A radial arc sealing device for hot end of air preheater and its installation structure

Abstract

The present invention discloses a radial arc sealing device at the hot end of an air preheater and its mounting structure. The radial arc sealing device at the hot end of an air preheater comprises a sealing sheet, a fixed clamp, a first driving clamp, a second driving clamp and a wrapping sheet; the expansion coefficients of the sealing sheet, the fixed clamp and the wrapping sheet are smaller than the expansion coefficients of the first driving clamp and the second driving clamp; the sealing sheet and the wrapping sheet are arranged relative to each other, one end of the sealing sheet in the width direction exceeds the wrapping sheet to form a sealing end, and the sealing end of the sealing sheet is provided with a stress dividing seam starting from the top; the length of the first driving clamp is greater than the length of the second driving clamp; the fixed clamp, the first driving clamp and the second driving clamp are sequentially arranged between the sealing sheet and the wrapping sheet; the first driving clamp and the second driving clamp are welded by three-point welding. The radial arc sealing device at the hot end of an air preheater of the present invention can cooperate with the deformation characteristics of the bottom surface of the fan-shaped plate at the hot end of the air preheater in the hot state to bend downward, thereby reducing the air leakage gap and significantly reducing the air leakage rate of the air preheater.

Description

Technical Field

[0001] The invention relates to a radial arc sealing device at the hot end of an air preheater and a mounting structure thereof, which is suitable for an air preheater with a fixed sector plate at the hot end and belongs to the technical field of air preheater sealing. Background Art

[0002] Air preheater is a heat exchange device used in large coal-fired power plant boilers. It uses the heat of boiler flue gas to heat the air required for combustion, thereby improving the efficiency of the boiler. When the air preheater rotor changes from cold to hot, it will produce a "mushroom-shaped" deformation due to the different temperatures of the upper and lower end surfaces and the weakening of the rigidity of the steel after heating. HOWDEN, a leading global air preheater manufacturer, manufactures air preheater hot end fan plates with a fixed design. The traditional rigid sealing plate is fixed to the rotor partition by bolts in sections. As the rotor partition deforms, the air leakage gap also changes, forming a larger triangular air leakage area in the hot state.

[0003] For the air preheater with fixed fan-shaped plates, from cold state to hot state, since the temperature of the upper side (insulation side) of the hot end fan-shaped plate is lower than the temperature of the lower side (close to the rotor side), and the rigidity of the fan-shaped plate decreases, the bottom surface of the hot end fan-shaped plate is not a plane in the hot state, but a downward curved surface, making the air leakage problem at the hot end of the air preheater more prominent.

[0004] In order to reduce the area of ​​the above-mentioned air leakage area and reduce the air leakage rate of the air preheater, two technical routes are generally adopted in the current engineering: one is the fan plate automatic tracking system (LCS for short) equipped by the three major domestic main engine manufacturers (Dongguo, Harbin and Shangguo); the other is the flexible sealing technology developed in recent years. This actually reflects two aspects of a problem: the air preheater sealing problem is the problem of matching the sealing sheet with the fan plate. The automatic adhesion of the sealing sheet to the fan plate and the automatic tracking of the fan plate by the fan plate can achieve the purpose of reducing air leakage. However, both of these solutions have the following problems in engineering applications: Affected by various factors such as harsh working conditions (high temperature, dust, etc.), maintenance quality, and management level, most power plant LCS systems cannot be put into operation normally or the operation effect is not ideal. HOWDEN has not equipped the air preheater with LCS, which also shows from the side that this technology needs to be further improved. The traditional flexible sealing technology has exposed problems such as excessive wear, unreliable structure, and insufficient gap compensation.

[0005] In short, the air leakage problem in the radial air leakage area at the hot end has not been completely solved. Moreover, as the units develop towards larger capacity, the diameter of the air preheater rotor continues to increase. If no measures are taken, the air leakage share in the radial air leakage area at the hot end will increase. The radial air leakage at the hot end of the air preheater equipped with units of 600MW and above accounts for more than 50% of the total air leakage, and the absolute air leakage to the flue gas side also exceeds 3%, and the primary air leakage rate may exceed 30%. Summary of the invention

[0006] The present invention provides a radial arc sealing device for the hot end of an air preheater and an installation structure thereof, which can cooperate with the deformation characteristic that the bottom surface of the fan-shaped plate at the hot end of the air preheater bends downward in the hot state, thereby reducing the air leakage gap and significantly reducing the air leakage rate of the air preheater.

[0007] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A radial arc sealing device for the hot end of an air preheater, comprising a sealing sheet, a fixed clamping plate, a first driving clamping plate, a second driving clamping plate and a wrapping sheet;

[0009] The sealing sheet, the fixed clamping plate, the first driving clamping plate, the second driving clamping plate and the wrapping sheet are all provided with waist-shaped holes;

[0010] The sealing sheet, the fixing clamping plate and the wrapping sheet are made of the same material, which is the first material; the first driving clamping plate and the second driving clamping plate are made of the same material, which is the second material; and the expansion coefficient of the first material is smaller than the expansion coefficient of the second material;

[0011] One end of the sealing sheet and the wrapping sheet in the length direction is defined as the starting end, and the other end in the length direction is defined as the terminal end. The sealing sheet and the wrapping sheet are arranged opposite to each other. The number of waist-shaped holes on the sealing sheet and the wrapping sheet is equal and one-to-one corresponding. One end of the sealing sheet in the width direction exceeds the wrapping sheet to form a sealing end. The sealing end on the sealing sheet is defined as the top, and the other end is defined as the bottom. The sealing end of the sealing sheet is provided with a stress splitting seam starting from the top.

[0012] There are more than two first drive splints and second drive splints, and the length of the first drive splint is greater than that of the second drive splint; there is one fixed splint; the fixed splint, the first drive splint and the second drive splint are all arranged between the sealing sheet and the wrapping sheet, and the fixed splint, the first drive splint and the second drive splint are arranged in sequence from the starting end to the end end of the sealing sheet, and the length of the fixed splint is 1 / 5 to 2 / 5 of the length of the sealing sheet; the fixed splint is welded to the sealing sheet and the wrapping sheet; the first drive splint and the second drive splint are welded to the sealing sheet and the wrapping sheet at both ends of the bottom and the middle point of the top, that is, the first drive splint and the second drive splint are connected to the sealing sheet and the wrapping sheet by three-point welding;

[0013] The waist-shaped holes on the fixed splint correspond one to one to the waist-shaped holes on the sealing sheet opposite to it; the first driving splint and the second driving splint opposite to the waist-shaped holes on the sealing sheet are also provided with corresponding waist-shaped holes, and the waist-shaped holes of the sealing sheet and the wrapping sheet corresponding to the waist-shaped holes of the first driving splint and the second driving splint are provided with expansion gaps communicating with the waist-shaped holes above and below, and the expansion gaps below the waist-shaped holes of the sealing sheet and the wrapping sheet run through the bottom of the sealing sheet and the wrapping sheet, while no expansion gaps are provided on the waist-shaped holes of the sealing sheet and the wrapping sheet corresponding to the waist-shaped holes of the fixed splint.

[0014] By setting the first driving clamp and the second driving clamp, the driving expansion amount of the sealing plate at the maximum deformation position is increased, which can offset the sagging caused by gravity to a greater extent and improve the sealing effect. At the same time, it can ensure that the curvature of the sealing plate in the hot state is within the design range, which can avoid collision and friction caused by excessive deformation and maximize the sealing effect.

[0015] The arrangement of the stress separation seam at the top of the sealing sheet can effectively reduce the overall stress damage caused by seal collision and wear, thereby increasing the service life of the seal.

[0016] No expansion gap is provided on the waist-shaped holes of the sealing sheet and the wrapping sheet corresponding to the waist-shaped holes of the fixed splint. Only expansion gaps connected to the waist-shaped holes are provided above and below the waist-shaped holes of the sealing sheet and the wrapping sheet corresponding to the waist-shaped holes of the first driving splint or the second driving splint. This can better compensate for the triangular air leakage area formed in the hot state to reduce air leakage.

[0017] When in use, the length direction of the sealing sheet is consistent with the radial direction of the rotor, and the fixed clamping plate, the first driving clamping plate, and the second driving clamping plate are arranged in sequence from inside to outside along the radial direction of the rotor.

[0018] The sealing sheet, the fixed clamping plate, the first driving clamping plate, the second driving clamping plate and the wrapping sheet of the present application are all in the same length direction.

[0019] The fixed clamp is clamped between the sealing plate and the wrapping plate and fixed by welding. There is no requirement for the position of the welding points. The first driving clamp and the second driving clamp are only welded to the sealing plate and the wrapping plate at the two ends of the bottom and the middle point of the top. Welding is not allowed at other positions, that is, three-point welding is required.

[0020] By adjusting the width and number of the first drive splint and the second drive splint, it is ensured that when in hot state, the radial arc sealing device at the hot end of the air preheater is arc-shaped with an arc height of 5-15mm. As one of the specific implementation schemes, each first drive splint and the second drive splint respectively corresponds to a waist-shaped hole on the sealing sheet; except for the last waist-shaped hole on the sealing sheet (the last waist-shaped hole located at the terminal), each waist-shaped hole corresponds to a fixed splint, a first drive splint or a second drive splint; the number of first drive splints and second drive splints is equal; the length of the first drive splint is 1.8 to 2.2 times the length of the second drive splint. The above scheme can better ensure the arc structure of the sealing device in the hot state and improve the sealing performance.

[0021] More preferably, the thermal expansion coefficient of the first material at 350°C is α=(11.5±0.5)×10 -6 / ℃; thermal expansion coefficient of the second material at 350℃ α=(17.33±0.5)×10 -6 / ℃.

[0022] As one specific implementation scheme, the center distance between two adjacent waist-shaped holes on the sealing sheet is 300±10 mm; the length of the second driving clamping plate is 110-130 mm.

[0023] In order to better balance the sealing performance and service life, a stress dividing seam is provided between every two adjacent waist-shaped holes on the sealing sheet.

[0024] In order to avoid collision and wear, the sealing end of the sealing sheet forms a bending angle of 15±2°.

[0025] The installation structure of the radial arc sealing device at the hot end of the air preheater is installed on the hot end radial partition plate by means of fixing bolts passing through the waist-shaped holes. The radial arc sealing device at the hot end of the air preheater and the hot end sector plate of the air preheater form a sealing pair. The length direction of the sealing sheet is consistent with the radial length of the air preheater rotor.

[0026] In the part with the fixed splint, the fixing bolts pass through the waist-shaped holes on the sealing plate, the fixed splint and the wrapping plate at the same time, and are locked by nuts; in the part with the first driving splint, the fixing bolts pass through the waist-shaped holes on the sealing plate, the first driving splint and the wrapping plate at the same time, and are not completely locked by nuts; in the part with the second driving splint, the fixing bolts pass through the waist-shaped holes on the sealing plate, the second driving splint and the wrapping plate at the same time, and are not completely locked by nuts.

[0027] After heating, since the expansion coefficient of the driving splint is greater than that of the sealing plate, the middle part of the sealing plate will bend downward and deform, showing the same trend as the deformation of the hot end fan plate, thereby eliminating the traditional triangular air leakage area of ​​the air preheater and significantly reducing the air leakage rate of the air preheater.

[0028] In order to ensure that the fixing bolts on the waist-shaped holes of the first drive splint and the second drive splint are not completely locked, the corresponding waist-shaped holes on the sealing sheet, the drive splint and the wrapping sheet are all distributed with corresponding ball mounting holes around them. The corresponding ball mounting holes on the sealing sheet, the drive splint and the wrapping sheet form a group of ball mounting holes. The diameter of the ball mounting holes on the outside of the sealing sheet and the wrapping sheet is smaller than the ball diameter. There are more than 3 groups of ball mounting holes distributed around each waist-shaped hole. Each group of ball mounting holes is equipped with a ball, and the two sides of the ball exceed the sealing sheet and the wrapping sheet by 0.25 to 0.75 mm respectively; the drive splint includes the first drive splint and the second drive splint. That is, the ball diameter is 0.5-1.5 mm larger than the sum of the thicknesses of the sealing sheet, the wrapping sheet and the first drive splint or the second drive splint.

[0029] In order to improve balance, there are more than 4 groups of ball mounting holes distributed around each waist-shaped hole.

[0030] When the deformation of the radial arc sealing device at the hot end of the air preheater is greater than the sealing gap, in order to ensure that the sealing plate does not rub against the fan plate, the above-mentioned installation structure also includes a limit plate, on which a long limit hole is provided. The limit plate is located on the last waist-shaped hole at the terminal of the radial arc sealing device at the hot end of the air preheater. The fixing bolts pass through the sealing plate, the wrapping plate and the long limit hole on the limit plate in turn and are fixed with nuts. The limit plate is welded to the wrapping plate.

[0031] The technologies not mentioned in the present invention are all referred to the prior art.

[0032] The radial arc sealing device and installation structure of the hot end of the air preheater of the present invention can cooperate with the deformation characteristic that the bottom surface of the fan-shaped plate at the hot end of the air preheater bends downward in the hot state, thereby reducing the air leakage gap and significantly reducing the air leakage rate of the air preheater. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of the sealing sheet structure of the present invention;

[0034] Figure 2 for Figure 1 The enlarged schematic diagram at A in the middle;

[0035] Figure 3 for Figure 1 The enlarged schematic diagram of point B in the middle;

[0036] Figure 4 It is a schematic diagram of the arrangement of the fixed clamping plate, the first driving clamping plate and the second driving clamping plate of the present invention;

[0037] Figure 5 is a schematic diagram of the structure of the first driving clamp;

[0038] Figure 6 is a schematic diagram of the structure of the second driving clamp;

[0039] Figure 7 This is a schematic diagram of the structure of the wrapping sheet of the present invention;

[0040] Figure 8 A perspective view of the radial arc sealing device at the hot end of the air preheater of the present invention;

[0041] Fig. 9 It is a schematic diagram of the installation structure of the radial arc sealing device at the hot end of the air preheater of the present invention;

[0042] Fig.10 It is a schematic diagram of the installation of the ball of the present invention;

[0043] Fig.11 It is a schematic diagram of the structure of the limiting piece of the present invention;

[0044] Fig.12 It is a schematic diagram of the hot end radial baffle and the sealing sheet in the hot state of the present invention;

[0045] Fig.13 This is a schematic diagram of the thermal expansion of the second driving splint of the present invention;

[0046] Fig.14 This is a simulation result diagram of the installation structure of the radial arc sealing device at the hot end of the air preheater of the present invention;

[0047] In the figure, 1 is a sealing plate, 101 is a stress dividing seam, 2 is a fixed splint, 3 is a first driving splint, 4 is a second driving splint, 401 is a driving force, 402 is an opening at a certain angle, 403 is an upward deformation, 5 is a wrapping plate, 6 is a waist-shaped hole, 601 is an expansion gap, 7 is a ball, 8 is a hot end radial partition, 9 is a hot end fan-shaped plate, 10 is a limiting plate, 1001 is a limiting hole, and 11 is a fixing bolt. DETAILED DESCRIPTION

[0048] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the embodiments, but the content of the present invention is not limited to the following embodiments.

[0049] In this application, directional words such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or position relationship shown in the drawings or in use, and are only for the convenience of describing the application, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the application.

[0050] Example 1

[0051] like Figure 1-8 As shown, a radial arc sealing device for the hot end of an air preheater comprises a sealing sheet, a fixed clamping plate, a first driving clamping plate, a second driving clamping plate and a wrapping sheet;

[0052] The sealing sheet, the fixed clamping plate, the first driving clamping plate, the second driving clamping plate and the wrapping sheet are all provided with waist-shaped holes;

[0053] The sealing sheet, the fixing clamping plate and the wrapping sheet are made of the same material, which is the first material; the first driving clamping plate and the second driving clamping plate are made of the same material, which is the second material; and the expansion coefficient of the first material is smaller than the expansion coefficient of the second material;

[0054] One end of the sealing sheet and the wrapping sheet in the length direction is defined as the starting end, and the other end in the length direction is defined as the terminal end. The sealing sheet and the wrapping sheet are arranged opposite to each other. The number of waist-shaped holes on the sealing sheet and the wrapping sheet is equal and one-to-one corresponding. One end of the sealing sheet in the width direction exceeds the wrapping sheet to form a sealing end. The sealing end on the sealing sheet is defined as the top, and the other end is defined as the bottom. The sealing end of the sealing sheet is provided with a stress splitting seam starting from the top, and the length (height) of the stress splitting seam is 20 mm.

[0055] There are more than two first drive splints and second drive splints, and the length of the first drive splint is greater than that of the second drive splint; there is one fixed splint; the fixed splint, the first drive splint and the second drive splint are all arranged between the sealing sheet and the wrapping sheet, and the fixed splint, the first drive splint and the second drive splint are arranged in sequence from the starting end to the end end of the sealing sheet, and the length of the fixed splint is 1 / 5 to 2 / 5 of the length of the sealing sheet; the fixed splint is welded to the sealing sheet and the wrapping sheet; the first drive splint and the second drive splint are welded to the sealing sheet and the wrapping sheet at both ends of the bottom and the middle point of the top, that is, the first drive splint and the second drive splint are connected to the sealing sheet and the wrapping sheet by three-point welding;

[0056] The waist-shaped holes on the fixed splint correspond one to one to the waist-shaped holes on the sealing sheet opposite to it; the first driving splint and the second driving splint opposite to the waist-shaped holes on the sealing sheet are also provided with corresponding waist-shaped holes, and the waist-shaped holes of the sealing sheet and the wrapping sheet corresponding to the waist-shaped holes of the first driving splint and the second driving splint are provided with expansion gaps communicating with the waist-shaped holes above and below, and the expansion gaps below the waist-shaped holes of the sealing sheet and the wrapping sheet run through the bottom of the sealing sheet and the wrapping sheet, while no expansion gaps are provided on the waist-shaped holes of the sealing sheet and the wrapping sheet corresponding to the waist-shaped holes of the fixed splint.

[0057] Example 2

[0058] Based on Example 1, the following improvements are made: the thermal expansion coefficient of the first material is α=11.5×10 -6 / ℃(350℃), the thermal expansion coefficient of the second material α=17.33×10 -6 / ℃(350℃); total length of sealing sheet L=5446mm, height h=130mm, waist-shaped hole center distance d=300mm, 19 waist-shaped holes in total, thickness 2.5mm, bending angle of sealing end 15°; wrapping sheet: thickness 2.5mm, h=100mm, with 19 waist-shaped holes corresponding to the waist-shaped holes on the sealing sheet; fixed splint covers 6 waist-shaped holes of the sealing sheet from the beginning of the sealing sheet; the thickness of the first driving splint is 3mm, L=240mm, 6 pieces in total, the thickness of the second driving splint is 3mm, L=120mm, 6 pieces in total, each of the first driving splint and the second driving splint corresponds to a waist-shaped hole on the sealing sheet, that is, only the last waist-shaped hole is not provided with a driving splint; on the sealing sheet, a stress dividing seam is provided between each two adjacent waist-shaped holes; such as Fig.12 As shown, at 350℃ hot state, the radial arc sealing device at the hot end of the air preheater is arc-shaped with an arc height of 5-15mm. Fig.12 A schematic diagram with shortened length.

[0059] Example 3

[0060] Embodiment 2 The installation structure of the radial arc sealing device at the hot end of the hollow preheater, such as Fig. 9 As shown, it is installed on the hot end radial partition plate through the fixing bolts passing through the waist-shaped holes. The radial arc sealing device at the hot end of the air preheater and the hot end fan plate of the air preheater form a sealing pair. The length direction of the sealing sheet is consistent with the radial length of the air preheater rotor.

[0061] In the part with the fixed splint, the fixing bolts pass through the waist-shaped holes on the sealing plate, the fixed splint and the wrapping plate at the same time, and are locked by nuts; in the part with the first driving splint, the fixing bolts pass through the waist-shaped holes on the sealing plate, the first driving splint and the wrapping plate at the same time, and are not completely locked by nuts; in the part with the second driving splint, the fixing bolts pass through the waist-shaped holes on the sealing plate, the second driving splint and the wrapping plate at the same time, and are not completely locked by nuts.

[0062] Example 4

[0063] On the basis of Example 3, the following improvements are further made: To ensure that the fixing bolts on the waist-shaped holes of the first driving splint and the second driving splint are not completely locked, Fig.10As shown, the corresponding waist-shaped holes on the sealing sheet, the driving splint and the wrapping sheet are all distributed with corresponding ball mounting holes around them. The corresponding ball mounting holes on the sealing sheet, the driving splint and the wrapping sheet form a group of ball mounting holes. The diameter of the ball mounting holes on the outside of the sealing sheet and the wrapping sheet is smaller than the ball diameter, that is, the ball will not fall from the side of the sealing sheet and the wrapping sheet. There are 4 groups of ball mounting holes distributed around each waist-shaped hole. Each group of ball mounting holes is equipped with a ball, and the two sides of the ball exceed the sealing sheet and the wrapping sheet by 0.25 to 0.75 mm respectively; the driving splint includes a first driving splint and a second driving splint. That is, the ball diameter is 0.5-1.5 mm larger than the sum of the thicknesses of the sealing sheet, the wrapping sheet and the first driving splint or the second driving splint.

[0064] Example 5

[0065] On the basis of Example 4, the following improvements were made: Fig.11 As shown, the installation structure of the radial arc sealing device at the hot end of the air preheater also includes a limit plate, on which a long limit hole is provided. The limit plate is located on the last waist-shaped hole at the terminal of the radial arc sealing device at the hot end of the air preheater. The fixing bolts pass through the waist-shaped hole of the sealing plate, the waist-shaped hole of the wrapping plate and the long limit hole on the limit plate in sequence and are fixed with nuts. The limit plate is welded to the wrapping plate.

[0066] like Fig.13 As shown, the sealing sheet is provided with a 0.2 mm wide expansion gap in the middle of the upper and lower parts, and the thermal expansion coefficients of the first driving splint and the second driving splint are greater than the expansion coefficient of the sealing sheet. When the temperature rises, the thermal expansion generated by the two welding points at the bottom of the driving splint will be greater than the expansion of the sealing sheet between these welding points. Under the driving force of the internal thermal expansion, the sealing sheet will open to both sides at a certain angle at the expansion gap, causing both sides of the driving sheet to deform upward.

[0067] Four ball mounting holes are arranged around the waist-shaped holes provided with the first driving clamping plate and the second driving clamping plate, and balls are clamped therein. The diameter of the ball is slightly larger than the overall thickness of the radial arc sealing device at the hot end of the air preheater. The surface contact between the sealing plate and the partition is changed to point contact, which greatly reduces the force area and reduces the friction between the two. At the same time, due to the rolling characteristics of the steel column, the friction between the seal and the partition is further reduced, thereby ensuring the reliability of the seal during thermal compensation.

[0068] like Figure 1As shown, by setting the stress separation seam on the sealing plate, the overall stress damage caused by the seal collision and wear is reduced, and the service life of the seal is increased. When the seal is a whole, the compression of one point will cause the entire seal to receive stress, which will cause the seal to be subjected to stress changes as a whole, and long-term collision and wear will lead to a reduction in the service life of the seal. In order to avoid the overall stress deformation caused by the collision and wear of the sealing plate and the fan plate, a stress separation seam with a width of 0.2mm is provided between each two adjacent waist-shaped holes on the sealing plate. When a point collision causes stress changes, the stress will be dispersed on the bending sheet of the separation seam, and the maximum stress point is located at the location of the contact point, rather than the entire sealing plate receiving stress extrusion at the same time. According to the rotation direction of the rotor, along the bending direction of the sealing plate, the collision point is compressed and deformed step by step from the center tube to the outside, which will not cause the overall seal stress deformation, thereby extending the service life of the seal.

[0069] like Fig.11 As shown, a sealing deformation limiter is provided to constrain the maximum deformation of the sealing piece to ensure safe operation. When the deformation of the radial arc sealing device at the hot end of the air preheater is greater than the sealing gap, in order to ensure that the sealing piece does not rub against the fan plate, a deformation limiter is installed at the last bolt hole position of the terminal of the radial arc sealing device at the hot end of the air preheater. After the gap is adjusted, the limiter is freely suspended on the fixing bolt and locked, and is welded and fixed to the wrapping piece. A long limit hole is reserved in the middle of the sealing limiter, and the gap value between the limiter hole and the fixing bolt is the limit value of the maximum upward deformation of the sealing piece. When the sealing deformation exceeds the gap of this limiter hole, the sealing piece will be constrained and will no longer expand upward, thereby ensuring the set sealing gap and ensuring the safe operation of the equipment.

[0070] Fig.14 The simulation result diagram of the installation structure of the above installation structure, the hot end is 350℃, the cold end is 80℃, the simulation calculation result of the seal sheet deformation variable is: Max=10.307mm; simulate the air preheater rotor diaphragm structure, test the thermal deformation result of the above installation structure, the result is consistent with Fig.13 The trend of the modeling calculation results is consistent with that of the previous one. Practice shows that by arranging the first driving splint and the second driving splint in a specific order, combined with the improvement of the sealing sheet structure, it is possible to avoid friction and maximize the improvement of the sealing effect. If the above-mentioned second driving splints are replaced with the first driving splints, the simulation calculation results of the deformation of the sealing sheet are: Max = 16.465mm, the deformation is too large, and it is easy to cause friction; if the above-mentioned first driving splints are replaced with the second driving splints, the simulation calculation results of the deformation of the sealing sheet are: Max = 4.387mm, the deformation is too small, and the improvement of sealing is not obvious;

[0071] The air preheater of the 600MW unit of the #7 furnace of a power plant was renovated. The average air leakage rate on the A / B side was 7% before the renovation. After the sealing renovation according to the scheme in this example, it was reduced to about 4%. The renovation benefits are expected to be as follows:

[0072] Coal saving benefit = 600MW × 6000h / year × (7-4) × 0.2 × 10 -6 t / kWh×700 yuan / t=1.512 million yuan / year;

[0073] Power saving income = 10A × 6.3kV × 31 / 2 × 0.85 × 6000h / year × (7-4) × 0.35 yuan / kWh × 2 units = 1.168 million yuan / year;

[0074] The direct economic benefits of the 600MW unit air preheater sealing transformation = coal saving benefits + electricity saving benefits = 2.68 million yuan / year.

[0075] illustrate:

[0076] 1) "For every 1% increase (decrease) in the air preheater leakage rate, the power generation coal consumption rate increases (decreases) by 0.20g / kWh." From "Handbook of Energy Conservation Evaluation and Energy Audit of Thermal Power Plants" / edited by Li Chun, Zhang Xingying, and Liu Xuebing / P41.

[0077] 2) "For every 1% decrease in the air preheater leakage rate, the current of the three large fans using a 6.3kV three-phase power supply decreases by 15 to 25A" (the two fans are calculated here as 20A×2=40A, and the power factor is 0.85. The unit price of standard coal is 700 yuan / ton; the annual utilization hours of the computer group: 6000 hours / year; the average on-grid electricity price is 0.35 yuan / kWh).

Claims

1. A radial arc sealing device for the hot end of an air preheater, characterized in that: It includes a sealing sheet, a fixing clamping plate, a first driving clamping plate, a second driving clamping plate and a wrapping sheet; The sealing sheet, the fixed clamping plate, the first driving clamping plate, the second driving clamping plate and the wrapping sheet are all provided with waist-shaped holes; The sealing sheet, the fixing clamping plate and the wrapping sheet are made of the same material, which is the first material; the first driving clamping plate and the second driving clamping plate are made of the same material, which is the second material; and the expansion coefficient of the first material is smaller than the expansion coefficient of the second material; One end of the sealing sheet and the wrapping sheet in the length direction is defined as the starting end, and the other end in the length direction is defined as the terminal end. The sealing sheet and the wrapping sheet are arranged opposite to each other. The number of waist-shaped holes on the sealing sheet and the wrapping sheet is equal and one-to-one corresponding. One end of the sealing sheet in the width direction exceeds the wrapping sheet to form a sealing end. The sealing end on the sealing sheet is defined as the top, and the other end is defined as the bottom. The sealing end of the sealing sheet is provided with a stress splitting seam starting from the top. There are more than two first drive splints and second drive splints, and the length of the first drive splint is greater than that of the second drive splint; there is one fixed splint; the fixed splint, the first drive splint and the second drive splint are arranged between the sealing sheet and the wrapping sheet, and the fixed splint, the first drive splint and the second drive splint are arranged in sequence from the starting end to the end end of the sealing sheet, and the length of the fixed splint is 1 / 5 to 2 / 5 of the length of the sealing sheet; the fixed splint is welded to the sealing sheet and the wrapping sheet; both ends of the bottom and the middle point of the top of the first drive splint and the second drive splint are welded to the sealing sheet and the wrapping sheet; The waist-shaped holes on the fixed splint correspond one to one to the waist-shaped holes on the sealing sheet opposite to it; the first driving splint and the second driving splint opposite to the waist-shaped holes on the sealing sheet are also provided with corresponding waist-shaped holes, and the waist-shaped holes of the sealing sheet and the wrapping sheet corresponding to the waist-shaped holes of the first driving splint and the second driving splint are provided with expansion gaps communicating with the waist-shaped holes above and below, and the expansion gaps below the waist-shaped holes of the sealing sheet and the wrapping sheet run through the bottom of the sealing sheet and the wrapping sheet, while no expansion gaps are provided on the waist-shaped holes of the sealing sheet and the wrapping sheet corresponding to the waist-shaped holes of the fixed splint.

2. The radial arc sealing device for the hot end of an air preheater according to claim 1, characterized in that: When hot, the radial arc sealing device at the hot end of the air preheater is arc-shaped with an arc height of 5-15mm.

3. The radial arc sealing device for the hot end of an air preheater according to claim 1 or 2, characterized in that: On the sealing sheet, a stress dividing seam is provided between each two adjacent waist-shaped holes; each first driving splint and second driving splint respectively corresponds to a waist-shaped hole on the sealing sheet; except for the last waist-shaped hole on the sealing sheet, each waist-shaped hole corresponds to a fixed splint, a first driving splint or a second driving splint.

4. The radial arc sealing device for the hot end of an air preheater according to claim 1 or 2, characterized in that: The number of the first driving splints and the second driving splints is equal; the length of the first driving splint is 1 to 2.5 times the length of the second driving splint, and the aforementioned range value does not include the endpoint 1.

5. The radial arc sealing device for the hot end of an air preheater according to claim 4, characterized in that: The center distance between two adjacent waist-shaped holes on the sealing sheet is 300±50mm; the length of the second driving clamping plate is 110~130mm; and the sealing end of the sealing sheet forms a bending angle of 15±3°.

6. The radial arc sealing device for the hot end of an air preheater according to claim 1 or 2, characterized in that: Thermal expansion coefficient of the first material at 350°C α = (11.5 ± 1) × 10 -6 / ℃; thermal expansion coefficient of the second material at 350℃ α = (17.33 ± 1) × 10 -6 / ℃.

7. The installation structure of the radial arc sealing device at the hot end of the air preheater according to any one of claims 1 to 6, characterized in that: The hot end radial partition is installed by fixing bolts passing through the waist-shaped holes. The hot end radial arc sealing device of the air preheater and the hot end fan plate of the air preheater form a sealing pair. The length direction of the sealing sheet is consistent with the radial length of the air preheater rotor. In the part with the fixed splint, the fixing bolts pass through the waist-shaped holes on the sealing plate, the fixed splint and the wrapping plate at the same time, and are locked by nuts; in the part with the first driving splint, the fixing bolts pass through the waist-shaped holes on the sealing plate, the first driving splint and the wrapping plate at the same time, and are not completely locked by nuts; in the part with the second driving splint, the fixing bolts pass through the waist-shaped holes on the sealing plate, the second driving splint and the wrapping plate at the same time, and are not completely locked by nuts.

8. The mounting structure according to claim 7, characterized in that: Corresponding ball mounting holes are distributed around the corresponding waist-shaped holes on the sealing plate, driving splint and wrapping plate. The corresponding ball mounting holes on the sealing plate, driving splint and wrapping plate form a group of ball mounting holes. The hole diameters of the ball mounting holes on the outsides of the sealing plate and the wrapping plate are smaller than the diameter of the ball. There are more than 3 groups of ball mounting holes distributed around each waist-shaped hole. A ball is arranged in each group of ball mounting holes, and both sides of the ball extend beyond the sealing plate and the wrapping plate by 0.25~0.75mm respectively; the driving splint includes a first driving splint and a second driving splint.

9. The mounting structure according to claim 8, characterized in that: More than 4 groups of ball mounting holes are evenly distributed around each waist-shaped hole.

10. The mounting structure according to any one of claims 7 to 9, characterized in that: It also includes a limit plate, which is provided with a long limit hole. The limit plate is located on the last waist-shaped hole at the terminal of the radial arc sealing device at the hot end of the air preheater. The fixing bolts pass through the sealing plate, the wrapping plate and the long limit holes on the limit plate in turn and are fixed with nuts. The limit plate is welded to the wrapping plate.

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