An air preheater adaptive bimetallic sealing device

Abstract

The utility model discloses a kind of air preheater self-adapting bimetallic sealing devices, at least including self-compensating sealing sheet, fixed sealing sheet and counterweight block;Self-compensating sealing sheet includes working blade and the n plug-in ears distributed along the length direction of working blade bottom, and there is interval between two adjacent plug-in ears;Fixed sealing sheet top is equipped with the n plug-in hole distributed along length direction;Plug-in ear and plug-in hole one-to-one correspondence, the number of counterweight block is n-1 block;Plug-in ear is movably inserted in corresponding plug-in hole, the top of self-compensating sealing sheet is higher than fixed sealing sheet top, and the bottom of every two plug-in ears is equipped with a counterweight block, and two ends of counterweight block are respectively connected with two plug-in ears, and self-compensating sealing sheet can rotate relative to fixed sealing sheet;Fixed sealing sheet bottom is installed on the hot end radial baffle of air preheater rotor by bolt, and the top of self-compensating sealing sheet cooperates with hot end sector plate and forms sealing pair.The above-mentioned device can adaptively compensate the change of air leakage gap, and the structure is simple, and service life is long.

Description

Technical Field

[0001] This utility model relates to an adaptive bimetallic sealing device for an air preheater, belonging to the field of air preheater sealing devices. Background Technology

[0002] A rotary air preheater is a heat exchange device used in large coal-fired power plant boilers. It utilizes the heat from boiler flue gas to heat the air needed for combustion, thereby improving boiler efficiency. As the air preheater rotor transitions from a cold to a hot state, the temperature difference between the upper and lower end faces and the reduced rigidity of the steel due to heating cause a "mushroom-like" deformation. Traditional rigid sealing plates are fixed to the rotor diaphragms in sections with bolts. As the rotor diaphragms deform, the air leakage gap also changes. Based on the mechanism of the rotor's "mushroom-like" deformation, appropriate cold-state clearances are reserved in the axial and radial positions at the cold end. In the hot state, the dynamic and static fit clearances approach zero. Although the reserved clearance at the radial position at the hot end is very small in the cold state, a large triangular air leakage area will form in the hot state.

[0003] To reduce the area of ​​the aforementioned triangular air leakage zone and lower the air preheater leakage rate, two technical approaches are generally adopted in engineering: one is the sector plate automatic tracking system (LCS) equipped by the three major domestic main unit manufacturers (Dongfang Boiler, Harbin Boiler and Shanghai Boiler); the other is the flexible sealing technology that has been developed in recent years.

[0004] It's easy to understand that this actually reflects two sides of the same problem: the air preheater sealing issue is about the fit between the sealing plate and the sector plate. Both automatic sealing plate contact with the sector plate and automatic sector plate tracking of the sealing plate can reduce air leakage. However, both solutions have the following problems in engineering applications: due to harsh operating conditions (high temperature, dust, etc.), maintenance quality, management level, and other factors, most power plant LCS systems cannot be put into normal operation or have unsatisfactory operation. HOWDEN, a leading global supplier of rotary air preheaters, has not yet equipped its air preheaters with LCS, which also indicates that this technology needs further improvement. Traditional flexible sealing technology, on the other hand, has exposed problems such as rapid wear and unreliable structure, making it fundamentally unable to meet engineering requirements.

[0005] Traditional flexible seals generally feature a design with a rotating shaft and a spring. The shaft is prone to jamming and the spring is prone to failure, which are the main reasons why traditional flexible seal structures are unreliable. Utility Model Content

[0006] This utility model provides an adaptive bimetallic sealing device for air preheaters. Through a simple and ingenious physical structure design, it can adaptively compensate for changes in air leakage gaps. It does not require structures such as shafts and springs, thus fundamentally overcoming problems such as easy jamming of shafts and easy failure of springs. It has low modification costs and long service life.

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

[0008] An adaptive bimetallic sealing device for an air preheater, comprising at least a self-compensating sealing plate, a fixed sealing plate, and a counterweight;

[0009] The self-compensating sealing strip includes a working blade and n insertion ears distributed along the length of the bottom of the working blade, with a gap between adjacent insertion ears;

[0010] The top of the fixed sealing plate has n insertion holes distributed along the length direction;

[0011] The number of plug ears and plug holes are equal and correspond one-to-one. The number of counterweights is n-1, where n≥2. The plug ears are movably inserted into the corresponding plug holes. The top of the self-compensating sealing plate is higher than the top of the fixed sealing plate. A counterweight is provided at the bottom of every two adjacent plug ears. The two ends of the counterweight are connected to the two adjacent plug ears respectively and are not connected to the fixed sealing plate. The self-compensating sealing plate can rotate relative to the fixed sealing plate.

[0012] The bottom of the fixed sealing plate is bolted to the radial partition plate at the hot end of the air preheater rotor, and the top of the self-compensating sealing plate cooperates with the hot end sector plate to form a sealing pair.

[0013] The aforementioned plug-in ear is movably inserted into the corresponding plug-in hole, meaning that the plug-in ear and the plug-in hole are not fixedly connected, and the self-compensating sealing plate can rotate relative to the fixed sealing plate.

[0014] The aforementioned adaptive bimetallic sealing device for the air preheater can adaptively compensate for changes in the gap (the gap between the partition plate and the sector plate). When the top of the self-compensating sealing plate is not pressed by the sector plate, under the gravity of the counterweight, the bottom of the insertion ear and / or the counterweight moves and fits against the side of the fixed sealing plate. At this time, the self-compensating sealing plate does not rotate, and the height of the sealing device is at its maximum, i.e., it is in the state of maximum gap compensation. When the gap decreases, the top of the self-compensating sealing plate is pressed by the sector plate. When the pressing force of the sector plate is greater than the force of the counterweight, the self-compensating sealing plate rotates relative to the fixed sealing plate (according to...). Figure 1 The installation direction is counterclockwise rotation), the total height of the sealing device decreases to accommodate the smaller gap; when the gap increases, the squeezing force of the sector plate on the top of the self-compensating sealing plate decreases or even disappears; when the force of the counterweight is greater than the squeezing force of the sector plate, the self-compensating sealing plate rotates in the opposite direction relative to the fixed sealing plate under the action of the counterweight (according to...). Figure 1 (The installation direction is clockwise rotation), the total height of the sealing device increases to accommodate the increased gap, until the sealing device returns to its maximum height.

[0015] During operation, the top of the self-compensating sealing plate in the aforementioned air preheater adaptive bimetallic sealing device is always higher than the top of the fixed sealing plate. The rotatable angle of the self-compensating sealing plate is determined based on the gap changes that need to be compensated under actual operating conditions.

[0016] Existing spring and shaft structures are prone to failure, jamming, short service life, and high accident rate. This application presents an adaptive bimetallic seal device for air preheaters that eliminates the need for springs and shafts, achieving adaptive clearance compensation with a simple and ingenious structure.

[0017] Both the self-compensating sealing sheet and the fixed sealing sheet in this application are elongated strips. The length directions of the self-compensating sealing sheet and the fixed sealing sheet are consistent. For the sake of consistency, the direction on the plug ear and the plug hole that is consistent with the length direction of the self-compensating sealing sheet is defined as the length direction of the plug ear and the plug hole.

[0018] To facilitate preparation and assembly, all plug ears are identical in shape and size, with equal spacing between adjacent plug ears; the length of the plug hole is 1-2 mm longer than the length of the plug ear. This ensures both ease of assembly and stability in use.

[0019] For ease of assembly and use, as one preferred implementation, the plug ear is a “7” shaped structure formed by splicing horizontal and vertical plates. That is, the longitudinal section of the plug ear is “7” shaped, and the end of the horizontal plate is connected to the bottom of the working blade to form a step.

[0020] To reduce or avoid friction, the working blades are angled at 8–35° to the vertical plate. This allows for better flexible yielding and improves safety.

[0021] To improve the stability of the device in practical use, the horizontal plates of each connector are arranged in a coplanar plane, and the vertical plates of each connector are also arranged in a coplanar plane. This facilitates assembly and better ensures the stability of the device in practical use.

[0022] To facilitate fabrication and meet general operating requirements, the horizontal and vertical plates are of equal length. The width of the horizontal plate is 5-15mm greater than the thickness of the fixed sealing plate, and the thickness of the horizontal plate is 2-8mm less than the height of the insertion hole. This allows the self-compensating sealing plate to rotate around the bottom of the insertion hole as a fulcrum. Of course, other sizes can be set according to the gap range required for compensation under actual operating conditions.

[0023] In this application, the length direction of the self-compensating sealing sheet and the fixed sealing sheet are the same. For the sake of consistency, the direction on the horizontal plate, vertical plate and the insertion hole that is the same as the length direction of the self-compensating sealing sheet is defined as the length direction of the horizontal plate, vertical plate and the insertion hole.

[0024] As one specific implementation, the aforementioned self-compensating sealing sheet can be formed by welding the plug-in lug to the bottom of the working blade.

[0025] To further ensure structural strength and stability, as another preferred implementation, the working blade and the insertion ear are integrated into a single structure. That is, during manufacturing, the bottom of the self-compensating sealing plate can be cut into a comb-like shape, and then a bending device can be used to obtain an insertion ear with a similar figure-7 structure.

[0026] The aforementioned fixed sealing plate is vertically positioned, while the working blade is angled upwards, with an angle of 8–35° between the working blade and the fixed sealing plate. This angle refers to the angle when the counterweight is at its lowest position, i.e., when the top of the self-compensating sealing plate is not under pressure. When the top of the self-compensating sealing plate is compressed and rotated, the counterweight position rises, and the angle between the working blade and the fixed sealing plate increases.

[0027] To further improve the stability of the device, the two ends of the counterweight are welded to two insertion lugs. It should be noted that the counterweight is not connected to the fixed sealing plate; the height of the counterweight changes during the rotation of the self-compensating sealing plate.

[0028] The aforementioned counterweight has a cylindrical or square column structure.

[0029] Unless otherwise specified, all technologies described in this utility model are existing technologies.

[0030] This utility model of an adaptive bimetallic sealing device for air preheaters can adaptively compensate for changes in air leakage gaps, and it eliminates the need for structures such as rotating shafts and springs, fundamentally overcoming problems such as easy jamming of rotating shafts and easy failure of springs. The structure is simple, ingenious, and reasonable, with low modification costs and long service life. Attached Figure Description

[0031] Figure 1 This is a front view of the adaptive bimetallic sealing device for the air preheater of this utility model;

[0032] Figure 2 for Figure 1 The left view;

[0033] Figure 3 This is a perspective view of the adaptive bimetallic sealing device for the air preheater of this utility model;

[0034] Figure 4 This is an exploded view of the adaptive bimetallic sealing device for the air preheater of this utility model;

[0035] Figure 5 This is a model diagram of the adaptive bimetallic sealing device for the air preheater of this utility model;

[0036] In the figure, 1 is the self-compensating sealing plate, 11 is the working blade, 12 is the insertion ear, 121 is the horizontal plate, 122 is the vertical plate, 2 is the fixed sealing plate, 21 is the insertion hole, and 3 is the counterweight. Detailed Implementation

[0037] 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.

[0038] The orientations or positional relationships indicated by terms such as "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. 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 a limitation of this utility model.

[0039] Example 1

[0040] like Figure 1-5 As shown, an adaptive bimetallic sealing device for an air preheater includes a self-compensating sealing plate, a fixed sealing plate, and counterweights. The self-compensating sealing plate includes a working blade and 10 insertion ears distributed along the length of the bottom of the working blade, with a gap between adjacent insertion ears. The fixed sealing plate has 10 insertion holes distributed along its length at its top. The number of insertion ears and insertion holes are equal and correspond one-to-one. There are 9 counterweights. The insertion ears are movably inserted into the corresponding insertion holes. The top of the self-compensating sealing plate is higher than the top of the fixed sealing plate. A counterweight is provided at the bottom of every two insertion ears. The two ends of the counterweight are connected to the two insertion ears respectively and are not connected to the fixed sealing plate. The self-compensating sealing plate can rotate relative to the fixed sealing plate.

[0041] The bottom of the fixed sealing plate is bolted to the radial partition plate at the hot end of the air preheater rotor, and the top of the self-compensating sealing plate cooperates with the hot end sector plate to form a sealing pair; the end-to-end adaptive bimetallic sealing device of the air preheater is installed on the radial partition plate at the hot end of the air preheater rotor to form a complete seal.

[0042] The aforementioned adaptive bimetallic sealing device for the air preheater can adaptively compensate for changes in the gap (the gap between the partition plate and the sector plate). When the top of the self-compensating sealing plate is not pressed by the sector plate, under the gravity of the counterweight, the bottom of the insertion ear and / or the counterweight moves and fits against the side of the fixed sealing plate. At this time, the self-compensating sealing plate does not rotate, and the height of the sealing device is at its maximum, i.e., it is in the state of maximum gap compensation. When the gap decreases, the top of the self-compensating sealing plate is pressed by the sector plate. When the pressing force of the sector plate is greater than the force of the counterweight, the self-compensating sealing plate rotates relative to the fixed sealing plate (according to...). Figure 1The installation direction is counterclockwise rotation), the total height of the sealing device decreases to accommodate the smaller gap; when the gap increases, the squeezing force of the sector plate on the top of the self-compensating sealing plate decreases or even disappears; when the force of the counterweight is greater than the squeezing force of the sector plate, the self-compensating sealing plate rotates in the opposite direction relative to the fixed sealing plate under the action of the counterweight (according to...). Figure 1 (The installation direction is clockwise rotation), the total height of the sealing device increases to accommodate the increased gap, until the sealing device returns to its maximum height. During use, the top of the self-compensating sealing plate in the aforementioned air preheater adaptive bimetallic sealing device is always higher than the top of the fixed sealing plate.

[0043] The aforementioned adaptive bimetallic sealing device for air preheaters can achieve adaptive compensation of gaps without the need for springs or shaft structures, and its structure is simple and ingenious.

[0044] Example 2

[0045] Based on Example 1, the following improvements were made: To facilitate preparation and assembly, all plug ears are identical in shape and size, and the spacing between adjacent plug ears is equal; the length of the plug hole is 1.5 mm longer than the length of the plug ear. This ensures both ease of assembly and stability in use.

[0046] Example 3

[0047] Based on Example 2, the following improvements were made: Figure 1 As shown, for ease of assembly and use, the plug ear is a “7” shaped structure formed by splicing horizontal and vertical plates. That is, the longitudinal section of the plug ear is “7” shaped, and the end of the horizontal plate is connected to the bottom of the working blade to form a step.

[0048] Example 4

[0049] Based on Example 3, the following improvements were further made: Figure 1 As shown, to improve the practical stability of the device, the horizontal plates of each connector are arranged in a coplanar plane, and the vertical plates of each connector are also arranged in a coplanar plane. This facilitates assembly and better ensures the practical stability of the device. To reduce or avoid friction, the working blades are at a 25° angle to the vertical plates. This allows for better flexible yielding and improves safety.

[0050] Example 5

[0051] Based on Example 4, the following improvements were made: Figure 1As shown, the fixed sealing plate is vertically positioned, the working blade is angled upwards, the counterweight is cylindrical, and the angle between the working blade and the fixed sealing plate is 25°. This angle refers to the angle when the counterweight is at its lowest position, i.e., when the top of the self-compensating sealing plate is not compressed. When the top of the self-compensating sealing plate is compressed and rotated, the counterweight position rises, and the angle between the working blade and the fixed sealing plate increases.

[0052] Example 6

[0053] Based on Example 5, the following improvements were made: the above-mentioned self-compensating sealing sheet is formed by welding the plug lug to the bottom of the working blade.

[0054] Example 7

[0055] Based on Example 5, the following improvements were made: To further ensure structural strength and stability, the working blade and the insertion ear are integrated into one structure. During fabrication, the bottom of the self-compensating sealing sheet can be formed into a comb-like shape by cutting or other methods, and then a bending device can be used to obtain an insertion ear with a similar figure-7 structure.

[0056] Example 8

[0057] Based on embodiment 6 or 7, the following improvements were made: In order to further improve the stability of the device, the two ends of the counterweight are welded to the two plug-in lugs respectively, but the counterweight is not connected to the fixed sealing plate. During the rotation of the self-compensating sealing plate, the height of the counterweight changes.

[0058] In this example, the self-compensating seal, the fixed seal, and the counterweight are all made of 304 stainless steel. The self-compensating seal is 2mm thick, the fixed seal is 3mm thick, the horizontal and vertical plates are of equal length, the width of the horizontal plate is 10mm greater than the thickness of the fixed seal, and the thickness of the horizontal plate is 3mm less than the height of the insertion hole. Of course, other sizes can be set according to the gap range required for compensation under actual working conditions. Note: The direction on the horizontal, vertical, and insertion holes that is consistent with the length direction of the self-compensating seal is defined as the length direction of the horizontal, vertical, and insertion holes.

[0059] Taking a 600MW unit as an example, under the conditions of 3.5% sulfur content and 28% ash content of coal, with a 70% load variation, the hot end air leakage rate is less than 2.5%. After 18 months of stable operation, no accidents caused by the sealing device have occurred. After shutdown and maintenance, the adaptive bimetallic sealing device of the air preheater can still be used.

[0060] The adaptive bimetallic sealing devices for air preheaters described above can adaptively compensate for changes in air leakage gaps, and do not require structures such as shafts or springs. This fundamentally overcomes problems such as easy jamming of shafts and easy failure of springs. The structure is simple, ingenious, and reasonable, with low modification costs and long service life.

Claims

1. An adaptive bimetallic sealing device for an air preheater, characterized in that: It includes at least a self-compensating sealing sheet (1), a fixed sealing sheet (2), and a counterweight (3); The self-compensating sealing plate (1) includes a working blade (11) and n plug ears (12) distributed along the length of the bottom of the working blade (11), with a gap between adjacent plug ears (12); The top of the fixed sealing (2) plate is provided with n insertion holes (21) distributed along the length direction; The number of plug ears (12) and plug holes (21) are equal and correspond one-to-one. The number of counterweights (3) is n-1, n≥2. The plug ears (12) are movably inserted into the corresponding plug holes (21). The top of the self-compensating sealing plate (1) is higher than the top of the fixed sealing plate (2). A counterweight (3) is provided at the bottom of every two adjacent plug ears (12). The two ends of the counterweight (3) are connected to the two plug ears (12) respectively and are not connected to the fixed sealing plate (2). The self-compensating sealing plate (1) can rotate relative to the fixed sealing plate (2). The bottom of the fixed sealing (2) plate is bolted to the radial partition plate at the hot end of the air preheater rotor, and the top of the self-compensating sealing (1) plate cooperates with the hot end sector plate to form a sealing pair.

2. The adaptive bimetallic seal device for air preheater according to claim 1, characterized in that: Each plug ear (12) has the same shape and size, and the interval between two adjacent plug ears (12) is equal; the length of the plug hole (21) is 1-2 mm longer than the length of the plug ear (12).

3. The adaptive bimetallic seal device for an air preheater according to claim 1 or 2, characterized in that: The plug-in ear (12) is a "7" shaped structure formed by splicing a horizontal plate (121) and a vertical plate (122), with the end of the horizontal plate (121) connected to the bottom of the working blade (11).

4. The adaptive bimetallic seal device for air preheater according to claim 3, characterized in that: The working blade (11) and the vertical plate (122) form an angle of 8 to 35 degrees.

5. The adaptive bimetallic seal device for air preheater according to claim 3, characterized in that: The horizontal plates (121) of each plug ear (12) are arranged in the same plane, and the vertical plates (122) of each plug ear (12) are arranged in the same plane.

6. The adaptive bimetallic seal device for an air preheater according to claim 3, characterized in that: The horizontal plate (121) and the vertical plate (122) are of equal length. The width of the horizontal plate (121) is 5-15mm larger than the thickness of the fixed sealing (2) plate. The thickness of the horizontal plate (121) is 2-8mm smaller than the height of the insertion hole (21).

7. The adaptive bimetallic seal device for an air preheater according to claim 1 or 2, characterized in that: The working blade (11) and the plug ear (12) are an integral structure.

8. The adaptive bimetallic seal device for an air preheater according to claim 1 or 2, characterized in that: The fixed sealing (2) plate is set vertically, and the working blade (11) is set obliquely upward. The included angle between the working blade (11) and the fixed sealing (2) plate is 8 to 35°.

9. The adaptive bimetallic seal device for an air preheater according to claim 1 or 2, characterized in that: The two ends of the counterweight (3) are welded to the two plug-in lugs (12) respectively.

10. The adaptive bimetallic seal device for an air preheater according to claim 1 or 2, characterized in that: The counterweight (3) has a cylindrical or square column structure.

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