A self-cleaning air preheater

Abstract

The present invention relates to the field of heat exchangers, and specifically discloses a self-cleaning air preheater, wherein a smoke inlet is provided at the top of a heat exchange chamber, a smoke exhaust port is provided at the bottom of the heat exchange chamber, a plurality of heat exchange tubes are arranged horizontally in the heat exchange chamber, baffles are provided at both ends of the heat exchange tubes, openings corresponding to the number of heat exchange tubes are provided on the baffles, the heat exchange tubes include an upper heat exchange tube and a lower heat exchange tube, an air inlet is provided at one end of the lower heat exchange tube, an air exhaust port is provided at the same end of the upper heat exchange tube, an air transfer chamber is provided at the other end of the lower heat exchange tube and the upper heat exchange tube, and the air inlet, the lower heat exchange tube, the air transfer chamber, the upper heat exchange tube and the air exhaust port constitute an air heat exchange channel. The present invention achieves the purpose of strengthening heat transfer by increasing the heat transfer coefficient and the heat transfer temperature difference, and a dust cleaning device is provided on the heat exchanger to reduce the dust accumulation phenomenon of the heat exchange tube, thereby further improving the heat exchange efficiency of the air preheater.

Description

Technical Field

[0001] The invention relates to the technical field of heat exchangers, and in particular to a self-cleaning air preheater. Background Art

[0002] There are many types of air preheaters, including rotary air preheaters, plate air preheaters and shell and tube air preheaters. Among them, shell and tube air preheaters have perfect theoretical research and design technology, good application reliability, and are the most widely used. Common shell and tube air preheaters use the high-temperature flue gas generated in industrial production to exchange heat energy with air, and then effectively recover the waste heat of the flue gas to achieve the purpose of energy reuse. However, the heat exchange efficiency of traditional shell and tube air preheaters is not high, the heat utilization rate is low, and the waste heat recovery effect is average. Summary of the invention

[0003] In view of the defects of the above-mentioned prior art, the present invention provides a self-cleaning air preheater, which effectively improves the heat exchange efficiency of the shell and tube air preheater by cleverly arranging the structures of the air channel and the flue gas channel and providing an automatic dust cleaning device.

[0004] The technical solution adopted by the present invention to solve its technical problem is:

[0005] A self-cleaning air preheater comprises a heat exchange chamber, a smoke inlet is provided at the top of the heat exchange chamber, a smoke exhaust port is provided at the bottom of the heat exchange chamber, the smoke inlet, the heat exchange chamber and the smoke exhaust port form a high-temperature smoke channel; a plurality of heat exchange tubes are horizontally arranged in the heat exchange chamber, partitions are provided at both ends of the heat exchange tubes, openings corresponding to the number of heat exchange tubes are provided on the partitions, the heat exchange tubes comprise an upper heat exchange tube and a lower heat exchange tube, one end of the lower heat exchange tube is provided with an air inlet, the same end of the upper heat exchange tube is provided with an air exhaust port, the other ends of the lower heat exchange tube and the upper heat exchange tube are provided with an air transfer chamber, the air inlet, the lower heat exchange tube, the air transfer chamber, the upper heat exchange tube and the air exhaust port form an air heat exchange channel.

[0006] Furthermore, there are multiple heat exchange chambers which are connected in pairs, and the heat exchange tubes horizontally penetrate the multiple heat exchange chambers. The heat exchange tubes include an upper heat exchange tube and a lower heat exchange tube. An air inlet is provided at one end of the lower heat exchange tube, and an air exhaust port is provided at the same end of the upper heat exchange tube. The air transfer chamber is provided at the other end of the lower heat exchange tube and the upper heat exchange tube. The partition is provided between the two adjacent heat exchange chambers. Smoke transfer chambers are provided at the top and bottom ends of the heat exchange chambers. The smoke inlet, heat exchange chamber, smoke transfer chamber and smoke exhaust port constitute a high-temperature smoke channel.

[0007] Furthermore, the air inlet, the lower heat exchange tube, the air transfer chamber, the upper heat exchange tube and the air exhaust port constitute an air heat exchange channel.

[0008] Preferably, the aperture of the opening is not less than the diameter of the heat exchange tube.

[0009] Furthermore, it also includes a cleaning device, which includes a first driving plate, a second driving plate, a cleaning ring and a power mechanism. The first driving plate and the second driving plate are each provided with a plurality of through holes, the heat exchange tube is inserted into the through holes, the cleaning ring is arranged between the first driving plate and the second driving plate and is movably sleeved on the heat exchange tube, the power mechanism connects the first driving plate and the second driving plate, and the first driving plate or the second driving plate is driven by the power mechanism to drive the cleaning ring to move along the outer wall of the heat exchange tube.

[0010] Furthermore, there are multiple cleaning rings, and each of the heat exchange tubes is sleeved with the cleaning ring.

[0011] Further, the number of through holes on the first driving plate is consistent with the number of the heat exchange tubes, and the number of through holes on the second driving plate is consistent with the number of the heat exchange tubes.

[0012] Furthermore, the inner diameter of the cleaning ring is larger than the diameter of the heat exchange tube, and the outer diameter of the cleaning ring is larger than the aperture of the through hole.

[0013] Furthermore, travel switches are provided at both ends of the heat exchange tube near the power mechanism.

[0014] Furthermore, the power mechanism includes a motor, a sprocket and a chain, the sprockets are arranged at both ends of the chain, a driving arm is provided on the chain, and the chain is connected to the first driving plate and the second driving plate through the driving arm.

[0015] The beneficial effects of the present invention are:

[0016] 1. The present invention cleverly designs the high-temperature flue gas channel and the air heat exchange channel, divides the air into two layers for heating, and adopts countercurrent heat exchange, so that the high-temperature flue gas just entering the heat exchange chamber directly heats the preheated air, increases the heat transfer temperature difference, improves the heat transfer efficiency, and recovers waste heat more effectively.

[0017] 2. A dust cleaning device is installed on the air preheater to reduce dust accumulation on the heat exchange tubes and further improve the heat exchange efficiency of the air preheater.

[0018] 3. Set up multiple heat exchange chambers and flue gas transfer chambers, and connect the heat exchange chambers side by side. At the same time, increase the air flow rate and improve the turbulence effect of the flue gas. This setting increases the pipe path of high-temperature flue gas entering the heat exchange chamber, improves the heat transfer coefficient, and thus improves the heat exchange efficiency of the air preheater. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of Example 1.

[0020] Figure 2 It is a partial structural diagram of Example 1.

[0021] Figure 3 yes Figure 2 Side view of the structure.

[0022] Figure 4 yes Figure 2 Exploded view of the structure.

[0023] Figure 5 It is a schematic diagram of the structure of an air preheater with a dust cleaning device.

[0024] Figure 6 It is a side view of the air preheater with a dust removal device.

[0025] Figure 7 yes Figure 6 Enlarged view of the marked part.

[0026] Figure 8 This is a top view of the air preheater with a dust removal device.

[0027] Fig. 9 It is a combination diagram of the heat exchange tube and the drive plate.

[0028] Fig.10 It is a schematic diagram of the structure of the drive plate and the cleaning ring.

[0029] Fig.11 It is a structural diagram of the driver board.

[0030] Fig.12 It is one of the structural diagrams of the power mechanism.

[0031] Fig.13 This is the second structural diagram of the power mechanism.

[0032] Fig.14 It is a structural schematic diagram of Example 2.

[0033] In the figure, 1. heat exchange chamber, 2. flue gas inlet, 3. flue gas exhaust port, 4. heat exchange tube, 41. upper heat exchange tube, 42. lower heat exchange tube, 5. partition, 51. opening, 6. air inlet, 7. air exhaust port, 8. air transfer chamber, 9. flue gas transfer chamber, 10. dust cleaning device, 101. first drive plate, 102. second drive plate, 103. dust cleaning ring, 104. power mechanism, 1041. motor, 1042. sprocket, 1043. chain, 1044. first reducer, 1045. angle converter, 1046. cross universal coupling, 1047. second reducer, 1048. power transmission shafts on both sides, 1049. drive arm, 1050. chain box, 105. through hole, 106. travel switch. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0035] Example 1

[0036] like Figure 1-4 As shown, the self-cleaning air preheater includes a heat exchange chamber 1, a smoke inlet 2 is provided at the top of the heat exchange chamber 1, a smoke exhaust port 3 is provided at the bottom of the heat exchange chamber 1, and the smoke inlet 2, the heat exchange chamber 1 and the smoke exhaust port 3 form a high-temperature smoke channel. A plurality of heat exchange tubes 4 are arranged horizontally in the heat exchange chamber 1, and baffles 5 are provided at both ends of the heat exchange tubes 4. The baffles 5 are provided with openings 51 corresponding to the number of the heat exchange tubes 4, wherein the aperture of the openings 51 is not less than the diameter of the heat exchange tubes 4, and the heat exchange tubes 4 include an upper heat exchange tube 41 and a lower heat exchange tube 42, an air inlet 6 is provided at one end of the lower heat exchange tube 42, and an air exhaust port 7 is provided at the same end of the upper heat exchange tube 41, and an air transfer chamber 8 is provided at the other end of the lower heat exchange tube 42 and the upper heat exchange tube 41, and the air inlet 6, the lower heat exchange tube 42, the air transfer chamber 8, the upper heat exchange tube 41 and the air exhaust port 7 form an air heat exchange channel.

[0037] Heat exchange process:

[0038] Combination Figure 1 As indicated by the middle arrow, air enters the lower heat exchange tube 42 from the air inlet 6, then flows into the air transfer chamber 8, enters the upper heat exchange tube 41 after passing through the air transfer chamber 8, and finally flows out from the air exhaust port 7. At the same time, the high-temperature flue gas enters the heat exchange chamber 1 from the flue gas inlet 2, passes through the upper heat exchange tube 41 and the lower heat exchange tube 42 in sequence, exchanges heat with the air in the upper heat exchange tube 41 and the lower heat exchange tube 42 respectively, and finally is discharged from the flue gas exhaust port 3.

[0039] Heat exchange principle:

[0040] There are three main ways to enhance heat transfer in air preheaters, namely increasing the heat transfer coefficient, increasing the heat transfer temperature difference and expanding the heat transfer area.

[0041] This embodiment mainly improves the heat transfer efficiency by increasing the heat transfer temperature difference: the higher the temperature of the air, the more difficult it is to heat it. This embodiment cleverly designs the high-temperature flue gas channel and the air heat exchange channel, and divides the air into two layers for heating. The air exhaust port is set at the upper layer and the flue gas inlet is set at the top of the air preheater. This setting allows the high-temperature flue gas that has just entered the air preheater to heat the upper layer of air. The high-temperature flue gas enters the lower layer of heat exchange tubes after passing through the upper layer of heat exchange tubes. At this time, the waste heat of the flue gas continues to heat the lower layer of air, and the lower layer of air, after being preheated, passes through the air transfer chamber 8 to become the upper layer of air, and the cycle continues. This embodiment adopts countercurrent heat exchange, so that the high-temperature flue gas that has just entered the heat exchange chamber 1 directly heats the preheated air, increases the heat transfer temperature difference, and recovers waste heat more effectively.

[0042] The use of shell and tube air preheaters can effectively solve the problem of flue gas waste heat recovery. However, the high-temperature flue gas generated by industry contains a large amount of dust or debris. During the waste heat recovery process, the dust or debris can easily be adsorbed or adhered to the outer wall of the heat exchange tube. Long-term dust accumulation will reduce the heat exchange efficiency of the air preheater and seriously affect the normal use of the air preheater.

[0043] like Figure 5-11 As shown, in order to further improve the heat exchange efficiency of the air preheater, the present embodiment further includes a dust cleaning device 10, which includes a first drive plate 101, a second drive plate 102, a dust cleaning ring 103 and a power mechanism 104. The first drive plate 101 and the second drive plate 102 are both provided with a plurality of through holes 105, and the heat exchange tube 4 is inserted into the through holes 105. The dust cleaning ring 103 is arranged between the first drive plate 101 and the second drive plate 102 and is movably sleeved on the heat exchange tube 4. The number of through holes 105 on the first drive plate 101 is consistent with the number of heat exchange tubes 4, the number of through holes 105 on the second drive plate 102 is consistent with the number of heat exchange tubes 4, and travel switches 106 are provided at both ends of the heat exchange tube 4 near the power mechanism 104.

[0044] When installing the cleaning device 10, first, align the through hole 105 on the first driving plate 101 with the corresponding heat exchange tube 4, and insert the first driving plate 101 from one end of the heat exchange tube 4, then, insert the cleaning ring 103 into the heat exchange tube 4 one by one, ensuring that each heat exchange tube 4 is covered with a cleaning ring 103, then, align the through hole 105 on the second driving plate 102 with the corresponding heat exchange tube 4, and insert the second driving plate 102 from one end of the heat exchange tube 4, ensuring that the cleaning ring 103 is between the first driving plate 101 and the second driving plate 102, and the first driving plate 101 and the second driving plate 102 are combined into a whole through four axes, and finally, the power mechanism 104 connects the first driving plate 101 and the second driving plate 102, ensuring that the first driving plate 101 and the second driving plate 102 are driven by the power mechanism 104 to drive the cleaning ring 103 to move along the outer wall of the heat exchange tube 4.

[0045] Depend on Figure 6-7 It can be seen that there are multiple cleaning rings 103, and each outer wall of the heat exchange tube 4 is covered with a cleaning ring 103. The cleaning rings 103 do not interfere with each other, so the damage or failure of one cleaning ring 103 will not affect the use of other cleaning rings 103. The inner diameter of the cleaning ring 103 is larger than the diameter of the heat exchange tube 4, and the outer diameter of the cleaning ring 103 is larger than the aperture of the through hole 105. The cleaning ring 103 is strictly controlled between the first driving plate 101 and the second driving plate 102, is not connected to the power mechanism 104, and cannot move independently and regularly on the outer wall of the heat exchange tube 4. It can only be forced to move when the first driving plate 101 or the second driving plate 102 moves, thereby continuously scraping off the dust on the outer wall of the heat exchange tube 4 to ensure the heat exchange efficiency of the air preheater.

[0046] Figure 7 In the embodiment, the cleaning ring 103 is movably mounted on the heat exchange tube 4, and there is a gap of 1 to 3 mm between the cleaning ring 103 and the heat exchange tube 4. Even if the heat exchange tube 4 is bent, the cleaning ring 103 will not be stuck. The heat exchange tube 4 is inserted into the through hole 105 on the first drive plate 101 and the second drive plate 102. There is a large gap between the through hole 105 and the heat exchange tube 4. The first drive plate 101 and the second drive plate 102 will not be stuck and fail due to the bending or deformation of the heat exchange tube 4. It is only necessary to ensure that the aperture of the through hole 105 is smaller than the outer diameter of the cleaning ring 103. The specific shape and size of the aperture of the through hole 105 are not strictly required, and the processing and manufacturing are simple. Preferably, the outer diameter of the cleaning ring 103 is 10 to 28 mm larger than the aperture of the through hole 105.

[0047] from Figure 12-13It can be seen that the power mechanism 104 includes a motor 1041, a sprocket 1042 and a chain 1043. The sprocket 1042 is arranged at both ends of the chain 1043. The chain 1043 is connected to the first drive plate 101 and the second drive plate 102 through a driving arm 1049. In order to optimize the structure of the power mechanism 104, the number of motors 1041 is set to 1 in this embodiment. The air preheater is provided with power transmission shafts 1048 on both sides in the vertical direction of the movement of the driving plate. One end of the power transmission shafts 1048 on both sides is connected to a first reducer 1044, and the first reducer 1044 is connected to the motor 1041. Angle converters 1045 are provided at both ends of the power transmission shafts 1048 on both sides. The lower end of the angle converter 1045 is connected to a cross universal coupling 1046. The cross universal coupling 1046 is provided with a second reducer 1047 near the sprocket 1042, and the second reducer 1047 is connected to the sprocket 1042.

[0048] The process of the power mechanism 104 driving the driving plate:

[0049] After being decelerated by the first reducer 1044, the motor 1041 outputs rotational power to both ends of the first reducer 1044, and the power transmission shafts 1048 on both sides transmit the power to the angle converters 1045 at both ends respectively. After that, the power is transmitted to the cross universal coupling 1046 through the angle converter 1045. After receiving the driving force, the cross universal coupling 1046 transmits the power to the sprocket 1042 through the second reducer 1047. After the sprocket 1042 rotates, it pulls the chain 1043 to move. The chain 1043 further drives the first drive plate 1 and the second drive plate 2 to move back and forth between the travel switch 106 through the drive arm 1049, continuously removing dust from the outer wall of the heat exchange tube 4.

[0050] The steps of using the above-mentioned cleaning device 10 to clean the heat exchange tube 4 are as follows:

[0051] S1: The power mechanism 104 drives the first driving plate 101 and the second driving plate 102. The first driving plate 101 pushes the cleaning ring 103 to move toward one end of the heat exchange tube 4. The cleaning ring 103 scrapes away the dust on the heat exchange tube 4.

[0052] S2: The first driving plate 101 pushes the cleaning ring 103 to move to the travel switch 106 at one end of the heat exchange tube 4 and stops moving;

[0053] S3: The power mechanism 104 drives the first driving plate 101 and the second driving plate 102, and the second driving plate 102 pushes the cleaning ring 103 to move toward the other end of the heat exchange tube 4, and the cleaning ring 103 scrapes off the dust on the heat exchange tube 4;

[0054] S4: The second driving plate 102 pushes the cleaning ring 103 to move to the travel switch 106 at the other end of the heat exchange tube 4 and stops moving;

[0055] S5: Repeat the above steps.

[0056] The above-mentioned dust cleaning device 10 achieves the following beneficial effects:

[0057] 1. The cleaning ring 103 is movably sleeved on the heat exchange tube 4 and is arranged between two driving plates. The driving plates move to drive the cleaning ring 103 to move back and forth on the outer wall of the heat exchange tube 4, continuously scraping off the dust on the outer wall of the heat exchange tube 4 to ensure the heat exchange efficiency of the heat exchange tube 4. The structure is simple and the design is ingenious.

[0058] 2. A through hole 105 is provided on the driving plate, and the aperture of the through hole 105 is smaller than the outer diameter of the cleaning ring 103. During the cleaning process, the cleaning ring 103 is strictly controlled between the two driving plates to ensure that the cleaning ring 103 moves with the movement of the driving plates.

[0059] 3. A cleaning ring 103 is sleeved on the outer wall of each heat exchange tube 4. The cleaning rings 103 do not interfere with each other. The damage or failure of one cleaning ring 103 will not affect the use of other cleaning rings 103. The maintenance is simple, economical and practical.

[0060] 4. The cleaning ring 103 is movably mounted on the heat exchange tube 4. There is a gap of 1 to 3 mm between the cleaning ring 103 and the heat exchange tube 4. Even if the heat exchange tube 4 is bent, the cleaning ring 103 will not be stuck, and the practicability is strong.

[0061] 5. The heat exchange tube 4 is inserted into the through hole 105 on the driving plate. There is a large gap between the through hole 105 and the heat exchange tube 4. The driving plate will not be stuck and fail due to the bending or deformation of the heat exchange tube 4. It only needs to ensure that the aperture of the through hole 105 is smaller than the outer diameter of the cleaning ring 103. There are no strict requirements on the specific shape and size of the aperture of the through hole 105. The design is reasonable and the processing and manufacturing are simple.

[0062] In summary, this embodiment cleverly designs the internal structure of the air preheater itself, and achieves the effect of enhancing heat transfer by increasing the heat transfer temperature difference. In addition, a dust cleaning device 10 is provided on the air preheater to reduce dust accumulation on the heat exchange tube 4, thereby further improving the heat exchange efficiency of the air preheater.

[0063] Example 2

[0064] like Fig.14As shown, this embodiment includes three heat exchange chambers 1 which are connected in parallel in pairs, and a plurality of heat exchange tubes 4 horizontally penetrate the three heat exchange chambers 1. Partition plates 5 are provided at both ends of the heat exchange tubes 4 and between two adjacent heat exchange chambers 1. The partition plates 5 are provided with openings 51 corresponding to the number of the heat exchange tubes 4, wherein the aperture of the openings 51 is not less than the diameter of the heat exchange tubes 4. The heat exchange tubes 4 include an upper heat exchange tube 41 and a lower heat exchange tube 42. An air inlet 6 is provided at one end of the lower heat exchange tube 42, and an air exhaust port 7 is provided at the same end of the upper heat exchange tube 41. An air transfer chamber 8 is provided at the other ends of the lower heat exchange tube 42 and the upper heat exchange tube 41. The air inlet 6, the lower heat exchange tube 42, the air transfer chamber 8, the upper heat exchange tube 41 and the air exhaust port 7 constitute an air heat exchange channel.

[0065] A smoke inlet 2 is provided at the top of the heat exchange chamber 1 on the side of the air exhaust port 6, a smoke exhaust port 3 is provided at the bottom of the heat exchange chamber 1 on the side of the air transfer chamber 8, and a smoke transfer chamber 9 is also provided at the top and bottom of the heat exchange chamber 1. The smoke inlet 2, the heat exchange chamber 1, the smoke transfer chamber 9 and the smoke exhaust port 3 constitute a high-temperature smoke channel.

[0066] Heat exchange process:

[0067] Combination Figure 1 As indicated by the middle arrow, air enters the lower heat exchange tube 42 from the air inlet 6, then flows into the air transfer chamber 8, enters the upper heat exchange tube 41 after passing through the air transfer chamber 8, and finally flows out from the air exhaust port 7. Fig.14 As indicated by the middle arrow, the high-temperature flue gas enters the heat exchange chamber 1 from the flue gas inlet 2, exchanges heat with the air in the heat exchange tube 4, passes through the flue gas transfer chamber 9 at the bottom and top of the heat exchange chamber 1 and multiple heat exchange chambers 1, and is finally discharged from the flue gas exhaust port.

[0068] Heat exchange principle:

[0069] This embodiment improves the heat transfer efficiency by increasing the heat transfer coefficient and increasing the heat transfer temperature difference:

[0070] 1. This embodiment increases the turbulence effect of the flue gas by increasing the air velocity and the number of heat exchange chambers 1. This arrangement increases the tube path for high-temperature flue gas to enter the heat exchange chamber 1 and increases the heat transfer coefficient, i.e., the tube path heat transfer is enhanced;

[0071] 2. The higher the air temperature, the harder it is to heat. This embodiment cleverly designs the high-temperature flue gas channel and the air heat exchange channel, and heats the air in two layers. The air exhaust port is located at the upper layer and the flue gas inlet is located at the top of the air preheater. This setting allows the high-temperature flue gas that has just entered the air preheater to heat the upper air. This embodiment adopts countercurrent heat exchange, so that the high-temperature flue gas that has just entered the heat exchange chamber 1 directly heats the preheated air, increases the heat transfer temperature difference, and recovers waste heat more effectively.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should fall within the protection scope of the present invention.

Claims

1. A self-cleaning air preheater, comprising a heat exchange chamber (1), characterized in that: The top end of the heat exchange chamber (1) is provided with a smoke inlet (2), and the bottom end of the heat exchange chamber (1) is provided with a smoke exhaust port (3), wherein the smoke inlet (2), the heat exchange chamber (1) and the smoke exhaust port (3) form a high-temperature smoke passage; A plurality of heat exchange tubes (4) are arranged in the horizontal direction in the heat exchange chamber (1), partitions (5) are provided at both ends of the heat exchange tubes (4), and openings (51) corresponding to the number of the heat exchange tubes (4) are provided on the partitions (5), and the heat exchange tubes (4) include an upper heat exchange tube (41) and a lower heat exchange tube (42), one end of the lower heat exchange tube (42) is provided with an air inlet (6), and the same end of the upper heat exchange tube (41) is provided with an air exhaust port (7), and the other ends of the lower heat exchange tube (42) and the upper heat exchange tube (41) are provided with an air transfer chamber (8), and the air inlet (6), the lower heat exchange tube (42), the air transfer chamber (8), the upper heat exchange tube (41) and the air exhaust port (7) constitute an air heat exchange channel; It also comprises a cleaning device (10), the cleaning device (10) comprising a first driving plate (101), a second driving plate (102), a cleaning ring (103) and a power mechanism (104), the first driving plate (101) and the second driving plate (102) are both provided with a plurality of through holes (105), the heat exchange tube (4) is inserted into the through holes (105), the cleaning ring (103) is arranged between the first driving plate (101) and the second driving plate (102) and is movably sleeved on the heat exchange tube (4), the power mechanism (104) connects the first driving plate (101) and the second driving plate (102), and the first driving plate (101) or the second driving plate (102) is driven by the power mechanism (104) to drive the cleaning ring (103) to move along the outer wall of the heat exchange tube (4); The heat exchange chambers (1) are multiple and are connected in pairs. The heat exchange tubes (4) horizontally penetrate the multiple heat exchange chambers (1). The heat exchange tubes (4) include an upper heat exchange tube (41) and a lower heat exchange tube (42). One end of the lower heat exchange tube (42) is provided with an air inlet (6). The same end of the upper heat exchange tube (41) is provided with an air exhaust port (7). The other ends of the lower heat exchange tube (42) and the upper heat exchange tube (41) are provided with the air transfer chamber (8). The partition plate (5) is provided between two adjacent heat exchange chambers (1). The top and bottom ends of the heat exchange chambers (1) are provided with smoke transfer chambers (9). The smoke inlet (2), the heat exchange chamber (1), the smoke transfer chamber (9) and the smoke exhaust port (3) constitute a high-temperature smoke passage.

2. A self-cleaning air preheater according to claim 1, characterized in that: The air inlet (6), the lower heat exchange tube (42), the air transfer chamber (8), the upper heat exchange tube (41) and the air exhaust port (7) constitute an air heat exchange channel.

3. A self-cleaning air preheater according to claim 1, characterized in that: The aperture of the opening (51) is not less than the diameter of the heat exchange tube (4).

4. A self-cleaning air preheater according to claim 1, characterized in that: There are a plurality of cleaning rings (103), and each heat exchange tube (4) is sleeved with a cleaning ring (103).

5. A self-cleaning air preheater according to claim 4, characterized in that: The number of through holes (105) on the first driving plate (101) is consistent with the number of the heat exchange tubes (4), and the number of through holes (105) on the second driving plate (102) is consistent with the number of the heat exchange tubes (4).

6. A self-cleaning air preheater according to claim 4, characterized in that: The inner diameter of the cleaning ring (103) is greater than the diameter of the heat exchange tube (4), and the outer diameter of the cleaning ring (103) is greater than the aperture of the through hole (105).

7. A self-cleaning air preheater according to claim 4, characterized in that: Travel switches (106) are provided at both ends of the heat exchange tube (4) near the power mechanism (104).

8. A self-cleaning air preheater according to claim 4, characterized in that: The power mechanism (104) comprises a motor (1041), a sprocket (1042) and a chain (1043); the sprocket (1042) is arranged at both ends of the chain (1043); a driving arm (1049) is provided on the chain (1043); and the chain (1043) is connected to the first driving plate (101) and the second driving plate (102) via the driving arm (1049).

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