Simple up and down self-adapting air preheater cold end gravity type sealing device

Abstract

The utility model discloses a simple and easy up and down self -adaptation type air preheater cold end gravity type sealing device, install on the cold end radial baffle, including arc sealing plate, fixed distance pipe, fixed distance presser, bolt and nut, arc sealing plate is composed of the flat structure and arc plate structure of upper and lower joint, is equipped with vertical waist type hole on the flat structure, the length of fixed distance pipe is greater than the thickness of flat structure on arc sealing plate, and fixed distance pipe is inserted in the inboard of vertical waist type hole on arc sealing plate, and is equipped with mounting hole on cold end radial baffle and fixed distance presser, the hole diameter of mounting hole on cold end radial baffle and fixed distance presser is all less than the outer diameter of fixed distance pipe, and bolt passes through the mounting hole on fixed distance presser, fixed distance pipe and the mounting hole on baffle in proper order and is fixed with nut, and the both ends of fixed distance pipe are pressed in fixed distance presser and cold end radial baffle respectively, and the convex end part of arc plate structure on arc sealing plate forms sealing pair with cold end sector plate. The above -mentioned device is simple, stable, reliable, and has strong self -adaptability.

Description

Technical Field

[0001] This utility model belongs to the field of Junkers air preheater sealing, and relates to a simple upper and lower adaptive gravity sealing device for the cold end of an air preheater. Background Technology

[0002] A Junkers air preheater (hereinafter referred to as "air preheater") is a heat exchange device used in large power plant boilers. It utilizes the heat from the high-temperature flue gas in the boiler to heat the air required for boiler combustion. The rotor of the air preheater consists of a large number of heat storage elements. When the rotor rotates slowly, the flue gas and air flow alternately through the rotor in opposite directions. The heat storage elements absorb heat on the flue gas side and release heat on the air side, thereby reducing the boiler exhaust temperature, preheating the air required for boiler combustion, and thus improving the economic efficiency of the power plant.

[0003] The air preheater rotor is essentially a huge cylinder. As the rotor transitions from a cold to a hot state, the temperature difference between its upper and lower end faces, along with the reduced rigidity of the steel due to heating, causes a "mushroom-like" deformation. Therefore, during cold installation, a clearance must be maintained between the air preheater rotor and the stator. The size of this clearance depends on the deformation of each component of the air preheater, especially the rotor. In principle, it is essential to ensure that the rotor and stator do not rub against each other under any operating condition to prevent rotor jamming and potential safety accidents. In other words, the radial clearance at the cold end of the air preheater is determined based on the maximum rotor deformation under full boiler load conditions.

[0004] Because the air-side pressure in an air preheater is higher than the flue gas-side pressure, a sealing device is needed to reduce air leakage to the flue gas side, thereby minimizing energy loss. The conventional engineering practice is to install sealing plates on the rotor diaphragms, connecting them with bolts. The rotor diaphragms are typically long, with shorter sealing plates joined end-to-end to form a complete seal. Traditional sealing plates are straight, requiring a relatively large sealing gap during installation to ensure the safe and stable operation of the air preheater. The air leakage rate is a crucial indicator of the air preheater's leakage level. Over time, the air leakage rate of air preheaters using traditional rigid sealing plates has increased significantly.

[0005] As the amount of electricity connected to the grid from new energy sources gradually increases, coal-fired power generating units are operating at low loads for extended periods, resulting in low flue gas temperatures at the boiler tail end. Consequently, the "mushroom-shaped" deformation of the aforementioned air preheater is not fully achieved. If traditional rigid sealing sheets are used, the air preheater's cold end leaks significantly, impacting the economic efficiency of the boiler system. Utility Model Content

[0006] The purpose of this invention is to provide a simple, adaptive gravity sealing device for the cold end of an air preheater, which is applied to radial sealing of the cold end of an air preheater and can significantly reduce air leakage at the cold end of the air preheater under low-load boiler operation.

[0007] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0008] A simple, adaptive-type gravity sealing device for the cold end of an air preheater, installed on a radial partition at the cold end, includes at least an arc-shaped sealing plate, a spacer tube, a spacer pressure plate, bolts, and nuts;

[0009] The arc-shaped sealing plate consists of a flat plate structure and an arc-shaped plate structure connected at the top and bottom (that is, the upper part of the arc-shaped sealing plate is a flat plate and the lower part is an arc-shaped plate). The longitudinal section of the arc-shaped plate structure is an arc with a radius of 30-80mm. The flat plate structure is provided with vertical waist-shaped holes. The length of the spacer tube is greater than the thickness of the flat plate structure on the arc-shaped sealing plate. The spacer tube is movably inserted into the inner side of the vertical waist-shaped hole on the arc-shaped sealing plate. That is, the arc-shaped sealing plate can move relative to the spacer tube. The spacer tube is only movably inserted into the inner side of the vertical waist-shaped hole on the arc-shaped sealing plate. The two are not connected to each other.

[0010] Mounting holes are provided on both the cold-end radial partition and the spacer plate; the diameter of the mounting holes on both the cold-end radial partition and the spacer plate is smaller than the outer diameter of the spacer tube; after the bolt passes through the mounting holes on the spacer plate, the spacer tube and the partition in sequence, it is fixed with nuts; the two ends of the spacer tube are respectively pressed onto the spacer plate and the cold-end radial partition; the convex end of the arc-shaped plate structure on the arc-shaped sealing plate forms a sealing pair with the cold-end fan-shaped plate.

[0011] The aforementioned arc-shaped sealing plate has a concave surface (inner side) on one side and a convex surface (outer side) on the other side. One end of the arc-shaped plate structure is connected to the flat plate structure, and the other end forms a sealing pair with the cold-end fan-shaped plate.

[0012] The bottom of the arc-shaped sealing plate in this application adopts an arc-shaped plate structure with a radius of 30-80mm, which can precisely match the curved surface contour of the fan-shaped plate, forming a dynamic surface contact seal during rotor rotation. Compared with the existing straight plate and bent plate structures, not only is the sealing performance significantly improved, but the contact stress distribution between the sealing plate and the fan-shaped plate is also more uniform and the impact stress is smaller, reducing local wear, deformation and damage, significantly improving adaptability, reducing or avoiding accidents such as jamming and breakage, and extending service life.

[0013] This application presents a simple, adjustable gravity-type sealing device for the cold end of an air preheater. An arc-shaped sealing plate is fitted around a spacer tube through a vertical, oblong hole. The length of the spacer tube is greater than the thickness of the flat plate structure on the arc-shaped sealing plate. Both ends of the spacer tube are pressed against a spacer plate and a radial partition plate at the cold end, respectively. This allows the height of the arc-shaped sealing plate to automatically adjust according to the gap size, adaptively compensating for gap changes. When the gap widens, the arc-shaped sealing plate automatically lowers under gravity until it contacts the fan-shaped plate to compensate for the increased gap. When the gap narrows, the arc-shaped sealing plate automatically rises under the upward force of the fan-shaped plate to accommodate the smaller gap. The device features a simple, reliable, and highly adaptive structure, significantly reducing air leakage.

[0014] The present application describes a vertical oblong hole, in which the long side of the hole is aligned with the direction of gravity (or the vertical axis of the component).

[0015] The total vertical length of the vertical oblong hole in this application can be set to the maximum amount of gap required to supplement the gap according to the specific working conditions.

[0016] This application does not require the installation of electric actuators, hydraulic cylinders, pressure sensors, or other structures, resulting in low cost, simple structure, and ease of modification and promotion.

[0017] Existing automatic sealing tracking technology requires sensors to monitor the mushroom-shaped deformation of the rotor in real time and transmit the signal to the control system. The control system then adjusts the distance between the fan-shaped plate and the rotor in real time based on the signal to reduce the sealing gap and prevent air leakage to the flue gas side. Because the air preheater is located in a high-temperature, dusty environment, this can easily cause sensor failure and jamming of the mechanical actuators, resulting in a short service life. This application, however, effectively avoids these problems through a simple physical structure design, offering good adaptability, low cost, and long service life.

[0018] In this application, radial diaphragm, sector plate, rotor, etc. are all conventional component names of air preheater equipment.

[0019] To balance cost and sealing performance, as a preferred implementation, the arc length of the longitudinal section of the arc-shaped sealing plate is πr / 2, where r is the radius of the arc-shaped plate structure. In other words, the longitudinal section of the arc-shaped plate structure is a quarter circle.

[0020] To further improve sealing, the aforementioned simplified adaptive air preheater cold end gravity sealing device also includes a sealing baffle. The sealing baffle has mounting holes, the diameter of which is smaller than the outer diameter of the spacer tube. Bolts are passed sequentially through mounting holes on the spacer plate, the spacer tube, the sealing baffle, and the partition plate, and then secured with nuts. Both ends of the spacer tube are pressed onto the spacer plate and the sealing baffle, respectively, and the bottoms of both the spacer plate and the sealing baffle extend beyond the bottom of the vertical oblong hole on the arc-shaped sealing plate. This further ensures a tight seal.

[0021] To meet the sealing requirements of general operating conditions, the bottom of both the spacer plate and the sealing shield extends at least 3mm beyond the bottom of the vertical oblong hole on the arc-shaped sealing plate.

[0022] The aforementioned cold-end radial partition, spacer plate, and sealing baffle all have three or more mounting holes distributed along their length, while the arc-shaped sealing plate has three or more vertical oblong holes distributed along its length. The number of mounting holes on the cold-end radial partition, the spacer plate, the sealing baffle, and the vertical oblong holes on the arc-shaped sealing plate are equal and correspond one-to-one. Each vertical oblong hole contains a spacer tube, and each set of corresponding mounting holes contains a matching bolt and nut.

[0023] To further improve the structural strength of the device and extend its service life, a first reinforcing rib is provided on the concave side of the arc-shaped plate structure at the bottom of each vertical waist-shaped hole.

[0024] To better ensure the structural strength and service life of the gravity-sealed device at the cold end of the simplified adaptive air preheater, a second reinforcing rib is provided between two adjacent first reinforcing ribs on the concave side of the arc-shaped plate structure. Both the first and second reinforcing ribs are located at the bottom of the spaced pressure plate and do not affect installation.

[0025] In order to ensure the structural stability and adaptability of the gravity sealing device at the cold end of the simplified upper and lower adaptive air preheater, the length of the spacer tube is 0.5-2mm longer than the thickness of the flat plate structure area on the arc-shaped sealing plate.

[0026] To better ensure structural stability, the arc-shaped sealing plate is an integral structure, that is, the flat plate structure and the arc-shaped plate structure are integrated into one structure.

[0027] To meet the sealing requirements of general working conditions, the thickness of the arc-shaped sealing plate is 2.5 to 3.5 mm, and the material used for the arc-shaped sealing plate is 304 stainless steel.

[0028] To further extend the service life of the gravity-type sealing device at the cold end of the simplified adaptive air preheater, the convex surface of the arc-shaped sealing plate is coated with a ceramic coating. This significantly improves the wear resistance of the arc-shaped sealing plate and extends its service life.

[0029] To better suit high-dust environments and improve wear resistance, the ceramic coating is a WC-Co cermet coating with a thickness of 0.1-0.3 mm. The preparation of the WC-Co cermet coating can refer to the method in application number 2008101146666.4.

[0030] All technologies not mentioned in this utility model are existing technologies.

[0031] This utility model relates to a simplified, adaptive gravity-type sealing device for the cold end of an air preheater. The bottom of the arc-shaped sealing plate uses an arc-shaped plate structure with a radius of 30-80mm, forming a dynamic surface contact seal during rotor rotation. This significantly improves sealing performance and makes the contact stress distribution between the sealing plate and the fan-shaped plate more uniform, reducing impact stress and minimizing localized wear, deformation, and damage. This significantly enhances adaptability, reduces or avoids accidents such as jamming and breakage, and extends service life. Simultaneously, the arc-shaped sealing plate is fitted around the spacer tube through a vertical oblong hole. The length of the spacer tube is greater than the thickness of the flat plate structure on the arc-shaped sealing plate. Both ends of the spacer tube are pressed against the spacer pressure plate and the cold end radial partition, respectively. This allows the height of the arc-shaped sealing plate to automatically adjust according to the gap size, adaptively compensating for gap changes. When the gap increases, the arc-shaped sealing plate automatically lowers under gravity until it contacts the fan-shaped plate to compensate for the increased gap; when the gap decreases, the arc-shaped sealing plate automatically rises under the upward force of the fan-shaped plate to adapt to the smaller gap, significantly reducing the air leakage rate. It has a simple structure, stable and reliable operation, strong adaptability, no need for special sensing equipment, low cost, and long service life. It is suitable for both high-load and low-load operation of coal-fired power generation units. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the simplified upper and lower adaptive type air preheater cold end gravity sealing device of this utility model. Figure 1 ;

[0033] Figure 2 This is a schematic diagram of the structure of the simplified upper and lower adaptive type air preheater cold end gravity sealing device of this utility model. Figure 2 ;

[0034] Figure 3 for Figure 2 3D image

[0035] Figure 4 for Figure 2The left view;

[0036] Figure 5 for Figure 2 Exploded view;

[0037] Figure 6 for Figure 2 Model diagram;

[0038] Figure 7 This is a schematic diagram of the structure of the simplified upper and lower adaptive type air preheater cold end gravity sealing device of this utility model. Figure 3 ;

[0039] Figure 8 for Figure 7 3D image

[0040] Figure 9 for Figure 7 Exploded view;

[0041] Figure 10 for Figure 7 Model diagram;

[0042] In the figure, 1 is an arc-shaped sealing plate, 11 is a flat plate structure, 12 is an arc-shaped plate structure, 13 is a vertical waist-shaped hole, 14 is the first reinforcing rib, 15 is the second reinforcing rib, 2 is a spacer tube, 3 is a spacer pressure plate, 4 is a bolt, 5 is a nut, 6 is a sealing shield, and 7 is a cold end radial partition. Detailed Implementation

[0043] To better understand this utility model, the following embodiments further illustrate the content of this utility model, but the content of this utility model is not limited to the following embodiments.

[0044] The directional terms used in this application, such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," are based on the orientation or positional relationship shown in the accompanying drawings or in the usage state, and are only for the convenience of describing this application. They are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application.

[0045] Example 1

[0046] like Figure 1 As shown, a simple vertical adaptive air preheater cold end gravity sealing device is installed on the cold end radial partition and includes at least an arc-shaped sealing plate, a spacer tube, a spacer pressure plate, bolts and nuts;

[0047] The arc-shaped sealing plate consists of a flat plate structure and an arc-shaped plate structure connected at the top and bottom. The longitudinal section of the arc-shaped plate structure is an arc with a radius of 80mm. That is, the top of the arc-shaped sealing plate is a flat plate structure and the bottom is an arc-shaped plate structure with a radius of 80mm. The flat plate structure is provided with vertical waist-shaped holes. The length of the spacer tube is greater than the thickness of the flat plate structure on the arc-shaped sealing plate. The spacer tube is movably inserted into the inner side of the vertical waist-shaped hole on the arc-shaped sealing plate. That is, the arc-shaped sealing plate can move relative to the spacer tube. The spacer tube is only movably inserted into the inner side of the vertical waist-shaped hole on the arc-shaped sealing plate, and the two are not connected to each other.

[0048] Both the cold-end radial partition and the spacer plate are provided with mounting holes; the diameters of the mounting holes on the cold-end radial partition and the spacer plate are smaller than the outer diameter of the spacer tube; the bolts pass through the mounting holes on the spacer plate, the spacer tube, and the partition in sequence, and are then secured with nuts; both ends of the spacer tube are pressed onto the spacer plate and the cold-end radial partition respectively; the convex end of the arc-shaped sealing plate structure (i.e., as shown in the image) Figure 1 The bottom of the convex side of the arc-shaped plate structure shown forms a sealing pair with the cold end fan-shaped plate.

[0049] The aforementioned arc-shaped sealing plate, with an 80mm radius arc-shaped structure at its bottom, precisely matches the sealing surface contour of the sector plate, forming a dynamic surface contact seal during rotor rotation. Compared to existing straight and bent plate structures, this not only significantly improves sealing performance but also results in a more uniform stress distribution between the sealing plate and the sector plate, reducing impact stress and minimizing localized wear, deformation, and damage. This significantly enhances adaptability, reduces or eliminates accidents such as jamming and breakage, and extends service life.

[0050] The aforementioned arc-shaped sealing plate is fitted around the spacer tube through a vertical oblong hole. The length of the spacer tube is greater than the thickness of the flat plate structure on the arc-shaped sealing plate. Both ends of the spacer tube are pressed against the spacer pressure plate and the cold-end radial partition, respectively. This allows the height of the arc-shaped sealing plate to automatically adjust according to the gap size, adaptively compensating for gap changes. When the gap increases, the arc-shaped sealing plate automatically lowers under gravity until it contacts the fan-shaped plate to compensate for the increased gap; when the gap decreases, the arc-shaped sealing plate automatically rises under the upward force of the fan-shaped plate to adapt to the smaller gap. The structure is simple, reliable, highly adaptive, and significantly reduces the air leakage rate.

[0051] Example 2

[0052] Based on Example 1, the following improvements were made: the arc length of the longitudinal section of the arc-shaped plate structure on the arc-shaped sealing plate is πr / 2, where r is the radius of the arc-shaped plate structure. That is, the longitudinal section of the arc-shaped plate structure is 1 / 4 of a circle.

[0053] Example 3

[0054] Based on Example 2, the following improvements were made: Figure 7-10 As shown, to further improve sealing performance, the aforementioned simplified adaptive air preheater cold end gravity sealing device also includes a sealing baffle. The sealing baffle has mounting holes, the diameter of which is smaller than the outer diameter of the spacer tube. Bolts are passed sequentially through the mounting holes on the spacer plate, the spacer tube, the sealing baffle, and the partition plate, and then secured with nuts. Both ends of the spacer tube are pressed onto the spacer plate and the sealing baffle, respectively, with the bottom of both the spacer plate and the sealing baffle extending 4mm beyond the bottom of the vertical oblong hole on the arc-shaped sealing plate. This further ensures sealing performance. During use, the convex end of the arc-shaped plate structure on the arc-shaped sealing plate always extends beyond the spacer plate and the sealing baffle, meaning that the spacer plate and sealing baffle improve stability and sealing performance without affecting the sealing effect. The number of mounting holes on the cold end radial partition, the mounting holes on the spacer plate, the mounting holes on the sealing shield, and the vertical waist-shaped holes on the arc-shaped sealing plate are equal and correspond one-to-one. A spacer tube is installed in each vertical waist-shaped hole, and each set of corresponding mounting holes and spacer tubes is equipped with matching bolts and nuts.

[0055] Example 4

[0056] Based on Example 2 or 3, the following improvements were further made: Figure 2-10 As shown, in order to further improve the structural strength of the device and extend its service life, the concave side of the arc plate structure at the bottom of each vertical waist-shaped hole is provided with a first reinforcing rib.

[0057] Example 5

[0058] Based on Example 4, the following improvements were made: Figure 2-10 As shown, in order to better ensure the structural strength of the gravity sealing device at the cold end of the simplified adaptive air preheater and thus ensure its service life, a first reinforcing rib is provided on the concave side of the arc plate structure at the bottom of each vertical waist-shaped hole, and a second reinforcing rib is provided between each two adjacent first reinforcing ribs (the second reinforcing rib is provided on the concave side of the arc plate structure).

[0059] Example 6

[0060] Based on Example 5, the following improvements were made: the length of the spacer tube is 1.5 mm greater than the thickness of the flat plate structure area on the arc-shaped sealing plate.

[0061] Example 7

[0062] Based on Example 6, the following improvements were made: the arc-shaped sealing plate is an integral structure, and the arc-shaped sealing plate is made of 304 stainless steel with a thickness of 3mm.

[0063] Example 8

[0064] Based on Example 7, the following improvements were made: the convex surface of the arc-shaped sealing plate structure is coated with a WC-Co metal ceramic coating with a thickness of 0.2 mm.

[0065] Taking a 600MW unit as an example, under the conditions of 3.5% sulfur content and 28% ash content of coal, the cold end air leakage rate is less than 1.5% when the unit load changes from 30% to 100%. After 12 months of stable operation, the cold end air leakage rate hardly increases.

[0066] Comparative Example 1

[0067] The curved sealing plate was replaced with a straight or bent plate, while all other aspects remained the same as in Example 8. Compared to the straight and bent plates in this example, the peak stress of the curved sealing plate in Example 8 was reduced by more than 35%, the air leakage rate was reduced by more than 1.5%, and the service life was extended from 12 months to more than 24 months.

[0068] The simplified adaptive gravity-type sealing device for the cold end of the air preheater described above uses an arc-shaped plate structure at the bottom of the arc-shaped sealing plate. During rotor rotation, this creates a dynamic surface contact seal, significantly improving sealing performance and resulting in a more uniform stress distribution and lower impact stress between the sealing plate and the fan-shaped plate. This reduces localized wear, deformation, and damage, significantly enhancing adaptability, reducing or preventing accidents such as jamming and breakage, and extending service life. Simultaneously, the arc-shaped sealing plate is fitted around the spacer tube through a vertical oblong hole. The length of the spacer tube is greater than the thickness of the flat plate structure on the arc-shaped sealing plate, and both ends of the spacer tube are pressed against the spacer pressure plate and the cold end radial partition, respectively. This allows the height of the arc-shaped sealing plate to automatically adjust according to the gap size, adaptively compensating for gap changes. When the gap increases, the arc-shaped sealing plate automatically lowers under gravity until it contacts the fan-shaped plate to compensate for the increased gap; when the gap decreases, the arc-shaped sealing plate automatically rises under the upward action of the fan-shaped plate to adapt to the smaller gap, significantly reducing the air leakage rate. It has a simple structure, stable and reliable operation, strong adaptability, no need for special sensing equipment, low cost, and long service life. It is suitable for both high-load and low-load operation of coal-fired power generation units.

[0069] The above embodiments do not limit the present invention in any way. All technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A simple upper and lower adaptive air preheater cold end gravity sealing device, installed on the cold end radial baffle, characterized in that: It includes at least an arc-shaped sealing plate, a spacer tube, a spacer pressure plate, bolts, and nuts; The arc-shaped sealing plate consists of a flat plate structure and an arc-shaped plate structure connected at the top and bottom. The longitudinal section of the arc-shaped plate structure is a circular arc with a radius of 30-80mm. The flat plate structure is provided with vertical waist-shaped holes. The length of the spacer tube is greater than the thickness of the flat plate structure on the arc-shaped sealing plate. The spacer tube is movably inserted into the inside of the vertical waist-shaped holes on the arc-shaped sealing plate. Mounting holes are provided on both the cold-end radial partition and the spacer plate; the diameter of the mounting holes on both the cold-end radial partition and the spacer plate is smaller than the outer diameter of the spacer tube; after the bolt passes through the mounting holes on the spacer plate, the spacer tube and the partition in sequence, it is fixed with nuts; the two ends of the spacer tube are respectively pressed onto the spacer plate and the cold-end radial partition; the convex end of the arc-shaped plate structure on the arc-shaped sealing plate forms a sealing pair with the cold-end fan-shaped plate.

2. The simple top and bottom adaptive air preheater cold end gravity seal apparatus according to claim 1, characterized in that: The arc length of the longitudinal section of the arc-shaped plate structure on the arc-shaped sealing plate is πr / 2, where r is the radius of the arc-shaped plate structure.

3. The simple top and bottom adaptive air preheater cold end gravity seal as claimed in claim 1 or 2, characterized in that: It also includes a sealing shield, which has mounting holes. The diameter of the mounting holes on the sealing shield is smaller than the outer diameter of the spacer tube. After the bolt passes through the mounting holes on the spacer plate, the spacer tube, the mounting holes on the sealing shield, and the mounting holes on the partition in sequence, it is fixed with nuts. The two ends of the spacer tube are pressed onto the spacer plate and the sealing shield respectively, and the bottoms of the spacer plate and the sealing shield both extend beyond the bottom of the vertical waist-shaped hole on the arc-shaped sealing plate.

4. The simple top and bottom adaptive air preheater cold end gravity seal as claimed in claim 3, wherein: The bottom of the spacer plate and the bottom of the sealing shield both extend at least 3mm beyond the bottom of the vertical oblong hole on the arc-shaped sealing plate.

5. The simplified upper and lower adaptive type air preheater cold end gravity sealing device according to claim 1 or 2, characterized in that: Each vertical waist-shaped hole has a first reinforcing rib on the concave side of the arc-shaped plate structure at the bottom.

6. The simple top and bottom adaptive air preheater cold end gravity seal as claimed in claim 5, wherein: A second reinforcing rib is provided between two adjacent first reinforcing ribs on the concave side of the arc-shaped plate structure.

7. The simple top and bottom adaptive air preheater cold end gravity seal as claimed in claim 1 or 2, wherein: The length of the spacer tube is 0.5-2mm greater than the thickness of the flat plate structure on the arc-shaped sealing plate.

8. The simple top and bottom adaptive air preheater cold end gravity seal as claimed in claim 1 or 2, wherein: The arc-shaped sealing plate is an integral structure; the thickness of the arc-shaped sealing plate is 2.5-3.5mm, and the material used is 304 stainless steel.

9. The simple top and bottom adaptive air preheater cold end gravity seal as claimed in claim 1 or 2, wherein: The convex surface of the arc-shaped sealing plate structure is coated with a ceramic coating.

10. The simple top and bottom adaptive air preheater cold end gravity seal as claimed in claim 9, wherein: The ceramic coating is a WC-Co metal-ceramic coating with a thickness of 0.1-0.3 mm.

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