A rotary air preheater

Abstract

The present invention provides a rotary air preheater, comprising a rotor and stators arranged at the upper and lower ends of the rotor, and sealing elements arranged radially and circumferentially between the rotor and the stator. The sealing elements are fixed to the end of the rotor and rotate synchronously with the rotor during the operation of the rotary air preheater, and the surface of the sealing element forms a dynamic contact seal with the end face of the stator. The rotary air preheater comprises a pressure ring arranged above the stator, and the sealing elements include a first seal and a second seal. The first seal is fixed to the pressure ring and is at least pressed between the pressure ring and the stator, and the second seal is fixed to the end of the rotor. During the operation of the rotary air preheater, on the one hand, there is no problem of radial partitions being worn, and on the other hand, it can ensure that the sector plate is always in a gapless contact seal with the sealing element. Moreover, as the use time increases, the flexibility and air leakage rate of the rotary air preheater will hardly change.

Description

Technical Field

[0001] The invention relates to heat exchange equipment, in particular to a rotary air preheater. Background Art

[0002] The air leakage problem of rotary air preheater has always been a hot topic in this field. The main reasons for the air leakage are the mushroom-shaped deformation and wear of the sealing parts during the operation of the rotary air preheater.

[0003] There are three main types of sealing structures for existing rotary air preheaters. The first is a rotary air preheater with a brush seal device, as disclosed in document CN101071048A. Brush seals are installed radially between each radial bin baffle and the sector plate of the rotor, axially between the outer edge of the rotor and the fixed shell, and circumferentially between the outer circumference of the upper and lower surfaces of the rotor and the fixed shell. The second is a contact labyrinth seal structure, which uses the principle of labyrinth seal to completely cover the gap between the moving parts and the stationary parts. The deformation amount can be changed according to the change of the sealing gap under different loads, and the seal can be spread out to prevent air leakage in all directions. The third is an elastic seal structure, which is used to eliminate the working gap between the rotor and the sealing plate by arranging a spring device on the sealing plate of the rotor.

[0004] However, rotary air preheaters using the aforementioned conventional sealing structure are unable to achieve a long-term reduction in air leakage to 5% or even lower. Although document CN101071048A claims to significantly reduce air leakage in rotary air preheaters, with leakage reduced to 1 / 5 to 1 / 10 of that of labyrinth seals, in actual operation, once the seal brushes bend (to accommodate rotor deformation), gaps within the brushes themselves develop, leading to increased air leakage and failing to achieve the claimed technical effect. Furthermore, the aforementioned conventional rotary air preheaters suffer from complex structures, requiring frequent maintenance during operation. Furthermore, they suffer from poor stability and flexibility over long periods of use. Generally, the longer they are used, the less flexible they become and the greater their air leakage. Summary of the Invention

[0005] The object of the present invention is to provide a rotary air preheater, which at least solves the technical problem of the existing rotary air preheater that "the longer the service time, the worse the flexibility and the greater the air leakage rate".

[0006] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions.

[0007] A rotary air preheater comprises a rotor and stators arranged at the upper and lower ends of the rotor, and sealing elements arranged radially and circumferentially between the rotor and the stator. The sealing element is characterized in that the sealing element is fixed to the end of the rotor and rotates synchronously with the rotor during operation of the rotary air preheater, and the surface of the sealing element forms a dynamic contact seal with the end face of the stator.

[0008] In the present invention, the rotary air preheater also includes a pressure ring arranged above the stator, and the sealing element includes seal 1 and seal 2. Seal 1 is fixed on the pressure ring and is at least pressed between the pressure ring and the stator, and seal 2 is fixed at the end of the rotor.

[0009] As a preferred solution of the present invention, the seal member 1 is annular, a portion of the seal member 1 is press-fitted between the pressing ring and the stator, and another portion is press-fitted between the pressing ring and the rotor.

[0010] In order to further improve the sealing, stability and flexibility of the rotary air preheater during long-term use, the sealing member 1 includes graphite packing A, graphite packing B and high-temperature lubricating grease, and the high-temperature lubricating grease is contained between graphite packing A and graphite packing B; or, the sealing member 1 includes graphite packing A and high-temperature lubricating grease.

[0011] As a preferred embodiment of the present invention, the graphite packing A and / or the high-temperature lubricating grease are press-fitted between the pressing ring and the rotor, and the graphite packing B is press-fitted between the pressing ring and the stator.

[0012] As a more preferred embodiment of the present invention, the sealing member 1 is a graphite packing C having a stepped axial cross section.

[0013] To further enhance the rotary air preheater's sealing, stability, and flexibility during long-term use, Seal 1 is secured to the rotor via adjustable fasteners. Seal 2 is secured to the rotor's dynamic outer ring and radial baffles, while the stator's static outer ring and sector plates rest against the surface of Seal 2. In the present invention, the adjustable fasteners allow for varying the amount of preload applied to Seal 1, thereby enhancing sealing.

[0014] In order to further solve the problem of frequent maintenance required during the operation of the rotary air preheater, the rotor includes a central tube and an outer tube, which are fixedly connected by a plurality of radial partitions arranged at intervals, and a heat exchange unit is arranged in the space enclosed by the central tube, the outer tube and the radial partitions; the stator includes a fan-shaped plate, a static outer ring and a static inner ring connected to the fan-shaped plate and adapted to the rotor.

[0015] To better address the technical issues of rotary air preheaters, which often suffer from decreased flexibility and increased air leakage over time, one or more annular baffles are installed between the central and outer cylinders. Graphite packing is secured to these baffles, forming a continuous sliding surface in the circumferential direction and resting against the sector plates. The graphite packing on these baffles forms a dynamic contact seal with the sector plates. This structure cleverly avoids interference between the sector plates and the graphite packing on the radial baffles. Furthermore, a counterweight is placed on the upper surface of the sector plates above the rotor, while a disc spring assembly supports the lower surface of the sector plates below the rotor.

[0016] As a more preferred embodiment of the present invention, the second seal includes a strip graphite packing D adapted to the radial partition of the rotor, and an annular graphite packing E adapted to the dynamic outer ring of the rotor, and the upper surface of the strip graphite packing D and the upper surface of the annular graphite packing E are located on the same horizontal plane.

[0017] The present invention has the following beneficial effects.

[0018] Due to the adoption of the above technical solution, during the operation of the rotary air preheater, on the one hand, there is no problem of radial partition being worn, and on the other hand, it can be ensured that the sector plate is always in gapless contact and sealing with the sealing element, and as the service time increases, the flexibility and air leakage rate of the rotary air preheater will hardly change; the rotary air preheater provided by the present invention has an air leakage rate of less than 3% during the initial and long-term operation; the rotary air preheater provided by the present invention can adapt to the thermal expansion and contraction of the rotor, has excellent stability and flexibility during operation, and does not have any problems of sticking. It also has the advantages of being easy to install, disassemble and maintain, and maintenance usually requires only the replacement of the sealing element. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of a rotary air preheater in an embodiment;

[0020] Figure 2 yes Figure 1 A magnified view of part II;

[0021] Figure 3 This is an enlarged view of part I of the rotary air preheater in Implementation Plan 1;

[0022] Figure 4 This is an enlarged view of part I of the rotary air preheater in Implementation Option 2;

[0023] Figure 5 This is an enlarged view of part I of the rotary air preheater in Implementation Plan 3;

[0024] Figure 6 This is an enlarged view of part I of the rotary air preheater in Implementation Option 4;

[0025] Figure 7 This is an enlarged view of part I of the rotary air preheater in Embodiment 5;

[0026] Figure 8 is a radial cross-sectional schematic diagram of the rotary air preheater in Example 6;

[0027] Figure 9 is a partial cross-sectional schematic diagram of the annular baffle of the rotary air preheater in Example 6;

[0028] Figure 10 This is a partial cross-sectional schematic diagram of the annular partition of the rotary air preheater in Example 7. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following embodiments are only intended to help understand the principles and core concepts of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that for those skilled in the art, improvements made to the present invention without departing from the principles of the present invention also fall within the scope of protection of the claims of the present invention.

[0030] Implementation Plan 1

[0031] First, the main structure of the rotary air preheater in the present invention is described. Figure 1 、 Figure 2 As shown, the rotary air preheater includes a drive mechanism 20, a rotor, and stators mounted at the upper and lower ends of the rotor, as well as sealing elements radially and circumferentially disposed between the rotor and the stator. The sealing elements are fixed to the rotor ends and rotate synchronously with the rotor during operation. The surfaces of the sealing elements form a dynamic contact seal with the end faces of the stator. The drive mechanism 20 is connected to the rotor and used to drive its rotation. The rotor comprises a central cylinder 26 and an outer cylinder 3. A dynamic outer ring 5 is mounted at the upper end of the outer cylinder 3. The central cylinder 26 and the outer cylinder 3 are fixedly connected via multiple spaced radial baffles 15. A heat exchange unit 22 is located within the space enclosed by the central cylinder 26, the outer cylinder 3, and the radial baffles 15. The stator comprises sector plates (upper sector plate 23 and lower sector plate 25), a stator outer ring 16 connected to the sector plates and compatible with the rotor, and a stator inner ring. Multiple disc spring assemblies 24 are evenly supported on the lower surface of the sector plates below the rotor.

[0032] The sealing element (structure) of the rotary air preheater of the present invention will be described in detail in conjunction with a specific implementation scheme.

[0033] Combine Figure 3As shown, the rotary air preheater also includes a pressure ring 11 arranged above the stator. The pressure ring 11 is connected to the dynamic outer ring 5 of the rotor through an adjustable fastener 12. The sealing element includes a seal 1 and a seal 2. The seal 1 is fixed on the pressure ring 11 and is at least pressed between the pressure ring 11 and the stator. The seal 1 is annular and is used to form an annular seal. Specifically, a part of the seal 1 is pressed between the pressure ring 11 and the stator, and the other part is pressed between the pressure ring 11 and the outer cylinder 3 of the rotor; the seal 2 is fixed to the end of the rotor. More specifically, seal 1 includes graphite packing A18, graphite packing B9 and high-temperature lubricating grease 10. The high-temperature lubricating grease 10 is contained between graphite packing A18 and graphite packing B9. Graphite packing A18 and high-temperature lubricating grease 10 are press-fitted between the pressure ring 11 and the dynamic outer ring 5 of the rotor, and the graphite packing B9 is press-fitted between the pressure ring 11 and the static outer ring 16 of the stator. Seal 2 includes a strip graphite packing D6 adapted to the radial partition 15 of the rotor, and an annular graphite packing E19 adapted to the dynamic outer ring 5 of the rotor, and the upper surface of the strip graphite packing D6 and the upper surface of the annular graphite packing E19 are located on the same horizontal plane. The annular graphite packing E19 is fixed to the dynamic outer ring 5 by a fastener 7. Figure 3 The lower surface of the middle annular graphite packing E19 is against the upper surface of the dynamic outer ring 5, and the upper surface is against the static outer ring 16. The strip graphite packing D6 is fixed to the end of the radial partition 15 by fasteners 27. Figure 3 The lower surface of the middle strip graphite packing D6 abuts against the upper end surface of the radial partition 15, and the upper surface abuts against the upper sector plate 23. The annular graphite packing E19 and the strip graphite packing D6 can adopt a split structure or an integrated structure.

[0034] During use, the preload on seal 1 can be adjusted by adjusting the adjustable fastener 12. During the operation of the rotary air preheater, on the one hand, there is no problem of wear of the radial partition 15. As the air cooler runs, only slight wear will occur on the contact surface between seal 1, seal 2 and the sector plate. On the other hand, it can ensure that the sector plate is always in gapless contact and sealing with the sealing element. During the initial and long-term operation of the rotary air preheater, its air leakage rate is less than 3%, and with the extension of the use time, the flexibility and air leakage rate of the rotary air preheater will hardly change.

[0035] Implementation Plan 2

[0036] A rotary air preheater, referring to embodiment 1 and combined with Figure 1 、 Figure 2 and Figure 4As shown, the main difference from Implementation Option 1 is that a spring 14 is provided on the adjustable fastener 12, the upper end of the spring 14 rests on its nut and the lower end rests on the pressure ring 11. Before use, the spring 14 can be pre-pressed to an appropriate amount. As the rotary air preheater operates, the wear of the seal 1 is automatically compensated with the help of the spring 14.

[0037] Implementation Plan 3

[0038] A rotary air preheater, combined with Figure 1 、 Figure 2 and Figure 5 As shown, the rotary air preheater also includes a pressure ring 11 arranged above the stator. The pressure ring 11 is connected to the dynamic outer ring 5 of the rotor through an adjustable fastener 12. The sealing element includes a seal 1 and a seal 2 (the seal 2 is indicated by the number 61). The seal 1 is fixed on the pressure ring 11 and is simultaneously pressed between the pressure ring 11 and the stator, and the pressure ring 11 and the rotor. The seal 2 is fixed to the end of the rotor. Specifically, one part of the seal 1 is pressed between the pressure ring 11 and the stator, and the other part is pressed between the pressure ring 11 and the rotor. Among them, the first seal adopts an annular graphite packing C17 with a stepped axial cross-section. The stepped surface of the annular graphite packing C17 is in contact with the surface of the upper sector plate 23 to form an annular seal, and a gap 13 is provided between the annular graphite packing C17 and the side wall of the second seal; the second seal includes a strip graphite packing adapted to the radial partition 15 of the rotor, and an annular graphite packing adapted to the dynamic outer ring 5 of the rotor. The annular graphite packing and the strip graphite packing are integrally formed, and the upper surface of the strip graphite packing and the upper surface of the annular graphite packing are located on the same horizontal plane. The second seal is fixed to the dynamic outer ring 5 and the radial partition 15 by fasteners 7 and fasteners 27. Figure 5 As shown, the lower surface of seal 2 abuts the upper surface of the movable outer ring 5 and the upper end surface of the radial partition 15, and the upper surface of seal 2 abuts the upper sector plate 23. During use, the preload on seal 1 is adjusted by adjusting the adjustable fastener 12. During operation of the rotary air preheater, the radial partition 15 is not subject to wear. As the air cooler operates, only slight wear occurs on the contact surfaces of seals 1 and 2 with the sector plates. This ensures that the sector plates always maintain a seamless contact seal with the sealing element. During initial and long-term operation, the air leakage rate of this rotary air preheater is less than 3%. Furthermore, the flexibility and air leakage rate of the rotary air preheater remain virtually unchanged over time.

[0039] Implementation Plan 4

[0040] A rotary air preheater, referring to embodiment 1 and combined with Figure 1 、 Figure 2 and Figure 6As shown, the main difference from embodiment 1 is that the high-temperature lubricating grease 10 contacts the upper end face of the moving outer ring 5, the side end face of the annular graphite packing E19, the side end face and the upper surface of the upper sector plate 23 at the same time to form a seal.

[0041] Implementation Plan 5

[0042] Refer to Implementation Plan 1 and combine Figure 1 、 Figure 2 and Figure 7 As shown, the main difference from Implementation Option 1 is that the high-temperature lubricating grease 10 contacts the upper end face of the moving outer ring 5, the side end face of the annular graphite packing E19 and the side end face of the upper fan-shaped plate 23 at the same time to form a seal, and the top surface of the high-temperature lubricating grease 10 is higher than the upper surface of the upper fan-shaped plate 23.

[0043] In the aforementioned embodiments, the high-temperature lubricating grease 10 can be replaced by flame-retardant and heat-resistant lubricating grease or sealant.

[0044] In the aforementioned embodiments, only the sealing structure of the upper edge of the outer cylinder 3 is illustrated as an example. The sealing structure of the lower edge of the outer cylinder 3, the upper edge of the center cylinder 26, and the sealing structure of the lower edge of the center cylinder 26 are similar to the aforementioned embodiments, but the defined directions should be adaptively adjusted.

[0045] During specific implementation, the skin is mounted on the stator, and the skin connection portion is arranged on the inner side of the pressing ring 11 or the outer side of the pressing ring 11 .

[0046] Implementation Plan 6

[0047] A rotary air preheater, referring to embodiment 1 and combined with Figure 8 、 Figure 9 As shown, the main difference from embodiment 1 is that one or more annular partitions 4 are arranged between the central tube 26 and the outer tube 3, and the graphite packing 2 is fixed on the annular partition 4 and abuts against the sector plate. The upper surface of the annular partition 4 is flush with the upper surface of the radial partition 15 and the upper surface of the movable outer ring 5 of the rotor, and the top surface of the graphite packing 2 abuts against the lower surface of the upper sector plate 23. Such a structure divides the radial sealing structure into multiple sections, and the graphite packing 2 fixed on the annular partition 4 forms a continuous sliding surface in the circumferential direction to avoid mutual interference between the upper sector plate 23 and the graphite packing D6 on the radial partition 15.

[0048] Implementation Plan 7

[0049] A rotary air preheater, referring to embodiment 1 and combined with Figure 8 、 Figure 10As shown, the main difference from embodiment 1 is that one or more annular partitions 4 are provided between the central tube 26 and the outer tube 3, and the graphite packing 2 is fixed on the annular partition 4 and abuts against the sector plate. The upper surface of the annular partition 4 is higher than the upper surface of the radial partition 15, and the top surface of the graphite packing 2 abuts against the lower surface of the upper sector plate 23. The graphite packing 2 fixed on the annular partition 4 forms a continuous sliding surface in the circumferential direction to avoid mutual interference between the upper sector plate 23 and the graphite packing D6 on the radial partition 15.

[0050] Implementation Plans 8-12

[0051] A rotary air preheater, referring to Examples 1-7 respectively, differs from the aforementioned corresponding embodiments in that a counterweight 8 is provided on the upper surface of the upper sector plate 23 above the rotor.

[0052] The aforementioned rotary air preheater, on the one hand, does not have the problem of radial partitions being worn, and on the other hand, can ensure that the fan plate is always in gapless contact and sealing with the sealing element. Moreover, as the service time increases, the flexibility and air leakage rate of the rotary air preheater will hardly change; during the initial and long-term operation of the aforementioned rotary air preheater, its air leakage rate is less than 3%; the aforementioned rotary air preheater can adapt to the thermal expansion and contraction of the rotor, and has excellent stability and flexibility during operation, and there is no problem of jamming at all. It also has the advantages of being easy to install, disassemble and maintain, and maintenance usually only requires replacing the sealing element.

Claims

1. A rotary air preheater comprising a rotor, stators disposed at the upper and lower ends of the rotor, and sealing elements radially and circumferentially disposed between the rotor and the stator, characterized in that: The sealing element is fixed to the end of the rotor and rotates synchronously with the rotor during the operation of the rotary air preheater, and the surface of the sealing element and the end face of the stator form a dynamic contact seal; the rotary air preheater also includes a pressure ring (11) arranged above the stator, and the sealing element includes a sealing member 1 and a sealing member 2, the sealing member 1 is fixed to the pressure ring (11) and is at least pressed between the pressure ring (11) and the stator, and the sealing member 2 is fixed to the end of the rotor; the sealing member 1 is annular, and a part of the sealing member 1 is pressed on the pressure ring (11) The rotor comprises a central tube (26) and an outer tube (3), the central tube (26) and the outer tube (3) being fixedly connected by a plurality of radial partitions (15) arranged at intervals, and a heat exchange unit (22) is provided in a space enclosed by the central tube (26), the outer tube (3) and the radial partitions (15); the stator comprises a sector plate, a stationary outer ring (16) and a stationary inner ring connected to the sector plate and adapted to the rotor.

2. The rotary air preheater according to claim 1, characterized in that: The sealing member 1 includes a graphite packing A (18), a graphite packing B (9) and a high-temperature lubricating grease (10), wherein the high-temperature lubricating grease (10) is accommodated between the graphite packing A (18) and the graphite packing B (9); or, the sealing member 1 includes a graphite packing A (18) and a high-temperature lubricating grease (10).

3. The rotary air preheater according to claim 2, characterized in that: The graphite packing A (18) and / or the high-temperature lubricating grease (10) are pressed between the pressing ring (11) and the rotor, and the graphite packing B (9) is pressed between the pressing ring (11) and the stator.

4. The rotary air preheater according to any one of claims 1 to 3, characterized in that: The first seal is fixed to the rotor via an adjustable fastener, the second seal is fixed to the moving outer ring (5) and the radial partition (15) of the rotor, and the static outer ring (16) and the sector plate of the stator are in contact with the surface of the second seal.

5. The rotary air preheater according to claim 4, characterized in that: One or more annular partitions (4) are provided between the central cylinder (26) and the outer cylinder (3), and the graphite packings provided on the annular partitions (4) form a dynamic contact seal with the sector plates.

6. The rotary air preheater according to claim 5, characterized in that: The second seal comprises a strip graphite packing D (6) adapted to the radial partition (15) of the rotor, and an annular graphite packing E (19) adapted to the moving outer ring (5) of the rotor, and the upper surface of the strip graphite packing D (6) and the upper surface of the annular graphite packing E (19) are located on the same horizontal plane.

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