Dry gas seal assembly and vacuum pump

Abstract

The utility model provides a dry gas sealing assembly and a vacuum pump, and relates to the technical field of sealing. Specifically, the dry gas seal assembly comprises a fixed seat, an elastic element, a rotating ring and a fixed ring. Wherein the fixing seat is provided with a containing cavity, and the elastic element, the rotating ring and the fixing ring are all located in the containing cavity. And the fixed ring is positioned between the rotating ring and the elastic element. The elastic element comprises a ring part and at least two elastic parts arranged on the ring part at intervals in the circumferential direction, and the fixed ring is used for being close to the rotating ring under the action of the elastic parts. On the basis, the fixed ring and the rotating ring always have a tendency of being attached together. On the basis, a plurality of spiral air guide grooves are formed in the side, close to the elastic part, of the rotating ring at intervals in the circumferential direction, and the spiral air guide grooves form an air film with certain rigidity by accurately controlling the path and pressure of airflow, so that effective sealing is achieved, fluid media are prevented from leaking, meanwhile, friction loss is reduced, and the service life is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to the sealed technical field, specifically, relate to a dry gas seal assembly and vacuum pump. BACKGROUND

[0002] In the technical field of vacuum pump, radial seal is one of the key technologies to ensure the isolation of pump cavity and the outside world and maintain the required vacuum degree. According to the prior art, the radial seal of moving parts mainly adopts two ways: gap seal and elastic material contact seal.

[0003] However, gap seal cannot achieve complete sealing, and a small amount of gas will always leak from the gap, thereby affecting the stability of the vacuum degree; due to long-term friction, the elastic material will gradually wear out in practical application, resulting in a decline in sealing effect and ultimately losing its sealing ability. SUMMARY

[0004] The utility model discloses a dry gas seal assembly and vacuum pump, the dry gas seal assembly includes fixed seat, elastic element, rotating ring and fixed ring. Wherein, fixed seat is set with accommodation cavity, and elastic element, rotating ring and fixed ring are all located in the accommodation cavity. And, fixed ring is located between rotating ring and elastic element. In the application, the elastic element includes ring part and at least two elastic parts arranged on the ring part along the circumference, and the fixed ring is used to be close to the rotating ring under the action of the elastic part. Based on this, there is always a tendency of sticking together between the fixed ring and the rotating ring. On the basis, a plurality of spiral gas guide grooves are arranged on the side of the rotating ring close to the elastic part along the circumference, the spiral gas guide groove forms a gas film with certain rigidity by accurately controlling the path and pressure of airflow, thereby effectively sealing to prevent fluid medium leakage, and at the same time reducing friction loss and prolonging service life. BRIEF DESCRIPTION OF DRAWINGS

[0005] In order to more clearly illustrate the technical scheme of the embodiments of the utility model, the following will be briefly introduced to the drawings needed to be used in the embodiment, it should be understood that the following drawings only shows some embodiments of the utility model, therefore should not be regarded as the limitation to the scope, for the ordinary skilled person in the art, under the premise of not paying the creative labor, can also obtain other related drawings according to these drawings.

[0006] Figure 1 The structure schematic diagram of the vacuum pump applied to the dry gas seal assembly provided by the embodiments of the utility model is shown in the following figure.

[0007] Figure 2 The dry gas seal assembly provided by the embodiments of the utility model is shown in the following figure. Figure 1 The cross-sectional view of A-A in the above figure is shown in the following figure.

[0008] Figure 3A structure schematic view of the dry gas seal assembly is provided in the embodiment of the present application.

[0009] Figure 4 A structure schematic view of the rotating ring is provided in the embodiment of the present application.

[0010] Icon: 1-vacuum pump;10-dry gas seal assembly;100-fixed seat;300-elastic element;310-ring part;330-elastic part;331-inclined block;333-pressing block;500-rotating ring;510-spiral air guide groove;530-sealing dam;700-fixed ring;900-clasp spring;20-oil throwing disc;30-bearing pressing plate;40-bearing;50-O-shaped ring;60-lip seal;70-shaft sleeve;80-gear assembly;90-rotor shaft. DETAILED DESCRIPTION

[0011] In the radial seal in the related art, two ways of gap seal and elastic material contact seal are generally adopted. However, the gap seal cannot achieve complete sealing, and is easy to affect the stability of the vacuum degree; the elastic material is gradually worn out, resulting in a decline in the sealing effect.

[0012] In view of the above problems, the present application provides a dry gas seal assembly 10 and a vacuum pump 1, which can form a gas film with certain rigidity by accurately controlling the path and pressure of the airflow, thereby effectively sealing to prevent fluid medium leakage, and simultaneously reducing friction loss and prolonging the service life.

[0013] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0014] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0015] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0016] In the description of the utility model, it needs to explain, if the terms "upper", "lower", "inner", "outer" and so on indicate the orientation or position relationship is based on the orientation or position relationship shown in the drawing, or is the orientation or position relationship of the utility model product when using, only for the convenience of describing the utility model and simplifying the description, and cannot indicate or imply that the device or element must have a specific orientation, structure and operation, therefore cannot be understood as a limitation on the utility model.

[0017] In addition, if the terms "first", "second" and so on are only used for differentiation, and cannot be understood as indicating or implying relative importance.

[0018] It needs to be explained that the features in the embodiments of the utility model can be combined with each other without conflict.

[0019] The overall structure, working principle and technical effects of the dry gas seal assembly 10 and the vacuum pump 1 provided by the utility model are described in detail below by combining with the drawings.

[0020] Figure 1 The structure diagram of the vacuum pump 1 applied by the dry gas seal assembly 10 provided by the embodiments of the utility model, Figure 2 The dry gas seal assembly 10 provided by the embodiments of the utility model, Figure 1 The cross-sectional view at A-A, Figure 3 The structure diagram of the dry gas seal assembly 10 provided by the embodiments of the utility model. Please refer to Figures 1 to 3 The embodiments provide a dry gas seal assembly 10 applied to a vacuum pump 1 to achieve the purpose of reducing friction loss and prolonging service life while effectively sealing to prevent fluid medium leakage.

[0021] As Figure 2 shown, the vacuum pump 1 includes a rotor shaft 90 and a rotor installed on the rotor shaft 90. The oil throwing disc 20, bearing pressing plate 30, bearing 40, dry gas seal assembly 10, O-ring 50, lip seal 60 and shaft sleeve 70 are installed on the rotor shaft 90 on the axial side of the rotor along the axial direction. It is easy to understand that the introduction of the dry gas seal assembly 10 between the bearing 40 and the rotor can effectively reduce the amount of dust entering the bearing 40, prolong the service life of the bearing 40, and thus improve the reliability of the vacuum pump 1 and prolong the maintenance period of the vacuum pump 1.

[0022] Specifically, when the rotor shaft 90 rotates, the injected high-pressure gas makes the dry gas seal assembly 10 form a stable high-pressure gas film. Since the pressure of the high-pressure gas film is sufficient to overcome the impact force of the external dust particles, it can act as a gas barrier to effectively block the dust from entering the lubricating oil, ensuring the cleanliness of the lubricating oil, thereby prolonging the service life of the vacuum pump 1 and improving its operating efficiency.

[0023] In some embodiments, the bearing 40, the dry gas seal assembly 10, the rotor, the dry gas seal assembly 10 and the bearing 40 can be symmetrically installed on the rotor shaft 90 in the order of the bearing 40, the dry gas seal assembly 10, the rotor, the dry gas seal assembly 10 and the bearing 40. Alternatively, as shown in Figure 2 the above-mentioned components (i.e. the oil slinger 20, the bearing pressing plate 30, the bearing 40, the dry gas seal assembly 10, the O-ring 50, the lip seal 60 and the shaft sleeve 70) can be symmetrically arranged at both ends of the rotor shaft 90 to further improve the reliability of the vacuum pump 1. In addition, the vacuum pump 1 can further comprise a gear assembly 80 connected to the rotor shaft 90, which is located on the other side of the rotor in the axial direction.

[0024] In addition, it should be noted that, based on the characteristics of the dry gas seal assembly 10 being insensitive to temperature and pressure, the dry gas seal assembly 10 is widely used in other environments in addition to being applied in the above-mentioned vacuum pump 1. For example, the dry gas seal assembly 10 can work in a high-temperature environment, such as a high-temperature reactor, an engine turbine, etc.; it can also work in a low-temperature environment, such as a low-temperature storage tank, a liquefied natural gas processing device, etc.; it can also work in a high-pressure environment, such as a high-pressure gas transmission pipeline, a compressor, etc.; and it can also work in a low-pressure environment, such as a vacuum system, a low-pressure gas storage container, etc.

[0025] Please refer to Figure 3 again, and the dry gas seal assembly 10 will be described in detail below. The dry gas seal assembly 10 comprises a fixed seat 100, an elastic element 300, a rotating ring 500 and a fixed ring 700. The fixed seat 100 has a receiving cavity, and the elastic element 300, the rotating ring 500 and the fixed ring 700 are located in the receiving cavity. In addition, the fixed ring 700 is located between the rotating ring 500 and the elastic element 300.

[0026] In this application, the elastic element 300 comprises a ring portion 310 and at least two elastic portions 330 spaced apart along the circumference of the ring portion 310, and the fixed ring 700 is arranged to be close to the rotating ring 500 under the action of the elastic portions 330. Based on this, there is always a tendency for the fixed ring 700 and the rotating ring 500 to fit together, and they are in a state of fitting together or in a state of maintaining a very small gap, which has the precondition of compressing the gas and forming the gas film.

[0027] On the basis of the above, a plurality of spiral gas guide grooves 510 are spaced apart along the circumference on the side of the rotating ring 500 close to the elastic portions 330. It is easy to understand that when the rotating ring 500 starts to rotate at high speed, the gas is brought into the spiral gas guide grooves 510 due to the viscous shear force of the gas. Again, due to the shape of the spiral gas guide grooves 510, the gas is gradually compressed and the gas film pressure gradually increases during the movement of the gas from the outer diameter of the rotating ring 500 to the center.

[0028] With the increase of the gas film pressure, a gas film with certain rigidity and thickness (generally several microns) is formed. It can be understood that the gas film provides sufficient pressure to resist the closing force generated by the spring load of the elastic part 330, so that a stable, non-contact running gap is formed between the rotating ring 500 and the fixed ring 700.

[0029] It should be noted that based on the existence of the above-mentioned gas film, on the one hand, the non-contact operation between the rotating ring 500 and the fixed ring 700 is formed, the friction loss is reduced, the lubrication effect is provided, and the service life of the equipment is prolonged. On the other hand, the leakage of the fluid medium can be effectively prevented, and high-precision and long-life sealing is achieved.

[0030] In addition, it should be noted that the direction of the gas flow is designed according to the state of the suction gas, which is generally consistent with the rotation direction of the rotating ring 500, so as to maximize the pressure effect of the gas. Generally, the faster the rotating speed of the rotating ring 500, the greater the rigidity of the gas film generated, and the better the sealing effect.

[0031] It is considered that the spiral gas guide groove 510 is designed to utilize the hydrodynamic pressure effect to generate a gas film to achieve non-contact operation between the sealing surfaces, and the groove depth that is too deep or too shallow will affect the generation of the hydrodynamic pressure effect and the stability of the gas film. In this embodiment, the groove depth of the spiral gas guide groove 510 ranges from 0.05 mm to 0.2 mm, thereby avoiding that the too small groove depth affects the sealing effect and the too large groove depth increases the wear and leakage.

[0032] Figure 4 For the structure diagram of the rotating ring 500 provided by the embodiment of the utility model, please refer to Figure 4 In order to increase the resistance of the gas flow, the spiral gas guide groove 510 is provided with a sealing dam 530 at one end close to the rotation axis of the rotating ring 500. It should be noted that based on the existence of the above-mentioned sealing dam 530, the gas flow to the rotation axis of the rotating ring 500 can be prevented, so that the gas is further compressed, thereby further increasing the pressure of the gas film. In addition, it should be noted that in order to facilitate the entry of the gas, the other end of the spiral gas guide groove 510 away from the rotation axis of the rotating ring 500 extends to the outer end surface of the rotating ring 500, which is in an open shape.

[0033] In other embodiments, the one end of the spiral gas guide groove 510 close to the rotation axis of the rotating ring 500 can also be extremely narrow to further compress the gas. Correspondingly, in order to further compress the gas and increase the gas pressure during the movement of the gas from the outer diameter of the rotating ring 500 to the center, the groove width of the spiral gas guide groove 510 gradually decreases along the direction close to the rotation axis of the rotating ring 500.

[0034] It should be noted that, due to the very small thickness of the gas film between the fixed ring 700 and the rotating ring 500, high flatness can ensure that the gas film is more evenly distributed on the surface of the rotating ring 500, thereby increasing the pressure at the center of the gas film. Based on this, the flatness of the two opposite sides of the fixed ring 700 and the rotating ring 500, as well as the groove surface of the spiral gas guide groove 510, needs to meet certain requirements to enhance the stability of the gas film and improve the sealing effect.

[0035] In addition, it should be noted that the spiral gas guide groove 510 has good groove depth consistency, which can ensure uniform gas film thickness and avoid the situation of local gas film being too thin or too thick. Based on this, improving the groove depth consistency of all spiral gas guide grooves 510 can improve the stability of the gas film, reduce the risk of local gas film leakage, and further enhance the sealing performance. It is easy to understand that the spiral gas guide grooves 510 are equidistantly spaced along the circumference of the rotating ring 500 and are evenly distributed.

[0036] Please refer again to Figure 3 In some embodiments, the dry gas seal assembly 10 also includes a snap spring 900 located in the accommodation cavity and abutting the side of the fixed ring 700 away from the elastic part 330. It is easy to understand that by introducing the snap spring 900, the pressure exerted by the elastic part 330 on the fixed ring 700 can be effectively controlled, avoiding excessive elastic force of the elastic part 330, thereby preventing the fixed ring 700 from being separated from the accommodation cavity.

[0037] That is, the snap spring 900 can firmly abut against the fixed ring 700 to ensure its stable position in the accommodation cavity. Therefore, the stably fixed fixed ring 700 reduces the friction and wear between moving parts, prolonging the service life of the dry gas seal assembly 10. In addition, to improve the connection stability of the snap spring 900 and the fixed seat 100, the cavity wall of the accommodation cavity can be provided with an accommodation groove, and the snap spring 900 cooperates with the accommodation groove.

[0038] Please refer again to Figure 3 In some embodiments, the ring part 310, the fixed ring 700 and the rotating ring 500 are coaxially arranged. It can be understood that coaxial arrangement helps to form uniform gas film distribution, reduces local leakage caused by eccentricity, and thus improves the overall sealing performance of the dry gas seal assembly 10.

[0039] In addition, coaxial arrangement also reduces vibration caused by misalignment of parts, ensures the stability of the rotating ring 500 during high-speed rotation, reduces local wear caused by eccentric movement, and prolongs the service life of the dry gas seal assembly 10. Optionally, the snap spring 900 is also coaxially arranged with the ring part 310, the fixed ring 700 and the rotating ring 500.

[0040] To further improve the reliability of the dry gas seal assembly 10, all the elastic parts 330 are equidistantly spaced along the circumference of the ring part 310. It is easy to understand that the equidistantly spaced elastic parts 330 can uniformly apply pressure to ensure that the force at each point is balanced. Based on this, on the one hand, local deformation or wear caused by excessive local pressure can be avoided, and on the other hand, the dynamic stability of the dry gas seal assembly 10 can be improved, so that it performs better under dynamic conditions such as high-speed rotation.

[0041] In some embodiments, the elastic part 330 includes an inclined block 331. One end of the inclined block 331 is connected with the ring part 310, and the other end is inclined towards the end close to the fixed ring 700. Based on this, with the dynamic floating of the fixed ring 700, the inclined block 331 can adaptively change according to the direction and degree of floating, and open outward or close inward, so as to adjust the pressure applied to the fixed ring 700 as needed.

[0042] In particular, the inclined design of the inclined block 331, on the one hand, can reduce the direct impact on the fixed ring 700 during floating, thereby improving the durability of the dry gas seal assembly 10; on the other hand, it helps to adjust the force acting on the fixed ring 700, so as to ensure that the fixed ring 700 has the tendency to fit the rotating ring 500 without excessive displacement, thereby ensuring stable gas film formation and sealing performance.

[0043] In other embodiments, the elastic part 330 can be provided as a spring connected at one end with the ring part 310, which can adjust the pressure applied to the fixed ring 700 as needed to ensure the stability of the gas film and sealing effect, and the like. This embodiment will not be described again.

[0044] Further, the elastic part 330 further includes an abutting block 333. One end of the abutting block 333 is connected with the end of the inclined block 331 away from the ring part 310, and the other end abuts against the fixed ring 700. It is easy to understand that the abutting block 333 increases the contact area between the elastic part 330 and the fixed ring 700, thereby on the one hand ensuring that the force applied to the fixed ring 700 is more uniform, and on the other hand ensuring that the force applied to the fixed ring 700 remains stable.

[0045] In addition, it also needs to be supplemented that the fixed ring 700 is one of the main elements of the mechanical seal, which is easy to move under the action of the elastic element 300 and the gas film, and the contact surface is most likely to leak or even be damaged due to the combined action of heat, chemistry, physics and mechanics. Therefore, the fixed ring 700 is generally made of wear-resistant materials to reduce wear and prolong service life, thereby improving the reliability and stability of the entire sealing system.

[0046] With the example of the embodiment, the working process and working principle of the dry gas seal assembly 10 provided by the application are as follows:

[0047] In the case that the rotating ring 500 rotates with the rotor shaft 90, the sealing gas is sucked into the spiral exhaust groove along the circumference due to the viscous shear force of the gas, and flows toward the rotating center of the rotating ring 500 from the opening portion on the outer circumferential surface of the rotating ring 500. In this process, the groove width of the spiral exhaust groove gradually decreases, and the gas is gradually compressed. The presence of the sealing dam 530 prevents the gas from flowing to the rotating axis of the rotating ring 500, thereby further increasing the resistance of the gas flow, and further compressing the gas.

[0048] It is easy to understand that the fluid film pressure generated thereby separates the rotating ring 500 and the fixed ring 700, and forms a gas film with a typical value of several microns of the balance gap or film thickness. Based on this, after the three forces of the pneumatic force, the spring force and the fluid dynamic pressure opening force are balanced, the gas film has good elasticity (i.e. the gas film stiffness), forms a stable operation and prevents the sealing end surfaces of the rotating ring 500 and the fixed ring 700 from contacting each other. Moreover, the gas film completely blocks the leakage passage of the relatively low pressure sealing medium, achieving zero leakage or zero escape of the sealing medium.

[0049] In summary, the dry gas seal assembly 10 and the vacuum pump 1 are provided. The dry gas seal assembly 10 comprises a fixed seat 100, an elastic element 300, a rotating ring 500 and a fixed ring 700. The fixed seat 100 is provided with a containing cavity, and the elastic element 300, the rotating ring 500 and the fixed ring 700 are located in the containing cavity. Moreover, the fixed ring 700 is located between the rotating ring 500 and the elastic element 300. In the application, the elastic element 300 comprises a ring portion 310 and at least two elastic portions 330 which are spaced apart along the circumference of the ring portion 310, and the fixed ring 700 is used to be close to the rotating ring 500 under the action of the elastic portion 330. Based on this, the fixed ring 700 and the rotating ring 500 always have a tendency to fit together. On the basis of the above, a plurality of spiral gas guide grooves 510 are spaced apart along the circumference on the side of the rotating ring 500 close to the elastic portion 330, and the spiral gas guide grooves 510 form a gas film with a certain stiffness by precisely controlling the path and pressure of the gas flow, thereby effectively sealing to prevent the leakage of the fluid medium, and at the same time reducing the friction loss and prolonging the service life.

[0050] The above is only a specific embodiment of the application, but the protection scope of the application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the application, which should be covered within the protection scope of the application.

Claims

1. A dry gas seal assembly comprising: The dry gas seal assembly (10) comprises: a fixing seat (100) having a receiving cavity; an elastic element (300) located in the receiving cavity, and comprising a ring portion (310) and at least two elastic portions (330) spaced along the circumference of the ring portion (310); a rotating ring (500) located in the receiving cavity, and having a plurality of spiral gas guide grooves (510) spaced along the circumference of the side close to the elastic portions (330); a fixing ring (700) located between the rotating ring (500) and the elastic element (300), and used to be close to the rotating ring (500) under the action of the elastic portions (330).

2. The dry gas seal assembly of claim 1, wherein, The elastic portion (330) comprises an inclined block (331) having one end connected to the ring portion (310) and the other end inclined towards the end close to the fixing ring (700).

3. The dry gas seal assembly of claim 2, wherein, The elastic portion (330) further comprises a bearing block (333) having one end connected to the end of the inclined block (331) away from the ring portion (310) and the other end bearing against the fixing ring (700).

4. The dry gas seal assembly of claim 1, wherein, All the elastic portions (330) are equidistantly spaced along the circumference of the ring portion (310).

5. The dry gas seal assembly of claim 1, wherein, The ring portion (310), the fixing ring (700) and the rotating ring (500) are coaxially arranged.

6. The dry gas seal assembly of any one of claims 1 to 5, wherein, The spiral gas guide groove (510) has a groove depth ranging from 0.05 mm to 0.2 mm.

7. The dry gas seal assembly of any of claims 1 to 5, wherein, The spiral gas guide groove (510) has a sealing dam (530) at the end close to the rotation axis of the rotating ring (500).

8. The dry gas seal assembly of any of claims 1 to 5, wherein, The groove width of the spiral gas guide groove (510) gradually decreases along the direction close to the rotation axis of the rotating ring (500).

9. The dry gas seal assembly of any of claims 1 to 5, wherein, The dry gas seal assembly (10) further comprises a snap spring (900) located in the receiving cavity and bearing against the side of the fixing ring (700) away from the elastic portions (330).

10. A vacuum pump, characterized by The dry gas seal assembly (10) comprises the dry gas seal assembly (10) according to any one of claims 1-9.

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