Hot-end sealing device of air preheater with expansion difference compensation between sealing sheet and backing plate

Abstract

The present invention discloses a hot-end sealing device for an air preheater that compensates for the expansion difference between a sealing sheet and a backing plate, which at least includes a sealing sheet and a backing plate. The sealing sheet is provided with sealing sheet mounting holes distributed along the length direction, and the backing plate is provided with backing plate mounting holes distributed along the length direction. The linear expansion coefficient of the sealing sheet is different from that of the backing plate. The sealing sheet and the backing plate are relatively fixed by clamping bolts that simultaneously pass through the sealing sheet mounting holes and the backing plate mounting holes. One end close to the rotor central cylinder is the expansion starting end, and the clamping bolts at the expansion starting end are fully tightened and fixed, while the remaining clamping bolts are not fully tightened and fixed, so that the sealing sheet and the backing plate freely expand towards the other end close to the rotor outer edge angle steel after being heated. At least one set of two-dimensional guiding mechanisms is arranged between the sealing sheet and the backing plate downstream of the expansion starting end. The above device maximally compensates for the triangular air leakage area at the hot end of the air preheater, significantly reduces the air leakage rate of the air preheater, has good stability and a long service life.

Description

Technical Field

[0001] The present invention relates to a hot-end sealing device for an air preheater that compensates for the expansion difference between a sealing sheet and a backing plate, and belongs to the field of sealing devices. Background Art

[0002] A rotary air preheater is a heat exchange device applied to 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 rotor of the air preheater changes from the cold state to the hot state, due to the different temperatures of the upper and lower end faces and the weakening of the rigidity of the steel after heating, a "mushroom-shaped" deformation occurs. The traditional rigid sealing sheet is fixed to the rotor partition by bolts in sections. As the rotor partition deforms, the leakage gap also changes accordingly. Based on the mechanism of the "mushroom-shaped" deformation of the rotor, appropriate cold-state gaps are reserved at the axial and cold-end radial positions, and the dynamic and static mating gaps tend to zero in the hot state; although the cold-state reserved gap at the hot-end radial position is very small, a large triangular leakage area will be formed in the hot state.

[0003] To reduce the area of the above triangular leakage area and the air leakage rate of the air preheater, generally two technical routes are adopted in current engineering: one is the sector plate automatic tracking system (abbreviated as LCS) equipped by the three major domestic mainframe manufacturers (Dongfang Boiler, Harbin Boiler, and Shanghai Boiler); the other is the flexible sealing technology developed in recent years.

[0004] It is not difficult to understand that this actually reflects two aspects of a problem: the air preheater sealing problem is the problem of the cooperation between the sealing sheet and the sector plate. The purpose of reducing air leakage can be achieved by the sealing sheet automatically clinging to the sector plate and the sector plate automatically tracking the sealing sheet. However, both of these two 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, the LCS systems of the vast majority of power plants cannot be put into operation normally or the operation effect is not ideal. HOWDEN, the world's leading rotary air preheater supplier, has never 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 even more exposes problems such as excessive wear, unreliable structure, and insufficient gap compensation, and simply cannot meet the engineering requirements.

[0005] In short, the air leakage problem in the hot-end radial triangular leakage area has not been completely solved. Moreover, as the unit develops towards a large capacity, the diameter of the air preheater rotor continues to increase. If no measures are taken, the air leakage share in the hot-end radial triangular leakage area will become larger and larger. For example, when using the traditional rigid sealing sheet and the hot-end sector plate is not adjustable, the outermost gap at the hot-end radial of a 300MW unit exceeds 10mm, that of a 600MW unit exceeds 25mm, and the gap of a 1000MW unit is about 50mm. The hot-end radial triangular air leakage of the air preheater equipped with 600MW and above units accounts for more than 50% of the total air leakage volume, and the absolute air leakage volume 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 hot-end seal device for an air preheater that compensates for the expansion difference between a sealing sheet and a backing plate. It is installed on the hot-end radial partition of the air preheater rotor and is used to eliminate the triangular air leakage area generated by the air preheater due to heat, and significantly reduce the air leakage rate of the air preheater.

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

[0008] A hot-end seal device for an air preheater that compensates for the expansion difference between a sealing sheet and a backing plate is installed on the hot-end radial partition of the air preheater rotor. One end is close to the rotor central cylinder, and the other end is close to the rotor outer edge angle steel. It at least includes a sealing sheet and a backing plate arranged along the thickness direction. The sealing sheet is provided with sealing sheet mounting holes distributed along the length direction, and the backing plate is provided with backing plate mounting holes distributed along the length direction. The linear expansion coefficient of the sealing sheet is different from that of the backing plate; the backing plate is arranged along the length direction of the sealing sheet and is relatively fixed by clamping bolts that simultaneously pass through the sealing sheet mounting holes and the backing plate mounting holes; the end close to the rotor central cylinder is the expansion starting end, and the clamping bolts at the expansion starting end are completely tightened and fixed, while the other clamping bolts are not completely tightened and fixed, so that the sealing sheet and the backing plate freely expand towards the other end close to the rotor outer edge angle steel after being heated; at least one set of two-dimensional guiding mechanisms is arranged between the sealing sheet and the backing plate downstream of the expansion starting end.

[0009] The linear expansion coefficient of the above-mentioned sealing sheet is different from that of the backing plate, that is, the linear expansion coefficient of the sealing sheet is greater than that of the backing plate, or the linear expansion coefficient of the backing plate is greater than that of the sealing sheet.

[0010] Completely tightening and fixing the clamping bolts means that there is no margin for further tightening of the clamping bolts, that is, the layers are completely fitted and locked; not completely tightening and fixing the clamping bolts means that there is a margin for further tightening of the clamping bolts, that is, the layers are not completely fitted and locked, and relative movement can occur within a certain range when deformation occurs due to temperature changes.

[0011] The length direction of the sealing sheet is consistent with the radial direction of the air preheater rotor; in the radial direction of the air preheater rotor, the direction from the rotor central cylinder to the rotor outer edge angle steel is defined as the direction from upstream to downstream.

[0012] The applicant has found through research that the expansion amount of the sealing sheet along the radial direction of the air preheater rotor is greater than that of the backing plate. By using the two-dimensional guiding mechanism to convert the horizontal radial relative displacement into a vertical axial upward displacement and simultaneously form a misaligned displacement, the triangular air leakage area at the hot end of the air preheater can be effectively compensated. The deformation of the above-mentioned seal device and the mushroom-shaped deformation of the air preheater are both driven by heat, and the two deformation directions are opposite and synchronous, so as to keep the radial clearance at the hot end of the air preheater always maintained at a relatively small level.

[0013] Through the setting of the two-dimensional guiding mechanism in this application, when expanding or contracting, the sealing piece and the backing plate slide along a specific path, which can not only ensure the stability of operation, but also accurately control the displacement amount, and then accurately control the compensation amount, avoiding the problems of excessive or insufficient compensation. While effectively reducing the air leakage rate of the air preheater, the safe and stable operation of the air preheater is ensured.

[0014] To improve the thermal deformation stability of the driving piece and the sealing piece, preferably, a pressing plate is further included, and the backing plate, the sealing piece and the pressing plate are relatively fixed in sequence along the thickness direction through clamping bolts.

[0015] To prevent the abnormal deformation of the above-mentioned sealing piece from causing malignant rubbing against the sector plate of the air preheater, preferably, at least one set of roller mechanisms is installed at the upper edge of the sealing piece and at one end close to the outer edge angle steel of the rotor. The vertex of the roller is not lower than the upper edge of the sealing piece. Once the sealing piece rubs against the sector plate, the roller first contacts the sector plate, so as to ensure that the sealing piece is not severely damaged.

[0016] The direction from top to bottom of the sealing piece is perpendicular to the length direction of the sealing piece.

[0017] To obtain appropriate and stable deformation characteristics of the sealing device, preferably, the two-dimensional guiding mechanism includes a guide rail and a guiding block. The stroke of the guide rail is a straight line or a curve, and the angle between the stroke of the guide rail or the tangent of the stroke of the guide rail and the horizontal plane (or the length direction of the sealing piece) is not less than 10° and not more than 70°. The larger this angle is, the larger the amount of horizontal displacement converted into the vertical position. Determine the angle of the stroke of the guide rail according to the specific size of the triangular air leakage area of the air preheater to achieve the maximum compensation for the triangular air leakage area, minimize the air leakage rate, and at the same time, avoid excessive compensation resulting in rubbing to ensure safety. In addition, when the stroke of the guide rail is a straight line, the horizontal expansion amount is converted into the vertical compensation amount at a fixed ratio, and when it is a non-straight stroke, the conversion of the horizontal expansion amount into the vertical compensation amount is also non-linear. Specifically, select a straight line or a curve for the stroke of the guide rail according to the temperature change characteristics of the air preheater. Select a straight line when the linear relationship between the cold and hot end temperature difference and the hot end temperature is good, and select a curve when it is significantly non-linear.

[0018] For the convenience of installation, the guide rail of the two-dimensional guiding mechanism is arranged on the sealing piece, and the guiding block is arranged on the backing plate.

[0019] The two-dimensional guiding mechanism can be set into various structures. For the convenience of manufacturing, a guide rail with an inclined surface structure is provided on the sealing piece, and a guiding block matching the guide rail is provided on the backing plate. The guiding block is in sliding or (through rollers or balls) rolling fit with the guide rail; alternatively, a groove that is open downward and inclined is provided on the lower edge of the sealing piece as the guide rail. The guiding block is adapted to the shape of the groove, and the guiding block is in sliding fit in the groove and can slide up and down relative to the groove. One side of the guiding block is connected to the backing plate; alternatively, a parallelogram cavity is formed on the sealing piece, and the guide rail is the two parallel and equal-length sides. The guiding block is also a parallelogram. The guiding block is installed inside the parallelogram cavity, and the two sides of the guiding block are in sliding fit with the two sides of the guide rail respectively. The height of the guiding block is less than the height of the parallelogram cavity, and one side of the guiding block is connected to the backing plate, so that the guiding block can slide along its side in the parallelogram cavity.

[0020] When a parallelogram cavity is formed on the sealing piece, the parallelogram cavity includes a parallel upper base and a lower base, and two parallel sides. Preferably, the upper base and the lower base of the parallelogram cavity are parallel to the horizontal plane, and the included angle between the two sides of the parallelogram cavity and the horizontal plane is not less than 10° and not greater than 70°. The upper base and the lower base of the corresponding guiding block are parallel to the horizontal plane, and the two sides of the guiding block are parallel and corresponding to the two sides of the parallelogram cavity.

[0021] The above-mentioned backing plate and the hot-end radial partition can be integrally or separately provided; when the backing plate and the hot-end radial partition are integrally provided, a section of the top of the hot-end radial partition is regarded as the backing plate.

[0022] As one of the preferred implementation solutions, the backing plate and the hot-end radial partition are separately provided, and the backing plate is located between the hot-end radial partition and the sealing piece; the two-dimensional guiding mechanism includes a driving block and a driven block. The driving block and the driven block are in contact with each other, and the contact surface is an inclined surface. The included angle between the inclined surface and the length direction of the sealing piece is 15-60°. The driving block is fixed on the backing plate, and the driven block is fixed on the sealing piece.

[0023] In order to improve the thermal deformation stability of the driving piece and the sealing piece, at least one roller is provided on the driving block or the driven block, and the driving block and the driven block are in contact in a rolling manner through the roller.

[0024] Preferably, the number of clamping bolts with the expansion starting end completely fixed is 1-5, and the number is less than the number of clamping bolts that are not fully tightened and fixed.

[0025] In order to improve the thermal deformation stability of the driving piece and the sealing piece, preferably, the mounting holes of the backing plate and the sealing piece corresponding to the clamping bolts that are not fully tightened and fixed are both elongated holes. The length direction of the mounting hole of the backing plate is consistent with the length direction of the sealing piece and the backing plate, and the length direction of the mounting hole of the sealing piece is perpendicular to the length direction of the sealing piece and the backing plate.

[0026] To ensure smooth relative expansion between the sealing piece and the backing plate, as well as stable deformation characteristics, the mounting hole of the sealing piece is a chamfered rectangle, and the width in the horizontal direction is not less than the sum of the expansion difference between the sealing piece and the backing plate at the corresponding position and the diameter of the clamping bolt; the mounting hole of the backing plate is a round hole or a waist-shaped hole in the horizontal direction, and the dimension of the mounting hole of the backing plate in the vertical direction is 0.2 - 5 mm larger than the diameter of the clamping bolt.

[0027] To improve the thermal deformation stability of the driving piece and the sealing piece, a spacer tube is also sleeved on the clamping bolt that is not fully tightened and fixed. The spacer tube passes through the mounting holes of the sealing piece and the backing plate at the same time, and both ends are respectively squeezed by the radial partition plate and the pressing plate at the heating end; the length of the spacer tube is 0.5 - 5 mm larger than the sum of the thicknesses of the sealing piece and the backing plate. The spacer tube is made of metal.

[0028] To improve the thermal deformation stability of the driving piece and the sealing piece, preferably, a 90° bend is provided on the upper edge of the backing plate to prevent the driving piece from being distorted and deformed along the length direction.

[0029] To obtain sufficient thermal compensation, preferably, the linear expansion coefficient of the sealing piece is more than 30% larger than that of the backing plate; or, the linear expansion coefficient of the backing plate is more than 30% larger than that of the sealing piece.

[0030] To ensure the stability of the deformation of the above-mentioned sealing device, preferably, no less than 2 sets of two-dimensional guiding mechanisms are provided between the sealing piece and the backing plate.

[0031] To reduce the influence of static friction on the deformation of the above-mentioned sealing device, preferably, more than two rollers are installed around the mounting hole of the sealing piece where the clamping bolt that is not fully tightened and fixed is located on the sealing piece.

[0032] To ensure the strength and stability of the above-mentioned sealing device, the thicknesses of the sealing piece, the backing plate, and the pressing plate are all not less than 3 mm, and the upper edge of the sealing piece is higher than the upper edges of the backing plate and the pressing plate.

[0033] The backing plate and the radial partition plate at the heating end can be integrally or separately arranged. For the convenience of installation and maintenance, preferably, the backing plate and the radial partition plate at the heating end are separately arranged, and the backing plate is located between the radial partition plate at the heating end and the sealing piece.

[0034] For each radial partition plate, the above-mentioned hot-end sealing device of the air preheater is an integral whole, and segmentation along the radial direction of the rotor is not allowed. However, for the convenience of processing and handling, a segmented structure is allowed to be welded on-site and then become an integral whole again.

[0035] The technologies not specifically defined in the present invention are all prior arts.

[0036] The hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate according to the present invention. The linear expansion coefficient of the sealing sheet is greater than that of the backing plate. When heated, they expand to different degrees. Meanwhile, combined with the setting of the two-dimensional guiding mechanism, the horizontal radial relative displacement is transformed into the vertical axial upward displacement, maximizing the compensation for the triangular air leakage area at the hot end of the air preheater, significantly reducing the air leakage rate of the air preheater, and ensuring the stability of operation. The deformation of the seal device and the mushroom-shaped deformation of the air preheater are both driven by heat, and the two deformation directions are opposite and synchronous, so as to keep the radial clearance at the hot end of the air preheater always maintained at a relatively small level. Further, the stability is improved, the malignant rubbing is avoided, and the service life of the sealing sheet is prolonged. Description of the Drawings

[0037] Figure 1 The front view of the hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate in Embodiment 1 of the present invention;

[0038] Figure 2 The side view of the hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate in Embodiment 1 of the present invention;

[0039] Figure 3 The front view of the hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate in Embodiment 2 of the present invention;

[0040] Figure 4 The side view of the hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate in Embodiment 2 of the present invention;

[0041] Figure 5 The side view of the hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate in Embodiment 3 of the present invention;

[0042] Figure 6 The schematic diagram of the two-dimensional guiding mechanism in Embodiment 4 of the present invention;

[0043] Figure 7 The schematic diagram of the two-dimensional guiding mechanism in Embodiment 5 of the present invention;

[0044] Figure 8 The schematic diagram of the two-dimensional guiding mechanism in Embodiment 7 of the present invention;

[0045] Figure 9 The front view of the hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate in Embodiment 8 of the present invention;

[0046] Figure 10 For Figure 9 The sectional view taken along line A-A in

[0047] Figure 11Schematic structural diagram of the two-dimensional guiding mechanism in Embodiment 9 of the present invention;

[0048] Figure 12 Schematic installation diagram of the non-fully fixed bolt assembly in Embodiment 10 of the present invention;

[0049] In the figure, 1 is a sealing piece, 11 is a sealing piece mounting hole, 2 is a backing plate, 21 is a backing plate mounting hole, 3 is a pressing plate, 4 is a clamping bolt, 41 is a bolt, 42 is a nut, 43 is a spacer tube, 44 is a roller, 5 is a hot-end radial partition, 6 is a two-dimensional guiding mechanism, 61 is a guide rail, 62 is a guiding block, 63 is a driving block, 64 is a driven block, 65 is a roller, 7 is a roller mechanism, M is the starting end of expansion, N is the rotor outer-edge angle steel; m is a fully fixed bolt assembly, n is a non-fully fixed bolt assembly; Detailed implementation manners

[0050] To better understand the present invention, the content of the present invention will be further clarified below in conjunction with embodiments. However, the content of the present invention is not limited to the following embodiments only.

[0051] The following "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0052] Embodiment 1

[0053] As Figure 1-2As shown in the figure, the hot-end seal device of the air preheater that compensates for the expansion difference between the sealing sheet and the backing plate is installed on the hot-end radial partition of the air preheater rotor. One end is close to the rotor center cylinder, and the other end is close to the rotor outer edge angle steel. It at least includes a backing plate, a sealing sheet, and a pressing plate arranged in sequence along the thickness direction. The sealing sheet is provided with sealing sheet mounting holes distributed along the length direction, and the backing plate is provided with backing plate mounting holes distributed along the length direction. The number of sealing sheet mounting holes and backing plate mounting holes is equal and they correspond one by one; the linear expansion coefficient of the sealing sheet is greater than that of the backing plate; the backing plate is separately arranged from the hot-end radial partition, and the backing plate is located between the hot-end radial partition and the sealing sheet. The backing plate is arranged along the length direction of the sealing sheet and is relatively fixed by clamping bolts that sequentially pass through the hot-end radial partition, the backing plate mounting holes, the sealing sheet mounting holes, and the pressing plate. Each pair of sealing sheet mounting holes and backing plate mounting holes corresponds to a clamping bolt; the end close to the rotor center cylinder is the expansion starting end. The first clamping bolt at the expansion starting end is completely tightened and fixed, and the rest of the clamping bolts are not completely tightened and fixed, so that the sealing sheet and the backing plate freely expand towards the other end close to the rotor outer edge angle steel after being heated; three groups of two-dimensional guiding mechanisms are arranged between the sealing sheet and the backing plate downstream of the expansion starting end. The two-dimensional guiding mechanism includes a guide rail and a guide block. The stroke of the guide rail is a straight line. The guide rail is arranged on the sealing sheet, and the guide block is arranged on the backing plate.

[0054] Verified by engineering practice, the expansion amount of the sealing sheet along the radial direction of the air preheater rotor is greater than that of the backing plate. Through the two-dimensional guiding mechanism, the horizontal radial relative displacement is transformed into a vertical axial upward displacement and at the same time a dislocation displacement is formed, which can effectively compensate for the triangular air leakage area at the hot end of the air preheater; and the deformation of the above-mentioned sealing device and the mushroom-shaped deformation of the air preheater are both driven by heat, and the two deformation directions are opposite and synchronous, so as to keep the radial clearance at the hot end of the air preheater always maintained at a relatively small level.

[0055] Embodiment 2

[0056] On the basis of Embodiment 1, the following further improvements are made: As Figure 3-4 shown, in order to prevent abnormal deformation of the above-mentioned sealing sheet from causing malignant rubbing with the air preheater sector plate, at least one set of roller mechanisms is installed at the upper edge of the sealing sheet, at the end close to the rotor outer edge angle steel. The vertex of the roller is not lower than the upper edge of the sealing sheet; once the sealing sheet rubs against the sector plate, the roller first contacts the sector plate, so as to ensure that the sealing sheet is not severely damaged. In order to reduce the influence of static friction on the deformation of the above-mentioned sealing device, more than two rollers are installed around the sealing sheet mounting holes where the clamping bolts that are not completely tightened and fixed are located on the sealing sheet.

[0057] Embodiment 3

[0058] On the basis of Embodiment 2, the following further improvements are made: As Figure 5 shown, the backing plate and the hot-end radial partition are integrally arranged.

[0059] Example 4

[0060] Based on Example 2, the following further improvements were made: As Figure 6 shown, the guide rail stroke is a curve, and the angle between the tangent of the curve and the horizontal plane is 45 - 60°; the guide rail is arranged at the lower edge of the sealing piece, and the guide block is arranged at the lower edge of the backing plate.

[0061] Example 5

[0062] Based on Example 2, the following further improvements were made: In order to obtain sufficient thermal compensation, the linear expansion coefficient of the sealing piece is more than 30% larger than that of the backing plate; in order to ensure the strength and stability of the above sealing device, the thicknesses of both the sealing piece and the backing plate are not less than 3 mm, and the upper edge of the sealing piece is higher than the upper edge of the backing plate. The two-dimensional guiding mechanism is as Figure 7 shown, the guide rail is arranged at the lower edge of the sealing piece and is a groove structure with an opening slanting downward and inclined, one side of the guide block is welded to the backing plate, the guide block is slidably connected in the groove, the guide block slides along the depth direction of the groove, the guide rail stroke is also the depth direction of the groove, and the angle between the guide rail stroke and the horizontal plane is about 60°. In this way, a 10-mm horizontal displacement can be converted into a 17.32-mm vertical upward displacement. When the sealing piece expands and contracts, the two-dimensional guiding mechanism plays a guiding role.

[0063] Example 6

[0064] Based on Example 5, the following further improvements were made: In order to ensure smooth relative expansion between the sealing piece and the backing plate and stable deformation characteristics, the mounting hole of the sealing piece is a chamfered rectangle, and the width in the horizontal direction is not less than the sum of the expansion difference between the sealing piece and the backing plate at the corresponding position and the diameter of the clamping bolt; the mounting hole of the backing plate is a round hole or a waist-shaped hole in the horizontal direction, and the dimension of the mounting hole of the backing plate in the vertical direction is 0.2 - 5 mm larger than the diameter of the clamping bolt.

[0065] Example 7

[0066] Based on Example 2, the following further improvements were made: As Figure 8 shown, a parallelogram cavity is opened on the sealing piece, and the guide rail is the two parallel and equal sides; a guide block is arranged inside the parallelogram cavity, and the guide block is also a parallelogram, and the guide block is welded to the backing plate. The two sides of the guide block are respectively slidably matched with the two sides of the guide rail. The height of the guide block is less than the height of the parallelogram cavity. The left and right sides of the guide block respectively play the roles of guiding during thermal expansion and guiding during cold contraction. The guide block can only slide up and down along the side edges inside the parallelogram cavity, and the upper bottom edge and the lower bottom edge of the parallelogram cavity play the roles of lower limit and upper limit.

[0067] Example 8

[0068] AsFigure 9 As shown, the hot-end sealing device of the air preheater that compensates for the expansion difference between the sealing plate and the backing plate is installed on the hot-end radial partition of the air preheater rotor. One end is close to the rotor central cylinder, and the other end is close to the rotor outer edge angle steel. It at least includes a backing plate, a sealing plate, and a pressing plate arranged in sequence along the thickness direction. The backing plate is separately arranged from the hot-end radial partition, and the backing plate is located between the hot-end radial partition and the sealing plate; the sealing plate is provided with sealing plate mounting holes distributed along the length direction, the backing plate is provided with backing plate mounting holes distributed along the length direction, and the linear expansion coefficient of the backing plate is greater than that of the sealing plate; the backing plate and the pressing plate are arranged along the length direction of the sealing plate and are relatively fixed by clamping bolts that simultaneously pass through the pressing plate, the sealing plate mounting holes, and the backing plate mounting holes; the end close to the rotor central cylinder is the expansion starting end, and the clamping bolts at the expansion starting end are completely tightened and fixed, and the remaining clamping bolts are not completely tightened and fixed, so that the sealing plate and the backing plate freely expand towards the other end close to the rotor outer edge angle steel after being heated; at least one set of two-dimensional guiding mechanisms is arranged between the sealing plate and the backing plate downstream of the expansion starting end.

[0069] Example 9

[0070] On the basis of Example 8, the following further improvements are made: As Figure 11 shown, the two-dimensional guiding mechanism includes a driving block and a driven block. The driving block and the driven block are in contact with each other, and the contact surface is an inclined surface. The angle between the inclined surface and the length direction of the sealing plate is about 50° (in practice, it can also be 30°, 40°, 60°, etc.). The driving block is fixed on the backing plate, and the driven block is fixed on the sealing plate. In order to improve the thermal deformation stability of the driving plate and the sealing plate, at least one roller is arranged on the driving block or the driven block, and the driving block and the driven block are in contact in a rolling manner with the roller.

[0071] Example 10

[0072] On the basis of Example 9, the following further improvements are made: The number of clamping bolts that are completely fixed at the expansion starting end is 2, and the number of clamping bolts that are not completely tightened and fixed is 4; in order to improve the thermal deformation stability of the driving plate and the sealing plate, as Figure 12 shown, the backing plate mounting holes and the sealing plate mounting holes corresponding to the clamping bolts that are not completely tightened and fixed are both long holes. The length direction of the backing plate mounting holes is the same as the length direction of the sealing plate and the backing plate, and the length direction of the sealing plate mounting holes is perpendicular to the length direction of the sealing plate and the backing plate. As Figure 10 and 12As shown in the figure, in order to improve the thermal deformation stability of the driving piece and the sealing piece, a spacer tube (304 stainless steel) is also sleeved on the clamping bolt that is not fully tightened and fixed. The spacer tube passes through the mounting holes of the sealing piece and the backing plate at the same time, and both ends are squeezed by the radial partition plate and the pressing plate at the heated end respectively; the length of the spacer tube is 2 mm larger than the total thickness of the sealing piece and the backing plate (in practice, it can also be 1 mm, 3 mm, 5 mm, etc.).

[0073] Example 11

[0074] On the basis of Example 10, the following further improvements are made: in order to improve the thermal deformation stability of the driving piece and the sealing piece, a 90° bend is provided on the backing plate to prevent the driving piece from being distorted along the length direction. In order to obtain sufficient thermal compensation, the linear expansion coefficient of the backing plate is more than 30% larger than that of the sealing piece.

[0075] Example 12

[0076] The difference from Example 1 is that: the installation sequence in Example 1 is the radial partition plate at the heated end, the backing plate, the sealing piece and the pressing plate in turn, while the installation sequence in this example is the radial partition plate at the heated end, the sealing piece, the backing plate and the pressing plate in turn.

[0077] Through practice, for the hot-end seal device of the air preheater that utilizes the expansion difference compensation between the sealing piece and the backing plate in the above examples, the linear expansion coefficient of the sealing piece is greater than that of the backing plate. The two expand to different degrees when heated. At the same time, combined with the setting of the two-dimensional guiding mechanism, the horizontal radial relative displacement is transformed into the vertical axial upward displacement, maximizing the compensation of the triangular air leakage area at the hot end of the air preheater, significantly reducing the air leakage rate of the air preheater; the deformation of the seal device and the mushroom-shaped deformation of the air preheater are both driven by heat, and the two deformation directions are opposite and synchronous, so as to keep the radial clearance at the hot end of the air preheater always maintained at a small level; further, the stability is improved, the malignant rubbing is avoided, and the service life of the sealing piece is extended.

Claims

1. An air preheater hot-end sealing device using differential expansion compensation between a sealing sheet and a backing plate is installed on the hot-end radial partition of the air preheater rotor, with one end close to the rotor central cylinder and the other end close to the rotor outer edge angle steel. It at least includes a sealing sheet and a backing plate arranged along the thickness direction. The sealing sheet is provided with sealing sheet mounting holes distributed along the length direction, and the backing plate is provided with backing plate mounting holes distributed along the length direction. It is characterized in that: The linear expansion coefficient of the sealing piece is different from that of the backing plate; the backing plate is arranged along the length direction of the sealing piece and is relatively fixed by clamping bolts that pass through the mounting holes of the sealing piece and the mounting holes of the backing plate at the same time; one end close to the rotor central cylinder is the expansion starting end, and the clamping bolts at the expansion starting end are fully tightened and fixed, and the remaining clamping bolts are not fully tightened and fixed, so that the sealing piece and the backing plate freely expand towards the other end close to the rotor outer edge angle steel after being heated; at least one set of two-dimensional guiding mechanisms is arranged between the sealing piece and the backing plate downstream of the expansion starting end; The two-dimensional guiding mechanism includes a guide rail and a guide block, the stroke of the guide rail is a straight line or a curve, and the included angle between the stroke of the guide rail or the tangent of the stroke of the guide rail and the horizontal plane is not less than 10° and not more than 70°; The linear expansion coefficient of the sealing piece is more than 30% larger than that of the backing plate; or, the linear expansion coefficient of the backing plate is more than 30% larger than that of the sealing piece.

2. The hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate as described in claim 1, characterized in that: It also includes a pressing plate, and the backing plate, the sealing piece and the pressing plate are relatively fixed in sequence along the thickness direction by clamping bolts.

3. The air preheater hot-end sealing device using differential expansion compensation between the sealing sheet and the backing plate as described in claim 1 or 2, characterized in that: At least one set of roller mechanisms is installed at one end of the upper edge of the sealing piece close to the rotor outer edge angle steel, and the vertex of the roller is not lower than the upper edge of the sealing piece.

4. The hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate as described in claim 1 or 2, characterized in that: The guide rail of the two-dimensional guiding mechanism is arranged on the sealing piece, and the guide block is arranged on the backing plate; a guide rail with an inclined plane structure is arranged on the sealing piece, and a guide block matching the guide rail is arranged on the backing plate, and the guide block is in sliding or rolling fit with the guide rail; Or, a groove with an opening downward and inclined is arranged on the lower edge of the sealing piece as the guide rail, the shape of the guide block is adapted to that of the groove, the guide block is slidably fitted in the groove and can slide up and down relative to the groove, and one side of the guide block is connected to the backing plate; Or, a parallelogram cavity is opened on the sealing piece, the guide rail is two parallel and equal-length sides, the guide block is also a parallelogram, the guide block is installed inside the parallelogram cavity, the two sides of the guide block are respectively in sliding fit with the two sides of the guide rail, the height of the guide block is less than the height of the parallelogram cavity, and one side of the guide block is connected to the backing plate.

5. The hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate as described in claim 1 or 2, characterized in that: The backing plate is separately arranged from the hot end radial partition plate, and the backing plate is located between the hot end radial partition plate and the sealing piece; the two-dimensional guiding mechanism includes a driving block and a driven block, the driving block and the driven block are in contact with each other, and the contact surface is an inclined plane, and the included angle between the inclined plane and the length direction of the sealing piece is 15-60°, the driving block is fixed on the backing plate, and the driven block is fixed on the sealing piece.

6. The hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate as claimed in claim 5, wherein: At least one roller is arranged on the driving block or the driven block, and the driving block and the driven block are in contact in a rolling manner of the roller.

7. The hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate as claimed in claim 1 or 2, characterized in that: The number of clamping bolts that are fully tightened and fixed at the expansion starting end is 1-5, and the number is less than the number of clamping bolts that are not fully tightened and fixed; the mounting holes of the backing plate and the mounting holes of the sealing piece corresponding to the clamping bolts that are not fully tightened and fixed are both oblong holes, the length direction of the mounting holes of the backing plate is consistent with the length direction of the sealing piece and the backing plate, and the length direction of the mounting holes of the sealing piece is perpendicular to the length direction of the sealing piece and the backing plate.

8. The hot-end seal device of the air preheater using differential expansion compensation between the sealing sheet and the backing plate as described in claim 7, characterized in that: The width of the sealing piece mounting hole in the horizontal direction is not less than the sum of the expansion difference between the sealing piece and the backing plate at the corresponding position and the diameter of the clamping bolt; the mounting hole of the backing plate is a round hole or a waist hole in the horizontal direction, and the dimension of the mounting hole of the backing plate in the vertical direction is 0.2-5 mm larger than the diameter of the clamping bolt.

9. The hot-end seal device of the air preheater using the expansion difference compensation between the sealing sheet and the backing plate as claimed in claim 1 or 2, characterized in that: A spacer tube is also sleeved on the clamping bolt that is not fully tightened and fixed. The spacer tube passes through the mounting holes of the sealing sheet and the backing plate at the same time, and both ends are respectively squeezed by the hot-end radial partition plate and the pressing plate; the length of the spacer tube is 0.5 - 5 mm larger than the total thickness of the sealing sheet and the backing plate.

10. The hot-end seal device of the air preheater using the expansion difference compensation between the sealing sheet and the backing plate as claimed in claim 1 or 2, characterized in that: No less than two groups of two-dimensional guiding mechanisms are arranged between the sealing sheet and the backing plate.

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