Air preheater multi-sheet sealing structure with elastic sheets easy to replace and elastic sheet replacing method

Abstract

The invention discloses an air preheater multi-sheet sealing structure with elastic sheets easy to replace and a replacement method of the elastic sheets. The sealing structure comprises the elastic sheets and a basic thick sheet which are overlapped in the thickness direction. Each of the elastic thin sheet and the basic thick sheet is in a long strip shape formed by splicing more than two elastic thin sheet sections and basic thick sheet sections along the length direction; the length of the elastic sheet section is not greater than 2 / 3 of the length of the corresponding basic thick section; more than two positioning bosses are arranged on the elastic sheet section; more than four positioning concave holes are formed in the basic thick segment; the positioning boss and the positioning concave hole can be freely matched; and the positioning bosses on the elastic thin sheet section are movably matched in the positioning concave holes in the basic thick sheet section. The elastic sheet section and the basic thick sheet section are fixed in relative positions through matching of the positioning bosses and the positioning concave holes, when the elastic sheet is damaged by abrasion, blowing damage and the like, the elastic sheet can be locally damaged and locally replaced, repositioning is not needed, and cost is saved.

Description

Technical Field

[0001] The present invention belongs to the field of seals for Junk air preheaters, and relates to a multi-piece seal structure for an air preheater that is easy to replace elastic sheets and a method for replacing the elastic sheets. Background Art

[0002] The Junk air preheater (hereinafter referred to as "air preheater") is a heat exchange device used in large power plant boilers. It uses the heat of boiler flue gas to heat the air required for combustion. The rotor of the air preheater consists of a large number of heat storage elements. When the rotor rotates slowly, the flue gas and air flow through the rotor alternately in the reverse direction. The heat storage elements absorb heat on the flue gas side and release heat on the air side, thereby achieving the preheating effect of reducing the boiler flue gas discharge temperature and increasing the hot air temperature, and improving the economy of the power plant.

[0003] The rotor of the air preheater is actually a huge cylinder. When the rotor 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. Therefore, when installing in the cold state, a gap needs to be reserved between the rotor of the air preheater and the stator. The size of the reserved gap depends on the deformation amount of each component of the air preheater, especially the deformation amount of the rotor of the air preheater. In principle, it is necessary to ensure that the rotor and the stator of the air preheater do not rub against each other under any working conditions to prevent the rotor from being stuck and causing safety accidents.

[0004] Since the air side pressure of the air preheater is higher than the flue gas side pressure, a sealing device is required to reduce the leakage of air to the flue gas side to reduce energy loss. The conventional practice in engineering is to install sealing sheets on the rotor partition. The sealing sheets and the rotor partition are connected by bolts. The rotor partition is generally relatively long, and the shorter sealing sheets are connected end to end to form a complete seal. The traditional sealing sheet is a straight sheet type. When installing, a relatively large sealing gap and a relatively small sealing sheet thickness need to be reserved to ensure the safe and stable operation of the air preheater.

[0005] In engineering applications, some problems have emerged with traditional sealing sheets: ① If the reserved gap of the traditional sealing sheet is too small, it may cause the rotor of the air preheater to jam. If the reserved gap is too large, the leakage will increase. In engineering, often only a compromise can be made between the two; ② The traditional sealing sheet is relatively thin, and it is prone to distortion and deformation at high temperatures, expanding the sealing gap; ③ The high-temperature flue gas contains coal ash, which continuously erodes the sealing sheet under the drive of high-speed air flow. Coupled with the influence of corrosion, the gap between the traditional sealing sheet and the sealing surface will continuously expand; ④ In order to balance the running-in characteristics of the sealing sheet and the sealing surface and ensure that the air leakage rate does not become too large during long-term use, sometimes the sealing sheet is set as a multi-piece sealing structure, which at least includes an elastic thin sheet and a basic thick sheet welded together. The gap between the elastic thin sheet and the sealing surface is smaller than the gap between the basic thick sheet and the sealing surface to ensure that even if there is rubbing, it is the elastic thin sheet that rubs against the sealing surface first. Since the above-mentioned elastic thin sheet and the basic thick sheet are welded together, once the elastic thin sheet shows problems such as wear and erosion, the basic thick sheet needs to be replaced together, and re-installation and positioning are required, resulting in relatively high replacement and maintenance costs. Summary of the Invention

[0006] The object of the present invention is to provide a multi-piece sealing structure for an air preheater that is easy to replace the elastic thin sheet and a method for replacing the elastic thin sheet, overcoming the technical problems such as the difficulty in replacing the existing elastic thin sheet and the high cost.

[0007] To solve the above technical problems, the technical solution of the present invention is:

[0008] A multi-piece sealing structure for an air preheater that is easy to replace the elastic thin sheet, including at least one elastic thin sheet and at least one basic thick sheet laminated in the thickness direction (that is, the elastic thin sheet and the basic thick sheet are laminated together in the thickness direction). The thickness of each elastic thin sheet is between 0.8 - 1.6 mm, and the thickness of each basic thick sheet is between 2 - 10 mm; its characteristics are:

[0009] The elastic thin sheet is a strip-shaped one formed by splicing two or more elastic thin segments along the length direction; the basic thick sheet is a strip-shaped one formed by splicing one or more basic thick segments along the length direction;

[0010] Two or more elastic thin segments are covered along the length direction on the same basic thick segment, and the length of each elastic thin segment is not greater than 2 / 3 of the length of the basic thick segment where it is located; two or more positioning bosses are provided on each elastic thin segment, and the height of the positioning boss is at least 2 mm; four or more positioning concave holes are provided on each basic thick segment, and the recessed depth of the positioning concave hole is at least 2 mm; the positioning boss and the positioning concave hole can be freely matched, that is, any positioning boss can be matched in any positioning concave hole; the positioning bosses on each elastic thin segment are movably fitted in the positioning concave holes on the basic thick segment where they are located;

[0011] One end of each elastic thin segment and each basic thick segment in the width direction is a fixed end, and the other end is a free end. Waist-shaped mounting holes are provided at the fixed ends of each elastic thin segment and each basic thick segment, and the waist-shaped mounting holes on each elastic thin segment are aligned with the waist-shaped mounting holes on the corresponding basic thick segment.

[0012] Each basic thick segment and the corresponding elastic thin segment are installed on the radial partition of the air preheater rotor through mounting bolts that simultaneously pass through the waist-shaped mounting holes of both (the elastic thin segment and the basic thick segment), and the free end of the elastic thin segment extends beyond the free end of the basic thick segment.

[0013] The applicant has found through research that when using the above multi-piece seal structure of the air preheater, after the elastic thin sheet has problems such as wear and blow damage, the elastic thin sheet can be replaced separately in segments. Only the mounting bolts in the waist-shaped mounting holes of the corresponding segment need to be removed. Since the length of the elastic thin segment is not greater than 2 / 3 of the length of the corresponding basic thick segment, removing the mounting bolts in the waist-shaped mounting holes of one elastic thin segment will not cause the installation position of the basic thick segment to change. The relative position between the elastic thin segment and the basic thick segment is fixed through the cooperation relationship of the positioning boss and the positioning concave hole, so as to ensure that the seal does not need to be reinstalled and positioned as a whole, saving replacement and maintenance costs.

[0014] The above-mentioned lamination of the elastic thin sheet and the basic thick sheet in the thickness direction overcomes or alleviates the problem of the seal gap expansion caused by the easy twisting deformation and corrosion of the seal in a high-temperature environment. The free end of the elastic thin segment extends beyond the free end of the basic thick segment. In this way, during operation, a smaller seal gap can be reserved, and even if there is rubbing, it is not easy to cause the air preheater rotor to get stuck, and the elastic thin segment shows problems such as wear and blow damage first. By adopting the technical solution of the present application, only the elastic thin sheet can be replaced, and only local damage needs to be replaced locally, which is convenient, safe, reliable, and low-cost.

[0015] The elastic thin segment and the corresponding basic thick segment are in a corresponding relationship, that is, the basic thick segment and the elastic thin segment covering this basic thick segment are in a corresponding relationship.

[0016] In order to improve the installation stability, at least two waist-shaped mounting holes are provided at the fixed ends of each elastic thin segment and each basic thick segment. This can avoid the uncontrollable torsion of the elastic thin segment during operation.

[0017] In order to save costs and facilitate installation control, the number of waist-shaped mounting holes in the basic thick segment is equal to the total number of waist-shaped mounting holes on all elastic thin segments covering this basic thick segment, and they correspond one by one.

[0018] In order to balance costs and stability, the number of positioning concave holes in the basic thick segment is equal to the total number of positioning bosses on all elastic thin segments covering this basic thick segment, and they correspond one by one.

[0019] For ease of disassembly and assembly, preferably, the positioning boss is circular ring-shaped, the positioning concave hole is waist-shaped, and the length direction of the positioning concave hole (waist-shaped) is consistent with the length direction of the base thick sheet.

[0020] For convenience of preparation and for the free matching of the positioning boss and the positioning concave hole, the shapes and sizes of all the positioning bosses are the same, and the shapes and sizes of all the positioning concave holes are the same.

[0021] For convenience of fabrication and installation, further preferably, the width of the positioning concave hole is 0.2 - 1 mm larger than the diameter of the positioning boss, and the length of the positioning concave hole is 2 - 10 mm larger than the diameter of the positioning boss.

[0022] For improving the overall sealing performance, further preferably, the height of the positioning boss is not greater than the recess depth of the positioning concave hole.

[0023] For convenience of machining and fabrication, preferably, the positioning concave hole is a through hole.

[0024] For improving the overall sealing performance, preferably, the positioning concave hole is a blind hole.

[0025] To ensure the overall sealing performance of the device, elastic thin segments are distributed along the length direction on each of the base thick segments. That is, the sum of the lengths of the elastic thin segments on the same base thick segment is equal to the length of the base thick segment where they are located. In the width direction, the free end of the elastic thin segment extends beyond the free end of the base thick segment.

[0026] For convenience of fabrication and disassembly and maintenance, the lengths of the elastic thin segments on the same base thick segment are equal, and the length of the base thick segment is an integer multiple of the length of the corresponding elastic thin segment.

[0027] Further preferably, the lengths of all the base thick segments are equal, and the lengths of all the elastic thin segments are also equal. This is convenient for preparation, storage and recording, and also convenient for disassembly, replacement.

[0028] For convenience of preparation and to ensure the stability in use, the positioning boss is welded on the elastic thin sheet.

[0029] A method for replacing the elastic thin sheet of a multi-piece sealing structure of an air preheater, using the above-mentioned multi-piece sealing structure of the air preheater that is easy to replace the elastic thin sheet. When the elastic thin sheet is damaged, determine the damaged elastic thin segment, remove the mounting bolt in the waist-shaped mounting hole corresponding to the damaged elastic thin segment, and replace the elastic thin segment;

[0030] If there are more than two damaged elastic thin segments on the same base thick segment, they shall be replaced one by one (that is, after replacing one elastic thin segment, then remove and replace the next one). Since the length of the elastic thin segment is not greater than 2 / 3 of the length of the base thick segment where it is located, remove the installation bolts of the waist-shaped installation holes corresponding to one elastic thin segment. The remaining installation bolts on the base thick segment cooperate with the positioning convex platform and positioning concave holes, and will not cause the change of the installation position of the base thick segment, so there is no need to reinstall and position the whole;

[0031] The elastic thin segments not on the same base thick segment can be replaced simultaneously or one by one.

[0032] The technologies not mentioned in the present invention are all prior arts.

[0033] The multi-piece sealing structure of the air preheater with elastic thin sheets that is easy to replace in the present invention realizes the relative position fixation through the matching of the positioning convex platform and positioning concave holes between the elastic thin segments and the base thick segments. When there are damage problems such as wear and blow damage on the elastic thin sheets, the elastic thin sheets can be replaced separately by segments, and only the installation bolts in the corresponding waist-shaped installation holes need to be removed. Since the length of the elastic thin segment is not greater than 2 / 3 of the length of the base thick segment where it is located, removing the installation bolts of the waist-shaped installation holes corresponding to one elastic thin segment will not cause the change of the installation position of the base thick segment. Therefore, when replacing the elastic thin segment, there is no need to reposition, which saves the disassembly, installation and maintenance costs, and has a simple and stable structure and is simple and convenient for disassembly and installation. Brief Description of the Drawings

[0034] Figure 1 is an exploded view of one segment of the multi-piece sealing structure of the air preheater with elastic thin sheets that is easy to replace in the present invention;

[0035] Figure 2 is the front view of one segment of the multi-piece sealing structure of the air preheater with elastic thin sheets that is easy to replace in the present invention;

[0036] Figure 3 is Figure 2 the side view;

[0037] Figure 4 is the front view of the elastic thin segment in the present invention;

[0038] Figure 5 is Figure 4 the side view.

[0039] In the figure, 1 is the base thick segment, 1-1 is the positioning concave hole, 1-2 is the waist-shaped installation hole on the base thick segment, 2 is the elastic thin segment, 2-1 is the positioning convex platform, and 2-2 is the waist-shaped installation hole on the elastic thin segment. Detailed Embodiment

[0040] The present invention is described in detail below with reference to specific embodiments.

[0041] Example 1

[0042] like Figures 1-4 As shown, a multi-piece sealing structure of an air preheater with easily replaceable elastic sheets comprises an elastic sheet and a basic thick sheet stacked together in the thickness direction, the thickness of the elastic sheet is 1 mm (proven in practice, the values ​​may also be 0.8 mm, 1.2 mm, 1.4 mm, etc.), and the thickness of the basic thick sheet is 5 mm (proven in practice, the values ​​may also be 2 mm, 3 mm, 9 mm, etc.).

[0043] The elastic thin sheet is a long strip formed by splicing two or more elastic thin segments along the length direction; the basic thick sheet is a long strip formed by splicing more than one basic thick segment along the length direction; the lengths of the basic thick segments are equal, and the lengths of the elastic thin segments are also equal.

[0044] Each basic thick segment is covered with elastic thin segments along the length direction, and the length of the basic thick segment is twice the length of the elastic thin segment, that is, the same basic thick segment is covered with two elastic thin segments along the length direction; each elastic thin segment is provided with two positioning bosses, and the height of the positioning bosses is 2mm; each basic thick segment is provided with four positioning recessed holes, and the recessed depth of the positioning recessed holes is 2.1mm; the positioning bosses and the positioning recessed holes can be freely matched, that is, any positioning boss can be matched in any positioning recessed hole; a total of four positioning bosses on the two elastic thin segments are movably fitted in the four positioning recessed holes on the basic thick segments where they are located.

[0045] One end of each elastic thin segment and each basic thick segment in the thickness direction is a fixed end and the other end is a free end. The fixed end of each elastic thin segment is provided with three equidistant waist-shaped mounting holes, and the fixed end of each basic thick segment is provided with six equidistant waist-shaped mounting holes; the six waist-shaped mounting holes on the two elastic thin segments are aligned with the six waist-shaped mounting holes on the basic thick segment.

[0046] Each basic thick segment and the corresponding elastic thin segment are installed on the radial partition of the air preheater rotor by means of mounting bolts that simultaneously pass through the waist-shaped mounting holes of both (the elastic thin segment and the basic thick segment), and the free end of the elastic thin segment exceeds the free end of the basic thick segment.

[0047] In practice, with the above-mentioned multi-piece sealing structure of the air preheater, when the elastic thin sheet has problems such as wear and blow damage, the elastic thin sheet can be replaced separately in segments. Only the installation bolts in the waist-shaped installation holes corresponding to the segments need to be removed. Since the length of the elastic thin segment is only 1 / 2 of the length of the corresponding basic thick segment, removing the installation bolts of the waist-shaped installation holes corresponding to one elastic thin segment will not cause the installation position of the basic thick segment to change. The relative position between the elastic thin segment and the basic thick segment is fixed through the cooperation relationship of the positioning boss and the positioning concave hole, so as to ensure that the sealing sheet does not need to be reinstalled and positioned as a whole, saving the replacement and maintenance costs.

[0048] Example 2

[0049] On the basis of Example 1, the following further improvements are made: For the convenience of disassembly and assembly, the positioning boss is circular ring-shaped, the positioning concave hole is waist-shaped, and the length direction of the positioning concave hole is the same as the length direction of the basic thick sheet. The shapes and sizes of all positioning bosses are the same, and the shapes and sizes of all positioning concave holes are the same. The width of the positioning concave hole is 0.2 mm larger than the diameter of the positioning boss (verified by practice, it can also take values such as 0.3 mm, 0.5 mm, 0.7 mm, etc.), and the length of the positioning concave hole is 5 mm larger than the diameter of the positioning boss (verified by practice, it can also take values such as 3 mm, 7 mm, 9 mm, etc.) 2 - 10 mm.

[0050] Example 3

[0051] On the basis of Example 2, the following further improvements are made: For the convenience of processing and manufacturing, the above-mentioned positioning concave hole is a through hole, and the positioning boss is welded on the elastic thin sheet.

[0052] Example 4

[0053] On the basis of Example 2, the following further improvements are made: To improve the overall sealing performance, the above-mentioned positioning concave hole is a blind hole, and the positioning boss is welded on the elastic thin sheet.

[0054] Example 5

[0055] Different from Example 3 or 4: The length of the basic thick segment is three times the length of the elastic thin segment. That is, three elastic thin segments are covered along the length direction on the same basic thick segment; two waist-shaped installation holes are provided at the fixed ends of each elastic thin segment, and six equally spaced waist-shaped installation holes are provided at the fixed ends of each basic thick segment; the six waist-shaped installation holes on the three elastic thin segments are aligned with the six waist-shaped installation holes on the corresponding basic thick segment, and the rest refer to Example 3 or 4.

[0056] Example 6

[0057] Differing from Example 5: The same section of the thick base segment corresponds to three elastic thin segments of unequal lengths, and the lengths of the three elastic thin segments are 1 / 2, 1 / 3, and 1 / 6 of the length of the thick base segment where they are located. Compared with Example 5, the production in this example is relatively complex and requires processing elastic thin segments of different lengths.

[0058] A method for replacing elastic thin sheets of a multi-sheet sealing structure of an air preheater. Using the above-mentioned multi-sheet sealing structure of an air preheater that is easy to replace elastic thin sheets, when the elastic thin sheet is damaged, determine the damaged elastic thin segment, remove the installation bolts in the kidney-shaped installation holes corresponding to the damaged elastic thin segment, and replace the elastic thin segment.

[0059] If there are more than two damaged elastic thin segments on the same section of the thick base segment, replace them one by one (that is, after replacing one elastic thin segment, then remove and replace the next one). Since the length of the elastic thin segment is not greater than 2 / 3 of the length of the thick base segment where it is located, when removing the installation bolts in the kidney-shaped installation holes corresponding to one elastic thin segment, the remaining installation bolts on the thick base segment cooperate with the positioning convex and concave holes, and will not cause the installation position of the thick base segment to change, and there is no need for overall reinstallation and positioning.

[0060] The elastic thin segments not on the same section of the thick base segment can be replaced simultaneously or one by one.

[0061] For the above-mentioned multi-sheet sealing structure of an air preheater that is easy to replace elastic thin sheets in each example, the relative position between the elastic thin segment and the thick base segment is fixed through the matching of the positioning convex and concave holes. When there are problems such as wear and blow damage to the elastic thin sheet, the elastic thin sheet can be replaced separately in sections. Only the installation bolts in the corresponding kidney-shaped installation holes need to be removed. Since the length of the elastic thin segment is not greater than 2 / 3 of the length of the thick base segment where it is located, removing the installation bolts in the kidney-shaped installation holes corresponding to one elastic thin segment will not cause the installation position of the thick base segment to change. Therefore, when replacing the elastic thin segment, there is no need for repositioning, which saves the disassembly, installation, and maintenance costs, and the structure is simple and stable, and the disassembly and installation are simple and convenient.

[0062] The above embodiments do not limit the present invention in any form. All technical solutions obtained by using equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. An air preheater multi-piece sealing structure with easily replaceable elastic sheets, comprising at least one elastic sheet and at least one basic thick sheet stacked in the thickness direction, each elastic sheet having a thickness between 0.8 and 1.6 mm, and each basic thick sheet having a thickness between 2 and 10 mm; characterized in that: The elastic thin sheet is a long strip formed by splicing two or more elastic thin segments along the length direction; the basic thick sheet is a long strip formed by splicing one or more basic thick segments along the length direction; The same thick basic segment is covered with more than two thin elastic segments along the length direction, and the length of each thin elastic segment is no more than 2 / 3 of the length of the thick basic segment; each thin elastic segment is provided with more than two positioning bosses, and the height of the positioning bosses is at least 2mm; each thick basic segment is provided with more than four positioning concave holes, and the concave depth of the positioning concave holes is at least 2mm; the positioning bosses and the positioning concave holes can be matched freely; the positioning bosses on each thin elastic segment are all movably matched in the positioning concave holes on the thick basic segment; One end of each elastic thin segment and each basic thick segment in the width direction is a fixed end, and the other end is a free end. The fixed ends of each elastic thin segment and each basic thick segment are provided with waist-shaped mounting holes, and the waist-shaped mounting holes on each elastic thin segment are aligned with the waist-shaped mounting holes on the basic thick segment where they are located; Each basic thick segment and the corresponding elastic thin segment are mounted on the radial partition of the air preheater rotor by means of mounting bolts that simultaneously pass through waist-shaped mounting holes of the two segments, and the free end of the elastic thin segment exceeds the free end of the basic thick segment.

2. The multi-piece seal structure of the air preheater with easily replaceable elastic sheets according to claim 1, characterized in that: The positioning boss is in the shape of a circular ring, the positioning concave hole is in the shape of a waist, and the length direction of the positioning concave hole is consistent with the length direction of the basic thick sheet.

3. The multi-piece seal structure of the air preheater with easily replaceable elastic sheets according to claim 2, characterized in that: The width of the positioning concave hole is 0.2-1 mm larger than the diameter of the positioning boss, and the length of the positioning concave hole is 2-10 mm larger than the diameter of the positioning boss.

4. The multi-piece seal structure of the air preheater with easily replaceable elastic sheets according to any one of claims 1-3, characterized in that: The height of the positioning boss is not greater than the depth of the positioning recess.

5. The multi-piece seal structure of the air preheater with easily replaceable elastic sheets according to any one of claims 1-3, characterized in that: The positioning recessed hole is a through hole or a blind hole.

6. The multi-piece seal structure of the air preheater with easily replaceable elastic sheets according to any one of claims 1-3, characterized in that: Each basic thick segment is covered with elastic thin segments along the length direction.

7. The multi-piece seal structure of the air preheater with easily replaceable elastic sheets according to any one of claims 1-3, characterized in that: The lengths of the elastic thin segments on the same basic thick segment are equal, and the length of the basic thick segment is an integer multiple of the length of the corresponding elastic thin segment.

8. The multi-piece seal structure of the air preheater with an easily replaceable elastic sheet according to any one of claims 1-3, characterized in that: The lengths of the basic thick segments are equal, and the lengths of the elastic thin segments are also equal.

9. According to any one of claims 1 to 3, the multi-plate sealing structure of an air preheater with easily replaceable elastic sheets, the positioning boss is welded on the elastic sheet.

10. A method for replacing an elastic sheet of a multi-piece seal structure of an air preheater, characterized in that: The air preheater multi-plate sealing structure with easy replacement of elastic sheets as described in any one of claims 1 to 9 is adopted. When the elastic sheet is damaged, the damaged elastic sheet segment is determined, and the mounting bolts in the waist-shaped mounting holes corresponding to the damaged elastic sheet segment are removed to replace the elastic sheet segment; If more than two elastic thin segments are damaged on the same thick foundation segment, they should be replaced one by one. Since the length of the elastic thin segment is not greater than 2 / 3 of the length of the thick foundation segment, the mounting bolts of the waist-shaped mounting holes corresponding to one of the elastic thin segments should be removed. The remaining mounting bolts on the thick foundation segment will cooperate with the positioning boss positioning concave holes, which will not cause the installation position of the thick foundation segment to change, and there is no need to reinstall and reposition the entire segment. The elastic thin segments not on the same base thick segment can be replaced simultaneously or one by one.

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