Bimetal thermal compensation sealing device of air pre-heater

Abstract

The utility model discloses a bimetal thermal compensation sealing device of an air pre-heater, which is mounted on a radial partition plate at the hot end of a rotor of the air pre-heater and at least comprises a driving plate, a sealing fin and a 7-shaped transposition mechanism, the driving plate and the sealing piece are installed on the hot end radial partition plate through clamping bolts, in the radial direction, one end of the driving plate and one end of the sealing piece are completely fixed to serve as a fixed end, the other end has movement allowance to serve as a free end, and expansion coefficients of the driving plate and the sealing piece are different. The 7-shaped transposition mechanism comprises a 7-shaped driving arm, a transposition mechanism fixing block and a central pin shaft; the transposition mechanism fixing block is installed on the hot end radial partition plate, the 7-shaped driving arm is connected with the transposition mechanism fixing block through the center pin shaft, and the 7-shaped driving arm can rotate around the center pin shaft; a transverse sliding groove is formed in the sealing piece, a longitudinal sliding groove is formed in the driving plate, and the 7-shaped driving arm is in sliding fit with the transverse sliding groove and the longitudinal sliding groove at the same time. The device can realize dynamic compensation according to dynamic changes of cold and hot states of an air leakage area, and is accurate and stable.

Description

Technical Field

[0001] The utility model relates to a bimetallic thermal compensation sealing device for an air preheater, belonging to the technical field of sealing. Background Art

[0002] The rotary 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 deforms into a "mushroom-shaped" shape due to the different temperatures of the upper and lower end surfaces and the weakening of the rigidity of the steel after being heated. The traditional rigid sealing plate is fixed to the rotor partition in sections by bolts. As the rotor partition deforms, the air leakage gap also changes. Based on the mechanism of the "mushroom-shaped" deformation of the rotor, appropriate cold clearances are reserved at the axial and cold end radial positions, and the dynamic and static clearances tend to zero in the hot state; although the cold clearance reserved at the hot end radial position is very small, a larger triangular air leakage area will be formed in the hot state.

[0003] In order to reduce the area of ​​the above-mentioned triangular 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. It is not difficult to understand that 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 sealing sheet automatically sticks to the fan plate and the fan plate automatically tracks the sealing sheet to achieve the purpose of reducing air leakage. However, both 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, the world's leading supplier of rotary air preheaters, has not equipped LCS on the air preheater, 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, which cannot meet the engineering requirements at all.

[0004] The air leakage problem in the radial triangular air leakage area at the hot end has not been well solved. Moreover, as the units develop towards large capacity, the diameter of the air preheater rotor continues to increase. If no measures are taken, the air leakage share in the radial triangular air leakage area at the hot end will become larger and larger. If a traditional rigid sealing plate is used and the hot end fan plate is not adjustable, the radial outermost gap at the hot end of a 300MW unit exceeds 10mm, the 600MW unit exceeds 25mm, and the gap of a 1000MW unit is about 50mm. The radial triangular 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%.

[0005] Chinese Patent 202220233086.2 discloses an air preheater hot end sealing device that utilizes the expansion difference compensation between the sealing plate and the pad. The horizontal expansion difference between the sealing plate and the pad is converted into a vertical sealing gap compensation amount by a two-dimensional guiding mechanism. However, the two-dimensional guiding mechanism given in the embodiment is adversely affected by sliding friction. Generally, the vertical gap compensation amount obtained is smaller than the horizontal expansion difference between the sealing plate and the pad, which is not conducive to achieving a larger gap compensation amount. Summary of the invention

[0006] The utility model provides a bimetallic heat compensation sealing device for an air preheater, which is used to eliminate the radial triangular air leakage area at the hot end of the air preheater caused by heating, compensate the radial gap at the hot end, and has a large compensation amount, which significantly reduces the air leakage rate of the air preheater.

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

[0008] An air preheater bimetallic heat compensation sealing device is installed on the radial partition plate at the hot end of the air preheater rotor, and at least includes a driving plate, a sealing plate and a 7-shaped transposition mechanism;

[0009] The driving plate and the sealing sheet are installed on the hot end radial partition plate through clamping bolts. In the radial direction, one end of the driving plate and the sealing sheet is completely fixed as the fixed end, and the other end has a movable margin as the free end. The expansion coefficients of the driving plate and the sealing sheet are different;

[0010] The 7-shaped transposition mechanism at least includes a 7-shaped driving arm, a transposition mechanism fixing block and a center pin shaft; the transposition mechanism fixing block is installed on the hot end radial partition, the 7-shaped driving arm is connected to the transposition mechanism fixing block through the center pin shaft, and the 7-shaped driving arm can rotate around the center pin shaft; a transverse slide groove is provided on the sealing plate, a longitudinal slide groove is provided on the driving plate, and the 7-shaped driving arm slides with the transverse slide groove and the longitudinal slide groove at the same time.

[0011] The expansion coefficients of the driving plate and the sealing sheet are different. When heated, due to the different expansion degrees of the two, the driving plate and the sealing sheet will be misaligned under the force of the expansion difference, thereby compensating the radial clearance of the hot end. The setting of the 7-shaped transposition mechanism allows the sealing sheet and the driving plate to slide along a specific path when expanding or contracting, which can not only ensure the stability of operation, but also accurately control the displacement, and then accurately control the compensation amount, effectively reducing the air leakage rate of the air preheater while ensuring the safe and stable operation of the air preheater.

[0012] The above radial direction is consistent with the radial direction of the air preheater rotor.

[0013] In order to increase the compensation amount, the above-mentioned 7-shaped driving arm is composed of an active arm and a driven arm connected as one body, the active arm slides with the transverse slide groove, the driven arm slides with the longitudinal slide groove, and the length of the active arm is greater than that of the driven arm, so that the gap compensation amount can be enlarged. The specific length of the active arm is determined according to the amount of compensation required in practice.

[0014] In order to ensure the timeliness of compensation response, one end of the active arm slides with the horizontal slide groove, and the other end is vertically connected to the driven arm to form a 7-shaped driving arm. The center pin is located at the connection between the active arm and the driven arm. When heated and expanded, the 7-shaped driving arm will be driven to rotate around the center pin under the action of the expansion difference, so that the driving plate and the sealing sheet will be misaligned along a specific path to compensate for the radial clearance of the hot end. When cooled, it will shrink in the opposite direction along the specific path to restore the misalignment.

[0015] In order to further improve the stability and timeliness of compensation, one end of the active arm slides with the transverse slide groove through a convex point. That is, a convex point is set at one end of the active arm, and the convex point slides in the transverse slide groove. When the 7-shaped driving arm is selected under the action of the expansion difference, the convex point slides in the transverse slide groove and controls the path and amplitude of the upward expansion of the sealing sheet.

[0016] In order to improve the stability of operation, the bottom of the driven arm is in an arc shape that matches the longitudinal slide groove. When the 7-shaped driving arm rotates around the center pin, the bottom of the driven arm slides along the longitudinal slide groove.

[0017] The linear expansion coefficient of the driving plate is greater than that of the sealing plate. In this way, the expansion of the sealing plate along the radial direction of the air preheater rotor is greater than that of the pad. The radial relative displacement is converted into a vertical axial upward displacement through the 7-shaped transposition mechanism, and the sealing plate moves upward to form a dislocation displacement with the driving plate, which can effectively compensate for the triangular air leakage area at the hot end of the air preheater. The deformation of the sealing device and the mushroom-shaped deformation of the air preheater are both driven by heat, and the deformation directions of the two 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.

[0018] The above-mentioned drive plate is arranged along the length direction of the sealing plate; the fixed ends of the drive plate and the sealing plate are close to the rotor center tube, and the free ends are close to the rotor outer edge angle steel; the end close to the rotor center tube (fixed end) is also called the expansion starting end, the clamping bolts at the expansion starting end are tightened and fixed (completely fixed, without any movable margin), and the remaining clamping bolts are not completely tightened and have movable margin, so that the drive plate and the sealing plate can expand freely toward the free ends close to the rotor outer edge angle steel after being heated.

[0019] That is, during installation, the bolts are installed through the mounting holes on the hot end radial partition, the drive plate and the sealing sheet at the same time, and are relatively fixed by nuts, some nuts are tightened, and some nuts are not completely tightened, so as to facilitate the relative expansion and dislocation of the drive plate and the sealing sheet to compensate for the gap. If the nuts are completely tightened, the corresponding bolts are tightened and fixed. At this time, the drive plate and the sealing sheet cannot move relative to each other; if the nuts are not completely tightened, the corresponding bolts are not completely tightened, that is, there is a margin of movement between the drive plate and the sealing sheet and the clamping bolts, and the drive plate and the sealing sheet can move relative to each other within the margin of movement.

[0020] As one of the preferred implementation schemes, the mounting holes on the drive plate and the sealing plate corresponding to the clamping bolts that are not fully tightened are both waist-shaped holes, wherein the waist-shaped holes on the drive plate are arranged horizontally, and the waist-shaped holes on the sealing plate are arranged longitudinally.

[0021] In order to ensure the compensation effect, at least one set of 7-shaped transposition mechanisms is arranged downstream of the above-mentioned expansion starting end, and the specific number can be determined according to the on-site conditions.

[0022] The driving plate and the sealing plate are mounted on the same side of the hot end radial partition plate through clamping bolts.

[0023] Technologies not specifically limited in the present invention are all prior art.

[0024] The utility model relates to a bimetallic thermal compensation sealing device for an air preheater, which can realize dynamic compensation according to the dynamic changes of the hot and cold states in the air leakage area, and does not need to set up an LCS, has low cost and stable operation; the setting of a 7-shaped transposition mechanism improves the accuracy of compensation control and increases the compensation amount, has a simple and stable structure, and is conducive to engineering promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a front view of the bimetallic heat compensation sealing device of the air preheater of the utility model;

[0026] Figure 2 for Figure 1 Middle AA view to the left;

[0027] Figure 3 for Figure 1 Middle BB right view;

[0028] Figure 4 for Figure 1 Rear view of

[0029] Figure 5 It is a three-dimensional diagram of the bimetallic heat compensation sealing device of the air preheater of the utility model;

[0030] Figure 6This is a diagram showing the change from cold state to hot state of the bimetallic heat compensation sealing device of the air preheater of the utility model (from left to right, the initial, middle and final states respectively);

[0031] Figure 7 This is a front view of a 7-shaped transposition mechanism of the utility model;

[0032] Figure 8 The utility model is a three-dimensional diagram of a 7-shaped transposition mechanism;

[0033] In the figure, 1 is a driving plate, 11 is a longitudinal slide groove, 2 is a sealing plate, 21 is a transverse slide groove, 3 is a 7-shaped transposition mechanism, 31 is a 7-shaped driving arm, 311 is an active arm, 312 is a driven arm, 313 is a protrusion, 32 is a transposition mechanism fixing block, 33 is a center pin shaft, M is an expansion starting end, N is a rotor outer edge angle steel; m is a completely fixed bolt assembly, and n is a non-completely fixed bolt assembly. DETAILED DESCRIPTION

[0034] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with embodiments, but the content of the present invention is not limited to the following embodiments.

[0035] The directions or positional relationships indicated by the following “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, etc. are based on the relative directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0036] Example 1

[0037] like Figure 1-5As shown, a bimetallic thermal compensation sealing device for an air preheater is installed on the radial partition of the hot end of the air preheater rotor, and at least includes a driving plate, a sealing plate and a 7-shaped transposition mechanism; the driving plate and the sealing plate are installed on the radial partition of the hot end by clamping bolts, and the driving plate and the sealing plate are located on the same side of the radial partition of the hot end, and radially, one end of the driving plate and the sealing plate is completely fixed as a fixed end, and the other end has a movable margin as a free end, and the expansion coefficients of the driving plate and the sealing plate are different; the 7-shaped transposition mechanism at least includes a 7-shaped driving arm, a transposition mechanism fixing block and a center pin; the transposition mechanism fixing block is installed on the radial partition of the hot end by bolts, the 7-shaped driving arm is connected to the transposition mechanism fixing block by the center pin, and the 7-shaped driving arm can rotate around the center pin; a transverse slide groove is provided on the sealing plate, and a longitudinal slide groove is provided on the driving plate, and the 7-shaped driving arm slides with the transverse slide groove and the longitudinal slide groove at the same time, that is, the 7-shaped driving arm is located between the driving plate and the sealing plate.

[0038] The expansion coefficients of the drive plate and the sealing sheet are different. When heated, due to the different expansion degrees of the two, the drive plate and the sealing sheet will be misaligned under the force of the expansion difference, thereby compensating the radial clearance of the hot end. Figure 6 As shown, the setting of the 7-shaped transposition mechanism allows the sealing plate and the driving plate to slide along a specific path when expanding or contracting, which can not only ensure the stability of operation, but also accurately control the displacement, and then accurately control the compensation amount, while effectively reducing the air leakage rate of the air preheater, ensuring the safe and stable operation of the air preheater.

[0039] Example 2

[0040] On the basis of Example 1, the following improvements were made: Figure 7-8 As shown, in order to increase the compensation amount, the above-mentioned 7-shaped driving arm is composed of an active arm and a driven arm which are connected as one body. The active arm slides in cooperation with the transverse slide groove, and the driven arm slides in cooperation with the longitudinal slide groove. The length of the active arm is greater than that of the driven arm, so that the gap compensation amount can be amplified.

[0041] Example 3

[0042] On the basis of Example 2, the following improvements were made: Figure 5-8 As shown, in order to ensure the timeliness of the compensation response, one end of the active arm slides with the horizontal slide groove through a convex point, and the other end is vertically connected to the driven arm to form a 7-shaped driving arm, and the center pin is located at the connection between the active arm and the driven arm. When heated and expanded, under the action of the expansion difference, the 7-shaped driving arm will be driven to rotate around the center pin, thereby causing the driving plate and the sealing plate to be misaligned along a specific path to compensate for the radial clearance of the hot end. When cooled, they will shrink in the opposite direction along a specific path to restore the misalignment. In order to improve the stability of operation, the bottom of the driven arm is an arc that matches the longitudinal slide groove. When the 7-shaped driving arm rotates around the center pin, the bottom of the driven arm slides along the longitudinal slide groove.

[0043] Example 4

[0044] On the basis of Example 3, the following improvements were made: Figure 1 As shown, the linear expansion coefficient of the drive plate is greater than that of the sealing sheet, and the drive plate is arranged along the length direction of the sealing sheet; the fixed ends of the drive plate and the sealing sheet are close to the rotor center tube, and the free ends are close to the rotor outer edge angle steel; the clamping bolts at the fixed ends are tightened and fixed, and the remaining clamping bolts are not completely tightened to leave a margin of activity, so that the drive plate and the sealing sheet can expand freely toward the free ends close to the rotor outer edge angle steel after being heated. The mounting holes on the drive plate and the sealing sheet corresponding to the incomplete tightening of the clamping bolts are both waist-shaped holes, wherein the waist-shaped holes on the drive plate are arranged horizontally, and the waist-shaped holes on the sealing sheet are arranged longitudinally. In order to ensure the compensation effect, at least one set of 7-shaped transposition mechanisms is arranged downstream of the expansion starting end.

[0045] It has been verified in practice that the bimetallic thermal compensation sealing device of the air preheater in the above-mentioned examples can realize dynamic compensation according to the dynamic changes of the cold and hot states of the air leakage area, and there is no need to set up LCS, with low cost and stable operation; the setting of the 7-shaped transposition mechanism improves the accuracy of compensation control, increases the compensation amount, and has a simple and stable structure, which is conducive to engineering promotion.

Claims

1. A bimetallic heat compensation seal device for an air preheater, installed on the radial partition plate at the hot end of the air preheater rotor, characterized in that: It at least comprises a driving plate (1), a sealing plate (2) and a 7-shaped transfer mechanism (3); The drive plate (1) and the sealing plate (2) are mounted on the hot end radial partition plate by means of clamping bolts. In the radial direction, one end of the drive plate (1) and the sealing plate (2) is completely fixed as a fixed end, and the other end has a movable margin as a free end. The expansion coefficients of the drive plate (1) and the sealing plate (2) are different. The 7-shaped transfer mechanism (3) at least comprises a 7-shaped drive arm (31), a transfer mechanism fixing block (32) and a center pin (33); the transfer mechanism fixing block (32) is mounted on a hot end radial partition plate, the 7-shaped drive arm (31) is connected to the transfer mechanism fixing block (32) via the center pin (33), and the 7-shaped drive arm (31) can rotate around the center pin (33); a transverse slide groove (21) is provided on the sealing plate (2), a longitudinal slide groove (11) is provided on the drive plate (1), and the 7-shaped drive arm (31) is slidably matched with the transverse slide groove (21) and the longitudinal slide groove (11) at the same time.

2. The air preheater bimetallic thermal compensation sealing device according to claim 1, characterized in that: The 7-shaped driving arm (31) is composed of an active arm (311) and a driven arm (312) which are connected as one body. The active arm (311) is slidably matched with the transverse slide groove (21), and the driven arm (312) is slidably matched with the longitudinal slide groove (11). The length of the active arm (311) is greater than that of the driven arm (312).

3. The air preheater bimetallic thermal compensation sealing device according to claim 2, characterized in that: One end of the active arm (311) is slidably matched with the transverse slide groove (21), and the other end is vertically connected with the driven arm (312) to form a 7-shaped driving arm (31), and the center pin (33) is located at the connection between the active arm (311) and the driven arm (312).

4. The air preheater bimetallic thermal compensation sealing device according to claim 2 or 3, characterized in that: One end of the active arm (311) is slidably matched with the transverse sliding groove (21) via a convex point (313).

5. The bimetallic thermal compensation sealing device for air preheater according to claim 2 or 3, characterized in that: The bottom of the driven arm (312) is arc-shaped. When the 7-shaped driving arm (31) rotates around the central pin (33), the bottom of the driven arm (312) slides along the longitudinal slide groove (11).

6. The air preheater bimetallic thermal compensation sealing device according to any one of claims 1 to 3, characterized in that: The linear expansion coefficient of the driving plate (1) is greater than the linear expansion coefficient of the sealing plate (2).

7. The air preheater bimetallic thermal compensation sealing device according to any one of claims 1 to 3, characterized in that: The drive plate (1) is arranged along the length direction of the sealing plate (2); the fixed ends of the drive plate (1) and the sealing plate (2) are close to the rotor center tube, and the free ends are close to the rotor outer edge angle steel; the clamping bolts at the fixed ends are tightened and fixed, and the remaining clamping bolts are not completely tightened to leave a movable margin, so that the drive plate and the sealing plate (2) can expand freely towards the free ends close to the rotor outer edge angle steel after being heated.

8. The bimetallic thermal compensation sealing device for air preheater according to claim 7, characterized in that: The mounting holes on the drive plate (1) and the sealing plate (2) corresponding to the clamping bolts that are not fully tightened are both waist-shaped holes, wherein the waist-shaped holes on the drive plate (1) are arranged horizontally, and the waist-shaped holes on the sealing plate (2) are arranged longitudinally.

9. The bimetallic thermal compensation sealing device for air preheater according to claim 7, characterized in that: At least one set of 7-shaped transposition mechanisms (3) is arranged downstream of the expansion starting end.

10. The air preheater bimetallic thermal compensation sealing device according to any one of claims 1 to 3, characterized in that: The driving plate (1) and the sealing plate (2) are mounted on the same side of the hot end radial partition plate through clamping bolts.

Images