Heat exchanger for boiler waste heat recovery

Abstract

The utility model relates to the technical field of boilers, in particular to a boiler waste heat recovery heat exchanger which comprises a heat storage water tank, a water return pipe arranged at the bottom of the rear side of the heat storage water tank, a heat exchange water tank arranged at the top of the heat storage water tank and a pump body arranged at the top of the heat exchange water tank. The output end of the pump body communicates with the heat exchange water tank through a liquid conveying pipe, a smoke inlet pipe is arranged in the middle of the left side of the heat exchange water tank, a smoke outlet pipe is arranged in the middle of the right side of the heat exchange water tank, and a smoke channel is formed in the heat exchange water tank and comprises a rectangular smoke inlet box and a rectangular smoke outlet box. According to the heat exchanger for boiler waste heat recovery, by arranging the temperature controller and the electromagnetic valve, the system can automatically detect the water temperature in the heat storage water tank. When the water temperature is lower than a set threshold value, the pump body is started, water is fed into the heat exchange water tank to be circularly heated, it is guaranteed that the temperature of hot water in the hot water storage tank is within a set range all the time, and continuous and stable hot water supply is provided.

Description

Technical Field

[0001] The utility model relates to the technical field of boilers, in particular to a heat exchanger for recovering waste heat from a boiler. Background Art

[0002] At present, industrial boilers are widely used in power generation, heating and industrial production. However, a large amount of flue gas is generated during the operation of the boiler, which contains a large amount of heat energy. If it is not utilized, it will not only cause energy waste, but also increase environmental pollution. With the shortage of energy resources and the enhancement of environmental protection awareness, how to efficiently recycle and utilize the waste heat in boiler flue gas has become an urgent problem to be solved.

[0003] The patent with publication number CN220119408U discloses a heat pipe heat exchanger for recovering waste heat from boiler flue gas, including a boiler and a recovery heat pipe heat exchanger. The utility model recovers the boiler flue gas once by firstly arranging square tubes side by side and by reversely flowing the flue gas and cooling water in the tubes in a primary heat exchanger, and then performs secondary heat recovery by wrapping a hexagonal tube for circulating flue gas in all directions through a plurality of hexagonal tubes for circulating cold air in a secondary heat exchanger, thereby completing sufficient heat recovery of the boiler flue gas in a compact structure, thereby solving the problem of wasting energy and polluting the environment when emitting high-temperature flue gas from small boilers and household boilers.

[0004] Although the above-mentioned prior art can recycle the waste heat of flue gas, when the water in the primary heat exchanger does not reach the specified temperature, it cannot be circulated and heated through the primary heat exchanger, and the water temperature may be insufficient before it is output. Moreover, since the boiler flue gas outlet is directly connected to the flue gas square pipe inlet, the flue gas contains a lot of particulate matter. After long-term use, larger particulate matter may cause multiple square pipes to be blocked, affecting the heat exchange efficiency and system stability. In view of this, we propose a heat exchanger for boiler waste heat recovery. Utility Model Content

[0005] The purpose of the utility model is to provide a heat exchanger for recovering waste heat from a boiler to solve the problems raised in the above-mentioned background technology.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A heat exchanger for recovering waste heat from a boiler comprises a hot water storage tank for storing hot water and storing heat energy through a heat exchange process to provide storage and circulation of hot water. A first water inlet pipe is provided on the left side of the hot water storage tank and near the top. A first water outlet pipe is provided at the bottom of the front side of the hot water storage tank to output the hot water heated in the hot water storage tank for use. A return pipe is provided at the bottom of the rear side of the hot water storage tank to return the used water to the hot water storage tank for reheating. A hot water exchange tank is provided on the top of the hot water storage tank to cooperate with the hot water storage tank for the heat exchange process to transfer the waste heat in the flue gas to the water. A pump body is provided on the top of the hot water exchange tank. The input end of the pump body is connected to the return pipe through a liquid pumping pipe, and the output end of the pump body is connected to the hot water exchange tank through a liquid delivery pipe.

[0008] A smoke inlet pipe is provided in the middle of the left side of the heat exchange tank to guide the smoke generated by the boiler into the heat exchange tank for waste heat recovery. A second water outlet pipe is provided at the bottom of the left side of the heat exchange tank. The second water outlet pipe is connected with the first water inlet pipe through a U-shaped liquid guide pipe to output the hot water heated in the heat exchange tank and store it in the heat storage tank. A second water inlet pipe is provided on the right side of the heat exchange tank and near the top to introduce cold water into the heat exchange tank for heat exchange. A smoke outlet pipe is provided in the middle of the right side of the heat exchange tank to discharge the smoke after heat exchange out of the heat exchange tank. The smoke outlet pipe is externally connected to a smoke treatment device to prevent smoke from polluting the air.

[0009] The heat exchange tank is provided with a flue gas channel, which guides the flue gas through the heat exchange tank to realize waste heat recovery of the flue gas, and the flue gas channel includes a rectangular smoke inlet box and a rectangular smoke outlet box, the rectangular smoke inlet box is connected with the smoke inlet pipe, receives and distributes the smoke introduced by the smoke inlet pipe, and ensures that the smoke enters multiple smoke ducts, the rectangular smoke outlet box is connected with the smoke outlet pipe, receives and guides the smoke passing through the smoke duct and the filter screen, and guides it to the smoke outlet pipe, a plurality of smoke ducts arranged in a matrix are provided between the rectangular smoke inlet box and the rectangular smoke outlet box, connecting the rectangular smoke inlet box and the rectangular smoke outlet box, and guiding the smoke to exchange heat through the heat exchange tank, and a detachable first particle filter screen plate and a second particle filter screen plate are provided in the rectangular smoke inlet box from left to right, the filter hole size of the first particle filter screen plate is larger than the filter hole size of the second particle filter screen plate, the first particle filter screen plate filters larger particles in the smoke to prevent clogging of the smoke duct and subsequent structures, and the second particle filter screen plate further filters smaller particles in the smoke to ensure the cleanliness of the smoke.

[0010] Preferably, the second water inlet pipe, the U-shaped liquid guiding pipe and the first water outlet pipe are all provided with solenoid valves to facilitate the control of the switching of the second water inlet pipe, the U-shaped liquid guiding pipe and the first water outlet pipe.

[0011] Preferably, a thermostat is provided on the front side of the hot water storage tank, the temperature sensing probe of the thermostat is located in the hot water storage tank, the controller of the pump body is electrically connected to the thermostat through a wire, the thermostat detects whether the temperature of the hot water in the hot water storage tank reaches a set threshold value, when the water temperature is lower than the threshold value, the pump body works to transport the water in the hot water storage tank to the heat exchange tank for circulating heating until the temperature of the hot water in the hot water storage tank reaches the set threshold value.

[0012] Preferably, the front side of the rectangular cigarette inlet box is an open structure, a rectangular opening is opened on the front side of the water exchange water tank and near the left side, the front side of the rectangular cigarette inlet box passes through the rectangular opening, and the connection between the rectangular cigarette inlet box and the rectangular opening is sealed.

[0013] Preferably, a U-shaped limit block is provided on the front side of the water exchange tank and near the top of the rectangular opening, and a support block is provided on the front side of the water exchange tank and near the bottom of the rectangular opening. The support block provides support, and a sealing plug plate is connected to the inner side of the U-shaped limit block to provide a sealing function to prevent smoke leakage and ensure heat exchange efficiency. The U-shaped limit block is used to limit and fix the sealing plug plate to ensure the stability and sealing performance of the sealing plug plate. A positioning slot is provided on the rear side of the top of the support block, and the bottom end of the sealing plug plate is inserted into the positioning slot to fix the bottom end of the sealing plug plate to ensure the stability of the sealing position.

[0014] Preferably, a handle groove is provided on the front side of the sealing plug plate and near the top to facilitate operation and disassembly of the sealing plug plate. A rubber pad is embedded on the rear side of the sealing plug plate. The rear side of the rubber pad fits tightly with the front sides of the first particle filter screen plate and the second particle filter screen plate to provide sealing and buffering effects, thereby ensuring that the sealing plug plate fits tightly with the filter screen plate to prevent air leakage.

[0015] Preferably, a first U-shaped positioning plate is provided on the upper and lower sides of the inner wall of the rectangular cigarette inlet box and close to the left side, and the first particle filter screen plate is slidably connected between the two first U-shaped positioning plates to position and fix the first particle filter screen plate to ensure its stability in the rectangular cigarette inlet box, and a second U-shaped positioning plate is provided on the upper and lower sides of the inner wall of the rectangular cigarette inlet box and close to the right side, and the second particle filter screen plate is slidably connected between the two second U-shaped positioning plates to position and fix the second particle filter screen plate to ensure its stability in the rectangular cigarette inlet box.

[0016] Compared with the prior art, the beneficial effects of the utility model are:

[0017] 1. The heat exchanger for waste heat recovery of the boiler can automatically detect the water temperature in the hot water storage tank by setting the thermostat and solenoid valve. When the water temperature is lower than the set threshold, the pump will start to send water into the hot water exchange tank for circulating heating, ensuring that the hot water temperature in the hot water storage tank is always within the set range, providing a continuous and stable hot water supply.

[0018] 2. The heat exchanger for recovering waste heat from the boiler is equipped with multiple flue gas ducts, and the flue gas channel can effectively transfer the waste heat in the flue gas to water, thereby improving the utilization rate of thermal energy and reducing energy waste.

[0019] 3. The heat exchanger for waste heat recovery of the boiler adopts a dual filtering design of the first particle filter screen and the second particle filter screen. The first particle filter screen filters larger particles to prevent clogging of the flue gas duct; the second particle filter screen further filters smaller particles to ensure the cleanliness of the flue gas, thereby improving the stability of the system and the heat exchange efficiency.

[0020] 4. The heat exchanger for waste heat recovery of the boiler is designed with a detachable particle filter plate and sealing plug plate, which is convenient for users to conduct regular inspection, cleaning and replacement. At the same time, the handle groove design on the sealing plug plate makes the operation more convenient.

[0021] 5. The heat exchanger for waste heat recovery of the boiler adopts a rectangular smoke inlet box and a rectangular smoke outlet box structure, and the smoke duct is arranged in a matrix, with a compact structure and high space utilization. At the same time, the design of the sealing plug plate and rubber pad ensures the good sealing of the heat exchanger, prevents smoke leakage, and improves the heat exchange efficiency.

[0022] 6. The heat exchanger for waste heat recovery from the boiler ensures the stability of the sealing plate and the particle filter screen by setting U-shaped limit blocks, support blocks and positioning slots, avoiding displacement or loosening of components due to vibration or other factors during use, thereby ensuring the reliable operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the overall first-view structure of the utility model;

[0024] Figure 2 It is a schematic diagram of the overall structure of the utility model from a second viewing angle;

[0025] Figure 3 It is one of the partial structural schematic diagrams of the utility model;

[0026] Figure 4 This is the second schematic diagram of the partial structure of the utility model;

[0027] Figure 5 This is a schematic diagram of the smoke channel structure in the utility model;

[0028] In the figure: 1, hot water storage tank; 10, first water inlet pipe; 11, first water outlet pipe; 12, return pipe; 2, hot water exchange tank; 20, smoke inlet pipe; 21, smoke outlet pipe; 22, second water inlet pipe; 23, second water outlet pipe; 24, rectangular opening; 25, U-shaped limit block; 26, support block; 260, positioning slot; 3, smoke channel; 30, rectangular smoke inlet box; 300, first U-shaped positioning plate; 301, second U-shaped positioning plate; 31, rectangular smoke outlet box; 32, smoke duct; 33, first particle filter screen plate; 34, second particle filter screen plate; 4, sealing plug plate; 40, handle groove; 5, pump body; 50, liquid extraction pipe; 51, liquid delivery pipe; 6, rubber pad; 7, U-shaped liquid guide pipe. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0031] See also Figure 1-Figure 5 , the utility model provides a technical solution:

[0032] A heat exchanger for recovering waste heat from a boiler comprises a hot water storage tank 1, which is used to store hot water and store heat energy through a heat exchange process to provide storage and circulation of hot water. A first water inlet pipe 10 is provided on the left side of the hot water storage tank 1 and near the top. A first water outlet pipe 11 is provided at the bottom of the front side of the hot water storage tank 1 to output the hot water heated in the hot water storage tank 1 for use. A return pipe 12 is provided at the bottom of the rear side of the hot water storage tank 1 to return the used water to the hot water storage tank 1 for reheating. A hot water exchange tank 2 is provided on the top of the hot water storage tank 1 to cooperate with the hot water storage tank 1 for the heat exchange process to transfer the waste heat in the flue gas to the water. A pump body 5 is provided on the top of the hot water exchange tank 2. The input end of the pump body 5 is connected to the return pipe 12 through a liquid pumping pipe 50, and the output end of the pump body 5 is connected to the hot water exchange tank 2 through a liquid delivery pipe 51.

[0033] A smoke inlet pipe 20 is provided in the middle of the left side of the heat exchange water tank 2 to guide the smoke generated by the boiler into the heat exchange water tank 2 for waste heat recovery. A second water outlet pipe 23 is provided at the bottom of the left side of the heat exchange water tank 2. The second water outlet pipe 23 is connected with the first water inlet pipe 10 through the U-shaped liquid guide pipe 7 to output the hot water heated in the heat exchange water tank 2 and store it in the heat storage tank 1. A second water inlet pipe 22 is provided on the right side of the heat exchange water tank 2 and near the top to introduce cold water into the heat exchange water tank 2 for heat exchange. A smoke outlet pipe 21 is provided in the middle of the right side of the heat exchange water tank 2 to discharge the smoke after heat exchange out of the heat exchange water tank 2. The smoke outlet pipe 21 is externally connected to a smoke treatment device to prevent smoke from polluting the air.

[0034] A smoke channel 3 is provided in the heat exchange tank 2 to guide the smoke through the heat exchange tank 2 to realize waste heat recovery of the smoke. The smoke channel 3 includes a rectangular smoke inlet box 30 and a rectangular smoke outlet box 31. The rectangular smoke inlet box 30 is connected to the smoke inlet pipe 20 to receive and distribute the smoke introduced by the smoke inlet pipe 20 to ensure that the smoke enters multiple smoke ducts 32. The rectangular smoke outlet box 31 is connected to the smoke outlet pipe 21 to receive and guide the smoke passing through the smoke duct 32 and the filter plate, and guide it to the smoke outlet pipe 21. A plurality of smoke inlet boxes 30 and 31 arranged in a matrix are provided between the rectangular smoke inlet box 30 and the rectangular smoke outlet box 31. The duct 32 connects the rectangular smoke inlet box 30 and the rectangular smoke outlet box 31, and guides the smoke to exchange heat through the heat exchange water tank 2. The rectangular smoke inlet box 30 is provided with a detachable first particle filter plate 33 and a second particle filter plate 34 from left to right. The filter hole size of the first particle filter plate 33 is larger than the filter hole size of the second particle filter plate 34. The first particle filter plate 33 filters larger particles in the smoke to prevent blockage of the smoke duct 32 and subsequent structures. The second particle filter plate 34 further filters smaller particles in the smoke to ensure the cleanliness of the smoke.

[0035] In this embodiment, solenoid valves are provided on the second water inlet pipe 22 , the U-shaped liquid guiding pipe 7 and the first water outlet pipe 11 to control the opening and closing of the second water inlet pipe 22 , the U-shaped liquid guiding pipe 7 and the first water outlet pipe 11 .

[0036] Specifically, a thermostat is provided on the front side of the hot water storage tank 1, and the temperature sensing probe of the thermostat is located in the hot water storage tank 1. The controller of the pump body 5 is electrically connected to the thermostat through a wire. The thermostat detects whether the temperature of the hot water in the hot water storage tank 1 reaches a set threshold value. When the water temperature is lower than the threshold value, the pump body 5 works to transport the water in the hot water storage tank 1 to the heat exchange tank 2 for circulating heating until the temperature of the hot water in the hot water storage tank 1 reaches the set threshold value.

[0037] Furthermore, the front side of the rectangular cigarette inlet box 30 is an open structure, and a rectangular opening 24 is opened on the front side of the water exchange tank 2 and near the left side. The front side of the rectangular cigarette inlet box 30 passes through the rectangular opening 24, and the connection between the rectangular cigarette inlet box 30 and the rectangular opening 24 is sealed.

[0038] Furthermore, a U-shaped limit block 25 is provided on the front side of the water exchange tank 2 and near the top of the rectangular opening 24, and a support block 26 is provided on the front side of the water exchange tank 2 and near the bottom of the rectangular opening 24. The support block 26 provides support, and a sealing plug plate 4 is connected to the inner side of the U-shaped limit block 25 to provide a sealing function to prevent smoke leakage and ensure heat exchange efficiency. The U-shaped limit block 25 is used to limit and fix the sealing plug plate 4 to ensure the stability and sealing performance of the sealing plug plate. A positioning slot 260 is provided on the rear side of the top of the support block 26, and the bottom end of the sealing plug plate 4 is inserted into the positioning slot 260 to fix the bottom end of the sealing plug plate 4 to ensure the stability of the sealing position.

[0039] Furthermore, a handle groove 40 is provided on the front side of the sealing plug plate 4 and near the top, which is convenient for operating and disassembling the sealing plug plate 4. A rubber pad 6 is embedded on the rear side of the sealing plug plate 4. The rear side of the rubber pad 6 is tightly fitted with the front sides of the first particle filter screen plate 33 and the second particle filter screen plate 34 to provide sealing and buffering effects, thereby ensuring that the sealing plug plate 4 is tightly fitted with the filter screen plate to prevent air leakage.

[0040] Furthermore, a first U-shaped positioning plate 300 is provided on the upper and lower sides of the inner wall of the rectangular cigarette inlet box 30 and is close to the left side. The first particle filter screen plate 33 is slidably connected between the two first U-shaped positioning plates 300, and is used to position and fix the first particle filter screen plate 33 to ensure its stability in the rectangular cigarette inlet box 30. A second U-shaped positioning plate 301 is provided on the upper and lower sides of the inner wall of the rectangular cigarette inlet box 30 and is close to the right side. The second particle filter screen plate 34 is slidably connected between the two second U-shaped positioning plates 301, and is used to position and fix the second particle filter screen plate 34 to ensure its stability in the rectangular cigarette inlet box 30.

[0041] When the heat exchanger for boiler waste heat recovery of this embodiment is in use, the hot water storage tank 1 and the hot water exchange tank 2 are installed in appropriate positions to ensure that they are firmly placed and smoothly connected to the pipes of the boiler and other related equipment, the second water inlet pipe 22 is connected to the cold water source to ensure that cold water can smoothly enter the hot water exchange tank 2, the first water outlet pipe 11 is connected to the water point or heat system for hot water output, the smoke inlet pipe 20 is connected to the smoke exhaust port of the boiler to ensure that the smoke can smoothly enter the hot water exchange tank 2 for waste heat recovery, the smoke outlet pipe 21 is connected to the smoke treatment equipment to ensure that the smoke after heat exchange can be discharged and treated to avoid air pollution, the boiler is started to start running and generate smoke, the water inlet valve of the hot water exchange tank 2 is opened to ensure that cold water can enter the hot water exchange tank 2, the smoke generated by the boiler enters the rectangular smoke inlet box 30 through the smoke inlet pipe 20, and the smoke passes through the first particle filter plate After being filtered by the second particle filter screen 33 and the second particle filter screen 34, the hot water enters the flue gas duct 32. The flue gas duct 32 guides the flue gas into the rectangular smoke outlet box 31, and then is discharged from the heat exchange water tank 2 through the smoke outlet pipe 21. The cold water enters the heat exchange water tank 2 through the second water inlet pipe 22, exchanges heat around the flue gas duct 32, absorbs the residual heat in the flue gas to heat itself, and the heated hot water enters the U-shaped liquid guide pipe 7 through the second water outlet pipe 23, and then enters the heat exchange water tank 1 through the first water inlet pipe 10 for storage. The target water temperature threshold in the heat storage water tank 1 is set by the thermostat, and it is ensured that the temperature sensing probe of the thermostat is correctly installed inside the heat storage water tank 1 so as to monitor the water temperature in real time. When the thermostat detects that the water temperature in the heat storage water tank 1 is lower than the set threshold, the pump body 5 is automatically started, and the pump body 5 draws the water in the heat storage water tank 1 through the liquid extraction pipe 50, and then sends the water to the heat exchange water tank 2 through the liquid delivery pipe 51 for heating. Regularly check the first particle filter screen plate 33 and the second particle filter screen plate 34 to ensure that there is no blockage, open the sealing plug plate 4, take it out through the handle groove 40, check and clean the first particle filter screen plate 33 and the second particle filter screen plate 34, if it is found that the first particle filter screen plate 33 and the second particle filter screen plate 34 are damaged or seriously blocked, they need to be replaced in time, take out and install the first particle filter screen plate 33 and the second particle filter screen plate 34 through the sliding connection to ensure that they are stably placed in the rectangular cigarette inlet box 30.

[0042] The above shows and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the utility model and are not used to limit the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the attached claims and their equivalents.

Claims

1. A heat exchanger for recovering waste heat from a boiler, comprising a hot water storage tank (1), characterized in that: A first water inlet pipe (10) is provided on the left side of the heat storage tank (1) and near the top, a first water outlet pipe (11) is provided at the bottom of the front side of the heat storage tank (1), a return pipe (12) is provided at the bottom of the rear side of the heat storage tank (1), a heat exchange tank (2) is provided on the top of the heat storage tank (1), a pump body (5) is provided on the top of the heat exchange tank (2), the input end of the pump body (5) is connected to the return pipe (12) through a liquid extraction pipe (50), the output end of the pump body (5) is connected to the heat exchange tank (2) through a liquid delivery pipe (51), a smoke inlet pipe (20) is provided in the middle of the left side of the heat exchange tank (2), a second water outlet pipe (23) is provided at the bottom of the left side of the heat exchange tank (2), the second water outlet pipe (23) is connected to the heat exchange tank (2) through a U-shaped liquid guide pipe (7 ) is connected to the first water inlet pipe (10), a second water inlet pipe (22) is provided on the right side of the heat exchange tank (2) and near the top, a smoke outlet pipe (21) is provided in the middle of the right side of the heat exchange tank (2), a smoke passage (3) is provided in the heat exchange tank (2), the smoke passage (3) comprises a rectangular smoke inlet box (30) and a rectangular smoke outlet box (31), the rectangular smoke inlet box (30) is connected to the smoke inlet pipe (20), the rectangular smoke outlet box (31) is connected to the smoke outlet pipe (21), a plurality of smoke ducts (32) arranged in a matrix are provided between the rectangular smoke inlet box (30) and the rectangular smoke outlet box (31), and a detachable first particle filter screen plate (33) and a second particle filter screen plate (34) are provided in the rectangular smoke inlet box (30) from left to right.

2. The heat exchanger for recovering waste heat from a boiler according to claim 1, characterized in that: The second water inlet pipe (22), the U-shaped liquid guide pipe (7) and the first water outlet pipe (11) are all provided with solenoid valves.

3. The heat exchanger for recovering waste heat from a boiler according to claim 2, characterized in that: A thermostat is provided on the front side of the hot water storage tank (1); a temperature sensing probe of the thermostat is located inside the hot water storage tank (1); and a controller of the pump body (5) is electrically connected to the thermostat via a wire.

4. The heat exchanger for recovering waste heat from a boiler according to claim 1, characterized in that: The front side of the rectangular cigarette inlet box (30) is an open structure, a rectangular opening (24) is provided on the front side of the water exchange tank (2) and close to the left side, the front side of the rectangular cigarette inlet box (30) passes through the rectangular opening (24), and the connection between the rectangular cigarette inlet box (30) and the rectangular opening (24) is sealed.

5. The heat exchanger for recovering waste heat from a boiler according to claim 4, characterized in that: A U-shaped limit block (25) is provided on the front side of the water exchange tank (2) and near the top of the rectangular opening (24); a support block (26) is provided on the front side of the water exchange tank (2) and near the bottom of the rectangular opening (24); a sealing plug plate (4) is connected to the inner side of the U-shaped limit block (25); a positioning slot (260) is provided on the rear side of the top of the support block (26); and the bottom end of the sealing plug plate (4) is inserted into the positioning slot (260).

6. The heat exchanger for recovering waste heat from a boiler according to claim 5, characterized in that: A handle groove (40) is provided on the front side of the sealing plug plate (4) and near the top, and a rubber pad (6) is embedded on the rear side of the sealing plug plate (4), and the rear side of the rubber pad (6) is tightly fitted with the front sides of the first particle filter screen plate (33) and the second particle filter screen plate (34).

7. The heat exchanger for recovering waste heat from a boiler according to claim 1, characterized in that: A first U-shaped positioning plate (300) is provided on both upper and lower sides of the inner wall of the rectangular cigarette inlet box (30) and close to the left side, and the first particle filter screen plate (33) is slidably connected between the two first U-shaped positioning plates (300). A second U-shaped positioning plate (301) is provided on both upper and lower sides of the inner wall of the rectangular cigarette inlet box (30) and close to the right side, and the second particle filter screen plate (34) is slidably connected between the two second U-shaped positioning plates (301).

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