervals, so that when the metal steel belt is spirally welded on the outside of the base pipe 301, the plurality of open slots 305 are distributed along the same axis.

[0045] In the above embodiment, please refer to Figure 6 The heat exchanger assembly 2 is provided with a plurality of groups, and the water inlets 302 of the heat exchange pipes 3 of one group of the plurality of groups of heat exchanger assemblies 2 are in communication with the water inlet header 5, and the plurality of groups of heat exchanger assemblies 2 are used in parallel, which can sufficiently exchange heat with high-temperature flue gas, thereby improving the working efficiency of the heat exchange equipment.

[0046] In the above embodiment, please refer to Figure 6 The water outlets 303 of the heat exchange pipes 3 of one group of the plurality of groups of heat exchanger assemblies 2 are in communication with the water outlet header 6, and the plurality of groups of heat exchanger assemblies 2 are connected with the same group of water inlet header 5 and water outlet header 6, so that the water supply device can supply water to the plurality of groups of heat exchanger assemblies 2 at the same time, and the water outlets of the plurality of groups of heat exchanger assemblies 2 are concentrated and discharged into the water tank 7 through the water outlet header 6.

[0047] In the above embodiment, please refer to Figure 1 The bottom of the box body 1 is provided with a dust removal hatch for periodically cleaning the dust accumulated in the box body 1, and the dust removal hatch is used for the staff to periodically clean and maintain the heat exchange equipment.

[0048] In the specific work, the high-temperature flue gas enters the inside of the box body 1 from the smoke exhaust pipe under the action of the fan, the water supply device pushes the water from the water inlet header 5 into the inside of each group of heat exchanger assemblies 2, the cold water enters one group of heat exchange pipes 3 of the heat exchanger assembly 2, and the cold water is continuously circulated in the plurality of heat exchange pipes 3 through the elbow pipe 4, and finally the cold water is discharged into the water tank 7 through the water outlet header 6.

[0049] When the high-temperature flue gas enters the inside of the box body 1, it exchanges heat with the multiple sets of heat exchange pipes 3, and the heat in the flue gas is transferred to the outer spiral fin 304 and the base pipe 301, the heat of the outer spiral fin 304 and the base pipe 301 is transferred to the cold water, and the heat of the outer spiral fin 304 is transferred to the inner spiral fin 308 in the shortest heat transfer path, the inner spiral fin 308 and the spiral embedded groove 306 are spirally embedded and installed, that is, the arrangement of the spiral embedded groove 306 can make the inner spiral fin 308 and the inner wall of the base pipe 301 better contact and fit, reduce the installation gap, the more the gap, the lower the heat conduction efficiency, and the medium flowing in the base pipe 301 can fill the installation gap, so that the outer spiral fin 304 and the base pipe 301 can more efficiently exchange heat with the inner spiral fin 308, the inner edge of the inner spiral fin 308 extends to the center of the cold water, and the inner edge of the inner spiral fin 308 is tooth-shaped to increase the vortex of the cold water, that is, the inner spiral fin 308 can better exchange heat with the cold water.

[0050] The cold water of the multiple sets of heat exchange pipes 3 after heat exchange is raised in temperature, and is uniformly discharged from the water outlet main pipe 6 into the water tank 7, and finally discharged from the water outlet pipeline 704 of the water tank 7 to the water using device. Since the S-shaped water channel 703 of the water tank 7 has a larger space, when the water enters the inside of the water tank 7, the liquid surface only covers the lower half of the driving impeller 803, so as to drive the driving impeller 803 to rotate by using water power, and the driving impeller 803 drives the transmission rod 801 connected thereto to rotate, and the transmission rod 801 drives multiple sets of driving impellers 803 to rotate. When the multiple sets of heat exchange pipes 3 exchange heat with the high-temperature flue gas, the dust in the flue gas will accumulate in the gap between the upper fins of the heat exchange pipes 3, that is, the dust is easy to accumulate at the position of the multiple sets of driving impellers 803, and the dynamic driving impeller 803 can reduce the accumulation of dust by rotating, and the dynamic driving impeller 803 can increase the vortex of the flue gas, so that the flue gas can better exchange heat with the heat exchange pipes 3. The dust cleaned by the dust cleaning assembly 8 during the daily work of the heat exchange equipment is accumulated at the inner bottom of the box body 1, and the staff can periodically clean it by opening the dust compartment door at the bottom of the box body 1.

[0051] When the staff needs to clean the scale of the heat exchange pipes 3, the heat exchange equipment needs to be temporarily closed, and the valve of the water outlet main pipe 6 is closed. Since the multiple sets of heat exchange pipes 3 of the heat exchanger assembly 2 are welded together by multiple sets of elbow pipes 4, the plug cover 307 of the heat exchange pipe 3 is opened, and the inner spiral fin 308 connected with the plug cover 307 is rotated out from the inside of the base pipe 301. When the inner spiral fin 308 rotates out from the inside of the base pipe 301, it can scrape and break the solidified scale, and then the water from the water inlet main pipe 5 is used to flush the inside of the base pipe 301 of each set of heat exchange pipe 3.

[0052] Although the embodiments of the present application have been shown and described, the specific embodiments are merely exemplary and are not to be construed as limiting the present application, and the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner, and those skilled in the art can make modifications, replacements and variations to the embodiments without creative contribution after reading the specification, and as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A helical finned tube heat exchanger comprising a casing (1), characterised in that: The interior of the box (1) is provided with a heat exchanger assembly (2), the heat exchanger assembly (2) comprises a plurality of groups of staggered heat exchange pipes (3), the heat exchange pipe (3) comprises a base pipe (301), one end of the base pipe (301) is provided with a water inlet (302), the other end is provided with a water outlet (303), the outside of the base pipe (301) is provided with an outer spiral fin (304), the inside of the base pipe (301) is provided with a spiral fitting groove (306) matched with the outer spiral fin (304), the end of the base pipe (301) is threadedly connected with a plug cover (307), the side of the plug cover (307) is connected with an inner spiral fin (308), the inner edge of the inner spiral fin (308) is tooth-shaped, the inner spiral fin (308) and the spiral fitting groove (306) are fitted and installed, in the heat exchanger assembly (2), the water inlets (302) of the adjacent two groups of heat exchange pipes (3) are connected with each other, and the water outlets (303) of the adjacent two groups of heat exchange pipes (3) are connected with each other through the setting of the elbow pipe (4), the water inlet (302) of one group of heat exchange pipes (3) in the heat exchanger assembly (2) is connected with a water inlet main pipe (5), the water inlet main pipe (5) is connected with a water supply device, and the water outlet (303) of one group of heat exchange pipes (3) in the heat exchanger assembly (2) is connected with a water outlet main pipe (6), the water outlet main pipe (6) is connected with a water tank (7), the water tank (7) is connected with a water using device, the water tank (7) comprises a shell (701), the upper part of the plurality of groups of heat exchange pipes (3) of the heat exchanger assembly (2) is provided with a dust cleaning assembly (8), the dust cleaning assembly (8) is driven by the water flow in the water tank (7), the dust cleaning assembly (8) comprises a transmission rod (801), the transmission rod (801) is rotatably connected with the outer wall of the box (1), and the transmission rod (801) extends into the inside of the shell (701), the outside of the transmission rod (801) is provided with a plurality of dust cleaning rotating wheels (802), the plurality of dust cleaning rotating wheels (802) are distributed in the gap of the outer spiral fin (304), and one end of the transmission rod (801) located in the inside of the shell (701) is provided with a driving impeller (803), the top of the outer spiral fin (304) is provided with an open slot (305), and the open slot (305) is used for fitting the transmission rod (801).

2. The helical finned tube heat exchanger according to claim 1, wherein: The inside of the shell (701) is formed into an S-shaped water channel (703) through the setting of a plurality of baffles (702), and the bottom of the shell (701) is provided with a drainage pipeline (704), the drainage pipeline (704) is connected with the water using device.

3. A helical finned tube heat exchanger according to claim 2, wherein: One end of the S-shaped water channel (703) is communicated with the water outlet main pipe (6), the other end is communicated with the drainage pipeline (704), and the diameter of the S-shaped water channel (703) is greater than that of the water outlet main pipe (6).

4. A helical finned tube heat exchanger according to claim 3, wherein: The heat exchanger assembly (2) is provided with a plurality of groups, the water inlets (302) of one group of heat exchange pipes (3) in the plurality of groups of heat exchanger assemblies (2) are communicated with the water inlet main pipe (5).

5. A helical finned tube heat exchanger according to claim 4, wherein: The water outlets (303) of one group of heat exchange pipes (3) in the plurality of groups of heat exchanger assemblies (2) are communicated with the water outlet main pipe (6).

6. A helical finned tube heat exchanger according to claim 5 wherein: The bottom of the box (1) is provided with a dust cleaning hatch for periodically cleaning the dust accumulated in the box (1).

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