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 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; an annular notch is formed on the oil baffle body; 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; a plurality of sealing plates which are arranged in the annular notch, and the plurality of sealing plates are annularly arranged around the shaft in the circumferential direction of the shaft; a second annular sealing cavity is formed inside each sealing plate, and the second annular sealing cavity is communicated with the first annular sealing cavity; the plurality of sealing plates are configured to be movable in the oil baffle body along the radial direction of the shaft, so that a radial gap can be formed between the plurality of sealing plates and the shaft, and the radial gap is communicated with the second annular sealing cavity. The present application aims to solve the technical problem that the sealing structure is excessively worn, thereby resulting in sealing failure.

Description

Technical Field

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

[0002] The oil mist of a water turbine unit comes from the bearing. When the unit is operating, the shaft rotates to stir the oil in the oil sump, thereby generating bubbles. The operation of the bearing and the agitation of the rotating components generate heat, which accelerates the formation of bubbles in the oil. When the bubbles burst, oil mist is generated. 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 two 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] The present application provides a shaft sealing system, a generator set and a sealing method, aiming to solve the technical problem that in the prior art, due to the high-speed rotation of the shaft, there is mutual friction between the shaft and the sealing structure, resulting in excessive wear of the sealing structure and subsequent sealing failure.

[0004] The present application proposes a shaft sealing system for sealing a shaft, comprising:

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

[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;

[0007] A plurality of sealing plates, which are arranged in the annular notch and are arranged around the shaft to be sealed in the circumferential direction of the shaft to be sealed; a second annular sealing cavity is formed inside each sealing plate, and the second annular sealing cavity is communicated with the first annular sealing cavity; wherein, the plurality of sealing plates are configured to be movable in the radial direction of the shaft to be sealed, so that a radial gap can be formed between the plurality of sealing plates and the shaft to be sealed, and the radial gap is communicated with the second annular sealing cavity.

[0008] Optionally, an adjustment hole is provided on the oil baffle body; the shaft sealing system further comprises an adjustment mechanism, and the adjustment mechanism comprises an adjustment rod, an adjustment nut and a locking nut;

[0009] The adjusting rod has a first end and a second end that are arranged opposite to each other and an intermediate body located between the first end and the second end; at least a portion of the intermediate body is arranged in the adjusting hole; the first end is connected to the sealing plate; at least a portion of the adjusting nut is located on the outside of the oil baffle body, and the other portion is detachably engaged with the adjusting hole; the second end has a threaded section, the adjusting nut and the locking nut are both engaged with the threaded section, and the locking nut is located on the outside of the oil baffle body and in contact with the adjusting nut.

[0010] Optionally, the sealing plate has a receiving hole and a first limiting hole connected to the receiving hole; the adjusting mechanism also includes a limiting member, a sleeve and a spring; the first end extends into the receiving hole; the first end is provided with a second limiting hole connected to the first limiting hole; the limiting member is at least partially tightly fitted with the first limiting hole, and the other part is arranged in the second limiting hole and maintains a space with the second limiting hole in the axial direction of the receiving hole, so that the sealing plate and the adjusting rod are connected in a relative motion manner; the sleeve is arranged in the oil baffle body and has a through hole connected to the adjusting hole; at least another part of the intermediate body is also pierced by the through hole; one end of the spring abuts against the side of the sealing plate away from the sealed shaft, and the other end abuts against the sleeve.

[0011] Optionally, the sealing plate has a groove whose opening is arranged on the axial end face of the sealing plate; the shaft sealing system also includes a filler; the filler is arranged in the groove and contacts the oil baffle body; before the sealed shaft runs, the sealing plate abuts the sealed shaft; when the sealed shaft runs, under the action of the radial force of the sealed shaft, the sealing plate overcomes the friction between the filler and the oil baffle body and runs radially away from the sealed shaft to form the radial gap.

[0012] Optionally, an adjustment hole is provided on the oil baffle body, and the adjustment hole is arranged corresponding to the sealing plate; the shaft sealing system also includes a plug; the plug is provided in each of the adjustment holes, and the plug is configured to have a blocked state for blocking the adjustment hole corresponding to the adjustment hole and a non-blocked state for disengaging from the adjustment hole corresponding to the adjustment hole.

[0013] Optionally, each of the sealing plates further has a throttling hole, and the second annular sealing cavity is connected to the first annular sealing cavity through the throttling hole.

[0014] Optionally, each of the sealing plates includes a first sealing tooth and a second sealing tooth respectively 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, the first sealing tooth is configured to form a first radial gap with the sealed shaft when the sealing plate moves radially relative to the sealed shaft, and the second sealing tooth forms a second radial gap with the sealed shaft when the sealing plate moves radially relative to the sealed shaft.

[0015] Optionally, an air supplement port is arranged on the oil baffle body, the air supplement port and the air suction port are arranged at an interval and communicated with the oil sump; the shaft sealing system includes a first connecting pipe, a second connecting pipe, a third connecting pipe and an oil mist treatment device, 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; the third connecting pipe is connected in parallel with the second connecting pipe and communicated with the oil mist treatment device; wherein, a first regulating valve is arranged on the second connecting pipe, and a second regulating valve is arranged on the third connecting pipe.

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

[0017] The present application also provides a sealing method applied to the shaft sealing system as described above; the sealing method includes: adjusting the radial positions of the plurality of sealing plates so that there are radial gaps between the plurality of sealing plates and the sealed shaft when the sealed shaft is operating; starting the vacuum pump to create 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, and then the air outside the oil sump enters the radial gap to form a wind wall to block the oil mist in the oil sump from leaking from the radial gap.

[0018] In the technical solution of the embodiment of the present application, on the one hand, by arranging a plurality of sealing plates in the annular notch of the oil baffle body, the plurality of sealing plates are arranged in a circle around the shaft in the circumferential direction of the shaft; each of the plurality of sealing plates has a second annular sealing cavity communicated with the first annular sealing cavity; the plurality of sealing plates are configured to be able to move radially relative to the shaft, and further the plurality of sealing plates can form a radial gap with the shaft, and the radial gap is communicated with the second annular sealing cavity. When the vacuum pump is started, the second annular sealing cavity and the first annular sealing cavity are in a vacuum environment, and their pressures are lower than the pressure outside the oil sump. Therefore, the gas outside the oil sump will flow towards the inner side of the oil sump through the radial gap under the action of the pressure difference to form a wind wall to block the oil mist from flowing out of the radial gap. Therefore, it can ensure reliable sealing while the oil mist will not leak from the sealing gap.

[0019] On the other hand, each sealing plate can move along the radial direction of the shaft, so the size of the radial clearance can be adjusted. The adjustment of the radial clearance can be adaptive or adjusted by an adjusting mechanism. The shaft moves relative to the sealing plate during operation, and this movement mainly includes two parts, one part is high-speed vibration and the other part is slow movement. During adaptive adjustment, the sealing plate is pushed open by the radial force of the shaft during the interaction with the shaft to form a radial clearance; this radial clearance is the minimum clearance that can be obtained under the condition of ensuring that the seal does not wear. The adjusting mechanism adjusts the radial movement of the sealing plate to adapt to the movement of the shaft relative to the sealing plate to form a radial clearance, so that there is a radial clearance between the sealing plate and the shaft before the shaft operates. Brief Description of the Drawings

[0020] 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.

[0021] Figure 1 is a schematic diagram of a prior art seal away;

[0022] Figure 2 is a schematic structural diagram of a shaft seal system in an embodiment of the present application;

[0023] Figure 3 is Figure 2 a partial enlarged view at A in

[0024] Figure 4 is an assembly structural diagram of a sealing plate and an adjusting structure in an embodiment of the present application;

[0025] Figure 5 is another schematic structural diagram of a shaft seal system in an embodiment of the present application;

[0026] Figure 6 is a schematic structural diagram of an oil baffle body in a shaft seal system in an embodiment of the present application;

[0027] Figure 7 is a schematic diagram of a vacuum pump circulation structure in a shaft seal system in an embodiment of the present application.

[0028]

[0029] Detailed Embodiments

[0030] 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 of 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.

[0031] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It 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 therefore cannot be understood as a limitation of 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 indicating 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.

[0032] In this application, the term "exemplary" is used to mean "serving as an example, illustration, or description". Any embodiment described as "exemplary" in this application is not necessarily to be construed as more preferred or advantageous than other embodiments. The following description is given to enable any person skilled in the art to make and use the present invention. In the following description, details are set forth for the purpose of explanation. It should be understood by those skilled in the art that the present invention can be implemented without 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.

[0033] Refer to Figure 1 as shown, Figure 1 illustrates the shaft-sealing structure-bearing system of a water turbine unit. The bearing system is arranged in the oil sump S3 defined by the sealing 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.

[0034] The structure of the contact seal includes an oil baffle body 100'. Sealing teeth are provided on the oil baffle body 100'. The sealing teeth are abutted against the shaft 500' by 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 has the deficiency of seal failure due to wear.

[0035] The structure of the brush seal is a structure formed by improving the structure of the contact seal. It replaces the structure of the springs and the sealing teeth with brushes. 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 brushes and the shaft 500', wear and hair shedding occur. Wear will cause seal failure. And hair shedding is also prone to the phenomenon that the hair debris enters the oil sump S3 and causes pollution to the oil. Further, the hair debris enters the oil film with the oil and is very likely to damage the bearing bush.

[0036] Therefore, the embodiment of the present application proposes a non-contact shaft seal system with adjustable seal clearance, aiming at that when the shaft contacts the seal structure, the seal structure can adaptively adjust its seal clearance with the shaft or the adjustment mechanism adjusts the seal clearance between the seal structure and the shaft, so as to reduce the wear of the seal structure while ensuring reliable sealing.

[0037] Combined with Figure 2 、 Figure 6 and Figure 7 As shown, the shaft seal system of the embodiment of the present application includes an oil baffle body 100, a vacuum pump 300 and a sealing plate 200. There are multiple sealing plates 200. Each sealing plate 200 has the same size. After the multiple sealing plates 200 are assembled, a 360° annular structure is formed.

[0038] Wherein, the oil baffle body 100 is arranged around the shaft 500 to be sealed for defining an oil sump. In the following embodiments, for the convenience of description, the shaft 500 to be sealed is expressed as the shaft. A bearing assembly is arranged in the oil sump for supporting the shaft 500. The oil baffle body 100 has a first annular seal cavity 120 inside; an air suction port 110 is opened on the oil baffle body 100, and the air suction port 110 is communicated with the first annular seal cavity 120; an annular notch 150 is provided on the oil baffle body 100;

[0039] Wherein, the vacuum pump 300 is arranged outside the oil baffle body 100, and the inlet of the vacuum pump 300 is communicated with the air suction port 110;

[0040] A plurality of sealing plates 200 are arranged in the annular notch 150, and the plurality of sealing plates 200 surround the sealed shaft 500 in a circle in the circumferential direction of the sealed shaft 500; each of the sealing plates 200 has a second annular sealing cavity 210 therein, and the second annular sealing cavity 210 communicates with the first annular sealing cavity 120; wherein, the plurality of sealing plates 200 are configured to be movable in the radial direction of the sealed shaft 500, so that a radial gap S can be formed between the plurality of sealing plates 200 and the sealed shaft 500, and the radial gap S communicates with the second annular sealing cavity 210.

[0041] In the technical solution of the embodiment of the present application, by arranging a plurality of sealing plates 200 in the annular notch 150 of the oil baffle body 100, the plurality of sealing plates 200 surround the shaft 500 in a circle in the circumferential direction of the shaft 500; each of the plurality of sealing plates 200 has a second annular sealing cavity 210 communicating with the first annular sealing cavity 120; the plurality of sealing plates 200 are configured to be movable in the radial direction of the shaft 500, and further, the plurality of sealing plates 200 can form a radial gap S with the shaft 500, and the radial gap S communicates with the second annular sealing cavity 210. When the vacuum pump 300 is started, the second annular sealing cavity 210 and the first annular sealing cavity 120 are in a vacuum environment, and their pressures are lower than the pressure outside the oil sump. Therefore, the gas outside the oil sump will flow towards the inner side of the oil sump through the radial gap S under the action of the pressure difference to form a wind wall to block the oil mist from flowing out through the radial gap S. Therefore, while ensuring reliable sealing, the oil mist will not leak from the sealing gap.

[0042] Since in the technical solution of the embodiment of the present application, each sealing plate 200 can move along the radial direction of the shaft 500, the size of the radial gap S can be adjusted. The adjustment of the radial gap S can be adaptive or can be adjusted by an adjusting mechanism. When the shaft 500 is running, it is in motion relative to the sealing plate 200. This motion mainly includes two parts, one part is high-speed vibration, and the other part is slow radial movement. During adaptive adjustment, the sealing plate 200 is pushed open by the radial force of the shaft 500 during the interaction with the shaft 500 to form a radial gap S; the radial gap S is the minimum gap that can be obtained under the condition of ensuring that the seal is not worn. The adjusting mechanism adjusts the radial movement of the sealing plate 200 to adapt to the movement of the shaft 500 relative to the sealing plate 200 to form a radial gap S, so that there is a radial gap S between the sealing plate 200 and the shaft 500 before the shaft 500 runs.

[0043] Furthermore, it should be noted that the technical solution proposed in the embodiment of the present application is generally applicable to large units, that is, the shaft diameter of the shaft 500 to be sealed is relatively large.

[0044] In the following embodiments, an adjusting mechanism for adjusting the radial clearance S between the sealing plate 200 and the shaft 500 and a structure for adaptively adjusting the radial clearance S of the technical solution of the present application are introduced respectively.

[0045] First, the adjusting mechanism is introduced as Figures 2 to 4 shown.

[0046] As an alternative embodiment of the above embodiment, an adjusting hole is provided on the oil baffle body 100; the shaft sealing system further includes an adjusting mechanism, and the adjusting mechanism includes an adjusting rod 620, an adjusting nut 630 and a locking nut 650; the adjusting rod 620 has a first end and a second end disposed opposite to each other and an intermediate body located between the first end and the second end; at least a part of the intermediate body is disposed in the adjusting hole; the first end is connected to the sealing plate 200; at least a part of the adjusting nut 630 is located outside the oil baffle body 100, and the other part is detachably engaged with the adjusting hole; the second end has a threaded section, both the adjusting nut 630 and the locking nut 650 are engaged with the threaded section, and the locking nut 650 is located outside the oil baffle body 100 and is in contact with the adjusting nut 630. In the embodiment, when it is necessary to adjust the radial clearance S, by loosening the locking nut 650 and by operating the part of the adjusting nut 630 located outside the oil baffle body 100 to release the connection relationship between the adjusting nut 630 and the oil baffle body 100, at this time, the adjusting rod 620 can be pulled or pushed to drive the sealing plate 200 to move radially relative to the shaft, thereby adjusting the clearance; when the radial clearance S is adjusted, the adjusting nut 630 is re-engaged with the oil baffle body 100, and the locking nut 650 is tightened to lock the adjusting nut 630 to prevent loosening.

[0047] In some embodiments, the sealing plate 200 can be fixedly connected to the adjusting rod 620. At this time, after the radial clearance S is adjusted in place and the adjusting nut 630 is locked, the radial clearance S between the sealing plate 200 and the shaft 500 can be changed. In order to reduce the wear of the sealing plate 200, generally, the radial clearance S needs to be adjusted relatively large.

[0048] In some embodiments, the sealing plate 200 can be movably connected to the adjusting rod 620. At this time, after the adjusting nut 630 is locked, the radial clearance S between the sealing plate 200 and the shaft 500 can be adaptively adjusted according to the position of the shaft 500. The sealing plate 200 has a receiving hole 270 and a first limiting hole communicating with the receiving hole 270. The axis of the receiving hole 270 is parallel to the radial direction of the shaft 500 to be sealed. The adjusting mechanism further includes a limiting member 640, a sleeve, and a spring 610. The first end extends into the receiving hole 270. A second limiting hole 621 communicating with the first limiting hole is provided at the first end. At least a part of the limiting member 640 is tightly fitted with the first limiting hole, and the other part is disposed in the second limiting hole 621 and is spaced apart from the second limiting hole 621 in the axial direction of the receiving hole 270, so that the sealing plate 200 and the adjusting rod 620 are connected in a relatively movable manner. The sleeve is disposed in the oil baffle body 100 and has a perforation communicating with the adjusting hole. At least another part of the intermediate body also passes through the perforation. One end of the spring 610 abuts against the side of the sealing plate 200 facing away from the shaft 500 to be sealed, and the other end abuts against the sleeve. In this embodiment, when the radial position of the shaft 500 changes and touches the sealing plate 200, the sealing plate 200 is subjected to a radial pressure. At this time, since there is a gap in the radial direction of the shaft diameter between the limiting member 640 and the second limiting hole 621, the sealing plate 200 can move away from the shaft 500 relative to the adjusting rod 620, and the radial clearance S can be adaptively adjusted. When the sealing plate 200 moves away from the shaft in the radial direction, the spring 610 is compressed, which can play a role in shock absorption and prevent the adjusting nut 630 from loosening.

[0049] The following introduces the adaptive radial clearance S adjusting structure, as Figure 5 shown.

[0050] As an alternative implementation of the above embodiment, the sealing plate 200 has a groove located at the axial end face of the sealing plate 200 where the opening is provided; the shaft sealing system further includes a filler 280; the filler 280 is disposed in the groove and contacts the oil baffle body 100; before the sealed shaft 500 operates, the sealing plate 200 abuts against the sealed shaft 500; when the sealed shaft 500 operates, under the action of the radial force of the sealed shaft 500, the sealing plate 200 overcomes the frictional force between the filler 280 and the oil baffle body 100 and moves radially away from the sealed shaft 500 to form the radial gap S. In the embodiment, during installation, multiple sealing plates 200 all abut against the shaft 500; when the shaft 500 starts to operate, the slow radial movement of the shaft 500 squeezes the sealing plate 200 to form the radial gap S, and this radial gap S is adaptively formed during the operation of the shaft 500 and is the minimum gap that can be obtained under the condition of ensuring no wear of the seal. It should be noted that when the shaft 500 is operating, it is supported by the shaft bearing, so the radial movement amount of the shaft is very small and limited. Therefore, the radial gap S formed by squeezing the sealing plate 200 is relatively small.

[0051] In the embodiment, the provided filler 280 can be a structure with certain damping such as felt. The purpose of setting the filler 280 is to prevent the sealing plate 200 from moving too large radially when being impacted, resulting in an excessive radial gap S.

[0052] As an alternative implementation of the above embodiment, the oil baffle body 100 is provided with adjustment holes corresponding to the sealing plate 200; the shaft sealing system further includes plugs 140; the plugs 140 are disposed in the adjustment holes, and the plugs 140 are configured to have a blocking state of blocking the corresponding adjustment holes and a non-blocking state of being disengaged from the corresponding adjustment holes. During operation, the plugs 140 block the adjustment holes to prevent oil mist from leaking through the adjustment holes; during maintenance and repair, the implementer can take out the plugs 140 from the adjustment holes, extend the push rod through the adjustment holes into the oil baffle body 100, and act on the sealing plate 200 to abut the sealing plate 200 against the shaft 500, so that after maintenance, the sealing plate 200 can adaptively re-form the radial gap S under the action of the shaft 500.

[0053] As an alternative implementation of the above embodiment, such as Figure 2 and Figure 5As shown, the sealing plate 200 includes a first sealing tooth 230 and a second sealing tooth 240 respectively located on both axial sides of the second annular sealing cavity 210 with respect to the shaft 500. The first sealing tooth 230 and the second sealing tooth 240 are arranged at an axial interval along the shaft 500 of the shaft to be sealed. Among them, the first sealing tooth 230 is farther from the oil groove than the second sealing tooth 240. When the sealing plate 200 where the first sealing tooth 230 is located moves, there is a first radial gap S1 between the first sealing tooth 230 and the shaft 500 to be sealed, and there is a second radial gap S2 between the second sealing tooth 240 and the shaft 500 when the sealing plate 200 moves. Air outside the oil groove is sucked in through the first radial gap S1 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 second radial gap S2. In the embodiment, the first sealing teeth 230 of multiple sealing plates form a circumferential integral structure around the shaft 500 after combination; the second sealing teeth 240 of multiple sealing plates form a circumferential integral structure around the shaft 500 after combination.

[0054] In the embodiment, a first wear-resistant layer 250 can be provided on the side of the first sealing tooth 230 facing the shaft; a second wear-resistant layer 260 can be provided on the side of the second sealing tooth 240 facing the shaft.

[0055] During the operation of the shaft 500, there are irregular vibrations. Therefore, during the operation, the size of the radial gap S is dynamically changing and is uneven in the circumferential direction; and the volume of the second annular sealing cavity 210 is limited, and the pressure in the second annular sealing cavity 210 is also uneven in the circumferential direction; for this reason, in order to effectively solve this technical problem and make the pressure everywhere as uniform as possible; referring to Figure 4 As shown, as an alternative implementation manner 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 to be sealed. The second annular sealing cavity 210 communicates with the first annular sealing cavity 120 through the throttle holes 220. By providing throttle holes 220 on the sealing plate 200; the throttle holes 220 adjust the flow rate of the air flow through the pressure difference between the second annular sealing cavity 210 and the first annular sealing cavity 120. Furthermore, although the pressure of the second annular sealing cavity 210 is uneven everywhere, under the action of the throttle holes 220, the gas flow rate is made as uniform as possible, overcoming the technical problem of uneven gas flow rate caused by the irregular vibration of the shaft 500.

[0056] 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, as Figure 6As 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.

[0057] As an alternative implementation of the above embodiment, as Figure 7 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 can be adjusted.

[0058] In the embodiment, the first regulating valve 321 can be an electromagnetic flow valve, a manual flow valve, etc.

[0059] As an alternative implementation of the above embodiment, as Figure 7 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 inhaled outside the oil sump and the oil mist gas inhaled 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 inhaled 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 inhaled from outside the oil sump.

[0060] In the embodiment, the oil mist treatment device 400 is used for separating and recovering the oil mist mixed gas.

[0061] As an alternative embodiment of the above embodiment, the shaft seal 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 seal cavity 120, thereby enabling the oil mist inside the oil sump to enter the first annular seal cavity 120 of the oil baffle body 100.

[0062] 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 connecting pipe 320 and the third connecting pipe 330 are adjusted, so as to keep the oil pressure inside the oil sump in a relatively stable state while ensuring the sealing performance.

[0063] The present application also provides a generator set including a shaft seal system. The shaft seal system is used to seal the shaft 500. The shaft seal system includes the shaft seal system described in the foregoing embodiment. The generator set is especially a large generator set.

[0064] The present application also provides a sealing method applicable to the shaft sealing system described above; the sealing method includes: adjusting the radial positions of the plurality of sealing plates 200 so that there is a radial gap S between the plurality of sealing plates 200 and the shaft 500 to be sealed when the shaft 500 to be sealed is operating; starting a vacuum pump 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 inside the first annular sealing cavity 120. Then, the air outside the oil sump enters the radial gap S to form a wind wall to block the oil mist in the oil sump from leaking through the radial gap S. In the technical solution of the embodiment of the present application, a plurality of sealing plates 200 are arranged in the annular notch of the oil baffle body 100, and the plurality of sealing plates 200 are arranged around the shaft 500 in a circumferential direction of the shaft 500; each of the plurality of sealing plates 200 has a second annular sealing cavity 210 communicated with the first annular sealing cavity 120; the plurality of sealing plates 200 are configured to be movable in the radial direction of the shaft 500, and thus the plurality of sealing plates 200 can form a radial gap S with the shaft 500, and the radial gap S is communicated with the second annular sealing cavity 210. When the vacuum pump is started, the second annular sealing cavity 210 and the first annular sealing cavity 120 are in a vacuum environment, and their pressures are lower than the pressure outside the oil sump. Therefore, the gas outside the oil sump will flow towards the inner side of the oil sump through the radial gap S under the action of the pressure difference to form a wind wall to block the oil mist from flowing out through the radial gap S. Therefore, it can ensure reliable sealing while preventing the oil mist from leaking from the sealing gap.

[0065] In the technical solution of the embodiment of the present application, since each sealing plate 200 can move along the radial direction of the shaft 500, the size of the radial gap S can be adjusted. The adjustment of the radial gap S can be adaptive or adjusted by an adjusting mechanism. When the shaft 500 is operating, it moves relative to the sealing plate 200, and this movement mainly includes two parts, one part is high-speed vibration, and the other part is slow movement. During adaptive adjustment, the sealing plate 200 is pushed open by the radial force of the shaft 500 during the interaction with the shaft 500 to form a radial gap S; the radial gap S is the minimum gap that can be obtained under the condition of ensuring that the seal is not worn. The adjusting mechanism adjusts the radial movement of the sealing plate 200 to adapt to the movement of the shaft 500 relative to the sealing plate 200 to form a radial gap S, so that there is a radial gap S between the sealing plate 200 and the shaft 500 before the shaft 500 operates.

[0066] The above has introduced in detail an axial seal system, a generator set and a sealing method provided by the embodiments of the present application. Specific examples are used herein 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 of the present invention and its core idea; 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, include: an oil baffle body, the oil baffle body being arranged around the sealed shaft and used for defining an oil outlet groove; The oil baffle body has a first annular sealed cavity inside; the oil baffle body has an air intake port, which is connected to the first annular sealed cavity; the oil baffle body is also provided with an annular notch; a vacuum pump, the vacuum pump being arranged on a side of the oil baffle body facing away from the sealed shaft, the inlet of the vacuum pump being communicated with the air intake port; a plurality of sealing plates, the plurality of sealing plates being disposed in the annular notch and being arranged around the sealed shaft; each of the sealing plates having a second annular sealing cavity therein, the second annular sealing cavity being in communication with the first annular sealing cavity; wherein the plurality of sealing plates are configured to be movable in a radial direction of the sealed shaft such that radial gaps are formed between the plurality of sealing plates and the sealed shaft, the radial gaps being in communication with the second annular sealing cavity; The oil baffle body is provided with an adjustment hole; the shaft sealing system further comprises an adjustment mechanism, which comprises an adjustment rod, an adjustment nut and a locking nut; The adjusting rod comprises a first end and a second end which are arranged opposite to each other, and an intermediate body located between the first end and the second end; at least a portion of the intermediate body is disposed in the adjusting hole; the first end is connected to the sealing plate; at least a portion of the adjusting nut is located outside the oil baffle body, and another portion is detachably engaged with the adjusting hole; the second end comprises a threaded section, the adjusting nut and the locking nut both engage with the threaded section, and the locking nut is located outside the oil baffle body and contacts the adjusting nut; The sealing plate has a receiving hole and a first limiting hole communicating with the receiving hole, wherein the axial direction of the receiving hole is parallel to the radial direction of the sealed shaft; the adjusting mechanism further includes a limiting member, a sleeve and a spring; The first end extends into the accommodating hole; the first end is provided with a second limiting hole communicating with the first limiting hole; the limiting member is at least partially tightly fitted with the first limiting hole, and the other portion is provided in the second limiting hole and is spaced apart from the second limiting hole in the axial direction of the accommodating hole, so that the sealing plate and the adjusting rod are connected in a relative motion manner; The sleeve is arranged in the oil baffle body and has a through hole communicating with the adjustment hole; at least another part of the intermediate body is also penetrated by the through hole; one end of the spring abuts against the side of the sealing plate away from the sealed shaft, and the other end abuts against the sleeve.

2. The shaft seal system according to claim 1, wherein The sealing plate has a groove with an opening provided on the axial end surface of the sealing plate; the shaft sealing system further comprises a filler; the filler is provided in the groove and contacts the oil baffle body; Before the sealed shaft runs, the sealing plate abuts against the sealed shaft; when the sealed shaft runs, under the action of the radial force of the sealed shaft, the sealing plate overcomes the friction between the filler and the oil baffle body and runs radially away from the sealed shaft to form the radial gap.

3. The shaft seal system according to claim 2, wherein The oil baffle body is further provided with adjustment holes corresponding to the sealing plates; the shaft sealing system further includes plugs; the plugs are arranged in the adjustment holes, and the plugs are configured to have a sealing state of sealing the corresponding adjustment holes and a non-sealing state of disengaging from the corresponding adjustment holes.

4. The shaft seal system according to claim 1, characterized in that, Each of the sealing plates further has a throttling hole, and the second annular sealing cavity is communicated with the first annular sealing cavity through the throttling hole.

5. The shaft seal system according to claim 1, characterized in that, Each of the sealing plates includes a first sealing tooth and a second sealing tooth respectively located on the axial two 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, the first sealing tooth is configured to form a first radial gap with the shaft to be sealed when the sealing plate moves radially relative to the shaft to be sealed, and the second sealing tooth is configured to form a second radial gap with the shaft to be sealed when the sealing plate moves radially relative to the shaft to be sealed.

6. The shaft seal system according to claim 1, characterized in that, The oil baffle body is further provided with an air inlet, and the air inlet and the air suction port are arranged at intervals and communicated with the oil sump. The shaft sealing system includes a first connecting pipe, a second connecting pipe, a third connecting pipe and an oil mist treatment device. 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 air inlet. The third connecting pipe is connected in parallel with the second connecting pipe and communicated with the oil mist treatment device. Wherein, a first regulating valve is arranged on the second connecting pipe, and a second regulating valve is arranged on the third connecting pipe.

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

8. A sealing method for sealing a shaft, characterized in that, Applied to the shaft sealing system according to any one of claims 1 to 6; the sealing method includes: Adjusting the radial positions of the plurality of sealing plates so that when the shaft to be sealed rotates, a radial gap is formed between the plurality of sealing plates and the shaft to be sealed. 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, and then the air outside the oil sump enters the radial gap to form a wind wall to block the oil mist in the oil sump from leaking through the radial gap.

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