Labyrinth lip seal structure and roots vacuum pump using the same

Abstract

The utility model relates to combined sealing structure technical field, especially labyrinth lip seal structure and the roots vacuum pump of applying it. Including: the shaft sleeve of installing in the end cover inside, set up between the labyrinth seal of the shaft sleeve with the end cover, set up the lip seal of the adjacent side of the labyrinth seal, set up the skeleton oil seal of the adjacent side of the lip seal and the bearing of abutting the skeleton oil seal adjacent side setting, the labyrinth seal, the lip seal and the skeleton oil seal all cover the outer diameter surface of the shaft sleeve, the end face of the bearing one side and the end face of the shaft sleeve abut. The utility model provides a kind of labyrinth lip seal structure and the roots vacuum pump of applying it with the advantages such as good sealing effect, little wear, long service life and convenient to use.

Description

Technical Field

[0001] This utility model relates to the field of combined sealing structure technology, and in particular to a labyrinth lip seal structure and a Roots vacuum pump using the same. Background Technology

[0002] A pump is a machine that transports or pressurizes fluids. It transfers the mechanical energy of a prime mover or other external energy to the liquid, increasing the liquid's energy. Existing pumps have various internal sealing structures, including mechanical seals, combined seals, and clearance seals.

[0003] Chinese patent CN221838537U discloses a sealing structure combining a lip seal and a piston ring, including a housing with a working chamber inside. A bearing seat is fixedly connected to the left end of the housing, and a bearing cavity is provided in the center of the end face of the bearing seat near one end of the housing. A through hole is provided on the housing to connect the bearing cavity and the working chamber. A bearing is provided in the bearing cavity, and an oil retainer ring is provided at the right end of the bearing. A rotor is provided in the working chamber. Compared with the traditional multi-piston ring sealing method, this utility model, by adding a first O-ring seal, a second O-ring seal, and a lip seal, can effectively prevent dust or other media that may contaminate the lubricating oil from entering the bearing cavity from the working cavity, greatly enhancing the sealing performance between the working cavity and the bearing cavity.

[0004] However, this technical solution, which uses a combination of multiple sealing rings and lip seals to seal, can only prevent one-way leakage between the inner cavity and the bearing. That is, it can only achieve one-way sealing, which is not effective. In addition, the O-rings are prone to friction and heat generation during use, which can lead to aging and short service life. Utility Model Content

[0005] One of the objectives of this utility model is to address the shortcomings of existing technologies by providing a labyrinth lip seal structure. This structure achieves a three-stage series seal through a labyrinth seal, a lip seal, and a skeleton oil seal. The skeleton oil seal abuts against the bearing, and the labyrinth seal completely fills the gap between the end cover and the bushing, thus achieving a bidirectional seal and ensuring a good sealing effect.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A labyrinth lip seal structure, characterized in that it comprises: a bushing installed inside an end cover, a labyrinth seal disposed between the bushing and the end cover, a lip seal disposed adjacent to the labyrinth seal, a skeleton oil seal disposed adjacent to the lip seal, and a bearing disposed adjacent to the skeleton oil seal. The labyrinth seal, the lip seal, and the skeleton oil seal are all sleeved on the outer diameter surface of the bushing, and the end face of one side of the bearing abuts against the end face of the bushing.

[0007] Preferably, a positioning ring is provided between the lip seal and the skeleton oil seal.

[0008] Preferably, an air inlet is provided on one side of the end cap.

[0009] Preferably, the air inlet is positioned directly opposite the labyrinth seal.

[0010] Preferably, a pressure relief hole is provided on the other side of the end cap.

[0011] Preferably, the pressure relief hole is located on the outer side of the junction between the skeleton oil seal and the lip seal, and the pressure relief hole is positioned directly opposite the positioning ring.

[0012] Preferably, the outer periphery of the bushing is provided with a protective coating, and the labyrinth seal, the lip seal, and the skeleton oil seal are sequentially installed on the protective coating.

[0013] Preferably, the width of the labyrinth seal, the lip seal, and the skeleton oil seal combined together is adapted to the width of the bushing.

[0014] Preferably, the end of the end cap near the bearing is the oil tank side, and the end of the end cap near the bushing is the pump chamber side.

[0015] Another objective of this invention is to address the shortcomings of existing technologies by providing a Roots vacuum pump. This pump installs a sealing structure between the rotor's bushing and the end cover to ensure the overall sealing of the vacuum pump, preventing leakage during operation and achieving zero leakage. This makes the pump easy to use.

[0016] To achieve the above objectives, this utility model provides the following technical solution: A Roots vacuum pump includes: a pump body, end caps disposed at both ends of the pump body, and a rotor disposed inside the pump body, and further includes: a labyrinth lip seal structure as described above, the seal structure being installed at the junction of the end caps and the bushing.

[0017] The beneficial effects of this utility model are as follows: (1) This utility model forms a multi-level gradient seal by fitting the labyrinth seal, lip seal and skeleton oil seal on the outer diameter surface of the bushing, ensuring that the lubricating oil does not leak out and external contaminants do not enter the end cover. It has a better sealing effect than mechanical seal. The end face of the bearing side abuts against the end face of the bushing. Direct contact can shorten the axial dimension and improve the overall rigidity.

[0018] (2) This utility model provides an air inlet on one side of the end cap to introduce an inert gas, such as nitrogen, to form an air seal. This can prevent the oil mist in the pump chamber from spreading outward and can also blow away dust and other impurities or pollutants in the pump chamber, ensuring that the pump chamber is clean and tidy. The air inlet is set directly opposite the labyrinth seal, so that the airflow can directly enter the labyrinth seal. Because there is a certain path inside, it plays a guiding role. At this time, the protective gas entering is under positive pressure, which can remove the dust in the chamber and ensure that the airflow can pass smoothly, which enhances the blowing effect, thereby reducing the wear of the labyrinth seal and extending its service life.

[0019] (3) This utility model provides a pressure relief hole on the other side of the end cap. The pressure relief hole is located on the outside of the junction of the skeleton oil seal and the lip seal. The protective gas is discharged from the pressure relief hole, which will not form a high pressure zone between the lip seal and the skeleton oil seal. It will only form normal pressure and will not affect the overall sealing performance. The pressure relief hole is set directly opposite the positioning ring, which can avoid the pressure relief hole being opened on the outer diameter surface of the skeleton oil seal, thereby reducing its aging risk and ensuring its service life.

[0020] In summary, this utility model has the advantages of good sealing effect, less wear, long service life and convenient use. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of Embodiment 1 of the present utility model; Figure 2 for Figure 1 A sectional view taken from point AA; Figure 3 for Figure 2 Enlarged view of point C; Figure 4 for Figure 1 A sectional view taken from point BB; Figure 5 This is a structural diagram of the bushing according to Embodiment 1 of this utility model; Figure 6 This is a structural schematic diagram of Embodiment 2 of the present invention. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] In the description of this utility model, 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," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0024] Example 1 like Figures 1-5 As shown, this embodiment provides a labyrinth lip seal structure, mainly suitable for high dust conditions. It includes: a bushing 2 installed inside the end cover 1; a labyrinth seal 3 disposed between the bushing 2 and the end cover 1; a lip seal 4 disposed adjacent to the labyrinth seal 3; a skeleton oil seal 5 disposed adjacent to the lip seal 4; and a bearing 6 disposed adjacent to the skeleton oil seal 5. The labyrinth seal 3, lip seal 4, and skeleton oil seal 5 are all fitted onto the outer diameter surface of the bushing 2, forming a multi-stage gradient seal to ensure that lubricating oil does not leak out and external contaminants do not enter the end cover 1, providing a better sealing effect than a mechanical seal. One end face of the bearing 6 abuts against the end face of the bushing 2; direct contact can shorten the axial dimension and improve overall rigidity.

[0025] A positioning ring 7 is provided between the lip seal 4 and the skeleton oil seal 5 to ensure axial positioning between the lip seal 4 and the skeleton oil seal 5 and to avoid overpressure or underpressure caused by assembly errors.

[0026] Meanwhile, an air inlet 11 is provided on one side of the end cap 1 to introduce inert gas, such as nitrogen, to form an air seal, which can prevent oil mist in the pump chamber from spreading outward, and can also blow away dust and other impurities or pollutants in the pump chamber to ensure that the pump chamber is clean and tidy.

[0027] In this embodiment, the air inlet 11 is positioned directly opposite the labyrinth seal 3, and more preferably, the air inlet 11 is positioned at the junction of the labyrinth seal 3 and the lip seal 4, so that the airflow directly enters the interior of the labyrinth seal 3. Since there is a certain path inside, it plays a guiding role. At this time, the protective gas entering is under positive pressure, which can remove the dust in the chamber, ensuring smooth airflow, enhancing the purging effect, thereby reducing the wear of the labyrinth seal 3 and extending its service life.

[0028] In this embodiment, a pressure relief hole 12 is provided on the other side of the end cap 1. The pressure relief hole 12 is located on the outside of the junction of the skeleton oil seal 5 and the lip seal 4. Protective gas is discharged from the pressure relief hole 12, which will not form a high-pressure area between the lip seal 4 and the skeleton oil seal 5, but will only form normal pressure, which will not affect the overall sealing performance. Moreover, the pressure relief hole 12 is set directly opposite the positioning ring 7, which can avoid the pressure relief hole 12 being opened on the outer diameter surface of the skeleton oil seal 5, thereby reducing its aging risk and ensuring its service life. The outer diameter surface of the positioning ring 7 usually has a radial groove or notch, which can directly connect the pressure relief hole 12 to the chamber, making the pressure relief channel the shortest and the back pressure the smallest.

[0029] In this embodiment, a protective coating 21 is provided on the outer periphery of the bushing 2. The labyrinth seal 3, the lip seal 4, and the skeleton oil seal 5 are sequentially installed on the protective coating 21, which can reduce the wear of the bushing 2 and make it more corrosion resistant.

[0030] In this embodiment, the protective coating 21 is made of silicon carbide, with a thickness of 0.2 mm. It has extremely high hardness and can effectively resist friction and wear between the bushing 2 and sealing components such as the labyrinth seal 3, thus extending the service life of the bushing 2.

[0031] In this embodiment, the width of the labyrinth seal 3, the lip seal 4, and the skeleton oil seal 5 combined is adapted to the width of the bushing 2. Preferably, the width of the three combined just fills the inner cavity of the end cap 1, eliminating the need for additional gaskets and simplifying the process.

[0032] Of course, the end of the end cover 1 near the bearing 6 is the oil tank side 13, and the end of the end cover 1 near the bushing 2 is the pump chamber side 14. The functional divisions on both sides are clear. The oil tank side 13 is mainly sealed with skeleton seal plus lubricating oil, while the pump chamber side 14 is sealed with inert gas, lip seal 4 and labyrinth seal 3 in a three-in-one manner. During maintenance, it is only necessary to remove the end cover 1 to determine which side the leak comes from. The operation is simple and convenient.

[0033] In addition, the end cap 1 has two cavities 15 inside, which are used to install the active rotor and the driven rotor respectively. The active rotor needs to be sealed by sealing components such as labyrinth seal 3, lip seal 4 and skeleton oil seal 5, while the driven rotor is generally sealed by clearance fit. The cavity 15 is provided with an oil inlet 16 for introducing lubricating oil, which can not only ensure sealing, but also reduce rotor wear and thus extend its service life.

[0034] Example 2 like Figure 6 As shown, components that are the same as or corresponding to those in Embodiment 1 are referred to using the same reference numerals as in Embodiment 1. For simplicity, only the differences from Embodiment 1 are described below. The difference between Embodiment 2 and Embodiment 1 is as follows: This embodiment provides a Roots vacuum pump, including: a pump body 100, end caps 1 disposed at both ends of the pump body 100, and a rotor 200 disposed inside the pump body 100. It also includes: a labyrinth lip seal structure as described in Embodiment 1. This sealing structure is installed at the junction of the end caps 1 and the bushing 2. This sealing structure is composed of a multi-stage seal combination, forming multiple barriers to the high-pressure gas inside the pump, with excellent sealing effect. Especially for the micro-gap conditions of the Roots pump, it can effectively block the molecular-level leakage of process gas to the atmosphere, meeting the actual requirement of zero leakage.

[0035] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A labyrinth lip seal structure characterized by, include: The assembly includes a bushing installed inside the end cover, a labyrinth seal disposed between the bushing and the end cover, a lip seal disposed adjacent to the labyrinth seal, a skeleton oil seal disposed adjacent to the lip seal, and a bearing disposed adjacent to the skeleton oil seal. The labyrinth seal, the lip seal, and the skeleton oil seal are all fitted onto the outer diameter surface of the bushing, and the end face of one side of the bearing abuts against the end face of the bushing.

2. A labyrinth lip seal structure according to claim 1, wherein A positioning ring is provided between the lip seal and the skeleton oil seal.

3. A labyrinth lip seal structure according to claim 1, wherein An air inlet is provided on one side of the end cap.

4. A labyrinth lip seal structure according to claim 3, wherein The air intake is positioned directly opposite the labyrinth seal.

5. A labyrinth lip seal structure according to claim 1 wherein, A pressure relief hole is provided on the other side of the end cap.

6. A labyrinth lip seal structure according to claim 5, wherein The pressure relief hole is located on the outside of the junction of the skeleton oil seal and the lip seal.

7. A labyrinth lip seal structure according to claim 1 wherein, The outer periphery of the bushing is provided with a protective coating, and the labyrinth seal, the lip seal, and the skeleton oil seal are sequentially installed on the protective coating.

8. A labyrinth lip seal structure according to claim 1 wherein, The width of the labyrinth seal, the lip seal, and the skeleton oil seal combined together is adapted to the width of the bushing.

9. A labyrinth lip seal structure according to claim 1 wherein, The end of the end cap near the bearing is the oil tank side, and the end of the end cap near the bushing is the pump chamber side.

10. A Roots vacuum pump comprising: The pump body, end caps disposed at both ends of the pump body, and rotor disposed inside the pump body are characterized in that they further include: a labyrinth lip seal structure as described in any one of claims 1-9, wherein the seal structure is installed at the junction of the end caps and the bushing.

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