Radial non-contact sealing system of air preheater based on elastic compensation module

Abstract

This invention relates to the field of radial sealing technology for rotary air preheaters, aiming to solve the problem of increased air leakage rate caused by hot deformation. The system provided in this application includes: an elastic compensation module (2), a reversing amplification mechanism (3), a hinged support (7), a sealing limiting roller (4), and a sealing plate (5). The elastic compensation module (2) generates a driving force when heated and expands. After being amplified by the reversing amplification mechanism (3), it drives the sealing plate (5) to rotate and lift around the hinged support (7), compensating for the mushroom-shaped deformation gap of the rotor in real time. The sealing limiting roller (4) contacts the fan-shaped plate (1) before the sealing plate (5), limiting excessive lifting and maintaining a 2-20mm non-contact sealing gap. This invention requires no electrical control, has a simple structure, fast response speed, long service life, and low maintenance cost. It can significantly reduce the air leakage rate of the air preheater and improve the boiler operating efficiency.

Description

Technical Field

[0001] This application relates to the field of rotary air preheaters (hereinafter referred to as air preheaters), and particularly to a radial non-contact sealing system for air preheaters based on an elastic compensation module. Background Technology

[0002] Rotary air preheaters are key energy-saving devices in large-scale thermal power plant boiler systems. They periodically absorb heat from flue gas through rotor heat storage elements and release it to the combustion air entering the furnace, achieving waste heat recovery and improved combustion efficiency. Reliable operating data shows that a 1% increase in air preheater leakage rate leads to a 0.06-0.08 g / kWh increase in the unit's coal consumption for power generation, while significantly increasing the power consumption of forced and induced draft fans, resulting in energy waste and accelerated equipment wear, directly impacting the power plant's economy and safety. Therefore, controlling the leakage rate remains one of the core technical challenges in improving the overall operating efficiency of the boiler.

[0003] Air preheater leakage mainly consists of carry-over leakage and direct leakage. Carry-over leakage originates from the air carried by the cavities between the heat storage elements inside the rotor during rotation, typically accounting for 80%-85% of the rotor volume, with a leakage rate of approximately 1.5%-2%. Aside from appropriately reducing the rotational speed, there are currently no economically effective control methods. Direct leakage, driven by the pressure difference between the air and flue gas sides, leaks through the dynamic and static gaps between the sealing plates, sector plates, and the outer casing. This leakage accounts for the majority of the total leakage and is a key focus of technical upgrades. As units develop towards larger capacities and higher parameters, the problem of increased radial sealing gaps caused by hot mushroom-shaped deformation of the rotor becomes increasingly prominent, significantly increasing the difficulty of controlling the hot leakage rate.

[0004] To reduce direct air leakage, existing technologies mainly include traditional contact seals, adjustable seals (SBS), and spring-loaded flexible seals. Contact seals achieve sealing through the mechanical contact between the sealing plate and the sector plate; however, long-term friction leads to rapid wear of the sealing plate, high operating resistance, and risks of jamming and dust leakage. Adjustable seals require complex electro-hydraulic drive systems, gap detection sensors, and control units. While they can achieve automatic gap tracking, they suffer from system response lag, poor sensor reliability in high-temperature and high-dust environments, high maintenance costs, and low equipment uptime. Spring-loaded flexible seals utilize elastic force to compensate for thermal deformation, but the spring elements are prone to failure due to long-term high-temperature corrosion and fatigue, resulting in high replacement costs and poor economic efficiency. None of the above solutions achieves an ideal balance between sealing effect, operational reliability, maintenance cost, and service life. There is an urgent need for a new sealing system that is simple in structure, responds quickly, adaptable to all operating conditions, and is economical. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a radial non-contact sealing system for an air preheater based on an elastic compensation module, comprising: an elastic compensation module (2), a reversing amplification mechanism (3), a hinged support (7), a sealing limit roller (4), and a sealing sheet (5). The hinge support (7) is fixedly mounted on the radial partition (8) of the air preheater rotor; the sealing plate (5) is mounted on the radial partition (8), the inner end of the sealing plate (5) is hinged to the hinge support (7), and the outer end of the sealing plate (5) is hinged to one end of the commutation amplification mechanism (3); the elastic compensation module (2) is mounted on the radial partition (8), and its two ends are respectively hinged to the radial partition (8) and the commutation amplification mechanism (3); the sealing limiting roller (4) is fixedly mounted on the commutation amplification mechanism (3), and is configured to contact the sector plate (1) before the sealing plate (5) contacts the sector plate (1); the sealing limiting roller (4) is located on the front side of the sealing plate (5) along the rotor rotation direction, and its highest point is higher than the upper surface of the sealing plate (5); The elastic compensation module (2) generates a driving force when heated and expands. This force is amplified by the reversing amplification mechanism (3) and drives the sealing sheet (5) to rotate and lift around the hinge support (7). When the sealing sheet is lifted to the preset position, the sealing limiting roller (4) contacts the sector plate (1) and restricts the further lifting of the sealing sheet (5), so that the sealing sheet (5) and the sector plate (1) remain in a non-contact sealing state.

[0006] Optionally, the elastic compensation module (2) includes: an elastic body (21), a high-pressure inert gas (22) filled inside the elastic body (21), a metal protective shell (23) covering the outside of the elastic body (21), and hinge holes (24) provided at both ends of the module.

[0007] Optionally, the metal protective shell (23) is composed of multiple hard metal plates overlapping and interlacing.

[0008] Optionally, the reversing amplification mechanism (3) includes: a mechanism body, a first hinge rod (31) disposed at one end of the mechanism body, and a second hinge rod (32) disposed at the other end of the mechanism body; the mechanism body is provided with an obliquely arranged sliding groove (33), and a fixed cylindrical pin (34) is provided in the sliding groove (33) to slide with it, and the fixed cylindrical pin (34) is fixedly connected to the radial partition (8).

[0009] Optionally, the hinged support (7) is located at the first bolt hole position on the inner end of the radial partition (8).

[0010] Optionally, the sealing limiting roller (4) includes: a base (41) fixed on the reversing amplification mechanism (3), a rotating shaft (42) mounted on the base (41), and a metal roller (43) rotatably mounted on the rotating shaft (42).

[0011] Optionally, the sealing sheet (5) is composed of multiple bent metal sheets and a substrate, and its length is adapted to the radius of the air preheater rotor.

[0012] Optionally, the pressure value of the high-pressure inert gas (22) is set according to the hot deformation of the air preheater.

[0013] Optionally, the sliding groove (33) is arranged at an angle of 30° to 75° with the horizontal direction.

[0014] Optionally, it also includes a gap-filling plate (6), which is fixedly disposed at the outermost radial end of the radial partition (8) and closely fits the outer side of the sealing sheet (5).

[0015] The technical solutions provided in this application embodiment may include the following beneficial effects: (1) The system structure provided in this application is simple and does not require electrical control equipment. It can achieve radial non-contact sealing effect of air preheater, reduce air preheater leakage rate, and the leakage control effect is close to that of traditional automatic leakage control system.

[0016] (2) The present invention has no electrical control equipment and does not require manual control operation. Due to the protective effect of the sealing limit roller, the sealing plate will not increase the running resistance of the air preheater due to friction with the sector plate, thereby improving the overall system safety and reliability and reducing maintenance costs.

[0017] (3) The system provided in this application uses the thermal expansion of gas to control the system action. The system action is related to the ambient temperature. Compensation and rotor mushroom deformation are carried out synchronously, and the action is responded to in real time.

[0018] (4) It is economical, has a simple structure, is easy to process, has low production costs, and a short system investment payback period.

[0019] (5) The system provided in this application is a compact integrated design, which occupies little space, is highly adaptable, and is easy to install and disassemble.

[0020] (6) Since the system has no electrical control components, only the hinged parts may be damaged. The calculated lifespan can exceed 3 major overhaul cycles. The structure is not easily damaged and has strong stability.

[0021] (7) The system provided in this application has a wide range of applications. By designing different elastic compensation modules and commutation amplification mechanisms, it can be adapted to the needs of different air preheater models. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0023] Figure 1a This is an exemplary embodiment of the present application, showing the overall layout (without sector plates); Figure 1b This is an exemplary embodiment of the present application, showing the overall layout (with sector plates); Figure 2 This is a partial enlarged view of the overall arrangement diagram provided in an exemplary embodiment of this application; Figure 3 This is a schematic diagram of the mushroom-shaped deformation of the air preheater rotor provided in an exemplary embodiment of this application; Figure 4 This is a schematic diagram of the cold state provided in an exemplary embodiment of this application; Figure 5 This is a schematic diagram of the thermal state provided in an exemplary embodiment of this application; Figure 6 This is a partially enlarged schematic diagram of the cold state provided in an exemplary embodiment of this application; Figure 7 This is a schematic diagram illustrating the operational relationship between the system and the sector plate provided in an exemplary embodiment of this application; Figure 8a This is a schematic diagram of the elastic compensation module structure provided in an exemplary embodiment of this application; Figure 8b This is a cross-sectional view of the elastic compensation module structure provided in an exemplary embodiment of this application; Figure 9a This is a schematic diagram of the reversing amplification mechanism and the sealing limiting roller provided in an exemplary embodiment of this application; Figure 9b This is a schematic diagram of a reversing amplification mechanism and a sealing limiting roller provided in an exemplary embodiment of this application. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0025] This application provides a radial non-contact sealing system for an air preheater based on an elastic compensation module. The system is installed on the radial partition 8 of the air preheater rotor to dynamically compensate for the increase in radial sealing gap caused by the hot mushroom-shaped deformation of the rotor.

[0026] refer to Figure 1a , Figure 1b and Figure 2 The sealing system includes an elastic compensation module 2, a commutation amplification mechanism 3, a hinge support 7, a sealing limiting roller 4, a sealing sheet 5, and a gap-filling plate 6. These components are arranged sequentially along the length of the radial partition 8, forming a mechanical sealing system that operates in conjunction with each other. The hinge support 7 is fixed to the first bolt hole at the inner end of the radial partition 8. The inner end of the sealing sheet 5 is hinged to the hinge support 7 via a pin, and its outer end is connected to the second hinge rod 32 of the commutation amplification mechanism 3. The elastic compensation module 2 is arranged on the radial partition 8 below the sealing sheet 5. One end of it is hinged to the radial partition 8 via a hinge hole 24, and the other end is hinged to the first hinge rod 31 of the commutation amplification mechanism 3. The sealing limiting roller 4 is fixedly installed on the body of the commutation amplification mechanism 3 and is located in front of the sealing sheet 5 along the rotor rotation direction. The gap-filling plate 6 is fixedly disposed at the outermost radial end of the radial partition 8 and is tightly fitted to the outer side of the sealing sheet 5.

[0027] like Figure 8a and Figure 8b As shown, the elastic compensation module 2 is the core driving component, consisting of an elastic body 21, a high-pressure inert gas 22, a metal protective shell 23, and hinge holes 24. The elastic body 21 is made of a high-temperature resistant elastic alloy material to form a bowl-shaped or corrugated tubular sealed cavity, filled with a high-pressure inert gas 22 such as nitrogen or argon at a pressure of 0.5-3.0 MPa. The elastic body 21 is externally covered by a metal protective shell 23 composed of multiple overlapping and interlaced hard alloy steel plates. The overlapping structure design of the protective shell 23 ensures that the elastic body 21 is not directly eroded by high-temperature flue gas or worn by dust during expansion and contraction. Mounting seats for the hinge holes 24 are welded or threaded to both ends of the module for hinged connections with the radial partition 8 and the reversing amplification mechanism 3.

[0028] refer to Figure 9a and Figure 9b The reversing and amplification mechanism 3 is an L-shaped or triangular rigid linkage structure. One end of the mechanism has a first hinge rod 31 that is hinged to the elastic compensation module 2, and the other end has a second hinge rod 32 that is hinged to the sealing plate 5. A sliding groove 33 is obliquely arranged in the middle of the mechanism body. The sliding groove 33 is precisely slidably engaged with a fixed cylindrical pin 34 welded and fixed to the radial partition 8. The arrangement angle α of the sliding groove 33 forms an angle of 30° to 75° with the horizontal direction. This angle determines the amplification ratio and reversing characteristics of the mechanism. When the elastic compensation module 2 expands due to heat, generating a lateral thrust that acts on the first hinge rod 31, the mechanism moves along the sliding groove 33, converting the lateral thrust into a vertically upward lifting force, which is output to the sealing plate 5 through the second hinge rod 32, thus realizing the reversing and amplification of the driving force.

[0029] The sealing and limiting roller 4 consists of a base 41, a rotating shaft 42, and a roller 43. The base 41 is fixed to the body of the reversing and amplifying mechanism 3 by bolts or welding. The rotating shaft 42 is vertically mounted on the base 41, and the roller 43 is rotatably mounted on the rotating shaft 42 via bearings. The installation height must ensure that the highest point of the roller 43 is 2-20 mm higher than the upper surface of the sealing plate 5, and it is positioned at the leading edge of the sealing plate 5 contacting the sector plate 1. This height difference determines the preset non-contact sealing gap value.

[0030] The sealing sheet 5 is composed of multiple bent metal sheets riveted or welded to the integral base plate. The length of the sealing sheet 5 is customized according to the radius of the air preheater rotor, covering the sealing area from the hinged support 7 to the outer end of the radial partition 8. The gap-filling plate 6 is an arc-shaped or flat wear-resistant steel plate, installed close to the outermost end of the radial partition 8, and is used to seal the radial gap formed between the sealing sheet 5 and the radial partition 8 after the sealing sheet 5 is raised.

[0031] The sealing system provided in this application will be further described below in conjunction with the specific working process.

[0032] Please see Figure 4 , Figure 6 In cold operating condition: Before the unit starts, the air preheater is at room temperature, and the rotor radial partition 8 and the sector plate 1 maintain the designed cold-state gap. At this time, the internal gas pressure of the elastic compensation module 2 is low, the sealing sheet 5 is in the initial low position, and the sealing limit roller 4 does not contact the sector plate 1.

[0033] Please see Figure 5 During normal hot-state compensation operation: When the unit is running at full load, the flue gas temperature rises, and the inert gas 22 inside the elastic compensation module 2 expands due to heat, pushing the elastic body 21 to elongate, generating a lateral driving force that acts on the commutation amplification mechanism 3. The commutation amplification mechanism 3 moves along the sliding groove 33, converting the lateral thrust into a vertically upward lifting force, driving the sealing plate 5 to rotate and lift around the hinged support 7, compensating for the mushroom-shaped deformation of the rotor. Figure 3 The increased radial air leakage gap ensures that a preset 2-20mm non-contact sealing gap is maintained between the sealing sheet 5 and the sector plate 1, significantly reducing the air leakage rate.

[0034] Please see Figure 7 During hot overcompensation: When hot temperature fluctuations or excessive pressure in the elastic compensation module 2 cause the sealing plate 5 to rise excessively, the sealing limit roller 4 contacts the sector plate 1 before the sealing plate 5. The sector plate 1 pushes the sealing limit roller 4, forcing the reversing amplification mechanism 3 to move downward as a whole, compressing the elastic compensation module 2, causing its internal pressure to rise adaptively until a new equilibrium state is reached, thereby ensuring that the sealing plate 5 never contacts the sector plate 1, avoiding mechanical collision and wear.

[0035] This article uses specific examples to illustrate the inventive concept in detail. The description of the above embodiments is only for the purpose of helping to understand the core idea of ​​the present invention. It should be noted that any obvious modifications, equivalent substitutions or other improvements made by those skilled in the art without departing from the inventive concept should be included within the protection scope of the present invention.

[0036] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the foregoing claims.

[0037] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

[0038] It should be understood that "multiple" as used in this article refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0039] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0040] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A radial non-contact sealing system for an air preheater based on an elastic compensation module, characterized in that, include: Elastic compensation module (2), reversing amplification mechanism (3), hinge support (7), sealing limit roller (4) and sealing plate (5); The hinge support (7) is fixedly mounted on the radial partition (8) of the air preheater rotor; the sealing plate (5) is mounted on the radial partition (8), the inner end of the sealing plate (5) is hinged to the hinge support (7), and the outer end of the sealing plate (5) is hinged to one end of the commutation amplification mechanism (3); the elastic compensation module (2) is mounted on the radial partition (8), and its two ends are respectively hinged to the radial partition (8) and the commutation amplification mechanism (3); the sealing limiting roller (4) is fixedly mounted on the commutation amplification mechanism (3), and is configured to contact the sector plate (1) before the sealing plate (5) contacts the sector plate (1); The elastic compensation module (2) generates a driving force when heated and expands. This force is amplified by the reversing amplification mechanism (3) and drives the sealing sheet (5) to rotate and lift around the hinge support (7). When the sealing sheet is lifted to the preset position, the sealing limiting roller (4) contacts the sector plate (1) and restricts the further lifting of the sealing sheet (5), so that the sealing sheet (5) and the sector plate (1) remain in a non-contact sealing state.

2. The sealing system according to claim 1, characterized in that, The elastic compensation module (2) includes: an elastic body (21), a high-pressure inert gas (22) filled inside the elastic body (21), a metal protective shell (23) covering the outside of the elastic body (21), and hinge holes (24) provided at both ends of the module.

3. The sealing system according to claim 2, characterized in that, The metal protective shell (23) is composed of multiple hard metal plates overlapping and interlacing.

4. The sealing system according to claim 1, characterized in that, The reversing amplification mechanism (3) includes: a mechanism body, a first hinge rod (31) disposed at one end of the mechanism body, and a second hinge rod (32) disposed at the other end of the mechanism body; the mechanism body is provided with an obliquely arranged sliding groove (33), and a fixed cylindrical pin (34) is provided in the sliding groove (33) to slide with it, and the fixed cylindrical pin (34) is fixedly connected to the radial partition (8).

5. The sealing system according to claim 1, characterized in that, The hinged support (7) is located at the first bolt hole position on the inner end of the radial partition (8).

6. The sealing system according to claim 1, characterized in that, The sealing limiting roller (4) includes: a base (41) fixed on the reversing amplification mechanism (3), a rotating shaft (42) mounted on the base (41), and a metal roller (43) rotatably mounted on the rotating shaft (42).

7. The sealing system according to claim 1, characterized in that, The sealing sheet (5) is composed of multiple bent metal sheets and a base plate, and its length is adapted to the radius of the air preheater rotor.

8. The sealing system according to claim 2, characterized in that, The pressure value of the high-pressure inert gas (22) is set according to the hot deformation of the air preheater.

9. The sealing system according to claim 4, characterized in that, The sliding groove (33) is arranged at an angle of 30° to 75° with the horizontal direction.

10. The sealing system according to claim 1, characterized in that, It also includes a gap-filling plate (6), which is fixedly disposed at the outermost radial end of the radial partition (8) and closely fits the outer side of the sealing sheet (5).

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