Shaft sealing system, generator set and sealing method

Abstract

The present application provides a shaft sealing system, a generator set and a sealing method. The shaft sealing system includes: an oil baffle body which is annularly arranged around the shaft to be sealed and is used to define an oil groove; a first annular sealing cavity is formed inside the oil baffle body; an air suction port is formed on the oil baffle body, and the air suction port is communicated with the first annular sealing cavity; a vacuum pump which is arranged outside the oil baffle body, and the inlet of the vacuum pump is communicated with the air suction port; and a sealing plate which is annularly arranged around the shaft; a radial gap is formed between the sealing plate and the shaft to be sealed; a second annular sealing cavity is formed inside the sealing plate, and the second annular sealing cavity is communicated with the radial gap; the sealing plate and the oil baffle body are at least axially fixed, and the first annular sealing cavity is communicated with the second annular sealing cavity. The present application aims to solve the technical problem in the prior art that due to the high-speed rotation of the shaft, there is mutual friction between the shaft and the sealing structure, and the sealing structure is worn, resulting in sealing failure.

Description

Technical Field

[0001] This application relates to the technical field of sealing devices for generator sets, and particularly to a shaft sealing system, a generator set, and a sealing method. Background Art

[0002] The oil mist in a water turbine unit comes from the bearing. When the unit is operating, the shaft rotates and stirs the oil in the oil sump, thereby generating bubbles. The operation of the bearing and the rotating components generate heat, accelerating the formation of bubbles in the oil. When the bubbles burst, oil mist is produced. Since the generation of oil mist causes the pressure inside the oil sump to be greater than the pressure outside the oil sump, the oil mist has the potential energy to escape from the oil sump, resulting in oil mist leakage. To avoid oil mist leakage, two structures, namely contact sealing and brush sealing, are adopted in the prior art. Both of these structures have a sealing structure that contacts the shaft. The sealing structure generates friction during the operation of the shaft, which leads to wear of the sealing structure and is prone to sealing failure. Summary of the Invention

[0003] This application provides a shaft sealing system and a sealing method, aiming to solve the technical problem in the prior art that due to the high-speed rotation of the shaft, there is mutual friction between the shaft and the sealing structure, resulting in wear of the sealing structure and sealing failure.

[0004] An embodiment of this application proposes a shaft sealing system for sealing a shaft, including:

[0005] An oil baffle body, which is annularly arranged around the shaft to be sealed and is used to define an oil sump; a first annular sealing cavity is provided inside the oil baffle body; an air suction port is opened on the oil baffle body, and the air suction port communicates with the first annular sealing cavity;

[0006] A vacuum pump, which is arranged outside the oil baffle body, and the inlet of the vacuum pump is communicated with the air suction port; and

[0007] A sealing plate, which is annularly arranged around the shaft to be sealed; there is a radial gap between the sealing plate and the shaft to be sealed; a second annular sealing cavity is provided inside the sealing plate, and the second annular sealing cavity communicates with the radial gap; the sealing plate and the oil baffle body are at least axially fixed, and the first annular sealing cavity communicates with the second annular sealing cavity.

[0008] Optionally, the sealing plate further has a throttling hole, and the second annular sealing cavity communicates with the first annular sealing cavity through the throttling hole.

[0009] Optionally, there are multiple throttling holes, and the multiple throttling holes are arranged at intervals along the circumferential direction of the shaft to be sealed.

[0010] Optionally, the sealing plate includes a first sealing tooth and a second sealing tooth respectively located on two axial sides of the second annular sealing cavity, and the first sealing tooth and the second sealing tooth are arranged at an axial interval along the sealed shaft; wherein, there is a first radial gap between the first sealing tooth and the sealed shaft, and there is a second radial gap between the second sealing tooth and the sealed shaft.

[0011] Optionally, a limiting protrusion is formed on the inner wall of the first annular sealing cavity, and the limiting protrusion contacts the sealing plate when the radial width of the radial gap reaches the maximum value, thereby restricting the sealing plate from continuing to move radially away from the sealed shaft along the sealed shaft.

[0012] Optionally, the oil baffle body is further provided with an air supplement port; the air supplement port and the air suction port are arranged at an interval and communicate with the oil sump; the shaft sealing system includes a first connecting pipe and a second connecting pipe, and two opposite ends of the first connecting pipe are respectively connected to the inlet of the vacuum pump and the air suction port; two opposite ends of the second connecting pipe are respectively connected to the outlet of the vacuum pump and the air supplement port;

[0013] wherein, a first regulating valve is arranged on the second connecting pipe.

[0014] Optionally, the shaft sealing system further includes a third connecting pipe and an oil mist treatment device; the third connecting pipe is connected in parallel with the second connecting pipe, and the third connecting pipe communicates with the oil mist treatment device; a second regulating valve is arranged on the third connecting pipe.

[0015] Optionally, the shaft sealing system further includes a control component, and the control component is configured to start the vacuum pump and / or adjust the opening degrees of the first regulating valve and the second regulating valve.

[0016] The present application also proposes a generator set, including the shaft sealing system as described above.

[0017] The present application also proposes a sealing method for sealing a shaft and applied to the shaft sealing system as described above; the sealing method includes: starting the vacuum pump to establish a vacuum environment in the first annular sealing cavity inside the oil baffle body, so that the air pressure inside the oil sump and the air pressure outside the oil sump are both lower than the air pressure inside the first annular sealing cavity, thereby enabling the gas outside the oil sump to enter the radial gap to form a wind wall to block the leakage of the oil sump from the radial gap.

[0018] In the technical solution of the embodiment of the present application, there is a radial gap between the sealing plate and the shaft. As a result, when the shaft rotates at a high speed, there will be no friction and wear between the sealing plate and the shaft, that is, in the technical solution of the present application, there will be no technical problem of sealing failure due to wear between the sealing plate and the shaft. Further, the sealing plate and the oil baffle body are at least axially fixed, and there is a second annular sealing cavity. The radial gap communicates with the first annular sealing cavity of the oil baffle body through the second annular sealing cavity. The oil baffle body has an air suction port communicating with the first annular sealing cavity and an air supply port communicating with the oil sump. The inlet of the vacuum pump is communicated with the air suction port, and the outlet of the vacuum pump is communicated with the air supply port. During operation, the vacuum pump is started, and a vacuum degree is generated in the first annular sealing cavity. Although the first pressure in the oil sump is greater than the second pressure outside the oil sump, both the first pressure and the second pressure are higher than the pressure in the first annular sealing cavity (the first annular sealing cavity is in a vacuum state). Therefore, the gas outside the oil sump will flow towards the oil sump and be sucked into the first annular sealing cavity together with the oil mist, thereby avoiding oil mist leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0020] Figure 1 is a schematic diagram of the sealing principle of the prior art sealing structure;

[0021] Figure 2 is a schematic diagram of the structure of the shaft sealing system in the embodiment of the present application;

[0022] Figure 3 is another schematic diagram of the structure of the shaft sealing system in the embodiment of the present application;

[0023] Figure 4 is a schematic diagram of the structure of the sealing plate in the embodiment of the present application;

[0024] Figure 5 is a schematic diagram of the vacuum pump circulation principle of the shaft sealing system in the embodiment of the present application.

[0025]

[0026] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0028] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless otherwise specifically defined.

[0029] In this application, the word "exemplary" is used to mean "serving as an example, illustration, or explanation". Any embodiment described as "exemplary" in this application is not necessarily to be construed as more preferred or more advantageous than other embodiments. In order for any person skilled in the art to implement and use the present invention, the following description is given. In the following description, details are set forth for the purpose of explanation. It should be understood that those of ordinary skill in the art can recognize that the present invention can be implemented without the use of these specific details. In other instances, well-known structures and processes are not described in detail to avoid unnecessary details from obscuring the description of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed in this application.

[0030] Refer to Figure 1 as shown, Figure 1 illustrates the shaft-seal structure-bearing system of a water turbine unit. The bearing system is arranged in the oil sump S3 defined by the seal structure 200'. Bubbles are generated when the shaft 500' rotates at a high speed; under the action of the heat generated by the friction between the bearing system and the shaft 500', the formation of bubbles is accelerated and the bubbles burst to generate oil mist in the oil sump S3. Since the pressure in the oil sump S3 is greater than the pressure outside the oil sump S3, the oil mist has the potential energy to escape from the oil sump S3. For this reason, the prior art uses contact seals and brush seals for sealing.

[0031] The structure of the contact seal includes an oil baffle body 100', on which sealing teeth are provided, and the sealing teeth are abutted against the shaft 500' through springs. The sealing teeth are always in contact with the shaft 500', so the sealing teeth are extremely easy to wear; and because the shaft 500' vibrates relative to the oil baffle body 100', the springs are in a vibrating state and are prone to vibration fatigue. For the above two reasons, the contact seal structure 200' has the deficiency of seal failure due to wear.

[0032] The structure of the brush seal is a structure formed by improving the structure of the contact seal. It replaces the structure of the spring and the sealing teeth with a brush. Compared with the contact seal structure, it has the advantages of simple structure, easy installation and no vibration damage. However, due to the mutual friction between the brush and the shaft 500', wear and hair shedding occur. Wear will cause seal failure; and hair shedding is also prone to cause hair debris to enter the oil sump S3, resulting in oil pollution. Further, the hair debris enters the oil film with the oil, which is very likely to damage the bearing of the shaft 500'.

[0033] In summary, in the prior art, there are technical problems that the seal structure is worn due to the mutual friction between the seal structure and the shaft, and then the seal fails. In order to effectively address the deficiencies existing in the prior art, the embodiments of the present application propose a non-contact shaft seal system and method, aiming to provide a shaft seal system in which the seal structure is non-contact with the shaft, so that the shaft maintains an appropriate gap with the seal structure during operation, and oil mist will not overflow from the gap.

[0034] Refer to Figure 2 and Figure 5 As shown, the embodiments of the present application first propose a shaft seal system. This shaft seal system is particularly applicable to the shaft seal of small units. The shaft seal system includes: an oil baffle body 100, the oil baffle body 100 is disposed around the shaft 500 to be sealed for defining an oil sump. In the following embodiments, the shaft 500 to be sealed is specifically referred to as the shaft 500. The oil baffle body 100 has a first annular seal cavity 120 inside; an air suction port 110 is provided on the oil baffle body 100, and the air suction port 110 communicates with the first annular seal cavity 120;

[0035] A vacuum pump 300, the vacuum pump 300 is disposed outside the oil baffle body 100, and the inlet of the vacuum pump 300 is communicated with the air suction port 110; and

[0036] A sealing plate 200, the sealing plate 200 being arranged annularly around the shaft 500; there is a radial gap S between the sealing plate 200 and the shaft 500; the sealing plate 200 has a second annular sealing cavity 210 therein, and the second annular sealing cavity 210 communicates with the radial gap S; the sealing plate 200 is at least axially fixed to the oil baffle body 100, and the first annular sealing cavity 120 communicates with the second annular sealing cavity 210.

[0037] In the technical solution of the embodiment of the present application, there is a radial gap S between the sealing plate 200 and the shaft 500. As a result, when the shaft 500 rotates at a high speed, there will be no friction and wear between the sealing plate 200 and the shaft 500. That is to say, in the technical solution of the present application, there will be no technical problem of sealing failure due to wear between the sealing plate 200 and the shaft 500. Further, the sealing plate 200 is at least axially fixed to the oil baffle body 100, and has a second annular sealing cavity 210. The radial gap S communicates with the first annular sealing cavity 120 of the oil baffle body 100 through the second annular sealing cavity 210. The oil baffle body 100 has an air suction port 110 communicating with the first annular sealing cavity 120. The inlet of the vacuum pump 300 is communicated with the air suction port 110. During operation, the vacuum pump 300 is started to generate a vacuum degree in the first annular sealing cavity 120. Although the first pressure in the oil sump is greater than the second pressure outside the oil sump, both the first pressure and the second pressure are greater than the pressure in the first annular sealing cavity 120. Therefore, the gas outside the oil sump will flow at a high speed towards the inside of the oil sump in the radial gap S to block the outward leakage of oil mist, and together with the oil mist, it can be sucked into the first annular sealing cavity 120 through the second annular sealing cavity 210, thereby avoiding the leakage of oil mist.

[0038] It should be noted that in the technical solution of the embodiment of the present application, the radial gap S needs to be maintained within an appropriate range to avoid the problem of sealing failure caused by too large a radial gap S. Implementers generally determine the value of the radial gap S in combination with the operating scenario of the unit, the sealing effect, and the vacuum degree that the vacuum pump 300 can generate, etc.

[0039] In the technical solution of the present application, the oil mist is mainly sealed by the wind speed in the outer sealing gap. The designed sealing wind speed is generally greater than or equal to 10 m / s, which is determined by the limiting speed of the sealed shaft surface. For example, when the limiting speed of the sealed shaft surface is 40 m / s, the sealing wind speed is taken to be greater than or equal to 20 m / s. Considering the shaft vibration and swing, the range of the radial gap S is 0.1 mm to 0.5 mm. For the sealed shaft with a small shaft diameter, the value of the radial gap S can be relatively small, and it is appropriate to take 0.15 - 0.25 mm; for the sealed shaft with a large diameter, the value of the radial gap S can be relatively large, and it is appropriate to take 0.25 mm - 0.45 mm. The air volume of the fan is determined according to the selected sealing gap and sealing wind speed.

[0040] In the technical solution of a specific embodiment, the pressure of the first annular seal cavity 120 can be measured by an instrument to be -3900 Pa (vacuum degree is 30 mbar), the pressure of the second annular seal cavity 210 is -3000 Pa (vacuum degree is 39 mbar), and the pressure difference between the two is 900 Pa; the pressure outside the oil sump is about -1000 Pa, and the pressure inside the oil sump is about 0 Pa. It can be seen from this that: the pressure of the second annular seal cavity 210 is much lower than the pressure outside the oil sump, and the air flow direction is from outside the oil sump to inside the oil sump. The measured air treatment gas volume entering the radial clearance S from outside the oil sump is about 150 m 3 / h. Combining with the designed clearance, the average flow velocity of the air inhaled from outside the oil sump is about 20 - 25 m / s. And when measuring the oil mist outside the oil sump, the oil mist concentration outside the oil sump cannot be measured (or the oil mist concentration is too low for the instrument to measure). Therefore, the above non-contact shaft seal system can effectively achieve the sealing effect.

[0041] During the operation of the shaft 500, there are irregular vibrations. Therefore, during the operation, the size of the radial clearance S is dynamically changing and is non-uniform in the circumferential direction; and the volume of the second annular seal cavity 210 is limited, and the pressure in the second annular seal cavity 210 is also non-uniform in the circumferential direction. For this reason, in order to effectively solve this technical problem and make the pressure as uniform as possible everywhere; referring to Figure 2 and Figure 4 shown, as an alternative implementation of the above embodiment, the sealing plate 200 further has throttle holes 220. There are multiple throttle holes 220, and the multiple throttle holes 220 are arranged at intervals along the circumferential direction of the shaft 500. The second annular seal cavity 210 communicates with the first annular seal cavity 120 through the throttle holes 220. By providing throttle holes 220 on the sealing plate 200; the throttle holes 220 adjust the air flow rate through the pressure difference between the second annular seal cavity 210 and the first annular seal cavity 120. Furthermore, although the pressure of the second annular seal cavity 210 is non-uniform everywhere, under the action of the throttle holes 220, the gas flow rate is made as uniform as possible, overcoming the technical problem of non-uniform gas flow rate caused by the irregular vibration of the shaft 500.

[0042] As an alternative implementation of the above embodiment, as Figure 2As shown, the sealing plate 200 includes a first sealing tooth 230 and a second sealing tooth 240 respectively located on the two axial sides of the second annular sealing cavity 210. The first sealing tooth 230 and the second sealing tooth 240 are arranged at an axial interval along the axis 500. Among them, the second sealing tooth 240 is farther from the oil groove than the first sealing tooth 230. There is a first radial gap S1 between the first sealing tooth 230 and the axis 500, and a second radial gap S2 between the second sealing tooth 240 and the axis 500. The air outside the oil groove is sucked in through the second radial gap S2 to form a wind wall that can block the leakage of oil mist from the first radial gap S1, and a part of the oil mist is sucked in through the first radial gap S1. In the embodiment, the first sealing tooth 230 and the second sealing tooth 240 are circumferentially integral structures formed around the axis 500.

[0043] As an alternative embodiment of the above embodiment, a limiting protrusion 140 is formed on the inner wall of the first annular sealing cavity. The limiting protrusion 140 contacts the sealing plate 200 when the radial width of the radial gap S reaches the maximum value, thereby restricting the sealing plate 200 from continuing to move radially away from the axis 500 along the axis 500. In the embodiment, due to the radial vibration of the axis 500 during operation, the axis 500 will also cause the sealing plate 200 to move radially during the movement, thus causing the radial gap S to become larger; when the radial gap S becomes larger, it is necessary for the vacuum pump 300 to generate a sufficient vacuum degree to form an effective seal; for this reason, in the technical solution of the embodiment of the present application, a limiting protrusion 140 is provided on the inner wall of the first annular sealing cavity. When the sealing plate 200 moves to contact the limiting protrusion 140 under the action of the radial vibration of the axis 500, the sealing plate 200 no longer continues to move radially away from the axis 500 along the axis 500, and at this time, the radial width between the sealing plate 200 and the axis 500 reaches the maximum value, avoiding the sealing failure caused by the excessive radial gap S.

[0044] In the embodiment, the setting position of the limiting protrusion 140 determines the maximum value of the radial gap S. The implementer specifically sets the setting position of the limiting protrusion 140 in combination with factors such as the sealing requirements and the vacuum degree that the vacuum pump 300 can generate, and no excessive limitation is made here.

[0045] After the vacuum pump 300 is started, the air extraction volume of the vacuum pump 300 includes the air intake volume outside the oil groove and the air intake volume inside the oil groove; at this time, the pressure inside the oil groove will gradually decrease, which will affect the oil level inside the oil groove; for this reason, in the embodiment of the present application, in order to balance the pressure inside the oil groove, such as Figure 3As shown, the oil baffle body 100 is further provided with an air supplement port 130, and the air supplement port 130 is communicated with the outlet of the vacuum pump 300; the air supplement port 130 and the suction port 110 are arranged at intervals and communicated with the oil sump. The gas at the outlet of the vacuum pump 300 will be sent back into the oil sump to keep the pressure in the oil sump within an appropriate pressure range.

[0046] As an alternative embodiment of the above embodiment, as Figure 5 shown, the shaft sealing system includes a first connecting pipe 310 and a second connecting pipe 320. The two opposite ends of the first connecting pipe 310 are respectively connected to the inlet of the vacuum pump 300 and the suction port 110; the two opposite ends of the second connecting pipe 320 are respectively connected to the outlet of the vacuum pump 300 and the air supplement port 130; wherein, a first regulating valve 321 is arranged on the second connecting pipe 320. In this embodiment, by adjusting the first regulating valve 321, on the one hand, the flow rate of the gas sent back into the oil sump is adjusted to keep the pressure in the oil sump within an appropriate pressure range; on the other hand, by adjusting the first regulating valve 321, the vacuum degree generated by the vacuum pump 300 can be adjusted, and further the air flow rate outside the oil sump can be adjusted, so that the sealing effect of the shaft sealing system is adjustable.

[0047] In the embodiment, the first regulating valve 321 can be an electromagnetic flow valve, a manual flow valve, etc.

[0048] As an alternative embodiment of the above embodiment, as Figure 4 shown, the shaft sealing system further includes a third connecting pipe 330 and an oil mist treatment device 400; the third connecting pipe 330 is connected in parallel with the second connecting pipe 320, and the third connecting pipe 330 is communicated with the oil mist treatment device 400; a second regulating valve 331 is arranged on the third connecting pipe 330. In the embodiment, the gas entering the vacuum pump is a mixed gas, which includes the air sucked outside the oil sump and the oil mist gas sucked inside the oil sump. In order to ensure the stability of the oil pressure in the oil sump, by adjusting the second regulating valve 331 and the first regulating valve 321, the flow rate of the oil mist gas entering from the air supplement port 130 is approximately equal to the flow rate of the oil mist gas sucked from inside the oil sump, and the flow rate of the mixed gas discharged from the third connecting pipe 330 is approximately equal to the air sucked from outside the oil sump.

[0049] In the embodiment, the oil mist treatment device 400 is used for separating and recovering the oil mist mixed gas.

[0050] As an alternative implementation of the above embodiment, the shaft sealing system further includes a control component configured to start the vacuum pump 300 and / or adjust the opening degrees of the first regulating valve 321 and the second regulating valve 331. In this embodiment, the control component generally includes a processor and a memory. The memory is configured with a control program, and the processor is configured to call the control program to execute the sealing method provided by the embodiments of the present application. During the operation of the shaft 500, the processor controls the start of the vacuum pump 300 so that the air pressure inside the oil sump and the air pressure outside the oil sump are both lower than the air pressure inside the first annular sealing cavity 120, thereby causing the oil mist inside the oil sump to enter the first annular sealing cavity 120 of the oil baffle body 100.

[0051] In the embodiment, by controlling the opening degrees of the first regulating valve 321 and the second regulating valve, the vacuum degree of the vacuum pump 300 is adjusted, and the gas flow rates inside the second connection pipe 320 and the third connection pipe 330 are adjusted to keep the oil pressure inside the oil sump in a relatively stable state while ensuring the sealing performance.

[0052] The present application also proposes a generator set including a shaft sealing system. The shaft sealing system is used to seal the shaft 500. The shaft sealing system includes the shaft sealing system described in the foregoing embodiment.

[0053] The present application also provides a sealing method for sealing the shaft 500, which is applied to the shaft sealing system as described above. The sealing method includes: starting the vacuum pump 300 to create a vacuum environment in the first annular sealing cavity 120 inside the oil baffle body 100, so that the air pressure inside the oil sump and the air pressure outside the oil sump are both lower than the air pressure in the first annular sealing cavity 120. As a result, the gas outside the oil sump enters the radial gap to form a wind wall, blocking the leakage of the oil sump from the radial gap. In some embodiments, the oil mist inside the oil sump is sucked into the first annular sealing cavity 120 of the oil baffle body 100 and can re-enter the oil sump through the air supply port 130. The sealing plate 200 is at least axially fixed to the oil baffle body 100 and has a second annular sealing cavity 210. The radial gap S communicates with the first annular sealing cavity 120 of the oil baffle body 100 through the second annular sealing cavity 210. The oil baffle body 100 has an air suction port 110 communicating with the first annular sealing cavity 120 and an air supply port 130 communicating with the oil sump. The inlet of the vacuum pump 300 is connected to the air suction port 110, and the outlet of the vacuum pump 300 is connected to the air supply port 130. During operation, the vacuum pump 300 is started to generate a vacuum degree in the first annular sealing cavity 120. Although the first pressure inside the oil sump is greater than the second pressure outside the oil sump, the vacuum degree in the first annular sealing cavity 120 causes the gas outside the oil sump to flow at a high speed into the oil sump in the radial gap S, blocking the outward leakage of the oil mist, and the oil mist can be sucked into the first annular sealing cavity 120 through the second annular sealing cavity 210 together, thus avoiding the leakage of the oil mist.

[0054] The above has introduced in detail an axial sealing system, a generator set and a sealing method provided by the embodiments of the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. At the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A shaft sealing system, characterized in that, Comprising: An oil baffle body, which is annularly arranged around the shaft to be sealed and is used to define an oil groove; A first annular sealing cavity is formed inside the oil baffle body; an air suction port is formed on the oil baffle body, and the air suction port communicates with the first annular sealing cavity; A vacuum pump, which is arranged outside the oil baffle body, and the inlet of the vacuum pump communicates with the air suction port; And A sealing plate, which is annularly arranged around the shaft to be sealed; a radial gap is formed between the sealing plate and the shaft to be sealed; a second annular sealing cavity is formed inside the sealing plate, and the second annular sealing cavity communicates with the radial gap; the sealing plate is at least axially fixed with the oil baffle body, and the first annular sealing cavity communicates with the second annular sealing cavity; a plurality of throttle holes are formed on the sealing plate, and the plurality of throttle holes are arranged at intervals along the circumferential direction of the shaft to be sealed; the second annular sealing cavity communicates with the first annular sealing cavity through the plurality of throttle holes; the sealing plate includes a first sealing tooth and a second sealing tooth respectively located on the two axial sides of the second annular sealing cavity, and the first sealing tooth and the second sealing tooth are arranged at intervals along the axial direction of the shaft to be sealed; wherein, a first radial gap is formed between the first sealing tooth and the shaft to be sealed, and a second radial gap is formed between the second sealing tooth and the shaft to be sealed; a limiting protrusion is formed on the inner wall of the first annular sealing cavity, and the limiting protrusion contacts the sealing plate when the radial width of the radial gap reaches the maximum value, thereby restricting the sealing plate from continuing to move radially away from the shaft to be sealed along the shaft to be sealed.

2. The shaft seal system according to claim 1, characterized in that, A gas supplement port is further arranged on the oil baffle body, and the gas supplement port communicates with the outlet of the vacuum pump; the gas supplement port and the air suction port are arranged at intervals, and the gas supplement port communicates with the oil groove.

3. The shaft seal system according to claim 2, characterized in that, The shaft sealing system includes a first connecting pipe and a second connecting pipe, and the two opposite ends of the first connecting pipe are respectively connected to the inlet of the vacuum pump and the air suction port; the two opposite ends of the second connecting pipe are respectively connected to the outlet of the vacuum pump and the gas supplement port; Wherein, a first regulating valve is arranged on the second connecting pipe.

4. The shaft seal system according to claim 3, characterized in that, The shaft sealing system further includes a third connecting pipe and an oil mist treatment device; the third connecting pipe is connected in parallel with the second connecting pipe, and the third connecting pipe communicates with the oil mist treatment device; a second regulating valve is arranged on the third connecting pipe.

5. The shaft seal system according to claim 4, characterized in that, The shaft sealing system further includes a control component, and the control component is configured to start the vacuum pump and / or adjust the opening degrees of the first regulating valve and the second regulating valve.

6. A generator set, characterized in that, Comprising the shaft sealing system according to any one of claims 1 to 5.

7. A sealing method, characterized in that, Applied to the shaft sealing system according to any one of claims 1 to 5; the sealing method includes: starting the vacuum pump to establish a vacuum environment in the first annular sealing cavity inside the oil baffle body, so that the air pressure inside the oil groove and the air pressure outside the oil groove are both lower than the air pressure inside the first annular sealing cavity, thereby enabling the gas outside the oil groove to enter the radial gap to form a wind wall, blocking the leakage of the oil groove from the radial gap.

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