A shaft seal ring with an air seal structure and a generator

Abstract

This invention relates to a shaft seal ring with a gas-sealing structure, comprising an outer ring plate, an inner ring plate, and a sealing plate. The inner ring plate is fixedly connected to the inner ring of the outer ring plate, and one end face of the inner ring plate extends out of the inner ring of the outer ring plate. A first groove is formed along the circumference of the inner ring plate, and a plurality of spaced throttling holes are formed in the first groove along the circumference. One end face of the sealing plate is fixedly installed on the outer ring plate, and the other end face of the sealing plate is fixedly installed on the outer ring of the inner ring plate, so that the sealing plate, the outer ring plate, and the inner ring plate together form a first cavity. The first groove communicates with the first cavity through the throttling holes. The first cavity communicates with an air inlet on the outer ring plate. The beneficial effect is that the combined design of the first groove and throttling holes ensures that the sealing gas is evenly distributed in the circumferential direction of the inner ring plate, forming a stable and effective gas-sealing environment with high sealing efficiency.

Description

Technical Field

[0001] This invention relates to the field of mechanical seal technology, specifically to a shaft seal ring with an air seal structure and a generator. Background Technology

[0002] Air-cooled turbine generators use internally circulated dry air as the cooling medium, achieving direct cooling of the stator and rotor through a closed airflow path and a water-cooled heat exchanger. Therefore, the sealing system at the shaft penetration end cover is crucial for the generator's long-term reliable operation. The core function of this seal is to effectively prevent contaminants such as dust, oil mist, and humid air from entering the generator through the shaft clearance. The accumulation of these contaminants on the surfaces of the high-voltage coils and insulators significantly reduces insulation strength, causing partial discharge or even short circuits, and is one of the main factors leading to generator failure.

[0003] Currently, air-cooled generators commonly employ labyrinth seals, felt seals, or simple lip seals. These traditional solutions have the following limitations: 1. Insufficient protection: The above-mentioned sealing methods are passive seals, which have limited effectiveness in blocking micron-sized particles (such as PM2.5 and industrial dust) and oil mist. When the generator expands and contracts due to load changes, it is prone to a "breathing effect," drawing pollutants into the machine. The protection level is usually insufficient to meet the long-term operating requirements under harsh conditions.

[0004] 2. Wear and maintenance issues: Contact seals will wear down after long-term operation, which not only leads to an increase in sealing gap and a decline in effectiveness, but the particles generated by the wear also constitute a new source of pollution. Regular shutdowns for inspection and replacement are required, resulting in high maintenance costs.

[0005] 3. Limited functionality and lack of proactiveness: The existing sealing structure is merely a physical barrier, unable to provide proactive and effective defense against the intrusion of external contaminants. Maintenance personnel struggle to monitor changes in the sealing status in real time, cannot provide early warnings before contaminant intrusion intensifies, and lack predictive maintenance methods.

[0006] Therefore, there is an urgent need in this field for a new type of shaft seal solution that can provide a higher level of protection, has active defense capabilities, and is easy to monitor for conditions, in order to improve the operational reliability of air-cooled generators in complex industrial environments. Summary of the Invention

[0007] This invention addresses the technical problems existing in the prior art by providing a shaft seal ring with an air seal structure and a generator.

[0008] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: In a first aspect, the present invention protects a shaft seal ring with an air seal structure, comprising an outer ring plate, an inner ring plate, and a sealing plate; The inner ring plate is fixedly connected to the inner ring of the outer ring plate, and one end face of the inner ring plate extends out of the inner ring of the outer ring plate. A first groove is provided along the circumference of the inner ring plate, and a plurality of throttling holes are provided in the first groove along the circumference. One end face of the sealing plate is fixedly installed on the outer ring plate, and the other end face of the sealing plate is fixedly installed on the outer ring of the inner ring plate, so as to form a first cavity with the outer ring plate and the inner ring plate. The first groove communicates with the first cavity through the throttling hole. The first cavity is connected to the air inlet on the outer ring plate, and gas is supplied to the first groove to form an airtight environment on the inner ring of the inner ring plate. As a further technical solution, an air-guiding block is provided on one end face of the sealing plate away from the center of the inner ring plate. The air-guiding block has a hollow structure and is connected to the air inlet.

[0009] As a further technical solution, the diameter of the plurality of first throttling holes opened in the first groove gradually increases in the direction away from the air-guiding block; The first throttling orifice and the first groove share the same center line.

[0010] As a further technical solution, a sealing groove is provided along the circumferential direction of the inner ring plate, and a sealing element is embedded in the sealing groove.

[0011] As a further technical solution, the end of the seal that is away from the sealing groove extends out of the sealing groove.

[0012] As a further technical solution, the sealing groove is provided at both ends of the first groove axis, and the bottom surface of the sealing groove is located below the bottom surface of the first groove.

[0013] As a further technical solution, both the inner ring plate and the outer ring plate are split in half, and are connected by a connecting plate on the outer ring plate to form a circular ring structure.

[0014] A second aspect of the present invention protects a generator, comprising a shaft seal ring as described in the first aspect, the shaft seal ring being mounted on the outer end cover of the generator, and a gap being present between the inner ring of the inner ring plate and the outer wall of the upper rotating shaft of the generator.

[0015] As a further technical solution, a gas supply device is also included. The gas supply device includes a four-way connector, a first air inlet pipe, a solenoid valve, a second air inlet pipe, and a pressure monitoring unit; The A port of the four-way connector is connected to one end of the first intake pipe through the solenoid valve, and the other end of the first intake pipe is connected to the inner end cover of the generator. The B port of the four-way connector is connected to one end of the second air intake pipe, and the other end of the second air intake pipe is connected to the shaft seal ring to form a passive air supply system, so that the air in the generator enters the first groove in sequence through the first air intake pipe, the four-way connector, the second air intake pipe, the first cavity, and the first throttle hole to form an air seal on the surface of the rotating shaft. The C port of the four-way connector is equipped with a pressure monitoring unit, and the D port of the four-way connector is connected to an external air supply device to form an active air supply system. When the pressure monitoring unit detects that the pressure is lower than the set value, it inputs gas into the first groove through the four-way connector, the second air inlet pipe, the first cavity, and the first throttling orifice via the external device to form an air seal on the surface opposite to the rotating shaft.

[0016] As a further technical solution, the gas supply device is provided in two parts, and is symmetrically arranged along the shaft seal ring.

[0017] The beneficial effects of this invention are: 1. The combined design of the first groove, throttling hole, etc., ensures that the sealing gas is evenly distributed in the circumferential direction of the inner ring plate to form a stable and effective gas sealing environment with high sealing efficiency. 2. The design of several throttling holes in the first groove with diameters gradually increasing away from the air-drawing block allows the gas to enter through the air-drawing block, be distributed in the first cavity and move to the first groove along the corresponding throttling holes, thereby improving the uniformity of the gas entering the first groove and making the gas distribution more uniform along the circumference of the inner ring plate, thus improving the sealing effect. 3. The design of the sealing groove and the first groove allows gas to gradually diffuse through the first groove, so that when the shaft seal ring is connected with other structures, an airtight environment is formed at this location; 4. The shaft seal ring is installed on the generator with a gap between it and the shaft to form a non-contact seal, avoiding friction between the shaft seal ring and the shaft, and preventing the generation of wear particles, which significantly extends the equipment maintenance cycle and service life. 5. The specific structural design of the gas supply device forms an active gas supply system and a passive gas supply system, which can be switched according to the pressure changes under operating conditions. This ensures the continuity and reliability of the seal under various operating conditions (especially critical stages such as start-up, shutdown, and low load), greatly improving the operational safety of the entire generator system. In addition, the use of two gas supply devices, which are symmetrically distributed, improves the gas supply efficiency and the uniformity of the gas supply, thereby forming a stable seal. 6. The shaft seal ring of the present invention can be designed as a semi-split structure, consisting of two semi-circular structures, left and right, which are fixed on the outer end cover of the generator for easy on-site installation and maintenance. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a shaft seal ring structure containing an air seal structure according to the present invention; Figure 2 This is a schematic diagram of a shaft seal ring with an air seal structure according to the present invention, split into two halves. Figure 3 This is a partial structural diagram of a shaft seal ring with an air seal structure according to the present invention after being cut open; Figure 4 This is a partial structural diagram of a generator after the shaft seal ring of the present invention has been installed; Figure 5 This is a partial structural diagram of a generator after it has been cut open and fitted with the shaft seal ring of the present invention, wherein the arrows indicate the direction of gas flow.

[0019] The attached diagram lists the components represented by each number as follows: Outer ring plate 1, air inlet 11, connecting plate 12, stiffening plate 13, mounting hole 14; Inner ring plate 2, first groove 21, throttling orifice 22, sealing groove 23, inclined surface 231, sealing element 24. Sealing plate 3, air duct 31; First cavity 4; Generator 5, outer end cover 51, inner end cover 52; Shaft 6; 7. Gas supply device; 71. Four-way connector; 72. First air inlet pipe; 73. Solenoid valve; 74. Second air inlet pipe; 75. Pressure monitoring unit; Fan 8. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0022] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0023] Example 1 See Figures 1-3 This embodiment provides a shaft seal ring with a gas seal structure, including an outer ring plate 1, an inner ring plate 2, and a sealing plate 3. The inner ring plate 2 is fixedly connected to the inner ring of the outer ring plate 1, and one end face of the inner ring plate 2 extends out of the inner ring of the outer ring plate 1. A first groove 21 is formed along the circumference of the inner ring of the inner ring plate 2, and a plurality of spaced throttling holes 22 are formed in the first groove 21 along the circumference. One end face of the sealing plate 3 is fixedly installed on the outer ring plate 1, and the other end face of the sealing plate 3 is fixedly installed on the outer ring of the inner ring plate 2, so as to form a first cavity 4 with the outer ring plate 1 and the inner ring plate 2. The first groove 21 communicates with the first cavity 4 through the throttling holes 22. The first cavity 4 communicates with the air inlet 11 opened on the outer ring plate 1, and by providing gas to the first groove 21, a gas seal environment is formed on the inner ring of the inner ring plate 2.

[0024] It should be noted that the shaft seal ring in this embodiment is annular in shape. For example, the outer diameter is adapted to the generator model. For instance, when it is installed on a 35MW steam turbine generator, a reliable seal is required at the end cover of the generator shaft 6 to prevent the entry of foreign objects. In this case, the outer diameter of the shaft seal ring can be 800mm. For example, the shaft seal ring in this embodiment has a split structure, that is, both the inner ring plate 2 and the outer ring plate 1 are split in half, and are connected by the connecting plate 12 on the outer ring plate 1 to form a circular ring structure. Specifically, it is divided into two semicircles, left and right, and fixed on the outer end cover 51 of the generator 5 for easy on-site installation and maintenance.

[0025] It should be noted that each of the two semicircular outer ring plates 1 is provided with a connecting plate 12, which can be connected by bolts to form a complete ring. Correspondingly, the inner ring plate 2 is also divided into two semicircular inner ring plates 2 and fixed on the corresponding semicircular outer ring plate 1. There are two sealing plates 3, which are symmetrically arranged on the two semicircular outer ring plates 1 to correspond to the throttling holes 22 on the corresponding inner ring plates 2. That is, the arc length of one of the sealing plates 3 is greater than or equal to the arc length required to open the throttling hole 22 on the semicircular inner ring plate 2, so that after the gas enters through the sealing plate 3, it is evenly distributed into the first groove 21 through a number of throttling holes 22 to form a stable gas sealing environment.

[0026] For example, each semicircular outer ring plate 1 is provided with two connecting plates 12, which are located on the same straight line to facilitate disassembly. For example, it also includes stiffening plates 13, and several stiffening plates 13 are provided, evenly distributed along the circumference of the outer ring plate 1; one end face of the stiffening plate 13 is vertically fixed to the outer ring plate 1, and the other end face of the stiffening plate 13 is fixed to the outer ring of the inner ring plate 2, which strengthens the strength of the shaft seal ring in this embodiment, while also enhancing the stability of the outer ring plate 1 and the inner ring plate 2. For example, four stiffening plates 13 are provided and evenly distributed on the shaft seal ring, improving the balance of force and strength.

[0027] For example, mounting holes 14 are provided along the edge of the outer ring plate 1 in the circumferential direction, and the plate can be installed on the equipment to be installed by bolts, for example, on the outer end cover 51 of the generator.

[0028] In this embodiment, the design of the first groove 21 and the throttling hole 22 ensures that the pressure distribution of the sealing gas is uniform in the circumferential direction, forming a stable and effective air curtain barrier with a high sealing effect.

[0029] See Figure 1 , Figure 3 In the specific implementation process, an air-guiding block 31 is provided on one end face of the sealing plate 3 away from the center of the inner ring plate 2. The air-guiding block 31 is a hollow structure and is connected to the air inlet 11. That is, the gas enters the cavity of the air-guiding block 31 through the air inlet 11. Since the cavity of the air-guiding block 31 is connected to the first cavity 4, the gas enters the first cavity 4 and then enters the throttling hole 22, and then enters the first groove 21, so that the inner ring of the inner ring plate 2 forms an air seal environment between the inner ring plate 2 and the corresponding mounting part (e.g., the rotating shaft 6) through the first groove 21. Moreover, this structural design allows the inner ring of the inner ring plate 2 to not directly contact the mounting part, thereby improving the service life of the mounting part and reducing friction.

[0030] Furthermore, the diameter of the plurality of first throttling orifices 22 formed within the first groove 21 gradually increases in the direction away from the air-guiding block 31, and the first throttling orifices 22 and the first groove 21 share a common centerline. This structural design ensures that the diameter of the throttling orifice 22 closest to the air-guiding block 31 is the smallest, while the diameter of the throttling orifice 22 further away from the air-guiding block 31 becomes larger, thereby making the air pressure entering the first groove 21 more uniform and thus improving the stability of the air seal.

[0031] See Figures 1-3 In the specific implementation process, a sealing groove 23 is formed along the circumference of the inner ring plate 2, and a sealing element 24 is embedded in the sealing groove 23. Effective sealing is achieved through the sealing element 24. For example, the sealing element 24 is a sealing ring, such as a copper ring.

[0032] Furthermore, the end of the seal 24 that is away from the sealing groove 23 extends out of the sealing groove 23, and the end face of the seal 24 that extends out of the sealing groove 23 is a slope 231, and the slope direction is the direction of the center of the inner ring plate 2, which can reduce the possible contact area with the rotating shaft 6 under abnormal conditions.

[0033] Furthermore, both ends of the first groove 21 are provided with the sealing groove 23, and the bottom surface of the sealing groove 23 is located below the bottom surface of the first groove 21 to provide sufficient air pressure so that a stable air seal environment is formed between the shaft seal ring and the rotating shaft 6 after installation, preventing contaminants from entering and preventing new contaminants from being generated due to friction. This eliminates the need for regular shutdown for inspection and replacement, reducing maintenance costs.

[0034] The cross-sectional structure of the first groove 21 can be rectangular.

[0035] The shaft seal ring protected in this embodiment has an air seal structure composed of the first groove 21, the throttling hole 22, and the first cavity 4, which can achieve a non-contact seal for the rotating shaft 6, and will not rub against the rotating shaft 6, thus improving its service life.

[0036] For example, in this embodiment, the shaft seal ring is formed by welding Q235B carbon steel plate. The specific manufacturing process is as follows: First, a CNC plasma cutting machine is used to cut the plate into an outer ring plate 1, a stiffening plate 13, an inner ring plate 2, and a connecting plate 12. At the same time, a CNC milling machine is used to machine the air intake block 31. Then, gas shielded welding (MAG) is used to weld these parts into place. After welding, stress-relieving annealing is performed, and finally, precision machining is carried out on a large CNC vertical lathe, focusing on ensuring the inner hole size of the inner ring plate 2 and the size and dimensional tolerances of the sealing groove 23. That is, in this embodiment, welded parts can be used to replace traditional castings, fundamentally eliminating leakage problems caused by casting defects. The product consistency is good, the manufacturing flexibility is high, the production cycle is short, and it is easier to ensure quality.

[0037] Example 2 See Figure 4 , Figure 5 This embodiment provides a generator, including a shaft seal ring as described in Embodiment 1. The shaft seal ring is installed on the outer end cover 51 of the generator 5, and there is a gap between the inner ring of the inner ring plate 2 and the outer wall of the upper rotating shaft 6 of the generator 5.

[0038] For example, taking a 35MW steam turbine generator as an example, the outer diameter of the shaft seal ring is 800mm, and the single-sided gap between the inner diameter of the seal 24 and the rotating shaft 6 of the generator 5 is 0.3-0.5mm, so as to ensure that the inner ring of the seal 24 and the outer wall of the rotating shaft 6 are in a non-contact state under any operating conditions, avoiding friction between the seal 24 and the rotating shaft 6, not generating wear particles, and significantly extending the equipment maintenance cycle and service life; for example, the width of the first groove 21 is 35mm and the depth is 10mm.

[0039] See Figure 4 , Figure 5In its specific implementation, the system also includes an air supply device 7, which comprises a four-way connector 71, a first air inlet pipe 72, a solenoid valve 73, a second air inlet pipe 74, and a pressure monitoring unit 75. Port A of the four-way connector 71 is connected to one end of the first air inlet pipe 72 via the solenoid valve 73, and the other end of the first air inlet pipe 72 is connected to the inner end cover 52 of the generator 5. Port B of the four-way connector 71 is connected to one end of the second air inlet pipe 74, and the other end of the second air inlet pipe 74 is connected to the shaft seal ring to form a passive air supply system. This allows air from inside the generator 5 to sequentially enter the first groove 21 through the first air inlet pipe 72, the four-way connector 71, the second air inlet pipe 74, the first cavity 4, and the first throttling orifice 22 when the generator is operating normally, forming an air seal on the surface of the rotating shaft 6. In other words, this passive air supply system utilizes the positive pressure zone (approximately 1.5-2.5 bar) formed at the inner end cover 52 of the generator 5 when the high-pressure fan 8 on the generator shaft 6 rotates. (kPa) is used as the air source, and it is connected through the first air inlet pipe 72, the second air inlet pipe 74, and the four-way connector 71 (that is, the air source enters the shaft seal ring from the first air inlet pipe 72 through the four-way connector 71 and the second air inlet pipe 74 to form an air seal environment with the rotating shaft 6).

[0040] The pressure monitoring unit 75 is installed at port C of the four-way connector 71, and port D of the four-way connector 71 is connected to an external air supply device (such as an air compressor as a backup air source, with an exhaust pressure of 0.8 MPa and an exhaust volume of 100 L / min, and the outlet of the air compressor is stabilized at 5 kPa by a pressure reducing valve before being connected to port D of the four-way connector 71) to form an active air supply system. When the pressure monitoring unit 75 detects that the pressure is lower than the set value, it inputs gas into the first groove 21 through the four-way connector 71, the second air inlet pipe 74, the first cavity 4, and the first throttling orifice 22 via an external device to form an air seal on the surface opposite to the rotating shaft 6. This structural design can realize both active and passive air supply modes, and can automatically and seamlessly switch the air source according to the working conditions, which greatly improves the reliability and intelligence level of the generator shaft seal, and is particularly suitable for the power industry with extremely high requirements for operational reliability.

[0041] It should be noted that the pressure monitoring unit 75 is a digital display pressure monitoring unit 75 (e.g., range 0-10kPa, output 4-20mA signal) to monitor the gas path pressure in real time.

[0042] It should be noted that both the first air intake pipe 72 and the second air intake pipe 74 are oil-resistant and pressure-resistant rubber hoses to improve their service life.

[0043] It should be noted that there are two air supply devices 7, which are symmetrically arranged along the shaft seal ring. That is, one air supply device 7 corresponds to half of the shaft seal ring, and the two air supply devices 7 are located on the same straight line to improve the uniformity of air supply to the shaft seal ring.

[0044] This embodiment is implemented as follows: 1. During normal operation, the generator speed reaches 3000 r / min, and the high-pressure fan 8 generates sufficient positive pressure. The air pressure monitored by the pressure monitoring unit 75 is stable at around 2.0 kPa, which is higher than the set action threshold (e.g., 1.0 kPa). At this time, the solenoid valve 73 is de-energized and closed, and the air compressor does not work. Clean air from inside the generator 5 moves from port A to port B through the first intake pipe 72 via the four-way connector 71, and then enters the cavity of the induced draft block 31 through the second intake pipe 74. It then enters the first groove 21 through the throttling orifice 22, and finally forms a uniform and stable air curtain on the surface of the rotating shaft 6, achieving effective sealing.

[0045] 2. Low-pressure intervention: When generator 5 starts, stops, or operates under low load, the pressure generated by high-pressure fan 8 decreases. When pressure monitoring unit 75 detects a pressure below 1.0 kPa for 3 seconds (to avoid false triggering), generator 5's control system (DCS or PLC) immediately issues a command: first, start the air compressor, and simultaneously energize and open solenoid valve 73. After solenoid valve 73 opens, it cuts off the passive air path from port A to port B of four-way connector 71, and instead opens the active air source, i.e., the path from port D to port B of four-way connector 71. Thus, the clean compressed air pipe provided by the air compressor continues to provide air sealing power to the shaft seal ring, ensuring the continuity of the seal.

[0046] 3. When the generator speed returns to normal and the passive air supply pressure rises and stabilizes above 1.2 kPa, the control system will first close the solenoid valve 73 after a 30-second delay, and then stop the air compressor. The system will automatically switch back to the more economical passive air supply mode. The shaft seal ring manufacturing process in this embodiment is simple and low-cost, free of casting defects, and can achieve long-term operation without contact or wear. The constructed generator has both active and passive air sources, which can automatically and seamlessly switch according to operating conditions, improving the reliability of the shaft seal ring on the generator and the safety of the entire generator system.

[0047] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0048] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0049] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A generator, characterized in that, It includes a shaft seal ring with an air seal structure and an air supply device (7); the shaft seal ring includes an outer ring plate (1), an inner ring plate (2), and a sealing plate (3); The inner ring plate (2) is fixedly connected to the inner ring of the outer ring plate (1), and one end face of the inner ring plate (2) extends out of the inner ring of the outer ring plate (1). A first groove (21) is provided along the circumference of the inner ring plate (2), and a plurality of throttling holes (22) are provided in the first groove (21) along the circumference. One end face of the sealing plate (3) is fixedly installed on the outer ring plate (1), and the other end face of the sealing plate (3) is fixedly installed on the outer ring of the inner ring plate (2) so as to form a first cavity (4) together with the outer ring plate (1) and the inner ring plate (2). The first groove (21) is connected to the first cavity (4) through the throttling hole (22). The first cavity (4) is connected to the air inlet (11) on the outer ring plate (1), and by providing gas to the first groove (21), a gas-sealed environment is formed on the inner ring of the inner ring plate (2); The shaft seal ring is installed on the outer end cover (51) of the generator, and there is a gap between the inner ring of the inner ring plate (2) and the outer wall of the upper rotating shaft (6) of the generator; The gas supply device (7) includes a four-way connector (71), a first air inlet pipe (72), a solenoid valve (73), a second air inlet pipe (74), and a pressure monitoring unit (75); The A port of the four-way connector (71) is connected to one end of the first intake pipe (72) through the solenoid valve (73), and the other end of the first intake pipe (72) is connected to the inner end cover (52) of the generator. The B port of the four-way connector (71) is connected to one end of the second air intake pipe (74), and the other end of the second air intake pipe (74) is connected to the shaft seal ring to form a passive air supply system, so that the air in the generator enters the first groove (21) in sequence through the first air intake pipe (72), the four-way connector (71), the second air intake pipe (74), the first cavity (4), and the throttle hole (22) to form an air seal on the surface of the rotating shaft (6); The pressure monitoring unit (75) is installed at the C port of the four-way connector (71), and the D port of the four-way connector (71) is connected to an external gas supply device to form an active gas supply system. When the pressure monitoring unit (75) detects that the pressure is lower than the set value, it inputs gas into the first groove (21) through the four-way connector (71), the second air inlet pipe (74), the first cavity (4), and the throttle hole (22) through the external device to form an air seal on the surface opposite to the rotating shaft (6).

2. A generator according to claim 1, characterized in that, An air-guiding block (31) is provided on one end face of the sealing plate (3) away from the center of the inner ring plate (2). The air-guiding block (31) is a hollow structure and is connected to the air inlet (11).

3. A generator according to claim 2, characterized in that, The diameter of the plurality of throttling holes (22) opened in the first groove (21) gradually increases in the direction away from the air duct (31); The throttling orifice (22) shares a common centerline with the first groove (21).

4. A generator according to claim 1, characterized in that, A sealing groove (23) is provided along the circumferential direction of the inner ring plate (2), and a sealing element (24) is embedded in the sealing groove (23).

5. A generator according to claim 4, characterized in that, The end of the seal (24) opposite to the sealing groove (23) extends out of the sealing groove (23).

6. A generator according to claim 5, characterized in that, The sealing groove (23) is provided at both ends of the axis of the first groove (21), and the bottom surface of the sealing groove (23) is located below the bottom surface of the first groove (21).

7. A generator according to any one of claims 1-6, characterized in that, The inner ring plate (2) and the outer ring plate (1) are both split in half and connected by a connecting plate (12) on the outer ring plate (1) to form a circular ring structure.

8. A generator according to claim 1, characterized in that, The gas supply device (7) is provided in two parts and is symmetrically arranged along the shaft seal ring.

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