Condensation type heat exchanger

Abstract

The utility model provides a condensation type heat exchanger which comprises a shell, an inner cavity is formed in the shell, an air inlet and an air outlet which are used for flue gas to enter and exit the inner cavity are formed in the shell, inner supporting frames are arranged in the inner cavity in the circumferential direction, at least part of corrugated pipes penetrate into the shell and are spirally wound on the peripheries of the inner supporting frames, and the corrugated pipes are connected with the inner supporting frames. The corrugated pipe serves as a liquid channel, protrusions and grooves of the pipe wall of the corrugated pipe form corrugated gaps allowing flue gas to pass through, the corrugated pipe divides the inner cavity into an inner layer cavity and an outer layer cavity, a partition plate clamped and fixed in the inner supporting frame is arranged in the inner layer cavity, and the outer layer cavity is provided with a partition plate clamped and fixed in the outer supporting frame. The partition plate divides the inner-layer cavity into an air inlet cavity connected with the air inlet and an air outlet cavity connected with the air outlet, smoke sequentially passes through the air inlet cavity, the outer-layer cavity and the air outlet cavity to exchange heat with water flow in the corrugated pipe, high-temperature smoke exchanges heat with liquid in the corrugated pipe twice, waste heat of the smoke is fully utilized, and heat exchange efficiency is improved. And the contact area between flue gas and the pipe wall is greatly increased, and the heat exchange efficiency is remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of heat exchanger technology, and in particular to a condensing heat exchanger. Background Technology

[0002] Heating systems need to be equipped with heat exchangers, where the high-temperature flue gas generated by fuel combustion comes into contact with the low-temperature liquid for heat exchange, and heating is achieved by rapidly heating the low-temperature liquid.

[0003] Currently, common heat exchangers typically use round or flat tubes as condenser tubes. The contact area between high-temperature flue gas and liquid is small, and the high-temperature flue gas and condenser tube usually only exchange heat once. After entering the inner cavity and making one contact with the condenser tube, the high-temperature flue gas is directly discharged from the air outlet, which cannot fully utilize the heat energy of the high-temperature flue gas, resulting in low heat exchange efficiency.

[0004] CN117730232A discloses a condensing heat exchanger. This condensing heat exchanger uses rigid condensing tubes and installs a disc-shaped guide vane made of insulating material inside the condensing tubes. The disc-shaped guide vane allows high-temperature flue gas to pass through the condensing tubes twice, which can effectively improve the heat exchange efficiency. However, in order to maintain a certain gap between each layer of condensing tubes and fix the disc-shaped guide vane as a heat insulation plate, multiple boss structures are set on the pipe wall, resulting in a complex pipe structure and high production cost. In addition, the disc-shaped guide vane completely blocks the combustion chamber and condensing chamber, preventing hot gas from passing between the two. This places high requirements on the product precision and assembly precision of the disc-shaped guide vane. Utility Model Content

[0005] To address the problems of complex structure and high production cost associated with existing condensing heat exchangers that use pipes to fix insulation plates, this invention provides a condensing heat exchanger, including a shell with an inner cavity. The shell has an inlet and an outlet for flue gas to enter and exit the inner cavity. An inner support frame is arranged circumferentially within the inner cavity. At least a portion of a corrugated pipe penetrates the shell and is spirally wound around the outer periphery of the inner support frame. The corrugated pipe serves as a liquid channel, with protrusions and grooves on the pipe wall forming corrugated gaps to allow flue gas to pass through. The corrugated pipe divides the inner cavity into an inner chamber and an outer chamber. A partition, clamped and fixed within the inner support frame, is provided in the inner chamber, further dividing it into an inlet chamber connected to the inlet and an outlet chamber connected to the outlet. The flue gas sequentially exchanges heat with the water flow within the corrugated pipe through the inlet chamber, the outer chamber, and the outlet chamber.

[0006] Specifically, the partition includes an mounting plate and a heat insulation plate disposed on the mounting plate. The heat insulation plate is refractory cement that has been cast and cured in the cavity formed by the mounting plate and the corrugated pipe.

[0007] Specifically, bolt heads are provided on both sides of the mounting plate, and the inner support frame includes a first threaded bushing and a second threaded bushing. One end of the first threaded bushing is threadedly connected to the mounting plate, and the other end of the first threaded bushing is threadedly connected to the upper end cover through a fastener. One end of the second threaded bushing is threadedly connected to the mounting plate, and the other end of the second threaded bushing is threadedly connected to the lower end cover through a fastener.

[0008] Specifically, the sidewalls of the first and second threaded bushings are internally tangent to the sidewall of the mounting plate.

[0009] Specifically, an outer support frame is provided on the outer periphery of the inner support frame, and the upper and lower ends of the corrugated pipe are double-wound, with the outer support frame clamping the double-wound corrugated pipe.

[0010] Specifically, the outer support frame is a third threaded bushing arranged circumferentially between the upper end cover and the lower end cover.

[0011] Specifically, an upper insulation plate and a lower insulation plate are respectively installed on the outer sides of the upper and lower end covers.

[0012] Specifically, the cylinder wall is a square steel sheet bent into a cylindrical shape. The length of the cylinder wall is greater than the circumference of the end cap. The cylinder wall surrounds the outer perimeter of the outer support frame, and a hose clamp is fitted around the outer perimeter of the cylinder wall.

[0013] Specifically, high-temperature resistant sealing strips are installed at the upper and lower ends of the cylinder wall, respectively. The sealing strip has a U-shaped mounting part and a hollow tube set at the upper end of the sealing strip. The mounting part is sleeved on the upper and lower ends of the cylinder wall, and the inner side of the mounting part is attached to the side wall of the upper end cover and the lower end cover. The upper insulation plate and the lower insulation plate press the hollow tube tightly.

[0014] Specifically, the corrugated pipe has a liquid inlet at the end near the air outlet and a liquid outlet at the end near the air inlet.

[0015] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0016] 1. This utility model provides a condensing heat exchanger. An inner support frame is designed in the inner cavity of the heat exchanger, and a corrugated tube is wound around the outer periphery of the inner support frame. A baffle is designed in the support frame, which forces the high-temperature flue gas to flow back through the corrugated gaps of the corrugated tube, sequentially through the air inlet chamber, the outer chamber, and the air outlet chamber, and to exchange heat with the liquid in the corrugated tube twice. This fully utilizes the waste heat of the flue gas, greatly increases the contact area between the flue gas and the tube wall, and significantly improves the heat exchange efficiency.

[0017] 2. In this invention, refractory cement is poured into the cavity formed by the mounting plate and the corrugated pipe, and then cured to form a heat insulation board. The cured refractory cement is embedded in the corrugated pipe, and the heat insulation board blocks the gap between the mounting plate and the corrugated pipe, which can completely block the air inlet chamber and the air outlet chamber, and has better sealing performance between the air inlet chamber and the air outlet chamber. In addition, the refractory cement further strengthens the flexible corrugated pipe and prevents the corrugated pipe from loosening.

[0018] 3. The corrugated pipe of this utility model adopts a double-layer winding method at both the upper and lower ends to fill and seal the gap between the corrugated pipe and the upper and lower end caps, so as to prevent the high-temperature flue gas from short-circuiting through the gap. The high-temperature flue gas can only flow between the inner and outer chambers through the corrugated gap, thus ensuring the heat exchange efficiency between the high-temperature flue gas and the liquid.

[0019] 4. This utility model uses a flexible corrugated tube wound in the inner support frame as a condenser tube, and refractory cement is poured into the corrugated tube to form a baffle. Compared with the prior art, the heat exchanger has a simple structure and can be quickly assembled by one person, reducing production time and production costs. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0021] Figure 2 This is a cross-sectional view of the present invention;

[0022] Figure 3 This is a schematic diagram of the high-temperature flue gas flow state of this utility model;

[0023] Figure 4 This is a schematic diagram of the support frame structure of this utility model;

[0024] Figure 5 This is a schematic diagram of the double-layer winding of the corrugated pipe of this utility model;

[0025] Figure 6 This is a schematic diagram of the mounting plate structure of this utility model;

[0026] Figure 7 This is a schematic diagram of the utility model in use.

[0027] Reference numerals: 1. Shell; 11. Upper end cover; 111. Air inlet; 12. Lower end cover; 121. Air outlet; 13. Cylinder wall; 14. Outer chamber; 15. Air inlet chamber; 16. Air outlet chamber; 17. Upper insulation plate; 18. Lower insulation plate; 19. Drain pipe; 2. Corrugated pipe; 21. Liquid inlet; 22. Liquid outlet; 3. Inner support frame; 31. First threaded bushing; 32. Second threaded bushing; 4. Partition plate; 41. Mounting plate; 42. Heat insulation plate; 43. Bolt head; 5. Outer support frame; 51. Third threaded bushing; 6. Hose clamp; 71. Flat head bolt; 72. Screw; 73. Nut; 8. Burner; 9. Air outlet pipe. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model. The specific implementation of the present utility model will be described in detail below with reference to specific embodiments.

[0029] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0030] like Figures 1-7 As shown, this utility model provides a condensing heat exchanger, including a shell 1, an inner cavity provided inside the shell 1, an inlet 111 and an outlet 121 for flue gas to enter and exit the inner cavity, an inner support frame 3 arranged circumferentially in the inner cavity, at least part of a corrugated pipe 2 passing through the shell 1 and spirally wound around the outer periphery of the inner support frame 3, the corrugated pipe 2 serving as a liquid channel, the protrusions and grooves on the wall of the corrugated pipe 2 forming corrugated gaps for flue gas to pass through, the corrugated pipe 2 dividing the inner cavity into an inner chamber and an outer chamber 14, a partition 4 clamped and fixed in the inner support frame 3 in the inner chamber, the partition 4 dividing the inner chamber into an inlet chamber connected to the inlet and an outlet chamber connected to the outlet, the flue gas sequentially passing through the inlet chamber, the outer chamber and the outlet chamber to exchange heat with the water flow in the corrugated pipe.

[0031] Specifically, the shell 1 is formed by an upper end cover 11, a lower end cover 12, and a cylindrical wall 13, and is cylindrical in shape. An inner cavity is provided within the shell 1. The upper end cover 11 and the lower end cover 12 of the shell 1 are respectively provided with an air inlet 111 and an air outlet 121. The air inlet 111 is connected to the burner 8, and the air outlet 121 is connected to the exhaust pipe 9. The high-temperature flue gas generated by combustion in the burner 8 enters the inner cavity through the air inlet 111, and exits through the air outlet 121 after moving through the inner cavity. In some embodiments, the air outlet 121 is connected to the air inlet of a fan, and the fan accelerates the flow rate of the flue gas in the heat exchanger.

[0032] An inner support frame 3 is provided in the inner cavity. The inner support frame 3 is arranged circumferentially and has through holes in the cylinder wall 13. At least part of the corrugated pipe 2 passes through the through holes into the shell 1 and is tightly wound in a spiral shape around the outer periphery of the inner support frame 3, dividing the inner cavity into an inner chamber and an outer chamber 14. The corrugated pipe 2 is a flexible pipe with a corrugated pleated structure. The pipe wall of the corrugated pipe 2 has alternating protrusions and grooves. Multiple layers of corrugated pipe 2 are wound in a spiral shape. The protrusions and grooves between adjacent layers of corrugated pipe 2 form corrugated gaps that allow high-temperature flue gas to pass through. The high-temperature flue gas flows between the inner chamber and the outer chamber 14 through the corrugated gaps.

[0033] The corrugated pipe 2 serves as a condenser tube, through which liquid flows. It is made of a material with good thermal conductivity, preferably stainless steel. The liquid to be heated, such as water, circulates within the corrugated pipe 2 after being pressurized by a water pump. An inlet 21 is located at the end of the corrugated pipe 2 near the outlet 121, and an outlet 22 is located at the end near the inlet 111. The liquid to be heated enters the heat exchanger through the inlet 21, exchanges heat with the high-temperature flue gas, and then flows out through the outlet 22. The low-temperature liquid and the high-temperature flue gas flow in opposite directions, increasing the average temperature difference between the two and improving the heat exchange efficiency. Because the wall of the corrugated pipe 2 has a corrugated pleated structure, the contact area between the liquid and the high-temperature flue gas increases when the high-temperature flue gas flows through the gaps in the corrugations, thereby improving the heat exchange efficiency.

[0034] The heat insulation plate 42 is clamped and fixed in the inner support frame 3. As a preferred embodiment of this utility model, the inner support frame 3 consists of six circumferentially installed first threaded bushings 31 and second threaded bushings 32 between the upper end cover 11 and the lower end cover 12. At least both ends of the threaded bushings are provided with internal threads. The threaded bushings can also be hollow cylindrical structures with internal threads inside. The first threaded bushings 31 and the second threaded bushings 32 are correspondingly arranged and are in the shape of regular hexagons. A partition 4 is provided between the first threaded bushings 31 and the second threaded bushings 32. The partition 4 includes a mounting plate 41 and a heat insulation plate 42. Bolt heads 43 are provided on both sides of the mounting plate 41. One end of the first threaded bushing 31 and the second threaded bushing 32 are respectively threaded to the upper and lower sides of the mounting plate 41. The other end of the first threaded bushing 31 is fixedly connected to the upper end cover 11 by a flat-head bolt 71. The other end of the second threaded bushing 32 is connected to the lower end cover 12 by a screw 72 and a nut 73 or a flat-head bolt 71. The bolt head 43 is located at the edge of the mounting plate 41, and the sidewalls of the first threaded bushing 31 and the second threaded bushing 32 are internally tangent to the sidewall of the mounting plate 41 to reduce the gaps generated when the bellows 2 is wound.

[0035] The baffle 4 is located in the inner chamber, dividing the inner chamber into an inlet chamber 15 connected to the inlet 111 and an outlet chamber 16 connected to the outlet 121. The baffle 4 blocks the path of high-temperature flue gas directly from the inlet 111 through the inner chamber to the outlet 121, forcing the high-temperature flue gas to flow through the inlet chamber 15, the outer chamber 14 and the outlet chamber 16 in sequence, turning back between the inner chamber and the outer chamber 14, prolonging the heat exchange path and heat exchange time, so that the high-temperature flue gas can fully exchange heat with the liquid in the bellows 2. The high-temperature flue gas entering the chamber needs to pass through the inlet chamber 15, the outer chamber 14 and the outlet chamber 16 in sequence and then be discharged from the outlet 121. When the high-temperature flue gas moves between the inner chamber and the outer chamber 14, the liquid in the bellows 2 undergoes two heat exchanges. Moreover, due to the small gap between the bellows, the high-temperature flue gas can fully contact the bellows 2, which significantly improves the heat exchange efficiency of the high-temperature flue gas.

[0036] The heat insulation plate 42 is located on the side of the mounting plate 41 near the air inlet 111. It is made of heat insulation material and is used to prevent the heat of the high-temperature flue gas in the air inlet chamber 15 from being directly transferred to the air outlet chamber 16 through the mounting plate 41, thus preventing heat loss. The mounting plate 41 serves as the base plate, and the corrugated pipe 2 serves as the side wall, forming a chamber with an open top. The heat insulation plate 42 is formed by pouring refractory cement into the chamber. The refractory cement is a high-viscosity slurry in its unhardened state. The refractory cement contains aggregates, refractory sand, and other solid particles, as well as explosion-proof fibers. The pore size of the corrugated gaps is approximately 1mm-3mm. The small pore size, based on the high viscosity and surface tension of the refractory cement, can prevent the refractory cement from leaking from the corrugated gaps, and the explosion-proof fibers can further increase the flow resistance of the cement slurry in the corrugated gaps. Refractory cement is cast and molded within the cavity, and after hardening, it is embedded in the corrugated pipe 2 to form a robust insulation layer, effectively preventing heat transfer. Simultaneously, the insulation plate blocks the gap between the mounting plate 41 and the corrugated pipe 2, completely isolating the inlet chamber 15 and the outlet chamber 16, ensuring that the high-temperature flue gas follows the required heat exchange path within the inner cavity, sequentially passing through the inlet chamber 15, the outer chamber 14, and the outlet chamber 16. Furthermore, the refractory cement embedded in the corrugated pipe 2 further secures it from the middle, preventing it from loosening under the impact of liquid flow.

[0037] An outer support frame 5 is also provided around the inner support frame 3. The outer support frame 5 consists of six circumferentially mounted third threaded bushings 51 between the upper end cover 11 and the lower end cover 12. The third threaded bushings 51 are arranged in a regular hexagonal pattern, and both ends of the third threaded bushings 51 are fixedly connected to the upper end cover 11 and the lower end cover 12 by screws 72 and nuts 73. Since the bellows 2 is spirally wound around the outer periphery of the inner support frame 3, there is a large gap between the bellows 2 and the upper end cover 11 and the lower end cover 12. Due to the low pressure at the gap, the flue gas can easily move between the inner chamber and the outer chamber 14 through the gap, and cannot fully exchange heat with the liquid in the bellows 2. Therefore, the bellows 2 adopts a double-layer winding method at both the upper and lower ends to fill and seal the end gaps, preventing the high-temperature flue gas from short-circuiting through the gaps. The third threaded bushing 51 contacts the pipe wall of the second layer of corrugated pipe 2 at both the upper and lower ends, clamping the double-wound corrugated pipe 2 and fixing both ends of the corrugated pipe 2.

[0038] Upper insulation plate 17 and lower insulation plate 18 are respectively installed on the outer side of upper end cover 11 and lower end cover 12. Upper insulation plate 17 and lower insulation plate 18 can be made of high temperature resistant insulation materials such as rock wool. Upper insulation plate 17 and lower insulation plate 18 are fixedly connected to the outer side of end cover by flat head bolts 71 or screws 72 and nuts 73. The diameter of upper insulation plate 17 and lower insulation plate 18 is slightly larger than the diameter of upper end cover 11 and lower end cover 12. Upper insulation plate 17 and lower insulation plate 18 provide insulation for upper end cover 11 and lower end cover 12, reducing heat loss to the outside.

[0039] The cylinder wall 13 is a square steel sheet bent into a cylindrical shape. The length of the cylinder wall 13 is greater than the circumference of the end cap, and the width of the cylinder wall 13 matches the width of the third threaded bushing 51. The cylinder wall 13 surrounds the outer periphery of the outer support frame 5, with partial overlap. A hose clamp 6 is fitted around the outer periphery of the cylinder wall 13. Preferably, there are two hose clamps 6, fitted on the upper and lower sides of the cylinder wall 13 respectively, and the cylinder wall 13 is locked using the hose clamps 6. This cylinder wall 13 facilitates the installation of the bellows 2. When installing the bellows 2, the inlet 21 and outlet 22 are passed through the through hole, and high-temperature resistant sealant is applied to the through hole to fix the bellows 2 and prevent high-temperature flue gas leakage. Finally, the cylinder wall 13 is locked using the hose clamps 6.

[0040] The upper and lower ends of the cylinder wall 13 contact the upper end cover 11 and the lower end cover 12, respectively. To ensure the sealing performance of the contact surfaces between the cylinder wall 13 and the upper and lower end covers 11 and 12, high-temperature resistant sealing strips are installed at the upper and lower ends of the cylinder wall 13. The sealing strip has a U-shaped mounting portion and a hollow tube at one end away from the opening of the mounting portion. The mounting portion is fitted onto the upper and lower ends of the cylinder wall 13, and the inner side of the mounting portion is attached to the sidewalls of the upper and lower end covers 11 and 12. The upper insulation plate 17 and the lower insulation plate 18 press the hollow tube tightly, and the sealing strip is pressed tightly on both sides, thereby preventing leakage between the cylinder wall 13 and the end covers. An insulation layer is also provided on the outer periphery of the cylinder wall 13. The insulation layer can be fixed to the surface of the shell 1 by adhesive or binding, providing insulation for the cylinder wall 13 while further improving the sealing performance of the overlapping parts of the cylinder wall 13.

[0041] A drain pipe 19 is also provided in the cylinder wall 13. When the heat exchanger is installed, the drain pipe 19 is located at the bottom of the cylinder wall 13, and the condensate on the surface of the corrugated pipe 2 drips down through the drain pipe 19.

[0042] In use, the burner 8 is installed at the air inlet 111 and is fixedly connected to the heat exchanger using the screw 72 and nut 73 at the end of the outer support frame 5. The air outlet 121 is installed at the air outlet and is fixedly connected to the heat exchanger using the screw 72 and nut 73 at the end of the inner support frame 3. The liquid inlet 21 and liquid outlet 22 of the corrugated pipe 2 are respectively connected to the circulation pipeline. The high-temperature flue gas and the liquid in the corrugated pipe 2 exchange heat fully, and the temperature of the liquid in the circulation pipeline is rapidly heated.

[0043] The assembly process of the condensing heat exchanger is as follows: First, assemble the overall frame, connect the inner support frame 3 to the upper end cover 11 and the lower end cover 12, then wind the bellows 2 around the side wall of the inner support frame 3, with the upper and lower ends of the bellows 2 being double-wound, and tighten the bellows 2, then install the third threaded bushing 51 to clamp the bellows 2, then pour refractory cement on the mounting plate 41, and after the refractory cement has cured, surround the cylinder wall 13 around the third threaded bushing 51, use the hose clamp 6 to lock the cylinder wall 13, and apply sealant to the protruding part of the bellows 2 to complete the assembly of the condensing heat exchanger.

[0044] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A condensing heat exchanger, characterized in that, The system includes a housing (1) with an inner cavity. The housing (1) has an inlet (111) and an outlet (121) for flue gas to enter and exit the inner cavity. An inner support frame (3) is arranged circumferentially within the inner cavity. At least a portion of a corrugated pipe (2) penetrates the housing (1) and spirally winds around the outer periphery of the inner support frame (3). The corrugated pipe (2) serves as a liquid channel. The protrusions and grooves on the wall of the corrugated pipe (2) form corrugated gaps that allow flue gas to pass through. The tube (2) divides the inner cavity into an inner chamber and an outer chamber (14). The inner chamber is provided with a partition (4) clamped and fixed in the inner support frame (3). The partition (4) divides the inner chamber into an air inlet chamber (15) connected to the air inlet (111) and an air outlet chamber (16) connected to the air outlet (121). The flue gas exchanges heat with the water flow in the corrugated tube (2) in sequence through the air inlet chamber (15), the outer chamber (14) and the air outlet chamber (16).

2. The condensing heat exchanger according to claim 1, characterized in that, The partition (4) includes an mounting plate (41) and a heat insulation plate (42) disposed on the mounting plate (41). The heat insulation plate (42) is refractory cement that is cast into the cavity formed by the mounting plate (41) and the corrugated pipe (2) and cured.

3. The condensing heat exchanger according to claim 2, characterized in that, The housing (1) is formed by an upper end cover (11), a lower end cover (12) and a cylindrical wall (13). Bolt heads (43) are provided on both sides of the mounting plate (41). The inner support frame (3) includes a first threaded bushing (31) and a second threaded bushing (32). One end of the first threaded bushing (31) is threaded to the mounting plate (41), and the other end of the first threaded bushing (31) is threaded to the upper end cover (11) by fasteners. One end of the second threaded bushing (32) is threaded to the mounting plate (41), and the other end of the second threaded bushing (32) is threaded to the lower end cover (12) by fasteners.

4. The condensing heat exchanger according to claim 3, characterized in that, The sidewalls of the first threaded bushing (31) and the second threaded bushing (32) are internally tangent to the sidewall of the mounting plate (41).

5. The condensing heat exchanger according to claim 3, characterized in that, An outer support frame (5) is provided on the outer periphery of the inner support frame (3). The upper and lower ends of the corrugated pipe (2) are double-wound, and the outer support frame (5) clamps the double-wound corrugated pipe (2).

6. The condensing heat exchanger according to claim 5, characterized in that, The outer support frame (5) is a third threaded bushing (51) arranged circumferentially between the upper end cover (11) and the lower end cover (12).

7. The condensing heat exchanger according to claim 6, characterized in that, The upper end cover (11) and the lower end cover (12) are respectively equipped with an upper insulation plate (17) and a lower insulation plate (18).

8. The condensing heat exchanger according to claim 7, characterized in that, The cylindrical wall (13) is a square steel sheet bent into a cylindrical shape. The length of the cylindrical wall (13) is greater than the circumference of the end cap. The cylindrical wall (13) surrounds the outer perimeter of the outer support frame (5). A hose clamp (6) is fitted around the outer perimeter of the cylindrical wall (13).

9. The condensing heat exchanger according to claim 8, characterized in that, High-temperature resistant sealing strips are installed at the upper and lower ends of the cylinder wall (13), respectively. The sealing strip has a U-shaped mounting part and a hollow tube set at the upper end of the sealing strip. The mounting part is sleeved on the upper and lower ends of the cylinder wall (13). The inner side of the mounting part is attached to the side wall of the upper end cover (11) and the lower end cover (12). The upper insulation plate (17) and the lower insulation plate (18) press the hollow tube tightly.

10. The condensing heat exchanger according to claim 1, characterized in that, The corrugated pipe (2) has a liquid inlet (21) at one end near the air outlet (121) and a liquid outlet (22) at the other end near the air inlet (111).

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