Flexible seal structure and rotary machine

Abstract

The present application relates to the technical field of sealing, and discloses a flexible sealing structure and a rotary machine. The flexible sealing structure comprises a flexible sealing tooth, a stator and a rotor coaxially arranged in the stator, a first sealing gap is formed between the stator and the rotor, the flexible sealing tooth comprises a flexible sealing part, the flexible sealing part comprises a first sealing part extending vertically and a second sealing part extending downwardly and obliquely from the bottom end of the first sealing part, a groove is formed in the inner circumferential surface of the stator, and the second sealing part can change the included angle with the first sealing part. The second sealing part of the flexible sealing tooth in the present application can change the included angle with the first sealing part under the action of the pressure difference of the working medium, so that the flexible sealing tooth has the self-adapting deformation characteristic, a smaller sealing gap is maintained during the high-pressure operation of the rotary machine, and the flexible sealing tooth elastically retreats to reduce the abrasion between the flexible sealing tooth and the rotor when the rotor has a larger vibration.

Description

Technical Field

[0001] This invention relates to the field of sealing technology, and more specifically to a flexible sealing structure. Based on this, it also relates to a rotating machine. Background Technology

[0002] Dynamic seals are a key component of rotating machinery, used to control the leakage flow of the working fluid through the dynamic-static gap, significantly affecting the operating efficiency and safety of the machinery. Labyrinth seals, due to their simple structure and high reliability, are widely used in centrifugal compressors, steam turbines, turboexpanders, and other rotating machinery. Typically, when the unit is operating stably, labyrinth seals exhibit good sealing performance with their relatively small design clearance.

[0003] However, during the startup, shutdown, hot restart, and changing operating conditions of the unit, the rotor experiences significant vibration. The sealing teeth of the labyrinth seal are prone to rubbing against the rotor, leading to wear of the sealing teeth, increased sealing gap, degradation of sealing performance, and even rotor bending and shaft instability. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem in the prior art where the sealing teeth easily rub against the rotor during rotor vibration, leading to wear of the sealing teeth. This invention provides a flexible sealing structure that has the advantage of reducing wear between the sealing teeth and the rotor.

[0005] To achieve the above objectives, the present invention provides a flexible sealing structure, which includes flexible sealing teeth, a stator, and a rotor coaxially disposed inside the stator. A first sealing gap exists between the stator and the rotor. The flexible sealing teeth include flexible sealing portions, each including a vertically extending first sealing portion and a second sealing portion extending downwardly from the bottom end of the first sealing portion. A groove is formed on the inner circumferential surface of the stator. The first sealing portion is disposed within the groove, and the second sealing portion extends outside the groove and is located within the first sealing gap. The working fluid flows in from one end of the first sealing gap and flows out from the other end. The second sealing portion can be acted to change the included angle with the first sealing portion.

[0006] Optionally, the flexible sealing tooth includes two sets of symmetrically arranged flexible sealing parts, a third sealing part and a sealing wedge respectively disposed in the groove, the third sealing part extending horizontally and connected to the top of the two first sealing parts, and the sealing wedge located in the space surrounded by the first sealing part and the third sealing part.

[0007] Optionally, the flexible sealing tooth includes a set of flexible sealing portions and a third sealing portion and a sealing wedge respectively disposed in the groove. The third sealing portion extends horizontally from the top end of the first sealing portion, and at least part of the sealing wedge is located in the space surrounded by the first sealing portion and the third sealing portion.

[0008] Optionally, the second sealing portion is inclined away from the third sealing portion.

[0009] Optionally, the flexible sealing tooth includes an overlapping sealing plate and a support plate. The sealing plate includes a vertically extending vertical sealing portion, an inclined sealing portion extending downward from the bottom end of the vertical sealing portion, and a horizontally extending horizontal sealing portion extending from the top end of the vertical sealing portion. The support plate includes a vertically extending vertical support portion, an inclined support portion extending downward from the bottom end of the vertical support portion, and a horizontally extending horizontal support portion extending from the top end of the vertical support portion. The vertical sealing portion and the vertical support portion form the first sealing portion, the inclined sealing portion and the inclined support portion form the second sealing portion, and the horizontal sealing portion and the horizontal support portion form the third sealing portion.

[0010] Optionally, the support piece is located on at least one side of the sealing piece facing or away from the sealing wedge.

[0011] Optionally, the sealing sheet includes a sealing tip extending vertically downward from the inclined sealing portion.

[0012] Optionally, a second sealing gap is provided between the bottom of the sealing tip and the outer peripheral surface of the rotor.

[0013] Optionally, the second sealing gap gradually decreases along the flow direction of the working fluid.

[0014] Optionally, a boss is provided on the outer peripheral surface of the rotor, and the second sealing gap is formed between the sealing tip and the boss.

[0015] The present invention also provides a rotating machine comprising the flexible sealing structure described above.

[0016] Through the above technical solution, the second sealing part of the flexible sealing tooth in this invention can change the angle between itself and the first sealing part under the action of working fluid pressure difference. Therefore, the flexible sealing tooth has adaptive deformation characteristics, can adapt to different pressure difference environments, maintain a small sealing gap when rotating machinery is operating under high pressure, and reduce wear between the sealing tooth and the rotor when the rotor has large vibration, thereby achieving a low leakage, long service life, and efficient and safe sealing effect. Attached Figure Description

[0017] Figure 1This is a cross-sectional view of the sealing structure in this invention;

[0018] Figure 2 This is one embodiment of the flexible sealing tooth in this invention;

[0019] Figure 3 This is another embodiment of the flexible sealing tooth in this invention;

[0020] Figure 4 This is another embodiment of the flexible sealing tooth in this invention;

[0021] Figure 5 This is another embodiment of the flexible sealing tooth in this invention;

[0022] Figure 6 This is a schematic diagram of the second sealing gap in this invention.

[0023] Explanation of reference numerals in the attached figures

[0024] 1-Stator; 2-Rotor; 3-Sealing plate; 31-Horizontal sealing part; 32-Vertical sealing part; 33-Inclined sealing part; 34-Sealing tip; 4-Support plate; 41-Horizontal support part; 42-Vertical support part; 43-Inclined support part; 5-Sealing wedge; 6-Groove; 7-Boss; 8-Flexible sealing tooth; 9-Second sealing gap; 11-Third sealing part; 12-First sealing part; 13-Second sealing part. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0026] In this invention, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the orientation shown in the accompanying drawings, and "inner" and "outer" refer to the inner and outer sides relative to the outline of each component itself.

[0027] like Figure 1As shown, the present invention provides a flexible sealing structure, which includes a flexible sealing tooth 8, a stator 1, and a rotor 2 coaxially disposed inside the stator 1. A first sealing gap is provided between the stator 1 and the rotor 2. The flexible sealing tooth 8 includes a flexible sealing portion, which includes a vertically extending first sealing portion 12 and a second sealing portion 13 extending downwardly from the bottom end of the first sealing portion 12. A groove 6 is formed on the inner circumferential surface of the stator 1. The first sealing portion 12 is disposed in the groove 6. The second sealing portion 13 extends to the outside of the groove 6 and is located in the first sealing gap. The working fluid flows in from one end of the first sealing gap and flows out from the other end. The second sealing portion 13 can be acted to change the included angle with the first sealing portion 12.

[0028] Through the above technical solution, the second sealing part 13 of the flexible sealing tooth 8 in this invention can change the angle between itself and the first sealing part 12 under the action of working fluid pressure difference. Therefore, the flexible sealing tooth 8 has adaptive deformation characteristics, can adapt to different pressure difference environments, maintain a small sealing gap when rotating machinery is running under high pressure, and reduce the wear between the sealing tooth and the rotor 2 when the rotor 2 has large vibration, thereby achieving a low leakage, long service life, high efficiency and safety sealing effect.

[0029] like Figure 2 and Figure 3 As shown, in one embodiment of the present invention, the flexible sealing tooth 8 includes two sets of symmetrically arranged flexible sealing portions and a third sealing portion 11 and a sealing wedge 5 respectively disposed in the groove 6. The third sealing portion 11 extends horizontally and connects to the tops of the two first sealing portions 12, and the sealing wedge 5 is located within the space surrounded by the first sealing portions 12 and the third sealing portions 11. In this embodiment, the flexible sealing tooth 8 has a double-tooth structure.

[0030] like Figure 4 and Figure 5 As shown, in another embodiment of the present invention, the flexible sealing tooth 8 includes a set of flexible sealing portions and a third sealing portion 11 and a sealing wedge 5 respectively disposed in the groove 6. The third sealing portion 11 extends horizontally from the top end of the first sealing portion 12, and at least a portion of the sealing wedge 5 is located within the space surrounded by the first sealing portion 12 and the third sealing portion 11. In this embodiment, the flexible sealing tooth 8 has a single-tooth structure.

[0031] In the two embodiments described above, the radial height of the double-tooth flexible sealing tooth 8 is preferably greater than that of the single-tooth flexible sealing tooth 8. The sealing wedge 5 is used to tightly fit the flexible sealing tooth 8, particularly the first sealing portion 12 and the third sealing portion 11, within the groove 6. Furthermore, the second sealing portion 13 is preferably inclined away from the third sealing portion 11.

[0032] In this invention, the flexible sealing tooth 8 includes an overlapping sealing sheet 3 and a support sheet 4. The sealing sheet 3 includes a vertically extending vertical sealing portion 32, an inclined sealing portion 33 extending downward from the bottom end of the vertical sealing portion 32, and a horizontally extending horizontal sealing portion 31 extending from the top end of the vertical sealing portion 32. The support sheet 4 includes a vertically extending vertical support portion 42, an inclined support portion 43 extending downward from the bottom end of the vertical support portion 42, and a horizontally extending horizontal support portion 41 extending from the top end of the vertical support portion 42. The vertical sealing portion 32 and the vertical support portion 42 form the first sealing portion 12, the inclined sealing portion 33 and the inclined support portion 43 form the second sealing portion 13, and the horizontal sealing portion 31 and the horizontal support portion 41 form the third sealing portion 11.

[0033] The support plate 4 may be located on the side of the sealing plate 3 facing the sealing wedge 5, or the support plate 4 may be located on the side of the sealing plate 3 away from the sealing wedge 5, or the support plate 4 may be located on both sides of the sealing plate 3.

[0034] In this invention, by designing the thickness, number of layers, materials, and positional relationship of the sealing sheet 3 and the support sheet 4, as well as the included angle between the second sealing part 13 and the first sealing part 12, the flexible sealing tooth 8 possesses reasonable rigidity and a certain deformation capacity, thereby making the deformation of the flexible sealing tooth 8 controllable under different pressure differential environments. Therefore, the flexible sealing tooth 8 not only ensures a small second sealing gap 9 between the sealing tip 34 and the outer peripheral surface of the rotor 2 during high-pressure operation of rotating machinery, but also reduces wear on the sealing tooth caused by the rotor 2 during conditions of significant vibration, such as when the rotating machinery starts up or stops beyond critical values.

[0035] Furthermore, the sealing plate 3 includes a sealing tip 34 extending vertically downward from the inclined sealing portion 33, and a second sealing gap 9 is formed between the bottom of the sealing tip 34 and the outer peripheral surface of the rotor 2. Figure 6 As shown, the arrows indicate the flow direction of the working fluid, and the pressures are P1>P2>P3. When the rotating machinery is operating under high pressure, the angle between the second sealing part 13 and the first sealing part 12 increases under the influence of the working fluid pressure difference, causing the second sealing gap 9 to decrease, thereby controlling the leakage of the working fluid.

[0036] In such Figure 6In one embodiment of the present invention, when the rotating machinery is running under high pressure and stable conditions, the rotor 2 vibrates less, and there is a large pressure difference between the inlet and outlet of the first sealing gap. The pressure borne by the flexible sealing tooth 8 near the high-pressure inlet is greater than the pressure borne by the flexible sealing tooth 8 near the low-pressure outlet. Therefore, the second sealing part 12 near the high-pressure inlet has greater deformation. Thus, in order to make the sealing effect between the stator 1 and the rotor 2 more consistent, the second sealing gap 9 can be gradually reduced along the flow direction of the working fluid. Specifically, in this embodiment, the flexible sealing tooth 8 is a double-tooth structure. In the two second sealing gaps 9 formed by the bottom of the sealing tip 34 of the double-tooth structure and the outer peripheral surface of the rotor 2, the cold-state design value of the second sealing gap 9 near the high-pressure inlet is greater than the cold-state design value of the second sealing gap 9 near the low-pressure outlet. Here, the cold-state design value refers to the design value of the rotating machinery in a stationary state when it is not turned on.

[0037] In another embodiment of the present invention, a boss 7 is provided on the outer peripheral surface of the rotor 2, and the second sealing gap 9 is formed between the sealing tip 34 and the boss 7. Specifically, in this embodiment, the flexible sealing tooth 8 can be a single-tooth structure. The flexible sealing tooth 8 of the single-tooth structure preferably has a large second sealing gap 9 with the outer peripheral surface of the boss 7. When a sudden short-term limit vibration occurs during the operation of the rotating machinery, and the flexible sealing tooth 8 rubs against the outer peripheral surface of the rotor 2, the flexible sealing tooth 8, under the radial force of the rotor 2, causes the included angle between the second sealing part 13 and the first sealing part 12 to decrease. Thus, the flexible sealing tooth 8 has a certain elastic yielding (elastic deformation) capability, which can reduce the damage to the flexible sealing tooth 8 and the rotor 2 caused by the rubbing. In other words, when the rotor 2 has large vibration, even if the rotor 2 collides with the flexible sealing tooth 8, the collision cannot cause significant damage to the flexible sealing tooth 8 because the flexible sealing tooth 8 has good elastic deformation capability.

[0038] The present invention also provides a rotating machine comprising the aforementioned sealing structure. The rotating machine of the present invention and the aforementioned sealing structure possess the same advantages over the prior art, and will not be repeated here. It is understood that the rotating machine can be at least one of a centrifugal compressor, a steam turbine, or a turboexpander.

[0039] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately. However, these simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A flexible sealing structure, characterized in that, The flexible sealing structure includes a flexible sealing tooth (8), a stator (1), and a rotor (2) coaxially inserted inside the stator (1). There is a first sealing gap between the stator (1) and the rotor (2). The flexible sealing tooth (8) includes a flexible sealing part, which includes a vertically extending first sealing part (12) and a second sealing part (13) extending downward from the bottom end of the first sealing part (12). A groove (6) is formed on the inner circumferential surface of the stator (1). The first sealing part (12) is disposed in the groove (6). The second sealing part (13) extends to the outside of the groove (6) and is located in the first sealing gap. The working fluid flows in from one end of the first sealing gap and flows out from the other end. The second sealing part (13) can be used to change the angle between itself and the first sealing part (12). The flexible sealing tooth (8) includes two sets of symmetrically arranged flexible sealing parts and a third sealing part (11) and a sealing wedge (5) respectively disposed in the groove (6). The third sealing part (11) extends horizontally and is connected to the top of the two first sealing parts (12). The sealing wedge (5) is located in the space surrounded by the first sealing part (12) and the third sealing part (11). The flexible sealing tooth (8) includes a set of flexible sealing parts and a third sealing part (11) and a sealing wedge (5) respectively disposed in the groove (6). The third sealing part (11) extends horizontally from the top end of the first sealing part (12), and at least part of the sealing wedge (5) is located in the space surrounded by the first sealing part (12) and the third sealing part (11). The flexible sealing tooth (8) includes an overlapping sealing plate (3) and a support plate (4). The sealing plate (3) includes a vertically extending vertical sealing portion (32), an inclined sealing portion (33) extending downward from the bottom end of the vertical sealing portion (32), a horizontally extending horizontal sealing portion (31) extending from the top end of the vertical sealing portion (32), and a sealing tip (34) extending downward from the inclined sealing portion (33). The bottom of the sealing tip (34) has a second sealing gap (9) between it and the outer peripheral surface of the rotor (2). When the flexible sealing tooth (8) includes two sets of symmetrically arranged flexible sealing parts, the second sealing gap (9) gradually decreases along the flow direction of the working fluid; and when the flexible sealing tooth (8) includes a set of flexible sealing parts, a boss (7) is provided on the outer peripheral surface of the rotor (2), and the second sealing gap (9) is formed between the sealing tip (34) and the boss (7).

2. The flexible sealing structure according to claim 1, characterized in that, The second sealing part (13) is inclined away from the third sealing part (11).

3. The flexible sealing structure according to claim 1, characterized in that, The support plate (4) includes a vertically extending vertical support portion (42), an inclined support portion (43) extending downward from the bottom end of the vertical support portion (42), and a horizontal support portion (41) extending horizontally from the top end of the vertical support portion (42). The vertical sealing part (32) and the vertical support part (42) form the first sealing part (12), the inclined sealing part (33) and the inclined support part (43) form the second sealing part (13), and the horizontal sealing part (31) and the horizontal support part (41) form the third sealing part (11).

4. The flexible sealing structure according to claim 3, characterized in that, The support piece (4) is located on at least one side of the sealing piece (3) facing or away from the sealing wedge (5).

5. A rotating machine, characterized in that, The rotating machinery includes a flexible sealing structure according to any one of claims 1-4.

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