Heat exchange tube for MGGH flue gas heat exchanger device

Abstract

The invention provides a heat exchange tube used for an MGGH flue gas heat exchanger device, and relates to the field of flue gas heat exchangers, the heat exchange tube used for the MGGH flue gas heat exchanger device comprises a tube body, the inner wall of the tube body is fixedly provided with a fixed part used for ventilation, and the inner wall of the tube body is slidably provided with a sliding part used for ventilation; a telescopic mechanism used for air inlet is installed between the fixed part and the sliding part, and a flow deflector used for stretching is installed between the pipe body and the telescopic mechanism. According to the heat exchange tube for the MGGH flue gas heat exchanger device, by arranging the spiral flow deflectors, the retention time of flue gas in the tube body is long, the flow velocity is increased, the tube wall of the tube body can make full contact with the flue gas, and when the flue gas contains many smoke particles, the direct contact opportunities of the particles, the inner wall of the tube body and the flow deflectors are increased, so that the heat exchange efficiency is improved. The particles continuously collide and rub the inner wall of the pipe body and the surfaces of the flow deflectors in the flowing process, so that the overall friction force is increased, the generated temperature is increased, and the heat utilization rate is further increased.

Description

Technical Field

[0001] The invention relates to the field of flue gas heat exchangers, in particular to a heat exchange tube used in a MGGH flue gas heat exchanger device. Background Art

[0002] MGGH, or flue gas heat exchanger, is an important equipment used in flue gas treatment systems. MGGH flue gas heat exchanger mainly realizes heat transfer by circulating heat medium water between the flue gas cooler and the flue gas reheater. In the flue gas cooling section, the heat medium water absorbs the heat in the flue gas and heats up. In the flue gas reheating section, the heated heat medium water transfers the heat to the low-temperature flue gas to increase the flue gas temperature. The heat exchange tubes in the flue gas heat exchanger are usually installed in the shell of the heat exchanger. The flue gas flows in the tube, while the heat medium water or other heat exchange medium flows outside the tube. The tube wall of the heat exchange tube separates the flue gas and the heat medium water. The heat is transferred from the high-temperature side to the low-temperature side through the tube wall, so that heat exchange can be achieved through heat transfer of the tube wall.

[0003] Traditional heat exchange tubes are usually simple straight tube structures, and the flue gas usually flows in a straight line. This flow pattern causes the flue gas to stay in the tube for a short time, and the contact with the tube wall is not sufficient. The flow velocity near the tube wall is relatively low, while the flow velocity in the center area is higher, which leads to poor heat utilization effect. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a heat exchange tube for a MGGH flue gas heat exchanger device, which solves the problems raised in the above background technology.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solutions: A heat exchange tube for an MGGH flue gas heat exchanger device, comprising a tube body, a fixing member for ventilation is fixedly installed on the inner wall of the tube body, and a sliding member for ventilation is slidably installed, a telescopic mechanism for air intake is installed between the fixing member and the sliding member, a guide plate for elongation is installed between the tube body and the telescopic mechanism, an end of the guide plate close to the fixing member is fixedly connected to the inner wall of the tube body and the outer side of the telescopic mechanism, and the other end is fixedly connected to the sliding member;

[0006] A straight rod is fixedly connected to the inside of the sliding part, one end of the straight rod is located inside the telescopic mechanism, the end of the straight rod close to the fixed part is set as a hollow structure, an exhaust groove is opened on its outer surface, a sealing mechanism for sealing the exhaust groove is fixedly installed on the inner wall of the telescopic mechanism, and a pressure relief mechanism for exhaust is installed on the end of the straight rod close to the fixed part.

[0007] Preferably, the sliding member comprises a circular ring and a plurality of balls arranged in a circle, the plurality of balls are rotatably connected to the circular ring and are in contact with the inner wall of the tube body, and a plurality of vents A are provided inside the circular ring.

[0008] Preferably, an annular gap is left between the outer ring of the circular ring and the inner wall of the tube body.

[0009] Preferably, the end of the fixing member close to the telescopic mechanism is cylindrical, and the end of the fixing member close to the air inlet end of the tube body is hemispherical.

[0010] Preferably, the guide plate includes a spiral bimetallic strip, a buffer pad and an elastic scraper blade, the buffer pad is located between the bimetallic strip and the scraper blade, the outer ring of the buffer pad is fixedly connected to the inner ring of the scraper blade, and the inner ring is fixedly connected to the outer ring of the bimetallic strip, the bimetallic strip includes an active layer and a passive layer, and the active layer and the passive layer are firmly combined by welding.

[0011] Preferably, the sealing mechanism includes a sealing sleeve and a bracket, the outer side of the bracket is fixedly connected to the inner wall of the tube body, the inner wall of the bracket is fixedly connected to the outer surface of the sealing sleeve, and the inner wall of the sealing sleeve is in close contact with the outer surface of the straight rod.

[0012] Preferably, the telescopic mechanism includes an inner cylinder and an outer cylinder, the inner cylinder is slidably connected to the outer cylinder and fixedly connected to the sliding member, the end of the outer cylinder close to the fixing member is set as a conical structure, and the conical end of the outer cylinder is provided with an air inlet A, and the conical end of the outer cylinder is fixedly embedded with the fixing member.

[0013] Preferably, the pressure relief mechanism includes a sleeve, a spring, a fixed ring and a hollow conical head. The sleeve is slidably connected to the straight rod, the two ends of the spring are fixedly connected to the fixed ring and the conical head respectively, the outer ring of the fixed ring is fixedly connected to the inner wall of the outer tube, the conical head is tightly fitted to the conical end of the outer tube, the conical end of the conical head is provided with an air inlet B, the conical head and the fixed ring are both provided with exhaust ports, and the conical head is connected to the sleeve.

[0014] Preferably, the number of the air inlets B and the number of the air inlets A are both several, and the air inlets B and the air inlets A are staggered.

[0015] Preferably, the tube body, the straight rod, the fixing piece, the telescopic mechanism and the conical head are located at the same axis.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The heat exchange tube for the MGGH flue gas heat exchanger device has a spiral guide plate. The spiral structure of the guide plate can guide the flue gas. The flue gas stays in the tube body for a long time and the flow rate increases, so that the tube wall of the tube body and the flue gas can fully contact with each other, thereby improving the heat utilization efficiency. The conical head fits tightly with the conical end of the outer tube, and a closed state is formed between the conical head and the outer tube, so that a large amount of flue gas is located in the area of ​​the guide plate, and the cross section of this area is smaller than the cross section of the air inlet end of the tube body. When the flue gas flow rate is constant, the guide plate can guide the flue gas to the outside of the tube body. The flow velocity in the flow sheet area will increase. As the flow velocity of the flue gas increases, the centrifugal force and kinetic energy generated by the flue gas will increase, thereby increasing the friction between the flue gas and the inner wall of the tube body, causing the temperature of the tube body to rise again, further improving the utilization rate of the flue gas heat. When the flue gas contains more smoke particles, the chances of direct contact between the particles and the inner wall of the tube body and the guide vane increase. These particles will continuously collide and rub against the inner wall of the tube body and the surface of the guide vane during the flow process, thereby increasing the overall friction, thereby increasing the generated temperature and further improving the heat utilization rate.

[0018] 2. The heat exchange tube used for the MGGH flue gas heat exchanger device is composed of a bimetallic sheet, a buffer pad and a scraper through the guide plate provided. When flue gas containing a high concentration of smoke particles is passed into the tube body for a long time, the friction temperature between the smoke and the bimetallic sheet will increase significantly. The bimetallic sheet is composed of an active layer and a passive layer, so that the bimetallic sheet is bent and deformed and elongated. Due to the elongation of the guide plate, its pitch increases. After the pitch increases, the residence time of the smoke in the tube body is relatively reduced, so that the efficiency of smoke exhaust is improved and the probability of smoke damaging the tube body is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the pipe structure of the present invention;

[0020] Figure 2 A sectional view of a side view of a tube body of the present invention;

[0021] Figure 3 It is a schematic diagram of the telescopic mechanism structure of the present invention;

[0022] Figure 4 This is a schematic diagram of the guide plate structure of the present invention;

[0023] Figure 5 A partial cross-sectional view of the guide vane of the present invention;

[0024] Figure 6 It is a schematic diagram of the structure of the pressure relief mechanism of the present invention;

[0025] Figure 7 It is a schematic diagram of the structure of the fixing member of the present invention;

[0026] Figure 8It is a cross-sectional view of the top view of the tube body of the present invention;

[0027] Fig. 9 This is a schematic diagram of the straight rod structure of the present invention;

[0028] Fig.10 It is a schematic diagram of the sealing mechanism structure of the present invention.

[0029] Wherein: 1. tube body; 2. fixing part; 3. sliding part; 301. ring; 302. ball; 303. vent A; 4. telescopic mechanism; 401. inner tube; 402. outer tube; 5. guide vane; 501. bimetallic strip; 502. buffer pad; 503. scraper; 504. active layer; 505. passive layer; 6. straight rod; 7. exhaust groove; 8. sealing mechanism; 801. sealing sleeve; 802. bracket; 9. pressure relief mechanism; 901. sleeve; 902. spring; 903. fixing ring; 904. conical head; 11. air inlet A; 12. air inlet B. DETAILED DESCRIPTION

[0030] like Figure 1-Figure 10As shown, a heat exchange tube for an MGGH flue gas heat exchanger device includes a tube body 1, a fixing member 2 for ventilation is fixedly installed on the inner wall of the tube body 1, and a sliding member 3 for ventilation is slidably installed, the sliding member 3 includes a ring 301 and a plurality of balls 302 arranged in a circle, the plurality of balls 302 are rotatably connected to the ring 301, and are in contact with the inner wall of the tube body 1, a plurality of vents A303 are opened inside the ring 301, the balls 302 can reduce the resistance of the sliding member 3 when moving along the inner wall of the tube body 1, the vent A303 is used to discharge the flue gas inside the telescopic mechanism 4, the outer ring of the ring 301 is in contact with the tube body 1, and the outer ring of the ring 301 is in contact with the inner wall of the tube body 1. An annular gap is left between the inner walls of the tube body 1 for exhausting the smoke outside the telescopic mechanism 4. A telescopic mechanism 4 for air intake is installed between the fixed member 2 and the sliding member 3. The position of the fixed member 2 is fixed. The sliding member 3 moves along the inner wall of the tube body 1 through the telescopic mechanism 4. The position of the fixed member 2 is close to the air intake end of the tube body 1. The end of the fixed member 2 close to the telescopic mechanism 4 is cylindrical, and the end close to the air intake end of the tube body 1 is hemispherical. When the smoke enters the tube body 1 from the air intake end of the tube body 1, it is beneficial for the smoke to be transported along the outer side of the fixed member 2 to the telescopic mechanism 4. The telescopic mechanism 4 includes an inner cylinder 401 and an outer cylinder 402. The inner cylinder 4 01 is slidably connected to the outer cylinder 402 and fixedly connected to the sliding member 3. The end of the outer cylinder 402 close to the fixing member 2 is set to a conical structure, and the conical end of the outer cylinder 402 is provided with an air inlet A11. The conical end of the outer cylinder 402 is fixedly embedded with the fixing member 2. A guide plate 5 for elongation is installed between the tube body 1 and the telescopic mechanism 4. The guide plate 5 includes a spiral bimetallic strip 501, a buffer pad 502 and an elastic scraper 503. The buffer pad 502 is located between the bimetallic strip 501 and the scraper 503. The outer ring of the buffer pad 502 is fixedly connected to the inner ring of the scraper 503, and the inner ring is fixedly connected to the outer ring of the bimetallic strip 501. The bimetallic strip 501 is fixedly connected with the pipe body 1 by a circle, the bimetallic strip 501 includes an active layer 504 and a passive layer 505, the active layer 504 is made of copper material, the passive layer 505 is made of iron material, the active layer 504 and the passive layer 505 are firmly combined by welding, the bimetallic strip 501 is used to deform and elongate when heated, the buffer pad 502 is set to a high temperature resistant material, and is used to buffer the scraper 503 and the bimetallic strip 501, the scraper 503 is used to scrape off part of the dirt remaining on the inner wall of the pipe body 1, the end of the guide plate 5 close to the fixing member 2 is fixedly connected to the inner wall of the pipe body 1 and the outer side of the telescopic mechanism 4, and the other end is fixedly connected to the sliding member 3;

[0031] The interior of the sliding member 3 is fixedly connected with a straight rod 6, one end of the straight rod 6 is located inside the telescopic mechanism 4, and the end of the straight rod 6 close to the fixed member 2 is set as a hollow structure, and an exhaust groove 7 is opened on its outer surface. The number of exhaust grooves 7 is set in a plurality and arranged in a circumference. The inner wall of the telescopic mechanism 4 is fixedly installed with a sealing mechanism 8 for sealing the exhaust groove 7. The sealing mechanism 8 includes a sealing sleeve 801 and a bracket 802. The outer side of the bracket 802 is fixedly connected to the inner wall of the tube body 1, and the inner wall of the bracket 802 is connected to the sealing sleeve 801. The outer surface of the sleeve 801 is fixedly connected, and the inner wall of the sealing sleeve 801 is in close contact with the outer surface of the straight rod 6. Two brackets 802 are provided to fix the two ends of the sealing sleeve 801. The purpose of limiting the exhaust volume of the exhaust groove 7 is achieved through the sealing sleeve 801. A pressure relief mechanism 9 for exhaust is installed at one end of the straight rod 6 close to the fixing member 2. The pressure relief mechanism 9 includes a sleeve 901, a spring 902, a fixing ring 903 and a hollow conical head 904. The outer surface of the outer cylinder 402 is set to a smooth surface. The sleeve 901 and The straight rod 6 is slidably connected, and the two ends of the spring 902 are fixedly connected to the fixing ring 903 and the conical head 904 respectively. The outer ring of the fixing ring 903 is fixedly connected to the inner wall of the outer tube 402. The conical head 904 is tightly fitted with the conical end of the outer tube 402. The conical end of the conical head 904 is provided with an air inlet B12. The conical head 904 and the fixing ring 903 are both provided with exhaust ports. The conical head 904 is connected with the sleeve 901. The spring 902 is in a static state. When the gas pressure at the air inlet end of the tube body 1 exceeds a predetermined value, the conical head 904 is in a state of being ... value, the conical head 904 is disengaged from the conical end of the outer tube 402, allowing part of the smoke to be discharged, thereby relieving the pressure and preventing damage to the tube body 1 caused by excessive air pressure. When the air pressure is lower than the predetermined value, the number of air inlets B12 and air inlet A11 are both set to a plurality, and the air inlets B12 and air inlet A11 are staggered. Multiple air inlets B12 and air inlet A11 are set to increase the exhaust volume. The tube body 1, the straight rod 6, the fixing part 2, the telescopic mechanism 4 and the conical head 904 are at the same axis.

[0032] Working principle:

[0033] The tube body 1 is installed in the shell of the heat exchanger. The flue gas enters from the air inlet end of the tube body 1 and is discharged from the exhaust end of the tube body 1. The flue gas flows in the tube body 1, and the water in the shell flows in the tube. The tube wall of the heat exchange tube separates the flue gas and the heat medium water. When the flue gas enters the tube body 1, it first contacts the fixing member 2. One end of the fixing member 2 is hemispherical, so that the flue gas can move along the spherical surface of the fixing member 2 to the conical end of the outer cylinder 402, and spread evenly around along the conical surface. Then the flue gas reaches the guide vane 5. Since the guide vane 5 is spiral The spiral guide vane 5 has a specific spiral shape and inclination angle, which provides a spiral channel for the smoke. When the smoke enters the area with the spiral guide vane 5, the spiral structure of the guide vane 5 will guide the smoke, causing the smoke to flow along the spiral trajectory of the guide vane 5. Just like in a spiral slide, the movement trajectory of a person will be guided by the spiral structure of the slide, and the smoke will also move along the spiral shape of the spiral guide vane 5. When the smoke first contacts the spiral guide vane 5, due to its certain initial speed and kinetic energy, the smoke will generate centrifugal force under the guidance of the spiral guide vane 5. The centrifugal force causes the smoke to be continuously thrown outward during the movement along the spiral path, so that it can better fit the shape of the guide vane 5 for spiral movement, and the inertia of the smoke itself makes it tend to maintain the original movement direction and state after entering the area of ​​the spiral guide vane 5. Under the restriction of the guide vane 5, this inertia prompts the smoke to form a high-speed rotating vortex in the tube body 1. Under the action of the centrifugal force, the air pressure of the outer layer is higher due to the higher pressure. and kinetic energy, as well as the friction with the inner wall of the tube body 1, so that the temperature of the tube body 1 increases, and the heat is transferred from the high-temperature side to the low-temperature side through the tube wall of the tube body 1, that is, the water in the shell is heated by the heat transfer of the tube wall of the tube body 1. Due to the action of the spiral guide plate 5, the smoke stays in the tube body 1 for a long time and the flow rate increases, so that the tube wall of the tube body 1 can fully contact with the smoke, thereby improving the heat utilization efficiency. Finally, the smoke will pass through the annular gap between the outer ring 301 and the inner wall of the tube body 1, and be discharged from the exhaust end of the tube body 1.

[0034] Next, due to the staggered arrangement of the air inlet A11 and the air inlet, when the air pressure at the air inlet end of the tube body 1 is lower than the preset value, the conical head 904 fits tightly with the conical end of the outer tube 402, and a closed state is formed between the conical head 904 and the outer tube 402. The telescopic mechanism 4 isolates the smoke on its outside, and the tube body 1 controls the smoke on its inside, so that a large amount of smoke is located in the area between the outside of the telescopic mechanism 4 and the inside of the tube body 1, that is, the area of ​​the guide vane 5, and the cross-section of this area is smaller than the cross-section of the air inlet end of the tube body 1. When the smoke flow rate is constant, the flow velocity in the area of ​​the guide vane 5 will increase. As the flow velocity of the smoke increases, the centrifugal force and kinetic energy generated by the smoke increase, thereby increasing the friction between the smoke and the inner wall of the tube body 1, causing the temperature of the tube body 1 to rise again, further improving the utilization rate of the smoke heat.

[0035] Next, when the air pressure at the air inlet end of the tube body 1 exceeds a preset value, the smoke at the air inlet A11 will push the conical head 904 and overcome the reaction force of the spring 902, causing the conical head 904 to move away from the fixing member 2. When the conical head 904 loses contact with the conical end of the outer tube 402, a non-enclosed space is formed between the conical head 904 and the outer tube 402, allowing the smoke to pass through the air inlet B12 and enter the conical head 904. A portion of the smoke in the conical head 904 enters the straight rod 6, and another portion of the smoke enters the telescopic mechanism 4 through the exhaust ports in the conical head 904 and the fixing ring 903, and is discharged from the vent A303 along the inside of the telescopic mechanism 4 to the exhaust end of the tube body 1, thereby achieving the purpose of reducing the pressure and preventing damage to the tube body 1 caused by excessive air pressure.

[0036] Next, since the smoke contains smoke particles, when these smoke particles rotate at high speed, when the number of particles in the smoke increases, the chances of direct contact between the particles and the inner wall of the tube body 1 and the guide vane 5 increase. These particles will continuously collide and rub against the inner wall of the tube body 1 and the surface of the guide vane 5 during the flow process, thereby increasing the overall friction force, thereby increasing the generated temperature and further improving the heat utilization rate. It should be noted that when smoke containing a high concentration of smoke particles is passed into the tube body 1 for a long time, the smoke can heat the water in the shell to a predetermined temperature in a relatively short time. At this time, there is no need to increase the residence time of the smoke in the guide vane 5 area. Therefore, the guide vane 5 is composed of a bimetallic strip 501, a buffer pad 502 and a scraper 503. When smoke containing a high concentration of smoke particles is passed into the pipe body 1 for a long time, the friction temperature between the smoke and the bimetallic strip 501 will increase significantly. The bimetallic strip 501 is composed of an active layer 504 and a passive layer 505. The active layer 504 and the passive layer 505 are made of copper and iron respectively. The expansion coefficient of the copper material is greater than the expansion coefficient of the iron material, which causes the bimetallic strip 501 to bend and deform. The bimetallic strip 501 is spiral. This bending deformation causes the bimetallic strip 501 to stretch under the action of the spiral structure. Because the spiral structure makes the deformation of the guide plate 5 in all directions have a certain directionality, when it expands due to heat, it will stretch along the axial direction of the spiral. When the bimetallic strip 501 is stretched, it will drive the buffer The pad 502 and the elastic scraper 503 are stretched, so that the guide plate 5 is stretched as a whole. In this process, the inner diameters of the bimetallic strip 501 and the scraper 503 are usually reduced, and the bimetallic strip 501 will expand. The buffer pad 502 plays a buffering role to prevent the scraper 503 and the bimetallic strip 501 from being overly squeezed. Due to the stretching action of the guide plate 5, its pitch increases. After the pitch increases, the residence time of the smoke in the tube body 1 is relatively reduced, so that the efficiency of smoke exhaust is improved; because one end of the guide plate 5 is fixed to the tube body 1 and the outer cylinder 402, when the guide plate 5 is stretched, the position of one end of the guide plate 5 remains unchanged, and the other end drives the sliding member 3 to move away from the fixing member 2, and the ball 302 is arranged, not only the ring 3 can be made 01 and the tube body 1 leave an annular gap, which is also conducive to reducing the movement resistance of the ring 301. Then, the fixing part 2 drives the straight rod 6 to move, and the straight rod 6 drives the pressure relief mechanism 9 to move. When the pressure relief mechanism 9 moves, the conical head 904 in the pressure relief mechanism 9 is completely separated from the conical end of the outer cylinder 402, and the space between the two is increased, which is conducive to part of the flue gas entering the straight rod 6. When the straight rod 6 moves along the sealing sleeve 801, the exhaust groove 7 in the straight rod 6 will open. As the elongation of the bimetallic strip 501 increases, the moving distance of the sliding part 3 will also increase, thereby increasing the moving distance of the straight rod 6. Therefore, the greater the degree of opening of the exhaust groove 7, the greater the exhaust volume, thereby achieving the purpose of increasing the exhaust volume and reducing the probability of damage to the tube body 1 by the flue gas.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A heat exchange tube for a MGGH flue gas heat exchanger device, comprising a tube body (1), characterized in that: A fixing member (2) for ventilation is fixedly mounted on the inner wall of the tube body (1), and a sliding member (3) for ventilation is slidably mounted thereon; a telescopic mechanism (4) for air intake is mounted between the fixing member (2) and the sliding member (3); a guide plate (5) for elongation is mounted between the tube body (1) and the telescopic mechanism (4); an end of the guide plate (5) close to the fixing member (2) is fixedly connected to the inner wall of the tube body (1) and the outer side of the telescopic mechanism (4), and the other end is fixedly connected to the sliding member (3); A straight rod (6) is fixedly connected inside the sliding member (3), one end of the straight rod (6) is located inside the telescopic mechanism (4), the end of the straight rod (6) close to the fixed member (2) is arranged as a hollow structure, an exhaust groove (7) is provided on the outer surface of the straight rod (6), a sealing mechanism (8) for sealing the exhaust groove (7) is fixedly installed on the inner wall of the telescopic mechanism (4), and a pressure relief mechanism (9) for exhausting air is installed on the end of the straight rod (6) close to the fixed member (2).

2. The heat exchange tube for the MGGH flue gas heat exchanger device according to claim 1, characterized in that: The sliding member (3) comprises a circular ring (301) and a plurality of balls (302) arranged in a circle. The plurality of balls (302) are rotatably connected to the circular ring (301) and are in contact with the inner wall of the tube body (1). A plurality of vents A (303) are provided inside the circular ring (301).

3. The heat exchange tube for the MGGH flue gas heat exchanger device according to claim 2, characterized in that: An annular gap is left between the outer ring of the circular ring (301) and the inner wall of the tube body (1).

4. The heat exchange tube for the MGGH flue gas heat exchanger device according to claim 1, characterized in that: The end of the fixing member (2) close to the telescopic mechanism (4) is cylindrical, and the end close to the air inlet end of the tube body (1) is hemispherical.

5. The heat exchange tube for MGGH flue gas heat exchanger device according to claim 1, characterized in that: The guide plate (5) comprises a spiral bimetallic sheet (501), a buffer pad (502) and an elastic scraper (503); the buffer pad (502) is located between the bimetallic sheet (501) and the scraper (503); the outer ring of the buffer pad (502) is fixedly connected to the inner ring of the scraper (503); the inner ring of the buffer pad (502) is fixedly connected to the outer ring of the bimetallic sheet (501); the bimetallic sheet (501) comprises an active layer (504) and a passive layer (505); the active layer (504) and the passive layer (505) are firmly combined by welding.

6. The heat exchange tube for MGGH flue gas heat exchanger device according to claim 1, characterized in that: The sealing mechanism (8) comprises a sealing sleeve (801) and a bracket (802); the outer side of the bracket (802) is fixedly connected to the inner wall of the tube body (1); the inner wall of the bracket (802) is fixedly connected to the outer surface of the sealing sleeve (801); and the inner wall of the sealing sleeve (801) is in close contact with the outer surface of the straight rod (6).

7. The heat exchange tube for MGGH flue gas heat exchanger device according to claim 1, characterized in that: The telescopic mechanism (4) comprises an inner cylinder (401) and an outer cylinder (402); the inner cylinder (401) is slidably connected to the outer cylinder (402) and fixedly connected to the sliding member (3); one end of the outer cylinder (402) close to the fixing member (2) is arranged as a conical structure; the conical end of the outer cylinder (402) is provided with an air inlet A (11); and the conical end of the outer cylinder (402) is fixedly embedded with the fixing member (2).

8. The heat exchange tube for the MGGH flue gas heat exchanger device according to claim 7, characterized in that: The pressure relief mechanism (9) comprises a sleeve (901), a spring (902), a fixing ring (903) and a hollow conical head (904); the sleeve (901) is slidably connected to the straight rod (6); the two ends of the spring (902) are fixedly connected to the fixing ring (903) and the conical head (904) respectively; the outer ring of the fixing ring (903) is fixedly connected to the inner wall of the outer cylinder (402); the conical head (904) is tightly fitted to the conical end of the outer cylinder (402); an air inlet B (12) is provided at the conical end of the conical head (904); exhaust ports are provided inside the conical head (904) and the fixing ring (903); and the conical head (904) is connected to the sleeve (901).

9. The heat exchange tube for the MGGH flue gas heat exchanger device according to claim 8, characterized in that: The number of the air inlets B (12) and the air inlet A (11) is multiple, and the air inlets B (12) and the air inlet A (11) are staggered.

10. The heat exchange tube for the MGGH flue gas heat exchanger device according to claim 8, characterized in that: The tube body (1), the straight rod (6), the fixing member (2), the telescopic mechanism (4) and the conical head (904) are located at the same axis.

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